Version:  2.0.40 2.2.26 2.4.37 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 3.19 4.0 4.1

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

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