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 <linux/ceph/osd_client.h>
  15
  16 /*
  17  * Ceph address space ops.
  18  *
  19  * There are a few funny things going on here.
  20  *
  21  * The page->private field is used to reference a struct
  22  * ceph_snap_context for _every_ dirty page.  This indicates which
  23  * snapshot the page was logically dirtied in, and thus which snap
  24  * context needs to be associated with the osd write during writeback.
  25  *
  26  * Similarly, struct ceph_inode_info maintains a set of counters to
  27  * count dirty pages on the inode.  In the absence of snapshots,
  28  * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
  29  *
  30  * When a snapshot is taken (that is, when the client receives
  31  * notification that a snapshot was taken), each inode with caps and
  32  * with dirty pages (dirty pages implies there is a cap) gets a new
  33  * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
  34  * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
  35  * moved to capsnap->dirty. (Unless a sync write is currently in
  36  * progress.  In that case, the capsnap is said to be "pending", new
  37  * writes cannot start, and the capsnap isn't "finalized" until the
  38  * write completes (or fails) and a final size/mtime for the inode for
  39  * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
  40  *
  41  * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
  42  * we look for the first capsnap in i_cap_snaps and write out pages in
  43  * that snap context _only_.  Then we move on to the next capsnap,
  44  * eventually reaching the "live" or "head" context (i.e., pages that
  45  * are not yet snapped) and are writing the most recently dirtied
  46  * pages.
  47  *
  48  * Invalidate and so forth must take care to ensure the dirty page
  49  * accounting is preserved.
  50  */
  51
  52 #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
  53 #define CONGESTION_OFF_THRESH(congestion_kb)                            \
  54         (CONGESTION_ON_THRESH(congestion_kb) -                          \
  55          (CONGESTION_ON_THRESH(congestion_kb) >> 2))
  56
  57 static inline struct ceph_snap_context *page_snap_context(struct page *page)
  58 {
  59         if (PagePrivate(page))
  60                 return (void *)page->private;
  61         return NULL;
  62 }
  63
  64 /*
  65  * Dirty a page.  Optimistically adjust accounting, on the assumption
  66  * that we won't race with invalidate.  If we do, readjust.
  67  */
  68 static int ceph_set_page_dirty(struct page *page)
  69 {
  70         struct address_space *mapping = page->mapping;
  71         struct inode *inode;
  72         struct ceph_inode_info *ci;
  73         int undo = 0;
  74         struct ceph_snap_context *snapc;
  75
  76         if (unlikely(!mapping))
  77                 return !TestSetPageDirty(page);
  78
  79         if (TestSetPageDirty(page)) {
  80                 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
  81                      mapping->host, page, page->index);
  82                 return 0;
  83         }
  84
  85         inode = mapping->host;
  86         ci = ceph_inode(inode);
  87
  88         /*
  89          * Note that we're grabbing a snapc ref here without holding
  90          * any locks!
  91          */
  92         snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
  93
  94         /* dirty the head */
  95         spin_lock(&ci->i_ceph_lock);
  96         if (ci->i_head_snapc == NULL)
  97                 ci->i_head_snapc = ceph_get_snap_context(snapc);
  98         ++ci->i_wrbuffer_ref_head;
  99         if (ci->i_wrbuffer_ref == 0)
 100                 ihold(inode);
 101         ++ci->i_wrbuffer_ref;
 102         dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
 103              "snapc %p seq %lld (%d snaps)\n",
 104              mapping->host, page, page->index,
 105              ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
 106              ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
 107              snapc, snapc->seq, snapc->num_snaps);
 108         spin_unlock(&ci->i_ceph_lock);
 109
 110         /* now adjust page */
 111         spin_lock_irq(&mapping->tree_lock);
 112         if (page->mapping) {    /* Race with truncate? */
 113                 WARN_ON_ONCE(!PageUptodate(page));
 114                 account_page_dirtied(page, page->mapping);
 115                 radix_tree_tag_set(&mapping->page_tree,
 116                                 page_index(page), PAGECACHE_TAG_DIRTY);
 117
 118                 /*
 119                  * Reference snap context in page->private.  Also set
 120                  * PagePrivate so that we get invalidatepage callback.
 121                  */
 122                 page->private = (unsigned long)snapc;
 123                 SetPagePrivate(page);
 124         } else {
 125                 dout("ANON set_page_dirty %p (raced truncate?)\n", page);
 126                 undo = 1;
 127         }
 128
 129         spin_unlock_irq(&mapping->tree_lock);
 130
 131         if (undo)
 132                 /* whoops, we failed to dirty the page */
 133                 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 134
 135         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 136
 137         BUG_ON(!PageDirty(page));
 138         return 1;
 139 }
 140
 141 /*
 142  * If we are truncating the full page (i.e. offset == 0), adjust the
 143  * dirty page counters appropriately.  Only called if there is private
 144  * data on the page.
 145  */
 146 static void ceph_invalidatepage(struct page *page, unsigned long offset)
 147 {
 148         struct inode *inode;
 149         struct ceph_inode_info *ci;
 150         struct ceph_snap_context *snapc = page_snap_context(page);
 151
 152         BUG_ON(!PageLocked(page));
 153         BUG_ON(!PagePrivate(page));
 154         BUG_ON(!page->mapping);
 155
 156         inode = page->mapping->host;
 157
 158         /*
 159          * We can get non-dirty pages here due to races between
 160          * set_page_dirty and truncate_complete_page; just spit out a
 161          * warning, in case we end up with accounting problems later.
 162          */
 163         if (!PageDirty(page))
 164                 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
 165
 166         if (offset == 0)
 167                 ClearPageChecked(page);
 168
 169         ci = ceph_inode(inode);
 170         if (offset == 0) {
 171                 dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
 172                      inode, page, page->index, offset);
 173                 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 174                 ceph_put_snap_context(snapc);
 175                 page->private = 0;
 176                 ClearPagePrivate(page);
 177         } else {
 178                 dout("%p invalidatepage %p idx %lu partial dirty page\n",
 179                      inode, page, page->index);
 180         }
 181 }
 182
 183 /* just a sanity check */
 184 static int ceph_releasepage(struct page *page, gfp_t g)
 185 {
 186         struct inode *inode = page->mapping ? page->mapping->host : NULL;
 187         dout("%p releasepage %p idx %lu\n", inode, page, page->index);
 188         WARN_ON(PageDirty(page));
 189         WARN_ON(PagePrivate(page));
 190         return 0;
 191 }
 192
 193 /*
 194  * read a single page, without unlocking it.
 195  */
 196 static int readpage_nounlock(struct file *filp, struct page *page)
 197 {
 198         struct inode *inode = file_inode(filp);
 199         struct ceph_inode_info *ci = ceph_inode(inode);
 200         struct ceph_osd_client *osdc =
 201                 &ceph_inode_to_client(inode)->client->osdc;
 202         int err = 0;
 203         u64 len = PAGE_CACHE_SIZE;
 204
 205         dout("readpage inode %p file %p page %p index %lu\n",
 206              inode, filp, page, page->index);
 207         err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
 208                                   (u64) page_offset(page), &len,
 209                                   ci->i_truncate_seq, ci->i_truncate_size,
 210                                   &page, 1, 0);
 211         if (err == -ENOENT)
 212                 err = 0;
 213         if (err < 0) {
 214                 SetPageError(page);
 215                 goto out;
 216         } else if (err < PAGE_CACHE_SIZE) {
 217                 /* zero fill remainder of page */
 218                 zero_user_segment(page, err, PAGE_CACHE_SIZE);
 219         }
 220         SetPageUptodate(page);
 221
 222 out:
 223         return err < 0 ? err : 0;
 224 }
 225
 226 static int ceph_readpage(struct file *filp, struct page *page)
 227 {
 228         int r = readpage_nounlock(filp, page);
 229         unlock_page(page);
 230         return r;
 231 }
 232
 233 /*
 234  * Finish an async read(ahead) op.
 235  */
 236 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
 237 {
 238         struct inode *inode = req->r_inode;
 239         int rc = req->r_result;
 240         int bytes = le32_to_cpu(msg->hdr.data_len);
 241         int i;
 242
 243         dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
 244
 245         /* unlock all pages, zeroing any data we didn't read */
 246         for (i = 0; i < req->r_num_pages; i++, bytes -= PAGE_CACHE_SIZE) {
 247                 struct page *page = req->r_pages[i];
 248
 249                 if (bytes < (int)PAGE_CACHE_SIZE) {
 250                         /* zero (remainder of) page */
 251                         int s = bytes < 0 ? 0 : bytes;
 252                         zero_user_segment(page, s, PAGE_CACHE_SIZE);
 253                 }
 254                 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
 255                      page->index);
 256                 flush_dcache_page(page);
 257                 SetPageUptodate(page);
 258                 unlock_page(page);
 259                 page_cache_release(page);
 260         }
 261         kfree(req->r_pages);
 262 }
 263
 264 static void ceph_unlock_page_vector(struct page **pages, int num_pages)
 265 {
 266         int i;
 267
 268         for (i = 0; i < num_pages; i++)
 269                 unlock_page(pages[i]);
 270 }
 271
 272 /*
 273  * start an async read(ahead) operation.  return nr_pages we submitted
 274  * a read for on success, or negative error code.
 275  */
 276 static int start_read(struct inode *inode, struct list_head *page_list, int max)
 277 {
 278         struct ceph_osd_client *osdc =
 279                 &ceph_inode_to_client(inode)->client->osdc;
 280         struct ceph_inode_info *ci = ceph_inode(inode);
 281         struct page *page = list_entry(page_list->prev, struct page, lru);
 282         struct ceph_osd_request *req;
 283         u64 off;
 284         u64 len;
 285         int i;
 286         struct page **pages;
 287         pgoff_t next_index;
 288         int nr_pages = 0;
 289         int ret;
 290
 291         off = (u64) page_offset(page);
 292
 293         /* count pages */
 294         next_index = page->index;
 295         list_for_each_entry_reverse(page, page_list, lru) {
 296                 if (page->index != next_index)
 297                         break;
 298                 nr_pages++;
 299                 next_index++;
 300                 if (max && nr_pages == max)
 301                         break;
 302         }
 303         len = nr_pages << PAGE_CACHE_SHIFT;
 304         dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
 305              off, len);
 306
 307         req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode),
 308                                     off, &len,
 309                                     CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ,
 310                                     NULL, 0,
 311                                     ci->i_truncate_seq, ci->i_truncate_size,
 312                                     NULL, false, 0);
 313         if (IS_ERR(req))
 314                 return PTR_ERR(req);
 315
 316         /* build page vector */
 317         nr_pages = len >> PAGE_CACHE_SHIFT;
 318         pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
 319         ret = -ENOMEM;
 320         if (!pages)
 321                 goto out;
 322         for (i = 0; i < nr_pages; ++i) {
 323                 page = list_entry(page_list->prev, struct page, lru);
 324                 BUG_ON(PageLocked(page));
 325                 list_del(&page->lru);
 326
 327                 dout("start_read %p adding %p idx %lu\n", inode, page,
 328                      page->index);
 329                 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
 330                                           GFP_NOFS)) {
 331                         page_cache_release(page);
 332                         dout("start_read %p add_to_page_cache failed %p\n",
 333                              inode, page);
 334                         nr_pages = i;
 335                         goto out_pages;
 336                 }
 337                 pages[i] = page;
 338         }
 339         req->r_pages = pages;
 340         req->r_num_pages = nr_pages;
 341         req->r_callback = finish_read;
 342         req->r_inode = inode;
 343
 344         dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
 345         ret = ceph_osdc_start_request(osdc, req, false);
 346         if (ret < 0)
 347                 goto out_pages;
 348         ceph_osdc_put_request(req);
 349         return nr_pages;
 350
 351 out_pages:
 352         ceph_unlock_page_vector(pages, nr_pages);
 353         ceph_release_page_vector(pages, nr_pages);
 354 out:
 355         ceph_osdc_put_request(req);
 356         return ret;
 357 }
 358
 359
 360 /*
 361  * Read multiple pages.  Leave pages we don't read + unlock in page_list;
 362  * the caller (VM) cleans them up.
