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/uaccess.h>
55 #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 nfs_mds_commit_info mds_cinfo
; /* Storage for cinfo */
86 struct pnfs_ds_commit_info ds_cinfo
; /* Storage for cinfo */
87 struct work_struct work
;
89 #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */
90 #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */
91 struct nfs_writeverf verf
; /* unstable write verifier */
94 static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops
;
95 static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops
;
96 static void nfs_direct_write_complete(struct nfs_direct_req
*dreq
, struct inode
*inode
);
97 static void nfs_direct_write_schedule_work(struct work_struct
*work
);
99 static inline void get_dreq(struct nfs_direct_req
*dreq
)
101 atomic_inc(&dreq
->io_count
);
104 static inline int put_dreq(struct nfs_direct_req
*dreq
)
106 return atomic_dec_and_test(&dreq
->io_count
);
110 * nfs_direct_IO - NFS address space operation for direct I/O
111 * @rw: direction (read or write)
112 * @iocb: target I/O control block
113 * @iov: array of vectors that define I/O buffer
114 * @pos: offset in file to begin the operation
115 * @nr_segs: size of iovec array
117 * The presence of this routine in the address space ops vector means
118 * the NFS client supports direct I/O. However, for most direct IO, we
119 * shunt off direct read and write requests before the VFS gets them,
120 * so this method is only ever called for swap.
122 ssize_t
nfs_direct_IO(int rw
, struct kiocb
*iocb
, const struct iovec
*iov
, loff_t pos
, unsigned long nr_segs
)
124 #ifndef CONFIG_NFS_SWAP
125 dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
126 iocb
->ki_filp
->f_path
.dentry
->d_name
.name
,
127 (long long) pos
, nr_segs
);
131 VM_BUG_ON(iocb
->ki_left
!= PAGE_SIZE
);
132 VM_BUG_ON(iocb
->ki_nbytes
!= PAGE_SIZE
);
134 if (rw
== READ
|| rw
== KERNEL_READ
)
135 return nfs_file_direct_read(iocb
, iov
, nr_segs
, pos
,
136 rw
== READ
? true : false);
137 return nfs_file_direct_write(iocb
, iov
, nr_segs
, pos
,
138 rw
== WRITE
? true : false);
139 #endif /* CONFIG_NFS_SWAP */
142 static void nfs_direct_release_pages(struct page
**pages
, unsigned int npages
)
145 for (i
= 0; i
< npages
; i
++)
146 page_cache_release(pages
[i
]);
149 void nfs_init_cinfo_from_dreq(struct nfs_commit_info
*cinfo
,
150 struct nfs_direct_req
*dreq
)
152 cinfo
->lock
= &dreq
->lock
;
153 cinfo
->mds
= &dreq
->mds_cinfo
;
154 cinfo
->ds
= &dreq
->ds_cinfo
;
156 cinfo
->completion_ops
= &nfs_direct_commit_completion_ops
;
159 static inline struct nfs_direct_req
*nfs_direct_req_alloc(void)
161 struct nfs_direct_req
*dreq
;
163 dreq
= kmem_cache_zalloc(nfs_direct_cachep
, GFP_KERNEL
);
167 kref_init(&dreq
->kref
);
168 kref_get(&dreq
->kref
);
169 init_completion(&dreq
->completion
);
170 INIT_LIST_HEAD(&dreq
->mds_cinfo
.list
);
171 INIT_WORK(&dreq
->work
, nfs_direct_write_schedule_work
);
172 spin_lock_init(&dreq
->lock
);
177 static void nfs_direct_req_free(struct kref
*kref
)
179 struct nfs_direct_req
*dreq
= container_of(kref
, struct nfs_direct_req
, kref
);
181 if (dreq
->l_ctx
!= NULL
)
182 nfs_put_lock_context(dreq
->l_ctx
);
183 if (dreq
->ctx
!= NULL
)
184 put_nfs_open_context(dreq
->ctx
);
185 kmem_cache_free(nfs_direct_cachep
, dreq
);
188 static void nfs_direct_req_release(struct nfs_direct_req
*dreq
)
190 kref_put(&dreq
->kref
, nfs_direct_req_free
);
194 * Collects and returns the final error value/byte-count.
