linux-kernel - Re: [PATCH -next 1/2] block: Revert "block: Do not reread partition table on exclusively open device"

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Message-ID: <20230217110102.la3w7c6pck4pfilo@quack3>
Date:   Fri, 17 Feb 2023 12:01:02 +0100
From:   Jan Kara <jack@...e.cz>
To:     Yu Kuai <yukuai1@...weicloud.com>
Cc:     jack@...e.cz, hare@...e.de, hch@...radead.org, axboe@...nel.dk,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        yukuai3@...wei.com, yi.zhang@...wei.com, yangerkun@...wei.com
Subject: Re: [PATCH -next 1/2] block: Revert "block: Do not reread partition
 table on exclusively open device"

On Fri 17-02-23 10:21:59, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@...wei.com>
> 
> This reverts commit 36369f46e91785688a5f39d7a5590e3f07981316.
> 
> This patch can't fix the problem in a corner case that device can be
> opened exclusively after the checking and before blkdev_get_by_dev().
> We'll use a new solution to fix the problem in the next patch, and
> the new solution doesn't need to change apis.
> 
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>

Sure. Feel free to add:

Acked-by: Jan Kara <jack@...e.cz>

or Reviewed-by... whatever for the revert :)

								Honza

> ---
>  block/blk.h   |  2 +-
>  block/genhd.c |  7 ++-----
>  block/ioctl.c | 13 ++++++-------
>  3 files changed, 9 insertions(+), 13 deletions(-)
> 
> diff --git a/block/blk.h b/block/blk.h
> index f02381405311..4a166f847ffd 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -439,7 +439,7 @@ static inline void bio_release_page(struct bio *bio, struct page *page)
>  
>  struct request_queue *blk_alloc_queue(int node_id);
>  
> -int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner);
> +int disk_scan_partitions(struct gendisk *disk, fmode_t mode);
>  
>  int disk_alloc_events(struct gendisk *disk);
>  void disk_add_events(struct gendisk *disk);
> diff --git a/block/genhd.c b/block/genhd.c
> index d09d775c222a..b30d5538710c 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -356,7 +356,7 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action)
>  }
>  EXPORT_SYMBOL_GPL(disk_uevent);
>  
> -int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner)
> +int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
>  {
>  	struct block_device *bdev;
>  
> @@ -366,9 +366,6 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner)
>  		return -EINVAL;
>  	if (disk->open_partitions)
>  		return -EBUSY;
> -	/* Someone else has bdev exclusively open? */
> -	if (disk->part0->bd_holder && disk->part0->bd_holder != owner)
> -		return -EBUSY;
>  
>  	set_bit(GD_NEED_PART_SCAN, &disk->state);
>  	bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL);
> @@ -499,7 +496,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
>  
>  		bdev_add(disk->part0, ddev->devt);
>  		if (get_capacity(disk))
> -			disk_scan_partitions(disk, FMODE_READ, NULL);
> +			disk_scan_partitions(disk, FMODE_READ);
>  
>  		/*
>  		 * Announce the disk and partitions after all partitions are
> diff --git a/block/ioctl.c b/block/ioctl.c
> index 96617512982e..6dd49d877584 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -467,10 +467,10 @@ static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
>   * user space. Note the separate arg/argp parameters that are needed
>   * to deal with the compat_ptr() conversion.
>   */
> -static int blkdev_common_ioctl(struct file *file, fmode_t mode, unsigned cmd,
> -			       unsigned long arg, void __user *argp)
> +static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
> +			       unsigned int cmd, unsigned long arg,
> +			       void __user *argp)
>  {
> -	struct block_device *bdev = I_BDEV(file->f_mapping->host);
>  	unsigned int max_sectors;
>  
>  	switch (cmd) {
> @@ -528,8 +528,7 @@ static int blkdev_common_ioctl(struct file *file, fmode_t mode, unsigned cmd,
>  			return -EACCES;
>  		if (bdev_is_partition(bdev))
>  			return -EINVAL;
> -		return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL,
> -					    file);
> +		return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL);
>  	case BLKTRACESTART:
>  	case BLKTRACESTOP:
>  	case BLKTRACETEARDOWN:
> @@ -607,7 +606,7 @@ long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
>  		break;
>  	}
>  
> -	ret = blkdev_common_ioctl(file, mode, cmd, arg, argp);
> +	ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
>  	if (ret != -ENOIOCTLCMD)
>  		return ret;
>  
> @@ -676,7 +675,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
>  		break;
>  	}
>  
> -	ret = blkdev_common_ioctl(file, mode, cmd, arg, argp);
> +	ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
>  	if (ret == -ENOIOCTLCMD && disk->fops->compat_ioctl)
>  		ret = disk->fops->compat_ioctl(bdev, mode, cmd, arg);
>  
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR