4 * Writing file data over NFS.
6 * We do it like this: When a (user) process wishes to write data to an
7 * NFS file, a write request is allocated that contains the RPC task data
8 * plus some info on the page to be written, and added to the inode's
9 * write chain. If the process writes past the end of the page, an async
10 * RPC call to write the page is scheduled immediately; otherwise, the call
11 * is delayed for a few seconds.
13 * Just like readahead, no async I/O is performed if wsize < PAGE_SIZE.
15 * Write requests are kept on the inode's writeback list. Each entry in
16 * that list references the page (portion) to be written. When the
17 * cache timeout has expired, the RPC task is woken up, and tries to
18 * lock the page. As soon as it manages to do so, the request is moved
19 * from the writeback list to the writelock list.
21 * Note: we must make sure never to confuse the inode passed in the
22 * write_page request with the one in page->inode. As far as I understand
23 * it, these are different when doing a swap-out.
25 * To understand everything that goes on here and in the NFS read code,
26 * one should be aware that a page is locked in exactly one of the following
29 * - A write request is in progress.
30 * - A user process is in generic_file_write/nfs_update_page
31 * - A user process is in generic_file_read
33 * Also note that because of the way pages are invalidated in
34 * nfs_revalidate_inode, the following assertions hold:
36 * - If a page is dirty, there will be no read requests (a page will
37 * not be re-read unless invalidated by nfs_revalidate_inode).
38 * - If the page is not uptodate, there will be no pending write
39 * requests, and no process will be in nfs_update_page.
41 * FIXME: Interaction with the vmscan routines is not optimal yet.
42 * Either vmscan must be made nfs-savvy, or we need a different page
43 * reclaim concept that supports something like FS-independent
44 * buffer_heads with a b_ops-> field.
46 * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
49 #include <linux/types.h>
50 #include <linux/slab.h>
52 #include <linux/pagemap.h>
53 #include <linux/file.h>
54 #include <linux/mpage.h>
55 #include <linux/writeback.h>
57 #include <linux/sunrpc/clnt.h>
58 #include <linux/nfs_fs.h>
59 #include <linux/nfs_mount.h>
60 #include <linux/nfs_page.h>
61 #include <asm/uaccess.h>
62 #include <linux/smp_lock.h>
64 #include "delegation.h"
67 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
69 #define MIN_POOL_WRITE (32)
70 #define MIN_POOL_COMMIT (4)
73 * Local function declarations
75 static struct nfs_page
* nfs_update_request(struct nfs_open_context
*,
78 unsigned int, unsigned int);
79 static int nfs_wait_on_write_congestion(struct address_space
*, int);
80 static int nfs_wait_on_requests(struct inode
*, unsigned long, unsigned int);
81 static int nfs_flush_inode(struct inode
*inode
, unsigned long idx_start
,
82 unsigned int npages
, int how
);
83 static const struct rpc_call_ops nfs_write_partial_ops
;
84 static const struct rpc_call_ops nfs_write_full_ops
;
85 static const struct rpc_call_ops nfs_commit_ops
;
87 static kmem_cache_t
*nfs_wdata_cachep
;
88 static mempool_t
*nfs_wdata_mempool
;
89 static mempool_t
*nfs_commit_mempool
;
91 static DECLARE_WAIT_QUEUE_HEAD(nfs_write_congestion
);
93 struct nfs_write_data
*nfs_commit_alloc(unsigned int pagecount
)
95 struct nfs_write_data
*p
= mempool_alloc(nfs_commit_mempool
, SLAB_NOFS
);
98 memset(p
, 0, sizeof(*p
));
99 INIT_LIST_HEAD(&p
->pages
);
100 if (pagecount
<= ARRAY_SIZE(p
->page_array
))
101 p
->pagevec
= p
->page_array
;
103 p
->pagevec
= kcalloc(pagecount
, sizeof(struct page
*), GFP_NOFS
);
105 mempool_free(p
, nfs_commit_mempool
);
113 void nfs_commit_free(struct nfs_write_data
*p
)
115 if (p
&& (p
->pagevec
!= &p
->page_array
[0]))
117 mempool_free(p
, nfs_commit_mempool
);
120 struct nfs_write_data
*nfs_writedata_alloc(unsigned int pagecount
)
122 struct nfs_write_data
*p
= mempool_alloc(nfs_wdata_mempool
, SLAB_NOFS
);
125 memset(p
, 0, sizeof(*p
));
126 INIT_LIST_HEAD(&p
->pages
);
127 if (pagecount
<= ARRAY_SIZE(p
->page_array
))
128 p
->pagevec
= p
->page_array
;
130 p
->pagevec
= kcalloc(pagecount
, sizeof(struct page
*), GFP_NOFS
);
132 mempool_free(p
, nfs_wdata_mempool
);
140 void nfs_writedata_free(struct nfs_write_data
*p
)
142 if (p
&& (p
->pagevec
!= &p
->page_array
[0]))
144 mempool_free(p
, nfs_wdata_mempool
);
147 void nfs_writedata_release(void *wdata
)
149 nfs_writedata_free(wdata
);
152 /* Adjust the file length if we're writing beyond the end */
153 static void nfs_grow_file(struct page
*page
, unsigned int offset
, unsigned int count
)
155 struct inode
*inode
= page
->mapping
->host
;
156 loff_t end
, i_size
= i_size_read(inode
);
157 unsigned long end_index
= (i_size
- 1) >> PAGE_CACHE_SHIFT
;
159 if (i_size
> 0 && page
->index
< end_index
)
161 end
= ((loff_t
)page
->index
<< PAGE_CACHE_SHIFT
) + ((loff_t
)offset
+count
);
164 nfs_inc_stats(inode
, NFSIOS_EXTENDWRITE
);
165 i_size_write(inode
, end
);
168 /* We can set the PG_uptodate flag if we see that a write request
169 * covers the full page.
171 static void nfs_mark_uptodate(struct page
*page
, unsigned int base
, unsigned int count
)
175 if (PageUptodate(page
))
179 if (count
== PAGE_CACHE_SIZE
) {
180 SetPageUptodate(page
);
184 end_offs
= i_size_read(page
->mapping
->host
) - 1;
187 /* Is this the last page? */
188 if (page
->index
!= (unsigned long)(end_offs
>> PAGE_CACHE_SHIFT
))
190 /* This is the last page: set PG_uptodate if we cover the entire
191 * extent of the data, then zero the rest of the page.
