2 * linux/fs/nfs/direct.c
4 * Copyright (C) 2003 by Chuck Lever <cel@netapp.com>
6 * High-performance uncached I/O for the Linux NFS client
8 * There are important applications whose performance or correctness
9 * depends on uncached access to file data. Database clusters
10 * (multiple copies of the same instance running on separate hosts)
11 * implement their own cache coherency protocol that subsumes file
12 * system cache protocols. Applications that process datasets
13 * considerably larger than the client's memory do not always benefit
14 * from a local cache. A streaming video server, for instance, has no
15 * need to cache the contents of a file.
17 * When an application requests uncached I/O, all read and write requests
18 * are made directly to the server; data stored or fetched via these
19 * requests is not cached in the Linux page cache. The client does not
20 * correct unaligned requests from applications. All requested bytes are
21 * held on permanent storage before a direct write system call returns to
24 * Solaris implements an uncached I/O facility called directio() that
25 * is used for backups and sequential I/O to very large files. Solaris
26 * also supports uncaching whole NFS partitions with "-o forcedirectio,"
27 * an undocumented mount option.
29 * Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust, with
30 * help from Andrew Morton.
32 * 18 Dec 2001 Initial implementation for 2.4 --cel
33 * 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy
34 * 08 Jun 2003 Port to 2.5 APIs --cel
35 * 31 Mar 2004 Handle direct I/O without VFS support --cel
36 * 15 Sep 2004 Parallel async reads --cel
37 * 04 May 2005 support O_DIRECT with aio --cel
41 #include <linux/errno.h>
42 #include <linux/sched.h>
43 #include <linux/kernel.h>
44 #include <linux/file.h>
45 #include <linux/pagemap.h>
46 #include <linux/kref.h>
47 #include <linux/slab.h>
48 #include <linux/task_io_accounting_ops.h>
50 #include <linux/nfs_fs.h>
51 #include <linux/nfs_page.h>
52 #include <linux/sunrpc/clnt.h>
54 #include <asm/system.h>
55 #include <asm/uaccess.h>
56 #include <linux/atomic.h>
61 #define NFSDBG_FACILITY NFSDBG_VFS
63 static struct kmem_cache
*nfs_direct_cachep
;
66 * This represents a set of asynchronous requests that we're waiting on
68 struct nfs_direct_req
{
69 struct kref kref
; /* release manager */
72 struct nfs_open_context
*ctx
; /* file open context info */
73 struct nfs_lock_context
*l_ctx
; /* Lock context info */
74 struct kiocb
* iocb
; /* controlling i/o request */
75 struct inode
* inode
; /* target file of i/o */
77 /* completion state */
78 atomic_t io_count
; /* i/os we're waiting for */
79 spinlock_t lock
; /* protect completion state */
80 ssize_t count
, /* bytes actually processed */
81 error
; /* any reported error */
82 struct completion completion
; /* wait for i/o completion */
85 struct list_head rewrite_list
; /* saved nfs_write_data structs */
86 struct nfs_write_data
* commit_data
; /* special write_data for commits */
88 #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */
89 #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */
90 struct nfs_writeverf verf
; /* unstable write verifier */
93 static void nfs_direct_write_complete(struct nfs_direct_req
*dreq
, struct inode
*inode
);
94 static const struct rpc_call_ops nfs_write_direct_ops
;
96 static inline void get_dreq(struct nfs_direct_req
*dreq
)
98 atomic_inc(&dreq
->io_count
);
101 static inline int put_dreq(struct nfs_direct_req
*dreq
)
103 return atomic_dec_and_test(&dreq
->io_count
);
107 * nfs_direct_IO - NFS address space operation for direct I/O
108 * @rw: direction (read or write)
109 * @iocb: target I/O control block
110 * @iov: array of vectors that define I/O buffer
111 * @pos: offset in file to begin the operation
112 * @nr_segs: size of iovec array
114 * The presence of this routine in the address space ops vector means
115 * the NFS client supports direct I/O. However, we shunt off direct
116 * read and write requests before the VFS gets them, so this method
117 * should never be called.
