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/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include "compat.h"
  40 #include "ctree.h"
  41 #include "disk-io.h"
  42 #include "transaction.h"
  43 #include "btrfs_inode.h"
  44 #include "ioctl.h"
  45 #include "print-tree.h"
  46 #include "volumes.h"
  47 #include "ordered-data.h"
  48 #include "xattr.h"
  49 #include "tree-log.h"
  50 #include "compression.h"
  51 #include "locking.h"
  52
  53 struct btrfs_iget_args {
  54         u64 ino;
  55         struct btrfs_root *root;
  56 };
  57
  58 static const struct inode_operations btrfs_dir_inode_operations;
  59 static const struct inode_operations btrfs_symlink_inode_operations;
  60 static const struct inode_operations btrfs_dir_ro_inode_operations;
  61 static const struct inode_operations btrfs_special_inode_operations;
  62 static const struct inode_operations btrfs_file_inode_operations;
  63 static const struct address_space_operations btrfs_aops;
  64 static const struct address_space_operations btrfs_symlink_aops;
  65 static struct file_operations btrfs_dir_file_operations;
  66 static struct extent_io_ops btrfs_extent_io_ops;
  67
  68 static struct kmem_cache *btrfs_inode_cachep;
  69 struct kmem_cache *btrfs_trans_handle_cachep;
  70 struct kmem_cache *btrfs_transaction_cachep;
  71 struct kmem_cache *btrfs_path_cachep;
  72
  73 #define S_SHIFT 12
  74 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  75         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  76         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  77         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  78         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  79         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  80         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  81         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  82 };
  83
  84 static void btrfs_truncate(struct inode *inode);
  85 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
  86 static noinline int cow_file_range(struct inode *inode,
  87                                    struct page *locked_page,
  88                                    u64 start, u64 end, int *page_started,
  89                                    unsigned long *nr_written, int unlock);
  90
  91 static int btrfs_init_inode_security(struct inode *inode,  struct inode *dir)
  92 {
  93         int err;
  94
  95         err = btrfs_init_acl(inode, dir);
  96         if (!err)
  97                 err = btrfs_xattr_security_init(inode, dir);
  98         return err;
  99 }
 100
 101 /*
 102  * this does all the hard work for inserting an inline extent into
 103  * the btree.  The caller should have done a btrfs_drop_extents so that
 104  * no overlapping inline items exist in the btree
 105  */
 106 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 107                                 struct btrfs_root *root, struct inode *inode,
 108                                 u64 start, size_t size, size_t compressed_size,
 109                                 struct page **compressed_pages)
 110 {
 111         struct btrfs_key key;
 112         struct btrfs_path *path;
 113         struct extent_buffer *leaf;
 114         struct page *page = NULL;
 115         char *kaddr;
 116         unsigned long ptr;
 117         struct btrfs_file_extent_item *ei;
 118         int err = 0;
 119         int ret;
 120         size_t cur_size = size;
 121         size_t datasize;
 122         unsigned long offset;
 123         int use_compress = 0;
 124
 125         if (compressed_size && compressed_pages) {
 126                 use_compress = 1;
 127                 cur_size = compressed_size;
 128         }
 129
 130         path = btrfs_alloc_path();
 131         if (!path)
 132                 return -ENOMEM;
 133
 134         path->leave_spinning = 1;
 135         btrfs_set_trans_block_group(trans, inode);
 136
 137         key.objectid = inode->i_ino;
 138         key.offset = start;
 139         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 140         datasize = btrfs_file_extent_calc_inline_size(cur_size);
 141
 142         inode_add_bytes(inode, size);
 143         ret = btrfs_insert_empty_item(trans, root, path, &key,
 144                                       datasize);
 145         BUG_ON(ret);
 146         if (ret) {
 147                 err = ret;
 148                 goto fail;
 149         }
 150         leaf = path->nodes[0];
 151         ei = btrfs_item_ptr(leaf, path->slots[0],
 152                             struct btrfs_file_extent_item);
 153         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 154         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 155         btrfs_set_file_extent_encryption(leaf, ei, 0);
 156         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 157         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 158         ptr = btrfs_file_extent_inline_start(ei);
 159
 160         if (use_compress) {
 161                 struct page *cpage;
 162                 int i = 0;
 163                 while (compressed_size > 0) {
 164                         cpage = compressed_pages[i];
 165                         cur_size = min_t(unsigned long, compressed_size,
 166                                        PAGE_CACHE_SIZE);
 167
 168                         kaddr = kmap_atomic(cpage, KM_USER0);
 169                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 170                         kunmap_atomic(kaddr, KM_USER0);
 171
 172                         i++;
 173                         ptr += cur_size;
 174                         compressed_size -= cur_size;
 175                 }
 176                 btrfs_set_file_extent_compression(leaf, ei,
 177                                                   BTRFS_COMPRESS_ZLIB);
 178         } else {
 179                 page = find_get_page(inode->i_mapping,
 180                                      start >> PAGE_CACHE_SHIFT);
 181                 btrfs_set_file_extent_compression(leaf, ei, 0);
 182                 kaddr = kmap_atomic(page, KM_USER0);
 183                 offset = start & (PAGE_CACHE_SIZE - 1);
 184                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 185                 kunmap_atomic(kaddr, KM_USER0);
 186                 page_cache_release(page);
 187         }
 188         btrfs_mark_buffer_dirty(leaf);
 189         btrfs_free_path(path);
 190
 191         BTRFS_I(inode)->disk_i_size = inode->i_size;
 192         btrfs_update_inode(trans, root, inode);
 193         return 0;
 194 fail:
 195         btrfs_free_path(path);
 196         return err;
 197 }
 198
 199
 200 /*
 201  * conditionally insert an inline extent into the file.  This
 202  * does the checks required to make sure the data is small enough
 203  * to fit as an inline extent.
 204  */
 205 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
 206                                  struct btrfs_root *root,
 207                                  struct inode *inode, u64 start, u64 end,
 208                                  size_t compressed_size,
 209                                  struct page **compressed_pages)
 210 {
 211         u64 isize = i_size_read(inode);
 212         u64 actual_end = min(end + 1, isize);
 213         u64 inline_len = actual_end - start;
 214         u64 aligned_end = (end + root->sectorsize - 1) &
 215                         ~((u64)root->sectorsize - 1);
 216         u64 hint_byte;
 217         u64 data_len = inline_len;
 218         int ret;
 219
 220         if (compressed_size)
 221                 data_len = compressed_size;
 222
 223         if (start > 0 ||
 224             actual_end >= PAGE_CACHE_SIZE ||
 225             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 226             (!compressed_size &&
 227             (actual_end & (root->sectorsize - 1)) == 0) ||
 228             end + 1 < isize ||
 229             data_len > root->fs_info->max_inline) {
 230                 return 1;
 231         }
 232
 233         ret = btrfs_drop_extents(trans, root, inode, start,
 234                                  aligned_end, aligned_end, start,
 235                                  &hint_byte, 1);
 236         BUG_ON(ret);
 237
 238         if (isize > actual_end)
 239                 inline_len = min_t(u64, isize, actual_end);
 240         ret = insert_inline_extent(trans, root, inode, start,
 241                                    inline_len, compressed_size,
 242                                    compressed_pages);
 243         BUG_ON(ret);
 244         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 245         return 0;
 246 }
 247
 248 struct async_extent {
 249         u64 start;
 250         u64 ram_size;
 251         u64 compressed_size;
 252         struct page **pages;
 253         unsigned long nr_pages;
 254         struct list_head list;
 255 };
 256
 257 struct async_cow {
 258         struct inode *inode;
 259         struct btrfs_root *root;
 260         struct page *locked_page;
 261         u64 start;
 262         u64 end;
 263         struct list_head extents;
 264         struct btrfs_work work;
 265 };
 266
 267 static noinline int add_async_extent(struct async_cow *cow,
 268                                      u64 start, u64 ram_size,
 269                                      u64 compressed_size,
 270                                      struct page **pages,
 271                                      unsigned long nr_pages)
 272 {
 273         struct async_extent *async_extent;
 274
 275         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 276         async_extent->start = start;
 277         async_extent->ram_size = ram_size;
 278         async_extent->compressed_size = compressed_size;
 279         async_extent->pages = pages;
 280         async_extent->nr_pages = nr_pages;
 281         list_add_tail(&async_extent->list, &cow->extents);
 282         return 0;
 283 }
 284
 285 /*
 286  * we create compressed extents in two phases.  The first
 287  * phase compresses a range of pages that have already been
 288  * locked (both pages and state bits are locked).
 289  *
 290  * This is done inside an ordered work queue, and the compression
 291  * is spread across many cpus.  The actual IO submission is step
 292  * two, and the ordered work queue takes care of making sure that
 293  * happens in the same order things were put onto the queue by
 294  * writepages and friends.
 295  *
 296  * If this code finds it can't get good compression, it puts an
 297  * entry onto the work queue to write the uncompressed bytes.  This
 298  * makes sure that both compressed inodes and uncompressed inodes
 299  * are written in the same order that pdflush sent them down.
 300  */
 301 static noinline int compress_file_range(struct inode *inode,
 302                                         struct page *locked_page,
 303                                         u64 start, u64 end,
 304                                         struct async_cow *async_cow,
 305                                         int *num_added)
 306 {
 307         struct btrfs_root *root = BTRFS_I(inode)->root;
 308         struct btrfs_trans_handle *trans;
 309         u64 num_bytes;
 310         u64 orig_start;
 311         u64 disk_num_bytes;
 312         u64 blocksize = root->sectorsize;
 313         u64 actual_end;
 314         u64 isize = i_size_read(inode);
 315         int ret = 0;
 316         struct page **pages = NULL;
 317         unsigned long nr_pages;
 318         unsigned long nr_pages_ret = 0;
 319         unsigned long total_compressed = 0;
 320         unsigned long total_in = 0;
 321         unsigned long max_compressed = 128 * 1024;
 322         unsigned long max_uncompressed = 128 * 1024;
 323         int i;
 324         int will_compress;
 325
 326         orig_start = start;
 327
 328         actual_end = min_t(u64, isize, end + 1);
 329 again:
 330         will_compress = 0;
 331         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 332         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 333
 334         /*
 335          * we don't want to send crud past the end of i_size through
 336          * compression, that's just a waste of CPU time.  So, if the
 337          * end of the file is before the start of our current
 338          * requested range of bytes, we bail out to the uncompressed
 339          * cleanup code that can deal with all of this.
 340          *
 341          * It isn't really the fastest way to fix things, but this is a
 342          * very uncommon corner.
 343          */
 344         if (actual_end <= start)
 345                 goto cleanup_and_bail_uncompressed;
 346
 347         total_compressed = actual_end - start;
 348
 349         /* we want to make sure that amount of ram required to uncompress
 350          * an extent is reasonable, so we limit the total size in ram
 351          * of a compressed extent to 128k.  This is a crucial number
 352          * because it also controls how easily we can spread reads across
 353          * cpus for decompression.
 354          *
 355          * We also want to make sure the amount of IO required to do
 356          * a random read is reasonably small, so we limit the size of
 357          * a compressed extent to 128k.
 358          */
 359         total_compressed = min(total_compressed, max_uncompressed);
 360         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 361         num_bytes = max(blocksize,  num_bytes);
 362         disk_num_bytes = num_bytes;
 363         total_in = 0;
 364         ret = 0;
 365
 366         /*
 367          * we do compression for mount -o compress and when the
 368          * inode has not been flagged as nocompress.  This flag can
 369          * change at any time if we discover bad compression ratios.
 370          */
 371         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 372             btrfs_test_opt(root, COMPRESS)) {
 373                 WARN_ON(pages);
 374                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 375
 376                 ret = btrfs_zlib_compress_pages(inode->i_mapping, start,
 377                                                 total_compressed, pages,
 378                                                 nr_pages, &nr_pages_ret,
 379                                                 &total_in,
 380                                                 &total_compressed,
 381                                                 max_compressed);
 382
 383                 if (!ret) {
 384                         unsigned long offset = total_compressed &
 385                                 (PAGE_CACHE_SIZE - 1);
 386                         struct page *page = pages[nr_pages_ret - 1];
 387                         char *kaddr;
 388
 389                         /* zero the tail end of the last page, we might be
 390                          * sending it down to disk
 391                          */
 392                         if (offset) {
 393                                 kaddr = kmap_atomic(page, KM_USER0);
 394                                 memset(kaddr + offset, 0,
 395                                        PAGE_CACHE_SIZE - offset);
 396                                 kunmap_atomic(kaddr, KM_USER0);
 397                         }
 398                         will_compress = 1;
 399                 }
 400         }
 401         if (start == 0) {
 402                 trans = btrfs_join_transaction(root, 1);
 403                 BUG_ON(!trans);
 404                 btrfs_set_trans_block_group(trans, inode);
 405
 406                 /* lets try to make an inline extent */
 407                 if (ret || total_in < (actual_end - start)) {
 408                         /* we didn't compress the entire range, try
 409                          * to make an uncompressed inline extent.
 410                          */
 411                         ret = cow_file_range_inline(trans, root, inode,
 412                                                     start, end, 0, NULL);
 413                 } else {
 414                         /* try making a compressed inline extent */
 415                         ret = cow_file_range_inline(trans, root, inode,
 416                                                     start, end,
 417                                                     total_compressed, pages);
 418                 }
 419                 btrfs_end_transaction(trans, root);
 420                 if (ret == 0) {
 421                         /*
 422                          * inline extent creation worked, we don't need
 423                          * to create any more async work items.  Unlock
 424                          * and free up our temp pages.
 425                          */
 426                         extent_clear_unlock_delalloc(inode,
 427                                                      &BTRFS_I(inode)->io_tree,
 428                                                      start, end, NULL, 1, 0,
 429                                                      0, 1, 1, 1, 0);
 430                         ret = 0;
 431                         goto free_pages_out;
 432                 }
 433         }
 434
 435         if (will_compress) {
 436                 /*
 437                  * we aren't doing an inline extent round the compressed size
 438                  * up to a block size boundary so the allocator does sane
 439                  * things
 440                  */
 441                 total_compressed = (total_compressed + blocksize - 1) &
 442                         ~(blocksize - 1);
 443
 444                 /*
 445                  * one last check to make sure the compression is really a
 446                  * win, compare the page count read with the blocks on disk
 447                  */
 448                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
 449                         ~(PAGE_CACHE_SIZE - 1);
 450                 if (total_compressed >= total_in) {
 451                         will_compress = 0;
 452                 } else {
 453                         disk_num_bytes = total_compressed;
 454                         num_bytes = total_in;
 455                 }
 456         }
 457         if (!will_compress && pages) {
 458                 /*
 459                  * the compression code ran but failed to make things smaller,
 460                  * free any pages it allocated and our page pointer array
 461                  */
 462                 for (i = 0; i < nr_pages_ret; i++) {
 463                         WARN_ON(pages[i]->mapping);
 464                         page_cache_release(pages[i]);
 465                 }
 466                 kfree(pages);
 467                 pages = NULL;
 468                 total_compressed = 0;
 469                 nr_pages_ret = 0;
 470
 471                 /* flag the file so we don't compress in the future */
 472                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 473         }
 474         if (will_compress) {
 475                 *num_added += 1;
 476
 477                 /* the async work queues will take care of doing actual
 478                  * allocation on disk for these compressed pages,
 479                  * and will submit them to the elevator.
 480                  */
 481                 add_async_extent(async_cow, start, num_bytes,
 482                                  total_compressed, pages, nr_pages_ret);
 483
 484                 if (start + num_bytes < end && start + num_bytes < actual_end) {
 485                         start += num_bytes;
 486                         pages = NULL;
 487                         cond_resched();
 488                         goto again;
 489                 }
 490         } else {
 491 cleanup_and_bail_uncompressed:
 492                 /*
 493                  * No compression, but we still need to write the pages in
 494                  * the file we've been given so far.  redirty the locked
 495                  * page if it corresponds to our extent and set things up
 496                  * for the async work queue to run cow_file_range to do
 497                  * the normal delalloc dance
 498                  */
 499                 if (page_offset(locked_page) >= start &&
 500                     page_offset(locked_page) <= end) {
 501                         __set_page_dirty_nobuffers(locked_page);
 502                         /* unlocked later on in the async handlers */
 503                 }
 504                 add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0);
 505                 *num_added += 1;
 506         }
 507
 508 out:
 509         return 0;
 510
 511 free_pages_out:
 512         for (i = 0; i < nr_pages_ret; i++) {
 513                 WARN_ON(pages[i]->mapping);
 514                 page_cache_release(pages[i]);
 515         }
 516         kfree(pages);
 517
 518         goto out;
 519 }
 520
 521 /*
 522  * phase two of compressed writeback.  This is the ordered portion
 523  * of the code, which only gets called in the order the work was
 524  * queued.  We walk all the async extents created by compress_file_range
 525  * and send them down to the disk.
 526  */
 527 static noinline int submit_compressed_extents(struct inode *inode,
 528                                               struct async_cow *async_cow)
 529 {
 530         struct async_extent *async_extent;
 531         u64 alloc_hint = 0;
 532         struct btrfs_trans_handle *trans;
 533         struct btrfs_key ins;
 534         struct extent_map *em;
 535         struct btrfs_root *root = BTRFS_I(inode)->root;
 536         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 537         struct extent_io_tree *io_tree;
 538         int ret;
 539
 540         if (list_empty(&async_cow->extents))
 541                 return 0;
 542
 543         trans = btrfs_join_transaction(root, 1);
 544
 545         while (!list_empty(&async_cow->extents)) {
 546                 async_extent = list_entry(async_cow->extents.next,
 547                                           struct async_extent, list);
 548                 list_del(&async_extent->list);
 549
 550                 io_tree = &BTRFS_I(inode)->io_tree;
 551
 552                 /* did the compression code fall back to uncompressed IO? */
 553                 if (!async_extent->pages) {
 554                         int page_started = 0;
 555                         unsigned long nr_written = 0;
 556
 557                         lock_extent(io_tree, async_extent->start,
 558                                     async_extent->start +
 559                                     async_extent->ram_size - 1, GFP_NOFS);
 560
 561                         /* allocate blocks */
 562                         cow_file_range(inode, async_cow->locked_page,
 563                                        async_extent->start,
 564                                        async_extent->start +
 565                                        async_extent->ram_size - 1,
 566                                        &page_started, &nr_written, 0);
 567
 568                         /*
 569                          * if page_started, cow_file_range inserted an
 570                          * inline extent and took care of all the unlocking
 571                          * and IO for us.  Otherwise, we need to submit
 572                          * all those pages down to the drive.
 573                          */
 574                         if (!page_started)
 575                                 extent_write_locked_range(io_tree,
 576                                                   inode, async_extent->start,
 577                                                   async_extent->start +
 578                                                   async_extent->ram_size - 1,
 579                                                   btrfs_get_extent,
 580                                                   WB_SYNC_ALL);
 581                         kfree(async_extent);
 582                         cond_resched();
 583                         continue;
 584                 }
 585
 586                 lock_extent(io_tree, async_extent->start,
 587                             async_extent->start + async_extent->ram_size - 1,
 588                             GFP_NOFS);
 589                 /*
 590                  * here we're doing allocation and writeback of the
 591                  * compressed pages
 592                  */
 593                 btrfs_drop_extent_cache(inode, async_extent->start,
 594                                         async_extent->start +
 595                                         async_extent->ram_size - 1, 0);
 596
 597                 ret = btrfs_reserve_extent(trans, root,
 598                                            async_extent->compressed_size,
 599                                            async_extent->compressed_size,
 600                                            0, alloc_hint,
 601                                            (u64)-1, &ins, 1);
 602                 BUG_ON(ret);
 603                 em = alloc_extent_map(GFP_NOFS);
 604                 em->start = async_extent->start;
 605                 em->len = async_extent->ram_size;
 606                 em->orig_start = em->start;
 607
 608                 em->block_start = ins.objectid;
 609                 em->block_len = ins.offset;
 610                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 611                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 612                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 613
 614                 while (1) {
 615                         write_lock(&em_tree->lock);
 616                         ret = add_extent_mapping(em_tree, em);
 617                         write_unlock(&em_tree->lock);
 618                         if (ret != -EEXIST) {
 619                                 free_extent_map(em);
 620                                 break;
 621                         }
 622                         btrfs_drop_extent_cache(inode, async_extent->start,
 623                                                 async_extent->start +
 624                                                 async_extent->ram_size - 1, 0);
 625                 }
 626
 627                 ret = btrfs_add_ordered_extent(inode, async_extent->start,
 628                                                ins.objectid,
 629                                                async_extent->ram_size,
 630                                                ins.offset,
 631                                                BTRFS_ORDERED_COMPRESSED);
 632                 BUG_ON(ret);
 633
 634                 btrfs_end_transaction(trans, root);
 635
 636                 /*
 637                  * clear dirty, set writeback and unlock the pages.
 638                  */
 639                 extent_clear_unlock_delalloc(inode,
 640                                              &BTRFS_I(inode)->io_tree,
 641                                              async_extent->start,
 642                                              async_extent->start +
 643                                              async_extent->ram_size - 1,
 644                                              NULL, 1, 1, 0, 1, 1, 0, 0);
 645
 646                 ret = btrfs_submit_compressed_write(inode,
 647                                     async_extent->start,
 648                                     async_extent->ram_size,
 649                                     ins.objectid,
 650                                     ins.offset, async_extent->pages,
 651                                     async_extent->nr_pages);
 652
 653                 BUG_ON(ret);
 654                 trans = btrfs_join_transaction(root, 1);
 655                 alloc_hint = ins.objectid + ins.offset;
 656                 kfree(async_extent);
 657                 cond_resched();
 658         }
 659
 660         btrfs_end_transaction(trans, root);
 661         return 0;
 662 }
 663
 664 /*
 665  * when extent_io.c finds a delayed allocation range in the file,
 666  * the call backs end up in this code.  The basic idea is to
 667  * allocate extents on disk for the range, and create ordered data structs
 668  * in ram to track those extents.
 669  *
 670  * locked_page is the page that writepage had locked already.  We use
 671  * it to make sure we don't do extra locks or unlocks.
 672  *
 673  * *page_started is set to one if we unlock locked_page and do everything
 674  * required to start IO on it.  It may be clean and already done with
 675  * IO when we return.
