From: Christoph Hellwig <hch@lst.de>
To: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Christoph Hellwig <hch@lst.de>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
darrick.wong@oracle.com, david@fromorbit.com
Subject: Re: [PATCH 3/6] iomap: Check iblocksize before transforming page->private
Date: Wed, 26 Jun 2019 08:16:58 +0200 [thread overview]
Message-ID: <20190626061658.GA23972@lst.de> (raw)
In-Reply-To: <20190625185659.tqaikm27onz6g3jt@fiona>
On Tue, Jun 25, 2019 at 01:56:59PM -0500, Goldwyn Rodrigues wrote:
> Btrfs uses page->private to identify which extent_buffer it belongs to.
> So, if you read, it fills the page->private. Then you try to write to
> it, iomap will assume it to be iomap_page pointer.
Yes, and that is going to run into problems sooner or later, that is
if you want to support sub-page size block sizes in btrfs, which I
though is work in progress, or if you ever want to write through iomap.
> I don't think we can move extent_buffer out of page->private for btrfs.
> Any other ideas?
I think you'll have to. That being said I don't see why you'd need
data in page->private for pages potentially being read in a setup
where blocksize == PAGESIZE anyway.
next prev parent reply other threads:[~2019-06-26 6:17 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-21 19:28 [PATCH 0/6] Btrfs iomap Goldwyn Rodrigues
2019-06-21 19:28 ` [PATCH 1/6] iomap: Use a IOMAP_COW/srcmap for a read-modify-write I/O Goldwyn Rodrigues
2019-06-22 0:46 ` Darrick J. Wong
2019-06-25 19:17 ` Goldwyn Rodrigues
2019-06-26 6:21 ` Christoph Hellwig
2019-06-24 7:07 ` Christoph Hellwig
2019-06-25 19:14 ` Goldwyn Rodrigues
2019-06-26 1:36 ` Shiyang Ruan
2019-06-26 6:39 ` Christoph Hellwig
2019-06-26 16:10 ` Goldwyn Rodrigues
2019-06-26 17:34 ` Darrick J. Wong
2019-06-26 18:00 ` Darrick J. Wong
2019-06-26 18:42 ` Goldwyn Rodrigues
2019-06-21 19:28 ` [PATCH 2/6] iomap: Read page from srcmap for IOMAP_COW Goldwyn Rodrigues
2019-06-22 0:41 ` Darrick J. Wong
2019-06-21 19:28 ` [PATCH 3/6] iomap: Check iblocksize before transforming page->private Goldwyn Rodrigues
2019-06-22 0:21 ` Darrick J. Wong
2019-06-25 19:22 ` Goldwyn Rodrigues
2019-06-24 7:05 ` Christoph Hellwig
2019-06-25 18:56 ` Goldwyn Rodrigues
2019-06-25 20:04 ` Filipe Manana
2019-06-26 3:03 ` Goldwyn Rodrigues
2019-06-26 6:42 ` Nikolay Borisov
2019-06-26 6:16 ` Christoph Hellwig [this message]
2019-06-21 19:28 ` [PATCH 4/6] btrfs: Add a simple buffered iomap write Goldwyn Rodrigues
2019-06-21 19:28 ` [PATCH 5/6] btrfs: Add CoW in iomap based writes Goldwyn Rodrigues
2019-06-21 19:28 ` [PATCH 6/6] btrfs: remove buffered write code made unnecessary Goldwyn Rodrigues
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=20190626061658.GA23972@lst.de \
--to=hch@lst.de \
--cc=darrick.wong@oracle.com \
--cc=david@fromorbit.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=rgoldwyn@suse.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.