Commit d4a85e35 authored by Ian Kent's avatar Ian Kent Committed by Al Viro
Browse files

autofs4 - fix autofs4_expire_indirect() traversal 



The vfs-scale changes changed the traversal used in
autofs4_expire_indirect() from a list to a depth first tree traversal
which isn't right.

Signed-off-by: default avatarIan Kent <raven@themaw.net>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f9398c23

fs/autofs4/expire.c

+51 −1
Original line number Diff line number Diff line
@@ -86,6 +86,56 @@ static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry) 
	return status;

}



/*

 * Calculate and dget next entry in the subdirs list under root.

 */

static struct dentry *get_next_positive_subdir(struct dentry *prev,

						struct dentry *root)

{

	struct list_head *next;

	struct dentry *p, *q;



	spin_lock(&autofs4_lock);



	if (prev == NULL) {

		spin_lock(&root->d_lock);

		prev = dget_dlock(root);

		next = prev->d_subdirs.next;

		p = prev;

		goto start;

	}



	p = prev;

	spin_lock(&p->d_lock);

again:

	next = p->d_u.d_child.next;

start:

	if (next == &root->d_subdirs) {

		spin_unlock(&p->d_lock);

		spin_unlock(&autofs4_lock);

		dput(prev);

		return NULL;

	}



	q = list_entry(next, struct dentry, d_u.d_child);



	spin_lock_nested(&q->d_lock, DENTRY_D_LOCK_NESTED);

	/* Negative dentry - try next */

	if (!simple_positive(q)) {

		spin_unlock(&p->d_lock);

		p = q;

		goto again;

	}

	dget_dlock(q);

	spin_unlock(&q->d_lock);

	spin_unlock(&p->d_lock);

	spin_unlock(&autofs4_lock);



	dput(prev);



	return q;

}



/*

 * Calculate and dget next entry in top down tree traversal.

 */
@@ -333,7 +383,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, 
	timeout = sbi->exp_timeout;



	dentry = NULL;

	while ((dentry = get_next_positive_dentry(dentry, root))) {

	while ((dentry = get_next_positive_subdir(dentry, root))) {

		spin_lock(&sbi->fs_lock);

		ino = autofs4_dentry_ino(dentry);

		/* No point expiring a pending mount */