[PATCH v3] fs: fat: Handle 'FAT sector size mismatch'

[Varadarajan Narayanan]

Balaji,

> On 1/29/2026 2:11 AM, Tom Rini wrote:
> > On Thu, Jan 22, 2026 at 12:04:42PM +0530, Balaji Selvanathan wrote:
> >
> > > From: Varadarajan Narayanan <varadarajan.narayanan at oss.qualcomm.com>
> > >
> > > Do FAT read and write based on the device sector size
> > > instead of the size recorded in the FAT meta data.
> > >
> > > FAT code issues i/o in terms of the sector size. Convert that to
> > > device sector size before doing the actual i/o. Additionally,
> > > handle leading/trailing blocks when the meta data based block
> > > no and i/o size is not an exact multiple of the device sector
> > > size or vice versa.
> > >
> > > Tested on UFS device with sector size 4096 and meta data recorded
> > > sector size 512.
> > >
> > > Signed-off-by: Varadarajan Narayanan <varadarajan.narayanan at oss.qualcomm.com>
> > First thing, clang shows a lot of warnings from this:
> > https://source.denx.de/u-boot/u-boot/-/jobs/1365316
> > Second thing, filesystem tests do pass:
> > https://source.denx.de/u-boot/u-boot/-/jobs/1365314
> > Please make sure v4 is put through CI:
> > https://docs.u-boot.org/en/latest/develop/ci_testing.html
>
> Sure, will address the warnings and will put v4 through CI.

Have posted v4. Please see [1].

Tom,

The CI failed while building am33xx kirkwood. When I locally reverted
the v4 change and tried to build amxx related platforms, I was getting
similar errors. It doesn't appear to be related to this change. I might
be wrong. Please let me know if that issue has to be resolved.

Thanks
Varada

1 - https://lore.kernel.org/u-boot/20260213053719.2590474-1-varadarajan.narayanan@oss.qualcomm.com/