aboutsummaryrefslogtreecommitdiffstats
path: root/fs/fscache
diff options
context:
space:
mode:
Diffstat (limited to 'fs/fscache')
-rw-r--r--fs/fscache/Kconfig56
-rw-r--r--fs/fscache/Makefile19
-rw-r--r--fs/fscache/cache.c415
-rw-r--r--fs/fscache/cookie.c500
-rw-r--r--fs/fscache/fsdef.c144
-rw-r--r--fs/fscache/histogram.c109
-rw-r--r--fs/fscache/internal.h380
-rw-r--r--fs/fscache/main.c124
-rw-r--r--fs/fscache/netfs.c103
-rw-r--r--fs/fscache/object.c810
-rw-r--r--fs/fscache/operation.c459
-rw-r--r--fs/fscache/page.c816
-rw-r--r--fs/fscache/proc.c68
-rw-r--r--fs/fscache/stats.c212
14 files changed, 4215 insertions, 0 deletions
diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig
new file mode 100644
index 000000000000..9bbb8ce7bea0
--- /dev/null
+++ b/fs/fscache/Kconfig
@@ -0,0 +1,56 @@
1
2config FSCACHE
3 tristate "General filesystem local caching manager"
4 depends on EXPERIMENTAL
5 select SLOW_WORK
6 help
7 This option enables a generic filesystem caching manager that can be
8 used by various network and other filesystems to cache data locally.
9 Different sorts of caches can be plugged in, depending on the
10 resources available.
11
12 See Documentation/filesystems/caching/fscache.txt for more information.
13
14config FSCACHE_STATS
15 bool "Gather statistical information on local caching"
16 depends on FSCACHE && PROC_FS
17 help
18 This option causes statistical information to be gathered on local
19 caching and exported through file:
20
21 /proc/fs/fscache/stats
22
23 The gathering of statistics adds a certain amount of overhead to
24 execution as there are a quite a few stats gathered, and on a
25 multi-CPU system these may be on cachelines that keep bouncing
26 between CPUs. On the other hand, the stats are very useful for
27 debugging purposes. Saying 'Y' here is recommended.
28
29 See Documentation/filesystems/caching/fscache.txt for more information.
30
31config FSCACHE_HISTOGRAM
32 bool "Gather latency information on local caching"
33 depends on FSCACHE && PROC_FS
34 help
35 This option causes latency information to be gathered on local
36 caching and exported through file:
37
38 /proc/fs/fscache/histogram
39
40 The generation of this histogram adds a certain amount of overhead to
41 execution as there are a number of points at which data is gathered,
42 and on a multi-CPU system these may be on cachelines that keep
43 bouncing between CPUs. On the other hand, the histogram may be
44 useful for debugging purposes. Saying 'N' here is recommended.
45
46 See Documentation/filesystems/caching/fscache.txt for more information.
47
48config FSCACHE_DEBUG
49 bool "Debug FS-Cache"
50 depends on FSCACHE
51 help
52 This permits debugging to be dynamically enabled in the local caching
53 management module. If this is set, the debugging output may be
54 enabled by setting bits in /sys/modules/fscache/parameter/debug.
55
56 See Documentation/filesystems/caching/fscache.txt for more information.
diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile
new file mode 100644
index 000000000000..91571b95aacc
--- /dev/null
+++ b/fs/fscache/Makefile
@@ -0,0 +1,19 @@
1#
2# Makefile for general filesystem caching code
3#
4
5fscache-y := \
6 cache.o \
7 cookie.o \
8 fsdef.o \
9 main.o \
10 netfs.o \
11 object.o \
12 operation.o \
13 page.o
14
15fscache-$(CONFIG_PROC_FS) += proc.o
16fscache-$(CONFIG_FSCACHE_STATS) += stats.o
17fscache-$(CONFIG_FSCACHE_HISTOGRAM) += histogram.o
18
19obj-$(CONFIG_FSCACHE) := fscache.o
diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c
new file mode 100644
index 000000000000..e21985bbb1fb
--- /dev/null
+++ b/fs/fscache/cache.c
@@ -0,0 +1,415 @@
1/* FS-Cache cache handling
2 *
3 * Copyright (C) 2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL CACHE
13#include <linux/module.h>
14#include <linux/slab.h>
15#include "internal.h"
16
17LIST_HEAD(fscache_cache_list);
18DECLARE_RWSEM(fscache_addremove_sem);
19DECLARE_WAIT_QUEUE_HEAD(fscache_cache_cleared_wq);
20EXPORT_SYMBOL(fscache_cache_cleared_wq);
21
22static LIST_HEAD(fscache_cache_tag_list);
23
24/*
25 * look up a cache tag
26 */
27struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *name)
28{
29 struct fscache_cache_tag *tag, *xtag;
30
31 /* firstly check for the existence of the tag under read lock */
32 down_read(&fscache_addremove_sem);
33
34 list_for_each_entry(tag, &fscache_cache_tag_list, link) {
35 if (strcmp(tag->name, name) == 0) {
36 atomic_inc(&tag->usage);
37 up_read(&fscache_addremove_sem);
38 return tag;
39 }
40 }
41
42 up_read(&fscache_addremove_sem);
43
44 /* the tag does not exist - create a candidate */
45 xtag = kzalloc(sizeof(*xtag) + strlen(name) + 1, GFP_KERNEL);
46 if (!xtag)
47 /* return a dummy tag if out of memory */
48 return ERR_PTR(-ENOMEM);
49
50 atomic_set(&xtag->usage, 1);
51 strcpy(xtag->name, name);
52
53 /* write lock, search again and add if still not present */
54 down_write(&fscache_addremove_sem);
55
56 list_for_each_entry(tag, &fscache_cache_tag_list, link) {
57 if (strcmp(tag->name, name) == 0) {
58 atomic_inc(&tag->usage);
59 up_write(&fscache_addremove_sem);
60 kfree(xtag);
61 return tag;
62 }
63 }
64
65 list_add_tail(&xtag->link, &fscache_cache_tag_list);
66 up_write(&fscache_addremove_sem);
67 return xtag;
68}
69
70/*
71 * release a reference to a cache tag
72 */
73void __fscache_release_cache_tag(struct fscache_cache_tag *tag)
74{
75 if (tag != ERR_PTR(-ENOMEM)) {
76 down_write(&fscache_addremove_sem);
77
78 if (atomic_dec_and_test(&tag->usage))
79 list_del_init(&tag->link);
80 else
81 tag = NULL;
82
83 up_write(&fscache_addremove_sem);
84
85 kfree(tag);
86 }
87}
88
89/*
90 * select a cache in which to store an object
91 * - the cache addremove semaphore must be at least read-locked by the caller
92 * - the object will never be an index
93 */
94struct fscache_cache *fscache_select_cache_for_object(
95 struct fscache_cookie *cookie)
96{
97 struct fscache_cache_tag *tag;
98 struct fscache_object *object;
99 struct fscache_cache *cache;
100
101 _enter("");
102
103 if (list_empty(&fscache_cache_list)) {
104 _leave(" = NULL [no cache]");
105 return NULL;
106 }
107
108 /* we check the parent to determine the cache to use */
109 spin_lock(&cookie->lock);
110
111 /* the first in the parent's backing list should be the preferred
112 * cache */
113 if (!hlist_empty(&cookie->backing_objects)) {
114 object = hlist_entry(cookie->backing_objects.first,
115 struct fscache_object, cookie_link);
116
117 cache = object->cache;
118 if (object->state >= FSCACHE_OBJECT_DYING ||
119 test_bit(FSCACHE_IOERROR, &cache->flags))
120 cache = NULL;
121
122 spin_unlock(&cookie->lock);
123 _leave(" = %p [parent]", cache);
124 return cache;
125 }
126
127 /* the parent is unbacked */
128 if (cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) {
129 /* cookie not an index and is unbacked */
130 spin_unlock(&cookie->lock);
131 _leave(" = NULL [cookie ub,ni]");
132 return NULL;
133 }
134
135 spin_unlock(&cookie->lock);
136
137 if (!cookie->def->select_cache)
138 goto no_preference;
139
140 /* ask the netfs for its preference */
141 tag = cookie->def->select_cache(cookie->parent->netfs_data,
142 cookie->netfs_data);
143 if (!tag)
144 goto no_preference;
145
146 if (tag == ERR_PTR(-ENOMEM)) {
147 _leave(" = NULL [nomem tag]");
148 return NULL;
149 }
150
151 if (!tag->cache) {
152 _leave(" = NULL [unbacked tag]");
153 return NULL;
154 }
155
156 if (test_bit(FSCACHE_IOERROR, &tag->cache->flags))
157 return NULL;
158
159 _leave(" = %p [specific]", tag->cache);
160 return tag->cache;
161
162no_preference:
163 /* netfs has no preference - just select first cache */
164 cache = list_entry(fscache_cache_list.next,
165 struct fscache_cache, link);
166 _leave(" = %p [first]", cache);
167 return cache;
168}
169
170/**
171 * fscache_init_cache - Initialise a cache record
172 * @cache: The cache record to be initialised
173 * @ops: The cache operations to be installed in that record
174 * @idfmt: Format string to define identifier
175 * @...: sprintf-style arguments
176 *
177 * Initialise a record of a cache and fill in the name.
178 *
179 * See Documentation/filesystems/caching/backend-api.txt for a complete
180 * description.
181 */
182void fscache_init_cache(struct fscache_cache *cache,
183 const struct fscache_cache_ops *ops,
184 const char *idfmt,
185 ...)
186{
187 va_list va;
188
189 memset(cache, 0, sizeof(*cache));
190
191 cache->ops = ops;
192
193 va_start(va, idfmt);
194 vsnprintf(cache->identifier, sizeof(cache->identifier), idfmt, va);
195 va_end(va);
196
197 INIT_WORK(&cache->op_gc, fscache_operation_gc);
198 INIT_LIST_HEAD(&cache->link);
199 INIT_LIST_HEAD(&cache->object_list);
200 INIT_LIST_HEAD(&cache->op_gc_list);
201 spin_lock_init(&cache->object_list_lock);
202 spin_lock_init(&cache->op_gc_list_lock);
203}
204EXPORT_SYMBOL(fscache_init_cache);
205
206/**
207 * fscache_add_cache - Declare a cache as being open for business
208 * @cache: The record describing the cache
209 * @ifsdef: The record of the cache object describing the top-level index
210 * @tagname: The tag describing this cache
211 *
212 * Add a cache to the system, making it available for netfs's to use.
213 *
214 * See Documentation/filesystems/caching/backend-api.txt for a complete
215 * description.
216 */
217int fscache_add_cache(struct fscache_cache *cache,
218 struct fscache_object *ifsdef,
219 const char *tagname)
220{
221 struct fscache_cache_tag *tag;
222
223 BUG_ON(!cache->ops);
224 BUG_ON(!ifsdef);
225
226 cache->flags = 0;
227 ifsdef->event_mask = ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED);
228 ifsdef->state = FSCACHE_OBJECT_ACTIVE;
229
230 if (!tagname)
231 tagname = cache->identifier;
232
233 BUG_ON(!tagname[0]);
234
235 _enter("{%s.%s},,%s", cache->ops->name, cache->identifier, tagname);
236
237 /* we use the cache tag to uniquely identify caches */
238 tag = __fscache_lookup_cache_tag(tagname);
239 if (IS_ERR(tag))
240 goto nomem;
241
242 if (test_and_set_bit(FSCACHE_TAG_RESERVED, &tag->flags))
243 goto tag_in_use;
244
245 cache->kobj = kobject_create_and_add(tagname, fscache_root);
246 if (!cache->kobj)
247 goto error;
248
249 ifsdef->cookie = &fscache_fsdef_index;
250 ifsdef->cache = cache;
251 cache->fsdef = ifsdef;
252
253 down_write(&fscache_addremove_sem);
254
255 tag->cache = cache;
256 cache->tag = tag;
257
258 /* add the cache to the list */
259 list_add(&cache->link, &fscache_cache_list);
260
261 /* add the cache's netfs definition index object to the cache's
262 * list */
263 spin_lock(&cache->object_list_lock);
264 list_add_tail(&ifsdef->cache_link, &cache->object_list);
265 spin_unlock(&cache->object_list_lock);
266
267 /* add the cache's netfs definition index object to the top level index
268 * cookie as a known backing object */
269 spin_lock(&fscache_fsdef_index.lock);
270
271 hlist_add_head(&ifsdef->cookie_link,
272 &fscache_fsdef_index.backing_objects);
273
274 atomic_inc(&fscache_fsdef_index.usage);
275
276 /* done */
277 spin_unlock(&fscache_fsdef_index.lock);
278 up_write(&fscache_addremove_sem);
279
280 printk(KERN_NOTICE "FS-Cache: Cache \"%s\" added (type %s)\n",
281 cache->tag->name, cache->ops->name);
282 kobject_uevent(cache->kobj, KOBJ_ADD);
283
284 _leave(" = 0 [%s]", cache->identifier);
285 return 0;
286
287tag_in_use:
288 printk(KERN_ERR "FS-Cache: Cache tag '%s' already in use\n", tagname);
289 __fscache_release_cache_tag(tag);
290 _leave(" = -EXIST");
291 return -EEXIST;
292
293error:
294 __fscache_release_cache_tag(tag);
295 _leave(" = -EINVAL");
296 return -EINVAL;
297
298nomem:
299 _leave(" = -ENOMEM");
300 return -ENOMEM;
301}
302EXPORT_SYMBOL(fscache_add_cache);
303
304/**
305 * fscache_io_error - Note a cache I/O error
306 * @cache: The record describing the cache
307 *
308 * Note that an I/O error occurred in a cache and that it should no longer be
309 * used for anything. This also reports the error into the kernel log.
310 *
311 * See Documentation/filesystems/caching/backend-api.txt for a complete
312 * description.
313 */
314void fscache_io_error(struct fscache_cache *cache)
315{
316 set_bit(FSCACHE_IOERROR, &cache->flags);
317
318 printk(KERN_ERR "FS-Cache: Cache %s stopped due to I/O error\n",
319 cache->ops->name);
320}
321EXPORT_SYMBOL(fscache_io_error);
322
323/*
324 * request withdrawal of all the objects in a cache
325 * - all the objects being withdrawn are moved onto the supplied list
326 */
327static void fscache_withdraw_all_objects(struct fscache_cache *cache,
328 struct list_head *dying_objects)
329{
330 struct fscache_object *object;
331
332 spin_lock(&cache->object_list_lock);
333
334 while (!list_empty(&cache->object_list)) {
335 object = list_entry(cache->object_list.next,
336 struct fscache_object, cache_link);
337 list_move_tail(&object->cache_link, dying_objects);
338
339 _debug("withdraw %p", object->cookie);
340
341 spin_lock(&object->lock);
342 spin_unlock(&cache->object_list_lock);
343 fscache_raise_event(object, FSCACHE_OBJECT_EV_WITHDRAW);
344 spin_unlock(&object->lock);
345
346 cond_resched();
347 spin_lock(&cache->object_list_lock);
348 }
349
350 spin_unlock(&cache->object_list_lock);
351}
352
353/**
354 * fscache_withdraw_cache - Withdraw a cache from the active service
355 * @cache: The record describing the cache
356 *
357 * Withdraw a cache from service, unbinding all its cache objects from the
358 * netfs cookies they're currently representing.
359 *
360 * See Documentation/filesystems/caching/backend-api.txt for a complete
361 * description.
362 */
363void fscache_withdraw_cache(struct fscache_cache *cache)
364{
365 LIST_HEAD(dying_objects);
366
367 _enter("");
368
369 printk(KERN_NOTICE "FS-Cache: Withdrawing cache \"%s\"\n",
370 cache->tag->name);
371
372 /* make the cache unavailable for cookie acquisition */
373 if (test_and_set_bit(FSCACHE_CACHE_WITHDRAWN, &cache->flags))
374 BUG();
375
376 down_write(&fscache_addremove_sem);
377 list_del_init(&cache->link);
378 cache->tag->cache = NULL;
379 up_write(&fscache_addremove_sem);
380
381 /* make sure all pages pinned by operations on behalf of the netfs are
382 * written to disk */
383 cache->ops->sync_cache(cache);
384
385 /* dissociate all the netfs pages backed by this cache from the block
386 * mappings in the cache */
387 cache->ops->dissociate_pages(cache);
388
389 /* we now have to destroy all the active objects pertaining to this
390 * cache - which we do by passing them off to thread pool to be
391 * disposed of */
392 _debug("destroy");
393
394 fscache_withdraw_all_objects(cache, &dying_objects);
395
396 /* wait for all extant objects to finish their outstanding operations
397 * and go away */
398 _debug("wait for finish");
399 wait_event(fscache_cache_cleared_wq,
400 atomic_read(&cache->object_count) == 0);
401 _debug("wait for clearance");
402 wait_event(fscache_cache_cleared_wq,
403 list_empty(&cache->object_list));
404 _debug("cleared");
405 ASSERT(list_empty(&dying_objects));
406
407 kobject_put(cache->kobj);
408
409 clear_bit(FSCACHE_TAG_RESERVED, &cache->tag->flags);
410 fscache_release_cache_tag(cache->tag);
411 cache->tag = NULL;
412
413 _leave("");
414}
415EXPORT_SYMBOL(fscache_withdraw_cache);
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
new file mode 100644
index 000000000000..72fd18f6c71f
--- /dev/null
+++ b/fs/fscache/cookie.c
@@ -0,0 +1,500 @@
1/* netfs cookie management
2 *
3 * Copyright (C) 2004-2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * See Documentation/filesystems/caching/netfs-api.txt for more information on
12 * the netfs API.
