bonding: properly stop queuing work when requested
[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/slab.h>
41 #include <linux/ioctl.h>
42 #include <linux/capability.h>
43 #include <linux/uaccess.h>
44 #include <linux/compat.h>
45 #include <linux/math64.h>
46 #include <mtd/ubi-user.h>
47 #include "ubi.h"
48
49 /**
50  * get_exclusive - get exclusive access to an UBI volume.
51  * @desc: volume descriptor
52  *
53  * This function changes UBI volume open mode to "exclusive". Returns previous
54  * mode value (positive integer) in case of success and a negative error code
55  * in case of failure.
56  */
57 static int get_exclusive(struct ubi_volume_desc *desc)
58 {
59         int users, err;
60         struct ubi_volume *vol = desc->vol;
61
62         spin_lock(&vol->ubi->volumes_lock);
63         users = vol->readers + vol->writers + vol->exclusive;
64         ubi_assert(users > 0);
65         if (users > 1) {
66                 dbg_err("%d users for volume %d", users, vol->vol_id);
67                 err = -EBUSY;
68         } else {
69                 vol->readers = vol->writers = 0;
70                 vol->exclusive = 1;
71                 err = desc->mode;
72                 desc->mode = UBI_EXCLUSIVE;
73         }
74         spin_unlock(&vol->ubi->volumes_lock);
75
76         return err;
77 }
78
79 /**
80  * revoke_exclusive - revoke exclusive mode.
81  * @desc: volume descriptor
82  * @mode: new mode to switch to
83  */
84 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
85 {
86         struct ubi_volume *vol = desc->vol;
87
88         spin_lock(&vol->ubi->volumes_lock);
89         ubi_assert(vol->readers == 0 && vol->writers == 0);
90         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
91         vol->exclusive = 0;
92         if (mode == UBI_READONLY)
93                 vol->readers = 1;
94         else if (mode == UBI_READWRITE)
95                 vol->writers = 1;
96         else
97                 vol->exclusive = 1;
98         spin_unlock(&vol->ubi->volumes_lock);
99
100         desc->mode = mode;
101 }
102
103 static int vol_cdev_open(struct inode *inode, struct file *file)
104 {
105         struct ubi_volume_desc *desc;
106         int vol_id = iminor(inode) - 1, mode, ubi_num;
107
108         ubi_num = ubi_major2num(imajor(inode));
109         if (ubi_num < 0)
110                 return ubi_num;
111
112         if (file->f_mode & FMODE_WRITE)
113                 mode = UBI_READWRITE;
114         else
115                 mode = UBI_READONLY;
116
117         dbg_gen("open device %d, volume %d, mode %d",
118                 ubi_num, vol_id, mode);
119
120         desc = ubi_open_volume(ubi_num, vol_id, mode);
121         if (IS_ERR(desc))
122                 return PTR_ERR(desc);
123
124         file->private_data = desc;
125         return 0;
126 }
127
128 static int vol_cdev_release(struct inode *inode, struct file *file)
129 {
130         struct ubi_volume_desc *desc = file->private_data;
131         struct ubi_volume *vol = desc->vol;
132
133         dbg_gen("release device %d, volume %d, mode %d",
134                 vol->ubi->ubi_num, vol->vol_id, desc->mode);
135
136         if (vol->updating) {
137                 ubi_warn("update of volume %d not finished, volume is damaged",
138                          vol->vol_id);
139                 ubi_assert(!vol->changing_leb);
140                 vol->updating = 0;
141                 vfree(vol->upd_buf);
142         } else if (vol->changing_leb) {
143                 dbg_gen("only %lld of %lld bytes received for atomic LEB change"
144                         " for volume %d:%d, cancel", vol->upd_received,
145                         vol->upd_bytes, vol->ubi->ubi_num, vol->vol_id);
146                 vol->changing_leb = 0;
147                 vfree(vol->upd_buf);
148         }
149
150         ubi_close_volume(desc);
151         return 0;
152 }
153
154 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
155 {
156         struct ubi_volume_desc *desc = file->private_data;
157         struct ubi_volume *vol = desc->vol;
158         loff_t new_offset;
159
160         if (vol->updating) {
161                 /* Update is in progress, seeking is prohibited */
162                 dbg_err("updating");
163                 return -EBUSY;
164         }
165
166         switch (origin) {
167         case 0: /* SEEK_SET */
168                 new_offset = offset;
169                 break;
170         case 1: /* SEEK_CUR */
171                 new_offset = file->f_pos + offset;
172                 break;
173         case 2: /* SEEK_END */
174                 new_offset = vol->used_bytes + offset;
175                 break;
176         default:
177                 return -EINVAL;
178         }
179
180         if (new_offset < 0 || new_offset > vol->used_bytes) {
181                 dbg_err("bad seek %lld", new_offset);
182                 return -EINVAL;
183         }
184
185         dbg_gen("seek volume %d, offset %lld, origin %d, new offset %lld",
186                 vol->vol_id, offset, origin, new_offset);
187
188         file->f_pos = new_offset;
189         return new_offset;
190 }
191
192 static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end, int datasync)
193 {
194         struct ubi_volume_desc *desc = file->private_data;
195         struct ubi_device *ubi = desc->vol->ubi;
196         struct inode *inode = file->f_path.dentry->d_inode;
197         int err;
198         mutex_lock(&inode->i_mutex);
199         err = ubi_sync(ubi->ubi_num);
200         mutex_unlock(&inode->i_mutex);
201         return err;
202 }
203
204
205 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
206                              loff_t *offp)
207 {
208         struct ubi_volume_desc *desc = file->private_data;
209         struct ubi_volume *vol = desc->vol;
210         struct ubi_device *ubi = vol->ubi;
211         int err, lnum, off, len,  tbuf_size;
212         size_t count_save = count;
213         void *tbuf;
214
215         dbg_gen("read %zd bytes from offset %lld of volume %d",
216                 count, *offp, vol->vol_id);
217
218         if (vol->updating) {
219                 dbg_err("updating");
220                 return -EBUSY;
221         }
222         if (vol->upd_marker) {
223                 dbg_err("damaged volume, update marker is set");
224                 return -EBADF;
225         }
226         if (*offp == vol->used_bytes || count == 0)
227                 return 0;
228
229         if (vol->corrupted)
230                 dbg_gen("read from corrupted volume %d", vol->vol_id);
231
232         if (*offp + count > vol->used_bytes)
233                 count_save = count = vol->used_bytes - *offp;
234
235         tbuf_size = vol->usable_leb_size;
236         if (count < tbuf_size)
237                 tbuf_size = ALIGN(count, ubi->min_io_size);
238         tbuf = vmalloc(tbuf_size);
239         if (!tbuf)
240                 return -ENOMEM;
241
242         len = count > tbuf_size ? tbuf_size : count;
243         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
244
245         do {
246                 cond_resched();
247
248                 if (off + len >= vol->usable_leb_size)
249                         len = vol->usable_leb_size - off;
250
251                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
252                 if (err)
253                         break;
254
255                 off += len;
256                 if (off == vol->usable_leb_size) {
257                         lnum += 1;
258                         off -= vol->usable_leb_size;
259                 }
260
261                 count -= len;
262                 *offp += len;
263
264                 err = copy_to_user(buf, tbuf, len);
265                 if (err) {
266                         err = -EFAULT;
267                         break;
268                 }
269
270                 buf += len;
271                 len = count > tbuf_size ? tbuf_size : count;
272         } while (count);
273
274         vfree(tbuf);
275         return err ? err : count_save - count;
276 }
277
278 /*
279  * This function allows to directly write to dynamic UBI volumes, without
280  * issuing the volume update operation.
281  */
282 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
283                                      size_t count, loff_t *offp)
284 {
285         struct ubi_volume_desc *desc = file->private_data;
286         struct ubi_volume *vol = desc->vol;
287         struct ubi_device *ubi = vol->ubi;
288         int lnum, off, len, tbuf_size, err = 0;
289         size_t count_save = count;
290         char *tbuf;
291
292         if (!vol->direct_writes)
293                 return -EPERM;
294
295         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
296                 count, *offp, vol->vol_id);
297
298         if (vol->vol_type == UBI_STATIC_VOLUME)
299                 return -EROFS;
300
301         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
302         if (off & (ubi->min_io_size - 1)) {
303                 dbg_err("unaligned position");
304                 return -EINVAL;
305         }
306
307         if (*offp + count > vol->used_bytes)
308                 count_save = count = vol->used_bytes - *offp;
309
310         /* We can write only in fractions of the minimum I/O unit */
311         if (count & (ubi->min_io_size - 1)) {
312                 dbg_err("unaligned write length");
313                 return -EINVAL;
314         }
315
316         tbuf_size = vol->usable_leb_size;
317         if (count < tbuf_size)
318                 tbuf_size = ALIGN(count, ubi->min_io_size);
319         tbuf = vmalloc(tbuf_size);
320         if (!tbuf)
321                 return -ENOMEM;
322
323         len = count > tbuf_size ? tbuf_size : count;
324
325         while (count) {
326                 cond_resched();
327
328                 if (off + len >= vol->usable_leb_size)
329                         len = vol->usable_leb_size - off;
330
331                 err = copy_from_user(tbuf, buf, len);
332                 if (err) {
333                         err = -EFAULT;
334                         break;
335                 }
336
337                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
338                                         UBI_UNKNOWN);
339                 if (err)
340                         break;
341
342                 off += len;
343                 if (off == vol->usable_leb_size) {
344                         lnum += 1;
345                         off -= vol->usable_leb_size;
346                 }
347
348                 count -= len;
349                 *offp += len;
350                 buf += len;
351                 len = count > tbuf_size ? tbuf_size : count;
352         }
353
354         vfree(tbuf);
355         return err ? err : count_save - count;
356 }
357
358 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
359                               size_t count, loff_t *offp)
360 {
361         int err = 0;
362         struct ubi_volume_desc *desc = file->private_data;
363         struct ubi_volume *vol = desc->vol;
364         struct ubi_device *ubi = vol->ubi;
365
366         if (!vol->updating && !vol->changing_leb)
367                 return vol_cdev_direct_write(file, buf, count, offp);
368
369         if (vol->updating)
370                 err = ubi_more_update_data(ubi, vol, buf, count);
371         else
372                 err = ubi_more_leb_change_data(ubi, vol, buf, count);
373
374         if (err < 0) {
375                 ubi_err("cannot accept more %zd bytes of data, error %d",
376                         count, err);
377                 return err;
378         }
379
380         if (err) {
381                 /*
382                  * The operation is finished, @err contains number of actually
383                  * written bytes.
384                  */
385                 count = err;
386
387                 if (vol->changing_leb) {
388                         revoke_exclusive(desc, UBI_READWRITE);
389                         return count;
390                 }
391
392                 err = ubi_check_volume(ubi, vol->vol_id);
393                 if (err < 0)
394                         return err;
395
396                 if (err) {
397                         ubi_warn("volume %d on UBI device %d is corrupted",
398                                  vol->vol_id, ubi->ubi_num);
399                         vol->corrupted = 1;
400                 }
401                 vol->checked = 1;
402                 ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
403                 revoke_exclusive(desc, UBI_READWRITE);
404         }
405
406         return count;
407 }
408
409 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
410                            unsigned long arg)
411 {
412         int err = 0;
413         struct ubi_volume_desc *desc = file->private_data;
414         struct ubi_volume *vol = desc->vol;
415         struct ubi_device *ubi = vol->ubi;
416         void __user *argp = (void __user *)arg;
417
418         switch (cmd) {
419         /* Volume update command */
420         case UBI_IOCVOLUP:
421         {
422                 int64_t bytes, rsvd_bytes;
423
424                 if (!capable(CAP_SYS_RESOURCE)) {
425                         err = -EPERM;
426                         break;
427                 }
428
429                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
430                 if (err) {
431                         err = -EFAULT;
432                         break;
433                 }
434
435                 if (desc->mode == UBI_READONLY) {
436                         err = -EROFS;
437                         break;
438                 }
439
440                 rsvd_bytes = (long long)vol->reserved_pebs *
441                                         ubi->leb_size-vol->data_pad;
442                 if (bytes < 0 || bytes > rsvd_bytes) {
443                         err = -EINVAL;
444                         break;
445                 }
446
447                 err = get_exclusive(desc);
448                 if (err < 0)
449                         break;
450
451                 err = ubi_start_update(ubi, vol, bytes);
452                 if (bytes == 0)
453                         revoke_exclusive(desc, UBI_READWRITE);
454                 break;
455         }
456
457         /* Atomic logical eraseblock change command */
458         case UBI_IOCEBCH:
459         {
460                 struct ubi_leb_change_req req;
461
462                 err = copy_from_user(&req, argp,
463                                      sizeof(struct ubi_leb_change_req));
464                 if (err) {
465                         err = -EFAULT;
466                         break;
467                 }
468
469                 if (desc->mode == UBI_READONLY ||
470                     vol->vol_type == UBI_STATIC_VOLUME) {
471                         err = -EROFS;
472                         break;
473                 }
474
475                 /* Validate the request */
476                 err = -EINVAL;
477                 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
478                     req.bytes < 0 || req.lnum >= vol->usable_leb_size)
479                         break;
480                 if (req.dtype != UBI_LONGTERM && req.dtype != UBI_SHORTTERM &&
481                     req.dtype != UBI_UNKNOWN)
482                         break;
483
484                 err = get_exclusive(desc);
485                 if (err < 0)
486                         break;
487
488                 err = ubi_start_leb_change(ubi, vol, &req);
489                 if (req.bytes == 0)
490                         revoke_exclusive(desc, UBI_READWRITE);
491                 break;
492         }
493
494         /* Logical eraseblock erasure command */
495         case UBI_IOCEBER:
496         {
497                 int32_t lnum;
498
499                 err = get_user(lnum, (__user int32_t *)argp);
500                 if (err) {
501                         err = -EFAULT;
502                         break;
503                 }
504
505                 if (desc->mode == UBI_READONLY ||
506                     vol->vol_type == UBI_STATIC_VOLUME) {
507                         err = -EROFS;
508                         break;
509                 }
510
511                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
512                         err = -EINVAL;
513                         break;
514                 }
515
516                 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
517                 err = ubi_eba_unmap_leb(ubi, vol, lnum);
518                 if (err)
519                         break;
520
521                 err = ubi_wl_flush(ubi);
522                 break;
523         }
524
525         /* Logical eraseblock map command */
526         case UBI_IOCEBMAP:
527         {
528                 struct ubi_map_req req;
529
530                 err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
531                 if (err) {
532                         err = -EFAULT;
533                         break;
534                 }
535                 err = ubi_leb_map(desc, req.lnum, req.dtype);
536                 break;
537         }
538
539         /* Logical eraseblock un-map command */
540         case UBI_IOCEBUNMAP:
541         {
542                 int32_t lnum;
543
544                 err = get_user(lnum, (__user int32_t *)argp);
545                 if (err) {
546                         err = -EFAULT;
547                         break;
548                 }
549                 err = ubi_leb_unmap(desc, lnum);
550                 break;
551         }
552
553         /* Check if logical eraseblock is mapped command */
554         case UBI_IOCEBISMAP:
555         {
556                 int32_t lnum;
557
558                 err = get_user(lnum, (__user int32_t *)argp);
559                 if (err) {
560                         err = -EFAULT;
561                         break;
562                 }
563                 err = ubi_is_mapped(desc, lnum);
564                 break;
565         }
566
567         /* Set volume property command */
568         case UBI_IOCSETVOLPROP:
569         {
570                 struct ubi_set_vol_prop_req req;
571
572                 err = copy_from_user(&req, argp,
573                                      sizeof(struct ubi_set_vol_prop_req));
574                 if (err) {
575                         err = -EFAULT;
576                         break;
577                 }
578                 switch (req.property) {
579                 case UBI_VOL_PROP_DIRECT_WRITE:
580                         mutex_lock(&ubi->device_mutex);
581                         desc->vol->direct_writes = !!req.value;
582                         mutex_unlock(&ubi->device_mutex);
583                         break;
584                 default:
585                         err = -EINVAL;
586                         break;
587                 }
588                 break;
589         }
590
591         default:
592                 err = -ENOTTY;
593                 break;
594         }
595         return err;
596 }
597
598 /**
599  * verify_mkvol_req - verify volume creation request.
