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1#include <linux/ceph/ceph_debug.h>
2
3#include <linux/backing-dev.h>
4#include <linux/fs.h>
5#include <linux/mm.h>
6#include <linux/pagemap.h>
7#include <linux/writeback.h> /* generic_writepages */
8#include <linux/slab.h>
9#include <linux/pagevec.h>
10#include <linux/task_io_accounting_ops.h>
11
12#include "super.h"
13#include "mds_client.h"
14#include <linux/ceph/osd_client.h>
15
16/*
17 * Ceph address space ops.
18 *
19 * There are a few funny things going on here.
20 *
21 * The page->private field is used to reference a struct
22 * ceph_snap_context for _every_ dirty page. This indicates which
23 * snapshot the page was logically dirtied in, and thus which snap
24 * context needs to be associated with the osd write during writeback.
25 *
26 * Similarly, struct ceph_inode_info maintains a set of counters to
27 * count dirty pages on the inode. In the absence of snapshots,
28 * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
29 *
30 * When a snapshot is taken (that is, when the client receives
31 * notification that a snapshot was taken), each inode with caps and
32 * with dirty pages (dirty pages implies there is a cap) gets a new
33 * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
34 * order, new snaps go to the tail). The i_wrbuffer_ref_head count is
35 * moved to capsnap->dirty. (Unless a sync write is currently in
36 * progress. In that case, the capsnap is said to be "pending", new
37 * writes cannot start, and the capsnap isn't "finalized" until the
38 * write completes (or fails) and a final size/mtime for the inode for
39 * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0.
40 *
41 * On writeback, we must submit writes to the osd IN SNAP ORDER. So,
42 * we look for the first capsnap in i_cap_snaps and write out pages in
43 * that snap context _only_. Then we move on to the next capsnap,
44 * eventually reaching the "live" or "head" context (i.e., pages that
45 * are not yet snapped) and are writing the most recently dirtied
46 * pages.
47 *
48 * Invalidate and so forth must take care to ensure the dirty page
49 * accounting is preserved.
50 */
51
52#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
53#define CONGESTION_OFF_THRESH(congestion_kb) \
54 (CONGESTION_ON_THRESH(congestion_kb) - \
55 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
56
57static inline struct ceph_snap_context *page_snap_context(struct page *page)
58{
59 if (PagePrivate(page))
60 return (void *)page->private;
61 return NULL;
62}
63
64/*
65 * Dirty a page. Optimistically adjust accounting, on the assumption
66 * that we won't race with invalidate. If we do, readjust.
67 */
68static int ceph_set_page_dirty(struct page *page)
69{
70 struct address_space *mapping = page->mapping;
71 struct inode *inode;
72 struct ceph_inode_info *ci;
73 int undo = 0;
74 struct ceph_snap_context *snapc;
75
76 if (unlikely(!mapping))
77 return !TestSetPageDirty(page);
78
79 if (TestSetPageDirty(page)) {
80 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
81 mapping->host, page, page->index);
82 return 0;
83 }
84
85 inode = mapping->host;
86 ci = ceph_inode(inode);
87
88 /*
89 * Note that we're grabbing a snapc ref here without holding
90 * any locks!
91 */
92 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
93
94 /* dirty the head */
95 spin_lock(&ci->i_ceph_lock);
96 if (ci->i_head_snapc == NULL)
97 ci->i_head_snapc = ceph_get_snap_context(snapc);
98 ++ci->i_wrbuffer_ref_head;
99 if (ci->i_wrbuffer_ref == 0)
100 ihold(inode);
101 ++ci->i_wrbuffer_ref;
102 dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
103 "snapc %p seq %lld (%d snaps)\n",
104 mapping->host, page, page->index,
105 ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
106 ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
107 snapc, snapc->seq, snapc->num_snaps);
108 spin_unlock(&ci->i_ceph_lock);
109
110 /* now adjust page */
111 spin_lock_irq(&mapping->tree_lock);
112 if (page->mapping) { /* Race with truncate? */
113 WARN_ON_ONCE(!PageUptodate(page));
114 account_page_dirtied(page, page->mapping);
115 radix_tree_tag_set(&mapping->page_tree,
116 page_index(page), PAGECACHE_TAG_DIRTY);
117
118 /*
119 * Reference snap context in page->private. Also set
120 * PagePrivate so that we get invalidatepage callback.
121 */
122 page->private = (unsigned long)snapc;
123 SetPagePrivate(page);
124 } else {
125 dout("ANON set_page_dirty %p (raced truncate?)\n", page);
126 undo = 1;
127 }
128
129 spin_unlock_irq(&mapping->tree_lock);
130
131 if (undo)
132 /* whoops, we failed to dirty the page */
133 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
134
135 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
136
137 BUG_ON(!PageDirty(page));
138 return 1;
139}
140
141/*
142 * If we are truncating the full page (i.e. offset == 0), adjust the
143 * dirty page counters appropriately. Only called if there is private
144 * data on the page.
