Re: [PATCH V3] Allow SysRq emergency thaw to thaw frozen filesystems

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 16 Jan 2009 13:50:19 -0600
Eric Sandeen <sandeen@redhat.com> wrote:

> +void do_thaw_all(unsigned long unused)
> +{
> +	struct super_block *sb;
> +	char b[BDEVNAME_SIZE];
> +
> +	list_for_each_entry(sb, &super_blocks, s_list) {
> +		while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
> +			printk(KERN_WARNING "Emergency Thaw on %s\n",
> +			       bdevname(sb->s_bdev, b));
> +	}
> +	printk(KERN_WARNING "Emergency Thaw complete\n");
> +}

Is there any reason why we're not taking the appropriate locks here?

If so, please add a comment justifying the implementation.

> +/**
> + * emergency_thaw_all -- forcibly thaw every frozen filesystem
> + *
> + * Used for emergency unfreeze of all filesystems via SysRq
> + */
> +void emergency_thaw_all(void)
> +{
> +	pdflush_operation(do_thaw_all, 0);
> +}