fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 key.type = BTRFS_EXTENT_DATA_KEY;
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end > PAGE_CACHE_SIZE ||
 253             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 static inline int inode_need_compress(struct inode *inode)
 352 {
 353         struct btrfs_root *root = BTRFS_I(inode)->root;
 354
 355         /* force compress */
 356         if (btrfs_test_opt(root, FORCE_COMPRESS))
 357                 return 1;
 358         /* bad compression ratios */
 359         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 360                 return 0;
 361         if (btrfs_test_opt(root, COMPRESS) ||
 362             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 363             BTRFS_I(inode)->force_compress)
 364                 return 1;
 365         return 0;
 366 }
 367
 368 /*
 369  * we create compressed extents in two phases.  The first
 370  * phase compresses a range of pages that have already been
 371  * locked (both pages and state bits are locked).
 372  *
 373  * This is done inside an ordered work queue, and the compression
 374  * is spread across many cpus.  The actual IO submission is step
 375  * two, and the ordered work queue takes care of making sure that
 376  * happens in the same order things were put onto the queue by
 377  * writepages and friends.
 378  *
 379  * If this code finds it can't get good compression, it puts an
 380  * entry onto the work queue to write the uncompressed bytes.  This
 381  * makes sure that both compressed inodes and uncompressed inodes
 382  * are written in the same order that the flusher thread sent them
 383  * down.
 384  */
 385 static noinline void compress_file_range(struct inode *inode,
 386                                         struct page *locked_page,
 387                                         u64 start, u64 end,
 388                                         struct async_cow *async_cow,
 389                                         int *num_added)
 390 {
 391         struct btrfs_root *root = BTRFS_I(inode)->root;
 392         u64 num_bytes;
 393         u64 blocksize = root->sectorsize;
 394         u64 actual_end;
 395         u64 isize = i_size_read(inode);
 396         int ret = 0;
 397         struct page **pages = NULL;
 398         unsigned long nr_pages;
 399         unsigned long nr_pages_ret = 0;
 400         unsigned long total_compressed = 0;
 401         unsigned long total_in = 0;
 402         unsigned long max_compressed = 128 * 1024;
 403         unsigned long max_uncompressed = 128 * 1024;
 404         int i;
 405         int will_compress;
 406         int compress_type = root->fs_info->compress_type;
 407         int redirty = 0;
 408
 409         /* if this is a small write inside eof, kick off a defrag */
 410         if ((end - start + 1) < 16 * 1024 &&
 411             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 412                 btrfs_add_inode_defrag(NULL, inode);
 413
 414         actual_end = min_t(u64, isize, end + 1);
 415 again:
 416         will_compress = 0;
 417         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 418         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 419
 420         /*
 421          * we don't want to send crud past the end of i_size through
 422          * compression, that's just a waste of CPU time.  So, if the
 423          * end of the file is before the start of our current
 424          * requested range of bytes, we bail out to the uncompressed
 425          * cleanup code that can deal with all of this.
 426          *
 427          * It isn't really the fastest way to fix things, but this is a
 428          * very uncommon corner.
 429          */
 430         if (actual_end <= start)
 431                 goto cleanup_and_bail_uncompressed;
 432
 433         total_compressed = actual_end - start;
 434
 435         /*
 436          * skip compression for a small file range(<=blocksize) that
 437          * isn't an inline extent, since it dosen't save disk space at all.
 438          */
 439         if (total_compressed <= blocksize &&
 440            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 441                 goto cleanup_and_bail_uncompressed;
 442
 443         /* we want to make sure that amount of ram required to uncompress
 444          * an extent is reasonable, so we limit the total size in ram
 445          * of a compressed extent to 128k.  This is a crucial number
 446          * because it also controls how easily we can spread reads across
 447          * cpus for decompression.
 448          *
 449          * We also want to make sure the amount of IO required to do
 450          * a random read is reasonably small, so we limit the size of
 451          * a compressed extent to 128k.
 452          */
 453         total_compressed = min(total_compressed, max_uncompressed);
 454         num_bytes = ALIGN(end - start + 1, blocksize);
 455         num_bytes = max(blocksize,  num_bytes);
 456         total_in = 0;
 457         ret = 0;
 458
 459         /*
 460          * we do compression for mount -o compress and when the
 461          * inode has not been flagged as nocompress.  This flag can
 462          * change at any time if we discover bad compression ratios.
 463          */
 464         if (inode_need_compress(inode)) {
 465                 WARN_ON(pages);
 466                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 467                 if (!pages) {
 468                         /* just bail out to the uncompressed code */
 469                         goto cont;
 470                 }
 471
 472                 if (BTRFS_I(inode)->force_compress)
 473                         compress_type = BTRFS_I(inode)->force_compress;
 474
 475                 /*
 476                  * we need to call clear_page_dirty_for_io on each
 477                  * page in the range.  Otherwise applications with the file
 478                  * mmap'd can wander in and change the page contents while
 479                  * we are compressing them.
 480                  *
 481                  * If the compression fails for any reason, we set the pages
 482                  * dirty again later on.
 483                  */
 484                 extent_range_clear_dirty_for_io(inode, start, end);
 485                 redirty = 1;
 486                 ret = btrfs_compress_pages(compress_type,
 487                                            inode->i_mapping, start,
 488                                            total_compressed, pages,
 489                                            nr_pages, &nr_pages_ret,
 490                                            &total_in,
 491                                            &total_compressed,
 492                                            max_compressed);
 493
 494                 if (!ret) {
 495                         unsigned long offset = total_compressed &
 496                                 (PAGE_CACHE_SIZE - 1);
 497                         struct page *page = pages[nr_pages_ret - 1];
 498                         char *kaddr;
 499
 500                         /* zero the tail end of the last page, we might be
 501                          * sending it down to disk
 502                          */
 503                         if (offset) {
 504                                 kaddr = kmap_atomic(page);
 505                                 memset(kaddr + offset, 0,
 506                                        PAGE_CACHE_SIZE - offset);
 507                                 kunmap_atomic(kaddr);
 508                         }
 509                         will_compress = 1;
 510                 }
 511         }
 512 cont:
 513         if (start == 0) {
 514                 /* lets try to make an inline extent */
 515                 if (ret || total_in < (actual_end - start)) {
 516                         /* we didn't compress the entire range, try
 517                          * to make an uncompressed inline extent.
 518                          */
 519                         ret = cow_file_range_inline(root, inode, start, end,
 520                                                     0, 0, NULL);
 521                 } else {
 522                         /* try making a compressed inline extent */
 523                         ret = cow_file_range_inline(root, inode, start, end,
 524                                                     total_compressed,
 525                                                     compress_type, pages);
 526                 }
 527                 if (ret <= 0) {
 528                         unsigned long clear_flags = EXTENT_DELALLOC |
 529                                 EXTENT_DEFRAG;
 530                         unsigned long page_error_op;
 531
 532                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 533                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 534
 535                         /*
 536                          * inline extent creation worked or returned error,
 537                          * we don't need to create any more async work items.
 538                          * Unlock and free up our temp pages.
 539                          */
 540                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 541                                                      clear_flags, PAGE_UNLOCK |
 542                                                      PAGE_CLEAR_DIRTY |
 543                                                      PAGE_SET_WRITEBACK |
 544                                                      page_error_op |
 545                                                      PAGE_END_WRITEBACK);
 546                         goto free_pages_out;
 547                 }
 548         }
 549
 550         if (will_compress) {
 551                 /*
 552                  * we aren't doing an inline extent round the compressed size
 553                  * up to a block size boundary so the allocator does sane
 554                  * things
 555                  */
 556                 total_compressed = ALIGN(total_compressed, blocksize);
 557
 558                 /*
 559                  * one last check to make sure the compression is really a
 560                  * win, compare the page count read with the blocks on disk
 561                  */
 562                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 563                 if (total_compressed >= total_in) {
 564                         will_compress = 0;
 565                 } else {
 566                         num_bytes = total_in;
 567                 }
 568         }
 569         if (!will_compress && pages) {
 570                 /*
 571                  * the compression code ran but failed to make things smaller,
 572                  * free any pages it allocated and our page pointer array
 573                  */
 574                 for (i = 0; i < nr_pages_ret; i++) {
 575                         WARN_ON(pages[i]->mapping);
 576                         page_cache_release(pages[i]);
 577                 }
 578                 kfree(pages);
 579                 pages = NULL;
 580                 total_compressed = 0;
 581                 nr_pages_ret = 0;
 582
 583                 /* flag the file so we don't compress in the future */
 584                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 585                     !(BTRFS_I(inode)->force_compress)) {
 586                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 587                 }
 588         }
 589         if (will_compress) {
 590                 *num_added += 1;
 591
 592                 /* the async work queues will take care of doing actual
 593                  * allocation on disk for these compressed pages,
 594                  * and will submit them to the elevator.
 595                  */
 596                 add_async_extent(async_cow, start, num_bytes,
 597                                  total_compressed, pages, nr_pages_ret,
 598                                  compress_type);
 599
 600                 if (start + num_bytes < end) {
 601                         start += num_bytes;
 602                         pages = NULL;
 603                         cond_resched();
 604                         goto again;
 605                 }
 606         } else {
 607 cleanup_and_bail_uncompressed:
 608                 /*
 609                  * No compression, but we still need to write the pages in
 610                  * the file we've been given so far.  redirty the locked
 611                  * page if it corresponds to our extent and set things up
 612                  * for the async work queue to run cow_file_range to do
 613                  * the normal delalloc dance
 614                  */
 615                 if (page_offset(locked_page) >= start &&
 616                     page_offset(locked_page) <= end) {
 617                         __set_page_dirty_nobuffers(locked_page);
 618                         /* unlocked later on in the async handlers */
 619                 }
 620                 if (redirty)
 621                         extent_range_redirty_for_io(inode, start, end);
 622                 add_async_extent(async_cow, start, end - start + 1,
 623                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 624                 *num_added += 1;
 625         }
 626
 627         return;
 628
 629 free_pages_out:
 630         for (i = 0; i < nr_pages_ret; i++) {
 631                 WARN_ON(pages[i]->mapping);
 632                 page_cache_release(pages[i]);
 633         }
 634         kfree(pages);
 635 }
 636
 637 static void free_async_extent_pages(struct async_extent *async_extent)
 638 {
 639         int i;
 640
 641         if (!async_extent->pages)
 642                 return;
 643
 644         for (i = 0; i < async_extent->nr_pages; i++) {
 645                 WARN_ON(async_extent->pages[i]->mapping);
 646                 page_cache_release(async_extent->pages[i]);
 647         }
 648         kfree(async_extent->pages);
 649         async_extent->nr_pages = 0;
 650         async_extent->pages = NULL;
 651 }
 652
 653 /*
 654  * phase two of compressed writeback.  This is the ordered portion
 655  * of the code, which only gets called in the order the work was
 656  * queued.  We walk all the async extents created by compress_file_range
 657  * and send them down to the disk.
 658  */
 659 static noinline void submit_compressed_extents(struct inode *inode,
 660                                               struct async_cow *async_cow)
 661 {
 662         struct async_extent *async_extent;
 663         u64 alloc_hint = 0;
 664         struct btrfs_key ins;
 665         struct extent_map *em;
 666         struct btrfs_root *root = BTRFS_I(inode)->root;
 667         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 668         struct extent_io_tree *io_tree;
 669         int ret = 0;
 670
 671 again:
 672         while (!list_empty(&async_cow->extents)) {
 673                 async_extent = list_entry(async_cow->extents.next,
 674                                           struct async_extent, list);
 675                 list_del(&async_extent->list);
 676
 677                 io_tree = &BTRFS_I(inode)->io_tree;
 678
 679 retry:
 680                 /* did the compression code fall back to uncompressed IO? */
 681                 if (!async_extent->pages) {
 682                         int page_started = 0;
 683                         unsigned long nr_written = 0;
 684
 685                         lock_extent(io_tree, async_extent->start,
 686                                          async_extent->start +
 687                                          async_extent->ram_size - 1);
 688
 689                         /* allocate blocks */
 690                         ret = cow_file_range(inode, async_cow->locked_page,
 691                                              async_extent->start,
 692                                              async_extent->start +
 693                                              async_extent->ram_size - 1,
 694                                              &page_started, &nr_written, 0);
 695
 696                         /* JDM XXX */
 697
 698                         /*
 699                          * if page_started, cow_file_range inserted an
 700                          * inline extent and took care of all the unlocking
 701                          * and IO for us.  Otherwise, we need to submit
 702                          * all those pages down to the drive.
 703                          */
 704                         if (!page_started && !ret)
 705                                 extent_write_locked_range(io_tree,
 706                                                   inode, async_extent->start,
 707                                                   async_extent->start +
 708                                                   async_extent->ram_size - 1,
 709                                                   btrfs_get_extent,
 710                                                   WB_SYNC_ALL);
 711                         else if (ret)
 712                                 unlock_page(async_cow->locked_page);
 713                         kfree(async_extent);
 714                         cond_resched();
 715                         continue;
 716                 }
 717
 718                 lock_extent(io_tree, async_extent->start,
 719                             async_extent->start + async_extent->ram_size - 1);
 720
 721                 ret = btrfs_reserve_extent(root,
 722                                            async_extent->compressed_size,
 723                                            async_extent->compressed_size,
 724                                            0, alloc_hint, &ins, 1, 1);
 725                 if (ret) {
 726                         free_async_extent_pages(async_extent);
 727
 728                         if (ret == -ENOSPC) {
 729                                 unlock_extent(io_tree, async_extent->start,
 730                                               async_extent->start +
 731                                               async_extent->ram_size - 1);
 732
 733                                 /*
 734                                  * we need to redirty the pages if we decide to
 735                                  * fallback to uncompressed IO, otherwise we
 736                                  * will not submit these pages down to lower
 737                                  * layers.
 738                                  */
 739                                 extent_range_redirty_for_io(inode,
 740                                                 async_extent->start,
 741                                                 async_extent->start +
 742                                                 async_extent->ram_size - 1);
 743
 744                                 goto retry;
 745                         }
 746                         goto out_free;
 747                 }
 748
 749                 /*
 750                  * here we're doing allocation and writeback of the
 751                  * compressed pages
 752                  */
 753                 btrfs_drop_extent_cache(inode, async_extent->start,
 754                                         async_extent->start +
 755                                         async_extent->ram_size - 1, 0);
 756
 757                 em = alloc_extent_map();
 758                 if (!em) {
 759                         ret = -ENOMEM;
 760                         goto out_free_reserve;
 761                 }
 762                 em->start = async_extent->start;
 763                 em->len = async_extent->ram_size;
 764                 em->orig_start = em->start;
 765                 em->mod_start = em->start;
 766                 em->mod_len = em->len;
 767
 768                 em->block_start = ins.objectid;
 769                 em->block_len = ins.offset;
 770                 em->orig_block_len = ins.offset;
 771                 em->ram_bytes = async_extent->ram_size;
 772                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 773                 em->compress_type = async_extent->compress_type;
 774                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 775                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 776                 em->generation = -1;
 777
 778                 while (1) {
 779                         write_lock(&em_tree->lock);
 780                         ret = add_extent_mapping(em_tree, em, 1);
 781                         write_unlock(&em_tree->lock);
 782                         if (ret != -EEXIST) {
 783                                 free_extent_map(em);
 784                                 break;
 785                         }
 786                         btrfs_drop_extent_cache(inode, async_extent->start,
 787                                                 async_extent->start +
 788                                                 async_extent->ram_size - 1, 0);
 789                 }
 790
 791                 if (ret)
 792                         goto out_free_reserve;
 793
 794                 ret = btrfs_add_ordered_extent_compress(inode,
 795                                                 async_extent->start,
 796                                                 ins.objectid,
 797                                                 async_extent->ram_size,
 798                                                 ins.offset,
 799                                                 BTRFS_ORDERED_COMPRESSED,
 800                                                 async_extent->compress_type);
 801                 if (ret) {
 802                         btrfs_drop_extent_cache(inode, async_extent->start,
 803                                                 async_extent->start +
 804                                                 async_extent->ram_size - 1, 0);
 805                         goto out_free_reserve;
 806                 }
 807
 808                 /*
 809                  * clear dirty, set writeback and unlock the pages.
 810                  */
 811                 extent_clear_unlock_delalloc(inode, async_extent->start,
 812                                 async_extent->start +
 813                                 async_extent->ram_size - 1,
 814                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 815                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 816                                 PAGE_SET_WRITEBACK);
 817                 ret = btrfs_submit_compressed_write(inode,
 818                                     async_extent->start,
 819                                     async_extent->ram_size,
 820                                     ins.objectid,
 821                                     ins.offset, async_extent->pages,
 822                                     async_extent->nr_pages);
 823                 if (ret) {
 824                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 825                         struct page *p = async_extent->pages[0];
 826                         const u64 start = async_extent->start;
 827                         const u64 end = start + async_extent->ram_size - 1;
 828
 829                         p->mapping = inode->i_mapping;
 830                         tree->ops->writepage_end_io_hook(p, start, end,
 831                                                          NULL, 0);
 832                         p->mapping = NULL;
 833                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 834                                                      PAGE_END_WRITEBACK |
 835                                                      PAGE_SET_ERROR);
 836                         free_async_extent_pages(async_extent);
 837                 }
 838                 alloc_hint = ins.objectid + ins.offset;
 839                 kfree(async_extent);
 840                 cond_resched();
 841         }
 842         return;
 843 out_free_reserve:
 844         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 845 out_free:
 846         extent_clear_unlock_delalloc(inode, async_extent->start,
 847                                      async_extent->start +
 848                                      async_extent->ram_size - 1,
 849                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 850                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 851                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 852                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 853                                      PAGE_SET_ERROR);
 854         free_async_extent_pages(async_extent);
 855         kfree(async_extent);
 856         goto again;
 857 }
 858
 859 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 860                                       u64 num_bytes)
 861 {
 862         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 863         struct extent_map *em;
 864         u64 alloc_hint = 0;
 865
 866         read_lock(&em_tree->lock);
 867         em = search_extent_mapping(em_tree, start, num_bytes);
 868         if (em) {
 869                 /*
 870                  * if block start isn't an actual block number then find the
 871                  * first block in this inode and use that as a hint.  If that
 872                  * block is also bogus then just don't worry about it.
 873                  */
 874                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 875                         free_extent_map(em);
 876                         em = search_extent_mapping(em_tree, 0, 0);
 877                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 878                                 alloc_hint = em->block_start;
 879                         if (em)
 880                                 free_extent_map(em);
 881                 } else {
 882                         alloc_hint = em->block_start;
 883                         free_extent_map(em);
 884                 }
 885         }
 886         read_unlock(&em_tree->lock);
 887
 888         return alloc_hint;
 889 }
 890
 891 /*
 892  * when extent_io.c finds a delayed allocation range in the file,
 893  * the call backs end up in this code.  The basic idea is to
 894  * allocate extents on disk for the range, and create ordered data structs
 895  * in ram to track those extents.
 896  *
 897  * locked_page is the page that writepage had locked already.  We use
 898  * it to make sure we don't do extra locks or unlocks.
 899  *
 900  * *page_started is set to one if we unlock locked_page and do everything
 901  * required to start IO on it.  It may be clean and already done with
 902  * IO when we return.
 903  */
 904 static noinline int cow_file_range(struct inode *inode,
 905                                    struct page *locked_page,
 906                                    u64 start, u64 end, int *page_started,
 907                                    unsigned long *nr_written,
 908                                    int unlock)
 909 {
 910         struct btrfs_root *root = BTRFS_I(inode)->root;
 911         u64 alloc_hint = 0;
 912         u64 num_bytes;
 913         unsigned long ram_size;
 914         u64 disk_num_bytes;
 915         u64 cur_alloc_size;
 916         u64 blocksize = root->sectorsize;
 917         struct btrfs_key ins;
 918         struct extent_map *em;
 919         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 920         int ret = 0;
 921
 922         if (btrfs_is_free_space_inode(inode)) {
 923                 WARN_ON_ONCE(1);
 924                 ret = -EINVAL;
 925                 goto out_unlock;
 926         }
 927
 928         num_bytes = ALIGN(end - start + 1, blocksize);
 929         num_bytes = max(blocksize,  num_bytes);
 930         disk_num_bytes = num_bytes;
 931
 932         /* if this is a small write inside eof, kick off defrag */
 933         if (num_bytes < 64 * 1024 &&
 934             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 935                 btrfs_add_inode_defrag(NULL, inode);
 936
 937         if (start == 0) {
 938                 /* lets try to make an inline extent */
 939                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 940                                             NULL);
 941                 if (ret == 0) {
 942                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 943                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 944                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 945                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 946                                      PAGE_END_WRITEBACK);
 947
 948                         *nr_written = *nr_written +
 949                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 950                         *page_started = 1;
 951                         goto out;
 952                 } else if (ret < 0) {
 953                         goto out_unlock;
 954                 }
 955         }
 956
 957         BUG_ON(disk_num_bytes >
 958                btrfs_super_total_bytes(root->fs_info->super_copy));
 959
 960         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 961         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 962
 963         while (disk_num_bytes > 0) {
 964                 unsigned long op;
 965
 966                 cur_alloc_size = disk_num_bytes;
 967                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 968                                            root->sectorsize, 0, alloc_hint,
 969                                            &ins, 1, 1);
 970                 if (ret < 0)
 971                         goto out_unlock;
 972
 973                 em = alloc_extent_map();
 974                 if (!em) {
 975                         ret = -ENOMEM;
 976                         goto out_reserve;
 977                 }
 978                 em->start = start;
 979                 em->orig_start = em->start;
 980                 ram_size = ins.offset;
 981                 em->len = ins.offset;
 982                 em->mod_start = em->start;
 983                 em->mod_len = em->len;
 984
 985                 em->block_start = ins.objectid;
 986                 em->block_len = ins.offset;
 987                 em->orig_block_len = ins.offset;
 988                 em->ram_bytes = ram_size;
 989                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 990                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 991                 em->generation = -1;
 992
 993                 while (1) {
 994                         write_lock(&em_tree->lock);
 995                         ret = add_extent_mapping(em_tree, em, 1);
 996                         write_unlock(&em_tree->lock);
 997                         if (ret != -EEXIST) {
 998                                 free_extent_map(em);
 999                                 break;
1000                         }
1001                         btrfs_drop_extent_cache(inode, start,
1002                                                 start + ram_size - 1, 0);
1003                 }
1004                 if (ret)
1005                         goto out_reserve;
1006
1007                 cur_alloc_size = ins.offset;
1008                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1009                                                ram_size, cur_alloc_size, 0);
1010                 if (ret)
1011                         goto out_drop_extent_cache;
1012
1013                 if (root->root_key.objectid ==
1014                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1015                         ret = btrfs_reloc_clone_csums(inode, start,
1016                                                       cur_alloc_size);
1017                         if (ret)
1018                                 goto out_drop_extent_cache;
1019                 }
1020
1021                 if (disk_num_bytes < cur_alloc_size)
1022                         break;
1023
1024                 /* we're not doing compressed IO, don't unlock the first
1025                  * page (which the caller expects to stay locked), don't
1026                  * clear any dirty bits and don't set any writeback bits
1027                  *
1028                  * Do set the Private2 bit so we know this page was properly
1029                  * setup for writepage
1030                  */
1031                 op = unlock ? PAGE_UNLOCK : 0;
1032                 op |= PAGE_SET_PRIVATE2;
1033
1034                 extent_clear_unlock_delalloc(inode, start,
1035                                              start + ram_size - 1, locked_page,
1036                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1037                                              op);
1038                 disk_num_bytes -= cur_alloc_size;
1039                 num_bytes -= cur_alloc_size;
1040                 alloc_hint = ins.objectid + ins.offset;
1041                 start += cur_alloc_size;
1042         }
1043 out:
1044         return ret;
1045
1046 out_drop_extent_cache:
1047         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1048 out_reserve:
1049         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1050 out_unlock:
1051         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1052                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1053                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1054                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1055                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1056         goto out;
1057 }
1058
1059 /*
1060  * work queue call back to started compression on a file and pages
1061  */
1062 static noinline void async_cow_start(struct btrfs_work *work)
1063 {
1064         struct async_cow *async_cow;
1065         int num_added = 0;
1066         async_cow = container_of(work, struct async_cow, work);
1067
1068         compress_file_range(async_cow->inode, async_cow->locked_page,
1069                             async_cow->start, async_cow->end, async_cow,
1070                             &num_added);
1071         if (num_added == 0) {
1072                 btrfs_add_delayed_iput(async_cow->inode);
1073                 async_cow->inode = NULL;
1074         }
1075 }
1076
1077 /*
1078  * work queue call back to submit previously compressed pages
1079  */
1080 static noinline void async_cow_submit(struct btrfs_work *work)
1081 {
1082         struct async_cow *async_cow;
1083         struct btrfs_root *root;
1084         unsigned long nr_pages;
1085
1086         async_cow = container_of(work, struct async_cow, work);
1087
1088         root = async_cow->root;
1089         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1090                 PAGE_CACHE_SHIFT;
1091
1092         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1093             5 * 1024 * 1024 &&
1094             waitqueue_active(&root->fs_info->async_submit_wait))
1095                 wake_up(&root->fs_info->async_submit_wait);
1096
1097         if (async_cow->inode)
1098                 submit_compressed_extents(async_cow->inode, async_cow);
1099 }
1100
1101 static noinline void async_cow_free(struct btrfs_work *work)
1102 {
1103         struct async_cow *async_cow;
1104         async_cow = container_of(work, struct async_cow, work);
1105         if (async_cow->inode)
1106                 btrfs_add_delayed_iput(async_cow->inode);
1107         kfree(async_cow);
1108 }
1109
1110 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1111                                 u64 start, u64 end, int *page_started,
1112                                 unsigned long *nr_written)
1113 {
1114         struct async_cow *async_cow;
1115         struct btrfs_root *root = BTRFS_I(inode)->root;
1116         unsigned long nr_pages;
1117         u64 cur_end;
1118         int limit = 10 * 1024 * 1024;
1119
1120         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1121                          1, 0, NULL, GFP_NOFS);
1122         while (start < end) {
1123                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1124                 BUG_ON(!async_cow); /* -ENOMEM */
1125                 async_cow->inode = igrab(inode);
1126                 async_cow->root = root;
1127                 async_cow->locked_page = locked_page;
1128                 async_cow->start = start;
1129
1130                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1131                     !btrfs_test_opt(root, FORCE_COMPRESS))
1132                         cur_end = end;
1133                 else
1134                         cur_end = min(end, start + 512 * 1024 - 1);
1135
1136                 async_cow->end = cur_end;
1137                 INIT_LIST_HEAD(&async_cow->extents);
1138
1139                 btrfs_init_work(&async_cow->work,
1140                                 btrfs_delalloc_helper,
1141                                 async_cow_start, async_cow_submit,
1142                                 async_cow_free);
1143
1144                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1145                         PAGE_CACHE_SHIFT;
1146                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1147
1148                 btrfs_queue_work(root->fs_info->delalloc_workers,
1149                                  &async_cow->work);
1150
1151                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1152                         wait_event(root->fs_info->async_submit_wait,
1153                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1154                             limit));
1155                 }
1156
1157                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1158                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1159                         wait_event(root->fs_info->async_submit_wait,
1160                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1161                            0));
1162                 }
1163
1164                 *nr_written += nr_pages;
1165                 start = cur_end + 1;
1166         }
1167         *page_started = 1;
1168         return 0;
1169 }
1170
1171 static noinline int csum_exist_in_range(struct btrfs_root *root,
1172                                         u64 bytenr, u64 num_bytes)
1173 {
1174         int ret;
1175         struct btrfs_ordered_sum *sums;
1176         LIST_HEAD(list);
1177
1178         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1179                                        bytenr + num_bytes - 1, &list, 0);
1180         if (ret == 0 && list_empty(&list))
1181                 return 0;
1182
1183         while (!list_empty(&list)) {
1184                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1185                 list_del(&sums->list);
1186                 kfree(sums);
1187         }
1188         return 1;
1189 }
1190
1191 /*
1192  * when nowcow writeback call back.  This checks for snapshots or COW copies
1193  * of the extents that exist in the file, and COWs the file as required.
1194  *
1195  * If no cow copies or snapshots exist, we write directly to the existing
1196  * blocks on disk
1197  */
1198 static noinline int run_delalloc_nocow(struct inode *inode,
1199                                        struct page *locked_page,
1200                               u64 start, u64 end, int *page_started, int force,
1201                               unsigned long *nr_written)
1202 {
1203         struct btrfs_root *root = BTRFS_I(inode)->root;
1204         struct btrfs_trans_handle *trans;
1205         struct extent_buffer *leaf;
1206         struct btrfs_path *path;
1207         struct btrfs_file_extent_item *fi;
1208         struct btrfs_key found_key;
1209         u64 cow_start;
1210         u64 cur_offset;
1211         u64 extent_end;
1212         u64 extent_offset;
1213         u64 disk_bytenr;
1214         u64 num_bytes;
1215         u64 disk_num_bytes;
1216         u64 ram_bytes;
1217         int extent_type;
1218         int ret, err;
1219         int type;
1220         int nocow;
1221         int check_prev = 1;
1222         bool nolock;
1223         u64 ino = btrfs_ino(inode);
1224
1225         path = btrfs_alloc_path();
1226         if (!path) {
1227                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1228                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1229                                              EXTENT_DO_ACCOUNTING |
1230                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1231                                              PAGE_CLEAR_DIRTY |
1232                                              PAGE_SET_WRITEBACK |
1233                                              PAGE_END_WRITEBACK);
1234                 return -ENOMEM;
1235         }
1236
1237         nolock = btrfs_is_free_space_inode(inode);
1238
1239         if (nolock)
1240                 trans = btrfs_join_transaction_nolock(root);
1241         else
1242                 trans = btrfs_join_transaction(root);
1243
1244         if (IS_ERR(trans)) {
1245                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1246                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1247                                              EXTENT_DO_ACCOUNTING |
1248                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1249                                              PAGE_CLEAR_DIRTY |
1250                                              PAGE_SET_WRITEBACK |
1251                                              PAGE_END_WRITEBACK);
1252                 btrfs_free_path(path);
1253                 return PTR_ERR(trans);
1254         }
1255
1256         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1257
1258         cow_start = (u64)-1;
1259         cur_offset = start;
1260         while (1) {
1261                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1262                                                cur_offset, 0);
1263                 if (ret < 0)
1264                         goto error;
1265                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1266                         leaf = path->nodes[0];
1267                         btrfs_item_key_to_cpu(leaf, &found_key,
1268                                               path->slots[0] - 1);
1269                         if (found_key.objectid == ino &&
1270                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1271                                 path->slots[0]--;
1272                 }
1273                 check_prev = 0;
1274 next_slot:
1275                 leaf = path->nodes[0];
1276                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1277                         ret = btrfs_next_leaf(root, path);
1278                         if (ret < 0)
1279                                 goto error;
1280                         if (ret > 0)
1281                                 break;
1282                         leaf = path->nodes[0];
1283                 }
1284
1285                 nocow = 0;
1286                 disk_bytenr = 0;
1287                 num_bytes = 0;
1288                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1289
1290                 if (found_key.objectid > ino ||
1291                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1292                     found_key.offset > end)
1293                         break;
1294
1295                 if (found_key.offset > cur_offset) {
1296                         extent_end = found_key.offset;
1297                         extent_type = 0;
1298                         goto out_check;
1299                 }
1300
1301                 fi = btrfs_item_ptr(leaf, path->slots[0],
1302                                     struct btrfs_file_extent_item);
1303                 extent_type = btrfs_file_extent_type(leaf, fi);
1304
1305                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1306                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1307                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1308                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1309                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1310                         extent_end = found_key.offset +
1311                                 btrfs_file_extent_num_bytes(leaf, fi);
1312                         disk_num_bytes =
1313                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1314                         if (extent_end <= start) {
1315                                 path->slots[0]++;
1316                                 goto next_slot;
1317                         }
1318                         if (disk_bytenr == 0)
1319                                 goto out_check;
1320                         if (btrfs_file_extent_compression(leaf, fi) ||
1321                             btrfs_file_extent_encryption(leaf, fi) ||
1322                             btrfs_file_extent_other_encoding(leaf, fi))
1323                                 goto out_check;
1324                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1325                                 goto out_check;
1326                         if (btrfs_extent_readonly(root, disk_bytenr))
1327                                 goto out_check;
1328                         if (btrfs_cross_ref_exist(trans, root, ino,
1329                                                   found_key.offset -
1330                                                   extent_offset, disk_bytenr))
1331                                 goto out_check;
1332                         disk_bytenr += extent_offset;
1333                         disk_bytenr += cur_offset - found_key.offset;
1334                         num_bytes = min(end + 1, extent_end) - cur_offset;
1335                         /*
1336                          * if there are pending snapshots for this root,
1337                          * we fall into common COW way.
1338                          */
1339                         if (!nolock) {
1340                                 err = btrfs_start_nocow_write(root);
1341                                 if (!err)
1342                                         goto out_check;
1343                         }
1344                         /*
1345                          * force cow if csum exists in the range.
1346                          * this ensure that csum for a given extent are
1347                          * either valid or do not exist.
1348                          */
1349                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1350                                 goto out_check;
1351                         nocow = 1;
1352                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1353                         extent_end = found_key.offset +
1354                                 btrfs_file_extent_inline_len(leaf,
1355                                                      path->slots[0], fi);
1356                         extent_end = ALIGN(extent_end, root->sectorsize);
1357                 } else {
1358                         BUG_ON(1);
1359                 }
1360 out_check:
1361                 if (extent_end <= start) {
1362                         path->slots[0]++;
1363                         if (!nolock && nocow)
1364                                 btrfs_end_nocow_write(root);
1365                         goto next_slot;
1366                 }
1367                 if (!nocow) {
1368                         if (cow_start == (u64)-1)
1369                                 cow_start = cur_offset;
1370                         cur_offset = extent_end;
1371                         if (cur_offset > end)
1372                                 break;
1373                         path->slots[0]++;
1374                         goto next_slot;
1375                 }
1376
1377                 btrfs_release_path(path);
1378                 if (cow_start != (u64)-1) {
1379                         ret = cow_file_range(inode, locked_page,
1380                                              cow_start, found_key.offset - 1,
1381                                              page_started, nr_written, 1);
1382                         if (ret) {
1383                                 if (!nolock && nocow)
1384                                         btrfs_end_nocow_write(root);
1385                                 goto error;
1386                         }
1387                         cow_start = (u64)-1;
1388                 }
1389
1390                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1391                         struct extent_map *em;
1392                         struct extent_map_tree *em_tree;
1393                         em_tree = &BTRFS_I(inode)->extent_tree;
1394                         em = alloc_extent_map();
1395                         BUG_ON(!em); /* -ENOMEM */
1396                         em->start = cur_offset;
1397                         em->orig_start = found_key.offset - extent_offset;
1398                         em->len = num_bytes;
1399                         em->block_len = num_bytes;
1400                         em->block_start = disk_bytenr;
1401                         em->orig_block_len = disk_num_bytes;
1402                         em->ram_bytes = ram_bytes;
1403                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1404                         em->mod_start = em->start;
1405                         em->mod_len = em->len;
1406                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1407                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1408                         em->generation = -1;
1409                         while (1) {
1410                                 write_lock(&em_tree->lock);
1411                                 ret = add_extent_mapping(em_tree, em, 1);
1412                                 write_unlock(&em_tree->lock);
1413                                 if (ret != -EEXIST) {
1414                                         free_extent_map(em);
1415                                         break;
1416                                 }
1417                                 btrfs_drop_extent_cache(inode, em->start,
1418                                                 em->start + em->len - 1, 0);
1419                         }
1420                         type = BTRFS_ORDERED_PREALLOC;
1421                 } else {
1422                         type = BTRFS_ORDERED_NOCOW;
1423                 }
1424
1425                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1426                                                num_bytes, num_bytes, type);
1427                 BUG_ON(ret); /* -ENOMEM */
1428
1429                 if (root->root_key.objectid ==
1430                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1431                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1432                                                       num_bytes);
1433                         if (ret) {
1434                                 if (!nolock && nocow)
1435                                         btrfs_end_nocow_write(root);
1436                                 goto error;
1437                         }
1438                 }
1439
1440                 extent_clear_unlock_delalloc(inode, cur_offset,
1441                                              cur_offset + num_bytes - 1,
1442                                              locked_page, EXTENT_LOCKED |
1443                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1444                                              PAGE_SET_PRIVATE2);
1445                 if (!nolock && nocow)
1446                         btrfs_end_nocow_write(root);
1447                 cur_offset = extent_end;
1448                 if (cur_offset > end)
1449                         break;
1450         }
1451         btrfs_release_path(path);
1452
1453         if (cur_offset <= end && cow_start == (u64)-1) {
1454                 cow_start = cur_offset;
1455                 cur_offset = end;
1456         }
1457
1458         if (cow_start != (u64)-1) {
1459                 ret = cow_file_range(inode, locked_page, cow_start, end,
1460                                      page_started, nr_written, 1);
1461                 if (ret)
1462                         goto error;
1463         }
1464
1465 error:
1466         err = btrfs_end_transaction(trans, root);
1467         if (!ret)
1468                 ret = err;
1469
1470         if (ret && cur_offset < end)
1471                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1472                                              locked_page, EXTENT_LOCKED |
1473                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1474                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1475                                              PAGE_CLEAR_DIRTY |
1476                                              PAGE_SET_WRITEBACK |
1477                                              PAGE_END_WRITEBACK);
1478         btrfs_free_path(path);
1479         return ret;
1480 }
1481
1482 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1483 {
1484
1485         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1486             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1487                 return 0;
1488
1489         /*
1490          * @defrag_bytes is a hint value, no spinlock held here,
1491          * if is not zero, it means the file is defragging.
