NFSv4: Fix lock recovery when CREATE_SESSION/SETCLIENTID_CONFIRM fails
[linux-3.10.git] / fs / nfs / fscache.c
1 /* NFS filesystem cache interface
2  *
3  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public Licence
8  * as published by the Free Software Foundation; either version
9  * 2 of the Licence, or (at your option) any later version.
10  */
11
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/nfs_fs.h>
17 #include <linux/nfs_fs_sb.h>
18 #include <linux/in6.h>
19 #include <linux/seq_file.h>
20 #include <linux/slab.h>
21
22 #include "internal.h"
23 #include "iostat.h"
24 #include "fscache.h"
25
26 #define NFSDBG_FACILITY         NFSDBG_FSCACHE
27
28 static struct rb_root nfs_fscache_keys = RB_ROOT;
29 static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
30
31 /*
32  * Get the per-client index cookie for an NFS client if the appropriate mount
33  * flag was set
34  * - We always try and get an index cookie for the client, but get filehandle
35  *   cookies on a per-superblock basis, depending on the mount flags
36  */
37 void nfs_fscache_get_client_cookie(struct nfs_client *clp)
38 {
39         /* create a cache index for looking up filehandles */
40         clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
41                                               &nfs_fscache_server_index_def,
42                                               clp);
43         dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
44                  clp, clp->fscache);
45 }
46
47 /*
48  * Dispose of a per-client cookie
49  */
50 void nfs_fscache_release_client_cookie(struct nfs_client *clp)
51 {
52         dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
53                  clp, clp->fscache);
54
55         fscache_relinquish_cookie(clp->fscache, 0);
56         clp->fscache = NULL;
57 }
58
59 /*
60  * Get the cache cookie for an NFS superblock.  We have to handle
61  * uniquification here because the cache doesn't do it for us.
62  *
63  * The default uniquifier is just an empty string, but it may be overridden
64  * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
65  * superblock across an automount point of some nature.
66  */
67 void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
68 {
69         struct nfs_fscache_key *key, *xkey;
70         struct nfs_server *nfss = NFS_SB(sb);
71         struct rb_node **p, *parent;
72         int diff;
73
74         if (!uniq) {
75                 uniq = "";
76                 ulen = 1;
77         }
78
79         key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
80         if (!key)
81                 return;
82
83         key->nfs_client = nfss->nfs_client;
84         key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
85         key->key.nfs_server.flags = nfss->flags;
86         key->key.nfs_server.rsize = nfss->rsize;
87         key->key.nfs_server.wsize = nfss->wsize;
88         key->key.nfs_server.acregmin = nfss->acregmin;
89         key->key.nfs_server.acregmax = nfss->acregmax;
90         key->key.nfs_server.acdirmin = nfss->acdirmin;
91         key->key.nfs_server.acdirmax = nfss->acdirmax;
92         key->key.nfs_server.fsid = nfss->fsid;
93         key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
94
95         key->key.uniq_len = ulen;
96         memcpy(key->key.uniquifier, uniq, ulen);
97
98         spin_lock(&nfs_fscache_keys_lock);
99         p = &nfs_fscache_keys.rb_node;
100         parent = NULL;
101         while (*p) {
102                 parent = *p;
103                 xkey = rb_entry(parent, struct nfs_fscache_key, node);
104
105                 if (key->nfs_client < xkey->nfs_client)
106                         goto go_left;
107                 if (key->nfs_client > xkey->nfs_client)
108                         goto go_right;
109
110                 diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
111                 if (diff < 0)
112                         goto go_left;
113                 if (diff > 0)
114                         goto go_right;
115
116                 if (key->key.uniq_len == 0)
117                         goto non_unique;
118                 diff = memcmp(key->key.uniquifier,
119                               xkey->key.uniquifier,
120                               key->key.uniq_len);
121                 if (diff < 0)
122                         goto go_left;
123                 if (diff > 0)
124                         goto go_right;
