From f106e82caaa0d943e47cacc184f5b40d538e0044 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 7 Dec 2010 01:51:26 +0000 Subject: [PATCH] Btrfs: Fix a crash when mounting a subvolume We should drop dentry before deactivating the superblock, otherwise we can hit this bug: BUG: Dentry f349a690{i=100,n=/} still in use (1) [unmount of btrfs loop1] ... Steps to reproduce the bug: # mount /dev/loop1 /mnt # mkdir save # btrfs subvolume snapshot /mnt save/snap1 # umount /mnt # mount -o subvol=save/snap1 /dev/loop1 /mnt (crash) Reported-by: Michael Niederle Signed-off-by: Li Zefan Signed-off-by: Chris Mason --- fs/btrfs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 47bf67cbe6bf..61bd79abb805 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -685,9 +685,9 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, mutex_unlock(&root->d_inode->i_mutex); if (IS_ERR(new_root)) { + dput(root); deactivate_locked_super(s); error = PTR_ERR(new_root); - dput(root); goto error_free_subvol_name; } if (!new_root->d_inode) {