blob: a6850a14038e17c88df3c468048716854d1e34bc [file] [log] [blame]
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 */
8#include <linux/pagevec.h>
9#include <linux/task_io_accounting_ops.h>
10
11#include "super.h"
12#include "osd_client.h"
13
14/*
15 * Ceph address space ops.
16 *
17 * There are a few funny things going on here.
18 *
19 * The page->private field is used to reference a struct
20 * ceph_snap_context for _every_ dirty page. This indicates which
21 * snapshot the page was logically dirtied in, and thus which snap
22 * context needs to be associated with the osd write during writeback.
23 *
24 * Similarly, struct ceph_inode_info maintains a set of counters to
25 * count dirty pages on the inode. In the absense of snapshots,
26 * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
27 *
28 * When a snapshot is taken (that is, when the client receives
29 * notification that a snapshot was taken), each inode with caps and
30 * with dirty pages (dirty pages implies there is a cap) gets a new
31 * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
32 * order, new snaps go to the tail). The i_wrbuffer_ref_head count is
33 * moved to capsnap->dirty. (Unless a sync write is currently in
34 * progress. In that case, the capsnap is said to be "pending", new
35 * writes cannot start, and the capsnap isn't "finalized" until the
36 * write completes (or fails) and a final size/mtime for the inode for
37 * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0.
38 *
39 * On writeback, we must submit writes to the osd IN SNAP ORDER. So,
40 * we look for the first capsnap in i_cap_snaps and write out pages in
41 * that snap context _only_. Then we move on to the next capsnap,
42 * eventually reaching the "live" or "head" context (i.e., pages that
43 * are not yet snapped) and are writing the most recently dirtied
44 * pages.
45 *
46 * Invalidate and so forth must take care to ensure the dirty page
47 * accounting is preserved.
48 */
49
Yehuda Sadeh2baba252009-12-18 13:51:57 -080050#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
51#define CONGESTION_OFF_THRESH(congestion_kb) \
52 (CONGESTION_ON_THRESH(congestion_kb) - \
53 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
54
55
Sage Weil1d3576f2009-10-06 11:31:09 -070056
57/*
58 * Dirty a page. Optimistically adjust accounting, on the assumption
59 * that we won't race with invalidate. If we do, readjust.
60 */
61static int ceph_set_page_dirty(struct page *page)
62{
63 struct address_space *mapping = page->mapping;
64 struct inode *inode;
65 struct ceph_inode_info *ci;
66 int undo = 0;
67 struct ceph_snap_context *snapc;
68
69 if (unlikely(!mapping))
70 return !TestSetPageDirty(page);
71
72 if (TestSetPageDirty(page)) {
73 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
74 mapping->host, page, page->index);
75 return 0;
76 }
77
78 inode = mapping->host;
79 ci = ceph_inode(inode);
80
81 /*
82 * Note that we're grabbing a snapc ref here without holding
83 * any locks!
84 */
85 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
86
87 /* dirty the head */
88 spin_lock(&inode->i_lock);
89 if (ci->i_wrbuffer_ref_head == 0)
90 ci->i_head_snapc = ceph_get_snap_context(snapc);
91 ++ci->i_wrbuffer_ref_head;
92 if (ci->i_wrbuffer_ref == 0)
93 igrab(inode);
94 ++ci->i_wrbuffer_ref;
95 dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
96 "snapc %p seq %lld (%d snaps)\n",
97 mapping->host, page, page->index,
98 ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
99 ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
100 snapc, snapc->seq, snapc->num_snaps);
101 spin_unlock(&inode->i_lock);
102
103 /* now adjust page */
104 spin_lock_irq(&mapping->tree_lock);
105 if (page->mapping) { /* Race with truncate? */
106 WARN_ON_ONCE(!PageUptodate(page));
107
108 if (mapping_cap_account_dirty(mapping)) {
109 __inc_zone_page_state(page, NR_FILE_DIRTY);
110 __inc_bdi_stat(mapping->backing_dev_info,
111 BDI_RECLAIMABLE);
112 task_io_account_write(PAGE_CACHE_SIZE);
113 }
114 radix_tree_tag_set(&mapping->page_tree,
115 page_index(page), PAGECACHE_TAG_DIRTY);
116
117 /*
118 * Reference snap context in page->private. Also set
119 * PagePrivate so that we get invalidatepage callback.
