~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/ubifs/super.c

Version: ~ [ linux-5.6-rc3 ] ~ [ linux-5.5.7 ] ~ [ linux-5.4.23 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.107 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.172 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.215 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.215 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp