Re: UBIFS partition on NOR flash not mountable after power cut test

[Artem Bityutskiy <dedekind1@gmail.com>]

On Thu, 2010-12-02 at 14:23 +0100, Anatolij Gustschin wrote:
> On Thu, 02 Dec 2010 14:18:45 +0200
> Artem Bityutskiy <dedekind1@gmail.com> wrote:
> 
> > On Thu, 2010-12-02 at 10:57 +0100, Anatolij Gustschin wrote:
> > > UBIFS DBG (pid 1290): no_more_nodes: unexpected bad common header at 37:157472
> > > UBIFS error (pid 1290): ubifs_recover_leb: bad node
> > > UBIFS error (pid 1290): ubifs_scanned_corruption: corruption at LEB 37:157472
> > > UBIFS error (pid 1290): ubifs_scanned_corruption: first 8192 bytes from LEB 37:157472
> > > 00000000: 31181006 270758c8 0c331500 00000000 ffffffff ffffffff ff4fffff f3428020  1...'.X..3...............O...B. 
> > 
> > But this looks exactly like you have 64-bit write-buffer, but UBIFS
> > c->min_io_unit is not 64, but it should be 64. Or you need a NOR hack to
> > force 8-bytes write-buffer.
> 
> This looks exactly like I have a 16 byte write buffer. The first
> 16 bytes of the common header node have been written correctly but
> the remaining 8 bytes of the common header and then the 8 bytes of
> the data are corrupt.
> > 
> > Are you sure you did not miss your NOR write-buffer hacks?
> 
> I'm sure that the kernel running this test uses the modification in
> the CFI code as follows:
> diff --git a/drivers/mtd/chips/cfi_probe.c b/drivers/mtd/chips/cfi_probe.c
> index e63e674..9eb47b8 100644
> --- a/drivers/mtd/chips/cfi_probe.c
> +++ b/drivers/mtd/chips/cfi_probe.c
> @@ -213,6 +213,12 @@ static int __xipram cfi_chip_setup(struct map_info *map,
>         cfi->cfiq->InterfaceDesc = le16_to_cpu(cfi->cfiq->InterfaceDesc);
>         cfi->cfiq->MaxBufWriteSize = le16_to_cpu(cfi->cfiq->MaxBufWriteSize);
>  
> +       /*printk("NOTE: change CFI MaxBufWriteSize from 2^%d to 2^%d\n",*/
> +       /*cfi->cfiq->MaxBufWriteSize, 3);*/
> +       if (cfi->cfiq->MaxBufWriteSize) {
> +               cfi->cfiq->MaxBufWriteSize = 3;
> +       }
> +
> 
> But I'm not sure whether the CFI driver is really using 8 byte
> write buffer since the error pattern indicates the usage of a
> bigger buffer. I'll check the actual size used in the CFI driver
> at runtime.

Can you instead make mtd->writesize to be 64? This is much closer to the
"right thing to do" :-)

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)