mnt: Don't propagate unmounts to locked mounts
authorEric W. Biederman <ebiederm@xmission.com>
Mon, 5 Jan 2015 19:38:04 +0000 (13:38 -0600)
committerEric W. Biederman <ebiederm@xmission.com>
Fri, 3 Apr 2015 01:34:20 +0000 (20:34 -0500)
commit0c56fe31420ca599c90240315f7959bf1b4eb6ce
tree6b61d7457c3ee31429e70ede1ebabb07e2bbebbb
parent5d88457eb5b86b475422dc882f089203faaeedb5
mnt: Don't propagate unmounts to locked mounts

If the first mount in shared subtree is locked don't unmount the
shared subtree.

This is ensured by walking through the mounts parents before children
and marking a mount as unmountable if it is not locked or it is locked
but it's parent is marked.

This allows recursive mount detach to propagate through a set of
mounts when unmounting them would not reveal what is under any locked
mount.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
fs/pnode.c
fs/pnode.h