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TOMOYO Linux Cross Reference
Linux/fs/ceph/addr.c

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  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 int offset,
147                                 unsigned int length)
148 {
149         struct inode *inode;
150         struct ceph_inode_info *ci;
151         struct ceph_snap_context *snapc = page_snap_context(page);
152 
153         BUG_ON(!PageLocked(page));
154         BUG_ON(!PagePrivate(page));
155         BUG_ON(!page->mapping);
156 
157         inode = page->mapping->host;
158 
159         /*
160          * We can get non-dirty pages here due to races between
161          * set_page_dirty and truncate_complete_page; just spit out a
162          * warning, in case we end up with accounting problems later.
163          */
164         if (!PageDirty(page))
165                 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
166 
167         if (offset == 0 && length == PAGE_CACHE_SIZE)
168                 ClearPageChecked(page);
169 
170         ci = ceph_inode(inode);
171         if (offset == 0 && length == PAGE_CACHE_SIZE) {
172                 dout("%p invalidatepage %p idx %lu full dirty page\n",
173                      inode, page, page->index);
174                 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
175                 ceph_put_snap_context(snapc);
176                 page->private = 0;
177                 ClearPagePrivate(page);
178         } else {
179                 dout("%p invalidatepage %p idx %lu partial dirty page %u(%u)\n",
180                      inode, page, page->index, offset, length);
181         }
182 }
183 
184 /* just a sanity check */
185 static int ceph_releasepage(struct page *page, gfp_t g)
186 {
187         struct inode *inode = page->mapping ? page->mapping->host : NULL;
188         dout("%p releasepage %p idx %lu\n", inode, page, page->index);
189         WARN_ON(PageDirty(page));
190         WARN_ON(PagePrivate(page));
191         return 0;
192 }
193 
194 /*
195  * read a single page, without unlocking it.
196  */
197 static int readpage_nounlock(struct file *filp, struct page *page)
198 {
199         struct inode *inode = file_inode(filp);
200         struct ceph_inode_info *ci = ceph_inode(inode);
201         struct ceph_osd_client *osdc = 
202                 &ceph_inode_to_client(inode)->client->osdc;
203         int err = 0;
204         u64 len = PAGE_CACHE_SIZE;
205 
206         dout("readpage inode %p file %p page %p index %lu\n",
207              inode, filp, page, page->index);
208         err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
209                                   (u64) page_offset(page), &len,
210                                   ci->i_truncate_seq, ci->i_truncate_size,
211                                   &page, 1, 0);
212         if (err == -ENOENT)
213                 err = 0;
214         if (err < 0) {
215                 SetPageError(page);
216                 goto out;
217         } else if (err < PAGE_CACHE_SIZE) {
218                 /* zero fill remainder of page */
219                 zero_user_segment(page, err, PAGE_CACHE_SIZE);
220         }
221         SetPageUptodate(page);
222 
223 out:
224         return err < 0 ? err : 0;
225 }
226 
227 static int ceph_readpage(struct file *filp, struct page *page)
228 {
229         int r = readpage_nounlock(filp, page);
230         unlock_page(page);
231         return r;
232 }
233 
234 /*
235  * Finish an async read(ahead) op.
236  */
237 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
238 {
239         struct inode *inode = req->r_inode;
240         struct ceph_osd_data *osd_data;
241         int rc = req->r_result;
242         int bytes = le32_to_cpu(msg->hdr.data_len);
243         int num_pages;
244         int i;
245 
246         dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
247 
248         /* unlock all pages, zeroing any data we didn't read */
249         osd_data = osd_req_op_extent_osd_data(req, 0);
250         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
251         num_pages = calc_pages_for((u64)osd_data->alignment,
252                                         (u64)osd_data->length);
253         for (i = 0; i < num_pages; i++) {
254                 struct page *page = osd_data->pages[i];
255 
256                 if (bytes < (int)PAGE_CACHE_SIZE) {
257                         /* zero (remainder of) page */
258                         int s = bytes < 0 ? 0 : bytes;
259                         zero_user_segment(page, s, PAGE_CACHE_SIZE);
260                 }
261                 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
262                      page->index);
263                 flush_dcache_page(page);
264                 SetPageUptodate(page);
265                 unlock_page(page);
266                 page_cache_release(page);
267                 bytes -= PAGE_CACHE_SIZE;
268         }
269         kfree(osd_data->pages);
270 }
271 
272 static void ceph_unlock_page_vector(struct page **pages, int num_pages)
273 {
274         int i;
275 
276         for (i = 0; i < num_pages; i++)
277                 unlock_page(pages[i]);
278 }
279 
280 /*
281  * start an async read(ahead) operation.  return nr_pages we submitted
282  * a read for on success, or negative error code.
