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 /*
23 * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
24 * Copyright (c) 2014 Integros [integros.com]
25 */
26
27 #include <sys/arc.h>
28 #include <sys/bptree.h>
29 #include <sys/dmu.h>
30 #include <sys/dmu_objset.h>
31 #include <sys/dmu_tx.h>
32 #include <sys/dmu_traverse.h>
33 #include <sys/dsl_dataset.h>
34 #include <sys/dsl_dir.h>
35 #include <sys/dsl_pool.h>
36 #include <sys/dnode.h>
37 #include <sys/refcount.h>
38 #include <sys/spa.h>
39
40 /*
41 * A bptree is a queue of root block pointers from destroyed datasets. When a
42 * dataset is destroyed its root block pointer is put on the end of the pool's
43 * bptree queue so the dataset's blocks can be freed asynchronously by
44 * dsl_scan_sync. This allows the delete operation to finish without traversing
45 * all the dataset's blocks.
46 *
47 * Note that while bt_begin and bt_end are only ever incremented in this code,
48 * they are effectively reset to 0 every time the entire bptree is freed because
49 * the bptree's object is destroyed and re-created.
50 */
51
52 struct bptree_args {
53 bptree_phys_t *ba_phys; /* data in bonus buffer, dirtied if freeing */
54 boolean_t ba_free; /* true if freeing during traversal */
55
56 bptree_itor_t *ba_func; /* function to call for each blockpointer */
57 void *ba_arg; /* caller supplied argument to ba_func */
58 dmu_tx_t *ba_tx; /* caller supplied tx, NULL if not freeing */
59 } bptree_args_t;
60
61 uint64_t
62 bptree_alloc(objset_t *os, dmu_tx_t *tx)
63 {
64 uint64_t obj;
65 dmu_buf_t *db;
66 bptree_phys_t *bt;
67
68 obj = dmu_object_alloc(os, DMU_OTN_UINT64_METADATA,
69 SPA_OLD_MAXBLOCKSIZE, DMU_OTN_UINT64_METADATA,
70 sizeof (bptree_phys_t), tx);
71
72 /*
73 * Bonus buffer contents are already initialized to 0, but for
74 * readability we make it explicit.
75 */
76 VERIFY3U(0, ==, dmu_bonus_hold(os, obj, FTAG, &db));
77 dmu_buf_will_dirty(db, tx);
78 bt = db->db_data;
79 bt->bt_begin = 0;
80 bt->bt_end = 0;
81 bt->bt_bytes = 0;
82 bt->bt_comp = 0;
83 bt->bt_uncomp = 0;
84 dmu_buf_rele(db, FTAG);
85
86 return (obj);
87 }
88
89 int
90 bptree_free(objset_t *os, uint64_t obj, dmu_tx_t *tx)
91 {
92 dmu_buf_t *db;
93 bptree_phys_t *bt;
94
95 VERIFY3U(0, ==, dmu_bonus_hold(os, obj, FTAG, &db));
96 bt = db->db_data;
97 ASSERT3U(bt->bt_begin, ==, bt->bt_end);
98 ASSERT0(bt->bt_bytes);
99 ASSERT0(bt->bt_comp);
100 ASSERT0(bt->bt_uncomp);
101 dmu_buf_rele(db, FTAG);
102
103 return (dmu_object_free(os, obj, tx));
104 }
105
106 boolean_t
107 bptree_is_empty(objset_t *os, uint64_t obj)
108 {
109 dmu_buf_t *db;
110 bptree_phys_t *bt;
111 boolean_t rv;
112
113 VERIFY0(dmu_bonus_hold(os, obj, FTAG, &db));
114 bt = db->db_data;
115 rv = (bt->bt_begin == bt->bt_end);
116 dmu_buf_rele(db, FTAG);
117 return (rv);
118 }
119
120 void
121 bptree_add(objset_t *os, uint64_t obj, blkptr_t *bp, uint64_t birth_txg,
122 uint64_t bytes, uint64_t comp, uint64_t uncomp, dmu_tx_t *tx)
123 {
124 dmu_buf_t *db;
125 bptree_phys_t *bt;
126 bptree_entry_phys_t bte = { .be_birth_txg = 0 };
127
128 /*
129 * bptree objects are in the pool mos, therefore they can only be
130 * modified in syncing context. Furthermore, this is only modified
131 * by the sync thread, so no locking is necessary.
132 */
133 ASSERT(dmu_tx_is_syncing(tx));
134
135 VERIFY3U(0, ==, dmu_bonus_hold(os, obj, FTAG, &db));
136 bt = db->db_data;
137
138 bte.be_birth_txg = birth_txg;
139 bte.be_bp = *bp;
140 dmu_write(os, obj, bt->bt_end * sizeof (bte), sizeof (bte), &bte, tx);
141
142 dmu_buf_will_dirty(db, tx);
143 bt->bt_end++;
144 bt->bt_bytes += bytes;
145 bt->bt_comp += comp;
146 bt->bt_uncomp += uncomp;
147 dmu_buf_rele(db, FTAG);
148 }
149
150 /* ARGSUSED */
151 static int
152 bptree_visit_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
153 const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
154 {
155 int err;
156 struct bptree_args *ba = arg;
157
158 if (bp == NULL || BP_IS_HOLE(bp))
159 return (0);
160
161 err = ba->ba_func(ba->ba_arg, bp, ba->ba_tx);
162 if (err == 0 && ba->ba_free) {
163 ba->ba_phys->bt_bytes -= bp_get_dsize_sync(spa, bp);
164 ba->ba_phys->bt_comp -= BP_GET_PSIZE(bp);
165 ba->ba_phys->bt_uncomp -= BP_GET_UCSIZE(bp);
166 }
167 return (err);
168 }
169
170 /*
171 * If "free" is set:
172 * - It is assumed that "func" will be freeing the block pointers.
