xref: /linux/drivers/mtd/ubi/cdev.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5)
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, struct dentry *dentry,
193 			  int datasync)
194 {
195 	struct ubi_volume_desc *desc = file->private_data;
196 	struct ubi_device *ubi = desc->vol->ubi;
197 
198 	return ubi_sync(ubi->ubi_num);
199 }
200 
201 
202 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
203 			     loff_t *offp)
204 {
205 	struct ubi_volume_desc *desc = file->private_data;
206 	struct ubi_volume *vol = desc->vol;
207 	struct ubi_device *ubi = vol->ubi;
208 	int err, lnum, off, len,  tbuf_size;
209 	size_t count_save = count;
210 	void *tbuf;
211 
212 	dbg_gen("read %zd bytes from offset %lld of volume %d",
213 		count, *offp, vol->vol_id);
214 
215 	if (vol->updating) {
216 		dbg_err("updating");
217 		return -EBUSY;
218 	}
219 	if (vol->upd_marker) {
220 		dbg_err("damaged volume, update marker is set");
221 		return -EBADF;
222 	}
223 	if (*offp == vol->used_bytes || count == 0)
224 		return 0;
225 
226 	if (vol->corrupted)
227 		dbg_gen("read from corrupted volume %d", vol->vol_id);
228 
229 	if (*offp + count > vol->used_bytes)
230 		count_save = count = vol->used_bytes - *offp;
231 
232 	tbuf_size = vol->usable_leb_size;
233 	if (count < tbuf_size)
234 		tbuf_size = ALIGN(count, ubi->min_io_size);
235 	tbuf = vmalloc(tbuf_size);
236 	if (!tbuf)
237 		return -ENOMEM;
238 
239 	len = count > tbuf_size ? tbuf_size : count;
240 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
241 
242 	do {
243 		cond_resched();
244 
245 		if (off + len >= vol->usable_leb_size)
246 			len = vol->usable_leb_size - off;
247 
248 		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
249 		if (err)
250 			break;
251 
252 		off += len;
253 		if (off == vol->usable_leb_size) {
254 			lnum += 1;
255 			off -= vol->usable_leb_size;
256 		}
257 
258 		count -= len;
259 		*offp += len;
260 
261 		err = copy_to_user(buf, tbuf, len);
262 		if (err) {
263 			err = -EFAULT;
264 			break;
265 		}
266 
267 		buf += len;
268 		len = count > tbuf_size ? tbuf_size : count;
269 	} while (count);
270 
271 	vfree(tbuf);
272 	return err ? err : count_save - count;
273 }
274 
275 /*
276  * This function allows to directly write to dynamic UBI volumes, without
277  * issuing the volume update operation.
278  */
279 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
280 				     size_t count, loff_t *offp)
281 {
282 	struct ubi_volume_desc *desc = file->private_data;
283 	struct ubi_volume *vol = desc->vol;
284 	struct ubi_device *ubi = vol->ubi;
285 	int lnum, off, len, tbuf_size, err = 0;
286 	size_t count_save = count;
287 	char *tbuf;
288 
289 	if (!vol->direct_writes)
290 		return -EPERM;
291 
292 	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
293 		count, *offp, vol->vol_id);
294 
295 	if (vol->vol_type == UBI_STATIC_VOLUME)
296 		return -EROFS;
297 
298 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
299 	if (off & (ubi->min_io_size - 1)) {
300 		dbg_err("unaligned position");
301 		return -EINVAL;
302 	}
303 
304 	if (*offp + count > vol->used_bytes)
305 		count_save = count = vol->used_bytes - *offp;
306 
307 	/* We can write only in fractions of the minimum I/O unit */
308 	if (count & (ubi->min_io_size - 1)) {
309 		dbg_err("unaligned write length");
310 		return -EINVAL;
311 	}
312 
313 	tbuf_size = vol->usable_leb_size;
314 	if (count < tbuf_size)
315 		tbuf_size = ALIGN(count, ubi->min_io_size);
316 	tbuf = vmalloc(tbuf_size);
317 	if (!tbuf)
318 		return -ENOMEM;
319 
320 	len = count > tbuf_size ? tbuf_size : count;
321 
322 	while (count) {
323 		cond_resched();
324 
325 		if (off + len >= vol->usable_leb_size)
326 			len = vol->usable_leb_size - off;
327 
328 		err = copy_from_user(tbuf, buf, len);
329 		if (err) {
330 			err = -EFAULT;
331 			break;
332 		}
333 
334 		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
335 					UBI_UNKNOWN);
336 		if (err)
337 			break;
338 
339 		off += len;
340 		if (off == vol->usable_leb_size) {
341 			lnum += 1;
342 			off -= vol->usable_leb_size;
343 		}
344 
345 		count -= len;
346 		*offp += len;
347 		buf += len;
348 		len = count > tbuf_size ? tbuf_size : count;
349 	}
350 
351 	vfree(tbuf);
352 	return err ? err : count_save - count;
353 }
354 
355 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
356 			      size_t count, loff_t *offp)
357 {
358 	int err = 0;
359 	struct ubi_volume_desc *desc = file->private_data;
360 	struct ubi_volume *vol = desc->vol;
361 	struct ubi_device *ubi = vol->ubi;
362 
363 	if (!vol->updating && !vol->changing_leb)
364 		return vol_cdev_direct_write(file, buf, count, offp);
365 
366 	if (vol->updating)
367 		err = ubi_more_update_data(ubi, vol, buf, count);
368 	else
369 		err = ubi_more_leb_change_data(ubi, vol, buf, count);
370 
371 	if (err < 0) {
372 		ubi_err("cannot accept more %zd bytes of data, error %d",
373 			count, err);
374 		return err;
375 	}
376 
377 	if (err) {
378 		/*
379 		 * The operation is finished, @err contains number of actually
380 		 * written bytes.
381 		 */
382 		count = err;
383 
384 		if (vol->changing_leb) {
385 			revoke_exclusive(desc, UBI_READWRITE);
386 			return count;
387 		}
388 
389 		err = ubi_check_volume(ubi, vol->vol_id);
390 		if (err < 0)
391 			return err;
392 
393 		if (err) {
394 			ubi_warn("volume %d on UBI device %d is corrupted",
395 				 vol->vol_id, ubi->ubi_num);
396 			vol->corrupted = 1;
397 		}
398 		vol->checked = 1;
399 		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
400 		revoke_exclusive(desc, UBI_READWRITE);
401 	}
402 
403 	return count;
404 }
405 
406 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
407 			   unsigned long arg)
408 {
409 	int err = 0;
410 	struct ubi_volume_desc *desc = file->private_data;
411 	struct ubi_volume *vol = desc->vol;
412 	struct ubi_device *ubi = vol->ubi;
413 	void __user *argp = (void __user *)arg;
414 
415 	switch (cmd) {
416 	/* Volume update command */
417 	case UBI_IOCVOLUP:
418 	{
419 		int64_t bytes, rsvd_bytes;
420 
421 		if (!capable(CAP_SYS_RESOURCE)) {
422 			err = -EPERM;
423 			break;
424 		}
425 
426 		err = copy_from_user(&bytes, argp, sizeof(int64_t));
427 		if (err) {
428 			err = -EFAULT;
429 			break;
430 		}
431 
432 		if (desc->mode == UBI_READONLY) {
433 			err = -EROFS;
434 			break;
435 		}
436 
437 		rsvd_bytes = (long long)vol->reserved_pebs *
438 					ubi->leb_size-vol->data_pad;
439 		if (bytes < 0 || bytes > rsvd_bytes) {
440 			err = -EINVAL;
441 			break;
442 		}
443 
444 		err = get_exclusive(desc);
445 		if (err < 0)
446 			break;
447 