 363  */
 364 static int ceph_readpages(struct file *file, struct address_space *mapping,
 365                           struct list_head *page_list, unsigned nr_pages)
 366 {
 367         struct inode *inode = file_inode(file);
 368         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 369         int rc = 0;
 370         int max = 0;
 371
 372         if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
 373                 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
 374                         >> PAGE_SHIFT;
 375
 376         dout("readpages %p file %p nr_pages %d max %d\n", inode, file, nr_pages,
 377              max);
 378         while (!list_empty(page_list)) {
 379                 rc = start_read(inode, page_list, max);
 380                 if (rc < 0)
 381                         goto out;
 382                 BUG_ON(rc == 0);
 383         }
 384 out:
 385         dout("readpages %p file %p ret %d\n", inode, file, rc);
 386         return rc;
 387 }
 388
 389 /*
 390  * Get ref for the oldest snapc for an inode with dirty data... that is, the
 391  * only snap context we are allowed to write back.
 392  */
 393 static struct ceph_snap_context *get_oldest_context(struct inode *inode,
 394                                                     u64 *snap_size)
 395 {
 396         struct ceph_inode_info *ci = ceph_inode(inode);
 397         struct ceph_snap_context *snapc = NULL;
 398         struct ceph_cap_snap *capsnap = NULL;
 399
 400         spin_lock(&ci->i_ceph_lock);
 401         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
 402                 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
 403                      capsnap->context, capsnap->dirty_pages);
 404                 if (capsnap->dirty_pages) {
 405                         snapc = ceph_get_snap_context(capsnap->context);
 406                         if (snap_size)
 407                                 *snap_size = capsnap->size;
 408                         break;
 409                 }
 410         }
 411         if (!snapc && ci->i_wrbuffer_ref_head) {
 412                 snapc = ceph_get_snap_context(ci->i_head_snapc);
 413                 dout(" head snapc %p has %d dirty pages\n",
 414                      snapc, ci->i_wrbuffer_ref_head);
 415         }
 416         spin_unlock(&ci->i_ceph_lock);
 417         return snapc;
 418 }
 419
 420 /*
 421  * Write a single page, but leave the page locked.
 422  *
 423  * If we get a write error, set the page error bit, but still adjust the
 424  * dirty page accounting (i.e., page is no longer dirty).
 425  */
 426 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 427 {
 428         struct inode *inode;
 429         struct ceph_inode_info *ci;
 430         struct ceph_fs_client *fsc;
 431         struct ceph_osd_client *osdc;
 432         loff_t page_off = page_offset(page);
 433         int len = PAGE_CACHE_SIZE;
 434         loff_t i_size;
 435         int err = 0;
 436         struct ceph_snap_context *snapc, *oldest;
 437         u64 snap_size = 0;
 438         long writeback_stat;
 439
 440         dout("writepage %p idx %lu\n", page, page->index);
 441
 442         if (!page->mapping || !page->mapping->host) {
 443                 dout("writepage %p - no mapping\n", page);
 444                 return -EFAULT;
 445         }
 446         inode = page->mapping->host;
 447         ci = ceph_inode(inode);
 448         fsc = ceph_inode_to_client(inode);
 449         osdc = &fsc->client->osdc;
 450
 451         /* verify this is a writeable snap context */
 452         snapc = page_snap_context(page);
 453         if (snapc == NULL) {
 454                 dout("writepage %p page %p not dirty?\n", inode, page);
 455                 goto out;
 456         }
 457         oldest = get_oldest_context(inode, &snap_size);
 458         if (snapc->seq > oldest->seq) {
 459                 dout("writepage %p page %p snapc %p not writeable - noop\n",
 460                      inode, page, snapc);
 461                 /* we should only noop if called by kswapd */
 462                 WARN_ON((current->flags & PF_MEMALLOC) == 0);
 463                 ceph_put_snap_context(oldest);
 464                 goto out;
 465         }
 466         ceph_put_snap_context(oldest);
 467
 468         /* is this a partial page at end of file? */
 469         if (snap_size)
 470                 i_size = snap_size;
 471         else
 472                 i_size = i_size_read(inode);
 473         if (i_size < page_off + len)
 474                 len = i_size - page_off;
 475
 476         dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
 477              inode, page, page->index, page_off, len, snapc);
 478
 479         writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
 480         if (writeback_stat >
 481             CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
 482                 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
 483
 484         set_page_writeback(page);
 485         err = ceph_osdc_writepages(osdc, ceph_vino(inode),
 486                                    &ci->i_layout, snapc,
 487                                    page_off, len,
 488                                    ci->i_truncate_seq, ci->i_truncate_size,
 489                                    &inode->i_mtime, &page, 1);
 490         if (err < 0) {
 491                 dout("writepage setting page/mapping error %d %p\n", err, page);
 492                 SetPageError(page);
 493                 mapping_set_error(&inode->i_data, err);
 494                 if (wbc)
 495                         wbc->pages_skipped++;
 496         } else {
 497                 dout("writepage cleaned page %p\n", page);
 498                 err = 0;  /* vfs expects us to return 0 */
 499         }
 500         page->private = 0;
 501         ClearPagePrivate(page);
 502         end_page_writeback(page);
 503         ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 504         ceph_put_snap_context(snapc);  /* page's reference */
 505 out:
 506         return err;
 507 }
 508
 509 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 510 {
 511         int err;
 512         struct inode *inode = page->mapping->host;
 513         BUG_ON(!inode);
 514         ihold(inode);
 515         err = writepage_nounlock(page, wbc);
 516         unlock_page(page);
 517         iput(inode);
 518         return err;
 519 }
 520
 521
 522 /*
 523  * lame release_pages helper.  release_pages() isn't exported to
 524  * modules.
 525  */
 526 static void ceph_release_pages(struct page **pages, int num)
 527 {
 528         struct pagevec pvec;
 529         int i;
 530
 531         pagevec_init(&pvec, 0);
 532         for (i = 0; i < num; i++) {
 533                 if (pagevec_add(&pvec, pages[i]) == 0)
 534                         pagevec_release(&pvec);
 535         }
 536         pagevec_release(&pvec);
 537 }
 538
 539
 540 /*
 541  * async writeback completion handler.
 542  *
 543  * If we get an error, set the mapping error bit, but not the individual
 544  * page error bits.
 545  */
 546 static void writepages_finish(struct ceph_osd_request *req,
 547                               struct ceph_msg *msg)
 548 {
 549         struct inode *inode = req->r_inode;
 550         struct ceph_inode_info *ci = ceph_inode(inode);
 551         unsigned wrote;
 552         struct page *page;
 553         int i;
 554         struct ceph_snap_context *snapc = req->r_snapc;
 555         struct address_space *mapping = inode->i_mapping;
 556         int rc = req->r_result;
 557         u64 bytes = le64_to_cpu(req->r_request_ops[0].extent.length);
 558         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 559         long writeback_stat;
 560         unsigned issued = ceph_caps_issued(ci);
 561
 562         if (rc >= 0) {
 563                 /*
 564                  * Assume we wrote the pages we originally sent.  The
 565                  * osd might reply with fewer pages if our writeback
 566                  * raced with a truncation and was adjusted at the osd,
 567                  * so don't believe the reply.
 568                  */
 569                 wrote = req->r_num_pages;
 570         } else {
 571                 wrote = 0;
 572                 mapping_set_error(mapping, rc);
 573         }
 574         dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
 575              inode, rc, bytes, wrote);
 576
 577         /* clean all pages */
 578         for (i = 0; i < req->r_num_pages; i++) {
 579                 page = req->r_pages[i];
 580                 BUG_ON(!page);
 581                 WARN_ON(!PageUptodate(page));
 582
 583                 writeback_stat =
 584                         atomic_long_dec_return(&fsc->writeback_count);
 585                 if (writeback_stat <
 586                     CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
 587                         clear_bdi_congested(&fsc->backing_dev_info,
 588                                             BLK_RW_ASYNC);
 589
 590                 ceph_put_snap_context(page_snap_context(page));
 591                 page->private = 0;
 592                 ClearPagePrivate(page);
 593                 dout("unlocking %d %p\n", i, page);
 594                 end_page_writeback(page);
 595
 596                 /*
 597                  * We lost the cache cap, need to truncate the page before
 598                  * it is unlocked, otherwise we'd truncate it later in the
 599                  * page truncation thread, possibly losing some data that
 600                  * raced its way in
 601                  */
 602                 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
 603                         generic_error_remove_page(inode->i_mapping, page);
 604
 605                 unlock_page(page);
 606         }
 607         dout("%p wrote+cleaned %d pages\n", inode, wrote);
 608         ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
 609
 610         ceph_release_pages(req->r_pages, req->r_num_pages);
 611         if (req->r_pages_from_pool)
 612                 mempool_free(req->r_pages,
 613                              ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
 614         else
 615                 kfree(req->r_pages);
 616         ceph_osdc_put_request(req);
 617 }
 618
 619 /*
 620  * allocate a page vec, either directly, or if necessary, via a the
 621  * mempool.  we avoid the mempool if we can because req->r_num_pages
 622  * may be less than the maximum write size.
