Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/nfs/read.c | |
3 | * | |
4 | * Block I/O for NFS | |
5 | * | |
6 | * Partial copy of Linus' read cache modifications to fs/nfs/file.c | |
7 | * modified for async RPC by okir@monad.swb.de | |
8 | * | |
9 | * We do an ugly hack here in order to return proper error codes to the | |
10 | * user program when a read request failed: since generic_file_read | |
11 | * only checks the return value of inode->i_op->readpage() which is always 0 | |
12 | * for async RPC, we set the error bit of the page to 1 when an error occurs, | |
13 | * and make nfs_readpage transmit requests synchronously when encountering this. | |
14 | * This is only a small problem, though, since we now retry all operations | |
15 | * within the RPC code when root squashing is suspected. | |
16 | */ | |
17 | ||
1da177e4 LT |
18 | #include <linux/time.h> |
19 | #include <linux/kernel.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/fcntl.h> | |
22 | #include <linux/stat.h> | |
23 | #include <linux/mm.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/pagemap.h> | |
26 | #include <linux/sunrpc/clnt.h> | |
27 | #include <linux/nfs_fs.h> | |
28 | #include <linux/nfs_page.h> | |
29 | #include <linux/smp_lock.h> | |
30 | ||
31 | #include <asm/system.h> | |
32 | ||
49a70f27 | 33 | #include "internal.h" |
91d5b470 CL |
34 | #include "iostat.h" |
35 | ||
1da177e4 LT |
36 | #define NFSDBG_FACILITY NFSDBG_PAGECACHE |
37 | ||
38 | static int nfs_pagein_one(struct list_head *, struct inode *); | |
ec06c096 TM |
39 | static const struct rpc_call_ops nfs_read_partial_ops; |
40 | static const struct rpc_call_ops nfs_read_full_ops; | |
1da177e4 | 41 | |
e18b890b | 42 | static struct kmem_cache *nfs_rdata_cachep; |
3feb2d49 | 43 | static mempool_t *nfs_rdata_mempool; |
1da177e4 LT |
44 | |
45 | #define MIN_POOL_READ (32) | |
46 | ||
e9f7bee1 | 47 | struct nfs_read_data *nfs_readdata_alloc(size_t len) |
3feb2d49 | 48 | { |
e9f7bee1 | 49 | unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
e6b4f8da | 50 | struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, GFP_NOFS); |
3feb2d49 TM |
51 | |
52 | if (p) { | |
53 | memset(p, 0, sizeof(*p)); | |
54 | INIT_LIST_HEAD(&p->pages); | |
e9f7bee1 | 55 | p->npages = pagecount; |
0d0b5cb3 CL |
56 | if (pagecount <= ARRAY_SIZE(p->page_array)) |
57 | p->pagevec = p->page_array; | |
3feb2d49 | 58 | else { |
0d0b5cb3 CL |
59 | p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS); |
60 | if (!p->pagevec) { | |
3feb2d49 TM |
61 | mempool_free(p, nfs_rdata_mempool); |
62 | p = NULL; | |
63 | } | |
64 | } | |
65 | } | |
66 | return p; | |
67 | } | |
68 | ||
8aca67f0 | 69 | static void nfs_readdata_rcu_free(struct rcu_head *head) |
3feb2d49 | 70 | { |
8aca67f0 | 71 | struct nfs_read_data *p = container_of(head, struct nfs_read_data, task.u.tk_rcu); |
3feb2d49 TM |
72 | if (p && (p->pagevec != &p->page_array[0])) |
73 | kfree(p->pagevec); | |
74 | mempool_free(p, nfs_rdata_mempool); | |
75 | } | |
76 | ||
8aca67f0 TM |
77 | static void nfs_readdata_free(struct nfs_read_data *rdata) |
78 | { | |
79 | call_rcu_bh(&rdata->task.u.tk_rcu, nfs_readdata_rcu_free); | |
80 | } | |
81 | ||
963d8fe5 | 82 | void nfs_readdata_release(void *data) |
1da177e4 | 83 | { |
1da177e4 LT |
84 | nfs_readdata_free(data); |