283  */
284 static int start_read(struct inode *inode, struct list_head *page_list, int max)
285 {
286         struct ceph_osd_client *osdc =
287                 &ceph_inode_to_client(inode)->client->osdc;
288         struct ceph_inode_info *ci = ceph_inode(inode);
289         struct page *page = list_entry(page_list->prev, struct page, lru);
290         struct ceph_vino vino;
291         struct ceph_osd_request *req;
292         u64 off;
293         u64 len;
294         int i;
295         struct page **pages;
296         pgoff_t next_index;
297         int nr_pages = 0;
298         int ret;
299 
300         off = (u64) page_offset(page);
301 
302         /* count pages */
303         next_index = page->index;
304         list_for_each_entry_reverse(page, page_list, lru) {
305                 if (page->index != next_index)
306                         break;
307                 nr_pages++;
308                 next_index++;
309                 if (max && nr_pages == max)
310                         break;
311         }
312         len = nr_pages << PAGE_CACHE_SHIFT;
313         dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
314              off, len);
315         vino = ceph_vino(inode);
316         req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
317                                     1, CEPH_OSD_OP_READ,
318                                     CEPH_OSD_FLAG_READ, NULL,
319                                     ci->i_truncate_seq, ci->i_truncate_size,
320                                     false);
321         if (IS_ERR(req))
322                 return PTR_ERR(req);
323 
324         /* build page vector */
325         nr_pages = calc_pages_for(0, len);
326         pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
327         ret = -ENOMEM;
328         if (!pages)
329                 goto out;
330         for (i = 0; i < nr_pages; ++i) {
331                 page = list_entry(page_list->prev, struct page, lru);
332                 BUG_ON(PageLocked(page));
333                 list_del(&page->lru);
334                 
335                 dout("start_read %p adding %p idx %lu\n", inode, page,
336                      page->index);
337                 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
338                                           GFP_NOFS)) {
339                         page_cache_release(page);
340                         dout("start_read %p add_to_page_cache failed %p\n",
341                              inode, page);
342                         nr_pages = i;
343                         goto out_pages;
344                 }
345                 pages[i] = page;
346         }
347         osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
348         req->r_callback = finish_read;
349         req->r_inode = inode;
350 
351         ceph_osdc_build_request(req, off, NULL, vino.snap, NULL);
352 
353         dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
354         ret = ceph_osdc_start_request(osdc, req, false);
355         if (ret < 0)
356                 goto out_pages;
357         ceph_osdc_put_request(req);
358         return nr_pages;
359 
360 out_pages:
361         ceph_unlock_page_vector(pages, nr_pages);
362         ceph_release_page_vector(pages, nr_pages);
363 out:
364         ceph_osdc_put_request(req);
365         return ret;
366 }
367 
368 
369 /*
370  * Read multiple pages.  Leave pages we don't read + unlock in page_list;
371  * the caller (VM) cleans them up.
372  */
373 static int ceph_readpages(struct file *file, struct address_space *mapping,
374                           struct list_head *page_list, unsigned nr_pages)
375 {
376         struct inode *inode = file_inode(file);
377         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
378         int rc = 0;
379         int max = 0;
380 
381         if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
382                 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
383                         >> PAGE_SHIFT;
384 
385         dout("readpages %p file %p nr_pages %d max %d\n", inode,
386                 file, nr_pages,
387              max);
388         while (!list_empty(page_list)) {
389                 rc = start_read(inode, page_list, max);
390                 if (rc < 0)
391                         goto out;
392                 BUG_ON(rc == 0);
393         }
394 out:
395         dout("readpages %p file %p ret %d\n", inode, file, rc);
396         return rc;
397 }
398 
399 /*
400  * Get ref for the oldest snapc for an inode with dirty data... that is, the
401  * only snap context we are allowed to write back.
402  */
403 static struct ceph_snap_context *get_oldest_context(struct inode *inode,
404                                                     u64 *snap_size)
405 {
406         struct ceph_inode_info *ci = ceph_inode(inode);
407         struct ceph_snap_context *snapc = NULL;
408         struct ceph_cap_snap *capsnap = NULL;
409 
410         spin_lock(&ci->i_ceph_lock);
411         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
412                 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
413                      capsnap->context, capsnap->dirty_pages);
414                 if (capsnap->dirty_pages) {
415                         snapc = ceph_get_snap_context(capsnap->context);
416                         if (snap_size)
417                                 *snap_size = capsnap->size;
418                         break;
419                 }
420         }
421         if (!snapc && ci->i_wrbuffer_ref_head) {
422                 snapc = ceph_get_snap_context(ci->i_head_snapc);
423                 dout(" head snapc %p has %d dirty pages\n",
424                      snapc, ci->i_wrbuffer_ref_head);
425         }
426         spin_unlock(&ci->i_ceph_lock);
427         return snapc;
428 }
429 
430 /*
431  * Write a single page, but leave the page locked.
432  *
433  * If we get a write error, set the page error bit, but still adjust the
434  * dirty page accounting (i.e., page is no longer dirty).
435  */
436 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
437 {
438         struct inode *inode;
439         struct ceph_inode_info *ci;
440         struct ceph_fs_client *fsc;
441         struct ceph_osd_client *osdc;
442         struct ceph_snap_context *snapc, *oldest;
443         loff_t page_off = page_offset(page);
444         long writeback_stat;
445         u64 truncate_size, snap_size = 0;
446         u32 truncate_seq;
447         int err = 0, len = PAGE_CACHE_SIZE;
448 
449         dout("writepage %p idx %lu\n", page, page->index);
450 
451         if (!page->mapping || !page->mapping->host) {
452                 dout("writepage %p - no mapping\n", page);
453                 return -EFAULT;
454         }
455         inode = page->mapping->host;
456         ci = ceph_inode(inode);
457         fsc = ceph_inode_to_client(inode);
458         osdc = &fsc->client->osdc;
459 
460         /* verify this is a writeable snap context */
461         snapc = page_snap_context(page);
462         if (snapc == NULL) {
463                 dout("writepage %p page %p not dirty?\n", inode, page);
464                 goto out;
465         }
466         oldest = get_oldest_context(inode, &snap_size);
467         if (snapc->seq > oldest->seq) {
468                 dout("writepage %p page %p snapc %p not writeable - noop\n",
469                      inode, page, snapc);
470                 /* we should only noop if called by kswapd */
471                 WARN_ON((current->flags & PF_MEMALLOC) == 0);
472                 ceph_put_snap_context(oldest);
473                 goto out;
474         }
475         ceph_put_snap_context(oldest);
476 
477         spin_lock(&ci->i_ceph_lock);
478         truncate_seq = ci->i_truncate_seq;
479         truncate_size = ci->i_truncate_size;
480         if (!snap_size)
481                 snap_size = i_size_read(inode);
482         spin_unlock(&ci->i_ceph_lock);
483 
484         /* is this a partial page at end of file? */
485         if (page_off >= snap_size) {
486                 dout("%p page eof %llu\n", page, snap_size);
487                 goto out;
488         }
489         if (snap_size < page_off + len)
490                 len = snap_size - page_off;
491 
492         dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
493              inode, page, page->index, page_off, len, snapc);
494 
495         writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
496         if (writeback_stat >
497             CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
498                 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
499 
500         set_page_writeback(page);
501         err = ceph_osdc_writepages(osdc, ceph_vino(inode),
502                                    &ci->i_layout, snapc,
503                                    page_off, len,
504                                    truncate_seq, truncate_size,
505                                    &inode->i_mtime, &page, 1);
506         if (err < 0) {
507                 dout("writepage setting page/mapping error %d %p\n", err, page);
508                 SetPageError(page);
509                 mapping_set_error(&inode->i_data, err);
510                 if (wbc)
511                         wbc->pages_skipped++;
512         } else {
513                 dout("writepage cleaned page %p\n", page);
514                 err = 0;  /* vfs expects us to return 0 */
515         }
516         page->private = 0;
517         ClearPagePrivate(page);
518         end_page_writeback(page);
519         ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
520         ceph_put_snap_context(snapc);  /* page's reference */
521 out:
522         return err;
523 }
524 
525 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
526 {
527         int err;
528         struct inode *inode = page->mapping->host;
529         BUG_ON(!inode);
530         ihold(inode);
531         err = writepage_nounlock(page, wbc);
532         unlock_page(page);
533         iput(inode);
534         return err;
535 }
536 
537 
538 /*
539  * lame release_pages helper.  release_pages() isn't exported to
540  * modules.
541  */
542 static void ceph_release_pages(struct page **pages, int num)
543 {
544         struct pagevec pvec;
545         int i;
546 
547         pagevec_init(&pvec, 0);
548         for (i = 0; i < num; i++) {
549                 if (pagevec_add(&pvec, pages[i]) == 0)
550                         pagevec_release(&pvec);
551         }
552         pagevec_release(&pvec);
553 }
554 
555 
556 /*
557  * async writeback completion handler.
558  *
559  * If we get an error, set the mapping error bit, but not the individual
560  * page error bits.
561  */
562 static void writepages_finish(struct ceph_osd_request *req,
563                               struct ceph_msg *msg)
564 {
565         struct inode *inode = req->r_inode;
566         struct ceph_inode_info *ci = ceph_inode(inode);
567         struct ceph_osd_data *osd_data;
568         unsigned wrote;
569         struct page *page;
570         int num_pages;
571         int i;
572         struct ceph_snap_context *snapc = req->r_snapc;
573         struct address_space *mapping = inode->i_mapping;
574         int rc = req->r_result;
575         u64 bytes = req->r_ops[0].extent.length;
576         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
577         long writeback_stat;
578         unsigned issued = ceph_caps_issued(ci);
579 
580         osd_data = osd_req_op_extent_osd_data(req, 0);
581         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
582         num_pages = calc_pages_for((u64)osd_data->alignment,
583                                         (u64)osd_data->length);
584         if (rc >= 0) {
585                 /*
586                  * Assume we wrote the pages we originally sent.  The
587                  * osd might reply with fewer pages if our writeback
588                  * raced with a truncation and was adjusted at the osd,
589                  * so don't believe the reply.
590                  */
591                 wrote = num_pages;
592         } else {
593                 wrote = 0;
594                 mapping_set_error(mapping, rc);
595         }
596         dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
597              inode, rc, bytes, wrote);
598 
599         /* clean all pages */
600         for (i = 0; i < num_pages; i++) {
601                 page = osd_data->pages[i];
602                 BUG_ON(!page);
603                 WARN_ON(!PageUptodate(page));
604 
605                 writeback_stat =
606                         atomic_long_dec_return(&fsc->writeback_count);
607                 if (writeback_stat <
608                     CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
609                         clear_bdi_congested(&fsc->backing_dev_info,
610                                             BLK_RW_ASYNC);
611 
612                 ceph_put_snap_context(page_snap_context(page));
613                 page->private = 0;
614                 ClearPagePrivate(page);
615                 dout("unlocking %d %p\n", i, page);
616                 end_page_writeback(page);
617 
618                 /*
619                  * We lost the cache cap, need to truncate the page before
620                  * it is unlocked, otherwise we'd truncate it later in the
621                  * page truncation thread, possibly losing some data that
622                  * raced its way in
623                  */
624                 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
625                         generic_error_remove_page(inode->i_mapping, page);
626 
627                 unlock_page(page);
628         }
629         dout("%p wrote+cleaned %d pages\n", inode, wrote);
630         ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc);
631 
632         ceph_release_pages(osd_data->pages, num_pages);
633         if (osd_data->pages_from_pool)
634                 mempool_free(osd_data->pages,
635                              ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
636         else
637                 kfree(osd_data->pages);
638         ceph_osdc_put_request(req);
639 }
640 
641 /*
642  * initiate async writeback
643  */
644 static int ceph_writepages_start(struct address_space *mapping,
645                                  struct writeback_control *wbc)
646 {
647         struct inode *inode = mapping->host;
648         struct ceph_inode_info *ci = ceph_inode(inode);
649         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
650         struct ceph_vino vino = ceph_vino(inode);
651         pgoff_t index, start, end;
652         int range_whole = 0;
653         int should_loop = 1;
654         pgoff_t max_pages = 0, max_pages_ever = 0;
655         struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
656         struct pagevec pvec;
657         int done = 0;
658         int rc = 0;
659         unsigned wsize = 1 << inode->i_blkbits;
660         struct ceph_osd_request *req = NULL;
661         int do_sync;
662         u64 truncate_size, snap_size;
663         u32 truncate_seq;
664 
665         /*
666          * Include a 'sync' in the OSD request if this is a data
667          * integrity write (e.g., O_SYNC write or fsync()), or if our
668          * cap is being revoked.