173 * - If "func" returns nonzero, the bookmark will be remembered and
174 * iteration will be restarted from this point on next invocation.
175 * - If an i/o error is encountered (e.g. "func" returns EIO or ECKSUM),
176 * bptree_iterate will remember the bookmark, continue traversing
177 * any additional entries, and return 0.
178 *
179 * If "free" is not set, traversal will stop and return an error if
180 * an i/o error is encountered.
181 *
182 * In either case, if zfs_free_leak_on_eio is set, i/o errors will be
183 * ignored and traversal will continue (i.e. TRAVERSE_HARD will be passed to
184 * traverse_dataset_destroyed()).
185 */
186 int
187 bptree_iterate(objset_t *os, uint64_t obj, boolean_t free, bptree_itor_t func,
188 void *arg, dmu_tx_t *tx)
189 {
190 boolean_t ioerr = B_FALSE;
191 int err;
192 uint64_t i;
193 dmu_buf_t *db;
194 struct bptree_args ba;
195
196 ASSERT(!free || dmu_tx_is_syncing(tx));
197
198 err = dmu_bonus_hold(os, obj, FTAG, &db);
199 if (err != 0)
200 return (err);
201
202 if (free)
203 dmu_buf_will_dirty(db, tx);
204
205 ba.ba_phys = db->db_data;
206 ba.ba_free = free;
207 ba.ba_func = func;
208 ba.ba_arg = arg;
209 ba.ba_tx = tx;
210
211 err = 0;
212 for (i = ba.ba_phys->bt_begin; i < ba.ba_phys->bt_end; i++) {
213 bptree_entry_phys_t bte;
214 int flags = TRAVERSE_PREFETCH_METADATA | TRAVERSE_POST;
215
216 err = dmu_read(os, obj, i * sizeof (bte), sizeof (bte),
217 &bte, DMU_READ_NO_PREFETCH);
218 if (err != 0)
219 break;
220
221 if (zfs_free_leak_on_eio)
222 flags |= TRAVERSE_HARD;
223 zfs_dbgmsg("bptree index %lld: traversing from min_txg=%lld "
224 "bookmark %lld/%lld/%lld/%lld",
225 (longlong_t)i,
226 (longlong_t)bte.be_birth_txg,
227 (longlong_t)bte.be_zb.zb_objset,
228 (longlong_t)bte.be_zb.zb_object,
229 (longlong_t)bte.be_zb.zb_level,
230 (longlong_t)bte.be_zb.zb_blkid);
231 err = traverse_dataset_destroyed(os->os_spa, &bte.be_bp,
232 bte.be_birth_txg, &bte.be_zb, flags,
233 bptree_visit_cb, &ba);
234 if (free) {
235 /*
236 * The callback has freed the visited block pointers.
237 * Record our traversal progress on disk, either by
238 * updating this record's bookmark, or by logically
239 * removing this record by advancing bt_begin.
240 */
241 if (err != 0) {
242 /* save bookmark for future resume */
243 ASSERT3U(bte.be_zb.zb_objset, ==,
244 ZB_DESTROYED_OBJSET);
245 ASSERT0(bte.be_zb.zb_level);
246 dmu_write(os, obj, i * sizeof (bte),
247 sizeof (bte), &bte, tx);
248 if (err == EIO || err == ECKSUM ||
249 err == ENXIO) {
250 /*
251 * Skip the rest of this tree and
252 * continue on to the next entry.
253 */
254 err = 0;
255 ioerr = B_TRUE;
256 } else {
257 break;
258 }
259 } else if (ioerr) {
260 /*
261 * This entry is finished, but there were
262 * i/o errors on previous entries, so we
263 * can't adjust bt_begin. Set this entry's
264 * be_birth_txg such that it will be
265 * treated as a no-op in future traversals.
266 */
267 bte.be_birth_txg = UINT64_MAX;
268 dmu_write(os, obj, i * sizeof (bte),
269 sizeof (bte), &bte, tx);
270 }
271
272 if (!ioerr) {
273 ba.ba_phys->bt_begin++;
274 (void) dmu_free_range(os, obj,
275 i * sizeof (bte), sizeof (bte), tx);
276 }
277 } else if (err != 0) {
278 break;
279 }
280 }
281
282 ASSERT(!free || err != 0 || ioerr ||
283 ba.ba_phys->bt_begin == ba.ba_phys->bt_end);
284
285 /* if all blocks are free there should be no used space */
286 if (ba.ba_phys->bt_begin == ba.ba_phys->bt_end) {
287 if (zfs_free_leak_on_eio) {
288 ba.ba_phys->bt_bytes = 0;
289 ba.ba_phys->bt_comp = 0;
290 ba.ba_phys->bt_uncomp = 0;
291 }
292
293 ASSERT0(ba.ba_phys->bt_bytes);
294 ASSERT0(ba.ba_phys->bt_comp);
295 ASSERT0(ba.ba_phys->bt_uncomp);
296 }
297
298 dmu_buf_rele(db, FTAG);
299
300 return (err);
301 }