193 if (count
== (unsigned int)(end_offs
& (PAGE_CACHE_SIZE
- 1)) + 1) {
194 memclear_highpage_flush(page
, count
, PAGE_CACHE_SIZE
- count
);
195 SetPageUptodate(page
);
200 * Write a page synchronously.
201 * Offset is the data offset within the page.
203 static int nfs_writepage_sync(struct nfs_open_context
*ctx
, struct inode
*inode
,
204 struct page
*page
, unsigned int offset
, unsigned int count
,
207 unsigned int wsize
= NFS_SERVER(inode
)->wsize
;
208 int result
, written
= 0;
209 struct nfs_write_data
*wdata
;
211 wdata
= nfs_writedata_alloc(1);
216 wdata
->cred
= ctx
->cred
;
217 wdata
->inode
= inode
;
218 wdata
->args
.fh
= NFS_FH(inode
);
219 wdata
->args
.context
= ctx
;
220 wdata
->args
.pages
= &page
;
221 wdata
->args
.stable
= NFS_FILE_SYNC
;
222 wdata
->args
.pgbase
= offset
;
223 wdata
->args
.count
= wsize
;
224 wdata
->res
.fattr
= &wdata
->fattr
;
225 wdata
->res
.verf
= &wdata
->verf
;
227 dprintk("NFS: nfs_writepage_sync(%s/%Ld %d@%Ld)\n",
229 (long long)NFS_FILEID(inode
),
230 count
, (long long)(page_offset(page
) + offset
));
232 set_page_writeback(page
);
233 nfs_begin_data_update(inode
);
236 wdata
->args
.count
= count
;
237 wdata
->args
.offset
= page_offset(page
) + wdata
->args
.pgbase
;
239 result
= NFS_PROTO(inode
)->write(wdata
);
242 /* Must mark the page invalid after I/O error */
243 ClearPageUptodate(page
);
246 if (result
< wdata
->args
.count
)
247 printk(KERN_WARNING
"NFS: short write, count=%u, result=%d\n",
248 wdata
->args
.count
, result
);
250 wdata
->args
.offset
+= result
;
251 wdata
->args
.pgbase
+= result
;
254 nfs_add_stats(inode
, NFSIOS_SERVERWRITTENBYTES
, result
);
256 /* Update file length */
257 nfs_grow_file(page
, offset
, written
);
258 /* Set the PG_uptodate flag? */
259 nfs_mark_uptodate(page
, offset
, written
);
262 ClearPageError(page
);
265 nfs_end_data_update(inode
);
266 end_page_writeback(page
);
267 nfs_writedata_free(wdata
);
268 return written
? written
: result
;
271 static int nfs_writepage_async(struct nfs_open_context
*ctx
,
272 struct inode
*inode
, struct page
*page
,
273 unsigned int offset
, unsigned int count
)
275 struct nfs_page
*req
;
277 req
= nfs_update_request(ctx
, inode
, page
, offset
, count
);
280 /* Update file length */
281 nfs_grow_file(page
, offset
, count
);
282 /* Set the PG_uptodate flag? */
283 nfs_mark_uptodate(page
, offset
, count
);
284 nfs_unlock_request(req
);
288 static int wb_priority(struct writeback_control
*wbc
)
290 if (wbc
->for_reclaim
)
291 return FLUSH_HIGHPRI
;
292 if (wbc
->for_kupdate
)
298 * Write an mmapped page to the server.
300 int nfs_writepage(struct page
*page
, struct writeback_control
*wbc
)
302 struct nfs_open_context
*ctx
;
303 struct inode
*inode
= page
->mapping
->host
;
304 unsigned long end_index
;
305 unsigned offset
= PAGE_CACHE_SIZE
;
306 loff_t i_size
= i_size_read(inode
);
307 int inode_referenced
= 0;
308 int priority
= wb_priority(wbc
);
311 nfs_inc_stats(inode
, NFSIOS_VFSWRITEPAGE
);
312 nfs_add_stats(inode
, NFSIOS_WRITEPAGES
, 1);
315 * Note: We need to ensure that we have a reference to the inode
316 * if we are to do asynchronous writes. If not, waiting
317 * in nfs_wait_on_request() may deadlock with clear_inode().
319 * If igrab() fails here, then it is in any case safe to
320 * call nfs_wb_page(), since there will be no pending writes.
322 if (igrab(inode
) != 0)
323 inode_referenced
= 1;
324 end_index
= i_size
>> PAGE_CACHE_SHIFT
;
326 /* Ensure we've flushed out any previous writes */
327 nfs_wb_page_priority(inode
, page
, priority
);
330 if (page
->index
< end_index
)
332 /* things got complicated... */
333 offset
= i_size
& (PAGE_CACHE_SIZE
-1);
335 /* OK, are we completely out? */
336 err
= 0; /* potential race with truncate - ignore */
337 if (page
->index
>= end_index
+1 || !offset
)
340 ctx
= nfs_find_open_context(inode
, NULL
, FMODE_WRITE
);
346 if (!IS_SYNC(inode
) && inode_referenced
) {
347 err
= nfs_writepage_async(ctx
, inode
, page
, 0, offset
);
348 if (!wbc
->for_writepages
)
349 nfs_flush_inode(inode
, 0, 0, wb_priority(wbc
));
351 err
= nfs_writepage_sync(ctx
, inode
, page
, 0,
355 redirty_page_for_writepage(wbc
, page
);
360 put_nfs_open_context(ctx
);
363 if (inode_referenced
)
369 * Note: causes nfs_update_request() to block on the assumption
370 * that the writeback is generated due to memory pressure.