85 | } | |
86 | ||
1da177e4 LT |
87 | static |
88 | int nfs_return_empty_page(struct page *page) | |
89 | { | |
90 | memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE); | |
91 | SetPageUptodate(page); | |
92 | unlock_page(page); | |
93 | return 0; | |
94 | } | |
95 | ||
1de3fc12 TM |
96 | static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data) |
97 | { | |
98 | unsigned int remainder = data->args.count - data->res.count; | |
99 | unsigned int base = data->args.pgbase + data->res.count; | |
100 | unsigned int pglen; | |
101 | struct page **pages; | |
102 | ||
103 | if (data->res.eof == 0 || remainder == 0) | |
104 | return; | |
105 | /* | |
106 | * Note: "remainder" can never be negative, since we check for | |
107 | * this in the XDR code. | |
108 | */ | |
109 | pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; | |
110 | base &= ~PAGE_CACHE_MASK; | |
111 | pglen = PAGE_CACHE_SIZE - base; | |
79558f36 TM |
112 | for (;;) { |
113 | if (remainder <= pglen) { | |
114 | memclear_highpage_flush(*pages, base, remainder); | |
115 | break; | |
116 | } | |
1de3fc12 | 117 | memclear_highpage_flush(*pages, base, pglen); |
79558f36 TM |
118 | pages++; |
119 | remainder -= pglen; | |
120 | pglen = PAGE_CACHE_SIZE; | |
121 | base = 0; | |
122 | } | |
1de3fc12 TM |
123 | } |
124 | ||
1da177e4 LT |
125 | /* |
126 | * Read a page synchronously. | |
127 | */ | |
128 | static int nfs_readpage_sync(struct nfs_open_context *ctx, struct inode *inode, | |
129 | struct page *page) | |
130 | { | |
131 | unsigned int rsize = NFS_SERVER(inode)->rsize; | |
132 | unsigned int count = PAGE_CACHE_SIZE; | |
cf1308ff | 133 | int result = -ENOMEM; |
1da177e4 LT |
134 | struct nfs_read_data *rdata; |
135 | ||
e9f7bee1 | 136 | rdata = nfs_readdata_alloc(count); |
1da177e4 | 137 | if (!rdata) |
cf1308ff | 138 | goto out_unlock; |
1da177e4 LT |
139 | |
140 | memset(rdata, 0, sizeof(*rdata)); | |
141 | rdata->flags = (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0); | |
142 | rdata->cred = ctx->cred; | |
143 | rdata->inode = inode; | |
144 | INIT_LIST_HEAD(&rdata->pages); | |
145 | rdata->args.fh = NFS_FH(inode); | |
146 | rdata->args.context = ctx; | |
147 | rdata->args.pages = &page; | |
148 | rdata->args.pgbase = 0UL; | |
149 | rdata->args.count = rsize; | |
150 | rdata->res.fattr = &rdata->fattr; | |
151 | ||
152 | dprintk("NFS: nfs_readpage_sync(%p)\n", page); | |
153 | ||
154 | /* | |
155 | * This works now because the socket layer never tries to DMA | |
156 | * into this buffer directly. | |
157 | */ | |
158 | do { | |
159 | if (count < rsize) | |
160 | rdata->args.count = count; | |
161 | rdata->res.count = rdata->args.count; | |
162 | rdata->args.offset = page_offset(page) + rdata->args.pgbase; | |
163 | ||
164 | dprintk("NFS: nfs_proc_read(%s, (%s/%Ld), %Lu, %u)\n", | |
54ceac45 | 165 | NFS_SERVER(inode)->nfs_client->cl_hostname, |
1da177e4 LT |
166 | inode->i_sb->s_id, |
167 | (long long)NFS_FILEID(inode), | |
168 | (unsigned long long)rdata->args.pgbase, | |
169 | rdata->args.count); | |
170 | ||
171 | lock_kernel(); | |
172 | result = NFS_PROTO(inode)->read(rdata); | |
173 | unlock_kernel(); | |
174 | ||
175 | /* | |
176 | * Even if we had a partial success we can't mark the page | |
177 | * cache valid. | |
178 | */ | |
179 | if (result < 0) { | |
