From: Jan Kara <jack@suse.cz>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org, Mike Snitzer <snitzer@redhat.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jan Kara <jack@suse.com>, Josef Bacik <josef@toxicpanda.com>,
Coly Li <colyli@suse.de>,
linux-block@vger.kernel.org, Richard Weinberger <richard@nod.at>,
dm-devel@redhat.com, linux-mtd@lists.infradead.org,
Johannes Thumshirn <johannes.thumshirn@wdc.com>,
Tejun Heo <tj@kernel.org>,
xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev
Date: Wed, 25 Nov 2020 13:29:53 +0100 [thread overview]
Message-ID: <20201125122953.GH16944@quack2.suse.cz> (raw)
In-Reply-To: <20201124132751.3747337-5-hch@lst.de>
On Tue 24-11-20 14:27:10, Christoph Hellwig wrote:
> Store the frozen superblock in struct block_device to avoid the awkward
> interface that can return a sb only used a cookie, an ERR_PTR or NULL.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Some comments below...
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index d8664f5c1ff669..60492620d51866 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -548,55 +548,47 @@ EXPORT_SYMBOL(fsync_bdev);
> * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
> * actually.
> */
> -struct super_block *freeze_bdev(struct block_device *bdev)
> +int freeze_bdev(struct block_device *bdev)
> {
> struct super_block *sb;
> int error = 0;
>
> mutex_lock(&bdev->bd_fsfreeze_mutex);
> - if (++bdev->bd_fsfreeze_count > 1) {
> - /*
> - * We don't even need to grab a reference - the first call
> - * to freeze_bdev grab an active reference and only the last
> - * thaw_bdev drops it.
> - */
> - sb = get_super(bdev);
> - if (sb)
> - drop_super(sb);
> - mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return sb;
> - }
> + if (++bdev->bd_fsfreeze_count > 1)
> + goto done;
>
> sb = get_active_super(bdev);
> if (!sb)
> - goto out;
> + goto sync;
> if (sb->s_op->freeze_super)
> error = sb->s_op->freeze_super(sb);
> else
> error = freeze_super(sb);
> + deactivate_super(sb);
> +
> if (error) {
> - deactivate_super(sb);
> bdev->bd_fsfreeze_count--;
> - mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return ERR_PTR(error);
> + goto done;
> }
> - deactivate_super(sb);
> - out:
> + bdev->bd_fsfreeze_sb = sb;
> +
> +sync:
> sync_blockdev(bdev);
> +done:
> mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return sb; /* thaw_bdev releases s->s_umount */
> + return error; /* thaw_bdev releases s->s_umount */
The comment about thaw_bdev() seems to be stale? At least I don't see what
it's speaking about...
> }
> EXPORT_SYMBOL(freeze_bdev);
>
> /**
> * thaw_bdev -- unlock filesystem
> * @bdev: blockdevice to unlock
> - * @sb: associated superblock
> *
> * Unlocks the filesystem and marks it writeable again after freeze_bdev().
> */
> -int thaw_bdev(struct block_device *bdev, struct super_block *sb)
> +int thaw_bdev(struct block_device *bdev)
> {
> + struct super_block *sb;
> int error = -EINVAL;
>
> mutex_lock(&bdev->bd_fsfreeze_mutex);
> @@ -607,6 +599,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
> if (--bdev->bd_fsfreeze_count > 0)
> goto out;
>
> + sb = bdev->bd_fsfreeze_sb;
> if (!sb)
> goto out;
>
> @@ -618,7 +611,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
> bdev->bd_fsfreeze_count++;
> out:
> mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return error;
> + return 0;
But we now won't return -EINVAL if this gets called e.g. with
bd_fsfreeze_count == 0, right?
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
--
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next prev parent reply other threads:[~2020-11-25 14:53 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
2020-11-25 6:41 ` Hannes Reinecke
2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
2020-11-24 13:53 ` Matthew Wilcox
2020-11-25 6:41 ` Hannes Reinecke
2020-11-25 12:16 ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
2020-11-25 6:42 ` Hannes Reinecke
2020-11-25 12:19 ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
2020-11-25 6:07 ` Chao Yu
2020-11-25 12:29 ` Jan Kara [this message]
2020-11-25 16:22 ` Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
2020-11-25 12:31 ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 06/45] zram: remove the claim mechanism Christoph Hellwig
2020-11-25 12:37 ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 07/45] zram: do not call set_blocksize Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 08/45] loop: " Christoph Hellwig
2020-11-25 13:37 ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 09/45] dm: simplify flush_bio initialization in __send_empty_flush Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 10/45] dm: remove the block_device reference in struct mapped_device Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
2020-11-24 17:36 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl Christoph Hellwig
2020-11-24 17:37 ` Tejun Heo
2020-11-25 13:39 ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper Christoph Hellwig
2020-11-24 13:41 ` Coly Li
2020-11-24 17:37 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
2020-11-24 17:37 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 15/45] block: use put_device in put_disk Christoph Hellwig
2020-11-24 17:37 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices Christoph Hellwig
2020-11-24 17:38 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t Christoph Hellwig
2020-11-24 17:38 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid Christoph Hellwig
2020-11-24 17:38 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
2020-11-24 17:39 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 20/45] block: refactor __blkdev_put Christoph Hellwig
2020-11-24 17:41 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 21/45] block: refactor blkdev_get Christoph Hellwig
2020-11-24 18:03 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission Christoph Hellwig
2020-11-24 18:05 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 23/45] block: remove i_bdev Christoph Hellwig
2020-11-24 13:38 ` Coly Li
2020-11-24 19:37 ` Tejun Heo
2020-11-25 16:29 ` Christoph Hellwig
2020-11-25 20:19 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk Christoph Hellwig
2020-11-24 19:46 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct Christoph Hellwig
2020-11-24 21:18 ` Tejun Heo
2020-11-25 16:45 ` Christoph Hellwig
2020-11-25 20:20 ` Tejun Heo
2020-11-26 8:16 ` Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
2020-11-24 21:19 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface Christoph Hellwig
2020-11-24 21:19 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 28/45] block: simplify part_to_disk Christoph Hellwig
2020-11-24 21:20 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc Christoph Hellwig
2020-11-24 21:20 ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
2020-11-24 13:34 ` Coly Li
2020-11-25 6:10 ` Chao Yu
2020-11-24 13:27 ` [dm-devel] [PATCH 31/45] block: move disk stat accounting to struct block_device Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 32/45] block: move the start_sect field " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 33/45] block: move the partition_meta_info " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 34/45] block: move holder_dir " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 35/45] block: move make_it_fail " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 36/45] block: move the policy field " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 37/45] block: allocate struct hd_struct as part of struct bdev_inode Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device Christoph Hellwig
2020-11-24 13:32 ` Coly Li
2020-11-25 6:11 ` Chao Yu
2020-11-24 13:27 ` [dm-devel] [PATCH 39/45] block: remove the partno field from struct hd_struct Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 40/45] block: pass a block_device to blk_alloc_devt Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 41/45] block: pass a block_device to invalidate_partition Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 42/45] block: switch disk_part_iter_* to use a struct block_device Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks Christoph Hellwig
2020-11-25 6:12 ` Chao Yu
2020-11-24 13:27 ` [dm-devel] [PATCH 44/45] block: merge struct block_device and struct hd_struct Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 45/45] block: stop using bdget_disk for partition 0 Christoph Hellwig
2020-11-28 16:14 [dm-devel] merge struct block_device and struct hd_struct v4 Christoph Hellwig
2020-11-28 16:14 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
2020-11-30 17:55 ` Darrick J. Wong
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