--- /dev/null
+Add support for the uninit_groups feature to the kernel.
+
+Keep a high water mark of used inodes for each group to improve e2fsck time.
+Block and inode bitmaps can be uninitialized on disk via a flag in the
+group descriptor to avoid reading or scanning them at e2fsck time.
+A checksum of each group descriptor is used to ensure that corruption in
+the group descriptor's bit flags does not cause incorrect operation.
+
+Index: linux-2.6.18.8.orig/include/linux/ext3_fs.h
+===================================================================
+--- linux-2.6.18.8.orig.orig/include/linux/ext3_fs.h 2007-07-02 11:09:25.000000000 +0200
++++ linux-2.6.18.8.orig/include/linux/ext3_fs.h 2007-07-02 11:09:31.000000000 +0200
+@@ -150,16 +150,22 @@ struct ext3_allocation_request {
+ */
+ struct ext3_group_desc
+ {
+- __le32 bg_block_bitmap; /* Blocks bitmap block */
+- __le32 bg_inode_bitmap; /* Inodes bitmap block */
++ __le32 bg_block_bitmap; /* Blocks bitmap block */
++ __le32 bg_inode_bitmap; /* Inodes bitmap block */
+ __le32 bg_inode_table; /* Inodes table block */
+ __le16 bg_free_blocks_count; /* Free blocks count */
+ __le16 bg_free_inodes_count; /* Free inodes count */
+ __le16 bg_used_dirs_count; /* Directories count */
+- __u16 bg_pad;
+- __le32 bg_reserved[3];
++ __le16 bg_flags; /* EXT3_BG_flags (UNINIT, etc) */
++ __le32 bg_reserved[2]; /* Likely block/inode bitmap checksum */
++ __le16 bg_itable_unused; /* Unused inodes count */
++ __le16 bg_checksum; /* crc16(sb_uuid+group+desc) */
+ };
+
++#define EXT3_BG_INODE_UNINIT 0x0001 /* Inode table/bitmap not in use */
++#define EXT3_BG_BLOCK_UNINIT 0x0002 /* Block bitmap not in use */
++#define EXT3_BG_INODE_ZEROED 0x0004 /* On-disk itable initialized to zero */
++
+ /*
+ * Macro-instructions used to manage group descriptors
+ */
+@@ -603,6 +609,7 @@ static inline int ext3_valid_inum(struct
+ #define EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
+ #define EXT3_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
+ #define EXT3_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
++#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0010
+ #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK 0x0020
+
+ #define EXT3_FEATURE_INCOMPAT_COMPRESSION 0x0001
+@@ -619,6 +626,7 @@ static inline int ext3_valid_inum(struct
+ EXT3_FEATURE_INCOMPAT_EXTENTS)
+ #define EXT3_FEATURE_RO_COMPAT_SUPP (EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+ EXT3_FEATURE_RO_COMPAT_LARGE_FILE| \
++ EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
+ EXT3_FEATURE_RO_COMPAT_BTREE_DIR)
+
+Index: linux-2.6.18.8.orig/fs/ext3/resize.c
+===================================================================
+--- linux-2.6.18.8.orig.orig/fs/ext3/resize.c 2007-06-21 14:53:15.000000000 +0200
++++ linux-2.6.18.8.orig/fs/ext3/resize.c 2007-07-02 11:09:26.000000000 +0200
+@@ -18,6 +18,7 @@
+ #include <linux/errno.h>
+ #include <linux/slab.h>
+
++#include "group.h"
+
+ #define outside(b, first, last) ((b) < (first) || (b) >= (last))
+ #define inside(b, first, last) ((b) >= (first) && (b) < (last))
+@@ -822,6 +823,7 @@ int ext3_group_add(struct super_block *s
+ gdp->bg_inode_table = cpu_to_le32(input->inode_table);
+ gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
+ gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
++ gdp->bg_checksum = ext3_group_desc_csum(sbi, input->group, gdp);
+
+ /*
+ * Make the new blocks and inodes valid next. We do this before
+Index: linux-2.6.18.8.orig/fs/ext3/super.c
+===================================================================
+--- linux-2.6.18.8.orig.orig/fs/ext3/super.c 2007-07-02 11:09:26.000000000 +0200
++++ linux-2.6.18.8.orig/fs/ext3/super.c 2007-07-02 11:18:04.000000000 +0200
+@@ -41,6 +41,7 @@
+ #include "xattr.h"
+ #include "acl.h"
+ #include "namei.h"
++#include "group.h"
+
+ static int ext3_load_journal(struct super_block *, struct ext3_super_block *,
+ unsigned long journal_devnum);
+@@ -1225,6 +1226,91 @@ static int ext3_setup_super(struct super
+ return res;
+ }
+
++#if !defined(CONFIG_CRC16) && !defined(CONFIG_CRC16_MODULE)
++/** CRC table for the CRC-16. The poly is 0x8005 (x^16 + x^15 + x^2 + 1) */
++__u16 const crc16_table[256] = {
++ 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
++ 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
++ 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
++ 0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
++ 0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
++ 0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
++ 0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
++ 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
++ 0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
++ 0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
++ 0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
++ 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
++ 0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
++ 0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
++ 0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
++ 0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
++ 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
++ 0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
++ 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
++ 0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
++ 0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
++ 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
++ 0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
++ 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
++ 0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
++ 0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
++ 0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
++ 0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
++ 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
++ 0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
++ 0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
++ 0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
++};
++
++static inline __u16 crc16_byte(__u16 crc, const __u8 data)
++{
++ return (crc >> 8) ^ crc16_table[(crc ^ data) & 0xff];
++}
++
++__u16 crc16(__u16 crc, __u8 const *buffer, size_t len)
++{
++ while (len--)
++ crc = crc16_byte(crc, *buffer++);
++ return crc;
++}
++#endif
++
++__le16 ext3_group_desc_csum(struct ext3_sb_info *sbi, __u32 block_group,
++ struct ext3_group_desc *gdp)
++{
++ __u16 crc = 0;
++
++ if (sbi->s_es->s_feature_ro_compat &
++ cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
++ int offset = offsetof(struct ext3_group_desc, bg_checksum);
++ __le32 le_group = cpu_to_le32(block_group);
++
++ crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
++ crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
++ crc = crc16(crc, (__u8 *)gdp, offset);
++ offset += sizeof(gdp->bg_checksum); /* skip checksum */
++ BUG_ON(offset != sizeof(*gdp)); /* XXX handle s_desc_size */
++ /* for checksum of struct ext4_group_desc do the rest...
++ if ((sbi->s_es->s_feature_incompat &
++ cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
++ offset < le16_to_cpu(sbi->s_es->s_desc_size)) {
++ crc = crc16(crc, (__u8 *)gdp + offset,
++ le16_to_cpu(sbi->s_es->s_desc_size) -
++ offset);
++ */
++ }
++
++ return cpu_to_le16(crc);
++}
++
++int ext3_group_desc_csum_verify(struct ext3_sb_info *sbi, __u32 block_group,
++ struct ext3_group_desc *gdp)
++{
++ return (gdp->bg_checksum ==
++ ext3_group_desc_csum(sbi, block_group, gdp));
++}
++
+ /* Called at mount-time, super-block is locked */
+ static int ext3_check_descriptors (struct super_block * sb)
+ {
+@@ -1274,6 +1360,13 @@ static int ext3_check_descriptors (struc
+ le32_to_cpu(gdp->bg_inode_table));
+ return 0;
+ }
++ if (!ext3_group_desc_csum_verify(sbi, i, gdp)) {
++ ext3_error(sb, __FUNCTION__,
++ "Checksum for group %d failed (%u!=%u)\n", i,
++ le16_to_cpu(ext3_group_desc_csum(sbi,i,gdp)),
++ le16_to_cpu(gdp->bg_checksum));
++ return 0;
++ }
+ block += EXT3_BLOCKS_PER_GROUP(sb);
+ gdp++;
+ }
+Index: linux-2.6.18.8.orig/fs/ext3/group.h
+===================================================================
+--- /dev/null 1970-01-01 00:00:00.000000000 +0000
++++ linux-2.6.18.8.orig/fs/ext3/group.h 2007-07-02 11:09:26.000000000 +0200
+@@ -0,0 +1,29 @@
++/*
++ * linux/fs/ext3/group.h
++ *
++ * Copyright (C) 2007 Cluster File Systems, Inc
++ *
++ * Author: Andreas Dilger <adilger@clusterfs.com>
++ */
++
++#ifndef _LINUX_EXT3_GROUP_H
++#define _LINUX_EXT3_GROUP_H
++#if defined(CONFIG_CRC16) || defined(CONFIG_CRC16_MODULE)
++#include <linux/crc16.h>
++#endif
++
++extern __le16 ext3_group_desc_csum(struct ext3_sb_info *sbi, __u32 group,
++ struct ext3_group_desc *gdp);
++extern int ext3_group_desc_csum_verify(struct ext3_sb_info *sbi, __u32 group,
++ struct ext3_group_desc *gdp);
++struct buffer_head *read_block_bitmap(struct super_block *sb,
++ unsigned int block_group);
++extern unsigned ext3_init_block_bitmap(struct super_block *sb,
++ struct buffer_head *bh, int group,
++ struct ext3_group_desc *desc);
++#define ext3_free_blocks_after_init(sb, group, desc) \
++ ext3_init_block_bitmap(sb, NULL, group, desc)
++extern unsigned ext3_init_inode_bitmap(struct super_block *sb,
++ struct buffer_head *bh, int group,
++ struct ext3_group_desc *desc);
++#endif /* _LINUX_EXT3_GROUP_H */
+Index: linux-2.6.18.8.orig/fs/ext3/ialloc.c
+===================================================================
+--- linux-2.6.18.8.orig.orig/fs/ext3/ialloc.c 2007-07-02 11:09:26.000000000 +0200
++++ linux-2.6.18.8.orig/fs/ext3/ialloc.c 2007-07-02 11:19:43.000000000 +0200
+@@ -28,6 +28,7 @@
+
+ #include "xattr.h"
+ #include "acl.h"
++#include "group.h"
+
+ /*
+ * ialloc.c contains the inodes allocation and deallocation routines
+@@ -43,6 +44,52 @@
+ * the free blocks count in the block.
+ */
+
++/*
++ * To avoid calling the atomic setbit hundreds or thousands of times, we only
++ * need to use it within a single byte (to ensure we get endianness right).
++ * We can use memset for the rest of the bitmap as there are no other users.
++ */
++static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
++{
++ int i;
++
++ if (start_bit >= end_bit)
++ return;
++
++ ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
++ for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
++ ext3_set_bit(i, bitmap);
++ if (i < end_bit)
++ memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
++}
++
++/* Initializes an uninitialized inode bitmap */
++unsigned ext3_init_inode_bitmap(struct super_block *sb,
++ struct buffer_head *bh, int block_group,
++ struct ext3_group_desc *gdp)
++{
++ struct ext3_sb_info *sbi = EXT3_SB(sb);
++
++ J_ASSERT_BH(bh, buffer_locked(bh));
++
++ /* If checksum is bad mark all blocks and inodes used to prevent
++ * allocation, essentially implementing a per-group read-only flag. */
++ if (!ext3_group_desc_csum_verify(sbi, block_group, gdp)) {
++ ext3_error(sb, __FUNCTION__, "Checksum bad for group %u\n",
++ block_group);
++ gdp->bg_free_blocks_count = 0;
++ gdp->bg_free_inodes_count = 0;
++ gdp->bg_itable_unused = 0;
++ memset(bh->b_data, 0xff, sb->s_blocksize);
++ return 0;
++ }
++
++ memset(bh->b_data, 0, (EXT3_INODES_PER_GROUP(sb) + 7) / 8);
++ mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
++ bh->b_data);
++
++ return EXT3_INODES_PER_GROUP(sb);
++}
+
+ /*
+ * Read the inode allocation bitmap for a given block_group, reading
+@@ -59,8 +106,19 @@ read_inode_bitmap(struct super_block * s
+ desc = ext3_get_group_desc(sb, block_group, NULL);
+ if (!desc)
+ goto error_out;
+-
+- bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
++ if (desc->bg_flags & cpu_to_le16(EXT3_BG_INODE_UNINIT)) {
++ bh = sb_getblk(sb, le32_to_cpu(desc->bg_inode_bitmap));
++ if (!buffer_uptodate(bh)) {
++ lock_buffer(bh);
++ if (!buffer_uptodate(bh)) {
++ ext3_init_inode_bitmap(sb, bh,block_group,desc);
++ set_buffer_uptodate(bh);
++ }
++ unlock_buffer(bh);
++ }
++ } else {
++ bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
++ }
+ if (!bh)
+ ext3_error(sb, "read_inode_bitmap",
+ "Cannot read inode bitmap - "
+@@ -169,6 +227,8 @@ void ext3_free_inode (handle_t *handle,
+ if (is_directory)
+ gdp->bg_used_dirs_count = cpu_to_le16(
+ le16_to_cpu(gdp->bg_used_dirs_count) - 1);
++ gdp->bg_checksum = ext3_group_desc_csum(sbi,block_group,
++ gdp);
+ spin_unlock(sb_bgl_lock(sbi, block_group));
+ percpu_counter_inc(&sbi->s_freeinodes_counter);
+ if (is_directory)
+@@ -454,7 +514,7 @@ struct inode *ext3_new_inode(handle_t *h
+ struct ext3_sb_info *sbi;
+ int err = 0;
+ struct inode *ret;
+- int i;
++ int i, free = 0;
+
+ /* Cannot create files in a deleted directory */
+ if (!dir || !dir->i_nlink)
+@@ -571,11 +631,13 @@ repeat_in_this_group:
+ goto out;
+
+ got:
+- ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
+- if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
+- ext3_error (sb, "ext3_new_inode",
+- "reserved inode or inode > inodes count - "
+- "block_group = %d, inode=%lu", group, ino);
++ ino++;
++ if ((group == 0 && ino < EXT3_FIRST_INO(sb)) ||
++ ino > EXT3_INODES_PER_GROUP(sb)) {
++ ext3_error(sb, __FUNCTION__,
++ "reserved inode or inode > inodes count - "
++ "block_group = %d, inode=%lu", group,
++ ino + group * EXT3_INODES_PER_GROUP(sb));
+ err = -EIO;
+ goto fail;
+ }
+@@ -583,13 +645,64 @@ got:
+ BUFFER_TRACE(bh2, "get_write_access");
+ err = ext3_journal_get_write_access(handle, bh2);
+ if (err) goto fail;
++
++ /* We may have to initialize the block bitmap if it isn't already */
++ if (EXT3_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
++ gdp->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
++ struct buffer_head *block_bh = read_block_bitmap(sb, group);
++
++ BUFFER_TRACE(block_bh, "get block bitmap access");
++ err = ext3_journal_get_write_access(handle, block_bh);
++ if (err) {
++ brelse(block_bh);
++ goto fail;
++ }
++
++ free = 0;
++ spin_lock(sb_bgl_lock(sbi, group));
++ /* recheck and clear flag under lock if we still need to */
++ if (gdp->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
++ gdp->bg_flags &= cpu_to_le16(~EXT3_BG_BLOCK_UNINIT);
++ free = ext3_free_blocks_after_init(sb, group, gdp);
++ gdp->bg_free_blocks_count = cpu_to_le16(free);
++ }
++ spin_unlock(sb_bgl_lock(sbi, group));
++
++ /* Don't need to dirty bitmap block if we didn't change it */
++ if (free) {
++ BUFFER_TRACE(block_bh, "dirty block bitmap");
++ err = ext3_journal_dirty_metadata(handle, block_bh);
++ }
++
++ brelse(block_bh);
++ if (err)
++ goto fail;
++ }
++
+ spin_lock(sb_bgl_lock(sbi, group));
++ /* If we didn't allocate from within the initialized part of the inode
++ * table then we need to initialize up to this inode. */
++ if (EXT3_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
++ if (gdp->bg_flags & cpu_to_le16(EXT3_BG_INODE_UNINIT)) {
++ gdp->bg_flags &= cpu_to_le16(~EXT3_BG_INODE_UNINIT);
++ free = EXT3_INODES_PER_GROUP(sb);
++ } else {
++ free = EXT3_INODES_PER_GROUP(sb) -
++ le16_to_cpu(gdp->bg_itable_unused);
++ }
++
++ if (ino > free)
++ gdp->bg_itable_unused =
++ cpu_to_le16(EXT3_INODES_PER_GROUP(sb) - ino);
++ }
++
+ gdp->bg_free_inodes_count =
+ cpu_to_le16(le16_to_cpu(gdp->bg_free_inodes_count) - 1);
+ if (S_ISDIR(mode)) {
+ gdp->bg_used_dirs_count =
+ cpu_to_le16(le16_to_cpu(gdp->bg_used_dirs_count) + 1);
+ }
++ gdp->bg_checksum = ext3_group_desc_csum(sbi, group, gdp);
+ spin_unlock(sb_bgl_lock(sbi, group));
+ BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
+ err = ext3_journal_dirty_metadata(handle, bh2);
+@@ -611,7 +724,7 @@ got:
+ inode->i_gid = current->fsgid;
+ inode->i_mode = mode;
+
+- inode->i_ino = ino;
++ inode->i_ino = ino + group * EXT3_INODES_PER_GROUP(sb);
+ /* This is the optimal IO size (for stat), not the fs block size */
+ inode->i_blksize = PAGE_SIZE;
+ inode->i_blocks = 0;
+Index: linux-2.6.18.8.orig/fs/ext3/mballoc.c
+===================================================================
+--- linux-2.6.18.8.orig.orig/fs/ext3/mballoc.c 2007-07-02 11:09:25.000000000 +0200
++++ linux-2.6.18.8.orig/fs/ext3/mballoc.c 2007-07-02 11:09:26.000000000 +0200
+@@ -36,6 +36,8 @@
+ #include <linux/seq_file.h>
+ #include <linux/version.h>
+
++#include "group.h"
++
+ /*
+ * MUSTDO:
+ * - test ext3_ext_search_left() and ext3_ext_search_right()
+@@ -323,6 +325,7 @@ struct ext3_group_info {
+ unsigned long bb_state;
+ unsigned long bb_tid;
+ struct ext3_free_metadata *bb_md_cur;
++ struct ext3_group_desc *bb_gdp;
+ unsigned short bb_first_free;
+ unsigned short bb_free;
+ unsigned short bb_fragments;
+@@ -943,10 +946,7 @@ static int ext3_mb_init_cache(struct pag
+ if (first_group + i >= EXT3_SB(sb)->s_groups_count)
+ break;
+
+- err = -EIO;
+- desc = ext3_get_group_desc(sb, first_group + i, NULL);
+- if (desc == NULL)
+- goto out;
++ desc = EXT3_GROUP_INFO(sb, first_group + i)->bb_gdp;
+
+ err = -ENOMEM;
+ bh[i] = sb_getblk(sb, le32_to_cpu(desc->bg_block_bitmap));
+@@ -961,7 +961,12 @@ static int ext3_mb_init_cache(struct pag
+ unlock_buffer(bh[i]);
+ continue;
+ }
+-
++ if (desc->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
++ ext3_init_block_bitmap(sb, bh[i], first_group + i,desc);
++ set_buffer_uptodate(bh[i]);
++ unlock_buffer(bh[i]);
++ continue;
++ }
+ get_bh(bh[i]);
+ bh[i]->b_end_io = end_buffer_read_sync;
+ submit_bh(READ, bh[i]);
+@@ -1732,6 +1737,10 @@ static int ext3_mb_good_group(struct ext
+ switch (cr) {
+ case 0:
+ BUG_ON(ac->ac_2order == 0);
++ /* If this group is uninitialized, skip it initially */
++ if (grp->bb_gdp->bg_flags &
++ cpu_to_le16(EXT3_BG_BLOCK_UNINIT))
++ return 0;
+ bits = ac->ac_sb->s_blocksize_bits + 1;
+ for (i = ac->ac_2order; i <= bits; i++)
+ if (grp->bb_counters[i] > 0)
+@@ -1825,7 +1834,9 @@ repeat:
+ }
+
+ ac->ac_groups_scanned++;
+- if (cr == 0)
++ if (cr == 0 || (e3b.bd_info->bb_gdp->bg_flags &
++ cpu_to_le16(EXT3_BG_BLOCK_UNINIT) &&
++ ac->ac_2order != 0))
+ ext3_mb_simple_scan_group(ac, &e3b);
+ else if (cr == 1 && ac->ac_g_ex.fe_len == sbi->s_stripe)
+ ext3_mb_scan_aligned(ac, &e3b);
+@@ -2304,12 +2315,13 @@ int ext3_mb_init_backend(struct super_bl
+ i--;
+ goto err_freebuddy;
+ }
++ memset(meta_group_info[j], 0, len);
+ desc = ext3_get_group_desc(sb, i, NULL);
++ meta_group_info[j]->bb_gdp = desc;
+ if (desc == NULL) {
+ printk(KERN_ERR"EXT3-fs: can't read descriptor %u\n",i);
+ goto err_freebuddy;
+ }
+- memset(meta_group_info[j], 0, len);
+ set_bit(EXT3_GROUP_INFO_NEED_INIT_BIT,
+ &meta_group_info[j]->bb_state);
+
+@@ -2972,9 +2984,17 @@ int ext3_mb_mark_diskspace_used(struct e
+ mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len);
+
+ spin_lock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
++ if (gdp->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
++ gdp->bg_flags &= cpu_to_le16(~EXT3_BG_BLOCK_UNINIT);
++ gdp->bg_free_blocks_count =
++ cpu_to_le16(ext3_free_blocks_after_init(sb,
++ ac->ac_b_ex.fe_group,
++ gdp));
++ }
+ gdp->bg_free_blocks_count =
+ cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)
+ - ac->ac_b_ex.fe_len);
++ gdp->bg_checksum = ext3_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
+ spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
+ percpu_counter_mod(&sbi->s_freeblocks_counter, - ac->ac_b_ex.fe_len);
+
+@@ -4343,6 +4363,7 @@ do_more:
+ spin_lock(sb_bgl_lock(sbi, block_group));
+ gdp->bg_free_blocks_count =
+ cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) + count);
++ gdp->bg_checksum = ext3_group_desc_csum(sbi, block_group, gdp);
+ spin_unlock(sb_bgl_lock(sbi, block_group));
+ percpu_counter_mod(&sbi->s_freeblocks_counter, count);
+
+Index: linux-2.6.18.8.orig/fs/ext3/balloc.c
+===================================================================
+--- linux-2.6.18.8.orig.orig/fs/ext3/balloc.c 2007-07-02 11:09:25.000000000 +0200
++++ linux-2.6.18.8.orig/fs/ext3/balloc.c 2007-07-02 11:09:26.000000000 +0200
+@@ -20,6 +20,7 @@
+ #include <linux/quotaops.h>
+ #include <linux/buffer_head.h>
+
++#include "group.h"
+ /*
+ * balloc.c contains the blocks allocation and deallocation routines
+ */
+@@ -73,6 +74,75 @@ struct ext3_group_desc * ext3_get_group_
+ return desc + offset;
+ }
+
++/* Initializes an uninitialized block bitmap if given, and returns the
++ * number of blocks free in the group. */
++unsigned ext3_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
++ int block_group, struct ext3_group_desc *gdp)
++{
++ unsigned long start;
++ int bit, bit_max;
++ unsigned free_blocks;
++ struct ext3_sb_info *sbi = EXT3_SB(sb);
++
++ if (bh) {
++ J_ASSERT_BH(bh, buffer_locked(bh));
++
++ /* If checksum is bad mark all blocks use to prevent allocation,
