2 * linux/fs/nfs/pagelist.c
4 * A set of helper functions for managing NFS read and write requests.
5 * The main purpose of these routines is to provide support for the
6 * coalescing of several requests into a single RPC call.
8 * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
12 #include <linux/slab.h>
13 #include <linux/file.h>
14 #include <linux/sched.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/nfs.h>
17 #include <linux/nfs3.h>
18 #include <linux/nfs4.h>
19 #include <linux/nfs_page.h>
20 #include <linux/nfs_fs.h>
21 #include <linux/nfs_mount.h>
22 #include <linux/export.h>
27 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
29 static struct kmem_cache
*nfs_page_cachep
;
30 static const struct rpc_call_ops nfs_pgio_common_ops
;
32 static void nfs_free_request(struct nfs_page
*);
34 static bool nfs_pgarray_set(struct nfs_page_array
*p
, unsigned int pagecount
)
36 p
->npages
= pagecount
;
37 if (pagecount
<= ARRAY_SIZE(p
->page_array
))
38 p
->pagevec
= p
->page_array
;
40 p
->pagevec
= kcalloc(pagecount
, sizeof(struct page
*), GFP_KERNEL
);
44 return p
->pagevec
!= NULL
;
47 void nfs_pgheader_init(struct nfs_pageio_descriptor
*desc
,
48 struct nfs_pgio_header
*hdr
,
49 void (*release
)(struct nfs_pgio_header
*hdr
))
51 hdr
->req
= nfs_list_entry(desc
->pg_list
.next
);
52 hdr
->inode
= desc
->pg_inode
;
53 hdr
->cred
= hdr
->req
->wb_context
->cred
;
54 hdr
->io_start
= req_offset(hdr
->req
);
55 hdr
->good_bytes
= desc
->pg_count
;
56 hdr
->dreq
= desc
->pg_dreq
;
57 hdr
->layout_private
= desc
->pg_layout_private
;
58 hdr
->release
= release
;
59 hdr
->completion_ops
= desc
->pg_completion_ops
;
60 if (hdr
->completion_ops
->init_hdr
)
61 hdr
->completion_ops
->init_hdr(hdr
);
63 EXPORT_SYMBOL_GPL(nfs_pgheader_init
);
65 void nfs_set_pgio_error(struct nfs_pgio_header
*hdr
, int error
, loff_t pos
)
67 spin_lock(&hdr
->lock
);
68 if (pos
< hdr
->io_start
+ hdr
->good_bytes
) {
69 set_bit(NFS_IOHDR_ERROR
, &hdr
->flags
);
70 clear_bit(NFS_IOHDR_EOF
, &hdr
->flags
);
71 hdr
->good_bytes
= pos
- hdr
->io_start
;
74 spin_unlock(&hdr
->lock
);
77 static inline struct nfs_page
*
80 struct nfs_page
*p
= kmem_cache_zalloc(nfs_page_cachep
, GFP_NOIO
);
82 INIT_LIST_HEAD(&p
->wb_list
);
87 nfs_page_free(struct nfs_page
*p
)
89 kmem_cache_free(nfs_page_cachep
, p
);
93 nfs_iocounter_inc(struct nfs_io_counter
*c
)
95 atomic_inc(&c
->io_count
);
99 nfs_iocounter_dec(struct nfs_io_counter
*c
)
101 if (atomic_dec_and_test(&c
->io_count
)) {
102 clear_bit(NFS_IO_INPROGRESS
, &c
->flags
);
103 smp_mb__after_atomic();
104 wake_up_bit(&c
->flags
, NFS_IO_INPROGRESS
);
109 __nfs_iocounter_wait(struct nfs_io_counter
*c
)
111 wait_queue_head_t
*wq
= bit_waitqueue(&c
->flags
, NFS_IO_INPROGRESS
);
112 DEFINE_WAIT_BIT(q
, &c
->flags
, NFS_IO_INPROGRESS
);
116 prepare_to_wait(wq
, &q
.wait
, TASK_KILLABLE
);
117 set_bit(NFS_IO_INPROGRESS
, &c
->flags
);
118 if (atomic_read(&c
->io_count
) == 0)
120 ret
= nfs_wait_bit_killable(&c
->flags
);
121 } while (atomic_read(&c
->io_count
) != 0);
122 finish_wait(wq
, &q
.wait
);
127 * nfs_iocounter_wait - wait for i/o to complete
128 * @c: nfs_io_counter to use
130 * returns -ERESTARTSYS if interrupted by a fatal signal.
131 * Otherwise returns 0 once the io_count hits 0.
134 nfs_iocounter_wait(struct nfs_io_counter
*c
)
136 if (atomic_read(&c
->io_count
) == 0)
138 return __nfs_iocounter_wait(c
);
141 static int nfs_wait_bit_uninterruptible(void *word
)
148 * nfs_page_group_lock - lock the head of the page group
149 * @req - request in group that is to be locked
151 * this lock must be held if modifying the page group list
154 nfs_page_group_lock(struct nfs_page
*req
)
156 struct nfs_page
*head
= req
->wb_head
;
158 WARN_ON_ONCE(head
!= head
->wb_head
);
160 wait_on_bit_lock(&head
->wb_flags
, PG_HEADLOCK
,
161 nfs_wait_bit_uninterruptible
,
162 TASK_UNINTERRUPTIBLE
);
166 * nfs_page_group_unlock - unlock the head of the page group
167 * @req - request in group that is to be unlocked
170 nfs_page_group_unlock(struct nfs_page
*req
)
172 struct nfs_page
*head
= req
->wb_head
;
174 WARN_ON_ONCE(head
!= head
->wb_head
);
176 smp_mb__before_atomic();
177 clear_bit(PG_HEADLOCK
, &head
->wb_flags
);
178 smp_mb__after_atomic();
179 wake_up_bit(&head
->wb_flags
, PG_HEADLOCK
);
183 * nfs_page_group_sync_on_bit_locked
185 * must be called with page group lock held
188 nfs_page_group_sync_on_bit_locked(struct nfs_page
*req
, unsigned int bit
)
190 struct nfs_page
*head
= req
->wb_head
;
191 struct nfs_page
*tmp
;
193 WARN_ON_ONCE(!test_bit(PG_HEADLOCK
, &head
->wb_flags
));
194 WARN_ON_ONCE(test_and_set_bit(bit
, &req
->wb_flags
));
196 tmp
= req
->wb_this_page
;
198 if (!test_bit(bit
, &tmp
->wb_flags
))
200 tmp
= tmp
->wb_this_page
;
203 /* true! reset all bits */
206 clear_bit(bit
, &tmp
->wb_flags
);
207 tmp
= tmp
->wb_this_page
;
208 } while (tmp
!= req
);
214 * nfs_page_group_sync_on_bit - set bit on current request, but only
215 * return true if the bit is set for all requests in page group
216 * @req - request in page group
217 * @bit - PG_* bit that is used to sync page group
219 bool nfs_page_group_sync_on_bit(struct nfs_page
*req
, unsigned int bit
)
223 nfs_page_group_lock(req
);
224 ret
= nfs_page_group_sync_on_bit_locked(req
, bit
);
225 nfs_page_group_unlock(req
);
231 * nfs_page_group_init - Initialize the page group linkage for @req
232 * @req - a new nfs request
233 * @prev - the previous request in page group, or NULL if @req is the first
234 * or only request in the group (the head).
237 nfs_page_group_init(struct nfs_page
*req
, struct nfs_page
*prev
)
239 WARN_ON_ONCE(prev
== req
);
243 req
->wb_this_page
= req
;
245 WARN_ON_ONCE(prev
->wb_this_page
!= prev
->wb_head
);
246 WARN_ON_ONCE(!test_bit(PG_HEADLOCK
, &prev
->wb_head
->wb_flags
));
247 req
->wb_head
= prev
->wb_head
;
248 req
->wb_this_page
= prev
->wb_this_page
;
249 prev
->wb_this_page
= req
;
251 /* grab extra ref if head request has extra ref from
252 * the write/commit path to handle handoff between write
253 * and commit lists */
254 if (test_bit(PG_INODE_REF
, &prev
->wb_head
->wb_flags
))
255 kref_get(&req
->wb_kref
);
260 * nfs_page_group_destroy - sync the destruction of page groups
261 * @req - request that no longer needs the page group
263 * releases the page group reference from each member once all
264 * members have called this function.
267 nfs_page_group_destroy(struct kref
*kref
)
269 struct nfs_page
*req
= container_of(kref
, struct nfs_page
, wb_kref
);
270 struct nfs_page
*tmp
, *next
;
272 if (!nfs_page_group_sync_on_bit(req
, PG_TEARDOWN
))
277 next
= tmp
->wb_this_page
;
278 /* unlink and free */
279 tmp
->wb_this_page
= tmp
;
281 nfs_free_request(tmp
);
283 } while (tmp
!= req
);
287 * nfs_create_request - Create an NFS read/write request.
288 * @ctx: open context to use
289 * @page: page to write
290 * @last: last nfs request created for this page group or NULL if head
291 * @offset: starting offset within the page for the write
292 * @count: number of bytes to read/write
294 * The page must be locked by the caller. This makes sure we never
295 * create two different requests for the same page.
296 * User should ensure it is safe to sleep in this function.
299 nfs_create_request(struct nfs_open_context
*ctx
, struct page
*page
,
300 struct nfs_page
*last
, unsigned int offset
,
303 struct nfs_page
*req
;
304 struct nfs_lock_context
*l_ctx
;
306 if (test_bit(NFS_CONTEXT_BAD
, &ctx
->flags
))
307 return ERR_PTR(-EBADF
);
308 /* try to allocate the request struct */
309 req
= nfs_page_alloc();
311 return ERR_PTR(-ENOMEM
);
313 /* get lock context early so we can deal with alloc failures */
314 l_ctx
= nfs_get_lock_context(ctx
);
317 return ERR_CAST(l_ctx
);
319 req
->wb_lock_context
= l_ctx
;
320 nfs_iocounter_inc(&l_ctx
->io_count
);
322 /* Initialize the request struct. Initially, we assume a
323 * long write-back delay. This will be adjusted in
324 * update_nfs_request below if the region is not locked. */
326 req
->wb_index
= page_file_index(page
);
327 page_cache_get(page
);
328 req
->wb_offset
= offset
;
329 req
->wb_pgbase
= offset
;
330 req
->wb_bytes
= count
;
331 req
->wb_context
= get_nfs_open_context(ctx
);
332 kref_init(&req
->wb_kref
);
333 nfs_page_group_init(req
, last
);
338 * nfs_unlock_request - Unlock request and wake up sleepers.
341 void nfs_unlock_request(struct nfs_page
*req
)
343 if (!NFS_WBACK_BUSY(req
)) {
344 printk(KERN_ERR
"NFS: Invalid unlock attempted\n");
347 smp_mb__before_atomic();
348 clear_bit(PG_BUSY
, &req
->wb_flags
);
349 smp_mb__after_atomic();
350 wake_up_bit(&req
->wb_flags
, PG_BUSY
);
354 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
357 void nfs_unlock_and_release_request(struct nfs_page
*req
)
359 nfs_unlock_request(req
);
360 nfs_release_request(req
);
364 * nfs_clear_request - Free up all resources allocated to the request
367 * Release page and open context resources associated with a read/write
368 * request after it has completed.
370 static void nfs_clear_request(struct nfs_page
*req
)
372 struct page
*page
= req
->wb_page
;
373 struct nfs_open_context
*ctx
= req
->wb_context
;
374 struct nfs_lock_context
*l_ctx
= req
->wb_lock_context
;
377 page_cache_release(page
);
381 nfs_iocounter_dec(&l_ctx
->io_count
);
382 nfs_put_lock_context(l_ctx
);
383 req
->wb_lock_context
= NULL
;
386 put_nfs_open_context(ctx
);
387 req
->wb_context
= NULL
;
392 * nfs_release_request - Release the count on an NFS read/write request
393 * @req: request to release
395 * Note: Should never be called with the spinlock held!
397 static void nfs_free_request(struct nfs_page
*req
)
399 WARN_ON_ONCE(req
->wb_this_page
!= req
);
401 /* extra debug: make sure no sync bits are still set */
402 WARN_ON_ONCE(test_bit(PG_TEARDOWN
, &req
->wb_flags
));
403 WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE
, &req
->wb_flags
));
404 WARN_ON_ONCE(test_bit(PG_UPTODATE
, &req
->wb_flags
));
405 WARN_ON_ONCE(test_bit(PG_WB_END
, &req
->wb_flags
));
406 WARN_ON_ONCE(test_bit(PG_REMOVE
, &req
->wb_flags
));
408 /* Release struct file and open context */
409 nfs_clear_request(req
);
413 void nfs_release_request(struct nfs_page
*req
)
415 kref_put(&req
->wb_kref
, nfs_page_group_destroy
);
419 * nfs_wait_on_request - Wait for a request to complete.
420 * @req: request to wait upon.
422 * Interruptible by fatal signals only.
423 * The user is responsible for holding a count on the request.
426 nfs_wait_on_request(struct nfs_page
*req
)
428 return wait_on_bit(&req
->wb_flags
, PG_BUSY
,
429 nfs_wait_bit_uninterruptible
,
430 TASK_UNINTERRUPTIBLE
);
434 * nfs_generic_pg_test - determine if requests can be coalesced
435 * @desc: pointer to descriptor
436 * @prev: previous request in desc, or NULL
439 * Returns zero if @req can be coalesced into @desc, otherwise it returns
440 * the size of the request.
442 size_t nfs_generic_pg_test(struct nfs_pageio_descriptor
*desc
,
443 struct nfs_page
*prev
, struct nfs_page
*req
)
445 if (desc
->pg_count
> desc
->pg_bsize
) {
446 /* should never happen */
451 return min(desc
->pg_bsize
- desc
->pg_count
, (size_t)req
->wb_bytes
);
453 EXPORT_SYMBOL_GPL(nfs_generic_pg_test
);
455 static inline struct nfs_rw_header
*NFS_RW_HEADER(struct nfs_pgio_header
*hdr
)
457 return container_of(hdr
, struct nfs_rw_header
, header
);
461 * nfs_rw_header_alloc - Allocate a header for a read or write
462 * @ops: Read or write function vector
464 struct nfs_rw_header
*nfs_rw_header_alloc(const struct nfs_rw_ops
*ops
)
466 struct nfs_rw_header
*header
= ops
->rw_alloc_header();
469 struct nfs_pgio_header
*hdr
= &header
->header
;
471 INIT_LIST_HEAD(&hdr
->pages
);
472 spin_lock_init(&hdr
->lock
);
473 atomic_set(&hdr
->refcnt
, 0);
478 EXPORT_SYMBOL_GPL(nfs_rw_header_alloc
);
481 * nfs_rw_header_free - Free a read or write header
482 * @hdr: The header to free
484 void nfs_rw_header_free(struct nfs_pgio_header
*hdr
)
486 hdr
->rw_ops
->rw_free_header(NFS_RW_HEADER(hdr
));
488 EXPORT_SYMBOL_GPL(nfs_rw_header_free
);
491 * nfs_pgio_data_alloc - Allocate pageio data
492 * @hdr: The header making a request
493 * @pagecount: Number of pages to create
495 static struct nfs_pgio_data
*nfs_pgio_data_alloc(struct nfs_pgio_header
*hdr
,
496 unsigned int pagecount
)
498 struct nfs_pgio_data
*data
, *prealloc
;
500 prealloc
= &NFS_RW_HEADER(hdr
)->rpc_data
;
501 if (prealloc
->header
== NULL
)
504 data
= kzalloc(sizeof(*data
), GFP_KERNEL
);
508 if (nfs_pgarray_set(&data
->pages
, pagecount
)) {
510 atomic_inc(&hdr
->refcnt
);
512 if (data
!= prealloc
)
521 * nfs_pgio_data_release - Properly free pageio data
522 * @data: The data to release
524 void nfs_pgio_data_release(struct nfs_pgio_data
*data
)
526 struct nfs_pgio_header
*hdr
= data
->header
;
527 struct nfs_rw_header
*pageio_header
= NFS_RW_HEADER(hdr
);
529 put_nfs_open_context(data
->args
.context
);
530 if (data
->pages
.pagevec
!= data
->pages
.page_array
)
531 kfree(data
->pages
.pagevec
);
532 if (data
== &pageio_header
->rpc_data
) {
536 if (atomic_dec_and_test(&hdr
->refcnt
))
537 hdr
->completion_ops
->completion(hdr
);
538 /* Note: we only free the rpc_task after callbacks are done.
539 * See the comment in rpc_free_task() for why
543 EXPORT_SYMBOL_GPL(nfs_pgio_data_release
);
546 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
547 * @data: The pageio data
548 * @count: Number of bytes to read
549 * @offset: Initial offset
550 * @how: How to commit data (writes only)
551 * @cinfo: Commit information for the call (writes only)
553 static void nfs_pgio_rpcsetup(struct nfs_pgio_data
*data
,
554 unsigned int count
, unsigned int offset
,
555 int how
, struct nfs_commit_info
*cinfo
)
557 struct nfs_page
*req
= data
->header
->req
;
559 /* Set up the RPC argument and reply structs
560 * NB: take care not to mess about with data->commit et al. */
562 data
->args
.fh
= NFS_FH(data
->header
->inode
);
563 data
->args
.offset
= req_offset(req
) + offset
;
564 /* pnfs_set_layoutcommit needs this */
565 data
->mds_offset
= data
->args
.offset
;
566 data
->args
.pgbase
= req
->wb_pgbase
+ offset
;
567 data
->args
.pages
= data
->pages
.pagevec
;
568 data
->args
.count
= count
;
569 data
->args
.context
= get_nfs_open_context(req
->wb_context
);
570 data
->args
.lock_context
= req
->wb_lock_context
;
571 data
->args
.stable
= NFS_UNSTABLE
;
572 switch (how
& (FLUSH_STABLE
| FLUSH_COND_STABLE
)) {
575 case FLUSH_COND_STABLE
:
576 if (nfs_reqs_to_commit(cinfo
))
579 data
->args
.stable
= NFS_FILE_SYNC
;
582 data
->res
.fattr
= &data
->fattr
;
583 data
->res
.count
= count
;
585 data
->res
.verf
= &data
->verf
;
586 nfs_fattr_init(&data
->fattr
);
590 * nfs_pgio_prepare - Prepare pageio data to go over the wire
591 * @task: The current task
592 * @calldata: pageio data to prepare
594 static void nfs_pgio_prepare(struct rpc_task
*task
, void *calldata
)
596 struct nfs_pgio_data
*data
= calldata
;
598 err
= NFS_PROTO(data
->header
->inode
)->pgio_rpc_prepare(task
, data
);
603 int nfs_initiate_pgio(struct rpc_clnt
*clnt
, struct nfs_pgio_data
*data
,
604 const struct rpc_call_ops
*call_ops
, int how
, int flags
)
606 struct rpc_task
*task
;
607 struct rpc_message msg
= {
608 .rpc_argp
= &data
->args
,
609 .rpc_resp
= &data
->res
,
610 .rpc_cred
= data
->header
->cred
,
612 struct rpc_task_setup task_setup_data
= {
616 .callback_ops
= call_ops
,
617 .callback_data
= data
,
618 .workqueue
= nfsiod_workqueue
,
619 .flags
= RPC_TASK_ASYNC
| flags
,
623 data
->header
->rw_ops
->rw_initiate(data
, &msg
, &task_setup_data
, how
);
625 dprintk("NFS: %5u initiated pgio call "
626 "(req %s/%llu, %u bytes @ offset %llu)\n",
628 data
->header
->inode
->i_sb
->s_id
,
629 (unsigned long long)NFS_FILEID(data
->header
->inode
),
631 (unsigned long long)data
->args
.offset
);
633 task
= rpc_run_task(&task_setup_data
);
638 if (how
& FLUSH_SYNC
) {
639 ret
= rpc_wait_for_completion_task(task
);
641 ret
= task
->tk_status
;
647 EXPORT_SYMBOL_GPL(nfs_initiate_pgio
);
650 * nfs_pgio_error - Clean up from a pageio error
651 * @desc: IO descriptor
652 * @hdr: pageio header
654 static int nfs_pgio_error(struct nfs_pageio_descriptor
*desc
,
655 struct nfs_pgio_header
*hdr
)
657 set_bit(NFS_IOHDR_REDO
, &hdr
->flags
);
658 nfs_pgio_data_release(hdr
->data
);
660 desc
->pg_completion_ops
->error_cleanup(&desc
->pg_list
);
665 * nfs_pgio_release - Release pageio data
666 * @calldata: The pageio data to release
668 static void nfs_pgio_release(void *calldata
)
670 struct nfs_pgio_data
*data
= calldata
;
671 if (data
->header
->rw_ops
->rw_release
)
672 data
->header
->rw_ops
->rw_release(data
);
673 nfs_pgio_data_release(data
);
677 * nfs_pageio_init - initialise a page io descriptor
678 * @desc: pointer to descriptor
679 * @inode: pointer to inode
680 * @doio: pointer to io function
681 * @bsize: io block size
682 * @io_flags: extra parameters for the io function
684 void nfs_pageio_init(struct nfs_pageio_descriptor
*desc
,
686 const struct nfs_pageio_ops
*pg_ops
,
