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

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  1 /*
  2  * This file is part of UBIFS.
  3  *
  4  * Copyright (C) 2006-2008 Nokia Corporation.
  5  *
  6  * This program is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 as published by
  8  * the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 13  * more details.
 14  *
 15  * You should have received a copy of the GNU General Public License along with
 16  * this program; if not, write to the Free Software Foundation, Inc., 51
 17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 18  *
 19  * Authors: Artem Bityutskiy (Битюцкий Артём)
 20  *          Adrian Hunter
 21  */
 22 
 23 /*
 24  * This file implements UBIFS initialization and VFS superblock operations. Some
 25  * initialization stuff which is rather large and complex is placed at
 26  * corresponding subsystems, but most of it is here.
 27  */
 28 
 29 #include <linux/init.h>
 30 #include <linux/slab.h>
 31 #include <linux/module.h>
 32 #include <linux/ctype.h>
 33 #include <linux/kthread.h>
 34 #include <linux/parser.h>
 35 #include <linux/seq_file.h>
 36 #include <linux/mount.h>
 37 #include <linux/math64.h>
 38 #include <linux/writeback.h>
 39 #include "ubifs.h"
 40 
 41 /*
 42  * Maximum amount of memory we may 'kmalloc()' without worrying that we are
 43  * allocating too much.
 44  */
 45 #define UBIFS_KMALLOC_OK (128*1024)
 46 
 47 /* Slab cache for UBIFS inodes */
 48 struct kmem_cache *ubifs_inode_slab;
 49 
 50 /* UBIFS TNC shrinker description */
 51 static struct shrinker ubifs_shrinker_info = {
 52         .shrink = ubifs_shrinker,
 53         .seeks = DEFAULT_SEEKS,
 54 };
 55 
 56 /**
 57  * validate_inode - validate inode.
 58  * @c: UBIFS file-system description object
 59  * @inode: the inode to validate
 60  *
 61  * This is a helper function for 'ubifs_iget()' which validates various fields
 62  * of a newly built inode to make sure they contain sane values and prevent
 63  * possible vulnerabilities. Returns zero if the inode is all right and
 64  * a non-zero error code if not.
 65  */
 66 static int validate_inode(struct ubifs_info *c, const struct inode *inode)
 67 {
 68         int err;
 69         const struct ubifs_inode *ui = ubifs_inode(inode);
 70 
 71         if (inode->i_size > c->max_inode_sz) {
 72                 ubifs_err("inode is too large (%lld)",
 73                           (long long)inode->i_size);
 74                 return 1;
 75         }
 76 
 77         if (ui->compr_type < 0 || ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
 78                 ubifs_err("unknown compression type %d", ui->compr_type);
 79                 return 2;
 80         }
 81 
 82         if (ui->xattr_names + ui->xattr_cnt > XATTR_LIST_MAX)
 83                 return 3;
 84 
 85         if (ui->data_len < 0 || ui->data_len > UBIFS_MAX_INO_DATA)
 86                 return 4;
 87 
 88         if (ui->xattr && !S_ISREG(inode->i_mode))
 89                 return 5;
 90 
 91         if (!ubifs_compr_present(ui->compr_type)) {
 92                 ubifs_warn("inode %lu uses '%s' compression, but it was not compiled in",
 93                            inode->i_ino, ubifs_compr_name(ui->compr_type));
 94         }
 95 
 96         err = dbg_check_dir(c, inode);
 97         return err;
 98 }
 99 
100 struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
101 {
102         int err;
103         union ubifs_key key;
104         struct ubifs_ino_node *ino;
105         struct ubifs_info *c = sb->s_fs_info;
106         struct inode *inode;
107         struct ubifs_inode *ui;
108 
109         dbg_gen("inode %lu", inum);
110 
111         inode = iget_locked(sb, inum);
112         if (!inode)
113                 return ERR_PTR(-ENOMEM);
114         if (!(inode->i_state & I_NEW))
115                 return inode;
116         ui = ubifs_inode(inode);
117 
118         ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
119         if (!ino) {
120                 err = -ENOMEM;
121                 goto out;
122         }
123 
124         ino_key_init(c, &key, inode->i_ino);
125 
126         err = ubifs_tnc_lookup(c, &key, ino);
127         if (err)
128                 goto out_ino;
129 
130         inode->i_flags |= (S_NOCMTIME | S_NOATIME);
131         set_nlink(inode, le32_to_cpu(ino->nlink));
132         i_uid_write(inode, le32_to_cpu(ino->uid));
133         i_gid_write(inode, le32_to_cpu(ino->gid));
134         inode->i_atime.tv_sec  = (int64_t)le64_to_cpu(ino->atime_sec);
135         inode->i_atime.tv_nsec = le32_to_cpu(ino->atime_nsec);
136         inode->i_mtime.tv_sec  = (int64_t)le64_to_cpu(ino->mtime_sec);
137         inode->i_mtime.tv_nsec = le32_to_cpu(ino->mtime_nsec);
138         inode->i_ctime.tv_sec  = (int64_t)le64_to_cpu(ino->ctime_sec);
139         inode->i_ctime.tv_nsec = le32_to_cpu(ino->ctime_nsec);
140         inode->i_mode = le32_to_cpu(ino->mode);
141         inode->i_size = le64_to_cpu(ino->size);
142 
143         ui->data_len    = le32_to_cpu(ino->data_len);
144         ui->flags       = le32_to_cpu(ino->flags);
145         ui->compr_type  = le16_to_cpu(ino->compr_type);
146         ui->creat_sqnum = le64_to_cpu(ino->creat_sqnum);
147         ui->xattr_cnt   = le32_to_cpu(ino->xattr_cnt);
148         ui->xattr_size  = le32_to_cpu(ino->xattr_size);
149         ui->xattr_names = le32_to_cpu(ino->xattr_names);
150         ui->synced_i_size = ui->ui_size = inode->i_size;
151 
152         ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;
153 
154         err = validate_inode(c, inode);
155         if (err)
156                 goto out_invalid;
157 
158         /* Disable read-ahead */
159         inode->i_mapping->backing_dev_info = &c->bdi;
160 
161         switch (inode->i_mode & S_IFMT) {
162         case S_IFREG:
163                 inode->i_mapping->a_ops = &ubifs_file_address_operations;
164                 inode->i_op = &ubifs_file_inode_operations;
165                 inode->i_fop = &ubifs_file_operations;
166                 if (ui->xattr) {
167                         ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
168                         if (!ui->data) {
169                                 err = -ENOMEM;
170                                 goto out_ino;
171                         }
172                         memcpy(ui->data, ino->data, ui->data_len);
173                         ((char *)ui->data)[ui->data_len] = '\0';
174                 } else if (ui->data_len != 0) {
175                         err = 10;
176                         goto out_invalid;
177                 }
178                 break;
179         case S_IFDIR:
180                 inode->i_op  = &ubifs_dir_inode_operations;
181                 inode->i_fop = &ubifs_dir_operations;
182                 if (ui->data_len != 0) {
183                         err = 11;
184                         goto out_invalid;
185                 }
186                 break;
187         case S_IFLNK:
188                 inode->i_op = &ubifs_symlink_inode_operations;
189                 if (ui->data_len <= 0 || ui->data_len > UBIFS_MAX_INO_DATA) {
190                         err = 12;
191                         goto out_invalid;
192                 }
193                 ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
194                 if (!ui->data) {
195                         err = -ENOMEM;
196                         goto out_ino;
197                 }
198                 memcpy(ui->data, ino->data, ui->data_len);
199                 ((char *)ui->data)[ui->data_len] = '\0';
200                 break;
201         case S_IFBLK:
202         case S_IFCHR:
203         {
204                 dev_t rdev;
205                 union ubifs_dev_desc *dev;
206 
207                 ui->data = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
208                 if (!ui->data) {
209                         err = -ENOMEM;
210                         goto out_ino;
211                 }
212 
213                 dev = (union ubifs_dev_desc *)ino->data;
214                 if (ui->data_len == sizeof(dev->new))
215                         rdev = new_decode_dev(le32_to_cpu(dev->new));
216                 else if (ui->data_len == sizeof(dev->huge))
217                         rdev = huge_decode_dev(le64_to_cpu(dev->huge));
218                 else {
219                         err = 13;
220                         goto out_invalid;
221                 }
222                 memcpy(ui->data, ino->data, ui->data_len);
223                 inode->i_op = &ubifs_file_inode_operations;
224                 init_special_inode(inode, inode->i_mode, rdev);
225                 break;
226         }
227         case S_IFSOCK:
228         case S_IFIFO:
229                 inode->i_op = &ubifs_file_inode_operations;
230                 init_special_inode(inode, inode->i_mode, 0);
231                 if (ui->data_len != 0) {
232                         err = 14;
233                         goto out_invalid;
234                 }
235                 break;
236         default:
237                 err = 15;
238                 goto out_invalid;
239         }
240 
241         kfree(ino);
242         ubifs_set_inode_flags(inode);
243         unlock_new_inode(inode);
244         return inode;
245 
246 out_invalid:
247         ubifs_err("inode %lu validation failed, error %d", inode->i_ino, err);
248         ubifs_dump_node(c, ino);
249         ubifs_dump_inode(c, inode);
250         err = -EINVAL;
251 out_ino:
252         kfree(ino);
253 out:
254         ubifs_err("failed to read inode %lu, error %d", inode->i_ino, err);
255         iget_failed(inode);
256         return ERR_PTR(err);
257 }
258 
259 static struct inode *ubifs_alloc_inode(struct super_block *sb)
260 {
261         struct ubifs_inode *ui;
262 
263         ui = kmem_cache_alloc(ubifs_inode_slab, GFP_NOFS);
264         if (!ui)
265                 return NULL;
266 
267         memset((void *)ui + sizeof(struct inode), 0,
268                sizeof(struct ubifs_inode) - sizeof(struct inode));
269         mutex_init(&ui->ui_mutex);
270         spin_lock_init(&ui->ui_lock);
271         return &ui->vfs_inode;
272 };
273 
274 static void ubifs_i_callback(struct rcu_head *head)
275 {
276         struct inode *inode = container_of(head, struct inode, i_rcu);
277         struct ubifs_inode *ui = ubifs_inode(inode);
278         kmem_cache_free(ubifs_inode_slab, ui);
279 }
280 
281 static void ubifs_destroy_inode(struct inode *inode)
282 {
283         struct ubifs_inode *ui = ubifs_inode(inode);
284 
285         kfree(ui->data);
286         call_rcu(&inode->i_rcu, ubifs_i_callback);
287 }
288 
289 /*
290  * Note, Linux write-back code calls this without 'i_mutex'.
291  */
292 static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
293 {
294         int err = 0;
295         struct ubifs_info *c = inode->i_sb->s_fs_info;
296         struct ubifs_inode *ui = ubifs_inode(inode);
297 
298         ubifs_assert(!ui->xattr);
299         if (is_bad_inode(inode))
300                 return 0;
301 
302         mutex_lock(&ui->ui_mutex);
303         /*
304          * Due to races between write-back forced by budgeting
305          * (see 'sync_some_inodes()') and background write-back, the inode may
306          * have already been synchronized, do not do this again. This might
307          * also happen if it was synchronized in an VFS operation, e.g.
308          * 'ubifs_link()'.
309          */
310         if (!ui->dirty) {
311                 mutex_unlock(&ui->ui_mutex);
312                 return 0;
313         }
314 
315         /*
316          * As an optimization, do not write orphan inodes to the media just
317          * because this is not needed.
318          */
319         dbg_gen("inode %lu, mode %#x, nlink %u",
320                 inode->i_ino, (int)inode->i_mode, inode->i_nlink);
321         if (inode->i_nlink) {
322                 err = ubifs_jnl_write_inode(c, inode);
323                 if (err)
324                         ubifs_err("can't write inode %lu, error %d",
325                                   inode->i_ino, err);
326                 else
327                         err = dbg_check_inode_size(c, inode, ui->ui_size);
328         }
329 
330         ui->dirty = 0;
331         mutex_unlock(&ui->ui_mutex);
332         ubifs_release_dirty_inode_budget(c, ui);
333         return err;
334 }
335 
336 static void ubifs_evict_inode(struct inode *inode)
337 {
338         int err;
339         struct ubifs_info *c = inode->i_sb->s_fs_info;
340         struct ubifs_inode *ui = ubifs_inode(inode);
341 
342         if (ui->xattr)
343                 /*
344                  * Extended attribute inode deletions are fully handled in
345                  * 'ubifs_removexattr()'. These inodes are special and have
346                  * limited usage, so there is nothing to do here.
347                  */
348                 goto out;
349 
350         dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
351         ubifs_assert(!atomic_read(&inode->i_count));
352 
353         truncate_inode_pages(&inode->i_data, 0);
354 
355         if (inode->i_nlink)
356                 goto done;
357 
358         if (is_bad_inode(inode))
359                 goto out;
360 
361         ui->ui_size = inode->i_size = 0;
362         err = ubifs_jnl_delete_inode(c, inode);
363         if (err)
364                 /*
365                  * Worst case we have a lost orphan inode wasting space, so a
366                  * simple error message is OK here.
367                  */
368                 ubifs_err("can't delete inode %lu, error %d",
369                           inode->i_ino, err);
370 
371 out:
372         if (ui->dirty)
373                 ubifs_release_dirty_inode_budget(c, ui);
374         else {
375                 /* We've deleted something - clean the "no space" flags */
376                 c->bi.nospace = c->bi.nospace_rp = 0;
377                 smp_wmb();
378         }
379 done:
380         clear_inode(inode);
381 }
382 
383 static void ubifs_dirty_inode(struct inode *inode, int flags)
384 {
385         struct ubifs_inode *ui = ubifs_inode(inode);
386 
387         ubifs_assert(mutex_is_locked(&ui->ui_mutex));
388         if (!ui->dirty) {
389                 ui->dirty = 1;
390                 dbg_gen("inode %lu",  inode->i_ino);
391         }
392 }
393 
394 static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
395 {
396         struct ubifs_info *c = dentry->d_sb->s_fs_info;
397         unsigned long long free;
398         __le32 *uuid = (__le32 *)c->uuid;
399 
400         free = ubifs_get_free_space(c);
401         dbg_gen("free space %lld bytes (%lld blocks)",
402                 free, free >> UBIFS_BLOCK_SHIFT);
403 
404         buf->f_type = UBIFS_SUPER_MAGIC;
405         buf->f_bsize = UBIFS_BLOCK_SIZE;
406         buf->f_blocks = c->block_cnt;
407         buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
408         if (free > c->report_rp_size)
409                 buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
410         else
411                 buf->f_bavail = 0;
412         buf->f_files = 0;
413         buf->f_ffree = 0;
414         buf->f_namelen = UBIFS_MAX_NLEN;
415         buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
416         buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
417         ubifs_assert(buf->f_bfree <= c->block_cnt);
418         return 0;
419 }
420 
421 static int ubifs_show_options(struct seq_file *s, struct dentry *root)
422 {
423         struct ubifs_info *c = root->d_sb->s_fs_info;
424 
425         if (c->mount_opts.unmount_mode == 2)
426                 seq_printf(s, ",fast_unmount");
427         else if (c->mount_opts.unmount_mode == 1)
428                 seq_printf(s, ",norm_unmount");
429 
430         if (c->mount_opts.bulk_read == 2)
431                 seq_printf(s, ",bulk_read");
432         else if (c->mount_opts.bulk_read == 1)
433                 seq_printf(s, ",no_bulk_read");
434 
435         if (c->mount_opts.chk_data_crc == 2)
436                 seq_printf(s, ",chk_data_crc");
437         else if (c->mount_opts.chk_data_crc == 1)
438                 seq_printf(s, ",no_chk_data_crc");
439 
440         if (c->mount_opts.override_compr) {
441                 seq_printf(s, ",compr=%s",
442                            ubifs_compr_name(c->mount_opts.compr_type));
443         }
444 
445         return 0;
446 }
447 
448 static int ubifs_sync_fs(struct super_block *sb, int wait)
449 {
450         int i, err;
451         struct ubifs_info *c = sb->s_fs_info;
452 
453         /*
454          * Zero @wait is just an advisory thing to help the file system shove
455          * lots of data into the queues, and there will be the second
456          * '->sync_fs()' call, with non-zero @wait.
457          */
458         if (!wait)
459                 return 0;
460 
461         /*
462          * Synchronize write buffers, because 'ubifs_run_commit()' does not
463          * do this if it waits for an already running commit.
464          */
465         for (i = 0; i < c->jhead_cnt; i++) {
466                 err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
467                 if (err)
468                         return err;
469         }
470 
471         /*
472          * Strictly speaking, it is not necessary to commit the journal here,
473          * synchronizing write-buffers would be enough. But committing makes
474          * UBIFS free space predictions much more accurate, so we want to let
475          * the user be able to get more accurate results of 'statfs()' after
476          * they synchronize the file system.
477          */
478         err = ubifs_run_commit(c);
479         if (err)
480                 return err;
481 
482         return ubi_sync(c->vi.ubi_num);
483 }
484 
485 /**
486  * init_constants_early - initialize UBIFS constants.
487  * @c: UBIFS file-system description object
488  *
489  * This function initialize UBIFS constants which do not need the superblock to
490  * be read. It also checks that the UBI volume satisfies basic UBIFS
491  * requirements. Returns zero in case of success and a negative error code in
492  * case of failure.
493  */
494 static int init_constants_early(struct ubifs_info *c)
495 {
496         if (c->vi.corrupted) {
497                 ubifs_warn("UBI volume is corrupted - read-only mode");
498                 c->ro_media = 1;
499         }
500 
501         if (c->di.ro_mode) {
502                 ubifs_msg("read-only UBI device");
503                 c->ro_media = 1;
504         }
505 
506         if (c->vi.vol_type == UBI_STATIC_VOLUME) {
507                 ubifs_msg("static UBI volume - read-only mode");
508                 c->ro_media = 1;
509         }
510 
511         c->leb_cnt = c->vi.size;
512         c->leb_size = c->vi.usable_leb_size;
513         c->leb_start = c->di.leb_start;
514         c->half_leb_size = c->leb_size / 2;
515         c->min_io_size = c->di.min_io_size;
516         c->min_io_shift = fls(c->min_io_size) - 1;
517         c->max_write_size = c->di.max_write_size;
518         c->max_write_shift = fls(c->max_write_size) - 1;
519 
520         if (c->leb_size < UBIFS_MIN_LEB_SZ) {
521                 ubifs_err("too small LEBs (%d bytes), min. is %d bytes",
522                           c->leb_size, UBIFS_MIN_LEB_SZ);
523                 return -EINVAL;
524         }
525 
526         if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
527                 ubifs_err("too few LEBs (%d), min. is %d",
528                           c->leb_cnt, UBIFS_MIN_LEB_CNT);
529                 return -EINVAL;
530         }
531 
532         if (!is_power_of_2(c->min_io_size)) {
533                 ubifs_err("bad min. I/O size %d", c->min_io_size);
534                 return -EINVAL;
535         }
536 
537         /*
538          * Maximum write size has to be greater or equivalent to min. I/O
539          * size, and be multiple of min. I/O size.
540          */
541         if (c->max_write_size < c->min_io_size ||
542             c->max_write_size % c->min_io_size ||
543             !is_power_of_2(c->max_write_size)) {
544                 ubifs_err("bad write buffer size %d for %d min. I/O unit",
545                           c->max_write_size, c->min_io_size);
546                 return -EINVAL;
547         }
548 
549         /*
550          * UBIFS aligns all node to 8-byte boundary, so to make function in
551          * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
552          * less than 8.
553          */
554         if (c->min_io_size < 8) {
555                 c->min_io_size = 8;
556                 c->min_io_shift = 3;
557                 if (c->max_write_size < c->min_io_size) {
558                         c->max_write_size = c->min_io_size;
559                         c->max_write_shift = c->min_io_shift;
560                 }
561         }
562 
563         c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
564         c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);
565 
566         /*
567          * Initialize node length ranges which are mostly needed for node
568          * length validation.
569          */
570         c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
571         c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
572         c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
573         c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
574         c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
575         c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;
576 
577         c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
578         c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
579         c->ranges[UBIFS_ORPH_NODE].min_len =
580                                 UBIFS_ORPH_NODE_SZ + sizeof(__le64);
581         c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
582         c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
583         c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
584         c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
585         c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
586         c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
587         c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
588         /*
589          * Minimum indexing node size is amended later when superblock is
590          * read and the key length is known.
591          */
592         c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
593         /*
594          * Maximum indexing node size is amended later when superblock is
595          * read and the fanout is known.
596          */
597         c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
598 
599         /*
600          * Initialize dead and dark LEB space watermarks. See gc.c for comments
601          * about these values.
602          */
603         c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
604         c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
605 
606         /*
607          * Calculate how many bytes would be wasted at the end of LEB if it was
608          * fully filled with data nodes of maximum size. This is used in
609          * calculations when reporting free space.
610          */
611         c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
612 
613         /* Buffer size for bulk-reads */
614         c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
615         if (c->max_bu_buf_len > c->leb_size)
616                 c->max_bu_buf_len = c->leb_size;
617         return 0;
618 }
619 
620 /**
621  * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
622  * @c: UBIFS file-system description object
623  * @lnum: LEB the write-buffer was synchronized to
624  * @free: how many free bytes left in this LEB
625  * @pad: how many bytes were padded
626  *
627  * This is a callback function which is called by the I/O unit when the
628  * write-buffer is synchronized. We need this to correctly maintain space
629  * accounting in bud logical eraseblocks. This function returns zero in case of
630  * success and a negative error code in case of failure.
631  *
632  * This function actually belongs to the journal, but we keep it here because
633  * we want to keep it static.
634  */
635 static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
636 {
637         return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
638 }
639 
640 /*
641  * init_constants_sb - initialize UBIFS constants.
642  * @c: UBIFS file-system description object
643  *
644  * This is a helper function which initializes various UBIFS constants after
645  * the superblock has been read. It also checks various UBIFS parameters and
646  * makes sure they are all right. Returns zero in case of success and a
647  * negative error code in case of failure.
648  */
649 static int init_constants_sb(struct ubifs_info *c)
650 {
651         int tmp, err;
652         long long tmp64;
653 
654         c->main_bytes = (long long)c->main_lebs * c->leb_size;
655         c->max_znode_sz = sizeof(struct ubifs_znode) +
656                                 c->fanout * sizeof(struct ubifs_zbranch);
657 
658         tmp = ubifs_idx_node_sz(c, 1);
659         c->ranges[UBIFS_IDX_NODE].min_len = tmp;
660         c->min_idx_node_sz = ALIGN(tmp, 8);
661 
662         tmp = ubifs_idx_node_sz(c, c->fanout);
663         c->ranges[UBIFS_IDX_NODE].max_len = tmp;
664         c->max_idx_node_sz = ALIGN(tmp, 8);
665 
666         /* Make sure LEB size is large enough to fit full commit */
667         tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
668         tmp = ALIGN(tmp, c->min_io_size);
669         if (tmp > c->leb_size) {
670                 ubifs_err("too small LEB size %d, at least %d needed",
671                           c->leb_size, tmp);
672                 return -EINVAL;
673         }
674 
675         /*
676          * Make sure that the log is large enough to fit reference nodes for
677          * all buds plus one reserved LEB.
678          */
679         tmp64 = c->max_bud_bytes + c->leb_size - 1;
680         c->max_bud_cnt = div_u64(tmp64, c->leb_size);
681         tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
682         tmp /= c->leb_size;
683         tmp += 1;
684         if (c->log_lebs < tmp) {
685                 ubifs_err("too small log %d LEBs, required min. %d LEBs",
686                           c->log_lebs, tmp);
687                 return -EINVAL;
688         }
689 
690         /*
691          * When budgeting we assume worst-case scenarios when the pages are not
692          * be compressed and direntries are of the maximum size.
693          *
694          * Note, data, which may be stored in inodes is budgeted separately, so
695          * it is not included into 'c->bi.inode_budget'.
696          */
697         c->bi.page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
698         c->bi.inode_budget = UBIFS_INO_NODE_SZ;
699         c->bi.dent_budget = UBIFS_MAX_DENT_NODE_SZ;
700 
701         /*
702          * When the amount of flash space used by buds becomes
703          * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
704          * The writers are unblocked when the commit is finished. To avoid
705          * writers to be blocked UBIFS initiates background commit in advance,
706          * when number of bud bytes becomes above the limit defined below.
707          */
708         c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;
709 
710         /*
711          * Ensure minimum journal size. All the bytes in the journal heads are
712          * considered to be used, when calculating the current journal usage.
713          * Consequently, if the journal is too small, UBIFS will treat it as
714          * always full.
715          */
716         tmp64 = (long long)(c->jhead_cnt + 1) * c->leb_size + 1;
717         if (c->bg_bud_bytes < tmp64)
718                 c->bg_bud_bytes = tmp64;
719         if (c->max_bud_bytes < tmp64 + c->leb_size)
720                 c->max_bud_bytes = tmp64 + c->leb_size;
721 
722         err = ubifs_calc_lpt_geom(c);
723         if (err)
724                 return err;
725 
726         /* Initialize effective LEB size used in budgeting calculations */
727         c->idx_leb_size = c->leb_size - c->max_idx_node_sz;
728         return 0;
729 }
730 
731 /*
732  * init_constants_master - initialize UBIFS constants.
733  * @c: UBIFS file-system description object
734  *
735  * This is a helper function which initializes various UBIFS constants after
736  * the master node has been read. It also checks various UBIFS parameters and
737  * makes sure they are all right.
738  */
739 static void init_constants_master(struct ubifs_info *c)
740 {
741         long long tmp64;
742 
743         c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
744         c->report_rp_size = ubifs_reported_space(c, c->rp_size);
745 
746         /*
747          * Calculate total amount of FS blocks. This number is not used
748          * internally because it does not make much sense for UBIFS, but it is
749          * necessary to report something for the 'statfs()' call.
750          *
751          * Subtract the LEB reserved for GC, the LEB which is reserved for
752          * deletions, minimum LEBs for the index, and assume only one journal
753          * head is available.
754          */
755         tmp64 = c->main_lebs - 1 - 1 - MIN_INDEX_LEBS - c->jhead_cnt + 1;
756         tmp64 *= (long long)c->leb_size - c->leb_overhead;
757         tmp64 = ubifs_reported_space(c, tmp64);
758         c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
759 }
760 
761 /**
762  * take_gc_lnum - reserve GC LEB.
763  * @c: UBIFS file-system description object
764  *
765  * This function ensures that the LEB reserved for garbage collection is marked
766  * as "taken" in lprops. We also have to set free space to LEB size and dirty
767  * space to zero, because lprops may contain out-of-date information if the
768  * file-system was un-mounted before it has been committed. This function
769  * returns zero in case of success and a negative error code in case of
770  * failure.
771  */
772 static int take_gc_lnum(struct ubifs_info *c)
773 {
774         int err;
775 
776         if (c->gc_lnum == -1) {
777                 ubifs_err("no LEB for GC");
778                 return -EINVAL;
779         }
780 
781         /* And we have to tell lprops that this LEB is taken */
782         err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
783                                   LPROPS_TAKEN, 0, 0);
784         return err;
785 }
786 
787 /**
788  * alloc_wbufs - allocate write-buffers.
789  * @c: UBIFS file-system description object
790  *
791  * This helper function allocates and initializes UBIFS write-buffers. Returns
792  * zero in case of success and %-ENOMEM in case of failure.
793  */
794 static int alloc_wbufs(struct ubifs_info *c)
795 {
796         int i, err;
797 
798         c->jheads = kzalloc(c->jhead_cnt * sizeof(struct ubifs_jhead),
799                            GFP_KERNEL);
800         if (!c->jheads)
801                 return -ENOMEM;
802 
803         /* Initialize journal heads */
804         for (i = 0; i < c->jhead_cnt; i++) {
805                 INIT_LIST_HEAD(&c->jheads[i].buds_list);
806                 err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
807                 if (err)
808                         return err;
809 
810                 c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
811                 c->jheads[i].wbuf.jhead = i;
812                 c->jheads[i].grouped = 1;
813         }
814 
815         /*
816          * Garbage Collector head does not need to be synchronized by timer.
817          * Also GC head nodes are not grouped.
818          */
819         c->jheads[GCHD].wbuf.no_timer = 1;
820         c->jheads[GCHD].grouped = 0;
821 
822         return 0;
823 }
824 
825 /**
826  * free_wbufs - free write-buffers.
827  * @c: UBIFS file-system description object
828  */
829 static void free_wbufs(struct ubifs_info *c)
830 {
831         int i;
832 
833         if (c->jheads) {
834                 for (i = 0; i < c->jhead_cnt; i++) {
835                         kfree(c->jheads[i].wbuf.buf);
836                         kfree(c->jheads[i].wbuf.inodes);
837                 }
838                 kfree(c->jheads);
839                 c->jheads = NULL;
840         }
841 }
842 
843 /**
844  * free_orphans - free orphans.
845  * @c: UBIFS file-system description object
846  */
847 static void free_orphans(struct ubifs_info *c)
848 {
849         struct ubifs_orphan *orph;
850 
851         while (c->orph_dnext) {
852                 orph = c->orph_dnext;
853                 c->orph_dnext = orph->dnext;
854                 list_del(&orph->list);
855                 kfree(orph);
856         }
857 
858         while (!list_empty(&c->orph_list)) {
859                 orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
860                 list_del(&orph->list);
861                 kfree(orph);
862                 ubifs_err("orphan list not empty at unmount");
863         }
864 
865         vfree(c->orph_buf);
866         c->orph_buf = NULL;
867 }
868 
869 /**
870  * free_buds - free per-bud objects.
871  * @c: UBIFS file-system description object
872  */
873 static void free_buds(struct ubifs_info *c)
874 {
875         struct rb_node *this = c->buds.rb_node;
876         struct ubifs_bud *bud;
877 
878         while (this) {
879                 if (this->rb_left)
880                         this = this->rb_left;
881                 else if (this->rb_right)
882                         this = this->rb_right;
883                 else {
884                         bud = rb_entry(this, struct ubifs_bud, rb);
885                         this = rb_parent(this);
886                         if (this) {
887                                 if (this->rb_left == &bud->rb)
888                                         this->rb_left = NULL;
889                                 else
890                                         this->rb_right = NULL;
891                         }
892                         kfree(bud);
893                 }
894         }
895 }
896 
897 /**
898  * check_volume_empty - check if the UBI volume is empty.
899  * @c: UBIFS file-system description object
900  *
901  * This function checks if the UBIFS volume is empty by looking if its LEBs are
902  * mapped or not. The result of checking is stored in the @c->empty variable.
903  * Returns zero in case of success and a negative error code in case of
904  * failure.
905  */
906 static int check_volume_empty(struct ubifs_info *c)
907 {
908         int lnum, err;
909 
910         c->empty = 1;
911         for (lnum = 0; lnum < c->leb_cnt; lnum++) {
912                 err = ubifs_is_mapped(c, lnum);
913                 if (unlikely(err < 0))
914                         return err;
915                 if (err == 1) {
916                         c->empty = 0;
917                         break;
918                 }
919 
920                 cond_resched();
921         }
922 
923         return 0;
924 }
925 
926 /*
927  * UBIFS mount options.
928  *
929  * Opt_fast_unmount: do not run a journal commit before un-mounting
930  * Opt_norm_unmount: run a journal commit before un-mounting
931  * Opt_bulk_read: enable bulk-reads
932  * Opt_no_bulk_read: disable bulk-reads
933  * Opt_chk_data_crc: check CRCs when reading data nodes
934  * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
935  * Opt_override_compr: override default compressor
936  * Opt_err: just end of array marker
937  */
938 enum {
939         Opt_fast_unmount,
940         Opt_norm_unmount,
941         Opt_bulk_read,
942         Opt_no_bulk_read,
943         Opt_chk_data_crc,
944         Opt_no_chk_data_crc,
945         Opt_override_compr,
946         Opt_err,
947 };
948 
949 static const match_table_t tokens = {
950         {Opt_fast_unmount, "fast_unmount"},
951         {Opt_norm_unmount, "norm_unmount"},
952         {Opt_bulk_read, "bulk_read"},
953         {Opt_no_bulk_read, "no_bulk_read"},
954         {Opt_chk_data_crc, "chk_data_crc"},
955         {Opt_no_chk_data_crc, "no_chk_data_crc"},
956         {Opt_override_compr, "compr=%s"},
957         {Opt_err, NULL},
958 };
959 
960 /**
961  * parse_standard_option - parse a standard mount option.
962  * @option: the option to parse
963  *
964  * Normally, standard mount options like "sync" are passed to file-systems as
965  * flags. However, when a "rootflags=" kernel boot parameter is used, they may
966  * be present in the options string. This function tries to deal with this
967  * situation and parse standard options. Returns 0 if the option was not
968  * recognized, and the corresponding integer flag if it was.
969  *
970  * UBIFS is only interested in the "sync" option, so do not check for anything
971  * else.
972  */
973 static int parse_standard_option(const char *option)
974 {
975         ubifs_msg("parse %s", option);
976         if (!strcmp(option, "sync"))
977                 return MS_SYNCHRONOUS;
978         return 0;
979 }
980 
981 /**
982  * ubifs_parse_options - parse mount parameters.
983  * @c: UBIFS file-system description object
984  * @options: parameters to parse
985  * @is_remount: non-zero if this is FS re-mount
986  *
987  * This function parses UBIFS mount options and returns zero in case success
988  * and a negative error code in case of failure.
989  */
990 static int ubifs_parse_options(struct ubifs_info *c, char *options,
991                                int is_remount)
992 {
993         char *p;
994         substring_t args[MAX_OPT_ARGS];
995 
996         if (!options)
997                 return 0;
998 
999         while ((p = strsep(&options, ","))) {
1000                 int token;
1001 
1002                 if (!*p)
1003                         continue;
1004 
1005                 token = match_token(p, tokens, args);
1006                 switch (token) {
1007                 /*
1008                  * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
1009                  * We accept them in order to be backward-compatible. But this
1010                  * should be removed at some point.
1011                  */
1012                 case Opt_fast_unmount:
1013                         c->mount_opts.unmount_mode = 2;
1014                         break;
1015                 case Opt_norm_unmount:
1016                         c->mount_opts.unmount_mode = 1;
1017                         break;
1018                 case Opt_bulk_read:
1019                         c->mount_opts.bulk_read = 2;
1020                         c->bulk_read = 1;
1021                         break;
1022                 case Opt_no_bulk_read:
1023                         c->mount_opts.bulk_read = 1;
1024                         c->bulk_read = 0;
1025                         break;
1026                 case Opt_chk_data_crc:
1027                         c->mount_opts.chk_data_crc = 2;
1028                         c->no_chk_data_crc = 0;
1029                         break;
1030                 case Opt_no_chk_data_crc:
1031                         c->mount_opts.chk_data_crc = 1;
1032                         c->no_chk_data_crc = 1;
1033                         break;
1034                 case Opt_override_compr:
1035                 {
1036                         char *name = match_strdup(&args[0]);
1037 
1038                         if (!name)
1039                                 return -ENOMEM;
1040                         if (!strcmp(name, "none"))
1041                                 c->mount_opts.compr_type = UBIFS_COMPR_NONE;
1042                         else if (!strcmp(name, "lzo"))
1043                                 c->mount_opts.compr_type = UBIFS_COMPR_LZO;
1044                         else if (!strcmp(name, "zlib"))
1045                                 c->mount_opts.compr_type = UBIFS_COMPR_ZLIB;
1046                         else {
1047                                 ubifs_err("unknown compressor \"%s\"", name);
1048                                 kfree(name);
1049                                 return -EINVAL;
1050                         }
1051                         kfree(name);
1052                         c->mount_opts.override_compr = 1;
1053                         c->default_compr = c->mount_opts.compr_type;
1054                         break;
1055                 }
1056                 default:
1057                 {
1058                         unsigned long flag;
1059                         struct super_block *sb = c->vfs_sb;
1060 
1061                         flag = parse_standard_option(p);
1062                         if (!flag) {
1063                                 ubifs_err("unrecognized mount option \"%s\" or missing value",
1064                                           p);
1065                                 return -EINVAL;
1066                         }
1067                         sb->s_flags |= flag;
1068                         break;
1069                 }
1070                 }
1071         }
1072 
1073         return 0;
1074 }
1075 
1076 /**
1077  * destroy_journal - destroy journal data structures.
1078  * @c: UBIFS file-system description object
1079  *
1080  * This function destroys journal data structures including those that may have
1081  * been created by recovery functions.
1082  */
1083 static void destroy_journal(struct ubifs_info *c)
1084 {
1085         while (!list_empty(&c->unclean_leb_list)) {
1086                 struct ubifs_unclean_leb *ucleb;
1087 
1088                 ucleb = list_entry(c->unclean_leb_list.next,
1089                                    struct ubifs_unclean_leb, list);
1090                 list_del(&ucleb->list);
1091                 kfree(ucleb);
1092         }
1093         while (!list_empty(&c->old_buds)) {
1094                 struct ubifs_bud *bud;
1095 
1096                 bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
1097                 list_del(&bud->list);
1098                 kfree(bud);
1099         }
1100         ubifs_destroy_idx_gc(c);
1101         ubifs_destroy_size_tree(c);
1102         ubifs_tnc_close(c);
1103         free_buds(c);
1104 }
1105 
1106 /**
1107  * bu_init - initialize bulk-read information.
1108  * @c: UBIFS file-system description object
1109  */
1110 static void bu_init(struct ubifs_info *c)
1111 {
1112         ubifs_assert(c->bulk_read == 1);
1113 
1114         if (c->bu.buf)
1115                 return; /* Already initialized */
1116 
1117 again:
1118         c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN);
1119         if (!c->bu.buf) {
1120                 if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {
1121                         c->max_bu_buf_len = UBIFS_KMALLOC_OK;
1122                         goto again;
1123                 }
1124 
1125                 /* Just disable bulk-read */
1126                 ubifs_warn("cannot allocate %d bytes of memory for bulk-read, disabling it",
1127                            c->max_bu_buf_len);
1128                 c->mount_opts.bulk_read = 1;
1129                 c->bulk_read = 0;
1130                 return;
1131         }
1132 }
1133 
1134 /**
1135  * check_free_space - check if there is enough free space to mount.
1136  * @c: UBIFS file-system description object
1137  *
1138  * This function makes sure UBIFS has enough free space to be mounted in
1139  * read/write mode. UBIFS must always have some free space to allow deletions.
1140  */
1141 static int check_free_space(struct ubifs_info *c)
1142 {
1143         ubifs_assert(c->dark_wm > 0);
1144         if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
1145                 ubifs_err("insufficient free space to mount in R/W mode");
1146                 ubifs_dump_budg(c, &c->bi);
1147                 ubifs_dump_lprops(c);
1148                 return -ENOSPC;
1149         }
1150         return 0;
1151 }
1152 
1153 /**
1154  * mount_ubifs - mount UBIFS file-system.