 623  */
 624 static void alloc_page_vec(struct ceph_fs_client *fsc,
 625                            struct ceph_osd_request *req)
 626 {
 627         req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
 628                                GFP_NOFS);
 629         if (!req->r_pages) {
 630                 req->r_pages = mempool_alloc(fsc->wb_pagevec_pool, GFP_NOFS);
 631                 req->r_pages_from_pool = 1;
 632                 WARN_ON(!req->r_pages);
 633         }
 634 }
 635
 636 /*
 637  * initiate async writeback
 638  */
 639 static int ceph_writepages_start(struct address_space *mapping,
 640                                  struct writeback_control *wbc)
 641 {
 642         struct inode *inode = mapping->host;
 643         struct ceph_inode_info *ci = ceph_inode(inode);
 644         struct ceph_fs_client *fsc;
 645         pgoff_t index, start, end;
 646         int range_whole = 0;
 647         int should_loop = 1;
 648         pgoff_t max_pages = 0, max_pages_ever = 0;
 649         struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
 650         struct pagevec pvec;
 651         int done = 0;
 652         int rc = 0;
 653         unsigned wsize = 1 << inode->i_blkbits;
 654         struct ceph_osd_request *req = NULL;
 655         int do_sync;
 656         u64 snap_size = 0;
 657
 658         /*
 659          * Include a 'sync' in the OSD request if this is a data
 660          * integrity write (e.g., O_SYNC write or fsync()), or if our
 661          * cap is being revoked.
 662          */
 663         do_sync = wbc->sync_mode == WB_SYNC_ALL;
 664         if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
 665                 do_sync = 1;
 666         dout("writepages_start %p dosync=%d (mode=%s)\n",
 667              inode, do_sync,
 668              wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
 669              (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
 670
 671         fsc = ceph_inode_to_client(inode);
 672         if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
 673                 pr_warning("writepage_start %p on forced umount\n", inode);
 674                 return -EIO; /* we're in a forced umount, don't write! */
 675         }
 676         if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
 677                 wsize = fsc->mount_options->wsize;
 678         if (wsize < PAGE_CACHE_SIZE)
 679                 wsize = PAGE_CACHE_SIZE;
 680         max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
 681
 682         pagevec_init(&pvec, 0);
 683
 684         /* where to start/end? */
 685         if (wbc->range_cyclic) {
 686                 start = mapping->writeback_index; /* Start from prev offset */
 687                 end = -1;
 688                 dout(" cyclic, start at %lu\n", start);
 689         } else {
 690                 start = wbc->range_start >> PAGE_CACHE_SHIFT;
 691                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
 692                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 693                         range_whole = 1;
 694                 should_loop = 0;
 695                 dout(" not cyclic, %lu to %lu\n", start, end);
 696         }
 697         index = start;
 698
 699 retry:
 700         /* find oldest snap context with dirty data */
 701         ceph_put_snap_context(snapc);
 702         snapc = get_oldest_context(inode, &snap_size);
 703         if (!snapc) {
 704                 /* hmm, why does writepages get called when there
 705                    is no dirty data? */
 706                 dout(" no snap context with dirty data?\n");
 707                 goto out;
 708         }
 709         dout(" oldest snapc is %p seq %lld (%d snaps)\n",
 710              snapc, snapc->seq, snapc->num_snaps);
 711         if (last_snapc && snapc != last_snapc) {
 712                 /* if we switched to a newer snapc, restart our scan at the
 713                  * start of the original file range. */
 714                 dout("  snapc differs from last pass, restarting at %lu\n",
 715                      index);
 716                 index = start;
 717         }
 718         last_snapc = snapc;
 719
 720         while (!done && index <= end) {
 721                 unsigned i;
 722                 int first;
 723                 pgoff_t next;
 724                 int pvec_pages, locked_pages;
 725                 struct page *page;
 726                 int want;
 727                 u64 offset, len;
 728                 long writeback_stat;
 729
 730                 next = 0;
 731                 locked_pages = 0;
 732                 max_pages = max_pages_ever;
 733
 734 get_more_pages:
 735                 first = -1;
 736                 want = min(end - index,
 737                            min((pgoff_t)PAGEVEC_SIZE,
 738                                max_pages - (pgoff_t)locked_pages) - 1)
 739                         + 1;
 740                 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 741                                                 PAGECACHE_TAG_DIRTY,
 742                                                 want);
 743                 dout("pagevec_lookup_tag got %d\n", pvec_pages);
 744                 if (!pvec_pages && !locked_pages)
 745                         break;
 746                 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
 747                         page = pvec.pages[i];
 748                         dout("? %p idx %lu\n", page, page->index);
 749                         if (locked_pages == 0)
 750                                 lock_page(page);  /* first page */
 751                         else if (!trylock_page(page))
 752                                 break;
 753
 754                         /* only dirty pages, or our accounting breaks */
 755                         if (unlikely(!PageDirty(page)) ||
 756                             unlikely(page->mapping != mapping)) {
 757                                 dout("!dirty or !mapping %p\n", page);
 758                                 unlock_page(page);
 759                                 break;
 760                         }
 761                         if (!wbc->range_cyclic && page->index > end) {
 762                                 dout("end of range %p\n", page);
 763                                 done = 1;
 764                                 unlock_page(page);
 765                                 break;
 766                         }
 767                         if (next && (page->index != next)) {
 768                                 dout("not consecutive %p\n", page);
 769                                 unlock_page(page);
 770                                 break;
 771                         }
 772                         if (wbc->sync_mode != WB_SYNC_NONE) {
 773                                 dout("waiting on writeback %p\n", page);
 774                                 wait_on_page_writeback(page);
 775                         }
 776                         if ((snap_size && page_offset(page) > snap_size) ||
 777                             (!snap_size &&
 778                              page_offset(page) > i_size_read(inode))) {
 779                                 dout("%p page eof %llu\n", page, snap_size ?