687 const struct nfs_pgio_completion_ops
*compl_ops
,
688 const struct nfs_rw_ops
*rw_ops
,
692 INIT_LIST_HEAD(&desc
->pg_list
);
693 desc
->pg_bytes_written
= 0;
695 desc
->pg_bsize
= bsize
;
698 desc
->pg_recoalesce
= 0;
699 desc
->pg_inode
= inode
;
700 desc
->pg_ops
= pg_ops
;
701 desc
->pg_completion_ops
= compl_ops
;
702 desc
->pg_rw_ops
= rw_ops
;
703 desc
->pg_ioflags
= io_flags
;
705 desc
->pg_lseg
= NULL
;
706 desc
->pg_dreq
= NULL
;
707 desc
->pg_layout_private
= NULL
;
709 EXPORT_SYMBOL_GPL(nfs_pageio_init
);
712 * nfs_pgio_result - Basic pageio error handling
713 * @task: The task that ran
714 * @calldata: Pageio data to check
716 static void nfs_pgio_result(struct rpc_task
*task
, void *calldata
)
718 struct nfs_pgio_data
*data
= calldata
;
719 struct inode
*inode
= data
->header
->inode
;
721 dprintk("NFS: %s: %5u, (status %d)\n", __func__
,
722 task
->tk_pid
, task
->tk_status
);
724 if (data
->header
->rw_ops
->rw_done(task
, data
, inode
) != 0)
726 if (task
->tk_status
< 0)
727 nfs_set_pgio_error(data
->header
, task
->tk_status
, data
->args
.offset
);
729 data
->header
->rw_ops
->rw_result(task
, data
);
733 * Create an RPC task for the given read or write request and kick it.
734 * The page must have been locked by the caller.
736 * It may happen that the page we're passed is not marked dirty.
737 * This is the case if nfs_updatepage detects a conflicting request
738 * that has been written but not committed.
740 int nfs_generic_pgio(struct nfs_pageio_descriptor
*desc
,
741 struct nfs_pgio_header
*hdr
)
743 struct nfs_page
*req
;
745 struct nfs_pgio_data
*data
;
746 struct list_head
*head
= &desc
->pg_list
;
747 struct nfs_commit_info cinfo
;
749 data
= nfs_pgio_data_alloc(hdr
, nfs_page_array_len(desc
->pg_base
,
752 return nfs_pgio_error(desc
, hdr
);
754 nfs_init_cinfo(&cinfo
, desc
->pg_inode
, desc
->pg_dreq
);
755 pages
= data
->pages
.pagevec
;
756 while (!list_empty(head
)) {
757 req
= nfs_list_entry(head
->next
);
758 nfs_list_remove_request(req
);
759 nfs_list_add_request(req
, &hdr
->pages
);
760 *pages
++ = req
->wb_page
;
763 if ((desc
->pg_ioflags
& FLUSH_COND_STABLE
) &&
764 (desc
->pg_moreio
|| nfs_reqs_to_commit(&cinfo
)))
765 desc
->pg_ioflags
&= ~FLUSH_COND_STABLE
;
767 /* Set up the argument struct */
768 nfs_pgio_rpcsetup(data
, desc
->pg_count
, 0, desc
->pg_ioflags
, &cinfo
);
770 desc
->pg_rpc_callops
= &nfs_pgio_common_ops
;
773 EXPORT_SYMBOL_GPL(nfs_generic_pgio
);
775 static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor
*desc
)
777 struct nfs_rw_header
*rw_hdr
;
778 struct nfs_pgio_header
*hdr
;
781 rw_hdr
= nfs_rw_header_alloc(desc
->pg_rw_ops
);
783 desc
->pg_completion_ops
->error_cleanup(&desc
->pg_list
);
786 hdr
= &rw_hdr
->header
;
787 nfs_pgheader_init(desc
, hdr
, nfs_rw_header_free
);
788 atomic_inc(&hdr
->refcnt
);
789 ret
= nfs_generic_pgio(desc
, hdr
);
791 ret
= nfs_initiate_pgio(NFS_CLIENT(hdr
->inode
),
792 hdr
->data
, desc
->pg_rpc_callops
,
793 desc
->pg_ioflags
, 0);
794 if (atomic_dec_and_test(&hdr
->refcnt
))
795 hdr
->completion_ops
->completion(hdr
);
799 static bool nfs_match_open_context(const struct nfs_open_context
*ctx1
,
800 const struct nfs_open_context
*ctx2
)
802 return ctx1
->cred
== ctx2
->cred
&& ctx1
->state
== ctx2
->state
;
805 static bool nfs_match_lock_context(const struct nfs_lock_context
*l1
,
806 const struct nfs_lock_context
*l2
)
808 return l1
->lockowner
.l_owner
== l2
->lockowner
.l_owner
809 && l1
->lockowner
.l_pid
== l2
->lockowner
.l_pid
;
813 * nfs_can_coalesce_requests - test two requests for compatibility
814 * @prev: pointer to nfs_page
815 * @req: pointer to nfs_page
817 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
818 * page data area they describe is contiguous, and that their RPC
819 * credentials, NFSv4 open state, and lockowners are the same.
