Date: Fri, 24 Jun 2011 01:26:30 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Garance A Drosehn <gad@freebsd.org> Cc: freebsd-fs@freebsd.org, Robert Watson <rwatson@freebsd.org> Subject: Re: [rfc] 64-bit inode numbers Message-ID: <20110623222630.GU48734@deviant.kiev.zoral.com.ua> In-Reply-To: <4E03B8C4.6040800@FreeBSD.org> References: <20101201091203.GA3933@tops> <20110104175558.GR3140@deviant.kiev.zoral.com.ua> <20110120124108.GA32866@tops.skynet.lt> <4E027897.8080700@FreeBSD.org> <20110623064333.GA2823@tops> <20110623081140.GQ48734@deviant.kiev.zoral.com.ua> <4E03B8C4.6040800@FreeBSD.org>
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--Q5gW42QHvCgEka9W Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 23, 2011 at 06:05:56PM -0400, Garance A Drosehn wrote: > On 6/23/11 4:11 AM, Kostik Belousov wrote: > >On Thu, Jun 23, 2011 at 09:43:33AM +0300, Gleb Kurtsou wrote: > > =20 > >>On (22/06/2011 19:19), Garance A Drosehn wrote: > >> =20 > >>>Sorry for replying to an older message, but a reply made in a different > >>>thread reminded me about this project... > >>> > >>>Also, I may have asked this before. In fact, I'm almost sure that I= =20 > >>>started > >>>a reply to this back in Jan/Feb, but my email client claims I never=20 > >>>replied > >>>to this topic... > >>> > >>>Are you increasing only the size of ino_t, or could you also look at > >>>increasing the size of dev_t? (just curious...) > >>> =20 > >>Sure. Incorporating as much of similar changes as possible is good. > >>I've added Kostik and Matthew to CC list, it's for them to decide. > >> > >>dev_t on other OSes: > >> NetBSD - uint64_t > >> DragonFly - uint32_t > >> Darwin - __int32_t > >> OpenSolaris - ulong_t > >> Linux - __u32 > >> > >>Considering this I think 3rd party software is not ready for such > >>change. > >> > >>Major/minor mapping to dev_t will get more complicated. > >> > >>And the most important question: what would you want it for? [...] > >> =20 > >Indeed, this is the right question. > > =20 > Consider the thread "Increasing the size of dev_t and ino_t" from > freebsd-arch in 2002: >=20 > http://docs.freebsd.org/mail/archive/2002/freebsd-arch/20020317.freebsd-a= rch.html >=20 > In particular, this message by Robert Watson: >=20 > http://docs.freebsd.org/cgi/getmsg.cgi?fetch=3D139853+0+archive/2002/free= bsd-arch/20020317.freebsd-arch >=20 > I just participated in an online conference for OpenAFS, and while it > isn't exactly taking the world by storm, I keep thinking it would be > useful if FreeBSD could map individual AFS volumes to unique dev_t > identifiers. And given the way AFS is implemented (as a global filesystem > with many cells all reachable at the same time), and given the way most > sites deploy AFS (with thousands or tens-of-thousands of individual AFS > volumes *per site*), that adds up to a lot of values for dev_t. >=20 > The upcoming release of OpenAFS should include a working and pretty > stable AFS client for FreeBSD, so having a larger dev_t would have a > more immediate application than it did back in 2002. Am I right that the issue is the uniqueness of the dev_t for each AFS volume, as reported by stat(2) ? Shouldn't the AFS client synthesize the dev_t for each new volume mounted ? It seems that the current 32bit dev_t would be enough, since I do not expect to see hundreds of thousands of mounts on an single system. Please note that we do not guarantee dev_t stability across reboots even for real devices. --Q5gW42QHvCgEka9W Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEARECAAYFAk4DvZYACgkQC3+MBN1Mb4jJKwCgntG+O/kNjo24Tkj/LMIqSa7K C3kAoLhNjLI2rKZH7o5kfdV8Utv1CDzM =P8nv -----END PGP SIGNATURE----- --Q5gW42QHvCgEka9W--
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