448 		err = ubi_start_update(ubi, vol, bytes);
449 		if (bytes == 0)
450 			revoke_exclusive(desc, UBI_READWRITE);
451 		break;
452 	}
453 
454 	/* Atomic logical eraseblock change command */
455 	case UBI_IOCEBCH:
456 	{
457 		struct ubi_leb_change_req req;
458 
459 		err = copy_from_user(&req, argp,
460 				     sizeof(struct ubi_leb_change_req));
461 		if (err) {
462 			err = -EFAULT;
463 			break;
464 		}
465 
466 		if (desc->mode == UBI_READONLY ||
467 		    vol->vol_type == UBI_STATIC_VOLUME) {
468 			err = -EROFS;
469 			break;
470 		}
471 
472 		/* Validate the request */
473 		err = -EINVAL;
474 		if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
475 		    req.bytes < 0 || req.lnum >= vol->usable_leb_size)
476 			break;
477 		if (req.dtype != UBI_LONGTERM && req.dtype != UBI_SHORTTERM &&
478 		    req.dtype != UBI_UNKNOWN)
479 			break;
480 
481 		err = get_exclusive(desc);
482 		if (err < 0)
483 			break;
484 
485 		err = ubi_start_leb_change(ubi, vol, &req);
486 		if (req.bytes == 0)
487 			revoke_exclusive(desc, UBI_READWRITE);
488 		break;
489 	}
490 
491 	/* Logical eraseblock erasure command */
492 	case UBI_IOCEBER:
493 	{
494 		int32_t lnum;
495 
496 		err = get_user(lnum, (__user int32_t *)argp);
497 		if (err) {
498 			err = -EFAULT;
499 			break;
500 		}
501 
502 		if (desc->mode == UBI_READONLY ||
503 		    vol->vol_type == UBI_STATIC_VOLUME) {
504 			err = -EROFS;
505 			break;
506 		}
507 
508 		if (lnum < 0 || lnum >= vol->reserved_pebs) {
509 			err = -EINVAL;
510 			break;
511 		}
512 
513 		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
514 		err = ubi_eba_unmap_leb(ubi, vol, lnum);
515 		if (err)
516 			break;
517 
518 		err = ubi_wl_flush(ubi);
519 		break;
520 	}
521 
522 	/* Logical eraseblock map command */
523 	case UBI_IOCEBMAP:
524 	{
525 		struct ubi_map_req req;
526 
527 		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
528 		if (err) {
529 			err = -EFAULT;
530 			break;
531 		}
532 		err = ubi_leb_map(desc, req.lnum, req.dtype);
533 		break;
534 	}
535 
536 	/* Logical eraseblock un-map command */
537 	case UBI_IOCEBUNMAP:
538 	{
539 		int32_t lnum;
540 
541 		err = get_user(lnum, (__user int32_t *)argp);
542 		if (err) {
543 			err = -EFAULT;
544 			break;
545 		}
546 		err = ubi_leb_unmap(desc, lnum);
547 		break;
548 	}
549 
550 	/* Check if logical eraseblock is mapped command */
551 	case UBI_IOCEBISMAP:
552 	{
553 		int32_t lnum;
554 
555 		err = get_user(lnum, (__user int32_t *)argp);
556 		if (err) {
557 			err = -EFAULT;
558 			break;
559 		}
560 		err = ubi_is_mapped(desc, lnum);
561 		break;
562 	}
563 
564 	/* Set volume property command */
565 	case UBI_IOCSETPROP:
566 	{
567 		struct ubi_set_prop_req req;
568 
569 		err = copy_from_user(&req, argp,
570 				sizeof(struct ubi_set_prop_req));
571 		if (err) {
572 			err = -EFAULT;
573 			break;
574 		}
575 		switch (req.property) {
576 		case UBI_PROP_DIRECT_WRITE:
577 			mutex_lock(&ubi->device_mutex);
578 			desc->vol->direct_writes = !!req.value;
579 			mutex_unlock(&ubi->device_mutex);
580 			break;
581 		default:
582 			err = -EINVAL;
583 			break;
584 		}
585 		break;
586 	}
587 
588 	default:
589 		err = -ENOTTY;
590 		break;
591 	}
592 	return err;
593 }
594 
595 /**
596  * verify_mkvol_req - verify volume creation request.