125                 goto non_unique;
126
127         go_left:
128                 p = &(*p)->rb_left;
129                 continue;
130         go_right:
131                 p = &(*p)->rb_right;
132         }
133
134         rb_link_node(&key->node, parent, p);
135         rb_insert_color(&key->node, &nfs_fscache_keys);
136         spin_unlock(&nfs_fscache_keys_lock);
137         nfss->fscache_key = key;
138
139         /* create a cache index for looking up filehandles */
140         nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
141                                                &nfs_fscache_super_index_def,
142                                                nfss);
143         dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
144                  nfss, nfss->fscache);
145         return;
146
147 non_unique:
148         spin_unlock(&nfs_fscache_keys_lock);
149         kfree(key);
150         nfss->fscache_key = NULL;
151         nfss->fscache = NULL;
152         printk(KERN_WARNING "NFS:"
153                " Cache request denied due to non-unique superblock keys\n");
154 }
155
156 /*
157  * release a per-superblock cookie
158  */
159 void nfs_fscache_release_super_cookie(struct super_block *sb)
160 {
161         struct nfs_server *nfss = NFS_SB(sb);
162
163         dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
164                  nfss, nfss->fscache);
165
166         fscache_relinquish_cookie(nfss->fscache, 0);
167         nfss->fscache = NULL;
168
169         if (nfss->fscache_key) {
170                 spin_lock(&nfs_fscache_keys_lock);
171                 rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
172                 spin_unlock(&nfs_fscache_keys_lock);
173                 kfree(nfss->fscache_key);
174                 nfss->fscache_key = NULL;
175         }
176 }
177
178 /*
179  * Initialise the per-inode cache cookie pointer for an NFS inode.
180  */
181 void nfs_fscache_init_inode_cookie(struct inode *inode)
182 {
183         NFS_I(inode)->fscache = NULL;
184         if (S_ISREG(inode->i_mode))
185                 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
186 }
187
188 /*
189  * Get the per-inode cache cookie for an NFS inode.
190  */
191 static void nfs_fscache_enable_inode_cookie(struct inode *inode)
192 {
193         struct super_block *sb = inode->i_sb;
194         struct nfs_inode *nfsi = NFS_I(inode);
195
196         if (nfsi->fscache || !NFS_FSCACHE(inode))
197                 return;
198
199         if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
200                 nfsi->fscache = fscache_acquire_cookie(
201                         NFS_SB(sb)->fscache,
202                         &nfs_fscache_inode_object_def,
203                         nfsi);
204
205                 dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
206                          sb, nfsi, nfsi->fscache);
207         }
208 }
209
210 /*
211  * Release a per-inode cookie.
212  */
213 void nfs_fscache_release_inode_cookie(struct inode *inode)
214 {
215         struct nfs_inode *nfsi = NFS_I(inode);
216
217         dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
218                  nfsi, nfsi->fscache);
219
220         fscache_relinquish_cookie(nfsi->fscache, 0);
221         nfsi->fscache = NULL;
222 }
223
224 /*
225  * Retire a per-inode cookie, destroying the data attached to it.
226  */
227 void nfs_fscache_zap_inode_cookie(struct inode *inode)
228 {
229         struct nfs_inode *nfsi = NFS_I(inode);
230
231         dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n",
232                  nfsi, nfsi->fscache);
233
234         fscache_relinquish_cookie(nfsi->fscache, 1);
235         nfsi->fscache = NULL;
236 }
237
238 /*
239  * Turn off the cache with regard to a per-inode cookie if opened for writing,
240  * invalidating all the pages in the page cache relating to the associated
241  * inode to clear the per-page caching.
242  */
243 static void nfs_fscache_disable_inode_cookie(struct inode *inode)
244 {
245         clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
246
247         if (NFS_I(inode)->fscache) {
248                 dfprintk(FSCACHE,
249                          "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
250
251                 /* Need to uncache any pages attached to this inode that
252                  * fscache knows about before turning off the cache.
