diff options
| author | Filipe Manana <fdmanana@gmail.com> | 2014-03-14 20:55:01 +0000 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2014-03-20 17:15:28 -0700 |
| commit | 21543baddcdbaa49db5ac8766ae564381e7c64d9 (patch) | |
| tree | 4ce8aee02deb8ed2d37ef08fe7b2bf2ef66eec24 /fs/btrfs | |
| parent | c3a468915a384c0015263edd9b7263775599a323 (diff) | |
Btrfs: fix race when updating existing ref head
While we update an existing ref head's extent_op, we're not holding
its spinlock, so while we're updating its extent_op contents (key,
flags) we can have a task running __btrfs_run_delayed_refs() that
holds the ref head's lock and sets its extent_op to NULL right after
the task updating the ref head just checked its extent_op was not NULL.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/delayed-ref.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index 2502ba5a3ac0..31299646024d 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -495,6 +495,7 @@ update_existing_head_ref(struct btrfs_delayed_ref_node *existing, ref = btrfs_delayed_node_to_head(update); BUG_ON(existing_ref->is_data != ref->is_data); + spin_lock(&existing_ref->lock); if (ref->must_insert_reserved) { /* if the extent was freed and then * reallocated before the delayed ref @@ -536,7 +537,6 @@ update_existing_head_ref(struct btrfs_delayed_ref_node *existing, * only need the lock for this case cause we could be processing it * currently, for refs we just added we know we're a-ok. */ - spin_lock(&existing_ref->lock); existing->ref_mod += update->ref_mod; spin_unlock(&existing_ref->lock); } |