xref: /openbmc/linux/drivers/mtd/ubi/cdev.c (revision 8b235f2f)
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 	mutex_lock(&inode->i_mutex);
178 	err = ubi_sync(ubi->ubi_num);
179 	mutex_unlock(&inode->i_mutex);
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 		err = ubi_check_volume(ubi, vol->vol_id);
371 		if (err < 0)
372 			return err;
373 
374 		if (err) {
375 			ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
376 				 vol->vol_id, ubi->ubi_num);
377 			vol->corrupted = 1;
378 		}
379 		vol->checked = 1;
380 		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
381 		revoke_exclusive(desc, UBI_READWRITE);
382 	}
383 
384 	return count;
385 }
386 
387 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
388 			   unsigned long arg)
389 {
390 	int err = 0;
391 	struct ubi_volume_desc *desc = file->private_data;
392 	struct ubi_volume *vol = desc->vol;
393 	struct ubi_device *ubi = vol->ubi;
394 	void __user *argp = (void __user *)arg;
395 
396 	switch (cmd) {
397 	/* Volume update command */
398 	case UBI_IOCVOLUP:
399 	{
400 		int64_t bytes, rsvd_bytes;
401 
402 		if (!capable(CAP_SYS_RESOURCE)) {
403 			err = -EPERM;
404 			break;
405 		}
406 
407 		err = copy_from_user(&bytes, argp, sizeof(int64_t));
408 		if (err) {
409 			err = -EFAULT;
410 			break;
411 		}
412 
413 		if (desc->mode == UBI_READONLY) {
414 			err = -EROFS;
415 			break;
416 		}
417 
418 		rsvd_bytes = (long long)vol->reserved_pebs *
419 					ubi->leb_size-vol->data_pad;
420 		if (bytes < 0 || bytes > rsvd_bytes) {
421 			err = -EINVAL;
422 			break;
423 		}
424 
425 		err = get_exclusive(desc);
426 		if (err < 0)
427 			break;
428 
429 		err = ubi_start_update(ubi, vol, bytes);
430 		if (bytes == 0) {
431 			ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
432 			revoke_exclusive(desc, UBI_READWRITE);
433 		}
434 		break;
435 	}
436 
437 	/* Atomic logical eraseblock change command */
438 	case UBI_IOCEBCH:
439 	{
440 		struct ubi_leb_change_req req;
441 
442 		err = copy_from_user(&req, argp,
443 				     sizeof(struct ubi_leb_change_req));
444 		if (err) {
445 			err = -EFAULT;
446 			break;
447 		}
448 
449 		if (desc->mode == UBI_READONLY ||
450 		    vol->vol_type == UBI_STATIC_VOLUME) {
451 			err = -EROFS;
452 			break;
453 		}
454 
455 		/* Validate the request */
456 		err = -EINVAL;
457 		if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
458 		    req.bytes < 0 || req.bytes > vol->usable_leb_size)
459 			break;
460 
461 		err = get_exclusive(desc);
462 		if (err < 0)
463 			break;
464 
465 		err = ubi_start_leb_change(ubi, vol, &req);
466 		if (req.bytes == 0)
467 			revoke_exclusive(desc, UBI_READWRITE);
468 		break;
469 	}
470 
471 	/* Logical eraseblock erasure command */
472 	case UBI_IOCEBER:
473 	{
474 		int32_t lnum;
475 
476 		err = get_user(lnum, (__user int32_t *)argp);
477 		if (err) {
478 			err = -EFAULT;
479 			break;
480 		}
481 
482 		if (desc->mode == UBI_READONLY ||
483 		    vol->vol_type == UBI_STATIC_VOLUME) {
484 			err = -EROFS;
485 			break;
486 		}
487 
488 		if (lnum < 0 || lnum >= vol->reserved_pebs) {
489 			err = -EINVAL;
490 			break;
491 		}
492 
493 		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
494 		err = ubi_eba_unmap_leb(ubi, vol, lnum);
495 		if (err)
496 			break;
497 
498 		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
499 		break;
500 	}
501 
502 	/* Logical eraseblock map command */
503 	case UBI_IOCEBMAP:
504 	{
505 		struct ubi_map_req req;
506 
507 		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
508 		if (err) {
509 			err = -EFAULT;
510 			break;
511 		}
512 		err = ubi_leb_map(desc, req.lnum);