253                  */
254                 fscache_uncache_all_inode_pages(NFS_I(inode)->fscache, inode);
255                 nfs_fscache_zap_inode_cookie(inode);
256         }
257 }
258
259 /*
260  * wait_on_bit() sleep function for uninterruptible waiting
261  */
262 static int nfs_fscache_wait_bit(void *flags)
263 {
264         schedule();
265         return 0;
266 }
267
268 /*
269  * Lock against someone else trying to also acquire or relinquish a cookie
270  */
271 static inline void nfs_fscache_inode_lock(struct inode *inode)
272 {
273         struct nfs_inode *nfsi = NFS_I(inode);
274
275         while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags))
276                 wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK,
277                             nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE);
278 }
279
280 /*
281  * Unlock cookie management lock
282  */
283 static inline void nfs_fscache_inode_unlock(struct inode *inode)
284 {
285         struct nfs_inode *nfsi = NFS_I(inode);
286
287         smp_mb__before_clear_bit();
288         clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags);
289         smp_mb__after_clear_bit();
290         wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK);
291 }
292
293 /*
294  * Decide if we should enable or disable local caching for this inode.
295  * - For now, with NFS, only regular files that are open read-only will be able
296  *   to use the cache.
297  * - May be invoked multiple times in parallel by parallel nfs_open() functions.
298  */
299 void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
300 {
301         if (NFS_FSCACHE(inode)) {
302                 nfs_fscache_inode_lock(inode);
303                 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
304                         nfs_fscache_disable_inode_cookie(inode);
305                 else
306                         nfs_fscache_enable_inode_cookie(inode);
307                 nfs_fscache_inode_unlock(inode);
308         }
309 }
310 EXPORT_SYMBOL_GPL(nfs_fscache_set_inode_cookie);
311
312 /*
313  * Replace a per-inode cookie due to revalidation detecting a file having
314  * changed on the server.
315  */
316 void nfs_fscache_reset_inode_cookie(struct inode *inode)
317 {
318         struct nfs_inode *nfsi = NFS_I(inode);
319         struct nfs_server *nfss = NFS_SERVER(inode);
320         NFS_IFDEBUG(struct fscache_cookie *old = nfsi->fscache);
321
322         nfs_fscache_inode_lock(inode);
323         if (nfsi->fscache) {
324                 /* retire the current fscache cache and get a new one */
325                 fscache_relinquish_cookie(nfsi->fscache, 1);
326
327                 nfsi->fscache = fscache_acquire_cookie(
328                         nfss->nfs_client->fscache,
329                         &nfs_fscache_inode_object_def,
330                         nfsi);
331
332                 dfprintk(FSCACHE,
333                          "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
334                          nfss, nfsi, old, nfsi->fscache);
335         }
336         nfs_fscache_inode_unlock(inode);
337 }
338
339 /*
340  * Release the caching state associated with a page, if the page isn't busy
341  * interacting with the cache.
342  * - Returns true (can release page) or false (page busy).
343  */
344 int nfs_fscache_release_page(struct page *page, gfp_t gfp)
345 {
346         if (PageFsCache(page)) {
347                 struct nfs_inode *nfsi = NFS_I(page->mapping->host);
348                 struct fscache_cookie *cookie = nfsi->fscache;
349
350                 BUG_ON(!cookie);
351                 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
352                          cookie, page, nfsi);
353
354                 if (!fscache_maybe_release_page(cookie, page, gfp))
355                         return 0;
356
357                 nfs_add_fscache_stats(page->mapping->host,
358                                       NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
359         }
360
361         return 1;
362 }
363
364 /*
365  * Release the caching state associated with a page if undergoing complete page
366  * invalidation.
367  */
368 void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
369 {
370         struct nfs_inode *nfsi = NFS_I(inode);
371         struct fscache_cookie *cookie = nfsi->fscache;
372
373         BUG_ON(!cookie);
374
375         dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
376                  cookie, page, nfsi);
377
378         fscache_wait_on_page_write(cookie, page);
379
380         BUG_ON(!PageLocked(page));
381         fscache_uncache_page(cookie, page);
382         nfs_add_fscache_stats(page->mapping->host,
383                               NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
384 }
385
386 /*
387  * Handle completion of a page being read from the cache.
388  * - Called in process (keventd) context.
389  */
390 static void nfs_readpage_from_fscache_complete(struct page *page,
391                                                void *context,
392                                                int error)
393 {
394         dfprintk(FSCACHE,
395                  "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
396                  page, context, error);
397
398         /* if the read completes with an error, we just unlock the page and let
399          * the VM reissue the readpage */
400         if (!error) {
401                 SetPageUptodate(page);
402                 unlock_page(page);
403         } else {
404                 error = nfs_readpage_async(context, page->mapping->host, page);
405                 if (error)
406                         unlock_page(page);
407         }
408 }
409
410 /*
411  * Retrieve a page from fscache
412  */
413 int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
414                                 struct inode *inode, struct page *page)
415 {
416         int ret;
417
418         dfprintk(FSCACHE,
419                  "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
420                  NFS_I(inode)->fscache, page, page->index, page->flags, inode);
421
422         ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache,
423                                          page,
424                                          nfs_readpage_from_fscache_complete,
425                                          ctx,
426                                          GFP_KERNEL);
427
428         switch (ret) {
429         case 0: /* read BIO submitted (page in fscache) */
430                 dfprintk(FSCACHE,
431                          "NFS:    readpage_from_fscache: BIO submitted\n");
432                 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1);
433                 return ret;
434
435         case -ENOBUFS: /* inode not in cache */
436         case -ENODATA: /* page not in cache */
437                 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
438                 dfprintk(FSCACHE,
439                          "NFS:    readpage_from_fscache %d\n", ret);
440                 return 1;
441
442         default:
443                 dfprintk(FSCACHE, "NFS:    readpage_from_fscache %d\n", ret);
444                 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
445         }
446         return ret;
447 }
448
449 /*
450  * Retrieve a set of pages from fscache
451  */
452 int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
453                                  struct inode *inode,
454                                  struct address_space *mapping,
455                                  struct list_head *pages,
456                                  unsigned *nr_pages)
457 {
458         unsigned npages = *nr_pages;
459         int ret;
460
461         dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
462                  NFS_I(inode)->fscache, npages, inode);
463
464         ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache,
465                                           mapping, pages, nr_pages,
466                                           nfs_readpage_from_fscache_complete,
467                                           ctx,
468                                           mapping_gfp_mask(mapping));
469         if (*nr_pages < npages)
470                 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
471                                       npages);
472         if (*nr_pages > 0)
473                 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
474                                       *nr_pages);
475
476         switch (ret) {
477         case 0: /* read submitted to the cache for all pages */
478                 BUG_ON(!list_empty(pages));
479                 BUG_ON(*nr_pages != 0);
480                 dfprintk(FSCACHE,
481                          "NFS: nfs_getpages_from_fscache: submitted\n");
482
483                 return ret;
484
485         case -ENOBUFS: /* some pages aren't cached and can't be */
486         case -ENODATA: /* some pages aren't cached */
487                 dfprintk(FSCACHE,
488                          "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
489                 return 1;
490
491         default:
492                 dfprintk(FSCACHE,
493                          "NFS: nfs_getpages_from_fscache: ret  %d\n", ret);
494         }
495
496         return ret;
497 }
498
499 /*
500  * Store a newly fetched page in fscache
501  * - PG_fscache must be set on the page
502  */
503 void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
504 {
505         int ret;
506
507         dfprintk(FSCACHE,
508                  "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
509                  NFS_I(inode)->fscache, page, page->index, page->flags, sync);
510
511         ret = fscache_write_page(NFS_I(inode)->fscache, page, GFP_KERNEL);
512         dfprintk(FSCACHE,
513                  "NFS:     readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
514                  page, page->index, page->flags, ret);
515
516         if (ret != 0) {
517                 fscache_uncache_page(NFS_I(inode)->fscache, page);
518                 nfs_add_fscache_stats(inode,
519                                       NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, 1);
520                 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
521         } else {
522                 nfs_add_fscache_stats(inode,
523                                       NFSIOS_FSCACHE_PAGES_WRITTEN_OK, 1);
524         }
525 }