From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 376B2C43603 for ; Thu, 12 Dec 2019 18:03:47 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DD4D5206DA for ; Thu, 12 Dec 2019 18:03:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WpVcdvX3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD4D5206DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35184 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifSoT-0000nx-Fs for qemu-devel@archiver.kernel.org; Thu, 12 Dec 2019 13:03:45 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35942) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRWw-0007f5-L7 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRWu-0004cQ-TU for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:34 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:27286 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ifRWu-0004ad-MH for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168892; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2pFimZR1BYdladtA1U9aTlDqAqMh5G97ToPYyf5Yk4g=; b=WpVcdvX3oeDWRGeazC57Il8fprjopmpO0NedNXORA23RDRB+uZNmz5OXr7PXGE120Orw29 bhoiyv4iTvsmQuKQzvLD+BSzNUnmnm1Or6a0SZ0bM7SBAu8iUQbRx+kec5k2Ri8eZz+tJk /jmWrFe1pqay+Gwn39GtNLkf76rn3MA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-255-NygvIv8QNZaRKLkkirzHfQ-1; Thu, 12 Dec 2019 11:41:31 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1BF161183E0D for ; Thu, 12 Dec 2019 16:41:30 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-226.ams2.redhat.com [10.36.116.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4228F60BE1; Thu, 12 Dec 2019 16:41:29 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 090/104] virtiofsd: rename inode->refcount to inode->nlookup Date: Thu, 12 Dec 2019 16:38:50 +0000 Message-Id: <20191212163904.159893-91-dgilbert@redhat.com> In-Reply-To: <20191212163904.159893-1-dgilbert@redhat.com> References: <20191212163904.159893-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: NygvIv8QNZaRKLkkirzHfQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Stefan Hajnoczi This reference counter plays a specific role in the FUSE protocol. It's not a generic object reference counter and the FUSE kernel code calls it "nlookup". Signed-off-by: Stefan Hajnoczi --- tools/virtiofsd/passthrough_ll.c | 37 +++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 12 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough= _ll.c index 7663e574d8..b19c9ee328 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -101,7 +101,20 @@ struct lo_inode { int fd; bool is_symlink; struct lo_key key; - uint64_t refcount; /* protected by lo->mutex */ + + /* + * This counter keeps the inode alive during the FUSE session. + * Incremented when the FUSE inode number is sent in a reply + * (FUSE_LOOKUP, FUSE_READDIRPLUS, etc). Decremented when an inode is + * released by requests like FUSE_FORGET, FUSE_RMDIR, FUSE_RENAME, etc= . + * + * Note that this value is untrusted because the client can manipulate + * it arbitrarily using FUSE_FORGET requests. + * + * Protected by lo->mutex. + */ + uint64_t nlookup; + fuse_ino_t fuse_ino; pthread_mutex_t plock_mutex; GHashTable *posix_locks; /* protected by lo_inode->plock_mutex */ @@ -570,7 +583,7 @@ retry: if (last =3D=3D path) { p =3D &lo->root; pthread_mutex_lock(&lo->mutex); - p->refcount++; + p->nlookup++; pthread_mutex_unlock(&lo->mutex); } else { *last =3D '\0'; @@ -788,8 +801,8 @@ static struct lo_inode *lo_find(struct lo_data *lo, str= uct stat *st) pthread_mutex_lock(&lo->mutex); p =3D g_hash_table_lookup(lo->inodes, &key); if (p) { - assert(p->refcount > 0); - p->refcount++; + assert(p->nlookup > 0); + p->nlookup++; } pthread_mutex_unlock(&lo->mutex); =20 @@ -857,7 +870,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t pare= nt, const char *name, } =20 inode->is_symlink =3D S_ISLNK(e->attr.st_mode); - inode->refcount =3D 1; + inode->nlookup =3D 1; inode->fd =3D newfd; newfd =3D -1; inode->key.ino =3D e->attr.st_ino; @@ -1097,7 +1110,7 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, f= use_ino_t parent, } =20 pthread_mutex_lock(&lo->mutex); - inode->refcount++; + inode->nlookup++; pthread_mutex_unlock(&lo->mutex); e.ino =3D inode->fuse_ino; =20 @@ -1226,9 +1239,9 @@ static void unref_inode_lolocked(struct lo_data *lo, = struct lo_inode *inode, } =20 pthread_mutex_lock(&lo->mutex); - assert(inode->refcount >=3D n); - inode->refcount -=3D n; - if (!inode->refcount) { + assert(inode->nlookup >=3D n); + inode->nlookup -=3D n; + if (!inode->nlookup) { lo_map_remove(&lo->ino_map, inode->fuse_ino); g_hash_table_remove(lo->inodes, &inode->key); if (g_hash_table_size(inode->posix_locks)) { @@ -1249,7 +1262,7 @@ static int unref_all_inodes_cb(gpointer key, gpointer= value, gpointer user_data) struct lo_inode *inode =3D value; struct lo_data *lo =3D user_data; =20 - inode->refcount =3D 0; + inode->nlookup =3D 0; lo_map_remove(&lo->ino_map, inode->fuse_ino); close(inode->fd); =20 @@ -1274,7 +1287,7 @@ static void lo_forget_one(fuse_req_t req, fuse_ino_t = ino, uint64_t nlookup) } =20 fuse_log(FUSE_LOG_DEBUG, " forget %lli %lli -%lli\n", - (unsigned long long)ino, (unsigned long long)inode->refcount, + (unsigned long long)ino, (unsigned long long)inode->nlookup, (unsigned long long)nlookup); =20 unref_inode_lolocked(lo, inode, nlookup); @@ -2642,7 +2655,7 @@ static void setup_root(struct lo_data *lo, struct lo_= inode *root) root->fd =3D fd; root->key.ino =3D stat.st_ino; root->key.dev =3D stat.st_dev; - root->refcount =3D 2; + root->nlookup =3D 2; } =20 static guint lo_key_hash(gconstpointer key) --=20 2.23.0