513 		break;
514 	}
515 
516 	/* Logical eraseblock un-map command */
517 	case UBI_IOCEBUNMAP:
518 	{
519 		int32_t lnum;
520 
521 		err = get_user(lnum, (__user int32_t *)argp);
522 		if (err) {
523 			err = -EFAULT;
524 			break;
525 		}
526 		err = ubi_leb_unmap(desc, lnum);
527 		break;
528 	}
529 
530 	/* Check if logical eraseblock is mapped command */
531 	case UBI_IOCEBISMAP:
532 	{
533 		int32_t lnum;
534 
535 		err = get_user(lnum, (__user int32_t *)argp);
536 		if (err) {
537 			err = -EFAULT;
538 			break;
539 		}
540 		err = ubi_is_mapped(desc, lnum);
541 		break;
542 	}
543 
544 	/* Set volume property command */
545 	case UBI_IOCSETVOLPROP:
546 	{
547 		struct ubi_set_vol_prop_req req;
548 
549 		err = copy_from_user(&req, argp,
550 				     sizeof(struct ubi_set_vol_prop_req));
551 		if (err) {
552 			err = -EFAULT;
553 			break;
554 		}
555 		switch (req.property) {
556 		case UBI_VOL_PROP_DIRECT_WRITE:
557 			mutex_lock(&ubi->device_mutex);
558 			desc->vol->direct_writes = !!req.value;
559 			mutex_unlock(&ubi->device_mutex);
560 			break;
561 		default:
562 			err = -EINVAL;
563 			break;
564 		}
565 		break;
566 	}
567 
568 	/* Create a R/O block device on top of the UBI volume */
569 	case UBI_IOCVOLCRBLK:
570 	{
571 		struct ubi_volume_info vi;
572 
573 		ubi_get_volume_info(desc, &vi);
574 		err = ubiblock_create(&vi);
575 		break;
576 	}
577 
578 	/* Remove the R/O block device */
579 	case UBI_IOCVOLRMBLK:
580 	{
581 		struct ubi_volume_info vi;
582 
583 		ubi_get_volume_info(desc, &vi);
584 		err = ubiblock_remove(&vi);
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[0] || !req->name_len)
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 	ubi_err(ubi, "bad volume creation request");
648 	ubi_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 			return -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 				ubi_err(ubi, "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 				ubi_err(ubi, "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_METAONLY);
739 		if (IS_ERR(re->desc)) {
740 			err = PTR_ERR(re->desc);
741 			ubi_err(ubi, "cannot open volume %d, error %d",
742 				vol_id, err);
743 			kfree(re);
744 			goto out_free;
745 		}
746 
747 		/* Skip this re-naming if the name does not really change */
748 		if (re->desc->vol->name_len == name_len &&
749 		    !memcmp(re->desc->vol->name, name, name_len)) {
750 			ubi_close_volume(re->desc);
751 			kfree(re);
752 			continue;
753 		}
754 
755 		re->new_name_len = name_len;
756 		memcpy(re->new_name, name, name_len);
757 		list_add_tail(&re->list, &rename_list);
758 		dbg_gen("will rename volume %d from \"%s\" to \"%s\"",
759 			vol_id, re->desc->vol->name, name);
760 	}
761 
762 	if (list_empty(&rename_list))
763 		return 0;
764 
765 	/* Find out the volumes which have to be removed */
766 	list_for_each_entry(re, &rename_list, list) {
767 		struct ubi_volume_desc *desc;
768 		int no_remove_needed = 0;
769 
770 		/*
771 		 * Volume @re->vol_id is going to be re-named to
772 		 * @re->new_name, while its current name is @name. If a volume
773 		 * with name @re->new_name currently exists, it has to be
774 		 * removed, unless it is also re-named in the request (@req).
775 		 */
776 		list_for_each_entry(re1, &rename_list, list) {
777 			if (re->new_name_len == re1->desc->vol->name_len &&
778 			    !memcmp(re->new_name, re1->desc->vol->name,
779 				    re1->desc->vol->name_len)) {
780 				no_remove_needed = 1;
781 				break;
782 			}
783 		}
784 
785 		if (no_remove_needed)
786 			continue;
787 
788 		/*
789 		 * It seems we need to remove volume with name @re->new_name,
790 		 * if it exists.
791 		 */
792 		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
793 					  UBI_EXCLUSIVE);
794 		if (IS_ERR(desc)) {
795 			err = PTR_ERR(desc);
796 			if (err == -ENODEV)
797 				/* Re-naming into a non-existing volume name */
798 				continue;
799 
800 			/* The volume exists but busy, or an error occurred */
801 			ubi_err(ubi, "cannot open volume \"%s\", error %d",
802 				re->new_name, err);
803 			goto out_free;
804 		}
805 
806 		re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
807 		if (!re1) {
808 			err = -ENOMEM;
809 			ubi_close_volume(desc);
810 			goto out_free;
811 		}
812 
813 		re1->remove = 1;
814 		re1->desc = desc;
815 		list_add(&re1->list, &rename_list);
816 		dbg_gen("will remove volume %d, name \"%s\"",
817 			re1->desc->vol->vol_id, re1->desc->vol->name);
818 	}
819 
820 	mutex_lock(&ubi->device_mutex);
821 	err = ubi_rename_volumes(ubi, &rename_list);
822 	mutex_unlock(&ubi->device_mutex);
823 
824 out_free:
825 	list_for_each_entry_safe(re, re1, &rename_list, list) {
826 		ubi_close_volume(re->desc);
827 		list_del(&re->list);
828 		kfree(re);
829 	}
830 	return err;
831 }
832 
833 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
834 			   unsigned long arg)
835 {
836 	int err = 0;
837 	struct ubi_device *ubi;
838 	struct ubi_volume_desc *desc;
839 	void __user *argp = (void __user *)arg;
840 
841 	if (!capable(CAP_SYS_RESOURCE))
842 		return -EPERM;
843 
844 	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
845 	if (!ubi)
846 		return -ENODEV;
847 
848 	switch (cmd) {
849 	/* Create volume command */
850 	case UBI_IOCMKVOL:
851 	{
852 		struct ubi_mkvol_req req;
853 
854 		dbg_gen("create volume");
855 		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
856 		if (err) {
857 			err = -EFAULT;
858 			break;
859 		}
860 
861 		err = verify_mkvol_req(ubi, &req);
862 		if (err)
863 			break;
864 
865 		mutex_lock(&ubi->device_mutex);
866 		err = ubi_create_volume(ubi, &req);
867 		mutex_unlock(&ubi->device_mutex);
868 		if (err)
869 			break;
870 
871 		err = put_user(req.vol_id, (__user int32_t *)argp);
872 		if (err)
873 			err = -EFAULT;
874 
875 		break;
876 	}
877 
878 	/* Remove volume command */
879 	case UBI_IOCRMVOL:
880 	{
881 		int vol_id;
882 
883 		dbg_gen("remove volume");
884 		err = get_user(vol_id, (__user int32_t *)argp);
885 		if (err) {
886 			err = -EFAULT;
887 			break;
888 		}
889 
890 		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
891 		if (IS_ERR(desc)) {
892 			err = PTR_ERR(desc);
893 			break;
894 		}
895 
896 		mutex_lock(&ubi->device_mutex);
897 		err = ubi_remove_volume(desc, 0);
898 		mutex_unlock(&ubi->device_mutex);
899 
900 		/*
901 		 * The volume is deleted (unless an error occurred), and the
902 		 * 'struct ubi_volume' object will be freed when
903 		 * 'ubi_close_volume()' will call 'put_device()'.
904 		 */
905 		ubi_close_volume(desc);
906 		break;
907 	}
908 
909 	/* Re-size volume command */
910 	case UBI_IOCRSVOL:
911 	{
912 		int pebs;
913 		struct ubi_rsvol_req req;
914 
915 		dbg_gen("re-size volume");
916 		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
917 		if (err) {
918 			err = -EFAULT;
919 			break;
920 		}
921 
922 		err = verify_rsvol_req(ubi, &req);
923 		if (err)
924 			break;
925 
926 		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
927 		if (IS_ERR(desc)) {
928 			err = PTR_ERR(desc);
929 			break;
930 		}
931 
932 		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
933 			       desc->vol->usable_leb_size);
934 
935 		mutex_lock(&ubi->device_mutex);
936 		err = ubi_resize_volume(desc, pebs);
937 		mutex_unlock(&ubi->device_mutex);
938 		ubi_close_volume(desc);
939 		break;
940 	}
941 
942 	/* Re-name volumes command */
943 	case UBI_IOCRNVOL:
944 	{
945 		struct ubi_rnvol_req *req;
946 
947 		dbg_gen("re-name volumes");
948 		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
949 		if (!req) {
950 			err = -ENOMEM;
951 			break;
952 		};
953 
954 		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
955 		if (err) {
956 			err = -EFAULT;
957 			kfree(req);
958 			break;
959 		}
960 
961 		err = rename_volumes(ubi, req);
962 		kfree(req);
963 		break;
964 	}
965 
966 	default:
967 		err = -ENOTTY;
968 		break;
969 	}
970 
971 	ubi_put_device(ubi);
972 	return err;
973 }
974 
975 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
976 			    unsigned long arg)
977 {
978 	int err = 0;
979 	void __user *argp = (void __user *)arg;
980 
981 	if (!capable(CAP_SYS_RESOURCE))
982 		return -EPERM;
983 
984 	switch (cmd) {
985 	/* Attach an MTD device command */
986 	case UBI_IOCATT:
987 	{
988 		struct ubi_attach_req req;
989 		struct mtd_info *mtd;
990 
991 		dbg_gen("attach MTD device");
992 		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
993 		if (err) {
994 			err = -EFAULT;
995 			break;
996 		}
997 
998 		if (req.mtd_num < 0 ||
999 		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
1000 			err = -EINVAL;
1001 			break;
1002 		}
1003 
1004 		mtd = get_mtd_device(NULL, req.mtd_num);
1005 		if (IS_ERR(mtd)) {
1006 			err = PTR_ERR(mtd);
1007 			break;
1008 		}
1009 
1010 		/*
1011 		 * Note, further request verification is done by
1012 		 * 'ubi_attach_mtd_dev()'.