 780                                      snap_size : i_size_read(inode));
 781                                 done = 1;
 782                                 unlock_page(page);
 783                                 break;
 784                         }
 785                         if (PageWriteback(page)) {
 786                                 dout("%p under writeback\n", page);
 787                                 unlock_page(page);
 788                                 break;
 789                         }
 790
 791                         /* only if matching snap context */
 792                         pgsnapc = page_snap_context(page);
 793                         if (pgsnapc->seq > snapc->seq) {
 794                                 dout("page snapc %p %lld > oldest %p %lld\n",
 795                                      pgsnapc, pgsnapc->seq, snapc, snapc->seq);
 796                                 unlock_page(page);
 797                                 if (!locked_pages)
 798                                         continue; /* keep looking for snap */
 799                                 break;
 800                         }
 801
 802                         if (!clear_page_dirty_for_io(page)) {
 803                                 dout("%p !clear_page_dirty_for_io\n", page);
 804                                 unlock_page(page);
 805                                 break;
 806                         }
 807
 808                         /* ok */
 809                         if (locked_pages == 0) {
 810                                 /* prepare async write request */
 811                                 offset = (u64) page_offset(page);
 812                                 len = wsize;
 813                                 req = ceph_osdc_new_request(&fsc->client->osdc,
 814                                             &ci->i_layout,
 815                                             ceph_vino(inode),
 816                                             offset, &len,
 817                                             CEPH_OSD_OP_WRITE,
 818                                             CEPH_OSD_FLAG_WRITE |
 819                                                     CEPH_OSD_FLAG_ONDISK,
 820                                             snapc, do_sync,
 821                                             ci->i_truncate_seq,
 822                                             ci->i_truncate_size,
 823                                             &inode->i_mtime, true, 0);
 824
 825                                 if (IS_ERR(req)) {
 826                                         rc = PTR_ERR(req);
 827                                         unlock_page(page);
 828                                         break;
 829                                 }
 830
 831                                 max_pages = req->r_num_pages;
 832
 833                                 alloc_page_vec(fsc, req);
 834                                 req->r_callback = writepages_finish;
 835                                 req->r_inode = inode;
 836                         }
 837
 838                         /* note position of first page in pvec */
 839                         if (first < 0)
 840                                 first = i;
 841                         dout("%p will write page %p idx %lu\n",
 842                              inode, page, page->index);
 843
 844                         writeback_stat =
 845                                atomic_long_inc_return(&fsc->writeback_count);
 846                         if (writeback_stat > CONGESTION_ON_THRESH(
 847                                     fsc->mount_options->congestion_kb)) {
 848                                 set_bdi_congested(&fsc->backing_dev_info,
 849                                                   BLK_RW_ASYNC);
 850                         }
 851
 852                         set_page_writeback(page);
 853                         req->r_pages[locked_pages] = page;
 854                         locked_pages++;
 855                         next = page->index + 1;
 856                 }
 857
 858                 /* did we get anything? */
 859                 if (!locked_pages)
 860                         goto release_pvec_pages;
 861                 if (i) {
 862                         int j;
 863                         BUG_ON(!locked_pages || first < 0);
 864
 865                         if (pvec_pages && i == pvec_pages &&
 866                             locked_pages < max_pages) {
 867                                 dout("reached end pvec, trying for more\n");
 868                                 pagevec_reinit(&pvec);
 869                                 goto get_more_pages;
 870                         }
 871
 872                         /* shift unused pages over in the pvec...  we
 873                          * will need to release them below. */
 874                         for (j = i; j < pvec_pages; j++) {
 875                                 dout(" pvec leftover page %p\n",
 876                                      pvec.pages[j]);
 877                                 pvec.pages[j-i+first] = pvec.pages[j];
 878                         }
 879                         pvec.nr -= i-first;
 880                 }
 881
 882                 /* submit the write */
 883                 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
 884                 len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
 885                           (u64)locked_pages << PAGE_CACHE_SHIFT);
 886                 dout("writepages got %d pages at %llu~%llu\n",
 887                      locked_pages, offset, len);
 888
 889                 /* revise final length, page count */
 890                 req->r_num_pages = locked_pages;
 891                 req->r_request_ops[0].extent.length = cpu_to_le64(len);
 892                 req->r_request_ops[0].payload_len = cpu_to_le32(len);
 893                 req->r_request->hdr.data_len = cpu_to_le32(len);
 894
 895                 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
 896                 BUG_ON(rc);
 897                 req = NULL;
 898
 899                 /* continue? */
 900                 index = next;
 901                 wbc->nr_to_write -= locked_pages;
 902                 if (wbc->nr_to_write <= 0)
 903                         done = 1;
 904
 905 release_pvec_pages:
 906                 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
 907                      pvec.nr ? pvec.pages[0] : NULL);
 908                 pagevec_release(&pvec);
 909
 910                 if (locked_pages && !done)
 911                         goto retry;
 912         }
 913
 914         if (should_loop && !done) {
 915                 /* more to do; loop back to beginning of file */
 916                 dout("writepages looping back to beginning of file\n");
 917                 should_loop = 0;
 918                 index = 0;
 919                 goto retry;
 920         }
 921
 922         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 923                 mapping->writeback_index = index;
 924
 925 out:
 926         if (req)
 927                 ceph_osdc_put_request(req);
 928         ceph_put_snap_context(snapc);
 929         dout("writepages done, rc = %d\n", rc);
 930         return rc;
 931 }
 932
 933
 934
 935 /*
 936  * See if a given @snapc is either writeable, or already written.
