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 AF09A747F for ; Thu, 16 Oct 2025 12:32:49 +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=1760617970; cv=none; b=s8Xtt7O/BHh55BmnKJl9eBiLqhAGHw0zyIl90ZCLVG62S7A58/0uHxwEWZrNmWPPVyOCa5JoaHBqKe8FFl/RL6D8Lvcc4aMwWj+R8hQaCO/a+k5mDSYblbDjZaeGXegqZtQxdGMFkvZXMOEa+GvXsn+RBd+A7OOBBlixbyA8cUE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760617970; c=relaxed/simple; bh=ZDtamY/NCfMTPol4oHktTOyoJbfxMQcv8OAYFNFcLe0=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=VVumL6LbdcHRGye+ODCiimrydex3xG/02F2Bc1gGHR+HUV8/8/2XjfFBlIq9joAvN6sB5p2W3ajWmUUHsEK0EcngJ+cga10nUuOYHkFnmnPYnwtQfY+OcWbAUrJFcyDIJeYK6aBTtnlz2a6Kmz76CdLoRAko2ZY91F4QSuFXLU8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pPUVPTpW; 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="pPUVPTpW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B856CC4CEF1; Thu, 16 Oct 2025 12:32:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760617969; bh=ZDtamY/NCfMTPol4oHktTOyoJbfxMQcv8OAYFNFcLe0=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=pPUVPTpWP4lg01IEIuxX4xwF6pkrUX43fXEtOWpgpYNGycqfxRI16Agkimyg1ercL uw+GBbLytOEqonG9pM1syR92yX2d/5cvn/Dst55oa7vXNLs/d1xq8rzx2rpLdyXzMx yPZJIVG/dJVQ7egV8r9i8L3GZbE7gTmBColiOaKVtKqHxQFWUAGk3tbiyPI4VZCkk5 sdJScnRsGzk0QBeJPlEo3pnBsn/nQWDBgdN/xDJ/cRDsNg655QwBRyU95WC9IOZ3Ql ZxRcj9Zq42MIzSlcwFJT2IXy3NRO/r/Qs86TWtF6OBbRW8Q7PDP0uLTpLW64H+5sEC h3vLu1k5hqWyQ== Message-ID: Subject: Re: [PATCH v3 1/2] nfsd: ensure SEQUENCE replay sends a valid reply. From: Jeff Layton To: NeilBrown , Chuck Lever Cc: Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org Date: Thu, 16 Oct 2025 08:32:47 -0400 In-Reply-To: <20251016013310.2518564-2-neilb@ownmail.net> References: <20251016013310.2518564-1-neilb@ownmail.net> <20251016013310.2518564-2-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 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2025-10-16 at 12:31 +1100, NeilBrown wrote: > From: NeilBrown >=20 > nfsd4_enc_sequence_replay() uses nfsd4_encode_operation() to encode a > new SEQUENCE reply when replaying a request from the slot cache - only > ops after the SEQUENCE are replayed from the cache in ->sl_data. >=20 > However it does this in nfsd4_replay_cache_entry() which is called > *before* nfsd4_sequence() has filled in reply fields. >=20 > This means that in the replayed SEQUENCE reply: > maxslots will be whatever the client sent > target_maxslots will be -1 (assuming init to zero, and > nfsd4_encode_sequence() subtracts 1) > status_flags will be zero >=20 > The incorrect maxslots value, in particular, can cause the client to > think the slot table has been reduced in size so it can discard its > knowledge of current sequence number of the later slots, though the > server has not discarded those slots. When the client later wants to > use a later slot, it can get NFS4ERR_SEQ_MISORDERED from the server. >=20 > This patch moves the setup of the reply into a new helper function and > call it *before* nfsd4_replay_cache_entry() is called. Only one of the > updated fields was used after this point - maxslots. So the > nfsd4_sequence struct has been extended to have separate maxslots for > the request and the response. >=20 > Reported-by: Olga Kornievskaia > Closes: https://lore.kernel.org/linux-nfs/20251010194449.10281-1-okorniev= @redhat.com/ > Tested-by: Olga Kornievskaia > Signed-off-by: NeilBrown > --- > fs/nfsd/nfs4state.c | 50 ++++++++++++++++++++++++++++++--------------- > fs/nfsd/nfs4xdr.c | 2 +- > fs/nfsd/xdr4.h | 3 ++- > 3 files changed, 36 insertions(+), 19 deletions(-) >=20 > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index c9053ef4d79f..60451fd98bdf 