[net-next-2.6.git] / fs / ubifs / scan.c

/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Authors: Adrian Hunter
 *          Artem Bityutskiy (Битюцкий Артём)
 */

/*
 * This file implements the scan which is a general-purpose function for
 * determining what nodes are in an eraseblock. The scan is used to replay the
 * journal, to do garbage collection. for the TNC in-the-gaps method, and by
 * debugging functions.
 */

#include "ubifs.h"

/**
 * scan_padding_bytes - scan for padding bytes.
 * @buf: buffer to scan
 * @len: length of buffer
 *
 * This function returns the number of padding bytes on success and
 * %SCANNED_GARBAGE on failure.
 */
static int scan_padding_bytes(void *buf, int len)
{
	int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);
	uint8_t *p = buf;

	dbg_scan("not a node");

	while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)
		pad_len += 1;

	if (!pad_len || (pad_len & 7))
		return SCANNED_GARBAGE;

	dbg_scan("%d padding bytes", pad_len);

	return pad_len;
}

/**
 * ubifs_scan_a_node - scan for a node or padding.
 * @c: UBIFS file-system description object
 * @buf: buffer to scan
 * @len: length of buffer
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 * @quiet: print no messages
 *
 * This function returns a scanning code to indicate what was scanned.
 */
int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
		      int offs, int quiet)
{
	struct ubifs_ch *ch = buf;
	uint32_t magic;

	magic = le32_to_cpu(ch->magic);

	if (magic == 0xFFFFFFFF) {
		dbg_scan("hit empty space");
		return SCANNED_EMPTY_SPACE;
	}

	if (magic != UBIFS_NODE_MAGIC)
		return scan_padding_bytes(buf, len);

	if (len < UBIFS_CH_SZ)
		return SCANNED_GARBAGE;

	dbg_scan("scanning %s", dbg_ntype(ch->node_type));

	if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
		return SCANNED_A_CORRUPT_NODE;

	if (ch->node_type == UBIFS_PAD_NODE) {
		struct ubifs_pad_node *pad = buf;
		int pad_len = le32_to_cpu(pad->pad_len);
		int node_len = le32_to_cpu(ch->len);

		/* Validate the padding node */
		if (pad_len < 0 ||
		    offs + node_len + pad_len > c->leb_size) {
			if (!quiet) {
				ubifs_err("bad pad node at LEB %d:%d",
					  lnum, offs);
				dbg_dump_node(c, pad);
			}
			return SCANNED_A_BAD_PAD_NODE;
		}

		/* Make the node pads to 8-byte boundary */
		if ((node_len + pad_len) & 7) {
			if (!quiet) {
				dbg_err("bad padding length %d - %d",
					offs, offs + node_len + pad_len);
			}
			return SCANNED_A_BAD_PAD_NODE;
		}

		dbg_scan("%d bytes padded, offset now %d",
			 pad_len, ALIGN(offs + node_len + pad_len, 8));

		return node_len + pad_len;
	}

	return SCANNED_A_NODE;
}

/**
 * ubifs_start_scan - create LEB scanning information at start of scan.
 * @c: UBIFS file-system description object
 * @lnum: logical eraseblock number
 * @offs: offset to start at (usually zero)
 * @sbuf: scan buffer (must be c->leb_size)
 *
 * This function returns %0 on success and a negative error code on failure.
 */
struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
					int offs, void *sbuf)
{
	struct ubifs_scan_leb *sleb;
	int err;

	dbg_scan("scan LEB %d:%d", lnum, offs);

	sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
	if (!sleb)
		return ERR_PTR(-ENOMEM);

	sleb->lnum = lnum;
	INIT_LIST_HEAD(&sleb->nodes);
	sleb->buf = sbuf;

	err = ubi_read(c->ubi, lnum, sbuf + offs, offs, c->leb_size - offs);
	if (err && err != -EBADMSG) {
		ubifs_err("cannot read %d bytes from LEB %d:%d,"
			  " error %d", c->leb_size - offs, lnum, offs, err);
		kfree(sleb);
		return ERR_PTR(err);
	}

	if (err == -EBADMSG)
		sleb->ecc = 1;

	return sleb;
}

/**
 * ubifs_end_scan - update LEB scanning information at end of scan.
 * @c: UBIFS file-system description object
 * @sleb: scanning information
 * @lnum: logical eraseblock number
 * @offs: offset to start at (usually zero)
 *
 * This function returns %0 on success and a negative error code on failure.
 */
void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
		    int lnum, int offs)
{
	lnum = lnum;
	dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
	ubifs_assert(offs % c->min_io_size == 0);