196 static ssize_t
nfs_direct_wait(struct nfs_direct_req
*dreq
)
198 ssize_t result
= -EIOCBQUEUED
;
200 /* Async requests don't wait here */
204 result
= wait_for_completion_killable(&dreq
->completion
);
207 result
= dreq
->error
;
209 result
= dreq
->count
;
212 return (ssize_t
) result
;
216 * Synchronous I/O uses a stack-allocated iocb. Thus we can't trust
217 * the iocb is still valid here if this is a synchronous request.
219 static void nfs_direct_complete(struct nfs_direct_req
*dreq
)
222 long res
= (long) dreq
->error
;
224 res
= (long) dreq
->count
;
225 aio_complete(dreq
->iocb
, res
, 0);
227 complete_all(&dreq
->completion
);
229 nfs_direct_req_release(dreq
);
232 static void nfs_direct_readpage_release(struct nfs_page
*req
)
234 dprintk("NFS: direct read done (%s/%lld %d@%lld)\n",
235 req
->wb_context
->dentry
->d_inode
->i_sb
->s_id
,
236 (long long)NFS_FILEID(req
->wb_context
->dentry
->d_inode
),
238 (long long)req_offset(req
));
239 nfs_release_request(req
);
242 static void nfs_direct_read_completion(struct nfs_pgio_header
*hdr
)
244 unsigned long bytes
= 0;
245 struct nfs_direct_req
*dreq
= hdr
->dreq
;
247 if (test_bit(NFS_IOHDR_REDO
, &hdr
->flags
))
250 spin_lock(&dreq
->lock
);
251 if (test_bit(NFS_IOHDR_ERROR
, &hdr
->flags
) && (hdr
->good_bytes
== 0))
252 dreq
->error
= hdr
->error
;
254 dreq
->count
+= hdr
->good_bytes
;
255 spin_unlock(&dreq
->lock
);
257 while (!list_empty(&hdr
->pages
)) {
258 struct nfs_page
*req
= nfs_list_entry(hdr
->pages
.next
);
259 struct page
*page
= req
->wb_page
;
261 if (test_bit(NFS_IOHDR_EOF
, &hdr
->flags
)) {
262 if (bytes
> hdr
->good_bytes
)
263 zero_user(page
, 0, PAGE_SIZE
);
264 else if (hdr
->good_bytes
- bytes
< PAGE_SIZE
)
265 zero_user_segment(page
,
266 hdr
->good_bytes
& ~PAGE_MASK
,
269 if (!PageCompound(page
)) {
270 if (test_bit(NFS_IOHDR_ERROR
, &hdr
->flags
)) {
271 if (bytes
< hdr
->good_bytes
)
272 set_page_dirty(page
);
274 set_page_dirty(page
);
276 bytes
+= req
->wb_bytes
;
277 nfs_list_remove_request(req
);
278 nfs_direct_readpage_release(req
);
282 nfs_direct_complete(dreq
);
286 static void nfs_read_sync_pgio_error(struct list_head
*head
)
288 struct nfs_page
*req
;
290 while (!list_empty(head
)) {
291 req
= nfs_list_entry(head
->next
);
292 nfs_list_remove_request(req
);
293 nfs_release_request(req
);
297 static void nfs_direct_pgio_init(struct nfs_pgio_header
*hdr
)
302 static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops
= {
303 .error_cleanup
= nfs_read_sync_pgio_error
,
304 .init_hdr
= nfs_direct_pgio_init
,
305 .completion
= nfs_direct_read_completion
,
309 * For each rsize'd chunk of the user's buffer, dispatch an NFS READ
310 * operation. If nfs_readdata_alloc() or get_user_pages() fails,
311 * bail and stop sending more reads. Read length accounting is
312 * handled automatically by nfs_direct_read_result(). Otherwise, if
313 * no requests have been sent, just return an error.
