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>
28 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
30 static const struct nfs_pageio_ops nfs_pageio_read_ops
;
31 static const struct rpc_call_ops nfs_read_common_ops
;
32 static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops
;
34 static struct kmem_cache
*nfs_rdata_cachep
;
36 struct nfs_read_header
*nfs_readhdr_alloc(void)
38 struct nfs_read_header
*rhdr
;
40 rhdr
= kmem_cache_zalloc(nfs_rdata_cachep
, GFP_KERNEL
);
42 struct nfs_pgio_header
*hdr
= &rhdr
->header
;
44 INIT_LIST_HEAD(&hdr
->pages
);
45 INIT_LIST_HEAD(&hdr
->rpc_list
);
46 spin_lock_init(&hdr
->lock
);
47 atomic_set(&hdr
->refcnt
, 0);
52 static struct nfs_read_data
*nfs_readdata_alloc(struct nfs_pgio_header
*hdr
,
53 unsigned int pagecount
)
55 struct nfs_read_data
*data
, *prealloc
;
57 prealloc
= &container_of(hdr
, struct nfs_read_header
, header
)->rpc_data
;
58 if (prealloc
->header
== NULL
)
61 data
= kzalloc(sizeof(*data
), GFP_KERNEL
);
65 if (nfs_pgarray_set(&data
->pages
, pagecount
)) {
67 atomic_inc(&hdr
->refcnt
);
77 void nfs_readhdr_free(struct nfs_pgio_header
*hdr
)
79 struct nfs_read_header
*rhdr
= container_of(hdr
, struct nfs_read_header
, header
);
81 kmem_cache_free(nfs_rdata_cachep
, rhdr
);
84 void nfs_readdata_release(struct nfs_read_data
*rdata
)
86 struct nfs_pgio_header
*hdr
= rdata
->header
;
87 struct nfs_read_header
*read_header
= container_of(hdr
, struct nfs_read_header
, header
);
89 put_nfs_open_context(rdata
->args
.context
);
90 if (rdata
->pages
.pagevec
!= rdata
->pages
.page_array
)
91 kfree(rdata
->pages
.pagevec
);
92 if (rdata
!= &read_header
->rpc_data
)
96 if (atomic_dec_and_test(&hdr
->refcnt
))
97 hdr
->completion_ops
->completion(hdr
);
101 int nfs_return_empty_page(struct page
*page
)
103 zero_user(page
, 0, PAGE_CACHE_SIZE
);
104 SetPageUptodate(page
);
109 void nfs_pageio_init_read(struct nfs_pageio_descriptor
*pgio
,
111 const struct nfs_pgio_completion_ops
*compl_ops
)
113 nfs_pageio_init(pgio
, inode
, &nfs_pageio_read_ops
, compl_ops
,
114 NFS_SERVER(inode
)->rsize
, 0);
116 EXPORT_SYMBOL_GPL(nfs_pageio_init_read
);
118 void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor
*pgio
)
120 pgio
->pg_ops
= &nfs_pageio_read_ops
;
121 pgio
->pg_bsize
= NFS_SERVER(pgio
->pg_inode
)->rsize
;
123 EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds
);
125 int nfs_readpage_async(struct nfs_open_context
*ctx
, struct inode
*inode
,
128 struct nfs_page
*new;
130 struct nfs_pageio_descriptor pgio
;
132 len
= nfs_page_length(page
);
134 return nfs_return_empty_page(page
);
135 new = nfs_create_request(ctx
, inode
, page
, 0, len
);
140 if (len
< PAGE_CACHE_SIZE
)
141 zero_user_segment(page
, len
, PAGE_CACHE_SIZE
);
143 NFS_PROTO(inode
)->read_pageio_init(&pgio
, inode
, &nfs_async_read_completion_ops
);
144 nfs_pageio_add_request(&pgio
, new);
145 nfs_pageio_complete(&pgio
);
146 NFS_I(inode
)->read_io
+= pgio
.pg_bytes_written
;
150 static void nfs_readpage_release(struct nfs_page
*req
)
152 struct inode
*d_inode
= req
->wb_context
->dentry
->d_inode
;
154 if (PageUptodate(req
->wb_page
))
155 nfs_readpage_to_fscache(d_inode
, req
->wb_page
, 0);
157 unlock_page(req
->wb_page
);
159 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
160 req
->wb_context
->dentry
->d_inode
->i_sb
->s_id
,
161 (long long)NFS_FILEID(req
->wb_context
->dentry
->d_inode
),
163 (long long)req_offset(req
));
164 nfs_release_request(req
);
167 /* Note io was page aligned */
168 static void nfs_read_completion(struct nfs_pgio_header
*hdr
)
170 unsigned long bytes
= 0;
172 if (test_bit(NFS_IOHDR_REDO
, &hdr
->flags
))
174 while (!list_empty(&hdr
->pages
)) {
175 struct nfs_page
*req
= nfs_list_entry(hdr
->pages
.next
);
176 struct page
*page
= req
->wb_page
;
178 if (test_bit(NFS_IOHDR_EOF
, &hdr
->flags
)) {
179 if (bytes
> hdr
->good_bytes
)
180 zero_user(page
, 0, PAGE_SIZE
);
181 else if (hdr
->good_bytes
- bytes
< PAGE_SIZE
)
182 zero_user_segment(page
,
183 hdr
->good_bytes
& ~PAGE_MASK
,
186 bytes
+= req
->wb_bytes
;
187 if (test_bit(NFS_IOHDR_ERROR
, &hdr
->flags
)) {
188 if (bytes
<= hdr
->good_bytes
)
189 SetPageUptodate(page
);
191 SetPageUptodate(page
);
192 nfs_list_remove_request(req
);
193 nfs_readpage_release(req
);
199 int nfs_initiate_read(struct rpc_clnt
*clnt
,
200 struct nfs_read_data
*data
,
201 const struct rpc_call_ops
*call_ops
, int flags
)
203 struct inode
*inode
= data
->header
->inode
;
204 int swap_flags
= IS_SWAPFILE(inode
) ? NFS_RPC_SWAPFLAGS
: 0;
205 struct rpc_task
*task
;
206 struct rpc_message msg
= {
207 .rpc_argp
= &data
->args
,
208 .rpc_resp
= &data
->res
,
209 .rpc_cred
= data
->header
->cred
,
211 struct rpc_task_setup task_setup_data
= {
215 .callback_ops
= call_ops
,
216 .callback_data
= data
,
217 .workqueue
= nfsiod_workqueue
,
218 .flags
= RPC_TASK_ASYNC
| swap_flags
| flags
,
221 /* Set up the initial task struct. */
222 NFS_PROTO(inode
)->read_setup(data
, &msg
);
224 dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ "
228 (long long)NFS_FILEID(inode
),
230 (unsigned long long)data
->args
.offset
);
232 task
= rpc_run_task(&task_setup_data
);
234 return PTR_ERR(task
);
238 EXPORT_SYMBOL_GPL(nfs_initiate_read
);
241 * Set up the NFS read request struct
243 static void nfs_read_rpcsetup(struct nfs_read_data
*data
,
244 unsigned int count
, unsigned int offset
)
246 struct nfs_page
*req
= data
->header
->req
;
248 data
->args
.fh
= NFS_FH(data
->header
->inode
);
249 data
->args
.offset
= req_offset(req
) + offset
;
250 data
->args
.pgbase
= req
->wb_pgbase
+ offset
;
251 data
->args
.pages
= data
->pages
.pagevec
;
252 data
->args
.count
= count
;
253 data
->args
.context
= get_nfs_open_context(req
->wb_context
);
254 data
->args
.lock_context
= req
->wb_lock_context
;
256 data
->res
.fattr
= &data
->fattr
;
257 data
->res
.count
= count
;
259 nfs_fattr_init(&data
->fattr
);
262 static int nfs_do_read(struct nfs_read_data
*data
,
263 const struct rpc_call_ops
*call_ops
)
265 struct inode
*inode
= data
->header
->inode
;
267 return nfs_initiate_read(NFS_CLIENT(inode
), data
, call_ops
, 0);
271 nfs_do_multiple_reads(struct list_head
*head
,
272 const struct rpc_call_ops
*call_ops
)
274 struct nfs_read_data
*data
;
277 while (!list_empty(head
)) {
280 data
= list_first_entry(head
, struct nfs_read_data
, list
);
281 list_del_init(&data
->list
);
283 ret2
= nfs_do_read(data
, call_ops
);
291 nfs_async_read_error(struct list_head
*head
)
293 struct nfs_page
*req
;
295 while (!list_empty(head
)) {
296 req
= nfs_list_entry(head
->next
);
297 nfs_list_remove_request(req
);
298 nfs_readpage_release(req
);
302 static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops
= {
303 .error_cleanup
= nfs_async_read_error
,
304 .completion
= nfs_read_completion
,
307 static void nfs_pagein_error(struct nfs_pageio_descriptor
*desc
,
308 struct nfs_pgio_header
*hdr
)
310 set_bit(NFS_IOHDR_REDO
, &hdr
->flags
);
311 while (!list_empty(&hdr
->rpc_list
)) {
312 struct nfs_read_data
*data
= list_first_entry(&hdr
->rpc_list
,
313 struct nfs_read_data
, list
);
314 list_del(&data
->list
);
315 nfs_readdata_release(data
);
317 desc
->pg_completion_ops
->error_cleanup(&desc
->pg_list
);
321 * Generate multiple requests to fill a single page.
323 * We optimize to reduce the number of read operations on the wire. If we
324 * detect that we're reading a page, or an area of a page, that is past the
325 * end of file, we do not generate NFS read operations but just clear the
326 * parts of the page that would have come back zero from the server anyway.
328 * We rely on the cached value of i_size to make this determination; another
329 * client can fill pages on the server past our cached end-of-file, but we
330 * won't see the new data until our attribute cache is updated. This is more
331 * or less conventional NFS client behavior.
333 static int nfs_pagein_multi(struct nfs_pageio_descriptor
*desc
,
334 struct nfs_pgio_header
*hdr
)
336 struct nfs_page
*req
= hdr
->req
;
337 struct page
*page
= req
->wb_page
;
338 struct nfs_read_data
*data
;
339 size_t rsize
= desc
->pg_bsize
, nbytes
;
343 nbytes
= desc
->pg_count
;
345 size_t len
= min(nbytes
,rsize
);
347 data
= nfs_readdata_alloc(hdr
, 1);
349 nfs_pagein_error(desc
, hdr
);
352 data
->pages
.pagevec
[0] = page
;
353 nfs_read_rpcsetup(data
, len
, offset
);
354 list_add(&data
->list
, &hdr
->rpc_list
);
357 } while (nbytes
!= 0);
359 nfs_list_remove_request(req
);
360 nfs_list_add_request(req
, &hdr
->pages
);
361 desc
->pg_rpc_callops
= &nfs_read_common_ops
;
365 static int nfs_pagein_one(struct nfs_pageio_descriptor
*desc
,
366 struct nfs_pgio_header
*hdr
)
368 struct nfs_page
*req
;
370 struct nfs_read_data
*data
;
371 struct list_head
*head
= &desc
->pg_list
;
373 data
= nfs_readdata_alloc(hdr
, nfs_page_array_len(desc
->pg_base
,
376 nfs_pagein_error(desc
, hdr
);
380 pages
= data
->pages
.pagevec
;
381 while (!list_empty(head
)) {
382 req
= nfs_list_entry(head
->next
);
383 nfs_list_remove_request(req
);
384 nfs_list_add_request(req
, &hdr
->pages
);
385 *pages
++ = req
->wb_page
;
388 nfs_read_rpcsetup(data
, desc
->pg_count
, 0);
389 list_add(&data
->list
, &hdr
->rpc_list
);
390 desc
->pg_rpc_callops
= &nfs_read_common_ops
;
394 int nfs_generic_pagein(struct nfs_pageio_descriptor
*desc
,
395 struct nfs_pgio_header
*hdr
)
397 if (desc
->pg_bsize
< PAGE_CACHE_SIZE
)
398 return nfs_pagein_multi(desc
, hdr
);
399 return nfs_pagein_one(desc
, hdr
);
402 static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor
*desc
)
404 struct nfs_read_header
*rhdr
;
405 struct nfs_pgio_header
*hdr
;
408 rhdr
= nfs_readhdr_alloc();
410 desc
->pg_completion_ops
->error_cleanup(&desc
->pg_list
);
414 nfs_pgheader_init(desc
, hdr
, nfs_readhdr_free
);
415 atomic_inc(&hdr
->refcnt
);
416 ret
= nfs_generic_pagein(desc
, hdr
);
418 ret
= nfs_do_multiple_reads(&hdr
->rpc_list
,
419 desc
->pg_rpc_callops
);
420 if (atomic_dec_and_test(&hdr
->refcnt
))
421 hdr
->completion_ops
->completion(hdr
);
425 static const struct nfs_pageio_ops nfs_pageio_read_ops
= {
426 .pg_test
= nfs_generic_pg_test
,
427 .pg_doio
= nfs_generic_pg_readpages
,
431 * This is the callback from RPC telling us whether a reply was
432 * received or some error occurred (timeout or socket shutdown).
434 int nfs_readpage_result(struct rpc_task
*task
, struct nfs_read_data
*data
)
436 struct inode
*inode
= data
->header
->inode
;
439 dprintk("NFS: %s: %5u, (status %d)\n", __func__
, task
->tk_pid
,
442 status
= NFS_PROTO(inode
)->read_done(task
, data
);
446 nfs_add_stats(inode
, NFSIOS_SERVERREADBYTES
, data
->res
.count
);
448 if (task
->tk_status
== -ESTALE
) {
449 set_bit(NFS_INO_STALE
, &NFS_I(inode
)->flags
);
450 nfs_mark_for_revalidate(inode
);
455 static void nfs_readpage_retry(struct rpc_task
*task
, struct nfs_read_data
*data
)
457 struct nfs_readargs
*argp
= &data
->args
;
458 struct nfs_readres
*resp
= &data
->res
;
460 /* This is a short read! */
461 nfs_inc_stats(data
->header
->inode
, NFSIOS_SHORTREAD
);
462 /* Has the server at least made some progress? */
463 if (resp
->count
== 0) {
464 nfs_set_pgio_error(data
->header
, -EIO
, argp
->offset
);
467 /* Yes, so retry the read at the end of the data */
468 data
->mds_offset
+= resp
->count
;
469 argp
->offset
+= resp
->count
;
470 argp
->pgbase
+= resp
->count
;
471 argp
->count
-= resp
->count
;
472 rpc_restart_call_prepare(task
);
475 static void nfs_readpage_result_common(struct rpc_task
*task
, void *calldata
)
477 struct nfs_read_data
*data
= calldata
;
478 struct nfs_pgio_header
*hdr
= data
->header
;
480 /* Note the only returns of nfs_readpage_result are 0 and -EAGAIN */
481 if (nfs_readpage_result(task
, data
) != 0)
483 if (task
->tk_status
< 0)
484 nfs_set_pgio_error(hdr
, task
->tk_status
, data
->args
.offset
);
485 else if (data
->res
.eof
) {
488 bound
= data
->args
.offset
+ data
->res
.count
;
489 spin_lock(&hdr
->lock
);
490 if (bound
< hdr
->io_start
+ hdr
->good_bytes
) {
491 set_bit(NFS_IOHDR_EOF
, &hdr
->flags
);
492 clear_bit(NFS_IOHDR_ERROR
, &hdr
->flags
);
493 hdr
->good_bytes
= bound
- hdr
->io_start
;
495 spin_unlock(&hdr
->lock
);
496 } else if (data
->res
.count
!= data
->args
.count
)
497 nfs_readpage_retry(task
, data
);
500 static void nfs_readpage_release_common(void *calldata
)
502 nfs_readdata_release(calldata
);
505 void nfs_read_prepare(struct rpc_task
*task
, void *calldata
)
507 struct nfs_read_data
*data
= calldata
;
508 NFS_PROTO(data
->header
->inode
)->read_rpc_prepare(task
, data
);
511 static const struct rpc_call_ops nfs_read_common_ops
= {
512 .rpc_call_prepare
= nfs_read_prepare
,
513 .rpc_call_done
= nfs_readpage_result_common
,
514 .rpc_release
= nfs_readpage_release_common
,
518 * Read a page over NFS.
519 * We read the page synchronously in the following case:
520 * - The error flag is set for this page. This happens only when a
521 * previous async read operation failed.