669          */
670         if ((wbc->sync_mode == WB_SYNC_ALL) ||
671                 ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
672                 do_sync = 1;
673         dout("writepages_start %p dosync=%d (mode=%s)\n",
674              inode, do_sync,
675              wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
676              (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
677 
678         if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
679                 pr_warning("writepage_start %p on forced umount\n", inode);
680                 return -EIO; /* we're in a forced umount, don't write! */
681         }
682         if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
683                 wsize = fsc->mount_options->wsize;
684         if (wsize < PAGE_CACHE_SIZE)
685                 wsize = PAGE_CACHE_SIZE;
686         max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
687 
688         pagevec_init(&pvec, 0);
689 
690         /* where to start/end? */
691         if (wbc->range_cyclic) {
692                 start = mapping->writeback_index; /* Start from prev offset */
693                 end = -1;
694                 dout(" cyclic, start at %lu\n", start);
695         } else {
696                 start = wbc->range_start >> PAGE_CACHE_SHIFT;
697                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
698                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
699                         range_whole = 1;
700                 should_loop = 0;
701                 dout(" not cyclic, %lu to %lu\n", start, end);
702         }
703         index = start;
704 
705 retry:
706         /* find oldest snap context with dirty data */
707         ceph_put_snap_context(snapc);
708         snap_size = 0;
709         snapc = get_oldest_context(inode, &snap_size);
710         if (!snapc) {
711                 /* hmm, why does writepages get called when there
712                    is no dirty data? */
713                 dout(" no snap context with dirty data?\n");
714                 goto out;
715         }
716         if (snap_size == 0)
717                 snap_size = i_size_read(inode);
718         dout(" oldest snapc is %p seq %lld (%d snaps)\n",
719              snapc, snapc->seq, snapc->num_snaps);
720 
721         spin_lock(&ci->i_ceph_lock);
722         truncate_seq = ci->i_truncate_seq;
723         truncate_size = ci->i_truncate_size;
724         if (!snap_size)
725                 snap_size = i_size_read(inode);
726         spin_unlock(&ci->i_ceph_lock);
727 
728         if (last_snapc && snapc != last_snapc) {
729                 /* if we switched to a newer snapc, restart our scan at the
730                  * start of the original file range. */
731                 dout("  snapc differs from last pass, restarting at %lu\n",
732                      index);
733                 index = start;
734         }
735         last_snapc = snapc;
736 
737         while (!done && index <= end) {
738                 int num_ops = do_sync ? 2 : 1;
739                 unsigned i;
740                 int first;
741                 pgoff_t next;
742                 int pvec_pages, locked_pages;
743                 struct page **pages = NULL;
744                 mempool_t *pool = NULL; /* Becomes non-null if mempool used */
745                 struct page *page;
746                 int want;
747                 u64 offset, len;
748                 long writeback_stat;
749 
750                 next = 0;
751                 locked_pages = 0;
752                 max_pages = max_pages_ever;
753 
754 get_more_pages:
755                 first = -1;
756                 want = min(end - index,
757                            min((pgoff_t)PAGEVEC_SIZE,
758                                max_pages - (pgoff_t)locked_pages) - 1)
759                         + 1;
760                 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
761                                                 PAGECACHE_TAG_DIRTY,
762                                                 want);
763                 dout("pagevec_lookup_tag got %d\n", pvec_pages);
764                 if (!pvec_pages && !locked_pages)
765                         break;
766                 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
767                         page = pvec.pages[i];
768                         dout("? %p idx %lu\n", page, page->index);
769                         if (locked_pages == 0)
770                                 lock_page(page);  /* first page */
771                         else if (!trylock_page(page))
772                                 break;
773 
774                         /* only dirty pages, or our accounting breaks */
775                         if (unlikely(!PageDirty(page)) ||
776                             unlikely(page->mapping != mapping)) {
777                                 dout("!dirty or !mapping %p\n", page);
778                                 unlock_page(page);
779                                 break;
780                         }
781                         if (!wbc->range_cyclic && page->index > end) {
782                                 dout("end of range %p\n", page);
783                                 done = 1;
784                                 unlock_page(page);
785                                 break;
786                         }
787                         if (next && (page->index != next)) {
788                                 dout("not consecutive %p\n", page);
789                                 unlock_page(page);
790                                 break;
791                         }
792                         if (wbc->sync_mode != WB_SYNC_NONE) {
793                                 dout("waiting on writeback %p\n", page);
794                                 wait_on_page_writeback(page);
795                         }
796                         if (page_offset(page) >= snap_size) {
797                                 dout("%p page eof %llu\n", page, snap_size);
798                                 done = 1;
799                                 unlock_page(page);
800                                 break;
801                         }
802                         if (PageWriteback(page)) {
803                                 dout("%p under writeback\n", page);
804                                 unlock_page(page);
805                                 break;
806                         }
807 
808                         /* only if matching snap context */
809                         pgsnapc = page_snap_context(page);
810                         if (pgsnapc->seq > snapc->seq) {
811                                 dout("page snapc %p %lld > oldest %p %lld\n",
812                                      pgsnapc, pgsnapc->seq, snapc, snapc->seq);
813                                 unlock_page(page);
814                                 if (!locked_pages)
815                                         continue; /* keep looking for snap */
816                                 break;
817                         }
818 
819                         if (!clear_page_dirty_for_io(page)) {
820                                 dout("%p !clear_page_dirty_for_io\n", page);
821                                 unlock_page(page);
822                                 break;
823                         }
824 
825                         /*
826                          * We have something to write.  If this is
827                          * the first locked page this time through,
828                          * allocate an osd request and a page array
829                          * that it will use.