120 */
121 page->private = (unsigned long)snapc;
122 SetPagePrivate(page);
123 } else {
124 dout("ANON set_page_dirty %p (raced truncate?)\n", page);
125 undo = 1;
126 }
127
128 spin_unlock_irq(&mapping->tree_lock);
129
130 if (undo)
131 /* whoops, we failed to dirty the page */
132 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
133
134 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
135
136 BUG_ON(!PageDirty(page));
137 return 1;
138}
139
140/*
141 * If we are truncating the full page (i.e. offset == 0), adjust the
142 * dirty page counters appropriately. Only called if there is private
143 * data on the page.
144 */
145static void ceph_invalidatepage(struct page *page, unsigned long offset)
146{
147 struct inode *inode = page->mapping->host;
148 struct ceph_inode_info *ci;
149 struct ceph_snap_context *snapc = (void *)page->private;
150
151 BUG_ON(!PageLocked(page));
152 BUG_ON(!page->private);
153 BUG_ON(!PagePrivate(page));
154 BUG_ON(!page->mapping);
155
156 /*
157 * We can get non-dirty pages here due to races between
158 * set_page_dirty and truncate_complete_page; just spit out a
159 * warning, in case we end up with accounting problems later.
160 */
161 if (!PageDirty(page))
162 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
163
164 if (offset == 0)
165 ClearPageChecked(page);
166
167 ci = ceph_inode(inode);
168 if (offset == 0) {
169 dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
170 inode, page, page->index, offset);
171 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
172 ceph_put_snap_context(snapc);
173 page->private = 0;
174 ClearPagePrivate(page);
175 } else {
176 dout("%p invalidatepage %p idx %lu partial dirty page\n",
177 inode, page, page->index);
178 }
179}
180
181/* just a sanity check */
182static int ceph_releasepage(struct page *page, gfp_t g)
183{
184 struct inode *inode = page->mapping ? page->mapping->host : NULL;
185 dout("%p releasepage %p idx %lu\n", inode, page, page->index);
186 WARN_ON(PageDirty(page));
187 WARN_ON(page->private);
188 WARN_ON(PagePrivate(page));
189 return 0;
190}
191
192/*
193 * read a single page, without unlocking it.
194 */
195static int readpage_nounlock(struct file *filp, struct page *page)
196{
197 struct inode *inode = filp->f_dentry->d_inode;
198 struct ceph_inode_info *ci = ceph_inode(inode);
199 struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
200 int err = 0;
201 u64 len = PAGE_CACHE_SIZE;
202
203 dout("readpage inode %p file %p page %p index %lu\n",
204 inode, filp, page, page->index);
205 err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
206 page->index << PAGE_CACHE_SHIFT, &len,
207 ci->i_truncate_seq, ci->i_truncate_size,
208 &page, 1);
209 if (err == -ENOENT)
210 err = 0;
211 if (err < 0) {
212 SetPageError(page);
213 goto out;
214 } else if (err < PAGE_CACHE_SIZE) {
215 /* zero fill remainder of page */
216 zero_user_segment(page, err, PAGE_CACHE_SIZE);
217 }
218 SetPageUptodate(page);
219
220out:
221 return err < 0 ? err : 0;
222}
223
224static int ceph_readpage(struct file *filp, struct page *page)
225{
226 int r = readpage_nounlock(filp, page);
227 unlock_page(page);
228 return r;
229}
230
231/*
232 * Build a vector of contiguous pages from the provided page list.
233 */
234static struct page **page_vector_from_list(struct list_head *page_list,
235 unsigned *nr_pages)
236{
237 struct page **pages;
238 struct page *page;
239 int next_index, contig_pages = 0;
240
241 /* build page vector */
242 pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
243 if (!pages)
244 return ERR_PTR(-ENOMEM);
245
246 BUG_ON(list_empty(page_list));
247 next_index = list_entry(page_list->prev, struct page, lru)->index;
248 list_for_each_entry_reverse(page, page_list, lru) {
249 if (page->index == next_index) {
250 dout("readpages page %d %p\n", contig_pages, page);
251 pages[contig_pages] = page;
252 contig_pages++;
253 next_index++;
254 } else {
255 break;
256 }
257 }
258 *nr_pages = contig_pages;
259 return pages;
260}
261
262/*
263 * Read multiple pages. Leave pages we don't read + unlock in page_list;
264 * the caller (VM) cleans them up.
