[v3,0/29] block: Make blkdev_get_by_*() return handle

Hello,

this is a v3 of the patch series which implements the idea of blkdev_get_by_*()
calls returning bdev_handle which is then passed to blkdev_put() [1]. This
makes the get and put calls for bdevs more obviously matching and allows us to
propagate context from get to put without having to modify all the users
(again!). In particular I need to propagate used open flags to blkdev_put() to
be able count writeable opens and add support for blocking writes to mounted
block devices. I'll send that series separately.

The series is based on Christian's vfs tree as of today as there is quite
some overlap. Patches have passed some reasonable testing - I've tested block
changes, md, dm, bcache, xfs, btrfs, ext4, swap. More testing or review is
always welcome. Thanks! I've pushed out the full branch to:

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdev_handle

to ease review / testing. Since there were not many comments for v2 and
Christoph has acked the series I think we should start discussing how to merge
the series. Most collisions with this series seem to happen in the filesystems
area so VFS tree would seem as the least painful way to merge this. Jens,
are you OK with that?

Changes since v2:
* Rebased on top of current vfs tree
* Added some acks
* Reflected minor nits from Christoph
* Added missing conversion of blkdev_put() calls in cramfs and erofs
* Fixed possible leak of bdev handle in xfs if logdev is the same as fs dev

Changes since v1:
* Rebased on top of current vfs tree
* Renamed final functions to bdev_open_by_*() and bdev_release()
* Fixed detection of exclusive open in blkdev_ioctl() and blkdev_fallocate()
* Fixed swap conversion to properly reinitialize swap_info->bdev_handle
* Fixed xfs conversion to not oops with rtdev without logdev
* Couple other minor fixups

								Honza

[1] https://lore.kernel.org/all/ZJGNsVDhZx0Xgs2H@infradead.org

CC: Alasdair Kergon <agk@redhat.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Anna Schumaker <anna@kernel.org>
CC: Chao Yu <chao@kernel.org>
CC: Christian Borntraeger <borntraeger@linux.ibm.com>
CC: Coly Li <colyli@suse.de
CC: "Darrick J. Wong" <djwong@kernel.org>
CC: Dave Kleikamp <shaggy@kernel.org>
CC: David Sterba <dsterba@suse.com>
CC: dm-devel@redhat.com
CC: drbd-dev@lists.linbit.com
CC: Gao Xiang <xiang@kernel.org>
CC: Jack Wang <jinpu.wang@ionos.com>
CC: Jaegeuk Kim <jaegeuk@kernel.org>
CC: jfs-discussion@lists.sourceforge.net
CC: Joern Engel <joern@lazybastard.org>
CC: Joseph Qi <joseph.qi@linux.alibaba.com>
CC: Kent Overstreet <kent.overstreet@gmail.com>
CC: linux-bcache@vger.kernel.org
CC: linux-btrfs@vger.kernel.org
CC: linux-erofs@lists.ozlabs.org
CC: <linux-ext4@vger.kernel.org>
CC: linux-f2fs-devel@lists.sourceforge.net
CC: linux-mm@kvack.org
CC: linux-mtd@lists.infradead.org
CC: linux-nfs@vger.kernel.org
CC: linux-nilfs@vger.kernel.org
CC: linux-nvme@lists.infradead.org
CC: linux-pm@vger.kernel.org
CC: linux-raid@vger.kernel.org
CC: linux-s390@vger.kernel.org
CC: linux-scsi@vger.kernel.org
CC: linux-xfs@vger.kernel.org
CC: "Md. Haris Iqbal" <haris.iqbal@ionos.com>
CC: Mike Snitzer <snitzer@kernel.org>
CC: Minchan Kim <minchan@kernel.org>
CC: ocfs2-devel@oss.oracle.com
CC: reiserfs-devel@vger.kernel.org
CC: Sergey Senozhatsky <senozhatsky@chromium.org>
CC: Song Liu <song@kernel.org>
CC: Sven Schnelle <svens@linux.ibm.com>
CC: target-devel@vger.kernel.org
CC: Ted Tso <tytso@mit.edu>
CC: Trond Myklebust <trond.myklebust@hammerspace.com>
CC: xen-devel@lists.xenproject.org

