4 * Write file data over NFS.
6 * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
9 #include <linux/types.h>
10 #include <linux/slab.h>
12 #include <linux/pagemap.h>
13 #include <linux/file.h>
14 #include <linux/writeback.h>
15 #include <linux/swap.h>
16 #include <linux/migrate.h>
18 #include <linux/sunrpc/clnt.h>
19 #include <linux/nfs_fs.h>
20 #include <linux/nfs_mount.h>
21 #include <linux/nfs_page.h>
22 #include <linux/backing-dev.h>
23 #include <linux/export.h>
25 #include <asm/uaccess.h>
27 #include "delegation.h"
36 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
38 #define MIN_POOL_WRITE (32)
39 #define MIN_POOL_COMMIT (4)
42 * Local function declarations
44 static void nfs_redirty_request(struct nfs_page *req);
45 static const struct rpc_call_ops nfs_commit_ops;
46 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
47 static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
48 static const struct nfs_rw_ops nfs_rw_write_ops;
49 static void nfs_clear_request_commit(struct nfs_page *req);
50 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
52 static struct nfs_page *
53 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
56 static struct kmem_cache *nfs_wdata_cachep;
57 static mempool_t *nfs_wdata_mempool;
58 static struct kmem_cache *nfs_cdata_cachep;
59 static mempool_t *nfs_commit_mempool;
61 struct nfs_commit_data *nfs_commitdata_alloc(void)
63 struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
66 memset(p, 0, sizeof(*p));
67 INIT_LIST_HEAD(&p->pages);
71 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
73 void nfs_commit_free(struct nfs_commit_data *p)
75 mempool_free(p, nfs_commit_mempool);
77 EXPORT_SYMBOL_GPL(nfs_commit_free);
79 static struct nfs_pgio_header *nfs_writehdr_alloc(void)
81 struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
84 memset(p, 0, sizeof(*p));
88 static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
90 mempool_free(hdr, nfs_wdata_mempool);
93 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
97 set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
101 * nfs_page_find_head_request_locked - find head request associated with @page
103 * must be called while holding the inode lock.
105 * returns matching head request with reference held, or NULL if not found.
107 static struct nfs_page *
108 nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page)
110 struct nfs_page *req = NULL;
112 if (PagePrivate(page))
113 req = (struct nfs_page *)page_private(page);
114 else if (unlikely(PageSwapCache(page)))
115 req = nfs_page_search_commits_for_head_request_locked(nfsi,
119 WARN_ON_ONCE(req->wb_head != req);
120 kref_get(&req->wb_kref);
127 * nfs_page_find_head_request - find head request associated with @page
129 * returns matching head request with reference held, or NULL if not found.
131 static struct nfs_page *nfs_page_find_head_request(struct page *page)
133 struct inode *inode = page_file_mapping(page)->host;
134 struct nfs_page *req = NULL;
136 spin_lock(&inode->i_lock);
137 req = nfs_page_find_head_request_locked(NFS_I(inode), page);
138 spin_unlock(&inode->i_lock);
142 /* Adjust the file length if we're writing beyond the end */
143 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
145 struct inode *inode = page_file_mapping(page)->host;
149 spin_lock(&inode->i_lock);
150 i_size = i_size_read(inode);
151 end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
152 if (i_size > 0 && page_file_index(page) < end_index)
154 end = page_file_offset(page) + ((loff_t)offset+count);
157 i_size_write(inode, end);
158 nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
160 spin_unlock(&inode->i_lock);
163 /* A writeback failed: mark the page as bad, and invalidate the page cache */
164 static void nfs_set_pageerror(struct page *page)
166 nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
170 * nfs_page_group_search_locked
171 * @head - head request of page group
172 * @page_offset - offset into page
174 * Search page group with head @head to find a request that contains the
175 * page offset @page_offset.
177 * Returns a pointer to the first matching nfs request, or NULL if no
180 * Must be called with the page group lock held
182 static struct nfs_page *
183 nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
185 struct nfs_page *req;
187 WARN_ON_ONCE(head != head->wb_head);
188 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_head->wb_flags));
192 if (page_offset >= req->wb_pgbase &&
193 page_offset < (req->wb_pgbase + req->wb_bytes))
196 req = req->wb_this_page;
197 } while (req != head);
203 * nfs_page_group_covers_page
204 * @head - head request of page group
206 * Return true if the page group with head @head covers the whole page,
207 * returns false otherwise
209 static bool nfs_page_group_covers_page(struct nfs_page *req)
211 struct nfs_page *tmp;
212 unsigned int pos = 0;
213 unsigned int len = nfs_page_length(req->wb_page);
215 nfs_page_group_lock(req, false);
218 tmp = nfs_page_group_search_locked(req->wb_head, pos);
220 /* no way this should happen */
221 WARN_ON_ONCE(tmp->wb_pgbase != pos);
222 pos += tmp->wb_bytes - (pos - tmp->wb_pgbase);
224 } while (tmp && pos < len);
226 nfs_page_group_unlock(req);
227 WARN_ON_ONCE(pos > len);
231 /* We can set the PG_uptodate flag if we see that a write request
232 * covers the full page.