145 */
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 = page_snap_context(page);
151
152 BUG_ON(!PageLocked(page));
153 BUG_ON(!PagePrivate(page));
154 BUG_ON(!page->mapping);
155
156 inode = page->mapping->host;
157
158 /*
159 * We can get non-dirty pages here due to races between
160 * set_page_dirty and truncate_complete_page; just spit out a
161 * warning, in case we end up with accounting problems later.
162 */
163 if (!PageDirty(page))
164 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
165
166 if (offset == 0)
167 ClearPageChecked(page);
168
169 ci = ceph_inode(inode);
170 if (offset == 0) {
171 dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
172 inode, page, page->index, offset);
173 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
174 ceph_put_snap_context(snapc);
175 page->private = 0;
176 ClearPagePrivate(page);
177 } else {
178 dout("%p invalidatepage %p idx %lu partial dirty page\n",
179 inode, page, page->index);
180 }
181}
182
183/* just a sanity check */
184static int ceph_releasepage(struct page *page, gfp_t g)
185{
186 struct inode *inode = page->mapping ? page->mapping->host : NULL;
187 dout("%p releasepage %p idx %lu\n", inode, page, page->index);
188 WARN_ON(PageDirty(page));
189 WARN_ON(PagePrivate(page));
190 return 0;
191}
192
193/*
194 * read a single page, without unlocking it.
195 */
196static int readpage_nounlock(struct file *filp, struct page *page)
197{
198 struct inode *inode = filp->f_dentry->d_inode;
199 struct ceph_inode_info *ci = ceph_inode(inode);
200 struct ceph_osd_client *osdc =
201 &ceph_inode_to_client(inode)->client->osdc;
202 int err = 0;
203 u64 len = PAGE_CACHE_SIZE;
204
205 dout("readpage inode %p file %p page %p index %lu\n",
206 inode, filp, page, page->index);
207 err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
208 page->index << PAGE_CACHE_SHIFT, &len,
209 ci->i_truncate_seq, ci->i_truncate_size,
210 &page, 1, 0);
211 if (err == -ENOENT)
212 err = 0;
213 if (err < 0) {
214 SetPageError(page);
215 goto out;
216 } else if (err < PAGE_CACHE_SIZE) {
217 /* zero fill remainder of page */
218 zero_user_segment(page, err, PAGE_CACHE_SIZE);
219 }
220 SetPageUptodate(page);
221
222out:
223 return err < 0 ? err : 0;
224}
225
226static int ceph_readpage(struct file *filp, struct page *page)
227{
228 int r = readpage_nounlock(filp, page);
229 unlock_page(page);
230 return r;
231}
232
233/*
234 * Finish an async read(ahead) op.
235 */
236static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
237{
238 struct inode *inode = req->r_inode;
239 struct ceph_osd_reply_head *replyhead;
240 int rc, bytes;
241 int i;
242
243 /* parse reply */
244 replyhead = msg->front.iov_base;
245 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
246 rc = le32_to_cpu(replyhead->result);
247 bytes = le32_to_cpu(msg->hdr.data_len);
248
249 dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
250
251 /* unlock all pages, zeroing any data we didn't read */
252 for (i = 0; i < req->r_num_pages; i++, bytes -= PAGE_CACHE_SIZE) {
253 struct page *page = req->r_pages[i];
254
255 if (bytes < (int)PAGE_CACHE_SIZE) {
256 /* zero (remainder of) page */
257 int s = bytes < 0 ? 0 : bytes;
258 zero_user_segment(page, s, PAGE_CACHE_SIZE);
259 }
260 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
261 page->index);
262 flush_dcache_page(page);
263 SetPageUptodate(page);
264 unlock_page(page);
265 page_cache_release(page);
266 }
267 kfree(req->r_pages);
268}
269
270/*
271 * start an async read(ahead) operation. return nr_pages we submitted
272 * a read for on success, or negative error code.
273 */
274static int start_read(struct inode *inode, struct list_head *page_list, int max)
275{
276 struct ceph_osd_client *osdc =
277 &ceph_inode_to_client(inode)->client->osdc;
278 struct ceph_inode_info *ci = ceph_inode(inode);
279 struct page *page = list_entry(page_list->prev, struct page, lru);
280 struct ceph_osd_request *req;
281 u64 off;
282 u64 len;
283 int i;
284 struct page **pages;
285 pgoff_t next_index;
286 int nr_pages = 0;
287 int ret;
288
289 off = page->index << PAGE_CACHE_SHIFT;
290
291 /* count pages */
292 next_index = page->index;
293 list_for_each_entry_reverse(page, page_list, lru) {
294 if (page->index != next_index)
295 break;
296 nr_pages++;
297 next_index++;
298 if (max && nr_pages == max)
299 break;
300 }
301 len = nr_pages << PAGE_CACHE_SHIFT;
302 dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
303 off, len);
304
305 req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode),
306 off, &len,
307 CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ,
308 NULL, 0,
309 ci->i_truncate_seq, ci->i_truncate_size,
310 NULL, false, 1, 0);
311 if (!req)
312 return -ENOMEM;
313
314 /* build page vector */
315 nr_pages = len >> PAGE_CACHE_SHIFT;
316 pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
317 ret = -ENOMEM;
318 if (!pages)
319 goto out;
320 for (i = 0; i < nr_pages; ++i) {
321 page = list_entry(page_list->prev, struct page, lru);
322 BUG_ON(PageLocked(page));
323 list_del(&page->lru);
324
325 dout("start_read %p adding %p idx %lu\n", inode, page,
326 page->index);
327 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
328 GFP_NOFS)) {
329 page_cache_release(page);
330 dout("start_read %p add_to_page_cache failed %p\n",
331 inode, page);
332 nr_pages = i;
333 goto out_pages;
334 }
335 pages[i] = page;
336 }
337 req->r_pages = pages;
338 req->r_num_pages = nr_pages;
339 req->r_callback = finish_read;
340 req->r_inode = inode;
341
342 dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
343 ret = ceph_osdc_start_request(osdc, req, false);
344 if (ret < 0)
345 goto out_pages;
346 ceph_osdc_put_request(req);
347 return nr_pages;
348
349out_pages:
350 ceph_release_page_vector(pages, nr_pages);
351out:
352 ceph_osdc_put_request(req);
353 return ret;
354}
355
356
357/*
358 * Read multiple pages. Leave pages we don't read + unlock in page_list;
359 * the caller (VM) cleans them up.
360 */
361static int ceph_readpages(struct file *file, struct address_space *mapping,
362 struct list_head *page_list, unsigned nr_pages)
363{
364 struct inode *inode = file->f_dentry->d_inode;
365 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
366 int rc = 0;
367 int max = 0;
368
369 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
370 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
371 >> PAGE_SHIFT;
372
373 dout("readpages %p file %p nr_pages %d max %d\n", inode, file, nr_pages,
374 max);
375 while (!list_empty(page_list)) {
376 rc = start_read(inode, page_list, max);
377 if (rc < 0)
378 goto out;
379 BUG_ON(rc == 0);
380 }
381out:
382 dout("readpages %p file %p ret %d\n", inode, file, rc);
383 return rc;
384}
385
386/*
387 * Get ref for the oldest snapc for an inode with dirty data... that is, the
388 * only snap context we are allowed to write back.
389 */
390static struct ceph_snap_context *get_oldest_context(struct inode *inode,
391 u64 *snap_size)
392{
393 struct ceph_inode_info *ci = ceph_inode(inode);
394 struct ceph_snap_context *snapc = NULL;
395 struct ceph_cap_snap *capsnap = NULL;
396
397 spin_lock(&ci->i_ceph_lock);
398 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
399 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
400 capsnap->context, capsnap->dirty_pages);
401 if (capsnap->dirty_pages) {
402 snapc = ceph_get_snap_context(capsnap->context);
403 if (snap_size)
404 *snap_size = capsnap->size;
405 break;
406 }
407 }
408 if (!snapc && ci->i_wrbuffer_ref_head) {
409 snapc = ceph_get_snap_context(ci->i_head_snapc);
410 dout(" head snapc %p has %d dirty pages\n",
411 snapc, ci->i_wrbuffer_ref_head);
412 }
413 spin_unlock(&ci->i_ceph_lock);
414 return snapc;
415}
416
417/*
418 * Write a single page, but leave the page locked.
419 *
420 * If we get a write error, set the page error bit, but still adjust the
421 * dirty page accounting (i.e., page is no longer dirty).
