diff mbox series

[24/26] xfs: fix pagecache truncation prior to reflink

Message ID 153966004854.3607.15187709452762502392.stgit@magnolia (mailing list archive)
State New, archived
Headers show
Series fs: fixes for serious clone/dedupe problems | expand

Commit Message

Darrick J. Wong Oct. 16, 2018, 3:20 a.m. UTC 
From: Darrick J. Wong <darrick.wong@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 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>
---
 fs/xfs/xfs_reflink.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Christoph Hellwig Oct. 17, 2018, 8:37 a.m. UTC | #1 
On Mon, Oct 15, 2018 at 08:20:48PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@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 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>

Looks fine,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 9b1ea42c81d1..e8e86646bb4b 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1369,8 +1369,9 @@  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);
 
 	return 1;
 out_unlock: