module/zfs/dmu_traverse.c

   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 2008 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 /* ARGSUSED */
  68 static void
  69 traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
  70 {
  71         struct traverse_data *td = arg;
  72         zbookmark_t zb;
  73
  74         if (bp->blk_birth == 0)
  75                 return;
  76
  77         if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(td->td_spa))
  78                 return;
  79
  80         zb.zb_objset = td->td_objset;
  81         zb.zb_object = 0;
  82         zb.zb_level = -1;
  83         zb.zb_blkid = bp->blk_cksum.zc_word[ZIL_ZC_SEQ];
  84         VERIFY(0 == td->td_func(td->td_spa, bp, &zb, NULL, td->td_arg));
  85 }
  86
  87 /* ARGSUSED */
  88 static void
  89 traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
  90 {
  91         struct traverse_data *td = arg;
  92
  93         if (lrc->lrc_txtype == TX_WRITE) {
  94                 lr_write_t *lr = (lr_write_t *)lrc;
  95                 blkptr_t *bp = &lr->lr_blkptr;
  96                 zbookmark_t zb;
  97
  98                 if (bp->blk_birth == 0)
  99                         return;
 100
 101                 if (claim_txg == 0 || bp->blk_birth < claim_txg)
 102                         return;
 103
 104                 zb.zb_objset = td->td_objset;
 105                 zb.zb_object = lr->lr_foid;
 106                 zb.zb_level = BP_GET_LEVEL(bp);
 107                 zb.zb_blkid = lr->lr_offset / BP_GET_LSIZE(bp);
 108                 VERIFY(0 == td->td_func(td->td_spa, bp, &zb, NULL, td->td_arg));
 109         }
 110 }
 111
 112 static void
 113 traverse_zil(struct traverse_data *td, zil_header_t *zh)
 114 {
 115         uint64_t claim_txg = zh->zh_claim_txg;
 116         zilog_t *zilog;
 117
 118         /*
 119          * We only want to visit blocks that have been claimed but not yet
 120          * replayed (or, in read-only mode, blocks that *would* be claimed).
 121          */
 122         if (claim_txg == 0 && spa_writeable(td->td_spa))
 123                 return;
 124
 125         zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
 126
 127         (void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
 128             claim_txg);
 129
 130         zil_free(zilog);
 131 }
 132
 133 static int
 134 traverse_visitbp(struct traverse_data *td, const dnode_phys_t *dnp,
 135     arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb)
 136 {
 137         zbookmark_t czb;
 138         int err = 0;
 139         arc_buf_t *buf = NULL;
 140         struct prefetch_data *pd = td->td_pfd;
 141
 142         if (bp->blk_birth == 0) {
 143                 err = td->td_func(td->td_spa, NULL, zb, dnp, td->td_arg);
 144                 return (err);
 145         }
 146
 147         if (bp->blk_birth <= td->td_min_txg)
 148                 return (0);
 149
 150         if (pd && !pd->pd_exited &&
 151             ((pd->pd_flags & TRAVERSE_PREFETCH_DATA) ||
 152             BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0)) {
 153                 mutex_enter(&pd->pd_mtx);
 154                 ASSERT(pd->pd_blks_fetched >= 0);
 155                 while (pd->pd_blks_fetched == 0 && !pd->pd_exited)
 156                         cv_wait(&pd->pd_cv, &pd->pd_mtx);
 157                 pd->pd_blks_fetched--;
 158                 cv_broadcast(&pd->pd_cv);
 159                 mutex_exit(&pd->pd_mtx);
 160         }
 161
 162         if (td->td_flags & TRAVERSE_PRE) {
 163                 err = td->td_func(td->td_spa, bp, zb, dnp, td->td_arg);
 164                 if (err)
 165                         return (err);
 166         }
 167
 168         if (BP_GET_LEVEL(bp) > 0) {
 169                 uint32_t flags = ARC_WAIT;
 170                 int i;
 171                 blkptr_t *cbp;
 172                 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
 173
 174                 err = arc_read(NULL, td->td_spa, bp, pbuf,
 175                     arc_getbuf_func, &buf,
 176                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 177                 if (err)
 178                         return (err);
 179
 180                 /* recursively visitbp() blocks below this */
 181                 cbp = buf->b_data;
 182                 for (i = 0; i < epb; i++, cbp++) {
 183                         SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
 184                             zb->zb_level - 1,
 185                             zb->zb_blkid * epb + i);
 186                         err = traverse_visitbp(td, dnp, buf, cbp, &czb);
 187                         if (err)
 188                                 break;
 189                 }
