xref: /openbmc/linux/drivers/mtd/ubi/cdev.c (revision 5b4cb650)
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 + vol->metaonly;
64 	ubi_assert(users > 0);
65 	if (users > 1) {
66 		ubi_err(vol->ubi, "%d users for volume %d", users, vol->vol_id);
67 		err = -EBUSY;
68 	} else {
69 		vol->readers = vol->writers = vol->metaonly = 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 && vol->metaonly == 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 if (mode == UBI_METAONLY)
97 		vol->metaonly = 1;
98 	else
99 		vol->exclusive = 1;
100 	spin_unlock(&vol->ubi->volumes_lock);
101 
102 	desc->mode = mode;
103 }
104 
105 static int vol_cdev_open(struct inode *inode, struct file *file)
106 {
107 	struct ubi_volume_desc *desc;
108 	int vol_id = iminor(inode) - 1, mode, ubi_num;
109 
110 	ubi_num = ubi_major2num(imajor(inode));
111 	if (ubi_num < 0)
112 		return ubi_num;
113 
114 	if (file->f_mode & FMODE_WRITE)
115 		mode = UBI_READWRITE;
116 	else
117 		mode = UBI_READONLY;
118 
119 	dbg_gen("open device %d, volume %d, mode %d",
120 		ubi_num, vol_id, mode);
121 
122 	desc = ubi_open_volume(ubi_num, vol_id, mode);
123 	if (IS_ERR(desc))
124 		return PTR_ERR(desc);
125 
126 	file->private_data = desc;
127 	return 0;
128 }
129 
130 static int vol_cdev_release(struct inode *inode, struct file *file)
131 {
132 	struct ubi_volume_desc *desc = file->private_data;
133 	struct ubi_volume *vol = desc->vol;
134 
135 	dbg_gen("release device %d, volume %d, mode %d",
136 		vol->ubi->ubi_num, vol->vol_id, desc->mode);
137 
138 	if (vol->updating) {
139 		ubi_warn(vol->ubi, "update of volume %d not finished, volume is damaged",
140 			 vol->vol_id);
141 		ubi_assert(!vol->changing_leb);
142 		vol->updating = 0;
143 		vfree(vol->upd_buf);
144 	} else if (vol->changing_leb) {
145 		dbg_gen("only %lld of %lld bytes received for atomic LEB change for volume %d:%d, cancel",
146 			vol->upd_received, vol->upd_bytes, vol->ubi->ubi_num,
147 			vol->vol_id);
148 		vol->changing_leb = 0;
149 		vfree(vol->upd_buf);
150 	}
151 
152 	ubi_close_volume(desc);
153 	return 0;
154 }
155 
156 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
157 {
158 	struct ubi_volume_desc *desc = file->private_data;
159 	struct ubi_volume *vol = desc->vol;
160 
161 	if (vol->updating) {
162 		/* Update is in progress, seeking is prohibited */
163 		ubi_err(vol->ubi, "updating");
164 		return -EBUSY;
165 	}
166 
167 	return fixed_size_llseek(file, offset, origin, vol->used_bytes);
168 }
169 
170 static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
171 			  int datasync)
172 {
173 	struct ubi_volume_desc *desc = file->private_data;
174 	struct ubi_device *ubi = desc->vol->ubi;
175 	struct inode *inode = file_inode(file);
176 	int err;
177 	inode_lock(inode);
178 	err = ubi_sync(ubi->ubi_num);
179 	inode_unlock(inode);
180 	return err;
181 }
182 
183 
184 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
185 			     loff_t *offp)
186 {
187 	struct ubi_volume_desc *desc = file->private_data;
188 	struct ubi_volume *vol = desc->vol;
189 	struct ubi_device *ubi = vol->ubi;
190 	int err, lnum, off, len,  tbuf_size;
191 	size_t count_save = count;
192 	void *tbuf;
193 
194 	dbg_gen("read %zd bytes from offset %lld of volume %d",
195 		count, *offp, vol->vol_id);
196 
197 	if (vol->updating) {
198 		ubi_err(vol->ubi, "updating");
199 		return -EBUSY;
200 	}
201 	if (vol->upd_marker) {
202 		ubi_err(vol->ubi, "damaged volume, update marker is set");
203 		return -EBADF;
204 	}
205 	if (*offp == vol->used_bytes || count == 0)
206 		return 0;
207 
208 	if (vol->corrupted)
209 		dbg_gen("read from corrupted volume %d", vol->vol_id);
210 
211 	if (*offp + count > vol->used_bytes)
212 		count_save = count = vol->used_bytes - *offp;
213 
214 	tbuf_size = vol->usable_leb_size;
215 	if (count < tbuf_size)
216 		tbuf_size = ALIGN(count, ubi->min_io_size);
217 	tbuf = vmalloc(tbuf_size);
218 	if (!tbuf)
219 		return -ENOMEM;
220 
221 	len = count > tbuf_size ? tbuf_size : count;
222 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
223 
224 	do {
225 		cond_resched();
226 
227 		if (off + len >= vol->usable_leb_size)
228 			len = vol->usable_leb_size - off;
229 
230 		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
231 		if (err)
232 			break;
233 
234 		off += len;
235 		if (off == vol->usable_leb_size) {
236 			lnum += 1;
237 			off -= vol->usable_leb_size;
238 		}
239 
240 		count -= len;
241 		*offp += len;
242 
243 		err = copy_to_user(buf, tbuf, len);
244 		if (err) {
245 			err = -EFAULT;
246 			break;
247 		}
248 
249 		buf += len;
250 		len = count > tbuf_size ? tbuf_size : count;
251 	} while (count);
252 
253 	vfree(tbuf);
254 	return err ? err : count_save - count;
255 }
256 
257 /*
258  * This function allows to directly write to dynamic UBI volumes, without
259  * issuing the volume update operation.
260  */
261 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
262 				     size_t count, loff_t *offp)
263 {
264 	struct ubi_volume_desc *desc = file->private_data;
265 	struct ubi_volume *vol = desc->vol;
266 	struct ubi_device *ubi = vol->ubi;
267 	int lnum, off, len, tbuf_size, err = 0;
268 	size_t count_save = count;
269 	char *tbuf;
270 
271 	if (!vol->direct_writes)
272 		return -EPERM;
273 
274 	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
275 		count, *offp, vol->vol_id);
276 
277 	if (vol->vol_type == UBI_STATIC_VOLUME)
278 		return -EROFS;
279 
280 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
281 	if (off & (ubi->min_io_size - 1)) {
282 		ubi_err(ubi, "unaligned position");
283 		return -EINVAL;
284 	}
285 
286 	if (*offp + count > vol->used_bytes)
287 		count_save = count = vol->used_bytes - *offp;
288 
289 	/* We can write only in fractions of the minimum I/O unit */
290 	if (count & (ubi->min_io_size - 1)) {
291 		ubi_err(ubi, "unaligned write length");
292 		return -EINVAL;
293 	}
294 
295 	tbuf_size = vol->usable_leb_size;
296 	if (count < tbuf_size)
297 		tbuf_size = ALIGN(count, ubi->min_io_size);
298 	tbuf = vmalloc(tbuf_size);
299 	if (!tbuf)
300 		return -ENOMEM;
301 
302 	len = count > tbuf_size ? tbuf_size : count;
303 
304 	while (count) {
305 		cond_resched();
306 
307 		if (off + len >= vol->usable_leb_size)
308 			len = vol->usable_leb_size - off;
309 
310 		err = copy_from_user(tbuf, buf, len);
311 		if (err) {
312 			err = -EFAULT;
313 			break;
314 		}
315 
316 		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
317 		if (err)
318 			break;
319 
320 		off += len;
321 		if (off == vol->usable_leb_size) {
322 			lnum += 1;
323 			off -= vol->usable_leb_size;
324 		}
325 
326 		count -= len;
327 		*offp += len;
328 		buf += len;
329 		len = count > tbuf_size ? tbuf_size : count;
330 	}
331 
332 	vfree(tbuf);
333 	return err ? err : count_save - count;
334 }
335 
336 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
337 			      size_t count, loff_t *offp)
338 {
339 	int err = 0;
340 	struct ubi_volume_desc *desc = file->private_data;
341 	struct ubi_volume *vol = desc->vol;
342 	struct ubi_device *ubi = vol->ubi;
343 
344 	if (!vol->updating && !vol->changing_leb)
345 		return vol_cdev_direct_write(file, buf, count, offp);
346 
347 	if (vol->updating)
348 		err = ubi_more_update_data(ubi, vol, buf, count);
349 	else
350 		err = ubi_more_leb_change_data(ubi, vol, buf, count);
351 
352 	if (err < 0) {
353 		ubi_err(ubi, "cannot accept more %zd bytes of data, error %d",
354 			count, err);
355 		return err;
356 	}
357 
358 	if (err) {
359 		/*
360 		 * The operation is finished, @err contains number of actually
361 		 * written bytes.
362 		 */
363 		count = err;
364 
365 		if (vol->changing_leb) {
366 			revoke_exclusive(desc, UBI_READWRITE);
367 			return count;
368 		}
369 
370 		/*
371 		 * We voluntarily do not take into account the skip_check flag
372 		 * as we want to make sure what we wrote was correctly written.
373 		 */
374 		err = ubi_check_volume(ubi, vol->vol_id);
375 		if (err < 0)
376 			return err;
377 
378 		if (err) {
379 			ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
380 				 vol->vol_id, ubi->ubi_num);
381 			vol->corrupted = 1;
382 		}
383 		vol->checked = 1;
384 		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
385 		revoke_exclusive(desc, UBI_READWRITE);
386 	}
387 
388 	return count;
389 }
390 
391 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
392 			   unsigned long arg)
393 {
394 	int err = 0;
395 	struct ubi_volume_desc *desc = file->private_data;
396 	struct ubi_volume *vol = desc->vol;
397 	struct ubi_device *ubi = vol->ubi;
398 	void __user *argp = (void __user *)arg;
399 
400 	switch (cmd) {
401 	/* Volume update command */
402 	case UBI_IOCVOLUP:
403 	{
404 		int64_t bytes, rsvd_bytes;
405 
406 		if (!capable(CAP_SYS_RESOURCE)) {
407 			err = -EPERM;
408 			break;
409 		}
410 
411 		err = copy_from_user(&bytes, argp, sizeof(int64_t));
412 		if (err) {
413 			err = -EFAULT;
414 			break;
415 		}
416 
417 		if (desc->mode == UBI_READONLY) {
418 			err = -EROFS;
419 			break;
420 		}
421 
422 		rsvd_bytes = (long long)vol->reserved_pebs *
423 					vol->usable_leb_size;
424 		if (bytes < 0 || bytes > rsvd_bytes) {
425 			err = -EINVAL;
426 			break;
427 		}
428 
429 		err = get_exclusive(desc);
430 		if (err < 0)
431 			break;
432 
433 		err = ubi_start_update(ubi, vol, bytes);
434 		if (bytes == 0) {
435 			ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
436 			revoke_exclusive(desc, UBI_READWRITE);
437 		}
438 		break;
439 	}
440 
441 	/* Atomic logical eraseblock change command */
442 	case UBI_IOCEBCH:
443 	{
444 		struct ubi_leb_change_req req;
445 
446 		err = copy_from_user(&req, argp,
447 				     sizeof(struct ubi_leb_change_req));
448 		if (err) {
449 			err = -EFAULT;
450 			break;
451 		}
452 
453 		if (desc->mode == UBI_READONLY ||
454 		    vol->vol_type == UBI_STATIC_VOLUME) {
455 			err = -EROFS;
456 			break;
457 		}
458 
459 		/* Validate the request */
460 		err = -EINVAL;
461 		if (!ubi_leb_valid(vol, req.lnum) ||
462 		    req.bytes < 0 || req.bytes > vol->usable_leb_size)
463 			break;
464 
465 		err = get_exclusive(desc);
466 		if (err < 0)
467 			break;
468 
469 		err = ubi_start_leb_change(ubi, vol, &req);
470 		if (req.bytes == 0)
471 			revoke_exclusive(desc, UBI_READWRITE);
472 		break;
473 	}
474 
475 	/* Logical eraseblock erasure command */
476 	case UBI_IOCEBER:
