xref: /freebsd/sys/contrib/openzfs/module/zfs/dmu_traverse.c (revision dbd5678dca91abcefe8d046aa2f9b66497a95ffb)
1eda14cbcSMatt Macy /*
2eda14cbcSMatt Macy  * CDDL HEADER START
3eda14cbcSMatt Macy  *
4eda14cbcSMatt Macy  * The contents of this file are subject to the terms of the
5eda14cbcSMatt Macy  * Common Development and Distribution License (the "License").
6eda14cbcSMatt Macy  * You may not use this file except in compliance with the License.
7eda14cbcSMatt Macy  *
8eda14cbcSMatt Macy  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9271171e0SMartin Matuska  * or https://opensource.org/licenses/CDDL-1.0.
10eda14cbcSMatt Macy  * See the License for the specific language governing permissions
11eda14cbcSMatt Macy  * and limitations under the License.
12eda14cbcSMatt Macy  *
13eda14cbcSMatt Macy  * When distributing Covered Code, include this CDDL HEADER in each
14eda14cbcSMatt Macy  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15eda14cbcSMatt Macy  * If applicable, add the following below this CDDL HEADER, with the
16eda14cbcSMatt Macy  * fields enclosed by brackets "[]" replaced with your own identifying
17eda14cbcSMatt Macy  * information: Portions Copyright [yyyy] [name of copyright owner]
18eda14cbcSMatt Macy  *
19eda14cbcSMatt Macy  * CDDL HEADER END
20eda14cbcSMatt Macy  */
21eda14cbcSMatt Macy /*
22eda14cbcSMatt Macy  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23eda14cbcSMatt Macy  * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
24eda14cbcSMatt Macy  */
25eda14cbcSMatt Macy 
26eda14cbcSMatt Macy #include <sys/zfs_context.h>
27eda14cbcSMatt Macy #include <sys/dmu_objset.h>
28eda14cbcSMatt Macy #include <sys/dmu_traverse.h>
29eda14cbcSMatt Macy #include <sys/dsl_dataset.h>
30eda14cbcSMatt Macy #include <sys/dsl_dir.h>
31eda14cbcSMatt Macy #include <sys/dsl_pool.h>
32eda14cbcSMatt Macy #include <sys/dnode.h>
33eda14cbcSMatt Macy #include <sys/spa.h>
34eda14cbcSMatt Macy #include <sys/spa_impl.h>
35eda14cbcSMatt Macy #include <sys/zio.h>
36eda14cbcSMatt Macy #include <sys/dmu_impl.h>
37eda14cbcSMatt Macy #include <sys/sa.h>
38eda14cbcSMatt Macy #include <sys/sa_impl.h>
39eda14cbcSMatt Macy #include <sys/callb.h>
40eda14cbcSMatt Macy #include <sys/zfeature.h>
41eda14cbcSMatt Macy 
42e92ffd9bSMartin Matuska static int32_t zfs_pd_bytes_max = 50 * 1024 * 1024;	/* 50MB */
43e92ffd9bSMartin Matuska static int32_t send_holes_without_birth_time = 1;
44be181ee2SMartin Matuska static uint_t zfs_traverse_indirect_prefetch_limit = 32;
45eda14cbcSMatt Macy 
46eda14cbcSMatt Macy typedef struct prefetch_data {
47eda14cbcSMatt Macy 	kmutex_t pd_mtx;
48eda14cbcSMatt Macy 	kcondvar_t pd_cv;
49eda14cbcSMatt Macy 	int32_t pd_bytes_fetched;
50eda14cbcSMatt Macy 	int pd_flags;
51eda14cbcSMatt Macy 	boolean_t pd_cancel;
52eda14cbcSMatt Macy 	boolean_t pd_exited;
53eda14cbcSMatt Macy 	zbookmark_phys_t pd_resume;
54eda14cbcSMatt Macy } prefetch_data_t;
55eda14cbcSMatt Macy 
56eda14cbcSMatt Macy typedef struct traverse_data {
57eda14cbcSMatt Macy 	spa_t *td_spa;
58eda14cbcSMatt Macy 	uint64_t td_objset;
59eda14cbcSMatt Macy 	blkptr_t *td_rootbp;
60eda14cbcSMatt Macy 	uint64_t td_min_txg;
61eda14cbcSMatt Macy 	zbookmark_phys_t *td_resume;
62eda14cbcSMatt Macy 	int td_flags;
63eda14cbcSMatt Macy 	prefetch_data_t *td_pfd;
64eda14cbcSMatt Macy 	boolean_t td_paused;
65eda14cbcSMatt Macy 	uint64_t td_hole_birth_enabled_txg;
66eda14cbcSMatt Macy 	blkptr_cb_t *td_func;
67eda14cbcSMatt Macy 	void *td_arg;
68eda14cbcSMatt Macy 	boolean_t td_realloc_possible;
69eda14cbcSMatt Macy } traverse_data_t;
70eda14cbcSMatt Macy 
71eda14cbcSMatt Macy static int traverse_dnode(traverse_data_t *td, const blkptr_t *bp,
72eda14cbcSMatt Macy     const dnode_phys_t *dnp, uint64_t objset, uint64_t object);
73eda14cbcSMatt Macy static void prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *,
74eda14cbcSMatt Macy     uint64_t objset, uint64_t object);
75eda14cbcSMatt Macy 
76eda14cbcSMatt Macy static int
77180f8225SMatt Macy traverse_zil_block(zilog_t *zilog, const blkptr_t *bp, void *arg,
78180f8225SMatt Macy     uint64_t claim_txg)
79eda14cbcSMatt Macy {
80eda14cbcSMatt Macy 	traverse_data_t *td = arg;
81eda14cbcSMatt Macy 	zbookmark_phys_t zb;
82eda14cbcSMatt Macy 
83eda14cbcSMatt Macy 	if (BP_IS_HOLE(bp))
84eda14cbcSMatt Macy 		return (0);
85eda14cbcSMatt Macy 
86eda14cbcSMatt Macy 	if (claim_txg == 0 && bp->blk_birth >= spa_min_claim_txg(td->td_spa))
87eda14cbcSMatt Macy 		return (-1);
88eda14cbcSMatt Macy 
89eda14cbcSMatt Macy 	SET_BOOKMARK(&zb, td->td_objset, ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
90eda14cbcSMatt Macy 	    bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
91eda14cbcSMatt Macy 
92eda14cbcSMatt Macy 	(void) td->td_func(td->td_spa, zilog, bp, &zb, NULL, td->td_arg);
93eda14cbcSMatt Macy 
94eda14cbcSMatt Macy 	return (0);
95eda14cbcSMatt Macy }
96eda14cbcSMatt Macy 
97eda14cbcSMatt Macy static int
98180f8225SMatt Macy traverse_zil_record(zilog_t *zilog, const lr_t *lrc, void *arg,
99180f8225SMatt Macy     uint64_t claim_txg)
100eda14cbcSMatt Macy {
101eda14cbcSMatt Macy 	traverse_data_t *td = arg;
102eda14cbcSMatt Macy 
103eda14cbcSMatt Macy 	if (lrc->lrc_txtype == TX_WRITE) {
104eda14cbcSMatt Macy 		lr_write_t *lr = (lr_write_t *)lrc;
105eda14cbcSMatt Macy 		blkptr_t *bp = &lr->lr_blkptr;
106eda14cbcSMatt Macy 		zbookmark_phys_t zb;
107eda14cbcSMatt Macy 
108eda14cbcSMatt Macy 		if (BP_IS_HOLE(bp))
109eda14cbcSMatt Macy 			return (0);
110eda14cbcSMatt Macy 
111eda14cbcSMatt Macy 		if (claim_txg == 0 || bp->blk_birth < claim_txg)
112eda14cbcSMatt Macy 			return (0);
113eda14cbcSMatt Macy 
114*dbd5678dSMartin Matuska 		ASSERT3U(BP_GET_LSIZE(bp), !=, 0);
115eda14cbcSMatt Macy 		SET_BOOKMARK(&zb, td->td_objset, lr->lr_foid,
116eda14cbcSMatt Macy 		    ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
117eda14cbcSMatt Macy 
118eda14cbcSMatt Macy 		(void) td->td_func(td->td_spa, zilog, bp, &zb, NULL,
119eda14cbcSMatt Macy 		    td->td_arg);
120eda14cbcSMatt Macy 	}
121eda14cbcSMatt Macy 	return (0);
122eda14cbcSMatt Macy }
123eda14cbcSMatt Macy 
124eda14cbcSMatt Macy static void
125eda14cbcSMatt Macy traverse_zil(traverse_data_t *td, zil_header_t *zh)
126eda14cbcSMatt Macy {
127eda14cbcSMatt Macy 	uint64_t claim_txg = zh->zh_claim_txg;
128eda14cbcSMatt Macy 
129eda14cbcSMatt Macy 	/*
130eda14cbcSMatt Macy 	 * We only want to visit blocks that have been claimed but not yet
131eda14cbcSMatt Macy 	 * replayed; plus blocks that are already stable in read-only mode.
132eda14cbcSMatt Macy 	 */
133eda14cbcSMatt Macy 	if (claim_txg == 0 && spa_writeable(td->td_spa))
134eda14cbcSMatt Macy 		return;
135eda14cbcSMatt Macy 
136eda14cbcSMatt Macy 	zilog_t *zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
137eda14cbcSMatt Macy 	(void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
138eda14cbcSMatt Macy 	    claim_txg, !(td->td_flags & TRAVERSE_NO_DECRYPT));
139eda14cbcSMatt Macy 	zil_free(zilog);
140eda14cbcSMatt Macy }
141eda14cbcSMatt Macy 
142eda14cbcSMatt Macy typedef enum resume_skip {
143eda14cbcSMatt Macy 	RESUME_SKIP_ALL,
144eda14cbcSMatt Macy 	RESUME_SKIP_NONE,
145eda14cbcSMatt Macy 	RESUME_SKIP_CHILDREN
146eda14cbcSMatt Macy } resume_skip_t;
147eda14cbcSMatt Macy 
148eda14cbcSMatt Macy /*
149eda14cbcSMatt Macy  * Returns RESUME_SKIP_ALL if td indicates that we are resuming a traversal and
150eda14cbcSMatt Macy  * the block indicated by zb does not need to be visited at all. Returns
151eda14cbcSMatt Macy  * RESUME_SKIP_CHILDREN if we are resuming a post traversal and we reach the
152eda14cbcSMatt Macy  * resume point. This indicates that this block should be visited but not its
153eda14cbcSMatt Macy  * children (since they must have been visited in a previous traversal).
154eda14cbcSMatt Macy  * Otherwise returns RESUME_SKIP_NONE.
155eda14cbcSMatt Macy  */
156eda14cbcSMatt Macy static resume_skip_t
157eda14cbcSMatt Macy resume_skip_check(traverse_data_t *td, const dnode_phys_t *dnp,
158eda14cbcSMatt Macy     const zbookmark_phys_t *zb)
159eda14cbcSMatt Macy {
160eda14cbcSMatt Macy 	if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume)) {
161eda14cbcSMatt Macy 		/*
162eda14cbcSMatt Macy 		 * If we already visited this bp & everything below,
163eda14cbcSMatt Macy 		 * don't bother doing it again.
164eda14cbcSMatt Macy 		 */
165eda14cbcSMatt Macy 		if (zbookmark_subtree_completed(dnp, zb, td->td_resume))
166eda14cbcSMatt Macy 			return (RESUME_SKIP_ALL);
167eda14cbcSMatt Macy 
168eda14cbcSMatt Macy 		/*
169eda14cbcSMatt Macy 		 * If we found the block we're trying to resume from, zero
170eda14cbcSMatt Macy 		 * the bookmark out to indicate that we have resumed.
171eda14cbcSMatt Macy 		 */
172da5137abSMartin Matuska 		if (memcmp(zb, td->td_resume, sizeof (*zb)) == 0) {
173da5137abSMartin Matuska 			memset(td->td_resume, 0, sizeof (*zb));
174eda14cbcSMatt Macy 			if (td->td_flags & TRAVERSE_POST)
175eda14cbcSMatt Macy 				return (RESUME_SKIP_CHILDREN);
176eda14cbcSMatt Macy 		}
177eda14cbcSMatt Macy 	}
178eda14cbcSMatt Macy 	return (RESUME_SKIP_NONE);
179eda14cbcSMatt Macy }
180eda14cbcSMatt Macy 
18116038816SMartin Matuska /*
18216038816SMartin Matuska  * Returns B_TRUE, if prefetch read is issued, otherwise B_FALSE.
18316038816SMartin Matuska  */
18416038816SMartin Matuska static boolean_t
185eda14cbcSMatt Macy traverse_prefetch_metadata(traverse_data_t *td,
186eda14cbcSMatt Macy     const blkptr_t *bp, const zbookmark_phys_t *zb)
187eda14cbcSMatt Macy {
188eda14cbcSMatt Macy 	arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
189eda14cbcSMatt Macy 	int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
190eda14cbcSMatt Macy 
191eda14cbcSMatt Macy 	if (!(td->td_flags & TRAVERSE_PREFETCH_METADATA))
19216038816SMartin Matuska 		return (B_FALSE);
193eda14cbcSMatt Macy 	/*
194eda14cbcSMatt Macy 	 * If we are in the process of resuming, don't prefetch, because
195eda14cbcSMatt Macy 	 * some children will not be needed (and in fact may have already
196eda14cbcSMatt Macy 	 * been freed).
