Version:  2.0.40 2.2.26 2.4.37 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5

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

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