1 #include <linux/ceph/ceph_debug.h>
3 #include <linux/backing-dev.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>
13 #include "mds_client.h"
14 #include <linux/ceph/osd_client.h>
17 * Ceph address space ops.
19 * There are a few funny things going on here.
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.
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.
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.
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
48 * Invalidate and so forth must take care to ensure the dirty page
49 * accounting is preserved.
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))
57 static inline struct ceph_snap_context *page_snap_context(struct page *page)
59 if (PagePrivate(page))
60 return (void *)page->private;
65 * Dirty a page. Optimistically adjust accounting, on the assumption
66 * that we won't race with invalidate. If we do, readjust.
68 static int ceph_set_page_dirty(struct page *page)
70 struct address_space *mapping = page->mapping;
72 struct ceph_inode_info *ci;
74 struct ceph_snap_context *snapc;
76 if (unlikely(!mapping))
77 return !TestSetPageDirty(page);
79 if (TestSetPageDirty(page)) {
80 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
81 mapping->host, page, page->index);
85 inode = mapping->host;
86 ci = ceph_inode(inode);
89 * Note that we're grabbing a snapc ref here without holding
92 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
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)
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);
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);
119 * Reference snap context in page->private. Also set
120 * PagePrivate so that we get invalidatepage callback.
122 page->private = (unsigned long)snapc;
123 SetPagePrivate(page);
125 dout("ANON set_page_dirty %p (raced truncate?)\n", page);
129 spin_unlock_irq(&mapping->tree_lock);
132 /* whoops, we failed to dirty the page */
133 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
135 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
137 BUG_ON(!PageDirty(page));
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
146 static void ceph_invalidatepage(struct page *page, unsigned long offset)
149 struct ceph_inode_info *ci;
150 struct ceph_snap_context *snapc = page_snap_context(page);
152 BUG_ON(!PageLocked(page));
153 BUG_ON(!PagePrivate(page));
154 BUG_ON(!page->mapping);
156 inode = page->mapping->host;
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.
163 if (!PageDirty(page))
164 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
167 ClearPageChecked(page);
169 ci = ceph_inode(inode);
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);
176 ClearPagePrivate(page);
178 dout("%p invalidatepage %p idx %lu partial dirty page\n",
179 inode, page, page->index);
183 /* just a sanity check */
184 static int ceph_releasepage(struct page *page, gfp_t g)
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));
194 * read a single page, without unlocking it.
196 static int readpage_nounlock(struct file *filp, struct page *page)
198 struct inode *inode = file_inode(filp);
199 struct ceph_inode_info *ci = ceph_inode(inode);
200 struct ceph_osd_client *osdc =
201 &ceph_inode_to_client(inode)->client->osdc;
203 u64 len = PAGE_CACHE_SIZE;
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 (u64) page_offset(page), &len,
209 ci->i_truncate_seq, ci->i_truncate_size,
216 } else if (err < PAGE_CACHE_SIZE) {
217 /* zero fill remainder of page */
218 zero_user_segment(page, err, PAGE_CACHE_SIZE);
220 SetPageUptodate(page);
223 return err < 0 ? err : 0;
226 static int ceph_readpage(struct file *filp, struct page *page)
228 int r = readpage_nounlock(filp, page);
234 * Finish an async read(ahead) op.
236 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
238 struct inode *inode = req->r_inode;
239 struct ceph_osd_data *osd_data;
240 int rc = req->r_result;
241 int bytes = le32_to_cpu(msg->hdr.data_len);
245 dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
247 /* unlock all pages, zeroing any data we didn't read */
248 osd_data = osd_req_op_extent_osd_data(req, 0);
249 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
250 num_pages = calc_pages_for((u64)osd_data->alignment,
251 (u64)osd_data->length);
252 for (i = 0; i < num_pages; i++) {
253 struct page *page = osd_data->pages[i];
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);
260 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
262 flush_dcache_page(page);
263 SetPageUptodate(page);
265 page_cache_release(page);
266 bytes -= PAGE_CACHE_SIZE;
268 kfree(osd_data->pages);
271 static void ceph_unlock_page_vector(struct page **pages, int num_pages)
275 for (i = 0; i < num_pages; i++)
276 unlock_page(pages[i]);
280 * start an async read(ahead) operation. return nr_pages we submitted
281 * a read for on success, or negative error code.