597  * @ubi: UBI device description object
598  * @req: the request to check
599  *
600  * This function zero if the request is correct, and %-EINVAL if not.
601  */
602 static int verify_mkvol_req(const struct ubi_device *ubi,
603 			    const struct ubi_mkvol_req *req)
604 {
605 	int n, err = -EINVAL;
606 
607 	if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
608 	    req->name_len < 0)
609 		goto bad;
610 
611 	if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
612 	    req->vol_id != UBI_VOL_NUM_AUTO)
613 		goto bad;
614 
615 	if (req->alignment == 0)
616 		goto bad;
617 
618 	if (req->bytes == 0)
619 		goto bad;
620 
621 	if (req->vol_type != UBI_DYNAMIC_VOLUME &&
622 	    req->vol_type != UBI_STATIC_VOLUME)
623 		goto bad;
624 
625 	if (req->alignment > ubi->leb_size)
626 		goto bad;
627 
628 	n = req->alignment & (ubi->min_io_size - 1);
629 	if (req->alignment != 1 && n)
630 		goto bad;
631 
632 	if (req->name_len > UBI_VOL_NAME_MAX) {
633 		err = -ENAMETOOLONG;
634 		goto bad;
635 	}
636 
637 	n = strnlen(req->name, req->name_len + 1);
638 	if (n != req->name_len)
639 		goto bad;
640 
641 	return 0;
642 
643 bad:
644 	dbg_err("bad volume creation request");
645 	ubi_dbg_dump_mkvol_req(req);
646 	return err;
647 }
648 
649 /**
650  * verify_rsvol_req - verify volume re-size request.
651  * @ubi: UBI device description object
652  * @req: the request to check
653  *
654  * This function returns zero if the request is correct, and %-EINVAL if not.
655  */
656 static int verify_rsvol_req(const struct ubi_device *ubi,
657 			    const struct ubi_rsvol_req *req)
658 {
659 	if (req->bytes <= 0)
660 		return -EINVAL;
661 
662 	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
663 		return -EINVAL;
664 
665 	return 0;
666 }
667 
668 /**
669  * rename_volumes - rename UBI volumes.
670  * @ubi: UBI device description object
671  * @req: volumes re-name request
672  *
673  * This is a helper function for the volume re-name IOCTL which validates the
674  * the request, opens the volume and calls corresponding volumes management
675  * function. Returns zero in case of success and a negative error code in case
676  * of failure.
677  */
678 static int rename_volumes(struct ubi_device *ubi,
679 			  struct ubi_rnvol_req *req)
680 {
681 	int i, n, err;
682 	struct list_head rename_list;
683 	struct ubi_rename_entry *re, *re1;
684 
685 	if (req->count < 0 || req->count > UBI_MAX_RNVOL)
686 		return -EINVAL;
687 
688 	if (req->count == 0)
689 		return 0;
690 
691 	/* Validate volume IDs and names in the request */
692 	for (i = 0; i < req->count; i++) {
693 		if (req->ents[i].vol_id < 0 ||
694 		    req->ents[i].vol_id >= ubi->vtbl_slots)
695 			return -EINVAL;
696 		if (req->ents[i].name_len < 0)
697 			return -EINVAL;
698 		if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
699 			return -ENAMETOOLONG;
700 		req->ents[i].name[req->ents[i].name_len] = '\0';
701 		n = strlen(req->ents[i].name);
702 		if (n != req->ents[i].name_len)
703 			err = -EINVAL;
704 	}
705 
706 	/* Make sure volume IDs and names are unique */
707 	for (i = 0; i < req->count - 1; i++) {
708 		for (n = i + 1; n < req->count; n++) {
709 			if (req->ents[i].vol_id == req->ents[n].vol_id) {
710 				dbg_err("duplicated volume id %d",
711 					req->ents[i].vol_id);
712 				return -EINVAL;
713 			}
714 			if (!strcmp(req->ents[i].name, req->ents[n].name)) {
715 				dbg_err("duplicated volume name \"%s\"",
716 					req->ents[i].name);
717 				return -EINVAL;
718 			}
719 		}
720 	}
721 
722 	/* Create the re-name list */
723 	INIT_LIST_HEAD(&rename_list);
