[U-Boot] [PATCH 1/3] fat: write: fix broken write to fragmented files
Lukasz Majewski
lukma at denx.de
Mon Sep 16 21:38:01 UTC 2019
Hi Marek,
> The code for handing file overwrite incorrectly assumed that the file
> on disk is always contiguous. This resulted in corrupting disk
> structure every time when write to existing fragmented file happened.
> Fix this by adding proper check for cluster discontinuity and adjust
> chunk size on each partial write.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> ---
> fs/fat/fat_write.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
> index 729cf39630d..6cfa5b45652 100644
> --- a/fs/fat/fat_write.c
> +++ b/fs/fat/fat_write.c
> @@ -794,6 +794,8 @@ set_contents(fsdata *mydata, dir_entry *dentptr,
> loff_t pos, __u8 *buffer,
> newclust = get_fatent(mydata, endclust);
>
> + if ((newclust - 1) != endclust)
> + break;
> if (IS_LAST_CLUST(newclust, mydata->fatsize))
> break;
> if (CHECK_CLUST(newclust, mydata->fatsize)) {
> @@ -811,7 +813,7 @@ set_contents(fsdata *mydata, dir_entry *dentptr,
> loff_t pos, __u8 *buffer, offset = 0;
> else
> offset = pos - cur_pos;
> - wsize = min(cur_pos + actsize, filesize) - pos;
> + wsize = min_t(unsigned long long, actsize, filesize
> - cur_pos); if (get_set_cluster(mydata, curclust, offset,
> buffer, wsize, &actsize)) {
> printf("Error get-and-setting cluster\n");
> @@ -824,8 +826,6 @@ set_contents(fsdata *mydata, dir_entry *dentptr,
> loff_t pos, __u8 *buffer, if (filesize <= cur_pos)
> break;
>
> - /* CHECK: newclust = get_fatent(mydata, endclust); */
> -
> if (IS_LAST_CLUST(newclust, mydata->fatsize))
> /* no more clusters */
> break;
Reviewed-by: Lukasz Majewski <lukma at denx.de>
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/20190916/9542053b/attachment.sig>
More information about the U-Boot
mailing list