Re: O_DIRECT foolish question

[Bruno Diniz de Paula <diniz@cs.rutgers.edu>]

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Hi Andrew,

it worked perfectly on my box. Now I am going to try in my experiments
environment and I'll let you know if everything was ok.

Thanks a lot,

Bruno.

PS: BTW, is this patch going to be added to 2.4 kernel?

On Thu, 2003-02-13 at 12:31, Andrew Morton wrote:
> Bruno Diniz de Paula <diniz@cs.rutgers.edu> wrote:
> >
> > Thanks, Andrew. So, no chances of getting this working correctly on 2.4
> > kernel for now (I mean, reading files with size != n*block_size), and
> > I'd better give up on this... Is it the case, or you think there is
> > still something to do to get this working on ext2 and 2.4 kernel?
> > 
> 
> Oh I think we can probably fix this up.  Can you test this diff?
> 
> 
> diff -puN fs/buffer.c~o_direct-length-fix fs/buffer.c
> --- 24/fs/buffer.c~o_direct-length-fix	2003-02-13 09:23:34.000000000 -0800
> +++ 24-akpm/fs/buffer.c	2003-02-13 09:24:39.000000000 -0800
> @@ -2107,7 +2107,7 @@ int generic_direct_IO(int rw, struct ino
>  	int length;
>  
>  	length = iobuf->length;
> -	nr_blocks = length / blocksize;
> +	nr_blocks = (length + blocksize - 1) / blocksize;
>  	/* build the blocklist */
>  	for (i = 0; i < nr_blocks; i++, blocknr++) {
>  		struct buffer_head bh;
> @@ -2148,6 +2148,10 @@ int generic_direct_IO(int rw, struct ino
>  	retval = brw_kiovec(rw, 1, &iobuf, inode->i_dev, iobuf->blocks, blocksize);
>  	/* restore orig length */
>  	iobuf->length = length;
> +
> +	/* Return correct value for reads at eof */
> +	if (retval > 0 && retval > length)
> +		retval = length;
>   out:
>  
>  	return retval;
> 
> _
> 
> -
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-- 
Bruno Diniz de Paula <diniz@cs.rutgers.edu>
Rutgers University

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