From 85562d8aac9e5264514d6549ee0b6cac5640b0dc Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 19 Nov 2019 13:59:20 -0500 Subject: [PATCH] btrfs: don't double lock the subvol_sem for rename exchange [ Upstream commit 943eb3bf25f4a7b745dd799e031be276aa104d82 ] If we're rename exchanging two subvols we'll try to lock this lock twice, which is bad. Just lock once if either of the ino's are subvols. Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/inode.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 80937c5ca477..bb8863958ac0 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -9597,9 +9597,8 @@ static int btrfs_rename_exchange(struct inode *old_dir, return -EXDEV; /* close the race window with snapshot create/destroy ioctl */ - if (old_ino == BTRFS_FIRST_FREE_OBJECTID) - down_read(&root->fs_info->subvol_sem); - if (new_ino == BTRFS_FIRST_FREE_OBJECTID) + if (old_ino == BTRFS_FIRST_FREE_OBJECTID || + new_ino == BTRFS_FIRST_FREE_OBJECTID) down_read(&dest->fs_info->subvol_sem); /* @@ -9785,9 +9784,8 @@ out_fail: ret2 = btrfs_end_transaction(trans, root); ret = ret ? ret : ret2; out_notrans: - if (new_ino == BTRFS_FIRST_FREE_OBJECTID) - up_read(&dest->fs_info->subvol_sem); - if (old_ino == BTRFS_FIRST_FREE_OBJECTID) + if (new_ino == BTRFS_FIRST_FREE_OBJECTID || + old_ino == BTRFS_FIRST_FREE_OBJECTID) up_read(&root->fs_info->subvol_sem); return ret; -- 2.20.1