 676  */
 677 static noinline int cow_file_range(struct inode *inode,
 678                                    struct page *locked_page,
 679                                    u64 start, u64 end, int *page_started,
 680                                    unsigned long *nr_written,
 681                                    int unlock)
 682 {
 683         struct btrfs_root *root = BTRFS_I(inode)->root;
 684         struct btrfs_trans_handle *trans;
 685         u64 alloc_hint = 0;
 686         u64 num_bytes;
 687         unsigned long ram_size;
 688         u64 disk_num_bytes;
 689         u64 cur_alloc_size;
 690         u64 blocksize = root->sectorsize;
 691         u64 actual_end;
 692         u64 isize = i_size_read(inode);
 693         struct btrfs_key ins;
 694         struct extent_map *em;
 695         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 696         int ret = 0;
 697
 698         trans = btrfs_join_transaction(root, 1);
 699         BUG_ON(!trans);
 700         btrfs_set_trans_block_group(trans, inode);
 701
 702         actual_end = min_t(u64, isize, end + 1);
 703
 704         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 705         num_bytes = max(blocksize,  num_bytes);
 706         disk_num_bytes = num_bytes;
 707         ret = 0;
 708
 709         if (start == 0) {
 710                 /* lets try to make an inline extent */
 711                 ret = cow_file_range_inline(trans, root, inode,
 712                                             start, end, 0, NULL);
 713                 if (ret == 0) {
 714                         extent_clear_unlock_delalloc(inode,
 715                                                      &BTRFS_I(inode)->io_tree,
 716                                                      start, end, NULL, 1, 1,
 717                                                      1, 1, 1, 1, 0);
 718                         *nr_written = *nr_written +
 719                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 720                         *page_started = 1;
 721                         ret = 0;
 722                         goto out;
 723                 }
 724         }
 725
 726         BUG_ON(disk_num_bytes >
 727                btrfs_super_total_bytes(&root->fs_info->super_copy));
 728
 729
 730         read_lock(&BTRFS_I(inode)->extent_tree.lock);
 731         em = search_extent_mapping(&BTRFS_I(inode)->extent_tree,
 732                                    start, num_bytes);
 733         if (em) {
 734                 alloc_hint = em->block_start;
 735                 free_extent_map(em);
 736         }
 737         read_unlock(&BTRFS_I(inode)->extent_tree.lock);
 738         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 739
 740         while (disk_num_bytes > 0) {
 741                 cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
 742                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
 743                                            root->sectorsize, 0, alloc_hint,
 744                                            (u64)-1, &ins, 1);
 745                 BUG_ON(ret);
 746
 747                 em = alloc_extent_map(GFP_NOFS);
 748                 em->start = start;
 749                 em->orig_start = em->start;
 750                 ram_size = ins.offset;
 751                 em->len = ins.offset;
 752
 753                 em->block_start = ins.objectid;
 754                 em->block_len = ins.offset;
 755                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 756                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 757
 758                 while (1) {
 759                         write_lock(&em_tree->lock);
 760                         ret = add_extent_mapping(em_tree, em);
 761                         write_unlock(&em_tree->lock);
 762                         if (ret != -EEXIST) {
 763                                 free_extent_map(em);
 764                                 break;
 765                         }
 766                         btrfs_drop_extent_cache(inode, start,
 767                                                 start + ram_size - 1, 0);
 768                 }
 769
 770                 cur_alloc_size = ins.offset;
 771                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 772                                                ram_size, cur_alloc_size, 0);
 773                 BUG_ON(ret);
 774
 775                 if (root->root_key.objectid ==
 776                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 777                         ret = btrfs_reloc_clone_csums(inode, start,
 778                                                       cur_alloc_size);
 779                         BUG_ON(ret);
 780                 }
 781
 782                 if (disk_num_bytes < cur_alloc_size)
 783                         break;
 784
 785                 /* we're not doing compressed IO, don't unlock the first
 786                  * page (which the caller expects to stay locked), don't
 787                  * clear any dirty bits and don't set any writeback bits
 788                  *
 789                  * Do set the Private2 bit so we know this page was properly
 790                  * setup for writepage
 791                  */
 792                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
 793                                              start, start + ram_size - 1,
 794                                              locked_page, unlock, 1,
 795                                              1, 0, 0, 0, 1);
 796                 disk_num_bytes -= cur_alloc_size;
 797                 num_bytes -= cur_alloc_size;
 798                 alloc_hint = ins.objectid + ins.offset;
 799                 start += cur_alloc_size;
 800         }
 801 out:
 802         ret = 0;
 803         btrfs_end_transaction(trans, root);
 804
 805         return ret;
 806 }
 807
 808 /*
 809  * work queue call back to started compression on a file and pages
 810  */
 811 static noinline void async_cow_start(struct btrfs_work *work)
 812 {
 813         struct async_cow *async_cow;
 814         int num_added = 0;
 815         async_cow = container_of(work, struct async_cow, work);
 816
 817         compress_file_range(async_cow->inode, async_cow->locked_page,
 818                             async_cow->start, async_cow->end, async_cow,
 819                             &num_added);
 820         if (num_added == 0)
 821                 async_cow->inode = NULL;
 822 }
 823
 824 /*
 825  * work queue call back to submit previously compressed pages
 826  */
 827 static noinline void async_cow_submit(struct btrfs_work *work)
 828 {
 829         struct async_cow *async_cow;
 830         struct btrfs_root *root;
 831         unsigned long nr_pages;
 832
 833         async_cow = container_of(work, struct async_cow, work);
 834
 835         root = async_cow->root;
 836         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
 837                 PAGE_CACHE_SHIFT;
 838
 839         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
 840
 841         if (atomic_read(&root->fs_info->async_delalloc_pages) <
 842             5 * 1042 * 1024 &&
 843             waitqueue_active(&root->fs_info->async_submit_wait))
 844                 wake_up(&root->fs_info->async_submit_wait);
 845
 846         if (async_cow->inode)
 847                 submit_compressed_extents(async_cow->inode, async_cow);
 848 }
 849
 850 static noinline void async_cow_free(struct btrfs_work *work)
 851 {
 852         struct async_cow *async_cow;
 853         async_cow = container_of(work, struct async_cow, work);
 854         kfree(async_cow);
 855 }
 856
 857 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
 858                                 u64 start, u64 end, int *page_started,
 859                                 unsigned long *nr_written)
 860 {
 861         struct async_cow *async_cow;
 862         struct btrfs_root *root = BTRFS_I(inode)->root;
 863         unsigned long nr_pages;
 864         u64 cur_end;
 865         int limit = 10 * 1024 * 1042;
 866
 867         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED |
 868                          EXTENT_DELALLOC, 1, 0, NULL, GFP_NOFS);
 869         while (start < end) {
 870                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
 871                 async_cow->inode = inode;
 872                 async_cow->root = root;
 873                 async_cow->locked_page = locked_page;
 874                 async_cow->start = start;
 875
 876                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 877                         cur_end = end;
 878                 else
 879                         cur_end = min(end, start + 512 * 1024 - 1);
 880
 881                 async_cow->end = cur_end;
 882                 INIT_LIST_HEAD(&async_cow->extents);
 883
 884                 async_cow->work.func = async_cow_start;
 885                 async_cow->work.ordered_func = async_cow_submit;
 886                 async_cow->work.ordered_free = async_cow_free;
 887                 async_cow->work.flags = 0;
 888
 889                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
 890                         PAGE_CACHE_SHIFT;
 891                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
 892
 893                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
 894                                    &async_cow->work);
 895
 896                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
 897                         wait_event(root->fs_info->async_submit_wait,
 898                            (atomic_read(&root->fs_info->async_delalloc_pages) <
 899                             limit));
 900                 }
 901
 902                 while (atomic_read(&root->fs_info->async_submit_draining) &&
 903                       atomic_read(&root->fs_info->async_delalloc_pages)) {
 904                         wait_event(root->fs_info->async_submit_wait,
 905                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
 906                            0));
 907                 }
 908
 909                 *nr_written += nr_pages;
 910                 start = cur_end + 1;
 911         }
 912         *page_started = 1;
 913         return 0;
 914 }
 915
 916 static noinline int csum_exist_in_range(struct btrfs_root *root,
 917                                         u64 bytenr, u64 num_bytes)
 918 {
 919         int ret;
 920         struct btrfs_ordered_sum *sums;
 921         LIST_HEAD(list);
 922
 923         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
 924                                        bytenr + num_bytes - 1, &list);
 925         if (ret == 0 && list_empty(&list))
 926                 return 0;
 927
 928         while (!list_empty(&list)) {
 929                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
 930                 list_del(&sums->list);
 931                 kfree(sums);
 932         }
 933         return 1;
 934 }
 935
 936 /*
 937  * when nowcow writeback call back.  This checks for snapshots or COW copies
 938  * of the extents that exist in the file, and COWs the file as required.
 939  *
 940  * If no cow copies or snapshots exist, we write directly to the existing
 941  * blocks on disk
 942  */
 943 static noinline int run_delalloc_nocow(struct inode *inode,
 944                                        struct page *locked_page,
 945                               u64 start, u64 end, int *page_started, int force,
 946                               unsigned long *nr_written)
 947 {
 948         struct btrfs_root *root = BTRFS_I(inode)->root;
 949         struct btrfs_trans_handle *trans;
 950         struct extent_buffer *leaf;
 951         struct btrfs_path *path;
 952         struct btrfs_file_extent_item *fi;
 953         struct btrfs_key found_key;
 954         u64 cow_start;
 955         u64 cur_offset;
 956         u64 extent_end;
 957         u64 extent_offset;
 958         u64 disk_bytenr;
 959         u64 num_bytes;
 960         int extent_type;
 961         int ret;
 962         int type;
 963         int nocow;
 964         int check_prev = 1;
 965
 966         path = btrfs_alloc_path();
 967         BUG_ON(!path);
 968         trans = btrfs_join_transaction(root, 1);
 969         BUG_ON(!trans);
 970
 971         cow_start = (u64)-1;
 972         cur_offset = start;
 973         while (1) {
 974                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 975                                                cur_offset, 0);
 976                 BUG_ON(ret < 0);
 977                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
 978                         leaf = path->nodes[0];
 979                         btrfs_item_key_to_cpu(leaf, &found_key,
 980                                               path->slots[0] - 1);
 981                         if (found_key.objectid == inode->i_ino &&
 982                             found_key.type == BTRFS_EXTENT_DATA_KEY)
 983                                 path->slots[0]--;
 984                 }
 985                 check_prev = 0;
 986 next_slot:
 987                 leaf = path->nodes[0];
 988                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 989                         ret = btrfs_next_leaf(root, path);
 990                         if (ret < 0)
 991                                 BUG_ON(1);
 992                         if (ret > 0)
 993                                 break;
 994                         leaf = path->nodes[0];
 995                 }
 996
 997                 nocow = 0;
 998                 disk_bytenr = 0;
 999                 num_bytes = 0;
1000                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1001
1002                 if (found_key.objectid > inode->i_ino ||
1003                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1004                     found_key.offset > end)
1005                         break;
1006
1007                 if (found_key.offset > cur_offset) {
1008                         extent_end = found_key.offset;
1009                         goto out_check;
1010                 }
1011
1012                 fi = btrfs_item_ptr(leaf, path->slots[0],
1013                                     struct btrfs_file_extent_item);
1014                 extent_type = btrfs_file_extent_type(leaf, fi);
1015
1016                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1017                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1018                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1019                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1020                         extent_end = found_key.offset +
1021                                 btrfs_file_extent_num_bytes(leaf, fi);
1022                         if (extent_end <= start) {
1023                                 path->slots[0]++;
1024                                 goto next_slot;
1025                         }
1026                         if (disk_bytenr == 0)
1027                                 goto out_check;
1028                         if (btrfs_file_extent_compression(leaf, fi) ||
1029                             btrfs_file_extent_encryption(leaf, fi) ||
1030                             btrfs_file_extent_other_encoding(leaf, fi))
1031                                 goto out_check;
1032                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1033                                 goto out_check;
1034                         if (btrfs_extent_readonly(root, disk_bytenr))
1035                                 goto out_check;
1036                         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
1037                                                   found_key.offset -
1038                                                   extent_offset, disk_bytenr))
1039                                 goto out_check;
1040                         disk_bytenr += extent_offset;
1041                         disk_bytenr += cur_offset - found_key.offset;
1042                         num_bytes = min(end + 1, extent_end) - cur_offset;
1043                         /*
1044                          * force cow if csum exists in the range.
1045                          * this ensure that csum for a given extent are
1046                          * either valid or do not exist.
1047                          */
1048                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1049                                 goto out_check;
1050                         nocow = 1;
1051                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1052                         extent_end = found_key.offset +
1053                                 btrfs_file_extent_inline_len(leaf, fi);
1054                         extent_end = ALIGN(extent_end, root->sectorsize);
1055                 } else {
1056                         BUG_ON(1);
1057                 }
1058 out_check:
1059                 if (extent_end <= start) {
1060                         path->slots[0]++;
1061                         goto next_slot;
1062                 }
1063                 if (!nocow) {
1064                         if (cow_start == (u64)-1)
1065                                 cow_start = cur_offset;
1066                         cur_offset = extent_end;
1067                         if (cur_offset > end)
1068                                 break;
1069                         path->slots[0]++;
1070                         goto next_slot;
1071                 }
1072
1073                 btrfs_release_path(root, path);
1074                 if (cow_start != (u64)-1) {
1075                         ret = cow_file_range(inode, locked_page, cow_start,
1076                                         found_key.offset - 1, page_started,
1077                                         nr_written, 1);
1078                         BUG_ON(ret);
1079                         cow_start = (u64)-1;
1080                 }
1081
1082                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1083                         struct extent_map *em;
1084                         struct extent_map_tree *em_tree;
1085                         em_tree = &BTRFS_I(inode)->extent_tree;
1086                         em = alloc_extent_map(GFP_NOFS);
1087                         em->start = cur_offset;
1088                         em->orig_start = em->start;
1089                         em->len = num_bytes;
1090                         em->block_len = num_bytes;
1091                         em->block_start = disk_bytenr;
1092                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1093                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1094                         while (1) {
1095                                 write_lock(&em_tree->lock);
1096                                 ret = add_extent_mapping(em_tree, em);
1097                                 write_unlock(&em_tree->lock);
1098                                 if (ret != -EEXIST) {
1099                                         free_extent_map(em);
1100                                         break;
1101                                 }
1102                                 btrfs_drop_extent_cache(inode, em->start,
1103                                                 em->start + em->len - 1, 0);
1104                         }
1105                         type = BTRFS_ORDERED_PREALLOC;
1106                 } else {
1107                         type = BTRFS_ORDERED_NOCOW;
1108                 }
1109
1110                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1111                                                num_bytes, num_bytes, type);
1112                 BUG_ON(ret);
1113
1114                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1115                                         cur_offset, cur_offset + num_bytes - 1,
1116                                         locked_page, 1, 1, 1, 0, 0, 0, 1);
1117                 cur_offset = extent_end;
1118                 if (cur_offset > end)
1119                         break;
1120         }
1121         btrfs_release_path(root, path);
1122
1123         if (cur_offset <= end && cow_start == (u64)-1)
1124                 cow_start = cur_offset;
1125         if (cow_start != (u64)-1) {
1126                 ret = cow_file_range(inode, locked_page, cow_start, end,
1127                                      page_started, nr_written, 1);
1128                 BUG_ON(ret);
1129         }
1130
1131         ret = btrfs_end_transaction(trans, root);
1132         BUG_ON(ret);
1133         btrfs_free_path(path);
1134         return 0;
1135 }
1136
1137 /*
1138  * extent_io.c call back to do delayed allocation processing
1139  */
1140 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1141                               u64 start, u64 end, int *page_started,
1142                               unsigned long *nr_written)
1143 {
1144         int ret;
1145         struct btrfs_root *root = BTRFS_I(inode)->root;
1146
1147         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1148                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1149                                          page_started, 1, nr_written);
1150         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1151                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1152                                          page_started, 0, nr_written);
1153         else if (!btrfs_test_opt(root, COMPRESS))
1154                 ret = cow_file_range(inode, locked_page, start, end,
1155                                       page_started, nr_written, 1);
1156         else
1157                 ret = cow_file_range_async(inode, locked_page, start, end,
1158                                            page_started, nr_written);
1159         return ret;
1160 }
1161
1162 static int btrfs_split_extent_hook(struct inode *inode,
1163                                     struct extent_state *orig, u64 split)
1164 {
1165         struct btrfs_root *root = BTRFS_I(inode)->root;
1166         u64 size;
1167
1168         if (!(orig->state & EXTENT_DELALLOC))
1169                 return 0;
1170
1171         size = orig->end - orig->start + 1;
1172         if (size > root->fs_info->max_extent) {
1173                 u64 num_extents;
1174                 u64 new_size;
1175
1176                 new_size = orig->end - split + 1;
1177                 num_extents = div64_u64(size + root->fs_info->max_extent - 1,
1178                                         root->fs_info->max_extent);
1179
1180                 /*
1181                  * if we break a large extent up then leave delalloc_extents be,
1182                  * since we've already accounted for the large extent.
1183                  */
1184                 if (div64_u64(new_size + root->fs_info->max_extent - 1,
1185                               root->fs_info->max_extent) < num_extents)
1186                         return 0;
1187         }
1188
1189         BTRFS_I(inode)->delalloc_extents++;
1190
1191         return 0;
1192 }
1193
1194 /*
1195  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1196  * extents so we can keep track of new extents that are just merged onto old
1197  * extents, such as when we are doing sequential writes, so we can properly
1198  * account for the metadata space we'll need.
1199  */
1200 static int btrfs_merge_extent_hook(struct inode *inode,
1201                                    struct extent_state *new,
1202                                    struct extent_state *other)
1203 {
1204         struct btrfs_root *root = BTRFS_I(inode)->root;
1205         u64 new_size, old_size;
1206         u64 num_extents;
1207
1208         /* not delalloc, ignore it */
1209         if (!(other->state & EXTENT_DELALLOC))
1210                 return 0;
1211
1212         old_size = other->end - other->start + 1;
1213         if (new->start < other->start)
1214                 new_size = other->end - new->start + 1;
1215         else
1216                 new_size = new->end - other->start + 1;
1217
1218         /* we're not bigger than the max, unreserve the space and go */
1219         if (new_size <= root->fs_info->max_extent) {
1220                 BTRFS_I(inode)->delalloc_extents--;
1221                 return 0;
1222         }
1223
1224         /*
1225          * If we grew by another max_extent, just return, we want to keep that
1226          * reserved amount.
1227          */
1228         num_extents = div64_u64(old_size + root->fs_info->max_extent - 1,
1229                                 root->fs_info->max_extent);
1230         if (div64_u64(new_size + root->fs_info->max_extent - 1,
1231                       root->fs_info->max_extent) > num_extents)
1232                 return 0;
1233
1234         BTRFS_I(inode)->delalloc_extents--;
1235
1236         return 0;
1237 }
1238
1239 /*
1240  * extent_io.c set_bit_hook, used to track delayed allocation
1241  * bytes in this file, and to maintain the list of inodes that
1242  * have pending delalloc work to be done.
1243  */
1244 static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
1245                        unsigned long old, unsigned long bits)
1246 {
1247
1248         /*
1249          * set_bit and clear bit hooks normally require _irqsave/restore
1250          * but in this case, we are only testeing for the DELALLOC
1251          * bit, which is only set or cleared with irqs on
1252          */
1253         if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
1254                 struct btrfs_root *root = BTRFS_I(inode)->root;
1255
1256                 BTRFS_I(inode)->delalloc_extents++;
1257                 btrfs_delalloc_reserve_space(root, inode, end - start + 1);
1258                 spin_lock(&root->fs_info->delalloc_lock);
1259                 BTRFS_I(inode)->delalloc_bytes += end - start + 1;
1260                 root->fs_info->delalloc_bytes += end - start + 1;
1261                 if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1262                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1263                                       &root->fs_info->delalloc_inodes);
1264                 }
1265                 spin_unlock(&root->fs_info->delalloc_lock);
1266         }
1267         return 0;
1268 }
1269
1270 /*
1271  * extent_io.c clear_bit_hook, see set_bit_hook for why
1272  */
1273 static int btrfs_clear_bit_hook(struct inode *inode,
1274                                 struct extent_state *state, unsigned long bits)
1275 {
1276         /*
1277          * set_bit and clear bit hooks normally require _irqsave/restore
1278          * but in this case, we are only testeing for the DELALLOC
1279          * bit, which is only set or cleared with irqs on
1280          */
1281         if ((state->state & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
1282                 struct btrfs_root *root = BTRFS_I(inode)->root;
1283
1284                 BTRFS_I(inode)->delalloc_extents--;
1285                 btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
1286
1287                 spin_lock(&root->fs_info->delalloc_lock);
1288                 if (state->end - state->start + 1 >
1289                     root->fs_info->delalloc_bytes) {
1290                         printk(KERN_INFO "btrfs warning: delalloc account "
1291                                "%llu %llu\n",
1292                                (unsigned long long)
1293                                state->end - state->start + 1,
1294                                (unsigned long long)
1295                                root->fs_info->delalloc_bytes);
1296                         btrfs_delalloc_free_space(root, inode, (u64)-1);
1297                         root->fs_info->delalloc_bytes = 0;
1298                         BTRFS_I(inode)->delalloc_bytes = 0;
1299                 } else {
1300                         btrfs_delalloc_free_space(root, inode,
1301                                                   state->end -
1302                                                   state->start + 1);
1303                         root->fs_info->delalloc_bytes -= state->end -
1304                                 state->start + 1;
1305                         BTRFS_I(inode)->delalloc_bytes -= state->end -
1306                                 state->start + 1;
1307                 }
1308                 if (BTRFS_I(inode)->delalloc_bytes == 0 &&
1309                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1310                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1311                 }
1312                 spin_unlock(&root->fs_info->delalloc_lock);
1313         }
1314         return 0;
1315 }
1316
1317 /*
1318  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1319  * we don't create bios that span stripes or chunks
1320  */
1321 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1322                          size_t size, struct bio *bio,
1323                          unsigned long bio_flags)
1324 {
1325         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1326         struct btrfs_mapping_tree *map_tree;
1327         u64 logical = (u64)bio->bi_sector << 9;
1328         u64 length = 0;
1329         u64 map_length;
1330         int ret;
1331
1332         if (bio_flags & EXTENT_BIO_COMPRESSED)
1333                 return 0;
1334
1335         length = bio->bi_size;
1336         map_tree = &root->fs_info->mapping_tree;
1337         map_length = length;
1338         ret = btrfs_map_block(map_tree, READ, logical,
1339                               &map_length, NULL, 0);
1340
1341         if (map_length < length + size)
1342                 return 1;
1343         return 0;
1344 }
1345
1346 /*
1347  * in order to insert checksums into the metadata in large chunks,
1348  * we wait until bio submission time.   All the pages in the bio are
1349  * checksummed and sums are attached onto the ordered extent record.
1350  *
1351  * At IO completion time the cums attached on the ordered extent record
1352  * are inserted into the btree
1353  */
1354 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1355                                     struct bio *bio, int mirror_num,
1356                                     unsigned long bio_flags)
1357 {
1358         struct btrfs_root *root = BTRFS_I(inode)->root;
1359         int ret = 0;
1360
1361         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1362         BUG_ON(ret);
1363         return 0;
1364 }
1365
1366 /*
1367  * in order to insert checksums into the metadata in large chunks,
1368  * we wait until bio submission time.   All the pages in the bio are
1369  * checksummed and sums are attached onto the ordered extent record.
1370  *
1371  * At IO completion time the cums attached on the ordered extent record
1372  * are inserted into the btree
1373  */
1374 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1375                           int mirror_num, unsigned long bio_flags)
1376 {
1377         struct btrfs_root *root = BTRFS_I(inode)->root;
1378         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1379 }
1380
1381 /*
1382  * extent_io.c submission hook. This does the right thing for csum calculation
1383  * on write, or reading the csums from the tree before a read
1384  */
1385 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1386                           int mirror_num, unsigned long bio_flags)
1387 {
1388         struct btrfs_root *root = BTRFS_I(inode)->root;
1389         int ret = 0;
1390         int skip_sum;
1391
1392         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1393
1394         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1395         BUG_ON(ret);
1396
1397         if (!(rw & (1 << BIO_RW))) {
1398                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1399                         return btrfs_submit_compressed_read(inode, bio,
1400                                                     mirror_num, bio_flags);
1401                 } else if (!skip_sum)
1402                         btrfs_lookup_bio_sums(root, inode, bio, NULL);
1403                 goto mapit;
1404         } else if (!skip_sum) {
1405                 /* csum items have already been cloned */
1406                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1407                         goto mapit;
1408                 /* we're doing a write, do the async checksumming */
1409                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1410                                    inode, rw, bio, mirror_num,
1411                                    bio_flags, __btrfs_submit_bio_start,
1412                                    __btrfs_submit_bio_done);
1413         }
1414
1415 mapit:
1416         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1417 }
1418
1419 /*
1420  * given a list of ordered sums record them in the inode.  This happens
1421  * at IO completion time based on sums calculated at bio submission time.
1422  */
1423 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1424                              struct inode *inode, u64 file_offset,
1425                              struct list_head *list)
1426 {
1427         struct btrfs_ordered_sum *sum;
1428
1429         btrfs_set_trans_block_group(trans, inode);
1430
1431         list_for_each_entry(sum, list, list) {
1432                 btrfs_csum_file_blocks(trans,
1433                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1434         }
1435         return 0;
1436 }
1437
1438 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end)
1439 {
1440         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1441                 WARN_ON(1);
1442         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1443                                    GFP_NOFS);
1444 }
1445
1446 /* see btrfs_writepage_start_hook for details on why this is required */
1447 struct btrfs_writepage_fixup {
1448         struct page *page;
1449         struct btrfs_work work;
1450 };
1451
1452 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1453 {
1454         struct btrfs_writepage_fixup *fixup;
1455         struct btrfs_ordered_extent *ordered;
1456         struct page *page;
1457         struct inode *inode;
1458         u64 page_start;
1459         u64 page_end;
1460
1461         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1462         page = fixup->page;
1463 again:
1464         lock_page(page);
1465         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1466                 ClearPageChecked(page);
1467                 goto out_page;
1468         }
1469
1470         inode = page->mapping->host;
1471         page_start = page_offset(page);
1472         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1473
1474         lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
1475
1476         /* already ordered? We're done */
1477         if (PagePrivate2(page))
1478                 goto out;
1479
1480         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1481         if (ordered) {
1482                 unlock_extent(&BTRFS_I(inode)->io_tree, page_start,
1483                               page_end, GFP_NOFS);
1484                 unlock_page(page);
1485                 btrfs_start_ordered_extent(inode, ordered, 1);
1486                 goto again;
1487         }
1488
1489         btrfs_set_extent_delalloc(inode, page_start, page_end);
1490         ClearPageChecked(page);
1491 out:
1492         unlock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
1493 out_page:
1494         unlock_page(page);
1495         page_cache_release(page);
1496 }
1497
1498 /*
1499  * There are a few paths in the higher layers of the kernel that directly
1500  * set the page dirty bit without asking the filesystem if it is a
1501  * good idea.  This causes problems because we want to make sure COW
1502  * properly happens and the data=ordered rules are followed.
1503  *
1504  * In our case any range that doesn't have the ORDERED bit set
1505  * hasn't been properly setup for IO.  We kick off an async process
1506  * to fix it up.  The async helper will wait for ordered extents, set
1507  * the delalloc bit and make it safe to write the page.
1508  */
1509 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1510 {
1511         struct inode *inode = page->mapping->host;
1512         struct btrfs_writepage_fixup *fixup;
1513         struct btrfs_root *root = BTRFS_I(inode)->root;
1514
1515         /* this page is properly in the ordered list */
1516         if (TestClearPagePrivate2(page))
1517                 return 0;
1518
1519         if (PageChecked(page))
1520                 return -EAGAIN;
1521
1522         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1523         if (!fixup)
1524                 return -EAGAIN;
1525
1526         SetPageChecked(page);
1527         page_cache_get(page);
1528         fixup->work.func = btrfs_writepage_fixup_worker;
1529         fixup->page = page;
1530         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1531         return -EAGAIN;
1532 }
1533
1534 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1535                                        struct inode *inode, u64 file_pos,
1536                                        u64 disk_bytenr, u64 disk_num_bytes,
1537                                        u64 num_bytes, u64 ram_bytes,
1538                                        u64 locked_end,
1539                                        u8 compression, u8 encryption,
1540                                        u16 other_encoding, int extent_type)
1541 {
1542         struct btrfs_root *root = BTRFS_I(inode)->root;
1543         struct btrfs_file_extent_item *fi;
1544         struct btrfs_path *path;
1545         struct extent_buffer *leaf;
1546         struct btrfs_key ins;
1547         u64 hint;
1548         int ret;
1549
1550         path = btrfs_alloc_path();
1551         BUG_ON(!path);
1552
1553         path->leave_spinning = 1;
1554
1555         /*
1556          * we may be replacing one extent in the tree with another.
1557          * The new extent is pinned in the extent map, and we don't want
1558          * to drop it from the cache until it is completely in the btree.
1559          *
1560          * So, tell btrfs_drop_extents to leave this extent in the cache.
1561          * the caller is expected to unpin it and allow it to be merged
1562          * with the others.
1563          */
1564         ret = btrfs_drop_extents(trans, root, inode, file_pos,
1565                                  file_pos + num_bytes, locked_end,
1566                                  file_pos, &hint, 0);
1567         BUG_ON(ret);
1568
1569         ins.objectid = inode->i_ino;
1570         ins.offset = file_pos;
1571         ins.type = BTRFS_EXTENT_DATA_KEY;
1572         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1573         BUG_ON(ret);
1574         leaf = path->nodes[0];
1575         fi = btrfs_item_ptr(leaf, path->slots[0],
1576                             struct btrfs_file_extent_item);
1577         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1578         btrfs_set_file_extent_type(leaf, fi, extent_type);
1579         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1580         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1581         btrfs_set_file_extent_offset(leaf, fi, 0);
1582         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1583         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1584         btrfs_set_file_extent_compression(leaf, fi, compression);
1585         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1586         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1587
1588         btrfs_unlock_up_safe(path, 1);
1589         btrfs_set_lock_blocking(leaf);
1590
1591         btrfs_mark_buffer_dirty(leaf);
1592
1593         inode_add_bytes(inode, num_bytes);
1594
1595         ins.objectid = disk_bytenr;
1596         ins.offset = disk_num_bytes;
1597         ins.type = BTRFS_EXTENT_ITEM_KEY;
1598         ret = btrfs_alloc_reserved_file_extent(trans, root,
1599                                         root->root_key.objectid,
1600                                         inode->i_ino, file_pos, &ins);
1601         BUG_ON(ret);
1602         btrfs_free_path(path);
1603
1604         return 0;
1605 }
1606
1607 /*
1608  * helper function for btrfs_finish_ordered_io, this
1609  * just reads in some of the csum leaves to prime them into ram
1610  * before we start the transaction.  It limits the amount of btree
1611  * reads required while inside the transaction.
1612  */
1613 static noinline void reada_csum(struct btrfs_root *root,
1614                                 struct btrfs_path *path,
1615                                 struct btrfs_ordered_extent *ordered_extent)
1616 {
1617         struct btrfs_ordered_sum *sum;
1618         u64 bytenr;
1619
1620         sum = list_entry(ordered_extent->list.next, struct btrfs_ordered_sum,
1621                          list);
1622         bytenr = sum->sums[0].bytenr;
1623
1624         /*
1625          * we don't care about the results, the point of this search is
1626          * just to get the btree leaves into ram
1627          */
1628         btrfs_lookup_csum(NULL, root->fs_info->csum_root, path, bytenr, 0);
1629 }
1630
1631 /* as ordered data IO finishes, this gets called so we can finish
1632  * an ordered extent if the range of bytes in the file it covers are
1633  * fully written.
1634  */
1635 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1636 {
1637         struct btrfs_root *root = BTRFS_I(inode)->root;
1638         struct btrfs_trans_handle *trans;
1639         struct btrfs_ordered_extent *ordered_extent = NULL;
1640         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1641         struct btrfs_path *path;
1642         int compressed = 0;
1643         int ret;
1644
1645         ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
1646         if (!ret)
1647                 return 0;
1648
1649         /*
1650          * before we join the transaction, try to do some of our IO.
1651          * This will limit the amount of IO that we have to do with
1652          * the transaction running.  We're unlikely to need to do any
1653          * IO if the file extents are new, the disk_i_size checks
1654          * covers the most common case.
1655          */
1656         if (start < BTRFS_I(inode)->disk_i_size) {
1657                 path = btrfs_alloc_path();
1658                 if (path) {
1659                         ret = btrfs_lookup_file_extent(NULL, root, path,
1660                                                        inode->i_ino,
1661                                                        start, 0);
1662                         ordered_extent = btrfs_lookup_ordered_extent(inode,
1663                                                                      start);
1664                         if (!list_empty(&ordered_extent->list)) {
1665                                 btrfs_release_path(root, path);
1666                                 reada_csum(root, path, ordered_extent);
1667                         }
1668                         btrfs_free_path(path);
1669                 }
1670         }
1671
1672         trans = btrfs_join_transaction(root, 1);
1673
1674         if (!ordered_extent)
1675                 ordered_extent = btrfs_lookup_ordered_extent(inode, start);
1676         BUG_ON(!ordered_extent);
1677         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
1678                 goto nocow;
1679
1680         lock_extent(io_tree, ordered_extent->file_offset,
1681                     ordered_extent->file_offset + ordered_extent->len - 1,
1682                     GFP_NOFS);
1683
1684         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1685                 compressed = 1;
1686         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1687                 BUG_ON(compressed);
1688                 ret = btrfs_mark_extent_written(trans, root, inode,
1689                                                 ordered_extent->file_offset,
1690                                                 ordered_extent->file_offset +
1691                                                 ordered_extent->len);
1692                 BUG_ON(ret);
1693         } else {
1694                 ret = insert_reserved_file_extent(trans, inode,
1695                                                 ordered_extent->file_offset,
1696                                                 ordered_extent->start,
1697                                                 ordered_extent->disk_len,
1698                                                 ordered_extent->len,
1699                                                 ordered_extent->len,
1700                                                 ordered_extent->file_offset +
1701                                                 ordered_extent->len,
1702                                                 compressed, 0, 0,
1703                                                 BTRFS_FILE_EXTENT_REG);
1704                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1705                                    ordered_extent->file_offset,
1706                                    ordered_extent->len);
1707                 BUG_ON(ret);
1708         }
1709         unlock_extent(io_tree, ordered_extent->file_offset,
1710                     ordered_extent->file_offset + ordered_extent->len - 1,
1711                     GFP_NOFS);
1712 nocow:
1713         add_pending_csums(trans, inode, ordered_extent->file_offset,
1714                           &ordered_extent->list);
1715
1716         mutex_lock(&BTRFS_I(inode)->extent_mutex);
1717         btrfs_ordered_update_i_size(inode, ordered_extent);
1718         btrfs_update_inode(trans, root, inode);
1719         btrfs_remove_ordered_extent(inode, ordered_extent);
1720         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
1721
1722         /* once for us */
1723         btrfs_put_ordered_extent(ordered_extent);
1724         /* once for the tree */
1725         btrfs_put_ordered_extent(ordered_extent);
1726
1727         btrfs_end_transaction(trans, root);
1728         return 0;
1729 }
1730
1731 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1732                                 struct extent_state *state, int uptodate)
1733 {
1734         ClearPagePrivate2(page);
1735         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1736 }
1737
1738 /*
1739  * When IO fails, either with EIO or csum verification fails, we
1740  * try other mirrors that might have a good copy of the data.  This
1741  * io_failure_record is used to record state as we go through all the
1742  * mirrors.  If another mirror has good data, the page is set up to date
1743  * and things continue.  If a good mirror can't be found, the original
1744  * bio end_io callback is called to indicate things have failed.
1745  */
1746 struct io_failure_record {
1747         struct page *page;
1748         u64 start;
1749         u64 len;
1750         u64 logical;
1751         unsigned long bio_flags;
1752         int last_mirror;
1753 };
1754
1755 static int btrfs_io_failed_hook(struct bio *failed_bio,
1756                          struct page *page, u64 start, u64 end,
1757                          struct extent_state *state)
1758 {
1759         struct io_failure_record *failrec = NULL;
1760         u64 private;
1761         struct extent_map *em;
1762         struct inode *inode = page->mapping->host;
1763         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1764         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1765         struct bio *bio;
1766         int num_copies;
1767         int ret;
1768         int rw;
1769         u64 logical;
1770
1771         ret = get_state_private(failure_tree, start, &private);
1772         if (ret) {
1773                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1774                 if (!failrec)
1775                         return -ENOMEM;
1776                 failrec->start = start;
1777                 failrec->len = end - start + 1;
1778                 failrec->last_mirror = 0;
1779                 failrec->bio_flags = 0;
1780
1781                 read_lock(&em_tree->lock);
1782                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1783                 if (em->start > start || em->start + em->len < start) {
1784                         free_extent_map(em);
1785                         em = NULL;
1786                 }
1787                 read_unlock(&em_tree->lock);
1788
1789                 if (!em || IS_ERR(em)) {
1790                         kfree(failrec);
1791                         return -EIO;
1792                 }
1793                 logical = start - em->start;
1794                 logical = em->block_start + logical;
1795                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1796                         logical = em->block_start;
1797                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1798                 }
1799                 failrec->logical = logical;
1800                 free_extent_map(em);
1801                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1802                                 EXTENT_DIRTY, GFP_NOFS);
1803                 set_state_private(failure_tree, start,
1804                                  (u64)(unsigned long)failrec);
1805         } else {
1806                 failrec = (struct io_failure_record *)(unsigned long)private;
1807         }
1808         num_copies = btrfs_num_copies(
1809                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1810                               failrec->logical, failrec->len);
1811         failrec->last_mirror++;
1812         if (!state) {
1813                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1814                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1815                                                     failrec->start,
1816                                                     EXTENT_LOCKED);
1817                 if (state && state->start != failrec->start)
1818                         state = NULL;
1819                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1820         }
1821         if (!state || failrec->last_mirror > num_copies) {
1822                 set_state_private(failure_tree, failrec->start, 0);
1823                 clear_extent_bits(failure_tree, failrec->start,
1824                                   failrec->start + failrec->len - 1,
1825                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1826                 kfree(failrec);
1827                 return -EIO;
1828         }
1829         bio = bio_alloc(GFP_NOFS, 1);
1830         bio->bi_private = state;
1831         bio->bi_end_io = failed_bio->bi_end_io;
1832         bio->bi_sector = failrec->logical >> 9;
1833         bio->bi_bdev = failed_bio->bi_bdev;
1834         bio->bi_size = 0;
1835
1836         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1837         if (failed_bio->bi_rw & (1 << BIO_RW))
1838                 rw = WRITE;
1839         else
1840                 rw = READ;
1841
1842         BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1843                                                       failrec->last_mirror,
1844                                                       failrec->bio_flags);
1845         return 0;
1846 }
1847
1848 /*
1849  * each time an IO finishes, we do a fast check in the IO failure tree
1850  * to see if we need to process or clean up an io_failure_record
1851  */
1852 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1853 {
1854         u64 private;
1855         u64 private_failure;
1856         struct io_failure_record *failure;
1857         int ret;
1858
1859         private = 0;
1860         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1861                              (u64)-1, 1, EXTENT_DIRTY)) {
1862                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1863                                         start, &private_failure);
1864                 if (ret == 0) {
1865                         failure = (struct io_failure_record *)(unsigned long)
1866                                    private_failure;
1867                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1868                                           failure->start, 0);
1869                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1870                                           failure->start,
1871                                           failure->start + failure->len - 1,
1872                                           EXTENT_DIRTY | EXTENT_LOCKED,
1873                                           GFP_NOFS);
1874                         kfree(failure);
1875                 }
1876         }
1877         return 0;
1878 }
1879
1880 /*
1881  * when reads are done, we need to check csums to verify the data is correct
1882  * if there's a match, we allow the bio to finish.  If not, we go through
1883  * the io_failure_record routines to find good copies
1884  */
1885 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1886                                struct extent_state *state)
1887 {
1888         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1889         struct inode *inode = page->mapping->host;
1890         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1891         char *kaddr;
1892         u64 private = ~(u32)0;
1893         int ret;
1894         struct btrfs_root *root = BTRFS_I(inode)->root;
1895         u32 csum = ~(u32)0;
1896
1897         if (PageChecked(page)) {
1898                 ClearPageChecked(page);
1899                 goto good;
1900         }
1901
1902         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1903                 return 0;
1904
1905         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1906             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1907                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1908                                   GFP_NOFS);
1909                 return 0;
1910         }
1911
1912         if (state && state->start == start) {
1913                 private = state->private;
1914                 ret = 0;
1915         } else {
1916                 ret = get_state_private(io_tree, start, &private);
1917         }
1918         kaddr = kmap_atomic(page, KM_USER0);
1919         if (ret)
1920                 goto zeroit;
1921
1922         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1923         btrfs_csum_final(csum, (char *)&csum);
1924         if (csum != private)
1925                 goto zeroit;
1926
1927         kunmap_atomic(kaddr, KM_USER0);
1928 good:
1929         /* if the io failure tree for this inode is non-empty,
1930          * check to see if we've recovered from a failed IO
1931          */
1932         btrfs_clean_io_failures(inode, start);
1933         return 0;
1934
1935 zeroit:
1936         if (printk_ratelimit()) {
1937                 printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
1938                        "private %llu\n", page->mapping->host->i_ino,
1939                        (unsigned long long)start, csum,
1940                        (unsigned long long)private);
1941         }
1942         memset(kaddr + offset, 1, end - start + 1);
1943         flush_dcache_page(page);
1944         kunmap_atomic(kaddr, KM_USER0);
1945         if (private == 0)
1946                 return 0;
1947         return -EIO;
1948 }
1949
1950 /*
1951  * This creates an orphan entry for the given inode in case something goes
1952  * wrong in the middle of an unlink/truncate.
1953  */
1954 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
1955 {
1956         struct btrfs_root *root = BTRFS_I(inode)->root;
1957         int ret = 0;
1958
1959         spin_lock(&root->list_lock);
1960
1961         /* already on the orphan list, we're good */
1962         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
1963                 spin_unlock(&root->list_lock);
1964                 return 0;
1965         }
1966
1967         list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
1968
1969         spin_unlock(&root->list_lock);
1970
1971         /*
1972          * insert an orphan item to track this unlinked/truncated file
1973          */
1974         ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
1975
1976         return ret;
1977 }
1978
1979 /*
1980  * We have done the truncate/delete so we can go ahead and remove the orphan
1981  * item for this particular inode.
1982  */
1983 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
1984 {
1985         struct btrfs_root *root = BTRFS_I(inode)->root;
1986         int ret = 0;
1987
1988         spin_lock(&root->list_lock);
1989
1990         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
1991                 spin_unlock(&root->list_lock);
1992                 return 0;
1993         }
1994
1995         list_del_init(&BTRFS_I(inode)->i_orphan);
1996         if (!trans) {
1997                 spin_unlock(&root->list_lock);
1998                 return 0;
1999         }
2000
2001         spin_unlock(&root->list_lock);
2002
2003         ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
2004
2005         return ret;
2006 }
2007
2008 /*
2009  * this cleans up any orphans that may be left on the list from the last use
2010  * of this root.
2011  */
2012 void btrfs_orphan_cleanup(struct btrfs_root *root)
2013 {
2014         struct btrfs_path *path;
2015         struct extent_buffer *leaf;
2016         struct btrfs_item *item;
2017         struct btrfs_key key, found_key;
2018         struct btrfs_trans_handle *trans;
2019         struct inode *inode;
2020         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2021
2022         path = btrfs_alloc_path();
2023         if (!path)
2024                 return;
2025         path->reada = -1;
2026
2027         key.objectid = BTRFS_ORPHAN_OBJECTID;
2028         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2029         key.offset = (u64)-1;
2030
2031
2032         while (1) {
2033                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2034                 if (ret < 0) {
2035                         printk(KERN_ERR "Error searching slot for orphan: %d"
2036                                "\n", ret);
2037                         break;
2038                 }
2039
2040                 /*
2041                  * if ret == 0 means we found what we were searching for, which
2042                  * is weird, but possible, so only screw with path if we didnt
2043                  * find the key and see if we have stuff that matches
2044                  */
2045                 if (ret > 0) {
2046                         if (path->slots[0] == 0)
2047                                 break;
2048                         path->slots[0]--;
2049                 }
2050
2051                 /* pull out the item */
2052                 leaf = path->nodes[0];
2053                 item = btrfs_item_nr(leaf, path->slots[0]);
2054                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2055
2056                 /* make sure the item matches what we want */
2057                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2058                         break;
2059                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2060                         break;
2061
2062                 /* release the path since we're done with it */
2063                 btrfs_release_path(root, path);
2064
2065                 /*
2066                  * this is where we are basically btrfs_lookup, without the
2067                  * crossing root thing.  we store the inode number in the
2068                  * offset of the orphan item.
2069                  */
2070                 found_key.objectid = found_key.offset;
2071                 found_key.type = BTRFS_INODE_ITEM_KEY;
2072                 found_key.offset = 0;
2073                 inode = btrfs_iget(root->fs_info->sb, &found_key, root);
2074                 if (IS_ERR(inode))
2075                         break;
2076
2077                 /*
2078                  * add this inode to the orphan list so btrfs_orphan_del does
2079                  * the proper thing when we hit it
2080                  */
2081                 spin_lock(&root->list_lock);
2082                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2083                 spin_unlock(&root->list_lock);
2084
2085                 /*
2086                  * if this is a bad inode, means we actually succeeded in
2087                  * removing the inode, but not the orphan record, which means
2088                  * we need to manually delete the orphan since iput will just
2089                  * do a destroy_inode
2090                  */
2091                 if (is_bad_inode(inode)) {
2092                         trans = btrfs_start_transaction(root, 1);
2093                         btrfs_orphan_del(trans, inode);
2094                         btrfs_end_transaction(trans, root);
2095                         iput(inode);
2096                         continue;
2097                 }
2098
2099                 /* if we have links, this was a truncate, lets do that */
2100                 if (inode->i_nlink) {
2101                         nr_truncate++;
2102                         btrfs_truncate(inode);
2103                 } else {
2104                         nr_unlink++;
2105                 }
2106
2107                 /* this will do delete_inode and everything for us */
2108                 iput(inode);
2109         }
2110
2111         if (nr_unlink)
2112                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2113         if (nr_truncate)
2114                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2115
2116         btrfs_free_path(path);
2117 }
2118
2119 /*
2120  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2121  * don't find any xattrs, we know there can't be any acls.
