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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
28static struct rb_root nfs_fscache_keys = RB_ROOT;
29static 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 */
37void 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 */
50void 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 */
67void 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
147non_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 */
159void 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 */
181void 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 */
191static 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 */
213void 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 */
227void 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 */
243static 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 */
262static 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 */
271static 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 */
283static 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 */
299void 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
311/*
312 * Replace a per-inode cookie due to revalidation detecting a file having
313 * changed on the server.
314 */
315void nfs_fscache_reset_inode_cookie(struct inode *inode)
316{
317 struct nfs_inode *nfsi = NFS_I(inode);
318 struct nfs_server *nfss = NFS_SERVER(inode);
319 NFS_IFDEBUG(struct fscache_cookie *old = nfsi->fscache);
320
321 nfs_fscache_inode_lock(inode);
322 if (nfsi->fscache) {
323 /* retire the current fscache cache and get a new one */
324 fscache_relinquish_cookie(nfsi->fscache, 1);
325
326 nfsi->fscache = fscache_acquire_cookie(
327 nfss->nfs_client->fscache,
328 &nfs_fscache_inode_object_def,
329 nfsi);
330
331 dfprintk(FSCACHE,
332 "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
333 nfss, nfsi, old, nfsi->fscache);
334 }
335 nfs_fscache_inode_unlock(inode);
336}
337
338/*
339 * Release the caching state associated with a page, if the page isn't busy
340 * interacting with the cache.
341 * - Returns true (can release page) or false (page busy).
342 */
343int nfs_fscache_release_page(struct page *page, gfp_t gfp)
344{
345 if (PageFsCache(page)) {
346 struct nfs_inode *nfsi = NFS_I(page->mapping->host);
347 struct fscache_cookie *cookie = nfsi->fscache;
348
349 BUG_ON(!cookie);
350 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
351 cookie, page, nfsi);
352
353 if (!fscache_maybe_release_page(cookie, page, gfp))
354 return 0;
355
356 nfs_add_fscache_stats(page->mapping->host,
357 NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
358 }
359
360 return 1;
361}
362
363/*
364 * Release the caching state associated with a page if undergoing complete page
365 * invalidation.
366 */
367void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
368{
369 struct nfs_inode *nfsi = NFS_I(inode);
370 struct fscache_cookie *cookie = nfsi->fscache;
371
372 BUG_ON(!cookie);
373
374 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
375 cookie, page, nfsi);
376
377 fscache_wait_on_page_write(cookie, page);
378
379 BUG_ON(!PageLocked(page));
380 fscache_uncache_page(cookie, page);
381 nfs_add_fscache_stats(page->mapping->host,
382 NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
383}
384
385/*
386 * Handle completion of a page being read from the cache.
387 * - Called in process (keventd) context.
388 */
389static void nfs_readpage_from_fscache_complete(struct page *page,
390 void *context,
391 int error)
392{
393 dfprintk(FSCACHE,
394 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
395 page, context, error);
396
397 /* if the read completes with an error, we just unlock the page and let
398 * the VM reissue the readpage */
399 if (!error) {
400 SetPageUptodate(page);
401 unlock_page(page);
402 } else {
403 error = nfs_readpage_async(context, page->mapping->host, page);
404 if (error)
405 unlock_page(page);
406 }
407}
408
409/*
410 * Retrieve a page from fscache
411 */
412int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
413 struct inode *inode, struct page *page)
414{
415 int ret;
416
417 dfprintk(FSCACHE,
418 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
419 NFS_I(inode)->fscache, page, page->index, page->flags, inode);
420
421 ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache,
422 page,
423 nfs_readpage_from_fscache_complete,
424 ctx,
425 GFP_KERNEL);
426
427 switch (ret) {
428 case 0: /* read BIO submitted (page in fscache) */
429 dfprintk(FSCACHE,
430 "NFS: readpage_from_fscache: BIO submitted\n");
431 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1);
432 return ret;
433
434 case -ENOBUFS: /* inode not in cache */
435 case -ENODATA: /* page not in cache */
436 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
437 dfprintk(FSCACHE,
438 "NFS: readpage_from_fscache %d\n", ret);
439 return 1;
440
441 default:
442 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
443 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
444 }
445 return ret;
446}
447
448/*
449 * Retrieve a set of pages from fscache
450 */
451int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
452 struct inode *inode,
453 struct address_space *mapping,
454 struct list_head *pages,
455 unsigned *nr_pages)
456{
457 unsigned npages = *nr_pages;
458 int ret;
459
460 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
461 NFS_I(inode)->fscache, npages, inode);
462
463 ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache,
464 mapping, pages, nr_pages,
465 nfs_readpage_from_fscache_complete,
466 ctx,
467 mapping_gfp_mask(mapping));
468 if (*nr_pages < npages)
469 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
470 npages);
471 if (*nr_pages > 0)
472 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
473 *nr_pages);
474
475 switch (ret) {
476 case 0: /* read submitted to the cache for all pages */
477 BUG_ON(!list_empty(pages));
478 BUG_ON(*nr_pages != 0);
479 dfprintk(FSCACHE,
480 "NFS: nfs_getpages_from_fscache: submitted\n");
481
482 return ret;
483
484 case -ENOBUFS: /* some pages aren't cached and can't be */
485 case -ENODATA: /* some pages aren't cached */
486 dfprintk(FSCACHE,
487 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
488 return 1;
489
490 default:
491 dfprintk(FSCACHE,
492 "NFS: nfs_getpages_from_fscache: ret %d\n", ret);
493 }
494
495 return ret;
496}
497
498/*
499 * Store a newly fetched page in fscache
500 * - PG_fscache must be set on the page
501 */
502void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
503{
504 int ret;
505
506 dfprintk(FSCACHE,
507 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
508 NFS_I(inode)->fscache, page, page->index, page->flags, sync);
509
510 ret = fscache_write_page(NFS_I(inode)->fscache, page, GFP_KERNEL);
511 dfprintk(FSCACHE,
512 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
513 page, page->index, page->flags, ret);
514
515 if (ret != 0) {
516 fscache_uncache_page(NFS_I(inode)->fscache, page);
517 nfs_add_fscache_stats(inode,
518 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, 1);
519 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
520 } else {
521 nfs_add_fscache_stats(inode,
522 NFSIOS_FSCACHE_PAGES_WRITTEN_OK, 1);
523 }
524}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* NFS filesystem cache interface
3 *
4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/mm.h>
12#include <linux/nfs_fs.h>
13#include <linux/nfs_fs_sb.h>
14#include <linux/in6.h>
15#include <linux/seq_file.h>
16#include <linux/slab.h>
17#include <linux/iversion.h>
18
19#include "internal.h"
20#include "iostat.h"
21#include "fscache.h"
22
23#define NFSDBG_FACILITY NFSDBG_FSCACHE
24
25static struct rb_root nfs_fscache_keys = RB_ROOT;
26static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
27
28/*
29 * Layout of the key for an NFS server cache object.
30 */
31struct nfs_server_key {
32 struct {
33 uint16_t nfsversion; /* NFS protocol version */
34 uint32_t minorversion; /* NFSv4 minor version */
35 uint16_t family; /* address family */
36 __be16 port; /* IP port */
37 } hdr;
38 union {
39 struct in_addr ipv4_addr; /* IPv4 address */
40 struct in6_addr ipv6_addr; /* IPv6 address */
41 };
42} __packed;
43
44/*
45 * Get the per-client index cookie for an NFS client if the appropriate mount
46 * flag was set
47 * - We always try and get an index cookie for the client, but get filehandle
48 * cookies on a per-superblock basis, depending on the mount flags
49 */
50void nfs_fscache_get_client_cookie(struct nfs_client *clp)
51{
52 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
53 const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
54 struct nfs_server_key key;
55 uint16_t len = sizeof(key.hdr);
56
57 memset(&key, 0, sizeof(key));
58 key.hdr.nfsversion = clp->rpc_ops->version;
59 key.hdr.minorversion = clp->cl_minorversion;
60 key.hdr.family = clp->cl_addr.ss_family;
61
62 switch (clp->cl_addr.ss_family) {
63 case AF_INET:
64 key.hdr.port = sin->sin_port;
65 key.ipv4_addr = sin->sin_addr;
66 len += sizeof(key.ipv4_addr);
67 break;
68
69 case AF_INET6:
70 key.hdr.port = sin6->sin6_port;
71 key.ipv6_addr = sin6->sin6_addr;
72 len += sizeof(key.ipv6_addr);
73 break;
74
75 default:
76 printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
77 clp->cl_addr.ss_family);
78 clp->fscache = NULL;
79 return;
80 }
81
82 /* create a cache index for looking up filehandles */
83 clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
84 &nfs_fscache_server_index_def,
85 &key, len,
86 NULL, 0,
87 clp, 0, true);
88 dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
89 clp, clp->fscache);
90}
91
92/*
93 * Dispose of a per-client cookie
94 */
95void nfs_fscache_release_client_cookie(struct nfs_client *clp)
96{
97 dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
98 clp, clp->fscache);
99
100 fscache_relinquish_cookie(clp->fscache, NULL, false);
101 clp->fscache = NULL;
102}
103
104/*
105 * Get the cache cookie for an NFS superblock. We have to handle
106 * uniquification here because the cache doesn't do it for us.
107 *
108 * The default uniquifier is just an empty string, but it may be overridden
109 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
110 * superblock across an automount point of some nature.
111 */
112void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
113{
114 struct nfs_fscache_key *key, *xkey;
115 struct nfs_server *nfss = NFS_SB(sb);
116 struct rb_node **p, *parent;
117 int diff;
118
119 nfss->fscache_key = NULL;
120 nfss->fscache = NULL;
121 if (!uniq) {
122 uniq = "";
123 ulen = 1;
124 }
125
126 key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
127 if (!key)
128 return;
129
130 key->nfs_client = nfss->nfs_client;
131 key->key.super.s_flags = sb->s_flags & NFS_SB_MASK;
132 key->key.nfs_server.flags = nfss->flags;
133 key->key.nfs_server.rsize = nfss->rsize;
134 key->key.nfs_server.wsize = nfss->wsize;
135 key->key.nfs_server.acregmin = nfss->acregmin;
136 key->key.nfs_server.acregmax = nfss->acregmax;
137 key->key.nfs_server.acdirmin = nfss->acdirmin;
138 key->key.nfs_server.acdirmax = nfss->acdirmax;
139 key->key.nfs_server.fsid = nfss->fsid;
140 key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
141
142 key->key.uniq_len = ulen;
143 memcpy(key->key.uniquifier, uniq, ulen);
144
145 spin_lock(&nfs_fscache_keys_lock);
146 p = &nfs_fscache_keys.rb_node;
147 parent = NULL;
148 while (*p) {
149 parent = *p;
150 xkey = rb_entry(parent, struct nfs_fscache_key, node);
151
152 if (key->nfs_client < xkey->nfs_client)
153 goto go_left;
154 if (key->nfs_client > xkey->nfs_client)
155 goto go_right;
156
157 diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
158 if (diff < 0)
159 goto go_left;
160 if (diff > 0)
161 goto go_right;
162
163 if (key->key.uniq_len == 0)
164 goto non_unique;
165 diff = memcmp(key->key.uniquifier,
166 xkey->key.uniquifier,
167 key->key.uniq_len);
168 if (diff < 0)
169 goto go_left;
170 if (diff > 0)
171 goto go_right;
172 goto non_unique;
173
174 go_left:
175 p = &(*p)->rb_left;
176 continue;
177 go_right:
178 p = &(*p)->rb_right;
179 }
180
181 rb_link_node(&key->node, parent, p);
182 rb_insert_color(&key->node, &nfs_fscache_keys);
183 spin_unlock(&nfs_fscache_keys_lock);
184 nfss->fscache_key = key;
185
186 /* create a cache index for looking up filehandles */
187 nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
188 &nfs_fscache_super_index_def,
189 &key->key,
190 sizeof(key->key) + ulen,
191 NULL, 0,
192 nfss, 0, true);
193 dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
194 nfss, nfss->fscache);
195 return;
196
197non_unique:
198 spin_unlock(&nfs_fscache_keys_lock);
199 kfree(key);
200 nfss->fscache_key = NULL;
201 nfss->fscache = NULL;
202 printk(KERN_WARNING "NFS:"
203 " Cache request denied due to non-unique superblock keys\n");
204}
205
206/*
207 * release a per-superblock cookie
208 */
209void nfs_fscache_release_super_cookie(struct super_block *sb)
210{
211 struct nfs_server *nfss = NFS_SB(sb);
212
213 dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
214 nfss, nfss->fscache);
215
216 fscache_relinquish_cookie(nfss->fscache, NULL, false);
217 nfss->fscache = NULL;
218
219 if (nfss->fscache_key) {
220 spin_lock(&nfs_fscache_keys_lock);
221 rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
222 spin_unlock(&nfs_fscache_keys_lock);
223 kfree(nfss->fscache_key);
224 nfss->fscache_key = NULL;
225 }
226}
227
228static void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
229 struct nfs_inode *nfsi)
230{
231 memset(auxdata, 0, sizeof(*auxdata));
232 auxdata->mtime_sec = nfsi->vfs_inode.i_mtime.tv_sec;
233 auxdata->mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec;
234 auxdata->ctime_sec = nfsi->vfs_inode.i_ctime.tv_sec;
235 auxdata->ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec;
236
237 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
238 auxdata->change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
239}
240
241/*
242 * Initialise the per-inode cache cookie pointer for an NFS inode.
