FS-Cache: Add cache tag handling
Implement two features of FS-Cache:
(1) The ability to request and release cache tags - names by which a cache may
be known to a netfs, and thus selected for use.
(2) An internal function by which a cache is selected by consulting the netfs,
if the netfs wishes to be consulted.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index feb3b0e..9584c09 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -173,6 +173,8 @@
* - these are undefined symbols when FS-Cache is not configured and the
* optimiser takes care of not using them
*/
+extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *);
+extern void __fscache_release_cache_tag(struct fscache_cache_tag *);
/**
* fscache_register_netfs - Register a filesystem as desiring caching services
@@ -218,7 +220,10 @@
static inline
struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name)
{
- return NULL;
+ if (fscache_available())
+ return __fscache_lookup_cache_tag(name);
+ else
+ return NULL;
}
/**
@@ -233,6 +238,8 @@
static inline
void fscache_release_cache_tag(struct fscache_cache_tag *tag)
{
+ if (fscache_available())
+ __fscache_release_cache_tag(tag);
}
/**