xref: /openbmc/linux/fs/btrfs/ioctl.c (revision 4b0aaacee51eb6592a03fdefd5ce97558518e291)
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 "ctree.h"
30 #include "disk-io.h"
31 #include "transaction.h"
32 #include "btrfs_inode.h"
33 #include "print-tree.h"
34 #include "volumes.h"
35 #include "locking.h"
36 #include "inode-map.h"
37 #include "backref.h"
38 #include "rcu-string.h"
39 #include "send.h"
40 #include "dev-replace.h"
41 #include "props.h"
42 #include "sysfs.h"
43 #include "qgroup.h"
44 #include "tree-log.h"
45 #include "compression.h"
46 
47 #ifdef CONFIG_64BIT
48 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
49  * structures are incorrect, as the timespec structure from userspace
50  * is 4 bytes too small. We define these alternatives here to teach
51  * the kernel about the 32-bit struct packing.
52  */
53 struct btrfs_ioctl_timespec_32 {
54 	__u64 sec;
55 	__u32 nsec;
56 } __attribute__ ((__packed__));
57 
58 struct btrfs_ioctl_received_subvol_args_32 {
59 	char	uuid[BTRFS_UUID_SIZE];	/* in */
60 	__u64	stransid;		/* in */
61 	__u64	rtransid;		/* out */
62 	struct btrfs_ioctl_timespec_32 stime; /* in */
63 	struct btrfs_ioctl_timespec_32 rtime; /* out */
64 	__u64	flags;			/* in */
65 	__u64	reserved[16];		/* in */
66 } __attribute__ ((__packed__));
67 
68 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
69 				struct btrfs_ioctl_received_subvol_args_32)
70 #endif
71 
72 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
73 struct btrfs_ioctl_send_args_32 {
74 	__s64 send_fd;			/* in */
75 	__u64 clone_sources_count;	/* in */
76 	compat_uptr_t clone_sources;	/* in */
77 	__u64 parent_root;		/* in */
78 	__u64 flags;			/* in */
79 	__u64 reserved[4];		/* in */
80 } __attribute__ ((__packed__));
81 
82 #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \
83 			       struct btrfs_ioctl_send_args_32)
84 #endif
85 
86 static int btrfs_clone(struct inode *src, struct inode *inode,
87 		       u64 off, u64 olen, u64 olen_aligned, u64 destoff,
88 		       int no_time_update);
89 
90 /* Mask out flags that are inappropriate for the given type of inode. */
91 static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
92 		unsigned int flags)
93 {
94 	if (S_ISDIR(inode->i_mode))
95 		return flags;
96 	else if (S_ISREG(inode->i_mode))
97 		return flags & ~FS_DIRSYNC_FL;
98 	else
99 		return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
100 }
101 
102 /*
103  * Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
104  * ioctl.
105  */
106 static unsigned int btrfs_inode_flags_to_fsflags(unsigned int flags)
107 {
108 	unsigned int iflags = 0;
109 
110 	if (flags & BTRFS_INODE_SYNC)
111 		iflags |= FS_SYNC_FL;
112 	if (flags & BTRFS_INODE_IMMUTABLE)
113 		iflags |= FS_IMMUTABLE_FL;
114 	if (flags & BTRFS_INODE_APPEND)
115 		iflags |= FS_APPEND_FL;
116 	if (flags & BTRFS_INODE_NODUMP)
117 		iflags |= FS_NODUMP_FL;
118 	if (flags & BTRFS_INODE_NOATIME)
119 		iflags |= FS_NOATIME_FL;
120 	if (flags & BTRFS_INODE_DIRSYNC)
121 		iflags |= FS_DIRSYNC_FL;
122 	if (flags & BTRFS_INODE_NODATACOW)
123 		iflags |= FS_NOCOW_FL;
124 
125 	if (flags & BTRFS_INODE_NOCOMPRESS)
126 		iflags |= FS_NOCOMP_FL;
127 	else if (flags & BTRFS_INODE_COMPRESS)
128 		iflags |= FS_COMPR_FL;
129 
130 	return iflags;
131 }
132 
133 /*
134  * Update inode->i_flags based on the btrfs internal flags.
135  */
136 void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
137 {
138 	struct btrfs_inode *binode = BTRFS_I(inode);
139 	unsigned int new_fl = 0;
140 
141 	if (binode->flags & BTRFS_INODE_SYNC)
142 		new_fl |= S_SYNC;
143 	if (binode->flags & BTRFS_INODE_IMMUTABLE)
144 		new_fl |= S_IMMUTABLE;
145 	if (binode->flags & BTRFS_INODE_APPEND)
146 		new_fl |= S_APPEND;
147 	if (binode->flags & BTRFS_INODE_NOATIME)
148 		new_fl |= S_NOATIME;
149 	if (binode->flags & BTRFS_INODE_DIRSYNC)
150 		new_fl |= S_DIRSYNC;
151 
152 	set_mask_bits(&inode->i_flags,
153 		      S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
154 		      new_fl);
155 }
156 
157 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
158 {
159 	struct btrfs_inode *binode = BTRFS_I(file_inode(file));
160 	unsigned int flags = btrfs_inode_flags_to_fsflags(binode->flags);
161 
162 	if (copy_to_user(arg, &flags, sizeof(flags)))
163 		return -EFAULT;
164 	return 0;
165 }
166 
167 /* Check if @flags are a supported and valid set of FS_*_FL flags */
168 static int check_fsflags(unsigned int flags)
169 {
170 	if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
171 		      FS_NOATIME_FL | FS_NODUMP_FL | \
172 		      FS_SYNC_FL | FS_DIRSYNC_FL | \
173 		      FS_NOCOMP_FL | FS_COMPR_FL |
174 		      FS_NOCOW_FL))
175 		return -EOPNOTSUPP;
176 
177 	if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
178 		return -EINVAL;
179 
180 	return 0;
181 }
182 
183 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
184 {
185 	struct inode *inode = file_inode(file);
186 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
187 	struct btrfs_inode *binode = BTRFS_I(inode);
188 	struct btrfs_root *root = binode->root;
189 	struct btrfs_trans_handle *trans;
190 	unsigned int fsflags, old_fsflags;
191 	int ret;
192 	u64 old_flags;
193 	unsigned int old_i_flags;
194 	umode_t mode;
195 
196 	if (!inode_owner_or_capable(inode))
197 		return -EPERM;
198 
199 	if (btrfs_root_readonly(root))
200 		return -EROFS;
201 
202 	if (copy_from_user(&fsflags, arg, sizeof(fsflags)))
203 		return -EFAULT;
204 
205 	ret = check_fsflags(fsflags);
206 	if (ret)
207 		return ret;
208 
209 	ret = mnt_want_write_file(file);
210 	if (ret)
211 		return ret;
212 
213 	inode_lock(inode);
214 
215 	old_flags = binode->flags;
216 	old_i_flags = inode->i_flags;
217 	mode = inode->i_mode;
218 
219 	fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
220 	old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
221 	if ((fsflags ^ old_fsflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
222 		if (!capable(CAP_LINUX_IMMUTABLE)) {
223 			ret = -EPERM;
224 			goto out_unlock;
225 		}
226 	}
227 
228 	if (fsflags & FS_SYNC_FL)
229 		binode->flags |= BTRFS_INODE_SYNC;
230 	else
231 		binode->flags &= ~BTRFS_INODE_SYNC;
232 	if (fsflags & FS_IMMUTABLE_FL)
233 		binode->flags |= BTRFS_INODE_IMMUTABLE;
234 	else
235 		binode->flags &= ~BTRFS_INODE_IMMUTABLE;
236 	if (fsflags & FS_APPEND_FL)
237 		binode->flags |= BTRFS_INODE_APPEND;
238 	else
239 		binode->flags &= ~BTRFS_INODE_APPEND;
240 	if (fsflags & FS_NODUMP_FL)
241 		binode->flags |= BTRFS_INODE_NODUMP;
242 	else
243 		binode->flags &= ~BTRFS_INODE_NODUMP;
244 	if (fsflags & FS_NOATIME_FL)
245 		binode->flags |= BTRFS_INODE_NOATIME;
246 	else
247 		binode->flags &= ~BTRFS_INODE_NOATIME;
248 	if (fsflags & FS_DIRSYNC_FL)
249 		binode->flags |= BTRFS_INODE_DIRSYNC;
250 	else
251 		binode->flags &= ~BTRFS_INODE_DIRSYNC;
252 	if (fsflags & FS_NOCOW_FL) {
253 		if (S_ISREG(mode)) {
254 			/*
255 			 * It's safe to turn csums off here, no extents exist.
256 			 * Otherwise we want the flag to reflect the real COW
257 			 * status of the file and will not set it.
258 			 */
259 			if (inode->i_size == 0)
260 				binode->flags |= BTRFS_INODE_NODATACOW
261 					      | BTRFS_INODE_NODATASUM;
262 		} else {
263 			binode->flags |= BTRFS_INODE_NODATACOW;
264 		}
265 	} else {
266 		/*
267 		 * Revert back under same assumptions as above
268 		 */
269 		if (S_ISREG(mode)) {
270 			if (inode->i_size == 0)
271 				binode->flags &= ~(BTRFS_INODE_NODATACOW
272 				             | BTRFS_INODE_NODATASUM);
273 		} else {
274 			binode->flags &= ~BTRFS_INODE_NODATACOW;
275 		}
276 	}
277 
278 	/*
279 	 * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
280 	 * flag may be changed automatically if compression code won't make
281 	 * things smaller.
282 	 */
283 	if (fsflags & FS_NOCOMP_FL) {
284 		binode->flags &= ~BTRFS_INODE_COMPRESS;
285 		binode->flags |= BTRFS_INODE_NOCOMPRESS;
286 
287 		ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
288 		if (ret && ret != -ENODATA)
289 			goto out_drop;
290 	} else if (fsflags & FS_COMPR_FL) {
291 		const char *comp;
292 
293 		binode->flags |= BTRFS_INODE_COMPRESS;
294 		binode->flags &= ~BTRFS_INODE_NOCOMPRESS;
295 
296 		comp = btrfs_compress_type2str(fs_info->compress_type);
297 		if (!comp || comp[0] == 0)
298 			comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
299 
300 		ret = btrfs_set_prop(inode, "btrfs.compression",
301 				     comp, strlen(comp), 0);
302 		if (ret)
303 			goto out_drop;
304 
305 	} else {
306 		ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
307 		if (ret && ret != -ENODATA)
308 			goto out_drop;
309 		binode->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
310 	}
311 
312 	trans = btrfs_start_transaction(root, 1);
313 	if (IS_ERR(trans)) {
314 		ret = PTR_ERR(trans);
315 		goto out_drop;
316 	}
317 
318 	btrfs_sync_inode_flags_to_i_flags(inode);
319 	inode_inc_iversion(inode);
320 	inode->i_ctime = current_time(inode);
321 	ret = btrfs_update_inode(trans, root, inode);
322 
323 	btrfs_end_transaction(trans);
324  out_drop:
325 	if (ret) {
326 		binode->flags = old_flags;
327 		inode->i_flags = old_i_flags;
328 	}
329 
330  out_unlock:
331 	inode_unlock(inode);
332 	mnt_drop_write_file(file);
333 	return ret;
334 }
335 
336 /*
337  * Translate btrfs internal inode flags to xflags as expected by the
338  * FS_IOC_FSGETXATT ioctl. Filter only the supported ones, unknown flags are
339  * silently dropped.
340  */
341 static unsigned int btrfs_inode_flags_to_xflags(unsigned int flags)
342 {
343 	unsigned int xflags = 0;
344 
345 	if (flags & BTRFS_INODE_APPEND)
346 		xflags |= FS_XFLAG_APPEND;
347 	if (flags & BTRFS_INODE_IMMUTABLE)
348 		xflags |= FS_XFLAG_IMMUTABLE;
349 	if (flags & BTRFS_INODE_NOATIME)
350 		xflags |= FS_XFLAG_NOATIME;
351 	if (flags & BTRFS_INODE_NODUMP)
352 		xflags |= FS_XFLAG_NODUMP;
353 	if (flags & BTRFS_INODE_SYNC)
354 		xflags |= FS_XFLAG_SYNC;
355 
356 	return xflags;
357 }
358 
359 /* Check if @flags are a supported and valid set of FS_XFLAGS_* flags */
360 static int check_xflags(unsigned int flags)
361 {
362 	if (flags & ~(FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE | FS_XFLAG_NOATIME |
363 		      FS_XFLAG_NODUMP | FS_XFLAG_SYNC))
364 		return -EOPNOTSUPP;
365 	return 0;
366 }
367 
368 /*
369  * Set the xflags from the internal inode flags. The remaining items of fsxattr
370  * are zeroed.
371  */
372 static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
373 {
374 	struct btrfs_inode *binode = BTRFS_I(file_inode(file));
375 	struct fsxattr fa;
376 
377 	memset(&fa, 0, sizeof(fa));
378 	fa.fsx_xflags = btrfs_inode_flags_to_xflags(binode->flags);
379 
380 	if (copy_to_user(arg, &fa, sizeof(fa)))
381 		return -EFAULT;
382 
383 	return 0;
384 }
385 
386 static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
387 {
388 	struct inode *inode = file_inode(file);
389 	struct btrfs_inode *binode = BTRFS_I(inode);
390 	struct btrfs_root *root = binode->root;
391 	struct btrfs_trans_handle *trans;
392 	struct fsxattr fa;
393 	unsigned old_flags;
394 	unsigned old_i_flags;
395 	int ret = 0;
396 
397 	if (!inode_owner_or_capable(inode))
398 		return -EPERM;
399 
400 	if (btrfs_root_readonly(root))
401 		return -EROFS;
402 
403 	memset(&fa, 0, sizeof(fa));
404 	if (copy_from_user(&fa, arg, sizeof(fa)))
405 		return -EFAULT;
406 
407 	ret = check_xflags(fa.fsx_xflags);
408 	if (ret)
409 		return ret;
410 
411 	if (fa.fsx_extsize != 0 || fa.fsx_projid != 0 || fa.fsx_cowextsize != 0)
412 		return -EOPNOTSUPP;
413 
414 	ret = mnt_want_write_file(file);
415 	if (ret)
416 		return ret;
417 
418 	inode_lock(inode);
419 
420 	old_flags = binode->flags;
421 	old_i_flags = inode->i_flags;
422 
423 	/* We need the capabilities to change append-only or immutable inode */
424 	if (((old_flags & (BTRFS_INODE_APPEND | BTRFS_INODE_IMMUTABLE)) ||
425 	     (fa.fsx_xflags & (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE))) &&
426 	    !capable(CAP_LINUX_IMMUTABLE)) {
427 		ret = -EPERM;
428 		goto out_unlock;
429 	}
430 
431 	if (fa.fsx_xflags & FS_XFLAG_SYNC)
432 		binode->flags |= BTRFS_INODE_SYNC;
433 	else
434 		binode->flags &= ~BTRFS_INODE_SYNC;
435 	if (fa.fsx_xflags & FS_XFLAG_IMMUTABLE)
436 		binode->flags |= BTRFS_INODE_IMMUTABLE;
437 	else
438 		binode->flags &= ~BTRFS_INODE_IMMUTABLE;
439 	if (fa.fsx_xflags & FS_XFLAG_APPEND)
440 		binode->flags |= BTRFS_INODE_APPEND;
441 	else
442 		binode->flags &= ~BTRFS_INODE_APPEND;
443 	if (fa.fsx_xflags & FS_XFLAG_NODUMP)
444 		binode->flags |= BTRFS_INODE_NODUMP;
445 	else
446 		binode->flags &= ~BTRFS_INODE_NODUMP;
447 	if (fa.fsx_xflags & FS_XFLAG_NOATIME)
448 		binode->flags |= BTRFS_INODE_NOATIME;
449 	else
450 		binode->flags &= ~BTRFS_INODE_NOATIME;
451 
452 	/* 1 item for the inode */
453 	trans = btrfs_start_transaction(root, 1);
454 	if (IS_ERR(trans)) {
455 		ret = PTR_ERR(trans);
456 		goto out_unlock;
457 	}
458 
459 	btrfs_sync_inode_flags_to_i_flags(inode);
460 	inode_inc_iversion(inode);
461 	inode->i_ctime = current_time(inode);
462 	ret = btrfs_update_inode(trans, root, inode);
463 
464 	btrfs_end_transaction(trans);
465 
466 out_unlock:
467 	if (ret) {
468 		binode->flags = old_flags;
469 		inode->i_flags = old_i_flags;
470 	}
471 
472 	inode_unlock(inode);
473 	mnt_drop_write_file(file);
474 
475 	return ret;
476 }
477 
478 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
479 {
480 	struct inode *inode = file_inode(file);
481 
482 	return put_user(inode->i_generation, arg);
483 }
484 
485 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
486 {
487 	struct inode *inode = file_inode(file);
488 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
489 	struct btrfs_device *device;
490 	struct request_queue *q;
491 	struct fstrim_range range;
492 	u64 minlen = ULLONG_MAX;
493 	u64 num_devices = 0;
494 	u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
495 	int ret;
496 
497 	if (!capable(CAP_SYS_ADMIN))
498 		return -EPERM;
499 
500 	rcu_read_lock();
501 	list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
502 				dev_list) {
503 		if (!device->bdev)
504 			continue;
505 		q = bdev_get_queue(device->bdev);
506 		if (blk_queue_discard(q)) {
507 			num_devices++;
508 			minlen = min_t(u64, q->limits.discard_granularity,
509 				     minlen);
510 		}
511 	}
512 	rcu_read_unlock();
513 
514 	if (!num_devices)
515 		return -EOPNOTSUPP;
516 	if (copy_from_user(&range, arg, sizeof(range)))
517 		return -EFAULT;
518 	if (range.start > total_bytes ||
519 	    range.len < fs_info->sb->s_blocksize)
520 		return -EINVAL;
521 
522 	range.len = min(range.len, total_bytes - range.start);
523 	range.minlen = max(range.minlen, minlen);
524 	ret = btrfs_trim_fs(fs_info, &range);
525 	if (ret < 0)
526 		return ret;
527 
528 	if (copy_to_user(arg, &range, sizeof(range)))
529 		return -EFAULT;
530 
531 	return 0;
532 }
533 
534 int btrfs_is_empty_uuid(u8 *uuid)
535 {
536 	int i;
537 
538 	for (i = 0; i < BTRFS_UUID_SIZE; i++) {
539 		if (uuid[i])
540 			return 0;
541 	}
542 	return 1;
543 }
544 
545 static noinline int create_subvol(struct inode *dir,
546 				  struct dentry *dentry,
547 				  const char *name, int namelen,
548 				  u64 *async_transid,
549 				  struct btrfs_qgroup_inherit *inherit)
550 {
551 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
552 	struct btrfs_trans_handle *trans;
553 	struct btrfs_key key;
554 	struct btrfs_root_item *root_item;
555 	struct btrfs_inode_item *inode_item;
556 	struct extent_buffer *leaf;
557 	struct btrfs_root *root = BTRFS_I(dir)->root;
558 	struct btrfs_root *new_root;
559 	struct btrfs_block_rsv block_rsv;
560 	struct timespec64 cur_time = current_time(dir);
561 	struct inode *inode;
562 	int ret;
563 	int err;
564 	u64 objectid;
565 	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
566 	u64 index = 0;
567 	uuid_le new_uuid;
568 
569 	root_item = kzalloc(sizeof(*root_item), GFP_KERNEL);
570 	if (!root_item)
571 		return -ENOMEM;
572 
573 	ret = btrfs_find_free_objectid(fs_info->tree_root, &objectid);
574 	if (ret)
575 		goto fail_free;
576 
577 	/*
578 	 * Don't create subvolume whose level is not zero. Or qgroup will be
579 	 * screwed up since it assumes subvolume qgroup's level to be 0.
580 	 */
581 	if (btrfs_qgroup_level(objectid)) {
582 		ret = -ENOSPC;
583 		goto fail_free;
584 	}
585 
586 	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
587 	/*
588 	 * The same as the snapshot creation, please see the comment
589 	 * of create_snapshot().
590 	 */
591 	ret = btrfs_subvolume_reserve_metadata(root, &block_rsv, 8, false);
592 	if (ret)
593 		goto fail_free;
594 
595 	trans = btrfs_start_transaction(root, 0);
596 	if (IS_ERR(trans)) {
597 		ret = PTR_ERR(trans);
598 		btrfs_subvolume_release_metadata(fs_info, &block_rsv);
599 		goto fail_free;
600 	}
601 	trans->block_rsv = &block_rsv;
602 	trans->bytes_reserved = block_rsv.size;
603 
604 	ret = btrfs_qgroup_inherit(trans, 0, objectid, inherit);
605 	if (ret)
606 		goto fail;
607 
608 	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
609 	if (IS_ERR(leaf)) {
610 		ret = PTR_ERR(leaf);
611 		goto fail;
612 	}
613 
614 	btrfs_mark_buffer_dirty(leaf);
615 
616 	inode_item = &root_item->inode;
617 	btrfs_set_stack_inode_generation(inode_item, 1);
618 	btrfs_set_stack_inode_size(inode_item, 3);
619 	btrfs_set_stack_inode_nlink(inode_item, 1);
620 	btrfs_set_stack_inode_nbytes(inode_item,
621 				     fs_info->nodesize);
622 	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
623 
624 	btrfs_set_root_flags(root_item, 0);
625 	btrfs_set_root_limit(root_item, 0);
626 	btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
627 
628 	btrfs_set_root_bytenr(root_item, leaf->start);
629 	btrfs_set_root_generation(root_item, trans->transid);
630 	btrfs_set_root_level(root_item, 0);
631 	btrfs_set_root_refs(root_item, 1);
632 	btrfs_set_root_used(root_item, leaf->len);
633 	btrfs_set_root_last_snapshot(root_item, 0);
634 
635 	btrfs_set_root_generation_v2(root_item,
636 			btrfs_root_generation(root_item));
637 	uuid_le_gen(&new_uuid);
638 	memcpy(root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
639 	btrfs_set_stack_timespec_sec(&root_item->otime, cur_time.tv_sec);
640 	btrfs_set_stack_timespec_nsec(&root_item->otime, cur_time.tv_nsec);
641 	root_item->ctime = root_item->otime;
642 	btrfs_set_root_ctransid(root_item, trans->transid);
643 	btrfs_set_root_otransid(root_item, trans->transid);
644 
645 	btrfs_tree_unlock(leaf);
646 	free_extent_buffer(leaf);
647 	leaf = NULL;
648 
649 	btrfs_set_root_dirid(root_item, new_dirid);
650 
651 	key.objectid = objectid;
652 	key.offset = 0;
653 	key.type = BTRFS_ROOT_ITEM_KEY;
654 	ret = btrfs_insert_root(trans, fs_info->tree_root, &key,
655 				root_item);
656 	if (ret)
657 		goto fail;
658 
659 	key.offset = (u64)-1;
660 	new_root = btrfs_read_fs_root_no_name(fs_info, &key);
661 	if (IS_ERR(new_root)) {
662 		ret = PTR_ERR(new_root);
663 		btrfs_abort_transaction(trans, ret);
664 		goto fail;
665 	}
666 
667 	btrfs_record_root_in_trans(trans, new_root);
668 
669 	ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
670 	if (ret) {
671 		/* We potentially lose an unused inode item here */
672 		btrfs_abort_transaction(trans, ret);
673 		goto fail;
674 	}
675 
676 	mutex_lock(&new_root->objectid_mutex);
677 	new_root->highest_objectid = new_dirid;
678 	mutex_unlock(&new_root->objectid_mutex);
679 
680 	/*
681 	 * insert the directory item
682 	 */
683 	ret = btrfs_set_inode_index(BTRFS_I(dir), &index);
684 	if (ret) {
685 		btrfs_abort_transaction(trans, ret);
686 		goto fail;
687 	}
688 
689 	ret = btrfs_insert_dir_item(trans, root,
690 				    name, namelen, BTRFS_I(dir), &key,
691 				    BTRFS_FT_DIR, index);
692 	if (ret) {
693 		btrfs_abort_transaction(trans, ret);
694 		goto fail;
695 	}
696 
697 	btrfs_i_size_write(BTRFS_I(dir), dir->i_size + namelen * 2);
698 	ret = btrfs_update_inode(trans, root, dir);
699 	BUG_ON(ret);
700 
701 	ret = btrfs_add_root_ref(trans, objectid, root->root_key.objectid,
702 				 btrfs_ino(BTRFS_I(dir)), index, name, namelen);
703 	BUG_ON(ret);
704 
705 	ret = btrfs_uuid_tree_add(trans, root_item->uuid,
706 				  BTRFS_UUID_KEY_SUBVOL, objectid);
707 	if (ret)
708 		btrfs_abort_transaction(trans, ret);
709 
710 fail:
711 	kfree(root_item);
712 	trans->block_rsv = NULL;
713 	trans->bytes_reserved = 0;
714 	btrfs_subvolume_release_metadata(fs_info, &block_rsv);
715 
716 	if (async_transid) {
717 		*async_transid = trans->transid;
718 		err = btrfs_commit_transaction_async(trans, 1);
719 		if (err)
720 			err = btrfs_commit_transaction(trans);
721 	} else {
722 		err = btrfs_commit_transaction(trans);
723 	}
724 	if (err && !ret)
725 		ret = err;
726 
727 	if (!ret) {
728 		inode = btrfs_lookup_dentry(dir, dentry);
729 		if (IS_ERR(inode))
730 			return PTR_ERR(inode);
731 		d_instantiate(dentry, inode);
732 	}
733 	return ret;
734 
735 fail_free:
736 	kfree(root_item);
737 	return ret;
738 }
739 
740 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
741 			   struct dentry *dentry,
742 			   u64 *async_transid, bool readonly,
743 			   struct btrfs_qgroup_inherit *inherit)
744 {
745 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
746 	struct inode *inode;
747 	struct btrfs_pending_snapshot *pending_snapshot;
748 	struct btrfs_trans_handle *trans;
749 	int ret;
750 	bool snapshot_force_cow = false;
751 
752 	if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
753 		return -EINVAL;
754 
755 	pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
756 	if (!pending_snapshot)
757 		return -ENOMEM;
758 
759 	pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item),
760 			GFP_KERNEL);
761 	pending_snapshot->path = btrfs_alloc_path();
762 	if (!pending_snapshot->root_item || !pending_snapshot->path) {
763 		ret = -ENOMEM;
764 		goto free_pending;
765 	}
766 
767 	/*
768 	 * Force new buffered writes to reserve space even when NOCOW is
769 	 * possible. This is to avoid later writeback (running dealloc) to
770 	 * fallback to COW mode and unexpectedly fail with ENOSPC.
771 	 */
772 	atomic_inc(&root->will_be_snapshotted);
773 	smp_mb__after_atomic();
774 	/* wait for no snapshot writes */
775 	wait_event(root->subv_writers->wait,
776 		   percpu_counter_sum(&root->subv_writers->counter) == 0);
777 
778 	ret = btrfs_start_delalloc_inodes(root);
779 	if (ret)
780 		goto dec_and_free;
781 
782 	/*
783 	 * All previous writes have started writeback in NOCOW mode, so now
784 	 * we force future writes to fallback to COW mode during snapshot
785 	 * creation.
786 	 */
787 	atomic_inc(&root->snapshot_force_cow);
788 	snapshot_force_cow = true;
789 
790 	btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
791 
792 	btrfs_init_block_rsv(&pending_snapshot->block_rsv,
793 			     BTRFS_BLOCK_RSV_TEMP);
794 	/*
795 	 * 1 - parent dir inode
796 	 * 2 - dir entries
797 	 * 1 - root item
798 	 * 2 - root ref/backref
799 	 * 1 - root of snapshot
800 	 * 1 - UUID item
801 	 */
802 	ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
803 					&pending_snapshot->block_rsv, 8,
804 					false);
805 	if (ret)
806 		goto dec_and_free;
807 
808 	pending_snapshot->dentry = dentry;
809 	pending_snapshot->root = root;
810 	pending_snapshot->readonly = readonly;
811 	pending_snapshot->dir = dir;
812 	pending_snapshot->inherit = inherit;
813 
814 	trans = btrfs_start_transaction(root, 0);
815 	if (IS_ERR(trans)) {
816 		ret = PTR_ERR(trans);
817 		goto fail;
818 	}
819 
820 	spin_lock(&fs_info->trans_lock);
821 	list_add(&pending_snapshot->list,
822 		 &trans->transaction->pending_snapshots);
823 	spin_unlock(&fs_info->trans_lock);
824 	if (async_transid) {
825 		*async_transid = trans->transid;
826 		ret = btrfs_commit_transaction_async(trans, 1);
827 		if (ret)
828 			ret = btrfs_commit_transaction(trans);
829 	} else {
830 		ret = btrfs_commit_transaction(trans);
831 	}
832 	if (ret)
833 		goto fail;
834 
835 	ret = pending_snapshot->error;
836 	if (ret)
837 		goto fail;
838 
839 	ret = btrfs_orphan_cleanup(pending_snapshot->snap);
840 	if (ret)
841 		goto fail;
842 
843 	inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
844 	if (IS_ERR(inode)) {
845 		ret = PTR_ERR(inode);
846 		goto fail;
847 	}
848 
849 	d_instantiate(dentry, inode);
850 	ret = 0;
851 fail:
852 	btrfs_subvolume_release_metadata(fs_info, &pending_snapshot->block_rsv);
853 dec_and_free:
854 	if (snapshot_force_cow)
855 		atomic_dec(&root->snapshot_force_cow);
856 	if (atomic_dec_and_test(&root->will_be_snapshotted))
857 		wake_up_var(&root->will_be_snapshotted);
858 free_pending:
859 	kfree(pending_snapshot->root_item);
860 	btrfs_free_path(pending_snapshot->path);
861 	kfree(pending_snapshot);
862 
863 	return ret;
864 }
865 
866 /*  copy of may_delete in fs/namei.c()
867  *	Check whether we can remove a link victim from directory dir, check
868  *  whether the type of victim is right.
869  *  1. We can't do it if dir is read-only (done in permission())
870  *  2. We should have write and exec permissions on dir
871  *  3. We can't remove anything from append-only dir
872  *  4. We can't do anything with immutable dir (done in permission())
873  *  5. If the sticky bit on dir is set we should either
874  *	a. be owner of dir, or
875  *	b. be owner of victim, or
876  *	c. have CAP_FOWNER capability
877  *  6. If the victim is append-only or immutable we can't do anything with
878  *     links pointing to it.
879  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
880  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
881  *  9. We can't remove a root or mountpoint.
882  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
883  *     nfs_async_unlink().
884  */
885 
886 static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
887 {
888 	int error;
889 
890 	if (d_really_is_negative(victim))
891 		return -ENOENT;
892 
893 	BUG_ON(d_inode(victim->d_parent) != dir);
894 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
895 
896 	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
897 	if (error)
898 		return error;
899 	if (IS_APPEND(dir))
900 		return -EPERM;
901 	if (check_sticky(dir, d_inode(victim)) || IS_APPEND(d_inode(victim)) ||
902 	    IS_IMMUTABLE(d_inode(victim)) || IS_SWAPFILE(d_inode(victim)))
903 		return -EPERM;
904 	if (isdir) {
905 		if (!d_is_dir(victim))
906 			return -ENOTDIR;
907 		if (IS_ROOT(victim))
908 			return -EBUSY;
909 	} else if (d_is_dir(victim))
910 		return -EISDIR;
911 	if (IS_DEADDIR(dir))
912 		return -ENOENT;
913 	if (victim->d_flags & DCACHE_NFSFS_RENAMED)
914 		return -EBUSY;
915 	return 0;
916 }
917 
918 /* copy of may_create in fs/namei.c() */
919 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
920 {
921 	if (d_really_is_positive(child))
922 		return -EEXIST;
923 	if (IS_DEADDIR(dir))
924 		return -ENOENT;
925 	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
926 }
927 
928 /*
929  * Create a new subvolume below @parent.  This is largely modeled after
930  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
931  * inside this filesystem so it's quite a bit simpler.
932  */
933 static noinline int btrfs_mksubvol(const struct path *parent,
934 				   const char *name, int namelen,
935 				   struct btrfs_root *snap_src,
936 				   u64 *async_transid, bool readonly,
937 				   struct btrfs_qgroup_inherit *inherit)
938 {
939 	struct inode *dir = d_inode(parent->dentry);
940 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
941 	struct dentry *dentry;
942 	int error;
943 
944 	error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
945 	if (error == -EINTR)
946 		return error;
947 
948 	dentry = lookup_one_len(name, parent->dentry, namelen);
949 	error = PTR_ERR(dentry);
950 	if (IS_ERR(dentry))
951 		goto out_unlock;
952 
953 	error = btrfs_may_create(dir, dentry);
954 	if (error)
955 		goto out_dput;
956 
957 	/*
958 	 * even if this name doesn't exist, we may get hash collisions.
959 	 * check for them now when we can safely fail
960 	 */
961 	error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
962 					       dir->i_ino, name,
963 					       namelen);
964 	if (error)
965 		goto out_dput;
966 
967 	down_read(&fs_info->subvol_sem);
968 
969 	if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
970 		goto out_up_read;
971 
972 	if (snap_src) {
973 		error = create_snapshot(snap_src, dir, dentry,
974 					async_transid, readonly, inherit);
975 	} else {
976 		error = create_subvol(dir, dentry, name, namelen,
977 				      async_transid, inherit);
978 	}
979 	if (!error)
980 		fsnotify_mkdir(dir, dentry);
981 out_up_read:
982 	up_read(&fs_info->subvol_sem);
983 out_dput:
984 	dput(dentry);
985 out_unlock:
986 	inode_unlock(dir);
987 	return error;
988 }
989 
990 /*
991  * When we're defragging a range, we don't want to kick it off again
992  * if it is really just waiting for delalloc to send it down.
993  * If we find a nice big extent or delalloc range for the bytes in the
994  * file you want to defrag, we return 0 to let you know to skip this
995  * part of the file
996  */
997 static int check_defrag_in_cache(struct inode *inode, u64 offset, u32 thresh)
998 {
999 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1000 	struct extent_map *em = NULL;
1001 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1002 	u64 end;
1003 
1004 	read_lock(&em_tree->lock);
1005 	em = lookup_extent_mapping(em_tree, offset, PAGE_SIZE);
1006 	read_unlock(&em_tree->lock);
1007 
1008 	if (em) {
1009 		end = extent_map_end(em);
1010 		free_extent_map(em);
1011 		if (end - offset > thresh)
1012 			return 0;
1013 	}
1014 	/* if we already have a nice delalloc here, just stop */
1015 	thresh /= 2;
1016 	end = count_range_bits(io_tree, &offset, offset + thresh,
1017 			       thresh, EXTENT_DELALLOC, 1);
1018 	if (end >= thresh)
1019 		return 0;
1020 	return 1;
1021 }
1022 
1023 /*
1024  * helper function to walk through a file and find extents
1025  * newer than a specific transid, and smaller than thresh.
1026  *
1027  * This is used by the defragging code to find new and small
1028  * extents
1029  */
1030 static int find_new_extents(struct btrfs_root *root,
1031 			    struct inode *inode, u64 newer_than,
1032 			    u64 *off, u32 thresh)
1033 {
1034 	struct btrfs_path *path;
1035 	struct btrfs_key min_key;
1036 	struct extent_buffer *leaf;
1037 	struct btrfs_file_extent_item *extent;
1038 	int type;
1039 	int ret;
1040 	u64 ino = btrfs_ino(BTRFS_I(inode));
1041 
1042 	path = btrfs_alloc_path();
1043 	if (!path)
1044 		return -ENOMEM;
1045 
1046 	min_key.objectid = ino;
1047 	min_key.type = BTRFS_EXTENT_DATA_KEY;
1048 	min_key.offset = *off;
1049 
1050 	while (1) {
1051 		ret = btrfs_search_forward(root, &min_key, path, newer_than);
1052 		if (ret != 0)
1053 			goto none;
1054 process_slot:
1055 		if (min_key.objectid != ino)
1056 			goto none;
1057 		if (min_key.type != BTRFS_EXTENT_DATA_KEY)
1058 			goto none;
1059 
1060 		leaf = path->nodes[0];
1061 		extent = btrfs_item_ptr(leaf, path->slots[0],
1062 					struct btrfs_file_extent_item);
1063 
1064 		type = btrfs_file_extent_type(leaf, extent);
1065 		if (type == BTRFS_FILE_EXTENT_REG &&
1066 		    btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
1067 		    check_defrag_in_cache(inode, min_key.offset, thresh)) {
1068 			*off = min_key.offset;
1069 			btrfs_free_path(path);
1070 			return 0;
1071 		}
1072 
1073 		path->slots[0]++;
1074 		if (path->slots[0] < btrfs_header_nritems(leaf)) {
1075 			btrfs_item_key_to_cpu(leaf, &min_key, path->slots[0]);
1076 			goto process_slot;
1077 		}
1078 
1079 		if (min_key.offset == (u64)-1)
1080 			goto none;
1081 
1082 		min_key.offset++;
1083 		btrfs_release_path(path);
1084 	}
1085 none:
1086 	btrfs_free_path(path);
1087 	return -ENOENT;
1088 }
1089 
1090 static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start)
1091 {
1092 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1093 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1094 	struct extent_map *em;
1095 	u64 len = PAGE_SIZE;
1096 
1097 	/*
1098 	 * hopefully we have this extent in the tree already, try without
1099 	 * the full extent lock
1100 	 */
1101 	read_lock(&em_tree->lock);
1102 	em = lookup_extent_mapping(em_tree, start, len);
1103 	read_unlock(&em_tree->lock);
1104 
1105 	if (!em) {
1106 		struct extent_state *cached = NULL;
1107 		u64 end = start + len - 1;
1108 
1109 		/* get the big lock and read metadata off disk */
1110 		lock_extent_bits(io_tree, start, end, &cached);
1111 		em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
1112 		unlock_extent_cached(io_tree, start, end, &cached);
1113 
1114 		if (IS_ERR(em))
1115 			return NULL;
1116 	}
1117 
1118 	return em;
1119 }
1120 
1121 static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
1122 {
1123 	struct extent_map *next;
1124 	bool ret = true;
1125 
1126 	/* this is the last extent */
1127 	if (em->start + em->len >= i_size_read(inode))
1128 		return false;
1129 
1130 	next = defrag_lookup_extent(inode, em->start + em->len);
1131 	if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
1132 		ret = false;
1133 	else if ((em->block_start + em->block_len == next->block_start) &&
1134 		 (em->block_len > SZ_128K && next->block_len > SZ_128K))
1135 		ret = false;
1136 
1137 	free_extent_map(next);
1138 	return ret;
1139 }
1140 
1141 static int should_defrag_range(struct inode *inode, u64 start, u32 thresh,
1142 			       u64 *last_len, u64 *skip, u64 *defrag_end,
1143 			       int compress)
1144 {
1145 	struct extent_map *em;
1146 	int ret = 1;
1147 	bool next_mergeable = true;
1148 	bool prev_mergeable = true;
1149 
1150 	/*
1151 	 * make sure that once we start defragging an extent, we keep on
1152 	 * defragging it
1153 	 */
1154 	if (start < *defrag_end)
1155 		return 1;
1156 
1157 	*skip = 0;
1158 
1159 	em = defrag_lookup_extent(inode, start);
1160 	if (!em)
1161 		return 0;
1162 
1163 	/* this will cover holes, and inline extents */
1164 	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1165 		ret = 0;
1166 		goto out;
1167 	}
1168 
1169 	if (!*defrag_end)
1170 		prev_mergeable = false;
1171 
1172 	next_mergeable = defrag_check_next_extent(inode, em);
1173 	/*
1174 	 * we hit a real extent, if it is big or the next extent is not a
1175 	 * real extent, don't bother defragging it
1176 	 */
1177 	if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1178 	    (em->len >= thresh || (!next_mergeable && !prev_mergeable)))
1179 		ret = 0;
1180 out:
1181 	/*
1182 	 * last_len ends up being a counter of how many bytes we've defragged.
1183 	 * every time we choose not to defrag an extent, we reset *last_len
1184 	 * so that the next tiny extent will force a defrag.
1185 	 *
1186 	 * The end result of this is that tiny extents before a single big
1187 	 * extent will force at least part of that big extent to be defragged.
1188 	 */
1189 	if (ret) {
1190 		*defrag_end = extent_map_end(em);
1191 	} else {
1192 		*last_len = 0;
1193 		*skip = extent_map_end(em);
1194 		*defrag_end = 0;
1195 	}
1196 
1197 	free_extent_map(em);
1198 	return ret;
1199 }
1200 
1201 /*
1202  * it doesn't do much good to defrag one or two pages
1203  * at a time.  This pulls in a nice chunk of pages
1204  * to COW and defrag.
1205  *
1206  * It also makes sure the delalloc code has enough
1207  * dirty data to avoid making new small extents as part
1208  * of the defrag
1209  *
1210  * It's a good idea to start RA on this range
1211  * before calling this.
1212  */
1213 static int cluster_pages_for_defrag(struct inode *inode,
1214 				    struct page **pages,
1215 				    unsigned long start_index,
1216 				    unsigned long num_pages)
1217 {
1218 	unsigned long file_end;
1219 	u64 isize = i_size_read(inode);
1220 	u64 page_start;
1221 	u64 page_end;
1222 	u64 page_cnt;
1223 	int ret;
1224 	int i;
1225 	int i_done;
1226 	struct btrfs_ordered_extent *ordered;
1227 	struct extent_state *cached_state = NULL;
1228 	struct extent_io_tree *tree;
1229 	struct extent_changeset *data_reserved = NULL;
1230 	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1231 
1232 	file_end = (isize - 1) >> PAGE_SHIFT;
1233 	if (!isize || start_index > file_end)
1234 		return 0;
1235 
1236 	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1237 
1238 	ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
1239 			start_index << PAGE_SHIFT,
1240 			page_cnt << PAGE_SHIFT);
1241 	if (ret)
1242 		return ret;
1243 	i_done = 0;
1244 	tree = &BTRFS_I(inode)->io_tree;
1245 
1246 	/* step one, lock all the pages */
1247 	for (i = 0; i < page_cnt; i++) {
1248 		struct page *page;
1249 again:
1250 		page = find_or_create_page(inode->i_mapping,
1251 					   start_index + i, mask);
1252 		if (!page)
1253 			break;
1254 
1255 		page_start = page_offset(page);
1256 		page_end = page_start + PAGE_SIZE - 1;
1257 		while (1) {
1258 			lock_extent_bits(tree, page_start, page_end,
1259 					 &cached_state);
1260 			ordered = btrfs_lookup_ordered_extent(inode,
1261 							      page_start);
1262 			unlock_extent_cached(tree, page_start, page_end,
1263 					     &cached_state);
1264 			if (!ordered)
1265 				break;
1266 
1267 			unlock_page(page);
1268 			btrfs_start_ordered_extent(inode, ordered, 1);
1269 			btrfs_put_ordered_extent(ordered);
1270 			lock_page(page);
1271 			/*
1272 			 * we unlocked the page above, so we need check if
1273 			 * it was released or not.
1274 			 */
1275 			if (page->mapping != inode->i_mapping) {
1276 				unlock_page(page);
1277 				put_page(page);
1278 				goto again;
1279 			}
1280 		}
1281 
1282 		if (!PageUptodate(page)) {
1283 			btrfs_readpage(NULL, page);
1284 			lock_page(page);
1285 			if (!PageUptodate(page)) {
1286 				unlock_page(page);
1287 				put_page(page);
1288 				ret = -EIO;
1289 				break;
1290 			}
1291 		}
1292 
1293 		if (page->mapping != inode->i_mapping) {
1294 			unlock_page(page);
1295 			put_page(page);
1296 			goto again;
1297 		}
1298 
1299 		pages[i] = page;
1300 		i_done++;
1301 	}
1302 	if (!i_done || ret)
1303 		goto out;
1304 
1305 	if (!(inode->i_sb->s_flags & SB_ACTIVE))
1306 		goto out;
1307 
1308 	/*
1309 	 * so now we have a nice long stream of locked
1310 	 * and up to date pages, lets wait on them
1311 	 */
1312 	for (i = 0; i < i_done; i++)
1313 		wait_on_page_writeback(pages[i]);
1314 
1315 	page_start = page_offset(pages[0]);
1316 	page_end = page_offset(pages[i_done - 1]) + PAGE_SIZE;
1317 
1318 	lock_extent_bits(&BTRFS_I(inode)->io_tree,
1319 			 page_start, page_end - 1, &cached_state);
1320 	clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1321 			  page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1322 			  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1323 			  &cached_state);
1324 
1325 	if (i_done != page_cnt) {
1326 		spin_lock(&BTRFS_I(inode)->lock);
1327 		BTRFS_I(inode)->outstanding_extents++;
1328 		spin_unlock(&BTRFS_I(inode)->lock);
1329 		btrfs_delalloc_release_space(inode, data_reserved,
1330 				start_index << PAGE_SHIFT,
1331 				(page_cnt - i_done) << PAGE_SHIFT, true);
1332 	}
1333 
1334 
1335 	set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1336 			  &cached_state);
1337 
1338 	unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1339 			     page_start, page_end - 1, &cached_state);
1340 
1341 	for (i = 0; i < i_done; i++) {
1342 		clear_page_dirty_for_io(pages[i]);
1343 		ClearPageChecked(pages[i]);
1344 		set_page_extent_mapped(pages[i]);
1345 		set_page_dirty(pages[i]);
1346 		unlock_page(pages[i]);
1347 		put_page(pages[i]);
1348 	}
1349 	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT,
1350 				       false);
1351 	extent_changeset_free(data_reserved);
1352 	return i_done;
1353 out:
1354 	for (i = 0; i < i_done; i++) {
1355 		unlock_page(pages[i]);
1356 		put_page(pages[i]);
1357 	}
1358 	btrfs_delalloc_release_space(inode, data_reserved,
1359 			start_index << PAGE_SHIFT,
1360 			page_cnt << PAGE_SHIFT, true);
1361 	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT,
1362 				       true);
1363 	extent_changeset_free(data_reserved);
1364 	return ret;
1365 
1366 }
1367 
1368 int btrfs_defrag_file(struct inode *inode, struct file *file,
1369 		      struct btrfs_ioctl_defrag_range_args *range,
1370 		      u64 newer_than, unsigned long max_to_defrag)
1371 {
1372 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1373 	struct btrfs_root *root = BTRFS_I(inode)->root;
1374 	struct file_ra_state *ra = NULL;
1375 	unsigned long last_index;
1376 	u64 isize = i_size_read(inode);
1377 	u64 last_len = 0;
1378 	u64 skip = 0;
1379 	u64 defrag_end = 0;
1380 	u64 newer_off = range->start;
1381 	unsigned long i;
1382 	unsigned long ra_index = 0;
1383 	int ret;
1384 	int defrag_count = 0;
1385 	int compress_type = BTRFS_COMPRESS_ZLIB;
1386 	u32 extent_thresh = range->extent_thresh;
1387 	unsigned long max_cluster = SZ_256K >> PAGE_SHIFT;
1388 	unsigned long cluster = max_cluster;
1389 	u64 new_align = ~((u64)SZ_128K - 1);
1390 	struct page **pages = NULL;
1391 	bool do_compress = range->flags & BTRFS_DEFRAG_RANGE_COMPRESS;
1392 
1393 	if (isize == 0)
1394 		return 0;
1395 
1396 	if (range->start >= isize)
1397 		return -EINVAL;
1398 
1399 	if (do_compress) {
1400 		if (range->compress_type > BTRFS_COMPRESS_TYPES)
1401 			return -EINVAL;
1402 		if (range->compress_type)
1403 			compress_type = range->compress_type;
1404 	}
1405 
1406 	if (extent_thresh == 0)
1407 		extent_thresh = SZ_256K;
1408 
1409 	/*
1410 	 * If we were not given a file, allocate a readahead context. As
1411 	 * readahead is just an optimization, defrag will work without it so
1412 	 * we don't error out.
1413 	 */
1414 	if (!file) {
1415 		ra = kzalloc(sizeof(*ra), GFP_KERNEL);
1416 		if (ra)
1417 			file_ra_state_init(ra, inode->i_mapping);
1418 	} else {
1419 		ra = &file->f_ra;
1420 	}
1421 
1422 	pages = kmalloc_array(max_cluster, sizeof(struct page *), GFP_KERNEL);
1423 	if (!pages) {
1424 		ret = -ENOMEM;
1425 		goto out_ra;
1426 	}
1427 
1428 	/* find the last page to defrag */
1429 	if (range->start + range->len > range->start) {
1430 		last_index = min_t(u64, isize - 1,
1431 			 range->start + range->len - 1) >> PAGE_SHIFT;
1432 	} else {
1433 		last_index = (isize - 1) >> PAGE_SHIFT;
1434 	}
1435 
1436 	if (newer_than) {
1437 		ret = find_new_extents(root, inode, newer_than,
1438 				       &newer_off, SZ_64K);
1439 		if (!ret) {
1440 			range->start = newer_off;
1441 			/*
1442 			 * we always align our defrag to help keep
1443 			 * the extents in the file evenly spaced
1444 			 */
1445 			i = (newer_off & new_align) >> PAGE_SHIFT;
1446 		} else
1447 			goto out_ra;
1448 	} else {
1449 		i = range->start >> PAGE_SHIFT;
1450 	}
1451 	if (!max_to_defrag)
1452 		max_to_defrag = last_index - i + 1;
1453 
1454 	/*
1455 	 * make writeback starts from i, so the defrag range can be
1456 	 * written sequentially.
1457 	 */
1458 	if (i < inode->i_mapping->writeback_index)
1459 		inode->i_mapping->writeback_index = i;
1460 
1461 	while (i <= last_index && defrag_count < max_to_defrag &&
1462 	       (i < DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE))) {
1463 		/*
1464 		 * make sure we stop running if someone unmounts
1465 		 * the FS
1466 		 */
1467 		if (!(inode->i_sb->s_flags & SB_ACTIVE))
1468 			break;
1469 
1470 		if (btrfs_defrag_cancelled(fs_info)) {
1471 			btrfs_debug(fs_info, "defrag_file cancelled");
1472 			ret = -EAGAIN;
1473 			break;
1474 		}
1475 
1476 		if (!should_defrag_range(inode, (u64)i << PAGE_SHIFT,
1477 					 extent_thresh, &last_len, &skip,
1478 					 &defrag_end, do_compress)){
1479 			unsigned long next;
1480 			/*
1481 			 * the should_defrag function tells us how much to skip
1482 			 * bump our counter by the suggested amount
1483 			 */
1484 			next = DIV_ROUND_UP(skip, PAGE_SIZE);
1485 			i = max(i + 1, next);
1486 			continue;
1487 		}
1488 
1489 		if (!newer_than) {
1490 			cluster = (PAGE_ALIGN(defrag_end) >>
1491 				   PAGE_SHIFT) - i;
1492 			cluster = min(cluster, max_cluster);
1493 		} else {
1494 			cluster = max_cluster;
1495 		}
1496 
1497 		if (i + cluster > ra_index) {
1498 			ra_index = max(i, ra_index);
1499 			if (ra)
1500 				page_cache_sync_readahead(inode->i_mapping, ra,
1501 						file, ra_index, cluster);
1502 			ra_index += cluster;
1503 		}
1504 
1505 		inode_lock(inode);
1506 		if (do_compress)
1507 			BTRFS_I(inode)->defrag_compress = compress_type;
1508 		ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1509 		if (ret < 0) {
1510 			inode_unlock(inode);
1511 			goto out_ra;
1512 		}
1513 
1514 		defrag_count += ret;
1515 		balance_dirty_pages_ratelimited(inode->i_mapping);
1516 		inode_unlock(inode);
1517 
1518 		if (newer_than) {
1519 			if (newer_off == (u64)-1)
1520 				break;
1521 
1522 			if (ret > 0)
1523 				i += ret;
1524 
1525 			newer_off = max(newer_off + 1,
1526 					(u64)i << PAGE_SHIFT);
1527 
1528 			ret = find_new_extents(root, inode, newer_than,
1529 					       &newer_off, SZ_64K);
1530 			if (!ret) {
1531 				range->start = newer_off;
1532 				i = (newer_off & new_align) >> PAGE_SHIFT;
1533 			} else {
1534 				break;
1535 			}
1536 		} else {
1537 			if (ret > 0) {
1538 				i += ret;
1539 				last_len += ret << PAGE_SHIFT;
1540 			} else {
1541 				i++;
1542 				last_len = 0;
1543 			}
1544 		}
1545 	}
1546 
1547 	if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1548 		filemap_flush(inode->i_mapping);
1549 		if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1550 			     &BTRFS_I(inode)->runtime_flags))
1551 			filemap_flush(inode->i_mapping);
1552 	}
1553 
1554 	if (range->compress_type == BTRFS_COMPRESS_LZO) {
1555 		btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
1556 	} else if (range->compress_type == BTRFS_COMPRESS_ZSTD) {
1557 		btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
1558 	}
1559 
1560 	ret = defrag_count;
1561 
1562 out_ra:
1563 	if (do_compress) {
1564 		inode_lock(inode);
1565 		BTRFS_I(inode)->defrag_compress = BTRFS_COMPRESS_NONE;
1566 		inode_unlock(inode);
1567 	}
1568 	if (!file)
1569 		kfree(ra);
1570 	kfree(pages);
1571 	return ret;
1572 }
1573 
1574 static noinline int btrfs_ioctl_resize(struct file *file,
1575 					void __user *arg)
1576 {
1577 	struct inode *inode = file_inode(file);
1578 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1579 	u64 new_size;
1580 	u64 old_size;
1581 	u64 devid = 1;
1582 	struct btrfs_root *root = BTRFS_I(inode)->root;
1583 	struct btrfs_ioctl_vol_args *vol_args;
1584 	struct btrfs_trans_handle *trans;
1585 	struct btrfs_device *device = NULL;
1586 	char *sizestr;
1587 	char *retptr;
1588 	char *devstr = NULL;
1589 	int ret = 0;
1590 	int mod = 0;
1591 
1592 	if (!capable(CAP_SYS_ADMIN))
1593 		return -EPERM;
1594 
1595 	ret = mnt_want_write_file(file);
1596 	if (ret)
1597 		return ret;
1598 
1599 	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
1600 		mnt_drop_write_file(file);
1601 		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1602 	}
1603 
1604 	vol_args = memdup_user(arg, sizeof(*vol_args));
1605 	if (IS_ERR(vol_args)) {
1606 		ret = PTR_ERR(vol_args);
1607 		goto out;
1608 	}
1609 
1610 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1611 
1612 	sizestr = vol_args->name;
1613 	devstr = strchr(sizestr, ':');
1614 	if (devstr) {
1615 		sizestr = devstr + 1;
1616 		*devstr = '\0';
1617 		devstr = vol_args->name;
1618 		ret = kstrtoull(devstr, 10, &devid);
1619 		if (ret)
1620 			goto out_free;
1621 		if (!devid) {
1622 			ret = -EINVAL;
1623 			goto out_free;
1624 		}
1625 		btrfs_info(fs_info, "resizing devid %llu", devid);
1626 	}
1627 
1628 	device = btrfs_find_device(fs_info, devid, NULL, NULL);
1629 	if (!device) {
1630 		btrfs_info(fs_info, "resizer unable to find device %llu",
1631 			   devid);
1632 		ret = -ENODEV;
1633 		goto out_free;
1634 	}
1635 
1636 	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
1637 		btrfs_info(fs_info,
1638 			   "resizer unable to apply on readonly device %llu",
1639 		       devid);
1640 		ret = -EPERM;
1641 		goto out_free;
1642 	}
1643 
1644 	if (!strcmp(sizestr, "max"))
1645 		new_size = device->bdev->bd_inode->i_size;
1646 	else {
1647 		if (sizestr[0] == '-') {
1648 			mod = -1;
1649 			sizestr++;
1650 		} else if (sizestr[0] == '+') {
1651 			mod = 1;
1652 			sizestr++;
1653 		}
1654 		new_size = memparse(sizestr, &retptr);
1655 		if (*retptr != '\0' || new_size == 0) {
1656 			ret = -EINVAL;
1657 			goto out_free;
1658 		}
1659 	}
1660 
1661 	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
1662 		ret = -EPERM;
1663 		goto out_free;
1664 	}
1665 
1666 	old_size = btrfs_device_get_total_bytes(device);
1667 
1668 	if (mod < 0) {
1669 		if (new_size > old_size) {
1670 			ret = -EINVAL;
1671 			goto out_free;
1672 		}
1673 		new_size = old_size - new_size;
1674 	} else if (mod > 0) {
1675 		if (new_size > ULLONG_MAX - old_size) {
1676 			ret = -ERANGE;
1677 			goto out_free;
1678 		}
1679 		new_size = old_size + new_size;
1680 	}
1681 
1682 	if (new_size < SZ_256M) {
1683 		ret = -EINVAL;
1684 		goto out_free;
1685 	}
1686 	if (new_size > device->bdev->bd_inode->i_size) {
1687 		ret = -EFBIG;
1688 		goto out_free;
1689 	}
1690 
1691 	new_size = round_down(new_size, fs_info->sectorsize);
1692 
1693 	btrfs_info_in_rcu(fs_info, "new size for %s is %llu",
1694 			  rcu_str_deref(device->name), new_size);
1695 
1696 	if (new_size > old_size) {
1697 		trans = btrfs_start_transaction(root, 0);
1698 		if (IS_ERR(trans)) {
1699 			ret = PTR_ERR(trans);
1700 			goto out_free;
1701 		}
1702 		ret = btrfs_grow_device(trans, device, new_size);
1703 		btrfs_commit_transaction(trans);
1704 	} else if (new_size < old_size) {
1705 		ret = btrfs_shrink_device(device, new_size);
1706 	} /* equal, nothing need to do */
1707 
1708 out_free:
1709 	kfree(vol_args);
1710 out:
1711 	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
1712 	mnt_drop_write_file(file);
1713 	return ret;
1714 }
1715 
1716 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1717 				const char *name, unsigned long fd, int subvol,
1718 				u64 *transid, bool readonly,
1719 				struct btrfs_qgroup_inherit *inherit)
1720 {
1721 	int namelen;
1722 	int ret = 0;
1723 
1724 	if (!S_ISDIR(file_inode(file)->i_mode))
1725 		return -ENOTDIR;
1726 
1727 	ret = mnt_want_write_file(file);
1728 	if (ret)
1729 		goto out;
1730 
1731 	namelen = strlen(name);
1732 	if (strchr(name, '/')) {
1733 		ret = -EINVAL;
1734 		goto out_drop_write;
1735 	}
1736 
1737 	if (name[0] == '.' &&
1738 	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1739 		ret = -EEXIST;
1740 		goto out_drop_write;
1741 	}
1742 
1743 	if (subvol) {
1744 		ret = btrfs_mksubvol(&file->f_path, name, namelen,
1745 				     NULL, transid, readonly, inherit);
1746 	} else {
1747 		struct fd src = fdget(fd);
1748 		struct inode *src_inode;
1749 		if (!src.file) {
1750 			ret = -EINVAL;
1751 			goto out_drop_write;
1752 		}
1753 
1754 		src_inode = file_inode(src.file);
1755 		if (src_inode->i_sb != file_inode(file)->i_sb) {
1756 			btrfs_info(BTRFS_I(file_inode(file))->root->fs_info,
1757 				   "Snapshot src from another FS");
1758 			ret = -EXDEV;
1759 		} else if (!inode_owner_or_capable(src_inode)) {
1760 			/*
1761 			 * Subvolume creation is not restricted, but snapshots
1762 			 * are limited to own subvolumes only
1763 			 */
1764 			ret = -EPERM;
1765 		} else {
1766 			ret = btrfs_mksubvol(&file->f_path, name, namelen,
1767 					     BTRFS_I(src_inode)->root,
1768 					     transid, readonly, inherit);
1769 		}
1770 		fdput(src);
1771 	}
1772 out_drop_write:
1773 	mnt_drop_write_file(file);
1774 out:
1775 	return ret;
1776 }
1777 
1778 static noinline int btrfs_ioctl_snap_create(struct file *file,