283 static int start_read(struct inode *inode, struct list_head *page_list, int max)
285 struct ceph_osd_client *osdc =
286 &ceph_inode_to_client(inode)->client->osdc;
287 struct ceph_inode_info *ci = ceph_inode(inode);
288 struct page *page = list_entry(page_list->prev, struct page, lru);
289 struct ceph_vino vino;
290 struct ceph_osd_request *req;
299 off = (u64) page_offset(page);
302 next_index = page->index;
303 list_for_each_entry_reverse(page, page_list, lru) {
304 if (page->index != next_index)
308 if (max && nr_pages == max)
311 len = nr_pages << PAGE_CACHE_SHIFT;
312 dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
314 vino = ceph_vino(inode);
315 req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
317 CEPH_OSD_FLAG_READ, NULL,
318 ci->i_truncate_seq, ci->i_truncate_size,
323 /* build page vector */
324 nr_pages = calc_pages_for(0, len);
325 pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
329 for (i = 0; i < nr_pages; ++i) {
330 page = list_entry(page_list->prev, struct page, lru);
331 BUG_ON(PageLocked(page));
332 list_del(&page->lru);
334 dout("start_read %p adding %p idx %lu\n", inode, page,
336 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
338 page_cache_release(page);
339 dout("start_read %p add_to_page_cache failed %p\n",
346 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
347 req->r_callback = finish_read;
348 req->r_inode = inode;
350 ceph_osdc_build_request(req, off, NULL, vino.snap, NULL);
352 dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
353 ret = ceph_osdc_start_request(osdc, req, false);
356 ceph_osdc_put_request(req);
360 ceph_unlock_page_vector(pages, nr_pages);
361 ceph_release_page_vector(pages, nr_pages);
363 ceph_osdc_put_request(req);
369 * Read multiple pages. Leave pages we don't read + unlock in page_list;
370 * the caller (VM) cleans them up.
372 static int ceph_readpages(struct file *file, struct address_space *mapping,
373 struct list_head *page_list, unsigned nr_pages)
375 struct inode *inode = file_inode(file);
376 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
380 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
381 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
384 dout("readpages %p file %p nr_pages %d max %d\n", inode,
387 while (!list_empty(page_list)) {
388 rc = start_read(inode, page_list, max);
394 dout("readpages %p file %p ret %d\n", inode, file, rc);
399 * Get ref for the oldest snapc for an inode with dirty data... that is, the
400 * only snap context we are allowed to write back.
402 static struct ceph_snap_context *get_oldest_context(struct inode *inode,
405 struct ceph_inode_info *ci = ceph_inode(inode);
406 struct ceph_snap_context *snapc = NULL;
407 struct ceph_cap_snap *capsnap = NULL;
409 spin_lock(&ci->i_ceph_lock);
410 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
411 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
412 capsnap->context, capsnap->dirty_pages);
413 if (capsnap->dirty_pages) {
414 snapc = ceph_get_snap_context(capsnap->context);
416 *snap_size = capsnap->size;
420 if (!snapc && ci->i_wrbuffer_ref_head) {
421 snapc = ceph_get_snap_context(ci->i_head_snapc);
422 dout(" head snapc %p has %d dirty pages\n",
423 snapc, ci->i_wrbuffer_ref_head);
425 spin_unlock(&ci->i_ceph_lock);
430 * Write a single page, but leave the page locked.
432 * If we get a write error, set the page error bit, but still adjust the
433 * dirty page accounting (i.e., page is no longer dirty).
