Hi Andreas,
I have ported your uninitialized block group kernel patch to mainline
2.6.22-rc3, included below.
I will also be posting the ported e2fsprogs patches. I had trouble
testing the patches because of inconsistency in the block_group
structure in e2fsprogs - which is only using ext2_block_group, and not
ext4_block_group.
Thanks
Avantika
---
diff -uprN linux-2.6.22-rc3/fs/ext4/balloc.c linux-2.6.22-rc3-uninit-patch/fs/ext4/balloc.c
--- linux-2.6.22-rc3/fs/ext4/balloc.c 2007-05-25 19:55:14.000000000 -0700
+++ linux-2.6.22-rc3-uninit-patch/fs/ext4/balloc.c 2007-06-04 16:37:12.000000000 -0700
@@ -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
@@ -110,16 +180,28 @@ struct ext4_group_desc * ext4_get_group_
*
* 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, 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 - "
@@ -586,6 +668,7 @@ 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);
@@ -1644,8 +1727,11 @@ 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);
diff -uprN linux-2.6.22-rc3/fs/ext4/group.h linux-2.6.22-rc3-uninit-patch/fs/ext4/group.h
--- linux-2.6.22-rc3/fs/ext4/group.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.22-rc3-uninit-patch/fs/ext4/group.h 2007-06-04 16:37:12.000000000 -0700
@@ -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) || defined(CONFIG_CRC16_MODULE)
+#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 */
diff -uprN linux-2.6.22-rc3/fs/ext4/ialloc.c linux-2.6.22-rc3-uninit-patch/fs/ext4/ialloc.c
--- linux-2.6.22-rc3/fs/ext4/ialloc.c 2007-05-25 19:55:14.000000000 -0700
+++ linux-2.6.22-rc3-uninit-patch/fs/ext4/ialloc.c 2007-06-04 16:37:12.000000000 -0700
@@ -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;
+
+ ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
+ for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
+ ext4_set_bit(i, bitmap);
+ if (i < end_bit)
+ memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
+}
+
+/* Initializes an uninitialized inode bitmap */
+unsigned ext4_init_inode_bitmap(struct super_block *sb,
+ struct buffer_head *bh, int block_group,
+ struct ext4_group_desc *gdp)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ J_ASSERT_BH(bh, buffer_locked(bh));
+
+ /* If checksum is bad mark all blocks and inodes 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, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
+ mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb),
+ bh->b_data);
+
+ return EXT4_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 = ext4_get_group_desc(sb, block_group, NULL);
if (!desc)
goto error_out;
-
- bh = sb_bread(sb, ext4_inode_bitmap(sb, desc));
+ if (desc->bg_flags & cpu_to_le16(EXT4_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)) {
+ ext4_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)
ext4_error(sb, "read_inode_bitmap",
"Cannot read inode bitmap - "
@@ -169,6 +227,8 @@ void ext4_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 = ext4_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)
@@ -438,7 +498,7 @@ struct inode *ext4_new_inode(handle_t *h
struct ext4_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)
@@ -520,11 +580,13 @@ repeat_in_this_group:
goto out;
got:
- ino += group * EXT4_INODES_PER_GROUP(sb) + 1;
- if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
- ext4_error (sb, "ext4_new_inode",
- "reserved inode or inode > inodes count - "
- "block_group = %d, inode=%lu", group, ino);
+ ino++;
+ if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
+ ino > EXT4_INODES_PER_GROUP(sb)) {
+ ext4_error(sb, __FUNCTION__,
+ "reserved inode or inode > inodes count - "
+ "block_group = %d, inode=%lu", group,
+ ino + group * EXT4_INODES_PER_GROUP(sb));
err = -EIO;
goto fail;
}
@@ -532,13 +594,65 @@ got:
BUFFER_TRACE(bh2, "get_write_access");
err = ext4_journal_get_write_access(handle, bh2);
if (err) goto fail;
+
+ /* We may have to initialize the block bitmap if it isn't already */
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
+ gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+ struct buffer_head *block_bh = read_block_bitmap(sb, group);
+
+ BUFFER_TRACE(block_bh, "get block bitmap access");
+ err = ext4_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(EXT4_BG_BLOCK_UNINIT)) {
+ gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+ free = ext4_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 = ext4_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 (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+ if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+ gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
+ free = EXT4_INODES_PER_GROUP(sb);
+ } else {
+ free = EXT4_INODES_PER_GROUP(sb) -
+ le16_to_cpu(gdp->bg_itable_unused);
+ }
+
+ if (ino > free) {
+ gdp->bg_itable_unused =
+ cpu_to_le16(EXT4_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 = ext4_group_desc_csum(sbi, group, gdp);
spin_unlock(sb_bgl_lock(sbi, group));
BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
err = ext4_journal_dirty_metadata(handle, bh2);
@@ -560,7 +674,7 @@ got:
inode->i_gid = current->fsgid;
inode->i_mode = mode;
- inode->i_ino = ino;
+ inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
/* This is the optimal IO size (for stat), not the fs block size */
inode->i_blocks = 0;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
diff -uprN linux-2.6.22-rc3/fs/ext4/resize.c linux-2.6.22-rc3-uninit-patch/fs/ext4/resize.c
--- linux-2.6.22-rc3/fs/ext4/resize.c 2007-05-25 19:55:14.000000000 -0700
+++ linux-2.6.22-rc3-uninit-patch/fs/ext4/resize.c 2007-06-04 16:37:12.000000000 -0700
@@ -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
diff -uprN linux-2.6.22-rc3/fs/ext4/super.c linux-2.6.22-rc3-uninit-patch/fs/ext4/super.c
--- linux-2.6.22-rc3/fs/ext4/super.c 2007-05-25 19:55:14.000000000 -0700
+++ linux-2.6.22-rc3-uninit-patch/fs/ext4/super.c 2007-06-04 16:39:06.000000000 -0700
@@ -41,6 +41,7 @@
#include "xattr.h"
#include "acl.h"
#include "namei.h"
+#include "group.h"
static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
unsigned long journal_devnum);
@@ -1223,6 +1224,90 @@ static int ext4_setup_super(struct super
return res;
}
+#if !defined(CONFIG_CRC16) && !defined(CONFIG_CRC16_MODULE)
+/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 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 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
+ struct ext4_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 ext4_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 (offset < sbi->s_es->s_desc_size) {
+ crc = crc16(crc, (__u8 *)gdp + offset,
+ sbi->s_es->s_desc_size - offset);
+ }
+ }
+
+ return cpu_to_le16(crc);
+}
+
+int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
+ struct ext4_group_desc *gdp)
+{
+ if (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp))
+ return 0;
+
+ return 1;
+}
+
/* Called at mount-time, super-block is locked */
static int ext4_check_descriptors (struct super_block * sb)
{
@@ -1277,6 +1362,13 @@ static int ext4_check_descriptors (struc
i, inode_table);
return 0;
}
+ if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
+ ext4_error(sb, __FUNCTION__,
+ "Checksum for group %d failed (%u!=%u)\n", i,
+ le16_to_cpu(ext4_group_desc_csum(sbi,i,gdp)),
+ le16_to_cpu(gdp->bg_checksum));
+ return 0;
+ }
first_block += EXT4_BLOCKS_PER_GROUP(sb);
gdp = (struct ext4_group_desc *)
((__u8 *)gdp + EXT4_DESC_SIZE(sb));
diff -uprN linux-2.6.22-rc3/include/linux/ext4_fs.h linux-2.6.22-rc3-uninit-patch/include/linux/ext4_fs.h
--- linux-2.6.22-rc3/include/linux/ext4_fs.h 2007-05-25 19:55:14.000000000 -0700
+++ linux-2.6.22-rc3-uninit-patch/include/linux/ext4_fs.h 2007-06-04 16:37:12.000000000 -0700
@@ -122,19 +122,25 @@
*/
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];
+ __u32 bg_reserved[2];
__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 */
+ __le16 bg_itable_unused; /* Unused inodes count */
+ __le16 bg_checksum; /* crc16(sb_uuid+group+desc) */
};
+#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>
@@ -596,6 +602,7 @@ 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_INCOMPAT_COMPRESSION 0x0001
#define EXT4_FEATURE_INCOMPAT_FILETYPE 0x0002
@@ -613,6 +620,7 @@ static inline int ext4_valid_inum(struct
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_BTREE_DIR)
/*
Avantika Mathur wrote:
> Hi Andreas,
>
> I have ported your uninitialized block group kernel patch to mainline
> 2.6.22-rc3, included below.
