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-rw-r--r--fs/ceph/addr.c1187
1 files changed, 1187 insertions, 0 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
new file mode 100644
index 000000000000..a9005d862ed4
--- /dev/null
+++ b/fs/ceph/addr.c
@@ -0,0 +1,1187 @@
1#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/slab.h>
9#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
51#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
57
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{
148 struct inode *inode;
149 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
157 inode = page->mapping->host;
158
159 /*
160 * We can get non-dirty pages here due to races between
161 * set_page_dirty and truncate_complete_page; just spit out a
162 * warning, in case we end up with accounting problems later.
163 */
164 if (!PageDirty(page))
165 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
166
167 if (offset == 0)
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;
277 struct pagevec pvec;
278 loff_t offset;
279 u64 len;
280
281 dout("readpages %p file %p nr_pages %d\n",
282 inode, file, nr_pages);
283
284 pages = page_vector_from_list(page_list, &nr_pages);
285 if (IS_ERR(pages))
286 return PTR_ERR(pages);
287
288 /* guess read extent */
289 offset = pages[0]->index << PAGE_CACHE_SHIFT;
290 len = nr_pages << PAGE_CACHE_SHIFT;
291 rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
292 offset, &len,
293 ci->i_truncate_seq, ci->i_truncate_size,
294 pages, nr_pages);
295 if (rc == -ENOENT)
296 rc = 0;
297 if (rc < 0)
298 goto out;
299
300 /* set uptodate and add to lru in pagevec-sized chunks */
301 pagevec_init(&pvec, 0);
302 for (; !list_empty(page_list) && len > 0;
303 rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
304 struct page *page =
305 list_entry(page_list->prev, struct page, lru);
306
307 list_del(&page->lru);
308
309 if (rc < (int)PAGE_CACHE_SIZE) {
310 /* zero (remainder of) page */
311 int s = rc < 0 ? 0 : rc;
312 zero_user_segment(page, s, PAGE_CACHE_SIZE);
313 }
314
315 if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) {
316 page_cache_release(page);
317 dout("readpages %p add_to_page_cache failed %p\n",
318 inode, page);
319 continue;
320 }
321 dout("readpages %p adding %p idx %lu\n", inode, page,
322 page->index);
323 flush_dcache_page(page);
324 SetPageUptodate(page);
325 unlock_page(page);
326 if (pagevec_add(&pvec, page) == 0)
327 pagevec_lru_add_file(&pvec); /* add to lru */
328 }
329 pagevec_lru_add_file(&pvec);
330 rc = 0;
331
332out:
333 kfree(pages);
334 return rc;
335}
336
337/*
338 * Get ref for the oldest snapc for an inode with dirty data... that is, the
339 * only snap context we are allowed to write back.
340 */
341static struct ceph_snap_context *get_oldest_context(struct inode *inode,
342 u64 *snap_size)
343{
344 struct ceph_inode_info *ci = ceph_inode(inode);
345 struct ceph_snap_context *snapc = NULL;
346 struct ceph_cap_snap *capsnap = NULL;
347
348 spin_lock(&inode->i_lock);
349 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
350 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
351 capsnap->context, capsnap->dirty_pages);
352 if (capsnap->dirty_pages) {
353 snapc = ceph_get_snap_context(capsnap->context);
354 if (snap_size)
355 *snap_size = capsnap->size;
356 break;
357 }
358 }
359 if (!snapc && ci->i_head_snapc) {
360 snapc = ceph_get_snap_context(ci->i_head_snapc);
361 dout(" head snapc %p has %d dirty pages\n",
362 snapc, ci->i_wrbuffer_ref_head);
363 }
364 spin_unlock(&inode->i_lock);
365 return snapc;
366}
367
368/*
369 * Write a single page, but leave the page locked.
370 *
371 * If we get a write error, set the page error bit, but still adjust the
372 * dirty page accounting (i.e., page is no longer dirty).