265 */
266static int ceph_readpages(struct file *file, struct address_space *mapping,
267 struct list_head *page_list, unsigned nr_pages)
268{
269 struct inode *inode = file->f_dentry->d_inode;
270 struct ceph_inode_info *ci = ceph_inode(inode);
271 struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
272 int rc = 0;
273 struct page **pages;
274 struct pagevec pvec;
275 loff_t offset;
276 u64 len;
277
278 dout("readpages %p file %p nr_pages %d\n",
279 inode, file, nr_pages);
280
281 pages = page_vector_from_list(page_list, &nr_pages);
282 if (IS_ERR(pages))
283 return PTR_ERR(pages);
284
285 /* guess read extent */
286 offset = pages[0]->index << PAGE_CACHE_SHIFT;
287 len = nr_pages << PAGE_CACHE_SHIFT;
288 rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
289 offset, &len,
290 ci->i_truncate_seq, ci->i_truncate_size,
291 pages, nr_pages);
292 if (rc == -ENOENT)
293 rc = 0;
294 if (rc < 0)
295 goto out;
296
297 /* set uptodate and add to lru in pagevec-sized chunks */
298 pagevec_init(&pvec, 0);
299 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
312 if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) {
313 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);
323 if (pagevec_add(&pvec, page) == 0)
324 pagevec_lru_add_file(&pvec); /* add to lru */
325 }
326 pagevec_lru_add_file(&pvec);
327 rc = 0;
328
329out:
330 kfree(pages);
331 return rc;
332}
333
334/*
335 * Get ref for the oldest snapc for an inode with dirty data... that is, the
336 * only snap context we are allowed to write back.
337 *
338 * Caller holds i_lock.
339 */
340static struct ceph_snap_context *__get_oldest_context(struct inode *inode,
341 u64 *snap_size)
342{
343 struct ceph_inode_info *ci = ceph_inode(inode);
344 struct ceph_snap_context *snapc = NULL;
345 struct ceph_cap_snap *capsnap = NULL;
346
347 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
348 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
349 capsnap->context, capsnap->dirty_pages);
350 if (capsnap->dirty_pages) {
351 snapc = ceph_get_snap_context(capsnap->context);
352 if (snap_size)
353 *snap_size = capsnap->size;
354 break;
355 }
356 }
357 if (!snapc && ci->i_snap_realm) {
358 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
359 dout(" head snapc %p has %d dirty pages\n",
360 snapc, ci->i_wrbuffer_ref_head);
361 }
362 return snapc;
363}
364
365static struct ceph_snap_context *get_oldest_context(struct inode *inode,
366 u64 *snap_size)
367{
368 struct ceph_snap_context *snapc = NULL;
369
370 spin_lock(&inode->i_lock);
371 snapc = __get_oldest_context(inode, snap_size);
372 spin_unlock(&inode->i_lock);
373 return snapc;
374}
375
376/*
377 * Write a single page, but leave the page locked.
378 *
379 * If we get a write error, set the page error bit, but still adjust the
380 * dirty page accounting (i.e., page is no longer dirty).