1155  * @c: UBIFS file-system description object
1156  *
1157  * This function mounts UBIFS file system. Returns zero in case of success and
1158  * a negative error code in case of failure.
1159  */
1160 static int mount_ubifs(struct ubifs_info *c)
1161 {
1162         int err;
1163         long long x, y;
1164         size_t sz;
1165 
1166         c->ro_mount = !!(c->vfs_sb->s_flags & MS_RDONLY);
1167         err = init_constants_early(c);
1168         if (err)
1169                 return err;
1170 
1171         err = ubifs_debugging_init(c);
1172         if (err)
1173                 return err;
1174 
1175         err = check_volume_empty(c);
1176         if (err)
1177                 goto out_free;
1178 
1179         if (c->empty && (c->ro_mount || c->ro_media)) {
1180                 /*
1181                  * This UBI volume is empty, and read-only, or the file system
1182                  * is mounted read-only - we cannot format it.
1183                  */
1184                 ubifs_err("can't format empty UBI volume: read-only %s",
1185                           c->ro_media ? "UBI volume" : "mount");
1186                 err = -EROFS;
1187                 goto out_free;
1188         }
1189 
1190         if (c->ro_media && !c->ro_mount) {
1191                 ubifs_err("cannot mount read-write - read-only media");
1192                 err = -EROFS;
1193                 goto out_free;
1194         }
1195 
1196         /*
1197          * The requirement for the buffer is that it should fit indexing B-tree
1198          * height amount of integers. We assume the height if the TNC tree will
1199          * never exceed 64.
1200          */
1201         err = -ENOMEM;
1202         c->bottom_up_buf = kmalloc(BOTTOM_UP_HEIGHT * sizeof(int), GFP_KERNEL);
1203         if (!c->bottom_up_buf)
1204                 goto out_free;
1205 
1206         c->sbuf = vmalloc(c->leb_size);
1207         if (!c->sbuf)
1208                 goto out_free;
1209 
1210         if (!c->ro_mount) {
1211                 c->ileb_buf = vmalloc(c->leb_size);
1212                 if (!c->ileb_buf)
1213                         goto out_free;
1214         }
1215 
1216         if (c->bulk_read == 1)
1217                 bu_init(c);
1218 
1219         if (!c->ro_mount) {
1220                 c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ,
1221                                                GFP_KERNEL);
1222                 if (!c->write_reserve_buf)
1223                         goto out_free;
1224         }
1225 
1226         c->mounting = 1;
1227 
1228         err = ubifs_read_superblock(c);
1229         if (err)
1230                 goto out_free;
1231 
1232         /*
1233          * Make sure the compressor which is set as default in the superblock
1234          * or overridden by mount options is actually compiled in.
1235          */
1236         if (!ubifs_compr_present(c->default_compr)) {
1237                 ubifs_err("'compressor \"%s\" is not compiled in",
1238                           ubifs_compr_name(c->default_compr));
1239                 err = -ENOTSUPP;
1240                 goto out_free;
1241         }
1242 
1243         err = init_constants_sb(c);
1244         if (err)
1245                 goto out_free;
1246 
1247         sz = ALIGN(c->max_idx_node_sz, c->min_io_size);
1248         sz = ALIGN(sz + c->max_idx_node_sz, c->min_io_size);
1249         c->cbuf = kmalloc(sz, GFP_NOFS);
1250         if (!c->cbuf) {
1251                 err = -ENOMEM;
1252                 goto out_free;
1253         }
1254 
1255         err = alloc_wbufs(c);
1256         if (err)
1257                 goto out_cbuf;
1258 
1259         sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
1260         if (!c->ro_mount) {
1261                 /* Create background thread */
1262                 c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1263                 if (IS_ERR(c->bgt)) {
1264                         err = PTR_ERR(c->bgt);
1265                         c->bgt = NULL;
1266                         ubifs_err("cannot spawn \"%s\", error %d",
1267                                   c->bgt_name, err);
1268                         goto out_wbufs;
1269                 }
1270                 wake_up_process(c->bgt);
1271         }
1272 
1273         err = ubifs_read_master(c);
1274         if (err)
1275                 goto out_master;
1276 
1277         init_constants_master(c);
1278 
1279         if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
1280                 ubifs_msg("recovery needed");
1281                 c->need_recovery = 1;
1282         }
1283 
1284         if (c->need_recovery && !c->ro_mount) {
1285                 err = ubifs_recover_inl_heads(c, c->sbuf);
1286                 if (err)
1287                         goto out_master;
1288         }
1289 
1290         err = ubifs_lpt_init(c, 1, !c->ro_mount);
1291         if (err)
1292                 goto out_master;
1293 
1294         if (!c->ro_mount && c->space_fixup) {
1295                 err = ubifs_fixup_free_space(c);
1296                 if (err)
1297                         goto out_lpt;
1298         }
1299 
1300         if (!c->ro_mount) {
1301                 /*
1302                  * Set the "dirty" flag so that if we reboot uncleanly we
1303                  * will notice this immediately on the next mount.
1304                  */
1305                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1306                 err = ubifs_write_master(c);
1307                 if (err)
1308                         goto out_lpt;
1309         }
1310 
1311         err = dbg_check_idx_size(c, c->bi.old_idx_sz);
1312         if (err)
1313                 goto out_lpt;
1314 
1315         err = ubifs_replay_journal(c);
1316         if (err)
1317                 goto out_journal;
1318 
1319         /* Calculate 'min_idx_lebs' after journal replay */
1320         c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
1321 
1322         err = ubifs_mount_orphans(c, c->need_recovery, c->ro_mount);
1323         if (err)
1324                 goto out_orphans;
1325 
1326         if (!c->ro_mount) {
1327                 int lnum;
1328 
1329                 err = check_free_space(c);
1330                 if (err)
1331                         goto out_orphans;
1332 
1333                 /* Check for enough log space */
1334                 lnum = c->lhead_lnum + 1;
1335                 if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1336                         lnum = UBIFS_LOG_LNUM;
1337                 if (lnum == c->ltail_lnum) {
1338                         err = ubifs_consolidate_log(c);
1339                         if (err)
1340                                 goto out_orphans;
1341                 }
1342 
1343                 if (c->need_recovery) {
1344                         err = ubifs_recover_size(c);
1345                         if (err)
1346                                 goto out_orphans;
1347                         err = ubifs_rcvry_gc_commit(c);
1348                         if (err)
1349                                 goto out_orphans;
1350                 } else {
1351                         err = take_gc_lnum(c);
1352                         if (err)
1353                                 goto out_orphans;
1354 
1355                         /*
1356                          * GC LEB may contain garbage if there was an unclean
1357                          * reboot, and it should be un-mapped.
1358                          */
1359                         err = ubifs_leb_unmap(c, c->gc_lnum);
1360                         if (err)
1361                                 goto out_orphans;
1362                 }
1363 
1364                 err = dbg_check_lprops(c);
1365                 if (err)
1366                         goto out_orphans;
1367         } else if (c->need_recovery) {
1368                 err = ubifs_recover_size(c);
1369                 if (err)
1370                         goto out_orphans;
1371         } else {
1372                 /*
1373                  * Even if we mount read-only, we have to set space in GC LEB
1374                  * to proper value because this affects UBIFS free space
1375                  * reporting. We do not want to have a situation when
1376                  * re-mounting from R/O to R/W changes amount of free space.
1377                  */
1378                 err = take_gc_lnum(c);
1379                 if (err)
1380                         goto out_orphans;
1381         }
1382 
1383         spin_lock(&ubifs_infos_lock);
1384         list_add_tail(&c->infos_list, &ubifs_infos);
1385         spin_unlock(&ubifs_infos_lock);
1386 
1387         if (c->need_recovery) {
1388                 if (c->ro_mount)
1389                         ubifs_msg("recovery deferred");
1390                 else {
1391                         c->need_recovery = 0;
1392                         ubifs_msg("recovery completed");
1393                         /*
1394                          * GC LEB has to be empty and taken at this point. But
1395                          * the journal head LEBs may also be accounted as
1396                          * "empty taken" if they are empty.
1397                          */
1398                         ubifs_assert(c->lst.taken_empty_lebs > 0);
1399                 }
1400         } else
1401                 ubifs_assert(c->lst.taken_empty_lebs > 0);
1402 
1403         err = dbg_check_filesystem(c);
1404         if (err)
1405                 goto out_infos;
1406 
1407         err = dbg_debugfs_init_fs(c);
1408         if (err)
1409                 goto out_infos;
1410 
1411         c->mounting = 0;
1412 
1413         ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"%s",
1414                   c->vi.ubi_num, c->vi.vol_id, c->vi.name,
1415                   c->ro_mount ? ", R/O mode" : NULL);
1416         x = (long long)c->main_lebs * c->leb_size;
1417         y = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
1418         ubifs_msg("LEB size: %d bytes (%d KiB), min./max. I/O unit sizes: %d bytes/%d bytes",
1419                   c->leb_size, c->leb_size >> 10, c->min_io_size,
1420                   c->max_write_size);
1421         ubifs_msg("FS size: %lld bytes (%lld MiB, %d LEBs), journal size %lld bytes (%lld MiB, %d LEBs)",
1422                   x, x >> 20, c->main_lebs,
1423                   y, y >> 20, c->log_lebs + c->max_bud_cnt);
1424         ubifs_msg("reserved for root: %llu bytes (%llu KiB)",
1425                   c->report_rp_size, c->report_rp_size >> 10);
1426         ubifs_msg("media format: w%d/r%d (latest is w%d/r%d), UUID %pUB%s",
1427                   c->fmt_version, c->ro_compat_version,
1428                   UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION, c->uuid,
1429                   c->big_lpt ? ", big LPT model" : ", small LPT model");
1430 
1431         dbg_gen("default compressor:  %s", ubifs_compr_name(c->default_compr));
1432         dbg_gen("data journal heads:  %d",
1433                 c->jhead_cnt - NONDATA_JHEADS_CNT);
1434         dbg_gen("log LEBs:            %d (%d - %d)",
1435                 c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
1436         dbg_gen("LPT area LEBs:       %d (%d - %d)",
1437                 c->lpt_lebs, c->lpt_first, c->lpt_last);
1438         dbg_gen("orphan area LEBs:    %d (%d - %d)",
1439                 c->orph_lebs, c->orph_first, c->orph_last);
1440         dbg_gen("main area LEBs:      %d (%d - %d)",
1441                 c->main_lebs, c->main_first, c->leb_cnt - 1);
1442         dbg_gen("index LEBs:          %d", c->lst.idx_lebs);
1443         dbg_gen("total index bytes:   %lld (%lld KiB, %lld MiB)",
1444                 c->bi.old_idx_sz, c->bi.old_idx_sz >> 10,
1445                 c->bi.old_idx_sz >> 20);
1446         dbg_gen("key hash type:       %d", c->key_hash_type);
1447         dbg_gen("tree fanout:         %d", c->fanout);
1448         dbg_gen("reserved GC LEB:     %d", c->gc_lnum);
1449         dbg_gen("max. znode size      %d", c->max_znode_sz);
1450         dbg_gen("max. index node size %d", c->max_idx_node_sz);
1451         dbg_gen("node sizes:          data %zu, inode %zu, dentry %zu",
1452                 UBIFS_DATA_NODE_SZ, UBIFS_INO_NODE_SZ, UBIFS_DENT_NODE_SZ);
1453         dbg_gen("node sizes:          trun %zu, sb %zu, master %zu",
1454                 UBIFS_TRUN_NODE_SZ, UBIFS_SB_NODE_SZ, UBIFS_MST_NODE_SZ);
1455         dbg_gen("node sizes:          ref %zu, cmt. start %zu, orph %zu",
1456                 UBIFS_REF_NODE_SZ, UBIFS_CS_NODE_SZ, UBIFS_ORPH_NODE_SZ);
1457         dbg_gen("max. node sizes:     data %zu, inode %zu dentry %zu, idx %d",
1458                 UBIFS_MAX_DATA_NODE_SZ, UBIFS_MAX_INO_NODE_SZ,
1459                 UBIFS_MAX_DENT_NODE_SZ, ubifs_idx_node_sz(c, c->fanout));
1460         dbg_gen("dead watermark:      %d", c->dead_wm);
1461         dbg_gen("dark watermark:      %d", c->dark_wm);
1462         dbg_gen("LEB overhead:        %d", c->leb_overhead);
1463         x = (long long)c->main_lebs * c->dark_wm;
1464         dbg_gen("max. dark space:     %lld (%lld KiB, %lld MiB)",
1465                 x, x >> 10, x >> 20);
1466         dbg_gen("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
1467                 c->max_bud_bytes, c->max_bud_bytes >> 10,
1468                 c->max_bud_bytes >> 20);
1469         dbg_gen("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
1470                 c->bg_bud_bytes, c->bg_bud_bytes >> 10,
1471                 c->bg_bud_bytes >> 20);
1472         dbg_gen("current bud bytes    %lld (%lld KiB, %lld MiB)",
1473                 c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
1474         dbg_gen("max. seq. number:    %llu", c->max_sqnum);
1475         dbg_gen("commit number:       %llu", c->cmt_no);
1476 
1477         return 0;
1478 
1479 out_infos:
1480         spin_lock(&ubifs_infos_lock);
1481         list_del(&c->infos_list);
1482         spin_unlock(&ubifs_infos_lock);
1483 out_orphans:
1484         free_orphans(c);
1485 out_journal:
1486         destroy_journal(c);
1487 out_lpt:
1488         ubifs_lpt_free(c, 0);
1489 out_master:
1490         kfree(c->mst_node);
1491         kfree(c->rcvrd_mst_node);
1492         if (c->bgt)
1493                 kthread_stop(c->bgt);
1494 out_wbufs:
1495         free_wbufs(c);
1496 out_cbuf:
1497         kfree(c->cbuf);
1498 out_free:
1499         kfree(c->write_reserve_buf);
1500         kfree(c->bu.buf);
1501         vfree(c->ileb_buf);
1502         vfree(c->sbuf);
1503         kfree(c->bottom_up_buf);
1504         ubifs_debugging_exit(c);
1505         return err;
1506 }
1507 
1508 /**
1509  * ubifs_umount - un-mount UBIFS file-system.
1510  * @c: UBIFS file-system description object
1511  *
1512  * Note, this function is called to free allocated resourced when un-mounting,
1513  * as well as free resources when an error occurred while we were half way
1514  * through mounting (error path cleanup function). So it has to make sure the
1515  * resource was actually allocated before freeing it.
1516  */
1517 static void ubifs_umount(struct ubifs_info *c)
1518 {
1519         dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
1520                 c->vi.vol_id);
1521 
1522         dbg_debugfs_exit_fs(c);
1523         spin_lock(&ubifs_infos_lock);
1524         list_del(&c->infos_list);
1525         spin_unlock(&ubifs_infos_lock);
1526 
1527         if (c->bgt)
1528                 kthread_stop(c->bgt);
1529 
1530         destroy_journal(c);
1531         free_wbufs(c);
1532         free_orphans(c);
1533         ubifs_lpt_free(c, 0);
1534 
1535         kfree(c->cbuf);
1536         kfree(c->rcvrd_mst_node);
1537         kfree(c->mst_node);
1538         kfree(c->write_reserve_buf);
1539         kfree(c->bu.buf);
1540         vfree(c->ileb_buf);
1541         vfree(c->sbuf);
1542         kfree(c->bottom_up_buf);
1543         ubifs_debugging_exit(c);
1544 }
1545 
1546 /**
1547  * ubifs_remount_rw - re-mount in read-write mode.
1548  * @c: UBIFS file-system description object
1549  *
1550  * UBIFS avoids allocating many unnecessary resources when mounted in read-only
1551  * mode. This function allocates the needed resources and re-mounts UBIFS in
1552  * read-write mode.
1553  */
1554 static int ubifs_remount_rw(struct ubifs_info *c)
1555 {
1556         int err, lnum;
1557 
1558         if (c->rw_incompat) {
1559                 ubifs_err("the file-system is not R/W-compatible");
1560                 ubifs_msg("on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
1561                           c->fmt_version, c->ro_compat_version,
1562                           UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
1563                 return -EROFS;
1564         }
1565 
1566         mutex_lock(&c->umount_mutex);
1567         dbg_save_space_info(c);
1568         c->remounting_rw = 1;
1569         c->ro_mount = 0;
1570 
1571         if (c->space_fixup) {
1572                 err = ubifs_fixup_free_space(c);
1573                 if (err)
1574                         return err;
1575         }
1576 
1577         err = check_free_space(c);
1578         if (err)
1579                 goto out;
1580 
1581         if (c->old_leb_cnt != c->leb_cnt) {
1582                 struct ubifs_sb_node *sup;
1583 
1584                 sup = ubifs_read_sb_node(c);
1585                 if (IS_ERR(sup)) {
1586                         err = PTR_ERR(sup);
1587                         goto out;
1588                 }
1589                 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
1590                 err = ubifs_write_sb_node(c, sup);
1591                 kfree(sup);
1592                 if (err)
1593                         goto out;
1594         }
1595 
1596         if (c->need_recovery) {
1597                 ubifs_msg("completing deferred recovery");
1598                 err = ubifs_write_rcvrd_mst_node(c);
1599                 if (err)
1600                         goto out;
1601                 err = ubifs_recover_size(c);
1602                 if (err)
1603                         goto out;
1604                 err = ubifs_clean_lebs(c, c->sbuf);
1605                 if (err)
1606                         goto out;
1607                 err = ubifs_recover_inl_heads(c, c->sbuf);
1608                 if (err)
1609                         goto out;
1610         } else {
1611                 /* A readonly mount is not allowed to have orphans */
1612                 ubifs_assert(c->tot_orphans == 0);
1613                 err = ubifs_clear_orphans(c);
1614                 if (err)
1615                         goto out;
1616         }
1617 
1618         if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
1619                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1620                 err = ubifs_write_master(c);
1621                 if (err)
1622                         goto out;
1623         }
1624 
1625         c->ileb_buf = vmalloc(c->leb_size);
1626         if (!c->ileb_buf) {
1627                 err = -ENOMEM;
1628                 goto out;
1629         }
1630 
1631         c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ, GFP_KERNEL);
1632         if (!c->write_reserve_buf)
1633                 goto out;
1634 
1635         err = ubifs_lpt_init(c, 0, 1);
1636         if (err)
1637                 goto out;
1638 
1639         /* Create background thread */
1640         c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1641         if (IS_ERR(c->bgt)) {
1642                 err = PTR_ERR(c->bgt);
1643                 c->bgt = NULL;
1644                 ubifs_err("cannot spawn \"%s\", error %d",
1645                           c->bgt_name, err);
1646                 goto out;
1647         }
1648         wake_up_process(c->bgt);
1649 
1650         c->orph_buf = vmalloc(c->leb_size);
1651         if (!c->orph_buf) {
1652                 err = -ENOMEM;
1653                 goto out;
1654         }
1655 
1656         /* Check for enough log space */
1657         lnum = c->lhead_lnum + 1;
1658         if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1659                 lnum = UBIFS_LOG_LNUM;
1660         if (lnum == c->ltail_lnum) {
1661                 err = ubifs_consolidate_log(c);
1662                 if (err)
1663                         goto out;
1664         }
1665 
1666         if (c->need_recovery)
1667                 err = ubifs_rcvry_gc_commit(c);
1668         else
1669                 err = ubifs_leb_unmap(c, c->gc_lnum);
1670         if (err)
1671                 goto out;
1672 
1673         dbg_gen("re-mounted read-write");
1674         c->remounting_rw = 0;
1675 
1676         if (c->need_recovery) {
1677                 c->need_recovery = 0;
1678                 ubifs_msg("deferred recovery completed");
1679         } else {
1680                 /*
1681                  * Do not run the debugging space check if the were doing
1682                  * recovery, because when we saved the information we had the
1683                  * file-system in a state where the TNC and lprops has been
1684                  * modified in memory, but all the I/O operations (including a
1685                  * commit) were deferred. So the file-system was in
1686                  * "non-committed" state. Now the file-system is in committed
1687                  * state, and of course the amount of free space will change
1688                  * because, for example, the old index size was imprecise.
