Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/fs/ubifs/super.c

  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 >= 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_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("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_puts(s, ",fast_unmount");
428         else if (c->mount_opts.unmount_mode == 1)
429                 seq_puts(s, ",norm_unmount");
430 
431         if (c->mount_opts.bulk_read == 2)
432                 seq_puts(s, ",bulk_read");
433         else if (c->mount_opts.bulk_read == 1)
434                 seq_puts(s, ",no_bulk_read");
435 
436         if (c->mount_opts.chk_data_crc == 2)
437                 seq_puts(s, ",chk_data_crc");
438         else if (c->mount_opts.chk_data_crc == 1)
439                 seq_puts(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 = kcalloc(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 ubifs_bud *bud, *n;
877 
878         rbtree_postorder_for_each_entry_safe(bud, n, &c->buds, rb)
879                 kfree(bud);
880 }
881 
882 /**
883  * check_volume_empty - check if the UBI volume is empty.
884  * @c: UBIFS file-system description object
885  *
886  * This function checks if the UBIFS volume is empty by looking if its LEBs are
887  * mapped or not. The result of checking is stored in the @c->empty variable.
888  * Returns zero in case of success and a negative error code in case of
889  * failure.
890  */
891 static int check_volume_empty(struct ubifs_info *c)
892 {
893         int lnum, err;
894 
895         c->empty = 1;
896         for (lnum = 0; lnum < c->leb_cnt; lnum++) {
897                 err = ubifs_is_mapped(c, lnum);
898                 if (unlikely(err < 0))
899                         return err;
900                 if (err == 1) {
901                         c->empty = 0;
902                         break;
903                 }
904 
905                 cond_resched();
906         }
907 
908         return 0;
909 }
910 
911 /*
912  * UBIFS mount options.
913  *
914  * Opt_fast_unmount: do not run a journal commit before un-mounting
915  * Opt_norm_unmount: run a journal commit before un-mounting
916  * Opt_bulk_read: enable bulk-reads
917  * Opt_no_bulk_read: disable bulk-reads
918  * Opt_chk_data_crc: check CRCs when reading data nodes
919  * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
920  * Opt_override_compr: override default compressor
921  * Opt_err: just end of array marker
922  */
923 enum {
924         Opt_fast_unmount,
925         Opt_norm_unmount,
926         Opt_bulk_read,
927         Opt_no_bulk_read,
928         Opt_chk_data_crc,
929         Opt_no_chk_data_crc,
930         Opt_override_compr,
931         Opt_err,
932 };
933 
934 static const match_table_t tokens = {
935         {Opt_fast_unmount, "fast_unmount"},
936         {Opt_norm_unmount, "norm_unmount"},
937         {Opt_bulk_read, "bulk_read"},
938         {Opt_no_bulk_read, "no_bulk_read"},
939         {Opt_chk_data_crc, "chk_data_crc"},
940         {Opt_no_chk_data_crc, "no_chk_data_crc"},
941         {Opt_override_compr, "compr=%s"},
942         {Opt_err, NULL},
943 };
944 
945 /**
946  * parse_standard_option - parse a standard mount option.
947  * @option: the option to parse
948  *
949  * Normally, standard mount options like "sync" are passed to file-systems as
950  * flags. However, when a "rootflags=" kernel boot parameter is used, they may
951  * be present in the options string. This function tries to deal with this
952  * situation and parse standard options. Returns 0 if the option was not
953  * recognized, and the corresponding integer flag if it was.
954  *
955  * UBIFS is only interested in the "sync" option, so do not check for anything
956  * else.
957  */
958 static int parse_standard_option(const char *option)
959 {
960         ubifs_msg("parse %s", option);
961         if (!strcmp(option, "sync"))
962                 return MS_SYNCHRONOUS;
963         return 0;
964 }
965 
966 /**
967  * ubifs_parse_options - parse mount parameters.
968  * @c: UBIFS file-system description object
969  * @options: parameters to parse
970  * @is_remount: non-zero if this is FS re-mount
971  *
972  * This function parses UBIFS mount options and returns zero in case success
973  * and a negative error code in case of failure.
974  */
975 static int ubifs_parse_options(struct ubifs_info *c, char *options,
976                                int is_remount)
977 {
978         char *p;
979         substring_t args[MAX_OPT_ARGS];
980 
981         if (!options)
982                 return 0;
983 
984         while ((p = strsep(&options, ","))) {
985                 int token;
986 
987                 if (!*p)
988                         continue;
989 
990                 token = match_token(p, tokens, args);
991                 switch (token) {
992                 /*
993                  * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
994                  * We accept them in order to be backward-compatible. But this
995                  * should be removed at some point.
996                  */
997                 case Opt_fast_unmount:
998                         c->mount_opts.unmount_mode = 2;
999                         break;
1000                 case Opt_norm_unmount:
1001                         c->mount_opts.unmount_mode = 1;
1002                         break;
1003                 case Opt_bulk_read:
1004                         c->mount_opts.bulk_read = 2;
1005                         c->bulk_read = 1;
1006                         break;
1007                 case Opt_no_bulk_read:
1008                         c->mount_opts.bulk_read = 1;
1009                         c->bulk_read = 0;
1010                         break;
1011                 case Opt_chk_data_crc:
1012                         c->mount_opts.chk_data_crc = 2;
1013                         c->no_chk_data_crc = 0;
1014                         break;
1015                 case Opt_no_chk_data_crc:
1016                         c->mount_opts.chk_data_crc = 1;
1017                         c->no_chk_data_crc = 1;
1018                         break;
1019                 case Opt_override_compr:
1020                 {
1021                         char *name = match_strdup(&args[0]);
1022 
1023                         if (!name)
1024                                 return -ENOMEM;
1025                         if (!strcmp(name, "none"))
1026                                 c->mount_opts.compr_type = UBIFS_COMPR_NONE;
1027                         else if (!strcmp(name, "lzo"))
1028                                 c->mount_opts.compr_type = UBIFS_COMPR_LZO;
1029                         else if (!strcmp(name, "zlib"))
1030                                 c->mount_opts.compr_type = UBIFS_COMPR_ZLIB;
1031                         else {
1032                                 ubifs_err("unknown compressor \"%s\"", name);
1033                                 kfree(name);
1034                                 return -EINVAL;
1035                         }
1036                         kfree(name);
1037                         c->mount_opts.override_compr = 1;
1038                         c->default_compr = c->mount_opts.compr_type;
1039                         break;
1040                 }
1041                 default:
1042                 {
1043                         unsigned long flag;
1044                         struct super_block *sb = c->vfs_sb;
1045 
1046                         flag = parse_standard_option(p);
1047                         if (!flag) {
1048                                 ubifs_err("unrecognized mount option \"%s\" or missing value",
1049                                           p);
1050                                 return -EINVAL;
1051                         }
1052                         sb->s_flags |= flag;
1053                         break;
1054                 }
1055                 }
1056         }
1057 
1058         return 0;
1059 }
1060 
1061 /**
1062  * destroy_journal - destroy journal data structures.
1063  * @c: UBIFS file-system description object
1064  *
1065  * This function destroys journal data structures including those that may have
1066  * been created by recovery functions.
1067  */
1068 static void destroy_journal(struct ubifs_info *c)
1069 {
1070         while (!list_empty(&c->unclean_leb_list)) {
1071                 struct ubifs_unclean_leb *ucleb;
1072 
1073                 ucleb = list_entry(c->unclean_leb_list.next,
1074                                    struct ubifs_unclean_leb, list);
1075                 list_del(&ucleb->list);
1076                 kfree(ucleb);
1077         }
1078         while (!list_empty(&c->old_buds)) {
1079                 struct ubifs_bud *bud;
1080 
1081                 bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
1082                 list_del(&bud->list);
1083                 kfree(bud);
1084         }
1085         ubifs_destroy_idx_gc(c);
1086         ubifs_destroy_size_tree(c);
1087         ubifs_tnc_close(c);
1088         free_buds(c);
1089 }
1090 
1091 /**
1092  * bu_init - initialize bulk-read information.
1093  * @c: UBIFS file-system description object
1094  */
1095 static void bu_init(struct ubifs_info *c)
1096 {
1097         ubifs_assert(c->bulk_read == 1);
1098 
1099         if (c->bu.buf)
1100                 return; /* Already initialized */
1101 
1102 again:
1103         c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN);
1104         if (!c->bu.buf) {
1105                 if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {
1106                         c->max_bu_buf_len = UBIFS_KMALLOC_OK;
1107                         goto again;
1108                 }
1109 
1110                 /* Just disable bulk-read */
1111                 ubifs_warn("cannot allocate %d bytes of memory for bulk-read, disabling it",
1112                            c->max_bu_buf_len);
1113                 c->mount_opts.bulk_read = 1;
1114                 c->bulk_read = 0;
1115                 return;
1116         }
1117 }
1118 
1119 /**
1120  * check_free_space - check if there is enough free space to mount.
1121  * @c: UBIFS file-system description object
1122  *
1123  * This function makes sure UBIFS has enough free space to be mounted in
1124  * read/write mode. UBIFS must always have some free space to allow deletions.
1125  */
1126 static int check_free_space(struct ubifs_info *c)
1127 {
1128         ubifs_assert(c->dark_wm > 0);
1129         if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
1130                 ubifs_err("insufficient free space to mount in R/W mode");
1131                 ubifs_dump_budg(c, &c->bi);
1132                 ubifs_dump_lprops(c);
1133                 return -ENOSPC;
1134         }
1135         return 0;
1136 }
1137 
1138 /**
1139  * mount_ubifs - mount UBIFS file-system.
1140  * @c: UBIFS file-system description object
1141  *
1142  * This function mounts UBIFS file system. Returns zero in case of success and
1143  * a negative error code in case of failure.
1144  */
1145 static int mount_ubifs(struct ubifs_info *c)
1146 {
1147         int err;
1148         long long x, y;
1149         size_t sz;
1150 
1151         c->ro_mount = !!(c->vfs_sb->s_flags & MS_RDONLY);
1152         /* Suppress error messages while probing if MS_SILENT is set */
1153         c->probing = !!(c->vfs_sb->s_flags & MS_SILENT);
1154 
1155         err = init_constants_early(c);
1156         if (err)
1157                 return err;
1158 
1159         err = ubifs_debugging_init(c);
1160         if (err)
1161                 return err;
1162 
1163         err = check_volume_empty(c);
1164         if (err)
1165                 goto out_free;
1166 
1167         if (c->empty && (c->ro_mount || c->ro_media)) {
1168                 /*
1169                  * This UBI volume is empty, and read-only, or the file system
1170                  * is mounted read-only - we cannot format it.
1171                  */
1172                 ubifs_err("can't format empty UBI volume: read-only %s",
1173                           c->ro_media ? "UBI volume" : "mount");
1174                 err = -EROFS;
1175                 goto out_free;
1176         }
1177 
1178         if (c->ro_media && !c->ro_mount) {
1179                 ubifs_err("cannot mount read-write - read-only media");
1180                 err = -EROFS;
1181                 goto out_free;
1182         }
1183 
1184         /*
1185          * The requirement for the buffer is that it should fit indexing B-tree
1186          * height amount of integers. We assume the height if the TNC tree will
1187          * never exceed 64.
1188          */
1189         err = -ENOMEM;
1190         c->bottom_up_buf = kmalloc(BOTTOM_UP_HEIGHT * sizeof(int), GFP_KERNEL);
1191         if (!c->bottom_up_buf)
1192                 goto out_free;
1193 
1194         c->sbuf = vmalloc(c->leb_size);
1195         if (!c->sbuf)
1196                 goto out_free;
1197 
1198         if (!c->ro_mount) {
1199                 c->ileb_buf = vmalloc(c->leb_size);
1200                 if (!c->ileb_buf)
1201                         goto out_free;
1202         }
1203 
1204         if (c->bulk_read == 1)
1205                 bu_init(c);
1206 
1207         if (!c->ro_mount) {
1208                 c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ,
1209                                                GFP_KERNEL);
1210                 if (!c->write_reserve_buf)
1211                         goto out_free;
1212         }
1213 
1214         c->mounting = 1;
1215 
1216         err = ubifs_read_superblock(c);
1217         if (err)
1218                 goto out_free;
1219 
1220         c->probing = 0;
1221 
1222         /*
1223          * Make sure the compressor which is set as default in the superblock
1224          * or overridden by mount options is actually compiled in.
