Attachment #167864 for bug #207714

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Lines 20-26 Link Here

(-)./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c (-1 / +7 lines)
20	*/	20	*/
21	/*	21	/*
22	* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.	22	* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23	* Copyright (c) 2013, 2014 by Delphix. All rights reserved.	23	* Copyright (c) 2013, 2015 by Delphix. All rights reserved.
24	* Copyright 2014 HybridCluster. All rights reserved.	24	* Copyright 2014 HybridCluster. All rights reserved.
25	*/	25	*/
26		26
Lines 50-55 Link Here
50	* reasonably sparse (at most 1/4 full). Look from the	50	* reasonably sparse (at most 1/4 full). Look from the
51	* beginning once, but after that keep looking from here.	51	* beginning once, but after that keep looking from here.
52	* If we can't find one, just keep going from here.	52	* If we can't find one, just keep going from here.
		53	*
		54	* Note that dmu_traverse depends on the behavior that we use
		55	* multiple blocks of the dnode object before going back to
		56	* reuse objects. Any change to this algorithm should preserve
		57	* that property or find another solution to the issues described
		58	* in traverse_visitbp.
53	*/	59	*/
54	if (P2PHASE(object, L2_dnode_count) == 0) {	60	if (P2PHASE(object, L2_dnode_count) == 0) {
55	uint64_t offset = restarted ? object << DNODE_SHIFT : 0;	61	uint64_t offset = restarted ? object << DNODE_SHIFT : 0;




 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
 * Copyright (c) 2015 Chunwei Chen. All rights reserved.
 */


	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,


	if (bp->blk_birth == 0) {
		/*
		 * 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.  This occurs when an object is created and then
		 * a write is performed that leaves part of the file as zeroes.
		 * Normally we don't care about this case, but if this object
		 * has the same object number as an object that has been
		 * destroyed, callers of dmu_traverse may not be able to tell
		 * that the object has been recreated.  Thus, we must give them
		 * all of the holes with birth == 0 in any objects that may have
		 * been recreated. Thus, we cannot skip the block if it is
		 * possible the object has been recreated. If it isn't, then if
		 * SPA_FEATURE_HOLE_BIRTH was enabled before the min_txg for
		 * this traversal we know the hole must have been created before
		 * the min_txg for this traversal, so we can skip it. If
		 * SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg for this
		 * traversal we cannot tell if the hole was created before or
		 * after the min_txg for this traversal, so we cannot skip it.
		 * Note that the meta-dnode cannot be reallocated, so we needn't
		 * worry about that case.
		 */
		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);

		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);

	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 = UINT64_MAX;
	}

	pd.pd_flags = flags;

Return to bug 207714

Lines 20-26 Link Here

(-)./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c (-13 / +36 lines)
20	*/	20	*/
21	/*	21	/*
22	* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.	22	* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23	* Copyright (c) 2012, 2014 by Delphix. All rights reserved.	23	* Copyright (c) 2012, 2016 by Delphix. All rights reserved.
24	* Copyright (c) 2015 Chunwei Chen. All rights reserved.	24	* Copyright (c) 2015 Chunwei Chen. All rights reserved.
25	*/	25	*/
26		26
Lines 63-68 Link Here
63	uint64_t td_hole_birth_enabled_txg;	63	uint64_t td_hole_birth_enabled_txg;
64	blkptr_cb_t *td_func;	64	blkptr_cb_t *td_func;
65	void *td_arg;	65	void *td_arg;
		66	boolean_t td_realloc_possible;
66	} traverse_data_t;	67	} traverse_data_t;
67		68
68	static int traverse_dnode(traverse_data_t td, const dnode_phys_t dnp,	69	static int traverse_dnode(traverse_data_t td, const dnode_phys_t dnp,
Lines 232-249 Link Here
232		233
233	if (bp->blk_birth == 0) {	234	if (bp->blk_birth == 0) {
234	/*	235	/*
235	* Since this block has a birth time of 0 it must be a	236	* Since this block has a birth time of 0 it must be one of two
236	* hole created before the SPA_FEATURE_HOLE_BIRTH	237	* things: a hole created before the SPA_FEATURE_HOLE_BIRTH
237	* feature was enabled. If SPA_FEATURE_HOLE_BIRTH	238	* feature was enabled, or a hole which has always been a hole
238	* was enabled before the min_txg for this traveral we	239	* in an object. This occurs when an object is created and then
239	* know the hole must have been created before the	240	* a write is performed that leaves part of the file as zeroes.
240	* min_txg for this traveral, so we can skip it. If	241	* Normally we don't care about this case, but if this object
241	* SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg	242	* has the same object number as an object that has been
242	* for this traveral we cannot tell if the hole was	243	* destroyed, callers of dmu_traverse may not be able to tell
243	* created before or after the min_txg for this	244	* that the object has been recreated. Thus, we must give them
244	* traversal, so we cannot skip it.	245	* all of the holes with birth == 0 in any objects that may have
		246	* been recreated. Thus, we cannot skip the block if it is
		247	* possible the object has been recreated. If it isn't, then if
		248	* SPA_FEATURE_HOLE_BIRTH was enabled before the min_txg for
		249	* this traversal we know the hole must have been created before
		250	* the min_txg for this traversal, so we can skip it. If
		251	* SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg for this
		252	* traversal we cannot tell if the hole was created before or
		253	* after the min_txg for this traversal, so we cannot skip it.
		254	* Note that the meta-dnode cannot be reallocated, so we needn't
		255	* worry about that case.
245	*/	256	*/
246	if (td->td_hole_birth_enabled_txg < td->td_min_txg)	257	if ((!td->td_realloc_possible \|\|
		258	zb->zb_object == DMU_META_DNODE_OBJECT) &&
		259	td->td_hole_birth_enabled_txg <= td->td_min_txg)
247	return (0);	260	return (0);
248	} else if (bp->blk_birth <= td->td_min_txg) {	261	} else if (bp->blk_birth <= td->td_min_txg) {
249	return (0);	262	return (0);
Lines 338-343 Link Here
338	objset_phys_t *osp = buf->b_data;	351	objset_phys_t *osp = buf->b_data;
339	prefetch_dnode_metadata(td, &osp->os_meta_dnode, zb->zb_objset,	352	prefetch_dnode_metadata(td, &osp->os_meta_dnode, zb->zb_objset,
340	DMU_META_DNODE_OBJECT);	353	DMU_META_DNODE_OBJECT);
		354	/*
		355	* See the block comment above for the goal of this variable.
		356	* If the maxblkid of the meta-dnode is 0, then we know that
		357	* we've never had more than DNODES_PER_BLOCK objects in the
		358	* dataset, which means we can't have reused any object ids.
		359	*/
		360	if (osp->os_meta_dnode.dn_maxblkid == 0)
		361	td->td_realloc_possible = B_FALSE;
		362
341	if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {	363	if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {
342	prefetch_dnode_metadata(td, &osp->os_groupused_dnode,	364	prefetch_dnode_metadata(td, &osp->os_groupused_dnode,
343	zb->zb_objset, DMU_GROUPUSED_OBJECT);	365	zb->zb_objset, DMU_GROUPUSED_OBJECT);
Lines 544-555 Link Here
544	td.td_pfd = &pd;	566	td.td_pfd = &pd;
545	td.td_flags = flags;	567	td.td_flags = flags;
546	td.td_paused = B_FALSE;	568	td.td_paused = B_FALSE;
		569	td.td_realloc_possible = (txg_start == 0 ? B_FALSE : B_TRUE);
547		570
548	if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {	571	if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
549	VERIFY(spa_feature_enabled_txg(spa,	572	VERIFY(spa_feature_enabled_txg(spa,
550	SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg));	573	SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg));
551	} else {	574	} else {
552	td.td_hole_birth_enabled_txg = 0;	575	td.td_hole_birth_enabled_txg = UINT64_MAX;
553	}	576	}
554		577
555	pd.pd_flags = flags;	578	pd.pd_flags = flags;