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Sage Weil1d3576f2009-10-06 11:31:09 -07001#include "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 */
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09008#include <linux/slab.h>
Sage Weil1d3576f2009-10-06 11:31:09 -07009#include <linux/pagevec.h>
10#include <linux/task_io_accounting_ops.h>
11
12#include "super.h"
13#include "osd_client.h"
14
15/*
16 * Ceph address space ops.
17 *
18 * There are a few funny things going on here.
19 *
20 * The page->private field is used to reference a struct
21 * ceph_snap_context for _every_ dirty page. This indicates which
22 * snapshot the page was logically dirtied in, and thus which snap
23 * context needs to be associated with the osd write during writeback.
24 *
25 * Similarly, struct ceph_inode_info maintains a set of counters to
26 * count dirty pages on the inode. In the absense of snapshots,
27 * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
28 *
29 * When a snapshot is taken (that is, when the client receives
30 * notification that a snapshot was taken), each inode with caps and
31 * with dirty pages (dirty pages implies there is a cap) gets a new
32 * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
33 * order, new snaps go to the tail). The i_wrbuffer_ref_head count is
34 * moved to capsnap->dirty. (Unless a sync write is currently in
35 * progress. In that case, the capsnap is said to be "pending", new
36 * writes cannot start, and the capsnap isn't "finalized" until the
37 * write completes (or fails) and a final size/mtime for the inode for
38 * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0.
39 *
40 * On writeback, we must submit writes to the osd IN SNAP ORDER. So,
41 * we look for the first capsnap in i_cap_snaps and write out pages in
42 * that snap context _only_. Then we move on to the next capsnap,
43 * eventually reaching the "live" or "head" context (i.e., pages that
44 * are not yet snapped) and are writing the most recently dirtied
45 * pages.
46 *
47 * Invalidate and so forth must take care to ensure the dirty page
48 * accounting is preserved.
49 */
50
Yehuda Sadeh2baba252009-12-18 13:51:57 -080051#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
52#define CONGESTION_OFF_THRESH(congestion_kb) \
53 (CONGESTION_ON_THRESH(congestion_kb) - \
54 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
55
56
Sage Weil1d3576f2009-10-06 11:31:09 -070057
58/*
59 * Dirty a page. Optimistically adjust accounting, on the assumption
60 * that we won't race with invalidate. If we do, readjust.
61 */
62static int ceph_set_page_dirty(struct page *page)
63{
64 struct address_space *mapping = page->mapping;
65 struct inode *inode;
66 struct ceph_inode_info *ci;
67 int undo = 0;
68 struct ceph_snap_context *snapc;
69
70 if (unlikely(!mapping))
71 return !TestSetPageDirty(page);
72
73 if (TestSetPageDirty(page)) {
74 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
75 mapping->host, page, page->index);
76 return 0;
77 }
78
79 inode = mapping->host;
80 ci = ceph_inode(inode);
81
82 /*
83 * Note that we're grabbing a snapc ref here without holding
84 * any locks!
85 */
86 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
87
88 /* dirty the head */
89 spin_lock(&inode->i_lock);
90 if (ci->i_wrbuffer_ref_head == 0)
91 ci->i_head_snapc = ceph_get_snap_context(snapc);
92 ++ci->i_wrbuffer_ref_head;
93 if (ci->i_wrbuffer_ref == 0)
94 igrab(inode);
95 ++ci->i_wrbuffer_ref;
96 dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
97 "snapc %p seq %lld (%d snaps)\n",
98 mapping->host, page, page->index,
99 ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
100 ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
101 snapc, snapc->seq, snapc->num_snaps);
102 spin_unlock(&inode->i_lock);
103
104 /* now adjust page */
105 spin_lock_irq(&mapping->tree_lock);
106 if (page->mapping) { /* Race with truncate? */
107 WARN_ON_ONCE(!PageUptodate(page));
108
109 if (mapping_cap_account_dirty(mapping)) {
110 __inc_zone_page_state(page, NR_FILE_DIRTY);
111 __inc_bdi_stat(mapping->backing_dev_info,
112 BDI_RECLAIMABLE);
113 task_io_account_write(PAGE_CACHE_SIZE);
114 }
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 */
146static void ceph_invalidatepage(struct page *page, unsigned long offset)
147{
Alexander Beregalov4ce1e9a2010-02-22 17:17:44 +0300148 struct inode *inode;
Sage Weil1d3576f2009-10-06 11:31:09 -0700149 struct ceph_inode_info *ci;
150 struct ceph_snap_context *snapc = (void *)page->private;
151
152 BUG_ON(!PageLocked(page));
153 BUG_ON(!page->private);
154 BUG_ON(!PagePrivate(page));
155 BUG_ON(!page->mapping);
156
Alexander Beregalov4ce1e9a2010-02-22 17:17:44 +0300157 inode = page->mapping->host;
158
Sage Weil1d3576f2009-10-06 11:31:09 -0700159 /*
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)
168 ClearPageChecked(page);
169
170 ci = ceph_inode(inode);
171 if (offset == 0) {
172 dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
173 inode, page, page->index, offset);
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\n",
180 inode, page, page->index);
181 }
182}
183
184/* just a sanity check */
185static 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(page->private);
191 WARN_ON(PagePrivate(page));
192 return 0;
193}
194
195/*
196 * read a single page, without unlocking it.
