[RFC PATCH v4 07/11] fs: statx add write zeroes unmap attribute

[Christoph Hellwig]

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?