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 int offset,
150 struct ceph_inode_info *ci;
151 struct ceph_snap_context *snapc = page_snap_context(page);
153 BUG_ON(!PageLocked(page));
154 BUG_ON(!PagePrivate(page));
155 BUG_ON(!page->mapping);
157 inode = page->mapping->host;
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.
164 if (!PageDirty(page))
165 pr_err("%p invalidatepage %p page not dirty\n", inode, page);
167 if (offset == 0 && length == PAGE_CACHE_SIZE)
168 ClearPageChecked(page);
170 ci = ceph_inode(inode);
171 if (offset == 0 && length == PAGE_CACHE_SIZE) {
172 dout("%p invalidatepage %p idx %lu full dirty page\n",
173 inode, page, page->index);
174 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
175 ceph_put_snap_context(snapc);
177 ClearPagePrivate(page);
179 dout("%p invalidatepage %p idx %lu partial dirty page %u(%u)\n",
180 inode, page, page->index, offset, length);
184 /* just a sanity check */
185 static int ceph_releasepage(struct page *page, gfp_t g)
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(PagePrivate(page));
195 * read a single page, without unlocking it.
197 static int readpage_nounlock(struct file *filp, struct page *page)
199 struct inode *inode = file_inode(filp);
200 struct ceph_inode_info *ci = ceph_inode(inode);
201 struct ceph_osd_client *osdc =
202 &ceph_inode_to_client(inode)->client->osdc;
204 u64 len = PAGE_CACHE_SIZE;
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 (u64) page_offset(page), &len,
210 ci->i_truncate_seq, ci->i_truncate_size,
217 } else if (err < PAGE_CACHE_SIZE) {
218 /* zero fill remainder of page */
219 zero_user_segment(page, err, PAGE_CACHE_SIZE);
221 SetPageUptodate(page);
224 return err < 0 ? err : 0;
227 static int ceph_readpage(struct file *filp, struct page *page)
229 int r = readpage_nounlock(filp, page);
235 * Finish an async read(ahead) op.
237 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
239 struct inode *inode = req->r_inode;
240 struct ceph_osd_data *osd_data;
241 int rc = req->r_result;
242 int bytes = le32_to_cpu(msg->hdr.data_len);
246 dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
248 /* unlock all pages, zeroing any data we didn't read */
249 osd_data = osd_req_op_extent_osd_data(req, 0);
250 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
251 num_pages = calc_pages_for((u64)osd_data->alignment,
252 (u64)osd_data->length);
253 for (i = 0; i < num_pages; i++) {
254 struct page *page = osd_data->pages[i];
256 if (bytes < (int)PAGE_CACHE_SIZE) {
257 /* zero (remainder of) page */
258 int s = bytes < 0 ? 0 : bytes;
259 zero_user_segment(page, s, PAGE_CACHE_SIZE);
261 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
263 flush_dcache_page(page);
264 SetPageUptodate(page);
266 page_cache_release(page);
267 bytes -= PAGE_CACHE_SIZE;
269 kfree(osd_data->pages);
272 static void ceph_unlock_page_vector(struct page **pages, int num_pages)
276 for (i = 0; i < num_pages; i++)
277 unlock_page(pages[i]);
281 * start an async read(ahead) operation. return nr_pages we submitted
282 * a read for on success, or negative error code.
284 static int start_read(struct inode *inode, struct list_head *page_list, int max)
286 struct ceph_osd_client *osdc =
287 &ceph_inode_to_client(inode)->client->osdc;
288 struct ceph_inode_info *ci = ceph_inode(inode);
289 struct page *page = list_entry(page_list->prev, struct page, lru);
290 struct ceph_vino vino;
291 struct ceph_osd_request *req;
300 off = (u64) page_offset(page);
303 next_index = page->index;
304 list_for_each_entry_reverse(page, page_list, lru) {
305 if (page->index != next_index)
309 if (max && nr_pages == max)
312 len = nr_pages << PAGE_CACHE_SHIFT;
313 dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
315 vino = ceph_vino(inode);
316 req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
318 CEPH_OSD_FLAG_READ, NULL,
319 ci->i_truncate_seq, ci->i_truncate_size,
324 /* build page vector */
325 nr_pages = calc_pages_for(0, len);
326 pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
330 for (i = 0; i < nr_pages; ++i) {
331 page = list_entry(page_list->prev, struct page, lru);
332 BUG_ON(PageLocked(page));
333 list_del(&page->lru);
335 dout("start_read %p adding %p idx %lu\n", inode, page,
337 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
339 page_cache_release(page);
340 dout("start_read %p add_to_page_cache failed %p\n",
347 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
348 req->r_callback = finish_read;
349 req->r_inode = inode;
351 ceph_osdc_build_request(req, off, NULL, vino.snap, NULL);
353 dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
354 ret = ceph_osdc_start_request(osdc, req, false);
357 ceph_osdc_put_request(req);
361 ceph_unlock_page_vector(pages, nr_pages);
362 ceph_release_page_vector(pages, nr_pages);
364 ceph_osdc_put_request(req);
370 * Read multiple pages. Leave pages we don't read + unlock in page_list;
371 * the caller (VM) cleans them up.