> I will also be posting the ported e2fsprogs patches. I had trouble
> testing the patches because of inconsistency in the block_group
> structure in e2fsprogs - which is only using ext2_block_group, and not
> ext4_block_group.
>
> Thanks
> Avantika
>
> ---
...
> +#if !defined(CONFIG_CRC16) && !defined(CONFIG_CRC16_MODULE)
> +/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 1) */
> +__u16 const crc16_table[256] = {
> + 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
> + 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
Apologies if this has already been discussed & I missed it, but why
replicate all this? why not just require CONFIG_CRC16?
-Eric
On Jun 05, 2007 13:48 -0500, Eric Sandeen wrote:
> Avantika Mathur wrote:
> >I have ported your uninitialized block group kernel patch to mainline
> >2.6.22-rc3, included below.
> >I will also be posting the ported e2fsprogs patches. I had trouble
> >testing the patches because of inconsistency in the block_group
> >structure in e2fsprogs - which is only using ext2_block_group, and not
> >ext4_block_group.
>
> >+#if !defined(CONFIG_CRC16) && !defined(CONFIG_CRC16_MODULE)
> >+/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 1) */
> >+__u16 const crc16_table[256] = {
> >+ 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
> >+ 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
>
>
> Apologies if this has already been discussed & I missed it, but why
> replicate all this? why not just require CONFIG_CRC16?
For CFS we need this in our patches because crc16() is not available in
older kernels. For 2.6.2x it is available, so there is not really any
need to included it unless you are building ext4 against an existing
kernel which does not have crc16() configured (it is not on by default).
I don't think it is harmful, but I don't care whether it is kept or not.
FYI, the other thing I noticed about the e2fsprogs part of this feature is
that PPC seems to break crc16(__u16 crc) and treat crc as a signed int.
This causes e.g. crc16(~0, buf, len) to calculate "crc >> 8" to be 0xffffff
and the resulting checksum is wrong.
I ended up working around the problem by passing unsigned int instead
of __u16 as a parameter, and masking the intermediate results in a
WORDS_BIGENDIAN environment, though I'm not sure if it is big-endian
that is at fault or only the PPC code. Attached is an updated e2fsprogs
patch for this, which includes crc16() regression tests that pass on PPC,
in addition to the ext2fs_group_desc_csum() tests which previously failed.
Thanks to Oregon State University (and IBM) for having public-access PPC
machines to test this on (http://powerdev.osuosl.org/).
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
Signed-off-by: Avantika Mathur <[email protected]>
---
diff -uprN linux-2.6.22-rc4/fs/ext4/balloc.c linux-2.6.22-rc4-patch/fs/ext4/balloc.c
--- linux-2.6.22-rc4/fs/ext4/balloc.c 2007-06-15 17:05:06.000000000 -0700
+++ linux-2.6.22-rc4-patch/fs/ext4/balloc.c 2007-06-15 16:53:58.000000000 -0700
@@ -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
@@ -110,16 +180,28 @@ struct ext4_group_desc * ext4_get_group_
*
* 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, 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 - "
@@ -586,6 +668,7 @@ 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);
@@ -1644,8 +1727,11 @@ 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);
diff -uprN linux-2.6.22-rc4/fs/ext4/group.h linux-2.6.22-rc4-patch/fs/ext4/group.h
--- linux-2.6.22-rc4/fs/ext4/group.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.22-rc4-patch/fs/ext4/group.h 2007-06-15 16:53:58.000000000 -0700
@@ -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) || defined(CONFIG_CRC16_MODULE)
+#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 */
diff -uprN linux-2.6.22-rc4/fs/ext4/ialloc.c linux-2.6.22-rc4-patch/fs/ext4/ialloc.c
--- linux-2.6.22-rc4/fs/ext4/ialloc.c 2007-06-15 17:05:17.000000000 -0700
+++ linux-2.6.22-rc4-patch/fs/ext4/ialloc.c 2007-06-15 16:53:58.000000000 -0700
@@ -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;
+
+ ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
+ for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
+ ext4_set_bit(i, bitmap);