1779 					    void __user *arg, int subvol)
1780 {
1781 	struct btrfs_ioctl_vol_args *vol_args;
1782 	int ret;
1783 
1784 	if (!S_ISDIR(file_inode(file)->i_mode))
1785 		return -ENOTDIR;
1786 
1787 	vol_args = memdup_user(arg, sizeof(*vol_args));
1788 	if (IS_ERR(vol_args))
1789 		return PTR_ERR(vol_args);
1790 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1791 
1792 	ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1793 					      vol_args->fd, subvol,
1794 					      NULL, false, NULL);
1795 
1796 	kfree(vol_args);
1797 	return ret;
1798 }
1799 
1800 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1801 					       void __user *arg, int subvol)
1802 {
1803 	struct btrfs_ioctl_vol_args_v2 *vol_args;
1804 	int ret;
1805 	u64 transid = 0;
1806 	u64 *ptr = NULL;
1807 	bool readonly = false;
1808 	struct btrfs_qgroup_inherit *inherit = NULL;
1809 
1810 	if (!S_ISDIR(file_inode(file)->i_mode))
1811 		return -ENOTDIR;
1812 
1813 	vol_args = memdup_user(arg, sizeof(*vol_args));
1814 	if (IS_ERR(vol_args))
1815 		return PTR_ERR(vol_args);
1816 	vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1817 
1818 	if (vol_args->flags &
1819 	    ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
1820 	      BTRFS_SUBVOL_QGROUP_INHERIT)) {
1821 		ret = -EOPNOTSUPP;
1822 		goto free_args;
1823 	}
1824 
1825 	if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
1826 		ptr = &transid;
1827 	if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1828 		readonly = true;
1829 	if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1830 		if (vol_args->size > PAGE_SIZE) {
1831 			ret = -EINVAL;
1832 			goto free_args;
1833 		}
1834 		inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1835 		if (IS_ERR(inherit)) {
1836 			ret = PTR_ERR(inherit);
1837 			goto free_args;
1838 		}
1839 	}
1840 
1841 	ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1842 					      vol_args->fd, subvol, ptr,
1843 					      readonly, inherit);
1844 	if (ret)
1845 		goto free_inherit;
1846 
1847 	if (ptr && copy_to_user(arg +
1848 				offsetof(struct btrfs_ioctl_vol_args_v2,
1849 					transid),
1850 				ptr, sizeof(*ptr)))
1851 		ret = -EFAULT;
1852 
1853 free_inherit:
1854 	kfree(inherit);
1855 free_args:
1856 	kfree(vol_args);
1857 	return ret;
1858 }
1859 
1860 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1861 						void __user *arg)
1862 {
1863 	struct inode *inode = file_inode(file);
1864 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1865 	struct btrfs_root *root = BTRFS_I(inode)->root;
1866 	int ret = 0;
1867 	u64 flags = 0;
1868 
1869 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID)
1870 		return -EINVAL;
1871 
1872 	down_read(&fs_info->subvol_sem);
1873 	if (btrfs_root_readonly(root))
1874 		flags |= BTRFS_SUBVOL_RDONLY;
1875 	up_read(&fs_info->subvol_sem);
1876 
1877 	if (copy_to_user(arg, &flags, sizeof(flags)))
1878 		ret = -EFAULT;
1879 
1880 	return ret;
1881 }
1882 
1883 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1884 					      void __user *arg)
1885 {
1886 	struct inode *inode = file_inode(file);
1887 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1888 	struct btrfs_root *root = BTRFS_I(inode)->root;
1889 	struct btrfs_trans_handle *trans;
1890 	u64 root_flags;
1891 	u64 flags;
1892 	int ret = 0;
1893 
1894 	if (!inode_owner_or_capable(inode))
1895 		return -EPERM;
1896 
1897 	ret = mnt_want_write_file(file);
1898 	if (ret)
1899 		goto out;
1900 
1901 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1902 		ret = -EINVAL;
1903 		goto out_drop_write;
1904 	}
1905 
1906 	if (copy_from_user(&flags, arg, sizeof(flags))) {
1907 		ret = -EFAULT;
1908 		goto out_drop_write;
1909 	}
1910 
1911 	if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1912 		ret = -EINVAL;
1913 		goto out_drop_write;
1914 	}
1915 
1916 	if (flags & ~BTRFS_SUBVOL_RDONLY) {
1917 		ret = -EOPNOTSUPP;
1918 		goto out_drop_write;
1919 	}
1920 
1921 	down_write(&fs_info->subvol_sem);
1922 
1923 	/* nothing to do */
1924 	if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1925 		goto out_drop_sem;
1926 
1927 	root_flags = btrfs_root_flags(&root->root_item);
1928 	if (flags & BTRFS_SUBVOL_RDONLY) {
1929 		btrfs_set_root_flags(&root->root_item,
1930 				     root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1931 	} else {
1932 		/*
1933 		 * Block RO -> RW transition if this subvolume is involved in
1934 		 * send
1935 		 */
1936 		spin_lock(&root->root_item_lock);
1937 		if (root->send_in_progress == 0) {
1938 			btrfs_set_root_flags(&root->root_item,
1939 				     root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1940 			spin_unlock(&root->root_item_lock);
1941 		} else {
1942 			spin_unlock(&root->root_item_lock);
1943 			btrfs_warn(fs_info,
1944 				   "Attempt to set subvolume %llu read-write during send",
1945 				   root->root_key.objectid);
1946 			ret = -EPERM;
1947 			goto out_drop_sem;
1948 		}
1949 	}
1950 
1951 	trans = btrfs_start_transaction(root, 1);
1952 	if (IS_ERR(trans)) {
1953 		ret = PTR_ERR(trans);
1954 		goto out_reset;
1955 	}
1956 
1957 	ret = btrfs_update_root(trans, fs_info->tree_root,
1958 				&root->root_key, &root->root_item);
1959 	if (ret < 0) {
1960 		btrfs_end_transaction(trans);
1961 		goto out_reset;
1962 	}
1963 
1964 	ret = btrfs_commit_transaction(trans);
1965 
1966 out_reset:
1967 	if (ret)
1968 		btrfs_set_root_flags(&root->root_item, root_flags);
1969 out_drop_sem:
1970 	up_write(&fs_info->subvol_sem);
1971 out_drop_write:
1972 	mnt_drop_write_file(file);
1973 out:
1974 	return ret;
1975 }
1976 
1977 static noinline int key_in_sk(struct btrfs_key *key,
1978 			      struct btrfs_ioctl_search_key *sk)
1979 {
1980 	struct btrfs_key test;
1981 	int ret;
1982 
1983 	test.objectid = sk->min_objectid;
1984 	test.type = sk->min_type;
1985 	test.offset = sk->min_offset;
1986 
1987 	ret = btrfs_comp_cpu_keys(key, &test);
1988 	if (ret < 0)
1989 		return 0;
1990 
1991 	test.objectid = sk->max_objectid;
1992 	test.type = sk->max_type;
1993 	test.offset = sk->max_offset;
1994 
1995 	ret = btrfs_comp_cpu_keys(key, &test);
1996 	if (ret > 0)
1997 		return 0;
1998 	return 1;
1999 }
2000 
2001 static noinline int copy_to_sk(struct btrfs_path *path,
2002 			       struct btrfs_key *key,
2003 			       struct btrfs_ioctl_search_key *sk,
2004 			       size_t *buf_size,
2005 			       char __user *ubuf,
2006 			       unsigned long *sk_offset,
2007 			       int *num_found)
2008 {
2009 	u64 found_transid;
2010 	struct extent_buffer *leaf;
2011 	struct btrfs_ioctl_search_header sh;
2012 	struct btrfs_key test;
2013 	unsigned long item_off;
2014 	unsigned long item_len;
2015 	int nritems;
2016 	int i;
2017 	int slot;
2018 	int ret = 0;
2019 
2020 	leaf = path->nodes[0];
2021 	slot = path->slots[0];
2022 	nritems = btrfs_header_nritems(leaf);
2023 
2024 	if (btrfs_header_generation(leaf) > sk->max_transid) {
2025 		i = nritems;
2026 		goto advance_key;
2027 	}
2028 	found_transid = btrfs_header_generation(leaf);
2029 
2030 	for (i = slot; i < nritems; i++) {
2031 		item_off = btrfs_item_ptr_offset(leaf, i);
2032 		item_len = btrfs_item_size_nr(leaf, i);
2033 
2034 		btrfs_item_key_to_cpu(leaf, key, i);
2035 		if (!key_in_sk(key, sk))
2036 			continue;
2037 
2038 		if (sizeof(sh) + item_len > *buf_size) {
2039 			if (*num_found) {
2040 				ret = 1;
2041 				goto out;
2042 			}
2043 
2044 			/*
2045 			 * return one empty item back for v1, which does not
2046 			 * handle -EOVERFLOW
2047 			 */
2048 
2049 			*buf_size = sizeof(sh) + item_len;
2050 			item_len = 0;
2051 			ret = -EOVERFLOW;
2052 		}
2053 
2054 		if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
2055 			ret = 1;
2056 			goto out;
2057 		}
2058 
2059 		sh.objectid = key->objectid;
2060 		sh.offset = key->offset;
2061 		sh.type = key->type;
2062 		sh.len = item_len;
2063 		sh.transid = found_transid;
2064 
2065 		/* copy search result header */
2066 		if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
2067 			ret = -EFAULT;
2068 			goto out;
2069 		}
2070 
2071 		*sk_offset += sizeof(sh);
2072 
2073 		if (item_len) {
2074 			char __user *up = ubuf + *sk_offset;
2075 			/* copy the item */
2076 			if (read_extent_buffer_to_user(leaf, up,
2077 						       item_off, item_len)) {
2078 				ret = -EFAULT;
2079 				goto out;
2080 			}
2081 
2082 			*sk_offset += item_len;
2083 		}
2084 		(*num_found)++;
2085 
2086 		if (ret) /* -EOVERFLOW from above */
2087 			goto out;
2088 
2089 		if (*num_found >= sk->nr_items) {
2090 			ret = 1;
2091 			goto out;
2092 		}
2093 	}
2094 advance_key:
2095 	ret = 0;
2096 	test.objectid = sk->max_objectid;
2097 	test.type = sk->max_type;
2098 	test.offset = sk->max_offset;
2099 	if (btrfs_comp_cpu_keys(key, &test) >= 0)
2100 		ret = 1;
2101 	else if (key->offset < (u64)-1)
2102 		key->offset++;
2103 	else if (key->type < (u8)-1) {
2104 		key->offset = 0;
2105 		key->type++;
2106 	} else if (key->objectid < (u64)-1) {
2107 		key->offset = 0;
2108 		key->type = 0;
2109 		key->objectid++;
2110 	} else
2111 		ret = 1;
2112 out:
2113 	/*
2114 	 *  0: all items from this leaf copied, continue with next
2115 	 *  1: * more items can be copied, but unused buffer is too small
2116 	 *     * all items were found
2117 	 *     Either way, it will stops the loop which iterates to the next
2118 	 *     leaf
2119 	 *  -EOVERFLOW: item was to large for buffer
2120 	 *  -EFAULT: could not copy extent buffer back to userspace
2121 	 */
2122 	return ret;
2123 }
2124 
2125 static noinline int search_ioctl(struct inode *inode,
2126 				 struct btrfs_ioctl_search_key *sk,
2127 				 size_t *buf_size,
2128 				 char __user *ubuf)
2129 {
2130 	struct btrfs_fs_info *info = btrfs_sb(inode->i_sb);
2131 	struct btrfs_root *root;
2132 	struct btrfs_key key;
2133 	struct btrfs_path *path;
2134 	int ret;
2135 	int num_found = 0;
2136 	unsigned long sk_offset = 0;
2137 
2138 	if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
2139 		*buf_size = sizeof(struct btrfs_ioctl_search_header);
2140 		return -EOVERFLOW;
2141 	}
2142 
2143 	path = btrfs_alloc_path();
2144 	if (!path)
2145 		return -ENOMEM;
2146 
2147 	if (sk->tree_id == 0) {
2148 		/* search the root of the inode that was passed */
2149 		root = BTRFS_I(inode)->root;
2150 	} else {
2151 		key.objectid = sk->tree_id;
2152 		key.type = BTRFS_ROOT_ITEM_KEY;
2153 		key.offset = (u64)-1;
2154 		root = btrfs_read_fs_root_no_name(info, &key);
2155 		if (IS_ERR(root)) {
2156 			btrfs_free_path(path);
2157 			return PTR_ERR(root);
2158 		}
2159 	}
2160 
2161 	key.objectid = sk->min_objectid;
2162 	key.type = sk->min_type;
2163 	key.offset = sk->min_offset;
2164 
2165 	while (1) {
2166 		ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2167 		if (ret != 0) {
2168 			if (ret > 0)
2169 				ret = 0;
2170 			goto err;
2171 		}
2172 		ret = copy_to_sk(path, &key, sk, buf_size, ubuf,
2173 				 &sk_offset, &num_found);
2174 		btrfs_release_path(path);
2175 		if (ret)
2176 			break;
2177 
2178 	}
2179 	if (ret > 0)
2180 		ret = 0;
2181 err:
2182 	sk->nr_items = num_found;
2183 	btrfs_free_path(path);
2184 	return ret;
2185 }
2186 
2187 static noinline int btrfs_ioctl_tree_search(struct file *file,
2188 					   void __user *argp)
2189 {
2190 	struct btrfs_ioctl_search_args __user *uargs;
2191 	struct btrfs_ioctl_search_key sk;
2192 	struct inode *inode;
2193 	int ret;
2194 	size_t buf_size;
2195 
2196 	if (!capable(CAP_SYS_ADMIN))
2197 		return -EPERM;
2198 
2199 	uargs = (struct btrfs_ioctl_search_args __user *)argp;
2200 
2201 	if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
2202 		return -EFAULT;
2203 
2204 	buf_size = sizeof(uargs->buf);
2205 
2206 	inode = file_inode(file);
2207 	ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
2208 
2209 	/*
2210 	 * In the origin implementation an overflow is handled by returning a
2211 	 * search header with a len of zero, so reset ret.
2212 	 */
2213 	if (ret == -EOVERFLOW)
2214 		ret = 0;
2215 
2216 	if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
2217 		ret = -EFAULT;
2218 	return ret;
2219 }
2220 
2221 static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
2222 					       void __user *argp)
2223 {
2224 	struct btrfs_ioctl_search_args_v2 __user *uarg;
2225 	struct btrfs_ioctl_search_args_v2 args;
2226 	struct inode *inode;
2227 	int ret;
2228 	size_t buf_size;
2229 	const size_t buf_limit = SZ_16M;
2230 
2231 	if (!capable(CAP_SYS_ADMIN))
2232 		return -EPERM;
2233 
2234 	/* copy search header and buffer size */
2235 	uarg = (struct btrfs_ioctl_search_args_v2 __user *)argp;
2236 	if (copy_from_user(&args, uarg, sizeof(args)))
2237 		return -EFAULT;
2238 
2239 	buf_size = args.buf_size;
2240 
2241 	/* limit result size to 16MB */
2242 	if (buf_size > buf_limit)
2243 		buf_size = buf_limit;
2244 
2245 	inode = file_inode(file);
2246 	ret = search_ioctl(inode, &args.key, &buf_size,
2247 			   (char __user *)(&uarg->buf[0]));
2248 	if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
2249 		ret = -EFAULT;
2250 	else if (ret == -EOVERFLOW &&
2251 		copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
2252 		ret = -EFAULT;
2253 
2254 	return ret;
2255 }
2256 
2257 /*
2258  * Search INODE_REFs to identify path name of 'dirid' directory
2259  * in a 'tree_id' tree. and sets path name to 'name'.
2260  */
2261 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2262 				u64 tree_id, u64 dirid, char *name)
2263 {
2264 	struct btrfs_root *root;
2265 	struct btrfs_key key;
2266 	char *ptr;
2267 	int ret = -1;
2268 	int slot;
2269 	int len;
2270 	int total_len = 0;
2271 	struct btrfs_inode_ref *iref;
2272 	struct extent_buffer *l;
2273 	struct btrfs_path *path;
2274 
2275 	if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2276 		name[0]='\0';
2277 		return 0;
2278 	}
2279 
2280 	path = btrfs_alloc_path();
2281 	if (!path)
2282 		return -ENOMEM;
2283 
2284 	ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX - 1];
2285 
2286 	key.objectid = tree_id;
2287 	key.type = BTRFS_ROOT_ITEM_KEY;
2288 	key.offset = (u64)-1;
2289 	root = btrfs_read_fs_root_no_name(info, &key);
2290 	if (IS_ERR(root)) {
2291 		ret = PTR_ERR(root);
2292 		goto out;
2293 	}
2294 
2295 	key.objectid = dirid;
2296 	key.type = BTRFS_INODE_REF_KEY;
2297 	key.offset = (u64)-1;
2298 
2299 	while (1) {
2300 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2301 		if (ret < 0)
2302 			goto out;
2303 		else if (ret > 0) {
2304 			ret = btrfs_previous_item(root, path, dirid,
2305 						  BTRFS_INODE_REF_KEY);
2306 			if (ret < 0)
2307 				goto out;
2308 			else if (ret > 0) {
2309 				ret = -ENOENT;
2310 				goto out;
2311 			}
2312 		}
2313 
2314 		l = path->nodes[0];
2315 		slot = path->slots[0];
2316 		btrfs_item_key_to_cpu(l, &key, slot);
2317 
2318 		iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2319 		len = btrfs_inode_ref_name_len(l, iref);
2320 		ptr -= len + 1;
2321 		total_len += len + 1;
2322 		if (ptr < name) {
2323 			ret = -ENAMETOOLONG;
2324 			goto out;
2325 		}
2326 
2327 		*(ptr + len) = '/';
2328 		read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2329 
2330 		if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2331 			break;
2332 
2333 		btrfs_release_path(path);
2334 		key.objectid = key.offset;
2335 		key.offset = (u64)-1;
2336 		dirid = key.objectid;
2337 	}
2338 	memmove(name, ptr, total_len);
2339 	name[total_len] = '\0';
2340 	ret = 0;
2341 out:
2342 	btrfs_free_path(path);
2343 	return ret;
2344 }
2345 
2346 static int btrfs_search_path_in_tree_user(struct inode *inode,
2347 				struct btrfs_ioctl_ino_lookup_user_args *args)
2348 {
2349 	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2350 	struct super_block *sb = inode->i_sb;
2351 	struct btrfs_key upper_limit = BTRFS_I(inode)->location;
2352 	u64 treeid = BTRFS_I(inode)->root->root_key.objectid;
2353 	u64 dirid = args->dirid;
2354 	unsigned long item_off;
2355 	unsigned long item_len;
2356 	struct btrfs_inode_ref *iref;
2357 	struct btrfs_root_ref *rref;
2358 	struct btrfs_root *root;
2359 	struct btrfs_path *path;
2360 	struct btrfs_key key, key2;
2361 	struct extent_buffer *leaf;
2362 	struct inode *temp_inode;
2363 	char *ptr;
2364 	int slot;
2365 	int len;
2366 	int total_len = 0;
2367 	int ret;
2368 
2369 	path = btrfs_alloc_path();
2370 	if (!path)
2371 		return -ENOMEM;
2372 
2373 	/*
2374 	 * If the bottom subvolume does not exist directly under upper_limit,
2375 	 * construct the path in from the bottom up.
