[RFC PATCH v0 1/3] erofs-utils: add -C# for the maximum size of pclusters

[Gao Xiang via Linux-erofs <linux-erofs@lists.ozlabs.org>]

From: Gao Xiang <hsiangkao@aol.com>

Set up -C >= EROFS_BLKSIZ (more specifically, >= lclustersize)
to enable big pcluster feature.

Signed-off-by: Gao Xiang <hsiangkao@aol.com>
---
 include/erofs/config.h |  2 ++
 lib/config.c           |  1 +
 mkfs/main.c            | 14 +++++++++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/erofs/config.h b/include/erofs/config.h
index 02ddf594ca60..5f5a05a8b796 100644
--- a/include/erofs/config.h
+++ b/include/erofs/config.h
@@ -53,6 +53,8 @@ struct erofs_configure {
 	int c_force_inodeversion;
 	/* < 0, xattr disabled and INT_MAX, always use inline xattrs */
 	int c_inline_xattr_tolerance;
+
+	u32 c_physical_clusterblks;
 	u64 c_unix_timestamp;
 #ifdef WITH_ANDROID
 	char *mount_point;
diff --git a/lib/config.c b/lib/config.c
index 3ecd48140cfd..352a77c8d639 100644
--- a/lib/config.c
+++ b/lib/config.c
@@ -24,6 +24,7 @@ void erofs_init_configure(void)
 	cfg.c_force_inodeversion = 0;
 	cfg.c_inline_xattr_tolerance = 2;
 	cfg.c_unix_timestamp = -1;
+	cfg.c_physical_clusterblks = 1;
 }
 
 void erofs_show_config(void)
diff --git a/mkfs/main.c b/mkfs/main.c
index abd48be0fa4f..c4c67c962919 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -62,6 +62,7 @@ static void usage(void)
 	fputs("usage: [options] FILE DIRECTORY\n\n"
 	      "Generate erofs image from DIRECTORY to FILE, and [options] are:\n"
 	      " -zX[,Y]            X=compressor (Y=compression level, optional)\n"
+	      " -C#                specify the size of compress physical cluster in bytes\n"
 	      " -d#                set output message level to # (maximum 9)\n"
 	      " -x#                set xattr tolerance to # (< 0, disable xattrs; default 2)\n"
 	      " -EX[,...]          X=extended options\n"
@@ -152,7 +153,7 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
 	char *endptr;
 	int opt, i;
 
-	while((opt = getopt_long(argc, argv, "d:x:z:E:T:U:",
+	while((opt = getopt_long(argc, argv, "d:x:z:E:T:U:C:",
 				 long_options, NULL)) != -1) {
 		switch (opt) {
 		case 'z':
@@ -248,6 +249,17 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
 			cfg.fs_config_file = optarg;
 			break;
 #endif
+		case 'C':
+			i = strtoull(optarg, &endptr, 0);
+			if (*endptr != '\0' ||
+			    i < EROFS_BLKSIZ || i % EROFS_BLKSIZ) {
+				erofs_err("invalid physical clustersize %s",
+					  optarg);
+				return -EINVAL;
+			}
+			cfg.c_physical_clusterblks = i / EROFS_BLKSIZ;
+			break;
+
 		case 1:
 			usage();
 			exit(0);
-- 
2.24.0