 190         } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
 191                 uint32_t flags = ARC_WAIT;
 192                 int i, j;
 193                 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 194
 195                 err = arc_read(NULL, td->td_spa, bp, pbuf,
 196                     arc_getbuf_func, &buf,
 197                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 198                 if (err)
 199                         return (err);
 200
 201                 /* recursively visitbp() blocks below this */
 202                 dnp = buf->b_data;
 203                 for (i = 0; i < epb && err == 0; i++, dnp++) {
 204                         for (j = 0; j < dnp->dn_nblkptr; j++) {
 205                                 SET_BOOKMARK(&czb, zb->zb_objset,
 206                                     zb->zb_blkid * epb + i,
 207                                     dnp->dn_nlevels - 1, j);
 208                                 err = traverse_visitbp(td, dnp, buf,
 209                                     (blkptr_t *)&dnp->dn_blkptr[j], &czb);
 210                                 if (err)
 211                                         break;
 212                         }
 213                 }
 214         } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
 215                 uint32_t flags = ARC_WAIT;
 216                 objset_phys_t *osp;
 217                 int j;
 218
 219                 err = arc_read_nolock(NULL, td->td_spa, bp,
 220                     arc_getbuf_func, &buf,
 221                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 222                 if (err)
 223                         return (err);
 224
 225                 osp = buf->b_data;
 226                 /*
 227                  * traverse_zil is just here for zdb's leak checking.
 228                  * For other consumers, there will be no ZIL blocks.
 229                  */
 230                 traverse_zil(td, &osp->os_zil_header);
 231
 232                 for (j = 0; j < osp->os_meta_dnode.dn_nblkptr; j++) {
 233                         SET_BOOKMARK(&czb, zb->zb_objset, 0,
 234                             osp->os_meta_dnode.dn_nlevels - 1, j);
 235                         err = traverse_visitbp(td, &osp->os_meta_dnode, buf,
 236                             (blkptr_t *)&osp->os_meta_dnode.dn_blkptr[j],
 237                             &czb);
 238                         if (err)
 239                                 break;
 240                 }
 241         }
 242
 243         if (buf)
 244                 (void) arc_buf_remove_ref(buf, &buf);
 245
 246         if (err == 0 && (td->td_flags & TRAVERSE_POST))
 247                 err = td->td_func(td->td_spa, bp, zb, dnp, td->td_arg);
 248
 249         return (err);
 250 }
 251
 252 /* ARGSUSED */
 253 static int
 254 traverse_prefetcher(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
 255     const dnode_phys_t *dnp, void *arg)
 256 {
 257         struct prefetch_data *pfd = arg;
 258         uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
 259
 260         ASSERT(pfd->pd_blks_fetched >= 0);
 261         if (pfd->pd_cancel)
 262                 return (EINTR);
 263
 264         if (bp == NULL || !((pfd->pd_flags & TRAVERSE_PREFETCH_DATA) ||
 265             BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0))
 266                 return (0);
 267
 268         mutex_enter(&pfd->pd_mtx);
 269         while (!pfd->pd_cancel && pfd->pd_blks_fetched >= pfd->pd_blks_max)
 270                 cv_wait(&pfd->pd_cv, &pfd->pd_mtx);
 271         pfd->pd_blks_fetched++;
 272         cv_broadcast(&pfd->pd_cv);
 273         mutex_exit(&pfd->pd_mtx);
 274
 275         (void) arc_read_nolock(NULL, spa, bp, NULL, NULL,
 276             ZIO_PRIORITY_ASYNC_READ,
 277             ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
 278             &aflags, zb);
 279
 280         return (0);
 281 }
 282
 283 static void
 284 traverse_prefetch_thread(void *arg)
 285 {
 286         struct traverse_data *td_main = arg;
 287         struct traverse_data td = *td_main;
 288         zbookmark_t czb;
 289
 290         td.td_func = traverse_prefetcher;
 291         td.td_arg = td_main->td_pfd;
 292         td.td_pfd = NULL;
 293
 294         SET_BOOKMARK(&czb, td.td_objset, 0, -1, 0);
 295         (void) traverse_visitbp(&td, NULL, NULL, td.td_rootbp, &czb);
 296
 297         mutex_enter(&td_main->td_pfd->pd_mtx);
 298         td_main->td_pfd->pd_exited = B_TRUE;
 299         cv_broadcast(&td_main->td_pfd->pd_cv);
 300         mutex_exit(&td_main->td_pfd->pd_mtx);
 301 }
 302
 303 /*
 304  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
 305  * in syncing context).
 306  */
 307 static int
 308 traverse_impl(spa_t *spa, uint64_t objset, blkptr_t *rootbp,
 309     uint64_t txg_start, int flags, blkptr_cb_t func, void *arg)
 310 {
 311         struct traverse_data td;
 312         struct prefetch_data pd = { 0 };
 313         zbookmark_t czb;
 314         int err;
 315
 316         td.td_spa = spa;
 317         td.td_objset = objset;
 318         td.td_rootbp = rootbp;
 319         td.td_min_txg = txg_start;
 320         td.td_func = func;
 321         td.td_arg = arg;
 322         td.td_pfd = &pd;
 323         td.td_flags = flags;
 324
 325         pd.pd_blks_max = 100;
 326         pd.pd_flags = flags;
 327         mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);
 328         cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);
 329
 330         if (!(flags & TRAVERSE_PREFETCH) ||
 331             0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,
 332             &td, TQ_NOQUEUE))
 333                 pd.pd_exited = B_TRUE;
 334
 335         SET_BOOKMARK(&czb, objset, 0, -1, 0);
 336         err = traverse_visitbp(&td, NULL, NULL, rootbp, &czb);
 337
 338         mutex_enter(&pd.pd_mtx);
 339         pd.pd_cancel = B_TRUE;
 340         cv_broadcast(&pd.pd_cv);
 341         while (!pd.pd_exited)
 342                 cv_wait(&pd.pd_cv, &pd.pd_mtx);
 343         mutex_exit(&pd.pd_mtx);
 344
 345         mutex_destroy(&pd.pd_mtx);
 346         cv_destroy(&pd.pd_cv);
 347
 348         return (err);
 349 }
 350
 351 /*
 352  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
 353  * in syncing context).
 354  */
 355 int
 356 traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start, int flags,
 357     blkptr_cb_t func, void *arg)
 358 {
 359         return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds->ds_object,
 360             &ds->ds_phys->ds_bp, txg_start, flags, func, arg));
 361 }
 362
 363 /*
 364  * NB: pool must not be changing on-disk (eg, from zdb or sync context).
 365  */
 366 int
 367 traverse_pool(spa_t *spa, blkptr_cb_t func, void *arg)
 368 {
 369         int err;
 370         uint64_t obj;
 371         dsl_pool_t *dp = spa_get_dsl(spa);
 372         objset_t *mos = dp->dp_meta_objset;
 373
 374         /* visit the MOS */
 375         err = traverse_impl(spa, 0, spa_get_rootblkptr(spa),
 376             0, TRAVERSE_PRE, func, arg);
 377         if (err)
 378                 return (err);
 379
 380         /* visit each dataset */
 381         for (obj = 1; err == 0; err = dmu_object_next(mos, &obj, FALSE, 0)) {
 382                 dmu_object_info_t doi;
 383
 384                 err = dmu_object_info(mos, obj, &doi);
 385                 if (err)
 386                         return (err);
 387
 388                 if (doi.doi_type == DMU_OT_DSL_DATASET) {
 389                         dsl_dataset_t *ds;
 390                         rw_enter(&dp->dp_config_rwlock, RW_READER);
 391                         err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
 392                         rw_exit(&dp->dp_config_rwlock);
 393                         if (err)
 394                                 return (err);
 395                         err = traverse_dataset(ds,
 396                             ds->ds_phys->ds_prev_snap_txg, TRAVERSE_PRE,
 397                             func, arg);
 398                         dsl_dataset_rele(ds, FTAG);
 399                         if (err)
 400                                 return (err);
 401                 }
 402         }
 403         if (err == ESRCH)
 404                 err = 0;
 405         return (err);
 406 }