xref: /linux/fs/btrfs/ioctl.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #include <linux/kernel.h>
7 #include <linux/bio.h>
8 #include <linux/file.h>
9 #include <linux/fs.h>
10 #include <linux/fsnotify.h>
11 #include <linux/pagemap.h>
12 #include <linux/highmem.h>
13 #include <linux/time.h>
14 #include <linux/string.h>
15 #include <linux/backing-dev.h>
16 #include <linux/mount.h>
17 #include <linux/namei.h>
18 #include <linux/writeback.h>
19 #include <linux/compat.h>
20 #include <linux/security.h>
21 #include <linux/xattr.h>
22 #include <linux/mm.h>
23 #include <linux/slab.h>
24 #include <linux/blkdev.h>
25 #include <linux/uuid.h>
26 #include <linux/btrfs.h>
27 #include <linux/uaccess.h>
28 #include <linux/iversion.h>
29 #include <linux/fileattr.h>
30 #include <linux/fsverity.h>
31 #include <linux/sched/xacct.h>
32 #include "ctree.h"
33 #include "disk-io.h"
34 #include "export.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "volumes.h"
38 #include "locking.h"
39 #include "backref.h"
40 #include "send.h"
41 #include "dev-replace.h"
42 #include "props.h"
43 #include "sysfs.h"
44 #include "qgroup.h"
45 #include "tree-log.h"
46 #include "compression.h"
47 #include "space-info.h"
48 #include "block-group.h"
49 #include "fs.h"
50 #include "accessors.h"
51 #include "extent-tree.h"
52 #include "root-tree.h"
53 #include "defrag.h"
54 #include "dir-item.h"
55 #include "uuid-tree.h"
56 #include "ioctl.h"
57 #include "file.h"
58 #include "scrub.h"
59 #include "super.h"
60 
61 #ifdef CONFIG_64BIT
62 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
63  * structures are incorrect, as the timespec structure from userspace
64  * is 4 bytes too small. We define these alternatives here to teach
65  * the kernel about the 32-bit struct packing.
66  */
67 struct btrfs_ioctl_timespec_32 {
68 	__u64 sec;
69 	__u32 nsec;
70 } __attribute__ ((__packed__));
71 
72 struct btrfs_ioctl_received_subvol_args_32 {
73 	char	uuid[BTRFS_UUID_SIZE];	/* in */
74 	__u64	stransid;		/* in */
75 	__u64	rtransid;		/* out */
76 	struct btrfs_ioctl_timespec_32 stime; /* in */
77 	struct btrfs_ioctl_timespec_32 rtime; /* out */
78 	__u64	flags;			/* in */
79 	__u64	reserved[16];		/* in */
80 } __attribute__ ((__packed__));
81 
82 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
83 				struct btrfs_ioctl_received_subvol_args_32)
84 #endif
85 
86 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
87 struct btrfs_ioctl_send_args_32 {
88 	__s64 send_fd;			/* in */
89 	__u64 clone_sources_count;	/* in */
90 	compat_uptr_t clone_sources;	/* in */
91 	__u64 parent_root;		/* in */
92 	__u64 flags;			/* in */
93 	__u32 version;			/* in */
94 	__u8  reserved[28];		/* in */
95 } __attribute__ ((__packed__));
96 
97 #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \
98 			       struct btrfs_ioctl_send_args_32)
99 
100 struct btrfs_ioctl_encoded_io_args_32 {
101 	compat_uptr_t iov;
102 	compat_ulong_t iovcnt;
103 	__s64 offset;
104 	__u64 flags;
105 	__u64 len;
106 	__u64 unencoded_len;
107 	__u64 unencoded_offset;
108 	__u32 compression;
109 	__u32 encryption;
110 	__u8 reserved[64];
111 };
112 
113 #define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \
114 				       struct btrfs_ioctl_encoded_io_args_32)
115 #define BTRFS_IOC_ENCODED_WRITE_32 _IOW(BTRFS_IOCTL_MAGIC, 64, \
116 					struct btrfs_ioctl_encoded_io_args_32)
117 #endif
118 
119 /* Mask out flags that are inappropriate for the given type of inode. */
120 static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
121 		unsigned int flags)
122 {
123 	if (S_ISDIR(inode->i_mode))
124 		return flags;
125 	else if (S_ISREG(inode->i_mode))
126 		return flags & ~FS_DIRSYNC_FL;
127 	else
128 		return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
129 }
130 
131 /*
132  * Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
133  * ioctl.
134  */
135 static unsigned int btrfs_inode_flags_to_fsflags(struct btrfs_inode *binode)
136 {
137 	unsigned int iflags = 0;
138 	u32 flags = binode->flags;
139 	u32 ro_flags = binode->ro_flags;
140 
141 	if (flags & BTRFS_INODE_SYNC)
142 		iflags |= FS_SYNC_FL;
143 	if (flags & BTRFS_INODE_IMMUTABLE)
144 		iflags |= FS_IMMUTABLE_FL;
145 	if (flags & BTRFS_INODE_APPEND)
146 		iflags |= FS_APPEND_FL;
147 	if (flags & BTRFS_INODE_NODUMP)
148 		iflags |= FS_NODUMP_FL;
149 	if (flags & BTRFS_INODE_NOATIME)
150 		iflags |= FS_NOATIME_FL;
151 	if (flags & BTRFS_INODE_DIRSYNC)
152 		iflags |= FS_DIRSYNC_FL;
153 	if (flags & BTRFS_INODE_NODATACOW)
154 		iflags |= FS_NOCOW_FL;
155 	if (ro_flags & BTRFS_INODE_RO_VERITY)
156 		iflags |= FS_VERITY_FL;
157 
158 	if (flags & BTRFS_INODE_NOCOMPRESS)
159 		iflags |= FS_NOCOMP_FL;
160 	else if (flags & BTRFS_INODE_COMPRESS)
161 		iflags |= FS_COMPR_FL;
162 
163 	return iflags;
164 }
165 
166 /*
167  * Update inode->i_flags based on the btrfs internal flags.
168  */
169 void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
170 {
171 	struct btrfs_inode *binode = BTRFS_I(inode);
172 	unsigned int new_fl = 0;
173 
174 	if (binode->flags & BTRFS_INODE_SYNC)
175 		new_fl |= S_SYNC;
176 	if (binode->flags & BTRFS_INODE_IMMUTABLE)
177 		new_fl |= S_IMMUTABLE;
178 	if (binode->flags & BTRFS_INODE_APPEND)
179 		new_fl |= S_APPEND;
180 	if (binode->flags & BTRFS_INODE_NOATIME)
181 		new_fl |= S_NOATIME;
182 	if (binode->flags & BTRFS_INODE_DIRSYNC)
183 		new_fl |= S_DIRSYNC;
184 	if (binode->ro_flags & BTRFS_INODE_RO_VERITY)
185 		new_fl |= S_VERITY;
186 
187 	set_mask_bits(&inode->i_flags,
188 		      S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC |
189 		      S_VERITY, new_fl);
190 }
191 
192 /*
193  * Check if @flags are a supported and valid set of FS_*_FL flags and that
194  * the old and new flags are not conflicting
195  */
196 static int check_fsflags(unsigned int old_flags, unsigned int flags)
197 {
198 	if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
199 		      FS_NOATIME_FL | FS_NODUMP_FL | \
200 		      FS_SYNC_FL | FS_DIRSYNC_FL | \
201 		      FS_NOCOMP_FL | FS_COMPR_FL |
202 		      FS_NOCOW_FL))
203 		return -EOPNOTSUPP;
204 
205 	/* COMPR and NOCOMP on new/old are valid */
206 	if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
207 		return -EINVAL;
208 
209 	if ((flags & FS_COMPR_FL) && (flags & FS_NOCOW_FL))
210 		return -EINVAL;
211 
212 	/* NOCOW and compression options are mutually exclusive */
213 	if ((old_flags & FS_NOCOW_FL) && (flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
214 		return -EINVAL;
215 	if ((flags & FS_NOCOW_FL) && (old_flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
216 		return -EINVAL;
217 
218 	return 0;
219 }
220 
221 static int check_fsflags_compatible(struct btrfs_fs_info *fs_info,
222 				    unsigned int flags)
223 {
224 	if (btrfs_is_zoned(fs_info) && (flags & FS_NOCOW_FL))
225 		return -EPERM;
226 
227 	return 0;
228 }
229 
230 int btrfs_check_ioctl_vol_args_path(const struct btrfs_ioctl_vol_args *vol_args)
231 {
232 	if (memchr(vol_args->name, 0, sizeof(vol_args->name)) == NULL)
233 		return -ENAMETOOLONG;
234 	return 0;
235 }
236 
237 static int btrfs_check_ioctl_vol_args2_subvol_name(const struct btrfs_ioctl_vol_args_v2 *vol_args2)
238 {
239 	if (memchr(vol_args2->name, 0, sizeof(vol_args2->name)) == NULL)
240 		return -ENAMETOOLONG;
241 	return 0;
242 }
243 
244 /*
245  * Set flags/xflags from the internal inode flags. The remaining items of
246  * fsxattr are zeroed.
247  */
248 int btrfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
249 {
250 	struct btrfs_inode *binode = BTRFS_I(d_inode(dentry));
251 
252 	fileattr_fill_flags(fa, btrfs_inode_flags_to_fsflags(binode));
253 	return 0;
254 }
255 
256 int btrfs_fileattr_set(struct mnt_idmap *idmap,
257 		       struct dentry *dentry, struct fileattr *fa)
258 {
259 	struct inode *inode = d_inode(dentry);
260 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
261 	struct btrfs_inode *binode = BTRFS_I(inode);
262 	struct btrfs_root *root = binode->root;
263 	struct btrfs_trans_handle *trans;
264 	unsigned int fsflags, old_fsflags;
265 	int ret;
266 	const char *comp = NULL;
267 	u32 binode_flags;
268 
269 	if (btrfs_root_readonly(root))
270 		return -EROFS;
271 
272 	if (fileattr_has_fsx(fa))
273 		return -EOPNOTSUPP;
274 
275 	fsflags = btrfs_mask_fsflags_for_type(inode, fa->flags);
276 	old_fsflags = btrfs_inode_flags_to_fsflags(binode);
277 	ret = check_fsflags(old_fsflags, fsflags);
278 	if (ret)
279 		return ret;
280 
281 	ret = check_fsflags_compatible(fs_info, fsflags);
282 	if (ret)
283 		return ret;
284 
285 	binode_flags = binode->flags;
286 	if (fsflags & FS_SYNC_FL)
287 		binode_flags |= BTRFS_INODE_SYNC;
288 	else
289 		binode_flags &= ~BTRFS_INODE_SYNC;
290 	if (fsflags & FS_IMMUTABLE_FL)
291 		binode_flags |= BTRFS_INODE_IMMUTABLE;
292 	else
293 		binode_flags &= ~BTRFS_INODE_IMMUTABLE;
294 	if (fsflags & FS_APPEND_FL)
295 		binode_flags |= BTRFS_INODE_APPEND;
296 	else
297 		binode_flags &= ~BTRFS_INODE_APPEND;
298 	if (fsflags & FS_NODUMP_FL)
299 		binode_flags |= BTRFS_INODE_NODUMP;
300 	else
301 		binode_flags &= ~BTRFS_INODE_NODUMP;
302 	if (fsflags & FS_NOATIME_FL)
303 		binode_flags |= BTRFS_INODE_NOATIME;
304 	else
305 		binode_flags &= ~BTRFS_INODE_NOATIME;
306 
307 	/* If coming from FS_IOC_FSSETXATTR then skip unconverted flags */
308 	if (!fa->flags_valid) {
309 		/* 1 item for the inode */
310 		trans = btrfs_start_transaction(root, 1);
311 		if (IS_ERR(trans))
312 			return PTR_ERR(trans);
313 		goto update_flags;
314 	}
315 
316 	if (fsflags & FS_DIRSYNC_FL)
317 		binode_flags |= BTRFS_INODE_DIRSYNC;
318 	else
319 		binode_flags &= ~BTRFS_INODE_DIRSYNC;
320 	if (fsflags & FS_NOCOW_FL) {
321 		if (S_ISREG(inode->i_mode)) {
322 			/*
323 			 * It's safe to turn csums off here, no extents exist.
324 			 * Otherwise we want the flag to reflect the real COW
325 			 * status of the file and will not set it.
326 			 */
327 			if (inode->i_size == 0)
328 				binode_flags |= BTRFS_INODE_NODATACOW |
329 						BTRFS_INODE_NODATASUM;
330 		} else {
331 			binode_flags |= BTRFS_INODE_NODATACOW;
332 		}
333 	} else {
334 		/*
335 		 * Revert back under same assumptions as above
336 		 */
337 		if (S_ISREG(inode->i_mode)) {
338 			if (inode->i_size == 0)
339 				binode_flags &= ~(BTRFS_INODE_NODATACOW |
340 						  BTRFS_INODE_NODATASUM);
341 		} else {
342 			binode_flags &= ~BTRFS_INODE_NODATACOW;
343 		}
344 	}
345 
346 	/*
347 	 * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
348 	 * flag may be changed automatically if compression code won't make
349 	 * things smaller.
350 	 */
351 	if (fsflags & FS_NOCOMP_FL) {
352 		binode_flags &= ~BTRFS_INODE_COMPRESS;
353 		binode_flags |= BTRFS_INODE_NOCOMPRESS;
354 	} else if (fsflags & FS_COMPR_FL) {
355 
356 		if (IS_SWAPFILE(inode))
357 			return -ETXTBSY;
358 
359 		binode_flags |= BTRFS_INODE_COMPRESS;
360 		binode_flags &= ~BTRFS_INODE_NOCOMPRESS;
361 
362 		comp = btrfs_compress_type2str(fs_info->compress_type);
363 		if (!comp || comp[0] == 0)
364 			comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
365 	} else {
366 		binode_flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
367 	}
368 
369 	/*
370 	 * 1 for inode item
371 	 * 2 for properties
372 	 */
373 	trans = btrfs_start_transaction(root, 3);
374 	if (IS_ERR(trans))
375 		return PTR_ERR(trans);
376 
377 	if (comp) {
378 		ret = btrfs_set_prop(trans, inode, "btrfs.compression", comp,
379 				     strlen(comp), 0);
380 		if (ret) {
381 			btrfs_abort_transaction(trans, ret);
382 			goto out_end_trans;
383 		}
384 	} else {
385 		ret = btrfs_set_prop(trans, inode, "btrfs.compression", NULL,
386 				     0, 0);
387 		if (ret && ret != -ENODATA) {
388 			btrfs_abort_transaction(trans, ret);
389 			goto out_end_trans;
390 		}
391 	}
392 
393 update_flags:
394 	binode->flags = binode_flags;
395 	btrfs_sync_inode_flags_to_i_flags(inode);
396 	inode_inc_iversion(inode);
397 	inode_set_ctime_current(inode);
398 	ret = btrfs_update_inode(trans, BTRFS_I(inode));
399 
400  out_end_trans:
401 	btrfs_end_transaction(trans);
402 	return ret;
403 }
404 
405 /*
406  * Start exclusive operation @type, return true on success
407  */
408 bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
409 			enum btrfs_exclusive_operation type)
410 {
411 	bool ret = false;
412 
413 	spin_lock(&fs_info->super_lock);
414 	if (fs_info->exclusive_operation == BTRFS_EXCLOP_NONE) {
415 		fs_info->exclusive_operation = type;
416 		ret = true;
417 	}
418 	spin_unlock(&fs_info->super_lock);
419 
420 	return ret;
421 }
422 
423 /*
424  * Conditionally allow to enter the exclusive operation in case it's compatible
425  * with the running one.  This must be paired with btrfs_exclop_start_unlock and
426  * btrfs_exclop_finish.
427  *
428  * Compatibility:
429  * - the same type is already running
430  * - when trying to add a device and balance has been paused
431  * - not BTRFS_EXCLOP_NONE - this is intentionally incompatible and the caller
432  *   must check the condition first that would allow none -> @type
433  */
434 bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
435 				 enum btrfs_exclusive_operation type)
436 {
437 	spin_lock(&fs_info->super_lock);
438 	if (fs_info->exclusive_operation == type ||
439 	    (fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED &&
440 	     type == BTRFS_EXCLOP_DEV_ADD))
441 		return true;
442 
443 	spin_unlock(&fs_info->super_lock);
444 	return false;
445 }
446 
447 void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info)
448 {
449 	spin_unlock(&fs_info->super_lock);
450 }
451 
452 void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
453 {
454 	spin_lock(&fs_info->super_lock);
455 	WRITE_ONCE(fs_info->exclusive_operation, BTRFS_EXCLOP_NONE);
456 	spin_unlock(&fs_info->super_lock);
457 	sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");
458 }
459 
460 void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
461 			  enum btrfs_exclusive_operation op)
462 {
463 	switch (op) {
464 	case BTRFS_EXCLOP_BALANCE_PAUSED:
465 		spin_lock(&fs_info->super_lock);
466 		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
467 		       fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD ||
468 		       fs_info->exclusive_operation == BTRFS_EXCLOP_NONE ||
469 		       fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
470 		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;
471 		spin_unlock(&fs_info->super_lock);
472 		break;
473 	case BTRFS_EXCLOP_BALANCE:
474 		spin_lock(&fs_info->super_lock);
475 		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
476 		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
477 		spin_unlock(&fs_info->super_lock);
478 		break;
479 	default:
480 		btrfs_warn(fs_info,
481 			"invalid exclop balance operation %d requested", op);
482 	}
483 }
484 
485 static int btrfs_ioctl_getversion(struct inode *inode, int __user *arg)
486 {
487 	return put_user(inode->i_generation, arg);
488 }
489 
490 static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,
491 					void __user *arg)
492 {
493 	struct btrfs_device *device;
494 	struct fstrim_range range;
495 	u64 minlen = ULLONG_MAX;
496 	u64 num_devices = 0;
497 	int ret;
498 
499 	if (!capable(CAP_SYS_ADMIN))
500 		return -EPERM;
501 
502 	/*
503 	 * btrfs_trim_block_group() depends on space cache, which is not
504 	 * available in zoned filesystem. So, disallow fitrim on a zoned
505 	 * filesystem for now.
506 	 */
507 	if (btrfs_is_zoned(fs_info))
508 		return -EOPNOTSUPP;
509 
510 	/*
511 	 * If the fs is mounted with nologreplay, which requires it to be
512 	 * mounted in RO mode as well, we can not allow discard on free space
513 	 * inside block groups, because log trees refer to extents that are not
514 	 * pinned in a block group's free space cache (pinning the extents is
515 	 * precisely the first phase of replaying a log tree).
516 	 */
517 	if (btrfs_test_opt(fs_info, NOLOGREPLAY))
518 		return -EROFS;
519 
520 	rcu_read_lock();
521 	list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
522 				dev_list) {
523 		if (!device->bdev || !bdev_max_discard_sectors(device->bdev))
524 			continue;
525 		num_devices++;
526 		minlen = min_t(u64, bdev_discard_granularity(device->bdev),
527 				    minlen);
528 	}
529 	rcu_read_unlock();
530 
531 	if (!num_devices)
532 		return -EOPNOTSUPP;
533 	if (copy_from_user(&range, arg, sizeof(range)))
534 		return -EFAULT;
535 
536 	/*
537 	 * NOTE: Don't truncate the range using super->total_bytes.  Bytenr of
538 	 * block group is in the logical address space, which can be any
539 	 * sectorsize aligned bytenr in  the range [0, U64_MAX].
540 	 */
541 	if (range.len < fs_info->sectorsize)
542 		return -EINVAL;
543 
544 	range.minlen = max(range.minlen, minlen);
545 	ret = btrfs_trim_fs(fs_info, &range);
546 	if (ret < 0)
547 		return ret;
548 
549 	if (copy_to_user(arg, &range, sizeof(range)))
550 		return -EFAULT;
551 
552 	return 0;
553 }
554 
555 int __pure btrfs_is_empty_uuid(u8 *uuid)
556 {
557 	int i;
558 
559 	for (i = 0; i < BTRFS_UUID_SIZE; i++) {
560 		if (uuid[i])
561 			return 0;
562 	}
563 	return 1;
564 }
565 
566 /*
567  * Calculate the number of transaction items to reserve for creating a subvolume
568  * or snapshot, not including the inode, directory entries, or parent directory.
569  */
570 static unsigned int create_subvol_num_items(struct btrfs_qgroup_inherit *inherit)
571 {
572 	/*
573 	 * 1 to add root block
574 	 * 1 to add root item
575 	 * 1 to add root ref
576 	 * 1 to add root backref
577 	 * 1 to add UUID item
578 	 * 1 to add qgroup info
579 	 * 1 to add qgroup limit
580 	 *
581 	 * Ideally the last two would only be accounted if qgroups are enabled,
582 	 * but that can change between now and the time we would insert them.
583 	 */
584 	unsigned int num_items = 7;
585 
586 	if (inherit) {
587 		/* 2 to add qgroup relations for each inherited qgroup */
588 		num_items += 2 * inherit->num_qgroups;
589 	}
590 	return num_items;
591 }
592 
593 static noinline int create_subvol(struct mnt_idmap *idmap,
594 				  struct inode *dir, struct dentry *dentry,
595 				  struct btrfs_qgroup_inherit *inherit)
596 {
597 	struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
598 	struct btrfs_trans_handle *trans;
599 	struct btrfs_key key;
600 	struct btrfs_root_item *root_item;
601 	struct btrfs_inode_item *inode_item;
602 	struct extent_buffer *leaf;
603 	struct btrfs_root *root = BTRFS_I(dir)->root;
604 	struct btrfs_root *new_root;
605 	struct btrfs_block_rsv block_rsv;
606 	struct timespec64 cur_time = current_time(dir);
607 	struct btrfs_new_inode_args new_inode_args = {
608 		.dir = dir,
609 		.dentry = dentry,
610 		.subvol = true,
611 	};
612 	unsigned int trans_num_items;
613 	int ret;
614 	dev_t anon_dev;
615 	u64 objectid;
616 	u64 qgroup_reserved = 0;
617 
618 	root_item = kzalloc(sizeof(*root_item), GFP_KERNEL);
619 	if (!root_item)
620 		return -ENOMEM;
621 
622 	ret = btrfs_get_free_objectid(fs_info->tree_root, &objectid);
623 	if (ret)
624 		goto out_root_item;
625 
626 	/*
627 	 * Don't create subvolume whose level is not zero. Or qgroup will be
628 	 * screwed up since it assumes subvolume qgroup's level to be 0.
629 	 */
630 	if (btrfs_qgroup_level(objectid)) {
631 		ret = -ENOSPC;
632 		goto out_root_item;
633 	}
634 
635 	ret = get_anon_bdev(&anon_dev);
636 	if (ret < 0)
637 		goto out_root_item;
638 
639 	new_inode_args.inode = btrfs_new_subvol_inode(idmap, dir);
640 	if (!new_inode_args.inode) {
641 		ret = -ENOMEM;
642 		goto out_anon_dev;
643 	}
644 	ret = btrfs_new_inode_prepare(&new_inode_args, &trans_num_items);
645 	if (ret)
646 		goto out_inode;
647 	trans_num_items += create_subvol_num_items(inherit);
648 
649 	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
650 	ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
651 					       trans_num_items, false);
652 	if (ret)
653 		goto out_new_inode_args;
654 	qgroup_reserved = block_rsv.qgroup_rsv_reserved;
655 
656 	trans = btrfs_start_transaction(root, 0);
657 	if (IS_ERR(trans)) {
658 		ret = PTR_ERR(trans);
659 		goto out_release_rsv;
660 	}
661 	ret = btrfs_record_root_in_trans(trans, BTRFS_I(dir)->root);
662 	if (ret)
663 		goto out;
664 	btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
665 	qgroup_reserved = 0;
666 	trans->block_rsv = &block_rsv;
667 	trans->bytes_reserved = block_rsv.size;
668 	/* Tree log can't currently deal with an inode which is a new root. */
669 	btrfs_set_log_full_commit(trans);
670 
671 	ret = btrfs_qgroup_inherit(trans, 0, objectid, btrfs_root_id(root), inherit);
672 	if (ret)
673 		goto out;
674 
675 	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,
676 				      0, BTRFS_NESTING_NORMAL);
677 	if (IS_ERR(leaf)) {
678 		ret = PTR_ERR(leaf);
679 		goto out;
680 	}
681 
682 	btrfs_mark_buffer_dirty(trans, leaf);
683 
684 	inode_item = &root_item->inode;
685 	btrfs_set_stack_inode_generation(inode_item, 1);
686 	btrfs_set_stack_inode_size(inode_item, 3);
687 	btrfs_set_stack_inode_nlink(inode_item, 1);
688 	btrfs_set_stack_inode_nbytes(inode_item,
689 				     fs_info->nodesize);
690 	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
691 
692 	btrfs_set_root_flags(root_item, 0);
693 	btrfs_set_root_limit(root_item, 0);
694 	btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
695 
696 	btrfs_set_root_bytenr(root_item, leaf->start);
697 	btrfs_set_root_generation(root_item, trans->transid);
698 	btrfs_set_root_level(root_item, 0);
699 	btrfs_set_root_refs(root_item, 1);
700 	btrfs_set_root_used(root_item, leaf->len);
701 	btrfs_set_root_last_snapshot(root_item, 0);
702 
703 	btrfs_set_root_generation_v2(root_item,
704 			btrfs_root_generation(root_item));
705 	generate_random_guid(root_item->uuid);
706 	btrfs_set_stack_timespec_sec(&root_item->otime, cur_time.tv_sec);
707 	btrfs_set_stack_timespec_nsec(&root_item->otime, cur_time.tv_nsec);
708 	root_item->ctime = root_item->otime;
709 	btrfs_set_root_ctransid(root_item, trans->transid);
710 	btrfs_set_root_otransid(root_item, trans->transid);
711 
712 	btrfs_tree_unlock(leaf);
713 
714 	btrfs_set_root_dirid(root_item, BTRFS_FIRST_FREE_OBJECTID);
715 
716 	key.objectid = objectid;
717 	key.offset = 0;
718 	key.type = BTRFS_ROOT_ITEM_KEY;
719 	ret = btrfs_insert_root(trans, fs_info->tree_root, &key,
720 				root_item);
721 	if (ret) {
722 		/*
723 		 * Since we don't abort the transaction in this case, free the
724 		 * tree block so that we don't leak space and leave the
725 		 * filesystem in an inconsistent state (an extent item in the
726 		 * extent tree with a backreference for a root that does not
727 		 * exists).
728 		 */
729 		btrfs_tree_lock(leaf);
730 		btrfs_clear_buffer_dirty(trans, leaf);
731 		btrfs_tree_unlock(leaf);
732 		btrfs_free_tree_block(trans, objectid, leaf, 0, 1);
733 		free_extent_buffer(leaf);
734 		goto out;
735 	}
736 
737 	free_extent_buffer(leaf);
738 	leaf = NULL;
739 
740 	new_root = btrfs_get_new_fs_root(fs_info, objectid, &anon_dev);
741 	if (IS_ERR(new_root)) {
742 		ret = PTR_ERR(new_root);
743 		btrfs_abort_transaction(trans, ret);
744 		goto out;
745 	}
746 	/* anon_dev is owned by new_root now. */
747 	anon_dev = 0;
748 	BTRFS_I(new_inode_args.inode)->root = new_root;
749 	/* ... and new_root is owned by new_inode_args.inode now. */
750 
751 	ret = btrfs_record_root_in_trans(trans, new_root);
752 	if (ret) {
753 		btrfs_abort_transaction(trans, ret);
754 		goto out;
755 	}
756 
757 	ret = btrfs_uuid_tree_add(trans, root_item->uuid,
758 				  BTRFS_UUID_KEY_SUBVOL, objectid);
759 	if (ret) {
760 		btrfs_abort_transaction(trans, ret);
761 		goto out;
762 	}
763 
764 	ret = btrfs_create_new_inode(trans, &new_inode_args);
765 	if (ret) {
766 		btrfs_abort_transaction(trans, ret);
767 		goto out;
768 	}
769 
770 	d_instantiate_new(dentry, new_inode_args.inode);
771 	new_inode_args.inode = NULL;
772 
773 out:
774 	trans->block_rsv = NULL;
775 	trans->bytes_reserved = 0;
776 	btrfs_end_transaction(trans);
777 out_release_rsv:
778 	btrfs_block_rsv_release(fs_info, &block_rsv, (u64)-1, NULL);
779 	if (qgroup_reserved)
780 		btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
781 out_new_inode_args:
782 	btrfs_new_inode_args_destroy(&new_inode_args);
783 out_inode:
784 	iput(new_inode_args.inode);
785 out_anon_dev:
786 	if (anon_dev)
787 		free_anon_bdev(anon_dev);
788 out_root_item:
789 	kfree(root_item);
790 	return ret;
791 }
792 
793 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
794 			   struct dentry *dentry, bool readonly,
795 			   struct btrfs_qgroup_inherit *inherit)
796 {
797 	struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
798 	struct inode *inode;
799 	struct btrfs_pending_snapshot *pending_snapshot;
800 	unsigned int trans_num_items;
801 	struct btrfs_trans_handle *trans;
802 	struct btrfs_block_rsv *block_rsv;
803 	u64 qgroup_reserved = 0;
804 	int ret;
805 
806 	/* We do not support snapshotting right now. */
807 	if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
808 		btrfs_warn(fs_info,
809 			   "extent tree v2 doesn't support snapshotting yet");
810 		return -EOPNOTSUPP;
811 	}
812 
813 	if (btrfs_root_refs(&root->root_item) == 0)
814 		return -ENOENT;
815 
816 	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
817 		return -EINVAL;
818 
819 	if (atomic_read(&root->nr_swapfiles)) {
820 		btrfs_warn(fs_info,
821 			   "cannot snapshot subvolume with active swapfile");
822 		return -ETXTBSY;
823 	}
824 
825 	pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
826 	if (!pending_snapshot)
827 		return -ENOMEM;
828 
829 	ret = get_anon_bdev(&pending_snapshot->anon_dev);
830 	if (ret < 0)
831 		goto free_pending;
832 	pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item),
833 			GFP_KERNEL);
834 	pending_snapshot->path = btrfs_alloc_path();
835 	if (!pending_snapshot->root_item || !pending_snapshot->path) {
836 		ret = -ENOMEM;
837 		goto free_pending;
838 	}
839 
840 	block_rsv = &pending_snapshot->block_rsv;
841 	btrfs_init_block_rsv(block_rsv, BTRFS_BLOCK_RSV_TEMP);
842 	/*
843 	 * 1 to add dir item
844 	 * 1 to add dir index
845 	 * 1 to update parent inode item
846 	 */
847 	trans_num_items = create_subvol_num_items(inherit) + 3;
848 	ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root, block_rsv,
849 					       trans_num_items, false);
850 	if (ret)
851 		goto free_pending;
852 	qgroup_reserved = block_rsv->qgroup_rsv_reserved;
853 
854 	pending_snapshot->dentry = dentry;
855 	pending_snapshot->root = root;
856 	pending_snapshot->readonly = readonly;
857 	pending_snapshot->dir = dir;
858 	pending_snapshot->inherit = inherit;
859 
860 	trans = btrfs_start_transaction(root, 0);
861 	if (IS_ERR(trans)) {
862 		ret = PTR_ERR(trans);
863 		goto fail;
864 	}
865 	ret = btrfs_record_root_in_trans(trans, BTRFS_I(dir)->root);
866 	if (ret) {
867 		btrfs_end_transaction(trans);
868 		goto fail;
869 	}
870 	btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
871 	qgroup_reserved = 0;
872 
873 	trans->pending_snapshot = pending_snapshot;
874 
875 	ret = btrfs_commit_transaction(trans);
876 	if (ret)
877 		goto fail;
878 
879 	ret = pending_snapshot->error;
880 	if (ret)
881 		goto fail;
882 
883 	ret = btrfs_orphan_cleanup(pending_snapshot->snap);
884 	if (ret)
885 		goto fail;
886 
887 	inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
888 	if (IS_ERR(inode)) {
889 		ret = PTR_ERR(inode);
890 		goto fail;
891 	}
892 
893 	d_instantiate(dentry, inode);
894 	ret = 0;
895 	pending_snapshot->anon_dev = 0;
896 fail:
897 	/* Prevent double freeing of anon_dev */
898 	if (ret && pending_snapshot->snap)
899 		pending_snapshot->snap->anon_dev = 0;
900 	btrfs_put_root(pending_snapshot->snap);
901 	btrfs_block_rsv_release(fs_info, block_rsv, (u64)-1, NULL);
902 	if (qgroup_reserved)
903 		btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
904 free_pending:
905 	if (pending_snapshot->anon_dev)
906 		free_anon_bdev(pending_snapshot->anon_dev);
907 	kfree(pending_snapshot->root_item);
908 	btrfs_free_path(pending_snapshot->path);
909 	kfree(pending_snapshot);
910 
911 	return ret;
912 }
913 
914 /*  copy of may_delete in fs/namei.c()
915  *	Check whether we can remove a link victim from directory dir, check
916  *  whether the type of victim is right.
917  *  1. We can't do it if dir is read-only (done in permission())
918  *  2. We should have write and exec permissions on dir
919  *  3. We can't remove anything from append-only dir
920  *  4. We can't do anything with immutable dir (done in permission())
921  *  5. If the sticky bit on dir is set we should either
922  *	a. be owner of dir, or
923  *	b. be owner of victim, or
924  *	c. have CAP_FOWNER capability
925  *  6. If the victim is append-only or immutable we can't do anything with
926  *     links pointing to it.
927  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
928  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
929  *  9. We can't remove a root or mountpoint.
930  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
931  *     nfs_async_unlink().
932  */
933 
934 static int btrfs_may_delete(struct mnt_idmap *idmap,
935 			    struct inode *dir, struct dentry *victim, int isdir)
936 {
937 	int error;
938 
939 	if (d_really_is_negative(victim))
940 		return -ENOENT;
941 
942 	/* The @victim is not inside @dir. */
943 	if (d_inode(victim->d_parent) != dir)
944 		return -EINVAL;
945 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
946 
947 	error = inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
948 	if (error)
949 		return error;
950 	if (IS_APPEND(dir))
951 		return -EPERM;
952 	if (check_sticky(idmap, dir, d_inode(victim)) ||
953 	    IS_APPEND(d_inode(victim)) || IS_IMMUTABLE(d_inode(victim)) ||
954 	    IS_SWAPFILE(d_inode(victim)))
955 		return -EPERM;
956 	if (isdir) {
957 		if (!d_is_dir(victim))
958 			return -ENOTDIR;
959 		if (IS_ROOT(victim))
960 			return -EBUSY;
961 	} else if (d_is_dir(victim))
962 		return -EISDIR;
963 	if (IS_DEADDIR(dir))
964 		return -ENOENT;
965 	if (victim->d_flags & DCACHE_NFSFS_RENAMED)
966 		return -EBUSY;
967 	return 0;
968 }
969 
970 /* copy of may_create in fs/namei.c() */
971 static inline int btrfs_may_create(struct mnt_idmap *idmap,
972 				   struct inode *dir, struct dentry *child)
973 {
974 	if (d_really_is_positive(child))
975 		return -EEXIST;
976 	if (IS_DEADDIR(dir))
977 		return -ENOENT;
978 	if (!fsuidgid_has_mapping(dir->i_sb, idmap))
979 		return -EOVERFLOW;
980 	return inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
981 }
982 
983 /*
984  * Create a new subvolume below @parent.  This is largely modeled after
985  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
986  * inside this filesystem so it's quite a bit simpler.
987  */
988 static noinline int btrfs_mksubvol(const struct path *parent,
989 				   struct mnt_idmap *idmap,
990 				   const char *name, int namelen,
991 				   struct btrfs_root *snap_src,
992 				   bool readonly,
993 				   struct btrfs_qgroup_inherit *inherit)
994 {
995 	struct inode *dir = d_inode(parent->dentry);
996 	struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
997 	struct dentry *dentry;
998 	struct fscrypt_str name_str = FSTR_INIT((char *)name, namelen);
999 	int error;
1000 
1001 	error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
1002 	if (error == -EINTR)
1003 		return error;
1004 
1005 	dentry = lookup_one(idmap, name, parent->dentry, namelen);
1006 	error = PTR_ERR(dentry);
1007 	if (IS_ERR(dentry))
1008 		goto out_unlock;
1009 
1010 	error = btrfs_may_create(idmap, dir, dentry);
1011 	if (error)
1012 		goto out_dput;
1013 
1014 	/*
1015 	 * even if this name doesn't exist, we may get hash collisions.
1016 	 * check for them now when we can safely fail
1017 	 */
1018 	error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
1019 					       dir->i_ino, &name_str);
1020 	if (error)
1021 		goto out_dput;
1022 
1023 	down_read(&fs_info->subvol_sem);
1024 
1025 	if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
1026 		goto out_up_read;
1027 
1028 	if (snap_src)
1029 		error = create_snapshot(snap_src, dir, dentry, readonly, inherit);
1030 	else
1031 		error = create_subvol(idmap, dir, dentry, inherit);
1032 
1033 	if (!error)
1034 		fsnotify_mkdir(dir, dentry);
1035 out_up_read:
1036 	up_read(&fs_info->subvol_sem);
1037 out_dput:
1038 	dput(dentry);
1039 out_unlock:
1040 	btrfs_inode_unlock(BTRFS_I(dir), 0);
1041 	return error;
1042 }
1043 
1044 static noinline int btrfs_mksnapshot(const struct path *parent,
1045 				   struct mnt_idmap *idmap,
1046 				   const char *name, int namelen,
1047 				   struct btrfs_root *root,
1048 				   bool readonly,
1049 				   struct btrfs_qgroup_inherit *inherit)
1050 {
1051 	int ret;
1052 	bool snapshot_force_cow = false;
1053 
1054 	/*
1055 	 * Force new buffered writes to reserve space even when NOCOW is
1056 	 * possible. This is to avoid later writeback (running dealloc) to
1057 	 * fallback to COW mode and unexpectedly fail with ENOSPC.
1058 	 */
1059 	btrfs_drew_read_lock(&root->snapshot_lock);
1060 
1061 	ret = btrfs_start_delalloc_snapshot(root, false);
1062 	if (ret)
1063 		goto out;
1064 
1065 	/*
1066 	 * All previous writes have started writeback in NOCOW mode, so now
1067 	 * we force future writes to fallback to COW mode during snapshot
1068 	 * creation.
1069 	 */
1070 	atomic_inc(&root->snapshot_force_cow);
1071 	snapshot_force_cow = true;
1072 
1073 	btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
1074 
1075 	ret = btrfs_mksubvol(parent, idmap, name, namelen,
1076 			     root, readonly, inherit);
1077 out:
1078 	if (snapshot_force_cow)
1079 		atomic_dec(&root->snapshot_force_cow);
1080 	btrfs_drew_read_unlock(&root->snapshot_lock);
1081 	return ret;
1082 }
1083 
1084 /*
1085  * Try to start exclusive operation @type or cancel it if it's running.
1086  *
1087  * Return:
1088  *   0        - normal mode, newly claimed op started
1089  *  >0        - normal mode, something else is running,
1090  *              return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS to user space
1091  * ECANCELED  - cancel mode, successful cancel
1092  * ENOTCONN   - cancel mode, operation not running anymore
1093  */
1094 static int exclop_start_or_cancel_reloc(struct btrfs_fs_info *fs_info,
1095 			enum btrfs_exclusive_operation type, bool cancel)
1096 {
1097 	if (!cancel) {
1098 		/* Start normal op */
1099 		if (!btrfs_exclop_start(fs_info, type))
1100 			return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1101 		/* Exclusive operation is now claimed */
1102 		return 0;
1103 	}
1104 
1105 	/* Cancel running op */
1106 	if (btrfs_exclop_start_try_lock(fs_info, type)) {
1107 		/*
1108 		 * This blocks any exclop finish from setting it to NONE, so we
1109 		 * request cancellation. Either it runs and we will wait for it,
1110 		 * or it has finished and no waiting will happen.
1111 		 */
1112 		atomic_inc(&fs_info->reloc_cancel_req);
1113 		btrfs_exclop_start_unlock(fs_info);
1114 
1115 		if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
1116 			wait_on_bit(&fs_info->flags, BTRFS_FS_RELOC_RUNNING,
1117 				    TASK_INTERRUPTIBLE);
1118 
1119 		return -ECANCELED;
1120 	}
1121 
1122 	/* Something else is running or none */
1123 	return -ENOTCONN;
1124 }
1125 
1126 static noinline int btrfs_ioctl_resize(struct file *file,
1127 					void __user *arg)
1128 {
1129 	BTRFS_DEV_LOOKUP_ARGS(args);
1130 	struct inode *inode = file_inode(file);
1131 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1132 	u64 new_size;
1133 	u64 old_size;
1134 	u64 devid = 1;
1135 	struct btrfs_root *root = BTRFS_I(inode)->root;
1136 	struct btrfs_ioctl_vol_args *vol_args;
1137 	struct btrfs_trans_handle *trans;
1138 	struct btrfs_device *device = NULL;
1139 	char *sizestr;
1140 	char *retptr;
1141 	char *devstr = NULL;
1142 	int ret = 0;
1143 	int mod = 0;
1144 	bool cancel;
1145 
1146 	if (!capable(CAP_SYS_ADMIN))
1147 		return -EPERM;
1148 
1149 	ret = mnt_want_write_file(file);
1150 	if (ret)
1151 		return ret;
1152 
1153 	/*
1154 	 * Read the arguments before checking exclusivity to be able to
1155 	 * distinguish regular resize and cancel
1156 	 */
1157 	vol_args = memdup_user(arg, sizeof(*vol_args));
1158 	if (IS_ERR(vol_args)) {
1159 		ret = PTR_ERR(vol_args);
1160 		goto out_drop;
1161 	}
1162 	ret = btrfs_check_ioctl_vol_args_path(vol_args);
1163 	if (ret < 0)
1164 		goto out_free;
1165 
1166 	sizestr = vol_args->name;
1167 	cancel = (strcmp("cancel", sizestr) == 0);
1168 	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_RESIZE, cancel);
1169 	if (ret)
1170 		goto out_free;
1171 	/* Exclusive operation is now claimed */
1172 
1173 	devstr = strchr(sizestr, ':');
1174 	if (devstr) {
1175 		sizestr = devstr + 1;
1176 		*devstr = '\0';
1177 		devstr = vol_args->name;
1178 		ret = kstrtoull(devstr, 10, &devid);
1179 		if (ret)
1180 			goto out_finish;
1181 		if (!devid) {
1182 			ret = -EINVAL;
1183 			goto out_finish;
1184 		}
1185 		btrfs_info(fs_info, "resizing devid %llu", devid);
1186 	}
1187 
1188 	args.devid = devid;
1189 	device = btrfs_find_device(fs_info->fs_devices, &args);
1190 	if (!device) {
1191 		btrfs_info(fs_info, "resizer unable to find device %llu",
1192 			   devid);
1193 		ret = -ENODEV;
1194 		goto out_finish;
1195 	}
1196 
1197 	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
1198 		btrfs_info(fs_info,
1199 			   "resizer unable to apply on readonly device %llu",
1200 		       devid);
1201 		ret = -EPERM;
1202 		goto out_finish;
1203 	}
1204 
1205 	if (!strcmp(sizestr, "max"))
1206 		new_size = bdev_nr_bytes(device->bdev);
1207 	else {
1208 		if (sizestr[0] == '-') {
1209 			mod = -1;
1210 			sizestr++;
1211 		} else if (sizestr[0] == '+') {
1212 			mod = 1;
1213 			sizestr++;
1214 		}
1215 		new_size = memparse(sizestr, &retptr);
1216 		if (*retptr != '\0' || new_size == 0) {
1217 			ret = -EINVAL;
1218 			goto out_finish;
1219 		}
1220 	}
1221 
1222 	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
1223 		ret = -EPERM;
1224 		goto out_finish;
1225 	}
1226 
1227 	old_size = btrfs_device_get_total_bytes(device);
1228 
1229 	if (mod < 0) {
1230 		if (new_size > old_size) {
1231 			ret = -EINVAL;
1232 			goto out_finish;
1233 		}
1234 		new_size = old_size - new_size;
1235 	} else if (mod > 0) {
1236 		if (new_size > ULLONG_MAX - old_size) {
1237 			ret = -ERANGE;
1238 			goto out_finish;
1239 		}
1240 		new_size = old_size + new_size;
1241 	}
1242 
1243 	if (new_size < SZ_256M) {
1244 		ret = -EINVAL;
1245 		goto out_finish;
1246 	}
1247 	if (new_size > bdev_nr_bytes(device->bdev)) {
1248 		ret = -EFBIG;
1249 		goto out_finish;
1250 	}
1251 
1252 	new_size = round_down(new_size, fs_info->sectorsize);
1253 
1254 	if (new_size > old_size) {
1255 		trans = btrfs_start_transaction(root, 0);
1256 		if (IS_ERR(trans)) {
1257 			ret = PTR_ERR(trans);
1258 			goto out_finish;
1259 		}
1260 		ret = btrfs_grow_device(trans, device, new_size);
1261 		btrfs_commit_transaction(trans);
1262 	} else if (new_size < old_size) {
1263 		ret = btrfs_shrink_device(device, new_size);
1264 	} /* equal, nothing need to do */
1265 
1266 	if (ret == 0 && new_size != old_size)
1267 		btrfs_info_in_rcu(fs_info,
1268 			"resize device %s (devid %llu) from %llu to %llu",
1269 			btrfs_dev_name(device), device->devid,
1270 			old_size, new_size);
1271 out_finish:
1272 	btrfs_exclop_finish(fs_info);
1273 out_free:
1274 	kfree(vol_args);
1275 out_drop:
1276 	mnt_drop_write_file(file);
1277 	return ret;
1278 }
1279 
1280 static noinline int __btrfs_ioctl_snap_create(struct file *file,
1281 				struct mnt_idmap *idmap,
1282 				const char *name, unsigned long fd, int subvol,
1283 				bool readonly,
1284 				struct btrfs_qgroup_inherit *inherit)
1285 {
1286 	int namelen;
1287 	int ret = 0;
1288 
1289 	if (!S_ISDIR(file_inode(file)->i_mode))
1290 		return -ENOTDIR;
1291 
1292 	ret = mnt_want_write_file(file);
1293 	if (ret)
1294 		goto out;
1295 
1296 	namelen = strlen(name);
1297 	if (strchr(name, '/')) {
1298 		ret = -EINVAL;
1299 		goto out_drop_write;
1300 	}
1301 
1302 	if (name[0] == '.' &&
1303 	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1304 		ret = -EEXIST;
1305 		goto out_drop_write;
1306 	}
1307 
1308 	if (subvol) {
1309 		ret = btrfs_mksubvol(&file->f_path, idmap, name,
1310 				     namelen, NULL, readonly, inherit);
1311 	} else {
1312 		struct fd src = fdget(fd);
1313 		struct inode *src_inode;
1314 		if (!src.file) {
1315 			ret = -EINVAL;
1316 			goto out_drop_write;
1317 		}
1318 
1319 		src_inode = file_inode(src.file);
1320 		if (src_inode->i_sb != file_inode(file)->i_sb) {
1321 			btrfs_info(BTRFS_I(file_inode(file))->root->fs_info,
1322 				   "Snapshot src from another FS");
1323 			ret = -EXDEV;
1324 		} else if (!inode_owner_or_capable(idmap, src_inode)) {
1325 			/*
1326 			 * Subvolume creation is not restricted, but snapshots
1327 			 * are limited to own subvolumes only
1328 			 */
1329 			ret = -EPERM;
1330 		} else if (btrfs_ino(BTRFS_I(src_inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1331 			/*
1332 			 * Snapshots must be made with the src_inode referring
1333 			 * to the subvolume inode, otherwise the permission
1334 			 * checking above is useless because we may have
1335 			 * permission on a lower directory but not the subvol
1336 			 * itself.
1337 			 */
1338 			ret = -EINVAL;
1339 		} else {
1340 			ret = btrfs_mksnapshot(&file->f_path, idmap,
1341 					       name, namelen,
1342 					       BTRFS_I(src_inode)->root,
1343 					       readonly, inherit);
1344 		}
1345 		fdput(src);
1346 	}
1347 out_drop_write:
1348 	mnt_drop_write_file(file);
1349 out:
1350 	return ret;
1351 }
1352 
1353 static noinline int btrfs_ioctl_snap_create(struct file *file,
1354 					    void __user *arg, int subvol)
1355 {
1356 	struct btrfs_ioctl_vol_args *vol_args;
1357 	int ret;
1358 
1359 	if (!S_ISDIR(file_inode(file)->i_mode))
1360 		return -ENOTDIR;
1361 
1362 	vol_args = memdup_user(arg, sizeof(*vol_args));
1363 	if (IS_ERR(vol_args))
1364 		return PTR_ERR(vol_args);
1365 	ret = btrfs_check_ioctl_vol_args_path(vol_args);
1366 	if (ret < 0)
1367 		goto out;
1368 
1369 	ret = __btrfs_ioctl_snap_create(file, file_mnt_idmap(file),
1370 					vol_args->name, vol_args->fd, subvol,
1371 					false, NULL);
1372 
1373 out:
1374 	kfree(vol_args);
1375 	return ret;
1376 }
1377 
1378 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1379 					       void __user *arg, int subvol)
1380 {
1381 	struct btrfs_ioctl_vol_args_v2 *vol_args;
1382 	int ret;
1383 	bool readonly = false;
1384 	struct btrfs_qgroup_inherit *inherit = NULL;
1385 
1386 	if (!S_ISDIR(file_inode(file)->i_mode))
1387 		return -ENOTDIR;
1388 
1389 	vol_args = memdup_user(arg, sizeof(*vol_args));
1390 	if (IS_ERR(vol_args))
1391 		return PTR_ERR(vol_args);
1392 	ret = btrfs_check_ioctl_vol_args2_subvol_name(vol_args);
1393 	if (ret < 0)
1394 		goto free_args;
1395 
1396 	if (vol_args->flags & ~BTRFS_SUBVOL_CREATE_ARGS_MASK) {
1397 		ret = -EOPNOTSUPP;
1398 		goto free_args;
1399 	}
1400 
1401 	if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1402 		readonly = true;
1403 	if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1404 		struct btrfs_fs_info *fs_info = inode_to_fs_info(file_inode(file));
1405 
1406 		if (vol_args->size < sizeof(*inherit) ||
1407 		    vol_args->size > PAGE_SIZE) {
1408 			ret = -EINVAL;
1409 			goto free_args;
1410 		}
1411 		inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1412 		if (IS_ERR(inherit)) {
1413 			ret = PTR_ERR(inherit);
1414 			goto free_args;
1415 		}
1416 
1417 		ret = btrfs_qgroup_check_inherit(fs_info, inherit, vol_args->size);
1418 		if (ret < 0)
1419 			goto free_inherit;
1420 	}
1421 
1422 	ret = __btrfs_ioctl_snap_create(file, file_mnt_idmap(file),
1423 					vol_args->name, vol_args->fd, subvol,
1424 					readonly, inherit);
1425 	if (ret)
1426 		goto free_inherit;
1427 free_inherit:
1428 	kfree(inherit);
1429 free_args:
1430 	kfree(vol_args);
1431 	return ret;
1432 }
1433 
1434 static noinline int btrfs_ioctl_subvol_getflags(struct inode *inode,
1435 						void __user *arg)
1436 {
1437 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1438 	struct btrfs_root *root = BTRFS_I(inode)->root;
1439 	int ret = 0;
1440 	u64 flags = 0;
1441 
1442 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID)
1443 		return -EINVAL;
1444 
1445 	down_read(&fs_info->subvol_sem);
1446 	if (btrfs_root_readonly(root))
1447 		flags |= BTRFS_SUBVOL_RDONLY;
1448 	up_read(&fs_info->subvol_sem);
1449 
1450 	if (copy_to_user(arg, &flags, sizeof(flags)))
1451 		ret = -EFAULT;
1452 
1453 	return ret;
1454 }
1455 
1456 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1457 					      void __user *arg)
1458 {
1459 	struct inode *inode = file_inode(file);
1460 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1461 	struct btrfs_root *root = BTRFS_I(inode)->root;
1462 	struct btrfs_trans_handle *trans;
1463 	u64 root_flags;
1464 	u64 flags;
1465 	int ret = 0;
1466 
1467 	if (!inode_owner_or_capable(file_mnt_idmap(file), inode))
1468 		return -EPERM;
1469 
1470 	ret = mnt_want_write_file(file);
1471 	if (ret)
1472 		goto out;
1473 
1474 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1475 		ret = -EINVAL;
1476 		goto out_drop_write;
1477 	}
1478 
1479 	if (copy_from_user(&flags, arg, sizeof(flags))) {
1480 		ret = -EFAULT;
1481 		goto out_drop_write;
1482 	}
1483 
1484 	if (flags & ~BTRFS_SUBVOL_RDONLY) {
1485 		ret = -EOPNOTSUPP;
1486 		goto out_drop_write;
1487 	}
1488 
1489 	down_write(&fs_info->subvol_sem);
1490 
1491 	/* nothing to do */
1492 	if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1493 		goto out_drop_sem;
1494 
1495 	root_flags = btrfs_root_flags(&root->root_item);
1496 	if (flags & BTRFS_SUBVOL_RDONLY) {
1497 		btrfs_set_root_flags(&root->root_item,
1498 				     root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1499 	} else {
1500 		/*
1501 		 * Block RO -> RW transition if this subvolume is involved in
1502 		 * send
1503 		 */
1504 		spin_lock(&root->root_item_lock);
1505 		if (root->send_in_progress == 0) {
1506 			btrfs_set_root_flags(&root->root_item,
1507 				     root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1508 			spin_unlock(&root->root_item_lock);
1509 		} else {
1510 			spin_unlock(&root->root_item_lock);
1511 			btrfs_warn(fs_info,
1512 				   "Attempt to set subvolume %llu read-write during send",
1513 				   btrfs_root_id(root));
1514 			ret = -EPERM;
1515 			goto out_drop_sem;
1516 		}
1517 	}
1518 
1519 	trans = btrfs_start_transaction(root, 1);
1520 	if (IS_ERR(trans)) {
1521 		ret = PTR_ERR(trans);
1522 		goto out_reset;
1523 	}
1524 
1525 	ret = btrfs_update_root(trans, fs_info->tree_root,
1526 				&root->root_key, &root->root_item);
1527 	if (ret < 0) {
1528 		btrfs_end_transaction(trans);
1529 		goto out_reset;
1530 	}
1531 
1532 	ret = btrfs_commit_transaction(trans);
1533 
1534 out_reset:
1535 	if (ret)
1536 		btrfs_set_root_flags(&root->root_item, root_flags);
1537 out_drop_sem:
1538 	up_write(&fs_info->subvol_sem);
1539 out_drop_write:
1540 	mnt_drop_write_file(file);
1541 out:
1542 	return ret;
1543 }
1544 
1545 static noinline int key_in_sk(struct btrfs_key *key,
1546 			      struct btrfs_ioctl_search_key *sk)
1547 {
1548 	struct btrfs_key test;
1549 	int ret;
1550 
1551 	test.objectid = sk->min_objectid;
1552 	test.type = sk->min_type;
1553 	test.offset = sk->min_offset;
1554 
1555 	ret = btrfs_comp_cpu_keys(key, &test);
1556 	if (ret < 0)
1557 		return 0;
1558 
1559 	test.objectid = sk->max_objectid;
1560 	test.type = sk->max_type;
1561 	test.offset = sk->max_offset;
1562 
1563 	ret = btrfs_comp_cpu_keys(key, &test);
1564 	if (ret > 0)
1565 		return 0;
1566 	return 1;
1567 }
1568 
1569 static noinline int copy_to_sk(struct btrfs_path *path,
1570 			       struct btrfs_key *key,
1571 			       struct btrfs_ioctl_search_key *sk,
1572 			       u64 *buf_size,
1573 			       char __user *ubuf,
1574 			       unsigned long *sk_offset,
1575 			       int *num_found)
1576 {
1577 	u64 found_transid;
1578 	struct extent_buffer *leaf;
1579 	struct btrfs_ioctl_search_header sh;
1580 	struct btrfs_key test;
1581 	unsigned long item_off;
1582 	unsigned long item_len;
1583 	int nritems;
1584 	int i;
1585 	int slot;
1586 	int ret = 0;
1587 
1588 	leaf = path->nodes[0];
1589 	slot = path->slots[0];
1590 	nritems = btrfs_header_nritems(leaf);
1591 
1592 	if (btrfs_header_generation(leaf) > sk->max_transid) {
1593 		i = nritems;
1594 		goto advance_key;
1595 	}
1596 	found_transid = btrfs_header_generation(leaf);
1597 
1598 	for (i = slot; i < nritems; i++) {
1599 		item_off = btrfs_item_ptr_offset(leaf, i);
1600 		item_len = btrfs_item_size(leaf, i);
1601 
1602 		btrfs_item_key_to_cpu(leaf, key, i);
1603 		if (!key_in_sk(key, sk))
1604 			continue;
1605 
1606 		if (sizeof(sh) + item_len > *buf_size) {
1607 			if (*num_found) {
1608 				ret = 1;
1609 				goto out;
1610 			}
1611 
1612 			/*
1613 			 * return one empty item back for v1, which does not
1614 			 * handle -EOVERFLOW
1615 			 */
1616 
1617 			*buf_size = sizeof(sh) + item_len;
1618 			item_len = 0;
1619 			ret = -EOVERFLOW;
1620 		}
1621 
1622 		if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
1623 			ret = 1;
1624 			goto out;
1625 		}
1626 
1627 		sh.objectid = key->objectid;
1628 		sh.offset = key->offset;
1629 		sh.type = key->type;
1630 		sh.len = item_len;
1631 		sh.transid = found_transid;
1632 
1633 		/*
1634 		 * Copy search result header. If we fault then loop again so we
1635 		 * can fault in the pages and -EFAULT there if there's a
1636 		 * problem. Otherwise we'll fault and then copy the buffer in
1637 		 * properly this next time through
1638 		 */
1639 		if (copy_to_user_nofault(ubuf + *sk_offset, &sh, sizeof(sh))) {
1640 			ret = 0;
1641 			goto out;
1642 		}
1643 
1644 		*sk_offset += sizeof(sh);
1645 
1646 		if (item_len) {
1647 			char __user *up = ubuf + *sk_offset;
1648 			/*
1649 			 * Copy the item, same behavior as above, but reset the
1650 			 * * sk_offset so we copy the full thing again.
1651 			 */
1652 			if (read_extent_buffer_to_user_nofault(leaf, up,
1653 						item_off, item_len)) {
1654 				ret = 0;
1655 				*sk_offset -= sizeof(sh);
1656 				goto out;
1657 			}
1658 
1659 			*sk_offset += item_len;
1660 		}
1661 		(*num_found)++;
1662 
1663 		if (ret) /* -EOVERFLOW from above */
1664 			goto out;
1665 
1666 		if (*num_found >= sk->nr_items) {
1667 			ret = 1;
1668 			goto out;
1669 		}
1670 	}
1671 advance_key:
1672 	ret = 0;
1673 	test.objectid = sk->max_objectid;
1674 	test.type = sk->max_type;
1675 	test.offset = sk->max_offset;
1676 	if (btrfs_comp_cpu_keys(key, &test) >= 0)
1677 		ret = 1;
1678 	else if (key->offset < (u64)-1)
1679 		key->offset++;
1680 	else if (key->type < (u8)-1) {
1681 		key->offset = 0;
1682 		key->type++;
1683 	} else if (key->objectid < (u64)-1) {
1684 		key->offset = 0;
1685 		key->type = 0;
1686 		key->objectid++;
1687 	} else
1688 		ret = 1;
1689 out:
1690 	/*
1691 	 *  0: all items from this leaf copied, continue with next
1692 	 *  1: * more items can be copied, but unused buffer is too small
1693 	 *     * all items were found
1694 	 *     Either way, it will stops the loop which iterates to the next
1695 	 *     leaf
1696 	 *  -EOVERFLOW: item was to large for buffer
1697 	 *  -EFAULT: could not copy extent buffer back to userspace
1698 	 */
1699 	return ret;
1700 }
1701 
1702 static noinline int search_ioctl(struct inode *inode,
1703 				 struct btrfs_ioctl_search_key *sk,
1704 				 u64 *buf_size,
1705 				 char __user *ubuf)
1706 {
1707 	struct btrfs_fs_info *info = inode_to_fs_info(inode);
1708 	struct btrfs_root *root;
1709 	struct btrfs_key key;
1710 	struct btrfs_path *path;
1711 	int ret;
1712 	int num_found = 0;
1713 	unsigned long sk_offset = 0;
1714 
1715 	if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
1716 		*buf_size = sizeof(struct btrfs_ioctl_search_header);
1717 		return -EOVERFLOW;
1718 	}
1719 
1720 	path = btrfs_alloc_path();
1721 	if (!path)
1722 		return -ENOMEM;
1723 
1724 	if (sk->tree_id == 0) {
1725 		/* search the root of the inode that was passed */
1726 		root = btrfs_grab_root(BTRFS_I(inode)->root);
1727 	} else {
1728 		root = btrfs_get_fs_root(info, sk->tree_id, true);
1729 		if (IS_ERR(root)) {
1730 			btrfs_free_path(path);
1731 			return PTR_ERR(root);
1732 		}
1733 	}
1734 
1735 	key.objectid = sk->min_objectid;
1736 	key.type = sk->min_type;
1737 	key.offset = sk->min_offset;
1738 
1739 	while (1) {
1740 		ret = -EFAULT;
1741 		/*
1742 		 * Ensure that the whole user buffer is faulted in at sub-page
1743 		 * granularity, otherwise the loop may live-lock.
1744 		 */
1745 		if (fault_in_subpage_writeable(ubuf + sk_offset,
1746 					       *buf_size - sk_offset))
1747 			break;
1748 
1749 		ret = btrfs_search_forward(root, &key, path, sk->min_transid);
1750 		if (ret != 0) {
1751 			if (ret > 0)
1752 				ret = 0;
1753 			goto err;
1754 		}
1755 		ret = copy_to_sk(path, &key, sk, buf_size, ubuf,
1756 				 &sk_offset, &num_found);
1757 		btrfs_release_path(path);
1758 		if (ret)
1759 			break;
1760 
1761 	}
1762 	if (ret > 0)
1763 		ret = 0;
1764 err:
1765 	sk->nr_items = num_found;
1766 	btrfs_put_root(root);
1767 	btrfs_free_path(path);
1768 	return ret;
1769 }
1770 
1771 static noinline int btrfs_ioctl_tree_search(struct inode *inode,
1772 					    void __user *argp)
1773 {
1774 	struct btrfs_ioctl_search_args __user *uargs = argp;
1775 	struct btrfs_ioctl_search_key sk;
1776 	int ret;
1777 	u64 buf_size;
1778 
1779 	if (!capable(CAP_SYS_ADMIN))
1780 		return -EPERM;
1781 
1782 	if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
1783 		return -EFAULT;
1784 
1785 	buf_size = sizeof(uargs->buf);
1786 
1787 	ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
1788 
1789 	/*
1790 	 * In the origin implementation an overflow is handled by returning a
1791 	 * search header with a len of zero, so reset ret.
1792 	 */
1793 	if (ret == -EOVERFLOW)
1794 		ret = 0;
1795 
1796 	if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
1797 		ret = -EFAULT;
1798 	return ret;
1799 }
1800 
1801 static noinline int btrfs_ioctl_tree_search_v2(struct inode *inode,
1802 					       void __user *argp)
1803 {
1804 	struct btrfs_ioctl_search_args_v2 __user *uarg = argp;
1805 	struct btrfs_ioctl_search_args_v2 args;
1806 	int ret;
1807 	u64 buf_size;
1808 	const u64 buf_limit = SZ_16M;
1809 
1810 	if (!capable(CAP_SYS_ADMIN))
1811 		return -EPERM;
1812 
1813 	/* copy search header and buffer size */
1814 	if (copy_from_user(&args, uarg, sizeof(args)))
1815 		return -EFAULT;
1816 
1817 	buf_size = args.buf_size;
1818 
1819 	/* limit result size to 16MB */
1820 	if (buf_size > buf_limit)
1821 		buf_size = buf_limit;
1822 
1823 	ret = search_ioctl(inode, &args.key, &buf_size,
1824 			   (char __user *)(&uarg->buf[0]));
1825 	if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
1826 		ret = -EFAULT;
1827 	else if (ret == -EOVERFLOW &&
1828 		copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
1829 		ret = -EFAULT;
1830 
1831 	return ret;
1832 }
1833 
1834 /*
1835  * Search INODE_REFs to identify path name of 'dirid' directory
1836  * in a 'tree_id' tree. and sets path name to 'name'.