119 ssize_t
nfs_direct_IO(int rw
, struct kiocb
*iocb
, const struct iovec
*iov
, loff_t pos
, unsigned long nr_segs
)
121 dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
122 iocb
->ki_filp
->f_path
.dentry
->d_name
.name
,
123 (long long) pos
, nr_segs
);
128 static void nfs_direct_dirty_pages(struct page
**pages
, unsigned int pgbase
, size_t count
)
135 pages
+= (pgbase
>> PAGE_SHIFT
);
136 npages
= (count
+ (pgbase
& ~PAGE_MASK
) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
137 for (i
= 0; i
< npages
; i
++) {
138 struct page
*page
= pages
[i
];
139 if (!PageCompound(page
))
140 set_page_dirty(page
);
144 static void nfs_direct_release_pages(struct page
**pages
, unsigned int npages
)
147 for (i
= 0; i
< npages
; i
++)
148 page_cache_release(pages
[i
]);
151 static inline struct nfs_direct_req
*nfs_direct_req_alloc(void)
153 struct nfs_direct_req
*dreq
;
155 dreq
= kmem_cache_alloc(nfs_direct_cachep
, GFP_KERNEL
);
159 kref_init(&dreq
->kref
);
160 kref_get(&dreq
->kref
);
161 init_completion(&dreq
->completion
);
162 INIT_LIST_HEAD(&dreq
->rewrite_list
);
166 spin_lock_init(&dreq
->lock
);
167 atomic_set(&dreq
->io_count
, 0);
175 static void nfs_direct_req_free(struct kref
*kref
)
177 struct nfs_direct_req
*dreq
= container_of(kref
, struct nfs_direct_req
, kref
);
179 if (dreq
->l_ctx
!= NULL
)
180 nfs_put_lock_context(dreq
->l_ctx
);
181 if (dreq
->ctx
!= NULL
)
182 put_nfs_open_context(dreq
->ctx
);
183 kmem_cache_free(nfs_direct_cachep
, dreq
);
186 static void nfs_direct_req_release(struct nfs_direct_req
*dreq
)
188 kref_put(&dreq
->kref
, nfs_direct_req_free
);
192 * Collects and returns the final error value/byte-count.
194 static ssize_t
nfs_direct_wait(struct nfs_direct_req
*dreq
)
196 ssize_t result
= -EIOCBQUEUED
;
198 /* Async requests don't wait here */
202 result
= wait_for_completion_killable(&dreq
->completion
);
205 result
= dreq
->error
;
207 result
= dreq
->count
;
210 return (ssize_t
) result
;
214 * Synchronous I/O uses a stack-allocated iocb. Thus we can't trust
215 * the iocb is still valid here if this is a synchronous request.
217 static void nfs_direct_complete(struct nfs_direct_req
*dreq
)
220 long res
= (long) dreq
->error
;
222 res
= (long) dreq
->count
;
223 aio_complete(dreq
->iocb
, res
, 0);
225 complete_all(&dreq
->completion
);
227 nfs_direct_req_release(dreq
);
231 * We must hold a reference to all the pages in this direct read request
232 * until the RPCs complete. This could be long *after* we are woken up in
233 * nfs_direct_wait (for instance, if someone hits ^C on a slow server).
235 static void nfs_direct_read_result(struct rpc_task
*task
, void *calldata
)
237 struct nfs_read_data
*data
= calldata
;
239 nfs_readpage_result(task
, data
);
242 static void nfs_direct_read_release(void *calldata
)
245 struct nfs_read_data
*data
= calldata
;
246 struct nfs_direct_req
*dreq
= (struct nfs_direct_req
*) data
->req
;
247 int status
= data
->task
.tk_status
;
249 spin_lock(&dreq
->lock
);
250 if (unlikely(status
< 0)) {
251 dreq
->error
= status
;
252 spin_unlock(&dreq
->lock
);
254 dreq
->count
+= data
->res
.count
;
255 spin_unlock(&dreq
->lock
);
256 nfs_direct_dirty_pages(data
->pagevec
,
260 nfs_direct_release_pages(data
->pagevec
, data
->npages
);
263 nfs_direct_complete(dreq
);
264 nfs_readdata_free(data
);
267 static const struct rpc_call_ops nfs_read_direct_ops
= {
268 .rpc_call_prepare
= nfs_read_prepare
,
269 .rpc_call_done
= nfs_direct_read_result
,
270 .rpc_release
= nfs_direct_read_release
,
274 * For each rsize'd chunk of the user's buffer, dispatch an NFS READ
275 * operation. If nfs_readdata_alloc() or get_user_pages() fails,
276 * bail and stop sending more reads. Read length accounting is
277 * handled automatically by nfs_direct_read_result(). Otherwise, if
278 * no requests have been sent, just return an error.
