[PATCH v3] erofs-utils: mkfs: Add volume-name setting support

[Naoto Yamaguchi]

The erofs_super_block has volume_name field.  On the other hand,
mkfs.erofs is not supporting to set volume name.
This patch add volume-name setting support to mkfs.erofs.
Option keyword is similar to mkfs.vfat.

usage:
  mkfs.erofs -L volume-label image-fn dir

Signed-off-by: Naoto Yamaguchi <naoto.yamaguchi at aisin.co.jp>
---
 include/erofs/internal.h |  1 +
 man/mkfs.erofs.1         |  5 +++++
 mkfs/main.c              | 13 ++++++++++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 2e0aae8..7dc42eb 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -92,6 +92,7 @@ struct erofs_sb_info {
 	u64 inos;
 
 	u8 uuid[16];
+	char volume_name[16];
 
 	u16 available_compr_algs;
 	u16 lz4_max_distance;
diff --git a/man/mkfs.erofs.1 b/man/mkfs.erofs.1
index 11e8323..b65d01b 100644
--- a/man/mkfs.erofs.1
+++ b/man/mkfs.erofs.1
@@ -66,6 +66,11 @@ Pack the tail part (pcluster) of compressed files into its metadata to save
 more space and the tail part I/O. (Linux v5.17+)
 .RE
 .TP
+.BI "\-L " volume-label
+Set the volume label for the filesystem to
+.IR volume-label .
+The maximum length of the volume label is 16 bytes.
+.TP
 .BI "\-T " #
 Set all files to the given UNIX timestamp. Reproducible builds requires setting
 all to a specific one.
diff --git a/mkfs/main.c b/mkfs/main.c
index 594ecf9..08a4215 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -84,6 +84,7 @@ static void usage(void)
 	      " -zX[,Y]               X=compressor (Y=compression level, optional)\n"
 	      " -C#                   specify the size of compress physical cluster in bytes\n"
 	      " -EX[,...]             X=extended options\n"
+	      " -L volume-label        set the volume label (max 16 bytes).\n"
 	      " -T#                   set a fixed UNIX timestamp # to all files\n"
 #ifdef HAVE_LIBUUID
 	      " -UX                   use a given filesystem UUID\n"
@@ -212,7 +213,7 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
 	int opt, i;
 	bool quiet = false;
 
-	while ((opt = getopt_long(argc, argv, "C:E:T:U:d:x:z:",
+	while ((opt = getopt_long(argc, argv, "C:E:L:T:U:d:x:z:",
 				  long_options, NULL)) != -1) {
 		switch (opt) {
 		case 'z':
@@ -255,6 +256,15 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
 			if (opt)
 				return opt;
 			break;
+
+		case 'L':
+			if (optarg == NULL || strlen(optarg) > 16) {
+				erofs_err("invalid volume label");
+				return -EINVAL;
+			}
+			strncpy(sbi.volume_name, optarg, 16);
+			break;
+
 		case 'T':
 			cfg.c_unix_timestamp = strtoull(optarg, &endptr, 0);
 			if (cfg.c_unix_timestamp == -1 || *endptr != '\0') {
@@ -483,6 +493,7 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh,
 	sb.blocks       = cpu_to_le32(*blocks);
 	sb.root_nid     = cpu_to_le16(root_nid);
 	memcpy(sb.uuid, sbi.uuid, sizeof(sb.uuid));
+	memcpy(sb.volume_name, sbi.volume_name, sizeof(sb.volume_name));
 
 	if (erofs_sb_has_compr_cfgs())
 		sb.u1.available_compr_algs = sbi.available_compr_algs;
-- 
2.25.1