523 int nfs_readpage(struct file
*file
, struct page
*page
)
525 struct nfs_open_context
*ctx
;
526 struct inode
*inode
= page
->mapping
->host
;
529 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
530 page
, PAGE_CACHE_SIZE
, page
->index
);
531 nfs_inc_stats(inode
, NFSIOS_VFSREADPAGE
);
532 nfs_add_stats(inode
, NFSIOS_READPAGES
, 1);
535 * Try to flush any pending writes to the file..
537 * NOTE! Because we own the page lock, there cannot
538 * be any new pending writes generated at this point
539 * for this page (other pages can be written to).
541 error
= nfs_wb_page(inode
, page
);
544 if (PageUptodate(page
))
548 if (NFS_STALE(inode
))
553 ctx
= nfs_find_open_context(inode
, NULL
, FMODE_READ
);
557 ctx
= get_nfs_open_context(nfs_file_open_context(file
));
559 if (!IS_SYNC(inode
)) {
560 error
= nfs_readpage_from_fscache(ctx
, inode
, page
);
565 error
= nfs_readpage_async(ctx
, inode
, page
);
568 put_nfs_open_context(ctx
);
575 struct nfs_readdesc
{
576 struct nfs_pageio_descriptor
*pgio
;
577 struct nfs_open_context
*ctx
;
581 readpage_async_filler(void *data
, struct page
*page
)
583 struct nfs_readdesc
*desc
= (struct nfs_readdesc
*)data
;
584 struct inode
*inode
= page
->mapping
->host
;
585 struct nfs_page
*new;
589 len
= nfs_page_length(page
);
591 return nfs_return_empty_page(page
);
593 new = nfs_create_request(desc
->ctx
, inode
, page
, 0, len
);
597 if (len
< PAGE_CACHE_SIZE
)
598 zero_user_segment(page
, len
, PAGE_CACHE_SIZE
);
599 if (!nfs_pageio_add_request(desc
->pgio
, new)) {
600 error
= desc
->pgio
->pg_error
;
605 error
= PTR_ERR(new);
611 int nfs_readpages(struct file
*filp
, struct address_space
*mapping
,
612 struct list_head
*pages
, unsigned nr_pages
)
614 struct nfs_pageio_descriptor pgio
;
615 struct nfs_readdesc desc
= {
618 struct inode
*inode
= mapping
->host
;
619 unsigned long npages
;
622 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
624 (long long)NFS_FILEID(inode
),
626 nfs_inc_stats(inode
, NFSIOS_VFSREADPAGES
);
628 if (NFS_STALE(inode
))
632 desc
.ctx
= nfs_find_open_context(inode
, NULL
, FMODE_READ
);
633 if (desc
.ctx
== NULL
)
636 desc
.ctx
= get_nfs_open_context(nfs_file_open_context(filp
));
638 /* attempt to read as many of the pages as possible from the cache
639 * - this returns -ENOBUFS immediately if the cookie is negative
641 ret
= nfs_readpages_from_fscache(desc
.ctx
, inode
, mapping
,
644 goto read_complete
; /* all pages were read */
646 NFS_PROTO(inode
)->read_pageio_init(&pgio
, inode
, &nfs_async_read_completion_ops
);
648 ret
= read_cache_pages(mapping
, pages
, readpage_async_filler
, &desc
);
650 nfs_pageio_complete(&pgio
);
651 NFS_I(inode
)->read_io
+= pgio
.pg_bytes_written
;
652 npages
= (pgio
.pg_bytes_written
+ PAGE_CACHE_SIZE
- 1) >> PAGE_CACHE_SHIFT
;
653 nfs_add_stats(inode
, NFSIOS_READPAGES
, npages
);
655 put_nfs_open_context(desc
.ctx
);
660 int __init
nfs_init_readpagecache(void)
662 nfs_rdata_cachep
= kmem_cache_create("nfs_read_data",
663 sizeof(struct nfs_read_header
),
664 0, SLAB_HWCACHE_ALIGN
,
666 if (nfs_rdata_cachep
== NULL
)
672 void nfs_destroy_readpagecache(void)
674 kmem_cache_destroy(nfs_rdata_cachep
);