Patch "NFSv4.1: nfs4_fl_prepare_ds must be careful about reporting success." has been added to the 4.4-stable tree

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

NFSv4.1: nfs4_fl_prepare_ds must be careful about reporting success.

to the 4.4-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:
nfsv4.1-nfs4_fl_prepare_ds-must-be-careful-about-reporting-success.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: NeilBrown <[email protected]>
Date: Mon, 19 Dec 2016 11:19:31 +1100
Subject: NFSv4.1: nfs4_fl_prepare_ds must be careful about reporting success.

From: NeilBrown <[email protected]>

commit cfd278c280f997cf2fe4662e0acab0fe465f637b upstream.

Various places assume that if nfs4_fl_prepare_ds() turns a non-NULL 'ds', then ds->ds_clp will also be non-NULL.

This is not necessasrily true in the case when the process received a fatal signal while nfs4_pnfs_ds_connect is waiting in nfs4_wait_ds_connect().
In that case ->ds_clp may not be set, and the devid may not recently have been marked unavailable.

So add a test for ds_clp == NULL and return NULL in that case.

---
 fs/nfs/filelayout/filelayoutdev.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -283,7 +283,8 @@ nfs4_fl_prepare_ds(struct pnfs_layout_se
 			     s->nfs_client->cl_rpcclient->cl_auth->au_flavor);
 
 out_test_devid:
-	if (filelayout_test_devid_unavailable(devid))
+	if (ret->ds_clp == NULL ||
+	    filelayout_test_devid_unavailable(devid))
 		ret = NULL;
 out:
 	return ret;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/nfsv4.1-nfs4_fl_prepare_ds-must-be-careful-about-reporting-success.patch