From: "Darrick J. Wong" <djwong@kernel.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Andrey Albershteyn <aalbersh@redhat.com>,
fsverity@lists.linux.dev, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, chandan.babu@oracle.com,
ebiggers@kernel.org
Subject: Re: [PATCH v5 11/24] xfs: add XBF_VERITY_SEEN xfs_buf flag
Date: Mon, 11 Mar 2024 19:45:07 -0700 [thread overview]
Message-ID: <20240312024507.GY1927156@frogsfrogsfrogs> (raw)
In-Reply-To: <20240311152505.GR1927156@frogsfrogsfrogs>
On Mon, Mar 11, 2024 at 08:25:05AM -0700, Darrick J. Wong wrote:
<snip>
> <nod> The latest version of this tries to avoid letting reclaim take the
> top of the tree. Logically this makes sense to me to reduce read verify
> latency, but I was hoping Eric or Andrey or someone with more
> familiarity with fsverity would chime in on whether or not that made
> sense.
>
> > > > Also -- the fsverity block interfaces pass in a "u64 pos" argument. Was
> > > > that done because merkle trees may some day have more than 2^32 blocks
> > > > in them? That won't play well with things like xarrays on 32-bit
> > > > machines.
> > > >
> > > > (Granted we've been talking about deprecating XFS on 32-bit for a while
> > > > now but we're not the whole world)
> > > >
> > > > > i.e.
> > > > >
> > > > > p = xa_load(key);
> > > > > if (p)
> > > > > return p;
> > > > >
> > > > > xfs_attr_get(key);
> > > > > if (!args->value)
> > > > > /* error */
> > > > >
> > > > > /*
> > > > > * store the current value, freeing any old value that we
> > > > > * replaced at this key. Don't care about failure to store,
> > > > > * this is optimistic caching.
> > > > > */
> > > > > p = xa_store(key, args->value, GFP_NOFS);
> > > > > if (p)
> > > > > kvfree(p);
> > > > > return args->value;
> > > >
> > > > Attractive. Will have to take a look at that tomorrow.
> > >
> > > Done. I think. Not sure that I actually got all the interactions
> > > between the shrinker and the xarray correct though. KASAN and lockdep
> > > don't have any complaints running fstests, so that's a start.
> > >
> > > https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=fsverity-cleanups-6.9_2024-03-09
> >
> > My initial impression is "over-engineered".
>
> Overly focused on unfamiliar data structures -- I've never built
> anything with an xarray before.
>
> > I personally would have just allocated the xattr value buffer with a
> > little extra size and added all the external cache information (a
> > reference counter is all we need as these are fixed sized blocks) to
> > the tail of the blob we actually pass to fsverity.
>
> Oho, that's a good idea. I didn't like the separate allocation anyway.
> Friday was mostly chatting with willy and trying to make sure I got the
> xarray access patterns correct.
>
> > If we tag the
> > inode in the radix tree as having verity blobs that can be freed, we
> > can then just extend the existing fs sueprblock shrinker callout to
> > also walk all the verity inodes with cached data to try to reclaim
> > some objects...
>
> This too is a wonderful suggestion -- use the third radix tree tag to
> mark inodes with extra incore caches that can be reclaimed, then teach
> xfs_reclaim_inodes_{nr,count} to scan them. Allocating a per-inode
> shrinker was likely to cause problems with flooding debugfs with too
> many knobs anyway.
>
> > But, if a generic blob cache is what it takes to move this forwards,
> > so be it.
>
> Not necessarily. ;)
And here's today's branch, with xfs_blobcache.[ch] removed and a few
more cleanups:
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/tag/?h=fsverity-cleanups-6.9_2024-03-11
--D
>
> --D
>
> > -Dave.
