Merge branch 'for-rmk/samsung6' of git://git.fluff.org/bjdooks/linux into devel-stable
[linux-2.6.git] / drivers / mtd / ubi / cdev.c
1 /*
2  * Copyright (c) International Business Machines Corp., 2006
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12  * the GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  *
18  * Author: Artem Bityutskiy (Битюцкий Артём)
19  */
20
21 /*
22  * This file includes implementation of UBI character device operations.
23  *
24  * There are two kinds of character devices in UBI: UBI character devices and
25  * UBI volume character devices. UBI character devices allow users to
26  * manipulate whole volumes: create, remove, and re-size them. Volume character
27  * devices provide volume I/O capabilities.
28  *
29  * Major and minor numbers are assigned dynamically to both UBI and volume
30  * character devices.
31  *
32  * Well, there is the third kind of character devices - the UBI control
33  * character device, which allows to manipulate by UBI devices - create and
34  * delete them. In other words, it is used for attaching and detaching MTD
35  * devices.
36  */
37
38 #include <linux/module.h>
39 #include <linux/stat.h>
40 #include <linux/ioctl.h>
41 #include <linux/capability.h>
42 #include <linux/uaccess.h>
43 #include <linux/compat.h>
44 #include <linux/math64.h>
45 #include <mtd/ubi-user.h>
46 #include "ubi.h"
47
48 /**
49  * get_exclusive - get exclusive access to an UBI volume.
50  * @desc: volume descriptor
51  *
52  * This function changes UBI volume open mode to "exclusive". Returns previous
53  * mode value (positive integer) in case of success and a negative error code
54  * in case of failure.
55  */
56 static int get_exclusive(struct ubi_volume_desc *desc)
57 {
58         int users, err;
59         struct ubi_volume *vol = desc->vol;
60
61         spin_lock(&vol->ubi->volumes_lock);
62         users = vol->readers + vol->writers + vol->exclusive;
63         ubi_assert(users > 0);
64         if (users > 1) {
65                 dbg_err("%d users for volume %d", users, vol->vol_id);
66                 err = -EBUSY;
67         } else {
68                 vol->readers = vol->writers = 0;
69                 vol->exclusive = 1;
70                 err = desc->mode;
71                 desc->mode = UBI_EXCLUSIVE;
72         }
73         spin_unlock(&vol->ubi->volumes_lock);
74
75         return err;
76 }
77
78 /**
79  * revoke_exclusive - revoke exclusive mode.
80  * @desc: volume descriptor
81  * @mode: new mode to switch to
82  */
83 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
84 {
85         struct ubi_volume *vol = desc->vol;
86
87         spin_lock(&vol->ubi->volumes_lock);
88         ubi_assert(vol->readers == 0 && vol->writers == 0);
89         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
90         vol->exclusive = 0;
91         if (mode == UBI_READONLY)
92                 vol->readers = 1;
93         else if (mode == UBI_READWRITE)
94                 vol->writers = 1;
95         else
96                 vol->exclusive = 1;
97         spin_unlock(&vol->ubi->volumes_lock);
98
99         desc->mode = mode;
100 }
101
102 static int vol_cdev_open(struct inode *inode, struct file *file)
103 {
104         struct ubi_volume_desc *desc;
105         int vol_id = iminor(inode) - 1, mode, ubi_num;
106
107         ubi_num = ubi_major2num(imajor(inode));
108         if (ubi_num < 0)
109                 return ubi_num;
110
111         if (file->f_mode & FMODE_WRITE)
112                 mode = UBI_READWRITE;
113         else
114                 mode = UBI_READONLY;
115
116         dbg_gen("open device %d, volume %d, mode %d",
117                 ubi_num, vol_id, mode);
118
119         desc = ubi_open_volume(ubi_num, vol_id, mode);
120         if (IS_ERR(desc))
121                 return PTR_ERR(desc);
122
123         file->private_data = desc;
124         return 0;
125 }
126
127 static int vol_cdev_release(struct inode *inode, struct file *file)
128 {
129         struct ubi_volume_desc *desc = file->private_data;
130         struct ubi_volume *vol = desc->vol;
131
132         dbg_gen("release device %d, volume %d, mode %d",
133                 vol->ubi->ubi_num, vol->vol_id, desc->mode);
134
135         if (vol->updating) {
136                 ubi_warn("update of volume %d not finished, volume is damaged",
137                          vol->vol_id);
138                 ubi_assert(!vol->changing_leb);
139                 vol->updating = 0;
140                 vfree(vol->upd_buf);
141         } else if (vol->changing_leb) {
142                 dbg_gen("only %lld of %lld bytes received for atomic LEB change"
143                         " for volume %d:%d, cancel", vol->upd_received,
144                         vol->upd_bytes, vol->ubi->ubi_num, vol->vol_id);
145                 vol->changing_leb = 0;
146                 vfree(vol->upd_buf);
147         }
148
149         ubi_close_volume(desc);
150         return 0;
151 }
152
153 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
154 {
155         struct ubi_volume_desc *desc = file->private_data;
156         struct ubi_volume *vol = desc->vol;
157         loff_t new_offset;
158
159         if (vol->updating) {
160                  /* Update is in progress, seeking is prohibited */
161                 dbg_err("updating");
162                 return -EBUSY;
163         }
164
165         switch (origin) {
166         case 0: /* SEEK_SET */
167                 new_offset = offset;
168                 break;
169         case 1: /* SEEK_CUR */
170                 new_offset = file->f_pos + offset;
171                 break;
172         case 2: /* SEEK_END */
173                 new_offset = vol->used_bytes + offset;
174                 break;
175         default:
176                 return -EINVAL;
177         }
178
179         if (new_offset < 0 || new_offset > vol->used_bytes) {
180                 dbg_err("bad seek %lld", new_offset);
181                 return -EINVAL;
182         }
183
184         dbg_gen("seek volume %d, offset %lld, origin %d, new offset %lld",
185                 vol->vol_id, offset, origin, new_offset);
186
187         file->f_pos = new_offset;
188         return new_offset;
189 }
190
191 static int vol_cdev_fsync(struct file *file, struct dentry *dentry,
192                           int datasync)
193 {
194         struct ubi_volume_desc *desc = file->private_data;
195         struct ubi_device *ubi = desc->vol->ubi;
196
197         return ubi_sync(ubi->ubi_num);
198 }
199
200
201 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
202                              loff_t *offp)
203 {
204         struct ubi_volume_desc *desc = file->private_data;
205         struct ubi_volume *vol = desc->vol;
206         struct ubi_device *ubi = vol->ubi;
207         int err, lnum, off, len,  tbuf_size;
208         size_t count_save = count;
209         void *tbuf;
210
211         dbg_gen("read %zd bytes from offset %lld of volume %d",
212                 count, *offp, vol->vol_id);
213
214         if (vol->updating) {
215                 dbg_err("updating");
216                 return -EBUSY;
217         }
218         if (vol->upd_marker) {
219                 dbg_err("damaged volume, update marker is set");
220                 return -EBADF;
221         }
222         if (*offp == vol->used_bytes || count == 0)
223                 return 0;
224
225         if (vol->corrupted)
226                 dbg_gen("read from corrupted volume %d", vol->vol_id);
227
228         if (*offp + count > vol->used_bytes)
229                 count_save = count = vol->used_bytes - *offp;
230
231         tbuf_size = vol->usable_leb_size;
232         if (count < tbuf_size)
233                 tbuf_size = ALIGN(count, ubi->min_io_size);
234         tbuf = vmalloc(tbuf_size);
235         if (!tbuf)
236                 return -ENOMEM;
237
238         len = count > tbuf_size ? tbuf_size : count;
239         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
240
241         do {
242                 cond_resched();
243
244                 if (off + len >= vol->usable_leb_size)
245                         len = vol->usable_leb_size - off;
246
247                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
248                 if (err)
249                         break;
250
251                 off += len;
252                 if (off == vol->usable_leb_size) {
253                         lnum += 1;
254                         off -= vol->usable_leb_size;
255                 }
256
257                 count -= len;
258                 *offp += len;
259
260                 err = copy_to_user(buf, tbuf, len);
261                 if (err) {
262                         err = -EFAULT;
263                         break;
264                 }
265
266                 buf += len;
267                 len = count > tbuf_size ? tbuf_size : count;
268         } while (count);
269
270         vfree(tbuf);
271         return err ? err : count_save - count;
272 }
273
274 /*
275  * This function allows to directly write to dynamic UBI volumes, without
276  * issuing the volume update operation.
277  */
278 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
279                                      size_t count, loff_t *offp)
280 {
281         struct ubi_volume_desc *desc = file->private_data;
282         struct ubi_volume *vol = desc->vol;
283         struct ubi_device *ubi = vol->ubi;
284         int lnum, off, len, tbuf_size, err = 0;
285         size_t count_save = count;
286         char *tbuf;
287
288         if (!vol->direct_writes)
289                 return -EPERM;
290
291         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
292                 count, *offp, vol->vol_id);
293
294         if (vol->vol_type == UBI_STATIC_VOLUME)
295                 return -EROFS;
296
297         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
298         if (off & (ubi->min_io_size - 1)) {
299                 dbg_err("unaligned position");
300                 return -EINVAL;
301         }
302
303         if (*offp + count > vol->used_bytes)
304                 count_save = count = vol->used_bytes - *offp;
305
306         /* We can write only in fractions of the minimum I/O unit */
307         if (count & (ubi->min_io_size - 1)) {
308                 dbg_err("unaligned write length");
309                 return -EINVAL;
310         }
311
312         tbuf_size = vol->usable_leb_size;
313         if (count < tbuf_size)
314                 tbuf_size = ALIGN(count, ubi->min_io_size);
315         tbuf = vmalloc(tbuf_size);
316         if (!tbuf)
317                 return -ENOMEM;
318
319         len = count > tbuf_size ? tbuf_size : count;
320
321         while (count) {
322                 cond_resched();
323
324                 if (off + len >= vol->usable_leb_size)
325                         len = vol->usable_leb_size - off;
326
327                 err = copy_from_user(tbuf, buf, len);
328                 if (err) {
329                         err = -EFAULT;
330                         break;
331                 }
332
333                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
334                                         UBI_UNKNOWN);
335                 if (err)
336                         break;
337
338                 off += len;
339                 if (off == vol->usable_leb_size) {
340                         lnum += 1;
341                         off -= vol->usable_leb_size;
342                 }
343
344                 count -= len;
345                 *offp += len;
346                 buf += len;
347                 len = count > tbuf_size ? tbuf_size : count;
348         }
349
350         vfree(tbuf);
351         return err ? err : count_save - count;
352 }
353
354 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
355                               size_t count, loff_t *offp)
356 {
357         int err = 0;
358         struct ubi_volume_desc *desc = file->private_data;
359         struct ubi_volume *vol = desc->vol;
360         struct ubi_device *ubi = vol->ubi;
361
362         if (!vol->updating && !vol->changing_leb)
363                 return vol_cdev_direct_write(file, buf, count, offp);
364
365         if (vol->updating)
366                 err = ubi_more_update_data(ubi, vol, buf, count);
367         else
368                 err = ubi_more_leb_change_data(ubi, vol, buf, count);
369
370         if (err < 0) {
371                 ubi_err("cannot accept more %zd bytes of data, error %d",
372                         count, err);
373                 return err;
374         }
375
376         if (err) {
377                 /*
378                  * The operation is finished, @err contains number of actually
379                  * written bytes.
380                  */
381                 count = err;
382
383                 if (vol->changing_leb) {
384                         revoke_exclusive(desc, UBI_READWRITE);
385                         return count;
386                 }
387
388                 err = ubi_check_volume(ubi, vol->vol_id);
389                 if (err < 0)
390                         return err;
391
392                 if (err) {
393                         ubi_warn("volume %d on UBI device %d is corrupted",
394                                  vol->vol_id, ubi->ubi_num);
395                         vol->corrupted = 1;
396                 }
397                 vol->checked = 1;
398                 ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
399                 revoke_exclusive(desc, UBI_READWRITE);
400         }
401
402         return count;
403 }
404
405 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
406                            unsigned long arg)
407 {
408         int err = 0;
409         struct ubi_volume_desc *desc = file->private_data;
410         struct ubi_volume *vol = desc->vol;
411         struct ubi_device *ubi = vol->ubi;
412         void __user *argp = (void __user *)arg;
413
414         switch (cmd) {
415         /* Volume update command */
416         case UBI_IOCVOLUP:
417         {
418                 int64_t bytes, rsvd_bytes;
419
420                 if (!capable(CAP_SYS_RESOURCE)) {
421                         err = -EPERM;
422                         break;
423                 }
424
425                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
426                 if (err) {
427                         err = -EFAULT;
428                         break;
429                 }
430
431                 if (desc->mode == UBI_READONLY) {
432                         err = -EROFS;
433                         break;
434                 }
435
436                 rsvd_bytes = (long long)vol->reserved_pebs *
437                                         ubi->leb_size-vol->data_pad;
438                 if (bytes < 0 || bytes > rsvd_bytes) {
439                         err = -EINVAL;
440                         break;
441                 }
442
443                 err = get_exclusive(desc);
444                 if (err < 0)
445                         break;
446
447                 err = ubi_start_update(ubi, vol, bytes);
448                 if (bytes == 0)
449                         revoke_exclusive(desc, UBI_READWRITE);
450                 break;
451         }
452
453         /* Atomic logical eraseblock change command */
454         case UBI_IOCEBCH:
455         {
456                 struct ubi_leb_change_req req;
457
458                 err = copy_from_user(&req, argp,
459                                      sizeof(struct ubi_leb_change_req));
460                 if (err) {
461                         err = -EFAULT;
462                         break;
463                 }
464
465                 if (desc->mode == UBI_READONLY ||
466                     vol->vol_type == UBI_STATIC_VOLUME) {
467                         err = -EROFS;
468                         break;
469                 }
470
471                 /* Validate the request */
472                 err = -EINVAL;
473                 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
474                     req.bytes < 0 || req.lnum >= vol->usable_leb_size)
475                         break;
476                 if (req.dtype != UBI_LONGTERM && req.dtype != UBI_SHORTTERM &&
477                     req.dtype != UBI_UNKNOWN)
478                         break;
479
480                 err = get_exclusive(desc);
481                 if (err < 0)
482                         break;
483
484                 err = ubi_start_leb_change(ubi, vol, &req);
485                 if (req.bytes == 0)
486                         revoke_exclusive(desc, UBI_READWRITE);
487                 break;
488         }
489
490         /* Logical eraseblock erasure command */
491         case UBI_IOCEBER:
492         {
493                 int32_t lnum;
494
495                 err = get_user(lnum, (__user int32_t *)argp);
496                 if (err) {
497                         err = -EFAULT;
498                         break;
499                 }
500
501                 if (desc->mode == UBI_READONLY ||
502                     vol->vol_type == UBI_STATIC_VOLUME) {
503                         err = -EROFS;
504                         break;
505                 }
506
507                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
508                         err = -EINVAL;
509                         break;
510                 }
511
512                 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
513                 err = ubi_eba_unmap_leb(ubi, vol, lnum);
514                 if (err)
515                         break;
516
517                 err = ubi_wl_flush(ubi);
518                 break;
519         }
520
521         /* Logical eraseblock map command */
522         case UBI_IOCEBMAP:
523         {
524                 struct ubi_map_req req;
525
526                 err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
527                 if (err) {
528                         err = -EFAULT;
529                         break;
530                 }
531                 err = ubi_leb_map(desc, req.lnum, req.dtype);
532                 break;
533         }
534
535         /* Logical eraseblock un-map command */
536         case UBI_IOCEBUNMAP:
537         {
538                 int32_t lnum;
539
540                 err = get_user(lnum, (__user int32_t *)argp);
541                 if (err) {
542                         err = -EFAULT;
543                         break;
544                 }
545                 err = ubi_leb_unmap(desc, lnum);
546                 break;
547         }
548
549         /* Check if logical eraseblock is mapped command */
550         case UBI_IOCEBISMAP:
551         {
552                 int32_t lnum;
553
554                 err = get_user(lnum, (__user int32_t *)argp);
555                 if (err) {
556                         err = -EFAULT;
557                         break;
558                 }
559                 err = ubi_is_mapped(desc, lnum);
560                 break;
561         }
562
563         /* Set volume property command */
564         case UBI_IOCSETPROP:
565         {
566                 struct ubi_set_prop_req req;
567
568                 err = copy_from_user(&req, argp,
569                                 sizeof(struct ubi_set_prop_req));
570                 if (err) {
571                         err = -EFAULT;
572                         break;
573                 }
574                 switch (req.property) {
575                 case UBI_PROP_DIRECT_WRITE:
576                         mutex_lock(&ubi->device_mutex);
577                         desc->vol->direct_writes = !!req.value;
578                         mutex_unlock(&ubi->device_mutex);
579                         break;
580                 default:
581                         err = -EINVAL;
582                         break;
583                 }
584                 break;
585         }
586
587         default:
588                 err = -ENOTTY;
589                 break;
590         }
591         return err;
592 }
593
594 /**
595  * verify_mkvol_req - verify volume creation request.
596  * @ubi: UBI device description object
597  * @req: the request to check
598  *
599  * This function zero if the request is correct, and %-EINVAL if not.
600  */
601 static int verify_mkvol_req(const struct ubi_device *ubi,
602                             const struct ubi_mkvol_req *req)
603 {
604         int n, err = -EINVAL;
605
606         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
607             req->name_len < 0)
608                 goto bad;
609
610         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
611             req->vol_id != UBI_VOL_NUM_AUTO)
612                 goto bad;
613
614         if (req->alignment == 0)
615                 goto bad;
616
617         if (req->bytes == 0)
618                 goto bad;
619
620         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
621             req->vol_type != UBI_STATIC_VOLUME)
622                 goto bad;
623
624         if (req->alignment > ubi->leb_size)
625                 goto bad;
626
627         n = req->alignment & (ubi->min_io_size - 1);
628         if (req->alignment != 1 && n)
629                 goto bad;
630
631         if (req->name_len > UBI_VOL_NAME_MAX) {
632                 err = -ENAMETOOLONG;
633                 goto bad;
634         }
635
636         n = strnlen(req->name, req->name_len + 1);
637         if (n != req->name_len)
638                 goto bad;
639
640         return 0;
641
642 bad:
643         dbg_err("bad volume creation request");
644         ubi_dbg_dump_mkvol_req(req);
645         return err;
646 }
647
648 /**
649  * verify_rsvol_req - verify volume re-size request.
650  * @ubi: UBI device description object
651  * @req: the request to check
652  *
653  * This function returns zero if the request is correct, and %-EINVAL if not.
654  */
655 static int verify_rsvol_req(const struct ubi_device *ubi,
656                             const struct ubi_rsvol_req *req)
657 {
658         if (req->bytes <= 0)
659                 return -EINVAL;
660
661         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
662                 return -EINVAL;
663
664         return 0;
665 }
666
667 /**
668  * rename_volumes - rename UBI volumes.
669  * @ubi: UBI device description object
670  * @req: volumes re-name request
671  *
672  * This is a helper function for the volume re-name IOCTL which validates the
673  * the request, opens the volume and calls corresponding volumes management
674  * function. Returns zero in case of success and a negative error code in case
675  * of failure.
676  */
677 static int rename_volumes(struct ubi_device *ubi,
678                           struct ubi_rnvol_req *req)
679 {
680         int i, n, err;
681         struct list_head rename_list;
682         struct ubi_rename_entry *re, *re1;
683
684         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
685                 return -EINVAL;
686
687         if (req->count == 0)
688                 return 0;
689
690         /* Validate volume IDs and names in the request */
691         for (i = 0; i < req->count; i++) {
692                 if (req->ents[i].vol_id < 0 ||
693                     req->ents[i].vol_id >= ubi->vtbl_slots)
694                         return -EINVAL;
695                 if (req->ents[i].name_len < 0)
696                         return -EINVAL;
697                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
698                         return -ENAMETOOLONG;
699                 req->ents[i].name[req->ents[i].name_len] = '\0';
700                 n = strlen(req->ents[i].name);
701                 if (n != req->ents[i].name_len)
702                         err = -EINVAL;
703         }
704
705         /* Make sure volume IDs and names are unique */
706         for (i = 0; i < req->count - 1; i++) {
707                 for (n = i + 1; n < req->count; n++) {
708                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
709                                 dbg_err("duplicated volume id %d",
710                                         req->ents[i].vol_id);
711                                 return -EINVAL;
712                         }
713                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
714                                 dbg_err("duplicated volume name \"%s\"",
715                                         req->ents[i].name);
716                                 return -EINVAL;
717                         }
718                 }
719         }
720
721         /* Create the re-name list */
722         INIT_LIST_HEAD(&rename_list);
723         for (i = 0; i < req->count; i++) {
724                 int vol_id = req->ents[i].vol_id;
725                 int name_len = req->ents[i].name_len;
726                 const char *name = req->ents[i].name;
727
728                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
729                 if (!re) {
730                         err = -ENOMEM;
731                         goto out_free;
732                 }
733
734                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
735                 if (IS_ERR(re->desc)) {
736                         err = PTR_ERR(re->desc);
737                         dbg_err("cannot open volume %d, error %d", vol_id, err);
738                         kfree(re);
739                         goto out_free;
740                 }
741
742                 /* Skip this re-naming if the name does not really change */
743                 if (re->desc->vol->name_len == name_len &&
744                     !memcmp(re->desc->vol->name, name, name_len)) {
745                         ubi_close_volume(re->desc);
746                         kfree(re);
747                         continue;
748                 }
749
750                 re->new_name_len = name_len;
751                 memcpy(re->new_name, name, name_len);
752                 list_add_tail(&re->list, &rename_list);
753                 dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
754                         vol_id, re->desc->vol->name, name);
755         }
756
757         if (list_empty(&rename_list))
758                 return 0;
759
760         /* Find out the volumes which have to be removed */
761         list_for_each_entry(re, &rename_list, list) {
762                 struct ubi_volume_desc *desc;
763                 int no_remove_needed = 0;
764
765                 /*
766                  * Volume @re->vol_id is going to be re-named to
767                  * @re->new_name, while its current name is @name. If a volume
768                  * with name @re->new_name currently exists, it has to be
769                  * removed, unless it is also re-named in the request (@req).
770                  */
771                 list_for_each_entry(re1, &rename_list, list) {
772                         if (re->new_name_len == re1->desc->vol->name_len &&
773                             !memcmp(re->new_name, re1->desc->vol->name,
774                                     re1->desc->vol->name_len)) {
775                                 no_remove_needed = 1;
776                                 break;
777                         }
778                 }
779
780                 if (no_remove_needed)
781                         continue;
782
783                 /*
784                  * It seems we need to remove volume with name @re->new_name,
785                  * if it exists.
786                  */
787                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
788                                           UBI_EXCLUSIVE);
789                 if (IS_ERR(desc)) {
790                         err = PTR_ERR(desc);
791                         if (err == -ENODEV)
792                                 /* Re-naming into a non-existing volume name */
793                                 continue;
794
795                         /* The volume exists but busy, or an error occurred */
796                         dbg_err("cannot open volume \"%s\", error %d",
797                                 re->new_name, err);
798                         goto out_free;
799                 }
800
801                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
802                 if (!re) {
803                         err = -ENOMEM;
804                         ubi_close_volume(desc);
805                         goto out_free;
806                 }
807
808                 re->remove = 1;
809                 re->desc = desc;
810                 list_add(&re->list, &rename_list);
811                 dbg_msg("will remove volume %d, name \"%s\"",
812                         re->desc->vol->vol_id, re->desc->vol->name);
813         }
814
815         mutex_lock(&ubi->device_mutex);
816         err = ubi_rename_volumes(ubi, &rename_list);
817         mutex_unlock(&ubi->device_mutex);
818
819 out_free:
820         list_for_each_entry_safe(re, re1, &rename_list, list) {
821                 ubi_close_volume(re->desc);
822                 list_del(&re->list);
823                 kfree(re);
824         }
825         return err;
826 }
827
828 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
829                            unsigned long arg)
830 {
831         int err = 0;
832         struct ubi_device *ubi;
833         struct ubi_volume_desc *desc;
834         void __user *argp = (void __user *)arg;
835
836         if (!capable(CAP_SYS_RESOURCE))
837                 return -EPERM;
838
839         ubi = ubi_get_by_major(imajor(file->f_mapping->host));
840         if (!ubi)
841                 return -ENODEV;
842
843         switch (cmd) {
844         /* Create volume command */
845         case UBI_IOCMKVOL:
846         {
847                 struct ubi_mkvol_req req;
848
849                 dbg_gen("create volume");
850                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
851                 if (err) {
852                         err = -EFAULT;
853                         break;
854                 }
855
856                 err = verify_mkvol_req(ubi, &req);
857                 if (err)
858                         break;
859
860                 mutex_lock(&ubi->device_mutex);
861                 err = ubi_create_volume(ubi, &req);
862                 mutex_unlock(&ubi->device_mutex);
863                 if (err)
864                         break;
865
866                 err = put_user(req.vol_id, (__user int32_t *)argp);
867                 if (err)
868                         err = -EFAULT;
869
870                 break;
871         }
872
873         /* Remove volume command */
874         case UBI_IOCRMVOL:
875         {
876                 int vol_id;
877
878                 dbg_gen("remove volume");
879                 err = get_user(vol_id, (__user int32_t *)argp);
880                 if (err) {
881                         err = -EFAULT;
882                         break;
883                 }
884
885                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
886                 if (IS_ERR(desc)) {
887                         err = PTR_ERR(desc);
888                         break;
889                 }
890
891                 mutex_lock(&ubi->device_mutex);
892                 err = ubi_remove_volume(desc, 0);
893                 mutex_unlock(&ubi->device_mutex);
894
895                 /*
896                  * The volume is deleted (unless an error occurred), and the
897                  * 'struct ubi_volume' object will be freed when
898                  * 'ubi_close_volume()' will call 'put_device()'.
899                  */
900                 ubi_close_volume(desc);
901                 break;
902         }
903
904         /* Re-size volume command */
905         case UBI_IOCRSVOL:
906         {
907                 int pebs;
908                 struct ubi_rsvol_req req;
909
910                 dbg_gen("re-size volume");
911                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
912                 if (err) {
913                         err = -EFAULT;
914                         break;
915                 }
916
917                 err = verify_rsvol_req(ubi, &req);
918                 if (err)
919                         break;
920
921                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
922                 if (IS_ERR(desc)) {
923                         err = PTR_ERR(desc);
924                         break;
925                 }
926
927                 pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
928                                desc->vol->usable_leb_size);
929
930                 mutex_lock(&ubi->device_mutex);
931                 err = ubi_resize_volume(desc, pebs);
932                 mutex_unlock(&ubi->device_mutex);
933                 ubi_close_volume(desc);
934                 break;
935         }
936
937         /* Re-name volumes command */
938         case UBI_IOCRNVOL:
939         {
940                 struct ubi_rnvol_req *req;
941
942                 dbg_msg("re-name volumes");
943                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
944                 if (!req) {
945                         err = -ENOMEM;
946                         break;
947                 };
948
949                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
950                 if (err) {
951                         err = -EFAULT;
952                         kfree(req);
953                         break;
954                 }
955
956                 err = rename_volumes(ubi, req);
957                 kfree(req);
958                 break;
959         }
960
961         default:
962                 err = -ENOTTY;
963                 break;
964         }
965
966         ubi_put_device(ubi);
967         return err;
968 }
969
970 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
971                             unsigned long arg)
972 {
973         int err = 0;
974         void __user *argp = (void __user *)arg;
975
976         if (!capable(CAP_SYS_RESOURCE))
977                 return -EPERM;
978
979         switch (cmd) {
980         /* Attach an MTD device command */
981         case UBI_IOCATT:
982         {
983                 struct ubi_attach_req req;
984                 struct mtd_info *mtd;
985
986                 dbg_gen("attach MTD device");
987                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
988                 if (err) {
989                         err = -EFAULT;
990                         break;
991                 }
992
993                 if (req.mtd_num < 0 ||
994                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
995                         err = -EINVAL;
996                         break;
997                 }
998
999                 mtd = get_mtd_device(NULL, req.mtd_num);
1000                 if (IS_ERR(mtd)) {
1001                         err = PTR_ERR(mtd);
1002                         break;
1003                 }
1004
1005                 /*
1006                  * Note, further request verification is done by
1007                  * 'ubi_attach_mtd_dev()'.
