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| author | David Howells <dhowells@redhat.com> | 2013-08-22 01:29:38 +0400 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2013-09-06 12:17:30 +0400 |
| commit | da9803bc8812f5bd3b26baaa90e515b843c65ff7 (patch) | |
| tree | 889b39ec88863fb46606cf345eeb4fdf8a90a67e /include/linux/fscache.h | |
| parent | 6e4664525b1db28f8c4e1130957f70a94c19213e (diff) | |
| download | linux-da9803bc8812f5bd3b26baaa90e515b843c65ff7.tar.xz | |
FS-Cache: Add interface to check consistency of a cached object
Extend the fscache netfs API so that the netfs can ask as to whether a cache
object is up to date with respect to its corresponding netfs object:
int fscache_check_consistency(struct fscache_cookie *cookie)
This will call back to the netfs to check whether the auxiliary data associated
with a cookie is correct. It returns 0 if it is and -ESTALE if it isn't; it
may also return -ENOMEM and -ERESTARTSYS.
The backends now have to implement a mandatory operation pointer:
int (*check_consistency)(struct fscache_object *object)
that corresponds to the above API call. FS-Cache takes care of pinning the
object and the cookie in memory and managing this call with respect to the
object state.
Original-author: Hongyi Jia <jiayisuse@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hongyi Jia <jiayisuse@gmail.com>
cc: Milosz Tanski <milosz@adfin.com>
Diffstat (limited to 'include/linux/fscache.h')
| -rw-r--r-- | include/linux/fscache.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/fscache.h b/include/linux/fscache.h index 7a086235da4b..d984aff32a11 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -183,6 +183,7 @@ extern struct fscache_cookie *__fscache_acquire_cookie( const struct fscache_cookie_def *, void *); extern void __fscache_relinquish_cookie(struct fscache_cookie *, int); +extern int __fscache_check_consistency(struct fscache_cookie *); extern void __fscache_update_cookie(struct fscache_cookie *); extern int __fscache_attr_changed(struct fscache_cookie *); extern void __fscache_invalidate(struct fscache_cookie *); @@ -326,6 +327,25 @@ void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) } /** + * fscache_check_consistency - Request that if the cache is updated + * @cookie: The cookie representing the cache object + * + * Request an consistency check from fscache, which passes the request + * to the backing cache. + * + * Returns 0 if consistent and -ESTALE if inconsistent. May also + * return -ENOMEM and -ERESTARTSYS. + */ +static inline +int fscache_check_consistency(struct fscache_cookie *cookie) +{ + if (fscache_cookie_valid(cookie)) + return __fscache_check_consistency(cookie); + else + return 0; +} + +/** * fscache_update_cookie - Request that a cache object be updated * @cookie: The cookie representing the cache object * |