[Ocfs2-devel] [PATCH 24/25] xfs: fix pagecache truncation prior to reflink

[Darrick J. Wong]

From: Darrick J. Wong <darrick.wong at oracle.com>

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.

Signed-off-by: Darrick J. Wong <darrick.wong at oracle.com>
---
 fs/xfs/xfs_reflink.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)


diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index ec09e2783afe..0f4678920240 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1328,8 +1328,9 @@ xfs_reflink_remap_prep(
 		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);
 
 	/*
 	 * Update inode timestamps and remove security privileges before we