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 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2); 42 43 RB_GENERATE2(hammer_und_rb_tree, hammer_undo, rb_node, 44 hammer_und_rb_compare, hammer_off_t, offset); 45 46 /* 47 * Convert a zone-3 undo offset into a zone-2 buffer offset. 48 */ 49 hammer_off_t 50 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp) 51 { 52 hammer_volume_t root_volume; 53 hammer_blockmap_t undomap __debugvar; 54 hammer_off_t result_offset; 55 int i; 56 57 KKASSERT((zone3_off & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_UNDO); 58 root_volume = hammer_get_root_volume(hmp, errorp); 59 if (*errorp) 60 return(0); 61 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 62 KKASSERT(HAMMER_ZONE_DECODE(undomap->alloc_offset) == HAMMER_ZONE_UNDO_INDEX); 63 KKASSERT(zone3_off < undomap->alloc_offset); 64 65 i = (zone3_off & HAMMER_OFF_SHORT_MASK) / HAMMER_LARGEBLOCK_SIZE; 66 result_offset = root_volume->ondisk->vol0_undo_array[i] + 67 (zone3_off & HAMMER_LARGEBLOCK_MASK64); 68 69 hammer_rel_volume(root_volume, 0); 70 return(result_offset); 71 } 72 73 /* 74 * Generate UNDO record(s) for the block of data at the specified zone1 75 * or zone2 offset. 76 * 77 * The recovery code will execute UNDOs in reverse order, allowing overlaps. 78 * All the UNDOs are executed together so if we already laid one down we 79 * do not have to lay another one down for the same range. 80 * 81 * For HAMMER version 4+ UNDO a 512 byte boundary is enforced and a PAD 82 * will be laid down for any unused space. UNDO FIFO media structures 83 * will implement the hdr_seq field (it used to be reserved01), and 84 * both flush and recovery mechanics will be very different. 85 * 86 * WARNING! See also hammer_generate_redo() in hammer_redo.c 87 */ 88 int 89 hammer_generate_undo(hammer_transaction_t trans, 90 hammer_off_t zone_off, void *base, int len) 91 { 92 hammer_mount_t hmp; 93 hammer_volume_t root_volume; 94 hammer_blockmap_t undomap; 95 hammer_buffer_t buffer = NULL; 96 hammer_fifo_undo_t undo; 97 hammer_fifo_tail_t tail; 98 hammer_off_t next_offset; 99 int error; 100 int bytes; 101 int n; 102 103 hmp = trans->hmp; 104 105 /* 106 * A SYNC record may be required before we can lay down a general 107 * UNDO. This ensures that the nominal recovery span contains 108 * at least one SYNC record telling the recovery code how far 109 * out-of-span it must go to run the REDOs. 110 */ 111 if ((hmp->flags & HAMMER_MOUNT_REDO_SYNC) == 0 && 112 hmp->version >= HAMMER_VOL_VERSION_FOUR) { 113 hammer_generate_redo_sync(trans); 114 } 115 116 /* 117 * Enter the offset into our undo history. If there is an existing 118 * undo we do not have to generate a new one. 119 */ 120 if (hammer_enter_undo_history(hmp, zone_off, len) == EALREADY) 121 return(0); 122 123 root_volume = trans->rootvol; 124 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 125 126 /* no undo recursion */ 127 hammer_modify_volume(NULL, root_volume, NULL, 0); 128 hammer_lock_ex(&hmp->undo_lock); 129 130 /* undo had better not roll over (loose test) */ 131 if (hammer_undo_space(trans) < len + HAMMER_BUFSIZE*3) 132 panic("hammer: insufficient undo FIFO space!"); 133 134 /* 135 * Loop until the undo for the entire range has been laid down. 136 */ 137 while (len) { 138 /* 139 * Fetch the layout offset in the UNDO FIFO, wrap it as 140 * necessary. 141 */ 142 if (undomap->next_offset == undomap->alloc_offset) { 143 undomap->next_offset = 144 HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0); 145 } 146 next_offset = undomap->next_offset; 147 148 /* 149 * This is a tail-chasing FIFO, when we hit the start of a new 150 * buffer we don't have to read it in. 151 */ 152 if ((next_offset & HAMMER_BUFMASK) == 0) { 153 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 154 hammer_format_undo(undo, hmp->undo_seqno ^ 0x40000000); 155 } else { 156 undo = hammer_bread(hmp, next_offset, &error, &buffer); 157 } 158 if (error) 159 break; 160 hammer_modify_buffer(NULL, buffer, NULL, 0); 161 162 /* 163 * Calculate how big a media structure fits up to the next 164 * alignment point and how large a data payload we can 165 * accomodate. 166 * 167 * If n calculates to 0 or negative there is no room for 168 * anything but a PAD. 169 */ 170 bytes = HAMMER_UNDO_ALIGN - 171 ((int)next_offset & HAMMER_UNDO_MASK); 172 n = bytes - 173 (int)sizeof(struct hammer_fifo_undo) - 174 (int)sizeof(struct hammer_fifo_tail); 175 176 /* 177 * If available space is insufficient for any payload 178 * we have to lay down a PAD. 179 * 180 * The minimum PAD is 8 bytes and the head and tail will 181 * overlap each other in that case. PADs do not have 182 * sequence numbers or CRCs. 183 * 184 * A PAD may not start on a boundary. That is, every 185 * 512-byte block in the UNDO/REDO FIFO must begin with 186 * a record containing a sequence number. 187 */ 188 if (n <= 0) { 189 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 190 KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0); 191 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 192 if ((void *)undo != (void *)tail) { 193 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 194 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 195 tail->tail_size = bytes; 196 } 197 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 198 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 199 undo->head.hdr_size = bytes; 200 /* NO CRC OR SEQ NO */ 201 undomap->next_offset += bytes; 202 hammer_modify_buffer_done(buffer); 203 hammer_stats_undo += bytes; 204 continue; 205 } 206 207 /* 208 * Calculate the actual payload and recalculate the size 209 * of the media structure as necessary. 210 */ 211 if (n > len) { 212 n = len; 213 bytes = ((n + HAMMER_HEAD_ALIGN_MASK) & 214 ~HAMMER_HEAD_ALIGN_MASK) + 215 (int)sizeof(struct hammer_fifo_undo) + 216 (int)sizeof(struct hammer_fifo_tail); 217 } 218 if (hammer_debug_general & 0x0080) { 219 kprintf("undo %016llx %d %d\n", 220 (long long)next_offset, bytes, n); 221 } 222 223 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 224 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 225 undo->head.hdr_size = bytes; 226 undo->head.hdr_seq = hmp->undo_seqno++; 227 undo->head.hdr_crc = 0; 228 undo->undo_offset = zone_off; 229 undo->undo_data_bytes = n; 230 bcopy(base, undo + 1, n); 231 232 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 233 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 234 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 235 tail->tail_size = bytes; 236 237 KKASSERT(bytes >= sizeof(undo->head)); 238 undo->head.hdr_crc = crc32(undo, HAMMER_FIFO_HEAD_CRCOFF) ^ 239 crc32(&undo->head + 1, bytes - sizeof(undo->head)); 240 undomap->next_offset += bytes; 241 hammer_stats_undo += bytes; 242 243 /* 244 * Before we finish off the buffer we have to deal with any 245 * junk between the end of the media structure we just laid 246 * down and the UNDO alignment boundary. We do this by laying 247 * down a dummy PAD. Even though we will probably overwrite 248 * it almost immediately we have to do this so recovery runs 249 * can iterate the UNDO space without having to depend on 250 * the indices in the volume header. 251 * 252 * This dummy PAD will be overwritten on the next undo so 253 * we do not adjust undomap->next_offset. 254 */ 255 bytes = HAMMER_UNDO_ALIGN - 256 ((int)undomap->next_offset & HAMMER_UNDO_MASK); 257 if (bytes != HAMMER_UNDO_ALIGN) { 258 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 259 undo = (void *)(tail + 1); 260 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 261 if ((void *)undo != (void *)tail) { 262 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 263 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 264 tail->tail_size = bytes; 265 } 266 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 267 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 268 undo->head.hdr_size = bytes; 269 /* NO CRC OR SEQ NO */ 270 } 271 hammer_modify_buffer_done(buffer); 272 273 /* 274 * Adjust for loop 275 */ 276 len -= n; 277 base = (char *)base + n; 278 zone_off += n; 279 } 280 hammer_modify_volume_done(root_volume); 281 hammer_unlock(&hmp->undo_lock); 282 283 if (buffer) 284 hammer_rel_buffer(buffer, 0); 285 return(error); 286 } 287 288 /* 289 * Preformat a new UNDO block. We could read the old one in but we get 290 * better performance if we just pre-format a new one. 291 * 292 * The recovery code always works forwards so the caller just makes sure the 293 * seqno is not contiguous with prior UNDOs or ancient UNDOs now being 294 * overwritten. 295 * 296 * The preformatted UNDO headers use the smallest possible sector size 297 * (512) to ensure that any missed media writes are caught. 298 * 299 * NOTE: Also used by the REDO code. 300 */ 301 void 302 hammer_format_undo(void *base, u_int32_t seqno) 303 { 304 hammer_fifo_head_t head; 305 hammer_fifo_tail_t tail; 306 int i; 307 int bytes = HAMMER_UNDO_ALIGN; 308 309 bzero(base, HAMMER_BUFSIZE); 310 311 for (i = 0; i < HAMMER_BUFSIZE; i += bytes) { 312 head = (void *)((char *)base + i); 313 tail = (void *)((char *)head + bytes - sizeof(*tail)); 314 315 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 316 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 317 head->hdr_size = bytes; 318 head->hdr_seq = seqno++; 319 head->hdr_crc = 0; 320 321 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 322 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 323 tail->tail_size = bytes; 324 325 head->hdr_crc = crc32(head, HAMMER_FIFO_HEAD_CRCOFF) ^ 326 crc32(head + 1, bytes - sizeof(*head)); 327 } 328 } 329 330 /* 331 * HAMMER version 4+ conversion support. 332 * 333 * Convert a HAMMER version < 4 UNDO FIFO area to a 4+ UNDO FIFO area. 334 * The 4+ UNDO FIFO area is backwards compatible. The conversion is 335 * needed to initialize the sequence space and place headers on the 336 * new 512-byte undo boundary. 337 */ 338 int 339 hammer_upgrade_undo_4(hammer_transaction_t trans) 340 { 341 hammer_mount_t hmp; 342 hammer_volume_t root_volume; 343 hammer_blockmap_t undomap; 344 hammer_buffer_t buffer = NULL; 345 hammer_fifo_head_t head; 346 hammer_fifo_tail_t tail; 347 hammer_off_t next_offset; 348 u_int32_t seqno; 349 int error; 350 int bytes; 351 352 hmp = trans->hmp; 353 354 root_volume = trans->rootvol; 355 356 /* no undo recursion */ 357 hammer_lock_ex(&hmp->undo_lock); 358 hammer_modify_volume(NULL, root_volume, NULL, 0); 359 360 /* 361 * Adjust the in-core undomap and the on-disk undomap. 362 */ 363 next_offset = HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0); 364 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 365 undomap->next_offset = next_offset; 366 undomap->first_offset = next_offset; 367 368 undomap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 369 undomap->next_offset = next_offset; 370 undomap->first_offset = next_offset; 371 372 /* 373 * Loop over the entire UNDO space creating DUMMY entries. Sequence 374 * numbers are assigned. 375 */ 376 seqno = 0; 377 bytes = HAMMER_UNDO_ALIGN; 378 379 while (next_offset != undomap->alloc_offset) { 380 head = hammer_bnew(hmp, next_offset, &error, &buffer); 381 if (error) 382 break; 383 hammer_modify_buffer(NULL, buffer, NULL, 0); 384 tail = (void *)((char *)head + bytes - sizeof(*tail)); 385 386 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 387 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 388 head->hdr_size = bytes; 389 head->hdr_seq = seqno; 390 head->hdr_crc = 0; 391 392 tail = (void *)((char *)head + bytes - sizeof(*tail)); 393 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 394 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 395 tail->tail_size = bytes; 396 397 head->hdr_crc = crc32(head, HAMMER_FIFO_HEAD_CRCOFF) ^ 398 crc32(head + 1, bytes - sizeof(*head)); 399 hammer_modify_buffer_done(buffer); 400 401 hammer_stats_undo += bytes; 402 next_offset += HAMMER_UNDO_ALIGN; 403 ++seqno; 404 } 405 406 /* 407 * The sequence number will be the next sequence number to lay down. 408 */ 409 hmp->undo_seqno = seqno; 410 kprintf("version upgrade seqno start %08x\n", seqno); 411 412 hammer_modify_volume_done(root_volume); 413 hammer_unlock(&hmp->undo_lock); 414 415 if (buffer) 416 hammer_rel_buffer(buffer, 0); 417 return (error); 418 } 419 420 /* 421 * UNDO HISTORY API 422 * 423 * It is not necessary to layout an undo record for the same address space 424 * multiple times. Maintain a cache of recent undo's. 425 */ 426 427 /* 428 * Enter an undo into the history. Return EALREADY if the request completely 429 * covers a previous request. 