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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
Sage Weil213c99e2010-08-03 10:25:11 -0700312 if (add_to_page_cache_lru(page, mapping, page->index,
313 GFP_NOFS)) {
Sage Weil1d3576f2009-10-06 11:31:09 -0700314 page_cache_release(page);
315 dout("readpages %p add_to_page_cache failed %p\n",
316 inode, page);
317 continue;
318 }
319 dout("readpages %p adding %p idx %lu\n", inode, page,
320 page->index);
321 flush_dcache_page(page);
322 SetPageUptodate(page);
323 unlock_page(page);
Yehuda Sadeh31459fe2010-03-17 13:54:02 -0700324 page_cache_release(page);
Sage Weil1d3576f2009-10-06 11:31:09 -0700325 }
Sage Weil1d3576f2009-10-06 11:31:09 -0700326 rc = 0;
327
328out:
329 kfree(pages);
330 return rc;
331}
332
333/*
334 * Get ref for the oldest snapc for an inode with dirty data... that is, the
335 * only snap context we are allowed to write back.
Sage Weil1d3576f2009-10-06 11:31:09 -0700336 */
Sage Weil6298a332010-03-31 22:01:38 -0700337static struct ceph_snap_context *get_oldest_context(struct inode *inode,
338 u64 *snap_size)
Sage Weil1d3576f2009-10-06 11:31:09 -0700339{
340 struct ceph_inode_info *ci = ceph_inode(inode);
341 struct ceph_snap_context *snapc = NULL;
342 struct ceph_cap_snap *capsnap = NULL;
343
Sage Weil6298a332010-03-31 22:01:38 -0700344 spin_lock(&inode->i_lock);
Sage Weil1d3576f2009-10-06 11:31:09 -0700345 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
346 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
347 capsnap->context, capsnap->dirty_pages);
348 if (capsnap->dirty_pages) {
349 snapc = ceph_get_snap_context(capsnap->context);
350 if (snap_size)
351 *snap_size = capsnap->size;
352 break;
353 }
354 }
Sage Weil80e755f2010-03-31 21:52:10 -0700355 if (!snapc && ci->i_head_snapc) {
356 snapc = ceph_get_snap_context(ci->i_head_snapc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700357 dout(" head snapc %p has %d dirty pages\n",
358 snapc, ci->i_wrbuffer_ref_head);
359 }
Sage Weil1d3576f2009-10-06 11:31:09 -0700360 spin_unlock(&inode->i_lock);
361 return snapc;
362}
363
364/*
365 * Write a single page, but leave the page locked.
366 *
367 * If we get a write error, set the page error bit, but still adjust the
368 * dirty page accounting (i.e., page is no longer dirty).
369 */
370static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
371{
372 struct inode *inode;
373 struct ceph_inode_info *ci;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800374 struct ceph_client *client;
Sage Weil1d3576f2009-10-06 11:31:09 -0700375 struct ceph_osd_client *osdc;
376 loff_t page_off = page->index << PAGE_CACHE_SHIFT;
377 int len = PAGE_CACHE_SIZE;
378 loff_t i_size;
379 int err = 0;
Sage Weil6298a332010-03-31 22:01:38 -0700380 struct ceph_snap_context *snapc, *oldest;
Sage Weil1d3576f2009-10-06 11:31:09 -0700381 u64 snap_size = 0;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800382 long writeback_stat;
Sage Weil1d3576f2009-10-06 11:31:09 -0700383
384 dout("writepage %p idx %lu\n", page, page->index);
385
386 if (!page->mapping || !page->mapping->host) {
387 dout("writepage %p - no mapping\n", page);
388 return -EFAULT;
389 }
390 inode = page->mapping->host;
391 ci = ceph_inode(inode);
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800392 client = ceph_inode_to_client(inode);
393 osdc = &client->osdc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700394
395 /* verify this is a writeable snap context */
396 snapc = (void *)page->private;
397 if (snapc == NULL) {
398 dout("writepage %p page %p not dirty?\n", inode, page);
399 goto out;
400 }
Sage Weil6298a332010-03-31 22:01:38 -0700401 oldest = get_oldest_context(inode, &snap_size);
402 if (snapc->seq > oldest->seq) {
Sage Weil1d3576f2009-10-06 11:31:09 -0700403 dout("writepage %p page %p snapc %p not writeable - noop\n",
404 inode, page, (void *)page->private);
405 /* we should only noop if called by kswapd */
406 WARN_ON((current->flags & PF_MEMALLOC) == 0);