234 static void nfs_mark_uptodate(struct nfs_page *req)
236 if (PageUptodate(req->wb_page))
238 if (!nfs_page_group_covers_page(req))
240 SetPageUptodate(req->wb_page);
243 static int wb_priority(struct writeback_control *wbc)
246 if (wbc->for_reclaim)
247 return FLUSH_HIGHPRI | FLUSH_STABLE;
248 if (wbc->sync_mode == WB_SYNC_ALL)
249 ret = FLUSH_COND_STABLE;
250 if (wbc->for_kupdate || wbc->for_background)
256 * NFS congestion control
259 int nfs_congestion_kb;
261 #define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10))
262 #define NFS_CONGESTION_OFF_THRESH \
263 (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
265 static void nfs_set_page_writeback(struct page *page)
267 struct nfs_server *nfss = NFS_SERVER(page_file_mapping(page)->host);
268 int ret = test_set_page_writeback(page);
270 WARN_ON_ONCE(ret != 0);
272 if (atomic_long_inc_return(&nfss->writeback) >
273 NFS_CONGESTION_ON_THRESH) {
274 set_bdi_congested(&nfss->backing_dev_info,
279 static void nfs_end_page_writeback(struct nfs_page *req)
281 struct inode *inode = page_file_mapping(req->wb_page)->host;
282 struct nfs_server *nfss = NFS_SERVER(inode);
284 if (!nfs_page_group_sync_on_bit(req, PG_WB_END))
287 end_page_writeback(req->wb_page);
288 if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
289 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
293 /* nfs_page_group_clear_bits
294 * @req - an nfs request
295 * clears all page group related bits from @req
298 nfs_page_group_clear_bits(struct nfs_page *req)
300 clear_bit(PG_TEARDOWN, &req->wb_flags);
301 clear_bit(PG_UNLOCKPAGE, &req->wb_flags);
302 clear_bit(PG_UPTODATE, &req->wb_flags);
303 clear_bit(PG_WB_END, &req->wb_flags);
304 clear_bit(PG_REMOVE, &req->wb_flags);
309 * nfs_unroll_locks_and_wait - unlock all newly locked reqs and wait on @req
311 * this is a helper function for nfs_lock_and_join_requests
313 * @inode - inode associated with request page group, must be holding inode lock
314 * @head - head request of page group, must be holding head lock
315 * @req - request that couldn't lock and needs to wait on the req bit lock
316 * @nonblock - if true, don't actually wait
318 * NOTE: this must be called holding page_group bit lock and inode spin lock
319 * and BOTH will be released before returning.
321 * returns 0 on success, < 0 on error.
324 nfs_unroll_locks_and_wait(struct inode *inode, struct nfs_page *head,
325 struct nfs_page *req, bool nonblock)
326 __releases(&inode->i_lock)
328 struct nfs_page *tmp;
331 /* relinquish all the locks successfully grabbed this run */
332 for (tmp = head ; tmp != req; tmp = tmp->wb_this_page)
333 nfs_unlock_request(tmp);
335 WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
337 /* grab a ref on the request that will be waited on */
338 kref_get(&req->wb_kref);
340 nfs_page_group_unlock(head);
341 spin_unlock(&inode->i_lock);
343 /* release ref from nfs_page_find_head_request_locked */
344 nfs_release_request(head);
347 ret = nfs_wait_on_request(req);
350 nfs_release_request(req);
356 * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
358 * @destroy_list - request list (using wb_this_page) terminated by @old_head
359 * @old_head - the old head of the list
361 * All subrequests must be locked and removed from all lists, so at this point
362 * they are only "active" in this function, and possibly in nfs_wait_on_request
363 * with a reference held by some other context.
366 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
367 struct nfs_page *old_head)
369 while (destroy_list) {
370 struct nfs_page *subreq = destroy_list;
372 destroy_list = (subreq->wb_this_page == old_head) ?
373 NULL : subreq->wb_this_page;
375 WARN_ON_ONCE(old_head != subreq->wb_head);
377 /* make sure old group is not used */
378 subreq->wb_head = subreq;
379 subreq->wb_this_page = subreq;
381 /* subreq is now totally disconnected from page group or any
382 * write / commit lists. last chance to wake any waiters */
383 nfs_unlock_request(subreq);
385 if (!test_bit(PG_TEARDOWN, &subreq->wb_flags)) {
386 /* release ref on old head request */
387 nfs_release_request(old_head);
389 nfs_page_group_clear_bits(subreq);
391 /* release the PG_INODE_REF reference */
392 if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags))
393 nfs_release_request(subreq);
397 WARN_ON_ONCE(test_bit(PG_CLEAN, &subreq->wb_flags));
398 /* zombie requests have already released the last
399 * reference and were waiting on the rest of the
400 * group to complete. Since it's no longer part of a
401 * group, simply free the request */
402 nfs_page_group_clear_bits(subreq);
403 nfs_free_request(subreq);
409 * nfs_lock_and_join_requests - join all subreqs to the head req and return
410 * a locked reference, cancelling any pending
411 * operations for this page.
413 * @page - the page used to lookup the "page group" of nfs_page structures
414 * @nonblock - if true, don't block waiting for request locks
416 * This function joins all sub requests to the head request by first
417 * locking all requests in the group, cancelling any pending operations
418 * and finally updating the head request to cover the whole range covered by
419 * the (former) group. All subrequests are removed from any write or commit
420 * lists, unlinked from the group and destroyed.
422 * Returns a locked, referenced pointer to the head request - which after
423 * this call is guaranteed to be the only request associated with the page.
424 * Returns NULL if no requests are found for @page, or a ERR_PTR if an
425 * error was encountered.
427 static struct nfs_page *
428 nfs_lock_and_join_requests(struct page *page, bool nonblock)
430 struct inode *inode = page_file_mapping(page)->host;
431 struct nfs_page *head, *subreq;
432 struct nfs_page *destroy_list = NULL;
433 unsigned int total_bytes;
439 WARN_ON_ONCE(destroy_list);
441 spin_lock(&inode->i_lock);
444 * A reference is taken only on the head request which acts as a
445 * reference to the whole page group - the group will not be destroyed
446 * until the head reference is released.
448 head = nfs_page_find_head_request_locked(NFS_I(inode), page);
451 spin_unlock(&inode->i_lock);
455 /* holding inode lock, so always make a non-blocking call to try the
457 ret = nfs_page_group_lock(head, true);
459 spin_unlock(&inode->i_lock);
461 if (!nonblock && ret == -EAGAIN) {
462 nfs_page_group_lock_wait(head);
463 nfs_release_request(head);
467 nfs_release_request(head);
471 /* lock each request in the page group */
475 * Subrequests are always contiguous, non overlapping
476 * and in order. If not, it's a programming error.
478 WARN_ON_ONCE(subreq->wb_offset !=
479 (head->wb_offset + total_bytes));
481 /* keep track of how many bytes this group covers */
482 total_bytes += subreq->wb_bytes;
484 if (!nfs_lock_request(subreq)) {
485 /* releases page group bit lock and
486 * inode spin lock and all references */
487 ret = nfs_unroll_locks_and_wait(inode, head,
496 subreq = subreq->wb_this_page;
497 } while (subreq != head);
499 /* Now that all requests are locked, make sure they aren't on any list.
