1 /* FS-Cache interface to CacheFiles
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/slab.h>
13 #include <linux/mount.h>
16 struct cachefiles_lookup_data
{
17 struct cachefiles_xattr
*auxdata
; /* auxiliary data */
18 char *key
; /* key path */
21 static int cachefiles_attr_changed(struct fscache_object
*_object
);
24 * allocate an object record for a cookie lookup and prepare the lookup data
26 static struct fscache_object
*cachefiles_alloc_object(
27 struct fscache_cache
*_cache
,
28 struct fscache_cookie
*cookie
)
30 struct cachefiles_lookup_data
*lookup_data
;
31 struct cachefiles_object
*object
;
32 struct cachefiles_cache
*cache
;
33 struct cachefiles_xattr
*auxdata
;
34 unsigned keylen
, auxlen
;
38 cache
= container_of(_cache
, struct cachefiles_cache
, cache
);
40 _enter("{%s},%p,", cache
->cache
.identifier
, cookie
);
42 lookup_data
= kmalloc(sizeof(*lookup_data
), cachefiles_gfp
);
44 goto nomem_lookup_data
;
46 /* create a new object record and a temporary leaf image */
47 object
= kmem_cache_alloc(cachefiles_object_jar
, cachefiles_gfp
);
51 ASSERTCMP(object
->backer
, ==, NULL
);
53 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE
, &object
->flags
));
54 atomic_set(&object
->usage
, 1);
56 fscache_object_init(&object
->fscache
, cookie
, &cache
->cache
);
58 object
->type
= cookie
->def
->type
;
60 /* get hold of the raw key
61 * - stick the length on the front and leave space on the back for the
64 buffer
= kmalloc((2 + 512) + 3, cachefiles_gfp
);
68 keylen
= cookie
->def
->get_key(cookie
->netfs_data
, buffer
+ 2, 512);
69 ASSERTCMP(keylen
, <, 512);
71 *(uint16_t *)buffer
= keylen
;
72 ((char *)buffer
)[keylen
+ 2] = 0;
73 ((char *)buffer
)[keylen
+ 3] = 0;
74 ((char *)buffer
)[keylen
+ 4] = 0;
76 /* turn the raw key into something that can work with as a filename */
77 key
= cachefiles_cook_key(buffer
, keylen
+ 2, object
->type
);
81 /* get hold of the auxiliary data and prepend the object type */
84 if (cookie
->def
->get_aux
) {
85 auxlen
= cookie
->def
->get_aux(cookie
->netfs_data
,
87 ASSERTCMP(auxlen
, <, 511);
90 auxdata
->len
= auxlen
+ 1;
91 auxdata
->type
= cookie
->def
->type
;
93 lookup_data
->auxdata
= auxdata
;
94 lookup_data
->key
= key
;
95 object
->lookup_data
= lookup_data
;
97 _leave(" = %p [%p]", &object
->fscache
, lookup_data
);
98 return &object
->fscache
;
103 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE
, &object
->flags
));
104 kmem_cache_free(cachefiles_object_jar
, object
);
105 fscache_object_destroyed(&cache
->cache
);
109 _leave(" = -ENOMEM");
110 return ERR_PTR(-ENOMEM
);
114 * attempt to look up the nominated node in this cache
115 * - return -ETIMEDOUT to be scheduled again
117 static int cachefiles_lookup_object(struct fscache_object
*_object
)
119 struct cachefiles_lookup_data
*lookup_data
;
120 struct cachefiles_object
*parent
, *object
;
121 struct cachefiles_cache
*cache
;
122 const struct cred
*saved_cred
;
125 _enter("{OBJ%x}", _object
->debug_id
);
127 cache
= container_of(_object
->cache
, struct cachefiles_cache
, cache
);
128 parent
= container_of(_object
->parent
,
129 struct cachefiles_object
, fscache
);
130 object
= container_of(_object
, struct cachefiles_object
, fscache
);
131 lookup_data
= object
->lookup_data
;
133 ASSERTCMP(lookup_data
, !=, NULL
);
135 /* look up the key, creating any missing bits */
136 cachefiles_begin_secure(cache
, &saved_cred
);
137 ret
