blob: 2da255f0247fbb3911d269e925e264a45ba30104 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
18#include <linux/config.h>
19#include <linux/time.h>
20#include <linux/kernel.h>
21#include <linux/errno.h>
22#include <linux/fcntl.h>
23#include <linux/stat.h>
24#include <linux/mm.h>
25#include <linux/slab.h>
26#include <linux/pagemap.h>
27#include <linux/sunrpc/clnt.h>
28#include <linux/nfs_fs.h>
29#include <linux/nfs_page.h>
30#include <linux/smp_lock.h>
31
32#include <asm/system.h>
33
Chuck Lever91d5b472006-03-20 13:44:14 -050034#include "iostat.h"
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#define NFSDBG_FACILITY NFSDBG_PAGECACHE
37
38static int nfs_pagein_one(struct list_head *, struct inode *);
Trond Myklebustec06c092006-03-20 13:44:27 -050039static const struct rpc_call_ops nfs_read_partial_ops;
40static const struct rpc_call_ops nfs_read_full_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42static kmem_cache_t *nfs_rdata_cachep;
43mempool_t *nfs_rdata_mempool;
44
45#define MIN_POOL_READ (32)
46
Trond Myklebust963d8fe2006-01-03 09:55:04 +010047void nfs_readdata_release(void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070048{
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 nfs_readdata_free(data);
50}
51
52static
53unsigned int nfs_page_length(struct inode *inode, struct page *page)
54{
55 loff_t i_size = i_size_read(inode);
56 unsigned long idx;
57
58 if (i_size <= 0)
59 return 0;
60 idx = (i_size - 1) >> PAGE_CACHE_SHIFT;
61 if (page->index > idx)
62 return 0;
63 if (page->index != idx)
64 return PAGE_CACHE_SIZE;
65 return 1 + ((i_size - 1) & (PAGE_CACHE_SIZE - 1));
66}
67
68static
69int nfs_return_empty_page(struct page *page)
70{
71 memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE);
72 SetPageUptodate(page);
73 unlock_page(page);
74 return 0;
75}
76
77/*
78 * Read a page synchronously.
79 */
80static int nfs_readpage_sync(struct nfs_open_context *ctx, struct inode *inode,
81 struct page *page)
82{
83 unsigned int rsize = NFS_SERVER(inode)->rsize;
84 unsigned int count = PAGE_CACHE_SIZE;
85 int result;
86 struct nfs_read_data *rdata;
87
Chuck Lever40859d72005-11-30 18:09:02 -050088 rdata = nfs_readdata_alloc(1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 if (!rdata)
90 return -ENOMEM;
91
92 memset(rdata, 0, sizeof(*rdata));
93 rdata->flags = (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
94 rdata->cred = ctx->cred;
95 rdata->inode = inode;
96 INIT_LIST_HEAD(&rdata->pages);
97 rdata->args.fh = NFS_FH(inode);
98 rdata->args.context = ctx;
99 rdata->args.pages = &page;
100 rdata->args.pgbase = 0UL;
101 rdata->args.count = rsize;
102 rdata->res.fattr = &rdata->fattr;
103
104 dprintk("NFS: nfs_readpage_sync(%p)\n", page);
105
106 /*
107 * This works now because the socket layer never tries to DMA
108 * into this buffer directly.
109 */
110 do {
111 if (count < rsize)
112 rdata->args.count = count;
113 rdata->res.count = rdata->args.count;
114 rdata->args.offset = page_offset(page) + rdata->args.pgbase;
115
116 dprintk("NFS: nfs_proc_read(%s, (%s/%Ld), %Lu, %u)\n",
117 NFS_SERVER(inode)->hostname,
118 inode->i_sb->s_id,
119 (long long)NFS_FILEID(inode),
120 (unsigned long long)rdata->args.pgbase,
121 rdata->args.count);
122
123 lock_kernel();
124 result = NFS_PROTO(inode)->read(rdata);
125 unlock_kernel();
126
127 /*
128 * Even if we had a partial success we can't mark the page
129 * cache valid.
130 */
131 if (result < 0) {
132 if (result == -EISDIR)
133 result = -EINVAL;
134 goto io_error;
135 }
136 count -= result;
137 rdata->args.pgbase += result;
Chuck Lever91d5b472006-03-20 13:44:14 -0500138 nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, result);
139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 /* Note: result == 0 should only happen if we're caching
141 * a write that extends the file and punches a hole.
142 */
143 if (rdata->res.eof != 0 || result == 0)
144 break;
145 } while (count);
Chuck Leverdc592502005-08-18 11:24:12 -0700146 spin_lock(&inode->i_lock);
Chuck Lever55296802005-08-18 11:24:09 -0700147 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
Chuck Leverdc592502005-08-18 11:24:12 -0700148 spin_unlock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149
150 if (count)
151 memclear_highpage_flush(page, rdata->args.pgbase, count);
152 SetPageUptodate(page);
153 if (PageError(page))
154 ClearPageError(page);
155 result = 0;
156
157io_error:
158 unlock_page(page);
159 nfs_readdata_free(rdata);
160 return result;
161}
162
163static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
164 struct page *page)
165{
166 LIST_HEAD(one_request);
167 struct nfs_page *new;
168 unsigned int len;
169
170 len = nfs_page_length(inode, page);
171 if (len == 0)
172 return nfs_return_empty_page(page);
173 new = nfs_create_request(ctx, inode, page, 0, len);
174 if (IS_ERR(new)) {
175 unlock_page(page);
176 return PTR_ERR(new);
177 }
178 if (len < PAGE_CACHE_SIZE)
179 memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
180
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 nfs_list_add_request(new, &one_request);
182 nfs_pagein_one(&one_request, inode);
183 return 0;
184}
185
186static void nfs_readpage_release(struct nfs_page *req)
187{
188 unlock_page(req->wb_page);
189
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
191 req->wb_context->dentry->d_inode->i_sb->s_id,
192 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
193 req->wb_bytes,
194 (long long)req_offset(req));
Nick Wilson10d2c462005-09-22 21:44:28 -0700195 nfs_clear_request(req);
196 nfs_release_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197}
198
199/*
200 * Set up the NFS read request struct
201 */
202static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
Trond Myklebustec06c092006-03-20 13:44:27 -0500203 const struct rpc_call_ops *call_ops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 unsigned int count, unsigned int offset)
205{
206 struct inode *inode;
Trond Myklebustec06c092006-03-20 13:44:27 -0500207 int flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
209 data->req = req;
210 data->inode = inode = req->wb_context->dentry->d_inode;
211 data->cred = req->wb_context->cred;
212
213 data->args.fh = NFS_FH(inode);
214 data->args.offset = req_offset(req) + offset;
215 data->args.pgbase = req->wb_pgbase + offset;
216 data->args.pages = data->pagevec;
217 data->args.count = count;
218 data->args.context = req->wb_context;
219
220 data->res.fattr = &data->fattr;
221 data->res.count = count;
222 data->res.eof = 0;
Trond Myklebust0e574af2005-10-27 22:12:38 -0400223 nfs_fattr_init(&data->fattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
Trond Myklebustec06c092006-03-20 13:44:27 -0500225 /* Set up the initial task struct. */
226 flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
227 rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 NFS_PROTO(inode)->read_setup(data);
229
230 data->task.tk_cookie = (unsigned long)inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
232 dprintk("NFS: %4d initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
233 data->task.tk_pid,
234 inode->i_sb->s_id,
235 (long long)NFS_FILEID(inode),
236 count,
237 (unsigned long long)data->args.offset);
238}
239
240static void
241nfs_async_read_error(struct list_head *head)
242{
243 struct nfs_page *req;
244
245 while (!list_empty(head)) {
246 req = nfs_list_entry(head->next);
247 nfs_list_remove_request(req);
248 SetPageError(req->wb_page);
249 nfs_readpage_release(req);
250 }
251}
252
253/*
254 * Start an async read operation
255 */
256static void nfs_execute_read(struct nfs_read_data *data)
257{
258 struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
259 sigset_t oldset;
260
261 rpc_clnt_sigmask(clnt, &oldset);
262 lock_kernel();
263 rpc_execute(&data->task);
264 unlock_kernel();
265 rpc_clnt_sigunmask(clnt, &oldset);
266}
267
268/*
269 * Generate multiple requests to fill a single page.
270 *
271 * We optimize to reduce the number of read operations on the wire. If we
272 * detect that we're reading a page, or an area of a page, that is past the
273 * end of file, we do not generate NFS read operations but just clear the
274 * parts of the page that would have come back zero from the server anyway.
