commit f2de1d38d0819b17895977fabc52d81d0ea6ec00
author Valerie Clement <valerie.clement@bull.net> Thu Aug 30 17:38:13 2007 +0200
committer Theodore Ts'o <tytso@mit.edu> Sun Oct 14 22:08:35 2007 -0400
tree e42c37f4706fe45dc6ce96fb50cdd29b064ef677
parent 5d38ef1d049bf56d1c1e88b8b4d287c0f9470e61

libext2fs: Add EXT2_DESC_SIZE and EXT2_DESC_PER_BLOCK macros

Add macros to support variable-length group descriptors for ext4.

Signed-off-by: Valerie Clement <valerie.clement@bull.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

lib/ext2fs/closefs.c

diff --git a/lib/ext2fs/closefs.c b/lib/ext2fs/closefs.c
index 2086331..c8ef6ef 100644
--- a/lib/ext2fs/closefs.c
+++ b/lib/ext2fs/closefs.c
@@ -80,7 +80,7 @@
 		super_blk = group_block;
 		numblocks--;
 	}
-	meta_bg_size = (fs->blocksize / sizeof (struct ext2_group_desc));
+	meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 	meta_bg = group / meta_bg_size;
 
 	if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||

lib/ext2fs/ext2_fs.h

diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index a316665..36e7c8c 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -217,6 +217,13 @@
 /*
  * Macro-instructions used to manage group descriptors
  */
+#define EXT2_MIN_DESC_SIZE             32
+#define EXT2_MIN_DESC_SIZE_64BIT       64
+#define EXT2_MAX_DESC_SIZE             EXT2_MIN_BLOCK_SIZE
+#define EXT2_DESC_SIZE(s)                                                \
+       ((EXT2_SB(s)->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) ? \
+	(s)->s_desc_size : EXT2_MIN_DESC_SIZE)
+
 #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
 #define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
 #define EXT2_INODES_PER_BLOCK(s)	(EXT2_BLOCK_SIZE(s)/EXT2_INODE_SIZE(s))
@@ -227,7 +234,7 @@
 #define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
 #define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
 #else
-#define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
+#define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / EXT2_DESC_SIZE(s))
 #endif
 
 /*

lib/ext2fs/initialize.c

diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c
index 16e9eaa..a7f777b 100644
--- a/lib/ext2fs/initialize.c
+++ b/lib/ext2fs/initialize.c
@@ -67,7 +67,7 @@
 {
 	struct ext2_super_block *sb = fs->super;
 	unsigned long bpg = sb->s_blocks_per_group;
-	unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
+	unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
 	unsigned long max_blocks = 0xffffffff;
 	unsigned long rsv_groups;
 	unsigned int rsv_gdb;

lib/ext2fs/openfs.c

diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 2cc0336..0c38b17 100644
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -39,7 +39,7 @@
 	    (i < fs->super->s_first_meta_bg))
 		return (group_block + i + 1);
 
-	bg = (fs->blocksize / sizeof (struct ext2_group_desc)) * i;
+	bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
 	if (ext2fs_bg_has_super(fs, bg))
 		has_super = 1;
 	ret_blk = ext2fs_group_first_block(fs, bg) + has_super;
@@ -287,7 +287,7 @@
 	if (!group_block)
 		group_block = fs->super->s_first_data_block;
 	dest = (char *) fs->group_desc;
-	groups_per_block = fs->blocksize / sizeof(struct ext2_group_desc);
+	groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
 	for (i=0 ; i < fs->desc_blocks; i++) {
 		blk = ext2fs_descriptor_block_loc(fs, group_block, i);
 		retval = io_channel_read_blk(fs->io, blk, 1, dest);