diff mbox

Btrfs: read lock extent buffer while walking backrefs

Message ID 1404328074-3751-1-git-send-email-fdmanana@suse.com (mailing list archive)
State Accepted
Headers show

Commit Message

Filipe Manana July 2, 2014, 7:07 p.m. UTC 
Before processing the extent buffer, acquire a read lock on it, so
that we're safe against concurrent updates on the extent buffer.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/backref.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox

Patch

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index e25564b..a1efd39 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1001,8 +1001,11 @@  again:
 					ret = -EIO;
 					goto out;
 				}
+				btrfs_tree_read_lock(eb);
+				btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
 				ret = find_extent_in_eb(eb, bytenr,
 							*extent_item_pos, &eie);
+				btrfs_tree_read_unlock_blocking(eb);
 				free_extent_buffer(eb);
 				if (ret < 0)
 					goto out;