= cachefiles_walk_to_object(parent
, object
,
139 lookup_data
->auxdata
);
140 cachefiles_end_secure(cache
, saved_cred
);
142 /* polish off by setting the attributes of non-index files */
144 object
->fscache
.cookie
->def
->type
!= FSCACHE_COOKIE_TYPE_INDEX
)
145 cachefiles_attr_changed(&object
->fscache
);
147 if (ret
< 0 && ret
!= -ETIMEDOUT
) {
149 pr_warn("Lookup failed error %d\n", ret
);
150 fscache_object_lookup_error(&object
->fscache
);
153 _leave(" [%d]", ret
);
158 * indication of lookup completion
160 static void cachefiles_lookup_complete(struct fscache_object
*_object
)
162 struct cachefiles_object
*object
;
164 object
= container_of(_object
, struct cachefiles_object
, fscache
);
166 _enter("{OBJ%x,%p}", object
->fscache
.debug_id
, object
->lookup_data
);
168 if (object
->lookup_data
) {
169 kfree(object
->lookup_data
->key
);
170 kfree(object
->lookup_data
->auxdata
);
171 kfree(object
->lookup_data
);
172 object
->lookup_data
= NULL
;
177 * increment the usage count on an inode object (may fail if unmounting)
180 struct fscache_object
*cachefiles_grab_object(struct fscache_object
*_object
)
182 struct cachefiles_object
*object
=
183 container_of(_object
, struct cachefiles_object
, fscache
);
185 _enter("{OBJ%x,%d}", _object
->debug_id
, atomic_read(&object
->usage
));
187 #ifdef CACHEFILES_DEBUG_SLAB
188 ASSERT((atomic_read(&object
->usage
) & 0xffff0000) != 0x6b6b0000);
191 atomic_inc(&object
->usage
);
192 return &object
->fscache
;
196 * update the auxiliary data for an object object on disk
198 static void cachefiles_update_object(struct fscache_object
*_object
)
200 struct cachefiles_object
*object
;
201 struct cachefiles_xattr
*auxdata
;
202 struct cachefiles_cache
*cache
;
203 struct fscache_cookie
*cookie
;
204 const struct cred
*saved_cred
;
207 _enter("{OBJ%x}", _object
->debug_id
);
209 object
= container_of(_object
, struct cachefiles_object
, fscache
);
210 cache
= container_of(object
->fscache
.cache
, struct cachefiles_cache
,
213 if (!fscache_use_cookie(_object
)) {
218 cookie
= object
->fscache
.cookie
;
220 if (!cookie
->def
->get_aux
) {
221 fscache_unuse_cookie(_object
);
226 auxdata
= kmalloc(2 + 512 + 3, cachefiles_gfp
);
228 fscache_unuse_cookie(_object
);
233 auxlen
= cookie
->def
->get_aux(cookie
->netfs_data
, auxdata
->data
, 511);
234 fscache_unuse_cookie(_object
);
235 ASSERTCMP(auxlen
, <, 511);
237 auxdata
->len
= auxlen
+ 1;
238 auxdata
->type
= cookie
->def
->type
;
240 cachefiles_begin_secure(cache
, &saved_cred
);
241 cachefiles_update_object_xattr(object
, auxdata
);
242 cachefiles_end_secure(cache
, saved_cred
);
248 * discard the resources pinned by an object and effect retirement if
251 static void cachefiles_drop_object(struct fscache_object
*_object
)
253 struct cachefiles_object
*object
;
254 struct cachefiles_cache
*cache
;
255 const struct cred
*saved_cred
;
259 object
= container_of(_object
, struct cachefiles_object
, fscache
);
262 object
->fscache
.debug_id
, atomic_read(&object
->usage
));
264 cache
= container_of(object
->fscache
.cache
,
265 struct cachefiles_cache
, cache
);
267 #ifdef CACHEFILES_DEBUG_SLAB
268 ASSERT((atomic_read(&object
->usage
) & 0xffff0000) != 0x6b6b0000);
271 /* We need to tidy the object up if we did in fact manage to open it.
272 * It's possible for us to get here before the object is fully
273 * initialised if the parent goes away or the object gets retired
274 * before we set it up.