280 static ssize_t
nfs_direct_read_schedule_segment(struct nfs_direct_req
*dreq
,
281 const struct iovec
*iov
,
284 struct nfs_open_context
*ctx
= dreq
->ctx
;
285 struct inode
*inode
= ctx
->dentry
->d_inode
;
286 unsigned long user_addr
= (unsigned long)iov
->iov_base
;
287 size_t count
= iov
->iov_len
;
288 size_t rsize
= NFS_SERVER(inode
)->rsize
;
289 struct rpc_task
*task
;
290 struct rpc_message msg
= {
291 .rpc_cred
= ctx
->cred
,
293 struct rpc_task_setup task_setup_data
= {
294 .rpc_client
= NFS_CLIENT(inode
),
296 .callback_ops
= &nfs_read_direct_ops
,
297 .workqueue
= nfsiod_workqueue
,
298 .flags
= RPC_TASK_ASYNC
,
305 struct nfs_read_data
*data
;
308 pgbase
= user_addr
& ~PAGE_MASK
;
309 bytes
= min(rsize
,count
);
312 data
= nfs_readdata_alloc(nfs_page_array_len(pgbase
, bytes
));
316 down_read(¤t
->mm
->mmap_sem
);
317 result
= get_user_pages(current
, current
->mm
, user_addr
,
318 data
->npages
, 1, 0, data
->pagevec
, NULL
);
319 up_read(¤t
->mm
->mmap_sem
);
321 nfs_readdata_free(data
);
324 if ((unsigned)result
< data
->npages
) {
325 bytes
= result
* PAGE_SIZE
;
326 if (bytes
<= pgbase
) {
327 nfs_direct_release_pages(data
->pagevec
, result
);
328 nfs_readdata_free(data
);
332 data
->npages
= result
;
337 data
->req
= (struct nfs_page
*) dreq
;
339 data
->cred
= msg
.rpc_cred
;
340 data
->args
.fh
= NFS_FH(inode
);
341 data
->args
.context
= ctx
;
342 data
->args
.lock_context
= dreq
->l_ctx
;
343 data
->args
.offset
= pos
;
344 data
->args
.pgbase
= pgbase
;
345 data
->args
.pages
= data
->pagevec
;
346 data
->args
.count
= bytes
;
347 data
->res
.fattr
= &data
->fattr
;
349 data
->res
.count
= bytes
;
350 nfs_fattr_init(&data
->fattr
);
351 msg
.rpc_argp
= &data
->args
;
352 msg
.rpc_resp
= &data
->res
;
354 task_setup_data
.task
= &data
->task
;
355 task_setup_data
.callback_data
= data
;
356 NFS_PROTO(inode
)->read_setup(data
, &msg
);
358 task
= rpc_run_task(&task_setup_data
);
363 dprintk("NFS: %5u initiated direct read call "
364 "(req %s/%Ld, %zu bytes @ offset %Lu)\n",
367 (long long)NFS_FILEID(inode
),
369 (unsigned long long)data
->args
.offset
);
374 /* FIXME: Remove this unnecessary math from final patch */
376 pgbase
&= ~PAGE_MASK
;
377 BUG_ON(pgbase
!= (user_addr
& ~PAGE_MASK
));
380 } while (count
!= 0);
384 return result
< 0 ? (ssize_t
) result
: -EFAULT
;
387 static ssize_t
nfs_direct_read_schedule_iovec(struct nfs_direct_req
*dreq
,
388 const struct iovec
*iov
,
389 unsigned long nr_segs
,
392 ssize_t result
= -EINVAL
;
393 size_t requested_bytes
= 0;
398 for (seg
= 0; seg
< nr_segs
; seg
++) {
399 const struct iovec
*vec
= &iov
[seg
];
400 result
= nfs_direct_read_schedule_segment(dreq
, vec
, pos
);
403 requested_bytes
+= result
;
404 if ((size_t)result
< vec
->iov_len
)
410 * If no bytes were started, return the error, and let the
411 * generic layer handle the completion.