1492          * Force cow if given extent needs to be defragged.
1493          */
1494         if (BTRFS_I(inode)->defrag_bytes &&
1495             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1496                            EXTENT_DEFRAG, 0, NULL))
1497                 return 1;
1498
1499         return 0;
1500 }
1501
1502 /*
1503  * extent_io.c call back to do delayed allocation processing
1504  */
1505 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1506                               u64 start, u64 end, int *page_started,
1507                               unsigned long *nr_written)
1508 {
1509         int ret;
1510         int force_cow = need_force_cow(inode, start, end);
1511
1512         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1513                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1514                                          page_started, 1, nr_written);
1515         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1516                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1517                                          page_started, 0, nr_written);
1518         } else if (!inode_need_compress(inode)) {
1519                 ret = cow_file_range(inode, locked_page, start, end,
1520                                       page_started, nr_written, 1);
1521         } else {
1522                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1523                         &BTRFS_I(inode)->runtime_flags);
1524                 ret = cow_file_range_async(inode, locked_page, start, end,
1525                                            page_started, nr_written);
1526         }
1527         return ret;
1528 }
1529
1530 static void btrfs_split_extent_hook(struct inode *inode,
1531                                     struct extent_state *orig, u64 split)
1532 {
1533         /* not delalloc, ignore it */
1534         if (!(orig->state & EXTENT_DELALLOC))
1535                 return;
1536
1537         spin_lock(&BTRFS_I(inode)->lock);
1538         BTRFS_I(inode)->outstanding_extents++;
1539         spin_unlock(&BTRFS_I(inode)->lock);
1540 }
1541
1542 /*
1543  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1544  * extents so we can keep track of new extents that are just merged onto old
1545  * extents, such as when we are doing sequential writes, so we can properly
1546  * account for the metadata space we'll need.
1547  */
1548 static void btrfs_merge_extent_hook(struct inode *inode,
1549                                     struct extent_state *new,
1550                                     struct extent_state *other)
1551 {
1552         /* not delalloc, ignore it */
1553         if (!(other->state & EXTENT_DELALLOC))
1554                 return;
1555
1556         spin_lock(&BTRFS_I(inode)->lock);
1557         BTRFS_I(inode)->outstanding_extents--;
1558         spin_unlock(&BTRFS_I(inode)->lock);
1559 }
1560
1561 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1562                                       struct inode *inode)
1563 {
1564         spin_lock(&root->delalloc_lock);
1565         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1566                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1567                               &root->delalloc_inodes);
1568                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1569                         &BTRFS_I(inode)->runtime_flags);
1570                 root->nr_delalloc_inodes++;
1571                 if (root->nr_delalloc_inodes == 1) {
1572                         spin_lock(&root->fs_info->delalloc_root_lock);
1573                         BUG_ON(!list_empty(&root->delalloc_root));
1574                         list_add_tail(&root->delalloc_root,
1575                                       &root->fs_info->delalloc_roots);
1576                         spin_unlock(&root->fs_info->delalloc_root_lock);
1577                 }
1578         }
1579         spin_unlock(&root->delalloc_lock);
1580 }
1581
1582 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1583                                      struct inode *inode)
1584 {
1585         spin_lock(&root->delalloc_lock);
1586         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1587                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1588                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1589                           &BTRFS_I(inode)->runtime_flags);
1590                 root->nr_delalloc_inodes--;
1591                 if (!root->nr_delalloc_inodes) {
1592                         spin_lock(&root->fs_info->delalloc_root_lock);
1593                         BUG_ON(list_empty(&root->delalloc_root));
1594                         list_del_init(&root->delalloc_root);
1595                         spin_unlock(&root->fs_info->delalloc_root_lock);
1596                 }
1597         }
1598         spin_unlock(&root->delalloc_lock);
1599 }
1600
1601 /*
1602  * extent_io.c set_bit_hook, used to track delayed allocation
1603  * bytes in this file, and to maintain the list of inodes that
1604  * have pending delalloc work to be done.
1605  */
1606 static void btrfs_set_bit_hook(struct inode *inode,
1607                                struct extent_state *state, unsigned long *bits)
1608 {
1609
1610         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1611                 WARN_ON(1);
1612         /*
1613          * set_bit and clear bit hooks normally require _irqsave/restore
1614          * but in this case, we are only testing for the DELALLOC
1615          * bit, which is only set or cleared with irqs on
1616          */
1617         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1618                 struct btrfs_root *root = BTRFS_I(inode)->root;
1619                 u64 len = state->end + 1 - state->start;
1620                 bool do_list = !btrfs_is_free_space_inode(inode);
1621
1622                 if (*bits & EXTENT_FIRST_DELALLOC) {
1623                         *bits &= ~EXTENT_FIRST_DELALLOC;
1624                 } else {
1625                         spin_lock(&BTRFS_I(inode)->lock);
1626                         BTRFS_I(inode)->outstanding_extents++;
1627                         spin_unlock(&BTRFS_I(inode)->lock);
1628                 }
1629
1630                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1631                                      root->fs_info->delalloc_batch);
1632                 spin_lock(&BTRFS_I(inode)->lock);
1633                 BTRFS_I(inode)->delalloc_bytes += len;
1634                 if (*bits & EXTENT_DEFRAG)
1635                         BTRFS_I(inode)->defrag_bytes += len;
1636                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1637                                          &BTRFS_I(inode)->runtime_flags))
1638                         btrfs_add_delalloc_inodes(root, inode);
1639                 spin_unlock(&BTRFS_I(inode)->lock);
1640         }
1641 }
1642
1643 /*
1644  * extent_io.c clear_bit_hook, see set_bit_hook for why
1645  */
1646 static void btrfs_clear_bit_hook(struct inode *inode,
1647                                  struct extent_state *state,
1648                                  unsigned long *bits)
1649 {
1650         u64 len = state->end + 1 - state->start;
1651
1652         spin_lock(&BTRFS_I(inode)->lock);
1653         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1654                 BTRFS_I(inode)->defrag_bytes -= len;
1655         spin_unlock(&BTRFS_I(inode)->lock);
1656
1657         /*
1658          * set_bit and clear bit hooks normally require _irqsave/restore
1659          * but in this case, we are only testing for the DELALLOC
1660          * bit, which is only set or cleared with irqs on
1661          */
1662         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1663                 struct btrfs_root *root = BTRFS_I(inode)->root;
1664                 bool do_list = !btrfs_is_free_space_inode(inode);
1665
1666                 if (*bits & EXTENT_FIRST_DELALLOC) {
1667                         *bits &= ~EXTENT_FIRST_DELALLOC;
1668                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1669                         spin_lock(&BTRFS_I(inode)->lock);
1670                         BTRFS_I(inode)->outstanding_extents--;
1671                         spin_unlock(&BTRFS_I(inode)->lock);
1672                 }
1673
1674                 /*
1675                  * We don't reserve metadata space for space cache inodes so we
1676                  * don't need to call dellalloc_release_metadata if there is an
1677                  * error.
1678                  */
1679                 if (*bits & EXTENT_DO_ACCOUNTING &&
1680                     root != root->fs_info->tree_root)
1681                         btrfs_delalloc_release_metadata(inode, len);
1682
1683                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1684                     && do_list && !(state->state & EXTENT_NORESERVE))
1685                         btrfs_free_reserved_data_space(inode, len);
1686
1687                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1688                                      root->fs_info->delalloc_batch);
1689                 spin_lock(&BTRFS_I(inode)->lock);
1690                 BTRFS_I(inode)->delalloc_bytes -= len;
1691                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1692                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1693                              &BTRFS_I(inode)->runtime_flags))
1694                         btrfs_del_delalloc_inode(root, inode);
1695                 spin_unlock(&BTRFS_I(inode)->lock);
1696         }
1697 }
1698
1699 /*
1700  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1701  * we don't create bios that span stripes or chunks
1702  */
1703 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1704                          size_t size, struct bio *bio,
1705                          unsigned long bio_flags)
1706 {
1707         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1708         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1709         u64 length = 0;
1710         u64 map_length;
1711         int ret;
1712
1713         if (bio_flags & EXTENT_BIO_COMPRESSED)
1714                 return 0;
1715
1716         length = bio->bi_iter.bi_size;
1717         map_length = length;
1718         ret = btrfs_map_block(root->fs_info, rw, logical,
1719                               &map_length, NULL, 0);
1720         /* Will always return 0 with map_multi == NULL */
1721         BUG_ON(ret < 0);
1722         if (map_length < length + size)
1723                 return 1;
1724         return 0;
1725 }
1726
1727 /*
1728  * in order to insert checksums into the metadata in large chunks,
1729  * we wait until bio submission time.   All the pages in the bio are
1730  * checksummed and sums are attached onto the ordered extent record.
1731  *
1732  * At IO completion time the cums attached on the ordered extent record
1733  * are inserted into the btree
1734  */
1735 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1736                                     struct bio *bio, int mirror_num,
1737                                     unsigned long bio_flags,
1738                                     u64 bio_offset)
1739 {
1740         struct btrfs_root *root = BTRFS_I(inode)->root;
1741         int ret = 0;
1742
1743         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1744         BUG_ON(ret); /* -ENOMEM */
1745         return 0;
1746 }
1747
1748 /*
1749  * in order to insert checksums into the metadata in large chunks,
1750  * we wait until bio submission time.   All the pages in the bio are
1751  * checksummed and sums are attached onto the ordered extent record.
1752  *
1753  * At IO completion time the cums attached on the ordered extent record
1754  * are inserted into the btree
1755  */
1756 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1757                           int mirror_num, unsigned long bio_flags,
1758                           u64 bio_offset)
1759 {
1760         struct btrfs_root *root = BTRFS_I(inode)->root;
1761         int ret;
1762
1763         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1764         if (ret)
1765                 bio_endio(bio, ret);
1766         return ret;
1767 }
1768
1769 /*
1770  * extent_io.c submission hook. This does the right thing for csum calculation
1771  * on write, or reading the csums from the tree before a read
1772  */
1773 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1774                           int mirror_num, unsigned long bio_flags,
1775                           u64 bio_offset)
1776 {
1777         struct btrfs_root *root = BTRFS_I(inode)->root;
1778         int ret = 0;
1779         int skip_sum;
1780         int metadata = 0;
1781         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1782
1783         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1784
1785         if (btrfs_is_free_space_inode(inode))
1786                 metadata = 2;
1787
1788         if (!(rw & REQ_WRITE)) {
1789                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1790                 if (ret)
1791                         goto out;
1792
1793                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1794                         ret = btrfs_submit_compressed_read(inode, bio,
1795                                                            mirror_num,
1796                                                            bio_flags);
1797                         goto out;
1798                 } else if (!skip_sum) {
1799                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1800                         if (ret)
1801                                 goto out;
1802                 }
1803                 goto mapit;
1804         } else if (async && !skip_sum) {
1805                 /* csum items have already been cloned */
1806                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1807                         goto mapit;
1808                 /* we're doing a write, do the async checksumming */
1809                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1810                                    inode, rw, bio, mirror_num,
1811                                    bio_flags, bio_offset,
1812                                    __btrfs_submit_bio_start,
1813                                    __btrfs_submit_bio_done);
1814                 goto out;
1815         } else if (!skip_sum) {
1816                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1817                 if (ret)
1818                         goto out;
1819         }
1820
1821 mapit:
1822         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1823
1824 out:
1825         if (ret < 0)
1826                 bio_endio(bio, ret);
1827         return ret;
1828 }
1829
1830 /*
1831  * given a list of ordered sums record them in the inode.  This happens
1832  * at IO completion time based on sums calculated at bio submission time.
1833  */
1834 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1835                              struct inode *inode, u64 file_offset,
1836                              struct list_head *list)
1837 {
1838         struct btrfs_ordered_sum *sum;
1839
1840         list_for_each_entry(sum, list, list) {
1841                 trans->adding_csums = 1;
1842                 btrfs_csum_file_blocks(trans,
1843                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1844                 trans->adding_csums = 0;
1845         }
1846         return 0;
1847 }
1848
1849 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1850                               struct extent_state **cached_state)
1851 {
1852         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1853         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1854                                    cached_state, GFP_NOFS);
1855 }
1856
1857 /* see btrfs_writepage_start_hook for details on why this is required */
1858 struct btrfs_writepage_fixup {
1859         struct page *page;
1860         struct btrfs_work work;
1861 };
1862
1863 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1864 {
1865         struct btrfs_writepage_fixup *fixup;
1866         struct btrfs_ordered_extent *ordered;
1867         struct extent_state *cached_state = NULL;
1868         struct page *page;
1869         struct inode *inode;
1870         u64 page_start;
1871         u64 page_end;
1872         int ret;
1873
1874         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1875         page = fixup->page;
1876 again:
1877         lock_page(page);
1878         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1879                 ClearPageChecked(page);
1880                 goto out_page;
1881         }
1882
1883         inode = page->mapping->host;
1884         page_start = page_offset(page);
1885         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1886
1887         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1888                          &cached_state);
1889
1890         /* already ordered? We're done */
1891         if (PagePrivate2(page))
1892                 goto out;
1893
1894         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1895         if (ordered) {
1896                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1897                                      page_end, &cached_state, GFP_NOFS);
1898                 unlock_page(page);
1899                 btrfs_start_ordered_extent(inode, ordered, 1);
1900                 btrfs_put_ordered_extent(ordered);
1901                 goto again;
1902         }
1903
1904         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1905         if (ret) {
1906                 mapping_set_error(page->mapping, ret);
1907                 end_extent_writepage(page, ret, page_start, page_end);
1908                 ClearPageChecked(page);
1909                 goto out;
1910          }
1911
1912         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1913         ClearPageChecked(page);
1914         set_page_dirty(page);
1915 out:
1916         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1917                              &cached_state, GFP_NOFS);
1918 out_page:
1919         unlock_page(page);
1920         page_cache_release(page);
1921         kfree(fixup);
1922 }
1923
1924 /*
1925  * There are a few paths in the higher layers of the kernel that directly
1926  * set the page dirty bit without asking the filesystem if it is a
1927  * good idea.  This causes problems because we want to make sure COW
1928  * properly happens and the data=ordered rules are followed.
1929  *
1930  * In our case any range that doesn't have the ORDERED bit set
1931  * hasn't been properly setup for IO.  We kick off an async process
1932  * to fix it up.  The async helper will wait for ordered extents, set
1933  * the delalloc bit and make it safe to write the page.
1934  */
1935 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1936 {
1937         struct inode *inode = page->mapping->host;
1938         struct btrfs_writepage_fixup *fixup;
1939         struct btrfs_root *root = BTRFS_I(inode)->root;
1940
1941         /* this page is properly in the ordered list */
1942         if (TestClearPagePrivate2(page))
1943                 return 0;
1944
1945         if (PageChecked(page))
1946                 return -EAGAIN;
1947
1948         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1949         if (!fixup)
1950                 return -EAGAIN;
1951
1952         SetPageChecked(page);
1953         page_cache_get(page);
1954         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
1955                         btrfs_writepage_fixup_worker, NULL, NULL);
1956         fixup->page = page;
1957         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1958         return -EBUSY;
1959 }
1960
1961 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1962                                        struct inode *inode, u64 file_pos,
1963                                        u64 disk_bytenr, u64 disk_num_bytes,
1964                                        u64 num_bytes, u64 ram_bytes,
1965                                        u8 compression, u8 encryption,
1966                                        u16 other_encoding, int extent_type)
1967 {
1968         struct btrfs_root *root = BTRFS_I(inode)->root;
1969         struct btrfs_file_extent_item *fi;
1970         struct btrfs_path *path;
1971         struct extent_buffer *leaf;
1972         struct btrfs_key ins;
1973         int extent_inserted = 0;
1974         int ret;
1975
1976         path = btrfs_alloc_path();
1977         if (!path)
1978                 return -ENOMEM;
1979
1980         /*
1981          * we may be replacing one extent in the tree with another.
1982          * The new extent is pinned in the extent map, and we don't want
1983          * to drop it from the cache until it is completely in the btree.
1984          *
1985          * So, tell btrfs_drop_extents to leave this extent in the cache.
1986          * the caller is expected to unpin it and allow it to be merged
1987          * with the others.
1988          */
1989         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1990                                    file_pos + num_bytes, NULL, 0,
1991                                    1, sizeof(*fi), &extent_inserted);
1992         if (ret)
1993                 goto out;
1994
1995         if (!extent_inserted) {
1996                 ins.objectid = btrfs_ino(inode);
1997                 ins.offset = file_pos;
1998                 ins.type = BTRFS_EXTENT_DATA_KEY;
1999
2000                 path->leave_spinning = 1;
2001                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2002                                               sizeof(*fi));
2003                 if (ret)
2004                         goto out;
2005         }
2006         leaf = path->nodes[0];
2007         fi = btrfs_item_ptr(leaf, path->slots[0],
2008                             struct btrfs_file_extent_item);
2009         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2010         btrfs_set_file_extent_type(leaf, fi, extent_type);
2011         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2012         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2013         btrfs_set_file_extent_offset(leaf, fi, 0);
2014         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2015         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2016         btrfs_set_file_extent_compression(leaf, fi, compression);
2017         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2018         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2019
2020         btrfs_mark_buffer_dirty(leaf);
2021         btrfs_release_path(path);
2022
2023         inode_add_bytes(inode, num_bytes);
2024
2025         ins.objectid = disk_bytenr;
2026         ins.offset = disk_num_bytes;
2027         ins.type = BTRFS_EXTENT_ITEM_KEY;
2028         ret = btrfs_alloc_reserved_file_extent(trans, root,
2029                                         root->root_key.objectid,
2030                                         btrfs_ino(inode), file_pos, &ins);
2031 out:
2032         btrfs_free_path(path);
2033
2034         return ret;
2035 }
2036
2037 /* snapshot-aware defrag */
2038 struct sa_defrag_extent_backref {
2039         struct rb_node node;
2040         struct old_sa_defrag_extent *old;
2041         u64 root_id;
2042         u64 inum;
2043         u64 file_pos;
2044         u64 extent_offset;
2045         u64 num_bytes;
2046         u64 generation;
2047 };
2048
2049 struct old_sa_defrag_extent {
2050         struct list_head list;
2051         struct new_sa_defrag_extent *new;
2052
2053         u64 extent_offset;
2054         u64 bytenr;
2055         u64 offset;
2056         u64 len;
2057         int count;
2058 };
2059
2060 struct new_sa_defrag_extent {
2061         struct rb_root root;
2062         struct list_head head;
2063         struct btrfs_path *path;
2064         struct inode *inode;
2065         u64 file_pos;
2066         u64 len;
2067         u64 bytenr;
2068         u64 disk_len;
2069         u8 compress_type;
2070 };
2071
2072 static int backref_comp(struct sa_defrag_extent_backref *b1,
2073                         struct sa_defrag_extent_backref *b2)
2074 {
2075         if (b1->root_id < b2->root_id)
2076                 return -1;
2077         else if (b1->root_id > b2->root_id)
2078                 return 1;
2079
2080         if (b1->inum < b2->inum)
2081                 return -1;
2082         else if (b1->inum > b2->inum)
2083                 return 1;
2084
2085         if (b1->file_pos < b2->file_pos)
2086                 return -1;
2087         else if (b1->file_pos > b2->file_pos)
2088                 return 1;
2089
2090         /*
2091          * [------------------------------] ===> (a range of space)
2092          *     |<--->|   |<---->| =============> (fs/file tree A)
2093          * |<---------------------------->| ===> (fs/file tree B)
2094          *
2095          * A range of space can refer to two file extents in one tree while
2096          * refer to only one file extent in another tree.
2097          *
2098          * So we may process a disk offset more than one time(two extents in A)
2099          * and locate at the same extent(one extent in B), then insert two same
2100          * backrefs(both refer to the extent in B).
2101          */
2102         return 0;
2103 }
2104
2105 static void backref_insert(struct rb_root *root,
2106                            struct sa_defrag_extent_backref *backref)
2107 {
2108         struct rb_node **p = &root->rb_node;
2109         struct rb_node *parent = NULL;
2110         struct sa_defrag_extent_backref *entry;
2111         int ret;
2112
2113         while (*p) {
2114                 parent = *p;
2115                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2116
2117                 ret = backref_comp(backref, entry);
2118                 if (ret < 0)
2119                         p = &(*p)->rb_left;
2120                 else
2121                         p = &(*p)->rb_right;
2122         }
2123
2124         rb_link_node(&backref->node, parent, p);
2125         rb_insert_color(&backref->node, root);
2126 }
2127
2128 /*
2129  * Note the backref might has changed, and in this case we just return 0.
2130  */
2131 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2132                                        void *ctx)
2133 {
2134         struct btrfs_file_extent_item *extent;
2135         struct btrfs_fs_info *fs_info;
2136         struct old_sa_defrag_extent *old = ctx;
2137         struct new_sa_defrag_extent *new = old->new;
2138         struct btrfs_path *path = new->path;
2139         struct btrfs_key key;
2140         struct btrfs_root *root;
2141         struct sa_defrag_extent_backref *backref;
2142         struct extent_buffer *leaf;
2143         struct inode *inode = new->inode;
2144         int slot;
2145         int ret;
2146         u64 extent_offset;
2147         u64 num_bytes;
2148
2149         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2150             inum == btrfs_ino(inode))
2151                 return 0;
2152
2153         key.objectid = root_id;
2154         key.type = BTRFS_ROOT_ITEM_KEY;
2155         key.offset = (u64)-1;
2156
2157         fs_info = BTRFS_I(inode)->root->fs_info;
2158         root = btrfs_read_fs_root_no_name(fs_info, &key);
2159         if (IS_ERR(root)) {
2160                 if (PTR_ERR(root) == -ENOENT)
2161                         return 0;
2162                 WARN_ON(1);
2163                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2164                          inum, offset, root_id);
2165                 return PTR_ERR(root);
2166         }
2167
2168         key.objectid = inum;
2169         key.type = BTRFS_EXTENT_DATA_KEY;
2170         if (offset > (u64)-1 << 32)
2171                 key.offset = 0;
2172         else
2173                 key.offset = offset;
2174
2175         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2176         if (WARN_ON(ret < 0))
2177                 return ret;
2178         ret = 0;
2179
2180         while (1) {
2181                 cond_resched();
2182
2183                 leaf = path->nodes[0];
2184                 slot = path->slots[0];
2185
2186                 if (slot >= btrfs_header_nritems(leaf)) {
2187                         ret = btrfs_next_leaf(root, path);
2188                         if (ret < 0) {
2189                                 goto out;
2190                         } else if (ret > 0) {
2191                                 ret = 0;
2192                                 goto out;
2193                         }
2194                         continue;
2195                 }
2196
2197                 path->slots[0]++;
2198
2199                 btrfs_item_key_to_cpu(leaf, &key, slot);
2200
2201                 if (key.objectid > inum)
2202                         goto out;
2203
2204                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2205                         continue;
2206
2207                 extent = btrfs_item_ptr(leaf, slot,
2208                                         struct btrfs_file_extent_item);
2209
2210                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2211                         continue;
2212
2213                 /*
2214                  * 'offset' refers to the exact key.offset,
2215                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2216                  * (key.offset - extent_offset).
2217                  */
2218                 if (key.offset != offset)
2219                         continue;
2220
2221                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2222                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2223
2224                 if (extent_offset >= old->extent_offset + old->offset +
2225                     old->len || extent_offset + num_bytes <=
2226                     old->extent_offset + old->offset)
2227                         continue;
2228                 break;
2229         }
2230
2231         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2232         if (!backref) {
2233                 ret = -ENOENT;
2234                 goto out;
2235         }
2236
2237         backref->root_id = root_id;
2238         backref->inum = inum;
2239         backref->file_pos = offset;
2240         backref->num_bytes = num_bytes;
2241         backref->extent_offset = extent_offset;
2242         backref->generation = btrfs_file_extent_generation(leaf, extent);
2243         backref->old = old;
2244         backref_insert(&new->root, backref);
2245         old->count++;
2246 out:
2247         btrfs_release_path(path);
2248         WARN_ON(ret);
2249         return ret;
2250 }
2251
2252 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2253                                    struct new_sa_defrag_extent *new)
2254 {
2255         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2256         struct old_sa_defrag_extent *old, *tmp;
2257         int ret;
2258
2259         new->path = path;
2260
2261         list_for_each_entry_safe(old, tmp, &new->head, list) {
2262                 ret = iterate_inodes_from_logical(old->bytenr +
2263                                                   old->extent_offset, fs_info,
2264                                                   path, record_one_backref,
2265                                                   old);
2266                 if (ret < 0 && ret != -ENOENT)
2267                         return false;
2268
2269                 /* no backref to be processed for this extent */
2270                 if (!old->count) {
2271                         list_del(&old->list);
2272                         kfree(old);
2273                 }
2274         }
2275
2276         if (list_empty(&new->head))
2277                 return false;
2278
2279         return true;
2280 }
2281
2282 static int relink_is_mergable(struct extent_buffer *leaf,
2283                               struct btrfs_file_extent_item *fi,
2284                               struct new_sa_defrag_extent *new)
2285 {
2286         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2287                 return 0;
2288
2289         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2290                 return 0;
2291
2292         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2293                 return 0;
2294
2295         if (btrfs_file_extent_encryption(leaf, fi) ||
2296             btrfs_file_extent_other_encoding(leaf, fi))
2297                 return 0;
2298
2299         return 1;
2300 }
2301
2302 /*
2303  * Note the backref might has changed, and in this case we just return 0.
2304  */
2305 static noinline int relink_extent_backref(struct btrfs_path *path,
2306                                  struct sa_defrag_extent_backref *prev,
2307                                  struct sa_defrag_extent_backref *backref)
2308 {
2309         struct btrfs_file_extent_item *extent;
2310         struct btrfs_file_extent_item *item;
2311         struct btrfs_ordered_extent *ordered;
2312         struct btrfs_trans_handle *trans;
2313         struct btrfs_fs_info *fs_info;
2314         struct btrfs_root *root;
2315         struct btrfs_key key;
2316         struct extent_buffer *leaf;
2317         struct old_sa_defrag_extent *old = backref->old;
2318         struct new_sa_defrag_extent *new = old->new;
2319         struct inode *src_inode = new->inode;
2320         struct inode *inode;
2321         struct extent_state *cached = NULL;
2322         int ret = 0;
2323         u64 start;
2324         u64 len;
2325         u64 lock_start;
2326         u64 lock_end;
2327         bool merge = false;
2328         int index;
2329
2330         if (prev && prev->root_id == backref->root_id &&
2331             prev->inum == backref->inum &&
2332             prev->file_pos + prev->num_bytes == backref->file_pos)
2333                 merge = true;
2334
2335         /* step 1: get root */
2336         key.objectid = backref->root_id;
2337         key.type = BTRFS_ROOT_ITEM_KEY;
2338         key.offset = (u64)-1;
2339
2340         fs_info = BTRFS_I(src_inode)->root->fs_info;
2341         index = srcu_read_lock(&fs_info->subvol_srcu);
2342
2343         root = btrfs_read_fs_root_no_name(fs_info, &key);
2344         if (IS_ERR(root)) {
2345                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2346                 if (PTR_ERR(root) == -ENOENT)
2347                         return 0;
2348                 return PTR_ERR(root);
2349         }
2350
2351         if (btrfs_root_readonly(root)) {
2352                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2353                 return 0;
2354         }
2355
2356         /* step 2: get inode */
2357         key.objectid = backref->inum;
2358         key.type = BTRFS_INODE_ITEM_KEY;
2359         key.offset = 0;
2360
2361         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2362         if (IS_ERR(inode)) {
2363                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2364                 return 0;
2365         }
2366
2367         srcu_read_unlock(&fs_info->subvol_srcu, index);
2368
2369         /* step 3: relink backref */
2370         lock_start = backref->file_pos;
2371         lock_end = backref->file_pos + backref->num_bytes - 1;
2372         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2373                          0, &cached);
2374
2375         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2376         if (ordered) {
2377                 btrfs_put_ordered_extent(ordered);
2378                 goto out_unlock;
2379         }
2380
2381         trans = btrfs_join_transaction(root);
2382         if (IS_ERR(trans)) {
2383                 ret = PTR_ERR(trans);
2384                 goto out_unlock;
2385         }
2386
2387         key.objectid = backref->inum;
2388         key.type = BTRFS_EXTENT_DATA_KEY;
2389         key.offset = backref->file_pos;
2390
2391         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2392         if (ret < 0) {
2393                 goto out_free_path;
2394         } else if (ret > 0) {
2395                 ret = 0;
2396                 goto out_free_path;
2397         }
2398
2399         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2400                                 struct btrfs_file_extent_item);
2401
2402         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2403             backref->generation)
2404                 goto out_free_path;
2405
2406         btrfs_release_path(path);
2407
2408         start = backref->file_pos;
2409         if (backref->extent_offset < old->extent_offset + old->offset)
2410                 start += old->extent_offset + old->offset -
2411                          backref->extent_offset;
2412
2413         len = min(backref->extent_offset + backref->num_bytes,
2414                   old->extent_offset + old->offset + old->len);
2415         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2416
2417         ret = btrfs_drop_extents(trans, root, inode, start,
2418                                  start + len, 1);
2419         if (ret)
2420                 goto out_free_path;
2421 again:
2422         key.objectid = btrfs_ino(inode);
2423         key.type = BTRFS_EXTENT_DATA_KEY;
2424         key.offset = start;
2425
2426         path->leave_spinning = 1;
2427         if (merge) {
2428                 struct btrfs_file_extent_item *fi;
2429                 u64 extent_len;
2430                 struct btrfs_key found_key;
2431
2432                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2433                 if (ret < 0)
2434                         goto out_free_path;
2435
2436                 path->slots[0]--;
2437                 leaf = path->nodes[0];
2438                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2439
2440                 fi = btrfs_item_ptr(leaf, path->slots[0],
2441                                     struct btrfs_file_extent_item);
2442                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2443
2444                 if (extent_len + found_key.offset == start &&
2445                     relink_is_mergable(leaf, fi, new)) {
2446                         btrfs_set_file_extent_num_bytes(leaf, fi,
2447                                                         extent_len + len);
2448                         btrfs_mark_buffer_dirty(leaf);
2449                         inode_add_bytes(inode, len);
2450
2451                         ret = 1;
2452                         goto out_free_path;
2453                 } else {
2454                         merge = false;
2455                         btrfs_release_path(path);
2456                         goto again;
2457                 }
2458         }
2459
2460         ret = btrfs_insert_empty_item(trans, root, path, &key,
2461                                         sizeof(*extent));
2462         if (ret) {
2463                 btrfs_abort_transaction(trans, root, ret);
2464                 goto out_free_path;
2465         }
2466
2467         leaf = path->nodes[0];
2468         item = btrfs_item_ptr(leaf, path->slots[0],
2469                                 struct btrfs_file_extent_item);
2470         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2471         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2472         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2473         btrfs_set_file_extent_num_bytes(leaf, item, len);
2474         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2475         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2476         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2477         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2478         btrfs_set_file_extent_encryption(leaf, item, 0);
2479         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2480
2481         btrfs_mark_buffer_dirty(leaf);
2482         inode_add_bytes(inode, len);
2483         btrfs_release_path(path);
2484
2485         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2486                         new->disk_len, 0,
2487                         backref->root_id, backref->inum,
2488                         new->file_pos, 0);      /* start - extent_offset */
2489         if (ret) {
2490                 btrfs_abort_transaction(trans, root, ret);
2491                 goto out_free_path;
2492         }
2493
2494         ret = 1;
2495 out_free_path:
2496         btrfs_release_path(path);
2497         path->leave_spinning = 0;
2498         btrfs_end_transaction(trans, root);
2499 out_unlock:
2500         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2501                              &cached, GFP_NOFS);
2502         iput(inode);
2503         return ret;
2504 }
2505
2506 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2507 {
2508         struct old_sa_defrag_extent *old, *tmp;
2509
2510         if (!new)
2511                 return;
2512
2513         list_for_each_entry_safe(old, tmp, &new->head, list) {
2514                 list_del(&old->list);
2515                 kfree(old);
2516         }
2517         kfree(new);
2518 }
2519
2520 static void relink_file_extents(struct new_sa_defrag_extent *new)
2521 {
2522         struct btrfs_path *path;
2523         struct sa_defrag_extent_backref *backref;
2524         struct sa_defrag_extent_backref *prev = NULL;
2525         struct inode *inode;
2526         struct btrfs_root *root;
2527         struct rb_node *node;
2528         int ret;
2529
2530         inode = new->inode;
2531         root = BTRFS_I(inode)->root;
2532
2533         path = btrfs_alloc_path();
2534         if (!path)
2535                 return;
2536
2537         if (!record_extent_backrefs(path, new)) {
2538                 btrfs_free_path(path);
2539                 goto out;
2540         }
2541         btrfs_release_path(path);
2542
2543         while (1) {
2544                 node = rb_first(&new->root);
2545                 if (!node)
2546                         break;
2547                 rb_erase(node, &new->root);
2548
2549                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2550
2551                 ret = relink_extent_backref(path, prev, backref);
2552                 WARN_ON(ret < 0);
2553
2554                 kfree(prev);
2555
2556                 if (ret == 1)
2557                         prev = backref;
2558                 else
2559                         prev = NULL;
2560                 cond_resched();
2561         }
2562         kfree(prev);
2563
2564         btrfs_free_path(path);
2565 out:
2566         free_sa_defrag_extent(new);
2567
2568         atomic_dec(&root->fs_info->defrag_running);
2569         wake_up(&root->fs_info->transaction_wait);
2570 }
2571
2572 static struct new_sa_defrag_extent *
2573 record_old_file_extents(struct inode *inode,
2574                         struct btrfs_ordered_extent *ordered)
2575 {
2576         struct btrfs_root *root = BTRFS_I(inode)->root;
2577         struct btrfs_path *path;
2578         struct btrfs_key key;
2579         struct old_sa_defrag_extent *old;
2580         struct new_sa_defrag_extent *new;
2581         int ret;
2582
2583         new = kmalloc(sizeof(*new), GFP_NOFS);
2584         if (!new)
2585                 return NULL;
2586
2587         new->inode = inode;
2588         new->file_pos = ordered->file_offset;
2589         new->len = ordered->len;
2590         new->bytenr = ordered->start;
2591         new->disk_len = ordered->disk_len;
2592         new->compress_type = ordered->compress_type;
2593         new->root = RB_ROOT;
2594         INIT_LIST_HEAD(&new->head);
2595
2596         path = btrfs_alloc_path();
2597         if (!path)
2598                 goto out_kfree;
2599
2600         key.objectid = btrfs_ino(inode);
2601         key.type = BTRFS_EXTENT_DATA_KEY;
2602         key.offset = new->file_pos;
2603
2604         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2605         if (ret < 0)
2606                 goto out_free_path;
2607         if (ret > 0 && path->slots[0] > 0)
2608                 path->slots[0]--;
2609
2610         /* find out all the old extents for the file range */
2611         while (1) {
2612                 struct btrfs_file_extent_item *extent;
2613                 struct extent_buffer *l;
2614                 int slot;
2615                 u64 num_bytes;
2616                 u64 offset;
2617                 u64 end;
2618                 u64 disk_bytenr;
2619                 u64 extent_offset;
2620
2621                 l = path->nodes[0];
2622                 slot = path->slots[0];
2623
2624                 if (slot >= btrfs_header_nritems(l)) {
2625                         ret = btrfs_next_leaf(root, path);
2626                         if (ret < 0)
2627                                 goto out_free_path;
2628                         else if (ret > 0)
2629                                 break;
2630                         continue;
2631                 }
2632
2633                 btrfs_item_key_to_cpu(l, &key, slot);
2634
2635                 if (key.objectid != btrfs_ino(inode))
2636                         break;
2637                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2638                         break;
2639                 if (key.offset >= new->file_pos + new->len)
2640                         break;
2641
2642                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2643
2644                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2645                 if (key.offset + num_bytes < new->file_pos)
2646                         goto next;
2647
2648                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2649                 if (!disk_bytenr)
2650                         goto next;
2651
2652                 extent_offset = btrfs_file_extent_offset(l, extent);
2653
2654                 old = kmalloc(sizeof(*old), GFP_NOFS);
2655                 if (!old)
2656                         goto out_free_path;
2657
2658                 offset = max(new->file_pos, key.offset);
2659                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2660
2661                 old->bytenr = disk_bytenr;
2662                 old->extent_offset = extent_offset;
2663                 old->offset = offset - key.offset;
2664                 old->len = end - offset;
2665                 old->new = new;
2666                 old->count = 0;
2667                 list_add_tail(&old->list, &new->head);
2668 next:
2669                 path->slots[0]++;
2670                 cond_resched();
2671         }
2672
2673         btrfs_free_path(path);
2674         atomic_inc(&root->fs_info->defrag_running);
2675
2676         return new;
2677
2678 out_free_path:
2679         btrfs_free_path(path);
2680 out_kfree:
2681         free_sa_defrag_extent(new);
2682         return NULL;
2683 }
2684
2685 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2686                                          u64 start, u64 len)
2687 {
2688         struct btrfs_block_group_cache *cache;
2689
2690         cache = btrfs_lookup_block_group(root->fs_info, start);
2691         ASSERT(cache);
2692
2693         spin_lock(&cache->lock);
2694         cache->delalloc_bytes -= len;
2695         spin_unlock(&cache->lock);
2696
2697         btrfs_put_block_group(cache);
2698 }
2699
2700 /* as ordered data IO finishes, this gets called so we can finish
2701  * an ordered extent if the range of bytes in the file it covers are
2702  * fully written.
