From: Christoph Hellwig <hch@infradead.org>
To: Chao Yu <chao@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
Zorro Lang <zlang@kernel.org>,
Jan Prusakowski <jprusakowski@google.com>,
linux-f2fs-devel@lists.sourceforge.net, fstests@vger.kernel.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?
prev parent reply other threads:[~2026-07-20 8:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-22 7:04 [PATCH] generic/064: allow 50 extents on F2FS after fcollapse Jan Prusakowski
2026-06-23 8:46 ` [f2fs-dev] " Chao Yu
2026-06-24 7:46 ` Christoph Hellwig
2026-06-29 16:37 ` Zorro Lang
2026-06-30 12:09 ` [f2fs-dev] " Chao Yu
2026-07-19 9:24 ` Zorro Lang
2026-07-20 8:04 ` Christoph Hellwig [this message]
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