13 */
14
15#define FSCACHE_DEBUG_LEVEL COOKIE
16#include <linux/module.h>
17#include <linux/slab.h>
18#include "internal.h"
19
20struct kmem_cache *fscache_cookie_jar;
21
22static atomic_t fscache_object_debug_id = ATOMIC_INIT(0);
23
24static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie);
25static int fscache_alloc_object(struct fscache_cache *cache,
26 struct fscache_cookie *cookie);
27static int fscache_attach_object(struct fscache_cookie *cookie,
28 struct fscache_object *object);
29
30/*
31 * initialise an cookie jar slab element prior to any use
32 */
33void fscache_cookie_init_once(void *_cookie)
34{
35 struct fscache_cookie *cookie = _cookie;
36
37 memset(cookie, 0, sizeof(*cookie));
38 spin_lock_init(&cookie->lock);
39 INIT_HLIST_HEAD(&cookie->backing_objects);
40}
41
42/*
43 * request a cookie to represent an object (index, datafile, xattr, etc)
44 * - parent specifies the parent object
45 * - the top level index cookie for each netfs is stored in the fscache_netfs
46 * struct upon registration
47 * - def points to the definition
48 * - the netfs_data will be passed to the functions pointed to in *def
49 * - all attached caches will be searched to see if they contain this object
50 * - index objects aren't stored on disk until there's a dependent file that
51 * needs storing
52 * - other objects are stored in a selected cache immediately, and all the
53 * indices forming the path to it are instantiated if necessary
54 * - we never let on to the netfs about errors
55 * - we may set a negative cookie pointer, but that's okay
56 */
57struct fscache_cookie *__fscache_acquire_cookie(
58 struct fscache_cookie *parent,
59 const struct fscache_cookie_def *def,
60 void *netfs_data)
61{
62 struct fscache_cookie *cookie;
63
64 BUG_ON(!def);
65
66 _enter("{%s},{%s},%p",
67 parent ? (char *) parent->def->name : "<no-parent>",
68 def->name, netfs_data);
69
70 fscache_stat(&fscache_n_acquires);
71
72 /* if there's no parent cookie, then we don't create one here either */
73 if (!parent) {
74 fscache_stat(&fscache_n_acquires_null);
75 _leave(" [no parent]");
76 return NULL;
77 }
78
79 /* validate the definition */
80 BUG_ON(!def->get_key);
81 BUG_ON(!def->name[0]);
82
83 BUG_ON(def->type == FSCACHE_COOKIE_TYPE_INDEX &&
84 parent->def->type != FSCACHE_COOKIE_TYPE_INDEX);
85
86 /* allocate and initialise a cookie */
87 cookie = kmem_cache_alloc(fscache_cookie_jar, GFP_KERNEL);
88 if (!cookie) {
89 fscache_stat(&fscache_n_acquires_oom);
90 _leave(" [ENOMEM]");
91 return NULL;
92 }
93
94 atomic_set(&cookie->usage, 1);
95 atomic_set(&cookie->n_children, 0);
96
97 atomic_inc(&parent->usage);
98 atomic_inc(&parent->n_children);
99
100 cookie->def = def;
101 cookie->parent = parent;
102 cookie->netfs_data = netfs_data;
103 cookie->flags = 0;
104
105 INIT_RADIX_TREE(&cookie->stores, GFP_NOFS);
106
107 switch (cookie->def->type) {
108 case FSCACHE_COOKIE_TYPE_INDEX:
109 fscache_stat(&fscache_n_cookie_index);
110 break;
111 case FSCACHE_COOKIE_TYPE_DATAFILE:
112 fscache_stat(&fscache_n_cookie_data);
113 break;
114 default:
115 fscache_stat(&fscache_n_cookie_special);
116 break;
117 }
118
119 /* if the object is an index then we need do nothing more here - we
120 * create indices on disk when we need them as an index may exist in
121 * multiple caches */
122 if (cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) {
123 if (fscache_acquire_non_index_cookie(cookie) < 0) {
124 atomic_dec(&parent->n_children);
125 __fscache_cookie_put(cookie);
126 fscache_stat(&fscache_n_acquires_nobufs);
127 _leave(" = NULL");
128 return NULL;
129 }
130 }
131
132 fscache_stat(&fscache_n_acquires_ok);
133 _leave(" = %p", cookie);
134 return cookie;
135}
136EXPORT_SYMBOL(__fscache_acquire_cookie);
137
138/*
139 * acquire a non-index cookie
140 * - this must make sure the index chain is instantiated and instantiate the
141 * object representation too
142 */
143static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie)
144{
145 struct fscache_object *object;
146 struct fscache_cache *cache;
147 uint64_t i_size;
148 int ret;
149
150 _enter("");
151
152 cookie->flags = 1 << FSCACHE_COOKIE_UNAVAILABLE;
153
154 /* now we need to see whether the backing objects for this cookie yet
155 * exist, if not there'll be nothing to search */
156 down_read(&fscache_addremove_sem);
157
158 if (list_empty(&fscache_cache_list)) {
159 up_read(&fscache_addremove_sem);
160 _leave(" = 0 [no caches]");
161 return 0;
162 }
163
164 /* select a cache in which to store the object */
165 cache = fscache_select_cache_for_object(cookie->parent);
166 if (!cache) {
167 up_read(&fscache_addremove_sem);
168 fscache_stat(&fscache_n_acquires_no_cache);
169 _leave(" = -ENOMEDIUM [no cache]");
170 return -ENOMEDIUM;
171 }
172
173 _debug("cache %s", cache->tag->name);
174
175 cookie->flags =
176 (1 << FSCACHE_COOKIE_LOOKING_UP) |
177 (1 << FSCACHE_COOKIE_CREATING) |
178 (1 << FSCACHE_COOKIE_NO_DATA_YET);
179
180 /* ask the cache to allocate objects for this cookie and its parent
181 * chain */
182 ret = fscache_alloc_object(cache, cookie);
183 if (ret < 0) {
184 up_read(&fscache_addremove_sem);
185 _leave(" = %d", ret);
186 return ret;
187 }
188
189 /* pass on how big the object we're caching is supposed to be */
190 cookie->def->get_attr(cookie->netfs_data, &i_size);
191
192 spin_lock(&cookie->lock);
193 if (hlist_empty(&cookie->backing_objects)) {
194 spin_unlock(&cookie->lock);
195 goto unavailable;
196 }
197
198 object = hlist_entry(cookie->backing_objects.first,
199 struct fscache_object, cookie_link);
200
201 fscache_set_store_limit(object, i_size);
202
203 /* initiate the process of looking up all the objects in the chain
204 * (done by fscache_initialise_object()) */
205 fscache_enqueue_object(object);
206
207 spin_unlock(&cookie->lock);
208
209 /* we may be required to wait for lookup to complete at this point */
210 if (!fscache_defer_lookup) {
211 _debug("non-deferred lookup %p", &cookie->flags);
212 wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
213 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
214 _debug("complete");
215 if (test_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags))
216 goto unavailable;
217 }
218
219 up_read(&fscache_addremove_sem);
220 _leave(" = 0 [deferred]");
221 return 0;
222
223unavailable:
224 up_read(&fscache_addremove_sem);
225 _leave(" = -ENOBUFS");
226 return -ENOBUFS;
227}
228
229/*
230 * recursively allocate cache object records for a cookie/cache combination
231 * - caller must be holding the addremove sem
232 */
233static int fscache_alloc_object(struct fscache_cache *cache,
234 struct fscache_cookie *cookie)
235{
236 struct fscache_object *object;
237 struct hlist_node *_n;
238 int ret;
239
240 _enter("%p,%p{%s}", cache, cookie, cookie->def->name);
241
242 spin_lock(&cookie->lock);
243 hlist_for_each_entry(object, _n, &cookie->backing_objects,
244 cookie_link) {
245 if (object->cache == cache)
246 goto object_already_extant;
247 }
248 spin_unlock(&cookie->lock);
249
250 /* ask the cache to allocate an object (we may end up with duplicate
251 * objects at this stage, but we sort that out later) */
252 object = cache->ops->alloc_object(cache, cookie);
253 if (IS_ERR(object)) {
254 fscache_stat(&fscache_n_object_no_alloc);
255 ret = PTR_ERR(object);
256 goto error;
257 }
258
259 fscache_stat(&fscache_n_object_alloc);
260
261 object->debug_id = atomic_inc_return(&fscache_object_debug_id);
262
263 _debug("ALLOC OBJ%x: %s {%lx}",
264 object->debug_id, cookie->def->name, object->events);
265
266 ret = fscache_alloc_object(cache, cookie->parent);
267 if (ret < 0)
268 goto error_put;
269
270 /* only attach if we managed to allocate all we needed, otherwise
271 * discard the object we just allocated and instead use the one
272 * attached to the cookie */
273 if (fscache_attach_object(cookie, object) < 0)
274 cache->ops->put_object(object);
275
276 _leave(" = 0");
277 return 0;
278
279object_already_extant:
280 ret = -ENOBUFS;
281 if (object->state >= FSCACHE_OBJECT_DYING) {
282 spin_unlock(&cookie->lock);
283 goto error;
284 }
285 spin_unlock(&cookie->lock);
286 _leave(" = 0 [found]");
287 return 0;
288
289error_put:
290 cache->ops->put_object(object);
291error:
292 _leave(" = %d", ret);
293 return ret;
294}
295
296/*
297 * attach a cache object to a cookie
298 */
299static int fscache_attach_object(struct fscache_cookie *cookie,
300 struct fscache_object *object)
301{
302 struct fscache_object *p;
303 struct fscache_cache *cache = object->cache;
304 struct hlist_node *_n;
305 int ret;
306
307 _enter("{%s},{OBJ%x}", cookie->def->name, object->debug_id);
308
309 spin_lock(&cookie->lock);
310
311 /* there may be multiple initial creations of this object, but we only
312 * want one */
313 ret = -EEXIST;
314 hlist_for_each_entry(p, _n, &cookie->backing_objects, cookie_link) {
315 if (p->cache == object->cache) {
316 if (p->state >= FSCACHE_OBJECT_DYING)
317 ret = -ENOBUFS;
318 goto cant_attach_object;
319 }
320 }
321
322 /* pin the parent object */
323 spin_lock_nested(&cookie->parent->lock, 1);
324 hlist_for_each_entry(p, _n, &cookie->parent->backing_objects,
325 cookie_link) {
326 if (p->cache == object->cache) {
327 if (p->state >= FSCACHE_OBJECT_DYING) {
328 ret = -ENOBUFS;
329 spin_unlock(&cookie->parent->lock);
330 goto cant_attach_object;
331 }
332 object->parent = p;
333 spin_lock(&p->lock);
334 p->n_children++;
335 spin_unlock(&p->lock);
336 break;
337 }
338 }
339 spin_unlock(&cookie->parent->lock);
340
341 /* attach to the cache's object list */
342 if (list_empty(&object->cache_link)) {
343 spin_lock(&cache->object_list_lock);
344 list_add(&object->cache_link, &cache->object_list);
345 spin_unlock(&cache->object_list_lock);
346 }
347
348 /* attach to the cookie */
349 object->cookie = cookie;
350 atomic_inc(&cookie->usage);
351 hlist_add_head(&object->cookie_link, &cookie->backing_objects);
352 ret = 0;
353
354cant_attach_object:
355 spin_unlock(&cookie->lock);
356 _leave(" = %d", ret);
357 return ret;
358}
359
360/*
361 * update the index entries backing a cookie
362 */
363void __fscache_update_cookie(struct fscache_cookie *cookie)
364{
365 struct fscache_object *object;
366 struct hlist_node *_p;
367
368 fscache_stat(&fscache_n_updates);
369
370 if (!cookie) {
371 fscache_stat(&fscache_n_updates_null);
372 _leave(" [no cookie]");
373 return;
374 }
375
376 _enter("{%s}", cookie->def->name);
377
378 BUG_ON(!cookie->def->get_aux);
379
380 spin_lock(&cookie->lock);
381
382 /* update the index entry on disk in each cache backing this cookie */
383 hlist_for_each_entry(object, _p,
384 &cookie->backing_objects, cookie_link) {
385 fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE);
386 }
387
388 spin_unlock(&cookie->lock);
389 _leave("");
390}
391EXPORT_SYMBOL(__fscache_update_cookie);
392
393/*
394 * release a cookie back to the cache
395 * - the object will be marked as recyclable on disk if retire is true
396 * - all dependents of this cookie must have already been unregistered
397 * (indices/files/pages)
398 */
399void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
400{
401 struct fscache_cache *cache;
402 struct fscache_object *object;
403 unsigned long event;
404
405 fscache_stat(&fscache_n_relinquishes);
406
407 if (!cookie) {
408 fscache_stat(&fscache_n_relinquishes_null);
409 _leave(" [no cookie]");
410 return;
411 }
412
413 _enter("%p{%s,%p},%d",
414 cookie, cookie->def->name, cookie->netfs_data, retire);
415
416 if (atomic_read(&cookie->n_children) != 0) {
417 printk(KERN_ERR "FS-Cache: Cookie '%s' still has children\n",
418 cookie->def->name);
419 BUG();
420 }
421
422 /* wait for the cookie to finish being instantiated (or to fail) */
423 if (test_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) {
424 fscache_stat(&fscache_n_relinquishes_waitcrt);
425 wait_on_bit(&cookie->flags, FSCACHE_COOKIE_CREATING,
426 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
427 }
428
429 event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE;
430
431 /* detach pointers back to the netfs */
432 spin_lock(&cookie->lock);
433
434 cookie->netfs_data = NULL;
435 cookie->def = NULL;
436
437 /* break links with all the active objects */
438 while (!hlist_empty(&cookie->backing_objects)) {
439 object = hlist_entry(cookie->backing_objects.first,
440 struct fscache_object,
441 cookie_link);
442
443 _debug("RELEASE OBJ%x", object->debug_id);
444
445 /* detach each cache object from the object cookie */
446 spin_lock(&object->lock);
447 hlist_del_init(&object->cookie_link);
448
449 cache = object->cache;
450 object->cookie = NULL;
451 fscache_raise_event(object, event);
452 spin_unlock(&object->lock);
453
454 if (atomic_dec_and_test(&cookie->usage))
455 /* the cookie refcount shouldn't be reduced to 0 yet */
456 BUG();
457 }
458
459 spin_unlock(&cookie->lock);
460
461 if (cookie->parent) {
462 ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
463 ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);
464 atomic_dec(&cookie->parent->n_children);
465 }
466
467 /* finally dispose of the cookie */
468 ASSERTCMP(atomic_read(&cookie->usage), >, 0);
469 fscache_cookie_put(cookie);
470
471 _leave("");
472}
473EXPORT_SYMBOL(__fscache_relinquish_cookie);
474
475/*
476 * destroy a cookie
477 */
478void __fscache_cookie_put(struct fscache_cookie *cookie)
479{
480 struct fscache_cookie *parent;
481
482 _enter("%p", cookie);
483
484 for (;;) {
485 _debug("FREE COOKIE %p", cookie);
486 parent = cookie->parent;
487 BUG_ON(!hlist_empty(&cookie->backing_objects));
488 kmem_cache_free(fscache_cookie_jar, cookie);
489
490 if (!parent)
491 break;
492
493 cookie = parent;
494 BUG_ON(atomic_read(&cookie->usage) <= 0);
495 if (!atomic_dec_and_test(&cookie->usage))
496 break;
497 }
498
499 _leave("");
500}
diff --git a/fs/fscache/fsdef.c b/fs/fscache/fsdef.c
new file mode 100644
index 000000000000..f5b4baee7352
--- /dev/null
+++ b/fs/fscache/fsdef.c
@@ -0,0 +1,144 @@
1/* Filesystem index definition
2 *
3 * Copyright (C) 2004-2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL CACHE
13#include <linux/module.h>
14#include "internal.h"
15
16static uint16_t fscache_fsdef_netfs_get_key(const void *cookie_netfs_data,
17 void *buffer, uint16_t bufmax);
18
19static uint16_t fscache_fsdef_netfs_get_aux(const void *cookie_netfs_data,
20 void *buffer, uint16_t bufmax);
21
22static
23enum fscache_checkaux fscache_fsdef_netfs_check_aux(void *cookie_netfs_data,
24 const void *data,
25 uint16_t datalen);
26
27/*
28 * The root index is owned by FS-Cache itself.
29 *
30 * When a netfs requests caching facilities, FS-Cache will, if one doesn't
31 * already exist, create an entry in the root index with the key being the name
32 * of the netfs ("AFS" for example), and the auxiliary data holding the index
33 * structure version supplied by the netfs:
34 *
35 * FSDEF
36 * |
37 * +-----------+
38 * | |
39 * NFS AFS
40 * [v=1] [v=1]
41 *
42 * If an entry with the appropriate name does already exist, the version is
43 * compared. If the version is different, the entire subtree from that entry
44 * will be discarded and a new entry created.
45 *
46 * The new entry will be an index, and a cookie referring to it will be passed
47 * to the netfs. This is then the root handle by which the netfs accesses the
48 * cache. It can create whatever objects it likes in that index, including
49 * further indices.
50 */
51static struct fscache_cookie_def fscache_fsdef_index_def = {
52 .name = ".FS-Cache",
53 .type = FSCACHE_COOKIE_TYPE_INDEX,
54};
55
56struct fscache_cookie fscache_fsdef_index = {
57 .usage = ATOMIC_INIT(1),
58 .lock = __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock),
59 .backing_objects = HLIST_HEAD_INIT,
60 .def = &fscache_fsdef_index_def,
61};
62EXPORT_SYMBOL(fscache_fsdef_index);
63
64/*
65 * Definition of an entry in the root index. Each entry is an index, keyed to
66 * a specific netfs and only applicable to a particular version of the index
67 * structure used by that netfs.
68 */
69struct fscache_cookie_def fscache_fsdef_netfs_def = {
70 .name = "FSDEF.netfs",
71 .type = FSCACHE_COOKIE_TYPE_INDEX,
72 .get_key = fscache_fsdef_netfs_get_key,
73 .get_aux = fscache_fsdef_netfs_get_aux,
74 .check_aux = fscache_fsdef_netfs_check_aux,
75};
76
77/*
78 * get the key data for an FSDEF index record - this is the name of the netfs
79 * for which this entry is created
80 */
81static uint16_t fscache_fsdef_netfs_get_key(const void *cookie_netfs_data,
82 void *buffer, uint16_t bufmax)
83{
84 const struct fscache_netfs *netfs = cookie_netfs_data;
85 unsigned klen;
86
87 _enter("{%s.%u},", netfs->name, netfs->version);
88
89 klen = strlen(netfs->name);
90 if (klen > bufmax)
91 return 0;
92
93 memcpy(buffer, netfs->name, klen);
94 return klen;
95}
96
97/*
98 * get the auxiliary data for an FSDEF index record - this is the index
99 * structure version number of the netfs for which this version is created
100 */
101static uint16_t fscache_fsdef_netfs_get_aux(const void *cookie_netfs_data,
102 void *buffer, uint16_t bufmax)
103{
104 const struct fscache_netfs *netfs = cookie_netfs_data;
105 unsigned dlen;
106
107 _enter("{%s.%u},", netfs->name, netfs->version);
108
109 dlen = sizeof(uint32_t);
110 if (dlen > bufmax)
111 return 0;
112
113 memcpy(buffer, &netfs->version, dlen);
114 return dlen;
115}
116
117/*
118 * check that the index structure version number stored in the auxiliary data
119 * matches the one the netfs gave us
120 */
121static enum fscache_checkaux fscache_fsdef_netfs_check_aux(
122 void *cookie_netfs_data,
123 const void *data,
124 uint16_t datalen)
125{
126 struct fscache_netfs *netfs = cookie_netfs_data;
127 uint32_t version;
128
129 _enter("{%s},,%hu", netfs->name, datalen);
130
131 if (datalen != sizeof(version)) {
132 _leave(" = OBSOLETE [dl=%d v=%zu]", datalen, sizeof(version));
133 return FSCACHE_CHECKAUX_OBSOLETE;
134 }
135
136 memcpy(&version, data, sizeof(version));
137 if (version != netfs->version) {
138 _leave(" = OBSOLETE [ver=%x net=%x]", version, netfs->version);
139 return FSCACHE_CHECKAUX_OBSOLETE;
140 }
141
142 _leave(" = OKAY");
143 return FSCACHE_CHECKAUX_OKAY;
144}
diff --git a/fs/fscache/histogram.c b/fs/fscache/histogram.c
new file mode 100644
index 000000000000..bad496748a59
--- /dev/null
+++ b/fs/fscache/histogram.c
@@ -0,0 +1,109 @@
1/* FS-Cache latency histogram
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#define FSCACHE_DEBUG_LEVEL THREAD
13#include <linux/module.h>
14#include <linux/proc_fs.h>
15#include <linux/seq_file.h>
16#include "internal.h"
17
18atomic_t fscache_obj_instantiate_histogram[HZ];
19atomic_t fscache_objs_histogram[HZ];
20atomic_t fscache_ops_histogram[HZ];
21atomic_t fscache_retrieval_delay_histogram[HZ];
22atomic_t fscache_retrieval_histogram[HZ];
23
24/*
25 * display the time-taken histogram
26 */
27static int fscache_histogram_show(struct seq_file *m, void *v)
28{
29 unsigned long index;
30 unsigned n[5], t;
31
32 switch ((unsigned long) v) {
33 case 1:
34 seq_puts(m, "JIFS SECS OBJ INST OP RUNS OBJ RUNS "
35 " RETRV DLY RETRIEVLS\n");
36 return 0;
37 case 2:
38 seq_puts(m, "===== ===== ========= ========= ========="
39 " ========= =========\n");
40 return 0;
41 default:
42 index = (unsigned long) v - 3;
43 n[0] = atomic_read(&fscache_obj_instantiate_histogram[index]);
44 n[1] = atomic_read(&fscache_ops_histogram[index]);
45 n[2] = atomic_read(&fscache_objs_histogram[index]);
46 n[3] = atomic_read(&fscache_retrieval_delay_histogram[index]);
47 n[4] = atomic_read(&fscache_retrieval_histogram[index]);
48 if (!(n[0] | n[1] | n[2] | n[3] | n[4]))
49 return 0;
50
51 t = (index * 1000) / HZ;
52
53 seq_printf(m, "%4lu 0.%03u %9u %9u %9u %9u %9u\n",
54 index, t, n[0], n[1], n[2], n[3], n[4]);
55 return 0;
56 }
57}
58
59/*
60 * set up the iterator to start reading from the first line
61 */
62static void *fscache_histogram_start(struct seq_file *m, loff_t *_pos)
63{
64 if ((unsigned long long)*_pos >= HZ + 2)
65 return NULL;
66 if (*_pos == 0)
67 *_pos = 1;
68 return (void *)(unsigned long) *_pos;
69}
70
71/*
72 * move to the next line
73 */
74static void *fscache_histogram_next(struct seq_file *m, void *v, loff_t *pos)
75{
76 (*pos)++;
77 return (unsigned long long)*pos > HZ + 2 ?
78 NULL : (void *)(unsigned long) *pos;
79}
80
81/*
82 * clean up after reading
83 */
84static void fscache_histogram_stop(struct seq_file *m, void *v)
85{
86}
87
88static const struct seq_operations fscache_histogram_ops = {
89 .start = fscache_histogram_start,
90 .stop = fscache_histogram_stop,
91 .next = fscache_histogram_next,
92 .show = fscache_histogram_show,
93};
94
95/*
96 * open "/proc/fs/fscache/histogram" to provide latency data
97 */
98static int fscache_histogram_open(struct inode *inode, struct file *file)
99{
100 return seq_open(file, &fscache_histogram_ops);
101}
102
103const struct file_operations fscache_histogram_fops = {
104 .owner = THIS_MODULE,
105 .open = fscache_histogram_open,
106 .read = seq_read,
107 .llseek = seq_lseek,
108 .release = seq_release,
109};
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
new file mode 100644
index 000000000000..e0cbd16f6dc9
--- /dev/null
+++ b/fs/fscache/internal.h
@@ -0,0 +1,380 @@
1/* Internal definitions for FS-Cache
2 *
3 * Copyright (C) 2004-2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12/*
13 * Lock order, in the order in which multiple locks should be obtained:
14 * - fscache_addremove_sem
15 * - cookie->lock
16 * - cookie->parent->lock
17 * - cache->object_list_lock
18 * - object->lock
19 * - object->parent->lock
20 * - fscache_thread_lock
21 *
22 */
23
24#include <linux/fscache-cache.h>
25#include <linux/sched.h>
26
27#define FSCACHE_MIN_THREADS 4
28#define FSCACHE_MAX_THREADS 32
29
30/*
31 * fsc-cache.c
32 */
33extern struct list_head fscache_cache_list;
34extern struct rw_semaphore fscache_addremove_sem;
35
36extern struct fscache_cache *fscache_select_cache_for_object(
37 struct fscache_cookie *);
38
39/*
40 * fsc-cookie.c
41 */
42extern struct kmem_cache *fscache_cookie_jar;
43
44extern void fscache_cookie_init_once(void *);
45extern void __fscache_cookie_put(struct fscache_cookie *);
46
47/*
48 * fsc-fsdef.c
49 */
50extern struct fscache_cookie fscache_fsdef_index;
51extern struct fscache_cookie_def fscache_fsdef_netfs_def;
52
53/*
54 * fsc-histogram.c
55 */
56#ifdef CONFIG_FSCACHE_HISTOGRAM
57extern atomic_t fscache_obj_instantiate_histogram[HZ];
58extern atomic_t fscache_objs_histogram[HZ];
59extern atomic_t fscache_ops_histogram[HZ];
60extern atomic_t fscache_retrieval_delay_histogram[HZ];
61extern atomic_t fscache_retrieval_histogram[HZ];
62
63static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
64{
65 unsigned long jif = jiffies - start_jif;
66 if (jif >= HZ)
67 jif = HZ - 1;
68 atomic_inc(&histogram[jif]);
69}
70
71extern const struct file_operations fscache_histogram_fops;
72
73#else
74#define fscache_hist(hist, start_jif) do {} while (0)
75#endif
76
77/*
78 * fsc-main.c
79 */
80extern unsigned fscache_defer_lookup;
81extern unsigned fscache_defer_create;
82extern unsigned fscache_debug;
83extern struct kobject *fscache_root;
84
85extern int fscache_wait_bit(void *);
86extern int fscache_wait_bit_interruptible(void *);
87
88/*
89 * fsc-object.c
90 */
91extern void fscache_withdrawing_object(struct fscache_cache *,
92 struct fscache_object *);
93extern void fscache_enqueue_object(struct fscache_object *);
94
95/*
96 * fsc-operation.c
97 */
98extern int fscache_submit_exclusive_op(struct fscache_object *,
99 struct fscache_operation *);
100extern int fscache_submit_op(struct fscache_object *,
101 struct fscache_operation *);
102extern void fscache_abort_object(struct fscache_object *);
103extern void fscache_start_operations(struct fscache_object *);
104extern void fscache_operation_gc(struct work_struct *);
105
106/*
107 * fsc-proc.c
108 */
109#ifdef CONFIG_PROC_FS
110extern int __init fscache_proc_init(void);
111extern void fscache_proc_cleanup(void);
112#else
113#define fscache_proc_init() (0)
114#define fscache_proc_cleanup() do {} while (0)
115#endif
116
117/*
118 * fsc-stats.c
119 */
120#ifdef CONFIG_FSCACHE_STATS
121extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
122extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
123
124extern atomic_t fscache_n_op_pend;
125extern atomic_t fscache_n_op_run;
126extern atomic_t fscache_n_op_enqueue;
127extern atomic_t fscache_n_op_deferred_release;
128extern atomic_t fscache_n_op_release;
129extern atomic_t fscache_n_op_gc;
130
131extern atomic_t fscache_n_attr_changed;
132extern atomic_t fscache_n_attr_changed_ok;
133extern atomic_t fscache_n_attr_changed_nobufs;
134extern atomic_t fscache_n_attr_changed_nomem;
135extern atomic_t fscache_n_attr_changed_calls;
136
137extern atomic_t fscache_n_allocs;
138extern atomic_t fscache_n_allocs_ok;
139extern atomic_t fscache_n_allocs_wait;
140extern atomic_t fscache_n_allocs_nobufs;
141extern atomic_t fscache_n_alloc_ops;
142extern atomic_t fscache_n_alloc_op_waits;
143
144extern atomic_t fscache_n_retrievals;
145extern atomic_t fscache_n_retrievals_ok;
146extern atomic_t fscache_n_retrievals_wait;
147extern atomic_t fscache_n_retrievals_nodata;
148extern atomic_t fscache_n_retrievals_nobufs;
149extern atomic_t fscache_n_retrievals_intr;
150extern atomic_t fscache_n_retrievals_nomem;
151extern atomic_t fscache_n_retrieval_ops;
152extern atomic_t fscache_n_retrieval_op_waits;
153
154extern atomic_t fscache_n_stores;
155extern atomic_t fscache_n_stores_ok;
156extern atomic_t fscache_n_stores_again;
157extern atomic_t fscache_n_stores_nobufs;
158extern atomic_t fscache_n_stores_oom;
159extern atomic_t fscache_n_store_ops;
160extern atomic_t fscache_n_store_calls;
161
162extern atomic_t fscache_n_marks;
163extern atomic_t fscache_n_uncaches;
164
165extern atomic_t fscache_n_acquires;
166extern atomic_t fscache_n_acquires_null;
167extern atomic_t fscache_n_acquires_no_cache;
168extern atomic_t fscache_n_acquires_ok;
169extern atomic_t fscache_n_acquires_nobufs;
170extern atomic_t fscache_n_acquires_oom;
171
172extern atomic_t fscache_n_updates;
173extern atomic_t fscache_n_updates_null;
174extern atomic_t fscache_n_updates_run;
175
176extern atomic_t fscache_n_relinquishes;
177extern atomic_t fscache_n_relinquishes_null;
178extern atomic_t fscache_n_relinquishes_waitcrt;
179
180extern atomic_t fscache_n_cookie_index;
181extern atomic_t fscache_n_cookie_data;
182extern atomic_t fscache_n_cookie_special;
183
184extern atomic_t fscache_n_object_alloc;
185extern atomic_t fscache_n_object_no_alloc;
186extern atomic_t fscache_n_object_lookups;
187extern atomic_t fscache_n_object_lookups_negative;
188extern atomic_t fscache_n_object_lookups_positive;
189extern atomic_t fscache_n_object_created;
190extern atomic_t fscache_n_object_avail;
191extern atomic_t fscache_n_object_dead;
192
193extern atomic_t fscache_n_checkaux_none;
194extern atomic_t fscache_n_checkaux_okay;
195extern atomic_t fscache_n_checkaux_update;
196extern atomic_t fscache_n_checkaux_obsolete;
197
198static inline void fscache_stat(atomic_t *stat)
199{
200 atomic_inc(stat);
201}
202
203extern const struct file_operations fscache_stats_fops;
204#else
205
206#define fscache_stat(stat) do {} while (0)
207#endif
208
209/*
210 * raise an event on an object
211 * - if the event is not masked for that object, then the object is
212 * queued for attention by the thread pool.
213 */
214static inline void fscache_raise_event(struct fscache_object *object,
215 unsigned event)
216{
217 if (!test_and_set_bit(event, &object->events) &&
218 test_bit(event, &object->event_mask))
219 fscache_enqueue_object(object);
220}
221
222/*
223 * drop a reference to a cookie
224 */
225static inline void fscache_cookie_put(struct fscache_cookie *cookie)
226{
227 BUG_ON(atomic_read(&cookie->usage) <= 0);
228 if (atomic_dec_and_test(&cookie->usage))
229 __fscache_cookie_put(cookie);
230}
231
232/*
233 * get an extra reference to a netfs retrieval context
234 */
235static inline
236void *fscache_get_context(struct fscache_cookie *cookie, void *context)
237{
238 if (cookie->def->get_context)
239 cookie->def->get_context(cookie->netfs_data, context);
240 return context;
241}
242
243/*
244 * release a reference to a netfs retrieval context
245 */
246static inline
247void fscache_put_context(struct fscache_cookie *cookie, void *context)
248{
249 if (cookie->def->put_context)
250 cookie->def->put_context(cookie->netfs_data, context);
251}
252
253/*****************************************************************************/
254/*
255 * debug tracing
256 */
257#define dbgprintk(FMT, ...) \
258 printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
259
260/* make sure we maintain the format strings, even when debugging is disabled */
261static inline __attribute__((format(printf, 1, 2)))
262void _dbprintk(const char *fmt, ...)
263{
264}
265
266#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
267#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
268#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
269
270#define kjournal(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
271
272#ifdef __KDEBUG
273#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
274#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
275#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
276
277#elif defined(CONFIG_FSCACHE_DEBUG)
278#define _enter(FMT, ...) \
279do { \
280 if (__do_kdebug(ENTER)) \
281 kenter(FMT, ##__VA_ARGS__); \
282} while (0)
283
284#define _leave(FMT, ...) \
285do { \
286 if (__do_kdebug(LEAVE)) \
287 kleave(FMT, ##__VA_ARGS__); \
288} while (0)
289
290#define _debug(FMT, ...) \
291do { \
292 if (__do_kdebug(DEBUG)) \
293 kdebug(FMT, ##__VA_ARGS__); \
294} while (0)
295
296#else
297#define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
298#define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
299#define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
300#endif
301
302/*
303 * determine whether a particular optional debugging point should be logged
304 * - we need to go through three steps to persuade cpp to correctly join the
305 * shorthand in FSCACHE_DEBUG_LEVEL with its prefix
306 */
307#define ____do_kdebug(LEVEL, POINT) \
308 unlikely((fscache_debug & \
309 (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
310#define ___do_kdebug(LEVEL, POINT) \
311 ____do_kdebug(LEVEL, POINT)
312#define __do_kdebug(POINT) \
313 ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
314
315#define FSCACHE_DEBUG_CACHE 0
316#define FSCACHE_DEBUG_COOKIE 1
317#define FSCACHE_DEBUG_PAGE 2
318#define FSCACHE_DEBUG_OPERATION 3
319
320#define FSCACHE_POINT_ENTER 1
321#define FSCACHE_POINT_LEAVE 2
322#define FSCACHE_POINT_DEBUG 4
323
324#ifndef FSCACHE_DEBUG_LEVEL
325#define FSCACHE_DEBUG_LEVEL CACHE
326#endif
327
328/*
329 * assertions
330 */
331#if 1 /* defined(__KDEBUGALL) */
332
333#define ASSERT(X) \
334do { \
335 if (unlikely(!(X))) { \
336 printk(KERN_ERR "\n"); \
337 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
338 BUG(); \
339 } \
340} while (0)
341
342#define ASSERTCMP(X, OP, Y) \
343do { \
344 if (unlikely(!((X) OP (Y)))) { \
345 printk(KERN_ERR "\n"); \
346 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
347 printk(KERN_ERR "%lx " #OP " %lx is false\n", \
348 (unsigned long)(X), (unsigned long)(Y)); \
349 BUG(); \
350 } \
351} while (0)
352
353#define ASSERTIF(C, X) \
354do { \
355 if (unlikely((C) && !(X))) { \
356 printk(KERN_ERR "\n"); \
357 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
358 BUG(); \
359 } \
360} while (0)
361
362#define ASSERTIFCMP(C, X, OP, Y) \
363do { \
364 if (unlikely((C) && !((X) OP (Y)))) { \
365 printk(KERN_ERR "\n"); \
366 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
367 printk(KERN_ERR "%lx " #OP " %lx is false\n", \
368 (unsigned long)(X), (unsigned long)(Y)); \
369 BUG(); \
370 } \
371} while (0)
372
373#else
374
375#define ASSERT(X) do {} while (0)
376#define ASSERTCMP(X, OP, Y) do {} while (0)
377#define ASSERTIF(C, X) do {} while (0)
378#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
379
380#endif /* assert or not */
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
new file mode 100644
index 000000000000..4de41b597499
--- /dev/null
+++ b/fs/fscache/main.c
@@ -0,0 +1,124 @@
1/* General filesystem local caching manager
2 *
3 * Copyright (C) 2004-2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL CACHE
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/sched.h>
16#include <linux/completion.h>
17#include <linux/slab.h>
18#include "internal.h"
19
20MODULE_DESCRIPTION("FS Cache Manager");
21MODULE_AUTHOR("Red Hat, Inc.");
22MODULE_LICENSE("GPL");
23
24unsigned fscache_defer_lookup = 1;
25module_param_named(defer_lookup, fscache_defer_lookup, uint,
26 S_IWUSR | S_IRUGO);
27MODULE_PARM_DESC(fscache_defer_lookup,
28 "Defer cookie lookup to background thread");
29
30unsigned fscache_defer_create = 1;
31module_param_named(defer_create, fscache_defer_create, uint,
32 S_IWUSR | S_IRUGO);
33MODULE_PARM_DESC(fscache_defer_create,
34 "Defer cookie creation to background thread");
35
36unsigned fscache_debug;
37module_param_named(debug, fscache_debug, uint,
38 S_IWUSR | S_IRUGO);
39MODULE_PARM_DESC(fscache_debug,
40 "FS-Cache debugging mask");
41
42struct kobject *fscache_root;
43
44/*
45 * initialise the fs caching module
46 */
47static int __init fscache_init(void)
48{
49 int ret;
50
51 ret = slow_work_register_user();
52 if (ret < 0)
53 goto error_slow_work;
54
55 ret = fscache_proc_init();
56 if (ret < 0)
57 goto error_proc;
58
59 fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
60 sizeof(struct fscache_cookie),
61 0,
62 0,
63 fscache_cookie_init_once);
64 if (!fscache_cookie_jar) {
65 printk(KERN_NOTICE
66 "FS-Cache: Failed to allocate a cookie jar\n");
67 ret = -ENOMEM;
68 goto error_cookie_jar;
69 }
70
71 fscache_root = kobject_create_and_add("fscache", kernel_kobj);
72 if (!fscache_root)
73 goto error_kobj;
74
75 printk(KERN_NOTICE "FS-Cache: Loaded\n");
76 return 0;
77
78error_kobj:
79 kmem_cache_destroy(fscache_cookie_jar);
80error_cookie_jar:
81 fscache_proc_cleanup();
82error_proc:
83 slow_work_unregister_user();
84error_slow_work:
85 return ret;
86}
87
88fs_initcall(fscache_init);
89
90/*
91 * clean up on module removal
92 */
93static void __exit fscache_exit(void)
94{
95 _enter("");
96
97 kobject_put(fscache_root);
98 kmem_cache_destroy(fscache_cookie_jar);
99 fscache_proc_cleanup();
100 slow_work_unregister_user();
101 printk(KERN_NOTICE "FS-Cache: Unloaded\n");
102}
103
104module_exit(fscache_exit);
105
106/*
107 * wait_on_bit() sleep function for uninterruptible waiting
108 */
109int fscache_wait_bit(void *flags)
110{
111 schedule();
112 return 0;
113}
114EXPORT_SYMBOL(fscache_wait_bit);
115
116/*
117 * wait_on_bit() sleep function for interruptible waiting
118 */
119int fscache_wait_bit_interruptible(void *flags)
120{
121 schedule();
122 return signal_pending(current);
123}
124EXPORT_SYMBOL(fscache_wait_bit_interruptible);
diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
new file mode 100644
index 000000000000..e028b8eb1c40
--- /dev/null
+++ b/fs/fscache/netfs.c
@@ -0,0 +1,103 @@
1/* FS-Cache netfs (client) registration
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#define FSCACHE_DEBUG_LEVEL COOKIE
13#include <linux/module.h>
14#include <linux/slab.h>
15#include "internal.h"
16
17static LIST_HEAD(fscache_netfs_list);
18
19/*
20 * register a network filesystem for caching
21 */
22int __fscache_register_netfs(struct fscache_netfs *netfs)
23{
24 struct fscache_netfs *ptr;
25 int ret;
26
27 _enter("{%s}", netfs->name);
28
29 INIT_LIST_HEAD(&netfs->link);
30
31 /* allocate a cookie for the primary index */
32 netfs->primary_index =
33 kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
34
35 if (!netfs->primary_index) {
36 _leave(" = -ENOMEM");
37 return -ENOMEM;
38 }
39
40 /* initialise the primary index cookie */
41 atomic_set(&netfs->primary_index->usage, 1);
42 atomic_set(&netfs->primary_index->n_children, 0);
43
44 netfs->primary_index->def = &fscache_fsdef_netfs_def;
45 netfs->primary_index->parent = &fscache_fsdef_index;
46 netfs->primary_index->netfs_data = netfs;
47
48 atomic_inc(&netfs->primary_index->parent->usage);
49 atomic_inc(&netfs->primary_index->parent->n_children);
50
51 spin_lock_init(&netfs->primary_index->lock);
52 INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
53
54 /* check the netfs type is not already present */
55 down_write(&fscache_addremove_sem);
56
57 ret = -EEXIST;
58 list_for_each_entry(ptr, &fscache_netfs_list, link) {
59 if (strcmp(ptr->name, netfs->name) == 0)
60 goto already_registered;
61 }
62
63 list_add(&netfs->link, &fscache_netfs_list);
64 ret = 0;
65
66 printk(KERN_NOTICE "FS-Cache: Netfs '%s' registered for caching\n",
67 netfs->name);
68
69already_registered:
70 up_write(&fscache_addremove_sem);
71
72 if (ret < 0) {
73 netfs->primary_index->parent = NULL;
74 __fscache_cookie_put(netfs->primary_index);
75 netfs->primary_index = NULL;
76 }
77
78 _leave(" = %d", ret);
79 return ret;
80}
81EXPORT_SYMBOL(__fscache_register_netfs);
82
83/*
84 * unregister a network filesystem from the cache
85 * - all cookies must have been released first
86 */
87void __fscache_unregister_netfs(struct fscache_netfs *netfs)
88{
89 _enter("{%s.%u}", netfs->name, netfs->version);
90
91 down_write(&fscache_addremove_sem);
92
93 list_del(&netfs->link);
94 fscache_relinquish_cookie(netfs->primary_index, 0);
95
96 up_write(&fscache_addremove_sem);
97
98 printk(KERN_NOTICE "FS-Cache: Netfs '%s' unregistered from caching\n",
99 netfs->name);
100
101 _leave("");
102}
103EXPORT_SYMBOL(__fscache_unregister_netfs);
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
new file mode 100644
index 000000000000..392a41b1b79d
--- /dev/null
+++ b/fs/fscache/object.c
@@ -0,0 +1,810 @@
1/* FS-Cache object state machine handler
2 *
3 * Copyright (C) 2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * See Documentation/filesystems/caching/object.txt for a description of the
12 * object state machine and the in-kernel representations.
13 */
14
15#define FSCACHE_DEBUG_LEVEL COOKIE
16#include <linux/module.h>
17#include "internal.h"
18
19const char *fscache_object_states[] = {
20 [FSCACHE_OBJECT_INIT] = "OBJECT_INIT",
21 [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP",
22 [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING",
23 [FSCACHE_OBJECT_AVAILABLE] = "OBJECT_AVAILABLE",
24 [FSCACHE_OBJECT_ACTIVE] = "OBJECT_ACTIVE",
25 [FSCACHE_OBJECT_UPDATING] = "OBJECT_UPDATING",
26 [FSCACHE_OBJECT_DYING] = "OBJECT_DYING",
27 [FSCACHE_OBJECT_LC_DYING] = "OBJECT_LC_DYING",
28 [FSCACHE_OBJECT_ABORT_INIT] = "OBJECT_ABORT_INIT",
29 [FSCACHE_OBJECT_RELEASING] = "OBJECT_RELEASING",
30 [FSCACHE_OBJECT_RECYCLING] = "OBJECT_RECYCLING",
31 [FSCACHE_OBJECT_WITHDRAWING] = "OBJECT_WITHDRAWING",
32 [FSCACHE_OBJECT_DEAD] = "OBJECT_DEAD",
33};
34EXPORT_SYMBOL(fscache_object_states);
35
36static void fscache_object_slow_work_put_ref(struct slow_work *);
37static int fscache_object_slow_work_get_ref(struct slow_work *);
38static void fscache_object_slow_work_execute(struct slow_work *);
39static void fscache_initialise_object(struct fscache_object *);
40static void fscache_lookup_object(struct fscache_object *);
41static void fscache_object_available(struct fscache_object *);
42static void fscache_release_object(struct fscache_object *);
43static void fscache_withdraw_object(struct fscache_object *);
44static void fscache_enqueue_dependents(struct fscache_object *);
45static void fscache_dequeue_object(struct fscache_object *);
46
47const struct slow_work_ops fscache_object_slow_work_ops = {
48 .get_ref = fscache_object_slow_work_get_ref,
49 .put_ref = fscache_object_slow_work_put_ref,
50 .execute = fscache_object_slow_work_execute,
51};
52EXPORT_SYMBOL(fscache_object_slow_work_ops);
53
54/*
55 * we need to notify the parent when an op completes that we had outstanding
56 * upon it
57 */
58static inline void fscache_done_parent_op(struct fscache_object *object)
59{
60 struct fscache_object *parent = object->parent;
61
62 _enter("OBJ%x {OBJ%x,%x}",
63 object->debug_id, parent->debug_id, parent->n_ops);
64
65 spin_lock_nested(&parent->lock, 1);
66 parent->n_ops--;
67 parent->n_obj_ops--;
68 if (parent->n_ops == 0)
69 fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
70 spin_unlock(&parent->lock);
71}
72
73/*
74 * process events that have been sent to an object's state machine
75 * - initiates parent lookup
76 * - does object lookup
77 * - does object creation
78 * - does object recycling and retirement
79 * - does object withdrawal
80 */
81static void fscache_object_state_machine(struct fscache_object *object)
82{
83 enum fscache_object_state new_state;
84
85 ASSERT(object != NULL);
86
87 _enter("{OBJ%x,%s,%lx}",
88 object->debug_id, fscache_object_states[object->state],
89 object->events);
90
91 switch (object->state) {
92 /* wait for the parent object to become ready */
93 case FSCACHE_OBJECT_INIT:
94 object->event_mask =
95 ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED);
96 fscache_initialise_object(object);
97 goto done;
98
99 /* look up the object metadata on disk */
100 case FSCACHE_OBJECT_LOOKING_UP:
101 fscache_lookup_object(object);
102 goto lookup_transit;
103
104 /* create the object metadata on disk */
105 case FSCACHE_OBJECT_CREATING:
106 fscache_lookup_object(object);
107 goto lookup_transit;
108
109 /* handle an object becoming available; start pending
110 * operations and queue dependent operations for processing */
111 case FSCACHE_OBJECT_AVAILABLE:
112 fscache_object_available(object);
113 goto active_transit;
114
115 /* normal running state */
116 case FSCACHE_OBJECT_ACTIVE:
117 goto active_transit;
118
119 /* update the object metadata on disk */
120 case FSCACHE_OBJECT_UPDATING:
121 clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events);
122 fscache_stat(&fscache_n_updates_run);
123 object->cache->ops->update_object(object);
124 goto active_transit;
125
126 /* handle an object dying during lookup or creation */
127 case FSCACHE_OBJECT_LC_DYING:
128 object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
129 object->cache->ops->lookup_complete(object);
130
131 spin_lock(&object->lock);
132 object->state = FSCACHE_OBJECT_DYING;
133 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
134 &object->cookie->flags))
135 wake_up_bit(&object->cookie->flags,
136 FSCACHE_COOKIE_CREATING);
137 spin_unlock(&object->lock);
138
139 fscache_done_parent_op(object);
140
141 /* wait for completion of all active operations on this object
142 * and the death of all child objects of this object */
143 case FSCACHE_OBJECT_DYING:
144 dying:
145 clear_bit(FSCACHE_OBJECT_EV_CLEARED, &object->events);
146 spin_lock(&object->lock);
147 _debug("dying OBJ%x {%d,%d}",
148 object->debug_id, object->n_ops, object->n_children);
149 if (object->n_ops == 0 && object->n_children == 0) {
150 object->event_mask &=
151 ~(1 << FSCACHE_OBJECT_EV_CLEARED);
152 object->event_mask |=
153 (1 << FSCACHE_OBJECT_EV_WITHDRAW) |
154 (1 << FSCACHE_OBJECT_EV_RETIRE) |
155 (1 << FSCACHE_OBJECT_EV_RELEASE) |
156 (1 << FSCACHE_OBJECT_EV_ERROR);
157 } else {
158 object->event_mask &=
159 ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
160 (1 << FSCACHE_OBJECT_EV_RETIRE) |
161 (1 << FSCACHE_OBJECT_EV_RELEASE) |
162 (1 << FSCACHE_OBJECT_EV_ERROR));
163 object->event_mask |=
164 1 << FSCACHE_OBJECT_EV_CLEARED;
165 }
166 spin_unlock(&object->lock);
167 fscache_enqueue_dependents(object);
168 goto terminal_transit;
169
170 /* handle an abort during initialisation */
171 case FSCACHE_OBJECT_ABORT_INIT:
172 _debug("handle abort init %lx", object->events);
173 object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
174
175 spin_lock(&object->lock);
176 fscache_dequeue_object(object);
177
178 object->state = FSCACHE_OBJECT_DYING;
179 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
180 &object->cookie->flags))
181 wake_up_bit(&object->cookie->flags,
182 FSCACHE_COOKIE_CREATING);
183 spin_unlock(&object->lock);
184 goto dying;
185
186 /* handle the netfs releasing an object and possibly marking it
187 * obsolete too */
188 case FSCACHE_OBJECT_RELEASING:
189 case FSCACHE_OBJECT_RECYCLING:
190 object->event_mask &=
191 ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
192 (1 << FSCACHE_OBJECT_EV_RETIRE) |
193 (1 << FSCACHE_OBJECT_EV_RELEASE) |
194 (1 << FSCACHE_OBJECT_EV_ERROR));
195 fscache_release_object(object);
196 spin_lock(&object->lock);
197 object->state = FSCACHE_OBJECT_DEAD;
198 spin_unlock(&object->lock);
199 fscache_stat(&fscache_n_object_dead);
200 goto terminal_transit;
201
202 /* handle the parent cache of this object being withdrawn from
203 * active service */
204 case FSCACHE_OBJECT_WITHDRAWING:
205 object->event_mask &=
206 ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
207 (1 << FSCACHE_OBJECT_EV_RETIRE) |
208 (1 << FSCACHE_OBJECT_EV_RELEASE) |
209 (1 << FSCACHE_OBJECT_EV_ERROR));
210 fscache_withdraw_object(object);
211 spin_lock(&object->lock);
212 object->state = FSCACHE_OBJECT_DEAD;
213 spin_unlock(&object->lock);
214 fscache_stat(&fscache_n_object_dead);
215 goto terminal_transit;
216
217 /* complain about the object being woken up once it is
218 * deceased */
219 case FSCACHE_OBJECT_DEAD:
220 printk(KERN_ERR "FS-Cache:"
221 " Unexpected event in dead state %lx\n",
222 object->events & object->event_mask);
223 BUG();
224
225 default:
226 printk(KERN_ERR "FS-Cache: Unknown object state %u\n",
227 object->state);
228 BUG();
229 }
230
231 /* determine the transition from a lookup state */
232lookup_transit:
233 switch (fls(object->events & object->event_mask) - 1) {
234 case FSCACHE_OBJECT_EV_WITHDRAW:
235 case FSCACHE_OBJECT_EV_RETIRE:
236 case FSCACHE_OBJECT_EV_RELEASE:
237 case FSCACHE_OBJECT_EV_ERROR:
238 new_state = FSCACHE_OBJECT_LC_DYING;
239 goto change_state;
240 case FSCACHE_OBJECT_EV_REQUEUE:
241 goto done;
242 case -1:
243 goto done; /* sleep until event */
244 default:
245 goto unsupported_event;
246 }
247
248 /* determine the transition from an active state */
249active_transit:
250 switch (fls(object->events & object->event_mask) - 1) {
