From: Christoph Hellwig <hch@infradead.org>
To: Chao Yu <chao@kernel.org>
Cc: Zorro Lang <zlang@kernel.org>,
fstests@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net,
Christoph Hellwig <hch@infradead.org>,
jaegeuk@kernel.org
Subject: Re: [f2fs-dev] [PATCH] generic/064: allow 50 extents on F2FS after fcollapse
Date: Mon, 20 Jul 2026 01:04:03 -0700 [thread overview]
Message-ID: <al3Wcz5pIujPdTrL@infradead.org> (raw)
In-Reply-To: <e7a57c5e-62de-401d-8e39-f7409f398a84@kernel.org>
On Tue, Jun 30, 2026 at 08:09:19PM +0800, Chao Yu wrote:
>
> Let me explain it briefly, this is because f2fs has only one copy of reverse
> mapping table (aka SSA), for any checkpointed data, we can not modify SSA info
> directly during remap, otherwise, after sudden power-cut, we will suffer
> inconsistent issue in between reverse mapping table and mapping table. So, f2fs
> choose to rewrite for any checkpointed data.
So looking at this explanation and the code, f2fs does not actually
support COLLAPSE_RANGE at all, but emulates by doing a full data
copy. What is the point of this and lying to the user that it supports
and operation that isn't actually supported as the intended metadata
only swizzle?
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next prev parent reply other threads:[~2026-07-20 8:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-22 7:04 [f2fs-dev] [PATCH] generic/064: allow 50 extents on F2FS after fcollapse Jan Prusakowski via Linux-f2fs-devel
2026-06-23 8:46 ` Chao Yu via Linux-f2fs-devel
2026-06-24 7:46 ` Christoph Hellwig
2026-06-29 16:37 ` Zorro Lang via Linux-f2fs-devel
2026-06-30 12:09 ` Chao Yu via Linux-f2fs-devel
2026-07-19 9:24 ` Zorro Lang via Linux-f2fs-devel
2026-07-22 1:22 ` Chao Yu via Linux-f2fs-devel
2026-07-20 8:04 ` Christoph Hellwig [this message]
2026-07-22 1:12 ` Chao Yu via Linux-f2fs-devel
2026-07-22 8:59 ` Christoph Hellwig
2026-07-22 12:32 ` Chao Yu via Linux-f2fs-devel
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