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authorFilipe Manana <fdmanana@suse.com>2014-07-02 20:07:54 +0100
committerChris Mason <clm@fb.com>2014-08-15 07:43:13 -0700
commit6f7ff6d7832c6be13e8c95598884dbc40ad69fb7 (patch)
tree77cfeb9532c7eb15a9d6a1c880066e49e24a9e96
parente339a6b097c515a31ce230d498c44ff2e89f1cf4 (diff)
downloadlinux-6f7ff6d7832c6be13e8c95598884dbc40ad69fb7.tar.gz
Btrfs: read lock extent buffer while walking backrefs
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> Signed-off-by: Chris Mason <clm@fb.com>
-rw-r--r--fs/btrfs/backref.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index e25564bfcb4..a1efd39ca28 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;