[PATCH 042/115] autofs - remove autofs dentry mount check

[Luis Henriques]

3.5.7.13 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Jeffery <djeffery at redhat.com>

commit ce8a5dbdf9e709bdaf4618d7ef8cceb91e8adc69 upstream.

When checking if an autofs mount point is busy it isn't sufficient to
only check if it's a mount point.

For example, if the mount of an offset mountpoint in a tree is denied
for this host by its export and the dentry becomes a process working
directory the check incorrectly returns the mount as not in use at
expire.

This can happen since the default when mounting within a tree is
nostrict, which means ingnore mount fails on mounts within the tree and
continue.  The nostrict option is meant to allow mounting in this case.

Signed-off-by: David Jeffery <djeffery at redhat.com>
Signed-off-by: Ian Kent <raven at themaw.net>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/autofs4/expire.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 1feb68e..b1cdb0a 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -61,15 +61,6 @@ static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
 		/* This is an autofs submount, we can't expire it */
 		if (autofs_type_indirect(sbi->type))
 			goto done;
-
-		/*
-		 * Otherwise it's an offset mount and we need to check
-		 * if we can umount its mount, if there is one.
-		 */
-		if (!d_mountpoint(path.dentry)) {
-			status = 0;
-			goto done;
-		}
 	}
 
 	/* Update the expiry counter if fs is busy */
-- 
1.8.1.2