2376 	 */
2377 	if (dirid != upper_limit.objectid) {
2378 		ptr = &args->path[BTRFS_INO_LOOKUP_USER_PATH_MAX - 1];
2379 
2380 		key.objectid = treeid;
2381 		key.type = BTRFS_ROOT_ITEM_KEY;
2382 		key.offset = (u64)-1;
2383 		root = btrfs_read_fs_root_no_name(fs_info, &key);
2384 		if (IS_ERR(root)) {
2385 			ret = PTR_ERR(root);
2386 			goto out;
2387 		}
2388 
2389 		key.objectid = dirid;
2390 		key.type = BTRFS_INODE_REF_KEY;
2391 		key.offset = (u64)-1;
2392 		while (1) {
2393 			ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2394 			if (ret < 0) {
2395 				goto out;
2396 			} else if (ret > 0) {
2397 				ret = btrfs_previous_item(root, path, dirid,
2398 							  BTRFS_INODE_REF_KEY);
2399 				if (ret < 0) {
2400 					goto out;
2401 				} else if (ret > 0) {
2402 					ret = -ENOENT;
2403 					goto out;
2404 				}
2405 			}
2406 
2407 			leaf = path->nodes[0];
2408 			slot = path->slots[0];
2409 			btrfs_item_key_to_cpu(leaf, &key, slot);
2410 
2411 			iref = btrfs_item_ptr(leaf, slot, struct btrfs_inode_ref);
2412 			len = btrfs_inode_ref_name_len(leaf, iref);
2413 			ptr -= len + 1;
2414 			total_len += len + 1;
2415 			if (ptr < args->path) {
2416 				ret = -ENAMETOOLONG;
2417 				goto out;
2418 			}
2419 
2420 			*(ptr + len) = '/';
2421 			read_extent_buffer(leaf, ptr,
2422 					(unsigned long)(iref + 1), len);
2423 
2424 			/* Check the read+exec permission of this directory */
2425 			ret = btrfs_previous_item(root, path, dirid,
2426 						  BTRFS_INODE_ITEM_KEY);
2427 			if (ret < 0) {
2428 				goto out;
2429 			} else if (ret > 0) {
2430 				ret = -ENOENT;
2431 				goto out;
2432 			}
2433 
2434 			leaf = path->nodes[0];
2435 			slot = path->slots[0];
2436 			btrfs_item_key_to_cpu(leaf, &key2, slot);
2437 			if (key2.objectid != dirid) {
2438 				ret = -ENOENT;
2439 				goto out;
2440 			}
2441 
2442 			temp_inode = btrfs_iget(sb, &key2, root, NULL);
2443 			if (IS_ERR(temp_inode)) {
2444 				ret = PTR_ERR(temp_inode);
2445 				goto out;
2446 			}
2447 			ret = inode_permission(temp_inode, MAY_READ | MAY_EXEC);
2448 			iput(temp_inode);
2449 			if (ret) {
2450 				ret = -EACCES;
2451 				goto out;
2452 			}
2453 
2454 			if (key.offset == upper_limit.objectid)
2455 				break;
2456 			if (key.objectid == BTRFS_FIRST_FREE_OBJECTID) {
2457 				ret = -EACCES;
2458 				goto out;
2459 			}
2460 
2461 			btrfs_release_path(path);
2462 			key.objectid = key.offset;
2463 			key.offset = (u64)-1;
2464 			dirid = key.objectid;
2465 		}
2466 
2467 		memmove(args->path, ptr, total_len);
2468 		args->path[total_len] = '\0';
2469 		btrfs_release_path(path);
2470 	}
2471 
2472 	/* Get the bottom subvolume's name from ROOT_REF */
2473 	root = fs_info->tree_root;
2474 	key.objectid = treeid;
2475 	key.type = BTRFS_ROOT_REF_KEY;
2476 	key.offset = args->treeid;
2477 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2478 	if (ret < 0) {
2479 		goto out;
2480 	} else if (ret > 0) {
2481 		ret = -ENOENT;
2482 		goto out;
2483 	}
2484 
2485 	leaf = path->nodes[0];
2486 	slot = path->slots[0];
2487 	btrfs_item_key_to_cpu(leaf, &key, slot);
2488 
2489 	item_off = btrfs_item_ptr_offset(leaf, slot);
2490 	item_len = btrfs_item_size_nr(leaf, slot);
2491 	/* Check if dirid in ROOT_REF corresponds to passed dirid */
2492 	rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2493 	if (args->dirid != btrfs_root_ref_dirid(leaf, rref)) {
2494 		ret = -EINVAL;
2495 		goto out;
2496 	}
2497 
2498 	/* Copy subvolume's name */
2499 	item_off += sizeof(struct btrfs_root_ref);
2500 	item_len -= sizeof(struct btrfs_root_ref);
2501 	read_extent_buffer(leaf, args->name, item_off, item_len);
2502 	args->name[item_len] = 0;
2503 
2504 out:
2505 	btrfs_free_path(path);
2506 	return ret;
2507 }
2508 
2509 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2510 					   void __user *argp)
2511 {
2512 	struct btrfs_ioctl_ino_lookup_args *args;
2513 	struct inode *inode;
2514 	int ret = 0;
2515 
2516 	args = memdup_user(argp, sizeof(*args));
2517 	if (IS_ERR(args))
2518 		return PTR_ERR(args);
2519 
2520 	inode = file_inode(file);
2521 
2522 	/*
2523 	 * Unprivileged query to obtain the containing subvolume root id. The
2524 	 * path is reset so it's consistent with btrfs_search_path_in_tree.
2525 	 */
2526 	if (args->treeid == 0)
2527 		args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2528 
2529 	if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2530 		args->name[0] = 0;
2531 		goto out;
2532 	}
2533 
2534 	if (!capable(CAP_SYS_ADMIN)) {
2535 		ret = -EPERM;
2536 		goto out;
2537 	}
2538 
2539 	ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2540 					args->treeid, args->objectid,
2541 					args->name);
2542 
2543 out:
2544 	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2545 		ret = -EFAULT;
2546 
2547 	kfree(args);
2548 	return ret;
2549 }
2550 
2551 /*
2552  * Version of ino_lookup ioctl (unprivileged)
2553  *
2554  * The main differences from ino_lookup ioctl are:
2555  *
2556  *   1. Read + Exec permission will be checked using inode_permission() during
2557  *      path construction. -EACCES will be returned in case of failure.
2558  *   2. Path construction will be stopped at the inode number which corresponds
2559  *      to the fd with which this ioctl is called. If constructed path does not
2560  *      exist under fd's inode, -EACCES will be returned.
2561  *   3. The name of bottom subvolume is also searched and filled.
2562  */
2563 static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp)
2564 {
2565 	struct btrfs_ioctl_ino_lookup_user_args *args;
2566 	struct inode *inode;
2567 	int ret;
2568 
2569 	args = memdup_user(argp, sizeof(*args));
2570 	if (IS_ERR(args))
2571 		return PTR_ERR(args);
2572 
2573 	inode = file_inode(file);
2574 
2575 	if (args->dirid == BTRFS_FIRST_FREE_OBJECTID &&
2576 	    BTRFS_I(inode)->location.objectid != BTRFS_FIRST_FREE_OBJECTID) {
2577 		/*
2578 		 * The subvolume does not exist under fd with which this is
2579 		 * called
2580 		 */
2581 		kfree(args);
2582 		return -EACCES;
2583 	}
2584 
2585 	ret = btrfs_search_path_in_tree_user(inode, args);
2586 
2587 	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2588 		ret = -EFAULT;
2589 
2590 	kfree(args);
2591 	return ret;
2592 }
2593 
2594 /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */
2595 static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
2596 {
2597 	struct btrfs_ioctl_get_subvol_info_args *subvol_info;
2598 	struct btrfs_fs_info *fs_info;
2599 	struct btrfs_root *root;
2600 	struct btrfs_path *path;
2601 	struct btrfs_key key;
2602 	struct btrfs_root_item *root_item;
2603 	struct btrfs_root_ref *rref;
2604 	struct extent_buffer *leaf;
2605 	unsigned long item_off;
2606 	unsigned long item_len;
2607 	struct inode *inode;
2608 	int slot;
2609 	int ret = 0;
2610 
2611 	path = btrfs_alloc_path();
2612 	if (!path)
2613 		return -ENOMEM;
2614 
2615 	subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL);
2616 	if (!subvol_info) {
2617 		btrfs_free_path(path);
2618 		return -ENOMEM;
2619 	}
2620 
2621 	inode = file_inode(file);
2622 	fs_info = BTRFS_I(inode)->root->fs_info;
2623 
2624 	/* Get root_item of inode's subvolume */
2625 	key.objectid = BTRFS_I(inode)->root->root_key.objectid;
2626 	key.type = BTRFS_ROOT_ITEM_KEY;
2627 	key.offset = (u64)-1;
2628 	root = btrfs_read_fs_root_no_name(fs_info, &key);
2629 	if (IS_ERR(root)) {
2630 		ret = PTR_ERR(root);
2631 		goto out;
2632 	}
2633 	root_item = &root->root_item;
2634 
2635 	subvol_info->treeid = key.objectid;
2636 
2637 	subvol_info->generation = btrfs_root_generation(root_item);
2638 	subvol_info->flags = btrfs_root_flags(root_item);
2639 
2640 	memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE);
2641 	memcpy(subvol_info->parent_uuid, root_item->parent_uuid,
2642 						    BTRFS_UUID_SIZE);
2643 	memcpy(subvol_info->received_uuid, root_item->received_uuid,
2644 						    BTRFS_UUID_SIZE);
2645 
2646 	subvol_info->ctransid = btrfs_root_ctransid(root_item);
2647 	subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
2648 	subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
2649 
2650 	subvol_info->otransid = btrfs_root_otransid(root_item);
2651 	subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
2652 	subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
2653 
2654 	subvol_info->stransid = btrfs_root_stransid(root_item);
2655 	subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
2656 	subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
2657 
2658 	subvol_info->rtransid = btrfs_root_rtransid(root_item);
2659 	subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
2660 	subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
2661 
2662 	if (key.objectid != BTRFS_FS_TREE_OBJECTID) {
2663 		/* Search root tree for ROOT_BACKREF of this subvolume */
2664 		root = fs_info->tree_root;
2665 
2666 		key.type = BTRFS_ROOT_BACKREF_KEY;
2667 		key.offset = 0;
2668 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2669 		if (ret < 0) {
2670 			goto out;
2671 		} else if (path->slots[0] >=
2672 			   btrfs_header_nritems(path->nodes[0])) {
2673 			ret = btrfs_next_leaf(root, path);
2674 			if (ret < 0) {
2675 				goto out;
2676 			} else if (ret > 0) {
2677 				ret = -EUCLEAN;
2678 				goto out;
2679 			}
2680 		}
2681 
2682 		leaf = path->nodes[0];
2683 		slot = path->slots[0];
2684 		btrfs_item_key_to_cpu(leaf, &key, slot);
2685 		if (key.objectid == subvol_info->treeid &&
2686 		    key.type == BTRFS_ROOT_BACKREF_KEY) {
2687 			subvol_info->parent_id = key.offset;
2688 
2689 			rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2690 			subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref);
2691 
2692 			item_off = btrfs_item_ptr_offset(leaf, slot)
2693 					+ sizeof(struct btrfs_root_ref);
2694 			item_len = btrfs_item_size_nr(leaf, slot)
2695 					- sizeof(struct btrfs_root_ref);
2696 			read_extent_buffer(leaf, subvol_info->name,
2697 					   item_off, item_len);
2698 		} else {
2699 			ret = -ENOENT;
2700 			goto out;
2701 		}
2702 	}
2703 
2704 	if (copy_to_user(argp, subvol_info, sizeof(*subvol_info)))
2705 		ret = -EFAULT;
2706 
2707 out:
2708 	btrfs_free_path(path);
2709 	kzfree(subvol_info);
2710 	return ret;
2711 }
2712 
2713 /*
2714  * Return ROOT_REF information of the subvolume containing this inode
2715  * except the subvolume name.
2716  */
2717 static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
2718 {
2719 	struct btrfs_ioctl_get_subvol_rootref_args *rootrefs;
2720 	struct btrfs_root_ref *rref;
2721 	struct btrfs_root *root;
2722 	struct btrfs_path *path;
2723 	struct btrfs_key key;
2724 	struct extent_buffer *leaf;
2725 	struct inode *inode;
2726 	u64 objectid;
2727 	int slot;
2728 	int ret;
2729 	u8 found;
2730 
2731 	path = btrfs_alloc_path();
2732 	if (!path)
2733 		return -ENOMEM;
2734 
2735 	rootrefs = memdup_user(argp, sizeof(*rootrefs));
2736 	if (IS_ERR(rootrefs)) {
2737 		btrfs_free_path(path);
2738 		return PTR_ERR(rootrefs);
2739 	}
2740 
2741 	inode = file_inode(file);
2742 	root = BTRFS_I(inode)->root->fs_info->tree_root;
2743 	objectid = BTRFS_I(inode)->root->root_key.objectid;
2744 
2745 	key.objectid = objectid;
2746 	key.type = BTRFS_ROOT_REF_KEY;
2747 	key.offset = rootrefs->min_treeid;
2748 	found = 0;
2749 
2750 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2751 	if (ret < 0) {
2752 		goto out;
2753 	} else if (path->slots[0] >=
2754 		   btrfs_header_nritems(path->nodes[0])) {
2755 		ret = btrfs_next_leaf(root, path);
2756 		if (ret < 0) {
2757 			goto out;
2758 		} else if (ret > 0) {
2759 			ret = -EUCLEAN;
2760 			goto out;
2761 		}
2762 	}
2763 	while (1) {
2764 		leaf = path->nodes[0];
2765 		slot = path->slots[0];
2766 
2767 		btrfs_item_key_to_cpu(leaf, &key, slot);
2768 		if (key.objectid != objectid || key.type != BTRFS_ROOT_REF_KEY) {
2769 			ret = 0;
2770 			goto out;
2771 		}
2772 
2773 		if (found == BTRFS_MAX_ROOTREF_BUFFER_NUM) {
2774 			ret = -EOVERFLOW;
2775 			goto out;
2776 		}
2777 
2778 		rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2779 		rootrefs->rootref[found].treeid = key.offset;
2780 		rootrefs->rootref[found].dirid =
2781 				  btrfs_root_ref_dirid(leaf, rref);
2782 		found++;
2783 
2784 		ret = btrfs_next_item(root, path);
2785 		if (ret < 0) {
2786 			goto out;
2787 		} else if (ret > 0) {
2788 			ret = -EUCLEAN;
2789 			goto out;
2790 		}
2791 	}
2792 
2793 out:
2794 	if (!ret || ret == -EOVERFLOW) {
2795 		rootrefs->num_items = found;
2796 		/* update min_treeid for next search */
2797 		if (found)
2798 			rootrefs->min_treeid =
2799 				rootrefs->rootref[found - 1].treeid + 1;
2800 		if (copy_to_user(argp, rootrefs, sizeof(*rootrefs)))
2801 			ret = -EFAULT;
2802 	}
2803 
2804 	kfree(rootrefs);
2805 	btrfs_free_path(path);
2806 
2807 	return ret;
2808 }
2809 
2810 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2811 					     void __user *arg)
2812 {
2813 	struct dentry *parent = file->f_path.dentry;
2814 	struct btrfs_fs_info *fs_info = btrfs_sb(parent->d_sb);
2815 	struct dentry *dentry;
2816 	struct inode *dir = d_inode(parent);
2817 	struct inode *inode;
2818 	struct btrfs_root *root = BTRFS_I(dir)->root;
2819 	struct btrfs_root *dest = NULL;
2820 	struct btrfs_ioctl_vol_args *vol_args;
2821 	int namelen;
2822 	int err = 0;
2823 
2824 	if (!S_ISDIR(dir->i_mode))
2825 		return -ENOTDIR;
2826 
2827 	vol_args = memdup_user(arg, sizeof(*vol_args));
2828 	if (IS_ERR(vol_args))
2829 		return PTR_ERR(vol_args);
2830 
2831 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2832 	namelen = strlen(vol_args->name);
2833 	if (strchr(vol_args->name, '/') ||
2834 	    strncmp(vol_args->name, "..", namelen) == 0) {
2835 		err = -EINVAL;
2836 		goto out;
2837 	}
2838 
2839 	err = mnt_want_write_file(file);
2840 	if (err)
2841 		goto out;
2842 
2843 
2844 	err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
2845 	if (err == -EINTR)
2846 		goto out_drop_write;
2847 	dentry = lookup_one_len(vol_args->name, parent, namelen);
2848 	if (IS_ERR(dentry)) {
2849 		err = PTR_ERR(dentry);
2850 		goto out_unlock_dir;
2851 	}
2852 
2853 	if (d_really_is_negative(dentry)) {
2854 		err = -ENOENT;
2855 		goto out_dput;
2856 	}
2857 
2858 	inode = d_inode(dentry);
2859 	dest = BTRFS_I(inode)->root;
2860 	if (!capable(CAP_SYS_ADMIN)) {
2861 		/*
2862 		 * Regular user.  Only allow this with a special mount
2863 		 * option, when the user has write+exec access to the
2864 		 * subvol root, and when rmdir(2) would have been
2865 		 * allowed.
2866 		 *
2867 		 * Note that this is _not_ check that the subvol is
2868 		 * empty or doesn't contain data that we wouldn't
2869 		 * otherwise be able to delete.
2870 		 *
2871 		 * Users who want to delete empty subvols should try
2872 		 * rmdir(2).
2873 		 */
2874 		err = -EPERM;
2875 		if (!btrfs_test_opt(fs_info, USER_SUBVOL_RM_ALLOWED))
2876 			goto out_dput;
2877 
2878 		/*
2879 		 * Do not allow deletion if the parent dir is the same
2880 		 * as the dir to be deleted.  That means the ioctl
2881 		 * must be called on the dentry referencing the root
2882 		 * of the subvol, not a random directory contained
2883 		 * within it.
2884 		 */
2885 		err = -EINVAL;
2886 		if (root == dest)
2887 			goto out_dput;
2888 
2889 		err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2890 		if (err)
2891 			goto out_dput;
2892 	}
2893 
2894 	/* check if subvolume may be deleted by a user */
2895 	err = btrfs_may_delete(dir, dentry, 1);
2896 	if (err)
2897 		goto out_dput;
2898 
2899 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2900 		err = -EINVAL;
2901 		goto out_dput;
2902 	}
2903 
2904 	inode_lock(inode);
2905 	err = btrfs_delete_subvolume(dir, dentry);
2906 	inode_unlock(inode);
2907 	if (!err)
2908 		d_delete(dentry);
2909 
2910 out_dput:
2911 	dput(dentry);
2912 out_unlock_dir:
2913 	inode_unlock(dir);
2914 out_drop_write:
2915 	mnt_drop_write_file(file);
2916 out:
2917 	kfree(vol_args);
2918 	return err;
2919 }
2920 
2921 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2922 {
2923 	struct inode *inode = file_inode(file);
2924 	struct btrfs_root *root = BTRFS_I(inode)->root;
2925 	struct btrfs_ioctl_defrag_range_args *range;
2926 	int ret;
2927 
2928 	ret = mnt_want_write_file(file);
2929 	if (ret)
2930 		return ret;
2931 
2932 	if (btrfs_root_readonly(root)) {
2933 		ret = -EROFS;
2934 		goto out;
2935 	}
2936 
2937 	switch (inode->i_mode & S_IFMT) {
2938 	case S_IFDIR:
2939 		if (!capable(CAP_SYS_ADMIN)) {
2940 			ret = -EPERM;
2941 			goto out;
2942 		}
2943 		ret = btrfs_defrag_root(root);
2944 		break;
2945 	case S_IFREG:
2946 		/*
2947 		 * Note that this does not check the file descriptor for write
2948 		 * access. This prevents defragmenting executables that are
2949 		 * running and allows defrag on files open in read-only mode.