2122  *
2123  * slot is the slot the inode is in, objectid is the objectid of the inode
2124  */
2125 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2126                                           int slot, u64 objectid)
2127 {
2128         u32 nritems = btrfs_header_nritems(leaf);
2129         struct btrfs_key found_key;
2130         int scanned = 0;
2131
2132         slot++;
2133         while (slot < nritems) {
2134                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2135
2136                 /* we found a different objectid, there must not be acls */
2137                 if (found_key.objectid != objectid)
2138                         return 0;
2139
2140                 /* we found an xattr, assume we've got an acl */
2141                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2142                         return 1;
2143
2144                 /*
2145                  * we found a key greater than an xattr key, there can't
2146                  * be any acls later on
2147                  */
2148                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2149                         return 0;
2150
2151                 slot++;
2152                 scanned++;
2153
2154                 /*
2155                  * it goes inode, inode backrefs, xattrs, extents,
2156                  * so if there are a ton of hard links to an inode there can
2157                  * be a lot of backrefs.  Don't waste time searching too hard,
2158                  * this is just an optimization
2159                  */
2160                 if (scanned >= 8)
2161                         break;
2162         }
2163         /* we hit the end of the leaf before we found an xattr or
2164          * something larger than an xattr.  We have to assume the inode
2165          * has acls
2166          */
2167         return 1;
2168 }
2169
2170 /*
2171  * read an inode from the btree into the in-memory inode
2172  */
2173 static void btrfs_read_locked_inode(struct inode *inode)
2174 {
2175         struct btrfs_path *path;
2176         struct extent_buffer *leaf;
2177         struct btrfs_inode_item *inode_item;
2178         struct btrfs_timespec *tspec;
2179         struct btrfs_root *root = BTRFS_I(inode)->root;
2180         struct btrfs_key location;
2181         int maybe_acls;
2182         u64 alloc_group_block;
2183         u32 rdev;
2184         int ret;
2185
2186         path = btrfs_alloc_path();
2187         BUG_ON(!path);
2188         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2189
2190         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2191         if (ret)
2192                 goto make_bad;
2193
2194         leaf = path->nodes[0];
2195         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2196                                     struct btrfs_inode_item);
2197
2198         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2199         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2200         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2201         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2202         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2203
2204         tspec = btrfs_inode_atime(inode_item);
2205         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2206         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2207
2208         tspec = btrfs_inode_mtime(inode_item);
2209         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2210         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2211
2212         tspec = btrfs_inode_ctime(inode_item);
2213         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2214         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2215
2216         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2217         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2218         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2219         inode->i_generation = BTRFS_I(inode)->generation;
2220         inode->i_rdev = 0;
2221         rdev = btrfs_inode_rdev(leaf, inode_item);
2222
2223         BTRFS_I(inode)->index_cnt = (u64)-1;
2224         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2225
2226         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2227
2228         /*
2229          * try to precache a NULL acl entry for files that don't have
2230          * any xattrs or acls
2231          */
2232         maybe_acls = acls_after_inode_item(leaf, path->slots[0], inode->i_ino);
2233         if (!maybe_acls)
2234                 cache_no_acl(inode);
2235
2236         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2237                                                 alloc_group_block, 0);
2238         btrfs_free_path(path);
2239         inode_item = NULL;
2240
2241         switch (inode->i_mode & S_IFMT) {
2242         case S_IFREG:
2243                 inode->i_mapping->a_ops = &btrfs_aops;
2244                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2245                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2246                 inode->i_fop = &btrfs_file_operations;
2247                 inode->i_op = &btrfs_file_inode_operations;
2248                 break;
2249         case S_IFDIR:
2250                 inode->i_fop = &btrfs_dir_file_operations;
2251                 if (root == root->fs_info->tree_root)
2252                         inode->i_op = &btrfs_dir_ro_inode_operations;
2253                 else
2254                         inode->i_op = &btrfs_dir_inode_operations;
2255                 break;
2256         case S_IFLNK:
2257                 inode->i_op = &btrfs_symlink_inode_operations;
2258                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2259                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2260                 break;
2261         default:
2262                 inode->i_op = &btrfs_special_inode_operations;
2263                 init_special_inode(inode, inode->i_mode, rdev);
2264                 break;
2265         }
2266
2267         btrfs_update_iflags(inode);
2268         return;
2269
2270 make_bad:
2271         btrfs_free_path(path);
2272         make_bad_inode(inode);
2273 }
2274
2275 /*
2276  * given a leaf and an inode, copy the inode fields into the leaf
2277  */
2278 static void fill_inode_item(struct btrfs_trans_handle *trans,
2279                             struct extent_buffer *leaf,
2280                             struct btrfs_inode_item *item,
2281                             struct inode *inode)
2282 {
2283         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2284         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2285         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2286         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2287         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2288
2289         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2290                                inode->i_atime.tv_sec);
2291         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2292                                 inode->i_atime.tv_nsec);
2293
2294         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2295                                inode->i_mtime.tv_sec);
2296         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2297                                 inode->i_mtime.tv_nsec);
2298
2299         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2300                                inode->i_ctime.tv_sec);
2301         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2302                                 inode->i_ctime.tv_nsec);
2303
2304         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2305         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2306         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2307         btrfs_set_inode_transid(leaf, item, trans->transid);
2308         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2309         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2310         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2311 }
2312
2313 /*
2314  * copy everything in the in-memory inode into the btree.
2315  */
2316 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2317                                 struct btrfs_root *root, struct inode *inode)
2318 {
2319         struct btrfs_inode_item *inode_item;
2320         struct btrfs_path *path;
2321         struct extent_buffer *leaf;
2322         int ret;
2323
2324         path = btrfs_alloc_path();
2325         BUG_ON(!path);
2326         path->leave_spinning = 1;
2327         ret = btrfs_lookup_inode(trans, root, path,
2328                                  &BTRFS_I(inode)->location, 1);
2329         if (ret) {
2330                 if (ret > 0)
2331                         ret = -ENOENT;
2332                 goto failed;
2333         }
2334
2335         btrfs_unlock_up_safe(path, 1);
2336         leaf = path->nodes[0];
2337         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2338                                   struct btrfs_inode_item);
2339
2340         fill_inode_item(trans, leaf, inode_item, inode);
2341         btrfs_mark_buffer_dirty(leaf);
2342         btrfs_set_inode_last_trans(trans, inode);
2343         ret = 0;
2344 failed:
2345         btrfs_free_path(path);
2346         return ret;
2347 }
2348
2349
2350 /*
2351  * unlink helper that gets used here in inode.c and in the tree logging
2352  * recovery code.  It remove a link in a directory with a given name, and
2353  * also drops the back refs in the inode to the directory
2354  */
2355 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2356                        struct btrfs_root *root,
2357                        struct inode *dir, struct inode *inode,
2358                        const char *name, int name_len)
2359 {
2360         struct btrfs_path *path;
2361         int ret = 0;
2362         struct extent_buffer *leaf;
2363         struct btrfs_dir_item *di;
2364         struct btrfs_key key;
2365         u64 index;
2366
2367         path = btrfs_alloc_path();
2368         if (!path) {
2369                 ret = -ENOMEM;
2370                 goto err;
2371         }
2372
2373         path->leave_spinning = 1;
2374         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2375                                     name, name_len, -1);
2376         if (IS_ERR(di)) {
2377                 ret = PTR_ERR(di);
2378                 goto err;
2379         }
2380         if (!di) {
2381                 ret = -ENOENT;
2382                 goto err;
2383         }
2384         leaf = path->nodes[0];
2385         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2386         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2387         if (ret)
2388                 goto err;
2389         btrfs_release_path(root, path);
2390
2391         ret = btrfs_del_inode_ref(trans, root, name, name_len,
2392                                   inode->i_ino,
2393                                   dir->i_ino, &index);
2394         if (ret) {
2395                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2396                        "inode %lu parent %lu\n", name_len, name,
2397                        inode->i_ino, dir->i_ino);
2398                 goto err;
2399         }
2400
2401         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2402                                          index, name, name_len, -1);
2403         if (IS_ERR(di)) {
2404                 ret = PTR_ERR(di);
2405                 goto err;
2406         }
2407         if (!di) {
2408                 ret = -ENOENT;
2409                 goto err;
2410         }
2411         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2412         btrfs_release_path(root, path);
2413
2414         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2415                                          inode, dir->i_ino);
2416         BUG_ON(ret != 0 && ret != -ENOENT);
2417
2418         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2419                                            dir, index);
2420         BUG_ON(ret);
2421 err:
2422         btrfs_free_path(path);
2423         if (ret)
2424                 goto out;
2425
2426         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2427         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2428         btrfs_update_inode(trans, root, dir);
2429         btrfs_drop_nlink(inode);
2430         ret = btrfs_update_inode(trans, root, inode);
2431 out:
2432         return ret;
2433 }
2434
2435 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2436 {
2437         struct btrfs_root *root;
2438         struct btrfs_trans_handle *trans;
2439         struct inode *inode = dentry->d_inode;
2440         int ret;
2441         unsigned long nr = 0;
2442
2443         root = BTRFS_I(dir)->root;
2444
2445         trans = btrfs_start_transaction(root, 1);
2446
2447         btrfs_set_trans_block_group(trans, dir);
2448
2449         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2450
2451         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2452                                  dentry->d_name.name, dentry->d_name.len);
2453
2454         if (inode->i_nlink == 0)
2455                 ret = btrfs_orphan_add(trans, inode);
2456
2457         nr = trans->blocks_used;
2458
2459         btrfs_end_transaction_throttle(trans, root);
2460         btrfs_btree_balance_dirty(root, nr);
2461         return ret;
2462 }
2463
2464 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
2465                         struct btrfs_root *root,
2466                         struct inode *dir, u64 objectid,
2467                         const char *name, int name_len)
2468 {
2469         struct btrfs_path *path;
2470         struct extent_buffer *leaf;
2471         struct btrfs_dir_item *di;
2472         struct btrfs_key key;
2473         u64 index;
2474         int ret;
2475
2476         path = btrfs_alloc_path();
2477         if (!path)
2478                 return -ENOMEM;
2479
2480         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2481                                    name, name_len, -1);
2482         BUG_ON(!di || IS_ERR(di));
2483
2484         leaf = path->nodes[0];
2485         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2486         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2487         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2488         BUG_ON(ret);
2489         btrfs_release_path(root, path);
2490
2491         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
2492                                  objectid, root->root_key.objectid,
2493                                  dir->i_ino, &index, name, name_len);
2494         if (ret < 0) {
2495                 BUG_ON(ret != -ENOENT);
2496                 di = btrfs_search_dir_index_item(root, path, dir->i_ino,
2497                                                  name, name_len);
2498                 BUG_ON(!di || IS_ERR(di));
2499
2500                 leaf = path->nodes[0];
2501                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2502                 btrfs_release_path(root, path);
2503                 index = key.offset;
2504         }
2505
2506         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2507                                          index, name, name_len, -1);
2508         BUG_ON(!di || IS_ERR(di));
2509
2510         leaf = path->nodes[0];
2511         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2512         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2513         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2514         BUG_ON(ret);
2515         btrfs_release_path(root, path);
2516
2517         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2518         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2519         ret = btrfs_update_inode(trans, root, dir);
2520         BUG_ON(ret);
2521         dir->i_sb->s_dirt = 1;
2522
2523         btrfs_free_path(path);
2524         return 0;
2525 }
2526
2527 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
2528 {
2529         struct inode *inode = dentry->d_inode;
2530         int err = 0;
2531         int ret;
2532         struct btrfs_root *root = BTRFS_I(dir)->root;
2533         struct btrfs_trans_handle *trans;
2534         unsigned long nr = 0;
2535
2536         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
2537             inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
2538                 return -ENOTEMPTY;
2539
2540         trans = btrfs_start_transaction(root, 1);
2541         btrfs_set_trans_block_group(trans, dir);
2542
2543         if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
2544                 err = btrfs_unlink_subvol(trans, root, dir,
2545                                           BTRFS_I(inode)->location.objectid,
2546                                           dentry->d_name.name,
2547                                           dentry->d_name.len);
2548                 goto out;
2549         }
2550
2551         err = btrfs_orphan_add(trans, inode);
2552         if (err)
2553                 goto out;
2554
2555         /* now the directory is empty */
2556         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2557                                  dentry->d_name.name, dentry->d_name.len);
2558         if (!err)
2559                 btrfs_i_size_write(inode, 0);
2560 out:
2561         nr = trans->blocks_used;
2562         ret = btrfs_end_transaction_throttle(trans, root);
2563         btrfs_btree_balance_dirty(root, nr);
2564
2565         if (ret && !err)
2566                 err = ret;
2567         return err;
2568 }
2569
2570 #if 0
2571 /*
2572  * when truncating bytes in a file, it is possible to avoid reading
2573  * the leaves that contain only checksum items.  This can be the
2574  * majority of the IO required to delete a large file, but it must
2575  * be done carefully.
2576  *
2577  * The keys in the level just above the leaves are checked to make sure
2578  * the lowest key in a given leaf is a csum key, and starts at an offset
2579  * after the new  size.
2580  *
2581  * Then the key for the next leaf is checked to make sure it also has
2582  * a checksum item for the same file.  If it does, we know our target leaf
2583  * contains only checksum items, and it can be safely freed without reading
2584  * it.
2585  *
2586  * This is just an optimization targeted at large files.  It may do
2587  * nothing.  It will return 0 unless things went badly.
2588  */
2589 static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
2590                                      struct btrfs_root *root,
2591                                      struct btrfs_path *path,
2592                                      struct inode *inode, u64 new_size)
2593 {
2594         struct btrfs_key key;
2595         int ret;
2596         int nritems;
2597         struct btrfs_key found_key;
2598         struct btrfs_key other_key;
2599         struct btrfs_leaf_ref *ref;
2600         u64 leaf_gen;
2601         u64 leaf_start;
2602
2603         path->lowest_level = 1;
2604         key.objectid = inode->i_ino;
2605         key.type = BTRFS_CSUM_ITEM_KEY;
2606         key.offset = new_size;
2607 again:
2608         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2609         if (ret < 0)
2610                 goto out;
2611
2612         if (path->nodes[1] == NULL) {
2613                 ret = 0;
2614                 goto out;
2615         }
2616         ret = 0;
2617         btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
2618         nritems = btrfs_header_nritems(path->nodes[1]);
2619
2620         if (!nritems)
2621                 goto out;
2622
2623         if (path->slots[1] >= nritems)
2624                 goto next_node;
2625
2626         /* did we find a key greater than anything we want to delete? */
2627         if (found_key.objectid > inode->i_ino ||
2628            (found_key.objectid == inode->i_ino && found_key.type > key.type))
2629                 goto out;
2630
2631         /* we check the next key in the node to make sure the leave contains
2632          * only checksum items.  This comparison doesn't work if our
2633          * leaf is the last one in the node
2634          */
2635         if (path->slots[1] + 1 >= nritems) {
2636 next_node:
2637                 /* search forward from the last key in the node, this
2638                  * will bring us into the next node in the tree
2639                  */
2640                 btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
2641
2642                 /* unlikely, but we inc below, so check to be safe */
2643                 if (found_key.offset == (u64)-1)
2644                         goto out;
2645
2646                 /* search_forward needs a path with locks held, do the
2647                  * search again for the original key.  It is possible
2648                  * this will race with a balance and return a path that
2649                  * we could modify, but this drop is just an optimization
2650                  * and is allowed to miss some leaves.
2651                  */
2652                 btrfs_release_path(root, path);
2653                 found_key.offset++;
2654
2655                 /* setup a max key for search_forward */
2656                 other_key.offset = (u64)-1;
2657                 other_key.type = key.type;
2658                 other_key.objectid = key.objectid;
2659
2660                 path->keep_locks = 1;
2661                 ret = btrfs_search_forward(root, &found_key, &other_key,
2662                                            path, 0, 0);
2663                 path->keep_locks = 0;
2664                 if (ret || found_key.objectid != key.objectid ||
2665                     found_key.type != key.type) {
2666                         ret = 0;
2667                         goto out;
2668                 }
2669
2670                 key.offset = found_key.offset;
2671                 btrfs_release_path(root, path);
2672                 cond_resched();
2673                 goto again;
2674         }
2675
2676         /* we know there's one more slot after us in the tree,
2677          * read that key so we can verify it is also a checksum item
2678          */
2679         btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
2680
2681         if (found_key.objectid < inode->i_ino)
2682                 goto next_key;
2683
2684         if (found_key.type != key.type || found_key.offset < new_size)
2685                 goto next_key;
2686
2687         /*
2688          * if the key for the next leaf isn't a csum key from this objectid,
2689          * we can't be sure there aren't good items inside this leaf.
2690          * Bail out
2691          */
2692         if (other_key.objectid != inode->i_ino || other_key.type != key.type)
2693                 goto out;
2694
2695         leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
2696         leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
2697         /*
2698          * it is safe to delete this leaf, it contains only
2699          * csum items from this inode at an offset >= new_size
2700          */
2701         ret = btrfs_del_leaf(trans, root, path, leaf_start);
2702         BUG_ON(ret);
2703
2704         if (root->ref_cows && leaf_gen < trans->transid) {
2705                 ref = btrfs_alloc_leaf_ref(root, 0);
2706                 if (ref) {
2707                         ref->root_gen = root->root_key.offset;
2708                         ref->bytenr = leaf_start;
2709                         ref->owner = 0;
2710                         ref->generation = leaf_gen;
2711                         ref->nritems = 0;
2712
2713                         btrfs_sort_leaf_ref(ref);
2714
2715                         ret = btrfs_add_leaf_ref(root, ref, 0);
2716                         WARN_ON(ret);
2717                         btrfs_free_leaf_ref(root, ref);
2718                 } else {
2719                         WARN_ON(1);
2720                 }
2721         }
2722 next_key:
2723         btrfs_release_path(root, path);
2724
2725         if (other_key.objectid == inode->i_ino &&
2726             other_key.type == key.type && other_key.offset > key.offset) {
2727                 key.offset = other_key.offset;
2728                 cond_resched();
2729                 goto again;
2730         }
2731         ret = 0;
2732 out:
2733         /* fixup any changes we've made to the path */
2734         path->lowest_level = 0;
2735         path->keep_locks = 0;
2736         btrfs_release_path(root, path);
2737         return ret;
2738 }
2739
2740 #endif
2741
2742 /*
2743  * this can truncate away extent items, csum items and directory items.
2744  * It starts at a high offset and removes keys until it can't find
2745  * any higher than new_size
2746  *
2747  * csum items that cross the new i_size are truncated to the new size
2748  * as well.
2749  *
2750  * min_type is the minimum key type to truncate down to.  If set to 0, this
2751  * will kill all the items on this inode, including the INODE_ITEM_KEY.
2752  */
2753 noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
2754                                         struct btrfs_root *root,
2755                                         struct inode *inode,
2756                                         u64 new_size, u32 min_type)
2757 {
2758         int ret;
2759         struct btrfs_path *path;
2760         struct btrfs_key key;
2761         struct btrfs_key found_key;
2762         u32 found_type = (u8)-1;
2763         struct extent_buffer *leaf;
2764         struct btrfs_file_extent_item *fi;
2765         u64 extent_start = 0;
2766         u64 extent_num_bytes = 0;
2767         u64 extent_offset = 0;
2768         u64 item_end = 0;
2769         int found_extent;
2770         int del_item;
2771         int pending_del_nr = 0;
2772         int pending_del_slot = 0;
2773         int extent_type = -1;
2774         int encoding;
2775         u64 mask = root->sectorsize - 1;
2776
2777         if (root->ref_cows)
2778                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
2779         path = btrfs_alloc_path();
2780         BUG_ON(!path);
2781         path->reada = -1;
2782
2783         /* FIXME, add redo link to tree so we don't leak on crash */
2784         key.objectid = inode->i_ino;
2785         key.offset = (u64)-1;
2786         key.type = (u8)-1;
2787
2788 search_again:
2789         path->leave_spinning = 1;
2790         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2791         if (ret < 0)
2792                 goto error;
2793
2794         if (ret > 0) {
2795                 /* there are no items in the tree for us to truncate, we're
2796                  * done
2797                  */
2798                 if (path->slots[0] == 0) {
2799                         ret = 0;
2800                         goto error;
2801                 }
2802                 path->slots[0]--;
2803         }
2804
2805         while (1) {
2806                 fi = NULL;
2807                 leaf = path->nodes[0];
2808                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2809                 found_type = btrfs_key_type(&found_key);
2810                 encoding = 0;
2811
2812                 if (found_key.objectid != inode->i_ino)
2813                         break;
2814
2815                 if (found_type < min_type)
2816                         break;
2817
2818                 item_end = found_key.offset;
2819                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
2820                         fi = btrfs_item_ptr(leaf, path->slots[0],
2821                                             struct btrfs_file_extent_item);
2822                         extent_type = btrfs_file_extent_type(leaf, fi);
2823                         encoding = btrfs_file_extent_compression(leaf, fi);
2824                         encoding |= btrfs_file_extent_encryption(leaf, fi);
2825                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
2826
2827                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
2828                                 item_end +=
2829                                     btrfs_file_extent_num_bytes(leaf, fi);
2830                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
2831                                 item_end += btrfs_file_extent_inline_len(leaf,
2832                                                                          fi);
2833                         }
2834                         item_end--;
2835                 }
2836                 if (item_end < new_size) {
2837                         if (found_type == BTRFS_DIR_ITEM_KEY)
2838                                 found_type = BTRFS_INODE_ITEM_KEY;
2839                         else if (found_type == BTRFS_EXTENT_ITEM_KEY)
2840                                 found_type = BTRFS_EXTENT_DATA_KEY;
2841                         else if (found_type == BTRFS_EXTENT_DATA_KEY)
2842                                 found_type = BTRFS_XATTR_ITEM_KEY;
2843                         else if (found_type == BTRFS_XATTR_ITEM_KEY)
2844                                 found_type = BTRFS_INODE_REF_KEY;
2845                         else if (found_type)
2846                                 found_type--;
2847                         else
2848                                 break;
2849                         btrfs_set_key_type(&key, found_type);
2850                         goto next;
2851                 }
2852                 if (found_key.offset >= new_size)
2853                         del_item = 1;
2854                 else
2855                         del_item = 0;
2856                 found_extent = 0;
2857
2858                 /* FIXME, shrink the extent if the ref count is only 1 */
2859                 if (found_type != BTRFS_EXTENT_DATA_KEY)
2860                         goto delete;
2861
2862                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
2863                         u64 num_dec;
2864                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
2865                         if (!del_item && !encoding) {
2866                                 u64 orig_num_bytes =
2867                                         btrfs_file_extent_num_bytes(leaf, fi);
2868                                 extent_num_bytes = new_size -
2869                                         found_key.offset + root->sectorsize - 1;
2870                                 extent_num_bytes = extent_num_bytes &
2871                                         ~((u64)root->sectorsize - 1);
2872                                 btrfs_set_file_extent_num_bytes(leaf, fi,
2873                                                          extent_num_bytes);
2874                                 num_dec = (orig_num_bytes -
2875                                            extent_num_bytes);
2876                                 if (root->ref_cows && extent_start != 0)
2877                                         inode_sub_bytes(inode, num_dec);
2878                                 btrfs_mark_buffer_dirty(leaf);
2879                         } else {
2880                                 extent_num_bytes =
2881                                         btrfs_file_extent_disk_num_bytes(leaf,
2882                                                                          fi);
2883                                 extent_offset = found_key.offset -
2884                                         btrfs_file_extent_offset(leaf, fi);
2885
2886                                 /* FIXME blocksize != 4096 */
2887                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
2888                                 if (extent_start != 0) {
2889                                         found_extent = 1;
2890                                         if (root->ref_cows)
2891                                                 inode_sub_bytes(inode, num_dec);
2892                                 }
2893                         }
2894                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
2895                         /*
2896                          * we can't truncate inline items that have had
2897                          * special encodings
2898                          */
2899                         if (!del_item &&
2900                             btrfs_file_extent_compression(leaf, fi) == 0 &&
2901                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
2902                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
2903                                 u32 size = new_size - found_key.offset;
2904
2905                                 if (root->ref_cows) {
2906                                         inode_sub_bytes(inode, item_end + 1 -
2907                                                         new_size);
2908                                 }
2909                                 size =
2910                                     btrfs_file_extent_calc_inline_size(size);
2911                                 ret = btrfs_truncate_item(trans, root, path,
2912                                                           size, 1);
2913                                 BUG_ON(ret);
2914                         } else if (root->ref_cows) {
2915                                 inode_sub_bytes(inode, item_end + 1 -
2916                                                 found_key.offset);
2917                         }
2918                 }
2919 delete:
2920                 if (del_item) {
2921                         if (!pending_del_nr) {
2922                                 /* no pending yet, add ourselves */
2923                                 pending_del_slot = path->slots[0];
2924                                 pending_del_nr = 1;
2925                         } else if (pending_del_nr &&
2926                                    path->slots[0] + 1 == pending_del_slot) {
2927                                 /* hop on the pending chunk */
2928                                 pending_del_nr++;
2929                                 pending_del_slot = path->slots[0];
2930                         } else {
2931                                 BUG();
2932                         }
2933                 } else {
2934                         break;
2935                 }
2936                 if (found_extent && root->ref_cows) {
2937                         btrfs_set_path_blocking(path);
2938                         ret = btrfs_free_extent(trans, root, extent_start,
2939                                                 extent_num_bytes, 0,
2940                                                 btrfs_header_owner(leaf),
2941                                                 inode->i_ino, extent_offset);
2942                         BUG_ON(ret);
2943                 }
2944 next:
2945                 if (path->slots[0] == 0) {
2946                         if (pending_del_nr)
2947                                 goto del_pending;
2948                         btrfs_release_path(root, path);
2949                         if (found_type == BTRFS_INODE_ITEM_KEY)
2950                                 break;
2951                         goto search_again;
2952                 }
2953
2954                 path->slots[0]--;
2955                 if (pending_del_nr &&
2956                     path->slots[0] + 1 != pending_del_slot) {
2957                         struct btrfs_key debug;
2958 del_pending:
2959                         btrfs_item_key_to_cpu(path->nodes[0], &debug,
2960                                               pending_del_slot);
2961                         ret = btrfs_del_items(trans, root, path,
2962                                               pending_del_slot,
2963                                               pending_del_nr);
2964                         BUG_ON(ret);
2965                         pending_del_nr = 0;
2966                         btrfs_release_path(root, path);
2967                         if (found_type == BTRFS_INODE_ITEM_KEY)
2968                                 break;
2969                         goto search_again;
2970                 }
2971         }
2972         ret = 0;
2973 error:
2974         if (pending_del_nr) {
2975                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
2976                                       pending_del_nr);
2977         }
2978         btrfs_free_path(path);
2979         return ret;
2980 }
2981
2982 /*
2983  * taken from block_truncate_page, but does cow as it zeros out
2984  * any bytes left in the last page in the file.
