From: Tao Guo Subject: [PATCH] nfs: avoid possible deadlock bug when setting up delegation. Date: Thu, 20 May 2010 13:42:24 +0800 Message-ID: <20100520054216.GA27457@vmware> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "J. Bruce Fields" , Benny Halevy To: linux-nfs@vger.kernel.org Return-path: Received: from [221.122.61.232] ([221.122.61.232]:48633 "EHLO mx.bwstor.com.cn" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751498Ab0ETFnG (ORCPT ); Thu, 20 May 2010 01:43:06 -0400 Sender: linux-nfs-owner@vger.kernel.org List-ID: Unlock clp->cl_lock before taking inode->i_lock when setting up delegation to avoid possible deadlock bug. Signed-off-by: Tao Guo --- fs/nfs/delegation.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index ea61d26..0983930 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -233,6 +233,7 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct if (memcmp(&delegation->stateid, &old_delegation->stateid, sizeof(old_delegation->stateid)) == 0 && delegation->type == old_delegation->type) { + spin_unlock(&clp->cl_lock); goto out; } /* @@ -245,6 +246,7 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct if (delegation->type <= old_delegation->type) { freeme = delegation; delegation = NULL; + spin_unlock(&clp->cl_lock); goto out; } freeme = nfs_detach_delegation_locked(nfsi, NULL, clp); @@ -253,6 +255,7 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfsi->delegation_state = delegation->type; rcu_assign_pointer(nfsi->delegation, delegation); delegation = NULL; + spin_unlock(&clp->cl_lock); /* Ensure we revalidate the attributes and page cache! */ spin_lock(&inode->i_lock); @@ -260,7 +263,6 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct spin_unlock(&inode->i_lock); out: - spin_unlock(&clp->cl_lock); if (delegation != NULL) nfs_free_delegation(delegation); if (freeme != NULL) -- 1.6.3.3