1 /* 2 * This file is part of UBIFS. 3 * 4 * Copyright (C) 2006-2008 Nokia Corporation. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 as published by 8 * the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License along with 16 * this program; if not, write to the Free Software Foundation, Inc., 51 17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 * 19 * Authors: Artem Bityutskiy (Битюцкий Артём) 20 * Adrian Hunter 21 */ 22 23 /* This file implements reading and writing the master node */ 24 25 #include "ubifs.h" 26 27 /** 28 * scan_for_master - search the valid master node. 29 * @c: UBIFS file-system description object 30 * 31 * This function scans the master node LEBs and search for the latest master 32 * node. Returns zero in case of success and a negative error code in case of 33 * failure. 34 */ 35 static int scan_for_master(struct ubifs_info *c) 36 { 37 struct ubifs_scan_leb *sleb; 38 struct ubifs_scan_node *snod; 39 int lnum, offs = 0, nodes_cnt; 40 41 lnum = UBIFS_MST_LNUM; 42 43 sleb = ubifs_scan(c, lnum, 0, c->sbuf); 44 if (IS_ERR(sleb)) 45 return PTR_ERR(sleb); 46 nodes_cnt = sleb->nodes_cnt; 47 if (nodes_cnt > 0) { 48 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, 49 list); 50 if (snod->type != UBIFS_MST_NODE) 51 goto out; 52 memcpy(c->mst_node, snod->node, snod->len); 53 offs = snod->offs; 54 } 55 ubifs_scan_destroy(sleb); 56 57 lnum += 1; 58 59 sleb = ubifs_scan(c, lnum, 0, c->sbuf); 60 if (IS_ERR(sleb)) 61 return PTR_ERR(sleb); 62 if (sleb->nodes_cnt != nodes_cnt) 63 goto out; 64 if (!sleb->nodes_cnt) 65 goto out; 66 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list); 67 if (snod->type != UBIFS_MST_NODE) 68 goto out; 69 if (snod->offs != offs) 70 goto out; 71 if (memcmp((void *)c->mst_node + UBIFS_CH_SZ, 72 (void *)snod->node + UBIFS_CH_SZ, 73 UBIFS_MST_NODE_SZ - UBIFS_CH_SZ)) 74 goto out; 75 c->mst_offs = offs; 76 ubifs_scan_destroy(sleb); 77 return 0; 78 79 out: 80 ubifs_scan_destroy(sleb); 81 return -EINVAL; 82 } 83 84 /** 85 * validate_master - validate master node. 86 * @c: UBIFS file-system description object 87 * 88 * This function validates data which was read from master node. Returns zero 89 * if the data is all right and %-EINVAL if not. 90 */ 91 static int validate_master(const struct ubifs_info *c) 92 { 93 long long main_sz; 94 int err; 95 96 if (c->max_sqnum >= SQNUM_WATERMARK) { 97 err = 1; 98 goto out; 99 } 100 101 if (c->cmt_no >= c->max_sqnum) { 102 err = 2; 103 goto out; 104 } 105 106 if (c->highest_inum >= INUM_WATERMARK) { 107 err = 3; 108 goto out; 109 } 110 111 if (c->lhead_lnum < UBIFS_LOG_LNUM || 112 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs || 113 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size || 114 c->lhead_offs & (c->min_io_size - 1)) { 115 err = 4; 116 goto out; 117 } 118 119 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first || 120 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) { 121 err = 5; 122 goto out; 123 } 124 125 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len || 126 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) { 127 err = 6; 128 goto out; 129 } 130 131 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) { 132 err = 7; 133 goto out; 134 } 135 136 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first || 137 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 || 138 c->ihead_offs > c->leb_size || c->ihead_offs & 7) { 139 err = 8; 140 goto out; 141 } 142 143 main_sz = (long long)c->main_lebs * c->leb_size; 144 if (c->old_idx_sz & 7 || c->old_idx_sz >= main_sz) { 145 err = 9; 146 goto out; 147 } 148 149 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last || 150 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) { 151 err = 10; 152 goto out; 153 } 154 155 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last || 156 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size || 157 c->nhead_offs > c->leb_size) { 158 err = 11; 159 goto out; 160 } 161 162 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last || 163 c->ltab_offs < 0 || 164 c->ltab_offs + c->ltab_sz > c->leb_size) { 165 err = 12; 166 goto out; 167 } 168 169 if (c->big_lpt && (c->lsave_lnum < c->lpt_first || 170 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 || 171 c->lsave_offs + c->lsave_sz > c->leb_size)) { 172 err = 13; 173 goto out; 174 } 175 176 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) { 177 err = 14; 178 goto out; 179 } 180 181 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) { 182 err = 15; 183 goto out; 184 } 185 186 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) { 187 err = 16; 188 goto out; 189 } 190 191 if (c->lst.total_free < 0 || c->lst.total_free > main_sz || 192 c->lst.total_free & 7) { 193 err = 17; 194 goto out; 195 } 196 197 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) { 198 err = 18; 199 goto out; 200 } 201 202 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) { 203 err = 19; 204 goto out; 205 } 206 207 if (c->lst.total_free + c->lst.total_dirty + 208 c->lst.total_used > main_sz) { 209 err = 20; 210 goto out; 211 } 212 213 if (c->lst.total_dead + c->lst.total_dark + 214 c->lst.total_used + c->old_idx_sz > main_sz) { 215 err = 21; 216 goto out; 217 } 218 219 if (c->lst.total_dead < 0 || 220 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty || 221 c->lst.total_dead & 7) { 222 err = 22; 223 goto out; 224 } 225 226 if (c->lst.total_dark < 0 || 227 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty || 228 c->lst.total_dark & 7) { 229 err = 23; 230 goto out; 231 } 232 233 return 0; 234 235 out: 236 ubifs_err("bad master node at offset %d error %d", c->mst_offs, err); 237 dbg_dump_node(c, c->mst_node); 238 return -EINVAL; 239 } 240 241 /** 242 * ubifs_read_master - read master node. 243 * @c: UBIFS file-system description object 244 * 245 * This function finds and reads the master node during file-system mount. If 246 * the flash is empty, it creates default master node as well. Returns zero in 247 * case of success and a negative error code in case of failure. 