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: Artem Bityutskiy (Битюцкий Артём)
20 *          Adrian Hunter
21 */
22
23/* This file implements reading and writing the master node */
24
25#include "ubifs.h"
26
27/**
28 * scan_for_master - search the valid master node.
29 * @c: UBIFS file-system description object
30 *
31 * This function scans the master node LEBs and search for the latest master
32 * node. Returns zero in case of success, %-EUCLEAN if there master area is
33 * corrupted and requires recovery, and a negative error code in case of
34 * failure.
35 */
36static int scan_for_master(struct ubifs_info *c)
37{
38	struct ubifs_scan_leb *sleb;
39	struct ubifs_scan_node *snod;
40	int lnum, offs = 0, nodes_cnt;
41
42	lnum = UBIFS_MST_LNUM;
43
44	sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
45	if (IS_ERR(sleb))
46		return PTR_ERR(sleb);
47	nodes_cnt = sleb->nodes_cnt;
48	if (nodes_cnt > 0) {
49		snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
50				  list);
51		if (snod->type != UBIFS_MST_NODE)
52			goto out_dump;
53		memcpy(c->mst_node, snod->node, snod->len);
54		offs = snod->offs;
55	}
56	ubifs_scan_destroy(sleb);
57
58	lnum += 1;
59
60	sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
61	if (IS_ERR(sleb))
62		return PTR_ERR(sleb);
63	if (sleb->nodes_cnt != nodes_cnt)
64		goto out;
65	if (!sleb->nodes_cnt)
66		goto out;
67	snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
68	if (snod->type != UBIFS_MST_NODE)
69		goto out_dump;
70	if (snod->offs != offs)
71		goto out;
72	if (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
73		   (void *)snod->node + UBIFS_CH_SZ,
74		   UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
75		goto out;
76	c->mst_offs = offs;
77	ubifs_scan_destroy(sleb);
78	return 0;
79
80out:
81	ubifs_scan_destroy(sleb);
82	return -EUCLEAN;
83
84out_dump:
85	ubifs_err(c, "unexpected node type %d master LEB %d:%d",
86		  snod->type, lnum, snod->offs);
87	ubifs_scan_destroy(sleb);
88	return -EINVAL;
89}
90
91/**
92 * validate_master - validate master node.
93 * @c: UBIFS file-system description object
94 *
95 * This function validates data which was read from master node. Returns zero
96 * if the data is all right and %-EINVAL if not.
97 */
98static int validate_master(const struct ubifs_info *c)
99{
100	long long main_sz;
101	int err;
102
103	if (c->max_sqnum >= SQNUM_WATERMARK) {
104		err = 1;
105		goto out;
106	}
107
108	if (c->cmt_no >= c->max_sqnum) {
109		err = 2;
110		goto out;
111	}
112
113	if (c->highest_inum >= INUM_WATERMARK) {
114		err = 3;
115		goto out;
116	}
117
118	if (c->lhead_lnum < UBIFS_LOG_LNUM ||
119	    c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
120	    c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
121	    c->lhead_offs & (c->min_io_size - 1)) {
122		err = 4;
123		goto out;
124	}
125
126	if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
127	    c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
128		err = 5;
129		goto out;
130	}
131
132	if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
133	    c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
134		err = 6;
135		goto out;
136	}
137
138	if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
139		err = 7;
140		goto out;
141	}
142
143	if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
144	    c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
145	    c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
146		err = 8;
147		goto out;
148	}
149
150	main_sz = (long long)c->main_lebs * c->leb_size;
151	if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
152		err = 9;
153		goto out;
154	}
155
156	if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
157	    c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
158		err = 10;
159		goto out;
160	}
161
162	if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
163	    c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
164	    c->nhead_offs > c->leb_size) {
165		err = 11;
166		goto out;
167	}
168
169	if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
170	    c->ltab_offs < 0 ||
171	    c->ltab_offs + c->ltab_sz > c->leb_size) {
172		err = 12;
173		goto out;
174	}
175
176	if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
177	    c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
178	    c->lsave_offs + c->lsave_sz > c->leb_size)) {
179		err = 13;
180		goto out;
181	}
182
183	if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
184		err = 14;
185		goto out;
186	}
187
188	if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
189		err = 15;
190		goto out;
191	}
192
193	if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
194		err = 16;
195		goto out;
196	}
197
198	if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
199	    c->lst.total_free & 7) {
200		err = 17;
201		goto out;
202	}
203
204	if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
205		err = 18;
206		goto out;
207	}
208
209	if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
210		err = 19;
211		goto out;
212	}
213
214	if (c->lst.total_free + c->lst.total_dirty +
215	    c->lst.total_used > main_sz) {
216		err = 20;
217		goto out;
218	}
219
220	if (c->lst.total_dead + c->lst.total_dark +
221	    c->lst.total_used + c->bi.old_idx_sz > main_sz) {
222		err = 21;
223		goto out;
224	}
225
226	if (c->lst.total_dead < 0 ||
227	    c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
228	    c->lst.total_dead & 7) {
229		err = 22;
230		goto out;
231	}
232
233	if (c->lst.total_dark < 0 ||
234	    c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
235	    c->lst.total_dark & 7) {
236		err = 23;
237		goto out;
238	}
239
240	return 0;
241
242out:
243	ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
244	ubifs_dump_node(c, c->mst_node);
245	return -EINVAL;
246}
247
248/**
249 * ubifs_read_master - read master node.
