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author | David Howells <dhowells@redhat.com> | 2013-08-21 17:29:38 -0400 |
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committer | David Howells <dhowells@redhat.com> | 2013-09-06 09:17:30 +0100 |
commit | da9803bc8812f5bd3b26baaa90e515b843c65ff7 (patch) | |
tree | 889b39ec88863fb46606cf345eeb4fdf8a90a67e /Documentation/filesystems/caching/backend-api.txt | |
parent | 6e4664525b1db28f8c4e1130957f70a94c19213e (diff) | |
download | linux-da9803bc8812f5bd3b26baaa90e515b843c65ff7.tar.gz linux-da9803bc8812f5bd3b26baaa90e515b843c65ff7.tar.bz2 linux-da9803bc8812f5bd3b26baaa90e515b843c65ff7.zip |
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 'Documentation/filesystems/caching/backend-api.txt')
-rw-r--r-- | Documentation/filesystems/caching/backend-api.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/filesystems/caching/backend-api.txt b/Documentation/filesystems/caching/backend-api.txt index d78bab9622c6..277d1e810670 100644 --- a/Documentation/filesystems/caching/backend-api.txt +++ b/Documentation/filesystems/caching/backend-api.txt @@ -299,6 +299,15 @@ performed on the denizens of the cache. These are held in a structure of type: enough space in the cache to permit this. + (*) Check coherency state of an object [mandatory]: + + int (*check_consistency)(struct fscache_object *object) + + This method is called to have the cache check the saved auxiliary data of + the object against the netfs's idea of the state. 0 should be returned + if they're consistent and -ESTALE otherwise. -ENOMEM and -ERESTARTSYS + may also be returned. + (*) Update object [mandatory]: int (*update_object)(struct fscache_object *object) |