> > --
> > Dave Chinner
> > david@fromorbit.com
> >
>
next prev parent reply other threads:[~2024-03-12 2:45 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-04 19:10 [PATCH v5 00/24] fs-verity support for XFS Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 01/24] fsverity: remove hash page spin lock Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 02/24] xfs: add parent pointer support to attribute code Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 03/24] xfs: define parent pointer ondisk extended attribute format Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 04/24] xfs: add parent pointer validator functions Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 05/24] fs: add FS_XFLAG_VERITY for verity files Andrey Albershteyn
2024-03-04 22:35 ` Eric Biggers
2024-03-07 21:39 ` Darrick J. Wong
2024-03-07 22:06 ` Eric Biggers
2024-03-04 19:10 ` [PATCH v5 06/24] fsverity: pass tree_blocksize to end_enable_verity() Andrey Albershteyn
2024-03-05 0:52 ` Eric Biggers
2024-03-06 16:30 ` Darrick J. Wong
2024-03-07 22:02 ` Eric Biggers
2024-03-08 3:46 ` Darrick J. Wong
2024-03-08 4:40 ` Eric Biggers
2024-03-11 22:38 ` Darrick J. Wong
2024-03-12 15:13 ` David Hildenbrand
2024-03-12 15:33 ` David Hildenbrand
2024-03-12 16:44 ` Darrick J. Wong
2024-03-13 12:29 ` David Hildenbrand
2024-03-13 17:19 ` Darrick J. Wong
2024-03-13 19:10 ` David Hildenbrand
2024-03-13 21:03 ` David Hildenbrand
2024-03-08 21:34 ` Dave Chinner
2024-03-09 16:19 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 07/24] fsverity: support block-based Merkle tree caching Andrey Albershteyn
2024-03-06 3:56 ` Eric Biggers
2024-03-07 21:54 ` Darrick J. Wong
2024-03-07 22:49 ` Eric Biggers
2024-03-08 3:50 ` Darrick J. Wong
2024-03-09 16:24 ` Darrick J. Wong
2024-03-11 23:22 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 08/24] fsverity: add per-sb workqueue for post read processing Andrey Albershteyn
2024-03-05 1:08 ` Eric Biggers
2024-03-07 21:58 ` Darrick J. Wong
2024-03-07 22:26 ` Eric Biggers
2024-03-08 3:53 ` Darrick J. Wong
2024-03-07 22:55 ` Dave Chinner
2024-03-04 19:10 ` [PATCH v5 09/24] fsverity: add tracepoints Andrey Albershteyn
2024-03-05 0:33 ` Eric Biggers
2024-03-04 19:10 ` [PATCH v5 10/24] iomap: integrate fs-verity verification into iomap's read path Andrey Albershteyn
2024-03-04 23:39 ` Eric Biggers
2024-03-07 22:06 ` Darrick J. Wong
2024-03-07 22:19 ` Eric Biggers
2024-03-07 23:38 ` Dave Chinner
2024-03-07 23:45 ` Darrick J. Wong
2024-03-08 0:47 ` Dave Chinner
2024-03-07 23:59 ` Eric Biggers
2024-03-08 1:20 ` Dave Chinner
2024-03-08 3:16 ` Eric Biggers
2024-03-08 3:57 ` Darrick J. Wong
2024-03-08 3:22 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 11/24] xfs: add XBF_VERITY_SEEN xfs_buf flag Andrey Albershteyn
2024-03-07 22:46 ` Darrick J. Wong
2024-03-08 1:59 ` Dave Chinner
2024-03-08 3:31 ` Darrick J. Wong
2024-03-09 16:28 ` Darrick J. Wong
2024-03-11 0:26 ` Dave Chinner
2024-03-11 15:25 ` Darrick J. Wong
2024-03-12 2:43 ` Eric Biggers
2024-03-12 4:15 ` Darrick J. Wong
2024-03-12 2:45 ` Darrick J. Wong [this message]
2024-03-12 7:01 ` Dave Chinner
2024-03-12 20:04 ` Darrick J. Wong
2024-03-12 21:45 ` Dave Chinner
2024-03-04 19:10 ` [PATCH v5 12/24] xfs: add XFS_DA_OP_BUFFER to make xfs_attr_get() return buffer Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 13/24] xfs: add attribute type for fs-verity Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 14/24] xfs: make xfs_buf_get() to take XBF_* flags Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 15/24] xfs: add XBF_DOUBLE_ALLOC to increase size of the buffer Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 16/24] xfs: add fs-verity ro-compat flag Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 17/24] xfs: add inode on-disk VERITY flag Andrey Albershteyn
2024-03-07 22:06 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 18/24] xfs: initialize fs-verity on file open and cleanup on inode destruction Andrey Albershteyn
2024-03-07 22:09 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 19/24] xfs: don't allow to enable DAX on fs-verity sealsed inode Andrey Albershteyn
2024-03-07 22:09 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 20/24] xfs: disable direct read path for fs-verity files Andrey Albershteyn
2024-03-07 22:11 ` Darrick J. Wong
2024-03-12 12:02 ` Andrey Albershteyn
2024-03-12 16:36 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 21/24] xfs: add fs-verity support Andrey Albershteyn
2024-03-06 4:55 ` Eric Biggers
2024-03-06 5:01 ` Eric Biggers
2024-03-07 23:10 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 22/24] xfs: make scrub aware of verity dinode flag Andrey Albershteyn
2024-03-07 22:18 ` Darrick J. Wong
2024-03-12 12:10 ` Andrey Albershteyn
2024-03-12 16:38 ` Darrick J. Wong
2024-03-13 1:35 ` Darrick J. Wong
2024-03-04 19:10 ` [PATCH v5 23/24] xfs: add fs-verity ioctls Andrey Albershteyn
2024-03-07 22:14 ` Darrick J. Wong
2024-03-12 12:42 ` Andrey Albershteyn
2024-03-04 19:10 ` [PATCH v5 24/24] xfs: enable ro-compat fs-verity flag Andrey Albershteyn
2024-03-07 22:16 ` Darrick J. Wong
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