ref: a207f1889d4ba00e5f069a876ab38cb8c7ea34d3
parent: 51f6da0b381c1598e84f12f2bf240e9e470d92b9
author: gkostka <kostka.grzegorz@gmail.com>
date: Sat Nov 8 09:16:23 EST 2014
meta_bg feature helper functions
--- a/lwext4/ext4_super.c
+++ b/lwext4/ext4_super.c
@@ -161,6 +161,81 @@
return true;
}
+static uint32_t ext4_bg_num_gdb_meta(struct ext4_sblock *s,
+ uint32_t group)
+{+ uint32_t dsc_per_block = ext4_sb_get_block_size(s) /
+ ext4_sb_get_desc_size(s);
+
+ uint32_t metagroup = group / dsc_per_block;
+ uint32_t first = metagroup * dsc_per_block;
+ uint32_t last = first + dsc_per_block - 1;
+
+ if (group == first || group == first + 1 || group == last)
+ return 1;
+ return 0;
+}
+
+static uint32_t ext4_bg_num_gdb_nometa(struct ext4_sblock *s,
+ uint32_t group)
+{+ if (!ext4_sb_is_super_in_bg(s, group))
+ return 0;
+ uint32_t dsc_per_block = ext4_sb_get_block_size(s) /
+ ext4_sb_get_desc_size(s);
+
+ uint32_t db_count = (ext4_block_group_cnt(s) + dsc_per_block - 1) /
+ dsc_per_block;
+
+
+ if (ext4_sb_has_feature_incompatible(s, EXT4_FEATURE_INCOMPAT_META_BG))
+ return ext4_sb_first_meta_bg(s);
+
+ return db_count;
+}
+
+uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group)
+{+ uint32_t dsc_per_block = ext4_sb_get_block_size(s) /
+ ext4_sb_get_desc_size(s);
+ uint32_t first_meta_bg = ext4_sb_first_meta_bg(s);
+ uint32_t metagroup = group / dsc_per_block;
+
+ if (!ext4_sb_has_feature_incompatible(s, EXT4_FEATURE_INCOMPAT_META_BG) ||
+ metagroup < first_meta_bg)
+ return ext4_bg_num_gdb_nometa(s, group);
+
+ return ext4_bg_num_gdb_meta(s, group);
+
+}
+
+uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,
+ uint32_t block_group)
+{+ uint32_t num;
+ uint32_t dsc_per_block = ext4_sb_get_block_size(s) /
+ ext4_sb_get_desc_size(s);
+
+
+ num = ext4_sb_is_super_in_bg(s, block_group);
+
+ if (!ext4_sb_has_feature_incompatible(s, EXT4_FEATURE_INCOMPAT_META_BG) ||
+ block_group < ext4_sb_first_meta_bg(s) *
+ dsc_per_block) {+ if (num) {+ num += ext4_bg_num_gdb(s, block_group);
+ num += ext4_get16(s, s_reserved_gdt_blocks);
+ }
+ } else {+ num += ext4_bg_num_gdb(s, block_group);
+ }
+
+ uint32_t clustersize = 1024 << ext4_get32(s, log_cluster_size);
+ uint32_t cluster_ratio = clustersize / ext4_sb_get_block_size(s);
+ uint32_t v = (num + cluster_ratio - 1) >> ext4_get32(s, log_cluster_size);
+
+ return v;
+}
/**
* @}
--- a/lwext4/ext4_super.h
+++ b/lwext4/ext4_super.h
@@ -210,6 +210,14 @@
* @return true if block group has superblock*/
bool ext4_sb_is_super_in_bg(struct ext4_sblock *s, uint32_t block_group);
+
+/**@brief TODO:*/
+uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group);
+
+/**@brief TODO:*/
+uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,
+ uint32_t block_group);
+
#endif /* EXT4_SUPER_H_ */
/**