2703  */
2704 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2705 {
2706         struct inode *inode = ordered_extent->inode;
2707         struct btrfs_root *root = BTRFS_I(inode)->root;
2708         struct btrfs_trans_handle *trans = NULL;
2709         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2710         struct extent_state *cached_state = NULL;
2711         struct new_sa_defrag_extent *new = NULL;
2712         int compress_type = 0;
2713         int ret = 0;
2714         u64 logical_len = ordered_extent->len;
2715         bool nolock;
2716         bool truncated = false;
2717
2718         nolock = btrfs_is_free_space_inode(inode);
2719
2720         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2721                 ret = -EIO;
2722                 goto out;
2723         }
2724
2725         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2726                                      ordered_extent->file_offset +
2727                                      ordered_extent->len - 1);
2728
2729         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2730                 truncated = true;
2731                 logical_len = ordered_extent->truncated_len;
2732                 /* Truncated the entire extent, don't bother adding */
2733                 if (!logical_len)
2734                         goto out;
2735         }
2736
2737         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2738                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2739                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2740                 if (nolock)
2741                         trans = btrfs_join_transaction_nolock(root);
2742                 else
2743                         trans = btrfs_join_transaction(root);
2744                 if (IS_ERR(trans)) {
2745                         ret = PTR_ERR(trans);
2746                         trans = NULL;
2747                         goto out;
2748                 }
2749                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2750                 ret = btrfs_update_inode_fallback(trans, root, inode);
2751                 if (ret) /* -ENOMEM or corruption */
2752                         btrfs_abort_transaction(trans, root, ret);
2753                 goto out;
2754         }
2755
2756         lock_extent_bits(io_tree, ordered_extent->file_offset,
2757                          ordered_extent->file_offset + ordered_extent->len - 1,
2758                          0, &cached_state);
2759
2760         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2761                         ordered_extent->file_offset + ordered_extent->len - 1,
2762                         EXTENT_DEFRAG, 1, cached_state);
2763         if (ret) {
2764                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2765                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2766                         /* the inode is shared */
2767                         new = record_old_file_extents(inode, ordered_extent);
2768
2769                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2770                         ordered_extent->file_offset + ordered_extent->len - 1,
2771                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2772         }
2773
2774         if (nolock)
2775                 trans = btrfs_join_transaction_nolock(root);
2776         else
2777                 trans = btrfs_join_transaction(root);
2778         if (IS_ERR(trans)) {
2779                 ret = PTR_ERR(trans);
2780                 trans = NULL;
2781                 goto out_unlock;
2782         }
2783
2784         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2785
2786         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2787                 compress_type = ordered_extent->compress_type;
2788         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2789                 BUG_ON(compress_type);
2790                 ret = btrfs_mark_extent_written(trans, inode,
2791                                                 ordered_extent->file_offset,
2792                                                 ordered_extent->file_offset +
2793                                                 logical_len);
2794         } else {
2795                 BUG_ON(root == root->fs_info->tree_root);
2796                 ret = insert_reserved_file_extent(trans, inode,
2797                                                 ordered_extent->file_offset,
2798                                                 ordered_extent->start,
2799                                                 ordered_extent->disk_len,
2800                                                 logical_len, logical_len,
2801                                                 compress_type, 0, 0,
2802                                                 BTRFS_FILE_EXTENT_REG);
2803                 if (!ret)
2804                         btrfs_release_delalloc_bytes(root,
2805                                                      ordered_extent->start,
2806                                                      ordered_extent->disk_len);
2807         }
2808         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2809                            ordered_extent->file_offset, ordered_extent->len,
2810                            trans->transid);
2811         if (ret < 0) {
2812                 btrfs_abort_transaction(trans, root, ret);
2813                 goto out_unlock;
2814         }
2815
2816         add_pending_csums(trans, inode, ordered_extent->file_offset,
2817                           &ordered_extent->list);
2818
2819         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2820         ret = btrfs_update_inode_fallback(trans, root, inode);
2821         if (ret) { /* -ENOMEM or corruption */
2822                 btrfs_abort_transaction(trans, root, ret);
2823                 goto out_unlock;
2824         }
2825         ret = 0;
2826 out_unlock:
2827         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2828                              ordered_extent->file_offset +
2829                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2830 out:
2831         if (root != root->fs_info->tree_root)
2832                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2833         if (trans)
2834                 btrfs_end_transaction(trans, root);
2835
2836         if (ret || truncated) {
2837                 u64 start, end;
2838
2839                 if (truncated)
2840                         start = ordered_extent->file_offset + logical_len;
2841                 else
2842                         start = ordered_extent->file_offset;
2843                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2844                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2845
2846                 /* Drop the cache for the part of the extent we didn't write. */
2847                 btrfs_drop_extent_cache(inode, start, end, 0);
2848
2849                 /*
2850                  * If the ordered extent had an IOERR or something else went
2851                  * wrong we need to return the space for this ordered extent
2852                  * back to the allocator.  We only free the extent in the
2853                  * truncated case if we didn't write out the extent at all.
2854                  */
2855                 if ((ret || !logical_len) &&
2856                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2857                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2858                         btrfs_free_reserved_extent(root, ordered_extent->start,
2859                                                    ordered_extent->disk_len, 1);
2860         }
2861
2862
2863         /*
2864          * This needs to be done to make sure anybody waiting knows we are done
2865          * updating everything for this ordered extent.
2866          */
2867         btrfs_remove_ordered_extent(inode, ordered_extent);
2868
2869         /* for snapshot-aware defrag */
2870         if (new) {
2871                 if (ret) {
2872                         free_sa_defrag_extent(new);
2873                         atomic_dec(&root->fs_info->defrag_running);
2874                 } else {
2875                         relink_file_extents(new);
2876                 }
2877         }
2878
2879         /* once for us */
2880         btrfs_put_ordered_extent(ordered_extent);
2881         /* once for the tree */
2882         btrfs_put_ordered_extent(ordered_extent);
2883
2884         return ret;
2885 }
2886
2887 static void finish_ordered_fn(struct btrfs_work *work)
2888 {
2889         struct btrfs_ordered_extent *ordered_extent;
2890         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2891         btrfs_finish_ordered_io(ordered_extent);
2892 }
2893
2894 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2895                                 struct extent_state *state, int uptodate)
2896 {
2897         struct inode *inode = page->mapping->host;
2898         struct btrfs_root *root = BTRFS_I(inode)->root;
2899         struct btrfs_ordered_extent *ordered_extent = NULL;
2900         struct btrfs_workqueue *wq;
2901         btrfs_work_func_t func;
2902
2903         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2904
2905         ClearPagePrivate2(page);
2906         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2907                                             end - start + 1, uptodate))
2908                 return 0;
2909
2910         if (btrfs_is_free_space_inode(inode)) {
2911                 wq = root->fs_info->endio_freespace_worker;
2912                 func = btrfs_freespace_write_helper;
2913         } else {
2914                 wq = root->fs_info->endio_write_workers;
2915                 func = btrfs_endio_write_helper;
2916         }
2917
2918         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
2919                         NULL);
2920         btrfs_queue_work(wq, &ordered_extent->work);
2921
2922         return 0;
2923 }
2924
2925 static int __readpage_endio_check(struct inode *inode,
2926                                   struct btrfs_io_bio *io_bio,
2927                                   int icsum, struct page *page,
2928                                   int pgoff, u64 start, size_t len)
2929 {
2930         char *kaddr;
2931         u32 csum_expected;
2932         u32 csum = ~(u32)0;
2933         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2934                                       DEFAULT_RATELIMIT_BURST);
2935
2936         csum_expected = *(((u32 *)io_bio->csum) + icsum);
2937
2938         kaddr = kmap_atomic(page);
2939         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
2940         btrfs_csum_final(csum, (char *)&csum);
2941         if (csum != csum_expected)
2942                 goto zeroit;
2943
2944         kunmap_atomic(kaddr);
2945         return 0;
2946 zeroit:
2947         if (__ratelimit(&_rs))
2948                 btrfs_info(BTRFS_I(inode)->root->fs_info,
2949                            "csum failed ino %llu off %llu csum %u expected csum %u",
2950                            btrfs_ino(inode), start, csum, csum_expected);
2951         memset(kaddr + pgoff, 1, len);
2952         flush_dcache_page(page);
2953         kunmap_atomic(kaddr);
2954         if (csum_expected == 0)
2955                 return 0;
2956         return -EIO;
2957 }
2958
2959 /*
2960  * when reads are done, we need to check csums to verify the data is correct
2961  * if there's a match, we allow the bio to finish.  If not, the code in
2962  * extent_io.c will try to find good copies for us.
2963  */
2964 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2965                                       u64 phy_offset, struct page *page,
2966                                       u64 start, u64 end, int mirror)
2967 {
2968         size_t offset = start - page_offset(page);
2969         struct inode *inode = page->mapping->host;
2970         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2971         struct btrfs_root *root = BTRFS_I(inode)->root;
2972
2973         if (PageChecked(page)) {
2974                 ClearPageChecked(page);
2975                 return 0;
2976         }
2977
2978         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2979                 return 0;
2980
2981         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2982             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2983                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2984                                   GFP_NOFS);
2985                 return 0;
2986         }
2987
2988         phy_offset >>= inode->i_sb->s_blocksize_bits;
2989         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
2990                                       start, (size_t)(end - start + 1));
2991 }
2992
2993 struct delayed_iput {
2994         struct list_head list;
2995         struct inode *inode;
2996 };
2997
2998 /* JDM: If this is fs-wide, why can't we add a pointer to
2999  * btrfs_inode instead and avoid the allocation? */
3000 void btrfs_add_delayed_iput(struct inode *inode)
3001 {
3002         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3003         struct delayed_iput *delayed;
3004
3005         if (atomic_add_unless(&inode->i_count, -1, 1))
3006                 return;
3007
3008         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
3009         delayed->inode = inode;
3010
3011         spin_lock(&fs_info->delayed_iput_lock);
3012         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
3013         spin_unlock(&fs_info->delayed_iput_lock);
3014 }
3015
3016 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3017 {
3018         LIST_HEAD(list);
3019         struct btrfs_fs_info *fs_info = root->fs_info;
3020         struct delayed_iput *delayed;
3021         int empty;
3022
3023         spin_lock(&fs_info->delayed_iput_lock);
3024         empty = list_empty(&fs_info->delayed_iputs);
3025         spin_unlock(&fs_info->delayed_iput_lock);
3026         if (empty)
3027                 return;
3028
3029         spin_lock(&fs_info->delayed_iput_lock);
3030         list_splice_init(&fs_info->delayed_iputs, &list);
3031         spin_unlock(&fs_info->delayed_iput_lock);
3032
3033         while (!list_empty(&list)) {
3034                 delayed = list_entry(list.next, struct delayed_iput, list);
3035                 list_del(&delayed->list);
3036                 iput(delayed->inode);
3037                 kfree(delayed);
3038         }
3039 }
3040
3041 /*
3042  * This is called in transaction commit time. If there are no orphan
3043  * files in the subvolume, it removes orphan item and frees block_rsv
3044  * structure.
3045  */
3046 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3047                               struct btrfs_root *root)
3048 {
3049         struct btrfs_block_rsv *block_rsv;
3050         int ret;
3051
3052         if (atomic_read(&root->orphan_inodes) ||
3053             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3054                 return;
3055
3056         spin_lock(&root->orphan_lock);
3057         if (atomic_read(&root->orphan_inodes)) {
3058                 spin_unlock(&root->orphan_lock);
3059                 return;
3060         }
3061
3062         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3063                 spin_unlock(&root->orphan_lock);
3064                 return;
3065         }
3066
3067         block_rsv = root->orphan_block_rsv;
3068         root->orphan_block_rsv = NULL;
3069         spin_unlock(&root->orphan_lock);
3070
3071         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3072             btrfs_root_refs(&root->root_item) > 0) {
3073                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3074                                             root->root_key.objectid);
3075                 if (ret)
3076                         btrfs_abort_transaction(trans, root, ret);
3077                 else
3078                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3079                                   &root->state);
3080         }
3081
3082         if (block_rsv) {
3083                 WARN_ON(block_rsv->size > 0);
3084                 btrfs_free_block_rsv(root, block_rsv);
3085         }
3086 }
3087
3088 /*
3089  * This creates an orphan entry for the given inode in case something goes
3090  * wrong in the middle of an unlink/truncate.
3091  *
3092  * NOTE: caller of this function should reserve 5 units of metadata for
3093  *       this function.
3094  */
3095 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3096 {
3097         struct btrfs_root *root = BTRFS_I(inode)->root;
3098         struct btrfs_block_rsv *block_rsv = NULL;
3099         int reserve = 0;
3100         int insert = 0;
3101         int ret;
3102
3103         if (!root->orphan_block_rsv) {
3104                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3105                 if (!block_rsv)
3106                         return -ENOMEM;
3107         }
3108
3109         spin_lock(&root->orphan_lock);
3110         if (!root->orphan_block_rsv) {
3111                 root->orphan_block_rsv = block_rsv;
3112         } else if (block_rsv) {
3113                 btrfs_free_block_rsv(root, block_rsv);
3114                 block_rsv = NULL;
3115         }
3116
3117         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3118                               &BTRFS_I(inode)->runtime_flags)) {
3119 #if 0
3120                 /*
3121                  * For proper ENOSPC handling, we should do orphan
3122                  * cleanup when mounting. But this introduces backward
3123                  * compatibility issue.
3124                  */
3125                 if (!xchg(&root->orphan_item_inserted, 1))
3126                         insert = 2;
3127                 else
3128                         insert = 1;
3129 #endif
3130                 insert = 1;
3131                 atomic_inc(&root->orphan_inodes);
3132         }
3133
3134         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3135                               &BTRFS_I(inode)->runtime_flags))
3136                 reserve = 1;
3137         spin_unlock(&root->orphan_lock);
3138
3139         /* grab metadata reservation from transaction handle */
3140         if (reserve) {
3141                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3142                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3143         }
3144
3145         /* insert an orphan item to track this unlinked/truncated file */
3146         if (insert >= 1) {
3147                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3148                 if (ret) {
3149                         atomic_dec(&root->orphan_inodes);
3150                         if (reserve) {
3151                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3152                                           &BTRFS_I(inode)->runtime_flags);
3153                                 btrfs_orphan_release_metadata(inode);
3154                         }
3155                         if (ret != -EEXIST) {
3156                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3157                                           &BTRFS_I(inode)->runtime_flags);
3158                                 btrfs_abort_transaction(trans, root, ret);
3159                                 return ret;
3160                         }
3161                 }
3162                 ret = 0;
3163         }
3164
3165         /* insert an orphan item to track subvolume contains orphan files */
3166         if (insert >= 2) {
3167                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3168                                                root->root_key.objectid);
3169                 if (ret && ret != -EEXIST) {
3170                         btrfs_abort_transaction(trans, root, ret);
3171                         return ret;
3172                 }
3173         }
3174         return 0;
3175 }
3176
3177 /*
3178  * We have done the truncate/delete so we can go ahead and remove the orphan
3179  * item for this particular inode.
3180  */
3181 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3182                             struct inode *inode)
3183 {
3184         struct btrfs_root *root = BTRFS_I(inode)->root;
3185         int delete_item = 0;
3186         int release_rsv = 0;
3187         int ret = 0;
3188
3189         spin_lock(&root->orphan_lock);
3190         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3191                                &BTRFS_I(inode)->runtime_flags))
3192                 delete_item = 1;
3193
3194         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3195                                &BTRFS_I(inode)->runtime_flags))
3196                 release_rsv = 1;
3197         spin_unlock(&root->orphan_lock);
3198
3199         if (delete_item) {
3200                 atomic_dec(&root->orphan_inodes);
3201                 if (trans)
3202                         ret = btrfs_del_orphan_item(trans, root,
3203                                                     btrfs_ino(inode));
3204         }
3205
3206         if (release_rsv)
3207                 btrfs_orphan_release_metadata(inode);
3208
3209         return ret;
3210 }
3211
3212 /*
3213  * this cleans up any orphans that may be left on the list from the last use
3214  * of this root.
3215  */
3216 int btrfs_orphan_cleanup(struct btrfs_root *root)
3217 {
3218         struct btrfs_path *path;
3219         struct extent_buffer *leaf;
3220         struct btrfs_key key, found_key;
3221         struct btrfs_trans_handle *trans;
3222         struct inode *inode;
3223         u64 last_objectid = 0;
3224         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3225
3226         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3227                 return 0;
3228
3229         path = btrfs_alloc_path();
3230         if (!path) {
3231                 ret = -ENOMEM;
3232                 goto out;
3233         }
3234         path->reada = -1;
3235
3236         key.objectid = BTRFS_ORPHAN_OBJECTID;
3237         key.type = BTRFS_ORPHAN_ITEM_KEY;
3238         key.offset = (u64)-1;
3239
3240         while (1) {
3241                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3242                 if (ret < 0)
3243                         goto out;
3244
3245                 /*
3246                  * if ret == 0 means we found what we were searching for, which
3247                  * is weird, but possible, so only screw with path if we didn't
3248                  * find the key and see if we have stuff that matches
3249                  */
3250                 if (ret > 0) {
3251                         ret = 0;
3252                         if (path->slots[0] == 0)
3253                                 break;
3254                         path->slots[0]--;
3255                 }
3256
3257                 /* pull out the item */
3258                 leaf = path->nodes[0];
3259                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3260
3261                 /* make sure the item matches what we want */
3262                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3263                         break;
3264                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3265                         break;
3266
3267                 /* release the path since we're done with it */
3268                 btrfs_release_path(path);
3269
3270                 /*
3271                  * this is where we are basically btrfs_lookup, without the
3272                  * crossing root thing.  we store the inode number in the
3273                  * offset of the orphan item.
3274                  */
3275
3276                 if (found_key.offset == last_objectid) {
3277                         btrfs_err(root->fs_info,
3278                                 "Error removing orphan entry, stopping orphan cleanup");
3279                         ret = -EINVAL;
3280                         goto out;
3281                 }
3282
3283                 last_objectid = found_key.offset;
3284
3285                 found_key.objectid = found_key.offset;
3286                 found_key.type = BTRFS_INODE_ITEM_KEY;
3287                 found_key.offset = 0;
3288                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3289                 ret = PTR_ERR_OR_ZERO(inode);
3290                 if (ret && ret != -ESTALE)
3291                         goto out;
3292
3293                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3294                         struct btrfs_root *dead_root;
3295                         struct btrfs_fs_info *fs_info = root->fs_info;
3296                         int is_dead_root = 0;
3297
3298                         /*
3299                          * this is an orphan in the tree root. Currently these
3300                          * could come from 2 sources:
3301                          *  a) a snapshot deletion in progress
3302                          *  b) a free space cache inode
3303                          * We need to distinguish those two, as the snapshot
3304                          * orphan must not get deleted.
3305                          * find_dead_roots already ran before us, so if this
3306                          * is a snapshot deletion, we should find the root
3307                          * in the dead_roots list
3308                          */
3309                         spin_lock(&fs_info->trans_lock);
3310                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3311                                             root_list) {
3312                                 if (dead_root->root_key.objectid ==
3313                                     found_key.objectid) {
3314                                         is_dead_root = 1;
3315                                         break;
3316                                 }
3317                         }
3318                         spin_unlock(&fs_info->trans_lock);
3319                         if (is_dead_root) {
3320                                 /* prevent this orphan from being found again */
3321                                 key.offset = found_key.objectid - 1;
3322                                 continue;
3323                         }
3324                 }
3325                 /*
3326                  * Inode is already gone but the orphan item is still there,
3327                  * kill the orphan item.
3328                  */
3329                 if (ret == -ESTALE) {
3330                         trans = btrfs_start_transaction(root, 1);
3331                         if (IS_ERR(trans)) {
3332                                 ret = PTR_ERR(trans);
3333                                 goto out;
3334                         }
3335                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3336                                 found_key.objectid);
3337                         ret = btrfs_del_orphan_item(trans, root,
3338                                                     found_key.objectid);
3339                         btrfs_end_transaction(trans, root);
3340                         if (ret)
3341                                 goto out;
3342                         continue;
3343                 }
3344
3345                 /*
3346                  * add this inode to the orphan list so btrfs_orphan_del does
3347                  * the proper thing when we hit it
3348                  */
3349                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3350                         &BTRFS_I(inode)->runtime_flags);
3351                 atomic_inc(&root->orphan_inodes);
3352
3353                 /* if we have links, this was a truncate, lets do that */
3354                 if (inode->i_nlink) {
3355                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3356                                 iput(inode);
3357                                 continue;
3358                         }
3359                         nr_truncate++;
3360
3361                         /* 1 for the orphan item deletion. */
3362                         trans = btrfs_start_transaction(root, 1);
3363                         if (IS_ERR(trans)) {
3364                                 iput(inode);
3365                                 ret = PTR_ERR(trans);
3366                                 goto out;
3367                         }
3368                         ret = btrfs_orphan_add(trans, inode);
3369                         btrfs_end_transaction(trans, root);
3370                         if (ret) {
3371                                 iput(inode);
3372                                 goto out;
3373                         }
3374
3375                         ret = btrfs_truncate(inode);
3376                         if (ret)
3377                                 btrfs_orphan_del(NULL, inode);
3378                 } else {
3379                         nr_unlink++;
3380                 }
3381
3382                 /* this will do delete_inode and everything for us */
3383                 iput(inode);
3384                 if (ret)
3385                         goto out;
3386         }
3387         /* release the path since we're done with it */
3388         btrfs_release_path(path);
3389
3390         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3391
3392         if (root->orphan_block_rsv)
3393                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3394                                         (u64)-1);
3395
3396         if (root->orphan_block_rsv ||
3397             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3398                 trans = btrfs_join_transaction(root);
3399                 if (!IS_ERR(trans))
3400                         btrfs_end_transaction(trans, root);
3401         }
3402
3403         if (nr_unlink)
3404                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3405         if (nr_truncate)
3406                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3407
3408 out:
3409         if (ret)
3410                 btrfs_crit(root->fs_info,
3411                         "could not do orphan cleanup %d", ret);
3412         btrfs_free_path(path);
3413         return ret;
3414 }
3415
3416 /*
3417  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3418  * don't find any xattrs, we know there can't be any acls.
3419  *
3420  * slot is the slot the inode is in, objectid is the objectid of the inode
3421  */
3422 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3423                                           int slot, u64 objectid,
3424                                           int *first_xattr_slot)
3425 {
3426         u32 nritems = btrfs_header_nritems(leaf);
3427         struct btrfs_key found_key;
3428         static u64 xattr_access = 0;
3429         static u64 xattr_default = 0;
3430         int scanned = 0;
3431
3432         if (!xattr_access) {
3433                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3434                                         strlen(POSIX_ACL_XATTR_ACCESS));
3435                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3436                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3437         }
3438
3439         slot++;
3440         *first_xattr_slot = -1;
3441         while (slot < nritems) {
3442                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3443
3444                 /* we found a different objectid, there must not be acls */
3445                 if (found_key.objectid != objectid)
3446                         return 0;
3447
3448                 /* we found an xattr, assume we've got an acl */
3449                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3450                         if (*first_xattr_slot == -1)
3451                                 *first_xattr_slot = slot;
3452                         if (found_key.offset == xattr_access ||
3453                             found_key.offset == xattr_default)
3454                                 return 1;
3455                 }
3456
3457                 /*
3458                  * we found a key greater than an xattr key, there can't
3459                  * be any acls later on
3460                  */
3461                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3462                         return 0;
3463
3464                 slot++;
3465                 scanned++;
3466
3467                 /*
3468                  * it goes inode, inode backrefs, xattrs, extents,
3469                  * so if there are a ton of hard links to an inode there can
3470                  * be a lot of backrefs.  Don't waste time searching too hard,
3471                  * this is just an optimization
3472                  */
3473                 if (scanned >= 8)
3474                         break;
3475         }
3476         /* we hit the end of the leaf before we found an xattr or
3477          * something larger than an xattr.  We have to assume the inode
3478          * has acls
3479          */
3480         if (*first_xattr_slot == -1)
3481                 *first_xattr_slot = slot;
3482         return 1;
3483 }
3484
3485 /*
3486  * read an inode from the btree into the in-memory inode
3487  */
3488 static void btrfs_read_locked_inode(struct inode *inode)
3489 {
3490         struct btrfs_path *path;
3491         struct extent_buffer *leaf;
3492         struct btrfs_inode_item *inode_item;
3493         struct btrfs_timespec *tspec;
3494         struct btrfs_root *root = BTRFS_I(inode)->root;
3495         struct btrfs_key location;
3496         unsigned long ptr;
3497         int maybe_acls;
3498         u32 rdev;
3499         int ret;
3500         bool filled = false;
3501         int first_xattr_slot;
3502
3503         ret = btrfs_fill_inode(inode, &rdev);
3504         if (!ret)
3505                 filled = true;
3506
3507         path = btrfs_alloc_path();
3508         if (!path)
3509                 goto make_bad;
3510
3511         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3512
3513         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3514         if (ret)
3515                 goto make_bad;
3516
3517         leaf = path->nodes[0];
3518
3519         if (filled)
3520                 goto cache_index;
3521
3522         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3523                                     struct btrfs_inode_item);
3524         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3525         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3526         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3527         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3528         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3529
3530         tspec = btrfs_inode_atime(inode_item);
3531         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3532         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3533
3534         tspec = btrfs_inode_mtime(inode_item);
3535         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3536         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3537
3538         tspec = btrfs_inode_ctime(inode_item);
3539         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3540         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3541
3542         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3543         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3544         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3545
3546         /*
3547          * If we were modified in the current generation and evicted from memory
3548          * and then re-read we need to do a full sync since we don't have any
3549          * idea about which extents were modified before we were evicted from
3550          * cache.
3551          */
3552         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3553                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3554                         &BTRFS_I(inode)->runtime_flags);
3555
3556         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3557         inode->i_generation = BTRFS_I(inode)->generation;
3558         inode->i_rdev = 0;
3559         rdev = btrfs_inode_rdev(leaf, inode_item);
3560
3561         BTRFS_I(inode)->index_cnt = (u64)-1;
3562         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3563
3564 cache_index:
3565         path->slots[0]++;
3566         if (inode->i_nlink != 1 ||
3567             path->slots[0] >= btrfs_header_nritems(leaf))
3568                 goto cache_acl;
3569
3570         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3571         if (location.objectid != btrfs_ino(inode))
3572                 goto cache_acl;
3573
3574         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3575         if (location.type == BTRFS_INODE_REF_KEY) {
3576                 struct btrfs_inode_ref *ref;
3577
3578                 ref = (struct btrfs_inode_ref *)ptr;
3579                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3580         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3581                 struct btrfs_inode_extref *extref;
3582
3583                 extref = (struct btrfs_inode_extref *)ptr;
3584                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3585                                                                      extref);
3586         }
3587 cache_acl:
3588         /*
3589          * try to precache a NULL acl entry for files that don't have
3590          * any xattrs or acls
3591          */
3592         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3593                                            btrfs_ino(inode), &first_xattr_slot);
3594         if (first_xattr_slot != -1) {
3595                 path->slots[0] = first_xattr_slot;
3596                 ret = btrfs_load_inode_props(inode, path);
3597                 if (ret)
3598                         btrfs_err(root->fs_info,
3599                                   "error loading props for ino %llu (root %llu): %d",
3600                                   btrfs_ino(inode),
3601                                   root->root_key.objectid, ret);
3602         }
3603         btrfs_free_path(path);
3604
3605         if (!maybe_acls)
3606                 cache_no_acl(inode);
3607
3608         switch (inode->i_mode & S_IFMT) {
3609         case S_IFREG:
3610                 inode->i_mapping->a_ops = &btrfs_aops;
3611                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3612                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3613                 inode->i_fop = &btrfs_file_operations;
3614                 inode->i_op = &btrfs_file_inode_operations;
3615                 break;
3616         case S_IFDIR:
3617                 inode->i_fop = &btrfs_dir_file_operations;
3618                 if (root == root->fs_info->tree_root)
3619                         inode->i_op = &btrfs_dir_ro_inode_operations;
3620                 else
3621                         inode->i_op = &btrfs_dir_inode_operations;
3622                 break;
3623         case S_IFLNK:
3624                 inode->i_op = &btrfs_symlink_inode_operations;
3625                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3626                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3627                 break;
3628         default:
3629                 inode->i_op = &btrfs_special_inode_operations;
3630                 init_special_inode(inode, inode->i_mode, rdev);
3631                 break;
3632         }
3633
3634         btrfs_update_iflags(inode);
3635         return;
3636
3637 make_bad:
3638         btrfs_free_path(path);
3639         make_bad_inode(inode);
3640 }
3641
3642 /*
3643  * given a leaf and an inode, copy the inode fields into the leaf
3644  */
3645 static void fill_inode_item(struct btrfs_trans_handle *trans,
3646                             struct extent_buffer *leaf,
3647                             struct btrfs_inode_item *item,
3648                             struct inode *inode)
3649 {
3650         struct btrfs_map_token token;
3651
3652         btrfs_init_map_token(&token);
3653
3654         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3655         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3656         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3657                                    &token);
3658         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3659         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3660
3661         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3662                                      inode->i_atime.tv_sec, &token);
3663         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3664                                       inode->i_atime.tv_nsec, &token);
3665
3666         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3667                                      inode->i_mtime.tv_sec, &token);
3668         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3669                                       inode->i_mtime.tv_nsec, &token);
3670
3671         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3672                                      inode->i_ctime.tv_sec, &token);
3673         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3674                                       inode->i_ctime.tv_nsec, &token);
3675
3676         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3677                                      &token);
3678         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3679                                          &token);
3680         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3681         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3682         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3683         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3684         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3685 }
3686
3687 /*
3688  * copy everything in the in-memory inode into the btree.
3689  */
3690 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3691                                 struct btrfs_root *root, struct inode *inode)
3692 {
3693         struct btrfs_inode_item *inode_item;
3694         struct btrfs_path *path;
3695         struct extent_buffer *leaf;
3696         int ret;
3697
3698         path = btrfs_alloc_path();
3699         if (!path)
3700                 return -ENOMEM;
3701
3702         path->leave_spinning = 1;
3703         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3704                                  1);
3705         if (ret) {
3706                 if (ret > 0)
3707                         ret = -ENOENT;
3708                 goto failed;
3709         }
3710
3711         leaf = path->nodes[0];
3712         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3713                                     struct btrfs_inode_item);
3714
3715         fill_inode_item(trans, leaf, inode_item, inode);
3716         btrfs_mark_buffer_dirty(leaf);
3717         btrfs_set_inode_last_trans(trans, inode);
3718         ret = 0;
3719 failed:
3720         btrfs_free_path(path);
3721         return ret;
3722 }
3723
3724 /*
3725  * copy everything in the in-memory inode into the btree.
3726  */
3727 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3728                                 struct btrfs_root *root, struct inode *inode)
3729 {
3730         int ret;
3731
3732         /*
3733          * If the inode is a free space inode, we can deadlock during commit
3734          * if we put it into the delayed code.
3735          *
3736          * The data relocation inode should also be directly updated
3737          * without delay
3738          */
3739         if (!btrfs_is_free_space_inode(inode)
3740             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3741             && !root->fs_info->log_root_recovering) {
3742                 btrfs_update_root_times(trans, root);
3743
3744                 ret = btrfs_delayed_update_inode(trans, root, inode);
3745                 if (!ret)
3746                         btrfs_set_inode_last_trans(trans, inode);
3747                 return ret;
3748         }
3749
3750         return btrfs_update_inode_item(trans, root, inode);
3751 }
3752
3753 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3754                                          struct btrfs_root *root,
3755                                          struct inode *inode)
3756 {
3757         int ret;
3758
3759         ret = btrfs_update_inode(trans, root, inode);
3760         if (ret == -ENOSPC)
3761                 return btrfs_update_inode_item(trans, root, inode);
3762         return ret;
3763 }
3764
3765 /*
3766  * unlink helper that gets used here in inode.c and in the tree logging
3767  * recovery code.  It remove a link in a directory with a given name, and
3768  * also drops the back refs in the inode to the directory
3769  */
3770 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3771                                 struct btrfs_root *root,
3772                                 struct inode *dir, struct inode *inode,
3773                                 const char *name, int name_len)
3774 {
3775         struct btrfs_path *path;
3776         int ret = 0;
3777         struct extent_buffer *leaf;
3778         struct btrfs_dir_item *di;
3779         struct btrfs_key key;
3780         u64 index;
3781         u64 ino = btrfs_ino(inode);
3782         u64 dir_ino = btrfs_ino(dir);
3783
3784         path = btrfs_alloc_path();
3785         if (!path) {
3786                 ret = -ENOMEM;
3787                 goto out;
3788         }
3789
3790         path->leave_spinning = 1;
3791         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3792                                     name, name_len, -1);
3793         if (IS_ERR(di)) {
3794                 ret = PTR_ERR(di);
3795                 goto err;
3796         }
3797         if (!di) {
3798                 ret = -ENOENT;
3799                 goto err;
3800         }
3801         leaf = path->nodes[0];
3802         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3803         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3804         if (ret)
3805                 goto err;
3806         btrfs_release_path(path);
3807
3808         /*
3809          * If we don't have dir index, we have to get it by looking up
3810          * the inode ref, since we get the inode ref, remove it directly,
3811          * it is unnecessary to do delayed deletion.