197 */
198static int readpage_nounlock(struct file *filp, struct page *page)
199{
200 struct inode *inode = filp->f_dentry->d_inode;
201 struct ceph_inode_info *ci = ceph_inode(inode);
202 struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->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 page->index << PAGE_CACHE_SHIFT, &len,
210 ci->i_truncate_seq, ci->i_truncate_size,
211 &page, 1);
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
223out:
224 return err < 0 ? err : 0;
225}
226
227static 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 * Build a vector of contiguous pages from the provided page list.
236 */
237static struct page **page_vector_from_list(struct list_head *page_list,
238 unsigned *nr_pages)
239{
240 struct page **pages;
241 struct page *page;
242 int next_index, contig_pages = 0;
243
244 /* build page vector */
245 pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
246 if (!pages)
247 return ERR_PTR(-ENOMEM);
248
249 BUG_ON(list_empty(page_list));
250 next_index = list_entry(page_list->prev, struct page, lru)->index;
251 list_for_each_entry_reverse(page, page_list, lru) {
252 if (page->index == next_index) {
253 dout("readpages page %d %p\n", contig_pages, page);
254 pages[contig_pages] = page;
255 contig_pages++;
256 next_index++;
257 } else {
258 break;
259 }
260 }
261 *nr_pages = contig_pages;
262 return pages;
263}
264
265/*
266 * Read multiple pages. Leave pages we don't read + unlock in page_list;
267 * the caller (VM) cleans them up.
268 */
269static int ceph_readpages(struct file *file, struct address_space *mapping,
270 struct list_head *page_list, unsigned nr_pages)
271{
272 struct inode *inode = file->f_dentry->d_inode;
273 struct ceph_inode_info *ci = ceph_inode(inode);
274 struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
275 int rc = 0;
276 struct page **pages;
Sage Weil1d3576f2009-10-06 11:31:09 -0700277 loff_t offset;
278 u64 len;
279
280 dout("readpages %p file %p nr_pages %d\n",
281 inode, file, nr_pages);
282
283 pages = page_vector_from_list(page_list, &nr_pages);
284 if (IS_ERR(pages))
285 return PTR_ERR(pages);
286
287 /* guess read extent */
288 offset = pages[0]->index << PAGE_CACHE_SHIFT;
289 len = nr_pages << PAGE_CACHE_SHIFT;
290 rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
291 offset, &len,
292 ci->i_truncate_seq, ci->i_truncate_size,
293 pages, nr_pages);
294 if (rc == -ENOENT)
295 rc = 0;
296 if (rc < 0)
297 goto out;
298
Sage Weil1d3576f2009-10-06 11:31:09 -0700299 for (; !list_empty(page_list) && len > 0;
300 rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
301 struct page *page =
302 list_entry(page_list->prev, struct page, lru);
303
304 list_del(&page->lru);
305
306 if (rc < (int)PAGE_CACHE_SIZE) {
307 /* zero (remainder of) page */
308 int s = rc < 0 ? 0 : rc;
309 zero_user_segment(page, s, PAGE_CACHE_SIZE);
310 }
311
Yehuda Sadeh31459fe2010-03-17 13:54:02 -0700312 if (add_to_page_cache_lru(page, mapping, page->index, GFP_NOFS)) {
Sage Weil1d3576f2009-10-06 11:31:09 -0700313 page_cache_release(page);
314 dout("readpages %p add_to_page_cache failed %p\n",
315 inode, page);
316 continue;
317 }
318 dout("readpages %p adding %p idx %lu\n", inode, page,
319 page->index);
320 flush_dcache_page(page);
321 SetPageUptodate(page);
322 unlock_page(page);
Yehuda Sadeh31459fe2010-03-17 13:54:02 -0700323 page_cache_release(page);
Sage Weil1d3576f2009-10-06 11:31:09 -0700324 }
Sage Weil1d3576f2009-10-06 11:31:09 -0700325 rc = 0;
326
327out:
328 kfree(pages);
329 return rc;
330}
331
332/*
333 * Get ref for the oldest snapc for an inode with dirty data... that is, the
334 * only snap context we are allowed to write back.
Sage Weil1d3576f2009-10-06 11:31:09 -0700335 */
Sage Weil6298a332010-03-31 22:01:38 -0700336static struct ceph_snap_context *get_oldest_context(struct inode *inode,
337 u64 *snap_size)
Sage Weil1d3576f2009-10-06 11:31:09 -0700338{
339 struct ceph_inode_info *ci = ceph_inode(inode);
340 struct ceph_snap_context *snapc = NULL;
341 struct ceph_cap_snap *capsnap = NULL;
342
Sage Weil6298a332010-03-31 22:01:38 -0700343 spin_lock(&inode->i_lock);
Sage Weil1d3576f2009-10-06 11:31:09 -0700344 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
345 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
346 capsnap->context, capsnap->dirty_pages);
347 if (capsnap->dirty_pages) {
348 snapc = ceph_get_snap_context(capsnap->context);
349 if (snap_size)
350 *snap_size = capsnap->size;
351 break;
352 }
353 }
Sage Weil80e755f2010-03-31 21:52:10 -0700354 if (!snapc && ci->i_head_snapc) {
355 snapc = ceph_get_snap_context(ci->i_head_snapc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700356 dout(" head snapc %p has %d dirty pages\n",
357 snapc, ci->i_wrbuffer_ref_head);
358 }
Sage Weil1d3576f2009-10-06 11:31:09 -0700359 spin_unlock(&inode->i_lock);
360 return snapc;
361}
362
363/*
364 * Write a single page, but leave the page locked.
