Version:  2.0.40 2.2.26 2.4.37 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 4.2

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

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