From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 21 Oct 2019 18:12:13 +0000 (-0400)
Subject: NFSv4: Don't remove the delegation from the super_list more than once
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f9e0cc9c97906ede17ca5cd56a7b170830f4369a;p=linux.git

NFSv4: Don't remove the delegation from the super_list more than once

Add a check to ensure that we haven't already removed the delegation
from the inode after we take all the relevant locks.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 0c9339d559f5f..e80419a63fb5b 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -298,6 +298,10 @@ nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 		return NULL;
 
 	spin_lock(&delegation->lock);
+	if (!delegation->inode) {
+		spin_unlock(&delegation->lock);
+		return NULL;
+	}
 	set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 	list_del_rcu(&delegation->super_list);
 	delegation->inode = NULL;