373 */
374static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
375{
376 struct inode *inode;
377 struct ceph_inode_info *ci;
378 struct ceph_client *client;
379 struct ceph_osd_client *osdc;
380 loff_t page_off = page->index << PAGE_CACHE_SHIFT;
381 int len = PAGE_CACHE_SIZE;
382 loff_t i_size;
383 int err = 0;
384 struct ceph_snap_context *snapc, *oldest;
385 u64 snap_size = 0;
386 long writeback_stat;
387
388 dout("writepage %p idx %lu\n", page, page->index);
389
390 if (!page->mapping || !page->mapping->host) {
391 dout("writepage %p - no mapping\n", page);
392 return -EFAULT;
393 }
394 inode = page->mapping->host;
395 ci = ceph_inode(inode);
396 client = ceph_inode_to_client(inode);
397 osdc = &client->osdc;
398
399 /* verify this is a writeable snap context */
400 snapc = (void *)page->private;
401 if (snapc == NULL) {
402 dout("writepage %p page %p not dirty?\n", inode, page);
403 goto out;
404 }
405 oldest = get_oldest_context(inode, &snap_size);
406 if (snapc->seq > oldest->seq) {
407 dout("writepage %p page %p snapc %p not writeable - noop\n",
408 inode, page, (void *)page->private);
409 /* we should only noop if called by kswapd */
410 WARN_ON((current->flags & PF_MEMALLOC) == 0);
411 ceph_put_snap_context(oldest);
412 goto out;
413 }
414 ceph_put_snap_context(oldest);
415
416 /* is this a partial page at end of file? */
417 if (snap_size)
418 i_size = snap_size;
419 else
420 i_size = i_size_read(inode);
421 if (i_size < page_off + len)
422 len = i_size - page_off;
423
424 dout("writepage %p page %p index %lu on %llu~%u\n",
425 inode, page, page->index, page_off, len);
426
427 writeback_stat = atomic_long_inc_return(&client->writeback_count);
428 if (writeback_stat >
429 CONGESTION_ON_THRESH(client->mount_args->congestion_kb))
430 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
431
432 set_page_writeback(page);
433 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
434 &ci->i_layout, snapc,
435 page_off, len,
436 ci->i_truncate_seq, ci->i_truncate_size,
437 &inode->i_mtime,
438 &page, 1, 0, 0, true);
439 if (err < 0) {
440 dout("writepage setting page/mapping error %d %p\n", err, page);
441 SetPageError(page);
442 mapping_set_error(&inode->i_data, err);
443 if (wbc)
444 wbc->pages_skipped++;
445 } else {
446 dout("writepage cleaned page %p\n", page);
447 err = 0; /* vfs expects us to return 0 */
448 }
449 page->private = 0;
450 ClearPagePrivate(page);
451 end_page_writeback(page);
452 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
453 ceph_put_snap_context(snapc); /* page's reference */
454out:
455 return err;
456}
457
458static int ceph_writepage(struct page *page, struct writeback_control *wbc)
459{
460 int err;
461 struct inode *inode = page->mapping->host;
462 BUG_ON(!inode);
463 igrab(inode);
464 err = writepage_nounlock(page, wbc);
465 unlock_page(page);
466 iput(inode);
467 return err;
468}
469
470
471/*
472 * lame release_pages helper. release_pages() isn't exported to
473 * modules.
474 */
475static void ceph_release_pages(struct page **pages, int num)
476{
477 struct pagevec pvec;
478 int i;
479
480 pagevec_init(&pvec, 0);
481 for (i = 0; i < num; i++) {
482 if (pagevec_add(&pvec, pages[i]) == 0)
483 pagevec_release(&pvec);
484 }
485 pagevec_release(&pvec);
486}
487
488
489/*
490 * async writeback completion handler.
491 *
492 * If we get an error, set the mapping error bit, but not the individual
493 * page error bits.
494 */
495static void writepages_finish(struct ceph_osd_request *req,
496 struct ceph_msg *msg)
497{
498 struct inode *inode = req->r_inode;
499 struct ceph_osd_reply_head *replyhead;
500 struct ceph_osd_op *op;
501 struct ceph_inode_info *ci = ceph_inode(inode);
502 unsigned wrote;
503 struct page *page;
504 int i;
505 struct ceph_snap_context *snapc = req->r_snapc;
506 struct address_space *mapping = inode->i_mapping;
507 __s32 rc = -EIO;
508 u64 bytes = 0;
509 struct ceph_client *client = ceph_inode_to_client(inode);
510 long writeback_stat;
511 unsigned issued = ceph_caps_issued(ci);
512
513 /* parse reply */
514 replyhead = msg->front.iov_base;
515 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
516 op = (void *)(replyhead + 1);
517 rc = le32_to_cpu(replyhead->result);
518 bytes = le64_to_cpu(op->extent.length);
519
520 if (rc >= 0) {
521 /*
522 * Assume we wrote the pages we originally sent. The
523 * osd might reply with fewer pages if our writeback
524 * raced with a truncation and was adjusted at the osd,
525 * so don't believe the reply.