821 * Return 'true' if this is the case, else return 'false'.
823 static bool nfs_can_coalesce_requests(struct nfs_page
*prev
,
824 struct nfs_page
*req
,
825 struct nfs_pageio_descriptor
*pgio
)
830 if (!nfs_match_open_context(req
->wb_context
, prev
->wb_context
))
832 if (req
->wb_context
->dentry
->d_inode
->i_flock
!= NULL
&&
833 !nfs_match_lock_context(req
->wb_lock_context
,
834 prev
->wb_lock_context
))
836 if (req_offset(req
) != req_offset(prev
) + prev
->wb_bytes
)
839 size
= pgio
->pg_ops
->pg_test(pgio
, prev
, req
);
840 WARN_ON_ONCE(size
> req
->wb_bytes
);
841 if (size
&& size
< req
->wb_bytes
)
842 req
->wb_bytes
= size
;
847 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
848 * @desc: destination io descriptor
851 * Returns true if the request 'req' was successfully coalesced into the
852 * existing list of pages 'desc'.
854 static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor
*desc
,
855 struct nfs_page
*req
)
857 struct nfs_page
*prev
= NULL
;
858 if (desc
->pg_count
!= 0) {
859 prev
= nfs_list_entry(desc
->pg_list
.prev
);
861 if (desc
->pg_ops
->pg_init
)
862 desc
->pg_ops
->pg_init(desc
, req
);
863 desc
->pg_base
= req
->wb_pgbase
;
865 if (!nfs_can_coalesce_requests(prev
, req
, desc
))
867 nfs_list_remove_request(req
);
868 nfs_list_add_request(req
, &desc
->pg_list
);
869 desc
->pg_count
+= req
->wb_bytes
;
874 * Helper for nfs_pageio_add_request and nfs_pageio_complete
876 static void nfs_pageio_doio(struct nfs_pageio_descriptor
*desc
)
878 if (!list_empty(&desc
->pg_list
)) {
879 int error
= desc
->pg_ops
->pg_doio(desc
);
881 desc
->pg_error
= error
;
883 desc
->pg_bytes_written
+= desc
->pg_count
;
885 if (list_empty(&desc
->pg_list
)) {
892 * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
893 * @desc: destination io descriptor
896 * This may split a request into subrequests which are all part of the
899 * Returns true if the request 'req' was successfully coalesced into the
900 * existing list of pages 'desc'.