365 *
366 * If we get a write error, set the page error bit, but still adjust the
367 * dirty page accounting (i.e., page is no longer dirty).
368 */
369static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
370{
371 struct inode *inode;
372 struct ceph_inode_info *ci;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800373 struct ceph_client *client;
Sage Weil1d3576f2009-10-06 11:31:09 -0700374 struct ceph_osd_client *osdc;
375 loff_t page_off = page->index << PAGE_CACHE_SHIFT;
376 int len = PAGE_CACHE_SIZE;
377 loff_t i_size;
378 int err = 0;
Sage Weil6298a332010-03-31 22:01:38 -0700379 struct ceph_snap_context *snapc, *oldest;
Sage Weil1d3576f2009-10-06 11:31:09 -0700380 u64 snap_size = 0;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800381 long writeback_stat;
Sage Weil1d3576f2009-10-06 11:31:09 -0700382
383 dout("writepage %p idx %lu\n", page, page->index);
384
385 if (!page->mapping || !page->mapping->host) {
386 dout("writepage %p - no mapping\n", page);
387 return -EFAULT;
388 }
389 inode = page->mapping->host;
390 ci = ceph_inode(inode);
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800391 client = ceph_inode_to_client(inode);
392 osdc = &client->osdc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700393
394 /* verify this is a writeable snap context */
395 snapc = (void *)page->private;
396 if (snapc == NULL) {
397 dout("writepage %p page %p not dirty?\n", inode, page);
398 goto out;
399 }
Sage Weil6298a332010-03-31 22:01:38 -0700400 oldest = get_oldest_context(inode, &snap_size);
401 if (snapc->seq > oldest->seq) {
Sage Weil1d3576f2009-10-06 11:31:09 -0700402 dout("writepage %p page %p snapc %p not writeable - noop\n",
403 inode, page, (void *)page->private);
404 /* we should only noop if called by kswapd */
405 WARN_ON((current->flags & PF_MEMALLOC) == 0);
Sage Weil6298a332010-03-31 22:01:38 -0700406 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700407 goto out;
408 }
Sage Weil6298a332010-03-31 22:01:38 -0700409 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700410
411 /* is this a partial page at end of file? */
412 if (snap_size)
413 i_size = snap_size;
414 else
415 i_size = i_size_read(inode);
416 if (i_size < page_off + len)
417 len = i_size - page_off;
418
419 dout("writepage %p page %p index %lu on %llu~%u\n",
420 inode, page, page->index, page_off, len);
421
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800422 writeback_stat = atomic_long_inc_return(&client->writeback_count);
423 if (writeback_stat >
424 CONGESTION_ON_THRESH(client->mount_args->congestion_kb))
425 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
426
Sage Weil1d3576f2009-10-06 11:31:09 -0700427 set_page_writeback(page);
428 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
429 &ci->i_layout, snapc,
430 page_off, len,
431 ci->i_truncate_seq, ci->i_truncate_size,
432 &inode->i_mtime,
433 &page, 1, 0, 0, true);
434 if (err < 0) {
435 dout("writepage setting page/mapping error %d %p\n", err, page);
436 SetPageError(page);
437 mapping_set_error(&inode->i_data, err);
438 if (wbc)
439 wbc->pages_skipped++;
440 } else {
441 dout("writepage cleaned page %p\n", page);
442 err = 0; /* vfs expects us to return 0 */
443 }
444 page->private = 0;
445 ClearPagePrivate(page);
446 end_page_writeback(page);
447 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
Sage Weil6298a332010-03-31 22:01:38 -0700448 ceph_put_snap_context(snapc); /* page's reference */
Sage Weil1d3576f2009-10-06 11:31:09 -0700449out:
450 return err;
451}
452
453static int ceph_writepage(struct page *page, struct writeback_control *wbc)
454{
Yehuda Sadehdbd646a2009-12-16 14:51:06 -0800455 int err;
456 struct inode *inode = page->mapping->host;
457 BUG_ON(!inode);
458 igrab(inode);
459 err = writepage_nounlock(page, wbc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700460 unlock_page(page);
Yehuda Sadehdbd646a2009-12-16 14:51:06 -0800461 iput(inode);
Sage Weil1d3576f2009-10-06 11:31:09 -0700462 return err;
463}
464
465
466/*
467 * lame release_pages helper. release_pages() isn't exported to
468 * modules.
469 */
470static void ceph_release_pages(struct page **pages, int num)
471{
472 struct pagevec pvec;
473 int i;
474
475 pagevec_init(&pvec, 0);
476 for (i = 0; i < num; i++) {
477 if (pagevec_add(&pvec, pages[i]) == 0)
478 pagevec_release(&pvec);
479 }
480 pagevec_release(&pvec);
481}
482
483
484/*
485 * async writeback completion handler.
486 *
487 * If we get an error, set the mapping error bit, but not the individual
488 * page error bits.
