fs/ceph/addr.c

   1 #include <linux/ceph/ceph_debug.h>
   2
   3 #include <linux/backing-dev.h>
   4 #include <linux/fs.h>
   5 #include <linux/mm.h>
   6 #include <linux/pagemap.h>
   7 #include <linux/writeback.h>    /* generic_writepages */
   8 #include <linux/slab.h>
   9 #include <linux/pagevec.h>
  10 #include <linux/task_io_accounting_ops.h>
  11
  12 #include "super.h"
  13 #include "mds_client.h"
  14 #include "cache.h"
  15 #include <linux/ceph/osd_client.h>
  16
  17 /*
  18  * Ceph address space ops.
  19  *
  20  * There are a few funny things going on here.
  21  *
  22  * The page->private field is used to reference a struct
  23  * ceph_snap_context for _every_ dirty page.  This indicates which
  24  * snapshot the page was logically dirtied in, and thus which snap
  25  * context needs to be associated with the osd write during writeback.
  26  *
  27  * Similarly, struct ceph_inode_info maintains a set of counters to
  28  * count dirty pages on the inode.  In the absence of snapshots,
  29  * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
  30  *
  31  * When a snapshot is taken (that is, when the client receives
  32  * notification that a snapshot was taken), each inode with caps and
  33  * with dirty pages (dirty pages implies there is a cap) gets a new
  34  * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
  35  * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
  36  * moved to capsnap->dirty. (Unless a sync write is currently in
  37  * progress.  In that case, the capsnap is said to be "pending", new
  38  * writes cannot start, and the capsnap isn't "finalized" until the
  39  * write completes (or fails) and a final size/mtime for the inode for
  40  * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
  41  *
  42  * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
  43  * we look for the first capsnap in i_cap_snaps and write out pages in
  44  * that snap context _only_.  Then we move on to the next capsnap,
  45  * eventually reaching the "live" or "head" context (i.e., pages that
  46  * are not yet snapped) and are writing the most recently dirtied
  47  * pages.
  48  *
  49  * Invalidate and so forth must take care to ensure the dirty page
  50  * accounting is preserved.
  51  */
  52
  53 #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
  54 #define CONGESTION_OFF_THRESH(congestion_kb)                            \
  55         (CONGESTION_ON_THRESH(congestion_kb) -                          \
  56          (CONGESTION_ON_THRESH(congestion_kb) >> 2))
  57
  58 static inline struct ceph_snap_context *page_snap_context(struct page *page)
  59 {
  60         if (PagePrivate(page))
  61                 return (void *)page->private;
  62         return NULL;
  63 }
  64
  65 /*
  66  * Dirty a page.  Optimistically adjust accounting, on the assumption
  67  * that we won't race with invalidate.  If we do, readjust.
  68  */
  69 static int ceph_set_page_dirty(struct page *page)
  70 {
  71         struct address_space *mapping = page->mapping;
  72         struct inode *inode;
  73         struct ceph_inode_info *ci;
  74         struct ceph_snap_context *snapc;
  75         int ret;
  76
  77         if (unlikely(!mapping))
  78                 return !TestSetPageDirty(page);
  79
  80         if (PageDirty(page)) {
  81                 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
  82                      mapping->host, page, page->index);
  83                 BUG_ON(!PagePrivate(page));
  84                 return 0;
  85         }
  86
  87         inode = mapping->host;
  88         ci = ceph_inode(inode);
  89
  90         /*
  91          * Note that we're grabbing a snapc ref here without holding
  92          * any locks!
  93          */
  94         snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
  95
  96         /* dirty the head */
  97         spin_lock(&ci->i_ceph_lock);
  98         if (ci->i_head_snapc == NULL)
  99                 ci->i_head_snapc = ceph_get_snap_context(snapc);
 100         ++ci->i_wrbuffer_ref_head;
 101         if (ci->i_wrbuffer_ref == 0)
 102                 ihold(inode);
 103         ++ci->i_wrbuffer_ref;
 104         dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
 105              "snapc %p seq %lld (%d snaps)\n",
 106              mapping->host, page, page->index,
 107              ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
 108              ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
 109              snapc, snapc->seq, snapc->num_snaps);
 110         spin_unlock(&ci->i_ceph_lock);
 111
 112         /*
 113          * Reference snap context in page->private.  Also set
 114          * PagePrivate so that we get invalidatepage callback.
 115          */
 116         BUG_ON(PagePrivate(page));
 117         page->private = (unsigned long)snapc;
 118         SetPagePrivate(page);
 119
 120         ret = __set_page_dirty_nobuffers(page);
 121         WARN_ON(!PageLocked(page));
 122         WARN_ON(!page->mapping);
 123
 124         return ret;
 125 }
 126
 127 /*
 128  * If we are truncating the full page (i.e. offset == 0), adjust the
 129  * dirty page counters appropriately.  Only called if there is private
 130  * data on the page.
 131  */
 132 static void ceph_invalidatepage(struct page *page, unsigned int offset,
 133                                 unsigned int length)
 134 {
 135         struct inode *inode;
 136         struct ceph_inode_info *ci;
 137         struct ceph_snap_context *snapc = page_snap_context(page);
 138
 139         inode = page->mapping->host;
 140         ci = ceph_inode(inode);
 141
 142         if (offset != 0 || length != PAGE_CACHE_SIZE) {
 143                 dout("%p invalidatepage %p idx %lu partial dirty page %u~%u\n",
 144                      inode, page, page->index, offset, length);
 145                 return;
 146         }
 147
 148         ceph_invalidate_fscache_page(inode, page);
 149
 150         if (!PagePrivate(page))
 151                 return;
 152
 153         /*
 154          * We can get non-dirty pages here due to races between
 155          * set_page_dirty and truncate_complete_page; just spit out a
 156          * warning, in case we end up with accounting problems later.
 157          */
 158         if (!PageDirty(page))
 159                 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
 160
 161         ClearPageChecked(page);
 162
 163         dout("%p invalidatepage %p idx %lu full dirty page\n",
 164              inode, page, page->index);
 165
 166         ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 167         ceph_put_snap_context(snapc);
 168         page->private = 0;
 169         ClearPagePrivate(page);
 170 }
 171
 172 static int ceph_releasepage(struct page *page, gfp_t g)
 173 {
 174         struct inode *inode = page->mapping ? page->mapping->host : NULL;
 175         dout("%p releasepage %p idx %lu\n", inode, page, page->index);
 176         WARN_ON(PageDirty(page));
 177
 178         /* Can we release the page from the cache? */
 179         if (!ceph_release_fscache_page(page, g))
 180                 return 0;
 181
 182         return !PagePrivate(page);
 183 }
 184
 185 /*
 186  * read a single page, without unlocking it.
 187  */
 188 static int readpage_nounlock(struct file *filp, struct page *page)
 189 {
 190         struct inode *inode = file_inode(filp);
 191         struct ceph_inode_info *ci = ceph_inode(inode);
 192         struct ceph_osd_client *osdc =
 193                 &ceph_inode_to_client(inode)->client->osdc;
 194         int err = 0;
 195         u64 off = page_offset(page);
 196         u64 len = PAGE_CACHE_SIZE;
 197
 198         if (off >= i_size_read(inode)) {
 199                 zero_user_segment(page, err, PAGE_CACHE_SIZE);
 200                 SetPageUptodate(page);
 201                 return 0;
 202         }
 203
 204         /*
 205          * Uptodate inline data should have been added into page cache
 206          * while getting Fcr caps.
 207          */
 208         if (ci->i_inline_version != CEPH_INLINE_NONE)
 209                 return -EINVAL;
 210
 211         err = ceph_readpage_from_fscache(inode, page);
 212         if (err == 0)
 213                 goto out;
 214
 215         dout("readpage inode %p file %p page %p index %lu\n",
 216              inode, filp, page, page->index);
 217         err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
 218                                   off, &len,
 219                                   ci->i_truncate_seq, ci->i_truncate_size,
 220                                   &page, 1, 0);
 221         if (err == -ENOENT)
 222                 err = 0;
 223         if (err < 0) {
 224                 SetPageError(page);
 225                 ceph_fscache_readpage_cancel(inode, page);
 226                 goto out;
 227         }
 228         if (err < PAGE_CACHE_SIZE)
 229                 /* zero fill remainder of page */
 230                 zero_user_segment(page, err, PAGE_CACHE_SIZE);
 231         else
 232                 flush_dcache_page(page);
 233
 234         SetPageUptodate(page);
 235         ceph_readpage_to_fscache(inode, page);
 236
 237 out:
 238         return err < 0 ? err : 0;
 239 }
 240
 241 static int ceph_readpage(struct file *filp, struct page *page)
 242 {
 243         int r = readpage_nounlock(filp, page);
 244         unlock_page(page);
 245         return r;
 246 }
 247
 248 /*
 249  * Finish an async read(ahead) op.
 250  */
 251 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
 252 {
 253         struct inode *inode = req->r_inode;
 254         struct ceph_osd_data *osd_data;
 255         int rc = req->r_result;
 256         int bytes = le32_to_cpu(msg->hdr.data_len);
 257         int num_pages;
 258         int i;
 259
 260         dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
 261
 262         /* unlock all pages, zeroing any data we didn't read */
 263         osd_data = osd_req_op_extent_osd_data(req, 0);
 264         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
 265         num_pages = calc_pages_for((u64)osd_data->alignment,
 266                                         (u64)osd_data->length);
 267         for (i = 0; i < num_pages; i++) {
 268                 struct page *page = osd_data->pages[i];
 269
 270                 if (rc < 0)
 271                         goto unlock;
 272                 if (bytes < (int)PAGE_CACHE_SIZE) {
 273                         /* zero (remainder of) page */
 274                         int s = bytes < 0 ? 0 : bytes;
 275                         zero_user_segment(page, s, PAGE_CACHE_SIZE);
 276                 }
 277                 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
 278                      page->index);
 279                 flush_dcache_page(page);
 280                 SetPageUptodate(page);
 281                 ceph_readpage_to_fscache(inode, page);
 282 unlock:
 283                 unlock_page(page);
 284                 page_cache_release(page);
 285                 bytes -= PAGE_CACHE_SIZE;
 286         }
 287         kfree(osd_data->pages);
 288 }
 289
 290 static void ceph_unlock_page_vector(struct page **pages, int num_pages)
 291 {
 292         int i;
 293
 294         for (i = 0; i < num_pages; i++)
 295                 unlock_page(pages[i]);
 296 }
 297
 298 /*
 299  * start an async read(ahead) operation.  return nr_pages we submitted
 300  * a read for on success, or negative error code.
 301  */
 302 static int start_read(struct inode *inode, struct list_head *page_list, int max)
 303 {
 304         struct ceph_osd_client *osdc =
 305                 &ceph_inode_to_client(inode)->client->osdc;
 306         struct ceph_inode_info *ci = ceph_inode(inode);
 307         struct page *page = list_entry(page_list->prev, struct page, lru);
 308         struct ceph_vino vino;
 309         struct ceph_osd_request *req;
 310         u64 off;
 311         u64 len;
 312         int i;
 313         struct page **pages;
 314         pgoff_t next_index;
 315         int nr_pages = 0;
 316         int ret;
 317
 318         off = (u64) page_offset(page);
 319
 320         /* count pages */
 321         next_index = page->index;
 322         list_for_each_entry_reverse(page, page_list, lru) {
 323                 if (page->index != next_index)
 324                         break;
 325                 nr_pages++;
 326                 next_index++;
 327                 if (max && nr_pages == max)
 328                         break;
 329         }
 330         len = nr_pages << PAGE_CACHE_SHIFT;
 331         dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
 332              off, len);
 333         vino = ceph_vino(inode);
 334         req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
 335                                     0, 1, CEPH_OSD_OP_READ,
 336                                     CEPH_OSD_FLAG_READ, NULL,
 337                                     ci->i_truncate_seq, ci->i_truncate_size,
 338                                     false);
 339         if (IS_ERR(req))
 340                 return PTR_ERR(req);
 341
 342         /* build page vector */
 343         nr_pages = calc_pages_for(0, len);
 344         pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
 345         ret = -ENOMEM;
 346         if (!pages)
 347                 goto out;
 348         for (i = 0; i < nr_pages; ++i) {
 349                 page = list_entry(page_list->prev, struct page, lru);
 350                 BUG_ON(PageLocked(page));
 351                 list_del(&page->lru);
 352
 353                 dout("start_read %p adding %p idx %lu\n", inode, page,
 354                      page->index);
 355                 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
 356                                           GFP_NOFS)) {
 357                         ceph_fscache_uncache_page(inode, page);
 358                         page_cache_release(page);
 359                         dout("start_read %p add_to_page_cache failed %p\n",
 360                              inode, page);
 361                         nr_pages = i;
 362                         goto out_pages;
 363                 }
 364                 pages[i] = page;
 365         }
 366         osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
 367         req->r_callback = finish_read;
 368         req->r_inode = inode;
 369
 370         ceph_osdc_build_request(req, off, NULL, vino.snap, NULL);
 371
 372         dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
 373         ret = ceph_osdc_start_request(osdc, req, false);
 374         if (ret < 0)
 375                 goto out_pages;
 376         ceph_osdc_put_request(req);
 377         return nr_pages;
 378
 379 out_pages:
 380         ceph_unlock_page_vector(pages, nr_pages);
 381         ceph_release_page_vector(pages, nr_pages);
 382 out:
 383         ceph_osdc_put_request(req);
 384         return ret;
 385 }
 386
 387
 388 /*
 389  * Read multiple pages.  Leave pages we don't read + unlock in page_list;
 390  * the caller (VM) cleans them up.
 391  */
 392 static int ceph_readpages(struct file *file, struct address_space *mapping,
 393                           struct list_head *page_list, unsigned nr_pages)
 394 {
 395         struct inode *inode = file_inode(file);
 396         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 397         int rc = 0;
 398         int max = 0;
 399
 400         if (ceph_inode(inode)->i_inline_version != CEPH_INLINE_NONE)
 401                 return -EINVAL;
 402
 403         rc = ceph_readpages_from_fscache(mapping->host, mapping, page_list,
 404                                          &nr_pages);
 405
 406         if (rc == 0)
 407                 goto out;
 408
 409         if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
 410                 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
 411                         >> PAGE_SHIFT;
 412
 413         dout("readpages %p file %p nr_pages %d max %d\n", inode,
 414                 file, nr_pages,
 415              max);
 416         while (!list_empty(page_list)) {
 417                 rc = start_read(inode, page_list, max);
 418                 if (rc < 0)
 419                         goto out;
 420                 BUG_ON(rc == 0);
 421         }
 422 out:
 423         ceph_fscache_readpages_cancel(inode, page_list);
 424
 425         dout("readpages %p file %p ret %d\n", inode, file, rc);
 426         return rc;
 427 }
 428
 429 /*
 430  * Get ref for the oldest snapc for an inode with dirty data... that is, the
 431  * only snap context we are allowed to write back.
 432  */
 433 static struct ceph_snap_context *get_oldest_context(struct inode *inode,
 434                                                     u64 *snap_size)
 435 {
 436         struct ceph_inode_info *ci = ceph_inode(inode);
 437         struct ceph_snap_context *snapc = NULL;
 438         struct ceph_cap_snap *capsnap = NULL;
 439
 440         spin_lock(&ci->i_ceph_lock);
 441         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
 442                 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
 443                      capsnap->context, capsnap->dirty_pages);
 444                 if (capsnap->dirty_pages) {
 445                         snapc = ceph_get_snap_context(capsnap->context);
 446                         if (snap_size)
 447                                 *snap_size = capsnap->size;
 448                         break;
 449                 }
 450         }
 451         if (!snapc && ci->i_wrbuffer_ref_head) {
 452                 snapc = ceph_get_snap_context(ci->i_head_snapc);
 453                 dout(" head snapc %p has %d dirty pages\n",
 454                      snapc, ci->i_wrbuffer_ref_head);
 455         }
 456         spin_unlock(&ci->i_ceph_lock);
 457         return snapc;
 458 }
 459
 460 /*
 461  * Write a single page, but leave the page locked.
 462  *
 463  * If we get a write error, set the page error bit, but still adjust the
 464  * dirty page accounting (i.e., page is no longer dirty).
 465  */
 466 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 467 {
 468         struct inode *inode;
 469         struct ceph_inode_info *ci;
 470         struct ceph_fs_client *fsc;
 471         struct ceph_osd_client *osdc;
 472         struct ceph_snap_context *snapc, *oldest;
 473         loff_t page_off = page_offset(page);
 474         long writeback_stat;
 475         u64 truncate_size, snap_size = 0;
 476         u32 truncate_seq;
 477         int err = 0, len = PAGE_CACHE_SIZE;
 478
 479         dout("writepage %p idx %lu\n", page, page->index);
 480
 481         if (!page->mapping || !page->mapping->host) {
 482                 dout("writepage %p - no mapping\n", page);
 483                 return -EFAULT;
 484         }
 485         inode = page->mapping->host;
 486         ci = ceph_inode(inode);
 487         fsc = ceph_inode_to_client(inode);
 488         osdc = &fsc->client->osdc;
 489
 490         /* verify this is a writeable snap context */
 491         snapc = page_snap_context(page);
 492         if (snapc == NULL) {
 493                 dout("writepage %p page %p not dirty?\n", inode, page);
 494                 goto out;
 495         }
 496         oldest = get_oldest_context(inode, &snap_size);
 497         if (snapc->seq > oldest->seq) {
 498                 dout("writepage %p page %p snapc %p not writeable - noop\n",
 499                      inode, page, snapc);
 500                 /* we should only noop if called by kswapd */
 501                 WARN_ON((current->flags & PF_MEMALLOC) == 0);
 502                 ceph_put_snap_context(oldest);
 503                 goto out;
 504         }
 505         ceph_put_snap_context(oldest);
 506
 507         spin_lock(&ci->i_ceph_lock);
 508         truncate_seq = ci->i_truncate_seq;
 509         truncate_size = ci->i_truncate_size;
 510         if (!snap_size)
 511                 snap_size = i_size_read(inode);
 512         spin_unlock(&ci->i_ceph_lock);
 513
 514         /* is this a partial page at end of file? */
 515         if (page_off >= snap_size) {
 516                 dout("%p page eof %llu\n", page, snap_size);
 517                 goto out;
 518         }
 519         if (snap_size < page_off + len)
 520                 len = snap_size - page_off;
 521
 522         dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
 523              inode, page, page->index, page_off, len, snapc);
 524
 525         writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
 526         if (writeback_stat >
 527             CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
 528                 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
 529
 530         ceph_readpage_to_fscache(inode, page);
 531
 532         set_page_writeback(page);
 533         err = ceph_osdc_writepages(osdc, ceph_vino(inode),
 534                                    &ci->i_layout, snapc,
 535                                    page_off, len,
 536                                    truncate_seq, truncate_size,
 537                                    &inode->i_mtime, &page, 1);
 538         if (err < 0) {
 539                 dout("writepage setting page/mapping error %d %p\n", err, page);
 540                 SetPageError(page);
 541                 mapping_set_error(&inode->i_data, err);
 542                 if (wbc)
 543                         wbc->pages_skipped++;
 544         } else {
 545                 dout("writepage cleaned page %p\n", page);
 546                 err = 0;  /* vfs expects us to return 0 */
 547         }
 548         page->private = 0;
 549         ClearPagePrivate(page);
 550         end_page_writeback(page);
 551         ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 552         ceph_put_snap_context(snapc);  /* page's reference */
 553 out:
 554         return err;
 555 }
 556
 557 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 558 {
 559         int err;
 560         struct inode *inode = page->mapping->host;
 561         BUG_ON(!inode);
 562         ihold(inode);
 563         err = writepage_nounlock(page, wbc);
 564         unlock_page(page);
 565         iput(inode);
 566         return err;
 567 }
 568
 569
 570 /*
 571  * lame release_pages helper.  release_pages() isn't exported to
 572  * modules.
 573  */
 574 static void ceph_release_pages(struct page **pages, int num)
 575 {
 576         struct pagevec pvec;
 577         int i;
 578
 579         pagevec_init(&pvec, 0);
 580         for (i = 0; i < num; i++) {
 581                 if (pagevec_add(&pvec, pages[i]) == 0)
 582                         pagevec_release(&pvec);
 583         }
 584         pagevec_release(&pvec);
 585 }
 586
 587 /*
 588  * async writeback completion handler.
 589  *
 590  * If we get an error, set the mapping error bit, but not the individual
 591  * page error bits.
