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TOMOYO Linux Cross Reference
Linux/fs/ubifs/sb.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 /*
 24  * This file implements UBIFS superblock. The superblock is stored at the first
 25  * LEB of the volume and is never changed by UBIFS. Only user-space tools may
 26  * change it. The superblock node mostly contains geometry information.
 27  */
 28 
 29 #include "ubifs.h"
 30 #include <linux/slab.h>
 31 #include <linux/math64.h>
 32 #include <linux/uuid.h>
 33 
 34 /*
 35  * Default journal size in logical eraseblocks as a percent of total
 36  * flash size.
 37  */
 38 #define DEFAULT_JNL_PERCENT 5
 39 
 40 /* Default maximum journal size in bytes */
 41 #define DEFAULT_MAX_JNL (32*1024*1024)
 42 
 43 /* Default indexing tree fanout */
 44 #define DEFAULT_FANOUT 8
 45 
 46 /* Default number of data journal heads */
 47 #define DEFAULT_JHEADS_CNT 1
 48 
 49 /* Default positions of different LEBs in the main area */
 50 #define DEFAULT_IDX_LEB  0
 51 #define DEFAULT_DATA_LEB 1
 52 #define DEFAULT_GC_LEB   2
 53 
 54 /* Default number of LEB numbers in LPT's save table */
 55 #define DEFAULT_LSAVE_CNT 256
 56 
 57 /* Default reserved pool size as a percent of maximum free space */
 58 #define DEFAULT_RP_PERCENT 5
 59 
 60 /* The default maximum size of reserved pool in bytes */
 61 #define DEFAULT_MAX_RP_SIZE (5*1024*1024)
 62 
 63 /* Default time granularity in nanoseconds */
 64 #define DEFAULT_TIME_GRAN 1000000000
 65 
 66 /**
 67  * create_default_filesystem - format empty UBI volume.
 68  * @c: UBIFS file-system description object
 69  *
 70  * This function creates default empty file-system. Returns zero in case of
 71  * success and a negative error code in case of failure.
 72  */
 73 static int create_default_filesystem(struct ubifs_info *c)
 74 {
 75         struct ubifs_sb_node *sup;
 76         struct ubifs_mst_node *mst;
 77         struct ubifs_idx_node *idx;
 78         struct ubifs_branch *br;
 79         struct ubifs_ino_node *ino;
 80         struct ubifs_cs_node *cs;
 81         union ubifs_key key;
 82         int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
 83         int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
 84         int min_leb_cnt = UBIFS_MIN_LEB_CNT;
 85         long long tmp64, main_bytes;
 86         __le64 tmp_le64;
 87 
 88         /* Some functions called from here depend on the @c->key_len filed */
 89         c->key_len = UBIFS_SK_LEN;
 90 
 91         /*
 92          * First of all, we have to calculate default file-system geometry -
 93          * log size, journal size, etc.
 94          */
 95         if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
 96                 /* We can first multiply then divide and have no overflow */
 97                 jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
 98         else
 99                 jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
100 
101         if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
102                 jnl_lebs = UBIFS_MIN_JNL_LEBS;
103         if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
104                 jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
105 
106         /*
107          * The log should be large enough to fit reference nodes for all bud
108          * LEBs. Because buds do not have to start from the beginning of LEBs
109          * (half of the LEB may contain committed data), the log should
110          * generally be larger, make it twice as large.
111          */
112         tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
113         log_lebs = tmp / c->leb_size;
114         /* Plus one LEB reserved for commit */
115         log_lebs += 1;
116         if (c->leb_cnt - min_leb_cnt > 8) {
117                 /* And some extra space to allow writes while committing */
118                 log_lebs += 1;
119                 min_leb_cnt += 1;
120         }
121 
122         max_buds = jnl_lebs - log_lebs;
123         if (max_buds < UBIFS_MIN_BUD_LEBS)
124                 max_buds = UBIFS_MIN_BUD_LEBS;
125 
126         /*
127          * Orphan nodes are stored in a separate area. One node can store a lot
128          * of orphan inode numbers, but when new orphan comes we just add a new
129          * orphan node. At some point the nodes are consolidated into one
130          * orphan node.
