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| author | David Howells <[email protected]> | 2013-08-21 21:29:38 +0000 |
|---|---|---|
| committer | David Howells <[email protected]> | 2013-09-06 08:17:30 +0000 |
| commit | da9803bc8812f5bd3b26baaa90e515b843c65ff7 (patch) | |
| tree | 889b39ec88863fb46606cf345eeb4fdf8a90a67e /Documentation/filesystems/caching/netfs-api.txt | |
| parent | Linux 3.11 (diff) | |
| download | kernel-da9803bc8812f5bd3b26baaa90e515b843c65ff7.tar.gz kernel-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 <[email protected]>
Signed-off-by: David Howells <[email protected]>
cc: Hongyi Jia <[email protected]>
cc: Milosz Tanski <[email protected]>
Diffstat (limited to 'Documentation/filesystems/caching/netfs-api.txt')
| -rw-r--r-- | Documentation/filesystems/caching/netfs-api.txt | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/Documentation/filesystems/caching/netfs-api.txt b/Documentation/filesystems/caching/netfs-api.txt index 97e6c0ecc5ef..12b344251523 100644 --- a/Documentation/filesystems/caching/netfs-api.txt +++ b/Documentation/filesystems/caching/netfs-api.txt @@ -32,7 +32,7 @@ This document contains the following sections: (9) Setting the data file size (10) Page alloc/read/write (11) Page uncaching - (12) Index and data file update + (12) Index and data file consistency (13) Miscellaneous cookie operations (14) Cookie unregistration (15) Index invalidation @@ -690,9 +690,18 @@ written to the cache and for the cache to finish with the page generally. No error is returned. -========================== -INDEX AND DATA FILE UPDATE -========================== +=============================== +INDEX AND DATA FILE CONSISTENCY +=============================== + +To find out whether auxiliary data for an object is up to data within the +cache, the following function can be called: + + 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. To request an update of the index data for an index or other object, the following function should be called: |