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 64 KKASSERT(hammer_is_zone_undo(zone3_off)); 65 root_volume = hammer_get_root_volume(hmp, errorp); 66 if (*errorp) 67 return(0); 68 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 69 KKASSERT(hammer_is_zone_undo(undomap->alloc_offset)); 70 KKASSERT(zone3_off < undomap->alloc_offset); 71 72 result_offset = hammer_xlate_to_undo(root_volume->ondisk, zone3_off); 73 74 hammer_rel_volume(root_volume, 0); 75 return(result_offset); 76 } 77 78 /* 79 * Generate UNDO record(s) for the block of data at the specified zone1 80 * or zone2 offset. 81 * 82 * The recovery code will execute UNDOs in reverse order, allowing overlaps. 83 * All the UNDOs are executed together so if we already laid one down we 84 * do not have to lay another one down for the same range. 85 * 86 * For HAMMER version 4+ UNDO a 512 byte boundary is enforced and a PAD 87 * will be laid down for any unused space. UNDO FIFO media structures 88 * will implement the hdr_seq field (it used to be reserved01), and 89 * both flush and recovery mechanics will be very different. 90 * 91 * WARNING! See also hammer_generate_redo() in hammer_redo.c 92 */ 93 int 94 hammer_generate_undo(hammer_transaction_t trans, 95 hammer_off_t zone_off, void *base, int len) 96 { 97 hammer_mount_t hmp; 98 hammer_volume_t root_volume; 99 hammer_blockmap_t undomap; 100 hammer_buffer_t buffer = NULL; 101 hammer_fifo_undo_t undo; 102 hammer_fifo_tail_t tail; 103 hammer_off_t next_offset; 104 int error; 105 int bytes; 106 int n; 107 108 hmp = trans->hmp; 109 110 /* 111 * A SYNC record may be required before we can lay down a general 112 * UNDO. This ensures that the nominal recovery span contains 113 * at least one SYNC record telling the recovery code how far 114 * out-of-span it must go to run the REDOs. 115 */ 116 if ((hmp->flags & HAMMER_MOUNT_REDO_SYNC) == 0 && 117 hmp->version >= HAMMER_VOL_VERSION_FOUR) { 118 hammer_generate_redo_sync(trans); 119 } 120 121 /* 122 * Enter the offset into our undo history. If there is an existing 123 * undo we do not have to generate a new one. 124 */ 125 if (hammer_enter_undo_history(hmp, zone_off, len) == EALREADY) 126 return(0); 127 128 root_volume = trans->rootvol; 129 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 130 131 /* no undo recursion */ 132 hammer_modify_volume_noundo(NULL, root_volume); 133 hammer_lock_ex(&hmp->undo_lock); 134 135 /* undo had better not roll over (loose test) */ 136 if (hammer_undo_space(trans) < len + HAMMER_BUFSIZE*3) 137 hpanic("insufficient UNDO/REDO FIFO space for undo!"); 138 139 /* 140 * Loop until the undo for the entire range has been laid down. 141 */ 142 while (len) { 143 /* 144 * Fetch the layout offset in the UNDO FIFO, wrap it as 145 * necessary. 146 */ 147 if (undomap->next_offset == undomap->alloc_offset) 148 undomap->next_offset = HAMMER_ENCODE_UNDO(0); 149 next_offset = undomap->next_offset; 150 151 /* 152 * This is a tail-chasing FIFO, when we hit the start of a new 153 * buffer we don't have to read it in. 154 */ 155 if ((next_offset & HAMMER_BUFMASK) == 0) { 156 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 157 hammer_format_undo(undo, hmp->undo_seqno ^ 0x40000000); 158 } else { 159 undo = hammer_bread(hmp, next_offset, &error, &buffer); 160 } 161 if (error) 162 break; 163 /* no undo recursion */ 164 hammer_modify_buffer_noundo(NULL, buffer); 165 166 /* 167 * Calculate how big a media structure fits up to the next 168 * alignment point and how large a data payload we can 169 * accomodate. 