1225          */
1226         if (!ubifs_compr_present(c->default_compr)) {
1227                 ubifs_err("'compressor \"%s\" is not compiled in",
1228                           ubifs_compr_name(c->default_compr));
1229                 err = -ENOTSUPP;
1230                 goto out_free;
1231         }
1232 
1233         err = init_constants_sb(c);
1234         if (err)
1235                 goto out_free;
1236 
1237         sz = ALIGN(c->max_idx_node_sz, c->min_io_size);
1238         sz = ALIGN(sz + c->max_idx_node_sz, c->min_io_size);
1239         c->cbuf = kmalloc(sz, GFP_NOFS);
1240         if (!c->cbuf) {
1241                 err = -ENOMEM;
1242                 goto out_free;
1243         }
1244 
1245         err = alloc_wbufs(c);
1246         if (err)
1247                 goto out_cbuf;
1248 
1249         sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
1250         if (!c->ro_mount) {
1251                 /* Create background thread */
1252                 c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1253                 if (IS_ERR(c->bgt)) {
1254                         err = PTR_ERR(c->bgt);
1255                         c->bgt = NULL;
1256                         ubifs_err("cannot spawn \"%s\", error %d",
1257                                   c->bgt_name, err);
1258                         goto out_wbufs;
1259                 }
1260                 wake_up_process(c->bgt);
1261         }
1262 
1263         err = ubifs_read_master(c);
1264         if (err)
1265                 goto out_master;
1266 
1267         init_constants_master(c);
1268 
1269         if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
1270                 ubifs_msg("recovery needed");
1271                 c->need_recovery = 1;
1272         }
1273 
1274         if (c->need_recovery && !c->ro_mount) {
1275                 err = ubifs_recover_inl_heads(c, c->sbuf);
1276                 if (err)
1277                         goto out_master;
1278         }
1279 
1280         err = ubifs_lpt_init(c, 1, !c->ro_mount);
1281         if (err)
1282                 goto out_master;
1283 
1284         if (!c->ro_mount && c->space_fixup) {
1285                 err = ubifs_fixup_free_space(c);
1286                 if (err)
1287                         goto out_lpt;
1288         }
1289 
1290         if (!c->ro_mount) {
1291                 /*
1292                  * Set the "dirty" flag so that if we reboot uncleanly we
1293                  * will notice this immediately on the next mount.
1294                  */
1295                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1296                 err = ubifs_write_master(c);
1297                 if (err)
1298                         goto out_lpt;
1299         }
1300 
1301         err = dbg_check_idx_size(c, c->bi.old_idx_sz);
1302         if (err)
1303                 goto out_lpt;
1304 
1305         err = ubifs_replay_journal(c);
1306         if (err)
1307                 goto out_journal;
1308 
1309         /* Calculate 'min_idx_lebs' after journal replay */
1310         c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
1311 
1312         err = ubifs_mount_orphans(c, c->need_recovery, c->ro_mount);
1313         if (err)
1314                 goto out_orphans;
1315 
1316         if (!c->ro_mount) {
1317                 int lnum;
1318 
1319                 err = check_free_space(c);
1320                 if (err)
1321                         goto out_orphans;
1322 
1323                 /* Check for enough log space */
1324                 lnum = c->lhead_lnum + 1;
1325                 if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1326                         lnum = UBIFS_LOG_LNUM;
1327                 if (lnum == c->ltail_lnum) {
1328                         err = ubifs_consolidate_log(c);
1329                         if (err)
1330                                 goto out_orphans;
1331                 }
1332 
1333                 if (c->need_recovery) {
1334                         err = ubifs_recover_size(c);
1335                         if (err)
1336                                 goto out_orphans;
1337                         err = ubifs_rcvry_gc_commit(c);
1338                         if (err)
1339                                 goto out_orphans;
1340                 } else {
1341                         err = take_gc_lnum(c);
1342                         if (err)
1343                                 goto out_orphans;
1344 
1345                         /*
1346                          * GC LEB may contain garbage if there was an unclean
1347                          * reboot, and it should be un-mapped.
1348                          */
1349                         err = ubifs_leb_unmap(c, c->gc_lnum);
1350                         if (err)
1351                                 goto out_orphans;
1352                 }
1353 
1354                 err = dbg_check_lprops(c);
1355                 if (err)
1356                         goto out_orphans;
1357         } else if (c->need_recovery) {
1358                 err = ubifs_recover_size(c);
1359                 if (err)
1360                         goto out_orphans;
1361         } else {
1362                 /*
1363                  * Even if we mount read-only, we have to set space in GC LEB
1364                  * to proper value because this affects UBIFS free space
1365                  * reporting. We do not want to have a situation when
1366                  * re-mounting from R/O to R/W changes amount of free space.
1367                  */
1368                 err = take_gc_lnum(c);
1369                 if (err)
1370                         goto out_orphans;
1371         }
1372 
1373         spin_lock(&ubifs_infos_lock);
1374         list_add_tail(&c->infos_list, &ubifs_infos);
1375         spin_unlock(&ubifs_infos_lock);
1376 
1377         if (c->need_recovery) {
1378                 if (c->ro_mount)
1379                         ubifs_msg("recovery deferred");
1380                 else {
1381                         c->need_recovery = 0;
1382                         ubifs_msg("recovery completed");
1383                         /*
1384                          * GC LEB has to be empty and taken at this point. But
1385                          * the journal head LEBs may also be accounted as
1386                          * "empty taken" if they are empty.
1387                          */
1388                         ubifs_assert(c->lst.taken_empty_lebs > 0);
1389                 }
1390         } else
1391                 ubifs_assert(c->lst.taken_empty_lebs > 0);
1392 
1393         err = dbg_check_filesystem(c);
1394         if (err)
1395                 goto out_infos;
1396 
1397         err = dbg_debugfs_init_fs(c);
1398         if (err)
1399                 goto out_infos;
1400 
1401         c->mounting = 0;
1402 
1403         ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"%s",
1404                   c->vi.ubi_num, c->vi.vol_id, c->vi.name,
1405                   c->ro_mount ? ", R/O mode" : "");
1406         x = (long long)c->main_lebs * c->leb_size;
1407         y = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
1408         ubifs_msg("LEB size: %d bytes (%d KiB), min./max. I/O unit sizes: %d bytes/%d bytes",
1409                   c->leb_size, c->leb_size >> 10, c->min_io_size,
1410                   c->max_write_size);
1411         ubifs_msg("FS size: %lld bytes (%lld MiB, %d LEBs), journal size %lld bytes (%lld MiB, %d LEBs)",
1412                   x, x >> 20, c->main_lebs,
1413                   y, y >> 20, c->log_lebs + c->max_bud_cnt);
1414         ubifs_msg("reserved for root: %llu bytes (%llu KiB)",
1415                   c->report_rp_size, c->report_rp_size >> 10);
1416         ubifs_msg("media format: w%d/r%d (latest is w%d/r%d), UUID %pUB%s",
1417                   c->fmt_version, c->ro_compat_version,
1418                   UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION, c->uuid,
1419                   c->big_lpt ? ", big LPT model" : ", small LPT model");
1420 
1421         dbg_gen("default compressor:  %s", ubifs_compr_name(c->default_compr));
1422         dbg_gen("data journal heads:  %d",
1423                 c->jhead_cnt - NONDATA_JHEADS_CNT);
1424         dbg_gen("log LEBs:            %d (%d - %d)",
1425                 c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
1426         dbg_gen("LPT area LEBs:       %d (%d - %d)",
1427                 c->lpt_lebs, c->lpt_first, c->lpt_last);
1428         dbg_gen("orphan area LEBs:    %d (%d - %d)",
1429                 c->orph_lebs, c->orph_first, c->orph_last);
1430         dbg_gen("main area LEBs:      %d (%d - %d)",
1431                 c->main_lebs, c->main_first, c->leb_cnt - 1);
1432         dbg_gen("index LEBs:          %d", c->lst.idx_lebs);
1433         dbg_gen("total index bytes:   %lld (%lld KiB, %lld MiB)",
1434                 c->bi.old_idx_sz, c->bi.old_idx_sz >> 10,
1435                 c->bi.old_idx_sz >> 20);
1436         dbg_gen("key hash type:       %d", c->key_hash_type);
1437         dbg_gen("tree fanout:         %d", c->fanout);
1438         dbg_gen("reserved GC LEB:     %d", c->gc_lnum);
1439         dbg_gen("max. znode size      %d", c->max_znode_sz);
1440         dbg_gen("max. index node size %d", c->max_idx_node_sz);
1441         dbg_gen("node sizes:          data %zu, inode %zu, dentry %zu",
1442                 UBIFS_DATA_NODE_SZ, UBIFS_INO_NODE_SZ, UBIFS_DENT_NODE_SZ);
1443         dbg_gen("node sizes:          trun %zu, sb %zu, master %zu",
1444                 UBIFS_TRUN_NODE_SZ, UBIFS_SB_NODE_SZ, UBIFS_MST_NODE_SZ);
1445         dbg_gen("node sizes:          ref %zu, cmt. start %zu, orph %zu",
1446                 UBIFS_REF_NODE_SZ, UBIFS_CS_NODE_SZ, UBIFS_ORPH_NODE_SZ);
1447         dbg_gen("max. node sizes:     data %zu, inode %zu dentry %zu, idx %d",
1448                 UBIFS_MAX_DATA_NODE_SZ, UBIFS_MAX_INO_NODE_SZ,
1449                 UBIFS_MAX_DENT_NODE_SZ, ubifs_idx_node_sz(c, c->fanout));
1450         dbg_gen("dead watermark:      %d", c->dead_wm);
1451         dbg_gen("dark watermark:      %d", c->dark_wm);
1452         dbg_gen("LEB overhead:        %d", c->leb_overhead);
1453         x = (long long)c->main_lebs * c->dark_wm;
1454         dbg_gen("max. dark space:     %lld (%lld KiB, %lld MiB)",
1455                 x, x >> 10, x >> 20);
1456         dbg_gen("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
1457                 c->max_bud_bytes, c->max_bud_bytes >> 10,
1458                 c->max_bud_bytes >> 20);
1459         dbg_gen("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
1460                 c->bg_bud_bytes, c->bg_bud_bytes >> 10,
1461                 c->bg_bud_bytes >> 20);
1462         dbg_gen("current bud bytes    %lld (%lld KiB, %lld MiB)",
1463                 c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
1464         dbg_gen("max. seq. number:    %llu", c->max_sqnum);
1465         dbg_gen("commit number:       %llu", c->cmt_no);
1466 
1467         return 0;
1468 
1469 out_infos:
1470         spin_lock(&ubifs_infos_lock);
1471         list_del(&c->infos_list);
1472         spin_unlock(&ubifs_infos_lock);
1473 out_orphans:
1474         free_orphans(c);
1475 out_journal:
1476         destroy_journal(c);
1477 out_lpt:
1478         ubifs_lpt_free(c, 0);
1479 out_master:
1480         kfree(c->mst_node);
1481         kfree(c->rcvrd_mst_node);
1482         if (c->bgt)
1483                 kthread_stop(c->bgt);
1484 out_wbufs:
1485         free_wbufs(c);
1486 out_cbuf:
1487         kfree(c->cbuf);
1488 out_free:
1489         kfree(c->write_reserve_buf);
1490         kfree(c->bu.buf);
1491         vfree(c->ileb_buf);
1492         vfree(c->sbuf);
1493         kfree(c->bottom_up_buf);
1494         ubifs_debugging_exit(c);
1495         return err;
1496 }
1497 
1498 /**
1499  * ubifs_umount - un-mount UBIFS file-system.
1500  * @c: UBIFS file-system description object
1501  *
1502  * Note, this function is called to free allocated resourced when un-mounting,
1503  * as well as free resources when an error occurred while we were half way
1504  * through mounting (error path cleanup function). So it has to make sure the
1505  * resource was actually allocated before freeing it.
1506  */
1507 static void ubifs_umount(struct ubifs_info *c)
1508 {
1509         dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
1510                 c->vi.vol_id);
1511 
1512         dbg_debugfs_exit_fs(c);
1513         spin_lock(&ubifs_infos_lock);
1514         list_del(&c->infos_list);
1515         spin_unlock(&ubifs_infos_lock);
1516 
1517         if (c->bgt)
1518                 kthread_stop(c->bgt);
1519 
1520         destroy_journal(c);
1521         free_wbufs(c);
1522         free_orphans(c);
1523         ubifs_lpt_free(c, 0);
1524 
1525         kfree(c->cbuf);
1526         kfree(c->rcvrd_mst_node);
1527         kfree(c->mst_node);
1528         kfree(c->write_reserve_buf);
1529         kfree(c->bu.buf);
1530         vfree(c->ileb_buf);
1531         vfree(c->sbuf);
1532         kfree(c->bottom_up_buf);
1533         ubifs_debugging_exit(c);
1534 }
1535 
1536 /**
1537  * ubifs_remount_rw - re-mount in read-write mode.
1538  * @c: UBIFS file-system description object
1539  *
1540  * UBIFS avoids allocating many unnecessary resources when mounted in read-only
1541  * mode. This function allocates the needed resources and re-mounts UBIFS in
1542  * read-write mode.
1543  */
1544 static int ubifs_remount_rw(struct ubifs_info *c)
1545 {
1546         int err, lnum;
1547 
1548         if (c->rw_incompat) {
1549                 ubifs_err("the file-system is not R/W-compatible");
1550                 ubifs_msg("on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
1551                           c->fmt_version, c->ro_compat_version,
1552                           UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
1553                 return -EROFS;
1554         }
1555 
1556         mutex_lock(&c->umount_mutex);
1557         dbg_save_space_info(c);
1558         c->remounting_rw = 1;
1559         c->ro_mount = 0;
1560 
1561         if (c->space_fixup) {
1562                 err = ubifs_fixup_free_space(c);
1563                 if (err)
1564                         goto out;
1565         }
1566 
1567         err = check_free_space(c);
1568         if (err)
1569                 goto out;
1570 
1571         if (c->old_leb_cnt != c->leb_cnt) {
1572                 struct ubifs_sb_node *sup;
1573 
1574                 sup = ubifs_read_sb_node(c);
1575                 if (IS_ERR(sup)) {
1576                         err = PTR_ERR(sup);
1577                         goto out;
1578                 }
1579                 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
1580                 err = ubifs_write_sb_node(c, sup);
1581                 kfree(sup);
1582                 if (err)
1583                         goto out;
1584         }
1585 
1586         if (c->need_recovery) {
1587                 ubifs_msg("completing deferred recovery");
1588                 err = ubifs_write_rcvrd_mst_node(c);
1589                 if (err)
1590                         goto out;
1591                 err = ubifs_recover_size(c);
1592                 if (err)
1593                         goto out;
1594                 err = ubifs_clean_lebs(c, c->sbuf);
1595                 if (err)
1596                         goto out;
1597                 err = ubifs_recover_inl_heads(c, c->sbuf);
1598                 if (err)
1599                         goto out;
1600         } else {
1601                 /* A readonly mount is not allowed to have orphans */
1602                 ubifs_assert(c->tot_orphans == 0);
1603                 err = ubifs_clear_orphans(c);
1604                 if (err)
1605                         goto out;
1606         }
1607 
1608         if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
1609                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1610                 err = ubifs_write_master(c);
1611                 if (err)
1612                         goto out;
1613         }
1614 
1615         c->ileb_buf = vmalloc(c->leb_size);
1616         if (!c->ileb_buf) {
1617                 err = -ENOMEM;
1618                 goto out;
1619         }
1620 
1621         c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ, GFP_KERNEL);
1622         if (!c->write_reserve_buf) {
1623                 err = -ENOMEM;
1624                 goto out;
1625         }
1626 
1627         err = ubifs_lpt_init(c, 0, 1);
1628         if (err)
1629                 goto out;
1630 
1631         /* Create background thread */
1632         c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1633         if (IS_ERR(c->bgt)) {
1634                 err = PTR_ERR(c->bgt);
1635                 c->bgt = NULL;
1636                 ubifs_err("cannot spawn \"%s\", error %d",
1637                           c->bgt_name, err);
1638                 goto out;
1639         }
1640         wake_up_process(c->bgt);
1641 
1642         c->orph_buf = vmalloc(c->leb_size);
1643         if (!c->orph_buf) {
1644                 err = -ENOMEM;
1645                 goto out;
1646         }
1647 
1648         /* Check for enough log space */
1649         lnum = c->lhead_lnum + 1;
1650         if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1651                 lnum = UBIFS_LOG_LNUM;
1652         if (lnum == c->ltail_lnum) {
1653                 err = ubifs_consolidate_log(c);
1654                 if (err)
1655                         goto out;
1656         }
1657 
1658         if (c->need_recovery)
1659                 err = ubifs_rcvry_gc_commit(c);
1660         else
1661                 err = ubifs_leb_unmap(c, c->gc_lnum);
1662         if (err)
1663                 goto out;
1664 
1665         dbg_gen("re-mounted read-write");
1666         c->remounting_rw = 0;
1667 
1668         if (c->need_recovery) {
1669                 c->need_recovery = 0;
1670                 ubifs_msg("deferred recovery completed");
1671         } else {
1672                 /*
1673                  * Do not run the debugging space check if the were doing
1674                  * recovery, because when we saved the information we had the
1675                  * file-system in a state where the TNC and lprops has been
1676                  * modified in memory, but all the I/O operations (including a
1677                  * commit) were deferred. So the file-system was in
1678                  * "non-committed" state. Now the file-system is in committed
1679                  * state, and of course the amount of free space will change
1680                  * because, for example, the old index size was imprecise.
1681                  */
1682                 err = dbg_check_space_info(c);
1683         }
1684 
1685         mutex_unlock(&c->umount_mutex);
1686         return err;
1687 
1688 out:
1689         c->ro_mount = 1;
1690         vfree(c->orph_buf);
1691         c->orph_buf = NULL;
1692         if (c->bgt) {
1693                 kthread_stop(c->bgt);
1694                 c->bgt = NULL;
1695         }
1696         free_wbufs(c);
1697         kfree(c->write_reserve_buf);
1698         c->write_reserve_buf = NULL;
1699         vfree(c->ileb_buf);
1700         c->ileb_buf = NULL;
1701         ubifs_lpt_free(c, 1);
1702         c->remounting_rw = 0;
1703         mutex_unlock(&c->umount_mutex);
1704         return err;
1705 }
1706 
1707 /**
1708  * ubifs_remount_ro - re-mount in read-only mode.
1709  * @c: UBIFS file-system description object
1710  *
1711  * We assume VFS has stopped writing. Possibly the background thread could be
1712  * running a commit, however kthread_stop will wait in that case.
1713  */
1714 static void ubifs_remount_ro(struct ubifs_info *c)
1715 {
1716         int i, err;
1717 
1718         ubifs_assert(!c->need_recovery);
1719         ubifs_assert(!c->ro_mount);
1720 
1721         mutex_lock(&c->umount_mutex);
1722         if (c->bgt) {
1723                 kthread_stop(c->bgt);
1724                 c->bgt = NULL;
1725         }
1726 
1727         dbg_save_space_info(c);
1728 
1729         for (i = 0; i < c->jhead_cnt; i++)
1730                 ubifs_wbuf_sync(&c->jheads[i].wbuf);
1731 
1732         c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1733         c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1734         c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1735         err = ubifs_write_master(c);
1736         if (err)
1737                 ubifs_ro_mode(c, err);
1738 
1739         vfree(c->orph_buf);
1740         c->orph_buf = NULL;
1741         kfree(c->write_reserve_buf);
1742         c->write_reserve_buf = NULL;
1743         vfree(c->ileb_buf);
1744         c->ileb_buf = NULL;
1745         ubifs_lpt_free(c, 1);
1746         c->ro_mount = 1;
1747         err = dbg_check_space_info(c);
1748         if (err)
1749                 ubifs_ro_mode(c, err);
1750         mutex_unlock(&c->umount_mutex);
1751 }
1752 
1753 static void ubifs_put_super(struct super_block *sb)
1754 {
1755         int i;
1756         struct ubifs_info *c = sb->s_fs_info;
1757 
1758         ubifs_msg("un-mount UBI device %d, volume %d", c->vi.ubi_num,
1759                   c->vi.vol_id);
1760 
1761         /*
1762          * The following asserts are only valid if there has not been a failure
1763          * of the media. For example, there will be dirty inodes if we failed
1764          * to write them back because of I/O errors.