372 int nfs_writepages(struct address_space
*mapping
, struct writeback_control
*wbc
)
374 struct backing_dev_info
*bdi
= mapping
->backing_dev_info
;
375 struct inode
*inode
= mapping
->host
;
378 nfs_inc_stats(inode
, NFSIOS_VFSWRITEPAGES
);
380 err
= generic_writepages(mapping
, wbc
);
383 while (test_and_set_bit(BDI_write_congested
, &bdi
->state
) != 0) {
384 if (wbc
->nonblocking
)
386 nfs_wait_on_write_congestion(mapping
, 0);
388 err
= nfs_flush_inode(inode
, 0, 0, wb_priority(wbc
));
391 nfs_add_stats(inode
, NFSIOS_WRITEPAGES
, err
);
392 wbc
->nr_to_write
-= err
;
393 if (!wbc
->nonblocking
&& wbc
->sync_mode
== WB_SYNC_ALL
) {
394 err
= nfs_wait_on_requests(inode
, 0, 0);
398 err
= nfs_commit_inode(inode
, wb_priority(wbc
));
400 wbc
->nr_to_write
-= err
;
404 clear_bit(BDI_write_congested
, &bdi
->state
);
405 wake_up_all(&nfs_write_congestion
);
410 * Insert a write request into an inode
412 static int nfs_inode_add_request(struct inode
*inode
, struct nfs_page
*req
)
414 struct nfs_inode
*nfsi
= NFS_I(inode
);
417 error
= radix_tree_insert(&nfsi
->nfs_page_tree
, req
->wb_index
, req
);
418 BUG_ON(error
== -EEXIST
);
423 nfs_begin_data_update(inode
);
424 if (nfs_have_delegation(inode
, FMODE_WRITE
))
427 SetPagePrivate(req
->wb_page
);
429 atomic_inc(&req
->wb_count
);
434 * Insert a write request into an inode
436 static void nfs_inode_remove_request(struct nfs_page
*req
)
438 struct inode
*inode
= req
->wb_context
->dentry
->d_inode
;
439 struct nfs_inode
*nfsi
= NFS_I(inode
);
441 BUG_ON (!NFS_WBACK_BUSY(req
));
443 spin_lock(&nfsi
->req_lock
);
444 ClearPagePrivate(req
->wb_page
);
445 radix_tree_delete(&nfsi
->nfs_page_tree
, req
->wb_index
);
448 spin_unlock(&nfsi
->req_lock
);
449 nfs_end_data_update(inode
);
452 spin_unlock(&nfsi
->req_lock
);
453 nfs_clear_request(req
);
454 nfs_release_request(req
);
460 static inline struct nfs_page
*
461 _nfs_find_request(struct inode
*inode
, unsigned long index
)
463 struct nfs_inode
*nfsi
= NFS_I(inode
);
464 struct nfs_page
*req
;
466 req
= (struct nfs_page
*)radix_tree_lookup(&nfsi
->nfs_page_tree
, index
);
468 atomic_inc(&req
->wb_count
);
472 static struct nfs_page
*
473 nfs_find_request(struct inode
*inode
, unsigned long index
)
475 struct nfs_page
*req
;
476 struct nfs_inode
*nfsi
= NFS_I(inode
);
478 spin_lock(&nfsi
->req_lock
);
479 req
= _nfs_find_request(inode
, index
);
480 spin_unlock(&nfsi
->req_lock
);
485 * Add a request to the inode's dirty list.
488 nfs_mark_request_dirty(struct nfs_page
*req
)
490 struct inode
*inode
= req
->wb_context
->dentry
->d_inode
;
491 struct nfs_inode
*nfsi
= NFS_I(inode
);
493 spin_lock(&nfsi
->req_lock
);
494 radix_tree_tag_set(&nfsi
->nfs_page_tree
,
495 req
->wb_index
, NFS_PAGE_TAG_DIRTY
);
496 nfs_list_add_request(req
, &nfsi
->dirty
);
498 spin_unlock(&nfsi
->req_lock
);
499 inc_zone_page_state(req
->wb_page
, NR_FILE_DIRTY
);
500 mark_inode_dirty(inode
);
504 * Check if a request is dirty
507 nfs_dirty_request(struct nfs_page
*req
)
509 struct nfs_inode
*nfsi
= NFS_I(req
->wb_context
->dentry
->d_inode
);
510 return !list_empty(&req
->wb_list
) && req
->wb_list_head
== &nfsi
->dirty
;
513 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
515 * Add a request to the inode's commit list.
518 nfs_mark_request_commit(struct nfs_page
*req
)
520 struct inode
*inode
= req
->wb_context
->dentry
->d_inode
;
521 struct nfs_inode
*nfsi
= NFS_I(inode
);
523 spin_lock(&nfsi
->req_lock
);
524 nfs_list_add_request(req
, &nfsi
->commit
);
526 spin_unlock(&nfsi
->req_lock
);
527 inc_zone_page_state(req
->wb_page
, NR_UNSTABLE_NFS
);
528 mark_inode_dirty(inode
);
533 * Wait for a request to complete.
535 * Interruptible by signals only if mounted with intr flag.
537 static int nfs_wait_on_requests_locked(struct inode
*inode
, unsigned long idx_start
, unsigned int npages
)
539 struct nfs_inode
*nfsi
= NFS_I(inode
);
540 struct nfs_page
*req
;
541 unsigned long idx_end
, next
;
542 unsigned int res
= 0;
548 idx_end
= idx_start
+ npages
- 1;
551 while (radix_tree_gang_lookup_tag(&nfsi
->nfs_page_tree
, (void **)&req
, next
, 1, NFS_PAGE_TAG_WRITEBACK
)) {
552 if (req
->wb_index
> idx_end
)
555 next
= req
->wb_index
+ 1;
556 BUG_ON(!NFS_WBACK_BUSY(req
));
558 atomic_inc(&req
->wb_count
);
559 spin_unlock(&nfsi
->req_lock
);
560 error
= nfs_wait_on_request(req
);
561 nfs_release_request(req
);
562 spin_lock(&nfsi
->req_lock
);
570 static int nfs_wait_on_requests(struct inode
*inode
, unsigned long idx_start
, unsigned int npages
)
572 struct nfs_inode
*nfsi
= NFS_I(inode
);
575 spin_lock(&nfsi
->req_lock
);
576 ret
= nfs_wait_on_requests_locked(inode
, idx_start
, npages
);
577 spin_unlock(&nfsi
->req_lock
);
581 static void nfs_cancel_requests(struct list_head
*head
)
583 struct nfs_page
*req
;
584 while(!list_empty(head
)) {
585 req
= nfs_list_entry(head
->next
);
586 nfs_list_remove_request(req
);
587 nfs_inode_remove_request(req
);
588 nfs_clear_page_writeback(req
);
593 * nfs_scan_dirty - Scan an inode for dirty requests
594 * @inode: NFS inode to scan
595 * @dst: destination list
596 * @idx_start: lower bound of page->index to scan.
