fuse: readdirplus: fix dentry leak

In case d_lookup() returns a dentry with d_inode == NULL, the dentry is not
returned with dput(). This results in triggering a BUG() in
shrink_dcache_for_umount_subtree():

  BUG: Dentry ...{i=0,n=...} still in use (1) [unmount of fuse fuse]

[SzM: need to d_drop() as well]

Reported-by: Justin Clift <jclift@redhat.com>
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Brian Foster <bfoster@redhat.com>
Tested-by: Niels de Vos <ndevos@redhat.com>
CC: stable@vger.kernel.org

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 0eda52738ec4d0fc6cac460fab9d4baddde4ff4b..2ae5308174e2938c49422c1fe08c1a316f642cfa 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1227,9 +1227,15 @@ static int fuse_direntplus_link(struct file *file,
 
        name.hash = full_name_hash(name.name, name.len);
        dentry = d_lookup(parent, &name);
-       if (dentry && dentry->d_inode) {
+       if (dentry) {
                inode = dentry->d_inode;
-               if (get_node_id(inode) == o->nodeid) {
+               if (!inode) {
+                       d_drop(dentry);
+               } else if (get_node_id(inode) != o->nodeid) {
+                       err = d_invalidate(dentry);
+                       if (err)
+                               goto out;
+               } else {
                        struct fuse_inode *fi;
                        fi = get_fuse_inode(inode);
                        spin_lock(&fc->lock);
@@ -1242,9 +1248,6 @@ static int fuse_direntplus_link(struct file *file,
                         */
                        goto found;
                }
-               err = d_invalidate(dentry);
-               if (err)
-                       goto out;
                dput(dentry);
                dentry = NULL;
        }