Commit 943eb3bf authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: don't double lock the subvol_sem for rename exchange

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: cdd1fedf

 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent db8fe64f
......@@ -9554,9 +9554,8 @@ static int btrfs_rename_exchange(struct inode *old_dir,
btrfs_init_log_ctx(&ctx_dest, new_inode);
/* close the race window with snapshot create/destroy ioctl */
if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
down_read(&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(&fs_info->subvol_sem);
/*
......@@ -9790,9 +9789,8 @@ out_fail:
ret = ret ? ret : ret2;
}
out_notrans:
if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
up_read(&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(&fs_info->subvol_sem);
ASSERT(list_empty(&ctx_root.list));
......
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