From: Trond Myklebust Date: Thu, 22 Sep 2016 17:39:12 +0000 (-0400) Subject: NFSv4: Fix a race in nfs_inode_reclaim_delegation() X-Git-Tag: v4.9-rc2~13^2~21 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b1a318de9bc4946ad4a20481ab3ce28c2e8cd72c;p=platform%2Fkernel%2Flinux-amlogic.git NFSv4: Fix a race in nfs_inode_reclaim_delegation() If we race with a delegreturn before taking the spin lock, we currently end up dropping the delegation stateid. Signed-off-by: Trond Myklebust Tested-by: Oleg Drokin Signed-off-by: Anna Schumaker --- diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index 5de4cfb..094e0ef 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -195,15 +195,13 @@ void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, rcu_read_unlock(); put_rpccred(oldcred); trace_nfs4_reclaim_delegation(inode, res->delegation_type); - } else { - /* We appear to have raced with a delegation return. */ - spin_unlock(&delegation->lock); - rcu_read_unlock(); - nfs_inode_set_delegation(inode, cred, res); + return; } - } else { - rcu_read_unlock(); + /* We appear to have raced with a delegation return. */ + spin_unlock(&delegation->lock); } + rcu_read_unlock(); + nfs_inode_set_delegation(inode, cred, res); } static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)