600  * @ubi: UBI device description object
601  * @req: the request to check
602  *
603  * This function zero if the request is correct, and %-EINVAL if not.
604  */
605 static int verify_mkvol_req(const struct ubi_device *ubi,
606                             const struct ubi_mkvol_req *req)
607 {
608         int n, err = -EINVAL;
609
610         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
611             req->name_len < 0)
612                 goto bad;
613
614         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
615             req->vol_id != UBI_VOL_NUM_AUTO)
616                 goto bad;
617
618         if (req->alignment == 0)
619                 goto bad;
620
621         if (req->bytes == 0)
622                 goto bad;
623
624         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
625             req->vol_type != UBI_STATIC_VOLUME)
626                 goto bad;
627
628         if (req->alignment > ubi->leb_size)
629                 goto bad;
630
631         n = req->alignment & (ubi->min_io_size - 1);
632         if (req->alignment != 1 && n)
633                 goto bad;
634
635         if (req->name_len > UBI_VOL_NAME_MAX) {
636                 err = -ENAMETOOLONG;
637                 goto bad;
638         }
639
640         n = strnlen(req->name, req->name_len + 1);
641         if (n != req->name_len)
642                 goto bad;
643
644         return 0;
645
646 bad:
647         dbg_err("bad volume creation request");
648         ubi_dbg_dump_mkvol_req(req);
649         return err;
650 }
651
652 /**
653  * verify_rsvol_req - verify volume re-size request.
654  * @ubi: UBI device description object
655  * @req: the request to check
656  *
657  * This function returns zero if the request is correct, and %-EINVAL if not.
658  */
659 static int verify_rsvol_req(const struct ubi_device *ubi,
660                             const struct ubi_rsvol_req *req)
661 {
662         if (req->bytes <= 0)
663                 return -EINVAL;
664
665         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
666                 return -EINVAL;
667
668         return 0;
669 }
670
671 /**
672  * rename_volumes - rename UBI volumes.
673  * @ubi: UBI device description object
674  * @req: volumes re-name request
675  *
676  * This is a helper function for the volume re-name IOCTL which validates the
677  * the request, opens the volume and calls corresponding volumes management
678  * function. Returns zero in case of success and a negative error code in case
679  * of failure.