180 | if (result == -EISDIR) | |
181 | result = -EINVAL; | |
182 | goto io_error; | |
183 | } | |
184 | count -= result; | |
185 | rdata->args.pgbase += result; | |
91d5b470 CL |
186 | nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, result); |
187 | ||
1da177e4 LT |
188 | /* Note: result == 0 should only happen if we're caching |
189 | * a write that extends the file and punches a hole. | |
190 | */ | |
191 | if (rdata->res.eof != 0 || result == 0) | |
192 | break; | |
193 | } while (count); | |
dc59250c | 194 | spin_lock(&inode->i_lock); |
55296809 | 195 | NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME; |
dc59250c | 196 | spin_unlock(&inode->i_lock); |
1da177e4 | 197 | |
7a524111 | 198 | if (rdata->res.eof || rdata->res.count == rdata->args.count) { |
1de3fc12 | 199 | SetPageUptodate(page); |
7a524111 TM |
200 | if (rdata->res.eof && count != 0) |
201 | memclear_highpage_flush(page, rdata->args.pgbase, count); | |
202 | } | |
1da177e4 LT |
203 | result = 0; |
204 | ||
205 | io_error: | |
1da177e4 | 206 | nfs_readdata_free(rdata); |
cf1308ff TM |
207 | out_unlock: |
208 | unlock_page(page); | |
1da177e4 LT |
209 | return result; |
210 | } | |
211 | ||
212 | static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, | |
213 | struct page *page) | |
214 | { | |
215 | LIST_HEAD(one_request); | |
216 | struct nfs_page *new; | |
217 | unsigned int len; | |
218 | ||
49a70f27 | 219 | len = nfs_page_length(page); |
1da177e4 LT |
220 | if (len == 0) |
221 | return nfs_return_empty_page(page); | |
222 | new = nfs_create_request(ctx, inode, page, 0, len); | |
223 | if (IS_ERR(new)) { | |
224 | unlock_page(page); | |
225 | return PTR_ERR(new); | |
226 | } | |
227 | if (len < PAGE_CACHE_SIZE) | |
228 | memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len); | |
229 | ||
1da177e4 LT |
230 | nfs_list_add_request(new, &one_request); |
231 | nfs_pagein_one(&one_request, inode); | |
232 | return 0; | |
233 | } | |
234 | ||
235 | static void nfs_readpage_release(struct nfs_page *req) | |
236 | { | |
237 | unlock_page(req->wb_page); | |
238 | ||
1da177e4 LT |
239 | dprintk("NFS: read done (%s/%Ld %d@%Ld)\n", |
240 | req->wb_context->dentry->d_inode->i_sb->s_id, | |
241 | (long long)NFS_FILEID(req->wb_context->dentry->d_inode), | |
242 | req->wb_bytes, | |
243 | (long long)req_offset(req)); | |
10d2c46f NW |
244 | nfs_clear_request(req); |
245 | nfs_release_request(req); | |
1da177e4 LT |
246 | } |
247 | ||
248 | /* | |
249 | * Set up the NFS read request struct | |
250 | */ | |
251 | static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data, | |
ec06c096 | 252 | const struct rpc_call_ops *call_ops, |
1da177e4 LT |
253 | unsigned int count, unsigned int offset) |
254 | { | |
255 | struct inode *inode; | |
ec06c096 | 256 | int flags; |
1da177e4 LT |
257 | |
258 | data->req = req; | |
259 | data->inode = inode = req->wb_context->dentry->d_inode; | |
260 | data->cred = req->wb_context->cred; | |
261 | ||
262 | data->args.fh = NFS_FH(inode); | |
263 | data->args.offset = req_offset(req) + offset; | |
264 | data->args.pgbase = req->wb_pgbase + offset; | |
265 | data->args.pages = data->pagevec; | |
266 | data->args.count = count; | |
267 | data->args.context = req->wb_context; | |
268 | ||
269 | data->res.fattr = &data->fattr; | |
