Re: [PATCH 1/5] block: refactor rescan_partitions

Jan Kara
2019-11-14T13:13:40Z

On Wed 06-11-19 16:14:35, Christoph Hellwig wrote:
> Split out a helper that adds one single partition, and another one
> calling that dealing with the parsed_partitions state. This makes
> it much more obvious how we clean up all state and start again when
> using the rescan label.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> block/partition-generic.c | 176 +++++++++++++++++++++-----------------
> 1 file changed, 96 insertions(+), 80 deletions(-)
>
> diff --git a/block/partition-generic.c b/block/partition-generic.c
> index aee643ce13d1..f113be069b40 100644
> --- a/block/partition-generic.c
> +++ b/block/partition-generic.c
> @@ -509,26 +509,77 @@ static bool part_zone_aligned(struct gendisk *disk,
> return true;
> }
>
> -int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
> +static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
> + struct parsed_partitions *state, int p)
> {
> - struct parsed_partitions *state = NULL;
> + sector_t size = state->parts[p].size;
> + sector_t from = state->parts[p].from;
> struct hd_struct *part;
> - int p, highest, res;
> -rescan:
> - if (state && !IS_ERR(state)) {
> - free_partitions(state);
> - state = NULL;
> +
> + if (!size)
> + return true;
> +
> + if (from >= get_capacity(disk)) {
> + printk(KERN_WARNING
> + "%s: p%d start %llu is beyond EOD, ",
> + disk->disk_name, p, (unsigned long long) from);
> + if (disk_unlock_native_capacity(disk))
> + return false;
> + return true;
> }
>
> - res = drop_partitions(disk, bdev);
> - if (res)
> - return res;
> + if (from + size > get_capacity(disk)) {
> + printk(KERN_WARNING
> + "%s: p%d size %llu extends beyond EOD, ",
> + disk->disk_name, p, (unsigned long long) size);
>
> - if (disk->fops->revalidate_disk)
> - disk->fops->revalidate_disk(disk);
> - check_disk_size_change(disk, bdev, true);
> - bdev->bd_invalidated = 0;
> - if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
> + if (disk_unlock_native_capacity(disk))
> + return false;
> +
> + /*
> + * We can not ignore partitions of broken tables created by for
> + * example camera firmware, but we limit them to the end of the
> + * disk to avoid creating invalid block devices.
> + */
> + size = get_capacity(disk) - from;
> + }
> +
> + /*
> + * On a zoned block device, partitions should be aligned on the device
> + * zone size (i.e. zone boundary crossing not allowed). Otherwise,
> + * resetting the write pointer of the last zone of one partition may
> + * impact the following partition.
> + */
> + if (bdev_is_zoned(bdev) && !part_zone_aligned(disk, bdev, from, size)) {
> + printk(KERN_WARNING
> + "%s: p%d start %llu+%llu is not zone aligned\n",
> + disk->disk_name, p, (unsigned long long) from,
> + (unsigned long long) size);
> + return true;
> + }
> +
> + part = add_partition(disk, p, from, size, state->parts[p].flags,
> + &state->parts[p].info);
> + if (IS_ERR(part)) {
> + printk(KERN_ERR " %s: p%d could not be added: %ld\n",
> + disk->disk_name, p, -PTR_ERR(part));
> + return true;
> + }
> +
> +#ifdef CONFIG_BLK_DEV_MD
> + if (state->parts[p].flags & ADDPART_FLAG_RAID)
> + md_autodetect_dev(part_to_dev(part)->devt);
> +#endif
> + return true;
> +}
> +
> +static int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
> +{
> + struct parsed_partitions *state;
> + int ret = -EAGAIN, p, highest;
> +
> + state = check_partition(disk, bdev);
> + if (!state)
> return 0;
> if (IS_ERR(state)) {
> /*
> @@ -540,7 +591,7 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
> printk(KERN_WARNING "%s: partition table beyond EOD, ",
> disk->disk_name);
> if (disk_unlock_native_capacity(disk))
> - goto rescan;
> + return -EAGAIN;
> }
> return -EIO;
> }
> @@ -554,7 +605,7 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
> "%s: partition table partially beyond EOD, ",
> disk->disk_name);
> if (disk_unlock_native_capacity(disk))
> - goto rescan;
> + goto out_free_state;
> }
>
> /* tell userspace that the media / partition table may have changed */
> @@ -571,72 +622,37 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
> disk_expand_part_tbl(disk, highest);
>
> /* add partitions */
> - for (p = 1; p < state->limit; p++) {
> - sector_t size, from;
> -
> - size = state->parts[p].size;
> - if (!size)
> - continue;
> -
> - from = state->parts[p].from;
> - if (from >= get_capacity(disk)) {
> - printk(KERN_WARNING
> - "%s: p%d start %llu is beyond EOD, ",
> - disk->disk_name, p, (unsigned long long) from);
> - if (disk_unlock_native_capacity(disk))
> - goto rescan;
> - continue;
> - }
> + for (p = 1; p < state->limit; p++)
> + if (!blk_add_partition(disk, bdev, state, p))
> + goto out_free_state;
>
> - if (from + size > get_capacity(disk)) {
> - printk(KERN_WARNING
> - "%s: p%d size %llu extends beyond EOD, ",
> - disk->disk_name, p, (unsigned long long) size);
> -
> - if (disk_unlock_native_capacity(disk)) {
> - /* free state and restart */
> - goto rescan;
> - } else {
> - /*
> - * we can not ignore partitions of broken tables
> - * created by for example camera firmware, but
> - * we limit them to the end of the disk to avoid
> - * creating invalid block devices
> - */
> - size = get_capacity(disk) - from;
> - }
> - }
> + ret = 0;
> +out_free_state:
> + free_partitions(state);
> + return ret;
> +}
>
> - /*
> - * On a zoned block device, partitions should be aligned on the
> - * device zone size (i.e. zone boundary crossing not allowed).
> - * Otherwise, resetting the write pointer of the last zone of
> - * one partition may impact the following partition.
> - */
> - if (bdev_is_zoned(bdev) &&
> - !part_zone_aligned(disk, bdev, from, size)) {
> - printk(KERN_WARNING
> - "%s: p%d start %llu+%llu is not zone aligned\n",
> - disk->disk_name, p, (unsigned long long) from,
> - (unsigned long long) size);
> - continue;
> - }
> +int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
> +{
> + int ret;
>
> - part = add_partition(disk, p, from, size,
> - state->parts[p].flags,
> - &state->parts[p].info);
> - if (IS_ERR(part)) {
> - printk(KERN_ERR " %s: p%d could not be added: %ld\n",
> - disk->disk_name, p, -PTR_ERR(part));
> - continue;
> - }
> -#ifdef CONFIG_BLK_DEV_MD
> - if (state->parts[p].flags & ADDPART_FLAG_RAID)
> - md_autodetect_dev(part_to_dev(part)->devt);
> -#endif
> - }
> - free_partitions(state);
> - return 0;
> +rescan:
> + ret = drop_partitions(disk, bdev);
> + if (ret)
> + return ret;
> +
> + if (disk->fops->revalidate_disk)
> + disk->fops->revalidate_disk(disk);
> + check_disk_size_change(disk, bdev, true);
> + bdev->bd_invalidated = 0;
> +
> + if (!get_capacity(disk))
> + return 0;
> +
> + ret = blk_add_partitions(disk, bdev);
> + if (ret == -EAGAIN)
> + goto rescan;
> + return ret;
> }
>
> int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
> --
> 2.20.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR