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authorDavid Howells <dhowells@redhat.com>2009-11-19 18:11:22 +0000
committerDavid Howells <dhowells@redhat.com>2009-11-19 18:11:22 +0000
commit6897e3df8fc37bd4a58bbcdef8306da7fc175584 (patch)
treee826cd96f0395775d4fea113dc283ae0282f0384 /fs
parent5753c441889253e4323eee85f791a1d64cf08196 (diff)
FS-Cache: The object-available state can't rely on the cookie to be available
The object-available state in the object processing state machine (as processed by fscache_object_available()) can't rely on the cookie to be available because the FSCACHE_COOKIE_CREATING bit may have been cleared by fscache_obtained_object() prior to the object being put into the FSCACHE_OBJECT_AVAILABLE state. Clearing the FSCACHE_COOKIE_CREATING bit on a cookie permits __fscache_relinquish_cookie() to proceed and detach the cookie from the object. To deal with this, we don't dereference object->cookie in fscache_object_available() if the object has already been detached. In addition, a couple of assertions are added into fscache_drop_object() to make sure the object is unbound from the cookie before it gets there. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/fscache/object.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 0d65c0c92b4..1a1afa82f79 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -158,7 +158,8 @@ static void fscache_object_state_machine(struct fscache_object *object)
spin_lock(&object->lock);
object->state = FSCACHE_OBJECT_DYING;
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
+ if (object->cookie &&
+ test_and_clear_bit(FSCACHE_COOKIE_CREATING,
&object->cookie->flags))
wake_up_bit(&object->cookie->flags,
FSCACHE_COOKIE_CREATING);
@@ -594,7 +595,8 @@ static void fscache_object_available(struct fscache_object *object)
spin_lock(&object->lock);
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
+ if (object->cookie &&
+ test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING);
fscache_done_parent_op(object);
@@ -631,6 +633,9 @@ static void fscache_drop_object(struct fscache_object *object)
_enter("{OBJ%x,%d}", object->debug_id, object->n_children);
+ ASSERTCMP(object->cookie, ==, NULL);
+ ASSERT(hlist_unhashed(&object->cookie_link));
+
spin_lock(&cache->object_list_lock);
list_del_init(&object->cache_link);
spin_unlock(&cache->object_list_lock);