[PATCH 4.19 070/243] xfs: extent shifting doesnt fully invalidate page cache

From: Greg Kroah-Hartman
Date: Wed Dec 11 2019 - 10:20:02 EST

From: Dave Chinner <dchinner@xxxxxxxxxx>

[ Upstream commit 7f9f71be84bcab368e58020a42f6d0dd97adf0ce ]

The extent shifting code uses a flush and invalidate mechainsm prior
to shifting extents around. This is similar to what
xfs_free_file_space() does, but it doesn't take into account things
like page cache vs block size differences, and it will fail if there
is a page that it currently busy.

xfs_flush_unmap_range() handles all of these cases, so just convert
xfs_prepare_shift() to us that mechanism rather than having it's own
special sauce.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
fs/xfs/xfs_bmap_util.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 41ad9eaab6ce9..c045723678be9 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1244,13 +1244,7 @@ xfs_prepare_shift(
* Writeback and invalidate cache for the remainder of the file as we're
* about to shift down every extent from offset to EOF.
- error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, offset, -1);
- if (error)
- return error;
- error = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
- offset >> PAGE_SHIFT, -1);
- if (error)
- return error;
+ error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));

* Clean out anything hanging around in the cow fork now that