1837  */
1838 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
1839 				u64 tree_id, u64 dirid, char *name)
1840 {
1841 	struct btrfs_root *root;
1842 	struct btrfs_key key;
1843 	char *ptr;
1844 	int ret = -1;
1845 	int slot;
1846 	int len;
1847 	int total_len = 0;
1848 	struct btrfs_inode_ref *iref;
1849 	struct extent_buffer *l;
1850 	struct btrfs_path *path;
1851 
1852 	if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
1853 		name[0]='\0';
1854 		return 0;
1855 	}
1856 
1857 	path = btrfs_alloc_path();
1858 	if (!path)
1859 		return -ENOMEM;
1860 
1861 	ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX - 1];
1862 
1863 	root = btrfs_get_fs_root(info, tree_id, true);
1864 	if (IS_ERR(root)) {
1865 		ret = PTR_ERR(root);
1866 		root = NULL;
1867 		goto out;
1868 	}
1869 
1870 	key.objectid = dirid;
1871 	key.type = BTRFS_INODE_REF_KEY;
1872 	key.offset = (u64)-1;
1873 
1874 	while (1) {
1875 		ret = btrfs_search_backwards(root, &key, path);
1876 		if (ret < 0)
1877 			goto out;
1878 		else if (ret > 0) {
1879 			ret = -ENOENT;
1880 			goto out;
1881 		}
1882 
1883 		l = path->nodes[0];
1884 		slot = path->slots[0];
1885 
1886 		iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
1887 		len = btrfs_inode_ref_name_len(l, iref);
1888 		ptr -= len + 1;
1889 		total_len += len + 1;
1890 		if (ptr < name) {
1891 			ret = -ENAMETOOLONG;
1892 			goto out;
1893 		}
1894 
1895 		*(ptr + len) = '/';
1896 		read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
1897 
1898 		if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
1899 			break;
1900 
1901 		btrfs_release_path(path);
1902 		key.objectid = key.offset;
1903 		key.offset = (u64)-1;
1904 		dirid = key.objectid;
1905 	}
1906 	memmove(name, ptr, total_len);
1907 	name[total_len] = '\0';
1908 	ret = 0;
1909 out:
1910 	btrfs_put_root(root);
1911 	btrfs_free_path(path);
1912 	return ret;
1913 }
1914 
1915 static int btrfs_search_path_in_tree_user(struct mnt_idmap *idmap,
1916 				struct inode *inode,
1917 				struct btrfs_ioctl_ino_lookup_user_args *args)
1918 {
1919 	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1920 	struct super_block *sb = inode->i_sb;
1921 	struct btrfs_key upper_limit = BTRFS_I(inode)->location;
1922 	u64 treeid = btrfs_root_id(BTRFS_I(inode)->root);
1923 	u64 dirid = args->dirid;
1924 	unsigned long item_off;
1925 	unsigned long item_len;
1926 	struct btrfs_inode_ref *iref;
1927 	struct btrfs_root_ref *rref;
1928 	struct btrfs_root *root = NULL;
1929 	struct btrfs_path *path;
1930 	struct btrfs_key key, key2;
1931 	struct extent_buffer *leaf;
1932 	struct inode *temp_inode;
1933 	char *ptr;
1934 	int slot;
1935 	int len;
1936 	int total_len = 0;
1937 	int ret;
1938 
1939 	path = btrfs_alloc_path();
1940 	if (!path)
1941 		return -ENOMEM;
1942 
1943 	/*
1944 	 * If the bottom subvolume does not exist directly under upper_limit,
1945 	 * construct the path in from the bottom up.
1946 	 */
1947 	if (dirid != upper_limit.objectid) {
1948 		ptr = &args->path[BTRFS_INO_LOOKUP_USER_PATH_MAX - 1];
1949 
1950 		root = btrfs_get_fs_root(fs_info, treeid, true);
1951 		if (IS_ERR(root)) {
1952 			ret = PTR_ERR(root);
1953 			goto out;
1954 		}
1955 
1956 		key.objectid = dirid;
1957 		key.type = BTRFS_INODE_REF_KEY;
1958 		key.offset = (u64)-1;
1959 		while (1) {
1960 			ret = btrfs_search_backwards(root, &key, path);
1961 			if (ret < 0)
1962 				goto out_put;
1963 			else if (ret > 0) {
1964 				ret = -ENOENT;
1965 				goto out_put;
1966 			}
1967 
1968 			leaf = path->nodes[0];
1969 			slot = path->slots[0];
1970 
1971 			iref = btrfs_item_ptr(leaf, slot, struct btrfs_inode_ref);
1972 			len = btrfs_inode_ref_name_len(leaf, iref);
1973 			ptr -= len + 1;
1974 			total_len += len + 1;
1975 			if (ptr < args->path) {
1976 				ret = -ENAMETOOLONG;
1977 				goto out_put;
1978 			}
1979 
1980 			*(ptr + len) = '/';
1981 			read_extent_buffer(leaf, ptr,
1982 					(unsigned long)(iref + 1), len);
1983 
1984 			/* Check the read+exec permission of this directory */
1985 			ret = btrfs_previous_item(root, path, dirid,
1986 						  BTRFS_INODE_ITEM_KEY);
1987 			if (ret < 0) {
1988 				goto out_put;
1989 			} else if (ret > 0) {
1990 				ret = -ENOENT;
1991 				goto out_put;
1992 			}
1993 
1994 			leaf = path->nodes[0];
1995 			slot = path->slots[0];
1996 			btrfs_item_key_to_cpu(leaf, &key2, slot);
1997 			if (key2.objectid != dirid) {
1998 				ret = -ENOENT;
1999 				goto out_put;
2000 			}
2001 
2002 			/*
2003 			 * We don't need the path anymore, so release it and
2004 			 * avoid deadlocks and lockdep warnings in case
2005 			 * btrfs_iget() needs to lookup the inode from its root
2006 			 * btree and lock the same leaf.
2007 			 */
2008 			btrfs_release_path(path);
2009 			temp_inode = btrfs_iget(sb, key2.objectid, root);
2010 			if (IS_ERR(temp_inode)) {
2011 				ret = PTR_ERR(temp_inode);
2012 				goto out_put;
2013 			}
2014 			ret = inode_permission(idmap, temp_inode,
2015 					       MAY_READ | MAY_EXEC);
2016 			iput(temp_inode);
2017 			if (ret) {
2018 				ret = -EACCES;
2019 				goto out_put;
2020 			}
2021 
2022 			if (key.offset == upper_limit.objectid)
2023 				break;
2024 			if (key.objectid == BTRFS_FIRST_FREE_OBJECTID) {
2025 				ret = -EACCES;
2026 				goto out_put;
2027 			}
2028 
2029 			key.objectid = key.offset;
2030 			key.offset = (u64)-1;
2031 			dirid = key.objectid;
2032 		}
2033 
2034 		memmove(args->path, ptr, total_len);
2035 		args->path[total_len] = '\0';
2036 		btrfs_put_root(root);
2037 		root = NULL;
2038 		btrfs_release_path(path);
2039 	}
2040 
2041 	/* Get the bottom subvolume's name from ROOT_REF */
2042 	key.objectid = treeid;
2043 	key.type = BTRFS_ROOT_REF_KEY;
2044 	key.offset = args->treeid;
2045 	ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2046 	if (ret < 0) {
2047 		goto out;
2048 	} else if (ret > 0) {
2049 		ret = -ENOENT;
2050 		goto out;
2051 	}
2052 
2053 	leaf = path->nodes[0];
2054 	slot = path->slots[0];
2055 	btrfs_item_key_to_cpu(leaf, &key, slot);
2056 
2057 	item_off = btrfs_item_ptr_offset(leaf, slot);
2058 	item_len = btrfs_item_size(leaf, slot);
2059 	/* Check if dirid in ROOT_REF corresponds to passed dirid */
2060 	rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2061 	if (args->dirid != btrfs_root_ref_dirid(leaf, rref)) {
2062 		ret = -EINVAL;
2063 		goto out;
2064 	}
2065 
2066 	/* Copy subvolume's name */
2067 	item_off += sizeof(struct btrfs_root_ref);
2068 	item_len -= sizeof(struct btrfs_root_ref);
2069 	read_extent_buffer(leaf, args->name, item_off, item_len);
2070 	args->name[item_len] = 0;
2071 
2072 out_put:
2073 	btrfs_put_root(root);
2074 out:
2075 	btrfs_free_path(path);
2076 	return ret;
2077 }
2078 
2079 static noinline int btrfs_ioctl_ino_lookup(struct btrfs_root *root,
2080 					   void __user *argp)
2081 {
2082 	struct btrfs_ioctl_ino_lookup_args *args;
2083 	int ret = 0;
2084 
2085 	args = memdup_user(argp, sizeof(*args));
2086 	if (IS_ERR(args))
2087 		return PTR_ERR(args);
2088 
2089 	/*
2090 	 * Unprivileged query to obtain the containing subvolume root id. The
2091 	 * path is reset so it's consistent with btrfs_search_path_in_tree.
2092 	 */
2093 	if (args->treeid == 0)
2094 		args->treeid = btrfs_root_id(root);
2095 
2096 	if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2097 		args->name[0] = 0;
2098 		goto out;
2099 	}
2100 
2101 	if (!capable(CAP_SYS_ADMIN)) {
2102 		ret = -EPERM;
2103 		goto out;
2104 	}
2105 
2106 	ret = btrfs_search_path_in_tree(root->fs_info,
2107 					args->treeid, args->objectid,
2108 					args->name);
2109 
2110 out:
2111 	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2112 		ret = -EFAULT;
2113 
2114 	kfree(args);
2115 	return ret;
2116 }
2117 
2118 /*
2119  * Version of ino_lookup ioctl (unprivileged)
2120  *
2121  * The main differences from ino_lookup ioctl are:
2122  *
2123  *   1. Read + Exec permission will be checked using inode_permission() during
2124  *      path construction. -EACCES will be returned in case of failure.
2125  *   2. Path construction will be stopped at the inode number which corresponds
2126  *      to the fd with which this ioctl is called. If constructed path does not
2127  *      exist under fd's inode, -EACCES will be returned.
2128  *   3. The name of bottom subvolume is also searched and filled.
2129  */
2130 static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp)
2131 {
2132 	struct btrfs_ioctl_ino_lookup_user_args *args;
2133 	struct inode *inode;
2134 	int ret;
2135 
2136 	args = memdup_user(argp, sizeof(*args));
2137 	if (IS_ERR(args))
2138 		return PTR_ERR(args);
2139 
2140 	inode = file_inode(file);
2141 
2142 	if (args->dirid == BTRFS_FIRST_FREE_OBJECTID &&
2143 	    BTRFS_I(inode)->location.objectid != BTRFS_FIRST_FREE_OBJECTID) {
2144 		/*
2145 		 * The subvolume does not exist under fd with which this is
2146 		 * called
2147 		 */
2148 		kfree(args);
2149 		return -EACCES;
2150 	}
2151 
2152 	ret = btrfs_search_path_in_tree_user(file_mnt_idmap(file), inode, args);
2153 
2154 	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2155 		ret = -EFAULT;
2156 
2157 	kfree(args);
2158 	return ret;
2159 }
2160 
2161 /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */
2162 static int btrfs_ioctl_get_subvol_info(struct inode *inode, void __user *argp)
2163 {
2164 	struct btrfs_ioctl_get_subvol_info_args *subvol_info;
2165 	struct btrfs_fs_info *fs_info;
2166 	struct btrfs_root *root;
2167 	struct btrfs_path *path;
2168 	struct btrfs_key key;
2169 	struct btrfs_root_item *root_item;
2170 	struct btrfs_root_ref *rref;
2171 	struct extent_buffer *leaf;
2172 	unsigned long item_off;
2173 	unsigned long item_len;
2174 	int slot;
2175 	int ret = 0;
2176 
2177 	path = btrfs_alloc_path();
2178 	if (!path)
2179 		return -ENOMEM;
2180 
2181 	subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL);
2182 	if (!subvol_info) {
2183 		btrfs_free_path(path);
2184 		return -ENOMEM;
2185 	}
2186 
2187 	fs_info = BTRFS_I(inode)->root->fs_info;
2188 
2189 	/* Get root_item of inode's subvolume */
2190 	key.objectid = btrfs_root_id(BTRFS_I(inode)->root);
2191 	root = btrfs_get_fs_root(fs_info, key.objectid, true);
2192 	if (IS_ERR(root)) {
2193 		ret = PTR_ERR(root);
2194 		goto out_free;
2195 	}
2196 	root_item = &root->root_item;
2197 
2198 	subvol_info->treeid = key.objectid;
2199 
2200 	subvol_info->generation = btrfs_root_generation(root_item);
2201 	subvol_info->flags = btrfs_root_flags(root_item);
2202 
2203 	memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE);
2204 	memcpy(subvol_info->parent_uuid, root_item->parent_uuid,
2205 						    BTRFS_UUID_SIZE);
2206 	memcpy(subvol_info->received_uuid, root_item->received_uuid,
2207 						    BTRFS_UUID_SIZE);
2208 
2209 	subvol_info->ctransid = btrfs_root_ctransid(root_item);
2210 	subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
2211 	subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
2212 
2213 	subvol_info->otransid = btrfs_root_otransid(root_item);
2214 	subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
2215 	subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
2216 
2217 	subvol_info->stransid = btrfs_root_stransid(root_item);
2218 	subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
2219 	subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
2220 
2221 	subvol_info->rtransid = btrfs_root_rtransid(root_item);
2222 	subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
2223 	subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
2224 
2225 	if (key.objectid != BTRFS_FS_TREE_OBJECTID) {
2226 		/* Search root tree for ROOT_BACKREF of this subvolume */
2227 		key.type = BTRFS_ROOT_BACKREF_KEY;
2228 		key.offset = 0;
2229 		ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2230 		if (ret < 0) {
2231 			goto out;
2232 		} else if (path->slots[0] >=
2233 			   btrfs_header_nritems(path->nodes[0])) {
2234 			ret = btrfs_next_leaf(fs_info->tree_root, path);
2235 			if (ret < 0) {
2236 				goto out;
2237 			} else if (ret > 0) {
2238 				ret = -EUCLEAN;
2239 				goto out;
2240 			}
2241 		}
2242 
2243 		leaf = path->nodes[0];
2244 		slot = path->slots[0];
2245 		btrfs_item_key_to_cpu(leaf, &key, slot);
2246 		if (key.objectid == subvol_info->treeid &&
2247 		    key.type == BTRFS_ROOT_BACKREF_KEY) {
2248 			subvol_info->parent_id = key.offset;
2249 
2250 			rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2251 			subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref);
2252 
2253 			item_off = btrfs_item_ptr_offset(leaf, slot)
2254 					+ sizeof(struct btrfs_root_ref);
2255 			item_len = btrfs_item_size(leaf, slot)
2256 					- sizeof(struct btrfs_root_ref);
2257 			read_extent_buffer(leaf, subvol_info->name,
2258 					   item_off, item_len);
2259 		} else {
2260 			ret = -ENOENT;
2261 			goto out;
2262 		}
2263 	}
2264 
2265 	btrfs_free_path(path);
2266 	path = NULL;
2267 	if (copy_to_user(argp, subvol_info, sizeof(*subvol_info)))
2268 		ret = -EFAULT;
2269 
2270 out:
2271 	btrfs_put_root(root);
2272 out_free:
2273 	btrfs_free_path(path);
2274 	kfree(subvol_info);
2275 	return ret;
2276 }
2277 
2278 /*
2279  * Return ROOT_REF information of the subvolume containing this inode
2280  * except the subvolume name.
2281  */
2282 static int btrfs_ioctl_get_subvol_rootref(struct btrfs_root *root,
2283 					  void __user *argp)
2284 {
2285 	struct btrfs_ioctl_get_subvol_rootref_args *rootrefs;
2286 	struct btrfs_root_ref *rref;
2287 	struct btrfs_path *path;
2288 	struct btrfs_key key;
2289 	struct extent_buffer *leaf;
2290 	u64 objectid;
2291 	int slot;
2292 	int ret;
2293 	u8 found;
2294 
2295 	path = btrfs_alloc_path();
2296 	if (!path)
2297 		return -ENOMEM;
2298 
2299 	rootrefs = memdup_user(argp, sizeof(*rootrefs));
2300 	if (IS_ERR(rootrefs)) {
2301 		btrfs_free_path(path);
2302 		return PTR_ERR(rootrefs);
2303 	}
2304 
2305 	objectid = btrfs_root_id(root);
2306 	key.objectid = objectid;
2307 	key.type = BTRFS_ROOT_REF_KEY;
2308 	key.offset = rootrefs->min_treeid;
2309 	found = 0;
2310 
2311 	root = root->fs_info->tree_root;
2312 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2313 	if (ret < 0) {
2314 		goto out;
2315 	} else if (path->slots[0] >=
2316 		   btrfs_header_nritems(path->nodes[0])) {
2317 		ret = btrfs_next_leaf(root, path);
2318 		if (ret < 0) {
2319 			goto out;
2320 		} else if (ret > 0) {
2321 			ret = -EUCLEAN;
2322 			goto out;
2323 		}
2324 	}
2325 	while (1) {
2326 		leaf = path->nodes[0];
2327 		slot = path->slots[0];
2328 
2329 		btrfs_item_key_to_cpu(leaf, &key, slot);
2330 		if (key.objectid != objectid || key.type != BTRFS_ROOT_REF_KEY) {
2331 			ret = 0;
2332 			goto out;
2333 		}
2334 
2335 		if (found == BTRFS_MAX_ROOTREF_BUFFER_NUM) {
2336 			ret = -EOVERFLOW;
2337 			goto out;
2338 		}
2339 
2340 		rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2341 		rootrefs->rootref[found].treeid = key.offset;
2342 		rootrefs->rootref[found].dirid =
2343 				  btrfs_root_ref_dirid(leaf, rref);
2344 		found++;
2345 
2346 		ret = btrfs_next_item(root, path);
2347 		if (ret < 0) {
2348 			goto out;
2349 		} else if (ret > 0) {
2350 			ret = -EUCLEAN;
2351 			goto out;
2352 		}
2353 	}
2354 
2355 out:
2356 	btrfs_free_path(path);
2357 
2358 	if (!ret || ret == -EOVERFLOW) {
2359 		rootrefs->num_items = found;
2360 		/* update min_treeid for next search */
2361 		if (found)
2362 			rootrefs->min_treeid =
2363 				rootrefs->rootref[found - 1].treeid + 1;
2364 		if (copy_to_user(argp, rootrefs, sizeof(*rootrefs)))
2365 			ret = -EFAULT;
2366 	}
2367 
2368 	kfree(rootrefs);
2369 
2370 	return ret;
2371 }
2372 
2373 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2374 					     void __user *arg,
2375 					     bool destroy_v2)
2376 {
2377 	struct dentry *parent = file->f_path.dentry;
2378 	struct dentry *dentry;
2379 	struct inode *dir = d_inode(parent);
2380 	struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
2381 	struct inode *inode;
2382 	struct btrfs_root *root = BTRFS_I(dir)->root;
2383 	struct btrfs_root *dest = NULL;
2384 	struct btrfs_ioctl_vol_args *vol_args = NULL;
2385 	struct btrfs_ioctl_vol_args_v2 *vol_args2 = NULL;
2386 	struct mnt_idmap *idmap = file_mnt_idmap(file);
2387 	char *subvol_name, *subvol_name_ptr = NULL;
2388 	int subvol_namelen;
2389 	int ret = 0;
2390 	bool destroy_parent = false;
2391 
2392 	/* We don't support snapshots with extent tree v2 yet. */
2393 	if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2394 		btrfs_err(fs_info,
2395 			  "extent tree v2 doesn't support snapshot deletion yet");
2396 		return -EOPNOTSUPP;
2397 	}
2398 
2399 	if (destroy_v2) {
2400 		vol_args2 = memdup_user(arg, sizeof(*vol_args2));
2401 		if (IS_ERR(vol_args2))
2402 			return PTR_ERR(vol_args2);
2403 
2404 		if (vol_args2->flags & ~BTRFS_SUBVOL_DELETE_ARGS_MASK) {
2405 			ret = -EOPNOTSUPP;
2406 			goto out;
2407 		}
2408 
2409 		/*
2410 		 * If SPEC_BY_ID is not set, we are looking for the subvolume by
2411 		 * name, same as v1 currently does.
2412 		 */
2413 		if (!(vol_args2->flags & BTRFS_SUBVOL_SPEC_BY_ID)) {
2414 			ret = btrfs_check_ioctl_vol_args2_subvol_name(vol_args2);
2415 			if (ret < 0)
2416 				goto out;
2417 			subvol_name = vol_args2->name;
2418 
2419 			ret = mnt_want_write_file(file);
2420 			if (ret)
2421 				goto out;
2422 		} else {
2423 			struct inode *old_dir;
2424 
2425 			if (vol_args2->subvolid < BTRFS_FIRST_FREE_OBJECTID) {
2426 				ret = -EINVAL;
2427 				goto out;
2428 			}
2429 
2430 			ret = mnt_want_write_file(file);
2431 			if (ret)
2432 				goto out;
2433 
2434 			dentry = btrfs_get_dentry(fs_info->sb,
2435 					BTRFS_FIRST_FREE_OBJECTID,
2436 					vol_args2->subvolid, 0);
2437 			if (IS_ERR(dentry)) {
2438 				ret = PTR_ERR(dentry);
2439 				goto out_drop_write;
2440 			}
2441 
2442 			/*
2443 			 * Change the default parent since the subvolume being
2444 			 * deleted can be outside of the current mount point.
