[U-Boot] [PATCH v2 2/6] fat: write: fix broken write at non-zero file offset

[Lukasz Majewski]

Hi Marek,

> Handling of the start file offset was broken in the current code.
> Although the code skipped the needed clusters, it then tried to
> continue write with current cluster set to EOF, what caused
> assertion. It also lacked adjusting filesize in case of writing at
> the end of file and adjusting in-cluster offset for partial overwrite.
> 
> This patch fixes all those issues.

Reviewed-by: Lukasz Majewski <lukma at denx.de>

> 
> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> ---
>  fs/fat/fat_write.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
> index 6cfa5b4565..d7a814eb0c 100644
> --- a/fs/fat/fat_write.c
> +++ b/fs/fat/fat_write.c
> @@ -756,14 +756,12 @@ set_contents(fsdata *mydata, dir_entry
> *dentptr, loff_t pos, __u8 *buffer, /* go to cluster at pos */
>  	cur_pos = bytesperclust;
>  	while (1) {
> +		newclust = get_fatent(mydata, curclust);
>  		if (pos <= cur_pos)
>  			break;
> -		if (IS_LAST_CLUST(curclust, mydata->fatsize))
> +		if (IS_LAST_CLUST(newclust, mydata->fatsize))
>  			break;
> -
> -		newclust = get_fatent(mydata, curclust);
> -		if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
> -		    CHECK_CLUST(newclust, mydata->fatsize)) {
> +		if (CHECK_CLUST(newclust, mydata->fatsize)) {
>  			debug("curclust: 0x%x\n", curclust);
>  			debug("Invalid FAT entry\n");
>  			return -1;
> @@ -772,8 +770,9 @@ set_contents(fsdata *mydata, dir_entry *dentptr,
> loff_t pos, __u8 *buffer, cur_pos += bytesperclust;
>  		curclust = newclust;
>  	}
> -	if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
> +	if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
>  		assert(pos == cur_pos);
> +		filesize -= pos;
>  		goto set_clusters;
>  	}
>  
> @@ -814,6 +813,7 @@ set_contents(fsdata *mydata, dir_entry *dentptr,
> loff_t pos, __u8 *buffer, else
>  			offset = pos - cur_pos;
>  		wsize = min_t(unsigned long long, actsize, filesize
> - cur_pos);
> +		wsize -= offset;
>  		if (get_set_cluster(mydata, curclust, offset,
>  				    buffer, wsize, &actsize)) {
>  			printf("Error get-and-setting cluster\n");




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma at denx.de
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 488 bytes
Desc: OpenPGP digital signature
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20190924/29ae8096/attachment.sig>