Re: [PATCH 07/13] block: delete partitions later in del_gendisk

[Jan Kara <jack@suse.cz>]

On Thu 18-05-23 06:23:16, Christoph Hellwig wrote:
> Delay dropping the block_devices for partitions in del_gendisk until
> after the call to blk_mark_disk_dead, so that we can implementat
> notification of removed devices in blk_mark_disk_dead.
> 
> This requires splitting a lower-level drop_partition helper out of
> delete_partition and using that from del_gendisk, while having a
> common loop for the whole device and partitions that calls
> remove_inode_hash, fsync_bdev and __invalidate_device before the
> call to blk_mark_disk_dead.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good. Feel free to add:

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

								Honza

> ---
>  block/blk.h             |  2 +-
>  block/genhd.c           | 24 +++++++++++++++++++-----
>  block/partitions/core.c | 19 ++++++++++++-------
>  3 files changed, 32 insertions(+), 13 deletions(-)
> 
> diff --git a/block/blk.h b/block/blk.h
> index 45547bcf111938..4363052f90416a 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -409,7 +409,7 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
>  int bdev_del_partition(struct gendisk *disk, int partno);
>  int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
>  		sector_t length);
> -void blk_drop_partitions(struct gendisk *disk);
> +void drop_partition(struct block_device *part);
>  
>  void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors);
>  
> diff --git a/block/genhd.c b/block/genhd.c
> index a744daeed55318..bd4c4eca31363e 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -615,6 +615,8 @@ EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
>  void del_gendisk(struct gendisk *disk)
>  {
>  	struct request_queue *q = disk->queue;
> +	struct block_device *part;
> +	unsigned long idx;
>  
>  	might_sleep();
>  
> @@ -623,16 +625,28 @@ void del_gendisk(struct gendisk *disk)
>  
>  	disk_del_events(disk);
>  
> +	/*
> +	 * Prevent new openers by unlinked the bdev inode, and write out
> +	 * dirty data before marking the disk dead and stopping all I/O.
> +	 */
>  	mutex_lock(&disk->open_mutex);
> -	remove_inode_hash(disk->part0->bd_inode);
> -	blk_drop_partitions(disk);
> +	xa_for_each(&disk->part_tbl, idx, part) {
> +		remove_inode_hash(part->bd_inode);
> +		fsync_bdev(part);
> +		__invalidate_device(part, true);
> +	}
>  	mutex_unlock(&disk->open_mutex);
>  
> -	fsync_bdev(disk->part0);
> -	__invalidate_device(disk->part0, true);
> -
>  	blk_mark_disk_dead(disk);
>  
> +	/*
> +	 * Drop all partitions now that the disk is marked dead.
> +	 */
> +	mutex_lock(&disk->open_mutex);
> +	xa_for_each_start(&disk->part_tbl, idx, part, 1)
> +		drop_partition(part);
> +	mutex_unlock(&disk->open_mutex);
> +
>  	if (!(disk->flags & GENHD_FL_HIDDEN)) {
>  		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
>  
> diff --git a/block/partitions/core.c b/block/partitions/core.c
> index fa5c707fe0ad2f..31ac815d77a83c 100644
> --- a/block/partitions/core.c
> +++ b/block/partitions/core.c
> @@ -263,10 +263,19 @@ struct device_type part_type = {
>  	.uevent		= part_uevent,
>  };
>  
> -static void delete_partition(struct block_device *part)
> +void drop_partition(struct block_device *part)
>  {
>  	lockdep_assert_held(&part->bd_disk->open_mutex);
>  
> +	xa_erase(&part->bd_disk->part_tbl, part->bd_partno);
> +	kobject_put(part->bd_holder_dir);
> +
> +	device_del(&part->bd_device);
> +	put_device(&part->bd_device);
> +}
> +
> +static void delete_partition(struct block_device *part)
> +{
>  	/*
>  	 * Remove the block device from the inode hash, so that it cannot be
>  	 * looked up any more even when openers still hold references.
> @@ -276,11 +285,7 @@ static void delete_partition(struct block_device *part)
>  	fsync_bdev(part);
>  	__invalidate_device(part, true);
>  
> -	xa_erase(&part->bd_disk->part_tbl, part->bd_partno);
> -	kobject_put(part->bd_holder_dir);
> -	device_del(&part->bd_device);
> -
> -	put_device(&part->bd_device);
> +	drop_partition(part);
>  }
>  
>  static ssize_t whole_disk_show(struct device *dev,
> @@ -519,7 +524,7 @@ static bool disk_unlock_native_capacity(struct gendisk *disk)
>  	return true;
>  }
>  
> -void blk_drop_partitions(struct gendisk *disk)
> +static void blk_drop_partitions(struct gendisk *disk)
>  {
>  	struct block_device *part;
>  	unsigned long idx;
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR