xref: /titanic_41/usr/src/uts/common/fs/zfs/dmu_traverse.c (revision b509e89b2befbaa42939abad9da1d7f5a8c6aaae)
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 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/zfs_context.h>
27 #include <sys/dmu_objset.h>
28 #include <sys/dmu_traverse.h>
29 #include <sys/dsl_dataset.h>
30 #include <sys/dsl_dir.h>
31 #include <sys/dsl_pool.h>
32 #include <sys/dnode.h>
33 #include <sys/spa.h>
34 #include <sys/zio.h>
35 #include <sys/dmu_impl.h>
36 #include <sys/callb.h>
37 
38 #define	SET_BOOKMARK(zb, objset, object, level, blkid)  \
39 {                                                       \
40 	(zb)->zb_objset = objset;                       \
41 	(zb)->zb_object = object;                       \
42 	(zb)->zb_level = level;                         \
43 	(zb)->zb_blkid = blkid;                         \
44 }
45 
46 struct prefetch_data {
47 	kmutex_t pd_mtx;
48 	kcondvar_t pd_cv;
49 	int pd_blks_max;
50 	int pd_blks_fetched;
51 	int pd_flags;
52 	boolean_t pd_cancel;
53 	boolean_t pd_exited;
54 };
55 
56 struct traverse_data {
57 	spa_t *td_spa;
58 	uint64_t td_objset;
59 	blkptr_t *td_rootbp;
60 	uint64_t td_min_txg;
61 	int td_flags;
62 	struct prefetch_data *td_pfd;
63 	blkptr_cb_t *td_func;
64 	void *td_arg;
65 };
66 
67 static int traverse_dnode(struct traverse_data *td, const dnode_phys_t *dnp,
68     arc_buf_t *buf, uint64_t objset, uint64_t object);
69 
70 /* ARGSUSED */
71 static void
72 traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
73 {
74 	struct traverse_data *td = arg;
75 	zbookmark_t zb;
76 
77 	if (bp->blk_birth == 0)
78 		return;
79 
80 	if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(td->td_spa))
81 		return;
82 
83 	zb.zb_objset = td->td_objset;
84 	zb.zb_object = 0;
85 	zb.zb_level = -1;
86 	zb.zb_blkid = bp->blk_cksum.zc_word[ZIL_ZC_SEQ];
87 	VERIFY(0 == td->td_func(td->td_spa, bp, &zb, NULL, td->td_arg));
88 }
89 
90 /* ARGSUSED */
91 static void
92 traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
93 {
94 	struct traverse_data *td = arg;
95 
96 	if (lrc->lrc_txtype == TX_WRITE) {
97 		lr_write_t *lr = (lr_write_t *)lrc;
98 		blkptr_t *bp = &lr->lr_blkptr;
99 		zbookmark_t zb;
100 
101 		if (bp->blk_birth == 0)
102 			return;
103 
104 		if (claim_txg == 0 || bp->blk_birth < claim_txg)
105 			return;
106 
107 		zb.zb_objset = td->td_objset;
108 		zb.zb_object = lr->lr_foid;
109 		zb.zb_level = BP_GET_LEVEL(bp);
110 		zb.zb_blkid = lr->lr_offset / BP_GET_LSIZE(bp);
111 		VERIFY(0 == td->td_func(td->td_spa, bp, &zb, NULL, td->td_arg));
112 	}
113 }
114 
115 static void
116 traverse_zil(struct traverse_data *td, zil_header_t *zh)
117 {
118 	uint64_t claim_txg = zh->zh_claim_txg;
119 	zilog_t *zilog;
120 
121 	/*
122 	 * We only want to visit blocks that have been claimed but not yet
123 	 * replayed (or, in read-only mode, blocks that *would* be claimed).
124 	 */
125 	if (claim_txg == 0 && spa_writeable(td->td_spa))
126 		return;
127 
128 	zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
129 
130 	(void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
131 	    claim_txg);
132 
133 	zil_free(zilog);
134 }
135 
136 static int
137 traverse_visitbp(struct traverse_data *td, const dnode_phys_t *dnp,
138     arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb)
139 {
140 	zbookmark_t czb;
141 	int err = 0;
142 	arc_buf_t *buf = NULL;
143 	struct prefetch_data *pd = td->td_pfd;
144 
145 	if (bp->blk_birth == 0) {
146 		err = td->td_func(td->td_spa, NULL, zb, dnp, td->td_arg);
147 		return (err);
148 	}
149 
150 	if (bp->blk_birth <= td->td_min_txg)
151 		return (0);
152 
153 	if (pd && !pd->pd_exited &&
154 	    ((pd->pd_flags & TRAVERSE_PREFETCH_DATA) ||
155 	    BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0)) {
156 		mutex_enter(&pd->pd_mtx);
157 		ASSERT(pd->pd_blks_fetched >= 0);
158 		while (pd->pd_blks_fetched == 0 && !pd->pd_exited)
159 			cv_wait(&pd->pd_cv, &pd->pd_mtx);
160 		pd->pd_blks_fetched--;
161 		cv_broadcast(&pd->pd_cv);
162 		mutex_exit(&pd->pd_mtx);
163 	}
164 
165 	if (td->td_flags & TRAVERSE_PRE) {
166 		err = td->td_func(td->td_spa, bp, zb, dnp, td->td_arg);
167 		if (err)
168 			return (err);
169 	}
170 
171 	if (BP_GET_LEVEL(bp) > 0) {
172 		uint32_t flags = ARC_WAIT;
173 		int i;
174 		blkptr_t *cbp;
175 		int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
176 
177 		err = arc_read(NULL, td->td_spa, bp, pbuf,
178 		    arc_getbuf_func, &buf,
179 		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
180 		if (err)
181 			return (err);
182 
183 		/* recursively visitbp() blocks below this */
184 		cbp = buf->b_data;
185 		for (i = 0; i < epb; i++, cbp++) {
186 			SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
187 			    zb->zb_level - 1,
188 			    zb->zb_blkid * epb + i);
189 			err = traverse_visitbp(td, dnp, buf, cbp, &czb);
190 			if (err)
191 				break;
192 		}
193 	} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
194 		uint32_t flags = ARC_WAIT;
195 		int i;
196 		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
197 
198 		err = arc_read(NULL, td->td_spa, bp, pbuf,
199 		    arc_getbuf_func, &buf,
200 		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
201 		if (err)
202 			return (err);
203 
204 		/* recursively visitbp() blocks below this */
205 		dnp = buf->b_data;
206 		for (i = 0; i < epb && err == 0; i++, dnp++) {
207 			err = traverse_dnode(td, dnp, buf, zb->zb_objset,
208 			    zb->zb_blkid * epb + i);
209 			if (err)
210 				break;
211 		}
212 	} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
213 		uint32_t flags = ARC_WAIT;
214 		objset_phys_t *osp;
215 		dnode_phys_t *dnp;
216 
217 		err = arc_read_nolock(NULL, td->td_spa, bp,
218 		    arc_getbuf_func, &buf,
219 		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
220 		if (err)
221 			return (err);
222 
223 		osp = buf->b_data;
224 		traverse_zil(td, &osp->os_zil_header);
225 
226 		dnp = &osp->os_meta_dnode;
227 		err = traverse_dnode(td, dnp, buf, zb->zb_objset, 0);
228 		if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
229 			dnp = &osp->os_userused_dnode;
230 			err = traverse_dnode(td, dnp, buf, zb->zb_objset,
231 			    DMU_USERUSED_OBJECT);
232 		}
233 		if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
234 			dnp = &osp->os_groupused_dnode;
235 			err = traverse_dnode(td, dnp, buf, zb->zb_objset,
236 			    DMU_GROUPUSED_OBJECT);
237 		}
238 	}
239 
240 	if (buf)
241 		(void) arc_buf_remove_ref(buf, &buf);
242 
243 	if (err == 0 && (td->td_flags & TRAVERSE_POST))
244 		err = td->td_func(td->td_spa, bp, zb, dnp, td->td_arg);
245 
246 	return (err);
247 }
248 
249 static int
250 traverse_dnode(struct traverse_data *td, const dnode_phys_t *dnp,
251     arc_buf_t *buf, uint64_t objset, uint64_t object)
252 {
253 	int j, err = 0;
254 	zbookmark_t czb;
255 
256 	for (j = 0; j < dnp->dn_nblkptr; j++) {
257 		SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
258 		err = traverse_visitbp(td, dnp, buf,
259 		    (blkptr_t *)&dnp->dn_blkptr[j], &czb);
260 		if (err)
261 			break;
262 	}
263 	return (err);
264 }
265 
266 /* ARGSUSED */
267 static int
268 traverse_prefetcher(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
269     const dnode_phys_t *dnp, void *arg)
270 {
271 	struct prefetch_data *pfd = arg;
272 	uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
273 
274 	ASSERT(pfd->pd_blks_fetched >= 0);
275 	if (pfd->pd_cancel)
276 		return (EINTR);
277 
278 	if (bp == NULL || !((pfd->pd_flags & TRAVERSE_PREFETCH_DATA) ||
279 	    BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0))
280 		return (0);
281 
282 	mutex_enter(&pfd->pd_mtx);
283 	while (!pfd->pd_cancel && pfd->pd_blks_fetched >= pfd->pd_blks_max)
284 		cv_wait(&pfd->pd_cv, &pfd->pd_mtx);
285 	pfd->pd_blks_fetched++;
286 	cv_broadcast(&pfd->pd_cv);
287 	mutex_exit(&pfd->pd_mtx);
288 
289 	(void) arc_read_nolock(NULL, spa, bp, NULL, NULL,
290 	    ZIO_PRIORITY_ASYNC_READ,
291 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
292 	    &aflags, zb);
293 
294 	return (0);
295 }
296 
297 static void
298 traverse_prefetch_thread(void *arg)
299 {
300 	struct traverse_data *td_main = arg;
301 	struct traverse_data td = *td_main;
302 	zbookmark_t czb;
303 
304 	td.td_func = traverse_prefetcher;
305 	td.td_arg = td_main->td_pfd;
306 	td.td_pfd = NULL;
307 
308 	SET_BOOKMARK(&czb, td.td_objset, 0, -1, 0);
309 	(void) traverse_visitbp(&td, NULL, NULL, td.td_rootbp, &czb);
310 
311 	mutex_enter(&td_main->td_pfd->pd_mtx);
312 	td_main->td_pfd->pd_exited = B_TRUE;
313 	cv_broadcast(&td_main->td_pfd->pd_cv);
314 	mutex_exit(&td_main->td_pfd->pd_mtx);
315 }
316 
317 /*
318  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
319  * in syncing context).