373 static int ceph_readpages(struct file *file, struct address_space *mapping,
374 struct list_head *page_list, unsigned nr_pages)
376 struct inode *inode = file_inode(file);
377 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
381 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
382 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
385 dout("readpages %p file %p nr_pages %d max %d\n", inode,
388 while (!list_empty(page_list)) {
389 rc = start_read(inode, page_list, max);
395 dout("readpages %p file %p ret %d\n", inode, file, rc);
400 * Get ref for the oldest snapc for an inode with dirty data... that is, the
401 * only snap context we are allowed to write back.
403 static struct ceph_snap_context *get_oldest_context(struct inode *inode,
406 struct ceph_inode_info *ci = ceph_inode(inode);
407 struct ceph_snap_context *snapc = NULL;
408 struct ceph_cap_snap *capsnap = NULL;
410 spin_lock(&ci->i_ceph_lock);
411 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
412 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
413 capsnap->context, capsnap->dirty_pages);
414 if (capsnap->dirty_pages) {
415 snapc = ceph_get_snap_context(capsnap->context);
417 *snap_size = capsnap->size;
421 if (!snapc && ci->i_wrbuffer_ref_head) {
422 snapc = ceph_get_snap_context(ci->i_head_snapc);
423 dout(" head snapc %p has %d dirty pages\n",
424 snapc, ci->i_wrbuffer_ref_head);
426 spin_unlock(&ci->i_ceph_lock);
431 * Write a single page, but leave the page locked.
433 * If we get a write error, set the page error bit, but still adjust the
434 * dirty page accounting (i.e., page is no longer dirty).
436 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
439 struct ceph_inode_info *ci;
440 struct ceph_fs_client *fsc;
441 struct ceph_osd_client *osdc;
442 loff_t page_off = page_offset(page);
443 int len = PAGE_CACHE_SIZE;
446 struct ceph_snap_context *snapc, *oldest;
450 dout("writepage %p idx %lu\n", page, page->index);
452 if (!page->mapping || !page->mapping->host) {
453 dout("writepage %p - no mapping\n", page);
456 inode = page->mapping->host;
457 ci = ceph_inode(inode);
458 fsc = ceph_inode_to_client(inode);
459 osdc = &fsc->client->osdc;
461 /* verify this is a writeable snap context */
462 snapc = page_snap_context(page);
464 dout("writepage %p page %p not dirty?\n", inode, page);
467 oldest = get_oldest_context(inode, &snap_size);
468 if (snapc->seq > oldest->seq) {
469 dout("writepage %p page %p snapc %p not writeable - noop\n",
471 /* we should only noop if called by kswapd */
472 WARN_ON((current->flags & PF_MEMALLOC) == 0);
473 ceph_put_snap_context(oldest);
476 ceph_put_snap_context(oldest);
478 /* is this a partial page at end of file? */
482 i_size = i_size_read(inode);
483 if (i_size < page_off + len)
484 len = i_size - page_off;
486 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
487 inode, page, page->index, page_off, len, snapc);
489 writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
491 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
492 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
494 set_page_writeback(page);
495 err = ceph_osdc_writepages(osdc, ceph_vino(inode),
496 &ci->i_layout, snapc,
498 ci->i_truncate_seq, ci->i_truncate_size,
499 &inode->i_mtime, &page, 1);
501 dout("writepage setting page/mapping error %d %p\n", err, page);
503 mapping_set_error(&inode->i_data, err);
505 wbc->pages_skipped++;
507 dout("writepage cleaned page %p\n", page);
508 err = 0; /* vfs expects us to return 0 */
511 ClearPagePrivate(page);
512 end_page_writeback(page);
513 ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
514 ceph_put_snap_context(snapc); /* page's reference */
519 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
522 struct inode *inode = page->mapping->host;
525 err = writepage_nounlock(page, wbc);
533 * lame release_pages helper. release_pages() isn't exported to
536 static void ceph_release_pages(struct page **pages, int num)
541 pagevec_init(&pvec, 0);
542 for (i = 0; i < num; i++) {
543 if (pagevec_add(&pvec, pages[i]) == 0)
544 pagevec_release(&pvec);
546 pagevec_release(&pvec);
551 * async writeback completion handler.
