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From: Daeho Jeong <daeho43@gmail.com>
To: Chao Yu <chao@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
	Daeho Jeong <daehojeong@google.com>
Subject: Re: [f2fs-dev] [PATCH v4] f2fs: introduce fragment allocation mode mount option
Date: Fri, 3 Sep 2021 21:40:13 -0700	[thread overview]
Message-ID: <CACOAw_yBYZzUVGV-A7K57zqrcAaZv7nFSk9mSj9AC6jTTeU7Vw@mail.gmail.com> (raw)
In-Reply-To: <8f8e4695-4062-60c4-0f91-2a1f6a5b0a11@kernel.org>

> As a per curseg field.
>
> > Maybe, we run into the same race condition issue you told before for
> > fragment_remained_chunk.
> > Could you clarify this more?
>
> e.g.
>
> F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_FIXED_BLK
> fragment_chunk_size = 384
> fragment_hole_size = 384
>
> When creating hole:
>
> - f2fs_allocate_data_block
>   - __refresh_next_blkoff
>     chunk locates in [0, 383] of current segment
>     seg->next_blkoff = 384
>     sbi->fragment_remained_chunk = 0
>     then we will reset sbi->fragment_remained_chunk to 384
>     and move seg->next_blkoff forward to 768 (384 + 384)
>   - __has_curseg_space() returns false
>   - allocate_segment() allocates new current segment
>
> So, for such case that hole may cross two segments, hole size may be truncated
> to left size of previous segment.

First, sbi->fragment_remained_chunk should be seg->fragment_remained_chunk.
I understand what you mean, so you mean we need to take the leftover
"hole" size over to the next segment?
In the example, the leftover hole size will be (384 - (512-384)). Do
you want to take this over to the next segment?

  reply	other threads:[~2021-09-04  4:40 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-02 17:24 Daeho Jeong
2021-09-02 23:57 ` [f2fs-dev] " Chao Yu
2021-09-03 20:33   ` Daeho Jeong
2021-09-04  3:33     ` Chao Yu
2021-09-04  4:40       ` Daeho Jeong [this message]
2021-09-04  6:45         ` Chao Yu
2021-09-07 18:12           ` Daeho Jeong
2021-09-09 23:50             ` Chao Yu
2021-09-10 14:34               ` Daeho Jeong
2021-09-10 15:24                 ` Daeho Jeong
2021-09-11 10:42                   ` Chao Yu
2021-09-10 23:13 ` Jaegeuk Kim
2021-09-11 23:45   ` [f2fs-dev] " Chao Yu
2021-09-20 22:57     ` Jaegeuk Kim
2021-09-22 15:23       ` Chao Yu

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