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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-nfs@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 117/371] NFS: Fix a soft lockup in the delegation recovery code
Date: Thu, 16 Jan 2020 12:19:49 -0500
Message-ID: <20200116172403.18149-60-sashal@kernel.org> (raw)
In-Reply-To: <20200116172403.18149-1-sashal@kernel.org>

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 6f9449be53f3ce383caed797708b332ede8d952c ]

Fix a soft lockup when NFS client delegation recovery is attempted
but the inode is in the process of being freed. When the
igrab(inode) call fails, and we have to restart the recovery process,
we need to ensure that we won't attempt to recover the same delegation
again.

Fixes: 45870d6909d5a ("NFSv4.1: Test delegation stateids when server...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/delegation.c | 20 ++++++++++++--------
 fs/nfs/delegation.h |  1 +
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 04d57e11577e..09b3bcb86d32 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -234,6 +234,8 @@ static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation
 	spin_lock(&delegation->lock);
 	if (delegation->inode != NULL)
 		inode = igrab(delegation->inode);
+	if (!inode)
+		set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
 	spin_unlock(&delegation->lock);
 	return inode;
 }
@@ -863,10 +865,11 @@ void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry_rcu(delegation, &server->delegations,
 								super_list) {
-			if (test_bit(NFS_DELEGATION_RETURNING,
-						&delegation->flags))
-				continue;
-			if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
+			if (test_bit(NFS_DELEGATION_INODE_FREEING,
+						&delegation->flags) ||
+			    test_bit(NFS_DELEGATION_RETURNING,
+						&delegation->flags) ||
+			    test_bit(NFS_DELEGATION_NEED_RECLAIM,
 						&delegation->flags) == 0)
 				continue;
 			if (!nfs_sb_active(server->super))
@@ -971,10 +974,11 @@ void nfs_reap_expired_delegations(struct nfs_client *clp)
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry_rcu(delegation, &server->delegations,
 								super_list) {
-			if (test_bit(NFS_DELEGATION_RETURNING,
-						&delegation->flags))
-				continue;
-			if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
+			if (test_bit(NFS_DELEGATION_INODE_FREEING,
+						&delegation->flags) ||
+			    test_bit(NFS_DELEGATION_RETURNING,
+						&delegation->flags) ||
+			    test_bit(NFS_DELEGATION_TEST_EXPIRED,
 						&delegation->flags) == 0)
 				continue;
 			if (!nfs_sb_active(server->super))
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index df41d16dc6ab..510c9edcc712 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -34,6 +34,7 @@ enum {
 	NFS_DELEGATION_RETURNING,
 	NFS_DELEGATION_REVOKED,
 	NFS_DELEGATION_TEST_EXPIRED,
+	NFS_DELEGATION_INODE_FREEING,
 };
 
 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
-- 
2.20.1


  parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116172403.18149-1-sashal@kernel.org>
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 114/371] fs/nfs: Fix nfs_parse_devname to not modify it's argument Sasha Levin
2020-01-16 17:19 ` Sasha Levin [this message]
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 121/371] NFS/pnfs: Bulk destroy of layouts needs to be safe w.r.t. umount Sasha Levin
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 127/371] NFSv4/flexfiles: Fix invalid deref in FF_LAYOUT_DEVID_NODE() Sasha Levin
2020-01-16 17:20 ` [PATCH AUTOSEL 4.14 172/371] NFS: Don't interrupt file writeout due to fatal errors Sasha Levin

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