	sleb->endpt = ALIGN(offs, c->min_io_size);
}

/**
 * ubifs_add_snod - add a scanned node to LEB scanning information.
 * @c: UBIFS file-system description object
 * @sleb: scanning information
 * @buf: buffer containing node
 * @offs: offset of node on flash
 *
 * This function returns %0 on success and a negative error code on failure.
 */
int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
		   void *buf, int offs)
{
	struct ubifs_ch *ch = buf;
	struct ubifs_ino_node *ino = buf;
	struct ubifs_scan_node *snod;

	snod = kzalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
	if (!snod)
		return -ENOMEM;

	snod->sqnum = le64_to_cpu(ch->sqnum);
	snod->type = ch->node_type;
	snod->offs = offs;
	snod->len = le32_to_cpu(ch->len);
	snod->node = buf;

	switch (ch->node_type) {
	case UBIFS_INO_NODE:
	case UBIFS_DENT_NODE:
	case UBIFS_XENT_NODE:
	case UBIFS_DATA_NODE:
	case UBIFS_TRUN_NODE:
		/*
		 * The key is in the same place in all keyed
		 * nodes.
		 */
		key_read(c, &ino->key, &snod->key);
		break;
	}
	list_add_tail(&snod->list, &sleb->nodes);
	sleb->nodes_cnt += 1;
	return 0;
}

/**
 * ubifs_scanned_corruption - print information after UBIFS scanned corruption.
 * @c: UBIFS file-system description object
 * @lnum: LEB number of corruption
 * @offs: offset of corruption
 * @buf: buffer containing corruption
 */
void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
			      void *buf)
{
	int len;

	ubifs_err("corruption at LEB %d:%d", lnum, offs);
	if (dbg_failure_mode)
		return;
	len = c->leb_size - offs;
	if (len > 8192)
		len = 8192;
	dbg_err("first %d bytes from LEB %d:%d", len, lnum, offs);
	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
}

/**
 * ubifs_scan - scan a logical eraseblock.
 * @c: UBIFS file-system description object
 * @lnum: logical eraseblock number
 * @offs: offset to start at (usually zero)
 * @sbuf: scan buffer (must be c->leb_size)
 *
 * This function scans LEB number @lnum and returns complete information about
 * its contents. Returns an error code in case of failure.
 */
struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
				  int offs, void *sbuf)
{
	void *buf = sbuf + offs;
	int err, len = c->leb_size - offs;
	struct ubifs_scan_leb *sleb;

	sleb = ubifs_start_scan(c, lnum, offs, sbuf);
	if (IS_ERR(sleb))
		return sleb;

	while (len >= 8) {
		struct ubifs_ch *ch = buf;
		int node_len, ret;

		dbg_scan("look at LEB %d:%d (%d bytes left)",
			 lnum, offs, len);

		cond_resched();

		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 0);

		if (ret > 0) {
			/* Padding bytes or a valid padding node */
			offs += ret;
			buf += ret;
			len -= ret;
			continue;
		}

		if (ret == SCANNED_EMPTY_SPACE)
			/* Empty space is checked later */
			break;

		switch (ret) {
		case SCANNED_GARBAGE:
			dbg_err("garbage");
			goto corrupted;
		case SCANNED_A_NODE:
			break;
		case SCANNED_A_CORRUPT_NODE:
		case SCANNED_A_BAD_PAD_NODE:
			dbg_err("bad node");
			goto corrupted;
		default:
			dbg_err("unknown");
			goto corrupted;
		}

		err = ubifs_add_snod(c, sleb, buf, offs);
		if (err)
			goto error;

		node_len = ALIGN(le32_to_cpu(ch->len), 8);
		offs += node_len;
		buf += node_len;
		len -= node_len;
	}

	if (offs % c->min_io_size)
		goto corrupted;

	ubifs_end_scan(c, sleb, lnum, offs);

	for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
		if (*(uint32_t *)buf != 0xffffffff)
			break;
	for (; len; offs++, buf++, len--)
		if (*(uint8_t *)buf != 0xff) {
			ubifs_err("corrupt empty space at LEB %d:%d",
				  lnum, offs);
			goto corrupted;
		}

	return sleb;

corrupted:
	ubifs_scanned_corruption(c, lnum, offs, buf);
	err = -EUCLEAN;
error:
	ubifs_err("LEB %d scanning failed", lnum);
	ubifs_scan_destroy(sleb);
	return ERR_PTR(err);
}

