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 https://opensource.org/licenses/CDDL-1.0. 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 #include <sys/dmu.h> 24 #include <sys/dmu_impl.h> 25 #include <sys/dbuf.h> 26 #include <sys/dnode.h> 27 #include <sys/zfs_context.h> 28 #include <sys/zfs_racct.h> 29 #include <sys/dsl_dataset.h> 30 #include <sys/dmu_objset.h> 31 32 static abd_t * 33 make_abd_for_dbuf(dmu_buf_impl_t *db, abd_t *data, uint64_t offset, 34 uint64_t size) 35 { 36 size_t buf_size = db->db.db_size; 37 abd_t *pre_buf = NULL, *post_buf = NULL, *mbuf = NULL; 38 size_t buf_off = 0; 39 40 ASSERT(MUTEX_HELD(&db->db_mtx)); 41 42 if (offset > db->db.db_offset) { 43 size_t pre_size = offset - db->db.db_offset; 44 pre_buf = abd_alloc_for_io(pre_size, B_TRUE); 45 buf_size -= pre_size; 46 buf_off = 0; 47 } else { 48 buf_off = db->db.db_offset - offset; 49 size -= buf_off; 50 } 51 52 if (size < buf_size) { 53 size_t post_size = buf_size - size; 54 post_buf = abd_alloc_for_io(post_size, B_TRUE); 55 buf_size -= post_size; 56 } 57 58 ASSERT3U(buf_size, >, 0); 59 abd_t *buf = abd_get_offset_size(data, buf_off, buf_size); 60 61 if (pre_buf || post_buf) { 62 mbuf = abd_alloc_gang(); 63 if (pre_buf) 64 abd_gang_add(mbuf, pre_buf, B_TRUE); 65 abd_gang_add(mbuf, buf, B_TRUE); 66 if (post_buf) 67 abd_gang_add(mbuf, post_buf, B_TRUE); 68 } else { 69 mbuf = buf; 70 } 71 72 return (mbuf); 73 } 74 75 static void 76 dmu_read_abd_done(zio_t *zio) 77 { 78 abd_free(zio->io_abd); 79 } 80 81 static void 82 dmu_write_direct_ready(zio_t *zio) 83 { 84 dmu_sync_ready(zio, NULL, zio->io_private); 85 } 86 87 static void 88 dmu_write_direct_done(zio_t *zio) 89 { 90 dmu_sync_arg_t *dsa = zio->io_private; 91 dbuf_dirty_record_t *dr = dsa->dsa_dr; 92 dmu_buf_impl_t *db = dr->dr_dbuf; 93 94 abd_free(zio->io_abd); 95 96 mutex_enter(&db->db_mtx); 97 ASSERT3P(db->db_buf, ==, NULL); 98 ASSERT3P(dr->dt.dl.dr_data, ==, NULL); 99 ASSERT3P(db->db.db_data, ==, NULL); 100 db->db_state = DB_UNCACHED; 101 mutex_exit(&db->db_mtx); 102 103 dmu_sync_done(zio, NULL, zio->io_private); 104 105 if (zio->io_error != 0) { 106 if (zio->io_flags & ZIO_FLAG_DIO_CHKSUM_ERR) 107 ASSERT3U(zio->io_error, ==, EIO); 108 109 /* 110 * In the event of an I/O error this block has been freed in 111 * zio_done() through zio_dva_unallocate(). Calling 112 * dmu_sync_done() above set dr_override_state to 113 * DR_NOT_OVERRIDDEN. In this case when dbuf_undirty() calls 114 * dbuf_unoverride(), it will skip doing zio_free() to free 115 * this block as that was already taken care of. 116 * 117 * Since we are undirtying the record in open-context, we must 118 * have a hold on the db, so it should never be evicted after 119 * calling dbuf_undirty(). 120 */ 121 mutex_enter(&db->db_mtx); 122 VERIFY3B(dbuf_undirty(db, dsa->dsa_tx), ==, B_FALSE); 123 mutex_exit(&db->db_mtx); 124 } 125 126 kmem_free(zio->io_bp, sizeof (blkptr_t)); 127 zio->io_bp = NULL; 128 } 129 130 int 131 dmu_write_direct(zio_t *pio, dmu_buf_impl_t *db, abd_t *data, dmu_tx_t *tx) 132 { 133 objset_t *os = db->db_objset; 134 dsl_dataset_t *ds = dmu_objset_ds(os); 135 zbookmark_phys_t zb; 136 dbuf_dirty_record_t *dr_head; 137 138 SET_BOOKMARK(&zb, ds->ds_object, 139 db->db.db_object, db->db_level, db->db_blkid); 140 141 DB_DNODE_ENTER(db); 142 zio_prop_t zp; 143 dmu_write_policy(os, DB_DNODE(db), db->db_level, 144 WP_DMU_SYNC | WP_DIRECT_WR, &zp); 145 DB_DNODE_EXIT(db); 146 147 /* 148 * Dirty this dbuf with DB_NOFILL since we will not have any data 149 * associated with the dbuf. 150 */ 151 dmu_buf_will_clone_or_dio(&db->db, tx); 152 153 mutex_enter(&db->db_mtx); 154 155 uint64_t txg = dmu_tx_get_txg(tx); 156 ASSERT3U(txg, >, spa_last_synced_txg(os->os_spa)); 157 ASSERT3U(txg, >, spa_syncing_txg(os->os_spa)); 158 159 dr_head = list_head(&db->db_dirty_records); 160 ASSERT3U(dr_head->dr_txg, ==, txg); 161 dr_head->dt.dl.dr_diowrite = B_TRUE; 162 dr_head->dr_accounted = db->db.db_size; 163 164 blkptr_t *bp = kmem_alloc(sizeof (blkptr_t), KM_SLEEP); 165 if (db->db_blkptr != NULL) { 166 /* 167 * Fill in bp with the current block pointer so that 168 * the nopwrite code can check if we're writing the same 169 * data that's already on disk. 170 */ 171 *bp = *db->db_blkptr; 172 } else { 173 memset(bp, 0, sizeof (blkptr_t)); 174 } 175 176 /* 177 * Disable nopwrite if the current block pointer could change 178 * before this TXG syncs. 179 */ 180 if (list_next(&db->db_dirty_records, dr_head) != NULL) 181 zp.zp_nopwrite = B_FALSE; 182 183 ASSERT3S(dr_head->dt.dl.dr_override_state, ==, DR_NOT_OVERRIDDEN); 184 dr_head->dt.dl.dr_override_state = DR_IN_DMU_SYNC; 185 186 mutex_exit(&db->db_mtx); 187 188 dmu_objset_willuse_space(os, dr_head->dr_accounted, tx); 189 190 dmu_sync_arg_t *dsa = kmem_zalloc(sizeof (dmu_sync_arg_t), KM_SLEEP); 191 dsa->dsa_dr = dr_head; 192 dsa->dsa_tx = tx; 193 194 zio_t *zio = zio_write(pio, os->os_spa, txg, bp, data, 195 db->db.db_size, db->db.db_size, &zp, 196 dmu_write_direct_ready, NULL, dmu_write_direct_done, dsa, 197 ZIO_PRIORITY_SYNC_WRITE, ZIO_FLAG_CANFAIL, &zb); 198 199 if (pio == NULL) 200 return (zio_wait(zio)); 201 202 zio_nowait(zio); 203 204 return (0); 205 } 206 207 int 208 dmu_write_abd(dnode_t *dn, uint64_t offset, uint64_t size, 209 abd_t *data, uint32_t flags, dmu_tx_t *tx) 210 { 211 dmu_buf_t **dbp; 212 spa_t *spa = dn->dn_objset->os_spa; 213 int numbufs, err; 214 215 ASSERT(flags & DMU_DIRECTIO); 216 217 err = dmu_buf_hold_array_by_dnode(dn, offset, 218 size, B_FALSE, FTAG, &numbufs, &dbp, flags); 219 if (err) 220 return (err); 221 222 zio_t *pio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 223 224 for (int i = 0; i < numbufs && err == 0; i++) { 225 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbp[i]; 226 227 abd_t *abd = abd_get_offset_size(data, 228 db->db.db_offset - offset, dn->dn_datablksz); 229 230 zfs_racct_write(spa, db->db.db_size, 1, flags); 231 err = dmu_write_direct(pio, db, abd, tx); 232 ASSERT0(err); 233 } 234 235 err = zio_wait(pio); 236 237 /* 238 * The dbuf must be held until the Direct I/O write has completed in 239 * the event there was any errors and dbuf_undirty() was called. 240 */ 241 dmu_buf_rele_array(dbp, numbufs, FTAG); 242 243 return (err); 244 } 245 246 int 247 dmu_read_abd(dnode_t *dn, uint64_t offset, uint64_t size, 248 abd_t *data, uint32_t flags) 249 { 250 objset_t *os = dn->dn_objset; 251 spa_t *spa = os->os_spa; 252 dmu_buf_t **dbp; 253 int numbufs, err; 254 255 ASSERT(flags & DMU_DIRECTIO); 256 257 err = dmu_buf_hold_array_by_dnode(dn, offset, 258 size, B_FALSE, FTAG, &numbufs, &dbp, flags); 259 if (err) 260 return (err); 261 262 zio_t *rio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 263 264 for (int i = 0; i < numbufs; i++) { 265 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbp[i]; 266 abd_t *mbuf; 267 zbookmark_phys_t zb; 268 blkptr_t *bp; 269 270 mutex_enter(&db->db_mtx); 271 272 SET_BOOKMARK(&zb, dmu_objset_ds(os)->ds_object, 273 db->db.db_object, db->db_level, db->db_blkid); 274 275 /* 276 * If there is another read for this dbuf, we will wait for 277 * that to complete first before checking the db_state below. 278 */ 279 while (db->db_state == DB_READ) 280 cv_wait(&db->db_changed, &db->db_mtx); 281 282 err = dmu_buf_get_bp_from_dbuf(db, &bp); 283 if (err) { 284 mutex_exit(&db->db_mtx); 285 goto error; 286 } 287 288 /* 289 * There is no need to read if this is a hole or the data is 290 * cached. This will not be considered a direct read for IO 291 * accounting in the same way that an ARC hit is not counted. 292 */ 293 if (bp == NULL || BP_IS_HOLE(bp) || db->db_state == DB_CACHED) { 294 size_t aoff = offset < db->db.db_offset ? 295 db->db.db_offset - offset : 0; 296 size_t boff = offset > db->db.db_offset ? 297 offset - db->db.db_offset : 0; 298 size_t len = MIN(size - aoff, db->db.db_size - boff); 299 300 if (db->db_state == DB_CACHED) { 301 /* 302 * We need to untransformed the ARC buf data 303 * before we copy it over. 304 */ 305 err = dmu_buf_untransform_direct(db, spa); 306 ASSERT0(err); 307 abd_copy_from_buf_off(data, 308 (char *)db->db.db_data + boff, aoff, len); 309 } else { 310 abd_zero_off(data, aoff, len); 311 } 312 313 mutex_exit(&db->db_mtx); 314 continue; 315 } 316 317 mbuf = make_abd_for_dbuf(db, data, offset, size); 318 ASSERT3P(mbuf, !=, NULL); 319 320 /* 321 * The dbuf mutex (db_mtx) must be held when creating the ZIO 322 * for the read. The BP returned from 323 * dmu_buf_get_bp_from_dbuf() could be from a pending block 324 * clone or a yet to be synced Direct I/O write that is in the 325 * dbuf's dirty record. When zio_read() is called, zio_create() 326 * will make a copy of the BP. However, if zio_read() is called 327 * without the mutex being held then the dirty record from the 328 * dbuf could be freed in dbuf_write_done() resulting in garbage 329 * being set for the zio BP. 330 */ 331 zio_t *cio = zio_read(rio, spa, bp, mbuf, db->db.db_size, 332 dmu_read_abd_done, NULL, ZIO_PRIORITY_SYNC_READ, 333 ZIO_FLAG_CANFAIL, &zb); 334 mutex_exit(&db->db_mtx); 335 336 zfs_racct_read(spa, db->db.db_size, 1, flags); 337 zio_nowait(cio); 338 } 339 340 dmu_buf_rele_array(dbp, numbufs, FTAG); 341 342 return (zio_wait(rio)); 343 344 error: 345 dmu_buf_rele_array(dbp, numbufs, FTAG); 346 (void) zio_wait(rio); 347 return (err); 348 } 349 350 #ifdef _KERNEL 351 int 352 dmu_read_uio_direct(dnode_t *dn, zfs_uio_t *uio, uint64_t size) 353 { 354 offset_t offset = zfs_uio_offset(uio); 355 offset_t page_index = (offset - zfs_uio_soffset(uio)) >> PAGESHIFT; 356 int err; 357 358 ASSERT(uio->uio_extflg & UIO_DIRECT); 359 ASSERT3U(page_index, <, uio->uio_dio.npages); 360 361 abd_t *data = abd_alloc_from_pages(&uio->uio_dio.pages[page_index], 362 offset & (PAGESIZE - 1), size); 363 err = dmu_read_abd(dn, offset, size, data, DMU_DIRECTIO); 364 abd_free(data); 365 366 if (err == 0) 367 zfs_uioskip(uio, size); 368 369 return (err); 370 } 371 372 int 373 dmu_write_uio_direct(dnode_t *dn, zfs_uio_t *uio, uint64_t size, dmu_tx_t *tx) 374 { 375 offset_t offset = zfs_uio_offset(uio); 376 offset_t page_index = (offset - zfs_uio_soffset(uio)) >> PAGESHIFT; 377 int err; 378 379 ASSERT(uio->uio_extflg & UIO_DIRECT); 380 ASSERT3U(page_index, <, uio->uio_dio.npages); 381 382 abd_t *data = abd_alloc_from_pages(&uio->uio_dio.pages[page_index], 383 offset & (PAGESIZE - 1), size); 384 err = dmu_write_abd(dn, offset, size, data, DMU_DIRECTIO, tx); 385 abd_free(data); 386 387 if (err == 0) 388 zfs_uioskip(uio, size); 389 390 return (err); 391 } 392 #endif /* _KERNEL */ 393 394 EXPORT_SYMBOL(dmu_read_uio_direct); 395 EXPORT_SYMBOL(dmu_write_uio_direct); 396