Sage Weil6298a332010-03-31 22:01:38 -0700407 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700408 goto out;
409 }
Sage Weil6298a332010-03-31 22:01:38 -0700410 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700411
412 /* is this a partial page at end of file? */
413 if (snap_size)
414 i_size = snap_size;
415 else
416 i_size = i_size_read(inode);
417 if (i_size < page_off + len)
418 len = i_size - page_off;
419
420 dout("writepage %p page %p index %lu on %llu~%u\n",
421 inode, page, page->index, page_off, len);
422
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800423 writeback_stat = atomic_long_inc_return(&client->writeback_count);
424 if (writeback_stat >
425 CONGESTION_ON_THRESH(client->mount_args->congestion_kb))
426 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
427
Sage Weil1d3576f2009-10-06 11:31:09 -0700428 set_page_writeback(page);
429 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
430 &ci->i_layout, snapc,
431 page_off, len,
432 ci->i_truncate_seq, ci->i_truncate_size,
433 &inode->i_mtime,
434 &page, 1, 0, 0, true);
435 if (err < 0) {
436 dout("writepage setting page/mapping error %d %p\n", err, page);
437 SetPageError(page);
438 mapping_set_error(&inode->i_data, err);
439 if (wbc)
440 wbc->pages_skipped++;
441 } else {
442 dout("writepage cleaned page %p\n", page);
443 err = 0; /* vfs expects us to return 0 */
444 }
445 page->private = 0;
446 ClearPagePrivate(page);
447 end_page_writeback(page);
448 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
Sage Weil6298a332010-03-31 22:01:38 -0700449 ceph_put_snap_context(snapc); /* page's reference */
Sage Weil1d3576f2009-10-06 11:31:09 -0700450out:
451 return err;
452}
453
454static int ceph_writepage(struct page *page, struct writeback_control *wbc)
455{
Yehuda Sadehdbd646a2009-12-16 14:51:06 -0800456 int err;
457 struct inode *inode = page->mapping->host;
458 BUG_ON(!inode);
459 igrab(inode);
460 err = writepage_nounlock(page, wbc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700461 unlock_page(page);
Yehuda Sadehdbd646a2009-12-16 14:51:06 -0800462 iput(inode);
Sage Weil1d3576f2009-10-06 11:31:09 -0700463 return err;
464}
465
466
467/*
468 * lame release_pages helper. release_pages() isn't exported to
469 * modules.
470 */
471static void ceph_release_pages(struct page **pages, int num)
472{
473 struct pagevec pvec;
474 int i;
475
476 pagevec_init(&pvec, 0);
477 for (i = 0; i < num; i++) {
478 if (pagevec_add(&pvec, pages[i]) == 0)
479 pagevec_release(&pvec);
480 }
481 pagevec_release(&pvec);
482}
483
484
485/*
486 * async writeback completion handler.
487 *
488 * If we get an error, set the mapping error bit, but not the individual
489 * page error bits.
490 */
491static void writepages_finish(struct ceph_osd_request *req,
492 struct ceph_msg *msg)
493{
494 struct inode *inode = req->r_inode;
495 struct ceph_osd_reply_head *replyhead;
496 struct ceph_osd_op *op;
497 struct ceph_inode_info *ci = ceph_inode(inode);
498 unsigned wrote;
Sage Weil1d3576f2009-10-06 11:31:09 -0700499 struct page *page;
500 int i;
501 struct ceph_snap_context *snapc = req->r_snapc;
502 struct address_space *mapping = inode->i_mapping;
Sage Weil1d3576f2009-10-06 11:31:09 -0700503 __s32 rc = -EIO;
504 u64 bytes = 0;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800505 struct ceph_client *client = ceph_inode_to_client(inode);
506 long writeback_stat;
Sage Weil7ff899d2010-04-23 10:25:33 -0700507 unsigned issued = ceph_caps_issued(ci);
Sage Weil1d3576f2009-10-06 11:31:09 -0700508
509 /* parse reply */
510 replyhead = msg->front.iov_base;
511 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
512 op = (void *)(replyhead + 1);
513 rc = le32_to_cpu(replyhead->result);
514 bytes = le64_to_cpu(op->extent.length);
515
516 if (rc >= 0) {
Sage Weil79788c62010-02-02 16:34:04 -0800517 /*
518 * Assume we wrote the pages we originally sent. The
519 * osd might reply with fewer pages if our writeback
520 * raced with a truncation and was adjusted at the osd,
521 * so don't believe the reply.
