From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>, Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
Naohiro Aota <naohiro.aota@wdc.com>,
linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 5/9] block: change the refcounting for partitions
Date: Thu, 22 Jul 2021 16:41:28 +0800 [thread overview]
Message-ID: <YPkvONK78vIEMrMI@T590> (raw)
In-Reply-To: <20210722075402.983367-6-hch@lst.de>
On Thu, Jul 22, 2021 at 09:53:58AM +0200, Christoph Hellwig wrote:
> Instead of acquiring an inode reference on open make sure partitions
> always hold device model references to the disk while alive, and switch
> open to grab only a device model reference to the opened block device.
> If that is a partition the disk reference is transitively held by the
> partition already.
> ---
> block/partitions/core.c | 9 ++++++-
> fs/block_dev.c | 60 ++++++++++++++++-------------------------
> 2 files changed, 31 insertions(+), 38 deletions(-)
>
> diff --git a/block/partitions/core.c b/block/partitions/core.c
> index 09c58a110a89..4f7a1a9cd544 100644
> --- a/block/partitions/core.c
> +++ b/block/partitions/core.c
> @@ -261,6 +261,7 @@ static void part_release(struct device *dev)
> {
> if (MAJOR(dev->devt) == BLOCK_EXT_MAJOR)
> blk_free_ext_minor(MINOR(dev->devt));
> + put_disk(dev_to_bdev(dev)->bd_disk);
> bdput(dev_to_bdev(dev));
> }
>
> @@ -349,9 +350,13 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
> if (xa_load(&disk->part_tbl, partno))
> return ERR_PTR(-EBUSY);
>
> + /* ensure we always have a reference to the whole disk */
> + get_device(disk_to_dev(disk));
> +
> + err = -ENOMEM;
> bdev = bdev_alloc(disk, partno);
> if (!bdev)
> - return ERR_PTR(-ENOMEM);
> + goto out_put_disk;
>
> bdev->bd_start_sect = start;
> bdev_set_nr_sectors(bdev, len);
> @@ -420,6 +425,8 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
> device_del(pdev);
> out_put:
> put_device(pdev);
> +out_put_disk:
> + put_disk(disk);
put_disk() is only needed for failure of bdev_alloc(). Once bdev->bd_device
is initialized, the disk reference will be dropped via part_release().
Thanks,
Ming
next prev parent reply other threads:[~2021-07-22 8:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-22 7:53 fixes and cleanups for block_device refcounting v2 Christoph Hellwig
2021-07-22 7:53 ` [PATCH 1/9] block: delay freeing the gendisk Christoph Hellwig
2021-07-22 7:53 ` [PATCH 2/9] block: assert the locking state in delete_partition Christoph Hellwig
2021-07-22 18:38 ` Chaitanya Kulkarni
2021-07-22 7:53 ` [PATCH 3/9] block: unhash the whole device inode earlier Christoph Hellwig
2021-07-22 8:19 ` Ming Lei
2021-07-22 13:12 ` Christoph Hellwig
2021-07-22 7:53 ` [PATCH 4/9] block: allocate bd_meta_info later in add_partitions Christoph Hellwig
2021-07-22 8:32 ` Ming Lei
2021-07-22 7:53 ` [PATCH 5/9] block: change the refcounting for partitions Christoph Hellwig
2021-07-22 8:41 ` Ming Lei [this message]
2021-07-22 13:12 ` Christoph Hellwig
2021-07-22 7:53 ` [PATCH 6/9] btrfs: store a block_device in struct btrfs_ordered_extent Christoph Hellwig
2021-07-22 12:58 ` David Sterba
2021-07-22 13:04 ` Christoph Hellwig
2021-07-22 7:54 ` [PATCH 7/9] loop: don't grab a reference to the block device Christoph Hellwig
2021-07-22 8:57 ` Ming Lei
2021-07-22 18:40 ` Chaitanya Kulkarni
2021-07-22 7:54 ` [PATCH 8/9] block: remove bdgrab Christoph Hellwig
2021-07-22 7:54 ` [PATCH 9/9] block: remove bdput Christoph Hellwig
2021-07-22 18:40 ` Chaitanya Kulkarni
2021-07-28 1:39 ` fixes and cleanups for block_device refcounting v2 Jens Axboe
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