[PATCH 2/2] erofs-utils: mkfs: correctly initialize `oci_cfg->layer_index`

[Yifan Zhao]

As a global variable, `oci_cfg->layer_index` is currently default
initialized to 0, which carries a specific semantic meaning.
Consequently, the current mkfs.erofs command only mistakenly constructs
layer 0 of the OCI image when invoked without explicitly specifying the
`layer=` option. Moreover, it becomes impossible to specify the image's
digest via the `blob=` option, erroneously resulting in EINVAL.

This patch addresses the issue by initializing `oci_cfg->layer_index`
to the invalid value -1.

Signed-off-by: Yifan Zhao <zhaoyifan28 at huawei.com>
---
 mkfs/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mkfs/main.c b/mkfs/main.c
index 5710948..22201d3 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -757,6 +757,8 @@ static int mkfs_parse_oci_options(struct ocierofs_config *oci_cfg, char *options
 	if (!options_str)
 		return 0;
 
+	oci_cfg->layer_index = -1;
+
 	opt = options_str;
 	q = strchr(opt, ',');
 	if (q)
-- 
2.43.0