2950 		 */
2951 		if (!capable(CAP_SYS_ADMIN) &&
2952 		    inode_permission(inode, MAY_WRITE)) {
2953 			ret = -EPERM;
2954 			goto out;
2955 		}
2956 
2957 		range = kzalloc(sizeof(*range), GFP_KERNEL);
2958 		if (!range) {
2959 			ret = -ENOMEM;
2960 			goto out;
2961 		}
2962 
2963 		if (argp) {
2964 			if (copy_from_user(range, argp,
2965 					   sizeof(*range))) {
2966 				ret = -EFAULT;
2967 				kfree(range);
2968 				goto out;
2969 			}
2970 			/* compression requires us to start the IO */
2971 			if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2972 				range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
2973 				range->extent_thresh = (u32)-1;
2974 			}
2975 		} else {
2976 			/* the rest are all set to zero by kzalloc */
2977 			range->len = (u64)-1;
2978 		}
2979 		ret = btrfs_defrag_file(file_inode(file), file,
2980 					range, BTRFS_OLDEST_GENERATION, 0);
2981 		if (ret > 0)
2982 			ret = 0;
2983 		kfree(range);
2984 		break;
2985 	default:
2986 		ret = -EINVAL;
2987 	}
2988 out:
2989 	mnt_drop_write_file(file);
2990 	return ret;
2991 }
2992 
2993 static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
2994 {
2995 	struct btrfs_ioctl_vol_args *vol_args;
2996 	int ret;
2997 
2998 	if (!capable(CAP_SYS_ADMIN))
2999 		return -EPERM;
3000 
3001 	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags))
3002 		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3003 
3004 	vol_args = memdup_user(arg, sizeof(*vol_args));
3005 	if (IS_ERR(vol_args)) {
3006 		ret = PTR_ERR(vol_args);
3007 		goto out;
3008 	}
3009 
3010 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
3011 	ret = btrfs_init_new_device(fs_info, vol_args->name);
3012 
3013 	if (!ret)
3014 		btrfs_info(fs_info, "disk added %s", vol_args->name);
3015 
3016 	kfree(vol_args);
3017 out:
3018 	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3019 	return ret;
3020 }
3021 
3022 static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
3023 {
3024 	struct inode *inode = file_inode(file);
3025 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3026 	struct btrfs_ioctl_vol_args_v2 *vol_args;
3027 	int ret;
3028 
3029 	if (!capable(CAP_SYS_ADMIN))
3030 		return -EPERM;
3031 
3032 	ret = mnt_want_write_file(file);
3033 	if (ret)
3034 		return ret;
3035 
3036 	vol_args = memdup_user(arg, sizeof(*vol_args));
3037 	if (IS_ERR(vol_args)) {
3038 		ret = PTR_ERR(vol_args);
3039 		goto err_drop;
3040 	}
3041 
3042 	/* Check for compatibility reject unknown flags */
3043 	if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED) {
3044 		ret = -EOPNOTSUPP;
3045 		goto out;
3046 	}
3047 
3048 	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3049 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3050 		goto out;
3051 	}
3052 
3053 	if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
3054 		ret = btrfs_rm_device(fs_info, NULL, vol_args->devid);
3055 	} else {
3056 		vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
3057 		ret = btrfs_rm_device(fs_info, vol_args->name, 0);
3058 	}
3059 	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3060 
3061 	if (!ret) {
3062 		if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
3063 			btrfs_info(fs_info, "device deleted: id %llu",
3064 					vol_args->devid);
3065 		else
3066 			btrfs_info(fs_info, "device deleted: %s",
3067 					vol_args->name);
3068 	}
3069 out:
3070 	kfree(vol_args);
3071 err_drop:
3072 	mnt_drop_write_file(file);
3073 	return ret;
3074 }
3075 
3076 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
3077 {
3078 	struct inode *inode = file_inode(file);
3079 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3080 	struct btrfs_ioctl_vol_args *vol_args;
3081 	int ret;
3082 
3083 	if (!capable(CAP_SYS_ADMIN))
3084 		return -EPERM;
3085 
3086 	ret = mnt_want_write_file(file);
3087 	if (ret)
3088 		return ret;
3089 
3090 	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3091 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3092 		goto out_drop_write;
3093 	}
3094 
3095 	vol_args = memdup_user(arg, sizeof(*vol_args));
3096 	if (IS_ERR(vol_args)) {
3097 		ret = PTR_ERR(vol_args);
3098 		goto out;
3099 	}
3100 
3101 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
3102 	ret = btrfs_rm_device(fs_info, vol_args->name, 0);
3103 
3104 	if (!ret)
3105 		btrfs_info(fs_info, "disk deleted %s", vol_args->name);
3106 	kfree(vol_args);
3107 out:
3108 	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3109 out_drop_write:
3110 	mnt_drop_write_file(file);
3111 
3112 	return ret;
3113 }
3114 
3115 static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info,
3116 				void __user *arg)
3117 {
3118 	struct btrfs_ioctl_fs_info_args *fi_args;
3119 	struct btrfs_device *device;
3120 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
3121 	int ret = 0;
3122 
3123 	fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
3124 	if (!fi_args)
3125 		return -ENOMEM;
3126 
3127 	rcu_read_lock();
3128 	fi_args->num_devices = fs_devices->num_devices;
3129 
3130 	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
3131 		if (device->devid > fi_args->max_id)
3132 			fi_args->max_id = device->devid;
3133 	}
3134 	rcu_read_unlock();
3135 
3136 	memcpy(&fi_args->fsid, fs_info->fsid, sizeof(fi_args->fsid));
3137 	fi_args->nodesize = fs_info->nodesize;
3138 	fi_args->sectorsize = fs_info->sectorsize;
3139 	fi_args->clone_alignment = fs_info->sectorsize;
3140 
3141 	if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
3142 		ret = -EFAULT;
3143 
3144 	kfree(fi_args);
3145 	return ret;
3146 }
3147 
3148 static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
3149 				 void __user *arg)
3150 {
3151 	struct btrfs_ioctl_dev_info_args *di_args;
3152 	struct btrfs_device *dev;
3153 	int ret = 0;
3154 	char *s_uuid = NULL;
3155 
3156 	di_args = memdup_user(arg, sizeof(*di_args));
3157 	if (IS_ERR(di_args))
3158 		return PTR_ERR(di_args);
3159 
3160 	if (!btrfs_is_empty_uuid(di_args->uuid))
3161 		s_uuid = di_args->uuid;
3162 
3163 	rcu_read_lock();
3164 	dev = btrfs_find_device(fs_info, di_args->devid, s_uuid, NULL);
3165 
3166 	if (!dev) {
3167 		ret = -ENODEV;
3168 		goto out;
3169 	}
3170 
3171 	di_args->devid = dev->devid;
3172 	di_args->bytes_used = btrfs_device_get_bytes_used(dev);
3173 	di_args->total_bytes = btrfs_device_get_total_bytes(dev);
3174 	memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
3175 	if (dev->name) {
3176 		strncpy(di_args->path, rcu_str_deref(dev->name),
3177 				sizeof(di_args->path) - 1);
3178 		di_args->path[sizeof(di_args->path) - 1] = 0;
3179 	} else {
3180 		di_args->path[0] = '\0';
3181 	}
3182 
3183 out:
3184 	rcu_read_unlock();
3185 	if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
3186 		ret = -EFAULT;
3187 
3188 	kfree(di_args);
3189 	return ret;
3190 }
3191 
3192 static struct page *extent_same_get_page(struct inode *inode, pgoff_t index)
3193 {
3194 	struct page *page;
3195 
3196 	page = grab_cache_page(inode->i_mapping, index);
3197 	if (!page)
3198 		return ERR_PTR(-ENOMEM);
3199 
3200 	if (!PageUptodate(page)) {
3201 		int ret;
3202 
3203 		ret = btrfs_readpage(NULL, page);
3204 		if (ret)
3205 			return ERR_PTR(ret);
3206 		lock_page(page);
3207 		if (!PageUptodate(page)) {
3208 			unlock_page(page);
3209 			put_page(page);
3210 			return ERR_PTR(-EIO);
3211 		}
3212 		if (page->mapping != inode->i_mapping) {
3213 			unlock_page(page);
3214 			put_page(page);
3215 			return ERR_PTR(-EAGAIN);
3216 		}
3217 	}
3218 
3219 	return page;
3220 }
3221 
3222 static int gather_extent_pages(struct inode *inode, struct page **pages,
3223 			       int num_pages, u64 off)
3224 {
3225 	int i;
3226 	pgoff_t index = off >> PAGE_SHIFT;
3227 
3228 	for (i = 0; i < num_pages; i++) {
3229 again:
3230 		pages[i] = extent_same_get_page(inode, index + i);
3231 		if (IS_ERR(pages[i])) {
3232 			int err = PTR_ERR(pages[i]);
3233 
3234 			if (err == -EAGAIN)
3235 				goto again;
3236 			pages[i] = NULL;
3237 			return err;
3238 		}
3239 	}
3240 	return 0;
3241 }
3242 
3243 static int lock_extent_range(struct inode *inode, u64 off, u64 len,
3244 			     bool retry_range_locking)
3245 {
3246 	/*
3247 	 * Do any pending delalloc/csum calculations on inode, one way or
3248 	 * another, and lock file content.
3249 	 * The locking order is:
3250 	 *
3251 	 *   1) pages
3252 	 *   2) range in the inode's io tree
3253 	 */
3254 	while (1) {
3255 		struct btrfs_ordered_extent *ordered;
3256 		lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
3257 		ordered = btrfs_lookup_first_ordered_extent(inode,
3258 							    off + len - 1);
3259 		if ((!ordered ||
3260 		     ordered->file_offset + ordered->len <= off ||
3261 		     ordered->file_offset >= off + len) &&
3262 		    !test_range_bit(&BTRFS_I(inode)->io_tree, off,
3263 				    off + len - 1, EXTENT_DELALLOC, 0, NULL)) {
3264 			if (ordered)
3265 				btrfs_put_ordered_extent(ordered);
3266 			break;
3267 		}
3268 		unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
3269 		if (ordered)
3270 			btrfs_put_ordered_extent(ordered);
3271 		if (!retry_range_locking)
3272 			return -EAGAIN;
3273 		btrfs_wait_ordered_range(inode, off, len);
3274 	}
3275 	return 0;
3276 }
3277 
3278 static void btrfs_double_inode_unlock(struct inode *inode1, struct inode *inode2)
3279 {
3280 	inode_unlock(inode1);
3281 	inode_unlock(inode2);
3282 }
3283 
3284 static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
3285 {
3286 	if (inode1 < inode2)
3287 		swap(inode1, inode2);
3288 
3289 	inode_lock_nested(inode1, I_MUTEX_PARENT);
3290 	inode_lock_nested(inode2, I_MUTEX_CHILD);
3291 }
3292 
3293 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
3294 				      struct inode *inode2, u64 loff2, u64 len)
3295 {
3296 	unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
3297 	unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
3298 }
3299 
3300 static int btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
3301 				    struct inode *inode2, u64 loff2, u64 len,
3302 				    bool retry_range_locking)
3303 {
3304 	int ret;
3305 
3306 	if (inode1 < inode2) {
3307 		swap(inode1, inode2);
3308 		swap(loff1, loff2);
3309 	}
3310 	ret = lock_extent_range(inode1, loff1, len, retry_range_locking);
3311 	if (ret)
3312 		return ret;
3313 	ret = lock_extent_range(inode2, loff2, len, retry_range_locking);
3314 	if (ret)
3315 		unlock_extent(&BTRFS_I(inode1)->io_tree, loff1,
3316 			      loff1 + len - 1);
3317 	return ret;
3318 }
3319 
3320 struct cmp_pages {
3321 	int		num_pages;
3322 	struct page	**src_pages;
3323 	struct page	**dst_pages;
3324 };
3325 
3326 static void btrfs_cmp_data_free(struct cmp_pages *cmp)
3327 {
3328 	int i;
3329 	struct page *pg;
3330 
3331 	for (i = 0; i < cmp->num_pages; i++) {
3332 		pg = cmp->src_pages[i];
3333 		if (pg) {
3334 			unlock_page(pg);
3335 			put_page(pg);
3336 			cmp->src_pages[i] = NULL;
3337 		}
3338 		pg = cmp->dst_pages[i];
3339 		if (pg) {
3340 			unlock_page(pg);
3341 			put_page(pg);
3342 			cmp->dst_pages[i] = NULL;
3343 		}
3344 	}
3345 }
3346 
3347 static int btrfs_cmp_data_prepare(struct inode *src, u64 loff,
3348 				  struct inode *dst, u64 dst_loff,
3349 				  u64 len, struct cmp_pages *cmp)
3350 {
3351 	int ret;
3352 	int num_pages = PAGE_ALIGN(len) >> PAGE_SHIFT;
3353 
3354 	cmp->num_pages = num_pages;
3355 
3356 	ret = gather_extent_pages(src, cmp->src_pages, num_pages, loff);
3357 	if (ret)
3358 		goto out;
3359 
3360 	ret = gather_extent_pages(dst, cmp->dst_pages, num_pages, dst_loff);
3361 
3362 out:
3363 	if (ret)
3364 		btrfs_cmp_data_free(cmp);
3365 	return ret;
3366 }
3367 
3368 static int btrfs_cmp_data(u64 len, struct cmp_pages *cmp)
3369 {
3370 	int ret = 0;
3371 	int i;
3372 	struct page *src_page, *dst_page;
3373 	unsigned int cmp_len = PAGE_SIZE;
3374 	void *addr, *dst_addr;
3375 
3376 	i = 0;
3377 	while (len) {
3378 		if (len < PAGE_SIZE)
3379 			cmp_len = len;
3380 
3381 		BUG_ON(i >= cmp->num_pages);
3382 
3383 		src_page = cmp->src_pages[i];
3384 		dst_page = cmp->dst_pages[i];
3385 		ASSERT(PageLocked(src_page));
3386 		ASSERT(PageLocked(dst_page));
3387 
3388 		addr = kmap_atomic(src_page);
3389 		dst_addr = kmap_atomic(dst_page);
3390 
3391 		flush_dcache_page(src_page);
3392 		flush_dcache_page(dst_page);
3393 
3394 		if (memcmp(addr, dst_addr, cmp_len))
3395 			ret = -EBADE;
3396 
3397 		kunmap_atomic(addr);
3398 		kunmap_atomic(dst_addr);
3399 
3400 		if (ret)
3401 			break;
3402 
3403 		len -= cmp_len;
3404 		i++;
3405 	}
3406 
3407 	return ret;
3408 }
3409 
3410 static int extent_same_check_offsets(struct inode *inode, u64 off, u64 *plen,
3411 				     u64 olen)
3412 {
3413 	u64 len = *plen;
3414 	u64 bs = BTRFS_I(inode)->root->fs_info->sb->s_blocksize;
3415 
3416 	if (off + olen > inode->i_size || off + olen < off)
3417 		return -EINVAL;
3418 
3419 	/* if we extend to eof, continue to block boundary */
3420 	if (off + len == inode->i_size)
3421 		*plen = len = ALIGN(inode->i_size, bs) - off;
3422 
3423 	/* Check that we are block aligned - btrfs_clone() requires this */
3424 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs))
3425 		return -EINVAL;
3426 
3427 	return 0;
3428 }
3429 
3430 static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 olen,
3431 				   struct inode *dst, u64 dst_loff,
3432 				   struct cmp_pages *cmp)
3433 {
3434 	int ret;
3435 	u64 len = olen;
3436 	bool same_inode = (src == dst);
3437 	u64 same_lock_start = 0;
3438 	u64 same_lock_len = 0;
3439 
3440 	ret = extent_same_check_offsets(src, loff, &len, olen);
3441 	if (ret)
3442 		return ret;
3443 
3444 	ret = extent_same_check_offsets(dst, dst_loff, &len, olen);
3445 	if (ret)
3446 		return ret;
3447 
3448 	if (same_inode) {
3449 		/*
3450 		 * Single inode case wants the same checks, except we
3451 		 * don't want our length pushed out past i_size as
3452 		 * comparing that data range makes no sense.
3453 		 *
3454 		 * extent_same_check_offsets() will do this for an
3455 		 * unaligned length at i_size, so catch it here and
3456 		 * reject the request.
3457 		 *
3458 		 * This effectively means we require aligned extents
3459 		 * for the single-inode case, whereas the other cases
3460 		 * allow an unaligned length so long as it ends at
3461 		 * i_size.
3462 		 */
3463 		if (len != olen)
3464 			return -EINVAL;
3465 
3466 		/* Check for overlapping ranges */
3467 		if (dst_loff + len > loff && dst_loff < loff + len)
3468 			return -EINVAL;
3469 
3470 		same_lock_start = min_t(u64, loff, dst_loff);
3471 		same_lock_len = max_t(u64, loff, dst_loff) + len - same_lock_start;
3472 	} else {
3473 		/*
3474 		 * If the source and destination inodes are different, the
3475 		 * source's range end offset matches the source's i_size, that
3476 		 * i_size is not a multiple of the sector size, and the
3477 		 * destination range does not go past the destination's i_size,
3478 		 * we must round down the length to the nearest sector size
3479 		 * multiple. If we don't do this adjustment we end replacing
3480 		 * with zeroes the bytes in the range that starts at the
3481 		 * deduplication range's end offset and ends at the next sector
3482 		 * size multiple.
3483 		 */
3484 		if (loff + olen == i_size_read(src) &&
3485 		    dst_loff + len < i_size_read(dst)) {
3486 			const u64 sz = BTRFS_I(src)->root->fs_info->sectorsize;
3487 
3488 			len = round_down(i_size_read(src), sz) - loff;
3489 			olen = len;
3490 		}
3491 	}
3492 
3493 again:
3494 	ret = btrfs_cmp_data_prepare(src, loff, dst, dst_loff, olen, cmp);
3495 	if (ret)
3496 		return ret;
3497 
3498 	if (same_inode)
3499 		ret = lock_extent_range(src, same_lock_start, same_lock_len,
3500 					false);
3501 	else
3502 		ret = btrfs_double_extent_lock(src, loff, dst, dst_loff, len,
3503 					       false);
3504 	/*
3505 	 * If one of the inodes has dirty pages in the respective range or
3506 	 * ordered extents, we need to flush dellaloc and wait for all ordered
3507 	 * extents in the range. We must unlock the pages and the ranges in the
3508 	 * io trees to avoid deadlocks when flushing delalloc (requires locking
3509 	 * pages) and when waiting for ordered extents to complete (they require
3510 	 * range locking).
3511 	 */
3512 	if (ret == -EAGAIN) {
3513 		/*
3514 		 * Ranges in the io trees already unlocked. Now unlock all
3515 		 * pages before waiting for all IO to complete.
3516 		 */
3517 		btrfs_cmp_data_free(cmp);
3518 		if (same_inode) {
3519 			btrfs_wait_ordered_range(src, same_lock_start,
3520 						 same_lock_len);
3521 		} else {
3522 			btrfs_wait_ordered_range(src, loff, len);
3523 			btrfs_wait_ordered_range(dst, dst_loff, len);
3524 		}
3525 		goto again;
3526 	}
3527 	ASSERT(ret == 0);
3528 	if (WARN_ON(ret)) {
3529 		/* ranges in the io trees already unlocked */
3530 		btrfs_cmp_data_free(cmp);
3531 		return ret;
3532 	}
3533 
3534 	/* pass original length for comparison so we stay within i_size */
3535 	ret = btrfs_cmp_data(olen, cmp);
3536 	if (ret == 0)
3537 		ret = btrfs_clone(src, dst, loff, olen, len, dst_loff, 1);
3538 
3539 	if (same_inode)
3540 		unlock_extent(&BTRFS_I(src)->io_tree, same_lock_start,
3541 			      same_lock_start + same_lock_len - 1);
3542 	else
3543 		btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
3544 
3545 	btrfs_cmp_data_free(cmp);
3546 
3547 	return ret;
3548 }
3549 
3550 #define BTRFS_MAX_DEDUPE_LEN	SZ_16M
3551 
3552 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
3553 			     struct inode *dst, u64 dst_loff)
3554 {
3555 	int ret;
3556 	struct cmp_pages cmp;
3557 	int num_pages = PAGE_ALIGN(BTRFS_MAX_DEDUPE_LEN) >> PAGE_SHIFT;
3558 	bool same_inode = (src == dst);
3559 	u64 i, tail_len, chunk_count;
3560 
3561 	if (olen == 0)
3562 		return 0;
3563 
3564 	if (same_inode)
3565 		inode_lock(src);
3566 	else
3567 		btrfs_double_inode_lock(src, dst);
3568 
3569 	/* don't make the dst file partly checksummed */
3570 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3571 	    (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
3572 		ret = -EINVAL;
3573 		goto out_unlock;
3574 	}
3575 
3576 	tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
3577 	chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
3578 	if (chunk_count == 0)
3579 		num_pages = PAGE_ALIGN(tail_len) >> PAGE_SHIFT;
3580 
3581 	/*
3582 	 * If deduping ranges in the same inode, locking rules make it
3583 	 * mandatory to always lock pages in ascending order to avoid deadlocks
3584 	 * with concurrent tasks (such as starting writeback/delalloc).
3585 	 */
3586 	if (same_inode && dst_loff < loff)
3587 		swap(loff, dst_loff);
3588 
3589 	/*
3590 	 * We must gather up all the pages before we initiate our extent
3591 	 * locking. We use an array for the page pointers. Size of the array is
3592 	 * bounded by len, which is in turn bounded by BTRFS_MAX_DEDUPE_LEN.
3593 	 */
3594 	cmp.src_pages = kvmalloc_array(num_pages, sizeof(struct page *),
3595 				       GFP_KERNEL | __GFP_ZERO);
3596 	cmp.dst_pages = kvmalloc_array(num_pages, sizeof(struct page *),
3597 				       GFP_KERNEL | __GFP_ZERO);
3598 	if (!cmp.src_pages || !cmp.dst_pages) {
3599 		ret = -ENOMEM;
3600 		goto out_free;
3601 	}
3602 
3603 	for (i = 0; i < chunk_count; i++) {
3604 		ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
3605 					      dst, dst_loff, &cmp);
3606 		if (ret)
3607 			goto out_free;
3608 
3609 		loff += BTRFS_MAX_DEDUPE_LEN;
3610 		dst_loff += BTRFS_MAX_DEDUPE_LEN;
3611 	}
3612 
3613 	if (tail_len > 0)
3614 		ret = btrfs_extent_same_range(src, loff, tail_len, dst,
3615 					      dst_loff, &cmp);
3616 
3617 out_free:
3618 	kvfree(cmp.src_pages);
3619 	kvfree(cmp.dst_pages);
3620 
3621 out_unlock:
3622 	if (same_inode)
3623 		inode_unlock(src);
3624 	else
3625 		btrfs_double_inode_unlock(src, dst);
3626 
3627 	return ret;
3628 }
3629 
3630 int btrfs_dedupe_file_range(struct file *src_file, loff_t src_loff,
3631 			    struct file *dst_file, loff_t dst_loff,
3632 			    u64 olen)
3633 {
3634 	struct inode *src = file_inode(src_file);
3635 	struct inode *dst = file_inode(dst_file);
3636 	u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
3637 
3638 	if (WARN_ON_ONCE(bs < PAGE_SIZE)) {
3639 		/*
3640 		 * Btrfs does not support blocksize < page_size. As a
3641 		 * result, btrfs_cmp_data() won't correctly handle
3642 		 * this situation without an update.