522 */
523 wrote = req->r_num_pages;
Sage Weil1d3576f2009-10-06 11:31:09 -0700524 } else {
525 wrote = 0;
526 mapping_set_error(mapping, rc);
527 }
528 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
529 inode, rc, bytes, wrote);
530
531 /* clean all pages */
532 for (i = 0; i < req->r_num_pages; i++) {
533 page = req->r_pages[i];
534 BUG_ON(!page);
535 WARN_ON(!PageUptodate(page));
536
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800537 writeback_stat =
538 atomic_long_dec_return(&client->writeback_count);
539 if (writeback_stat <
540 CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))
541 clear_bdi_congested(&client->backing_dev_info,
542 BLK_RW_ASYNC);
543
Sage Weil80e755f2010-03-31 21:52:10 -0700544 ceph_put_snap_context((void *)page->private);
Sage Weil1d3576f2009-10-06 11:31:09 -0700545 page->private = 0;
546 ClearPagePrivate(page);
Sage Weil1d3576f2009-10-06 11:31:09 -0700547 dout("unlocking %d %p\n", i, page);
548 end_page_writeback(page);
Yehuda Sadehe63dc5c2010-02-19 00:07:01 +0000549
550 /*
551 * We lost the cache cap, need to truncate the page before
552 * it is unlocked, otherwise we'd truncate it later in the
553 * page truncation thread, possibly losing some data that
554 * raced its way in
555 */
Sage Weil29625072010-05-27 10:40:43 -0700556 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
Yehuda Sadehe63dc5c2010-02-19 00:07:01 +0000557 generic_error_remove_page(inode->i_mapping, page);
558
Sage Weil1d3576f2009-10-06 11:31:09 -0700559 unlock_page(page);
560 }
561 dout("%p wrote+cleaned %d pages\n", inode, wrote);
562 ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
563
564 ceph_release_pages(req->r_pages, req->r_num_pages);
565 if (req->r_pages_from_pool)
566 mempool_free(req->r_pages,
Cheng Renquan640ef792010-03-26 17:40:33 +0800567 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
Sage Weil1d3576f2009-10-06 11:31:09 -0700568 else
569 kfree(req->r_pages);
570 ceph_osdc_put_request(req);
571}
572
573/*
574 * allocate a page vec, either directly, or if necessary, via a the
575 * mempool. we avoid the mempool if we can because req->r_num_pages
576 * may be less than the maximum write size.
577 */
578static void alloc_page_vec(struct ceph_client *client,
579 struct ceph_osd_request *req)
580{
581 req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
582 GFP_NOFS);
583 if (!req->r_pages) {
584 req->r_pages = mempool_alloc(client->wb_pagevec_pool, GFP_NOFS);
585 req->r_pages_from_pool = 1;
586 WARN_ON(!req->r_pages);
587 }
588}
589
590/*
591 * initiate async writeback
592 */
593static int ceph_writepages_start(struct address_space *mapping,
594 struct writeback_control *wbc)
595{
596 struct inode *inode = mapping->host;
597 struct backing_dev_info *bdi = mapping->backing_dev_info;
598 struct ceph_inode_info *ci = ceph_inode(inode);
Julia Lawallec7384e2010-01-20 15:16:41 -0800599 struct ceph_client *client;
Sage Weil1d3576f2009-10-06 11:31:09 -0700600 pgoff_t index, start, end;
601 int range_whole = 0;
602 int should_loop = 1;
603 pgoff_t max_pages = 0, max_pages_ever = 0;
Sage Weil80e755f2010-03-31 21:52:10 -0700604 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700605 struct pagevec pvec;
606 int done = 0;
607 int rc = 0;
608 unsigned wsize = 1 << inode->i_blkbits;
609 struct ceph_osd_request *req = NULL;
610 int do_sync;
611 u64 snap_size = 0;
612
613 /*
614 * Include a 'sync' in the OSD request if this is a data
615 * integrity write (e.g., O_SYNC write or fsync()), or if our
616 * cap is being revoked.