2985  */
2986 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
2987 {
2988         struct inode *inode = mapping->host;
2989         struct btrfs_root *root = BTRFS_I(inode)->root;
2990         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2991         struct btrfs_ordered_extent *ordered;
2992         char *kaddr;
2993         u32 blocksize = root->sectorsize;
2994         pgoff_t index = from >> PAGE_CACHE_SHIFT;
2995         unsigned offset = from & (PAGE_CACHE_SIZE-1);
2996         struct page *page;
2997         int ret = 0;
2998         u64 page_start;
2999         u64 page_end;
3000
3001         if ((offset & (blocksize - 1)) == 0)
3002                 goto out;
3003
3004         ret = -ENOMEM;
3005 again:
3006         page = grab_cache_page(mapping, index);
3007         if (!page)
3008                 goto out;
3009
3010         page_start = page_offset(page);
3011         page_end = page_start + PAGE_CACHE_SIZE - 1;
3012
3013         if (!PageUptodate(page)) {
3014                 ret = btrfs_readpage(NULL, page);
3015                 lock_page(page);
3016                 if (page->mapping != mapping) {
3017                         unlock_page(page);
3018                         page_cache_release(page);
3019                         goto again;
3020                 }
3021                 if (!PageUptodate(page)) {
3022                         ret = -EIO;
3023                         goto out_unlock;
3024                 }
3025         }
3026         wait_on_page_writeback(page);
3027
3028         lock_extent(io_tree, page_start, page_end, GFP_NOFS);
3029         set_page_extent_mapped(page);
3030
3031         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3032         if (ordered) {
3033                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3034                 unlock_page(page);
3035                 page_cache_release(page);
3036                 btrfs_start_ordered_extent(inode, ordered, 1);
3037                 btrfs_put_ordered_extent(ordered);
3038                 goto again;
3039         }
3040
3041         ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
3042         if (ret) {
3043                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3044                 goto out_unlock;
3045         }
3046
3047         ret = 0;
3048         if (offset != PAGE_CACHE_SIZE) {
3049                 kaddr = kmap(page);
3050                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3051                 flush_dcache_page(page);
3052                 kunmap(page);
3053         }
3054         ClearPageChecked(page);
3055         set_page_dirty(page);
3056         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3057
3058 out_unlock:
3059         unlock_page(page);
3060         page_cache_release(page);
3061 out:
3062         return ret;
3063 }
3064
3065 int btrfs_cont_expand(struct inode *inode, loff_t size)
3066 {
3067         struct btrfs_trans_handle *trans;
3068         struct btrfs_root *root = BTRFS_I(inode)->root;
3069         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3070         struct extent_map *em;
3071         u64 mask = root->sectorsize - 1;
3072         u64 hole_start = (inode->i_size + mask) & ~mask;
3073         u64 block_end = (size + mask) & ~mask;
3074         u64 last_byte;
3075         u64 cur_offset;
3076         u64 hole_size;
3077         int err = 0;
3078
3079         if (size <= hole_start)
3080                 return 0;
3081
3082         btrfs_truncate_page(inode->i_mapping, inode->i_size);
3083
3084         while (1) {
3085                 struct btrfs_ordered_extent *ordered;
3086                 btrfs_wait_ordered_range(inode, hole_start,
3087                                          block_end - hole_start);
3088                 lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
3089                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3090                 if (!ordered)
3091                         break;
3092                 unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
3093                 btrfs_put_ordered_extent(ordered);
3094         }
3095
3096         trans = btrfs_start_transaction(root, 1);
3097         btrfs_set_trans_block_group(trans, inode);
3098
3099         cur_offset = hole_start;
3100         while (1) {
3101                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3102                                 block_end - cur_offset, 0);
3103                 BUG_ON(IS_ERR(em) || !em);
3104                 last_byte = min(extent_map_end(em), block_end);
3105                 last_byte = (last_byte + mask) & ~mask;
3106                 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
3107                         u64 hint_byte = 0;
3108                         hole_size = last_byte - cur_offset;
3109                         err = btrfs_drop_extents(trans, root, inode,
3110                                                  cur_offset,
3111                                                  cur_offset + hole_size,
3112                                                  block_end,
3113                                                  cur_offset, &hint_byte, 1);
3114                         if (err)
3115                                 break;
3116
3117                         err = btrfs_reserve_metadata_space(root, 1);
3118                         if (err)
3119                                 break;
3120
3121                         err = btrfs_insert_file_extent(trans, root,
3122                                         inode->i_ino, cur_offset, 0,
3123                                         0, hole_size, 0, hole_size,
3124                                         0, 0, 0);
3125                         btrfs_drop_extent_cache(inode, hole_start,
3126                                         last_byte - 1, 0);
3127                         btrfs_unreserve_metadata_space(root, 1);
3128                 }
3129                 free_extent_map(em);
3130                 cur_offset = last_byte;
3131                 if (err || cur_offset >= block_end)
3132                         break;
3133         }
3134
3135         btrfs_end_transaction(trans, root);
3136         unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
3137         return err;
3138 }
3139
3140 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3141 {
3142         struct inode *inode = dentry->d_inode;
3143         int err;
3144
3145         err = inode_change_ok(inode, attr);
3146         if (err)
3147                 return err;
3148
3149         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3150                 if (attr->ia_size > inode->i_size) {
3151                         err = btrfs_cont_expand(inode, attr->ia_size);
3152                         if (err)
3153                                 return err;
3154                 } else if (inode->i_size > 0 &&
3155                            attr->ia_size == 0) {
3156
3157                         /* we're truncating a file that used to have good
3158                          * data down to zero.  Make sure it gets into
3159                          * the ordered flush list so that any new writes
3160                          * get down to disk quickly.
3161                          */
3162                         BTRFS_I(inode)->ordered_data_close = 1;
3163                 }
3164         }
3165
3166         err = inode_setattr(inode, attr);
3167
3168         if (!err && ((attr->ia_valid & ATTR_MODE)))
3169                 err = btrfs_acl_chmod(inode);
3170         return err;
3171 }
3172
3173 void btrfs_delete_inode(struct inode *inode)
3174 {
3175         struct btrfs_trans_handle *trans;
3176         struct btrfs_root *root = BTRFS_I(inode)->root;
3177         unsigned long nr;
3178         int ret;
3179
3180         truncate_inode_pages(&inode->i_data, 0);
3181         if (is_bad_inode(inode)) {
3182                 btrfs_orphan_del(NULL, inode);
3183                 goto no_delete;
3184         }
3185         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3186
3187         if (inode->i_nlink > 0) {
3188                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3189                 goto no_delete;
3190         }
3191
3192         btrfs_i_size_write(inode, 0);
3193         trans = btrfs_join_transaction(root, 1);
3194
3195         btrfs_set_trans_block_group(trans, inode);
3196         ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size, 0);
3197         if (ret) {
3198                 btrfs_orphan_del(NULL, inode);
3199                 goto no_delete_lock;
3200         }
3201
3202         btrfs_orphan_del(trans, inode);
3203
3204         nr = trans->blocks_used;
3205         clear_inode(inode);
3206
3207         btrfs_end_transaction(trans, root);
3208         btrfs_btree_balance_dirty(root, nr);
3209         return;
3210
3211 no_delete_lock:
3212         nr = trans->blocks_used;
3213         btrfs_end_transaction(trans, root);
3214         btrfs_btree_balance_dirty(root, nr);
3215 no_delete:
3216         clear_inode(inode);
3217 }
3218
3219 /*
3220  * this returns the key found in the dir entry in the location pointer.
3221  * If no dir entries were found, location->objectid is 0.
3222  */
3223 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3224                                struct btrfs_key *location)
3225 {
3226         const char *name = dentry->d_name.name;
3227         int namelen = dentry->d_name.len;
3228         struct btrfs_dir_item *di;
3229         struct btrfs_path *path;
3230         struct btrfs_root *root = BTRFS_I(dir)->root;
3231         int ret = 0;
3232
3233         path = btrfs_alloc_path();
3234         BUG_ON(!path);
3235
3236         di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
3237                                     namelen, 0);
3238         if (IS_ERR(di))
3239                 ret = PTR_ERR(di);
3240
3241         if (!di || IS_ERR(di))
3242                 goto out_err;
3243
3244         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3245 out:
3246         btrfs_free_path(path);
3247         return ret;
3248 out_err:
3249         location->objectid = 0;
3250         goto out;
3251 }
3252
3253 /*
3254  * when we hit a tree root in a directory, the btrfs part of the inode
3255  * needs to be changed to reflect the root directory of the tree root.  This
3256  * is kind of like crossing a mount point.
3257  */
3258 static int fixup_tree_root_location(struct btrfs_root *root,
3259                                     struct inode *dir,
3260                                     struct dentry *dentry,
3261                                     struct btrfs_key *location,
3262                                     struct btrfs_root **sub_root)
3263 {
3264         struct btrfs_path *path;
3265         struct btrfs_root *new_root;
3266         struct btrfs_root_ref *ref;
3267         struct extent_buffer *leaf;
3268         int ret;
3269         int err = 0;
3270
3271         path = btrfs_alloc_path();
3272         if (!path) {
3273                 err = -ENOMEM;
3274                 goto out;
3275         }
3276
3277         err = -ENOENT;
3278         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3279                                   BTRFS_I(dir)->root->root_key.objectid,
3280                                   location->objectid);
3281         if (ret) {
3282                 if (ret < 0)
3283                         err = ret;
3284                 goto out;
3285         }
3286
3287         leaf = path->nodes[0];
3288         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3289         if (btrfs_root_ref_dirid(leaf, ref) != dir->i_ino ||
3290             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3291                 goto out;
3292
3293         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3294                                    (unsigned long)(ref + 1),
3295                                    dentry->d_name.len);
3296         if (ret)
3297                 goto out;
3298
3299         btrfs_release_path(root->fs_info->tree_root, path);
3300
3301         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3302         if (IS_ERR(new_root)) {
3303                 err = PTR_ERR(new_root);
3304                 goto out;
3305         }
3306
3307         if (btrfs_root_refs(&new_root->root_item) == 0) {
3308                 err = -ENOENT;
3309                 goto out;
3310         }
3311
3312         *sub_root = new_root;
3313         location->objectid = btrfs_root_dirid(&new_root->root_item);
3314         location->type = BTRFS_INODE_ITEM_KEY;
3315         location->offset = 0;
3316         err = 0;
3317 out:
3318         btrfs_free_path(path);
3319         return err;
3320 }
3321
3322 static void inode_tree_add(struct inode *inode)
3323 {
3324         struct btrfs_root *root = BTRFS_I(inode)->root;
3325         struct btrfs_inode *entry;
3326         struct rb_node **p;
3327         struct rb_node *parent;
3328 again:
3329         p = &root->inode_tree.rb_node;
3330         parent = NULL;
3331
3332         if (hlist_unhashed(&inode->i_hash))
3333                 return;
3334
3335         spin_lock(&root->inode_lock);
3336         while (*p) {
3337                 parent = *p;
3338                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3339
3340                 if (inode->i_ino < entry->vfs_inode.i_ino)
3341                         p = &parent->rb_left;
3342                 else if (inode->i_ino > entry->vfs_inode.i_ino)
3343                         p = &parent->rb_right;
3344                 else {
3345                         WARN_ON(!(entry->vfs_inode.i_state &
3346                                   (I_WILL_FREE | I_FREEING | I_CLEAR)));
3347                         rb_erase(parent, &root->inode_tree);
3348                         RB_CLEAR_NODE(parent);
3349                         spin_unlock(&root->inode_lock);
3350                         goto again;
3351                 }
3352         }
3353         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3354         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3355         spin_unlock(&root->inode_lock);
3356 }
3357
3358 static void inode_tree_del(struct inode *inode)
3359 {
3360         struct btrfs_root *root = BTRFS_I(inode)->root;
3361         int empty = 0;
3362
3363         spin_lock(&root->inode_lock);
3364         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3365                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3366                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3367                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3368         }
3369         spin_unlock(&root->inode_lock);
3370
3371         if (empty && btrfs_root_refs(&root->root_item) == 0) {
3372                 synchronize_srcu(&root->fs_info->subvol_srcu);
3373                 spin_lock(&root->inode_lock);
3374                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3375                 spin_unlock(&root->inode_lock);
3376                 if (empty)
3377                         btrfs_add_dead_root(root);
3378         }
3379 }
3380
3381 int btrfs_invalidate_inodes(struct btrfs_root *root)
3382 {
3383         struct rb_node *node;
3384         struct rb_node *prev;
3385         struct btrfs_inode *entry;
3386         struct inode *inode;
3387         u64 objectid = 0;
3388
3389         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3390
3391         spin_lock(&root->inode_lock);
3392 again:
3393         node = root->inode_tree.rb_node;
3394         prev = NULL;
3395         while (node) {
3396                 prev = node;
3397                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3398
3399                 if (objectid < entry->vfs_inode.i_ino)
3400                         node = node->rb_left;
3401                 else if (objectid > entry->vfs_inode.i_ino)
3402                         node = node->rb_right;
3403                 else
3404                         break;
3405         }
3406         if (!node) {
3407                 while (prev) {
3408                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
3409                         if (objectid <= entry->vfs_inode.i_ino) {
3410                                 node = prev;
3411                                 break;
3412                         }
3413                         prev = rb_next(prev);
3414                 }
3415         }
3416         while (node) {
3417                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3418                 objectid = entry->vfs_inode.i_ino + 1;
3419                 inode = igrab(&entry->vfs_inode);
3420                 if (inode) {
3421                         spin_unlock(&root->inode_lock);
3422                         if (atomic_read(&inode->i_count) > 1)
3423                                 d_prune_aliases(inode);
3424                         /*
3425                          * btrfs_drop_inode will remove it from
3426                          * the inode cache when its usage count
3427                          * hits zero.
3428                          */
3429                         iput(inode);
3430                         cond_resched();
3431                         spin_lock(&root->inode_lock);
3432                         goto again;
3433                 }
3434
3435                 if (cond_resched_lock(&root->inode_lock))
3436                         goto again;
3437
3438                 node = rb_next(node);
3439         }
3440         spin_unlock(&root->inode_lock);
3441         return 0;
3442 }
3443
3444 static noinline void init_btrfs_i(struct inode *inode)
3445 {
3446         struct btrfs_inode *bi = BTRFS_I(inode);
3447
3448         bi->generation = 0;
3449         bi->sequence = 0;
3450         bi->last_trans = 0;
3451         bi->logged_trans = 0;
3452         bi->delalloc_bytes = 0;
3453         bi->reserved_bytes = 0;
3454         bi->disk_i_size = 0;
3455         bi->flags = 0;
3456         bi->index_cnt = (u64)-1;
3457         bi->last_unlink_trans = 0;
3458         bi->ordered_data_close = 0;
3459         extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
3460         extent_io_tree_init(&BTRFS_I(inode)->io_tree,
3461                              inode->i_mapping, GFP_NOFS);
3462         extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
3463                              inode->i_mapping, GFP_NOFS);
3464         INIT_LIST_HEAD(&BTRFS_I(inode)->delalloc_inodes);
3465         INIT_LIST_HEAD(&BTRFS_I(inode)->ordered_operations);
3466         RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3467         btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
3468         mutex_init(&BTRFS_I(inode)->extent_mutex);
3469         mutex_init(&BTRFS_I(inode)->log_mutex);
3470 }
3471
3472 static int btrfs_init_locked_inode(struct inode *inode, void *p)
3473 {
3474         struct btrfs_iget_args *args = p;
3475         inode->i_ino = args->ino;
3476         init_btrfs_i(inode);
3477         BTRFS_I(inode)->root = args->root;
3478         btrfs_set_inode_space_info(args->root, inode);
3479         return 0;
3480 }
3481
3482 static int btrfs_find_actor(struct inode *inode, void *opaque)
3483 {
3484         struct btrfs_iget_args *args = opaque;
3485         return args->ino == inode->i_ino &&
3486                 args->root == BTRFS_I(inode)->root;
3487 }
3488
3489 static struct inode *btrfs_iget_locked(struct super_block *s,
3490                                        u64 objectid,
3491                                        struct btrfs_root *root)
3492 {
3493         struct inode *inode;
3494         struct btrfs_iget_args args;
3495         args.ino = objectid;
3496         args.root = root;
3497
3498         inode = iget5_locked(s, objectid, btrfs_find_actor,
3499                              btrfs_init_locked_inode,
3500                              (void *)&args);
3501         return inode;
3502 }
3503
3504 /* Get an inode object given its location and corresponding root.
3505  * Returns in *is_new if the inode was read from disk
3506  */
3507 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
3508                          struct btrfs_root *root)
3509 {
3510         struct inode *inode;
3511
3512         inode = btrfs_iget_locked(s, location->objectid, root);
3513         if (!inode)
3514                 return ERR_PTR(-ENOMEM);
3515
3516         if (inode->i_state & I_NEW) {
3517                 BTRFS_I(inode)->root = root;
3518                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
3519                 btrfs_read_locked_inode(inode);
3520
3521                 inode_tree_add(inode);
3522                 unlock_new_inode(inode);
3523         }
3524
3525         return inode;
3526 }
3527
3528 static struct inode *new_simple_dir(struct super_block *s,
3529                                     struct btrfs_key *key,
3530                                     struct btrfs_root *root)
3531 {
3532         struct inode *inode = new_inode(s);
3533
3534         if (!inode)
3535                 return ERR_PTR(-ENOMEM);
3536
3537         init_btrfs_i(inode);
3538
3539         BTRFS_I(inode)->root = root;
3540         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
3541         BTRFS_I(inode)->dummy_inode = 1;
3542
3543         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
3544         inode->i_op = &simple_dir_inode_operations;
3545         inode->i_fop = &simple_dir_operations;
3546         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
3547         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
3548
3549         return inode;
3550 }
3551
3552 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
3553 {
3554         struct inode *inode;
3555         struct btrfs_root *root = BTRFS_I(dir)->root;
3556         struct btrfs_root *sub_root = root;
3557         struct btrfs_key location;
3558         int index;
3559         int ret;
3560
3561         dentry->d_op = &btrfs_dentry_operations;
3562
3563         if (dentry->d_name.len > BTRFS_NAME_LEN)
3564                 return ERR_PTR(-ENAMETOOLONG);
3565
3566         ret = btrfs_inode_by_name(dir, dentry, &location);
3567
3568         if (ret < 0)
3569                 return ERR_PTR(ret);
3570
3571         if (location.objectid == 0)
3572                 return NULL;
3573
3574         if (location.type == BTRFS_INODE_ITEM_KEY) {
3575                 inode = btrfs_iget(dir->i_sb, &location, root);
3576                 return inode;
3577         }
3578
3579         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
3580
3581         index = srcu_read_lock(&root->fs_info->subvol_srcu);
3582         ret = fixup_tree_root_location(root, dir, dentry,
3583                                        &location, &sub_root);
3584         if (ret < 0) {
3585                 if (ret != -ENOENT)
3586                         inode = ERR_PTR(ret);
3587                 else
3588                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
3589         } else {
3590                 inode = btrfs_iget(dir->i_sb, &location, sub_root);
3591         }
3592         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
3593
3594         return inode;
3595 }
3596
3597 static int btrfs_dentry_delete(struct dentry *dentry)
3598 {
3599         struct btrfs_root *root;
3600
3601         if (!dentry->d_inode)
3602                 return 0;
3603
3604         root = BTRFS_I(dentry->d_inode)->root;
3605         if (btrfs_root_refs(&root->root_item) == 0)
3606                 return 1;
3607         return 0;
3608 }
3609
3610 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
3611                                    struct nameidata *nd)
3612 {
3613         struct inode *inode;
3614
3615         inode = btrfs_lookup_dentry(dir, dentry);
3616         if (IS_ERR(inode))
3617                 return ERR_CAST(inode);
3618
3619         return d_splice_alias(inode, dentry);
3620 }
3621
3622 static unsigned char btrfs_filetype_table[] = {
3623         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
3624 };
3625
3626 static int btrfs_real_readdir(struct file *filp, void *dirent,
3627                               filldir_t filldir)
3628 {
3629         struct inode *inode = filp->f_dentry->d_inode;
3630         struct btrfs_root *root = BTRFS_I(inode)->root;
3631         struct btrfs_item *item;
3632         struct btrfs_dir_item *di;
3633         struct btrfs_key key;
3634         struct btrfs_key found_key;
3635         struct btrfs_path *path;
3636         int ret;
3637         u32 nritems;
3638         struct extent_buffer *leaf;
3639         int slot;
3640         int advance;
3641         unsigned char d_type;
3642         int over = 0;
3643         u32 di_cur;
3644         u32 di_total;
3645         u32 di_len;
3646         int key_type = BTRFS_DIR_INDEX_KEY;
3647         char tmp_name[32];
3648         char *name_ptr;
3649         int name_len;
3650
3651         /* FIXME, use a real flag for deciding about the key type */
3652         if (root->fs_info->tree_root == root)
3653                 key_type = BTRFS_DIR_ITEM_KEY;
3654
3655         /* special case for "." */
3656         if (filp->f_pos == 0) {
3657                 over = filldir(dirent, ".", 1,
3658                                1, inode->i_ino,
3659                                DT_DIR);
3660                 if (over)
3661                         return 0;
3662                 filp->f_pos = 1;
3663         }
3664         /* special case for .., just use the back ref */
3665         if (filp->f_pos == 1) {
3666                 u64 pino = parent_ino(filp->f_path.dentry);
3667                 over = filldir(dirent, "..", 2,
3668                                2, pino, DT_DIR);
3669                 if (over)
3670                         return 0;
3671                 filp->f_pos = 2;
3672         }
3673         path = btrfs_alloc_path();
3674         path->reada = 2;
3675
3676         btrfs_set_key_type(&key, key_type);
3677         key.offset = filp->f_pos;
3678         key.objectid = inode->i_ino;
3679
3680         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3681         if (ret < 0)
3682                 goto err;
3683         advance = 0;
3684
3685         while (1) {
3686                 leaf = path->nodes[0];
3687                 nritems = btrfs_header_nritems(leaf);
3688                 slot = path->slots[0];
3689                 if (advance || slot >= nritems) {
3690                         if (slot >= nritems - 1) {
3691                                 ret = btrfs_next_leaf(root, path);
3692                                 if (ret)
3693                                         break;
3694                                 leaf = path->nodes[0];
3695                                 nritems = btrfs_header_nritems(leaf);
3696                                 slot = path->slots[0];
3697                         } else {
3698                                 slot++;
3699                                 path->slots[0]++;
3700                         }
3701                 }
3702
3703                 advance = 1;
3704                 item = btrfs_item_nr(leaf, slot);
3705                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3706
3707                 if (found_key.objectid != key.objectid)
3708                         break;
3709                 if (btrfs_key_type(&found_key) != key_type)
3710                         break;
3711                 if (found_key.offset < filp->f_pos)
3712                         continue;
3713
3714                 filp->f_pos = found_key.offset;
3715
3716                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
3717                 di_cur = 0;
3718                 di_total = btrfs_item_size(leaf, item);
3719
3720                 while (di_cur < di_total) {
3721                         struct btrfs_key location;
3722
3723                         name_len = btrfs_dir_name_len(leaf, di);
3724                         if (name_len <= sizeof(tmp_name)) {
3725                                 name_ptr = tmp_name;
3726                         } else {
3727                                 name_ptr = kmalloc(name_len, GFP_NOFS);
3728                                 if (!name_ptr) {
3729                                         ret = -ENOMEM;
3730                                         goto err;
3731                                 }
3732                         }
3733                         read_extent_buffer(leaf, name_ptr,
3734                                            (unsigned long)(di + 1), name_len);
3735
3736                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
3737                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
3738
3739                         /* is this a reference to our own snapshot? If so
3740                          * skip it
3741                          */
3742                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
3743                             location.objectid == root->root_key.objectid) {
3744                                 over = 0;
3745                                 goto skip;
3746                         }
3747                         over = filldir(dirent, name_ptr, name_len,
3748                                        found_key.offset, location.objectid,
3749                                        d_type);
3750
3751 skip:
3752                         if (name_ptr != tmp_name)
3753                                 kfree(name_ptr);
3754
3755                         if (over)
3756                                 goto nopos;
3757                         di_len = btrfs_dir_name_len(leaf, di) +
3758                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
3759                         di_cur += di_len;
3760                         di = (struct btrfs_dir_item *)((char *)di + di_len);
3761                 }
3762         }
3763
3764         /* Reached end of directory/root. Bump pos past the last item. */
3765         if (key_type == BTRFS_DIR_INDEX_KEY)
3766                 filp->f_pos = INT_LIMIT(off_t);
3767         else
3768                 filp->f_pos++;
3769 nopos:
3770         ret = 0;
3771 err:
3772         btrfs_free_path(path);
3773         return ret;
3774 }
3775
3776 int btrfs_write_inode(struct inode *inode, int wait)
3777 {
3778         struct btrfs_root *root = BTRFS_I(inode)->root;
3779         struct btrfs_trans_handle *trans;
3780         int ret = 0;
3781
3782         if (root->fs_info->btree_inode == inode)
3783                 return 0;
3784
3785         if (wait) {
3786                 trans = btrfs_join_transaction(root, 1);
3787                 btrfs_set_trans_block_group(trans, inode);
3788                 ret = btrfs_commit_transaction(trans, root);
3789         }
3790         return ret;
3791 }
3792
3793 /*
3794  * This is somewhat expensive, updating the tree every time the
3795  * inode changes.  But, it is most likely to find the inode in cache.
