Re: [patch]ext4: add block plug for .writepages

From: Kyungmin Park
Date: Tue Oct 11 2011 - 06:40:36 EST


On Tue, Oct 11, 2011 at 1:51 AM, Ted Ts'o <tytso@xxxxxxx> wrote:
> On Wed, Sep 28, 2011 at 11:09:40AM +0800, Shaohua Li wrote:
>> I searched a little bit, looks only ext4 need it. here is the patch.
>>
>>
>> Add block plug for ext4 .writepages. Though ext4 .writepages
>> already handles request merge very well, block plug is still
>> helpful to reduce block lock contention.
>>
>> Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>

Does it require to add blk_finish_plug(&plug) when error case?

+ blk_start_plug(&plug);
while (!ret && wbc->nr_to_write > 0) {

...
/* start a new transaction*/
handle = ext4_journal_start(inode, needed_blocks);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
"%ld pages, ino %lu; err %d", __func__,
wbc->nr_to_write, inode->i_ino, ret);
+ blk_finish_plug(&plug);
goto out_writepages;
}

Thank you,
Kyungmin Park-
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