uninitialized block groups

Index: linux-2.6.23-rc3/fs/ext4/balloc.c
===================================================================
@@ -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
  */

@@ -42,6 +43,75 @@ void ext4_get_group_no_and_offset(struct
 
 }
 
+/* Initializes an uninitialized block bitmap if given, and returns the
+ * number of blocks free in the group. */
+unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
+				int block_group, struct ext4_group_desc *gdp)
+{
+	unsigned long start;
+	int bit, bit_max;
+	unsigned free_blocks;
+	struct ext4_sb_info *sbi = EXT4_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 (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+			ext4_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 = ext4_bg_has_super(sb, block_group);
+
+	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_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 += ext4_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)) %
+				EXT4_DESC_PER_BLOCK(sb);
+		if (group_rel == 0 || group_rel == 1 ||
+		    (group_rel == EXT4_DESC_PER_BLOCK(sb) - 1))
+			bit_max += 1;
+	}
+
+	/* Last and first groups are always initialized */
+	free_blocks = EXT4_BLOCKS_PER_GROUP(sb) - bit_max;
+
+	if (bh) {
+		for (bit = 0; bit < bit_max; bit++)
+			ext4_set_bit(bit, bh->b_data);
+
+		start = block_group * EXT4_BLOCKS_PER_GROUP(sb) +
+			le32_to_cpu(sbi->s_es->s_first_data_block);
+
+		/* Set bits for block and inode bitmaps, and inode table */
+		ext4_set_bit(le32_to_cpu(gdp->bg_block_bitmap) - start,
+			     bh->b_data);
+		ext4_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++)
+			ext4_set_bit(bit, bh->b_data);
+	}
+
+	return free_blocks - sbi->s_itb_per_group - 2;
+}
+
 /*
  * The free blocks are managed by bitmaps.  A file system contains several
  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap

@@ -116,10 +186,22 @@ read_block_bitmap(struct super_block *sb
 	struct ext4_group_desc * desc;
 	struct buffer_head * bh = NULL;
 
-	desc = ext4_get_group_desc (sb, block_group, NULL);
+	desc = ext4_get_group_desc(sb, block_group, NULL);
 	if (!desc)
 		goto error_out;
-	bh = sb_bread(sb, ext4_block_bitmap(sb, desc));
+	if (desc->bg_flags & cpu_to_le16(EXT4_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)) {
+				ext4_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)
 		ext4_error (sb, "read_block_bitmap",
 			    "Cannot read block bitmap - "

@@ -588,6 +670,7 @@ do_more:
 	desc->bg_free_blocks_count =
 		cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
 			group_freed);
+	desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
 	spin_unlock(sb_bgl_lock(sbi, block_group));
 	percpu_counter_mod(&sbi->s_freeblocks_counter, count);
 

@@ -1656,8 +1739,11 @@ allocated:
 			ret_block, goal_hits, goal_attempts);
 
 	spin_lock(sb_bgl_lock(sbi, group_no));
+	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))
+		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 	gdp->bg_free_blocks_count =
 			cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
+	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
 	percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
 

Index: linux-2.6.23-rc3/fs/ext4/group.h
===================================================================
@@ -0,0 +1,29 @@
+/*
+ *  linux/fs/ext4/group.h
+ *
+ * Copyright (C) 2007 Cluster File Systems, Inc
+ *
+ * Author: Andreas Dilger <[email protected]>
+ */
+
+#ifndef _LINUX_EXT4_GROUP_H
+#define _LINUX_EXT4_GROUP_H
+#if defined(CONFIG_CRC16)
+#include <linux/crc16.h>
+#endif
+
+extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
+				   struct ext4_group_desc *gdp);
+extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
+				       struct ext4_group_desc *gdp);
+struct buffer_head *read_block_bitmap(struct super_block *sb,
+				      unsigned int block_group);
+extern unsigned ext4_init_block_bitmap(struct super_block *sb,
+				       struct buffer_head *bh, int group,
+				       struct ext4_group_desc *desc);
+#define ext4_free_blocks_after_init(sb, group, desc)			\
+		ext4_init_block_bitmap(sb, NULL, group, desc)
+extern unsigned ext4_init_inode_bitmap(struct super_block *sb,
+				       struct buffer_head *bh, int group,
+				       struct ext4_group_desc *desc);
+#endif /* _LINUX_EXT4_GROUP_H */

187 lines not on this page · raw message

Index: linux-2.6.23-rc3/fs/ext4/resize.c
===================================================================
@@ -16,6 +16,7 @@
 #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))

@@ -842,6 +843,7 @@ int ext4_group_add(struct super_block *s
 	ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
 	gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
 	gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb));
+	gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
 
 	/*
 	 * Make the new blocks and inodes valid next.  We do this before

114 lines not on this page · raw message

Index: linux-2.6.23-rc3/include/linux/ext4_fs.h
===================================================================
@@ -150,19 +150,25 @@ struct ext4_allocation_request {
  */
 struct ext4_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_flags;
-	__u32	bg_reserved[3];
+	__u32	bg_reserved[2];
+	__le16  bg_itable_unused;       /* Unused inodes count */
+	__le16  bg_checksum;            /* crc16(sb_uuid+group+desc) */
 	__le32	bg_block_bitmap_hi;	/* Blocks bitmap block MSB */
 	__le32	bg_inode_bitmap_hi;	/* Inodes bitmap block MSB */
 	__le32	bg_inode_table_hi;	/* Inodes table block MSB */
 };
 
+#define EXT4_BG_INODE_UNINIT  0x0001 /* Inode table/bitmap not in use */
+#define EXT4_BG_BLOCK_UNINIT  0x0002 /* Block bitmap not in use */
+#define EXT4_BG_INODE_ZEROED  0x0004 /* On-disk itable initialized to zero */
+
 #ifdef __KERNEL__
 #include <linux/ext4_fs_i.h>
 #include <linux/ext4_fs_sb.h>

@@ -734,6 +740,7 @@ static inline int ext4_valid_inum(struct
 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
 #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
 #define EXT4_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
 #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
 #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
 

@@ -755,6 +762,7 @@ static inline int ext4_valid_inum(struct
 					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
 					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \
 					 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \
+					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
 					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR)
 
 /*

Index: linux-2.6.23-rc4/fs/ext4/balloc.c
===================================================================
@@ -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
  */

@@ -42,6 +43,74 @@
 
 }
 
+/* Initializes an uninitialized block bitmap if given, and returns the
+ * number of blocks free in the group. */
+unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
+				int block_group, struct ext4_group_desc *gdp)
+{
+	unsigned long start;
+	int bit, bit_max;
+	unsigned free_blocks;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (bh) {
+		J_ASSERT_BH(bh, buffer_locked(bh));
+
+		/* If checksum is bad mark all blocks used to prevent allocation
+		 * essentially implementing a per-group read-only flag. */
+		if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+			ext4_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 = ext4_bg_has_super(sb, block_group);
+
+	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_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 += ext4_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)) %
+				EXT4_DESC_PER_BLOCK(sb);
+		if (group_rel == 0 || group_rel == 1 ||
+		    (group_rel == EXT4_DESC_PER_BLOCK(sb) - 1))
+			bit_max += 1;
+	}
+
+	/* Last and first groups are always initialized */
+	free_blocks = EXT4_BLOCKS_PER_GROUP(sb) - bit_max;
+
+	if (bh) {
+		for (bit = 0; bit < bit_max; bit++)
+			ext4_set_bit(bit, bh->b_data);
+
+		start = block_group * EXT4_BLOCKS_PER_GROUP(sb) +
+			le32_to_cpu(sbi->s_es->s_first_data_block);
+
+		/* Set bits for block and inode bitmaps, and inode table */
+		ext4_set_bit(ext4_block_bitmap(sb, gdp) - start, bh->b_data);
+		ext4_set_bit(ext4_inode_bitmap(sb, gdp) - 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++)
+			ext4_set_bit(bit, bh->b_data);
+	}
+
+	return free_blocks - sbi->s_itb_per_group - 2;
+}
+
 /*
  * The free blocks are managed by bitmaps.  A file system contains several
  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap

@@ -110,16 +179,29 @@
  *
  * Return buffer_head on success or NULL in case of failure.
  */
-static struct buffer_head *
+struct buffer_head *
 read_block_bitmap(struct super_block *sb, unsigned int block_group)
 {
 	struct ext4_group_desc * desc;
 	struct buffer_head * bh = NULL;
 
-	desc = ext4_get_group_desc (sb, block_group, NULL);
+	desc = ext4_get_group_desc(sb, block_group, NULL);
 	if (!desc)
 		goto error_out;
-	bh = sb_bread(sb, ext4_block_bitmap(sb, desc));
+	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+		bh = sb_getblk(sb, ext4_block_bitmap(sb, desc));
+		if (!buffer_uptodate(bh)) {
+			lock_buffer(bh);
+			if (!buffer_uptodate(bh)) {
+				ext4_init_block_bitmap(sb, bh, block_group,
+						       desc);
+				set_buffer_uptodate(bh);
+			}
+			unlock_buffer(bh);
+		}
+	} else {
+		bh = sb_bread(sb, ext4_block_bitmap(sb,desc));
+	}
 	if (!bh)
 		ext4_error (sb, "read_block_bitmap",
 			    "Cannot read block bitmap - "

@@ -586,6 +668,7 @@
 	desc->bg_free_blocks_count =
 		cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
 			group_freed);
+	desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
 	spin_unlock(sb_bgl_lock(sbi, block_group));
 	percpu_counter_mod(&sbi->s_freeblocks_counter, count);
 

@@ -1644,8 +1727,11 @@
 			ret_block, goal_hits, goal_attempts);
 
 	spin_lock(sb_bgl_lock(sbi, group_no));
+	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))
+		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 	gdp->bg_free_blocks_count =
 			cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
+	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
 	percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
 

Index: linux-2.6.23-rc4/fs/ext4/group.h
===================================================================
@@ -0,0 +1,29 @@
+/*
+ *  linux/fs/ext4/group.h
+ *
+ * Copyright (C) 2007 Cluster File Systems, Inc
+ *
+ * Author: Andreas Dilger <[email protected]>
+ */
+
+#ifndef _LINUX_EXT4_GROUP_H
+#define _LINUX_EXT4_GROUP_H
+#if defined(CONFIG_CRC16)
+#include <linux/crc16.h>
+#endif
+
+extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
+				   struct ext4_group_desc *gdp);
+extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
+				       struct ext4_group_desc *gdp);
+struct buffer_head *read_block_bitmap(struct super_block *sb,
+				      unsigned int block_group);
+extern unsigned ext4_init_block_bitmap(struct super_block *sb,
+				       struct buffer_head *bh, int group,
+				       struct ext4_group_desc *desc);
+#define ext4_free_blocks_after_init(sb, group, desc)			\
+		ext4_init_block_bitmap(sb, NULL, group, desc)
+extern unsigned ext4_init_inode_bitmap(struct super_block *sb,
+				       struct buffer_head *bh, int group,
+				       struct ext4_group_desc *desc);
+#endif /* _LINUX_EXT4_GROUP_H */

187 lines not on this page · raw message

Index: linux-2.6.23-rc4/fs/ext4/resize.c
===================================================================
@@ -16,6 +16,7 @@
 #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))

@@ -842,6 +843,7 @@
 	ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
 	gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
 	gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb));
+	gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
 
 	/*
 	 * Make the new blocks and inodes valid next.  We do this before

114 lines not on this page · raw message

Index: linux-2.6.23-rc4/include/linux/ext4_fs.h
===================================================================
@@ -123,19 +123,25 @@
  */
 struct ext4_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_flags;
-	__u32	bg_reserved[3];
+	__u16	bg_flags;		/* EXT4_BG_flags (INODE_UNINIT, etc) */
+	__u32	bg_reserved[2];		/* Likely block/inode bitmap checksum */
+	__le16  bg_itable_unused;	/* Unused inodes count */
+	__le16  bg_checksum;		/* crc16(sb_uuid+group+desc) */
 	__le32	bg_block_bitmap_hi;	/* Blocks bitmap block MSB */
 	__le32	bg_inode_bitmap_hi;	/* Inodes bitmap block MSB */
 	__le32	bg_inode_table_hi;	/* Inodes table block MSB */
 };
 
