CacheFiles: Implement interface to check cache consistency

Implement the FS-Cache interface to check the consistency of a cache object in
CacheFiles.

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>

1 files changed, 26 insertions, 0 deletions

diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index d4c1206af9fc..43eb5592cdea 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -378,6 +378,31 @@ static void cachefiles_sync_cache(struct fscache_cache *_cache)
 }
 
 /*
+ * check if the backing cache is updated to FS-Cache
+ * - called by FS-Cache when evaluates if need to invalidate the cache
+ */
+static bool cachefiles_check_consistency(struct fscache_operation *op)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        const struct cred *saved_cred;
+        int ret;
+
+        _enter("{OBJ%x}", op->object->debug_id);
+
+        object = container_of(op->object, struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        cachefiles_begin_secure(cache, &saved_cred);
+        ret = cachefiles_check_auxdata(object);
+        cachefiles_end_secure(cache, saved_cred);
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
  * notification the attributes on an object have changed
  * - called with reads/writes excluded by FS-Cache
  */
@@ -522,4 +547,5 @@ const struct fscache_cache_ops cachefiles_cache_ops = {
         .write_page             = cachefiles_write_page,
         .uncache_page           = cachefiles_uncache_page,
         .dissociate_pages       = cachefiles_dissociate_pages,
+        .check_consistency      = cachefiles_check_consistency,
 };