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 = (zone3_off & HAMMER_OFF_SHORT_MASK) / 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 FIFO space!"); 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 = 157 HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0); 158 } 159 next_offset = undomap->next_offset; 160 161 /* 162 * This is a tail-chasing FIFO, when we hit the start of a new 163 * buffer we don't have to read it in. 164 */ 165 if ((next_offset & HAMMER_BUFMASK) == 0) { 166 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 167 hammer_format_undo(undo, hmp->undo_seqno ^ 0x40000000); 168 } else { 169 undo = hammer_bread(hmp, next_offset, &error, &buffer); 170 } 171 if (error) 172 break; 173 /* no undo recursion */ 174 hammer_modify_buffer_noundo(NULL, buffer); 175 176 /* 177 * Calculate how big a media structure fits up to the next 178 * alignment point and how large a data payload we can 179 * accomodate. 180 * 181 * If n calculates to 0 or negative there is no room for 182 * anything but a PAD. 183 */ 184 bytes = HAMMER_UNDO_ALIGN - 185 ((int)next_offset & HAMMER_UNDO_MASK); 186 n = bytes - 187 (int)sizeof(struct hammer_fifo_undo) - 188 (int)sizeof(struct hammer_fifo_tail); 189 190 /* 191 * If available space is insufficient for any payload 192 * we have to lay down a PAD. 193 * 194 * The minimum PAD is 8 bytes and the head and tail will 195 * overlap each other in that case. PADs do not have 196 * sequence numbers or CRCs. 197 * 198 * A PAD may not start on a boundary. That is, every 199 * 512-byte block in the UNDO/REDO FIFO must begin with 200 * a record containing a sequence number. 201 */ 202 if (n <= 0) { 203 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 204 KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0); 205 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 206 if ((void *)undo != (void *)tail) { 207 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 208 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 209 tail->tail_size = bytes; 210 } 211 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 212 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 213 undo->head.hdr_size = bytes; 214 /* NO CRC OR SEQ NO */ 215 undomap->next_offset += bytes; 216 hammer_modify_buffer_done(buffer); 217 hammer_stats_undo += bytes; 218 continue; 219 } 220 221 /* 222 * Calculate the actual payload and recalculate the size 223 * of the media structure as necessary. 224 */ 225 if (n > len) { 226 n = len; 227 bytes = ((n + HAMMER_HEAD_ALIGN_MASK) & 228 ~HAMMER_HEAD_ALIGN_MASK) + 229 (int)sizeof(struct hammer_fifo_undo) + 230 (int)sizeof(struct hammer_fifo_tail); 231 } 232 if (hammer_debug_general & 0x0080) { 233 hdkprintf("undo %016jx %d %d\n", 234 (intmax_t)next_offset, bytes, n); 235 } 236 237 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 238 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 239 undo->head.hdr_size = bytes; 240 undo->head.hdr_seq = hmp->undo_seqno++; 241 undo->head.hdr_crc = 0; 242 undo->undo_offset = zone_off; 243 undo->undo_data_bytes = n; 244 bcopy(base, undo + 1, n); 245 246 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 247 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 248 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 249 tail->tail_size = bytes; 250 251 KKASSERT(bytes >= sizeof(undo->head)); 252 hammer_crc_set_fifo_head(&undo->head, bytes); 253 undomap->next_offset += bytes; 254 hammer_stats_undo += bytes; 255 256 /* 257 * Before we finish off the buffer we have to deal with any 258 * junk between the end of the media structure we just laid 259 * down and the UNDO alignment boundary. We do this by laying 260 * down a dummy PAD. Even though we will probably overwrite 261 * it almost immediately we have to do this so recovery runs 262 * can iterate the UNDO space without having to depend on 263 * the indices in the volume header. 264 * 265 * This dummy PAD will be overwritten on the next undo so 266 * we do not adjust undomap->next_offset. 