+ if (i < end_bit)
+ memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
+}
+
+/* Initializes an uninitialized inode bitmap */
+unsigned ext4_init_inode_bitmap(struct super_block *sb,
+ struct buffer_head *bh, int block_group,
+ struct ext4_group_desc *gdp)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ J_ASSERT_BH(bh, buffer_locked(bh));
+
+ /* If checksum is bad mark all blocks and inodes 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, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
+ mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb),
+ bh->b_data);
+
+ return EXT4_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 = ext4_get_group_desc(sb, block_group, NULL);
if (!desc)
goto error_out;
-
- bh = sb_bread(sb, ext4_inode_bitmap(sb, desc));
+ if (desc->bg_flags & cpu_to_le16(EXT4_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)) {
+ ext4_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)
ext4_error(sb, "read_inode_bitmap",
"Cannot read inode bitmap - "
@@ -169,6 +227,8 @@ void ext4_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 = ext4_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)
@@ -438,7 +498,7 @@ struct inode *ext4_new_inode(handle_t *h
struct ext4_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)
@@ -520,11 +580,13 @@ repeat_in_this_group:
goto out;
got:
- ino += group * EXT4_INODES_PER_GROUP(sb) + 1;
- if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
- ext4_error (sb, "ext4_new_inode",
- "reserved inode or inode > inodes count - "
- "block_group = %d, inode=%lu", group, ino);
+ ino++;
+ if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
+ ino > EXT4_INODES_PER_GROUP(sb)) {
+ ext4_error(sb, __FUNCTION__,
+ "reserved inode or inode > inodes count - "
+ "block_group = %d, inode=%lu", group,
+ ino + group * EXT4_INODES_PER_GROUP(sb));
err = -EIO;
goto fail;
}
@@ -532,13 +594,65 @@ got:
BUFFER_TRACE(bh2, "get_write_access");
err = ext4_journal_get_write_access(handle, bh2);
if (err) goto fail;
+
+ /* We may have to initialize the block bitmap if it isn't already */
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
+ gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+ struct buffer_head *block_bh = read_block_bitmap(sb, group);
+
+ BUFFER_TRACE(block_bh, "get block bitmap access");
+ err = ext4_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(EXT4_BG_BLOCK_UNINIT)) {
+ gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+ free = ext4_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 = ext4_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 (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+ if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+ gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
+ free = EXT4_INODES_PER_GROUP(sb);
+ } else {
+ free = EXT4_INODES_PER_GROUP(sb) -
+ le16_to_cpu(gdp->bg_itable_unused);
+ }
+
+ if (ino > free) {
+ gdp->bg_itable_unused =
+ cpu_to_le16(EXT4_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 = ext4_group_desc_csum(sbi, group, gdp);
spin_unlock(sb_bgl_lock(sbi, group));
BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
err = ext4_journal_dirty_metadata(handle, bh2);
@@ -560,7 +674,7 @@ got:
inode->i_gid = current->fsgid;
inode->i_mode = mode;
- inode->i_ino = ino;
+ inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
/* This is the optimal IO size (for stat), not the fs block size */
inode->i_blocks = 0;
inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
diff -uprN linux-2.6.22-rc4/fs/ext4/resize.c linux-2.6.22-rc4-patch/fs/ext4/resize.c
--- linux-2.6.22-rc4/fs/ext4/resize.c 2007-06-04 17:57:25.000000000 -0700
+++ linux-2.6.22-rc4-patch/fs/ext4/resize.c 2007-06-15 16:53:58.000000000 -0700
@@ -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
diff -uprN linux-2.6.22-rc4/fs/ext4/super.c linux-2.6.22-rc4-patch/fs/ext4/super.c
--- linux-2.6.22-rc4/fs/ext4/super.c 2007-06-15 17:05:18.000000000 -0700
+++ linux-2.6.22-rc4-patch/fs/ext4/super.c 2007-06-15 16:53:58.000000000 -0700
@@ -41,6 +41,7 @@
#include "xattr.h"
#include "acl.h"
#include "namei.h"
+#include "group.h"
static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
unsigned long journal_devnum);
