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/smp_lock.h>
23 #include <asm/system.h>
28 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
30 static int nfs_pagein_multi(struct inode
*, struct list_head
*, unsigned int, size_t, int);
31 static int nfs_pagein_one(struct inode
*, struct list_head
*, unsigned int, size_t, int);
32 static const struct rpc_call_ops nfs_read_partial_ops
;
33 static const struct rpc_call_ops nfs_read_full_ops
;
35 static struct kmem_cache
*nfs_rdata_cachep
;
36 static mempool_t
*nfs_rdata_mempool
;
38 #define MIN_POOL_READ (32)
40 struct nfs_read_data
*nfs_readdata_alloc(unsigned int pagecount
)
42 struct nfs_read_data
*p
= mempool_alloc(nfs_rdata_mempool
, GFP_NOFS
);
45 memset(p
, 0, sizeof(*p
));
46 INIT_LIST_HEAD(&p
->pages
);
47 p
->npages
= pagecount
;
48 if (pagecount
<= ARRAY_SIZE(p
->page_array
))
49 p
->pagevec
= p
->page_array
;
51 p
->pagevec
= kcalloc(pagecount
, sizeof(struct page
*), GFP_NOFS
);
53 mempool_free(p
, nfs_rdata_mempool
);
61 static void nfs_readdata_rcu_free(struct rcu_head
*head
)
63 struct nfs_read_data
*p
= container_of(head
, struct nfs_read_data
, task
.u
.tk_rcu
);
64 if (p
&& (p
->pagevec
!= &p
->page_array
[0]))
66 mempool_free(p
, nfs_rdata_mempool
);
69 static void nfs_readdata_free(struct nfs_read_data
*rdata
)
71 call_rcu_bh(&rdata
->task
.u
.tk_rcu
, nfs_readdata_rcu_free
);
74 void nfs_readdata_release(void *data
)
76 nfs_readdata_free(data
);
80 int nfs_return_empty_page(struct page
*page
)
82 zero_user_page(page
, 0, PAGE_CACHE_SIZE
, KM_USER0
);
83 SetPageUptodate(page
);
88 static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data
*data
)
90 unsigned int remainder
= data
->args
.count
- data
->res
.count
;
91 unsigned int base
= data
->args
.pgbase
+ data
->res
.count
;
95 if (data
->res
.eof
== 0 || remainder
== 0)
98 * Note: "remainder" can never be negative, since we check for
99 * this in the XDR code.
101 pages
= &data
->args
.pages
[base
>> PAGE_CACHE_SHIFT
];
102 base
&= ~PAGE_CACHE_MASK
;
103 pglen
= PAGE_CACHE_SIZE
- base
;
105 if (remainder
<= pglen
) {
106 zero_user_page(*pages
, base
, remainder
, KM_USER0
);
109 zero_user_page(*pages
, base
, pglen
, KM_USER0
);
112 pglen
= PAGE_CACHE_SIZE
;
117 static int nfs_readpage_async(struct nfs_open_context
*ctx
, struct inode
*inode
,
120 LIST_HEAD(one_request
);
121 struct nfs_page
*new;
124 len
= nfs_page_length(page
);
126 return nfs_return_empty_page(page
);
127 new = nfs_create_request(ctx
, inode
, page
, 0, len
);
132 if (len
< PAGE_CACHE_SIZE
)
133 zero_user_page(page
, len
, PAGE_CACHE_SIZE
- len
, KM_USER0
);
135 nfs_list_add_request(new, &one_request
);
136 if (NFS_SERVER(inode
)->rsize
< PAGE_CACHE_SIZE
)
137 nfs_pagein_multi(inode
, &one_request
, 1, len
, 0);
139 nfs_pagein_one(inode
, &one_request
, 1, len
, 0);
143 static void nfs_readpage_release(struct nfs_page
*req
)
145 unlock_page(req
->wb_page
);
147 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
148 req
->wb_context
->path
.dentry
->d_inode
->i_sb
->s_id
,
149 (long long)NFS_FILEID(req
->wb_context
->path
.dentry
->d_inode
),
151 (long long)req_offset(req
));
152 nfs_clear_request(req
);
153 nfs_release_request(req
);
156 static void nfs_execute_read(struct nfs_read_data
*data
)
158 struct rpc_clnt
*clnt
= NFS_CLIENT(data
->inode
);
161 rpc_clnt_sigmask(clnt
, &oldset
);
162 rpc_execute(&data
->task
);
163 rpc_clnt_sigunmask(clnt
, &oldset
);
167 * Set up the NFS read request struct
169 static void nfs_read_rpcsetup(struct nfs_page
*req
, struct nfs_read_data
*data
,
170 const struct rpc_call_ops
*call_ops
,
171 unsigned int count
, unsigned int offset
)
173 struct inode
*inode
= req
->wb_context
->path
.dentry
->d_inode
;
174 int swap_flags
= IS_SWAPFILE(inode
) ? NFS_RPC_SWAPFLAGS