251 case FSCACHE_OBJECT_EV_WITHDRAW:
252 case FSCACHE_OBJECT_EV_RETIRE:
253 case FSCACHE_OBJECT_EV_RELEASE:
254 case FSCACHE_OBJECT_EV_ERROR:
255 new_state = FSCACHE_OBJECT_DYING;
256 goto change_state;
257 case FSCACHE_OBJECT_EV_UPDATE:
258 new_state = FSCACHE_OBJECT_UPDATING;
259 goto change_state;
260 case -1:
261 new_state = FSCACHE_OBJECT_ACTIVE;
262 goto change_state; /* sleep until event */
263 default:
264 goto unsupported_event;
265 }
266
267 /* determine the transition from a terminal state */
268terminal_transit:
269 switch (fls(object->events & object->event_mask) - 1) {
270 case FSCACHE_OBJECT_EV_WITHDRAW:
271 new_state = FSCACHE_OBJECT_WITHDRAWING;
272 goto change_state;
273 case FSCACHE_OBJECT_EV_RETIRE:
274 new_state = FSCACHE_OBJECT_RECYCLING;
275 goto change_state;
276 case FSCACHE_OBJECT_EV_RELEASE:
277 new_state = FSCACHE_OBJECT_RELEASING;
278 goto change_state;
279 case FSCACHE_OBJECT_EV_ERROR:
280 new_state = FSCACHE_OBJECT_WITHDRAWING;
281 goto change_state;
282 case FSCACHE_OBJECT_EV_CLEARED:
283 new_state = FSCACHE_OBJECT_DYING;
284 goto change_state;
285 case -1:
286 goto done; /* sleep until event */
287 default:
288 goto unsupported_event;
289 }
290
291change_state:
292 spin_lock(&object->lock);
293 object->state = new_state;
294 spin_unlock(&object->lock);
295
296done:
297 _leave(" [->%s]", fscache_object_states[object->state]);
298 return;
299
300unsupported_event:
301 printk(KERN_ERR "FS-Cache:"
302 " Unsupported event %lx [mask %lx] in state %s\n",
303 object->events, object->event_mask,
304 fscache_object_states[object->state]);
305 BUG();
306}
307
308/*
309 * execute an object
310 */
311static void fscache_object_slow_work_execute(struct slow_work *work)
312{
313 struct fscache_object *object =
314 container_of(work, struct fscache_object, work);
315 unsigned long start;
316
317 _enter("{OBJ%x}", object->debug_id);
318
319 clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
320
321 start = jiffies;
322 fscache_object_state_machine(object);
323 fscache_hist(fscache_objs_histogram, start);
324 if (object->events & object->event_mask)
325 fscache_enqueue_object(object);
326}
327
328/*
329 * initialise an object
330 * - check the specified object's parent to see if we can make use of it
331 * immediately to do a creation
332 * - we may need to start the process of creating a parent and we need to wait
333 * for the parent's lookup and creation to complete if it's not there yet
334 * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
335 * leaf-most cookies of the object and all its children
336 */
337static void fscache_initialise_object(struct fscache_object *object)
338{
339 struct fscache_object *parent;
340
341 _enter("");
342 ASSERT(object->cookie != NULL);
343 ASSERT(object->cookie->parent != NULL);
344 ASSERT(list_empty(&object->work.link));
345
346 if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
347 (1 << FSCACHE_OBJECT_EV_RELEASE) |
348 (1 << FSCACHE_OBJECT_EV_RETIRE) |
349 (1 << FSCACHE_OBJECT_EV_WITHDRAW))) {
350 _debug("abort init %lx", object->events);
351 spin_lock(&object->lock);
352 object->state = FSCACHE_OBJECT_ABORT_INIT;
353 spin_unlock(&object->lock);
354 return;
355 }
356
357 spin_lock(&object->cookie->lock);
358 spin_lock_nested(&object->cookie->parent->lock, 1);
359
360 parent = object->parent;
361 if (!parent) {
362 _debug("no parent");
363 set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
364 } else {
365 spin_lock(&object->lock);
366 spin_lock_nested(&parent->lock, 1);
367 _debug("parent %s", fscache_object_states[parent->state]);
368
369 if (parent->state >= FSCACHE_OBJECT_DYING) {
370 _debug("bad parent");
371 set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
372 } else if (parent->state < FSCACHE_OBJECT_AVAILABLE) {
373 _debug("wait");
374
375 /* we may get woken up in this state by child objects
376 * binding on to us, so we need to make sure we don't
377 * add ourself to the list multiple times */
378 if (list_empty(&object->dep_link)) {
379 object->cache->ops->grab_object(object);
380 list_add(&object->dep_link,
381 &parent->dependents);
382
383 /* fscache_acquire_non_index_cookie() uses this
384 * to wake the chain up */
385 if (parent->state == FSCACHE_OBJECT_INIT)
386 fscache_enqueue_object(parent);
387 }
388 } else {
389 _debug("go");
390 parent->n_ops++;
391 parent->n_obj_ops++;
392 object->lookup_jif = jiffies;
393 object->state = FSCACHE_OBJECT_LOOKING_UP;
394 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
395 }
396
397 spin_unlock(&parent->lock);
398 spin_unlock(&object->lock);
399 }
400
401 spin_unlock(&object->cookie->parent->lock);
402 spin_unlock(&object->cookie->lock);
403 _leave("");
404}
405
406/*
407 * look an object up in the cache from which it was allocated
408 * - we hold an "access lock" on the parent object, so the parent object cannot
409 * be withdrawn by either party till we've finished
410 * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
411 * leaf-most cookies of the object and all its children
412 */
413static void fscache_lookup_object(struct fscache_object *object)
414{
415 struct fscache_cookie *cookie = object->cookie;
416 struct fscache_object *parent;
417
418 _enter("");
419
420 parent = object->parent;
421 ASSERT(parent != NULL);
422 ASSERTCMP(parent->n_ops, >, 0);
423 ASSERTCMP(parent->n_obj_ops, >, 0);
424
425 /* make sure the parent is still available */
426 ASSERTCMP(parent->state, >=, FSCACHE_OBJECT_AVAILABLE);
427
428 if (parent->state >= FSCACHE_OBJECT_DYING ||
429 test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
430 _debug("unavailable");
431 set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
432 _leave("");
433 return;
434 }
435
436 _debug("LOOKUP \"%s/%s\" in \"%s\"",
437 parent->cookie->def->name, cookie->def->name,
438 object->cache->tag->name);
439
440 fscache_stat(&fscache_n_object_lookups);
441 object->cache->ops->lookup_object(object);
442
443 if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events))
444 set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
445
446 _leave("");
447}
448
449/**
450 * fscache_object_lookup_negative - Note negative cookie lookup
451 * @object: Object pointing to cookie to mark
452 *
453 * Note negative lookup, permitting those waiting to read data from an already
454 * existing backing object to continue as there's no data for them to read.
455 */
456void fscache_object_lookup_negative(struct fscache_object *object)
457{
458 struct fscache_cookie *cookie = object->cookie;
459
460 _enter("{OBJ%x,%s}",
461 object->debug_id, fscache_object_states[object->state]);
462
463 spin_lock(&object->lock);
464 if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
465 fscache_stat(&fscache_n_object_lookups_negative);
466
467 /* transit here to allow write requests to begin stacking up
468 * and read requests to begin returning ENODATA */
469 object->state = FSCACHE_OBJECT_CREATING;
470 spin_unlock(&object->lock);
471
472 set_bit(FSCACHE_COOKIE_PENDING_FILL, &cookie->flags);
473 set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
474
475 _debug("wake up lookup %p", &cookie->flags);
476 smp_mb__before_clear_bit();
477 clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
478 smp_mb__after_clear_bit();
479 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
480 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
481 } else {
482 ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
483 spin_unlock(&object->lock);
484 }
485
486 _leave("");
487}
488EXPORT_SYMBOL(fscache_object_lookup_negative);
489
490/**
491 * fscache_obtained_object - Note successful object lookup or creation
492 * @object: Object pointing to cookie to mark
493 *
494 * Note successful lookup and/or creation, permitting those waiting to write
495 * data to a backing object to continue.
496 *
497 * Note that after calling this, an object's cookie may be relinquished by the
498 * netfs, and so must be accessed with object lock held.
499 */
500void fscache_obtained_object(struct fscache_object *object)
501{
502 struct fscache_cookie *cookie = object->cookie;
503
504 _enter("{OBJ%x,%s}",
505 object->debug_id, fscache_object_states[object->state]);
506
507 /* if we were still looking up, then we must have a positive lookup
508 * result, in which case there may be data available */
509 spin_lock(&object->lock);
510 if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
511 fscache_stat(&fscache_n_object_lookups_positive);
512
513 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
514
515 object->state = FSCACHE_OBJECT_AVAILABLE;
516 spin_unlock(&object->lock);
517
518 smp_mb__before_clear_bit();
519 clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
520 smp_mb__after_clear_bit();
521 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
522 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
523 } else {
524 ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
525 fscache_stat(&fscache_n_object_created);
526
527 object->state = FSCACHE_OBJECT_AVAILABLE;
528 spin_unlock(&object->lock);
529 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
530 smp_wmb();
531 }
532
533 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &cookie->flags))
534 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING);
535
536 _leave("");
537}
538EXPORT_SYMBOL(fscache_obtained_object);
539
540/*
541 * handle an object that has just become available
542 */
543static void fscache_object_available(struct fscache_object *object)
544{
545 _enter("{OBJ%x}", object->debug_id);
546
547 spin_lock(&object->lock);
548
549 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
550 wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING);
551
552 fscache_done_parent_op(object);
553 if (object->n_in_progress == 0) {
554 if (object->n_ops > 0) {
555 ASSERTCMP(object->n_ops, >=, object->n_obj_ops);
556 ASSERTIF(object->n_ops > object->n_obj_ops,
557 !list_empty(&object->pending_ops));
558 fscache_start_operations(object);
559 } else {
560 ASSERT(list_empty(&object->pending_ops));
561 }
562 }
563 spin_unlock(&object->lock);
564
565 object->cache->ops->lookup_complete(object);
566 fscache_enqueue_dependents(object);
567
568 fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif);
569 fscache_stat(&fscache_n_object_avail);
570
571 _leave("");
572}
573
574/*
575 * drop an object's attachments
576 */
577static void fscache_drop_object(struct fscache_object *object)
578{
579 struct fscache_object *parent = object->parent;
580 struct fscache_cache *cache = object->cache;
581
582 _enter("{OBJ%x,%d}", object->debug_id, object->n_children);
583
584 spin_lock(&cache->object_list_lock);
585 list_del_init(&object->cache_link);
586 spin_unlock(&cache->object_list_lock);
587
588 cache->ops->drop_object(object);
589
590 if (parent) {
591 _debug("release parent OBJ%x {%d}",
592 parent->debug_id, parent->n_children);
593
594 spin_lock(&parent->lock);
595 parent->n_children--;
596 if (parent->n_children == 0)
597 fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
598 spin_unlock(&parent->lock);
599 object->parent = NULL;
600 }
601
602 /* this just shifts the object release to the slow work processor */
603 object->cache->ops->put_object(object);
604
605 _leave("");
606}
607
608/*
609 * release or recycle an object that the netfs has discarded
610 */
611static void fscache_release_object(struct fscache_object *object)
612{
613 _enter("");
614
615 fscache_drop_object(object);
616}
617
618/*
619 * withdraw an object from active service
620 */
621static void fscache_withdraw_object(struct fscache_object *object)
622{
623 struct fscache_cookie *cookie;
624 bool detached;
625
626 _enter("");
627
628 spin_lock(&object->lock);
629 cookie = object->cookie;
630 if (cookie) {
631 /* need to get the cookie lock before the object lock, starting
632 * from the object pointer */
633 atomic_inc(&cookie->usage);
634 spin_unlock(&object->lock);
635
636 detached = false;
637 spin_lock(&cookie->lock);
638 spin_lock(&object->lock);
639
640 if (object->cookie == cookie) {
641 hlist_del_init(&object->cookie_link);
642 object->cookie = NULL;
643 detached = true;
644 }
645 spin_unlock(&cookie->lock);
646 fscache_cookie_put(cookie);
647 if (detached)
648 fscache_cookie_put(cookie);
649 }
650
651 spin_unlock(&object->lock);
652
653 fscache_drop_object(object);
654}
655
656/*
657 * withdraw an object from active service at the behest of the cache
658 * - need break the links to a cached object cookie
659 * - called under two situations:
660 * (1) recycler decides to reclaim an in-use object
661 * (2) a cache is unmounted
662 * - have to take care as the cookie can be being relinquished by the netfs
663 * simultaneously
664 * - the object is pinned by the caller holding a refcount on it
665 */
666void fscache_withdrawing_object(struct fscache_cache *cache,
667 struct fscache_object *object)
668{
669 bool enqueue = false;
670
671 _enter(",OBJ%x", object->debug_id);
672
673 spin_lock(&object->lock);
674 if (object->state < FSCACHE_OBJECT_WITHDRAWING) {
675 object->state = FSCACHE_OBJECT_WITHDRAWING;
676 enqueue = true;
677 }
678 spin_unlock(&object->lock);
679
680 if (enqueue)
681 fscache_enqueue_object(object);
682
683 _leave("");
684}
685
686/*
687 * allow the slow work item processor to get a ref on an object
688 */
689static int fscache_object_slow_work_get_ref(struct slow_work *work)
690{
691 struct fscache_object *object =
692 container_of(work, struct fscache_object, work);
693
694 return object->cache->ops->grab_object(object) ? 0 : -EAGAIN;
695}
696
697/*
698 * allow the slow work item processor to discard a ref on a work item
699 */
700static void fscache_object_slow_work_put_ref(struct slow_work *work)
701{
702 struct fscache_object *object =
703 container_of(work, struct fscache_object, work);
704
705 return object->cache->ops->put_object(object);
706}
707
708/*
709 * enqueue an object for metadata-type processing
710 */
711void fscache_enqueue_object(struct fscache_object *object)
712{
713 _enter("{OBJ%x}", object->debug_id);
714
715 slow_work_enqueue(&object->work);
716}
717
718/*
719 * enqueue the dependents of an object for metadata-type processing
720 * - the caller must hold the object's lock
721 * - this may cause an already locked object to wind up being processed again
722 */
723static void fscache_enqueue_dependents(struct fscache_object *object)
724{
725 struct fscache_object *dep;
726
727 _enter("{OBJ%x}", object->debug_id);
728
729 if (list_empty(&object->dependents))
730 return;
731
732 spin_lock(&object->lock);
733
734 while (!list_empty(&object->dependents)) {
735 dep = list_entry(object->dependents.next,
736 struct fscache_object, dep_link);
737 list_del_init(&dep->dep_link);
738
739
740 /* sort onto appropriate lists */
741 fscache_enqueue_object(dep);
742 dep->cache->ops->put_object(dep);
743
744 if (!list_empty(&object->dependents))
745 cond_resched_lock(&object->lock);
746 }
747
748 spin_unlock(&object->lock);
749}
750
751/*
752 * remove an object from whatever queue it's waiting on
753 * - the caller must hold object->lock
754 */
755void fscache_dequeue_object(struct fscache_object *object)
756{
757 _enter("{OBJ%x}", object->debug_id);
758
759 if (!list_empty(&object->dep_link)) {
760 spin_lock(&object->parent->lock);
761 list_del_init(&object->dep_link);
762 spin_unlock(&object->parent->lock);
763 }
764
765 _leave("");
766}
767
768/**
769 * fscache_check_aux - Ask the netfs whether an object on disk is still valid
770 * @object: The object to ask about
771 * @data: The auxiliary data for the object
772 * @datalen: The size of the auxiliary data
773 *
774 * This function consults the netfs about the coherency state of an object
775 */
776enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
777 const void *data, uint16_t datalen)
778{
779 enum fscache_checkaux result;
780
781 if (!object->cookie->def->check_aux) {
782 fscache_stat(&fscache_n_checkaux_none);
783 return FSCACHE_CHECKAUX_OKAY;
784 }
785
786 result = object->cookie->def->check_aux(object->cookie->netfs_data,
787 data, datalen);
788 switch (result) {
789 /* entry okay as is */
790 case FSCACHE_CHECKAUX_OKAY:
791 fscache_stat(&fscache_n_checkaux_okay);
792 break;
793
794 /* entry requires update */
795 case FSCACHE_CHECKAUX_NEEDS_UPDATE:
796 fscache_stat(&fscache_n_checkaux_update);
797 break;
798
799 /* entry requires deletion */
800 case FSCACHE_CHECKAUX_OBSOLETE:
801 fscache_stat(&fscache_n_checkaux_obsolete);
802 break;
803
804 default:
805 BUG();
806 }
807
808 return result;
809}
810EXPORT_SYMBOL(fscache_check_aux);
diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
new file mode 100644
index 000000000000..e7f8d53b8b6b
--- /dev/null
+++ b/fs/fscache/operation.c
@@ -0,0 +1,459 @@
1/* FS-Cache worker operation management routines
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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * See Documentation/filesystems/caching/operations.txt
12 */
13
14#define FSCACHE_DEBUG_LEVEL OPERATION
15#include <linux/module.h>
16#include "internal.h"
17
18atomic_t fscache_op_debug_id;
19EXPORT_SYMBOL(fscache_op_debug_id);
20
21/**
22 * fscache_enqueue_operation - Enqueue an operation for processing
23 * @op: The operation to enqueue
24 *
25 * Enqueue an operation for processing by the FS-Cache thread pool.