1765          */
1766         if (!c->ro_error) {
1767                 ubifs_assert(c->bi.idx_growth == 0);
1768                 ubifs_assert(c->bi.dd_growth == 0);
1769                 ubifs_assert(c->bi.data_growth == 0);
1770         }
1771 
1772         /*
1773          * The 'c->umount_lock' prevents races between UBIFS memory shrinker
1774          * and file system un-mount. Namely, it prevents the shrinker from
1775          * picking this superblock for shrinking - it will be just skipped if
1776          * the mutex is locked.
1777          */
1778         mutex_lock(&c->umount_mutex);
1779         if (!c->ro_mount) {
1780                 /*
1781                  * First of all kill the background thread to make sure it does
1782                  * not interfere with un-mounting and freeing resources.
1783                  */
1784                 if (c->bgt) {
1785                         kthread_stop(c->bgt);
1786                         c->bgt = NULL;
1787                 }
1788 
1789                 /*
1790                  * On fatal errors c->ro_error is set to 1, in which case we do
1791                  * not write the master node.
1792                  */
1793                 if (!c->ro_error) {
1794                         int err;
1795 
1796                         /* Synchronize write-buffers */
1797                         for (i = 0; i < c->jhead_cnt; i++)
1798                                 ubifs_wbuf_sync(&c->jheads[i].wbuf);
1799 
1800                         /*
1801                          * We are being cleanly unmounted which means the
1802                          * orphans were killed - indicate this in the master
1803                          * node. Also save the reserved GC LEB number.
1804                          */
1805                         c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1806                         c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1807                         c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1808                         err = ubifs_write_master(c);
1809                         if (err)
1810                                 /*
1811                                  * Recovery will attempt to fix the master area
1812                                  * next mount, so we just print a message and
1813                                  * continue to unmount normally.
1814                                  */
1815                                 ubifs_err("failed to write master node, error %d",
1816                                           err);
1817                 } else {
1818                         for (i = 0; i < c->jhead_cnt; i++)
1819                                 /* Make sure write-buffer timers are canceled */
1820                                 hrtimer_cancel(&c->jheads[i].wbuf.timer);
1821                 }
1822         }
1823 
1824         ubifs_umount(c);
1825         bdi_destroy(&c->bdi);
1826         ubi_close_volume(c->ubi);
1827         mutex_unlock(&c->umount_mutex);
1828 }
1829 
1830 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
1831 {
1832         int err;
1833         struct ubifs_info *c = sb->s_fs_info;
1834 
1835         sync_filesystem(sb);
1836         dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
1837 
1838         err = ubifs_parse_options(c, data, 1);
1839         if (err) {
1840                 ubifs_err("invalid or unknown remount parameter");
1841                 return err;
1842         }
1843 
1844         if (c->ro_mount && !(*flags & MS_RDONLY)) {
1845                 if (c->ro_error) {
1846                         ubifs_msg("cannot re-mount R/W due to prior errors");
1847                         return -EROFS;
1848                 }
1849                 if (c->ro_media) {
1850                         ubifs_msg("cannot re-mount R/W - UBI volume is R/O");
1851                         return -EROFS;
1852                 }
1853                 err = ubifs_remount_rw(c);
1854                 if (err)
1855                         return err;
1856         } else if (!c->ro_mount && (*flags & MS_RDONLY)) {
1857                 if (c->ro_error) {
1858                         ubifs_msg("cannot re-mount R/O due to prior errors");
1859                         return -EROFS;
1860                 }
1861                 ubifs_remount_ro(c);
1862         }
1863 
1864         if (c->bulk_read == 1)
1865                 bu_init(c);
1866         else {
1867                 dbg_gen("disable bulk-read");
1868                 kfree(c->bu.buf);
1869                 c->bu.buf = NULL;
1870         }
1871 
1872         ubifs_assert(c->lst.taken_empty_lebs > 0);
1873         return 0;
1874 }
1875 
1876 const struct super_operations ubifs_super_operations = {
1877         .alloc_inode   = ubifs_alloc_inode,
1878         .destroy_inode = ubifs_destroy_inode,
1879         .put_super     = ubifs_put_super,
1880         .write_inode   = ubifs_write_inode,
1881         .evict_inode   = ubifs_evict_inode,
1882         .statfs        = ubifs_statfs,
1883         .dirty_inode   = ubifs_dirty_inode,
1884         .remount_fs    = ubifs_remount_fs,
1885         .show_options  = ubifs_show_options,
1886         .sync_fs       = ubifs_sync_fs,
1887 };
1888 
1889 /**
1890  * open_ubi - parse UBI device name string and open the UBI device.
1891  * @name: UBI volume name
1892  * @mode: UBI volume open mode
1893  *
1894  * The primary method of mounting UBIFS is by specifying the UBI volume
1895  * character device node path. However, UBIFS may also be mounted withoug any
1896  * character device node using one of the following methods:
1897  *
1898  * o ubiX_Y    - mount UBI device number X, volume Y;
1899  * o ubiY      - mount UBI device number 0, volume Y;
1900  * o ubiX:NAME - mount UBI device X, volume with name NAME;
1901  * o ubi:NAME  - mount UBI device 0, volume with name NAME.
1902  *
1903  * Alternative '!' separator may be used instead of ':' (because some shells
1904  * like busybox may interpret ':' as an NFS host name separator). This function
1905  * returns UBI volume description object in case of success and a negative
1906  * error code in case of failure.
