[PATCH] autofs4: avoid panic on bind mount of autofs owned directory

While this is not a solution to bind and move mounts on autofs owned
directories it is necessary to fix the trady error handling.

At least it avoids the kernel panic I observed checking out bug #4589.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 4 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 500425e24fba..feb6ac427d05 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -56,12 +56,9 @@ static int autofs4_check_mount(struct vfsmount *mnt, struct dentry *dentry)
         mntget(mnt);
         dget(dentry);
 
-        if (!follow_down(&mnt, &dentry))
+        if (!autofs4_follow_mount(&mnt, &dentry))
                 goto done;
 
-        while (d_mountpoint(dentry) && follow_down(&mnt, &dentry))
-                ;
-
         /* This is an autofs submount, we can't expire it */
         if (is_autofs4_dentry(dentry))
                 goto done;