830                          */
831                         if (locked_pages == 0) {
832                                 BUG_ON(pages);
833                                 /* prepare async write request */
834                                 offset = (u64)page_offset(page);
835                                 len = wsize;
836                                 req = ceph_osdc_new_request(&fsc->client->osdc,
837                                                         &ci->i_layout, vino,
838                                                         offset, &len, num_ops,
839                                                         CEPH_OSD_OP_WRITE,
840                                                         CEPH_OSD_FLAG_WRITE |
841                                                         CEPH_OSD_FLAG_ONDISK,
842                                                         snapc, truncate_seq,
843                                                         truncate_size, true);
844                                 if (IS_ERR(req)) {
845                                         rc = PTR_ERR(req);
846                                         unlock_page(page);
847                                         break;
848                                 }
849 
850                                 req->r_callback = writepages_finish;
851                                 req->r_inode = inode;
852 
853                                 max_pages = calc_pages_for(0, (u64)len);
854                                 pages = kmalloc(max_pages * sizeof (*pages),
855                                                 GFP_NOFS);
856                                 if (!pages) {
857                                         pool = fsc->wb_pagevec_pool;
858                                         pages = mempool_alloc(pool, GFP_NOFS);
859                                         BUG_ON(!pages);
860                                 }
861                         }
862 
863                         /* note position of first page in pvec */
864                         if (first < 0)
865                                 first = i;
866                         dout("%p will write page %p idx %lu\n",
867                              inode, page, page->index);
868 
869                         writeback_stat =
870                                atomic_long_inc_return(&fsc->writeback_count);
871                         if (writeback_stat > CONGESTION_ON_THRESH(
872                                     fsc->mount_options->congestion_kb)) {
873                                 set_bdi_congested(&fsc->backing_dev_info,
874                                                   BLK_RW_ASYNC);
875                         }
876 
877                         set_page_writeback(page);
878                         pages[locked_pages] = page;
879                         locked_pages++;
880                         next = page->index + 1;
881                 }
882 
883                 /* did we get anything? */
884                 if (!locked_pages)
885                         goto release_pvec_pages;
886                 if (i) {
887                         int j;
888                         BUG_ON(!locked_pages || first < 0);
889 
890                         if (pvec_pages && i == pvec_pages &&
891                             locked_pages < max_pages) {
892                                 dout("reached end pvec, trying for more\n");
893                                 pagevec_reinit(&pvec);
894                                 goto get_more_pages;
895                         }
896 
897                         /* shift unused pages over in the pvec...  we
898                          * will need to release them below. */
899                         for (j = i; j < pvec_pages; j++) {
900                                 dout(" pvec leftover page %p\n",
901                                      pvec.pages[j]);
902                                 pvec.pages[j-i+first] = pvec.pages[j];
903                         }
904                         pvec.nr -= i-first;
905                 }
906 
907                 /* Format the osd request message and submit the write */
908 
909                 offset = page_offset(pages[0]);
910                 len = min(snap_size - offset,
911                           (u64)locked_pages << PAGE_CACHE_SHIFT);
912                 dout("writepages got %d pages at %llu~%llu\n",
913                      locked_pages, offset, len);
914 
915                 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
916                                                         !!pool, false);
917 
918                 pages = NULL;   /* request message now owns the pages array */
919                 pool = NULL;
920 
921                 /* Update the write op length in case we changed it */
922 
923                 osd_req_op_extent_update(req, 0, len);
924 
925                 vino = ceph_vino(inode);
926                 ceph_osdc_build_request(req, offset, snapc, vino.snap,
927                                         &inode->i_mtime);
928 
929                 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
930                 BUG_ON(rc);
931                 req = NULL;
932 
933                 /* continue? */
934                 index = next;
935                 wbc->nr_to_write -= locked_pages;
936                 if (wbc->nr_to_write <= 0)
937                         done = 1;
938 
939 release_pvec_pages:
940                 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
941                      pvec.nr ? pvec.pages[0] : NULL);
942                 pagevec_release(&pvec);
943 
944                 if (locked_pages && !done)
945                         goto retry;
946         }
947 
948         if (should_loop && !done) {
949                 /* more to do; loop back to beginning of file */
950                 dout("writepages looping back to beginning of file\n");
951                 should_loop = 0;
952                 index = 0;
953                 goto retry;
954         }
955 
956         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
957                 mapping->writeback_index = index;
958 
959 out:
960         if (req)
961                 ceph_osdc_put_request(req);
962         ceph_put_snap_context(snapc);
963         dout("writepages done, rc = %d\n", rc);
964         return rc;
965 }
966 
967 
968 
969 /*
970  * See if a given @snapc is either writeable, or already written.
971  */
972 static int context_is_writeable_or_written(struct inode *inode,
973                                            struct ceph_snap_context *snapc)
974 {
975         struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
976         int ret = !oldest || snapc->seq <= oldest->seq;
977 
978         ceph_put_snap_context(oldest);
979         return ret;
980 }
981 
982 /*
983  * We are only allowed to write into/dirty the page if the page is
984  * clean, or already dirty within the same snap context.
985  *
986  * called with page locked.
987  * return success with page locked,
988  * or any failure (incl -EAGAIN) with page unlocked.
989  */
990 static int ceph_update_writeable_page(struct file *file,
991                             loff_t pos, unsigned len,
992                             struct page *page)
993 {
994         struct inode *inode = file_inode(file);
995         struct ceph_inode_info *ci = ceph_inode(inode);
996         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
997         loff_t page_off = pos & PAGE_CACHE_MASK;
998         int pos_in_page = pos & ~PAGE_CACHE_MASK;
999         int end_in_page = pos_in_page + len;
1000         loff_t i_size;
1001         int r;
1002         struct ceph_snap_context *snapc, *oldest;
1003 
1004 retry_locked:
1005         /* writepages currently holds page lock, but if we change that later, */
1006         wait_on_page_writeback(page);
1007 
1008         /* check snap context */
1009         BUG_ON(!ci->i_snap_realm);
1010         down_read(&mdsc->snap_rwsem);
1011         BUG_ON(!ci->i_snap_realm->cached_context);
1012         snapc = page_snap_context(page);
1013         if (snapc && snapc != ci->i_head_snapc) {
1014                 /*
1015                  * this page is already dirty in another (older) snap
1016                  * context!  is it writeable now?
1017                  */
1018                 oldest = get_oldest_context(inode, NULL);
1019                 up_read(&mdsc->snap_rwsem);
1020 
1021                 if (snapc->seq > oldest->seq) {
1022                         ceph_put_snap_context(oldest);
1023                         dout(" page %p snapc %p not current or oldest\n",
1024                              page, snapc);
1025                         /*
1026                          * queue for writeback, and wait for snapc to
1027                          * be writeable or written
1028                          */
1029                         snapc = ceph_get_snap_context(snapc);
1030                         unlock_page(page);
1031                         ceph_queue_writeback(inode);
1032                         r = wait_event_interruptible(ci->i_cap_wq,
1033                                context_is_writeable_or_written(inode, snapc));
1034                         ceph_put_snap_context(snapc);
1035                         if (r == -ERESTARTSYS)
1036                                 return r;
1037                         return -EAGAIN;
1038                 }
1039                 ceph_put_snap_context(oldest);
1040 
1041                 /* yay, writeable, do it now (without dropping page lock) */
1042                 dout(" page %p snapc %p not current, but oldest\n",
1043                      page, snapc);
1044                 if (!clear_page_dirty_for_io(page))
1045                         goto retry_locked;
1046                 r = writepage_nounlock(page, NULL);
1047                 if (r < 0)
1048                         goto fail_nosnap;
1049                 goto retry_locked;
1050         }
1051 
1052         if (PageUptodate(page)) {
1053                 dout(" page %p already uptodate\n", page);
1054                 return 0;
1055         }
1056 
1057         /* full page? */
1058         if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
1059                 return 0;
1060 
1061         /* past end of file? */
1062         i_size = inode->i_size;   /* caller holds i_mutex */
1063 
1064         if (i_size + len > inode->i_sb->s_maxbytes) {
1065                 /* file is too big */
1066                 r = -EINVAL;
1067                 goto fail;
1068         }
1069 
1070         if (page_off >= i_size ||
1071             (pos_in_page == 0 && (pos+len) >= i_size &&
1072              end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1073                 dout(" zeroing %p 0 - %d and %d - %d\n",
1074                      page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1075                 zero_user_segments(page,
1076                                    0, pos_in_page,
1077                                    end_in_page, PAGE_CACHE_SIZE);
1078                 return 0;
1079         }
1080 
1081         /* we need to read it. */
1082         up_read(&mdsc->snap_rwsem);
1083         r = readpage_nounlock(file, page);
1084         if (r < 0)
1085                 goto fail_nosnap;
1086         goto retry_locked;
1087 
1088 fail:
1089         up_read(&mdsc->snap_rwsem);
1090 fail_nosnap:
1091         unlock_page(page);
1092         return r;
1093 }
1094 
1095 /*
1096  * We are only allowed to write into/dirty the page if the page is
1097  * clean, or already dirty within the same snap context.
1098  */
1099 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1100                             loff_t pos, unsigned len, unsigned flags,
1101                             struct page **pagep, void **fsdata)
1102 {
1103         struct inode *inode = file_inode(file);
1104         struct page *page;
1105         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1106         int r;
1107 
1108         do {
1109                 /* get a page */
1110                 page = grab_cache_page_write_begin(mapping, index, 0);
1111                 if (!page)
1112                         return -ENOMEM;
1113                 *pagep = page;
1114 
1115                 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1116                      inode, page, (int)pos, (int)len);
1117 
1118                 r = ceph_update_writeable_page(file, pos, len, page);
1119         } while (r == -EAGAIN);
1120 
1121         return r;
1122 }
1123 
1124 /*
1125  * we don't do anything in here that simple_write_end doesn't do
1126  * except adjust dirty page accounting and drop read lock on
1127  * mdsc->snap_rwsem.
