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ext4: add a function which sets up group blocks of a flex bg 

This patch adds a function named setup_new_flex_group_blocks() which
sets up group blocks of a flex bg.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Yongqiang Yang 2012-01-03 23:32:52 -05:00 committed by Theodore Ts'o
parent 28c7bac009
commit 33afdcc540
2 changed files with 258 additions and 0 deletions
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8
fs/ext4/ext4.h
View File

@ -511,6 +511,14 @@ struct ext4_new_group_data {
__u32 free_blocks_count;
};
/* Indexes used to index group tables in ext4_new_group_data */
enum {
BLOCK_BITMAP = 0, /* block bitmap */
INODE_BITMAP, /* inode bitmap */
INODE_TABLE, /* inode tables */
GROUP_TABLE_COUNT,
};
/*
* Flags used by ext4_map_blocks()
*/

250
fs/ext4/resize.c
View File

@ -233,6 +233,256 @@ static int extend_or_restart_transaction(handle_t *handle, int thresh)
return 0;
}
/*
* set_flexbg_block_bitmap() mark @count blocks starting from @block used.
*
* Helper function for ext4_setup_new_group_blocks() which set .
*
* @sb: super block
* @handle: journal handle
* @flex_gd: flex group data
*/
static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
struct ext4_new_flex_group_data *flex_gd,
ext4_fsblk_t block, ext4_group_t count)
{
ext4_group_t count2;
ext4_debug("mark blocks [%llu/%u] used\n", block, count);
for (count2 = count; count > 0; count -= count2, block += count2) {
ext4_fsblk_t start;
struct buffer_head *bh;
ext4_group_t group;
int err;
ext4_get_group_no_and_offset(sb, block, &group, NULL);
start = ext4_group_first_block_no(sb, group);
group -= flex_gd->groups[0].group;
count2 = sb->s_blocksize * 8 - (block - start);
if (count2 > count)
count2 = count;
if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
BUG_ON(flex_gd->count > 1);
continue;
}
err = extend_or_restart_transaction(handle, 1);
if (err)
return err;
bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
if (!bh)
return -EIO;
err = ext4_journal_get_write_access(handle, bh);
if (err)
return err;
ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
block - start, count2);
ext4_set_bits(bh->b_data, block - start, count2);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (unlikely(err))
return err;
brelse(bh);
}
return 0;
}
/*
* Set up the block and inode bitmaps, and the inode table for the new groups.
* This doesn't need to be part of the main transaction, since we are only
* changing blocks outside the actual filesystem. We still do journaling to
* ensure the recovery is correct in case of a failure just after resize.
* If any part of this fails, we simply abort the resize.
*
* setup_new_flex_group_blocks handles a flex group as follow:
* 1. copy super block and GDT, and initialize group tables if necessary.
* In this step, we only set bits in blocks bitmaps for blocks taken by
* super block and GDT.
* 2. allocate group tables in block bitmaps, that is, set bits in block
* bitmap for blocks taken by group tables.
*/
static int setup_new_flex_group_blocks(struct super_block *sb,
struct ext4_new_flex_group_data *flex_gd)
{
int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
ext4_fsblk_t start;
ext4_fsblk_t block;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
struct ext4_new_group_data *group_data = flex_gd->groups;
__u16 *bg_flags = flex_gd->bg_flags;
handle_t *handle;
ext4_group_t group, count;
struct buffer_head *bh = NULL;
int reserved_gdb, i, j, err = 0, err2;
BUG_ON(!flex_gd->count || !group_data ||
group_data[0].group != sbi->s_groups_count);
reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
/* This transaction may be extended/restarted along the way */
handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
if (IS_ERR(handle))
return PTR_ERR(handle);
group = group_data[0].group;
for (i = 0; i < flex_gd->count; i++, group++) {
unsigned long gdblocks;
gdblocks = ext4_bg_num_gdb(sb, group);
start = ext4_group_first_block_no(sb, group);
/* Copy all of the GDT blocks into the backup in this group */
for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
struct buffer_head *gdb;
ext4_debug("update backup group %#04llx\n", block);
err = extend_or_restart_transaction(handle, 1);
if (err)
goto out;
gdb = sb_getblk(sb, block);
if (!gdb) {
err = -EIO;
goto out;
}
err = ext4_journal_get_write_access(handle, gdb);
if (err) {
brelse(gdb);
goto out;
}
memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
gdb->b_size);
set_buffer_uptodate(gdb);
err = ext4_handle_dirty_metadata(handle, NULL, gdb);
if (unlikely(err)) {
brelse(gdb);
goto out;
}
brelse(gdb);
}
/* Zero out all of the reserved backup group descriptor
* table blocks
*/
if (ext4_bg_has_super(sb, group)) {
err = sb_issue_zeroout(sb, gdblocks + start + 1,
reserved_gdb, GFP_NOFS);
if (err)
goto out;
}
/* Initialize group tables of the grop @group */
if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
goto handle_bb;
/* Zero out all of the inode table blocks */
block = group_data[i].inode_table;
ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
block, sbi->s_itb_per_group);
err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
GFP_NOFS);
if (err)
goto out;
handle_bb:
if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
goto handle_ib;
/* Initialize block bitmap of the @group */
block = group_data[i].block_bitmap;
err = extend_or_restart_transaction(handle, 1);
if (err)
goto out;
bh = bclean(handle, sb, block);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
goto out;
}
if (ext4_bg_has_super(sb, group)) {
ext4_debug("mark backup superblock %#04llx (+0)\n",
start);
ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
1);
}
ext4_mark_bitmap_end(group_data[i].blocks_count,
sb->s_blocksize * 8, bh->b_data);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (err)
goto out;
brelse(bh);
handle_ib:
if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
continue;
/* Initialize inode bitmap of the @group */
block = group_data[i].inode_bitmap;
err = extend_or_restart_transaction(handle, 1);
if (err)
goto out;
/* Mark unused entries in inode bitmap used */
bh = bclean(handle, sb, block);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
goto out;
}
ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
sb->s_blocksize * 8, bh->b_data);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (err)
goto out;
brelse(bh);
}
bh = NULL;
/* Mark group tables in block bitmap */
for (j = 0; j < GROUP_TABLE_COUNT; j++) {
count = group_table_count[j];
start = (&group_data[0].block_bitmap)[j];
block = start;
for (i = 1; i < flex_gd->count; i++) {
block += group_table_count[j];
if (block == (&group_data[i].block_bitmap)[j]) {
count += group_table_count[j];
continue;
}
err = set_flexbg_block_bitmap(sb, handle,
flex_gd, start, count);
if (err)
goto out;
count = group_table_count[j];
start = group_data[i].block_bitmap;
block = start;
}
if (count) {
err = set_flexbg_block_bitmap(sb, handle,
flex_gd, start, count);
if (err)
goto out;
}
}
out:
brelse(bh);
err2 = ext4_journal_stop(handle);
if (err2 && !err)
err = err2;
return err;
}
/*
* Set up the block and inode bitmaps, and the inode table for the new group.
* This doesn't need to be part of the main transaction, since we are only