xref: /linux/drivers/mtd/ubi/cdev.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
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  * @ubi: UBI device description object
52  * @desc: volume descriptor
53  *
54  * This function changes UBI volume open mode to "exclusive". Returns previous
55  * mode value (positive integer) in case of success and a negative error code
56  * in case of failure.
57  */
58 static int get_exclusive(struct ubi_device *ubi, struct ubi_volume_desc *desc)
59 {
60 	int users, err;
61 	struct ubi_volume *vol = desc->vol;
62 
63 	spin_lock(&vol->ubi->volumes_lock);
64 	users = vol->readers + vol->writers + vol->exclusive;
65 	ubi_assert(users > 0);
66 	if (users > 1) {
67 		ubi_err(ubi, "%d users for volume %d", users, vol->vol_id);
68 		err = -EBUSY;
69 	} else {
70 		vol->readers = vol->writers = 0;
71 		vol->exclusive = 1;
72 		err = desc->mode;
73 		desc->mode = UBI_EXCLUSIVE;
74 	}
75 	spin_unlock(&vol->ubi->volumes_lock);
76 
77 	return err;
78 }
79 
80 /**
81  * revoke_exclusive - revoke exclusive mode.
82  * @desc: volume descriptor
83  * @mode: new mode to switch to
84  */
85 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
86 {
87 	struct ubi_volume *vol = desc->vol;
88 
89 	spin_lock(&vol->ubi->volumes_lock);
90 	ubi_assert(vol->readers == 0 && vol->writers == 0);
91 	ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
92 	vol->exclusive = 0;
93 	if (mode == UBI_READONLY)
94 		vol->readers = 1;
95 	else if (mode == UBI_READWRITE)
96 		vol->writers = 1;
97 	else
98 		vol->exclusive = 1;
99 	spin_unlock(&vol->ubi->volumes_lock);
100 
101 	desc->mode = mode;
102 }
103 
104 static int vol_cdev_open(struct inode *inode, struct file *file)
105 {
106 	struct ubi_volume_desc *desc;
107 	int vol_id = iminor(inode) - 1, mode, ubi_num;
108 
109 	ubi_num = ubi_major2num(imajor(inode));
110 	if (ubi_num < 0)
111 		return ubi_num;
112 
113 	if (file->f_mode & FMODE_WRITE)
114 		mode = UBI_READWRITE;
115 	else
116 		mode = UBI_READONLY;
117 
118 	dbg_gen("open device %d, volume %d, mode %d",
119 		ubi_num, vol_id, mode);
120 
121 	desc = ubi_open_volume(ubi_num, vol_id, mode);
122 	if (IS_ERR(desc))
123 		return PTR_ERR(desc);
124 
125 	file->private_data = desc;
126 	return 0;
127 }
128 
129 static int vol_cdev_release(struct inode *inode, struct file *file)
130 {
131 	struct ubi_volume_desc *desc = file->private_data;
132 	struct ubi_volume *vol = desc->vol;
133 
134 	dbg_gen("release device %d, volume %d, mode %d",
135 		vol->ubi->ubi_num, vol->vol_id, desc->mode);
136 
137 	if (vol->updating) {
138 		ubi_warn(vol->ubi, "update of volume %d not finished, volume is damaged",
139 			 vol->vol_id);
140 		ubi_assert(!vol->changing_leb);
141 		vol->updating = 0;
142 		vfree(vol->upd_buf);
143 	} else if (vol->changing_leb) {
144 		dbg_gen("only %lld of %lld bytes received for atomic LEB change for volume %d:%d, cancel",
145 			vol->upd_received, vol->upd_bytes, vol->ubi->ubi_num,
146 			vol->vol_id);
147 		vol->changing_leb = 0;
148 		vfree(vol->upd_buf);
149 	}
150 
151 	ubi_close_volume(desc);
152 	return 0;
153 }
154 
155 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
156 {
157 	struct ubi_volume_desc *desc = file->private_data;
158 	struct ubi_volume *vol = desc->vol;
159 
160 	if (vol->updating) {
161 		/* Update is in progress, seeking is prohibited */
162 		ubi_err(vol->ubi, "updating");
163 		return -EBUSY;
164 	}
165 
166 	return fixed_size_llseek(file, offset, origin, vol->used_bytes);
167 }
168 
169 static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
170 			  int datasync)
171 {
172 	struct ubi_volume_desc *desc = file->private_data;
173 	struct ubi_device *ubi = desc->vol->ubi;
174 	struct inode *inode = file_inode(file);
175 	int err;
176 	mutex_lock(&inode->i_mutex);
177 	err = ubi_sync(ubi->ubi_num);
178 	mutex_unlock(&inode->i_mutex);
179 	return err;
180 }
181 
182 
183 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
184 			     loff_t *offp)
185 {
186 	struct ubi_volume_desc *desc = file->private_data;
187 	struct ubi_volume *vol = desc->vol;
188 	struct ubi_device *ubi = vol->ubi;
189 	int err, lnum, off, len,  tbuf_size;
190 	size_t count_save = count;
191 	void *tbuf;
192 
193 	dbg_gen("read %zd bytes from offset %lld of volume %d",
194 		count, *offp, vol->vol_id);
195 
196 	if (vol->updating) {
197 		ubi_err(vol->ubi, "updating");
198 		return -EBUSY;
199 	}
200 	if (vol->upd_marker) {
201 		ubi_err(vol->ubi, "damaged volume, update marker is set");
202 		return -EBADF;
203 	}
204 	if (*offp == vol->used_bytes || count == 0)
205 		return 0;
206 
207 	if (vol->corrupted)
208 		dbg_gen("read from corrupted volume %d", vol->vol_id);
209 
210 	if (*offp + count > vol->used_bytes)
211 		count_save = count = vol->used_bytes - *offp;
212 
213 	tbuf_size = vol->usable_leb_size;
214 	if (count < tbuf_size)
215 		tbuf_size = ALIGN(count, ubi->min_io_size);
216 	tbuf = vmalloc(tbuf_size);
217 	if (!tbuf)
218 		return -ENOMEM;
219 
220 	len = count > tbuf_size ? tbuf_size : count;
221 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
222 
223 	do {
224 		cond_resched();
225 
226 		if (off + len >= vol->usable_leb_size)
227 			len = vol->usable_leb_size - off;
228 
229 		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
230 		if (err)
231 			break;
232 
233 		off += len;
234 		if (off == vol->usable_leb_size) {
235 			lnum += 1;
236 			off -= vol->usable_leb_size;
237 		}
238 
239 		count -= len;
240 		*offp += len;
241 
242 		err = copy_to_user(buf, tbuf, len);
243 		if (err) {
244 			err = -EFAULT;
245 			break;
246 		}
247 
248 		buf += len;
249 		len = count > tbuf_size ? tbuf_size : count;
250 	} while (count);
251 
252 	vfree(tbuf);
253 	return err ? err : count_save - count;
254 }
255 
256 /*
257  * This function allows to directly write to dynamic UBI volumes, without
258  * issuing the volume update operation.