/**
 * ubifs_scan_destroy - destroy LEB scanning information.
 * @sleb: scanning information to free
 */
void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
{
	struct ubifs_scan_node *node;
	struct list_head *head;

	head = &sleb->nodes;
	while (!list_empty(head)) {
		node = list_entry(head->next, struct ubifs_scan_node, list);
		list_del(&node->list);
		kfree(node);
	}
	kfree(sleb);
}
Commit	Line	Data
1e51764a AB	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
2953e73f	90	if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
1e51764a AB	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	}
	115	return SCANNED_A_BAD_PAD_NODE;
	116	}
	117
	118	dbg_scan("%d bytes padded, offset now %d",
	119	pad_len, ALIGN(offs + node_len + pad_len, 8));
	120
	121	return node_len + pad_len;
	122	}
	123
	124	return SCANNED_A_NODE;
	125	}
	126
	127	/**
	128	* ubifs_start_scan - create LEB scanning information at start of scan.
	129	* @c: UBIFS file-system description object
	130	* @lnum: logical eraseblock number
	131	* @offs: offset to start at (usually zero)
	132	* @sbuf: scan buffer (must be c->leb_size)
	133	*
	134	* This function returns %0 on success and a negative error code on failure.
	135	*/
	136	struct ubifs_scan_leb ubifs_start_scan(const struct ubifs_info c, int lnum,
	137	int offs, void *sbuf)
	138	{
	139	struct ubifs_scan_leb *sleb;
	140	int err;
	141
	142	dbg_scan("scan LEB %d:%d", lnum, offs);
	143
	144	sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
	145	if (!sleb)
	146	return ERR_PTR(-ENOMEM);
	147
	148	sleb->lnum = lnum;
	149	INIT_LIST_HEAD(&sleb->nodes);
	150	sleb->buf = sbuf;
	151
	152	err = ubi_read(c->ubi, lnum, sbuf + offs, offs, c->leb_size - offs);
	153	if (err && err != -EBADMSG) {
	154	ubifs_err("cannot read %d bytes from LEB %d:%d,"
155	" error %d", c->leb_size - offs, lnum, offs, err);
156	kfree(sleb);
157	return ERR_PTR(err);
158	}
159
160	if (err == -EBADMSG)
161	sleb->ecc = 1;
162
163	return sleb;
164	}
165
166	/**
167	* ubifs_end_scan - update LEB scanning information at end of scan.
168	* @c: UBIFS file-system description object
169	* @sleb: scanning information
170	* @lnum: logical eraseblock number
171	* @offs: offset to start at (usually zero)
172	*
173	* This function returns %0 on success and a negative error code on failure.
174	*/
175	void ubifs_end_scan(const struct ubifs_info c, struct ubifs_scan_leb sleb,
176	int lnum, int offs)
177	{
178	lnum = lnum;
179	dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
180	ubifs_assert(offs % c->min_io_size == 0);
181
182	sleb->endpt = ALIGN(offs, c->min_io_size);
183	}
184
185	/**
186	* ubifs_add_snod - add a scanned node to LEB scanning information.
187	* @c: UBIFS file-system description object
188	* @sleb: scanning information
189	* @buf: buffer containing node
190	* @offs: offset of node on flash
191	*
192	* This function returns %0 on success and a negative error code on failure.
193	*/
194	int ubifs_add_snod(const struct ubifs_info c, struct ubifs_scan_leb sleb,
195	void *buf, int offs)
196	{
197	struct ubifs_ch *ch = buf;
198	struct ubifs_ino_node *ino = buf;
199	struct ubifs_scan_node *snod;
200
201	snod = kzalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
202	if (!snod)
203	return -ENOMEM;
204
205	snod->sqnum = le64_to_cpu(ch->sqnum);
206	snod->type = ch->node_type;
207	snod->offs = offs;
208	snod->len = le32_to_cpu(ch->len);
209	snod->node = buf;
210
211	switch (ch->node_type) {
212	case UBIFS_INO_NODE:
213	case UBIFS_DENT_NODE:
214	case UBIFS_XENT_NODE:
215	case UBIFS_DATA_NODE:
216	case UBIFS_TRUN_NODE:
217	/*
218	* The key is in the same place in all keyed
219	* nodes.
220	*/