381 */
382static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
383{
384 struct inode *inode;
385 struct ceph_inode_info *ci;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800386 struct ceph_client *client;
Sage Weil1d3576f2009-10-06 11:31:09 -0700387 struct ceph_osd_client *osdc;
388 loff_t page_off = page->index << PAGE_CACHE_SHIFT;
389 int len = PAGE_CACHE_SIZE;
390 loff_t i_size;
391 int err = 0;
392 struct ceph_snap_context *snapc;
393 u64 snap_size = 0;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800394 long writeback_stat;
Sage Weil1d3576f2009-10-06 11:31:09 -0700395
396 dout("writepage %p idx %lu\n", page, page->index);
397
398 if (!page->mapping || !page->mapping->host) {
399 dout("writepage %p - no mapping\n", page);
400 return -EFAULT;
401 }
402 inode = page->mapping->host;
403 ci = ceph_inode(inode);
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800404 client = ceph_inode_to_client(inode);
405 osdc = &client->osdc;
Sage Weil1d3576f2009-10-06 11:31:09 -0700406
407 /* verify this is a writeable snap context */
408 snapc = (void *)page->private;
409 if (snapc == NULL) {
410 dout("writepage %p page %p not dirty?\n", inode, page);
411 goto out;
412 }
413 if (snapc != get_oldest_context(inode, &snap_size)) {
414 dout("writepage %p page %p snapc %p not writeable - noop\n",
415 inode, page, (void *)page->private);
416 /* we should only noop if called by kswapd */
417 WARN_ON((current->flags & PF_MEMALLOC) == 0);
418 goto out;
419 }
420
421 /* is this a partial page at end of file? */
422 if (snap_size)
423 i_size = snap_size;
424 else
425 i_size = i_size_read(inode);
426 if (i_size < page_off + len)
427 len = i_size - page_off;
428
429 dout("writepage %p page %p index %lu on %llu~%u\n",
430 inode, page, page->index, page_off, len);
431
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800432 writeback_stat = atomic_long_inc_return(&client->writeback_count);
433 if (writeback_stat >
434 CONGESTION_ON_THRESH(client->mount_args->congestion_kb))
435 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
436
Sage Weil1d3576f2009-10-06 11:31:09 -0700437 set_page_writeback(page);
438 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
439 &ci->i_layout, snapc,
440 page_off, len,
441 ci->i_truncate_seq, ci->i_truncate_size,
442 &inode->i_mtime,
443 &page, 1, 0, 0, true);
444 if (err < 0) {
445 dout("writepage setting page/mapping error %d %p\n", err, page);
446 SetPageError(page);
447 mapping_set_error(&inode->i_data, err);
448 if (wbc)
449 wbc->pages_skipped++;
450 } else {
451 dout("writepage cleaned page %p\n", page);
452 err = 0; /* vfs expects us to return 0 */
453 }
454 page->private = 0;
455 ClearPagePrivate(page);
456 end_page_writeback(page);
457 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
458 ceph_put_snap_context(snapc);
459out:
460 return err;
461}
462
463static int ceph_writepage(struct page *page, struct writeback_control *wbc)
464{
Yehuda Sadehdbd646a2009-12-16 14:51:06 -0800465 int err;
466 struct inode *inode = page->mapping->host;
467 BUG_ON(!inode);
468 igrab(inode);
469 err = writepage_nounlock(page, wbc);
Sage Weil1d3576f2009-10-06 11:31:09 -0700470 unlock_page(page);
Yehuda Sadehdbd646a2009-12-16 14:51:06 -0800471 iput(inode);
Sage Weil1d3576f2009-10-06 11:31:09 -0700472 return err;
473}
474
475
476/*
477 * lame release_pages helper. release_pages() isn't exported to
478 * modules.
479 */
480static void ceph_release_pages(struct page **pages, int num)
481{
482 struct pagevec pvec;
483 int i;
484
485 pagevec_init(&pvec, 0);
486 for (i = 0; i < num; i++) {
487 if (pagevec_add(&pvec, pages[i]) == 0)
488 pagevec_release(&pvec);
489 }
490 pagevec_release(&pvec);
491}
492
493
494/*
495 * async writeback completion handler.
496 *
497 * If we get an error, set the mapping error bit, but not the individual
498 * page error bits.
499 */
500static void writepages_finish(struct ceph_osd_request *req,
501 struct ceph_msg *msg)
502{
503 struct inode *inode = req->r_inode;
504 struct ceph_osd_reply_head *replyhead;
505 struct ceph_osd_op *op;
506 struct ceph_inode_info *ci = ceph_inode(inode);
507 unsigned wrote;
508 loff_t offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
509 struct page *page;
510 int i;
511 struct ceph_snap_context *snapc = req->r_snapc;
512 struct address_space *mapping = inode->i_mapping;
513 struct writeback_control *wbc = req->r_wbc;
514 __s32 rc = -EIO;
515 u64 bytes = 0;
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800516 struct ceph_client *client = ceph_inode_to_client(inode);
517 long writeback_stat;
Sage Weil1d3576f2009-10-06 11:31:09 -0700518
519 /* parse reply */
520 replyhead = msg->front.iov_base;
521 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
522 op = (void *)(replyhead + 1);
523 rc = le32_to_cpu(replyhead->result);
524 bytes = le64_to_cpu(op->extent.length);
525
526 if (rc >= 0) {
527 wrote = (bytes + (offset & ~PAGE_CACHE_MASK) + ~PAGE_CACHE_MASK)
528 >> PAGE_CACHE_SHIFT;
529 WARN_ON(wrote != req->r_num_pages);
530 } else {
531 wrote = 0;
532 mapping_set_error(mapping, rc);
533 }
534 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
535 inode, rc, bytes, wrote);
536
537 /* clean all pages */
538 for (i = 0; i < req->r_num_pages; i++) {
539 page = req->r_pages[i];
540 BUG_ON(!page);
541 WARN_ON(!PageUptodate(page));
542
Yehuda Sadeh2baba252009-12-18 13:51:57 -0800543 writeback_stat =
544 atomic_long_dec_return(&client->writeback_count);
545 if (writeback_stat <
546 CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))
547 clear_bdi_congested(&client->backing_dev_info,
548 BLK_RW_ASYNC);
549
Sage Weil1d3576f2009-10-06 11:31:09 -0700550 if (i >= wrote) {
551 dout("inode %p skipping page %p\n", inode, page);
552 wbc->pages_skipped++;
553 }
554 page->private = 0;
555 ClearPagePrivate(page);
556 ceph_put_snap_context(snapc);
557 dout("unlocking %d %p\n", i, page);
558 end_page_writeback(page);
559 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,
567 ceph_client(inode->i_sb)->wb_pagevec_pool);
568 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);
599 struct ceph_client *client = ceph_inode_to_client(inode);
600 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;
604 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL;
605 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 */
756 if (snapc != (void *)page->private) {
757 dout("page snapc %p != oldest %p\n",
758 (void *)page->private, snapc);
759 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;
792 req->r_wbc = wbc;
793 }
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
801 writeback_stat = atomic_long_inc_return(&client->writeback_count);
802 if (writeback_stat > CONGESTION_ON_THRESH(client->mount_args->congestion_kb)) {
803 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
804 }
805
Sage Weil1d3576f2009-10-06 11:31:09 -0700806 set_page_writeback(page);
807 req->r_pages[locked_pages] = page;
808 locked_pages++;
809 next = page->index + 1;
810 }
811
812 /* did we get anything? */
813 if (!locked_pages)
814 goto release_pvec_pages;
815 if (i) {
816 int j;
817 BUG_ON(!locked_pages || first < 0);
818
819 if (pvec_pages && i == pvec_pages &&
820 locked_pages < max_pages) {
821 dout("reached end pvec, trying for more\n");
822 pagevec_reinit(&pvec);
823 goto get_more_pages;
824 }
825
826 /* shift unused pages over in the pvec... we
827 * will need to release them below. */
828 for (j = i; j < pvec_pages; j++) {
829 dout(" pvec leftover page %p\n",
830 pvec.pages[j]);
831 pvec.pages[j-i+first] = pvec.pages[j];
832 }
833 pvec.nr -= i-first;
834 }
835
836 /* submit the write */
837 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
838 len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
839 (u64)locked_pages << PAGE_CACHE_SHIFT);
840 dout("writepages got %d pages at %llu~%llu\n",
841 locked_pages, offset, len);
842
843 /* revise final length, page count */
844 req->r_num_pages = locked_pages;
845 reqhead = req->r_request->front.iov_base;
846 op = (void *)(reqhead + 1);
847 op->extent.length = cpu_to_le64(len);
848 op->payload_len = cpu_to_le32(len);
849 req->r_request->hdr.data_len = cpu_to_le32(len);
850
851 ceph_osdc_start_request(&client->osdc, req, true);
852 req = NULL;
853
854 /* continue? */
855 index = next;
856 wbc->nr_to_write -= locked_pages;
857 if (wbc->nr_to_write <= 0)
858 done = 1;
859
860release_pvec_pages:
861 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
862 pvec.nr ? pvec.pages[0] : NULL);
863 pagevec_release(&pvec);
864
865 if (locked_pages && !done)
866 goto retry;
867 }
868
869 if (should_loop && !done) {
870 /* more to do; loop back to beginning of file */
871 dout("writepages looping back to beginning of file\n");
872 should_loop = 0;
873 index = 0;
874 goto retry;
875 }
876
877 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
878 mapping->writeback_index = index;
879
880out:
881 if (req)
882 ceph_osdc_put_request(req);
883 if (rc > 0)
884 rc = 0; /* vfs expects us to return 0 */
885 ceph_put_snap_context(snapc);
886 dout("writepages done, rc = %d\n", rc);
887out_final:
888 return rc;
889}
890
891
892
893/*
894 * See if a given @snapc is either writeable, or already written.
895 */
896static int context_is_writeable_or_written(struct inode *inode,
897 struct ceph_snap_context *snapc)
898{
899 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
900 return !oldest || snapc->seq <= oldest->seq;
901}
902
903/*
904 * We are only allowed to write into/dirty the page if the page is
905 * clean, or already dirty within the same snap context.
906 */
907static int ceph_write_begin(struct file *file, struct address_space *mapping,
908 loff_t pos, unsigned len, unsigned flags,
909 struct page **pagep, void **fsdata)
910{
911 struct inode *inode = file->f_dentry->d_inode;
912 struct ceph_inode_info *ci = ceph_inode(inode);
913 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
914 struct page *page;
915 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
916 loff_t page_off = pos & PAGE_CACHE_MASK;
917 int pos_in_page = pos & ~PAGE_CACHE_MASK;
918 int end_in_page = pos_in_page + len;
919 loff_t i_size;
920 struct ceph_snap_context *snapc;
921 int r;
922
923 /* get a page*/
924retry:
925 page = grab_cache_page_write_begin(mapping, index, 0);
926 if (!page)
927 return -ENOMEM;
928 *pagep = page;
929
930 dout("write_begin file %p inode %p page %p %d~%d\n", file,
931 inode, page, (int)pos, (int)len);
932
933retry_locked:
934 /* writepages currently holds page lock, but if we change that later, */
935 wait_on_page_writeback(page);
936
937 /* check snap context */
938 BUG_ON(!ci->i_snap_realm);
939 down_read(&mdsc->snap_rwsem);
940 BUG_ON(!ci->i_snap_realm->cached_context);
941 if (page->private &&
942 (void *)page->private != ci->i_snap_realm->cached_context) {
943 /*
944 * this page is already dirty in another (older) snap
945 * context! is it writeable now?
946 */
947 snapc = get_oldest_context(inode, NULL);
948 up_read(&mdsc->snap_rwsem);
949
950 if (snapc != (void *)page->private) {
951 dout(" page %p snapc %p not current or oldest\n",
952 page, (void *)page->private);
953 /*
954 * queue for writeback, and wait for snapc to
955 * be writeable or written
956 */
957 snapc = ceph_get_snap_context((void *)page->private);
958 unlock_page(page);
959 if (ceph_queue_writeback(inode))
960 igrab(inode);
961 wait_event_interruptible(ci->i_cap_wq,
962 context_is_writeable_or_written(inode, snapc));
963 ceph_put_snap_context(snapc);
964 goto retry;
965 }
966
967 /* yay, writeable, do it now (without dropping page lock) */
968 dout(" page %p snapc %p not current, but oldest\n",
969 page, snapc);
970 if (!clear_page_dirty_for_io(page))
971 goto retry_locked;
972 r = writepage_nounlock(page, NULL);
973 if (r < 0)
974 goto fail_nosnap;
975 goto retry_locked;
976 }
977
978 if (PageUptodate(page)) {
979 dout(" page %p already uptodate\n", page);
980 return 0;
981 }
982
983 /* full page? */
984 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
985 return 0;
986
987 /* past end of file? */
988 i_size = inode->i_size; /* caller holds i_mutex */
989
990 if (i_size + len > inode->i_sb->s_maxbytes) {
991 /* file is too big */
992 r = -EINVAL;
993 goto fail;
994 }
995
996 if (page_off >= i_size ||
997 (pos_in_page == 0 && (pos+len) >= i_size &&
998 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
999 dout(" zeroing %p 0 - %d and %d - %d\n",
1000 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1001 zero_user_segments(page,
1002 0, pos_in_page,
1003 end_in_page, PAGE_CACHE_SIZE);
1004 return 0;
1005 }
1006
1007 /* we need to read it. */
1008 up_read(&mdsc->snap_rwsem);
1009 r = readpage_nounlock(file, page);
1010 if (r < 0)
1011 goto fail_nosnap;
1012 goto retry_locked;
1013
1014fail:
1015 up_read(&mdsc->snap_rwsem);
1016fail_nosnap:
1017 unlock_page(page);
1018 return r;
1019}
1020
1021/*
1022 * we don't do anything in here that simple_write_end doesn't do
1023 * except adjust dirty page accounting and drop read lock on
1024 * mdsc->snap_rwsem.
1025 */
1026static int ceph_write_end(struct file *file, struct address_space *mapping,
1027 loff_t pos, unsigned len, unsigned copied,
1028 struct page *page, void *fsdata)
1029{
1030 struct inode *inode = file->f_dentry->d_inode;
Yehuda Sadeh2baba252009-12-18 13:51:57 -08001031 struct ceph_client *client = ceph_inode_to_client(inode);
1032 struct ceph_mds_client *mdsc = &client->mdsc;
Sage Weil1d3576f2009-10-06 11:31:09 -07001033 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1034 int check_cap = 0;
1035
1036 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1037 inode, page, (int)pos, (int)copied, (int)len);
1038
1039 /* zero the stale part of the page if we did a short copy */
1040 if (copied < len)
1041 zero_user_segment(page, from+copied, len);
1042
1043 /* did file size increase? */
1044 /* (no need for i_size_read(); we caller holds i_mutex */
1045 if (pos+copied > inode->i_size)
1046 check_cap = ceph_inode_set_size(inode, pos+copied);
1047
1048 if (!PageUptodate(page))
1049 SetPageUptodate(page);
1050
1051 set_page_dirty(page);
1052
1053 unlock_page(page);
1054 up_read(&mdsc->snap_rwsem);
1055 page_cache_release(page);
1056
1057 if (check_cap)
1058 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1059
1060 return copied;
1061}
1062
1063/*
1064 * we set .direct_IO to indicate direct io is supported, but since we
1065 * intercept O_DIRECT reads and writes early, this function should
1066 * never get called.
1067 */
1068static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1069 const struct iovec *iov,
1070 loff_t pos, unsigned long nr_segs)
1071{
1072 WARN_ON(1);
1073 return -EINVAL;
1074}
1075
1076const struct address_space_operations ceph_aops = {
1077 .readpage = ceph_readpage,
1078 .readpages = ceph_readpages,
1079 .writepage = ceph_writepage,
1080 .writepages = ceph_writepages_start,
1081 .write_begin = ceph_write_begin,
1082 .write_end = ceph_write_end,
1083 .set_page_dirty = ceph_set_page_dirty,
1084 .invalidatepage = ceph_invalidatepage,
1085 .releasepage = ceph_releasepage,
1086 .direct_IO = ceph_direct_io,
1087};
1088
1089
1090/*
1091 * vm ops
1092 */
1093
1094/*
1095 * Reuse write_begin here for simplicity.
1096 */
1097static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1098{
1099 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1100 struct page *page = vmf->page;
1101 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
1102 loff_t off = page->index << PAGE_CACHE_SHIFT;
1103 loff_t size, len;
1104 struct page *locked_page = NULL;
1105 void *fsdata = NULL;
1106 int ret;
1107
1108 size = i_size_read(inode);
1109 if (off + PAGE_CACHE_SIZE <= size)
1110 len = PAGE_CACHE_SIZE;
1111 else
1112 len = size & ~PAGE_CACHE_MASK;
1113
1114 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1115 off, len, page, page->index);
1116 ret = ceph_write_begin(vma->vm_file, inode->i_mapping, off, len, 0,
1117 &locked_page, &fsdata);
1118 WARN_ON(page != locked_page);
1119 if (!ret) {
1120 /*
1121 * doing the following, instead of calling
1122 * ceph_write_end. Note that we keep the
1123 * page locked
1124 */
1125 set_page_dirty(page);
1126 up_read(&mdsc->snap_rwsem);
1127 page_cache_release(page);
1128 ret = VM_FAULT_LOCKED;
1129 } else {
1130 ret = VM_FAULT_SIGBUS;
1131 }
1132 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1133 return ret;
1134}
1135
1136static struct vm_operations_struct ceph_vmops = {
1137 .fault = filemap_fault,
1138 .page_mkwrite = ceph_page_mkwrite,
1139};
1140
1141int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1142{
1143 struct address_space *mapping = file->f_mapping;
1144
1145 if (!mapping->a_ops->readpage)
1146 return -ENOEXEC;
1147 file_accessed(file);
1148 vma->vm_ops = &ceph_vmops;
1149 vma->vm_flags |= VM_CAN_NONLINEAR;
1150 return 0;
1151}