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From: David Sterba <dsterba@suse.cz>
To: Josef Bacik <josef@toxicpanda.com>
Cc: Qu Wenruo <wqu@suse.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v4 12/18] btrfs: implement try_release_extent_buffer() for subpage metadata support
Date: Sat, 23 Jan 2021 21:36:50 +0100	[thread overview]
Message-ID: <20210123203650.GC1993@twin.jikos.cz> (raw)
In-Reply-To: <4732f7cb-8d1c-6af2-0ec4-9b9cf5a47c3e@toxicpanda.com>

On Wed, Jan 20, 2021 at 10:05:56AM -0500, Josef Bacik wrote:
> On 1/16/21 2:15 AM, Qu Wenruo wrote:
> >   int try_release_extent_buffer(struct page *page)
> >   {
> >   	struct extent_buffer *eb;
> >   
> > +	if (btrfs_sb(page->mapping->host->i_sb)->sectorsize < PAGE_SIZE)
> > +		return try_release_subpage_extent_buffer(page);
> 
> You're using sectorsize again here.  I realize the problem is sectorsize != 
> PAGE_SIZE, but sectorsize != nodesize all the time, so please change all of the 
> patches to check the actual relevant size for the data/metadata type.  Thanks,

We had a long discussion with Qu about that on slack some time ago.
Right now we have sectorsize defining the data block size and also the
metadata unit size and check that as a constraint.

This is not perfect and does not cover all possible page/data/metadata
block size combinations and in the code looks odd, like in
scrub_checksum_tree_block, see the comment.

Adding the subpage support is quite intrusive and we can't cover all
size combinations at the same time so we agreed on first iteration where
sectorsize is still used as the nodesize constraint. This allows to test
the new code and the whole subpage infrastructure on real hw like arm64
or ppc64.

That we'll need to decouple sectorsize from the metadata won't be
forgotten, I've agreed with that conditionally and given how many
patches are floating around it'll become even harder to move forward
with the patches.

  parent reply	other threads:[~2021-01-23 20:41 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-16  7:15 [PATCH v4 00/18] btrfs: add read-only support for subpage sector size Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 01/18] btrfs: update locked page dirty/writeback/error bits in __process_pages_contig() Qu Wenruo
2021-01-19 21:41   ` Josef Bacik
2021-01-21  6:32     ` Qu Wenruo
2021-01-21  6:51       ` Qu Wenruo
2021-01-23 19:13         ` David Sterba
2021-01-24  0:35           ` Qu Wenruo
2021-01-24 11:49             ` David Sterba
2021-01-16  7:15 ` [PATCH v4 02/18] btrfs: merge PAGE_CLEAR_DIRTY and PAGE_SET_WRITEBACK into PAGE_START_WRITEBACK Qu Wenruo
2021-01-19 21:43   ` Josef Bacik
2021-01-19 21:45   ` Josef Bacik
2021-01-16  7:15 ` [PATCH v4 03/18] btrfs: introduce the skeleton of btrfs_subpage structure Qu Wenruo
2021-01-18 22:46   ` David Sterba
2021-01-18 22:54     ` Qu Wenruo
2021-01-19 15:51       ` David Sterba
2021-01-19 16:06         ` David Sterba
2021-01-20  0:19           ` Qu Wenruo
2021-01-23 19:37             ` David Sterba
2021-01-24  0:24               ` Qu Wenruo
2021-01-18 23:01   ` David Sterba
2021-01-16  7:15 ` [PATCH v4 04/18] btrfs: make attach_extent_buffer_page() to handle subpage case Qu Wenruo
2021-01-18 22:51   ` David Sterba
2021-01-19 21:54   ` Josef Bacik
2021-01-19 22:35     ` David Sterba
2021-01-26  7:29       ` Qu Wenruo
2021-01-27 19:58         ` David Sterba
2021-01-20  0:27     ` Qu Wenruo
2021-01-20 14:22       ` Josef Bacik
2021-01-21  1:20         ` Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 05/18] btrfs: make grab_extent_buffer_from_page() " Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 06/18] btrfs: support subpage for extent buffer page release Qu Wenruo
2021-01-20 14:44   ` Josef Bacik
2021-01-21  0:45     ` Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 07/18] btrfs: attach private to dummy extent buffer pages Qu Wenruo
2021-01-20 14:48   ` Josef Bacik
2021-01-21  0:47     ` Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 08/18] btrfs: introduce helper for subpage uptodate status Qu Wenruo
2021-01-19 19:45   ` David Sterba
2021-01-20 14:55   ` Josef Bacik
2021-01-26  7:21     ` Qu Wenruo
2021-01-20 15:00   ` Josef Bacik
2021-01-21  0:49     ` Qu Wenruo
2021-01-21  1:28       ` Josef Bacik
2021-01-21  1:38         ` Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 09/18] btrfs: introduce helper for subpage error status Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 10/18] btrfs: make set/clear_extent_buffer_uptodate() to support subpage size Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 11/18] btrfs: make btrfs_clone_extent_buffer() to be subpage compatible Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 12/18] btrfs: implement try_release_extent_buffer() for subpage metadata support Qu Wenruo
2021-01-20 15:05   ` Josef Bacik
2021-01-21  0:51     ` Qu Wenruo
2021-01-23 20:36     ` David Sterba [this message]
2021-01-25 20:02       ` Josef Bacik
2021-01-16  7:15 ` [PATCH v4 13/18] btrfs: introduce read_extent_buffer_subpage() Qu Wenruo
2021-01-20 15:08   ` Josef Bacik
2021-01-16  7:15 ` [PATCH v4 14/18] btrfs: extent_io: make endio_readpage_update_page_status() to handle subpage case Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 15/18] btrfs: disk-io: introduce subpage metadata validation check Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 16/18] btrfs: introduce btrfs_subpage for data inodes Qu Wenruo
2021-01-19 20:48   ` David Sterba
2021-01-20 15:28   ` Josef Bacik
2021-01-26  7:05     ` Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 17/18] btrfs: integrate page status update for data read path into begin/end_page_read() Qu Wenruo
2021-01-20 15:41   ` Josef Bacik
2021-01-21  1:05     ` Qu Wenruo
2021-01-16  7:15 ` [PATCH v4 18/18] btrfs: allow RO mount of 4K sector size fs on 64K page system Qu Wenruo
2021-01-18 23:17 ` [PATCH v4 00/18] btrfs: add read-only support for subpage sector size David Sterba
2021-01-18 23:26   ` Qu Wenruo
2021-01-24 12:29     ` David Sterba
2021-01-25  1:19       ` Qu Wenruo

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