From: Andrew Morton <akpm@digeo.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC] how to fix is_local_disk()?
Date: Sun, 4 May 2003 14:05:37 -0700 [thread overview]
Message-ID: <20030504140537.50310417.akpm@digeo.com> (raw)
In-Reply-To: <20030504191013.A10659@lst.de>
Christoph Hellwig <hch@lst.de> wrote:
>
> ...
> +static void do_emergency_remount(unsigned long foo)
> +{
> + struct super_block *sb;
> +
> + spin_lock(&sb_lock);
> + list_for_each_entry(sb, &super_blocks, s_list) {
> + sb->s_count++;
> + spin_unlock(&sb_lock);
> + down_read(&sb->s_umount);
> + if (sb->s_bdev && !(sb->s_flags & MS_RDONLY))
> + do_remount_sb(sb, MS_RDONLY, NULL, 1);
> + drop_super(sb);
You might need to check sb->s_root in here after acquiring sb->s_umount.
Otherwise the fs may have been unmounted while the semaphore was being waited
upon.
About half of the s_umount grabbers perform that check. The others might be
buggy. I'm not sure - it's all rather gunky in there and hard to tell what
the rules are.
next prev parent reply other threads:[~2003-05-04 20:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-04 7:00 [RFC] how to fix is_local_disk()? Christoph Hellwig
2003-05-04 7:30 ` Andrew Morton
2003-05-04 7:53 ` Christoph Hellwig
2003-05-04 8:00 ` Andrew Morton
2003-05-04 17:10 ` Christoph Hellwig
2003-05-04 21:05 ` Andrew Morton [this message]
2003-05-05 7:41 ` viro
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