btrfs: update comment and drop assertion in extent item lookup in find_parent_nodes()

Same comment was added to this type of error, unify that and drop the
assertion as we'd find out quickly that something is wrong after
returning -EUCLEAN.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index beed7e459dabde72cfa02ea7ab6e7f918f2c1229..0fa27ed802f6fb1819ce42e37b16f2de2873c109 100644 (file)
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1435,8 +1435,10 @@ again:
        if (ret < 0)
                goto out;
        if (ret == 0) {
-               /* This shouldn't happen, indicates a bug or fs corruption. */
-               ASSERT(ret != 0);
+               /*
+                * Key with offset -1 found, there would have to exist an extent
+                * item with such offset, but this is out of the valid range.
+                */
                ret = -EUCLEAN;
                goto out;
        }