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Linux/fs/ubifs/master.c

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  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  */
 36 static 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 
 80 out:
 81         ubifs_scan_destroy(sleb);
 82         return -EUCLEAN;
 83 
 84 out_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  */
 98 static 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 
242 out:
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  */
256 int 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  */
359 int 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 

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