@@ -1231,6 +1232,90 @@ static int ext4_setup_super(struct super
return res;
}
+#if !defined(CONFIG_CRC16) && !defined(CONFIG_CRC16_MODULE)
+/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 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 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
+ struct ext4_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 ext4_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 (offset < sbi->s_es->s_desc_size) {
+ crc = crc16(crc, (__u8 *)gdp + offset,
+ sbi->s_es->s_desc_size - offset);
+ }
+ }
+
+ return cpu_to_le16(crc);
+}
+
+int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
+ struct ext4_group_desc *gdp)
+{
+ if (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp))
+ return 0;
+
+ return 1;
+}
+
/* Called at mount-time, super-block is locked */
static int ext4_check_descriptors (struct super_block * sb)
{
@@ -1285,6 +1370,13 @@ static int ext4_check_descriptors (struc
i, inode_table);
return 0;
}
+ if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
+ ext4_error(sb, __FUNCTION__,
+ "Checksum for group %d failed (%u!=%u)\n", i,
+ le16_to_cpu(ext4_group_desc_csum(sbi,i,gdp)),
+ le16_to_cpu(gdp->bg_checksum));
+ return 0;
+ }
first_block += EXT4_BLOCKS_PER_GROUP(sb);
gdp = (struct ext4_group_desc *)
((__u8 *)gdp + EXT4_DESC_SIZE(sb));
diff -uprN linux-2.6.22-rc4/include/linux/ext4_fs.h linux-2.6.22-rc4-patch/include/linux/ext4_fs.h
--- linux-2.6.22-rc4/include/linux/ext4_fs.h 2007-06-15 17:05:24.000000000 -0700
+++ linux-2.6.22-rc4-patch/include/linux/ext4_fs.h 2007-06-15 16:57:27.000000000 -0700
@@ -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];
+ __u32 bg_reserved[2];
__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 */
+ __le16 bg_itable_unused; /* Unused inodes count */
+ __le16 bg_checksum; /* crc16(sb_uuid+group+desc) */
};
+#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>
@@ -681,6 +687,7 @@ static inline int ext4_valid_inum(struct
#define EXT4_FEATURE_COMPAT_EXT_ATTR 0x0008
#define EXT4_FEATURE_COMPAT_RESIZE_INODE 0x0010
#define EXT4_FEATURE_COMPAT_DIR_INDEX 0x0020
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0040
#define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT4_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
@@ -706,6 +713,7 @@ 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)
/*
Binary files linux-2.6.22-rc4/include/linux/.ext4_fs.h.rej.swp and linux-2.6.22-rc4-patch/include/linux/.ext4_fs.h.rej.swp differ
On Jun 18, 2007 21:04 -0700, Avantika Mathur wrote:
> Here is the uninitialized block group patch, rebased to the ext4 git
> tree, after ext4_remove_subdirs_limit.patch.
> Andreas, please let me know if there are any issues with the patch
> +__le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
> + struct ext4_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 ext4_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 (offset < sbi->s_es->s_desc_size) {
This is missing an le16_to_cpu(sbi->s_es->s_desc_size) conversion. I missed
it in my sparse checking because it was commented out. Also, s_desc_size is
only valid in conjunction with INCOMPAT_64BIT I think, so that should be
checked also.
> @@ -681,6 +687,7 @@ static inline int ext4_valid_inum(struct
> #define EXT4_FEATURE_COMPAT_EXT_ATTR 0x0008
> #define EXT4_FEATURE_COMPAT_RESIZE_INODE 0x0010
> #define EXT4_FEATURE_COMPAT_DIR_INDEX 0x0020
> +#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0040
This is the wrong feature number. It should be 0x0010 as in the original
patch, and as reserved in the upstream e2fsprogs. The confusion is because
you added this to the "FEATURE_COMPAT" section instead of the
FEATURE_RO_COMPAT section of the headers.
I've asked Girish to send an incremental patch.
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
>
> I've asked Girish to send an incremental patch.
>
Here is the incremental patch, to be applied after the patch sent by
Avantika for 2.6.22-rc4 kernel.
Regards,
Girish.
On Jun 20, 2007 17:26 +0530, Girish Shilamkar wrote:
> crc = crc16(crc, (__u8 *)gdp + offset,
> - sbi->s_es->s_desc_size - offset);
> + le16_to_cpu(sbi->s_es->s_desc_size)
> + - offset);
Minor nit - please put '-' at the end of the previous line, and align
"offset" with '(sbi-> ...'.
