btrfs-progs: improve error messages after failed wiping

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/utils.c b/utils.c
index 77f0f68e..f22e3298 100644
--- a/utils.c
+++ b/utils.c
@@ -842,8 +842,11 @@ static int btrfs_wipe_existing_sb(int fd)
 
 	memset(buf, 0, len);
 	ret = pwrite(fd, buf, len, offset);
-	if (ret != len) {
-		fprintf(stderr, "ERROR: cannot wipe existing superblock\n");
+	if (ret < 0) {
+		error("cannot wipe existing superblock: %s", strerror(errno));
+		ret = -1;
+	} else if (ret != len) {
+		error("cannot wipe existing superblock: wrote %d of %zd", ret, len);
 		ret = -1;
 	}
 	fsync(fd);