275 *
276 * We rely on the cached value of i_size to make this determination; another
277 * client can fill pages on the server past our cached end-of-file, but we
278 * won't see the new data until our attribute cache is updated. This is more
279 * or less conventional NFS client behavior.
280 */
281static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
282{
283 struct nfs_page *req = nfs_list_entry(head->next);
284 struct page *page = req->wb_page;
285 struct nfs_read_data *data;
286 unsigned int rsize = NFS_SERVER(inode)->rsize;
287 unsigned int nbytes, offset;
288 int requests = 0;
289 LIST_HEAD(list);
290
291 nfs_list_remove_request(req);
292
293 nbytes = req->wb_bytes;
294 for(;;) {
Chuck Lever40859d72005-11-30 18:09:02 -0500295 data = nfs_readdata_alloc(1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 if (!data)
297 goto out_bad;
298 INIT_LIST_HEAD(&data->pages);
299 list_add(&data->pages, &list);
300 requests++;
301 if (nbytes <= rsize)
302 break;
303 nbytes -= rsize;
304 }
305 atomic_set(&req->wb_complete, requests);
306
307 ClearPageError(page);
308 offset = 0;
309 nbytes = req->wb_bytes;
310 do {
311 data = list_entry(list.next, struct nfs_read_data, pages);
312 list_del_init(&data->pages);
313
314 data->pagevec[0] = page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
316 if (nbytes > rsize) {
Trond Myklebustec06c092006-03-20 13:44:27 -0500317 nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
318 rsize, offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 offset += rsize;
320 nbytes -= rsize;
321 } else {
Trond Myklebustec06c092006-03-20 13:44:27 -0500322 nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
323 nbytes, offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 nbytes = 0;
325 }
326 nfs_execute_read(data);
327 } while (nbytes != 0);
328
329 return 0;
330
331out_bad:
332 while (!list_empty(&list)) {
333 data = list_entry(list.next, struct nfs_read_data, pages);
334 list_del(&data->pages);
335 nfs_readdata_free(data);
336 }
337 SetPageError(page);
338 nfs_readpage_release(req);
339 return -ENOMEM;
340}
341
342static int nfs_pagein_one(struct list_head *head, struct inode *inode)
343{
344 struct nfs_page *req;
345 struct page **pages;
346 struct nfs_read_data *data;
347 unsigned int count;
348
349 if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
350 return nfs_pagein_multi(head, inode);
351
Chuck Lever40859d72005-11-30 18:09:02 -0500352 data = nfs_readdata_alloc(NFS_SERVER(inode)->rpages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 if (!data)
354 goto out_bad;
355
356 INIT_LIST_HEAD(&data->pages);
357 pages = data->pagevec;
358 count = 0;
359 while (!list_empty(head)) {
360 req = nfs_list_entry(head->next);
361 nfs_list_remove_request(req);
362 nfs_list_add_request(req, &data->pages);
363 ClearPageError(req->wb_page);
364 *pages++ = req->wb_page;
365 count += req->wb_bytes;
366 }
367 req = nfs_list_entry(data->pages.next);
368
Trond Myklebustec06c092006-03-20 13:44:27 -0500369 nfs_read_rpcsetup(req, data, &nfs_read_full_ops, count, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370
371 nfs_execute_read(data);
372 return 0;
373out_bad:
374 nfs_async_read_error(head);
375 return -ENOMEM;
376}
377
378static int
379nfs_pagein_list(struct list_head *head, int rpages)
380{
381 LIST_HEAD(one_request);
382 struct nfs_page *req;
383 int error = 0;
384 unsigned int pages = 0;
385
386 while (!list_empty(head)) {
387 pages += nfs_coalesce_requests(head, &one_request, rpages);
388 req = nfs_list_entry(one_request.next);
389 error = nfs_pagein_one(&one_request, req->wb_context->dentry->d_inode);
390 if (error < 0)
391 break;
392 }
393 if (error >= 0)
394 return pages;
395
396 nfs_async_read_error(head);
397 return error;
398}
399
400/*
401 * Handle a read reply that fills part of a page.
402 */
Trond Myklebustec06c092006-03-20 13:44:27 -0500403static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404{
Trond Myklebustec06c092006-03-20 13:44:27 -0500405 struct nfs_read_data *data = calldata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 struct nfs_page *req = data->req;
407 struct page *page = req->wb_page;
408
Trond Myklebustec06c092006-03-20 13:44:27 -0500409 if (nfs_readpage_result(task, data) != 0)
410 return;
411 if (task->tk_status >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 unsigned int request = data->args.count;
413 unsigned int result = data->res.count;
414
415 if (result < request) {
416 memclear_highpage_flush(page,
417 data->args.pgbase + result,
418 request - result);
419 }
420 } else
421 SetPageError(page);
422
423 if (atomic_dec_and_test(&req->wb_complete)) {
424 if (!PageError(page))
425 SetPageUptodate(page);
426 nfs_readpage_release(req);
427 }
428}
429
Trond Myklebustec06c092006-03-20 13:44:27 -0500430static const struct rpc_call_ops nfs_read_partial_ops = {
431 .rpc_call_done = nfs_readpage_result_partial,
432 .rpc_release = nfs_readdata_release,
433};
434
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435/*
436 * This is the callback from RPC telling us whether a reply was
437 * received or some error occurred (timeout or socket shutdown).
438 */
Trond Myklebustec06c092006-03-20 13:44:27 -0500439static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440{
Trond Myklebustec06c092006-03-20 13:44:27 -0500441 struct nfs_read_data *data = calldata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 unsigned int count = data->res.count;
443
Trond Myklebustec06c092006-03-20 13:44:27 -0500444 if (nfs_readpage_result(task, data) != 0)
445 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 while (!list_empty(&data->pages)) {
447 struct nfs_page *req = nfs_list_entry(data->pages.next);
448 struct page *page = req->wb_page;
449 nfs_list_remove_request(req);
450
Trond Myklebustec06c092006-03-20 13:44:27 -0500451 if (task->tk_status >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 if (count < PAGE_CACHE_SIZE) {
453 if (count < req->wb_bytes)
454 memclear_highpage_flush(page,
455 req->wb_pgbase + count,
456 req->wb_bytes - count);
457 count = 0;
458 } else
459 count -= PAGE_CACHE_SIZE;
460 SetPageUptodate(page);
461 } else
462 SetPageError(page);
463 nfs_readpage_release(req);
464 }
465}
466
Trond Myklebustec06c092006-03-20 13:44:27 -0500467static const struct rpc_call_ops nfs_read_full_ops = {
468 .rpc_call_done = nfs_readpage_result_full,
469 .rpc_release = nfs_readdata_release,
470};
471
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472/*
473 * This is the callback from RPC telling us whether a reply was
474 * received or some error occurred (timeout or socket shutdown).
475 */
Trond Myklebustec06c092006-03-20 13:44:27 -0500476int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 struct nfs_readargs *argp = &data->args;
479 struct nfs_readres *resp = &data->res;
Trond Myklebustec06c092006-03-20 13:44:27 -0500480 int status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481
482 dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
Trond Myklebustec06c092006-03-20 13:44:27 -0500483 task->tk_pid, task->tk_status);
484
485 status = NFS_PROTO(data->inode)->read_done(task, data);
486 if (status != 0)
487 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
Chuck Lever91d5b472006-03-20 13:44:14 -0500489 nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, resp->count);
490
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 /* Is this a short read? */
492 if (task->tk_status >= 0 && resp->count < argp->count && !resp->eof) {
Chuck Lever91d5b472006-03-20 13:44:14 -0500493 nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 /* Has the server at least made some progress? */
495 if (resp->count != 0) {
496 /* Yes, so retry the read at the end of the data */
497 argp->offset += resp->count;
498 argp->pgbase += resp->count;
499 argp->count -= resp->count;
500 rpc_restart_call(task);
Trond Myklebustec06c092006-03-20 13:44:27 -0500501 return -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 }
503 task->tk_status = -EIO;
504 }
Chuck Leverdc592502005-08-18 11:24:12 -0700505 spin_lock(&data->inode->i_lock);
Chuck Lever55296802005-08-18 11:24:09 -0700506 NFS_I(data->inode)->cache_validity |= NFS_INO_INVALID_ATIME;
Chuck Leverdc592502005-08-18 11:24:12 -0700507 spin_unlock(&data->inode->i_lock);
Trond Myklebustec06c092006-03-20 13:44:27 -0500508 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509}
510
511/*
512 * Read a page over NFS.
513 * We read the page synchronously in the following case:
514 * - The error flag is set for this page. This happens only when a
515 * previous async read operation failed.