1907  */
1908 static struct ubi_volume_desc *open_ubi(const char *name, int mode)
1909 {
1910         struct ubi_volume_desc *ubi;
1911         int dev, vol;
1912         char *endptr;
1913 
1914         /* First, try to open using the device node path method */
1915         ubi = ubi_open_volume_path(name, mode);
1916         if (!IS_ERR(ubi))
1917                 return ubi;
1918 
1919         /* Try the "nodev" method */
1920         if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
1921                 return ERR_PTR(-EINVAL);
1922 
1923         /* ubi:NAME method */
1924         if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
1925                 return ubi_open_volume_nm(0, name + 4, mode);
1926 
1927         if (!isdigit(name[3]))
1928                 return ERR_PTR(-EINVAL);
1929 
1930         dev = simple_strtoul(name + 3, &endptr, 0);
1931 
1932         /* ubiY method */
1933         if (*endptr == '\0')
1934                 return ubi_open_volume(0, dev, mode);
1935 
1936         /* ubiX_Y method */
1937         if (*endptr == '_' && isdigit(endptr[1])) {
1938                 vol = simple_strtoul(endptr + 1, &endptr, 0);
1939                 if (*endptr != '\0')
1940                         return ERR_PTR(-EINVAL);
1941                 return ubi_open_volume(dev, vol, mode);
1942         }
1943 
1944         /* ubiX:NAME method */
1945         if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
1946                 return ubi_open_volume_nm(dev, ++endptr, mode);
1947 
1948         return ERR_PTR(-EINVAL);
1949 }
1950 
1951 static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
1952 {
1953         struct ubifs_info *c;
1954 
1955         c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
1956         if (c) {
1957                 spin_lock_init(&c->cnt_lock);
1958                 spin_lock_init(&c->cs_lock);
1959                 spin_lock_init(&c->buds_lock);
1960                 spin_lock_init(&c->space_lock);
1961                 spin_lock_init(&c->orphan_lock);
1962                 init_rwsem(&c->commit_sem);
1963                 mutex_init(&c->lp_mutex);
1964                 mutex_init(&c->tnc_mutex);
1965                 mutex_init(&c->log_mutex);
1966                 mutex_init(&c->umount_mutex);
1967                 mutex_init(&c->bu_mutex);
1968                 mutex_init(&c->write_reserve_mutex);
1969                 init_waitqueue_head(&c->cmt_wq);
1970                 c->buds = RB_ROOT;
1971                 c->old_idx = RB_ROOT;
1972                 c->size_tree = RB_ROOT;
1973                 c->orph_tree = RB_ROOT;
1974                 INIT_LIST_HEAD(&c->infos_list);
1975                 INIT_LIST_HEAD(&c->idx_gc);
1976                 INIT_LIST_HEAD(&c->replay_list);
1977                 INIT_LIST_HEAD(&c->replay_buds);
1978                 INIT_LIST_HEAD(&c->uncat_list);
1979                 INIT_LIST_HEAD(&c->empty_list);
1980                 INIT_LIST_HEAD(&c->freeable_list);
1981                 INIT_LIST_HEAD(&c->frdi_idx_list);
1982                 INIT_LIST_HEAD(&c->unclean_leb_list);
1983                 INIT_LIST_HEAD(&c->old_buds);
1984                 INIT_LIST_HEAD(&c->orph_list);
1985                 INIT_LIST_HEAD(&c->orph_new);
1986                 c->no_chk_data_crc = 1;
1987 
1988                 c->highest_inum = UBIFS_FIRST_INO;
1989                 c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
1990 
1991                 ubi_get_volume_info(ubi, &c->vi);
1992                 ubi_get_device_info(c->vi.ubi_num, &c->di);
1993         }
1994         return c;
1995 }
1996 
1997 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
1998 {
1999         struct ubifs_info *c = sb->s_fs_info;
2000         struct inode *root;
2001         int err;
2002 
2003         c->vfs_sb = sb;
2004         /* Re-open the UBI device in read-write mode */
2005         c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
2006         if (IS_ERR(c->ubi)) {
2007                 err = PTR_ERR(c->ubi);
2008                 goto out;
2009         }
2010 
2011         /*
2012          * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
2013          * UBIFS, I/O is not deferred, it is done immediately in readpage,
2014          * which means the user would have to wait not just for their own I/O
2015          * but the read-ahead I/O as well i.e. completely pointless.
2016          *
2017          * Read-ahead will be disabled because @c->bdi.ra_pages is 0.
2018          */
2019         c->bdi.name = "ubifs",
2020         c->bdi.capabilities = BDI_CAP_MAP_COPY;
2021         err  = bdi_init(&c->bdi);
2022         if (err)
2023                 goto out_close;
2024         err = bdi_register(&c->bdi, NULL, "ubifs_%d_%d",
2025                            c->vi.ubi_num, c->vi.vol_id);
2026         if (err)
2027                 goto out_bdi;
2028 
2029         err = ubifs_parse_options(c, data, 0);
2030         if (err)
2031                 goto out_bdi;
2032 
2033         sb->s_bdi = &c->bdi;
2034         sb->s_fs_info = c;
2035         sb->s_magic = UBIFS_SUPER_MAGIC;
2036         sb->s_blocksize = UBIFS_BLOCK_SIZE;
2037         sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
2038         sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
2039         if (c->max_inode_sz > MAX_LFS_FILESIZE)
2040                 sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
2041         sb->s_op = &ubifs_super_operations;
2042 
2043         mutex_lock(&c->umount_mutex);
2044         err = mount_ubifs(c);
2045         if (err) {
2046                 ubifs_assert(err < 0);
2047                 goto out_unlock;
2048         }
2049 
2050         /* Read the root inode */
2051         root = ubifs_iget(sb, UBIFS_ROOT_INO);
2052         if (IS_ERR(root)) {
2053                 err = PTR_ERR(root);
2054                 goto out_umount;
2055         }
2056 
2057         sb->s_root = d_make_root(root);
2058         if (!sb->s_root) {
2059                 err = -ENOMEM;
2060                 goto out_umount;
2061         }
2062 
2063         mutex_unlock(&c->umount_mutex);
2064         return 0;
2065 
2066 out_umount:
2067         ubifs_umount(c);
2068 out_unlock:
2069         mutex_unlock(&c->umount_mutex);
2070 out_bdi:
2071         bdi_destroy(&c->bdi);
2072 out_close:
2073         ubi_close_volume(c->ubi);
2074 out:
2075         return err;
2076 }
2077 
2078 static int sb_test(struct super_block *sb, void *data)
2079 {
2080         struct ubifs_info *c1 = data;
2081         struct ubifs_info *c = sb->s_fs_info;
2082 
2083         return c->vi.cdev == c1->vi.cdev;
2084 }
2085 
2086 static int sb_set(struct super_block *sb, void *data)
2087 {
2088         sb->s_fs_info = data;
2089         return set_anon_super(sb, NULL);
2090 }
2091 
2092 static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
2093                         const char *name, void *data)
2094 {
2095         struct ubi_volume_desc *ubi;
2096         struct ubifs_info *c;
2097         struct super_block *sb;
2098         int err;
2099 
2100         dbg_gen("name %s, flags %#x", name, flags);
2101 
2102         /*
2103          * Get UBI device number and volume ID. Mount it read-only so far
2104          * because this might be a new mount point, and UBI allows only one
2105          * read-write user at a time.