276 if (object
->dentry
) {
277 /* delete retired objects */
278 if (test_bit(FSCACHE_OBJECT_RETIRED
, &object
->fscache
.flags
) &&
279 _object
!= cache
->cache
.fsdef
281 _debug("- retire object OBJ%x", object
->fscache
.debug_id
);
282 cachefiles_begin_secure(cache
, &saved_cred
);
283 cachefiles_delete_object(cache
, object
);
284 cachefiles_end_secure(cache
, saved_cred
);
287 /* close the filesystem stuff attached to the object */
288 if (object
->backer
!= object
->dentry
)
289 dput(object
->backer
);
290 object
->backer
= NULL
;
293 /* note that the object is now inactive */
294 if (test_bit(CACHEFILES_OBJECT_ACTIVE
, &object
->flags
))
295 cachefiles_mark_object_inactive(cache
, object
);
297 dput(object
->dentry
);
298 object
->dentry
= NULL
;
304 * dispose of a reference to an object
306 static void cachefiles_put_object(struct fscache_object
*_object
)
308 struct cachefiles_object
*object
;
309 struct fscache_cache
*cache
;
313 object
= container_of(_object
, struct cachefiles_object
, fscache
);
316 object
->fscache
.debug_id
, atomic_read(&object
->usage
));
318 #ifdef CACHEFILES_DEBUG_SLAB
319 ASSERT((atomic_read(&object
->usage
) & 0xffff0000) != 0x6b6b0000);
322 ASSERTIFCMP(object
->fscache
.parent
,
323 object
->fscache
.parent
->n_children
, >, 0);
325 if (atomic_dec_and_test(&object
->usage
)) {
326 _debug("- kill object OBJ%x", object
->fscache
.debug_id
);
328 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE
, &object
->flags
));
329 ASSERTCMP(object
->fscache
.parent
, ==, NULL
);
330 ASSERTCMP(object
->backer
, ==, NULL
);
331 ASSERTCMP(object
->dentry
, ==, NULL
);
332 ASSERTCMP(object
->fscache
.n_ops
, ==, 0);
333 ASSERTCMP(object
->fscache
.n_children
, ==, 0);
335 if (object
->lookup_data
) {
336 kfree(object
->lookup_data
->key
);
337 kfree(object
->lookup_data
->auxdata
);
338 kfree(object
->lookup_data
);
339 object
->lookup_data
= NULL
;
342 cache
= object
->fscache
.cache
;
343 fscache_object_destroy(&object
->fscache
);
344 kmem_cache_free(cachefiles_object_jar
, object
);
345 fscache_object_destroyed(cache
);
354 static void cachefiles_sync_cache(struct fscache_cache
*_cache
)
356 struct cachefiles_cache
*cache
;
357 const struct cred
*saved_cred
;
360 _enter("%p", _cache
);
362 cache
= container_of(_cache
, struct cachefiles_cache
, cache
);
364 /* make sure all pages pinned by operations on behalf of the netfs are
366 cachefiles_begin_secure(cache
, &saved_cred
);
367 down_read(&cache
->mnt
->mnt_sb
->s_umount
);
368 ret
= sync_filesystem(cache
->mnt
->mnt_sb
);
369 up_read(&cache
->mnt
->mnt_sb
->s_umount
);
370 cachefiles_end_secure(cache
, saved_cred
);
373 cachefiles_io_error(cache
,
374 "Attempt to sync backing fs superblock"
375 " returned error %d",
380 * check if the backing cache is updated to FS-Cache
381 * - called by FS-Cache when evaluates if need to invalidate the cache
383 static bool cachefiles_check_consistency(struct fscache_operation
*op
)
385 struct cachefiles_object
*object
;
386 struct cachefiles_cache
*cache
;
387 const struct cred
*saved_cred
;
390 _enter("{OBJ%x}", op
->object
->debug_id
);
392 object
= container_of(op
->object
, struct cachefiles_object
, fscache
);
393 cache
= container_of(object
->fscache
.cache
,
394 struct cachefiles_cache
, cache
);
396 cachefiles_begin_secure(cache
, &saved_cred
);
397 ret
= cachefiles_check_auxdata(object
);
398 cachefiles_end_secure(cache
, saved_cred
);
400 _leave(" = %d", ret
);
405 * notification the attributes on an object have changed
406 * - called with reads/writes excluded by FS-Cache
408 static int cachefiles_attr_changed(struct fscache_object
*_object
)
410 struct cachefiles_object
*object
;
