6 * Partial copy of Linus' read cache modifications to fs/nfs/file.c
7 * modified for async RPC by okir@monad.swb.de
10 #include <linux/time.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/fcntl.h>
14 #include <linux/stat.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/sunrpc/clnt.h>
19 #include <linux/nfs_fs.h>
20 #include <linux/nfs_page.h>
21 #include <linux/module.h>
29 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
31 static const struct nfs_pageio_ops nfs_pageio_read_ops
;
32 static const struct rpc_call_ops nfs_read_common_ops
;
33 static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops
;
35 static struct kmem_cache
*nfs_rdata_cachep
;
37 struct nfs_read_header
*nfs_readhdr_alloc(void)
39 struct nfs_read_header
*rhdr
;
41 rhdr
= kmem_cache_zalloc(nfs_rdata_cachep
, GFP_KERNEL
);
43 struct nfs_pgio_header
*hdr
= &rhdr
->header
;
45 INIT_LIST_HEAD(&hdr
->pages
);
46 INIT_LIST_HEAD(&hdr
->rpc_list
);
47 spin_lock_init(&hdr
->lock
);
48 atomic_set(&hdr
->refcnt
, 0);
52 EXPORT_SYMBOL_GPL(nfs_readhdr_alloc
);
54 static struct nfs_read_data
*nfs_readdata_alloc(struct nfs_pgio_header
*hdr
,
55 unsigned int pagecount
)
57 struct nfs_read_data
*data
, *prealloc
;
59 prealloc
= &container_of(hdr
, struct nfs_read_header
, header
)->rpc_data
;
60 if (prealloc
->header
== NULL
)
63 data
= kzalloc(sizeof(*data
), GFP_KERNEL
);
67 if (nfs_pgarray_set(&data
->pages
, pagecount
)) {
69 atomic_inc(&hdr
->refcnt
);
79 void nfs_readhdr_free(struct nfs_pgio_header
*hdr
)
81 struct nfs_read_header
*rhdr
= container_of(hdr
, struct nfs_read_header
, header
);
83 kmem_cache_free(nfs_rdata_cachep
, rhdr
);
85 EXPORT_SYMBOL_GPL(nfs_readhdr_free
);
87 void nfs_readdata_release(struct nfs_read_data
*rdata
)
89 struct nfs_pgio_header
*hdr
= rdata
->header
;
90 struct nfs_read_header
*read_header
= container_of(hdr
, struct nfs_read_header
, header
);
92 put_nfs_open_context(rdata
->args
.context
);
93 if (rdata
->pages
.pagevec
!= rdata
->pages
.page_array
)
94 kfree(rdata
->pages
.pagevec
);
95 if (rdata
== &read_header
->rpc_data
) {
99 if (atomic_dec_and_test(&hdr
->refcnt
))
100 hdr
->completion_ops
->completion(hdr
);
101 /* Note: we only free the rpc_task after callbacks are done.
102 * See the comment in rpc_free_task() for why
106 EXPORT_SYMBOL_GPL(nfs_readdata_release
);
109 int nfs_return_empty_page(struct page
*page
)
111 zero_user(page
, 0, PAGE_CACHE_SIZE
);
112 SetPageUptodate(page
);
117 void nfs_pageio_init_read(struct nfs_pageio_descriptor
*pgio
,
118 struct inode
*inode
, bool force_mds
,
119 const struct nfs_pgio_completion_ops
*compl_ops
)
121 struct nfs_server
*server
= NFS_SERVER(inode
);
122 const struct nfs_pageio_ops
*pg_ops
= &nfs_pageio_read_ops
;
124 #ifdef CONFIG_NFS_V4_1
125 if (server
->pnfs_curr_ld
&& !force_mds
)
126 pg_ops
= server
->pnfs_curr_ld
->pg_read_ops
;
128 nfs_pageio_init(pgio
, inode
, pg_ops
, compl_ops
, server
->rsize
, 0);
130 EXPORT_SYMBOL_GPL(nfs_pageio_init_read
);
132 void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor
*pgio
)
134 pgio
->pg_ops
= &nfs_pageio_read_ops
;
135 pgio
->pg_bsize
= NFS_SERVER(pgio
->pg_inode
)->rsize
;
137 EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds
);
139 int nfs_readpage_async(struct nfs_open_context
*ctx
, struct inode
*inode
,
142 struct nfs_page
*new;
144 struct nfs_pageio_descriptor pgio
;
146 len
= nfs_page_length(page
);
148 return nfs_return_empty_page(page
);
149 new = nfs_create_request(ctx
, inode
, page
, 0, len
);
154 if (len
< PAGE_CACHE_SIZE
)
155 zero_user_segment(page
, len
, PAGE_CACHE_SIZE
);
157 nfs_pageio_init_read(&pgio
, inode
, false,
158 &nfs_async_read_completion_ops
);
159 nfs_pageio_add_request(&pgio
, new);
160 nfs_pageio_complete(&pgio
