From patchwork Fri Oct 28 14:47:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13023802 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78542FA3745 for ; Fri, 28 Oct 2022 14:49:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230480AbiJ1OtJ (ORCPT ); Fri, 28 Oct 2022 10:49:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231405AbiJ1Osw (ORCPT ); Fri, 28 Oct 2022 10:48:52 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 080D41D6A65 for ; Fri, 28 Oct 2022 07:47:45 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A8387B82AA2 for ; Fri, 28 Oct 2022 14:47:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3486BC433D6; Fri, 28 Oct 2022 14:47:42 +0000 (UTC) Subject: [PATCH v7 11/14] NFSD: Clean up find_or_add_file() From: Chuck Lever To: linux-nfs@vger.kernel.org Cc: neilb@suse.de, jlayton@redhat.com Date: Fri, 28 Oct 2022 10:47:41 -0400 Message-ID: <166696846122.106044.14636201700548704756.stgit@klimt.1015granger.net> In-Reply-To: <166696812922.106044.679812521105874329.stgit@klimt.1015granger.net> References: <166696812922.106044.679812521105874329.stgit@klimt.1015granger.net> User-Agent: StGit/1.5.dev3+g9561319 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Remove the call to find_file_locked() in insert_nfs4_file(). Tracing shows that over 99% of these calls return NULL. Thus it is not worth the expense of the extra bucket list traversal. insert_file() already deals correctly with the case where the item is already in the hash bucket. Since nfsd4_file_hash_insert() is now just a wrapper around insert_file(), move the meat of insert_file() into nfsd4_file_hash_insert() and get rid of it. Signed-off-by: Chuck Lever Reviewed-by: NeilBrown --- fs/nfsd/nfs4state.c | 64 ++++++++++++++++++++++----------------------------- 1 file changed, 28 insertions(+), 36 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 504455cb80e9..b1988a46fb9b 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4683,24 +4683,42 @@ find_file_locked(const struct svc_fh *fh, unsigned int hashval) return NULL; } -static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh, - unsigned int hashval) +static struct nfs4_file * find_file(struct svc_fh *fh) { struct nfs4_file *fp; + unsigned int hashval = file_hashval(fh); + + rcu_read_lock(); + fp = find_file_locked(fh, hashval); + rcu_read_unlock(); + return fp; +} + +/* + * On hash insertion, identify entries with the same inode but + * distinct filehandles. They will all be in the same hash bucket + * because nfs4_file's are hashed by the address in the fi_inode + * field. + */ +static noinline_for_stack struct nfs4_file * +nfsd4_file_hash_insert(struct nfs4_file *new, const struct svc_fh *fhp) +{ + unsigned int hashval = file_hashval(fhp); struct nfs4_file *ret = NULL; bool alias_found = false; + struct nfs4_file *fi; spin_lock(&state_lock); - hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash, + hlist_for_each_entry_rcu(fi, &file_hashtbl[hashval], fi_hash, lockdep_is_held(&state_lock)) { - if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) { - if (refcount_inc_not_zero(&fp->fi_ref)) - ret = fp; - } else if (d_inode(fh->fh_dentry) == fp->fi_inode) - fp->fi_aliased = alias_found = true; + if (fh_match(&fi->fi_fhandle, &fhp->fh_handle)) { + if (refcount_inc_not_zero(&fi->fi_ref)) + ret = fi; + } else if (d_inode(fhp->fh_dentry) == fi->fi_inode) + fi->fi_aliased = alias_found = true; } if (likely(ret == NULL)) { - nfsd4_file_init(fh, new); + nfsd4_file_init(fhp, new); hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]); new->fi_aliased = alias_found; ret = new; @@ -4709,32 +4727,6 @@ static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh, return ret; } -static struct nfs4_file * find_file(struct svc_fh *fh) -{ - struct nfs4_file *fp; - unsigned int hashval = file_hashval(fh); - - rcu_read_lock(); - fp = find_file_locked(fh, hashval); - rcu_read_unlock(); - return fp; -} - -static struct nfs4_file * -find_or_add_file(struct nfs4_file *new, struct svc_fh *fh) -{ - struct nfs4_file *fp; - unsigned int hashval = file_hashval(fh); - - rcu_read_lock(); - fp = find_file_locked(fh, hashval); - rcu_read_unlock(); - if (fp) - return fp; - - return insert_file(new, fh, hashval); -} - static noinline_for_stack void nfsd4_file_hash_remove(struct nfs4_file *fi) { hlist_del_rcu(&fi->fi_hash); @@ -5625,7 +5617,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf * and check for delegations in the process of being recalled. * If not found, create the nfs4_file struct */ - fp = find_or_add_file(open->op_file, current_fh); + fp = nfsd4_file_hash_insert(open->op_file, current_fh); if (fp != open->op_file) { status = nfs4_check_deleg(cl, open, &dp); if (status)