197eda14cbcSMatt Macy 	 */
198eda14cbcSMatt Macy 	if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume))
19916038816SMartin Matuska 		return (B_FALSE);
200eda14cbcSMatt Macy 	if (BP_IS_HOLE(bp) || bp->blk_birth <= td->td_min_txg)
20116038816SMartin Matuska 		return (B_FALSE);
202eda14cbcSMatt Macy 	if (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE)
20316038816SMartin Matuska 		return (B_FALSE);
204eda14cbcSMatt Macy 	ASSERT(!BP_IS_REDACTED(bp));
205eda14cbcSMatt Macy 
206eda14cbcSMatt Macy 	if ((td->td_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
207eda14cbcSMatt Macy 		zio_flags |= ZIO_FLAG_RAW;
208eda14cbcSMatt Macy 
209eda14cbcSMatt Macy 	(void) arc_read(NULL, td->td_spa, bp, NULL, NULL,
210eda14cbcSMatt Macy 	    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
21116038816SMartin Matuska 	return (B_TRUE);
212eda14cbcSMatt Macy }
213eda14cbcSMatt Macy 
214eda14cbcSMatt Macy static boolean_t
215eda14cbcSMatt Macy prefetch_needed(prefetch_data_t *pfd, const blkptr_t *bp)
216eda14cbcSMatt Macy {
217eda14cbcSMatt Macy 	ASSERT(pfd->pd_flags & TRAVERSE_PREFETCH_DATA);
218eda14cbcSMatt Macy 	if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp) ||
219eda14cbcSMatt Macy 	    BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG || BP_IS_REDACTED(bp))
220eda14cbcSMatt Macy 		return (B_FALSE);
221eda14cbcSMatt Macy 	return (B_TRUE);
222eda14cbcSMatt Macy }
223eda14cbcSMatt Macy 
224eda14cbcSMatt Macy static int
225eda14cbcSMatt Macy traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
226eda14cbcSMatt Macy     const blkptr_t *bp, const zbookmark_phys_t *zb)
227eda14cbcSMatt Macy {
228eda14cbcSMatt Macy 	int err = 0;
229eda14cbcSMatt Macy 	arc_buf_t *buf = NULL;
230eda14cbcSMatt Macy 	prefetch_data_t *pd = td->td_pfd;
231eda14cbcSMatt Macy 
232eda14cbcSMatt Macy 	switch (resume_skip_check(td, dnp, zb)) {
233eda14cbcSMatt Macy 	case RESUME_SKIP_ALL:
234eda14cbcSMatt Macy 		return (0);
235eda14cbcSMatt Macy 	case RESUME_SKIP_CHILDREN:
236eda14cbcSMatt Macy 		goto post;
237eda14cbcSMatt Macy 	case RESUME_SKIP_NONE:
238eda14cbcSMatt Macy 		break;
239eda14cbcSMatt Macy 	default:
240eda14cbcSMatt Macy 		ASSERT(0);
241eda14cbcSMatt Macy 	}
242eda14cbcSMatt Macy 
243eda14cbcSMatt Macy 	if (bp->blk_birth == 0) {
244eda14cbcSMatt Macy 		/*
245eda14cbcSMatt Macy 		 * Since this block has a birth time of 0 it must be one of
246eda14cbcSMatt Macy 		 * two things: a hole created before the
247eda14cbcSMatt Macy 		 * SPA_FEATURE_HOLE_BIRTH feature was enabled, or a hole
248eda14cbcSMatt Macy 		 * which has always been a hole in an object.
249eda14cbcSMatt Macy 		 *
250eda14cbcSMatt Macy 		 * If a file is written sparsely, then the unwritten parts of
251eda14cbcSMatt Macy 		 * the file were "always holes" -- that is, they have been
252eda14cbcSMatt Macy 		 * holes since this object was allocated.  However, we (and
253eda14cbcSMatt Macy 		 * our callers) can not necessarily tell when an object was
254eda14cbcSMatt Macy 		 * allocated.  Therefore, if it's possible that this object
255eda14cbcSMatt Macy 		 * was freed and then its object number reused, we need to
256eda14cbcSMatt Macy 		 * visit all the holes with birth==0.
257eda14cbcSMatt Macy 		 *
258eda14cbcSMatt Macy 		 * If it isn't possible that the object number was reused,
259eda14cbcSMatt Macy 		 * then if SPA_FEATURE_HOLE_BIRTH was enabled before we wrote
260eda14cbcSMatt Macy 		 * all the blocks we will visit as part of this traversal,
261eda14cbcSMatt Macy 		 * then this hole must have always existed, so we can skip
262eda14cbcSMatt Macy 		 * it.  We visit blocks born after (exclusive) td_min_txg.
263eda14cbcSMatt Macy 		 *
264eda14cbcSMatt Macy 		 * Note that the meta-dnode cannot be reallocated.
265eda14cbcSMatt Macy 		 */
266eda14cbcSMatt Macy 		if (!send_holes_without_birth_time &&
267eda14cbcSMatt Macy 		    (!td->td_realloc_possible ||
268eda14cbcSMatt Macy 		    zb->zb_object == DMU_META_DNODE_OBJECT) &&
269eda14cbcSMatt Macy 		    td->td_hole_birth_enabled_txg <= td->td_min_txg)
270eda14cbcSMatt Macy 			return (0);
271eda14cbcSMatt Macy 	} else if (bp->blk_birth <= td->td_min_txg) {
272eda14cbcSMatt Macy 		return (0);
273eda14cbcSMatt Macy 	}
274eda14cbcSMatt Macy 
275eda14cbcSMatt Macy 	if (pd != NULL && !pd->pd_exited && prefetch_needed(pd, bp)) {
276eda14cbcSMatt Macy 		uint64_t size = BP_GET_LSIZE(bp);
277eda14cbcSMatt Macy 		mutex_enter(&pd->pd_mtx);
278eda14cbcSMatt Macy 		ASSERT(pd->pd_bytes_fetched >= 0);
279eda14cbcSMatt Macy 		while (pd->pd_bytes_fetched < size && !pd->pd_exited)
280eda14cbcSMatt Macy 			cv_wait_sig(&pd->pd_cv, &pd->pd_mtx);
281eda14cbcSMatt Macy 		pd->pd_bytes_fetched -= size;
282eda14cbcSMatt Macy 		cv_broadcast(&pd->pd_cv);
283eda14cbcSMatt Macy 		mutex_exit(&pd->pd_mtx);
284eda14cbcSMatt Macy 	}
285eda14cbcSMatt Macy 
286eda14cbcSMatt Macy 	if (BP_IS_HOLE(bp) || BP_IS_REDACTED(bp)) {
287eda14cbcSMatt Macy 		err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
288eda14cbcSMatt Macy 		if (err != 0)
289eda14cbcSMatt Macy 			goto post;
290eda14cbcSMatt Macy 		return (0);
291eda14cbcSMatt Macy 	}
292eda14cbcSMatt Macy 
293eda14cbcSMatt Macy 	if (td->td_flags & TRAVERSE_PRE) {
294eda14cbcSMatt Macy 		err = td->td_func(td->td_spa, NULL, bp, zb, dnp,
295eda14cbcSMatt Macy 		    td->td_arg);
296eda14cbcSMatt Macy 		if (err == TRAVERSE_VISIT_NO_CHILDREN)
297eda14cbcSMatt Macy 			return (0);
298eda14cbcSMatt Macy 		if (err != 0)
299eda14cbcSMatt Macy 			goto post;
300eda14cbcSMatt Macy 	}
301eda14cbcSMatt Macy 
302eda14cbcSMatt Macy 	if (BP_GET_LEVEL(bp) > 0) {
303eda14cbcSMatt Macy 		uint32_t flags = ARC_FLAG_WAIT;
30416038816SMartin Matuska 		int32_t i, ptidx, pidx;
30516038816SMartin Matuska 		uint32_t prefetchlimit;
306eda14cbcSMatt Macy 		int32_t epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
307eda14cbcSMatt Macy 		zbookmark_phys_t *czb;
308eda14cbcSMatt Macy 
309eda14cbcSMatt Macy 		ASSERT(!BP_IS_PROTECTED(bp));
310eda14cbcSMatt Macy 
311eda14cbcSMatt Macy 		err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
312eda14cbcSMatt Macy 		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
313eda14cbcSMatt Macy 		if (err != 0)
314eda14cbcSMatt Macy 			goto post;
315eda14cbcSMatt Macy 
316eda14cbcSMatt Macy 		czb = kmem_alloc(sizeof (zbookmark_phys_t), KM_SLEEP);
317eda14cbcSMatt Macy 
31816038816SMartin Matuska 		/*
31916038816SMartin Matuska 		 * When performing a traversal it is beneficial to
32016038816SMartin Matuska 		 * asynchronously read-ahead the upcoming indirect
32116038816SMartin Matuska 		 * blocks since they will be needed shortly. However,
32216038816SMartin Matuska 		 * since a 128k indirect (non-L0) block may contain up
32316038816SMartin Matuska 		 * to 1024 128-byte block pointers, its preferable to not
32416038816SMartin Matuska 		 * prefetch them all at once. Issuing a large number of
32516038816SMartin Matuska 		 * async reads may effect performance, and the earlier
32616038816SMartin Matuska 		 * the indirect blocks are prefetched the less likely
32716038816SMartin Matuska 		 * they are to still be resident in the ARC when needed.