3812          *
3813          * But if we have dir index, needn't search inode ref to get it.
3814          * Since the inode ref is close to the inode item, it is better
3815          * that we delay to delete it, and just do this deletion when
3816          * we update the inode item.
3817          */
3818         if (BTRFS_I(inode)->dir_index) {
3819                 ret = btrfs_delayed_delete_inode_ref(inode);
3820                 if (!ret) {
3821                         index = BTRFS_I(inode)->dir_index;
3822                         goto skip_backref;
3823                 }
3824         }
3825
3826         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3827                                   dir_ino, &index);
3828         if (ret) {
3829                 btrfs_info(root->fs_info,
3830                         "failed to delete reference to %.*s, inode %llu parent %llu",
3831                         name_len, name, ino, dir_ino);
3832                 btrfs_abort_transaction(trans, root, ret);
3833                 goto err;
3834         }
3835 skip_backref:
3836         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3837         if (ret) {
3838                 btrfs_abort_transaction(trans, root, ret);
3839                 goto err;
3840         }
3841
3842         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3843                                          inode, dir_ino);
3844         if (ret != 0 && ret != -ENOENT) {
3845                 btrfs_abort_transaction(trans, root, ret);
3846                 goto err;
3847         }
3848
3849         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3850                                            dir, index);
3851         if (ret == -ENOENT)
3852                 ret = 0;
3853         else if (ret)
3854                 btrfs_abort_transaction(trans, root, ret);
3855 err:
3856         btrfs_free_path(path);
3857         if (ret)
3858                 goto out;
3859
3860         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3861         inode_inc_iversion(inode);
3862         inode_inc_iversion(dir);
3863         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3864         ret = btrfs_update_inode(trans, root, dir);
3865 out:
3866         return ret;
3867 }
3868
3869 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3870                        struct btrfs_root *root,
3871                        struct inode *dir, struct inode *inode,
3872                        const char *name, int name_len)
3873 {
3874         int ret;
3875         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3876         if (!ret) {
3877                 drop_nlink(inode);
3878                 ret = btrfs_update_inode(trans, root, inode);
3879         }
3880         return ret;
3881 }
3882
3883 /*
3884  * helper to start transaction for unlink and rmdir.
3885  *
3886  * unlink and rmdir are special in btrfs, they do not always free space, so
3887  * if we cannot make our reservations the normal way try and see if there is
3888  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3889  * allow the unlink to occur.
3890  */
3891 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3892 {
3893         struct btrfs_trans_handle *trans;
3894         struct btrfs_root *root = BTRFS_I(dir)->root;
3895         int ret;
3896
3897         /*
3898          * 1 for the possible orphan item
3899          * 1 for the dir item
3900          * 1 for the dir index
3901          * 1 for the inode ref
3902          * 1 for the inode
3903          */
3904         trans = btrfs_start_transaction(root, 5);
3905         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3906                 return trans;
3907
3908         if (PTR_ERR(trans) == -ENOSPC) {
3909                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3910
3911                 trans = btrfs_start_transaction(root, 0);
3912                 if (IS_ERR(trans))
3913                         return trans;
3914                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3915                                                &root->fs_info->trans_block_rsv,
3916                                                num_bytes, 5);
3917                 if (ret) {
3918                         btrfs_end_transaction(trans, root);
3919                         return ERR_PTR(ret);
3920                 }
3921                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3922                 trans->bytes_reserved = num_bytes;
3923         }
3924         return trans;
3925 }
3926
3927 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3928 {
3929         struct btrfs_root *root = BTRFS_I(dir)->root;
3930         struct btrfs_trans_handle *trans;
3931         struct inode *inode = dentry->d_inode;
3932         int ret;
3933
3934         trans = __unlink_start_trans(dir);
3935         if (IS_ERR(trans))
3936                 return PTR_ERR(trans);
3937
3938         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3939
3940         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3941                                  dentry->d_name.name, dentry->d_name.len);
3942         if (ret)
3943                 goto out;
3944
3945         if (inode->i_nlink == 0) {
3946                 ret = btrfs_orphan_add(trans, inode);
3947                 if (ret)
3948                         goto out;
3949         }
3950
3951 out:
3952         btrfs_end_transaction(trans, root);
3953         btrfs_btree_balance_dirty(root);
3954         return ret;
3955 }
3956
3957 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3958                         struct btrfs_root *root,
3959                         struct inode *dir, u64 objectid,
3960                         const char *name, int name_len)
3961 {
3962         struct btrfs_path *path;
3963         struct extent_buffer *leaf;
3964         struct btrfs_dir_item *di;
3965         struct btrfs_key key;
3966         u64 index;
3967         int ret;
3968         u64 dir_ino = btrfs_ino(dir);
3969
3970         path = btrfs_alloc_path();
3971         if (!path)
3972                 return -ENOMEM;
3973
3974         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3975                                    name, name_len, -1);
3976         if (IS_ERR_OR_NULL(di)) {
3977                 if (!di)
3978                         ret = -ENOENT;
3979                 else
3980                         ret = PTR_ERR(di);
3981                 goto out;
3982         }
3983
3984         leaf = path->nodes[0];
3985         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3986         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3987         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3988         if (ret) {
3989                 btrfs_abort_transaction(trans, root, ret);
3990                 goto out;
3991         }
3992         btrfs_release_path(path);
3993
3994         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3995                                  objectid, root->root_key.objectid,
3996                                  dir_ino, &index, name, name_len);
3997         if (ret < 0) {
3998                 if (ret != -ENOENT) {
3999                         btrfs_abort_transaction(trans, root, ret);
4000                         goto out;
4001                 }
4002                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4003                                                  name, name_len);
4004                 if (IS_ERR_OR_NULL(di)) {
4005                         if (!di)
4006                                 ret = -ENOENT;
4007                         else
4008                                 ret = PTR_ERR(di);
4009                         btrfs_abort_transaction(trans, root, ret);
4010                         goto out;
4011                 }
4012
4013                 leaf = path->nodes[0];
4014                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4015                 btrfs_release_path(path);
4016                 index = key.offset;
4017         }
4018         btrfs_release_path(path);
4019
4020         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4021         if (ret) {
4022                 btrfs_abort_transaction(trans, root, ret);
4023                 goto out;
4024         }
4025
4026         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4027         inode_inc_iversion(dir);
4028         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
4029         ret = btrfs_update_inode_fallback(trans, root, dir);
4030         if (ret)
4031                 btrfs_abort_transaction(trans, root, ret);
4032 out:
4033         btrfs_free_path(path);
4034         return ret;
4035 }
4036
4037 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4038 {
4039         struct inode *inode = dentry->d_inode;
4040         int err = 0;
4041         struct btrfs_root *root = BTRFS_I(dir)->root;
4042         struct btrfs_trans_handle *trans;
4043
4044         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4045                 return -ENOTEMPTY;
4046         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4047                 return -EPERM;
4048
4049         trans = __unlink_start_trans(dir);
4050         if (IS_ERR(trans))
4051                 return PTR_ERR(trans);
4052
4053         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4054                 err = btrfs_unlink_subvol(trans, root, dir,
4055                                           BTRFS_I(inode)->location.objectid,
4056                                           dentry->d_name.name,
4057                                           dentry->d_name.len);
4058                 goto out;
4059         }
4060
4061         err = btrfs_orphan_add(trans, inode);
4062         if (err)
4063                 goto out;
4064
4065         /* now the directory is empty */
4066         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
4067                                  dentry->d_name.name, dentry->d_name.len);
4068         if (!err)
4069                 btrfs_i_size_write(inode, 0);
4070 out:
4071         btrfs_end_transaction(trans, root);
4072         btrfs_btree_balance_dirty(root);
4073
4074         return err;
4075 }
4076
4077 /*
4078  * this can truncate away extent items, csum items and directory items.
4079  * It starts at a high offset and removes keys until it can't find
4080  * any higher than new_size
4081  *
4082  * csum items that cross the new i_size are truncated to the new size
4083  * as well.
4084  *
4085  * min_type is the minimum key type to truncate down to.  If set to 0, this
4086  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4087  */
4088 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4089                                struct btrfs_root *root,
4090                                struct inode *inode,
4091                                u64 new_size, u32 min_type)
4092 {
4093         struct btrfs_path *path;
4094         struct extent_buffer *leaf;
4095         struct btrfs_file_extent_item *fi;
4096         struct btrfs_key key;
4097         struct btrfs_key found_key;
4098         u64 extent_start = 0;
4099         u64 extent_num_bytes = 0;
4100         u64 extent_offset = 0;
4101         u64 item_end = 0;
4102         u64 last_size = (u64)-1;
4103         u32 found_type = (u8)-1;
4104         int found_extent;
4105         int del_item;
4106         int pending_del_nr = 0;
4107         int pending_del_slot = 0;
4108         int extent_type = -1;
4109         int ret;
4110         int err = 0;
4111         u64 ino = btrfs_ino(inode);
4112
4113         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4114
4115         path = btrfs_alloc_path();
4116         if (!path)
4117                 return -ENOMEM;
4118         path->reada = -1;
4119
4120         /*
4121          * We want to drop from the next block forward in case this new size is
4122          * not block aligned since we will be keeping the last block of the
4123          * extent just the way it is.
4124          */
4125         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4126             root == root->fs_info->tree_root)
4127                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4128                                         root->sectorsize), (u64)-1, 0);
4129
4130         /*
4131          * This function is also used to drop the items in the log tree before
4132          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4133          * it is used to drop the loged items. So we shouldn't kill the delayed
4134          * items.
4135          */
4136         if (min_type == 0 && root == BTRFS_I(inode)->root)
4137                 btrfs_kill_delayed_inode_items(inode);
4138
4139         key.objectid = ino;
4140         key.offset = (u64)-1;
4141         key.type = (u8)-1;
4142
4143 search_again:
4144         path->leave_spinning = 1;
4145         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4146         if (ret < 0) {
4147                 err = ret;
4148                 goto out;
4149         }
4150
4151         if (ret > 0) {
4152                 /* there are no items in the tree for us to truncate, we're
4153                  * done
4154                  */
4155                 if (path->slots[0] == 0)
4156                         goto out;
4157                 path->slots[0]--;
4158         }
4159
4160         while (1) {
4161                 fi = NULL;
4162                 leaf = path->nodes[0];
4163                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4164                 found_type = found_key.type;
4165
4166                 if (found_key.objectid != ino)
4167                         break;
4168
4169                 if (found_type < min_type)
4170                         break;
4171
4172                 item_end = found_key.offset;
4173                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4174                         fi = btrfs_item_ptr(leaf, path->slots[0],
4175                                             struct btrfs_file_extent_item);
4176                         extent_type = btrfs_file_extent_type(leaf, fi);
4177                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4178                                 item_end +=
4179                                     btrfs_file_extent_num_bytes(leaf, fi);
4180                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4181                                 item_end += btrfs_file_extent_inline_len(leaf,
4182                                                          path->slots[0], fi);
4183                         }
4184                         item_end--;
4185                 }
4186                 if (found_type > min_type) {
4187                         del_item = 1;
4188                 } else {
4189                         if (item_end < new_size)
4190                                 break;
4191                         if (found_key.offset >= new_size)
4192                                 del_item = 1;
4193                         else
4194                                 del_item = 0;
4195                 }
4196                 found_extent = 0;
4197                 /* FIXME, shrink the extent if the ref count is only 1 */
4198                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4199                         goto delete;
4200
4201                 if (del_item)
4202                         last_size = found_key.offset;
4203                 else
4204                         last_size = new_size;
4205
4206                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4207                         u64 num_dec;
4208                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4209                         if (!del_item) {
4210                                 u64 orig_num_bytes =
4211                                         btrfs_file_extent_num_bytes(leaf, fi);
4212                                 extent_num_bytes = ALIGN(new_size -
4213                                                 found_key.offset,
4214                                                 root->sectorsize);
4215                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4216                                                          extent_num_bytes);
4217                                 num_dec = (orig_num_bytes -
4218                                            extent_num_bytes);
4219                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4220                                              &root->state) &&
4221                                     extent_start != 0)
4222                                         inode_sub_bytes(inode, num_dec);
4223                                 btrfs_mark_buffer_dirty(leaf);
4224                         } else {
4225                                 extent_num_bytes =
4226                                         btrfs_file_extent_disk_num_bytes(leaf,
4227                                                                          fi);
4228                                 extent_offset = found_key.offset -
4229                                         btrfs_file_extent_offset(leaf, fi);
4230
4231                                 /* FIXME blocksize != 4096 */
4232                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4233                                 if (extent_start != 0) {
4234                                         found_extent = 1;
4235                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4236                                                      &root->state))
4237                                                 inode_sub_bytes(inode, num_dec);
4238                                 }
4239                         }
4240                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4241                         /*
4242                          * we can't truncate inline items that have had
4243                          * special encodings
4244                          */
4245                         if (!del_item &&
4246                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4247                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4248                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4249                                 u32 size = new_size - found_key.offset;
4250
4251                                 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4252                                         inode_sub_bytes(inode, item_end + 1 -
4253                                                         new_size);
4254
4255                                 /*
4256                                  * update the ram bytes to properly reflect
4257                                  * the new size of our item
4258                                  */
4259                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4260                                 size =
4261                                     btrfs_file_extent_calc_inline_size(size);
4262                                 btrfs_truncate_item(root, path, size, 1);
4263                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4264                                             &root->state)) {
4265                                 inode_sub_bytes(inode, item_end + 1 -
4266                                                 found_key.offset);
4267                         }
4268                 }
4269 delete:
4270                 if (del_item) {
4271                         if (!pending_del_nr) {
4272                                 /* no pending yet, add ourselves */
4273                                 pending_del_slot = path->slots[0];
4274                                 pending_del_nr = 1;
4275                         } else if (pending_del_nr &&
4276                                    path->slots[0] + 1 == pending_del_slot) {
4277                                 /* hop on the pending chunk */
4278                                 pending_del_nr++;
4279                                 pending_del_slot = path->slots[0];
4280                         } else {
4281                                 BUG();
4282                         }
4283                 } else {
4284                         break;
4285                 }
4286                 if (found_extent &&
4287                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4288                      root == root->fs_info->tree_root)) {
4289                         btrfs_set_path_blocking(path);
4290                         ret = btrfs_free_extent(trans, root, extent_start,
4291                                                 extent_num_bytes, 0,
4292                                                 btrfs_header_owner(leaf),
4293                                                 ino, extent_offset, 0);
4294                         BUG_ON(ret);
4295                 }
4296
4297                 if (found_type == BTRFS_INODE_ITEM_KEY)
4298                         break;
4299
4300                 if (path->slots[0] == 0 ||
4301                     path->slots[0] != pending_del_slot) {
4302                         if (pending_del_nr) {
4303                                 ret = btrfs_del_items(trans, root, path,
4304                                                 pending_del_slot,
4305                                                 pending_del_nr);
4306                                 if (ret) {
4307                                         btrfs_abort_transaction(trans,
4308                                                                 root, ret);
4309                                         goto error;
4310                                 }
4311                                 pending_del_nr = 0;
4312                         }
4313                         btrfs_release_path(path);
4314                         goto search_again;
4315                 } else {
4316                         path->slots[0]--;
4317                 }
4318         }
4319 out:
4320         if (pending_del_nr) {
4321                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4322                                       pending_del_nr);
4323                 if (ret)
4324                         btrfs_abort_transaction(trans, root, ret);
4325         }
4326 error:
4327         if (last_size != (u64)-1 &&
4328             root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4329                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4330         btrfs_free_path(path);
4331         return err;
4332 }
4333
4334 /*
4335  * btrfs_truncate_page - read, zero a chunk and write a page
4336  * @inode - inode that we're zeroing
4337  * @from - the offset to start zeroing
4338  * @len - the length to zero, 0 to zero the entire range respective to the
4339  *      offset
4340  * @front - zero up to the offset instead of from the offset on
4341  *
4342  * This will find the page for the "from" offset and cow the page and zero the
4343  * part we want to zero.  This is used with truncate and hole punching.
4344  */
4345 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4346                         int front)
4347 {
4348         struct address_space *mapping = inode->i_mapping;
4349         struct btrfs_root *root = BTRFS_I(inode)->root;
4350         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4351         struct btrfs_ordered_extent *ordered;
4352         struct extent_state *cached_state = NULL;
4353         char *kaddr;
4354         u32 blocksize = root->sectorsize;
4355         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4356         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4357         struct page *page;
4358         gfp_t mask = btrfs_alloc_write_mask(mapping);
4359         int ret = 0;
4360         u64 page_start;
4361         u64 page_end;
4362
4363         if ((offset & (blocksize - 1)) == 0 &&
4364             (!len || ((len & (blocksize - 1)) == 0)))
4365                 goto out;
4366         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4367         if (ret)
4368                 goto out;
4369
4370 again:
4371         page = find_or_create_page(mapping, index, mask);
4372         if (!page) {
4373                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4374                 ret = -ENOMEM;
4375                 goto out;
4376         }
4377
4378         page_start = page_offset(page);
4379         page_end = page_start + PAGE_CACHE_SIZE - 1;
4380
4381         if (!PageUptodate(page)) {
4382                 ret = btrfs_readpage(NULL, page);
4383                 lock_page(page);
4384                 if (page->mapping != mapping) {
4385                         unlock_page(page);
4386                         page_cache_release(page);
4387                         goto again;
4388                 }
4389                 if (!PageUptodate(page)) {
4390                         ret = -EIO;
4391                         goto out_unlock;
4392                 }
4393         }
4394         wait_on_page_writeback(page);
4395
4396         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4397         set_page_extent_mapped(page);
4398
4399         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4400         if (ordered) {
4401                 unlock_extent_cached(io_tree, page_start, page_end,
4402                                      &cached_state, GFP_NOFS);
4403                 unlock_page(page);
4404                 page_cache_release(page);
4405                 btrfs_start_ordered_extent(inode, ordered, 1);
4406                 btrfs_put_ordered_extent(ordered);
4407                 goto again;
4408         }
4409
4410         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4411                           EXTENT_DIRTY | EXTENT_DELALLOC |
4412                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4413                           0, 0, &cached_state, GFP_NOFS);
4414
4415         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4416                                         &cached_state);
4417         if (ret) {
4418                 unlock_extent_cached(io_tree, page_start, page_end,
4419                                      &cached_state, GFP_NOFS);
4420                 goto out_unlock;
4421         }
4422
4423         if (offset != PAGE_CACHE_SIZE) {
4424                 if (!len)
4425                         len = PAGE_CACHE_SIZE - offset;
4426                 kaddr = kmap(page);
4427                 if (front)
4428                         memset(kaddr, 0, offset);
4429                 else
4430                         memset(kaddr + offset, 0, len);
4431                 flush_dcache_page(page);
4432                 kunmap(page);
4433         }
4434         ClearPageChecked(page);
4435         set_page_dirty(page);
4436         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4437                              GFP_NOFS);
4438
4439 out_unlock:
4440         if (ret)
4441                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4442         unlock_page(page);
4443         page_cache_release(page);
4444 out:
4445         return ret;
4446 }
4447
4448 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4449                              u64 offset, u64 len)
4450 {
4451         struct btrfs_trans_handle *trans;
4452         int ret;
4453
4454         /*
4455          * Still need to make sure the inode looks like it's been updated so
4456          * that any holes get logged if we fsync.
4457          */
4458         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4459                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4460                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4461                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4462                 return 0;
4463         }
4464
4465         /*
4466          * 1 - for the one we're dropping
4467          * 1 - for the one we're adding
4468          * 1 - for updating the inode.
4469          */
4470         trans = btrfs_start_transaction(root, 3);
4471         if (IS_ERR(trans))
4472                 return PTR_ERR(trans);
4473
4474         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4475         if (ret) {
4476                 btrfs_abort_transaction(trans, root, ret);
4477                 btrfs_end_transaction(trans, root);
4478                 return ret;
4479         }
4480
4481         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4482                                        0, 0, len, 0, len, 0, 0, 0);
4483         if (ret)
4484                 btrfs_abort_transaction(trans, root, ret);
4485         else
4486                 btrfs_update_inode(trans, root, inode);
4487         btrfs_end_transaction(trans, root);
4488         return ret;
4489 }
4490
4491 /*
4492  * This function puts in dummy file extents for the area we're creating a hole
4493  * for.  So if we are truncating this file to a larger size we need to insert
4494  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4495  * the range between oldsize and size
4496  */
4497 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4498 {
4499         struct btrfs_root *root = BTRFS_I(inode)->root;
4500         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4501         struct extent_map *em = NULL;
4502         struct extent_state *cached_state = NULL;
4503         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4504         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4505         u64 block_end = ALIGN(size, root->sectorsize);
4506         u64 last_byte;
4507         u64 cur_offset;
4508         u64 hole_size;
4509         int err = 0;
4510
4511         /*
4512          * If our size started in the middle of a page we need to zero out the
4513          * rest of the page before we expand the i_size, otherwise we could
4514          * expose stale data.
4515          */
4516         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4517         if (err)
4518                 return err;
4519
4520         if (size <= hole_start)
4521                 return 0;
4522
4523         while (1) {
4524                 struct btrfs_ordered_extent *ordered;
4525
4526                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4527                                  &cached_state);
4528                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4529                                                      block_end - hole_start);
4530                 if (!ordered)
4531                         break;
4532                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4533                                      &cached_state, GFP_NOFS);
4534                 btrfs_start_ordered_extent(inode, ordered, 1);
4535                 btrfs_put_ordered_extent(ordered);
4536         }
4537
4538         cur_offset = hole_start;
4539         while (1) {
4540                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4541                                 block_end - cur_offset, 0);
4542                 if (IS_ERR(em)) {
4543                         err = PTR_ERR(em);
4544                         em = NULL;
4545                         break;
4546                 }
4547                 last_byte = min(extent_map_end(em), block_end);
4548                 last_byte = ALIGN(last_byte , root->sectorsize);
4549                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4550                         struct extent_map *hole_em;
4551                         hole_size = last_byte - cur_offset;
4552
4553                         err = maybe_insert_hole(root, inode, cur_offset,
4554                                                 hole_size);
4555                         if (err)
4556                                 break;
4557                         btrfs_drop_extent_cache(inode, cur_offset,
4558                                                 cur_offset + hole_size - 1, 0);
4559                         hole_em = alloc_extent_map();
4560                         if (!hole_em) {
4561                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4562                                         &BTRFS_I(inode)->runtime_flags);
4563                                 goto next;
4564                         }
4565                         hole_em->start = cur_offset;
4566                         hole_em->len = hole_size;
4567                         hole_em->orig_start = cur_offset;
4568
4569                         hole_em->block_start = EXTENT_MAP_HOLE;
4570                         hole_em->block_len = 0;
4571                         hole_em->orig_block_len = 0;
4572                         hole_em->ram_bytes = hole_size;
4573                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4574                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4575                         hole_em->generation = root->fs_info->generation;
4576
4577                         while (1) {
4578                                 write_lock(&em_tree->lock);
4579                                 err = add_extent_mapping(em_tree, hole_em, 1);
4580                                 write_unlock(&em_tree->lock);
4581                                 if (err != -EEXIST)
4582                                         break;
4583                                 btrfs_drop_extent_cache(inode, cur_offset,
4584                                                         cur_offset +
4585                                                         hole_size - 1, 0);
4586                         }
4587                         free_extent_map(hole_em);
4588                 }
4589 next:
4590                 free_extent_map(em);
4591                 em = NULL;
4592                 cur_offset = last_byte;
4593                 if (cur_offset >= block_end)
4594                         break;
4595         }
4596         free_extent_map(em);
4597         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4598                              GFP_NOFS);
4599         return err;
4600 }
4601
4602 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4603 {
4604         struct btrfs_root *root = BTRFS_I(inode)->root;
4605         struct btrfs_trans_handle *trans;
4606         loff_t oldsize = i_size_read(inode);
4607         loff_t newsize = attr->ia_size;
4608         int mask = attr->ia_valid;
4609         int ret;
4610
4611         /*
4612          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4613          * special case where we need to update the times despite not having
4614          * these flags set.  For all other operations the VFS set these flags
4615          * explicitly if it wants a timestamp update.
4616          */
4617         if (newsize != oldsize) {
4618                 inode_inc_iversion(inode);
4619                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4620                         inode->i_ctime = inode->i_mtime =
4621                                 current_fs_time(inode->i_sb);
4622         }
4623
4624         if (newsize > oldsize) {
4625                 truncate_pagecache(inode, newsize);
4626                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4627                 if (ret)
4628                         return ret;
4629
4630                 trans = btrfs_start_transaction(root, 1);
4631                 if (IS_ERR(trans))
4632                         return PTR_ERR(trans);
4633
4634                 i_size_write(inode, newsize);
4635                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4636                 ret = btrfs_update_inode(trans, root, inode);
4637                 btrfs_end_transaction(trans, root);
4638         } else {
4639
4640                 /*
4641                  * We're truncating a file that used to have good data down to
4642                  * zero. Make sure it gets into the ordered flush list so that
4643                  * any new writes get down to disk quickly.
4644                  */
4645                 if (newsize == 0)
4646                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4647                                 &BTRFS_I(inode)->runtime_flags);
4648
4649                 /*
4650                  * 1 for the orphan item we're going to add
4651                  * 1 for the orphan item deletion.
4652                  */
4653                 trans = btrfs_start_transaction(root, 2);
4654                 if (IS_ERR(trans))
4655                         return PTR_ERR(trans);
4656
4657                 /*
4658                  * We need to do this in case we fail at _any_ point during the
4659                  * actual truncate.  Once we do the truncate_setsize we could
4660                  * invalidate pages which forces any outstanding ordered io to
4661                  * be instantly completed which will give us extents that need
4662                  * to be truncated.  If we fail to get an orphan inode down we
4663                  * could have left over extents that were never meant to live,
4664                  * so we need to garuntee from this point on that everything
4665                  * will be consistent.
4666                  */
4667                 ret = btrfs_orphan_add(trans, inode);
4668                 btrfs_end_transaction(trans, root);
4669                 if (ret)
4670                         return ret;
4671
4672                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4673                 truncate_setsize(inode, newsize);
4674
4675                 /* Disable nonlocked read DIO to avoid the end less truncate */
4676                 btrfs_inode_block_unlocked_dio(inode);
4677                 inode_dio_wait(inode);
4678                 btrfs_inode_resume_unlocked_dio(inode);
4679
4680                 ret = btrfs_truncate(inode);
4681                 if (ret && inode->i_nlink) {
4682                         int err;
4683
4684                         /*
4685                          * failed to truncate, disk_i_size is only adjusted down
4686                          * as we remove extents, so it should represent the true
4687                          * size of the inode, so reset the in memory size and
4688                          * delete our orphan entry.
4689                          */
4690                         trans = btrfs_join_transaction(root);
4691                         if (IS_ERR(trans)) {
4692                                 btrfs_orphan_del(NULL, inode);
4693                                 return ret;
4694                         }
4695                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4696                         err = btrfs_orphan_del(trans, inode);
4697                         if (err)
4698                                 btrfs_abort_transaction(trans, root, err);
4699                         btrfs_end_transaction(trans, root);
4700                 }
4701         }
4702
4703         return ret;
4704 }
4705
4706 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4707 {
4708         struct inode *inode = dentry->d_inode;
4709         struct btrfs_root *root = BTRFS_I(inode)->root;
4710         int err;
4711
4712         if (btrfs_root_readonly(root))
4713                 return -EROFS;
4714
4715         err = inode_change_ok(inode, attr);
4716         if (err)
4717                 return err;
4718
4719         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4720                 err = btrfs_setsize(inode, attr);
4721                 if (err)
4722                         return err;
4723         }
4724
4725         if (attr->ia_valid) {
4726                 setattr_copy(inode, attr);
4727                 inode_inc_iversion(inode);
4728                 err = btrfs_dirty_inode(inode);
4729
4730                 if (!err && attr->ia_valid & ATTR_MODE)
4731                         err = posix_acl_chmod(inode, inode->i_mode);
4732         }
4733
4734         return err;
4735 }
4736
4737 /*
4738  * While truncating the inode pages during eviction, we get the VFS calling
4739  * btrfs_invalidatepage() against each page of the inode. This is slow because
4740  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4741  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4742  * extent_state structures over and over, wasting lots of time.
4743  *
4744  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4745  * those expensive operations on a per page basis and do only the ordered io
4746  * finishing, while we release here the extent_map and extent_state structures,
4747  * without the excessive merging and splitting.
4748  */
4749 static void evict_inode_truncate_pages(struct inode *inode)
4750 {
4751         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4752         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4753         struct rb_node *node;
4754
4755         ASSERT(inode->i_state & I_FREEING);
4756         truncate_inode_pages_final(&inode->i_data);
4757
4758         write_lock(&map_tree->lock);
4759         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4760                 struct extent_map *em;
4761
4762                 node = rb_first(&map_tree->map);
4763                 em = rb_entry(node, struct extent_map, rb_node);
4764                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4765                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4766                 remove_extent_mapping(map_tree, em);
4767                 free_extent_map(em);
4768                 if (need_resched()) {
4769                         write_unlock(&map_tree->lock);
4770                         cond_resched();
4771                         write_lock(&map_tree->lock);
4772                 }
4773         }
4774         write_unlock(&map_tree->lock);
4775
4776         spin_lock(&io_tree->lock);
4777         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4778                 struct extent_state *state;
4779                 struct extent_state *cached_state = NULL;
4780
4781                 node = rb_first(&io_tree->state);
4782                 state = rb_entry(node, struct extent_state, rb_node);
4783                 atomic_inc(&state->refs);
4784                 spin_unlock(&io_tree->lock);
4785
4786                 lock_extent_bits(io_tree, state->start, state->end,
4787                                  0, &cached_state);
4788                 clear_extent_bit(io_tree, state->start, state->end,
4789                                  EXTENT_LOCKED | EXTENT_DIRTY |
4790                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4791                                  EXTENT_DEFRAG, 1, 1,
4792                                  &cached_state, GFP_NOFS);
4793                 free_extent_state(state);
4794
4795                 cond_resched();
4796                 spin_lock(&io_tree->lock);
4797         }
4798         spin_unlock(&io_tree->lock);
4799 }
4800
4801 void btrfs_evict_inode(struct inode *inode)
4802 {
4803         struct btrfs_trans_handle *trans;
4804         struct btrfs_root *root = BTRFS_I(inode)->root;
4805         struct btrfs_block_rsv *rsv, *global_rsv;
4806         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4807         int ret;
4808
4809         trace_btrfs_inode_evict(inode);
4810
4811         evict_inode_truncate_pages(inode);
4812
4813         if (inode->i_nlink &&
4814             ((btrfs_root_refs(&root->root_item) != 0 &&
4815               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4816              btrfs_is_free_space_inode(inode)))
4817                 goto no_delete;
4818
4819         if (is_bad_inode(inode)) {
4820                 btrfs_orphan_del(NULL, inode);
4821                 goto no_delete;
4822         }
4823         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4824         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4825
4826         btrfs_free_io_failure_record(inode, 0, (u64)-1);
4827
4828         if (root->fs_info->log_root_recovering) {
4829                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4830                                  &BTRFS_I(inode)->runtime_flags));
4831                 goto no_delete;
4832         }
4833
4834         if (inode->i_nlink > 0) {
4835                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4836                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4837                 goto no_delete;
4838         }
4839
4840         ret = btrfs_commit_inode_delayed_inode(inode);
4841         if (ret) {
4842                 btrfs_orphan_del(NULL, inode);
4843                 goto no_delete;
4844         }
4845
4846         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4847         if (!rsv) {
4848                 btrfs_orphan_del(NULL, inode);
4849                 goto no_delete;
4850         }
4851         rsv->size = min_size;
4852         rsv->failfast = 1;
4853         global_rsv = &root->fs_info->global_block_rsv;
4854
4855         btrfs_i_size_write(inode, 0);
4856
4857         /*
4858          * This is a bit simpler than btrfs_truncate since we've already
4859          * reserved our space for our orphan item in the unlink, so we just
4860          * need to reserve some slack space in case we add bytes and update
4861          * inode item when doing the truncate.
4862          */
4863         while (1) {
4864                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4865                                              BTRFS_RESERVE_FLUSH_LIMIT);
4866
4867                 /*
4868                  * Try and steal from the global reserve since we will
4869                  * likely not use this space anyway, we want to try as
4870                  * hard as possible to get this to work.
4871                  */
4872                 if (ret)
4873                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4874
4875                 if (ret) {
4876                         btrfs_warn(root->fs_info,
4877                                 "Could not get space for a delete, will truncate on mount %d",
4878                                 ret);
4879                         btrfs_orphan_del(NULL, inode);
4880                         btrfs_free_block_rsv(root, rsv);
4881                         goto no_delete;
4882                 }
4883
4884                 trans = btrfs_join_transaction(root);
4885                 if (IS_ERR(trans)) {
4886                         btrfs_orphan_del(NULL, inode);
4887                         btrfs_free_block_rsv(root, rsv);
4888                         goto no_delete;
4889                 }
4890
4891                 trans->block_rsv = rsv;
4892
4893                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4894                 if (ret != -ENOSPC)
4895                         break;
4896
4897                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4898                 btrfs_end_transaction(trans, root);
4899                 trans = NULL;
4900                 btrfs_btree_balance_dirty(root);
4901         }
4902
4903         btrfs_free_block_rsv(root, rsv);
4904
4905         /*
4906          * Errors here aren't a big deal, it just means we leave orphan items
4907          * in the tree.  They will be cleaned up on the next mount.
4908          */
4909         if (ret == 0) {
4910                 trans->block_rsv = root->orphan_block_rsv;
4911                 btrfs_orphan_del(trans, inode);
4912         } else {
4913                 btrfs_orphan_del(NULL, inode);
4914         }
4915
4916         trans->block_rsv = &root->fs_info->trans_block_rsv;
4917         if (!(root == root->fs_info->tree_root ||
4918               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4919                 btrfs_return_ino(root, btrfs_ino(inode));
4920
4921         btrfs_end_transaction(trans, root);
4922         btrfs_btree_balance_dirty(root);
4923 no_delete:
4924         btrfs_remove_delayed_node(inode);
4925         clear_inode(inode);
4926         return;
4927 }
4928
4929 /*
4930  * this returns the key found in the dir entry in the location pointer.
4931  * If no dir entries were found, location->objectid is 0.
4932  */
4933 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4934                                struct btrfs_key *location)
4935 {
4936         const char *name = dentry->d_name.name;
4937         int namelen = dentry->d_name.len;
4938         struct btrfs_dir_item *di;
4939         struct btrfs_path *path;
4940         struct btrfs_root *root = BTRFS_I(dir)->root;
4941         int ret = 0;
4942
4943         path = btrfs_alloc_path();
4944         if (!path)
4945                 return -ENOMEM;
4946
4947         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4948                                     namelen, 0);
4949         if (IS_ERR(di))
4950                 ret = PTR_ERR(di);
4951
4952         if (IS_ERR_OR_NULL(di))
4953                 goto out_err;
4954
4955         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4956 out:
4957         btrfs_free_path(path);
4958         return ret;
4959 out_err:
4960         location->objectid = 0;
4961         goto out;
4962 }
4963
4964 /*
4965  * when we hit a tree root in a directory, the btrfs part of the inode
4966  * needs to be changed to reflect the root directory of the tree root.  This
4967  * is kind of like crossing a mount point.
