[Devel] [PATCH RH9 2/7] dm: add find_hole infrastructure
Alexander Atanasov
alexander.atanasov at virtuozzo.com
Mon Jul 24 14:22:54 MSK 2023
On 24.07.23 11:02, Konstantin Khorenko wrote:
> Implement intermediate find_hole() on device-mapper layer. Do some simple
> checks, add new function to target_type, so any dm devices may realize it
>
> https://jira.vzint.dev/browse/PSBM-145746
> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> ---
> drivers/md/dm.c | 39 +++++++++++++++++++++++++++++++++++
> include/linux/device-mapper.h | 4 ++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index c6e16ee81281..38f810ca8829 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -480,6 +480,43 @@ static int dm_blk_ioctl(struct block_device *bdev,
> fmode_t mode,
> return r;
> }
> +static loff_t dm_find_hole(struct block_device *bdev, loff_t offset,
> int whence)
> +{
> + struct mapped_device *md = bdev->bd_disk->private_data;
> + struct dm_table *table;
> + struct dm_target *ti;
> + loff_t ret = -ENOTTY;
> + int srcu_idx;
> +
> + table = dm_get_live_table(md, &srcu_idx);
> + if (!table || !dm_table_get_size(table))
> + goto out;
> +
> + /*
> + * For now we only support devices that have a single target.
> + * But probably it is not hard to break it to a few requests to a
> different
> + * targets
> + */
> + if (table->num_targets != 1)
> + goto out;
Do we need an error message here ?
> +
> + ti = dm_table_get_target(table, 0);
> +
> + if (dm_suspended_md(md)) {
> + ret = -EAGAIN;
> + goto out;
> + }
> +
> + if (!ti->type->find_hole)
> + return -EINVAL;
mixing goto and return - on error dm_put_live_table call will be missed
> +
> + ret = ti->type->find_hole(ti, offset, whence);
> +
> +out:
> + dm_put_live_table(md, srcu_idx);
> + return ret;
> +}
> +
--
Regards,
Alexander Atanasov
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