526 */
527 wrote = req->r_num_pages;
528 } else {
529 wrote = 0;
530 mapping_set_error(mapping, rc);
531 }
532 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
533 inode, rc, bytes, wrote);
534
535 /* clean all pages */
536 for (i = 0; i < req->r_num_pages; i++) {
537 page = req->r_pages[i];
538 BUG_ON(!page);
539 WARN_ON(!PageUptodate(page));
540
541 writeback_stat =
542 atomic_long_dec_return(&client->writeback_count);
543 if (writeback_stat <
544 CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))
545 clear_bdi_congested(&client->backing_dev_info,
546 BLK_RW_ASYNC);
547
548 ceph_put_snap_context((void *)page->private);
549 page->private = 0;
550 ClearPagePrivate(page);
551 dout("unlocking %d %p\n", i, page);
552 end_page_writeback(page);
553
554 /*
555 * We lost the cache cap, need to truncate the page before
556 * it is unlocked, otherwise we'd truncate it later in the
557 * page truncation thread, possibly losing some data that
558 * raced its way in
559 */
560 if ((issued & CEPH_CAP_FILE_CACHE) == 0)
561 generic_error_remove_page(inode->i_mapping, page);
562
563 unlock_page(page);
564 }
565 dout("%p wrote+cleaned %d pages\n", inode, wrote);
566 ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
567
568 ceph_release_pages(req->r_pages, req->r_num_pages);
569 if (req->r_pages_from_pool)
570 mempool_free(req->r_pages,
571 ceph_client(inode->i_sb)->wb_pagevec_pool);
572 else
573 kfree(req->r_pages);
574 ceph_osdc_put_request(req);
575}
576
577/*
578 * allocate a page vec, either directly, or if necessary, via a the
579 * mempool. we avoid the mempool if we can because req->r_num_pages
580 * may be less than the maximum write size.
581 */
582static void alloc_page_vec(struct ceph_client *client,
583 struct ceph_osd_request *req)
584{
585 req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
586 GFP_NOFS);
587 if (!req->r_pages) {
588 req->r_pages = mempool_alloc(client->wb_pagevec_pool, GFP_NOFS);
589 req->r_pages_from_pool = 1;
590 WARN_ON(!req->r_pages);
591 }
592}
593
594/*
595 * initiate async writeback
596 */
597static int ceph_writepages_start(struct address_space *mapping,
598 struct writeback_control *wbc)
599{
600 struct inode *inode = mapping->host;
601 struct backing_dev_info *bdi = mapping->backing_dev_info;
602 struct ceph_inode_info *ci = ceph_inode(inode);
603 struct ceph_client *client;
604 pgoff_t index, start, end;
605 int range_whole = 0;
606 int should_loop = 1;
607 pgoff_t max_pages = 0, max_pages_ever = 0;
608 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
609 struct pagevec pvec;
610 int done = 0;
611 int rc = 0;
612 unsigned wsize = 1 << inode->i_blkbits;
613 struct ceph_osd_request *req = NULL;
614 int do_sync;
615 u64 snap_size = 0;
616
617 /*
618 * Include a 'sync' in the OSD request if this is a data
619 * integrity write (e.g., O_SYNC write or fsync()), or if our
620 * cap is being revoked.
621 */
622 do_sync = wbc->sync_mode == WB_SYNC_ALL;
623 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
624 do_sync = 1;
625 dout("writepages_start %p dosync=%d (mode=%s)\n",
626 inode, do_sync,
627 wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
628 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
629
630 client = ceph_inode_to_client(inode);
631 if (client->mount_state == CEPH_MOUNT_SHUTDOWN) {
632 pr_warning("writepage_start %p on forced umount\n", inode);
633 return -EIO; /* we're in a forced umount, don't write! */
634 }
635 if (client->mount_args->wsize && client->mount_args->wsize < wsize)
636 wsize = client->mount_args->wsize;
637 if (wsize < PAGE_CACHE_SIZE)
638 wsize = PAGE_CACHE_SIZE;
639 max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
640
641 pagevec_init(&pvec, 0);
642
643 /* ?? */
644 if (wbc->nonblocking && bdi_write_congested(bdi)) {
645 dout(" writepages congested\n");
646 wbc->encountered_congestion = 1;
647 goto out_final;
648 }
649
650 /* where to start/end? */
651 if (wbc->range_cyclic) {
652 start = mapping->writeback_index; /* Start from prev offset */
653 end = -1;
654 dout(" cyclic, start at %lu\n", start);
655 } else {
656 start = wbc->range_start >> PAGE_CACHE_SHIFT;
657 end = wbc->range_end >> PAGE_CACHE_SHIFT;
658 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
659 range_whole = 1;
660 should_loop = 0;
661 dout(" not cyclic, %lu to %lu\n", start, end);
662 }
663 index = start;
664
665retry:
666 /* find oldest snap context with dirty data */
667 ceph_put_snap_context(snapc);
668 snapc = get_oldest_context(inode, &snap_size);
669 if (!snapc) {
670 /* hmm, why does writepages get called when there
671 is no dirty data? */
672 dout(" no snap context with dirty data?\n");
673 goto out;
674 }
675 dout(" oldest snapc is %p seq %lld (%d snaps)\n",
676 snapc, snapc->seq, snapc->num_snaps);
677 if (last_snapc && snapc != last_snapc) {
678 /* if we switched to a newer snapc, restart our scan at the
679 * start of the original file range. */
680 dout(" snapc differs from last pass, restarting at %lu\n",
681 index);
682 index = start;
683 }
684 last_snapc = snapc;
685
686 while (!done && index <= end) {
687 unsigned i;
688 int first;
689 pgoff_t next;
690 int pvec_pages, locked_pages;
691 struct page *page;
692 int want;
693 u64 offset, len;
694 struct ceph_osd_request_head *reqhead;
695 struct ceph_osd_op *op;
696 long writeback_stat;
697
698 next = 0;
699 locked_pages = 0;
700 max_pages = max_pages_ever;
701
702get_more_pages:
703 first = -1;
704 want = min(end - index,
705 min((pgoff_t)PAGEVEC_SIZE,
706 max_pages - (pgoff_t)locked_pages) - 1)
707 + 1;
708 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
709 PAGECACHE_TAG_DIRTY,
710 want);
711 dout("pagevec_lookup_tag got %d\n", pvec_pages);
712 if (!pvec_pages && !locked_pages)
713 break;
714 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
715 page = pvec.pages[i];
716 dout("? %p idx %lu\n", page, page->index);
717 if (locked_pages == 0)
718 lock_page(page); /* first page */
719 else if (!trylock_page(page))
720 break;
721
722 /* only dirty pages, or our accounting breaks */
723 if (unlikely(!PageDirty(page)) ||
724 unlikely(page->mapping != mapping)) {
725 dout("!dirty or !mapping %p\n", page);
726 unlock_page(page);
727 break;
728 }
729 if (!wbc->range_cyclic && page->index > end) {
730 dout("end of range %p\n", page);
731 done = 1;
732 unlock_page(page);
733 break;
734 }
735 if (next && (page->index != next)) {
736 dout("not consecutive %p\n", page);
737 unlock_page(page);
738 break;
739 }
740 if (wbc->sync_mode != WB_SYNC_NONE) {
741 dout("waiting on writeback %p\n", page);
742 wait_on_page_writeback(page);
743 }
744 if ((snap_size && page_offset(page) > snap_size) ||
745 (!snap_size &&
746 page_offset(page) > i_size_read(inode))) {
747 dout("%p page eof %llu\n", page, snap_size ?