3796  * FIXME, needs more benchmarking...there are no reasons other than performance
3797  * to keep or drop this code.
3798  */
3799 void btrfs_dirty_inode(struct inode *inode)
3800 {
3801         struct btrfs_root *root = BTRFS_I(inode)->root;
3802         struct btrfs_trans_handle *trans;
3803
3804         trans = btrfs_join_transaction(root, 1);
3805         btrfs_set_trans_block_group(trans, inode);
3806         btrfs_update_inode(trans, root, inode);
3807         btrfs_end_transaction(trans, root);
3808 }
3809
3810 /*
3811  * find the highest existing sequence number in a directory
3812  * and then set the in-memory index_cnt variable to reflect
3813  * free sequence numbers
3814  */
3815 static int btrfs_set_inode_index_count(struct inode *inode)
3816 {
3817         struct btrfs_root *root = BTRFS_I(inode)->root;
3818         struct btrfs_key key, found_key;
3819         struct btrfs_path *path;
3820         struct extent_buffer *leaf;
3821         int ret;
3822
3823         key.objectid = inode->i_ino;
3824         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
3825         key.offset = (u64)-1;
3826
3827         path = btrfs_alloc_path();
3828         if (!path)
3829                 return -ENOMEM;
3830
3831         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3832         if (ret < 0)
3833                 goto out;
3834         /* FIXME: we should be able to handle this */
3835         if (ret == 0)
3836                 goto out;
3837         ret = 0;
3838
3839         /*
3840          * MAGIC NUMBER EXPLANATION:
3841          * since we search a directory based on f_pos we have to start at 2
3842          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
3843          * else has to start at 2
3844          */
3845         if (path->slots[0] == 0) {
3846                 BTRFS_I(inode)->index_cnt = 2;
3847                 goto out;
3848         }
3849
3850         path->slots[0]--;
3851
3852         leaf = path->nodes[0];
3853         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3854
3855         if (found_key.objectid != inode->i_ino ||
3856             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
3857                 BTRFS_I(inode)->index_cnt = 2;
3858                 goto out;
3859         }
3860
3861         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
3862 out:
3863         btrfs_free_path(path);
3864         return ret;
3865 }
3866
3867 /*
3868  * helper to find a free sequence number in a given directory.  This current
3869  * code is very simple, later versions will do smarter things in the btree
3870  */
3871 int btrfs_set_inode_index(struct inode *dir, u64 *index)
3872 {
3873         int ret = 0;
3874
3875         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
3876                 ret = btrfs_set_inode_index_count(dir);
3877                 if (ret)
3878                         return ret;
3879         }
3880
3881         *index = BTRFS_I(dir)->index_cnt;
3882         BTRFS_I(dir)->index_cnt++;
3883
3884         return ret;
3885 }
3886
3887 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
3888                                      struct btrfs_root *root,
3889                                      struct inode *dir,
3890                                      const char *name, int name_len,
3891                                      u64 ref_objectid, u64 objectid,
3892                                      u64 alloc_hint, int mode, u64 *index)
3893 {
3894         struct inode *inode;
3895         struct btrfs_inode_item *inode_item;
3896         struct btrfs_key *location;
3897         struct btrfs_path *path;
3898         struct btrfs_inode_ref *ref;
3899         struct btrfs_key key[2];
3900         u32 sizes[2];
3901         unsigned long ptr;
3902         int ret;
3903         int owner;
3904
3905         path = btrfs_alloc_path();
3906         BUG_ON(!path);
3907
3908         inode = new_inode(root->fs_info->sb);
3909         if (!inode)
3910                 return ERR_PTR(-ENOMEM);
3911
3912         if (dir) {
3913                 ret = btrfs_set_inode_index(dir, index);
3914                 if (ret) {
3915                         iput(inode);
3916                         return ERR_PTR(ret);
3917                 }
3918         }
3919         /*
3920          * index_cnt is ignored for everything but a dir,
3921          * btrfs_get_inode_index_count has an explanation for the magic
3922          * number
3923          */
3924         init_btrfs_i(inode);
3925         BTRFS_I(inode)->index_cnt = 2;
3926         BTRFS_I(inode)->root = root;
3927         BTRFS_I(inode)->generation = trans->transid;
3928         btrfs_set_inode_space_info(root, inode);
3929
3930         if (mode & S_IFDIR)
3931                 owner = 0;
3932         else
3933                 owner = 1;
3934         BTRFS_I(inode)->block_group =
3935                         btrfs_find_block_group(root, 0, alloc_hint, owner);
3936
3937         key[0].objectid = objectid;
3938         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
3939         key[0].offset = 0;
3940
3941         key[1].objectid = objectid;
3942         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
3943         key[1].offset = ref_objectid;
3944
3945         sizes[0] = sizeof(struct btrfs_inode_item);
3946         sizes[1] = name_len + sizeof(*ref);
3947
3948         path->leave_spinning = 1;
3949         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
3950         if (ret != 0)
3951                 goto fail;
3952
3953         inode->i_uid = current_fsuid();
3954
3955         if (dir && (dir->i_mode & S_ISGID)) {
3956                 inode->i_gid = dir->i_gid;
3957                 if (S_ISDIR(mode))
3958                         mode |= S_ISGID;
3959         } else
3960                 inode->i_gid = current_fsgid();
3961
3962         inode->i_mode = mode;
3963         inode->i_ino = objectid;
3964         inode_set_bytes(inode, 0);
3965         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
3966         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3967                                   struct btrfs_inode_item);
3968         fill_inode_item(trans, path->nodes[0], inode_item, inode);
3969
3970         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
3971                              struct btrfs_inode_ref);
3972         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
3973         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
3974         ptr = (unsigned long)(ref + 1);
3975         write_extent_buffer(path->nodes[0], name, ptr, name_len);
3976
3977         btrfs_mark_buffer_dirty(path->nodes[0]);
3978         btrfs_free_path(path);
3979
3980         location = &BTRFS_I(inode)->location;
3981         location->objectid = objectid;
3982         location->offset = 0;
3983         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
3984
3985         btrfs_inherit_iflags(inode, dir);
3986
3987         if ((mode & S_IFREG)) {
3988                 if (btrfs_test_opt(root, NODATASUM))
3989                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
3990                 if (btrfs_test_opt(root, NODATACOW))
3991                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
3992         }
3993
3994         insert_inode_hash(inode);
3995         inode_tree_add(inode);
3996         return inode;
3997 fail:
3998         if (dir)
3999                 BTRFS_I(dir)->index_cnt--;
4000         btrfs_free_path(path);
4001         iput(inode);
4002         return ERR_PTR(ret);
4003 }
4004
4005 static inline u8 btrfs_inode_type(struct inode *inode)
4006 {
4007         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4008 }
4009
4010 /*
4011  * utility function to add 'inode' into 'parent_inode' with
4012  * a give name and a given sequence number.
4013  * if 'add_backref' is true, also insert a backref from the
4014  * inode to the parent directory.
4015  */
4016 int btrfs_add_link(struct btrfs_trans_handle *trans,
4017                    struct inode *parent_inode, struct inode *inode,
4018                    const char *name, int name_len, int add_backref, u64 index)
4019 {
4020         int ret = 0;
4021         struct btrfs_key key;
4022         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4023
4024         if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
4025                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4026         } else {
4027                 key.objectid = inode->i_ino;
4028                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4029                 key.offset = 0;
4030         }
4031
4032         if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
4033                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4034                                          key.objectid, root->root_key.objectid,
4035                                          parent_inode->i_ino,
4036                                          index, name, name_len);
4037         } else if (add_backref) {
4038                 ret = btrfs_insert_inode_ref(trans, root,
4039                                              name, name_len, inode->i_ino,
4040                                              parent_inode->i_ino, index);
4041         }
4042
4043         if (ret == 0) {
4044                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4045                                             parent_inode->i_ino, &key,
4046                                             btrfs_inode_type(inode), index);
4047                 BUG_ON(ret);
4048
4049                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4050                                    name_len * 2);
4051                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4052                 ret = btrfs_update_inode(trans, root, parent_inode);
4053         }
4054         return ret;
4055 }
4056
4057 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4058                             struct dentry *dentry, struct inode *inode,
4059                             int backref, u64 index)
4060 {
4061         int err = btrfs_add_link(trans, dentry->d_parent->d_inode,
4062                                  inode, dentry->d_name.name,
4063                                  dentry->d_name.len, backref, index);
4064         if (!err) {
4065                 d_instantiate(dentry, inode);
4066                 return 0;
4067         }
4068         if (err > 0)
4069                 err = -EEXIST;
4070         return err;
4071 }
4072
4073 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4074                         int mode, dev_t rdev)
4075 {
4076         struct btrfs_trans_handle *trans;
4077         struct btrfs_root *root = BTRFS_I(dir)->root;
4078         struct inode *inode = NULL;
4079         int err;
4080         int drop_inode = 0;
4081         u64 objectid;
4082         unsigned long nr = 0;
4083         u64 index = 0;
4084
4085         if (!new_valid_dev(rdev))
4086                 return -EINVAL;
4087
4088         /*
4089          * 2 for inode item and ref
4090          * 2 for dir items
4091          * 1 for xattr if selinux is on
4092          */
4093         err = btrfs_reserve_metadata_space(root, 5);
4094         if (err)
4095                 return err;
4096
4097         trans = btrfs_start_transaction(root, 1);
4098         if (!trans)
4099                 goto fail;
4100         btrfs_set_trans_block_group(trans, dir);
4101
4102         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
4103         if (err) {
4104                 err = -ENOSPC;
4105                 goto out_unlock;
4106         }
4107
4108         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4109                                 dentry->d_name.len,
4110                                 dentry->d_parent->d_inode->i_ino, objectid,
4111                                 BTRFS_I(dir)->block_group, mode, &index);
4112         err = PTR_ERR(inode);
4113         if (IS_ERR(inode))
4114                 goto out_unlock;
4115
4116         err = btrfs_init_inode_security(inode, dir);
4117         if (err) {
4118                 drop_inode = 1;
4119                 goto out_unlock;
4120         }
4121
4122         btrfs_set_trans_block_group(trans, inode);
4123         err = btrfs_add_nondir(trans, dentry, inode, 0, index);
4124         if (err)
4125                 drop_inode = 1;
4126         else {
4127                 inode->i_op = &btrfs_special_inode_operations;
4128                 init_special_inode(inode, inode->i_mode, rdev);
4129                 btrfs_update_inode(trans, root, inode);
4130         }
4131         btrfs_update_inode_block_group(trans, inode);
4132         btrfs_update_inode_block_group(trans, dir);
4133 out_unlock:
4134         nr = trans->blocks_used;
4135         btrfs_end_transaction_throttle(trans, root);
4136 fail:
4137         btrfs_unreserve_metadata_space(root, 5);
4138         if (drop_inode) {
4139                 inode_dec_link_count(inode);
4140                 iput(inode);
4141         }
4142         btrfs_btree_balance_dirty(root, nr);
4143         return err;
4144 }
4145
4146 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4147                         int mode, struct nameidata *nd)
4148 {
4149         struct btrfs_trans_handle *trans;
4150         struct btrfs_root *root = BTRFS_I(dir)->root;
4151         struct inode *inode = NULL;
4152         int err;
4153         int drop_inode = 0;
4154         unsigned long nr = 0;
4155         u64 objectid;
4156         u64 index = 0;
4157
4158         /*
4159          * 2 for inode item and ref
4160          * 2 for dir items
4161          * 1 for xattr if selinux is on
4162          */
4163         err = btrfs_reserve_metadata_space(root, 5);
4164         if (err)
4165                 return err;
4166
4167         trans = btrfs_start_transaction(root, 1);
4168         if (!trans)
4169                 goto fail;
4170         btrfs_set_trans_block_group(trans, dir);
4171
4172         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
4173         if (err) {
4174                 err = -ENOSPC;
4175                 goto out_unlock;
4176         }
4177
4178         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4179                                 dentry->d_name.len,
4180                                 dentry->d_parent->d_inode->i_ino,
4181                                 objectid, BTRFS_I(dir)->block_group, mode,
4182                                 &index);
4183         err = PTR_ERR(inode);
4184         if (IS_ERR(inode))
4185                 goto out_unlock;
4186
4187         err = btrfs_init_inode_security(inode, dir);
4188         if (err) {
4189                 drop_inode = 1;
4190                 goto out_unlock;
4191         }
4192
4193         btrfs_set_trans_block_group(trans, inode);
4194         err = btrfs_add_nondir(trans, dentry, inode, 0, index);
4195         if (err)
4196                 drop_inode = 1;
4197         else {
4198                 inode->i_mapping->a_ops = &btrfs_aops;
4199                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4200                 inode->i_fop = &btrfs_file_operations;
4201                 inode->i_op = &btrfs_file_inode_operations;
4202                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4203         }
4204         btrfs_update_inode_block_group(trans, inode);
4205         btrfs_update_inode_block_group(trans, dir);
4206 out_unlock:
4207         nr = trans->blocks_used;
4208         btrfs_end_transaction_throttle(trans, root);
4209 fail:
4210         btrfs_unreserve_metadata_space(root, 5);
4211         if (drop_inode) {
4212                 inode_dec_link_count(inode);
4213                 iput(inode);
4214         }
4215         btrfs_btree_balance_dirty(root, nr);
4216         return err;
4217 }
4218
4219 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4220                       struct dentry *dentry)
4221 {
4222         struct btrfs_trans_handle *trans;
4223         struct btrfs_root *root = BTRFS_I(dir)->root;
4224         struct inode *inode = old_dentry->d_inode;
4225         u64 index;
4226         unsigned long nr = 0;
4227         int err;
4228         int drop_inode = 0;
4229
4230         if (inode->i_nlink == 0)
4231                 return -ENOENT;
4232
4233         /*
4234          * 1 item for inode ref
4235          * 2 items for dir items
4236          */
4237         err = btrfs_reserve_metadata_space(root, 3);
4238         if (err)
4239                 return err;
4240
4241         btrfs_inc_nlink(inode);
4242
4243         err = btrfs_set_inode_index(dir, &index);
4244         if (err)
4245                 goto fail;
4246
4247         trans = btrfs_start_transaction(root, 1);
4248
4249         btrfs_set_trans_block_group(trans, dir);
4250         atomic_inc(&inode->i_count);
4251
4252         err = btrfs_add_nondir(trans, dentry, inode, 1, index);
4253
4254         if (err) {
4255                 drop_inode = 1;
4256         } else {
4257                 btrfs_update_inode_block_group(trans, dir);
4258                 err = btrfs_update_inode(trans, root, inode);
4259                 BUG_ON(err);
4260                 btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
4261         }
4262
4263         nr = trans->blocks_used;
4264         btrfs_end_transaction_throttle(trans, root);
4265 fail:
4266         btrfs_unreserve_metadata_space(root, 3);
4267         if (drop_inode) {
4268                 inode_dec_link_count(inode);
4269                 iput(inode);
4270         }
4271         btrfs_btree_balance_dirty(root, nr);
4272         return err;
4273 }
4274
4275 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4276 {
4277         struct inode *inode = NULL;
4278         struct btrfs_trans_handle *trans;
4279         struct btrfs_root *root = BTRFS_I(dir)->root;
4280         int err = 0;
4281         int drop_on_err = 0;
4282         u64 objectid = 0;
4283         u64 index = 0;
4284         unsigned long nr = 1;
4285
4286         /*
4287          * 2 items for inode and ref
4288          * 2 items for dir items
4289          * 1 for xattr if selinux is on
4290          */
4291         err = btrfs_reserve_metadata_space(root, 5);
4292         if (err)
4293                 return err;
4294
4295         trans = btrfs_start_transaction(root, 1);
4296         if (!trans) {
4297                 err = -ENOMEM;
4298                 goto out_unlock;
4299         }
4300         btrfs_set_trans_block_group(trans, dir);
4301
4302         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
4303         if (err) {
4304                 err = -ENOSPC;
4305                 goto out_unlock;
4306         }
4307
4308         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4309                                 dentry->d_name.len,
4310                                 dentry->d_parent->d_inode->i_ino, objectid,
4311                                 BTRFS_I(dir)->block_group, S_IFDIR | mode,
4312                                 &index);
4313         if (IS_ERR(inode)) {
4314                 err = PTR_ERR(inode);
4315                 goto out_fail;
4316         }
4317
4318         drop_on_err = 1;
4319
4320         err = btrfs_init_inode_security(inode, dir);
4321         if (err)
4322                 goto out_fail;
4323
4324         inode->i_op = &btrfs_dir_inode_operations;
4325         inode->i_fop = &btrfs_dir_file_operations;
4326         btrfs_set_trans_block_group(trans, inode);
4327
4328         btrfs_i_size_write(inode, 0);
4329         err = btrfs_update_inode(trans, root, inode);
4330         if (err)
4331                 goto out_fail;
4332
4333         err = btrfs_add_link(trans, dentry->d_parent->d_inode,
4334                                  inode, dentry->d_name.name,
4335                                  dentry->d_name.len, 0, index);
4336         if (err)
4337                 goto out_fail;
4338
4339         d_instantiate(dentry, inode);
4340         drop_on_err = 0;
4341         btrfs_update_inode_block_group(trans, inode);
4342         btrfs_update_inode_block_group(trans, dir);
4343
4344 out_fail:
4345         nr = trans->blocks_used;
4346         btrfs_end_transaction_throttle(trans, root);
4347
4348 out_unlock:
4349         btrfs_unreserve_metadata_space(root, 5);
4350         if (drop_on_err)
4351                 iput(inode);
4352         btrfs_btree_balance_dirty(root, nr);
4353         return err;
4354 }
4355
4356 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4357  * and an extent that you want to insert, deal with overlap and insert
4358  * the new extent into the tree.
4359  */
4360 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4361                                 struct extent_map *existing,
4362                                 struct extent_map *em,
4363                                 u64 map_start, u64 map_len)
4364 {
4365         u64 start_diff;
4366
4367         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4368         start_diff = map_start - em->start;
4369         em->start = map_start;
4370         em->len = map_len;
4371         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4372             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4373                 em->block_start += start_diff;
4374                 em->block_len -= start_diff;
4375         }
4376         return add_extent_mapping(em_tree, em);
4377 }
4378
4379 static noinline int uncompress_inline(struct btrfs_path *path,
4380                                       struct inode *inode, struct page *page,
4381                                       size_t pg_offset, u64 extent_offset,
4382                                       struct btrfs_file_extent_item *item)
4383 {
4384         int ret;
4385         struct extent_buffer *leaf = path->nodes[0];
4386         char *tmp;
4387         size_t max_size;
4388         unsigned long inline_size;
4389         unsigned long ptr;
4390
4391         WARN_ON(pg_offset != 0);
4392         max_size = btrfs_file_extent_ram_bytes(leaf, item);
4393         inline_size = btrfs_file_extent_inline_item_len(leaf,
4394                                         btrfs_item_nr(leaf, path->slots[0]));
4395         tmp = kmalloc(inline_size, GFP_NOFS);
4396         ptr = btrfs_file_extent_inline_start(item);
4397
4398         read_extent_buffer(leaf, tmp, ptr, inline_size);
4399
4400         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
4401         ret = btrfs_zlib_decompress(tmp, page, extent_offset,
4402                                     inline_size, max_size);
4403         if (ret) {
4404                 char *kaddr = kmap_atomic(page, KM_USER0);
4405                 unsigned long copy_size = min_t(u64,
4406                                   PAGE_CACHE_SIZE - pg_offset,
4407                                   max_size - extent_offset);
4408                 memset(kaddr + pg_offset, 0, copy_size);
4409                 kunmap_atomic(kaddr, KM_USER0);
4410         }
4411         kfree(tmp);
4412         return 0;
4413 }
4414
4415 /*
4416  * a bit scary, this does extent mapping from logical file offset to the disk.
4417  * the ugly parts come from merging extents from the disk with the in-ram
4418  * representation.  This gets more complex because of the data=ordered code,
4419  * where the in-ram extents might be locked pending data=ordered completion.
4420  *
4421  * This also copies inline extents directly into the page.
4422  */
4423
4424 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
4425                                     size_t pg_offset, u64 start, u64 len,
4426                                     int create)
4427 {
4428         int ret;
4429         int err = 0;
4430         u64 bytenr;
4431         u64 extent_start = 0;
4432         u64 extent_end = 0;
4433         u64 objectid = inode->i_ino;
4434         u32 found_type;
4435         struct btrfs_path *path = NULL;
4436         struct btrfs_root *root = BTRFS_I(inode)->root;
4437         struct btrfs_file_extent_item *item;
4438         struct extent_buffer *leaf;
4439         struct btrfs_key found_key;
4440         struct extent_map *em = NULL;
4441         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4442         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4443         struct btrfs_trans_handle *trans = NULL;
4444         int compressed;
4445
4446 again:
4447         read_lock(&em_tree->lock);
4448         em = lookup_extent_mapping(em_tree, start, len);
4449         if (em)
4450                 em->bdev = root->fs_info->fs_devices->latest_bdev;
4451         read_unlock(&em_tree->lock);
4452
4453         if (em) {
4454                 if (em->start > start || em->start + em->len <= start)
4455                         free_extent_map(em);
4456                 else if (em->block_start == EXTENT_MAP_INLINE && page)
4457                         free_extent_map(em);
4458                 else
4459                         goto out;
4460         }
4461         em = alloc_extent_map(GFP_NOFS);
4462         if (!em) {
4463                 err = -ENOMEM;
4464                 goto out;
4465         }
4466         em->bdev = root->fs_info->fs_devices->latest_bdev;
4467         em->start = EXTENT_MAP_HOLE;
4468         em->orig_start = EXTENT_MAP_HOLE;
4469         em->len = (u64)-1;
4470         em->block_len = (u64)-1;
4471
4472         if (!path) {
4473                 path = btrfs_alloc_path();
4474                 BUG_ON(!path);
4475         }
4476
4477         ret = btrfs_lookup_file_extent(trans, root, path,
4478                                        objectid, start, trans != NULL);
4479         if (ret < 0) {
4480                 err = ret;
4481                 goto out;
4482         }
4483
4484         if (ret != 0) {
4485                 if (path->slots[0] == 0)
4486                         goto not_found;
4487                 path->slots[0]--;
4488         }
4489
4490         leaf = path->nodes[0];
4491         item = btrfs_item_ptr(leaf, path->slots[0],
4492                               struct btrfs_file_extent_item);
4493         /* are we inside the extent that was found? */
4494         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4495         found_type = btrfs_key_type(&found_key);
4496         if (found_key.objectid != objectid ||
4497             found_type != BTRFS_EXTENT_DATA_KEY) {
4498                 goto not_found;
4499         }
4500
4501         found_type = btrfs_file_extent_type(leaf, item);
4502         extent_start = found_key.offset;
4503         compressed = btrfs_file_extent_compression(leaf, item);
4504         if (found_type == BTRFS_FILE_EXTENT_REG ||
4505             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
4506                 extent_end = extent_start +
4507                        btrfs_file_extent_num_bytes(leaf, item);
4508         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
4509                 size_t size;
4510                 size = btrfs_file_extent_inline_len(leaf, item);
4511                 extent_end = (extent_start + size + root->sectorsize - 1) &
4512                         ~((u64)root->sectorsize - 1);
4513         }
4514
4515         if (start >= extent_end) {
4516                 path->slots[0]++;
4517                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
4518                         ret = btrfs_next_leaf(root, path);
4519                         if (ret < 0) {
4520                                 err = ret;
4521                                 goto out;
4522                         }
4523                         if (ret > 0)
4524                                 goto not_found;
4525                         leaf = path->nodes[0];
4526                 }
4527                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4528                 if (found_key.objectid != objectid ||
4529                     found_key.type != BTRFS_EXTENT_DATA_KEY)
4530                         goto not_found;
4531                 if (start + len <= found_key.offset)
4532                         goto not_found;
4533                 em->start = start;
4534                 em->len = found_key.offset - start;
4535                 goto not_found_em;
4536         }
4537
4538         if (found_type == BTRFS_FILE_EXTENT_REG ||
4539             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
4540                 em->start = extent_start;
4541                 em->len = extent_end - extent_start;
4542                 em->orig_start = extent_start -
4543                                  btrfs_file_extent_offset(leaf, item);
4544                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
4545                 if (bytenr == 0) {
4546                         em->block_start = EXTENT_MAP_HOLE;
4547                         goto insert;
4548                 }
4549                 if (compressed) {
4550                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
4551                         em->block_start = bytenr;
4552                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
4553                                                                          item);
4554                 } else {
4555                         bytenr += btrfs_file_extent_offset(leaf, item);
4556                         em->block_start = bytenr;
4557                         em->block_len = em->len;
4558                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
4559                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
4560                 }
4561                 goto insert;
4562         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
4563                 unsigned long ptr;
4564                 char *map;
4565                 size_t size;
4566                 size_t extent_offset;
4567                 size_t copy_size;
4568
4569                 em->block_start = EXTENT_MAP_INLINE;
4570                 if (!page || create) {
4571                         em->start = extent_start;
4572                         em->len = extent_end - extent_start;
4573                         goto out;
4574                 }
4575
4576                 size = btrfs_file_extent_inline_len(leaf, item);
4577                 extent_offset = page_offset(page) + pg_offset - extent_start;
4578                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
4579                                 size - extent_offset);
4580                 em->start = extent_start + extent_offset;
4581                 em->len = (copy_size + root->sectorsize - 1) &
4582                         ~((u64)root->sectorsize - 1);
4583                 em->orig_start = EXTENT_MAP_INLINE;
4584                 if (compressed)
4585                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
4586                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
4587                 if (create == 0 && !PageUptodate(page)) {
4588                         if (btrfs_file_extent_compression(leaf, item) ==
4589                             BTRFS_COMPRESS_ZLIB) {
4590                                 ret = uncompress_inline(path, inode, page,
4591                                                         pg_offset,
4592                                                         extent_offset, item);
4593                                 BUG_ON(ret);
4594                         } else {
4595                                 map = kmap(page);
4596                                 read_extent_buffer(leaf, map + pg_offset, ptr,
4597                                                    copy_size);
4598                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
4599                                         memset(map + pg_offset + copy_size, 0,
4600                                                PAGE_CACHE_SIZE - pg_offset -
4601                                                copy_size);
4602                                 }
4603                                 kunmap(page);
4604                         }
4605                         flush_dcache_page(page);
4606                 } else if (create && PageUptodate(page)) {
4607                         if (!trans) {
4608                                 kunmap(page);
4609                                 free_extent_map(em);
4610                                 em = NULL;
4611                                 btrfs_release_path(root, path);
4612                                 trans = btrfs_join_transaction(root, 1);
4613                                 goto again;
4614                         }
4615                         map = kmap(page);
4616                         write_extent_buffer(leaf, map + pg_offset, ptr,
4617                                             copy_size);
4618                         kunmap(page);
4619                         btrfs_mark_buffer_dirty(leaf);
4620                 }
4621                 set_extent_uptodate(io_tree, em->start,
4622                                     extent_map_end(em) - 1, GFP_NOFS);
4623                 goto insert;
4624         } else {
4625                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
4626                 WARN_ON(1);
4627         }
4628 not_found:
4629         em->start = start;
4630         em->len = len;
4631 not_found_em:
4632         em->block_start = EXTENT_MAP_HOLE;
4633         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
4634 insert:
4635         btrfs_release_path(root, path);
4636         if (em->start > start || extent_map_end(em) <= start) {
4637                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
4638                        "[%llu %llu]\n", (unsigned long long)em->start,
4639                        (unsigned long long)em->len,
4640                        (unsigned long long)start,
4641                        (unsigned long long)len);
4642                 err = -EIO;
4643                 goto out;
4644         }
4645
4646         err = 0;
4647         write_lock(&em_tree->lock);
4648         ret = add_extent_mapping(em_tree, em);
4649         /* it is possible that someone inserted the extent into the tree
4650          * while we had the lock dropped.  It is also possible that
4651          * an overlapping map exists in the tree
4652          */
4653         if (ret == -EEXIST) {
4654                 struct extent_map *existing;
4655
4656                 ret = 0;
4657
4658                 existing = lookup_extent_mapping(em_tree, start, len);
4659                 if (existing && (existing->start > start ||
4660                     existing->start + existing->len <= start)) {
4661                         free_extent_map(existing);
4662                         existing = NULL;
4663                 }
4664                 if (!existing) {
4665                         existing = lookup_extent_mapping(em_tree, em->start,
4666                                                          em->len);
4667                         if (existing) {
4668                                 err = merge_extent_mapping(em_tree, existing,
4669                                                            em, start,
4670                                                            root->sectorsize);
4671                                 free_extent_map(existing);
4672                                 if (err) {
4673                                         free_extent_map(em);
4674                                         em = NULL;
4675                                 }
4676                         } else {
4677                                 err = -EIO;
4678                                 free_extent_map(em);
4679                                 em = NULL;
4680                         }
4681                 } else {
4682                         free_extent_map(em);
4683                         em = existing;
4684                         err = 0;
4685                 }
4686         }
4687         write_unlock(&em_tree->lock);
4688 out:
4689         if (path)
4690                 btrfs_free_path(path);
4691         if (trans) {
4692                 ret = btrfs_end_transaction(trans, root);
4693                 if (!err)
4694                         err = ret;
4695         }
4696         if (err) {
4697                 free_extent_map(em);
4698                 return ERR_PTR(err);
4699         }
4700         return em;
4701 }
4702
4703 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
4704                         const struct iovec *iov, loff_t offset,
4705                         unsigned long nr_segs)
4706 {
4707         return -EINVAL;
4708 }
4709
4710 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4711                 __u64 start, __u64 len)
4712 {
4713         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent);
4714 }
4715
4716 int btrfs_readpage(struct file *file, struct page *page)
4717 {
4718         struct extent_io_tree *tree;
4719         tree = &BTRFS_I(page->mapping->host)->io_tree;
4720         return extent_read_full_page(tree, page, btrfs_get_extent);
4721 }
4722
4723 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
4724 {
4725         struct extent_io_tree *tree;
4726
4727
4728         if (current->flags & PF_MEMALLOC) {
4729                 redirty_page_for_writepage(wbc, page);
4730                 unlock_page(page);
4731                 return 0;
4732         }
4733         tree = &BTRFS_I(page->mapping->host)->io_tree;
4734         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
4735 }
4736
4737 int btrfs_writepages(struct address_space *mapping,
4738                      struct writeback_control *wbc)
4739 {
4740         struct extent_io_tree *tree;
4741
4742         tree = &BTRFS_I(mapping->host)->io_tree;
4743         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
4744 }
4745
4746 static int
4747 btrfs_readpages(struct file *file, struct address_space *mapping,
4748                 struct list_head *pages, unsigned nr_pages)
4749 {
4750         struct extent_io_tree *tree;
4751         tree = &BTRFS_I(mapping->host)->io_tree;
4752         return extent_readpages(tree, mapping, pages, nr_pages,
4753                                 btrfs_get_extent);
4754 }
4755 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
4756 {
4757         struct extent_io_tree *tree;
4758         struct extent_map_tree *map;
4759         int ret;
4760
4761         tree = &BTRFS_I(page->mapping->host)->io_tree;
4762         map = &BTRFS_I(page->mapping->host)->extent_tree;
4763         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
4764         if (ret == 1) {
4765                 ClearPagePrivate(page);
4766                 set_page_private(page, 0);
4767                 page_cache_release(page);
4768         }
4769         return ret;
4770 }
4771
4772 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
4773 {
4774         if (PageWriteback(page) || PageDirty(page))
4775                 return 0;
4776         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
4777 }
4778
4779 static void btrfs_invalidatepage(struct page *page, unsigned long offset)
4780 {
4781         struct extent_io_tree *tree;
4782         struct btrfs_ordered_extent *ordered;
4783         u64 page_start = page_offset(page);
4784         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
4785
4786
4787         /*
4788          * we have the page locked, so new writeback can't start,
4789          * and the dirty bit won't be cleared while we are here.
4790          *
4791          * Wait for IO on this page so that we can safely clear
4792          * the PagePrivate2 bit and do ordered accounting
4793          */
4794         wait_on_page_writeback(page);
4795
4796         tree = &BTRFS_I(page->mapping->host)->io_tree;
4797         if (offset) {
4798                 btrfs_releasepage(page, GFP_NOFS);
4799                 return;
4800         }
4801         lock_extent(tree, page_start, page_end, GFP_NOFS);
4802         ordered = btrfs_lookup_ordered_extent(page->mapping->host,
4803                                            page_offset(page));
4804         if (ordered) {
4805                 /*
4806                  * IO on this page will never be started, so we need
4807                  * to account for any ordered extents now
4808                  */
4809                 clear_extent_bit(tree, page_start, page_end,
4810                                  EXTENT_DIRTY | EXTENT_DELALLOC |
4811                                  EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
4812                 /*
4813                  * whoever cleared the private bit is responsible
4814                  * for the finish_ordered_io
4815                  */
4816                 if (TestClearPagePrivate2(page)) {
4817                         btrfs_finish_ordered_io(page->mapping->host,
4818                                                 page_start, page_end);
4819                 }
4820                 btrfs_put_ordered_extent(ordered);
4821                 lock_extent(tree, page_start, page_end, GFP_NOFS);
4822         }
4823         clear_extent_bit(tree, page_start, page_end,
4824                  EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
4825                  1, 1, NULL, GFP_NOFS);
4826         __btrfs_releasepage(page, GFP_NOFS);
4827
4828         ClearPageChecked(page);
4829         if (PagePrivate(page)) {
4830                 ClearPagePrivate(page);
4831                 set_page_private(page, 0);
4832                 page_cache_release(page);
4833         }
4834 }
4835
4836 /*
4837  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
4838  * called from a page fault handler when a page is first dirtied. Hence we must
4839  * be careful to check for EOF conditions here. We set the page up correctly
4840  * for a written page which means we get ENOSPC checking when writing into
4841  * holes and correct delalloc and unwritten extent mapping on filesystems that
4842  * support these features.
4843  *
4844  * We are not allowed to take the i_mutex here so we have to play games to
4845  * protect against truncate races as the page could now be beyond EOF.  Because
4846  * vmtruncate() writes the inode size before removing pages, once we have the
4847  * page lock we can determine safely if the page is beyond EOF. If it is not
4848  * beyond EOF, then the page is guaranteed safe against truncation until we
4849  * unlock the page.
4850  */
4851 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
4852 {
4853         struct page *page = vmf->page;
4854         struct inode *inode = fdentry(vma->vm_file)->d_inode;
4855         struct btrfs_root *root = BTRFS_I(inode)->root;
4856         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4857         struct btrfs_ordered_extent *ordered;
4858         char *kaddr;
4859         unsigned long zero_start;
4860         loff_t size;
4861         int ret;
4862         u64 page_start;
4863         u64 page_end;
4864
4865         ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
4866         if (ret) {
4867                 if (ret == -ENOMEM)
4868                         ret = VM_FAULT_OOM;
4869                 else /* -ENOSPC, -EIO, etc */
4870                         ret = VM_FAULT_SIGBUS;
4871                 goto out;
4872         }
4873
4874         ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
4875         if (ret) {
4876                 btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
4877                 ret = VM_FAULT_SIGBUS;
4878                 goto out;
4879         }
4880
4881         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
4882 again:
4883         lock_page(page);
4884         size = i_size_read(inode);
4885         page_start = page_offset(page);
4886         page_end = page_start + PAGE_CACHE_SIZE - 1;
4887
4888         if ((page->mapping != inode->i_mapping) ||
4889             (page_start >= size)) {
4890                 btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
4891                 /* page got truncated out from underneath us */
4892                 goto out_unlock;
4893         }
4894         wait_on_page_writeback(page);
4895
4896         lock_extent(io_tree, page_start, page_end, GFP_NOFS);
4897         set_page_extent_mapped(page);
4898
4899         /*
4900          * we can't set the delalloc bits if there are pending ordered
4901          * extents.  Drop our locks and wait for them to finish
4902          */
4903         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4904         if (ordered) {
4905                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4906                 unlock_page(page);
4907                 btrfs_start_ordered_extent(inode, ordered, 1);
4908                 btrfs_put_ordered_extent(ordered);
4909                 goto again;
4910         }
4911
4912         /*
4913          * XXX - page_mkwrite gets called every time the page is dirtied, even
4914          * if it was already dirty, so for space accounting reasons we need to
4915          * clear any delalloc bits for the range we are fixing to save.  There
4916          * is probably a better way to do this, but for now keep consistent with
4917          * prepare_pages in the normal write path.
4918          */
4919         clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
4920                           EXTENT_DIRTY | EXTENT_DELALLOC, GFP_NOFS);
4921
4922         ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
4923         if (ret) {
4924                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4925                 ret = VM_FAULT_SIGBUS;
4926                 btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
4927                 goto out_unlock;
4928         }
4929         ret = 0;
4930
4931         /* page is wholly or partially inside EOF */
4932         if (page_start + PAGE_CACHE_SIZE > size)
4933                 zero_start = size & ~PAGE_CACHE_MASK;
4934         else
4935                 zero_start = PAGE_CACHE_SIZE;
4936
4937         if (zero_start != PAGE_CACHE_SIZE) {
4938                 kaddr = kmap(page);
4939                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
4940                 flush_dcache_page(page);
4941                 kunmap(page);
4942         }
4943         ClearPageChecked(page);
4944         set_page_dirty(page);
4945         SetPageUptodate(page);
4946
4947         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
4948         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4949
4950 out_unlock:
4951         btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
4952         if (!ret)
4953                 return VM_FAULT_LOCKED;
4954         unlock_page(page);
4955 out:
4956         return ret;
4957 }
4958
4959 static void btrfs_truncate(struct inode *inode)
4960 {
4961         struct btrfs_root *root = BTRFS_I(inode)->root;
4962         int ret;
4963         struct btrfs_trans_handle *trans;
4964         unsigned long nr;
4965         u64 mask = root->sectorsize - 1;
4966
4967         if (!S_ISREG(inode->i_mode))
4968                 return;
4969         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
4970                 return;
4971
4972         btrfs_truncate_page(inode->i_mapping, inode->i_size);
4973         btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
4974
4975         trans = btrfs_start_transaction(root, 1);
4976
4977         /*
4978          * setattr is responsible for setting the ordered_data_close flag,
4979          * but that is only tested during the last file release.  That
4980          * could happen well after the next commit, leaving a great big
4981          * window where new writes may get lost if someone chooses to write
4982          * to this file after truncating to zero
4983          *
4984          * The inode doesn't have any dirty data here, and so if we commit
4985          * this is a noop.  If someone immediately starts writing to the inode
4986          * it is very likely we'll catch some of their writes in this
4987          * transaction, and the commit will find this file on the ordered
4988          * data list with good things to send down.
4989          *
4990          * This is a best effort solution, there is still a window where
4991          * using truncate to replace the contents of the file will
4992          * end up with a zero length file after a crash.
4993          */
4994         if (inode->i_size == 0 && BTRFS_I(inode)->ordered_data_close)
4995                 btrfs_add_ordered_operation(trans, root, inode);
4996
4997         btrfs_set_trans_block_group(trans, inode);
4998         btrfs_i_size_write(inode, inode->i_size);
4999
5000         ret = btrfs_orphan_add(trans, inode);
5001         if (ret)
5002                 goto out;
5003         /* FIXME, add redo link to tree so we don't leak on crash */
5004         ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size,
5005                                       BTRFS_EXTENT_DATA_KEY);
5006         btrfs_update_inode(trans, root, inode);
5007
5008         ret = btrfs_orphan_del(trans, inode);
5009         BUG_ON(ret);
5010
5011 out:
5012         nr = trans->blocks_used;
5013         ret = btrfs_end_transaction_throttle(trans, root);
5014         BUG_ON(ret);
5015         btrfs_btree_balance_dirty(root, nr);
5016 }
5017
5018 /*
5019  * create a new subvolume directory/inode (helper for the ioctl).
5020  */
5021 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
5022                              struct btrfs_root *new_root,
5023                              u64 new_dirid, u64 alloc_hint)
5024 {
5025         struct inode *inode;
5026         int err;
5027         u64 index = 0;
5028
5029         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
5030                                 new_dirid, alloc_hint, S_IFDIR | 0700, &index);
5031         if (IS_ERR(inode))
5032                 return PTR_ERR(inode);
5033         inode->i_op = &btrfs_dir_inode_operations;
5034         inode->i_fop = &btrfs_dir_file_operations;
5035
5036         inode->i_nlink = 1;
5037         btrfs_i_size_write(inode, 0);
5038
5039         err = btrfs_update_inode(trans, new_root, inode);
5040         BUG_ON(err);
5041
5042         iput(inode);
5043         return 0;
5044 }
5045
5046 /* helper function for file defrag and space balancing.  This
5047  * forces readahead on a given range of bytes in an inode
5048  */
5049 unsigned long btrfs_force_ra(struct address_space *mapping,
5050                               struct file_ra_state *ra, struct file *file,
5051                               pgoff_t offset, pgoff_t last_index)
5052 {
5053         pgoff_t req_size = last_index - offset + 1;
5054
5055         page_cache_sync_readahead(mapping, ra, file, offset, req_size);
5056         return offset + req_size;
5057 }
5058
5059 struct inode *btrfs_alloc_inode(struct super_block *sb)
5060 {
5061         struct btrfs_inode *ei;
5062
5063         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
5064         if (!ei)
5065                 return NULL;
5066         ei->last_trans = 0;
5067         ei->logged_trans = 0;
5068         ei->delalloc_extents = 0;
5069         ei->delalloc_reserved_extents = 0;
5070         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
5071         INIT_LIST_HEAD(&ei->i_orphan);
5072         INIT_LIST_HEAD(&ei->ordered_operations);
5073         return &ei->vfs_inode;
5074 }
5075
5076 void btrfs_destroy_inode(struct inode *inode)
5077 {
5078         struct btrfs_ordered_extent *ordered;
5079         struct btrfs_root *root = BTRFS_I(inode)->root;
5080
5081         WARN_ON(!list_empty(&inode->i_dentry));
5082         WARN_ON(inode->i_data.nrpages);
5083
5084         /*
5085          * Make sure we're properly removed from the ordered operation
5086          * lists.
5087          */
5088         smp_mb();
5089         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
5090                 spin_lock(&root->fs_info->ordered_extent_lock);
5091                 list_del_init(&BTRFS_I(inode)->ordered_operations);
5092                 spin_unlock(&root->fs_info->ordered_extent_lock);
5093         }
5094
5095         spin_lock(&root->list_lock);
5096         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
5097                 printk(KERN_ERR "BTRFS: inode %lu: inode still on the orphan"
5098                        " list\n", inode->i_ino);
5099                 dump_stack();
5100         }
5101         spin_unlock(&root->list_lock);
5102
5103         while (1) {
5104                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
5105                 if (!ordered)
5106                         break;
5107                 else {
5108                         printk(KERN_ERR "btrfs found ordered "
5109                                "extent %llu %llu on inode cleanup\n",
5110                                (unsigned long long)ordered->file_offset,
5111                                (unsigned long long)ordered->len);
5112                         btrfs_remove_ordered_extent(inode, ordered);
5113                         btrfs_put_ordered_extent(ordered);
5114                         btrfs_put_ordered_extent(ordered);
5115                 }
5116         }
5117         inode_tree_del(inode);
5118         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
5119         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
5120 }
5121
5122 void btrfs_drop_inode(struct inode *inode)
5123 {
5124         struct btrfs_root *root = BTRFS_I(inode)->root;
5125
5126         if (inode->i_nlink > 0 && btrfs_root_refs(&root->root_item) == 0)
5127                 generic_delete_inode(inode);
5128         else
5129                 generic_drop_inode(inode);
5130 }
5131
5132 static void init_once(void *foo)
5133 {
5134         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
5135
5136         inode_init_once(&ei->vfs_inode);
5137 }
5138
5139 void btrfs_destroy_cachep(void)
5140 {
5141         if (btrfs_inode_cachep)
5142                 kmem_cache_destroy(btrfs_inode_cachep);
5143         if (btrfs_trans_handle_cachep)
5144                 kmem_cache_destroy(btrfs_trans_handle_cachep);
5145         if (btrfs_transaction_cachep)
5146                 kmem_cache_destroy(btrfs_transaction_cachep);
5147         if (btrfs_path_cachep)
5148                 kmem_cache_destroy(btrfs_path_cachep);
5149 }
5150
5151 int btrfs_init_cachep(void)
5152 {
5153         btrfs_inode_cachep = kmem_cache_create("btrfs_inode_cache",
5154                         sizeof(struct btrfs_inode), 0,
5155                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
5156         if (!btrfs_inode_cachep)
5157                 goto fail;
5158
5159         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle_cache",
5160                         sizeof(struct btrfs_trans_handle), 0,
5161                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
5162         if (!btrfs_trans_handle_cachep)
5163                 goto fail;
5164
5165         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction_cache",
5166                         sizeof(struct btrfs_transaction), 0,
5167                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
5168         if (!btrfs_transaction_cachep)
5169                 goto fail;
5170
5171         btrfs_path_cachep = kmem_cache_create("btrfs_path_cache",
5172                         sizeof(struct btrfs_path), 0,
5173                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
5174         if (!btrfs_path_cachep)
5175                 goto fail;
5176
5177         return 0;
5178 fail:
5179         btrfs_destroy_cachep();
5180         return -ENOMEM;
5181 }
5182
5183 static int btrfs_getattr(struct vfsmount *mnt,
5184                          struct dentry *dentry, struct kstat *stat)
5185 {
5186         struct inode *inode = dentry->d_inode;
5187         generic_fillattr(inode, stat);
5188         stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
5189         stat->blksize = PAGE_CACHE_SIZE;
5190         stat->blocks = (inode_get_bytes(inode) +
5191                         BTRFS_I(inode)->delalloc_bytes) >> 9;
5192         return 0;
5193 }
5194
5195 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
5196                            struct inode *new_dir, struct dentry *new_dentry)
5197 {
5198         struct btrfs_trans_handle *trans;
5199         struct btrfs_root *root = BTRFS_I(old_dir)->root;
5200         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
5201         struct inode *new_inode = new_dentry->d_inode;
5202         struct inode *old_inode = old_dentry->d_inode;
5203         struct timespec ctime = CURRENT_TIME;
5204         u64 index = 0;
5205         u64 root_objectid;
5206         int ret;
5207
5208         if (new_dir->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5209                 return -EPERM;
5210
5211         /* we only allow rename subvolume link between subvolumes */
5212         if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
5213                 return -EXDEV;
5214
5215         if (old_inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
5216             (new_inode && new_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID))
5217                 return -ENOTEMPTY;
5218
5219         if (S_ISDIR(old_inode->i_mode) && new_inode &&
5220             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
5221                 return -ENOTEMPTY;
5222
5223         /*
5224          * 2 items for dir items
5225          * 1 item for orphan entry
5226          * 1 item for ref
5227          */
5228         ret = btrfs_reserve_metadata_space(root, 4);
5229         if (ret)
5230                 return ret;
5231
5232         /*
5233          * we're using rename to replace one file with another.
5234          * and the replacement file is large.  Start IO on it now so
5235          * we don't add too much work to the end of the transaction
5236          */
5237         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
5238             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
5239                 filemap_flush(old_inode->i_mapping);
5240
5241         /* close the racy window with snapshot create/destroy ioctl */
5242         if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
5243                 down_read(&root->fs_info->subvol_sem);
5244
5245         trans = btrfs_start_transaction(root, 1);
5246         btrfs_set_trans_block_group(trans, new_dir);
5247
5248         if (dest != root)
5249                 btrfs_record_root_in_trans(trans, dest);
5250
5251         ret = btrfs_set_inode_index(new_dir, &index);
5252         if (ret)
5253                 goto out_fail;
5254
5255         if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
5256                 /* force full log commit if subvolume involved. */
5257                 root->fs_info->last_trans_log_full_commit = trans->transid;
5258         } else {
5259                 ret = btrfs_insert_inode_ref(trans, dest,
5260                                              new_dentry->d_name.name,
5261                                              new_dentry->d_name.len,
5262                                              old_inode->i_ino,
5263                                              new_dir->i_ino, index);
5264                 if (ret)
5265                         goto out_fail;
5266                 /*
5267                  * this is an ugly little race, but the rename is required
5268                  * to make sure that if we crash, the inode is either at the
5269                  * old name or the new one.  pinning the log transaction lets
5270                  * us make sure we don't allow a log commit to come in after
5271                  * we unlink the name but before we add the new name back in.
5272                  */
5273                 btrfs_pin_log_trans(root);
5274         }
5275         /*
5276          * make sure the inode gets flushed if it is replacing
5277          * something.
5278          */
5279         if (new_inode && new_inode->i_size &&
5280             old_inode && S_ISREG(old_inode->i_mode)) {
5281                 btrfs_add_ordered_operation(trans, root, old_inode);
5282         }
5283
5284         old_dir->i_ctime = old_dir->i_mtime = ctime;
5285         new_dir->i_ctime = new_dir->i_mtime = ctime;
5286         old_inode->i_ctime = ctime;
5287
5288         if (old_dentry->d_parent != new_dentry->d_parent)
5289                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
5290
5291         if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
5292                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
5293                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
5294                                         old_dentry->d_name.name,
5295                                         old_dentry->d_name.len);
5296         } else {
5297                 btrfs_inc_nlink(old_dentry->d_inode);
5298                 ret = btrfs_unlink_inode(trans, root, old_dir,
5299                                          old_dentry->d_inode,
5300                                          old_dentry->d_name.name,
5301                                          old_dentry->d_name.len);
5302         }
5303         BUG_ON(ret);
5304
5305         if (new_inode) {
5306                 new_inode->i_ctime = CURRENT_TIME;
5307                 if (unlikely(new_inode->i_ino ==
5308                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
5309                         root_objectid = BTRFS_I(new_inode)->location.objectid;
5310                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
5311                                                 root_objectid,
5312                                                 new_dentry->d_name.name,
5313                                                 new_dentry->d_name.len);
5314                         BUG_ON(new_inode->i_nlink == 0);
5315                 } else {
5316                         ret = btrfs_unlink_inode(trans, dest, new_dir,
5317                                                  new_dentry->d_inode,
5318                                                  new_dentry->d_name.name,
5319                                                  new_dentry->d_name.len);
5320                 }
5321                 BUG_ON(ret);
5322                 if (new_inode->i_nlink == 0) {
5323                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
5324                         BUG_ON(ret);
5325                 }
5326         }
5327
5328         ret = btrfs_add_link(trans, new_dir, old_inode,
5329                              new_dentry->d_name.name,
5330                              new_dentry->d_name.len, 0, index);
5331         BUG_ON(ret);
5332
5333         if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
5334                 btrfs_log_new_name(trans, old_inode, old_dir,
5335                                    new_dentry->d_parent);
5336                 btrfs_end_log_trans(root);
5337         }
5338 out_fail:
5339         btrfs_end_transaction_throttle(trans, root);
5340
5341         if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
5342                 up_read(&root->fs_info->subvol_sem);
5343
5344         btrfs_unreserve_metadata_space(root, 4);
5345         return ret;
5346 }
5347
5348 /*
5349  * some fairly slow code that needs optimization. This walks the list
5350  * of all the inodes with pending delalloc and forces them to disk.
5351  */
5352 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
5353 {
5354         struct list_head *head = &root->fs_info->delalloc_inodes;
5355         struct btrfs_inode *binode;
5356         struct inode *inode;
5357
5358         if (root->fs_info->sb->s_flags & MS_RDONLY)
5359                 return -EROFS;
5360
5361         spin_lock(&root->fs_info->delalloc_lock);
5362         while (!list_empty(head)) {
5363                 binode = list_entry(head->next, struct btrfs_inode,
5364                                     delalloc_inodes);
5365                 inode = igrab(&binode->vfs_inode);
5366                 if (!inode)
5367                         list_del_init(&binode->delalloc_inodes);
5368                 spin_unlock(&root->fs_info->delalloc_lock);
5369                 if (inode) {
5370                         filemap_flush(inode->i_mapping);
5371                         iput(inode);
5372                 }
5373                 cond_resched();
5374                 spin_lock(&root->fs_info->delalloc_lock);
5375         }
5376         spin_unlock(&root->fs_info->delalloc_lock);
5377
5378         /* the filemap_flush will queue IO into the worker threads, but
5379          * we have to make sure the IO is actually started and that
5380          * ordered extents get created before we return
5381          */
5382         atomic_inc(&root->fs_info->async_submit_draining);
5383         while (atomic_read(&root->fs_info->nr_async_submits) ||
5384               atomic_read(&root->fs_info->async_delalloc_pages)) {
5385                 wait_event(root->fs_info->async_submit_wait,
5386                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
5387                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
5388         }
5389         atomic_dec(&root->fs_info->async_submit_draining);
5390         return 0;
5391 }
5392
5393 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
5394                          const char *symname)
5395 {
5396         struct btrfs_trans_handle *trans;
5397         struct btrfs_root *root = BTRFS_I(dir)->root;
5398         struct btrfs_path *path;
5399         struct btrfs_key key;
5400         struct inode *inode = NULL;
5401         int err;
5402         int drop_inode = 0;
5403         u64 objectid;
5404         u64 index = 0 ;
5405         int name_len;
5406         int datasize;
5407         unsigned long ptr;
5408         struct btrfs_file_extent_item *ei;
5409         struct extent_buffer *leaf;
5410         unsigned long nr = 0;
5411
5412         name_len = strlen(symname) + 1;
5413         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
5414                 return -ENAMETOOLONG;
5415
5416         /*
5417          * 2 items for inode item and ref
5418          * 2 items for dir items
5419          * 1 item for xattr if selinux is on
5420          */
5421         err = btrfs_reserve_metadata_space(root, 5);
5422         if (err)
5423                 return err;
5424
5425         trans = btrfs_start_transaction(root, 1);
5426         if (!trans)
5427                 goto out_fail;
5428         btrfs_set_trans_block_group(trans, dir);
5429
5430         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
5431         if (err) {
5432                 err = -ENOSPC;
5433                 goto out_unlock;
5434         }
5435
5436         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5437                                 dentry->d_name.len,
5438                                 dentry->d_parent->d_inode->i_ino, objectid,
5439                                 BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
5440                                 &index);
5441         err = PTR_ERR(inode);
5442         if (IS_ERR(inode))
5443                 goto out_unlock;
5444
5445         err = btrfs_init_inode_security(inode, dir);
5446         if (err) {
5447                 drop_inode = 1;
5448                 goto out_unlock;
5449         }
5450
5451         btrfs_set_trans_block_group(trans, inode);
5452         err = btrfs_add_nondir(trans, dentry, inode, 0, index);
5453         if (err)
5454                 drop_inode = 1;
5455         else {
5456                 inode->i_mapping->a_ops = &btrfs_aops;
5457                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5458                 inode->i_fop = &btrfs_file_operations;
5459                 inode->i_op = &btrfs_file_inode_operations;
5460                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5461         }
5462         btrfs_update_inode_block_group(trans, inode);
5463         btrfs_update_inode_block_group(trans, dir);
5464         if (drop_inode)
5465                 goto out_unlock;
5466
5467         path = btrfs_alloc_path();
5468         BUG_ON(!path);
5469         key.objectid = inode->i_ino;
5470         key.offset = 0;
5471         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
5472         datasize = btrfs_file_extent_calc_inline_size(name_len);
5473         err = btrfs_insert_empty_item(trans, root, path, &key,
5474                                       datasize);
5475         if (err) {
5476                 drop_inode = 1;
5477                 goto out_unlock;
5478         }
5479         leaf = path->nodes[0];
5480         ei = btrfs_item_ptr(leaf, path->slots[0],
5481                             struct btrfs_file_extent_item);
5482         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
5483         btrfs_set_file_extent_type(leaf, ei,
5484                                    BTRFS_FILE_EXTENT_INLINE);
5485         btrfs_set_file_extent_encryption(leaf, ei, 0);
5486         btrfs_set_file_extent_compression(leaf, ei, 0);
5487         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
5488         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
5489
5490         ptr = btrfs_file_extent_inline_start(ei);
5491         write_extent_buffer(leaf, symname, ptr, name_len);
5492         btrfs_mark_buffer_dirty(leaf);
5493         btrfs_free_path(path);
5494
5495         inode->i_op = &btrfs_symlink_inode_operations;
5496         inode->i_mapping->a_ops = &btrfs_symlink_aops;
5497         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5498         inode_set_bytes(inode, name_len);
5499         btrfs_i_size_write(inode, name_len - 1);
5500         err = btrfs_update_inode(trans, root, inode);
5501         if (err)
5502                 drop_inode = 1;
5503
5504 out_unlock:
5505         nr = trans->blocks_used;
5506         btrfs_end_transaction_throttle(trans, root);
5507 out_fail:
5508         btrfs_unreserve_metadata_space(root, 5);
5509         if (drop_inode) {
5510                 inode_dec_link_count(inode);
5511                 iput(inode);
5512         }
5513         btrfs_btree_balance_dirty(root, nr);
5514         return err;
5515 }
5516
5517 static int prealloc_file_range(struct btrfs_trans_handle *trans,
5518                                struct inode *inode, u64 start, u64 end,
5519                                u64 locked_end, u64 alloc_hint, int mode)
5520 {
5521         struct btrfs_root *root = BTRFS_I(inode)->root;
5522         struct btrfs_key ins;
5523         u64 alloc_size;
5524         u64 cur_offset = start;
5525         u64 num_bytes = end - start;
5526         int ret = 0;
5527
5528         while (num_bytes > 0) {
5529                 alloc_size = min(num_bytes, root->fs_info->max_extent);
5530
5531                 ret = btrfs_reserve_metadata_space(root, 1);
5532                 if (ret)
5533                         goto out;
5534
5535                 ret = btrfs_reserve_extent(trans, root, alloc_size,
5536                                            root->sectorsize, 0, alloc_hint,
5537                                            (u64)-1, &ins, 1);
5538                 if (ret) {
5539                         WARN_ON(1);
5540                         goto out;
5541                 }
5542                 ret = insert_reserved_file_extent(trans, inode,
5543                                                   cur_offset, ins.objectid,
5544                                                   ins.offset, ins.offset,
5545                                                   ins.offset, locked_end,
5546                                                   0, 0, 0,
5547                                                   BTRFS_FILE_EXTENT_PREALLOC);
5548                 BUG_ON(ret);
5549                 btrfs_drop_extent_cache(inode, cur_offset,
5550                                         cur_offset + ins.offset -1, 0);
5551                 num_bytes -= ins.offset;
5552                 cur_offset += ins.offset;
5553                 alloc_hint = ins.objectid + ins.offset;
5554                 btrfs_unreserve_metadata_space(root, 1);
5555         }
5556 out:
5557         if (cur_offset > start) {
5558                 inode->i_ctime = CURRENT_TIME;
5559                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
5560                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
5561                     cur_offset > i_size_read(inode))
5562                         btrfs_i_size_write(inode, cur_offset);
5563                 ret = btrfs_update_inode(trans, root, inode);
5564                 BUG_ON(ret);
5565         }
5566
5567         return ret;
5568 }
5569
5570 static long btrfs_fallocate(struct inode *inode, int mode,
5571                             loff_t offset, loff_t len)
5572 {
5573         u64 cur_offset;
5574         u64 last_byte;
5575         u64 alloc_start;
5576         u64 alloc_end;
5577         u64 alloc_hint = 0;
5578         u64 locked_end;
5579         u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
5580         struct extent_map *em;
5581         struct btrfs_trans_handle *trans;
5582         struct btrfs_root *root;
5583         int ret;
5584
5585         alloc_start = offset & ~mask;
5586         alloc_end =  (offset + len + mask) & ~mask;
5587
5588         /*
5589          * wait for ordered IO before we have any locks.  We'll loop again
5590          * below with the locks held.
5591          */
5592         btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
5593
5594         mutex_lock(&inode->i_mutex);
5595         if (alloc_start > inode->i_size) {
5596                 ret = btrfs_cont_expand(inode, alloc_start);
5597                 if (ret)
5598                         goto out;
5599         }
5600
5601         root = BTRFS_I(inode)->root;
5602
5603         ret = btrfs_check_data_free_space(root, inode,
5604                                           alloc_end - alloc_start);
5605         if (ret)
5606                 goto out;
5607
5608         locked_end = alloc_end - 1;
5609         while (1) {
5610                 struct btrfs_ordered_extent *ordered;
5611
5612                 trans = btrfs_start_transaction(BTRFS_I(inode)->root, 1);
5613                 if (!trans) {
5614                         ret = -EIO;
5615                         goto out_free;
5616                 }
5617
5618                 /* the extent lock is ordered inside the running
5619                  * transaction
5620                  */
5621                 lock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
5622                             GFP_NOFS);
5623                 ordered = btrfs_lookup_first_ordered_extent(inode,
5624                                                             alloc_end - 1);
5625                 if (ordered &&
5626                     ordered->file_offset + ordered->len > alloc_start &&
5627                     ordered->file_offset < alloc_end) {
5628                         btrfs_put_ordered_extent(ordered);
5629                         unlock_extent(&BTRFS_I(inode)->io_tree,
5630                                       alloc_start, locked_end, GFP_NOFS);
5631                         btrfs_end_transaction(trans, BTRFS_I(inode)->root);
5632
5633                         /*
5634                          * we can't wait on the range with the transaction
5635                          * running or with the extent lock held
5636                          */
5637                         btrfs_wait_ordered_range(inode, alloc_start,
5638                                                  alloc_end - alloc_start);
5639                 } else {
5640                         if (ordered)
5641                                 btrfs_put_ordered_extent(ordered);
5642                         break;
5643                 }
5644         }
5645
5646         cur_offset = alloc_start;
5647         while (1) {
5648                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
5649                                       alloc_end - cur_offset, 0);
5650                 BUG_ON(IS_ERR(em) || !em);
5651                 last_byte = min(extent_map_end(em), alloc_end);
5652                 last_byte = (last_byte + mask) & ~mask;
5653                 if (em->block_start == EXTENT_MAP_HOLE) {
5654                         ret = prealloc_file_range(trans, inode, cur_offset,
5655                                         last_byte, locked_end + 1,
5656                                         alloc_hint, mode);
5657                         if (ret < 0) {
5658                                 free_extent_map(em);
5659                                 break;
5660                         }
5661                 }
5662                 if (em->block_start <= EXTENT_MAP_LAST_BYTE)
5663                         alloc_hint = em->block_start;
5664                 free_extent_map(em);
5665
5666                 cur_offset = last_byte;
5667                 if (cur_offset >= alloc_end) {
5668                         ret = 0;
5669                         break;
5670                 }
5671         }
5672         unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
5673                       GFP_NOFS);
5674
5675         btrfs_end_transaction(trans, BTRFS_I(inode)->root);
5676 out_free:
5677         btrfs_free_reserved_data_space(root, inode, alloc_end - alloc_start);
5678 out:
5679         mutex_unlock(&inode->i_mutex);
5680         return ret;
5681 }
5682
5683 static int btrfs_set_page_dirty(struct page *page)
5684 {
5685         return __set_page_dirty_nobuffers(page);
5686 }
5687
5688 static int btrfs_permission(struct inode *inode, int mask)
5689 {
5690         if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE))
5691                 return -EACCES;
5692         return generic_permission(inode, mask, btrfs_check_acl);
5693 }
5694
5695 static const struct inode_operations btrfs_dir_inode_operations = {
5696         .getattr        = btrfs_getattr,
5697         .lookup         = btrfs_lookup,
5698         .create         = btrfs_create,
5699         .unlink         = btrfs_unlink,
5700         .link           = btrfs_link,
5701         .mkdir          = btrfs_mkdir,
5702         .rmdir          = btrfs_rmdir,
5703         .rename         = btrfs_rename,
5704         .symlink        = btrfs_symlink,
5705         .setattr        = btrfs_setattr,
5706         .mknod          = btrfs_mknod,
5707         .setxattr       = btrfs_setxattr,
5708         .getxattr       = btrfs_getxattr,
5709         .listxattr      = btrfs_listxattr,
5710         .removexattr    = btrfs_removexattr,
5711         .permission     = btrfs_permission,
5712 };
5713 static const struct inode_operations btrfs_dir_ro_inode_operations = {
5714         .lookup         = btrfs_lookup,
5715         .permission     = btrfs_permission,
5716 };
5717
5718 static struct file_operations btrfs_dir_file_operations = {
5719         .llseek         = generic_file_llseek,
5720         .read           = generic_read_dir,
5721         .readdir        = btrfs_real_readdir,
5722         .unlocked_ioctl = btrfs_ioctl,
5723 #ifdef CONFIG_COMPAT
5724         .compat_ioctl   = btrfs_ioctl,
5725 #endif
5726         .release        = btrfs_release_file,
5727         .fsync          = btrfs_sync_file,
5728 };
5729
5730 static struct extent_io_ops btrfs_extent_io_ops = {
5731         .fill_delalloc = run_delalloc_range,
5732         .submit_bio_hook = btrfs_submit_bio_hook,
5733         .merge_bio_hook = btrfs_merge_bio_hook,
5734         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
5735         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
5736         .writepage_start_hook = btrfs_writepage_start_hook,
5737         .readpage_io_failed_hook = btrfs_io_failed_hook,
5738         .set_bit_hook = btrfs_set_bit_hook,
5739         .clear_bit_hook = btrfs_clear_bit_hook,
5740         .merge_extent_hook = btrfs_merge_extent_hook,
5741         .split_extent_hook = btrfs_split_extent_hook,
5742 };
5743
5744 /*
5745  * btrfs doesn't support the bmap operation because swapfiles
5746  * use bmap to make a mapping of extents in the file.  They assume
5747  * these extents won't change over the life of the file and they
5748  * use the bmap result to do IO directly to the drive.
5749  *
5750  * the btrfs bmap call would return logical addresses that aren't
5751  * suitable for IO and they also will change frequently as COW
5752  * operations happen.  So, swapfile + btrfs == corruption.
5753  *
5754  * For now we're avoiding this by dropping bmap.
5755  */
5756 static const struct address_space_operations btrfs_aops = {
5757         .readpage       = btrfs_readpage,
5758         .writepage      = btrfs_writepage,
5759         .writepages     = btrfs_writepages,
5760         .readpages      = btrfs_readpages,
5761         .sync_page      = block_sync_page,
5762         .direct_IO      = btrfs_direct_IO,
5763         .invalidatepage = btrfs_invalidatepage,
5764         .releasepage    = btrfs_releasepage,
5765         .set_page_dirty = btrfs_set_page_dirty,
5766         .error_remove_page = generic_error_remove_page,
5767 };
5768
5769 static const struct address_space_operations btrfs_symlink_aops = {
5770         .readpage       = btrfs_readpage,
5771         .writepage      = btrfs_writepage,
5772         .invalidatepage = btrfs_invalidatepage,
5773         .releasepage    = btrfs_releasepage,
5774 };
5775
5776 static const struct inode_operations btrfs_file_inode_operations = {
5777         .truncate       = btrfs_truncate,
5778         .getattr        = btrfs_getattr,
5779         .setattr        = btrfs_setattr,
5780         .setxattr       = btrfs_setxattr,
5781         .getxattr       = btrfs_getxattr,
5782         .listxattr      = btrfs_listxattr,
5783         .removexattr    = btrfs_removexattr,
5784         .permission     = btrfs_permission,
5785         .fallocate      = btrfs_fallocate,
5786         .fiemap         = btrfs_fiemap,
5787 };
5788 static const struct inode_operations btrfs_special_inode_operations = {
5789         .getattr        = btrfs_getattr,
5790         .setattr        = btrfs_setattr,
5791         .permission     = btrfs_permission,
5792         .setxattr       = btrfs_setxattr,
5793         .getxattr       = btrfs_getxattr,
5794         .listxattr      = btrfs_listxattr,
5795         .removexattr    = btrfs_removexattr,
5796 };
5797 static const struct inode_operations btrfs_symlink_inode_operations = {
5798         .readlink       = generic_readlink,
5799         .follow_link    = page_follow_link_light,
5800         .put_link       = page_put_link,
5801         .permission     = btrfs_permission,
5802         .setxattr       = btrfs_setxattr,
5803         .getxattr       = btrfs_getxattr,
5804         .listxattr      = btrfs_listxattr,
5805         .removexattr    = btrfs_removexattr,
5806 };
5807
5808 struct dentry_operations btrfs_dentry_operations = {
5809         .d_delete       = btrfs_dentry_delete,
5810 };