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Date: Tue, 6 May 2025 07:02:39 +0200
From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Zhang Yi <yi.zhang@huaweicloud.com>,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
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	brauner@kernel.org, yi.zhang@huawei.com, chengzhihao1@huawei.com,
	yukuai3@huawei.com, yangerkun@huawei.com
Subject: Re: [RFC PATCH v4 07/11] fs: statx add write zeroes unmap attribute
Message-ID: <20250506050239.GA27687@lst.de>
References: <20250421021509.2366003-1-yi.zhang@huaweicloud.com> <20250421021509.2366003-8-yi.zhang@huaweicloud.com> <20250505132208.GA22182@lst.de> <20250505142945.GJ1035866@frogsfrogsfrogs>
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On Mon, May 05, 2025 at 07:29:45AM -0700, Darrick J. Wong wrote:
> attributes_mask contains attribute flags known to the filesystem,
> whereas attributes contains flags actually set on the file.
> "known_attributes" would have been a better name, but that's water under
> the bridge. :P

Oooh.  I think I was very confused at what this patch does, and what
it does seems confused as well.

The patch adds a new flag to the STATX_ATTR_* namespace, which
historically was used for persistent on-disk flags like immutable,
not the STATX_* namespace where I assumed it, and which has no
support mask.  Which seems really odd for a pure kernel feature.
Then again it seems to follow STATX_ATTR_WRITE_ATOMIC which seems
just as wrongly place unless I'm missing something?