748 snap_size : i_size_read(inode));
749 done = 1;
750 unlock_page(page);
751 break;
752 }
753 if (PageWriteback(page)) {
754 dout("%p under writeback\n", page);
755 unlock_page(page);
756 break;
757 }
758
759 /* only if matching snap context */
760 pgsnapc = (void *)page->private;
761 if (pgsnapc->seq > snapc->seq) {
762 dout("page snapc %p %lld > oldest %p %lld\n",
763 pgsnapc, pgsnapc->seq, snapc, snapc->seq);
764 unlock_page(page);
765 if (!locked_pages)
766 continue; /* keep looking for snap */
767 break;
768 }
769
770 if (!clear_page_dirty_for_io(page)) {
771 dout("%p !clear_page_dirty_for_io\n", page);
772 unlock_page(page);
773 break;
774 }
775
776 /* ok */
777 if (locked_pages == 0) {
778 /* prepare async write request */
779 offset = page->index << PAGE_CACHE_SHIFT;
780 len = wsize;
781 req = ceph_osdc_new_request(&client->osdc,
782 &ci->i_layout,
783 ceph_vino(inode),
784 offset, &len,
785 CEPH_OSD_OP_WRITE,
786 CEPH_OSD_FLAG_WRITE |
787 CEPH_OSD_FLAG_ONDISK,
788 snapc, do_sync,
789 ci->i_truncate_seq,
790 ci->i_truncate_size,
791 &inode->i_mtime, true, 1);
792 max_pages = req->r_num_pages;
793
794 alloc_page_vec(client, req);
795 req->r_callback = writepages_finish;
796 req->r_inode = inode;
797 }
798
799 /* note position of first page in pvec */
800 if (first < 0)
801 first = i;
802 dout("%p will write page %p idx %lu\n",
803 inode, page, page->index);
804
805 writeback_stat = atomic_long_inc_return(&client->writeback_count);
806 if (writeback_stat > CONGESTION_ON_THRESH(client->mount_args->congestion_kb)) {
807 set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
808 }
809
810 set_page_writeback(page);
811 req->r_pages[locked_pages] = page;
812 locked_pages++;
813 next = page->index + 1;
814 }
815
816 /* did we get anything? */
817 if (!locked_pages)
818 goto release_pvec_pages;
819 if (i) {
820 int j;
821 BUG_ON(!locked_pages || first < 0);
822
823 if (pvec_pages && i == pvec_pages &&
824 locked_pages < max_pages) {
825 dout("reached end pvec, trying for more\n");
826 pagevec_reinit(&pvec);
827 goto get_more_pages;
828 }
829
830 /* shift unused pages over in the pvec... we
831 * will need to release them below. */
832 for (j = i; j < pvec_pages; j++) {
833 dout(" pvec leftover page %p\n",
834 pvec.pages[j]);
835 pvec.pages[j-i+first] = pvec.pages[j];
836 }
837 pvec.nr -= i-first;
838 }
839
840 /* submit the write */
841 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
842 len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
843 (u64)locked_pages << PAGE_CACHE_SHIFT);
844 dout("writepages got %d pages at %llu~%llu\n",
845 locked_pages, offset, len);
846
847 /* revise final length, page count */
848 req->r_num_pages = locked_pages;
849 reqhead = req->r_request->front.iov_base;
850 op = (void *)(reqhead + 1);
851 op->extent.length = cpu_to_le64(len);
852 op->payload_len = cpu_to_le32(len);
853 req->r_request->hdr.data_len = cpu_to_le32(len);
854
855 ceph_osdc_start_request(&client->osdc, req, true);
856 req = NULL;
857
858 /* continue? */
859 index = next;
860 wbc->nr_to_write -= locked_pages;
861 if (wbc->nr_to_write <= 0)
862 done = 1;
863
864release_pvec_pages:
865 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
866 pvec.nr ? pvec.pages[0] : NULL);
867 pagevec_release(&pvec);
868
869 if (locked_pages && !done)
870 goto retry;
871 }
872
873 if (should_loop && !done) {
874 /* more to do; loop back to beginning of file */
875 dout("writepages looping back to beginning of file\n");
876 should_loop = 0;
877 index = 0;
878 goto retry;
879 }
880
881 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
882 mapping->writeback_index = index;
883
884out:
885 if (req)
886 ceph_osdc_put_request(req);
887 if (rc > 0)
888 rc = 0; /* vfs expects us to return 0 */
889 ceph_put_snap_context(snapc);
890 dout("writepages done, rc = %d\n", rc);
891out_final:
892 return rc;
893}
894
895
896
897/*
898 * See if a given @snapc is either writeable, or already written.
899 */
900static int context_is_writeable_or_written(struct inode *inode,
901 struct ceph_snap_context *snapc)
902{
903 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
904 int ret = !oldest || snapc->seq <= oldest->seq;
905
906 ceph_put_snap_context(oldest);
907 return ret;
908}
909
910/*
911 * We are only allowed to write into/dirty the page if the page is
912 * clean, or already dirty within the same snap context.
913 *
914 * called with page locked.
915 * return success with page locked,
916 * or any failure (incl -EAGAIN) with page unlocked.
