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TOMOYO Linux Cross Reference
Linux/fs/ubifs/super.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 initialization and VFS superblock operations. Some
 25  * initialization stuff which is rather large and complex is placed at
 26  * corresponding subsystems, but most of it is here.
 27  */
 28 
 29 #include <linux/init.h>
 30 #include <linux/slab.h>
 31 #include <linux/module.h>
 32 #include <linux/ctype.h>
 33 #include <linux/kthread.h>
 34 #include <linux/parser.h>
 35 #include <linux/seq_file.h>
 36 #include <linux/mount.h>
 37 #include <linux/math64.h>
 38 #include <linux/writeback.h>
 39 #include "ubifs.h"
 40 
 41 /*
 42  * Maximum amount of memory we may 'kmalloc()' without worrying that we are
 43  * allocating too much.
 44  */
 45 #define UBIFS_KMALLOC_OK (128*1024)
 46 
 47 /* Slab cache for UBIFS inodes */
 48 static struct kmem_cache *ubifs_inode_slab;
 49 
 50 /* UBIFS TNC shrinker description */
 51 static struct shrinker ubifs_shrinker_info = {
 52         .scan_objects = ubifs_shrink_scan,
 53         .count_objects = ubifs_shrink_count,
 54         .seeks = DEFAULT_SEEKS,
 55 };
 56 
 57 /**
 58  * validate_inode - validate inode.
 59  * @c: UBIFS file-system description object
 60  * @inode: the inode to validate
 61  *
 62  * This is a helper function for 'ubifs_iget()' which validates various fields
 63  * of a newly built inode to make sure they contain sane values and prevent
 64  * possible vulnerabilities. Returns zero if the inode is all right and
 65  * a non-zero error code if not.
 66  */
 67 static int validate_inode(struct ubifs_info *c, const struct inode *inode)
 68 {
 69         int err;
 70         const struct ubifs_inode *ui = ubifs_inode(inode);
 71 
 72         if (inode->i_size > c->max_inode_sz) {
 73                 ubifs_err(c, "inode is too large (%lld)",
 74                           (long long)inode->i_size);
 75                 return 1;
 76         }
 77 
 78         if (ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
 79                 ubifs_err(c, "unknown compression type %d", ui->compr_type);
 80                 return 2;
 81         }
 82 
 83         if (ui->xattr_names + ui->xattr_cnt > XATTR_LIST_MAX)
 84                 return 3;
 85 
 86         if (ui->data_len < 0 || ui->data_len > UBIFS_MAX_INO_DATA)
 87                 return 4;
 88 
 89         if (ui->xattr && !S_ISREG(inode->i_mode))
 90                 return 5;
 91 
 92         if (!ubifs_compr_present(ui->compr_type)) {
 93                 ubifs_warn(c, "inode %lu uses '%s' compression, but it was not compiled in",
 94                            inode->i_ino, ubifs_compr_name(ui->compr_type));
 95         }
 96 
 97         err = dbg_check_dir(c, inode);
 98         return err;
 99 }
100 
101 struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
102 {
103         int err;
104         union ubifs_key key;
105         struct ubifs_ino_node *ino;
106         struct ubifs_info *c = sb->s_fs_info;
107         struct inode *inode;
108         struct ubifs_inode *ui;
109 
110         dbg_gen("inode %lu", inum);
111 
112         inode = iget_locked(sb, inum);
113         if (!inode)
114                 return ERR_PTR(-ENOMEM);
115         if (!(inode->i_state & I_NEW))
116                 return inode;
117         ui = ubifs_inode(inode);
118 
119         ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
120         if (!ino) {
121                 err = -ENOMEM;
122                 goto out;
123         }
124 
125         ino_key_init(c, &key, inode->i_ino);
126 
127         err = ubifs_tnc_lookup(c, &key, ino);
128         if (err)
129                 goto out_ino;
130 
131         inode->i_flags |= S_NOCMTIME;
132 #ifndef CONFIG_UBIFS_ATIME_SUPPORT
133         inode->i_flags |= S_NOATIME;
134 #endif
135         set_nlink(inode, le32_to_cpu(ino->nlink));
136         i_uid_write(inode, le32_to_cpu(ino->uid));
137         i_gid_write(inode, le32_to_cpu(ino->gid));
138         inode->i_atime.tv_sec  = (int64_t)le64_to_cpu(ino->atime_sec);
139         inode->i_atime.tv_nsec = le32_to_cpu(ino->atime_nsec);
140         inode->i_mtime.tv_sec  = (int64_t)le64_to_cpu(ino->mtime_sec);
141         inode->i_mtime.tv_nsec = le32_to_cpu(ino->mtime_nsec);
142         inode->i_ctime.tv_sec  = (int64_t)le64_to_cpu(ino->ctime_sec);
143         inode->i_ctime.tv_nsec = le32_to_cpu(ino->ctime_nsec);
144         inode->i_mode = le32_to_cpu(ino->mode);
145         inode->i_size = le64_to_cpu(ino->size);
146 
147         ui->data_len    = le32_to_cpu(ino->data_len);
148         ui->flags       = le32_to_cpu(ino->flags);
149         ui->compr_type  = le16_to_cpu(ino->compr_type);
150         ui->creat_sqnum = le64_to_cpu(ino->creat_sqnum);
151         ui->xattr_cnt   = le32_to_cpu(ino->xattr_cnt);
152         ui->xattr_size  = le32_to_cpu(ino->xattr_size);
153         ui->xattr_names = le32_to_cpu(ino->xattr_names);
154         ui->synced_i_size = ui->ui_size = inode->i_size;
155 
156         ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;
157 
158         err = validate_inode(c, inode);
159         if (err)
160                 goto out_invalid;
161 
162         switch (inode->i_mode & S_IFMT) {
163         case S_IFREG:
164                 inode->i_mapping->a_ops = &ubifs_file_address_operations;
165                 inode->i_op = &ubifs_file_inode_operations;
166                 inode->i_fop = &ubifs_file_operations;
167                 if (ui->xattr) {
168                         ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
169                         if (!ui->data) {
170                                 err = -ENOMEM;
171                                 goto out_ino;
172                         }
173                         memcpy(ui->data, ino->data, ui->data_len);
174                         ((char *)ui->data)[ui->data_len] = '\0';
175                 } else if (ui->data_len != 0) {
176                         err = 10;
177                         goto out_invalid;
178                 }
179                 break;
180         case S_IFDIR:
181                 inode->i_op  = &ubifs_dir_inode_operations;
182                 inode->i_fop = &ubifs_dir_operations;
183                 if (ui->data_len != 0) {
184                         err = 11;
185                         goto out_invalid;
186                 }
187                 break;
188         case S_IFLNK:
189                 inode->i_op = &ubifs_symlink_inode_operations;
190                 if (ui->data_len <= 0 || ui->data_len > UBIFS_MAX_INO_DATA) {
191                         err = 12;
192                         goto out_invalid;
193                 }
194                 ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
195                 if (!ui->data) {
196                         err = -ENOMEM;
197                         goto out_ino;
198                 }
199                 memcpy(ui->data, ino->data, ui->data_len);
200                 ((char *)ui->data)[ui->data_len] = '\0';
201                 break;
202         case S_IFBLK:
203         case S_IFCHR:
204         {
205                 dev_t rdev;
206                 union ubifs_dev_desc *dev;
207 
208                 ui->data = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
209                 if (!ui->data) {
210                         err = -ENOMEM;
211                         goto out_ino;
212                 }
213 
214                 dev = (union ubifs_dev_desc *)ino->data;
215                 if (ui->data_len == sizeof(dev->new))
216                         rdev = new_decode_dev(le32_to_cpu(dev->new));
217                 else if (ui->data_len == sizeof(dev->huge))
218                         rdev = huge_decode_dev(le64_to_cpu(dev->huge));
219                 else {
220                         err = 13;
221                         goto out_invalid;
222                 }
223                 memcpy(ui->data, ino->data, ui->data_len);
224                 inode->i_op = &ubifs_file_inode_operations;
225                 init_special_inode(inode, inode->i_mode, rdev);
226                 break;
227         }
228         case S_IFSOCK:
229         case S_IFIFO:
230                 inode->i_op = &ubifs_file_inode_operations;
231                 init_special_inode(inode, inode->i_mode, 0);
232                 if (ui->data_len != 0) {
233                         err = 14;
234                         goto out_invalid;
235                 }
236                 break;
237         default:
238                 err = 15;
239                 goto out_invalid;
240         }
241 
242         kfree(ino);
243         ubifs_set_inode_flags(inode);
244         unlock_new_inode(inode);
245         return inode;
246 
247 out_invalid:
248         ubifs_err(c, "inode %lu validation failed, error %d", inode->i_ino, err);
249         ubifs_dump_node(c, ino);
250         ubifs_dump_inode(c, inode);
251         err = -EINVAL;
252 out_ino:
253         kfree(ino);
254 out:
255         ubifs_err(c, "failed to read inode %lu, error %d", inode->i_ino, err);
256         iget_failed(inode);
257         return ERR_PTR(err);
258 }
259 
260 static struct inode *ubifs_alloc_inode(struct super_block *sb)
261 {
262         struct ubifs_inode *ui;
263 
264         ui = kmem_cache_alloc(ubifs_inode_slab, GFP_NOFS);
265         if (!ui)
266                 return NULL;
267 
268         memset((void *)ui + sizeof(struct inode), 0,
269                sizeof(struct ubifs_inode) - sizeof(struct inode));
270         mutex_init(&ui->ui_mutex);
271         spin_lock_init(&ui->ui_lock);
272         return &ui->vfs_inode;
273 };
274 
275 static void ubifs_i_callback(struct rcu_head *head)
276 {
277         struct inode *inode = container_of(head, struct inode, i_rcu);
278         struct ubifs_inode *ui = ubifs_inode(inode);
279         kmem_cache_free(ubifs_inode_slab, ui);
280 }
281 
282 static void ubifs_destroy_inode(struct inode *inode)
283 {
284         struct ubifs_inode *ui = ubifs_inode(inode);
285 
286         kfree(ui->data);
287         call_rcu(&inode->i_rcu, ubifs_i_callback);
288 }
289 
290 /*
291  * Note, Linux write-back code calls this without 'i_mutex'.