170 * 171 * If n calculates to 0 or negative there is no room for 172 * anything but a PAD. 173 */ 174 bytes = HAMMER_UNDO_ALIGN - 175 ((int)next_offset & HAMMER_UNDO_MASK); 176 n = bytes - 177 (int)sizeof(struct hammer_fifo_undo) - 178 (int)sizeof(struct hammer_fifo_tail); 179 180 /* 181 * If available space is insufficient for any payload 182 * we have to lay down a PAD. 183 * 184 * The minimum PAD is 8 bytes and the head and tail will 185 * overlap each other in that case. PADs do not have 186 * sequence numbers or CRCs. 187 * 188 * A PAD may not start on a boundary. That is, every 189 * 512-byte block in the UNDO/REDO FIFO must begin with 190 * a record containing a sequence number. 191 */ 192 if (n <= 0) { 193 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 194 KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0); 195 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 196 if ((void *)undo != (void *)tail) { 197 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 198 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 199 tail->tail_size = bytes; 200 } 201 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 202 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 203 undo->head.hdr_size = bytes; 204 /* NO CRC OR SEQ NO */ 205 undomap->next_offset += bytes; 206 hammer_modify_buffer_done(buffer); 207 hammer_stats_undo += bytes; 208 continue; 209 } 210 211 /* 212 * Calculate the actual payload and recalculate the size 213 * of the media structure as necessary. 214 */ 215 if (n > len) { 216 n = len; 217 bytes = HAMMER_HEAD_DOALIGN(n) + 218 (int)sizeof(struct hammer_fifo_undo) + 219 (int)sizeof(struct hammer_fifo_tail); 220 } 221 if (hammer_debug_general & 0x0080) { 222 hdkprintf("undo %016jx %d %d\n", 223 (intmax_t)next_offset, bytes, n); 224 } 225 226 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 227 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 228 undo->head.hdr_size = bytes; 229 undo->head.hdr_seq = hmp->undo_seqno++; 230 undo->head.hdr_crc = 0; 231 undo->undo_offset = zone_off; 232 undo->undo_data_bytes = n; 233 bcopy(base, undo + 1, n); 234 235 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 236 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 237 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 238 tail->tail_size = bytes; 239 240 KKASSERT(bytes >= sizeof(undo->head)); 241 hammer_crc_set_fifo_head(&undo->head, bytes); 242 undomap->next_offset += bytes; 243 hammer_stats_undo += bytes; 244 245 /* 246 * Before we finish off the buffer we have to deal with any 247 * junk between the end of the media structure we just laid 248 * down and the UNDO alignment boundary. We do this by laying 249 * down a dummy PAD. Even though we will probably overwrite 250 * it almost immediately we have to do this so recovery runs 251 * can iterate the UNDO space without having to depend on 252 * the indices in the volume header. 253 * 254 * This dummy PAD will be overwritten on the next undo so 255 * we do not adjust undomap->next_offset. 256 */ 257 bytes = HAMMER_UNDO_ALIGN - 258 ((int)undomap->next_offset & HAMMER_UNDO_MASK); 259 if (bytes != HAMMER_UNDO_ALIGN) { 260 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 261 undo = (void *)(tail + 1); 262 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 263 if ((void *)undo != (void *)tail) { 264 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 265 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 266 tail->tail_size = bytes; 267 } 268 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 269 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 270 undo->head.hdr_size = bytes; 271 /* NO CRC OR SEQ NO */ 272 } 273 hammer_modify_buffer_done(buffer); 274 275 /* 276 * Adjust for loop 277 */ 278 len -= n; 279 base = (char *)base + n; 280 zone_off += n; 281 } 282 hammer_modify_volume_done(root_volume); 283 hammer_unlock(&hmp->undo_lock); 284 285 if (buffer) 286 hammer_rel_buffer(buffer, 0); 287 return(error); 288 } 289 290 /* 291 * Preformat a new UNDO block. We could read the old one in but we get 292 * better performance if we just pre-format a new one. 293 * 294 * The recovery code always works forwards so the caller just makes sure the 295 * seqno is not contiguous with prior UNDOs or ancient UNDOs now being 296 * overwritten. 