243 */
244void nfs_fscache_init_inode(struct inode *inode)
245{
246 struct nfs_fscache_inode_auxdata auxdata;
247 struct nfs_server *nfss = NFS_SERVER(inode);
248 struct nfs_inode *nfsi = NFS_I(inode);
249
250 nfsi->fscache = NULL;
251 if (!(nfss->fscache && S_ISREG(inode->i_mode)))
252 return;
253
254 nfs_fscache_update_auxdata(&auxdata, nfsi);
255
256 nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
257 &nfs_fscache_inode_object_def,
258 nfsi->fh.data, nfsi->fh.size,
259 &auxdata, sizeof(auxdata),
260 nfsi, nfsi->vfs_inode.i_size, false);
261}
262
263/*
264 * Release a per-inode cookie.
265 */
266void nfs_fscache_clear_inode(struct inode *inode)
267{
268 struct nfs_fscache_inode_auxdata auxdata;
269 struct nfs_inode *nfsi = NFS_I(inode);
270 struct fscache_cookie *cookie = nfs_i_fscache(inode);
271
272 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
273
274 nfs_fscache_update_auxdata(&auxdata, nfsi);
275 fscache_relinquish_cookie(cookie, &auxdata, false);
276 nfsi->fscache = NULL;
277}
278
279static bool nfs_fscache_can_enable(void *data)
280{
281 struct inode *inode = data;
282
283 return !inode_is_open_for_write(inode);
284}
285
286/*
287 * Enable or disable caching for a file that is being opened as appropriate.
288 * The cookie is allocated when the inode is initialised, but is not enabled at
289 * that time. Enablement is deferred to file-open time to avoid stat() and
290 * access() thrashing the cache.
291 *
292 * For now, with NFS, only regular files that are open read-only will be able
293 * to use the cache.
294 *
295 * We enable the cache for an inode if we open it read-only and it isn't
296 * currently open for writing. We disable the cache if the inode is open
297 * write-only.
298 *
299 * The caller uses the file struct to pin i_writecount on the inode before
300 * calling us when a file is opened for writing, so we can make use of that.
301 *
302 * Note that this may be invoked multiple times in parallel by parallel
303 * nfs_open() functions.
304 */
305void nfs_fscache_open_file(struct inode *inode, struct file *filp)
306{
307 struct nfs_fscache_inode_auxdata auxdata;
308 struct nfs_inode *nfsi = NFS_I(inode);
309 struct fscache_cookie *cookie = nfs_i_fscache(inode);
310
311 if (!fscache_cookie_valid(cookie))
312 return;
313
314 nfs_fscache_update_auxdata(&auxdata, nfsi);
315
316 if (inode_is_open_for_write(inode)) {
317 dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
318 clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
319 fscache_disable_cookie(cookie, &auxdata, true);
320 fscache_uncache_all_inode_pages(cookie, inode);
321 } else {
322 dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
323 fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size,
324 nfs_fscache_can_enable, inode);
325 if (fscache_cookie_enabled(cookie))
326 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
327 }
328}
329EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
330
331/*
332 * Release the caching state associated with a page, if the page isn't busy
333 * interacting with the cache.
334 * - Returns true (can release page) or false (page busy).
335 */
336int nfs_fscache_release_page(struct page *page, gfp_t gfp)
337{
338 if (PageFsCache(page)) {
339 struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host);
340
341 BUG_ON(!cookie);
342 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
343 cookie, page, NFS_I(page->mapping->host));
344
345 if (!fscache_maybe_release_page(cookie, page, gfp))
346 return 0;
347
348 nfs_inc_fscache_stats(page->mapping->host,
349 NFSIOS_FSCACHE_PAGES_UNCACHED);
350 }
351
352 return 1;
353}
354
355/*
356 * Release the caching state associated with a page if undergoing complete page
357 * invalidation.
358 */
359void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
360{
361 struct fscache_cookie *cookie = nfs_i_fscache(inode);
362
363 BUG_ON(!cookie);
364
365 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
366 cookie, page, NFS_I(inode));
367
368 fscache_wait_on_page_write(cookie, page);
369
370 BUG_ON(!PageLocked(page));
371 fscache_uncache_page(cookie, page);
372 nfs_inc_fscache_stats(page->mapping->host,
373 NFSIOS_FSCACHE_PAGES_UNCACHED);
374}
375
376/*
377 * Handle completion of a page being read from the cache.
378 * - Called in process (keventd) context.
379 */
380static void nfs_readpage_from_fscache_complete(struct page *page,
381 void *context,
382 int error)
383{
384 dfprintk(FSCACHE,
385 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
386 page, context, error);
387
388 /* if the read completes with an error, we just unlock the page and let
389 * the VM reissue the readpage */
390 if (!error) {
391 SetPageUptodate(page);
392 unlock_page(page);
393 } else {
394 error = nfs_readpage_async(context, page->mapping->host, page);
395 if (error)
396 unlock_page(page);
397 }
398}
399
400/*
401 * Retrieve a page from fscache
402 */
403int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
404 struct inode *inode, struct page *page)
405{
406 int ret;
407
408 dfprintk(FSCACHE,
409 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
410 nfs_i_fscache(inode), page, page->index, page->flags, inode);
411
412 ret = fscache_read_or_alloc_page(nfs_i_fscache(inode),
413 page,
414 nfs_readpage_from_fscache_complete,
415 ctx,
416 GFP_KERNEL);
417
418 switch (ret) {
419 case 0: /* read BIO submitted (page in fscache) */
420 dfprintk(FSCACHE,
421 "NFS: readpage_from_fscache: BIO submitted\n");
422 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
423 return ret;
424
425 case -ENOBUFS: /* inode not in cache */
426 case -ENODATA: /* page not in cache */
427 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
428 dfprintk(FSCACHE,
429 "NFS: readpage_from_fscache %d\n", ret);
430 return 1;
431
432 default:
433 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
434 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
435 }
436 return ret;
437}
438
439/*
440 * Retrieve a set of pages from fscache
441 */
442int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
443 struct inode *inode,
444 struct address_space *mapping,
445 struct list_head *pages,
446 unsigned *nr_pages)
447{
448 unsigned npages = *nr_pages;
449 int ret;
450
451 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
452 nfs_i_fscache(inode), npages, inode);
453
454 ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode),
455 mapping, pages, nr_pages,
456 nfs_readpage_from_fscache_complete,
457 ctx,
458 mapping_gfp_mask(mapping));
459 if (*nr_pages < npages)
460 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
461 npages);
462 if (*nr_pages > 0)
463 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
464 *nr_pages);
465
466 switch (ret) {
467 case 0: /* read submitted to the cache for all pages */
468 BUG_ON(!list_empty(pages));
469 BUG_ON(*nr_pages != 0);
470 dfprintk(FSCACHE,
471 "NFS: nfs_getpages_from_fscache: submitted\n");
472
473 return ret;
474
475 case -ENOBUFS: /* some pages aren't cached and can't be */
476 case -ENODATA: /* some pages aren't cached */
477 dfprintk(FSCACHE,
478 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
479 return 1;
480
481 default:
482 dfprintk(FSCACHE,
483 "NFS: nfs_getpages_from_fscache: ret %d\n", ret);
484 }
485
486 return ret;
487}
488
489/*
490 * Store a newly fetched page in fscache
491 * - PG_fscache must be set on the page
492 */
493void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
494{
495 int ret;
496
497 dfprintk(FSCACHE,
498 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
499 nfs_i_fscache(inode), page, page->index, page->flags, sync);
500
501 ret = fscache_write_page(nfs_i_fscache(inode), page,
502 inode->i_size, GFP_KERNEL);
503 dfprintk(FSCACHE,
504 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
505 page, page->index, page->flags, ret);
506
507 if (ret != 0) {
508 fscache_uncache_page(nfs_i_fscache(inode), page);
509 nfs_inc_fscache_stats(inode,
510 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
511 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
512 } else {
513 nfs_inc_fscache_stats(inode,
514 NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
515 }
516}