680  */
681 static int rename_volumes(struct ubi_device *ubi,
682                           struct ubi_rnvol_req *req)
683 {
684         int i, n, err;
685         struct list_head rename_list;
686         struct ubi_rename_entry *re, *re1;
687
688         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
689                 return -EINVAL;
690
691         if (req->count == 0)
692                 return 0;
693
694         /* Validate volume IDs and names in the request */
695         for (i = 0; i < req->count; i++) {
696                 if (req->ents[i].vol_id < 0 ||
697                     req->ents[i].vol_id >= ubi->vtbl_slots)
698                         return -EINVAL;
699                 if (req->ents[i].name_len < 0)
700                         return -EINVAL;
701                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
702                         return -ENAMETOOLONG;
703                 req->ents[i].name[req->ents[i].name_len] = '\0';
704                 n = strlen(req->ents[i].name);
705                 if (n != req->ents[i].name_len)
706                         err = -EINVAL;
707         }
708
709         /* Make sure volume IDs and names are unique */
710         for (i = 0; i < req->count - 1; i++) {
711                 for (n = i + 1; n < req->count; n++) {
712                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
713                                 dbg_err("duplicated volume id %d",
714                                         req->ents[i].vol_id);
715                                 return -EINVAL;
716                         }
717                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
718                                 dbg_err("duplicated volume name \"%s\"",
719                                         req->ents[i].name);
720                                 return -EINVAL;
721                         }
722                 }
723         }
724
725         /* Create the re-name list */
726         INIT_LIST_HEAD(&rename_list);
727         for (i = 0; i < req->count; i++) {
728                 int vol_id = req->ents[i].vol_id;
729                 int name_len = req->ents[i].name_len;
730                 const char *name = req->ents[i].name;
731
732                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
733                 if (!re) {
734                         err = -ENOMEM;
735                         goto out_free;
736                 }
737
738                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
739                 if (IS_ERR(re->desc)) {
740                         err = PTR_ERR(re->desc);
741                         dbg_err("cannot open volume %d, error %d", vol_id, err);
742                         kfree(re);
743                         goto out_free;
744                 }
745
746                 /* Skip this re-naming if the name does not really change */
747                 if (re->desc->vol->name_len == name_len &&
748                     !memcmp(re->desc->vol->name, name, name_len)) {
749                         ubi_close_volume(re->desc);
750                         kfree(re);
751                         continue;
752                 }
753
754                 re->new_name_len = name_len;
755                 memcpy(re->new_name, name, name_len);
756                 list_add_tail(&re->list, &rename_list);
757                 dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
758                         vol_id, re->desc->vol->name, name);
759         }
760
761         if (list_empty(&rename_list))
762                 return 0;
763
764         /* Find out the volumes which have to be removed */
765         list_for_each_entry(re, &rename_list, list) {
766                 struct ubi_volume_desc *desc;
767                 int no_remove_needed = 0;
768
769                 /*
770                  * Volume @re->vol_id is going to be re-named to
771                  * @re->new_name, while its current name is @name. If a volume
772                  * with name @re->new_name currently exists, it has to be
773                  * removed, unless it is also re-named in the request (@req).
774                  */
775                 list_for_each_entry(re1, &rename_list, list) {
776                         if (re->new_name_len == re1->desc->vol->name_len &&
777                             !memcmp(re->new_name, re1->desc->vol->name,
778                                     re1->desc->vol->name_len)) {
779                                 no_remove_needed = 1;
780                                 break;
781                         }
782                 }
783
784                 if (no_remove_needed)
785                         continue;
786
787                 /*
788                  * It seems we need to remove volume with name @re->new_name,
789                  * if it exists.
790                  */
791                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
792                                           UBI_EXCLUSIVE);
793                 if (IS_ERR(desc)) {
794                         err = PTR_ERR(desc);
795                         if (err == -ENODEV)
796                                 /* Re-naming into a non-existing volume name */
797                                 continue;
798
799                         /* The volume exists but busy, or an error occurred */
800                         dbg_err("cannot open volume \"%s\", error %d",
801                                 re->new_name, err);
802                         goto out_free;
803                 }
804
805                 re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
806                 if (!re1) {
807                         err = -ENOMEM;
808                         ubi_close_volume(desc);
809                         goto out_free;
810                 }
811
812                 re1->remove = 1;
813                 re1->desc = desc;
814                 list_add(&re1->list, &rename_list);
815                 dbg_msg("will remove volume %d, name \"%s\"",
816                         re1->desc->vol->vol_id, re1->desc->vol->name);
817         }
818
819         mutex_lock(&ubi->device_mutex);
820         err = ubi_rename_volumes(ubi, &rename_list);
821         mutex_unlock(&ubi->device_mutex);
822
823 out_free:
824         list_for_each_entry_safe(re, re1, &rename_list, list) {
825                 ubi_close_volume(re->desc);
826                 list_del(&re->list);
827                 kfree(re);
828         }
829         return err;
830 }
831
832 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
833                            unsigned long arg)
834 {
835         int err = 0;
836         struct ubi_device *ubi;
837         struct ubi_volume_desc *desc;
838         void __user *argp = (void __user *)arg;
839
840         if (!capable(CAP_SYS_RESOURCE))
841                 return -EPERM;
842
843         ubi = ubi_get_by_major(imajor(file->f_mapping->host));
844         if (!ubi)
845                 return -ENODEV;
846
847         switch (cmd) {
848         /* Create volume command */
849         case UBI_IOCMKVOL:
850         {
851                 struct ubi_mkvol_req req;
852
853                 dbg_gen("create volume");
854                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
855                 if (err) {
856                         err = -EFAULT;
857                         break;
858                 }
859
860                 err = verify_mkvol_req(ubi, &req);
861                 if (err)
862                         break;
863
864                 mutex_lock(&ubi->device_mutex);
865                 err = ubi_create_volume(ubi, &req);
866                 mutex_unlock(&ubi->device_mutex);
867                 if (err)
868                         break;
869
870                 err = put_user(req.vol_id, (__user int32_t *)argp);
871                 if (err)
872                         err = -EFAULT;
873
874                 break;
875         }
876
877         /* Remove volume command */
878         case UBI_IOCRMVOL:
879         {
880                 int vol_id;
881
882                 dbg_gen("remove volume");
883                 err = get_user(vol_id, (__user int32_t *)argp);
884                 if (err) {
885                         err = -EFAULT;
886                         break;
887                 }
888
889                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
890                 if (IS_ERR(desc)) {
891                         err = PTR_ERR(desc);
892                         break;
893                 }
894
895                 mutex_lock(&ubi->device_mutex);
896                 err = ubi_remove_volume(desc, 0);
897                 mutex_unlock(&ubi->device_mutex);
898
899                 /*
900                  * The volume is deleted (unless an error occurred), and the
901                  * 'struct ubi_volume' object will be freed when
902                  * 'ubi_close_volume()' will call 'put_device()'.
903                  */
904                 ubi_close_volume(desc);
905                 break;
906         }
907
908         /* Re-size volume command */
909         case UBI_IOCRSVOL:
910         {
911                 int pebs;
912                 struct ubi_rsvol_req req;
913
914                 dbg_gen("re-size volume");
915                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
916                 if (err) {
917                         err = -EFAULT;
918                         break;
919                 }
920
921                 err = verify_rsvol_req(ubi, &req);
922                 if (err)
923                         break;
924
925                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
926                 if (IS_ERR(desc)) {
927                         err = PTR_ERR(desc);
928                         break;
929                 }
930
931                 pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
932                                desc->vol->usable_leb_size);
933
934                 mutex_lock(&ubi->device_mutex);
935                 err = ubi_resize_volume(desc, pebs);
936                 mutex_unlock(&ubi->device_mutex);
937                 ubi_close_volume(desc);
938                 break;
939         }
940
941         /* Re-name volumes command */
942         case UBI_IOCRNVOL:
943         {
944                 struct ubi_rnvol_req *req;
945
946                 dbg_msg("re-name volumes");
947                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
948                 if (!req) {
949                         err = -ENOMEM;
950                         break;
951                 };
952
953                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
954                 if (err) {
955                         err = -EFAULT;
956                         kfree(req);
957                         break;
958                 }
959
960                 err = rename_volumes(ubi, req);
961                 kfree(req);
962                 break;
963         }
964
965         default:
966                 err = -ENOTTY;
967                 break;
968         }
969
970         ubi_put_device(ubi);
971         return err;
972 }
973
974 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
975                             unsigned long arg)
976 {
977         int err = 0;
978         void __user *argp = (void __user *)arg;
979
980         if (!capable(CAP_SYS_RESOURCE))
981                 return -EPERM;
982
983         switch (cmd) {
984         /* Attach an MTD device command */
985         case UBI_IOCATT:
986         {
987                 struct ubi_attach_req req;
988                 struct mtd_info *mtd;
989
990                 dbg_gen("attach MTD device");
991                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
992                 if (err) {
993                         err = -EFAULT;
994                         break;
995                 }
996
997                 if (req.mtd_num < 0 ||
998                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
999                         err = -EINVAL;
1000                         break;
1001                 }
1002
1003                 mtd = get_mtd_device(NULL, req.mtd_num);
1004                 if (IS_ERR(mtd)) {
1005                         err = PTR_ERR(mtd);
1006                         break;
1007                 }
1008
1009                 /*
1010                  * Note, further request verification is done by
1011                  * 'ubi_attach_mtd_dev()'.
1012                  */
1013                 mutex_lock(&ubi_devices_mutex);
1014                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
1015                 mutex_unlock(&ubi_devices_mutex);
1016                 if (err < 0)
1017                         put_mtd_device(mtd);
1018                 else
1019                         /* @err contains UBI device number */
1020                         err = put_user(err, (__user int32_t *)argp);
1021
1022                 break;
1023         }
1024
1025         /* Detach an MTD device command */
1026         case UBI_IOCDET:
1027         {
1028                 int ubi_num;
1029
1030                 dbg_gen("dettach MTD device");
1031                 err = get_user(ubi_num, (__user int32_t *)argp);
1032                 if (err) {
1033                         err = -EFAULT;
1034                         break;
1035                 }
1036
1037                 mutex_lock(&ubi_devices_mutex);
1038                 err = ubi_detach_mtd_dev(ubi_num, 0);
1039                 mutex_unlock(&ubi_devices_mutex);
1040                 break;
1041         }
1042
1043         default:
1044                 err = -ENOTTY;
1045                 break;
1046         }
1047
1048         return err;
1049 }
1050
1051 #ifdef CONFIG_COMPAT
1052 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1053                                   unsigned long arg)
1054 {
1055         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1056
1057         return vol_cdev_ioctl(file, cmd, translated_arg);
1058 }
1059
1060 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1061                                   unsigned long arg)
1062 {
1063         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1064
1065         return ubi_cdev_ioctl(file, cmd, translated_arg);
1066 }
1067
1068 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1069                                    unsigned long arg)
1070 {
1071         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1072
1073         return ctrl_cdev_ioctl(file, cmd, translated_arg);
1074 }
1075 #else
1076 #define vol_cdev_compat_ioctl  NULL
1077 #define ubi_cdev_compat_ioctl  NULL
1078 #define ctrl_cdev_compat_ioctl NULL
1079 #endif
1080
1081 /* UBI volume character device operations */
1082 const struct file_operations ubi_vol_cdev_operations = {
1083         .owner          = THIS_MODULE,
1084         .open           = vol_cdev_open,
1085         .release        = vol_cdev_release,
1086         .llseek         = vol_cdev_llseek,
1087         .read           = vol_cdev_read,
1088         .write          = vol_cdev_write,
1089         .fsync          = vol_cdev_fsync,
1090         .unlocked_ioctl = vol_cdev_ioctl,
1091         .compat_ioctl   = vol_cdev_compat_ioctl,
1092 };
1093
1094 /* UBI character device operations */
1095 const struct file_operations ubi_cdev_operations = {
1096         .owner          = THIS_MODULE,
1097         .llseek         = no_llseek,
1098         .unlocked_ioctl = ubi_cdev_ioctl,
1099         .compat_ioctl   = ubi_cdev_compat_ioctl,
1100 };
1101
1102 /* UBI control character device operations */
1103 const struct file_operations ubi_ctrl_cdev_operations = {
1104         .owner          = THIS_MODULE,
1105         .unlocked_ioctl = ctrl_cdev_ioctl,
1106         .compat_ioctl   = ctrl_cdev_compat_ioctl,
1107         .llseek         = no_llseek,
1108 };