3643 		 */
3644 		return -EINVAL;
3645 	}
3646 
3647 	return btrfs_extent_same(src, src_loff, olen, dst, dst_loff);
3648 }
3649 
3650 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
3651 				     struct inode *inode,
3652 				     u64 endoff,
3653 				     const u64 destoff,
3654 				     const u64 olen,
3655 				     int no_time_update)
3656 {
3657 	struct btrfs_root *root = BTRFS_I(inode)->root;
3658 	int ret;
3659 
3660 	inode_inc_iversion(inode);
3661 	if (!no_time_update)
3662 		inode->i_mtime = inode->i_ctime = current_time(inode);
3663 	/*
3664 	 * We round up to the block size at eof when determining which
3665 	 * extents to clone above, but shouldn't round up the file size.
3666 	 */
3667 	if (endoff > destoff + olen)
3668 		endoff = destoff + olen;
3669 	if (endoff > inode->i_size)
3670 		btrfs_i_size_write(BTRFS_I(inode), endoff);
3671 
3672 	ret = btrfs_update_inode(trans, root, inode);
3673 	if (ret) {
3674 		btrfs_abort_transaction(trans, ret);
3675 		btrfs_end_transaction(trans);
3676 		goto out;
3677 	}
3678 	ret = btrfs_end_transaction(trans);
3679 out:
3680 	return ret;
3681 }
3682 
3683 static void clone_update_extent_map(struct btrfs_inode *inode,
3684 				    const struct btrfs_trans_handle *trans,
3685 				    const struct btrfs_path *path,
3686 				    const u64 hole_offset,
3687 				    const u64 hole_len)
3688 {
3689 	struct extent_map_tree *em_tree = &inode->extent_tree;
3690 	struct extent_map *em;
3691 	int ret;
3692 
3693 	em = alloc_extent_map();
3694 	if (!em) {
3695 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
3696 		return;
3697 	}
3698 
3699 	if (path) {
3700 		struct btrfs_file_extent_item *fi;
3701 
3702 		fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
3703 				    struct btrfs_file_extent_item);
3704 		btrfs_extent_item_to_extent_map(inode, path, fi, false, em);
3705 		em->generation = -1;
3706 		if (btrfs_file_extent_type(path->nodes[0], fi) ==
3707 		    BTRFS_FILE_EXTENT_INLINE)
3708 			set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3709 					&inode->runtime_flags);
3710 	} else {
3711 		em->start = hole_offset;
3712 		em->len = hole_len;
3713 		em->ram_bytes = em->len;
3714 		em->orig_start = hole_offset;
3715 		em->block_start = EXTENT_MAP_HOLE;
3716 		em->block_len = 0;
3717 		em->orig_block_len = 0;
3718 		em->compress_type = BTRFS_COMPRESS_NONE;
3719 		em->generation = trans->transid;
3720 	}
3721 
3722 	while (1) {
3723 		write_lock(&em_tree->lock);
3724 		ret = add_extent_mapping(em_tree, em, 1);
3725 		write_unlock(&em_tree->lock);
3726 		if (ret != -EEXIST) {
3727 			free_extent_map(em);
3728 			break;
3729 		}
3730 		btrfs_drop_extent_cache(inode, em->start,
3731 					em->start + em->len - 1, 0);
3732 	}
3733 
3734 	if (ret)
3735 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
3736 }
3737 
3738 /*
3739  * Make sure we do not end up inserting an inline extent into a file that has
3740  * already other (non-inline) extents. If a file has an inline extent it can
3741  * not have any other extents and the (single) inline extent must start at the
3742  * file offset 0. Failing to respect these rules will lead to file corruption,
3743  * resulting in EIO errors on read/write operations, hitting BUG_ON's in mm, etc
3744  *
3745  * We can have extents that have been already written to disk or we can have
3746  * dirty ranges still in delalloc, in which case the extent maps and items are
3747  * created only when we run delalloc, and the delalloc ranges might fall outside
3748  * the range we are currently locking in the inode's io tree. So we check the
3749  * inode's i_size because of that (i_size updates are done while holding the
3750  * i_mutex, which we are holding here).
3751  * We also check to see if the inode has a size not greater than "datal" but has
3752  * extents beyond it, due to an fallocate with FALLOC_FL_KEEP_SIZE (and we are
3753  * protected against such concurrent fallocate calls by the i_mutex).
3754  *
3755  * If the file has no extents but a size greater than datal, do not allow the
3756  * copy because we would need turn the inline extent into a non-inline one (even
3757  * with NO_HOLES enabled). If we find our destination inode only has one inline
3758  * extent, just overwrite it with the source inline extent if its size is less
3759  * than the source extent's size, or we could copy the source inline extent's
3760  * data into the destination inode's inline extent if the later is greater then
3761  * the former.
3762  */
3763 static int clone_copy_inline_extent(struct inode *dst,
3764 				    struct btrfs_trans_handle *trans,
3765 				    struct btrfs_path *path,
3766 				    struct btrfs_key *new_key,
3767 				    const u64 drop_start,
3768 				    const u64 datal,
3769 				    const u64 skip,
3770 				    const u64 size,
3771 				    char *inline_data)
3772 {
3773 	struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
3774 	struct btrfs_root *root = BTRFS_I(dst)->root;
3775 	const u64 aligned_end = ALIGN(new_key->offset + datal,
3776 				      fs_info->sectorsize);
3777 	int ret;
3778 	struct btrfs_key key;
3779 
3780 	if (new_key->offset > 0)
3781 		return -EOPNOTSUPP;
3782 
3783 	key.objectid = btrfs_ino(BTRFS_I(dst));
3784 	key.type = BTRFS_EXTENT_DATA_KEY;
3785 	key.offset = 0;
3786 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3787 	if (ret < 0) {
3788 		return ret;
3789 	} else if (ret > 0) {
3790 		if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
3791 			ret = btrfs_next_leaf(root, path);
3792 			if (ret < 0)
3793 				return ret;
3794 			else if (ret > 0)
3795 				goto copy_inline_extent;
3796 		}
3797 		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3798 		if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
3799 		    key.type == BTRFS_EXTENT_DATA_KEY) {
3800 			ASSERT(key.offset > 0);
3801 			return -EOPNOTSUPP;
3802 		}
3803 	} else if (i_size_read(dst) <= datal) {
3804 		struct btrfs_file_extent_item *ei;
3805 		u64 ext_len;
3806 
3807 		/*
3808 		 * If the file size is <= datal, make sure there are no other
3809 		 * extents following (can happen do to an fallocate call with
3810 		 * the flag FALLOC_FL_KEEP_SIZE).
3811 		 */
3812 		ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3813 				    struct btrfs_file_extent_item);
3814 		/*
3815 		 * If it's an inline extent, it can not have other extents
3816 		 * following it.
3817 		 */
3818 		if (btrfs_file_extent_type(path->nodes[0], ei) ==
3819 		    BTRFS_FILE_EXTENT_INLINE)
3820 			goto copy_inline_extent;
3821 
3822 		ext_len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
3823 		if (ext_len > aligned_end)
3824 			return -EOPNOTSUPP;
3825 
3826 		ret = btrfs_next_item(root, path);
3827 		if (ret < 0) {
3828 			return ret;
3829 		} else if (ret == 0) {
3830 			btrfs_item_key_to_cpu(path->nodes[0], &key,
3831 					      path->slots[0]);
3832 			if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
3833 			    key.type == BTRFS_EXTENT_DATA_KEY)
3834 				return -EOPNOTSUPP;
3835 		}
3836 	}
3837 
3838 copy_inline_extent:
3839 	/*
3840 	 * We have no extent items, or we have an extent at offset 0 which may
3841 	 * or may not be inlined. All these cases are dealt the same way.
3842 	 */
3843 	if (i_size_read(dst) > datal) {
3844 		/*
3845 		 * If the destination inode has an inline extent...
3846 		 * This would require copying the data from the source inline
3847 		 * extent into the beginning of the destination's inline extent.
3848 		 * But this is really complex, both extents can be compressed
3849 		 * or just one of them, which would require decompressing and
3850 		 * re-compressing data (which could increase the new compressed
3851 		 * size, not allowing the compressed data to fit anymore in an
3852 		 * inline extent).
3853 		 * So just don't support this case for now (it should be rare,
3854 		 * we are not really saving space when cloning inline extents).
3855 		 */
3856 		return -EOPNOTSUPP;
3857 	}
3858 
3859 	btrfs_release_path(path);
3860 	ret = btrfs_drop_extents(trans, root, dst, drop_start, aligned_end, 1);
3861 	if (ret)
3862 		return ret;
3863 	ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
3864 	if (ret)
3865 		return ret;
3866 
3867 	if (skip) {
3868 		const u32 start = btrfs_file_extent_calc_inline_size(0);
3869 
3870 		memmove(inline_data + start, inline_data + start + skip, datal);
3871 	}
3872 
3873 	write_extent_buffer(path->nodes[0], inline_data,
3874 			    btrfs_item_ptr_offset(path->nodes[0],
3875 						  path->slots[0]),
3876 			    size);
3877 	inode_add_bytes(dst, datal);
3878 
3879 	return 0;
3880 }
3881 
3882 /**
3883  * btrfs_clone() - clone a range from inode file to another
3884  *
3885  * @src: Inode to clone from
3886  * @inode: Inode to clone to
3887  * @off: Offset within source to start clone from
3888  * @olen: Original length, passed by user, of range to clone
3889  * @olen_aligned: Block-aligned value of olen
3890  * @destoff: Offset within @inode to start clone
3891  * @no_time_update: Whether to update mtime/ctime on the target inode
3892  */
3893 static int btrfs_clone(struct inode *src, struct inode *inode,
3894 		       const u64 off, const u64 olen, const u64 olen_aligned,
3895 		       const u64 destoff, int no_time_update)
3896 {
3897 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3898 	struct btrfs_root *root = BTRFS_I(inode)->root;
3899 	struct btrfs_path *path = NULL;
3900 	struct extent_buffer *leaf;
3901 	struct btrfs_trans_handle *trans;
3902 	char *buf = NULL;
3903 	struct btrfs_key key;
3904 	u32 nritems;
3905 	int slot;
3906 	int ret;
3907 	const u64 len = olen_aligned;
3908 	u64 last_dest_end = destoff;
3909 
3910 	ret = -ENOMEM;
3911 	buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
3912 	if (!buf)
3913 		return ret;
3914 
3915 	path = btrfs_alloc_path();
3916 	if (!path) {
3917 		kvfree(buf);
3918 		return ret;
3919 	}
3920 
3921 	path->reada = READA_FORWARD;
3922 	/* clone data */
3923 	key.objectid = btrfs_ino(BTRFS_I(src));
3924 	key.type = BTRFS_EXTENT_DATA_KEY;
3925 	key.offset = off;
3926 
3927 	while (1) {
3928 		u64 next_key_min_offset = key.offset + 1;
3929 
3930 		/*
3931 		 * note the key will change type as we walk through the
3932 		 * tree.
3933 		 */
3934 		path->leave_spinning = 1;
3935 		ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
3936 				0, 0);
3937 		if (ret < 0)
3938 			goto out;
3939 		/*
3940 		 * First search, if no extent item that starts at offset off was
3941 		 * found but the previous item is an extent item, it's possible
3942 		 * it might overlap our target range, therefore process it.
3943 		 */
3944 		if (key.offset == off && ret > 0 && path->slots[0] > 0) {
3945 			btrfs_item_key_to_cpu(path->nodes[0], &key,
3946 					      path->slots[0] - 1);
3947 			if (key.type == BTRFS_EXTENT_DATA_KEY)
3948 				path->slots[0]--;
3949 		}
3950 
3951 		nritems = btrfs_header_nritems(path->nodes[0]);
3952 process_slot:
3953 		if (path->slots[0] >= nritems) {
3954 			ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
3955 			if (ret < 0)
3956 				goto out;
3957 			if (ret > 0)
3958 				break;
3959 			nritems = btrfs_header_nritems(path->nodes[0]);
3960 		}
3961 		leaf = path->nodes[0];
3962 		slot = path->slots[0];
3963 
3964 		btrfs_item_key_to_cpu(leaf, &key, slot);
3965 		if (key.type > BTRFS_EXTENT_DATA_KEY ||
3966 		    key.objectid != btrfs_ino(BTRFS_I(src)))
3967 			break;
3968 
3969 		if (key.type == BTRFS_EXTENT_DATA_KEY) {
3970 			struct btrfs_file_extent_item *extent;
3971 			int type;
3972 			u32 size;
3973 			struct btrfs_key new_key;
3974 			u64 disko = 0, diskl = 0;
3975 			u64 datao = 0, datal = 0;
3976 			u8 comp;
3977 			u64 drop_start;
3978 
3979 			extent = btrfs_item_ptr(leaf, slot,
3980 						struct btrfs_file_extent_item);
3981 			comp = btrfs_file_extent_compression(leaf, extent);
3982 			type = btrfs_file_extent_type(leaf, extent);
3983 			if (type == BTRFS_FILE_EXTENT_REG ||
3984 			    type == BTRFS_FILE_EXTENT_PREALLOC) {
3985 				disko = btrfs_file_extent_disk_bytenr(leaf,
3986 								      extent);
3987 				diskl = btrfs_file_extent_disk_num_bytes(leaf,
3988 								 extent);
3989 				datao = btrfs_file_extent_offset(leaf, extent);
3990 				datal = btrfs_file_extent_num_bytes(leaf,
3991 								    extent);
3992 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
3993 				/* take upper bound, may be compressed */
3994 				datal = btrfs_file_extent_ram_bytes(leaf,
3995 								    extent);
3996 			}
3997 
3998 			/*
3999 			 * The first search might have left us at an extent
4000 			 * item that ends before our target range's start, can
4001 			 * happen if we have holes and NO_HOLES feature enabled.
4002 			 */
4003 			if (key.offset + datal <= off) {
4004 				path->slots[0]++;
4005 				goto process_slot;
4006 			} else if (key.offset >= off + len) {
4007 				break;
4008 			}
4009 			next_key_min_offset = key.offset + datal;
4010 			size = btrfs_item_size_nr(leaf, slot);
4011 			read_extent_buffer(leaf, buf,
4012 					   btrfs_item_ptr_offset(leaf, slot),
4013 					   size);
4014 
4015 			btrfs_release_path(path);
4016 			path->leave_spinning = 0;
4017 
4018 			memcpy(&new_key, &key, sizeof(new_key));
4019 			new_key.objectid = btrfs_ino(BTRFS_I(inode));
4020 			if (off <= key.offset)
4021 				new_key.offset = key.offset + destoff - off;
4022 			else
4023 				new_key.offset = destoff;
4024 
4025 			/*
4026 			 * Deal with a hole that doesn't have an extent item
4027 			 * that represents it (NO_HOLES feature enabled).
4028 			 * This hole is either in the middle of the cloning
4029 			 * range or at the beginning (fully overlaps it or
4030 			 * partially overlaps it).
4031 			 */
4032 			if (new_key.offset != last_dest_end)
4033 				drop_start = last_dest_end;
4034 			else
4035 				drop_start = new_key.offset;
4036 
4037 			/*
4038 			 * 1 - adjusting old extent (we may have to split it)
4039 			 * 1 - add new extent
4040 			 * 1 - inode update
4041 			 */
4042 			trans = btrfs_start_transaction(root, 3);
4043 			if (IS_ERR(trans)) {
4044 				ret = PTR_ERR(trans);
4045 				goto out;
4046 			}
4047 
4048 			if (type == BTRFS_FILE_EXTENT_REG ||
4049 			    type == BTRFS_FILE_EXTENT_PREALLOC) {
4050 				/*
4051 				 *    a  | --- range to clone ---|  b
4052 				 * | ------------- extent ------------- |
4053 				 */
4054 
4055 				/* subtract range b */
4056 				if (key.offset + datal > off + len)
4057 					datal = off + len - key.offset;
4058 
4059 				/* subtract range a */
4060 				if (off > key.offset) {
4061 					datao += off - key.offset;
4062 					datal -= off - key.offset;
4063 				}
4064 
4065 				ret = btrfs_drop_extents(trans, root, inode,
4066 							 drop_start,
4067 							 new_key.offset + datal,
4068 							 1);
4069 				if (ret) {
4070 					if (ret != -EOPNOTSUPP)
4071 						btrfs_abort_transaction(trans,
4072 									ret);
4073 					btrfs_end_transaction(trans);
4074 					goto out;
4075 				}
4076 
4077 				ret = btrfs_insert_empty_item(trans, root, path,
4078 							      &new_key, size);
4079 				if (ret) {
4080 					btrfs_abort_transaction(trans, ret);
4081 					btrfs_end_transaction(trans);
4082 					goto out;
4083 				}
4084 
4085 				leaf = path->nodes[0];
4086 				slot = path->slots[0];
4087 				write_extent_buffer(leaf, buf,
4088 					    btrfs_item_ptr_offset(leaf, slot),
4089 					    size);
4090 
4091 				extent = btrfs_item_ptr(leaf, slot,
4092 						struct btrfs_file_extent_item);
4093 
4094 				/* disko == 0 means it's a hole */
4095 				if (!disko)
4096 					datao = 0;
4097 
4098 				btrfs_set_file_extent_offset(leaf, extent,
4099 							     datao);
4100 				btrfs_set_file_extent_num_bytes(leaf, extent,
4101 								datal);
4102 
4103 				if (disko) {
4104 					inode_add_bytes(inode, datal);
4105 					ret = btrfs_inc_extent_ref(trans,
4106 							root,
4107 							disko, diskl, 0,
4108 							root->root_key.objectid,
4109 							btrfs_ino(BTRFS_I(inode)),
4110 							new_key.offset - datao);
4111 					if (ret) {
4112 						btrfs_abort_transaction(trans,
4113 									ret);
4114 						btrfs_end_transaction(trans);
4115 						goto out;
4116 
4117 					}
4118 				}
4119 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
4120 				u64 skip = 0;
4121 				u64 trim = 0;
4122 
4123 				if (off > key.offset) {
4124 					skip = off - key.offset;
4125 					new_key.offset += skip;
4126 				}
4127 
4128 				if (key.offset + datal > off + len)
4129 					trim = key.offset + datal - (off + len);
4130 
4131 				if (comp && (skip || trim)) {
4132 					ret = -EINVAL;
4133 					btrfs_end_transaction(trans);
4134 					goto out;
4135 				}
4136 				size -= skip + trim;
4137 				datal -= skip + trim;
4138 
4139 				ret = clone_copy_inline_extent(inode,
4140 							       trans, path,
4141 							       &new_key,
4142 							       drop_start,
4143 							       datal,
4144 							       skip, size, buf);
4145 				if (ret) {
4146 					if (ret != -EOPNOTSUPP)
4147 						btrfs_abort_transaction(trans,
4148 									ret);
4149 					btrfs_end_transaction(trans);
4150 					goto out;
4151 				}
4152 				leaf = path->nodes[0];
4153 				slot = path->slots[0];
4154 			}
4155 
4156 			/* If we have an implicit hole (NO_HOLES feature). */
4157 			if (drop_start < new_key.offset)
4158 				clone_update_extent_map(BTRFS_I(inode), trans,
4159 						NULL, drop_start,
4160 						new_key.offset - drop_start);
4161 
4162 			clone_update_extent_map(BTRFS_I(inode), trans,
4163 					path, 0, 0);
4164 
4165 			btrfs_mark_buffer_dirty(leaf);
4166 			btrfs_release_path(path);
4167 
4168 			last_dest_end = ALIGN(new_key.offset + datal,
4169 					      fs_info->sectorsize);
4170 			ret = clone_finish_inode_update(trans, inode,
4171 							last_dest_end,
4172 							destoff, olen,
4173 							no_time_update);
4174 			if (ret)
4175 				goto out;
4176 			if (new_key.offset + datal >= destoff + len)
4177 				break;
4178 		}
4179 		btrfs_release_path(path);
4180 		key.offset = next_key_min_offset;
4181 
4182 		if (fatal_signal_pending(current)) {
4183 			ret = -EINTR;
4184 			goto out;
4185 		}
4186 	}
4187 	ret = 0;
4188 
4189 	if (last_dest_end < destoff + len) {
4190 		/*
4191 		 * We have an implicit hole (NO_HOLES feature is enabled) that
4192 		 * fully or partially overlaps our cloning range at its end.