);
161 NFS_I(inode
)->read_io
+= pgio
.pg_bytes_written
;
165 static void nfs_readpage_release(struct nfs_page
*req
)
167 struct inode
*d_inode
= req
->wb_context
->dentry
->d_inode
;
169 if (PageUptodate(req
->wb_page
))
170 nfs_readpage_to_fscache(d_inode
, req
->wb_page
, 0);
172 unlock_page(req
->wb_page
);
174 dprintk("NFS: read done (%s/%Lu %d@%Ld)\n",
175 req
->wb_context
->dentry
->d_inode
->i_sb
->s_id
,
176 (unsigned long long)NFS_FILEID(req
->wb_context
->dentry
->d_inode
),
178 (long long)req_offset(req
));
179 nfs_release_request(req
);
182 /* Note io was page aligned */
183 static void nfs_read_completion(struct nfs_pgio_header
*hdr
)
185 unsigned long bytes
= 0;
187 if (test_bit(NFS_IOHDR_REDO
, &hdr
->flags
))
189 while (!list_empty(&hdr
->pages
)) {
190 struct nfs_page
*req
= nfs_list_entry(hdr
->pages
.next
);
191 struct page
*page
= req
->wb_page
;
193 if (test_bit(NFS_IOHDR_EOF
, &hdr
->flags
)) {
194 if (bytes
> hdr
->good_bytes
)
195 zero_user(page
, 0, PAGE_SIZE
);
196 else if (hdr
->good_bytes
- bytes
< PAGE_SIZE
)
197 zero_user_segment(page
,
198 hdr
->good_bytes
& ~PAGE_MASK
,
201 bytes
+= req
->wb_bytes
;
202 if (test_bit(NFS_IOHDR_ERROR
, &hdr
->flags
)) {
203 if (bytes
<= hdr
->good_bytes
)
204 SetPageUptodate(page
);
206 SetPageUptodate(page
);
207 nfs_list_remove_request(req
);
208 nfs_readpage_release(req
);
214 int nfs_initiate_read(struct rpc_clnt
*clnt
,
215 struct nfs_read_data
*data
,
216 const struct rpc_call_ops
*call_ops
, int flags
)
218 struct inode
*inode
= data
->header
->inode
;
219 int swap_flags
= IS_SWAPFILE(inode
) ? NFS_RPC_SWAPFLAGS
: 0;
220 struct rpc_task
*task
;
221 struct rpc_message msg
= {
222 .rpc_argp
= &data
->args
,
223 .rpc_resp
= &data
->res
,
224 .rpc_cred
= data
->header
->cred
,
226 struct rpc_task_setup task_setup_data
= {
230 .callback_ops
= call_ops
,
231 .callback_data
= data
,
232 .workqueue
= nfsiod_workqueue
,
233 .flags
= RPC_TASK_ASYNC
| swap_flags
| flags
,
236 /* Set up the initial task struct. */
237 NFS_PROTO(inode
)->read_setup(data
, &msg
);
239 dprintk("NFS: %5u initiated read call (req %s/%llu, %u bytes @ "
243 (unsigned long long)NFS_FILEID(inode
),
245 (unsigned long long)data
->args
.offset
);
247 task
= rpc_run_task(&task_setup_data
);
249 return PTR_ERR(task
);
253 EXPORT_SYMBOL_GPL(nfs_initiate_read
);
256 * Set up the NFS read request struct
258 static void nfs_read_rpcsetup(struct nfs_read_data
*data
,
259 unsigned int count
, unsigned int offset
)
261 struct nfs_page
*req
= data
->header
->req
;
263 data
->args
.fh
= NFS_FH(data
->header
->inode
);
264 data
->args
.offset
= req_offset(req
) + offset
;
265 data
->args
.pgbase
= req
->wb_pgbase
+ offset
;
266 data
->args
.pages
= data
->pages
.pagevec
;
267 data
->args
.count
= count
;
268 data
->args
.context
= get_nfs_open_context(req
->wb_context
);
269 data
->args
.lock_context
= req
->wb_lock_context
;
271 data
->res
.fattr
= &data
->fattr
;
272 data
->res
.count
= count
;
274 nfs_fattr_init(&data
->fattr
);
277 static int nfs_do_read(struct nfs_read_data
*data
,
278 const struct rpc_call_ops
*call_ops
)
280 struct inode
*inode
= data
->header
->inode
;
282 return nfs_initiate_read(NFS_CLIENT(inode
), data
, call_ops
, 0);
286 nfs_do_multiple_reads(struct list_head
*head
,
287 const struct rpc_call_ops
*call_ops
)
289 struct nfs_read_data
*data
;
292 while (!list_empty(head
)) {
295 data
= list_first_entry(head
, struct nfs_read_data
, list
);
296 list_del_init(&data
->list
);
298 ret2
= nfs_do_read(data
, call_ops
);
306 nfs_async_read_error(struct list_head
*head
)
308 struct nfs_page
*req
;
310 while (!list_empty(head
)) {
311 req
= nfs_list_entry(head
->next
);
312 nfs_list_remove_request(req
);
