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Commit | Line | Data |
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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 | ||
91d5b470 CL |
33 | #include "iostat.h" |
34 | ||
1da177e4 LT |
35 | #define NFSDBG_FACILITY NFSDBG_PAGECACHE |
36 | ||
37 | static int nfs_pagein_one(struct list_head *, struct inode *); | |
ec06c096 TM |
38 | static const struct rpc_call_ops nfs_read_partial_ops; |
39 | static const struct rpc_call_ops nfs_read_full_ops; | |
1da177e4 LT |
40 | |
41 | static kmem_cache_t *nfs_rdata_cachep; | |
3feb2d49 | 42 | static mempool_t *nfs_rdata_mempool; |
1da177e4 LT |
43 | |
44 | #define MIN_POOL_READ (32) | |
45 | ||
3feb2d49 TM |
46 | struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount) |
47 | { | |
48 | struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, SLAB_NOFS); | |
49 | ||
50 | if (p) { | |
51 | memset(p, 0, sizeof(*p)); | |
52 | INIT_LIST_HEAD(&p->pages); | |
0d0b5cb3 CL |
53 | if (pagecount <= ARRAY_SIZE(p->page_array)) |
54 | p->pagevec = p->page_array; | |
3feb2d49 | 55 | else { |
0d0b5cb3 CL |
56 | p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS); |
57 | if (!p->pagevec) { | |
3feb2d49 TM |
58 | mempool_free(p, nfs_rdata_mempool); |
59 | p = NULL; | |
60 | } | |
61 | } | |
62 | } | |
63 | return p; | |
64 | } | |
65 | ||
e4e20512 | 66 | static void nfs_readdata_free(struct nfs_read_data *p) |
3feb2d49 TM |
67 | { |
68 | if (p && (p->pagevec != &p->page_array[0])) | |
69 | kfree(p->pagevec); | |
70 | mempool_free(p, nfs_rdata_mempool); | |
71 | } | |
72 | ||
963d8fe5 | 73 | void nfs_readdata_release(void *data) |
1da177e4 | 74 | { |
1da177e4 LT |
75 | nfs_readdata_free(data); |
76 | } | |
77 | ||
78 | static | |
79 | unsigned int nfs_page_length(struct inode *inode, struct page *page) | |
80 | { | |
81 | loff_t i_size = i_size_read(inode); | |
82 | unsigned long idx; | |
83 | ||
84 | if (i_size <= 0) | |
85 | return 0; | |
86 | idx = (i_size - 1) >> PAGE_CACHE_SHIFT; | |
87 | if (page->index > idx) | |
88 | return 0; | |
89 | if (page->index != idx) | |
90 | return PAGE_CACHE_SIZE; | |
91 | return 1 + ((i_size - 1) & (PAGE_CACHE_SIZE - 1)); | |
92 | } | |
93 | ||
94 | static | |
95 | int nfs_return_empty_page(struct page *page) | |
96 | { | |
97 | memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE); | |
98 | SetPageUptodate(page); | |
99 | unlock_page(page); | |
100 | return 0; | |
101 | } | |
102 | ||
1de3fc12 TM |
103 | static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data) |
104 | { | |
105 | unsigned int remainder = data->args.count - data->res.count; | |
106 | unsigned int base = data->args.pgbase + data->res.count; | |
107 | unsigned int pglen; | |
108 | struct page **pages; | |
109 | ||
110 | if (data->res.eof == 0 || remainder == 0) | |
111 | return; | |
112 | /* | |
113 | * Note: "remainder" can never be negative, since we check for | |
114 | * this in the XDR code. | |
115 | */ | |
116 | pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; | |
117 | base &= ~PAGE_CACHE_MASK; | |
118 | pglen = PAGE_CACHE_SIZE - base; | |
119 | if (pglen < remainder) | |
120 | memclear_highpage_flush(*pages, base, pglen); | |
121 | else | |