 592  */
 593 static void writepages_finish(struct ceph_osd_request *req,
 594                               struct ceph_msg *msg)
 595 {
 596         struct inode *inode = req->r_inode;
 597         struct ceph_inode_info *ci = ceph_inode(inode);
 598         struct ceph_osd_data *osd_data;
 599         unsigned wrote;
 600         struct page *page;
 601         int num_pages;
 602         int i;
 603         struct ceph_snap_context *snapc = req->r_snapc;
 604         struct address_space *mapping = inode->i_mapping;
 605         int rc = req->r_result;
 606         u64 bytes = req->r_ops[0].extent.length;
 607         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 608         long writeback_stat;
 609         unsigned issued = ceph_caps_issued(ci);
 610
 611         osd_data = osd_req_op_extent_osd_data(req, 0);
 612         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
 613         num_pages = calc_pages_for((u64)osd_data->alignment,
 614                                         (u64)osd_data->length);
 615         if (rc >= 0) {
 616                 /*
 617                  * Assume we wrote the pages we originally sent.  The
 618                  * osd might reply with fewer pages if our writeback
 619                  * raced with a truncation and was adjusted at the osd,
 620                  * so don't believe the reply.
 621                  */
 622                 wrote = num_pages;
 623         } else {
 624                 wrote = 0;
 625                 mapping_set_error(mapping, rc);
 626         }
 627         dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
 628              inode, rc, bytes, wrote);
 629
 630         /* clean all pages */
 631         for (i = 0; i < num_pages; i++) {
 632                 page = osd_data->pages[i];
 633                 BUG_ON(!page);
 634                 WARN_ON(!PageUptodate(page));
 635
 636                 writeback_stat =
 637                         atomic_long_dec_return(&fsc->writeback_count);
 638                 if (writeback_stat <
 639                     CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
 640                         clear_bdi_congested(&fsc->backing_dev_info,
 641                                             BLK_RW_ASYNC);
 642
 643                 ceph_put_snap_context(page_snap_context(page));
 644                 page->private = 0;
 645                 ClearPagePrivate(page);
 646                 dout("unlocking %d %p\n", i, page);
 647                 end_page_writeback(page);
 648
 649                 /*
 650                  * We lost the cache cap, need to truncate the page before
 651                  * it is unlocked, otherwise we'd truncate it later in the
 652                  * page truncation thread, possibly losing some data that
 653                  * raced its way in
 654                  */
 655                 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
 656                         generic_error_remove_page(inode->i_mapping, page);
 657
 658                 unlock_page(page);
 659         }
 660         dout("%p wrote+cleaned %d pages\n", inode, wrote);
 661         ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc);
 662
 663         ceph_release_pages(osd_data->pages, num_pages);
 664         if (osd_data->pages_from_pool)
 665                 mempool_free(osd_data->pages,
 666                              ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
 667         else
 668                 kfree(osd_data->pages);
 669         ceph_osdc_put_request(req);
 670 }
 671
 672 /*
 673  * initiate async writeback
 674  */
 675 static int ceph_writepages_start(struct address_space *mapping,
 676                                  struct writeback_control *wbc)
 677 {
 678         struct inode *inode = mapping->host;
 679         struct ceph_inode_info *ci = ceph_inode(inode);
 680         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 681         struct ceph_vino vino = ceph_vino(inode);
 682         pgoff_t index, start, end;
 683         int range_whole = 0;
 684         int should_loop = 1;
 685         pgoff_t max_pages = 0, max_pages_ever = 0;
 686         struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
 687         struct pagevec pvec;
 688         int done = 0;
 689         int rc = 0;
 690         unsigned wsize = 1 << inode->i_blkbits;
 691         struct ceph_osd_request *req = NULL;
 692         int do_sync = 0;
 693         u64 truncate_size, snap_size;
 694         u32 truncate_seq;
 695
 696         /*
 697          * Include a 'sync' in the OSD request if this is a data
 698          * integrity write (e.g., O_SYNC write or fsync()), or if our
 699          * cap is being revoked.
 700          */
 701         if ((wbc->sync_mode == WB_SYNC_ALL) ||
 702                 ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
 703                 do_sync = 1;
 704         dout("writepages_start %p dosync=%d (mode=%s)\n",
 705              inode, do_sync,
 706              wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
 707              (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
 708
 709         if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
 710                 pr_warn("writepage_start %p on forced umount\n", inode);
 711                 return -EIO; /* we're in a forced umount, don't write! */
 712         }
 713         if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
 714                 wsize = fsc->mount_options->wsize;
 715         if (wsize < PAGE_CACHE_SIZE)
 716                 wsize = PAGE_CACHE_SIZE;
 717         max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
 718
 719         pagevec_init(&pvec, 0);
 720
 721         /* where to start/end? */
 722         if (wbc->range_cyclic) {
 723                 start = mapping->writeback_index; /* Start from prev offset */
 724                 end = -1;
 725                 dout(" cyclic, start at %lu\n", start);
 726         } else {
 727                 start = wbc->range_start >> PAGE_CACHE_SHIFT;
 728                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
 729                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 730                         range_whole = 1;
 731                 should_loop = 0;
 732                 dout(" not cyclic, %lu to %lu\n", start, end);
 733         }
 734         index = start;
 735
 736 retry:
 737         /* find oldest snap context with dirty data */
 738         ceph_put_snap_context(snapc);
 739         snap_size = 0;
 740         snapc = get_oldest_context(inode, &snap_size);
 741         if (!snapc) {
 742                 /* hmm, why does writepages get called when there
 743                    is no dirty data? */
 744                 dout(" no snap context with dirty data?\n");
 745                 goto out;
 746         }
 747         if (snap_size == 0)
 748                 snap_size = i_size_read(inode);
 749         dout(" oldest snapc is %p seq %lld (%d snaps)\n",
 750              snapc, snapc->seq, snapc->num_snaps);
 751
 752         spin_lock(&ci->i_ceph_lock);
 753         truncate_seq = ci->i_truncate_seq;
 754         truncate_size = ci->i_truncate_size;
 755         if (!snap_size)
 756                 snap_size = i_size_read(inode);
 757         spin_unlock(&ci->i_ceph_lock);
 758
 759         if (last_snapc && snapc != last_snapc) {
 760                 /* if we switched to a newer snapc, restart our scan at the
 761                  * start of the original file range. */
 762                 dout("  snapc differs from last pass, restarting at %lu\n",
 763                      index);
 764                 index = start;
 765         }
 766         last_snapc = snapc;
 767
 768         while (!done && index <= end) {
 769                 unsigned i;
 770                 int first;
 771                 pgoff_t next;
 772                 int pvec_pages, locked_pages;
 773                 struct page **pages = NULL;
 774                 mempool_t *pool = NULL; /* Becomes non-null if mempool used */
 775                 struct page *page;
 776                 int want;
 777                 u64 offset, len;
 778                 long writeback_stat;
 779
 780                 next = 0;
 781                 locked_pages = 0;
 782                 max_pages = max_pages_ever;
 783
 784 get_more_pages:
 785                 first = -1;
 786                 want = min(end - index,
 787                            min((pgoff_t)PAGEVEC_SIZE,
 788                                max_pages - (pgoff_t)locked_pages) - 1)
 789                         + 1;
 790                 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 791                                                 PAGECACHE_TAG_DIRTY,
 792                                                 want);
 793                 dout("pagevec_lookup_tag got %d\n", pvec_pages);
 794                 if (!pvec_pages && !locked_pages)
 795                         break;
 796                 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
 797                         page = pvec.pages[i];
 798                         dout("? %p idx %lu\n", page, page->index);
 799                         if (locked_pages == 0)
 800                                 lock_page(page);  /* first page */
 801                         else if (!trylock_page(page))
 802                                 break;
 803
 804                         /* only dirty pages, or our accounting breaks */
 805                         if (unlikely(!PageDirty(page)) ||
 806                             unlikely(page->mapping != mapping)) {
