xref: /linux/fs/ext4/ioctl.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * linux/fs/ext4/ioctl.c
3  *
4  * Copyright (C) 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  */
9 
10 #include <linux/fs.h>
11 #include <linux/capability.h>
12 #include <linux/time.h>
13 #include <linux/compat.h>
14 #include <linux/mount.h>
15 #include <linux/file.h>
16 #include <linux/random.h>
17 #include <asm/uaccess.h>
18 #include "ext4_jbd2.h"
19 #include "ext4.h"
20 
21 #define MAX_32_NUM ((((unsigned long long) 1) << 32) - 1)
22 
23 /**
24  * Swap memory between @a and @b for @len bytes.
25  *
26  * @a:          pointer to first memory area
27  * @b:          pointer to second memory area
28  * @len:        number of bytes to swap
29  *
30  */
31 static void memswap(void *a, void *b, size_t len)
32 {
33 	unsigned char *ap, *bp;
34 
35 	ap = (unsigned char *)a;
36 	bp = (unsigned char *)b;
37 	while (len-- > 0) {
38 		swap(*ap, *bp);
39 		ap++;
40 		bp++;
41 	}
42 }
43 
44 /**
45  * Swap i_data and associated attributes between @inode1 and @inode2.
46  * This function is used for the primary swap between inode1 and inode2
47  * and also to revert this primary swap in case of errors.
48  *
49  * Therefore you have to make sure, that calling this method twice
50  * will revert all changes.
51  *
52  * @inode1:     pointer to first inode
53  * @inode2:     pointer to second inode
54  */
55 static void swap_inode_data(struct inode *inode1, struct inode *inode2)
56 {
57 	loff_t isize;
58 	struct ext4_inode_info *ei1;
59 	struct ext4_inode_info *ei2;
60 
61 	ei1 = EXT4_I(inode1);
62 	ei2 = EXT4_I(inode2);
63 
64 	memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags));
65 	memswap(&inode1->i_version, &inode2->i_version,
66 		  sizeof(inode1->i_version));
67 	memswap(&inode1->i_blocks, &inode2->i_blocks,
68 		  sizeof(inode1->i_blocks));
69 	memswap(&inode1->i_bytes, &inode2->i_bytes, sizeof(inode1->i_bytes));
70 	memswap(&inode1->i_atime, &inode2->i_atime, sizeof(inode1->i_atime));
71 	memswap(&inode1->i_mtime, &inode2->i_mtime, sizeof(inode1->i_mtime));
72 
73 	memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
74 	memswap(&ei1->i_flags, &ei2->i_flags, sizeof(ei1->i_flags));
75 	memswap(&ei1->i_disksize, &ei2->i_disksize, sizeof(ei1->i_disksize));
76 	ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
77 	ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
78 
79 	isize = i_size_read(inode1);
80 	i_size_write(inode1, i_size_read(inode2));
81 	i_size_write(inode2, isize);
82 }
83 
84 /**
85  * Swap the information from the given @inode and the inode
86  * EXT4_BOOT_LOADER_INO. It will basically swap i_data and all other
87  * important fields of the inodes.
88  *
89  * @sb:         the super block of the filesystem
90  * @inode:      the inode to swap with EXT4_BOOT_LOADER_INO
91  *
92  */
93 static long swap_inode_boot_loader(struct super_block *sb,
94 				struct inode *inode)
95 {
96 	handle_t *handle;
97 	int err;
98 	struct inode *inode_bl;
99 	struct ext4_inode_info *ei_bl;
100 	struct ext4_sb_info *sbi = EXT4_SB(sb);
101 
102 	if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode))
103 		return -EINVAL;
104 
105 	if (!inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN))
106 		return -EPERM;
107 
108 	inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO);
109 	if (IS_ERR(inode_bl))
110 		return PTR_ERR(inode_bl);
111 	ei_bl = EXT4_I(inode_bl);
112 
113 	filemap_flush(inode->i_mapping);
114 	filemap_flush(inode_bl->i_mapping);
115 
116 	/* Protect orig inodes against a truncate and make sure,
117 	 * that only 1 swap_inode_boot_loader is running. */
118 	lock_two_nondirectories(inode, inode_bl);
119 
120 	truncate_inode_pages(&inode->i_data, 0);
121 	truncate_inode_pages(&inode_bl->i_data, 0);
122 
123 	/* Wait for all existing dio workers */
124 	ext4_inode_block_unlocked_dio(inode);
125 	ext4_inode_block_unlocked_dio(inode_bl);
126 	inode_dio_wait(inode);
127 	inode_dio_wait(inode_bl);
128 
129 	handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
130 	if (IS_ERR(handle)) {
131 		err = -EINVAL;
132 		goto journal_err_out;
133 	}
134 
135 	/* Protect extent tree against block allocations via delalloc */
136 	ext4_double_down_write_data_sem(inode, inode_bl);
137 
138 	if (inode_bl->i_nlink == 0) {
139 		/* this inode has never been used as a BOOT_LOADER */
140 		set_nlink(inode_bl, 1);
141 		i_uid_write(inode_bl, 0);
142 		i_gid_write(inode_bl, 0);
143 		inode_bl->i_flags = 0;
144 		ei_bl->i_flags = 0;
145 		inode_bl->i_version = 1;
146 		i_size_write(inode_bl, 0);
147 		inode_bl->i_mode = S_IFREG;
148 		if (EXT4_HAS_INCOMPAT_FEATURE(sb,
149 					      EXT4_FEATURE_INCOMPAT_EXTENTS)) {
150 			ext4_set_inode_flag(inode_bl, EXT4_INODE_EXTENTS);
151 			ext4_ext_tree_init(handle, inode_bl);
152 		} else
153 			memset(ei_bl->i_data, 0, sizeof(ei_bl->i_data));
154 	}
155 
156 	swap_inode_data(inode, inode_bl);
157 
158 	inode->i_ctime = inode_bl->i_ctime = ext4_current_time(inode);
159 
160 	spin_lock(&sbi->s_next_gen_lock);
161 	inode->i_generation = sbi->s_next_generation++;
162 	inode_bl->i_generation = sbi->s_next_generation++;
163 	spin_unlock(&sbi->s_next_gen_lock);
164 
165 	ext4_discard_preallocations(inode);
166 
167 	err = ext4_mark_inode_dirty(handle, inode);
168 	if (err < 0) {
169 		ext4_warning(inode->i_sb,
170 			"couldn't mark inode #%lu dirty (err %d)",
171 			inode->i_ino, err);
172 		/* Revert all changes: */
173 		swap_inode_data(inode, inode_bl);
174 	} else {
175 		err = ext4_mark_inode_dirty(handle, inode_bl);
176 		if (err < 0) {
177 			ext4_warning(inode_bl->i_sb,
178 				"couldn't mark inode #%lu dirty (err %d)",
179 				inode_bl->i_ino, err);
180 			/* Revert all changes: */
181 			swap_inode_data(inode, inode_bl);
182 			ext4_mark_inode_dirty(handle, inode);
183 		}
184 	}
185 	ext4_journal_stop(handle);
186 	ext4_double_up_write_data_sem(inode, inode_bl);
187 
188 journal_err_out:
189 	ext4_inode_resume_unlocked_dio(inode);
190 	ext4_inode_resume_unlocked_dio(inode_bl);
191 	unlock_two_nondirectories(inode, inode_bl);
192 	iput(inode_bl);
193 	return err;
194 }
195 
196 static int uuid_is_zero(__u8 u[16])
197 {
198 	int	i;
199 
200 	for (i = 0; i < 16; i++)
201 		if (u[i])
202 			return 0;
203 	return 1;
204 }
205 
206 long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
207 {
208 	struct inode *inode = file_inode(filp);
209 	struct super_block *sb = inode->i_sb;
210 	struct ext4_inode_info *ei = EXT4_I(inode);
211 	unsigned int flags;
212 
213 	ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
214 
215 	switch (cmd) {
216 	case EXT4_IOC_GETFLAGS:
217 		ext4_get_inode_flags(ei);
218 		flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
219 		return put_user(flags, (int __user *) arg);
220 	case EXT4_IOC_SETFLAGS: {
221 		handle_t *handle = NULL;
222 		int err, migrate = 0;
223 		struct ext4_iloc iloc;
224 		unsigned int oldflags, mask, i;
225 		unsigned int jflag;
226 
227 		if (!inode_owner_or_capable(inode))
228 			return -EACCES;
229 
230 		if (get_user(flags, (int __user *) arg))
231 			return -EFAULT;
232 
233 		err = mnt_want_write_file(filp);
234 		if (err)
235 			return err;
236 
237 		flags = ext4_mask_flags(inode->i_mode, flags);
238 
239 		err = -EPERM;
240 		mutex_lock(&inode->i_mutex);
241 		/* Is it quota file? Do not allow user to mess with it */
242 		if (IS_NOQUOTA(inode))
243 			goto flags_out;
244 
245 		oldflags = ei->i_flags;
246 
247 		/* The JOURNAL_DATA flag is modifiable only by root */
248 		jflag = flags & EXT4_JOURNAL_DATA_FL;
249 
250 		/*
251 		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
252 		 * the relevant capability.
253 		 *
254 		 * This test looks nicer. Thanks to Pauline Middelink
255 		 */
256 		if ((flags ^ oldflags) & (EXT4_APPEND_FL | EXT4_IMMUTABLE_FL)) {
257 			if (!capable(CAP_LINUX_IMMUTABLE))
258 				goto flags_out;
259 		}
260 
261 		/*
262 		 * The JOURNAL_DATA flag can only be changed by
263 		 * the relevant capability.
264 		 */
265 		if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) {
266 			if (!capable(CAP_SYS_RESOURCE))
267 				goto flags_out;
268 		}
269 		if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
270 			migrate = 1;
271 
272 		if (flags & EXT4_EOFBLOCKS_FL) {
273 			/* we don't support adding EOFBLOCKS flag */
274 			if (!(oldflags & EXT4_EOFBLOCKS_FL)) {
275 				err = -EOPNOTSUPP;
276 				goto flags_out;
277 			}
278 		} else if (oldflags & EXT4_EOFBLOCKS_FL)
279 			ext4_truncate(inode);
280 
281 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
282 		if (IS_ERR(handle)) {
283 			err = PTR_ERR(handle);
284 			goto flags_out;
285 		}
286 		if (IS_SYNC(inode))
287 			ext4_handle_sync(handle);
288 		err = ext4_reserve_inode_write(handle, inode, &iloc);
289 		if (err)
290 			goto flags_err;
291 
292 		for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
293 			if (!(mask & EXT4_FL_USER_MODIFIABLE))
294 				continue;
295 			if (mask & flags)
296 				ext4_set_inode_flag(inode, i);
297 			else
298 				ext4_clear_inode_flag(inode, i);
299 		}
300 
301 		ext4_set_inode_flags(inode);
302 		inode->i_ctime = ext4_current_time(inode);
303 
304 		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
305 flags_err:
306 		ext4_journal_stop(handle);
307 		if (err)
308 			goto flags_out;
309 
310 		if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL))
311 			err = ext4_change_inode_journal_flag(inode, jflag);
312 		if (err)
313 			goto flags_out;
314 		if (migrate) {
315 			if (flags & EXT4_EXTENTS_FL)
316 				err = ext4_ext_migrate(inode);
317 			else
318 				err = ext4_ind_migrate(inode);
319 		}
320 
321 flags_out:
322 		mutex_unlock(&inode->i_mutex);
323 		mnt_drop_write_file(filp);
324 		return err;
325 	}
326 	case EXT4_IOC_GETVERSION:
327 	case EXT4_IOC_GETVERSION_OLD:
328 		return put_user(inode->i_generation, (int __user *) arg);
329 	case EXT4_IOC_SETVERSION:
330 	case EXT4_IOC_SETVERSION_OLD: {
331 		handle_t *handle;
332 		struct ext4_iloc iloc;
333 		__u32 generation;
334 		int err;
335 
336 		if (!inode_owner_or_capable(inode))
337 			return -EPERM;
338 
339 		if (ext4_has_metadata_csum(inode->i_sb)) {
340 			ext4_warning(sb, "Setting inode version is not "
341 				     "supported with metadata_csum enabled.");
342 			return -ENOTTY;
343 		}
344 
345 		err = mnt_want_write_file(filp);
346 		if (err)
347 			return err;
348 		if (get_user(generation, (int __user *) arg)) {
349 			err = -EFAULT;
350 			goto setversion_out;
351 		}
352 
353 		mutex_lock(&inode->i_mutex);
354 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
355 		if (IS_ERR(handle)) {
356 			err = PTR_ERR(handle);
357 			goto unlock_out;
358 		}
359 		err = ext4_reserve_inode_write(handle, inode, &iloc);
360 		if (err == 0) {
361 			inode->i_ctime = ext4_current_time(inode);
362 			inode->i_generation = generation;
363 			err = ext4_mark_iloc_dirty(handle, inode, &iloc);
364 		}
365 		ext4_journal_stop(handle);
366 
367 unlock_out:
368 		mutex_unlock(&inode->i_mutex);
369 setversion_out:
370 		mnt_drop_write_file(filp);
371 		return err;
372 	}
373 	case EXT4_IOC_GROUP_EXTEND: {
374 		ext4_fsblk_t n_blocks_count;
375 		int err, err2=0;
376 
377 		err = ext4_resize_begin(sb);
378 		if (err)
379 			return err;
380 
381 		if (get_user(n_blocks_count, (__u32 __user *)arg)) {
382 			err = -EFAULT;
383 			goto group_extend_out;
384 		}
385 
386 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
387 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
388 			ext4_msg(sb, KERN_ERR,
389 				 "Online resizing not supported with bigalloc");
390 			err = -EOPNOTSUPP;
391 			goto group_extend_out;
392 		}
393 
394 		err = mnt_want_write_file(filp);
395 		if (err)
396 			goto group_extend_out;
397 
398 		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);
399 		if (EXT4_SB(sb)->s_journal) {
400 			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
401 			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
402 			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
403 		}
404 		if (err == 0)
405 			err = err2;
406 		mnt_drop_write_file(filp);
407 group_extend_out:
408 		ext4_resize_end(sb);
409 		return err;
410 	}
411 
412 	case EXT4_IOC_MOVE_EXT: {
413 		struct move_extent me;
414 		struct fd donor;
415 		int err;
416 
417 		if (!(filp->f_mode & FMODE_READ) ||
418 		    !(filp->f_mode & FMODE_WRITE))
419 			return -EBADF;
420 
421 		if (copy_from_user(&me,
422 			(struct move_extent __user *)arg, sizeof(me)))
423 			return -EFAULT;
424 		me.moved_len = 0;
425 
426 		donor = fdget(me.donor_fd);
427 		if (!donor.file)
428 			return -EBADF;
429 
430 		if (!(donor.file->f_mode & FMODE_WRITE)) {
431 			err = -EBADF;
432 			goto mext_out;
433 		}
434 
435 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
436 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
437 			ext4_msg(sb, KERN_ERR,
438 				 "Online defrag not supported with bigalloc");
439 			err = -EOPNOTSUPP;
440 			goto mext_out;
441 		}
442 
443 		err = mnt_want_write_file(filp);
444 		if (err)
445 			goto mext_out;
446 
447 		err = ext4_move_extents(filp, donor.file, me.orig_start,
448 					me.donor_start, me.len, &me.moved_len);
449 		mnt_drop_write_file(filp);
450 
451 		if (copy_to_user((struct move_extent __user *)arg,
452 				 &me, sizeof(me)))
453 			err = -EFAULT;
454 mext_out:
455 		fdput(donor);
456 		return err;
457 	}
458 
459 	case EXT4_IOC_GROUP_ADD: {
460 		struct ext4_new_group_data input;
461 		int err, err2=0;
462 
463 		err = ext4_resize_begin(sb);
464 		if (err)
465 			return err;
466 
467 		if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg,
468 				sizeof(input))) {
469 			err = -EFAULT;
470 			goto group_add_out;
471 		}
472 
473 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
474 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
475 			ext4_msg(sb, KERN_ERR,
476 				 "Online resizing not supported with bigalloc");
477 			err = -EOPNOTSUPP;
478 			goto group_add_out;
479 		}
480 
481 		err = mnt_want_write_file(filp);
482 		if (err)
483 			goto group_add_out;
484 
485 		err = ext4_group_add(sb, &input);
486 		if (EXT4_SB(sb)->s_journal) {
487 			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
488 			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
489 			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
490 		}
491 		if (err == 0)
492 			err = err2;
493 		mnt_drop_write_file(filp);
494 		if (!err && ext4_has_group_desc_csum(sb) &&
495 		    test_opt(sb, INIT_INODE_TABLE))
496 			err = ext4_register_li_request(sb, input.group);
497 group_add_out:
498 		ext4_resize_end(sb);
499 		return err;
500 	}
501 
502 	case EXT4_IOC_MIGRATE:
503 	{
504 		int err;
505 		if (!inode_owner_or_capable(inode))
506 			return -EACCES;
507 
508 		err = mnt_want_write_file(filp);
509 		if (err)
510 			return err;
511 		/*
512 		 * inode_mutex prevent write and truncate on the file.
513 		 * Read still goes through. We take i_data_sem in
514 		 * ext4_ext_swap_inode_data before we switch the
515 		 * inode format to prevent read.
516 		 */
517 		mutex_lock(&(inode->i_mutex));
518 		err = ext4_ext_migrate(inode);
519 		mutex_unlock(&(inode->i_mutex));
520 		mnt_drop_write_file(filp);
521 		return err;
522 	}
523 
524 	case EXT4_IOC_ALLOC_DA_BLKS:
525 	{
526 		int err;
527 		if (!inode_owner_or_capable(inode))
528 			return -EACCES;
529 
530 		err = mnt_want_write_file(filp);
531 		if (err)
532 			return err;
533 		err = ext4_alloc_da_blocks(inode);
534 		mnt_drop_write_file(filp);
535 		return err;
536 	}
537 
538 	case EXT4_IOC_SWAP_BOOT:
539 	{
540 		int err;
541 		if (!(filp->f_mode & FMODE_WRITE))
542 			return -EBADF;
543 		err = mnt_want_write_file(filp);
544 		if (err)
545 			return err;
546 		err = swap_inode_boot_loader(sb, inode);
547 		mnt_drop_write_file(filp);
548 		return err;
549 	}
550 
551 	case EXT4_IOC_RESIZE_FS: {
552 		ext4_fsblk_t n_blocks_count;
553 		int err = 0, err2 = 0;
554 		ext4_group_t o_group = EXT4_SB(sb)->s_groups_count;
555 
556 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
557 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
558 			ext4_msg(sb, KERN_ERR,
559 				 "Online resizing not (yet) supported with bigalloc");
560 			return -EOPNOTSUPP;
561 		}
562 
563 		if (copy_from_user(&n_blocks_count, (__u64 __user *)arg,
564 				   sizeof(__u64))) {
565 			return -EFAULT;
566 		}
567 
568 		err = ext4_resize_begin(sb);
569 		if (err)
570 			return err;
571 
572 		err = mnt_want_write_file(filp);
573 		if (err)
574 			goto resizefs_out;
575 
576 		err = ext4_resize_fs(sb, n_blocks_count);
577 		if (EXT4_SB(sb)->s_journal) {
578 			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
579 			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
580 			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
581 		}
582 		if (err == 0)
583 			err = err2;
584 		mnt_drop_write_file(filp);
585 		if (!err && (o_group > EXT4_SB(sb)->s_groups_count) &&
586 		    ext4_has_group_desc_csum(sb) &&
587 		    test_opt(sb, INIT_INODE_TABLE))
588 			err = ext4_register_li_request(sb, o_group);
589 
590 resizefs_out:
591 		ext4_resize_end(sb);
592 		return err;
593 	}
594 
595 	case FITRIM:
596 	{
597 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
598 		struct fstrim_range range;
599 		int ret = 0;
600 
601 		if (!capable(CAP_SYS_ADMIN))
602 			return -EPERM;
603 
604 		if (!blk_queue_discard(q))
605 			return -EOPNOTSUPP;
606 
607 		if (copy_from_user(&range, (struct fstrim_range __user *)arg,
608 		    sizeof(range)))
609 			return -EFAULT;
610 
611 		range.minlen = max((unsigned int)range.minlen,
612 				   q->limits.discard_granularity);
613 		ret = ext4_trim_fs(sb, &range);
614 		if (ret < 0)
615 			return ret;
616 
617 		if (copy_to_user((struct fstrim_range __user *)arg, &range,
618 		    sizeof(range)))
619 			return -EFAULT;
620 
621 		return 0;
622 	}
623 	case EXT4_IOC_PRECACHE_EXTENTS:
624 		return ext4_ext_precache(inode);
625 	case EXT4_IOC_SET_ENCRYPTION_POLICY: {
626 #ifdef CONFIG_EXT4_FS_ENCRYPTION
627 		struct ext4_encryption_policy policy;
628 		int err = 0;
629 
630 		if (copy_from_user(&policy,
631 				   (struct ext4_encryption_policy __user *)arg,
632 				   sizeof(policy))) {
633 			err = -EFAULT;
634 			goto encryption_policy_out;
635 		}
636 
637 		err = ext4_process_policy(&policy, inode);
638 encryption_policy_out:
639 		return err;
640 #else
641 		return -EOPNOTSUPP;
642 #endif
643 	}
644 	case EXT4_IOC_GET_ENCRYPTION_PWSALT: {
645 		int err, err2;
646 		struct ext4_sb_info *sbi = EXT4_SB(sb);
647 		handle_t *handle;
648 
649 		if (!ext4_sb_has_crypto(sb))
650 			return -EOPNOTSUPP;
651 		if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
652 			err = mnt_want_write_file(filp);
653 			if (err)
654 				return err;
655 			handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
656 			if (IS_ERR(handle)) {
657 				err = PTR_ERR(handle);
658 				goto pwsalt_err_exit;
659 			}
660 			err = ext4_journal_get_write_access(handle, sbi->s_sbh);
661 			if (err)
662 				goto pwsalt_err_journal;
663 			generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
664 			err = ext4_handle_dirty_metadata(handle, NULL,
665 							 sbi->s_sbh);
666 		pwsalt_err_journal:
667 			err2 = ext4_journal_stop(handle);
668 			if (err2 && !err)
669 				err = err2;
670 		pwsalt_err_exit:
671 			mnt_drop_write_file(filp);
672 			if (err)
673 				return err;
674 		}
675 		if (copy_to_user((void __user *) arg,
676 				 sbi->s_es->s_encrypt_pw_salt, 16))
677 			return -EFAULT;
678 		return 0;
679 	}
680 	case EXT4_IOC_GET_ENCRYPTION_POLICY: {
681 #ifdef CONFIG_EXT4_FS_ENCRYPTION
682 		struct ext4_encryption_policy policy;
683 		int err = 0;
684 
685 		if (!ext4_encrypted_inode(inode))
686 			return -ENOENT;
687 		err = ext4_get_policy(inode, &policy);
688 		if (err)
689 			return err;
690 		if (copy_to_user((void __user *)arg, &policy, sizeof(policy)))
691 			return -EFAULT;
692 		return 0;
693 #else
694 		return -EOPNOTSUPP;
695 #endif
696 	}
697 	default:
698 		return -ENOTTY;
699 	}
700 }
701 
702 #ifdef CONFIG_COMPAT
703 long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
704 {
705 	/* These are just misnamed, they actually get/put from/to user an int */
706 	switch (cmd) {
707 	case EXT4_IOC32_GETFLAGS:
708 		cmd = EXT4_IOC_GETFLAGS;
709 		break;
710 	case EXT4_IOC32_SETFLAGS:
711 		cmd = EXT4_IOC_SETFLAGS;
712 		break;
713 	case EXT4_IOC32_GETVERSION:
714 		cmd = EXT4_IOC_GETVERSION;
715 		break;
716 	case EXT4_IOC32_SETVERSION:
717 		cmd = EXT4_IOC_SETVERSION;
718 		break;
719 	case EXT4_IOC32_GROUP_EXTEND:
720 		cmd = EXT4_IOC_GROUP_EXTEND;
721 		break;
722 	case EXT4_IOC32_GETVERSION_OLD:
723 		cmd = EXT4_IOC_GETVERSION_OLD;
724 		break;
725 	case EXT4_IOC32_SETVERSION_OLD:
726 		cmd = EXT4_IOC_SETVERSION_OLD;
727 		break;
728 	case EXT4_IOC32_GETRSVSZ:
729 		cmd = EXT4_IOC_GETRSVSZ;
730 		break;
731 	case EXT4_IOC32_SETRSVSZ:
732 		cmd = EXT4_IOC_SETRSVSZ;
733 		break;
734 	case EXT4_IOC32_GROUP_ADD: {
735 		struct compat_ext4_new_group_input __user *uinput;
736 		struct ext4_new_group_input input;
737 		mm_segment_t old_fs;
738 		int err;
739 
740 		uinput = compat_ptr(arg);
741 		err = get_user(input.group, &uinput->group);
742 		err |= get_user(input.block_bitmap, &uinput->block_bitmap);
743 		err |= get_user(input.inode_bitmap, &uinput->inode_bitmap);
744 		err |= get_user(input.inode_table, &uinput->inode_table);
745 		err |= get_user(input.blocks_count, &uinput->blocks_count);
746 		err |= get_user(input.reserved_blocks,
747 				&uinput->reserved_blocks);
748 		if (err)
749 			return -EFAULT;
750 		old_fs = get_fs();
751 		set_fs(KERNEL_DS);
752 		err = ext4_ioctl(file, EXT4_IOC_GROUP_ADD,
753 				 (unsigned long) &input);
754 		set_fs(old_fs);
755 		return err;
756 	}
757 	case EXT4_IOC_MOVE_EXT:
758 	case EXT4_IOC_RESIZE_FS:
759 	case EXT4_IOC_PRECACHE_EXTENTS:
760 	case EXT4_IOC_SET_ENCRYPTION_POLICY:
761 	case EXT4_IOC_GET_ENCRYPTION_PWSALT:
762 	case EXT4_IOC_GET_ENCRYPTION_POLICY:
763 		break;
764 	default:
765 		return -ENOIOCTLCMD;
766 	}
767 	return ext4_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
768 }
769 #endif
770