From: Jens Axboe <axboe@kernel.dk>
To: Tal Zussman <tz2294@columbia.edu>,
"Tigran A. Aivazian" <aivazian.tigran@gmail.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Namjae Jeon <linkinjeon@kernel.org>,
Sungjong Seo <sj1557.seo@samsung.com>,
Yuezhang Mo <yuezhang.mo@sony.com>,
Dave Kleikamp <shaggy@kernel.org>,
Ryusuke Konishi <konishi.ryusuke@gmail.com>,
Viacheslav Dubeyko <slava@dubeyko.com>,
Konstantin Komarov <almaz.alexandrovich@paragon-software.com>,
Bob Copeland <me@bobcopeland.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
jfs-discussion@lists.sourceforge.net,
linux-nilfs@vger.kernel.org, ntfs3@lists.linux.dev,
linux-karma-devel@lists.sourceforge.net
Subject: Re: [PATCH RFC] block: enable RWF_DONTCACHE for block devices
Date: Thu, 19 Feb 2026 08:24:38 -0700 [thread overview]
Message-ID: <35866783-2312-4e31-904d-3746510eaf56@kernel.dk> (raw)
In-Reply-To: <20260218-blk-dontcache-v1-1-fad6675ef71f@columbia.edu>
On 2/18/26 2:13 PM, Tal Zussman wrote:
> Block device buffered reads and writes already pass through
> filemap_read() and iomap_file_buffered_write() respectively, both of
> which handle IOCB_DONTCACHE. Enable RWF_DONTCACHE for block device files
> by setting FOP_DONTCACHE in def_blk_fops.
>
> For CONFIG_BUFFER_HEAD paths, thread the kiocb through
> block_write_begin() so that buffer_head-based I/O can use DONTCACHE
> behavior as well. Callers without a kiocb context (e.g. nilfs2 recovery)
> pass NULL, which preserves the existing behavior.
>
> This support is useful for databases that operate on raw block devices,
> among other userspace applications.
OOO right now so I'll take a real look when I'm back, but when I
originally did this work, it's not the issue side that's the issue. It's
the pruning done from completion context, and you need to ensure that's
sane context for that (non-irq).
--
Jens Axboe
next prev parent reply other threads:[~2026-02-19 15:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-18 21:13 [PATCH RFC] block: enable RWF_DONTCACHE for block devices Tal Zussman
2026-02-19 12:03 ` Jan Kara
2026-02-19 15:24 ` Jens Axboe [this message]
2026-02-25 22:42 ` Tal Zussman
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