270 | data->res.count = count; | |
271 | data->res.eof = 0; | |
0e574af1 | 272 | nfs_fattr_init(&data->fattr); |
1da177e4 | 273 | |
ec06c096 TM |
274 | /* Set up the initial task struct. */ |
275 | flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0); | |
276 | rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data); | |
1da177e4 LT |
277 | NFS_PROTO(inode)->read_setup(data); |
278 | ||
279 | data->task.tk_cookie = (unsigned long)inode; | |
1da177e4 LT |
280 | |
281 | dprintk("NFS: %4d initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n", | |
282 | data->task.tk_pid, | |
283 | inode->i_sb->s_id, | |
284 | (long long)NFS_FILEID(inode), | |
285 | count, | |
286 | (unsigned long long)data->args.offset); | |
287 | } | |
288 | ||
289 | static void | |
290 | nfs_async_read_error(struct list_head *head) | |
291 | { | |
292 | struct nfs_page *req; | |
293 | ||
294 | while (!list_empty(head)) { | |
295 | req = nfs_list_entry(head->next); | |
296 | nfs_list_remove_request(req); | |
297 | SetPageError(req->wb_page); | |
298 | nfs_readpage_release(req); | |
299 | } | |
300 | } | |
301 | ||
302 | /* | |
303 | * Start an async read operation | |
304 | */ | |
305 | static void nfs_execute_read(struct nfs_read_data *data) | |
306 | { | |
307 | struct rpc_clnt *clnt = NFS_CLIENT(data->inode); | |
308 | sigset_t oldset; | |
309 | ||
310 | rpc_clnt_sigmask(clnt, &oldset); | |
1da177e4 | 311 | rpc_execute(&data->task); |
1da177e4 LT |
312 | rpc_clnt_sigunmask(clnt, &oldset); |
313 | } | |
314 | ||
315 | /* | |
316 | * Generate multiple requests to fill a single page. | |
317 | * | |
318 | * We optimize to reduce the number of read operations on the wire. If we | |
319 | * detect that we're reading a page, or an area of a page, that is past the | |
320 | * end of file, we do not generate NFS read operations but just clear the | |
321 | * parts of the page that would have come back zero from the server anyway. | |
322 | * | |
323 | * We rely on the cached value of i_size to make this determination; another | |
324 | * client can fill pages on the server past our cached end-of-file, but we | |
325 | * won't see the new data until our attribute cache is updated. This is more | |
326 | * or less conventional NFS client behavior. | |
327 | */ | |
328 | static int nfs_pagein_multi(struct list_head *head, struct inode *inode) | |
329 | { | |
330 | struct nfs_page *req = nfs_list_entry(head->next); | |
331 | struct page *page = req->wb_page; | |
332 | struct nfs_read_data *data; | |
e9f7bee1 TM |
333 | size_t rsize = NFS_SERVER(inode)->rsize, nbytes; |
334 | unsigned int offset; | |
1da177e4 LT |
335 | int requests = 0; |
336 | LIST_HEAD(list); | |
337 | ||
338 | nfs_list_remove_request(req); | |
339 | ||
340 | nbytes = req->wb_bytes; | |
e9f7bee1 TM |
341 | do { |
342 | size_t len = min(nbytes,rsize); | |
343 | ||
344 | data = nfs_readdata_alloc(len); | |
1da177e4 LT |
345 | if (!data) |
346 | goto out_bad; | |
347 | INIT_LIST_HEAD(&data->pages); | |
348 | list_add(&data->pages, &list); | |
349 | requests++; | |
e9f7bee1 TM |
350 | nbytes -= len; |
351 | } while(nbytes != 0); | |
1da177e4 LT |
352 | atomic_set(&req->wb_complete, requests); |
353 | ||
354 | ClearPageError(page); | |
355 | offset = 0; | |
356 | nbytes = req->wb_bytes; | |
357 | do { | |
358 | data = list_entry(list.next, struct nfs_read_data, pages); | |
359 | list_del_init(&data->pages); | |
360 | ||
361 | data->pagevec[0] = page; | |
1da177e4 LT |
362 | |
363 | if (nbytes > rsize) { | |
ec06c096 TM |
364 | nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, |
365 | rsize, offset); | |
1da177e4 LT |
366 | offset += rsize; |
367 | nbytes -= rsize; | |
368 | } else { | |
ec06c096 TM |
369 | nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, |
370 | nbytes, offset); | |
1da177e4 LT |
371 | nbytes = 0; |
372 | } | |
373 | nfs_execute_read(data); | |
374 | } while (nbytes != 0); | |
375 | ||
376 | return 0; | |
377 | ||
378 | out_bad: | |
379 | while (!list_empty(&list)) { | |
380 | data = list_entry(list.next, struct nfs_read_data, pages); | |
381 | list_del(&data->pages); | |
382 | nfs_readdata_free(data); | |
383 | } | |
384 | SetPageError(page); | |
385 | nfs_readpage_release(req); | |
386 | return -ENOMEM; | |
387 | } | |
388 | ||
389 | static int nfs_pagein_one(struct list_head *head, struct inode *inode) | |
390 | { | |
391 | struct nfs_page *req; | |
392 | struct page **pages; | |
393 | struct nfs_read_data *data; | |
394 | unsigned int count; | |
395 | ||
396 | if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE) | |
397 | return nfs_pagein_multi(head, inode); | |
398 | ||
e9f7bee1 | 399 | data = nfs_readdata_alloc(NFS_SERVER(inode)->rsize); |
1da177e4 LT |
400 | if (!data) |
401 | goto out_bad; | |
402 | ||
403 | INIT_LIST_HEAD(&data->pages); | |
404 | pages = data->pagevec; | |
405 | count = 0; | |
406 | while (!list_empty(head)) { | |
407 | req = nfs_list_entry(head->next); | |
408 | nfs_list_remove_request(req); | |
409 | nfs_list_add_request(req, &data->pages); | |
410 | ClearPageError(req->wb_page); | |
411 | *pages++ = req->wb_page; | |
412 | count += req->wb_bytes; | |
413 | } | |
414 | req = nfs_list_entry(data->pages.next); | |
415 | ||
ec06c096 | 416 | nfs_read_rpcsetup(req, data, &nfs_read_full_ops, count, 0); |
1da177e4 LT |
417 | |
418 | nfs_execute_read(data); | |
419 | return 0; | |
420 | out_bad: | |
421 | nfs_async_read_error(head); | |
422 | return -ENOMEM; | |
423 | } | |
424 | ||
425 | static int | |
426 | nfs_pagein_list(struct list_head *head, int rpages) | |
427 | { | |
428 | LIST_HEAD(one_request); | |
429 | struct nfs_page *req; | |
430 | int error = 0; | |
431 | unsigned int pages = 0; | |
432 | ||
433 | while (!list_empty(head)) { | |
434 | pages += nfs_coalesce_requests(head, &one_request, rpages); | |
435 | req = nfs_list_entry(one_request.next); | |
436 | error = nfs_pagein_one(&one_request, req->wb_context->dentry->d_inode); | |
437 | if (error < 0) | |
438 | break; | |
439 | } | |
440 | if (error >= 0) | |
441 | return pages; | |
442 | ||
443 | nfs_async_read_error(head); | |
444 | return error; | |
445 | } | |
446 | ||
0b671301 TM |
447 | /* |
448 | * This is the callback from RPC telling us whether a reply was | |
449 | * received or some error occurred (timeout or socket shutdown). | |
450 | */ | |
451 | int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data) | |
452 | { | |
453 | int status; | |
454 | ||
455 | dprintk("%s: %4d, (status %d)\n", __FUNCTION__, task->tk_pid, | |
456 | task->tk_status); | |
457 | ||
458 | status = NFS_PROTO(data->inode)->read_done(task, data); | |