32816038816SMartin Matuska 		 * Therefore, prefetching indirect blocks is limited to
32916038816SMartin Matuska 		 * zfs_traverse_indirect_prefetch_limit=32 blocks by
33016038816SMartin Matuska 		 * default.
33116038816SMartin Matuska 		 *
33216038816SMartin Matuska 		 * pidx: Index for which next prefetch to be issued.
33316038816SMartin Matuska 		 * ptidx: Index at which next prefetch to be triggered.
33416038816SMartin Matuska 		 */
33516038816SMartin Matuska 		ptidx = 0;
33616038816SMartin Matuska 		pidx = 1;
33716038816SMartin Matuska 		prefetchlimit = zfs_traverse_indirect_prefetch_limit;
338eda14cbcSMatt Macy 		for (i = 0; i < epb; i++) {
33916038816SMartin Matuska 			if (prefetchlimit && i == ptidx) {
34016038816SMartin Matuska 				ASSERT3S(ptidx, <=, pidx);
34116038816SMartin Matuska 				for (uint32_t  prefetched = 0; pidx < epb &&
34216038816SMartin Matuska 				    prefetched < prefetchlimit; pidx++) {
34316038816SMartin Matuska 					SET_BOOKMARK(czb, zb->zb_objset,
34416038816SMartin Matuska 					    zb->zb_object, zb->zb_level - 1,
34516038816SMartin Matuska 					    zb->zb_blkid * epb + pidx);
34616038816SMartin Matuska 					if (traverse_prefetch_metadata(td,
34716038816SMartin Matuska 					    &((blkptr_t *)buf->b_data)[pidx],
34816038816SMartin Matuska 					    czb) == B_TRUE) {
34916038816SMartin Matuska 						prefetched++;
35016038816SMartin Matuska 						if (prefetched ==
35116038816SMartin Matuska 						    MAX(prefetchlimit / 2, 1))
35216038816SMartin Matuska 							ptidx = pidx;
35316038816SMartin Matuska 					}
35416038816SMartin Matuska 				}
355eda14cbcSMatt Macy 			}
356eda14cbcSMatt Macy 
357eda14cbcSMatt Macy 			/* recursively visitbp() blocks below this */
358eda14cbcSMatt Macy 			SET_BOOKMARK(czb, zb->zb_objset, zb->zb_object,
359eda14cbcSMatt Macy 			    zb->zb_level - 1,
360eda14cbcSMatt Macy 			    zb->zb_blkid * epb + i);
361eda14cbcSMatt Macy 			err = traverse_visitbp(td, dnp,
362eda14cbcSMatt Macy 			    &((blkptr_t *)buf->b_data)[i], czb);
363eda14cbcSMatt Macy 			if (err != 0)
364eda14cbcSMatt Macy 				break;
365eda14cbcSMatt Macy 		}
366eda14cbcSMatt Macy 
367eda14cbcSMatt Macy 		kmem_free(czb, sizeof (zbookmark_phys_t));
368eda14cbcSMatt Macy 
369eda14cbcSMatt Macy 	} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
370eda14cbcSMatt Macy 		uint32_t flags = ARC_FLAG_WAIT;
371eda14cbcSMatt Macy 		uint32_t zio_flags = ZIO_FLAG_CANFAIL;
372eda14cbcSMatt Macy 		int32_t i;
373eda14cbcSMatt Macy 		int32_t epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
374eda14cbcSMatt Macy 		dnode_phys_t *child_dnp;
375eda14cbcSMatt Macy 
376eda14cbcSMatt Macy 		/*
377eda14cbcSMatt Macy 		 * dnode blocks might have their bonus buffers encrypted, so
378eda14cbcSMatt Macy 		 * we must be careful to honor TRAVERSE_NO_DECRYPT
379eda14cbcSMatt Macy 		 */
380eda14cbcSMatt Macy 		if ((td->td_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
381eda14cbcSMatt Macy 			zio_flags |= ZIO_FLAG_RAW;
382eda14cbcSMatt Macy 
383eda14cbcSMatt Macy 		err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
384eda14cbcSMatt Macy 		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
385eda14cbcSMatt Macy 		if (err != 0)
386eda14cbcSMatt Macy 			goto post;
387eda14cbcSMatt Macy 
388eda14cbcSMatt Macy 		child_dnp = buf->b_data;
389eda14cbcSMatt Macy 
390eda14cbcSMatt Macy 		for (i = 0; i < epb; i += child_dnp[i].dn_extra_slots + 1) {
391eda14cbcSMatt Macy 			prefetch_dnode_metadata(td, &child_dnp[i],
392eda14cbcSMatt Macy 			    zb->zb_objset, zb->zb_blkid * epb + i);
393eda14cbcSMatt Macy 		}
394eda14cbcSMatt Macy 
395eda14cbcSMatt Macy 		/* recursively visitbp() blocks below this */
396eda14cbcSMatt Macy 		for (i = 0; i < epb; i += child_dnp[i].dn_extra_slots + 1) {
397eda14cbcSMatt Macy 			err = traverse_dnode(td, bp, &child_dnp[i],
398eda14cbcSMatt Macy 			    zb->zb_objset, zb->zb_blkid * epb + i);
399eda14cbcSMatt Macy 			if (err != 0)
400eda14cbcSMatt Macy 				break;
401eda14cbcSMatt Macy 		}
402eda14cbcSMatt Macy 	} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
403eda14cbcSMatt Macy 		uint32_t zio_flags = ZIO_FLAG_CANFAIL;
404eda14cbcSMatt Macy 		arc_flags_t flags = ARC_FLAG_WAIT;
405eda14cbcSMatt Macy 		objset_phys_t *osp;
406eda14cbcSMatt Macy 
407eda14cbcSMatt Macy 		if ((td->td_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
408eda14cbcSMatt Macy 			zio_flags |= ZIO_FLAG_RAW;
409eda14cbcSMatt Macy 
410eda14cbcSMatt Macy 		err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
411eda14cbcSMatt Macy 		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
412eda14cbcSMatt Macy 		if (err != 0)
413eda14cbcSMatt Macy 			goto post;
414eda14cbcSMatt Macy 
415eda14cbcSMatt Macy 		osp = buf->b_data;
416eda14cbcSMatt Macy 		prefetch_dnode_metadata(td, &osp->os_meta_dnode, zb->zb_objset,
417eda14cbcSMatt Macy 		    DMU_META_DNODE_OBJECT);
418eda14cbcSMatt Macy 		/*
419eda14cbcSMatt Macy 		 * See the block comment above for the goal of this variable.
420eda14cbcSMatt Macy 		 * If the maxblkid of the meta-dnode is 0, then we know that
421eda14cbcSMatt Macy 		 * we've never had more than DNODES_PER_BLOCK objects in the
422eda14cbcSMatt Macy 		 * dataset, which means we can't have reused any object ids.
