[PATCH 2/2] erofs-utils: record sb_size instead of sb_extslots

[Gao Xiang]

Just follow the kernel implementation.

Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 dump/main.c              | 4 ++--
 include/erofs/internal.h | 7 ++++---
 lib/super.c              | 7 ++++++-
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/dump/main.c b/dump/main.c
index dd2c620..50f4662 100644
--- a/dump/main.c
+++ b/dump/main.c
@@ -654,8 +654,8 @@ static void erofsdump_show_superblock(void)
 		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 sb_size:                           %u\n",
+			sbi.sb_size | 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 46345e0..9fdff71 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -84,13 +84,14 @@ struct erofs_sb_info {
 
 	u32 feature_compat;
 	u32 feature_incompat;
-	u64 build_time;
-	u32 build_time_nsec;
 
-	u8  extslots;
 	unsigned char islotbits;
 	unsigned char blkszbits;
 
+	u32 sb_size;			/* total superblock size */
+	u32 build_time_nsec;
+	u64 build_time;
+
 	/* what we really care is nid, rather than ino.. */
 	erofs_nid_t root_nid;
 	/* used for statfs, f_files - f_favail */
diff --git a/lib/super.c b/lib/super.c
index f952f7e..4d16d29 100644
--- a/lib/super.c
+++ b/lib/super.c
@@ -104,6 +104,12 @@ int erofs_read_superblock(struct erofs_sb_info *sbi)
 		return ret;
 	}
 
+	sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
+	if (sbi->sb_size > (1 << sbi->blkszbits) - EROFS_SUPER_OFFSET) {
+		erofs_err("invalid sb_extslots %u (more than a fs block)",
+			  dsb->sb_extslots);
+		return -EINVAL;
+	}
 	sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
 	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
 	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
@@ -114,7 +120,6 @@ 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);
-- 
2.39.3