313 nfs_readpage_release(req
);
317 static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops
= {
318 .error_cleanup
= nfs_async_read_error
,
319 .completion
= nfs_read_completion
,
322 static void nfs_pagein_error(struct nfs_pageio_descriptor
*desc
,
323 struct nfs_pgio_header
*hdr
)
325 set_bit(NFS_IOHDR_REDO
, &hdr
->flags
);
326 while (!list_empty(&hdr
->rpc_list
)) {
327 struct nfs_read_data
*data
= list_first_entry(&hdr
->rpc_list
,
328 struct nfs_read_data
, list
);
329 list_del(&data
->list
);
330 nfs_readdata_release(data
);
332 desc
->pg_completion_ops
->error_cleanup(&desc
->pg_list
);
336 * Generate multiple requests to fill a single page.
338 * We optimize to reduce the number of read operations on the wire. If we
339 * detect that we're reading a page, or an area of a page, that is past the
340 * end of file, we do not generate NFS read operations but just clear the
341 * parts of the page that would have come back zero from the server anyway.
343 * We rely on the cached value of i_size to make this determination; another
344 * client can fill pages on the server past our cached end-of-file, but we
345 * won't see the new data until our attribute cache is updated. This is more
346 * or less conventional NFS client behavior.
348 static int nfs_pagein_multi(struct nfs_pageio_descriptor
*desc
,
349 struct nfs_pgio_header
*hdr
)
351 struct nfs_page
*req
= hdr
->req
;
352 struct page
*page
= req
->wb_page
;
353 struct nfs_read_data
*data
;
354 size_t rsize
= desc
->pg_bsize
, nbytes
;
358 nbytes
= desc
->pg_count
;
360 size_t len
= min(nbytes
,rsize
);
362 data
= nfs_readdata_alloc(hdr
, 1);
364 nfs_pagein_error(desc
, hdr
);
367 data
->pages
.pagevec
[0] = page
;
368 nfs_read_rpcsetup(data
, len
, offset
);
369 list_add(&data
->list
, &hdr
->rpc_list
);
372 } while (nbytes
!= 0);
374 nfs_list_remove_request(req
);
375 nfs_list_add_request(req
, &hdr
->pages
);
376 desc
->pg_rpc_callops
= &nfs_read_common_ops
;
380 static int nfs_pagein_one(struct nfs_pageio_descriptor
*desc
,
381 struct nfs_pgio_header
*hdr
)
383 struct nfs_page
*req
;
385 struct nfs_read_data
*data
;
386 struct list_head
*head
= &desc
->pg_list
;
388 data
= nfs_readdata_alloc(hdr
, nfs_page_array_len(desc
->pg_base
,
391 nfs_pagein_error(desc
, hdr
);
395 pages
= data
->pages
.pagevec
;
396 while (!list_empty(head
)) {
397 req
= nfs_list_entry(head
->next
);
398 nfs_list_remove_request(req
);
399 nfs_list_add_request(req
, &hdr
->pages
);
400 *pages
++ = req
->wb_page
;
403 nfs_read_rpcsetup(data
, desc
->pg_count
, 0);
404 list_add(&data
->list
, &hdr
->rpc_list
);
405 desc
->pg_rpc_callops
= &nfs_read_common_ops
;
409 int nfs_generic_pagein(struct nfs_pageio_descriptor
*desc
,
410 struct nfs_pgio_header
*hdr
)
412 if (desc
->pg_bsize
< PAGE_CACHE_SIZE
)
413 return nfs_pagein_multi(desc
, hdr
);
414 return nfs_pagein_one(desc
, hdr
);
416 EXPORT_SYMBOL_GPL(nfs_generic_pagein
);
418 static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor
*desc
)
420 struct nfs_read_header
*rhdr
;
421 struct nfs_pgio_header
*hdr
;
424 rhdr
= nfs_readhdr_alloc();
426 desc
->pg_completion_ops
->error_cleanup(&desc
->pg_list
);
430 nfs_pgheader_init(desc
, hdr
, nfs_readhdr_free
);
431 atomic_inc(&hdr
->refcnt
);
432 ret
= nfs_generic_pagein(desc
, hdr
);
434 ret
= nfs_do_multiple_reads(&hdr
->rpc_list
,
435 desc
->pg_rpc_callops
);
436 if (atomic_dec_and_test(&hdr
->refcnt
))
437 hdr
->completion_ops
->completion(hdr
);
441 static const struct nfs_pageio_ops nfs_pageio_read_ops
= {
442 .pg_test
= nfs_generic_pg_test
,
443 .pg_doio
= nfs_generic_pg_readpages
,
447 * This is the callback from RPC telling us whether a reply was
448 * received or some error occurred (timeout or socket shutdown).
