xref: /titanic_41/usr/src/uts/common/fs/zfs/zil.c (revision 675fc291908baceb17f92b0b6d961439aaddafc9)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
24  */
25 
26 /* Portions Copyright 2010 Robert Milkowski */
27 
28 #include <sys/zfs_context.h>
29 #include <sys/spa.h>
30 #include <sys/dmu.h>
31 #include <sys/zap.h>
32 #include <sys/arc.h>
33 #include <sys/stat.h>
34 #include <sys/resource.h>
35 #include <sys/zil.h>
36 #include <sys/zil_impl.h>
37 #include <sys/dsl_dataset.h>
38 #include <sys/vdev_impl.h>
39 #include <sys/dmu_tx.h>
40 #include <sys/dsl_pool.h>
41 
42 /*
43  * The zfs intent log (ZIL) saves transaction records of system calls
44  * that change the file system in memory with enough information
45  * to be able to replay them. These are stored in memory until
46  * either the DMU transaction group (txg) commits them to the stable pool
47  * and they can be discarded, or they are flushed to the stable log
48  * (also in the pool) due to a fsync, O_DSYNC or other synchronous
49  * requirement. In the event of a panic or power fail then those log
50  * records (transactions) are replayed.
51  *
52  * There is one ZIL per file system. Its on-disk (pool) format consists
53  * of 3 parts:
54  *
55  * 	- ZIL header
56  * 	- ZIL blocks
57  * 	- ZIL records
58  *
59  * A log record holds a system call transaction. Log blocks can
60  * hold many log records and the blocks are chained together.
61  * Each ZIL block contains a block pointer (blkptr_t) to the next
62  * ZIL block in the chain. The ZIL header points to the first
63  * block in the chain. Note there is not a fixed place in the pool
64  * to hold blocks. They are dynamically allocated and freed as
65  * needed from the blocks available. Figure X shows the ZIL structure:
66  */
67 
68 /*
69  * Disable intent logging replay.  This global ZIL switch affects all pools.
70  */
71 int zil_replay_disable = 0;
72 
73 /*
74  * Tunable parameter for debugging or performance analysis.  Setting
75  * zfs_nocacheflush will cause corruption on power loss if a volatile
76  * out-of-order write cache is enabled.
77  */
78 boolean_t zfs_nocacheflush = B_FALSE;
79 
80 static kmem_cache_t *zil_lwb_cache;
81 
82 static void zil_async_to_sync(zilog_t *zilog, uint64_t foid);
83 
84 #define	LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
85     sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
86 
87 
88 /*
89  * ziltest is by and large an ugly hack, but very useful in
90  * checking replay without tedious work.
91  * When running ziltest we want to keep all itx's and so maintain
92  * a single list in the zl_itxg[] that uses a high txg: ZILTEST_TXG
93  * We subtract TXG_CONCURRENT_STATES to allow for common code.
94  */
95 #define	ZILTEST_TXG (UINT64_MAX - TXG_CONCURRENT_STATES)
96 
97 static int
zil_bp_compare(const void * x1,const void * x2)98 zil_bp_compare(const void *x1, const void *x2)
99 {
100 	const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva;
101 	const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva;
102 
103 	if (DVA_GET_VDEV(dva1) < DVA_GET_VDEV(dva2))
104 		return (-1);
105 	if (DVA_GET_VDEV(dva1) > DVA_GET_VDEV(dva2))
106 		return (1);
107 
108 	if (DVA_GET_OFFSET(dva1) < DVA_GET_OFFSET(dva2))
109 		return (-1);
110 	if (DVA_GET_OFFSET(dva1) > DVA_GET_OFFSET(dva2))
111 		return (1);
112 
113 	return (0);
114 }
115 
116 static void
zil_bp_tree_init(zilog_t * zilog)117 zil_bp_tree_init(zilog_t *zilog)
118 {
119 	avl_create(&zilog->zl_bp_tree, zil_bp_compare,
120 	    sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node));
121 }
122 
123 static void
zil_bp_tree_fini(zilog_t * zilog)124 zil_bp_tree_fini(zilog_t *zilog)
125 {
126 	avl_tree_t *t = &zilog->zl_bp_tree;
127 	zil_bp_node_t *zn;
128 	void *cookie = NULL;
129 
130 	while ((zn = avl_destroy_nodes(t, &cookie)) != NULL)
131 		kmem_free(zn, sizeof (zil_bp_node_t));
132 
133 	avl_destroy(t);
134 }
135 
136 int
zil_bp_tree_add(zilog_t * zilog,const blkptr_t * bp)137 zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp)
138 {
139 	avl_tree_t *t = &zilog->zl_bp_tree;
140 	const dva_t *dva;
141 	zil_bp_node_t *zn;
142 	avl_index_t where;
143 
144 	if (BP_IS_EMBEDDED(bp))
145 		return (0);
146 
147 	dva = BP_IDENTITY(bp);
148 
149 	if (avl_find(t, dva, &where) != NULL)
150 		return (SET_ERROR(EEXIST));
151 
152 	zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP);
153 	zn->zn_dva = *dva;
154 	avl_insert(t, zn, where);
155 
156 	return (0);
157 }
158 
159 static zil_header_t *
zil_header_in_syncing_context(zilog_t * zilog)160 zil_header_in_syncing_context(zilog_t *zilog)
161 {
162 	return ((zil_header_t *)zilog->zl_header);
163 }
164 
165 static void
zil_init_log_chain(zilog_t * zilog,blkptr_t * bp)166 zil_init_log_chain(zilog_t *zilog, blkptr_t *bp)
167 {
168 	zio_cksum_t *zc = &bp->blk_cksum;
169 
170 	zc->zc_word[ZIL_ZC_GUID_0] = spa_get_random(-1ULL);
171 	zc->zc_word[ZIL_ZC_GUID_1] = spa_get_random(-1ULL);
172 	zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os);
173 	zc->zc_word[ZIL_ZC_SEQ] = 1ULL;
174 }
175 
176 /*
177  * Read a log block and make sure it's valid.
178  */
179 static int
zil_read_log_block(zilog_t * zilog,const blkptr_t * bp,blkptr_t * nbp,void * dst,char ** end)180 zil_read_log_block(zilog_t *zilog, const blkptr_t *bp, blkptr_t *nbp, void *dst,
181     char **end)
182 {
183 	enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
184 	arc_flags_t aflags = ARC_FLAG_WAIT;
185 	arc_buf_t *abuf = NULL;
186 	zbookmark_phys_t zb;
187 	int error;
188 
189 	if (zilog->zl_header->zh_claim_txg == 0)
190 		zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
191 
192 	if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
193 		zio_flags |= ZIO_FLAG_SPECULATIVE;
194 
195 	SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET],
196 	    ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
197 
198 	error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
199 	    ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
200 
201 	if (error == 0) {
202 		zio_cksum_t cksum = bp->blk_cksum;
203 
204 		/*
205 		 * Validate the checksummed log block.
206 		 *
207 		 * Sequence numbers should be... sequential.  The checksum
208 		 * verifier for the next block should be bp's checksum plus 1.
209 		 *
210 		 * Also check the log chain linkage and size used.
211 		 */
212 		cksum.zc_word[ZIL_ZC_SEQ]++;
213 
214 		if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
215 			zil_chain_t *zilc = abuf->b_data;
216 			char *lr = (char *)(zilc + 1);
217 			uint64_t len = zilc->zc_nused - sizeof (zil_chain_t);
218 
219 			if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
220 			    sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) {
221 				error = SET_ERROR(ECKSUM);
222 			} else {
223 				ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE);
224 				bcopy(lr, dst, len);
225 				*end = (char *)dst + len;
226 				*nbp = zilc->zc_next_blk;
227 			}
228 		} else {
229 			char *lr = abuf->b_data;
230 			uint64_t size = BP_GET_LSIZE(bp);
231 			zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1;
232 
233 			if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
234 			    sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) ||
235 			    (zilc->zc_nused > (size - sizeof (*zilc)))) {
236 				error = SET_ERROR(ECKSUM);
237 			} else {
238 				ASSERT3U(zilc->zc_nused, <=,
239 				    SPA_OLD_MAXBLOCKSIZE);
240 				bcopy(lr, dst, zilc->zc_nused);
241 				*end = (char *)dst + zilc->zc_nused;
242 				*nbp = zilc->zc_next_blk;
243 			}
244 		}
245 
246 		VERIFY(arc_buf_remove_ref(abuf, &abuf));
247 	}
248 
249 	return (error);
250 }
251 
252 /*
253  * Read a TX_WRITE log data block.
254  */
255 static int
zil_read_log_data(zilog_t * zilog,const lr_write_t * lr,void * wbuf)256 zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf)
257 {
258 	enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
259 	const blkptr_t *bp = &lr->lr_blkptr;
260 	arc_flags_t aflags = ARC_FLAG_WAIT;
261 	arc_buf_t *abuf = NULL;
262 	zbookmark_phys_t zb;
263 	int error;
264 
265 	if (BP_IS_HOLE(bp)) {
266 		if (wbuf != NULL)
267 			bzero(wbuf, MAX(BP_GET_LSIZE(bp), lr->lr_length));
268 		return (0);
269 	}
270 
271 	if (zilog->zl_header->zh_claim_txg == 0)
272 		zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
273 
274 	SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid,
275 	    ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
276 
277 	error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
278 	    ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
279 
280 	if (error == 0) {
281 		if (wbuf != NULL)
282 			bcopy(abuf->b_data, wbuf, arc_buf_size(abuf));
283 		(void) arc_buf_remove_ref(abuf, &abuf);
284 	}
285 
286 	return (error);
287 }
288 
289 /*
290  * Parse the intent log, and call parse_func for each valid record within.
291  */
292 int
zil_parse(zilog_t * zilog,zil_parse_blk_func_t * parse_blk_func,zil_parse_lr_func_t * parse_lr_func,void * arg,uint64_t txg)293 zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
294     zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg)
295 {
296 	const zil_header_t *zh = zilog->zl_header;
297 	boolean_t claimed = !!zh->zh_claim_txg;
298 	uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX;
299 	uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX;
300 	uint64_t max_blk_seq = 0;
301 	uint64_t max_lr_seq = 0;
302 	uint64_t blk_count = 0;
303 	uint64_t lr_count = 0;
304 	blkptr_t blk, next_blk;
305 	char *lrbuf, *lrp;
306 	int error = 0;
307 
308 	/*
309 	 * Old logs didn't record the maximum zh_claim_lr_seq.
