[PATCH 4.14 071/106] NFSv42: Fix pagecache invalidation after COPY/CLONE

Greg Kroah-Hartman
2021-12-06T15:17:25Z

From: Benjamin Coddington <bcodding@redhat.com>

commit 3f015d89a47cd8855cd92f71fff770095bd885a1 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/nfs/nfs42proc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -186,8 +186,9 @@ static ssize_t _nfs42_proc_copy(struct f
goto out;
}

- truncate_pagecache_range(dst_inode, pos_dst,
- pos_dst + res->write_res.count);
+ WARN_ON_ONCE(invalidate_inode_pages2_range(dst_inode->i_mapping,
+ pos_dst >> PAGE_SHIFT,
+ (pos_dst + res->write_res.count - 1) >> PAGE_SHIFT));

status = res->write_res.count;