On 8.07.19 г. 15:01 ч., Stanislaw Gruszka wrote:

Upstream commit 38e3eebff643 ("btrfs: honor path->skip_locking in backref code") was incorrectly backported to 4.14.y . It misses removal of two lines from original commit, what cause deadlock.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203993 Reported-by: Olivier Mazouffre olivier.mazouffre@ims-bordeaux.fr Fixes: d819d97ea025 ("btrfs: honor path->skip_locking in backref code") Signed-off-by: Stanislaw Gruszka sgruszka@redhat.com

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I did not test the patch, not even compile, but backport looks obviously wrong compared to original commit.

I concur, it's indeed wrongly backported so:

Reviewed-by: Nikolay Borisov nborisov@suse.com

fs/btrfs/backref.c | 2 -- 1 file changed, 2 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index d826fbaf7d50..e4d5e6eae409 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1290,8 +1290,6 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans, ret = -EIO; goto out; }

• 		btrfs_tree_read_lock(eb);
  

• 		btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
  	if (!path->skip_locking) {
  		btrfs_tree_read_lock(eb);
  		btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);