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Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
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 */
40static 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 */
69int 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
Adrian Hunter2953e732008-09-04 16:26:00 +030090 if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
Artem Bityutskiy1e517642008-07-14 19:08:37 +030091 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) {
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300111 if (!quiet)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300112 dbg_err("bad padding length %d - %d",
113 offs, offs + node_len + pad_len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300114 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 */
135struct 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 */
174void 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 */
193int 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 */
235void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
236 void *buf)
237{
238 int len;
239
Artem Bityutskiy086b3642009-06-29 16:25:33 +0300240 ubifs_err("corruption at LEB %d:%d", lnum, offs);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300241 if (dbg_failure_mode)
242 return;
243 len = c->leb_size - offs;
Artem Bityutskiy086b3642009-06-29 16:25:33 +0300244 if (len > 8192)
245 len = 8192;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300246 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)
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300255 * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
256 * @quiet: print no messages
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300257 *
258 * This function scans LEB number @lnum and returns complete information about
Artem Bityutskiyed43f2f2009-06-29 17:59:23 +0300259 * 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.
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300262 *
263 * If @quiet is non-zero, this function does not print large and scary
264 * error messages and flash dumps in case of errors.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300265 */
266struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300267 int offs, void *sbuf, int quiet)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300268{
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
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300286 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300287 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");
Artem Bityutskiyed43f2f2009-06-29 17:59:23 +0300311 err = -EINVAL;
312 goto error;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300313 }
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
Artem Bityutskiyed43f2f2009-06-29 17:59:23 +0300325 if (offs % c->min_io_size) {
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300326 if (!quiet)
327 ubifs_err("empty space starts at non-aligned offset %d",
328 offs);
Artem Bityutskiyed43f2f2009-06-29 17:59:23 +0300329 goto corrupted;;
330 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300331
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) {
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300339 if (!quiet)
340 ubifs_err("corrupt empty space at LEB %d:%d",
341 lnum, offs);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300342 goto corrupted;
343 }
344
345 return sleb;
346
347corrupted:
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300348 if (!quiet) {
349 ubifs_scanned_corruption(c, lnum, offs, buf);
350 ubifs_err("LEB %d scanning failed", lnum);
351 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300352 err = -EUCLEAN;
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300353 ubifs_scan_destroy(sleb);
354 return ERR_PTR(err);
355
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300356error:
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300357 ubifs_err("LEB %d scanning failed, error %d", lnum, err);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300358 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 */
366void 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}