250 * @c: UBIFS file-system description object
251 *
252 * This function finds and reads the master node during file-system mount. If
253 * the flash is empty, it creates default master node as well. Returns zero in
254 * case of success and a negative error code in case of failure.
255 */
256int ubifs_read_master(struct ubifs_info *c)
257{
258	int err, old_leb_cnt;
259
260	c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
261	if (!c->mst_node)
262		return -ENOMEM;
263
264	err = scan_for_master(c);
265	if (err) {
266		if (err == -EUCLEAN)
267			err = ubifs_recover_master_node(c);
268		if (err)
269			/*
270			 * Note, we do not free 'c->mst_node' here because the
271			 * unmount routine will take care of this.
272			 */
273			return err;
274	}
275
276	/* Make sure that the recovery flag is clear */
277	c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
278
279	c->max_sqnum       = le64_to_cpu(c->mst_node->ch.sqnum);
280	c->highest_inum    = le64_to_cpu(c->mst_node->highest_inum);
281	c->cmt_no          = le64_to_cpu(c->mst_node->cmt_no);
282	c->zroot.lnum      = le32_to_cpu(c->mst_node->root_lnum);
283	c->zroot.offs      = le32_to_cpu(c->mst_node->root_offs);
284	c->zroot.len       = le32_to_cpu(c->mst_node->root_len);
285	c->lhead_lnum      = le32_to_cpu(c->mst_node->log_lnum);
286	c->gc_lnum         = le32_to_cpu(c->mst_node->gc_lnum);
287	c->ihead_lnum      = le32_to_cpu(c->mst_node->ihead_lnum);
288	c->ihead_offs      = le32_to_cpu(c->mst_node->ihead_offs);
289	c->bi.old_idx_sz   = le64_to_cpu(c->mst_node->index_size);
290	c->lpt_lnum        = le32_to_cpu(c->mst_node->lpt_lnum);
291	c->lpt_offs        = le32_to_cpu(c->mst_node->lpt_offs);
292	c->nhead_lnum      = le32_to_cpu(c->mst_node->nhead_lnum);
293	c->nhead_offs      = le32_to_cpu(c->mst_node->nhead_offs);
294	c->ltab_lnum       = le32_to_cpu(c->mst_node->ltab_lnum);
295	c->ltab_offs       = le32_to_cpu(c->mst_node->ltab_offs);
296	c->lsave_lnum      = le32_to_cpu(c->mst_node->lsave_lnum);
297	c->lsave_offs      = le32_to_cpu(c->mst_node->lsave_offs);
298	c->lscan_lnum      = le32_to_cpu(c->mst_node->lscan_lnum);
299	c->lst.empty_lebs  = le32_to_cpu(c->mst_node->empty_lebs);
300	c->lst.idx_lebs    = le32_to_cpu(c->mst_node->idx_lebs);
301	old_leb_cnt        = le32_to_cpu(c->mst_node->leb_cnt);
302	c->lst.total_free  = le64_to_cpu(c->mst_node->total_free);
303	c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
304	c->lst.total_used  = le64_to_cpu(c->mst_node->total_used);
305	c->lst.total_dead  = le64_to_cpu(c->mst_node->total_dead);
306	c->lst.total_dark  = le64_to_cpu(c->mst_node->total_dark);
307
308	c->calc_idx_sz = c->bi.old_idx_sz;
309
310	if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
311		c->no_orphs = 1;
312
313	if (old_leb_cnt != c->leb_cnt) {
314		/* The file system has been resized */
315		int growth = c->leb_cnt - old_leb_cnt;
316
317		if (c->leb_cnt < old_leb_cnt ||
318		    c->leb_cnt < UBIFS_MIN_LEB_CNT) {
319			ubifs_err(c, "bad leb_cnt on master node");
320			ubifs_dump_node(c, c->mst_node);
321			return -EINVAL;
322		}
323
324		dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
325			old_leb_cnt, c->leb_cnt);
326		c->lst.empty_lebs += growth;
327		c->lst.total_free += growth * (long long)c->leb_size;
328		c->lst.total_dark += growth * (long long)c->dark_wm;
329
330		/*
331		 * Reflect changes back onto the master node. N.B. the master
332		 * node gets written immediately whenever mounting (or
333		 * remounting) in read-write mode, so we do not need to write it
334		 * here.
335		 */
336		c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
337		c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
338		c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
339		c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
340	}
341
342	err = validate_master(c);
343	if (err)
344		return err;
345
346	err = dbg_old_index_check_init(c, &c->zroot);
347
348	return err;
349}
350
351/**
352 * ubifs_write_master - write master node.
353 * @c: UBIFS file-system description object
354 *
355 * This function writes the master node. Returns zero in case of success and a
356 * negative error code in case of failure. The master node is written twice to
357 * enable recovery.
358 */
359int ubifs_write_master(struct ubifs_info *c)
360{
361	int err, lnum, offs, len;
362
363	ubifs_assert(!c->ro_media && !c->ro_mount);
364	if (c->ro_error)
365		return -EROFS;
366
367	lnum = UBIFS_MST_LNUM;
368	offs = c->mst_offs + c->mst_node_alsz;
369	len = UBIFS_MST_NODE_SZ;
370
371	if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
372		err = ubifs_leb_unmap(c, lnum);
373		if (err)
374			return err;
375		offs = 0;
376	}
377
378	c->mst_offs = offs;
379	c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
380
381	err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
382	if (err)
383		return err;
384
385	lnum += 1;
386
387	if (offs == 0) {
388		err = ubifs_leb_unmap(c, lnum);
389		if (err)
390			return err;
391	}
392	err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
393
394	return err;
395}
396