: 0;
175 struct rpc_message msg
= {
176 .rpc_argp
= &data
->args
,
177 .rpc_resp
= &data
->res
,
178 .rpc_cred
= req
->wb_context
->cred
,
180 struct rpc_task_setup task_setup_data
= {
181 .rpc_client
= NFS_CLIENT(inode
),
183 .callback_ops
= call_ops
,
184 .callback_data
= data
,
185 .flags
= RPC_TASK_ASYNC
| swap_flags
,
190 data
->cred
= msg
.rpc_cred
;
192 data
->args
.fh
= NFS_FH(inode
);
193 data
->args
.offset
= req_offset(req
) + offset
;
194 data
->args
.pgbase
= req
->wb_pgbase
+ offset
;
195 data
->args
.pages
= data
->pagevec
;
196 data
->args
.count
= count
;
197 data
->args
.context
= req
->wb_context
;
199 data
->res
.fattr
= &data
->fattr
;
200 data
->res
.count
= count
;
202 nfs_fattr_init(&data
->fattr
);
204 /* Set up the initial task struct. */
205 NFS_PROTO(inode
)->read_setup(data
, &msg
);
206 rpc_init_task(&data
->task
, &task_setup_data
);
208 dprintk("NFS: %5u initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
211 (long long)NFS_FILEID(inode
),
213 (unsigned long long)data
->args
.offset
);
215 nfs_execute_read(data
);
219 nfs_async_read_error(struct list_head
*head
)
221 struct nfs_page
*req
;
223 while (!list_empty(head
)) {
224 req
= nfs_list_entry(head
->next
);
225 nfs_list_remove_request(req
);
226 SetPageError(req
->wb_page
);
227 nfs_readpage_release(req
);
232 * Generate multiple requests to fill a single page.
234 * We optimize to reduce the number of read operations on the wire. If we
235 * detect that we're reading a page, or an area of a page, that is past the
236 * end of file, we do not generate NFS read operations but just clear the
237 * parts of the page that would have come back zero from the server anyway.
239 * We rely on the cached value of i_size to make this determination; another
240 * client can fill pages on the server past our cached end-of-file, but we
241 * won't see the new data until our attribute cache is updated. This is more
242 * or less conventional NFS client behavior.
244 static int nfs_pagein_multi(struct inode
*inode
, struct list_head
*head
, unsigned int npages
, size_t count
, int flags
)
246 struct nfs_page
*req
= nfs_list_entry(head
->next
);
247 struct page
*page
= req
->wb_page
;
248 struct nfs_read_data
*data
;
249 size_t rsize
= NFS_SERVER(inode
)->rsize
, nbytes
;
254 nfs_list_remove_request(req
);
258 size_t len
= min(nbytes
,rsize
);
260 data
= nfs_readdata_alloc(1);
263 INIT_LIST_HEAD(&data
->pages
);
264 list_add(&data
->pages
, &list
);
267 } while(nbytes
!= 0);
268 atomic_set(&req
->wb_complete
, requests
);
270 ClearPageError(page
);
274 data
= list_entry(list
.next
, struct nfs_read_data
, pages
);
275 list_del_init(&data
->pages
);
277 data
->pagevec
[0] = page
;
281 nfs_read_rpcsetup(req
, data
, &nfs_read_partial_ops
,
285 } while (nbytes
!= 0);
290 while (!list_empty(&list
)) {
291 data
= list_entry(list
.next
, struct nfs_read_data
, pages
);
292 list_del(&data
->pages
);
293 nfs_readdata_free(data
);
296 nfs_readpage_release(req
);
300 static int nfs_pagein_one(struct inode
*inode
, struct list_head
*head
, unsigned int npages
, size_t count
, int flags
)
302 struct nfs_page
*req
;
304 struct nfs_read_data
*data
;
306 data
= nfs_readdata_alloc(npages
);
310 INIT_LIST_HEAD(&data
->pages
);
311 pages
= data
->pagevec
;
312 while (!list_empty(head
)) {
313 req
= nfs_list_entry(head
->next
);
314 nfs_list_remove_request(req
);
315 nfs_list_add_request(req
, &data
->pages
);
316 ClearPageError(req
->wb_page
);
317 *pages
++ = req
->wb_page
;
319 req
= nfs_list_entry(data
->pages
.next
);
321 nfs_read_rpcsetup(req
, data
, &nfs_read_full_ops
, count
, 0);
324 nfs_async_read_error(head
);
329 * This is the callback from RPC telling us whether a reply was
330 * received or some error occurred (timeout or socket shutdown).