489 */
490static void writepages_finish(struct ceph_osd_request *req,
491 struct ceph_msg *msg)
492{
493 struct inode *inode = req->r_inode;
494 struct ceph_osd_reply_head *replyhead;
495 struct ceph_osd_op *op;
496 struct ceph_inode_info *ci = ceph_inode(inode);
497 unsigned wrote;
Sage Weil1d3576f2009-10-06 11:31:09 -0700498 struct page *page;
499 int i;
500 struct ceph_snap_context *snapc = req->r_snapc;
501 struct address_space *mapping = inode->i_mapping;
Sage Weil1d3576f2009-10-06 11:31:09 -0700502 __s32 rc = -EIO;
503 u64 bytes = 0;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800504 struct ceph_client *client = ceph_inode_to_client(inode);
505 long writeback_stat;
Sage Weil7ff899d2010-04-23 10:25:33 -0700506 unsigned issued = ceph_caps_issued(ci);
Sage Weil1d3576f2009-10-06 11:31:09 -0700507
508 /* parse reply */
509 replyhead = msg->front.iov_base;
510 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
511 op = (void *)(replyhead + 1);
512 rc = le32_to_cpu(replyhead->result);
513 bytes = le64_to_cpu(op->extent.length);
514
515 if (rc >= 0) {
Sage Weil79788c62010-02-02 16:34:04 -0800516 /*
517 * Assume we wrote the pages we originally sent. The
518 * osd might reply with fewer pages if our writeback
519 * raced with a truncation and was adjusted at the osd,
520 * so don't believe the reply.
521 */
522 wrote = req->r_num_pages;
Sage Weil1d3576f2009-10-06 11:31:09 -0700523 } else {
524 wrote = 0;
525 mapping_set_error(mapping, rc);
526 }
527 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
528 inode, rc, bytes, wrote);
529
530 /* clean all pages */
531 for (i = 0; i < req->r_num_pages; i++) {
532 page = req->r_pages[i];
533 BUG_ON(!page);
534 WARN_ON(!PageUptodate(page));
535
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800536 writeback_stat =
537 atomic_long_dec_return(&client->writeback_count);
538 if (writeback_stat <
539 CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))
540 clear_bdi_congested(&client->backing_dev_info,
541 BLK_RW_ASYNC);
542
Sage Weil80e755f2010-03-31 21:52:10 -0700543 ceph_put_snap_context((void *)page->private);
Sage Weil1d3576f2009-10-06 11:31:09 -0700544 page->private = 0;
545 ClearPagePrivate(page);
Sage Weil1d3576f2009-10-06 11:31:09 -0700546 dout("unlocking %d %p\n", i, page);
547 end_page_writeback(page);
Yehuda Sadehe63dc5c2010-02-19 00:07:01 +0000548
549 /*
550 * We lost the cache cap, need to truncate the page before
551 * it is unlocked, otherwise we'd truncate it later in the
552 * page truncation thread, possibly losing some data that
553 * raced its way in
554 */
555 if ((issued & CEPH_CAP_FILE_CACHE) == 0)
556 generic_error_remove_page(inode->i_mapping, page);
557
Sage Weil1d3576f2009-10-06 11:31:09 -0700558 unlock_page(page);
559 }
560 dout("%p wrote+cleaned %d pages\n", inode, wrote);
561 ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
562
563 ceph_release_pages(req->r_pages, req->r_num_pages);
564 if (req->r_pages_from_pool)
565 mempool_free(req->r_pages,
Cheng Renquan640ef792010-03-26 17:40:33 +0800566 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
Sage Weil1d3576f2009-10-06 11:31:09 -0700567 else
568 kfree(req->r_pages);
569 ceph_osdc_put_request(req);
570}
571
572/*
573 * allocate a page vec, either directly, or if necessary, via a the
574 * mempool. we avoid the mempool if we can because req->r_num_pages
575 * may be less than the maximum write size.
576 */
577static void alloc_page_vec(struct ceph_client *client,
578 struct ceph_osd_request *req)
579{
580 req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
581 GFP_NOFS);
582 if (!req->r_pages) {
583 req->r_pages = mempool_alloc(client->wb_pagevec_pool, GFP_NOFS);
584 req->r_pages_from_pool = 1;
585 WARN_ON(!req->r_pages);
586 }
587}
588
589/*
590 * initiate async writeback
591 */
592static int ceph_writepages_start(struct address_space *mapping,
593 struct writeback_control *wbc)
594{
595 struct inode *inode = mapping->host;
596 struct backing_dev_info *bdi = mapping->backing_dev_info;
597 struct ceph_inode_info *ci = ceph_inode(inode);
Julia Lawallec7384e2010-01-20 15:16:41 -0800598 struct ceph_client *client;
Sage Weil1d3576f2009-10-06 11:31:09 -0700599 pgoff_t index, start, end;
600 int range_whole = 0;
601 int should_loop = 1;
602 pgoff_t max_pages = 0, max_pages_ever = 0;
Sage Weil80e755f2010-03-31 21:52:10 -0700603 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700604 struct pagevec pvec;
605 int done = 0;
606 int rc = 0;
607 unsigned wsize = 1 << inode->i_blkbits;
608 struct ceph_osd_request *req = NULL;
609 int do_sync;
610 u64 snap_size = 0;
611
612 /*
613 * Include a 'sync' in the OSD request if this is a data
614 * integrity write (e.g., O_SYNC write or fsync()), or if our
615 * cap is being revoked.
