[U-Boot] [PATCH] fs: fat: fix bug when write size is less than a sector size

[Wolfgang Denk <wd@denx.de>]

Dear Josh Wu,

In message <1374134870-10154-1-git-send-email-josh.wu@atmel.com> you wrote:
> Tested in at91sam9x5ek and sama5d3x-ek in mmc fat.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> ---
> When I debugging this issue, I also find the thread talking about this:
>   http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/158698
> But finally no patch is send for this bug. So I send this and cc all the
> people in that thread. Hope it can be merged in 2013.07.

Definitely not.  This needs thurough testing before it can go
mainline.


> -	__u32 startsect;
> +	__u32 startsect, nr_sectors;
>  
>  	if (clustnum > 0)
>  		startsect = mydata->data_begin +
> @@ -571,7 +571,11 @@ set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
>  
>  	debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
>  
> -	if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
> +	nr_sectors = size / mydata->sect_size;
> +	if (nr_sectors == 0)
> +		nr_sectors = 1;

Why would this be needed?  The case of a partial write is covered
further down below in the code, in the "if (size % mydata->sect_size)"
part...



Best regards,

Wolfgang Denk

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