297 * 298 * The preformatted UNDO headers use the smallest possible sector size 299 * (512) to ensure that any missed media writes are caught. 300 * 301 * NOTE: Also used by the REDO code. 302 */ 303 void 304 hammer_format_undo(void *base, uint32_t seqno) 305 { 306 hammer_fifo_head_t head; 307 hammer_fifo_tail_t tail; 308 int i; 309 int bytes = HAMMER_UNDO_ALIGN; 310 311 bzero(base, HAMMER_BUFSIZE); 312 313 for (i = 0; i < HAMMER_BUFSIZE; i += bytes) { 314 head = (void *)((char *)base + i); 315 tail = (void *)((char *)head + bytes - sizeof(*tail)); 316 317 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 318 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 319 head->hdr_size = bytes; 320 head->hdr_seq = seqno++; 321 head->hdr_crc = 0; 322 323 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 324 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 325 tail->tail_size = bytes; 326 327 hammer_crc_set_fifo_head(head, bytes); 328 } 329 } 330 331 /* 332 * HAMMER version 4+ conversion support. 333 * 334 * Convert a HAMMER version < 4 UNDO FIFO area to a 4+ UNDO FIFO area. 335 * The 4+ UNDO FIFO area is backwards compatible. The conversion is 336 * needed to initialize the sequence space and place headers on the 337 * new 512-byte undo boundary. 338 */ 339 int 340 hammer_upgrade_undo_4(hammer_transaction_t trans) 341 { 342 hammer_mount_t hmp; 343 hammer_volume_t root_volume; 344 hammer_blockmap_t undomap; 345 hammer_buffer_t buffer = NULL; 346 hammer_fifo_head_t head; 347 hammer_fifo_tail_t tail; 348 hammer_off_t next_offset; 349 uint32_t seqno; 350 int error; 351 int bytes; 352 353 hmp = trans->hmp; 354 355 root_volume = trans->rootvol; 356 357 /* no undo recursion */ 358 hammer_lock_ex(&hmp->undo_lock); 359 hammer_modify_volume_noundo(NULL, root_volume); 360 361 /* 362 * Adjust the in-core undomap and the on-disk undomap. 363 */ 364 next_offset = HAMMER_ENCODE_UNDO(0); 365 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 366 undomap->next_offset = next_offset; 367 undomap->first_offset = next_offset; 368 369 undomap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 370 undomap->next_offset = next_offset; 371 undomap->first_offset = next_offset; 372 373 /* 374 * Loop over the entire UNDO space creating DUMMY entries. Sequence 375 * numbers are assigned. 376 */ 377 seqno = 0; 378 bytes = HAMMER_UNDO_ALIGN; 379 380 while (next_offset != undomap->alloc_offset) { 381 head = hammer_bnew(hmp, next_offset, &error, &buffer); 382 if (error) 383 break; 384 hammer_modify_buffer_noundo(NULL, buffer); 385 tail = (void *)((char *)head + bytes - sizeof(*tail)); 386 387 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 388 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 389 head->hdr_size = bytes; 390 head->hdr_seq = seqno; 391 head->hdr_crc = 0; 392 393 tail = (void *)((char *)head + bytes - sizeof(*tail)); 394 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 395 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 396 tail->tail_size = bytes; 397 398 hammer_crc_set_fifo_head(head, bytes); 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 hmkprintf(hmp, "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 HAMMER_OFF_LONG_ENCODE(cundomap->next_offset); 493 } 494 max_bytes = HAMMER_OFF_SHORT_ENCODE(cundomap->alloc_offset); 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 = HAMMER_OFF_SHORT_ENCODE(rootmap->alloc_offset); 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 = HAMMER_OFF_SHORT_ENCODE(rootmap->alloc_offset); 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 (HAMMER_ITOB(io)->zoneX_offset == next_offset) 539 return(0); 540 return(1); 541 } 542