xref: /linux/drivers/mtd/ubi/cdev.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
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 		ubi_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 		ubi_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 		ubi_err("bad seek %lld", new_offset);
182 		return -EINVAL;
183 	}
184 
185 	dbg_gen("seek volume %d, offset %lld, origin %d, new offset %lld",
186 		vol->vol_id, offset, origin, new_offset);
187 
188 	file->f_pos = new_offset;
189 	return new_offset;
190 }
191 
192 static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end, int datasync)
193 {
194 	struct ubi_volume_desc *desc = file->private_data;
195 	struct ubi_device *ubi = desc->vol->ubi;
196 	struct inode *inode = file->f_path.dentry->d_inode;
197 	int err;
198 	mutex_lock(&inode->i_mutex);
199 	err = ubi_sync(ubi->ubi_num);
200 	mutex_unlock(&inode->i_mutex);
201 	return err;
202 }
203 
204 
205 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
206 			     loff_t *offp)
207 {
208 	struct ubi_volume_desc *desc = file->private_data;
209 	struct ubi_volume *vol = desc->vol;
210 	struct ubi_device *ubi = vol->ubi;
211 	int err, lnum, off, len,  tbuf_size;
212 	size_t count_save = count;
213 	void *tbuf;
214 
215 	dbg_gen("read %zd bytes from offset %lld of volume %d",
216 		count, *offp, vol->vol_id);
217 
218 	if (vol->updating) {
219 		ubi_err("updating");
220 		return -EBUSY;
221 	}
222 	if (vol->upd_marker) {
223 		ubi_err("damaged volume, update marker is set");
224 		return -EBADF;
225 	}
226 	if (*offp == vol->used_bytes || count == 0)
227 		return 0;
228 
229 	if (vol->corrupted)
230 		dbg_gen("read from corrupted volume %d", vol->vol_id);
231 
232 	if (*offp + count > vol->used_bytes)
233 		count_save = count = vol->used_bytes - *offp;
234 
235 	tbuf_size = vol->usable_leb_size;
236 	if (count < tbuf_size)
237 		tbuf_size = ALIGN(count, ubi->min_io_size);
238 	tbuf = vmalloc(tbuf_size);
239 	if (!tbuf)
240 		return -ENOMEM;
241 
242 	len = count > tbuf_size ? tbuf_size : count;
243 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
244 
245 	do {
246 		cond_resched();
247 
248 		if (off + len >= vol->usable_leb_size)
249 			len = vol->usable_leb_size - off;
250 
251 		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
252 		if (err)
253 			break;
254 
255 		off += len;
256 		if (off == vol->usable_leb_size) {
257 			lnum += 1;
258 			off -= vol->usable_leb_size;
259 		}
260 
261 		count -= len;
262 		*offp += len;
263 
264 		err = copy_to_user(buf, tbuf, len);
265 		if (err) {
266 			err = -EFAULT;
267 			break;
268 		}
269 
270 		buf += len;
271 		len = count > tbuf_size ? tbuf_size : count;
272 	} while (count);
273 
274 	vfree(tbuf);
275 	return err ? err : count_save - count;
276 }
277 
278 /*
279  * This function allows to directly write to dynamic UBI volumes, without
280  * issuing the volume update operation.
281  */
282 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
283 				     size_t count, loff_t *offp)
284 {
285 	struct ubi_volume_desc *desc = file->private_data;
286 	struct ubi_volume *vol = desc->vol;
287 	struct ubi_device *ubi = vol->ubi;
288 	int lnum, off, len, tbuf_size, err = 0;
289 	size_t count_save = count;
290 	char *tbuf;
291 
292 	if (!vol->direct_writes)
293 		return -EPERM;
294 
295 	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
296 		count, *offp, vol->vol_id);
297 
298 	if (vol->vol_type == UBI_STATIC_VOLUME)
299 		return -EROFS;
300 
301 	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
302 	if (off & (ubi->min_io_size - 1)) {
303 		ubi_err("unaligned position");
304 		return -EINVAL;
305 	}
306 
307 	if (*offp + count > vol->used_bytes)
308 		count_save = count = vol->used_bytes - *offp;
309 
310 	/* We can write only in fractions of the minimum I/O unit */
311 	if (count & (ubi->min_io_size - 1)) {
312 		ubi_err("unaligned write length");
313 		return -EINVAL;
314 	}
315 
316 	tbuf_size = vol->usable_leb_size;
317 	if (count < tbuf_size)
318 		tbuf_size = ALIGN(count, ubi->min_io_size);
319 	tbuf = vmalloc(tbuf_size);
320 	if (!tbuf)
321 		return -ENOMEM;
322 
323 	len = count > tbuf_size ? tbuf_size : count;
324 
325 	while (count) {
326 		cond_resched();
327 
328 		if (off + len >= vol->usable_leb_size)
329 			len = vol->usable_leb_size - off;
330 
331 		err = copy_from_user(tbuf, buf, len);
332 		if (err) {
333 			err = -EFAULT;
334 			break;
335 		}
336 
337 		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
338 		if (err)
339 			break;
340 
341 		off += len;
342 		if (off == vol->usable_leb_size) {
343 			lnum += 1;
344 			off -= vol->usable_leb_size;
345 		}
346 
347 		count -= len;
348 		*offp += len;
349 		buf += len;
350 		len = count > tbuf_size ? tbuf_size : count;
351 	}
352 
353 	vfree(tbuf);
354 	return err ? err : count_save - count;
355 }
356 
357 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
358 			      size_t count, loff_t *offp)
359 {
360 	int err = 0;
361 	struct ubi_volume_desc *desc = file->private_data;
362 	struct ubi_volume *vol = desc->vol;
363 	struct ubi_device *ubi = vol->ubi;
364 
365 	if (!vol->updating && !vol->changing_leb)
366 		return vol_cdev_direct_write(file, buf, count, offp);
367 
368 	if (vol->updating)
369 		err = ubi_more_update_data(ubi, vol, buf, count);
370 	else
371 		err = ubi_more_leb_change_data(ubi, vol, buf, count);
372 
373 	if (err < 0) {
374 		ubi_err("cannot accept more %zd bytes of data, error %d",
375 			count, err);
376 		return err;
377 	}
378 
379 	if (err) {
380 		/*
381 		 * The operation is finished, @err contains number of actually
382 		 * written bytes.
383 		 */
384 		count = err;
385 
386 		if (vol->changing_leb) {
387 			revoke_exclusive(desc, UBI_READWRITE);
388 			return count;
389 		}
390 
391 		err = ubi_check_volume(ubi, vol->vol_id);
392 		if (err < 0)
393 			return err;
394 
395 		if (err) {
396 			ubi_warn("volume %d on UBI device %d is corrupted",
397 				 vol->vol_id, ubi->ubi_num);
398 			vol->corrupted = 1;
399 		}
400 		vol->checked = 1;
401 		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
402 		revoke_exclusive(desc, UBI_READWRITE);
403 	}
404 
405 	return count;
406 }
407 
408 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
409 			   unsigned long arg)
410 {
411 	int err = 0;
412 	struct ubi_volume_desc *desc = file->private_data;
413 	struct ubi_volume *vol = desc->vol;
414 	struct ubi_device *ubi = vol->ubi;
415 	void __user *argp = (void __user *)arg;
416 
417 	switch (cmd) {
418 	/* Volume update command */
419 	case UBI_IOCVOLUP:
420 	{
421 		int64_t bytes, rsvd_bytes;
422 
423 		if (!capable(CAP_SYS_RESOURCE)) {
424 			err = -EPERM;
425 			break;
426 		}
427 
428 		err = copy_from_user(&bytes, argp, sizeof(int64_t));
429 		if (err) {
430 			err = -EFAULT;
431 			break;
432 		}
433 
434 		if (desc->mode == UBI_READONLY) {
435 			err = -EROFS;
436 			break;
437 		}
438 
439 		rsvd_bytes = (long long)vol->reserved_pebs *
440 					ubi->leb_size-vol->data_pad;
441 		if (bytes < 0 || bytes > rsvd_bytes) {
442 			err = -EINVAL;
443 			break;
444 		}
445 
446 		err = get_exclusive(desc);
447 		if (err < 0)
448 			break;
449 
450 		err = ubi_start_update(ubi, vol, bytes);
451 		if (bytes == 0)
452 			revoke_exclusive(desc, UBI_READWRITE);
453 		break;
454 	}
455 
456 	/* Atomic logical eraseblock change command */
457 	case UBI_IOCEBCH:
458 	{
459 		struct ubi_leb_change_req req;
460 
461 		err = copy_from_user(&req, argp,
462 				     sizeof(struct ubi_leb_change_req));
463 		if (err) {
464 			err = -EFAULT;
465 			break;
466 		}
467 
468 		if (desc->mode == UBI_READONLY ||
469 		    vol->vol_type == UBI_STATIC_VOLUME) {
470 			err = -EROFS;
471 			break;
472 		}
473 
474 		/* Validate the request */
475 		err = -EINVAL;
476 		if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
477 		    req.bytes < 0 || req.lnum >= vol->usable_leb_size)
478 			break;
479 
480 		err = get_exclusive(desc);
481 		if (err < 0)
482 			break;
483 
484 		err = ubi_start_leb_change(ubi, vol, &req);
485 		if (req.bytes == 0)
486 			revoke_exclusive(desc, UBI_READWRITE);
487 		break;
488 	}
489 
490 	/* Logical eraseblock erasure command */
491 	case UBI_IOCEBER:
492 	{
493 		int32_t lnum;
494 
495 		err = get_user(lnum, (__user int32_t *)argp);
496 		if (err) {
497 			err = -EFAULT;
498 			break;
499 		}
500 
501 		if (desc->mode == UBI_READONLY ||
502 		    vol->vol_type == UBI_STATIC_VOLUME) {
503 			err = -EROFS;
504 			break;
505 		}
506 
507 		if (lnum < 0 || lnum >= vol->reserved_pebs) {
508 			err = -EINVAL;
509 			break;
510 		}
511 
512 		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
513 		err = ubi_eba_unmap_leb(ubi, vol, lnum);
514 		if (err)
515 			break;
516 
517 		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
518 		break;
519 	}
520 
521 	/* Logical eraseblock map command */
522 	case UBI_IOCEBMAP:
523 	{
524 		struct ubi_map_req req;
525 
526 		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
527 		if (err) {
528 			err = -EFAULT;
529 			break;
530 		}
531 		err = ubi_leb_map(desc, req.lnum);
532 		break;
533 	}
534 
535 	/* Logical eraseblock un-map command */
536 	case UBI_IOCEBUNMAP:
537 	{
538 		int32_t lnum;
539 
540 		err = get_user(lnum, (__user int32_t *)argp);
541 		if (err) {
542 			err = -EFAULT;
543 			break;
544 		}
545 		err = ubi_leb_unmap(desc, lnum);
546 		break;
547 	}
548 
549 	/* Check if logical eraseblock is mapped command */
550 	case UBI_IOCEBISMAP:
551 	{
552 		int32_t lnum;
553 
554 		err = get_user(lnum, (__user int32_t *)argp);
555 		if (err) {
556 			err = -EFAULT;
557 			break;
558 		}
559 		err = ubi_is_mapped(desc, lnum);
560 		break;
561 	}
562 
563 	/* Set volume property command */
564 	case UBI_IOCSETVOLPROP:
565 	{
566 		struct ubi_set_vol_prop_req req;
567 
568 		err = copy_from_user(&req, argp,
569 				     sizeof(struct ubi_set_vol_prop_req));
570 		if (err) {
571 			err = -EFAULT;
572 			break;
573 		}
574 		switch (req.property) {
575 		case UBI_VOL_PROP_DIRECT_WRITE:
576 			mutex_lock(&ubi->device_mutex);
577 			desc->vol->direct_writes = !!req.value;
