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From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: Nikolay Borisov <nborisov@suse.com>,
	dsterba@suse.cz, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: Remove impossible condition from mergable_maps
Date: Tue, 8 Jan 2019 15:47:13 +0800	[thread overview]
Message-ID: <88996f56-2740-c3be-1a5c-72a7f40af1f8@gmx.com> (raw)
In-Reply-To: <29983e2d-b525-5b9f-0f37-eb06614cc454@suse.com>



On 2019/1/8 下午3:30, Nikolay Borisov wrote:
> 
> 
> On 7.01.19 г. 21:10 ч., David Sterba wrote:
>> On Tue, Dec 18, 2018 at 03:10:02PM +0200, Nikolay Borisov wrote:
>>> We can never have extents marked as EXTENT_MAP_DELALLOC since this
>>> value is only ever used by btrfs_get_extent_fiemap. In this case the
>>> extent map is created by btrfs_get_extent_fiemap and is never really
>>> published, this flag is used to return the corresponding userspace one.
>>> Considering this, it's pointless having a check for EXTENT_MAP_DELALLOC
>>> in mergable_maps. Just remove it.
>>
>> An assert would be good and a comment at EXTENT_MAP_DELALLOC definition
>> repeating what's in the changelog. Otherwise ok.
> 
> Do we really need the assert though, it's plainly obvious
> EXTENT_MAP_DELALLOC is only set in a single function?

IMHO ASSERT() is not for now, but for the future.
Later on maybe some modification would change when and who sets DELALLOC
bit.
(And that's why there are a lot of seemingly stupid ASSERT(), it won't
hurt anyway).

Thanks,
Qu

> 
>>

  reply	other threads:[~2019-01-08  7:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-18 13:10 [PATCH] btrfs: Remove impossible condition from mergable_maps Nikolay Borisov
2019-01-07 19:10 ` David Sterba
2019-01-08  7:30   ` Nikolay Borisov
2019-01-08  7:47     ` Qu Wenruo [this message]
2019-01-08 14:28       ` David Sterba
2019-01-08 14:53   ` [PATCH v2] " Nikolay Borisov
2019-01-09 14:00     ` David Sterba

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