367 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * This file is part of UBIFS.4 *5 * Copyright (C) 2006-2008 Nokia Corporation6 *7 * Authors: Adrian Hunter8 * Artem Bityutskiy (Битюцкий Артём)9 */10 11/*12 * This file implements the scan which is a general-purpose function for13 * determining what nodes are in an eraseblock. The scan is used to replay the14 * journal, to do garbage collection. for the TNC in-the-gaps method, and by15 * debugging functions.16 */17 18#include "ubifs.h"19 20/**21 * scan_padding_bytes - scan for padding bytes.22 * @buf: buffer to scan23 * @len: length of buffer24 *25 * This function returns the number of padding bytes on success and26 * %SCANNED_GARBAGE on failure.27 */28static int scan_padding_bytes(void *buf, int len)29{30 int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);31 uint8_t *p = buf;32 33 dbg_scan("not a node");34 35 while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)36 pad_len += 1;37 38 if (!pad_len || (pad_len & 7))39 return SCANNED_GARBAGE;40 41 dbg_scan("%d padding bytes", pad_len);42 43 return pad_len;44}45 46/**47 * ubifs_scan_a_node - scan for a node or padding.48 * @c: UBIFS file-system description object49 * @buf: buffer to scan50 * @len: length of buffer51 * @lnum: logical eraseblock number52 * @offs: offset within the logical eraseblock53 * @quiet: print no messages54 *55 * This function returns a scanning code to indicate what was scanned.56 */57int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,58 int offs, int quiet)59{60 struct ubifs_ch *ch = buf;61 uint32_t magic;62 63 magic = le32_to_cpu(ch->magic);64 65 if (magic == 0xFFFFFFFF) {66 dbg_scan("hit empty space at LEB %d:%d", lnum, offs);67 return SCANNED_EMPTY_SPACE;68 }69 70 if (magic != UBIFS_NODE_MAGIC)71 return scan_padding_bytes(buf, len);72 73 if (len < UBIFS_CH_SZ)74 return SCANNED_GARBAGE;75 76 dbg_scan("scanning %s at LEB %d:%d",77 dbg_ntype(ch->node_type), lnum, offs);78 79 if (ubifs_check_node(c, buf, len, lnum, offs, quiet, 1))80 return SCANNED_A_CORRUPT_NODE;81 82 if (ch->node_type == UBIFS_PAD_NODE) {83 struct ubifs_pad_node *pad = buf;84 int pad_len = le32_to_cpu(pad->pad_len);85 int node_len = le32_to_cpu(ch->len);86 87 /* Validate the padding node */88 if (pad_len < 0 ||89 offs + node_len + pad_len > c->leb_size) {90 if (!quiet) {91 ubifs_err(c, "bad pad node at LEB %d:%d",92 lnum, offs);93 ubifs_dump_node(c, pad, len);94 }95 return SCANNED_A_BAD_PAD_NODE;96 }97 98 /* Make the node pads to 8-byte boundary */99 if ((node_len + pad_len) & 7) {100 if (!quiet)101 ubifs_err(c, "bad padding length %d - %d",102 offs, offs + node_len + pad_len);103 return SCANNED_A_BAD_PAD_NODE;104 }105 106 dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len,107 lnum, offs, ALIGN(offs + node_len + pad_len, 8));108 109 return node_len + pad_len;110 }111 112 return SCANNED_A_NODE;113}114 115/**116 * ubifs_start_scan - create LEB scanning information at start of scan.117 * @c: UBIFS file-system description object118 * @lnum: logical eraseblock number119 * @offs: offset to start at (usually zero)120 * @sbuf: scan buffer (must be c->leb_size)121 *122 * This function returns the scanned information on success and a negative error123 * code on failure.124 */125struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,126 int offs, void *sbuf)127{128 struct ubifs_scan_leb *sleb;129 int err;130 131 dbg_scan("scan LEB %d:%d", lnum, offs);132 133 sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);134 if (!sleb)135 return ERR_PTR(-ENOMEM);136 137 sleb->lnum = lnum;138 INIT_LIST_HEAD(&sleb->nodes);139 sleb->buf = sbuf;140 141 err = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);142 if (err && err != -EBADMSG) {143 ubifs_err(c, "cannot read %d bytes from LEB %d:%d, error %d",144 c->leb_size - offs, lnum, offs, err);145 kfree(sleb);146 return ERR_PTR(err);147 }148 149 /*150 * Note, we ignore integrity errors (EBASMSG) because all the nodes are151 * protected by CRC checksums.152 */153 return sleb;154}155 156/**157 * ubifs_end_scan - update LEB scanning information at end of scan.158 * @c: UBIFS file-system description object159 * @sleb: scanning information160 * @lnum: logical eraseblock number161 * @offs: offset to start at (usually zero)162 */163void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,164 int lnum, int offs)165{166 dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);167 ubifs_assert(c, offs % c->min_io_size == 0);168 169 sleb->endpt = ALIGN(offs, c->min_io_size);170}171 172/**173 * ubifs_add_snod - add a scanned node to LEB scanning information.174 * @c: UBIFS file-system description object175 * @sleb: scanning information176 * @buf: buffer containing node177 * @offs: offset of node