292  */
293 static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
294 {
295         int err = 0;
296         struct ubifs_info *c = inode->i_sb->s_fs_info;
297         struct ubifs_inode *ui = ubifs_inode(inode);
298 
299         ubifs_assert(!ui->xattr);
300         if (is_bad_inode(inode))
301                 return 0;
302 
303         mutex_lock(&ui->ui_mutex);
304         /*
305          * Due to races between write-back forced by budgeting
306          * (see 'sync_some_inodes()') and background write-back, the inode may
307          * have already been synchronized, do not do this again. This might
308          * also happen if it was synchronized in an VFS operation, e.g.
309          * 'ubifs_link()'.
310          */
311         if (!ui->dirty) {
312                 mutex_unlock(&ui->ui_mutex);
313                 return 0;
314         }
315 
316         /*
317          * As an optimization, do not write orphan inodes to the media just
318          * because this is not needed.
319          */
320         dbg_gen("inode %lu, mode %#x, nlink %u",
321                 inode->i_ino, (int)inode->i_mode, inode->i_nlink);
322         if (inode->i_nlink) {
323                 err = ubifs_jnl_write_inode(c, inode);
324                 if (err)
325                         ubifs_err(c, "can't write inode %lu, error %d",
326                                   inode->i_ino, err);
327                 else
328                         err = dbg_check_inode_size(c, inode, ui->ui_size);
329         }
330 
331         ui->dirty = 0;
332         mutex_unlock(&ui->ui_mutex);
333         ubifs_release_dirty_inode_budget(c, ui);
334         return err;
335 }
336 
337 static void ubifs_evict_inode(struct inode *inode)
338 {
339         int err;
340         struct ubifs_info *c = inode->i_sb->s_fs_info;
341         struct ubifs_inode *ui = ubifs_inode(inode);
342 
343         if (ui->xattr)
344                 /*
345                  * Extended attribute inode deletions are fully handled in
346                  * 'ubifs_removexattr()'. These inodes are special and have
347                  * limited usage, so there is nothing to do here.
348                  */
349                 goto out;
350 
351         dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
352         ubifs_assert(!atomic_read(&inode->i_count));
353 
354         truncate_inode_pages_final(&inode->i_data);
355 
356         if (inode->i_nlink)
357                 goto done;
358 
359         if (is_bad_inode(inode))
360                 goto out;
361 
362         ui->ui_size = inode->i_size = 0;
363         err = ubifs_jnl_delete_inode(c, inode);
364         if (err)
365                 /*
366                  * Worst case we have a lost orphan inode wasting space, so a
367                  * simple error message is OK here.
368                  */
369                 ubifs_err(c, "can't delete inode %lu, error %d",
370                           inode->i_ino, err);
371 
372 out:
373         if (ui->dirty)
374                 ubifs_release_dirty_inode_budget(c, ui);
375         else {
376                 /* We've deleted something - clean the "no space" flags */
377                 c->bi.nospace = c->bi.nospace_rp = 0;
378                 smp_wmb();
379         }
380 done:
381         clear_inode(inode);
382 #ifdef CONFIG_UBIFS_FS_ENCRYPTION
383         fscrypt_put_encryption_info(inode, NULL);
384 #endif
385 }
386 
387 static void ubifs_dirty_inode(struct inode *inode, int flags)
388 {
389         struct ubifs_inode *ui = ubifs_inode(inode);
390 
391         ubifs_assert(mutex_is_locked(&ui->ui_mutex));
392         if (!ui->dirty) {
393                 ui->dirty = 1;
394                 dbg_gen("inode %lu",  inode->i_ino);
395         }
396 }
397 
398 static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
399 {
400         struct ubifs_info *c = dentry->d_sb->s_fs_info;
401         unsigned long long free;
402         __le32 *uuid = (__le32 *)c->uuid;
403 
404         free = ubifs_get_free_space(c);
405         dbg_gen("free space %lld bytes (%lld blocks)",
406                 free, free >> UBIFS_BLOCK_SHIFT);
407 
408         buf->f_type = UBIFS_SUPER_MAGIC;
409         buf->f_bsize = UBIFS_BLOCK_SIZE;
410         buf->f_blocks = c->block_cnt;
411         buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
412         if (free > c->report_rp_size)
413                 buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
414         else
415                 buf->f_bavail = 0;
416         buf->f_files = 0;
417         buf->f_ffree = 0;
418         buf->f_namelen = UBIFS_MAX_NLEN;
419         buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
420         buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
421         ubifs_assert(buf->f_bfree <= c->block_cnt);
422         return 0;
423 }
424 
425 static int ubifs_show_options(struct seq_file *s, struct dentry *root)
426 {
427         struct ubifs_info *c = root->d_sb->s_fs_info;
428 
429         if (c->mount_opts.unmount_mode == 2)
430                 seq_puts(s, ",fast_unmount");
431         else if (c->mount_opts.unmount_mode == 1)
432                 seq_puts(s, ",norm_unmount");
433 
434         if (c->mount_opts.bulk_read == 2)
435                 seq_puts(s, ",bulk_read");
436         else if (c->mount_opts.bulk_read == 1)
437                 seq_puts(s, ",no_bulk_read");
438 
439         if (c->mount_opts.chk_data_crc == 2)
440                 seq_puts(s, ",chk_data_crc");
441         else if (c->mount_opts.chk_data_crc == 1)
442                 seq_puts(s, ",no_chk_data_crc");
443 
444         if (c->mount_opts.override_compr) {
445                 seq_printf(s, ",compr=%s",
446                            ubifs_compr_name(c->mount_opts.compr_type));
447         }
448 
449         seq_printf(s, ",ubi=%d,vol=%d", c->vi.ubi_num, c->vi.vol_id);
450 
451         return 0;
452 }
453 
454 static int ubifs_sync_fs(struct super_block *sb, int wait)
455 {
456         int i, err;
457         struct ubifs_info *c = sb->s_fs_info;
458 
459         /*
460          * Zero @wait is just an advisory thing to help the file system shove
461          * lots of data into the queues, and there will be the second
462          * '->sync_fs()' call, with non-zero @wait.
463          */
464         if (!wait)
465                 return 0;
466 
467         /*
468          * Synchronize write buffers, because 'ubifs_run_commit()' does not
469          * do this if it waits for an already running commit.
470          */
471         for (i = 0; i < c->jhead_cnt; i++) {
472                 err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
473                 if (err)
474                         return err;
475         }
476 
477         /*
478          * Strictly speaking, it is not necessary to commit the journal here,
479          * synchronizing write-buffers would be enough. But committing makes
480          * UBIFS free space predictions much more accurate, so we want to let
481          * the user be able to get more accurate results of 'statfs()' after
482          * they synchronize the file system.
483          */
484         err = ubifs_run_commit(c);
485         if (err)
486                 return err;
487 
488         return ubi_sync(c->vi.ubi_num);
489 }
490 
491 /**
492  * init_constants_early - initialize UBIFS constants.
493  * @c: UBIFS file-system description object
494  *
495  * This function initialize UBIFS constants which do not need the superblock to
496  * be read. It also checks that the UBI volume satisfies basic UBIFS
497  * requirements. Returns zero in case of success and a negative error code in
498  * case of failure.
499  */
500 static int init_constants_early(struct ubifs_info *c)
501 {
502         if (c->vi.corrupted) {
503                 ubifs_warn(c, "UBI volume is corrupted - read-only mode");
504                 c->ro_media = 1;
505         }
506 
507         if (c->di.ro_mode) {
508                 ubifs_msg(c, "read-only UBI device");
509                 c->ro_media = 1;
510         }
511 
512         if (c->vi.vol_type == UBI_STATIC_VOLUME) {
513                 ubifs_msg(c, "static UBI volume - read-only mode");
514                 c->ro_media = 1;
515         }
516 
517         c->leb_cnt = c->vi.size;
518         c->leb_size = c->vi.usable_leb_size;
519         c->leb_start = c->di.leb_start;
520         c->half_leb_size = c->leb_size / 2;
521         c->min_io_size = c->di.min_io_size;
522         c->min_io_shift = fls(c->min_io_size) - 1;
523         c->max_write_size = c->di.max_write_size;
524         c->max_write_shift = fls(c->max_write_size) - 1;
525 
526         if (c->leb_size < UBIFS_MIN_LEB_SZ) {
527                 ubifs_errc(c, "too small LEBs (%d bytes), min. is %d bytes",
528                            c->leb_size, UBIFS_MIN_LEB_SZ);
529                 return -EINVAL;
530         }
531 
532         if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
533                 ubifs_errc(c, "too few LEBs (%d), min. is %d",
534                            c->leb_cnt, UBIFS_MIN_LEB_CNT);
535                 return -EINVAL;
536         }
537 
538         if (!is_power_of_2(c->min_io_size)) {
539                 ubifs_errc(c, "bad min. I/O size %d", c->min_io_size);
540                 return -EINVAL;
541         }
542 
543         /*
544          * Maximum write size has to be greater or equivalent to min. I/O
545          * size, and be multiple of min. I/O size.
546          */
547         if (c->max_write_size < c->min_io_size ||
548             c->max_write_size % c->min_io_size ||
549             !is_power_of_2(c->max_write_size)) {
550                 ubifs_errc(c, "bad write buffer size %d for %d min. I/O unit",
551                            c->max_write_size, c->min_io_size);
552                 return -EINVAL;
553         }
554 
555         /*
556          * UBIFS aligns all node to 8-byte boundary, so to make function in
557          * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
558          * less than 8.
559          */
560         if (c->min_io_size < 8) {
561                 c->min_io_size = 8;
562                 c->min_io_shift = 3;
563                 if (c->max_write_size < c->min_io_size) {
564                         c->max_write_size = c->min_io_size;
565                         c->max_write_shift = c->min_io_shift;
566                 }
567         }
568 
569         c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
570         c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);
571 
572         /*
573          * Initialize node length ranges which are mostly needed for node
574          * length validation.
575          */
576         c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
577         c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
578         c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
579         c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
580         c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
581         c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;
582 
583         c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
584         c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
585         c->ranges[UBIFS_ORPH_NODE].min_len =
586                                 UBIFS_ORPH_NODE_SZ + sizeof(__le64);
587         c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
588         c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
589         c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
590         c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
591         c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
592         c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
593         c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
594         /*
595          * Minimum indexing node size is amended later when superblock is
596          * read and the key length is known.
597          */
598         c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
599         /*
600          * Maximum indexing node size is amended later when superblock is
601          * read and the fanout is known.
602          */
603         c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
604 
605         /*
606          * Initialize dead and dark LEB space watermarks. See gc.c for comments
607          * about these values.
608          */
609         c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
610         c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
611 
612         /*
613          * Calculate how many bytes would be wasted at the end of LEB if it was
614          * fully filled with data nodes of maximum size. This is used in
615          * calculations when reporting free space.
616          */
617         c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
618 
619         /* Buffer size for bulk-reads */
620         c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
621         if (c->max_bu_buf_len > c->leb_size)
622                 c->max_bu_buf_len = c->leb_size;
623         return 0;
624 }
625 
626 /**
627  * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
628  * @c: UBIFS file-system description object
629  * @lnum: LEB the write-buffer was synchronized to
630  * @free: how many free bytes left in this LEB
631  * @pad: how many bytes were padded
632  *
633  * This is a callback function which is called by the I/O unit when the
634  * write-buffer is synchronized. We need this to correctly maintain space
635  * accounting in bud logical eraseblocks. This function returns zero in case of
636  * success and a negative error code in case of failure.
637  *
638  * This function actually belongs to the journal, but we keep it here because
639  * we want to keep it static.
640  */
641 static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
642 {
643         return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
644 }
645 
646 /*
647  * init_constants_sb - initialize UBIFS constants.
648  * @c: UBIFS file-system description object
649  *
650  * This is a helper function which initializes various UBIFS constants after
651  * the superblock has been read. It also checks various UBIFS parameters and
652  * makes sure they are all right. Returns zero in case of success and a
653  * negative error code in case of failure.
654  */
655 static int init_constants_sb(struct ubifs_info *c)
656 {
657         int tmp, err;
658         long long tmp64;
659 
660         c->main_bytes = (long long)c->main_lebs * c->leb_size;
661         c->max_znode_sz = sizeof(struct ubifs_znode) +
662                                 c->fanout * sizeof(struct ubifs_zbranch);
663 
664         tmp = ubifs_idx_node_sz(c, 1);
665         c->ranges[UBIFS_IDX_NODE].min_len = tmp;
666         c->min_idx_node_sz = ALIGN(tmp, 8);
667 
668         tmp = ubifs_idx_node_sz(c, c->fanout);
669         c->ranges[UBIFS_IDX_NODE].max_len = tmp;
670         c->max_idx_node_sz = ALIGN(tmp, 8);
671 
672         /* Make sure LEB size is large enough to fit full commit */
673         tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
674         tmp = ALIGN(tmp, c->min_io_size);
675         if (tmp > c->leb_size) {
676                 ubifs_err(c, "too small LEB size %d, at least %d needed",
677                           c->leb_size, tmp);
678                 return -EINVAL;
679         }
680 
681         /*
682          * Make sure that the log is large enough to fit reference nodes for
683          * all buds plus one reserved LEB.
684          */
685         tmp64 = c->max_bud_bytes + c->leb_size - 1;
686         c->max_bud_cnt = div_u64(tmp64, c->leb_size);
687         tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
688         tmp /= c->leb_size;
689         tmp += 1;
690         if (c->log_lebs < tmp) {
691                 ubifs_err(c, "too small log %d LEBs, required min. %d LEBs",
692                           c->log_lebs, tmp);
693                 return -EINVAL;
694         }
695 
696         /*
697          * When budgeting we assume worst-case scenarios when the pages are not
698          * be compressed and direntries are of the maximum size.
699          *
700          * Note, data, which may be stored in inodes is budgeted separately, so
701          * it is not included into 'c->bi.inode_budget'.
702          */
703         c->bi.page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
704         c->bi.inode_budget = UBIFS_INO_NODE_SZ;
705         c->bi.dent_budget = UBIFS_MAX_DENT_NODE_SZ;
706 
707         /*
708          * When the amount of flash space used by buds becomes
709          * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
710          * The writers are unblocked when the commit is finished. To avoid
711          * writers to be blocked UBIFS initiates background commit in advance,
712          * when number of bud bytes becomes above the limit defined below.
713          */
714         c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;
715 
716         /*
717          * Ensure minimum journal size. All the bytes in the journal heads are
718          * considered to be used, when calculating the current journal usage.
719          * Consequently, if the journal is too small, UBIFS will treat it as
720          * always full.
721          */
722         tmp64 = (long long)(c->jhead_cnt + 1) * c->leb_size + 1;
723         if (c->bg_bud_bytes < tmp64)
724                 c->bg_bud_bytes = tmp64;
725         if (c->max_bud_bytes < tmp64 + c->leb_size)
726                 c->max_bud_bytes = tmp64 + c->leb_size;
727 
728         err = ubifs_calc_lpt_geom(c);
729         if (err)
730                 return err;
731 
732         /* Initialize effective LEB size used in budgeting calculations */
733         c->idx_leb_size = c->leb_size - c->max_idx_node_sz;
734         return 0;
735 }
736 
737 /*
738  * init_constants_master - initialize UBIFS constants.
739  * @c: UBIFS file-system description object
740  *
741  * This is a helper function which initializes various UBIFS constants after
742  * the master node has been read. It also checks various UBIFS parameters and
743  * makes sure they are all right.
744  */
745 static void init_constants_master(struct ubifs_info *c)
746 {
747         long long tmp64;
748 
749         c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
750         c->report_rp_size = ubifs_reported_space(c, c->rp_size);
751 
752         /*
753          * Calculate total amount of FS blocks. This number is not used
754          * internally because it does not make much sense for UBIFS, but it is
755          * necessary to report something for the 'statfs()' call.
756          *
757          * Subtract the LEB reserved for GC, the LEB which is reserved for
758          * deletions, minimum LEBs for the index, and assume only one journal
759          * head is available.
760          */
761         tmp64 = c->main_lebs - 1 - 1 - MIN_INDEX_LEBS - c->jhead_cnt + 1;
762         tmp64 *= (long long)c->leb_size - c->leb_overhead;
763         tmp64 = ubifs_reported_space(c, tmp64);
764         c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
765 }
766 
767 /**
768  * take_gc_lnum - reserve GC LEB.
769  * @c: UBIFS file-system description object
770  *
771  * This function ensures that the LEB reserved for garbage collection is marked
772  * as "taken" in lprops. We also have to set free space to LEB size and dirty
773  * space to zero, because lprops may contain out-of-date information if the
774  * file-system was un-mounted before it has been committed. This function
775  * returns zero in case of success and a negative error code in case of
776  * failure.
777  */
778 static int take_gc_lnum(struct ubifs_info *c)
779 {
780         int err;
781 
782         if (c->gc_lnum == -1) {
783                 ubifs_err(c, "no LEB for GC");
784                 return -EINVAL;
785         }
786 
787         /* And we have to tell lprops that this LEB is taken */
788         err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
789                                   LPROPS_TAKEN, 0, 0);
790         return err;
791 }
792 
793 /**
794  * alloc_wbufs - allocate write-buffers.
795  * @c: UBIFS file-system description object
796  *
797  * This helper function allocates and initializes UBIFS write-buffers. Returns
798  * zero in case of success and %-ENOMEM in case of failure.
799  */
800 static int alloc_wbufs(struct ubifs_info *c)
801 {
802         int i, err;
803 
804         c->jheads = kcalloc(c->jhead_cnt, sizeof(struct ubifs_jhead),
805                             GFP_KERNEL);
806         if (!c->jheads)
807                 return -ENOMEM;
808 
809         /* Initialize journal heads */
810         for (i = 0; i < c->jhead_cnt; i++) {
811                 INIT_LIST_HEAD(&c->jheads[i].buds_list);
812                 err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
813                 if (err)
814                         return err;
815 
816                 c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
817                 c->jheads[i].wbuf.jhead = i;
818                 c->jheads[i].grouped = 1;
819         }
820 
821         /*
822          * Garbage Collector head does not need to be synchronized by timer.
823          * Also GC head nodes are not grouped.
824          */
825         c->jheads[GCHD].wbuf.no_timer = 1;
826         c->jheads[GCHD].grouped = 0;
827 
828         return 0;
829 }
830 
831 /**
832  * free_wbufs - free write-buffers.
833  * @c: UBIFS file-system description object
834  */
835 static void free_wbufs(struct ubifs_info *c)
836 {
837         int i;
838 
839         if (c->jheads) {
840                 for (i = 0; i < c->jhead_cnt; i++) {
841                         kfree(c->jheads[i].wbuf.buf);
842                         kfree(c->jheads[i].wbuf.inodes);
843                 }
844                 kfree(c->jheads);
845                 c->jheads = NULL;
846         }
847 }
848 
849 /**
850  * free_orphans - free orphans.
851  * @c: UBIFS file-system description object
852  */
853 static void free_orphans(struct ubifs_info *c)
854 {
855         struct ubifs_orphan *orph;
856 
857         while (c->orph_dnext) {
858                 orph = c->orph_dnext;
859                 c->orph_dnext = orph->dnext;
860                 list_del(&orph->list);
861                 kfree(orph);
862         }
863 
864         while (!list_empty(&c->orph_list)) {
865                 orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
866                 list_del(&orph->list);
867                 kfree(orph);
868                 ubifs_err(c, "orphan list not empty at unmount");
869         }
870 
871         vfree(c->orph_buf);
872         c->orph_buf = NULL;
873 }
874 
875 /**
876  * free_buds - free per-bud objects.
877  * @c: UBIFS file-system description object
878  */
879 static void free_buds(struct ubifs_info *c)
880 {
881         struct ubifs_bud *bud, *n;
882 
883         rbtree_postorder_for_each_entry_safe(bud, n, &c->buds, rb)
884                 kfree(bud);
885 }
886 
887 /**
888  * check_volume_empty - check if the UBI volume is empty.
889  * @c: UBIFS file-system description object
890  *
891  * This function checks if the UBIFS volume is empty by looking if its LEBs are
892  * mapped or not. The result of checking is stored in the @c->empty variable.
893  * Returns zero in case of success and a negative error code in case of
894  * failure.
895  */
896 static int check_volume_empty(struct ubifs_info *c)
897 {
898         int lnum, err;
899 
900         c->empty = 1;
901         for (lnum = 0; lnum < c->leb_cnt; lnum++) {
902                 err = ubifs_is_mapped(c, lnum);
903                 if (unlikely(err < 0))
904                         return err;
905                 if (err == 1) {
906                         c->empty = 0;
907                         break;
908                 }
909 
910                 cond_resched();
911         }
912 
913         return 0;
914 }
915 
916 /*
917  * UBIFS mount options.
918  *
919  * Opt_fast_unmount: do not run a journal commit before un-mounting
920  * Opt_norm_unmount: run a journal commit before un-mounting
921  * Opt_bulk_read: enable bulk-reads
922  * Opt_no_bulk_read: disable bulk-reads
923  * Opt_chk_data_crc: check CRCs when reading data nodes
924  * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
925  * Opt_override_compr: override default compressor
926  * Opt_err: just end of array marker
927  */
928 enum {
929         Opt_fast_unmount,
930         Opt_norm_unmount,
931         Opt_bulk_read,
932         Opt_no_bulk_read,
933         Opt_chk_data_crc,
934         Opt_no_chk_data_crc,
935         Opt_override_compr,
936         Opt_ignore,
937         Opt_err,
938 };
939 
940 static const match_table_t tokens = {
941         {Opt_fast_unmount, "fast_unmount"},
942         {Opt_norm_unmount, "norm_unmount"},
943         {Opt_bulk_read, "bulk_read"},
944         {Opt_no_bulk_read, "no_bulk_read"},
945         {Opt_chk_data_crc, "chk_data_crc"},
946         {Opt_no_chk_data_crc, "no_chk_data_crc"},
947         {Opt_override_compr, "compr=%s"},
948         {Opt_ignore, "ubi=%s"},
949         {Opt_ignore, "vol=%s"},
950         {Opt_err, NULL},
951 };
952 
953 /**
954  * parse_standard_option - parse a standard mount option.
955  * @option: the option to parse
956  *
957  * Normally, standard mount options like "sync" are passed to file-systems as
958  * flags. However, when a "rootflags=" kernel boot parameter is used, they may
959  * be present in the options string. This function tries to deal with this
960  * situation and parse standard options. Returns 0 if the option was not
961  * recognized, and the corresponding integer flag if it was.
962  *
963  * UBIFS is only interested in the "sync" option, so do not check for anything
964  * else.
965  */
966 static int parse_standard_option(const char *option)
967 {
968 
969         pr_notice("UBIFS: parse %s\n", option);
970         if (!strcmp(option, "sync"))
971                 return MS_SYNCHRONOUS;
972         return 0;
973 }
974 
975 /**
976  * ubifs_parse_options - parse mount parameters.
977  * @c: UBIFS file-system description object
978  * @options: parameters to parse
979  * @is_remount: non-zero if this is FS re-mount
980  *
981  * This function parses UBIFS mount options and returns zero in case success
982  * and a negative error code in case of failure.
983  */
984 static int ubifs_parse_options(struct ubifs_info *c, char *options,
985                                int is_remount)
986 {
987         char *p;
988         substring_t args[MAX_OPT_ARGS];
989 
990         if (!options)
991                 return 0;
992 
993         while ((p = strsep(&options, ","))) {
994                 int token;
995 
996                 if (!*p)
997                         continue;
998 
999                 token = match_token(p, tokens, args);
1000                 switch (token) {
1001                 /*
1002                  * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
1003                  * We accept them in order to be backward-compatible. But this
1004                  * should be removed at some point.
1005                  */
1006                 case Opt_fast_unmount:
1007                         c->mount_opts.unmount_mode = 2;
1008                         break;
1009                 case Opt_norm_unmount:
1010                         c->mount_opts.unmount_mode = 1;
1011                         break;
1012                 case Opt_bulk_read:
1013                         c->mount_opts.bulk_read = 2;
1014                         c->bulk_read = 1;
1015                         break;
1016                 case Opt_no_bulk_read:
1017                         c->mount_opts.bulk_read = 1;
1018                         c->bulk_read = 0;
1019                         break;
1020                 case Opt_chk_data_crc:
1021                         c->mount_opts.chk_data_crc = 2;
1022                         c->no_chk_data_crc = 0;
1023                         break;
1024                 case Opt_no_chk_data_crc:
1025                         c->mount_opts.chk_data_crc = 1;
1026                         c->no_chk_data_crc = 1;
1027                         break;
1028                 case Opt_override_compr:
1029                 {
1030                         char *name = match_strdup(&args[0]);
1031 
1032                         if (!name)
1033                                 return -ENOMEM;
1034                         if (!strcmp(name, "none"))
1035                                 c->mount_opts.compr_type = UBIFS_COMPR_NONE;
1036                         else if (!strcmp(name, "lzo"))
1037                                 c->mount_opts.compr_type = UBIFS_COMPR_LZO;
1038                         else if (!strcmp(name, "zlib"))
1039                                 c->mount_opts.compr_type = UBIFS_COMPR_ZLIB;
1040                         else {
1041                                 ubifs_err(c, "unknown compressor \"%s\"", name); //FIXME: is c ready?
1042                                 kfree(name);
1043                                 return -EINVAL;
1044                         }
1045                         kfree(name);
1046                         c->mount_opts.override_compr = 1;
1047                         c->default_compr = c->mount_opts.compr_type;
1048                         break;
1049                 }
1050                 case Opt_ignore:
1051                         break;
1052                 default:
1053                 {
1054                         unsigned long flag;
1055                         struct super_block *sb = c->vfs_sb;
1056 
1057                         flag = parse_standard_option(p);
1058                         if (!flag) {
1059                                 ubifs_err(c, "unrecognized mount option \"%s\" or missing value",
1060                                           p);
1061                                 return -EINVAL;
1062                         }
1063                         sb->s_flags |= flag;
1064                         break;
1065                 }
1066                 }
1067         }
1068 
1069         return 0;
1070 }
1071 
1072 /**
1073  * destroy_journal - destroy journal data structures.
1074  * @c: UBIFS file-system description object
1075  *
1076  * This function destroys journal data structures including those that may have
1077  * been created by recovery functions.
1078  */
1079 static void destroy_journal(struct ubifs_info *c)
1080 {
1081         while (!list_empty(&c->unclean_leb_list)) {
1082                 struct ubifs_unclean_leb *ucleb;
1083 
1084                 ucleb = list_entry(c->unclean_leb_list.next,
1085                                    struct ubifs_unclean_leb, list);
1086                 list_del(&ucleb->list);
1087                 kfree(ucleb);
1088         }
1089         while (!list_empty(&c->old_buds)) {
1090                 struct ubifs_bud *bud;
1091 
1092                 bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
1093                 list_del(&bud->list);
1094                 kfree(bud);
1095         }
1096         ubifs_destroy_idx_gc(c);
1097         ubifs_destroy_size_tree(c);
1098         ubifs_tnc_close(c);
1099         free_buds(c);
1100 }
1101 
1102 /**
1103  * bu_init - initialize bulk-read information.
1104  * @c: UBIFS file-system description object
1105  */
1106 static void bu_init(struct ubifs_info *c)
1107 {
1108         ubifs_assert(c->bulk_read == 1);
1109 
1110         if (c->bu.buf)
1111                 return; /* Already initialized */
1112 
1113 again:
1114         c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN);
1115         if (!c->bu.buf) {
1116                 if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {
1117                         c->max_bu_buf_len = UBIFS_KMALLOC_OK;
1118                         goto again;
1119                 }
1120 
1121                 /* Just disable bulk-read */
1122                 ubifs_warn(c, "cannot allocate %d bytes of memory for bulk-read, disabling it",
1123                            c->max_bu_buf_len);
1124                 c->mount_opts.bulk_read = 1;
1125                 c->bulk_read = 0;
1126                 return;
1127         }
1128 }
1129 
1130 /**
1131  * check_free_space - check if there is enough free space to mount.
1132  * @c: UBIFS file-system description object
1133  *
1134  * This function makes sure UBIFS has enough free space to be mounted in
1135  * read/write mode. UBIFS must always have some free space to allow deletions.
1136  */
1137 static int check_free_space(struct ubifs_info *c)
1138 {
1139         ubifs_assert(c->dark_wm > 0);
1140         if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
1141                 ubifs_err(c, "insufficient free space to mount in R/W mode");
1142                 ubifs_dump_budg(c, &c->bi);
1143                 ubifs_dump_lprops(c);
1144                 return -ENOSPC;
1145         }
1146         return 0;
1147 }
1148 
1149 /**
1150  * mount_ubifs - mount UBIFS file-system.
1151  * @c: UBIFS file-system description object
1152  *
1153  * This function mounts UBIFS file system. Returns zero in case of success and
1154  * a negative error code in case of failure.
1155  */
1156 static int mount_ubifs(struct ubifs_info *c)
1157 {
1158         int err;
1159         long long x, y;
1160         size_t sz;
1161 
1162         c->ro_mount = !!(c->vfs_sb->s_flags & MS_RDONLY);
1163         /* Suppress error messages while probing if MS_SILENT is set */
1164         c->probing = !!(c->vfs_sb->s_flags & MS_SILENT);
1165 
1166         err = init_constants_early(c);
1167         if (err)
1168                 return err;
1169 
1170         err = ubifs_debugging_init(c);
1171         if (err)
1172                 return err;
1173 
1174         err = check_volume_empty(c);
1175         if (err)
1176                 goto out_free;
1177 
1178         if (c->empty && (c->ro_mount || c->ro_media)) {
1179                 /*
1180                  * This UBI volume is empty, and read-only, or the file system
1181                  * is mounted read-only - we cannot format it.
1182                  */
1183                 ubifs_err(c, "can't format empty UBI volume: read-only %s",
1184                           c->ro_media ? "UBI volume" : "mount");
1185                 err = -EROFS;
1186                 goto out_free;
1187         }
1188 
1189         if (c->ro_media && !c->ro_mount) {
1190                 ubifs_err(c, "cannot mount read-write - read-only media");
1191                 err = -EROFS;
1192                 goto out_free;
1193         }
1194 
1195         /*
1196          * The requirement for the buffer is that it should fit indexing B-tree
1197          * height amount of integers. We assume the height if the TNC tree will
1198          * never exceed 64.
