[PATCH 1/2] mkfs: fix assertion failure on empty data file

[Zorro Lang <zlang@kernel.org>]

mkfs.xfs triggers an assertion failure, when it trys to make a xfs
on an empty file:
  # echo > emptyfile
  # mkfs.xfs emptyfile
  mkfs.xfs: xfs_mkfs.c:3852: validate_datadev: Assertion `cfg->dblocks' failed.
  Aborted                    (core dumped) mkfs.xfs emptyfile

This shouldn't be an assertion, but a warning.

Signed-off-by: Zorro Lang <zlang@kernel.org>
---
 mkfs/xfs_mkfs.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 527a662f..9a93330f 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3848,8 +3848,13 @@ validate_datadev(
 		if (!xi->data.isfile) {
 			fprintf(stderr, _("can't get size of data subvolume\n"));
 			usage();
+		} else {
+			if (!cli->dsize) {
+				fprintf(stderr,
+_("Warning: Empty file needs a data subvolume size by -d size=<value> option\n"));
+				usage();
+			}
 		}
-		ASSERT(cfg->dblocks);
 	} else if (cfg->dblocks) {
 		/* check the size fits into the underlying device */
 		if (cfg->dblocks > DTOBT(xi->data.size, cfg->blocklog)) {
-- 
2.52.0