917 */
918static int ceph_update_writeable_page(struct file *file,
919 loff_t pos, unsigned len,
920 struct page *page)
921{
922 struct inode *inode = file->f_dentry->d_inode;
923 struct ceph_inode_info *ci = ceph_inode(inode);
924 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
925 loff_t page_off = pos & PAGE_CACHE_MASK;
926 int pos_in_page = pos & ~PAGE_CACHE_MASK;
927 int end_in_page = pos_in_page + len;
928 loff_t i_size;
929 int r;
930 struct ceph_snap_context *snapc, *oldest;
931
932retry_locked:
933 /* writepages currently holds page lock, but if we change that later, */
934 wait_on_page_writeback(page);
935
936 /* check snap context */
937 BUG_ON(!ci->i_snap_realm);
938 down_read(&mdsc->snap_rwsem);
939 BUG_ON(!ci->i_snap_realm->cached_context);
940 snapc = (void *)page->private;
941 if (snapc && snapc != ci->i_head_snapc) {
942 /*
943 * this page is already dirty in another (older) snap
944 * context! is it writeable now?
945 */
946 oldest = get_oldest_context(inode, NULL);
947 up_read(&mdsc->snap_rwsem);
948
949 if (snapc->seq > oldest->seq) {
950 ceph_put_snap_context(oldest);
951 dout(" page %p snapc %p not current or oldest\n",
952 page, snapc);
953 /*
954 * queue for writeback, and wait for snapc to
955 * be writeable or written
956 */
957 snapc = ceph_get_snap_context(snapc);
958 unlock_page(page);
959 ceph_queue_writeback(inode);
960 r = wait_event_interruptible(ci->i_cap_wq,
961 context_is_writeable_or_written(inode, snapc));
962 ceph_put_snap_context(snapc);
963 if (r == -ERESTARTSYS)
964 return r;
965 return -EAGAIN;
966 }
967 ceph_put_snap_context(oldest);
968
969 /* yay, writeable, do it now (without dropping page lock) */
970 dout(" page %p snapc %p not current, but oldest\n",
971 page, snapc);
972 if (!clear_page_dirty_for_io(page))
973 goto retry_locked;
974 r = writepage_nounlock(page, NULL);
975 if (r < 0)
976 goto fail_nosnap;
977 goto retry_locked;
978 }
979
980 if (PageUptodate(page)) {
981 dout(" page %p already uptodate\n", page);
982 return 0;
983 }
984
985 /* full page? */
986 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
987 return 0;
988
989 /* past end of file? */
990 i_size = inode->i_size; /* caller holds i_mutex */
991
992 if (i_size + len > inode->i_sb->s_maxbytes) {
993 /* file is too big */
994 r = -EINVAL;
995 goto fail;
996 }
997
998 if (page_off >= i_size ||
999 (pos_in_page == 0 && (pos+len) >= i_size &&
1000 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1001 dout(" zeroing %p 0 - %d and %d - %d\n",
1002 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1003 zero_user_segments(page,
1004 0, pos_in_page,
1005 end_in_page, PAGE_CACHE_SIZE);
1006 return 0;
1007 }
1008
1009 /* we need to read it. */
1010 up_read(&mdsc->snap_rwsem);
1011 r = readpage_nounlock(file, page);
1012 if (r < 0)
1013 goto fail_nosnap;
1014 goto retry_locked;
1015
1016fail:
1017 up_read(&mdsc->snap_rwsem);
1018fail_nosnap:
1019 unlock_page(page);
1020 return r;
1021}
1022
1023/*
1024 * We are only allowed to write into/dirty the page if the page is
1025 * clean, or already dirty within the same snap context.
1026 */
1027static int ceph_write_begin(struct file *file, struct address_space *mapping,
1028 loff_t pos, unsigned len, unsigned flags,
1029 struct page **pagep, void **fsdata)
1030{
1031 struct inode *inode = file->f_dentry->d_inode;
1032 struct page *page;
1033 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1034 int r;
1035
1036 do {
1037 /* get a page */
1038 page = grab_cache_page_write_begin(mapping, index, 0);
1039 if (!page)
1040 return -ENOMEM;
1041 *pagep = page;
1042
1043 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1044 inode, page, (int)pos, (int)len);
1045
1046 r = ceph_update_writeable_page(file, pos, len, page);
1047 } while (r == -EAGAIN);
1048
1049 return r;
1050}
1051
1052/*
1053 * we don't do anything in here that simple_write_end doesn't do
1054 * except adjust dirty page accounting and drop read lock on
1055 * mdsc->snap_rwsem.