1199          */
1200         err = -ENOMEM;
1201         c->bottom_up_buf = kmalloc(BOTTOM_UP_HEIGHT * sizeof(int), GFP_KERNEL);
1202         if (!c->bottom_up_buf)
1203                 goto out_free;
1204 
1205         c->sbuf = vmalloc(c->leb_size);
1206         if (!c->sbuf)
1207                 goto out_free;
1208 
1209         if (!c->ro_mount) {
1210                 c->ileb_buf = vmalloc(c->leb_size);
1211                 if (!c->ileb_buf)
1212                         goto out_free;
1213         }
1214 
1215         if (c->bulk_read == 1)
1216                 bu_init(c);
1217 
1218         if (!c->ro_mount) {
1219                 c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
1220                                                UBIFS_CIPHER_BLOCK_SIZE,
1221                                                GFP_KERNEL);
1222                 if (!c->write_reserve_buf)
1223                         goto out_free;
1224         }
1225 
1226         c->mounting = 1;
1227 
1228         err = ubifs_read_superblock(c);
1229         if (err)
1230                 goto out_free;
1231 
1232         c->probing = 0;
1233 
1234         /*
1235          * Make sure the compressor which is set as default in the superblock
1236          * or overridden by mount options is actually compiled in.
1237          */
1238         if (!ubifs_compr_present(c->default_compr)) {
1239                 ubifs_err(c, "'compressor \"%s\" is not compiled in",
1240                           ubifs_compr_name(c->default_compr));
1241                 err = -ENOTSUPP;
1242                 goto out_free;
1243         }
1244 
1245         err = init_constants_sb(c);
1246         if (err)
1247                 goto out_free;
1248 
1249         sz = ALIGN(c->max_idx_node_sz, c->min_io_size);
1250         sz = ALIGN(sz + c->max_idx_node_sz, c->min_io_size);
1251         c->cbuf = kmalloc(sz, GFP_NOFS);
1252         if (!c->cbuf) {
1253                 err = -ENOMEM;
1254                 goto out_free;
1255         }
1256 
1257         err = alloc_wbufs(c);
1258         if (err)
1259                 goto out_cbuf;
1260 
1261         sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
1262         if (!c->ro_mount) {
1263                 /* Create background thread */
1264                 c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1265                 if (IS_ERR(c->bgt)) {
1266                         err = PTR_ERR(c->bgt);
1267                         c->bgt = NULL;
1268                         ubifs_err(c, "cannot spawn \"%s\", error %d",
1269                                   c->bgt_name, err);
1270                         goto out_wbufs;
1271                 }
1272                 wake_up_process(c->bgt);
1273         }
1274 
1275         err = ubifs_read_master(c);
1276         if (err)
1277                 goto out_master;
1278 
1279         init_constants_master(c);
1280 
1281         if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
1282                 ubifs_msg(c, "recovery needed");
1283                 c->need_recovery = 1;
1284         }
1285 
1286         if (c->need_recovery && !c->ro_mount) {
1287                 err = ubifs_recover_inl_heads(c, c->sbuf);
1288                 if (err)
1289                         goto out_master;
1290         }
1291 
1292         err = ubifs_lpt_init(c, 1, !c->ro_mount);
1293         if (err)
1294                 goto out_master;
1295 
1296         if (!c->ro_mount && c->space_fixup) {
1297                 err = ubifs_fixup_free_space(c);
1298                 if (err)
1299                         goto out_lpt;
1300         }
1301 
1302         if (!c->ro_mount && !c->need_recovery) {
1303                 /*
1304                  * Set the "dirty" flag so that if we reboot uncleanly we
1305                  * will notice this immediately on the next mount.
1306                  */
1307                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1308                 err = ubifs_write_master(c);
1309                 if (err)
1310                         goto out_lpt;
1311         }
1312 
1313         err = dbg_check_idx_size(c, c->bi.old_idx_sz);
1314         if (err)
1315                 goto out_lpt;
1316 
1317         err = ubifs_replay_journal(c);
1318         if (err)
1319                 goto out_journal;
1320 
1321         /* Calculate 'min_idx_lebs' after journal replay */
1322         c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
1323 
1324         err = ubifs_mount_orphans(c, c->need_recovery, c->ro_mount);
1325         if (err)
1326                 goto out_orphans;
1327 
1328         if (!c->ro_mount) {
1329                 int lnum;
1330 
1331                 err = check_free_space(c);
1332                 if (err)
1333                         goto out_orphans;
1334 
1335                 /* Check for enough log space */
1336                 lnum = c->lhead_lnum + 1;
1337                 if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1338                         lnum = UBIFS_LOG_LNUM;
1339                 if (lnum == c->ltail_lnum) {
1340                         err = ubifs_consolidate_log(c);
1341                         if (err)
1342                                 goto out_orphans;
1343                 }
1344 
1345                 if (c->need_recovery) {
1346                         err = ubifs_recover_size(c);
1347                         if (err)
1348                                 goto out_orphans;
1349                         err = ubifs_rcvry_gc_commit(c);
1350                         if (err)
1351                                 goto out_orphans;
1352                 } else {
1353                         err = take_gc_lnum(c);
1354                         if (err)
1355                                 goto out_orphans;
1356 
1357                         /*
1358                          * GC LEB may contain garbage if there was an unclean
1359                          * reboot, and it should be un-mapped.
1360                          */
1361                         err = ubifs_leb_unmap(c, c->gc_lnum);
1362                         if (err)
1363                                 goto out_orphans;
1364                 }
1365 
1366                 err = dbg_check_lprops(c);
1367                 if (err)
1368                         goto out_orphans;
1369         } else if (c->need_recovery) {
1370                 err = ubifs_recover_size(c);
1371                 if (err)
1372                         goto out_orphans;
1373         } else {
1374                 /*
1375                  * Even if we mount read-only, we have to set space in GC LEB
1376                  * to proper value because this affects UBIFS free space
1377                  * reporting. We do not want to have a situation when
1378                  * re-mounting from R/O to R/W changes amount of free space.
1379                  */
1380                 err = take_gc_lnum(c);
1381                 if (err)
1382                         goto out_orphans;
1383         }
1384 
1385         spin_lock(&ubifs_infos_lock);
1386         list_add_tail(&c->infos_list, &ubifs_infos);
1387         spin_unlock(&ubifs_infos_lock);
1388 
1389         if (c->need_recovery) {
1390                 if (c->ro_mount)
1391                         ubifs_msg(c, "recovery deferred");
1392                 else {
1393                         c->need_recovery = 0;
1394                         ubifs_msg(c, "recovery completed");
1395                         /*
1396                          * GC LEB has to be empty and taken at this point. But
1397                          * the journal head LEBs may also be accounted as
1398                          * "empty taken" if they are empty.
1399                          */
1400                         ubifs_assert(c->lst.taken_empty_lebs > 0);
1401                 }
1402         } else
1403                 ubifs_assert(c->lst.taken_empty_lebs > 0);
1404 
1405         err = dbg_check_filesystem(c);
1406         if (err)
1407                 goto out_infos;
1408 
1409         err = dbg_debugfs_init_fs(c);
1410         if (err)
1411                 goto out_infos;
1412 
1413         c->mounting = 0;
1414 
1415         ubifs_msg(c, "UBIFS: mounted UBI device %d, volume %d, name \"%s\"%s",
1416                   c->vi.ubi_num, c->vi.vol_id, c->vi.name,
1417                   c->ro_mount ? ", R/O mode" : "");
1418         x = (long long)c->main_lebs * c->leb_size;
1419         y = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
1420         ubifs_msg(c, "LEB size: %d bytes (%d KiB), min./max. I/O unit sizes: %d bytes/%d bytes",
1421                   c->leb_size, c->leb_size >> 10, c->min_io_size,
1422                   c->max_write_size);
1423         ubifs_msg(c, "FS size: %lld bytes (%lld MiB, %d LEBs), journal size %lld bytes (%lld MiB, %d LEBs)",
1424                   x, x >> 20, c->main_lebs,
1425                   y, y >> 20, c->log_lebs + c->max_bud_cnt);
1426         ubifs_msg(c, "reserved for root: %llu bytes (%llu KiB)",
1427                   c->report_rp_size, c->report_rp_size >> 10);
1428         ubifs_msg(c, "media format: w%d/r%d (latest is w%d/r%d), UUID %pUB%s",
1429                   c->fmt_version, c->ro_compat_version,
1430                   UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION, c->uuid,
1431                   c->big_lpt ? ", big LPT model" : ", small LPT model");
1432 
1433         dbg_gen("default compressor:  %s", ubifs_compr_name(c->default_compr));
1434         dbg_gen("data journal heads:  %d",
1435                 c->jhead_cnt - NONDATA_JHEADS_CNT);
1436         dbg_gen("log LEBs:            %d (%d - %d)",
1437                 c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
1438         dbg_gen("LPT area LEBs:       %d (%d - %d)",
1439                 c->lpt_lebs, c->lpt_first, c->lpt_last);
1440         dbg_gen("orphan area LEBs:    %d (%d - %d)",
1441                 c->orph_lebs, c->orph_first, c->orph_last);
1442         dbg_gen("main area LEBs:      %d (%d - %d)",
1443                 c->main_lebs, c->main_first, c->leb_cnt - 1);
1444         dbg_gen("index LEBs:          %d", c->lst.idx_lebs);
1445         dbg_gen("total index bytes:   %lld (%lld KiB, %lld MiB)",
1446                 c->bi.old_idx_sz, c->bi.old_idx_sz >> 10,
1447                 c->bi.old_idx_sz >> 20);
1448         dbg_gen("key hash type:       %d", c->key_hash_type);
1449         dbg_gen("tree fanout:         %d", c->fanout);
1450         dbg_gen("reserved GC LEB:     %d", c->gc_lnum);
1451         dbg_gen("max. znode size      %d", c->max_znode_sz);
1452         dbg_gen("max. index node size %d", c->max_idx_node_sz);
1453         dbg_gen("node sizes:          data %zu, inode %zu, dentry %zu",
1454                 UBIFS_DATA_NODE_SZ, UBIFS_INO_NODE_SZ, UBIFS_DENT_NODE_SZ);
1455         dbg_gen("node sizes:          trun %zu, sb %zu, master %zu",
1456                 UBIFS_TRUN_NODE_SZ, UBIFS_SB_NODE_SZ, UBIFS_MST_NODE_SZ);
1457         dbg_gen("node sizes:          ref %zu, cmt. start %zu, orph %zu",
1458                 UBIFS_REF_NODE_SZ, UBIFS_CS_NODE_SZ, UBIFS_ORPH_NODE_SZ);
1459         dbg_gen("max. node sizes:     data %zu, inode %zu dentry %zu, idx %d",
1460                 UBIFS_MAX_DATA_NODE_SZ, UBIFS_MAX_INO_NODE_SZ,
1461                 UBIFS_MAX_DENT_NODE_SZ, ubifs_idx_node_sz(c, c->fanout));
1462         dbg_gen("dead watermark:      %d", c->dead_wm);
1463         dbg_gen("dark watermark:      %d", c->dark_wm);
1464         dbg_gen("LEB overhead:        %d", c->leb_overhead);
1465         x = (long long)c->main_lebs * c->dark_wm;
1466         dbg_gen("max. dark space:     %lld (%lld KiB, %lld MiB)",
1467                 x, x >> 10, x >> 20);
1468         dbg_gen("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
1469                 c->max_bud_bytes, c->max_bud_bytes >> 10,
1470                 c->max_bud_bytes >> 20);
1471         dbg_gen("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
1472                 c->bg_bud_bytes, c->bg_bud_bytes >> 10,
1473                 c->bg_bud_bytes >> 20);
1474         dbg_gen("current bud bytes    %lld (%lld KiB, %lld MiB)",
1475                 c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
1476         dbg_gen("max. seq. number:    %llu", c->max_sqnum);
1477         dbg_gen("commit number:       %llu", c->cmt_no);
1478 
1479         return 0;
1480 
1481 out_infos:
1482         spin_lock(&ubifs_infos_lock);
1483         list_del(&c->infos_list);
1484         spin_unlock(&ubifs_infos_lock);
1485 out_orphans:
1486         free_orphans(c);
1487 out_journal:
1488         destroy_journal(c);
1489 out_lpt:
1490         ubifs_lpt_free(c, 0);
1491 out_master:
1492         kfree(c->mst_node);
1493         kfree(c->rcvrd_mst_node);
1494         if (c->bgt)
1495                 kthread_stop(c->bgt);
1496 out_wbufs:
1497         free_wbufs(c);
1498 out_cbuf:
1499         kfree(c->cbuf);
1500 out_free:
1501         kfree(c->write_reserve_buf);
1502         kfree(c->bu.buf);
1503         vfree(c->ileb_buf);
1504         vfree(c->sbuf);
1505         kfree(c->bottom_up_buf);
1506         ubifs_debugging_exit(c);
1507         return err;
1508 }
1509 
1510 /**
1511  * ubifs_umount - un-mount UBIFS file-system.
1512  * @c: UBIFS file-system description object
1513  *
1514  * Note, this function is called to free allocated resourced when un-mounting,
1515  * as well as free resources when an error occurred while we were half way
1516  * through mounting (error path cleanup function). So it has to make sure the
1517  * resource was actually allocated before freeing it.
1518  */
1519 static void ubifs_umount(struct ubifs_info *c)
1520 {
1521         dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
1522                 c->vi.vol_id);
1523 
1524         dbg_debugfs_exit_fs(c);
1525         spin_lock(&ubifs_infos_lock);
1526         list_del(&c->infos_list);
1527         spin_unlock(&ubifs_infos_lock);
1528 
1529         if (c->bgt)
1530                 kthread_stop(c->bgt);
1531 
1532         destroy_journal(c);
1533         free_wbufs(c);
1534         free_orphans(c);
1535         ubifs_lpt_free(c, 0);
1536 
1537         kfree(c->cbuf);
1538         kfree(c->rcvrd_mst_node);
1539         kfree(c->mst_node);
1540         kfree(c->write_reserve_buf);
1541         kfree(c->bu.buf);
1542         vfree(c->ileb_buf);
1543         vfree(c->sbuf);
1544         kfree(c->bottom_up_buf);
1545         ubifs_debugging_exit(c);
1546 }
1547 
1548 /**
1549  * ubifs_remount_rw - re-mount in read-write mode.
1550  * @c: UBIFS file-system description object
1551  *
1552  * UBIFS avoids allocating many unnecessary resources when mounted in read-only
1553  * mode. This function allocates the needed resources and re-mounts UBIFS in
1554  * read-write mode.
1555  */
1556 static int ubifs_remount_rw(struct ubifs_info *c)
1557 {
1558         int err, lnum;
1559 
1560         if (c->rw_incompat) {
1561                 ubifs_err(c, "the file-system is not R/W-compatible");
1562                 ubifs_msg(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
1563                           c->fmt_version, c->ro_compat_version,
1564                           UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
1565                 return -EROFS;
1566         }
1567 
1568         mutex_lock(&c->umount_mutex);
1569         dbg_save_space_info(c);
1570         c->remounting_rw = 1;
1571         c->ro_mount = 0;
1572 
1573         if (c->space_fixup) {
1574                 err = ubifs_fixup_free_space(c);
1575                 if (err)
1576                         goto out;
1577         }
1578 
1579         err = check_free_space(c);
1580         if (err)
1581                 goto out;
1582 
1583         if (c->old_leb_cnt != c->leb_cnt) {
1584                 struct ubifs_sb_node *sup;
1585 
1586                 sup = ubifs_read_sb_node(c);
1587                 if (IS_ERR(sup)) {
1588                         err = PTR_ERR(sup);
1589                         goto out;
1590                 }
1591                 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
1592                 err = ubifs_write_sb_node(c, sup);
1593                 kfree(sup);
1594                 if (err)
1595                         goto out;
1596         }
1597 
1598         if (c->need_recovery) {
1599                 ubifs_msg(c, "completing deferred recovery");
1600                 err = ubifs_write_rcvrd_mst_node(c);
1601                 if (err)
1602                         goto out;
1603                 err = ubifs_recover_size(c);
1604                 if (err)
1605                         goto out;
1606                 err = ubifs_clean_lebs(c, c->sbuf);
1607                 if (err)
1608                         goto out;
1609                 err = ubifs_recover_inl_heads(c, c->sbuf);
1610                 if (err)
1611                         goto out;
1612         } else {
1613                 /* A readonly mount is not allowed to have orphans */
1614                 ubifs_assert(c->tot_orphans == 0);
1615                 err = ubifs_clear_orphans(c);
1616                 if (err)
1617                         goto out;
1618         }
1619 
1620         if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
1621                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1622                 err = ubifs_write_master(c);
1623                 if (err)
1624                         goto out;
1625         }
1626 
1627         c->ileb_buf = vmalloc(c->leb_size);
1628         if (!c->ileb_buf) {
1629                 err = -ENOMEM;
1630                 goto out;
1631         }
1632 
1633         c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
1634                                        UBIFS_CIPHER_BLOCK_SIZE, GFP_KERNEL);
1635         if (!c->write_reserve_buf) {
1636                 err = -ENOMEM;
1637                 goto out;
1638         }
1639 
1640         err = ubifs_lpt_init(c, 0, 1);
1641         if (err)
1642                 goto out;
1643 
1644         /* Create background thread */
1645         c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1646         if (IS_ERR(c->bgt)) {
1647                 err = PTR_ERR(c->bgt);
1648                 c->bgt = NULL;
1649                 ubifs_err(c, "cannot spawn \"%s\", error %d",
1650                           c->bgt_name, err);
1651                 goto out;
1652         }
1653         wake_up_process(c->bgt);
1654 
1655         c->orph_buf = vmalloc(c->leb_size);
1656         if (!c->orph_buf) {
1657                 err = -ENOMEM;
1658                 goto out;
1659         }
1660 
1661         /* Check for enough log space */
1662         lnum = c->lhead_lnum + 1;
1663         if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1664                 lnum = UBIFS_LOG_LNUM;
1665         if (lnum == c->ltail_lnum) {
1666                 err = ubifs_consolidate_log(c);
1667                 if (err)
1668                         goto out;
1669         }
1670 
1671         if (c->need_recovery)
1672                 err = ubifs_rcvry_gc_commit(c);
1673         else
1674                 err = ubifs_leb_unmap(c, c->gc_lnum);
1675         if (err)
1676                 goto out;
1677 
1678         dbg_gen("re-mounted read-write");
1679         c->remounting_rw = 0;
1680 
1681         if (c->need_recovery) {
1682                 c->need_recovery = 0;
1683                 ubifs_msg(c, "deferred recovery completed");
1684         } else {
1685                 /*
1686                  * Do not run the debugging space check if the were doing
1687                  * recovery, because when we saved the information we had the
1688                  * file-system in a state where the TNC and lprops has been
1689                  * modified in memory, but all the I/O operations (including a
1690                  * commit) were deferred. So the file-system was in
1691                  * "non-committed" state. Now the file-system is in committed
1692                  * state, and of course the amount of free space will change
1693                  * because, for example, the old index size was imprecise.
1694                  */
1695                 err = dbg_check_space_info(c);
1696         }
1697 
1698         mutex_unlock(&c->umount_mutex);
1699         return err;
1700 
1701 out:
1702         c->ro_mount = 1;
1703         vfree(c->orph_buf);
1704         c->orph_buf = NULL;
1705         if (c->bgt) {
1706                 kthread_stop(c->bgt);
1707                 c->bgt = NULL;
1708         }
1709         free_wbufs(c);
1710         kfree(c->write_reserve_buf);
1711         c->write_reserve_buf = NULL;
1712         vfree(c->ileb_buf);
1713         c->ileb_buf = NULL;
1714         ubifs_lpt_free(c, 1);
1715         c->remounting_rw = 0;
1716         mutex_unlock(&c->umount_mutex);
1717         return err;
1718 }
1719 
1720 /**
1721  * ubifs_remount_ro - re-mount in read-only mode.
1722  * @c: UBIFS file-system description object
1723  *
1724  * We assume VFS has stopped writing. Possibly the background thread could be
1725  * running a commit, however kthread_stop will wait in that case.