597 * @npages: idx_start + npages sets the upper bound to scan.
599 * Moves requests from the inode's dirty page list.
600 * The requests are *not* checked to ensure that they form a contiguous set.
603 nfs_scan_dirty(struct inode
*inode
, struct list_head
*dst
, unsigned long idx_start
, unsigned int npages
)
605 struct nfs_inode
*nfsi
= NFS_I(inode
);
608 if (nfsi
->ndirty
!= 0) {
609 res
= nfs_scan_lock_dirty(nfsi
, dst
, idx_start
, npages
);
611 if ((nfsi
->ndirty
== 0) != list_empty(&nfsi
->dirty
))
612 printk(KERN_ERR
"NFS: desynchronized value of nfs_i.ndirty.\n");
617 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
619 * nfs_scan_commit - Scan an inode for commit requests
620 * @inode: NFS inode to scan
621 * @dst: destination list
622 * @idx_start: lower bound of page->index to scan.
623 * @npages: idx_start + npages sets the upper bound to scan.
625 * Moves requests from the inode's 'commit' request list.
626 * The requests are *not* checked to ensure that they form a contiguous set.
629 nfs_scan_commit(struct inode
*inode
, struct list_head
*dst
, unsigned long idx_start
, unsigned int npages
)
631 struct nfs_inode
*nfsi
= NFS_I(inode
);
634 if (nfsi
->ncommit
!= 0) {
635 res
= nfs_scan_list(nfsi
, &nfsi
->commit
, dst
, idx_start
, npages
);
636 nfsi
->ncommit
-= res
;
637 if ((nfsi
->ncommit
== 0) != list_empty(&nfsi
->commit
))
638 printk(KERN_ERR
"NFS: desynchronized value of nfs_i.ncommit.\n");
643 static inline int nfs_scan_commit(struct inode
*inode
, struct list_head
*dst
, unsigned long idx_start
, unsigned int npages
)
649 static int nfs_wait_on_write_congestion(struct address_space
*mapping
, int intr
)
651 struct backing_dev_info
*bdi
= mapping
->backing_dev_info
;
657 if (!bdi_write_congested(bdi
))
660 nfs_inc_stats(mapping
->host
, NFSIOS_CONGESTIONWAIT
);
663 struct rpc_clnt
*clnt
= NFS_CLIENT(mapping
->host
);
666 rpc_clnt_sigmask(clnt
, &oldset
);
667 prepare_to_wait(&nfs_write_congestion
, &wait
, TASK_INTERRUPTIBLE
);
668 if (bdi_write_congested(bdi
)) {
674 rpc_clnt_sigunmask(clnt
, &oldset
);
676 prepare_to_wait(&nfs_write_congestion
, &wait
, TASK_UNINTERRUPTIBLE
);
677 if (bdi_write_congested(bdi
))
680 finish_wait(&nfs_write_congestion
, &wait
);
686 * Try to update any existing write request, or create one if there is none.
687 * In order to match, the request's credentials must match those of
688 * the calling process.
690 * Note: Should always be called with the Page Lock held!
692 static struct nfs_page
* nfs_update_request(struct nfs_open_context
* ctx
,
693 struct inode
*inode
, struct page
*page
,
694 unsigned int offset
, unsigned int bytes
)
696 struct nfs_server
*server
= NFS_SERVER(inode
);
697 struct nfs_inode
*nfsi
= NFS_I(inode
);
698 struct nfs_page
*req
, *new = NULL
;
699 unsigned long rqend
, end
;
701 end
= offset
+ bytes
;
703 if (nfs_wait_on_write_congestion(page
->mapping
, server
->flags
& NFS_MOUNT_INTR
))
704 return ERR_PTR(-ERESTARTSYS
);
706 /* Loop over all inode entries and see if we find
707 * A request for the page we wish to update
709 spin_lock(&nfsi
->req_lock
);
710 req
= _nfs_find_request(inode
, page
->index
);
712 if (!nfs_lock_request_dontget(req
)) {
714 spin_unlock(&nfsi
->req_lock
);
715 error
= nfs_wait_on_request(req
);
716 nfs_release_request(req
);
719 nfs_release_request(new);
720 return ERR_PTR(error
);
724 spin_unlock(&nfsi
->req_lock
);
726 nfs_release_request(new);
732 nfs_lock_request_dontget(new);
733 error
= nfs_inode_add_request(inode
, new);
735 spin_unlock(&nfsi
->req_lock
);
736 nfs_unlock_request(new);
737 return ERR_PTR(error
);
739 spin_unlock(&nfsi
->req_lock
);
740 nfs_mark_request_dirty(new);
743 spin_unlock(&nfsi
->req_lock
);
745 new = nfs_create_request(ctx
, inode
, page
, offset
, bytes
);
750 /* We have a request for our page.
751 * If the creds don't match, or the
752 * page addresses don't match,
753 * tell the caller to wait on the conflicting
756 rqend
= req
->wb_offset
+ req
->wb_bytes
;
757 if (req
->wb_context
!= ctx
758 || req
->wb_page
!= page
759 || !nfs_dirty_request(req
)
760 || offset
> rqend
|| end
< req
->wb_offset
) {
761 nfs_unlock_request(req
);
762 return ERR_PTR(-EBUSY
);
765 /* Okay, the request matches. Update the region */
766 if (offset
< req
->wb_offset
) {
767 req
->wb_offset
= offset
;
768 req
->wb_pgbase
= offset
;
769 req
->wb_bytes
= rqend
- req
->wb_offset
;
773 req
->wb_bytes
= end
- req
->wb_offset
;
778 int nfs_flush_incompatible(struct file
*file
, struct page
*page
)
780 struct nfs_open_context
*ctx
= (struct nfs_open_context
*)file
->private_data
;
781 struct inode
*inode
= page
->mapping
->host
;
782 struct nfs_page
*req
;
785 * Look for a request corresponding to this page. If there
786 * is one, and it belongs to another file, we flush it out
787 * before we try to copy anything into the page. Do this
788 * due to the lack of an ACCESS-type call in NFSv2.