1689                  */
1690                 err = dbg_check_space_info(c);
1691         }
1692 
1693         mutex_unlock(&c->umount_mutex);
1694         return err;
1695 
1696 out:
1697         c->ro_mount = 1;
1698         vfree(c->orph_buf);
1699         c->orph_buf = NULL;
1700         if (c->bgt) {
1701                 kthread_stop(c->bgt);
1702                 c->bgt = NULL;
1703         }
1704         free_wbufs(c);
1705         kfree(c->write_reserve_buf);
1706         c->write_reserve_buf = NULL;
1707         vfree(c->ileb_buf);
1708         c->ileb_buf = NULL;
1709         ubifs_lpt_free(c, 1);
1710         c->remounting_rw = 0;
1711         mutex_unlock(&c->umount_mutex);
1712         return err;
1713 }
1714 
1715 /**
1716  * ubifs_remount_ro - re-mount in read-only mode.
1717  * @c: UBIFS file-system description object
1718  *
1719  * We assume VFS has stopped writing. Possibly the background thread could be
1720  * running a commit, however kthread_stop will wait in that case.
1721  */
1722 static void ubifs_remount_ro(struct ubifs_info *c)
1723 {
1724         int i, err;
1725 
1726         ubifs_assert(!c->need_recovery);
1727         ubifs_assert(!c->ro_mount);
1728 
1729         mutex_lock(&c->umount_mutex);
1730         if (c->bgt) {
1731                 kthread_stop(c->bgt);
1732                 c->bgt = NULL;
1733         }
1734 
1735         dbg_save_space_info(c);
1736 
1737         for (i = 0; i < c->jhead_cnt; i++)
1738                 ubifs_wbuf_sync(&c->jheads[i].wbuf);
1739 
1740         c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1741         c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1742         c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1743         err = ubifs_write_master(c);
1744         if (err)
1745                 ubifs_ro_mode(c, err);
1746 
1747         vfree(c->orph_buf);
1748         c->orph_buf = NULL;
1749         kfree(c->write_reserve_buf);
1750         c->write_reserve_buf = NULL;
1751         vfree(c->ileb_buf);
1752         c->ileb_buf = NULL;
1753         ubifs_lpt_free(c, 1);
1754         c->ro_mount = 1;
1755         err = dbg_check_space_info(c);
1756         if (err)
1757                 ubifs_ro_mode(c, err);
1758         mutex_unlock(&c->umount_mutex);
1759 }
1760 
1761 static void ubifs_put_super(struct super_block *sb)
1762 {
1763         int i;
1764         struct ubifs_info *c = sb->s_fs_info;
1765 
1766         ubifs_msg("un-mount UBI device %d, volume %d", c->vi.ubi_num,
1767                   c->vi.vol_id);
1768 
1769         /*
1770          * The following asserts are only valid if there has not been a failure
1771          * of the media. For example, there will be dirty inodes if we failed
1772          * to write them back because of I/O errors.
1773          */
1774         if (!c->ro_error) {
1775                 ubifs_assert(c->bi.idx_growth == 0);
1776                 ubifs_assert(c->bi.dd_growth == 0);
1777                 ubifs_assert(c->bi.data_growth == 0);
1778         }
1779 
1780         /*
1781          * The 'c->umount_lock' prevents races between UBIFS memory shrinker
1782          * and file system un-mount. Namely, it prevents the shrinker from
1783          * picking this superblock for shrinking - it will be just skipped if
1784          * the mutex is locked.
1785          */
1786         mutex_lock(&c->umount_mutex);
1787         if (!c->ro_mount) {
1788                 /*
1789                  * First of all kill the background thread to make sure it does
1790                  * not interfere with un-mounting and freeing resources.
1791                  */
1792                 if (c->bgt) {
1793                         kthread_stop(c->bgt);
1794                         c->bgt = NULL;
1795                 }
1796 
1797                 /*
1798                  * On fatal errors c->ro_error is set to 1, in which case we do
1799                  * not write the master node.
1800                  */
1801                 if (!c->ro_error) {
1802                         int err;
1803 
1804                         /* Synchronize write-buffers */
1805                         for (i = 0; i < c->jhead_cnt; i++)
1806                                 ubifs_wbuf_sync(&c->jheads[i].wbuf);
1807 
1808                         /*
1809                          * We are being cleanly unmounted which means the
1810                          * orphans were killed - indicate this in the master
1811                          * node. Also save the reserved GC LEB number.
1812                          */
1813                         c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1814                         c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1815                         c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1816                         err = ubifs_write_master(c);
1817                         if (err)
1818                                 /*
1819                                  * Recovery will attempt to fix the master area
1820                                  * next mount, so we just print a message and
1821                                  * continue to unmount normally.
1822                                  */
1823                                 ubifs_err("failed to write master node, error %d",
1824                                           err);
1825                 } else {
1826                         for (i = 0; i < c->jhead_cnt; i++)
1827                                 /* Make sure write-buffer timers are canceled */
1828                                 hrtimer_cancel(&c->jheads[i].wbuf.timer);
1829                 }
1830         }
1831 
1832         ubifs_umount(c);
1833         bdi_destroy(&c->bdi);
1834         ubi_close_volume(c->ubi);
1835         mutex_unlock(&c->umount_mutex);
1836 }
1837 
1838 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
1839 {
1840         int err;
1841         struct ubifs_info *c = sb->s_fs_info;
1842 
1843         dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
1844 
1845         err = ubifs_parse_options(c, data, 1);
1846         if (err) {
1847                 ubifs_err("invalid or unknown remount parameter");
1848                 return err;
1849         }
1850 
1851         if (c->ro_mount && !(*flags & MS_RDONLY)) {
1852                 if (c->ro_error) {
1853                         ubifs_msg("cannot re-mount R/W due to prior errors");
1854                         return -EROFS;
1855                 }
1856                 if (c->ro_media) {
1857                         ubifs_msg("cannot re-mount R/W - UBI volume is R/O");
1858                         return -EROFS;
1859                 }
1860                 err = ubifs_remount_rw(c);
1861                 if (err)
1862                         return err;
1863         } else if (!c->ro_mount && (*flags & MS_RDONLY)) {
1864                 if (c->ro_error) {
1865                         ubifs_msg("cannot re-mount R/O due to prior errors");
1866                         return -EROFS;
1867                 }
1868                 ubifs_remount_ro(c);
1869         }
1870 
1871         if (c->bulk_read == 1)
1872                 bu_init(c);
1873         else {
1874                 dbg_gen("disable bulk-read");
1875                 kfree(c->bu.buf);
1876                 c->bu.buf = NULL;
1877         }
1878 
1879         ubifs_assert(c->lst.taken_empty_lebs > 0);
1880         return 0;
1881 }
1882 
1883 const struct super_operations ubifs_super_operations = {
1884         .alloc_inode   = ubifs_alloc_inode,
1885         .destroy_inode = ubifs_destroy_inode,
1886         .put_super     = ubifs_put_super,
1887         .write_inode   = ubifs_write_inode,
1888         .evict_inode   = ubifs_evict_inode,
1889         .statfs        = ubifs_statfs,
1890         .dirty_inode   = ubifs_dirty_inode,
1891         .remount_fs    = ubifs_remount_fs,
1892         .show_options  = ubifs_show_options,
1893         .sync_fs       = ubifs_sync_fs,
1894 };
1895 
1896 /**
1897  * open_ubi - parse UBI device name string and open the UBI device.
1898  * @name: UBI volume name
1899  * @mode: UBI volume open mode
1900  *
1901  * The primary method of mounting UBIFS is by specifying the UBI volume
1902  * character device node path. However, UBIFS may also be mounted withoug any
1903  * character device node using one of the following methods:
1904  *
1905  * o ubiX_Y    - mount UBI device number X, volume Y;
1906  * o ubiY      - mount UBI device number 0, volume Y;
1907  * o ubiX:NAME - mount UBI device X, volume with name NAME;
1908  * o ubi:NAME  - mount UBI device 0, volume with name NAME.
1909  *
1910  * Alternative '!' separator may be used instead of ':' (because some shells
1911  * like busybox may interpret ':' as an NFS host name separator). This function
1912  * returns UBI volume description object in case of success and a negative
1913  * error code in case of failure.