259  */
260 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
261 				     size_t count, loff_t *offp)
262 {
263 	struct ubi_volume_desc *desc = file->private_data;
264 	struct ubi_volume *vol = desc->vol;
265 	struct ubi_device *ubi = vol->ubi;
266 	int lnum, off, len, tbuf_size, err = 0;
267 	size_t count_save = count;
268 	char *tbuf;
269 
270 	if (!vol->direct_writes)
271 		return -EPERM;
272 
273 	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
274 		count, *offp, vol->vol_id);
275 
276 	if (vol->vol_type == UBI_STATIC_VOLUME)
277 		return -EROFS;
278 
279 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
280 	if (off & (ubi->min_io_size - 1)) {
281 		ubi_err(ubi, "unaligned position");
282 		return -EINVAL;
283 	}
284 
285 	if (*offp + count > vol->used_bytes)
286 		count_save = count = vol->used_bytes - *offp;
287 
288 	/* We can write only in fractions of the minimum I/O unit */
289 	if (count & (ubi->min_io_size - 1)) {
290 		ubi_err(ubi, "unaligned write length");
291 		return -EINVAL;
292 	}
293 
294 	tbuf_size = vol->usable_leb_size;
295 	if (count < tbuf_size)
296 		tbuf_size = ALIGN(count, ubi->min_io_size);
297 	tbuf = vmalloc(tbuf_size);
298 	if (!tbuf)
299 		return -ENOMEM;
300 
301 	len = count > tbuf_size ? tbuf_size : count;
302 
303 	while (count) {
304 		cond_resched();
305 
306 		if (off + len >= vol->usable_leb_size)
307 			len = vol->usable_leb_size - off;
308 
309 		err = copy_from_user(tbuf, buf, len);
310 		if (err) {
311 			err = -EFAULT;
312 			break;
313 		}
314 
315 		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
316 		if (err)
317 			break;
318 
319 		off += len;
320 		if (off == vol->usable_leb_size) {
321 			lnum += 1;
322 			off -= vol->usable_leb_size;
323 		}
324 
325 		count -= len;
326 		*offp += len;
327 		buf += len;
328 		len = count > tbuf_size ? tbuf_size : count;
329 	}
330 
331 	vfree(tbuf);
332 	return err ? err : count_save - count;
333 }
334 
335 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
336 			      size_t count, loff_t *offp)
337 {
338 	int err = 0;
339 	struct ubi_volume_desc *desc = file->private_data;
340 	struct ubi_volume *vol = desc->vol;
341 	struct ubi_device *ubi = vol->ubi;
342 
343 	if (!vol->updating && !vol->changing_leb)
344 		return vol_cdev_direct_write(file, buf, count, offp);
345 
346 	if (vol->updating)
347 		err = ubi_more_update_data(ubi, vol, buf, count);
348 	else
349 		err = ubi_more_leb_change_data(ubi, vol, buf, count);
350 
351 	if (err < 0) {
352 		ubi_err(ubi, "cannot accept more %zd bytes of data, error %d",
353 			count, err);
354 		return err;
355 	}
356 
357 	if (err) {
358 		/*
359 		 * The operation is finished, @err contains number of actually
360 		 * written bytes.
361 		 */
362 		count = err;
363 
364 		if (vol->changing_leb) {
365 			revoke_exclusive(desc, UBI_READWRITE);
366 			return count;
367 		}
368 
369 		err = ubi_check_volume(ubi, vol->vol_id);
370 		if (err < 0)
371 			return err;
372 
373 		if (err) {
374 			ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
375 				 vol->vol_id, ubi->ubi_num);
376 			vol->corrupted = 1;
377 		}
378 		vol->checked = 1;
379 		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
380 		revoke_exclusive(desc, UBI_READWRITE);
381 	}
382 
383 	return count;
384 }
385 
386 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
387 			   unsigned long arg)
388 {
389 	int err = 0;
390 	struct ubi_volume_desc *desc = file->private_data;
391 	struct ubi_volume *vol = desc->vol;
392 	struct ubi_device *ubi = vol->ubi;
393 	void __user *argp = (void __user *)arg;
394 
395 	switch (cmd) {
396 	/* Volume update command */
397 	case UBI_IOCVOLUP:
398 	{
399 		int64_t bytes, rsvd_bytes;
400 
401 		if (!capable(CAP_SYS_RESOURCE)) {
402 			err = -EPERM;
403 			break;
404 		}
405 
406 		err = copy_from_user(&bytes, argp, sizeof(int64_t));
407 		if (err) {
408 			err = -EFAULT;
409 			break;
410 		}
411 
412 		if (desc->mode == UBI_READONLY) {
413 			err = -EROFS;
414 			break;
415 		}
416 
417 		rsvd_bytes = (long long)vol->reserved_pebs *
418 					ubi->leb_size-vol->data_pad;
419 		if (bytes < 0 || bytes > rsvd_bytes) {
420 			err = -EINVAL;
421 			break;
422 		}
423 
424 		err = get_exclusive(ubi, desc);
425 		if (err < 0)
426 			break;
427 
428 		err = ubi_start_update(ubi, vol, bytes);
429 		if (bytes == 0) {
430 			ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
431 			revoke_exclusive(desc, UBI_READWRITE);
432 		}
433 		break;
434 	}
435 
436 	/* Atomic logical eraseblock change command */
437 	case UBI_IOCEBCH:
438 	{
439 		struct ubi_leb_change_req req;
440 
441 		err = copy_from_user(&req, argp,
442 				     sizeof(struct ubi_leb_change_req));
443 		if (err) {
444 			err = -EFAULT;
445 			break;
446 		}
447 
448 		if (desc->mode == UBI_READONLY ||
449 		    vol->vol_type == UBI_STATIC_VOLUME) {
450 			err = -EROFS;
451 			break;
452 		}
453 
454 		/* Validate the request */
455 		err = -EINVAL;
456 		if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
457 		    req.bytes < 0 || req.lnum >= vol->usable_leb_size)
458 			break;
459 
460 		err = get_exclusive(ubi, desc);
461 		if (err < 0)
462 			break;
463 
464 		err = ubi_start_leb_change(ubi, vol, &req);
465 		if (req.bytes == 0)
466 			revoke_exclusive(desc, UBI_READWRITE);
467 		break;
468 	}
469 
470 	/* Logical eraseblock erasure command */
471 	case UBI_IOCEBER:
472 	{
473 		int32_t lnum;
474 
475 		err = get_user(lnum, (__user int32_t *)argp);
476 		if (err) {
477 			err = -EFAULT;
478 			break;
479 		}
480 
481 		if (desc->mode == UBI_READONLY ||
482 		    vol->vol_type == UBI_STATIC_VOLUME) {
483 			err = -EROFS;
484 			break;
485 		}
486 
487 		if (lnum < 0 || lnum >= vol->reserved_pebs) {
488 			err = -EINVAL;
489 			break;
490 		}
491 
492 		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
493 		err = ubi_eba_unmap_leb(ubi, vol, lnum);
494 		if (err)
495 			break;
496 
497 		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
498 		break;
499 	}
500 
501 	/* Logical eraseblock map command */
502 	case UBI_IOCEBMAP:
503 	{
504 		struct ubi_map_req req;
505 
506 		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
507 		if (err) {
508 			err = -EFAULT;
509 			break;
510 		}
511 		err = ubi_leb_map(desc, req.lnum);
512 		break;
513 	}
514 
515 	/* Logical eraseblock un-map command */
516 	case UBI_IOCEBUNMAP:
517 	{
518 		int32_t lnum;
519 
520 		err = get_user(lnum, (__user int32_t *)argp);
521 		if (err) {
522 			err = -EFAULT;
523 			break;
524 		}
525 		err = ubi_leb_unmap(desc, lnum);
526 		break;
527 	}
528 
529 	/* Check if logical eraseblock is mapped command */
530 	case UBI_IOCEBISMAP:
531 	{
532 		int32_t lnum;
533 
534 		err = get_user(lnum, (__user int32_t *)argp);
535 		if (err) {
536 			err = -EFAULT;
537 			break;
538 		}
539 		err = ubi_is_mapped(desc, lnum);
540 		break;
541 	}
542 
543 	/* Set volume property command */
544 	case UBI_IOCSETVOLPROP:
545 	{
546 		struct ubi_set_vol_prop_req req;
547 
548 		err = copy_from_user(&req, argp,
549 				     sizeof(struct ubi_set_vol_prop_req));
