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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
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>
15#include <linux/mm.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>
22
23#include "nfs4_fs.h"
24#include "internal.h"
25#include "iostat.h"
26#include "fscache.h"
27#include "pnfs.h"
28#include "nfstrace.h"
29
30#define NFSDBG_FACILITY NFSDBG_PAGECACHE
31
32static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
33static const struct nfs_rw_ops nfs_rw_read_ops;
34
35static struct kmem_cache *nfs_rdata_cachep;
36
37static struct nfs_pgio_header *nfs_readhdr_alloc(void)
38{
39 struct nfs_pgio_header *p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
40
41 if (p)
42 p->rw_mode = FMODE_READ;
43 return p;
44}
45
46static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
47{
48 kmem_cache_free(nfs_rdata_cachep, rhdr);
49}
50
51static
52int nfs_return_empty_page(struct page *page)
53{
54 zero_user(page, 0, PAGE_SIZE);
55 SetPageUptodate(page);
56 unlock_page(page);
57 return 0;
58}
59
60void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
61 struct inode *inode, bool force_mds,
62 const struct nfs_pgio_completion_ops *compl_ops)
63{
64 struct nfs_server *server = NFS_SERVER(inode);
65 const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
66
67#ifdef CONFIG_NFS_V4_1
68 if (server->pnfs_curr_ld && !force_mds)
69 pg_ops = server->pnfs_curr_ld->pg_read_ops;
70#endif
71 nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_read_ops,
72 server->rsize, 0);
73}
74EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
75
76void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
77{
78 struct nfs_pgio_mirror *mirror;
79
80 if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
81 pgio->pg_ops->pg_cleanup(pgio);
82
83 pgio->pg_ops = &nfs_pgio_rw_ops;
84
85 /* read path should never have more than one mirror */
86 WARN_ON_ONCE(pgio->pg_mirror_count != 1);
87
88 mirror = &pgio->pg_mirrors[0];
89 mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
90}
91EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
92
93static void nfs_readpage_release(struct nfs_page *req)
94{
95 struct inode *inode = d_inode(req->wb_context->dentry);
96
97 dprintk("NFS: read done (%s/%llu %d@%lld)\n", inode->i_sb->s_id,
98 (unsigned long long)NFS_FILEID(inode), req->wb_bytes,
99 (long long)req_offset(req));
100
101 if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE)) {
102 if (PageUptodate(req->wb_page))
103 nfs_readpage_to_fscache(inode, req->wb_page, 0);
104
105 unlock_page(req->wb_page);
106 }
107 nfs_release_request(req);
108}
109
110int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
111 struct page *page)
112{
113 struct nfs_page *new;
114 unsigned int len;
115 struct nfs_pageio_descriptor pgio;
116 struct nfs_pgio_mirror *pgm;
117
118 len = nfs_page_length(page);
119 if (len == 0)
120 return nfs_return_empty_page(page);
121 new = nfs_create_request(ctx, page, NULL, 0, len);
122 if (IS_ERR(new)) {
123 unlock_page(page);
124 return PTR_ERR(new);
125 }
126 if (len < PAGE_SIZE)
127 zero_user_segment(page, len, PAGE_SIZE);
128
129 nfs_pageio_init_read(&pgio, inode, false,
130 &nfs_async_read_completion_ops);
131 if (!nfs_pageio_add_request(&pgio, new)) {
132 nfs_list_remove_request(new);
133 nfs_readpage_release(new);
134 }
135 nfs_pageio_complete(&pgio);
136
137 /* It doesn't make sense to do mirrored reads! */
138 WARN_ON_ONCE(pgio.pg_mirror_count != 1);
139
140 pgm = &pgio.pg_mirrors[0];
141 NFS_I(inode)->read_io += pgm->pg_bytes_written;
142
143 return pgio.pg_error < 0 ? pgio.pg_error : 0;
144}
145
146static void nfs_page_group_set_uptodate(struct nfs_page *req)
147{
148 if (nfs_page_group_sync_on_bit(req, PG_UPTODATE))
149 SetPageUptodate(req->wb_page);
150}
151
152static void nfs_read_completion(struct nfs_pgio_header *hdr)
153{
154 unsigned long bytes = 0;
155
156 if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
157 goto out;
158 while (!list_empty(&hdr->pages)) {