411 struct cachefiles_cache
*cache
;
412 const struct cred
*saved_cred
;
413 struct iattr newattrs
;
418 _object
->cookie
->def
->get_attr(_object
->cookie
->netfs_data
, &ni_size
);
420 _enter("{OBJ%x},[%llu]",
421 _object
->debug_id
, (unsigned long long) ni_size
);
423 object
= container_of(_object
, struct cachefiles_object
, fscache
);
424 cache
= container_of(object
->fscache
.cache
,
425 struct cachefiles_cache
, cache
);
427 if (ni_size
== object
->i_size
)
433 ASSERT(d_is_reg(object
->backer
));
435 fscache_set_store_limit(&object
->fscache
, ni_size
);
437 oi_size
= i_size_read(d_backing_inode(object
->backer
));
438 if (oi_size
== ni_size
)
441 cachefiles_begin_secure(cache
, &saved_cred
);
442 inode_lock(d_inode(object
->backer
));
444 /* if there's an extension to a partial page at the end of the backing
445 * file, we need to discard the partial page so that we pick up new
447 if (oi_size
& ~PAGE_MASK
&& ni_size
> oi_size
) {
448 _debug("discard tail %llx", oi_size
);
449 newattrs
.ia_valid
= ATTR_SIZE
;
450 newattrs
.ia_size
= oi_size
& PAGE_MASK
;
451 ret
= notify_change(object
->backer
, &newattrs
, NULL
);
453 goto truncate_failed
;
456 newattrs
.ia_valid
= ATTR_SIZE
;
457 newattrs
.ia_size
= ni_size
;
458 ret
= notify_change(object
->backer
, &newattrs
, NULL
);
461 inode_unlock(d_inode(object
->backer
));
462 cachefiles_end_secure(cache
, saved_cred
);
465 fscache_set_store_limit(&object
->fscache
, 0);
466 cachefiles_io_error_obj(object
, "Size set failed");
470 _leave(" = %d", ret
);
475 * Invalidate an object
477 static void cachefiles_invalidate_object(struct fscache_operation
*op
)
479 struct cachefiles_object
*object
;
480 struct cachefiles_cache
*cache
;
481 const struct cred
*saved_cred
;
486 object
= container_of(op
->object
, struct cachefiles_object
, fscache
);
487 cache
= container_of(object
->fscache
.cache
,
488 struct cachefiles_cache
, cache
);
490 op
->object
->cookie
->def
->get_attr(op
->object
->cookie
->netfs_data
,
493 _enter("{OBJ%x},[%llu]",
494 op
->object
->debug_id
, (unsigned long long)ni_size
);
496 if (object
->backer
) {
497 ASSERT(d_is_reg(object
->backer
));
499 fscache_set_store_limit(&object
->fscache
, ni_size
);
501 path
.dentry
= object
->backer
;
502 path
.mnt
= cache
->mnt
;
504 cachefiles_begin_secure(cache
, &saved_cred
);
505 ret
= vfs_truncate(&path
, 0);
507 ret
= vfs_truncate(&path
, ni_size
);
508 cachefiles_end_secure(cache
, saved_cred
);
511 fscache_set_store_limit(&object
->fscache
, 0);
513 cachefiles_io_error_obj(object
,
514 "Invalidate failed");
518 fscache_op_complete(op
, true);
523 * dissociate a cache from all the pages it was backing
525 static void cachefiles_dissociate_pages(struct fscache_cache
*cache
)
530 const struct fscache_cache_ops cachefiles_cache_ops
= {
531 .name
= "cachefiles",
532 .alloc_object
= cachefiles_alloc_object
,
533 .lookup_object
= cachefiles_lookup_object
,
534 .lookup_complete
= cachefiles_lookup_complete
,
535 .grab_object
= cachefiles_grab_object
,
536 .update_object
= cachefiles_update_object
,
537 .invalidate_object
= cachefiles_invalidate_object
,
538 .drop_object
= cachefiles_drop_object
,
539 .put_object
= cachefiles_put_object
,
540 .sync_cache
= cachefiles_sync_cache
,
541 .attr_changed
= cachefiles_attr_changed
,
542 .read_or_alloc_page
= cachefiles_read_or_alloc_page
,
543 .read_or_alloc_pages
= cachefiles_read_or_alloc_pages
,
544 .allocate_page
= cachefiles_allocate_page
,
545 .allocate_pages
= cachefiles_allocate_pages
,
546 .write_page
= cachefiles_write_page
,
547 .uncache_page
= cachefiles_uncache_page
,
548 .dissociate_pages
= cachefiles_dissociate_pages
,
549 .check_consistency
= cachefiles_check_consistency
,