 937  */
 938 static int context_is_writeable_or_written(struct inode *inode,
 939                                            struct ceph_snap_context *snapc)
 940 {
 941         struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
 942         int ret = !oldest || snapc->seq <= oldest->seq;
 943
 944         ceph_put_snap_context(oldest);
 945         return ret;
 946 }
 947
 948 /*
 949  * We are only allowed to write into/dirty the page if the page is
 950  * clean, or already dirty within the same snap context.
 951  *
 952  * called with page locked.
 953  * return success with page locked,
 954  * or any failure (incl -EAGAIN) with page unlocked.
 955  */
 956 static int ceph_update_writeable_page(struct file *file,
 957                             loff_t pos, unsigned len,
 958                             struct page *page)
 959 {
 960         struct inode *inode = file_inode(file);
 961         struct ceph_inode_info *ci = ceph_inode(inode);
 962         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
 963         loff_t page_off = pos & PAGE_CACHE_MASK;
 964         int pos_in_page = pos & ~PAGE_CACHE_MASK;
 965         int end_in_page = pos_in_page + len;
 966         loff_t i_size;
 967         int r;
 968         struct ceph_snap_context *snapc, *oldest;
 969
 970 retry_locked:
 971         /* writepages currently holds page lock, but if we change that later, */
 972         wait_on_page_writeback(page);
 973
 974         /* check snap context */
 975         BUG_ON(!ci->i_snap_realm);
 976         down_read(&mdsc->snap_rwsem);
 977         BUG_ON(!ci->i_snap_realm->cached_context);
 978         snapc = page_snap_context(page);
 979         if (snapc && snapc != ci->i_head_snapc) {
 980                 /*
 981                  * this page is already dirty in another (older) snap
 982                  * context!  is it writeable now?
 983                  */
 984                 oldest = get_oldest_context(inode, NULL);
 985                 up_read(&mdsc->snap_rwsem);
 986
 987                 if (snapc->seq > oldest->seq) {
 988                         ceph_put_snap_context(oldest);
 989                         dout(" page %p snapc %p not current or oldest\n",
 990                              page, snapc);
 991                         /*
 992                          * queue for writeback, and wait for snapc to
 993                          * be writeable or written
 994                          */
 995                         snapc = ceph_get_snap_context(snapc);
 996                         unlock_page(page);
 997                         ceph_queue_writeback(inode);
 998                         r = wait_event_interruptible(ci->i_cap_wq,
 999                                context_is_writeable_or_written(inode, snapc));
1000                         ceph_put_snap_context(snapc);
1001                         if (r == -ERESTARTSYS)
1002                                 return r;
1003                         return -EAGAIN;
1004                 }
1005                 ceph_put_snap_context(oldest);
1006
1007                 /* yay, writeable, do it now (without dropping page lock) */
1008                 dout(" page %p snapc %p not current, but oldest\n",
1009                      page, snapc);
1010                 if (!clear_page_dirty_for_io(page))
1011                         goto retry_locked;
1012                 r = writepage_nounlock(page, NULL);
1013                 if (r < 0)
1014                         goto fail_nosnap;
1015                 goto retry_locked;
1016         }
1017
1018         if (PageUptodate(page)) {
1019                 dout(" page %p already uptodate\n", page);
1020                 return 0;
1021         }
1022
1023         /* full page? */
1024         if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
1025                 return 0;
1026
1027         /* past end of file? */
1028         i_size = inode->i_size;   /* caller holds i_mutex */
1029
1030         if (i_size + len > inode->i_sb->s_maxbytes) {
1031                 /* file is too big */
1032                 r = -EINVAL;
1033                 goto fail;
1034         }
1035
1036         if (page_off >= i_size ||
1037             (pos_in_page == 0 && (pos+len) >= i_size &&
1038              end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1039                 dout(" zeroing %p 0 - %d and %d - %d\n",
1040                      page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1041                 zero_user_segments(page,
1042                                    0, pos_in_page,
1043                                    end_in_page, PAGE_CACHE_SIZE);
1044                 return 0;
1045         }
1046
1047         /* we need to read it. */
1048         up_read(&mdsc->snap_rwsem);
1049         r = readpage_nounlock(file, page);
1050         if (r < 0)
1051                 goto fail_nosnap;
1052         goto retry_locked;
1053
1054 fail:
1055         up_read(&mdsc->snap_rwsem);
1056 fail_nosnap:
1057         unlock_page(page);
1058         return r;
1059 }
1060
1061 /*
1062  * We are only allowed to write into/dirty the page if the page is
1063  * clean, or already dirty within the same snap context.
1064  */
1065 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1066                             loff_t pos, unsigned len, unsigned flags,
1067                             struct page **pagep, void **fsdata)
1068 {
1069         struct inode *inode = file_inode(file);
1070         struct ceph_inode_info *ci = ceph_inode(inode);
1071         struct ceph_file_info *fi = file->private_data;
1072         struct page *page;
1073         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1074         int r, want, got = 0;
1075
1076         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1077                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1078         else
1079                 want = CEPH_CAP_FILE_BUFFER;
1080
1081         dout("write_begin %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
1082              inode, ceph_vinop(inode), pos, len, inode->i_size);
1083         r = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos+len);
1084         if (r < 0)
1085                 return r;
1086         dout("write_begin %p %llx.%llx %llu~%u  got cap refs on %s\n",
1087              inode, ceph_vinop(inode), pos, len, ceph_cap_string(got));
1088         if (!(got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO))) {
1089                 ceph_put_cap_refs(ci, got);
1090                 return -EAGAIN;
1091         }
1092
1093         do {
1094                 /* get a page */
1095                 page = grab_cache_page_write_begin(mapping, index, 0);
1096                 if (!page) {
1097                         r = -ENOMEM;
1098                         break;
1099                 }
1100
1101                 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1102                      inode, page, (int)pos, (int)len);
1103
1104                 r = ceph_update_writeable_page(file, pos, len, page);
1105                 if (r)
1106                         page_cache_release(page);
1107         } while (r == -EAGAIN);
1108
1109         if (r) {
1110                 ceph_put_cap_refs(ci, got);
1111         } else {
1112                 *pagep = page;
1113                 *(int *)fsdata = got;
1114         }
1115         return r;
1116 }
1117
1118 /*
1119  * we don't do anything in here that simple_write_end doesn't do
1120  * except adjust dirty page accounting and drop read lock on
1121  * mdsc->snap_rwsem.