724 	for (i = 0; i < req->count; i++) {
725 		int vol_id = req->ents[i].vol_id;
726 		int name_len = req->ents[i].name_len;
727 		const char *name = req->ents[i].name;
728 
729 		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
730 		if (!re) {
731 			err = -ENOMEM;
732 			goto out_free;
733 		}
734 
735 		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
736 		if (IS_ERR(re->desc)) {
737 			err = PTR_ERR(re->desc);
738 			dbg_err("cannot open volume %d, error %d", vol_id, err);
739 			kfree(re);
740 			goto out_free;
741 		}
742 
743 		/* Skip this re-naming if the name does not really change */
744 		if (re->desc->vol->name_len == name_len &&
745 		    !memcmp(re->desc->vol->name, name, name_len)) {
746 			ubi_close_volume(re->desc);
747 			kfree(re);
748 			continue;
749 		}
750 
751 		re->new_name_len = name_len;
752 		memcpy(re->new_name, name, name_len);
753 		list_add_tail(&re->list, &rename_list);
754 		dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
755 			vol_id, re->desc->vol->name, name);
756 	}
757 
758 	if (list_empty(&rename_list))
759 		return 0;
760 
761 	/* Find out the volumes which have to be removed */
762 	list_for_each_entry(re, &rename_list, list) {
763 		struct ubi_volume_desc *desc;
764 		int no_remove_needed = 0;
765 
766 		/*
767 		 * Volume @re->vol_id is going to be re-named to
768 		 * @re->new_name, while its current name is @name. If a volume
769 		 * with name @re->new_name currently exists, it has to be
770 		 * removed, unless it is also re-named in the request (@req).
771 		 */
772 		list_for_each_entry(re1, &rename_list, list) {
773 			if (re->new_name_len == re1->desc->vol->name_len &&
774 			    !memcmp(re->new_name, re1->desc->vol->name,
775 				    re1->desc->vol->name_len)) {
776 				no_remove_needed = 1;
777 				break;
778 			}
779 		}
780 
781 		if (no_remove_needed)
782 			continue;
783 
784 		/*
785 		 * It seems we need to remove volume with name @re->new_name,
786 		 * if it exists.
787 		 */
788 		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
789 					  UBI_EXCLUSIVE);
790 		if (IS_ERR(desc)) {
791 			err = PTR_ERR(desc);
792 			if (err == -ENODEV)
793 				/* Re-naming into a non-existing volume name */
794 				continue;
795 
796 			/* The volume exists but busy, or an error occurred */
797 			dbg_err("cannot open volume \"%s\", error %d",
798 				re->new_name, err);
799 			goto out_free;
800 		}
801 
802 		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
803 		if (!re) {
804 			err = -ENOMEM;
805 			ubi_close_volume(desc);
806 			goto out_free;
807 		}
808 
809 		re->remove = 1;
810 		re->desc = desc;
811 		list_add(&re->list, &rename_list);
812 		dbg_msg("will remove volume %d, name \"%s\"",
813 			re->desc->vol->vol_id, re->desc->vol->name);
814 	}
815 
816 	mutex_lock(&ubi->device_mutex);
817 	err = ubi_rename_volumes(ubi, &rename_list);
818 	mutex_unlock(&ubi->device_mutex);
819 
820 out_free:
821 	list_for_each_entry_safe(re, re1, &rename_list, list) {
822 		ubi_close_volume(re->desc);
823 		list_del(&re->list);
824 		kfree(re);
825 	}
826 	return err;
827 }
828 
829 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
830 			   unsigned long arg)
831 {
832 	int err = 0;
833 	struct ubi_device *ubi;
834 	struct ubi_volume_desc *desc;
835 	void __user *argp = (void __user *)arg;
836 
837 	if (!capable(CAP_SYS_RESOURCE))
838 		return -EPERM;
839 
840 	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
841 	if (!ubi)
842 		return -ENODEV;
843 
844 	switch (cmd) {
845 	/* Create volume command */
846 	case UBI_IOCMKVOL:
847 	{
