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From: Christoph Hellwig <hch@lst.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	Kent Overstreet <kent.overstreet@linux.dev>,
	Hongbo Li <lihongbo22@huawei.com>,
	linux-bcachefs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-block@vger.kernel.org, hch@lst.de
Subject: Re: bvec_iter.bi_sector -> loff_t?
Date: Thu, 20 Jun 2024 17:20:26 +0200	[thread overview]
Message-ID: <20240620152026.GA25908@lst.de> (raw)
In-Reply-To: <ZnRHi3Cfh_w7ZQa1@casper.infradead.org>

On Thu, Jun 20, 2024 at 04:15:23PM +0100, Matthew Wilcox wrote:
> > 
> > and have O_DIRECT with a 32-bit memory alignment work just fine, where
> > before it would EINVAL. The sector size memory alignment thing has
> > always been odd and never rooted in anything other than "oh let's just
> > require the whole combination of size/disk offset/alignment to be sector
> > based".
> 
> Oh, cool!  https://man7.org/linux/man-pages/man2/open.2.html
> doesn't know about this yet; is anyone working on updating it?

Just remember that there are two kinds of alignments:

 - the memory alignment, which Jens is talking about
 - the offset/size alignment, which is set by the LBA size

statx (optionally) exposes both in the stx_dio_mem_align and
stx_dio_offset_align fields, which are documented in the statx(2)
man page.  For network file systems like nfs there might be no
alignment requirements at all.

  parent reply	other threads:[~2024-06-20 15:20 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20240620132157.888559-1-lihongbo22@huawei.com>
2024-06-20 13:36 ` bvec_iter.bi_sector -> loff_t? (was: Re: [PATCH] bcachefs: allow direct io fallback to buffer io for) unaligned length or offset Kent Overstreet
2024-06-20 13:54   ` Matthew Wilcox
2024-06-20 14:16     ` Kent Overstreet
2024-06-20 14:49       ` Matthew Wilcox
2024-06-20 14:56         ` bvec_iter.bi_sector -> loff_t? Jens Axboe
2024-06-20 15:15           ` Matthew Wilcox
2024-06-20 15:18             ` Jens Axboe
2024-06-20 16:26               ` Keith Busch
2024-06-20 15:20             ` Christoph Hellwig [this message]
2024-06-20 15:21               ` Jens Axboe
2024-06-21  2:37           ` Hongbo Li
2024-06-21  3:05             ` Kent Overstreet
2024-06-20 15:35         ` bvec_iter.bi_sector -> loff_t? (was: Re: [PATCH] bcachefs: allow direct io fallback to buffer io for) unaligned length or offset Kent Overstreet
2024-06-21  3:13         ` bvec_iter.bi_sector -> loff_t? Hongbo Li
2024-06-20 15:30     ` bvec_iter.bi_sector -> loff_t? (was: Re: [PATCH] bcachefs: allow direct io fallback to buffer io for) unaligned length or offset Christoph Hellwig
2024-06-20 15:43       ` Kent Overstreet
2024-06-21  1:48         ` Ming Lei
2024-06-21  3:07           ` Kent Overstreet
2024-06-21  3:36             ` Ming Lei
2024-06-21  3:52               ` Kent Overstreet

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