310 	 */
311 	if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
312 		claim_lr_seq = UINT64_MAX;
313 
314 	/*
315 	 * Starting at the block pointed to by zh_log we read the log chain.
316 	 * For each block in the chain we strongly check that block to
317 	 * ensure its validity.  We stop when an invalid block is found.
318 	 * For each block pointer in the chain we call parse_blk_func().
319 	 * For each record in each valid block we call parse_lr_func().
320 	 * If the log has been claimed, stop if we encounter a sequence
321 	 * number greater than the highest claimed sequence number.
322 	 */
323 	lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE);
324 	zil_bp_tree_init(zilog);
325 
326 	for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) {
327 		uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ];
328 		int reclen;
329 		char *end;
330 
331 		if (blk_seq > claim_blk_seq)
332 			break;
333 		if ((error = parse_blk_func(zilog, &blk, arg, txg)) != 0)
334 			break;
335 		ASSERT3U(max_blk_seq, <, blk_seq);
336 		max_blk_seq = blk_seq;
337 		blk_count++;
338 
339 		if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq)
340 			break;
341 
342 		error = zil_read_log_block(zilog, &blk, &next_blk, lrbuf, &end);
343 		if (error != 0)
344 			break;
345 
346 		for (lrp = lrbuf; lrp < end; lrp += reclen) {
347 			lr_t *lr = (lr_t *)lrp;
348 			reclen = lr->lrc_reclen;
349 			ASSERT3U(reclen, >=, sizeof (lr_t));
350 			if (lr->lrc_seq > claim_lr_seq)
351 				goto done;
352 			if ((error = parse_lr_func(zilog, lr, arg, txg)) != 0)
353 				goto done;
354 			ASSERT3U(max_lr_seq, <, lr->lrc_seq);
355 			max_lr_seq = lr->lrc_seq;
356 			lr_count++;
357 		}
358 	}
359 done:
360 	zilog->zl_parse_error = error;
361 	zilog->zl_parse_blk_seq = max_blk_seq;
362 	zilog->zl_parse_lr_seq = max_lr_seq;
363 	zilog->zl_parse_blk_count = blk_count;
364 	zilog->zl_parse_lr_count = lr_count;
365 
366 	ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) ||
367 	    (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq));
368 
369 	zil_bp_tree_fini(zilog);
370 	zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE);
371 
372 	return (error);
373 }
374 
375 static int
zil_claim_log_block(zilog_t * zilog,blkptr_t * bp,void * tx,uint64_t first_txg)376 zil_claim_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg)
377 {
378 	/*
379 	 * Claim log block if not already committed and not already claimed.
380 	 * If tx == NULL, just verify that the block is claimable.
381 	 */
382 	if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg ||
383 	    zil_bp_tree_add(zilog, bp) != 0)
384 		return (0);
385 
386 	return (zio_wait(zio_claim(NULL, zilog->zl_spa,
387 	    tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL,
388 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB)));
389 }
390 
391 static int
zil_claim_log_record(zilog_t * zilog,lr_t * lrc,void * tx,uint64_t first_txg)392 zil_claim_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg)
393 {
394 	lr_write_t *lr = (lr_write_t *)lrc;
395 	int error;
396 
397 	if (lrc->lrc_txtype != TX_WRITE)
398 		return (0);
399 
400 	/*
401 	 * If the block is not readable, don't claim it.  This can happen
402 	 * in normal operation when a log block is written to disk before
403 	 * some of the dmu_sync() blocks it points to.  In this case, the
404 	 * transaction cannot have been committed to anyone (we would have
405 	 * waited for all writes to be stable first), so it is semantically
406 	 * correct to declare this the end of the log.
407 	 */
408 	if (lr->lr_blkptr.blk_birth >= first_txg &&
409 	    (error = zil_read_log_data(zilog, lr, NULL)) != 0)
410 		return (error);
411 	return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg));
412 }
413 
414 /* ARGSUSED */
415 static int
zil_free_log_block(zilog_t * zilog,blkptr_t * bp,void * tx,uint64_t claim_txg)416 zil_free_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t claim_txg)
417 {
418 	zio_free_zil(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
419 
420 	return (0);
421 }
422 
423 static int
zil_free_log_record(zilog_t * zilog,lr_t * lrc,void * tx,uint64_t claim_txg)424 zil_free_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t claim_txg)
425 {
426 	lr_write_t *lr = (lr_write_t *)lrc;
427 	blkptr_t *bp = &lr->lr_blkptr;
428 
429 	/*
430 	 * If we previously claimed it, we need to free it.
431 	 */
432 	if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE &&
433 	    bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 &&
434 	    !BP_IS_HOLE(bp))
435 		zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
436 
437 	return (0);
438 }
439 
440 static lwb_t *
zil_alloc_lwb(zilog_t * zilog,blkptr_t * bp,uint64_t txg)441 zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, uint64_t txg)
442 {
443 	lwb_t *lwb;
444 
445 	lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP);
446 	lwb->lwb_zilog = zilog;
447 	lwb->lwb_blk = *bp;
448 	lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp));
449 	lwb->lwb_max_txg = txg;
450 	lwb->lwb_zio = NULL;
451 	lwb->lwb_tx = NULL;
452 	if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
453 		lwb->lwb_nused = sizeof (zil_chain_t);
454 		lwb->lwb_sz = BP_GET_LSIZE(bp);
455 	} else {
456 		lwb->lwb_nused = 0;
457 		lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t);
458 	}
459 
460 	mutex_enter(&zilog->zl_lock);
461 	list_insert_tail(&zilog->zl_lwb_list, lwb);
462 	mutex_exit(&zilog->zl_lock);
463 
464 	return (lwb);
465 }
466 
467 /*
468  * Called when we create in-memory log transactions so that we know
469  * to cleanup the itxs at the end of spa_sync().
470  */
471 void
zilog_dirty(zilog_t * zilog,uint64_t txg)472 zilog_dirty(zilog_t *zilog, uint64_t txg)
473 {
474 	dsl_pool_t *dp = zilog->zl_dmu_pool;
475 	dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
476 
477 	if (ds->ds_is_snapshot)
478 		panic("dirtying snapshot!");
479 
480 	if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) {
481 		/* up the hold count until we can be written out */
482 		dmu_buf_add_ref(ds->ds_dbuf, zilog);
483 	}
484 }
485 
486 boolean_t
zilog_is_dirty(zilog_t * zilog)487 zilog_is_dirty(zilog_t *zilog)
488 {
489 	dsl_pool_t *dp = zilog->zl_dmu_pool;
490 
491 	for (int t = 0; t < TXG_SIZE; t++) {
492 		if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t))
493 			return (B_TRUE);
494 	}
495 	return (B_FALSE);
496 }
497 
498 /*
499  * Create an on-disk intent log.
500  */
501 static lwb_t *
zil_create(zilog_t * zilog)502 zil_create(zilog_t *zilog)
503 {
504 	const zil_header_t *zh = zilog->zl_header;
505 	lwb_t *lwb = NULL;
506 	uint64_t txg = 0;
507 	dmu_tx_t *tx = NULL;
508 	blkptr_t blk;
509 	int error = 0;
510 
511 	/*
512 	 * Wait for any previous destroy to complete.
513 	 */
514 	txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
515 
516 	ASSERT(zh->zh_claim_txg == 0);
517 	ASSERT(zh->zh_replay_seq == 0);
518 
519 	blk = zh->zh_log;
520 
521 	/*
522 	 * Allocate an initial log block if:
523 	 *    - there isn't one already
524 	 *    - the existing block is the wrong endianess
525 	 */
526 	if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) {
527 		tx = dmu_tx_create(zilog->zl_os);
528 		VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
529 		dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
530 		txg = dmu_tx_get_txg(tx);
531 
532 		if (!BP_IS_HOLE(&blk)) {
533 			zio_free_zil(zilog->zl_spa, txg, &blk);
534 			BP_ZERO(&blk);
535 		}
536 
537 		error = zio_alloc_zil(zilog->zl_spa, txg, &blk, NULL,
538 		    ZIL_MIN_BLKSZ, zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);
539 
540 		if (error == 0)
541 			zil_init_log_chain(zilog, &blk);
542 	}
543 
544 	/*
545 	 * Allocate a log write buffer (lwb) for the first log block.
546 	 */
547 	if (error == 0)
548 		lwb = zil_alloc_lwb(zilog, &blk, txg);
549 
550 	/*
551 	 * If we just allocated the first log block, commit our transaction
552 	 * and wait for zil_sync() to stuff the block poiner into zh_log.
553 	 * (zh is part of the MOS, so we cannot modify it in open context.)
554 	 */
555 	if (tx != NULL) {
556 		dmu_tx_commit(tx);
557 		txg_wait_synced(zilog->zl_dmu_pool, txg);
558 	}
559 
560 	ASSERT(bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
561 
562 	return (lwb);
563 }
564 
565 /*
566  * In one tx, free all log blocks and clear the log header.
567  * If keep_first is set, then we're replaying a log with no content.
568  * We want to keep the first block, however, so that the first
569  * synchronous transaction doesn't require a txg_wait_synced()
570  * in zil_create().  We don't need to txg_wait_synced() here either
571  * when keep_first is set, because both zil_create() and zil_destroy()
572  * will wait for any in-progress destroys to complete.
573  */
574 void
zil_destroy(zilog_t * zilog,boolean_t keep_first)575 zil_destroy(zilog_t *zilog, boolean_t keep_first)
576 {
577 	const zil_header_t *zh = zilog->zl_header;
578 	lwb_t *lwb;
579 	dmu_tx_t *tx;
580 	uint64_t txg;
581 
582 	/*
583 	 * Wait for any previous destroy to complete.