477 	{
478 		int32_t lnum;
479 
480 		err = get_user(lnum, (__user int32_t *)argp);
481 		if (err) {
482 			err = -EFAULT;
483 			break;
484 		}
485 
486 		if (desc->mode == UBI_READONLY ||
487 		    vol->vol_type == UBI_STATIC_VOLUME) {
488 			err = -EROFS;
489 			break;
490 		}
491 
492 		if (!ubi_leb_valid(vol, lnum)) {
493 			err = -EINVAL;
494 			break;
495 		}
496 
497 		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
498 		err = ubi_eba_unmap_leb(ubi, vol, lnum);
499 		if (err)
500 			break;
501 
502 		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
503 		break;
504 	}
505 
506 	/* Logical eraseblock map command */
507 	case UBI_IOCEBMAP:
508 	{
509 		struct ubi_map_req req;
510 
511 		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
512 		if (err) {
513 			err = -EFAULT;
514 			break;
515 		}
516 		err = ubi_leb_map(desc, req.lnum);
517 		break;
518 	}
519 
520 	/* Logical eraseblock un-map command */
521 	case UBI_IOCEBUNMAP:
522 	{
523 		int32_t lnum;
524 
525 		err = get_user(lnum, (__user int32_t *)argp);
526 		if (err) {
527 			err = -EFAULT;
528 			break;
529 		}
530 		err = ubi_leb_unmap(desc, lnum);
531 		break;
532 	}
533 
534 	/* Check if logical eraseblock is mapped command */
535 	case UBI_IOCEBISMAP:
536 	{
537 		int32_t lnum;
538 
539 		err = get_user(lnum, (__user int32_t *)argp);
540 		if (err) {
541 			err = -EFAULT;
542 			break;
543 		}
544 		err = ubi_is_mapped(desc, lnum);
545 		break;
546 	}
547 
548 	/* Set volume property command */
549 	case UBI_IOCSETVOLPROP:
550 	{
551 		struct ubi_set_vol_prop_req req;
552 
553 		err = copy_from_user(&req, argp,
554 				     sizeof(struct ubi_set_vol_prop_req));
555 		if (err) {
556 			err = -EFAULT;
557 			break;
558 		}
559 		switch (req.property) {
560 		case UBI_VOL_PROP_DIRECT_WRITE:
561 			mutex_lock(&ubi->device_mutex);
562 			desc->vol->direct_writes = !!req.value;
563 			mutex_unlock(&ubi->device_mutex);
564 			break;
565 		default:
566 			err = -EINVAL;
567 			break;
568 		}
569 		break;
570 	}
571 
572 	/* Create a R/O block device on top of the UBI volume */
573 	case UBI_IOCVOLCRBLK:
574 	{
575 		struct ubi_volume_info vi;
576 
577 		ubi_get_volume_info(desc, &vi);
578 		err = ubiblock_create(&vi);
579 		break;
580 	}
581 
582 	/* Remove the R/O block device */
583 	case UBI_IOCVOLRMBLK:
584 	{
585 		struct ubi_volume_info vi;
586 
587 		ubi_get_volume_info(desc, &vi);
588 		err = ubiblock_remove(&vi);
589 		break;
590 	}
591 
592 	default:
593 		err = -ENOTTY;
594 		break;
595 	}
596 	return err;
597 }
598 
599 /**
600  * verify_mkvol_req - verify volume creation request.
601  * @ubi: UBI device description object
602  * @req: the request to check
603  *
604  * This function zero if the request is correct, and %-EINVAL if not.
