[PATCH 3/3] xfs: stop using set_blocksize

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

XFS has its own buffer cache for metadata that uses submit_bio, which
means that it no longer uses the block device pagecache for anything.
Create a more lightweight helper that runs the blocksize checks and
flushes dirty data and use that instead.  No more truncating the
pagecache because XFS does not use it or care about it.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/xfs/xfs_buf.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)


diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 1a2b3f06fa717e..5ae77ffdc947b1 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1719,18 +1719,25 @@ xfs_setsize_buftarg(
 	struct xfs_buftarg	*btp,
 	unsigned int		sectorsize)
 {
+	int			error;
+
 	/* Set up metadata sector size info */
 	btp->bt_meta_sectorsize = sectorsize;
 	btp->bt_meta_sectormask = sectorsize - 1;
 
-	if (set_blocksize(btp->bt_bdev_file, sectorsize)) {
+	error = bdev_validate_blocksize(btp->bt_bdev, sectorsize);
+	if (error) {
 		xfs_warn(btp->bt_mount,
-			"Cannot set_blocksize to %u on device %pg",
-			sectorsize, btp->bt_bdev);
+			"Cannot use blocksize %u on device %pg, err %d",
+			sectorsize, btp->bt_bdev, error);
 		return -EINVAL;
 	}
 
-	return 0;
+	/*
+	 * Flush the block device pagecache so our bios see anything dirtied
+	 * before mount.
+	 */
+	return sync_blockdev(btp->bt_bdev);
 }
 
 int