584 	 */
585 	txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
586 
587 	zilog->zl_old_header = *zh;		/* debugging aid */
588 
589 	if (BP_IS_HOLE(&zh->zh_log))
590 		return;
591 
592 	tx = dmu_tx_create(zilog->zl_os);
593 	VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
594 	dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
595 	txg = dmu_tx_get_txg(tx);
596 
597 	mutex_enter(&zilog->zl_lock);
598 
599 	ASSERT3U(zilog->zl_destroy_txg, <, txg);
600 	zilog->zl_destroy_txg = txg;
601 	zilog->zl_keep_first = keep_first;
602 
603 	if (!list_is_empty(&zilog->zl_lwb_list)) {
604 		ASSERT(zh->zh_claim_txg == 0);
605 		VERIFY(!keep_first);
606 		while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
607 			list_remove(&zilog->zl_lwb_list, lwb);
608 			if (lwb->lwb_buf != NULL)
609 				zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
610 			zio_free_zil(zilog->zl_spa, txg, &lwb->lwb_blk);
611 			kmem_cache_free(zil_lwb_cache, lwb);
612 		}
613 	} else if (!keep_first) {
614 		zil_destroy_sync(zilog, tx);
615 	}
616 	mutex_exit(&zilog->zl_lock);
617 
618 	dmu_tx_commit(tx);
619 }
620 
621 void
zil_destroy_sync(zilog_t * zilog,dmu_tx_t * tx)622 zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx)
623 {
624 	ASSERT(list_is_empty(&zilog->zl_lwb_list));
625 	(void) zil_parse(zilog, zil_free_log_block,
626 	    zil_free_log_record, tx, zilog->zl_header->zh_claim_txg);
627 }
628 
629 int
zil_claim(dsl_pool_t * dp,dsl_dataset_t * ds,void * txarg)630 zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg)
631 {
632 	dmu_tx_t *tx = txarg;
633 	uint64_t first_txg = dmu_tx_get_txg(tx);
634 	zilog_t *zilog;
635 	zil_header_t *zh;
636 	objset_t *os;
637 	int error;
638 
639 	error = dmu_objset_own_obj(dp, ds->ds_object,
640 	    DMU_OST_ANY, B_FALSE, FTAG, &os);
641 	if (error != 0) {
642 		/*
643 		 * EBUSY indicates that the objset is inconsistent, in which
644 		 * case it can not have a ZIL.
645 		 */
646 		if (error != EBUSY) {
647 			cmn_err(CE_WARN, "can't open objset for %llu, error %u",
648 			    (unsigned long long)ds->ds_object, error);
649 		}
650 		return (0);
651 	}
652 
653 	zilog = dmu_objset_zil(os);
654 	zh = zil_header_in_syncing_context(zilog);
655 
656 	if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR) {
657 		if (!BP_IS_HOLE(&zh->zh_log))
658 			zio_free_zil(zilog->zl_spa, first_txg, &zh->zh_log);
659 		BP_ZERO(&zh->zh_log);
660 		dsl_dataset_dirty(dmu_objset_ds(os), tx);
661 		dmu_objset_disown(os, FTAG);
662 		return (0);
663 	}
664 
665 	/*
666 	 * Claim all log blocks if we haven't already done so, and remember
667 	 * the highest claimed sequence number.  This ensures that if we can
668 	 * read only part of the log now (e.g. due to a missing device),
669 	 * but we can read the entire log later, we will not try to replay
670 	 * or destroy beyond the last block we successfully claimed.
671 	 */
672 	ASSERT3U(zh->zh_claim_txg, <=, first_txg);
673 	if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) {
674 		(void) zil_parse(zilog, zil_claim_log_block,
675 		    zil_claim_log_record, tx, first_txg);
676 		zh->zh_claim_txg = first_txg;
677 		zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq;
678 		zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq;
679 		if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1)
680 			zh->zh_flags |= ZIL_REPLAY_NEEDED;
681 		zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID;
682 		dsl_dataset_dirty(dmu_objset_ds(os), tx);
683 	}
684 
685 	ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1));
686 	dmu_objset_disown(os, FTAG);
687 	return (0);
688 }
689 
690 /*
691  * Check the log by walking the log chain.
692  * Checksum errors are ok as they indicate the end of the chain.
693  * Any other error (no device or read failure) returns an error.
694  */
695 /* ARGSUSED */
696 int
zil_check_log_chain(dsl_pool_t * dp,dsl_dataset_t * ds,void * tx)697 zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx)
698 {
699 	zilog_t *zilog;
700 	objset_t *os;
701 	blkptr_t *bp;
702 	int error;
703 
704 	ASSERT(tx == NULL);
705 
706 	error = dmu_objset_from_ds(ds, &os);
707 	if (error != 0) {
708 		cmn_err(CE_WARN, "can't open objset %llu, error %d",
709 		    (unsigned long long)ds->ds_object, error);
710 		return (0);
711 	}
712 
713 	zilog = dmu_objset_zil(os);
714 	bp = (blkptr_t *)&zilog->zl_header->zh_log;
715 
716 	/*
717 	 * Check the first block and determine if it's on a log device
718 	 * which may have been removed or faulted prior to loading this
719 	 * pool.  If so, there's no point in checking the rest of the log
720 	 * as its content should have already been synced to the pool.
721 	 */
722 	if (!BP_IS_HOLE(bp)) {
723 		vdev_t *vd;
724 		boolean_t valid = B_TRUE;
725 
726 		spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER);
727 		vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0]));
728 		if (vd->vdev_islog && vdev_is_dead(vd))
729 			valid = vdev_log_state_valid(vd);
730 		spa_config_exit(os->os_spa, SCL_STATE, FTAG);
731 
732 		if (!valid)
733 			return (0);
734 	}
735 
736 	/*
737 	 * Because tx == NULL, zil_claim_log_block() will not actually claim
738 	 * any blocks, but just determine whether it is possible to do so.
739 	 * In addition to checking the log chain, zil_claim_log_block()
740 	 * will invoke zio_claim() with a done func of spa_claim_notify(),
741 	 * which will update spa_max_claim_txg.  See spa_load() for details.
742 	 */
743 	error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx,
744 	    zilog->zl_header->zh_claim_txg ? -1ULL : spa_first_txg(os->os_spa));
745 
746 	return ((error == ECKSUM || error == ENOENT) ? 0 : error);
747 }
748 
749 static int
zil_vdev_compare(const void * x1,const void * x2)750 zil_vdev_compare(const void *x1, const void *x2)
751 {
752 	const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
753 	const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
754 
755 	if (v1 < v2)
756 		return (-1);
757 	if (v1 > v2)
758 		return (1);
759 
760 	return (0);
761 }
762 
763 void
zil_add_block(zilog_t * zilog,const blkptr_t * bp)764 zil_add_block(zilog_t *zilog, const blkptr_t *bp)
765 {
766 	avl_tree_t *t = &zilog->zl_vdev_tree;
767 	avl_index_t where;
768 	zil_vdev_node_t *zv, zvsearch;
769 	int ndvas = BP_GET_NDVAS(bp);
770 	int i;
771 
772 	if (zfs_nocacheflush)
773 		return;
774 
775 	ASSERT(zilog->zl_writer);
776 
777 	/*
778 	 * Even though we're zl_writer, we still need a lock because the
779 	 * zl_get_data() callbacks may have dmu_sync() done callbacks
780 	 * that will run concurrently.
781 	 */
782 	mutex_enter(&zilog->zl_vdev_lock);
783 	for (i = 0; i < ndvas; i++) {
784 		zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
785 		if (avl_find(t, &zvsearch, &where) == NULL) {
786 			zv = kmem_alloc(sizeof (*zv), KM_SLEEP);
787 			zv->zv_vdev = zvsearch.zv_vdev;
788 			avl_insert(t, zv, where);
789 		}
790 	}
791 	mutex_exit(&zilog->zl_vdev_lock);
792 }
793 
794 static void
zil_flush_vdevs(zilog_t * zilog)795 zil_flush_vdevs(zilog_t *zilog)
796 {
797 	spa_t *spa = zilog->zl_spa;
798 	avl_tree_t *t = &zilog->zl_vdev_tree;
799 	void *cookie = NULL;
800 	zil_vdev_node_t *zv;
801 	zio_t *zio;
802 
803 	ASSERT(zilog->zl_writer);
804 
805 	/*
806 	 * We don't need zl_vdev_lock here because we're the zl_writer,
807 	 * and all zl_get_data() callbacks are done.
808 	 */
809 	if (avl_numnodes(t) == 0)
810 		return;
811 
812 	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
813 
814 	zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
815 
816 	while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
817 		vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
818 		if (vd != NULL)
819 			zio_flush(zio, vd);
820 		kmem_free(zv, sizeof (*zv));
821 	}
822 
823 	/*
824 	 * Wait for all the flushes to complete.  Not all devices actually
825 	 * support the DKIOCFLUSHWRITECACHE ioctl, so it's OK if it fails.
826 	 */
827 	(void) zio_wait(zio);
828 
829 	spa_config_exit(spa, SCL_STATE, FTAG);
830 }
831 
832 /*
833  * Function called when a log block write completes
834  */
835 static void
zil_lwb_write_done(zio_t * zio)836 zil_lwb_write_done(zio_t *zio)
837 {
838 	lwb_t *lwb = zio->io_private;
839 	zilog_t *zilog = lwb->lwb_zilog;
840 	dmu_tx_t *tx = lwb->lwb_tx;
841 
842 	ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
843 	ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG);
844 	ASSERT(BP_GET_LEVEL(zio->io_bp) == 0);
845 	ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER);
846 	ASSERT(!BP_IS_GANG(zio->io_bp));
847 	ASSERT(!BP_IS_HOLE(zio->io_bp));
848 	ASSERT(BP_GET_FILL(zio->io_bp) == 0);
849 
850 	/*
851 	 * Ensure the lwb buffer pointer is cleared before releasing
852 	 * the txg. If we have had an allocation failure and
853 	 * the txg is waiting to sync then we want want zil_sync()
854 	 * to remove the lwb so that it's not picked up as the next new
855 	 * one in zil_commit_writer(). zil_sync() will only remove
856 	 * the lwb if lwb_buf is null.
857 	 */
858 	zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
859 	mutex_enter(&zilog->zl_lock);
860 	lwb->lwb_buf = NULL;
861 	lwb->lwb_tx = NULL;
862 	mutex_exit(&zilog->zl_lock);
863 
864 	/*
865 	 * Now that we've written this log block, we have a stable pointer
866 	 * to the next block in the chain, so it's OK to let the txg in
867 	 * which we allocated the next block sync.
868 	 */
869 	dmu_tx_commit(tx);
870 }
871 
872 /*
873  * Initialize the io for a log block.
874  */
875 static void
zil_lwb_write_init(zilog_t * zilog,lwb_t * lwb)876 zil_lwb_write_init(zilog_t *zilog, lwb_t *lwb)
877 {
878 	zbookmark_phys_t zb;
879 
880 	SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET],
881 	    ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
882 	    lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]);
883 
884 	if (zilog->zl_root_zio == NULL) {
885 		zilog->zl_root_zio = zio_root(zilog->zl_spa, NULL, NULL,
886 		    ZIO_FLAG_CANFAIL);
887 	}
888 	if (lwb->lwb_zio == NULL) {
889 		lwb->lwb_zio = zio_rewrite(zilog->zl_root_zio, zilog->zl_spa,
890 		    0, &lwb->lwb_blk, lwb->lwb_buf, BP_GET_LSIZE(&lwb->lwb_blk),
891 		    zil_lwb_write_done, lwb, ZIO_PRIORITY_SYNC_WRITE,
892 		    ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE, &zb);
893 	}
894 }
895 
896 /*
897  * Define a limited set of intent log block sizes.
898  *
899  * These must be a multiple of 4KB. Note only the amount used (again
900  * aligned to 4KB) actually gets written. However, we can't always just
901  * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
902  */
903 uint64_t zil_block_buckets[] = {
904     4096,		/* non TX_WRITE */
905     8192+4096,		/* data base */
906     32*1024 + 4096, 	/* NFS writes */
907     UINT64_MAX
908 };
909 
910 /*
911  * Use the slog as long as the logbias is 'latency' and the current commit size
912  * is less than the limit or the total list size is less than 2X the limit.
913  * Limit checking is disabled by setting zil_slog_limit to UINT64_MAX.
914  */
915 uint64_t zil_slog_limit = 1024 * 1024;
916 #define	USE_SLOG(zilog) (((zilog)->zl_logbias == ZFS_LOGBIAS_LATENCY) && \
917 	(((zilog)->zl_cur_used < zil_slog_limit) || \
918 	((zilog)->zl_itx_list_sz < (zil_slog_limit << 1))))
919 
920 /*
921  * Start a log block write and advance to the next log block.
922  * Calls are serialized.
923  */
924 static lwb_t *
zil_lwb_write_start(zilog_t * zilog,lwb_t * lwb)925 zil_lwb_write_start(zilog_t *zilog, lwb_t *lwb)
926 {
927 	lwb_t *nlwb = NULL;
928 	zil_chain_t *zilc;
929 	spa_t *spa = zilog->zl_spa;
930 	blkptr_t *bp;
931 	dmu_tx_t *tx;
932 	uint64_t txg;
933 	uint64_t zil_blksz, wsz;
934 	int i, error;
935 
936 	if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
937 		zilc = (zil_chain_t *)lwb->lwb_buf;
938 		bp = &zilc->zc_next_blk;
939 	} else {
940 		zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz);
941 		bp = &zilc->zc_next_blk;
942 	}
943 
944 	ASSERT(lwb->lwb_nused <= lwb->lwb_sz);
945 
946 	/*
947 	 * Allocate the next block and save its address in this block
948 	 * before writing it in order to establish the log chain.
949 	 * Note that if the allocation of nlwb synced before we wrote
950 	 * the block that points at it (lwb), we'd leak it if we crashed.
951 	 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
952 	 * We dirty the dataset to ensure that zil_sync() will be called
953 	 * to clean up in the event of allocation failure or I/O failure.
954 	 */
955 	tx = dmu_tx_create(zilog->zl_os);
956 	VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
957 	dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
958 	txg = dmu_tx_get_txg(tx);
959 
960 	lwb->lwb_tx = tx;
961 
962 	/*
963 	 * Log blocks are pre-allocated. Here we select the size of the next
964 	 * block, based on size used in the last block.
965 	 * - first find the smallest bucket that will fit the block from a
966 	 *   limited set of block sizes. This is because it's faster to write
967 	 *   blocks allocated from the same metaslab as they are adjacent or
968 	 *   close.
969 	 * - next find the maximum from the new suggested size and an array of
970 	 *   previous sizes. This lessens a picket fence effect of wrongly
971 	 *   guesssing the size if we have a stream of say 2k, 64k, 2k, 64k
972 	 *   requests.
973 	 *
974 	 * Note we only write what is used, but we can't just allocate
975 	 * the maximum block size because we can exhaust the available
976 	 * pool log space.
977 	 */
978 	zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t);
979 	for (i = 0; zil_blksz > zil_block_buckets[i]; i++)
980 		continue;
981 	zil_blksz = zil_block_buckets[i];
982 	if (zil_blksz == UINT64_MAX)
983 		zil_blksz = SPA_OLD_MAXBLOCKSIZE;
984 	zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz;
985 	for (i = 0; i < ZIL_PREV_BLKS; i++)
986 		zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]);
987 	zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1);
988 
989 	BP_ZERO(bp);
990 	/* pass the old blkptr in order to spread log blocks across devs */
991 	error = zio_alloc_zil(spa, txg, bp, &lwb->lwb_blk, zil_blksz,
992 	    USE_SLOG(zilog));
993 	if (error == 0) {
994 		ASSERT3U(bp->blk_birth, ==, txg);
995 		bp->blk_cksum = lwb->lwb_blk.blk_cksum;
996 		bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++;
997 
998 		/*
999 		 * Allocate a new log write buffer (lwb).
1000 		 */
1001 		nlwb = zil_alloc_lwb(zilog, bp, txg);
1002 
1003 		/* Record the block for later vdev flushing */
1004 		zil_add_block(zilog, &lwb->lwb_blk);
1005 	}
1006 
1007 	if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
1008 		/* For Slim ZIL only write what is used. */
1009 		wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t);
1010 		ASSERT3U(wsz, <=, lwb->lwb_sz);
1011 		zio_shrink(lwb->lwb_zio, wsz);
1012 
1013 	} else {
1014 		wsz = lwb->lwb_sz;
1015 	}
1016 
1017 	zilc->zc_pad = 0;
1018 	zilc->zc_nused = lwb->lwb_nused;
1019 	zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum;
1020 
1021 	/*
1022 	 * clear unused data for security
1023 	 */
1024 	bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused);
1025 
1026 	zio_nowait(lwb->lwb_zio); /* Kick off the write for the old log block */
1027 
1028 	/*
1029 	 * If there was an allocation failure then nlwb will be null which
1030 	 * forces a txg_wait_synced().
1031 	 */
1032 	return (nlwb);
1033 }
1034 
1035 static lwb_t *
zil_lwb_commit(zilog_t * zilog,itx_t * itx,lwb_t * lwb)1036 zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb)
1037 {
1038 	lr_t *lrc = &itx->itx_lr; /* common log record */
1039 	lr_write_t *lrw = (lr_write_t *)lrc;
1040 	char *lr_buf;
1041 	uint64_t txg = lrc->lrc_txg;
1042 	uint64_t reclen = lrc->lrc_reclen;
1043 	uint64_t dlen = 0;
1044 
1045 	if (lwb == NULL)
1046 		return (NULL);
1047 
1048 	ASSERT(lwb->lwb_buf != NULL);
1049 	ASSERT(zilog_is_dirty(zilog) ||
1050 	    spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
1051 
1052 	if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY)
1053 		dlen = P2ROUNDUP_TYPED(
1054 		    lrw->lr_length, sizeof (uint64_t), uint64_t);
1055 
1056 	zilog->zl_cur_used += (reclen + dlen);
1057 
1058 	zil_lwb_write_init(zilog, lwb);
1059 
1060 	/*
1061 	 * If this record won't fit in the current log block, start a new one.
1062 	 */
1063 	if (lwb->lwb_nused + reclen + dlen > lwb->lwb_sz) {
1064 		lwb = zil_lwb_write_start(zilog, lwb);
1065 		if (lwb == NULL)
1066 			return (NULL);
1067 		zil_lwb_write_init(zilog, lwb);
1068 		ASSERT(LWB_EMPTY(lwb));
1069 		if (lwb->lwb_nused + reclen + dlen > lwb->lwb_sz) {
1070 			txg_wait_synced(zilog->zl_dmu_pool, txg);
1071 			return (lwb);
1072 		}
1073 	}
1074 
1075 	lr_buf = lwb->lwb_buf + lwb->lwb_nused;
1076 	bcopy(lrc, lr_buf, reclen);
1077 	lrc = (lr_t *)lr_buf;
1078 	lrw = (lr_write_t *)lrc;
1079 
1080 	/*
1081 	 * If it's a write, fetch the data or get its blkptr as appropriate.
1082 	 */
1083 	if (lrc->lrc_txtype == TX_WRITE) {
1084 		if (txg > spa_freeze_txg(zilog->zl_spa))
1085 			txg_wait_synced(zilog->zl_dmu_pool, txg);
1086 		if (itx->itx_wr_state != WR_COPIED) {
1087 			char *dbuf;
1088 			int error;
1089 
1090 			if (dlen) {
1091 				ASSERT(itx->itx_wr_state == WR_NEED_COPY);
1092 				dbuf = lr_buf + reclen;
1093 				lrw->lr_common.lrc_reclen += dlen;
1094 			} else {
1095 				ASSERT(itx->itx_wr_state == WR_INDIRECT);
1096 				dbuf = NULL;
1097 			}
1098 			error = zilog->zl_get_data(
1099 			    itx->itx_private, lrw, dbuf, lwb->lwb_zio);
1100 			if (error == EIO) {
1101 				txg_wait_synced(zilog->zl_dmu_pool, txg);
1102 				return (lwb);
1103 			}
1104 			if (error != 0) {
1105 				ASSERT(error == ENOENT || error == EEXIST ||
1106 				    error == EALREADY);
1107 				return (lwb);
1108 			}
1109 		}
1110 	}
1111 
1112 	/*
1113 	 * We're actually making an entry, so update lrc_seq to be the
1114 	 * log record sequence number.  Note that this is generally not
1115 	 * equal to the itx sequence number because not all transactions
1116 	 * are synchronous, and sometimes spa_sync() gets there first.
1117 	 */
1118 	lrc->lrc_seq = ++zilog->zl_lr_seq; /* we are single threaded */
1119 	lwb->lwb_nused += reclen + dlen;
1120 	lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
1121 	ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz);
1122 	ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t)));
1123 
1124 	return (lwb);
1125 }
1126 
1127 itx_t *
zil_itx_create(uint64_t txtype,size_t lrsize)1128 zil_itx_create(uint64_t txtype, size_t lrsize)
1129 {
1130 	itx_t *itx;
1131 
1132 	lrsize = P2ROUNDUP_TYPED(lrsize, sizeof (uint64_t), size_t);
1133 
1134 	itx = kmem_alloc(offsetof(itx_t, itx_lr) + lrsize, KM_SLEEP);
1135 	itx->itx_lr.lrc_txtype = txtype;
1136 	itx->itx_lr.lrc_reclen = lrsize;
1137 	itx->itx_sod = lrsize; /* if write & WR_NEED_COPY will be increased */
1138 	itx->itx_lr.lrc_seq = 0;	/* defensive */
1139 	itx->itx_sync = B_TRUE;		/* default is synchronous */
1140 
1141 	return (itx);
1142 }
1143 
1144 void
zil_itx_destroy(itx_t * itx)1145 zil_itx_destroy(itx_t *itx)
1146 {
1147 	kmem_free(itx, offsetof(itx_t, itx_lr) + itx->itx_lr.lrc_reclen);
1148 }
1149 
1150 /*
1151  * Free up the sync and async itxs. The itxs_t has already been detached
1152  * so no locks are needed.
1153  */
1154 static void
zil_itxg_clean(itxs_t * itxs)1155 zil_itxg_clean(itxs_t *itxs)
1156 {
1157 	itx_t *itx;
1158 	list_t *list;
1159 	avl_tree_t *t;
1160 	void *cookie;
1161 	itx_async_node_t *ian;
1162 
1163 	list = &itxs->i_sync_list;
1164 	while ((itx = list_head(list)) != NULL) {
1165 		list_remove(list, itx);
1166 		kmem_free(itx, offsetof(itx_t, itx_lr) +
1167 		    itx->itx_lr.lrc_reclen);
1168 	}
1169 
1170 	cookie = NULL;
1171 	t = &itxs->i_async_tree;
1172 	while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
1173 		list = &ian->ia_list;
1174 		while ((itx = list_head(list)) != NULL) {
1175 			list_remove(list, itx);
1176 			kmem_free(itx, offsetof(itx_t, itx_lr) +
1177 			    itx->itx_lr.lrc_reclen);
1178 		}
1179 		list_destroy(list);
1180 		kmem_free(ian, sizeof (itx_async_node_t));
1181 	}
1182 	avl_destroy(t);
1183 
1184 	kmem_free(itxs, sizeof (itxs_t));
1185 }
1186 
1187 static int
zil_aitx_compare(const void * x1,const void * x2)1188 zil_aitx_compare(const void *x1, const void *x2)
1189 {
1190 	const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
1191 	const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
1192 
1193 	if (o1 < o2)
1194 		return (-1);
1195 	if (o1 > o2)
1196 		return (1);
1197 
1198 	return (0);
1199 }
1200 
1201 /*
1202  * Remove all async itx with the given oid.
1203  */
1204 static void
zil_remove_async(zilog_t * zilog,uint64_t oid)1205 zil_remove_async(zilog_t *zilog, uint64_t oid)
1206 {
1207 	uint64_t otxg, txg;
1208 	itx_async_node_t *ian;
1209 	avl_tree_t *t;
1210 	avl_index_t where;
1211 	list_t clean_list;
1212 	itx_t *itx;
1213 
1214 	ASSERT(oid != 0);
1215 	list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node));
1216 
1217 	if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1218 		otxg = ZILTEST_TXG;
1219 	else
1220 		otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1221 
1222 	for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1223 		itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1224 
1225 		mutex_enter(&itxg->itxg_lock);
1226 		if (itxg->itxg_txg != txg) {
1227 			mutex_exit(&itxg->itxg_lock);
1228 			continue;
1229 		}
1230 
1231 		/*
1232 		 * Locate the object node and append its list.
1233 		 */
1234 		t = &itxg->itxg_itxs->i_async_tree;
1235 		ian = avl_find(t, &oid, &where);
1236 		if (ian != NULL)
1237 			list_move_tail(&clean_list, &ian->ia_list);
1238 		mutex_exit(&itxg->itxg_lock);
1239 	}
1240 	while ((itx = list_head(&clean_list)) != NULL) {
1241 		list_remove(&clean_list, itx);
1242 		kmem_free(itx, offsetof(itx_t, itx_lr) +
1243 		    itx->itx_lr.lrc_reclen);
1244 	}
1245 	list_destroy(&clean_list);
1246 }
1247 
1248 void
zil_itx_assign(zilog_t * zilog,itx_t * itx,dmu_tx_t * tx)1249 zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx)
1250 {
1251 	uint64_t txg;
1252 	itxg_t *itxg;
1253 	itxs_t *itxs, *clean = NULL;
1254 
1255 	/*
1256 	 * Object ids can be re-instantiated in the next txg so
1257 	 * remove any async transactions to avoid future leaks.
1258 	 * This can happen if a fsync occurs on the re-instantiated
1259 	 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
1260 	 * the new file data and flushes a write record for the old object.
1261 	 */
1262 	if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_REMOVE)
1263 		zil_remove_async(zilog, itx->itx_oid);
1264 
1265 	/*
1266 	 * Ensure the data of a renamed file is committed before the rename.
1267 	 */
1268 	if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME)
1269 		zil_async_to_sync(zilog, itx->itx_oid);
1270 
1271 	if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX)
1272 		txg = ZILTEST_TXG;
1273 	else
1274 		txg = dmu_tx_get_txg(tx);
1275 
1276 	itxg = &zilog->zl_itxg[txg & TXG_MASK];
1277 	mutex_enter(&itxg->itxg_lock);
1278 	itxs = itxg->itxg_itxs;
1279 	if (itxg->itxg_txg != txg) {
1280 		if (itxs != NULL) {
1281 			/*
1282 			 * The zil_clean callback hasn't got around to cleaning
1283 			 * this itxg. Save the itxs for release below.
1284 			 * This should be rare.
1285 			 */
1286 			atomic_add_64(&zilog->zl_itx_list_sz, -itxg->itxg_sod);
1287 			itxg->itxg_sod = 0;
1288 			clean = itxg->itxg_itxs;
1289 		}
1290 		ASSERT(itxg->itxg_sod == 0);
1291 		itxg->itxg_txg = txg;
1292 		itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t), KM_SLEEP);
1293 
1294 		list_create(&itxs->i_sync_list, sizeof (itx_t),
1295 		    offsetof(itx_t, itx_node));
1296 		avl_create(&itxs->i_async_tree, zil_aitx_compare,
1297 		    sizeof (itx_async_node_t),
1298 		    offsetof(itx_async_node_t, ia_node));
1299 	}
1300 	if (itx->itx_sync) {
1301 		list_insert_tail(&itxs->i_sync_list, itx);
1302 		atomic_add_64(&zilog->zl_itx_list_sz, itx->itx_sod);
1303 		itxg->itxg_sod += itx->itx_sod;
1304 	} else {
1305 		avl_tree_t *t = &itxs->i_async_tree;
1306 		uint64_t foid = ((lr_ooo_t *)&itx->itx_lr)->lr_foid;
1307 		itx_async_node_t *ian;
1308 		avl_index_t where;
1309 
1310 		ian = avl_find(t, &foid, &where);
1311 		if (ian == NULL) {
1312 			ian = kmem_alloc(sizeof (itx_async_node_t), KM_SLEEP);
1313 			list_create(&ian->ia_list, sizeof (itx_t),
1314 			    offsetof(itx_t, itx_node));
1315 			ian->ia_foid = foid;
1316 			avl_insert(t, ian, where);
1317 		}
1318 		list_insert_tail(&ian->ia_list, itx);
1319 	}
1320 
1321 	itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx);
1322 	zilog_dirty(zilog, txg);
1323 	mutex_exit(&itxg->itxg_lock);
1324 
1325 	/* Release the old itxs now we've dropped the lock */
1326 	if (clean != NULL)
1327 		zil_itxg_clean(clean);
1328 }
1329 
1330 /*
1331  * If there are any in-memory intent log transactions which have now been
1332  * synced then start up a taskq to free them. We should only do this after we
1333  * have written out the uberblocks (i.e. txg has been comitted) so that
1334  * don't inadvertently clean out in-memory log records that would be required
1335  * by zil_commit().
1336  */
1337 void
zil_clean(zilog_t * zilog,uint64_t synced_txg)1338 zil_clean(zilog_t *zilog, uint64_t synced_txg)
1339 {
1340 	itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK];
1341 	itxs_t *clean_me;
1342 
1343 	mutex_enter(&itxg->itxg_lock);
1344 	if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) {
1345 		mutex_exit(&itxg->itxg_lock);
1346 		return;
1347 	}
1348 	ASSERT3U(itxg->itxg_txg, <=, synced_txg);
1349 	ASSERT(itxg->itxg_txg != 0);
1350 	ASSERT(zilog->zl_clean_taskq != NULL);
1351 	atomic_add_64(&zilog->zl_itx_list_sz, -itxg->itxg_sod);
1352 	itxg->itxg_sod = 0;
1353 	clean_me = itxg->itxg_itxs;
1354 	itxg->itxg_itxs = NULL;
1355 	itxg->itxg_txg = 0;
1356 	mutex_exit(&itxg->itxg_lock);
1357 	/*
1358 	 * Preferably start a task queue to free up the old itxs but
1359 	 * if taskq_dispatch can't allocate resources to do that then
1360 	 * free it in-line. This should be rare. Note, using TQ_SLEEP
1361 	 * created a bad performance problem.
1362 	 */
1363 	if (taskq_dispatch(zilog->zl_clean_taskq,
1364 	    (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP) == NULL)
1365 		zil_itxg_clean(clean_me);
1366 }
1367 
1368 /*
1369  * Get the list of itxs to commit into zl_itx_commit_list.
1370  */
1371 static void
zil_get_commit_list(zilog_t * zilog)1372 zil_get_commit_list(zilog_t *zilog)
1373 {
1374 	uint64_t otxg, txg;
1375 	list_t *commit_list = &zilog->zl_itx_commit_list;
1376 	uint64_t push_sod = 0;
1377 
1378 	if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1379 		otxg = ZILTEST_TXG;
1380 	else
1381 		otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1382 
1383 	for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1384 		itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1385 
1386 		mutex_enter(&itxg->itxg_lock);
1387 		if (itxg->itxg_txg != txg) {
1388 			mutex_exit(&itxg->itxg_lock);
1389 			continue;
1390 		}
1391 
1392 		list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list);
1393 		push_sod += itxg->itxg_sod;
1394 		itxg->itxg_sod = 0;
1395 
1396 		mutex_exit(&itxg->itxg_lock);
1397 	}
1398 	atomic_add_64(&zilog->zl_itx_list_sz, -push_sod);
1399 }
1400 
1401 /*
1402  * Move the async itxs for a specified object to commit into sync lists.
1403  */
1404 static void
zil_async_to_sync(zilog_t * zilog,uint64_t foid)1405 zil_async_to_sync(zilog_t *zilog, uint64_t foid)
1406 {
1407 	uint64_t otxg, txg;
1408 	itx_async_node_t *ian;
1409 	avl_tree_t *t;
1410 	avl_index_t where;
1411 
1412 	if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1413 		otxg = ZILTEST_TXG;
1414 	else
1415 		otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1416 
1417 	for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1418 		itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1419 
1420 		mutex_enter(&itxg->itxg_lock);
1421 		if (itxg->itxg_txg != txg) {
1422 			mutex_exit(&itxg->itxg_lock);
1423 			continue;
1424 		}
1425 
1426 		/*
1427 		 * If a foid is specified then find that node and append its
1428 		 * list. Otherwise walk the tree appending all the lists
1429 		 * to the sync list. We add to the end rather than the
1430 		 * beginning to ensure the create has happened.
1431 		 */
1432 		t = &itxg->itxg_itxs->i_async_tree;
1433 		if (foid != 0) {
1434 			ian = avl_find(t, &foid, &where);
1435 			if (ian != NULL) {
1436 				list_move_tail(&itxg->itxg_itxs->i_sync_list,
1437 				    &ian->ia_list);
1438 			}
1439 		} else {
1440 			void *cookie = NULL;
1441 
1442 			while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
1443 				list_move_tail(&itxg->itxg_itxs->i_sync_list,
1444 				    &ian->ia_list);
1445 				list_destroy(&ian->ia_list);
1446 				kmem_free(ian, sizeof (itx_async_node_t));
1447 			}
1448 		}
1449 		mutex_exit(&itxg->itxg_lock);
1450 	}
1451 }
1452 
1453 static void
zil_commit_writer(zilog_t * zilog)1454 zil_commit_writer(zilog_t *zilog)
1455 {
1456 	uint64_t txg;
1457 	itx_t *itx;
1458 	lwb_t *lwb;
1459 	spa_t *spa = zilog->zl_spa;
1460 	int error = 0;
1461 
1462 	ASSERT(zilog->zl_root_zio == NULL);
1463 
1464 	mutex_exit(&zilog->zl_lock);
1465 
1466 	zil_get_commit_list(zilog);
1467 
1468 	/*
1469 	 * Return if there's nothing to commit before we dirty the fs by
1470 	 * calling zil_create().
1471 	 */
1472 	if (list_head(&zilog->zl_itx_commit_list) == NULL) {
1473 		mutex_enter(&zilog->zl_lock);
1474 		return;
1475 	}
1476 
1477 	if (zilog->zl_suspend) {
1478 		lwb = NULL;
1479 	} else {
1480 		lwb = list_tail(&zilog->zl_lwb_list);
1481 		if (lwb == NULL)
1482 			lwb = zil_create(zilog);
1483 	}
1484 
1485 	DTRACE_PROBE1(zil__cw1, zilog_t *, zilog);
1486 	while (itx = list_head(&zilog->zl_itx_commit_list)) {
1487 		txg = itx->itx_lr.lrc_txg;
1488 		ASSERT(txg);
1489 
1490 		if (txg > spa_last_synced_txg(spa) || txg > spa_freeze_txg(spa))
1491 			lwb = zil_lwb_commit(zilog, itx, lwb);
1492 		list_remove(&zilog->zl_itx_commit_list, itx);
1493 		kmem_free(itx, offsetof(itx_t, itx_lr)
1494 		    + itx->itx_lr.lrc_reclen);
1495 	}
1496 	DTRACE_PROBE1(zil__cw2, zilog_t *, zilog);
1497 
1498 	/* write the last block out */
1499 	if (lwb != NULL && lwb->lwb_zio != NULL)
1500 		lwb = zil_lwb_write_start(zilog, lwb);
1501 
1502 	zilog->zl_cur_used = 0;
1503 
1504 	/*
1505 	 * Wait if necessary for the log blocks to be on stable storage.
1506 	 */
1507 	if (zilog->zl_root_zio) {
1508 		error = zio_wait(zilog->zl_root_zio);
1509 		zilog->zl_root_zio = NULL;
1510 		zil_flush_vdevs(zilog);
1511 	}
1512 
1513 	if (error || lwb == NULL)
1514 		txg_wait_synced(zilog->zl_dmu_pool, 0);
1515 
1516 	mutex_enter(&zilog->zl_lock);
1517 
1518 	/*
1519 	 * Remember the highest committed log sequence number for ztest.
1520 	 * We only update this value when all the log writes succeeded,
1521 	 * because ztest wants to ASSERT that it got the whole log chain.
1522 	 */
1523 	if (error == 0 && lwb != NULL)
1524 		zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
1525 }
1526 
1527 /*
1528  * Commit zfs transactions to stable storage.
1529  * If foid is 0 push out all transactions, otherwise push only those
1530  * for that object or might reference that object.
1531  *
1532  * itxs are committed in batches. In a heavily stressed zil there will be
1533  * a commit writer thread who is writing out a bunch of itxs to the log
1534  * for a set of committing threads (cthreads) in the same batch as the writer.
1535  * Those cthreads are all waiting on the same cv for that batch.
1536  *
1537  * There will also be a different and growing batch of threads that are
1538  * waiting to commit (qthreads). When the committing batch completes
1539  * a transition occurs such that the cthreads exit and the qthreads become
1540  * cthreads. One of the new cthreads becomes the writer thread for the
1541  * batch. Any new threads arriving become new qthreads.
1542  *
1543  * Only 2 condition variables are needed and there's no transition
1544  * between the two cvs needed. They just flip-flop between qthreads
1545  * and cthreads.
1546  *
1547  * Using this scheme we can efficiently wakeup up only those threads
1548  * that have been committed.
1549  */
1550 void
zil_commit(zilog_t * zilog,uint64_t foid)1551 zil_commit(zilog_t *zilog, uint64_t foid)
1552 {
1553 	uint64_t mybatch;
1554 
1555 	if (zilog->zl_sync == ZFS_SYNC_DISABLED)
1556 		return;
1557 
1558 	/* move the async itxs for the foid to the sync queues */
1559 	zil_async_to_sync(zilog, foid);
1560 
1561 	mutex_enter(&zilog->zl_lock);
1562 	mybatch = zilog->zl_next_batch;
1563 	while (zilog->zl_writer) {
1564 		cv_wait(&zilog->zl_cv_batch[mybatch & 1], &zilog->zl_lock);
1565 		if (mybatch <= zilog->zl_com_batch) {
1566 			mutex_exit(&zilog->zl_lock);
1567 			return;
1568 		}
1569 	}
1570 
1571 	zilog->zl_next_batch++;
1572 	zilog->zl_writer = B_TRUE;
1573 	zil_commit_writer(zilog);
1574 	zilog->zl_com_batch = mybatch;
1575 	zilog->zl_writer = B_FALSE;
1576 	mutex_exit(&zilog->zl_lock);
1577 
1578 	/* wake up one thread to become the next writer */
1579 	cv_signal(&zilog->zl_cv_batch[(mybatch+1) & 1]);
1580 
1581 	/* wake up all threads waiting for this batch to be committed */
1582 	cv_broadcast(&zilog->zl_cv_batch[mybatch & 1]);
1583 }
1584 
1585 /*
1586  * Called in syncing context to free committed log blocks and update log header.
1587  */
1588 void
zil_sync(zilog_t * zilog,dmu_tx_t * tx)1589 zil_sync(zilog_t *zilog, dmu_tx_t *tx)
1590 {
1591 	zil_header_t *zh = zil_header_in_syncing_context(zilog);
1592 	uint64_t txg = dmu_tx_get_txg(tx);
1593 	spa_t *spa = zilog->zl_spa;
1594 	uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK];
1595 	lwb_t *lwb;
1596 
1597 	/*
1598 	 * We don't zero out zl_destroy_txg, so make sure we don't try
1599 	 * to destroy it twice.
1600 	 */
1601 	if (spa_sync_pass(spa) != 1)
1602 		return;
1603 
1604 	mutex_enter(&zilog->zl_lock);
1605 
1606 	ASSERT(zilog->zl_stop_sync == 0);
1607 
1608 	if (*replayed_seq != 0) {
1609 		ASSERT(zh->zh_replay_seq < *replayed_seq);
1610 		zh->zh_replay_seq = *replayed_seq;
1611 		*replayed_seq = 0;
1612 	}
1613 
1614 	if (zilog->zl_destroy_txg == txg) {
1615 		blkptr_t blk = zh->zh_log;
1616 
1617 		ASSERT(list_head(&zilog->zl_lwb_list) == NULL);
1618 
1619 		bzero(zh, sizeof (zil_header_t));
1620 		bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq));
1621 
1622 		if (zilog->zl_keep_first) {
1623 			/*
1624 			 * If this block was part of log chain that couldn't
1625 			 * be claimed because a device was missing during
1626 			 * zil_claim(), but that device later returns,
1627 			 * then this block could erroneously appear valid.
1628 			 * To guard against this, assign a new GUID to the new
1629 			 * log chain so it doesn't matter what blk points to.
1630 			 */
1631 			zil_init_log_chain(zilog, &blk);
1632 			zh->zh_log = blk;
1633 		}
1634 	}
1635 
1636 	while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
1637 		zh->zh_log = lwb->lwb_blk;
1638 		if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg)
1639 			break;
1640 		list_remove(&zilog->zl_lwb_list, lwb);
1641 		zio_free_zil(spa, txg, &lwb->lwb_blk);
1642 		kmem_cache_free(zil_lwb_cache, lwb);
1643 
1644 		/*
1645 		 * If we don't have anything left in the lwb list then
1646 		 * we've had an allocation failure and we need to zero
1647 		 * out the zil_header blkptr so that we don't end
1648 		 * up freeing the same block twice.
1649 		 */
1650 		if (list_head(&zilog->zl_lwb_list) == NULL)
1651 			BP_ZERO(&zh->zh_log);
1652 	}
1653 	mutex_exit(&zilog->zl_lock);
1654 }
1655 
1656 void
zil_init(void)1657 zil_init(void)
1658 {
1659 	zil_lwb_cache = kmem_cache_create("zil_lwb_cache",
1660 	    sizeof (struct lwb), 0, NULL, NULL, NULL, NULL, NULL, 0);
1661 }
1662 
1663 void
zil_fini(void)1664 zil_fini(void)
1665 {
1666 	kmem_cache_destroy(zil_lwb_cache);
1667 }
1668 
1669 void
zil_set_sync(zilog_t * zilog,uint64_t sync)1670 zil_set_sync(zilog_t *zilog, uint64_t sync)
1671 {
1672 	zilog->zl_sync = sync;
1673 }
1674 
1675 void
zil_set_logbias(zilog_t * zilog,uint64_t logbias)1676 zil_set_logbias(zilog_t *zilog, uint64_t logbias)
1677 {
1678 	zilog->zl_logbias = logbias;
1679 }
1680 
1681 zilog_t *
zil_alloc(objset_t * os,zil_header_t * zh_phys)1682 zil_alloc(objset_t *os, zil_header_t *zh_phys)
1683 {
1684 	zilog_t *zilog;
1685 
1686 	zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
1687 
1688 	zilog->zl_header = zh_phys;
1689 	zilog->zl_os = os;
1690 	zilog->zl_spa = dmu_objset_spa(os);
1691 	zilog->zl_dmu_pool = dmu_objset_pool(os);
1692 	zilog->zl_destroy_txg = TXG_INITIAL - 1;
1693 	zilog->zl_logbias = dmu_objset_logbias(os);
1694 	zilog->zl_sync = dmu_objset_syncprop(os);
1695 	zilog->zl_next_batch = 1;
1696 
1697 	mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
1698 
1699 	for (int i = 0; i < TXG_SIZE; i++) {
1700 		mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
1701 		    MUTEX_DEFAULT, NULL);
1702 	}
1703 
1704 	list_create(&zilog->zl_lwb_list, sizeof (lwb_t),
1705 	    offsetof(lwb_t, lwb_node));
1706 
1707 	list_create(&zilog->zl_itx_commit_list, sizeof (itx_t),
1708 	    offsetof(itx_t, itx_node));
1709 
1710 	mutex_init(&zilog->zl_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
1711 
1712 	avl_create(&zilog->zl_vdev_tree, zil_vdev_compare,
1713 	    sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
1714 
1715 	cv_init(&zilog->zl_cv_writer, NULL, CV_DEFAULT, NULL);
1716 	cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL);
1717 	cv_init(&zilog->zl_cv_batch[0], NULL, CV_DEFAULT, NULL);
1718 	cv_init(&zilog->zl_cv_batch[1], NULL, CV_DEFAULT, NULL);
1719 
1720 	return (zilog);
1721 }
1722 
1723 void
zil_free(zilog_t * zilog)1724 zil_free(zilog_t *zilog)
1725 {
1726 	zilog->zl_stop_sync = 1;
1727 
1728 	ASSERT0(zilog->zl_suspend);
1729 	ASSERT0(zilog->zl_suspending);
1730 
1731 	ASSERT(list_is_empty(&zilog->zl_lwb_list));
1732 	list_destroy(&zilog->zl_lwb_list);
1733 
1734 	avl_destroy(&zilog->zl_vdev_tree);
1735 	mutex_destroy(&zilog->zl_vdev_lock);
1736 
1737 	ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
1738 	list_destroy(&zilog->zl_itx_commit_list);
1739 
1740 	for (int i = 0; i < TXG_SIZE; i++) {
1741 		/*
1742 		 * It's possible for an itx to be generated that doesn't dirty
1743 		 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
1744 		 * callback to remove the entry. We remove those here.
1745 		 *
1746 		 * Also free up the ziltest itxs.
1747 		 */
1748 		if (zilog->zl_itxg[i].itxg_itxs)
1749 			zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs);
1750 		mutex_destroy(&zilog->zl_itxg[i].itxg_lock);
1751 	}
1752 
1753 	mutex_destroy(&zilog->zl_lock);
1754 
1755 	cv_destroy(&zilog->zl_cv_writer);
1756 	cv_destroy(&zilog->zl_cv_suspend);
1757 	cv_destroy(&zilog->zl_cv_batch[0]);
1758 	cv_destroy(&zilog->zl_cv_batch[1]);
1759 
1760 	kmem_free(zilog, sizeof (zilog_t));
1761 }
1762 
1763 /*
1764  * Open an intent log.
1765  */
1766 zilog_t *
zil_open(objset_t * os,zil_get_data_t * get_data)1767 zil_open(objset_t *os, zil_get_data_t *get_data)
1768 {
1769 	zilog_t *zilog = dmu_objset_zil(os);
1770 
1771 	ASSERT(zilog->zl_clean_taskq == NULL);
1772 	ASSERT(zilog->zl_get_data == NULL);
1773 	ASSERT(list_is_empty(&zilog->zl_lwb_list));
1774 
1775 	zilog->zl_get_data = get_data;
1776 	zilog->zl_clean_taskq = taskq_create("zil_clean", 1, minclsyspri,
1777 	    2, 2, TASKQ_PREPOPULATE);
1778 
1779 	return (zilog);
1780 }
1781 
1782 /*
1783  * Close an intent log.
1784  */
1785 void
zil_close(zilog_t * zilog)1786 zil_close(zilog_t *zilog)
1787 {
1788 	lwb_t *lwb;
1789 	uint64_t txg = 0;
1790 
1791 	zil_commit(zilog, 0); /* commit all itx */
1792 
1793 	/*
1794 	 * The lwb_max_txg for the stubby lwb will reflect the last activity
1795 	 * for the zil.  After a txg_wait_synced() on the txg we know all the
1796 	 * callbacks have occurred that may clean the zil.  Only then can we
1797 	 * destroy the zl_clean_taskq.
1798 	 */
1799 	mutex_enter(&zilog->zl_lock);
1800 	lwb = list_tail(&zilog->zl_lwb_list);
1801 	if (lwb != NULL)
1802 		txg = lwb->lwb_max_txg;
1803 	mutex_exit(&zilog->zl_lock);
1804 	if (txg)
1805 		txg_wait_synced(zilog->zl_dmu_pool, txg);
1806 	ASSERT(!zilog_is_dirty(zilog));
1807 
1808 	taskq_destroy(zilog->zl_clean_taskq);
1809 	zilog->zl_clean_taskq = NULL;
1810 	zilog->zl_get_data = NULL;
1811 
1812 	/*
1813 	 * We should have only one LWB left on the list; remove it now.
1814 	 */
1815 	mutex_enter(&zilog->zl_lock);
1816 	lwb = list_head(&zilog->zl_lwb_list);
1817 	if (lwb != NULL) {
1818 		ASSERT(lwb == list_tail(&zilog->zl_lwb_list));
1819 		list_remove(&zilog->zl_lwb_list, lwb);
1820 		zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
1821 		kmem_cache_free(zil_lwb_cache, lwb);
1822 	}
1823 	mutex_exit(&zilog->zl_lock);
1824 }
1825 
1826 static char *suspend_tag = "zil suspending";
1827 
1828 /*
1829  * Suspend an intent log.  While in suspended mode, we still honor
1830  * synchronous semantics, but we rely on txg_wait_synced() to do it.
1831  * On old version pools, we suspend the log briefly when taking a
1832  * snapshot so that it will have an empty intent log.
1833  *
1834  * Long holds are not really intended to be used the way we do here --
1835  * held for such a short time.  A concurrent caller of dsl_dataset_long_held()
1836  * could fail.  Therefore we take pains to only put a long hold if it is
1837  * actually necessary.  Fortunately, it will only be necessary if the
1838  * objset is currently mounted (or the ZVOL equivalent).  In that case it
1839  * will already have a long hold, so we are not really making things any worse.
1840  *
1841  * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
1842  * zvol_state_t), and use their mechanism to prevent their hold from being
1843  * dropped (e.g. VFS_HOLD()).  However, that would be even more pain for
1844  * very little gain.
1845  *
1846  * if cookiep == NULL, this does both the suspend & resume.
1847  * Otherwise, it returns with the dataset "long held", and the cookie
1848  * should be passed into zil_resume().
1849  */
1850 int
zil_suspend(const char * osname,void ** cookiep)1851 zil_suspend(const char *osname, void **cookiep)
1852 {
1853 	objset_t *os;
1854 	zilog_t *zilog;
1855 	const zil_header_t *zh;
1856 	int error;
1857 
1858 	error = dmu_objset_hold(osname, suspend_tag, &os);
1859 	if (error != 0)
1860 		return (error);
1861 	zilog = dmu_objset_zil(os);
1862 
1863 	mutex_enter(&zilog->zl_lock);
1864 	zh = zilog->zl_header;
1865 
1866 	if (zh->zh_flags & ZIL_REPLAY_NEEDED) {		/* unplayed log */
1867 		mutex_exit(&zilog->zl_lock);
1868 		dmu_objset_rele(os, suspend_tag);
1869 		return (SET_ERROR(EBUSY));
1870 	}
1871 
1872 	/*
1873 	 * Don't put a long hold in the cases where we can avoid it.  This
1874 	 * is when there is no cookie so we are doing a suspend & resume
1875 	 * (i.e. called from zil_vdev_offline()), and there's nothing to do
1876 	 * for the suspend because it's already suspended, or there's no ZIL.
1877 	 */
1878 	if (cookiep == NULL && !zilog->zl_suspending &&
1879 	    (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) {
1880 		mutex_exit(&zilog->zl_lock);
1881 		dmu_objset_rele(os, suspend_tag);
1882 		return (0);
1883 	}
1884 
1885 	dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag);
1886 	dsl_pool_rele(dmu_objset_pool(os), suspend_tag);
1887 
1888 	zilog->zl_suspend++;
1889 
1890 	if (zilog->zl_suspend > 1) {
1891 		/*
1892 		 * Someone else is already suspending it.
1893 		 * Just wait for them to finish.
1894 		 */
1895 
1896 		while (zilog->zl_suspending)
1897 			cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock);
1898 		mutex_exit(&zilog->zl_lock);
1899 
1900 		if (cookiep == NULL)
1901 			zil_resume(os);
1902 		else
1903 			*cookiep = os;
1904 		return (0);
1905 	}
1906 
1907 	/*
1908 	 * If there is no pointer to an on-disk block, this ZIL must not
1909 	 * be active (e.g. filesystem not mounted), so there's nothing
1910 	 * to clean up.
1911 	 */
1912 	if (BP_IS_HOLE(&zh->zh_log)) {
1913 		ASSERT(cookiep != NULL); /* fast path already handled */
1914 
1915 		*cookiep = os;
1916 		mutex_exit(&zilog->zl_lock);
1917 		return (0);
1918 	}
1919 
1920 	zilog->zl_suspending = B_TRUE;
1921 	mutex_exit(&zilog->zl_lock);
1922 
1923 	zil_commit(zilog, 0);
1924 
1925 	zil_destroy(zilog, B_FALSE);
1926 
1927 	mutex_enter(&zilog->zl_lock);
1928 	zilog->zl_suspending = B_FALSE;
1929 	cv_broadcast(&zilog->zl_cv_suspend);
1930 	mutex_exit(&zilog->zl_lock);
1931 
1932 	if (cookiep == NULL)
1933 		zil_resume(os);
1934 	else
1935 		*cookiep = os;
1936 	return (0);
1937 }
1938 
1939 void
zil_resume(void * cookie)1940 zil_resume(void *cookie)
1941 {
1942 	objset_t *os = cookie;
1943 	zilog_t *zilog = dmu_objset_zil(os);
1944 
1945 	mutex_enter(&zilog->zl_lock);
1946 	ASSERT(zilog->zl_suspend != 0);
1947 	zilog->zl_suspend--;
1948 	mutex_exit(&zilog->zl_lock);
1949 	dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
1950 	dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
1951 }
1952 
1953 typedef struct zil_replay_arg {
1954 	zil_replay_func_t **zr_replay;
1955 	void		*zr_arg;
1956 	boolean_t	zr_byteswap;
1957 	char		*zr_lr;
1958 } zil_replay_arg_t;
1959 
1960 static int
zil_replay_error(zilog_t * zilog,lr_t * lr,int error)1961 zil_replay_error(zilog_t *zilog, lr_t *lr, int error)
1962 {
1963 	char name[ZFS_MAX_DATASET_NAME_LEN];
1964 
1965 	zilog->zl_replaying_seq--;	/* didn't actually replay this one */
1966 
1967 	dmu_objset_name(zilog->zl_os, name);
1968 
1969 	cmn_err(CE_WARN, "ZFS replay transaction error %d, "
1970 	    "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name,
1971 	    (u_longlong_t)lr->lrc_seq,
1972 	    (u_longlong_t)(lr->lrc_txtype & ~TX_CI),
1973 	    (lr->lrc_txtype & TX_CI) ? "CI" : "");
1974 
1975 	return (error);
1976 }
1977 
1978 static int
zil_replay_log_record(zilog_t * zilog,lr_t * lr,void * zra,uint64_t claim_txg)1979 zil_replay_log_record(zilog_t *zilog, lr_t *lr, void *zra, uint64_t claim_txg)
1980 {
1981 	zil_replay_arg_t *zr = zra;
1982 	const zil_header_t *zh = zilog->zl_header;
1983 	uint64_t reclen = lr->lrc_reclen;
1984 	uint64_t txtype = lr->lrc_txtype;
1985 	int error = 0;
1986 
1987 	zilog->zl_replaying_seq = lr->lrc_seq;
1988 
1989 	if (lr->lrc_seq <= zh->zh_replay_seq)	/* already replayed */
1990 		return (0);
1991 
1992 	if (lr->lrc_txg < claim_txg)		/* already committed */
1993 		return (0);
1994 
1995 	/* Strip case-insensitive bit, still present in log record */
1996 	txtype &= ~TX_CI;
1997 
1998 	if (txtype == 0 || txtype >= TX_MAX_TYPE)
1999 		return (zil_replay_error(zilog, lr, EINVAL));
2000 
2001 	/*
2002 	 * If this record type can be logged out of order, the object
2003 	 * (lr_foid) may no longer exist.  That's legitimate, not an error.
2004 	 */
2005 	if (TX_OOO(txtype)) {
2006 		error = dmu_object_info(zilog->zl_os,
2007 		    ((lr_ooo_t *)lr)->lr_foid, NULL);
2008 		if (error == ENOENT || error == EEXIST)
2009 			return (0);
2010 	}
2011 
2012 	/*
2013 	 * Make a copy of the data so we can revise and extend it.
2014 	 */
2015 	bcopy(lr, zr->zr_lr, reclen);
2016 
2017 	/*
2018 	 * If this is a TX_WRITE with a blkptr, suck in the data.
2019 	 */
2020 	if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) {
2021 		error = zil_read_log_data(zilog, (lr_write_t *)lr,
2022 		    zr->zr_lr + reclen);
2023 		if (error != 0)
2024 			return (zil_replay_error(zilog, lr, error));
2025 	}
2026 
2027 	/*
2028 	 * The log block containing this lr may have been byteswapped
2029 	 * so that we can easily examine common fields like lrc_txtype.
2030 	 * However, the log is a mix of different record types, and only the
2031 	 * replay vectors know how to byteswap their records.  Therefore, if
2032 	 * the lr was byteswapped, undo it before invoking the replay vector.
2033 	 */
2034 	if (zr->zr_byteswap)
2035 		byteswap_uint64_array(zr->zr_lr, reclen);
2036 
2037 	/*
2038 	 * We must now do two things atomically: replay this log record,
2039 	 * and update the log header sequence number to reflect the fact that
2040 	 * we did so. At the end of each replay function the sequence number
2041 	 * is updated if we are in replay mode.
2042 	 */
2043 	error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap);
2044 	if (error != 0) {
2045 		/*
2046 		 * The DMU's dnode layer doesn't see removes until the txg
2047 		 * commits, so a subsequent claim can spuriously fail with
2048 		 * EEXIST. So if we receive any error we try syncing out
2049 		 * any removes then retry the transaction.  Note that we
2050 		 * specify B_FALSE for byteswap now, so we don't do it twice.
2051 		 */
2052 		txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0);
2053 		error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE);
2054 		if (error != 0)
2055 			return (zil_replay_error(zilog, lr, error));
2056 	}
2057 	return (0);
2058 }
2059 
2060 /* ARGSUSED */
2061 static int
zil_incr_blks(zilog_t * zilog,blkptr_t * bp,void * arg,uint64_t claim_txg)2062 zil_incr_blks(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
2063 {
2064 	zilog->zl_replay_blks++;
2065 
2066 	return (0);
2067 }
2068 
2069 /*
2070  * If this dataset has a non-empty intent log, replay it and destroy it.
2071  */
2072 void
zil_replay(objset_t * os,void * arg,zil_replay_func_t * replay_func[TX_MAX_TYPE])2073 zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE])
2074 {
2075 	zilog_t *zilog = dmu_objset_zil(os);
2076 	const zil_header_t *zh = zilog->zl_header;
2077 	zil_replay_arg_t zr;
2078 
2079 	if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
2080 		zil_destroy(zilog, B_TRUE);
2081 		return;
2082 	}
2083 
2084 	zr.zr_replay = replay_func;
2085 	zr.zr_arg = arg;
2086 	zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log);
2087 	zr.zr_lr = kmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP);
2088 
2089 	/*
2090 	 * Wait for in-progress removes to sync before starting replay.
2091 	 */
2092 	txg_wait_synced(zilog->zl_dmu_pool, 0);
2093 
2094 	zilog->zl_replay = B_TRUE;
2095 	zilog->zl_replay_time = ddi_get_lbolt();
2096 	ASSERT(zilog->zl_replay_blks == 0);
2097 	(void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr,
2098 	    zh->zh_claim_txg);
2099 	kmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE);
2100 
2101 	zil_destroy(zilog, B_FALSE);
2102 	txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
2103 	zilog->zl_replay = B_FALSE;
2104 }
2105 
2106 boolean_t
zil_replaying(zilog_t * zilog,dmu_tx_t * tx)2107 zil_replaying(zilog_t *zilog, dmu_tx_t *tx)
2108 {
2109 	if (zilog->zl_sync == ZFS_SYNC_DISABLED)
2110 		return (B_TRUE);
2111 
2112 	if (zilog->zl_replay) {
2113 		dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
2114 		zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] =
2115 		    zilog->zl_replaying_seq;
2116 		return (B_TRUE);
2117 	}
2118 
2119 	return (B_FALSE);
2120 }
2121 
2122 /* ARGSUSED */
2123 int
zil_vdev_offline(const char * osname,void * arg)2124 zil_vdev_offline(const char *osname, void *arg)
2125 {
2126 	int error;
2127 
2128 	error = zil_suspend(osname, NULL);
2129 	if (error != 0)
2130 		return (SET_ERROR(EEXIST));
2131 	return (0);
2132 }
2133