26 *
27 * This will get its own ref on the object.
28 */
29void fscache_enqueue_operation(struct fscache_operation *op)
30{
31 _enter("{OBJ%x OP%x,%u}",
32 op->object->debug_id, op->debug_id, atomic_read(&op->usage));
33
34 ASSERT(op->processor != NULL);
35 ASSERTCMP(op->object->state, >=, FSCACHE_OBJECT_AVAILABLE);
36 ASSERTCMP(atomic_read(&op->usage), >, 0);
37
38 if (list_empty(&op->pend_link)) {
39 switch (op->flags & FSCACHE_OP_TYPE) {
40 case FSCACHE_OP_FAST:
41 _debug("queue fast");
42 atomic_inc(&op->usage);
43 if (!schedule_work(&op->fast_work))
44 fscache_put_operation(op);
45 break;
46 case FSCACHE_OP_SLOW:
47 _debug("queue slow");
48 slow_work_enqueue(&op->slow_work);
49 break;
50 case FSCACHE_OP_MYTHREAD:
51 _debug("queue for caller's attention");
52 break;
53 default:
54 printk(KERN_ERR "FS-Cache: Unexpected op type %lx",
55 op->flags);
56 BUG();
57 break;
58 }
59 fscache_stat(&fscache_n_op_enqueue);
60 }
61}
62EXPORT_SYMBOL(fscache_enqueue_operation);
63
64/*
65 * start an op running
66 */
67static void fscache_run_op(struct fscache_object *object,
68 struct fscache_operation *op)
69{
70 object->n_in_progress++;
71 if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
72 wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
73 if (op->processor)
74 fscache_enqueue_operation(op);
75 fscache_stat(&fscache_n_op_run);
76}
77
78/*
79 * submit an exclusive operation for an object
80 * - other ops are excluded from running simultaneously with this one
81 * - this gets any extra refs it needs on an op
82 */
83int fscache_submit_exclusive_op(struct fscache_object *object,
84 struct fscache_operation *op)
85{
86 int ret;
87
88 _enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
89
90 spin_lock(&object->lock);
91 ASSERTCMP(object->n_ops, >=, object->n_in_progress);
92 ASSERTCMP(object->n_ops, >=, object->n_exclusive);
93
94 ret = -ENOBUFS;
95 if (fscache_object_is_active(object)) {
96 op->object = object;
97 object->n_ops++;
98 object->n_exclusive++; /* reads and writes must wait */
99
100 if (object->n_ops > 0) {
101 atomic_inc(&op->usage);
102 list_add_tail(&op->pend_link, &object->pending_ops);
103 fscache_stat(&fscache_n_op_pend);
104 } else if (!list_empty(&object->pending_ops)) {
105 atomic_inc(&op->usage);
106 list_add_tail(&op->pend_link, &object->pending_ops);
107 fscache_stat(&fscache_n_op_pend);
108 fscache_start_operations(object);
109 } else {
110 ASSERTCMP(object->n_in_progress, ==, 0);
111 fscache_run_op(object, op);
112 }
113
114 /* need to issue a new write op after this */
115 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
116 ret = 0;
117 } else if (object->state == FSCACHE_OBJECT_CREATING) {
118 op->object = object;
119 object->n_ops++;
120 object->n_exclusive++; /* reads and writes must wait */
121 atomic_inc(&op->usage);
122 list_add_tail(&op->pend_link, &object->pending_ops);
123 fscache_stat(&fscache_n_op_pend);
124 ret = 0;
125 } else {
126 /* not allowed to submit ops in any other state */
127 BUG();
128 }
129
130 spin_unlock(&object->lock);
131 return ret;
132}
133
134/*
135 * report an unexpected submission
136 */
137static void fscache_report_unexpected_submission(struct fscache_object *object,
138 struct fscache_operation *op,
139 unsigned long ostate)
140{
141 static bool once_only;
142 struct fscache_operation *p;
143 unsigned n;
144
145 if (once_only)
146 return;
147 once_only = true;
148
149 kdebug("unexpected submission OP%x [OBJ%x %s]",
150 op->debug_id, object->debug_id,
151 fscache_object_states[object->state]);
152 kdebug("objstate=%s [%s]",
153 fscache_object_states[object->state],
154 fscache_object_states[ostate]);
155 kdebug("objflags=%lx", object->flags);
156 kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
157 kdebug("ops=%u inp=%u exc=%u",
158 object->n_ops, object->n_in_progress, object->n_exclusive);
159
160 if (!list_empty(&object->pending_ops)) {
161 n = 0;
162 list_for_each_entry(p, &object->pending_ops, pend_link) {
163 ASSERTCMP(p->object, ==, object);
164 kdebug("%p %p", op->processor, op->release);
165 n++;
166 }
167
168 kdebug("n=%u", n);
169 }
170
171 dump_stack();
172}
173
174/*
175 * submit an operation for an object
176 * - objects may be submitted only in the following states:
177 * - during object creation (write ops may be submitted)
178 * - whilst the object is active
179 * - after an I/O error incurred in one of the two above states (op rejected)
180 * - this gets any extra refs it needs on an op
181 */
182int fscache_submit_op(struct fscache_object *object,
183 struct fscache_operation *op)
184{
185 unsigned long ostate;
186 int ret;
187
188 _enter("{OBJ%x OP%x},{%u}",
189 object->debug_id, op->debug_id, atomic_read(&op->usage));
190
191 ASSERTCMP(atomic_read(&op->usage), >, 0);
192
193 spin_lock(&object->lock);
194 ASSERTCMP(object->n_ops, >=, object->n_in_progress);
195 ASSERTCMP(object->n_ops, >=, object->n_exclusive);
196
197 ostate = object->state;
198 smp_rmb();
199
200 if (fscache_object_is_active(object)) {
201 op->object = object;
202 object->n_ops++;
203
204 if (object->n_exclusive > 0) {
205 atomic_inc(&op->usage);
206 list_add_tail(&op->pend_link, &object->pending_ops);
207 fscache_stat(&fscache_n_op_pend);
208 } else if (!list_empty(&object->pending_ops)) {
209 atomic_inc(&op->usage);
210 list_add_tail(&op->pend_link, &object->pending_ops);
211 fscache_stat(&fscache_n_op_pend);
212 fscache_start_operations(object);
213 } else {
214 ASSERTCMP(object->n_exclusive, ==, 0);
215 fscache_run_op(object, op);
216 }
217 ret = 0;
218 } else if (object->state == FSCACHE_OBJECT_CREATING) {
219 op->object = object;
220 object->n_ops++;
221 atomic_inc(&op->usage);
222 list_add_tail(&op->pend_link, &object->pending_ops);
223 fscache_stat(&fscache_n_op_pend);
224 ret = 0;
225 } else if (!test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
226 fscache_report_unexpected_submission(object, op, ostate);
227 ASSERT(!fscache_object_is_active(object));
228 ret = -ENOBUFS;
229 } else {
230 ret = -ENOBUFS;
231 }
232
233 spin_unlock(&object->lock);
234 return ret;
235}
236
237/*
238 * queue an object for withdrawal on error, aborting all following asynchronous
239 * operations
240 */
241void fscache_abort_object(struct fscache_object *object)
242{
243 _enter("{OBJ%x}", object->debug_id);
244
245 fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
246}
247
248/*
249 * jump start the operation processing on an object
250 * - caller must hold object->lock
251 */
252void fscache_start_operations(struct fscache_object *object)
253{
254 struct fscache_operation *op;
255 bool stop = false;
256
257 while (!list_empty(&object->pending_ops) && !stop) {
258 op = list_entry(object->pending_ops.next,
259 struct fscache_operation, pend_link);
260
261 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
262 if (object->n_in_progress > 0)
263 break;
264 stop = true;
265 }
266 list_del_init(&op->pend_link);
267 object->n_in_progress++;
268
269 if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
270 wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
271 if (op->processor)
272 fscache_enqueue_operation(op);
273
274 /* the pending queue was holding a ref on the object */
275 fscache_put_operation(op);
276 }
277
278 ASSERTCMP(object->n_in_progress, <=, object->n_ops);
279
280 _debug("woke %d ops on OBJ%x",
281 object->n_in_progress, object->debug_id);
282}
283
284/*
285 * release an operation
286 * - queues pending ops if this is the last in-progress op
287 */
288void fscache_put_operation(struct fscache_operation *op)
289{
290 struct fscache_object *object;
291 struct fscache_cache *cache;
292
293 _enter("{OBJ%x OP%x,%d}",
294 op->object->debug_id, op->debug_id, atomic_read(&op->usage));
295
296 ASSERTCMP(atomic_read(&op->usage), >, 0);
297
298 if (!atomic_dec_and_test(&op->usage))
299 return;
300
301 _debug("PUT OP");
302 if (test_and_set_bit(FSCACHE_OP_DEAD, &op->flags))
303 BUG();
304
305 fscache_stat(&fscache_n_op_release);
306
307 if (op->release) {
308 op->release(op);
309 op->release = NULL;
310 }
311
312 object = op->object;
313
314 /* now... we may get called with the object spinlock held, so we
315 * complete the cleanup here only if we can immediately acquire the
316 * lock, and defer it otherwise */
317 if (!spin_trylock(&object->lock)) {
318 _debug("defer put");
319 fscache_stat(&fscache_n_op_deferred_release);
320
321 cache = object->cache;
322 spin_lock(&cache->op_gc_list_lock);
323 list_add_tail(&op->pend_link, &cache->op_gc_list);
324 spin_unlock(&cache->op_gc_list_lock);
325 schedule_work(&cache->op_gc);
326 _leave(" [defer]");
327 return;
328 }
329
330 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
331 ASSERTCMP(object->n_exclusive, >, 0);
332 object->n_exclusive--;
333 }
334
335 ASSERTCMP(object->n_in_progress, >, 0);
336 object->n_in_progress--;
337 if (object->n_in_progress == 0)
338 fscache_start_operations(object);
339
340 ASSERTCMP(object->n_ops, >, 0);
341 object->n_ops--;
342 if (object->n_ops == 0)
343 fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
344
345 spin_unlock(&object->lock);
346
347 kfree(op);
348 _leave(" [done]");
349}
350EXPORT_SYMBOL(fscache_put_operation);
351
352/*
353 * garbage collect operations that have had their release deferred
354 */
355void fscache_operation_gc(struct work_struct *work)
356{
357 struct fscache_operation *op;
358 struct fscache_object *object;
359 struct fscache_cache *cache =
360 container_of(work, struct fscache_cache, op_gc);
361 int count = 0;
362
363 _enter("");
364
365 do {
366 spin_lock(&cache->op_gc_list_lock);
367 if (list_empty(&cache->op_gc_list)) {
368 spin_unlock(&cache->op_gc_list_lock);
369 break;
370 }
371
372 op = list_entry(cache->op_gc_list.next,
373 struct fscache_operation, pend_link);
374 list_del(&op->pend_link);
375 spin_unlock(&cache->op_gc_list_lock);
376
377 object = op->object;
378
379 _debug("GC DEFERRED REL OBJ%x OP%x",
380 object->debug_id, op->debug_id);
381 fscache_stat(&fscache_n_op_gc);
382
383 ASSERTCMP(atomic_read(&op->usage), ==, 0);
384
385 spin_lock(&object->lock);
386 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
387 ASSERTCMP(object->n_exclusive, >, 0);
388 object->n_exclusive--;
389 }
390
391 ASSERTCMP(object->n_in_progress, >, 0);
392 object->n_in_progress--;
393 if (object->n_in_progress == 0)
394 fscache_start_operations(object);
395
396 ASSERTCMP(object->n_ops, >, 0);
397 object->n_ops--;
398 if (object->n_ops == 0)
399 fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
400
401 spin_unlock(&object->lock);
402
403 } while (count++ < 20);
404
405 if (!list_empty(&cache->op_gc_list))
406 schedule_work(&cache->op_gc);
407
408 _leave("");
409}
410
411/*
412 * allow the slow work item processor to get a ref on an operation
413 */
414static int fscache_op_get_ref(struct slow_work *work)
415{
416 struct fscache_operation *op =
417 container_of(work, struct fscache_operation, slow_work);
418
419 atomic_inc(&op->usage);
420 return 0;
421}
422
423/*
424 * allow the slow work item processor to discard a ref on an operation
425 */
426static void fscache_op_put_ref(struct slow_work *work)
427{
428 struct fscache_operation *op =
429 container_of(work, struct fscache_operation, slow_work);
430
431 fscache_put_operation(op);
432}
433
434/*
435 * execute an operation using the slow thread pool to provide processing context
436 * - the caller holds a ref to this object, so we don't need to hold one
437 */
438static void fscache_op_execute(struct slow_work *work)
439{
440 struct fscache_operation *op =
441 container_of(work, struct fscache_operation, slow_work);
442 unsigned long start;
443
444 _enter("{OBJ%x OP%x,%d}",
445 op->object->debug_id, op->debug_id, atomic_read(&op->usage));
446
447 ASSERT(op->processor != NULL);
448 start = jiffies;
449 op->processor(op);
450 fscache_hist(fscache_ops_histogram, start);
451
452 _leave("");
453}
454
455const struct slow_work_ops fscache_op_slow_work_ops = {
456 .get_ref = fscache_op_get_ref,
457 .put_ref = fscache_op_put_ref,
458 .execute = fscache_op_execute,
459};
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
new file mode 100644
index 000000000000..2568e0eb644f
--- /dev/null
+++ b/fs/fscache/page.c
@@ -0,0 +1,816 @@
1/* Cache page management and data I/O routines
2 *
3 * Copyright (C) 2004-2008 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL PAGE
13#include <linux/module.h>
14#include <linux/fscache-cache.h>
15#include <linux/buffer_head.h>
16#include <linux/pagevec.h>
17#include "internal.h"
18
19/*
20 * check to see if a page is being written to the cache
21 */
22bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
23{
24 void *val;
25
26 rcu_read_lock();
27 val = radix_tree_lookup(&cookie->stores, page->index);
28 rcu_read_unlock();
29
30 return val != NULL;
31}
32EXPORT_SYMBOL(__fscache_check_page_write);
33
34/*
35 * wait for a page to finish being written to the cache
36 */
37void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
38{
39 wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
40
41 wait_event(*wq, !__fscache_check_page_write(cookie, page));
42}
43EXPORT_SYMBOL(__fscache_wait_on_page_write);
44
45/*
46 * note that a page has finished being written to the cache
47 */
48static void fscache_end_page_write(struct fscache_cookie *cookie, struct page *page)
49{
50 struct page *xpage;
51
52 spin_lock(&cookie->lock);
53 xpage = radix_tree_delete(&cookie->stores, page->index);
54 spin_unlock(&cookie->lock);
55 ASSERT(xpage != NULL);
56
57 wake_up_bit(&cookie->flags, 0);
58}
59
60/*
61 * actually apply the changed attributes to a cache object
62 */
63static void fscache_attr_changed_op(struct fscache_operation *op)
64{
65 struct fscache_object *object = op->object;
66
67 _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
68
69 fscache_stat(&fscache_n_attr_changed_calls);
70
71 if (fscache_object_is_active(object) &&
72 object->cache->ops->attr_changed(object) < 0)
73 fscache_abort_object(object);
74
75 _leave("");
76}
77
78/*
79 * notification that the attributes on an object have changed
80 */
81int __fscache_attr_changed(struct fscache_cookie *cookie)
82{
83 struct fscache_operation *op;
84 struct fscache_object *object;
85
86 _enter("%p", cookie);
87
88 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
89
90 fscache_stat(&fscache_n_attr_changed);
91
92 op = kzalloc(sizeof(*op), GFP_KERNEL);
93 if (!op) {
94 fscache_stat(&fscache_n_attr_changed_nomem);
95 _leave(" = -ENOMEM");
96 return -ENOMEM;
97 }
98
99 fscache_operation_init(op, NULL);
100 fscache_operation_init_slow(op, fscache_attr_changed_op);
101 op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE);
102
103 spin_lock(&cookie->lock);
104
105 if (hlist_empty(&cookie->backing_objects))
106 goto nobufs;
107 object = hlist_entry(cookie->backing_objects.first,
108 struct fscache_object, cookie_link);
109
110 if (fscache_submit_exclusive_op(object, op) < 0)
111 goto nobufs;
112 spin_unlock(&cookie->lock);
113 fscache_stat(&fscache_n_attr_changed_ok);
114 fscache_put_operation(op);
115 _leave(" = 0");
116 return 0;
117
118nobufs:
119 spin_unlock(&cookie->lock);
120 kfree(op);
121 fscache_stat(&fscache_n_attr_changed_nobufs);
122 _leave(" = %d", -ENOBUFS);
123 return -ENOBUFS;
124}
125EXPORT_SYMBOL(__fscache_attr_changed);
126
127/*
128 * handle secondary execution given to a retrieval op on behalf of the
129 * cache
130 */
131static void fscache_retrieval_work(struct work_struct *work)
132{
133 struct fscache_retrieval *op =
134 container_of(work, struct fscache_retrieval, op.fast_work);
135 unsigned long start;
136
137 _enter("{OP%x}", op->op.debug_id);
138
139 start = jiffies;
140 op->op.processor(&op->op);
141 fscache_hist(fscache_ops_histogram, start);
142 fscache_put_operation(&op->op);
143}
144
145/*
146 * release a retrieval op reference
147 */
148static void fscache_release_retrieval_op(struct fscache_operation *_op)
149{
150 struct fscache_retrieval *op =
151 container_of(_op, struct fscache_retrieval, op);
152
153 _enter("{OP%x}", op->op.debug_id);
154
155 fscache_hist(fscache_retrieval_histogram, op->start_time);
156 if (op->context)
157 fscache_put_context(op->op.object->cookie, op->context);
158
159 _leave("");
160}
161
162/*
163 * allocate a retrieval op
164 */
165static struct fscache_retrieval *fscache_alloc_retrieval(
166 struct address_space *mapping,
167 fscache_rw_complete_t end_io_func,
168 void *context)
169{
170 struct fscache_retrieval *op;
171
172 /* allocate a retrieval operation and attempt to submit it */
173 op = kzalloc(sizeof(*op), GFP_NOIO);
174 if (!op) {
175 fscache_stat(&fscache_n_retrievals_nomem);
176 return NULL;
177 }
178
179 fscache_operation_init(&op->op, fscache_release_retrieval_op);
180 op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
181 op->mapping = mapping;
182 op->end_io_func = end_io_func;
183 op->context = context;
184 op->start_time = jiffies;
185 INIT_WORK(&op->op.fast_work, fscache_retrieval_work);
186 INIT_LIST_HEAD(&op->to_do);
187 return op;
188}
189
190/*
191 * wait for a deferred lookup to complete
192 */
193static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
194{
195 unsigned long jif;
196
197 _enter("");
198
199 if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
200 _leave(" = 0 [imm]");
201 return 0;
202 }
203
204 fscache_stat(&fscache_n_retrievals_wait);
205
206 jif = jiffies;
207 if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
208 fscache_wait_bit_interruptible,
209 TASK_INTERRUPTIBLE) != 0) {
210 fscache_stat(&fscache_n_retrievals_intr);
211 _leave(" = -ERESTARTSYS");
212 return -ERESTARTSYS;
213 }
214
215 ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
216
217 smp_rmb();
218 fscache_hist(fscache_retrieval_delay_histogram, jif);
219 _leave(" = 0 [dly]");
220 return 0;
221}
222
223/*
224 * read a page from the cache or allocate a block in which to store it
225 * - we return:
226 * -ENOMEM - out of memory, nothing done
227 * -ERESTARTSYS - interrupted
228 * -ENOBUFS - no backing object available in which to cache the block
229 * -ENODATA - no data available in the backing object for this block
230 * 0 - dispatched a read - it'll call end_io_func() when finished
231 */
232int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
233 struct page *page,
234 fscache_rw_complete_t end_io_func,
235 void *context,
236 gfp_t gfp)
237{
238 struct fscache_retrieval *op;
239 struct fscache_object *object;
240 int ret;
241
242 _enter("%p,%p,,,", cookie, page);
243
244 fscache_stat(&fscache_n_retrievals);
245
246 if (hlist_empty(&cookie->backing_objects))
247 goto nobufs;
248
249 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
250 ASSERTCMP(page, !=, NULL);
251
252 if (fscache_wait_for_deferred_lookup(cookie) < 0)
253 return -ERESTARTSYS;
254
255 op = fscache_alloc_retrieval(page->mapping, end_io_func, context);
256 if (!op) {
257 _leave(" = -ENOMEM");
258 return -ENOMEM;
259 }
260
261 spin_lock(&cookie->lock);
262
263 if (hlist_empty(&cookie->backing_objects))
264 goto nobufs_unlock;
265 object = hlist_entry(cookie->backing_objects.first,
266 struct fscache_object, cookie_link);
267
268 ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
269
270 if (fscache_submit_op(object, &op->op) < 0)
271 goto nobufs_unlock;
272 spin_unlock(&cookie->lock);
273
274 fscache_stat(&fscache_n_retrieval_ops);
275
276 /* pin the netfs read context in case we need to do the actual netfs
277 * read because we've encountered a cache read failure */
278 fscache_get_context(object->cookie, op->context);
279
280 /* we wait for the operation to become active, and then process it
281 * *here*, in this thread, and not in the thread pool */
282 if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
283 _debug(">>> WT");
284 fscache_stat(&fscache_n_retrieval_op_waits);
285 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
286 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
287 _debug("<<< GO");
288 }
289
290 /* ask the cache to honour the operation */
291 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
292 ret = object->cache->ops->allocate_page(op, page, gfp);
293 if (ret == 0)
294 ret = -ENODATA;
295 } else {
296 ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
297 }
298
299 if (ret == -ENOMEM)
300 fscache_stat(&fscache_n_retrievals_nomem);
301 else if (ret == -ERESTARTSYS)
302 fscache_stat(&fscache_n_retrievals_intr);
303 else if (ret == -ENODATA)
304 fscache_stat(&fscache_n_retrievals_nodata);
305 else if (ret < 0)
306 fscache_stat(&fscache_n_retrievals_nobufs);
307 else
308 fscache_stat(&fscache_n_retrievals_ok);
309
310 fscache_put_retrieval(op);
311 _leave(" = %d", ret);
312 return ret;
313
314nobufs_unlock:
315 spin_unlock(&cookie->lock);
316 kfree(op);
317nobufs:
318 fscache_stat(&fscache_n_retrievals_nobufs);
319 _leave(" = -ENOBUFS");
320 return -ENOBUFS;
321}
322EXPORT_SYMBOL(__fscache_read_or_alloc_page);
323
324/*
325 * read a list of page from the cache or allocate a block in which to store
326 * them
327 * - we return:
328 * -ENOMEM - out of memory, some pages may be being read
329 * -ERESTARTSYS - interrupted, some pages may be being read
330 * -ENOBUFS - no backing object or space available in which to cache any
331 * pages not being read
332 * -ENODATA - no data available in the backing object for some or all of
333 * the pages
334 * 0 - dispatched a read on all pages
335 *
336 * end_io_func() will be called for each page read from the cache as it is
337 * finishes being read
338 *
339 * any pages for which a read is dispatched will be removed from pages and
340 * nr_pages
341 */
342int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
343 struct address_space *mapping,
344 struct list_head *pages,
345 unsigned *nr_pages,
346 fscache_rw_complete_t end_io_func,
347 void *context,
348 gfp_t gfp)
349{
350 fscache_pages_retrieval_func_t func;
351 struct fscache_retrieval *op;
352 struct fscache_object *object;
353 int ret;
354
355 _enter("%p,,%d,,,", cookie, *nr_pages);
356
357 fscache_stat(&fscache_n_retrievals);
358
359 if (hlist_empty(&cookie->backing_objects))
360 goto nobufs;
361
362 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
363 ASSERTCMP(*nr_pages, >, 0);
364 ASSERT(!list_empty(pages));
365
366 if (fscache_wait_for_deferred_lookup(cookie) < 0)
367 return -ERESTARTSYS;
368
369 op = fscache_alloc_retrieval(mapping, end_io_func, context);
370 if (!op)
371 return -ENOMEM;
372
373 spin_lock(&cookie->lock);
374
375 if (hlist_empty(&cookie->backing_objects))
376 goto nobufs_unlock;
377 object = hlist_entry(cookie->backing_objects.first,
378 struct fscache_object, cookie_link);
379
380 if (fscache_submit_op(object, &op->op) < 0)
381 goto nobufs_unlock;
382 spin_unlock(&cookie->lock);
383
384 fscache_stat(&fscache_n_retrieval_ops);
385
386 /* pin the netfs read context in case we need to do the actual netfs
387 * read because we've encountered a cache read failure */
388 fscache_get_context(object->cookie, op->context);
389
390 /* we wait for the operation to become active, and then process it
391 * *here*, in this thread, and not in the thread pool */
392 if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
393 _debug(">>> WT");
394 fscache_stat(&fscache_n_retrieval_op_waits);
395 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
396 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
397 _debug("<<< GO");
398 }
399
400 /* ask the cache to honour the operation */
401 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags))
402 func = object->cache->ops->allocate_pages;
403 else
404 func = object->cache->ops->read_or_alloc_pages;
405 ret = func(op, pages, nr_pages, gfp);
406
407 if (ret == -ENOMEM)
408 fscache_stat(&fscache_n_retrievals_nomem);
409 else if (ret == -ERESTARTSYS)
410 fscache_stat(&fscache_n_retrievals_intr);
411 else if (ret == -ENODATA)
412 fscache_stat(&fscache_n_retrievals_nodata);
413 else if (ret < 0)
414 fscache_stat(&fscache_n_retrievals_nobufs);
415 else
416 fscache_stat(&fscache_n_retrievals_ok);
417
418 fscache_put_retrieval(op);
419 _leave(" = %d", ret);
420 return ret;
421
422nobufs_unlock:
423 spin_unlock(&cookie->lock);
424 kfree(op);
425nobufs:
426 fscache_stat(&fscache_n_retrievals_nobufs);
427 _leave(" = -ENOBUFS");
428 return -ENOBUFS;
429}
430EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
431
432/*
433 * allocate a block in the cache on which to store a page
434 * - we return:
435 * -ENOMEM - out of memory, nothing done
436 * -ERESTARTSYS - interrupted
437 * -ENOBUFS - no backing object available in which to cache the block
438 * 0 - block allocated
439 */
440int __fscache_alloc_page(struct fscache_cookie *cookie,
441 struct page *page,
442 gfp_t gfp)
443{
444 struct fscache_retrieval *op;
445 struct fscache_object *object;
446 int ret;
447
448 _enter("%p,%p,,,", cookie, page);
449
450 fscache_stat(&fscache_n_allocs);
451
452 if (hlist_empty(&cookie->backing_objects))
453 goto nobufs;
454
455 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
456 ASSERTCMP(page, !=, NULL);
457
458 if (fscache_wait_for_deferred_lookup(cookie) < 0)
459 return -ERESTARTSYS;
460
461 op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
462 if (!op)
463 return -ENOMEM;
464
465 spin_lock(&cookie->lock);
466
467 if (hlist_empty(&cookie->backing_objects))
468 goto nobufs_unlock;
469 object = hlist_entry(cookie->backing_objects.first,
470 struct fscache_object, cookie_link);
471
472 if (fscache_submit_op(object, &op->op) < 0)
473 goto nobufs_unlock;
474 spin_unlock(&cookie->lock);
475
476 fscache_stat(&fscache_n_alloc_ops);
477
478 if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
479 _debug(">>> WT");
480 fscache_stat(&fscache_n_alloc_op_waits);
481 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
482 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
483 _debug("<<< GO");
484 }
485
486 /* ask the cache to honour the operation */
487 ret = object->cache->ops->allocate_page(op, page, gfp);
488
489 if (ret < 0)
490 fscache_stat(&fscache_n_allocs_nobufs);
491 else
492 fscache_stat(&fscache_n_allocs_ok);
493
494 fscache_put_retrieval(op);
495 _leave(" = %d", ret);
496 return ret;
497
498nobufs_unlock:
499 spin_unlock(&cookie->lock);
500 kfree(op);
501nobufs:
502 fscache_stat(&fscache_n_allocs_nobufs);
503 _leave(" = -ENOBUFS");
504 return -ENOBUFS;
505}
506EXPORT_SYMBOL(__fscache_alloc_page);
507
508/*
509 * release a write op reference
510 */
511static void fscache_release_write_op(struct fscache_operation *_op)
512{
513 _enter("{OP%x}", _op->debug_id);
514}
515
516/*
517 * perform the background storage of a page into the cache
518 */
519static void fscache_write_op(struct fscache_operation *_op)
520{
521 struct fscache_storage *op =
522 container_of(_op, struct fscache_storage, op);
523 struct fscache_object *object = op->op.object;
524 struct fscache_cookie *cookie = object->cookie;
525 struct page *page;
526 unsigned n;
527 void *results[1];
528 int ret;
529
530 _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
531
532 spin_lock(&cookie->lock);
533 spin_lock(&object->lock);
534
535 if (!fscache_object_is_active(object)) {
536 spin_unlock(&object->lock);
537 spin_unlock(&cookie->lock);
538 _leave("");
539 return;
540 }
541
542 fscache_stat(&fscache_n_store_calls);
543
544 /* find a page to store */
545 page = NULL;
546 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
547 FSCACHE_COOKIE_PENDING_TAG);
548 if (n != 1)
549 goto superseded;
550 page = results[0];
551 _debug("gang %d [%lx]", n, page->index);
552 if (page->index > op->store_limit)
553 goto superseded;
554
555 radix_tree_tag_clear(&cookie->stores, page->index,
556 FSCACHE_COOKIE_PENDING_TAG);
557
558 spin_unlock(&object->lock);
559 spin_unlock(&cookie->lock);
560
561 if (page) {
562 ret = object->cache->ops->write_page(op, page);
563 fscache_end_page_write(cookie, page);
564 page_cache_release(page);
565 if (ret < 0)
566 fscache_abort_object(object);
567 else
568 fscache_enqueue_operation(&op->op);
569 }
570
571 _leave("");
572 return;
573
574superseded:
575 /* this writer is going away and there aren't any more things to
576 * write */
577 _debug("cease");
578 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
579 spin_unlock(&object->lock);
580 spin_unlock(&cookie->lock);
581 _leave("");
582}
583
584/*
585 * request a page be stored in the cache
586 * - returns:
587 * -ENOMEM - out of memory, nothing done
588 * -ENOBUFS - no backing object available in which to cache the page
589 * 0 - dispatched a write - it'll call end_io_func() when finished
590 *
591 * if the cookie still has a backing object at this point, that object can be
592 * in one of a few states with respect to storage processing:
593 *
594 * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
595 * set)
596 *
597 * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred
598 * fill op)
599 *
600 * (b) writes deferred till post-creation (mark page for writing and
601 * return immediately)
602 *
603 * (2) negative lookup, object created, initial fill being made from netfs
604 * (FSCACHE_COOKIE_INITIAL_FILL is set)
605 *
606 * (a) fill point not yet reached this page (mark page for writing and
607 * return)
608 *
609 * (b) fill point passed this page (queue op to store this page)
610 *
611 * (3) object extant (queue op to store this page)
612 *
613 * any other state is invalid
614 */
615int __fscache_write_page(struct fscache_cookie *cookie,
616 struct page *page,
617 gfp_t gfp)
618{
619 struct fscache_storage *op;
620 struct fscache_object *object;
621 int ret;
622
623 _enter("%p,%x,", cookie, (u32) page->flags);
624
625 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
626 ASSERT(PageFsCache(page));
627
628 fscache_stat(&fscache_n_stores);
629
630 op = kzalloc(sizeof(*op), GFP_NOIO);
631 if (!op)
632 goto nomem;
633
634 fscache_operation_init(&op->op, fscache_release_write_op);
635 fscache_operation_init_slow(&op->op, fscache_write_op);
636 op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING);
637
638 ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
639 if (ret < 0)
640 goto nomem_free;
641
642 ret = -ENOBUFS;
643 spin_lock(&cookie->lock);
644
645 if (hlist_empty(&cookie->backing_objects))
646 goto nobufs;
647 object = hlist_entry(cookie->backing_objects.first,
648 struct fscache_object, cookie_link);
649 if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
650 goto nobufs;
651
652 /* add the page to the pending-storage radix tree on the backing
653 * object */
654 spin_lock(&object->lock);
655
656 _debug("store limit %llx", (unsigned long long) object->store_limit);
657
658 ret = radix_tree_insert(&cookie->stores, page->index, page);
659 if (ret < 0) {
660 if (ret == -EEXIST)
661 goto already_queued;
662 _debug("insert failed %d", ret);
663 goto nobufs_unlock_obj;
664 }
665
666 radix_tree_tag_set(&cookie->stores, page->index,
667 FSCACHE_COOKIE_PENDING_TAG);
668 page_cache_get(page);
669
670 /* we only want one writer at a time, but we do need to queue new
671 * writers after exclusive ops */
672 if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
673 goto already_pending;
674
675 spin_unlock(&object->lock);
676
677 op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
678 op->store_limit = object->store_limit;
679
680 if (fscache_submit_op(object, &op->op) < 0)
681 goto submit_failed;
682
683 spin_unlock(&cookie->lock);
684 radix_tree_preload_end();
685 fscache_stat(&fscache_n_store_ops);
686 fscache_stat(&fscache_n_stores_ok);
687
688 /* the slow work queue now carries its own ref on the object */
689 fscache_put_operation(&op->op);
690 _leave(" = 0");
691 return 0;
692
693already_queued:
694 fscache_stat(&fscache_n_stores_again);
695already_pending:
696 spin_unlock(&object->lock);
697 spin_unlock(&cookie->lock);
698 radix_tree_preload_end();
699 kfree(op);
700 fscache_stat(&fscache_n_stores_ok);
701 _leave(" = 0");
702 return 0;
703
704submit_failed:
705 radix_tree_delete(&cookie->stores, page->index);
706 page_cache_release(page);
707 ret = -ENOBUFS;
708 goto nobufs;
709
710nobufs_unlock_obj:
711 spin_unlock(&object->lock);
712nobufs:
713 spin_unlock(&cookie->lock);
714 radix_tree_preload_end();
715 kfree(op);
716 fscache_stat(&fscache_n_stores_nobufs);
717 _leave(" = -ENOBUFS");
718 return -ENOBUFS;
719
720nomem_free:
721 kfree(op);
722nomem:
723 fscache_stat(&fscache_n_stores_oom);
724 _leave(" = -ENOMEM");
725 return -ENOMEM;
726}
727EXPORT_SYMBOL(__fscache_write_page);
728
729/*
730 * remove a page from the cache
731 */
732void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
733{
734 struct fscache_object *object;
735
736 _enter(",%p", page);
737
738 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
739 ASSERTCMP(page, !=, NULL);
740
741 fscache_stat(&fscache_n_uncaches);
742
743 /* cache withdrawal may beat us to it */
744 if (!PageFsCache(page))
745 goto done;
746
747 /* get the object */
748 spin_lock(&cookie->lock);
749
750 if (hlist_empty(&cookie->backing_objects)) {
751 ClearPageFsCache(page);
752 goto done_unlock;
753 }
754
755 object = hlist_entry(cookie->backing_objects.first,
756 struct fscache_object, cookie_link);
757
758 /* there might now be stuff on disk we could read */
759 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
760
761 /* only invoke the cache backend if we managed to mark the page
762 * uncached here; this deals with synchronisation vs withdrawal */
763 if (TestClearPageFsCache(page) &&
764 object->cache->ops->uncache_page) {
765 /* the cache backend releases the cookie lock */
766 object->cache->ops->uncache_page(object, page);
767 goto done;
768 }
769
770done_unlock:
771 spin_unlock(&cookie->lock);
772done:
773 _leave("");
774}
775EXPORT_SYMBOL(__fscache_uncache_page);
776
777/**
778 * fscache_mark_pages_cached - Mark pages as being cached
779 * @op: The retrieval op pages are being marked for
780 * @pagevec: The pages to be marked
781 *
782 * Mark a bunch of netfs pages as being cached. After this is called,
783 * the netfs must call fscache_uncache_page() to remove the mark.