459 | if (status != 0) | |
460 | return status; | |
461 | ||
462 | nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, data->res.count); | |
463 | ||
464 | if (task->tk_status == -ESTALE) { | |
465 | set_bit(NFS_INO_STALE, &NFS_FLAGS(data->inode)); | |
466 | nfs_mark_for_revalidate(data->inode); | |
467 | } | |
468 | spin_lock(&data->inode->i_lock); | |
469 | NFS_I(data->inode)->cache_validity |= NFS_INO_INVALID_ATIME; | |
470 | spin_unlock(&data->inode->i_lock); | |
471 | return 0; | |
472 | } | |
473 | ||
474 | static int nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data) | |
475 | { | |
476 | struct nfs_readargs *argp = &data->args; | |
477 | struct nfs_readres *resp = &data->res; | |
478 | ||
479 | if (resp->eof || resp->count == argp->count) | |
480 | return 0; | |
481 | ||
482 | /* This is a short read! */ | |
483 | nfs_inc_stats(data->inode, NFSIOS_SHORTREAD); | |
484 | /* Has the server at least made some progress? */ | |
485 | if (resp->count == 0) | |
486 | return 0; | |
487 | ||
488 | /* Yes, so retry the read at the end of the data */ | |
489 | argp->offset += resp->count; | |
490 | argp->pgbase += resp->count; | |
491 | argp->count -= resp->count; | |
492 | rpc_restart_call(task); | |
493 | return -EAGAIN; | |
494 | } | |
495 | ||
1da177e4 LT |
496 | /* |
497 | * Handle a read reply that fills part of a page. | |
498 | */ | |
ec06c096 | 499 | static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata) |
1da177e4 | 500 | { |
ec06c096 | 501 | struct nfs_read_data *data = calldata; |
1da177e4 LT |
502 | struct nfs_page *req = data->req; |
503 | struct page *page = req->wb_page; | |
504 | ||
ec06c096 TM |
505 | if (nfs_readpage_result(task, data) != 0) |
506 | return; | |
0b671301 TM |
507 | |
508 | if (likely(task->tk_status >= 0)) { | |
509 | nfs_readpage_truncate_uninitialised_page(data); | |
510 | if (nfs_readpage_retry(task, data) != 0) | |
511 | return; | |
512 | } | |
513 | if (unlikely(task->tk_status < 0)) | |
514 | SetPageError(page); | |
1da177e4 LT |
515 | if (atomic_dec_and_test(&req->wb_complete)) { |
516 | if (!PageError(page)) | |
517 | SetPageUptodate(page); | |
518 | nfs_readpage_release(req); | |
519 | } | |
520 | } | |
521 | ||
ec06c096 TM |
522 | static const struct rpc_call_ops nfs_read_partial_ops = { |
523 | .rpc_call_done = nfs_readpage_result_partial, | |
524 | .rpc_release = nfs_readdata_release, | |
525 | }; | |
526 | ||
1de3fc12 TM |
527 | static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data) |
528 | { | |
529 | unsigned int count = data->res.count; | |
530 | unsigned int base = data->args.pgbase; | |
531 | struct page **pages; | |
532 | ||
79558f36 TM |
533 | if (data->res.eof) |
534 | count = data->args.count; | |
1de3fc12 TM |
535 | if (unlikely(count == 0)) |
536 | return; | |
537 | pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; | |
538 | base &= ~PAGE_CACHE_MASK; | |
539 | count += base; | |
540 | for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++) | |
541 | SetPageUptodate(*pages); | |
0b671301 TM |
542 | if (count == 0) |
543 | return; | |
544 | /* Was this a short read? */ | |
545 | if (data->res.eof || data->res.count == data->args.count) | |
1de3fc12 TM |
546 | SetPageUptodate(*pages); |
547 | } | |
548 | ||
1da177e4 LT |
549 | /* |