++ * essentially implementing a per-group read-only flag. */
++ if (!ext3_group_desc_csum_verify(sbi, block_group, gdp)) {
++ ext3_error(sb, __FUNCTION__,
++ "Checksum bad for group %u\n", block_group);
++ gdp->bg_free_blocks_count = 0;
++ gdp->bg_free_inodes_count = 0;
++ gdp->bg_itable_unused = 0;
++ memset(bh->b_data, 0xff, sb->s_blocksize);
++ return 0;
++ }
++ memset(bh->b_data, 0, sb->s_blocksize);
++ }
++
++ /* Check for superblock and gdt backups in this group */
++ bit_max = ext3_bg_has_super(sb, block_group);
++
++ if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_META_BG) ||
++ block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
++ sbi->s_desc_per_block) {
++ if (bit_max) {
++ bit_max += ext3_bg_num_gdb(sb, block_group);
++ bit_max +=le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
++ }
++ } else { /* For META_BG_BLOCK_GROUPS */
++ int group_rel = (block_group -
++ le32_to_cpu(sbi->s_es->s_first_meta_bg)) %
++ EXT3_DESC_PER_BLOCK(sb);
++ if (group_rel == 0 || group_rel == 1 ||
++ (group_rel == EXT3_DESC_PER_BLOCK(sb) - 1))
++ bit_max += 1;
++ }
++
++ /* Last and first groups are always initialized */
++ free_blocks = EXT3_BLOCKS_PER_GROUP(sb) - bit_max;
++
++ if (bh) {
++ for (bit = 0; bit < bit_max; bit++)
++ ext3_set_bit(bit, bh->b_data);
++
++ start = block_group * EXT3_BLOCKS_PER_GROUP(sb) +
++ le32_to_cpu(sbi->s_es->s_first_data_block);
++
++ /* Set bits for block and inode bitmaps, and inode table */
++ ext3_set_bit(le32_to_cpu(gdp->bg_block_bitmap) - start,
++ bh->b_data);
++ ext3_set_bit(le32_to_cpu(gdp->bg_inode_bitmap) - start,
++ bh->b_data);
++ for (bit = le32_to_cpu(gdp->bg_inode_table) - start,
++ bit_max = bit + sbi->s_itb_per_group; bit < bit_max; bit++)
++ ext3_set_bit(bit, bh->b_data);
++ }
++
++ return free_blocks - sbi->s_itb_per_group - 2;
++}
++
+ /*
+ * Read the bitmap for a given block_group, reading into the specified
+ * slot in the superblock's bitmap cache.
+@@ -88,7 +158,19 @@ read_block_bitmap(struct super_block *sb
+ desc = ext3_get_group_desc (sb, block_group, NULL);
+ if (!desc)
+ goto error_out;
+- bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
++ if (desc->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
++ bh = sb_getblk(sb, le32_to_cpu(desc->bg_block_bitmap));
++ if (!buffer_uptodate(bh)) {
++ lock_buffer(bh);
++ if (!buffer_uptodate(bh)) {
++ ext3_init_block_bitmap(sb, bh,block_group,desc);
++ set_buffer_uptodate(bh);
++ }
++ unlock_buffer(bh);
++ }
++ } else {
++ bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
++ }
+ if (!bh)
+ ext3_error (sb, "read_block_bitmap",
+ "Cannot read block bitmap - "
+@@ -467,6 +549,7 @@ do_more:
+ desc->bg_free_blocks_count =
+ cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
+ group_freed);
++ desc->bg_checksum = ext3_group_desc_csum(sbi, block_group, desc);
+ spin_unlock(sb_bgl_lock(sbi, block_group));
+ percpu_counter_mod(&sbi->s_freeblocks_counter, count);
+
+@@ -1433,8 +1516,11 @@ allocated:
+ ret_block, goal_hits, goal_attempts);
+
+ spin_lock(sb_bgl_lock(sbi, group_no));
++ if (gdp->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT))
++ gdp->bg_flags &= cpu_to_le16(~EXT3_BG_BLOCK_UNINIT);
+ gdp->bg_free_blocks_count =
+ cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - num);
++ gdp->bg_checksum = ext3_group_desc_csum(sbi, group_no, gdp);
+ spin_unlock(sb_bgl_lock(sbi, group_no));
+ percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
+