2445 			 */
2446 			parent = btrfs_get_parent(dentry);
2447 
2448 			/*
2449 			 * At this point dentry->d_name can point to '/' if the
2450 			 * subvolume we want to destroy is outsite of the
2451 			 * current mount point, so we need to release the
2452 			 * current dentry and execute the lookup to return a new
2453 			 * one with ->d_name pointing to the
2454 			 * <mount point>/subvol_name.
2455 			 */
2456 			dput(dentry);
2457 			if (IS_ERR(parent)) {
2458 				ret = PTR_ERR(parent);
2459 				goto out_drop_write;
2460 			}
2461 			old_dir = dir;
2462 			dir = d_inode(parent);
2463 
2464 			/*
2465 			 * If v2 was used with SPEC_BY_ID, a new parent was
2466 			 * allocated since the subvolume can be outside of the
2467 			 * current mount point. Later on we need to release this
2468 			 * new parent dentry.
2469 			 */
2470 			destroy_parent = true;
2471 
2472 			/*
2473 			 * On idmapped mounts, deletion via subvolid is
2474 			 * restricted to subvolumes that are immediate
2475 			 * ancestors of the inode referenced by the file
2476 			 * descriptor in the ioctl. Otherwise the idmapping
2477 			 * could potentially be abused to delete subvolumes
2478 			 * anywhere in the filesystem the user wouldn't be able
2479 			 * to delete without an idmapped mount.
2480 			 */
2481 			if (old_dir != dir && idmap != &nop_mnt_idmap) {
2482 				ret = -EOPNOTSUPP;
2483 				goto free_parent;
2484 			}
2485 
2486 			subvol_name_ptr = btrfs_get_subvol_name_from_objectid(
2487 						fs_info, vol_args2->subvolid);
2488 			if (IS_ERR(subvol_name_ptr)) {
2489 				ret = PTR_ERR(subvol_name_ptr);
2490 				goto free_parent;
2491 			}
2492 			/* subvol_name_ptr is already nul terminated */
2493 			subvol_name = (char *)kbasename(subvol_name_ptr);
2494 		}
2495 	} else {
2496 		vol_args = memdup_user(arg, sizeof(*vol_args));
2497 		if (IS_ERR(vol_args))
2498 			return PTR_ERR(vol_args);
2499 
2500 		ret = btrfs_check_ioctl_vol_args_path(vol_args);
2501 		if (ret < 0)
2502 			goto out;
2503 
2504 		subvol_name = vol_args->name;
2505 
2506 		ret = mnt_want_write_file(file);
2507 		if (ret)
2508 			goto out;
2509 	}
2510 
2511 	subvol_namelen = strlen(subvol_name);
2512 
2513 	if (strchr(subvol_name, '/') ||
2514 	    strncmp(subvol_name, "..", subvol_namelen) == 0) {
2515 		ret = -EINVAL;
2516 		goto free_subvol_name;
2517 	}
2518 
2519 	if (!S_ISDIR(dir->i_mode)) {
2520 		ret = -ENOTDIR;
2521 		goto free_subvol_name;
2522 	}
2523 
2524 	ret = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
2525 	if (ret == -EINTR)
2526 		goto free_subvol_name;
2527 	dentry = lookup_one(idmap, subvol_name, parent, subvol_namelen);
2528 	if (IS_ERR(dentry)) {
2529 		ret = PTR_ERR(dentry);
2530 		goto out_unlock_dir;
2531 	}
2532 
2533 	if (d_really_is_negative(dentry)) {
2534 		ret = -ENOENT;
2535 		goto out_dput;
2536 	}
2537 
2538 	inode = d_inode(dentry);
2539 	dest = BTRFS_I(inode)->root;
2540 	if (!capable(CAP_SYS_ADMIN)) {
2541 		/*
2542 		 * Regular user.  Only allow this with a special mount
2543 		 * option, when the user has write+exec access to the
2544 		 * subvol root, and when rmdir(2) would have been
2545 		 * allowed.
2546 		 *
2547 		 * Note that this is _not_ check that the subvol is
2548 		 * empty or doesn't contain data that we wouldn't
2549 		 * otherwise be able to delete.
2550 		 *
2551 		 * Users who want to delete empty subvols should try
2552 		 * rmdir(2).
2553 		 */
2554 		ret = -EPERM;
2555 		if (!btrfs_test_opt(fs_info, USER_SUBVOL_RM_ALLOWED))
2556 			goto out_dput;
2557 
2558 		/*
2559 		 * Do not allow deletion if the parent dir is the same
2560 		 * as the dir to be deleted.  That means the ioctl
2561 		 * must be called on the dentry referencing the root
2562 		 * of the subvol, not a random directory contained
2563 		 * within it.
2564 		 */
2565 		ret = -EINVAL;
2566 		if (root == dest)
2567 			goto out_dput;
2568 
2569 		ret = inode_permission(idmap, inode, MAY_WRITE | MAY_EXEC);
2570 		if (ret)
2571 			goto out_dput;
2572 	}
2573 
2574 	/* check if subvolume may be deleted by a user */
2575 	ret = btrfs_may_delete(idmap, dir, dentry, 1);
2576 	if (ret)
2577 		goto out_dput;
2578 
2579 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2580 		ret = -EINVAL;
2581 		goto out_dput;
2582 	}
2583 
2584 	btrfs_inode_lock(BTRFS_I(inode), 0);
2585 	ret = btrfs_delete_subvolume(BTRFS_I(dir), dentry);
2586 	btrfs_inode_unlock(BTRFS_I(inode), 0);
2587 	if (!ret)
2588 		d_delete_notify(dir, dentry);
2589 
2590 out_dput:
2591 	dput(dentry);
2592 out_unlock_dir:
2593 	btrfs_inode_unlock(BTRFS_I(dir), 0);
2594 free_subvol_name:
2595 	kfree(subvol_name_ptr);
2596 free_parent:
2597 	if (destroy_parent)
2598 		dput(parent);
2599 out_drop_write:
2600 	mnt_drop_write_file(file);
2601 out:
2602 	kfree(vol_args2);
2603 	kfree(vol_args);
2604 	return ret;
2605 }
2606 
2607 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2608 {
2609 	struct inode *inode = file_inode(file);
2610 	struct btrfs_root *root = BTRFS_I(inode)->root;
2611 	struct btrfs_ioctl_defrag_range_args range = {0};
2612 	int ret;
2613 
2614 	ret = mnt_want_write_file(file);
2615 	if (ret)
2616 		return ret;
2617 
2618 	if (btrfs_root_readonly(root)) {
2619 		ret = -EROFS;
2620 		goto out;
2621 	}
2622 
2623 	switch (inode->i_mode & S_IFMT) {
2624 	case S_IFDIR:
2625 		if (!capable(CAP_SYS_ADMIN)) {
2626 			ret = -EPERM;
2627 			goto out;
2628 		}
2629 		ret = btrfs_defrag_root(root);
2630 		break;
2631 	case S_IFREG:
2632 		/*
2633 		 * Note that this does not check the file descriptor for write
2634 		 * access. This prevents defragmenting executables that are
2635 		 * running and allows defrag on files open in read-only mode.
2636 		 */
2637 		if (!capable(CAP_SYS_ADMIN) &&
2638 		    inode_permission(&nop_mnt_idmap, inode, MAY_WRITE)) {
2639 			ret = -EPERM;
2640 			goto out;
2641 		}
2642 
2643 		if (argp) {
2644 			if (copy_from_user(&range, argp, sizeof(range))) {
2645 				ret = -EFAULT;
2646 				goto out;
2647 			}
2648 			if (range.flags & ~BTRFS_DEFRAG_RANGE_FLAGS_SUPP) {
2649 				ret = -EOPNOTSUPP;
2650 				goto out;
2651 			}
2652 			/* compression requires us to start the IO */
2653 			if ((range.flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2654 				range.flags |= BTRFS_DEFRAG_RANGE_START_IO;
2655 				range.extent_thresh = (u32)-1;
2656 			}
2657 		} else {
2658 			/* the rest are all set to zero by kzalloc */
2659 			range.len = (u64)-1;
2660 		}
2661 		ret = btrfs_defrag_file(file_inode(file), &file->f_ra,
2662 					&range, BTRFS_OLDEST_GENERATION, 0);
2663 		if (ret > 0)
2664 			ret = 0;
2665 		break;
2666 	default:
2667 		ret = -EINVAL;
2668 	}
2669 out:
2670 	mnt_drop_write_file(file);
2671 	return ret;
2672 }
2673 
2674 static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
2675 {
2676 	struct btrfs_ioctl_vol_args *vol_args;
2677 	bool restore_op = false;
2678 	int ret;
2679 
2680 	if (!capable(CAP_SYS_ADMIN))
2681 		return -EPERM;
2682 
2683 	if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2684 		btrfs_err(fs_info, "device add not supported on extent tree v2 yet");
2685 		return -EINVAL;
2686 	}
2687 
2688 	if (fs_info->fs_devices->temp_fsid) {
2689 		btrfs_err(fs_info,
2690 			  "device add not supported on cloned temp-fsid mount");
2691 		return -EINVAL;
2692 	}
2693 
2694 	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_ADD)) {
2695 		if (!btrfs_exclop_start_try_lock(fs_info, BTRFS_EXCLOP_DEV_ADD))
2696 			return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2697 
2698 		/*
2699 		 * We can do the device add because we have a paused balanced,
2700 		 * change the exclusive op type and remember we should bring
2701 		 * back the paused balance
2702 		 */
2703 		fs_info->exclusive_operation = BTRFS_EXCLOP_DEV_ADD;
2704 		btrfs_exclop_start_unlock(fs_info);
2705 		restore_op = true;
2706 	}
2707 
2708 	vol_args = memdup_user(arg, sizeof(*vol_args));
2709 	if (IS_ERR(vol_args)) {
2710 		ret = PTR_ERR(vol_args);
2711 		goto out;
2712 	}
2713 
2714 	ret = btrfs_check_ioctl_vol_args_path(vol_args);
2715 	if (ret < 0)
2716 		goto out_free;
2717 
2718 	ret = btrfs_init_new_device(fs_info, vol_args->name);
2719 
2720 	if (!ret)
2721 		btrfs_info(fs_info, "disk added %s", vol_args->name);
2722 
2723 out_free:
2724 	kfree(vol_args);
2725 out:
2726 	if (restore_op)
2727 		btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);
2728 	else
2729 		btrfs_exclop_finish(fs_info);
2730 	return ret;
2731 }
2732 
2733 static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
2734 {
2735 	BTRFS_DEV_LOOKUP_ARGS(args);
2736 	struct inode *inode = file_inode(file);
2737 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2738 	struct btrfs_ioctl_vol_args_v2 *vol_args;
2739 	struct file *bdev_file = NULL;
2740 	int ret;
2741 	bool cancel = false;
2742 
2743 	if (!capable(CAP_SYS_ADMIN))
2744 		return -EPERM;
2745 
2746 	vol_args = memdup_user(arg, sizeof(*vol_args));
2747 	if (IS_ERR(vol_args))
2748 		return PTR_ERR(vol_args);
2749 
2750 	if (vol_args->flags & ~BTRFS_DEVICE_REMOVE_ARGS_MASK) {
2751 		ret = -EOPNOTSUPP;
2752 		goto out;
2753 	}
2754 
2755 	ret = btrfs_check_ioctl_vol_args2_subvol_name(vol_args);
2756 	if (ret < 0)
2757 		goto out;
2758 
2759 	if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
2760 		args.devid = vol_args->devid;
2761 	} else if (!strcmp("cancel", vol_args->name)) {
2762 		cancel = true;
2763 	} else {
2764 		ret = btrfs_get_dev_args_from_path(fs_info, &args, vol_args->name);
2765 		if (ret)
2766 			goto out;
2767 	}
2768 
2769 	ret = mnt_want_write_file(file);
2770 	if (ret)
2771 		goto out;
2772 
2773 	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
2774 					   cancel);
2775 	if (ret)
2776 		goto err_drop;
2777 
2778 	/* Exclusive operation is now claimed */
2779 	ret = btrfs_rm_device(fs_info, &args, &bdev_file);
2780 
2781 	btrfs_exclop_finish(fs_info);
2782 
2783 	if (!ret) {
2784 		if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
2785 			btrfs_info(fs_info, "device deleted: id %llu",
2786 					vol_args->devid);
2787 		else
2788 			btrfs_info(fs_info, "device deleted: %s",
2789 					vol_args->name);
2790 	}
2791 err_drop:
2792 	mnt_drop_write_file(file);
2793 	if (bdev_file)
2794 		fput(bdev_file);
2795 out:
2796 	btrfs_put_dev_args_from_path(&args);
2797 	kfree(vol_args);
2798 	return ret;
2799 }
2800 
2801 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
2802 {
2803 	BTRFS_DEV_LOOKUP_ARGS(args);
2804 	struct inode *inode = file_inode(file);
2805 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2806 	struct btrfs_ioctl_vol_args *vol_args;
2807 	struct file *bdev_file = NULL;
2808 	int ret;
2809 	bool cancel = false;
2810 
2811 	if (!capable(CAP_SYS_ADMIN))
2812 		return -EPERM;
2813 
2814 	vol_args = memdup_user(arg, sizeof(*vol_args));
2815 	if (IS_ERR(vol_args))
2816 		return PTR_ERR(vol_args);
2817 
2818 	ret = btrfs_check_ioctl_vol_args_path(vol_args);
2819 	if (ret < 0)
2820 		goto out_free;
2821 
2822 	if (!strcmp("cancel", vol_args->name)) {
2823 		cancel = true;
2824 	} else {
2825 		ret = btrfs_get_dev_args_from_path(fs_info, &args, vol_args->name);
2826 		if (ret)
2827 			goto out;
2828 	}
2829 
2830 	ret = mnt_want_write_file(file);
2831 	if (ret)
2832 		goto out;
2833 
2834 	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
2835 					   cancel);
2836 	if (ret == 0) {
2837 		ret = btrfs_rm_device(fs_info, &args, &bdev_file);
2838 		if (!ret)
2839 			btrfs_info(fs_info, "disk deleted %s", vol_args->name);
2840 		btrfs_exclop_finish(fs_info);
2841 	}
2842 
2843 	mnt_drop_write_file(file);
2844 	if (bdev_file)
2845 		fput(bdev_file);
2846 out:
2847 	btrfs_put_dev_args_from_path(&args);
2848 out_free:
2849 	kfree(vol_args);
2850 	return ret;
2851 }
2852 
2853 static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info,
2854 				void __user *arg)
2855 {
2856 	struct btrfs_ioctl_fs_info_args *fi_args;
2857 	struct btrfs_device *device;
2858 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2859 	u64 flags_in;
2860 	int ret = 0;
2861 
2862 	fi_args = memdup_user(arg, sizeof(*fi_args));
2863 	if (IS_ERR(fi_args))
2864 		return PTR_ERR(fi_args);
2865 
2866 	flags_in = fi_args->flags;
2867 	memset(fi_args, 0, sizeof(*fi_args));
2868 
2869 	rcu_read_lock();
2870 	fi_args->num_devices = fs_devices->num_devices;
2871 
2872 	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
2873 		if (device->devid > fi_args->max_id)
2874 			fi_args->max_id = device->devid;
2875 	}
2876 	rcu_read_unlock();
2877 
2878 	memcpy(&fi_args->fsid, fs_devices->fsid, sizeof(fi_args->fsid));
2879 	fi_args->nodesize = fs_info->nodesize;
2880 	fi_args->sectorsize = fs_info->sectorsize;
2881 	fi_args->clone_alignment = fs_info->sectorsize;
2882 
2883 	if (flags_in & BTRFS_FS_INFO_FLAG_CSUM_INFO) {
2884 		fi_args->csum_type = btrfs_super_csum_type(fs_info->super_copy);
2885 		fi_args->csum_size = btrfs_super_csum_size(fs_info->super_copy);
2886 		fi_args->flags |= BTRFS_FS_INFO_FLAG_CSUM_INFO;
2887 	}
2888 
2889 	if (flags_in & BTRFS_FS_INFO_FLAG_GENERATION) {
2890 		fi_args->generation = btrfs_get_fs_generation(fs_info);
2891 		fi_args->flags |= BTRFS_FS_INFO_FLAG_GENERATION;
2892 	}
2893 
2894 	if (flags_in & BTRFS_FS_INFO_FLAG_METADATA_UUID) {
2895 		memcpy(&fi_args->metadata_uuid, fs_devices->metadata_uuid,
2896 		       sizeof(fi_args->metadata_uuid));
2897 		fi_args->flags |= BTRFS_FS_INFO_FLAG_METADATA_UUID;
2898 	}
2899 
2900 	if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
2901 		ret = -EFAULT;
2902 
2903 	kfree(fi_args);
2904 	return ret;
2905 }
2906 
2907 static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
2908 				 void __user *arg)
2909 {
2910 	BTRFS_DEV_LOOKUP_ARGS(args);
2911 	struct btrfs_ioctl_dev_info_args *di_args;
2912 	struct btrfs_device *dev;
2913 	int ret = 0;
2914 
2915 	di_args = memdup_user(arg, sizeof(*di_args));
2916 	if (IS_ERR(di_args))
2917 		return PTR_ERR(di_args);
2918 
2919 	args.devid = di_args->devid;
2920 	if (!btrfs_is_empty_uuid(di_args->uuid))
2921 		args.uuid = di_args->uuid;
2922 
2923 	rcu_read_lock();
2924 	dev = btrfs_find_device(fs_info->fs_devices, &args);
2925 	if (!dev) {
2926 		ret = -ENODEV;
2927 		goto out;
2928 	}
2929 
2930 	di_args->devid = dev->devid;
2931 	di_args->bytes_used = btrfs_device_get_bytes_used(dev);
2932 	di_args->total_bytes = btrfs_device_get_total_bytes(dev);
2933 	memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2934 	memcpy(di_args->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2935 	if (dev->name)
2936 		strscpy(di_args->path, btrfs_dev_name(dev), sizeof(di_args->path));
2937 	else
2938 		di_args->path[0] = '\0';
2939 
2940 out:
2941 	rcu_read_unlock();
2942 	if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2943 		ret = -EFAULT;
2944 
2945 	kfree(di_args);
2946 	return ret;
2947 }
2948 
2949 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
2950 {
2951 	struct inode *inode = file_inode(file);
2952 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2953 	struct btrfs_root *root = BTRFS_I(inode)->root;
2954 	struct btrfs_root *new_root;
2955 	struct btrfs_dir_item *di;
2956 	struct btrfs_trans_handle *trans;
2957 	struct btrfs_path *path = NULL;
2958 	struct btrfs_disk_key disk_key;
2959 	struct fscrypt_str name = FSTR_INIT("default", 7);
2960 	u64 objectid = 0;
2961 	u64 dir_id;
2962 	int ret;
2963 
2964 	if (!capable(CAP_SYS_ADMIN))
2965 		return -EPERM;
2966 
2967 	ret = mnt_want_write_file(file);
2968 	if (ret)
2969 		return ret;
2970 
2971 	if (copy_from_user(&objectid, argp, sizeof(objectid))) {
2972 		ret = -EFAULT;
2973 		goto out;
2974 	}
2975 
2976 	if (!objectid)
2977 		objectid = BTRFS_FS_TREE_OBJECTID;
2978 
2979 	new_root = btrfs_get_fs_root(fs_info, objectid, true);
2980 	if (IS_ERR(new_root)) {
2981 		ret = PTR_ERR(new_root);
2982 		goto out;
2983 	}
2984 	if (!is_fstree(btrfs_root_id(new_root))) {
2985 		ret = -ENOENT;
2986 		goto out_free;
2987 	}
2988 
2989 	path = btrfs_alloc_path();
2990 	if (!path) {
2991 		ret = -ENOMEM;
2992 		goto out_free;
2993 	}
2994 
2995 	trans = btrfs_start_transaction(root, 1);
2996 	if (IS_ERR(trans)) {
2997 		ret = PTR_ERR(trans);
2998 		goto out_free;
2999 	}
3000 
3001 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
3002 	di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
3003 				   dir_id, &name, 1);
3004 	if (IS_ERR_OR_NULL(di)) {
3005 		btrfs_release_path(path);
3006 		btrfs_end_transaction(trans);
3007 		btrfs_err(fs_info,
3008 			  "Umm, you don't have the default diritem, this isn't going to work");
3009 		ret = -ENOENT;
3010 		goto out_free;
3011 	}
3012 
3013 	btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
3014 	btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
3015 	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
3016 	btrfs_release_path(path);
3017 
3018 	btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
3019 	btrfs_end_transaction(trans);
3020 out_free:
3021 	btrfs_put_root(new_root);
3022 	btrfs_free_path(path);
3023 out:
3024 	mnt_drop_write_file(file);
3025 	return ret;
3026 }
3027 
3028 static void get_block_group_info(struct list_head *groups_list,
3029 				 struct btrfs_ioctl_space_info *space)
3030 {
3031 	struct btrfs_block_group *block_group;
3032 
3033 	space->total_bytes = 0;
3034 	space->used_bytes = 0;
3035 	space->flags = 0;
3036 	list_for_each_entry(block_group, groups_list, list) {
3037 		space->flags = block_group->flags;
3038 		space->total_bytes += block_group->length;
3039 		space->used_bytes += block_group->used;
3040 	}
3041 }
3042 
3043 static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info,
3044 				   void __user *arg)
3045 {
3046 	struct btrfs_ioctl_space_args space_args = { 0 };
3047 	struct btrfs_ioctl_space_info space;
3048 	struct btrfs_ioctl_space_info *dest;
3049 	struct btrfs_ioctl_space_info *dest_orig;
3050 	struct btrfs_ioctl_space_info __user *user_dest;
3051 	struct btrfs_space_info *info;
3052 	static const u64 types[] = {
3053 		BTRFS_BLOCK_GROUP_DATA,
3054 		BTRFS_BLOCK_GROUP_SYSTEM,
3055 		BTRFS_BLOCK_GROUP_METADATA,
3056 		BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA
3057 	};
3058 	int num_types = 4;
3059 	int alloc_size;
3060 	int ret = 0;
3061 	u64 slot_count = 0;
3062 	int i, c;
3063 
3064 	if (copy_from_user(&space_args,
3065 			   (struct btrfs_ioctl_space_args __user *)arg,
3066 			   sizeof(space_args)))
3067 		return -EFAULT;
3068 
3069 	for (i = 0; i < num_types; i++) {
3070 		struct btrfs_space_info *tmp;
3071 
3072 		info = NULL;
3073 		list_for_each_entry(tmp, &fs_info->space_info, list) {
3074 			if (tmp->flags == types[i]) {
3075 				info = tmp;
3076 				break;
3077 			}
3078 		}
3079 
3080 		if (!info)
3081 			continue;
3082 
3083 		down_read(&info->groups_sem);
3084 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3085 			if (!list_empty(&info->block_groups[c]))
3086 				slot_count++;
3087 		}
3088 		up_read(&info->groups_sem);
3089 	}
3090 
3091 	/*
3092 	 * Global block reserve, exported as a space_info
3093 	 */
3094 	slot_count++;
3095 
3096 	/* space_slots == 0 means they are asking for a count */
3097 	if (space_args.space_slots == 0) {
3098 		space_args.total_spaces = slot_count;
3099 		goto out;
3100 	}
3101 
3102 	slot_count = min_t(u64, space_args.space_slots, slot_count);
3103 
3104 	alloc_size = sizeof(*dest) * slot_count;
3105 
3106 	/* we generally have at most 6 or so space infos, one for each raid
3107 	 * level.  So, a whole page should be more than enough for everyone
3108 	 */
3109 	if (alloc_size > PAGE_SIZE)
3110 		return -ENOMEM;
3111 
3112 	space_args.total_spaces = 0;
3113 	dest = kmalloc(alloc_size, GFP_KERNEL);
3114 	if (!dest)
3115 		return -ENOMEM;
3116 	dest_orig = dest;
3117 
3118 	/* now we have a buffer to copy into */
3119 	for (i = 0; i < num_types; i++) {
3120 		struct btrfs_space_info *tmp;
3121 
3122 		if (!slot_count)
3123 			break;
3124 
3125 		info = NULL;
3126 		list_for_each_entry(tmp, &fs_info->space_info, list) {
3127 			if (tmp->flags == types[i]) {
3128 				info = tmp;
3129 				break;
3130 			}
3131 		}
3132 
3133 		if (!info)
3134 			continue;
3135 		down_read(&info->groups_sem);
3136 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3137 			if (!list_empty(&info->block_groups[c])) {
3138 				get_block_group_info(&info->block_groups[c],
3139 						     &space);
3140 				memcpy(dest, &space, sizeof(space));
3141 				dest++;
3142 				space_args.total_spaces++;
3143 				slot_count--;
3144 			}
3145 			if (!slot_count)
3146 				break;
3147 		}
3148 		up_read(&info->groups_sem);
3149 	}
3150 
3151 	/*
3152 	 * Add global block reserve
3153 	 */
3154 	if (slot_count) {
3155 		struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3156 
3157 		spin_lock(&block_rsv->lock);
3158 		space.total_bytes = block_rsv->size;
3159 		space.used_bytes = block_rsv->size - block_rsv->reserved;
3160 		spin_unlock(&block_rsv->lock);
3161 		space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
3162 		memcpy(dest, &space, sizeof(space));
3163 		space_args.total_spaces++;
3164 	}
3165 
3166 	user_dest = (struct btrfs_ioctl_space_info __user *)
3167 		(arg + sizeof(struct btrfs_ioctl_space_args));
3168 
3169 	if (copy_to_user(user_dest, dest_orig, alloc_size))
3170 		ret = -EFAULT;
3171 
3172 	kfree(dest_orig);
3173 out:
3174 	if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
3175 		ret = -EFAULT;
3176 
3177 	return ret;
3178 }
3179 
3180 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
3181 					    void __user *argp)
3182 {
3183 	struct btrfs_trans_handle *trans;
3184 	u64 transid;
3185 
3186 	/*
3187 	 * Start orphan cleanup here for the given root in case it hasn't been
3188 	 * started already by other means. Errors are handled in the other
3189 	 * functions during transaction commit.