423eda14cbcSMatt Macy 		 */
424eda14cbcSMatt Macy 		if (osp->os_meta_dnode.dn_maxblkid == 0)
425eda14cbcSMatt Macy 			td->td_realloc_possible = B_FALSE;
426eda14cbcSMatt Macy 
427eda14cbcSMatt Macy 		if (OBJSET_BUF_HAS_USERUSED(buf)) {
428eda14cbcSMatt Macy 			if (OBJSET_BUF_HAS_PROJECTUSED(buf))
429eda14cbcSMatt Macy 				prefetch_dnode_metadata(td,
430eda14cbcSMatt Macy 				    &osp->os_projectused_dnode,
431eda14cbcSMatt Macy 				    zb->zb_objset, DMU_PROJECTUSED_OBJECT);
432eda14cbcSMatt Macy 			prefetch_dnode_metadata(td, &osp->os_groupused_dnode,
433eda14cbcSMatt Macy 			    zb->zb_objset, DMU_GROUPUSED_OBJECT);
434eda14cbcSMatt Macy 			prefetch_dnode_metadata(td, &osp->os_userused_dnode,
435eda14cbcSMatt Macy 			    zb->zb_objset, DMU_USERUSED_OBJECT);
436eda14cbcSMatt Macy 		}
437eda14cbcSMatt Macy 
438eda14cbcSMatt Macy 		err = traverse_dnode(td, bp, &osp->os_meta_dnode, zb->zb_objset,
439eda14cbcSMatt Macy 		    DMU_META_DNODE_OBJECT);
440eda14cbcSMatt Macy 		if (err == 0 && OBJSET_BUF_HAS_USERUSED(buf)) {
441eda14cbcSMatt Macy 			if (OBJSET_BUF_HAS_PROJECTUSED(buf))
442eda14cbcSMatt Macy 				err = traverse_dnode(td, bp,
443eda14cbcSMatt Macy 				    &osp->os_projectused_dnode, zb->zb_objset,
444eda14cbcSMatt Macy 				    DMU_PROJECTUSED_OBJECT);
445eda14cbcSMatt Macy 			if (err == 0)
446eda14cbcSMatt Macy 				err = traverse_dnode(td, bp,
447eda14cbcSMatt Macy 				    &osp->os_groupused_dnode, zb->zb_objset,
448eda14cbcSMatt Macy 				    DMU_GROUPUSED_OBJECT);
449eda14cbcSMatt Macy 			if (err == 0)
450eda14cbcSMatt Macy 				err = traverse_dnode(td, bp,
451eda14cbcSMatt Macy 				    &osp->os_userused_dnode, zb->zb_objset,
452eda14cbcSMatt Macy 				    DMU_USERUSED_OBJECT);
453eda14cbcSMatt Macy 		}
454eda14cbcSMatt Macy 	}
455eda14cbcSMatt Macy 
456eda14cbcSMatt Macy 	if (buf)
457eda14cbcSMatt Macy 		arc_buf_destroy(buf, &buf);
458eda14cbcSMatt Macy 
459eda14cbcSMatt Macy post:
460eda14cbcSMatt Macy 	if (err == 0 && (td->td_flags & TRAVERSE_POST))
461eda14cbcSMatt Macy 		err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
462eda14cbcSMatt Macy 
463eda14cbcSMatt Macy 	if ((td->td_flags & TRAVERSE_HARD) && (err == EIO || err == ECKSUM)) {
464eda14cbcSMatt Macy 		/*
465eda14cbcSMatt Macy 		 * Ignore this disk error as requested by the HARD flag,
466eda14cbcSMatt Macy 		 * and continue traversal.
467eda14cbcSMatt Macy 		 */
468eda14cbcSMatt Macy 		err = 0;
469eda14cbcSMatt Macy 	}
470eda14cbcSMatt Macy 
471eda14cbcSMatt Macy 	/*
472eda14cbcSMatt Macy 	 * If we are stopping here, set td_resume.
473eda14cbcSMatt Macy 	 */
474eda14cbcSMatt Macy 	if (td->td_resume != NULL && err != 0 && !td->td_paused) {
475eda14cbcSMatt Macy 		td->td_resume->zb_objset = zb->zb_objset;
476eda14cbcSMatt Macy 		td->td_resume->zb_object = zb->zb_object;
477eda14cbcSMatt Macy 		td->td_resume->zb_level = 0;
478eda14cbcSMatt Macy 		/*
479eda14cbcSMatt Macy 		 * If we have stopped on an indirect block (e.g. due to
480eda14cbcSMatt Macy 		 * i/o error), we have not visited anything below it.
481eda14cbcSMatt Macy 		 * Set the bookmark to the first level-0 block that we need
482eda14cbcSMatt Macy 		 * to visit.  This way, the resuming code does not need to
483eda14cbcSMatt Macy 		 * deal with resuming from indirect blocks.
484eda14cbcSMatt Macy 		 *
485eda14cbcSMatt Macy 		 * Note, if zb_level <= 0, dnp may be NULL, so we don't want
486eda14cbcSMatt Macy 		 * to dereference it.
487eda14cbcSMatt Macy 		 */
488eda14cbcSMatt Macy 		td->td_resume->zb_blkid = zb->zb_blkid;
489eda14cbcSMatt Macy 		if (zb->zb_level > 0) {
490eda14cbcSMatt Macy 			td->td_resume->zb_blkid <<= zb->zb_level *
491eda14cbcSMatt Macy 			    (dnp->dn_indblkshift - SPA_BLKPTRSHIFT);
492eda14cbcSMatt Macy 		}
493eda14cbcSMatt Macy 		td->td_paused = B_TRUE;
494eda14cbcSMatt Macy 	}
495eda14cbcSMatt Macy 
496eda14cbcSMatt Macy 	return (err);
497eda14cbcSMatt Macy }
498eda14cbcSMatt Macy 
499eda14cbcSMatt Macy static void
500eda14cbcSMatt Macy prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *dnp,
501eda14cbcSMatt Macy     uint64_t objset, uint64_t object)
502eda14cbcSMatt Macy {
503eda14cbcSMatt Macy 	int j;
504eda14cbcSMatt Macy 	zbookmark_phys_t czb;
505eda14cbcSMatt Macy 
506eda14cbcSMatt Macy 	for (j = 0; j < dnp->dn_nblkptr; j++) {
507eda14cbcSMatt Macy 		SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
508eda14cbcSMatt Macy 		traverse_prefetch_metadata(td, &dnp->dn_blkptr[j], &czb);
509eda14cbcSMatt Macy 	}
510eda14cbcSMatt Macy 
511eda14cbcSMatt Macy 	if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
512eda14cbcSMatt Macy 		SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
513eda14cbcSMatt Macy 		traverse_prefetch_metadata(td, DN_SPILL_BLKPTR(dnp), &czb);
514eda14cbcSMatt Macy 	}
515eda14cbcSMatt Macy }
516eda14cbcSMatt Macy 
517eda14cbcSMatt Macy static int
518eda14cbcSMatt Macy traverse_dnode(traverse_data_t *td, const blkptr_t *bp, const dnode_phys_t *dnp,
519eda14cbcSMatt Macy     uint64_t objset, uint64_t object)
520eda14cbcSMatt Macy {
521eda14cbcSMatt Macy 	int j, err = 0;
522eda14cbcSMatt Macy 	zbookmark_phys_t czb;
523eda14cbcSMatt Macy 
524eda14cbcSMatt Macy 	if (object != DMU_META_DNODE_OBJECT && td->td_resume != NULL &&
525eda14cbcSMatt Macy 	    object < td->td_resume->zb_object)
526eda14cbcSMatt Macy 		return (0);
527eda14cbcSMatt Macy 
528eda14cbcSMatt Macy 	if (td->td_flags & TRAVERSE_PRE) {
529eda14cbcSMatt Macy 		SET_BOOKMARK(&czb, objset, object, ZB_DNODE_LEVEL,
530eda14cbcSMatt Macy 		    ZB_DNODE_BLKID);
531eda14cbcSMatt Macy 		err = td->td_func(td->td_spa, NULL, bp, &czb, dnp,
532eda14cbcSMatt Macy 		    td->td_arg);
533eda14cbcSMatt Macy 		if (err == TRAVERSE_VISIT_NO_CHILDREN)
534eda14cbcSMatt Macy 			return (0);
535eda14cbcSMatt Macy 		if (err != 0)
536eda14cbcSMatt Macy 			return (err);
537eda14cbcSMatt Macy 	}
538eda14cbcSMatt Macy 
539eda14cbcSMatt Macy 	for (j = 0; j < dnp->dn_nblkptr; j++) {
540eda14cbcSMatt Macy 		SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
541eda14cbcSMatt Macy 		err = traverse_visitbp(td, dnp, &dnp->dn_blkptr[j], &czb);
542eda14cbcSMatt Macy 		if (err != 0)
543eda14cbcSMatt Macy 			break;
544eda14cbcSMatt Macy 	}
545eda14cbcSMatt Macy 
546eda14cbcSMatt Macy 	if (err == 0 && (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) {
547eda14cbcSMatt Macy 		SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
548eda14cbcSMatt Macy 		err = traverse_visitbp(td, dnp, DN_SPILL_BLKPTR(dnp), &czb);
549eda14cbcSMatt Macy 	}
550eda14cbcSMatt Macy 
551eda14cbcSMatt Macy 	if (err == 0 && (td->td_flags & TRAVERSE_POST)) {
552eda14cbcSMatt Macy 		SET_BOOKMARK(&czb, objset, object, ZB_DNODE_LEVEL,
553eda14cbcSMatt Macy 		    ZB_DNODE_BLKID);
554eda14cbcSMatt Macy 		err = td->td_func(td->td_spa, NULL, bp, &czb, dnp,
555eda14cbcSMatt Macy 		    td->td_arg);
556eda14cbcSMatt Macy 		if (err == TRAVERSE_VISIT_NO_CHILDREN)
557eda14cbcSMatt Macy 			return (0);
558eda14cbcSMatt Macy 		if (err != 0)
559eda14cbcSMatt Macy 			return (err);
560eda14cbcSMatt Macy 	}
561eda14cbcSMatt Macy 	return (err);
562eda14cbcSMatt Macy }
563eda14cbcSMatt Macy 
564eda14cbcSMatt Macy static int
565eda14cbcSMatt Macy traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
566eda14cbcSMatt Macy     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
567eda14cbcSMatt Macy {
568e92ffd9bSMartin Matuska 	(void) zilog, (void) dnp;
569eda14cbcSMatt Macy 	prefetch_data_t *pfd = arg;
570eda14cbcSMatt Macy 	int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
571eda14cbcSMatt Macy 	arc_flags_t aflags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH |
572eda14cbcSMatt Macy 	    ARC_FLAG_PRESCIENT_PREFETCH;
573eda14cbcSMatt Macy 
574eda14cbcSMatt Macy 	ASSERT(pfd->pd_bytes_fetched >= 0);
575eda14cbcSMatt Macy 	if (zb->zb_level == ZB_DNODE_LEVEL)
576eda14cbcSMatt Macy 		return (0);
577eda14cbcSMatt Macy 	if (pfd->pd_cancel)
578eda14cbcSMatt Macy 		return (SET_ERROR(EINTR));
579eda14cbcSMatt Macy 
580eda14cbcSMatt Macy 	if (!prefetch_needed(pfd, bp))
581eda14cbcSMatt Macy 		return (0);
582eda14cbcSMatt Macy 
583eda14cbcSMatt Macy 	mutex_enter(&pfd->pd_mtx);
584eda14cbcSMatt Macy 	while (!pfd->pd_cancel && pfd->pd_bytes_fetched >= zfs_pd_bytes_max)
585eda14cbcSMatt Macy 		cv_wait_sig(&pfd->pd_cv, &pfd->pd_mtx);
586eda14cbcSMatt Macy 	pfd->pd_bytes_fetched += BP_GET_LSIZE(bp);
587eda14cbcSMatt Macy 	cv_broadcast(&pfd->pd_cv);
588eda14cbcSMatt Macy 	mutex_exit(&pfd->pd_mtx);
589eda14cbcSMatt Macy 
590eda14cbcSMatt Macy 	if ((pfd->pd_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
591eda14cbcSMatt Macy 		zio_flags |= ZIO_FLAG_RAW;
592eda14cbcSMatt Macy 
593eda14cbcSMatt Macy 	(void) arc_read(NULL, spa, bp, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
594eda14cbcSMatt Macy 	    zio_flags, &aflags, zb);
595eda14cbcSMatt Macy 
596eda14cbcSMatt Macy 	return (0);
597eda14cbcSMatt Macy }
598eda14cbcSMatt Macy 
599eda14cbcSMatt Macy static void
600eda14cbcSMatt Macy traverse_prefetch_thread(void *arg)
601eda14cbcSMatt Macy {
602eda14cbcSMatt Macy 	traverse_data_t *td_main = arg;
603eda14cbcSMatt Macy 	traverse_data_t td = *td_main;
604eda14cbcSMatt Macy 	zbookmark_phys_t czb;
605eda14cbcSMatt Macy 	fstrans_cookie_t cookie = spl_fstrans_mark();
606eda14cbcSMatt Macy 
607eda14cbcSMatt Macy 	td.td_func = traverse_prefetcher;
608eda14cbcSMatt Macy 	td.td_arg = td_main->td_pfd;
609eda14cbcSMatt Macy 	td.td_pfd = NULL;
610eda14cbcSMatt Macy 	td.td_resume = &td_main->td_pfd->pd_resume;
611eda14cbcSMatt Macy 
612eda14cbcSMatt Macy 	SET_BOOKMARK(&czb, td.td_objset,
613eda14cbcSMatt Macy 	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
614eda14cbcSMatt Macy 	(void) traverse_visitbp(&td, NULL, td.td_rootbp, &czb);
615eda14cbcSMatt Macy 
616eda14cbcSMatt Macy 	mutex_enter(&td_main->td_pfd->pd_mtx);
617eda14cbcSMatt Macy 	td_main->td_pfd->pd_exited = B_TRUE;
618eda14cbcSMatt Macy 	cv_broadcast(&td_main->td_pfd->pd_cv);
619eda14cbcSMatt Macy 	mutex_exit(&td_main->td_pfd->pd_mtx);
620eda14cbcSMatt Macy 	spl_fstrans_unmark(cookie);
621eda14cbcSMatt Macy }
622eda14cbcSMatt Macy 
623eda14cbcSMatt Macy /*
624eda14cbcSMatt Macy  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
625eda14cbcSMatt Macy  * in syncing context).
