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 * $DragonFly: src/sys/vfs/hammer/hammer_undo.c,v 1.20 2008/07/18 00:19:53 dillon Exp $ 35 */ 36 37 /* 38 * HAMMER undo - undo buffer/FIFO management. 39 */ 40 41 #include "hammer.h" 42 43 static int hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2); 44 45 RB_GENERATE2(hammer_und_rb_tree, hammer_undo, rb_node, 46 hammer_und_rb_compare, hammer_off_t, offset); 47 48 /* 49 * Convert a zone-3 undo offset into a zone-2 buffer offset. 50 */ 51 hammer_off_t 52 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp) 53 { 54 hammer_volume_t root_volume; 55 hammer_blockmap_t undomap; 56 hammer_off_t result_offset; 57 int i; 58 59 KKASSERT((zone3_off & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_UNDO); 60 root_volume = hammer_get_root_volume(hmp, errorp); 61 if (*errorp) 62 return(0); 63 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 64 KKASSERT(HAMMER_ZONE_DECODE(undomap->alloc_offset) == HAMMER_ZONE_UNDO_INDEX); 65 KKASSERT (zone3_off < undomap->alloc_offset); 66 67 i = (zone3_off & HAMMER_OFF_SHORT_MASK) / HAMMER_LARGEBLOCK_SIZE; 68 result_offset = root_volume->ondisk->vol0_undo_array[i] + 69 (zone3_off & HAMMER_LARGEBLOCK_MASK64); 70 71 hammer_rel_volume(root_volume, 0); 72 return(result_offset); 73 } 74 75 /* 76 * Generate an UNDO record for the block of data at the specified zone1 77 * or zone2 offset. 78 * 79 * The recovery code will execute UNDOs in reverse order, allowing overlaps. 80 * All the UNDOs are executed together so if we already laid one down we 81 * do not have to lay another one down for the same range. 82 */ 83 int 84 hammer_generate_undo(hammer_transaction_t trans, hammer_io_t io, 85 hammer_off_t zone_off, void *base, int len) 86 { 87 hammer_mount_t hmp; 88 hammer_volume_t root_volume; 89 hammer_blockmap_t undomap; 90 hammer_buffer_t buffer = NULL; 91 hammer_fifo_undo_t undo; 92 hammer_fifo_tail_t tail; 93 hammer_off_t next_offset; 94 int error; 95 int bytes; 96 97 hmp = trans->hmp; 98 99 /* 100 * Enter the offset into our undo history. If there is an existing 101 * undo we do not have to generate a new one. 102 */ 103 if (hammer_enter_undo_history(hmp, zone_off, len) == EALREADY) 104 return(0); 105 106 root_volume = trans->rootvol; 107 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 108 109 /* no undo recursion */ 110 hammer_modify_volume(NULL, root_volume, NULL, 0); 111 112 hammer_lock_ex(&hmp->undo_lock); 113 again: 114 /* 115 * Allocate space in the FIFO 116 */ 117 bytes = ((len + HAMMER_HEAD_ALIGN_MASK) & ~HAMMER_HEAD_ALIGN_MASK) + 118 sizeof(struct hammer_fifo_undo) + 119 sizeof(struct hammer_fifo_tail); 120 if (hammer_undo_space(trans) < bytes + HAMMER_BUFSIZE*2) 121 panic("hammer: insufficient undo FIFO space!"); 122 123 next_offset = undomap->next_offset; 124 125 /* 126 * Wrap next_offset 127 */ 128 if (undomap->next_offset == undomap->alloc_offset) { 129 next_offset = HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0); 130 undomap->next_offset = next_offset; 131 } 132 133 /* 134 * This is a tail-chasing FIFO, when we hit the start of a new 135 * buffer we don't have to read it in. 136 */ 137 if ((next_offset & HAMMER_BUFMASK) == 0) 138 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 139 else 140 undo = hammer_bread(hmp, next_offset, &error, &buffer); 141 if (error) 142 goto done; 143 144 hammer_modify_buffer(NULL, buffer, NULL, 0); 145 146 KKASSERT(undomap->next_offset == next_offset); 147 148 /* 149 * The FIFO entry would cross a buffer boundary, PAD to the end 150 * of the buffer and try again. Due to our data alignment, the 151 * worst case (smallest) PAD record is 8 bytes. PAD records only 152 * populate the first 8 bytes of hammer_fifo_head and the tail may 153 * be at the same offset as the head. 154 */ 155 if ((next_offset ^ (next_offset + bytes)) & ~HAMMER_BUFMASK64) { 156 bytes = HAMMER_BUFSIZE - ((int)next_offset & HAMMER_BUFMASK); 157 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 158 if ((void *)undo != (void *)tail) { 159 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 160 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 161 tail->tail_size = bytes; 162 } 163 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 164 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 165 undo->head.hdr_size = bytes; 166 /* NO CRC */ 167 undomap->next_offset += bytes; 168 hammer_modify_buffer_done(buffer); 169 goto again; 170 } 171 if (hammer_debug_general & 0x0080) 172 kprintf("undo %016llx %d %d\n", next_offset, bytes, len); 173 174 /* 175 * We're good, create the entry. 