1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * HAMMER undo - undo buffer/FIFO management. 37 */ 38 39 #include "hammer.h" 40 41 static int 42 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2) 43 { 44 if (node1->offset < node2->offset) 45 return(-1); 46 if (node1->offset > node2->offset) 47 return(1); 48 return(0); 49 } 50 51 RB_GENERATE2(hammer_und_rb_tree, hammer_undo, rb_node, 52 hammer_und_rb_compare, hammer_off_t, offset); 53 54 /* 55 * Convert a zone-3 undo offset into a zone-2 buffer offset. 56 */ 57 hammer_off_t 58 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp) 59 { 60 hammer_volume_t root_volume; 61 hammer_blockmap_t undomap __debugvar; 62 hammer_off_t result_offset; 63 int i; 64 65 KKASSERT(hammer_is_zone_undo(zone3_off)); 66 root_volume = hammer_get_root_volume(hmp, errorp); 67 if (*errorp) 68 return(0); 69 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 70 KKASSERT(HAMMER_ZONE_DECODE(undomap->alloc_offset) == HAMMER_ZONE_UNDO_INDEX); 71 KKASSERT(zone3_off < undomap->alloc_offset); 72 73 /* 74 * undo offsets[i] in zone-2 + 75 * big-block offset of zone-3 address 76 * which results zone-2 address 77 */ 78 i = HAMMER_OFF_SHORT_ENCODE(zone3_off) / HAMMER_BIGBLOCK_SIZE; 79 result_offset = root_volume->ondisk->vol0_undo_array[i] + 80 (zone3_off & HAMMER_BIGBLOCK_MASK64); 81 82 hammer_rel_volume(root_volume, 0); 83 return(result_offset); 84 } 85 86 /* 87 * Generate UNDO record(s) for the block of data at the specified zone1 88 * or zone2 offset. 89 * 90 * The recovery code will execute UNDOs in reverse order, allowing overlaps. 91 * All the UNDOs are executed together so if we already laid one down we 92 * do not have to lay another one down for the same range. 93 * 94 * For HAMMER version 4+ UNDO a 512 byte boundary is enforced and a PAD 95 * will be laid down for any unused space. UNDO FIFO media structures 96 * will implement the hdr_seq field (it used to be reserved01), and 97 * both flush and recovery mechanics will be very different. 98 * 99 * WARNING! See also hammer_generate_redo() in hammer_redo.c 100 */ 101 int 102 hammer_generate_undo(hammer_transaction_t trans, 103 hammer_off_t zone_off, void *base, int len) 104 { 105 hammer_mount_t hmp; 106 hammer_volume_t root_volume; 107 hammer_blockmap_t undomap; 108 hammer_buffer_t buffer = NULL; 109 hammer_fifo_undo_t undo; 110 hammer_fifo_tail_t tail; 111 hammer_off_t next_offset; 112 int error; 113 int bytes; 114 int n; 115 116 hmp = trans->hmp; 117 118 /* 119 * A SYNC record may be required before we can lay down a general 120 * UNDO. This ensures that the nominal recovery span contains 121 * at least one SYNC record telling the recovery code how far 122 * out-of-span it must go to run the REDOs. 123 */ 124 if ((hmp->flags & HAMMER_MOUNT_REDO_SYNC) == 0 && 125 hmp->version >= HAMMER_VOL_VERSION_FOUR) { 126 hammer_generate_redo_sync(trans); 127 } 128 129 /* 130 * Enter the offset into our undo history. If there is an existing 131 * undo we do not have to generate a new one. 132 */ 133 if (hammer_enter_undo_history(hmp, zone_off, len) == EALREADY) 134 return(0); 135 136 root_volume = trans->rootvol; 137 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 138 139 /* no undo recursion */ 140 hammer_modify_volume_noundo(NULL, root_volume); 141 hammer_lock_ex(&hmp->undo_lock); 142 143 /* undo had better not roll over (loose test) */ 144 if (hammer_undo_space(trans) < len + HAMMER_BUFSIZE*3) 145 hpanic("insufficient UNDO/REDO FIFO space for undo!"); 146 147 /* 148 * Loop until the undo for the entire range has been laid down. 149 */ 150 while (len) { 151 /* 152 * Fetch the layout offset in the UNDO FIFO, wrap it as 153 * necessary. 