NFS: Fix an rcu deadlock in nfs_delegation_find_inode()

I was able to reproduce this pretty regularily using xfstests generic/013 on NFS v4.0. Reported-by: Ross Zwisler <[email protected]> Fixes: 6c34265 (NFSv4: Return NFS4ERR_DELAY when a delegation recall fails due to igrab()) Signed-off-by: Anna Schumaker <[email protected]> Signed-off-by: Trond Myklebust <[email protected]>
zarubaf · Jun 14, 2018 · d5681f5 · d5681f5
1 parent 93b7f7a
commit d5681f5
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
@@ -883,8 +883,10 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 	rcu_read_lock();
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		res = nfs_delegation_find_inode_server(server, fhandle);
-		if (res != ERR_PTR(-ENOENT))
+		if (res != ERR_PTR(-ENOENT)) {
+			rcu_read_unlock();
 			return res;
+		}
 	}
 	rcu_read_unlock();
 	return ERR_PTR(-ENOENT);