617 */
618 do_sync = wbc->sync_mode == WB_SYNC_ALL;
619 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
620 do_sync = 1;
621 dout("writepages_start %p dosync=%d (mode=%s)\n",
622 inode, do_sync,
623 wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
624 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
625
626 client = ceph_inode_to_client(inode);
627 if (client->mount_state == CEPH_MOUNT_SHUTDOWN) {
628 pr_warning("writepage_start %p on forced umount\n", inode);
629 return -EIO; /* we're in a forced umount, don't write! */
630 }
Sage Weil6b805182009-10-27 11:50:50 -0700631 if (client->mount_args->wsize && client->mount_args->wsize < wsize)
632 wsize = client->mount_args->wsize;
Sage Weil1d3576f2009-10-06 11:31:09 -0700633 if (wsize < PAGE_CACHE_SIZE)
634 wsize = PAGE_CACHE_SIZE;
635 max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
636
637 pagevec_init(&pvec, 0);
638
639 /* ?? */
640 if (wbc->nonblocking && bdi_write_congested(bdi)) {
641 dout(" writepages congested\n");
642 wbc->encountered_congestion = 1;
643 goto out_final;
644 }
645
646 /* where to start/end? */
647 if (wbc->range_cyclic) {
648 start = mapping->writeback_index; /* Start from prev offset */
649 end = -1;
650 dout(" cyclic, start at %lu\n", start);
651 } else {
652 start = wbc->range_start >> PAGE_CACHE_SHIFT;
653 end = wbc->range_end >> PAGE_CACHE_SHIFT;
654 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
655 range_whole = 1;
656 should_loop = 0;
657 dout(" not cyclic, %lu to %lu\n", start, end);
658 }
659 index = start;
660
661retry:
662 /* find oldest snap context with dirty data */
663 ceph_put_snap_context(snapc);
664 snapc = get_oldest_context(inode, &snap_size);
665 if (!snapc) {
666 /* hmm, why does writepages get called when there
667 is no dirty data? */
668 dout(" no snap context with dirty data?\n");
669 goto out;
670 }
671 dout(" oldest snapc is %p seq %lld (%d snaps)\n",
672 snapc, snapc->seq, snapc->num_snaps);
673 if (last_snapc && snapc != last_snapc) {
674 /* if we switched to a newer snapc, restart our scan at the
675 * start of the original file range. */
676 dout(" snapc differs from last pass, restarting at %lu\n",
677 index);
678 index = start;
679 }
680 last_snapc = snapc;
681
682 while (!done && index <= end) {
683 unsigned i;
684 int first;
685 pgoff_t next;
686 int pvec_pages, locked_pages;
687 struct page *page;
688 int want;
689 u64 offset, len;
690 struct ceph_osd_request_head *reqhead;
691 struct ceph_osd_op *op;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800692 long writeback_stat;
Sage Weil1d3576f2009-10-06 11:31:09 -0700693
694 next = 0;
695 locked_pages = 0;
696 max_pages = max_pages_ever;
697
698get_more_pages:
699 first = -1;
700 want = min(end - index,
701 min((pgoff_t)PAGEVEC_SIZE,
702 max_pages - (pgoff_t)locked_pages) - 1)
703 + 1;
704 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
705 PAGECACHE_TAG_DIRTY,
706 want);
707 dout("pagevec_lookup_tag got %d\n", pvec_pages);
708 if (!pvec_pages && !locked_pages)
709 break;
710 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
711 page = pvec.pages[i];
712 dout("? %p idx %lu\n", page, page->index);
713 if (locked_pages == 0)
714 lock_page(page); /* first page */
715 else if (!trylock_page(page))
716 break;
717
718 /* only dirty pages, or our accounting breaks */
719 if (unlikely(!PageDirty(page)) ||
720 unlikely(page->mapping != mapping)) {
721 dout("!dirty or !mapping %p\n", page);
722 unlock_page(page);
723 break;
724 }
725 if (!wbc->range_cyclic && page->index > end) {
726 dout("end of range %p\n", page);
727 done = 1;
728 unlock_page(page);
729 break;
730 }
731 if (next && (page->index != next)) {
732 dout("not consecutive %p\n", page);
733 unlock_page(page);
734 break;
735 }
736 if (wbc->sync_mode != WB_SYNC_NONE) {
737 dout("waiting on writeback %p\n", page);
738 wait_on_page_writeback(page);
739 }
740 if ((snap_size && page_offset(page) > snap_size) ||
741 (!snap_size &&
742 page_offset(page) > i_size_read(inode))) {
743 dout("%p page eof %llu\n", page, snap_size ?