500 * Commit list removal accounting is done after locks are dropped */
503 nfs_clear_request_commit(subreq);
504 subreq = subreq->wb_this_page;
505 } while (subreq != head);
507 /* unlink subrequests from head, destroy them later */
508 if (head->wb_this_page != head) {
509 /* destroy list will be terminated by head */
510 destroy_list = head->wb_this_page;
511 head->wb_this_page = head;
513 /* change head request to cover whole range that
514 * the former page group covered */
515 head->wb_bytes = total_bytes;
519 * prepare head request to be added to new pgio descriptor
521 nfs_page_group_clear_bits(head);
524 * some part of the group was still on the inode list - otherwise
525 * the group wouldn't be involved in async write.
526 * grab a reference for the head request, iff it needs one.
528 if (!test_and_set_bit(PG_INODE_REF, &head->wb_flags))
529 kref_get(&head->wb_kref);
531 nfs_page_group_unlock(head);
533 /* drop lock to clean uprequests on destroy list */
534 spin_unlock(&inode->i_lock);
536 nfs_destroy_unlinked_subrequests(destroy_list, head);
538 /* still holds ref on head from nfs_page_find_head_request_locked
539 * and still has lock on head from lock loop */
544 * Find an associated nfs write request, and prepare to flush it out
545 * May return an error if the user signalled nfs_wait_on_request().
547 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
548 struct page *page, bool nonblock)
550 struct nfs_page *req;
553 req = nfs_lock_and_join_requests(page, nonblock);
560 nfs_set_page_writeback(page);
561 WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
564 if (!nfs_pageio_add_request(pgio, req)) {
565 nfs_redirty_request(req);
566 ret = pgio->pg_error;
572 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
574 struct inode *inode = page_file_mapping(page)->host;
577 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
578 nfs_inc_stats(inode, NFSIOS_WRITEPAGES);
580 nfs_pageio_cond_complete(pgio, page_file_index(page));
581 ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
582 if (ret == -EAGAIN) {
583 redirty_page_for_writepage(wbc, page);
590 * Write an mmapped page to the server.
592 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
594 struct nfs_pageio_descriptor pgio;
597 nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc),
598 false, &nfs_async_write_completion_ops);
599 err = nfs_do_writepage(page, wbc, &pgio);
600 nfs_pageio_complete(&pgio);
603 if (pgio.pg_error < 0)
604 return pgio.pg_error;
608 int nfs_writepage(struct page *page, struct writeback_control *wbc)
612 ret = nfs_writepage_locked(page, wbc);
617 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
621 ret = nfs_do_writepage(page, wbc, data);
626 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
628 struct inode *inode = mapping->host;
629 unsigned long *bitlock = &NFS_I(inode)->flags;
630 struct nfs_pageio_descriptor pgio;
633 /* Stop dirtying of new pages while we sync */
634 err = wait_on_bit_lock_action(bitlock, NFS_INO_FLUSHING,
635 nfs_wait_bit_killable, TASK_KILLABLE);
639 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
641 nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false,
642 &nfs_async_write_completion_ops);
643 err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
644 nfs_pageio_complete(&pgio);
646 clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
647 smp_mb__after_atomic();
648 wake_up_bit(bitlock, NFS_INO_FLUSHING);
661 * Insert a write request into an inode
663 static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
665 struct nfs_inode *nfsi = NFS_I(inode);
667 WARN_ON_ONCE(req->wb_this_page != req);
669 /* Lock the request! */
670 nfs_lock_request(req);
672 spin_lock(&inode->i_lock);
673 if (!nfsi->nrequests &&
674 NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
677 * Swap-space should not get truncated. Hence no need to plug the race
678 * with invalidate/truncate.
680 if (likely(!PageSwapCache(req->wb_page))) {
681 set_bit(PG_MAPPED, &req->wb_flags);
682 SetPagePrivate(req->wb_page);
683 set_page_private(req->wb_page, (unsigned long)req);
686 /* this a head request for a page group - mark it as having an
687 * extra reference so sub groups can follow suit.
688 * This flag also informs pgio layer when to bump nrequests when
689 * adding subrequests. */
690 WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
691 kref_get(&req->wb_kref);
692 spin_unlock(&inode->i_lock);
696 * Remove a write request from an inode
698 static void nfs_inode_remove_request(struct nfs_page *req)
700 struct inode *inode = req->wb_context->dentry->d_inode;
701 struct nfs_inode *nfsi = NFS_I(inode);
702 struct nfs_page *head;
704 if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
707 spin_lock(&inode->i_lock);
708 if (likely(!PageSwapCache(head->wb_page))) {
709 set_page_private(head->wb_page, 0);
710 ClearPagePrivate(head->wb_page);
711 smp_mb__after_atomic();
712 wake_up_page(head->wb_page, PG_private);
713 clear_bit(PG_MAPPED, &head->wb_flags);
716 spin_unlock(&inode->i_lock);
718 spin_lock(&inode->i_lock);
720 spin_unlock(&inode->i_lock);
723 if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags))
724 nfs_release_request(req);
728 nfs_mark_request_dirty(struct nfs_page *req)
730 __set_page_dirty_nobuffers(req->wb_page);
734 * nfs_page_search_commits_for_head_request_locked
736 * Search through commit lists on @inode for the head request for @page.
737 * Must be called while holding the inode (which is cinfo) lock.
739 * Returns the head request if found, or NULL if not found.
741 static struct nfs_page *
742 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
745 struct nfs_page *freq, *t;
746 struct nfs_commit_info cinfo;
747 struct inode *inode = &nfsi->vfs_inode;
749 nfs_init_cinfo_from_inode(&cinfo, inode);
751 /* search through pnfs commit lists */
752 freq = pnfs_search_commit_reqs(inode, &cinfo, page);
754 return freq->wb_head;
756 /* Linearly search the commit list for the correct request */
757 list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
758 if (freq->wb_page == page)
759 return freq->wb_head;
766 * nfs_request_add_commit_list - add request to a commit list
767 * @req: pointer to a struct nfs_page
768 * @dst: commit list head
769 * @cinfo: holds list lock and accounting info
771 * This sets the PG_CLEAN bit, updates the cinfo count of
772 * number of outstanding requests requiring a commit as well as
775 * The caller must _not_ hold the cinfo->lock, but must be
776 * holding the nfs_page lock.
