Re: [PATCH v4 00/21] btrfs: support idmapped mounts

From: Christian Brauner <christian.brauner@ubuntu.com>
To: David Sterba <dsterba@suse.com>
Cc: Christoph Hellwig <hch@lst.de>, Chris Mason <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-btrfs@vger.kernel.org,
	Christian Brauner <brauner@kernel.org>
Subject: Re: [PATCH v4 00/21] btrfs: support idmapped mounts
Date: Mon, 2 Aug 2021 14:28:27 +0200	[thread overview]
Message-ID: <20210802122827.aomsh5i3rljgm2r3@wittgenstein> (raw)
In-Reply-To: <20210727104900.829215-1-brauner@kernel.org>

On Tue, Jul 27, 2021 at 12:48:39PM +0200, Christian Brauner wrote:
> From: Christian Brauner <christian.brauner@ubuntu.com>
> 
> Hey everyone,
> 
> /* v4 */
> Rename new helper to lookup_one() and add new Reviewed-bys.
> 
> This series enables the creation of idmapped mounts on btrfs. On the list of
> filesystems btrfs was pretty high-up and requested quite often from userspace
> (cf. [1]). This series requires just a few changes to the vfs for specific
> lookup helpers that btrfs relies on to perform permission checking when looking
> up an inode. The changes are required to port some other filesystem as well.
> 
> The conversion of the necessary btrfs internals was fairly straightforward. No
> invasive changes were needed. I've decided to split up the patchset into very
> small individual patches. This hopefully makes the series more readable and
> fairly easy to review. The overall changeset is quite small.
> 
> All non-filesystem wide ioctls that peform permission checking based on inodes
> can be supported on idmapped mounts. There are really just a few restrictions.
> This should really only affect the deletion of subvolumes by subvolume id which
> can be used to delete any subvolume in the filesystem even though the caller
> might not even be able to see the subvolume under their mount. Other than that
> behavior on idmapped and non-idmapped mounts is identical for all enabled
> ioctls. People interested in idmappings on idmapped mounts should read [2].
> 
> The changeset has an associated new testsuite specific to btrfs. The
> core vfs operations that btrfs implements are covered by the generic
> idmapped mount testsuite. For the ioctls a new testsuite was added. It
> is sent alongside this patchset for ease of review but will very likely
> be merged independent of it.
> 
> All patches are based on v5.14-rc3.
> 
> The series can be pulled from:
> https://git.kernel.org/brauner/h/fs.idmapped.btrfs
> https://github.com/brauner/linux/tree/fs.idmapped.btrfs
> 
> The xfstests can be pulled from:
> https://git.kernel.org/brauner/xfstests-dev/h/fs.idmapped.btrfs
> https://github.com/brauner/xfstests/tree/fs.idmapped.btrfs
> 
> Note, the new btrfs xfstests patch is on top of a branch of mine
> containing a few more preliminary patches. So if you want to run the
> tests, please simply pull the branch and build from there.
> 
> The series has been tested with xfstests including the newly added btrfs
> specific test. All tests pass.
> There were three unrelated failures that I observed: btrfs/219,
> btrfs/2020 and btrfs/235. All three also fail on earlier kernels
> without the patch series applied.

Hey David,

Sorry to ping, could I answer the outstanding questions you had and are
you okay with this series?

Christian