450 int nfs_readpage_result(struct rpc_task
*task
, struct nfs_read_data
*data
)
452 struct inode
*inode
= data
->header
->inode
;
455 dprintk("NFS: %s: %5u, (status %d)\n", __func__
, task
->tk_pid
,
458 status
= NFS_PROTO(inode
)->read_done(task
, data
);
462 nfs_add_stats(inode
, NFSIOS_SERVERREADBYTES
, data
->res
.count
);
464 if (task
->tk_status
== -ESTALE
) {
465 set_bit(NFS_INO_STALE
, &NFS_I(inode
)->flags
);
466 nfs_mark_for_revalidate(inode
);
471 static void nfs_readpage_retry(struct rpc_task
*task
, struct nfs_read_data
*data
)
473 struct nfs_pgio_args
*argp
= &data
->args
;
474 struct nfs_pgio_res
*resp
= &data
->res
;
476 /* This is a short read! */
477 nfs_inc_stats(data
->header
->inode
, NFSIOS_SHORTREAD
);
478 /* Has the server at least made some progress? */
479 if (resp
->count
== 0) {
480 nfs_set_pgio_error(data
->header
, -EIO
, argp
->offset
);
483 /* Yes, so retry the read at the end of the data */
484 data
->mds_offset
+= resp
->count
;
485 argp
->offset
+= resp
->count
;
486 argp
->pgbase
+= resp
->count
;
487 argp
->count
-= resp
->count
;
488 rpc_restart_call_prepare(task
);
491 static void nfs_readpage_result_common(struct rpc_task
*task
, void *calldata
)
493 struct nfs_read_data
*data
= calldata
;
494 struct nfs_pgio_header
*hdr
= data
->header
;
496 /* Note the only returns of nfs_readpage_result are 0 and -EAGAIN */
497 if (nfs_readpage_result(task
, data
) != 0)
499 if (task
->tk_status
< 0)
500 nfs_set_pgio_error(hdr
, task
->tk_status
, data
->args
.offset
);
501 else if (data
->res
.eof
) {
504 bound
= data
->args
.offset
+ data
->res
.count
;
505 spin_lock(&hdr
->lock
);
506 if (bound
< hdr
->io_start
+ hdr
->good_bytes
) {
507 set_bit(NFS_IOHDR_EOF
, &hdr
->flags
);
508 clear_bit(NFS_IOHDR_ERROR
, &hdr
->flags
);
509 hdr
->good_bytes
= bound
- hdr
->io_start
;
511 spin_unlock(&hdr
->lock
);
512 } else if (data
->res
.count
!= data
->args
.count
)
513 nfs_readpage_retry(task
, data
);
516 static void nfs_readpage_release_common(void *calldata
)
518 nfs_readdata_release(calldata
);
521 void nfs_read_prepare(struct rpc_task
*task
, void *calldata
)
523 struct nfs_read_data
*data
= calldata
;
525 err
= NFS_PROTO(data
->header
->inode
)->read_rpc_prepare(task
, data
);
530 static const struct rpc_call_ops nfs_read_common_ops
= {
531 .rpc_call_prepare
= nfs_read_prepare
,
532 .rpc_call_done
= nfs_readpage_result_common
,
533 .rpc_release
= nfs_readpage_release_common
,
537 * Read a page over NFS.
