On Mon, Jul 18, 2011 at 11:09 AM, Tao Ma <tm@xxxxxx> wrote:
> On 07/18/2011 10:52 AM, Yongqiang Yang wrote:
>> This patch simplifies journal handling in ext4_setup_new_group_blocks().
>>
>>
>> Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
>> ---
>> fs/ext4/resize.c | 39 ++++++++++++++++++++-------------------
>> 1 files changed, 20 insertions(+), 19 deletions(-)
>>
>> diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
>> index c91653c..ac5b63d 100644
>> --- a/fs/ext4/resize.c
>> +++ b/fs/ext4/resize.c
>> @@ -171,8 +171,7 @@ static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
>> * If that fails, restart the transaction & regain write access for the
>> * buffer head which is used for block_bitmap modifications.
>> */
>> -static int extend_or_restart_transaction(handle_t *handle, int thresh,
>> - struct buffer_head *bh)
>> +static int extend_or_restart_transaction(handle_t *handle, int thresh)
>> {
>> int err;
>>
>> @@ -183,9 +182,8 @@ static int extend_or_restart_transaction(handle_t *handle, int thresh,
>> if (err < 0)
>> return err;
>> if (err) {
>> - if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
>> - return err;
>> - if ((err = ext4_journal_get_write_access(handle, bh)))
>> + err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
>> + if (err)
>> return err;
> you removed an ext4_journal_get_write_access here, and I didn't see you
> add it back anywhere.
This get_write_access() was used to guarantee modification on the
block bitmap is in the new handle in previous code. In previous code,
bitmap is modified everywhere in setup_group_blocks(), actually, this
makes things complicated, in this patch, the modifications on block
bitmap are batched and are done by ext4_set_bits() after
extend_or_restart_transaction(), so it is ok.
Thanks,
Yongqiang.
>
> Thanks
> Tao
>> }
>>
>> @@ -222,29 +220,24 @@ static int setup_new_group_blocks(struct super_block *sb,
>>
>> BUG_ON(input->group != sbi->s_groups_count);
>>
>> - if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
>> - err = PTR_ERR(bh);
>> - goto exit_journal;
>> - }
>> -
>> /* Copy all of the GDT blocks into the backup in this group */
>> for (i = 0, bit = 1, block = start + 1;
>> i < gdblocks; i++, block++, bit++) {
>> struct buffer_head *gdb;
>>
>> ext4_debug("update backup group %#04llx (+%d)\n", block, bit);
>> -
>> - if ((err = extend_or_restart_transaction(handle, 1, bh)))
>> - goto exit_bh;
>> + err = extend_or_restart_transaction(handle, 1);
>> + if (err)
>> + goto exit_journal;
>>
>> gdb = sb_getblk(sb, block);
>> if (!gdb) {
>> err = -EIO;
>> - goto exit_bh;
>> + goto exit_journal;
>> }
>> if ((err = ext4_journal_get_write_access(handle, gdb))) {
>> brelse(gdb);
>> - goto exit_bh;
>> + goto exit_journal;
>> }
>> lock_buffer(gdb);
>> memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
>> @@ -253,7 +246,7 @@ static int setup_new_group_blocks(struct super_block *sb,
>> err = ext4_handle_dirty_metadata(handle, NULL, gdb);
>> if (unlikely(err)) {
>> brelse(gdb);
>> - goto exit_bh;
>> + goto exit_journal;
>> }
>> brelse(gdb);
>> }
>> @@ -264,7 +257,17 @@ static int setup_new_group_blocks(struct super_block *sb,
>> err = sb_issue_zeroout(sb, gdblocks + start + 1, reserved_gdb,
>> GFP_NOFS);
>> if (err)
>> - goto exit_bh;
>> + goto exit_journal;
>> +
>> + err = extend_or_restart_transaction(handle, 2);
>> + if (err)
>> + goto exit_journal;
>> +
>> + bh = bclean(handle, sb, input->block_bitmap);
>> + if (IS_ERR(bh)) {
>> + err = PTR_ERR(bh);
>> + goto exit_journal;
>> + }
>>
>> if (ext4_bg_has_super(sb, input->group)) {
>> ext4_debug("mark backup group tables %#04llx (+0)\n", start);
>> @@ -288,8 +291,6 @@ static int setup_new_group_blocks(struct super_block *sb,
>> ext4_set_bits(bh->b_data, input->inode_table - start,
>> sbi->s_itb_per_group);
>>
>> - if ((err = extend_or_restart_transaction(handle, 2, bh)))
>> - goto exit_bh;
>>
>> ext4_mark_bitmap_end(input->blocks_count, sb->s_blocksize * 8,
>> bh->b_data);
>
>
--
Best Wishes
Yongqiang Yang
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