4968  */
4969 static int fixup_tree_root_location(struct btrfs_root *root,
4970                                     struct inode *dir,
4971                                     struct dentry *dentry,
4972                                     struct btrfs_key *location,
4973                                     struct btrfs_root **sub_root)
4974 {
4975         struct btrfs_path *path;
4976         struct btrfs_root *new_root;
4977         struct btrfs_root_ref *ref;
4978         struct extent_buffer *leaf;
4979         int ret;
4980         int err = 0;
4981
4982         path = btrfs_alloc_path();
4983         if (!path) {
4984                 err = -ENOMEM;
4985                 goto out;
4986         }
4987
4988         err = -ENOENT;
4989         ret = btrfs_find_item(root->fs_info->tree_root, path,
4990                                 BTRFS_I(dir)->root->root_key.objectid,
4991                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4992         if (ret) {
4993                 if (ret < 0)
4994                         err = ret;
4995                 goto out;
4996         }
4997
4998         leaf = path->nodes[0];
4999         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5000         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5001             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5002                 goto out;
5003
5004         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5005                                    (unsigned long)(ref + 1),
5006                                    dentry->d_name.len);
5007         if (ret)
5008                 goto out;
5009
5010         btrfs_release_path(path);
5011
5012         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5013         if (IS_ERR(new_root)) {
5014                 err = PTR_ERR(new_root);
5015                 goto out;
5016         }
5017
5018         *sub_root = new_root;
5019         location->objectid = btrfs_root_dirid(&new_root->root_item);
5020         location->type = BTRFS_INODE_ITEM_KEY;
5021         location->offset = 0;
5022         err = 0;
5023 out:
5024         btrfs_free_path(path);
5025         return err;
5026 }
5027
5028 static void inode_tree_add(struct inode *inode)
5029 {
5030         struct btrfs_root *root = BTRFS_I(inode)->root;
5031         struct btrfs_inode *entry;
5032         struct rb_node **p;
5033         struct rb_node *parent;
5034         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5035         u64 ino = btrfs_ino(inode);
5036
5037         if (inode_unhashed(inode))
5038                 return;
5039         parent = NULL;
5040         spin_lock(&root->inode_lock);
5041         p = &root->inode_tree.rb_node;
5042         while (*p) {
5043                 parent = *p;
5044                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5045
5046                 if (ino < btrfs_ino(&entry->vfs_inode))
5047                         p = &parent->rb_left;
5048                 else if (ino > btrfs_ino(&entry->vfs_inode))
5049                         p = &parent->rb_right;
5050                 else {
5051                         WARN_ON(!(entry->vfs_inode.i_state &
5052                                   (I_WILL_FREE | I_FREEING)));
5053                         rb_replace_node(parent, new, &root->inode_tree);
5054                         RB_CLEAR_NODE(parent);
5055                         spin_unlock(&root->inode_lock);
5056                         return;
5057                 }
5058         }
5059         rb_link_node(new, parent, p);
5060         rb_insert_color(new, &root->inode_tree);
5061         spin_unlock(&root->inode_lock);
5062 }
5063
5064 static void inode_tree_del(struct inode *inode)
5065 {
5066         struct btrfs_root *root = BTRFS_I(inode)->root;
5067         int empty = 0;
5068
5069         spin_lock(&root->inode_lock);
5070         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5071                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5072                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5073                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5074         }
5075         spin_unlock(&root->inode_lock);
5076
5077         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5078                 synchronize_srcu(&root->fs_info->subvol_srcu);
5079                 spin_lock(&root->inode_lock);
5080                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5081                 spin_unlock(&root->inode_lock);
5082                 if (empty)
5083                         btrfs_add_dead_root(root);
5084         }
5085 }
5086
5087 void btrfs_invalidate_inodes(struct btrfs_root *root)
5088 {
5089         struct rb_node *node;
5090         struct rb_node *prev;
5091         struct btrfs_inode *entry;
5092         struct inode *inode;
5093         u64 objectid = 0;
5094
5095         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5096                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5097
5098         spin_lock(&root->inode_lock);
5099 again:
5100         node = root->inode_tree.rb_node;
5101         prev = NULL;
5102         while (node) {
5103                 prev = node;
5104                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5105
5106                 if (objectid < btrfs_ino(&entry->vfs_inode))
5107                         node = node->rb_left;
5108                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5109                         node = node->rb_right;
5110                 else
5111                         break;
5112         }
5113         if (!node) {
5114                 while (prev) {
5115                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5116                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5117                                 node = prev;
5118                                 break;
5119                         }
5120                         prev = rb_next(prev);
5121                 }
5122         }
5123         while (node) {
5124                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5125                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5126                 inode = igrab(&entry->vfs_inode);
5127                 if (inode) {
5128                         spin_unlock(&root->inode_lock);
5129                         if (atomic_read(&inode->i_count) > 1)
5130                                 d_prune_aliases(inode);
5131                         /*
5132                          * btrfs_drop_inode will have it removed from
5133                          * the inode cache when its usage count
5134                          * hits zero.
5135                          */
5136                         iput(inode);
5137                         cond_resched();
5138                         spin_lock(&root->inode_lock);
5139                         goto again;
5140                 }
5141
5142                 if (cond_resched_lock(&root->inode_lock))
5143                         goto again;
5144
5145                 node = rb_next(node);
5146         }
5147         spin_unlock(&root->inode_lock);
5148 }
5149
5150 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5151 {
5152         struct btrfs_iget_args *args = p;
5153         inode->i_ino = args->location->objectid;
5154         memcpy(&BTRFS_I(inode)->location, args->location,
5155                sizeof(*args->location));
5156         BTRFS_I(inode)->root = args->root;
5157         return 0;
5158 }
5159
5160 static int btrfs_find_actor(struct inode *inode, void *opaque)
5161 {
5162         struct btrfs_iget_args *args = opaque;
5163         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5164                 args->root == BTRFS_I(inode)->root;
5165 }
5166
5167 static struct inode *btrfs_iget_locked(struct super_block *s,
5168                                        struct btrfs_key *location,
5169                                        struct btrfs_root *root)
5170 {
5171         struct inode *inode;
5172         struct btrfs_iget_args args;
5173         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5174
5175         args.location = location;
5176         args.root = root;
5177
5178         inode = iget5_locked(s, hashval, btrfs_find_actor,
5179                              btrfs_init_locked_inode,
5180                              (void *)&args);
5181         return inode;
5182 }
5183
5184 /* Get an inode object given its location and corresponding root.
5185  * Returns in *is_new if the inode was read from disk
5186  */
5187 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5188                          struct btrfs_root *root, int *new)
5189 {
5190         struct inode *inode;
5191
5192         inode = btrfs_iget_locked(s, location, root);
5193         if (!inode)
5194                 return ERR_PTR(-ENOMEM);
5195
5196         if (inode->i_state & I_NEW) {
5197                 btrfs_read_locked_inode(inode);
5198                 if (!is_bad_inode(inode)) {
5199                         inode_tree_add(inode);
5200                         unlock_new_inode(inode);
5201                         if (new)
5202                                 *new = 1;
5203                 } else {
5204                         unlock_new_inode(inode);
5205                         iput(inode);
5206                         inode = ERR_PTR(-ESTALE);
5207                 }
5208         }
5209
5210         return inode;
5211 }
5212
5213 static struct inode *new_simple_dir(struct super_block *s,
5214                                     struct btrfs_key *key,
5215                                     struct btrfs_root *root)
5216 {
5217         struct inode *inode = new_inode(s);
5218
5219         if (!inode)
5220                 return ERR_PTR(-ENOMEM);
5221
5222         BTRFS_I(inode)->root = root;
5223         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5224         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5225
5226         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5227         inode->i_op = &btrfs_dir_ro_inode_operations;
5228         inode->i_fop = &simple_dir_operations;
5229         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5230         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5231
5232         return inode;
5233 }
5234
5235 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5236 {
5237         struct inode *inode;
5238         struct btrfs_root *root = BTRFS_I(dir)->root;
5239         struct btrfs_root *sub_root = root;
5240         struct btrfs_key location;
5241         int index;
5242         int ret = 0;
5243
5244         if (dentry->d_name.len > BTRFS_NAME_LEN)
5245                 return ERR_PTR(-ENAMETOOLONG);
5246
5247         ret = btrfs_inode_by_name(dir, dentry, &location);
5248         if (ret < 0)
5249                 return ERR_PTR(ret);
5250
5251         if (location.objectid == 0)
5252                 return ERR_PTR(-ENOENT);
5253
5254         if (location.type == BTRFS_INODE_ITEM_KEY) {
5255                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5256                 return inode;
5257         }
5258
5259         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5260
5261         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5262         ret = fixup_tree_root_location(root, dir, dentry,
5263                                        &location, &sub_root);
5264         if (ret < 0) {
5265                 if (ret != -ENOENT)
5266                         inode = ERR_PTR(ret);
5267                 else
5268                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5269         } else {
5270                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5271         }
5272         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5273
5274         if (!IS_ERR(inode) && root != sub_root) {
5275                 down_read(&root->fs_info->cleanup_work_sem);
5276                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5277                         ret = btrfs_orphan_cleanup(sub_root);
5278                 up_read(&root->fs_info->cleanup_work_sem);
5279                 if (ret) {
5280                         iput(inode);
5281                         inode = ERR_PTR(ret);
5282                 }
5283         }
5284
5285         return inode;
5286 }
5287
5288 static int btrfs_dentry_delete(const struct dentry *dentry)
5289 {
5290         struct btrfs_root *root;
5291         struct inode *inode = dentry->d_inode;
5292
5293         if (!inode && !IS_ROOT(dentry))
5294                 inode = dentry->d_parent->d_inode;
5295
5296         if (inode) {
5297                 root = BTRFS_I(inode)->root;
5298                 if (btrfs_root_refs(&root->root_item) == 0)
5299                         return 1;
5300
5301                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5302                         return 1;
5303         }
5304         return 0;
5305 }
5306
5307 static void btrfs_dentry_release(struct dentry *dentry)
5308 {
5309         kfree(dentry->d_fsdata);
5310 }
5311
5312 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5313                                    unsigned int flags)
5314 {
5315         struct inode *inode;
5316
5317         inode = btrfs_lookup_dentry(dir, dentry);
5318         if (IS_ERR(inode)) {
5319                 if (PTR_ERR(inode) == -ENOENT)
5320                         inode = NULL;
5321                 else
5322                         return ERR_CAST(inode);
5323         }
5324
5325         return d_materialise_unique(dentry, inode);
5326 }
5327
5328 unsigned char btrfs_filetype_table[] = {
5329         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5330 };
5331
5332 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5333 {
5334         struct inode *inode = file_inode(file);
5335         struct btrfs_root *root = BTRFS_I(inode)->root;
5336         struct btrfs_item *item;
5337         struct btrfs_dir_item *di;
5338         struct btrfs_key key;
5339         struct btrfs_key found_key;
5340         struct btrfs_path *path;
5341         struct list_head ins_list;
5342         struct list_head del_list;
5343         int ret;
5344         struct extent_buffer *leaf;
5345         int slot;
5346         unsigned char d_type;
5347         int over = 0;
5348         u32 di_cur;
5349         u32 di_total;
5350         u32 di_len;
5351         int key_type = BTRFS_DIR_INDEX_KEY;
5352         char tmp_name[32];
5353         char *name_ptr;
5354         int name_len;
5355         int is_curr = 0;        /* ctx->pos points to the current index? */
5356
5357         /* FIXME, use a real flag for deciding about the key type */
5358         if (root->fs_info->tree_root == root)
5359                 key_type = BTRFS_DIR_ITEM_KEY;
5360
5361         if (!dir_emit_dots(file, ctx))
5362                 return 0;
5363
5364         path = btrfs_alloc_path();
5365         if (!path)
5366                 return -ENOMEM;
5367
5368         path->reada = 1;
5369
5370         if (key_type == BTRFS_DIR_INDEX_KEY) {
5371                 INIT_LIST_HEAD(&ins_list);
5372                 INIT_LIST_HEAD(&del_list);
5373                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5374         }
5375
5376         key.type = key_type;
5377         key.offset = ctx->pos;
5378         key.objectid = btrfs_ino(inode);
5379
5380         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5381         if (ret < 0)
5382                 goto err;
5383
5384         while (1) {
5385                 leaf = path->nodes[0];
5386                 slot = path->slots[0];
5387                 if (slot >= btrfs_header_nritems(leaf)) {
5388                         ret = btrfs_next_leaf(root, path);
5389                         if (ret < 0)
5390                                 goto err;
5391                         else if (ret > 0)
5392                                 break;
5393                         continue;
5394                 }
5395
5396                 item = btrfs_item_nr(slot);
5397                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5398
5399                 if (found_key.objectid != key.objectid)
5400                         break;
5401                 if (found_key.type != key_type)
5402                         break;
5403                 if (found_key.offset < ctx->pos)
5404                         goto next;
5405                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5406                     btrfs_should_delete_dir_index(&del_list,
5407                                                   found_key.offset))
5408                         goto next;
5409
5410                 ctx->pos = found_key.offset;
5411                 is_curr = 1;
5412
5413                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5414                 di_cur = 0;
5415                 di_total = btrfs_item_size(leaf, item);
5416
5417                 while (di_cur < di_total) {
5418                         struct btrfs_key location;
5419
5420                         if (verify_dir_item(root, leaf, di))
5421                                 break;
5422
5423                         name_len = btrfs_dir_name_len(leaf, di);
5424                         if (name_len <= sizeof(tmp_name)) {
5425                                 name_ptr = tmp_name;
5426                         } else {
5427                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5428                                 if (!name_ptr) {
5429                                         ret = -ENOMEM;
5430                                         goto err;
5431                                 }
5432                         }
5433                         read_extent_buffer(leaf, name_ptr,
5434                                            (unsigned long)(di + 1), name_len);
5435
5436                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5437                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5438
5439
5440                         /* is this a reference to our own snapshot? If so
5441                          * skip it.
5442                          *
5443                          * In contrast to old kernels, we insert the snapshot's
5444                          * dir item and dir index after it has been created, so
5445                          * we won't find a reference to our own snapshot. We
5446                          * still keep the following code for backward
5447                          * compatibility.
5448                          */
5449                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5450                             location.objectid == root->root_key.objectid) {
5451                                 over = 0;
5452                                 goto skip;
5453                         }
5454                         over = !dir_emit(ctx, name_ptr, name_len,
5455                                        location.objectid, d_type);
5456
5457 skip:
5458                         if (name_ptr != tmp_name)
5459                                 kfree(name_ptr);
5460
5461                         if (over)
5462                                 goto nopos;
5463                         di_len = btrfs_dir_name_len(leaf, di) +
5464                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5465                         di_cur += di_len;
5466                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5467                 }
5468 next:
5469                 path->slots[0]++;
5470         }
5471
5472         if (key_type == BTRFS_DIR_INDEX_KEY) {
5473                 if (is_curr)
5474                         ctx->pos++;
5475                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5476                 if (ret)
5477                         goto nopos;
5478         }
5479
5480         /* Reached end of directory/root. Bump pos past the last item. */
5481         ctx->pos++;
5482
5483         /*
5484          * Stop new entries from being returned after we return the last
5485          * entry.
5486          *
5487          * New directory entries are assigned a strictly increasing
5488          * offset.  This means that new entries created during readdir
5489          * are *guaranteed* to be seen in the future by that readdir.
5490          * This has broken buggy programs which operate on names as
5491          * they're returned by readdir.  Until we re-use freed offsets
5492          * we have this hack to stop new entries from being returned
5493          * under the assumption that they'll never reach this huge
5494          * offset.
5495          *
5496          * This is being careful not to overflow 32bit loff_t unless the
5497          * last entry requires it because doing so has broken 32bit apps
5498          * in the past.
5499          */
5500         if (key_type == BTRFS_DIR_INDEX_KEY) {
5501                 if (ctx->pos >= INT_MAX)
5502                         ctx->pos = LLONG_MAX;
5503                 else
5504                         ctx->pos = INT_MAX;
5505         }
5506 nopos:
5507         ret = 0;
5508 err:
5509         if (key_type == BTRFS_DIR_INDEX_KEY)
5510                 btrfs_put_delayed_items(&ins_list, &del_list);
5511         btrfs_free_path(path);
5512         return ret;
5513 }
5514
5515 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5516 {
5517         struct btrfs_root *root = BTRFS_I(inode)->root;
5518         struct btrfs_trans_handle *trans;
5519         int ret = 0;
5520         bool nolock = false;
5521
5522         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5523                 return 0;
5524
5525         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5526                 nolock = true;
5527
5528         if (wbc->sync_mode == WB_SYNC_ALL) {
5529                 if (nolock)
5530                         trans = btrfs_join_transaction_nolock(root);
5531                 else
5532                         trans = btrfs_join_transaction(root);
5533                 if (IS_ERR(trans))
5534                         return PTR_ERR(trans);
5535                 ret = btrfs_commit_transaction(trans, root);
5536         }
5537         return ret;
5538 }
5539
5540 /*
5541  * This is somewhat expensive, updating the tree every time the
5542  * inode changes.  But, it is most likely to find the inode in cache.
5543  * FIXME, needs more benchmarking...there are no reasons other than performance
5544  * to keep or drop this code.
5545  */
5546 static int btrfs_dirty_inode(struct inode *inode)
5547 {
5548         struct btrfs_root *root = BTRFS_I(inode)->root;
5549         struct btrfs_trans_handle *trans;
5550         int ret;
5551
5552         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5553                 return 0;
5554
5555         trans = btrfs_join_transaction(root);
5556         if (IS_ERR(trans))
5557                 return PTR_ERR(trans);
5558
5559         ret = btrfs_update_inode(trans, root, inode);
5560         if (ret && ret == -ENOSPC) {
5561                 /* whoops, lets try again with the full transaction */
5562                 btrfs_end_transaction(trans, root);
5563                 trans = btrfs_start_transaction(root, 1);
5564                 if (IS_ERR(trans))
5565                         return PTR_ERR(trans);
5566
5567                 ret = btrfs_update_inode(trans, root, inode);
5568         }
5569         btrfs_end_transaction(trans, root);
5570         if (BTRFS_I(inode)->delayed_node)
5571                 btrfs_balance_delayed_items(root);
5572
5573         return ret;
5574 }
5575
5576 /*
5577  * This is a copy of file_update_time.  We need this so we can return error on
5578  * ENOSPC for updating the inode in the case of file write and mmap writes.
5579  */
5580 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5581                              int flags)
5582 {
5583         struct btrfs_root *root = BTRFS_I(inode)->root;
5584
5585         if (btrfs_root_readonly(root))
5586                 return -EROFS;
5587
5588         if (flags & S_VERSION)
5589                 inode_inc_iversion(inode);
5590         if (flags & S_CTIME)
5591                 inode->i_ctime = *now;
5592         if (flags & S_MTIME)
5593                 inode->i_mtime = *now;
5594         if (flags & S_ATIME)
5595                 inode->i_atime = *now;
5596         return btrfs_dirty_inode(inode);
5597 }
5598
5599 /*
5600  * find the highest existing sequence number in a directory
5601  * and then set the in-memory index_cnt variable to reflect
5602  * free sequence numbers
5603  */
5604 static int btrfs_set_inode_index_count(struct inode *inode)
5605 {
5606         struct btrfs_root *root = BTRFS_I(inode)->root;
5607         struct btrfs_key key, found_key;
5608         struct btrfs_path *path;
5609         struct extent_buffer *leaf;
5610         int ret;
5611
5612         key.objectid = btrfs_ino(inode);
5613         key.type = BTRFS_DIR_INDEX_KEY;
5614         key.offset = (u64)-1;
5615
5616         path = btrfs_alloc_path();
5617         if (!path)
5618                 return -ENOMEM;
5619
5620         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5621         if (ret < 0)
5622                 goto out;
5623         /* FIXME: we should be able to handle this */
5624         if (ret == 0)
5625                 goto out;
5626         ret = 0;
5627
5628         /*
5629          * MAGIC NUMBER EXPLANATION:
5630          * since we search a directory based on f_pos we have to start at 2
5631          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5632          * else has to start at 2
5633          */
5634         if (path->slots[0] == 0) {
5635                 BTRFS_I(inode)->index_cnt = 2;
5636                 goto out;
5637         }
5638
5639         path->slots[0]--;
5640
5641         leaf = path->nodes[0];
5642         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5643
5644         if (found_key.objectid != btrfs_ino(inode) ||
5645             found_key.type != BTRFS_DIR_INDEX_KEY) {
5646                 BTRFS_I(inode)->index_cnt = 2;
5647                 goto out;
5648         }
5649
5650         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5651 out:
5652         btrfs_free_path(path);
5653         return ret;
5654 }
5655
5656 /*
5657  * helper to find a free sequence number in a given directory.  This current
5658  * code is very simple, later versions will do smarter things in the btree
5659  */
5660 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5661 {
5662         int ret = 0;
5663
5664         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5665                 ret = btrfs_inode_delayed_dir_index_count(dir);
5666                 if (ret) {
5667                         ret = btrfs_set_inode_index_count(dir);
5668                         if (ret)
5669                                 return ret;
5670                 }
5671         }
5672
5673         *index = BTRFS_I(dir)->index_cnt;
5674         BTRFS_I(dir)->index_cnt++;
5675
5676         return ret;
5677 }
5678
5679 static int btrfs_insert_inode_locked(struct inode *inode)
5680 {
5681         struct btrfs_iget_args args;
5682         args.location = &BTRFS_I(inode)->location;
5683         args.root = BTRFS_I(inode)->root;
5684
5685         return insert_inode_locked4(inode,
5686                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
5687                    btrfs_find_actor, &args);
5688 }
5689
5690 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5691                                      struct btrfs_root *root,
5692                                      struct inode *dir,
5693                                      const char *name, int name_len,
5694                                      u64 ref_objectid, u64 objectid,
5695                                      umode_t mode, u64 *index)
5696 {
5697         struct inode *inode;
5698         struct btrfs_inode_item *inode_item;
5699         struct btrfs_key *location;
5700         struct btrfs_path *path;
5701         struct btrfs_inode_ref *ref;
5702         struct btrfs_key key[2];
5703         u32 sizes[2];
5704         int nitems = name ? 2 : 1;
5705         unsigned long ptr;
5706         int ret;
5707
5708         path = btrfs_alloc_path();
5709         if (!path)
5710                 return ERR_PTR(-ENOMEM);
5711
5712         inode = new_inode(root->fs_info->sb);
5713         if (!inode) {
5714                 btrfs_free_path(path);
5715                 return ERR_PTR(-ENOMEM);
5716         }
5717
5718         /*
5719          * O_TMPFILE, set link count to 0, so that after this point,
5720          * we fill in an inode item with the correct link count.
5721          */
5722         if (!name)
5723                 set_nlink(inode, 0);
5724
5725         /*
5726          * we have to initialize this early, so we can reclaim the inode
5727          * number if we fail afterwards in this function.
5728          */
5729         inode->i_ino = objectid;
5730
5731         if (dir && name) {
5732                 trace_btrfs_inode_request(dir);
5733
5734                 ret = btrfs_set_inode_index(dir, index);
5735                 if (ret) {
5736                         btrfs_free_path(path);
5737                         iput(inode);
5738                         return ERR_PTR(ret);
5739                 }
5740         } else if (dir) {
5741                 *index = 0;
5742         }
5743         /*
5744          * index_cnt is ignored for everything but a dir,
5745          * btrfs_get_inode_index_count has an explanation for the magic
5746          * number
5747          */
5748         BTRFS_I(inode)->index_cnt = 2;
5749         BTRFS_I(inode)->dir_index = *index;
5750         BTRFS_I(inode)->root = root;
5751         BTRFS_I(inode)->generation = trans->transid;
5752         inode->i_generation = BTRFS_I(inode)->generation;
5753
5754         /*
5755          * We could have gotten an inode number from somebody who was fsynced
5756          * and then removed in this same transaction, so let's just set full
5757          * sync since it will be a full sync anyway and this will blow away the
5758          * old info in the log.
5759          */
5760         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5761
5762         key[0].objectid = objectid;
5763         key[0].type = BTRFS_INODE_ITEM_KEY;
5764         key[0].offset = 0;
5765
5766         sizes[0] = sizeof(struct btrfs_inode_item);
5767
5768         if (name) {
5769                 /*
5770                  * Start new inodes with an inode_ref. This is slightly more
5771                  * efficient for small numbers of hard links since they will
5772                  * be packed into one item. Extended refs will kick in if we
5773                  * add more hard links than can fit in the ref item.
5774                  */
5775                 key[1].objectid = objectid;
5776                 key[1].type = BTRFS_INODE_REF_KEY;
5777                 key[1].offset = ref_objectid;
5778
5779                 sizes[1] = name_len + sizeof(*ref);
5780         }
5781
5782         location = &BTRFS_I(inode)->location;
5783         location->objectid = objectid;
5784         location->offset = 0;
5785         location->type = BTRFS_INODE_ITEM_KEY;
5786
5787         ret = btrfs_insert_inode_locked(inode);
5788         if (ret < 0)
5789                 goto fail;
5790
5791         path->leave_spinning = 1;
5792         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
5793         if (ret != 0)
5794                 goto fail_unlock;
5795
5796         inode_init_owner(inode, dir, mode);
5797         inode_set_bytes(inode, 0);
5798         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5799         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5800                                   struct btrfs_inode_item);
5801         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5802                              sizeof(*inode_item));
5803         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5804
5805         if (name) {
5806                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5807                                      struct btrfs_inode_ref);
5808                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5809                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5810                 ptr = (unsigned long)(ref + 1);
5811                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
5812         }
5813
5814         btrfs_mark_buffer_dirty(path->nodes[0]);
5815         btrfs_free_path(path);
5816
5817         btrfs_inherit_iflags(inode, dir);
5818
5819         if (S_ISREG(mode)) {
5820                 if (btrfs_test_opt(root, NODATASUM))
5821                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5822                 if (btrfs_test_opt(root, NODATACOW))
5823                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5824                                 BTRFS_INODE_NODATASUM;
5825         }
5826
5827         inode_tree_add(inode);
5828
5829         trace_btrfs_inode_new(inode);
5830         btrfs_set_inode_last_trans(trans, inode);
5831
5832         btrfs_update_root_times(trans, root);
5833
5834         ret = btrfs_inode_inherit_props(trans, inode, dir);
5835         if (ret)
5836                 btrfs_err(root->fs_info,
5837                           "error inheriting props for ino %llu (root %llu): %d",
5838                           btrfs_ino(inode), root->root_key.objectid, ret);
5839
5840         return inode;
5841
5842 fail_unlock:
5843         unlock_new_inode(inode);
5844 fail:
5845         if (dir && name)
5846                 BTRFS_I(dir)->index_cnt--;
5847         btrfs_free_path(path);
5848         iput(inode);
5849         return ERR_PTR(ret);
5850 }
5851
5852 static inline u8 btrfs_inode_type(struct inode *inode)
5853 {
5854         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5855 }
5856
5857 /*
5858  * utility function to add 'inode' into 'parent_inode' with
5859  * a give name and a given sequence number.
5860  * if 'add_backref' is true, also insert a backref from the
5861  * inode to the parent directory.
5862  */
5863 int btrfs_add_link(struct btrfs_trans_handle *trans,
5864                    struct inode *parent_inode, struct inode *inode,
5865                    const char *name, int name_len, int add_backref, u64 index)
5866 {
5867         int ret = 0;
5868         struct btrfs_key key;
5869         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5870         u64 ino = btrfs_ino(inode);
5871         u64 parent_ino = btrfs_ino(parent_inode);
5872
5873         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5874                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5875         } else {
5876                 key.objectid = ino;
5877                 key.type = BTRFS_INODE_ITEM_KEY;
5878                 key.offset = 0;
5879         }
5880
5881         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5882                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5883                                          key.objectid, root->root_key.objectid,
5884                                          parent_ino, index, name, name_len);
5885         } else if (add_backref) {
5886                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5887                                              parent_ino, index);
5888         }
5889
5890         /* Nothing to clean up yet */
5891         if (ret)
5892                 return ret;
5893
5894         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5895                                     parent_inode, &key,
5896                                     btrfs_inode_type(inode), index);
5897         if (ret == -EEXIST || ret == -EOVERFLOW)
5898                 goto fail_dir_item;
5899         else if (ret) {
5900                 btrfs_abort_transaction(trans, root, ret);
5901                 return ret;
5902         }
5903
5904         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5905                            name_len * 2);
5906         inode_inc_iversion(parent_inode);
5907         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5908         ret = btrfs_update_inode(trans, root, parent_inode);
5909         if (ret)
5910                 btrfs_abort_transaction(trans, root, ret);
5911         return ret;
5912
5913 fail_dir_item:
5914         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5915                 u64 local_index;
5916                 int err;
5917                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5918                                  key.objectid, root->root_key.objectid,
5919                                  parent_ino, &local_index, name, name_len);
5920
5921         } else if (add_backref) {
5922                 u64 local_index;
5923                 int err;
5924
5925                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5926                                           ino, parent_ino, &local_index);
5927         }
5928         return ret;
5929 }
5930
5931 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5932                             struct inode *dir, struct dentry *dentry,
5933                             struct inode *inode, int backref, u64 index)
5934 {
5935         int err = btrfs_add_link(trans, dir, inode,
5936                                  dentry->d_name.name, dentry->d_name.len,
5937                                  backref, index);
5938         if (err > 0)
5939                 err = -EEXIST;
5940         return err;
5941 }
5942
5943 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5944                         umode_t mode, dev_t rdev)
5945 {
5946         struct btrfs_trans_handle *trans;
5947         struct btrfs_root *root = BTRFS_I(dir)->root;
5948         struct inode *inode = NULL;
5949         int err;
5950         int drop_inode = 0;
5951         u64 objectid;
5952         u64 index = 0;
5953
5954         if (!new_valid_dev(rdev))
5955                 return -EINVAL;
5956
5957         /*
5958          * 2 for inode item and ref
5959          * 2 for dir items
5960          * 1 for xattr if selinux is on
5961          */
5962         trans = btrfs_start_transaction(root, 5);
5963         if (IS_ERR(trans))
5964                 return PTR_ERR(trans);
5965
5966         err = btrfs_find_free_ino(root, &objectid);
5967         if (err)
5968                 goto out_unlock;
5969
5970         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5971                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5972                                 mode, &index);
5973         if (IS_ERR(inode)) {
5974                 err = PTR_ERR(inode);
5975                 goto out_unlock;
5976         }
5977
5978         /*
5979         * If the active LSM wants to access the inode during
5980         * d_instantiate it needs these. Smack checks to see
5981         * if the filesystem supports xattrs by looking at the
5982         * ops vector.
5983         */
5984         inode->i_op = &btrfs_special_inode_operations;
5985         init_special_inode(inode, inode->i_mode, rdev);
5986
5987         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5988         if (err)
5989                 goto out_unlock_inode;
5990
5991         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5992         if (err) {
5993                 goto out_unlock_inode;
5994         } else {
5995                 btrfs_update_inode(trans, root, inode);
5996                 unlock_new_inode(inode);
5997                 d_instantiate(dentry, inode);
5998         }
5999
6000 out_unlock:
6001         btrfs_end_transaction(trans, root);
6002         btrfs_balance_delayed_items(root);
6003         btrfs_btree_balance_dirty(root);
6004         if (drop_inode) {
6005                 inode_dec_link_count(inode);
6006                 iput(inode);
6007         }
6008         return err;
6009
6010 out_unlock_inode:
6011         drop_inode = 1;
6012         unlock_new_inode(inode);
6013         goto out_unlock;
6014
6015 }
6016
6017 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6018                         umode_t mode, bool excl)
6019 {
6020         struct btrfs_trans_handle *trans;
6021         struct btrfs_root *root = BTRFS_I(dir)->root;
6022         struct inode *inode = NULL;
6023         int drop_inode_on_err = 0;
6024         int err;
6025         u64 objectid;
6026         u64 index = 0;
6027
6028         /*
6029          * 2 for inode item and ref
6030          * 2 for dir items
6031          * 1 for xattr if selinux is on
6032          */
6033         trans = btrfs_start_transaction(root, 5);
6034         if (IS_ERR(trans))
6035                 return PTR_ERR(trans);
6036
6037         err = btrfs_find_free_ino(root, &objectid);
6038         if (err)
6039                 goto out_unlock;
6040
6041         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6042                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6043                                 mode, &index);
6044         if (IS_ERR(inode)) {
6045                 err = PTR_ERR(inode);
6046                 goto out_unlock;
6047         }
6048         drop_inode_on_err = 1;
6049         /*
6050         * If the active LSM wants to access the inode during
6051         * d_instantiate it needs these. Smack checks to see
6052         * if the filesystem supports xattrs by looking at the
6053         * ops vector.
6054         */
6055         inode->i_fop = &btrfs_file_operations;
6056         inode->i_op = &btrfs_file_inode_operations;
6057         inode->i_mapping->a_ops = &btrfs_aops;
6058         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
6059
6060         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6061         if (err)
6062                 goto out_unlock_inode;
6063
6064         err = btrfs_update_inode(trans, root, inode);
6065         if (err)
6066                 goto out_unlock_inode;
6067
6068         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6069         if (err)
6070                 goto out_unlock_inode;
6071
6072         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6073         unlock_new_inode(inode);
6074         d_instantiate(dentry, inode);
6075
6076 out_unlock:
6077         btrfs_end_transaction(trans, root);
6078         if (err && drop_inode_on_err) {
6079                 inode_dec_link_count(inode);
6080                 iput(inode);
6081         }
6082         btrfs_balance_delayed_items(root);
6083         btrfs_btree_balance_dirty(root);
6084         return err;
6085
6086 out_unlock_inode:
6087         unlock_new_inode(inode);
6088         goto out_unlock;
6089
6090 }
6091
6092 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6093                       struct dentry *dentry)
6094 {
6095         struct btrfs_trans_handle *trans;
6096         struct btrfs_root *root = BTRFS_I(dir)->root;
6097         struct inode *inode = old_dentry->d_inode;
6098         u64 index;
6099         int err;
6100         int drop_inode = 0;
6101
6102         /* do not allow sys_link's with other subvols of the same device */
6103         if (root->objectid != BTRFS_I(inode)->root->objectid)
6104                 return -EXDEV;
6105
6106         if (inode->i_nlink >= BTRFS_LINK_MAX)
6107                 return -EMLINK;
6108
6109         err = btrfs_set_inode_index(dir, &index);
6110         if (err)
6111                 goto fail;
6112
6113         /*
6114          * 2 items for inode and inode ref
6115          * 2 items for dir items
6116          * 1 item for parent inode
6117          */
6118         trans = btrfs_start_transaction(root, 5);
6119         if (IS_ERR(trans)) {
6120                 err = PTR_ERR(trans);
6121                 goto fail;
6122         }
6123
6124         /* There are several dir indexes for this inode, clear the cache. */
6125         BTRFS_I(inode)->dir_index = 0ULL;
6126         inc_nlink(inode);
6127         inode_inc_iversion(inode);
6128         inode->i_ctime = CURRENT_TIME;
6129         ihold(inode);
6130         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6131
6132         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6133
6134         if (err) {
6135                 drop_inode = 1;
6136         } else {
6137                 struct dentry *parent = dentry->d_parent;
6138                 err = btrfs_update_inode(trans, root, inode);
6139                 if (err)
6140                         goto fail;
6141                 if (inode->i_nlink == 1) {
6142                         /*
6143                          * If new hard link count is 1, it's a file created
6144                          * with open(2) O_TMPFILE flag.
