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David Howells14727282009-04-03 16:42:42 +01001/* 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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090020#include <linux/slab.h>
David Howells14727282009-04-03 16:42:42 +010021
22#include "internal.h"
David Howells545db452009-04-03 16:42:44 +010023#include "iostat.h"
David Howells14727282009-04-03 16:42:42 +010024#include "fscache.h"
25
26#define NFSDBG_FACILITY NFSDBG_FSCACHE
27
David Howells08734042009-04-03 16:42:42 +010028static struct rb_root nfs_fscache_keys = RB_ROOT;
29static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
30
David Howells14727282009-04-03 16:42:42 +010031/*
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,
David Howells94d30ae2013-09-21 00:09:31 +010042 clp, true);
David Howells14727282009-04-03 16:42:42 +010043 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}
David Howells08734042009-04-03 16:42:42 +010058
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.
David Howells2df54802009-09-23 14:36:39 -040062 *
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.
David Howells08734042009-04-03 16:42:42 +010066 */
Bryan Schumaker2311b942012-05-10 15:07:32 -040067void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
David Howells08734042009-04-03 16:42:42 +010068{
69 struct nfs_fscache_key *key, *xkey;
70 struct nfs_server *nfss = NFS_SB(sb);
71 struct rb_node **p, *parent;
Bryan Schumaker2311b942012-05-10 15:07:32 -040072 int diff;
David Howells2df54802009-09-23 14:36:39 -040073
74 if (!uniq) {
75 uniq = "";
76 ulen = 1;
77 }
78
David Howells08734042009-04-03 16:42:42 +010079 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,
David Howells94d30ae2013-09-21 00:09:31 +0100142 nfss, true);
David Howells08734042009-04-03 16:42:42 +0100143 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}
David Howellsef79c092009-04-03 16:42:43 +0100177
178/*
179 * Initialise the per-inode cache cookie pointer for an NFS inode.
180 */
David Howellsf1fe29b2013-09-27 11:20:03 +0100181void nfs_fscache_init_inode(struct inode *inode)
David Howellsef79c092009-04-03 16:42:43 +0100182{
David Howellsef79c092009-04-03 16:42:43 +0100183 struct nfs_inode *nfsi = NFS_I(inode);
184
David Howellsf1fe29b2013-09-27 11:20:03 +0100185 nfsi->fscache = NULL;
186 if (!S_ISREG(inode->i_mode))
David Howellsef79c092009-04-03 16:42:43 +0100187 return;
David Howellsf1fe29b2013-09-27 11:20:03 +0100188 nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
189 &nfs_fscache_inode_object_def,
190 nfsi, false);
David Howellsef79c092009-04-03 16:42:43 +0100191}
192
193/*
194 * Release a per-inode cookie.
195 */
David Howellsf1fe29b2013-09-27 11:20:03 +0100196void nfs_fscache_clear_inode(struct inode *inode)
David Howellsef79c092009-04-03 16:42:43 +0100197{
198 struct nfs_inode *nfsi = NFS_I(inode);
David Howellsf1fe29b2013-09-27 11:20:03 +0100199 struct fscache_cookie *cookie = nfs_i_fscache(inode);
David Howellsef79c092009-04-03 16:42:43 +0100200
David Howellsf1fe29b2013-09-27 11:20:03 +0100201 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
David Howellsef79c092009-04-03 16:42:43 +0100202
David Howellsf1fe29b2013-09-27 11:20:03 +0100203 fscache_relinquish_cookie(cookie, false);
David Howellsef79c092009-04-03 16:42:43 +0100204 nfsi->fscache = NULL;
205}
206
David Howellsf1fe29b2013-09-27 11:20:03 +0100207static bool nfs_fscache_can_enable(void *data)
David Howellsef79c092009-04-03 16:42:43 +0100208{
David Howellsf1fe29b2013-09-27 11:20:03 +0100209 struct inode *inode = data;
David Howellsef79c092009-04-03 16:42:43 +0100210
David Howellsf1fe29b2013-09-27 11:20:03 +0100211 return !inode_is_open_for_write(inode);
David Howellsef79c092009-04-03 16:42:43 +0100212}
213
214/*
David Howellsf1fe29b2013-09-27 11:20:03 +0100215 * Enable or disable caching for a file that is being opened as appropriate.
216 * The cookie is allocated when the inode is initialised, but is not enabled at
217 * that time. Enablement is deferred to file-open time to avoid stat() and
218 * access() thrashing the cache.
219 *
220 * For now, with NFS, only regular files that are open read-only will be able
221 * to use the cache.
222 *
223 * We enable the cache for an inode if we open it read-only and it isn't
224 * currently open for writing. We disable the cache if the inode is open
225 * write-only.