848 		struct ubi_mkvol_req req;
849 
850 		dbg_gen("create volume");
851 		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
852 		if (err) {
853 			err = -EFAULT;
854 			break;
855 		}
856 
857 		err = verify_mkvol_req(ubi, &req);
858 		if (err)
859 			break;
860 
861 		mutex_lock(&ubi->device_mutex);
862 		err = ubi_create_volume(ubi, &req);
863 		mutex_unlock(&ubi->device_mutex);
864 		if (err)
865 			break;
866 
867 		err = put_user(req.vol_id, (__user int32_t *)argp);
868 		if (err)
869 			err = -EFAULT;
870 
871 		break;
872 	}
873 
874 	/* Remove volume command */
875 	case UBI_IOCRMVOL:
876 	{
877 		int vol_id;
878 
879 		dbg_gen("remove volume");
880 		err = get_user(vol_id, (__user int32_t *)argp);
881 		if (err) {
882 			err = -EFAULT;
883 			break;
884 		}
885 
886 		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
887 		if (IS_ERR(desc)) {
888 			err = PTR_ERR(desc);
889 			break;
890 		}
891 
892 		mutex_lock(&ubi->device_mutex);
893 		err = ubi_remove_volume(desc, 0);
894 		mutex_unlock(&ubi->device_mutex);
895 
896 		/*
897 		 * The volume is deleted (unless an error occurred), and the
898 		 * 'struct ubi_volume' object will be freed when
899 		 * 'ubi_close_volume()' will call 'put_device()'.
900 		 */
901 		ubi_close_volume(desc);
902 		break;
903 	}
904 
905 	/* Re-size volume command */
906 	case UBI_IOCRSVOL:
907 	{
908 		int pebs;
909 		struct ubi_rsvol_req req;
910 
911 		dbg_gen("re-size volume");
912 		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
913 		if (err) {
914 			err = -EFAULT;
915 			break;
916 		}
917 
918 		err = verify_rsvol_req(ubi, &req);
919 		if (err)
920 			break;
921 
922 		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
923 		if (IS_ERR(desc)) {
924 			err = PTR_ERR(desc);
925 			break;
926 		}
927 
928 		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
929 			       desc->vol->usable_leb_size);
930 
931 		mutex_lock(&ubi->device_mutex);
932 		err = ubi_resize_volume(desc, pebs);
933 		mutex_unlock(&ubi->device_mutex);
934 		ubi_close_volume(desc);
935 		break;
936 	}
937 
938 	/* Re-name volumes command */
939 	case UBI_IOCRNVOL:
940 	{
941 		struct ubi_rnvol_req *req;
942 
943 		dbg_msg("re-name volumes");
944 		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
945 		if (!req) {
946 			err = -ENOMEM;
947 			break;
948 		};
949 
950 		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
951 		if (err) {
952 			err = -EFAULT;
953 			kfree(req);
954 			break;
955 		}
956 
957 		err = rename_volumes(ubi, req);
958 		kfree(req);
959 		break;
960 	}
961 
962 	default:
963 		err = -ENOTTY;
964 		break;
965 	}
966 
967 	ubi_put_device(ubi);
968 	return err;
969 }
970 
971 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
972 			    unsigned long arg)
973 {
974 	int err = 0;
975 	void __user *argp = (void __user *)arg;
976 
977 	if (!capable(CAP_SYS_RESOURCE))
978 		return -EPERM;
979 
980 	switch (cmd) {
981 	/* Attach an MTD device command */
982 	case UBI_IOCATT:
983 	{
984 		struct ubi_attach_req req;
985 		struct mtd_info *mtd;
986 
987 		dbg_gen("attach MTD device");
988 		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
989 		if (err) {
990 			err = -EFAULT;
991 			break;
992 		}
993 
994 		if (req.mtd_num < 0 ||
995 		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
996 			err = -EINVAL;
997 			break;
998 		}
999 
1000 		mtd = get_mtd_device(NULL, req.mtd_num);
1001 		if (IS_ERR(mtd)) {
1002 			err = PTR_ERR(mtd);
1003 			break;
1004 		}
1005 
1006 		/*
1007 		 * Note, further request verification is done by
1008 		 * 'ubi_attach_mtd_dev()'.
