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| author | David Howells <dhowells@redhat.com> | 2009-11-19 21:11:22 +0300 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2009-11-19 21:11:22 +0300 |
| commit | 6897e3df8fc37bd4a58bbcdef8306da7fc175584 (patch) | |
| tree | e826cd96f0395775d4fea113dc283ae0282f0384 | |
| parent | 5753c441889253e4323eee85f791a1d64cf08196 (diff) | |
| download | linux-6897e3df8fc37bd4a58bbcdef8306da7fc175584.tar.xz | |
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>
| -rw-r--r-- | fs/fscache/object.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 0d65c0c92b46..1a1afa82f798 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); |