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Date: Thu, 21 Jul 2011 09:37:17 +0800
From: Yongqiang Yang <xiaoqiangnk@...il.com>
To: Andreas Dilger <aedilger@...il.com>
Cc: "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
"tytso@....edu" <tytso@....edu>
Subject: Re: [PATCH 2/2] ext4: remove ext4_free_blocks_after_init()
On Wed, Jul 20, 2011 at 11:41 PM, Andreas Dilger <aedilger@...il.com> wrote:
> On 2011-07-20, at 7:32 AM, Yongqiang Yang <xiaoqiangnk@...il.com> wrote:
>> This patch removes ext4_free_blocks_after_init() and simplifies
>> ext4_init_block_bitmap() a lot.
>
> Why not use the ext4_set_bits() function, exported in another patch, to set multiple bits?
That patch has not been merged. After it is merged, I will post
another patch doing this, this can easy Ted's work. That patch is a
part of resize, but this patch has nothing to do with it logically.
Thank you,
Yongqiang.
>
>> Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
>> ---
>> fs/ext4/balloc.c | 122 ++++++++++++++++++-----------------------------------
>> fs/ext4/ext4.h | 4 +-
>> 2 files changed, 43 insertions(+), 83 deletions(-)
>>
>> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
>> index f8224ad..2dd9820 100644
>> --- a/fs/ext4/balloc.c
>> +++ b/fs/ext4/balloc.c
>> @@ -55,60 +55,31 @@ static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
>> return 0;
>> }
>>
>> -static int ext4_group_used_meta_blocks(struct super_block *sb,
>> - ext4_group_t block_group,
>> - struct ext4_group_desc *gdp)
>> -{
>> - ext4_fsblk_t tmp;
>> - struct ext4_sb_info *sbi = EXT4_SB(sb);
>> - /* block bitmap, inode bitmap, and inode table blocks */
>> - int used_blocks = sbi->s_itb_per_group + 2;
>> -
>> - if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
>> - if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
>> - block_group))
>> - used_blocks--;
>> -
>> - if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),
>> - block_group))
>> - used_blocks--;
>> -
>> - tmp = ext4_inode_table(sb, gdp);
>> - for (; tmp < ext4_inode_table(sb, gdp) +
>> - sbi->s_itb_per_group; tmp++) {
>> - if (!ext4_block_in_group(sb, tmp, block_group))
>> - used_blocks -= 1;
>> - }
>> - }
>> - return used_blocks;
>> -}
>> -
>> -/* 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,
>> +/* Initializes an uninitialized block bitmap */
>> +void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
>> ext4_group_t block_group, struct ext4_group_desc *gdp)
>> {
>> + ext4_fsblk_t start, tmp;
>> int bit, bit_max;
>> ext4_group_t ngroups = ext4_get_groups_count(sb);
>> - unsigned free_blocks, group_blocks;
>> + unsigned group_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, "Checksum bad for group %u",
>> - block_group);
>> - ext4_free_blks_set(sb, gdp, 0);
>> - ext4_free_inodes_set(sb, gdp, 0);
>> - ext4_itable_unused_set(sb, gdp, 0);
>> - memset(bh->b_data, 0xff, sb->s_blocksize);
>> - return 0;
>> - }
>> - memset(bh->b_data, 0, sb->s_blocksize);
>> + int flex_bg = 0;
>> +
>> + J_ASSERT_BH(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, "Checksum bad for group %u",
>> + block_group);
>> + ext4_free_blks_set(sb, gdp, 0);
>> + ext4_free_inodes_set(sb, gdp, 0);
>> + ext4_itable_unused_set(sb, gdp, 0);
>> + memset(bh->b_data, 0xff, sb->s_blocksize);
>> + return;
>> }
>> + 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);
>> @@ -137,46 +108,37 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
>> group_blocks = EXT4_BLOCKS_PER_GROUP(sb);
>> }
>>
>> - free_blocks = group_blocks - bit_max;
>>
>> - if (bh) {
>> - ext4_fsblk_t start, tmp;
>> - int flex_bg = 0;
>> + for (bit = 0; bit < bit_max; bit++)
>> + ext4_set_bit(bit, bh->b_data);
>>
>> - for (bit = 0; bit < bit_max; bit++)
>> - ext4_set_bit(bit, bh->b_data);
>> + start = ext4_group_first_block_no(sb, block_group);
>>
>> - start = ext4_group_first_block_no(sb, block_group);
>> + flex_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG);
>>
>> - if (EXT4_HAS_INCOMPAT_FEATURE(sb,
>> - EXT4_FEATURE_INCOMPAT_FLEX_BG))
>> - flex_bg = 1;
>> + /* Set bits for block and inode bitmaps, and inode table */
>> + tmp = ext4_block_bitmap(sb, gdp);
>> + if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
>> + ext4_set_bit(tmp - start, bh->b_data);
>>
>> - /* Set bits for block and inode bitmaps, and inode table */
>> - tmp = ext4_block_bitmap(sb, gdp);
>> - if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
>> - ext4_set_bit(tmp - start, bh->b_data);
>> + tmp = ext4_inode_bitmap(sb, gdp);
>> + if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
>> + ext4_set_bit(tmp - start, bh->b_data);
>>
>> - tmp = ext4_inode_bitmap(sb, gdp);
>> - if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
>> + tmp = ext4_inode_table(sb, gdp);
>> + for (; tmp < ext4_inode_table(sb, gdp) +
>> + sbi->s_itb_per_group; tmp++) {
>> + if (!flex_bg ||
>> + ext4_block_in_group(sb, tmp, block_group))
>> ext4_set_bit(tmp - start, bh->b_data);
>> -
>> - tmp = ext4_inode_table(sb, gdp);
>> - for (; tmp < ext4_inode_table(sb, gdp) +
>> - sbi->s_itb_per_group; tmp++) {
>> - if (!flex_bg ||
>> - ext4_block_in_group(sb, tmp, block_group))
>> - ext4_set_bit(tmp - start, bh->b_data);
>> - }
>> - /*
>> - * Also if the number of blocks within the group is
>> - * less than the blocksize * 8 ( which is the size
>> - * of bitmap ), set rest of the block bitmap to 1
>> - */
>> - ext4_mark_bitmap_end(group_blocks, sb->s_blocksize * 8,
>> - bh->b_data);
>> }
>> - return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp);
>> + /*
>> + * Also if the number of blocks within the group is
>> + * less than the blocksize * 8 ( which is the size
>> + * of bitmap ), set rest of the block bitmap to 1
>> + */
>> + ext4_mark_bitmap_end(group_blocks, sb->s_blocksize * 8,
>> + bh->b_data);
>> }
>>
>>
>> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
>> index 62cee2b..eacaad2 100644
>> --- a/fs/ext4/ext4.h
>> +++ b/fs/ext4/ext4.h
>> @@ -1741,12 +1741,10 @@ extern struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
>> extern int ext4_should_retry_alloc(struct super_block *sb, int *retries);
>> struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
>> ext4_group_t block_group);
>> -extern unsigned ext4_init_block_bitmap(struct super_block *sb,
>> +extern void ext4_init_block_bitmap(struct super_block *sb,
>> struct buffer_head *bh,
>> ext4_group_t group,
>> struct ext4_group_desc *desc);
>> -#define ext4_free_blocks_after_init(sb, group, desc) \
>> - ext4_init_block_bitmap(sb, NULL, group, desc)
>> ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
>>
>> /* dir.c */
>> --
>> 1.7.5.1
>>
>> --
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>
--
Best Wishes
Yongqiang Yang
--
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