Re: [PATCH] ext4: Optimize ext4 DIO overwrites

[Jan Kara <jack@suse.cz>]

On Thu 26-12-19 12:17:31, Theodore Y. Ts'o wrote:
> On Thu, Dec 19, 2019 at 08:28:23PM +0100, Jan Kara wrote:
> > > However depending on which patch lands first one may need a
> > > re-basing. Will conflict with this-
> > > https://marc.info/?l=linux-ext4&m=157613016931238&w=2
> > 
> > Yes, but the conflict is minor and trivial to resolve.
> > 
> 
> Is this the correct resolution?

Looks good to me as well.

								Honza

> 
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -447,6 +447,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
>  	struct inode *inode = file_inode(iocb->ki_filp);
>  	loff_t offset = iocb->ki_pos;
>  	size_t count = iov_iter_count(from);
> +	const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
>  	bool extend = false, unaligned_io = false;
>  	bool ilock_shared = true;
>  
> @@ -526,7 +527,9 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
>  		ext4_journal_stop(handle);
>  	}
>  
> -	ret = iomap_dio_rw(iocb, from, &ext4_iomap_ops, &ext4_dio_write_ops,
> +	if (ilock_shared)
> +		iomap_ops = &ext4_iomap_overwrite_ops;
> +	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
>  			   is_sync_kiocb(iocb) || unaligned_io || extend);
>  
>  	if (extend)
> 
>      	   	    	      	  - Ted
> 				  
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR