From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D60B28469C for ; Wed, 19 Nov 2025 19:32:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763580740; cv=none; b=HH0DKVqhXqSLdSrJJJd2zKFH+xXAWlGkAATuq2pdMDWC9aVUkAzcUvJ1g5b5qKmrftQ0aXP2VUw83Ic193nlcx0Fq/gdn2zXQQizj9zHzKqZEAR89JT/HVyu4w88XkStQP1xSmCQic/YdubB7+bfVBW4AtuQM9VFNrNSIt4CXkI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763580740; c=relaxed/simple; bh=zriFXX8jSysvW13vJMMs9Cruc2nwBb1VyZeoYYP5w1w=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=rP7OTueF+Pt9DZ8eqE3OPdn3lFSGnTD3cmnYty3251H50TTz+FhfFN9QhJkZn+JE0ZU+ELw6oR5JfD3I+B7MOXd0jXpgp3bce0zYDVriTRbam6You75u+Tsoi/fkbCIwOyYDEb++u8QM0NMiy/FYLVkknO1gBbAxWcxAejYl9z4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z98hcrzq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Z98hcrzq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1243AC4CEF5; Wed, 19 Nov 2025 19:32:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763580737; bh=zriFXX8jSysvW13vJMMs9Cruc2nwBb1VyZeoYYP5w1w=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Z98hcrzqZCsOzhRXao6VlxxgeqQ8909XOPEQ3fi2U4y9/3ps1IEHxKxau1bN5v6Cr SAPThMUM2cMIBjCfLxyYwyeqXxTslAq1O4LMBef6QoQWKcnY1dYRS3DWXA4EgMi6hx i44bb5/FyJoIdwUdVNl4ftBSgKVLlSMaVpK1WKr4Ec7jo8303Mum/OBGi1DmOiazAS 0hxlm0gK6D4Wcyp0xityWGK1NsnNPjWVK4OXs8CEuOoMp34DmtiZ0lEK1RT+yUn0Wa 9WtLuI6l9rtA2c+HXcmz8gKYliVcuwcHkxz7HJStPp0ZVY+Mel/WQqNyhsrrgdQgB4 3iNAAbsp+vEPw== Message-ID: Subject: Re: [PATCH v5 05/11] nfsd: drop explicit tests for special stateids which would be invalid. From: Jeff Layton To: NeilBrown , Chuck Lever Cc: Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org Date: Wed, 19 Nov 2025 14:32:16 -0500 In-Reply-To: <20251119033204.360415-6-neilb@ownmail.net> References: <20251119033204.360415-1-neilb@ownmail.net> <20251119033204.360415-6-neilb@ownmail.net> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf 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Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.1 (3.58.1-1.fc43) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-11-19 at 14:28 +1100, NeilBrown wrote: > From: NeilBrown >=20 > In two places nfsd has code to test for special stateids and to report > nfserr_bad_stateid if they are found. > One is for handling TEST_STATEID ops which always forbid these stateids, > and one is for all other places that a stateid is used, and the code is > *after* any checks for special stateids which might be permitted. >=20 > These tests add no value. In each case there is a subsequent lookup for > the stateid which will return the same error code if the stateid is not > found, and special stateids never will be found. >=20 > Special stateids have a si.opaque.so_id which is either 0 or UINT_MAX. > Stateids stored in the idr only have so_id ranging from 1 or INT_MAX. > So there is no possibility of a special stateid being found. >=20 > Having the explicit test optimises the unexpected case where a special > stateid is incorrectly given, and adds unnecessary comparisons to the > common case of a non-special stateid being given. >=20 > In nfsd4_lookup_stateid(), simply removing the test would mean that > a special stateid could result in the incorrect nfserr_stale_stateid > error, as the validity of so_clid is checked before so_id. So we > add extra checks to only return nfserr_stale_stateid if the stateid > looks like it might have been locally generated - so_id not > all zeroes or all ones. >=20 > Signed-off-by: NeilBrown > --- > fs/nfsd/nfs4state.c | 33 ++++++++++++++++++++++++--------- > 1 file changed, 24 insertions(+), 9 deletions(-) >=20 > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 35004568d43e..ea931e606f40 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -74,6 +74,23 @@ static const stateid_t close_stateid =3D { > .si_generation =3D 0xffffffffU, > }; > =20 > +/* > + * In NFSv4.0 there is a case were we should return NFS4ERR_STALE_STATEI= D > + * if the stateid looks like one we might have created previously, and > + * NFS4ERR_BAD_STATEID if it looks like it was never valid. > + * There is not a lot of redundancy in the stateid that can be used to m= ake > + * this distinction, but it would be useful to differentiate special > + * stateids from locally generated stateid. > + * Special stateids have si.opaque.so_id being either all zeros or all 1= s, > + * so 0 or (u32)-1. Locally generated stateids have si.opaque.so_id as > + * a number from 1 to INT_MAX (as generated by idr_alloc_cyclic()). > + * We can test for the later range with some simple arithmetic. > + */ > +static inline bool stateid_well_formed(stateid_t *stid) > +{ > + return (stid->si_opaque.so_id - 1) < INT_MAX; > +} > + > static u64 current_sessionid =3D 1; > =20 > #define ZERO_STATEID(stateid) (!memcmp((stateid), &zero_stateid, sizeof(= stateid_t))) > @@ -7129,9 +7146,6 @@ static __be32 nfsd4_validate_stateid(struct nfs4_cl= ient *cl, stateid_t *stateid) > struct nfs4_stid *s; > __be32 status =3D nfserr_bad_stateid; > =20 > - if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) || > - CLOSE_STATEID(stateid)) > - return status; > spin_lock(&cl->cl_lock); > s =3D find_stateid_locked(cl, stateid); > if (!s) > @@ -7186,14 +7200,15 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state = *cstate, > =20 > statusmask |=3D SC_STATUS_ADMIN_REVOKED | SC_STATUS_FREEABLE; > =20 > - if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) || > - CLOSE_STATEID(stateid)) > - return nfserr_bad_stateid; > status =3D set_client(&stateid->si_opaque.so_clid, cstate, nn); > if (status =3D=3D nfserr_stale_clientid) { > - if (cstate->session) > - return nfserr_bad_stateid; > - return nfserr_stale_stateid; > + if (!cstate->session && stateid_well_formed(stateid)) > + /* > + * Might be from earlier instance - v4.0 likes > + * to know > + */ > + return nfserr_stale_stateid; > + return nfserr_bad_stateid; > } > if (status) > return status; Reviewed-by: Jeff Layton