Previous versions:
Link: http://lore.kernel.org/r/20230629165206.383-1-jack@suse.cz # v1
Link: http://lore.kernel.org/r/20230810171429.31759-1-jack@suse.cz # v2

On Wed, Aug 23, 2023 at 12:48:27PM +0200, Jan Kara wrote:
> Convert hibernation code to use bdev_open_by_dev().
> 
> CC: linux-pm@vger.kernel.org
> Acked-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Rafael J. Wysocki <rafael@kernel.org>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---

Looks good to me,
Acked-by: Christian Brauner <brauner@kernel.org>

On Wed, Aug 23, 2023 at 12:48:11PM +0200, Jan Kara wrote:
> Hello,
> 
> this is a v3 of the patch series which implements the idea of blkdev_get_by_*()
> calls returning bdev_handle which is then passed to blkdev_put() [1]. This
> makes the get and put calls for bdevs more obviously matching and allows us to
> propagate context from get to put without having to modify all the users
> (again!). In particular I need to propagate used open flags to blkdev_put() to
> be able count writeable opens and add support for blocking writes to mounted
> block devices. I'll send that series separately.
> 
> The series is based on Christian's vfs tree as of today as there is quite
> some overlap. Patches have passed some reasonable testing - I've tested block
> changes, md, dm, bcache, xfs, btrfs, ext4, swap. More testing or review is
> always welcome. Thanks! I've pushed out the full branch to:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdev_handle
> 
> to ease review / testing. Since there were not many comments for v2 and
> Christoph has acked the series I think we should start discussing how to merge
> the series. Most collisions with this series seem to happen in the filesystems
> area so VFS tree would seem as the least painful way to merge this. Jens,

I really do like this series especially struct bdev_handle and moving
the mode bits in there. I'll happily take this. So far there have only
been minor things that can easily be fixed.

On Fri 25-08-23 15:32:47, Christian Brauner wrote:
> On Wed, Aug 23, 2023 at 12:48:11PM +0200, Jan Kara wrote:
> > Hello,
> > 
> > this is a v3 of the patch series which implements the idea of blkdev_get_by_*()
> > calls returning bdev_handle which is then passed to blkdev_put() [1]. This
> > makes the get and put calls for bdevs more obviously matching and allows us to
> > propagate context from get to put without having to modify all the users
> > (again!). In particular I need to propagate used open flags to blkdev_put() to
> > be able count writeable opens and add support for blocking writes to mounted
> > block devices. I'll send that series separately.
> > 
> > The series is based on Christian's vfs tree as of today as there is quite
> > some overlap. Patches have passed some reasonable testing - I've tested block
> > changes, md, dm, bcache, xfs, btrfs, ext4, swap. More testing or review is
> > always welcome. Thanks! I've pushed out the full branch to:
> > 
> > git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdev_handle
> > 
> > to ease review / testing. Since there were not many comments for v2 and
> > Christoph has acked the series I think we should start discussing how to merge
> > the series. Most collisions with this series seem to happen in the filesystems
> > area so VFS tree would seem as the least painful way to merge this. Jens,
> 
> I really do like this series especially struct bdev_handle and moving
> the mode bits in there. I'll happily take this. So far there have only
> been minor things that can easily be fixed.

Thanks. Since Al is fine with just doing a potential conversion to 'struct
file' as a handle on top of this series (it will be dumb Coccinelle
replacement) I think we can go ahead with the series as is. As you said
there will be some conflicts in btrfs and I've learned about f2fs conflicts
as well so I can rebase & repost the series on top of rc1 to make life
easier for you.

								Honza

> replacement) I think we can go ahead with the series as is. As you said
> there will be some conflicts in btrfs and I've learned about f2fs conflicts
> as well so I can rebase & repost the series on top of rc1 to make life
> easier for you.

That is be much appreciated. Thank you!

