Patch "NFS: Fix a write performance regression" 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

    NFS: Fix a write performance regression

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:
     nfs-fix-a-write-performance-regression.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 8fa4592a14ebb3c22a21d846d1e4f65dab7d1a7c Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Thu, 1 Oct 2015 18:38:27 -0400
Subject: NFS: Fix a write performance regression

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

commit 8fa4592a14ebb3c22a21d846d1e4f65dab7d1a7c upstream.

If all other conditions in nfs_can_extend_write() are met, and there
are no locks, then we should be able to assume close-to-open semantics
and the ability to extend our write to cover the whole page.

With this patch, the xfstests generic/074 test completes in 242s instead
of >1400s on my test rig.

Fixes: bd61e0a9c852 ("locks: convert posix locks to file_lock_context")
Cc: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfs/write.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1223,7 +1223,7 @@ static int nfs_can_extend_write(struct f
 		return 1;
 	if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
 		       list_empty_careful(&flctx->flc_posix)))
-		return 0;
+		return 1;
 
 	/* Check to see if there are whole file write locks */
 	ret = 0;


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

queue-4.2/nfs-fix-pg_test-page-count-calculation.patch
queue-4.2/nfs-do-cleanup-before-resetting-pageio-read-write-to-mds.patch
queue-4.2/nfs-fix-a-write-performance-regression.patch
queue-4.2/nfsv4-recovery-of-recalled-read-delegations-is-broken.patch
queue-4.2/nfs-fix-v4.2-seek-on-files-over-2-gigs.patch