Date: Sat, 09 Mar 2024 14:07:10 +0100 From: Alexander Leidinger <Alexander@Leidinger.net> To: Warner Losh <imp@bsdimp.com> Cc: Jamie Landeg-Jones <jamie@catflap.org>, current@freebsd.org Subject: Re: Reason why "nocache" option is not displayed in "mount"? Message-ID: <b8a9464bc6e371568579c316e1e48101@Leidinger.net> In-Reply-To: <CANCZdfq2Z30jgh6Wt9Set=fZ271qr42Thy73YOxF=bh04R6Bfg@mail.gmail.com> References: <09bb45dea82d96c11f34cc48dda540dc@Leidinger.net> <202403072005.427K58KX014923@donotpassgo.dyslexicfish.net> <CANCZdfq2Z30jgh6Wt9Set=fZ271qr42Thy73YOxF=bh04R6Bfg@mail.gmail.com>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --=_2fa80b1d684482adebd320c12be819ec Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8; format=flowed Am 2024-03-09 06:07, schrieb Warner Losh: > On Thu, Mar 7, 2024 at 1:05 PM Jamie Landeg-Jones <jamie@catflap.org> > wrote: > >> Alexander Leidinger <Alexander@Leidinger.net> wrote: >> >>> Hi, >>> >>> what is the reason why "nocache" is not displayed in the output of >>> "mount" for nullfs options? >> >> Good catch. I also notice that "hidden" is not shown either. >> >> I guess that as for some time, "nocache" was a "secret" option, no-one >> update "mount" to display it? > > So a couple of things to know. > > First, there's a list of known options. These are converted to a > bitmask. This is then decoded and reported by mount. The other strings > are passed to the filesystem directly. They decode it and do things, > but they don't export them (that I can find). I believe that's why they > aren't reported with 'mount'. There's a couple of other options in > /etc/fstab that are pseudo options too. That's the technical explanation why it doesn't work. I'm a step further since initial mail, I even had a look at the code and know that nocache is recorded in a nullfs private flag and that the userland can not access this (mount looks at struct statfs which doesn't provide info to this and some other things). My question was targeted more in the direction if there is a conceptual reason or if it was an oversight that it is not displayed. I admit that this was lost in translation... Regarding the issue of not being able to see all options which are in effect for a given mount point (not specific to nocache): I consider this to be a bug. Pseudo options like "late" or "noauto" in fstab which don't make sense to use when you use mount(8) a FS by hand, I do not consider here. I'm not sure if this warrants a bug tracker item (which maybe nobody is interested to take ownership of), or if we need to extend the man pages with info which option will not by displayed in the output of mounted FS, or both. Bye, Alexander. -- http://www.Leidinger.net Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF --=_2fa80b1d684482adebd320c12be819ec Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc; size=833 Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEER9UlYXp1PSd08nWXEg2wmwP42IYFAmXsXw0ACgkQEg2wmwP4 2IaNCA//Yr+MfIg2g36NjHCTdJpuvIg3+Y9D2GGdL8zciNN/pLptqOhnNWZhHnJJ 5m6uGmgQ8lCkubkQB/OQRxLcnezBltLpTQwlW4mVheoWo76MeUKon/MWPznXanV/ bEmZFApUHcPwMgPMUuorMhxoL/WmMsOQhYdW/ZboQa0qMnV2qKoQC3XnoeIpcSyQ LkatTAuZM6slT+TcSsoPzQfPc4ad9tWWfkZjlyqhyK+Cl4FBDPkDgXN8s2KuwNou CKG4dP8kosd5808mkQx5PEHJZK6zjcbhq5Vn3V37mvCo+c/bO2MIOFnX7++CTXmg auwWco1N9LWwgyeUVo1Br/PQemC2Kz8Qg0SMYGSXvUdDFES+SI9bWbRLs0HdDciS ynRKOzT0TkXXAxMCy25rjFCTuJHg+SdGpK0L5GCwg0S71xqP7kK2f6mkLlthD0eU ZYXBwXf+/3OmlXIdhuGa/liNfjY/ZyzAlFmwSHE3PZVKIrt7SetO5/1FeeNl2bHd UWgAXmo5z7ZkFmpGnkyucgaN3OduyxKAf/oRNhNTSbUX3CLZZCmg06zGiJUuLVki QQoWZk7WUqXm1rXUUVyelVHv3QbIFxPz3h3az3IUd5/YUz5y/3/8wdbIDYgkW+n2 tkSOosBxP+jq5l2WMFLHffMO+J1Ul82tm+6rO3RmTAob0vcEP64= =A5xJ -----END PGP SIGNATURE----- --=_2fa80b1d684482adebd320c12be819ec--
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