On Wed 27-09-23 18:21:19, Christian Brauner wrote:
> On Wed, 27 Sep 2023 11:34:07 +0200, Jan Kara wrote:
> > Create struct bdev_handle that contains all parameters that need to be
> > passed to blkdev_put() and provide bdev_open_* functions that return
> > this structure instead of plain bdev pointer. This will eventually allow
> > us to pass one more argument to blkdev_put() (renamed to bdev_release())
> > without too much hassle.
> > 
> > 
> > [...]
> 
> > to ease review / testing. Christian, can you pull the patches to your tree
> > to get some exposure in linux-next as well? Thanks!
> 
> Yep. So I did it slighly differently. I pulled in the btrfs prereqs and
> then applied your series on top of it so we get all the Link: tags right.
> I'm running tests right now. Please double-check.

Thanks for picking patches up! I've checked the branch and it looks good to
me. 

								Honza

> 
> ---
> 
> Applied to the vfs.super branch of the vfs/vfs.git tree.
> Patches in the vfs.super branch should appear in linux-next soon.
> 
> Please report any outstanding bugs that were missed during review in a
> new review to the original patch series allowing us to drop it.
> 
> It's encouraged to provide Acked-bys and Reviewed-bys even though the
> patch has now been applied. If possible patch trailers will be updated.
> 
> Note that commit hashes shown below are subject to change due to rebase,
> trailer updates or similar. If in doubt, please check the listed branch.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
> branch: vfs.super
> 
> [01/29] block: Provide bdev_open_* functions
>        https://git.kernel.org/vfs/vfs/c/b7c828aa0b3c
> [02/29] block: Use bdev_open_by_dev() in blkdev_open()
>         https://git.kernel.org/vfs/vfs/c/d4e36f27b45a
> [03/29] block: Use bdev_open_by_dev() in disk_scan_partitions() and blkdev_bszset()
>         https://git.kernel.org/vfs/vfs/c/5f9bd6764c7a
> [04/29] drdb: Convert to use bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/0220ca8e443d
> [05/29] pktcdvd: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/7af10b889789
> [06/29] rnbd-srv: Convert to use bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/3d27892a4be7
> [07/29] xen/blkback: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/26afb0ed10b3
> [08/29] zram: Convert to use bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/efc8e3f4c6dc
> [09/29] bcache: Convert to bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/dc893f51d24a
> [10/29] dm: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/80c2267c6d07
> [11/29] md: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/15db36126ca6
> [12/29] mtd: block2mtd: Convert to bdev_open_by_dev/path()
>         https://git.kernel.org/vfs/vfs/c/4c27234bf3ce
> [13/29] nvmet: Convert to bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/70cffddcc300
> [14/29] s390/dasd: Convert to bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/5581d03457f8
> [15/29] scsi: target: Convert to bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/43de7d844d47
> [16/29] PM: hibernate: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/105ea4a2fd18
> [17/29] PM: hibernate: Drop unused snapshot_test argument
>         https://git.kernel.org/vfs/vfs/c/b589a66e3688
> [18/29] mm/swap: Convert to use bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/615af8e29233
> [19/29] fs: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/5173192bcfe6
> [20/29] btrfs: Convert to bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/8cf64782764f
> [21/29] erofs: Convert to use bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/4d41880bf249
> [22/29] ext4: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/f7507612395e
> [23/29] f2fs: Convert to bdev_open_by_dev/path()
>         https://git.kernel.org/vfs/vfs/c/d9ff8e3b6498
> [24/29] jfs: Convert to bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/459dc6376338
> [25/29] nfs/blocklayout: Convert to use bdev_open_by_dev/path()
>         https://git.kernel.org/vfs/vfs/c/5b1df9a40929
> [26/29] ocfs2: Convert to use bdev_open_by_dev()
>         https://git.kernel.org/vfs/vfs/c/b6b95acbd943
> [27/29] reiserfs: Convert to bdev_open_by_dev/path()
>         https://git.kernel.org/vfs/vfs/c/7e3615ff6119
> [28/29] xfs: Convert to bdev_open_by_path()
>         https://git.kernel.org/vfs/vfs/c/176ccb99e207
> [29/29] block: Remove blkdev_get_by_*() functions
>         https://git.kernel.org/vfs/vfs/c/953863a5a2ff