902 static int __nfs_pageio_add_request(struct nfs_pageio_descriptor
*desc
,
903 struct nfs_page
*req
)
905 struct nfs_page
*subreq
;
906 unsigned int bytes_left
= 0;
907 unsigned int offset
, pgbase
;
909 nfs_page_group_lock(req
);
912 bytes_left
= subreq
->wb_bytes
;
913 offset
= subreq
->wb_offset
;
914 pgbase
= subreq
->wb_pgbase
;
917 if (!nfs_pageio_do_add_request(desc
, subreq
)) {
918 /* make sure pg_test call(s) did nothing */
919 WARN_ON_ONCE(subreq
->wb_bytes
!= bytes_left
);
920 WARN_ON_ONCE(subreq
->wb_offset
!= offset
);
921 WARN_ON_ONCE(subreq
->wb_pgbase
!= pgbase
);
923 nfs_page_group_unlock(req
);
925 nfs_pageio_doio(desc
);
926 if (desc
->pg_error
< 0)
929 if (desc
->pg_recoalesce
)
931 /* retry add_request for this subreq */
932 nfs_page_group_lock(req
);
936 /* check for buggy pg_test call(s) */
937 WARN_ON_ONCE(subreq
->wb_bytes
+ subreq
->wb_pgbase
> PAGE_SIZE
);
938 WARN_ON_ONCE(subreq
->wb_bytes
> bytes_left
);
939 WARN_ON_ONCE(subreq
->wb_bytes
== 0);
941 bytes_left
-= subreq
->wb_bytes
;
942 offset
+= subreq
->wb_bytes
;
943 pgbase
+= subreq
->wb_bytes
;
946 subreq
= nfs_create_request(req
->wb_context
,
948 subreq
, pgbase
, bytes_left
);
951 nfs_lock_request(subreq
);
952 subreq
->wb_offset
= offset
;
953 subreq
->wb_index
= req
->wb_index
;
955 } while (bytes_left
> 0);
957 nfs_page_group_unlock(req
);
960 desc
->pg_error
= PTR_ERR(subreq
);
961 nfs_page_group_unlock(req
);
965 static int nfs_do_recoalesce(struct nfs_pageio_descriptor
*desc
)
970 list_splice_init(&desc
->pg_list
, &head
);
971 desc
->pg_bytes_written
-= desc
->pg_count
;
974 desc
->pg_recoalesce
= 0;
976 while (!list_empty(&head
)) {
977 struct nfs_page
*req
;
979 req
= list_first_entry(&head
, struct nfs_page
, wb_list
);
980 nfs_list_remove_request(req
);
981 if (__nfs_pageio_add_request(desc
, req
))
983 if (desc
->pg_error
< 0)
987 } while (desc
->pg_recoalesce
);
991 int nfs_pageio_add_request(struct nfs_pageio_descriptor
*desc
,
992 struct nfs_page
*req
)
997 ret
= __nfs_pageio_add_request(desc
, req
);
1000 if (desc
->pg_error
< 0)
1002 ret
= nfs_do_recoalesce(desc
);
1006 EXPORT_SYMBOL_GPL(nfs_pageio_add_request
);
1009 * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor
1010 * @desc: pointer to io descriptor
1012 void nfs_pageio_complete(struct nfs_pageio_descriptor
*desc
)
1015 nfs_pageio_doio(desc
);
1016 if (!desc
->pg_recoalesce
)
1018 if (!nfs_do_recoalesce(desc
))
1022 EXPORT_SYMBOL_GPL(nfs_pageio_complete
);
1025 * nfs_pageio_cond_complete - Conditional I/O completion
1026 * @desc: pointer to io descriptor
1027 * @index: page index
1029 * It is important to ensure that processes don't try to take locks
1030 * on non-contiguous ranges of pages as that might deadlock. This
1031 * function should be called before attempting to wait on a locked
1032 * nfs_page. It will complete the I/O if the page index 'index'
1033 * is not contiguous with the existing list of pages in 'desc'.
1035 void nfs_pageio_cond_complete(struct nfs_pageio_descriptor
*desc
, pgoff_t index
)
1037 if (!list_empty(&desc
->pg_list
)) {
1038 struct nfs_page
*prev
= nfs_list_entry(desc
->pg_list
.prev
);
1039 if (index
!= prev
->wb_index
+ 1)
1040 nfs_pageio_complete(desc
);
1044 int __init
nfs_init_nfspagecache(void)
1046 nfs_page_cachep
= kmem_cache_create("nfs_page",
1047 sizeof(struct nfs_page
),
1048 0, SLAB_HWCACHE_ALIGN
,
1050 if (nfs_page_cachep
== NULL
)
1056 void nfs_destroy_nfspagecache(void)
1058 kmem_cache_destroy(nfs_page_cachep
);
1061 static const struct rpc_call_ops nfs_pgio_common_ops
= {
1062 .rpc_call_prepare
= nfs_pgio_prepare
,
1063 .rpc_call_done
= nfs_pgio_result
,
1064 .rpc_release
= nfs_pgio_release
,
1067 const struct nfs_pageio_ops nfs_pgio_rw_ops
= {
1068 .pg_test
= nfs_generic_pg_test
,
1069 .pg_doio
= nfs_generic_pg_pgios
,