1013 		 */
1014 		mutex_lock(&ubi_devices_mutex);
1015 		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
1016 					 req.max_beb_per1024);
1017 		mutex_unlock(&ubi_devices_mutex);
1018 		if (err < 0)
1019 			put_mtd_device(mtd);
1020 		else
1021 			/* @err contains UBI device number */
1022 			err = put_user(err, (__user int32_t *)argp);
1023 
1024 		break;
1025 	}
1026 
1027 	/* Detach an MTD device command */
1028 	case UBI_IOCDET:
1029 	{
1030 		int ubi_num;
1031 
1032 		dbg_gen("detach MTD device");
1033 		err = get_user(ubi_num, (__user int32_t *)argp);
1034 		if (err) {
1035 			err = -EFAULT;
1036 			break;
1037 		}
1038 
1039 		mutex_lock(&ubi_devices_mutex);
1040 		err = ubi_detach_mtd_dev(ubi_num, 0);
1041 		mutex_unlock(&ubi_devices_mutex);
1042 		break;
1043 	}
1044 
1045 	default:
1046 		err = -ENOTTY;
1047 		break;
1048 	}
1049 
1050 	return err;
1051 }
1052 
1053 #ifdef CONFIG_COMPAT
1054 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1055 				  unsigned long arg)
1056 {
1057 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1058 
1059 	return vol_cdev_ioctl(file, cmd, translated_arg);
1060 }
1061 
1062 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1063 				  unsigned long arg)
1064 {
1065 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1066 
1067 	return ubi_cdev_ioctl(file, cmd, translated_arg);
1068 }
1069 
1070 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1071 				   unsigned long arg)
1072 {
1073 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1074 
1075 	return ctrl_cdev_ioctl(file, cmd, translated_arg);
1076 }
1077 #else
1078 #define vol_cdev_compat_ioctl  NULL
1079 #define ubi_cdev_compat_ioctl  NULL
1080 #define ctrl_cdev_compat_ioctl NULL
1081 #endif
1082 
1083 /* UBI volume character device operations */
1084 const struct file_operations ubi_vol_cdev_operations = {
1085 	.owner          = THIS_MODULE,
1086 	.open           = vol_cdev_open,
1087 	.release        = vol_cdev_release,
1088 	.llseek         = vol_cdev_llseek,
1089 	.read           = vol_cdev_read,
1090 	.write          = vol_cdev_write,
1091 	.fsync		= vol_cdev_fsync,
1092 	.unlocked_ioctl = vol_cdev_ioctl,
1093 	.compat_ioctl   = vol_cdev_compat_ioctl,
1094 };
1095 
1096 /* UBI character device operations */
1097 const struct file_operations ubi_cdev_operations = {
1098 	.owner          = THIS_MODULE,
1099 	.llseek         = no_llseek,
1100 	.unlocked_ioctl = ubi_cdev_ioctl,
1101 	.compat_ioctl   = ubi_cdev_compat_ioctl,
1102 };
1103 
1104 /* UBI control character device operations */
1105 const struct file_operations ubi_ctrl_cdev_operations = {
1106 	.owner          = THIS_MODULE,
1107 	.unlocked_ioctl = ctrl_cdev_ioctl,
1108 	.compat_ioctl   = ctrl_cdev_compat_ioctl,
1109 	.llseek		= no_llseek,
1110 };
1111