159 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
160 struct page *page = req->wb_page;
161 unsigned long start = req->wb_pgbase;
162 unsigned long end = req->wb_pgbase + req->wb_bytes;
163
164 if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
165 /* note: regions of the page not covered by a
166 * request are zeroed in nfs_readpage_async /
167 * readpage_async_filler */
168 if (bytes > hdr->good_bytes) {
169 /* nothing in this request was good, so zero
170 * the full extent of the request */
171 zero_user_segment(page, start, end);
172
173 } else if (hdr->good_bytes - bytes < req->wb_bytes) {
174 /* part of this request has good bytes, but
175 * not all. zero the bad bytes */
176 start += hdr->good_bytes - bytes;
177 WARN_ON(start < req->wb_pgbase);
178 zero_user_segment(page, start, end);
179 }
180 }
181 bytes += req->wb_bytes;
182 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
183 if (bytes <= hdr->good_bytes)
184 nfs_page_group_set_uptodate(req);
185 } else
186 nfs_page_group_set_uptodate(req);
187 nfs_list_remove_request(req);
188 nfs_readpage_release(req);
189 }
190out:
191 hdr->release(hdr);
192}
193
194static void nfs_initiate_read(struct nfs_pgio_header *hdr,
195 struct rpc_message *msg,
196 const struct nfs_rpc_ops *rpc_ops,
197 struct rpc_task_setup *task_setup_data, int how)
198{
199 struct inode *inode = hdr->inode;
200 int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
201
202 task_setup_data->flags |= swap_flags;
203 rpc_ops->read_setup(hdr, msg);
204 trace_nfs_initiate_read(inode, hdr->io_start, hdr->good_bytes);
205}
206
207static void
208nfs_async_read_error(struct list_head *head)
209{
210 struct nfs_page *req;
211
212 while (!list_empty(head)) {
213 req = nfs_list_entry(head->next);
214 nfs_list_remove_request(req);
215 nfs_readpage_release(req);
216 }
217}
218
219static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
220 .error_cleanup = nfs_async_read_error,
221 .completion = nfs_read_completion,
222};
223
224/*
225 * This is the callback from RPC telling us whether a reply was
226 * received or some error occurred (timeout or socket shutdown).
227 */
228static int nfs_readpage_done(struct rpc_task *task,
229 struct nfs_pgio_header *hdr,
230 struct inode *inode)
231{
232 int status = NFS_PROTO(inode)->read_done(task, hdr);
233 if (status != 0)
234 return status;
235
236 nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, hdr->res.count);
237 trace_nfs_readpage_done(inode, task->tk_status,
238 hdr->args.offset, hdr->res.eof);
239
240 if (task->tk_status == -ESTALE) {
241 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
242 nfs_mark_for_revalidate(inode);
243 }
244 return 0;
245}
246
247static void nfs_readpage_retry(struct rpc_task *task,
248 struct nfs_pgio_header *hdr)
249{
250 struct nfs_pgio_args *argp = &hdr->args;
251 struct nfs_pgio_res *resp = &hdr->res;
252
253 /* This is a short read! */
254 nfs_inc_stats(hdr->inode, NFSIOS_SHORTREAD);
255 /* Has the server at least made some progress? */
256 if (resp->count == 0) {
257 nfs_set_pgio_error(hdr, -EIO, argp->offset);
258 return;
259 }
260
261 /* For non rpc-based layout drivers, retry-through-MDS */
262 if (!task->tk_ops) {
263 hdr->pnfs_error = -EAGAIN;
264 return;
265 }
266
267 /* Yes, so retry the read at the end of the hdr */
268 hdr->mds_offset += resp->count;
269 argp->offset += resp->count;
270 argp->pgbase += resp->count;
271 argp->count -= resp->count;
272 rpc_restart_call_prepare(task);
273}
274
275static void nfs_readpage_result(struct rpc_task *task,
276 struct nfs_pgio_header *hdr)
277{
278 if (hdr->res.eof) {
279 loff_t bound;
280
281 bound = hdr->args.offset + hdr->res.count;
282 spin_lock(&hdr->lock);
283 if (bound < hdr->io_start + hdr->good_bytes) {
284 set_bit(NFS_IOHDR_EOF, &hdr->flags);
285 clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
286 hdr->good_bytes = bound - hdr->io_start;
287 }
288 spin_unlock(&hdr->lock);
289 } else if (hdr->res.count < hdr->args.count)
290 nfs_readpage_retry(task, hdr);
291}
292
293/*
294 * Read a page over NFS.
295 * We read the page synchronously in the following case:
296 * - The error flag is set for this page. This happens only when a
297 * previous async read operation failed.
298 */
299int nfs_readpage(struct file *file, struct page *page)
300{
301 struct nfs_open_context *ctx;
302 struct inode *inode = page_file_mapping(page)->host;
303 int error;
304
305 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
306 page, PAGE_SIZE, page_index(page));
307 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
308 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
309
310 /*
311 * Try to flush any pending writes to the file..
312 *
313 * NOTE! Because we own the page lock, there cannot
314 * be any new pending writes generated at this point
315 * for this page (other pages can be written to).
316 */
317 error = nfs_wb_page(inode, page);
318 if (error)
319 goto out_unlock;
320 if (PageUptodate(page))
321 goto out_unlock;
322
323 error = -ESTALE;
324 if (NFS_STALE(inode))
325 goto out_unlock;
326
327 if (file == NULL) {
328 error = -EBADF;
329 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
330 if (ctx == NULL)
331 goto out_unlock;
332 } else
333 ctx = get_nfs_open_context(nfs_file_open_context(file));
334
335 if (!IS_SYNC(inode)) {
336 error = nfs_readpage_from_fscache(ctx, inode, page);
337 if (error == 0)
338 goto out;
339 }
340
341 error = nfs_readpage_async(ctx, inode, page);
342
343out:
344 put_nfs_open_context(ctx);
345 return error;
346out_unlock:
347 unlock_page(page);
348 return error;
349}
350
351struct nfs_readdesc {
352 struct nfs_pageio_descriptor *pgio;
353 struct nfs_open_context *ctx;
354};
355
356static int
357readpage_async_filler(void *data, struct page *page)
358{
359 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
360 struct nfs_page *new;
361 unsigned int len;
362 int error;
363
364 len = nfs_page_length(page);
365 if (len == 0)
366 return nfs_return_empty_page(page);
367
368 new = nfs_create_request(desc->ctx, page, NULL, 0, len);
369 if (IS_ERR(new))
370 goto out_error;
371
372 if (len < PAGE_SIZE)
373 zero_user_segment(page, len, PAGE_SIZE);
374 if (!nfs_pageio_add_request(desc->pgio, new)) {
375 nfs_list_remove_request(new);
376 nfs_readpage_release(new);
377 error = desc->pgio->pg_error;
378 goto out;
379 }
380 return 0;
381out_error:
382 error = PTR_ERR(new);
383 unlock_page(page);
384out:
385 return error;
386}
387
388int nfs_readpages(struct file *filp, struct address_space *mapping,
389 struct list_head *pages, unsigned nr_pages)
390{
391 struct nfs_pageio_descriptor pgio;
392 struct nfs_pgio_mirror *pgm;
393 struct nfs_readdesc desc = {
394 .pgio = &pgio,
395 };
396 struct inode *inode = mapping->host;
397 unsigned long npages;
398 int ret = -ESTALE;
399
400 dprintk("NFS: nfs_readpages (%s/%Lu %d)\n",
401 inode->i_sb->s_id,
402 (unsigned long long)NFS_FILEID(inode),
403 nr_pages);
404 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
405
406 if (NFS_STALE(inode))
407 goto out;
408
409 if (filp == NULL) {
410 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
411 if (desc.ctx == NULL)
412 return -EBADF;
413 } else
414 desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
415
416 /* attempt to read as many of the pages as possible from the cache
417 * - this returns -ENOBUFS immediately if the cookie is negative
418 */
419 ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
420 pages, &nr_pages);
421 if (ret == 0)
422 goto read_complete; /* all pages were read */
423
424 nfs_pageio_init_read(&pgio, inode, false,