413 if (requested_bytes
== 0) {
414 nfs_direct_req_release(dreq
);
415 return result
< 0 ? result
: -EIO
;
419 nfs_direct_complete(dreq
);
423 static ssize_t
nfs_direct_read(struct kiocb
*iocb
, const struct iovec
*iov
,
424 unsigned long nr_segs
, loff_t pos
)
426 ssize_t result
= -ENOMEM
;
427 struct inode
*inode
= iocb
->ki_filp
->f_mapping
->host
;
428 struct nfs_direct_req
*dreq
;
430 dreq
= nfs_direct_req_alloc();
435 dreq
->ctx
= get_nfs_open_context(nfs_file_open_context(iocb
->ki_filp
));
436 dreq
->l_ctx
= nfs_get_lock_context(dreq
->ctx
);
437 if (dreq
->l_ctx
== NULL
)
439 if (!is_sync_kiocb(iocb
))
442 result
= nfs_direct_read_schedule_iovec(dreq
, iov
, nr_segs
, pos
);
444 result
= nfs_direct_wait(dreq
);
446 nfs_direct_req_release(dreq
);
451 static void nfs_direct_free_writedata(struct nfs_direct_req
*dreq
)
453 while (!list_empty(&dreq
->rewrite_list
)) {
454 struct nfs_write_data
*data
= list_entry(dreq
->rewrite_list
.next
, struct nfs_write_data
, pages
);
455 list_del(&data
->pages
);
456 nfs_direct_release_pages(data
->pagevec
, data
->npages
);
457 nfs_writedata_free(data
);
461 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
462 static void nfs_direct_write_reschedule(struct nfs_direct_req
*dreq
)
464 struct inode
*inode
= dreq
->inode
;
466 struct nfs_write_data
*data
;
467 struct rpc_task
*task
;
468 struct rpc_message msg
= {
469 .rpc_cred
= dreq
->ctx
->cred
,
471 struct rpc_task_setup task_setup_data
= {
472 .rpc_client
= NFS_CLIENT(inode
),
474 .callback_ops
= &nfs_write_direct_ops
,
475 .workqueue
= nfsiod_workqueue
,
476 .flags
= RPC_TASK_ASYNC
,
482 list_for_each(p
, &dreq
->rewrite_list
) {
483 data
= list_entry(p
, struct nfs_write_data
, pages
);
487 /* Use stable writes */
488 data
->args
.stable
= NFS_FILE_SYNC
;
493 nfs_fattr_init(&data
->fattr
);
494 data
->res
.count
= data
->args
.count
;
495 memset(&data
->verf
, 0, sizeof(data
->verf
));
498 * Reuse data->task; data->args should not have changed
499 * since the original request was sent.
501 task_setup_data
.task
= &data
->task
;
502 task_setup_data
.callback_data
= data
;
503 msg
.rpc_argp
= &data
->args
;
504 msg
.rpc_resp
= &data
->res
;
505 NFS_PROTO(inode
)->write_setup(data
, &msg
);
508 * We're called via an RPC callback, so BKL is already held.