+#define EXT4_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not in use */
+#define EXT4_BG_BLOCK_UNINIT	0x0002 /* Block bitmap not in use */
+#define EXT4_BG_INODE_ZEROED	0x0004 /* On-disk itable initialized to zero */
+
 #ifdef __KERNEL__
 #include <linux/ext4_fs_i.h>
 #include <linux/ext4_fs_sb.h>

@@ -693,6 +699,7 @@
 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
 #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
 #define EXT4_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
 #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
 #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
 

@@ -712,6 +719,7 @@
 					 EXT4_FEATURE_INCOMPAT_64BIT)
 #define EXT4_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
 					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \
 					 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \
 					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR)

Index: linux-2.6.23-rc4/fs/ext4/mballoc.c
===================================================================
@@ -36,6 +36,8 @@
 #include <linux/seq_file.h>
 #include <linux/version.h>
 
+#include "group.h"
+
 /*
  * MUSTDO:
  *   - test ext4_ext_search_left() and ext4_ext_search_right()

@@ -321,6 +323,7 @@
 	unsigned long	bb_state;
 	unsigned long 	bb_tid;
 	struct ext4_free_metadata *bb_md_cur;
+	struct ext4_group_desc *bb_gdp;
 	unsigned short	bb_first_free;
 	unsigned short	bb_free;
 	unsigned short	bb_fragments;

@@ -921,10 +924,7 @@
 		if (first_group + i >= EXT4_SB(sb)->s_groups_count)
 			break;
 
-		err = -EIO;
-		desc = ext4_get_group_desc(sb, first_group + i, NULL);
-		if (desc == NULL)
-			goto out;
+		desc = EXT4_GROUP_INFO(sb, first_group + i)->bb_gdp;
 
 		err = -ENOMEM;
 		bh[i] = sb_getblk(sb, le32_to_cpu(desc->bg_block_bitmap));

@@ -939,7 +939,12 @@
 			unlock_buffer(bh[i]);
 			continue;
 		}
-
+		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+			ext4_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]);

@@ -1722,6 +1727,10 @@
 	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(EXT4_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 @@
 			}
 
 			ac->ac_groups_scanned++;
-			if (cr == 0)
+			if (cr == 0 || (e3b.bd_info->bb_gdp->bg_flags &
+					cpu_to_le16(EXT4_BG_BLOCK_UNINIT) &&
+					ac->ac_2order != 0))
 				ext4_mb_simple_scan_group(ac, &e3b);
 			else if (cr == 1 && ac->ac_g_ex.fe_len == sbi->s_stripe)
 				ext4_mb_scan_aligned(ac, &e3b);

@@ -2304,12 +2315,13 @@
 			i--;
 			goto err_freebuddy;
 		}
+		memset(meta_group_info[j], 0, len);
 		desc = ext4_get_group_desc(sb, i, NULL);
+		meta_group_info[j]->bb_gdp = desc;
 		if (desc == NULL) {
 			printk(KERN_ERR"EXT4-fs: can't read descriptor %u\n",i);
 			goto err_freebuddy;
 		}
-		memset(meta_group_info[j], 0, len);
 		set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
 			&meta_group_info[j]->bb_state);
 

@@ -2874,9 +2886,17 @@
 	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(EXT4_BG_BLOCK_UNINIT)) {
+		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+		gdp->bg_free_blocks_count =
+			cpu_to_le16(ext4_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 = ext4_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);
 

@@ -4256,6 +4276,7 @@
 	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 = ext4_group_desc_csum(sbi, block_group, gdp);
 	spin_unlock(sb_bgl_lock(sbi, block_group));
 	percpu_counter_mod(&sbi->s_freeblocks_counter, count);