autofs4: correct offset mount expire check

When checking a directory tree in autofs_tree_busy() we can incorrectly
decide that the tree isn't busy.  This happens for the case of an active
offset mount as autofs4_follow_mount() follows past the active offset
mount, which has an open file handle used for expires, causing the file
handle not to count toward the busyness check.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ian Kent 2008-11-06 12:53:22 -08:00 committed by Linus Torvalds
parent eefc488f96
commit bc9c406838

View File

@ -56,12 +56,23 @@ static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
mntget(mnt);
dget(dentry);
if (!autofs4_follow_mount(&mnt, &dentry))
if (!follow_down(&mnt, &dentry))
goto done;
/* This is an autofs submount, we can't expire it */
if (is_autofs4_dentry(dentry))
goto done;
if (is_autofs4_dentry(dentry)) {
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
/* This is an autofs submount, we can't expire it */
if (sbi->type == AUTOFS_TYPE_INDIRECT)
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(dentry))
goto done;
}
/* Update the expiry counter if fs is busy */
if (!may_umount_tree(mnt)) {