The patch below does not apply to the 5.4-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 3f015d89a47cd8855cd92f71fff770095bd885a1 Mon Sep 17 00:00:00 2001

From: Benjamin Coddington bcodding@redhat.com Date: Tue, 16 Nov 2021 10:48:13 -0500 Subject: [PATCH] NFSv42: Fix pagecache invalidation after COPY/CLONE

The mechanism in use to allow the client to see the results of COPY/CLONE is to drop those pages from the pagecache. This forces the client to read those pages once more from the server. However, truncate_pagecache_range() zeros out partial pages instead of dropping them. Let us instead use invalidate_inode_pages2_range() with full-page offsets to ensure the client properly sees the results of COPY/CLONE operations.

Cc: stable@vger.kernel.org # v4.7+ Fixes: 2e72448b07dc ("NFS: Add COPY nfs operation") Signed-off-by: Benjamin Coddington bcodding@redhat.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com

diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c index 08355b66e7cb..8b21ff1be717 100644 --- a/fs/nfs/nfs42proc.c +++ b/fs/nfs/nfs42proc.c @@ -289,7 +289,9 @@ static void nfs42_copy_dest_done(struct inode *inode, loff_t pos, loff_t len) loff_t newsize = pos + len; loff_t end = newsize - 1;

- truncate_pagecache_range(inode, pos, end); + WARN_ON_ONCE(invalidate_inode_pages2_range(inode->i_mapping, + pos >> PAGE_SHIFT, end >> PAGE_SHIFT)); + spin_lock(&inode->i_lock); if (newsize > i_size_read(inode)) i_size_write(inode, newsize);