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 1.18 2008/06/27 20:56:59 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 hkprintf("undo zone's next_offset wrapped\n"); 132 } 133 134 /* 135 * This is a tail-chasing FIFO, when we hit the start of a new 136 * buffer we don't have to read it in. 137 */ 138 if ((next_offset & HAMMER_BUFMASK) == 0) 139 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 140 else 141 undo = hammer_bread(hmp, next_offset, &error, &buffer); 142 hammer_modify_buffer(NULL, buffer, NULL, 0); 143 144 KKASSERT(undomap->next_offset == next_offset); 145 146 /* 147 * The FIFO entry would cross a buffer boundary, PAD to the end 148 * of the buffer and try again. Due to our data alignment, the 149 * worst case (smallest) PAD record is 8 bytes. PAD records only 150 * populate the first 8 bytes of hammer_fifo_head and the tail may 151 * be at the same offset as the head. 152 */ 153 if ((next_offset ^ (next_offset + bytes)) & ~HAMMER_BUFMASK64) { 154 bytes = HAMMER_BUFSIZE - ((int)next_offset & HAMMER_BUFMASK); 155 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 156 if ((void *)undo != (void *)tail) { 157 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 158 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 159 tail->tail_size = bytes; 160 } 161 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 162 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 163 undo->head.hdr_size = bytes; 164 /* NO CRC */ 165 undomap->next_offset += bytes; 166 hammer_modify_buffer_done(buffer); 167 goto again; 168 } 169 if (hammer_debug_general & 0x0080) 170 kprintf("undo %016llx %d %d\n", next_offset, bytes, len); 171 172 /* 173 * We're good, create the entry. 174 */ 175 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 176 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 177 undo->head.hdr_size = bytes; 178 undo->head.reserved01 = 0; 179 undo->head.hdr_crc = 0; 180 undo->undo_offset = zone_off; 181 undo->undo_data_bytes = len; 182 bcopy(base, undo + 1, len); 183 184 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 185 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 186 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 187 tail->tail_size = bytes; 188 189 KKASSERT(bytes >= sizeof(undo->head)); 190 undo->head.hdr_crc = crc32(undo, HAMMER_FIFO_HEAD_CRCOFF) ^ 191 crc32(&undo->head + 1, bytes - sizeof(undo->head)); 192 undomap->next_offset += bytes; 193 194 hammer_modify_buffer_done(buffer); 195 hammer_modify_volume_done(root_volume); 196 197 hammer_unlock(&hmp->undo_lock); 198 199 if (buffer) 200 hammer_rel_buffer(buffer, 0); 201 return(error); 202 } 203 204 /* 205 * UNDO HISTORY API 206 * 207 * It is not necessary to layout an undo record for the same address space 208 * multiple times. Maintain a cache of recent undo's. 209 */ 210 211 /* 212 * Enter an undo into the history. Return EALREADY if the request completely 213 * covers a previous request. 214 */ 215 int 216 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes) 217 { 218 hammer_undo_t node; 219 hammer_undo_t onode; 220 221 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset); 222 if (node) { 223 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 224 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 225 if (bytes <= node->bytes) 226 return(EALREADY); 227 node->bytes = bytes; 228 return(0); 229 } 230 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) { 231 node = &hmp->undos[hmp->undo_alloc++]; 232 } else { 233 node = TAILQ_FIRST(&hmp->undo_lru_list); 234 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 235 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node); 236 } 237 node->offset = offset; 238 node->bytes = bytes; 239 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 240 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node); 241 KKASSERT(onode == NULL); 242 return(0); 243 } 244 245 void 246 hammer_clear_undo_history(hammer_mount_t hmp) 247 { 248 RB_INIT(&hmp->rb_undo_root); 249 TAILQ_INIT(&hmp->undo_lru_list); 250 hmp->undo_alloc = 0; 251 } 252 253 /* 254 * Return how much of the undo FIFO has been used 255 * 256 * The calculation includes undo FIFO space still reserved from a previous 257 * flush (because it will still be run on recovery if a crash occurs and 258 * we can't overwrite it yet). 259 */ 260 int64_t 261 hammer_undo_used(hammer_transaction_t trans) 262 { 263 hammer_blockmap_t cundomap; 264 hammer_blockmap_t dundomap; 265 int64_t max_bytes; 266 int64_t bytes; 267 268 cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 269 dundomap = &trans->rootvol->ondisk-> 270 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 271 272 if (dundomap->first_offset <= cundomap->next_offset) { 273 bytes = cundomap->next_offset - dundomap->first_offset; 274 } else { 275 bytes = cundomap->alloc_offset - dundomap->first_offset + 276 (cundomap->next_offset & HAMMER_OFF_LONG_MASK); 277 } 278 max_bytes = cundomap->alloc_offset & HAMMER_OFF_SHORT_MASK; 279 KKASSERT(bytes <= max_bytes); 280 return(bytes); 281 } 282 283 /* 284 * Return how much of the undo FIFO is available for new records. 285 */ 286 int64_t 287 hammer_undo_space(hammer_transaction_t trans) 288 { 289 hammer_blockmap_t rootmap; 290 int64_t max_bytes; 291 292 rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 293 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 294 return(max_bytes - hammer_undo_used(trans)); 295 } 296 297 int64_t 298 hammer_undo_max(hammer_mount_t hmp) 299 { 300 hammer_blockmap_t rootmap; 301 int64_t max_bytes; 302 303 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 304 max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK; 305 306 return(max_bytes); 307 } 308 309 static int 310 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2) 311 { 312 if (node1->offset < node2->offset) 313 return(-1); 314 if (node1->offset > node2->offset) 315 return(1); 316 return(0); 317 } 318 319