131          */
132         orph_lebs = UBIFS_MIN_ORPH_LEBS;
133         if (c->leb_cnt - min_leb_cnt > 1)
134                 /*
135                  * For debugging purposes it is better to have at least 2
136                  * orphan LEBs, because the orphan subsystem would need to do
137                  * consolidations and would be stressed more.
138                  */
139                 orph_lebs += 1;
140 
141         main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
142         main_lebs -= orph_lebs;
143 
144         lpt_first = UBIFS_LOG_LNUM + log_lebs;
145         c->lsave_cnt = DEFAULT_LSAVE_CNT;
146         c->max_leb_cnt = c->leb_cnt;
147         err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
148                                     &big_lpt);
149         if (err)
150                 return err;
151 
152         dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
153                 lpt_first + lpt_lebs - 1);
154 
155         main_first = c->leb_cnt - main_lebs;
156 
157         /* Create default superblock */
158         tmp = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
159         sup = kzalloc(tmp, GFP_KERNEL);
160         if (!sup)
161                 return -ENOMEM;
162 
163         tmp64 = (long long)max_buds * c->leb_size;
164         if (big_lpt)
165                 sup_flags |= UBIFS_FLG_BIGLPT;
166         sup_flags |= UBIFS_FLG_DOUBLE_HASH;
167 
168         sup->ch.node_type  = UBIFS_SB_NODE;
169         sup->key_hash      = UBIFS_KEY_HASH_R5;
170         sup->flags         = cpu_to_le32(sup_flags);
171         sup->min_io_size   = cpu_to_le32(c->min_io_size);
172         sup->leb_size      = cpu_to_le32(c->leb_size);
173         sup->leb_cnt       = cpu_to_le32(c->leb_cnt);
174         sup->max_leb_cnt   = cpu_to_le32(c->max_leb_cnt);
175         sup->max_bud_bytes = cpu_to_le64(tmp64);
176         sup->log_lebs      = cpu_to_le32(log_lebs);
177         sup->lpt_lebs      = cpu_to_le32(lpt_lebs);
178         sup->orph_lebs     = cpu_to_le32(orph_lebs);
179         sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);
180         sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
181         sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
182         sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);
183         sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
184         if (c->mount_opts.override_compr)
185                 sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
186         else
187                 sup->default_compr = cpu_to_le16(UBIFS_COMPR_LZO);
188 
189         generate_random_uuid(sup->uuid);
190 
191         main_bytes = (long long)main_lebs * c->leb_size;
192         tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
193         if (tmp64 > DEFAULT_MAX_RP_SIZE)
194                 tmp64 = DEFAULT_MAX_RP_SIZE;
195         sup->rp_size = cpu_to_le64(tmp64);
196         sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
197 
198         err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0);
199         kfree(sup);
200         if (err)
201                 return err;
202 
203         dbg_gen("default superblock created at LEB 0:0");
204 
205         /* Create default master node */
206         mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
207         if (!mst)
208                 return -ENOMEM;
209 
210         mst->ch.node_type = UBIFS_MST_NODE;
211         mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
212         mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
213         mst->cmt_no       = 0;
214         mst->root_lnum    = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
215         mst->root_offs    = 0;
216         tmp = ubifs_idx_node_sz(c, 1);
217         mst->root_len     = cpu_to_le32(tmp);
218         mst->gc_lnum      = cpu_to_le32(main_first + DEFAULT_GC_LEB);
219         mst->ihead_lnum   = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
220         mst->ihead_offs   = cpu_to_le32(ALIGN(tmp, c->min_io_size));
221         mst->index_size   = cpu_to_le64(ALIGN(tmp, 8));
222         mst->lpt_lnum     = cpu_to_le32(c->lpt_lnum);
223         mst->lpt_offs     = cpu_to_le32(c->lpt_offs);
224         mst->nhead_lnum   = cpu_to_le32(c->nhead_lnum);
225         mst->nhead_offs   = cpu_to_le32(c->nhead_offs);
226         mst->ltab_lnum    = cpu_to_le32(c->ltab_lnum);
227         mst->ltab_offs    = cpu_to_le32(c->ltab_offs);
228         mst->lsave_lnum   = cpu_to_le32(c->lsave_lnum);
229         mst->lsave_offs   = cpu_to_le32(c->lsave_offs);
230         mst->lscan_lnum   = cpu_to_le32(main_first);
231         mst->empty_lebs   = cpu_to_le32(main_lebs - 2);
232         mst->idx_lebs     = cpu_to_le32(1);
233         mst->leb_cnt      = cpu_to_le32(c->leb_cnt);
234 
235         /* Calculate lprops statistics */
236         tmp64 = main_bytes;
237         tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
238         tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
239         mst->total_free = cpu_to_le64(tmp64);
240 
241         tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
242         ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
243                           UBIFS_INO_NODE_SZ;
244         tmp64 += ino_waste;
245         tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
246         mst->total_dirty = cpu_to_le64(tmp64);
247 
248         /*  The indexing LEB does not contribute to dark space */
249         tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
250         mst->total_dark = cpu_to_le64(tmp64);
251 
252         mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
253 
254         err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0);
255         if (err) {
256                 kfree(mst);
257                 return err;
258         }
259         err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
260                                0);
261         kfree(mst);
262         if (err)
263                 return err;
264 
265         dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
266 
267         /* Create the root indexing node */
268         tmp = ubifs_idx_node_sz(c, 1);
269         idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
270         if (!idx)
271                 return -ENOMEM;
272 
273         c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
274         c->key_hash = key_r5_hash;
275 
276         idx->ch.node_type = UBIFS_IDX_NODE;
277         idx->child_cnt = cpu_to_le16(1);
278         ino_key_init(c, &key, UBIFS_ROOT_INO);
279         br = ubifs_idx_branch(c, idx, 0);
280         key_write_idx(c, &key, &br->key);
281         br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
282         br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);
283         err = ubifs_write_node(c, idx, tmp, main_first + DEFAULT_IDX_LEB, 0);
284         kfree(idx);
285         if (err)
286                 return err;
287 
288         dbg_gen("default root indexing node created LEB %d:0",
289                 main_first + DEFAULT_IDX_LEB);
290 
291         /* Create default root inode */
292         tmp = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
293         ino = kzalloc(tmp, GFP_KERNEL);
294         if (!ino)
295                 return -ENOMEM;
296 
297         ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
298         ino->ch.node_type = UBIFS_INO_NODE;
299         ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
300         ino->nlink = cpu_to_le32(2);
301         tmp_le64 = cpu_to_le64(CURRENT_TIME_SEC.tv_sec);
302         ino->atime_sec   = tmp_le64;
303         ino->ctime_sec   = tmp_le64;
304         ino->mtime_sec   = tmp_le64;
305         ino->atime_nsec  = 0;
306         ino->ctime_nsec  = 0;
307         ino->mtime_nsec  = 0;
308         ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
309         ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
310 
311         /* Set compression enabled by default */
312         ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
313 
314         err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
315                                main_first + DEFAULT_DATA_LEB, 0);
316         kfree(ino);
317         if (err)
318                 return err;
319 
320         dbg_gen("root inode created at LEB %d:0",
321                 main_first + DEFAULT_DATA_LEB);
322 
323         /*
324          * The first node in the log has to be the commit start node. This is
325          * always the case during normal file-system operation. Write a fake
326          * commit start node to the log.