422 */
423static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
424{
425 struct inode *inode;
426 struct ceph_inode_info *ci;
427 struct ceph_fs_client *fsc;
428 struct ceph_osd_client *osdc;
429 loff_t page_off = page->index << PAGE_CACHE_SHIFT;
430 int len = PAGE_CACHE_SIZE;
431 loff_t i_size;
432 int err = 0;
433 struct ceph_snap_context *snapc, *oldest;
434 u64 snap_size = 0;
435 long writeback_stat;
436
437 dout("writepage %p idx %lu\n", page, page->index);
438
439 if (!page->mapping || !page->mapping->host) {
440 dout("writepage %p - no mapping\n", page);
441 return -EFAULT;
442 }
443 inode = page->mapping->host;
444 ci = ceph_inode(inode);
445 fsc = ceph_inode_to_client(inode);
446 osdc = &fsc->client->osdc;
447
448 /* verify this is a writeable snap context */
449 snapc = page_snap_context(page);
450 if (snapc == NULL) {
451 dout("writepage %p page %p not dirty?\n", inode, page);
452 goto out;
453 }
454 oldest = get_oldest_context(inode, &snap_size);
455 if (snapc->seq > oldest->seq) {
456 dout("writepage %p page %p snapc %p not writeable - noop\n",
457 inode, page, snapc);
458 /* we should only noop if called by kswapd */
459 WARN_ON((current->flags & PF_MEMALLOC) == 0);
460 ceph_put_snap_context(oldest);
461 goto out;
462 }
463 ceph_put_snap_context(oldest);
464
465 /* is this a partial page at end of file? */
466 if (snap_size)
467 i_size = snap_size;
468 else
469 i_size = i_size_read(inode);
470 if (i_size < page_off + len)
471 len = i_size - page_off;
472
473 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
474 inode, page, page->index, page_off, len, snapc);
475
476 writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
477 if (writeback_stat >
478 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
479 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
480
481 set_page_writeback(page);
482 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
483 &ci->i_layout, snapc,
484 page_off, len,
485 ci->i_truncate_seq, ci->i_truncate_size,
486 &inode->i_mtime,
487 &page, 1, 0, 0, true);
488 if (err < 0) {
489 dout("writepage setting page/mapping error %d %p\n", err, page);
490 SetPageError(page);
491 mapping_set_error(&inode->i_data, err);
492 if (wbc)
493 wbc->pages_skipped++;
494 } else {
495 dout("writepage cleaned page %p\n", page);
496 err = 0; /* vfs expects us to return 0 */
497 }
498 page->private = 0;
499 ClearPagePrivate(page);
500 end_page_writeback(page);
501 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
502 ceph_put_snap_context(snapc); /* page's reference */
503out:
504 return err;
505}
506
507static int ceph_writepage(struct page *page, struct writeback_control *wbc)
508{
509 int err;
510 struct inode *inode = page->mapping->host;
511 BUG_ON(!inode);
512 ihold(inode);
513 err = writepage_nounlock(page, wbc);
514 unlock_page(page);
515 iput(inode);
516 return err;
517}
518
519
520/*
521 * lame release_pages helper. release_pages() isn't exported to
522 * modules.
523 */
524static void ceph_release_pages(struct page **pages, int num)
525{
526 struct pagevec pvec;
527 int i;
528
529 pagevec_init(&pvec, 0);
530 for (i = 0; i < num; i++) {
531 if (pagevec_add(&pvec, pages[i]) == 0)
532 pagevec_release(&pvec);
533 }
534 pagevec_release(&pvec);
535}
536
537
538/*
539 * async writeback completion handler.
540 *
541 * If we get an error, set the mapping error bit, but not the individual
542 * page error bits.
543 */
544static void writepages_finish(struct ceph_osd_request *req,
545 struct ceph_msg *msg)
546{
547 struct inode *inode = req->r_inode;
548 struct ceph_osd_reply_head *replyhead;
549 struct ceph_osd_op *op;
550 struct ceph_inode_info *ci = ceph_inode(inode);
551 unsigned wrote;
552 struct page *page;
553 int i;
554 struct ceph_snap_context *snapc = req->r_snapc;
555 struct address_space *mapping = inode->i_mapping;
556 __s32 rc = -EIO;
557 u64 bytes = 0;
558 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
559 long writeback_stat;
560 unsigned issued = ceph_caps_issued(ci);
561
562 /* parse reply */
563 replyhead = msg->front.iov_base;
564 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
565 op = (void *)(replyhead + 1);
566 rc = le32_to_cpu(replyhead->result);
567 bytes = le64_to_cpu(op->extent.length);
568
569 if (rc >= 0) {
570 /*
571 * Assume we wrote the pages we originally sent. The
572 * osd might reply with fewer pages if our writeback
573 * raced with a truncation and was adjusted at the osd,
574 * so don't believe the reply.
575 */
576 wrote = req->r_num_pages;
577 } else {
578 wrote = 0;
579 mapping_set_error(mapping, rc);
580 }
581 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
582 inode, rc, bytes, wrote);
583
584 /* clean all pages */
585 for (i = 0; i < req->r_num_pages; i++) {
586 page = req->r_pages[i];
587 BUG_ON(!page);
588 WARN_ON(!PageUptodate(page));
589
590 writeback_stat =
591 atomic_long_dec_return(&fsc->writeback_count);
592 if (writeback_stat <
593 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
594 clear_bdi_congested(&fsc->backing_dev_info,
595 BLK_RW_ASYNC);
596
597 ceph_put_snap_context(page_snap_context(page));
598 page->private = 0;
599 ClearPagePrivate(page);
600 dout("unlocking %d %p\n", i, page);
601 end_page_writeback(page);
602
603 /*
604 * We lost the cache cap, need to truncate the page before
605 * it is unlocked, otherwise we'd truncate it later in the
606 * page truncation thread, possibly losing some data that
607 * raced its way in
608 */
609 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
610 generic_error_remove_page(inode->i_mapping, page);
611
612 unlock_page(page);
613 }
614 dout("%p wrote+cleaned %d pages\n", inode, wrote);
615 ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
616
617 ceph_release_pages(req->r_pages, req->r_num_pages);
618 if (req->r_pages_from_pool)
619 mempool_free(req->r_pages,
620 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
621 else
622 kfree(req->r_pages);
623 ceph_osdc_put_request(req);
624}
625
626/*
627 * allocate a page vec, either directly, or if necessary, via a the
628 * mempool. we avoid the mempool if we can because req->r_num_pages
629 * may be less than the maximum write size.
630 */
631static void alloc_page_vec(struct ceph_fs_client *fsc,
632 struct ceph_osd_request *req)
633{
634 req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
635 GFP_NOFS);
636 if (!req->r_pages) {
637 req->r_pages = mempool_alloc(fsc->wb_pagevec_pool, GFP_NOFS);
638 req->r_pages_from_pool = 1;
639 WARN_ON(!req->r_pages);
640 }
641}
642
643/*
644 * initiate async writeback
645 */
646static int ceph_writepages_start(struct address_space *mapping,
647 struct writeback_control *wbc)
648{
649 struct inode *inode = mapping->host;
650 struct ceph_inode_info *ci = ceph_inode(inode);
651 struct ceph_fs_client *fsc;
652 pgoff_t index, start, end;
653 int range_whole = 0;
654 int should_loop = 1;
655 pgoff_t max_pages = 0, max_pages_ever = 0;
656 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
657 struct pagevec pvec;
658 int done = 0;
659 int rc = 0;
660 unsigned wsize = 1 << inode->i_blkbits;
661 struct ceph_osd_request *req = NULL;
662 int do_sync;
663 u64 snap_size = 0;
664
665 /*
666 * Include a 'sync' in the OSD request if this is a data
667 * integrity write (e.g., O_SYNC write or fsync()), or if our
668 * cap is being revoked.
669 */
670 do_sync = wbc->sync_mode == WB_SYNC_ALL;
671 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
672 do_sync = 1;
673 dout("writepages_start %p dosync=%d (mode=%s)\n",
674 inode, do_sync,
675 wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
676 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
677
678 fsc = ceph_inode_to_client(inode);
679 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
680 pr_warning("writepage_start %p on forced umount\n", inode);
681 return -EIO; /* we're in a forced umount, don't write! */
682 }
683 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
684 wsize = fsc->mount_options->wsize;
685 if (wsize < PAGE_CACHE_SIZE)
686 wsize = PAGE_CACHE_SIZE;
687 max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
688
689 pagevec_init(&pvec, 0);
690
691 /* where to start/end? */
692 if (wbc->range_cyclic) {
693 start = mapping->writeback_index; /* Start from prev offset */
694 end = -1;
695 dout(" cyclic, start at %lu\n", start);
696 } else {
697 start = wbc->range_start >> PAGE_CACHE_SHIFT;
698 end = wbc->range_end >> PAGE_CACHE_SHIFT;
699 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
700 range_whole = 1;
701 should_loop = 0;
702 dout(" not cyclic, %lu to %lu\n", start, end);
703 }
704 index = start;
705
706retry:
707 /* find oldest snap context with dirty data */
708 ceph_put_snap_context(snapc);
709 snapc = get_oldest_context(inode, &snap_size);
710 if (!snapc) {
711 /* hmm, why does writepages get called when there
712 is no dirty data? */
713 dout(" no snap context with dirty data?\n");
714 goto out;
715 }
716 dout(" oldest snapc is %p seq %lld (%d snaps)\n",
717 snapc, snapc->seq, snapc->num_snaps);
718 if (last_snapc && snapc != last_snapc) {
719 /* if we switched to a newer snapc, restart our scan at the
720 * start of the original file range. */
721 dout(" snapc differs from last pass, restarting at %lu\n",
722 index);
723 index = start;
724 }
725 last_snapc = snapc;
726
727 while (!done && index <= end) {
728 unsigned i;
729 int first;
730 pgoff_t next;
731 int pvec_pages, locked_pages;
732 struct page *page;
733 int want;
734 u64 offset, len;
735 struct ceph_osd_request_head *reqhead;
736 struct ceph_osd_op *op;
737 long writeback_stat;
738
739 next = 0;
740 locked_pages = 0;
741 max_pages = max_pages_ever;
742
743get_more_pages:
744 first = -1;
745 want = min(end - index,
746 min((pgoff_t)PAGEVEC_SIZE,
747 max_pages - (pgoff_t)locked_pages) - 1)
748 + 1;
749 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
750 PAGECACHE_TAG_DIRTY,
751 want);
752 dout("pagevec_lookup_tag got %d\n", pvec_pages);
753 if (!pvec_pages && !locked_pages)
754 break;
755 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
756 page = pvec.pages[i];
757 dout("? %p idx %lu\n", page, page->index);
758 if (locked_pages == 0)
759 lock_page(page); /* first page */
760 else if (!trylock_page(page))
761 break;
762
763 /* only dirty pages, or our accounting breaks */
764 if (unlikely(!PageDirty(page)) ||
765 unlikely(page->mapping != mapping)) {
766 dout("!dirty or !mapping %p\n", page);
767 unlock_page(page);
768 break;
769 }
770 if (!wbc->range_cyclic && page->index > end) {
771 dout("end of range %p\n", page);
772 done = 1;
773 unlock_page(page);
774 break;
775 }
776 if (next && (page->index != next)) {
777 dout("not consecutive %p\n", page);
778 unlock_page(page);
779 break;
780 }
781 if (wbc->sync_mode != WB_SYNC_NONE) {
782 dout("waiting on writeback %p\n", page);
783 wait_on_page_writeback(page);
784 }
785 if ((snap_size && page_offset(page) > snap_size) ||
786 (!snap_size &&
787 page_offset(page) > i_size_read(inode))) {
788 dout("%p page eof %llu\n", page, snap_size ?