779 nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
780 struct nfs_commit_info *cinfo)
782 set_bit(PG_CLEAN, &(req)->wb_flags);
783 spin_lock(cinfo->lock);
784 nfs_list_add_request(req, dst);
785 cinfo->mds->ncommit++;
786 spin_unlock(cinfo->lock);
788 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
789 inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
791 __mark_inode_dirty(req->wb_context->dentry->d_inode,
795 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
798 * nfs_request_remove_commit_list - Remove request from a commit list
799 * @req: pointer to a nfs_page
800 * @cinfo: holds list lock and accounting info
802 * This clears the PG_CLEAN bit, and updates the cinfo's count of
803 * number of outstanding requests requiring a commit
804 * It does not update the MM page stats.
806 * The caller _must_ hold the cinfo->lock and the nfs_page lock.
809 nfs_request_remove_commit_list(struct nfs_page *req,
810 struct nfs_commit_info *cinfo)
812 if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
814 nfs_list_remove_request(req);
815 cinfo->mds->ncommit--;
817 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
819 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
822 cinfo->lock = &inode->i_lock;
823 cinfo->mds = &NFS_I(inode)->commit_info;
824 cinfo->ds = pnfs_get_ds_info(inode);
826 cinfo->completion_ops = &nfs_commit_completion_ops;
829 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
831 struct nfs_direct_req *dreq)
834 nfs_init_cinfo_from_dreq(cinfo, dreq);
836 nfs_init_cinfo_from_inode(cinfo, inode);
838 EXPORT_SYMBOL_GPL(nfs_init_cinfo);
841 * Add a request to the inode's commit list.
844 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
845 struct nfs_commit_info *cinfo)
847 if (pnfs_mark_request_commit(req, lseg, cinfo))
849 nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
853 nfs_clear_page_commit(struct page *page)
855 dec_zone_page_state(page, NR_UNSTABLE_NFS);
856 dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE);
859 /* Called holding inode (/cinfo) lock */
861 nfs_clear_request_commit(struct nfs_page *req)
863 if (test_bit(PG_CLEAN, &req->wb_flags)) {
864 struct inode *inode = req->wb_context->dentry->d_inode;
865 struct nfs_commit_info cinfo;
867 nfs_init_cinfo_from_inode(&cinfo, inode);
868 if (!pnfs_clear_request_commit(req, &cinfo)) {
869 nfs_request_remove_commit_list(req, &cinfo);
871 nfs_clear_page_commit(req->wb_page);
875 int nfs_write_need_commit(struct nfs_pgio_header *hdr)
877 if (hdr->verf.committed == NFS_DATA_SYNC)
878 return hdr->lseg == NULL;
879 return hdr->verf.committed != NFS_FILE_SYNC;
882 static void nfs_write_completion(struct nfs_pgio_header *hdr)
884 struct nfs_commit_info cinfo;
885 unsigned long bytes = 0;
887 if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
889 nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
890 while (!list_empty(&hdr->pages)) {
891 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
893 bytes += req->wb_bytes;
894 nfs_list_remove_request(req);
895 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
896 (hdr->good_bytes < bytes)) {
897 nfs_set_pageerror(req->wb_page);
898 nfs_context_set_write_error(req->wb_context, hdr->error);
901 if (nfs_write_need_commit(hdr)) {
902 memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
903 nfs_mark_request_commit(req, hdr->lseg, &cinfo);
907 nfs_inode_remove_request(req);
909 nfs_unlock_request(req);
910 nfs_end_page_writeback(req);
911 nfs_release_request(req);
918 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
920 return cinfo->mds->ncommit;
923 /* cinfo->lock held by caller */
925 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
926 struct nfs_commit_info *cinfo, int max)
928 struct nfs_page *req, *tmp;
931 list_for_each_entry_safe(req, tmp, src, wb_list) {
932 if (!nfs_lock_request(req))
934 kref_get(&req->wb_kref);
935 if (cond_resched_lock(cinfo->lock))
936 list_safe_reset_next(req, tmp, wb_list);
937 nfs_request_remove_commit_list(req, cinfo);
938 nfs_list_add_request(req, dst);
940 if ((ret == max) && !cinfo->dreq)
947 * nfs_scan_commit - Scan an inode for commit requests
948 * @inode: NFS inode to scan
949 * @dst: mds destination list
950 * @cinfo: mds and ds lists of reqs ready to commit
952 * Moves requests from the inode's 'commit' request list.
953 * The requests are *not* checked to ensure that they form a contiguous set.
956 nfs_scan_commit(struct inode *inode, struct list_head *dst,
957 struct nfs_commit_info *cinfo)
961 spin_lock(cinfo->lock);
962 if (cinfo->mds->ncommit > 0) {
963 const int max = INT_MAX;
965 ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
967 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
969 spin_unlock(cinfo->lock);
974 * Search for an existing write request, and attempt to update
975 * it to reflect a new dirty region on a given page.
977 * If the attempt fails, then the existing request is flushed out
980 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
985 struct nfs_page *req;
990 if (!PagePrivate(page))
993 end = offset + bytes;
994 spin_lock(&inode->i_lock);
997 req = nfs_page_find_head_request_locked(NFS_I(inode), page);
1001 /* should be handled by nfs_flush_incompatible */
1002 WARN_ON_ONCE(req->wb_head != req);
1003 WARN_ON_ONCE(req->wb_this_page != req);
1005 rqend = req->wb_offset + req->wb_bytes;
1007 * Tell the caller to flush out the request if
1008 * the offsets are non-contiguous.
1009 * Note: nfs_flush_incompatible() will already
1010 * have flushed out requests having wrong owners.