744 snap_size : i_size_read(inode));
745 done = 1;
746 unlock_page(page);
747 break;
748 }
749 if (PageWriteback(page)) {
750 dout("%p under writeback\n", page);
751 unlock_page(page);
752 break;
753 }
754
755 /* only if matching snap context */
Sage Weil80e755f2010-03-31 21:52:10 -0700756 pgsnapc = (void *)page->private;
757 if (pgsnapc->seq > snapc->seq) {
758 dout("page snapc %p %lld > oldest %p %lld\n",
759 pgsnapc, pgsnapc->seq, snapc, snapc->seq);
Sage Weil1d3576f2009-10-06 11:31:09 -0700760 unlock_page(page);
761 if (!locked_pages)
762 continue; /* keep looking for snap */
763 break;
764 }
765
766 if (!clear_page_dirty_for_io(page)) {
767 dout("%p !clear_page_dirty_for_io\n", page);
768 unlock_page(page);
769 break;
770 }
771
772 /* ok */
773 if (locked_pages == 0) {
774 /* prepare async write request */
775 offset = page->index << PAGE_CACHE_SHIFT;
776 len = wsize;
777 req = ceph_osdc_new_request(&client->osdc,
778 &ci->i_layout,
779 ceph_vino(inode),
780 offset, &len,
781 CEPH_OSD_OP_WRITE,
782 CEPH_OSD_FLAG_WRITE |
783 CEPH_OSD_FLAG_ONDISK,
784 snapc, do_sync,
785 ci->i_truncate_seq,
786 ci->i_truncate_size,
787 &inode->i_mtime, true, 1);
788 max_pages = req->r_num_pages;
789
790 alloc_page_vec(client, req);
791 req->r_callback = writepages_finish;
792 req->r_inode = inode;
Sage Weil1d3576f2009-10-06 11:31:09 -0700793 }
794
795 /* note position of first page in pvec */
796 if (first < 0)
797 first = i;
798 dout("%p will write page %p idx %lu\n",
799 inode, page, page->index);
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800800
Sage Weil213c99e2010-08-03 10:25:11 -0700801 writeback_stat =
802 atomic_long_inc_return(&client->writeback_count);
803 if (writeback_stat > CONGESTION_ON_THRESH(
804 client->mount_args->congestion_kb)) {
805 set_bdi_congested(&client->backing_dev_info,
806 BLK_RW_ASYNC);
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800807 }
808
Sage Weil1d3576f2009-10-06 11:31:09 -0700809 set_page_writeback(page);
810 req->r_pages[locked_pages] = page;
811 locked_pages++;
812 next = page->index + 1;
813 }
814
815 /* did we get anything? */
816 if (!locked_pages)
817 goto release_pvec_pages;
818 if (i) {
819 int j;
820 BUG_ON(!locked_pages || first < 0);
821
822 if (pvec_pages && i == pvec_pages &&
823 locked_pages < max_pages) {
824 dout("reached end pvec, trying for more\n");
825 pagevec_reinit(&pvec);
826 goto get_more_pages;
827 }
828
829 /* shift unused pages over in the pvec... we
830 * will need to release them below. */
831 for (j = i; j < pvec_pages; j++) {
832 dout(" pvec leftover page %p\n",
833 pvec.pages[j]);
834 pvec.pages[j-i+first] = pvec.pages[j];
835 }
836 pvec.nr -= i-first;
837 }
838
839 /* submit the write */
840 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
841 len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
842 (u64)locked_pages << PAGE_CACHE_SHIFT);
843 dout("writepages got %d pages at %llu~%llu\n",
844 locked_pages, offset, len);
845
846 /* revise final length, page count */
847 req->r_num_pages = locked_pages;
848 reqhead = req->r_request->front.iov_base;
849 op = (void *)(reqhead + 1);
850 op->extent.length = cpu_to_le64(len);
851 op->payload_len = cpu_to_le32(len);
852 req->r_request->hdr.data_len = cpu_to_le32(len);
853
854 ceph_osdc_start_request(&client->osdc, req, true);
855 req = NULL;
856
857 /* continue? */
858 index = next;
859 wbc->nr_to_write -= locked_pages;
860 if (wbc->nr_to_write <= 0)
861 done = 1;
862
863release_pvec_pages:
864 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
865 pvec.nr ? pvec.pages[0] : NULL);
866 pagevec_release(&pvec);
867
868 if (locked_pages && !done)
869 goto retry;
870 }
871
872 if (should_loop && !done) {
873 /* more to do; loop back to beginning of file */
874 dout("writepages looping back to beginning of file\n");
875 should_loop = 0;
876 index = 0;
877 goto retry;
878 }
879
880 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
881 mapping->writeback_index = index;
882
883out:
884 if (req)
885 ceph_osdc_put_request(req);
886 if (rc > 0)
887 rc = 0; /* vfs expects us to return 0 */
888 ceph_put_snap_context(snapc);
889 dout("writepages done, rc = %d\n", rc);
890out_final:
891 return rc;
892}
893
894
895
896/*
897 * See if a given @snapc is either writeable, or already written.