122 | memclear_highpage_flush(*pages, base, remainder); | |
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; | |
133 | int result; | |
134 | struct nfs_read_data *rdata; | |
135 | ||
40859d7e | 136 | rdata = nfs_readdata_alloc(1); |
1da177e4 LT |
137 | if (!rdata) |
138 | return -ENOMEM; | |
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", | |
165 | NFS_SERVER(inode)->hostname, | |
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 | |
1de3fc12 TM |
198 | nfs_readpage_truncate_uninitialised_page(rdata); |
199 | if (rdata->res.eof || rdata->res.count == rdata->args.count) | |
200 | SetPageUptodate(page); | |
1da177e4 LT |
201 | result = 0; |
202 | ||
203 | io_error: | |
204 | unlock_page(page); | |
205 | nfs_readdata_free(rdata); | |
206 | return result; | |
207 | } | |
208 | ||
209 | static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, | |
210 | struct page *page) | |
211 | { | |
212 | LIST_HEAD(one_request); | |
213 | struct nfs_page *new; | |
214 | unsigned int len; | |
215 | ||
216 | len = nfs_page_length(inode, page); | |
217 | if (len == 0) | |
218 | return nfs_return_empty_page(page); | |
219 | new = nfs_create_request(ctx, inode, page, 0, len); | |
220 | if (IS_ERR(new)) { | |
221 | unlock_page(page); | |
222 | return PTR_ERR(new); | |
223 | } | |
224 | if (len < PAGE_CACHE_SIZE) | |
225 | memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len); | |
226 | ||
1da177e4 LT |
227 | nfs_list_add_request(new, &one_request); |
228 | nfs_pagein_one(&one_request, inode); | |
229 | return 0; | |
230 | } | |
231 | ||
232 | static void nfs_readpage_release(struct nfs_page *req) | |
233 | { | |
234 | unlock_page(req->wb_page); | |
235 | ||
1da177e4 LT |
236 | dprintk("NFS: read done (%s/%Ld %d@%Ld)\n", |
237 | req->wb_context->dentry->d_inode->i_sb->s_id, | |
238 | (long long)NFS_FILEID(req->wb_context->dentry->d_inode), | |
239 | req->wb_bytes, | |
240 | (long long)req_offset(req)); | |
10d2c46f NW |
241 | nfs_clear_request(req); |
242 | nfs_release_request(req); | |
1da177e4 LT |
243 | } |
244 | ||
245 | /* | |
246 | * Set up the NFS read request struct | |
247 | */ | |
248 | static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data, | |
ec06c096 | 249 | const struct rpc_call_ops *call_ops, |
1da177e4 LT |
250 | unsigned int count, unsigned int offset) |
251 | { | |
252 | struct inode *inode; | |
ec06c096 | 253 | int flags; |
1da177e4 LT |
254 | |
255 | data->req = req; | |
256 | data->inode = inode = req->wb_context->dentry->d_inode; | |
257 | data->cred = req->wb_context->cred; | |
258 | ||
259 | data->args.fh = NFS_FH(inode); | |
260 | data->args.offset = req_offset(req) + offset; | |
261 | data->args.pgbase = req->wb_pgbase + offset; | |
262 | data->args.pages = data->pagevec; | |
263 | data->args.count = count; | |
264 | data->args.context = req->wb_context; | |
265 | ||
266 | data->res.fattr = &data->fattr; | |
267 | data->res.count = count; | |
268 | data->res.eof = 0; | |
0e574af1 | 269 | nfs_fattr_init(&data->fattr); |
1da177e4 | 270 | |
ec06c096 TM |
271 | /* Set up the initial task struct. */ |
272 | flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0); | |
273 | rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data); | |
1da177e4 LT |
274 | NFS_PROTO(inode)->read_setup(data); |
275 | ||
276 | data->task.tk_cookie = (unsigned long)inode; | |
1da177e4 LT |
277 | |
278 | dprintk("NFS: %4d initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n", | |
279 | data->task.tk_pid, | |
280 | inode->i_sb->s_id, | |
281 | (long long)NFS_FILEID(inode), | |
282 | count, | |
283 | (unsigned long long)data->args.offset); | |
284 | } | |
285 | ||
286 | static void | |
287 | nfs_async_read_error(struct list_head *head) | |
288 | { | |
289 | struct nfs_page *req; | |
290 | ||
291 | while (!list_empty(head)) { | |
292 | req = nfs_list_entry(head->next); | |
293 | nfs_list_remove_request(req); | |
294 | SetPageError(req->wb_page); | |
295 | nfs_readpage_release(req); | |
296 | } | |
297 | } | |
298 | ||
299 | /* | |
300 | * Start an async read operation | |
301 | */ | |
302 | static void nfs_execute_read(struct nfs_read_data *data) | |
303 | { | |
304 | struct rpc_clnt *clnt = NFS_CLIENT(data->inode); | |
305 | sigset_t oldset; | |
306 | ||
307 | rpc_clnt_sigmask(clnt, &oldset); | |
308 | lock_kernel(); | |
309 | rpc_execute(&data->task); | |
310 | unlock_kernel(); | |
311 | rpc_clnt_sigunmask(clnt, &oldset); | |
312 | } | |
313 | ||
314 | /* | |
315 | * Generate multiple requests to fill a single page. | |
316 | * | |
317 | * We optimize to reduce the number of read operations on the wire. If we | |
318 | * detect that we're reading a page, or an area of a page, that is past the | |
319 | * end of file, we do not generate NFS read operations but just clear the | |
320 | * parts of the page that would have come back zero from the server anyway. | |
321 | * | |
322 | * We rely on the cached value of i_size to make this determination; another | |
323 | * client can fill pages on the server past our cached end-of-file, but we | |
324 | * won't see the new data until our attribute cache is updated. This is more | |
325 | * or less conventional NFS client behavior. | |
326 | */ | |
327 | static int nfs_pagein_multi(struct list_head *head, struct inode *inode) | |
328 | { | |
329 | struct nfs_page *req = nfs_list_entry(head->next); | |
330 | struct page *page = req->wb_page; | |
331 | struct nfs_read_data *data; | |
332 | unsigned int rsize = NFS_SERVER(inode)->rsize; | |
333 | unsigned int nbytes, offset; | |
334 | int requests = 0; | |
335 | LIST_HEAD(list); | |
336 | ||
337 | nfs_list_remove_request(req); | |
338 | ||
339 | nbytes = req->wb_bytes; | |
340 | for(;;) { | |
40859d7e | 341 | data = nfs_readdata_alloc(1); |
1da177e4 LT |
342 | if (!data) |
343 | goto out_bad; | |
344 | INIT_LIST_HEAD(&data->pages); | |
345 | list_add(&data->pages, &list); | |
346 | requests++; | |
347 | if (nbytes <= rsize) | |
348 | break; | |
349 | nbytes -= rsize; | |
350 | } | |
351 | atomic_set(&req->wb_complete, requests); | |
352 | ||
353 | ClearPageError(page); | |
354 | offset = 0; | |
355 | nbytes = req->wb_bytes; | |
356 | do { | |
357 | data = list_entry(list.next, struct nfs_read_data, pages); | |
358 | list_del_init(&data->pages); | |
359 | ||
360 | data->pagevec[0] = page; | |
1da177e4 LT |
361 | |
362 | if (nbytes > rsize) { | |
ec06c096 TM |
363 | nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, |
