From: John Garry <john.g.garry@oracle.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Christoph Hellwig <hch@lst.de>,
axboe@kernel.dk, kbusch@kernel.org, sagi@grimberg.me,
jejb@linux.ibm.com, martin.petersen@oracle.com,
djwong@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org,
chandan.babu@oracle.com, dchinner@redhat.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, jbongio@google.com,
linux-api@vger.kernel.org
Subject: Re: [PATCH 17/21] fs: xfs: iomap atomic write support
Date: Tue, 5 Dec 2023 11:09:46 +0000 [thread overview]
Message-ID: <4b41c8df-bc56-4ff1-b2ed-70ec00080f95@oracle.com> (raw)
In-Reply-To: <20231205045539.GH509422@mit.edu>
On 05/12/2023 04:55, Theodore Ts'o wrote:
>> AFAICS, this is without any kernel changes, so no guarantee of unwanted
>> splitting or merging of bios.
> Well, more than one company has audited the kernel paths, and it turns
> out that for selected Kernel versions, after doing desk-check
> verification of the relevant kernel baths, as well as experimental
> verification via testing to try to find torn writes in the kernel, we
> can make it safe for specific kernel versions which might be used in
> hosted MySQL instances where we control the kernel, the mysql server,
> and the emulated block device (and we know the database is doing
> Direct I/O writes --- this won't work for PostgreSQL). I gave a talk
> about this at Google I/O Next '18, five years ago[1].
>
> [1]https://urldefense.com/v3/__https://www.youtube.com/watch?v=gIeuiGg-_iw__;!!ACWV5N9M2RV99hQ!I4iRp4xUyzAT0UwuEcnUBBCPKLXFKfk5FNmysFbKcQYfl0marAll5xEEVyB5mMFDqeckCWLmjU1aCR2Z$
>
> Given the performance gains (see the talk (see the comparison of the
> at time 19:31 and at 29:57) --- it's quite compelling.
>
> Of course, I wouldn't recommend this approach for a naive sysadmin,
> since most database adminsitrators won't know how to audit kernel code
> (see the discussion at time 35:10 of the video), and reverify the
> entire software stack before every kernel upgrade.
Sure
> The challenge is
> how to do this safely.
Right, and that is why I would be concerned about advertising torn-write
protection support, but someone has not gone through the effort of
auditing and verification phase to ensure that this does not happen in
their software stack ever.
>
> The fact remains that both Amazon's EBS and Google's Persistent Disk
> products are implemented in such a way that writes will not be torn
> below the virtual machine, and the guarantees are in fact quite a bit
> stronger than what we will probably end up advertising via NVMe and/or
> SCSI. It wouldn't surprise me if this is the case (or could be made
> to be the case) For Oracle Cloud as well.
>
> The question is how to make this guarantee so that the kernel knows
> when various cloud-provided block devicse do provide these greater
> guarantees, and then how to make it be an architected feature, as
> opposed to a happy implementation detail that has to be verified at
> every kernel upgrade.
The kernel can only judge atomic write support from what the HW product
data tells us, so cloud-provided block devices need to provide that
information as best possible if emulating the some storage technology.
Thanks,
John
next prev parent reply other threads:[~2023-12-05 11:10 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-29 10:27 [PATCH 00/21] block atomic writes John Garry
2023-09-29 10:27 ` [PATCH 01/21] block: Add atomic write operations to request_queue limits John Garry
2023-10-03 16:40 ` Bart Van Assche
2023-10-04 3:00 ` Martin K. Petersen
2023-10-04 17:28 ` Bart Van Assche
2023-10-04 18:26 ` Martin K. Petersen
2023-10-04 21:00 ` Bart Van Assche
2023-10-05 8:22 ` John Garry
2023-11-09 15:10 ` Christoph Hellwig
2023-11-09 17:01 ` John Garry
2023-11-10 6:23 ` Christoph Hellwig
2023-11-10 9:04 ` John Garry
2023-09-29 10:27 ` [PATCH 02/21] block: Limit atomic writes according to bio and queue limits John Garry
2023-11-09 15:13 ` Christoph Hellwig
2023-11-09 17:41 ` John Garry
2023-12-04 3:19 ` Ming Lei
2023-12-04 3:55 ` Ming Lei
2023-12-04 9:35 ` John Garry
2023-09-29 10:27 ` [PATCH 03/21] fs/bdev: Add atomic write support info to statx John Garry
2023-09-29 22:49 ` Eric Biggers
2023-10-01 13:23 ` Bart Van Assche
2023-10-02 9:51 ` John Garry
2023-10-02 18:39 ` Bart Van Assche
2023-10-03 0:28 ` Martin K. Petersen
2023-11-09 15:15 ` Christoph Hellwig
2023-10-03 1:51 ` Dave Chinner
2023-10-03 2:57 ` Darrick J. Wong
2023-10-03 7:23 ` John Garry
2023-10-03 15:46 ` Darrick J. Wong
2023-10-04 14:19 ` John Garry
2023-09-29 10:27 ` [PATCH 04/21] fs: Add RWF_ATOMIC and IOCB_ATOMIC flags for atomic write support John Garry
2023-10-06 18:15 ` Jeremy Bongio
2023-10-09 22:02 ` Dave Chinner
2023-09-29 10:27 ` [PATCH 05/21] block: Add REQ_ATOMIC flag John Garry
2023-09-29 10:27 ` [PATCH 06/21] block: Pass blk_queue_get_max_sectors() a request pointer John Garry
2023-09-29 10:27 ` [PATCH 07/21] block: Limit atomic write IO size according to atomic_write_max_sectors John Garry
2023-09-29 10:27 ` [PATCH 08/21] block: Error an attempt to split an atomic write bio John Garry
2023-09-29 10:27 ` [PATCH 09/21] block: Add checks to merging of atomic writes John Garry
2023-09-30 13:40 ` kernel test robot
2023-10-02 22:50 ` Nathan Chancellor
2023-10-04 11:40 ` John Garry
2023-09-29 10:27 ` [PATCH 10/21] block: Add fops atomic write support John Garry
2023-09-29 17:51 ` Bart Van Assche
2023-10-02 10:10 ` John Garry
2023-10-02 19:12 ` Bart Van Assche
2023-10-03 0:48 ` Martin K. Petersen
2023-10-03 16:55 ` Bart Van Assche
2023-10-04 2:53 ` Martin K. Petersen
2023-10-04 17:22 ` Bart Van Assche
2023-10-04 18:17 ` Martin K. Petersen
2023-10-05 17:10 ` Bart Van Assche
2023-10-05 22:36 ` Dave Chinner
2023-10-05 22:58 ` Bart Van Assche
2023-10-06 4:31 ` Dave Chinner
2023-10-06 17:22 ` Bart Van Assche
2023-10-07 1:21 ` Martin K. Petersen
2023-10-03 8:37 ` John Garry
2023-10-03 16:45 ` Bart Van Assche
2023-10-04 9:14 ` John Garry
2023-10-04 17:34 ` Bart Van Assche
2023-10-04 21:59 ` Dave Chinner
2023-12-04 2:30 ` Ming Lei
2023-12-04 9:27 ` John Garry
2023-12-04 12:18 ` Ming Lei
2023-12-04 13:13 ` John Garry
2023-12-05 1:45 ` Ming Lei
2023-12-05 10:49 ` John Garry
2023-09-29 10:27 ` [PATCH 11/21] fs: xfs: Don't use low-space allocator for alignment > 1 John Garry
2023-10-03 1:16 ` Dave Chinner
2023-10-03 3:00 ` Darrick J. Wong
2023-10-03 4:34 ` Dave Chinner
2023-10-03 10:22 ` John Garry
2023-09-29 10:27 ` [PATCH 12/21] fs: xfs: Introduce FORCEALIGN inode flag John Garry
2023-11-09 15:24 ` Christoph Hellwig
2023-09-29 10:27 ` [PATCH 13/21] fs: xfs: Make file data allocations observe the 'forcealign' flag John Garry
2023-10-03 1:42 ` Dave Chinner
2023-10-03 10:13 ` John Garry
2023-09-29 10:27 ` [PATCH 14/21] fs: xfs: Enable file data forcealign feature John Garry
2023-09-29 10:27 ` [PATCH 15/21] fs: xfs: Support atomic write for statx John Garry
2023-10-03 3:32 ` Dave Chinner
2023-10-03 10:56 ` John Garry
2023-10-03 16:10 ` Darrick J. Wong
2023-09-29 10:27 ` [PATCH 16/21] fs: iomap: Atomic write support John Garry
2023-10-03 4:24 ` Dave Chinner
2023-10-03 12:55 ` John Garry
2023-10-03 16:47 ` Darrick J. Wong
2023-10-04 1:16 ` Dave Chinner
2023-10-24 12:59 ` John Garry
2023-09-29 10:27 ` [PATCH 17/21] fs: xfs: iomap atomic " John Garry
2023-11-09 15:26 ` Christoph Hellwig
2023-11-10 10:42 ` John Garry
2023-11-28 8:56 ` John Garry
2023-11-28 13:56 ` Christoph Hellwig
2023-11-28 17:42 ` John Garry
2023-11-29 2:45 ` Martin K. Petersen
2023-12-04 13:45 ` Christoph Hellwig
2023-12-04 15:19 ` John Garry
2023-12-04 15:39 ` Christoph Hellwig
2023-12-04 18:06 ` John Garry
2023-12-05 4:55 ` Theodore Ts'o
2023-12-05 11:09 ` John Garry [this message]
2023-12-05 13:59 ` Ming Lei
2023-09-29 10:27 ` [PATCH 18/21] scsi: sd: Support reading atomic properties from block limits VPD John Garry
2023-09-29 17:54 ` Bart Van Assche
2023-10-02 11:27 ` John Garry
2023-10-06 17:52 ` Bart Van Assche
2023-10-06 23:48 ` Martin K. Petersen
2023-09-29 10:27 ` [PATCH 19/21] scsi: sd: Add WRITE_ATOMIC_16 support John Garry
2023-09-29 17:59 ` Bart Van Assche
2023-10-02 11:36 ` John Garry
2023-10-02 19:21 ` Bart Van Assche
2023-09-29 10:27 ` [PATCH 20/21] scsi: scsi_debug: Atomic write support John Garry
2023-09-29 10:27 ` [PATCH 21/21] nvme: Support atomic writes John Garry
[not found] ` <CGME20231004113943eucas1p23a51ce5ef06c36459f826101bb7b85fc@eucas1p2.samsung.com>
2023-10-04 11:39 ` Pankaj Raghav
2023-10-05 10:24 ` John Garry
2023-10-05 13:32 ` Pankaj Raghav
2023-10-05 15:05 ` John Garry
2023-11-09 15:36 ` Christoph Hellwig
2023-11-09 15:42 ` Matthew Wilcox
2023-11-09 15:46 ` Christoph Hellwig
2023-11-09 19:08 ` John Garry
2023-11-10 6:29 ` Christoph Hellwig
2023-11-10 8:44 ` John Garry
2023-09-29 14:58 ` [PATCH 00/21] block " Bart Van Assche
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4b41c8df-bc56-4ff1-b2ed-70ec00080f95@oracle.com \
--to=john.g.garry@oracle.com \
--cc=axboe@kernel.dk \
--cc=brauner@kernel.org \
--cc=chandan.babu@oracle.com \
--cc=dchinner@redhat.com \
--cc=djwong@kernel.org \
--cc=hch@lst.de \
--cc=jbongio@google.com \
--cc=jejb@linux.ibm.com \
--cc=kbusch@kernel.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=linux-xfs@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=sagi@grimberg.me \
--cc=tytso@mit.edu \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).