--- a/src/viced/host.c +++ b/src/viced/host.c @@ -954,9 +954,6 @@ h_TossStuff_r(struct host *host) free(host->hcps.prlist_val); host->hcps.prlist_val = NULL; host->hcps.prlist_len = 0; - free(host->tmay_caps.Capabilities_val); - host->tmay_caps.Capabilities_val = NULL; - host->tmay_caps.Capabilities_len = 0; DeleteAllCallBacks_r(host, 1); host->hostFlags &= ~RESETDONE; /* just to be safe */ @@ -1656,210 +1653,7 @@ removeInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port) return 0; } -/* - * The following few functions deal with caching TellMeAboutYourself calls - * that we issued to clients. Why do we do this? Well: - * - * Q: First, why do we need to issue a TMAY against a client on an incoming new - * Rx connection? - * - * A: We must verify that the incoming Rx connection is the same host that - * we have a 'host' structure for. On new calls for existing connections, we - * can remember which host corresponds to that connection, but for new - * connections, we have no way to find what host it is for, except by looking - * up the host by IP address. Since hosts can change IP addresses, we need to - * contact the IP address to see if it's the host we think it is. - * - * Q: Okay, then why cache the results? - * - * A: The TMAY calls to a single host are serialized, because they are issued - * with the host's host->lock held. If we get 4 Rx calls each on new - * connections to the same host at the same time, the 1st call will lock the - * host, and issue a TMAY. Once that's done, the second call will issue a - * TMAY, then the 3rd and then the 4th. However, the 3rd and 4th calls have - * been waiting to issue a TMAY since before the 2nd call even _started_ to - * issue a TMAY. So, we can just effectively give the results of the 2nd - * call's TMAY to the 3rd and 4th, too. Since it is nondeterministic which of - * those calls gets to issue a TMAY "first", we can just assume they all got - * the same result. - * - * Note that in the above example, we cannot reuse the results of the 1st TMAY - * for the 2nd, 3rd, and 4th calls (we only reuse the results of the 2nd). - * This is because by the time the 2nd call starts waiting for the host lock, - * it doesn't know how long the 1st TMAY has been running, so the 2nd call - * might indeed get a different TMAY result (though this probably would be - * extremely rare). - * - * Anyway, so, if we don't cache the results, we are issuing TMAYs that are - * pure overhead. In an environment with clients that create a lot of - * connections to a fileserver (keep in mind each new PAG on OpenAFS clients - * creates a new connection), this can mean a significant amount of overhead. - * So, we use this "TMAY cache" to avoid this overhead for the common case. - */ -/** - * Should we skip calling TellMeAboutYourself on this host, and instead rely - * on cached TMAY results? - * - * @param[in] host The host we are dealing with - * @param[in] prewait_tmays What the value of host->n_tmays was _before_ we - * locked 'host' - * @param[in] prewait_host What the primary IP address for 'host' was before - * we locked 'host' - * @param[in] prewait_port What the primary port was for 'host' before we - * locked 'host' - * - * @return Whether we should skip calling TMAY, and instead rely on cached - * results in host - */ -static int -ShouldSkipTMAY(struct host *host, int prewait_tmays, afs_uint32 prewait_host, - afs_uint16 prewait_port) -{ - int skiptmay = 0; - if (host->n_tmays > prewait_tmays + 1) { - /* while we were waiting for the host lock, the in-progress TMAY - * call finished, someone else started a new TMAY call, and that - * finished. so, calling TMAY again won't give us any information - * or additional guarantees. */ - skiptmay = 1; - } - if (host->host != prewait_host || host->port != prewait_port) { - /* ...but don't skip it if the host has changed */ - skiptmay = 0; - } - return skiptmay; -} - -/** - * If appropriate, simulate a TellMeAboutYourself call on 'host' by extracting - * cached interfaceAddr and Capabilities information from 'host' itself. - * - * @param[in] host The host we're dealing with - * @param[inout] askiptmay On entering this function, this should contain the - * result of ShouldSkipTMAY. On return, it is 1 if we - * actually did use cached TMAY results, or 0 if we - * did not. - * @param[out] interf The interfaceAddr result of the simulated TMAY call - * @param[out] caps The Capabilities result of the simulated TMAY call - * - * @return status - * @retval 0 We used the cached TMAY results; do NOT make a real TMAY request - * @retval otherwise We did not use cached TMAY results; issue a real TMAY request - */ -static int -SimulateTMAY(struct host *host, int *askiptmay, struct interfaceAddr *interf, - Capabilities *caps) -{ - size_t capsize; - - if (!