Return-Path: Received: from mx142.netapp.com ([216.240.21.19]:21171 "EHLO mx142.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752117AbcLTACQ (ORCPT ); Mon, 19 Dec 2016 19:02:16 -0500 From: To: CC: , , Andy Adamson Subject: [PATCH Version 3] SVCAUTH update the rsc cache on RPC_GSS_PROC_DESTROY Date: Mon, 19 Dec 2016 19:00:30 -0500 Message-ID: <1482192030-19219-2-git-send-email-andros@netapp.com> In-Reply-To: <1482192030-19219-1-git-send-email-andros@netapp.com> References: <1482192030-19219-1-git-send-email-andros@netapp.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Andy Adamson The rsc cache code operates in a read_lock/write_lock environment. Changes to a cache entry should use the provided rsc_update routine which takes the write_lock. The current code sets the expiry_time and the CACHE_NEGATIVE flag without taking the write_lock as it does not call rsc_update. Without this patch, while cache_clean sees the entries to be removed, it does not remove the rsc_entries. This is because rsc_update sets other fields in the entry to properly trigger cache_clean. Cache_clean takes the write_lock to remove expired or invalid entries from the cache_list and calls cache_put on the entry. Looking at sunrpc_cache_update, what we want is to invalidate the cache entry, so that it is direclty replaced which means that update_rsc is called. We pass in a new zero'ed rsc cache entry to rsc_update with an expiry_time set to 0 along with the invalidatedcache entry to be destroyed. The cache_put at the end of svcauth_gss_accept processing drops the reference count to 1 which allows the cache_put called by cache_clean to result in a call to rsc_put and rsc_free to reap the entry after it has been removed from the cache_list under the write_lock. Signed-off-by: Andy Adamson --- net/sunrpc/auth_gss/svcauth_gss.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 45662d7..b8093da 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -1409,7 +1409,9 @@ static void destroy_use_gss_proxy_proc_entry(struct net *net) {} u32 crlen; struct gss_svc_data *svcdata = rqstp->rq_auth_data; struct rpc_gss_wire_cred *gc; - struct rsc *rsci = NULL; + struct rsc *rsci = NULL, new = { + .mechctx = 0, + }; __be32 *rpcstart; __be32 *reject_stat = resv->iov_base + resv->iov_len; int ret; @@ -1489,10 +1491,20 @@ static void destroy_use_gss_proxy_proc_entry(struct net *net) {} case RPC_GSS_PROC_DESTROY: if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq)) goto auth_err; - rsci->h.expiry_time = get_seconds(); - set_bit(CACHE_NEGATIVE, &rsci->h.flags); + + /** Invalidate the cache entry so sunrpc_update_cache + * direclty updates rsci. new->h.expiry_time is zero, + * so rsci->h.expiry_time will be set to zero and + * cache_clean will properly remove rsci. + */ + clear_bit(CACHE_VALID, &rsci->h.flags); + rsci = rsc_update(sn->rsc_cache, &new, rsci); + if (!rsci) + goto drop; + if (resv->iov_len + 4 > PAGE_SIZE) goto drop; + svc_putnl(resv, RPC_SUCCESS); goto complete; case RPC_GSS_PROC_DATA: -- 1.8.3.1