on flash178 *179 * This function returns %0 on success and a negative error code on failure.180 */181int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,182 void *buf, int offs)183{184 struct ubifs_ch *ch = buf;185 struct ubifs_ino_node *ino = buf;186 struct ubifs_scan_node *snod;187 188 snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);189 if (!snod)190 return -ENOMEM;191 192 snod->sqnum = le64_to_cpu(ch->sqnum);193 snod->type = ch->node_type;194 snod->offs = offs;195 snod->len = le32_to_cpu(ch->len);196 snod->node = buf;197 198 switch (ch->node_type) {199 case UBIFS_INO_NODE:200 case UBIFS_DENT_NODE:201 case UBIFS_XENT_NODE:202 case UBIFS_DATA_NODE:203 /*204 * The key is in the same place in all keyed205 * nodes.206 */207 key_read(c, &ino->key, &snod->key);208 break;209 default:210 invalid_key_init(c, &snod->key);211 break;212 }213 list_add_tail(&snod->list, &sleb->nodes);214 sleb->nodes_cnt += 1;215 return 0;216}217 218/**219 * ubifs_scanned_corruption - print information after UBIFS scanned corruption.220 * @c: UBIFS file-system description object221 * @lnum: LEB number of corruption222 * @offs: offset of corruption223 * @buf: buffer containing corruption224 */225void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,226 void *buf)227{228 int len;229 230 ubifs_err(c, "corruption at LEB %d:%d", lnum, offs);231 len = c->leb_size - offs;232 if (len > 8192)233 len = 8192;234 ubifs_err(c, "first %d bytes from LEB %d:%d", len, lnum, offs);235 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);236}237 238/**239 * ubifs_scan - scan a logical eraseblock.240 * @c: UBIFS file-system description object241 * @lnum: logical eraseblock number242 * @offs: offset to start at (usually zero)243 * @sbuf: scan buffer (must be of @c->leb_size bytes in size)244 * @quiet: print no messages245 *246 * This function scans LEB number @lnum and returns complete information about247 * its contents. Returns the scanned information in case of success and,248 * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case249 * of failure.250 *251 * If @quiet is non-zero, this function does not print large and scary252 * error messages and flash dumps in case of errors.253 */254struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,255 int offs, void *sbuf, int quiet)256{257 void *buf = sbuf + offs;258 int err, len = c->leb_size - offs;259 struct ubifs_scan_leb *sleb;260 261 sleb = ubifs_start_scan(c, lnum, offs, sbuf);262 if (IS_ERR(sleb))263 return sleb;264 265 while (len >= 8) {266 struct ubifs_ch *ch = buf;267 int node_len, ret;268 269 dbg_scan("look at LEB %d:%d (%d bytes left)",270 lnum, offs, len);271 272 cond_resched();273 274 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);275 if (ret > 0) {276 /* Padding bytes or a valid padding node */277 offs += ret;278 buf += ret;279 len -= ret;280 continue;281 }282 283 if (ret == SCANNED_EMPTY_SPACE)284 /* Empty space is checked later */285 break;286 287 switch (ret) {288 case SCANNED_GARBAGE:289 ubifs_err(c, "garbage");290 goto corrupted;291 case SCANNED_A_NODE:292 break;293 case SCANNED_A_CORRUPT_NODE:294 case SCANNED_A_BAD_PAD_NODE:295 ubifs_err(c, "bad node");296 goto corrupted;297 default:298 ubifs_err(c, "unknown");299 err = -EINVAL;300 goto error;301 }302 303 err = ubifs_add_snod(c, sleb, buf, offs);304 if (err)305 goto error;306 307 node_len = ALIGN(le32_to_cpu(ch->len), 8);308 offs += node_len;309 buf += node_len;310 len -= node_len;311 }312 313 if (offs % c->min_io_size) {314 if (!quiet)315 ubifs_err(c, "empty space starts at non-aligned offset %d",316 offs);317 goto corrupted;318 }319 320 ubifs_end_scan(c, sleb, lnum, offs);321 322 for (; len > 4; offs += 4, buf = buf + 4, len -= 4)323 if (*(uint32_t *)buf != 0xffffffff)324 break;325 for (; len; offs++, buf++, len--)326 if (*(uint8_t *)buf != 0xff) {327 if (!quiet)328 ubifs_err(c, "corrupt empty space at LEB %d:%d",329 lnum, offs);330 goto corrupted;331 }332 333 return sleb;334 335corrupted:336 if (!quiet) {337 ubifs_scanned_corruption(c, lnum, offs, buf);338 ubifs_err(c, "LEB %d scanning failed", lnum);339 }340 err = -EUCLEAN;341 ubifs_scan_destroy(sleb);342 return ERR_PTR(err);343 344error:345 ubifs_err(c, "LEB %d scanning failed, error %d", lnum, err);346 ubifs_scan_destroy(sleb);347 return ERR_PTR(err);348}349 350/**351 * ubifs_scan_destroy - destroy LEB scanning information.352 * @sleb: scanning information to free353 */354void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)355{356 struct ubifs_scan_node *node;357 struct list_head *head;358 359 head = &sleb->nodes;360 while (!list_empty(head)) {361 node = list_entry(head->next, struct ubifs_scan_node, list);362 list_del(&node->list);363 kfree(node);364 }365 kfree(sleb);366}367