linux-kernel - Re: [PATCH v2] exfat: check disk status during buffer write

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Message-ID: <CAPqOJe1Zb76YJA7mjY5i61pS7EHTRCHfWDciUr4-Q2RuExAsiA@mail.gmail.com>
Date: Wed, 24 Jul 2024 16:27:21 +0800
From: dongliang cui <cuidongliang390@...il.com>
To: Sungjong Seo <sj1557.seo@...sung.com>
Cc: Dongliang Cui <dongliang.cui@...soc.com>, linkinjeon@...nel.org, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	niuzhiguo84@...il.com, hao_hao.wang@...soc.com, ke.wang@...soc.com, 
	Zhiguo Niu <zhiguo.niu@...soc.com>
Subject: Re: [PATCH v2] exfat: check disk status during buffer write

On Wed, Jul 24, 2024 at 3:50 PM Sungjong Seo <sj1557.seo@...sung.com> wrote:
>
> > On Wed, Jul 24, 2024 at 3:03 PM Sungjong Seo <sj1557.seo@...sung.com>
> > wrote:
> > >
> [snip]
> > > >
> > > > +static int exfat_block_device_ejected(struct super_block *sb)
> > > > +{
> > > > +     struct backing_dev_info *bdi = sb->s_bdi;
> > > > +
> > > > +     return bdi->dev == NULL;
> > > > +}
> > > Have you tested with this again?
> > Yes, I tested it in this way. The user side can receive the -ENODEV error
> > after the device is ejected.
> > dongliang.cui@...vice:/data/tmp # dd if=/dev/zero of=test.img bs=1M
> > count=10240
> > dd: test.img: write error: No such device
> > 1274+0 records in
> > 1273+1 records out
> > 1335635968 bytes (1.2 G) copied, 8.060 s, 158 M/s
> Oops!, write() seems to return ENODEV that man page does not have.
> In exfat_map_cluster, it was necessary to distinguish and return error
> values, but now that explicitly differentiated error messages will be
> printed. So, why not return EIO again? It seem appropriate to return EIO
> instead of ENODEV from the read/write syscall.
Yes, indeed.
I will make the changes all together in the next version.
Thanks！
>
> >
> > >
> > > > +
> > > >  static int exfat_get_block(struct inode *inode, sector_t iblock,
> > > >               struct buffer_head *bh_result, int create)
> > > >  {
> > > > @@ -290,6 +298,9 @@ static int exfat_get_block(struct inode *inode,
> > > > sector_t iblock,
> > > >       sector_t valid_blks;
> > > >       loff_t pos;
> > > >
> > > > +     if (exfat_block_device_ejected(sb))
> > > This looks better than the modified location in the last patch.
> > > However, the caller of this function may not be interested in exfat
> > > error handling, so here we should call exfat_fs_error_ratelimit()
> > > with an appropriate error message.
> > Thank you for the reminder. I will make the changes in the next version.
> Sounds good!
>
> >
> > >
> > > > +             return -ENODEV;
> > > > +
> > > >       mutex_lock(&sbi->s_lock);
> > > >       last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
> > > >       if (iblock >= last_block && !create)
> > > > --
> > > > 2.25.1
> > >
> > >
>
>