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: David Howells <dhowe...@redhat.com>
Acked-by: Ian Kent <ra...@themaw.net>
---

 fs/namei.c |   27 +++++++++++++++++++--------
 1 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 0223c41..93e221e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -777,18 +777,29 @@ static int follow_automount(struct path *path, unsigned 
flags,
        if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_CONTINUE))
                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
+       /* 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_CONTINUE | 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.
+                */
+               if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY |
+                            LOOKUP_OPEN | LOOKUP_CREATE))
+                       goto need_automount;
+
+               /* 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 (!path->dentry->d_inode)
+                       goto need_automount;
                return -EISDIR;
+       }
+need_automount:
 
        current->total_link_count++;
        if (current->total_link_count >= 40)

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