From 4918ef4ea008cd2ff47eb852894e3f9b9047f4f3 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Tue, 30 Oct 2018 10:46:33 +1100
Subject: [PATCH] xfs: fix pagecache truncation prior to reflink
Git-commit: 4918ef4ea008cd2ff47eb852894e3f9b9047f4f3
Patch-mainline: v4.20-rc1
References: bsc#1132412, bsc#1132219
Prior to remapping blocks, it is necessary to remove pages from the
destination file's page cache. Unfortunately, the truncation is not
aggressive enough -- if page size > block size, we'll end up zeroing
subpage blocks instead of removing them. So, round the start offset
down and the end offset up to page boundaries. We already wrote all
the dirty data so the larger range shouldn't be a problem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Acked-by: Anthony Iliopoulos <ailiopoulos@suse.com>
---
fs/xfs/xfs_reflink.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1432,8 +1432,9 @@
goto out_unlock;
/* Zap any page cache for the destination file's range. */
- truncate_inode_pages_range(&inode_out->i_data, pos_out,
- PAGE_ALIGN(pos_out + *len) - 1);
+ truncate_inode_pages_range(&inode_out->i_data,
+ round_down(pos_out, PAGE_SIZE),
+ round_up(pos_out + *len, PAGE_SIZE) - 1);
/* If we're altering the file contents... */
if (!is_dedupe) {