315 static ssize_t
nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor
*desc
,
316 const struct iovec
*iov
,
317 loff_t pos
, bool uio
)
319 struct nfs_direct_req
*dreq
= desc
->pg_dreq
;
320 struct nfs_open_context
*ctx
= dreq
->ctx
;
321 struct inode
*inode
= ctx
->dentry
->d_inode
;
322 unsigned long user_addr
= (unsigned long)iov
->iov_base
;
323 size_t count
= iov
->iov_len
;
324 size_t rsize
= NFS_SERVER(inode
)->rsize
;
328 struct page
**pagevec
= NULL
;
335 pgbase
= user_addr
& ~PAGE_MASK
;
336 bytes
= min(max_t(size_t, rsize
, PAGE_SIZE
), count
);
339 npages
= nfs_page_array_len(pgbase
, bytes
);
341 pagevec
= kmalloc(npages
* sizeof(struct page
*),
346 down_read(¤t
->mm
->mmap_sem
);
347 result
= get_user_pages(current
, current
->mm
, user_addr
,
348 npages
, 1, 0, pagevec
, NULL
);
349 up_read(¤t
->mm
->mmap_sem
);
353 WARN_ON(npages
!= 1);
354 result
= get_kernel_page(user_addr
, 1, pagevec
);
355 if (WARN_ON(result
!= 1))
359 if ((unsigned)result
< npages
) {
360 bytes
= result
* PAGE_SIZE
;
361 if (bytes
<= pgbase
) {
362 nfs_direct_release_pages(pagevec
, result
);
369 for (i
= 0; i
< npages
; i
++) {
370 struct nfs_page
*req
;
371 unsigned int req_len
= min_t(size_t, bytes
, PAGE_SIZE
- pgbase
);
372 /* XXX do we need to do the eof zeroing found in async_filler? */
373 req
= nfs_create_request(dreq
->ctx
, dreq
->inode
,
377 result
= PTR_ERR(req
);
380 req
->wb_index
= pos
>> PAGE_SHIFT
;
381 req
->wb_offset
= pos
& ~PAGE_MASK
;
382 if (!nfs_pageio_add_request(desc
, req
)) {
383 result
= desc
->pg_error
;
384 nfs_release_request(req
);
390 user_addr
+= req_len
;
394 /* The nfs_page now hold references to these pages */
395 nfs_direct_release_pages(pagevec
, npages
);
396 } while (count
!= 0 && result
>= 0);
402 return result
< 0 ? (ssize_t
) result
: -EFAULT
;
405 static ssize_t
nfs_direct_read_schedule_iovec(struct nfs_direct_req
*dreq
,
406 const struct iovec
*iov
,
407 unsigned long nr_segs
,
408 loff_t pos
, bool uio
)
410 struct nfs_pageio_descriptor desc
;
411 ssize_t result
= -EINVAL
;
412 size_t requested_bytes
= 0;
415 NFS_PROTO(dreq
->inode
)->read_pageio_init(&desc
, dreq
->inode
,
416 &nfs_direct_read_completion_ops
);
420 for (seg
= 0; seg
< nr_segs
; seg
++) {
421 const struct iovec
*vec
= &iov
[seg
];
422 result
= nfs_direct_read_schedule_segment(&desc
, vec
, pos
, uio
);
425 requested_bytes
+= result
;
426 if ((size_t)result
< vec
->iov_len
)
431 nfs_pageio_complete(&desc
);
434 * If no bytes were started, return the error, and let the
435 * generic layer handle the completion.
437 if (requested_bytes
== 0) {
438 nfs_direct_req_release(dreq
);
439 return result
< 0 ? result
: -EIO
;
443 nfs_direct_complete(dreq
);
447 static ssize_t
nfs_direct_read(struct kiocb
*iocb
, const struct iovec
*iov
,
448 unsigned long nr_segs
, loff_t pos
, bool uio
)
450 ssize_t result
= -ENOMEM
;
451 struct inode
*inode
= iocb
->ki_filp
->f_mapping
->host
;
452 struct nfs_direct_req
*dreq
;
453 struct nfs_lock_context
*l_ctx
;
455 dreq
= nfs_direct_req_alloc();
460 dreq
->ctx
= get_nfs_open_context(nfs_file_open_context(iocb
->ki_filp
));
461 l_ctx
= nfs_get_lock_context(dreq
->ctx
);
463 result
= PTR_ERR(l_ctx
);
467 if (!is_sync_kiocb(iocb
))
470 result
= nfs_direct_read_schedule_iovec(dreq
, iov
, nr_segs
, pos
, uio
);
472 result
= nfs_direct_wait(dreq
);
473 NFS_I(inode
)->read_io
+= result
;
475 nfs_direct_req_release(dreq
);
480 static void nfs_inode_dio_write_done(struct inode
*inode
)
482 nfs_zap_mapping(inode
, inode
->i_mapping
);
483 inode_dio_done(inode
);
486 #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
487 static void nfs_direct_write_reschedule(struct nfs_direct_req
*dreq
)
489 struct nfs_pageio_descriptor desc
;
490 struct nfs_page
*req
, *tmp
;
492 struct nfs_commit_info cinfo
;
495 nfs_init_cinfo_from_dreq(&cinfo
, dreq
);
496 pnfs_recover_commit_reqs(dreq
->inode
, &reqs
, &cinfo
);
497 spin_lock(cinfo
.lock
);
498 nfs_scan_commit_list(&cinfo
.mds
->list
, &reqs
, &cinfo
, 0);
499 spin_unlock(cinfo
.lock
);
504 NFS_PROTO(dreq
->inode
)->write_pageio_init(&desc
, dreq
->inode
, FLUSH_STABLE
,
505 &nfs_direct_write_completion_ops
);
508 list_for_each_entry_safe(req
, tmp
, &reqs
, wb_list
) {
509 if (!nfs_pageio_add_request(&desc
, req
)) {
510 nfs_list_remove_request(req
);
511 nfs_list_add_request(req
, &failed
);
512 spin_lock(cinfo
.lock
);
515 spin_unlock(cinfo
.lock
);
517 nfs_release_request(req
);
519 nfs_pageio_complete(&desc
);
521 while (!list_empty(&failed
)) {
522 req
= nfs_list_entry(failed
.next
);
523 nfs_list_remove_request(req
);
524 nfs_unlock_and_release_request(req
);
528 nfs_direct_write_complete(dreq
, dreq
->inode
);
531 static void nfs_direct_commit_complete(struct nfs_commit_data
*data
)
533 struct nfs_direct_req
*dreq
= data
->dreq
;
534 struct nfs_commit_info cinfo
;
535 struct nfs_page
*req
;
536 int status
= data
->task
.tk_status
;
538 nfs_init_cinfo_from_dreq(&cinfo
, dreq
);
540 dprintk("NFS: %5u commit failed with error %d.\n",
541 data
->task
.tk_pid
, status
);
542 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
543 } else if (memcmp(&dreq
->verf
, &data
->verf
, sizeof(data
->verf
))) {
544 dprintk("NFS: %5u commit verify failed\n", data
->task
.tk_pid
);
545 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
548 dprintk("NFS: %5u commit returned %d\n", data
->task
.tk_pid
, status
);
549 while (!list_empty(&data
->pages
)) {
550 req
= nfs_list_entry(data
->pages