616 */
617 do_sync = wbc->sync_mode == WB_SYNC_ALL;
618 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
619 do_sync = 1;
620 dout("writepages_start %p dosync=%d (mode=%s)\n",
621 inode, do_sync,
622 wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
623 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
624
625 client = ceph_inode_to_client(inode);
626 if (client->mount_state == CEPH_MOUNT_SHUTDOWN) {
627 pr_warning("writepage_start %p on forced umount\n", inode);
628 return -EIO; /* we're in a forced umount, don't write! */
629 }
Sage Weil6b805182009-10-27 11:50:50 -0700630 if (client->mount_args->wsize && client->mount_args->wsize < wsize)
631 wsize = client->mount_args->wsize;
Sage Weil1d3576f2009-10-06 11:31:09 -0700632 if (wsize < PAGE_CACHE_SIZE)
633 wsize = PAGE_CACHE_SIZE;
634 max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
635
636 pagevec_init(&pvec, 0);
637
638 /* ?? */
639 if (wbc->nonblocking && bdi_write_congested(bdi)) {
640 dout(" writepages congested\n");
641 wbc->encountered_congestion = 1;
642 goto out_final;
643 }
644
645 /* where to start/end? */
646 if (wbc->range_cyclic) {
647 start = mapping->writeback_index; /* Start from prev offset */
648 end = -1;
649 dout(" cyclic, start at %lu\n", start);
650 } else {
651 start = wbc->range_start >> PAGE_CACHE_SHIFT;
652 end = wbc->range_end >> PAGE_CACHE_SHIFT;
653 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
654 range_whole = 1;
655 should_loop = 0;
656 dout(" not cyclic, %lu to %lu\n", start, end);
657 }
658 index = start;
659
660retry:
661 /* find oldest snap context with dirty data */
662 ceph_put_snap_context(snapc);
663 snapc = get_oldest_context(inode, &snap_size);
664 if (!snapc) {
665 /* hmm, why does writepages get called when there
666 is no dirty data? */
667 dout(" no snap context with dirty data?\n");
668 goto out;
669 }
670 dout(" oldest snapc is %p seq %lld (%d snaps)\n",
671 snapc, snapc->seq, snapc->num_snaps);
672 if (last_snapc && snapc != last_snapc) {
673 /* if we switched to a newer snapc, restart our scan at the
674 * start of the original file range. */
675 dout(" snapc differs from last pass, restarting at %lu\n",
676 index);
677 index = start;
678 }
679 last_snapc = snapc;
680
681 while (!done && index <= end) {
682 unsigned i;
683 int first;
684 pgoff_t next;
685 int pvec_pages, locked_pages;
686 struct page *page;
687 int want;
688 u64 offset, len;
689 struct ceph_osd_request_head *reqhead;
690 struct ceph_osd_op *op;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800691 long writeback_stat;
Sage Weil1d3576f2009-10-06 11:31:09 -0700692
693 next = 0;
694 locked_pages = 0;
695 max_pages = max_pages_ever;
696
697get_more_pages:
698 first = -1;
699 want = min(end - index,
700 min((pgoff_t)PAGEVEC_SIZE,
701 max_pages - (pgoff_t)locked_pages) - 1)
702 + 1;
703 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
704 PAGECACHE_TAG_DIRTY,
705 want);
706 dout("pagevec_lookup_tag got %d\n", pvec_pages);
707 if (!pvec_pages && !locked_pages)
708 break;
709 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
710 page = pvec.pages[i];
711 dout("? %p idx %lu\n", page, page->index);
712 if (locked_pages == 0)
713 lock_page(page); /* first page */
714 else if (!trylock_page(page))
715 break;
716
717 /* only dirty pages, or our accounting breaks */
718 if (unlikely(!PageDirty(page)) ||
719 unlikely(page->mapping != mapping)) {
720 dout("!dirty or !mapping %p\n", page);
721 unlock_page(page);
722 break;
723 }
724 if (!wbc->range_cyclic && page->index > end) {
725 dout("end of range %p\n", page);
726 done = 1;
727 unlock_page(page);
728 break;
729 }
730 if (next && (page->index != next)) {
731 dout("not consecutive %p\n", page);
732 unlock_page(page);
733 break;
734 }
735 if (wbc->sync_mode != WB_SYNC_NONE) {
736 dout("waiting on writeback %p\n", page);
737 wait_on_page_writeback(page);
738 }
739 if ((snap_size && page_offset(page) > snap_size) ||
740 (!snap_size &&
741 page_offset(page) > i_size_read(inode))) {
742 dout("%p page eof %llu\n", page, snap_size ?