6145                          */
6146                         err = btrfs_orphan_del(trans, inode);
6147                         if (err)
6148                                 goto fail;
6149                 }
6150                 d_instantiate(dentry, inode);
6151                 btrfs_log_new_name(trans, inode, NULL, parent);
6152         }
6153
6154         btrfs_end_transaction(trans, root);
6155         btrfs_balance_delayed_items(root);
6156 fail:
6157         if (drop_inode) {
6158                 inode_dec_link_count(inode);
6159                 iput(inode);
6160         }
6161         btrfs_btree_balance_dirty(root);
6162         return err;
6163 }
6164
6165 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6166 {
6167         struct inode *inode = NULL;
6168         struct btrfs_trans_handle *trans;
6169         struct btrfs_root *root = BTRFS_I(dir)->root;
6170         int err = 0;
6171         int drop_on_err = 0;
6172         u64 objectid = 0;
6173         u64 index = 0;
6174
6175         /*
6176          * 2 items for inode and ref
6177          * 2 items for dir items
6178          * 1 for xattr if selinux is on
6179          */
6180         trans = btrfs_start_transaction(root, 5);
6181         if (IS_ERR(trans))
6182                 return PTR_ERR(trans);
6183
6184         err = btrfs_find_free_ino(root, &objectid);
6185         if (err)
6186                 goto out_fail;
6187
6188         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6189                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6190                                 S_IFDIR | mode, &index);
6191         if (IS_ERR(inode)) {
6192                 err = PTR_ERR(inode);
6193                 goto out_fail;
6194         }
6195
6196         drop_on_err = 1;
6197         /* these must be set before we unlock the inode */
6198         inode->i_op = &btrfs_dir_inode_operations;
6199         inode->i_fop = &btrfs_dir_file_operations;
6200
6201         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6202         if (err)
6203                 goto out_fail_inode;
6204
6205         btrfs_i_size_write(inode, 0);
6206         err = btrfs_update_inode(trans, root, inode);
6207         if (err)
6208                 goto out_fail_inode;
6209
6210         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6211                              dentry->d_name.len, 0, index);
6212         if (err)
6213                 goto out_fail_inode;
6214
6215         d_instantiate(dentry, inode);
6216         /*
6217          * mkdir is special.  We're unlocking after we call d_instantiate
6218          * to avoid a race with nfsd calling d_instantiate.
6219          */
6220         unlock_new_inode(inode);
6221         drop_on_err = 0;
6222
6223 out_fail:
6224         btrfs_end_transaction(trans, root);
6225         if (drop_on_err)
6226                 iput(inode);
6227         btrfs_balance_delayed_items(root);
6228         btrfs_btree_balance_dirty(root);
6229         return err;
6230
6231 out_fail_inode:
6232         unlock_new_inode(inode);
6233         goto out_fail;
6234 }
6235
6236 /* Find next extent map of a given extent map, caller needs to ensure locks */
6237 static struct extent_map *next_extent_map(struct extent_map *em)
6238 {
6239         struct rb_node *next;
6240
6241         next = rb_next(&em->rb_node);
6242         if (!next)
6243                 return NULL;
6244         return container_of(next, struct extent_map, rb_node);
6245 }
6246
6247 static struct extent_map *prev_extent_map(struct extent_map *em)
6248 {
6249         struct rb_node *prev;
6250
6251         prev = rb_prev(&em->rb_node);
6252         if (!prev)
6253                 return NULL;
6254         return container_of(prev, struct extent_map, rb_node);
6255 }
6256
6257 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6258  * the existing extent is the nearest extent to map_start,
6259  * and an extent that you want to insert, deal with overlap and insert
6260  * the best fitted new extent into the tree.
6261  */
6262 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6263                                 struct extent_map *existing,
6264                                 struct extent_map *em,
6265                                 u64 map_start)
6266 {
6267         struct extent_map *prev;
6268         struct extent_map *next;
6269         u64 start;
6270         u64 end;
6271         u64 start_diff;
6272
6273         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6274
6275         if (existing->start > map_start) {
6276                 next = existing;
6277                 prev = prev_extent_map(next);
6278         } else {
6279                 prev = existing;
6280                 next = next_extent_map(prev);
6281         }
6282
6283         start = prev ? extent_map_end(prev) : em->start;
6284         start = max_t(u64, start, em->start);
6285         end = next ? next->start : extent_map_end(em);
6286         end = min_t(u64, end, extent_map_end(em));
6287         start_diff = start - em->start;
6288         em->start = start;
6289         em->len = end - start;
6290         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6291             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6292                 em->block_start += start_diff;
6293                 em->block_len -= start_diff;
6294         }
6295         return add_extent_mapping(em_tree, em, 0);
6296 }
6297
6298 static noinline int uncompress_inline(struct btrfs_path *path,
6299                                       struct inode *inode, struct page *page,
6300                                       size_t pg_offset, u64 extent_offset,
6301                                       struct btrfs_file_extent_item *item)
6302 {
6303         int ret;
6304         struct extent_buffer *leaf = path->nodes[0];
6305         char *tmp;
6306         size_t max_size;
6307         unsigned long inline_size;
6308         unsigned long ptr;
6309         int compress_type;
6310
6311         WARN_ON(pg_offset != 0);
6312         compress_type = btrfs_file_extent_compression(leaf, item);
6313         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6314         inline_size = btrfs_file_extent_inline_item_len(leaf,
6315                                         btrfs_item_nr(path->slots[0]));
6316         tmp = kmalloc(inline_size, GFP_NOFS);
6317         if (!tmp)
6318                 return -ENOMEM;
6319         ptr = btrfs_file_extent_inline_start(item);
6320
6321         read_extent_buffer(leaf, tmp, ptr, inline_size);
6322
6323         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6324         ret = btrfs_decompress(compress_type, tmp, page,
6325                                extent_offset, inline_size, max_size);
6326         kfree(tmp);
6327         return ret;
6328 }
6329
6330 /*
6331  * a bit scary, this does extent mapping from logical file offset to the disk.
6332  * the ugly parts come from merging extents from the disk with the in-ram
6333  * representation.  This gets more complex because of the data=ordered code,
6334  * where the in-ram extents might be locked pending data=ordered completion.
6335  *
6336  * This also copies inline extents directly into the page.
6337  */
6338
6339 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6340                                     size_t pg_offset, u64 start, u64 len,
6341                                     int create)
6342 {
6343         int ret;
6344         int err = 0;
6345         u64 extent_start = 0;
6346         u64 extent_end = 0;
6347         u64 objectid = btrfs_ino(inode);
6348         u32 found_type;
6349         struct btrfs_path *path = NULL;
6350         struct btrfs_root *root = BTRFS_I(inode)->root;
6351         struct btrfs_file_extent_item *item;
6352         struct extent_buffer *leaf;
6353         struct btrfs_key found_key;
6354         struct extent_map *em = NULL;
6355         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6356         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6357         struct btrfs_trans_handle *trans = NULL;
6358         const bool new_inline = !page || create;
6359
6360 again:
6361         read_lock(&em_tree->lock);
6362         em = lookup_extent_mapping(em_tree, start, len);
6363         if (em)
6364                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6365         read_unlock(&em_tree->lock);
6366
6367         if (em) {
6368                 if (em->start > start || em->start + em->len <= start)
6369                         free_extent_map(em);
6370                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6371                         free_extent_map(em);
6372                 else
6373                         goto out;
6374         }
6375         em = alloc_extent_map();
6376         if (!em) {
6377                 err = -ENOMEM;
6378                 goto out;
6379         }
6380         em->bdev = root->fs_info->fs_devices->latest_bdev;
6381         em->start = EXTENT_MAP_HOLE;
6382         em->orig_start = EXTENT_MAP_HOLE;
6383         em->len = (u64)-1;
6384         em->block_len = (u64)-1;
6385
6386         if (!path) {
6387                 path = btrfs_alloc_path();
6388                 if (!path) {
6389                         err = -ENOMEM;
6390                         goto out;
6391                 }
6392                 /*
6393                  * Chances are we'll be called again, so go ahead and do
6394                  * readahead
6395                  */
6396                 path->reada = 1;
6397         }
6398
6399         ret = btrfs_lookup_file_extent(trans, root, path,
6400                                        objectid, start, trans != NULL);
6401         if (ret < 0) {
6402                 err = ret;
6403                 goto out;
6404         }
6405
6406         if (ret != 0) {
6407                 if (path->slots[0] == 0)
6408                         goto not_found;
6409                 path->slots[0]--;
6410         }
6411
6412         leaf = path->nodes[0];
6413         item = btrfs_item_ptr(leaf, path->slots[0],
6414                               struct btrfs_file_extent_item);
6415         /* are we inside the extent that was found? */
6416         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6417         found_type = found_key.type;
6418         if (found_key.objectid != objectid ||
6419             found_type != BTRFS_EXTENT_DATA_KEY) {
6420                 /*
6421                  * If we backup past the first extent we want to move forward
6422                  * and see if there is an extent in front of us, otherwise we'll
6423                  * say there is a hole for our whole search range which can
6424                  * cause problems.
6425                  */
6426                 extent_end = start;
6427                 goto next;
6428         }
6429
6430         found_type = btrfs_file_extent_type(leaf, item);
6431         extent_start = found_key.offset;
6432         if (found_type == BTRFS_FILE_EXTENT_REG ||
6433             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6434                 extent_end = extent_start +
6435                        btrfs_file_extent_num_bytes(leaf, item);
6436         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6437                 size_t size;
6438                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6439                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6440         }
6441 next:
6442         if (start >= extent_end) {
6443                 path->slots[0]++;
6444                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6445                         ret = btrfs_next_leaf(root, path);
6446                         if (ret < 0) {
6447                                 err = ret;
6448                                 goto out;
6449                         }
6450                         if (ret > 0)
6451                                 goto not_found;
6452                         leaf = path->nodes[0];
6453                 }
6454                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6455                 if (found_key.objectid != objectid ||
6456                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6457                         goto not_found;
6458                 if (start + len <= found_key.offset)
6459                         goto not_found;
6460                 if (start > found_key.offset)
6461                         goto next;
6462                 em->start = start;
6463                 em->orig_start = start;
6464                 em->len = found_key.offset - start;
6465                 goto not_found_em;
6466         }
6467
6468         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6469
6470         if (found_type == BTRFS_FILE_EXTENT_REG ||
6471             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6472                 goto insert;
6473         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6474                 unsigned long ptr;
6475                 char *map;
6476                 size_t size;
6477                 size_t extent_offset;
6478                 size_t copy_size;
6479
6480                 if (new_inline)
6481                         goto out;
6482
6483                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6484                 extent_offset = page_offset(page) + pg_offset - extent_start;
6485                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6486                                 size - extent_offset);
6487                 em->start = extent_start + extent_offset;
6488                 em->len = ALIGN(copy_size, root->sectorsize);
6489                 em->orig_block_len = em->len;
6490                 em->orig_start = em->start;
6491                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6492                 if (create == 0 && !PageUptodate(page)) {
6493                         if (btrfs_file_extent_compression(leaf, item) !=
6494                             BTRFS_COMPRESS_NONE) {
6495                                 ret = uncompress_inline(path, inode, page,
6496                                                         pg_offset,
6497                                                         extent_offset, item);
6498                                 if (ret) {
6499                                         err = ret;
6500                                         goto out;
6501                                 }
6502                         } else {
6503                                 map = kmap(page);
6504                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6505                                                    copy_size);
6506                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6507                                         memset(map + pg_offset + copy_size, 0,
6508                                                PAGE_CACHE_SIZE - pg_offset -
6509                                                copy_size);
6510                                 }
6511                                 kunmap(page);
6512                         }
6513                         flush_dcache_page(page);
6514                 } else if (create && PageUptodate(page)) {
6515                         BUG();
6516                         if (!trans) {
6517                                 kunmap(page);
6518                                 free_extent_map(em);
6519                                 em = NULL;
6520
6521                                 btrfs_release_path(path);
6522                                 trans = btrfs_join_transaction(root);
6523
6524                                 if (IS_ERR(trans))
6525                                         return ERR_CAST(trans);
6526                                 goto again;
6527                         }
6528                         map = kmap(page);
6529                         write_extent_buffer(leaf, map + pg_offset, ptr,
6530                                             copy_size);
6531                         kunmap(page);
6532                         btrfs_mark_buffer_dirty(leaf);
6533                 }
6534                 set_extent_uptodate(io_tree, em->start,
6535                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6536                 goto insert;
6537         }
6538 not_found:
6539         em->start = start;
6540         em->orig_start = start;
6541         em->len = len;
6542 not_found_em:
6543         em->block_start = EXTENT_MAP_HOLE;
6544         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6545 insert:
6546         btrfs_release_path(path);
6547         if (em->start > start || extent_map_end(em) <= start) {
6548                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6549                         em->start, em->len, start, len);
6550                 err = -EIO;
6551                 goto out;
6552         }
6553
6554         err = 0;
6555         write_lock(&em_tree->lock);
6556         ret = add_extent_mapping(em_tree, em, 0);
6557         /* it is possible that someone inserted the extent into the tree
6558          * while we had the lock dropped.  It is also possible that
6559          * an overlapping map exists in the tree
6560          */
6561         if (ret == -EEXIST) {
6562                 struct extent_map *existing;
6563
6564                 ret = 0;
6565
6566                 existing = search_extent_mapping(em_tree, start, len);
6567                 /*
6568                  * existing will always be non-NULL, since there must be
6569                  * extent causing the -EEXIST.
6570                  */
6571                 if (start >= extent_map_end(existing) ||
6572                     start <= existing->start) {
6573                         /*
6574                          * The existing extent map is the one nearest to
6575                          * the [start, start + len) range which overlaps
6576                          */
6577                         err = merge_extent_mapping(em_tree, existing,
6578                                                    em, start);
6579                         free_extent_map(existing);
6580                         if (err) {
6581                                 free_extent_map(em);
6582                                 em = NULL;
6583                         }
6584                 } else {
6585                         free_extent_map(em);
6586                         em = existing;
6587                         err = 0;
6588                 }
6589         }
6590         write_unlock(&em_tree->lock);
6591 out:
6592
6593         trace_btrfs_get_extent(root, em);
6594
6595         if (path)
6596                 btrfs_free_path(path);
6597         if (trans) {
6598                 ret = btrfs_end_transaction(trans, root);
6599                 if (!err)
6600                         err = ret;
6601         }
6602         if (err) {
6603                 free_extent_map(em);
6604                 return ERR_PTR(err);
6605         }
6606         BUG_ON(!em); /* Error is always set */
6607         return em;
6608 }
6609
6610 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6611                                            size_t pg_offset, u64 start, u64 len,
6612                                            int create)
6613 {
6614         struct extent_map *em;
6615         struct extent_map *hole_em = NULL;
6616         u64 range_start = start;
6617         u64 end;
6618         u64 found;
6619         u64 found_end;
6620         int err = 0;
6621
6622         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6623         if (IS_ERR(em))
6624                 return em;
6625         if (em) {
6626                 /*
6627                  * if our em maps to
6628                  * -  a hole or
6629                  * -  a pre-alloc extent,
6630                  * there might actually be delalloc bytes behind it.
6631                  */
6632                 if (em->block_start != EXTENT_MAP_HOLE &&
6633                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6634                         return em;
6635                 else
6636                         hole_em = em;
6637         }
6638
6639         /* check to see if we've wrapped (len == -1 or similar) */
6640         end = start + len;
6641         if (end < start)
6642                 end = (u64)-1;
6643         else
6644                 end -= 1;
6645
6646         em = NULL;
6647
6648         /* ok, we didn't find anything, lets look for delalloc */
6649         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6650                                  end, len, EXTENT_DELALLOC, 1);
6651         found_end = range_start + found;
6652         if (found_end < range_start)
6653                 found_end = (u64)-1;
6654
6655         /*
6656          * we didn't find anything useful, return
6657          * the original results from get_extent()
6658          */
6659         if (range_start > end || found_end <= start) {
6660                 em = hole_em;
6661                 hole_em = NULL;
6662                 goto out;
6663         }
6664
6665         /* adjust the range_start to make sure it doesn't
6666          * go backwards from the start they passed in
6667          */
6668         range_start = max(start, range_start);
6669         found = found_end - range_start;
6670
6671         if (found > 0) {
6672                 u64 hole_start = start;
6673                 u64 hole_len = len;
6674
6675                 em = alloc_extent_map();
6676                 if (!em) {
6677                         err = -ENOMEM;
6678                         goto out;
6679                 }
6680                 /*
6681                  * when btrfs_get_extent can't find anything it
6682                  * returns one huge hole
6683                  *
6684                  * make sure what it found really fits our range, and
6685                  * adjust to make sure it is based on the start from
6686                  * the caller
6687                  */
6688                 if (hole_em) {
6689                         u64 calc_end = extent_map_end(hole_em);
6690
6691                         if (calc_end <= start || (hole_em->start > end)) {
6692                                 free_extent_map(hole_em);
6693                                 hole_em = NULL;
6694                         } else {
6695                                 hole_start = max(hole_em->start, start);
6696                                 hole_len = calc_end - hole_start;
6697                         }
6698                 }
6699                 em->bdev = NULL;
6700                 if (hole_em && range_start > hole_start) {
6701                         /* our hole starts before our delalloc, so we
6702                          * have to return just the parts of the hole
6703                          * that go until  the delalloc starts
6704                          */
6705                         em->len = min(hole_len,
6706                                       range_start - hole_start);
6707                         em->start = hole_start;
6708                         em->orig_start = hole_start;
6709                         /*
6710                          * don't adjust block start at all,
6711                          * it is fixed at EXTENT_MAP_HOLE
6712                          */
6713                         em->block_start = hole_em->block_start;
6714                         em->block_len = hole_len;
6715                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6716                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6717                 } else {
6718                         em->start = range_start;
6719                         em->len = found;
6720                         em->orig_start = range_start;
6721                         em->block_start = EXTENT_MAP_DELALLOC;
6722                         em->block_len = found;
6723                 }
6724         } else if (hole_em) {
6725                 return hole_em;
6726         }
6727 out:
6728
6729         free_extent_map(hole_em);
6730         if (err) {
6731                 free_extent_map(em);
6732                 return ERR_PTR(err);
6733         }
6734         return em;
6735 }
6736
6737 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6738                                                   u64 start, u64 len)
6739 {
6740         struct btrfs_root *root = BTRFS_I(inode)->root;
6741         struct extent_map *em;
6742         struct btrfs_key ins;
6743         u64 alloc_hint;
6744         int ret;
6745
6746         alloc_hint = get_extent_allocation_hint(inode, start, len);
6747         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6748                                    alloc_hint, &ins, 1, 1);
6749         if (ret)
6750                 return ERR_PTR(ret);
6751
6752         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6753                               ins.offset, ins.offset, ins.offset, 0);
6754         if (IS_ERR(em)) {
6755                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6756                 return em;
6757         }
6758
6759         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6760                                            ins.offset, ins.offset, 0);
6761         if (ret) {
6762                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6763                 free_extent_map(em);
6764                 return ERR_PTR(ret);
6765         }
6766
6767         return em;
6768 }
6769
6770 /*
6771  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6772  * block must be cow'd
6773  */
6774 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6775                               u64 *orig_start, u64 *orig_block_len,
6776                               u64 *ram_bytes)
6777 {
6778         struct btrfs_trans_handle *trans;
6779         struct btrfs_path *path;
6780         int ret;
6781         struct extent_buffer *leaf;
6782         struct btrfs_root *root = BTRFS_I(inode)->root;
6783         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6784         struct btrfs_file_extent_item *fi;
6785         struct btrfs_key key;
6786         u64 disk_bytenr;
6787         u64 backref_offset;
6788         u64 extent_end;
6789         u64 num_bytes;
6790         int slot;
6791         int found_type;
6792         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6793
6794         path = btrfs_alloc_path();
6795         if (!path)
6796                 return -ENOMEM;
6797
6798         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6799                                        offset, 0);
6800         if (ret < 0)
6801                 goto out;
6802
6803         slot = path->slots[0];
6804         if (ret == 1) {
6805                 if (slot == 0) {
6806                         /* can't find the item, must cow */
6807                         ret = 0;
6808                         goto out;
6809                 }
6810                 slot--;
6811         }
6812         ret = 0;
6813         leaf = path->nodes[0];
6814         btrfs_item_key_to_cpu(leaf, &key, slot);
6815         if (key.objectid != btrfs_ino(inode) ||
6816             key.type != BTRFS_EXTENT_DATA_KEY) {
6817                 /* not our file or wrong item type, must cow */
6818                 goto out;
6819         }
6820
6821         if (key.offset > offset) {
6822                 /* Wrong offset, must cow */
6823                 goto out;
6824         }
6825
6826         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6827         found_type = btrfs_file_extent_type(leaf, fi);
6828         if (found_type != BTRFS_FILE_EXTENT_REG &&
6829             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6830                 /* not a regular extent, must cow */
6831                 goto out;
6832         }
6833
6834         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6835                 goto out;
6836
6837         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6838         if (extent_end <= offset)
6839                 goto out;
6840
6841         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6842         if (disk_bytenr == 0)
6843                 goto out;
6844
6845         if (btrfs_file_extent_compression(leaf, fi) ||
6846             btrfs_file_extent_encryption(leaf, fi) ||
6847             btrfs_file_extent_other_encoding(leaf, fi))
6848                 goto out;
6849
6850         backref_offset = btrfs_file_extent_offset(leaf, fi);
6851
6852         if (orig_start) {
6853                 *orig_start = key.offset - backref_offset;
6854                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6855                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6856         }
6857
6858         if (btrfs_extent_readonly(root, disk_bytenr))
6859                 goto out;
6860
6861         num_bytes = min(offset + *len, extent_end) - offset;
6862         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6863                 u64 range_end;
6864
6865                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6866                 ret = test_range_bit(io_tree, offset, range_end,
6867                                      EXTENT_DELALLOC, 0, NULL);
6868                 if (ret) {
6869                         ret = -EAGAIN;
6870                         goto out;
6871                 }
6872         }
6873
6874         btrfs_release_path(path);
6875
6876         /*
6877          * look for other files referencing this extent, if we
6878          * find any we must cow
6879          */
6880         trans = btrfs_join_transaction(root);
6881         if (IS_ERR(trans)) {
6882                 ret = 0;
6883                 goto out;
6884         }
6885
6886         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6887                                     key.offset - backref_offset, disk_bytenr);
6888         btrfs_end_transaction(trans, root);
6889         if (ret) {
6890                 ret = 0;
6891                 goto out;
6892         }
6893
6894         /*
6895          * adjust disk_bytenr and num_bytes to cover just the bytes
6896          * in this extent we are about to write.  If there
6897          * are any csums in that range we have to cow in order
6898          * to keep the csums correct
6899          */
6900         disk_bytenr += backref_offset;
6901         disk_bytenr += offset - key.offset;
6902         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6903                                 goto out;
6904         /*
6905          * all of the above have passed, it is safe to overwrite this extent
6906          * without cow
6907          */
6908         *len = num_bytes;
6909         ret = 1;
6910 out:
6911         btrfs_free_path(path);
6912         return ret;
6913 }
6914
6915 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
6916 {
6917         struct radix_tree_root *root = &inode->i_mapping->page_tree;
6918         int found = false;
6919         void **pagep = NULL;
6920         struct page *page = NULL;
6921         int start_idx;
6922         int end_idx;
6923
6924         start_idx = start >> PAGE_CACHE_SHIFT;
6925
6926         /*
6927          * end is the last byte in the last page.  end == start is legal
6928          */
6929         end_idx = end >> PAGE_CACHE_SHIFT;
6930
6931         rcu_read_lock();
6932
6933         /* Most of the code in this while loop is lifted from
6934          * find_get_page.  It's been modified to begin searching from a
6935          * page and return just the first page found in that range.  If the
6936          * found idx is less than or equal to the end idx then we know that
6937          * a page exists.  If no pages are found or if those pages are
6938          * outside of the range then we're fine (yay!) */
6939         while (page == NULL &&
6940                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
6941                 page = radix_tree_deref_slot(pagep);
6942                 if (unlikely(!page))
6943                         break;
6944
6945                 if (radix_tree_exception(page)) {
6946                         if (radix_tree_deref_retry(page)) {
6947                                 page = NULL;
6948                                 continue;
6949                         }
6950                         /*
6951                          * Otherwise, shmem/tmpfs must be storing a swap entry
6952                          * here as an exceptional entry: so return it without
6953                          * attempting to raise page count.
6954                          */
6955                         page = NULL;
6956                         break; /* TODO: Is this relevant for this use case? */
6957                 }
6958
6959                 if (!page_cache_get_speculative(page)) {
6960                         page = NULL;
6961                         continue;
6962                 }
6963
6964                 /*
6965                  * Has the page moved?
6966                  * This is part of the lockless pagecache protocol. See
6967                  * include/linux/pagemap.h for details.
6968                  */
6969                 if (unlikely(page != *pagep)) {
6970                         page_cache_release(page);
6971                         page = NULL;
6972                 }
6973         }
6974
6975         if (page) {
6976                 if (page->index <= end_idx)
6977                         found = true;
6978                 page_cache_release(page);
6979         }
6980
6981         rcu_read_unlock();
6982         return found;
6983 }
6984
6985 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6986                               struct extent_state **cached_state, int writing)
6987 {
6988         struct btrfs_ordered_extent *ordered;
6989         int ret = 0;
6990
6991         while (1) {
6992                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6993                                  0, cached_state);
6994                 /*
6995                  * We're concerned with the entire range that we're going to be
6996                  * doing DIO to, so we need to make sure theres no ordered
6997                  * extents in this range.
6998                  */
6999                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7000                                                      lockend - lockstart + 1);
7001
7002                 /*
7003                  * We need to make sure there are no buffered pages in this
7004                  * range either, we could have raced between the invalidate in
7005                  * generic_file_direct_write and locking the extent.  The
7006                  * invalidate needs to happen so that reads after a write do not
7007                  * get stale data.
7008                  */
7009                 if (!ordered &&
7010                     (!writing ||
7011                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7012                         break;
7013
7014                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7015                                      cached_state, GFP_NOFS);
7016
7017                 if (ordered) {
7018                         btrfs_start_ordered_extent(inode, ordered, 1);
7019                         btrfs_put_ordered_extent(ordered);
7020                 } else {
7021                         /* Screw you mmap */
7022                         ret = btrfs_fdatawrite_range(inode, lockstart, lockend);
7023                         if (ret)
7024                                 break;
7025                         ret = filemap_fdatawait_range(inode->i_mapping,
7026                                                       lockstart,
7027                                                       lockend);
7028                         if (ret)
7029                                 break;
7030
7031                         /*
7032                          * If we found a page that couldn't be invalidated just
7033                          * fall back to buffered.
7034                          */
7035                         ret = invalidate_inode_pages2_range(inode->i_mapping,
7036                                         lockstart >> PAGE_CACHE_SHIFT,
7037                                         lockend >> PAGE_CACHE_SHIFT);
7038                         if (ret)
7039                                 break;
7040                 }
7041
7042                 cond_resched();
7043         }
7044
7045         return ret;
7046 }
7047
7048 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7049                                            u64 len, u64 orig_start,
7050                                            u64 block_start, u64 block_len,
7051                                            u64 orig_block_len, u64 ram_bytes,
7052                                            int type)
7053 {
7054         struct extent_map_tree *em_tree;
7055         struct extent_map *em;
7056         struct btrfs_root *root = BTRFS_I(inode)->root;
7057         int ret;
7058
7059         em_tree = &BTRFS_I(inode)->extent_tree;
7060         em = alloc_extent_map();
7061         if (!em)
7062                 return ERR_PTR(-ENOMEM);
7063
7064         em->start = start;
7065         em->orig_start = orig_start;
7066         em->mod_start = start;
7067         em->mod_len = len;
7068         em->len = len;
7069         em->block_len = block_len;
7070         em->block_start = block_start;
7071         em->bdev = root->fs_info->fs_devices->latest_bdev;
7072         em->orig_block_len = orig_block_len;
7073         em->ram_bytes = ram_bytes;
7074         em->generation = -1;
7075         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7076         if (type == BTRFS_ORDERED_PREALLOC)
7077                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7078
7079         do {
7080                 btrfs_drop_extent_cache(inode, em->start,
7081                                 em->start + em->len - 1, 0);
7082                 write_lock(&em_tree->lock);
7083                 ret = add_extent_mapping(em_tree, em, 1);
7084                 write_unlock(&em_tree->lock);
7085         } while (ret == -EEXIST);
7086
7087         if (ret) {
7088                 free_extent_map(em);
7089                 return ERR_PTR(ret);
7090         }
7091
7092         return em;
7093 }
7094
7095
7096 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7097                                    struct buffer_head *bh_result, int create)
7098 {
7099         struct extent_map *em;
7100         struct btrfs_root *root = BTRFS_I(inode)->root;
7101         struct extent_state *cached_state = NULL;
7102         u64 start = iblock << inode->i_blkbits;
7103         u64 lockstart, lockend;
7104         u64 len = bh_result->b_size;
7105         int unlock_bits = EXTENT_LOCKED;
7106         int ret = 0;
7107
7108         if (create)
7109                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
7110         else
7111                 len = min_t(u64, len, root->sectorsize);
7112
7113         lockstart = start;
7114         lockend = start + len - 1;
7115
7116         /*
7117          * If this errors out it's because we couldn't invalidate pagecache for
7118          * this range and we need to fallback to buffered.
7119          */
7120         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
7121                 return -ENOTBLK;
7122
7123         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7124         if (IS_ERR(em)) {
7125                 ret = PTR_ERR(em);
7126                 goto unlock_err;
7127         }
7128
7129         /*
7130          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7131          * io.  INLINE is special, and we could probably kludge it in here, but
7132          * it's still buffered so for safety lets just fall back to the generic
7133          * buffered path.
7134          *
7135          * For COMPRESSED we _have_ to read the entire extent in so we can
7136          * decompress it, so there will be buffering required no matter what we
7137          * do, so go ahead and fallback to buffered.
7138          *
7139          * We return -ENOTBLK because thats what makes DIO go ahead and go back
7140          * to buffered IO.  Don't blame me, this is the price we pay for using
7141          * the generic code.
7142          */
7143         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7144             em->block_start == EXTENT_MAP_INLINE) {
7145                 free_extent_map(em);
7146                 ret = -ENOTBLK;
7147                 goto unlock_err;
7148         }
7149
7150         /* Just a good old fashioned hole, return */
7151         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7152                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7153                 free_extent_map(em);
7154                 goto unlock_err;
7155         }
7156
7157         /*
7158          * We don't allocate a new extent in the following cases
7159          *
7160          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7161          * existing extent.
7162          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7163          * just use the extent.
7164          *
7165          */
7166         if (!create) {
7167                 len = min(len, em->len - (start - em->start));
7168                 lockstart = start + len;
7169                 goto unlock;
7170         }
7171
7172         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7173             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7174              em->block_start != EXTENT_MAP_HOLE)) {
7175                 int type;
7176                 int ret;
7177                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7178
7179                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7180                         type = BTRFS_ORDERED_PREALLOC;
7181                 else
7182                         type = BTRFS_ORDERED_NOCOW;
7183                 len = min(len, em->len - (start - em->start));
7184                 block_start = em->block_start + (start - em->start);
7185
7186                 if (can_nocow_extent(inode, start, &len, &orig_start,
7187                                      &orig_block_len, &ram_bytes) == 1) {
7188                         if (type == BTRFS_ORDERED_PREALLOC) {
7189                                 free_extent_map(em);
7190                                 em = create_pinned_em(inode, start, len,
7191                                                        orig_start,
7192                                                        block_start, len,
7193                                                        orig_block_len,
7194                                                        ram_bytes, type);
7195                                 if (IS_ERR(em)) {
7196                                         ret = PTR_ERR(em);
7197                                         goto unlock_err;
7198                                 }
7199                         }
7200
7201                         ret = btrfs_add_ordered_extent_dio(inode, start,
7202                                            block_start, len, len, type);
7203                         if (ret) {
7204                                 free_extent_map(em);
7205                                 goto unlock_err;
7206                         }
7207                         goto unlock;
7208                 }
7209         }
7210
7211         /*
7212          * this will cow the extent, reset the len in case we changed
7213          * it above
7214          */
7215         len = bh_result->b_size;
7216         free_extent_map(em);
7217         em = btrfs_new_extent_direct(inode, start, len);
7218         if (IS_ERR(em)) {
7219                 ret = PTR_ERR(em);
7220                 goto unlock_err;
7221         }
7222         len = min(len, em->len - (start - em->start));
7223 unlock:
7224         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7225                 inode->i_blkbits;
7226         bh_result->b_size = len;
7227         bh_result->b_bdev = em->bdev;
7228         set_buffer_mapped(bh_result);
7229         if (create) {
7230                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7231                         set_buffer_new(bh_result);
7232
7233                 /*
7234                  * Need to update the i_size under the extent lock so buffered
7235                  * readers will get the updated i_size when we unlock.
7236                  */
7237                 if (start + len > i_size_read(inode))
7238                         i_size_write(inode, start + len);
7239
7240                 spin_lock(&BTRFS_I(inode)->lock);
7241                 BTRFS_I(inode)->outstanding_extents++;
7242                 spin_unlock(&BTRFS_I(inode)->lock);
7243
7244                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7245                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
7246                                      &cached_state, GFP_NOFS);
7247                 BUG_ON(ret);
7248         }
7249
7250         /*
7251          * In the case of write we need to clear and unlock the entire range,
7252          * in the case of read we need to unlock only the end area that we
7253          * aren't using if there is any left over space.
7254          */
7255         if (lockstart < lockend) {
7256                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7257                                  lockend, unlock_bits, 1, 0,
7258                                  &cached_state, GFP_NOFS);
7259         } else {
7260                 free_extent_state(cached_state);
7261         }
7262
7263         free_extent_map(em);
7264
7265         return 0;
7266
7267 unlock_err:
7268         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7269                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7270         return ret;
7271 }
7272
7273 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7274                                         int rw, int mirror_num)
7275 {
7276         struct btrfs_root *root = BTRFS_I(inode)->root;
7277         int ret;
7278
7279         BUG_ON(rw & REQ_WRITE);
7280
7281         bio_get(bio);
7282
7283         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7284                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7285         if (ret)
7286                 goto err;
7287
7288         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
7289 err:
7290         bio_put(bio);
7291         return ret;
7292 }
7293
7294 static int btrfs_check_dio_repairable(struct inode *inode,
7295                                       struct bio *failed_bio,
7296                                       struct io_failure_record *failrec,
7297                                       int failed_mirror)
7298 {
7299         int num_copies;
7300
7301         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7302                                       failrec->logical, failrec->len);
7303         if (num_copies == 1) {
7304                 /*
7305                  * we only have a single copy of the data, so don't bother with
7306                  * all the retry and error correction code that follows. no
7307                  * matter what the error is, it is very likely to persist.