430 */ 431 int 432 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes) 433 { 434 hammer_undo_t node; 435 hammer_undo_t onode __debugvar; 436 437 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset); 438 if (node) { 439 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 440 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 441 if (bytes <= node->bytes) 442 return(EALREADY); 443 node->bytes = bytes; 444 return(0); 445 } 446 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) { 447 node = &hmp->undos[hmp->undo_alloc++]; 448 } else { 449 node = TAILQ_FIRST(&hmp->undo_lru_list); 450 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 451 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node); 452 } 453 node->offset = offset; 454 node->bytes = bytes; 455 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 456 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node); 457 KKASSERT(onode == NULL); 458 return(0); 459 } 460 461 void 462 hammer_clear_undo_history(hammer_mount_t hmp) 463 { 464 RB_INIT(&hmp->rb_undo_root); 465 TAILQ_INIT(&hmp->undo_lru_list); 466 hmp->undo_alloc = 0; 467 } 468 469 /* 470 * Return how much of the undo FIFO has been used 471 * 472 * The calculation includes undo FIFO space still reserved from a previous 473 * flush (because it will still be run on recovery if a crash occurs and 474 * we can't overwrite it yet). 475 */ 476 int64_t 477 hammer_undo_used(hammer_transaction_t trans) 478 { 479 hammer_blockmap_t cundomap; 480 hammer_blockmap_t dundomap; 481 int64_t max_bytes __debugvar; 482 int64_t bytes; 483 484 cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 485 dundomap = &trans->rootvol->ondisk-> 486 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 487 488 if (dundomap->first_offset <= cundomap->next_offset) { 489 bytes = cundomap->next_offset - dundomap->first_offset; 490 } else { 491 bytes = cundomap->alloc_offset - dundomap->first_offset + 492 (cundomap->next_offset & HAMMER_OFF_LONG_MASK); 493 } 494 max_bytes = cundomap->alloc_offset & HAMMER_OFF_SHORT_MASK; 495 KKASSERT(bytes <= max_bytes); 496 return(bytes); 497 } 498 499 /* 500 * Return how much of the undo FIFO is available for new records. 501 */ 502 int64_t 503 hammer_undo_space(hammer_transaction_t trans) 504 { 505 hammer_blockmap_t rootmap; 506 int64_t max_bytes; 507 508 rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 509 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 510 return(max_bytes - hammer_undo_used(trans)); 511 } 512 513 int64_t 514 hammer_undo_max(hammer_mount_t hmp) 515 { 516 hammer_blockmap_t rootmap; 517 int64_t max_bytes; 518 519 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 520 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 521 522 return(max_bytes); 523 } 524 525 /* 526 * Returns 1 if the undo buffer should be reclaimed on release. The 527 * only undo buffer we do NOT want to reclaim is the one at the current 528 * append offset. 529 */ 530 int 531 hammer_undo_reclaim(hammer_io_t io) 532 { 533 hammer_blockmap_t undomap; 534 hammer_off_t next_offset; 535 536 undomap = &io->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 537 next_offset = undomap->next_offset & ~HAMMER_BUFMASK64; 538 if (((struct hammer_buffer *)io)->zoneX_offset == next_offset) 539 return(0); 540 return(1); 541 } 542 543 static int 544 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2) 545 { 546 if (node1->offset < node2->offset) 547 return(-1); 548 if (node1->offset > node2->offset) 549 return(1); 550 return(0); 551 } 552 553