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Commit 5a30d8a2 authored by David Howells's avatar David Howells Committed by Al Viro
Browse files

VFS: Fix automount for negative autofs dentries 



Autofs may set the DCACHE_NEED_AUTOMOUNT flag on negative dentries.  These
need attention from the automounter daemon regardless of the LOOKUP_FOLLOW flag.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarIan Kent <raven@themaw.net>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b4aff1f8

fs/namei.c

+15 −9
Original line number Diff line number Diff line
@@ -716,19 +716,25 @@ static int follow_automount(struct path *path, unsigned flags, 
	if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_PARENT))

		return -EISDIR; /* we actually want to stop here */



	/* We want to mount if someone is trying to open/create a file of any

	 * type under the mountpoint, wants to traverse through the mountpoint

	 * or wants to open the mounted directory.

	 *

	/*

	 * We don't want to mount if someone's just doing a stat and they've

	 * set AT_SYMLINK_NOFOLLOW - unless they're stat'ing a directory and

	 * appended a '/' to the name.

	 */

	if (!(flags & LOOKUP_FOLLOW) &&

	    !(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |

		       LOOKUP_OPEN | LOOKUP_CREATE)))

	if (!(flags & LOOKUP_FOLLOW)) {

		/* We do, however, want to mount if someone wants to open or

		 * create a file of any type under the mountpoint, wants to

		 * traverse through the mountpoint or wants to open the mounted

		 * directory.

		 * Also, autofs may mark negative dentries as being automount

		 * points.  These will need the attentions of the daemon to

		 * instantiate them before they can be used.

		 */

		if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |

			     LOOKUP_OPEN | LOOKUP_CREATE)) &&

		    path->dentry->d_inode)

			return -EISDIR;



	}

	current->total_link_count++;

	if (current->total_link_count >= 40)

		return -ELOOP;