898 */
899static int context_is_writeable_or_written(struct inode *inode,
900 struct ceph_snap_context *snapc)
901{
902 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
Sage Weil6298a332010-03-31 22:01:38 -0700903 int ret = !oldest || snapc->seq <= oldest->seq;
904
905 ceph_put_snap_context(oldest);
906 return ret;
Sage Weil1d3576f2009-10-06 11:31:09 -0700907}
908
909/*
910 * We are only allowed to write into/dirty the page if the page is
911 * clean, or already dirty within the same snap context.
Sage Weil8f883c22010-03-19 13:27:53 -0700912 *
913 * called with page locked.
914 * return success with page locked,
915 * or any failure (incl -EAGAIN) with page unlocked.
Sage Weil1d3576f2009-10-06 11:31:09 -0700916 */
Yehuda Sadeh4af6b222010-02-09 11:02:51 -0800917static int ceph_update_writeable_page(struct file *file,
918 loff_t pos, unsigned len,
919 struct page *page)
Sage Weil1d3576f2009-10-06 11:31:09 -0700920{
921 struct inode *inode = file->f_dentry->d_inode;
922 struct ceph_inode_info *ci = ceph_inode(inode);
923 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700924 loff_t page_off = pos & PAGE_CACHE_MASK;
925 int pos_in_page = pos & ~PAGE_CACHE_MASK;
926 int end_in_page = pos_in_page + len;
927 loff_t i_size;
Sage Weil1d3576f2009-10-06 11:31:09 -0700928 int r;
Sage Weil80e755f2010-03-31 21:52:10 -0700929 struct ceph_snap_context *snapc, *oldest;
Sage Weil1d3576f2009-10-06 11:31:09 -0700930
Sage Weil1d3576f2009-10-06 11:31:09 -0700931retry_locked:
932 /* writepages currently holds page lock, but if we change that later, */
933 wait_on_page_writeback(page);
934
935 /* check snap context */
936 BUG_ON(!ci->i_snap_realm);
937 down_read(&mdsc->snap_rwsem);
938 BUG_ON(!ci->i_snap_realm->cached_context);
Sage Weil80e755f2010-03-31 21:52:10 -0700939 snapc = (void *)page->private;
940 if (snapc && snapc != ci->i_head_snapc) {
Sage Weil1d3576f2009-10-06 11:31:09 -0700941 /*
942 * this page is already dirty in another (older) snap
943 * context! is it writeable now?