7308                  */
7309                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7310                          num_copies, failrec->this_mirror, failed_mirror);
7311                 return 0;
7312         }
7313
7314         failrec->failed_mirror = failed_mirror;
7315         failrec->this_mirror++;
7316         if (failrec->this_mirror == failed_mirror)
7317                 failrec->this_mirror++;
7318
7319         if (failrec->this_mirror > num_copies) {
7320                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7321                          num_copies, failrec->this_mirror, failed_mirror);
7322                 return 0;
7323         }
7324
7325         return 1;
7326 }
7327
7328 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7329                           struct page *page, u64 start, u64 end,
7330                           int failed_mirror, bio_end_io_t *repair_endio,
7331                           void *repair_arg)
7332 {
7333         struct io_failure_record *failrec;
7334         struct bio *bio;
7335         int isector;
7336         int read_mode;
7337         int ret;
7338
7339         BUG_ON(failed_bio->bi_rw & REQ_WRITE);
7340
7341         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7342         if (ret)
7343                 return ret;
7344
7345         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7346                                          failed_mirror);
7347         if (!ret) {
7348                 free_io_failure(inode, failrec);
7349                 return -EIO;
7350         }
7351
7352         if (failed_bio->bi_vcnt > 1)
7353                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7354         else
7355                 read_mode = READ_SYNC;
7356
7357         isector = start - btrfs_io_bio(failed_bio)->logical;
7358         isector >>= inode->i_sb->s_blocksize_bits;
7359         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7360                                       0, isector, repair_endio, repair_arg);
7361         if (!bio) {
7362                 free_io_failure(inode, failrec);
7363                 return -EIO;
7364         }
7365
7366         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7367                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7368                     read_mode, failrec->this_mirror, failrec->in_validation);
7369
7370         ret = submit_dio_repair_bio(inode, bio, read_mode,
7371                                     failrec->this_mirror);
7372         if (ret) {
7373                 free_io_failure(inode, failrec);
7374                 bio_put(bio);
7375         }
7376
7377         return ret;
7378 }
7379
7380 struct btrfs_retry_complete {
7381         struct completion done;
7382         struct inode *inode;
7383         u64 start;
7384         int uptodate;
7385 };
7386
7387 static void btrfs_retry_endio_nocsum(struct bio *bio, int err)
7388 {
7389         struct btrfs_retry_complete *done = bio->bi_private;
7390         struct bio_vec *bvec;
7391         int i;
7392
7393         if (err)
7394                 goto end;
7395
7396         done->uptodate = 1;
7397         bio_for_each_segment_all(bvec, bio, i)
7398                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7399 end:
7400         complete(&done->done);
7401         bio_put(bio);
7402 }
7403
7404 static int __btrfs_correct_data_nocsum(struct inode *inode,
7405                                        struct btrfs_io_bio *io_bio)
7406 {
7407         struct bio_vec *bvec;
7408         struct btrfs_retry_complete done;
7409         u64 start;
7410         int i;
7411         int ret;
7412
7413         start = io_bio->logical;
7414         done.inode = inode;
7415
7416         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7417 try_again:
7418                 done.uptodate = 0;
7419                 done.start = start;
7420                 init_completion(&done.done);
7421
7422                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7423                                      start + bvec->bv_len - 1,
7424                                      io_bio->mirror_num,
7425                                      btrfs_retry_endio_nocsum, &done);
7426                 if (ret)
7427                         return ret;
7428
7429                 wait_for_completion(&done.done);
7430
7431                 if (!done.uptodate) {
7432                         /* We might have another mirror, so try again */
7433                         goto try_again;
7434                 }
7435
7436                 start += bvec->bv_len;
7437         }
7438
7439         return 0;
7440 }
7441
7442 static void btrfs_retry_endio(struct bio *bio, int err)
7443 {
7444         struct btrfs_retry_complete *done = bio->bi_private;
7445         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7446         struct bio_vec *bvec;
7447         int uptodate;
7448         int ret;
7449         int i;
7450
7451         if (err)
7452                 goto end;
7453
7454         uptodate = 1;
7455         bio_for_each_segment_all(bvec, bio, i) {
7456                 ret = __readpage_endio_check(done->inode, io_bio, i,
7457                                              bvec->bv_page, 0,
7458                                              done->start, bvec->bv_len);
7459                 if (!ret)
7460                         clean_io_failure(done->inode, done->start,
7461                                          bvec->bv_page, 0);
7462                 else
7463                         uptodate = 0;
7464         }
7465
7466         done->uptodate = uptodate;
7467 end:
7468         complete(&done->done);
7469         bio_put(bio);
7470 }
7471
7472 static int __btrfs_subio_endio_read(struct inode *inode,
7473                                     struct btrfs_io_bio *io_bio, int err)
7474 {
7475         struct bio_vec *bvec;
7476         struct btrfs_retry_complete done;
7477         u64 start;
7478         u64 offset = 0;
7479         int i;
7480         int ret;
7481
7482         err = 0;
7483         start = io_bio->logical;
7484         done.inode = inode;
7485
7486         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7487                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7488                                              0, start, bvec->bv_len);
7489                 if (likely(!ret))
7490                         goto next;
7491 try_again:
7492                 done.uptodate = 0;
7493                 done.start = start;
7494                 init_completion(&done.done);
7495
7496                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7497                                      start + bvec->bv_len - 1,
7498                                      io_bio->mirror_num,
7499                                      btrfs_retry_endio, &done);
7500                 if (ret) {
7501                         err = ret;
7502                         goto next;
7503                 }
7504
7505                 wait_for_completion(&done.done);
7506
7507                 if (!done.uptodate) {
7508                         /* We might have another mirror, so try again */
7509                         goto try_again;
7510                 }
7511 next:
7512                 offset += bvec->bv_len;
7513                 start += bvec->bv_len;
7514         }
7515
7516         return err;
7517 }
7518
7519 static int btrfs_subio_endio_read(struct inode *inode,
7520                                   struct btrfs_io_bio *io_bio, int err)
7521 {
7522         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7523
7524         if (skip_csum) {
7525                 if (unlikely(err))
7526                         return __btrfs_correct_data_nocsum(inode, io_bio);
7527                 else
7528                         return 0;
7529         } else {
7530                 return __btrfs_subio_endio_read(inode, io_bio, err);
7531         }
7532 }
7533
7534 static void btrfs_endio_direct_read(struct bio *bio, int err)
7535 {
7536         struct btrfs_dio_private *dip = bio->bi_private;
7537         struct inode *inode = dip->inode;
7538         struct bio *dio_bio;
7539         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7540
7541         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
7542                 err = btrfs_subio_endio_read(inode, io_bio, err);
7543
7544         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7545                       dip->logical_offset + dip->bytes - 1);
7546         dio_bio = dip->dio_bio;
7547
7548         kfree(dip);
7549
7550         /* If we had a csum failure make sure to clear the uptodate flag */
7551         if (err)
7552                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7553         dio_end_io(dio_bio, err);
7554
7555         if (io_bio->end_io)
7556                 io_bio->end_io(io_bio, err);
7557         bio_put(bio);
7558 }
7559
7560 static void btrfs_endio_direct_write(struct bio *bio, int err)
7561 {
7562         struct btrfs_dio_private *dip = bio->bi_private;
7563         struct inode *inode = dip->inode;
7564         struct btrfs_root *root = BTRFS_I(inode)->root;
7565         struct btrfs_ordered_extent *ordered = NULL;
7566         u64 ordered_offset = dip->logical_offset;
7567         u64 ordered_bytes = dip->bytes;
7568         struct bio *dio_bio;
7569         int ret;
7570
7571         if (err)
7572                 goto out_done;
7573 again:
7574         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7575                                                    &ordered_offset,
7576                                                    ordered_bytes, !err);
7577         if (!ret)
7578                 goto out_test;
7579
7580         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
7581                         finish_ordered_fn, NULL, NULL);
7582         btrfs_queue_work(root->fs_info->endio_write_workers,
7583                          &ordered->work);
7584 out_test:
7585         /*
7586          * our bio might span multiple ordered extents.  If we haven't
7587          * completed the accounting for the whole dio, go back and try again
7588          */
7589         if (ordered_offset < dip->logical_offset + dip->bytes) {
7590                 ordered_bytes = dip->logical_offset + dip->bytes -
7591                         ordered_offset;
7592                 ordered = NULL;
7593                 goto again;
7594         }
7595 out_done:
7596         dio_bio = dip->dio_bio;
7597
7598         kfree(dip);
7599
7600         /* If we had an error make sure to clear the uptodate flag */
7601         if (err)
7602                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7603         dio_end_io(dio_bio, err);
7604         bio_put(bio);
7605 }
7606
7607 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7608                                     struct bio *bio, int mirror_num,
7609                                     unsigned long bio_flags, u64 offset)
7610 {
7611         int ret;
7612         struct btrfs_root *root = BTRFS_I(inode)->root;
7613         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7614         BUG_ON(ret); /* -ENOMEM */
7615         return 0;
7616 }
7617
7618 static void btrfs_end_dio_bio(struct bio *bio, int err)
7619 {
7620         struct btrfs_dio_private *dip = bio->bi_private;
7621
7622         if (err)
7623                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
7624                            "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7625                            btrfs_ino(dip->inode), bio->bi_rw,
7626                            (unsigned long long)bio->bi_iter.bi_sector,
7627                            bio->bi_iter.bi_size, err);
7628
7629         if (dip->subio_endio)
7630                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
7631
7632         if (err) {
7633                 dip->errors = 1;
7634
7635                 /*
7636                  * before atomic variable goto zero, we must make sure
7637                  * dip->errors is perceived to be set.
7638                  */
7639                 smp_mb__before_atomic();
7640         }
7641
7642         /* if there are more bios still pending for this dio, just exit */
7643         if (!atomic_dec_and_test(&dip->pending_bios))
7644                 goto out;
7645
7646         if (dip->errors) {
7647                 bio_io_error(dip->orig_bio);
7648         } else {
7649                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7650                 bio_endio(dip->orig_bio, 0);
7651         }
7652 out:
7653         bio_put(bio);
7654 }
7655
7656 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7657                                        u64 first_sector, gfp_t gfp_flags)
7658 {
7659         int nr_vecs = bio_get_nr_vecs(bdev);
7660         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7661 }
7662
7663 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
7664                                                  struct inode *inode,
7665                                                  struct btrfs_dio_private *dip,
7666                                                  struct bio *bio,
7667                                                  u64 file_offset)
7668 {
7669         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7670         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
7671         int ret;
7672
7673         /*
7674          * We load all the csum data we need when we submit
7675          * the first bio to reduce the csum tree search and
7676          * contention.
7677          */
7678         if (dip->logical_offset == file_offset) {
7679                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
7680                                                 file_offset);
7681                 if (ret)
7682                         return ret;
7683         }
7684
7685         if (bio == dip->orig_bio)
7686                 return 0;
7687
7688         file_offset -= dip->logical_offset;
7689         file_offset >>= inode->i_sb->s_blocksize_bits;
7690         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
7691
7692         return 0;
7693 }
7694
7695 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7696                                          int rw, u64 file_offset, int skip_sum,
7697                                          int async_submit)
7698 {
7699         struct btrfs_dio_private *dip = bio->bi_private;
7700         int write = rw & REQ_WRITE;
7701         struct btrfs_root *root = BTRFS_I(inode)->root;
7702         int ret;
7703
7704         if (async_submit)
7705                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7706
7707         bio_get(bio);
7708
7709         if (!write) {
7710                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7711                                 BTRFS_WQ_ENDIO_DATA);
7712                 if (ret)
7713                         goto err;
7714         }
7715
7716         if (skip_sum)
7717                 goto map;
7718
7719         if (write && async_submit) {
7720                 ret = btrfs_wq_submit_bio(root->fs_info,
7721                                    inode, rw, bio, 0, 0,
7722                                    file_offset,
7723                                    __btrfs_submit_bio_start_direct_io,
7724                                    __btrfs_submit_bio_done);
7725                 goto err;
7726         } else if (write) {
7727                 /*
7728                  * If we aren't doing async submit, calculate the csum of the
7729                  * bio now.
7730                  */
7731                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7732                 if (ret)
7733                         goto err;
7734         } else {
7735                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
7736                                                      file_offset);
7737                 if (ret)
7738                         goto err;
7739         }
7740 map:
7741         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7742 err:
7743         bio_put(bio);
7744         return ret;
7745 }
7746
7747 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7748                                     int skip_sum)
7749 {
7750         struct inode *inode = dip->inode;
7751         struct btrfs_root *root = BTRFS_I(inode)->root;
7752         struct bio *bio;
7753         struct bio *orig_bio = dip->orig_bio;
7754         struct bio_vec *bvec = orig_bio->bi_io_vec;
7755         u64 start_sector = orig_bio->bi_iter.bi_sector;
7756         u64 file_offset = dip->logical_offset;
7757         u64 submit_len = 0;
7758         u64 map_length;
7759         int nr_pages = 0;
7760         int ret;
7761         int async_submit = 0;
7762
7763         map_length = orig_bio->bi_iter.bi_size;
7764         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7765                               &map_length, NULL, 0);
7766         if (ret)
7767                 return -EIO;
7768
7769         if (map_length >= orig_bio->bi_iter.bi_size) {
7770                 bio = orig_bio;
7771                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
7772                 goto submit;
7773         }
7774
7775         /* async crcs make it difficult to collect full stripe writes. */
7776         if (btrfs_get_alloc_profile(root, 1) &
7777             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7778                 async_submit = 0;
7779         else
7780                 async_submit = 1;
7781
7782         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7783         if (!bio)
7784                 return -ENOMEM;
7785
7786         bio->bi_private = dip;
7787         bio->bi_end_io = btrfs_end_dio_bio;
7788         btrfs_io_bio(bio)->logical = file_offset;
7789         atomic_inc(&dip->pending_bios);
7790
7791         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7792                 if (map_length < submit_len + bvec->bv_len ||
7793                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7794                                  bvec->bv_offset) < bvec->bv_len) {
7795                         /*
7796                          * inc the count before we submit the bio so
7797                          * we know the end IO handler won't happen before
7798                          * we inc the count. Otherwise, the dip might get freed
7799                          * before we're done setting it up
7800                          */
7801                         atomic_inc(&dip->pending_bios);
7802                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7803                                                      file_offset, skip_sum,
7804                                                      async_submit);
7805                         if (ret) {
7806                                 bio_put(bio);
7807                                 atomic_dec(&dip->pending_bios);
7808                                 goto out_err;
7809                         }
7810
7811                         start_sector += submit_len >> 9;
7812                         file_offset += submit_len;
7813
7814                         submit_len = 0;
7815                         nr_pages = 0;
7816
7817                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7818                                                   start_sector, GFP_NOFS);
7819                         if (!bio)
7820                                 goto out_err;
7821                         bio->bi_private = dip;
7822                         bio->bi_end_io = btrfs_end_dio_bio;
7823                         btrfs_io_bio(bio)->logical = file_offset;
7824
7825                         map_length = orig_bio->bi_iter.bi_size;
7826                         ret = btrfs_map_block(root->fs_info, rw,
7827                                               start_sector << 9,
7828                                               &map_length, NULL, 0);
7829                         if (ret) {
7830                                 bio_put(bio);
7831                                 goto out_err;
7832                         }
7833                 } else {
7834                         submit_len += bvec->bv_len;
7835                         nr_pages++;
7836                         bvec++;
7837                 }
7838         }
7839
7840 submit:
7841         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7842                                      async_submit);
7843         if (!ret)
7844                 return 0;
7845
7846         bio_put(bio);
7847 out_err:
7848         dip->errors = 1;
7849         /*
7850          * before atomic variable goto zero, we must
7851          * make sure dip->errors is perceived to be set.
7852          */
7853         smp_mb__before_atomic();
7854         if (atomic_dec_and_test(&dip->pending_bios))
7855                 bio_io_error(dip->orig_bio);
7856
7857         /* bio_end_io() will handle error, so we needn't return it */
7858         return 0;
7859 }
7860
7861 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7862                                 struct inode *inode, loff_t file_offset)
7863 {
7864         struct btrfs_root *root = BTRFS_I(inode)->root;
7865         struct btrfs_dio_private *dip;
7866         struct bio *io_bio;
7867         struct btrfs_io_bio *btrfs_bio;
7868         int skip_sum;
7869         int write = rw & REQ_WRITE;
7870         int ret = 0;
7871
7872         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7873
7874         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7875         if (!io_bio) {
7876                 ret = -ENOMEM;
7877                 goto free_ordered;
7878         }
7879
7880         dip = kzalloc(sizeof(*dip), GFP_NOFS);
7881         if (!dip) {
7882                 ret = -ENOMEM;
7883                 goto free_io_bio;
7884         }
7885
7886         dip->private = dio_bio->bi_private;
7887         dip->inode = inode;
7888         dip->logical_offset = file_offset;
7889         dip->bytes = dio_bio->bi_iter.bi_size;
7890         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7891         io_bio->bi_private = dip;
7892         dip->orig_bio = io_bio;
7893         dip->dio_bio = dio_bio;
7894         atomic_set(&dip->pending_bios, 0);
7895         btrfs_bio = btrfs_io_bio(io_bio);
7896         btrfs_bio->logical = file_offset;
7897
7898         if (write) {
7899                 io_bio->bi_end_io = btrfs_endio_direct_write;
7900         } else {
7901                 io_bio->bi_end_io = btrfs_endio_direct_read;
7902                 dip->subio_endio = btrfs_subio_endio_read;
7903         }
7904
7905         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7906         if (!ret)
7907                 return;
7908
7909         if (btrfs_bio->end_io)
7910                 btrfs_bio->end_io(btrfs_bio, ret);
7911 free_io_bio:
7912         bio_put(io_bio);
7913
7914 free_ordered:
7915         /*
7916          * If this is a write, we need to clean up the reserved space and kill
7917          * the ordered extent.
7918          */
7919         if (write) {
7920                 struct btrfs_ordered_extent *ordered;
7921                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7922                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7923                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7924                         btrfs_free_reserved_extent(root, ordered->start,
7925                                                    ordered->disk_len, 1);
7926                 btrfs_put_ordered_extent(ordered);
7927                 btrfs_put_ordered_extent(ordered);
7928         }
7929         bio_endio(dio_bio, ret);
7930 }
7931
7932 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7933                         const struct iov_iter *iter, loff_t offset)
7934 {
7935         int seg;
7936         int i;
7937         unsigned blocksize_mask = root->sectorsize - 1;
7938         ssize_t retval = -EINVAL;
7939
7940         if (offset & blocksize_mask)
7941                 goto out;
7942
7943         if (iov_iter_alignment(iter) & blocksize_mask)
7944                 goto out;
7945
7946         /* If this is a write we don't need to check anymore */
7947         if (rw & WRITE)
7948                 return 0;
7949         /*
7950          * Check to make sure we don't have duplicate iov_base's in this
7951          * iovec, if so return EINVAL, otherwise we'll get csum errors
7952          * when reading back.
7953          */
7954         for (seg = 0; seg < iter->nr_segs; seg++) {
7955                 for (i = seg + 1; i < iter->nr_segs; i++) {
7956                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
7957                                 goto out;
7958                 }
7959         }
7960         retval = 0;
7961 out:
7962         return retval;
7963 }
7964
7965 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7966                         struct iov_iter *iter, loff_t offset)
7967 {
7968         struct file *file = iocb->ki_filp;
7969         struct inode *inode = file->f_mapping->host;
7970         size_t count = 0;
7971         int flags = 0;
7972         bool wakeup = true;
7973         bool relock = false;
7974         ssize_t ret;
7975
7976         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter, offset))
7977                 return 0;
7978
7979         atomic_inc(&inode->i_dio_count);
7980         smp_mb__after_atomic();
7981
7982         /*
7983          * The generic stuff only does filemap_write_and_wait_range, which
7984          * isn't enough if we've written compressed pages to this area, so
7985          * we need to flush the dirty pages again to make absolutely sure
7986          * that any outstanding dirty pages are on disk.
7987          */
7988         count = iov_iter_count(iter);
7989         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
7990                      &BTRFS_I(inode)->runtime_flags))
7991                 filemap_fdatawrite_range(inode->i_mapping, offset,
7992                                          offset + count - 1);
7993
7994         if (rw & WRITE) {
7995                 /*
7996                  * If the write DIO is beyond the EOF, we need update
7997                  * the isize, but it is protected by i_mutex. So we can
7998                  * not unlock the i_mutex at this case.
7999                  */
8000                 if (offset + count <= inode->i_size) {
8001                         mutex_unlock(&inode->i_mutex);
8002                         relock = true;
8003                 }
8004                 ret = btrfs_delalloc_reserve_space(inode, count);
8005                 if (ret)
8006                         goto out;
8007         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8008                                      &BTRFS_I(inode)->runtime_flags)) {
8009                 inode_dio_done(inode);
8010                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8011                 wakeup = false;
8012         }
8013
8014         ret = __blockdev_direct_IO(rw, iocb, inode,
8015                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8016                         iter, offset, btrfs_get_blocks_direct, NULL,
8017                         btrfs_submit_direct, flags);
8018         if (rw & WRITE) {
8019                 if (ret < 0 && ret != -EIOCBQUEUED)
8020                         btrfs_delalloc_release_space(inode, count);
8021                 else if (ret >= 0 && (size_t)ret < count)
8022                         btrfs_delalloc_release_space(inode,
8023                                                      count - (size_t)ret);
8024                 else
8025                         btrfs_delalloc_release_metadata(inode, 0);
8026         }
8027 out:
8028         if (wakeup)
8029                 inode_dio_done(inode);
8030         if (relock)
8031                 mutex_lock(&inode->i_mutex);
8032
8033         return ret;
8034 }
8035
8036 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8037
8038 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8039                 __u64 start, __u64 len)
8040 {
8041         int     ret;
8042
8043         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8044         if (ret)
8045                 return ret;
8046
8047         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8048 }
8049
8050 int btrfs_readpage(struct file *file, struct page *page)
8051 {
8052         struct extent_io_tree *tree;
8053         tree = &BTRFS_I(page->mapping->host)->io_tree;
8054         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8055 }
8056
8057 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8058 {
8059         struct extent_io_tree *tree;
8060
8061
8062         if (current->flags & PF_MEMALLOC) {
8063                 redirty_page_for_writepage(wbc, page);
8064                 unlock_page(page);
8065                 return 0;
8066         }
8067         tree = &BTRFS_I(page->mapping->host)->io_tree;
8068         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8069 }
8070
8071 static int btrfs_writepages(struct address_space *mapping,
8072                             struct writeback_control *wbc)
8073 {
8074         struct extent_io_tree *tree;
8075
8076         tree = &BTRFS_I(mapping->host)->io_tree;
8077         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8078 }
8079
8080 static int
8081 btrfs_readpages(struct file *file, struct address_space *mapping,
8082                 struct list_head *pages, unsigned nr_pages)
8083 {
8084         struct extent_io_tree *tree;
8085         tree = &BTRFS_I(mapping->host)->io_tree;
8086         return extent_readpages(tree, mapping, pages, nr_pages,
8087                                 btrfs_get_extent);
8088 }
8089 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8090 {
8091         struct extent_io_tree *tree;
8092         struct extent_map_tree *map;
8093         int ret;
8094
8095         tree = &BTRFS_I(page->mapping->host)->io_tree;
8096         map = &BTRFS_I(page->mapping->host)->extent_tree;
8097         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8098         if (ret == 1) {
8099                 ClearPagePrivate(page);
8100                 set_page_private(page, 0);
8101                 page_cache_release(page);
8102         }
8103         return ret;
8104 }
8105
8106 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8107 {
8108         if (PageWriteback(page) || PageDirty(page))
8109                 return 0;
8110         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8111 }
8112
8113 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8114                                  unsigned int length)
8115 {
8116         struct inode *inode = page->mapping->host;
8117         struct extent_io_tree *tree;
8118         struct btrfs_ordered_extent *ordered;
8119         struct extent_state *cached_state = NULL;
8120         u64 page_start = page_offset(page);
8121         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
8122         int inode_evicting = inode->i_state & I_FREEING;
8123
8124         /*
8125          * we have the page locked, so new writeback can't start,
8126          * and the dirty bit won't be cleared while we are here.
8127          *
8128          * Wait for IO on this page so that we can safely clear
8129          * the PagePrivate2 bit and do ordered accounting
8130          */
8131         wait_on_page_writeback(page);
8132
8133         tree = &BTRFS_I(inode)->io_tree;
8134         if (offset) {
8135                 btrfs_releasepage(page, GFP_NOFS);
8136                 return;
8137         }
8138
8139         if (!inode_evicting)
8140                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
8141         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8142         if (ordered) {
8143                 /*
8144                  * IO on this page will never be started, so we need
8145                  * to account for any ordered extents now
8146                  */
8147                 if (!inode_evicting)
8148                         clear_extent_bit(tree, page_start, page_end,
8149                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8150                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8151                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8152                                          GFP_NOFS);
8153                 /*
8154                  * whoever cleared the private bit is responsible
8155                  * for the finish_ordered_io
8156                  */
8157                 if (TestClearPagePrivate2(page)) {
8158                         struct btrfs_ordered_inode_tree *tree;
8159                         u64 new_len;
8160
8161                         tree = &BTRFS_I(inode)->ordered_tree;
8162
8163                         spin_lock_irq(&tree->lock);
8164                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8165                         new_len = page_start - ordered->file_offset;
8166                         if (new_len < ordered->truncated_len)
8167                                 ordered->truncated_len = new_len;
8168                         spin_unlock_irq(&tree->lock);
8169
8170                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8171                                                            page_start,
8172                                                            PAGE_CACHE_SIZE, 1))
8173                                 btrfs_finish_ordered_io(ordered);
8174                 }
8175                 btrfs_put_ordered_extent(ordered);
8176                 if (!inode_evicting) {
8177                         cached_state = NULL;
8178                         lock_extent_bits(tree, page_start, page_end, 0,
8179                                          &cached_state);
8180                 }
8181         }
8182
8183         if (!inode_evicting) {
8184                 clear_extent_bit(tree, page_start, page_end,
8185                                  EXTENT_LOCKED | EXTENT_DIRTY |
8186                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8187                                  EXTENT_DEFRAG, 1, 1,
8188                                  &cached_state, GFP_NOFS);
8189
8190                 __btrfs_releasepage(page, GFP_NOFS);
8191         }
8192
8193         ClearPageChecked(page);
8194         if (PagePrivate(page)) {
8195                 ClearPagePrivate(page);
8196                 set_page_private(page, 0);
8197                 page_cache_release(page);
8198         }
8199 }
8200
8201 /*
8202  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8203  * called from a page fault handler when a page is first dirtied. Hence we must
8204  * be careful to check for EOF conditions here. We set the page up correctly
8205  * for a written page which means we get ENOSPC checking when writing into
8206  * holes and correct delalloc and unwritten extent mapping on filesystems that
8207  * support these features.
8208  *
8209  * We are not allowed to take the i_mutex here so we have to play games to
8210  * protect against truncate races as the page could now be beyond EOF.  Because
8211  * vmtruncate() writes the inode size before removing pages, once we have the
8212  * page lock we can determine safely if the page is beyond EOF. If it is not
8213  * beyond EOF, then the page is guaranteed safe against truncation until we
8214  * unlock the page.
8215  */
8216 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8217 {
8218         struct page *page = vmf->page;
8219         struct inode *inode = file_inode(vma->vm_file);
8220         struct btrfs_root *root = BTRFS_I(inode)->root;
8221         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8222         struct btrfs_ordered_extent *ordered;
8223         struct extent_state *cached_state = NULL;
8224         char *kaddr;
8225         unsigned long zero_start;
8226         loff_t size;
8227         int ret;
8228         int reserved = 0;
8229         u64 page_start;
8230         u64 page_end;
8231
8232         sb_start_pagefault(inode->i_sb);
8233         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
8234         if (!ret) {
8235                 ret = file_update_time(vma->vm_file);
8236                 reserved = 1;
8237         }
8238         if (ret) {
8239                 if (ret == -ENOMEM)
8240                         ret = VM_FAULT_OOM;
8241                 else /* -ENOSPC, -EIO, etc */
8242                         ret = VM_FAULT_SIGBUS;
8243                 if (reserved)
8244                         goto out;
8245                 goto out_noreserve;
8246         }
8247
8248         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8249 again:
8250         lock_page(page);
8251         size = i_size_read(inode);
8252         page_start = page_offset(page);
8253         page_end = page_start + PAGE_CACHE_SIZE - 1;
8254
8255         if ((page->mapping != inode->i_mapping) ||
8256             (page_start >= size)) {
8257                 /* page got truncated out from underneath us */
8258                 goto out_unlock;
8259         }
8260         wait_on_page_writeback(page);
8261
8262         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
8263         set_page_extent_mapped(page);
8264
8265         /*
8266          * we can't set the delalloc bits if there are pending ordered
8267          * extents.  Drop our locks and wait for them to finish
8268          */
8269         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8270         if (ordered) {
8271                 unlock_extent_cached(io_tree, page_start, page_end,
8272                                      &cached_state, GFP_NOFS);
8273                 unlock_page(page);
8274                 btrfs_start_ordered_extent(inode, ordered, 1);
8275                 btrfs_put_ordered_extent(ordered);
8276                 goto again;
8277         }
8278
8279         /*
8280          * XXX - page_mkwrite gets called every time the page is dirtied, even
8281          * if it was already dirty, so for space accounting reasons we need to
8282          * clear any delalloc bits for the range we are fixing to save.  There
8283          * is probably a better way to do this, but for now keep consistent with
8284          * prepare_pages in the normal write path.
8285          */
8286         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
8287                           EXTENT_DIRTY | EXTENT_DELALLOC |
8288                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8289                           0, 0, &cached_state, GFP_NOFS);
8290
8291         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
8292                                         &cached_state);
8293         if (ret) {
8294                 unlock_extent_cached(io_tree, page_start, page_end,
8295                                      &cached_state, GFP_NOFS);
8296                 ret = VM_FAULT_SIGBUS;
8297                 goto out_unlock;
8298         }
8299         ret = 0;
8300
8301         /* page is wholly or partially inside EOF */
8302         if (page_start + PAGE_CACHE_SIZE > size)
8303                 zero_start = size & ~PAGE_CACHE_MASK;
8304         else
8305                 zero_start = PAGE_CACHE_SIZE;
8306
8307         if (zero_start != PAGE_CACHE_SIZE) {
8308                 kaddr = kmap(page);
8309                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
8310                 flush_dcache_page(page);
8311                 kunmap(page);
8312         }
8313         ClearPageChecked(page);
8314         set_page_dirty(page);
8315         SetPageUptodate(page);
8316
8317         BTRFS_I(inode)->last_trans = root->fs_info->generation;
8318         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8319         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8320
8321         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
8322
8323 out_unlock:
8324         if (!ret) {
8325                 sb_end_pagefault(inode->i_sb);
8326                 return VM_FAULT_LOCKED;
8327         }
8328         unlock_page(page);
8329 out:
8330         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
8331 out_noreserve:
8332         sb_end_pagefault(inode->i_sb);
8333         return ret;
8334 }
8335
8336 static int btrfs_truncate(struct inode *inode)
8337 {
8338         struct btrfs_root *root = BTRFS_I(inode)->root;
8339         struct btrfs_block_rsv *rsv;
8340         int ret = 0;
8341         int err = 0;
8342         struct btrfs_trans_handle *trans;
8343         u64 mask = root->sectorsize - 1;
8344         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
8345
8346         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8347                                        (u64)-1);
8348         if (ret)
8349                 return ret;
8350
8351         /*
8352          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
8353          * 3 things going on here
8354          *
8355          * 1) We need to reserve space for our orphan item and the space to
8356          * delete our orphan item.  Lord knows we don't want to have a dangling
8357          * orphan item because we didn't reserve space to remove it.
8358          *
8359          * 2) We need to reserve space to update our inode.
8360          *
8361          * 3) We need to have something to cache all the space that is going to
8362          * be free'd up by the truncate operation, but also have some slack
8363          * space reserved in case it uses space during the truncate (thank you
8364          * very much snapshotting).
8365          *
8366          * And we need these to all be seperate.  The fact is we can use alot of
8367          * space doing the truncate, and we have no earthly idea how much space
8368          * we will use, so we need the truncate reservation to be seperate so it
8369          * doesn't end up using space reserved for updating the inode or
8370          * removing the orphan item.  We also need to be able to stop the
8371          * transaction and start a new one, which means we need to be able to
8372          * update the inode several times, and we have no idea of knowing how
8373          * many times that will be, so we can't just reserve 1 item for the
8374          * entirety of the opration, so that has to be done seperately as well.
8375          * Then there is the orphan item, which does indeed need to be held on
8376          * to for the whole operation, and we need nobody to touch this reserved
8377          * space except the orphan code.
8378          *
8379          * So that leaves us with
8380          *
8381          * 1) root->orphan_block_rsv - for the orphan deletion.
8382          * 2) rsv - for the truncate reservation, which we will steal from the
8383          * transaction reservation.
8384          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
8385          * updating the inode.
8386          */
8387         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
8388         if (!rsv)
8389                 return -ENOMEM;
8390         rsv->size = min_size;
8391         rsv->failfast = 1;
8392
8393         /*
8394          * 1 for the truncate slack space
8395          * 1 for updating the inode.
8396          */
8397         trans = btrfs_start_transaction(root, 2);
8398         if (IS_ERR(trans)) {
8399                 err = PTR_ERR(trans);
8400                 goto out;
8401         }
8402
8403         /* Migrate the slack space for the truncate to our reserve */
8404         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
8405                                       min_size);
8406         BUG_ON(ret);
8407
8408         /*
8409          * So if we truncate and then write and fsync we normally would just
8410          * write the extents that changed, which is a problem if we need to
8411          * first truncate that entire inode.  So set this flag so we write out
8412          * all of the extents in the inode to the sync log so we're completely
8413          * safe.
8414          */
8415         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
8416         trans->block_rsv = rsv;
8417
8418         while (1) {
8419                 ret = btrfs_truncate_inode_items(trans, root, inode,
8420                                                  inode->i_size,
8421                                                  BTRFS_EXTENT_DATA_KEY);
8422                 if (ret != -ENOSPC) {
8423                         err = ret;
8424                         break;
8425                 }
8426
8427                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8428                 ret = btrfs_update_inode(trans, root, inode);
8429                 if (ret) {
8430                         err = ret;
8431                         break;
8432                 }
8433
8434                 btrfs_end_transaction(trans, root);
8435                 btrfs_btree_balance_dirty(root);
8436
8437                 trans = btrfs_start_transaction(root, 2);
8438                 if (IS_ERR(trans)) {
8439                         ret = err = PTR_ERR(trans);
8440                         trans = NULL;
8441                         break;
8442                 }
8443
8444                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
8445                                               rsv, min_size);
8446                 BUG_ON(ret);    /* shouldn't happen */
8447                 trans->block_rsv = rsv;
8448         }
8449
8450         if (ret == 0 && inode->i_nlink > 0) {
8451                 trans->block_rsv = root->orphan_block_rsv;
8452                 ret = btrfs_orphan_del(trans, inode);
8453                 if (ret)
8454                         err = ret;
8455         }
8456
8457         if (trans) {
8458                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8459                 ret = btrfs_update_inode(trans, root, inode);
8460                 if (ret && !err)
8461                         err = ret;
8462
8463                 ret = btrfs_end_transaction(trans, root);
8464                 btrfs_btree_balance_dirty(root);
8465         }
8466
8467 out:
8468         btrfs_free_block_rsv(root, rsv);
8469
8470         if (ret && !err)
8471                 err = ret;
8472
8473         return err;
8474 }
8475
8476 /*
8477  * create a new subvolume directory/inode (helper for the ioctl).
