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: Adrian Hunter 20 * Artem Bityutskiy (Битюцкий Артём) 21 */ 22 23 /* 24 * This file implements the scan which is a general-purpose function for 25 * determining what nodes are in an eraseblock. The scan is used to replay the 26 * journal, to do garbage collection. for the TNC in-the-gaps method, and by 27 * debugging functions. 28 */ 29 30 #include "ubifs.h" 31 32 /** 33 * scan_padding_bytes - scan for padding bytes. 34 * @buf: buffer to scan 35 * @len: length of buffer 36 * 37 * This function returns the number of padding bytes on success and 38 * %SCANNED_GARBAGE on failure. 39 */ 40 static int scan_padding_bytes(void *buf, int len) 41 { 42 int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len); 43 uint8_t *p = buf; 44 45 dbg_scan("not a node"); 46 47 while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE) 48 pad_len += 1; 49 50 if (!pad_len || (pad_len & 7)) 51 return SCANNED_GARBAGE; 52 53 dbg_scan("%d padding bytes", pad_len); 54 55 return pad_len; 56 } 57 58 /** 59 * ubifs_scan_a_node - scan for a node or padding. 60 * @c: UBIFS file-system description object 61 * @buf: buffer to scan 62 * @len: length of buffer 63 * @lnum: logical eraseblock number 64 * @offs: offset within the logical eraseblock 65 * @quiet: print no messages 66 * 67 * This function returns a scanning code to indicate what was scanned. 68 */ 69 int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum, 70 int offs, int quiet) 71 { 72 struct ubifs_ch *ch = buf; 73 uint32_t magic; 74 75 magic = le32_to_cpu(ch->magic); 76 77 if (magic == 0xFFFFFFFF) { 78 dbg_scan("hit empty space"); 79 return SCANNED_EMPTY_SPACE; 80 } 81 82 if (magic != UBIFS_NODE_MAGIC) 83 return scan_padding_bytes(buf, len); 84 85 if (len < UBIFS_CH_SZ) 86 return SCANNED_GARBAGE; 87 88 dbg_scan("scanning %s", dbg_ntype(ch->node_type)); 89 90 if (ubifs_check_node(c, buf, lnum, offs, quiet, 1)) 91 return SCANNED_A_CORRUPT_NODE; 92 93 if (ch->node_type == UBIFS_PAD_NODE) { 94 struct ubifs_pad_node *pad = buf; 95 int pad_len = le32_to_cpu(pad->pad_len); 96 int node_len = le32_to_cpu(ch->len); 97 98 /* Validate the padding node */ 99 if (pad_len < 0 || 100 offs + node_len + pad_len > c->leb_size) { 101 if (!quiet) { 102 ubifs_err("bad pad node at LEB %d:%d", 103 lnum, offs); 104 dbg_dump_node(c, pad); 105 } 106 return SCANNED_A_BAD_PAD_NODE; 107 } 108 109 /* Make the node pads to 8-byte boundary */ 110 if ((node_len + pad_len) & 7) { 111 if (!quiet) 112 dbg_err("bad padding length %d - %d", 113 offs, offs + node_len + pad_len); 114 return SCANNED_A_BAD_PAD_NODE; 115 } 116 117 dbg_scan("%d bytes padded, offset now %d", 118 pad_len, ALIGN(offs + node_len + pad_len, 8)); 119 120 return node_len + pad_len; 121 } 122 123 return SCANNED_A_NODE; 124 } 125 126 /** 127 * ubifs_start_scan - create LEB scanning information at start of scan. 128 * @c: UBIFS file-system description object 129 * @lnum: logical eraseblock number 130 * @offs: offset to start at (usually zero) 131 * @sbuf: scan buffer (must be c->leb_size) 132 * 133 * This function returns %0 on success and a negative error code on failure. 134 */ 135 struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum, 136 int offs, void *sbuf) 137 { 138 struct ubifs_scan_leb *sleb; 139 int err; 140 141 dbg_scan("scan LEB %d:%d", lnum, offs); 142 143 sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS); 144 if (!sleb) 145 return ERR_PTR(-ENOMEM); 146 147 sleb->lnum = lnum; 148 INIT_LIST_HEAD(&sleb->nodes); 149 sleb->buf = sbuf; 150 151 err = ubi_read(c->ubi, lnum, sbuf + offs, offs, c->leb_size - offs); 152 if (err && err != -EBADMSG) { 153 ubifs_err("cannot read %d bytes from LEB %d:%d," 154 " error %d", c->leb_size - offs, lnum, offs, err); 155 kfree(sleb); 156 return ERR_PTR(err); 157 } 158 159 if (err == -EBADMSG) 160 sleb->ecc = 1; 161 162 return sleb; 163 } 164 165 /** 166 * ubifs_end_scan - update LEB scanning information at end of scan. 167 * @c: UBIFS file-system description object 168 * @sleb: scanning information 169 * @lnum: logical eraseblock number 170 * @offs: offset to start at (usually zero) 171 * 172 * This function returns %0 on success and a negative error code on failure. 173 */ 174 void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb, 175 int lnum, int offs) 176 { 177 lnum = lnum; 178 dbg_scan("stop scanning LEB %d at offset %d", lnum, offs); 179 ubifs_assert(offs % c->min_io_size == 0); 180 181 sleb->endpt = ALIGN(offs, c->min_io_size); 182 } 183 184 /** 185 * ubifs_add_snod - add a scanned node to LEB scanning information. 186 * @c: UBIFS file-system description object 187 * @sleb: scanning information 188 * @buf: buffer containing node 189 * @offs: offset of node on flash 190 * 191 * This function returns %0 on success and a negative error code on failure. 