From ea2ae4958b1b7c4659c4e97446d614426031f54a Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 16 Jan 2020 12:17:45 +0800 Subject: [PATCH] btrfs: don't double lock the subvol_sem for rename exchange commit 943eb3bf25f4a7b745dd799e031be276aa104d82 upstream. 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: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- 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 7fd4458cf0a7..ebdb93b47ce7 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -9491,9 +9491,8 @@ 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); /* @@ -9727,9 +9726,8 @@ static int btrfs_rename_exchange(struct inode *old_dir, 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)); -- GitLab