516 */
517int nfs_readpage(struct file *file, struct page *page)
518{
519 struct nfs_open_context *ctx;
520 struct inode *inode = page->mapping->host;
521 int error;
522
523 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
524 page, PAGE_CACHE_SIZE, page->index);
Chuck Lever91d5b472006-03-20 13:44:14 -0500525 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
526 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
527
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 /*
529 * Try to flush any pending writes to the file..
530 *
531 * NOTE! Because we own the page lock, there cannot
532 * be any new pending writes generated at this point
533 * for this page (other pages can be written to).
534 */
535 error = nfs_wb_page(inode, page);
536 if (error)
537 goto out_error;
538
539 if (file == NULL) {
Trond Myklebustd5308382005-11-04 15:33:38 -0500540 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 if (ctx == NULL)
542 return -EBADF;
543 } else
544 ctx = get_nfs_open_context((struct nfs_open_context *)
545 file->private_data);
546 if (!IS_SYNC(inode)) {
547 error = nfs_readpage_async(ctx, inode, page);
548 goto out;
549 }
550
551 error = nfs_readpage_sync(ctx, inode, page);
552 if (error < 0 && IS_SWAPFILE(inode))
553 printk("Aiee.. nfs swap-in of page failed!\n");
554out:
555 put_nfs_open_context(ctx);
556 return error;
557
558out_error:
559 unlock_page(page);
560 return error;
561}
562
563struct nfs_readdesc {
564 struct list_head *head;
565 struct nfs_open_context *ctx;
566};
567
568static int
569readpage_async_filler(void *data, struct page *page)
570{
571 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
572 struct inode *inode = page->mapping->host;
573 struct nfs_page *new;
574 unsigned int len;
575
576 nfs_wb_page(inode, page);
577 len = nfs_page_length(inode, page);
578 if (len == 0)
579 return nfs_return_empty_page(page);
580 new = nfs_create_request(desc->ctx, inode, page, 0, len);
581 if (IS_ERR(new)) {
582 SetPageError(page);
583 unlock_page(page);
584 return PTR_ERR(new);
585 }
586 if (len < PAGE_CACHE_SIZE)
587 memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 nfs_list_add_request(new, desc->head);
589 return 0;
590}
591
592int nfs_readpages(struct file *filp, struct address_space *mapping,
593 struct list_head *pages, unsigned nr_pages)
594{
595 LIST_HEAD(head);
596 struct nfs_readdesc desc = {
597 .head = &head,
598 };
599 struct inode *inode = mapping->host;
600 struct nfs_server *server = NFS_SERVER(inode);
601 int ret;
602
603 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
604 inode->i_sb->s_id,
605 (long long)NFS_FILEID(inode),
606 nr_pages);
Chuck Lever91d5b472006-03-20 13:44:14 -0500607 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
609 if (filp == NULL) {
Trond Myklebustd5308382005-11-04 15:33:38 -0500610 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 if (desc.ctx == NULL)
612 return -EBADF;
613 } else
614 desc.ctx = get_nfs_open_context((struct nfs_open_context *)
615 filp->private_data);
616 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
617 if (!list_empty(&head)) {
618 int err = nfs_pagein_list(&head, server->rpages);
619 if (!ret)
Chuck Lever91d5b472006-03-20 13:44:14 -0500620 nfs_add_stats(inode, NFSIOS_READPAGES, err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 ret = err;
622 }
623 put_nfs_open_context(desc.ctx);
624 return ret;
625}
626
627int nfs_init_readpagecache(void)
628{
629 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
630 sizeof(struct nfs_read_data),
631 0, SLAB_HWCACHE_ALIGN,
632 NULL, NULL);
633 if (nfs_rdata_cachep == NULL)
634 return -ENOMEM;
635
636 nfs_rdata_mempool = mempool_create(MIN_POOL_READ,
637 mempool_alloc_slab,
638 mempool_free_slab,
639 nfs_rdata_cachep);
640 if (nfs_rdata_mempool == NULL)
641 return -ENOMEM;
642
643 return 0;
644}
645
646void nfs_destroy_readpagecache(void)
647{
648 mempool_destroy(nfs_rdata_mempool);
649 if (kmem_cache_destroy(nfs_rdata_cachep))
650 printk(KERN_INFO "nfs_read_data: not all structures were freed\n");
651}