550 		if (err) {
551 			err = -EFAULT;
552 			break;
553 		}
554 		switch (req.property) {
555 		case UBI_VOL_PROP_DIRECT_WRITE:
556 			mutex_lock(&ubi->device_mutex);
557 			desc->vol->direct_writes = !!req.value;
558 			mutex_unlock(&ubi->device_mutex);
559 			break;
560 		default:
561 			err = -EINVAL;
562 			break;
563 		}
564 		break;
565 	}
566 
567 	/* Create a R/O block device on top of the UBI volume */
568 	case UBI_IOCVOLCRBLK:
569 	{
570 		struct ubi_volume_info vi;
571 
572 		ubi_get_volume_info(desc, &vi);
573 		err = ubiblock_create(&vi);
574 		break;
575 	}
576 
577 	/* Remove the R/O block device */
578 	case UBI_IOCVOLRMBLK:
579 	{
580 		struct ubi_volume_info vi;
581 
582 		ubi_get_volume_info(desc, &vi);
583 		err = ubiblock_remove(&vi);
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[0] || !req->name_len)
632 		goto bad;
633 
634 	if (req->name_len > UBI_VOL_NAME_MAX) {
635 		err = -ENAMETOOLONG;
636 		goto bad;
637 	}
638 
639 	n = strnlen(req->name, req->name_len + 1);
640 	if (n != req->name_len)
641 		goto bad;
642 
643 	return 0;
644 
645 bad:
646 	ubi_err(ubi, "bad volume creation request");
647 	ubi_dump_mkvol_req(req);
648 	return err;
649 }
650 
651 /**
652  * verify_rsvol_req - verify volume re-size request.
653  * @ubi: UBI device description object
654  * @req: the request to check
655  *
656  * This function returns zero if the request is correct, and %-EINVAL if not.
657  */
658 static int verify_rsvol_req(const struct ubi_device *ubi,
659 			    const struct ubi_rsvol_req *req)
660 {
661 	if (req->bytes <= 0)
662 		return -EINVAL;
663 
664 	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
665 		return -EINVAL;
666 
667 	return 0;
668 }
669 
670 /**
671  * rename_volumes - rename UBI volumes.
672  * @ubi: UBI device description object
673  * @req: volumes re-name request
674  *
675  * This is a helper function for the volume re-name IOCTL which validates the
676  * the request, opens the volume and calls corresponding volumes management
677  * function. Returns zero in case of success and a negative error code in case
678  * of failure.
679  */
680 static int rename_volumes(struct ubi_device *ubi,
681 			  struct ubi_rnvol_req *req)
682 {
683 	int i, n, err;
684 	struct list_head rename_list;
685 	struct ubi_rename_entry *re, *re1;
686 
687 	if (req->count < 0 || req->count > UBI_MAX_RNVOL)
688 		return -EINVAL;
689 
690 	if (req->count == 0)
691 		return 0;
692 
693 	/* Validate volume IDs and names in the request */
694 	for (i = 0; i < req->count; i++) {
695 		if (req->ents[i].vol_id < 0 ||
696 		    req->ents[i].vol_id >= ubi->vtbl_slots)
697 			return -EINVAL;
698 		if (req->ents[i].name_len < 0)
699 			return -EINVAL;
700 		if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
701 			return -ENAMETOOLONG;
702 		req->ents[i].name[req->ents[i].name_len] = '\0';
703 		n = strlen(req->ents[i].name);
704 		if (n != req->ents[i].name_len)
705 			return -EINVAL;
706 	}
707 
708 	/* Make sure volume IDs and names are unique */
709 	for (i = 0; i < req->count - 1; i++) {
710 		for (n = i + 1; n < req->count; n++) {
711 			if (req->ents[i].vol_id == req->ents[n].vol_id) {
712 				ubi_err(ubi, "duplicated volume id %d",
713 					req->ents[i].vol_id);
714 				return -EINVAL;
715 			}
716 			if (!strcmp(req->ents[i].name, req->ents[n].name)) {
717 				ubi_err(ubi, "duplicated volume name \"%s\"",
718 					req->ents[i].name);
719 				return -EINVAL;
720 			}
721 		}
722 	}
723 
724 	/* Create the re-name list */
