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Commit 9e3fea16 authored by Ian Kent's avatar Ian Kent Committed by Al Viro
Browse files

autofs4: Fix wait validation 



It is possible for the check in wait.c:validate_request() to return
an incorrect result if the dentry that was mounted upon has changed
during the callback.

Signed-off-by: default avatarIan Kent <raven@themaw.net>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 66511493

fs/autofs4/waitq.c

+16 −1
Original line number Diff line number Diff line
@@ -309,6 +309,9 @@ static int validate_request(struct autofs_wait_queue **wait, 
	 * completed while we waited on the mutex ...

	 */

	if (notify == NFY_MOUNT) {

		struct dentry *new = NULL;

		int valid = 1;



		/*

		 * If the dentry was successfully mounted while we slept

		 * on the wait queue mutex we can return success. If it
@@ -316,8 +319,20 @@ static int validate_request(struct autofs_wait_queue **wait, 
		 * a multi-mount with no mount at it's base) we can

		 * continue on and create a new request.

		 */

		if (!IS_ROOT(dentry)) {

			if (dentry->d_inode && d_unhashed(dentry)) {

				struct dentry *parent = dentry->d_parent;

				new = d_lookup(parent, &dentry->d_name);

				if (new)

					dentry = new;

			}

		}

		if (have_submounts(dentry))

			return 0;

			valid = 0;



		if (new)

			dput(new);

		return valid;

	}



	return 1;