789 * Also do the same if we find a request from an existing
792 req
= nfs_find_request(inode
, page
->index
);
794 if (req
->wb_page
!= page
|| ctx
!= req
->wb_context
)
795 status
= nfs_wb_page(inode
, page
);
796 nfs_release_request(req
);
798 return (status
< 0) ? status
: 0;
802 * Update and possibly write a cached page of an NFS file.
804 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
805 * things with a page scheduled for an RPC call (e.g. invalidate it).
807 int nfs_updatepage(struct file
*file
, struct page
*page
,
808 unsigned int offset
, unsigned int count
)
810 struct nfs_open_context
*ctx
= (struct nfs_open_context
*)file
->private_data
;
811 struct inode
*inode
= page
->mapping
->host
;
812 struct nfs_page
*req
;
815 nfs_inc_stats(inode
, NFSIOS_VFSUPDATEPAGE
);
817 dprintk("NFS: nfs_updatepage(%s/%s %d@%Ld)\n",
818 file
->f_dentry
->d_parent
->d_name
.name
,
819 file
->f_dentry
->d_name
.name
, count
,
820 (long long)(page_offset(page
) +offset
));
822 if (IS_SYNC(inode
)) {
823 status
= nfs_writepage_sync(ctx
, inode
, page
, offset
, count
, 0);
825 if (offset
== 0 && status
== PAGE_CACHE_SIZE
)
826 SetPageUptodate(page
);
832 /* If we're not using byte range locks, and we know the page
833 * is entirely in cache, it may be more efficient to avoid
834 * fragmenting write requests.
836 if (PageUptodate(page
) && inode
->i_flock
== NULL
&& !(file
->f_mode
& O_SYNC
)) {
837 loff_t end_offs
= i_size_read(inode
) - 1;
838 unsigned long end_index
= end_offs
>> PAGE_CACHE_SHIFT
;
842 if (unlikely(end_offs
< 0)) {
844 } else if (page
->index
== end_index
) {
846 pglen
= (unsigned int)(end_offs
& (PAGE_CACHE_SIZE
-1)) + 1;
849 } else if (page
->index
< end_index
)
850 count
= PAGE_CACHE_SIZE
;
854 * Try to find an NFS request corresponding to this page
856 * If the existing request cannot be updated, we must flush
860 req
= nfs_update_request(ctx
, inode
, page
, offset
, count
);
861 status
= (IS_ERR(req
)) ? PTR_ERR(req
) : 0;
862 if (status
!= -EBUSY
)
864 /* Request could not be updated. Flush it out and try again */
865 status
= nfs_wb_page(inode
, page
);
866 } while (status
>= 0);
872 /* Update file length */
873 nfs_grow_file(page
, offset
, count
);
874 /* Set the PG_uptodate flag? */
875 nfs_mark_uptodate(page
, req
->wb_pgbase
, req
->wb_bytes
);
876 nfs_unlock_request(req
);
878 dprintk("NFS: nfs_updatepage returns %d (isize %Ld)\n",
879 status
, (long long)i_size_read(inode
));
881 ClearPageUptodate(page
);
885 static void nfs_writepage_release(struct nfs_page
*req
)
887 end_page_writeback(req
->wb_page
);
889 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
890 if (!PageError(req
->wb_page
)) {
891 if (NFS_NEED_RESCHED(req
)) {
892 nfs_mark_request_dirty(req
);
894 } else if (NFS_NEED_COMMIT(req
)) {
895 nfs_mark_request_commit(req
);
899 nfs_inode_remove_request(req
);
902 nfs_clear_commit(req
);
903 nfs_clear_reschedule(req
);
905 nfs_inode_remove_request(req
);
907 nfs_clear_page_writeback(req
);
910 static inline int flush_task_priority(int how
)
912 switch (how
& (FLUSH_HIGHPRI
|FLUSH_LOWPRI
)) {
914 return RPC_PRIORITY_HIGH
;
916 return RPC_PRIORITY_LOW
;
918 return RPC_PRIORITY_NORMAL
;
922 * Set up the argument/result storage required for the RPC call.
924 static void nfs_write_rpcsetup(struct nfs_page
*req
,
925 struct nfs_write_data
*data
,
926 const struct rpc_call_ops
*call_ops
,
927 unsigned int count
, unsigned int offset
,
933 /* Set up the RPC argument and reply structs
934 * NB: take care not to mess about with data->commit et al. */
937 data
->inode
= inode
= req
->wb_context
->dentry
->d_inode
;
938 data
->cred
= req
->wb_context
->cred
;
940 data
->args
.fh
= NFS_FH(inode
);
941 data
->args
.offset
= req_offset(req
) + offset
;
942 data
->args
.pgbase
= req
->wb_pgbase
+ offset
;
943 data
->args
.pages
= data
->pagevec
;
944 data
->args
.count
= count
;
945 data
->args
.context
= req
->wb_context
;
947 data
->res
.fattr
= &data
->fattr
;
948 data
->res
.count
= count
;
949 data
->res
.verf
= &data
->verf
;
950 nfs_fattr_init(&data
->fattr
);
952 /* Set up the initial task struct. */
953 flags
= (how
& FLUSH_SYNC
) ? 0 : RPC_TASK_ASYNC
;
954 rpc_init_task(&data
->task
, NFS_CLIENT(inode
), flags
, call_ops
, data
);
955 NFS_PROTO(inode
)->write_setup(data
, how
);
957 data
->task
.tk_priority
= flush_task_priority(how
);
958 data
->task
.tk_cookie
= (unsigned long)inode
;
960 dprintk("NFS: %4d initiated write call (req %s/%Ld, %u bytes @ offset %Lu)\n",
963 (long long)NFS_FILEID(inode
),
965 (unsigned long long)data
->args
.offset
);
968 static void nfs_execute_write(struct nfs_write_data
*data
)
970 struct rpc_clnt
*clnt
= NFS_CLIENT(data
->inode
);
973 rpc_clnt_sigmask(clnt
, &oldset
);
975 rpc_execute(&data
->task
);
977 rpc_clnt_sigunmask(clnt
, &oldset
);
981 * Generate multiple small requests to write out a single
982 * contiguous dirty area on one page.