789 snap_size : i_size_read(inode));
790 done = 1;
791 unlock_page(page);
792 break;
793 }
794 if (PageWriteback(page)) {
795 dout("%p under writeback\n", page);
796 unlock_page(page);
797 break;
798 }
799
800 /* only if matching snap context */
801 pgsnapc = page_snap_context(page);
802 if (pgsnapc->seq > snapc->seq) {
803 dout("page snapc %p %lld > oldest %p %lld\n",
804 pgsnapc, pgsnapc->seq, snapc, snapc->seq);
805 unlock_page(page);
806 if (!locked_pages)
807 continue; /* keep looking for snap */
808 break;
809 }
810
811 if (!clear_page_dirty_for_io(page)) {
812 dout("%p !clear_page_dirty_for_io\n", page);
813 unlock_page(page);
814 break;
815 }
816
817 /* ok */
818 if (locked_pages == 0) {
819 /* prepare async write request */
820 offset = (unsigned long long)page->index
821 << PAGE_CACHE_SHIFT;
822 len = wsize;
823 req = ceph_osdc_new_request(&fsc->client->osdc,
824 &ci->i_layout,
825 ceph_vino(inode),
826 offset, &len,
827 CEPH_OSD_OP_WRITE,
828 CEPH_OSD_FLAG_WRITE |
829 CEPH_OSD_FLAG_ONDISK,
830 snapc, do_sync,
831 ci->i_truncate_seq,
832 ci->i_truncate_size,
833 &inode->i_mtime, true, 1, 0);
834
835 if (!req) {
836 rc = -ENOMEM;
837 unlock_page(page);
838 break;
839 }
840
841 max_pages = req->r_num_pages;
842
843 alloc_page_vec(fsc, req);
844 req->r_callback = writepages_finish;
845 req->r_inode = inode;
846 }
847
848 /* note position of first page in pvec */
849 if (first < 0)
850 first = i;
851 dout("%p will write page %p idx %lu\n",
852 inode, page, page->index);
853
854 writeback_stat =
855 atomic_long_inc_return(&fsc->writeback_count);
856 if (writeback_stat > CONGESTION_ON_THRESH(
857 fsc->mount_options->congestion_kb)) {
858 set_bdi_congested(&fsc->backing_dev_info,
859 BLK_RW_ASYNC);
860 }
861
862 set_page_writeback(page);
863 req->r_pages[locked_pages] = page;
864 locked_pages++;
865 next = page->index + 1;
866 }
867
868 /* did we get anything? */
869 if (!locked_pages)
870 goto release_pvec_pages;
871 if (i) {
872 int j;
873 BUG_ON(!locked_pages || first < 0);
874
875 if (pvec_pages && i == pvec_pages &&
876 locked_pages < max_pages) {
877 dout("reached end pvec, trying for more\n");
878 pagevec_reinit(&pvec);
879 goto get_more_pages;
880 }
881
882 /* shift unused pages over in the pvec... we
883 * will need to release them below. */
884 for (j = i; j < pvec_pages; j++) {
885 dout(" pvec leftover page %p\n",
886 pvec.pages[j]);
887 pvec.pages[j-i+first] = pvec.pages[j];
888 }
889 pvec.nr -= i-first;
890 }
891
892 /* submit the write */
893 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
894 len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
895 (u64)locked_pages << PAGE_CACHE_SHIFT);
896 dout("writepages got %d pages at %llu~%llu\n",
897 locked_pages, offset, len);
898
899 /* revise final length, page count */
900 req->r_num_pages = locked_pages;
901 reqhead = req->r_request->front.iov_base;
902 op = (void *)(reqhead + 1);
903 op->extent.length = cpu_to_le64(len);
904 op->payload_len = cpu_to_le32(len);
905 req->r_request->hdr.data_len = cpu_to_le32(len);
906
907 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
908 BUG_ON(rc);
909 req = NULL;
910
911 /* continue? */
912 index = next;
913 wbc->nr_to_write -= locked_pages;
914 if (wbc->nr_to_write <= 0)
915 done = 1;
916
917release_pvec_pages:
918 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
919 pvec.nr ? pvec.pages[0] : NULL);
920 pagevec_release(&pvec);
921
922 if (locked_pages && !done)
923 goto retry;
924 }
925
926 if (should_loop && !done) {
927 /* more to do; loop back to beginning of file */
928 dout("writepages looping back to beginning of file\n");
929 should_loop = 0;
930 index = 0;
931 goto retry;
932 }
933
934 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
935 mapping->writeback_index = index;
936
937out:
938 if (req)
939 ceph_osdc_put_request(req);
940 ceph_put_snap_context(snapc);
941 dout("writepages done, rc = %d\n", rc);
942 return rc;
943}
944
945
946
947/*
948 * See if a given @snapc is either writeable, or already written.
