autofs4: always use lookup for lookup

We need to be able to cope with the directory mutex being held during
->d_revalidate() in some cases, but not all cases, and not necessarily by
us.  Because we need to release the mutex when we call back to the daemon
to do perform a mount we must be sure that it is us who holds the mutex so
we must redirect mount requests to ->lookup() if the mutex is held.

Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Yehuda Saheh <yehuda@newdream.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index a796c9417fb..74bc9aa6df3 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -279,6 +279,7 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
                         root->d_mounted--;
                 }
                 ino->flags |= AUTOFS_INF_EXPIRING;
+                autofs4_add_expiring(root);
                 init_completion(&ino->expire_complete);
                 spin_unlock(&sbi->fs_lock);
                 return root;
@@ -406,6 +407,7 @@ found:
                 expired, (int)expired->d_name.len, expired->d_name.name);
         ino = autofs4_dentry_ino(expired);
         ino->flags |= AUTOFS_INF_EXPIRING;
+        autofs4_add_expiring(expired);
         init_completion(&ino->expire_complete);
         spin_unlock(&sbi->fs_lock);
         spin_lock(&dcache_lock);
@@ -433,7 +435,7 @@ int autofs4_expire_wait(struct dentry *dentry)
 
                 DPRINTK("expire done status=%d", status);
 
-                if (d_unhashed(dentry))
+                if (d_unhashed(dentry) && IS_DEADDIR(dentry->d_inode))
                         return -EAGAIN;
 
                 return status;
@@ -473,6 +475,7 @@ int autofs4_expire_run(struct super_block *sb,
         spin_lock(&sbi->fs_lock);
         ino = autofs4_dentry_ino(dentry);
         ino->flags &= ~AUTOFS_INF_EXPIRING;
+        autofs4_del_expiring(dentry);
         complete_all(&ino->expire_complete);
         spin_unlock(&sbi->fs_lock);
 
@@ -503,6 +506,7 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
                         ino->flags &= ~AUTOFS_INF_MOUNTPOINT;
                 }
                 ino->flags &= ~AUTOFS_INF_EXPIRING;
+                autofs4_del_expiring(dentry);
                 complete_all(&ino->expire_complete);
                 spin_unlock(&sbi->fs_lock);
                 dput(dentry);