1726  */
1727 static void ubifs_remount_ro(struct ubifs_info *c)
1728 {
1729         int i, err;
1730 
1731         ubifs_assert(!c->need_recovery);
1732         ubifs_assert(!c->ro_mount);
1733 
1734         mutex_lock(&c->umount_mutex);
1735         if (c->bgt) {
1736                 kthread_stop(c->bgt);
1737                 c->bgt = NULL;
1738         }
1739 
1740         dbg_save_space_info(c);
1741 
1742         for (i = 0; i < c->jhead_cnt; i++)
1743                 ubifs_wbuf_sync(&c->jheads[i].wbuf);
1744 
1745         c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1746         c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1747         c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1748         err = ubifs_write_master(c);
1749         if (err)
1750                 ubifs_ro_mode(c, err);
1751 
1752         vfree(c->orph_buf);
1753         c->orph_buf = NULL;
1754         kfree(c->write_reserve_buf);
1755         c->write_reserve_buf = NULL;
1756         vfree(c->ileb_buf);
1757         c->ileb_buf = NULL;
1758         ubifs_lpt_free(c, 1);
1759         c->ro_mount = 1;
1760         err = dbg_check_space_info(c);
1761         if (err)
1762                 ubifs_ro_mode(c, err);
1763         mutex_unlock(&c->umount_mutex);
1764 }
1765 
1766 static void ubifs_put_super(struct super_block *sb)
1767 {
1768         int i;
1769         struct ubifs_info *c = sb->s_fs_info;
1770 
1771         ubifs_msg(c, "un-mount UBI device %d", c->vi.ubi_num);
1772 
1773         /*
1774          * The following asserts are only valid if there has not been a failure
1775          * of the media. For example, there will be dirty inodes if we failed
1776          * to write them back because of I/O errors.
1777          */
1778         if (!c->ro_error) {
1779                 ubifs_assert(c->bi.idx_growth == 0);
1780                 ubifs_assert(c->bi.dd_growth == 0);
1781                 ubifs_assert(c->bi.data_growth == 0);
1782         }
1783 
1784         /*
1785          * The 'c->umount_lock' prevents races between UBIFS memory shrinker
1786          * and file system un-mount. Namely, it prevents the shrinker from
1787          * picking this superblock for shrinking - it will be just skipped if
1788          * the mutex is locked.
1789          */
1790         mutex_lock(&c->umount_mutex);
1791         if (!c->ro_mount) {
1792                 /*
1793                  * First of all kill the background thread to make sure it does
1794                  * not interfere with un-mounting and freeing resources.
1795                  */
1796                 if (c->bgt) {
1797                         kthread_stop(c->bgt);
1798                         c->bgt = NULL;
1799                 }
1800 
1801                 /*
1802                  * On fatal errors c->ro_error is set to 1, in which case we do
1803                  * not write the master node.
1804                  */
1805                 if (!c->ro_error) {
1806                         int err;
1807 
1808                         /* Synchronize write-buffers */
1809                         for (i = 0; i < c->jhead_cnt; i++)
1810                                 ubifs_wbuf_sync(&c->jheads[i].wbuf);
1811 
1812                         /*
1813                          * We are being cleanly unmounted which means the
1814                          * orphans were killed - indicate this in the master
1815                          * node. Also save the reserved GC LEB number.
1816                          */
1817                         c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1818                         c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1819                         c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1820                         err = ubifs_write_master(c);
1821                         if (err)
1822                                 /*
1823                                  * Recovery will attempt to fix the master area
1824                                  * next mount, so we just print a message and
1825                                  * continue to unmount normally.
1826                                  */
1827                                 ubifs_err(c, "failed to write master node, error %d",
1828                                           err);
1829                 } else {
1830                         for (i = 0; i < c->jhead_cnt; i++)
1831                                 /* Make sure write-buffer timers are canceled */
1832                                 hrtimer_cancel(&c->jheads[i].wbuf.timer);
1833                 }
1834         }
1835 
1836         ubifs_umount(c);
1837         ubi_close_volume(c->ubi);
1838         mutex_unlock(&c->umount_mutex);
1839 }
1840 
1841 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
1842 {
1843         int err;
1844         struct ubifs_info *c = sb->s_fs_info;
1845 
1846         sync_filesystem(sb);
1847         dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
1848 
1849         err = ubifs_parse_options(c, data, 1);
1850         if (err) {
1851                 ubifs_err(c, "invalid or unknown remount parameter");
1852                 return err;
1853         }
1854 
1855         if (c->ro_mount && !(*flags & MS_RDONLY)) {
1856                 if (c->ro_error) {
1857                         ubifs_msg(c, "cannot re-mount R/W due to prior errors");
1858                         return -EROFS;
1859                 }
1860                 if (c->ro_media) {
1861                         ubifs_msg(c, "cannot re-mount R/W - UBI volume is R/O");
1862                         return -EROFS;
1863                 }
1864                 err = ubifs_remount_rw(c);
1865                 if (err)
1866                         return err;
1867         } else if (!c->ro_mount && (*flags & MS_RDONLY)) {
1868                 if (c->ro_error) {
1869                         ubifs_msg(c, "cannot re-mount R/O due to prior errors");
1870                         return -EROFS;
1871                 }
1872                 ubifs_remount_ro(c);
1873         }
1874 
1875         if (c->bulk_read == 1)
1876                 bu_init(c);
1877         else {
1878                 dbg_gen("disable bulk-read");
1879                 mutex_lock(&c->bu_mutex);
1880                 kfree(c->bu.buf);
1881                 c->bu.buf = NULL;
1882                 mutex_unlock(&c->bu_mutex);
1883         }
1884 
1885         ubifs_assert(c->lst.taken_empty_lebs > 0);
1886         return 0;
1887 }
1888 
1889 const struct super_operations ubifs_super_operations = {
1890         .alloc_inode   = ubifs_alloc_inode,
1891         .destroy_inode = ubifs_destroy_inode,
1892         .put_super     = ubifs_put_super,
1893         .write_inode   = ubifs_write_inode,
1894         .evict_inode   = ubifs_evict_inode,
1895         .statfs        = ubifs_statfs,
1896         .dirty_inode   = ubifs_dirty_inode,
1897         .remount_fs    = ubifs_remount_fs,
1898         .show_options  = ubifs_show_options,
1899         .sync_fs       = ubifs_sync_fs,
1900 };
1901 
1902 /**
1903  * open_ubi - parse UBI device name string and open the UBI device.
1904  * @name: UBI volume name
1905  * @mode: UBI volume open mode
1906  *
1907  * The primary method of mounting UBIFS is by specifying the UBI volume
1908  * character device node path. However, UBIFS may also be mounted withoug any
1909  * character device node using one of the following methods:
1910  *
1911  * o ubiX_Y    - mount UBI device number X, volume Y;
1912  * o ubiY      - mount UBI device number 0, volume Y;
1913  * o ubiX:NAME - mount UBI device X, volume with name NAME;
1914  * o ubi:NAME  - mount UBI device 0, volume with name NAME.
1915  *
1916  * Alternative '!' separator may be used instead of ':' (because some shells
1917  * like busybox may interpret ':' as an NFS host name separator). This function
1918  * returns UBI volume description object in case of success and a negative
1919  * error code in case of failure.
1920  */
1921 static struct ubi_volume_desc *open_ubi(const char *name, int mode)
1922 {
1923         struct ubi_volume_desc *ubi;
1924         int dev, vol;
1925         char *endptr;
1926 
1927         /* First, try to open using the device node path method */
1928         ubi = ubi_open_volume_path(name, mode);
1929         if (!IS_ERR(ubi))
1930                 return ubi;
1931 
1932         /* Try the "nodev" method */
1933         if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
1934                 return ERR_PTR(-EINVAL);
1935 
1936         /* ubi:NAME method */
1937         if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
1938                 return ubi_open_volume_nm(0, name + 4, mode);
1939 
1940         if (!isdigit(name[3]))
1941                 return ERR_PTR(-EINVAL);
1942 
1943         dev = simple_strtoul(name + 3, &endptr, 0);
1944 
1945         /* ubiY method */
1946         if (*endptr == '\0')
1947                 return ubi_open_volume(0, dev, mode);
1948 
1949         /* ubiX_Y method */
1950         if (*endptr == '_' && isdigit(endptr[1])) {
1951                 vol = simple_strtoul(endptr + 1, &endptr, 0);
1952                 if (*endptr != '\0')
1953                         return ERR_PTR(-EINVAL);
1954                 return ubi_open_volume(dev, vol, mode);
1955         }
1956 
1957         /* ubiX:NAME method */
1958         if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
1959                 return ubi_open_volume_nm(dev, ++endptr, mode);
1960 
1961         return ERR_PTR(-EINVAL);
1962 }
1963 
1964 static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
1965 {
1966         struct ubifs_info *c;
1967 
1968         c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
1969         if (c) {
1970                 spin_lock_init(&c->cnt_lock);
1971                 spin_lock_init(&c->cs_lock);
1972                 spin_lock_init(&c->buds_lock);
1973                 spin_lock_init(&c->space_lock);
1974                 spin_lock_init(&c->orphan_lock);
1975                 init_rwsem(&c->commit_sem);
1976                 mutex_init(&c->lp_mutex);
1977                 mutex_init(&c->tnc_mutex);
1978                 mutex_init(&c->log_mutex);
1979                 mutex_init(&c->umount_mutex);
1980                 mutex_init(&c->bu_mutex);
1981                 mutex_init(&c->write_reserve_mutex);
1982                 init_waitqueue_head(&c->cmt_wq);
1983                 c->buds = RB_ROOT;
1984                 c->old_idx = RB_ROOT;
1985                 c->size_tree = RB_ROOT;
1986                 c->orph_tree = RB_ROOT;
1987                 INIT_LIST_HEAD(&c->infos_list);
1988                 INIT_LIST_HEAD(&c->idx_gc);
1989                 INIT_LIST_HEAD(&c->replay_list);
1990                 INIT_LIST_HEAD(&c->replay_buds);
1991                 INIT_LIST_HEAD(&c->uncat_list);
1992                 INIT_LIST_HEAD(&c->empty_list);
1993                 INIT_LIST_HEAD(&c->freeable_list);
1994                 INIT_LIST_HEAD(&c->frdi_idx_list);
1995                 INIT_LIST_HEAD(&c->unclean_leb_list);
1996                 INIT_LIST_HEAD(&c->old_buds);
1997                 INIT_LIST_HEAD(&c->orph_list);
1998                 INIT_LIST_HEAD(&c->orph_new);
1999                 c->no_chk_data_crc = 1;
2000 
2001                 c->highest_inum = UBIFS_FIRST_INO;
2002                 c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
2003 
2004                 ubi_get_volume_info(ubi, &c->vi);
2005                 ubi_get_device_info(c->vi.ubi_num, &c->di);
2006         }
2007         return c;
2008 }
2009 
2010 #ifndef CONFIG_UBIFS_FS_ENCRYPTION
2011 const struct fscrypt_operations ubifs_crypt_operations = {
2012         .is_encrypted           = __ubifs_crypt_is_encrypted,
2013 };
2014 #endif
2015 
2016 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
2017 {
2018         struct ubifs_info *c = sb->s_fs_info;
2019         struct inode *root;
2020         int err;
2021 
2022         c->vfs_sb = sb;
2023         /* Re-open the UBI device in read-write mode */
2024         c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
2025         if (IS_ERR(c->ubi)) {
2026                 err = PTR_ERR(c->ubi);
2027                 goto out;
2028         }
2029 
2030         err = ubifs_parse_options(c, data, 0);
2031         if (err)
2032                 goto out_close;
2033 
2034         /*
2035          * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
2036          * UBIFS, I/O is not deferred, it is done immediately in readpage,
2037          * which means the user would have to wait not just for their own I/O
2038          * but the read-ahead I/O as well i.e. completely pointless.