 807                                 dout("!dirty or !mapping %p\n", page);
 808                                 unlock_page(page);
 809                                 break;
 810                         }
 811                         if (!wbc->range_cyclic && page->index > end) {
 812                                 dout("end of range %p\n", page);
 813                                 done = 1;
 814                                 unlock_page(page);
 815                                 break;
 816                         }
 817                         if (next && (page->index != next)) {
 818                                 dout("not consecutive %p\n", page);
 819                                 unlock_page(page);
 820                                 break;
 821                         }
 822                         if (wbc->sync_mode != WB_SYNC_NONE) {
 823                                 dout("waiting on writeback %p\n", page);
 824                                 wait_on_page_writeback(page);
 825                         }
 826                         if (page_offset(page) >= snap_size) {
 827                                 dout("%p page eof %llu\n", page, snap_size);
 828                                 done = 1;
 829                                 unlock_page(page);
 830                                 break;
 831                         }
 832                         if (PageWriteback(page)) {
 833                                 dout("%p under writeback\n", page);
 834                                 unlock_page(page);
 835                                 break;
 836                         }
 837
 838                         /* only if matching snap context */
 839                         pgsnapc = page_snap_context(page);
 840                         if (pgsnapc->seq > snapc->seq) {
 841                                 dout("page snapc %p %lld > oldest %p %lld\n",
 842                                      pgsnapc, pgsnapc->seq, snapc, snapc->seq);
 843                                 unlock_page(page);
 844                                 if (!locked_pages)
 845                                         continue; /* keep looking for snap */
 846                                 break;
 847                         }
 848
 849                         if (!clear_page_dirty_for_io(page)) {
 850                                 dout("%p !clear_page_dirty_for_io\n", page);
 851                                 unlock_page(page);
 852                                 break;
 853                         }
 854
 855                         /*
 856                          * We have something to write.  If this is
 857                          * the first locked page this time through,
 858                          * allocate an osd request and a page array
 859                          * that it will use.
 860                          */
 861                         if (locked_pages == 0) {
 862                                 BUG_ON(pages);
 863                                 /* prepare async write request */
 864                                 offset = (u64)page_offset(page);
 865                                 len = wsize;
 866                                 req = ceph_osdc_new_request(&fsc->client->osdc,
 867                                                         &ci->i_layout, vino,
 868                                                         offset, &len, 0,
 869                                                         do_sync ? 2 : 1,
 870                                                         CEPH_OSD_OP_WRITE,
 871                                                         CEPH_OSD_FLAG_WRITE |
 872                                                         CEPH_OSD_FLAG_ONDISK,
 873                                                         snapc, truncate_seq,
 874                                                         truncate_size, true);
 875                                 if (IS_ERR(req)) {
 876                                         rc = PTR_ERR(req);
 877                                         unlock_page(page);
 878                                         break;
 879                                 }
 880
 881                                 if (do_sync)
 882                                         osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC);
 883
 884                                 req->r_callback = writepages_finish;
 885                                 req->r_inode = inode;
 886
 887                                 max_pages = calc_pages_for(0, (u64)len);
 888                                 pages = kmalloc(max_pages * sizeof (*pages),
 889                                                 GFP_NOFS);
 890                                 if (!pages) {
 891                                         pool = fsc->wb_pagevec_pool;
 892                                         pages = mempool_alloc(pool, GFP_NOFS);
 893                                         BUG_ON(!pages);
 894                                 }
 895                         }
 896
 897                         /* note position of first page in pvec */
 898                         if (first < 0)
 899                                 first = i;
 900                         dout("%p will write page %p idx %lu\n",
 901                              inode, page, page->index);
 902
 903                         writeback_stat =
 904                                atomic_long_inc_return(&fsc->writeback_count);
 905                         if (writeback_stat > CONGESTION_ON_THRESH(
 906                                     fsc->mount_options->congestion_kb)) {
 907                                 set_bdi_congested(&fsc->backing_dev_info,
 908                                                   BLK_RW_ASYNC);
 909                         }
 910
 911                         set_page_writeback(page);
 912                         pages[locked_pages] = page;
 913                         locked_pages++;
 914                         next = page->index + 1;
 915                 }
 916
 917                 /* did we get anything? */
 918                 if (!locked_pages)
 919                         goto release_pvec_pages;
 920                 if (i) {
 921                         int j;
 922                         BUG_ON(!locked_pages || first < 0);
 923
 924                         if (pvec_pages && i == pvec_pages &&
 925                             locked_pages < max_pages) {
 926                                 dout("reached end pvec, trying for more\n");
 927                                 pagevec_reinit(&pvec);
 928                                 goto get_more_pages;
 929                         }
 930
 931                         /* shift unused pages over in the pvec...  we
 932                          * will need to release them below. */
 933                         for (j = i; j < pvec_pages; j++) {
 934                                 dout(" pvec leftover page %p\n",
 935                                      pvec.pages[j]);
 936                                 pvec.pages[j-i+first] = pvec.pages[j];
 937                         }
 938                         pvec.nr -= i-first;
 939                 }
 940
 941                 /* Format the osd request message and submit the write */
 942
 943                 offset = page_offset(pages[0]);
 944                 len = min(snap_size - offset,
 945                           (u64)locked_pages << PAGE_CACHE_SHIFT);
 946                 dout("writepages got %d pages at %llu~%llu\n",
 947                      locked_pages, offset, len);
 948
 949                 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
 950                                                         !!pool, false);
 951
 952                 pages = NULL;   /* request message now owns the pages array */
 953                 pool = NULL;
 954
 955                 /* Update the write op length in case we changed it */
 956
 957                 osd_req_op_extent_update(req, 0, len);
 958
 959                 vino = ceph_vino(inode);
 960                 ceph_osdc_build_request(req, offset, snapc, vino.snap,
 961                                         &inode->i_mtime);
 962
 963                 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
 964                 BUG_ON(rc);
 965                 req = NULL;
 966
 967                 /* continue? */
 968                 index = next;
 969                 wbc->nr_to_write -= locked_pages;
 970                 if (wbc->nr_to_write <= 0)
 971                         done = 1;
 972
 973 release_pvec_pages:
 974                 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
 975                      pvec.nr ? pvec.pages[0] : NULL);
 976                 pagevec_release(&pvec);
 977
 978                 if (locked_pages && !done)
 979                         goto retry;
 980         }
 981
 982         if (should_loop && !done) {
 983                 /* more to do; loop back to beginning of file */
 984                 dout("writepages looping back to beginning of file\n");
 985                 should_loop = 0;
 986                 index = 0;
 987                 goto retry;
 988         }
 989
 990         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 991                 mapping->writeback_index = index;
 992
 993 out:
 994         if (req)
 995                 ceph_osdc_put_request(req);
 996         ceph_put_snap_context(snapc);
 997         dout("writepages done, rc = %d\n", rc);
 998         return rc;
 999 }
1000
1001
1002
1003 /*
1004  * See if a given @snapc is either writeable, or already written.