578 			mutex_unlock(&ubi->device_mutex);
579 			break;
580 		default:
581 			err = -EINVAL;
582 			break;
583 		}
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("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 			err = -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("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("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_EXCLUSIVE);
738 		if (IS_ERR(re->desc)) {
739 			err = PTR_ERR(re->desc);
740 			ubi_err("cannot open volume %d, error %d", vol_id, err);
741 			kfree(re);
742 			goto out_free;
743 		}
744 
745 		/* Skip this re-naming if the name does not really change */
746 		if (re->desc->vol->name_len == name_len &&
747 		    !memcmp(re->desc->vol->name, name, name_len)) {
748 			ubi_close_volume(re->desc);
749 			kfree(re);
750 			continue;
751 		}
752 
753 		re->new_name_len = name_len;
754 		memcpy(re->new_name, name, name_len);
755 		list_add_tail(&re->list, &rename_list);
756 		dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
757 			vol_id, re->desc->vol->name, name);
758 	}
759 
760 	if (list_empty(&rename_list))
761 		return 0;
762 
763 	/* Find out the volumes which have to be removed */
764 	list_for_each_entry(re, &rename_list, list) {
765 		struct ubi_volume_desc *desc;
766 		int no_remove_needed = 0;
767 
768 		/*
769 		 * Volume @re->vol_id is going to be re-named to
770 		 * @re->new_name, while its current name is @name. If a volume
771 		 * with name @re->new_name currently exists, it has to be
772 		 * removed, unless it is also re-named in the request (@req).
773 		 */
774 		list_for_each_entry(re1, &rename_list, list) {
775 			if (re->new_name_len == re1->desc->vol->name_len &&
776 			    !memcmp(re->new_name, re1->desc->vol->name,
777 				    re1->desc->vol->name_len)) {
778 				no_remove_needed = 1;
779 				break;
780 			}
781 		}
782 
783 		if (no_remove_needed)
784 			continue;
785 
786 		/*
787 		 * It seems we need to remove volume with name @re->new_name,
788 		 * if it exists.
789 		 */
790 		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
791 					  UBI_EXCLUSIVE);
792 		if (IS_ERR(desc)) {
793 			err = PTR_ERR(desc);
794 			if (err == -ENODEV)
795 				/* Re-naming into a non-existing volume name */
796 				continue;
797 
798 			/* The volume exists but busy, or an error occurred */
799 			ubi_err("cannot open volume \"%s\", error %d",
800 				re->new_name, err);
801 			goto out_free;
802 		}
803 
804 		re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
805 		if (!re1) {
806 			err = -ENOMEM;
807 			ubi_close_volume(desc);
808 			goto out_free;
809 		}
810 
811 		re1->remove = 1;
812 		re1->desc = desc;
813 		list_add(&re1->list, &rename_list);
814 		dbg_msg("will remove volume %d, name \"%s\"",
815 			re1->desc->vol->vol_id, re1->desc->vol->name);
816 	}
817 
818 	mutex_lock(&ubi->device_mutex);
819 	err = ubi_rename_volumes(ubi, &rename_list);
820 	mutex_unlock(&ubi->device_mutex);
821 
822 out_free:
823 	list_for_each_entry_safe(re, re1, &rename_list, list) {
824 		ubi_close_volume(re->desc);
825 		list_del(&re->list);
826 		kfree(re);
827 	}
828 	return err;
829 }
830 
831 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
832 			   unsigned long arg)
833 {
834 	int err = 0;
835 	struct ubi_device *ubi;
836 	struct ubi_volume_desc *desc;
837 	void __user *argp = (void __user *)arg;
838 
839 	if (!capable(CAP_SYS_RESOURCE))
840 		return -EPERM;
841 
842 	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
843 	if (!ubi)
844 		return -ENODEV;
845 
846 	switch (cmd) {
847 	/* Create volume command */
848 	case UBI_IOCMKVOL:
849 	{
850 		struct ubi_mkvol_req req;
851 
852 		dbg_gen("create volume");
853 		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
854 		if (err) {
855 			err = -EFAULT;
856 			break;
857 		}
858 
859 		err = verify_mkvol_req(ubi, &req);
860 		if (err)
861 			break;
862 
863 		mutex_lock(&ubi->device_mutex);
864 		err = ubi_create_volume(ubi, &req);
865 		mutex_unlock(&ubi->device_mutex);
866 		if (err)
867 			break;
868 
869 		err = put_user(req.vol_id, (__user int32_t *)argp);
870 		if (err)
871 			err = -EFAULT;
872 
873 		break;
874 	}
875 
876 	/* Remove volume command */
877 	case UBI_IOCRMVOL:
878 	{
879 		int vol_id;
880 
881 		dbg_gen("remove volume");
882 		err = get_user(vol_id, (__user int32_t *)argp);
883 		if (err) {
884 			err = -EFAULT;
885 			break;
886 		}
887 
888 		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
889 		if (IS_ERR(desc)) {
890 			err = PTR_ERR(desc);
891 			break;
892 		}
893 
894 		mutex_lock(&ubi->device_mutex);
895 		err = ubi_remove_volume(desc, 0);
896 		mutex_unlock(&ubi->device_mutex);
897 
898 		/*
899 		 * The volume is deleted (unless an error occurred), and the
900 		 * 'struct ubi_volume' object will be freed when
901 		 * 'ubi_close_volume()' will call 'put_device()'.
902 		 */
903 		ubi_close_volume(desc);
904 		break;
905 	}
906 
907 	/* Re-size volume command */
908 	case UBI_IOCRSVOL:
909 	{
910 		int pebs;
911 		struct ubi_rsvol_req req;
912 
913 		dbg_gen("re-size volume");
914 		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
915 		if (err) {
916 			err = -EFAULT;
917 			break;
918 		}
919 
920 		err = verify_rsvol_req(ubi, &req);
921 		if (err)
922 			break;
923 
924 		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
925 		if (IS_ERR(desc)) {
926 			err = PTR_ERR(desc);
927 			break;
928 		}
929 
930 		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
931 			       desc->vol->usable_leb_size);
932 
933 		mutex_lock(&ubi->device_mutex);
934 		err = ubi_resize_volume(desc, pebs);
935 		mutex_unlock(&ubi->device_mutex);
936 		ubi_close_volume(desc);
937 		break;
938 	}
939 
940 	/* Re-name volumes command */
941 	case UBI_IOCRNVOL:
942 	{
943 		struct ubi_rnvol_req *req;
944 
945 		dbg_msg("re-name volumes");
946 		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
947 		if (!req) {
948 			err = -ENOMEM;
949 			break;
950 		};
951 
952 		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
953 		if (err) {
954 			err = -EFAULT;
955 			kfree(req);
956 			break;
957 		}
958 
959 		err = rename_volumes(ubi, req);
960 		kfree(req);
961 		break;
962 	}
963 
964 	default:
965 		err = -ENOTTY;
966 		break;
967 	}
968 
969 	ubi_put_device(ubi);
970 	return err;
971 }
972 
973 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
974 			    unsigned long arg)
975 {
976 	int err = 0;
977 	void __user *argp = (void __user *)arg;
978 
979 	if (!capable(CAP_SYS_RESOURCE))
980 		return -EPERM;
981 
982 	switch (cmd) {
983 	/* Attach an MTD device command */
984 	case UBI_IOCATT:
985 	{
986 		struct ubi_attach_req req;
987 		struct mtd_info *mtd;
988 
989 		dbg_gen("attach MTD device");
990 		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
991 		if (err) {
992 			err = -EFAULT;
993 			break;
994 		}
995 
996 		if (req.mtd_num < 0 ||
997 		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
998 			err = -EINVAL;
999 			break;
1000 		}
1001 
1002 		mtd = get_mtd_device(NULL, req.mtd_num);
1003 		if (IS_ERR(mtd)) {
1004 			err = PTR_ERR(mtd);
1005 			break;
1006 		}
1007 
1008 		/*
1009 		 * Note, further request verification is done by
1010 		 * 'ubi_attach_mtd_dev()'.