944 */
Sage Weil80e755f2010-03-31 21:52:10 -0700945 oldest = get_oldest_context(inode, NULL);
Sage Weil1d3576f2009-10-06 11:31:09 -0700946 up_read(&mdsc->snap_rwsem);
947
Sage Weil80e755f2010-03-31 21:52:10 -0700948 if (snapc->seq > oldest->seq) {
Sage Weil6298a332010-03-31 22:01:38 -0700949 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700950 dout(" page %p snapc %p not current or oldest\n",
Sage Weil6298a332010-03-31 22:01:38 -0700951 page, snapc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700952 /*
953 * queue for writeback, and wait for snapc to
954 * be writeable or written
955 */
Sage Weil6298a332010-03-31 22:01:38 -0700956 snapc = ceph_get_snap_context(snapc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700957 unlock_page(page);
Sage Weil3c6f6b72010-02-09 15:24:44 -0800958 ceph_queue_writeback(inode);
Sage Weil8f883c22010-03-19 13:27:53 -0700959 r = wait_event_interruptible(ci->i_cap_wq,
Sage Weil1d3576f2009-10-06 11:31:09 -0700960 context_is_writeable_or_written(inode, snapc));
961 ceph_put_snap_context(snapc);
Sage Weil8f883c22010-03-19 13:27:53 -0700962 if (r == -ERESTARTSYS)
963 return r;
Yehuda Sadeh4af6b222010-02-09 11:02:51 -0800964 return -EAGAIN;
Sage Weil1d3576f2009-10-06 11:31:09 -0700965 }
Sage Weil6298a332010-03-31 22:01:38 -0700966 ceph_put_snap_context(oldest);
Sage Weil1d3576f2009-10-06 11:31:09 -0700967
968 /* yay, writeable, do it now (without dropping page lock) */
969 dout(" page %p snapc %p not current, but oldest\n",
970 page, snapc);
971 if (!clear_page_dirty_for_io(page))
972 goto retry_locked;
973 r = writepage_nounlock(page, NULL);
974 if (r < 0)
975 goto fail_nosnap;
976 goto retry_locked;
977 }
978
979 if (PageUptodate(page)) {
980 dout(" page %p already uptodate\n", page);
981 return 0;
982 }
983
984 /* full page? */
985 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
986 return 0;
987
988 /* past end of file? */
989 i_size = inode->i_size; /* caller holds i_mutex */
990
991 if (i_size + len > inode->i_sb->s_maxbytes) {
992 /* file is too big */
993 r = -EINVAL;
994 goto fail;
995 }
996
997 if (page_off >= i_size ||
998 (pos_in_page == 0 && (pos+len) >= i_size &&
999 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1000 dout(" zeroing %p 0 - %d and %d - %d\n",
1001 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1002 zero_user_segments(page,
1003 0, pos_in_page,
1004 end_in_page, PAGE_CACHE_SIZE);
1005 return 0;
1006 }
1007
1008 /* we need to read it. */
1009 up_read(&mdsc->snap_rwsem);
1010 r = readpage_nounlock(file, page);
1011 if (r < 0)
1012 goto fail_nosnap;
1013 goto retry_locked;
1014
1015fail:
1016 up_read(&mdsc->snap_rwsem);
1017fail_nosnap:
1018 unlock_page(page);
1019 return r;
1020}
1021
1022/*
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001023 * We are only allowed to write into/dirty the page if the page is
1024 * clean, or already dirty within the same snap context.
1025 */
1026static int ceph_write_begin(struct file *file, struct address_space *mapping,
1027 loff_t pos, unsigned len, unsigned flags,
1028 struct page **pagep, void **fsdata)
1029{
1030 struct inode *inode = file->f_dentry->d_inode;
1031 struct page *page;
1032 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1033 int r;
1034
1035 do {
Sage Weil8f883c22010-03-19 13:27:53 -07001036 /* get a page */
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001037 page = grab_cache_page_write_begin(mapping, index, 0);
1038 if (!page)
1039 return -ENOMEM;
1040 *pagep = page;
1041
1042 dout("write_begin file %p inode %p page %p %d~%d\n", file,
Sage Weil213c99e2010-08-03 10:25:11 -07001043 inode, page, (int)pos, (int)len);
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001044
1045 r = ceph_update_writeable_page(file, pos, len, page);
1046 } while (r == -EAGAIN);
1047
1048 return r;
1049}
1050
1051/*
Sage Weil1d3576f2009-10-06 11:31:09 -07001052 * we don't do anything in here that simple_write_end doesn't do
1053 * except adjust dirty page accounting and drop read lock on
1054 * mdsc->snap_rwsem.
