[PATCH 5.4 77/84] NFSv4: Fix second deadlock in nfs4_evict_inode()

Greg Kroah-Hartman
2021-06-14T11:01:45Z

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

commit c3aba897c6e67fa464ec02b1f17911577d619713 upstream.

If the inode is being evicted but has to return a layout first, then
that too can cause a deadlock in the corner case where the server
reboots.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/nfs/nfs4proc.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9342,15 +9342,20 @@ int nfs4_proc_layoutreturn(struct nfs4_l
&task_setup_data.rpc_client, &msg);

dprintk("--> %s\n", __func__);
+ lrp->inode = nfs_igrab_and_active(lrp->args.inode);
if (!sync) {
- lrp->inode = nfs_igrab_and_active(lrp->args.inode);
if (!lrp->inode) {
nfs4_layoutreturn_release(lrp);
return -EAGAIN;
}
task_setup_data.flags |= RPC_TASK_ASYNC;
}
- nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1, 0);
+ if (!lrp->inode)
+ nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1,
+ 1);
+ else
+ nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1,
+ 0);
task = rpc_run_task(&task_setup_data);
if (IS_ERR(task))
return PTR_ERR(task);