1009 		 */
1010 		mutex_lock(&ubi_devices_mutex);
1011 		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
1012 		mutex_unlock(&ubi_devices_mutex);
1013 		if (err < 0)
1014 			put_mtd_device(mtd);
1015 		else
1016 			/* @err contains UBI device number */
1017 			err = put_user(err, (__user int32_t *)argp);
1018 
1019 		break;
1020 	}
1021 
1022 	/* Detach an MTD device command */
1023 	case UBI_IOCDET:
1024 	{
1025 		int ubi_num;
1026 
1027 		dbg_gen("dettach MTD device");
1028 		err = get_user(ubi_num, (__user int32_t *)argp);
1029 		if (err) {
1030 			err = -EFAULT;
1031 			break;
1032 		}
1033 
1034 		mutex_lock(&ubi_devices_mutex);
1035 		err = ubi_detach_mtd_dev(ubi_num, 0);
1036 		mutex_unlock(&ubi_devices_mutex);
1037 		break;
1038 	}
1039 
1040 	default:
1041 		err = -ENOTTY;
1042 		break;
1043 	}
1044 
1045 	return err;
1046 }
1047 
1048 #ifdef CONFIG_COMPAT
1049 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1050 				  unsigned long arg)
1051 {
1052 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1053 
1054 	return vol_cdev_ioctl(file, cmd, translated_arg);
1055 }
1056 
1057 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1058 				  unsigned long arg)
1059 {
1060 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1061 
1062 	return ubi_cdev_ioctl(file, cmd, translated_arg);
1063 }
1064 
1065 static long ctrl_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 ctrl_cdev_ioctl(file, cmd, translated_arg);
1071 }
1072 #else
1073 #define vol_cdev_compat_ioctl  NULL
1074 #define ubi_cdev_compat_ioctl  NULL
1075 #define ctrl_cdev_compat_ioctl NULL
1076 #endif
1077 
1078 /* UBI volume character device operations */
1079 const struct file_operations ubi_vol_cdev_operations = {
1080 	.owner          = THIS_MODULE,
1081 	.open           = vol_cdev_open,
1082 	.release        = vol_cdev_release,
1083 	.llseek         = vol_cdev_llseek,
1084 	.read           = vol_cdev_read,
1085 	.write          = vol_cdev_write,
1086 	.fsync		= vol_cdev_fsync,
1087 	.unlocked_ioctl = vol_cdev_ioctl,
1088 	.compat_ioctl   = vol_cdev_compat_ioctl,
1089 };
1090 
1091 /* UBI character device operations */
1092 const struct file_operations ubi_cdev_operations = {
1093 	.owner          = THIS_MODULE,
1094 	.llseek         = no_llseek,
1095 	.unlocked_ioctl = ubi_cdev_ioctl,
1096 	.compat_ioctl   = ubi_cdev_compat_ioctl,
1097 };
1098 
1099 /* UBI control character device operations */
1100 const struct file_operations ubi_ctrl_cdev_operations = {
1101 	.owner          = THIS_MODULE,
1102 	.unlocked_ioctl = ctrl_cdev_ioctl,
1103 	.compat_ioctl   = ctrl_cdev_compat_ioctl,
1104 };
1105