From: "Darrick J. Wong" <djwong@kernel.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: aalbersh@redhat.com, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, fsverity@lists.linux.dev
Subject: Re: [PATCH 27/29] xfs: make it possible to disable fsverity
Date: Tue, 2 Apr 2024 18:26:52 -0700 [thread overview]
Message-ID: <20240403012652.GE6390@frogsfrogsfrogs> (raw)
In-Reply-To: <20240402232510.GA2576@sol.localdomain>
On Tue, Apr 02, 2024 at 04:25:10PM -0700, Eric Biggers wrote:
> On Fri, Mar 29, 2024 at 05:43:06PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > Create an experimental ioctl so that we can turn off fsverity.
>
> The concept of "experimental ioctls" seems problematic. What if people start
> relying on them? Linux tends not to have "experimental" system calls, and
> probably for good reason...
They're trapped in my enormous backlog of patches. They get this
special treatment so that I can show them to developers without anyone
getting any fancy ideas about merging them. Once I get close enough to
actually consider merging it, I'll move it out from under EXPERIMENTAL.
IOWs: I'm not planning to push xfs_fs_staging.h itself to upstream ever.
> Also, what is the use case for this ioctl? Is it necessary to have this when
> userspace can already just replace a verity file with a copy that has verity
> disabled? That's less efficient, but it does not require any kernel support and
> does not require CAP_SYS_ADMIN.
No, of course it isn't needed if replacing the file is easy. That
however assumes that replacing /is/ easy.
The use case for this is: "I enabled fsverity on my backup volume so I
could detect bitrot, then the primary disk died, and when I went to
restore the primary, I got a verity error."
Being able to read known-bad corrupted contents are less bad than losing
the entire file or having to do surgery with xfs_db to turn off
fsverity.
Just for my own convenience, this would enable me to try out fsverity in
a few places while being able to undo it quickly if <cough> we end up
changing the ondisk format during review.
> And of course, if do we add this ioctl it shouldn't be XFS-specific.
Yes, this is a proof of concept. I'd lift it to fs/verity/ if you
accept the premise.
--D
> - Eric
>
next prev parent reply other threads:[~2024-04-03 1:26 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-30 0:30 [PATCHBOMB v5.5] fs-verity support for XFS Darrick J. Wong
2024-03-30 0:32 ` [PATCHSET v5.5 1/2] fs-verity: support merkle tree access by blocks Darrick J. Wong
2024-03-30 0:32 ` [PATCH 01/13] fs: add FS_XFLAG_VERITY for verity files Darrick J. Wong
2024-03-30 0:33 ` [PATCH 02/13] fsverity: pass tree_blocksize to end_enable_verity() Darrick J. Wong
2024-03-30 0:33 ` [PATCH 03/13] fsverity: support block-based Merkle tree caching Darrick J. Wong
2024-04-05 2:31 ` Eric Biggers
2024-04-24 21:25 ` Darrick J. Wong
2024-04-24 22:08 ` Eric Biggers
2024-04-25 0:27 ` Darrick J. Wong
2024-04-25 0:46 ` Eric Biggers
2024-04-25 0:53 ` Darrick J. Wong
2024-03-30 0:33 ` [PATCH 04/13] fsverity: add per-sb workqueue for post read processing Darrick J. Wong
2024-04-05 2:39 ` Eric Biggers
2024-04-24 21:33 ` Darrick J. Wong
2024-03-30 0:33 ` [PATCH 05/13] fsverity: add tracepoints Darrick J. Wong
2024-03-30 0:34 ` [PATCH 06/13] fsverity: send the level of the merkle tree block to ->read_merkle_tree_block Darrick J. Wong
2024-04-05 2:42 ` Eric Biggers
2024-04-25 0:30 ` Darrick J. Wong
2024-03-30 0:34 ` [PATCH 07/13] fsverity: pass the new tree size and block size to ->begin_enable_verity Darrick J. Wong
2024-04-05 2:46 ` Eric Biggers
2024-04-24 21:36 ` Darrick J. Wong
2024-03-30 0:34 ` [PATCH 08/13] fsverity: expose merkle tree geometry to callers Darrick J. Wong
2024-04-05 2:50 ` Eric Biggers
2024-04-25 0:45 ` Darrick J. Wong
2024-04-25 0:49 ` Eric Biggers
2024-04-25 1:01 ` Darrick J. Wong
2024-04-25 1:04 ` Eric Biggers
2024-03-30 0:35 ` [PATCH 09/13] fsverity: box up the write_merkle_tree_block parameters too Darrick J. Wong
2024-04-05 2:52 ` Eric Biggers
2024-04-25 0:46 ` Darrick J. Wong
2024-03-30 0:35 ` [PATCH 10/13] fsverity: pass the zero-hash value to the implementation Darrick J. Wong
2024-04-05 2:57 ` Eric Biggers
2024-04-24 19:02 ` Darrick J. Wong
2024-04-24 19:19 ` Eric Biggers
2024-04-24 20:23 ` Darrick J. Wong
2024-04-24 20:59 ` Eric Biggers
2024-04-24 21:43 ` Darrick J. Wong
2024-03-30 0:35 ` [PATCH 11/13] fsverity: report validation errors back to the filesystem Darrick J. Wong
2024-04-05 3:09 ` Eric Biggers
2024-04-24 18:18 ` Darrick J. Wong
2024-04-24 18:52 ` Eric Biggers
2024-04-24 19:03 ` Darrick J. Wong
2024-03-30 0:35 ` [PATCH 12/13] fsverity: remove system-wide workqueue Darrick J. Wong
2024-04-05 3:14 ` Eric Biggers
2024-04-24 18:05 ` Darrick J. Wong
2024-04-24 18:41 ` Eric Biggers
2024-04-29 10:15 ` Andrey Albershteyn
2024-04-29 16:35 ` Darrick J. Wong
2024-03-30 0:36 ` [PATCH 13/13] iomap: integrate fs-verity verification into iomap's read path Darrick J. Wong
2024-03-30 0:32 ` [PATCHSET v5.5 2/2] xfs: fs-verity support Darrick J. Wong
2024-03-30 0:36 ` [PATCH 01/29] xfs: use unsigned ints for non-negative quantities in xfs_attr_remote.c Darrick J. Wong
2024-04-02 9:51 ` Andrey Albershteyn
2024-04-02 16:25 ` Darrick J. Wong
2024-03-30 0:36 ` [PATCH 02/29] xfs: turn XFS_ATTR3_RMT_BUF_SPACE into a function Darrick J. Wong
2024-04-02 10:09 ` Andrey Albershteyn
2024-03-30 0:36 ` [PATCH 03/29] xfs: create a helper to compute the blockcount of a max sized remote value Darrick J. Wong
2024-04-02 10:09 ` Andrey Albershteyn
2024-03-30 0:37 ` [PATCH 04/29] xfs: minor cleanups of xfs_attr3_rmt_blocks Darrick J. Wong
2024-04-02 10:11 ` Andrey Albershteyn
2024-03-30 0:37 ` [PATCH 05/29] xfs: add attribute type for fs-verity Darrick J. Wong
2024-03-30 0:37 ` [PATCH 06/29] xfs: do not use xfs_attr3_rmt_hdr for remote verity value blocks Darrick J. Wong
2024-03-30 0:37 ` [PATCH 07/29] xfs: add fs-verity ro-compat flag Darrick J. Wong
2024-03-30 0:38 ` [PATCH 08/29] xfs: add inode on-disk VERITY flag Darrick J. Wong
