In one of the error paths of nfs_path, it may return with dcache_lock still
held; fix this by adding and using a new error path Elong_unlock which unlocks
dcache_lock.
Signed-off-by: Josh Triplett <josh@freedesktop.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 
f4b90b43677fb23297c56802c3056fc304f988d9 commit)
                namelen = dentry->d_name.len;
                buflen -= namelen + 1;
                if (buflen < 0)
-                       goto Elong;
+                       goto Elong_unlock;
                end -= namelen;
                memcpy(end, dentry->d_name.name, namelen);
                *--end = '/';
        end -= namelen;
        memcpy(end, base, namelen);
        return end;
+Elong_unlock:
+       spin_unlock(&dcache_lock);
 Elong:
        return ERR_PTR(-ENAMETOOLONG);
 }