Also, we're missing the signoff:
Signed-off-by: Andreas Dilger <[email protected]>
Signed-off-by: Girish Shilamkar <[email protected]>
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
Kernel build was failing with the uninitialized patches when
CONFIG_CRC16=m. The patch below resolves this issue.
Also, when testing the patches, filesystem mount fails:
EXT4-fs error (device sdc1): ext4_check_descriptors: Checksum for group 1 failed (0!=1)
EXT4-fs: group descriptors corrupted!
EXT4-fs error (device sdc1): ext4_check_descriptors: Checksum for group 7 failed (0!=1)
Even though the uninitgrps feature is not enabled, the gdp->bg_checksum
on disk is nonzero.
Mingming will pull the patches out of the patch queue until this is fixed.
Thanks
Avantika
---
On Jun 21, 2007 16:54 -0700, Avantika Mathur wrote:
> Kernel build was failing with the uninitialized patches when
> CONFIG_CRC16=m. The patch below resolves this issue.
No patch?
> Also, when testing the patches, filesystem mount fails:
>
> EXT4-fs error (device sdc1): ext4_check_descriptors: Checksum for group 1
> failed (0!=1)
>
> EXT4-fs: group descriptors corrupted!
>
> EXT4-fs error (device sdc1): ext4_check_descriptors: Checksum for group 7
> failed (0!=1)
>
> Even though the uninitgrps feature is not enabled, the gdp->bg_checksum
> on disk is nonzero.
Can you figure out why the on-disk checksum is non-zero? That should not
happen. Is it possible that the kernel patch and e2fsprogs somehow have
the wrong struct alignment? Is mke2fs not zeroing out the on-disk data -
the error is reporting that bg_checksum on disk is 1 when it should be 0?
I suppose it is possible for the patch to just ignore the on-disk data if
checksums are not enabled, but we didn't have any such problems in the past...
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
On Thu, 2007-06-21 at 16:54 -0700, Avantika Mathur wrote:
> Kernel build was failing with the uninitialized patches when
> CONFIG_CRC16=m. The patch below resolves this issue.
Why does ext4 duplicate lib/crc16.c? What's wrong with putting "select
CRC16" in Kconfig?
How about this instead?
Signed-off-by: Dave Kleikamp <[email protected]>
diff -urp linux-2.6.22-rc5-ext4/fs/Kconfig linux/fs/Kconfig
--- linux-2.6.22-rc5-ext4/fs/Kconfig 2007-06-22 10:08:49.000000000 -0500
+++ linux/fs/Kconfig 2007-06-22 11:13:08.000000000 -0500
@@ -139,6 +139,7 @@ config EXT3_FS_SECURITY
config EXT4DEV_FS
tristate "Ext4dev/ext4 extended fs support development (EXPERIMENTAL)"
depends on EXPERIMENTAL
+ select CRC16
select JBD2
help
Ext4dev is a predecessor filesystem of the next generation
diff -urp linux-2.6.22-rc5-ext4/fs/ext4/group.h linux/fs/ext4/group.h
--- linux-2.6.22-rc5-ext4/fs/ext4/group.h 2007-06-22 10:10:52.000000000 -0500
+++ linux/fs/ext4/group.h 2007-06-22 11:09:32.000000000 -0500
@@ -8,9 +8,7 @@
#ifndef _LINUX_EXT4_GROUP_H
#define _LINUX_EXT4_GROUP_H
-#if defined(CONFIG_CRC16) || defined(CONFIG_CRC16_MODULE)
#include <linux/crc16.h>
-#endif
extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
struct ext4_group_desc *gdp);
diff -urp linux-2.6.22-rc5-ext4/fs/ext4/super.c linux/fs/ext4/super.c
--- linux-2.6.22-rc5-ext4/fs/ext4/super.c 2007-06-22 10:10:53.000000000 -0500
+++ linux/fs/ext4/super.c 2007-06-22 11:13:37.000000000 -0500
@@ -1260,56 +1260,6 @@ static int ext4_setup_super(struct super
return res;
}
-#if !defined(CONFIG_CRC16) && !defined(CONFIG_CRC16_MODULE)
-/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 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 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
struct ext4_group_desc *gdp)
{
--
David Kleikamp
IBM Linux Technology Center