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 ED6901E32BE for ; Mon, 3 Mar 2025 18:05:11 +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=1741025112; cv=none; b=f3vlbEN11v8UO4lciquOIYMsSRSUEk/rZ+ZUrdcbVPH1WyheheXzYA5fM/T1nxnKUx+kjCDUoO/0yvdyuVM+bzRk64aixqIa1G3S+bh8OsGQzdVWS+fC7nN0rbXuhFpoXFgHaC4Qd8i/v/2YKjrJJ3J4r4Tx4H5PvR0L7GCaqdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741025112; c=relaxed/simple; bh=v46zj0TJVhOMNVTlZ9QLwIVuhS27jOz3eIqrvnGcHRY=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Gyw+QnWCxvWICz+isvFV4gh4ZX2sX9WOunIFMD2AsTrqSTTNReCrqH0udE0lcogR4coRAjQwL7+M8kwx5M8DKyHiHJuLRl8TX5+YreFiEYlaqC+oh5t0uMCHNBaFqH44BIhOQQqL5eMGu3aCPg8drQvpRP8lyrCXBFFBK6gJRZw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gTFfC2pL; 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="gTFfC2pL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A092EC4CED6; Mon, 3 Mar 2025 18:05:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741025111; bh=v46zj0TJVhOMNVTlZ9QLwIVuhS27jOz3eIqrvnGcHRY=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=gTFfC2pLJMl/4ddhhijQNyvUN8ZMssf0nGK0eEgknLpJLIc1UyGZ0Rj2tlGTOGVS9 8zWlbjn+PDgvjcq1NpHtvdSRv1PucnU83SnT37dnPTWImKhLSaOMJSHrLT8jT0xB5+ lwXwGLgGlW5aw3jGGYaSQX2KYf7fWN1P/Kf2PVyduyX4QZ2L0oWUw6J7AaROfmRDak Tw55db6XN5FpzWMB2yz7wHCRKbLZ2lxdP9XKBHyG6vfZJG3bOUH0MlxZQ4JAmDTu5G FYRvBGi0nDpgEXQOFHQ3vVZkNwDO01kJe3Hs/0LP/iEMQ8wkjsQWMJEKkhAugCPp0C KpKTSqze+EivA== Message-ID: Subject: Re: [PATCH v2 3/5] NFSD: Implement CB_SEQUENCE referring call lists From: Jeff Layton To: cel@kernel.org, Neil Brown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: linux-nfs@vger.kernel.org, Chuck Lever Date: Mon, 03 Mar 2025 13:05:09 -0500 In-Reply-To: <20250301183151.11362-4-cel@kernel.org> References: <20250301183151.11362-1-cel@kernel.org> <20250301183151.11362-4-cel@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 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We have yet to implement a mechanism in NFSD for resolving races > between a server's reply and a related callback operation. For > example, a CB_OFFLOAD callback can race with the matching COPY > response. The client will not recognize the copy state ID in the > CB_OFFLOAD callback until the COPY response arrives. >=20 > Trond adds: > > It is also needed for the same kind of race with delegation > > recalls, layout recalls, CB_NOTIFY_DEVICEID and would also be > > helpful (although not as strongly required) for CB_NOTIFY_LOCK. >=20 > RFC 8881 Section 20.9.3 describes referring call lists this way: > > The csa_referring_call_lists array is the list of COMPOUND > > requests, identified by session ID, slot ID, and sequence ID. > > These are requests that the client previously sent to the server. > > These previous requests created state that some operation(s) in > > the same CB_COMPOUND as the csa_referring_call_lists are > > identifying. A session ID is included because leased state is tied > > to a client ID, and a client ID can have multiple sessions. See > > Section 2.10.6.3. >=20 > Introduce the XDR infrastructure for populating the > csa_referring_call_lists argument of CB_SEQUENCE. Subsequent patches > will put the referring call list to use. >=20 > Note that cb_sequence_enc_sz estimates that only zero or one rcl is > included in each CB_SEQUENCE, but the new infrastructure can > manage any number of referring calls. >=20 > Signed-off-by: Chuck Lever > --- > fs/nfsd/nfs4callback.c | 132 +++++++++++++++++++++++++++++++++++++++-- > fs/nfsd/state.h | 22 +++++++ > fs/nfsd/xdr4cb.h | 5 +- > 3 files changed, 153 insertions(+), 6 deletions(-) >=20 > diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c > index 484077200c5d..f1fffff69330 100644 > --- a/fs/nfsd/nfs4callback.c > +++ b/fs/nfsd/nfs4callback.c > @@ -419,6 +419,29 @@ static u32 highest_slotid(struct nfsd4_session *ses) > return idx; > } > =20 > +static void > +encode_referring_call4(struct xdr_stream *xdr, > + const struct nfsd4_referring_call *rc) > +{ > + encode_uint32(xdr, rc->rc_sequenceid); > + encode_uint32(xdr, rc->rc_slotid); > +} > + > +static void > +encode_referring_call_list4(struct xdr_stream *xdr, > + const struct nfsd4_referring_call_list *rcl) > +{ > + struct nfsd4_referring_call *rc; > + __be32 *p; > + > + p =3D xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN); > + xdr_encode_opaque_fixed(p, rcl->rcl_sessionid.data, > + NFS4_MAX_SESSIONID_LEN); > + encode_uint32(xdr, rcl->__nr_referring_calls); > + list_for_each_entry(rc, &rcl->rcl_referring_calls, __list) > + encode_referring_call4(xdr, rc); > +} > + > /* > * CB_SEQUENCE4args > * > @@ -436,6 +459,7 @@ static void encode_cb_sequence4args(struct xdr_stream= *xdr, > struct nfs4_cb_compound_hdr *hdr) > { > struct nfsd4_session *session =3D cb->cb_clp->cl_cb_session; > + struct nfsd4_referring_call_list *rcl; > __be32 *p; > =20 > if (hdr->minorversion =3D=3D 0) > @@ -444,12 +468,16 @@ static void encode_cb_sequence4args(struct xdr_stre= am *xdr, > encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE); > encode_sessionid4(xdr, session); > =20 > - p =3D xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4); > + p =3D xdr_reserve_space(xdr, XDR_UNIT * 4); > *p++ =3D cpu_to_be32(session->se_cb_seq_nr[cb->cb_held_slot]); /* csa_s= equenceid */ > *p++ =3D cpu_to_be32(cb->cb_held_slot); /* csa_slotid */ > *p++ =3D cpu_to_be32(highest_slotid(session)); /* csa_highest_slotid */ > *p++ =3D xdr_zero; /* csa_cachethis */ > - xdr_encode_empty_array(p); /* csa_referring_call_lists */ > + > + /* csa_referring_call_lists */ > + encode_uint32(xdr, cb->cb_nr_referring_call_list); > + list_for_each_entry(rcl, &cb->cb_referring_call_list, __list) > + encode_referring_call_list4(xdr, rcl); > =20 > hdr->nops++; > } > @@ -1306,10 +1334,102 @@ static void nfsd41_destroy_cb(struct nfsd4_callb= ack *cb) > nfsd41_cb_inflight_end(clp); > } > =20 > -/* > - * TODO: cb_sequence should support referring call lists, cachethis, > - * and mark callback channel down on communication errors. > +/** > + * nfsd41_cb_referring_call - add a referring call to a callback operati= on > + * @cb: context of callback to add the rc to > + * @sessionid: referring call's session ID > + * @slotid: referring call's session slot index > + * @seqno: referring call's slot sequence number > + * > + * Caller serializes access to @cb. > + * > + * NB: If memory allocation fails, the referring call is not added. > */ > +void nfsd41_cb_referring_call(struct nfsd4_callback *cb, > + struct nfs4_sessionid *sessionid, > + u32 slotid, u32 seqno) > +{ > + struct nfsd4_referring_call_list *rcl; > + struct nfsd4_referring_call *rc; > + bool found; > + > + might_sleep(); > + > + found =3D false; > + list_for_each_entry(rcl, &cb->cb_referring_call_list, __list) { > + if (!memcmp(rcl->rcl_sessionid.data, sessionid->data, > + NFS4_MAX_SESSIONID_LEN)) { > + found =3D true; > + break; > + } > + } > + if (!found) { > + rcl =3D kmalloc(sizeof(*rcl), GFP_KERNEL); > + if (!rcl) > + return; > + memcpy(rcl->rcl_sessionid.data, sessionid->data, > + NFS4_MAX_SESSIONID_LEN); > + rcl->__nr_referring_calls =3D 0; > + INIT_LIST_HEAD(&rcl->rcl_referring_calls); > + list_add(&rcl->__list, &cb->cb_referring_call_list); > + cb->cb_nr_referring_call_list++; > + } > + > + found =3D false; > + list_for_each_entry(rc, &rcl->rcl_referring_calls, __list) { > + if (rc->rc_sequenceid =3D=3D seqno && rc->rc_slotid =3D=3D slotid) { > + found =3D true; > + break; > + } > + } > + if (!found) { > + rc =3D kmalloc(sizeof(*rc), GFP_KERNEL); > + if (!rc) > + goto out; > + rc->rc_sequenceid =3D seqno; > + rc->rc_slotid =3D slotid; > + rcl->__nr_referring_calls++; > + list_add(&rc->__list, &rcl->rcl_referring_calls); > + } > + > +out: > + if (!rcl->__nr_referring_calls) { > + cb->cb_nr_referring_call_list--; > + kfree(rcl); > + } > +} > + > +/** > + * nfsd41_cb_destroy_referring_call_list - release referring call info > + * @cb: context of a callback that has completed > + * > + * Callers who allocate referring calls using nfsd41_cb_referring_call()= must > + * release those resources by calling nfsd41_cb_destroy_referring_call_l= ist. > + * > + * Caller serializes access to @cb. > + */ > +void nfsd41_cb_destroy_referring_call_list(struct nfsd4_callback *cb) > +{ > + struct nfsd4_referring_call_list *rcl; > + struct nfsd4_referring_call *rc; > + > + while (!list_empty(&cb->cb_referring_call_list)) { > + rcl =3D list_first_entry(&cb->cb_referring_call_list, > + struct nfsd4_referring_call_list, > + __list); > + > + while (!list_empty(&rcl->rcl_referring_calls)) { > + rc =3D list_first_entry(&rcl->rcl_referring_calls, > + struct nfsd4_referring_call, > + __list); > + list_del(&rc->__list); > + kfree(rc); > + } > + list_del(&rcl->__list); > + kfree(rcl); > + } > +} > + > static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata) > { > struct nfsd4_callback *cb =3D calldata; > @@ -1625,6 +1745,8 @@ void nfsd4_init_cb(struct nfsd4_callback *cb, struc= t nfs4_client *clp, > cb->cb_status =3D 0; > cb->cb_need_restart =3D false; > cb->cb_held_slot =3D -1; > + cb->cb_nr_referring_call_list =3D 0; > + INIT_LIST_HEAD(&cb->cb_referring_call_list); > } > =20 > /** > diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h > index 74d2d7b42676..b4af840fc4f9 100644 > --- a/fs/nfsd/state.h > +++ b/fs/nfsd/state.h > @@ -64,6 +64,21 @@ typedef struct { > refcount_t cs_count; > } copy_stateid_t; > =20 > +struct nfsd4_referring_call { > + struct list_head __list; > + > + u32 rc_sequenceid; > + u32 rc_slotid; > +}; > + > +struct nfsd4_referring_call_list { > + struct list_head __list; > + > + struct nfs4_sessionid rcl_sessionid; > + int __nr_referring_calls; > + struct list_head rcl_referring_calls; > +}; > + This set of nested lists is rather complex. Did you consider keeping a single list and just adding the sessionid to nfsd4_referring_call? I suppose that might mean you'd have to do more sessionid comparisons but in general, I'd expect these lists to be short. > struct nfsd4_callback { > struct nfs4_client *cb_clp; > struct rpc_message cb_msg; > @@ -73,6 +88,9 @@ struct nfsd4_callback { > int cb_status; > int cb_held_slot; > bool cb_need_restart; > + > + int cb_nr_referring_call_list; > + struct list_head cb_referring_call_list; > }; > =20 > struct nfsd4_callback_ops { > @@ -777,6 +795,10 @@ extern __be32 nfs4_check_open_reclaim(struct nfs4_cl= ient *); > extern void nfsd4_probe_callback(struct nfs4_client *clp); > extern void nfsd4_probe_callback_sync(struct nfs4_client *clp); > extern void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_c= b_conn *); > +extern void nfsd41_cb_referring_call(struct nfsd4_callback *cb, > + struct nfs4_sessionid *sessionid, > + u32 slotid, u32 seqno); > +extern void nfsd41_cb_destroy_referring_call_list(struct nfsd4_callback = *cb); > extern void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client = *clp, > const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op); > extern bool nfsd4_run_cb(struct nfsd4_callback *cb); > diff --git a/fs/nfsd/xdr4cb.h b/fs/nfsd/xdr4cb.h > index f1a315cd31b7..f4e29c0c701c 100644 > --- a/fs/nfsd/xdr4cb.h > +++ b/fs/nfsd/xdr4cb.h > @@ -6,8 +6,11 @@ > #define cb_compound_enc_hdr_sz 4 > #define cb_compound_dec_hdr_sz (3 + (NFS4_MAXTAGLEN >> 2)) > #define sessionid_sz (NFS4_MAX_SESSIONID_LEN >> 2) > +#define enc_referring_call4_sz (1 + 1) > +#define enc_referring_call_list4_sz (sessionid_sz + 1 + \ > + enc_referring_call4_sz) > #define cb_sequence_enc_sz (sessionid_sz + 4 + \ > - 1 /* no referring calls list yet */) > + enc_referring_call_list4_sz) > #define cb_sequence_dec_sz (op_dec_sz + sessionid_sz + 4) > =20 > #define op_enc_sz 1 --=20 Jeff Layton