1005  */
1006 static int context_is_writeable_or_written(struct inode *inode,
1007                                            struct ceph_snap_context *snapc)
1008 {
1009         struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
1010         int ret = !oldest || snapc->seq <= oldest->seq;
1011
1012         ceph_put_snap_context(oldest);
1013         return ret;
1014 }
1015
1016 /*
1017  * We are only allowed to write into/dirty the page if the page is
1018  * clean, or already dirty within the same snap context.
1019  *
1020  * called with page locked.
1021  * return success with page locked,
1022  * or any failure (incl -EAGAIN) with page unlocked.
1023  */
1024 static int ceph_update_writeable_page(struct file *file,
1025                             loff_t pos, unsigned len,
1026                             struct page *page)
1027 {
1028         struct inode *inode = file_inode(file);
1029         struct ceph_inode_info *ci = ceph_inode(inode);
1030         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1031         loff_t page_off = pos & PAGE_CACHE_MASK;
1032         int pos_in_page = pos & ~PAGE_CACHE_MASK;
1033         int end_in_page = pos_in_page + len;
1034         loff_t i_size;
1035         int r;
1036         struct ceph_snap_context *snapc, *oldest;
1037
1038 retry_locked:
1039         /* writepages currently holds page lock, but if we change that later, */
1040         wait_on_page_writeback(page);
1041
1042         /* check snap context */
1043         BUG_ON(!ci->i_snap_realm);
1044         down_read(&mdsc->snap_rwsem);
1045         BUG_ON(!ci->i_snap_realm->cached_context);
1046         snapc = page_snap_context(page);
1047         if (snapc && snapc != ci->i_head_snapc) {
1048                 /*
1049                  * this page is already dirty in another (older) snap
1050                  * context!  is it writeable now?
1051                  */
1052                 oldest = get_oldest_context(inode, NULL);
1053                 up_read(&mdsc->snap_rwsem);
1054
1055                 if (snapc->seq > oldest->seq) {
1056                         ceph_put_snap_context(oldest);
1057                         dout(" page %p snapc %p not current or oldest\n",
1058                              page, snapc);
1059                         /*
1060                          * queue for writeback, and wait for snapc to
1061                          * be writeable or written
1062                          */
1063                         snapc = ceph_get_snap_context(snapc);
1064                         unlock_page(page);
1065                         ceph_queue_writeback(inode);
1066                         r = wait_event_interruptible(ci->i_cap_wq,
1067                                context_is_writeable_or_written(inode, snapc));
1068                         ceph_put_snap_context(snapc);
1069                         if (r == -ERESTARTSYS)
1070                                 return r;
1071                         return -EAGAIN;
1072                 }
1073                 ceph_put_snap_context(oldest);
1074
1075                 /* yay, writeable, do it now (without dropping page lock) */
1076                 dout(" page %p snapc %p not current, but oldest\n",
1077                      page, snapc);
1078                 if (!clear_page_dirty_for_io(page))
1079                         goto retry_locked;
1080                 r = writepage_nounlock(page, NULL);
1081                 if (r < 0)
1082                         goto fail_nosnap;
1083                 goto retry_locked;
1084         }
1085
1086         if (PageUptodate(page)) {
1087                 dout(" page %p already uptodate\n", page);
1088                 return 0;
1089         }
1090
1091         /* full page? */
1092         if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
1093                 return 0;
1094
1095         /* past end of file? */
1096         i_size = inode->i_size;   /* caller holds i_mutex */
1097
1098         if (page_off >= i_size ||
1099             (pos_in_page == 0 && (pos+len) >= i_size &&
1100              end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1101                 dout(" zeroing %p 0 - %d and %d - %d\n",
1102                      page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1103                 zero_user_segments(page,
1104                                    0, pos_in_page,
1105                                    end_in_page, PAGE_CACHE_SIZE);
1106                 return 0;
1107         }
1108
1109         /* we need to read it. */
1110         up_read(&mdsc->snap_rwsem);
1111         r = readpage_nounlock(file, page);
1112         if (r < 0)
1113                 goto fail_nosnap;
1114         goto retry_locked;
1115 fail_nosnap:
1116         unlock_page(page);
1117         return r;
1118 }
1119
1120 /*
1121  * We are only allowed to write into/dirty the page if the page is
1122  * clean, or already dirty within the same snap context.
1123  */
1124 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1125                             loff_t pos, unsigned len, unsigned flags,
1126                             struct page **pagep, void **fsdata)
1127 {
1128         struct inode *inode = file_inode(file);
1129         struct page *page;
1130         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1131         int r;
1132
1133         do {
1134                 /* get a page */
1135                 page = grab_cache_page_write_begin(mapping, index, 0);
1136                 if (!page)
1137                         return -ENOMEM;
1138                 *pagep = page;
1139
1140                 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1141                      inode, page, (int)pos, (int)len);
1142
1143                 r = ceph_update_writeable_page(file, pos, len, page);
1144         } while (r == -EAGAIN);
1145
1146         return r;
1147 }
1148
1149 /*
1150  * we don't do anything in here that simple_write_end doesn't do
1151  * except adjust dirty page accounting and drop read lock on
1152  * mdsc->snap_rwsem.
1153  */
1154 static int ceph_write_end(struct file *file, struct address_space *mapping,
1155                           loff_t pos, unsigned len, unsigned copied,
1156                           struct page *page, void *fsdata)
1157 {
1158         struct inode *inode = file_inode(file);
1159         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1160         struct ceph_mds_client *mdsc = fsc->mdsc;
1161         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1162         int check_cap = 0;
1163
1164         dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1165              inode, page, (int)pos, (int)copied, (int)len);
1166
1167         /* zero the stale part of the page if we did a short copy */
1168         if (copied < len)
1169                 zero_user_segment(page, from+copied, len);
1170
1171         /* did file size increase? */
1172         /* (no need for i_size_read(); we caller holds i_mutex */
1173         if (pos+copied > inode->i_size)
1174                 check_cap = ceph_inode_set_size(inode, pos+copied);
1175
1176         if (!PageUptodate(page))
1177                 SetPageUptodate(page);
1178
1179         set_page_dirty(page);
1180
1181         unlock_page(page);
1182         up_read(&mdsc->snap_rwsem);
1183         page_cache_release(page);
1184
1185         if (check_cap)
1186                 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1187
1188         return copied;
1189 }
1190
1191 /*
1192  * we set .direct_IO to indicate direct io is supported, but since we
1193  * intercept O_DIRECT reads and writes early, this function should
1194  * never get called.
1195  */
1196 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1197                               struct iov_iter *iter,
1198                               loff_t pos)
1199 {
1200         WARN_ON(1);
1201         return -EINVAL;
1202 }
1203
1204 const struct address_space_operations ceph_aops = {
1205         .readpage = ceph_readpage,
1206         .readpages = ceph_readpages,
1207         .writepage = ceph_writepage,
1208         .writepages = ceph_writepages_start,
1209         .write_begin = ceph_write_begin,
1210         .write_end = ceph_write_end,
1211         .set_page_dirty = ceph_set_page_dirty,
1212         .invalidatepage = ceph_invalidatepage,
1213         .releasepage = ceph_releasepage,
1214         .direct_IO = ceph_direct_io,
1215 };
1216
1217
1218 /*
1219  * vm ops
1220  */
1221 static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1222 {
1223         struct inode *inode = file_inode(vma->vm_file);
1224         struct ceph_inode_info *ci = ceph_inode(inode);
1225         struct ceph_file_info *fi = vma->vm_file->private_data;
1226         struct page *pinned_page = NULL;
1227         loff_t off = vmf->pgoff << PAGE_CACHE_SHIFT;
1228         int want, got, ret;
1229
1230         dout("filemap_fault %p %llx.%llx %llu~%zd trying to get caps\n",
1231              inode, ceph_vinop(inode), off, (size_t)PAGE_CACHE_SIZE);
1232         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1233                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
1234         else
1235                 want = CEPH_CAP_FILE_CACHE;
1236         while (1) {
1237                 got = 0;
1238                 ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want,
1239                                     -1, &got, &pinned_page);
1240                 if (ret == 0)
1241                         break;
1242                 if (ret != -ERESTARTSYS) {
1243                         WARN_ON(1);
1244                         return VM_FAULT_SIGBUS;
1245                 }
1246         }
1247         dout("filemap_fault %p %llu~%zd got cap refs on %s\n",
1248              inode, off, (size_t)PAGE_CACHE_SIZE, ceph_cap_string(got));
1249
1250         if ((got & (CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO)) ||
1251             ci->i_inline_version == CEPH_INLINE_NONE)
1252                 ret = filemap_fault(vma, vmf);
1253         else
1254                 ret = -EAGAIN;
1255
1256         dout("filemap_fault %p %llu~%zd dropping cap refs on %s ret %d\n",
1257              inode, off, (size_t)PAGE_CACHE_SIZE, ceph_cap_string(got), ret);
1258         if (pinned_page)
1259                 page_cache_release(pinned_page);
1260         ceph_put_cap_refs(ci, got);
1261
1262         if (ret != -EAGAIN)
1263                 return ret;
1264
1265         /* read inline data */
1266         if (off >= PAGE_CACHE_SIZE) {
1267                 /* does not support inline data > PAGE_SIZE */
1268                 ret = VM_FAULT_SIGBUS;
1269         } else {
1270                 int ret1;
1271                 struct address_space *mapping = inode->i_mapping;
1272                 struct page *page = find_or_create_page(mapping, 0,
1273                                                 mapping_gfp_mask(mapping) &
1274                                                 ~__GFP_FS);
1275                 if (!page) {
1276                         ret = VM_FAULT_OOM;
1277                         goto out;
1278                 }
1279                 ret1 = __ceph_do_getattr(inode, page,
1280                                          CEPH_STAT_CAP_INLINE_DATA, true);
1281                 if (ret1 < 0 || off >= i_size_read(inode)) {
1282                         unlock_page(page);
1283                         page_cache_release(page);
1284                         ret = VM_FAULT_SIGBUS;
1285                         goto out;
1286                 }
1287                 if (ret1 < PAGE_CACHE_SIZE)
1288                         zero_user_segment(page, ret1, PAGE_CACHE_SIZE);
1289                 else
1290                         flush_dcache_page(page);
1291                 SetPageUptodate(page);
1292                 vmf->page = page;
1293                 ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
1294         }
1295 out:
1296         dout("filemap_fault %p %llu~%zd read inline data ret %d\n",
1297              inode, off, (size_t)PAGE_CACHE_SIZE, ret);
1298         return ret;
1299 }
1300
1301 /*
1302  * Reuse write_begin here for simplicity.
1303  */
1304 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1305 {
1306         struct inode *inode = file_inode(vma->vm_file);
1307         struct ceph_inode_info *ci = ceph_inode(inode);
1308         struct ceph_file_info *fi = vma->vm_file->private_data;
1309         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1310         struct page *page = vmf->page;
1311         loff_t off = page_offset(page);
1312         loff_t size = i_size_read(inode);
1313         size_t len;
1314         int want, got, ret;
1315
1316         if (ci->i_inline_version != CEPH_INLINE_NONE) {
1317                 struct page *locked_page = NULL;
1318                 if (off == 0) {
1319                         lock_page(page);
1320                         locked_page = page;
1321                 }
1322                 ret = ceph_uninline_data(vma->vm_file, locked_page);
1323                 if (locked_page)
1324                         unlock_page(locked_page);
1325                 if (ret < 0)
1326                         return VM_FAULT_SIGBUS;
1327         }
1328
1329         if (off + PAGE_CACHE_SIZE <= size)
1330                 len = PAGE_CACHE_SIZE;
1331         else
1332                 len = size & ~PAGE_CACHE_MASK;
1333
1334         dout("page_mkwrite %p %llx.%llx %llu~%zd getting caps i_size %llu\n",
1335              inode, ceph_vinop(inode), off, len, size);
1336         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1337                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1338         else
1339                 want = CEPH_CAP_FILE_BUFFER;
1340         while (1) {
1341                 got = 0;
1342                 ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
1343                                     &got, NULL);
1344                 if (ret == 0)
1345                         break;
1346                 if (ret != -ERESTARTSYS) {
1347                         WARN_ON(1);
1348                         return VM_FAULT_SIGBUS;
1349                 }
1350         }
1351         dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
1352              inode, off, len, ceph_cap_string(got));
1353
1354         /* Update time before taking page lock */
1355         file_update_time(vma->vm_file);
1356
1357         lock_page(page);
1358
1359         ret = VM_FAULT_NOPAGE;
1360         if ((off > size) ||
1361             (page->mapping != inode->i_mapping))
1362                 goto out;
1363
1364         ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1365         if (ret == 0) {
1366                 /* success.  we'll keep the page locked. */
1367                 set_page_dirty(page);
1368                 up_read(&mdsc->snap_rwsem);
1369                 ret = VM_FAULT_LOCKED;
1370         } else {
1371                 if (ret == -ENOMEM)
1372                         ret = VM_FAULT_OOM;
1373                 else
1374                         ret = VM_FAULT_SIGBUS;
1375         }
1376 out:
1377         if (ret != VM_FAULT_LOCKED)
1378                 unlock_page(page);
1379         if (ret == VM_FAULT_LOCKED ||
1380             ci->i_inline_version != CEPH_INLINE_NONE) {
1381                 int dirty;
1382                 spin_lock(&ci->i_ceph_lock);
1383                 ci->i_inline_version = CEPH_INLINE_NONE;
1384                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
1385                 spin_unlock(&ci->i_ceph_lock);
1386                 if (dirty)
1387                         __mark_inode_dirty(inode, dirty);
1388         }
1389
1390         dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %d\n",
1391              inode, off, len, ceph_cap_string(got), ret);
1392         ceph_put_cap_refs(ci, got);
1393
1394         return ret;
1395 }
1396
1397 void ceph_fill_inline_data(struct inode *inode, struct page *locked_page,
1398                            char *data, size_t len)
1399 {
1400         struct address_space *mapping = inode->i_mapping;
1401         struct page *page;
1402
1403         if (locked_page) {
1404                 page = locked_page;
1405         } else {
1406                 if (i_size_read(inode) == 0)
1407                         return;
1408                 page = find_or_create_page(mapping, 0,
1409                                            mapping_gfp_mask(mapping) & ~__GFP_FS);
1410                 if (!page)
1411                         return;
1412                 if (PageUptodate(page)) {
1413                         unlock_page(page);
1414                         page_cache_release(page);
1415                         return;
1416                 }
1417         }
1418
1419         dout("fill_inline_data %p %llx.%llx len %zu locked_page %p\n",
1420              inode, ceph_vinop(inode), len, locked_page);
1421
1422         if (len > 0) {
1423                 void *kaddr = kmap_atomic(page);
1424                 memcpy(kaddr, data, len);
1425                 kunmap_atomic(kaddr);
1426         }
1427
1428         if (page != locked_page) {
1429                 if (len < PAGE_CACHE_SIZE)
1430                         zero_user_segment(page, len, PAGE_CACHE_SIZE);
1431                 else
1432                         flush_dcache_page(page);
1433
1434                 SetPageUptodate(page);
1435                 unlock_page(page);
1436                 page_cache_release(page);
1437         }
1438 }
1439
1440 int ceph_uninline_data(struct file *filp, struct page *locked_page)
1441 {
1442         struct inode *inode = file_inode(filp);
1443         struct ceph_inode_info *ci = ceph_inode(inode);
1444         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1445         struct ceph_osd_request *req;
1446         struct page *page = NULL;
1447         u64 len, inline_version;
1448         int err = 0;
1449         bool from_pagecache = false;
1450
1451         spin_lock(&ci->i_ceph_lock);
1452         inline_version = ci->i_inline_version;
1453         spin_unlock(&ci->i_ceph_lock);
1454
1455         dout("uninline_data %p %llx.%llx inline_version %llu\n",
1456              inode, ceph_vinop(inode), inline_version);
1457
1458         if (inline_version == 1 || /* initial version, no data */
1459             inline_version == CEPH_INLINE_NONE)
1460                 goto out;
1461
1462         if (locked_page) {
1463                 page = locked_page;
1464                 WARN_ON(!PageUptodate(page));
1465         } else if (ceph_caps_issued(ci) &
1466                    (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) {
1467                 page = find_get_page(inode->i_mapping, 0);
1468                 if (page) {
1469                         if (PageUptodate(page)) {
1470                                 from_pagecache = true;
1471                                 lock_page(page);
1472                         } else {
1473                                 page_cache_release(page);
1474                                 page = NULL;
1475                         }
1476                 }
1477         }
1478
1479         if (page) {
1480                 len = i_size_read(inode);
1481                 if (len > PAGE_CACHE_SIZE)
1482                         len = PAGE_CACHE_SIZE;
1483         } else {
1484                 page = __page_cache_alloc(GFP_NOFS);
1485                 if (!page) {
1486                         err = -ENOMEM;
1487                         goto out;
1488                 }
1489                 err = __ceph_do_getattr(inode, page,
1490                                         CEPH_STAT_CAP_INLINE_DATA, true);
1491                 if (err < 0) {
1492                         /* no inline data */
1493                         if (err == -ENODATA)
1494                                 err = 0;
1495                         goto out;
1496                 }
1497                 len = err;
1498         }
1499
1500         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1501                                     ceph_vino(inode), 0, &len, 0, 1,
1502                                     CEPH_OSD_OP_CREATE,
1503                                     CEPH_OSD_FLAG_ONDISK | CEPH_OSD_FLAG_WRITE,
1504                                     ci->i_snap_realm->cached_context,
1505                                     0, 0, false);
1506         if (IS_ERR(req)) {
1507                 err = PTR_ERR(req);
1508                 goto out;
1509         }
1510
1511         ceph_osdc_build_request(req, 0, NULL, CEPH_NOSNAP, &inode->i_mtime);
1512         err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1513         if (!err)
1514                 err = ceph_osdc_wait_request(&fsc->client->osdc, req);
1515         ceph_osdc_put_request(req);
1516         if (err < 0)
1517                 goto out;
1518
1519         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1520                                     ceph_vino(inode), 0, &len, 1, 3,
1521                                     CEPH_OSD_OP_WRITE,
1522                                     CEPH_OSD_FLAG_ONDISK | CEPH_OSD_FLAG_WRITE,
1523                                     ci->i_snap_realm->cached_context,
1524                                     ci->i_truncate_seq, ci->i_truncate_size,
1525                                     false);
1526         if (IS_ERR(req)) {
1527                 err = PTR_ERR(req);
1528                 goto out;
1529         }
1530
1531         osd_req_op_extent_osd_data_pages(req, 1, &page, len, 0, false, false);
1532
1533         err = osd_req_op_xattr_init(req, 0, CEPH_OSD_OP_CMPXATTR,
1534                                     "inline_version", &inline_version,
1535                                     sizeof(inline_version),
1536                                     CEPH_OSD_CMPXATTR_OP_GT,
1537                                     CEPH_OSD_CMPXATTR_MODE_U64);
1538         if (err)
1539                 goto out_put;
1540
1541         err = osd_req_op_xattr_init(req, 2, CEPH_OSD_OP_SETXATTR,
1542                                     "inline_version", &inline_version,
1543                                     sizeof(inline_version), 0, 0);
1544         if (err)
1545                 goto out_put;
1546
1547         ceph_osdc_build_request(req, 0, NULL, CEPH_NOSNAP, &inode->i_mtime);
1548         err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1549         if (!err)
1550                 err = ceph_osdc_wait_request(&fsc->client->osdc, req);
1551 out_put:
1552         ceph_osdc_put_request(req);
1553         if (err == -ECANCELED)
1554                 err = 0;
1555 out:
1556         if (page && page != locked_page) {
1557                 if (from_pagecache) {
1558                         unlock_page(page);
1559                         page_cache_release(page);
1560                 } else
1561                         __free_pages(page, 0);
1562         }
1563
1564         dout("uninline_data %p %llx.%llx inline_version %llu = %d\n",
1565              inode, ceph_vinop(inode), inline_version, err);
1566         return err;
1567 }
1568
1569 static struct vm_operations_struct ceph_vmops = {
1570         .fault          = ceph_filemap_fault,
1571         .page_mkwrite   = ceph_page_mkwrite,
1572         .remap_pages    = generic_file_remap_pages,
1573 };
1574
1575 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1576 {
1577         struct address_space *mapping = file->f_mapping;
1578
1579         if (!mapping->a_ops->readpage)
1580                 return -ENOEXEC;
1581         file_accessed(file);
1582         vma->vm_ops = &ceph_vmops;
1583         return 0;
1584 }