autofs_lookup(): hold ->d_lock over playing with ->d_flags

... as well as setting ->d_fsdata, etc.  Make all of that
atomic.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/autofs/root.c b/fs/autofs/root.c
index 64f974c61068a9bc6c1ad9d4ca5131c833ed6bc7..29abafc0ce31271c9684e83b383fca007198c669 100644 (file)
--- a/fs/autofs/root.c
+++ b/fs/autofs/root.c
@@ -504,21 +504,22 @@ static struct dentry *autofs_lookup(struct inode *dir,
                if (!autofs_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
                        return ERR_PTR(-ENOENT);
 
-               /* Mark entries in the root as mount triggers */
-               if (IS_ROOT(dentry->d_parent) &&
-                   autofs_type_indirect(sbi->type))
-                       __managed_dentry_set_managed(dentry);
-
                ino = autofs_new_ino(sbi);
                if (!ino)
                        return ERR_PTR(-ENOMEM);
 
+               spin_lock(&sbi->lookup_lock);
+               spin_lock(&dentry->d_lock);
+               /* Mark entries in the root as mount triggers */
+               if (IS_ROOT(dentry->d_parent) &&
+                   autofs_type_indirect(sbi->type))
+                       __managed_dentry_set_managed(dentry);
                dentry->d_fsdata = ino;
                ino->dentry = dentry;
 
-               spin_lock(&sbi->lookup_lock);
                list_add(&ino->active, &sbi->active_list);
                spin_unlock(&sbi->lookup_lock);
+               spin_unlock(&dentry->d_lock);
        }
        return NULL;
 }