510 task
= rpc_run_task(&task_setup_data
);
514 dprintk("NFS: %5u rescheduled direct write call (req %s/%Ld, %u bytes @ offset %Lu)\n",
517 (long long)NFS_FILEID(inode
),
519 (unsigned long long)data
->args
.offset
);
523 nfs_direct_write_complete(dreq
, inode
);
526 static void nfs_direct_commit_result(struct rpc_task
*task
, void *calldata
)
528 struct nfs_write_data
*data
= calldata
;
530 /* Call the NFS version-specific code */
531 NFS_PROTO(data
->inode
)->commit_done(task
, data
);
534 static void nfs_direct_commit_release(void *calldata
)
536 struct nfs_write_data
*data
= calldata
;
537 struct nfs_direct_req
*dreq
= (struct nfs_direct_req
*) data
->req
;
538 int status
= data
->task
.tk_status
;
541 dprintk("NFS: %5u commit failed with error %d.\n",
542 data
->task
.tk_pid
, status
);
543 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
544 } else if (memcmp(&dreq
->verf
, &data
->verf
, sizeof(data
->verf
))) {
545 dprintk("NFS: %5u commit verify failed\n", data
->task
.tk_pid
);
546 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
549 dprintk("NFS: %5u commit returned %d\n", data
->task
.tk_pid
, status
);
550 nfs_direct_write_complete(dreq
, data
->inode
);
551 nfs_commit_free(data
);
554 static const struct rpc_call_ops nfs_commit_direct_ops
= {
555 .rpc_call_prepare
= nfs_write_prepare
,
556 .rpc_call_done
= nfs_direct_commit_result
,
557 .rpc_release
= nfs_direct_commit_release
,
560 static void nfs_direct_commit_schedule(struct nfs_direct_req
*dreq
)
562 struct nfs_write_data
*data
= dreq
->commit_data
;
563 struct rpc_task
*task
;
564 struct rpc_message msg
= {
565 .rpc_argp
= &data
->args
,
566 .rpc_resp
= &data
->res
,
567 .rpc_cred
= dreq
->ctx
->cred
,
569 struct rpc_task_setup task_setup_data
= {
571 .rpc_client
= NFS_CLIENT(dreq
->inode
),
573 .callback_ops
= &nfs_commit_direct_ops
,
574 .callback_data
= data
,
575 .workqueue
= nfsiod_workqueue
,
576 .flags
= RPC_TASK_ASYNC
,
579 data
->inode
= dreq
->inode
;
580 data
->cred
= msg
.rpc_cred
;
582 data
->args
.fh
= NFS_FH(data
->inode
);
583 data
->args
.offset
= 0;
584 data
->args
.count
= 0;
585 data
->args
.context
= dreq
->ctx
;
586 data
->args
.lock_context
= dreq
->l_ctx
;
588 data
->res
.fattr
= &data
->fattr
;
589 data
->res
.verf
= &data
->verf
;
590 nfs_fattr_init(&data
->fattr
);
592 NFS_PROTO(data
->inode
)->commit_setup(data
, &msg
);
594 /* Note: task.tk_ops->rpc_release will free dreq->commit_data */
595 dreq
->commit_data
= NULL
;
597 dprintk("NFS: %5u initiated commit call\n", data
->task
.tk_pid
);
599 task
= rpc_run_task(&task_setup_data
);
604 static void nfs_direct_write_complete(struct nfs_direct_req
*dreq
, struct inode
*inode
)
606 int flags
= dreq
->flags
;
610 case NFS_ODIRECT_DO_COMMIT
:
611 nfs_direct_commit_schedule(dreq
);
613 case NFS_ODIRECT_RESCHED_WRITES
:
614 nfs_direct_write_reschedule(dreq
);
617 if (dreq
->commit_data
!= NULL
)
618 nfs_commit_free(dreq
->commit_data
);
619 nfs_direct_free_writedata(dreq
);
620 nfs_zap_mapping(inode
, inode
->i_mapping
);
621 nfs_direct_complete(dreq
);
625 static void nfs_alloc_commit_data(struct nfs_direct_req
*dreq
)
627 dreq
->commit_data
= nfs_commitdata_alloc();
628 if (dreq
->commit_data
!= NULL
)
629 dreq
->commit_data
->req
= (struct nfs_page
*) dreq
;
632 static inline void nfs_alloc_commit_data(struct nfs_direct_req
*dreq
)
634 dreq
->commit_data
= NULL
;
637 static void nfs_direct_write_complete(struct nfs_direct_req
*dreq
, struct inode
*inode
)
639 nfs_direct_free_writedata(dreq
);
640 nfs_zap_mapping(inode
, inode
->i_mapping
);
641 nfs_direct_complete(dreq
);
645 static void nfs_direct_write_result(struct rpc_task
*task
, void *calldata
)
647 struct nfs_write_data
*data
= calldata
;
649 nfs_writeback_done(task
, data
);
653 * NB: Return the value of the first error return code. Subsequent
654 * errors after the first one are ignored.
