From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Barbieri Subject: Re: [PATCH] Initial support for struct vfs_cred [0/1] Date: 01 Sep 2002 20:42:57 +0200 Sender: linux-fsdevel-owner@vger.kernel.org Message-ID: <1030905777.2145.91.camel@ldb> References: <1030822731.1458.127.camel@ldb> <15729.17279.474307.914587@charged.uio.no> <1030835635.1422.39.camel@ldb> <15730.4100.308481.326297@charged.uio.no> <1030890821.2145.67.camel@ldb> <15730.17012.61365.788871@charged.uio.no> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-60rKL5e8aQpiXyI0kGCd" Cc: Linus Torvalds , Linux FSdevel , Linux Kernel Return-path: To: trond.myklebust@fys.uio.no In-Reply-To: <15730.17012.61365.788871@charged.uio.no> List-Id: linux-fsdevel.vger.kernel.org --=-60rKL5e8aQpiXyI0kGCd Content-Type: text/plain Content-Transfer-Encoding: 7bit On Sun, 2002-09-01 at 18:38, Trond Myklebust wrote: > >>>>> " " == Luca Barbieri writes: > > > That's what the code did, unless I misunderstood it. Anyway if > > you want to give a different fsuid to a filesystem function, > > you either pass credentials as a parameter (that means that you > > change all the functions in the call chain to do that) or you > > If you read through the beginning of the thread, you will see that > this is *exactly* what I'm proposing to do. Just not in this one > already very large patch. But you'll need to modify the declaration of the various function pointers whose implementations might need credentials and modify all functions that call them and deal with permissions. Instead with my proposal the credentials are automatically immutable across the syscall without needing to worry at all about locks, counts and sharing. And remember that passing parameters has a cost since you need to push them and the stack will be larger, occupy more cachelines, and thus cause more cache misses. All this without any particular reason to do since normally the credentials are always the same. Of course, if you have reason to think that we'll need to call VFS functions with a lot of differential credential then you are right, but otherwise you would add just a lot of useless overhead and code modifications. --=-60rKL5e8aQpiXyI0kGCd Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.7 (GNU/Linux) iD8DBQA9cl+xdjkty3ft5+cRAkytAJ9dev8aCxyOweTOxI9rnINqhHxFMwCeLorO LpAQpSsR/69eIHDzyGUBai0= =ENs+ -----END PGP SIGNATURE----- --=-60rKL5e8aQpiXyI0kGCd--