1011 		 */
1012 		mutex_lock(&ubi_devices_mutex);
1013 		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
1014 		mutex_unlock(&ubi_devices_mutex);
1015 		if (err < 0)
1016 			put_mtd_device(mtd);
1017 		else
1018 			/* @err contains UBI device number */
1019 			err = put_user(err, (__user int32_t *)argp);
1020 
1021 		break;
1022 	}
1023 
1024 	/* Detach an MTD device command */
1025 	case UBI_IOCDET:
1026 	{
1027 		int ubi_num;
1028 
1029 		dbg_gen("detach MTD device");
1030 		err = get_user(ubi_num, (__user int32_t *)argp);
1031 		if (err) {
1032 			err = -EFAULT;
1033 			break;
1034 		}
1035 
1036 		mutex_lock(&ubi_devices_mutex);
1037 		err = ubi_detach_mtd_dev(ubi_num, 0);
1038 		mutex_unlock(&ubi_devices_mutex);
1039 		break;
1040 	}
1041 
1042 	default:
1043 		err = -ENOTTY;
1044 		break;
1045 	}
1046 
1047 	return err;
1048 }
1049 
1050 #ifdef CONFIG_COMPAT
1051 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1052 				  unsigned long arg)
1053 {
1054 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1055 
1056 	return vol_cdev_ioctl(file, cmd, translated_arg);
1057 }
1058 
1059 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1060 				  unsigned long arg)
1061 {
1062 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1063 
1064 	return ubi_cdev_ioctl(file, cmd, translated_arg);
1065 }
1066 
1067 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1068 				   unsigned long arg)
1069 {
1070 	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1071 
1072 	return ctrl_cdev_ioctl(file, cmd, translated_arg);
1073 }
1074 #else
1075 #define vol_cdev_compat_ioctl  NULL
1076 #define ubi_cdev_compat_ioctl  NULL
1077 #define ctrl_cdev_compat_ioctl NULL
1078 #endif
1079 
1080 /* UBI volume character device operations */
1081 const struct file_operations ubi_vol_cdev_operations = {
1082 	.owner          = THIS_MODULE,
1083 	.open           = vol_cdev_open,
1084 	.release        = vol_cdev_release,
1085 	.llseek         = vol_cdev_llseek,
1086 	.read           = vol_cdev_read,
1087 	.write          = vol_cdev_write,
1088 	.fsync		= vol_cdev_fsync,
1089 	.unlocked_ioctl = vol_cdev_ioctl,
1090 	.compat_ioctl   = vol_cdev_compat_ioctl,
1091 };
1092 
1093 /* UBI character device operations */
1094 const struct file_operations ubi_cdev_operations = {
1095 	.owner          = THIS_MODULE,
1096 	.llseek         = no_llseek,
1097 	.unlocked_ioctl = ubi_cdev_ioctl,
1098 	.compat_ioctl   = ubi_cdev_compat_ioctl,
1099 };
1100 
1101 /* UBI control character device operations */
1102 const struct file_operations ubi_ctrl_cdev_operations = {
1103 	.owner          = THIS_MODULE,
1104 	.unlocked_ioctl = ctrl_cdev_ioctl,
1105 	.compat_ioctl   = ctrl_cdev_compat_ioctl,
1106 	.llseek		= no_llseek,
1107 };
1108