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[70.77.216.213]) by smtp.gmail.com with ESMTPSA id p185-v6sm2141537itg.34.2018.10.19.22.55.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Oct 2018 22:55:09 -0700 (PDT) From: Andreas Dilger Message-Id: <191D94B6-B91B-45C0-81A2-C6E7A3124731@dilger.ca> Content-Type: multipart/signed; boundary="Apple-Mail=_2AA2161F-DEAC-4A18-B584-431061FB00A9"; protocol="application/pgp-signature"; micalg=pgp-sha256 Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) Subject: Re: [PATCH v2 6/5] statx: add STATX_RESULT_MASK flag Date: Fri, 19 Oct 2018 23:55:04 -0600 In-Reply-To: Cc: David Howells , Miklos Szeredi , Linux FS-devel Mailing List , linux-kernel@vger.kernel.org, Linux API , Michael Kerrisk , Florian Weimer , Amir Goldstein To: Miklos Szeredi References: <20181019143932.6697-1-mszeredi@redhat.com> <18142.1539964788@warthog.procyon.org.uk> X-Mailer: Apple Mail (2.3273) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Apple-Mail=_2AA2161F-DEAC-4A18-B584-431061FB00A9 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii On Oct 19, 2018, at 11:42 AM, Miklos Szeredi wrote: >>> +#define STATX_RESULT_MASK STATX__RESERVED >> >> Please don't use that bit. > > Using it internally is perfectly harmless. If we'll need to extend > statx in the future and make use of this flag externally, then we can > easily move the internal flag somewhere else (e.g. extend request_mask > to 64bit, which we'll probably need to do anyway in that case). I was thinking about this - what is the point of returning an error if STATX__RESERVED is set? If this is used to indicate the presence of e.g. stx_mask2, then newer applications trying to request any of the flags encoded into stx_mask2 will get an error, rather than the expected behaviour of "ignore flags you don't understand, and don't set them in the return stx_mask". Essentially, this will make STATX__RESERVED useless in the future, since no application will be able to use it without getting an error if they are running on an old kernel. Cheers, Andreas --Apple-Mail=_2AA2161F-DEAC-4A18-B584-431061FB00A9 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iQIzBAEBCAAdFiEEDb73u6ZejP5ZMprvcqXauRfMH+AFAlvKwzgACgkQcqXauRfM H+ATqxAApNR2xdaiSRfe2Fgfo8reQlhc30NE6O1bmlWMKVdMR5/QZoJ33qvSD3YM T01+drMlFx+L5Onoy9VF36bcvMm7LO3AN6ghINgQXVyPyitFXJiNn8DU/wwIwzNR 8evyURtDSgdw0+BNOx6zuuLcOsDcAhSS9HwCpf57upQWVsnKsqTs0ZOPQMM2Bz3f /FcuVbe8UMyvyORUg+3AS+aX05MG12LXRClCGMyVnczbbfABtW+PJMtyZUvniqJd AmXS0y41IV0PU7Fun5m0J2EEdtQvMkqcT3ULutB5VtcZGAitBuBIKBeQs7a5PBlK lk0koGse1IR4sZi3NrCg+8UAUAQJG7Zvt6N4QFEN6pvilK3SflOydGEI7IQ7fQgJ 52xCWLSOXwQvm1/oOFOC3sTOmZHOEwVn+YeEpWIaNHb9xSMuNgdBDYnpsVoMDdec w/2HECiWqi5+SkwRFzRjaeLkAHs5pnjVrDsV4i17gn4eJSIrg1wt0vDUbbPFBUJI qgqenVwOdUkrmiJ2PGnKzUoh0/WIhy3jHVhs9TTFLeSFMORP0KOmzVDuLX9TrY7u TTWKEj4bxU2NhAZCt2YmPcb+DZnpo/9hGziL1CF3zHqBgc9x/86si6lLnghZ40uA r+s3TJzEj02WHO3DIHk4Fr4YrjGyPI5Ys+MyhLwObu7JSDhQrRw= =X1q8 -----END PGP SIGNATURE----- --Apple-Mail=_2AA2161F-DEAC-4A18-B584-431061FB00A9--