From ef778e7ae67cd426c30cad43378b908f5eb0bad5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 20 Dec 2012 21:52:36 +0000 Subject: FS-Cache: Provide proper invalidation Provide a proper invalidation method rather than relying on the netfs retiring the cookie it has and getting a new one. The problem with this is that isn't easy for the netfs to make sure that it has completed/cancelled all its outstanding storage and retrieval operations on the cookie it is retiring. Instead, have the cache provide an invalidation method that will cancel or wait for all currently outstanding operations before invalidating the cache, and will cause new operations to queue up behind that. Whilst invalidation is in progress, some requests will be rejected until the cache can stack a barrier on the operation queue to cause new operations to be deferred behind it. Signed-off-by: David Howells --- Documentation/filesystems/caching/backend-api.txt | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'Documentation/filesystems/caching/backend-api.txt') diff --git a/Documentation/filesystems/caching/backend-api.txt b/Documentation/filesystems/caching/backend-api.txt index f4769b9399d..d78bab9622c 100644 --- a/Documentation/filesystems/caching/backend-api.txt +++ b/Documentation/filesystems/caching/backend-api.txt @@ -308,6 +308,18 @@ performed on the denizens of the cache. These are held in a structure of type: obtained by calling object->cookie->def->get_aux()/get_attr(). + (*) Invalidate data object [mandatory]: + + int (*invalidate_object)(struct fscache_operation *op) + + This is called to invalidate a data object (as pointed to by op->object). + All the data stored for this object should be discarded and an + attr_changed operation should be performed. The caller will follow up + with an object update operation. + + fscache_op_complete() must be called on op before returning. + + (*) Discard object [mandatory]: void (*drop_object)(struct fscache_object *object) -- cgit v1.2.3-70-g09d2