8478  */
8479 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8480                              struct btrfs_root *new_root,
8481                              struct btrfs_root *parent_root,
8482                              u64 new_dirid)
8483 {
8484         struct inode *inode;
8485         int err;
8486         u64 index = 0;
8487
8488         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8489                                 new_dirid, new_dirid,
8490                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8491                                 &index);
8492         if (IS_ERR(inode))
8493                 return PTR_ERR(inode);
8494         inode->i_op = &btrfs_dir_inode_operations;
8495         inode->i_fop = &btrfs_dir_file_operations;
8496
8497         set_nlink(inode, 1);
8498         btrfs_i_size_write(inode, 0);
8499         unlock_new_inode(inode);
8500
8501         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8502         if (err)
8503                 btrfs_err(new_root->fs_info,
8504                           "error inheriting subvolume %llu properties: %d",
8505                           new_root->root_key.objectid, err);
8506
8507         err = btrfs_update_inode(trans, new_root, inode);
8508
8509         iput(inode);
8510         return err;
8511 }
8512
8513 struct inode *btrfs_alloc_inode(struct super_block *sb)
8514 {
8515         struct btrfs_inode *ei;
8516         struct inode *inode;
8517
8518         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
8519         if (!ei)
8520                 return NULL;
8521
8522         ei->root = NULL;
8523         ei->generation = 0;
8524         ei->last_trans = 0;
8525         ei->last_sub_trans = 0;
8526         ei->logged_trans = 0;
8527         ei->delalloc_bytes = 0;
8528         ei->defrag_bytes = 0;
8529         ei->disk_i_size = 0;
8530         ei->flags = 0;
8531         ei->csum_bytes = 0;
8532         ei->index_cnt = (u64)-1;
8533         ei->dir_index = 0;
8534         ei->last_unlink_trans = 0;
8535         ei->last_log_commit = 0;
8536
8537         spin_lock_init(&ei->lock);
8538         ei->outstanding_extents = 0;
8539         ei->reserved_extents = 0;
8540
8541         ei->runtime_flags = 0;
8542         ei->force_compress = BTRFS_COMPRESS_NONE;
8543
8544         ei->delayed_node = NULL;
8545
8546         inode = &ei->vfs_inode;
8547         extent_map_tree_init(&ei->extent_tree);
8548         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8549         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8550         ei->io_tree.track_uptodate = 1;
8551         ei->io_failure_tree.track_uptodate = 1;
8552         atomic_set(&ei->sync_writers, 0);
8553         mutex_init(&ei->log_mutex);
8554         mutex_init(&ei->delalloc_mutex);
8555         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8556         INIT_LIST_HEAD(&ei->delalloc_inodes);
8557         RB_CLEAR_NODE(&ei->rb_node);
8558
8559         return inode;
8560 }
8561
8562 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8563 void btrfs_test_destroy_inode(struct inode *inode)
8564 {
8565         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8566         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8567 }
8568 #endif
8569
8570 static void btrfs_i_callback(struct rcu_head *head)
8571 {
8572         struct inode *inode = container_of(head, struct inode, i_rcu);
8573         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8574 }
8575
8576 void btrfs_destroy_inode(struct inode *inode)
8577 {
8578         struct btrfs_ordered_extent *ordered;
8579         struct btrfs_root *root = BTRFS_I(inode)->root;
8580
8581         WARN_ON(!hlist_empty(&inode->i_dentry));
8582         WARN_ON(inode->i_data.nrpages);
8583         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8584         WARN_ON(BTRFS_I(inode)->reserved_extents);
8585         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8586         WARN_ON(BTRFS_I(inode)->csum_bytes);
8587         WARN_ON(BTRFS_I(inode)->defrag_bytes);
8588
8589         /*
8590          * This can happen where we create an inode, but somebody else also
8591          * created the same inode and we need to destroy the one we already
8592          * created.
8593          */
8594         if (!root)
8595                 goto free;
8596
8597         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8598                      &BTRFS_I(inode)->runtime_flags)) {
8599                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8600                         btrfs_ino(inode));
8601                 atomic_dec(&root->orphan_inodes);
8602         }
8603
8604         while (1) {
8605                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8606                 if (!ordered)
8607                         break;
8608                 else {
8609                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8610                                 ordered->file_offset, ordered->len);
8611                         btrfs_remove_ordered_extent(inode, ordered);
8612                         btrfs_put_ordered_extent(ordered);
8613                         btrfs_put_ordered_extent(ordered);
8614                 }
8615         }
8616         inode_tree_del(inode);
8617         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8618 free:
8619         call_rcu(&inode->i_rcu, btrfs_i_callback);
8620 }
8621
8622 int btrfs_drop_inode(struct inode *inode)
8623 {
8624         struct btrfs_root *root = BTRFS_I(inode)->root;
8625
8626         if (root == NULL)
8627                 return 1;
8628
8629         /* the snap/subvol tree is on deleting */
8630         if (btrfs_root_refs(&root->root_item) == 0)
8631                 return 1;
8632         else
8633                 return generic_drop_inode(inode);
8634 }
8635
8636 static void init_once(void *foo)
8637 {
8638         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8639
8640         inode_init_once(&ei->vfs_inode);
8641 }
8642
8643 void btrfs_destroy_cachep(void)
8644 {
8645         /*
8646          * Make sure all delayed rcu free inodes are flushed before we
8647          * destroy cache.
8648          */
8649         rcu_barrier();
8650         if (btrfs_inode_cachep)
8651                 kmem_cache_destroy(btrfs_inode_cachep);
8652         if (btrfs_trans_handle_cachep)
8653                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8654         if (btrfs_transaction_cachep)
8655                 kmem_cache_destroy(btrfs_transaction_cachep);
8656         if (btrfs_path_cachep)
8657                 kmem_cache_destroy(btrfs_path_cachep);
8658         if (btrfs_free_space_cachep)
8659                 kmem_cache_destroy(btrfs_free_space_cachep);
8660         if (btrfs_delalloc_work_cachep)
8661                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8662 }
8663
8664 int btrfs_init_cachep(void)
8665 {
8666         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8667                         sizeof(struct btrfs_inode), 0,
8668                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8669         if (!btrfs_inode_cachep)
8670                 goto fail;
8671
8672         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8673                         sizeof(struct btrfs_trans_handle), 0,
8674                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8675         if (!btrfs_trans_handle_cachep)
8676                 goto fail;
8677
8678         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8679                         sizeof(struct btrfs_transaction), 0,
8680                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8681         if (!btrfs_transaction_cachep)
8682                 goto fail;
8683
8684         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8685                         sizeof(struct btrfs_path), 0,
8686                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8687         if (!btrfs_path_cachep)
8688                 goto fail;
8689
8690         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8691                         sizeof(struct btrfs_free_space), 0,
8692                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8693         if (!btrfs_free_space_cachep)
8694                 goto fail;
8695
8696         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8697                         sizeof(struct btrfs_delalloc_work), 0,
8698                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8699                         NULL);
8700         if (!btrfs_delalloc_work_cachep)
8701                 goto fail;
8702
8703         return 0;
8704 fail:
8705         btrfs_destroy_cachep();
8706         return -ENOMEM;
8707 }
8708
8709 static int btrfs_getattr(struct vfsmount *mnt,
8710                          struct dentry *dentry, struct kstat *stat)
8711 {
8712         u64 delalloc_bytes;
8713         struct inode *inode = dentry->d_inode;
8714         u32 blocksize = inode->i_sb->s_blocksize;
8715
8716         generic_fillattr(inode, stat);
8717         stat->dev = BTRFS_I(inode)->root->anon_dev;
8718         stat->blksize = PAGE_CACHE_SIZE;
8719
8720         spin_lock(&BTRFS_I(inode)->lock);
8721         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8722         spin_unlock(&BTRFS_I(inode)->lock);
8723         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8724                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8725         return 0;
8726 }
8727
8728 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8729                            struct inode *new_dir, struct dentry *new_dentry)
8730 {
8731         struct btrfs_trans_handle *trans;
8732         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8733         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8734         struct inode *new_inode = new_dentry->d_inode;
8735         struct inode *old_inode = old_dentry->d_inode;
8736         struct timespec ctime = CURRENT_TIME;
8737         u64 index = 0;
8738         u64 root_objectid;
8739         int ret;
8740         u64 old_ino = btrfs_ino(old_inode);
8741
8742         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8743                 return -EPERM;
8744
8745         /* we only allow rename subvolume link between subvolumes */
8746         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8747                 return -EXDEV;
8748
8749         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8750             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8751                 return -ENOTEMPTY;
8752
8753         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8754             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8755                 return -ENOTEMPTY;
8756
8757
8758         /* check for collisions, even if the  name isn't there */
8759         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8760                              new_dentry->d_name.name,
8761                              new_dentry->d_name.len);
8762
8763         if (ret) {
8764                 if (ret == -EEXIST) {
8765                         /* we shouldn't get
8766                          * eexist without a new_inode */
8767                         if (WARN_ON(!new_inode)) {
8768                                 return ret;
8769                         }
8770                 } else {
8771                         /* maybe -EOVERFLOW */
8772                         return ret;
8773                 }
8774         }
8775         ret = 0;
8776
8777         /*
8778          * we're using rename to replace one file with another.  Start IO on it
8779          * now so  we don't add too much work to the end of the transaction
8780          */
8781         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
8782                 filemap_flush(old_inode->i_mapping);
8783
8784         /* close the racy window with snapshot create/destroy ioctl */
8785         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8786                 down_read(&root->fs_info->subvol_sem);
8787         /*
8788          * We want to reserve the absolute worst case amount of items.  So if
8789          * both inodes are subvols and we need to unlink them then that would
8790          * require 4 item modifications, but if they are both normal inodes it
8791          * would require 5 item modifications, so we'll assume their normal
8792          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8793          * should cover the worst case number of items we'll modify.
8794          */
8795         trans = btrfs_start_transaction(root, 11);
8796         if (IS_ERR(trans)) {
8797                 ret = PTR_ERR(trans);
8798                 goto out_notrans;
8799         }
8800
8801         if (dest != root)
8802                 btrfs_record_root_in_trans(trans, dest);
8803
8804         ret = btrfs_set_inode_index(new_dir, &index);
8805         if (ret)
8806                 goto out_fail;
8807
8808         BTRFS_I(old_inode)->dir_index = 0ULL;
8809         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8810                 /* force full log commit if subvolume involved. */
8811                 btrfs_set_log_full_commit(root->fs_info, trans);
8812         } else {
8813                 ret = btrfs_insert_inode_ref(trans, dest,
8814                                              new_dentry->d_name.name,
8815                                              new_dentry->d_name.len,
8816                                              old_ino,
8817                                              btrfs_ino(new_dir), index);
8818                 if (ret)
8819                         goto out_fail;
8820                 /*
8821                  * this is an ugly little race, but the rename is required
8822                  * to make sure that if we crash, the inode is either at the
8823                  * old name or the new one.  pinning the log transaction lets
8824                  * us make sure we don't allow a log commit to come in after
8825                  * we unlink the name but before we add the new name back in.
8826                  */
8827                 btrfs_pin_log_trans(root);
8828         }
8829
8830         inode_inc_iversion(old_dir);
8831         inode_inc_iversion(new_dir);
8832         inode_inc_iversion(old_inode);
8833         old_dir->i_ctime = old_dir->i_mtime = ctime;
8834         new_dir->i_ctime = new_dir->i_mtime = ctime;
8835         old_inode->i_ctime = ctime;
8836
8837         if (old_dentry->d_parent != new_dentry->d_parent)
8838                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8839
8840         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8841                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8842                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8843                                         old_dentry->d_name.name,
8844                                         old_dentry->d_name.len);
8845         } else {
8846                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8847                                         old_dentry->d_inode,
8848                                         old_dentry->d_name.name,
8849                                         old_dentry->d_name.len);
8850                 if (!ret)
8851                         ret = btrfs_update_inode(trans, root, old_inode);
8852         }
8853         if (ret) {
8854                 btrfs_abort_transaction(trans, root, ret);
8855                 goto out_fail;
8856         }
8857
8858         if (new_inode) {
8859                 inode_inc_iversion(new_inode);
8860                 new_inode->i_ctime = CURRENT_TIME;
8861                 if (unlikely(btrfs_ino(new_inode) ==
8862                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8863                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8864                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8865                                                 root_objectid,
8866                                                 new_dentry->d_name.name,
8867                                                 new_dentry->d_name.len);
8868                         BUG_ON(new_inode->i_nlink == 0);
8869                 } else {
8870                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8871                                                  new_dentry->d_inode,
8872                                                  new_dentry->d_name.name,
8873                                                  new_dentry->d_name.len);
8874                 }
8875                 if (!ret && new_inode->i_nlink == 0)
8876                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8877                 if (ret) {
8878                         btrfs_abort_transaction(trans, root, ret);
8879                         goto out_fail;
8880                 }
8881         }
8882
8883         ret = btrfs_add_link(trans, new_dir, old_inode,
8884                              new_dentry->d_name.name,
8885                              new_dentry->d_name.len, 0, index);
8886         if (ret) {
8887                 btrfs_abort_transaction(trans, root, ret);
8888                 goto out_fail;
8889         }
8890
8891         if (old_inode->i_nlink == 1)
8892                 BTRFS_I(old_inode)->dir_index = index;
8893
8894         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8895                 struct dentry *parent = new_dentry->d_parent;
8896                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8897                 btrfs_end_log_trans(root);
8898         }
8899 out_fail:
8900         btrfs_end_transaction(trans, root);
8901 out_notrans:
8902         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8903                 up_read(&root->fs_info->subvol_sem);
8904
8905         return ret;
8906 }
8907
8908 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
8909                          struct inode *new_dir, struct dentry *new_dentry,
8910                          unsigned int flags)
8911 {
8912         if (flags & ~RENAME_NOREPLACE)
8913                 return -EINVAL;
8914
8915         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry);
8916 }
8917
8918 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8919 {
8920         struct btrfs_delalloc_work *delalloc_work;
8921         struct inode *inode;
8922
8923         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8924                                      work);
8925         inode = delalloc_work->inode;
8926         if (delalloc_work->wait) {
8927                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8928         } else {
8929                 filemap_flush(inode->i_mapping);
8930                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8931                              &BTRFS_I(inode)->runtime_flags))
8932                         filemap_flush(inode->i_mapping);
8933         }
8934
8935         if (delalloc_work->delay_iput)
8936                 btrfs_add_delayed_iput(inode);
8937         else
8938                 iput(inode);
8939         complete(&delalloc_work->completion);
8940 }
8941
8942 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8943                                                     int wait, int delay_iput)
8944 {
8945         struct btrfs_delalloc_work *work;
8946
8947         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8948         if (!work)
8949                 return NULL;
8950
8951         init_completion(&work->completion);
8952         INIT_LIST_HEAD(&work->list);
8953         work->inode = inode;
8954         work->wait = wait;
8955         work->delay_iput = delay_iput;
8956         WARN_ON_ONCE(!inode);
8957         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
8958                         btrfs_run_delalloc_work, NULL, NULL);
8959
8960         return work;
8961 }
8962
8963 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8964 {
8965         wait_for_completion(&work->completion);
8966         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8967 }
8968
8969 /*
8970  * some fairly slow code that needs optimization. This walks the list
8971  * of all the inodes with pending delalloc and forces them to disk.
8972  */
8973 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
8974                                    int nr)
8975 {
8976         struct btrfs_inode *binode;
8977         struct inode *inode;
8978         struct btrfs_delalloc_work *work, *next;
8979         struct list_head works;
8980         struct list_head splice;
8981         int ret = 0;
8982
8983         INIT_LIST_HEAD(&works);
8984         INIT_LIST_HEAD(&splice);
8985
8986         mutex_lock(&root->delalloc_mutex);
8987         spin_lock(&root->delalloc_lock);
8988         list_splice_init(&root->delalloc_inodes, &splice);
8989         while (!list_empty(&splice)) {
8990                 binode = list_entry(splice.next, struct btrfs_inode,
8991                                     delalloc_inodes);
8992
8993                 list_move_tail(&binode->delalloc_inodes,
8994                                &root->delalloc_inodes);
8995                 inode = igrab(&binode->vfs_inode);
8996                 if (!inode) {
8997                         cond_resched_lock(&root->delalloc_lock);
8998                         continue;
8999                 }
9000                 spin_unlock(&root->delalloc_lock);
9001
9002                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
9003                 if (!work) {
9004                         if (delay_iput)
9005                                 btrfs_add_delayed_iput(inode);
9006                         else
9007                                 iput(inode);
9008                         ret = -ENOMEM;
9009                         goto out;
9010                 }
9011                 list_add_tail(&work->list, &works);
9012                 btrfs_queue_work(root->fs_info->flush_workers,
9013                                  &work->work);
9014                 ret++;
9015                 if (nr != -1 && ret >= nr)
9016                         goto out;
9017                 cond_resched();
9018                 spin_lock(&root->delalloc_lock);
9019         }
9020         spin_unlock(&root->delalloc_lock);
9021
9022 out:
9023         list_for_each_entry_safe(work, next, &works, list) {
9024                 list_del_init(&work->list);
9025                 btrfs_wait_and_free_delalloc_work(work);
9026         }
9027
9028         if (!list_empty_careful(&splice)) {
9029                 spin_lock(&root->delalloc_lock);
9030                 list_splice_tail(&splice, &root->delalloc_inodes);
9031                 spin_unlock(&root->delalloc_lock);
9032         }
9033         mutex_unlock(&root->delalloc_mutex);
9034         return ret;
9035 }
9036
9037 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
9038 {
9039         int ret;
9040
9041         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
9042                 return -EROFS;
9043
9044         ret = __start_delalloc_inodes(root, delay_iput, -1);
9045         if (ret > 0)
9046                 ret = 0;
9047         /*
9048          * the filemap_flush will queue IO into the worker threads, but
9049          * we have to make sure the IO is actually started and that
9050          * ordered extents get created before we return
9051          */
9052         atomic_inc(&root->fs_info->async_submit_draining);
9053         while (atomic_read(&root->fs_info->nr_async_submits) ||
9054               atomic_read(&root->fs_info->async_delalloc_pages)) {
9055                 wait_event(root->fs_info->async_submit_wait,
9056                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
9057                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
9058         }
9059         atomic_dec(&root->fs_info->async_submit_draining);
9060         return ret;
9061 }
9062
9063 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
9064                                int nr)
9065 {
9066         struct btrfs_root *root;
9067         struct list_head splice;
9068         int ret;
9069
9070         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9071                 return -EROFS;
9072
9073         INIT_LIST_HEAD(&splice);
9074
9075         mutex_lock(&fs_info->delalloc_root_mutex);
9076         spin_lock(&fs_info->delalloc_root_lock);
9077         list_splice_init(&fs_info->delalloc_roots, &splice);
9078         while (!list_empty(&splice) && nr) {
9079                 root = list_first_entry(&splice, struct btrfs_root,
9080                                         delalloc_root);
9081                 root = btrfs_grab_fs_root(root);
9082                 BUG_ON(!root);
9083                 list_move_tail(&root->delalloc_root,
9084                                &fs_info->delalloc_roots);
9085                 spin_unlock(&fs_info->delalloc_root_lock);
9086
9087                 ret = __start_delalloc_inodes(root, delay_iput, nr);
9088                 btrfs_put_fs_root(root);
9089                 if (ret < 0)
9090                         goto out;
9091
9092                 if (nr != -1) {
9093                         nr -= ret;
9094                         WARN_ON(nr < 0);
9095                 }
9096                 spin_lock(&fs_info->delalloc_root_lock);
9097         }
9098         spin_unlock(&fs_info->delalloc_root_lock);
9099
9100         ret = 0;
9101         atomic_inc(&fs_info->async_submit_draining);
9102         while (atomic_read(&fs_info->nr_async_submits) ||
9103               atomic_read(&fs_info->async_delalloc_pages)) {
9104                 wait_event(fs_info->async_submit_wait,
9105                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
9106                     atomic_read(&fs_info->async_delalloc_pages) == 0));
9107         }
9108         atomic_dec(&fs_info->async_submit_draining);
9109 out:
9110         if (!list_empty_careful(&splice)) {
9111                 spin_lock(&fs_info->delalloc_root_lock);
9112                 list_splice_tail(&splice, &fs_info->delalloc_roots);
9113                 spin_unlock(&fs_info->delalloc_root_lock);
9114         }
9115         mutex_unlock(&fs_info->delalloc_root_mutex);
9116         return ret;
9117 }
9118
9119 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
9120                          const char *symname)
9121 {
9122         struct btrfs_trans_handle *trans;
9123         struct btrfs_root *root = BTRFS_I(dir)->root;
9124         struct btrfs_path *path;
9125         struct btrfs_key key;
9126         struct inode *inode = NULL;
9127         int err;
9128         int drop_inode = 0;
9129         u64 objectid;
9130         u64 index = 0;
9131         int name_len;
9132         int datasize;
9133         unsigned long ptr;
9134         struct btrfs_file_extent_item *ei;
9135         struct extent_buffer *leaf;
9136
9137         name_len = strlen(symname);
9138         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
9139                 return -ENAMETOOLONG;
9140
9141         /*
9142          * 2 items for inode item and ref
9143          * 2 items for dir items
9144          * 1 item for xattr if selinux is on
9145          */
9146         trans = btrfs_start_transaction(root, 5);
9147         if (IS_ERR(trans))
9148                 return PTR_ERR(trans);
9149
9150         err = btrfs_find_free_ino(root, &objectid);
9151         if (err)
9152                 goto out_unlock;
9153
9154         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
9155                                 dentry->d_name.len, btrfs_ino(dir), objectid,
9156                                 S_IFLNK|S_IRWXUGO, &index);
9157         if (IS_ERR(inode)) {
9158                 err = PTR_ERR(inode);
9159                 goto out_unlock;
9160         }
9161
9162         /*
9163         * If the active LSM wants to access the inode during
9164         * d_instantiate it needs these. Smack checks to see
9165         * if the filesystem supports xattrs by looking at the
9166         * ops vector.
9167         */
9168         inode->i_fop = &btrfs_file_operations;
9169         inode->i_op = &btrfs_file_inode_operations;
9170         inode->i_mapping->a_ops = &btrfs_aops;
9171         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9172         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9173
9174         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
9175         if (err)
9176                 goto out_unlock_inode;
9177
9178         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
9179         if (err)
9180                 goto out_unlock_inode;
9181
9182         path = btrfs_alloc_path();
9183         if (!path) {
9184                 err = -ENOMEM;
9185                 goto out_unlock_inode;
9186         }
9187         key.objectid = btrfs_ino(inode);
9188         key.offset = 0;
9189         key.type = BTRFS_EXTENT_DATA_KEY;
9190         datasize = btrfs_file_extent_calc_inline_size(name_len);
9191         err = btrfs_insert_empty_item(trans, root, path, &key,
9192                                       datasize);
9193         if (err) {
9194                 btrfs_free_path(path);
9195                 goto out_unlock_inode;
9196         }
9197         leaf = path->nodes[0];
9198         ei = btrfs_item_ptr(leaf, path->slots[0],
9199                             struct btrfs_file_extent_item);
9200         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
9201         btrfs_set_file_extent_type(leaf, ei,
9202                                    BTRFS_FILE_EXTENT_INLINE);
9203         btrfs_set_file_extent_encryption(leaf, ei, 0);
9204         btrfs_set_file_extent_compression(leaf, ei, 0);
9205         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
9206         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
9207
9208         ptr = btrfs_file_extent_inline_start(ei);
9209         write_extent_buffer(leaf, symname, ptr, name_len);
9210         btrfs_mark_buffer_dirty(leaf);
9211         btrfs_free_path(path);
9212
9213         inode->i_op = &btrfs_symlink_inode_operations;
9214         inode->i_mapping->a_ops = &btrfs_symlink_aops;
9215         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9216         inode_set_bytes(inode, name_len);
9217         btrfs_i_size_write(inode, name_len);
9218         err = btrfs_update_inode(trans, root, inode);
9219         if (err) {
9220                 drop_inode = 1;
9221                 goto out_unlock_inode;
9222         }
9223
9224         unlock_new_inode(inode);
9225         d_instantiate(dentry, inode);
9226
9227 out_unlock:
9228         btrfs_end_transaction(trans, root);
9229         if (drop_inode) {
9230                 inode_dec_link_count(inode);
9231                 iput(inode);
9232         }
9233         btrfs_btree_balance_dirty(root);
9234         return err;
9235
9236 out_unlock_inode:
9237         drop_inode = 1;
9238         unlock_new_inode(inode);
9239         goto out_unlock;
9240 }
9241
9242 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
9243                                        u64 start, u64 num_bytes, u64 min_size,
9244                                        loff_t actual_len, u64 *alloc_hint,
9245                                        struct btrfs_trans_handle *trans)
9246 {
9247         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
9248         struct extent_map *em;
9249         struct btrfs_root *root = BTRFS_I(inode)->root;
9250         struct btrfs_key ins;
9251         u64 cur_offset = start;
9252         u64 i_size;
9253         u64 cur_bytes;
9254         int ret = 0;
9255         bool own_trans = true;
9256
9257         if (trans)
9258                 own_trans = false;
9259         while (num_bytes > 0) {
9260                 if (own_trans) {
9261                         trans = btrfs_start_transaction(root, 3);
9262                         if (IS_ERR(trans)) {
9263                                 ret = PTR_ERR(trans);
9264                                 break;
9265                         }
9266                 }
9267
9268                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
9269                 cur_bytes = max(cur_bytes, min_size);
9270                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
9271                                            *alloc_hint, &ins, 1, 0);
9272                 if (ret) {
9273                         if (own_trans)
9274                                 btrfs_end_transaction(trans, root);
9275                         break;
9276                 }
9277
9278                 ret = insert_reserved_file_extent(trans, inode,
9279                                                   cur_offset, ins.objectid,
9280                                                   ins.offset, ins.offset,
9281                                                   ins.offset, 0, 0, 0,
9282                                                   BTRFS_FILE_EXTENT_PREALLOC);
9283                 if (ret) {
9284                         btrfs_free_reserved_extent(root, ins.objectid,
9285                                                    ins.offset, 0);
9286                         btrfs_abort_transaction(trans, root, ret);
9287                         if (own_trans)
9288                                 btrfs_end_transaction(trans, root);
9289                         break;
9290                 }
9291                 btrfs_drop_extent_cache(inode, cur_offset,
9292                                         cur_offset + ins.offset -1, 0);
9293
9294                 em = alloc_extent_map();
9295                 if (!em) {
9296                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
9297                                 &BTRFS_I(inode)->runtime_flags);
9298                         goto next;
9299                 }
9300
9301                 em->start = cur_offset;
9302                 em->orig_start = cur_offset;
9303                 em->len = ins.offset;
9304                 em->block_start = ins.objectid;
9305                 em->block_len = ins.offset;
9306                 em->orig_block_len = ins.offset;
9307                 em->ram_bytes = ins.offset;
9308                 em->bdev = root->fs_info->fs_devices->latest_bdev;
9309                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
9310                 em->generation = trans->transid;
9311
9312                 while (1) {
9313                         write_lock(&em_tree->lock);
9314                         ret = add_extent_mapping(em_tree, em, 1);
9315                         write_unlock(&em_tree->lock);
9316                         if (ret != -EEXIST)
9317                                 break;
9318                         btrfs_drop_extent_cache(inode, cur_offset,
9319                                                 cur_offset + ins.offset - 1,
9320                                                 0);
9321                 }
9322                 free_extent_map(em);
9323 next:
9324                 num_bytes -= ins.offset;
9325                 cur_offset += ins.offset;
9326                 *alloc_hint = ins.objectid + ins.offset;
9327
9328                 inode_inc_iversion(inode);
9329                 inode->i_ctime = CURRENT_TIME;
9330                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
9331                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
9332                     (actual_len > inode->i_size) &&
9333                     (cur_offset > inode->i_size)) {
9334                         if (cur_offset > actual_len)
9335                                 i_size = actual_len;
9336                         else
9337                                 i_size = cur_offset;
9338                         i_size_write(inode, i_size);
9339                         btrfs_ordered_update_i_size(inode, i_size, NULL);
9340                 }
9341
9342                 ret = btrfs_update_inode(trans, root, inode);
9343
9344                 if (ret) {
9345                         btrfs_abort_transaction(trans, root, ret);
9346                         if (own_trans)
9347                                 btrfs_end_transaction(trans, root);
9348                         break;
9349                 }
9350
9351                 if (own_trans)
9352                         btrfs_end_transaction(trans, root);
9353         }
9354         return ret;
9355 }
9356
9357 int btrfs_prealloc_file_range(struct inode *inode, int mode,
9358                               u64 start, u64 num_bytes, u64 min_size,
9359                               loff_t actual_len, u64 *alloc_hint)
9360 {
9361         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9362                                            min_size, actual_len, alloc_hint,
9363                                            NULL);
9364 }
9365
9366 int btrfs_prealloc_file_range_trans(struct inode *inode,
9367                                     struct btrfs_trans_handle *trans, int mode,
9368                                     u64 start, u64 num_bytes, u64 min_size,
9369                                     loff_t actual_len, u64 *alloc_hint)
9370 {
9371         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9372                                            min_size, actual_len, alloc_hint, trans);
9373 }
9374
9375 static int btrfs_set_page_dirty(struct page *page)
9376 {
9377         return __set_page_dirty_nobuffers(page);
9378 }
9379
9380 static int btrfs_permission(struct inode *inode, int mask)
9381 {
9382         struct btrfs_root *root = BTRFS_I(inode)->root;
9383         umode_t mode = inode->i_mode;
9384
9385         if (mask & MAY_WRITE &&
9386             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
9387                 if (btrfs_root_readonly(root))
9388                         return -EROFS;
9389                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
9390                         return -EACCES;
9391         }
9392         return generic_permission(inode, mask);
9393 }
9394
9395 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
9396 {
9397         struct btrfs_trans_handle *trans;
9398         struct btrfs_root *root = BTRFS_I(dir)->root;
9399         struct inode *inode = NULL;
9400         u64 objectid;
9401         u64 index;
9402         int ret = 0;
9403
9404         /*
9405          * 5 units required for adding orphan entry
9406          */
9407         trans = btrfs_start_transaction(root, 5);
9408         if (IS_ERR(trans))
9409                 return PTR_ERR(trans);
9410
9411         ret = btrfs_find_free_ino(root, &objectid);
9412         if (ret)
9413                 goto out;
9414
9415         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
9416                                 btrfs_ino(dir), objectid, mode, &index);
9417         if (IS_ERR(inode)) {
9418                 ret = PTR_ERR(inode);
9419                 inode = NULL;
9420                 goto out;
9421         }
9422
9423         inode->i_fop = &btrfs_file_operations;
9424         inode->i_op = &btrfs_file_inode_operations;
9425
9426         inode->i_mapping->a_ops = &btrfs_aops;
9427         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9428         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9429
9430         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
9431         if (ret)
9432                 goto out_inode;
9433
9434         ret = btrfs_update_inode(trans, root, inode);
9435         if (ret)
9436                 goto out_inode;
9437         ret = btrfs_orphan_add(trans, inode);
9438         if (ret)
9439                 goto out_inode;
9440
9441         /*
9442          * We set number of links to 0 in btrfs_new_inode(), and here we set
9443          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
9444          * through:
9445          *
9446          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
9447          */
9448         set_nlink(inode, 1);
9449         unlock_new_inode(inode);
9450         d_tmpfile(dentry, inode);
9451         mark_inode_dirty(inode);
9452
9453 out:
9454         btrfs_end_transaction(trans, root);
9455         if (ret)
9456                 iput(inode);
9457         btrfs_balance_delayed_items(root);
9458         btrfs_btree_balance_dirty(root);
9459         return ret;
9460
9461 out_inode:
9462         unlock_new_inode(inode);
9463         goto out;
9464
9465 }
9466
9467 static const struct inode_operations btrfs_dir_inode_operations = {
9468         .getattr        = btrfs_getattr,
9469         .lookup         = btrfs_lookup,
9470         .create         = btrfs_create,
9471         .unlink         = btrfs_unlink,
9472         .link           = btrfs_link,
9473         .mkdir          = btrfs_mkdir,
9474         .rmdir          = btrfs_rmdir,
9475         .rename2        = btrfs_rename2,
9476         .symlink        = btrfs_symlink,
9477         .setattr        = btrfs_setattr,
9478         .mknod          = btrfs_mknod,
9479         .setxattr       = btrfs_setxattr,
9480         .getxattr       = btrfs_getxattr,
9481         .listxattr      = btrfs_listxattr,
9482         .removexattr    = btrfs_removexattr,
9483         .permission     = btrfs_permission,
9484         .get_acl        = btrfs_get_acl,
9485         .set_acl        = btrfs_set_acl,
9486         .update_time    = btrfs_update_time,
9487         .tmpfile        = btrfs_tmpfile,
9488 };
9489 static const struct inode_operations btrfs_dir_ro_inode_operations = {
9490         .lookup         = btrfs_lookup,
9491         .permission     = btrfs_permission,
9492         .get_acl        = btrfs_get_acl,
9493         .set_acl        = btrfs_set_acl,
9494         .update_time    = btrfs_update_time,
9495 };
9496
9497 static const struct file_operations btrfs_dir_file_operations = {
9498         .llseek         = generic_file_llseek,
9499         .read           = generic_read_dir,
9500         .iterate        = btrfs_real_readdir,
9501         .unlocked_ioctl = btrfs_ioctl,
9502 #ifdef CONFIG_COMPAT
9503         .compat_ioctl   = btrfs_ioctl,
9504 #endif
9505         .release        = btrfs_release_file,
9506         .fsync          = btrfs_sync_file,
9507 };
9508
9509 static struct extent_io_ops btrfs_extent_io_ops = {
9510         .fill_delalloc = run_delalloc_range,
9511         .submit_bio_hook = btrfs_submit_bio_hook,
9512         .merge_bio_hook = btrfs_merge_bio_hook,
9513         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
9514         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
9515         .writepage_start_hook = btrfs_writepage_start_hook,
9516         .set_bit_hook = btrfs_set_bit_hook,
9517         .clear_bit_hook = btrfs_clear_bit_hook,
9518         .merge_extent_hook = btrfs_merge_extent_hook,
9519         .split_extent_hook = btrfs_split_extent_hook,
9520 };
9521
9522 /*
9523  * btrfs doesn't support the bmap operation because swapfiles
9524  * use bmap to make a mapping of extents in the file.  They assume
9525  * these extents won't change over the life of the file and they
9526  * use the bmap result to do IO directly to the drive.
9527  *
9528  * the btrfs bmap call would return logical addresses that aren't
9529  * suitable for IO and they also will change frequently as COW
9530  * operations happen.  So, swapfile + btrfs == corruption.
9531  *
9532  * For now we're avoiding this by dropping bmap.
9533  */
9534 static const struct address_space_operations btrfs_aops = {
9535         .readpage       = btrfs_readpage,
9536         .writepage      = btrfs_writepage,
9537         .writepages     = btrfs_writepages,
9538         .readpages      = btrfs_readpages,
9539         .direct_IO      = btrfs_direct_IO,
9540         .invalidatepage = btrfs_invalidatepage,
9541         .releasepage    = btrfs_releasepage,
9542         .set_page_dirty = btrfs_set_page_dirty,
9543         .error_remove_page = generic_error_remove_page,
9544 };
9545
9546 static const struct address_space_operations btrfs_symlink_aops = {
9547         .readpage       = btrfs_readpage,
9548         .writepage      = btrfs_writepage,
9549         .invalidatepage = btrfs_invalidatepage,
9550         .releasepage    = btrfs_releasepage,
9551 };
9552
9553 static const struct inode_operations btrfs_file_inode_operations = {
9554         .getattr        = btrfs_getattr,
9555         .setattr        = btrfs_setattr,
9556         .setxattr       = btrfs_setxattr,
9557         .getxattr       = btrfs_getxattr,
9558         .listxattr      = btrfs_listxattr,
9559         .removexattr    = btrfs_removexattr,
9560         .permission     = btrfs_permission,
9561         .fiemap         = btrfs_fiemap,
9562         .get_acl        = btrfs_get_acl,
9563         .set_acl        = btrfs_set_acl,
9564         .update_time    = btrfs_update_time,
9565 };
9566 static const struct inode_operations btrfs_special_inode_operations = {
9567         .getattr        = btrfs_getattr,
9568         .setattr        = btrfs_setattr,
9569         .permission     = btrfs_permission,
9570         .setxattr       = btrfs_setxattr,
9571         .getxattr       = btrfs_getxattr,
9572         .listxattr      = btrfs_listxattr,
9573         .removexattr    = btrfs_removexattr,
9574         .get_acl        = btrfs_get_acl,
9575         .set_acl        = btrfs_set_acl,
9576         .update_time    = btrfs_update_time,
9577 };
9578 static const struct inode_operations btrfs_symlink_inode_operations = {
9579         .readlink       = generic_readlink,
9580         .follow_link    = page_follow_link_light,
9581         .put_link       = page_put_link,
9582         .getattr        = btrfs_getattr,
9583         .setattr        = btrfs_setattr,
9584         .permission     = btrfs_permission,
9585         .setxattr       = btrfs_setxattr,
9586         .getxattr       = btrfs_getxattr,
9587         .listxattr      = btrfs_listxattr,
9588         .removexattr    = btrfs_removexattr,
9589         .update_time    = btrfs_update_time,
9590 };
9591
9592 const struct dentry_operations btrfs_dentry_operations = {
9593         .d_delete       = btrfs_dentry_delete,
9594         .d_release      = btrfs_dentry_release,
9595 };