192 */ 193 int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb, 194 void *buf, int offs) 195 { 196 struct ubifs_ch *ch = buf; 197 struct ubifs_ino_node *ino = buf; 198 struct ubifs_scan_node *snod; 199 200 snod = kzalloc(sizeof(struct ubifs_scan_node), GFP_NOFS); 201 if (!snod) 202 return -ENOMEM; 203 204 snod->sqnum = le64_to_cpu(ch->sqnum); 205 snod->type = ch->node_type; 206 snod->offs = offs; 207 snod->len = le32_to_cpu(ch->len); 208 snod->node = buf; 209 210 switch (ch->node_type) { 211 case UBIFS_INO_NODE: 212 case UBIFS_DENT_NODE: 213 case UBIFS_XENT_NODE: 214 case UBIFS_DATA_NODE: 215 case UBIFS_TRUN_NODE: 216 /* 217 * The key is in the same place in all keyed 218 * nodes. 219 */ 220 key_read(c, &ino->key, &snod->key); 221 break; 222 } 223 list_add_tail(&snod->list, &sleb->nodes); 224 sleb->nodes_cnt += 1; 225 return 0; 226 } 227 228 /** 229 * ubifs_scanned_corruption - print information after UBIFS scanned corruption. 230 * @c: UBIFS file-system description object 231 * @lnum: LEB number of corruption 232 * @offs: offset of corruption 233 * @buf: buffer containing corruption 234 */ 235 void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs, 236 void *buf) 237 { 238 int len; 239 240 ubifs_err("corruption at LEB %d:%d", lnum, offs); 241 if (dbg_failure_mode) 242 return; 243 len = c->leb_size - offs; 244 if (len > 8192) 245 len = 8192; 246 dbg_err("first %d bytes from LEB %d:%d", len, lnum, offs); 247 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1); 248 } 249 250 /** 251 * ubifs_scan - scan a logical eraseblock. 252 * @c: UBIFS file-system description object 253 * @lnum: logical eraseblock number 254 * @offs: offset to start at (usually zero) 255 * @sbuf: scan buffer (must be of @c->leb_size bytes in size) 256 * @quiet: print no messages 257 * 258 * This function scans LEB number @lnum and returns complete information about 259 * its contents. Returns the scaned information in case of success and, 260 * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case 261 * of failure. 262 * 263 * If @quiet is non-zero, this function does not print large and scary 264 * error messages and flash dumps in case of errors. 265 */ 266 struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum, 267 int offs, void *sbuf, int quiet) 268 { 269 void *buf = sbuf + offs; 270 int err, len = c->leb_size - offs; 271 struct ubifs_scan_leb *sleb; 272 273 sleb = ubifs_start_scan(c, lnum, offs, sbuf); 274 if (IS_ERR(sleb)) 275 return sleb; 276 277 while (len >= 8) { 278 struct ubifs_ch *ch = buf; 279 int node_len, ret; 280 281 dbg_scan("look at LEB %d:%d (%d bytes left)", 282 lnum, offs, len); 283 284 cond_resched(); 285 286 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet); 287 if (ret > 0) { 288 /* Padding bytes or a valid padding node */ 289 offs += ret; 290 buf += ret; 291 len -= ret; 292 continue; 293 } 294 295 if (ret == SCANNED_EMPTY_SPACE) 296 /* Empty space is checked later */ 297 break; 298 299 switch (ret) { 300 case SCANNED_GARBAGE: 301 dbg_err("garbage"); 302 goto corrupted; 303 case SCANNED_A_NODE: 304 break; 305 case SCANNED_A_CORRUPT_NODE: 306 case SCANNED_A_BAD_PAD_NODE: 307 dbg_err("bad node"); 308 goto corrupted; 309 default: 310 dbg_err("unknown"); 311 err = -EINVAL; 312 goto error; 313 } 314 315 err = ubifs_add_snod(c, sleb, buf, offs); 316 if (err) 317 goto error; 318 319 node_len = ALIGN(le32_to_cpu(ch->len), 8); 320 offs += node_len; 321 buf += node_len; 322 len -= node_len; 323 } 324 325 if (offs % c->min_io_size) { 326 if (!quiet) 327 ubifs_err("empty space starts at non-aligned offset %d", 328 offs); 329 goto corrupted;; 330 } 331 332 ubifs_end_scan(c, sleb, lnum, offs); 333 334 for (; len > 4; offs += 4, buf = buf + 4, len -= 4) 335 if (*(uint32_t *)buf != 0xffffffff) 336 break; 337 for (; len; offs++, buf++, len--) 338 if (*(uint8_t *)buf != 0xff) { 339 if (!quiet) 340 ubifs_err("corrupt empty space at LEB %d:%d", 341 lnum, offs); 342 goto corrupted; 343 } 344 345 return sleb; 346 347 corrupted: 348 if (!quiet) { 349 ubifs_scanned_corruption(c, lnum, offs, buf); 350 ubifs_err("LEB %d scanning failed", lnum); 351 } 352 err = -EUCLEAN; 353 ubifs_scan_destroy(sleb); 354 return ERR_PTR(err); 355 356 error: 357 ubifs_err("LEB %d scanning failed, error %d", lnum, err); 358 ubifs_scan_destroy(sleb); 359 return ERR_PTR(err); 360 } 361 362 /** 363 * ubifs_scan_destroy - destroy LEB scanning information. 364 * @sleb: scanning information to free 365 */ 366 void ubifs_scan_destroy(struct ubifs_scan_leb *sleb) 367 { 368 struct ubifs_scan_node *node; 369 struct list_head *head; 370 371 head = &sleb->nodes; 372 while (!list_empty(head)) { 373 node = list_entry(head->next, struct ubifs_scan_node, list); 374 list_del(&node->list); 375 kfree(node); 376 } 377 kfree(sleb); 378 } 379