Re: [PATCH 3/6 ]Ext4: journal credits reservation fixes for DIO, fallocate

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On Wed, Aug 13, 2008 at 02:23:07PM +0530, Aneesh Kumar K.V wrote:
> > 
> >  	if (create && !handle) {
> >  		/* Direct IO write... */
> >  		if (max_blocks > DIO_MAX_BLOCKS)
> >  			max_blocks = DIO_MAX_BLOCKS;
> > -		handle = ext4_journal_start(inode, DIO_CREDITS +
> > -			      2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
> > +		dio_credits = ext4_data_trans_blocks(inode, max_blocks);
> > +		handle = ext4_journal_start(inode, dio_credits);
> 
> Even in data=journal mode directIO will put the buffer_heads to journal
> right ? . So should we use ext4_data_trans_blocks here ?
> 

That should be
Even in data=journal mode directIO will NOT put the buffer_heads to journal

> 
> 
> >  		if (IS_ERR(handle)) {
> >  			ret = PTR_ERR(handle);
> >  			goto out;
> > @@ -2222,7 +2214,7 @@ static int ext4_da_writepage(struct page
> >   * for DIO, writepages, and truncate
> >   */
> >  #define EXT4_MAX_WRITEBACK_PAGES      DIO_MAX_BLOCKS
> > -#define EXT4_MAX_WRITEBACK_CREDITS    DIO_CREDITS
> > +#define EXT4_MAX_WRITEBACK_CREDITS    25
> > 
> >  static int ext4_da_writepages(struct address_space *mapping,
> >  				struct writeback_control *wbc)
> > @@ -4429,7 +4421,8 @@ static int ext4_writeblocks_trans_credit


-aneesh