Re: [patch 06/44] mm: trim more holes

[Neil Brown <neilb@suse.de>]

On Tuesday April 24, npiggin@suse.de wrote:
> 
> If prepare_write fails with AOP_TRUNCATED_PAGE, or if commit_write fails, then
> we may have failed the write operation despite prepare_write having
> instantiated blocks past i_size. Fix this, and consolidate the trimming into
> one place.
> 
..
> @@ -2025,40 +2012,53 @@ generic_file_buffered_write(struct kiocb
>  						cur_iov, iov_offset, bytes);
>  		flush_dcache_page(page);
>  		status = a_ops->commit_write(file, page, offset, offset+bytes);
> -		if (status == AOP_TRUNCATED_PAGE) {
> -			page_cache_release(page);
> -			continue;
> +		if (unlikely(status < 0))
> +			goto fs_write_aop_error;
> +		if (unlikely(copied != bytes)) {
> +			status = -EFAULT;
> +			goto fs_write_aop_error;
>  		}

It isn't clear to me that you are handling the case
       status == AOP_TRUNCATED_PAGE
here.  AOP_TRUNCATED_PAGE is > 0 (0x80001 to be precise)

Maybe ->commit_write cannot return AOP_TRUNCATED_PAGE.  If that is
true, then a comment to that effect (i.e. that the old code was wrong)
in the change log might easy review. 

Or did I miss something?

Thanks,
NeilBrown