2039          *
2040          * Read-ahead will be disabled because @sb->s_bdi->ra_pages is 0. Also
2041          * @sb->s_bdi->capabilities are initialized to 0 so there won't be any
2042          * writeback happening.
2043          */
2044         err = super_setup_bdi_name(sb, "ubifs_%d_%d", c->vi.ubi_num,
2045                                    c->vi.vol_id);
2046         if (err)
2047                 goto out_close;
2048 
2049         sb->s_fs_info = c;
2050         sb->s_magic = UBIFS_SUPER_MAGIC;
2051         sb->s_blocksize = UBIFS_BLOCK_SIZE;
2052         sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
2053         sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
2054         if (c->max_inode_sz > MAX_LFS_FILESIZE)
2055                 sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
2056         sb->s_op = &ubifs_super_operations;
2057         sb->s_xattr = ubifs_xattr_handlers;
2058         sb->s_cop = &ubifs_crypt_operations;
2059 
2060         mutex_lock(&c->umount_mutex);
2061         err = mount_ubifs(c);
2062         if (err) {
2063                 ubifs_assert(err < 0);
2064                 goto out_unlock;
2065         }
2066 
2067         /* Read the root inode */
2068         root = ubifs_iget(sb, UBIFS_ROOT_INO);
2069         if (IS_ERR(root)) {
2070                 err = PTR_ERR(root);
2071                 goto out_umount;
2072         }
2073 
2074         sb->s_root = d_make_root(root);
2075         if (!sb->s_root) {
2076                 err = -ENOMEM;
2077                 goto out_umount;
2078         }
2079 
2080         mutex_unlock(&c->umount_mutex);
2081         return 0;
2082 
2083 out_umount:
2084         ubifs_umount(c);
2085 out_unlock:
2086         mutex_unlock(&c->umount_mutex);
2087 out_close:
2088         ubi_close_volume(c->ubi);
2089 out:
2090         return err;
2091 }
2092 
2093 static int sb_test(struct super_block *sb, void *data)
2094 {
2095         struct ubifs_info *c1 = data;
2096         struct ubifs_info *c = sb->s_fs_info;
2097 
2098         return c->vi.cdev == c1->vi.cdev;
2099 }
2100 
2101 static int sb_set(struct super_block *sb, void *data)
2102 {
2103         sb->s_fs_info = data;
2104         return set_anon_super(sb, NULL);
2105 }
2106 
2107 static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
2108                         const char *name, void *data)
2109 {
2110         struct ubi_volume_desc *ubi;
2111         struct ubifs_info *c;
2112         struct super_block *sb;
2113         int err;
2114 
2115         dbg_gen("name %s, flags %#x", name, flags);
2116 
2117         /*
2118          * Get UBI device number and volume ID. Mount it read-only so far
2119          * because this might be a new mount point, and UBI allows only one
2120          * read-write user at a time.
2121          */
2122         ubi = open_ubi(name, UBI_READONLY);
2123         if (IS_ERR(ubi)) {
2124                 if (!(flags & MS_SILENT))
2125                         pr_err("UBIFS error (pid: %d): cannot open \"%s\", error %d",
2126                                current->pid, name, (int)PTR_ERR(ubi));
2127                 return ERR_CAST(ubi);
2128         }
2129 
2130         c = alloc_ubifs_info(ubi);
2131         if (!c) {
2132                 err = -ENOMEM;
2133                 goto out_close;
2134         }
2135 
2136         dbg_gen("opened ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
2137 
2138         sb = sget(fs_type, sb_test, sb_set, flags, c);
2139         if (IS_ERR(sb)) {
2140                 err = PTR_ERR(sb);
2141                 kfree(c);
2142                 goto out_close;
2143         }
2144 
2145         if (sb->s_root) {
2146                 struct ubifs_info *c1 = sb->s_fs_info;
2147                 kfree(c);
2148                 /* A new mount point for already mounted UBIFS */
2149                 dbg_gen("this ubi volume is already mounted");
2150                 if (!!(flags & MS_RDONLY) != c1->ro_mount) {
2151                         err = -EBUSY;
2152                         goto out_deact;
2153                 }
2154         } else {
2155                 err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
2156                 if (err)
2157                         goto out_deact;
2158                 /* We do not support atime */
2159                 sb->s_flags |= MS_ACTIVE;
2160 #ifndef CONFIG_UBIFS_ATIME_SUPPORT
2161                 sb->s_flags |= MS_NOATIME;
2162 #else
2163                 ubifs_msg(c, "full atime support is enabled.");
2164 #endif
2165         }
2166 
2167         /* 'fill_super()' opens ubi again so we must close it here */
2168         ubi_close_volume(ubi);
2169 
2170         return dget(sb->s_root);
2171 
2172 out_deact:
2173         deactivate_locked_super(sb);
2174 out_close:
2175         ubi_close_volume(ubi);
2176         return ERR_PTR(err);
2177 }
2178 
2179 static void kill_ubifs_super(struct super_block *s)
2180 {
2181         struct ubifs_info *c = s->s_fs_info;
2182         kill_anon_super(s);
2183         kfree(c);
2184 }
2185 
2186 static struct file_system_type ubifs_fs_type = {
2187         .name    = "ubifs",
2188         .owner   = THIS_MODULE,
2189         .mount   = ubifs_mount,
2190         .kill_sb = kill_ubifs_super,
2191 };
2192 MODULE_ALIAS_FS("ubifs");
2193 
2194 /*
2195  * Inode slab cache constructor.
2196  */
2197 static void inode_slab_ctor(void *obj)
2198 {
2199         struct ubifs_inode *ui = obj;
2200         inode_init_once(&ui->vfs_inode);
2201 }
2202 
2203 static int __init ubifs_init(void)
2204 {
2205         int err;
2206 
2207         BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);
2208 
2209         /* Make sure node sizes are 8-byte aligned */
2210         BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
2211         BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
2212         BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
2213         BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
2214         BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
2215         BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
2216         BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
2217         BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
2218         BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
2219         BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
2220         BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);
2221 
2222         BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
2223         BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
2224         BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
2225         BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
2226         BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
2227         BUILD_BUG_ON(MIN_WRITE_SZ           & 7);
2228 
2229         /* Check min. node size */
2230         BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
2231         BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
2232         BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
2233         BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);
2234 
2235         BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2236         BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2237         BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
2238         BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);
2239 
2240         /* Defined node sizes */
2241         BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
2242         BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
2243         BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
2244         BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
2245 
2246         /*
2247          * We use 2 bit wide bit-fields to store compression type, which should
2248          * be amended if more compressors are added. The bit-fields are:
2249          * @compr_type in 'struct ubifs_inode', @default_compr in
2250          * 'struct ubifs_info' and @compr_type in 'struct ubifs_mount_opts'.
2251          */
2252         BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);
2253 
2254         /*
2255          * We require that PAGE_SIZE is greater-than-or-equal-to
2256          * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
2257          */
2258         if (PAGE_SIZE < UBIFS_BLOCK_SIZE) {
2259                 pr_err("UBIFS error (pid %d): VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
2260                        current->pid, (unsigned int)PAGE_SIZE);
2261                 return -EINVAL;
2262         }
2263 
2264         ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
2265                                 sizeof(struct ubifs_inode), 0,
2266                                 SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT |
2267                                 SLAB_ACCOUNT, &inode_slab_ctor);
2268         if (!ubifs_inode_slab)
2269                 return -ENOMEM;
2270 
2271         err = register_shrinker(&ubifs_shrinker_info);
2272         if (err)
2273                 goto out_slab;
2274 
2275         err = ubifs_compressors_init();
2276         if (err)
2277                 goto out_shrinker;
2278 
2279         err = dbg_debugfs_init();
2280         if (err)
2281                 goto out_compr;
2282 
2283         err = register_filesystem(&ubifs_fs_type);
2284         if (err) {
2285                 pr_err("UBIFS error (pid %d): cannot register file system, error %d",
2286                        current->pid, err);
2287                 goto out_dbg;
2288         }
2289         return 0;
2290 
2291 out_dbg:
2292         dbg_debugfs_exit();
2293 out_compr:
2294         ubifs_compressors_exit();
2295 out_shrinker:
2296         unregister_shrinker(&ubifs_shrinker_info);
2297 out_slab:
2298         kmem_cache_destroy(ubifs_inode_slab);
2299         return err;
2300 }
2301 /* late_initcall to let compressors initialize first */
2302 late_initcall(ubifs_init);
2303 
2304 static void __exit ubifs_exit(void)
2305 {
2306         ubifs_assert(list_empty(&ubifs_infos));
2307         ubifs_assert(atomic_long_read(&ubifs_clean_zn_cnt) == 0);
2308 
2309         dbg_debugfs_exit();
2310         ubifs_compressors_exit();
2311         unregister_shrinker(&ubifs_shrinker_info);
2312 
2313         /*
2314          * Make sure all delayed rcu free inodes are flushed before we
2315          * destroy cache.
2316          */
2317         rcu_barrier();
2318         kmem_cache_destroy(ubifs_inode_slab);
2319         unregister_filesystem(&ubifs_fs_type);
2320 }
2321 module_exit(ubifs_exit);
2322 
2323 MODULE_LICENSE("GPL");
2324 MODULE_VERSION(__stringify(UBIFS_VERSION));
2325 MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
2326 MODULE_DESCRIPTION("UBIFS - UBI File System");
2327 

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