3190 	 */
3191 	btrfs_orphan_cleanup(root);
3192 
3193 	trans = btrfs_attach_transaction_barrier(root);
3194 	if (IS_ERR(trans)) {
3195 		if (PTR_ERR(trans) != -ENOENT)
3196 			return PTR_ERR(trans);
3197 
3198 		/* No running transaction, don't bother */
3199 		transid = btrfs_get_last_trans_committed(root->fs_info);
3200 		goto out;
3201 	}
3202 	transid = trans->transid;
3203 	btrfs_commit_transaction_async(trans);
3204 out:
3205 	if (argp)
3206 		if (copy_to_user(argp, &transid, sizeof(transid)))
3207 			return -EFAULT;
3208 	return 0;
3209 }
3210 
3211 static noinline long btrfs_ioctl_wait_sync(struct btrfs_fs_info *fs_info,
3212 					   void __user *argp)
3213 {
3214 	/* By default wait for the current transaction. */
3215 	u64 transid = 0;
3216 
3217 	if (argp)
3218 		if (copy_from_user(&transid, argp, sizeof(transid)))
3219 			return -EFAULT;
3220 
3221 	return btrfs_wait_for_commit(fs_info, transid);
3222 }
3223 
3224 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
3225 {
3226 	struct btrfs_fs_info *fs_info = inode_to_fs_info(file_inode(file));
3227 	struct btrfs_ioctl_scrub_args *sa;
3228 	int ret;
3229 
3230 	if (!capable(CAP_SYS_ADMIN))
3231 		return -EPERM;
3232 
3233 	if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
3234 		btrfs_err(fs_info, "scrub is not supported on extent tree v2 yet");
3235 		return -EINVAL;
3236 	}
3237 
3238 	sa = memdup_user(arg, sizeof(*sa));
3239 	if (IS_ERR(sa))
3240 		return PTR_ERR(sa);
3241 
3242 	if (sa->flags & ~BTRFS_SCRUB_SUPPORTED_FLAGS) {
3243 		ret = -EOPNOTSUPP;
3244 		goto out;
3245 	}
3246 
3247 	if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
3248 		ret = mnt_want_write_file(file);
3249 		if (ret)
3250 			goto out;
3251 	}
3252 
3253 	ret = btrfs_scrub_dev(fs_info, sa->devid, sa->start, sa->end,
3254 			      &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
3255 			      0);
3256 
3257 	/*
3258 	 * Copy scrub args to user space even if btrfs_scrub_dev() returned an
3259 	 * error. This is important as it allows user space to know how much
3260 	 * progress scrub has done. For example, if scrub is canceled we get
3261 	 * -ECANCELED from btrfs_scrub_dev() and return that error back to user
3262 	 * space. Later user space can inspect the progress from the structure
3263 	 * btrfs_ioctl_scrub_args and resume scrub from where it left off
3264 	 * previously (btrfs-progs does this).
3265 	 * If we fail to copy the btrfs_ioctl_scrub_args structure to user space
3266 	 * then return -EFAULT to signal the structure was not copied or it may
3267 	 * be corrupt and unreliable due to a partial copy.
3268 	 */
3269 	if (copy_to_user(arg, sa, sizeof(*sa)))
3270 		ret = -EFAULT;
3271 
3272 	if (!(sa->flags & BTRFS_SCRUB_READONLY))
3273 		mnt_drop_write_file(file);
3274 out:
3275 	kfree(sa);
3276 	return ret;
3277 }
3278 
3279 static long btrfs_ioctl_scrub_cancel(struct btrfs_fs_info *fs_info)
3280 {
3281 	if (!capable(CAP_SYS_ADMIN))
3282 		return -EPERM;
3283 
3284 	return btrfs_scrub_cancel(fs_info);
3285 }
3286 
3287 static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
3288 				       void __user *arg)
3289 {
3290 	struct btrfs_ioctl_scrub_args *sa;
3291 	int ret;
3292 
3293 	if (!capable(CAP_SYS_ADMIN))
3294 		return -EPERM;
3295 
3296 	sa = memdup_user(arg, sizeof(*sa));
3297 	if (IS_ERR(sa))
3298 		return PTR_ERR(sa);
3299 
3300 	ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
3301 
3302 	if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
3303 		ret = -EFAULT;
3304 
3305 	kfree(sa);
3306 	return ret;
3307 }
3308 
3309 static long btrfs_ioctl_get_dev_stats(struct btrfs_fs_info *fs_info,
3310 				      void __user *arg)
3311 {
3312 	struct btrfs_ioctl_get_dev_stats *sa;
3313 	int ret;
3314 
3315 	sa = memdup_user(arg, sizeof(*sa));
3316 	if (IS_ERR(sa))
3317 		return PTR_ERR(sa);
3318 
3319 	if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
3320 		kfree(sa);
3321 		return -EPERM;
3322 	}
3323 
3324 	ret = btrfs_get_dev_stats(fs_info, sa);
3325 
3326 	if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
3327 		ret = -EFAULT;
3328 
3329 	kfree(sa);
3330 	return ret;
3331 }
3332 
3333 static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
3334 				    void __user *arg)
3335 {
3336 	struct btrfs_ioctl_dev_replace_args *p;
3337 	int ret;
3338 
3339 	if (!capable(CAP_SYS_ADMIN))
3340 		return -EPERM;
3341 
3342 	if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
3343 		btrfs_err(fs_info, "device replace not supported on extent tree v2 yet");
3344 		return -EINVAL;
3345 	}
3346 
3347 	p = memdup_user(arg, sizeof(*p));
3348 	if (IS_ERR(p))
3349 		return PTR_ERR(p);
3350 
3351 	switch (p->cmd) {
3352 	case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
3353 		if (sb_rdonly(fs_info->sb)) {
3354 			ret = -EROFS;
3355 			goto out;
3356 		}
3357 		if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_REPLACE)) {
3358 			ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3359 		} else {
3360 			ret = btrfs_dev_replace_by_ioctl(fs_info, p);
3361 			btrfs_exclop_finish(fs_info);
3362 		}
3363 		break;
3364 	case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
3365 		btrfs_dev_replace_status(fs_info, p);
3366 		ret = 0;
3367 		break;
3368 	case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
3369 		p->result = btrfs_dev_replace_cancel(fs_info);
3370 		ret = 0;
3371 		break;
3372 	default:
3373 		ret = -EINVAL;
3374 		break;
3375 	}
3376 
3377 	if ((ret == 0 || ret == -ECANCELED) && copy_to_user(arg, p, sizeof(*p)))
3378 		ret = -EFAULT;
3379 out:
3380 	kfree(p);
3381 	return ret;
3382 }
3383 
3384 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
3385 {
3386 	int ret = 0;
3387 	int i;
3388 	u64 rel_ptr;
3389 	int size;
3390 	struct btrfs_ioctl_ino_path_args *ipa = NULL;
3391 	struct inode_fs_paths *ipath = NULL;
3392 	struct btrfs_path *path;
3393 
3394 	if (!capable(CAP_DAC_READ_SEARCH))
3395 		return -EPERM;
3396 
3397 	path = btrfs_alloc_path();
3398 	if (!path) {
3399 		ret = -ENOMEM;
3400 		goto out;
3401 	}
3402 
3403 	ipa = memdup_user(arg, sizeof(*ipa));
3404 	if (IS_ERR(ipa)) {
3405 		ret = PTR_ERR(ipa);
3406 		ipa = NULL;
3407 		goto out;
3408 	}
3409 
3410 	size = min_t(u32, ipa->size, 4096);
3411 	ipath = init_ipath(size, root, path);
3412 	if (IS_ERR(ipath)) {
3413 		ret = PTR_ERR(ipath);
3414 		ipath = NULL;
3415 		goto out;
3416 	}
3417 
3418 	ret = paths_from_inode(ipa->inum, ipath);
3419 	if (ret < 0)
3420 		goto out;
3421 
3422 	for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
3423 		rel_ptr = ipath->fspath->val[i] -
3424 			  (u64)(unsigned long)ipath->fspath->val;
3425 		ipath->fspath->val[i] = rel_ptr;
3426 	}
3427 
3428 	btrfs_free_path(path);
3429 	path = NULL;
3430 	ret = copy_to_user((void __user *)(unsigned long)ipa->fspath,
3431 			   ipath->fspath, size);
3432 	if (ret) {
3433 		ret = -EFAULT;
3434 		goto out;
3435 	}
3436 
3437 out:
3438 	btrfs_free_path(path);
3439 	free_ipath(ipath);
3440 	kfree(ipa);
3441 
3442 	return ret;
3443 }
3444 
3445 static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
3446 					void __user *arg, int version)
3447 {
3448 	int ret = 0;
3449 	int size;
3450 	struct btrfs_ioctl_logical_ino_args *loi;
3451 	struct btrfs_data_container *inodes = NULL;
3452 	struct btrfs_path *path = NULL;
3453 	bool ignore_offset;
3454 
3455 	if (!capable(CAP_SYS_ADMIN))
3456 		return -EPERM;
3457 
3458 	loi = memdup_user(arg, sizeof(*loi));
3459 	if (IS_ERR(loi))
3460 		return PTR_ERR(loi);
3461 
3462 	if (version == 1) {
3463 		ignore_offset = false;
3464 		size = min_t(u32, loi->size, SZ_64K);
3465 	} else {
3466 		/* All reserved bits must be 0 for now */
3467 		if (memchr_inv(loi->reserved, 0, sizeof(loi->reserved))) {
3468 			ret = -EINVAL;
3469 			goto out_loi;
3470 		}
3471 		/* Only accept flags we have defined so far */
3472 		if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) {
3473 			ret = -EINVAL;
3474 			goto out_loi;
3475 		}
3476 		ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET;
3477 		size = min_t(u32, loi->size, SZ_16M);
3478 	}
3479 
3480 	inodes = init_data_container(size);
3481 	if (IS_ERR(inodes)) {
3482 		ret = PTR_ERR(inodes);
3483 		goto out_loi;
3484 	}
3485 
3486 	path = btrfs_alloc_path();
3487 	if (!path) {
3488 		ret = -ENOMEM;
3489 		goto out;
3490 	}
3491 	ret = iterate_inodes_from_logical(loi->logical, fs_info, path,
3492 					  inodes, ignore_offset);
3493 	btrfs_free_path(path);
3494 	if (ret == -EINVAL)
3495 		ret = -ENOENT;
3496 	if (ret < 0)
3497 		goto out;
3498 
3499 	ret = copy_to_user((void __user *)(unsigned long)loi->inodes, inodes,
3500 			   size);
3501 	if (ret)
3502 		ret = -EFAULT;
3503 
3504 out:
3505 	kvfree(inodes);
3506 out_loi:
3507 	kfree(loi);
3508 
3509 	return ret;
3510 }
3511 
3512 void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
3513 			       struct btrfs_ioctl_balance_args *bargs)
3514 {
3515 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3516 
3517 	bargs->flags = bctl->flags;
3518 
3519 	if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags))
3520 		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
3521 	if (atomic_read(&fs_info->balance_pause_req))
3522 		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
3523 	if (atomic_read(&fs_info->balance_cancel_req))
3524 		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
3525 
3526 	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
3527 	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
3528 	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
3529 
3530 	spin_lock(&fs_info->balance_lock);
3531 	memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
3532 	spin_unlock(&fs_info->balance_lock);
3533 }
3534 
3535 /*
3536  * Try to acquire fs_info::balance_mutex as well as set BTRFS_EXLCOP_BALANCE as
3537  * required.
3538  *
3539  * @fs_info:       the filesystem
3540  * @excl_acquired: ptr to boolean value which is set to false in case balance
3541  *                 is being resumed
3542  *
3543  * Return 0 on success in which case both fs_info::balance is acquired as well
3544  * as exclusive ops are blocked. In case of failure return an error code.
3545  */
3546 static int btrfs_try_lock_balance(struct btrfs_fs_info *fs_info, bool *excl_acquired)
3547 {
3548 	int ret;
3549 
3550 	/*
3551 	 * Exclusive operation is locked. Three possibilities:
3552 	 *   (1) some other op is running
3553 	 *   (2) balance is running
3554 	 *   (3) balance is paused -- special case (think resume)
3555 	 */
3556 	while (1) {
3557 		if (btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {
3558 			*excl_acquired = true;
3559 			mutex_lock(&fs_info->balance_mutex);
3560 			return 0;
3561 		}
3562 
3563 		mutex_lock(&fs_info->balance_mutex);
3564 		if (fs_info->balance_ctl) {
3565 			/* This is either (2) or (3) */
3566 			if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
3567 				/* This is (2) */
3568 				ret = -EINPROGRESS;
3569 				goto out_failure;
3570 
3571 			} else {
3572 				mutex_unlock(&fs_info->balance_mutex);
3573 				/*
3574 				 * Lock released to allow other waiters to
3575 				 * continue, we'll reexamine the status again.
3576 				 */
3577 				mutex_lock(&fs_info->balance_mutex);
3578 
3579 				if (fs_info->balance_ctl &&
3580 				    !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
3581 					/* This is (3) */
3582 					*excl_acquired = false;
3583 					return 0;
3584 				}
3585 			}
3586 		} else {
3587 			/* This is (1) */
3588 			ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3589 			goto out_failure;
3590 		}
3591 
3592 		mutex_unlock(&fs_info->balance_mutex);
3593 	}
3594 
3595 out_failure:
3596 	mutex_unlock(&fs_info->balance_mutex);
3597 	*excl_acquired = false;
3598 	return ret;
3599 }
3600 
3601 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
3602 {
3603 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
3604 	struct btrfs_fs_info *fs_info = root->fs_info;
3605 	struct btrfs_ioctl_balance_args *bargs;
3606 	struct btrfs_balance_control *bctl;
3607 	bool need_unlock = true;
3608 	int ret;
3609 
3610 	if (!capable(CAP_SYS_ADMIN))
3611 		return -EPERM;
3612 
3613 	ret = mnt_want_write_file(file);
3614 	if (ret)
3615 		return ret;
3616 
3617 	bargs = memdup_user(arg, sizeof(*bargs));
3618 	if (IS_ERR(bargs)) {
3619 		ret = PTR_ERR(bargs);
3620 		bargs = NULL;
3621 		goto out;
3622 	}
3623 
3624 	ret = btrfs_try_lock_balance(fs_info, &need_unlock);
3625 	if (ret)
3626 		goto out;
3627 
3628 	lockdep_assert_held(&fs_info->balance_mutex);
3629 
3630 	if (bargs->flags & BTRFS_BALANCE_RESUME) {
3631 		if (!fs_info->balance_ctl) {
3632 			ret = -ENOTCONN;
3633 			goto out_unlock;
3634 		}
3635 
3636 		bctl = fs_info->balance_ctl;
3637 		spin_lock(&fs_info->balance_lock);
3638 		bctl->flags |= BTRFS_BALANCE_RESUME;
3639 		spin_unlock(&fs_info->balance_lock);
3640 		btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE);
3641 
3642 		goto do_balance;
3643 	}
3644 
3645 	if (bargs->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
3646 		ret = -EINVAL;
3647 		goto out_unlock;
3648 	}
3649 
3650 	if (fs_info->balance_ctl) {
3651 		ret = -EINPROGRESS;
3652 		goto out_unlock;
3653 	}
3654 
3655 	bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
3656 	if (!bctl) {
3657 		ret = -ENOMEM;
3658 		goto out_unlock;
3659 	}
3660 
3661 	memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
3662 	memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
3663 	memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
3664 
3665 	bctl->flags = bargs->flags;
3666 do_balance:
3667 	/*
3668 	 * Ownership of bctl and exclusive operation goes to btrfs_balance.
3669 	 * bctl is freed in reset_balance_state, or, if restriper was paused
3670 	 * all the way until unmount, in free_fs_info.  The flag should be
3671 	 * cleared after reset_balance_state.
