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