1013 || end < req->wb_offset)
1016 if (nfs_lock_request(req))
1019 /* The request is locked, so wait and then retry */
1020 spin_unlock(&inode->i_lock);
1021 error = nfs_wait_on_request(req);
1022 nfs_release_request(req);
1025 spin_lock(&inode->i_lock);
1028 /* Okay, the request matches. Update the region */
1029 if (offset < req->wb_offset) {
1030 req->wb_offset = offset;
1031 req->wb_pgbase = offset;
1034 req->wb_bytes = end - req->wb_offset;
1036 req->wb_bytes = rqend - req->wb_offset;
1039 nfs_clear_request_commit(req);
1040 spin_unlock(&inode->i_lock);
1043 spin_unlock(&inode->i_lock);
1044 nfs_release_request(req);
1045 error = nfs_wb_page(inode, page);
1047 return ERR_PTR(error);
1051 * Try to update an existing write request, or create one if there is none.
1053 * Note: Should always be called with the Page Lock held to prevent races
1054 * if we have to add a new request. Also assumes that the caller has
1055 * already called nfs_flush_incompatible() if necessary.
1057 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
1058 struct page *page, unsigned int offset, unsigned int bytes)
1060 struct inode *inode = page_file_mapping(page)->host;
1061 struct nfs_page *req;
1063 req = nfs_try_to_update_request(inode, page, offset, bytes);
1066 req = nfs_create_request(ctx, page, NULL, offset, bytes);
1069 nfs_inode_add_request(inode, req);
1074 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
1075 unsigned int offset, unsigned int count)
1077 struct nfs_page *req;
1079 req = nfs_setup_write_request(ctx, page, offset, count);
1081 return PTR_ERR(req);
1082 /* Update file length */
1083 nfs_grow_file(page, offset, count);
1084 nfs_mark_uptodate(req);
1085 nfs_mark_request_dirty(req);
1086 nfs_unlock_and_release_request(req);
1090 int nfs_flush_incompatible(struct file *file, struct page *page)
1092 struct nfs_open_context *ctx = nfs_file_open_context(file);
1093 struct nfs_lock_context *l_ctx;
1094 struct file_lock_context *flctx = file_inode(file)->i_flctx;
1095 struct nfs_page *req;
1096 int do_flush, status;
1098 * Look for a request corresponding to this page. If there
1099 * is one, and it belongs to another file, we flush it out
1100 * before we try to copy anything into the page. Do this
1101 * due to the lack of an ACCESS-type call in NFSv2.
1102 * Also do the same if we find a request from an existing
1106 req = nfs_page_find_head_request(page);
1109 l_ctx = req->wb_lock_context;
1110 do_flush = req->wb_page != page || req->wb_context != ctx;
1111 /* for now, flush if more than 1 request in page_group */
1112 do_flush |= req->wb_this_page != req;
1113 if (l_ctx && flctx &&
1114 !(list_empty_careful(&flctx->flc_posix) &&
1115 list_empty_careful(&flctx->flc_flock))) {
1116 do_flush |= l_ctx->lockowner.l_owner != current->files
1117 || l_ctx->lockowner.l_pid != current->tgid;
1119 nfs_release_request(req);
1122 status = nfs_wb_page(page_file_mapping(page)->host, page);
1123 } while (status == 0);
1128 * Avoid buffered writes when a open context credential's key would
1131 * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1133 * Return 0 and set a credential flag which triggers the inode to flush
1134 * and performs NFS_FILE_SYNC writes if the key will expired within
1135 * RPC_KEY_EXPIRE_TIMEO.
1138 nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1140 struct nfs_open_context *ctx = nfs_file_open_context(filp);
1141 struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1143 return rpcauth_key_timeout_notify(auth, ctx->cred);
1147 * Test if the open context credential key is marked to expire soon.
1149 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx)
1151 return rpcauth_cred_key_to_expire(ctx->cred);
1155 * If the page cache is marked as unsafe or invalid, then we can't rely on
1156 * the PageUptodate() flag. In this case, we will need to turn off
1157 * write optimisations that depend on the page contents being correct.
1159 static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
1161 struct nfs_inode *nfsi = NFS_I(inode);
1163 if (nfs_have_delegated_attributes(inode))
1165 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
1168 if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags))
1171 if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
1173 return PageUptodate(page) != 0;
1177 is_whole_file_wrlock(struct file_lock *fl)
1179 return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1180 fl->fl_type == F_WRLCK;
1183 /* If we know the page is up to date, and we're not using byte range locks (or
1184 * if we have the whole file locked for writing), it may be more efficient to
1185 * extend the write to cover the entire page in order to avoid fragmentation
1188 * If the file is opened for synchronous writes then we can just skip the rest
1191 static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
1194 struct file_lock_context *flctx = inode->i_flctx;
1195 struct file_lock *fl;
1197 if (file->f_flags & O_DSYNC)
1199 if (!nfs_write_pageuptodate(page, inode))
1201 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1203 if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1204 list_empty_careful(&flctx->flc_posix)))
1207 /* Check to see if there are whole file write locks */
1209 spin_lock(&flctx->flc_lock);
1210 if (!list_empty(&flctx->flc_posix)) {
1211 fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1213 if (is_whole_file_wrlock(fl))
1215 } else if (!list_empty(&flctx->flc_flock)) {
1216 fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1218 if (fl->fl_type == F_WRLCK)
1221 spin_unlock(&flctx->flc_lock);
1226 * Update and possibly write a cached page of an NFS file.
1228 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1229 * things with a page scheduled for an RPC call (e.g. invalidate it).
1231 int nfs_updatepage(struct file *file, struct page *page,
1232 unsigned int offset, unsigned int count)
1234 struct nfs_open_context *ctx = nfs_file_open_context(file);
1235 struct inode *inode = page_file_mapping(page)->host;
1238 nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1240 dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n",
1241 file, count, (long long)(page_file_offset(page) + offset));
1243 if (nfs_can_extend_write(file, page, inode)) {
1244 count = max(count + offset, nfs_page_length(page));
1248 status = nfs_writepage_setup(ctx, page, offset, count);
1250 nfs_set_pageerror(page);
1252 __set_page_dirty_nobuffers(page);
1254 dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
1255 status, (long long)i_size_read(inode));
1259 static int flush_task_priority(int how)
1261 switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1263 return RPC_PRIORITY_HIGH;
1265 return RPC_PRIORITY_LOW;
1267 return RPC_PRIORITY_NORMAL;
1270 static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1271 struct rpc_message *msg,
1272 struct rpc_task_setup *task_setup_data, int how)
1274 struct inode *inode = hdr->inode;
1275 int priority = flush_task_priority(how);
1277 task_setup_data->priority = priority;
1278 NFS_PROTO(inode)->write_setup(hdr, msg);
1280 nfs4_state_protect_write(NFS_SERVER(inode)->nfs_client,
1281 &task_setup_data->rpc_client, msg, hdr);
1284 /* If a nfs_flush_* function fails, it should remove reqs from @head and
1285 * call this on each, which will prepare them to be retried on next
1286 * writeback using standard nfs.