605  */
606 static int verify_mkvol_req(const struct ubi_device *ubi,
607 			    const struct ubi_mkvol_req *req)
608 {
609 	int n, err = -EINVAL;
610 
611 	if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
612 	    req->name_len < 0)
613 		goto bad;
614 
615 	if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
616 	    req->vol_id != UBI_VOL_NUM_AUTO)
617 		goto bad;
618 
619 	if (req->alignment == 0)
620 		goto bad;
621 
622 	if (req->bytes == 0)
623 		goto bad;
624 
625 	if (req->vol_type != UBI_DYNAMIC_VOLUME &&
626 	    req->vol_type != UBI_STATIC_VOLUME)
627 		goto bad;
628 
629 	if (req->flags & ~UBI_VOL_VALID_FLGS)
630 		goto bad;
631 
632 	if (req->flags & UBI_VOL_SKIP_CRC_CHECK_FLG &&
633 	    req->vol_type != UBI_STATIC_VOLUME)
634 		goto bad;
635 
636 	if (req->alignment > ubi->leb_size)
637 		goto bad;
638 
639 	n = req->alignment & (ubi->min_io_size - 1);
640 	if (req->alignment != 1 && n)
641 		goto bad;
642 
643 	if (!req->name[0] || !req->name_len)
644 		goto bad;
645 
646 	if (req->name_len > UBI_VOL_NAME_MAX) {
647 		err = -ENAMETOOLONG;
648 		goto bad;
649 	}
650 
651 	n = strnlen(req->name, req->name_len + 1);
652 	if (n != req->name_len)
653 		goto bad;
654 
655 	return 0;
656 
657 bad:
658 	ubi_err(ubi, "bad volume creation request");
659 	ubi_dump_mkvol_req(req);
660 	return err;
661 }
662 
663 /**
664  * verify_rsvol_req - verify volume re-size request.
665  * @ubi: UBI device description object
666  * @req: the request to check
667  *
668  * This function returns zero if the request is correct, and %-EINVAL if not.
669  */
670 static int verify_rsvol_req(const struct ubi_device *ubi,
671 			    const struct ubi_rsvol_req *req)
672 {
673 	if (req->bytes <= 0)
674 		return -EINVAL;
675 
676 	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
677 		return -EINVAL;
678 
679 	return 0;
680 }
681 
682 /**
683  * rename_volumes - rename UBI volumes.
684  * @ubi: UBI device description object
685  * @req: volumes re-name request
686  *
687  * This is a helper function for the volume re-name IOCTL which validates the
688  * the request, opens the volume and calls corresponding volumes management
689  * function. Returns zero in case of success and a negative error code in case
690  * of failure.
691  */
692 static int rename_volumes(struct ubi_device *ubi,
693 			  struct ubi_rnvol_req *req)
694 {
695 	int i, n, err;
696 	struct list_head rename_list;
697 	struct ubi_rename_entry *re, *re1;
698 
699 	if (req->count < 0 || req->count > UBI_MAX_RNVOL)
700 		return -EINVAL;
701 
702 	if (req->count == 0)
703 		return 0;
704 
705 	/* Validate volume IDs and names in the request */
706 	for (i = 0; i < req->count; i++) {
707 		if (req->ents[i].vol_id < 0 ||
708 		    req->ents[i].vol_id >= ubi->vtbl_slots)
709 			return -EINVAL;
710 		if (req->ents[i].name_len < 0)
711 			return -EINVAL;
712 		if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
713 			return -ENAMETOOLONG;
714 		req->ents[i].name[req->ents[i].name_len] = '\0';
715 		n = strlen(req->ents[i].name);
716 		if (n != req->ents[i].name_len)
717 			return -EINVAL;
718 	}
719 
720 	/* Make sure volume IDs and names are unique */
721 	for (i = 0; i < req->count - 1; i++) {
722 		for (n = i + 1; n < req->count; n++) {
723 			if (req->ents[i].vol_id == req->ents[n].vol_id) {
724 				ubi_err(ubi, "duplicated volume id %d",
725 					req->ents[i].vol_id);
726 				return -EINVAL;
727 			}
728 			if (!strcmp(req->ents[i].name, req->ents[n].name)) {
729 				ubi_err(ubi, "duplicated volume name \"%s\"",
730 					req->ents[i].name);
731 				return -EINVAL;
732 			}
733 		}
734 	}
735 