332 int nfs_readpage_result(struct rpc_task
*task
, struct nfs_read_data
*data
)
336 dprintk("NFS: %s: %5u, (status %d)\n", __FUNCTION__
, task
->tk_pid
,
339 status
= NFS_PROTO(data
->inode
)->read_done(task
, data
);
343 nfs_add_stats(data
->inode
, NFSIOS_SERVERREADBYTES
, data
->res
.count
);
345 if (task
->tk_status
== -ESTALE
) {
346 set_bit(NFS_INO_STALE
, &NFS_FLAGS(data
->inode
));
347 nfs_mark_for_revalidate(data
->inode
);
352 static int nfs_readpage_retry(struct rpc_task
*task
, struct nfs_read_data
*data
)
354 struct nfs_readargs
*argp
= &data
->args
;
355 struct nfs_readres
*resp
= &data
->res
;
357 if (resp
->eof
|| resp
->count
== argp
->count
)
360 /* This is a short read! */
361 nfs_inc_stats(data
->inode
, NFSIOS_SHORTREAD
);
362 /* Has the server at least made some progress? */
363 if (resp
->count
== 0)
366 /* Yes, so retry the read at the end of the data */
367 argp
->offset
+= resp
->count
;
368 argp
->pgbase
+= resp
->count
;
369 argp
->count
-= resp
->count
;
370 rpc_restart_call(task
);
375 * Handle a read reply that fills part of a page.
377 static void nfs_readpage_result_partial(struct rpc_task
*task
, void *calldata
)
379 struct nfs_read_data
*data
= calldata
;
380 struct nfs_page
*req
= data
->req
;
381 struct page
*page
= req
->wb_page
;
383 if (nfs_readpage_result(task
, data
) != 0)
386 if (likely(task
->tk_status
>= 0)) {
387 nfs_readpage_truncate_uninitialised_page(data
);
388 if (nfs_readpage_retry(task
, data
) != 0)
391 if (unlikely(task
->tk_status
< 0))
393 if (atomic_dec_and_test(&req
->wb_complete
)) {
394 if (!PageError(page
))
395 SetPageUptodate(page
);
396 nfs_readpage_release(req
);
400 static const struct rpc_call_ops nfs_read_partial_ops
= {
401 .rpc_call_done
= nfs_readpage_result_partial
,
402 .rpc_release
= nfs_readdata_release
,
405 static void nfs_readpage_set_pages_uptodate(struct nfs_read_data
*data
)
407 unsigned int count
= data
->res
.count
;
408 unsigned int base
= data
->args
.pgbase
;
412 count
= data
->args
.count
;
413 if (unlikely(count
== 0))
415 pages
= &data
->args
.pages
[base
>> PAGE_CACHE_SHIFT
];
416 base
&= ~PAGE_CACHE_MASK
;
418 for (;count
>= PAGE_CACHE_SIZE
; count
-= PAGE_CACHE_SIZE
, pages
++)
419 SetPageUptodate(*pages
);
422 /* Was this a short read? */
423 if (data
->res
.eof
|| data
->res
.count
== data
->args
.count
)
424 SetPageUptodate(*pages
);
428 * This is the callback from RPC telling us whether a reply was
429 * received or some error occurred (timeout or socket shutdown).
431 static void nfs_readpage_result_full(struct rpc_task
*task
, void *calldata
)
433 struct nfs_read_data
*data
= calldata
;
435 if (nfs_readpage_result(task
, data
) != 0)
438 * Note: nfs_readpage_retry may change the values of
439 * data->args. In the multi-page case, we therefore need
440 * to ensure that we call nfs_readpage_set_pages_uptodate()
443 if (likely(task
->tk_status
>= 0)) {
444 nfs_readpage_truncate_uninitialised_page(data
);
445 nfs_readpage_set_pages_uptodate(data
);
446 if (nfs_readpage_retry(task
, data
) != 0)
449 while (!list_empty(&data
->pages
)) {
450 struct nfs_page
*req
= nfs_list_entry(data
->pages
.next
);
452 nfs_list_remove_request(req
);
453 nfs_readpage_release(req
);
457 static const struct rpc_call_ops nfs_read_full_ops
= {
458 .rpc_call_done
= nfs_readpage_result_full
,
459 .rpc_release
= nfs_readdata_release
,
463 * Read a page over NFS.