656 static void nfs_direct_write_release(void *calldata
)
658 struct nfs_write_data
*data
= calldata
;
659 struct nfs_direct_req
*dreq
= (struct nfs_direct_req
*) data
->req
;
660 int status
= data
->task
.tk_status
;
662 spin_lock(&dreq
->lock
);
664 if (unlikely(status
< 0)) {
665 /* An error has occurred, so we should not commit */
667 dreq
->error
= status
;
669 if (unlikely(dreq
->error
!= 0))
672 dreq
->count
+= data
->res
.count
;
674 if (data
->res
.verf
->committed
!= NFS_FILE_SYNC
) {
675 switch (dreq
->flags
) {
677 memcpy(&dreq
->verf
, &data
->verf
, sizeof(dreq
->verf
));
678 dreq
->flags
= NFS_ODIRECT_DO_COMMIT
;
680 case NFS_ODIRECT_DO_COMMIT
:
681 if (memcmp(&dreq
->verf
, &data
->verf
, sizeof(dreq
->verf
))) {
682 dprintk("NFS: %5u write verify failed\n", data
->task
.tk_pid
);
683 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
688 spin_unlock(&dreq
->lock
);
691 nfs_direct_write_complete(dreq
, data
->inode
);
694 static const struct rpc_call_ops nfs_write_direct_ops
= {
695 .rpc_call_prepare
= nfs_write_prepare
,
696 .rpc_call_done
= nfs_direct_write_result
,
697 .rpc_release
= nfs_direct_write_release
,
701 * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE
702 * operation. If nfs_writedata_alloc() or get_user_pages() fails,
703 * bail and stop sending more writes. Write length accounting is
704 * handled automatically by nfs_direct_write_result(). Otherwise, if
705 * no requests have been sent, just return an error.
707 static ssize_t
nfs_direct_write_schedule_segment(struct nfs_direct_req
*dreq
,
708 const struct iovec
*iov
,
709 loff_t pos
, int sync
)
711 struct nfs_open_context
*ctx
= dreq
->ctx
;
712 struct inode
*inode
= ctx
->dentry
->d_inode
;
713 unsigned long user_addr
= (unsigned long)iov
->iov_base
;
714 size_t count
= iov
->iov_len
;
715 struct rpc_task
*task
;
716 struct rpc_message msg
= {
717 .rpc_cred
= ctx
->cred
,
719 struct rpc_task_setup task_setup_data
= {
720 .rpc_client
= NFS_CLIENT(inode
),
722 .callback_ops
= &nfs_write_direct_ops
,
723 .workqueue
= nfsiod_workqueue
,
724 .flags
= RPC_TASK_ASYNC
,
726 size_t wsize
= NFS_SERVER(inode
)->wsize
;
732 struct nfs_write_data
*data
;
735 pgbase
= user_addr
& ~PAGE_MASK
;
736 bytes
= min(wsize
,count
);
739 data
= nfs_writedata_alloc(nfs_page_array_len(pgbase
, bytes
));
743 down_read(¤t
->mm
->mmap_sem
);
744 result
= get_user_pages(current
, current
->mm
, user_addr
,
745 data
->npages
, 0, 0, data
->pagevec
, NULL
);
746 up_read(¤t
->mm
->mmap_sem
);
748 nfs_writedata_free(data
);
751 if ((unsigned)result
< data
->npages
) {
752 bytes
= result
* PAGE_SIZE
;
753 if (bytes
<= pgbase
) {
754 nfs_direct_release_pages(data
->pagevec
, result
);
755 nfs_writedata_free(data
);
759 data
->npages
= result
;
764 list_move_tail(&data
->pages
, &dreq
->rewrite_list
);
766 data
->req
= (struct nfs_page
*) dreq
;
768 data
->cred
= msg
.rpc_cred
;
769 data
->args
.fh
= NFS_FH(inode
);
770 data
->args
.context
= ctx
;
771 data
->args
.lock_context
= dreq
->l_ctx
;
772 data
->args
.offset
= pos
;
773 data
->args
.pgbase
= pgbase
;
774 data
->args
.pages
= data
->pagevec
;
775 data
->args
.count