984 static int nfs_flush_multi(struct inode
*inode
, struct list_head
*head
, int how
)
986 struct nfs_page
*req
= nfs_list_entry(head
->next
);
987 struct page
*page
= req
->wb_page
;
988 struct nfs_write_data
*data
;
989 unsigned int wsize
= NFS_SERVER(inode
)->wsize
;
990 unsigned int nbytes
, offset
;
994 nfs_list_remove_request(req
);
996 nbytes
= req
->wb_bytes
;
998 data
= nfs_writedata_alloc(1);
1001 list_add(&data
->pages
, &list
);
1003 if (nbytes
<= wsize
)
1007 atomic_set(&req
->wb_complete
, requests
);
1009 ClearPageError(page
);
1010 set_page_writeback(page
);
1012 nbytes
= req
->wb_bytes
;
1014 data
= list_entry(list
.next
, struct nfs_write_data
, pages
);
1015 list_del_init(&data
->pages
);
1017 data
->pagevec
[0] = page
;
1019 if (nbytes
> wsize
) {
1020 nfs_write_rpcsetup(req
, data
, &nfs_write_partial_ops
,
1021 wsize
, offset
, how
);
1025 nfs_write_rpcsetup(req
, data
, &nfs_write_partial_ops
,
1026 nbytes
, offset
, how
);
1029 nfs_execute_write(data
);
1030 } while (nbytes
!= 0);
1035 while (!list_empty(&list
)) {
1036 data
= list_entry(list
.next
, struct nfs_write_data
, pages
);
1037 list_del(&data
->pages
);
1038 nfs_writedata_free(data
);
1040 nfs_mark_request_dirty(req
);
1041 nfs_clear_page_writeback(req
);
1046 * Create an RPC task for the given write request and kick it.
1047 * The page must have been locked by the caller.
1049 * It may happen that the page we're passed is not marked dirty.
1050 * This is the case if nfs_updatepage detects a conflicting request
1051 * that has been written but not committed.
1053 static int nfs_flush_one(struct inode
*inode
, struct list_head
*head
, int how
)
1055 struct nfs_page
*req
;
1056 struct page
**pages
;
1057 struct nfs_write_data
*data
;
1060 data
= nfs_writedata_alloc(NFS_SERVER(inode
)->wpages
);
1064 pages
= data
->pagevec
;
1066 while (!list_empty(head
)) {
1067 req
= nfs_list_entry(head
->next
);
1068 nfs_list_remove_request(req
);
1069 nfs_list_add_request(req
, &data
->pages
);
1070 ClearPageError(req
->wb_page
);
1071 set_page_writeback(req
->wb_page
);
1072 *pages
++ = req
->wb_page
;
1073 count
+= req
->wb_bytes
;
1075 req
= nfs_list_entry(data
->pages
.next
);
1077 /* Set up the argument struct */
1078 nfs_write_rpcsetup(req
, data
, &nfs_write_full_ops
, count
, 0, how
);
1080 nfs_execute_write(data
);
1083 while (!list_empty(head
)) {
1084 struct nfs_page
*req
= nfs_list_entry(head
->next
);
1085 nfs_list_remove_request(req
);
1086 nfs_mark_request_dirty(req
);
1087 nfs_clear_page_writeback(req
);
1092 static int nfs_flush_list(struct inode
*inode
, struct list_head
*head
, int npages
, int how
)
1094 LIST_HEAD(one_request
);
1095 int (*flush_one
)(struct inode
*, struct list_head
*, int);
1096 struct nfs_page
*req
;
1097 int wpages
= NFS_SERVER(inode
)->wpages
;
1098 int wsize
= NFS_SERVER(inode
)->wsize
;
1101 flush_one
= nfs_flush_one
;
1102 if (wsize
< PAGE_CACHE_SIZE
)
1103 flush_one
= nfs_flush_multi
;
1104 /* For single writes, FLUSH_STABLE is more efficient */
1105 if (npages
<= wpages
&& npages
== NFS_I(inode
)->npages
1106 && nfs_list_entry(head
->next
)->wb_bytes
<= wsize
)
1107 how
|= FLUSH_STABLE
;
1110 nfs_coalesce_requests(head
, &one_request
, wpages
);
1111 req
= nfs_list_entry(one_request
.next
);
1112 error
= flush_one(inode
, &one_request
, how
);
1115 } while (!list_empty(head
));
1118 while (!list_empty(head
)) {
1119 req
= nfs_list_entry(head
->next
);
1120 nfs_list_remove_request(req
);
1121 nfs_mark_request_dirty(req
);
1122 nfs_clear_page_writeback(req
);
1128 * Handle a write reply that flushed part of a page.
1130 static void nfs_writeback_done_partial(struct rpc_task
*task
, void *calldata
)
1132 struct nfs_write_data
*data
= calldata
;
1133 struct nfs_page
*req
= data
->req
;
1134 struct page
*page
= req
->wb_page
;
1136 dprintk("NFS: write (%s/%Ld %d@%Ld)",
1137 req
->wb_context
->dentry
->d_inode
->i_sb
->s_id
,
1138 (long long)NFS_FILEID(req
->wb_context
->dentry
->d_inode
),
1140 (long long)req_offset(req
));
1142 if (nfs_writeback_done(task
, data
) != 0)
1145 if (task
->tk_status
< 0) {
1146 ClearPageUptodate(page
);
1148 req
->wb_context
->error
= task
->tk_status
;
1149 dprintk(", error = %d\n", task
->tk_status
);
1151 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1152 if (data
->verf
.committed
< NFS_FILE_SYNC
) {
1153 if (!NFS_NEED_COMMIT(req
)) {
1154 nfs_defer_commit(req
);
1155 memcpy(&req
->wb_verf
, &data
->verf
, sizeof(req
->wb_verf
));
1156 dprintk(" defer commit\n");
1157 } else if (memcmp(&req
->wb_verf
, &data
->verf
, sizeof(req
->wb_verf
))) {
1158 nfs_defer_reschedule(req
);
1159 dprintk(" server reboot detected\n");
1166 if (atomic_dec_and_test(&req
->wb_complete
))
1167 nfs_writepage_release(req
);
1170 static const struct rpc_call_ops nfs_write_partial_ops
= {
1171 .rpc_call_done
= nfs_writeback_done_partial
,
1172 .rpc_release
= nfs_writedata_release
,
1176 * Handle a write reply that flushes a whole page.
1178 * FIXME: There is an inherent race with invalidate_inode_pages and
1179 * writebacks since the page->count is kept > 1 for as long
1180 * as the page has a write request pending.