538 * We read the page synchronously in the following case:
539 * - The error flag is set for this page. This happens only when a
540 * previous async read operation failed.
542 int nfs_readpage(struct file
*file
, struct page
*page
)
544 struct nfs_open_context
*ctx
;
545 struct inode
*inode
= page_file_mapping(page
)->host
;
548 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
549 page
, PAGE_CACHE_SIZE
, page_file_index(page
));
550 nfs_inc_stats(inode
, NFSIOS_VFSREADPAGE
);
551 nfs_add_stats(inode
, NFSIOS_READPAGES
, 1);
554 * Try to flush any pending writes to the file..
556 * NOTE! Because we own the page lock, there cannot
557 * be any new pending writes generated at this point
558 * for this page (other pages can be written to).
560 error
= nfs_wb_page(inode
, page
);
563 if (PageUptodate(page
))
567 if (NFS_STALE(inode
))
572 ctx
= nfs_find_open_context(inode
, NULL
, FMODE_READ
);
576 ctx
= get_nfs_open_context(nfs_file_open_context(file
));
578 if (!IS_SYNC(inode
)) {
579 error
= nfs_readpage_from_fscache(ctx
, inode
, page
);
584 error
= nfs_readpage_async(ctx
, inode
, page
);
587 put_nfs_open_context(ctx
);
594 struct nfs_readdesc
{
595 struct nfs_pageio_descriptor
*pgio
;
596 struct nfs_open_context
*ctx
;
600 readpage_async_filler(void *data
, struct page
*page
)
602 struct nfs_readdesc
*desc
= (struct nfs_readdesc
*)data
;
603 struct inode
*inode
= page_file_mapping(page
)->host
;
604 struct nfs_page
*new;
608 len
= nfs_page_length(page
);
610 return nfs_return_empty_page(page
);
612 new = nfs_create_request(desc
->ctx
, inode
, page
, 0, len
);
616 if (len
< PAGE_CACHE_SIZE
)
617 zero_user_segment(page
, len
, PAGE_CACHE_SIZE
);
618 if (!nfs_pageio_add_request(desc
->pgio
, new)) {
619 error
= desc
->pgio
->pg_error
;
624 error
= PTR_ERR(new);
630 int nfs_readpages(struct file
*filp
, struct address_space
*mapping
,
631 struct list_head
*pages
, unsigned nr_pages
)
633 struct nfs_pageio_descriptor pgio
;
634 struct nfs_readdesc desc
= {
637 struct inode
*inode
= mapping
->host
;
638 unsigned long npages
;
641 dprintk("NFS: nfs_readpages (%s/%Lu %d)\n",
643 (unsigned long long)NFS_FILEID(inode
),
645 nfs_inc_stats(inode
, NFSIOS_VFSREADPAGES
);
647 if (NFS_STALE(inode
))
651 desc
.ctx
= nfs_find_open_context(inode
, NULL
, FMODE_READ
);
652 if (desc
.ctx
== NULL
)
655 desc
.ctx
= get_nfs_open_context(nfs_file_open_context(filp
));
657 /* attempt to read as many of the pages as possible from the cache
658 * - this returns -ENOBUFS immediately if the cookie is negative
660 ret
= nfs_readpages_from_fscache(desc
.ctx
, inode
, mapping
,
663 goto read_complete
; /* all pages were read */
665 nfs_pageio_init_read(&pgio
, inode
, false,
666 &nfs_async_read_completion_ops
);
668 ret
= read_cache_pages(mapping
, pages
, readpage_async_filler
, &desc
);
670 nfs_pageio_complete(&pgio
);
671 NFS_I(inode
)->read_io
+= pgio
.pg_bytes_written
;
672 npages
= (pgio
.pg_bytes_written
+ PAGE_CACHE_SIZE
- 1) >> PAGE_CACHE_SHIFT
;
673 nfs_add_stats(inode
, NFSIOS_READPAGES
, npages
);
675 put_nfs_open_context(desc
.ctx
);
680 int __init
nfs_init_readpagecache(void)
682 nfs_rdata_cachep
= kmem_cache_create("nfs_read_data",
683 sizeof(struct nfs_read_header
),
684 0, SLAB_HWCACHE_ALIGN
,
686 if (nfs_rdata_cachep
== NULL
)
692 void nfs_destroy_readpagecache(void)
694 kmem_cache_destroy(nfs_rdata_cachep
);