From patchwork Fri Nov 24 00:28:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 13466960 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2a07:de40:b251:101:10:150:64:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C42BE10E3 for ; Thu, 23 Nov 2023 20:33:12 -0800 (PST) Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 2AD195BE8C; Fri, 24 Nov 2023 00:31:17 +0000 (UTC) Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 0C0911340B; Fri, 24 Nov 2023 00:31:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id naqVK9LuX2WgegAAD6G6ig (envelope-from ); Fri, 24 Nov 2023 00:31:14 +0000 From: NeilBrown To: Chuck Lever , Jeff Layton Cc: linux-nfs@vger.kernel.org, Olga Kornievskaia , Dai Ngo , Tom Talpey Subject: [PATCH 03/11] nfsd: avoid race after unhash_delegation_locked() Date: Fri, 24 Nov 2023 11:28:38 +1100 Message-ID: <20231124002925.1816-4-neilb@suse.de> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231124002925.1816-1-neilb@suse.de> References: <20231124002925.1816-1-neilb@suse.de> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spamd-Bar: +++++++++++ X-Spam-Score: 11.70 X-Rspamd-Server: rspamd1 X-Rspamd-Queue-Id: 2AD195BE8C Authentication-Results: smtp-out2.suse.de; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=suse.de (policy=none); spf=softfail (smtp-out2.suse.de: 2a07:de40:b281:104:10:150:64:97 is neither permitted nor denied by domain of neilb@suse.de) smtp.mailfrom=neilb@suse.de X-Spamd-Result: default: False [11.70 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_MISSING_CHARSET(2.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; BROKEN_CONTENT_TYPE(1.50)[]; R_SPF_SOFTFAIL(4.60)[~all:c]; RCPT_COUNT_FIVE(0.00)[6]; RCVD_COUNT_THREE(0.00)[3]; MX_GOOD(-0.01)[]; NEURAL_HAM_SHORT(-0.09)[-0.446]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(2.20)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; DMARC_POLICY_SOFTFAIL(0.10)[suse.de : No valid SPF, No valid DKIM,none] NFS4_CLOSED_DELEG_STID and NFS4_REVOKED_DELEG_STID are similar in purpose. REVOKED is used for NFSv4.1 states which have been revoked because the lease has expired. CLOSED is used in other cases. The difference has two practical effects. 1/ REVOKED states are on the ->cl_revoked list 2/ REVOKED states result in nfserr_deleg_revoked from nfsd4_verify_open_stid() asnd nfsd4_validate_stateid while CLOSED states result in nfserr_bad_stid. Currently a state that is being revoked is first set to "CLOSED" in unhash_delegation_locked(), then possibly to "REVOKED" in revoke_delegation(), at which point it is added to the cl_revoked list. It is possible that a stateid test could see the CLOSED state which really should be REVOKED, and so return the wrong error code. So it is safest to remove this window of inconsistency. With this patch, unhash_delegation_locked() always set the state correctly, and revoke_delegation() no longer changes the state. Also remove a redundant test on minorversion when NFS4_REVOKED_DELEG_STID is seen - it can only be seen when minorversion is non-zero. Reviewed-by: Jeff Layton Signed-off-by: NeilBrown --- fs/nfsd/nfs4state.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index dd01d0b9e21e..276afcba07a0 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1334,7 +1334,7 @@ static bool delegation_hashed(struct nfs4_delegation *dp) } static bool -unhash_delegation_locked(struct nfs4_delegation *dp) +unhash_delegation_locked(struct nfs4_delegation *dp, unsigned char type) { struct nfs4_file *fp = dp->dl_stid.sc_file; @@ -1343,7 +1343,9 @@ unhash_delegation_locked(struct nfs4_delegation *dp) if (!delegation_hashed(dp)) return false; - dp->dl_stid.sc_type = NFS4_CLOSED_DELEG_STID; + if (dp->dl_stid.sc_client->cl_minorversion == 0) + type = NFS4_CLOSED_DELEG_STID; + dp->dl_stid.sc_type = type; /* Ensure that deleg break won't try to requeue it */ ++dp->dl_time; spin_lock(&fp->fi_lock); @@ -1359,7 +1361,7 @@ static void destroy_delegation(struct nfs4_delegation *dp) bool unhashed; spin_lock(&state_lock); - unhashed = unhash_delegation_locked(dp); + unhashed = unhash_delegation_locked(dp, NFS4_CLOSED_DELEG_STID); spin_unlock(&state_lock); if (unhashed) destroy_unhashed_deleg(dp); @@ -1373,9 +1375,8 @@ static void revoke_delegation(struct nfs4_delegation *dp) trace_nfsd_stid_revoke(&dp->dl_stid); - if (clp->cl_minorversion) { + if (dp->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID) { spin_lock(&clp->cl_lock); - dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID; refcount_inc(&dp->dl_stid.sc_count); list_add(&dp->dl_recall_lru, &clp->cl_revoked); spin_unlock(&clp->cl_lock); @@ -2234,7 +2235,7 @@ __destroy_client(struct nfs4_client *clp) spin_lock(&state_lock); while (!list_empty(&clp->cl_delegations)) { dp = list_entry(clp->cl_delegations.next, struct nfs4_delegation, dl_perclnt); - unhash_delegation_locked(dp); + unhash_delegation_locked(dp, NFS4_CLOSED_DELEG_STID); list_add(&dp->dl_recall_lru, &reaplist); } spin_unlock(&state_lock); @@ -5196,8 +5197,7 @@ nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open, goto out; if (deleg->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID) { nfs4_put_stid(&deleg->dl_stid); - if (cl->cl_minorversion) - status = nfserr_deleg_revoked; + status = nfserr_deleg_revoked; goto out; } flags = share_access_to_flags(open->op_share_access); @@ -6234,7 +6234,7 @@ nfs4_laundromat(struct nfsd_net *nn) dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); if (!state_expired(<, dp->dl_time)) break; - unhash_delegation_locked(dp); + unhash_delegation_locked(dp, NFS4_REVOKED_DELEG_STID); list_add(&dp->dl_recall_lru, &reaplist); } spin_unlock(&state_lock); @@ -8353,7 +8353,7 @@ nfs4_state_shutdown_net(struct net *net) spin_lock(&state_lock); list_for_each_safe(pos, next, &nn->del_recall_lru) { dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); - unhash_delegation_locked(dp); + unhash_delegation_locked(dp, NFS4_CLOSED_DELEG_STID); list_add(&dp->dl_recall_lru, &reaplist); } spin_unlock(&state_lock);