327          */
328         tmp = ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size);
329         cs = kzalloc(tmp, GFP_KERNEL);
330         if (!cs)
331                 return -ENOMEM;
332 
333         cs->ch.node_type = UBIFS_CS_NODE;
334         err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
335         kfree(cs);
336         if (err)
337                 return err;
338 
339         ubifs_msg(c, "default file-system created");
340         return 0;
341 }
342 
343 /**
344  * validate_sb - validate superblock node.
345  * @c: UBIFS file-system description object
346  * @sup: superblock node
347  *
348  * This function validates superblock node @sup. Since most of data was read
349  * from the superblock and stored in @c, the function validates fields in @c
350  * instead. Returns zero in case of success and %-EINVAL in case of validation
351  * failure.
352  */
353 static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
354 {
355         long long max_bytes;
356         int err = 1, min_leb_cnt;
357 
358         if (!c->key_hash) {
359                 err = 2;
360                 goto failed;
361         }
362 
363         if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
364                 err = 3;
365                 goto failed;
366         }
367 
368         if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
369                 ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
370                           le32_to_cpu(sup->min_io_size), c->min_io_size);
371                 goto failed;
372         }
373 
374         if (le32_to_cpu(sup->leb_size) != c->leb_size) {
375                 ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
376                           le32_to_cpu(sup->leb_size), c->leb_size);
377                 goto failed;
378         }
379 
380         if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
381             c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
382             c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
383             c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
384                 err = 4;
385                 goto failed;
386         }
387 
388         /*
389          * Calculate minimum allowed amount of main area LEBs. This is very
390          * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
391          * have just read from the superblock.
392          */
393         min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
394         min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
395 
396         if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
397                 ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
398                           c->leb_cnt, c->vi.size, min_leb_cnt);
399                 goto failed;
400         }
401 
402         if (c->max_leb_cnt < c->leb_cnt) {
403                 ubifs_err(c, "max. LEB count %d less than LEB count %d",
404                           c->max_leb_cnt, c->leb_cnt);
405                 goto failed;
406         }
407 
408         if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
409                 ubifs_err(c, "too few main LEBs count %d, must be at least %d",
410                           c->main_lebs, UBIFS_MIN_MAIN_LEBS);
411                 goto failed;
412         }
413 
414         max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
415         if (c->max_bud_bytes < max_bytes) {
416                 ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
417                           c->max_bud_bytes, max_bytes);
418                 goto failed;
419         }
420 
421         max_bytes = (long long)c->leb_size * c->main_lebs;
422         if (c->max_bud_bytes > max_bytes) {
423                 ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
424                           c->max_bud_bytes, max_bytes);
425                 goto failed;
426         }
427 
428         if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
429             c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
430                 err = 9;
431                 goto failed;
432         }
433 
434         if (c->fanout < UBIFS_MIN_FANOUT ||
435             ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
436                 err = 10;
437                 goto failed;
438         }
439 
440         if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
441             c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
442             c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
443                 err = 11;
444                 goto failed;
445         }
446 
447         if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
448             c->orph_lebs + c->main_lebs != c->leb_cnt) {
449                 err = 12;
450                 goto failed;
451         }
452 
453         if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
454                 err = 13;
455                 goto failed;
456         }
457 
458         if (c->rp_size < 0 || max_bytes < c->rp_size) {
459                 err = 14;
460                 goto failed;
461         }
462 
463         if (le32_to_cpu(sup->time_gran) > 1000000000 ||
464             le32_to_cpu(sup->time_gran) < 1) {
465                 err = 15;
466                 goto failed;
467         }
468 
469         if (!c->double_hash && c->fmt_version >= 5) {
470                 err = 16;
471                 goto failed;
472         }
473 
474         if (c->encrypted && c->fmt_version < 5) {
475                 err = 17;
476                 goto failed;
477         }
478 
479         return 0;
480 
481 failed:
482         ubifs_err(c, "bad superblock, error %d", err);
483         ubifs_dump_node(c, sup);
484         return -EINVAL;
485 }
486 
487 /**
488  * ubifs_read_sb_node - read superblock node.
489  * @c: UBIFS file-system description object
490  *
491  * This function returns a pointer to the superblock node or a negative error
492  * code. Note, the user of this function is responsible of kfree()'ing the
493  * returned superblock buffer.
494  */
495 struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
496 {
497         struct ubifs_sb_node *sup;
498         int err;
499 
500         sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
501         if (!sup)
502                 return ERR_PTR(-ENOMEM);
503 
504         err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
505                               UBIFS_SB_LNUM, 0);
506         if (err) {
507                 kfree(sup);
508                 return ERR_PTR(err);
509         }
510 
511         return sup;
512 }
513 
514 /**
515  * ubifs_write_sb_node - write superblock node.
516  * @c: UBIFS file-system description object
517  * @sup: superblock node read with 'ubifs_read_sb_node()'
518  *
519  * This function returns %0 on success and a negative error code on failure.
520  */
521 int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
522 {
523         int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
524 
525         ubifs_prepare_node(c, sup, UBIFS_SB_NODE_SZ, 1);
526         return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
527 }
528 
529 /**
530  * ubifs_read_superblock - read superblock.
531  * @c: UBIFS file-system description object
532  *
533  * This function finds, reads and checks the superblock. If an empty UBI volume
534  * is being mounted, this function creates default superblock. Returns zero in
535  * case of success, and a negative error code in case of failure.
536  */
537 int ubifs_read_superblock(struct ubifs_info *c)
538 {
539         int err, sup_flags;
540         struct ubifs_sb_node *sup;
541 
542         if (c->empty) {
543                 err = create_default_filesystem(c);
544                 if (err)
545                         return err;
546         }
547 
548         sup = ubifs_read_sb_node(c);
549         if (IS_ERR(sup))
550                 return PTR_ERR(sup);
551 
552         c->fmt_version = le32_to_cpu(sup->fmt_version);
553         c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
554 
555         /*
556          * The software supports all previous versions but not future versions,
557          * due to the unavailability of time-travelling equipment.
558          */
559         if (c->fmt_version > UBIFS_FORMAT_VERSION) {
560                 ubifs_assert(!c->ro_media || c->ro_mount);
561                 if (!c->ro_mount ||
562                     c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
563                         ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
564                                   c->fmt_version, c->ro_compat_version,
565                                   UBIFS_FORMAT_VERSION,
566                                   UBIFS_RO_COMPAT_VERSION);
567                         if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
568                                 ubifs_msg(c, "only R/O mounting is possible");
569                                 err = -EROFS;
570                         } else
571                                 err = -EINVAL;
572                         goto out;
573                 }
574 
575                 /*
576                  * The FS is mounted R/O, and the media format is
577                  * R/O-compatible with the UBIFS implementation, so we can
578                  * mount.
579                  */
580                 c->rw_incompat = 1;
581         }
582 
583         if (c->fmt_version < 3) {
584                 ubifs_err(c, "on-flash format version %d is not supported",
585                           c->fmt_version);
586                 err = -EINVAL;
587                 goto out;
588         }
589 
590         switch (sup->key_hash) {
591         case UBIFS_KEY_HASH_R5:
592                 c->key_hash = key_r5_hash;
593                 c->key_hash_type = UBIFS_KEY_HASH_R5;
594                 break;
595 
596         case UBIFS_KEY_HASH_TEST:
597                 c->key_hash = key_test_hash;
598                 c->key_hash_type = UBIFS_KEY_HASH_TEST;
599                 break;
600         };
601 
602         c->key_fmt = sup->key_fmt;
603 
604         switch (c->key_fmt) {
605         case UBIFS_SIMPLE_KEY_FMT:
606                 c->key_len = UBIFS_SK_LEN;
607                 break;
608         default:
609                 ubifs_err(c, "unsupported key format");
610                 err = -EINVAL;
611                 goto out;
612         }
613 
614         c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
615         c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
616         c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
