Patch "SUNRPC: Lock the transport layer on shutdown" has been added to the 4.2-stable tree

[<gregkh@linuxfoundation.org>]

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

    SUNRPC: Lock the transport layer on shutdown

to the 4.2-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:
     sunrpc-lock-the-transport-layer-on-shutdown.patch
and it can be found in the queue-4.2 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 79234c3db6842a3de03817211d891e0c2878f756 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Fri, 18 Sep 2015 15:53:24 -0400
Subject: SUNRPC: Lock the transport layer on shutdown

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

commit 79234c3db6842a3de03817211d891e0c2878f756 upstream.

Avoid all races with the connect/disconnect handlers by taking the
transport lock.

Reported-by:"Suzuki K. Poulose" <suzuki.poulose@arm.com>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/sunrpc/xprt.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -614,6 +614,7 @@ static void xprt_autoclose(struct work_s
 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
 	xprt->ops->close(xprt);
 	xprt_release_write(xprt, NULL);
+	wake_up_bit(&xprt->state, XPRT_LOCKED);
 }
 
 /**
@@ -723,6 +724,7 @@ void xprt_unlock_connect(struct rpc_xprt
 	xprt->ops->release_xprt(xprt, NULL);
 out:
 	spin_unlock_bh(&xprt->transport_lock);
+	wake_up_bit(&xprt->state, XPRT_LOCKED);
 }
 
 /**
@@ -1394,6 +1396,10 @@ out:
 static void xprt_destroy(struct rpc_xprt *xprt)
 {
 	dprintk("RPC:       destroying transport %p\n", xprt);
+
+	/* Exclude transport connect/disconnect handlers */
+	wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_UNINTERRUPTIBLE);
+
 	del_timer_sync(&xprt->timer);
 
 	rpc_xprt_debugfs_unregister(xprt);


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

queue-4.2/nfs41-flexfiles-zero-out-ds-write-wcc.patch
queue-4.2/nfs-nfs_set_pgio_error-sometimes-misses-errors.patch
queue-4.2/nfs-fix-a-null-pointer-dereference-of-migration-recovery-ops-for-v4.2-client.patch
queue-4.2/sunrpc-xs_reset_transport-must-mark-the-connection-as-disconnected.patch
queue-4.2/nfs-fix-truncated-client-owner-id-without-proto-type.patch
queue-4.2/sunrpc-lock-the-transport-layer-on-shutdown.patch
queue-4.2/nfs-don-t-let-the-ctime-override-attribute-barriers.patch
queue-4.2/sunrpc-fix-a-thinko-in-xs_connect.patch
queue-4.2/nfsv4-don-t-set-setattr-for-o_rdonly-o_excl.patch
queue-4.2/nfs41-flexfiles-update-inode-after-write-finishes.patch
queue-4.2/nfsv4.1-pnfs-fix-borken-function-_same_data_server_addrs_locked.patch
queue-4.2/nfsv4-force-a-post-op-attribute-update-when-holding-a-delegation.patch
queue-4.2/nfsv4.1-pnfs-fix-atomicity-of-commit-list-updates.patch
queue-4.2/nfsv4.1-flexfiles-fix-a-protocol-error-in-layoutreturn.patch
queue-4.2/revert-nfsv4-remove-incorrect-check-in-can_open_delegated.patch
queue-4.2/sunrpc-ensure-that-we-wait-for-connections-to-complete-before-retrying.patch
queue-4.2/nfsv4.1-fix-a-protocol-issue-with-close-stateids.patch