linux-ext4 - Re: BUG with delayed allocation

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Date:	Thu, 20 Mar 2008 09:51:58 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	ext4 <linux-ext4@...r.kernel.org>
Cc:	Mingming Cao <cmm@...ibm.com>, Eric Sandeen <sandeen@...hat.com>
Subject: Re: BUG with delayed allocation

This mail didn't seem to reach the list.

-aneesh

On Thu, Mar 20, 2008 at 12:02:55AM +0530, Aneesh Kumar K.V wrote:
> On Wed, Mar 19, 2008 at 09:42:13AM -0500, Eric Sandeen wrote:
> > Aneesh Kumar K.V wrote:
> > > Hi,
> > > 
> > > Eric actually observed it yesterday. I am able to reproduce it locally.
> > > With delayed allocation we are observing wrong value of i_size.
> > > 
> > > kenrel: 2.6.25-rc5 +
> > > With all the patches in the patch queue
> > 
> > ...
> > 
> > I also see this with only:
> > 
> > patches/delalloc-vfs.patch
> > patches/delalloc-ext4.patch
> > 
> > applied.
> 
> This one seems to work for me. Need to think a bit more about parallel
> truncate.
> 
> -aneesh
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 79930df..b74426d 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1488,6 +1488,43 @@ out:
>  
>  	return ret;
>  }
> +static int ext4_da_writepage(struct page *page,
> +				struct writeback_control *wbc)
> +{
> +	struct inode *inode = page->mapping->host;
> +	handle_t *handle = NULL;
> +	int ret = 0;
> +	int err;
> +
> +	if (ext4_journal_current_handle())
> +		goto out_fail;
> +
> +	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
> +	if (IS_ERR(handle)) {
> +		ret = PTR_ERR(handle);
> +		goto out_fail;
> +	}
> +
> +	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
> +		ret = nobh_writepage(page, ext4_get_block, wbc);
> +	else
> +		ret = block_write_full_page(page, ext4_get_block, wbc);
> +
> +	if (!ret && inode->i_size > EXT4_I(inode)->i_disksize) {
> +		EXT4_I(inode)->i_disksize = inode->i_size;
> +		ext4_mark_inode_dirty(handle, inode);
> +	}
> +
> +	err = ext4_journal_stop(handle);
> +	if (!ret)
> +		ret = err;
> +	return ret;
> +
> +out_fail:
> +	redirty_page_for_writepage(wbc, page);
> +	unlock_page(page);
> +	return ret;
> +}
>  
>  static int ext4_da_writepages(struct address_space *mapping,
>  				struct writeback_control *wbc)
> @@ -2015,7 +2052,7 @@ static const struct address_space_operations ext4_journalled_aops = {
>  static const struct address_space_operations ext4_da_aops = {
>  	.readpage	= ext4_readpage,
>  	.readpages	= ext4_readpages,
> -	.writepage	= ext4_writeback_writepage,
> +	.writepage	= ext4_da_writepage,
>  	.writepages	= ext4_da_writepages,
>  	.sync_page	= block_sync_page,
>  	.write_begin	= ext4_da_write_begin,
--
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