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From: Qu Wenruo <wqu@suse.com>
To: Nikolay Borisov <nborisov@suse.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v2 2/3] btrfs: file-item: remove the btrfs_find_ordered_sum() call in btrfs_lookup_bio_sums()
Date: Thu, 29 Oct 2020 15:53:57 +0800	[thread overview]
Message-ID: <13937055-ab09-0a0f-b1e4-bfe7a710f5b1@suse.com> (raw)
In-Reply-To: <12990e1a-6e59-b0e3-5d26-34c80e31b601@suse.com>



On 2020/10/29 下午3:47, Nikolay Borisov wrote:
> 
> 
> On 29.10.20 г. 9:12 ч., Qu Wenruo wrote:
>> The function btrfs_lookup_bio_sums() is only called for read bios.
>> While btrfs_find_ordered_sum() is to search ordered extent sums, which
> 
> 
> And what if we issue a read for a region which still has in-flight
> ordered sums?
> 
Then how could the page tagged with WRITEBACK need we to do the read?

At buffered time, we have already dirtied the page, means if we do read,
we will get it from page cache directly, no need to trigger read.

Thanks,
Qu


  reply	other threads:[~2020-10-29  7:56 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29  7:12 [PATCH v2 0/3] btrfs: btrfs_lookup_bio_sums() related fixes Qu Wenruo
2020-10-29  7:12 ` [PATCH v2 1/3] btrfs: file-item: use nodesize to determine whether we need readhead for btrfs_lookup_bio_sums() Qu Wenruo
2020-10-29 18:57   ` Josef Bacik
2020-10-29 23:57     ` Qu Wenruo
2020-10-29  7:12 ` [PATCH v2 2/3] btrfs: file-item: remove the btrfs_find_ordered_sum() call in btrfs_lookup_bio_sums() Qu Wenruo
2020-10-29  7:47   ` Nikolay Borisov
2020-10-29  7:53     ` Qu Wenruo [this message]
2020-10-29 18:51   ` Josef Bacik
2020-10-29  7:12 ` [PATCH v2 3/3] btrfs: file-item: refactor btrfs_lookup_bio_sums() to handle out-of-order bvecs Qu Wenruo
2020-10-29 11:50   ` Nikolay Borisov
2020-10-29 12:43     ` Qu Wenruo
2020-10-29 13:54       ` David Sterba
2020-10-29 14:11         ` Qu Wenruo

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