226 *
227 * The caller uses the file struct to pin i_writecount on the inode before
228 * calling us when a file is opened for writing, so we can make use of that.
229 *
230 * Note that this may be invoked multiple times in parallel by parallel
231 * nfs_open() functions.
David Howellsef79c092009-04-03 16:42:43 +0100232 */
David Howellsf1fe29b2013-09-27 11:20:03 +0100233void nfs_fscache_open_file(struct inode *inode, struct file *filp)
David Howellsef79c092009-04-03 16:42:43 +0100234{
David Howellsf1fe29b2013-09-27 11:20:03 +0100235 struct nfs_inode *nfsi = NFS_I(inode);
236 struct fscache_cookie *cookie = nfs_i_fscache(inode);
David Howellsef79c092009-04-03 16:42:43 +0100237
David Howellsf1fe29b2013-09-27 11:20:03 +0100238 if (!fscache_cookie_valid(cookie))
239 return;
David Howellsef79c092009-04-03 16:42:43 +0100240
David Howellsf1fe29b2013-09-27 11:20:03 +0100241 if (inode_is_open_for_write(inode)) {
242 dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
243 clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
244 fscache_disable_cookie(cookie, true);
245 fscache_uncache_all_inode_pages(cookie, inode);
246 } else {
247 dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
248 fscache_enable_cookie(cookie, nfs_fscache_can_enable, inode);
249 if (fscache_cookie_enabled(cookie))
250 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
David Howellsef79c092009-04-03 16:42:43 +0100251 }
252}
David Howellsf1fe29b2013-09-27 11:20:03 +0100253EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
David Howells545db452009-04-03 16:42:44 +0100254
255/*
256 * Release the caching state associated with a page, if the page isn't busy
257 * interacting with the cache.
258 * - Returns true (can release page) or false (page busy).
259 */
260int nfs_fscache_release_page(struct page *page, gfp_t gfp)
261{
David Howells545db452009-04-03 16:42:44 +0100262 if (PageFsCache(page)) {
David Howellsf1fe29b2013-09-27 11:20:03 +0100263 struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host);
Trond Myklebust2c174002010-02-08 09:32:27 -0500264
265 BUG_ON(!cookie);
David Howells545db452009-04-03 16:42:44 +0100266 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
David Howellsf1fe29b2013-09-27 11:20:03 +0100267 cookie, page, NFS_I(page->mapping->host));
David Howells545db452009-04-03 16:42:44 +0100268
David Howells201a1542009-11-19 18:11:35 +0000269 if (!fscache_maybe_release_page(cookie, page, gfp))
270 return 0;
271
Li RongQinge9f456c2014-11-23 12:47:41 +0800272 nfs_inc_fscache_stats(page->mapping->host,
273 NFSIOS_FSCACHE_PAGES_UNCACHED);
David Howells545db452009-04-03 16:42:44 +0100274 }
275
276 return 1;
277}
278
279/*
280 * Release the caching state associated with a page if undergoing complete page
281 * invalidation.
282 */
283void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
284{
David Howellsf1fe29b2013-09-27 11:20:03 +0100285 struct fscache_cookie *cookie = nfs_i_fscache(inode);
David Howells545db452009-04-03 16:42:44 +0100286
287 BUG_ON(!cookie);
288
289 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
David Howellsf1fe29b2013-09-27 11:20:03 +0100290 cookie, page, NFS_I(inode));
David Howells545db452009-04-03 16:42:44 +0100291
292 fscache_wait_on_page_write(cookie, page);
293
294 BUG_ON(!PageLocked(page));
295 fscache_uncache_page(cookie, page);
Li RongQinge9f456c2014-11-23 12:47:41 +0800296 nfs_inc_fscache_stats(page->mapping->host,
297 NFSIOS_FSCACHE_PAGES_UNCACHED);
David Howells545db452009-04-03 16:42:44 +0100298}
David Howells9a9fc1c2009-04-03 16:42:44 +0100299
300/*
301 * Handle completion of a page being read from the cache.
302 * - Called in process (keventd) context.
