From owner-dev-commits-src-branches@freebsd.org Sat May 22 18:31:03 2021 Return-Path: Delivered-To: dev-commits-src-branches@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 495F963489D; Sat, 22 May 2021 18:31:03 +0000 (UTC) (envelope-from git@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) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4FnX9M1XHsz4Z8p; Sat, 22 May 2021 18:31:03 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 1B9671227; Sat, 22 May 2021 18:31:03 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 14MIV3H7017989; Sat, 22 May 2021 18:31:03 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 14MIV3qC017988; Sat, 22 May 2021 18:31:03 GMT (envelope-from git) Date: Sat, 22 May 2021 18:31:03 GMT Message-Id: <202105221831.14MIV3qC017988@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mateusz Guzik Subject: git: d2e0a3bb2194 - stable/13 - zfs: damage control racing .. lookups in face of mkdir/rmdir MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mjg X-Git-Repository: src X-Git-Refname: refs/heads/stable/13 X-Git-Reftype: branch X-Git-Commit: d2e0a3bb2194f1d938aacbd48afbab758f9f2314 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-branches@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commits to the stable branches of the FreeBSD src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 22 May 2021 18:31:03 -0000 The branch stable/13 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=d2e0a3bb2194f1d938aacbd48afbab758f9f2314 commit d2e0a3bb2194f1d938aacbd48afbab758f9f2314 Author: Mateusz Guzik AuthorDate: 2021-04-15 07:54:18 +0000 Commit: Mateusz Guzik CommitDate: 2021-05-22 18:30:44 +0000 zfs: damage control racing .. lookups in face of mkdir/rmdir Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D29769 (cherry picked from commit 9c651561a2a31fcb08390d37947afc27ec03d87b) --- .../openzfs/module/os/freebsd/zfs/zfs_vnops_os.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c index 8172916c4329..a1e9c359b893 100644 --- a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c +++ b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c @@ -781,6 +781,7 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, znode_t *zdp = VTOZ(dvp); znode_t *zp; zfsvfs_t *zfsvfs = zdp->z_zfsvfs; + seqc_t dvp_seqc; int error = 0; /* @@ -806,6 +807,8 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zdp); + dvp_seqc = vn_seqc_read_any(dvp); + *vpp = NULL; if (flags & LOOKUP_XATTR) { @@ -975,6 +978,24 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, } } + if ((cnp->cn_flags & ISDOTDOT) != 0) { + /* + * FIXME: zfs_lookup_lock relocks vnodes and does nothing to + * handle races. In particular different callers may end up + * with different vnodes and will try to add conflicting + * entries to the namecache. + * + * While finding different result may be acceptable in face + * of concurrent modification, adding conflicting entries + * trips over an assert in the namecache. + * + * Ultimately let an entry through once everything settles. + */ + if (!vn_seqc_consistent(dvp, dvp_seqc)) { + cnp->cn_flags &= ~MAKEENTRY; + } + } + /* Insert name into cache (as non-existent) if appropriate. */ if (zfsvfs->z_use_namecache && !zfsvfs->z_replay && error == ENOENT && (cnp->cn_flags & MAKEENTRY) != 0)