154 */ 155 if (undomap->next_offset == undomap->alloc_offset) 156 undomap->next_offset = HAMMER_ENCODE_UNDO(0); 157 next_offset = undomap->next_offset; 158 159 /* 160 * This is a tail-chasing FIFO, when we hit the start of a new 161 * buffer we don't have to read it in. 162 */ 163 if ((next_offset & HAMMER_BUFMASK) == 0) { 164 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 165 hammer_format_undo(undo, hmp->undo_seqno ^ 0x40000000); 166 } else { 167 undo = hammer_bread(hmp, next_offset, &error, &buffer); 168 } 169 if (error) 170 break; 171 /* no undo recursion */ 172 hammer_modify_buffer_noundo(NULL, buffer); 173 174 /* 175 * Calculate how big a media structure fits up to the next 176 * alignment point and how large a data payload we can 177 * accomodate. 178 * 179 * If n calculates to 0 or negative there is no room for 180 * anything but a PAD. 181 */ 182 bytes = HAMMER_UNDO_ALIGN - 183 ((int)next_offset & HAMMER_UNDO_MASK); 184 n = bytes - 185 (int)sizeof(struct hammer_fifo_undo) - 186 (int)sizeof(struct hammer_fifo_tail); 187 188 /* 189 * If available space is insufficient for any payload 190 * we have to lay down a PAD. 191 * 192 * The minimum PAD is 8 bytes and the head and tail will 193 * overlap each other in that case. PADs do not have 194 * sequence numbers or CRCs. 195 * 196 * A PAD may not start on a boundary. That is, every 197 * 512-byte block in the UNDO/REDO FIFO must begin with 198 * a record containing a sequence number. 199 */ 200 if (n <= 0) { 201 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 202 KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0); 203 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 204 if ((void *)undo != (void *)tail) { 205 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 206 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 207 tail->tail_size = bytes; 208 } 209 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 210 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 211 undo->head.hdr_size = bytes; 212 /* NO CRC OR SEQ NO */ 213 undomap->next_offset += bytes; 214 hammer_modify_buffer_done(buffer); 215 hammer_stats_undo += bytes; 216 continue; 217 } 218 219 /* 220 * Calculate the actual payload and recalculate the size 221 * of the media structure as necessary. 222 */ 223 if (n > len) { 224 n = len; 225 bytes = ((n + HAMMER_HEAD_ALIGN_MASK) & 226 ~HAMMER_HEAD_ALIGN_MASK) + 227 (int)sizeof(struct hammer_fifo_undo) + 228 (int)sizeof(struct hammer_fifo_tail); 229 } 230 if (hammer_debug_general & 0x0080) { 231 hdkprintf("undo %016jx %d %d\n", 232 (intmax_t)next_offset, bytes, n); 233 } 234 235 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 236 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 237 undo->head.hdr_size = bytes; 238 undo->head.hdr_seq = hmp->undo_seqno++; 239 undo->head.hdr_crc = 0; 240 undo->undo_offset = zone_off; 241 undo->undo_data_bytes = n; 242 bcopy(base, undo + 1, n); 243 244 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 245 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 246 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 247 tail->tail_size = bytes; 248 249 KKASSERT(bytes >= sizeof(undo->head)); 250 hammer_crc_set_fifo_head(&undo->head, bytes); 251 undomap->next_offset += bytes; 252 hammer_stats_undo += bytes; 253 254 /* 255 * Before we finish off the buffer we have to deal with any 256 * junk between the end of the media structure we just laid 257 * down and the UNDO alignment boundary. We do this by laying 258 * down a dummy PAD. Even though we will probably overwrite 259 * it almost immediately we have to do this so recovery runs 260 * can iterate the UNDO space without having to depend on 261 * the indices in the volume header. 262 * 263 * This dummy PAD will be overwritten on the next undo so 264 * we do not adjust undomap->next_offset. 265 */ 266 bytes = HAMMER_UNDO_ALIGN - 267 ((int)undomap->next_offset & HAMMER_UNDO_MASK); 268 if (bytes != HAMMER_UNDO_ALIGN) { 269 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 270 undo = (void *)(tail + 1); 271 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 272 if ((void *)undo != (void *)tail) { 273 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 274 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 275 tail->tail_size = bytes; 276 } 277 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 278 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 279 undo->head.hdr_size = bytes; 280 /* NO CRC OR SEQ NO */ 281 } 282 hammer_modify_buffer_done(buffer); 283 284 /* 285 * Adjust for loop 286 */ 287 len -= n; 288 base = (char *)base + n; 289 zone_off += n; 290 } 291 hammer_modify_volume_done(root_volume); 292 hammer_unlock(&hmp->undo_lock); 293 294 if (buffer) 295 hammer_rel_buffer(buffer, 0); 296 return(error); 297 } 298 299 /* 300 * Preformat a new UNDO block. We could read the old one in but we get 301 * better performance if we just pre-format a new one. 302 * 303 * The recovery code always works forwards so the caller just makes sure the 304 * seqno is not contiguous with prior UNDOs or ancient UNDOs now being 305 * overwritten. 306 * 307 * The preformatted UNDO headers use the smallest possible sector size 308 * (512) to ensure that any missed media writes are caught. 309 * 310 * NOTE: Also used by the REDO code. 311 */ 312 void 313 hammer_format_undo(void *base, uint32_t seqno) 314 { 315 hammer_fifo_head_t head; 316 hammer_fifo_tail_t tail; 317 int i; 318 int bytes = HAMMER_UNDO_ALIGN; 319 320 bzero(base, HAMMER_BUFSIZE); 321 322 for (i = 0; i < HAMMER_BUFSIZE; i += bytes) { 323 head = (void *)((char *)base + i); 324 tail = (void *)((char *)head + bytes - sizeof(*tail)); 325 326 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 327 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 328 head->hdr_size = bytes; 329 head->hdr_seq = seqno++; 330 head->hdr_crc = 0; 331 332 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 333 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 334 tail->tail_size = bytes; 335 336 hammer_crc_set_fifo_head(head, bytes); 337 } 338 } 339 340 /* 341 * HAMMER version 4+ conversion support. 342 * 343 * Convert a HAMMER version < 4 UNDO FIFO area to a 4+ UNDO FIFO area. 344 * The 4+ UNDO FIFO area is backwards compatible. The conversion is 345 * needed to initialize the sequence space and place headers on the 346 * new 512-byte undo boundary. 347 */ 348 int 349 hammer_upgrade_undo_4(hammer_transaction_t trans) 350 { 351 hammer_mount_t hmp; 352 hammer_volume_t root_volume; 353 hammer_blockmap_t undomap; 354 hammer_buffer_t buffer = NULL; 355 hammer_fifo_head_t head; 356 hammer_fifo_tail_t tail; 357 hammer_off_t next_offset; 358 uint32_t seqno; 359 int error; 360 int bytes; 361 362 hmp = trans->hmp; 363 364 root_volume = trans->rootvol; 365 366 /* no undo recursion */ 367 hammer_lock_ex(&hmp->undo_lock); 368 hammer_modify_volume_noundo(NULL, root_volume); 369 370 /* 371 * Adjust the in-core undomap and the on-disk undomap. 372 */ 373 next_offset = HAMMER_ENCODE_UNDO(0); 374 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 375 undomap->next_offset = next_offset; 376 undomap->first_offset = next_offset; 377 378 undomap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 379 undomap->next_offset = next_offset; 380 undomap->first_offset = next_offset; 381 382 /* 383 * Loop over the entire UNDO space creating DUMMY entries. Sequence 384 * numbers are assigned. 385 */ 386 seqno = 0; 387 bytes = HAMMER_UNDO_ALIGN; 388 389 while (next_offset != undomap->alloc_offset) { 390 head = hammer_bnew(hmp, next_offset, &error, &buffer); 391 if (error) 392 break; 393 hammer_modify_buffer_noundo(NULL, buffer); 394 tail = (void *)((char *)head + bytes - sizeof(*tail)); 395 396 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 397 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 398 head->hdr_size = bytes; 399 head->hdr_seq = seqno; 400 head->hdr_crc = 0; 401 402 tail = (void *)((char *)head + bytes - sizeof(*tail)); 403 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 404 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 405 tail->tail_size = bytes; 406 407 hammer_crc_set_fifo_head(head, bytes); 408 hammer_modify_buffer_done(buffer); 409 410 hammer_stats_undo += bytes; 411 next_offset += HAMMER_UNDO_ALIGN; 412 ++seqno; 413 } 414 415 /* 416 * The sequence number will be the next sequence number to lay down. 417 */ 418 hmp->undo_seqno = seqno; 419 hmkprintf(hmp, "version upgrade seqno start %08x\n", seqno); 420 421 hammer_modify_volume_done(root_volume); 422 hammer_unlock(&hmp->undo_lock); 423 424 if (buffer) 425 hammer_rel_buffer(buffer, 0); 426 return (error); 427 } 428 429 /* 430 * UNDO HISTORY API 431 * 432 * It is not necessary to layout an undo record for the same address space 433 * multiple times. Maintain a cache of recent undo's. 434 */ 435 436 /* 437 * Enter an undo into the history. Return EALREADY if the request completely 438 * covers a previous request. 439 */ 440 int 441 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes) 442 { 443 hammer_undo_t node; 444 hammer_undo_t onode __debugvar; 445 446 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset); 447 if (node) { 448 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 449 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 450 if (bytes <= node->bytes) 451 return(EALREADY); 452 node->bytes = bytes; 453 return(0); 454 } 455 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) { 456 node = &hmp->undos[hmp->undo_alloc++]; 457 } else { 458 node = TAILQ_FIRST(&hmp->undo_lru_list); 459 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 460 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node); 461 } 462 node->offset = offset; 463 node->bytes = bytes; 464 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 465 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node); 466 KKASSERT(onode == NULL); 467 return(0); 468 } 469 470 void 471 hammer_clear_undo_history(hammer_mount_t hmp) 472 { 473 RB_INIT(&hmp->rb_undo_root); 474 TAILQ_INIT(&hmp->undo_lru_list); 475 hmp->undo_alloc = 0; 476 } 477 478 /* 479 * Return how much of the undo FIFO has been used 480 * 481 * The calculation includes undo FIFO space still reserved from a previous 482 * flush (because it will still be run on recovery if a crash occurs and 483 * we can't overwrite it yet). 484 */ 485 int64_t 486 hammer_undo_used(hammer_transaction_t trans) 487 { 488 hammer_blockmap_t cundomap; 489 hammer_blockmap_t dundomap; 490 int64_t max_bytes __debugvar; 491 int64_t bytes; 492 493 cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 494 dundomap = &trans->rootvol->ondisk-> 495 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 496 497 if (dundomap->first_offset <= cundomap->next_offset) { 498 bytes = cundomap->next_offset - dundomap->first_offset; 499 } else { 500 bytes = cundomap->alloc_offset - dundomap->first_offset + 501 HAMMER_OFF_LONG_ENCODE(cundomap->next_offset); 502 } 503 max_bytes = HAMMER_OFF_SHORT_ENCODE(cundomap->alloc_offset); 504 KKASSERT(bytes <= max_bytes); 505 return(bytes); 506 } 507 508 /* 509 * Return how much of the undo FIFO is available for new records. 510 */ 511 int64_t 512 hammer_undo_space(hammer_transaction_t trans) 513 { 514 hammer_blockmap_t rootmap; 515 int64_t max_bytes; 516 517 rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 518 max_bytes = HAMMER_OFF_SHORT_ENCODE(rootmap->alloc_offset); 519 return(max_bytes - hammer_undo_used(trans)); 520 } 521 522 int64_t 523 hammer_undo_max(hammer_mount_t hmp) 524 { 525 hammer_blockmap_t rootmap; 526 int64_t max_bytes; 527 528 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 529 max_bytes = HAMMER_OFF_SHORT_ENCODE(rootmap->alloc_offset); 530 531 return(max_bytes); 532 } 533 534 /* 535 * Returns 1 if the undo buffer should be reclaimed on release. The 536 * only undo buffer we do NOT want to reclaim is the one at the current 537 * append offset. 538 */ 539 int 540 hammer_undo_reclaim(hammer_io_t io) 541 { 542 hammer_blockmap_t undomap; 543 hammer_off_t next_offset; 544 545 undomap = &io->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 546 next_offset = undomap->next_offset & ~HAMMER_BUFMASK64; 547 if (HAMMER_ITOB(io)->zoneX_offset == next_offset) 548 return(0); 549 return(1); 550 } 551