550 | * This is the callback from RPC telling us whether a reply was | |
551 | * received or some error occurred (timeout or socket shutdown). | |
552 | */ | |
ec06c096 | 553 | static void nfs_readpage_result_full(struct rpc_task *task, void *calldata) |
1da177e4 | 554 | { |
ec06c096 | 555 | struct nfs_read_data *data = calldata; |
1da177e4 | 556 | |
0b671301 TM |
557 | if (nfs_readpage_result(task, data) != 0) |
558 | return; | |
1de3fc12 | 559 | /* |
0b671301 | 560 | * Note: nfs_readpage_retry may change the values of |
1de3fc12 | 561 | * data->args. In the multi-page case, we therefore need |
0b671301 TM |
562 | * to ensure that we call nfs_readpage_set_pages_uptodate() |
563 | * first. | |
1de3fc12 TM |
564 | */ |
565 | if (likely(task->tk_status >= 0)) { | |
566 | nfs_readpage_truncate_uninitialised_page(data); | |
567 | nfs_readpage_set_pages_uptodate(data); | |
0b671301 TM |
568 | if (nfs_readpage_retry(task, data) != 0) |
569 | return; | |
570 | } | |
1da177e4 LT |
571 | while (!list_empty(&data->pages)) { |
572 | struct nfs_page *req = nfs_list_entry(data->pages.next); | |
1da177e4 | 573 | |
1de3fc12 | 574 | nfs_list_remove_request(req); |
1da177e4 LT |
575 | nfs_readpage_release(req); |
576 | } | |
577 | } | |
578 | ||
ec06c096 TM |
579 | static const struct rpc_call_ops nfs_read_full_ops = { |
580 | .rpc_call_done = nfs_readpage_result_full, | |
581 | .rpc_release = nfs_readdata_release, | |
582 | }; | |
583 | ||
1da177e4 LT |
584 | /* |
585 | * Read a page over NFS. | |
586 | * We read the page synchronously in the following case: | |
587 | * - The error flag is set for this page. This happens only when a | |
588 | * previous async read operation failed. | |
589 | */ | |
590 | int nfs_readpage(struct file *file, struct page *page) | |
591 | { | |
592 | struct nfs_open_context *ctx; | |
593 | struct inode *inode = page->mapping->host; | |
594 | int error; | |
595 | ||
596 | dprintk("NFS: nfs_readpage (%p %ld@%lu)\n", | |
597 | page, PAGE_CACHE_SIZE, page->index); | |
91d5b470 CL |
598 | nfs_inc_stats(inode, NFSIOS_VFSREADPAGE); |
599 | nfs_add_stats(inode, NFSIOS_READPAGES, 1); | |
600 | ||
1da177e4 LT |
601 | /* |
602 | * Try to flush any pending writes to the file.. | |
603 | * | |
604 | * NOTE! Because we own the page lock, there cannot | |
605 | * be any new pending writes generated at this point | |
606 | * for this page (other pages can be written to). | |
607 | */ | |
608 | error = nfs_wb_page(inode, page); | |
609 | if (error) | |
610 | goto out_error; | |
611 | ||
5f004cf2 TM |
612 | error = -ESTALE; |
613 | if (NFS_STALE(inode)) | |
614 | goto out_error; | |
615 | ||
1da177e4 | 616 | if (file == NULL) { |
cf1308ff | 617 | error = -EBADF; |
d530838b | 618 | ctx = nfs_find_open_context(inode, NULL, FMODE_READ); |
1da177e4 | 619 | if (ctx == NULL) |
cf1308ff | 620 | goto out_error; |
1da177e4 LT |
621 | } else |
622 | ctx = get_nfs_open_context((struct nfs_open_context *) | |
623 | file->private_data); | |
624 | if (!IS_SYNC(inode)) { | |
625 | error = nfs_readpage_async(ctx, inode, page); | |
626 | goto out; | |
627 | } | |
628 | ||
629 | error = nfs_readpage_sync(ctx, inode, page); | |
630 | if (error < 0 && IS_SWAPFILE(inode)) | |
631 | printk("Aiee.. nfs swap-in of page failed!\n"); | |
632 | out: | |
633 | put_nfs_open_context(ctx); | |