248 */ 249 int ubifs_read_master(struct ubifs_info *c) 250 { 251 int err, old_leb_cnt; 252 253 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL); 254 if (!c->mst_node) 255 return -ENOMEM; 256 257 err = scan_for_master(c); 258 if (err) { 259 err = ubifs_recover_master_node(c); 260 if (err) 261 /* 262 * Note, we do not free 'c->mst_node' here because the 263 * unmount routine will take care of this. 264 */ 265 return err; 266 } 267 268 /* Make sure that the recovery flag is clear */ 269 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY); 270 271 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum); 272 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum); 273 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no); 274 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum); 275 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs); 276 c->zroot.len = le32_to_cpu(c->mst_node->root_len); 277 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum); 278 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum); 279 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum); 280 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs); 281 c->old_idx_sz = le64_to_cpu(c->mst_node->index_size); 282 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum); 283 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs); 284 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum); 285 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs); 286 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum); 287 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs); 288 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum); 289 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs); 290 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum); 291 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs); 292 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs); 293 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt); 294 c->lst.total_free = le64_to_cpu(c->mst_node->total_free); 295 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty); 296 c->lst.total_used = le64_to_cpu(c->mst_node->total_used); 297 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead); 298 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark); 299 300 c->calc_idx_sz = c->old_idx_sz; 301 302 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS)) 303 c->no_orphs = 1; 304 305 if (old_leb_cnt != c->leb_cnt) { 306 /* The file system has been resized */ 307 int growth = c->leb_cnt - old_leb_cnt; 308 309 if (c->leb_cnt < old_leb_cnt || 310 c->leb_cnt < UBIFS_MIN_LEB_CNT) { 311 ubifs_err("bad leb_cnt on master node"); 312 dbg_dump_node(c, c->mst_node); 313 return -EINVAL; 314 } 315 316 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs", 317 old_leb_cnt, c->leb_cnt); 318 c->lst.empty_lebs += growth; 319 c->lst.total_free += growth * (long long)c->leb_size; 320 c->lst.total_dark += growth * (long long)c->dark_wm; 321 322 /* 323 * Reflect changes back onto the master node. N.B. the master 324 * node gets written immediately whenever mounting (or 325 * remounting) in read-write mode, so we do not need to write it 326 * here. 327 */ 328 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt); 329 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs); 330 c->mst_node->total_free = cpu_to_le64(c->lst.total_free); 331 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark); 332 } 333 334 err = validate_master(c); 335 if (err) 336 return err; 337 338 err = dbg_old_index_check_init(c, &c->zroot); 339 340 return err; 341 } 342 343 /** 344 * ubifs_write_master - write master node. 345 * @c: UBIFS file-system description object 346 * 347 * This function writes the master node. The caller has to take the 348 * @c->mst_mutex lock before calling this function. Returns zero in case of 349 * success and a negative error code in case of failure. The master node is 350 * written twice to enable recovery. 351 */ 352 int ubifs_write_master(struct ubifs_info *c) 353 { 354 int err, lnum, offs, len; 355 356 if (c->ro_media) 357 return -EROFS; 358 359 lnum = UBIFS_MST_LNUM; 360 offs = c->mst_offs + c->mst_node_alsz; 361 len = UBIFS_MST_NODE_SZ; 362 363 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) { 364 err = ubifs_leb_unmap(c, lnum); 365 if (err) 366 return err; 367 offs = 0; 368 } 369 370 c->mst_offs = offs; 371 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum); 372 373 err = ubifs_write_node(c, c->mst_node, len, lnum, offs, UBI_SHORTTERM); 374 if (err) 375 return err; 376 377 lnum += 1; 378 379 if (offs == 0) { 380 err = ubifs_leb_unmap(c, lnum); 381 if (err) 382 return err; 383 } 384 err = ubifs_write_node(c, c->mst_node, len, lnum, offs, UBI_SHORTTERM); 385 386 return err; 387 } 388