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Subject[PATCH 20/28] FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure
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We must make sure that FSCACHE_COOKIE_LOOKING_UP is cleared on lookup failure
(if an object reaches the LC_DYING state), and we should clear it before
clearing FSCACHE_COOKIE_CREATING.

If this doesn't happen then fscache_wait_for_deferred_lookup() may hold
allocation and retrieval operations indefinitely until they're interrupted by
signals - which in turn pins the dying object until they go away.

Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fscache/object.c | 17 ++++++++++++-----
1 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 1a1afa8..74bc562 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -105,6 +105,7 @@ static inline void fscache_done_parent_op(struct fscache_object *object)
static void fscache_object_state_machine(struct fscache_object *object)
{
enum fscache_object_state new_state;
+ struct fscache_cookie *cookie;

ASSERT(object != NULL);

@@ -158,11 +159,17 @@ static void fscache_object_state_machine(struct fscache_object *object)

spin_lock(&object->lock);
object->state = FSCACHE_OBJECT_DYING;
- if (object->cookie &&
- test_and_clear_bit(FSCACHE_COOKIE_CREATING,
- &object->cookie->flags))
- wake_up_bit(&object->cookie->flags,
- FSCACHE_COOKIE_CREATING);
+ cookie = object->cookie;
+ if (cookie) {
+ if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP,
+ &cookie->flags))
+ wake_up_bit(&cookie->flags,
+ FSCACHE_COOKIE_LOOKING_UP);
+ if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
+ &cookie->flags))
+ wake_up_bit(&cookie->flags,
+ FSCACHE_COOKIE_CREATING);
+ }
spin_unlock(&object->lock);

fscache_done_parent_op(object);


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