Patch "NFSv4: Fix a hang in OPEN related to server reboot" has been added to the 4.11-stable tree

Patch "NFSv4: Fix a hang in OPEN related to server reboot" has been added to the 4.11-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    NFSv4: Fix a hang in OPEN related to server reboot

to the 4.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsv4-fix-a-hang-in-open-related-to-server-reboot.patch
and it can be found in the queue-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 56e0d71ef12f026d96213e45a662bde6bbff4676 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Sat, 15 Apr 2017 19:20:01 -0400
Subject: NFSv4: Fix a hang in OPEN related to server reboot

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

commit 56e0d71ef12f026d96213e45a662bde6bbff4676 upstream.

If the server fails to return the attributes as part of an OPEN
reply, and then reboots, we can end up hanging. The reason is that
the client attempts to send a GETATTR in order to pick up the
missing OPEN call, but fails to release the slot first, causing
reboot recovery to deadlock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: 2e80dbe7ac51a ("NFSv4.1: Close callback races for OPEN, LAYOUTGET...")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfs/nfs4proc.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2300,8 +2300,10 @@ static int _nfs4_proc_open(struct nfs4_o
 		if (status != 0)
 			return status;
 	}
-	if (!(o_res->f_attr->valid & NFS_ATTR_FATTR))
+	if (!(o_res->f_attr->valid & NFS_ATTR_FATTR)) {
+		nfs4_sequence_free_slot(&o_res->seq_res);
 		nfs4_proc_getattr(server, &o_res->fh, o_res->f_attr, o_res->f_label);
+	}
 	return 0;
 }
 


Patches currently in stable-queue which might be from trond.myklebust@primarydata.com are

queue-4.11/nfs-use-gfp_noio-for-two-allocations-in-writeback.patch
queue-4.11/nfsv4-fix-an-rcu-lock-leak.patch
queue-4.11/nfsv4-fix-a-hang-in-open-related-to-server-reboot.patch
queue-4.11/nfsd-fix-up-the-supattr_exclcreat-attributes.patch
queue-4.11/pnfs-flexfiles-check-the-result-of-nfs4_pnfs_ds_connect.patch
queue-4.11/nfs-fix-use-after-free-in-write-error-path.patch