1128  */
1129 static int ceph_write_end(struct file *file, struct address_space *mapping,
1130                           loff_t pos, unsigned len, unsigned copied,
1131                           struct page *page, void *fsdata)
1132 {
1133         struct inode *inode = file_inode(file);
1134         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1135         struct ceph_mds_client *mdsc = fsc->mdsc;
1136         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1137         int check_cap = 0;
1138 
1139         dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1140              inode, page, (int)pos, (int)copied, (int)len);
1141 
1142         /* zero the stale part of the page if we did a short copy */
1143         if (copied < len)
1144                 zero_user_segment(page, from+copied, len);
1145 
1146         /* did file size increase? */
1147         /* (no need for i_size_read(); we caller holds i_mutex */
1148         if (pos+copied > inode->i_size)
1149                 check_cap = ceph_inode_set_size(inode, pos+copied);
1150 
1151         if (!PageUptodate(page))
1152                 SetPageUptodate(page);
1153 
1154         set_page_dirty(page);
1155 
1156         unlock_page(page);
1157         up_read(&mdsc->snap_rwsem);
1158         page_cache_release(page);
1159 
1160         if (check_cap)
1161                 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1162 
1163         return copied;
1164 }
1165 
1166 /*
1167  * we set .direct_IO to indicate direct io is supported, but since we
1168  * intercept O_DIRECT reads and writes early, this function should
1169  * never get called.
1170  */
1171 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1172                               const struct iovec *iov,
1173                               loff_t pos, unsigned long nr_segs)
1174 {
1175         WARN_ON(1);
1176         return -EINVAL;
1177 }
1178 
1179 const struct address_space_operations ceph_aops = {
1180         .readpage = ceph_readpage,
1181         .readpages = ceph_readpages,
1182         .writepage = ceph_writepage,
1183         .writepages = ceph_writepages_start,
1184         .write_begin = ceph_write_begin,
1185         .write_end = ceph_write_end,
1186         .set_page_dirty = ceph_set_page_dirty,
1187         .invalidatepage = ceph_invalidatepage,
1188         .releasepage = ceph_releasepage,
1189         .direct_IO = ceph_direct_io,
1190 };
1191 
1192 
1193 /*
1194  * vm ops
1195  */
1196 
1197 /*
1198  * Reuse write_begin here for simplicity.
1199  */
1200 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1201 {
1202         struct inode *inode = file_inode(vma->vm_file);
1203         struct page *page = vmf->page;
1204         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1205         loff_t off = page_offset(page);
1206         loff_t size, len;
1207         int ret;
1208 
1209         /* Update time before taking page lock */
1210         file_update_time(vma->vm_file);
1211 
1212         size = i_size_read(inode);
1213         if (off + PAGE_CACHE_SIZE <= size)
1214                 len = PAGE_CACHE_SIZE;
1215         else
1216                 len = size & ~PAGE_CACHE_MASK;
1217 
1218         dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1219              off, len, page, page->index);
1220 
1221         lock_page(page);
1222 
1223         ret = VM_FAULT_NOPAGE;
1224         if ((off > size) ||
1225             (page->mapping != inode->i_mapping))
1226                 goto out;
1227 
1228         ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1229         if (ret == 0) {
1230                 /* success.  we'll keep the page locked. */
1231                 set_page_dirty(page);
1232                 up_read(&mdsc->snap_rwsem);
1233                 ret = VM_FAULT_LOCKED;
1234         } else {
1235                 if (ret == -ENOMEM)
1236                         ret = VM_FAULT_OOM;
1237                 else
1238                         ret = VM_FAULT_SIGBUS;
1239         }
1240 out:
1241         dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1242         if (ret != VM_FAULT_LOCKED)
1243                 unlock_page(page);
1244         return ret;
1245 }
1246 
1247 static struct vm_operations_struct ceph_vmops = {
1248         .fault          = filemap_fault,
1249         .page_mkwrite   = ceph_page_mkwrite,
1250         .remap_pages    = generic_file_remap_pages,
1251 };
1252 
1253 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1254 {
1255         struct address_space *mapping = file->f_mapping;
1256 
1257         if (!mapping->a_ops->readpage)
1258                 return -ENOEXEC;
1259         file_accessed(file);
1260         vma->vm_ops = &ceph_vmops;
1261         return 0;
1262 }
1263 

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