1055 */
1056static int ceph_write_end(struct file *file, struct address_space *mapping,
1057 loff_t pos, unsigned len, unsigned copied,
1058 struct page *page, void *fsdata)
1059{
1060 struct inode *inode = file->f_dentry->d_inode;
Yehuda Sadeh2baba252009-12-18 13:51:57 -08001061 struct ceph_client *client = ceph_inode_to_client(inode);
1062 struct ceph_mds_client *mdsc = &client->mdsc;
Sage Weil1d3576f2009-10-06 11:31:09 -07001063 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1064 int check_cap = 0;
1065
1066 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1067 inode, page, (int)pos, (int)copied, (int)len);
1068
1069 /* zero the stale part of the page if we did a short copy */
1070 if (copied < len)
1071 zero_user_segment(page, from+copied, len);
1072
1073 /* did file size increase? */
1074 /* (no need for i_size_read(); we caller holds i_mutex */
1075 if (pos+copied > inode->i_size)
1076 check_cap = ceph_inode_set_size(inode, pos+copied);
1077
1078 if (!PageUptodate(page))
1079 SetPageUptodate(page);
1080
1081 set_page_dirty(page);
1082
1083 unlock_page(page);
1084 up_read(&mdsc->snap_rwsem);
1085 page_cache_release(page);
1086
1087 if (check_cap)
1088 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1089
1090 return copied;
1091}
1092
1093/*
1094 * we set .direct_IO to indicate direct io is supported, but since we
1095 * intercept O_DIRECT reads and writes early, this function should
1096 * never get called.
1097 */
1098static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1099 const struct iovec *iov,
1100 loff_t pos, unsigned long nr_segs)
1101{
1102 WARN_ON(1);
1103 return -EINVAL;
1104}
1105
1106const struct address_space_operations ceph_aops = {
1107 .readpage = ceph_readpage,
1108 .readpages = ceph_readpages,
1109 .writepage = ceph_writepage,
1110 .writepages = ceph_writepages_start,
1111 .write_begin = ceph_write_begin,
1112 .write_end = ceph_write_end,
1113 .set_page_dirty = ceph_set_page_dirty,
1114 .invalidatepage = ceph_invalidatepage,
1115 .releasepage = ceph_releasepage,
1116 .direct_IO = ceph_direct_io,
1117};
1118
1119
1120/*
1121 * vm ops
1122 */
1123
1124/*
1125 * Reuse write_begin here for simplicity.
1126 */
1127static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1128{
1129 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1130 struct page *page = vmf->page;
1131 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
1132 loff_t off = page->index << PAGE_CACHE_SHIFT;
1133 loff_t size, len;
Sage Weil1d3576f2009-10-06 11:31:09 -07001134 int ret;
1135
1136 size = i_size_read(inode);
1137 if (off + PAGE_CACHE_SIZE <= size)
1138 len = PAGE_CACHE_SIZE;
1139 else
1140 len = size & ~PAGE_CACHE_MASK;
1141
1142 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1143 off, len, page, page->index);
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001144
1145 lock_page(page);
1146
1147 ret = VM_FAULT_NOPAGE;
1148 if ((off > size) ||
1149 (page->mapping != inode->i_mapping))
1150 goto out;
1151
1152 ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1153 if (ret == 0) {
1154 /* success. we'll keep the page locked. */
Sage Weil1d3576f2009-10-06 11:31:09 -07001155 set_page_dirty(page);
1156 up_read(&mdsc->snap_rwsem);
Sage Weil1d3576f2009-10-06 11:31:09 -07001157 ret = VM_FAULT_LOCKED;
1158 } else {
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001159 if (ret == -ENOMEM)
1160 ret = VM_FAULT_OOM;
1161 else
1162 ret = VM_FAULT_SIGBUS;
Sage Weil1d3576f2009-10-06 11:31:09 -07001163 }
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001164out:
Sage Weil1d3576f2009-10-06 11:31:09 -07001165 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
Yehuda Sadeh4af6b222010-02-09 11:02:51 -08001166 if (ret != VM_FAULT_LOCKED)
1167 unlock_page(page);
Sage Weil1d3576f2009-10-06 11:31:09 -07001168 return ret;
1169}
1170
1171static struct vm_operations_struct ceph_vmops = {
1172 .fault = filemap_fault,
1173 .page_mkwrite = ceph_page_mkwrite,
1174};
1175
1176int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1177{
1178 struct address_space *mapping = file->f_mapping;
1179
1180 if (!mapping->a_ops->readpage)
1181 return -ENOEXEC;
1182 file_accessed(file);
1183 vma->vm_ops = &ceph_vmops;
1184 vma->vm_flags |= VM_CAN_NONLINEAR;
1185 return 0;
1186}