425 &nfs_async_read_completion_ops);
426
427 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
428 nfs_pageio_complete(&pgio);
429
430 /* It doesn't make sense to do mirrored reads! */
431 WARN_ON_ONCE(pgio.pg_mirror_count != 1);
432
433 pgm = &pgio.pg_mirrors[0];
434 NFS_I(inode)->read_io += pgm->pg_bytes_written;
435 npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >>
436 PAGE_SHIFT;
437 nfs_add_stats(inode, NFSIOS_READPAGES, npages);
438read_complete:
439 put_nfs_open_context(desc.ctx);
440out:
441 return ret;
442}
443
444int __init nfs_init_readpagecache(void)
445{
446 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
447 sizeof(struct nfs_pgio_header),
448 0, SLAB_HWCACHE_ALIGN,
449 NULL);
450 if (nfs_rdata_cachep == NULL)
451 return -ENOMEM;
452
453 return 0;
454}
455
456void nfs_destroy_readpagecache(void)
457{
458 kmem_cache_destroy(nfs_rdata_cachep);
459}
460
461static const struct nfs_rw_ops nfs_rw_read_ops = {
462 .rw_alloc_header = nfs_readhdr_alloc,
463 .rw_free_header = nfs_readhdr_free,
464 .rw_done = nfs_readpage_done,
465 .rw_result = nfs_readpage_result,
466 .rw_initiate = nfs_initiate_read,
467};
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
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>
15#include <linux/mm.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>
22
23#include "nfs4_fs.h"
24#include "internal.h"
25#include "iostat.h"
26#include "fscache.h"
27#include "pnfs.h"
28
29#define NFSDBG_FACILITY NFSDBG_PAGECACHE
30
31static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
32static const struct nfs_rw_ops nfs_rw_read_ops;
33
34static struct kmem_cache *nfs_rdata_cachep;
35
36static struct nfs_pgio_header *nfs_readhdr_alloc(void)
37{
38 return kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
39}
40
41static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
42{
43 kmem_cache_free(nfs_rdata_cachep, rhdr);
44}
45
46static
47int nfs_return_empty_page(struct page *page)
48{
49 zero_user(page, 0, PAGE_SIZE);
50 SetPageUptodate(page);
51 unlock_page(page);
52 return 0;
53}
54
55void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
56 struct inode *inode, bool force_mds,
57 const struct nfs_pgio_completion_ops *compl_ops)
58{
59 struct nfs_server *server = NFS_SERVER(inode);
60 const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
61
62#ifdef CONFIG_NFS_V4_1
63 if (server->pnfs_curr_ld && !force_mds)
64 pg_ops = server->pnfs_curr_ld->pg_read_ops;
65#endif
66 nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_read_ops,
67 server->rsize, 0);
68}
69EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
70
71void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
72{
73 struct nfs_pgio_mirror *mirror;
74
75 if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
76 pgio->pg_ops->pg_cleanup(pgio);
77
78 pgio->pg_ops = &nfs_pgio_rw_ops;
79
80 /* read path should never have more than one mirror */
81 WARN_ON_ONCE(pgio->pg_mirror_count != 1);
82
83 mirror = &pgio->pg_mirrors[0];
84 mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
85}
86EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
87
88static void nfs_readpage_release(struct nfs_page *req)
89{
90 struct inode *inode = d_inode(req->wb_context->dentry);
91
92 dprintk("NFS: read done (%s/%llu %d@%lld)\n", inode->i_sb->s_id,
93 (unsigned long long)NFS_FILEID(inode), req->wb_bytes,
94 (long long)req_offset(req));
95
96 if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE)) {
97 if (PageUptodate(req->wb_page))
98 nfs_readpage_to_fscache(inode, req->wb_page, 0);
99
100 unlock_page(req->wb_page);
101 }
102 nfs_release_request(req);
103}
104
105int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
106 struct page *page)
107{
108 struct nfs_page *new;
109 unsigned int len;
110 struct nfs_pageio_descriptor pgio;
111 struct nfs_pgio_mirror *pgm;
112
113 len = nfs_page_length(page);
114 if (len == 0)
115 return nfs_return_empty_page(page);
116 new = nfs_create_request(ctx, page, NULL, 0, len);
117 if (IS_ERR(new)) {
118 unlock_page(page);
119 return PTR_ERR(new);
120 }
121 if (len < PAGE_SIZE)
122 zero_user_segment(page, len, PAGE_SIZE);
123
124 nfs_pageio_init_read(&pgio, inode, false,
125 &nfs_async_read_completion_ops);
126 if (!nfs_pageio_add_request(&pgio, new)) {
127 nfs_list_remove_request(new);
128 nfs_readpage_release(new);
129 }
130 nfs_pageio_complete(&pgio);
131
132 /* It doesn't make sense to do mirrored reads! */
133 WARN_ON_ONCE(pgio.pg_mirror_count != 1);
134
135 pgm = &pgio.pg_mirrors[0];
136 NFS_I(inode)->read_io += pgm->pg_bytes_written;
137
138 return pgio.pg_error < 0 ? pgio.pg_error : 0;
139}
140
141static void nfs_page_group_set_uptodate(struct nfs_page *req)
142{
143 if (nfs_page_group_sync_on_bit(req, PG_UPTODATE))
144 SetPageUptodate(req->wb_page);
145}
146
147static void nfs_read_completion(struct nfs_pgio_header *hdr)
148{
149 unsigned long bytes = 0;
150
151 if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
152 goto out;
153 while (!list_empty(&hdr->pages)) {
154 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
155 struct page *page = req->wb_page;
156 unsigned long start = req->wb_pgbase;
157 unsigned long end = req->wb_pgbase + req->wb_bytes;
158
159 if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
160 /* note: regions of the page not covered by a
161 * request are zeroed in nfs_readpage_async /
162 * readpage_async_filler */
163 if (bytes > hdr->good_bytes) {
164 /* nothing in this request was good, so zero
165 * the full extent of the request */
166 zero_user_segment(page, start, end);
167
168 } else if (hdr->good_bytes - bytes < req->wb_bytes) {
169 /* part of this request has good bytes, but
170 * not all. zero the bad bytes */
171 start += hdr->good_bytes - bytes;
172 WARN_ON(start < req->wb_pgbase);
173 zero_user_segment(page, start, end);
174 }
175 }
176 bytes += req->wb_bytes;
177 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
178 if (bytes <= hdr->good_bytes)
179 nfs_page_group_set_uptodate(req);
180 } else
181 nfs_page_group_set_uptodate(req);
182 nfs_list_remove_request(req);
183 nfs_readpage_release(req);
184 }
185out:
186 hdr->release(hdr);
187}
188
189static void nfs_initiate_read(struct nfs_pgio_header *hdr,
190 struct rpc_message *msg,
191 const struct nfs_rpc_ops *rpc_ops,
192 struct rpc_task_setup *task_setup_data, int how)
193{
194 struct inode *inode = hdr->inode;
195 int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
196
197 task_setup_data->flags |= swap_flags;
198 rpc_ops->read_setup(hdr, msg);
199}
200
201static void
202nfs_async_read_error(struct list_head *head)
203{
204 struct nfs_page *req;
205
206 while (!list_empty(head)) {
207 req = nfs_list_entry(head->next);
208 nfs_list_remove_request(req);
209 nfs_readpage_release(req);
210 }
211}
212
213static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
214 .error_cleanup = nfs_async_read_error,
215 .completion = nfs_read_completion,
216};
217
218/*
219 * This is the callback from RPC telling us whether a reply was
220 * received or some error occurred (timeout or socket shutdown).
221 */
222static int nfs_readpage_done(struct rpc_task *task,
223 struct nfs_pgio_header *hdr,
224 struct inode *inode)
225{
226 int status = NFS_PROTO(inode)->read_done(task, hdr);
227 if (status != 0)
228 return status;
229
230 nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, hdr->res.count);
231
232 if (task->tk_status == -ESTALE) {
233 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
234 nfs_mark_for_revalidate(inode);
235 }
236 return 0;
237}
238
239static void nfs_readpage_retry(struct rpc_task *task,
240 struct nfs_pgio_header *hdr)
241{
242 struct nfs_pgio_args *argp = &hdr->args;
243 struct nfs_pgio_res *resp = &hdr->res;
244
245 /* This is a short read! */
246 nfs_inc_stats(hdr->inode, NFSIOS_SHORTREAD);
247 /* Has the server at least made some progress? */
248 if (resp->count == 0) {
249 nfs_set_pgio_error(hdr, -EIO, argp->offset);
250 return;
251 }
252
253 /* For non rpc-based layout drivers, retry-through-MDS */
254 if (!task->tk_ops) {
255 hdr->pnfs_error = -EAGAIN;
256 return;
257 }
258
259 /* Yes, so retry the read at the end of the hdr */
260 hdr->mds_offset += resp->count;
261 argp->offset += resp->count;
262 argp->pgbase += resp->count;
263 argp->count -= resp->count;
264 rpc_restart_call_prepare(task);
265}
266
267static void nfs_readpage_result(struct rpc_task *task,
268 struct nfs_pgio_header *hdr)
269{
270 if (hdr->res.eof) {
271 loff_t bound;
272
273 bound = hdr->args.offset + hdr->res.count;
274 spin_lock(&hdr->lock);
275 if (bound < hdr->io_start + hdr->good_bytes) {
276 set_bit(NFS_IOHDR_EOF, &hdr->flags);
277 clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
278 hdr->good_bytes = bound - hdr->io_start;
279 }
280 spin_unlock(&hdr->lock);
281 } else if (hdr->res.count < hdr->args.count)
282 nfs_readpage_retry(task, hdr);
283}
284
285/*
286 * Read a page over NFS.
287 * We read the page synchronously in the following case:
288 * - The error flag is set for this page. This happens only when a
289 * previous async read operation failed.
290 */
291int nfs_readpage(struct file *file, struct page *page)
292{
293 struct nfs_open_context *ctx;
294 struct inode *inode = page_file_mapping(page)->host;
295 int error;
296
297 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
298 page, PAGE_SIZE, page_file_index(page));
299 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
300 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
301
302 /*
303 * Try to flush any pending writes to the file..
304 *
305 * NOTE! Because we own the page lock, there cannot
306 * be any new pending writes generated at this point
307 * for this page (other pages can be written to).
308 */
309 error = nfs_wb_page(inode, page);
310 if (error)
311 goto out_unlock;
312 if (PageUptodate(page))
313 goto out_unlock;
314
315 error = -ESTALE;
316 if (NFS_STALE(inode))
317 goto out_unlock;
318
319 if (file == NULL) {
320 error = -EBADF;
321 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
322 if (ctx == NULL)
323 goto out_unlock;
324 } else
325 ctx = get_nfs_open_context(nfs_file_open_context(file));
326
327 if (!IS_SYNC(inode)) {
328 error = nfs_readpage_from_fscache(ctx, inode, page);
329 if (error == 0)
330 goto out;
331 }
332
333 error = nfs_readpage_async(ctx, inode, page);
334
335out:
336 put_nfs_open_context(ctx);
337 return error;
338out_unlock:
339 unlock_page(page);
340 return error;
341}
342
343struct nfs_readdesc {
344 struct nfs_pageio_descriptor *pgio;
345 struct nfs_open_context *ctx;
346};
347
348static int
349readpage_async_filler(void *data, struct page *page)
350{
351 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
352 struct nfs_page *new;
353 unsigned int len;
354 int error;
355
356 len = nfs_page_length(page);
357 if (len == 0)
358 return nfs_return_empty_page(page);
359
360 new = nfs_create_request(desc->ctx, page, NULL, 0, len);
361 if (IS_ERR(new))
362 goto out_error;
363
364 if (len < PAGE_SIZE)
365 zero_user_segment(page, len, PAGE_SIZE);
366 if (!nfs_pageio_add_request(desc->pgio, new)) {
367 nfs_list_remove_request(new);
368 nfs_readpage_release(new);
369 error = desc->pgio->pg_error;
370 goto out_unlock;
371 }
372 return 0;
373out_error:
374 error = PTR_ERR(new);
375out_unlock:
376 unlock_page(page);
377 return error;
378}
379
380int nfs_readpages(struct file *filp, struct address_space *mapping,
381 struct list_head *pages, unsigned nr_pages)
382{
383 struct nfs_pageio_descriptor pgio;
384 struct nfs_pgio_mirror *pgm;
385 struct nfs_readdesc desc = {
386 .pgio = &pgio,
387 };
388 struct inode *inode = mapping->host;
389 unsigned long npages;
390 int ret = -ESTALE;
391
392 dprintk("NFS: nfs_readpages (%s/%Lu %d)\n",
393 inode->i_sb->s_id,
394 (unsigned long long)NFS_FILEID(inode),
395 nr_pages);
396 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
397
398 if (NFS_STALE(inode))
399 goto out;
400
401 if (filp == NULL) {
402 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
403 if (desc.ctx == NULL)
404 return -EBADF;
405 } else
406 desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
407
408 /* attempt to read as many of the pages as possible from the cache
409 * - this returns -ENOBUFS immediately if the cookie is negative
410 */
411 ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
412 pages, &nr_pages);
413 if (ret == 0)
414 goto read_complete; /* all pages were read */
415
416 nfs_pageio_init_read(&pgio, inode, false,
417 &nfs_async_read_completion_ops);
418
419 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
420 nfs_pageio_complete(&pgio);
421
422 /* It doesn't make sense to do mirrored reads! */
423 WARN_ON_ONCE(pgio.pg_mirror_count != 1);
424
425 pgm = &pgio.pg_mirrors[0];
426 NFS_I(inode)->read_io += pgm->pg_bytes_written;
427 npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >>
428 PAGE_SHIFT;
429 nfs_add_stats(inode, NFSIOS_READPAGES, npages);
430read_complete:
431 put_nfs_open_context(desc.ctx);
432out:
433 return ret;
434}
435
436int __init nfs_init_readpagecache(void)
437{
438 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
439 sizeof(struct nfs_pgio_header),
440 0, SLAB_HWCACHE_ALIGN,
441 NULL);
442 if (nfs_rdata_cachep == NULL)
443 return -ENOMEM;
444
445 return 0;
446}
447
448void nfs_destroy_readpagecache(void)
449{
450 kmem_cache_destroy(nfs_rdata_cachep);
451}
452
453static const struct nfs_rw_ops nfs_rw_read_ops = {
454 .rw_mode = FMODE_READ,
455 .rw_alloc_header = nfs_readhdr_alloc,
456 .rw_free_header = nfs_readhdr_free,
457 .rw_done = nfs_readpage_done,
458 .rw_result = nfs_readpage_result,
459 .rw_initiate = nfs_initiate_read,
460};