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From: Saranya Muruganandam <saranyamohan@google.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Yu Kuai <yukuai1@huaweicloud.com>,
	linux-block@vger.kernel.org,  Jens Axboe <axboe@kernel.dk>,
	sashal@kernel.org, Ming Lei <ming.lei@redhat.com>,
	 "yukuai (C)" <yukuai3@huawei.com>
Subject: Re: regression on BLKRRPART ioctl for EIO
Date: Thu, 4 Apr 2024 19:04:26 -0700	[thread overview]
Message-ID: <CAP9s-SrXqgWv4rF3EGRahtuwKU7yJFaoOcSROgrbFkhaWLEVsg@mail.gmail.com> (raw)
In-Reply-To: <20240320015134.GA14267@lst.de>

Hi Christoph,
Apologies for the delay.

Thanks a ton for your patch! Your patch solution works for me.
I sent https://lore.kernel.org/all/20240405014253.748627-1-saranyamohan@google.com/
for the block layer patch
and https://lore.kernel.org/all/20240405015657.751659-1-saranyamohan@google.com/
for the blktest added.

Once I get confirmation that they look good, I have the changes for
the older LTS which I can share.
This patch doesn't cleanly apply but your idea of flagging and using
that to return errors, fixes the regression
for stable kernels like 5.10.

Thanks again.

-Saranya


On Tue, Mar 19, 2024 at 6:51 PM Christoph Hellwig <hch@lst.de> wrote:
>
> Please try the patch below:
>
> I would also relly help to have a blktsts test case to show your
> issue and verify that it is fixed.
>
> diff --git a/block/bdev.c b/block/bdev.c
> index e7adaaf1c21927..51071d371863e0 100644
> --- a/block/bdev.c
> +++ b/block/bdev.c
> @@ -645,6 +645,14 @@ static void blkdev_flush_mapping(struct block_device *bdev)
>         bdev_write_inode(bdev);
>  }
>
> +static void blkdev_put_whole(struct block_device *bdev)
> +{
> +       if (atomic_dec_and_test(&bdev->bd_openers))
> +               blkdev_flush_mapping(bdev);
> +       if (bdev->bd_disk->fops->release)
> +               bdev->bd_disk->fops->release(bdev->bd_disk);
> +}
> +
>  static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode)
>  {
>         struct gendisk *disk = bdev->bd_disk;
> @@ -663,20 +671,21 @@ static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode)
>
>         if (!atomic_read(&bdev->bd_openers))
>                 set_init_blocksize(bdev);
> -       if (test_bit(GD_NEED_PART_SCAN, &disk->state))
> -               bdev_disk_changed(disk, false);
>         atomic_inc(&bdev->bd_openers);
> +       if (test_bit(GD_NEED_PART_SCAN, &disk->state)) {
> +               /*
> +                * Only return scanning errors if we are called from conexts
> +                * that explicitly want them, e.g. the BLKRRPART ioctl.
> +                */
> +               ret = bdev_disk_changed(disk, false);
> +               if (ret && (mode & BLK_OPEN_STRICT_SCAN)) {
> +                       blkdev_put_whole(bdev);
> +                       return ret;
> +               }
> +       }
>         return 0;
>  }
>
> -static void blkdev_put_whole(struct block_device *bdev)
> -{
> -       if (atomic_dec_and_test(&bdev->bd_openers))
> -               blkdev_flush_mapping(bdev);
> -       if (bdev->bd_disk->fops->release)
> -               bdev->bd_disk->fops->release(bdev->bd_disk);
> -}
> -
>  static int blkdev_get_part(struct block_device *part, blk_mode_t mode)
>  {
>         struct gendisk *disk = part->bd_disk;
> diff --git a/block/ioctl.c b/block/ioctl.c
> index 0c76137adcaaa5..128f503828cee7 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -562,7 +562,8 @@ static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode,
>                         return -EACCES;
>                 if (bdev_is_partition(bdev))
>                         return -EINVAL;
> -               return disk_scan_partitions(bdev->bd_disk, mode);
> +               return disk_scan_partitions(bdev->bd_disk,
> +                               mode | BLK_OPEN_STRICT_SCAN);
>         case BLKTRACESTART:
>         case BLKTRACESTOP:
>         case BLKTRACETEARDOWN:
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index f9b87c39cab047..272ce42f297cfe 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -128,6 +128,8 @@ typedef unsigned int __bitwise blk_mode_t;
>  #define BLK_OPEN_WRITE_IOCTL   ((__force blk_mode_t)(1 << 4))
>  /* open is exclusive wrt all other BLK_OPEN_WRITE opens to the device */
>  #define BLK_OPEN_RESTRICT_WRITES       ((__force blk_mode_t)(1 << 5))
> +/* return partition scanning errors */
> +#define BLK_OPEN_STRICT_SCAN   ((__force blk_mode_t)(1 << 5))
>
>  struct gendisk {
>         /*

      reply	other threads:[~2024-04-05  2:04 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-07  4:28 regression on BLKRRPART ioctl for EIO Saranya Muruganandam
2024-02-12 15:44 ` Christoph Hellwig
     [not found]   ` <CAP9s-Sr3_GVYBv-XObPRC9L27jJoQqX40d8g3gysEmy6VdQS1Q@mail.gmail.com>
2024-02-13  4:01     ` Saranya Muruganandam
2024-02-27  2:38       ` Saranya Muruganandam
2024-02-27  3:13         ` Yu Kuai
2024-03-07 18:14           ` Saranya Muruganandam
2024-03-08 16:32             ` Christoph Hellwig
2024-03-20  0:20               ` Saranya Muruganandam
2024-03-20  1:51                 ` Christoph Hellwig
2024-04-05  2:04                   ` Saranya Muruganandam [this message]

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