[PATCH 3/7] partition: allow to reparse a partition table

[Marco Felsch]

On 24-02-15, Sascha Hauer wrote:
> The partition table of a block device may change when it is written to.
> Allow to reparse the partition table when this happens.
> This is easy when none of the partitions is opened, in that case just
> remove the old partitions and call parse_partition_table() again.
> When a partition is opened (including mounted) we can't remove it. In
> that case continue with the old partition table and print a warning.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>

Just two nits, to make cdev access more opaque.

> ---
>  common/partitions.c | 20 ++++++++++++++++++++
>  include/disks.h     |  1 +
>  2 files changed, 21 insertions(+)
> 
> diff --git a/common/partitions.c b/common/partitions.c
> index 78b68276c3..cfcd0e080b 100644
> --- a/common/partitions.c
> +++ b/common/partitions.c
> @@ -154,6 +154,26 @@ int parse_partition_table(struct block_device *blk)
>  	return rc;
>  }
>  
> +int reparse_partition_table(struct block_device *blk)
> +{
> +	struct cdev *cdev = &blk->cdev;
> +	struct cdev *c, *tmp;
> +
> +	list_for_each_entry(c, &cdev->partitions, partition_entry) {
> +		if (c->open) {

		if (cdev_is_open(c))

> +			pr_warn("%s is busy, will continue to use old partition table\n", c->name);
> +			return -EBUSY;
> +		}
> +	}
> +
> +	list_for_each_entry_safe(c, tmp, &cdev->partitions, partition_entry) {
> +		if (c->flags & DEVFS_PARTITION_FROM_TABLE)

		if (cdev_flag_set(c, DEVFS_PARTITION_FROM_TABLE))

> +			cdevfs_del_partition(c);
> +	}
> +
> +	return parse_partition_table(blk);
> +}
> +
>  int partition_parser_register(struct partition_parser *p)
>  {
>  	list_add_tail(&p->list, &partition_parser_list);
> diff --git a/include/disks.h b/include/disks.h
> index 1ca7063c54..ccb50d3ce9 100644
> --- a/include/disks.h
> +++ b/include/disks.h
> @@ -24,5 +24,6 @@ struct partition_entry {
>  } __attribute__ ((packed));
>  
>  extern int parse_partition_table(struct block_device*);
> +int reparse_partition_table(struct block_device *blk);
>  
>  #endif /* DISKS_H */
> -- 
> 2.39.2
> 
> 
>