743 snap_size : i_size_read(inode));
744 done = 1;
745 unlock_page(page);
746 break;
747 }
748 if (PageWriteback(page)) {
749 dout("%p under writeback\n", page);
750 unlock_page(page);
751 break;
752 }
753
754 /* only if matching snap context */
Sage Weil80e755f2010-03-31 21:52:10 -0700755 pgsnapc = (void *)page->private;
756 if (pgsnapc->seq > snapc->seq) {
757 dout("page snapc %p %lld > oldest %p %lld\n",
758 pgsnapc, pgsnapc->seq, snapc, snapc->seq);
Sage Weil1d3576f2009-10-06 11:31:09 -0700759 unlock_page(page);
760 if (!locked_pages)
761 continue; /* keep looking for snap */
762 break;
763 }
764
765 if (!clear_page_dirty_for_io(page)) {
766 dout("%p !clear_page_dirty_for_io\n", page);
767 unlock_page(page);
768 break;
769 }
770
771 /* ok */
772 if (locked_pages == 0) {
773 /* prepare async write request */
774 offset = page->index << PAGE_CACHE_SHIFT;
775 len = wsize;
776 req = ceph_osdc_new_request(&client->osdc,
777 &ci->i_layout,
778 ceph_vino(inode),
779 offset, &len,
780 CEPH_OSD_OP_WRITE,
781 CEPH_OSD_FLAG_WRITE |
782 CEPH_OSD_FLAG_ONDISK,
783 snapc, do_sync,
784 ci->i_truncate_seq,
785 ci->i_truncate_size,
786 &inode->i_mtime, true, 1);
787 max_pages = req->r_num_pages;
788
789 alloc_page_vec(client, req);
790 req->r_callback = writepages_finish;
791 req->r_inode = inode;
Sage Weil1d3576f2009-10-06 11:31:09 -0700792 }
793
794 /* note position of first page in pvec */
795 if (first < 0)
796 first = i;
797 dout("%p will write page %p idx %lu\n",
798 inode, page, page->index);
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800799
800 writeback_stat = atomic_long_inc_return(&client->writeback_count);
801 if (writeback_stat > CONGESTION_ON_THRESH(client->mount_args->congestion_kb)) {
802 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
803 }
804
Sage Weil1d3576f2009-10-06 11:31:09 -0700805 set_page_writeback(page);
806 req->r_pages[locked_pages] = page;
807 locked_pages++;
808 next = page->index + 1;
809 }
810
811 /* did we get anything? */
812 if (!locked_pages)
813 goto release_pvec_pages;
814 if (i) {
815 int j;
816 BUG_ON(!locked_pages || first < 0);
817
818 if (pvec_pages && i == pvec_pages &&
819 locked_pages < max_pages) {
820 dout("reached end pvec, trying for more\n");
821 pagevec_reinit(&pvec);
822 goto get_more_pages;
823 }
824
825 /* shift unused pages over in the pvec... we
826 * will need to release them below. */
827 for (j = i; j < pvec_pages; j++) {
828 dout(" pvec leftover page %p\n",
829 pvec.pages[j]);
830 pvec.pages[j-i+first] = pvec.pages[j];
831 }
832 pvec.nr -= i-first;
833 }
834
835 /* submit the write */
836 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
837 len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
838 (u64)locked_pages << PAGE_CACHE_SHIFT);
839 dout("writepages got %d pages at %llu~%llu\n",
840 locked_pages, offset, len);
841
842 /* revise final length, page count */
843 req->r_num_pages = locked_pages;
844 reqhead = req->r_request->front.iov_base;
845 op = (void *)(reqhead + 1);
846 op->extent.length = cpu_to_le64(len);
847 op->payload_len = cpu_to_le32(len);
848 req->r_request->hdr.data_len = cpu_to_le32(len);
849
850 ceph_osdc_start_request(&client->osdc, req, true);
851 req = NULL;
852
853 /* continue? */
854 index = next;
855 wbc->nr_to_write -= locked_pages;
856 if (wbc->nr_to_write <= 0)
857 done = 1;
858
859release_pvec_pages:
860 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
861 pvec.nr ? pvec.pages[0] : NULL);
862 pagevec_release(&pvec);
863
864 if (locked_pages && !done)
865 goto retry;
866 }
867
868 if (should_loop && !done) {
869 /* more to do; loop back to beginning of file */
870 dout("writepages looping back to beginning of file\n");
871 should_loop = 0;
872 index = 0;
873 goto retry;
874 }
875
876 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
877 mapping->writeback_index = index;
878
879out:
880 if (req)
881 ceph_osdc_put_request(req);
882 if (rc > 0)
883 rc = 0; /* vfs expects us to return 0 */
884 ceph_put_snap_context(snapc);
885 dout("writepages done, rc = %d\n", rc);
886out_final:
887 return rc;
888}
889
890
891
892/*
893 * See if a given @snapc is either writeable, or already written.
894 */
895static int context_is_writeable_or_written(struct inode *inode,
896 struct ceph_snap_context *snapc)
897{
898 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
Sage Weil6298a332010-03-31 22:01:38 -0700899 int ret = !oldest || snapc->seq <= oldest->seq;
900
901 ceph_put_snap_context(oldest);
902 return ret;
Sage Weil1d3576f2009-10-06 11:31:09 -0700903}
904
905/*
906 * We are only allowed to write into/dirty the page if the page is
907 * clean, or already dirty within the same snap context.
Sage Weil8f883c22010-03-19 13:27:53 -0700908 *
909 * called with page locked.
910 * return success with page locked,
911 * or any failure (incl -EAGAIN) with page unlocked.
Sage Weil1d3576f2009-10-06 11:31:09 -0700912 */
Yehuda Sadeh4af6b222010-02-09 11:02:51 -0800913static int ceph_update_writeable_page(struct file *file,
914 loff_t pos, unsigned len,
915 struct page *page)
Sage Weil1d3576f2009-10-06 11:31:09 -0700916{
917 struct inode *inode = file->f_dentry->d_inode;
918 struct ceph_inode_info *ci = ceph_inode(inode);
919 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700920 loff_t page_off = pos & PAGE_CACHE_MASK;
921 int pos_in_page = pos & ~PAGE_CACHE_MASK;
922 int end_in_page = pos_in_page + len;
923 loff_t i_size;
Sage Weil1d3576f2009-10-06 11:31:09 -0700924 int r;
Sage Weil80e755f2010-03-31 21:52:10 -0700925 struct ceph_snap_context *snapc, *oldest;
Sage Weil1d3576f2009-10-06 11:31:09 -0700926
Sage Weil1d3576f2009-10-06 11:31:09 -0700927retry_locked:
928 /* writepages currently holds page lock, but if we change that later, */
929 wait_on_page_writeback(page);
930
931 /* check snap context */
932 BUG_ON(!ci->i_snap_realm);
933 down_read(&mdsc->snap_rwsem);
934 BUG_ON(!ci->i_snap_realm->cached_context);
Sage Weil80e755f2010-03-31 21:52:10 -0700935 snapc = (void *)page->private;
936 if (snapc && snapc != ci->i_head_snapc) {
Sage Weil1d3576f2009-10-06 11:31:09 -0700937 /*
938 * this page is already dirty in another (older) snap
939 * context! is it writeable now?
940 */
Sage Weil80e755f2010-03-31 21:52:10 -0700941 oldest = get_oldest_context(inode, NULL);
Sage Weil1d3576f2009-10-06 11:31:09 -0700942 up_read(&mdsc->snap_rwsem);
943
Sage Weil80e755f2010-03-31 21:52:10 -0700944 if (snapc->seq > oldest->seq) {
Sage Weil6298a332010-03-31 22:01:38 -0700945 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700946 dout(" page %p snapc %p not current or oldest\n",
Sage Weil6298a332010-03-31 22:01:38 -0700947 page, snapc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700948 /*
949 * queue for writeback, and wait for snapc to
950 * be writeable or written
951 */
Sage Weil6298a332010-03-31 22:01:38 -0700952 snapc = ceph_get_snap_context(snapc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700953 unlock_page(page);
Sage Weil3c6f6b72010-02-09 15:24:44 -0800954 ceph_queue_writeback(inode);
Sage Weil8f883c22010-03-19 13:27:53 -0700955 r = wait_event_interruptible(ci->i_cap_wq,
Sage Weil1d3576f2009-10-06 11:31:09 -0700956 context_is_writeable_or_written(inode, snapc));
957 ceph_put_snap_context(snapc);
Sage Weil8f883c22010-03-19 13:27:53 -0700958 if (r == -ERESTARTSYS)
959 return r;
Yehuda Sadeh4af6b222010-02-09 11:02:51 -0800960 return -EAGAIN;
Sage Weil1d3576f2009-10-06 11:31:09 -0700961 }
Sage Weil6298a332010-03-31 22:01:38 -0700962 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700963
964 /* yay, writeable, do it now (without dropping page lock) */
965 dout(" page %p snapc %p not current, but oldest\n",
966 page, snapc);
967 if (!clear_page_dirty_for_io(page))
968 goto retry_locked;
969 r = writepage_nounlock(page, NULL);
970 if (r < 0)
971 goto fail_nosnap;
972 goto retry_locked;
973 }
974
975 if (PageUptodate(page)) {
976 dout(" page %p already uptodate\n", page);
977 return 0;
978 }
979
980 /* full page? */
981 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
982 return 0;
983
984 /* past end of file? */
985 i_size = inode->i_size; /* caller holds i_mutex */
986
987 if (i_size + len > inode->i_sb->s_maxbytes) {
988 /* file is too big */
989 r = -EINVAL;
990 goto fail;
991 }
992
993 if (page_off >= i_size ||
994 (pos_in_page == 0 && (pos+len) >= i_size &&
995 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
996 dout(" zeroing %p 0 - %d and %d - %d\n",
997 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
998 zero_user_segments(page,
999 0, pos_in_page,
1000 end_in_page, PAGE_CACHE_SIZE);
1001 return 0;
1002 }
1003
1004 /* we need to read it. */
1005 up_read(&mdsc->snap_rwsem);
1006 r = readpage_nounlock(file, page);
1007 if (r < 0)
1008 goto fail_nosnap;
1009 goto retry_locked;
1010
1011fail:
1012 up_read(&mdsc->snap_rwsem);
1013fail_nosnap:
1014 unlock_page(page);
1015 return r;
1016}
1017
1018/*
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001019 * We are only allowed to write into/dirty the page if the page is
1020 * clean, or already dirty within the same snap context.