1008                  */
1009                 mutex_lock(&ubi_devices_mutex);
1010                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
1011                 mutex_unlock(&ubi_devices_mutex);
1012                 if (err < 0)
1013                         put_mtd_device(mtd);
1014                 else
1015                         /* @err contains UBI device number */
1016                         err = put_user(err, (__user int32_t *)argp);
1017
1018                 break;
1019         }
1020
1021         /* Detach an MTD device command */
1022         case UBI_IOCDET:
1023         {
1024                 int ubi_num;
1025
1026                 dbg_gen("dettach MTD device");
1027                 err = get_user(ubi_num, (__user int32_t *)argp);
1028                 if (err) {
1029                         err = -EFAULT;
1030                         break;
1031                 }
1032
1033                 mutex_lock(&ubi_devices_mutex);
1034                 err = ubi_detach_mtd_dev(ubi_num, 0);
1035                 mutex_unlock(&ubi_devices_mutex);
1036                 break;
1037         }
1038
1039         default:
1040                 err = -ENOTTY;
1041                 break;
1042         }
1043
1044         return err;
1045 }
1046
1047 #ifdef CONFIG_COMPAT
1048 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1049                                   unsigned long arg)
1050 {
1051         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1052
1053         return vol_cdev_ioctl(file, cmd, translated_arg);
1054 }
1055
1056 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1057                                   unsigned long arg)
1058 {
1059         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1060
1061         return ubi_cdev_ioctl(file, cmd, translated_arg);
1062 }
1063
1064 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1065                                    unsigned long arg)
1066 {
1067         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1068
1069         return ctrl_cdev_ioctl(file, cmd, translated_arg);
1070 }
1071 #else
1072 #define vol_cdev_compat_ioctl  NULL
1073 #define ubi_cdev_compat_ioctl  NULL
1074 #define ctrl_cdev_compat_ioctl NULL
1075 #endif
1076
1077 /* UBI volume character device operations */
1078 const struct file_operations ubi_vol_cdev_operations = {
1079         .owner          = THIS_MODULE,
1080         .open           = vol_cdev_open,
1081         .release        = vol_cdev_release,
1082         .llseek         = vol_cdev_llseek,
1083         .read           = vol_cdev_read,
1084         .write          = vol_cdev_write,
1085         .fsync          = vol_cdev_fsync,
1086         .unlocked_ioctl = vol_cdev_ioctl,
1087         .compat_ioctl   = vol_cdev_compat_ioctl,
1088 };
1089
1090 /* UBI character device operations */
1091 const struct file_operations ubi_cdev_operations = {
1092         .owner          = THIS_MODULE,
1093         .llseek         = no_llseek,
1094         .unlocked_ioctl = ubi_cdev_ioctl,
1095         .compat_ioctl   = ubi_cdev_compat_ioctl,
1096 };
1097
1098 /* UBI control character device operations */
1099 const struct file_operations ubi_ctrl_cdev_operations = {
1100         .owner          = THIS_MODULE,
1101         .unlocked_ioctl = ctrl_cdev_ioctl,
1102         .compat_ioctl   = ctrl_cdev_compat_ioctl,
1103 };