diff options
| -rw-r--r-- | fs/btrfs/extent_io.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 3b9fb47..907ed00 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4184,6 +4184,7 @@ static inline void btrfs_release_extent_buffer(struct extent_buffer *eb) static void check_buffer_tree_ref(struct extent_buffer *eb) { + int refs; /* the ref bit is tricky. We have to make sure it is set * if we have the buffer dirty. Otherwise the * code to free a buffer can end up dropping a dirty @@ -4204,6 +4205,10 @@ static void check_buffer_tree_ref(struct extent_buffer *eb) * So bump the ref count first, then set the bit. If someone * beat us to it, drop the ref we added. */ + refs = atomic_read(&eb->refs); + if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) + return; + spin_lock(&eb->refs_lock); if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) atomic_inc(&eb->refs); @@ -4405,9 +4410,20 @@ static int release_extent_buffer(struct extent_buffer *eb, gfp_t mask) void free_extent_buffer(struct extent_buffer *eb) { + int refs; + int old; if (!eb) return; + while (1) { + refs = atomic_read(&eb->refs); + if (refs <= 3) + break; + old = atomic_cmpxchg(&eb->refs, refs, refs - 1); + if (old == refs) + return; + } + spin_lock(&eb->refs_lock); if (atomic_read(&eb->refs) == 2 && test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags)) |