617         c->log_lebs      = le32_to_cpu(sup->log_lebs);
618         c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
619         c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
620         c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
621         c->fanout        = le32_to_cpu(sup->fanout);
622         c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
623         c->rp_size       = le64_to_cpu(sup->rp_size);
624         c->rp_uid        = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid));
625         c->rp_gid        = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid));
626         sup_flags        = le32_to_cpu(sup->flags);
627         if (!c->mount_opts.override_compr)
628                 c->default_compr = le16_to_cpu(sup->default_compr);
629 
630         c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
631         memcpy(&c->uuid, &sup->uuid, 16);
632         c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
633         c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
634         c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
635         c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
636 
637         if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
638                 ubifs_err(c, "Unknown feature flags found: %#x",
639                           sup_flags & ~UBIFS_FLG_MASK);
640                 err = -EINVAL;
641                 goto out;
642         }
643 
644 #ifndef CONFIG_UBIFS_FS_ENCRYPTION
645         if (c->encrypted) {
646                 ubifs_err(c, "file system contains encrypted files but UBIFS"
647                              " was built without crypto support.");
648                 err = -EINVAL;
649                 goto out;
650         }
651 #endif
652 
653         /* Automatically increase file system size to the maximum size */
654         c->old_leb_cnt = c->leb_cnt;
655         if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
656                 c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
657                 if (c->ro_mount)
658                         dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
659                                 c->old_leb_cnt, c->leb_cnt);
660                 else {
661                         dbg_mnt("Auto resizing (sb) from %d LEBs to %d LEBs",
662                                 c->old_leb_cnt, c->leb_cnt);
663                         sup->leb_cnt = cpu_to_le32(c->leb_cnt);
664                         err = ubifs_write_sb_node(c, sup);
665                         if (err)
666                                 goto out;
667                         c->old_leb_cnt = c->leb_cnt;
668                 }
669         }
670 
671         c->log_bytes = (long long)c->log_lebs * c->leb_size;
672         c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
673         c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
674         c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
675         c->orph_first = c->lpt_last + 1;
676         c->orph_last = c->orph_first + c->orph_lebs - 1;
677         c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
678         c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
679         c->main_first = c->leb_cnt - c->main_lebs;
680 
681         err = validate_sb(c, sup);
682 out:
683         kfree(sup);
684         return err;
685 }
686 
687 /**
688  * fixup_leb - fixup/unmap an LEB containing free space.
689  * @c: UBIFS file-system description object
690  * @lnum: the LEB number to fix up
691  * @len: number of used bytes in LEB (starting at offset 0)
692  *
693  * This function reads the contents of the given LEB number @lnum, then fixes
694  * it up, so that empty min. I/O units in the end of LEB are actually erased on
695  * flash (rather than being just all-0xff real data). If the LEB is completely
696  * empty, it is simply unmapped.
697  */
698 static int fixup_leb(struct ubifs_info *c, int lnum, int len)
699 {
700         int err;
701 
702         ubifs_assert(len >= 0);
703         ubifs_assert(len % c->min_io_size == 0);
704         ubifs_assert(len < c->leb_size);
705 
706         if (len == 0) {
707                 dbg_mnt("unmap empty LEB %d", lnum);
708                 return ubifs_leb_unmap(c, lnum);
709         }
710 
711         dbg_mnt("fixup LEB %d, data len %d", lnum, len);
712         err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
713         if (err)
714                 return err;
715 
716         return ubifs_leb_change(c, lnum, c->sbuf, len);
717 }
718 
719 /**
720  * fixup_free_space - find & remap all LEBs containing free space.
721  * @c: UBIFS file-system description object
722  *
723  * This function walks through all LEBs in the filesystem and fiexes up those
724  * containing free/empty space.