= bytes
;
776 data
->args
.stable
= sync
;
777 data
->res
.fattr
= &data
->fattr
;
778 data
->res
.count
= bytes
;
779 data
->res
.verf
= &data
->verf
;
780 nfs_fattr_init(&data
->fattr
);
782 task_setup_data
.task
= &data
->task
;
783 task_setup_data
.callback_data
= data
;
784 msg
.rpc_argp
= &data
->args
;
785 msg
.rpc_resp
= &data
->res
;
786 NFS_PROTO(inode
)->write_setup(data
, &msg
);
788 task
= rpc_run_task(&task_setup_data
);
793 dprintk("NFS: %5u initiated direct write call "
794 "(req %s/%Ld, %zu bytes @ offset %Lu)\n",
797 (long long)NFS_FILEID(inode
),
799 (unsigned long long)data
->args
.offset
);
805 /* FIXME: Remove this useless math from the final patch */
807 pgbase
&= ~PAGE_MASK
;
808 BUG_ON(pgbase
!= (user_addr
& ~PAGE_MASK
));
811 } while (count
!= 0);
815 return result
< 0 ? (ssize_t
) result
: -EFAULT
;
818 static ssize_t
nfs_direct_write_schedule_iovec(struct nfs_direct_req
*dreq
,
819 const struct iovec
*iov
,
820 unsigned long nr_segs
,
821 loff_t pos
, int sync
)
824 size_t requested_bytes
= 0;
829 for (seg
= 0; seg
< nr_segs
; seg
++) {
830 const struct iovec
*vec
= &iov
[seg
];
831 result
= nfs_direct_write_schedule_segment(dreq
, vec
,
835 requested_bytes
+= result
;
836 if ((size_t)result
< vec
->iov_len
)
842 * If no bytes were started, return the error, and let the
843 * generic layer handle the completion.
845 if (requested_bytes
== 0) {
846 nfs_direct_req_release(dreq
);
847 return result
< 0 ? result
: -EIO
;
851 nfs_direct_write_complete(dreq
, dreq
->inode
);
855 static ssize_t
nfs_direct_write(struct kiocb
*iocb
, const struct iovec
*iov
,
856 unsigned long nr_segs
, loff_t pos
,
859 ssize_t result
= -ENOMEM
;
860 struct inode
*inode
= iocb
->ki_filp
->f_mapping
->host
;
861 struct nfs_direct_req
*dreq
;
862 size_t wsize
= NFS_SERVER(inode
)->wsize
;
863 int sync
= NFS_UNSTABLE
;
865 dreq
= nfs_direct_req_alloc();
868 nfs_alloc_commit_data(dreq
);
870 if (dreq
->commit_data
== NULL
|| count
<= wsize
)
871 sync
= NFS_FILE_SYNC
;
874 dreq
->ctx
= get_nfs_open_context(nfs_file_open_context(iocb
->ki_filp
));
875 dreq
->l_ctx
= nfs_get_lock_context(dreq
->ctx
);
876 if (dreq
->l_ctx
== NULL
)
878 if (!is_sync_kiocb(iocb
))
881 result
= nfs_direct_write_schedule_iovec(dreq
, iov
, nr_segs
, pos
, sync
);
883 result
= nfs_direct_wait(dreq
);
885 nfs_direct_req_release(dreq
);
891 * nfs_file_direct_read - file direct read operation for NFS files
892 * @iocb: target I/O control block
893 * @iov: vector of user buffers into which to read data
894 * @nr_segs: size of iov vector
895 * @pos: byte offset in file where reading starts
897 * We use this function for direct reads instead of calling
898 * generic_file_aio_read() in order to avoid gfar's check to see if
899 * the request starts before the end of the file. For that check
900 * to work, we must generate a GETATTR before each direct read, and
901 * even then there is a window between the GETATTR and the subsequent
902 * READ where the file size could change. Our preference is simply
903 * to do all reads the application wants, and the server will take
904 * care of managing the end of file boundary.