784 */
785void fscache_mark_pages_cached(struct fscache_retrieval *op,
786 struct pagevec *pagevec)
787{
788 struct fscache_cookie *cookie = op->op.object->cookie;
789 unsigned long loop;
790
791#ifdef CONFIG_FSCACHE_STATS
792 atomic_add(pagevec->nr, &fscache_n_marks);
793#endif
794
795 for (loop = 0; loop < pagevec->nr; loop++) {
796 struct page *page = pagevec->pages[loop];
797
798 _debug("- mark %p{%lx}", page, page->index);
799 if (TestSetPageFsCache(page)) {
800 static bool once_only;
801 if (!once_only) {
802 once_only = true;
803 printk(KERN_WARNING "FS-Cache:"
804 " Cookie type %s marked page %lx"
805 " multiple times\n",
806 cookie->def->name, page->index);
807 }
808 }
809 }
810
811 if (cookie->def->mark_pages_cached)
812 cookie->def->mark_pages_cached(cookie->netfs_data,
813 op->mapping, pagevec);
814 pagevec_reinit(pagevec);
815}
816EXPORT_SYMBOL(fscache_mark_pages_cached);
diff --git a/fs/fscache/proc.c b/fs/fscache/proc.c
new file mode 100644
index 000000000000..beeab44bc31a
--- /dev/null
+++ b/fs/fscache/proc.c
@@ -0,0 +1,68 @@
1/* FS-Cache statistics viewing interface
2 *
3 * Copyright (C) 2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL OPERATION
13#include <linux/module.h>
14#include <linux/proc_fs.h>
15#include <linux/seq_file.h>
16#include "internal.h"
17
18/*
19 * initialise the /proc/fs/fscache/ directory
20 */
21int __init fscache_proc_init(void)
22{
23 _enter("");
24
25 if (!proc_mkdir("fs/fscache", NULL))
26 goto error_dir;
27
28#ifdef CONFIG_FSCACHE_STATS
29 if (!proc_create("fs/fscache/stats", S_IFREG | 0444, NULL,
30 &fscache_stats_fops))
31 goto error_stats;
32#endif
33
34#ifdef CONFIG_FSCACHE_HISTOGRAM
35 if (!proc_create("fs/fscache/histogram", S_IFREG | 0444, NULL,
36 &fscache_histogram_fops))
37 goto error_histogram;
38#endif
39
40 _leave(" = 0");
41 return 0;
42
43#ifdef CONFIG_FSCACHE_HISTOGRAM
44error_histogram:
45#endif
46#ifdef CONFIG_FSCACHE_STATS
47 remove_proc_entry("fs/fscache/stats", NULL);
48error_stats:
49#endif
50 remove_proc_entry("fs/fscache", NULL);
51error_dir:
52 _leave(" = -ENOMEM");
53 return -ENOMEM;
54}
55
56/*
57 * clean up the /proc/fs/fscache/ directory
58 */
59void fscache_proc_cleanup(void)
60{
61#ifdef CONFIG_FSCACHE_HISTOGRAM
62 remove_proc_entry("fs/fscache/histogram", NULL);
63#endif
64#ifdef CONFIG_FSCACHE_STATS
65 remove_proc_entry("fs/fscache/stats", NULL);
66#endif
67 remove_proc_entry("fs/fscache", NULL);
68}
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
new file mode 100644
index 000000000000..65deb99e756b
--- /dev/null
+++ b/fs/fscache/stats.c
@@ -0,0 +1,212 @@
1/* FS-Cache statistics
2 *
3 * Copyright (C) 2007 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL THREAD
13#include <linux/module.h>
14#include <linux/proc_fs.h>
15#include <linux/seq_file.h>
16#include "internal.h"
17
18/*
19 * operation counters
20 */
21atomic_t fscache_n_op_pend;
22atomic_t fscache_n_op_run;
23atomic_t fscache_n_op_enqueue;
24atomic_t fscache_n_op_requeue;
25atomic_t fscache_n_op_deferred_release;
26atomic_t fscache_n_op_release;
27atomic_t fscache_n_op_gc;
28
29atomic_t fscache_n_attr_changed;
30atomic_t fscache_n_attr_changed_ok;
31atomic_t fscache_n_attr_changed_nobufs;
32atomic_t fscache_n_attr_changed_nomem;
33atomic_t fscache_n_attr_changed_calls;
34
35atomic_t fscache_n_allocs;
36atomic_t fscache_n_allocs_ok;
37atomic_t fscache_n_allocs_wait;
38atomic_t fscache_n_allocs_nobufs;
39atomic_t fscache_n_alloc_ops;
40atomic_t fscache_n_alloc_op_waits;
41
42atomic_t fscache_n_retrievals;
43atomic_t fscache_n_retrievals_ok;
44atomic_t fscache_n_retrievals_wait;
45atomic_t fscache_n_retrievals_nodata;
46atomic_t fscache_n_retrievals_nobufs;
47atomic_t fscache_n_retrievals_intr;
48atomic_t fscache_n_retrievals_nomem;
49atomic_t fscache_n_retrieval_ops;
50atomic_t fscache_n_retrieval_op_waits;
51
52atomic_t fscache_n_stores;
53atomic_t fscache_n_stores_ok;
54atomic_t fscache_n_stores_again;
55atomic_t fscache_n_stores_nobufs;
56atomic_t fscache_n_stores_oom;
57atomic_t fscache_n_store_ops;
58atomic_t fscache_n_store_calls;
59
60atomic_t fscache_n_marks;
61atomic_t fscache_n_uncaches;
62
63atomic_t fscache_n_acquires;
64atomic_t fscache_n_acquires_null;
65atomic_t fscache_n_acquires_no_cache;
66atomic_t fscache_n_acquires_ok;
67atomic_t fscache_n_acquires_nobufs;
68atomic_t fscache_n_acquires_oom;
69
70atomic_t fscache_n_updates;
71atomic_t fscache_n_updates_null;
72atomic_t fscache_n_updates_run;
73
74atomic_t fscache_n_relinquishes;
75atomic_t fscache_n_relinquishes_null;
76atomic_t fscache_n_relinquishes_waitcrt;
77
78atomic_t fscache_n_cookie_index;
79atomic_t fscache_n_cookie_data;
80atomic_t fscache_n_cookie_special;
81
82atomic_t fscache_n_object_alloc;
83atomic_t fscache_n_object_no_alloc;
84atomic_t fscache_n_object_lookups;
85atomic_t fscache_n_object_lookups_negative;
86atomic_t fscache_n_object_lookups_positive;
87atomic_t fscache_n_object_created;
88atomic_t fscache_n_object_avail;
89atomic_t fscache_n_object_dead;
90
91atomic_t fscache_n_checkaux_none;
92atomic_t fscache_n_checkaux_okay;
93atomic_t fscache_n_checkaux_update;
94atomic_t fscache_n_checkaux_obsolete;
95
96/*
97 * display the general statistics
98 */
99static int fscache_stats_show(struct seq_file *m, void *v)
100{
101 seq_puts(m, "FS-Cache statistics\n");
102
103 seq_printf(m, "Cookies: idx=%u dat=%u spc=%u\n",
104 atomic_read(&fscache_n_cookie_index),
105 atomic_read(&fscache_n_cookie_data),
106 atomic_read(&fscache_n_cookie_special));
107
108 seq_printf(m, "Objects: alc=%u nal=%u avl=%u ded=%u\n",
109 atomic_read(&fscache_n_object_alloc),
110 atomic_read(&fscache_n_object_no_alloc),
111 atomic_read(&fscache_n_object_avail),
112 atomic_read(&fscache_n_object_dead));
113 seq_printf(m, "ChkAux : non=%u ok=%u upd=%u obs=%u\n",
114 atomic_read(&fscache_n_checkaux_none),
115 atomic_read(&fscache_n_checkaux_okay),
116 atomic_read(&fscache_n_checkaux_update),
117 atomic_read(&fscache_n_checkaux_obsolete));
118
119 seq_printf(m, "Pages : mrk=%u unc=%u\n",
120 atomic_read(&fscache_n_marks),
121 atomic_read(&fscache_n_uncaches));
122
123 seq_printf(m, "Acquire: n=%u nul=%u noc=%u ok=%u nbf=%u"
124 " oom=%u\n",
125 atomic_read(&fscache_n_acquires),
126 atomic_read(&fscache_n_acquires_null),
127 atomic_read(&fscache_n_acquires_no_cache),
128 atomic_read(&fscache_n_acquires_ok),
129 atomic_read(&fscache_n_acquires_nobufs),
130 atomic_read(&fscache_n_acquires_oom));
131
132 seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u\n",
133 atomic_read(&fscache_n_object_lookups),
134 atomic_read(&fscache_n_object_lookups_negative),
135 atomic_read(&fscache_n_object_lookups_positive),
136 atomic_read(&fscache_n_object_created));
137
138 seq_printf(m, "Updates: n=%u nul=%u run=%u\n",
139 atomic_read(&fscache_n_updates),
140 atomic_read(&fscache_n_updates_null),
141 atomic_read(&fscache_n_updates_run));
142
143 seq_printf(m, "Relinqs: n=%u nul=%u wcr=%u\n",
144 atomic_read(&fscache_n_relinquishes),
145 atomic_read(&fscache_n_relinquishes_null),
146 atomic_read(&fscache_n_relinquishes_waitcrt));
147
148 seq_printf(m, "AttrChg: n=%u ok=%u nbf=%u oom=%u run=%u\n",
149 atomic_read(&fscache_n_attr_changed),
150 atomic_read(&fscache_n_attr_changed_ok),
151 atomic_read(&fscache_n_attr_changed_nobufs),
152 atomic_read(&fscache_n_attr_changed_nomem),
153 atomic_read(&fscache_n_attr_changed_calls));
154
155 seq_printf(m, "Allocs : n=%u ok=%u wt=%u nbf=%u\n",
156 atomic_read(&fscache_n_allocs),
157 atomic_read(&fscache_n_allocs_ok),
158 atomic_read(&fscache_n_allocs_wait),
159 atomic_read(&fscache_n_allocs_nobufs));
160 seq_printf(m, "Allocs : ops=%u owt=%u\n",
161 atomic_read(&fscache_n_alloc_ops),
162 atomic_read(&fscache_n_alloc_op_waits));
163
164 seq_printf(m, "Retrvls: n=%u ok=%u wt=%u nod=%u nbf=%u"
165 " int=%u oom=%u\n",
166 atomic_read(&fscache_n_retrievals),
167 atomic_read(&fscache_n_retrievals_ok),
168 atomic_read(&fscache_n_retrievals_wait),
169 atomic_read(&fscache_n_retrievals_nodata),
170 atomic_read(&fscache_n_retrievals_nobufs),
171 atomic_read(&fscache_n_retrievals_intr),
172 atomic_read(&fscache_n_retrievals_nomem));
173 seq_printf(m, "Retrvls: ops=%u owt=%u\n",
174 atomic_read(&fscache_n_retrieval_ops),
175 atomic_read(&fscache_n_retrieval_op_waits));
176
177 seq_printf(m, "Stores : n=%u ok=%u agn=%u nbf=%u oom=%u\n",
178 atomic_read(&fscache_n_stores),
179 atomic_read(&fscache_n_stores_ok),
180 atomic_read(&fscache_n_stores_again),
181 atomic_read(&fscache_n_stores_nobufs),
182 atomic_read(&fscache_n_stores_oom));
183 seq_printf(m, "Stores : ops=%u run=%u\n",
184 atomic_read(&fscache_n_store_ops),
185 atomic_read(&fscache_n_store_calls));
186
187 seq_printf(m, "Ops : pend=%u run=%u enq=%u\n",
188 atomic_read(&fscache_n_op_pend),
189 atomic_read(&fscache_n_op_run),
190 atomic_read(&fscache_n_op_enqueue));
191 seq_printf(m, "Ops : dfr=%u rel=%u gc=%u\n",
192 atomic_read(&fscache_n_op_deferred_release),
193 atomic_read(&fscache_n_op_release),
194 atomic_read(&fscache_n_op_gc));
195 return 0;
196}
197
198/*
199 * open "/proc/fs/fscache/stats" allowing provision of a statistical summary
200 */
201static int fscache_stats_open(struct inode *inode, struct file *file)
202{
203 return single_open(file, fscache_stats_show, NULL);
204}
205
206const struct file_operations fscache_stats_fops = {
207 .owner = THIS_MODULE,
208 .open = fscache_stats_open,
209 .read = seq_read,
210 .llseek = seq_lseek,
211 .release = seq_release,
212};
generated by cgit v1.2.2 (git 2.25.0) at 2025-02-20 16:34:18 -0500