303 */
304static void nfs_readpage_from_fscache_complete(struct page *page,
305 void *context,
306 int error)
307{
308 dfprintk(FSCACHE,
309 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
310 page, context, error);
311
312 /* if the read completes with an error, we just unlock the page and let
313 * the VM reissue the readpage */
314 if (!error) {
315 SetPageUptodate(page);
316 unlock_page(page);
317 } else {
318 error = nfs_readpage_async(context, page->mapping->host, page);
319 if (error)
320 unlock_page(page);
321 }
322}
323
324/*
325 * Retrieve a page from fscache
326 */
327int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
328 struct inode *inode, struct page *page)
329{
330 int ret;
331
332 dfprintk(FSCACHE,
333 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
David Howellsf1fe29b2013-09-27 11:20:03 +0100334 nfs_i_fscache(inode), page, page->index, page->flags, inode);
David Howells9a9fc1c2009-04-03 16:42:44 +0100335
David Howellsf1fe29b2013-09-27 11:20:03 +0100336 ret = fscache_read_or_alloc_page(nfs_i_fscache(inode),
David Howells9a9fc1c2009-04-03 16:42:44 +0100337 page,
338 nfs_readpage_from_fscache_complete,
339 ctx,
340 GFP_KERNEL);
341
342 switch (ret) {
343 case 0: /* read BIO submitted (page in fscache) */
344 dfprintk(FSCACHE,
345 "NFS: readpage_from_fscache: BIO submitted\n");
Li RongQinge9f456c2014-11-23 12:47:41 +0800346 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
David Howells9a9fc1c2009-04-03 16:42:44 +0100347 return ret;
348
349 case -ENOBUFS: /* inode not in cache */
350 case -ENODATA: /* page not in cache */
Li RongQinge9f456c2014-11-23 12:47:41 +0800351 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
David Howells9a9fc1c2009-04-03 16:42:44 +0100352 dfprintk(FSCACHE,
353 "NFS: readpage_from_fscache %d\n", ret);
354 return 1;
355
356 default:
357 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
Li RongQinge9f456c2014-11-23 12:47:41 +0800358 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
David Howells9a9fc1c2009-04-03 16:42:44 +0100359 }
360 return ret;
361}
362
363/*
364 * Retrieve a set of pages from fscache
365 */
366int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
367 struct inode *inode,
368 struct address_space *mapping,
369 struct list_head *pages,
370 unsigned *nr_pages)
371{
Chuck Lever0f15c532010-05-07 13:33:48 -0400372 unsigned npages = *nr_pages;
373 int ret;
David Howells9a9fc1c2009-04-03 16:42:44 +0100374
375 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
David Howellsf1fe29b2013-09-27 11:20:03 +0100376 nfs_i_fscache(inode), npages, inode);
David Howells9a9fc1c2009-04-03 16:42:44 +0100377
David Howellsf1fe29b2013-09-27 11:20:03 +0100378 ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode),
David Howells9a9fc1c2009-04-03 16:42:44 +0100379 mapping, pages, nr_pages,
380 nfs_readpage_from_fscache_complete,
381 ctx,
382 mapping_gfp_mask(mapping));
383 if (*nr_pages < npages)
384 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
385 npages);
386 if (*nr_pages > 0)
387 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
388 *nr_pages);
389
390 switch (ret) {
391 case 0: /* read submitted to the cache for all pages */
392 BUG_ON(!list_empty(pages));
393 BUG_ON(*nr_pages != 0);
394 dfprintk(FSCACHE,
395 "NFS: nfs_getpages_from_fscache: submitted\n");
396
397 return ret;
398
399 case -ENOBUFS: /* some pages aren't cached and can't be */
400 case -ENODATA: /* some pages aren't cached */
401 dfprintk(FSCACHE,
402 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
403 return 1;
404
405 default:
406 dfprintk(FSCACHE,
407 "NFS: nfs_getpages_from_fscache: ret %d\n", ret);
408 }
409
410 return ret;
411}
David Howells7f8e05f2009-04-03 16:42:45 +0100412
413/*
414 * Store a newly fetched page in fscache
415 * - PG_fscache must be set on the page
416 */
417void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
418{
419 int ret;
420
421 dfprintk(FSCACHE,
422 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
David Howellsf1fe29b2013-09-27 11:20:03 +0100423 nfs_i_fscache(inode), page, page->index, page->flags, sync);
David Howells7f8e05f2009-04-03 16:42:45 +0100424
David Howellsf1fe29b2013-09-27 11:20:03 +0100425 ret = fscache_write_page(nfs_i_fscache(inode), page, GFP_KERNEL);
David Howells7f8e05f2009-04-03 16:42:45 +0100426 dfprintk(FSCACHE,
427 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
428 page, page->index, page->flags, ret);
429
430 if (ret != 0) {
David Howellsf1fe29b2013-09-27 11:20:03 +0100431 fscache_uncache_page(nfs_i_fscache(inode), page);
Li RongQinge9f456c2014-11-23 12:47:41 +0800432 nfs_inc_fscache_stats(inode,
433 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
434 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
David Howells7f8e05f2009-04-03 16:42:45 +0100435 } else {
Li RongQinge9f456c2014-11-23 12:47:41 +0800436 nfs_inc_fscache_stats(inode,
437 NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
David Howells7f8e05f2009-04-03 16:42:45 +0100438 }
439}