176 */ 177 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 178 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 179 undo->head.hdr_size = bytes; 180 undo->head.reserved01 = 0; 181 undo->head.hdr_crc = 0; 182 undo->undo_offset = zone_off; 183 undo->undo_data_bytes = len; 184 bcopy(base, undo + 1, len); 185 186 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 187 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 188 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 189 tail->tail_size = bytes; 190 191 KKASSERT(bytes >= sizeof(undo->head)); 192 undo->head.hdr_crc = crc32(undo, HAMMER_FIFO_HEAD_CRCOFF) ^ 193 crc32(&undo->head + 1, bytes - sizeof(undo->head)); 194 undomap->next_offset += bytes; 195 196 hammer_modify_buffer_done(buffer); 197 done: 198 hammer_modify_volume_done(root_volume); 199 hammer_unlock(&hmp->undo_lock); 200 201 if (buffer) 202 hammer_rel_buffer(buffer, 0); 203 return(error); 204 } 205 206 /* 207 * UNDO HISTORY API 208 * 209 * It is not necessary to layout an undo record for the same address space 210 * multiple times. Maintain a cache of recent undo's. 211 */ 212 213 /* 214 * Enter an undo into the history. Return EALREADY if the request completely 215 * covers a previous request. 216 */ 217 int 218 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes) 219 { 220 hammer_undo_t node; 221 hammer_undo_t onode; 222 223 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset); 224 if (node) { 225 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 226 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 227 if (bytes <= node->bytes) 228 return(EALREADY); 229 node->bytes = bytes; 230 return(0); 231 } 232 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) { 233 node = &hmp->undos[hmp->undo_alloc++]; 234 } else { 235 node = TAILQ_FIRST(&hmp->undo_lru_list); 236 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 237 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node); 238 } 239 node->offset = offset; 240 node->bytes = bytes; 241 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 242 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node); 243 KKASSERT(onode == NULL); 244 return(0); 245 } 246 247 void 248 hammer_clear_undo_history(hammer_mount_t hmp) 249 { 250 RB_INIT(&hmp->rb_undo_root); 251 TAILQ_INIT(&hmp->undo_lru_list); 252 hmp->undo_alloc = 0; 253 } 254 255 /* 256 * Return how much of the undo FIFO has been used 257 * 258 * The calculation includes undo FIFO space still reserved from a previous 259 * flush (because it will still be run on recovery if a crash occurs and 260 * we can't overwrite it yet). 261 */ 262 int64_t 263 hammer_undo_used(hammer_transaction_t trans) 264 { 265 hammer_blockmap_t cundomap; 266 hammer_blockmap_t dundomap; 267 int64_t max_bytes; 268 int64_t bytes; 269 270 cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 271 dundomap = &trans->rootvol->ondisk-> 272 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 273 274 if (dundomap->first_offset <= cundomap->next_offset) { 275 bytes = cundomap->next_offset - dundomap->first_offset; 276 } else { 277 bytes = cundomap->alloc_offset - dundomap->first_offset + 278 (cundomap->next_offset & HAMMER_OFF_LONG_MASK); 279 } 280 max_bytes = cundomap->alloc_offset & HAMMER_OFF_SHORT_MASK; 281 KKASSERT(bytes <= max_bytes); 282 return(bytes); 283 } 284 285 /* 286 * Return how much of the undo FIFO is available for new records. 287 */ 288 int64_t 289 hammer_undo_space(hammer_transaction_t trans) 290 { 291 hammer_blockmap_t rootmap; 292 int64_t max_bytes; 293 294 rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 295 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 296 return(max_bytes - hammer_undo_used(trans)); 297 } 298 299 int64_t 300 hammer_undo_max(hammer_mount_t hmp) 301 { 302 hammer_blockmap_t rootmap; 303 int64_t max_bytes; 304 305 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 306 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 307 308 return(max_bytes); 309 } 310 311 static int 312 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2) 313 { 314 if (node1->offset < node2->offset) 315 return(-1); 316 if (node1->offset > node2->offset) 317 return(1); 318 return(0); 319 } 320 321