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Subject: Re: [PATCH 3/5] UBI: switch the UBI device in read-only mode when mtd
 returns -EROFS
To: Boris Brezillon <boris.brezillon@free-electrons.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        linux-mtd@lists.infradead.org, Artem Bityutskiy <dedekind1@gmail.com>
References: <1443193758-22071-1-git-send-email-boris.brezillon@free-electrons.com>
 <1443193758-22071-4-git-send-email-boris.brezillon@free-electrons.com>
Cc: Andrea Scian <rnd4@dave-tech.it>,
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	<beanhuo@micron.com>,
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	<karlzhang@micron.com>,
        Iwo Mergler <Iwo.Mergler@netcommwireless.com>,
        "Jeff Lauruhn (jlauruhn)" <jlauruhn@micron.com>,
        Stefan Roese <sr@denx.de>, linux-kernel@vger.kernel.org
From: Richard Weinberger <richard@nod.at>
Message-ID: <560585B2.3020904@nod.at>
Date: Fri, 25 Sep 2015 19:34:42 +0200
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Am 25.09.2015 um 17:09 schrieb Boris Brezillon:
> The NAND layer is now able to forward power-cut emulation errors from
> a NAND driver to the MTD user.
> Check for this kind of errors in UBI and switch the UBI device in read-only
> mode if such an error occurs.
> The error will also be forwarded to the UBI user requesting the operation
> if any, thus allowing UBIFS to act accordingly.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
>  drivers/mtd/ubi/io.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
> index 5bbd1f0..c5ebef7 100644
> --- a/drivers/mtd/ubi/io.c
> +++ b/drivers/mtd/ubi/io.c
> @@ -303,6 +303,8 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
>  		len = ubi->peb_size - offset;
>  		if (len)
>  			err = ubi_self_check_all_ff(ubi, pnum, offset, len);
> +	} else if (err == -EROFS) {
> +		ubi_ro_mode(ubi);
>  	}
>  
>  	return err;
> @@ -355,7 +357,7 @@ retry:
>  
>  	err = mtd_erase(ubi->mtd, &ei);
>  	if (err) {
> -		if (retries++ < UBI_IO_RETRIES) {
> +		if (err != -EROFS && retries++ < UBI_IO_RETRIES) {

Looks good! :)
One small nit, can you please add a comment above both lines that the EROFS checks are
here because of emulators.

Thanks,
//richard