634 | return error; | |
635 | ||
636 | out_error: | |
637 | unlock_page(page); | |
638 | return error; | |
639 | } | |
640 | ||
641 | struct nfs_readdesc { | |
642 | struct list_head *head; | |
643 | struct nfs_open_context *ctx; | |
644 | }; | |
645 | ||
646 | static int | |
647 | readpage_async_filler(void *data, struct page *page) | |
648 | { | |
649 | struct nfs_readdesc *desc = (struct nfs_readdesc *)data; | |
650 | struct inode *inode = page->mapping->host; | |
651 | struct nfs_page *new; | |
652 | unsigned int len; | |
653 | ||
654 | nfs_wb_page(inode, page); | |
49a70f27 | 655 | len = nfs_page_length(page); |
1da177e4 LT |
656 | if (len == 0) |
657 | return nfs_return_empty_page(page); | |
658 | new = nfs_create_request(desc->ctx, inode, page, 0, len); | |
659 | if (IS_ERR(new)) { | |
660 | SetPageError(page); | |
661 | unlock_page(page); | |
662 | return PTR_ERR(new); | |
663 | } | |
664 | if (len < PAGE_CACHE_SIZE) | |
665 | memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len); | |
1da177e4 LT |
666 | nfs_list_add_request(new, desc->head); |
667 | return 0; | |
668 | } | |
669 | ||
670 | int nfs_readpages(struct file *filp, struct address_space *mapping, | |
671 | struct list_head *pages, unsigned nr_pages) | |
672 | { | |
673 | LIST_HEAD(head); | |
674 | struct nfs_readdesc desc = { | |
675 | .head = &head, | |
676 | }; | |
677 | struct inode *inode = mapping->host; | |
678 | struct nfs_server *server = NFS_SERVER(inode); | |
5f004cf2 | 679 | int ret = -ESTALE; |
1da177e4 LT |
680 | |
681 | dprintk("NFS: nfs_readpages (%s/%Ld %d)\n", | |
682 | inode->i_sb->s_id, | |
683 | (long long)NFS_FILEID(inode), | |
684 | nr_pages); | |
91d5b470 | 685 | nfs_inc_stats(inode, NFSIOS_VFSREADPAGES); |
1da177e4 | 686 | |
5f004cf2 TM |
687 | if (NFS_STALE(inode)) |
688 | goto out; | |
689 | ||
1da177e4 | 690 | if (filp == NULL) { |
d530838b | 691 | desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ); |
1da177e4 LT |
692 | if (desc.ctx == NULL) |
693 | return -EBADF; | |
694 | } else | |
695 | desc.ctx = get_nfs_open_context((struct nfs_open_context *) | |
696 | filp->private_data); | |
697 | ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc); | |
698 | if (!list_empty(&head)) { | |
699 | int err = nfs_pagein_list(&head, server->rpages); | |
700 | if (!ret) | |
91d5b470 | 701 | nfs_add_stats(inode, NFSIOS_READPAGES, err); |
1da177e4 LT |
702 | ret = err; |
703 | } | |
704 | put_nfs_open_context(desc.ctx); | |
5f004cf2 | 705 | out: |
1da177e4 LT |
706 | return ret; |
707 | } | |
708 | ||
f7b422b1 | 709 | int __init nfs_init_readpagecache(void) |
1da177e4 LT |
710 | { |
711 | nfs_rdata_cachep = kmem_cache_create("nfs_read_data", | |
712 | sizeof(struct nfs_read_data), | |
713 | 0, SLAB_HWCACHE_ALIGN, | |
714 | NULL, NULL); | |
715 | if (nfs_rdata_cachep == NULL) | |
716 | return -ENOMEM; | |
717 | ||
93d2341c MD |
718 | nfs_rdata_mempool = mempool_create_slab_pool(MIN_POOL_READ, |
719 | nfs_rdata_cachep); | |
1da177e4 LT |
720 | if (nfs_rdata_mempool == NULL) |
721 | return -ENOMEM; | |
722 | ||
723 | return 0; | |
724 | } | |
725 | ||
266bee88 | 726 | void nfs_destroy_readpagecache(void) |
1da177e4 LT |
727 | { |
728 | mempool_destroy(nfs_rdata_mempool); | |
1a1d92c1 | 729 | kmem_cache_destroy(nfs_rdata_cachep); |
1da177e4 | 730 | } |