364 | rsize, offset); | |
1da177e4 LT |
365 | offset += rsize; |
366 | nbytes -= rsize; | |
367 | } else { | |
ec06c096 TM |
368 | nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, |
369 | nbytes, offset); | |
1da177e4 LT |
370 | nbytes = 0; |
371 | } | |
372 | nfs_execute_read(data); | |
373 | } while (nbytes != 0); | |
374 | ||
375 | return 0; | |
376 | ||
377 | out_bad: | |
378 | while (!list_empty(&list)) { | |
379 | data = list_entry(list.next, struct nfs_read_data, pages); | |
380 | list_del(&data->pages); | |
381 | nfs_readdata_free(data); | |
382 | } | |
383 | SetPageError(page); | |
384 | nfs_readpage_release(req); | |
385 | return -ENOMEM; | |
386 | } | |
387 | ||
388 | static int nfs_pagein_one(struct list_head *head, struct inode *inode) | |
389 | { | |
390 | struct nfs_page *req; | |
391 | struct page **pages; | |
392 | struct nfs_read_data *data; | |
393 | unsigned int count; | |
394 | ||
395 | if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE) | |
396 | return nfs_pagein_multi(head, inode); | |
397 | ||
40859d7e | 398 | data = nfs_readdata_alloc(NFS_SERVER(inode)->rpages); |
1da177e4 LT |
399 | if (!data) |
400 | goto out_bad; | |
401 | ||
402 | INIT_LIST_HEAD(&data->pages); | |
403 | pages = data->pagevec; | |
404 | count = 0; | |
405 | while (!list_empty(head)) { | |
406 | req = nfs_list_entry(head->next); | |
407 | nfs_list_remove_request(req); | |
408 | nfs_list_add_request(req, &data->pages); | |
409 | ClearPageError(req->wb_page); | |
410 | *pages++ = req->wb_page; | |
411 | count += req->wb_bytes; | |
412 | } | |
413 | req = nfs_list_entry(data->pages.next); | |
414 | ||
ec06c096 | 415 | nfs_read_rpcsetup(req, data, &nfs_read_full_ops, count, 0); |
1da177e4 LT |
416 | |
417 | nfs_execute_read(data); | |
418 | return 0; | |
419 | out_bad: | |
420 | nfs_async_read_error(head); | |
421 | return -ENOMEM; | |
422 | } | |
423 | ||
424 | static int | |
425 | nfs_pagein_list(struct list_head *head, int rpages) | |
426 | { | |
427 | LIST_HEAD(one_request); | |
428 | struct nfs_page *req; | |
429 | int error = 0; | |
430 | unsigned int pages = 0; | |
431 | ||
432 | while (!list_empty(head)) { | |
433 | pages += nfs_coalesce_requests(head, &one_request, rpages); | |
434 | req = nfs_list_entry(one_request.next); | |
435 | error = nfs_pagein_one(&one_request, req->wb_context->dentry->d_inode); | |
436 | if (error < 0) | |
437 | break; | |
438 | } | |
439 | if (error >= 0) | |
440 | return pages; | |
441 | ||
442 | nfs_async_read_error(head); | |
443 | return error; | |
444 | } | |
445 | ||
446 | /* | |
447 | * Handle a read reply that fills part of a page. | |
448 | */ | |
ec06c096 | 449 | static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata) |
1da177e4 | 450 | { |
ec06c096 | 451 | struct nfs_read_data *data = calldata; |
1da177e4 LT |
452 | struct nfs_page *req = data->req; |
453 | struct page *page = req->wb_page; | |
454 | ||
1de3fc12 TM |
455 | if (likely(task->tk_status >= 0)) |
456 | nfs_readpage_truncate_uninitialised_page(data); | |
457 | else | |
458 | SetPageError(page); | |
ec06c096 TM |
459 | if (nfs_readpage_result(task, data) != 0) |
460 | return; | |
1da177e4 LT |
461 | if (atomic_dec_and_test(&req->wb_complete)) { |
462 | if (!PageError(page)) | |
463 | SetPageUptodate(page); | |
464 | nfs_readpage_release(req); | |
465 | } | |
466 | } | |
467 | ||
ec06c096 TM |
468 | static const struct rpc_call_ops nfs_read_partial_ops = { |
469 | .rpc_call_done = nfs_readpage_result_partial, | |
470 | .rpc_release = nfs_readdata_release, | |
471 | }; | |
472 | ||
1de3fc12 TM |
473 | static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data) |
474 | { | |
475 | unsigned int count = data->res.count; | |
476 | unsigned int base = data->args.pgbase; | |
477 | struct page **pages; | |
478 | ||
479 | if (unlikely(count == 0)) | |
480 | return; | |
481 | pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; | |
482 | base &= ~PAGE_CACHE_MASK; | |
483 | count += base; | |
484 | for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++) | |
485 | SetPageUptodate(*pages); | |
486 | /* | |
487 | * Was this an eof or a short read? If the latter, don't mark the page | |
488 | * as uptodate yet. | |
489 | */ | |
490 | if (count > 0 && (data->res.eof || data->args.count == data->res.count)) | |
491 | SetPageUptodate(*pages); | |
492 | } | |
493 | ||
494 | static void nfs_readpage_set_pages_error(struct nfs_read_data *data) | |
495 | { | |
496 | unsigned int count = data->args.count; | |
497 | unsigned int base = data->args.pgbase; | |
498 | struct page **pages; | |
499 | ||
500 | pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; | |
501 | base &= ~PAGE_CACHE_MASK; | |
502 | count += base; | |
503 | for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++) | |
504 | SetPageError(*pages); | |
505 | } | |
506 | ||
1da177e4 LT |
507 | /* |
508 | * This is the callback from RPC telling us whether a reply was | |
509 | * received or some error occurred (timeout or socket shutdown). | |
510 | */ | |
ec06c096 | 511 | static void nfs_readpage_result_full(struct rpc_task *task, void *calldata) |
1da177e4 | 512 | { |
ec06c096 | 513 | struct nfs_read_data *data = calldata; |
1da177e4 | 514 | |
1de3fc12 TM |
515 | /* |
516 | * Note: nfs_readpage_result may change the values of | |
517 | * data->args. In the multi-page case, we therefore need | |
518 | * to ensure that we call the next nfs_readpage_set_page_uptodate() | |
519 | * first in the multi-page case. | |
520 | */ | |
521 | if (likely(task->tk_status >= 0)) { | |
522 | nfs_readpage_truncate_uninitialised_page(data); | |
523 | nfs_readpage_set_pages_uptodate(data); | |
524 | } else | |
525 | nfs_readpage_set_pages_error(data); | |
ec06c096 TM |
526 | if (nfs_readpage_result(task, data) != 0) |
527 | return; | |
1da177e4 LT |
528 | while (!list_empty(&data->pages)) { |
529 | struct nfs_page *req = nfs_list_entry(data->pages.next); | |
1da177e4 | 530 | |
1de3fc12 | 531 | nfs_list_remove_request(req); |
1da177e4 LT |
532 | nfs_readpage_release(req); |
533 | } | |
534 | } | |
535 | ||
ec06c096 TM |
536 | static const struct rpc_call_ops nfs_read_full_ops = { |
537 | .rpc_call_done = nfs_readpage_result_full, | |
538 | .rpc_release = nfs_readdata_release, | |
539 | }; | |
540 | ||
1da177e4 LT |
541 | /* |
542 | * This is the callback from RPC telling us whether a reply was | |
543 | * received or some error occurred (timeout or socket shutdown). | |
544 | */ | |
ec06c096 | 545 | int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data) |
1da177e4 | 546 | { |
1da177e4 LT |
547 | struct nfs_readargs *argp = &data->args; |
548 | struct nfs_readres *resp = &data->res; | |
ec06c096 | 549 | int status; |
1da177e4 LT |
550 | |
551 | dprintk("NFS: %4d nfs_readpage_result, (status %d)\n", | |
ec06c096 TM |
552 | task->tk_pid, task->tk_status); |
553 | ||
554 | status = NFS_PROTO(data->inode)->read_done(task, data); | |
555 | if (status != 0) | |
556 | return status; | |
1da177e4 | 557 | |
91d5b470 CL |
558 | nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, resp->count); |
559 | ||
1da177e4 LT |
560 | /* Is this a short read? */ |
561 | if (task->tk_status >= 0 && resp->count < argp->count && !resp->eof) { | |
91d5b470 | 562 | nfs_inc_stats(data->inode, NFSIOS_SHORTREAD); |
1da177e4 LT |
563 | /* Has the server at least made some progress? */ |
564 | if (resp->count != 0) { | |
565 | /* Yes, so retry the read at the end of the data */ | |
566 | argp->offset += resp->count; | |
567 | argp->pgbase += resp->count; | |
568 | argp->count -= resp->count; | |
569 | rpc_restart_call(task); | |
ec06c096 | 570 | return -EAGAIN; |
1da177e4 LT |
571 | } |
572 | task->tk_status = -EIO; | |
573 | } | |
dc59250c | 574 | spin_lock(&data->inode->i_lock); |
55296809 | 575 | NFS_I(data->inode)->cache_validity |= NFS_INO_INVALID_ATIME; |
dc59250c | 576 | spin_unlock(&data->inode->i_lock); |
ec06c096 | 577 | return 0; |
1da177e4 LT |
578 | } |
579 | ||
580 | /* | |
581 | * Read a page over NFS. | |
582 | * We read the page synchronously in the following case: | |
583 | * - The error flag is set for this page. This happens only when a | |
584 | * previous async read operation failed. | |
585 | */ | |
586 | int nfs_readpage(struct file *file, struct page *page) | |
587 | { | |
588 | struct nfs_open_context *ctx; | |
589 | struct inode *inode = page->mapping->host; | |
590 | int error; | |
591 | ||
592 | dprintk("NFS: nfs_readpage (%p %ld@%lu)\n", | |
593 | page, PAGE_CACHE_SIZE, page->index); | |
91d5b470 CL |
594 | nfs_inc_stats(inode, NFSIOS_VFSREADPAGE); |
595 | nfs_add_stats(inode, NFSIOS_READPAGES, 1); | |
596 | ||
1da177e4 LT |
597 | /* |
598 | * Try to flush any pending writes to the file.. | |
599 | * | |
600 | * NOTE! Because we own the page lock, there cannot | |
601 | * be any new pending writes generated at this point | |
602 | * for this page (other pages can be written to). | |
603 | */ | |
604 | error = nfs_wb_page(inode, page); | |
605 | if (error) | |
606 | goto out_error; | |
607 | ||
608 | if (file == NULL) { | |
d530838b | 609 | ctx = nfs_find_open_context(inode, NULL, FMODE_READ); |
1da177e4 LT |
610 | if (ctx == NULL) |
611 | return -EBADF; | |
612 | } else | |
613 | ctx = get_nfs_open_context((struct nfs_open_context *) | |
614 | file->private_data); | |
615 | if (!IS_SYNC(inode)) { | |
616 | error = nfs_readpage_async(ctx, inode, page); | |
617 | goto out; | |
618 | } | |
619 | ||
620 | error = nfs_readpage_sync(ctx, inode, page); | |
621 | if (error < 0 && IS_SWAPFILE(inode)) | |
622 | printk("Aiee.. nfs swap-in of page failed!\n"); | |
623 | out: | |
624 | put_nfs_open_context(ctx); | |
625 | return error; | |
626 | ||
627 | out_error: | |
628 | unlock_page(page); | |
629 | return error; | |
630 | } | |
631 | ||
632 | struct nfs_readdesc { | |
633 | struct list_head *head; | |
634 | struct nfs_open_context *ctx; | |
635 | }; | |
636 | ||
637 | static int | |
638 | readpage_async_filler(void *data, struct page *page) | |
639 | { | |
640 | struct nfs_readdesc *desc = (struct nfs_readdesc *)data; | |
641 | struct inode *inode = page->mapping->host; | |
642 | struct nfs_page *new; | |
643 | unsigned int len; | |
644 | ||
645 | nfs_wb_page(inode, page); | |
646 | len = nfs_page_length(inode, page); | |
647 | if (len == 0) | |
648 | return nfs_return_empty_page(page); | |
649 | new = nfs_create_request(desc->ctx, inode, page, 0, len); | |
650 | if (IS_ERR(new)) { | |
651 | SetPageError(page); | |
652 | unlock_page(page); | |
653 | return PTR_ERR(new); | |
654 | } | |
655 | if (len < PAGE_CACHE_SIZE) | |
656 | memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len); | |
1da177e4 LT |
657 | nfs_list_add_request(new, desc->head); |
658 | return 0; | |
659 | } | |
660 | ||
661 | int nfs_readpages(struct file *filp, struct address_space *mapping, | |
662 | struct list_head *pages, unsigned nr_pages) | |
663 | { | |
664 | LIST_HEAD(head); | |
665 | struct nfs_readdesc desc = { | |
666 | .head = &head, | |
667 | }; | |
668 | struct inode *inode = mapping->host; | |
669 | struct nfs_server *server = NFS_SERVER(inode); | |
670 | int ret; | |
671 | ||
672 | dprintk("NFS: nfs_readpages (%s/%Ld %d)\n", | |
673 | inode->i_sb->s_id, | |
674 | (long long)NFS_FILEID(inode), | |
675 | nr_pages); | |
91d5b470 | 676 | nfs_inc_stats(inode, NFSIOS_VFSREADPAGES); |
1da177e4 LT |
677 | |
678 | if (filp == NULL) { | |
d530838b | 679 | desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ); |
1da177e4 LT |
680 | if (desc.ctx == NULL) |
681 | return -EBADF; | |
682 | } else | |
683 | desc.ctx = get_nfs_open_context((struct nfs_open_context *) | |
684 | filp->private_data); | |
685 | ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc); | |
686 | if (!list_empty(&head)) { | |
687 | int err = nfs_pagein_list(&head, server->rpages); | |
688 | if (!ret) | |
91d5b470 | 689 | nfs_add_stats(inode, NFSIOS_READPAGES, err); |
1da177e4 LT |
690 | ret = err; |
691 | } | |
692 | put_nfs_open_context(desc.ctx); | |
693 | return ret; | |
694 | } | |
695 | ||
f7b422b1 | 696 | int __init nfs_init_readpagecache(void) |
1da177e4 LT |
697 | { |
698 | nfs_rdata_cachep = kmem_cache_create("nfs_read_data", | |
699 | sizeof(struct nfs_read_data), | |
700 | 0, SLAB_HWCACHE_ALIGN, | |
701 | NULL, NULL); | |
702 | if (nfs_rdata_cachep == NULL) | |
703 | return -ENOMEM; | |
704 | ||
93d2341c MD |
705 | nfs_rdata_mempool = mempool_create_slab_pool(MIN_POOL_READ, |
706 | nfs_rdata_cachep); | |
1da177e4 LT |
707 | if (nfs_rdata_mempool == NULL) |
708 | return -ENOMEM; | |
709 | ||
710 | return 0; | |
711 | } | |
712 | ||
266bee88 | 713 | void nfs_destroy_readpagecache(void) |
1da177e4 LT |
714 | { |
715 | mempool_destroy(nfs_rdata_mempool); | |
716 | if (kmem_cache_destroy(nfs_rdata_cachep)) | |
717 | printk(KERN_INFO "nfs_read_data: not all structures were freed\n"); | |
718 | } |