1182 static void nfs_writeback_done_full(struct rpc_task
*task
, void *calldata
)
1184 struct nfs_write_data
*data
= calldata
;
1185 struct nfs_page
*req
;
1188 if (nfs_writeback_done(task
, data
) != 0)
1191 /* Update attributes as result of writeback. */
1192 while (!list_empty(&data
->pages
)) {
1193 req
= nfs_list_entry(data
->pages
.next
);
1194 nfs_list_remove_request(req
);
1195 page
= req
->wb_page
;
1197 dprintk("NFS: write (%s/%Ld %d@%Ld)",
1198 req
->wb_context
->dentry
->d_inode
->i_sb
->s_id
,
1199 (long long)NFS_FILEID(req
->wb_context
->dentry
->d_inode
),
1201 (long long)req_offset(req
));
1203 if (task
->tk_status
< 0) {
1204 ClearPageUptodate(page
);
1206 req
->wb_context
->error
= task
->tk_status
;
1207 end_page_writeback(page
);
1208 nfs_inode_remove_request(req
);
1209 dprintk(", error = %d\n", task
->tk_status
);
1212 end_page_writeback(page
);
1214 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1215 if (data
->args
.stable
!= NFS_UNSTABLE
|| data
->verf
.committed
== NFS_FILE_SYNC
) {
1216 nfs_inode_remove_request(req
);
1220 memcpy(&req
->wb_verf
, &data
->verf
, sizeof(req
->wb_verf
));
1221 nfs_mark_request_commit(req
);
1222 dprintk(" marked for commit\n");
1224 nfs_inode_remove_request(req
);
1227 nfs_clear_page_writeback(req
);
1231 static const struct rpc_call_ops nfs_write_full_ops
= {
1232 .rpc_call_done
= nfs_writeback_done_full
,
1233 .rpc_release
= nfs_writedata_release
,
1238 * This function is called when the WRITE call is complete.
1240 int nfs_writeback_done(struct rpc_task
*task
, struct nfs_write_data
*data
)
1242 struct nfs_writeargs
*argp
= &data
->args
;
1243 struct nfs_writeres
*resp
= &data
->res
;
1246 dprintk("NFS: %4d nfs_writeback_done (status %d)\n",
1247 task
->tk_pid
, task
->tk_status
);
1249 /* Call the NFS version-specific code */
1250 status
= NFS_PROTO(data
->inode
)->write_done(task
, data
);
1253 nfs_add_stats(data
->inode
, NFSIOS_SERVERWRITTENBYTES
, resp
->count
);
1255 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1256 if (resp
->verf
->committed
< argp
->stable
&& task
->tk_status
>= 0) {
1257 /* We tried a write call, but the server did not
1258 * commit data to stable storage even though we
1260 * Note: There is a known bug in Tru64 < 5.0 in which
1261 * the server reports NFS_DATA_SYNC, but performs
1262 * NFS_FILE_SYNC. We therefore implement this checking
1263 * as a dprintk() in order to avoid filling syslog.
1265 static unsigned long complain
;
1267 if (time_before(complain
, jiffies
)) {
1268 dprintk("NFS: faulty NFS server %s:"
1269 " (committed = %d) != (stable = %d)\n",
1270 NFS_SERVER(data
->inode
)->hostname
,
1271 resp
->verf
->committed
, argp
->stable
);
1272 complain
= jiffies
+ 300 * HZ
;
1276 /* Is this a short write? */
1277 if (task
->tk_status
>= 0 && resp
->count
< argp
->count
) {
1278 static unsigned long complain
;
1280 nfs_inc_stats(data
->inode
, NFSIOS_SHORTWRITE
);
1282 /* Has the server at least made some progress? */
1283 if (resp
->count
!= 0) {
1284 /* Was this an NFSv2 write or an NFSv3 stable write? */
1285 if (resp
->verf
->committed
!= NFS_UNSTABLE
) {
1286 /* Resend from where the server left off */
1287 argp
->offset
+= resp
->count
;
1288 argp
->pgbase
+= resp
->count
;
1289 argp
->count
-= resp
->count
;
1291 /* Resend as a stable write in order to avoid
1292 * headaches in the case of a server crash.
1294 argp
->stable
= NFS_FILE_SYNC
;
1296 rpc_restart_call(task
);
1299 if (time_before(complain
, jiffies
)) {
1301 "NFS: Server wrote zero bytes, expected %u.\n",
1303 complain
= jiffies
+ 300 * HZ
;
1305 /* Can't do anything about it except throw an error. */
1306 task
->tk_status
= -EIO
;
1312 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1313 void nfs_commit_release(void *wdata
)
1315 nfs_commit_free(wdata
);
1319 * Set up the argument/result storage required for the RPC call.
1321 static void nfs_commit_rpcsetup(struct list_head
*head
,
1322 struct nfs_write_data
*data
,
1325 struct nfs_page
*first
;
1326 struct inode
*inode
;
1329 /* Set up the RPC argument and reply structs
1330 * NB: take care not to mess about with data->commit et al. */
1332 list_splice_init(head
, &data
->pages
);
1333 first
= nfs_list_entry(data
->pages
.next
);
1334 inode
= first
->wb_context
->dentry
->d_inode
;
1336 data
->inode
= inode
;
1337 data
->cred
= first
->wb_context
->cred
;
1339 data
->args
.fh
= NFS_FH(data
->inode
);
1340 /* Note: we always request a commit of the entire inode */
1341 data
->args
.offset
= 0;
1342 data
->args
.count
= 0;
1343 data
->res
.count
= 0;
1344 data
->res
.fattr
= &data
->fattr
;
1345 data
->res
.verf
= &data
->verf
;
1346 nfs_fattr_init(&data
->fattr
);
1348 /* Set up the initial task struct. */
1349 flags
= (how
& FLUSH_SYNC
) ? 0 : RPC_TASK_ASYNC
;
1350 rpc_init_task(&data
->task
, NFS_CLIENT(inode
), flags
, &nfs_commit_ops
, data
);
1351 NFS_PROTO(inode
)->commit_setup(data
, how
);
1353 data
->task
.tk_priority
= flush_task_priority(how
);
1354 data
->task
.tk_cookie
= (unsigned long)inode
;
1356 dprintk("NFS: %4d initiated commit call\n", data
->task
.tk_pid
);
1360 * Commit dirty pages
1363 nfs_commit_list(struct inode
*inode
, struct list_head
*head
, int how
)
1365 struct nfs_write_data
*data
;
1366 struct nfs_page
*req
;
1368 data
= nfs_commit_alloc(NFS_SERVER(inode
)->wpages
);
1373 /* Set up the argument struct */
1374 nfs_commit_rpcsetup(head
, data
, how
);
1376 nfs_execute_write(data
);
1379 while (!list_empty(head
)) {
1380 req
= nfs_list_entry(head
->next
);
1381 nfs_list_remove_request(req
);
1382 nfs_mark_request_commit(req
);
1383 nfs_clear_page_writeback(req
);
1389 * COMMIT call returned
1391 static void nfs_commit_done(struct rpc_task
*task
, void *calldata
)
1393 struct nfs_write_data
*data
= calldata
;
1394 struct nfs_page
*req
;
1396 dprintk("NFS: %4d nfs_commit_done (status %d)\n",
1397 task
->tk_pid
, task
->tk_status
);
1399 /* Call the NFS version-specific code */
1400 if (NFS_PROTO(data
->inode
)->commit_done(task
, data
) != 0)
1403 while (!list_empty(&data
->pages
)) {
1404 req
= nfs_list_entry(data
->pages
.next
);
1405 nfs_list_remove_request(req
);
1406 dec_zone_page_state(req
->wb_page
, NR_UNSTABLE_NFS
);
1408 dprintk("NFS: commit (%s/%Ld %d@%Ld)",
1409 req
->wb_context
->dentry
->d_inode
->i_sb
->s_id
,
1410 (long long)NFS_FILEID(req
->wb_context
->dentry
->d_inode
),
1412 (long long)req_offset(req
));
1413 if (task
->tk_status
< 0) {
1414 req
->wb_context
->error
= task
->tk_status
;
1415 nfs_inode_remove_request(req
);
1416 dprintk(", error = %d\n", task
->tk_status
);
1420 /* Okay, COMMIT succeeded, apparently. Check the verifier
1421 * returned by the server against all stored verfs. */
1422 if (!memcmp(req
->wb_verf
.verifier
, data
->verf
.verifier
, sizeof(data
->verf
.verifier
))) {
1423 /* We have a match */
1424 nfs_inode_remove_request(req
);
1428 /* We have a mismatch. Write the page again */
1429 dprintk(" mismatch\n");
1430 nfs_mark_request_dirty(req
);
1432 nfs_clear_page_writeback(req
);
1436 static const struct rpc_call_ops nfs_commit_ops
= {
1437 .rpc_call_done
= nfs_commit_done
,
1438 .rpc_release
= nfs_commit_release
,
1441 static inline int nfs_commit_list(struct inode
*inode
, struct list_head
*head
, int how
)
1447 static int nfs_flush_inode(struct inode
*inode
, unsigned long idx_start
,
1448 unsigned int npages
, int how
)
1450 struct nfs_inode
*nfsi
= NFS_I(inode
);
1454 spin_lock(&nfsi
->req_lock
);
1455 res
= nfs_scan_dirty(inode
, &head
, idx_start
, npages
);
1456 spin_unlock(&nfsi
->req_lock
);
1458 int error
= nfs_flush_list(inode
, &head
, res
, how
);
1465 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1466 int nfs_commit_inode(struct inode
*inode
, int how
)
1468 struct nfs_inode
*nfsi
= NFS_I(inode
);
1472 spin_lock(&nfsi
->req_lock
);
1473 res
= nfs_scan_commit(inode
, &head
, 0, 0);
1474 spin_unlock(&nfsi
->req_lock
);
1476 int error
= nfs_commit_list(inode
, &head
, how
);
1484 int nfs_sync_inode_wait(struct inode
*inode
, unsigned long idx_start
,
1485 unsigned int npages
, int how
)
1487 struct nfs_inode
*nfsi
= NFS_I(inode
);
1489 int nocommit
= how
& FLUSH_NOCOMMIT
;
1492 how
&= ~FLUSH_NOCOMMIT
;
1493 spin_lock(&nfsi
->req_lock
);
1495 ret
= nfs_wait_on_requests_locked(inode
, idx_start
, npages
);
1498 pages
= nfs_scan_dirty(inode
, &head
, idx_start
, npages
);
1500 spin_unlock(&nfsi
->req_lock
);
1501 if (how
& FLUSH_INVALIDATE
)
1502 nfs_cancel_requests(&head
);
1504 ret
= nfs_flush_list(inode
, &head
, pages
, how
);
1505 spin_lock(&nfsi
->req_lock
);
1510 pages
= nfs_scan_commit(inode
, &head
, idx_start
, npages
);
1513 if (how
& FLUSH_INVALIDATE
) {
1514 spin_unlock(&nfsi
->req_lock
);
1515 nfs_cancel_requests(&head
);
1516 spin_lock(&nfsi
->req_lock
);
1519 pages
+= nfs_scan_commit(inode
, &head
, 0, 0);
1520 spin_unlock(&nfsi
->req_lock
);
1521 ret
= nfs_commit_list(inode
, &head
, how
);
1522 spin_lock(&nfsi
->req_lock
);
1524 spin_unlock(&nfsi
->req_lock
);
1528 int __init
nfs_init_writepagecache(void)
1530 nfs_wdata_cachep
= kmem_cache_create("nfs_write_data",
1531 sizeof(struct nfs_write_data
),
1532 0, SLAB_HWCACHE_ALIGN
,
1534 if (nfs_wdata_cachep
== NULL
)
1537 nfs_wdata_mempool
= mempool_create_slab_pool(MIN_POOL_WRITE
,
1539 if (nfs_wdata_mempool
== NULL
)
1542 nfs_commit_mempool
= mempool_create_slab_pool(MIN_POOL_COMMIT
,
1544 if (nfs_commit_mempool
== NULL
)
1550 void nfs_destroy_writepagecache(void)
1552 mempool_destroy(nfs_commit_mempool
);
1553 mempool_destroy(nfs_wdata_mempool
);
1554 if (kmem_cache_destroy(nfs_wdata_cachep
))
1555 printk(KERN_INFO
"nfs_write_data: not all structures were freed\n");