1122  */
1123 static int ceph_write_end(struct file *file, struct address_space *mapping,
1124                           loff_t pos, unsigned len, unsigned copied,
1125                           struct page *page, void *fsdata)
1126 {
1127         struct inode *inode = file_inode(file);
1128         struct ceph_inode_info *ci = ceph_inode(inode);
1129         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1130         struct ceph_mds_client *mdsc = fsc->mdsc;
1131         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1132         int check_cap = 0;
1133         int got = (unsigned long)fsdata;
1134
1135         dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1136              inode, page, (int)pos, (int)copied, (int)len);
1137
1138         /* zero the stale part of the page if we did a short copy */
1139         if (copied < len)
1140                 zero_user_segment(page, from+copied, len);
1141
1142         /* did file size increase? */
1143         /* (no need for i_size_read(); we caller holds i_mutex */
1144         if (pos+copied > inode->i_size)
1145                 check_cap = ceph_inode_set_size(inode, pos+copied);
1146
1147         if (!PageUptodate(page))
1148                 SetPageUptodate(page);
1149
1150         set_page_dirty(page);
1151
1152         unlock_page(page);
1153         up_read(&mdsc->snap_rwsem);
1154         page_cache_release(page);
1155
1156         if (copied > 0) {
1157                 int dirty;
1158                 spin_lock(&ci->i_ceph_lock);
1159                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
1160                 spin_unlock(&ci->i_ceph_lock);
1161                 if (dirty)
1162                         __mark_inode_dirty(inode, dirty);
1163         }
1164
1165         dout("write_end %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
1166              inode, ceph_vinop(inode), pos, len, ceph_cap_string(got));
1167         ceph_put_cap_refs(ci, got);
1168
1169         if (check_cap)
1170                 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1171
1172         return copied;
1173 }
1174
1175 /*
1176  * we set .direct_IO to indicate direct io is supported, but since we
1177  * intercept O_DIRECT reads and writes early, this function should
1178  * never get called.
1179  */
1180 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1181                               const struct iovec *iov,
1182                               loff_t pos, unsigned long nr_segs)
1183 {
1184         WARN_ON(1);
1185         return -EINVAL;
1186 }
1187
1188 const struct address_space_operations ceph_aops = {
1189         .readpage = ceph_readpage,
1190         .readpages = ceph_readpages,
1191         .writepage = ceph_writepage,
1192         .writepages = ceph_writepages_start,
1193         .write_begin = ceph_write_begin,
1194         .write_end = ceph_write_end,
1195         .set_page_dirty = ceph_set_page_dirty,
1196         .invalidatepage = ceph_invalidatepage,
1197         .releasepage = ceph_releasepage,
1198         .direct_IO = ceph_direct_io,
1199 };
1200
1201
1202 /*
1203  * vm ops
1204  */
1205
1206 /*
1207  * Reuse write_begin here for simplicity.
1208  */
1209 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1210 {
1211         struct inode *inode = file_inode(vma->vm_file);
1212         struct page *page = vmf->page;
1213         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1214         loff_t off = page_offset(page);
1215         loff_t size, len;
1216         int ret;
1217
1218         /* Update time before taking page lock */
1219         file_update_time(vma->vm_file);
1220
1221         size = i_size_read(inode);
1222         if (off + PAGE_CACHE_SIZE <= size)
1223                 len = PAGE_CACHE_SIZE;
1224         else
1225                 len = size & ~PAGE_CACHE_MASK;
1226
1227         dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1228              off, len, page, page->index);
1229
1230         lock_page(page);
1231
1232         ret = VM_FAULT_NOPAGE;
1233         if ((off > size) ||
1234             (page->mapping != inode->i_mapping))
1235                 goto out;
1236
1237         ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1238         if (ret == 0) {
1239                 /* success.  we'll keep the page locked. */
1240                 set_page_dirty(page);
1241                 up_read(&mdsc->snap_rwsem);
1242                 ret = VM_FAULT_LOCKED;
1243         } else {
1244                 if (ret == -ENOMEM)
1245                         ret = VM_FAULT_OOM;
1246                 else
1247                         ret = VM_FAULT_SIGBUS;
1248         }
1249 out:
1250         dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1251         if (ret != VM_FAULT_LOCKED)
1252                 unlock_page(page);
1253         return ret;
1254 }
1255
1256 static struct vm_operations_struct ceph_vmops = {
1257         .fault          = filemap_fault,
1258         .page_mkwrite   = ceph_page_mkwrite,
1259         .remap_pages    = generic_file_remap_pages,
1260 };
1261
1262 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1263 {
1264         struct address_space *mapping = file->f_mapping;
1265
1266         if (!mapping->a_ops->readpage)
1267                 return -ENOEXEC;
1268         file_accessed(file);
1269         vma->vm_ops = &ceph_vmops;
1270         return 0;
1271 }