553 * If we get an error, set the mapping error bit, but not the individual
556 static void writepages_finish(struct ceph_osd_request *req,
557 struct ceph_msg *msg)
559 struct inode *inode = req->r_inode;
560 struct ceph_inode_info *ci = ceph_inode(inode);
561 struct ceph_osd_data *osd_data;
566 struct ceph_snap_context *snapc = req->r_snapc;
567 struct address_space *mapping = inode->i_mapping;
568 int rc = req->r_result;
569 u64 bytes = req->r_ops[0].extent.length;
570 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
572 unsigned issued = ceph_caps_issued(ci);
574 osd_data = osd_req_op_extent_osd_data(req, 0);
575 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
576 num_pages = calc_pages_for((u64)osd_data->alignment,
577 (u64)osd_data->length);
580 * Assume we wrote the pages we originally sent. The
581 * osd might reply with fewer pages if our writeback
582 * raced with a truncation and was adjusted at the osd,
583 * so don't believe the reply.
588 mapping_set_error(mapping, rc);
590 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
591 inode, rc, bytes, wrote);
593 /* clean all pages */
594 for (i = 0; i < num_pages; i++) {
595 page = osd_data->pages[i];
597 WARN_ON(!PageUptodate(page));
600 atomic_long_dec_return(&fsc->writeback_count);
602 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
603 clear_bdi_congested(&fsc->backing_dev_info,
606 ceph_put_snap_context(page_snap_context(page));
608 ClearPagePrivate(page);
609 dout("unlocking %d %p\n", i, page);
610 end_page_writeback(page);
613 * We lost the cache cap, need to truncate the page before
614 * it is unlocked, otherwise we'd truncate it later in the
615 * page truncation thread, possibly losing some data that
618 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
619 generic_error_remove_page(inode->i_mapping, page);
623 dout("%p wrote+cleaned %d pages\n", inode, wrote);
624 ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc);
626 ceph_release_pages(osd_data->pages, num_pages);
627 if (osd_data->pages_from_pool)
628 mempool_free(osd_data->pages,
629 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
631 kfree(osd_data->pages);
632 ceph_osdc_put_request(req);
635 static struct ceph_osd_request *
636 ceph_writepages_osd_request(struct inode *inode, u64 offset, u64 *len,
637 struct ceph_snap_context *snapc, int num_ops)
639 struct ceph_fs_client *fsc;
640 struct ceph_inode_info *ci;
641 struct ceph_vino vino;
643 fsc = ceph_inode_to_client(inode);
644 ci = ceph_inode(inode);
645 vino = ceph_vino(inode);
646 /* BUG_ON(vino.snap != CEPH_NOSNAP); */
648 return ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
649 vino, offset, len, num_ops, CEPH_OSD_OP_WRITE,
650 CEPH_OSD_FLAG_WRITE|CEPH_OSD_FLAG_ONDISK,
651 snapc, ci->i_truncate_seq, ci->i_truncate_size, true);
655 * initiate async writeback
657 static int ceph_writepages_start(struct address_space *mapping,
658 struct writeback_control *wbc)
660 struct inode *inode = mapping->host;
661 struct ceph_inode_info *ci = ceph_inode(inode);
662 struct ceph_fs_client *fsc;
663 pgoff_t index, start, end;
666 pgoff_t max_pages = 0, max_pages_ever = 0;
667 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
671 unsigned wsize = 1 << inode->i_blkbits;
672 struct ceph_osd_request *req = NULL;
677 * Include a 'sync' in the OSD request if this is a data
678 * integrity write (e.g., O_SYNC write or fsync()), or if our
679 * cap is being revoked.
681 do_sync = wbc->sync_mode == WB_SYNC_ALL;
682 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
684 dout("writepages_start %p dosync=%d (mode=%s)\n",
686 wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
687 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
689 fsc = ceph_inode_to_client(inode);
690 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
691 pr_warning("writepage_start %p on forced umount\n", inode);
692 return -EIO; /* we're in a forced umount, don't write! */
694 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
695 wsize = fsc->mount_options->wsize;
696 if (wsize < PAGE_CACHE_SIZE)
697 wsize = PAGE_CACHE_SIZE;
698 max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
700 pagevec_init(&pvec, 0);
702 /* where to start/end? */
703 if (wbc->range_cyclic) {
704 start = mapping->writeback_index; /* Start from prev offset */
706 dout(" cyclic, start at %lu\n", start);
708 start = wbc->range_start >> PAGE_CACHE_SHIFT;
709 end = wbc->range_end >> PAGE_CACHE_SHIFT;
710 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
713 dout(" not cyclic, %lu to %lu\n", start, end);
718 /* find oldest snap context with dirty data */
719 ceph_put_snap_context(snapc);
721 snapc = get_oldest_context(inode, &snap_size);
723 /* hmm, why does writepages get called when there
725 dout(" no snap context with dirty data?\n");
729 snap_size = i_size_read(inode);
730 dout(" oldest snapc is %p seq %lld (%d snaps)\n",
731 snapc, snapc->seq, snapc->num_snaps);
732 if (last_snapc && snapc != last_snapc) {
733 /* if we switched to a newer snapc, restart our scan at the
734 * start of the original file range. */
735 dout(" snapc differs from last pass, restarting at %lu\n",
741 while (!done && index <= end) {
742 int num_ops = do_sync ? 2 : 1;
743 struct ceph_vino vino;
747 int pvec_pages, locked_pages;
748 struct page **pages = NULL;
749 mempool_t *pool = NULL; /* Becomes non-null if mempool used */
757 max_pages = max_pages_ever;
761 want = min(end - index,
762 min((pgoff_t)PAGEVEC_SIZE,
763 max_pages - (pgoff_t)locked_pages) - 1)
765 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
768 dout("pagevec_lookup_tag got %d\n", pvec_pages);
769 if (!pvec_pages && !locked_pages)
771 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
772 page = pvec.pages[i];
773 dout("? %p idx %lu\n", page, page->index);
774 if (locked_pages == 0)
775 lock_page(page); /* first page */
776 else if (!trylock_page(page))
779 /* only dirty pages, or our accounting breaks */
780 if (unlikely(!PageDirty(page)) ||
781 unlikely(page->mapping != mapping)) {
782 dout("!dirty or !mapping %p\n", page);
786 if (!wbc->range_cyclic && page->index > end) {
787 dout("end of range %p\n", page);
792 if (next && (page->index != next)) {
793 dout("not consecutive %p\n", page);
797 if (wbc->sync_mode != WB_SYNC_NONE) {
798 dout("waiting on writeback %p\n", page);
799 wait_on_page_writeback(page);
801 if (page_offset(page) >= snap_size) {
802 dout("%p page eof %llu\n", page, snap_size);
807 if (PageWriteback(page)) {
808 dout("%p under writeback\n", page);
813 /* only if matching snap context */
814 pgsnapc = page_snap_context(page);
815 if (pgsnapc->seq > snapc->seq) {
816 dout("page snapc %p %lld > oldest %p %lld\n",
817 pgsnapc, pgsnapc->seq, snapc, snapc->seq);
820 continue; /* keep looking for snap */
824 if (!clear_page_dirty_for_io(page)) {
825 dout("%p !clear_page_dirty_for_io\n", page);
831 * We have something to write. If this is
832 * the first locked page this time through,
833 * allocate an osd request and a page array
836 if (locked_pages == 0) {
841 /* prepare async write request */
842 offset = (u64)page_offset(page);
844 req = ceph_writepages_osd_request(inode,
854 req->r_callback = writepages_finish;
855 req->r_inode = inode;
857 max_pages = calc_pages_for(0, (u64)len);
858 size = max_pages * sizeof (*pages);
859 pages = kmalloc(size, GFP_NOFS);
861 pool = fsc->wb_pagevec_pool;
862 pages = mempool_alloc(pool, GFP_NOFS);
867 /* note position of first page in pvec */
870 dout("%p will write page %p idx %lu\n",
871 inode, page, page->index);
874 atomic_long_inc_return(&fsc->writeback_count);
875 if (writeback_stat > CONGESTION_ON_THRESH(
876 fsc->mount_options->congestion_kb)) {
877 set_bdi_congested(&fsc->backing_dev_info,
881 set_page_writeback(page);
882 pages[locked_pages] = page;
884 next = page->index + 1;
887 /* did we get anything? */
889 goto release_pvec_pages;
892 BUG_ON(!locked_pages || first < 0);
894 if (pvec_pages && i == pvec_pages &&
895 locked_pages < max_pages) {