3672 	 */
3673 	need_unlock = false;
3674 
3675 	ret = btrfs_balance(fs_info, bctl, bargs);
3676 	bctl = NULL;
3677 
3678 	if (ret == 0 || ret == -ECANCELED) {
3679 		if (copy_to_user(arg, bargs, sizeof(*bargs)))
3680 			ret = -EFAULT;
3681 	}
3682 
3683 	kfree(bctl);
3684 out_unlock:
3685 	mutex_unlock(&fs_info->balance_mutex);
3686 	if (need_unlock)
3687 		btrfs_exclop_finish(fs_info);
3688 out:
3689 	mnt_drop_write_file(file);
3690 	kfree(bargs);
3691 	return ret;
3692 }
3693 
3694 static long btrfs_ioctl_balance_ctl(struct btrfs_fs_info *fs_info, int cmd)
3695 {
3696 	if (!capable(CAP_SYS_ADMIN))
3697 		return -EPERM;
3698 
3699 	switch (cmd) {
3700 	case BTRFS_BALANCE_CTL_PAUSE:
3701 		return btrfs_pause_balance(fs_info);
3702 	case BTRFS_BALANCE_CTL_CANCEL:
3703 		return btrfs_cancel_balance(fs_info);
3704 	}
3705 
3706 	return -EINVAL;
3707 }
3708 
3709 static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
3710 					 void __user *arg)
3711 {
3712 	struct btrfs_ioctl_balance_args *bargs;
3713 	int ret = 0;
3714 
3715 	if (!capable(CAP_SYS_ADMIN))
3716 		return -EPERM;
3717 
3718 	mutex_lock(&fs_info->balance_mutex);
3719 	if (!fs_info->balance_ctl) {
3720 		ret = -ENOTCONN;
3721 		goto out;
3722 	}
3723 
3724 	bargs = kzalloc(sizeof(*bargs), GFP_KERNEL);
3725 	if (!bargs) {
3726 		ret = -ENOMEM;
3727 		goto out;
3728 	}
3729 
3730 	btrfs_update_ioctl_balance_args(fs_info, bargs);
3731 
3732 	if (copy_to_user(arg, bargs, sizeof(*bargs)))
3733 		ret = -EFAULT;
3734 
3735 	kfree(bargs);
3736 out:
3737 	mutex_unlock(&fs_info->balance_mutex);
3738 	return ret;
3739 }
3740 
3741 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
3742 {
3743 	struct inode *inode = file_inode(file);
3744 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
3745 	struct btrfs_ioctl_quota_ctl_args *sa;
3746 	int ret;
3747 
3748 	if (!capable(CAP_SYS_ADMIN))
3749 		return -EPERM;
3750 
3751 	ret = mnt_want_write_file(file);
3752 	if (ret)
3753 		return ret;
3754 
3755 	sa = memdup_user(arg, sizeof(*sa));
3756 	if (IS_ERR(sa)) {
3757 		ret = PTR_ERR(sa);
3758 		goto drop_write;
3759 	}
3760 
3761 	switch (sa->cmd) {
3762 	case BTRFS_QUOTA_CTL_ENABLE:
3763 	case BTRFS_QUOTA_CTL_ENABLE_SIMPLE_QUOTA:
3764 		down_write(&fs_info->subvol_sem);
3765 		ret = btrfs_quota_enable(fs_info, sa);
3766 		up_write(&fs_info->subvol_sem);
3767 		break;
3768 	case BTRFS_QUOTA_CTL_DISABLE:
3769 		/*
3770 		 * Lock the cleaner mutex to prevent races with concurrent
3771 		 * relocation, because relocation may be building backrefs for
3772 		 * blocks of the quota root while we are deleting the root. This
3773 		 * is like dropping fs roots of deleted snapshots/subvolumes, we
3774 		 * need the same protection.
3775 		 *
3776 		 * This also prevents races between concurrent tasks trying to
3777 		 * disable quotas, because we will unlock and relock
3778 		 * qgroup_ioctl_lock across BTRFS_FS_QUOTA_ENABLED changes.
3779 		 *
3780 		 * We take this here because we have the dependency of
3781 		 *
3782 		 * inode_lock -> subvol_sem
3783 		 *
3784 		 * because of rename.  With relocation we can prealloc extents,
3785 		 * so that makes the dependency chain
3786 		 *
3787 		 * cleaner_mutex -> inode_lock -> subvol_sem
3788 		 *
3789 		 * so we must take the cleaner_mutex here before we take the
3790 		 * subvol_sem.  The deadlock can't actually happen, but this
3791 		 * quiets lockdep.
3792 		 */
3793 		mutex_lock(&fs_info->cleaner_mutex);
3794 		down_write(&fs_info->subvol_sem);
3795 		ret = btrfs_quota_disable(fs_info);
3796 		up_write(&fs_info->subvol_sem);
3797 		mutex_unlock(&fs_info->cleaner_mutex);
3798 		break;
3799 	default:
3800 		ret = -EINVAL;
3801 		break;
3802 	}
3803 
3804 	kfree(sa);
3805 drop_write:
3806 	mnt_drop_write_file(file);
3807 	return ret;
3808 }
3809 
3810 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
3811 {
3812 	struct inode *inode = file_inode(file);
3813 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
3814 	struct btrfs_root *root = BTRFS_I(inode)->root;
3815 	struct btrfs_ioctl_qgroup_assign_args *sa;
3816 	struct btrfs_trans_handle *trans;
3817 	int ret;
3818 	int err;
3819 
3820 	if (!capable(CAP_SYS_ADMIN))
3821 		return -EPERM;
3822 
3823 	ret = mnt_want_write_file(file);
3824 	if (ret)
3825 		return ret;
3826 
3827 	sa = memdup_user(arg, sizeof(*sa));
3828 	if (IS_ERR(sa)) {
3829 		ret = PTR_ERR(sa);
3830 		goto drop_write;
3831 	}
3832 
3833 	trans = btrfs_join_transaction(root);
3834 	if (IS_ERR(trans)) {
3835 		ret = PTR_ERR(trans);
3836 		goto out;
3837 	}
3838 
3839 	if (sa->assign) {
3840 		ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst);
3841 	} else {
3842 		ret = btrfs_del_qgroup_relation(trans, sa->src, sa->dst);
3843 	}
3844 
3845 	/* update qgroup status and info */
3846 	mutex_lock(&fs_info->qgroup_ioctl_lock);
3847 	err = btrfs_run_qgroups(trans);
3848 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
3849 	if (err < 0)
3850 		btrfs_handle_fs_error(fs_info, err,
3851 				      "failed to update qgroup status and info");
3852 	err = btrfs_end_transaction(trans);
3853 	if (err && !ret)
3854 		ret = err;
3855 
3856 out:
3857 	kfree(sa);
3858 drop_write:
3859 	mnt_drop_write_file(file);
3860 	return ret;
3861 }
3862 
3863 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
3864 {
3865 	struct inode *inode = file_inode(file);
3866 	struct btrfs_root *root = BTRFS_I(inode)->root;
3867 	struct btrfs_ioctl_qgroup_create_args *sa;
3868 	struct btrfs_trans_handle *trans;
3869 	int ret;
3870 	int err;
3871 
3872 	if (!capable(CAP_SYS_ADMIN))
3873 		return -EPERM;
3874 
3875 	ret = mnt_want_write_file(file);
3876 	if (ret)
3877 		return ret;
3878 
3879 	sa = memdup_user(arg, sizeof(*sa));
3880 	if (IS_ERR(sa)) {
3881 		ret = PTR_ERR(sa);
3882 		goto drop_write;
3883 	}
3884 
3885 	if (!sa->qgroupid) {
3886 		ret = -EINVAL;
3887 		goto out;
3888 	}
3889 
3890 	if (sa->create && is_fstree(sa->qgroupid)) {
3891 		ret = -EINVAL;
3892 		goto out;
3893 	}
3894 
3895 	trans = btrfs_join_transaction(root);
3896 	if (IS_ERR(trans)) {
3897 		ret = PTR_ERR(trans);
3898 		goto out;
3899 	}
3900 
3901 	if (sa->create) {
3902 		ret = btrfs_create_qgroup(trans, sa->qgroupid);
3903 	} else {
3904 		ret = btrfs_remove_qgroup(trans, sa->qgroupid);
3905 	}
3906 
3907 	err = btrfs_end_transaction(trans);
3908 	if (err && !ret)
3909 		ret = err;
3910 
3911 out:
3912 	kfree(sa);
3913 drop_write:
3914 	mnt_drop_write_file(file);
3915 	return ret;
3916 }
3917 
3918 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
3919 {
3920 	struct inode *inode = file_inode(file);
3921 	struct btrfs_root *root = BTRFS_I(inode)->root;
3922 	struct btrfs_ioctl_qgroup_limit_args *sa;
3923 	struct btrfs_trans_handle *trans;
3924 	int ret;
3925 	int err;
3926 	u64 qgroupid;
3927 
3928 	if (!capable(CAP_SYS_ADMIN))
3929 		return -EPERM;
3930 
3931 	ret = mnt_want_write_file(file);
3932 	if (ret)
3933 		return ret;
3934 
3935 	sa = memdup_user(arg, sizeof(*sa));
3936 	if (IS_ERR(sa)) {
3937 		ret = PTR_ERR(sa);
3938 		goto drop_write;
3939 	}
3940 
3941 	trans = btrfs_join_transaction(root);
3942 	if (IS_ERR(trans)) {
3943 		ret = PTR_ERR(trans);
3944 		goto out;
3945 	}
3946 
3947 	qgroupid = sa->qgroupid;
3948 	if (!qgroupid) {
3949 		/* take the current subvol as qgroup */
3950 		qgroupid = btrfs_root_id(root);
3951 	}
3952 
3953 	ret = btrfs_limit_qgroup(trans, qgroupid, &sa->lim);
3954 
3955 	err = btrfs_end_transaction(trans);
3956 	if (err && !ret)
3957 		ret = err;
3958 
3959 out:
3960 	kfree(sa);
3961 drop_write:
3962 	mnt_drop_write_file(file);
3963 	return ret;
3964 }
3965 
3966 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
3967 {
3968 	struct inode *inode = file_inode(file);
3969 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
3970 	struct btrfs_ioctl_quota_rescan_args *qsa;
3971 	int ret;
3972 
3973 	if (!capable(CAP_SYS_ADMIN))
3974 		return -EPERM;
3975 
3976 	ret = mnt_want_write_file(file);
3977 	if (ret)
3978 		return ret;
3979 
3980 	qsa = memdup_user(arg, sizeof(*qsa));
3981 	if (IS_ERR(qsa)) {
3982 		ret = PTR_ERR(qsa);
3983 		goto drop_write;
3984 	}
3985 
3986 	if (qsa->flags) {
3987 		ret = -EINVAL;
3988 		goto out;
3989 	}
3990 
3991 	ret = btrfs_qgroup_rescan(fs_info);
3992 
3993 out:
3994 	kfree(qsa);
3995 drop_write:
3996 	mnt_drop_write_file(file);
3997 	return ret;
3998 }
3999 
4000 static long btrfs_ioctl_quota_rescan_status(struct btrfs_fs_info *fs_info,
4001 						void __user *arg)
4002 {
4003 	struct btrfs_ioctl_quota_rescan_args qsa = {0};
4004 
4005 	if (!capable(CAP_SYS_ADMIN))
4006 		return -EPERM;
4007 
4008 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
4009 		qsa.flags = 1;
4010 		qsa.progress = fs_info->qgroup_rescan_progress.objectid;
4011 	}
4012 
4013 	if (copy_to_user(arg, &qsa, sizeof(qsa)))
4014 		return -EFAULT;
4015 
4016 	return 0;
4017 }
4018 
4019 static long btrfs_ioctl_quota_rescan_wait(struct btrfs_fs_info *fs_info,
4020 						void __user *arg)
4021 {
4022 	if (!capable(CAP_SYS_ADMIN))
4023 		return -EPERM;
4024 
4025 	return btrfs_qgroup_wait_for_completion(fs_info, true);
4026 }
4027 
4028 static long _btrfs_ioctl_set_received_subvol(struct file *file,
4029 					    struct mnt_idmap *idmap,
4030 					    struct btrfs_ioctl_received_subvol_args *sa)
4031 {
4032 	struct inode *inode = file_inode(file);
4033 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4034 	struct btrfs_root *root = BTRFS_I(inode)->root;
4035 	struct btrfs_root_item *root_item = &root->root_item;
4036 	struct btrfs_trans_handle *trans;
4037 	struct timespec64 ct = current_time(inode);
4038 	int ret = 0;
4039 	int received_uuid_changed;
4040 
4041 	if (!inode_owner_or_capable(idmap, inode))
4042 		return -EPERM;
4043 
4044 	ret = mnt_want_write_file(file);
4045 	if (ret < 0)
4046 		return ret;
4047 
4048 	down_write(&fs_info->subvol_sem);
4049 
4050 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
4051 		ret = -EINVAL;
4052 		goto out;
4053 	}
4054 
4055 	if (btrfs_root_readonly(root)) {
4056 		ret = -EROFS;
4057 		goto out;
4058 	}
4059 
4060 	/*
4061 	 * 1 - root item
4062 	 * 2 - uuid items (received uuid + subvol uuid)
4063 	 */
4064 	trans = btrfs_start_transaction(root, 3);
4065 	if (IS_ERR(trans)) {
4066 		ret = PTR_ERR(trans);
4067 		trans = NULL;
4068 		goto out;
4069 	}
4070 
4071 	sa->rtransid = trans->transid;
4072 	sa->rtime.sec = ct.tv_sec;
4073 	sa->rtime.nsec = ct.tv_nsec;
4074 
4075 	received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
4076 				       BTRFS_UUID_SIZE);
4077 	if (received_uuid_changed &&
4078 	    !btrfs_is_empty_uuid(root_item->received_uuid)) {
4079 		ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid,
4080 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4081 					  btrfs_root_id(root));
4082 		if (ret && ret != -ENOENT) {
4083 		        btrfs_abort_transaction(trans, ret);
4084 		        btrfs_end_transaction(trans);
4085 		        goto out;
4086 		}
4087 	}
4088 	memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
4089 	btrfs_set_root_stransid(root_item, sa->stransid);
4090 	btrfs_set_root_rtransid(root_item, sa->rtransid);
4091 	btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
4092 	btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
4093 	btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
4094 	btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
4095 
4096 	ret = btrfs_update_root(trans, fs_info->tree_root,
4097 				&root->root_key, &root->root_item);
4098 	if (ret < 0) {
4099 		btrfs_end_transaction(trans);
4100 		goto out;
4101 	}
4102 	if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
4103 		ret = btrfs_uuid_tree_add(trans, sa->uuid,
4104 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4105 					  btrfs_root_id(root));
4106 		if (ret < 0 && ret != -EEXIST) {
4107 			btrfs_abort_transaction(trans, ret);
4108 			btrfs_end_transaction(trans);
4109 			goto out;
4110 		}
4111 	}
4112 	ret = btrfs_commit_transaction(trans);
4113 out:
4114 	up_write(&fs_info->subvol_sem);
4115 	mnt_drop_write_file(file);
4116 	return ret;
4117 }
4118 
4119 #ifdef CONFIG_64BIT
4120 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
4121 						void __user *arg)
4122 {
4123 	struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
4124 	struct btrfs_ioctl_received_subvol_args *args64 = NULL;
4125 	int ret = 0;
4126 
4127 	args32 = memdup_user(arg, sizeof(*args32));
4128 	if (IS_ERR(args32))
4129 		return PTR_ERR(args32);
4130 
4131 	args64 = kmalloc(sizeof(*args64), GFP_KERNEL);
4132 	if (!args64) {
4133 		ret = -ENOMEM;
4134 		goto out;
4135 	}
4136 
4137 	memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
4138 	args64->stransid = args32->stransid;
4139 	args64->rtransid = args32->rtransid;
4140 	args64->stime.sec = args32->stime.sec;
4141 	args64->stime.nsec = args32->stime.nsec;
4142 	args64->rtime.sec = args32->rtime.sec;
4143 	args64->rtime.nsec = args32->rtime.nsec;
4144 	args64->flags = args32->flags;
4145 
4146 	ret = _btrfs_ioctl_set_received_subvol(file, file_mnt_idmap(file), args64);
4147 	if (ret)
4148 		goto out;
4149 
4150 	memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
4151 	args32->stransid = args64->stransid;
4152 	args32->rtransid = args64->rtransid;
4153 	args32->stime.sec = args64->stime.sec;
4154 	args32->stime.nsec = args64->stime.nsec;
4155 	args32->rtime.sec = args64->rtime.sec;
4156 	args32->rtime.nsec = args64->rtime.nsec;
4157 	args32->flags = args64->flags;
4158 
4159 	ret = copy_to_user(arg, args32, sizeof(*args32));
4160 	if (ret)
4161 		ret = -EFAULT;
4162 
4163 out:
4164 	kfree(args32);
4165 	kfree(args64);
4166 	return ret;
4167 }
4168 #endif
4169 
4170 static long btrfs_ioctl_set_received_subvol(struct file *file,
4171 					    void __user *arg)
4172 {
4173 	struct btrfs_ioctl_received_subvol_args *sa = NULL;
4174 	int ret = 0;
4175 
4176 	sa = memdup_user(arg, sizeof(*sa));
4177 	if (IS_ERR(sa))
4178 		return PTR_ERR(sa);
4179 
4180 	ret = _btrfs_ioctl_set_received_subvol(file, file_mnt_idmap(file), sa);
4181 
4182 	if (ret)
4183 		goto out;
4184 
4185 	ret = copy_to_user(arg, sa, sizeof(*sa));
4186 	if (ret)
4187 		ret = -EFAULT;
4188 
4189 out:
4190 	kfree(sa);
4191 	return ret;
4192 }
4193 
4194 static int btrfs_ioctl_get_fslabel(struct btrfs_fs_info *fs_info,
4195 					void __user *arg)
4196 {
4197 	size_t len;
4198 	int ret;
4199 	char label[BTRFS_LABEL_SIZE];
4200 
4201 	spin_lock(&fs_info->super_lock);
4202 	memcpy(label, fs_info->super_copy->label, BTRFS_LABEL_SIZE);
4203 	spin_unlock(&fs_info->super_lock);
4204 
4205 	len = strnlen(label, BTRFS_LABEL_SIZE);
4206 
4207 	if (len == BTRFS_LABEL_SIZE) {
4208 		btrfs_warn(fs_info,
4209 			   "label is too long, return the first %zu bytes",
4210 			   --len);
4211 	}
4212 
4213 	ret = copy_to_user(arg, label, len);
4214 
4215 	return ret ? -EFAULT : 0;
4216 }
4217 
4218 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
4219 {
4220 	struct inode *inode = file_inode(file);
4221 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4222 	struct btrfs_root *root = BTRFS_I(inode)->root;
4223 	struct btrfs_super_block *super_block = fs_info->super_copy;
4224 	struct btrfs_trans_handle *trans;
4225 	char label[BTRFS_LABEL_SIZE];
4226 	int ret;
4227 
4228 	if (!capable(CAP_SYS_ADMIN))
4229 		return -EPERM;
4230 
4231 	if (copy_from_user(label, arg, sizeof(label)))
4232 		return -EFAULT;
4233 
4234 	if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
4235 		btrfs_err(fs_info,
4236 			  "unable to set label with more than %d bytes",
4237 			  BTRFS_LABEL_SIZE - 1);
4238 		return -EINVAL;
4239 	}
4240 
4241 	ret = mnt_want_write_file(file);
4242 	if (ret)
4243 		return ret;
4244 
4245 	trans = btrfs_start_transaction(root, 0);
4246 	if (IS_ERR(trans)) {
4247 		ret = PTR_ERR(trans);
4248 		goto out_unlock;
4249 	}
4250 
4251 	spin_lock(&fs_info->super_lock);
4252 	strcpy(super_block->label, label);
4253 	spin_unlock(&fs_info->super_lock);
4254 	ret = btrfs_commit_transaction(trans);
4255 
4256 out_unlock:
4257 	mnt_drop_write_file(file);
4258 	return ret;
4259 }
4260 
4261 #define INIT_FEATURE_FLAGS(suffix) \
4262 	{ .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
4263 	  .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
4264 	  .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
4265 
4266 int btrfs_ioctl_get_supported_features(void __user *arg)
4267 {
4268 	static const struct btrfs_ioctl_feature_flags features[3] = {
4269 		INIT_FEATURE_FLAGS(SUPP),
4270 		INIT_FEATURE_FLAGS(SAFE_SET),
4271 		INIT_FEATURE_FLAGS(SAFE_CLEAR)
4272 	};
4273 
4274 	if (copy_to_user(arg, &features, sizeof(features)))
4275 		return -EFAULT;
4276 
4277 	return 0;
4278 }
4279 
4280 static int btrfs_ioctl_get_features(struct btrfs_fs_info *fs_info,
4281 					void __user *arg)
4282 {
4283 	struct btrfs_super_block *super_block = fs_info->super_copy;
4284 	struct btrfs_ioctl_feature_flags features;
4285 
4286 	features.compat_flags = btrfs_super_compat_flags(super_block);
4287 	features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
4288 	features.incompat_flags = btrfs_super_incompat_flags(super_block);
4289 
4290 	if (copy_to_user(arg, &features, sizeof(features)))
4291 		return -EFAULT;
4292 
4293 	return 0;
4294 }
4295 
4296 static int check_feature_bits(struct btrfs_fs_info *fs_info,
4297 			      enum btrfs_feature_set set,
4298 			      u64 change_mask, u64 flags, u64 supported_flags,
