[PATCH, E2FSPROGS] On-disk format definition group desciptor checksums

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Comments?

						- Ted


On-disk format definition for group descriptor checksums

- EXT4_FEATURE_RO_COMPAT_GDT_CSUM (0x0010?) - store a crc16 checksum in
  the group descriptor (s_uuid[16] | __u32 group | ext3_group_desc
  (excluding gd_checksum itself)).  This allows the kernel to more safely
  manage UNINIT groups.

Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>

Index: e2fsprogs/lib/ext2fs/ext2_fs.h
===================================================================
--- e2fsprogs.orig/lib/ext2fs/ext2_fs.h	2006-10-18 02:20:35.000000000 -0400
+++ e2fsprogs/lib/ext2fs/ext2_fs.h	2006-10-18 02:20:41.000000000 -0400
@@ -144,7 +144,9 @@
 	__u16	bg_free_inodes_count;	/* Free inodes count */
 	__u16	bg_used_dirs_count;	/* Directories count */
 	__u16	bg_flags;
-	__u32	bg_reserved[3];
+	__u32	bg_reserved[2];
+	__u16	bg_itable_unused;	/* Unused inodes count */
+	__u16	bg_checksum;		/* crc16(s_uuid+grouo_num+group_desc)*/
 };
 
 struct ext4_group_desc
@@ -601,6 +603,7 @@
 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
 /* #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004 not used */
 #define EXT4_FEATURE_RO_COMPAT_HUGE_FILE	0x0008
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
 
 #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
 #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
-
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