From 6f9449be53f3ce383caed797708b332ede8d952c Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Thu, 21 Feb 2019 14:51:25 -0500
Subject: [PATCH] NFS: Fix a soft lockup in the delegation recovery code
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>
---
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 70e5931f3c604..2f6b447cdd825 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -229,6 +229,8 @@ 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;
}
@@ -944,10 +946,11 @@ 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))
@@ -1053,10 +1056,11 @@ 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 dcbf3394ba0e0..35b4b02c1ae01 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, const struct cred *cred,
--
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