221	key_read(c, &ino->key, &snod->key);
222	break;
223	}
224	list_add_tail(&snod->list, &sleb->nodes);
225	sleb->nodes_cnt += 1;
226	return 0;
227	}
228
229	/**
230	* ubifs_scanned_corruption - print information after UBIFS scanned corruption.
231	* @c: UBIFS file-system description object
232	* @lnum: LEB number of corruption
233	* @offs: offset of corruption
234	* @buf: buffer containing corruption
235	*/
236	void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
237	void *buf)
238	{
239	int len;
240
086b3640	241	ubifs_err("corruption at LEB %d:%d", lnum, offs);
1e51764a AB	242	if (dbg_failure_mode)
	243	return;
	244	len = c->leb_size - offs;
086b3640 AB	245	if (len > 8192)
086b3640 AB	246	len = 8192;
1e51764a AB	247	dbg_err("first %d bytes from LEB %d:%d", len, lnum, offs);
	248	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
	249	}
	250
	251	/**
	252	* ubifs_scan - scan a logical eraseblock.
	253	* @c: UBIFS file-system description object
	254	* @lnum: logical eraseblock number
	255	* @offs: offset to start at (usually zero)
	256	* @sbuf: scan buffer (must be c->leb_size)
	257	*
	258	* This function scans LEB number @lnum and returns complete information about
	259	* its contents. Returns an error code in case of failure.
	260	*/
	261	struct ubifs_scan_leb ubifs_scan(const struct ubifs_info c, int lnum,
	262	int offs, void *sbuf)
	263	{
	264	void *buf = sbuf + offs;
	265	int err, len = c->leb_size - offs;
	266	struct ubifs_scan_leb *sleb;
	267
	268	sleb = ubifs_start_scan(c, lnum, offs, sbuf);
	269	if (IS_ERR(sleb))
	270	return sleb;
	271
	272	while (len >= 8) {
	273	struct ubifs_ch *ch = buf;
	274	int node_len, ret;
	275
	276	dbg_scan("look at LEB %d:%d (%d bytes left)",
	277	lnum, offs, len);
	278
	279	cond_resched();
	280
	281	ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 0);
	282
	283	if (ret > 0) {
	284	/* Padding bytes or a valid padding node */
	285	offs += ret;
	286	buf += ret;
	287	len -= ret;
	288	continue;
	289	}
	290
	291	if (ret == SCANNED_EMPTY_SPACE)
	292	/* Empty space is checked later */
	293	break;
	294
	295	switch (ret) {
	296	case SCANNED_GARBAGE:
	297	dbg_err("garbage");
	298	goto corrupted;
	299	case SCANNED_A_NODE:
	300	break;
	301	case SCANNED_A_CORRUPT_NODE:
	302	case SCANNED_A_BAD_PAD_NODE:
	303	dbg_err("bad node");
	304	goto corrupted;
	305	default:
	306	dbg_err("unknown");
	307	goto corrupted;
	308	}
	309
	310	err = ubifs_add_snod(c, sleb, buf, offs);
311	if (err)
312	goto error;
313
314	node_len = ALIGN(le32_to_cpu(ch->len), 8);
315	offs += node_len;
316	buf += node_len;
317	len -= node_len;
318	}
319
320	if (offs % c->min_io_size)
321	goto corrupted;
322
323	ubifs_end_scan(c, sleb, lnum, offs);
324
325	for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
326	if ((uint32_t )buf != 0xffffffff)
327	break;
328	for (; len; offs++, buf++, len--)
329	if ((uint8_t )buf != 0xff) {
330	ubifs_err("corrupt empty space at LEB %d:%d",
331	lnum, offs);
332	goto corrupted;
333	}
334
335	return sleb;
336
337	corrupted:
338	ubifs_scanned_corruption(c, lnum, offs, buf);
339	err = -EUCLEAN;
340	error:
341	ubifs_err("LEB %d scanning failed", lnum);
342	ubifs_scan_destroy(sleb);
343	return ERR_PTR(err);
344	}
345
346	/**
347	* ubifs_scan_destroy - destroy LEB scanning information.
348	* @sleb: scanning information to free
349	*/
350	void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
351	{
352	struct ubifs_scan_node *node;
353	struct list_head *head;
354
355	head = &sleb->nodes;
356	while (!list_empty(head)) {
357	node = list_entry(head->next, struct ubifs_scan_node, list);
358	list_del(&node->list);
359	kfree(node);
360	}
361	kfree(sleb);
362	}