725 	INIT_LIST_HEAD(&rename_list);
726 	for (i = 0; i < req->count; i++) {
727 		int vol_id = req->ents[i].vol_id;
728 		int name_len = req->ents[i].name_len;
729 		const char *name = req->ents[i].name;
730 
731 		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
732 		if (!re) {
733 			err = -ENOMEM;
734 			goto out_free;
735 		}
736 
737 		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_READWRITE);
738 		if (IS_ERR(re->desc)) {
739 			err = PTR_ERR(re->desc);
740 			ubi_err(ubi, "cannot open volume %d, error %d",
741 				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_gen("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 			ubi_err(ubi, "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_gen("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_gen("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 					 req.max_beb_per1024);
1016 		mutex_unlock(&ubi_devices_mutex);
1017 		if (err < 0)
1018 			put_mtd_device(mtd);
1019 		else
1020 			/* @err contains UBI device number */
1021 			err = put_user(err, (__user int32_t *)argp);
1022 
1023 		break;
1024 	}
1025 
1026 	/* Detach an MTD device command */
1027 	case UBI_IOCDET:
1028 	{
1029 		int ubi_num;
1030 
1031 		dbg_gen("detach MTD device");
1032 		err = get_user(ubi_num, (__user int32_t *)argp);
1033 		if (err) {
1034 			err = -EFAULT;
1035 			break;
1036 		}
1037 
1038 		mutex_lock(&ubi_devices_mutex);
1039 		err = ubi_detach_mtd_dev(ubi_num, 0);
1040 		mutex_unlock(&ubi_devices_mutex);
1041 		break;
1042 	}
1043 
1044 	default:
1045 		err = -ENOTTY;
1046 		break;
1047 	}
1048 
1049 	return err;
1050 }
1051 
1052 #ifdef CONFIG_COMPAT
1053 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1054 				  unsigned long arg)
1055 {
1056 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1057 
1058 	return vol_cdev_ioctl(file, cmd, translated_arg);
1059 }
1060 
1061 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1062 				  unsigned long arg)
1063 {
1064 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1065 
1066 	return ubi_cdev_ioctl(file, cmd, translated_arg);
1067 }
1068 
1069 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1070 				   unsigned long arg)
1071 {
1072 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1073 
1074 	return ctrl_cdev_ioctl(file, cmd, translated_arg);
1075 }
1076 #else
1077 #define vol_cdev_compat_ioctl  NULL
1078 #define ubi_cdev_compat_ioctl  NULL
1079 #define ctrl_cdev_compat_ioctl NULL
1080 #endif
1081 
1082 /* UBI volume character device operations */
1083 const struct file_operations ubi_vol_cdev_operations = {
1084 	.owner          = THIS_MODULE,
1085 	.open           = vol_cdev_open,
1086 	.release        = vol_cdev_release,
1087 	.llseek         = vol_cdev_llseek,
1088 	.read           = vol_cdev_read,
1089 	.write          = vol_cdev_write,
1090 	.fsync		= vol_cdev_fsync,
1091 	.unlocked_ioctl = vol_cdev_ioctl,
1092 	.compat_ioctl   = vol_cdev_compat_ioctl,
1093 };
1094 
1095 /* UBI character device operations */
1096 const struct file_operations ubi_cdev_operations = {
1097 	.owner          = THIS_MODULE,
1098 	.llseek         = no_llseek,
1099 	.unlocked_ioctl = ubi_cdev_ioctl,
1100 	.compat_ioctl   = ubi_cdev_compat_ioctl,
1101 };
1102 
1103 /* UBI control character device operations */
1104 const struct file_operations ubi_ctrl_cdev_operations = {
1105 	.owner          = THIS_MODULE,
1106 	.unlocked_ioctl = ctrl_cdev_ioctl,
1107 	.compat_ioctl   = ctrl_cdev_compat_ioctl,
1108 	.llseek		= no_llseek,
1109 };
1110