1914  */
1915 static struct ubi_volume_desc *open_ubi(const char *name, int mode)
1916 {
1917         struct ubi_volume_desc *ubi;
1918         int dev, vol;
1919         char *endptr;
1920 
1921         /* First, try to open using the device node path method */
1922         ubi = ubi_open_volume_path(name, mode);
1923         if (!IS_ERR(ubi))
1924                 return ubi;
1925 
1926         /* Try the "nodev" method */
1927         if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
1928                 return ERR_PTR(-EINVAL);
1929 
1930         /* ubi:NAME method */
1931         if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
1932                 return ubi_open_volume_nm(0, name + 4, mode);
1933 
1934         if (!isdigit(name[3]))
1935                 return ERR_PTR(-EINVAL);
1936 
1937         dev = simple_strtoul(name + 3, &endptr, 0);
1938 
1939         /* ubiY method */
1940         if (*endptr == '\0')
1941                 return ubi_open_volume(0, dev, mode);
1942 
1943         /* ubiX_Y method */
1944         if (*endptr == '_' && isdigit(endptr[1])) {
1945                 vol = simple_strtoul(endptr + 1, &endptr, 0);
1946                 if (*endptr != '\0')
1947                         return ERR_PTR(-EINVAL);
1948                 return ubi_open_volume(dev, vol, mode);
1949         }
1950 
1951         /* ubiX:NAME method */
1952         if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
1953                 return ubi_open_volume_nm(dev, ++endptr, mode);
1954 
1955         return ERR_PTR(-EINVAL);
1956 }
1957 
1958 static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
1959 {
1960         struct ubifs_info *c;
1961 
1962         c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
1963         if (c) {
1964                 spin_lock_init(&c->cnt_lock);
1965                 spin_lock_init(&c->cs_lock);
1966                 spin_lock_init(&c->buds_lock);
1967                 spin_lock_init(&c->space_lock);
1968                 spin_lock_init(&c->orphan_lock);
1969                 init_rwsem(&c->commit_sem);
1970                 mutex_init(&c->lp_mutex);
1971                 mutex_init(&c->tnc_mutex);
1972                 mutex_init(&c->log_mutex);
1973                 mutex_init(&c->mst_mutex);
1974                 mutex_init(&c->umount_mutex);
1975                 mutex_init(&c->bu_mutex);
1976                 mutex_init(&c->write_reserve_mutex);
1977                 init_waitqueue_head(&c->cmt_wq);
1978                 c->buds = RB_ROOT;
1979                 c->old_idx = RB_ROOT;
1980                 c->size_tree = RB_ROOT;
1981                 c->orph_tree = RB_ROOT;
1982                 INIT_LIST_HEAD(&c->infos_list);
1983                 INIT_LIST_HEAD(&c->idx_gc);
1984                 INIT_LIST_HEAD(&c->replay_list);
1985                 INIT_LIST_HEAD(&c->replay_buds);
1986                 INIT_LIST_HEAD(&c->uncat_list);
1987                 INIT_LIST_HEAD(&c->empty_list);
1988                 INIT_LIST_HEAD(&c->freeable_list);
1989                 INIT_LIST_HEAD(&c->frdi_idx_list);
1990                 INIT_LIST_HEAD(&c->unclean_leb_list);
1991                 INIT_LIST_HEAD(&c->old_buds);
1992                 INIT_LIST_HEAD(&c->orph_list);
1993                 INIT_LIST_HEAD(&c->orph_new);
1994                 c->no_chk_data_crc = 1;
1995 
1996                 c->highest_inum = UBIFS_FIRST_INO;
1997                 c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
1998 
1999                 ubi_get_volume_info(ubi, &c->vi);
2000                 ubi_get_device_info(c->vi.ubi_num, &c->di);
2001         }
2002         return c;
2003 }
2004 
2005 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
2006 {
2007         struct ubifs_info *c = sb->s_fs_info;
2008         struct inode *root;
2009         int err;
2010 
2011         c->vfs_sb = sb;
2012         /* Re-open the UBI device in read-write mode */
2013         c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
2014         if (IS_ERR(c->ubi)) {
2015                 err = PTR_ERR(c->ubi);
2016                 goto out;
2017         }
2018 
2019         /*
2020          * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
2021          * UBIFS, I/O is not deferred, it is done immediately in readpage,
2022          * which means the user would have to wait not just for their own I/O
2023          * but the read-ahead I/O as well i.e. completely pointless.
2024          *
2025          * Read-ahead will be disabled because @c->bdi.ra_pages is 0.
2026          */
2027         c->bdi.name = "ubifs",
2028         c->bdi.capabilities = BDI_CAP_MAP_COPY;
2029         err  = bdi_init(&c->bdi);
2030         if (err)
2031                 goto out_close;
2032         err = bdi_register(&c->bdi, NULL, "ubifs_%d_%d",
2033                            c->vi.ubi_num, c->vi.vol_id);
2034         if (err)
2035                 goto out_bdi;
2036 
2037         err = ubifs_parse_options(c, data, 0);
2038         if (err)
2039                 goto out_bdi;
2040 
2041         sb->s_bdi = &c->bdi;
2042         sb->s_fs_info = c;
2043         sb->s_magic = UBIFS_SUPER_MAGIC;
2044         sb->s_blocksize = UBIFS_BLOCK_SIZE;
2045         sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
2046         sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
2047         if (c->max_inode_sz > MAX_LFS_FILESIZE)
2048                 sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
2049         sb->s_op = &ubifs_super_operations;
2050 
2051         mutex_lock(&c->umount_mutex);
2052         err = mount_ubifs(c);
2053         if (err) {
2054                 ubifs_assert(err < 0);
2055                 goto out_unlock;
2056         }
2057 
2058         /* Read the root inode */
2059         root = ubifs_iget(sb, UBIFS_ROOT_INO);
2060         if (IS_ERR(root)) {
2061                 err = PTR_ERR(root);
2062                 goto out_umount;
2063         }
2064 
2065         sb->s_root = d_make_root(root);
2066         if (!sb->s_root)
2067                 goto out_umount;
2068 
2069         mutex_unlock(&c->umount_mutex);
2070         return 0;
2071 
2072 out_umount:
2073         ubifs_umount(c);
2074 out_unlock:
2075         mutex_unlock(&c->umount_mutex);
2076 out_bdi:
2077         bdi_destroy(&c->bdi);
2078 out_close:
2079         ubi_close_volume(c->ubi);
2080 out:
2081         return err;
2082 }
2083 
2084 static int sb_test(struct super_block *sb, void *data)
2085 {
2086         struct ubifs_info *c1 = data;
2087         struct ubifs_info *c = sb->s_fs_info;
2088 
2089         return c->vi.cdev == c1->vi.cdev;
2090 }
2091 
2092 static int sb_set(struct super_block *sb, void *data)
2093 {
2094         sb->s_fs_info = data;
2095         return set_anon_super(sb, NULL);
2096 }
2097 
2098 static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
2099                         const char *name, void *data)
2100 {
2101         struct ubi_volume_desc *ubi;
2102         struct ubifs_info *c;
2103         struct super_block *sb;
2104         int err;
2105 
2106         dbg_gen("name %s, flags %#x", name, flags);
2107 
2108         /*
2109          * Get UBI device number and volume ID. Mount it read-only so far
2110          * because this might be a new mount point, and UBI allows only one
2111          * read-write user at a time.
2112          */
2113         ubi = open_ubi(name, UBI_READONLY);
2114         if (IS_ERR(ubi)) {
2115                 ubifs_err("cannot open \"%s\", error %d",
2116                           name, (int)PTR_ERR(ubi));
2117                 return ERR_CAST(ubi);
2118         }
2119 
2120         c = alloc_ubifs_info(ubi);
2121         if (!c) {
2122                 err = -ENOMEM;
2123                 goto out_close;
2124         }
2125 
2126         dbg_gen("opened ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
2127 
2128         sb = sget(fs_type, sb_test, sb_set, flags, c);
2129         if (IS_ERR(sb)) {
2130                 err = PTR_ERR(sb);
2131                 kfree(c);
2132                 goto out_close;
2133         }
2134 
2135         if (sb->s_root) {
2136                 struct ubifs_info *c1 = sb->s_fs_info;
2137                 kfree(c);
2138                 /* A new mount point for already mounted UBIFS */
2139                 dbg_gen("this ubi volume is already mounted");
2140                 if (!!(flags & MS_RDONLY) != c1->ro_mount) {
2141                         err = -EBUSY;
2142                         goto out_deact;
2143                 }
2144         } else {
2145                 err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
2146                 if (err)
2147                         goto out_deact;
2148                 /* We do not support atime */
2149                 sb->s_flags |= MS_ACTIVE | MS_NOATIME;
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                 ubifs_err("VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
2245                           (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                                 &inode_slab_ctor);
2253         if (!ubifs_inode_slab)
2254                 return -ENOMEM;
2255 
2256         register_shrinker(&ubifs_shrinker_info);
2257 
2258         err = ubifs_compressors_init();
2259         if (err)
2260                 goto out_shrinker;
2261 
2262         err = dbg_debugfs_init();
2263         if (err)
2264                 goto out_compr;
2265 
2266         err = register_filesystem(&ubifs_fs_type);
2267         if (err) {
2268                 ubifs_err("cannot register file system, error %d", err);
2269                 goto out_dbg;
2270         }
2271         return 0;
2272 
2273 out_dbg:
2274         dbg_debugfs_exit();
2275 out_compr:
2276         ubifs_compressors_exit();
2277 out_shrinker:
2278         unregister_shrinker(&ubifs_shrinker_info);
2279         kmem_cache_destroy(ubifs_inode_slab);
2280         return err;
2281 }
2282 /* late_initcall to let compressors initialize first */
2283 late_initcall(ubifs_init);
2284 
2285 static void __exit ubifs_exit(void)
2286 {
2287         ubifs_assert(list_empty(&ubifs_infos));
2288         ubifs_assert(atomic_long_read(&ubifs_clean_zn_cnt) == 0);
2289 
2290         dbg_debugfs_exit();
2291         ubifs_compressors_exit();
2292         unregister_shrinker(&ubifs_shrinker_info);
2293 
2294         /*
2295          * Make sure all delayed rcu free inodes are flushed before we
2296          * destroy cache.
2297          */
2298         rcu_barrier();
2299         kmem_cache_destroy(ubifs_inode_slab);
2300         unregister_filesystem(&ubifs_fs_type);
2301 }
2302 module_exit(ubifs_exit);
2303 
2304 MODULE_LICENSE("GPL");
2305 MODULE_VERSION(__stringify(UBIFS_VERSION));
2306 MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
2307 MODULE_DESCRIPTION("UBIFS - UBI File System");
2308 

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