From 983d8e60f50806f90534cc5373d0ce867e5aaf79 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Wed, 22 Dec 2021 14:19:18 -0800
Subject: [PATCH] xfs: map unwritten blocks in XFS_IOC_{ALLOC,FREE}SP just like
 fallocate

The old ALLOCSP/FREESP ioctls in XFS can be used to preallocate space at
the end of files, just like fallocate and RESVSP.  Make the behavior
consistent with the other ioctls.

Reported-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
---
 fs/xfs/xfs_ioctl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 174cd8950cb672..bc85e045845d13 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -687,7 +687,8 @@ xfs_ioc_space(
 
 	if (bf->l_start > XFS_ISIZE(ip)) {
 		error = xfs_alloc_file_space(ip, XFS_ISIZE(ip),
-				bf->l_start - XFS_ISIZE(ip), 0);
+				bf->l_start - XFS_ISIZE(ip),
+				XFS_BMAPI_PREALLOC);
 		if (error)
 			goto out_unlock;
 	}