267 */ 268 bytes = HAMMER_UNDO_ALIGN - 269 ((int)undomap->next_offset & HAMMER_UNDO_MASK); 270 if (bytes != HAMMER_UNDO_ALIGN) { 271 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 272 undo = (void *)(tail + 1); 273 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 274 if ((void *)undo != (void *)tail) { 275 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 276 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 277 tail->tail_size = bytes; 278 } 279 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 280 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 281 undo->head.hdr_size = bytes; 282 /* NO CRC OR SEQ NO */ 283 } 284 hammer_modify_buffer_done(buffer); 285 286 /* 287 * Adjust for loop 288 */ 289 len -= n; 290 base = (char *)base + n; 291 zone_off += n; 292 } 293 hammer_modify_volume_done(root_volume); 294 hammer_unlock(&hmp->undo_lock); 295 296 if (buffer) 297 hammer_rel_buffer(buffer, 0); 298 return(error); 299 } 300 301 /* 302 * Preformat a new UNDO block. We could read the old one in but we get 303 * better performance if we just pre-format a new one. 304 * 305 * The recovery code always works forwards so the caller just makes sure the 306 * seqno is not contiguous with prior UNDOs or ancient UNDOs now being 307 * overwritten. 308 * 309 * The preformatted UNDO headers use the smallest possible sector size 310 * (512) to ensure that any missed media writes are caught. 311 * 312 * NOTE: Also used by the REDO code. 313 */ 314 void 315 hammer_format_undo(void *base, uint32_t seqno) 316 { 317 hammer_fifo_head_t head; 318 hammer_fifo_tail_t tail; 319 int i; 320 int bytes = HAMMER_UNDO_ALIGN; 321 322 bzero(base, HAMMER_BUFSIZE); 323 324 for (i = 0; i < HAMMER_BUFSIZE; i += bytes) { 325 head = (void *)((char *)base + i); 326 tail = (void *)((char *)head + bytes - sizeof(*tail)); 327 328 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 329 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 330 head->hdr_size = bytes; 331 head->hdr_seq = seqno++; 332 head->hdr_crc = 0; 333 334 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 335 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 336 tail->tail_size = bytes; 337 338 hammer_crc_set_fifo_head(head, bytes); 339 } 340 } 341 342 /* 343 * HAMMER version 4+ conversion support. 344 * 345 * Convert a HAMMER version < 4 UNDO FIFO area to a 4+ UNDO FIFO area. 346 * The 4+ UNDO FIFO area is backwards compatible. The conversion is 347 * needed to initialize the sequence space and place headers on the 348 * new 512-byte undo boundary. 349 */ 350 int 351 hammer_upgrade_undo_4(hammer_transaction_t trans) 352 { 353 hammer_mount_t hmp; 354 hammer_volume_t root_volume; 355 hammer_blockmap_t undomap; 356 hammer_buffer_t buffer = NULL; 357 hammer_fifo_head_t head; 358 hammer_fifo_tail_t tail; 359 hammer_off_t next_offset; 360 uint32_t seqno; 361 int error; 362 int bytes; 363 364 hmp = trans->hmp; 365 366 root_volume = trans->rootvol; 367 368 /* no undo recursion */ 369 hammer_lock_ex(&hmp->undo_lock); 370 hammer_modify_volume_noundo(NULL, root_volume); 371 372 /* 373 * Adjust the in-core undomap and the on-disk undomap. 374 */ 375 next_offset = HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0); 376 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 377 undomap->next_offset = next_offset; 378 undomap->first_offset = next_offset; 379 380 undomap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 381 undomap->next_offset = next_offset; 382 undomap->first_offset = next_offset; 383 384 /* 385 * Loop over the entire UNDO space creating DUMMY entries. Sequence 386 * numbers are assigned. 387 */ 388 seqno = 0; 389 bytes = HAMMER_UNDO_ALIGN; 390 391 while (next_offset != undomap->alloc_offset) { 392 head = hammer_bnew(hmp, next_offset, &error, &buffer); 393 if (error) 394 break; 395 hammer_modify_buffer_noundo(NULL, buffer); 396 tail = (void *)((char *)head + bytes - sizeof(*tail)); 397 398 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 399 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 400 head->hdr_size = bytes; 401 head->hdr_seq = seqno; 402 head->hdr_crc = 0; 403 404 tail = (void *)((char *)head + bytes - sizeof(*tail)); 405 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 406 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 407 tail->tail_size = bytes; 408 409 hammer_crc_set_fifo_head(head, bytes); 410 hammer_modify_buffer_done(buffer); 411 412 hammer_stats_undo += bytes; 413 next_offset += HAMMER_UNDO_ALIGN; 414 ++seqno; 415 } 416 417 /* 418 * The sequence number will be the next sequence number to lay down. 419 */ 420 hmp->undo_seqno = seqno; 421 hmkprintf(hmp, "version upgrade seqno start %08x\n", seqno); 422 423 hammer_modify_volume_done(root_volume); 424 hammer_unlock(&hmp->undo_lock); 425 426 if (buffer) 427 hammer_rel_buffer(buffer, 0); 428 return (error); 429 } 430 431 /* 432 * UNDO HISTORY API 433 * 434 * It is not necessary to layout an undo record for the same address space 435 * multiple times. Maintain a cache of recent undo's. 436 */ 437 438 /* 439 * Enter an undo into the history. Return EALREADY if the request completely 440 * covers a previous request. 441 */ 442 int 443 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes) 444 { 445 hammer_undo_t node; 446 hammer_undo_t onode __debugvar; 447 448 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset); 449 if (node) { 450 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 451 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 452 if (bytes <= node->bytes) 453 return(EALREADY); 454 node->bytes = bytes; 455 return(0); 456 } 457 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) { 458 node = &hmp->undos[hmp->undo_alloc++]; 459 } else { 460 node = TAILQ_FIRST(&hmp->undo_lru_list); 461 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 462 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node); 463 } 464 node->offset = offset; 465 node->bytes = bytes; 466 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 467 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node); 468 KKASSERT(onode == NULL); 469 return(0); 470 } 471 472 void 473 hammer_clear_undo_history(hammer_mount_t hmp) 474 { 475 RB_INIT(&hmp->rb_undo_root); 476 TAILQ_INIT(&hmp->undo_lru_list); 477 hmp->undo_alloc = 0; 478 } 479 480 /* 481 * Return how much of the undo FIFO has been used 482 * 483 * The calculation includes undo FIFO space still reserved from a previous 484 * flush (because it will still be run on recovery if a crash occurs and 485 * we can't overwrite it yet). 486 */ 487 int64_t 488 hammer_undo_used(hammer_transaction_t trans) 489 { 490 hammer_blockmap_t cundomap; 491 hammer_blockmap_t dundomap; 492 int64_t max_bytes __debugvar; 493 int64_t bytes; 494 495 cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 496 dundomap = &trans->rootvol->ondisk-> 497 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 498 499 if (dundomap->first_offset <= cundomap->next_offset) { 500 bytes = cundomap->next_offset - dundomap->first_offset; 501 } else { 502 bytes = cundomap->alloc_offset - dundomap->first_offset + 503 (cundomap->next_offset & HAMMER_OFF_LONG_MASK); 504 } 505 max_bytes = cundomap->alloc_offset & HAMMER_OFF_SHORT_MASK; 506 KKASSERT(bytes <= max_bytes); 507 return(bytes); 508 } 509 510 /* 511 * Return how much of the undo FIFO is available for new records. 512 */ 513 int64_t 514 hammer_undo_space(hammer_transaction_t trans) 515 { 516 hammer_blockmap_t rootmap; 517 int64_t max_bytes; 518 519 rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 520 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 521 return(max_bytes - hammer_undo_used(trans)); 522 } 523 524 int64_t 525 hammer_undo_max(hammer_mount_t hmp) 526 { 527 hammer_blockmap_t rootmap; 528 int64_t max_bytes; 529 530 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 531 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 532 533 return(max_bytes); 534 } 535 536 /* 537 * Returns 1 if the undo buffer should be reclaimed on release. The 538 * only undo buffer we do NOT want to reclaim is the one at the current 539 * append offset. 540 */ 541 int 542 hammer_undo_reclaim(hammer_io_t io) 543 { 544 hammer_blockmap_t undomap; 545 hammer_off_t next_offset; 546 547 undomap = &io->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 548 next_offset = undomap->next_offset & ~HAMMER_BUFMASK64; 549 if (HAMMER_ITOB(io)->zoneX_offset == next_offset) 550 return(0); 551 return(1); 552 } 553