From nobody Fri Nov 17 01:52:04 2023 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4SWfz85S5kz51LWn; Fri, 17 Nov 2023 01:52:04 +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 4SWfz8511Yz3Tnd; Fri, 17 Nov 2023 01:52:04 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1700185924; 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; bh=8AAMuFeuQvRI2QerCadM8adqOFDxMZYuK/cgoHc6sNU=; b=reGn0Y8oTkzrIFfHAuwHpQIo5jH8eQbzkuHit8TAnQZeLc1i4PLE2wKfltcobkexX7RF0h Xa4QaowKM9e26erBwaJiDVuYEo8xF2ilCktipnDriX1YlUtACWrXrTl89wdFT/9n3RRVYw m0YMmU4TtXcF6XwCV4oQyW5uFg+c+th8DsKsmemZAeKyE1bliHKJJUHTz3Pg7q5Bs2UP1N j2i2qteCct7kTBO2Ky0FaNpmdq4GxGDSAw+OMuptRl/YleuMMSsgsitIWoVHAOfJLiQ//X YttapuNADKZYGviszr9ZoKztX49J2+WcCwSBUH57y8FLp7KCFwPMbdBKgutppg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1700185924; 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; bh=8AAMuFeuQvRI2QerCadM8adqOFDxMZYuK/cgoHc6sNU=; b=NzO+VTfBEOGQyPFNmKZluE+awA32rIT5n0yOa5GYMdXdVMGQsSd8RyyrmEN0lZPwVSKHbx mHXVUv2XKZ/CXFSZDcOQCZsr5poOUU5qR1U5B72PbUAm6/zS6HRaJ1r1V8sAIHzrplzeeK KX/uBzUlLAXL+dDE+9yczrgdxDdtvICwc1LHhF+F8Ql2luOXbmdZtGgsSTDEDyHBE0VUuM sKI9k2VK62oycLFLJydgbXP8qN1F3e/EZlbmWsg8hmJEe3ooIpHYkZ5ecJxsRB9yNllTyY KuIvvstpM5GHe2k5/+nRTSUXGaNfJUGjiWOgaAUMjaKegC2fBLG5iZlYL9AfrA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1700185924; a=rsa-sha256; cv=none; b=A98bxeJfBRsuoiEF6oX7oKz+Eb/HBqjAUBWlocdGzgIP6Eq4CdZQnshV9sBQWiq551sHzV h5o35ifCrsAw93OzSQrmP/y3Wz62QJsyswNRFMotl/TmBpnd3h1CM7v+xtcGWCACtU+ubS ycGanWd3L1xXfQwC8lLb53WV5EToqWTQK5h4q3lVxH3g76kMGndmxZZNf8uZrwP1NdQcMd Wj8kBHGMGR0ryYpvikxTSBZU2r0YdHP6cOGAWnavDbQEoxjW2u6So+0AvwURAsUax5pJ6G BZVrBFoyAZb/dMkAS5y/OxpDNs+ECuzp3I+iA0Bv2KpCSZF3t0vlZa25JYyrzA== 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 4SWfz844m2z8X9; Fri, 17 Nov 2023 01:52:04 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.17.1/8.17.1) with ESMTP id 3AH1q4xV047930; Fri, 17 Nov 2023 01:52:04 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.17.1/8.17.1/Submit) id 3AH1q4hl047927; Fri, 17 Nov 2023 01:52:04 GMT (envelope-from git) Date: Fri, 17 Nov 2023 01:52:04 GMT Message-Id: <202311170152.3AH1q4hl047927@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Konstantin Belousov Subject: git: 22bac49b09a9 - main - vn_lock_pair(): reasonably handle vp1 == vp2 case List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kib X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 22bac49b09a9f975330dc0d811436599ce740890 Auto-Submitted: auto-generated The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=22bac49b09a9f975330dc0d811436599ce740890 commit 22bac49b09a9f975330dc0d811436599ce740890 Author: Konstantin Belousov AuthorDate: 2023-11-16 22:42:25 +0000 Commit: Konstantin Belousov CommitDate: 2023-11-17 01:51:41 +0000 vn_lock_pair(): reasonably handle vp1 == vp2 case Lock the vnode in the most exclusive lock mode requested, once. All callers already ensure that vp1 != vp2 or are careful enough to only unlock once otherwise. Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D42642 --- sys/kern/vfs_vnops.c | 41 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 36 insertions(+), 5 deletions(-) diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c index 27ce5401f15f..f81516608eeb 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -4042,10 +4042,10 @@ vn_lock_pair_pause(const char *wmesg) } /* - * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. - * vp1_locked indicates whether vp1 is locked; if not, vp1 must be - * unlocked. Same for vp2 and vp2_locked. One of the vnodes can be - * NULL. + * Lock pair of (possibly same) vnodes vp1, vp2, avoiding lock order + * reversal. vp1_locked indicates whether vp1 is locked; if not, vp1 + * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes + * can be NULL. * * The function returns with both vnodes exclusively or shared locked, * according to corresponding lkflags, and guarantees that it does not @@ -4056,12 +4056,14 @@ vn_lock_pair_pause(const char *wmesg) * * Only one of LK_SHARED and LK_EXCLUSIVE must be specified. * LK_NODDLKTREAT can be optionally passed. + * + * If vp1 == vp2, only one, most exclusive, lock is obtained on it. */ void vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1, struct vnode *vp2, bool vp2_locked, int lkflags2) { - int error; + int error, locked1; MPASS(((lkflags1 & LK_SHARED) != 0) ^ ((lkflags1 & LK_EXCLUSIVE) != 0)); MPASS((lkflags1 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); @@ -4071,6 +4073,35 @@ vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1, if (vp1 == NULL && vp2 == NULL) return; + if (vp1 == vp2) { + MPASS(vp1_locked == vp2_locked); + + /* Select the most exclusive mode for lock. */ + if ((lkflags1 & LK_TYPE_MASK) != (lkflags2 & LK_TYPE_MASK)) + lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE; + + if (vp1_locked) { + ASSERT_VOP_LOCKED(vp1, "vp1"); + + /* No need to relock if any lock is exclusive. */ + if ((vp1->v_vnlock->lock_object.lo_flags & + LK_NOSHARE) != 0) + return; + + locked1 = VOP_ISLOCKED(vp1); + if (((lkflags1 & LK_SHARED) != 0 && + locked1 != LK_EXCLUSIVE) || + ((lkflags1 & LK_EXCLUSIVE) != 0 && + locked1 == LK_EXCLUSIVE)) + return; + VOP_UNLOCK(vp1); + } + + ASSERT_VOP_UNLOCKED(vp1, "vp1"); + vn_lock(vp1, lkflags1 | LK_RETRY); + return; + } + if (vp1 != NULL) { if ((lkflags1 & LK_SHARED) != 0 && (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0)