949 */
950static int context_is_writeable_or_written(struct inode *inode,
951 struct ceph_snap_context *snapc)
952{
953 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
954 int ret = !oldest || snapc->seq <= oldest->seq;
955
956 ceph_put_snap_context(oldest);
957 return ret;
958}
959
960/*
961 * We are only allowed to write into/dirty the page if the page is
962 * clean, or already dirty within the same snap context.
963 *
964 * called with page locked.
965 * return success with page locked,
966 * or any failure (incl -EAGAIN) with page unlocked.
967 */
968static int ceph_update_writeable_page(struct file *file,
969 loff_t pos, unsigned len,
970 struct page *page)
971{
972 struct inode *inode = file->f_dentry->d_inode;
973 struct ceph_inode_info *ci = ceph_inode(inode);
974 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
975 loff_t page_off = pos & PAGE_CACHE_MASK;
976 int pos_in_page = pos & ~PAGE_CACHE_MASK;
977 int end_in_page = pos_in_page + len;
978 loff_t i_size;
979 int r;
980 struct ceph_snap_context *snapc, *oldest;
981
982retry_locked:
983 /* writepages currently holds page lock, but if we change that later, */
984 wait_on_page_writeback(page);
985
986 /* check snap context */
987 BUG_ON(!ci->i_snap_realm);
988 down_read(&mdsc->snap_rwsem);
989 BUG_ON(!ci->i_snap_realm->cached_context);
990 snapc = page_snap_context(page);
991 if (snapc && snapc != ci->i_head_snapc) {
992 /*
993 * this page is already dirty in another (older) snap
994 * context! is it writeable now?
995 */
996 oldest = get_oldest_context(inode, NULL);
997 up_read(&mdsc->snap_rwsem);
998
999 if (snapc->seq > oldest->seq) {
1000 ceph_put_snap_context(oldest);
1001 dout(" page %p snapc %p not current or oldest\n",
1002 page, snapc);
1003 /*
1004 * queue for writeback, and wait for snapc to
1005 * be writeable or written
1006 */
1007 snapc = ceph_get_snap_context(snapc);
1008 unlock_page(page);
1009 ceph_queue_writeback(inode);
1010 r = wait_event_interruptible(ci->i_cap_wq,
1011 context_is_writeable_or_written(inode, snapc));
1012 ceph_put_snap_context(snapc);
1013 if (r == -ERESTARTSYS)
1014 return r;
1015 return -EAGAIN;
1016 }
1017 ceph_put_snap_context(oldest);
1018
1019 /* yay, writeable, do it now (without dropping page lock) */
1020 dout(" page %p snapc %p not current, but oldest\n",
1021 page, snapc);
1022 if (!clear_page_dirty_for_io(page))
1023 goto retry_locked;
1024 r = writepage_nounlock(page, NULL);
1025 if (r < 0)
1026 goto fail_nosnap;
1027 goto retry_locked;
1028 }
1029
1030 if (PageUptodate(page)) {
1031 dout(" page %p already uptodate\n", page);
1032 return 0;
1033 }
1034
1035 /* full page? */
1036 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
1037 return 0;
1038
1039 /* past end of file? */
1040 i_size = inode->i_size; /* caller holds i_mutex */
1041
1042 if (i_size + len > inode->i_sb->s_maxbytes) {
1043 /* file is too big */
1044 r = -EINVAL;
1045 goto fail;
1046 }
1047
1048 if (page_off >= i_size ||
1049 (pos_in_page == 0 && (pos+len) >= i_size &&
1050 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1051 dout(" zeroing %p 0 - %d and %d - %d\n",
1052 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1053 zero_user_segments(page,
1054 0, pos_in_page,
1055 end_in_page, PAGE_CACHE_SIZE);
1056 return 0;
1057 }
1058
1059 /* we need to read it. */
1060 up_read(&mdsc->snap_rwsem);
1061 r = readpage_nounlock(file, page);
1062 if (r < 0)
1063 goto fail_nosnap;
1064 goto retry_locked;
1065
1066fail:
1067 up_read(&mdsc->snap_rwsem);
1068fail_nosnap:
1069 unlock_page(page);
1070 return r;
1071}
1072
1073/*
1074 * We are only allowed to write into/dirty the page if the page is
1075 * clean, or already dirty within the same snap context.
