From: "hch@infradead.org" <hch@infradead.org>
To: Qu Wenruo <wqu@suse.com>
Cc: "hch@infradead.org" <hch@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
Kanchan Joshi <joshi.k@samsung.com>,
Theodore Ts'o <tytso@mit.edu>,
"lsf-pc@lists.linux-foundation.org"
<lsf-pc@lists.linux-foundation.org>,
"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"josef@toxicpanda.com" <josef@toxicpanda.com>
Subject: Re: [LSF/MM/BPF TOPIC] File system checksum offload
Date: Mon, 3 Feb 2025 00:40:22 -0800 [thread overview]
Message-ID: <Z6CA9sDUZ_nDj5LD@infradead.org> (raw)
In-Reply-To: <efcb712d-15f9-49ab-806d-a924a614034f@suse.com>
On Mon, Feb 03, 2025 at 07:06:15PM +1030, Qu Wenruo wrote:
> Thus my current plan to fix it is to make btrfs to skip csum for direct IO.
> This will make btrfs to align with EXT4/XFS behavior, without the complex
> AS_STABLE_FLAGS passing (and there is no way for user space to probe that
> flag IIRC).
>
> But that will break the current per-inode level NODATASUM setting, and will
> cause some incompatibility (a new incompat flag needed, extra handling if no
> data csum found, extra fsck support etc).
I don't think simply removing the checksums when using direct I/O is
a good idea as it unexpectedly reduces the protection envelope. The
best (or least bad) fix would be to simply not support actually direct
I/O without NODATASUM and fall back to buffered I/O (preferably the new
uncached variant from Jens) unless explicitly overridden.
next prev parent reply other threads:[~2025-02-03 8:40 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20250130092400epcas5p1a3a9d899583e9502ed45fe500ae8a824@epcas5p1.samsung.com>
2025-01-30 9:15 ` [LSF/MM/BPF TOPIC] File system checksum offload Kanchan Joshi
2025-01-30 14:28 ` Theodore Ts'o
2025-01-30 20:39 ` [Lsf-pc] " Martin K. Petersen
2025-01-31 4:40 ` Theodore Ts'o
2025-01-31 7:07 ` Christoph Hellwig
2025-01-31 13:11 ` Kanchan Joshi
2025-02-03 7:47 ` Johannes Thumshirn
2025-02-03 7:56 ` Christoph Hellwig
2025-02-03 8:04 ` Johannes Thumshirn
2025-02-03 8:06 ` hch
2025-02-03 8:16 ` Qu Wenruo
2025-02-03 8:26 ` Matthew Wilcox
2025-02-03 8:30 ` hch
2025-02-03 8:36 ` Qu Wenruo
2025-02-03 8:40 ` hch [this message]
2025-02-03 8:51 ` Qu Wenruo
2025-02-03 8:57 ` hch
2025-02-03 8:26 ` hch
2025-02-03 13:27 ` Kanchan Joshi
2025-02-03 23:17 ` Qu Wenruo
2025-02-04 5:48 ` hch
2025-02-04 5:16 ` hch
2025-03-18 7:06 ` Kanchan Joshi
2025-03-18 8:07 ` hch
2025-03-19 18:06 ` Kanchan Joshi
2025-03-20 5:48 ` hch
2025-02-03 13:32 ` Kanchan Joshi
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