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btrfs: unlock i_mutex after attempting to delete subvolume during send

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Whenever the check for a send in progress introduced in commit
521e0546c9 (btrfs: protect snapshots from deleting during send) is
hit, we return without unlocking inode->i_mutex. This is easy to see
with lockdep enabled:

[  +0.000059] ================================================
[  +0.000028] [ BUG: lock held when returning to user space! ]
[  +0.000029] 4.0.0-rc5-00096-g3c435c1 #93 Not tainted
[  +0.000026] ------------------------------------------------
[  +0.000029] btrfs/211 is leaving the kernel with locks still held!
[  +0.000029] 1 lock held by btrfs/211:
[  +0.000023]  #0:  (&type->i_mutex_dir_key){+.+.+.}, at: [<ffffffff8135b8df>] btrfs_ioctl_snap_destroy+0x2df/0x7a0

Make sure we unlock it in the error path.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Omar Sandoval 2015-04-10 14:20:40 -07:00 • committed by Chris Mason
parent b86054540e
commit 909e26dce3
1 changed files with 2 additions and 1 deletions
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3
fs/btrfs/ioctl.c
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@ -2410,7 +2410,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
"Attempt to delete subvolume %llu during send", "Attempt to delete subvolume %llu during send",
dest->root_key.objectid); dest->root_key.objectid);
err = -EPERM; err = -EPERM;
goto out_dput; goto out_unlock_inode;
} }
d_invalidate(dentry); d_invalidate(dentry);
@ -2505,6 +2505,7 @@ out_up_write:
root_flags & ~BTRFS_ROOT_SUBVOL_DEAD); root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
spin_unlock(&dest->root_item_lock); spin_unlock(&dest->root_item_lock);
} }
out_unlock_inode:
mutex_unlock(&inode->i_mutex); mutex_unlock(&inode->i_mutex);
if (!err) { if (!err) {
shrink_dcache_sb(root->fs_info->sb); shrink_dcache_sb(root->fs_info->sb);