906 * This function also eliminates unnecessarily updating the file's
907 * atime locally, as the NFS server sets the file's atime, and this
908 * client must read the updated atime from the server back into its
911 ssize_t
nfs_file_direct_read(struct kiocb
*iocb
, const struct iovec
*iov
,
912 unsigned long nr_segs
, loff_t pos
)
914 ssize_t retval
= -EINVAL
;
915 struct file
*file
= iocb
->ki_filp
;
916 struct address_space
*mapping
= file
->f_mapping
;
919 count
= iov_length(iov
, nr_segs
);
920 nfs_add_stats(mapping
->host
, NFSIOS_DIRECTREADBYTES
, count
);
922 dfprintk(FILE, "NFS: direct read(%s/%s, %zd@%Ld)\n",
923 file
->f_path
.dentry
->d_parent
->d_name
.name
,
924 file
->f_path
.dentry
->d_name
.name
,
925 count
, (long long) pos
);
931 retval
= nfs_sync_mapping(mapping
);
935 task_io_account_read(count
);
937 retval
= nfs_direct_read(iocb
, iov
, nr_segs
, pos
);
939 iocb
->ki_pos
= pos
+ retval
;
946 * nfs_file_direct_write - file direct write operation for NFS files
947 * @iocb: target I/O control block
948 * @iov: vector of user buffers from which to write data
949 * @nr_segs: size of iov vector
950 * @pos: byte offset in file where writing starts
952 * We use this function for direct writes instead of calling
953 * generic_file_aio_write() in order to avoid taking the inode
954 * semaphore and updating the i_size. The NFS server will set
955 * the new i_size and this client must read the updated size
956 * back into its cache. We let the server do generic write
957 * parameter checking and report problems.
959 * We eliminate local atime updates, see direct read above.
961 * We avoid unnecessary page cache invalidations for normal cached
962 * readers of this file.
964 * Note that O_APPEND is not supported for NFS direct writes, as there
965 * is no atomic O_APPEND write facility in the NFS protocol.
967 ssize_t
nfs_file_direct_write(struct kiocb
*iocb
, const struct iovec
*iov
,
968 unsigned long nr_segs
, loff_t pos
)
970 ssize_t retval
= -EINVAL
;
971 struct file
*file
= iocb
->ki_filp
;
972 struct address_space
*mapping
= file
->f_mapping
;
975 count
= iov_length(iov
, nr_segs
);
976 nfs_add_stats(mapping
->host
, NFSIOS_DIRECTWRITTENBYTES
, count
);
978 dfprintk(FILE, "NFS: direct write(%s/%s, %zd@%Ld)\n",
979 file
->f_path
.dentry
->d_parent
->d_name
.name
,
980 file
->f_path
.dentry
->d_name
.name
,
981 count
, (long long) pos
);
983 retval
= generic_write_checks(file
, &pos
, &count
, 0);
988 if ((ssize_t
) count
< 0)
994 retval
= nfs_sync_mapping(mapping
);
998 task_io_account_write(count
);
1000 retval
= nfs_direct_write(iocb
, iov
, nr_segs
, pos
, count
);
1003 iocb
->ki_pos
= pos
+ retval
;
1010 * nfs_init_directcache - create a slab cache for nfs_direct_req structures
1013 int __init
nfs_init_directcache(void)
1015 nfs_direct_cachep
= kmem_cache_create("nfs_direct_cache",
1016 sizeof(struct nfs_direct_req
),
1017 0, (SLAB_RECLAIM_ACCOUNT
|
1020 if (nfs_direct_cachep
== NULL
)
1027 * nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures
1030 void nfs_destroy_directcache(void)
1032 kmem_cache_destroy(nfs_direct_cachep
);