464 * We read the page synchronously in the following case:
465 * - The error flag is set for this page. This happens only when a
466 * previous async read operation failed.
468 int nfs_readpage(struct file
*file
, struct page
*page
)
470 struct nfs_open_context
*ctx
;
471 struct inode
*inode
= page
->mapping
->host
;
474 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
475 page
, PAGE_CACHE_SIZE
, page
->index
);
476 nfs_inc_stats(inode
, NFSIOS_VFSREADPAGE
);
477 nfs_add_stats(inode
, NFSIOS_READPAGES
, 1);
480 * Try to flush any pending writes to the file..
482 * NOTE! Because we own the page lock, there cannot
483 * be any new pending writes generated at this point
484 * for this page (other pages can be written to).
486 error
= nfs_wb_page(inode
, page
);
489 if (PageUptodate(page
))
493 if (NFS_STALE(inode
))
498 ctx
= nfs_find_open_context(inode
, NULL
, FMODE_READ
);
502 ctx
= get_nfs_open_context(nfs_file_open_context(file
));
504 error
= nfs_readpage_async(ctx
, inode
, page
);
506 put_nfs_open_context(ctx
);
513 struct nfs_readdesc
{
514 struct nfs_pageio_descriptor
*pgio
;
515 struct nfs_open_context
*ctx
;
519 readpage_async_filler(void *data
, struct page
*page
)
521 struct nfs_readdesc
*desc
= (struct nfs_readdesc
*)data
;
522 struct inode
*inode
= page
->mapping
->host
;
523 struct nfs_page
*new;
527 error
= nfs_wb_page(inode
, page
);
530 if (PageUptodate(page
))
533 len
= nfs_page_length(page
);
535 return nfs_return_empty_page(page
);
537 new = nfs_create_request(desc
->ctx
, inode
, page
, 0, len
);
541 if (len
< PAGE_CACHE_SIZE
)
542 zero_user_page(page
, len
, PAGE_CACHE_SIZE
- len
, KM_USER0
);
543 nfs_pageio_add_request(desc
->pgio
, new);
546 error
= PTR_ERR(new);
553 int nfs_readpages(struct file
*filp
, struct address_space
*mapping
,
554 struct list_head
*pages
, unsigned nr_pages
)
556 struct nfs_pageio_descriptor pgio
;
557 struct nfs_readdesc desc
= {
560 struct inode
*inode
= mapping
->host
;
561 struct nfs_server
*server
= NFS_SERVER(inode
);
562 size_t rsize
= server
->rsize
;
563 unsigned long npages
;
566 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
568 (long long)NFS_FILEID(inode
),
570 nfs_inc_stats(inode
, NFSIOS_VFSREADPAGES
);
572 if (NFS_STALE(inode
))
576 desc
.ctx
= nfs_find_open_context(inode
, NULL
, FMODE_READ
);
577 if (desc
.ctx
== NULL
)
580 desc
.ctx
= get_nfs_open_context(nfs_file_open_context(filp
));
581 if (rsize
< PAGE_CACHE_SIZE
)
582 nfs_pageio_init(&pgio
, inode
, nfs_pagein_multi
, rsize
, 0);
584 nfs_pageio_init(&pgio
, inode
, nfs_pagein_one
, rsize
, 0);
586 ret
= read_cache_pages(mapping
, pages
, readpage_async_filler
, &desc
);
588 nfs_pageio_complete(&pgio
);
589 npages
= (pgio
.pg_bytes_written
+ PAGE_CACHE_SIZE
- 1) >> PAGE_CACHE_SHIFT
;
590 nfs_add_stats(inode
, NFSIOS_READPAGES
, npages
);
591 put_nfs_open_context(desc
.ctx
);
596 int __init
nfs_init_readpagecache(void)
598 nfs_rdata_cachep
= kmem_cache_create("nfs_read_data",
599 sizeof(struct nfs_read_data
),
600 0, SLAB_HWCACHE_ALIGN
,
602 if (nfs_rdata_cachep
== NULL
)
605 nfs_rdata_mempool
= mempool_create_slab_pool(MIN_POOL_READ
,
607 if (nfs_rdata_mempool
== NULL
)
613 void nfs_destroy_readpagecache(void)
615 mempool_destroy(nfs_rdata_mempool
);
616 kmem_cache_destroy(nfs_rdata_cachep
);