896 dout("reached end pvec, trying for more\n");
897 pagevec_reinit(&pvec);
901 /* shift unused pages over in the pvec... we
902 * will need to release them below. */
903 for (j = i; j < pvec_pages; j++) {
904 dout(" pvec leftover page %p\n",
906 pvec.pages[j-i+first] = pvec.pages[j];
911 /* Format the osd request message and submit the write */
913 offset = page_offset(pages[0]);
914 len = min(snap_size - offset,
915 (u64)locked_pages << PAGE_CACHE_SHIFT);
916 dout("writepages got %d pages at %llu~%llu\n",
917 locked_pages, offset, len);
919 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
922 pages = NULL; /* request message now owns the pages array */
925 /* Update the write op length in case we changed it */
927 osd_req_op_extent_update(req, 0, len);
929 vino = ceph_vino(inode);
930 ceph_osdc_build_request(req, offset, snapc, vino.snap,
933 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
939 wbc->nr_to_write -= locked_pages;
940 if (wbc->nr_to_write <= 0)
944 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
945 pvec.nr ? pvec.pages[0] : NULL);
946 pagevec_release(&pvec);
948 if (locked_pages && !done)
952 if (should_loop && !done) {
953 /* more to do; loop back to beginning of file */
954 dout("writepages looping back to beginning of file\n");
960 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
961 mapping->writeback_index = index;
965 ceph_osdc_put_request(req);
966 ceph_put_snap_context(snapc);
967 dout("writepages done, rc = %d\n", rc);
974 * See if a given @snapc is either writeable, or already written.
976 static int context_is_writeable_or_written(struct inode *inode,
977 struct ceph_snap_context *snapc)
979 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
980 int ret = !oldest || snapc->seq <= oldest->seq;
982 ceph_put_snap_context(oldest);
987 * We are only allowed to write into/dirty the page if the page is
988 * clean, or already dirty within the same snap context.
990 * called with page locked.
991 * return success with page locked,
992 * or any failure (incl -EAGAIN) with page unlocked.
994 static int ceph_update_writeable_page(struct file *file,
995 loff_t pos, unsigned len,
998 struct inode *inode = file_inode(file);
999 struct ceph_inode_info *ci = ceph_inode(inode);
1000 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1001 loff_t page_off = pos & PAGE_CACHE_MASK;
1002 int pos_in_page = pos & ~PAGE_CACHE_MASK;
1003 int end_in_page = pos_in_page + len;
1006 struct ceph_snap_context *snapc, *oldest;
1009 /* writepages currently holds page lock, but if we change that later, */
1010 wait_on_page_writeback(page);
1012 /* check snap context */
1013 BUG_ON(!ci->i_snap_realm);
1014 down_read(&mdsc->snap_rwsem);
1015 BUG_ON(!ci->i_snap_realm->cached_context);
1016 snapc = page_snap_context(page);
1017 if (snapc && snapc != ci->i_head_snapc) {
1019 * this page is already dirty in another (older) snap
1020 * context! is it writeable now?
1022 oldest = get_oldest_context(inode, NULL);
1023 up_read(&mdsc->snap_rwsem);
1025 if (snapc->seq > oldest->seq) {
1026 ceph_put_snap_context(oldest);
1027 dout(" page %p snapc %p not current or oldest\n",
1030 * queue for writeback, and wait for snapc to
1031 * be writeable or written
1033 snapc = ceph_get_snap_context(snapc);
1035 ceph_queue_writeback(inode);
1036 r = wait_event_interruptible(ci->i_cap_wq,
1037 context_is_writeable_or_written(inode, snapc));
1038 ceph_put_snap_context(snapc);
1039 if (r == -ERESTARTSYS)
1043 ceph_put_snap_context(oldest);
1045 /* yay, writeable, do it now (without dropping page lock) */
1046 dout(" page %p snapc %p not current, but oldest\n",
1048 if (!clear_page_dirty_for_io(page))
1050 r = writepage_nounlock(page, NULL);
1056 if (PageUptodate(page)) {
1057 dout(" page %p already uptodate\n", page);
1062 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
1065 /* past end of file? */
1066 i_size = inode->i_size; /* caller holds i_mutex */
1068 if (i_size + len > inode->i_sb->s_maxbytes) {
1069 /* file is too big */
1074 if (page_off >= i_size ||
1075 (pos_in_page == 0 && (pos+len) >= i_size &&
1076 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
1077 dout(" zeroing %p 0 - %d and %d - %d\n",
1078 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
1079 zero_user_segments(page,
1081 end_in_page, PAGE_CACHE_SIZE);
1085 /* we need to read it. */
1086 up_read(&mdsc->snap_rwsem);
1087 r = readpage_nounlock(file, page);
1093 up_read(&mdsc->snap_rwsem);
1100 * We are only allowed to write into/dirty the page if the page is
1101 * clean, or already dirty within the same snap context.