1056 */
1057static int ceph_write_end(struct file *file, struct address_space *mapping,
1058 loff_t pos, unsigned len, unsigned copied,
1059 struct page *page, void *fsdata)
1060{
1061 struct inode *inode = file->f_dentry->d_inode;
1062 struct ceph_client *client = ceph_inode_to_client(inode);
1063 struct ceph_mds_client *mdsc = &client->mdsc;
1064 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1065 int check_cap = 0;
1066
1067 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1068 inode, page, (int)pos, (int)copied, (int)len);
1069
1070 /* zero the stale part of the page if we did a short copy */
1071 if (copied < len)
1072 zero_user_segment(page, from+copied, len);
1073
1074 /* did file size increase? */
1075 /* (no need for i_size_read(); we caller holds i_mutex */
1076 if (pos+copied > inode->i_size)
1077 check_cap = ceph_inode_set_size(inode, pos+copied);
1078
1079 if (!PageUptodate(page))
1080 SetPageUptodate(page);
1081
1082 set_page_dirty(page);
1083
1084 unlock_page(page);
1085 up_read(&mdsc->snap_rwsem);
1086 page_cache_release(page);
1087
1088 if (check_cap)
1089 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1090
1091 return copied;
1092}
1093
1094/*
1095 * we set .direct_IO to indicate direct io is supported, but since we
1096 * intercept O_DIRECT reads and writes early, this function should
1097 * never get called.
1098 */
1099static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1100 const struct iovec *iov,
1101 loff_t pos, unsigned long nr_segs)
1102{
1103 WARN_ON(1);
1104 return -EINVAL;
1105}
1106
1107const struct address_space_operations ceph_aops = {
1108 .readpage = ceph_readpage,
1109 .readpages = ceph_readpages,
1110 .writepage = ceph_writepage,
1111 .writepages = ceph_writepages_start,
1112 .write_begin = ceph_write_begin,
1113 .write_end = ceph_write_end,
1114 .set_page_dirty = ceph_set_page_dirty,
1115 .invalidatepage = ceph_invalidatepage,
1116 .releasepage = ceph_releasepage,
1117 .direct_IO = ceph_direct_io,
1118};
1119
1120
1121/*
1122 * vm ops
1123 */
1124
1125/*
1126 * Reuse write_begin here for simplicity.
1127 */
1128static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1129{
1130 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1131 struct page *page = vmf->page;
1132 struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
1133 loff_t off = page->index << PAGE_CACHE_SHIFT;
1134 loff_t size, len;
1135 int ret;
1136
1137 size = i_size_read(inode);
1138 if (off + PAGE_CACHE_SIZE <= size)
1139 len = PAGE_CACHE_SIZE;
1140 else
1141 len = size & ~PAGE_CACHE_MASK;
1142
1143 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1144 off, len, page, page->index);
1145
1146 lock_page(page);
1147
1148 ret = VM_FAULT_NOPAGE;
1149 if ((off > size) ||
1150 (page->mapping != inode->i_mapping))
1151 goto out;
1152
1153 ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1154 if (ret == 0) {
1155 /* success. we'll keep the page locked. */
1156 set_page_dirty(page);
1157 up_read(&mdsc->snap_rwsem);
1158 ret = VM_FAULT_LOCKED;
1159 } else {
1160 if (ret == -ENOMEM)
1161 ret = VM_FAULT_OOM;
1162 else
1163 ret = VM_FAULT_SIGBUS;
1164 }
1165out:
1166 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1167 if (ret != VM_FAULT_LOCKED)
1168 unlock_page(page);
1169 return ret;
1170}
1171
1172static struct vm_operations_struct ceph_vmops = {
1173 .fault = filemap_fault,
1174 .page_mkwrite = ceph_page_mkwrite,
1175};
1176
1177int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1178{
1179 struct address_space *mapping = file->f_mapping;
1180
1181 if (!mapping->a_ops->readpage)
1182 return -ENOEXEC;
1183 file_accessed(file);
1184 vma->vm_ops = &ceph_vmops;
1185 vma->vm_flags |= VM_CAN_NONLINEAR;
1186 return 0;
1187}
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-12 08:01:08 -0400