435 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
438 struct ceph_inode_info *ci;
439 struct ceph_fs_client *fsc;
440 struct ceph_osd_client *osdc;
441 loff_t page_off = page_offset(page);
442 int len = PAGE_CACHE_SIZE;
445 struct ceph_snap_context *snapc, *oldest;
449 dout("writepage %p idx %lu\n", page, page->index);
451 if (!page->mapping || !page->mapping->host) {
452 dout("writepage %p - no mapping\n", page);
455 inode = page->mapping->host;
456 ci = ceph_inode(inode);
457 fsc = ceph_inode_to_client(inode);
458 osdc = &fsc->client->osdc;
460 /* verify this is a writeable snap context */
461 snapc = page_snap_context(page);
463 dout("writepage %p page %p not dirty?\n", inode, page);
466 oldest = get_oldest_context(inode, &snap_size);
467 if (snapc->seq > oldest->seq) {
468 dout("writepage %p page %p snapc %p not writeable - noop\n",
470 /* we should only noop if called by kswapd */
471 WARN_ON((current->flags & PF_MEMALLOC) == 0);
472 ceph_put_snap_context(oldest);
475 ceph_put_snap_context(oldest);
477 /* is this a partial page at end of file? */
481 i_size = i_size_read(inode);
482 if (i_size < page_off + len)
483 len = i_size - page_off;
485 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
486 inode, page, page->index, page_off, len, snapc);
488 writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
490 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
491 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
493 set_page_writeback(page);
494 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
495 &ci->i_layout, snapc,
497 ci->i_truncate_seq, ci->i_truncate_size,
498 &inode->i_mtime, &page, 1);
500 dout("writepage setting page/mapping error %d %p\n", err, page);
502 mapping_set_error(&inode->i_data, err);
504 wbc->pages_skipped++;
506 dout("writepage cleaned page %p\n", page);
507 err = 0; /* vfs expects us to return 0 */
510 ClearPagePrivate(page);
511 end_page_writeback(page);
512 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
513 ceph_put_snap_context(snapc); /* page's reference */
518 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
521 struct inode *inode = page->mapping->host;
524 err = writepage_nounlock(page, wbc);
532 * lame release_pages helper. release_pages() isn't exported to
535 static void ceph_release_pages(struct page **pages, int num)
540 pagevec_init(&pvec, 0);
541 for (i = 0; i < num; i++) {
542 if (pagevec_add(&pvec, pages[i]) == 0)
543 pagevec_release(&pvec);
545 pagevec_release(&pvec);
550 * async writeback completion handler.
552 * If we get an error, set the mapping error bit, but not the individual
555 static void writepages_finish(struct ceph_osd_request *req,
556 struct ceph_msg *msg)
558 struct inode *inode = req->r_inode;
559 struct ceph_inode_info *ci = ceph_inode(inode);
560 struct ceph_osd_data *osd_data;
565 struct ceph_snap_context *snapc = req->r_snapc;
566 struct address_space *mapping = inode->i_mapping;
567 int rc = req->r_result;
568 u64 bytes = req->r_ops[0].extent.length;
569 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
571 unsigned issued = ceph_caps_issued(ci);
573 osd_data = osd_req_op_extent_osd_data(req, 0);
574 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
575 num_pages = calc_pages_for((u64)osd_data->alignment,
576 (u64)osd_data->length);
579 * Assume we wrote the pages we originally sent. The
580 * osd might reply with fewer pages if our writeback
581 * raced with a truncation and was adjusted at the osd,
582 * so don't believe the reply.