1021 */
1022static int ceph_write_begin(struct file *file, struct address_space *mapping,
1023 loff_t pos, unsigned len, unsigned flags,
1024 struct page **pagep, void **fsdata)
1025{
1026 struct inode *inode = file->f_dentry->d_inode;
1027 struct page *page;
1028 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1029 int r;
1030
1031 do {
Sage Weil8f883c22010-03-19 13:27:53 -07001032 /* get a page */
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001033 page = grab_cache_page_write_begin(mapping, index, 0);
1034 if (!page)
1035 return -ENOMEM;
1036 *pagep = page;
1037
1038 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1039 inode, page, (int)pos, (int)len);
1040
1041 r = ceph_update_writeable_page(file, pos, len, page);
1042 } while (r == -EAGAIN);
1043
1044 return r;
1045}
1046
1047/*
Sage Weil1d3576f2009-10-06 11:31:09 -07001048 * we don't do anything in here that simple_write_end doesn't do
1049 * except adjust dirty page accounting and drop read lock on
1050 * mdsc->snap_rwsem.
1051 */
1052static int ceph_write_end(struct file *file, struct address_space *mapping,
1053 loff_t pos, unsigned len, unsigned copied,
1054 struct page *page, void *fsdata)
1055{
1056 struct inode *inode = file->f_dentry->d_inode;
Yehuda Sadeh2baba252009-12-18 13:51:57 -08001057 struct ceph_client *client = ceph_inode_to_client(inode);
1058 struct ceph_mds_client *mdsc = &client->mdsc;
Sage Weil1d3576f2009-10-06 11:31:09 -07001059 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1060 int check_cap = 0;
1061
1062 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1063 inode, page, (int)pos, (int)copied, (int)len);
1064
1065 /* zero the stale part of the page if we did a short copy */
1066 if (copied < len)
1067 zero_user_segment(page, from+copied, len);
1068
1069 /* did file size increase? */
1070 /* (no need for i_size_read(); we caller holds i_mutex */
1071 if (pos+copied > inode->i_size)
1072 check_cap = ceph_inode_set_size(inode, pos+copied);
1073
1074 if (!PageUptodate(page))
1075 SetPageUptodate(page);
1076
1077 set_page_dirty(page);
1078
1079 unlock_page(page);
1080 up_read(&mdsc->snap_rwsem);
1081 page_cache_release(page);
1082
1083 if (check_cap)
1084 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1085
1086 return copied;
1087}
1088
1089/*
1090 * we set .direct_IO to indicate direct io is supported, but since we
1091 * intercept O_DIRECT reads and writes early, this function should
1092 * never get called.
1093 */
1094static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1095 const struct iovec *iov,
1096 loff_t pos, unsigned long nr_segs)
1097{
1098 WARN_ON(1);
1099 return -EINVAL;
1100}
1101
1102const struct address_space_operations ceph_aops = {
1103 .readpage = ceph_readpage,
1104 .readpages = ceph_readpages,
1105 .writepage = ceph_writepage,
1106 .writepages = ceph_writepages_start,
1107 .write_begin = ceph_write_begin,
1108 .write_end = ceph_write_end,
1109 .set_page_dirty = ceph_set_page_dirty,
1110 .invalidatepage = ceph_invalidatepage,
1111 .releasepage = ceph_releasepage,
1112 .direct_IO = ceph_direct_io,
1113};
1114
1115
1116/*
1117 * vm ops
1118 */
1119
1120/*
1121 * Reuse write_begin here for simplicity.
1122 */
1123static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1124{
1125 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1126 struct page *page = vmf->page;
1127 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
1128 loff_t off = page->index << PAGE_CACHE_SHIFT;
1129 loff_t size, len;
Sage Weil1d3576f2009-10-06 11:31:09 -07001130 int ret;
1131
1132 size = i_size_read(inode);
1133 if (off + PAGE_CACHE_SIZE <= size)
1134 len = PAGE_CACHE_SIZE;
1135 else
1136 len = size & ~PAGE_CACHE_MASK;
1137
1138 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1139 off, len, page, page->index);
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001140
1141 lock_page(page);
1142
1143 ret = VM_FAULT_NOPAGE;
1144 if ((off > size) ||
1145 (page->mapping != inode->i_mapping))
1146 goto out;
1147
1148 ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1149 if (ret == 0) {
1150 /* success. we'll keep the page locked. */
Sage Weil1d3576f2009-10-06 11:31:09 -07001151 set_page_dirty(page);
1152 up_read(&mdsc->snap_rwsem);
Sage Weil1d3576f2009-10-06 11:31:09 -07001153 ret = VM_FAULT_LOCKED;
1154 } else {
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001155 if (ret == -ENOMEM)
1156 ret = VM_FAULT_OOM;
1157 else
1158 ret = VM_FAULT_SIGBUS;
Sage Weil1d3576f2009-10-06 11:31:09 -07001159 }
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001160out:
Sage Weil1d3576f2009-10-06 11:31:09 -07001161 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001162 if (ret != VM_FAULT_LOCKED)
1163 unlock_page(page);
Sage Weil1d3576f2009-10-06 11:31:09 -07001164 return ret;
1165}
1166
1167static struct vm_operations_struct ceph_vmops = {
1168 .fault = filemap_fault,
1169 .page_mkwrite = ceph_page_mkwrite,
1170};
1171
1172int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1173{
1174 struct address_space *mapping = file->f_mapping;
1175
1176 if (!mapping->a_ops->readpage)
1177 return -ENOEXEC;
1178 file_accessed(file);
1179 vma->vm_ops = &ceph_vmops;
1180 vma->vm_flags |= VM_CAN_NONLINEAR;
1181 return 0;
1182}