4299 			      u64 safe_set, u64 safe_clear)
4300 {
4301 	const char *type = btrfs_feature_set_name(set);
4302 	char *names;
4303 	u64 disallowed, unsupported;
4304 	u64 set_mask = flags & change_mask;
4305 	u64 clear_mask = ~flags & change_mask;
4306 
4307 	unsupported = set_mask & ~supported_flags;
4308 	if (unsupported) {
4309 		names = btrfs_printable_features(set, unsupported);
4310 		if (names) {
4311 			btrfs_warn(fs_info,
4312 				   "this kernel does not support the %s feature bit%s",
4313 				   names, strchr(names, ',') ? "s" : "");
4314 			kfree(names);
4315 		} else
4316 			btrfs_warn(fs_info,
4317 				   "this kernel does not support %s bits 0x%llx",
4318 				   type, unsupported);
4319 		return -EOPNOTSUPP;
4320 	}
4321 
4322 	disallowed = set_mask & ~safe_set;
4323 	if (disallowed) {
4324 		names = btrfs_printable_features(set, disallowed);
4325 		if (names) {
4326 			btrfs_warn(fs_info,
4327 				   "can't set the %s feature bit%s while mounted",
4328 				   names, strchr(names, ',') ? "s" : "");
4329 			kfree(names);
4330 		} else
4331 			btrfs_warn(fs_info,
4332 				   "can't set %s bits 0x%llx while mounted",
4333 				   type, disallowed);
4334 		return -EPERM;
4335 	}
4336 
4337 	disallowed = clear_mask & ~safe_clear;
4338 	if (disallowed) {
4339 		names = btrfs_printable_features(set, disallowed);
4340 		if (names) {
4341 			btrfs_warn(fs_info,
4342 				   "can't clear the %s feature bit%s while mounted",
4343 				   names, strchr(names, ',') ? "s" : "");
4344 			kfree(names);
4345 		} else
4346 			btrfs_warn(fs_info,
4347 				   "can't clear %s bits 0x%llx while mounted",
4348 				   type, disallowed);
4349 		return -EPERM;
4350 	}
4351 
4352 	return 0;
4353 }
4354 
4355 #define check_feature(fs_info, change_mask, flags, mask_base)	\
4356 check_feature_bits(fs_info, FEAT_##mask_base, change_mask, flags,	\
4357 		   BTRFS_FEATURE_ ## mask_base ## _SUPP,	\
4358 		   BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,	\
4359 		   BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
4360 
4361 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
4362 {
4363 	struct inode *inode = file_inode(file);
4364 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4365 	struct btrfs_root *root = BTRFS_I(inode)->root;
4366 	struct btrfs_super_block *super_block = fs_info->super_copy;
4367 	struct btrfs_ioctl_feature_flags flags[2];
4368 	struct btrfs_trans_handle *trans;
4369 	u64 newflags;
4370 	int ret;
4371 
4372 	if (!capable(CAP_SYS_ADMIN))
4373 		return -EPERM;
4374 
4375 	if (copy_from_user(flags, arg, sizeof(flags)))
4376 		return -EFAULT;
4377 
4378 	/* Nothing to do */
4379 	if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
4380 	    !flags[0].incompat_flags)
4381 		return 0;
4382 
4383 	ret = check_feature(fs_info, flags[0].compat_flags,
4384 			    flags[1].compat_flags, COMPAT);
4385 	if (ret)
4386 		return ret;
4387 
4388 	ret = check_feature(fs_info, flags[0].compat_ro_flags,
4389 			    flags[1].compat_ro_flags, COMPAT_RO);
4390 	if (ret)
4391 		return ret;
4392 
4393 	ret = check_feature(fs_info, flags[0].incompat_flags,
4394 			    flags[1].incompat_flags, INCOMPAT);
4395 	if (ret)
4396 		return ret;
4397 
4398 	ret = mnt_want_write_file(file);
4399 	if (ret)
4400 		return ret;
4401 
4402 	trans = btrfs_start_transaction(root, 0);
4403 	if (IS_ERR(trans)) {
4404 		ret = PTR_ERR(trans);
4405 		goto out_drop_write;
4406 	}
4407 
4408 	spin_lock(&fs_info->super_lock);
4409 	newflags = btrfs_super_compat_flags(super_block);
4410 	newflags |= flags[0].compat_flags & flags[1].compat_flags;
4411 	newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
4412 	btrfs_set_super_compat_flags(super_block, newflags);
4413 
4414 	newflags = btrfs_super_compat_ro_flags(super_block);
4415 	newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
4416 	newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
4417 	btrfs_set_super_compat_ro_flags(super_block, newflags);
4418 
4419 	newflags = btrfs_super_incompat_flags(super_block);
4420 	newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
4421 	newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
4422 	btrfs_set_super_incompat_flags(super_block, newflags);
4423 	spin_unlock(&fs_info->super_lock);
4424 
4425 	ret = btrfs_commit_transaction(trans);
4426 out_drop_write:
4427 	mnt_drop_write_file(file);
4428 
4429 	return ret;
4430 }
4431 
4432 static int _btrfs_ioctl_send(struct inode *inode, void __user *argp, bool compat)
4433 {
4434 	struct btrfs_ioctl_send_args *arg;
4435 	int ret;
4436 
4437 	if (compat) {
4438 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4439 		struct btrfs_ioctl_send_args_32 args32 = { 0 };
4440 
4441 		ret = copy_from_user(&args32, argp, sizeof(args32));
4442 		if (ret)
4443 			return -EFAULT;
4444 		arg = kzalloc(sizeof(*arg), GFP_KERNEL);
4445 		if (!arg)
4446 			return -ENOMEM;
4447 		arg->send_fd = args32.send_fd;
4448 		arg->clone_sources_count = args32.clone_sources_count;
4449 		arg->clone_sources = compat_ptr(args32.clone_sources);
4450 		arg->parent_root = args32.parent_root;
4451 		arg->flags = args32.flags;
4452 		arg->version = args32.version;
4453 		memcpy(arg->reserved, args32.reserved,
4454 		       sizeof(args32.reserved));
4455 #else
4456 		return -ENOTTY;
4457 #endif
4458 	} else {
4459 		arg = memdup_user(argp, sizeof(*arg));
4460 		if (IS_ERR(arg))
4461 			return PTR_ERR(arg);
4462 	}
4463 	ret = btrfs_ioctl_send(inode, arg);
4464 	kfree(arg);
4465 	return ret;
4466 }
4467 
4468 static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
4469 				    bool compat)
4470 {
4471 	struct btrfs_ioctl_encoded_io_args args = { 0 };
4472 	size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args,
4473 					     flags);
4474 	size_t copy_end;
4475 	struct iovec iovstack[UIO_FASTIOV];
4476 	struct iovec *iov = iovstack;
4477 	struct iov_iter iter;
4478 	loff_t pos;
4479 	struct kiocb kiocb;
4480 	ssize_t ret;
4481 
4482 	if (!capable(CAP_SYS_ADMIN)) {
4483 		ret = -EPERM;
4484 		goto out_acct;
4485 	}
4486 
4487 	if (compat) {
4488 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4489 		struct btrfs_ioctl_encoded_io_args_32 args32;
4490 
4491 		copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32,
4492 				       flags);
4493 		if (copy_from_user(&args32, argp, copy_end)) {
4494 			ret = -EFAULT;
4495 			goto out_acct;
4496 		}
4497 		args.iov = compat_ptr(args32.iov);
4498 		args.iovcnt = args32.iovcnt;
4499 		args.offset = args32.offset;
4500 		args.flags = args32.flags;
4501 #else
4502 		return -ENOTTY;
4503 #endif
4504 	} else {
4505 		copy_end = copy_end_kernel;
4506 		if (copy_from_user(&args, argp, copy_end)) {
4507 			ret = -EFAULT;
4508 			goto out_acct;
4509 		}
4510 	}
4511 	if (args.flags != 0) {
4512 		ret = -EINVAL;
4513 		goto out_acct;
4514 	}
4515 
4516 	ret = import_iovec(ITER_DEST, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
4517 			   &iov, &iter);
4518 	if (ret < 0)
4519 		goto out_acct;
4520 
4521 	if (iov_iter_count(&iter) == 0) {
4522 		ret = 0;
4523 		goto out_iov;
4524 	}
4525 	pos = args.offset;
4526 	ret = rw_verify_area(READ, file, &pos, args.len);
4527 	if (ret < 0)
4528 		goto out_iov;
4529 
4530 	init_sync_kiocb(&kiocb, file);
4531 	kiocb.ki_pos = pos;
4532 
4533 	ret = btrfs_encoded_read(&kiocb, &iter, &args);
4534 	if (ret >= 0) {
4535 		fsnotify_access(file);
4536 		if (copy_to_user(argp + copy_end,
4537 				 (char *)&args + copy_end_kernel,
4538 				 sizeof(args) - copy_end_kernel))
4539 			ret = -EFAULT;
4540 	}
4541 
4542 out_iov:
4543 	kfree(iov);
4544 out_acct:
4545 	if (ret > 0)
4546 		add_rchar(current, ret);
4547 	inc_syscr(current);
4548 	return ret;
4549 }
4550 
4551 static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp, bool compat)
4552 {
4553 	struct btrfs_ioctl_encoded_io_args args;
4554 	struct iovec iovstack[UIO_FASTIOV];
4555 	struct iovec *iov = iovstack;
4556 	struct iov_iter iter;
4557 	loff_t pos;
4558 	struct kiocb kiocb;
4559 	ssize_t ret;
4560 
4561 	if (!capable(CAP_SYS_ADMIN)) {
4562 		ret = -EPERM;
4563 		goto out_acct;
4564 	}
4565 
4566 	if (!(file->f_mode & FMODE_WRITE)) {
4567 		ret = -EBADF;
4568 		goto out_acct;
4569 	}
4570 
4571 	if (compat) {
4572 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4573 		struct btrfs_ioctl_encoded_io_args_32 args32;
4574 
4575 		if (copy_from_user(&args32, argp, sizeof(args32))) {
4576 			ret = -EFAULT;
4577 			goto out_acct;
4578 		}
4579 		args.iov = compat_ptr(args32.iov);
4580 		args.iovcnt = args32.iovcnt;
4581 		args.offset = args32.offset;
4582 		args.flags = args32.flags;
4583 		args.len = args32.len;
4584 		args.unencoded_len = args32.unencoded_len;
4585 		args.unencoded_offset = args32.unencoded_offset;
4586 		args.compression = args32.compression;
4587 		args.encryption = args32.encryption;
4588 		memcpy(args.reserved, args32.reserved, sizeof(args.reserved));
4589 #else
4590 		return -ENOTTY;
4591 #endif
4592 	} else {
4593 		if (copy_from_user(&args, argp, sizeof(args))) {
4594 			ret = -EFAULT;
4595 			goto out_acct;
4596 		}
4597 	}
4598 
4599 	ret = -EINVAL;
4600 	if (args.flags != 0)
4601 		goto out_acct;
4602 	if (memchr_inv(args.reserved, 0, sizeof(args.reserved)))
4603 		goto out_acct;
4604 	if (args.compression == BTRFS_ENCODED_IO_COMPRESSION_NONE &&
4605 	    args.encryption == BTRFS_ENCODED_IO_ENCRYPTION_NONE)
4606 		goto out_acct;
4607 	if (args.compression >= BTRFS_ENCODED_IO_COMPRESSION_TYPES ||
4608 	    args.encryption >= BTRFS_ENCODED_IO_ENCRYPTION_TYPES)
4609 		goto out_acct;
4610 	if (args.unencoded_offset > args.unencoded_len)
4611 		goto out_acct;
4612 	if (args.len > args.unencoded_len - args.unencoded_offset)
4613 		goto out_acct;
4614 
4615 	ret = import_iovec(ITER_SOURCE, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
4616 			   &iov, &iter);
4617 	if (ret < 0)
4618 		goto out_acct;
4619 
4620 	if (iov_iter_count(&iter) == 0) {
4621 		ret = 0;
4622 		goto out_iov;
4623 	}
4624 	pos = args.offset;
4625 	ret = rw_verify_area(WRITE, file, &pos, args.len);
4626 	if (ret < 0)
4627 		goto out_iov;
4628 
4629 	init_sync_kiocb(&kiocb, file);
4630 	ret = kiocb_set_rw_flags(&kiocb, 0);
4631 	if (ret)
4632 		goto out_iov;
4633 	kiocb.ki_pos = pos;
4634 
4635 	file_start_write(file);
4636 
4637 	ret = btrfs_do_write_iter(&kiocb, &iter, &args);
4638 	if (ret > 0)
4639 		fsnotify_modify(file);
4640 
4641 	file_end_write(file);
4642 out_iov:
4643 	kfree(iov);
4644 out_acct:
4645 	if (ret > 0)
4646 		add_wchar(current, ret);
4647 	inc_syscw(current);
4648 	return ret;
4649 }
4650 
4651 long btrfs_ioctl(struct file *file, unsigned int
4652 		cmd, unsigned long arg)
4653 {
4654 	struct inode *inode = file_inode(file);
4655 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4656 	struct btrfs_root *root = BTRFS_I(inode)->root;
4657 	void __user *argp = (void __user *)arg;
4658 
4659 	switch (cmd) {
4660 	case FS_IOC_GETVERSION:
4661 		return btrfs_ioctl_getversion(inode, argp);
4662 	case FS_IOC_GETFSLABEL:
4663 		return btrfs_ioctl_get_fslabel(fs_info, argp);
4664 	case FS_IOC_SETFSLABEL:
4665 		return btrfs_ioctl_set_fslabel(file, argp);
4666 	case FITRIM:
4667 		return btrfs_ioctl_fitrim(fs_info, argp);
4668 	case BTRFS_IOC_SNAP_CREATE:
4669 		return btrfs_ioctl_snap_create(file, argp, 0);
4670 	case BTRFS_IOC_SNAP_CREATE_V2:
4671 		return btrfs_ioctl_snap_create_v2(file, argp, 0);
4672 	case BTRFS_IOC_SUBVOL_CREATE:
4673 		return btrfs_ioctl_snap_create(file, argp, 1);
4674 	case BTRFS_IOC_SUBVOL_CREATE_V2:
4675 		return btrfs_ioctl_snap_create_v2(file, argp, 1);
4676 	case BTRFS_IOC_SNAP_DESTROY:
4677 		return btrfs_ioctl_snap_destroy(file, argp, false);
4678 	case BTRFS_IOC_SNAP_DESTROY_V2:
4679 		return btrfs_ioctl_snap_destroy(file, argp, true);
4680 	case BTRFS_IOC_SUBVOL_GETFLAGS:
4681 		return btrfs_ioctl_subvol_getflags(inode, argp);
4682 	case BTRFS_IOC_SUBVOL_SETFLAGS:
4683 		return btrfs_ioctl_subvol_setflags(file, argp);
4684 	case BTRFS_IOC_DEFAULT_SUBVOL:
4685 		return btrfs_ioctl_default_subvol(file, argp);
4686 	case BTRFS_IOC_DEFRAG:
4687 		return btrfs_ioctl_defrag(file, NULL);
4688 	case BTRFS_IOC_DEFRAG_RANGE:
4689 		return btrfs_ioctl_defrag(file, argp);
4690 	case BTRFS_IOC_RESIZE:
4691 		return btrfs_ioctl_resize(file, argp);
4692 	case BTRFS_IOC_ADD_DEV:
4693 		return btrfs_ioctl_add_dev(fs_info, argp);
4694 	case BTRFS_IOC_RM_DEV:
4695 		return btrfs_ioctl_rm_dev(file, argp);
4696 	case BTRFS_IOC_RM_DEV_V2:
4697 		return btrfs_ioctl_rm_dev_v2(file, argp);
4698 	case BTRFS_IOC_FS_INFO:
4699 		return btrfs_ioctl_fs_info(fs_info, argp);
4700 	case BTRFS_IOC_DEV_INFO:
4701 		return btrfs_ioctl_dev_info(fs_info, argp);
4702 	case BTRFS_IOC_TREE_SEARCH:
4703 		return btrfs_ioctl_tree_search(inode, argp);
4704 	case BTRFS_IOC_TREE_SEARCH_V2:
4705 		return btrfs_ioctl_tree_search_v2(inode, argp);
4706 	case BTRFS_IOC_INO_LOOKUP:
4707 		return btrfs_ioctl_ino_lookup(root, argp);
4708 	case BTRFS_IOC_INO_PATHS:
4709 		return btrfs_ioctl_ino_to_path(root, argp);
4710 	case BTRFS_IOC_LOGICAL_INO:
4711 		return btrfs_ioctl_logical_to_ino(fs_info, argp, 1);
4712 	case BTRFS_IOC_LOGICAL_INO_V2:
4713 		return btrfs_ioctl_logical_to_ino(fs_info, argp, 2);
4714 	case BTRFS_IOC_SPACE_INFO:
4715 		return btrfs_ioctl_space_info(fs_info, argp);
4716 	case BTRFS_IOC_SYNC: {
4717 		int ret;
4718 
4719 		ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
4720 		if (ret)
4721 			return ret;
4722 		ret = btrfs_sync_fs(inode->i_sb, 1);
4723 		/*
4724 		 * The transaction thread may want to do more work,
4725 		 * namely it pokes the cleaner kthread that will start
4726 		 * processing uncleaned subvols.
4727 		 */
4728 		wake_up_process(fs_info->transaction_kthread);
4729 		return ret;
4730 	}
4731 	case BTRFS_IOC_START_SYNC:
4732 		return btrfs_ioctl_start_sync(root, argp);
4733 	case BTRFS_IOC_WAIT_SYNC:
4734 		return btrfs_ioctl_wait_sync(fs_info, argp);
4735 	case BTRFS_IOC_SCRUB:
4736 		return btrfs_ioctl_scrub(file, argp);
4737 	case BTRFS_IOC_SCRUB_CANCEL:
4738 		return btrfs_ioctl_scrub_cancel(fs_info);
4739 	case BTRFS_IOC_SCRUB_PROGRESS:
4740 		return btrfs_ioctl_scrub_progress(fs_info, argp);
4741 	case BTRFS_IOC_BALANCE_V2:
4742 		return btrfs_ioctl_balance(file, argp);
4743 	case BTRFS_IOC_BALANCE_CTL:
4744 		return btrfs_ioctl_balance_ctl(fs_info, arg);
4745 	case BTRFS_IOC_BALANCE_PROGRESS:
4746 		return btrfs_ioctl_balance_progress(fs_info, argp);
4747 	case BTRFS_IOC_SET_RECEIVED_SUBVOL:
4748 		return btrfs_ioctl_set_received_subvol(file, argp);
4749 #ifdef CONFIG_64BIT
4750 	case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
4751 		return btrfs_ioctl_set_received_subvol_32(file, argp);
4752 #endif
4753 	case BTRFS_IOC_SEND:
4754 		return _btrfs_ioctl_send(inode, argp, false);
4755 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4756 	case BTRFS_IOC_SEND_32:
4757 		return _btrfs_ioctl_send(inode, argp, true);
4758 #endif
4759 	case BTRFS_IOC_GET_DEV_STATS:
4760 		return btrfs_ioctl_get_dev_stats(fs_info, argp);
4761 	case BTRFS_IOC_QUOTA_CTL:
4762 		return btrfs_ioctl_quota_ctl(file, argp);
4763 	case BTRFS_IOC_QGROUP_ASSIGN:
4764 		return btrfs_ioctl_qgroup_assign(file, argp);
4765 	case BTRFS_IOC_QGROUP_CREATE:
4766 		return btrfs_ioctl_qgroup_create(file, argp);
4767 	case BTRFS_IOC_QGROUP_LIMIT:
4768 		return btrfs_ioctl_qgroup_limit(file, argp);
4769 	case BTRFS_IOC_QUOTA_RESCAN:
4770 		return btrfs_ioctl_quota_rescan(file, argp);
4771 	case BTRFS_IOC_QUOTA_RESCAN_STATUS:
4772 		return btrfs_ioctl_quota_rescan_status(fs_info, argp);
4773 	case BTRFS_IOC_QUOTA_RESCAN_WAIT:
4774 		return btrfs_ioctl_quota_rescan_wait(fs_info, argp);
4775 	case BTRFS_IOC_DEV_REPLACE:
4776 		return btrfs_ioctl_dev_replace(fs_info, argp);
4777 	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
4778 		return btrfs_ioctl_get_supported_features(argp);
4779 	case BTRFS_IOC_GET_FEATURES:
4780 		return btrfs_ioctl_get_features(fs_info, argp);
4781 	case BTRFS_IOC_SET_FEATURES:
4782 		return btrfs_ioctl_set_features(file, argp);
4783 	case BTRFS_IOC_GET_SUBVOL_INFO:
4784 		return btrfs_ioctl_get_subvol_info(inode, argp);
4785 	case BTRFS_IOC_GET_SUBVOL_ROOTREF:
4786 		return btrfs_ioctl_get_subvol_rootref(root, argp);
4787 	case BTRFS_IOC_INO_LOOKUP_USER:
4788 		return btrfs_ioctl_ino_lookup_user(file, argp);
4789 	case FS_IOC_ENABLE_VERITY:
4790 		return fsverity_ioctl_enable(file, (const void __user *)argp);
4791 	case FS_IOC_MEASURE_VERITY:
4792 		return fsverity_ioctl_measure(file, argp);
4793 	case BTRFS_IOC_ENCODED_READ:
4794 		return btrfs_ioctl_encoded_read(file, argp, false);
4795 	case BTRFS_IOC_ENCODED_WRITE:
4796 		return btrfs_ioctl_encoded_write(file, argp, false);
4797 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4798 	case BTRFS_IOC_ENCODED_READ_32:
4799 		return btrfs_ioctl_encoded_read(file, argp, true);
4800 	case BTRFS_IOC_ENCODED_WRITE_32:
4801 		return btrfs_ioctl_encoded_write(file, argp, true);
4802 #endif
4803 	}
4804 
4805 	return -ENOTTY;
4806 }
4807 
4808 #ifdef CONFIG_COMPAT
4809 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4810 {
4811 	/*
4812 	 * These all access 32-bit values anyway so no further
4813 	 * handling is necessary.
4814 	 */
4815 	switch (cmd) {
4816 	case FS_IOC32_GETVERSION:
4817 		cmd = FS_IOC_GETVERSION;
4818 		break;
4819 	}
4820 
4821 	return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
4822 }
4823 #endif
4824