FAILED: patch "[PATCH] NFSv4/pnfs: Fix a page lock leak in nfs_pageio_resend()" failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-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 f4340e9314dbfadc48758945f85fc3b16612d06f Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 12 Aug 2019 15:19:54 -0400
Subject: [PATCH] NFSv4/pnfs: Fix a page lock leak in nfs_pageio_resend()

If the attempt to resend the pages fails, we need to ensure that we
clean up those pages that were not transmitted.

Fixes: d600ad1f2bdb ("NFS41: pop some layoutget errors to application")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.5+

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index ed4e1b07447b..15c254753f88 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1251,20 +1251,22 @@ static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
 int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
 		      struct nfs_pgio_header *hdr)
 {
-	LIST_HEAD(failed);
+	LIST_HEAD(pages);
 
 	desc->pg_io_completion = hdr->io_completion;
 	desc->pg_dreq = hdr->dreq;
-	while (!list_empty(&hdr->pages)) {
-		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+	list_splice_init(&hdr->pages, &pages);
+	while (!list_empty(&pages)) {
+		struct nfs_page *req = nfs_list_entry(pages.next);
 
 		if (!nfs_pageio_add_request(desc, req))
-			nfs_list_move_request(req, &failed);
+			break;
 	}
 	nfs_pageio_complete(desc);
-	if (!list_empty(&failed)) {
-		list_move(&failed, &hdr->pages);
-		return desc->pg_error < 0 ? desc->pg_error : -EIO;
+	if (!list_empty(&pages)) {
+		int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
+		hdr->completion_ops->error_cleanup(&pages, err);
+		return err;
 	}
 	return 0;
 }