736 	/* Create the re-name list */
737 	INIT_LIST_HEAD(&rename_list);
738 	for (i = 0; i < req->count; i++) {
739 		int vol_id = req->ents[i].vol_id;
740 		int name_len = req->ents[i].name_len;
741 		const char *name = req->ents[i].name;
742 
743 		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
744 		if (!re) {
745 			err = -ENOMEM;
746 			goto out_free;
747 		}
748 
749 		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_METAONLY);
750 		if (IS_ERR(re->desc)) {
751 			err = PTR_ERR(re->desc);
752 			ubi_err(ubi, "cannot open volume %d, error %d",
753 				vol_id, err);
754 			kfree(re);
755 			goto out_free;
756 		}
757 
758 		/* Skip this re-naming if the name does not really change */
759 		if (re->desc->vol->name_len == name_len &&
760 		    !memcmp(re->desc->vol->name, name, name_len)) {
761 			ubi_close_volume(re->desc);
762 			kfree(re);
763 			continue;
764 		}
765 
766 		re->new_name_len = name_len;
767 		memcpy(re->new_name, name, name_len);
768 		list_add_tail(&re->list, &rename_list);
769 		dbg_gen("will rename volume %d from \"%s\" to \"%s\"",
770 			vol_id, re->desc->vol->name, name);
771 	}
772 
773 	if (list_empty(&rename_list))
774 		return 0;
775 
776 	/* Find out the volumes which have to be removed */
777 	list_for_each_entry(re, &rename_list, list) {
778 		struct ubi_volume_desc *desc;
779 		int no_remove_needed = 0;
780 
781 		/*
782 		 * Volume @re->vol_id is going to be re-named to
783 		 * @re->new_name, while its current name is @name. If a volume
784 		 * with name @re->new_name currently exists, it has to be
785 		 * removed, unless it is also re-named in the request (@req).
786 		 */
787 		list_for_each_entry(re1, &rename_list, list) {
788 			if (re->new_name_len == re1->desc->vol->name_len &&
789 			    !memcmp(re->new_name, re1->desc->vol->name,
790 				    re1->desc->vol->name_len)) {
791 				no_remove_needed = 1;
792 				break;
793 			}
794 		}
795 
796 		if (no_remove_needed)
797 			continue;
798 
799 		/*
800 		 * It seems we need to remove volume with name @re->new_name,
801 		 * if it exists.
802 		 */
803 		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
804 					  UBI_EXCLUSIVE);
805 		if (IS_ERR(desc)) {
806 			err = PTR_ERR(desc);
807 			if (err == -ENODEV)
808 				/* Re-naming into a non-existing volume name */
809 				continue;
810 
811 			/* The volume exists but busy, or an error occurred */
812 			ubi_err(ubi, "cannot open volume \"%s\", error %d",
813 				re->new_name, err);
814 			goto out_free;
815 		}
816 
817 		re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
818 		if (!re1) {
819 			err = -ENOMEM;
820 			ubi_close_volume(desc);
821 			goto out_free;
822 		}
823 
824 		re1->remove = 1;
825 		re1->desc = desc;
826 		list_add(&re1->list, &rename_list);
827 		dbg_gen("will remove volume %d, name \"%s\"",
828 			re1->desc->vol->vol_id, re1->desc->vol->name);
829 	}
830 
831 	mutex_lock(&ubi->device_mutex);
832 	err = ubi_rename_volumes(ubi, &rename_list);
833 	mutex_unlock(&ubi->device_mutex);
834 
835 out_free:
836 	list_for_each_entry_safe(re, re1, &rename_list, list) {
837 		ubi_close_volume(re->desc);
838 		list_del(&re->list);
839 		kfree(re);
840 	}
841 	return err;
842 }
843 
844 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
845 			   unsigned long arg)
846 {
847 	int err = 0;
848 	struct ubi_device *ubi;
849 	struct ubi_volume_desc *desc;
850 	void __user *argp = (void __user *)arg;
851 
852 	if (!capable(CAP_SYS_RESOURCE))
853 		return -EPERM;
854 
855 	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
856 	if (!ubi)
857 		return -ENODEV;
858 
859 	switch (cmd) {
860 	/* Create volume command */
861 	case UBI_IOCMKVOL:
862 	{
863 		struct ubi_mkvol_req req;
864 
865 		dbg_gen("create volume");
866 		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
867 		if (err) {
868 			err = -EFAULT;
869 			break;
870 		}
871 
872 		err = verify_mkvol_req(ubi, &req);
873 		if (err)
874 			break;
875 
876 		mutex_lock(&ubi->device_mutex);
877 		err = ubi_create_volume(ubi, &req);
878 		mutex_unlock(&ubi->device_mutex);
879 		if (err)
880 			break;
881 
882 		err = put_user(req.vol_id, (__user int32_t *)argp);
883 		if (err)
884 			err = -EFAULT;
885 
886 		break;
887 	}
888 
889 	/* Remove volume command */
890 	case UBI_IOCRMVOL:
891 	{
892 		int vol_id;
893 
894 		dbg_gen("remove volume");
895 		err = get_user(vol_id, (__user int32_t *)argp);
896 		if (err) {
897 			err = -EFAULT;
898 			break;
899 		}
900 
901 		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
902 		if (IS_ERR(desc)) {
903 			err = PTR_ERR(desc);
904 			break;
905 		}
906 
907 		mutex_lock(&ubi->device_mutex);
908 		err = ubi_remove_volume(desc, 0);
909 		mutex_unlock(&ubi->device_mutex);
910 
911 		/*
912 		 * The volume is deleted (unless an error occurred), and the
913 		 * 'struct ubi_volume' object will be freed when
914 		 * 'ubi_close_volume()' will call 'put_device()'.
915 		 */
916 		ubi_close_volume(desc);
917 		break;
918 	}
919 
920 	/* Re-size volume command */
921 	case UBI_IOCRSVOL:
922 	{
923 		int pebs;
924 		struct ubi_rsvol_req req;
925 
926 		dbg_gen("re-size volume");
927 		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
928 		if (err) {
929 			err = -EFAULT;
930 			break;
931 		}
932 
933 		err = verify_rsvol_req(ubi, &req);
934 		if (err)
935 			break;
936 
937 		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
938 		if (IS_ERR(desc)) {
939 			err = PTR_ERR(desc);
940 			break;
941 		}
942 
943 		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
944 			       desc->vol->usable_leb_size);
945 
946 		mutex_lock(&ubi->device_mutex);
947 		err = ubi_resize_volume(desc, pebs);
948 		mutex_unlock(&ubi->device_mutex);
949 		ubi_close_volume(desc);
950 		break;
951 	}
952 
953 	/* Re-name volumes command */
954 	case UBI_IOCRNVOL:
955 	{
956 		struct ubi_rnvol_req *req;
957 
958 		dbg_gen("re-name volumes");
959 		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
960 		if (!req) {
961 			err = -ENOMEM;
962 			break;
963 		}
964 
965 		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
966 		if (err) {
967 			err = -EFAULT;
968 			kfree(req);
969 			break;
970 		}
971 
972 		err = rename_volumes(ubi, req);
973 		kfree(req);
974 		break;
975 	}
976 
977 	default:
978 		err = -ENOTTY;
979 		break;
980 	}
981 
982 	ubi_put_device(ubi);
983 	return err;
984 }
985 
986 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
987 			    unsigned long arg)
988 {
989 	int err = 0;
990 	void __user *argp = (void __user *)arg;
991 
992 	if (!capable(CAP_SYS_RESOURCE))
993 		return -EPERM;
994 
995 	switch (cmd) {
996 	/* Attach an MTD device command */
997 	case UBI_IOCATT:
998 	{
999 		struct ubi_attach_req req;
1000 		struct mtd_info *mtd;
1001 
1002 		dbg_gen("attach MTD device");
1003 		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
1004 		if (err) {
1005 			err = -EFAULT;
1006 			break;
1007 		}
1008 
1009 		if (req.mtd_num < 0 ||
1010 		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
1011 			err = -EINVAL;
1012 			break;
1013 		}
1014 
1015 		mtd = get_mtd_device(NULL, req.mtd_num);
1016 		if (IS_ERR(mtd)) {
1017 			err = PTR_ERR(mtd);
1018 			break;
1019 		}
1020 
1021 		/*
1022 		 * Note, further request verification is done by
1023 		 * 'ubi_attach_mtd_dev()'.
1024 		 */
1025 		mutex_lock(&ubi_devices_mutex);
1026 		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
1027 					 req.max_beb_per1024);
1028 		mutex_unlock(&ubi_devices_mutex);
1029 		if (err < 0)
1030 			put_mtd_device(mtd);
1031 		else
1032 			/* @err contains UBI device number */
1033 			err = put_user(err, (__user int32_t *)argp);
1034 
1035 		break;
1036 	}
1037 
1038 	/* Detach an MTD device command */
1039 	case UBI_IOCDET:
1040 	{
1041 		int ubi_num;
1042 
1043 		dbg_gen("detach MTD device");
1044 		err = get_user(ubi_num, (__user int32_t *)argp);
1045 		if (err) {
1046 			err = -EFAULT;
1047 			break;
1048 		}
1049 
1050 		mutex_lock(&ubi_devices_mutex);
1051 		err = ubi_detach_mtd_dev(ubi_num, 0);
1052 		mutex_unlock(&ubi_devices_mutex);
1053 		break;
1054 	}
1055 
1056 	default:
1057 		err = -ENOTTY;
1058 		break;
1059 	}
1060 
1061 	return err;
1062 }
1063 
1064 #ifdef CONFIG_COMPAT
1065 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1066 				  unsigned long arg)
1067 {
1068 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1069 
1070 	return vol_cdev_ioctl(file, cmd, translated_arg);
1071 }
1072 
1073 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1074 				  unsigned long arg)
1075 {
1076 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1077 
1078 	return ubi_cdev_ioctl(file, cmd, translated_arg);
1079 }
1080 
1081 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1082 				   unsigned long arg)
1083 {
1084 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1085 
1086 	return ctrl_cdev_ioctl(file, cmd, translated_arg);
1087 }
1088 #else
1089 #define vol_cdev_compat_ioctl  NULL
1090 #define ubi_cdev_compat_ioctl  NULL
1091 #define ctrl_cdev_compat_ioctl NULL
1092 #endif
1093 
1094 /* UBI volume character device operations */
1095 const struct file_operations ubi_vol_cdev_operations = {
1096 	.owner          = THIS_MODULE,
1097 	.open           = vol_cdev_open,
1098 	.release        = vol_cdev_release,
1099 	.llseek         = vol_cdev_llseek,
1100 	.read           = vol_cdev_read,
1101 	.write          = vol_cdev_write,
1102 	.fsync		= vol_cdev_fsync,
1103 	.unlocked_ioctl = vol_cdev_ioctl,
1104 	.compat_ioctl   = vol_cdev_compat_ioctl,
1105 };
1106 
1107 /* UBI character device operations */
1108 const struct file_operations ubi_cdev_operations = {
1109 	.owner          = THIS_MODULE,
1110 	.llseek         = no_llseek,
1111 	.unlocked_ioctl = ubi_cdev_ioctl,
1112 	.compat_ioctl   = ubi_cdev_compat_ioctl,
1113 };
1114 
1115 /* UBI control character device operations */
1116 const struct file_operations ubi_ctrl_cdev_operations = {
1117 	.owner          = THIS_MODULE,
1118 	.unlocked_ioctl = ctrl_cdev_ioctl,
1119 	.compat_ioctl   = ctrl_cdev_compat_ioctl,
1120 	.llseek		= no_llseek,
1121 };
1122