.next
);
551 nfs_list_remove_request(req
);
552 if (dreq
->flags
== NFS_ODIRECT_RESCHED_WRITES
) {
553 /* Note the rewrite will go through mds */
554 nfs_mark_request_commit(req
, NULL
, &cinfo
);
556 nfs_release_request(req
);
557 nfs_unlock_and_release_request(req
);
560 if (atomic_dec_and_test(&cinfo
.mds
->rpcs_out
))
561 nfs_direct_write_complete(dreq
, data
->inode
);
564 static void nfs_direct_error_cleanup(struct nfs_inode
*nfsi
)
566 /* There is no lock to clear */
569 static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops
= {
570 .completion
= nfs_direct_commit_complete
,
571 .error_cleanup
= nfs_direct_error_cleanup
,
574 static void nfs_direct_commit_schedule(struct nfs_direct_req
*dreq
)
577 struct nfs_commit_info cinfo
;
580 nfs_init_cinfo_from_dreq(&cinfo
, dreq
);
581 nfs_scan_commit(dreq
->inode
, &mds_list
, &cinfo
);
582 res
= nfs_generic_commit_list(dreq
->inode
, &mds_list
, 0, &cinfo
);
583 if (res
< 0) /* res == -ENOMEM */
584 nfs_direct_write_reschedule(dreq
);
587 static void nfs_direct_write_schedule_work(struct work_struct
*work
)
589 struct nfs_direct_req
*dreq
= container_of(work
, struct nfs_direct_req
, work
);
590 int flags
= dreq
->flags
;
594 case NFS_ODIRECT_DO_COMMIT
:
595 nfs_direct_commit_schedule(dreq
);
597 case NFS_ODIRECT_RESCHED_WRITES
:
598 nfs_direct_write_reschedule(dreq
);
601 nfs_inode_dio_write_done(dreq
->inode
);
602 nfs_direct_complete(dreq
);
606 static void nfs_direct_write_complete(struct nfs_direct_req
*dreq
, struct inode
*inode
)
608 schedule_work(&dreq
->work
); /* Calls nfs_direct_write_schedule_work */
612 static void nfs_direct_write_schedule_work(struct work_struct
*work
)
616 static void nfs_direct_write_complete(struct nfs_direct_req
*dreq
, struct inode
*inode
)
618 nfs_inode_dio_write_done(inode
);
619 nfs_direct_complete(dreq
);
624 * NB: Return the value of the first error return code. Subsequent
625 * errors after the first one are ignored.
628 * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE
629 * operation. If nfs_writedata_alloc() or get_user_pages() fails,
630 * bail and stop sending more writes. Write length accounting is
631 * handled automatically by nfs_direct_write_result(). Otherwise, if
632 * no requests have been sent, just return an error.
634 static ssize_t
nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor
*desc
,
635 const struct iovec
*iov
,
636 loff_t pos
, bool uio
)
638 struct nfs_direct_req
*dreq
= desc
->pg_dreq
;
639 struct nfs_open_context
*ctx
= dreq
->ctx
;
640 struct inode
*inode
= ctx
->dentry
->d_inode
;
641 unsigned long user_addr
= (unsigned long)iov
->iov_base
;
642 size_t count
= iov
->iov_len
;
643 size_t wsize
= NFS_SERVER(inode
)->wsize
;
647 struct page
**pagevec
= NULL
;
654 pgbase
= user_addr
& ~PAGE_MASK
;
655 bytes
= min(max_t(size_t, wsize
, PAGE_SIZE
), count
);
658 npages
= nfs_page_array_len(pgbase
, bytes
);
660 pagevec
= kmalloc(npages
* sizeof(struct page
*), GFP_KERNEL
);
665 down_read(¤t
->mm
->mmap_sem
);
666 result
= get_user_pages(current
, current
->mm
, user_addr
,
667 npages
, 0, 0, pagevec
, NULL
);
668 up_read(¤t
->mm
->mmap_sem
);
672 WARN_ON(npages
!= 1);
673 result
= get_kernel_page(user_addr
, 0, pagevec
);
674 if (WARN_ON(result
!= 1))
678 if ((unsigned)result
< npages
) {
679 bytes
= result
* PAGE_SIZE
;
680 if (bytes
<= pgbase
) {
681 nfs_direct_release_pages(pagevec
, result
);
688 for (i
= 0; i
< npages
; i
++) {
689 struct nfs_page
*req
;
690 unsigned int req_len
= min_t(size_t, bytes
, PAGE_SIZE
- pgbase
);
692 req
= nfs_create_request(dreq
->ctx
, dreq
->inode
,
696 result
= PTR_ERR(req
);
699 nfs_lock_request(req
);
700 req
->wb_index
= pos
>> PAGE_SHIFT
;
701 req
->wb_offset
= pos
& ~PAGE_MASK
;
702 if (!nfs_pageio_add_request(desc
, req
)) {
703 result
= desc
->pg_error
;
704 nfs_unlock_and_release_request(req
);
710 user_addr
+= req_len
;
714 /* The nfs_page now hold references to these pages */
715 nfs_direct_release_pages(pagevec
, npages
);
716 } while (count
!= 0 && result
>= 0);
722 return result
< 0 ? (ssize_t
) result
: -EFAULT
;
725 static void nfs_direct_write_completion(struct nfs_pgio_header
*hdr
)
727 struct nfs_direct_req
*dreq
= hdr
->dreq
;
728 struct nfs_commit_info cinfo
;
730 struct nfs_page
*req
= nfs_list_entry(hdr
->pages
.next
);
732 if (test_bit(NFS_IOHDR_REDO
, &hdr
->flags
))
735 nfs_init_cinfo_from_dreq(&cinfo
, dreq
);
737 spin_lock(&dreq
->lock
);
739 if (test_bit(NFS_IOHDR_ERROR
, &hdr
->flags
)) {
741 dreq
->error
= hdr
->error
;
743 if (dreq
->error
!= 0)
744 bit
= NFS_IOHDR_ERROR
;
746 dreq
->count
+= hdr
->good_bytes
;
747 if (test_bit(NFS_IOHDR_NEED_RESCHED
, &hdr
->flags
)) {
748 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
749 bit
= NFS_IOHDR_NEED_RESCHED
;
750 } else if (test_bit(NFS_IOHDR_NEED_COMMIT
, &hdr
->flags
)) {
751 if (dreq
->flags
== NFS_ODIRECT_RESCHED_WRITES
)
752 bit
= NFS_IOHDR_NEED_RESCHED
;
753 else if (dreq
->flags
== 0) {
754 memcpy(&dreq
->verf
, hdr
->verf
,
756 bit
= NFS_IOHDR_NEED_COMMIT
;
757 dreq
->flags
= NFS_ODIRECT_DO_COMMIT
;
758 } else if (dreq
->flags
== NFS_ODIRECT_DO_COMMIT
) {
759 if (memcmp(&dreq
->verf
, hdr
->verf
, sizeof(dreq
->verf
))) {
760 dreq
->flags
= NFS_ODIRECT_RESCHED_WRITES
;
761 bit
= NFS_IOHDR_NEED_RESCHED
;
763 bit
= NFS_IOHDR_NEED_COMMIT
;
767 spin_unlock(&dreq
->lock
);
769 while (!list_empty(&hdr
->pages
)) {
770 req
= nfs_list_entry(hdr
->pages
.next
);
771 nfs_list_remove_request(req
);
773 case NFS_IOHDR_NEED_RESCHED
:
774 case NFS_IOHDR_NEED_COMMIT
:
775 kref_get(&req
->wb_kref
);
776 nfs_mark_request_commit(req
, hdr
->lseg
, &cinfo
);
778 nfs_unlock_and_release_request(req
);
783 nfs_direct_write_complete(dreq
, hdr
->inode
);
787 static void nfs_write_sync_pgio_error(struct list_head
*head
)
789 struct nfs_page
*req
;
