Date: Thu, 22 Aug 2019 07:17:49 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r351383 - stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201908220717.x7M7Hnep025663@repo.freebsd.org>
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Author: avg Date: Thu Aug 22 07:17:49 2019 New Revision: 351383 URL: https://svnweb.freebsd.org/changeset/base/351383 Log: MFC r350894: a stop gap fix for a race between dnode_hold and dnode_sync_free The race was introduced in r337669, the large dnode feature import from ZoL. The problem was debugged by ZoL developers and then, independently, on FreeBSD. The fix is an early proposal by Brian Behlendorf: https://github.com/behlendorf/zfs/commit/50f32ed74e42aa28522e9681fb8ae55239fa33a7 This fix never went into ZoL. A larger change that was committed later included a different solution because of the re-worked code. Ideally, we want to revert this fix and re-synchronize FreeBSD large dnode code with that in illumos (or newer ZoL). illumos has a later import of the feature from ZoL that does not have the bug. PR: 236480 Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c ============================================================================== --- stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c Thu Aug 22 06:14:06 2019 (r351382) +++ stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c Thu Aug 22 07:17:49 2019 (r351383) @@ -1324,7 +1324,9 @@ dnode_hold_impl(objset_t *os, uint64_t object, int fla mutex_enter(&dn->dn_mtx); type = dn->dn_type; if (dn->dn_free_txg || - ((flag & DNODE_MUST_BE_FREE) && !refcount_is_zero(&dn->dn_holds))) { + ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) || + ((flag & DNODE_MUST_BE_FREE) && + (type != DMU_OT_NONE || !refcount_is_zero(&dn->dn_holds)))) { mutex_exit(&dn->dn_mtx); zrl_remove(&dnh->dnh_zrlock); dbuf_rele(db, FTAG);
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