Re: [RFC] ext3 freeze feature

Pekka Enberg
2008-01-25T11:17:46Z

Hi,

> diff -uprN -X linux-2.6.24-rc8/Documentation/dontdiff linux-2.6.24-rc8/include/linux/ext3_fs_sb.h linux-2.6.24-rc8-freeze/include/linux/ext3_fs_sb.h
> --- linux-2.6.24-rc8/include/linux/ext3_fs_sb.h 2008-01-16 13:22:48.000000000 +0900
> +++ linux-2.6.24-rc8-freeze/include/linux/ext3_fs_sb.h 2008-01-22 18:20:33.000000000 +0900
> @@ -81,6 +81,8 @@ struct ext3_sb_info {
> char *s_qf_names[MAXQUOTAS]; /* Names of quota files with journalled quota */
> int s_jquota_fmt; /* Format of quota to use */
> #endif
> + /* Delayed work for freeze */
> + struct delayed_work s_freeze_timeout;

Why not put this in struct super_block? Then you don't need this

> +/**
> + * get_super_block - get super_block
> + * @s_fs_info : filesystem dependent information
> + * (super_block.s_fs_info)
> + *
> + * Get super_block which holds s_fs_info from super_blocks.
> + * get_super_block() returns a pointer of super block or
> + * %NULL if it have failed.
> + */
> +struct super_block *get_super_block(void *s_fs_info)
> +{

And these can be put to generic code:

> /*
> + * ext3_add_freeze_timeout - Add timeout for ext3 freeze.
> + *
> + * @sbi : ext3 super block
> + * @timeout_msec : timeout period
> + *
> + * Add the delayed work for ext3 freeze timeout
> + * to the delayed work queue.
> + */
> +void ext3_add_freeze_timeout(struct ext3_sb_info *sbi,
> + long timeout_msec)
> +{
> + s64 timeout_jiffies = msecs_to_jiffies(timeout_msec);
> +
> + /*
> + * setup freeze timeout function
> + */
> + INIT_DELAYED_WORK(&sbi->s_freeze_timeout, ext3_freeze_timeout);
> +
> + /* set delayed work queue */
> + cancel_delayed_work(&sbi->s_freeze_timeout);
> + schedule_delayed_work(&sbi->s_freeze_timeout, timeout_jiffies);
> +}
> +
> +/*
> + * ext3_del_freeze_timeout - Delete timeout for ext3 freeze.
> + *
> + * @sbi : ext3 super block
> + *
> + * Delete the delayed work for ext3 freeze timeout
> + * from the delayed work queue.
> + */
> +void ext3_del_freeze_timeout(struct ext3_sb_info *sbi)
> +{
> + if (delayed_work_pending(&sbi->s_freeze_timeout))
> + cancel_delayed_work(&sbi->s_freeze_timeout);
> +}

> +/*
> + * ext3_freeze_timeout - Thaw the filesystem.
> + *
> + * @work : work queue (delayed_work.work)
> + *
> + * Called by the delayed work when elapsing the timeout period.
> + * Thaw the filesystem.
> + */
> +static void ext3_freeze_timeout(struct work_struct *work)
> +{
> + struct ext3_sb_info *sbi = container_of(work,
> + struct ext3_sb_info,
> + s_freeze_timeout.work);
> + struct super_block *sb = get_super_block(sbi);
> +
> + BUG_ON(sb == NULL);
> +
> + if (sb->s_frozen != SB_UNFROZEN)
> + thaw_bdev(sb->s_bdev, sb);
> +}
> +

I am also wondering whether we should have system call(s) for these:

On Jan 25, 2008 12:59 PM, Takashi Sato <t-sato@yk.jp.nec.com> wrote:
> + case EXT3_IOC_FREEZE: {

> + case EXT3_IOC_THAW: {

And just convert XFS to use them too?

Pekka