[PATCH 2/2] erofs-utils: dump: print more superblock fields

[Gao Xiang]

From: Guo Xuenan <guoxuenan at huawei.com>

Let's print compression algorithms and sb_extslots as well as update
feature information for dump.erosf

The proposed superblock dump is shown as below:

Filesystem magic number:                      0xE0F5E1E2
Filesystem blocks:                            4624
Filesystem inode metadata start block:        0
Filesystem shared xattr metadata start block: 0
Filesystem root nid:                          37
Filesystem compr_algs:                        lz4, lz4hc, lzma
Filesystem sb_extslots:                       0
Filesystem inode count:                       6131
Filesystem created:                           Wed Jun  7 17:15:44 2023
Filesystem features:                          sb_csum mtime 0padding compr_cfgs big_pcluster
Filesystem UUID:                              not available

Signed-off-by: Guo Xuenan <guoxuenan at huawei.com>
Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 dump/main.c              | 29 +++++++++++++++++++++++++++++
 include/erofs/internal.h |  1 +
 lib/super.c              |  6 ++++++
 3 files changed, 36 insertions(+)

diff --git a/dump/main.c b/dump/main.c
index 409c851..7980f78 100644
--- a/dump/main.c
+++ b/dump/main.c
@@ -92,12 +92,14 @@ static struct erofsdump_feature feature_lists[] = {
 	{ true, EROFS_FEATURE_COMPAT_SB_CHKSUM, "sb_csum" },
 	{ true, EROFS_FEATURE_COMPAT_MTIME, "mtime" },
 	{ false, EROFS_FEATURE_INCOMPAT_ZERO_PADDING, "0padding" },
+	{ false, EROFS_FEATURE_INCOMPAT_COMPR_CFGS, "compr_cfgs" },
 	{ false, EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER, "big_pcluster" },
 	{ false, EROFS_FEATURE_INCOMPAT_CHUNKED_FILE, "chunked_file" },
 	{ false, EROFS_FEATURE_INCOMPAT_DEVICE_TABLE, "device_table" },
 	{ false, EROFS_FEATURE_INCOMPAT_ZTAILPACKING, "ztailpacking" },
 	{ false, EROFS_FEATURE_INCOMPAT_FRAGMENTS, "fragments" },
 	{ false, EROFS_FEATURE_INCOMPAT_DEDUPE, "dedupe" },
+	{ false, EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES, "xattr_prefixes" },
 };
 
 static int erofsdump_readdir(struct erofs_dir_context *ctx);
@@ -588,6 +590,23 @@ static void erofsdump_print_statistic(void)
 	erofsdump_filetype_distribution(file_types, OTHERFILETYPE);
 }
 
+static void erofsdump_print_supported_compressors(FILE *f, unsigned int mask)
+{
+	unsigned int i = 0;
+	bool comma = false;
+	const char *s;
+
+	while ((s = z_erofs_list_supported_algorithms(i++, &mask)) != NULL) {
+		if (*s == '\0')
+			continue;
+		if (comma)
+			fputs(", ", f);
+		fputs(s, f);
+		comma = true;
+	}
+	fputc('\n', f);
+}
+
 static void erofsdump_show_superblock(void)
 {
 	time_t time = sbi.build_time;
@@ -607,6 +626,16 @@ static void erofsdump_show_superblock(void)
 	if (erofs_sb_has_fragments(&sbi) && sbi.packed_nid > 0)
 		fprintf(stdout, "Filesystem packed nid:                        %llu\n",
 			sbi.packed_nid | 0ULL);
+	if (erofs_sb_has_compr_cfgs(&sbi)) {
+		fprintf(stdout, "Filesystem compr_algs:                        ");
+		erofsdump_print_supported_compressors(stdout,
+			sbi.available_compr_algs);
+	} else {
+		fprintf(stdout, "Filesystem lz4_max_distance:                  %u\n",
+			sbi.lz4_max_distance | 0U);
+	}
+	fprintf(stdout, "Filesystem sb_extslots:                       %u\n",
+			sbi.extslots | 0U);
 	fprintf(stdout, "Filesystem inode count:                       %llu\n",
 			sbi.inos | 0ULL);
 	fprintf(stdout, "Filesystem created:                           %s",
diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 04a9a69..a04e6a6 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -74,6 +74,7 @@ struct erofs_sb_info {
 	u64 build_time;
 	u32 build_time_nsec;
 
+	u8  extslots;
 	unsigned char islotbits;
 	unsigned char blkszbits;
 
diff --git a/lib/super.c b/lib/super.c
index 16a1d62..e8e84aa 100644
--- a/lib/super.c
+++ b/lib/super.c
@@ -106,11 +106,17 @@ int erofs_read_superblock(struct erofs_sb_info *sbi)
 	sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
 	sbi->inos = le64_to_cpu(dsb->inos);
 	sbi->checksum = le32_to_cpu(dsb->checksum);
+	sbi->extslots = dsb->sb_extslots;
 
 	sbi->build_time = le64_to_cpu(dsb->build_time);
 	sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
 
 	memcpy(&sbi->uuid, dsb->uuid, sizeof(dsb->uuid));
+
+	if (erofs_sb_has_compr_cfgs(sbi))
+		sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+	else
+		sbi->lz4_max_distance = le16_to_cpu(dsb->u1.lz4_max_distance);
 	return erofs_init_devices(sbi, dsb);
 }
 
-- 
2.24.4