320  */
321 static int
322 traverse_impl(spa_t *spa, uint64_t objset, blkptr_t *rootbp,
323     uint64_t txg_start, int flags, blkptr_cb_t func, void *arg)
324 {
325 	struct traverse_data td;
326 	struct prefetch_data pd = { 0 };
327 	zbookmark_t czb;
328 	int err;
329 
330 	td.td_spa = spa;
331 	td.td_objset = objset;
332 	td.td_rootbp = rootbp;
333 	td.td_min_txg = txg_start;
334 	td.td_func = func;
335 	td.td_arg = arg;
336 	td.td_pfd = &pd;
337 	td.td_flags = flags;
338 
339 	pd.pd_blks_max = 100;
340 	pd.pd_flags = flags;
341 	mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);
342 	cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);
343 
344 	if (!(flags & TRAVERSE_PREFETCH) ||
345 	    0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,
346 	    &td, TQ_NOQUEUE))
347 		pd.pd_exited = B_TRUE;
348 
349 	SET_BOOKMARK(&czb, objset, 0, -1, 0);
350 	err = traverse_visitbp(&td, NULL, NULL, rootbp, &czb);
351 
352 	mutex_enter(&pd.pd_mtx);
353 	pd.pd_cancel = B_TRUE;
354 	cv_broadcast(&pd.pd_cv);
355 	while (!pd.pd_exited)
356 		cv_wait(&pd.pd_cv, &pd.pd_mtx);
357 	mutex_exit(&pd.pd_mtx);
358 
359 	mutex_destroy(&pd.pd_mtx);
360 	cv_destroy(&pd.pd_cv);
361 
362 	return (err);
363 }
364 
365 /*
366  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
367  * in syncing context).
368  */
369 int
370 traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start, int flags,
371     blkptr_cb_t func, void *arg)
372 {
373 	return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds->ds_object,
374 	    &ds->ds_phys->ds_bp, txg_start, flags, func, arg));
375 }
376 
377 /*
378  * NB: pool must not be changing on-disk (eg, from zdb or sync context).
379  */
380 int
381 traverse_pool(spa_t *spa, blkptr_cb_t func, void *arg)
382 {
383 	int err;
384 	uint64_t obj;
385 	dsl_pool_t *dp = spa_get_dsl(spa);
386 	objset_t *mos = dp->dp_meta_objset;
387 
388 	/* visit the MOS */
389 	err = traverse_impl(spa, 0, spa_get_rootblkptr(spa),
390 	    0, TRAVERSE_PRE, func, arg);
391 	if (err)
392 		return (err);
393 
394 	/* visit each dataset */
395 	for (obj = 1; err == 0; err = dmu_object_next(mos, &obj, FALSE, 0)) {
396 		dmu_object_info_t doi;
397 
398 		err = dmu_object_info(mos, obj, &doi);
399 		if (err)
400 			return (err);
401 
402 		if (doi.doi_type == DMU_OT_DSL_DATASET) {
403 			dsl_dataset_t *ds;
404 			rw_enter(&dp->dp_config_rwlock, RW_READER);
405 			err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
406 			rw_exit(&dp->dp_config_rwlock);
407 			if (err)
408 				return (err);
409 			err = traverse_dataset(ds,
410 			    ds->ds_phys->ds_prev_snap_txg, TRAVERSE_PRE,
411 			    func, arg);
412 			dsl_dataset_rele(ds, FTAG);
413 			if (err)
414 				return (err);
415 		}
416 	}
417 	if (err == ESRCH)
418 		err = 0;
419 	return (err);
420 }
421