791 while (!list_empty(head
)) {
792 req
= nfs_list_entry(head
->next
);
793 nfs_list_remove_request(req
);
794 nfs_unlock_and_release_request(req
);
798 static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops
= {
799 .error_cleanup
= nfs_write_sync_pgio_error
,
800 .init_hdr
= nfs_direct_pgio_init
,
801 .completion
= nfs_direct_write_completion
,
804 static ssize_t
nfs_direct_write_schedule_iovec(struct nfs_direct_req
*dreq
,
805 const struct iovec
*iov
,
806 unsigned long nr_segs
,
807 loff_t pos
, bool uio
)
809 struct nfs_pageio_descriptor desc
;
810 struct inode
*inode
= dreq
->inode
;
812 size_t requested_bytes
= 0;
815 NFS_PROTO(inode
)->write_pageio_init(&desc
, inode
, FLUSH_COND_STABLE
,
816 &nfs_direct_write_completion_ops
);
819 atomic_inc(&inode
->i_dio_count
);
821 for (seg
= 0; seg
< nr_segs
; seg
++) {
822 const struct iovec
*vec
= &iov
[seg
];
823 result
= nfs_direct_write_schedule_segment(&desc
, vec
, pos
, uio
);
826 requested_bytes
+= result
;
827 if ((size_t)result
< vec
->iov_len
)
831 nfs_pageio_complete(&desc
);
832 NFS_I(dreq
->inode
)->write_io
+= desc
.pg_bytes_written
;
835 * If no bytes were started, return the error, and let the
836 * generic layer handle the completion.
838 if (requested_bytes
== 0) {
839 inode_dio_done(inode
);
840 nfs_direct_req_release(dreq
);
841 return result
< 0 ? result
: -EIO
;
845 nfs_direct_write_complete(dreq
, dreq
->inode
);
849 static ssize_t
nfs_direct_write(struct kiocb
*iocb
, const struct iovec
*iov
,
850 unsigned long nr_segs
, loff_t pos
,
851 size_t count
, bool uio
)
853 ssize_t result
= -ENOMEM
;
854 struct inode
*inode
= iocb
->ki_filp
->f_mapping
->host
;
855 struct nfs_direct_req
*dreq
;
856 struct nfs_lock_context
*l_ctx
;
858 dreq
= nfs_direct_req_alloc();
863 dreq
->ctx
= get_nfs_open_context(nfs_file_open_context(iocb
->ki_filp
));
864 l_ctx
= nfs_get_lock_context(dreq
->ctx
);
866 result
= PTR_ERR(l_ctx
);
870 if (!is_sync_kiocb(iocb
))
873 result
= nfs_direct_write_schedule_iovec(dreq
, iov
, nr_segs
, pos
, uio
);
875 result
= nfs_direct_wait(dreq
);
877 nfs_direct_req_release(dreq
);
883 * nfs_file_direct_read - file direct read operation for NFS files
884 * @iocb: target I/O control block
885 * @iov: vector of user buffers into which to read data
886 * @nr_segs: size of iov vector
887 * @pos: byte offset in file where reading starts
889 * We use this function for direct reads instead of calling
890 * generic_file_aio_read() in order to avoid gfar's check to see if
891 * the request starts before the end of the file. For that check
892 * to work, we must generate a GETATTR before each direct read, and
893 * even then there is a window between the GETATTR and the subsequent
894 * READ where the file size could change. Our preference is simply
895 * to do all reads the application wants, and the server will take
896 * care of managing the end of file boundary.
898 * This function also eliminates unnecessarily updating the file's
899 * atime locally, as the NFS server sets the file's atime, and this
900 * client must read the updated atime from the server back into its
903 ssize_t
nfs_file_direct_read(struct kiocb
*iocb
, const struct iovec
*iov
,
904 unsigned long nr_segs
, loff_t pos
, bool uio
)
906 ssize_t retval
= -EINVAL
;
907 struct file
*file
= iocb
->ki_filp
;
908 struct address_space
*mapping
= file
->f_mapping
;
911 count
= iov_length(iov
, nr_segs
);
912 nfs_add_stats(mapping
->host
, NFSIOS_DIRECTREADBYTES
, count
);
914 dfprintk(FILE, "NFS: direct read(%s/%s, %zd@%Ld)\n",
915 file
->f_path
.dentry
->d_parent
->d_name
.name
,
916 file
->f_path
.dentry
->d_name
.name
,
917 count
, (long long) pos
);
923 retval
= nfs_sync_mapping(mapping
);
927 task_io_account_read(count
);
929 retval
= nfs_direct_read(iocb
, iov
, nr_segs
, pos
, uio
);
931 iocb
->ki_pos
= pos
+ retval
;
938 * nfs_file_direct_write - file direct write operation for NFS files
939 * @iocb: target I/O control block
940 * @iov: vector of user buffers from which to write data
941 * @nr_segs: size of iov vector
942 * @pos: byte offset in file where writing starts
944 * We use this function for direct writes instead of calling
945 * generic_file_aio_write() in order to avoid taking the inode
946 * semaphore and updating the i_size. The NFS server will set
947 * the new i_size and this client must read the updated size
948 * back into its cache. We let the server do generic write
949 * parameter checking and report problems.
951 * We eliminate local atime updates, see direct read above.
953 * We avoid unnecessary page cache invalidations for normal cached
954 * readers of this file.
956 * Note that O_APPEND is not supported for NFS direct writes, as there
957 * is no atomic O_APPEND write facility in the NFS protocol.
959 ssize_t
nfs_file_direct_write(struct kiocb
*iocb
, const struct iovec
*iov
,
960 unsigned long nr_segs
, loff_t pos
, bool uio
)
962 ssize_t retval
= -EINVAL
;
963 struct file
*file
= iocb
->ki_filp
;
964 struct address_space
*mapping
= file
->f_mapping
;
967 count
= iov_length(iov
, nr_segs
);
968 nfs_add_stats(mapping
->host
, NFSIOS_DIRECTWRITTENBYTES
, count
);
970 dfprintk(FILE, "NFS: direct write(%s/%s, %zd@%Ld)\n",
971 file
->f_path
.dentry
->d_parent
->d_name
.name
,
972 file
->f_path
.dentry
->d_name
.name
,
973 count
, (long long) pos
);
975 retval
= generic_write_checks(file
, &pos
, &count
, 0);
980 if ((ssize_t
) count
< 0)
986 retval
= nfs_sync_mapping(mapping
);
990 task_io_account_write(count
);
992 retval
= nfs_direct_write(iocb
, iov
, nr_segs
, pos
, count
, uio
);
994 struct inode
*inode
= mapping
->host
;
996 iocb
->ki_pos
= pos
+ retval
;
997 spin_lock(&inode
->i_lock
);
998 if (i_size_read(inode
) < iocb
->ki_pos
)
999 i_size_write(inode
, iocb
->ki_pos
);
1000 spin_unlock(&inode
->i_lock
);
1007 * nfs_init_directcache - create a slab cache for nfs_direct_req structures
1010 int __init
nfs_init_directcache(void)
1012 nfs_direct_cachep
= kmem_cache_create("nfs_direct_cache",
1013 sizeof(struct nfs_direct_req
),
1014 0, (SLAB_RECLAIM_ACCOUNT
|
1017 if (nfs_direct_cachep
== NULL
)
1024 * nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures
1027 void nfs_destroy_directcache(void)
1029 kmem_cache_destroy(nfs_direct_cachep
);