From owner-svn-src-head@freebsd.org Tue Oct 8 11:27:49 2019 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4DDF3144992; Tue, 8 Oct 2019 11:27:49 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46nZpF1MLCz3Jl1; Tue, 8 Oct 2019 11:27:49 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 0D5AC273C7; Tue, 8 Oct 2019 11:27:49 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x98BRmEZ025292; Tue, 8 Oct 2019 11:27:48 GMT (envelope-from avg@FreeBSD.org) Received: (from avg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x98BRm1W025291; Tue, 8 Oct 2019 11:27:48 GMT (envelope-from avg@FreeBSD.org) Message-Id: <201910081127.x98BRm1W025291@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: avg set sender to avg@FreeBSD.org using -f From: Andriy Gapon Date: Tue, 8 Oct 2019 11:27:48 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r353304 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Group: head X-SVN-Commit-Author: avg X-SVN-Commit-Paths: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Commit-Revision: 353304 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Oct 2019 11:27:49 -0000 Author: avg Date: Tue Oct 8 11:27:48 2019 New Revision: 353304 URL: https://svnweb.freebsd.org/changeset/base/353304 Log: zfs: use atomic_load_64 to read atomic variable in dmu_object_alloc_impl As long as we support ZFS on 32-bit platforms we should do this for all 64-bit variables that are modified in a lockless fashion using atomic operations. Otherwise, there is a risk of a reading a torn value. Here is a rationale for why I am doing this in dmu_object_alloc_impl: - it's very recent code - the code deals with object IDs and a number of objects in a file system can overflow 32 bits - incorrect allocation of an object ID may result in hard to debug problems - fixing all plain reads of 64-bit atomic variables is not a trivial undertaking to do in one shot, so I chose to do it incrementally MFC after: 3 weeks X-MFC after: r353301, r353176 Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c Tue Oct 8 11:07:16 2019 (r353303) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c Tue Oct 8 11:27:48 2019 (r353304) @@ -76,7 +76,11 @@ dmu_object_alloc_impl(objset_t *os, dmu_object_type_t if (dnodes_per_chunk > L1_dnode_count) dnodes_per_chunk = L1_dnode_count; +#ifdef __FreeBSD__ + object = atomic_load_64(cpuobj); +#else object = *cpuobj; +#endif for (;;) { /*