*askiptmay) { - /* we're not supposed to skip the actual TMAY call */ - return -1; - } - - *interf = host->tmay_interf; - - free(caps->Capabilities_val); - caps->Capabilities_val = NULL; - caps->Capabilities_len = 0; - - if (!host->tmay_caps.Capabilities_val) { - return 0; - } - - capsize = sizeof(caps->Capabilities_val[0]) * host->tmay_caps.Capabilities_len; - - caps->Capabilities_val = malloc(capsize); - if (!caps->Capabilities_val) { - /* we should/did _not_ skip the real TMAY call, since we couldn't - * alloc memory to use the cached results */ - *askiptmay = 0; - return -1; - } - caps->Capabilities_len = host->tmay_caps.Capabilities_len; - memcpy(caps->Capabilities_val, host->tmay_caps.Capabilities_val, capsize); - - return 0; -} - -/** - * If appropriate, store the given results from a real TellmeAboutYourself - * call, and cache them in the given host structure. - * - * @param[in] host The host we're dealing with - * @param[in] skiptmay 1 if we skipped making a real TMAY call, 0 otherwise - * @param[in] didtmay 1 if we issued a successful real TMAY call, 0 otherwise - * @param[in] interf The interfaceAddr result from the real TMAY call - * @param[in] caps The Capabilities result from the real TMAY call - */ -static void -CacheTMAY(struct host *host, int skiptmay, int didtmay, - struct interfaceAddr *interf, Capabilities *caps) -{ - size_t capsize; - - if (skiptmay) { - /* we simulated the TMAY call, so the state of the world hasn't - * changed; don't touch anything */ - return; - } - if (!didtmay) { - /* we did not perform a successful TMAY, so we don't have valid - * results to cache. blow away the existing cache so we don't use - * stale results */ - goto resetcache; - } - if (host->n_tmays == INT_MAX) { - /* make sure int rollover doesn't screw up our ordering */ - goto resetcache; - } - if (host->lock.num_waiting == 0) { - /* nobody is waiting for this host, so no reason to cache anything */ - goto resetcache; - } - - /* okay, if we got here, everything looks good; let's cache the given - * 'interf' and 'caps' */ - - host->tmay_interf = *interf; - - if (!caps->Capabilities_val) { - free(host->tmay_caps.Capabilities_val); - host->tmay_caps.Capabilities_val = NULL; - host->tmay_caps.Capabilities_len = 0; - - } else { - if (caps->Capabilities_len != host->tmay_caps.Capabilities_len) { - free(host->tmay_caps.Capabilities_val); - host->tmay_caps.Capabilities_val = NULL; - host->tmay_caps.Capabilities_len = 0; - } - - capsize = sizeof(caps->Capabilities_val[0]) * caps->Capabilities_len; - - if (!host->tmay_caps.Capabilities_val) { - host->tmay_caps.Capabilities_val = malloc(capsize); - if (!host->tmay_caps.Capabilities_val) { - goto resetcache; - } - } - - host->tmay_caps.Capabilities_len = caps->Capabilities_len; - memcpy(host->tmay_caps.Capabilities_val, caps->Capabilities_val, capsize); - } - host->n_tmays++; - return; - - resetcache: - /* blow away the cached TMAY data; pretend we never saw anything */ - free(host->tmay_caps.Capabilities_val); - host->tmay_caps.Capabilities_val = NULL; - host->tmay_caps.Capabilities_len = 0; - memset(&host->tmay_interf, 0, sizeof(host->tmay_interf)); - - host->n_tmays = 0; -} static int h_threadquota(int waiting) @@ -1910,24 +1704,12 @@ h_GetHost_r(struct rx_connection *tcon) * structure for this address. Verify that the identity * of the caller matches the identity in the host structure. */ - - int didtmay = 0; /* did we make a successful TMAY call against host->host? */ - unsigned int prewait_tmays; - afs_uint32 prewait_host; - afs_uint16 prewait_port; - int skiptmay; - if ((host->hostFlags & HWHO_INPROGRESS) && h_threadquota(host->lock.num_waiting)) { h_Release_r(host); host = NULL; goto gethost_out; } - - prewait_tmays = host->n_tmays; - prewait_host = host->host; - prewait_port = host->port; - h_Lock_r(host); if (!(host->hostFlags & ALTADDR) || (host->hostFlags & HOSTDELETED)) { @@ -1958,29 +1740,15 @@ h_GetHost_r(struct rx_connection *tcon) cb_conn = host->callback_rxcon; rx_GetConnection(cb_conn); - - skiptmay = ShouldSkipTMAY(host, prewait_tmays, prewait_host, prewait_port); - H_UNLOCK; if (haddr == host->host && hport == host->port) { /* The existing callback connection matches the * incoming connection so just use it. */ - - if (SimulateTMAY(host, &skiptmay, &interf, &caps) == 0) { - /* noop; we don't need to call TellMeAboutYourself; we can - * trust the results from the last TMAY call */ - code = 0; - - } else { - code = - RXAFSCB_TellMeAboutYourself(cb_conn, &interf, &caps); - if (code == RXGEN_OPCODE) - code = RXAFSCB_WhoAreYou(cb_conn, &interf); - if (code == 0) { - didtmay = 1; - } - } + code = + RXAFSCB_TellMeAboutYourself(cb_conn, &interf, &caps); + if (code == RXGEN_OPCODE) + code = RXAFSCB_WhoAreYou(cb_conn, &interf); } else { /* We do not have a match. Create a new connection * for the new addr/port and use multi_Rx to probe @@ -2000,9 +1768,6 @@ h_GetHost_r(struct rx_connection *tcon) rx_PutConnection(cb_conn); cb_conn=NULL; H_LOCK; - - CacheTMAY(host, skiptmay, didtmay, &interf, &caps); - if ((code == RXGEN_OPCODE) || ((code == 0) && (afs_uuid_equal(&interf.uuid, &nulluuid)))) { identP = (struct Identity *)malloc(sizeof(struct Identity)); diff --git a/src/viced/host.h b/src/viced/host.h index e0cb2f5..011bb5b 100644 --- a/src/viced/host.h +++ b/src/viced/host.h @@ -88,12 +88,6 @@ struct host { * the index fields isn't zeroed. XXX */ afs_uint32 index; /* Host table index, for vicecb.c */ - unsigned int n_tmays; /* how many successful TellMeAboutYourself calls - * have we made against this host? */ - /* cache of the result of the last successful TMAY call to this host */ - struct interfaceAddr tmay_interf; - Capabilities tmay_caps; - struct Lock lock; /* Write lock for synchronization of * VenusDown flag */ #ifdef AFS_PTHREAD_ENV