725  */
726 static int fixup_free_space(struct ubifs_info *c)
727 {
728         int lnum, err = 0;
729         struct ubifs_lprops *lprops;
730 
731         ubifs_get_lprops(c);
732 
733         /* Fixup LEBs in the master area */
734         for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
735                 err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
736                 if (err)
737                         goto out;
738         }
739 
740         /* Unmap unused log LEBs */
741         lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
742         while (lnum != c->ltail_lnum) {
743                 err = fixup_leb(c, lnum, 0);
744                 if (err)
745                         goto out;
746                 lnum = ubifs_next_log_lnum(c, lnum);
747         }
748 
749         /*
750          * Fixup the log head which contains the only a CS node at the
751          * beginning.
752          */
753         err = fixup_leb(c, c->lhead_lnum,
754                         ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
755         if (err)
756                 goto out;
757 
758         /* Fixup LEBs in the LPT area */
759         for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
760                 int free = c->ltab[lnum - c->lpt_first].free;
761 
762                 if (free > 0) {
763                         err = fixup_leb(c, lnum, c->leb_size - free);
764                         if (err)
765                                 goto out;
766                 }
767         }
768 
769         /* Unmap LEBs in the orphans area */
770         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
771                 err = fixup_leb(c, lnum, 0);
772                 if (err)
773                         goto out;
774         }
775 
776         /* Fixup LEBs in the main area */
777         for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
778                 lprops = ubifs_lpt_lookup(c, lnum);
779                 if (IS_ERR(lprops)) {
780                         err = PTR_ERR(lprops);
781                         goto out;
782                 }
783 
784                 if (lprops->free > 0) {
785                         err = fixup_leb(c, lnum, c->leb_size - lprops->free);
786                         if (err)
787                                 goto out;
788                 }
789         }
790 
791 out:
792         ubifs_release_lprops(c);
793         return err;
794 }
795 
796 /**
797  * ubifs_fixup_free_space - find & fix all LEBs with free space.
798  * @c: UBIFS file-system description object
799  *
800  * This function fixes up LEBs containing free space on first mount, if the
801  * appropriate flag was set when the FS was created. Each LEB with one or more
802  * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
803  * the free space is actually erased. E.g., this is necessary for some NAND
804  * chips, since the free space may have been programmed like real "0xff" data
805  * (generating a non-0xff ECC), causing future writes to the not-really-erased
806  * NAND pages to behave badly. After the space is fixed up, the superblock flag
807  * is cleared, so that this is skipped for all future mounts.
808  */
809 int ubifs_fixup_free_space(struct ubifs_info *c)
810 {
811         int err;
812         struct ubifs_sb_node *sup;
813 
814         ubifs_assert(c->space_fixup);
815         ubifs_assert(!c->ro_mount);
816 
817         ubifs_msg(c, "start fixing up free space");
818 
819         err = fixup_free_space(c);
820         if (err)
821                 return err;
822 
823         sup = ubifs_read_sb_node(c);
824         if (IS_ERR(sup))
825                 return PTR_ERR(sup);
826 
827         /* Free-space fixup is no longer required */
828         c->space_fixup = 0;
829         sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
830 
831         err = ubifs_write_sb_node(c, sup);
832         kfree(sup);
833         if (err)
834                 return err;
835 
836         ubifs_msg(c, "free space fixup complete");
837         return err;
838 }
839 
840 int ubifs_enable_encryption(struct ubifs_info *c)
841 {
842         int err;
843         struct ubifs_sb_node *sup;
844 
845         if (c->encrypted)
846                 return 0;
847 
848         if (c->ro_mount || c->ro_media)
849                 return -EROFS;
850 
851         if (c->fmt_version < 5) {
852                 ubifs_err(c, "on-flash format version 5 is needed for encryption");
853                 return -EINVAL;
854         }
855 
856         sup = ubifs_read_sb_node(c);
857         if (IS_ERR(sup))
858                 return PTR_ERR(sup);
859 
860         sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);
861 
862         err = ubifs_write_sb_node(c, sup);
863         if (!err)
864                 c->encrypted = 1;
865         kfree(sup);
866 
867         return err;
868 }
869 

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