587 mapping_set_error(mapping, rc);
589 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
590 inode, rc, bytes, wrote);
592 /* clean all pages */
593 for (i = 0; i < num_pages; i++) {
594 page = osd_data->pages[i];
596 WARN_ON(!PageUptodate(page));
599 atomic_long_dec_return(&fsc->writeback_count);
601 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
602 clear_bdi_congested(&fsc->backing_dev_info,
605 ceph_put_snap_context(page_snap_context(page));
607 ClearPagePrivate(page);
608 dout("unlocking %d %p\n", i, page);
609 end_page_writeback(page);
612 * We lost the cache cap, need to truncate the page before
613 * it is unlocked, otherwise we'd truncate it later in the
614 * page truncation thread, possibly losing some data that
617 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
618 generic_error_remove_page(inode->i_mapping, page);
622 dout("%p wrote+cleaned %d pages\n", inode, wrote);
623 ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc);
625 ceph_release_pages(osd_data->pages, num_pages);
626 if (osd_data->pages_from_pool)
627 mempool_free(osd_data->pages,
628 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
630 kfree(osd_data->pages);
631 ceph_osdc_put_request(req);
634 static struct ceph_osd_request *
635 ceph_writepages_osd_request(struct inode *inode, u64 offset, u64 *len,
636 struct ceph_snap_context *snapc, int num_ops)
638 struct ceph_fs_client *fsc;
639 struct ceph_inode_info *ci;
640 struct ceph_vino vino;
642 fsc = ceph_inode_to_client(inode);
643 ci = ceph_inode(inode);
644 vino = ceph_vino(inode);
645 /* BUG_ON(vino.snap != CEPH_NOSNAP); */
647 return ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
648 vino, offset, len, num_ops, CEPH_OSD_OP_WRITE,
649 CEPH_OSD_FLAG_WRITE|CEPH_OSD_FLAG_ONDISK,
650 snapc, ci->i_truncate_seq, ci->i_truncate_size, true);
654 * initiate async writeback
656 static int ceph_writepages_start(struct address_space *mapping,
657 struct writeback_control *wbc)
659 struct inode *inode = mapping->host;
660 struct ceph_inode_info *ci = ceph_inode(inode);
661 struct ceph_fs_client *fsc;
662 pgoff_t index, start, end;
665 pgoff_t max_pages = 0, max_pages_ever = 0;
666 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
670 unsigned wsize = 1 << inode->i_blkbits;
671 struct ceph_osd_request *req = NULL;
676 * Include a 'sync' in the OSD request if this is a data
677 * integrity write (e.g., O_SYNC write or fsync()), or if our
678 * cap is being revoked.
680 do_sync = wbc->sync_mode == WB_SYNC_ALL;
681 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
683 dout("writepages_start %p dosync=%d (mode=%s)\n",
685 wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
686 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
688 fsc = ceph_inode_to_client(inode);
689 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
690 pr_warning("writepage_start %p on forced umount\n", inode);
691 return -EIO; /* we're in a forced umount, don't write! */
693 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
694 wsize = fsc->mount_options->wsize;
695 if (wsize < PAGE_CACHE_SIZE)
696 wsize = PAGE_CACHE_SIZE;
697 max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
699 pagevec_init(&pvec, 0);
701 /* where to start/end? */
702 if (wbc->range_cyclic) {
703 start = mapping->writeback_index; /* Start from prev offset */
705 dout(" cyclic, start at %lu\n", start);
707 start = wbc->range_start >> PAGE_CACHE_SHIFT;
708 end = wbc->range_end >> PAGE_CACHE_SHIFT;
709 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
712 dout(" not cyclic, %lu to %lu\n", start, end);
717 /* find oldest snap context with dirty data */
718 ceph_put_snap_context(snapc);
720 snapc = get_oldest_context(inode, &snap_size);
722 /* hmm, why does writepages get called when there
724 dout(" no snap context with dirty data?\n");
728 snap_size = i_size_read(inode);
729 dout(" oldest snapc is %p seq %lld (%d snaps)\n",
730 snapc, snapc->seq, snapc->num_snaps);
731 if (last_snapc && snapc != last_snapc) {
732 /* if we switched to a newer snapc, restart our scan at the
733 * start of the original file range. */
734 dout(" snapc differs from last pass, restarting at %lu\n",
740 while (!done && index <= end) {
741 int num_ops = do_sync ? 2 : 1;
742 struct ceph_vino vino;
746 int pvec_pages, locked_pages;
747 struct page **pages = NULL;
748 mempool_t *pool = NULL; /* Becomes non-null if mempool used */
756 max_pages = max_pages_ever;
760 want = min(end - index,
761 min((pgoff_t)PAGEVEC_SIZE,
762 max_pages - (pgoff_t)locked_pages) - 1)
764 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
767 dout("pagevec_lookup_tag got %d\n", pvec_pages);
768 if (!pvec_pages && !locked_pages)
770 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
771 page = pvec.pages[i];
772 dout("? %p idx %lu\n", page, page->index);
773 if (locked_pages == 0)
774 lock_page(page); /* first page */
775 else if (!trylock_page(page))
778 /* only dirty pages, or our accounting breaks */
779 if (unlikely(!PageDirty(page)) ||
780 unlikely(page->mapping != mapping)) {
781 dout("!dirty or !mapping %p\n", page);
785 if (!wbc->range_cyclic && page->index > end) {
786 dout("end of range %p\n", page);
791 if (next && (page->index != next)) {
792 dout("not consecutive %p\n", page);
796 if (wbc->sync_mode != WB_SYNC_NONE) {
797 dout("waiting on writeback %p\n", page);
798 wait_on_page_writeback(page);
800 if (page_offset(page) >= snap_size) {
801 dout("%p page eof %llu\n", page, snap_size);
806 if (PageWriteback(page)) {
807 dout("%p under writeback\n", page);
812 /* only if matching snap context */
813 pgsnapc = page_snap_context(page);
814 if (pgsnapc->seq > snapc->seq) {
815 dout("page snapc %p %lld > oldest %p %lld\n",
816 pgsnapc, pgsnapc->seq, snapc, snapc->seq);
819 continue; /* keep looking for snap */
823 if (!clear_page_dirty_for_io(page)) {
824 dout("%p !clear_page_dirty_for_io\n", page);
830 * We have something to write. If this is
831 * the first locked page this time through,
832 * allocate an osd request and a page array
835 if (locked_pages == 0) {
840 /* prepare async write request */
841 offset = (u64)page_offset(page);
843 req = ceph_writepages_osd_request(inode,
853 req->r_callback = writepages_finish;
854 req->r_inode = inode;
856 max_pages = calc_pages_for(0, (u64)len);
857 size = max_pages * sizeof (*pages);
858 pages = kmalloc(size, GFP_NOFS);
860 pool = fsc->wb_pagevec_pool;
861 pages = mempool_alloc(pool, GFP_NOFS);
866 /* note position of first page in pvec */
869 dout("%p will write page %p idx %lu\n",
870 inode, page, page->index);
873 atomic_long_inc_return(&fsc->writeback_count);
874 if (writeback_stat > CONGESTION_ON_THRESH(
875 fsc->mount_options->congestion_kb)) {
876 set_bdi_congested(&fsc->backing_dev_info,
880 set_page_writeback(page);
881 pages[locked_pages] = page;
883 next = page->index + 1;
886 /* did we get anything? */
888 goto release_pvec_pages;
891 BUG_ON(!locked_pages || first < 0);
893 if (pvec_pages && i == pvec_pages &&
894 locked_pages < max_pages) {
895 dout("reached end pvec, trying for more\n");
896 pagevec_reinit(&pvec);
900 /* shift unused pages over in the pvec... we
901 * will need to release them below. */
902 for (j = i; j < pvec_pages; j++) {
903 dout(" pvec leftover page %p\n",
905 pvec.pages[j-i+first] = pvec.pages[j];
910 /* Format the osd request message and submit the write */
912 offset = page_offset(pages[0]);
913 len = min(snap_size - offset,
914 (u64)locked_pages << PAGE_CACHE_SHIFT);
915 dout("writepages got %d pages at %llu~%llu\n",
916 locked_pages, offset, len);
918 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
921 pages = NULL; /* request message now owns the pages array */
924 /* Update the write op length in case we changed it */
926 osd_req_op_extent_update(req, 0, len);
928 vino = ceph_vino(inode);
929 ceph_osdc_build_request(req, offset, snapc, vino.snap,
932 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
938 wbc->nr_to_write -= locked_pages;
939 if (wbc->nr_to_write <= 0)
943 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
944 pvec.nr ? pvec.pages[0] : NULL);
945 pagevec_release(&pvec);
947 if (locked_pages && !done)
951 if (should_loop && !done) {
952 /* more to do; loop back to beginning of file */
953 dout("writepages looping back to beginning of file\n");
959 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
960 mapping->writeback_index = index;
964 ceph_osdc_put_request(req);
965 ceph_put_snap_context(snapc);
966 dout("writepages done, rc = %d\n", rc);
973 * See if a given @snapc is either writeable, or already written.
