Linux Audio

Check our new training course

Loading...
v3.5.6
  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 */
 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
 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				ubifs_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				ubifs_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 */
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 = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);
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 = kmalloc(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		/*
216		 * The key is in the same place in all keyed
217		 * nodes.
218		 */
219		key_read(c, &ino->key, &snod->key);
220		break;
221	default:
222		invalid_key_init(c, &snod->key);
223		break;
224	}
225	list_add_tail(&snod->list, &sleb->nodes);
226	sleb->nodes_cnt += 1;
227	return 0;
228}
229
230/**
231 * ubifs_scanned_corruption - print information after UBIFS scanned corruption.
232 * @c: UBIFS file-system description object
233 * @lnum: LEB number of corruption
234 * @offs: offset of corruption
235 * @buf: buffer containing corruption
236 */
237void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
238			      void *buf)
239{
240	int len;
241
242	ubifs_err("corruption at LEB %d:%d", lnum, offs);
243	if (dbg_is_tst_rcvry(c))
244		return;
245	len = c->leb_size - offs;
246	if (len > 8192)
247		len = 8192;
248	ubifs_err("first %d bytes from LEB %d:%d", len, lnum, offs);
249	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
250}
251
252/**
253 * ubifs_scan - scan a logical eraseblock.
254 * @c: UBIFS file-system description object
255 * @lnum: logical eraseblock number
256 * @offs: offset to start at (usually zero)
257 * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
258 * @quiet: print no messages
259 *
260 * This function scans LEB number @lnum and returns complete information about
261 * its contents. Returns the scaned information in case of success and,
262 * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
263 * of failure.
264 *
265 * If @quiet is non-zero, this function does not print large and scary
266 * error messages and flash dumps in case of errors.
267 */
268struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
269				  int offs, void *sbuf, int quiet)
270{
271	void *buf = sbuf + offs;
272	int err, len = c->leb_size - offs;
273	struct ubifs_scan_leb *sleb;
274
275	sleb = ubifs_start_scan(c, lnum, offs, sbuf);
276	if (IS_ERR(sleb))
277		return sleb;
278
279	while (len >= 8) {
280		struct ubifs_ch *ch = buf;
281		int node_len, ret;
282
283		dbg_scan("look at LEB %d:%d (%d bytes left)",
284			 lnum, offs, len);
285
286		cond_resched();
287
288		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
289		if (ret > 0) {
290			/* Padding bytes or a valid padding node */
291			offs += ret;
292			buf += ret;
293			len -= ret;
294			continue;
295		}
296
297		if (ret == SCANNED_EMPTY_SPACE)
298			/* Empty space is checked later */
299			break;
300
301		switch (ret) {
302		case SCANNED_GARBAGE:
303			ubifs_err("garbage");
304			goto corrupted;
305		case SCANNED_A_NODE:
306			break;
307		case SCANNED_A_CORRUPT_NODE:
308		case SCANNED_A_BAD_PAD_NODE:
309			ubifs_err("bad node");
310			goto corrupted;
311		default:
312			ubifs_err("unknown");
313			err = -EINVAL;
314			goto error;
315		}
316
317		err = ubifs_add_snod(c, sleb, buf, offs);
318		if (err)
319			goto error;
320
321		node_len = ALIGN(le32_to_cpu(ch->len), 8);
322		offs += node_len;
323		buf += node_len;
324		len -= node_len;
325	}
326
327	if (offs % c->min_io_size) {
328		if (!quiet)
329			ubifs_err("empty space starts at non-aligned offset %d",
330				  offs);
331		goto corrupted;
332	}
333
334	ubifs_end_scan(c, sleb, lnum, offs);
335
336	for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
337		if (*(uint32_t *)buf != 0xffffffff)
338			break;
339	for (; len; offs++, buf++, len--)
340		if (*(uint8_t *)buf != 0xff) {
341			if (!quiet)
342				ubifs_err("corrupt empty space at LEB %d:%d",
343					  lnum, offs);
344			goto corrupted;
345		}
346
347	return sleb;
348
349corrupted:
350	if (!quiet) {
351		ubifs_scanned_corruption(c, lnum, offs, buf);
352		ubifs_err("LEB %d scanning failed", lnum);
353	}
354	err = -EUCLEAN;
355	ubifs_scan_destroy(sleb);
356	return ERR_PTR(err);
357
358error:
359	ubifs_err("LEB %d scanning failed, error %d", lnum, err);
360	ubifs_scan_destroy(sleb);
361	return ERR_PTR(err);
362}
363
364/**
365 * ubifs_scan_destroy - destroy LEB scanning information.
366 * @sleb: scanning information to free
367 */
368void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
369{
370	struct ubifs_scan_node *node;
371	struct list_head *head;
372
373	head = &sleb->nodes;
374	while (!list_empty(head)) {
375		node = list_entry(head->next, struct ubifs_scan_node, list);
376		list_del(&node->list);
377		kfree(node);
378	}
379	kfree(sleb);
380}
v3.1
  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 */
 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
 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 */
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 = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);
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 = kmalloc(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		/*
216		 * The key is in the same place in all keyed
217		 * nodes.
218		 */
219		key_read(c, &ino->key, &snod->key);
220		break;
221	default:
222		invalid_key_init(c, &snod->key);
223		break;
224	}
225	list_add_tail(&snod->list, &sleb->nodes);
226	sleb->nodes_cnt += 1;
227	return 0;
228}
229
230/**
231 * ubifs_scanned_corruption - print information after UBIFS scanned corruption.
232 * @c: UBIFS file-system description object
233 * @lnum: LEB number of corruption
234 * @offs: offset of corruption
235 * @buf: buffer containing corruption
236 */
237void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
238			      void *buf)
239{
240	int len;
241
242	ubifs_err("corruption at LEB %d:%d", lnum, offs);
243	if (dbg_is_tst_rcvry(c))
244		return;
245	len = c->leb_size - offs;
246	if (len > 8192)
247		len = 8192;
248	dbg_err("first %d bytes from LEB %d:%d", len, lnum, offs);
249	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
250}
251
252/**
253 * ubifs_scan - scan a logical eraseblock.
254 * @c: UBIFS file-system description object
255 * @lnum: logical eraseblock number
256 * @offs: offset to start at (usually zero)
257 * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
258 * @quiet: print no messages
259 *
260 * This function scans LEB number @lnum and returns complete information about
261 * its contents. Returns the scaned information in case of success and,
262 * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
263 * of failure.
264 *
265 * If @quiet is non-zero, this function does not print large and scary
266 * error messages and flash dumps in case of errors.
267 */
268struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
269				  int offs, void *sbuf, int quiet)
270{
271	void *buf = sbuf + offs;
272	int err, len = c->leb_size - offs;
273	struct ubifs_scan_leb *sleb;
274
275	sleb = ubifs_start_scan(c, lnum, offs, sbuf);
276	if (IS_ERR(sleb))
277		return sleb;
278
279	while (len >= 8) {
280		struct ubifs_ch *ch = buf;
281		int node_len, ret;
282
283		dbg_scan("look at LEB %d:%d (%d bytes left)",
284			 lnum, offs, len);
285
286		cond_resched();
287
288		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
289		if (ret > 0) {
290			/* Padding bytes or a valid padding node */
291			offs += ret;
292			buf += ret;
293			len -= ret;
294			continue;
295		}
296
297		if (ret == SCANNED_EMPTY_SPACE)
298			/* Empty space is checked later */
299			break;
300
301		switch (ret) {
302		case SCANNED_GARBAGE:
303			dbg_err("garbage");
304			goto corrupted;
305		case SCANNED_A_NODE:
306			break;
307		case SCANNED_A_CORRUPT_NODE:
308		case SCANNED_A_BAD_PAD_NODE:
309			dbg_err("bad node");
310			goto corrupted;
311		default:
312			dbg_err("unknown");
313			err = -EINVAL;
314			goto error;
315		}
316
317		err = ubifs_add_snod(c, sleb, buf, offs);
318		if (err)
319			goto error;
320
321		node_len = ALIGN(le32_to_cpu(ch->len), 8);
322		offs += node_len;
323		buf += node_len;
324		len -= node_len;
325	}
326
327	if (offs % c->min_io_size) {
328		if (!quiet)
329			ubifs_err("empty space starts at non-aligned offset %d",
330				  offs);
331		goto corrupted;
332	}
333
334	ubifs_end_scan(c, sleb, lnum, offs);
335
336	for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
337		if (*(uint32_t *)buf != 0xffffffff)
338			break;
339	for (; len; offs++, buf++, len--)
340		if (*(uint8_t *)buf != 0xff) {
341			if (!quiet)
342				ubifs_err("corrupt empty space at LEB %d:%d",
343					  lnum, offs);
344			goto corrupted;
345		}
346
347	return sleb;
348
349corrupted:
350	if (!quiet) {
351		ubifs_scanned_corruption(c, lnum, offs, buf);
352		ubifs_err("LEB %d scanning failed", lnum);
353	}
354	err = -EUCLEAN;
355	ubifs_scan_destroy(sleb);
356	return ERR_PTR(err);
357
358error:
359	ubifs_err("LEB %d scanning failed, error %d", lnum, err);
360	ubifs_scan_destroy(sleb);
361	return ERR_PTR(err);
362}
363
364/**
365 * ubifs_scan_destroy - destroy LEB scanning information.
366 * @sleb: scanning information to free
367 */
368void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
369{
370	struct ubifs_scan_node *node;
371	struct list_head *head;
372
373	head = &sleb->nodes;
374	while (!list_empty(head)) {
375		node = list_entry(head->next, struct ubifs_scan_node, list);
376		list_del(&node->list);
377		kfree(node);
378	}
379	kfree(sleb);
380}