2106          */
2107         ubi = open_ubi(name, UBI_READONLY);
2108         if (IS_ERR(ubi)) {
2109                 ubifs_err("cannot open \"%s\", error %d",
2110                           name, (int)PTR_ERR(ubi));
2111                 return ERR_CAST(ubi);
2112         }
2113 
2114         c = alloc_ubifs_info(ubi);
2115         if (!c) {
2116                 err = -ENOMEM;
2117                 goto out_close;
2118         }
2119 
2120         dbg_gen("opened ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
2121 
2122         sb = sget(fs_type, sb_test, sb_set, flags, c);
2123         if (IS_ERR(sb)) {
2124                 err = PTR_ERR(sb);
2125                 kfree(c);
2126                 goto out_close;
2127         }
2128 
2129         if (sb->s_root) {
2130                 struct ubifs_info *c1 = sb->s_fs_info;
2131                 kfree(c);
2132                 /* A new mount point for already mounted UBIFS */
2133                 dbg_gen("this ubi volume is already mounted");
2134                 if (!!(flags & MS_RDONLY) != c1->ro_mount) {
2135                         err = -EBUSY;
2136                         goto out_deact;
2137                 }
2138         } else {
2139                 err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
2140                 if (err)
2141                         goto out_deact;
2142                 /* We do not support atime */
2143                 sb->s_flags |= MS_ACTIVE | MS_NOATIME;
2144         }
2145 
2146         /* 'fill_super()' opens ubi again so we must close it here */
2147         ubi_close_volume(ubi);
2148 
2149         return dget(sb->s_root);
2150 
2151 out_deact:
2152         deactivate_locked_super(sb);
2153 out_close:
2154         ubi_close_volume(ubi);
2155         return ERR_PTR(err);
2156 }
2157 
2158 static void kill_ubifs_super(struct super_block *s)
2159 {
2160         struct ubifs_info *c = s->s_fs_info;
2161         kill_anon_super(s);
2162         kfree(c);
2163 }
2164 
2165 static struct file_system_type ubifs_fs_type = {
2166         .name    = "ubifs",
2167         .owner   = THIS_MODULE,
2168         .mount   = ubifs_mount,
2169         .kill_sb = kill_ubifs_super,
2170 };
2171 MODULE_ALIAS_FS("ubifs");
2172 
2173 /*
2174  * Inode slab cache constructor.
2175  */
2176 static void inode_slab_ctor(void *obj)
2177 {
2178         struct ubifs_inode *ui = obj;
2179         inode_init_once(&ui->vfs_inode);
2180 }
2181 
2182 static int __init ubifs_init(void)
2183 {
2184         int err;
2185 
2186         BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);
2187 
2188         /* Make sure node sizes are 8-byte aligned */
2189         BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
2190         BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
2191         BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
2192         BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
2193         BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
2194         BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
2195         BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
2196         BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
2197         BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
2198         BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
2199         BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);
2200 
2201         BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
2202         BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
2203         BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
2204         BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
2205         BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
2206         BUILD_BUG_ON(MIN_WRITE_SZ           & 7);
2207 
2208         /* Check min. node size */
2209         BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
2210         BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
2211         BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
2212         BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);
2213 
2214         BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2215         BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2216         BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
2217         BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);
2218 
2219         /* Defined node sizes */
2220         BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
2221         BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
2222         BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
2223         BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
2224 
2225         /*
2226          * We use 2 bit wide bit-fields to store compression type, which should
2227          * be amended if more compressors are added. The bit-fields are:
2228          * @compr_type in 'struct ubifs_inode', @default_compr in
2229          * 'struct ubifs_info' and @compr_type in 'struct ubifs_mount_opts'.
2230          */
2231         BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);
2232 
2233         /*
2234          * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
2235          * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
2236          */
2237         if (PAGE_CACHE_SIZE < UBIFS_BLOCK_SIZE) {
2238                 ubifs_err("VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
2239                           (unsigned int)PAGE_CACHE_SIZE);
2240                 return -EINVAL;
2241         }
2242 
2243         ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
2244                                 sizeof(struct ubifs_inode), 0,
2245                                 SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT,
2246                                 &inode_slab_ctor);
2247         if (!ubifs_inode_slab)
2248                 return -ENOMEM;
2249 
2250         register_shrinker(&ubifs_shrinker_info);
2251 
2252         err = ubifs_compressors_init();
2253         if (err)
2254                 goto out_shrinker;
2255 
2256         err = dbg_debugfs_init();
2257         if (err)
2258                 goto out_compr;
2259 
2260         err = register_filesystem(&ubifs_fs_type);
2261         if (err) {
2262                 ubifs_err("cannot register file system, error %d", err);
2263                 goto out_dbg;
2264         }
2265         return 0;
2266 
2267 out_dbg:
2268         dbg_debugfs_exit();
2269 out_compr:
2270         ubifs_compressors_exit();
2271 out_shrinker:
2272         unregister_shrinker(&ubifs_shrinker_info);
2273         kmem_cache_destroy(ubifs_inode_slab);
2274         return err;
2275 }
2276 /* late_initcall to let compressors initialize first */
2277 late_initcall(ubifs_init);
2278 
2279 static void __exit ubifs_exit(void)
2280 {
2281         ubifs_assert(list_empty(&ubifs_infos));
2282         ubifs_assert(atomic_long_read(&ubifs_clean_zn_cnt) == 0);
2283 
2284         dbg_debugfs_exit();
2285         ubifs_compressors_exit();
2286         unregister_shrinker(&ubifs_shrinker_info);
2287 
2288         /*
2289          * Make sure all delayed rcu free inodes are flushed before we
2290          * destroy cache.
2291          */
2292         rcu_barrier();
2293         kmem_cache_destroy(ubifs_inode_slab);
2294         unregister_filesystem(&ubifs_fs_type);
2295 }
2296 module_exit(ubifs_exit);
2297 
2298 MODULE_LICENSE("GPL");
2299 MODULE_VERSION(__stringify(UBIFS_VERSION));
2300 MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
2301 MODULE_DESCRIPTION("UBIFS - UBI File System");
2302 

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