975 static int context_is_writeable_or_written(struct inode *inode,
976 struct ceph_snap_context *snapc)
978 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
979 int ret = !oldest || snapc->seq <= oldest->seq;
981 ceph_put_snap_context(oldest);
986 * We are only allowed to write into/dirty the page if the page is
987 * clean, or already dirty within the same snap context.
989 * called with page locked.
990 * return success with page locked,
991 * or any failure (incl -EAGAIN) with page unlocked.
993 static int ceph_update_writeable_page(struct file *file,
994 loff_t pos, unsigned len,
997 struct inode *inode = file_inode(file);
998 struct ceph_inode_info *ci = ceph_inode(inode);
999 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1000 loff_t page_off = pos & PAGE_CACHE_MASK;
1001 int pos_in_page = pos & ~PAGE_CACHE_MASK;
1002 int end_in_page = pos_in_page + len;
1005 struct ceph_snap_context *snapc, *oldest;
1008 /* writepages currently holds page lock, but if we change that later, */
1009 wait_on_page_writeback(page);
1011 /* check snap context */
1012 BUG_ON(!ci->i_snap_realm);
1013 down_read(&mdsc->snap_rwsem);
1014 BUG_ON(!ci->i_snap_realm->cached_context);
1015 snapc = page_snap_context(page);
1016 if (snapc && snapc != ci->i_head_snapc) {
1018 * this page is already dirty in another (older) snap
1019 * context! is it writeable now?
1021 oldest = get_oldest_context(inode, NULL);
1022 up_read(&mdsc->snap_rwsem);
1024 if (snapc->seq > oldest->seq) {
1025 ceph_put_snap_context(oldest);
1026 dout(" page %p snapc %p not current or oldest\n",
1029 * queue for writeback, and wait for snapc to
1030 * be writeable or written
1032 snapc = ceph_get_snap_context(snapc);
1034 ceph_queue_writeback(inode);
1035 r = wait_event_interruptible(ci->i_cap_wq,
1036 context_is_writeable_or_written(inode, snapc));
1037 ceph_put_snap_context(snapc);
1038 if (r == -ERESTARTSYS)
1042 ceph_put_snap_context(oldest);
1044 /* yay, writeable, do it now (without dropping page lock) */
1045 dout(" page %p snapc %p not current, but oldest\n",
1047 if (!clear_page_dirty_for_io(page))
1049 r = writepage_nounlock(page, NULL);
1055 if (PageUptodate(page)) {
1056 dout(" page %p already uptodate\n", page);
1061 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
1064 /* past end of file? */
1065 i_size = inode->i_size; /* caller holds i_mutex */
1067 if (i_size + len > inode->i_sb->s_maxbytes) {
1068 /* file is too big */
1073 if (page_off >= i_size ||
1074 (pos_in_page == 0 && (pos+len) >= i_size &&
1075 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1076 dout(" zeroing %p 0 - %d and %d - %d\n",
1077 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1078 zero_user_segments(page,
1080 end_in_page, PAGE_CACHE_SIZE);
1084 /* we need to read it. */
1085 up_read(&mdsc->snap_rwsem);
1086 r = readpage_nounlock(file, page);
1092 up_read(&mdsc->snap_rwsem);
1099 * We are only allowed to write into/dirty the page if the page is
1100 * clean, or already dirty within the same snap context.
1102 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1103 loff_t pos, unsigned len, unsigned flags,
1104 struct page **pagep, void **fsdata)
1106 struct inode *inode = file_inode(file);
1108 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1113 page = grab_cache_page_write_begin(mapping, index, 0);
1118 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1119 inode, page, (int)pos, (int)len);
1121 r = ceph_update_writeable_page(file, pos, len, page);
1122 } while (r == -EAGAIN);
1128 * we don't do anything in here that simple_write_end doesn't do
1129 * except adjust dirty page accounting and drop read lock on
1132 static int ceph_write_end(struct file *file, struct address_space *mapping,
1133 loff_t pos, unsigned len, unsigned copied,
1134 struct page *page, void *fsdata)
1136 struct inode *inode = file_inode(file);
1137 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1138 struct ceph_mds_client *mdsc = fsc->mdsc;
1139 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1142 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1143 inode, page, (int)pos, (int)copied, (int)len);
1145 /* zero the stale part of the page if we did a short copy */
1147 zero_user_segment(page, from+copied, len);
1149 /* did file size increase? */
1150 /* (no need for i_size_read(); we caller holds i_mutex */
1151 if (pos+copied > inode->i_size)
1152 check_cap = ceph_inode_set_size(inode, pos+copied);
1154 if (!PageUptodate(page))
1155 SetPageUptodate(page);
1157 set_page_dirty(page);
1160 up_read(&mdsc->snap_rwsem);
1161 page_cache_release(page);
1164 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1170 * we set .direct_IO to indicate direct io is supported, but since we
1171 * intercept O_DIRECT reads and writes early, this function should
1174 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1175 const struct iovec *iov,
1176 loff_t pos, unsigned long nr_segs)
1182 const struct address_space_operations ceph_aops = {
1183 .readpage = ceph_readpage,
1184 .readpages = ceph_readpages,
1185 .writepage = ceph_writepage,
1186 .writepages = ceph_writepages_start,
1187 .write_begin = ceph_write_begin,
1188 .write_end = ceph_write_end,
1189 .set_page_dirty = ceph_set_page_dirty,
1190 .invalidatepage = ceph_invalidatepage,
1191 .releasepage = ceph_releasepage,
1192 .direct_IO = ceph_direct_io,
1201 * Reuse write_begin here for simplicity.
1203 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1205 struct inode *inode = file_inode(vma->vm_file);
1206 struct page *page = vmf->page;
1207 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1208 loff_t off = page_offset(page);
1212 /* Update time before taking page lock */
1213 file_update_time(vma->vm_file);
1215 size = i_size_read(inode);
1216 if (off + PAGE_CACHE_SIZE <= size)
1217 len = PAGE_CACHE_SIZE;
1219 len = size & ~PAGE_CACHE_MASK;
1221 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1222 off, len, page, page->index);
1226 ret = VM_FAULT_NOPAGE;
1228 (page->mapping != inode->i_mapping))
1231 ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1233 /* success. we'll keep the page locked. */
1234 set_page_dirty(page);
1235 up_read(&mdsc->snap_rwsem);
1236 ret = VM_FAULT_LOCKED;
1241 ret = VM_FAULT_SIGBUS;
1244 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1245 if (ret != VM_FAULT_LOCKED)
1250 static struct vm_operations_struct ceph_vmops = {
1251 .fault = filemap_fault,
1252 .page_mkwrite = ceph_page_mkwrite,
1253 .remap_pages = generic_file_remap_pages,
1256 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1258 struct address_space *mapping = file->f_mapping;
1260 if (!mapping->a_ops->readpage)
1262 file_accessed(file);
1263 vma->vm_ops = &ceph_vmops;