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -4349,6 +4349,36 @@ static bool replay_matches_cache(struct svc_rqst *= rqstp, > return true; > } > =20 > +/* > + * Note that the response is constructed here both for the case > + * of a new SEQUENCE request and for a replayed SEQUENCE request. > + * We do not cache SEQUENCE responses as SEQUENCE is idempotent. > + */ > +static void nfsd4_construct_sequence_response(struct nfsd4_session *sess= ion, > + struct nfsd4_sequence *seq) > +{ > + struct nfs4_client *clp =3D session->se_client; > + > + seq->maxslots_response =3D max(session->se_target_maxslots, > + seq->maxslots); > + seq->target_maxslots =3D session->se_target_maxslots; > + > + switch (clp->cl_cb_state) { > + case NFSD4_CB_DOWN: > + seq->status_flags =3D SEQ4_STATUS_CB_PATH_DOWN; > + break; > + case NFSD4_CB_FAULT: > + seq->status_flags =3D SEQ4_STATUS_BACKCHANNEL_FAULT; > + break; > + default: > + seq->status_flags =3D 0; > + } > + if (!list_empty(&clp->cl_revoked)) > + seq->status_flags |=3D SEQ4_STATUS_RECALLABLE_STATE_REVOKED; > + if (atomic_read(&clp->cl_admin_revoked)) > + seq->status_flags |=3D SEQ4_STATUS_ADMIN_STATE_REVOKED; > +} > + > __be32 > nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *csta= te, > union nfsd4_op_u *u) > @@ -4398,6 +4428,9 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4= _compound_state *cstate, > dprintk("%s: slotid %d\n", __func__, seq->slotid); > =20 > trace_nfsd_slot_seqid_sequence(clp, seq, slot); > + > + nfsd4_construct_sequence_response(session, seq); > + > status =3D check_slot_seqid(seq->seqid, slot->sl_seqid, slot->sl_flags)= ; > if (status =3D=3D nfserr_replay_cache) { > status =3D nfserr_seq_misordered; > @@ -4495,23 +4528,6 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd= 4_compound_state *cstate, > } > =20 > out: > - seq->maxslots =3D max(session->se_target_maxslots, seq->maxslots); > - seq->target_maxslots =3D session->se_target_maxslots; > - > - switch (clp->cl_cb_state) { > - case NFSD4_CB_DOWN: > - seq->status_flags =3D SEQ4_STATUS_CB_PATH_DOWN; > - break; > - case NFSD4_CB_FAULT: > - seq->status_flags =3D SEQ4_STATUS_BACKCHANNEL_FAULT; > - break; > - default: > - seq->status_flags =3D 0; > - } > - if (!list_empty(&clp->cl_revoked)) > - seq->status_flags |=3D SEQ4_STATUS_RECALLABLE_STATE_REVOKED; > - if (atomic_read(&clp->cl_admin_revoked)) > - seq->status_flags |=3D SEQ4_STATUS_ADMIN_STATE_REVOKED; > trace_nfsd_seq4_status(rqstp, seq); > out_no_session: > if (conn) > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c > index 230bf53e39f7..6135b896b3fe 100644 > --- a/fs/nfsd/nfs4xdr.c > +++ b/fs/nfsd/nfs4xdr.c > @@ -5085,7 +5085,7 @@ nfsd4_encode_sequence(struct nfsd4_compoundres *res= p, __be32 nfserr, > return nfserr; > /* Note slotid's are numbered from zero: */ > /* sr_highest_slotid */ > - nfserr =3D nfsd4_encode_slotid4(xdr, seq->maxslots - 1); > + nfserr =3D nfsd4_encode_slotid4(xdr, seq->maxslots_response - 1); > if (nfserr !=3D nfs_ok) > return nfserr; > /* sr_target_highest_slotid */ > diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h > index ee0570cbdd9e..1ce8e12ae335 100644 > --- a/fs/nfsd/xdr4.h > +++ b/fs/nfsd/xdr4.h > @@ -574,8 +574,9 @@ struct nfsd4_sequence { > struct nfs4_sessionid sessionid; /* request/response */ > u32 seqid; /* request/response */ > u32 slotid; /* request/response */ > - u32 maxslots; /* request/response */ > + u32 maxslots; /* request */ > u32 cachethis; /* request */ > + u32 maxslots_response; /* response */ > u32 target_maxslots; /* response */ > u32 status_flags; /* response */ > }; I do like this version with the helper function better. Reviewed-by: Jeff Layton