626eda14cbcSMatt Macy  */
627eda14cbcSMatt Macy static int
628eda14cbcSMatt Macy traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
629eda14cbcSMatt Macy     uint64_t txg_start, zbookmark_phys_t *resume, int flags,
630eda14cbcSMatt Macy     blkptr_cb_t func, void *arg)
631eda14cbcSMatt Macy {
632eda14cbcSMatt Macy 	traverse_data_t *td;
633eda14cbcSMatt Macy 	prefetch_data_t *pd;
634eda14cbcSMatt Macy 	zbookmark_phys_t *czb;
635eda14cbcSMatt Macy 	int err;
636eda14cbcSMatt Macy 
637eda14cbcSMatt Macy 	ASSERT(ds == NULL || objset == ds->ds_object);
638eda14cbcSMatt Macy 	ASSERT(!(flags & TRAVERSE_PRE) || !(flags & TRAVERSE_POST));
639eda14cbcSMatt Macy 
640eda14cbcSMatt Macy 	td = kmem_alloc(sizeof (traverse_data_t), KM_SLEEP);
641eda14cbcSMatt Macy 	pd = kmem_zalloc(sizeof (prefetch_data_t), KM_SLEEP);
642eda14cbcSMatt Macy 	czb = kmem_alloc(sizeof (zbookmark_phys_t), KM_SLEEP);
643eda14cbcSMatt Macy 
644eda14cbcSMatt Macy 	td->td_spa = spa;
645eda14cbcSMatt Macy 	td->td_objset = objset;
646eda14cbcSMatt Macy 	td->td_rootbp = rootbp;
647eda14cbcSMatt Macy 	td->td_min_txg = txg_start;
648eda14cbcSMatt Macy 	td->td_resume = resume;
649eda14cbcSMatt Macy 	td->td_func = func;
650eda14cbcSMatt Macy 	td->td_arg = arg;
651eda14cbcSMatt Macy 	td->td_pfd = pd;
652eda14cbcSMatt Macy 	td->td_flags = flags;
653eda14cbcSMatt Macy 	td->td_paused = B_FALSE;
654eda14cbcSMatt Macy 	td->td_realloc_possible = (txg_start == 0 ? B_FALSE : B_TRUE);
655eda14cbcSMatt Macy 
656eda14cbcSMatt Macy 	if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
657eda14cbcSMatt Macy 		VERIFY(spa_feature_enabled_txg(spa,
658eda14cbcSMatt Macy 		    SPA_FEATURE_HOLE_BIRTH, &td->td_hole_birth_enabled_txg));
659eda14cbcSMatt Macy 	} else {
660eda14cbcSMatt Macy 		td->td_hole_birth_enabled_txg = UINT64_MAX;
661eda14cbcSMatt Macy 	}
662eda14cbcSMatt Macy 
663eda14cbcSMatt Macy 	pd->pd_flags = flags;
664eda14cbcSMatt Macy 	if (resume != NULL)
665eda14cbcSMatt Macy 		pd->pd_resume = *resume;
666eda14cbcSMatt Macy 	mutex_init(&pd->pd_mtx, NULL, MUTEX_DEFAULT, NULL);
667eda14cbcSMatt Macy 	cv_init(&pd->pd_cv, NULL, CV_DEFAULT, NULL);
668eda14cbcSMatt Macy 
669eda14cbcSMatt Macy 	SET_BOOKMARK(czb, td->td_objset,
670eda14cbcSMatt Macy 	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
671eda14cbcSMatt Macy 
672eda14cbcSMatt Macy 	/* See comment on ZIL traversal in dsl_scan_visitds. */
673eda14cbcSMatt Macy 	if (ds != NULL && !ds->ds_is_snapshot && !BP_IS_HOLE(rootbp)) {
674*dbd5678dSMartin Matuska 		zio_flag_t zio_flags = ZIO_FLAG_CANFAIL;
675eda14cbcSMatt Macy 		uint32_t flags = ARC_FLAG_WAIT;
676eda14cbcSMatt Macy 		objset_phys_t *osp;
677eda14cbcSMatt Macy 		arc_buf_t *buf;
678eda14cbcSMatt Macy 		ASSERT(!BP_IS_REDACTED(rootbp));
679eda14cbcSMatt Macy 
680eda14cbcSMatt Macy 		if ((td->td_flags & TRAVERSE_NO_DECRYPT) &&
681eda14cbcSMatt Macy 		    BP_IS_PROTECTED(rootbp))
682eda14cbcSMatt Macy 			zio_flags |= ZIO_FLAG_RAW;
683eda14cbcSMatt Macy 
684eda14cbcSMatt Macy 		err = arc_read(NULL, td->td_spa, rootbp, arc_getbuf_func,
685eda14cbcSMatt Macy 		    &buf, ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, czb);
686eda14cbcSMatt Macy 		if (err != 0) {
687eda14cbcSMatt Macy 			/*
688eda14cbcSMatt Macy 			 * If both TRAVERSE_HARD and TRAVERSE_PRE are set,
689eda14cbcSMatt Macy 			 * continue to visitbp so that td_func can be called
690eda14cbcSMatt Macy 			 * in pre stage, and err will reset to zero.
691eda14cbcSMatt Macy 			 */
692eda14cbcSMatt Macy 			if (!(td->td_flags & TRAVERSE_HARD) ||
693eda14cbcSMatt Macy 			    !(td->td_flags & TRAVERSE_PRE))
694eda14cbcSMatt Macy 				goto out;
695eda14cbcSMatt Macy 		} else {
696eda14cbcSMatt Macy 			osp = buf->b_data;
697eda14cbcSMatt Macy 			traverse_zil(td, &osp->os_zil_header);
698eda14cbcSMatt Macy 			arc_buf_destroy(buf, &buf);
699eda14cbcSMatt Macy 		}
700eda14cbcSMatt Macy 	}
701eda14cbcSMatt Macy 
702eda14cbcSMatt Macy 	if (!(flags & TRAVERSE_PREFETCH_DATA) ||
703eda14cbcSMatt Macy 	    taskq_dispatch(spa->spa_prefetch_taskq, traverse_prefetch_thread,
704eda14cbcSMatt Macy 	    td, TQ_NOQUEUE) == TASKQID_INVALID)
705eda14cbcSMatt Macy 		pd->pd_exited = B_TRUE;
706eda14cbcSMatt Macy 
707eda14cbcSMatt Macy 	err = traverse_visitbp(td, NULL, rootbp, czb);
708eda14cbcSMatt Macy 
709eda14cbcSMatt Macy 	mutex_enter(&pd->pd_mtx);
710eda14cbcSMatt Macy 	pd->pd_cancel = B_TRUE;
711eda14cbcSMatt Macy 	cv_broadcast(&pd->pd_cv);
712eda14cbcSMatt Macy 	while (!pd->pd_exited)
713eda14cbcSMatt Macy 		cv_wait_sig(&pd->pd_cv, &pd->pd_mtx);
714eda14cbcSMatt Macy 	mutex_exit(&pd->pd_mtx);
715eda14cbcSMatt Macy out:
716eda14cbcSMatt Macy 	mutex_destroy(&pd->pd_mtx);
717eda14cbcSMatt Macy 	cv_destroy(&pd->pd_cv);
718eda14cbcSMatt Macy 
719eda14cbcSMatt Macy 	kmem_free(czb, sizeof (zbookmark_phys_t));
720eda14cbcSMatt Macy 	kmem_free(pd, sizeof (struct prefetch_data));
721eda14cbcSMatt Macy 	kmem_free(td, sizeof (struct traverse_data));
722eda14cbcSMatt Macy 
723eda14cbcSMatt Macy 	return (err);
724eda14cbcSMatt Macy }
725eda14cbcSMatt Macy 
726eda14cbcSMatt Macy /*
727eda14cbcSMatt Macy  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
728eda14cbcSMatt Macy  * in syncing context).
729eda14cbcSMatt Macy  */
730eda14cbcSMatt Macy int
731eda14cbcSMatt Macy traverse_dataset_resume(dsl_dataset_t *ds, uint64_t txg_start,
732eda14cbcSMatt Macy     zbookmark_phys_t *resume,
733eda14cbcSMatt Macy     int flags, blkptr_cb_t func, void *arg)
734eda14cbcSMatt Macy {
735eda14cbcSMatt Macy 	return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds, ds->ds_object,
736eda14cbcSMatt Macy 	    &dsl_dataset_phys(ds)->ds_bp, txg_start, resume, flags, func, arg));
737eda14cbcSMatt Macy }
738eda14cbcSMatt Macy 
739eda14cbcSMatt Macy int
740eda14cbcSMatt Macy traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start,
741eda14cbcSMatt Macy     int flags, blkptr_cb_t func, void *arg)
742eda14cbcSMatt Macy {
743eda14cbcSMatt Macy 	return (traverse_dataset_resume(ds, txg_start, NULL, flags, func, arg));
744eda14cbcSMatt Macy }
745eda14cbcSMatt Macy 
746eda14cbcSMatt Macy int
747eda14cbcSMatt Macy traverse_dataset_destroyed(spa_t *spa, blkptr_t *blkptr,
748eda14cbcSMatt Macy     uint64_t txg_start, zbookmark_phys_t *resume, int flags,
749eda14cbcSMatt Macy     blkptr_cb_t func, void *arg)
750eda14cbcSMatt Macy {
751eda14cbcSMatt Macy 	return (traverse_impl(spa, NULL, ZB_DESTROYED_OBJSET,
752eda14cbcSMatt Macy 	    blkptr, txg_start, resume, flags, func, arg));
753eda14cbcSMatt Macy }
754eda14cbcSMatt Macy 
755eda14cbcSMatt Macy /*
756eda14cbcSMatt Macy  * NB: pool must not be changing on-disk (eg, from zdb or sync context).
757eda14cbcSMatt Macy  */
758eda14cbcSMatt Macy int
759eda14cbcSMatt Macy traverse_pool(spa_t *spa, uint64_t txg_start, int flags,
760eda14cbcSMatt Macy     blkptr_cb_t func, void *arg)
761eda14cbcSMatt Macy {
762eda14cbcSMatt Macy 	int err;
763eda14cbcSMatt Macy 	dsl_pool_t *dp = spa_get_dsl(spa);
764eda14cbcSMatt Macy 	objset_t *mos = dp->dp_meta_objset;
765eda14cbcSMatt Macy 	boolean_t hard = (flags & TRAVERSE_HARD);
766eda14cbcSMatt Macy 
767eda14cbcSMatt Macy 	/* visit the MOS */
768eda14cbcSMatt Macy 	err = traverse_impl(spa, NULL, 0, spa_get_rootblkptr(spa),
769eda14cbcSMatt Macy 	    txg_start, NULL, flags, func, arg);
770eda14cbcSMatt Macy 	if (err != 0)
771eda14cbcSMatt Macy 		return (err);
772eda14cbcSMatt Macy 
773eda14cbcSMatt Macy 	/* visit each dataset */
774eda14cbcSMatt Macy 	for (uint64_t obj = 1; err == 0;
775eda14cbcSMatt Macy 	    err = dmu_object_next(mos, &obj, B_FALSE, txg_start)) {
776eda14cbcSMatt Macy 		dmu_object_info_t doi;
777eda14cbcSMatt Macy 
778eda14cbcSMatt Macy 		err = dmu_object_info(mos, obj, &doi);
779eda14cbcSMatt Macy 		if (err != 0) {
780eda14cbcSMatt Macy 			if (hard)
781eda14cbcSMatt Macy 				continue;
782eda14cbcSMatt Macy 			break;
783eda14cbcSMatt Macy 		}
784eda14cbcSMatt Macy 
785eda14cbcSMatt Macy 		if (doi.doi_bonus_type == DMU_OT_DSL_DATASET) {
786eda14cbcSMatt Macy 			dsl_dataset_t *ds;
787eda14cbcSMatt Macy 			uint64_t txg = txg_start;
788eda14cbcSMatt Macy 
789eda14cbcSMatt Macy 			dsl_pool_config_enter(dp, FTAG);
790eda14cbcSMatt Macy 			err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
791eda14cbcSMatt Macy 			dsl_pool_config_exit(dp, FTAG);
792eda14cbcSMatt Macy 			if (err != 0) {
793eda14cbcSMatt Macy 				if (hard)
794eda14cbcSMatt Macy 					continue;
795eda14cbcSMatt Macy 				break;
796eda14cbcSMatt Macy 			}
797eda14cbcSMatt Macy 			if (dsl_dataset_phys(ds)->ds_prev_snap_txg > txg)
798eda14cbcSMatt Macy 				txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
799eda14cbcSMatt Macy 			err = traverse_dataset(ds, txg, flags, func, arg);
800eda14cbcSMatt Macy 			dsl_dataset_rele(ds, FTAG);
801eda14cbcSMatt Macy 			if (err != 0)
802eda14cbcSMatt Macy 				break;
803eda14cbcSMatt Macy 		}
804eda14cbcSMatt Macy 	}
805eda14cbcSMatt Macy 	if (err == ESRCH)
806eda14cbcSMatt Macy 		err = 0;
807eda14cbcSMatt Macy 	return (err);
808eda14cbcSMatt Macy }
809eda14cbcSMatt Macy 
810eda14cbcSMatt Macy EXPORT_SYMBOL(traverse_dataset);
811eda14cbcSMatt Macy EXPORT_SYMBOL(traverse_pool);
812eda14cbcSMatt Macy 
813eda14cbcSMatt Macy ZFS_MODULE_PARAM(zfs, zfs_, pd_bytes_max, INT, ZMOD_RW,
814eda14cbcSMatt Macy 	"Max number of bytes to prefetch");
815eda14cbcSMatt Macy 
816be181ee2SMartin Matuska ZFS_MODULE_PARAM(zfs, zfs_, traverse_indirect_prefetch_limit, UINT, ZMOD_RW,
81716038816SMartin Matuska 	"Traverse prefetch number of blocks pointed by indirect block");
81816038816SMartin Matuska 
819eda14cbcSMatt Macy #if defined(_KERNEL)
820eda14cbcSMatt Macy module_param_named(ignore_hole_birth, send_holes_without_birth_time, int, 0644);
821eda14cbcSMatt Macy MODULE_PARM_DESC(ignore_hole_birth,
822eda14cbcSMatt Macy 	"Alias for send_holes_without_birth_time");
823eda14cbcSMatt Macy #endif
824eda14cbcSMatt Macy 
825c03c5b1cSMartin Matuska /* CSTYLED */
826eda14cbcSMatt Macy ZFS_MODULE_PARAM(zfs, , send_holes_without_birth_time, INT, ZMOD_RW,
827eda14cbcSMatt Macy 	"Ignore hole_birth txg for zfs send");
828