Date: Thu, 10 Mar 2016 23:45:23 +0000 (UTC) From: Steven Hartland <smh@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-releng@freebsd.org Subject: svn commit: r296631 - releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201603102345.u2ANjNxX055978@repo.freebsd.org>
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Author: smh Date: Thu Mar 10 23:45:23 2016 New Revision: 296631 URL: https://svnweb.freebsd.org/changeset/base/296631 Log: MFS r296629: ZFS send fails to transmit some holes PR: 207714 Approved by: re (gjb) Sponsored by: Multiplay Modified: releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c Directory Properties: releng/10.3/ (props changed) Modified: releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c ============================================================================== --- releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c Thu Mar 10 23:37:35 2016 (r296630) +++ releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c Thu Mar 10 23:45:23 2016 (r296631) @@ -20,7 +20,7 @@ */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2013, 2014 by Delphix. All rights reserved. + * Copyright (c) 2013, 2015 by Delphix. All rights reserved. * Copyright 2014 HybridCluster. All rights reserved. */ @@ -50,6 +50,12 @@ dmu_object_alloc(objset_t *os, dmu_objec * reasonably sparse (at most 1/4 full). Look from the * beginning once, but after that keep looking from here. * If we can't find one, just keep going from here. + * + * Note that dmu_traverse depends on the behavior that we use + * multiple blocks of the dnode object before going back to + * reuse objects. Any change to this algorithm should preserve + * that property or find another solution to the issues + * described in traverse_visitbp. */ if (P2PHASE(object, L2_dnode_count) == 0) { uint64_t offset = restarted ? object << DNODE_SHIFT : 0; Modified: releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c ============================================================================== --- releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c Thu Mar 10 23:37:35 2016 (r296630) +++ releng/10.3/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c Thu Mar 10 23:45:23 2016 (r296631) @@ -20,7 +20,7 @@ */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2012, 2014 by Delphix. All rights reserved. + * Copyright (c) 2012, 2016 by Delphix. All rights reserved. * Copyright (c) 2015 Chunwei Chen. All rights reserved. */ @@ -63,6 +63,7 @@ typedef struct traverse_data { uint64_t td_hole_birth_enabled_txg; blkptr_cb_t *td_func; void *td_arg; + boolean_t td_realloc_possible; } traverse_data_t; static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp, @@ -232,18 +233,30 @@ traverse_visitbp(traverse_data_t *td, co if (bp->blk_birth == 0) { /* - * Since this block has a birth time of 0 it must be a - * hole created before the SPA_FEATURE_HOLE_BIRTH - * feature was enabled. If SPA_FEATURE_HOLE_BIRTH - * was enabled before the min_txg for this traveral we - * know the hole must have been created before the - * min_txg for this traveral, so we can skip it. If - * SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg - * for this traveral we cannot tell if the hole was - * created before or after the min_txg for this - * traversal, so we cannot skip it. + * Since this block has a birth time of 0 it must be one of + * two things: a hole created before the + * SPA_FEATURE_HOLE_BIRTH feature was enabled, or a hole + * which has always been a hole in an object. + * + * If a file is written sparsely, then the unwritten parts of + * the file were "always holes" -- that is, they have been + * holes since this object was allocated. However, we (and + * our callers) can not necessarily tell when an object was + * allocated. Therefore, if it's possible that this object + * was freed and then its object number reused, we need to + * visit all the holes with birth==0. + * + * If it isn't possible that the object number was reused, + * then if SPA_FEATURE_HOLE_BIRTH was enabled before we wrote + * all the blocks we will visit as part of this traversal, + * then this hole must have always existed, so we can skip + * it. We visit blocks born after (exclusive) td_min_txg. + * + * Note that the meta-dnode cannot be reallocated. */ - if (td->td_hole_birth_enabled_txg < td->td_min_txg) + if ((!td->td_realloc_possible || + zb->zb_object == DMU_META_DNODE_OBJECT) && + td->td_hole_birth_enabled_txg <= td->td_min_txg) return (0); } else if (bp->blk_birth <= td->td_min_txg) { return (0); @@ -338,6 +351,15 @@ traverse_visitbp(traverse_data_t *td, co objset_phys_t *osp = buf->b_data; prefetch_dnode_metadata(td, &osp->os_meta_dnode, zb->zb_objset, DMU_META_DNODE_OBJECT); + /* + * See the block comment above for the goal of this variable. + * If the maxblkid of the meta-dnode is 0, then we know that + * we've never had more than DNODES_PER_BLOCK objects in the + * dataset, which means we can't have reused any object ids. + */ + if (osp->os_meta_dnode.dn_maxblkid == 0) + td->td_realloc_possible = B_FALSE; + if (arc_buf_size(buf) >= sizeof (objset_phys_t)) { prefetch_dnode_metadata(td, &osp->os_groupused_dnode, zb->zb_objset, DMU_GROUPUSED_OBJECT); @@ -544,12 +566,13 @@ traverse_impl(spa_t *spa, dsl_dataset_t td.td_pfd = &pd; td.td_flags = flags; td.td_paused = B_FALSE; + td.td_realloc_possible = (txg_start == 0 ? B_FALSE : B_TRUE); if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) { VERIFY(spa_feature_enabled_txg(spa, SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg)); } else { - td.td_hole_birth_enabled_txg = 0; + td.td_hole_birth_enabled_txg = UINT64_MAX; } pd.pd_flags = flags;
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