1076 */
1077static int ceph_write_begin(struct file *file, struct address_space *mapping,
1078 loff_t pos, unsigned len, unsigned flags,
1079 struct page **pagep, void **fsdata)
1080{
1081 struct inode *inode = file->f_dentry->d_inode;
1082 struct page *page;
1083 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1084 int r;
1085
1086 do {
1087 /* get a page */
1088 page = grab_cache_page_write_begin(mapping, index, 0);
1089 if (!page)
1090 return -ENOMEM;
1091 *pagep = page;
1092
1093 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1094 inode, page, (int)pos, (int)len);
1095
1096 r = ceph_update_writeable_page(file, pos, len, page);
1097 } while (r == -EAGAIN);
1098
1099 return r;
1100}
1101
1102/*
1103 * we don't do anything in here that simple_write_end doesn't do
1104 * except adjust dirty page accounting and drop read lock on
1105 * mdsc->snap_rwsem.
1106 */
1107static int ceph_write_end(struct file *file, struct address_space *mapping,
1108 loff_t pos, unsigned len, unsigned copied,
1109 struct page *page, void *fsdata)
1110{
1111 struct inode *inode = file->f_dentry->d_inode;
1112 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1113 struct ceph_mds_client *mdsc = fsc->mdsc;
1114 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1115 int check_cap = 0;
1116
1117 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1118 inode, page, (int)pos, (int)copied, (int)len);
1119
1120 /* zero the stale part of the page if we did a short copy */
1121 if (copied < len)
1122 zero_user_segment(page, from+copied, len);
1123
1124 /* did file size increase? */
1125 /* (no need for i_size_read(); we caller holds i_mutex */
1126 if (pos+copied > inode->i_size)
1127 check_cap = ceph_inode_set_size(inode, pos+copied);
1128
1129 if (!PageUptodate(page))
1130 SetPageUptodate(page);
1131
1132 set_page_dirty(page);
1133
1134 unlock_page(page);
1135 up_read(&mdsc->snap_rwsem);
1136 page_cache_release(page);
1137
1138 if (check_cap)
1139 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1140
1141 return copied;
1142}
1143
1144/*
1145 * we set .direct_IO to indicate direct io is supported, but since we
1146 * intercept O_DIRECT reads and writes early, this function should
1147 * never get called.
1148 */
1149static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1150 const struct iovec *iov,
1151 loff_t pos, unsigned long nr_segs)
1152{
1153 WARN_ON(1);
1154 return -EINVAL;
1155}
1156
1157const struct address_space_operations ceph_aops = {
1158 .readpage = ceph_readpage,
1159 .readpages = ceph_readpages,
1160 .writepage = ceph_writepage,
1161 .writepages = ceph_writepages_start,
1162 .write_begin = ceph_write_begin,
1163 .write_end = ceph_write_end,
1164 .set_page_dirty = ceph_set_page_dirty,
1165 .invalidatepage = ceph_invalidatepage,
1166 .releasepage = ceph_releasepage,
1167 .direct_IO = ceph_direct_io,
1168};
1169
1170
1171/*
1172 * vm ops
1173 */
1174
1175/*
1176 * Reuse write_begin here for simplicity.
1177 */
1178static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1179{
1180 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1181 struct page *page = vmf->page;
1182 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1183 loff_t off = page->index << PAGE_CACHE_SHIFT;
1184 loff_t size, len;
1185 int ret;
1186
1187 size = i_size_read(inode);
1188 if (off + PAGE_CACHE_SIZE <= size)
1189 len = PAGE_CACHE_SIZE;
1190 else
1191 len = size & ~PAGE_CACHE_MASK;
1192
1193 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1194 off, len, page, page->index);
1195
1196 lock_page(page);
1197
1198 ret = VM_FAULT_NOPAGE;
1199 if ((off > size) ||
1200 (page->mapping != inode->i_mapping))
1201 goto out;
1202
1203 ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1204 if (ret == 0) {
1205 /* success. we'll keep the page locked. */
1206 set_page_dirty(page);
1207 up_read(&mdsc->snap_rwsem);
1208 ret = VM_FAULT_LOCKED;
1209 } else {
1210 if (ret == -ENOMEM)
1211 ret = VM_FAULT_OOM;
1212 else
1213 ret = VM_FAULT_SIGBUS;
1214 }
1215out:
1216 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1217 if (ret != VM_FAULT_LOCKED)
1218 unlock_page(page);
1219 return ret;
1220}
1221
1222static struct vm_operations_struct ceph_vmops = {
1223 .fault = filemap_fault,
1224 .page_mkwrite = ceph_page_mkwrite,
1225};
1226
1227int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1228{
1229 struct address_space *mapping = file->f_mapping;
1230
1231 if (!mapping->a_ops->readpage)
1232 return -ENOEXEC;
1233 file_accessed(file);
1234 vma->vm_ops = &ceph_vmops;
1235 vma->vm_flags |= VM_CAN_NONLINEAR;
1236 return 0;
1237}