xfs: map unwritten blocks in XFS_IOC_{ALLOC,FREE}SP just like fallocate

mainline inclusion
from mainline-v5.16-rc5
commit 983d8e60
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4RCES
CVE: CVE-2021-4155

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=983d8e60f50806f90534cc5373d0ce867e5aaf79

--------------------------------

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: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NGuo Xuenan <guoxuenan@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/xfs/xfs_ioctl.c

@@ -686,7 +686,8 @@ 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;
 	}