From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id E654E426837 for ; Fri, 25 Aug 2023 04:21:52 +0200 (CEST) Date: Fri, 25 Aug 2023 02:58:43 +0100 From: Al Viro To: Jan Kara Message-ID: <20230825015843.GB95084@ZenIV> References: <20230810171429.31759-1-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230810171429.31759-1-jack@suse.cz> Sender: Al Viro Cc: Dave Kleikamp , jfs-discussion@lists.sourceforge.net, "Darrick J. Wong" , linux-nvme@lists.infradead.org, Joseph Qi , dm-devel@redhat.com, target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, Jack Wang , Alasdair Kergon , drbd-dev@lists.linbit.com, linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi@vger.kernel.org, Sergey Senozhatsky , Christoph Hellwig , xen-devel@lists.xenproject.org, Gao Xiang , Christian Borntraeger , Kent Overstreet , Sven Schnelle , linux-pm@vger.kernel.org, Mike Snitzer , Chao Yu , Joern Engel , reiserfs-devel@vger.kernel.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, David Sterba , Jaegeuk Kim , Trond Myklebust , linux-raid@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, Ted Tso , linux-mm@kvack.org, Song Liu , linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, Minchan Kim , ocfs2-devel@oss.oracle.com, Anna Schumaker , linux-fsdevel@vger.kernel.org, "Md. Haris Iqbal" , Andrew Morton , linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Subject: Re: [Drbd-dev] [PATCH v2 0/29] block: Make blkdev_get_by_*() return handle List-Id: "*Coordination* of development, patches, contributions -- *Questions* \(even to developers\) go to drbd-user, please." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Aug 11, 2023 at 01:04:31PM +0200, Jan Kara wrote: > Hello, > > this is a v2 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 yesterday as there is quite > some overlap. Patches have passed some reasonable testing - I've tested block > changes, md, dm, bcache, xfs, btrfs, ext4, swap. This obviously doesn't cover > everything so I'd like to ask respective maintainers to review / test their > changes. 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. Hmm... Completely Insane Idea(tm): how about turning that thing inside out and having your bdev_open_by... return an actual opened struct file? After all, we do that for sockets and pipes just fine and that's a whole lot hotter area. Suppose we leave blkdev_open()/blkdev_release() as-is. No need to mess with what we have for normal opened files for block devices. And have block_open_by_dev() that would find bdev, etc., same yours does and shove it into anon file. Paired with plain fput() - no need to bother with new primitives for closing. With a helper returning I_BDEV(bdev_file_inode(file)) to get from those to bdev. NOTE: I'm not suggesting replacing ->s_bdev with struct file * if we do that - we want that value cached, obviously. Just store both... Not saying it's a good idea, but... might be interesting to look into. Comments?