FAILED: patch "[PATCH] nfs: clean up rest of reqs when failing to add one" failed to apply to 4.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c18b96a1b8629db8cf5ac9f8974ccb4abcc209ab Mon Sep 17 00:00:00 2001
From: Peng Tao <tao.peng@primarydata.com>
Date: Sat, 5 Dec 2015 01:59:56 +0800
Subject: [PATCH] nfs: clean up rest of reqs when failing to add one

If we fail to set up things before sending anything over wire,
we need to clean up the reqs that are still attached to the
IO descriptor.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 728f65884cea..13faa303eb3b 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1126,6 +1126,7 @@ static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
 static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
 		struct nfs_page *req)
 {
+	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 	int ret;
 
 	do {
@@ -1153,7 +1154,7 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
 
 	nfs_pageio_setup_mirroring(desc, req);
 	if (desc->pg_error < 0)
-		return 0;
+		goto out_failed;
 
 	for (midx = 0; midx < desc->pg_mirror_count; midx++) {
 		if (midx) {
@@ -1170,7 +1171,8 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
 
 			if (IS_ERR(dupreq)) {
 				nfs_page_group_unlock(req);
-				return 0;
+				desc->pg_error = PTR_ERR(dupreq);
+				goto out_failed;
 			}
 
 			nfs_lock_request(dupreq);
@@ -1183,10 +1185,19 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
 		if (nfs_pgio_has_mirroring(desc))
 			desc->pg_mirror_idx = midx;
 		if (!nfs_pageio_add_request_mirror(desc, dupreq))
-			return 0;
+			goto out_failed;
 	}
 
 	return 1;
+
+out_failed:
+	/*
+	 * We might have failed before sending any reqs over wire.
+	 * clean up rest of the reqs in mirror pg_list
+	 */
+	if (desc->pg_error)
+		desc->pg_completion_ops->error_cleanup(&mirror->pg_list);
+	return 0;
 }
 
 /*