1103 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1104 loff_t pos, unsigned len, unsigned flags,
1105 struct page **pagep, void **fsdata)
1107 struct inode *inode = file_inode(file);
1109 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1114 page = grab_cache_page_write_begin(mapping, index, 0);
1119 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1120 inode, page, (int)pos, (int)len);
1122 r = ceph_update_writeable_page(file, pos, len, page);
1123 } while (r == -EAGAIN);
1129 * we don't do anything in here that simple_write_end doesn't do
1130 * except adjust dirty page accounting and drop read lock on
1133 static int ceph_write_end(struct file *file, struct address_space *mapping,
1134 loff_t pos, unsigned len, unsigned copied,
1135 struct page *page, void *fsdata)
1137 struct inode *inode = file_inode(file);
1138 struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1139 struct ceph_mds_client *mdsc = fsc->mdsc;
1140 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1143 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1144 inode, page, (int)pos, (int)copied, (int)len);
1146 /* zero the stale part of the page if we did a short copy */
1148 zero_user_segment(page, from+copied, len);
1150 /* did file size increase? */
1151 /* (no need for i_size_read(); we caller holds i_mutex */
1152 if (pos+copied > inode->i_size)
1153 check_cap = ceph_inode_set_size(inode, pos+copied);
1155 if (!PageUptodate(page))
1156 SetPageUptodate(page);
1158 set_page_dirty(page);
1161 up_read(&mdsc->snap_rwsem);
1162 page_cache_release(page);
1165 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1171 * we set .direct_IO to indicate direct io is supported, but since we
1172 * intercept O_DIRECT reads and writes early, this function should
1175 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
1176 const struct iovec *iov,
1177 loff_t pos, unsigned long nr_segs)
1183 const struct address_space_operations ceph_aops = {
1184 .readpage = ceph_readpage,
1185 .readpages = ceph_readpages,
1186 .writepage = ceph_writepage,
1187 .writepages = ceph_writepages_start,
1188 .write_begin = ceph_write_begin,
1189 .write_end = ceph_write_end,
1190 .set_page_dirty = ceph_set_page_dirty,
1191 .invalidatepage = ceph_invalidatepage,
1192 .releasepage = ceph_releasepage,
1193 .direct_IO = ceph_direct_io,
1202 * Reuse write_begin here for simplicity.
1204 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1206 struct inode *inode = file_inode(vma->vm_file);
1207 struct page *page = vmf->page;
1208 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1209 loff_t off = page_offset(page);
1213 /* Update time before taking page lock */
1214 file_update_time(vma->vm_file);
1216 size = i_size_read(inode);
1217 if (off + PAGE_CACHE_SIZE <= size)
1218 len = PAGE_CACHE_SIZE;
1220 len = size & ~PAGE_CACHE_MASK;
1222 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
1223 off, len, page, page->index);
1227 ret = VM_FAULT_NOPAGE;
1229 (page->mapping != inode->i_mapping))
1232 ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
1234 /* success. we'll keep the page locked. */
1235 set_page_dirty(page);
1236 up_read(&mdsc->snap_rwsem);
1237 ret = VM_FAULT_LOCKED;
1242 ret = VM_FAULT_SIGBUS;
1245 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1246 if (ret != VM_FAULT_LOCKED)
1251 static struct vm_operations_struct ceph_vmops = {
1252 .fault = filemap_fault,
1253 .page_mkwrite = ceph_page_mkwrite,
1254 .remap_pages = generic_file_remap_pages,
1257 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1259 struct address_space *mapping = file->f_mapping;
1261 if (!mapping->a_ops->readpage)
1263 file_accessed(file);
1264 vma->vm_ops = &ceph_vmops;