2024-03-30 0:38 ` [PATCH 09/29] xfs: initialize fs-verity on file open and cleanup on inode destruction Darrick J. Wong
2024-03-30 0:38 ` [PATCH 10/29] xfs: don't allow to enable DAX on fs-verity sealed inode Darrick J. Wong
2024-03-30 0:38 ` [PATCH 11/29] xfs: disable direct read path for fs-verity files Darrick J. Wong
2024-03-30 0:39 ` [PATCH 12/29] xfs: widen flags argument to the xfs_iflags_* helpers Darrick J. Wong
2024-04-02 12:37 ` Andrey Albershteyn
2024-04-02 16:27 ` Darrick J. Wong
2024-03-30 0:39 ` [PATCH 13/29] xfs: add fs-verity support Darrick J. Wong
2024-04-02 8:42 ` Andrey Albershteyn
2024-04-02 16:34 ` Darrick J. Wong
2024-04-25 1:14 ` Darrick J. Wong
2024-03-30 0:39 ` [PATCH 14/29] xfs: create a per-mount shrinker for verity inodes merkle tree blocks Darrick J. Wong
2024-04-05 3:16 ` Eric Biggers
2024-04-24 17:39 ` Darrick J. Wong
2024-03-30 0:39 ` [PATCH 15/29] xfs: create an icache tag for files with cached " Darrick J. Wong
2024-03-30 0:40 ` [PATCH 16/29] xfs: shrink verity blob cache Darrick J. Wong
2024-03-30 0:40 ` [PATCH 17/29] xfs: only allow the verity iflag for regular files Darrick J. Wong
2024-04-02 12:52 ` Andrey Albershteyn
2024-03-30 0:40 ` [PATCH 18/29] xfs: don't store trailing zeroes of merkle tree blocks Darrick J. Wong
2024-03-30 0:41 ` [PATCH 19/29] xfs: use merkle tree offset as attr hash Darrick J. Wong
2024-03-30 0:41 ` [PATCH 20/29] xfs: don't bother storing merkle tree blocks for zeroed data blocks Darrick J. Wong
2024-03-30 0:41 ` [PATCH 21/29] xfs: add fs-verity ioctls Darrick J. Wong
2024-03-30 0:41 ` [PATCH 22/29] xfs: advertise fs-verity being available on filesystem Darrick J. Wong
2024-04-02 13:44 ` Andrey Albershteyn
2024-03-30 0:42 ` [PATCH 23/29] xfs: make scrub aware of verity dinode flag Darrick J. Wong
2024-03-30 0:42 ` [PATCH 24/29] xfs: teach online repair to evaluate fsverity xattrs Darrick J. Wong
2024-04-02 15:42 ` Andrey Albershteyn
2024-04-02 16:42 ` Darrick J. Wong
2024-03-30 0:42 ` [PATCH 25/29] xfs: report verity failures through the health system Darrick J. Wong
2024-04-02 16:16 ` Andrey Albershteyn
2024-03-30 0:42 ` [PATCH 26/29] xfs: clear the verity iflag when not appropriate Darrick J. Wong
2024-04-02 16:26 ` Andrey Albershteyn
2024-03-30 0:43 ` [PATCH 27/29] xfs: make it possible to disable fsverity Darrick J. Wong
2024-04-02 17:15 ` Andrey Albershteyn
2024-04-02 23:25 ` Eric Biggers
2024-04-03 1:26 ` Darrick J. Wong [this message]
2024-03-30 0:43 ` [PATCH 28/29] xfs: allow verity files to be opened even if the fsverity metadata is damaged Darrick J. Wong
2024-04-02 18:04 ` Andrey Albershteyn
2024-04-02 20:00 ` Colin Walters
2024-04-02 22:52 ` Darrick J. Wong
2024-04-02 23:45 ` Eric Biggers
2024-04-03 1:34 ` Darrick J. Wong
2024-04-03 0:10 ` Colin Walters
2024-04-03 1:39 ` Darrick J. Wong
2024-04-03 1:59 ` Dave Chinner
2024-04-03 3:19 ` Darrick J. Wong
2024-04-03 22:22 ` Dave Chinner
2024-04-03 8:35 ` Alexander Larsson
2024-03-30 0:43 ` [PATCH 29/29] xfs: enable ro-compat fs-verity flag Darrick J. Wong
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