1288 static void nfs_redirty_request(struct nfs_page *req)
1290 nfs_mark_request_dirty(req);
1291 nfs_unlock_request(req);
1292 nfs_end_page_writeback(req);
1293 nfs_release_request(req);
1296 static void nfs_async_write_error(struct list_head *head)
1298 struct nfs_page *req;
1300 while (!list_empty(head)) {
1301 req = nfs_list_entry(head->next);
1302 nfs_list_remove_request(req);
1303 nfs_redirty_request(req);
1307 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1308 .error_cleanup = nfs_async_write_error,
1309 .completion = nfs_write_completion,
1312 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1313 struct inode *inode, int ioflags, bool force_mds,
1314 const struct nfs_pgio_completion_ops *compl_ops)
1316 struct nfs_server *server = NFS_SERVER(inode);
1317 const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1319 #ifdef CONFIG_NFS_V4_1
1320 if (server->pnfs_curr_ld && !force_mds)
1321 pg_ops = server->pnfs_curr_ld->pg_write_ops;
1323 nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1324 server->wsize, ioflags);
1326 EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1328 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1330 pgio->pg_ops = &nfs_pgio_rw_ops;
1331 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1333 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1336 void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1338 struct nfs_commit_data *data = calldata;
1340 NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1343 static void nfs_writeback_release_common(struct nfs_pgio_header *hdr)
1349 * Special version of should_remove_suid() that ignores capabilities.
1351 static int nfs_should_remove_suid(const struct inode *inode)
1353 umode_t mode = inode->i_mode;
1356 /* suid always must be killed */
1357 if (unlikely(mode & S_ISUID))
1358 kill = ATTR_KILL_SUID;
1361 * sgid without any exec bits is just a mandatory locking mark; leave
1362 * it alone. If some exec bits are set, it's a real sgid; kill it.
1364 if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1365 kill |= ATTR_KILL_SGID;
1367 if (unlikely(kill && S_ISREG(mode)))
1374 * This function is called when the WRITE call is complete.
1376 static int nfs_writeback_done(struct rpc_task *task,
1377 struct nfs_pgio_header *hdr,
1378 struct inode *inode)
1383 * ->write_done will attempt to use post-op attributes to detect
1384 * conflicting writes by other clients. A strict interpretation
1385 * of close-to-open would allow us to continue caching even if
1386 * another writer had changed the file, but some applications
1387 * depend on tighter cache coherency when writing.
1389 status = NFS_PROTO(inode)->write_done(task, hdr);
1392 nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1394 if (hdr->res.verf->committed < hdr->args.stable &&
1395 task->tk_status >= 0) {
1396 /* We tried a write call, but the server did not
1397 * commit data to stable storage even though we
1399 * Note: There is a known bug in Tru64 < 5.0 in which
1400 * the server reports NFS_DATA_SYNC, but performs
1401 * NFS_FILE_SYNC. We therefore implement this checking
1402 * as a dprintk() in order to avoid filling syslog.
1404 static unsigned long complain;
1406 /* Note this will print the MDS for a DS write */
1407 if (time_before(complain, jiffies)) {
1408 dprintk("NFS: faulty NFS server %s:"
1409 " (committed = %d) != (stable = %d)\n",
1410 NFS_SERVER(inode)->nfs_client->cl_hostname,
1411 hdr->res.verf->committed, hdr->args.stable);
1412 complain = jiffies + 300 * HZ;
1416 /* Deal with the suid/sgid bit corner case */
1417 if (nfs_should_remove_suid(inode))
1418 nfs_mark_for_revalidate(inode);
1423 * This function is called when the WRITE call is complete.
1425 static void nfs_writeback_result(struct rpc_task *task,
1426 struct nfs_pgio_header *hdr)
1428 struct nfs_pgio_args *argp = &hdr->args;
1429 struct nfs_pgio_res *resp = &hdr->res;
1431 if (resp->count < argp->count) {
1432 static unsigned long complain;
1434 /* This a short write! */
1435 nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1437 /* Has the server at least made some progress? */
1438 if (resp->count == 0) {
1439 if (time_before(complain, jiffies)) {
1441 "NFS: Server wrote zero bytes, expected %u.\n",
1443 complain = jiffies + 300 * HZ;
1445 nfs_set_pgio_error(hdr, -EIO, argp->offset);
1446 task->tk_status = -EIO;
1449 /* Was this an NFSv2 write or an NFSv3 stable write? */
1450 if (resp->verf->committed != NFS_UNSTABLE) {
1451 /* Resend from where the server left off */
1452 hdr->mds_offset += resp->count;
1453 argp->offset += resp->count;
1454 argp->pgbase += resp->count;
1455 argp->count -= resp->count;
1457 /* Resend as a stable write in order to avoid
1458 * headaches in the case of a server crash.
1460 argp->stable = NFS_FILE_SYNC;
1462 rpc_restart_call_prepare(task);
1467 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1471 if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1475 ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1477 nfs_wait_bit_killable,
1479 return (ret < 0) ? ret : 1;
1482 static void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1484 clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1485 smp_mb__after_atomic();
1486 wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1489 void nfs_commitdata_release(struct nfs_commit_data *data)
1491 put_nfs_open_context(data->context);
1492 nfs_commit_free(data);
1494 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1496 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1497 const struct rpc_call_ops *call_ops,
1500 struct rpc_task *task;
1501 int priority = flush_task_priority(how);
1502 struct rpc_message msg = {
1503 .rpc_argp = &data->args,
1504 .rpc_resp = &data->res,
1505 .rpc_cred = data->cred,
1507 struct rpc_task_setup task_setup_data = {
1508 .task = &data->task,
1510 .rpc_message = &msg,
1511 .callback_ops = call_ops,
1512 .callback_data = data,
1513 .workqueue = nfsiod_workqueue,
1514 .flags = RPC_TASK_ASYNC | flags,
1515 .priority = priority,
1517 /* Set up the initial task struct. */
1518 NFS_PROTO(data->inode)->commit_setup(data, &msg);
1520 dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1522 nfs4_state_protect(NFS_SERVER(data->inode)->nfs_client,
1523 NFS_SP4_MACH_CRED_COMMIT, &task_setup_data.rpc_client, &msg);
1525 task = rpc_run_task(&task_setup_data);
1527 return PTR_ERR(task);
1528 if (how & FLUSH_SYNC)
1529 rpc_wait_for_completion_task(task);
1533 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1535 static loff_t nfs_get_lwb(struct list_head *head)
1538 struct nfs_page *req;
1540 list_for_each_entry(req, head, wb_list)
1541 if (lwb < (req_offset(req) + req->wb_bytes))
1542 lwb = req_offset(req) + req->wb_bytes;
1548 * Set up the argument/result storage required for the RPC call.
1550 void nfs_init_commit(struct nfs_commit_data *data,
1551 struct list_head *head,
1552 struct pnfs_layout_segment *lseg,
1553 struct nfs_commit_info *cinfo)
1555 struct nfs_page *first = nfs_list_entry(head->next);
1556 struct inode *inode = first->wb_context->dentry->d_inode;
1558 /* Set up the RPC argument and reply structs
1559 * NB: take care not to mess about with data->commit et al. */
1561 list_splice_init(head, &data->pages);
1563 data->inode = inode;
1564 data->cred = first->wb_context->cred;
1565 data->lseg = lseg; /* reference transferred */
1566 /* only set lwb for pnfs commit */
1568 data->lwb = nfs_get_lwb(&data->pages);
1569 data->mds_ops = &nfs_commit_ops;
1570 data->completion_ops = cinfo->completion_ops;
1571 data->dreq = cinfo->dreq;
1573 data->args.fh = NFS_FH(data->inode);
1574 /* Note: we always request a commit of the entire inode */
1575 data->args.offset = 0;
1576 data->args.count = 0;
1577 data->context = get_nfs_open_context(first->wb_context);
1578 data->res.fattr = &data->fattr;
1579 data->res.verf = &data->verf;
1580 nfs_fattr_init(&data->fattr);
1582 EXPORT_SYMBOL_GPL(nfs_init_commit);
1584 void nfs_retry_commit(struct list_head *page_list,
1585 struct pnfs_layout_segment *lseg,
1586 struct nfs_commit_info *cinfo)
1588 struct nfs_page *req;
1590 while (!list_empty(page_list)) {
1591 req = nfs_list_entry(page_list->next);
1592 nfs_list_remove_request(req);
1593 nfs_mark_request_commit(req, lseg, cinfo);
1595 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1596 dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
1599 nfs_unlock_and_release_request(req);
1602 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1605 * Commit dirty pages
1608 nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1609 struct nfs_commit_info *cinfo)
1611 struct nfs_commit_data *data;
1613 data = nfs_commitdata_alloc();
1618 /* Set up the argument struct */
1619 nfs_init_commit(data, head, NULL, cinfo);
1620 atomic_inc(&cinfo->mds->rpcs_out);
1621 return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops,
1624 nfs_retry_commit(head, NULL, cinfo);
1625 cinfo->completion_ops->error_cleanup(NFS_I(inode));
1630 * COMMIT call returned
1632 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1634 struct nfs_commit_data *data = calldata;
1636 dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1637 task->tk_pid, task->tk_status);
1639 /* Call the NFS version-specific code */
1640 NFS_PROTO(data->inode)->commit_done(task, data);
1643 static void nfs_commit_release_pages(struct nfs_commit_data *data)
1645 struct nfs_page *req;
1646 int status = data->task.tk_status;
1647 struct nfs_commit_info cinfo;
1648 struct nfs_server *nfss;
1650 while (!list_empty(&data->pages)) {
1651 req = nfs_list_entry(data->pages.next);
1652 nfs_list_remove_request(req);
1653 nfs_clear_page_commit(req->wb_page);
1655 dprintk("NFS: commit (%s/%llu %d@%lld)",
1656 req->wb_context->dentry->d_sb->s_id,
1657 (unsigned long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1659 (long long)req_offset(req));
1661 nfs_context_set_write_error(req->wb_context, status);
1662 nfs_inode_remove_request(req);
1663 dprintk(", error = %d\n", status);
1667 /* Okay, COMMIT succeeded, apparently. Check the verifier
1668 * returned by the server against all stored verfs. */
1669 if (!memcmp(&req->wb_verf, &data->verf.verifier, sizeof(req->wb_verf))) {
1670 /* We have a match */
1671 nfs_inode_remove_request(req);
1675 /* We have a mismatch. Write the page again */
1676 dprintk(" mismatch\n");
1677 nfs_mark_request_dirty(req);
1678 set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
1680 nfs_unlock_and_release_request(req);
1682 nfss = NFS_SERVER(data->inode);
1683 if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1684 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
1686 nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1687 if (atomic_dec_and_test(&cinfo.mds->rpcs_out))
1688 nfs_commit_clear_lock(NFS_I(data->inode));
1691 static void nfs_commit_release(void *calldata)
1693 struct nfs_commit_data *data = calldata;
1695 data->completion_ops->completion(data);
1696 nfs_commitdata_release(calldata);
1699 static const struct rpc_call_ops nfs_commit_ops = {
1700 .rpc_call_prepare = nfs_commit_prepare,
1701 .rpc_call_done = nfs_commit_done,
1702 .rpc_release = nfs_commit_release,
1705 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1706 .completion = nfs_commit_release_pages,
1707 .error_cleanup = nfs_commit_clear_lock,
1710 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1711 int how, struct nfs_commit_info *cinfo)
1715 status = pnfs_commit_list(inode, head, how, cinfo);
1716 if (status == PNFS_NOT_ATTEMPTED)
1717 status = nfs_commit_list(inode, head, how, cinfo);
1721 int nfs_commit_inode(struct inode *inode, int how)
1724 struct nfs_commit_info cinfo;
1725 int may_wait = how & FLUSH_SYNC;
1728 res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1730 goto out_mark_dirty;
1731 nfs_init_cinfo_from_inode(&cinfo, inode);
1732 res = nfs_scan_commit(inode, &head, &cinfo);
1736 error = nfs_generic_commit_list(inode, &head, how, &cinfo);
1740 goto out_mark_dirty;
1741 error = wait_on_bit_action(&NFS_I(inode)->flags,
1743 nfs_wait_bit_killable,
1748 nfs_commit_clear_lock(NFS_I(inode));
1750 /* Note: If we exit without ensuring that the commit is complete,
1751 * we must mark the inode as dirty. Otherwise, future calls to
1752 * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1753 * that the data is on the disk.
1756 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1760 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1762 struct nfs_inode *nfsi = NFS_I(inode);
1763 int flags = FLUSH_SYNC;
1766 /* no commits means nothing needs to be done */
1767 if (!nfsi->commit_info.ncommit)
1770 if (wbc->sync_mode == WB_SYNC_NONE) {
1771 /* Don't commit yet if this is a non-blocking flush and there
1772 * are a lot of outstanding writes for this mapping.
1774 if (nfsi->commit_info.ncommit <= (nfsi->nrequests >> 1))
1775 goto out_mark_dirty;
1777 /* don't wait for the COMMIT response */
1781 ret = nfs_commit_inode(inode, flags);
1783 if (wbc->sync_mode == WB_SYNC_NONE) {
1784 if (ret < wbc->nr_to_write)
1785 wbc->nr_to_write -= ret;
1787 wbc->nr_to_write = 0;
1792 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1796 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1798 return nfs_commit_unstable_pages(inode, wbc);
1800 EXPORT_SYMBOL_GPL(nfs_write_inode);
1803 * flush the inode to disk.
1805 int nfs_wb_all(struct inode *inode)
1807 struct writeback_control wbc = {
1808 .sync_mode = WB_SYNC_ALL,
1809 .nr_to_write = LONG_MAX,
1811 .range_end = LLONG_MAX,
1815 trace_nfs_writeback_inode_enter(inode);
1817 ret = sync_inode(inode, &wbc);
1819 trace_nfs_writeback_inode_exit(inode, ret);
1822 EXPORT_SYMBOL_GPL(nfs_wb_all);
1824 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1826 struct nfs_page *req;
1829 wait_on_page_writeback(page);
1831 /* blocking call to cancel all requests and join to a single (head)
1833 req = nfs_lock_and_join_requests(page, false);
1838 /* all requests from this page have been cancelled by
1839 * nfs_lock_and_join_requests, so just remove the head
1840 * request from the inode / page_private pointer and
1842 nfs_inode_remove_request(req);
1844 * In case nfs_inode_remove_request has marked the
1845 * page as being dirty
1847 cancel_dirty_page(page, PAGE_CACHE_SIZE);
1848 nfs_unlock_and_release_request(req);
1855 * Write back all requests on one page - we do this before reading it.
1857 int nfs_wb_page(struct inode *inode, struct page *page)
1859 loff_t range_start = page_file_offset(page);
1860 loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1861 struct writeback_control wbc = {
1862 .sync_mode = WB_SYNC_ALL,
1864 .range_start = range_start,
1865 .range_end = range_end,
1869 trace_nfs_writeback_page_enter(inode);
1872 wait_on_page_writeback(page);
1873 if (clear_page_dirty_for_io(page)) {
1874 ret = nfs_writepage_locked(page, &wbc);
1880 if (!PagePrivate(page))
1882 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1887 trace_nfs_writeback_page_exit(inode, ret);
1891 #ifdef CONFIG_MIGRATION
1892 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1893 struct page *page, enum migrate_mode mode)
1896 * If PagePrivate is set, then the page is currently associated with
1897 * an in-progress read or write request. Don't try to migrate it.
1899 * FIXME: we could do this in principle, but we'll need a way to ensure
1900 * that we can safely release the inode reference while holding
1903 if (PagePrivate(page))
1906 if (!nfs_fscache_release_page(page, GFP_KERNEL))
1909 return migrate_page(mapping, newpage, page, mode);
1913 int __init nfs_init_writepagecache(void)
1915 nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1916 sizeof(struct nfs_pgio_header),
1917 0, SLAB_HWCACHE_ALIGN,
1919 if (nfs_wdata_cachep == NULL)
1922 nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1924 if (nfs_wdata_mempool == NULL)
1925 goto out_destroy_write_cache;
1927 nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
1928 sizeof(struct nfs_commit_data),
1929 0, SLAB_HWCACHE_ALIGN,
1931 if (nfs_cdata_cachep == NULL)
1932 goto out_destroy_write_mempool;
1934 nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1936 if (nfs_commit_mempool == NULL)
1937 goto out_destroy_commit_cache;
1940 * NFS congestion size, scale with available memory.
1952 * This allows larger machines to have larger/more transfers.
1953 * Limit the default to 256M
1955 nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1956 if (nfs_congestion_kb > 256*1024)
1957 nfs_congestion_kb = 256*1024;
1961 out_destroy_commit_cache:
1962 kmem_cache_destroy(nfs_cdata_cachep);
1963 out_destroy_write_mempool:
1964 mempool_destroy(nfs_wdata_mempool);
1965 out_destroy_write_cache:
1966 kmem_cache_destroy(nfs_wdata_cachep);
1970 void nfs_destroy_writepagecache(void)
1972 mempool_destroy(nfs_commit_mempool);
1973 kmem_cache_destroy(nfs_cdata_cachep);
1974 mempool_destroy(nfs_wdata_mempool);
1975 kmem_cache_destroy(nfs_wdata_cachep);
1978 static const struct nfs_rw_ops nfs_rw_write_ops = {
1979 .rw_mode = FMODE_WRITE,
1980 .rw_alloc_header = nfs_writehdr_alloc,
1981 .rw_free_header = nfs_writehdr_free,
1982 .rw_release = nfs_writeback_release_common,
1983 .rw_done = nfs_writeback_done,
1984 .rw_result = nfs_writeback_result,
1985 .rw_initiate = nfs_initiate_write,