4193 		 */
4194 		btrfs_release_path(path);
4195 
4196 		/*
4197 		 * 1 - remove extent(s)
4198 		 * 1 - inode update
4199 		 */
4200 		trans = btrfs_start_transaction(root, 2);
4201 		if (IS_ERR(trans)) {
4202 			ret = PTR_ERR(trans);
4203 			goto out;
4204 		}
4205 		ret = btrfs_drop_extents(trans, root, inode,
4206 					 last_dest_end, destoff + len, 1);
4207 		if (ret) {
4208 			if (ret != -EOPNOTSUPP)
4209 				btrfs_abort_transaction(trans, ret);
4210 			btrfs_end_transaction(trans);
4211 			goto out;
4212 		}
4213 		clone_update_extent_map(BTRFS_I(inode), trans, NULL,
4214 				last_dest_end,
4215 				destoff + len - last_dest_end);
4216 		ret = clone_finish_inode_update(trans, inode, destoff + len,
4217 						destoff, olen, no_time_update);
4218 	}
4219 
4220 out:
4221 	btrfs_free_path(path);
4222 	kvfree(buf);
4223 	return ret;
4224 }
4225 
4226 static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
4227 					u64 off, u64 olen, u64 destoff)
4228 {
4229 	struct inode *inode = file_inode(file);
4230 	struct inode *src = file_inode(file_src);
4231 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4232 	struct btrfs_root *root = BTRFS_I(inode)->root;
4233 	int ret;
4234 	u64 len = olen;
4235 	u64 bs = fs_info->sb->s_blocksize;
4236 	int same_inode = src == inode;
4237 
4238 	/*
4239 	 * TODO:
4240 	 * - split compressed inline extents.  annoying: we need to
4241 	 *   decompress into destination's address_space (the file offset
4242 	 *   may change, so source mapping won't do), then recompress (or
4243 	 *   otherwise reinsert) a subrange.
4244 	 *
4245 	 * - split destination inode's inline extents.  The inline extents can
4246 	 *   be either compressed or non-compressed.
4247 	 */
4248 
4249 	if (btrfs_root_readonly(root))
4250 		return -EROFS;
4251 
4252 	if (file_src->f_path.mnt != file->f_path.mnt ||
4253 	    src->i_sb != inode->i_sb)
4254 		return -EXDEV;
4255 
4256 	if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
4257 		return -EISDIR;
4258 
4259 	if (!same_inode) {
4260 		btrfs_double_inode_lock(src, inode);
4261 	} else {
4262 		inode_lock(src);
4263 	}
4264 
4265 	/* don't make the dst file partly checksummed */
4266 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
4267 	    (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
4268 		ret = -EINVAL;
4269 		goto out_unlock;
4270 	}
4271 
4272 	/* determine range to clone */
4273 	ret = -EINVAL;
4274 	if (off + len > src->i_size || off + len < off)
4275 		goto out_unlock;
4276 	if (len == 0)
4277 		olen = len = src->i_size - off;
4278 	/* if we extend to eof, continue to block boundary */
4279 	if (off + len == src->i_size)
4280 		len = ALIGN(src->i_size, bs) - off;
4281 
4282 	if (len == 0) {
4283 		ret = 0;
4284 		goto out_unlock;
4285 	}
4286 
4287 	/* verify the end result is block aligned */
4288 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
4289 	    !IS_ALIGNED(destoff, bs))
4290 		goto out_unlock;
4291 
4292 	/* verify if ranges are overlapped within the same file */
4293 	if (same_inode) {
4294 		if (destoff + len > off && destoff < off + len)
4295 			goto out_unlock;
4296 	}
4297 
4298 	if (destoff > inode->i_size) {
4299 		ret = btrfs_cont_expand(inode, inode->i_size, destoff);
4300 		if (ret)
4301 			goto out_unlock;
4302 	}
4303 
4304 	/*
4305 	 * Lock the target range too. Right after we replace the file extent
4306 	 * items in the fs tree (which now point to the cloned data), we might
4307 	 * have a worker replace them with extent items relative to a write
4308 	 * operation that was issued before this clone operation (i.e. confront
4309 	 * with inode.c:btrfs_finish_ordered_io).
4310 	 */
4311 	if (same_inode) {
4312 		u64 lock_start = min_t(u64, off, destoff);
4313 		u64 lock_len = max_t(u64, off, destoff) + len - lock_start;
4314 
4315 		ret = lock_extent_range(src, lock_start, lock_len, true);
4316 	} else {
4317 		ret = btrfs_double_extent_lock(src, off, inode, destoff, len,
4318 					       true);
4319 	}
4320 	ASSERT(ret == 0);
4321 	if (WARN_ON(ret)) {
4322 		/* ranges in the io trees already unlocked */
4323 		goto out_unlock;
4324 	}
4325 
4326 	ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
4327 
4328 	if (same_inode) {
4329 		u64 lock_start = min_t(u64, off, destoff);
4330 		u64 lock_end = max_t(u64, off, destoff) + len - 1;
4331 
4332 		unlock_extent(&BTRFS_I(src)->io_tree, lock_start, lock_end);
4333 	} else {
4334 		btrfs_double_extent_unlock(src, off, inode, destoff, len);
4335 	}
4336 	/*
4337 	 * Truncate page cache pages so that future reads will see the cloned
4338 	 * data immediately and not the previous data.
4339 	 */
4340 	truncate_inode_pages_range(&inode->i_data,
4341 				round_down(destoff, PAGE_SIZE),
4342 				round_up(destoff + len, PAGE_SIZE) - 1);
4343 out_unlock:
4344 	if (!same_inode)
4345 		btrfs_double_inode_unlock(src, inode);
4346 	else
4347 		inode_unlock(src);
4348 	return ret;
4349 }
4350 
4351 int btrfs_clone_file_range(struct file *src_file, loff_t off,
4352 		struct file *dst_file, loff_t destoff, u64 len)
4353 {
4354 	return btrfs_clone_files(dst_file, src_file, off, len, destoff);
4355 }
4356 
4357 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
4358 {
4359 	struct inode *inode = file_inode(file);
4360 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4361 	struct btrfs_root *root = BTRFS_I(inode)->root;
4362 	struct btrfs_root *new_root;
4363 	struct btrfs_dir_item *di;
4364 	struct btrfs_trans_handle *trans;
4365 	struct btrfs_path *path;
4366 	struct btrfs_key location;
4367 	struct btrfs_disk_key disk_key;
4368 	u64 objectid = 0;
4369 	u64 dir_id;
4370 	int ret;
4371 
4372 	if (!capable(CAP_SYS_ADMIN))
4373 		return -EPERM;
4374 
4375 	ret = mnt_want_write_file(file);
4376 	if (ret)
4377 		return ret;
4378 
4379 	if (copy_from_user(&objectid, argp, sizeof(objectid))) {
4380 		ret = -EFAULT;
4381 		goto out;
4382 	}
4383 
4384 	if (!objectid)
4385 		objectid = BTRFS_FS_TREE_OBJECTID;
4386 
4387 	location.objectid = objectid;
4388 	location.type = BTRFS_ROOT_ITEM_KEY;
4389 	location.offset = (u64)-1;
4390 
4391 	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
4392 	if (IS_ERR(new_root)) {
4393 		ret = PTR_ERR(new_root);
4394 		goto out;
4395 	}
4396 	if (!is_fstree(new_root->objectid)) {
4397 		ret = -ENOENT;
4398 		goto out;
4399 	}
4400 
4401 	path = btrfs_alloc_path();
4402 	if (!path) {
4403 		ret = -ENOMEM;
4404 		goto out;
4405 	}
4406 	path->leave_spinning = 1;
4407 
4408 	trans = btrfs_start_transaction(root, 1);
4409 	if (IS_ERR(trans)) {
4410 		btrfs_free_path(path);
4411 		ret = PTR_ERR(trans);
4412 		goto out;
4413 	}
4414 
4415 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
4416 	di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
4417 				   dir_id, "default", 7, 1);
4418 	if (IS_ERR_OR_NULL(di)) {
4419 		btrfs_free_path(path);
4420 		btrfs_end_transaction(trans);
4421 		btrfs_err(fs_info,
4422 			  "Umm, you don't have the default diritem, this isn't going to work");
4423 		ret = -ENOENT;
4424 		goto out;
4425 	}
4426 
4427 	btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
4428 	btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
4429 	btrfs_mark_buffer_dirty(path->nodes[0]);
4430 	btrfs_free_path(path);
4431 
4432 	btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
4433 	btrfs_end_transaction(trans);
4434 out:
4435 	mnt_drop_write_file(file);
4436 	return ret;
4437 }
4438 
4439 static void get_block_group_info(struct list_head *groups_list,
4440 				 struct btrfs_ioctl_space_info *space)
4441 {
4442 	struct btrfs_block_group_cache *block_group;
4443 
4444 	space->total_bytes = 0;
4445 	space->used_bytes = 0;
4446 	space->flags = 0;
4447 	list_for_each_entry(block_group, groups_list, list) {
4448 		space->flags = block_group->flags;
4449 		space->total_bytes += block_group->key.offset;
4450 		space->used_bytes +=
4451 			btrfs_block_group_used(&block_group->item);
4452 	}
4453 }
4454 
4455 static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info,
4456 				   void __user *arg)
4457 {
4458 	struct btrfs_ioctl_space_args space_args;
4459 	struct btrfs_ioctl_space_info space;
4460 	struct btrfs_ioctl_space_info *dest;
4461 	struct btrfs_ioctl_space_info *dest_orig;
4462 	struct btrfs_ioctl_space_info __user *user_dest;
4463 	struct btrfs_space_info *info;
4464 	static const u64 types[] = {
4465 		BTRFS_BLOCK_GROUP_DATA,
4466 		BTRFS_BLOCK_GROUP_SYSTEM,
4467 		BTRFS_BLOCK_GROUP_METADATA,
4468 		BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA
4469 	};
4470 	int num_types = 4;
4471 	int alloc_size;
4472 	int ret = 0;
4473 	u64 slot_count = 0;
4474 	int i, c;
4475 
4476 	if (copy_from_user(&space_args,
4477 			   (struct btrfs_ioctl_space_args __user *)arg,
4478 			   sizeof(space_args)))
4479 		return -EFAULT;
4480 
4481 	for (i = 0; i < num_types; i++) {
4482 		struct btrfs_space_info *tmp;
4483 
4484 		info = NULL;
4485 		rcu_read_lock();
4486 		list_for_each_entry_rcu(tmp, &fs_info->space_info,
4487 					list) {
4488 			if (tmp->flags == types[i]) {
4489 				info = tmp;
4490 				break;
4491 			}
4492 		}
4493 		rcu_read_unlock();
4494 
4495 		if (!info)
4496 			continue;
4497 
4498 		down_read(&info->groups_sem);
4499 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4500 			if (!list_empty(&info->block_groups[c]))
4501 				slot_count++;
4502 		}
4503 		up_read(&info->groups_sem);
4504 	}
4505 
4506 	/*
4507 	 * Global block reserve, exported as a space_info
4508 	 */
4509 	slot_count++;
4510 
4511 	/* space_slots == 0 means they are asking for a count */
4512 	if (space_args.space_slots == 0) {
4513 		space_args.total_spaces = slot_count;
4514 		goto out;
4515 	}
4516 
4517 	slot_count = min_t(u64, space_args.space_slots, slot_count);
4518 
4519 	alloc_size = sizeof(*dest) * slot_count;
4520 
4521 	/* we generally have at most 6 or so space infos, one for each raid
4522 	 * level.  So, a whole page should be more than enough for everyone
4523 	 */
4524 	if (alloc_size > PAGE_SIZE)
4525 		return -ENOMEM;
4526 
4527 	space_args.total_spaces = 0;
4528 	dest = kmalloc(alloc_size, GFP_KERNEL);
4529 	if (!dest)
4530 		return -ENOMEM;
4531 	dest_orig = dest;
4532 
4533 	/* now we have a buffer to copy into */
4534 	for (i = 0; i < num_types; i++) {
4535 		struct btrfs_space_info *tmp;
4536 
4537 		if (!slot_count)
4538 			break;
4539 
4540 		info = NULL;
4541 		rcu_read_lock();
4542 		list_for_each_entry_rcu(tmp, &fs_info->space_info,
4543 					list) {
4544 			if (tmp->flags == types[i]) {
4545 				info = tmp;
4546 				break;
4547 			}
4548 		}
4549 		rcu_read_unlock();
4550 
4551 		if (!info)
4552 			continue;
4553 		down_read(&info->groups_sem);
4554 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4555 			if (!list_empty(&info->block_groups[c])) {
4556 				get_block_group_info(&info->block_groups[c],
4557 						     &space);
4558 				memcpy(dest, &space, sizeof(space));
4559 				dest++;
4560 				space_args.total_spaces++;
4561 				slot_count--;
4562 			}
4563 			if (!slot_count)
4564 				break;
4565 		}
4566 		up_read(&info->groups_sem);
4567 	}
4568 
4569 	/*
4570 	 * Add global block reserve
4571 	 */
4572 	if (slot_count) {
4573 		struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4574 
4575 		spin_lock(&block_rsv->lock);
4576 		space.total_bytes = block_rsv->size;
4577 		space.used_bytes = block_rsv->size - block_rsv->reserved;
4578 		spin_unlock(&block_rsv->lock);
4579 		space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
4580 		memcpy(dest, &space, sizeof(space));
4581 		space_args.total_spaces++;
4582 	}
4583 
4584 	user_dest = (struct btrfs_ioctl_space_info __user *)
4585 		(arg + sizeof(struct btrfs_ioctl_space_args));
4586 
4587 	if (copy_to_user(user_dest, dest_orig, alloc_size))
4588 		ret = -EFAULT;
4589 
4590 	kfree(dest_orig);
4591 out:
4592 	if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
4593 		ret = -EFAULT;
4594 
4595 	return ret;
4596 }
4597 
4598 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
4599 					    void __user *argp)
4600 {
4601 	struct btrfs_trans_handle *trans;
4602 	u64 transid;
4603 	int ret;
4604 
4605 	trans = btrfs_attach_transaction_barrier(root);
4606 	if (IS_ERR(trans)) {
4607 		if (PTR_ERR(trans) != -ENOENT)
4608 			return PTR_ERR(trans);
4609 
4610 		/* No running transaction, don't bother */
4611 		transid = root->fs_info->last_trans_committed;
4612 		goto out;
4613 	}
4614 	transid = trans->transid;
4615 	ret = btrfs_commit_transaction_async(trans, 0);
4616 	if (ret) {
4617 		btrfs_end_transaction(trans);
4618 		return ret;
4619 	}
4620 out:
4621 	if (argp)
4622 		if (copy_to_user(argp, &transid, sizeof(transid)))
4623 			return -EFAULT;
4624 	return 0;
4625 }
4626 
4627 static noinline long btrfs_ioctl_wait_sync(struct btrfs_fs_info *fs_info,
4628 					   void __user *argp)
4629 {
4630 	u64 transid;
4631 
4632 	if (argp) {
4633 		if (copy_from_user(&transid, argp, sizeof(transid)))
4634 			return -EFAULT;
4635 	} else {
4636 		transid = 0;  /* current trans */
4637 	}
4638 	return btrfs_wait_for_commit(fs_info, transid);
4639 }
4640 
4641 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
4642 {
4643 	struct btrfs_fs_info *fs_info = btrfs_sb(file_inode(file)->i_sb);
4644 	struct btrfs_ioctl_scrub_args *sa;
4645 	int ret;
4646 
4647 	if (!capable(CAP_SYS_ADMIN))
4648 		return -EPERM;
4649 
4650 	sa = memdup_user(arg, sizeof(*sa));
4651 	if (IS_ERR(sa))
4652 		return PTR_ERR(sa);
4653 
4654 	if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
4655 		ret = mnt_want_write_file(file);
4656 		if (ret)
4657 			goto out;
4658 	}
4659 
4660 	ret = btrfs_scrub_dev(fs_info, sa->devid, sa->start, sa->end,
4661 			      &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
4662 			      0);
4663 
4664 	if (copy_to_user(arg, sa, sizeof(*sa)))
4665 		ret = -EFAULT;
4666 
4667 	if (!(sa->flags & BTRFS_SCRUB_READONLY))
4668 		mnt_drop_write_file(file);
4669 out:
4670 	kfree(sa);
4671 	return ret;
4672 }
4673 
4674 static long btrfs_ioctl_scrub_cancel(struct btrfs_fs_info *fs_info)
4675 {
4676 	if (!capable(CAP_SYS_ADMIN))
4677 		return -EPERM;
4678 
4679 	return btrfs_scrub_cancel(fs_info);
4680 }
4681 
4682 static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
4683 				       void __user *arg)
4684 {
4685 	struct btrfs_ioctl_scrub_args *sa;
4686 	int ret;
4687 
4688 	if (!capable(CAP_SYS_ADMIN))
4689 		return -EPERM;
4690 
4691 	sa = memdup_user(arg, sizeof(*sa));
4692 	if (IS_ERR(sa))
4693 		return PTR_ERR(sa);
4694 
4695 	ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
4696 
4697 	if (copy_to_user(arg, sa, sizeof(*sa)))
4698 		ret = -EFAULT;
4699 
4700 	kfree(sa);
4701 	return ret;
4702 }
4703 
4704 static long btrfs_ioctl_get_dev_stats(struct btrfs_fs_info *fs_info,
4705 				      void __user *arg)
4706 {
4707 	struct btrfs_ioctl_get_dev_stats *sa;
4708 	int ret;
4709 
4710 	sa = memdup_user(arg, sizeof(*sa));
4711 	if (IS_ERR(sa))
4712 		return PTR_ERR(sa);
4713 
4714 	if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
4715 		kfree(sa);
4716 		return -EPERM;
4717 	}
4718 
4719 	ret = btrfs_get_dev_stats(fs_info, sa);
4720 
4721 	if (copy_to_user(arg, sa, sizeof(*sa)))
4722 		ret = -EFAULT;
4723 
4724 	kfree(sa);
4725 	return ret;
4726 }
4727 
4728 static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
4729 				    void __user *arg)
4730 {
4731 	struct btrfs_ioctl_dev_replace_args *p;
4732 	int ret;
4733 
4734 	if (!capable(CAP_SYS_ADMIN))
4735 		return -EPERM;
4736 
4737 	p = memdup_user(arg, sizeof(*p));
4738 	if (IS_ERR(p))
4739 		return PTR_ERR(p);
4740 
4741 	switch (p->cmd) {
4742 	case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
4743 		if (sb_rdonly(fs_info->sb)) {
4744 			ret = -EROFS;
4745 			goto out;
4746 		}
4747 		if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
4748 			ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4749 		} else {
4750 			ret = btrfs_dev_replace_by_ioctl(fs_info, p);
4751 			clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
4752 		}
4753 		break;
4754 	case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
4755 		btrfs_dev_replace_status(fs_info, p);
4756 		ret = 0;
4757 		break;
4758 	case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
4759 		p->result = btrfs_dev_replace_cancel(fs_info);
4760 		ret = 0;
4761 		break;
4762 	default:
4763 		ret = -EINVAL;
4764 		break;
4765 	}
4766 
4767 	if (copy_to_user(arg, p, sizeof(*p)))
4768 		ret = -EFAULT;
4769 out:
4770 	kfree(p);
4771 	return ret;
4772 }
4773 
4774 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
4775 {
4776 	int ret = 0;
4777 	int i;
4778 	u64 rel_ptr;
4779 	int size;
4780 	struct btrfs_ioctl_ino_path_args *ipa = NULL;
4781 	struct inode_fs_paths *ipath = NULL;
4782 	struct btrfs_path *path;
4783 
4784 	if (!capable(CAP_DAC_READ_SEARCH))
4785 		return -EPERM;
4786 
4787 	path = btrfs_alloc_path();
4788 	if (!path) {
4789 		ret = -ENOMEM;
4790 		goto out;
4791 	}
4792 
4793 	ipa = memdup_user(arg, sizeof(*ipa));
4794 	if (IS_ERR(ipa)) {
4795 		ret = PTR_ERR(ipa);
4796 		ipa = NULL;
4797 		goto out;
4798 	}
4799 
4800 	size = min_t(u32, ipa->size, 4096);
4801 	ipath = init_ipath(size, root, path);
4802 	if (IS_ERR(ipath)) {
4803 		ret = PTR_ERR(ipath);
4804 		ipath = NULL;
4805 		goto out;
4806 	}
4807 
4808 	ret = paths_from_inode(ipa->inum, ipath);
4809 	if (ret < 0)
4810 		goto out;
4811 
4812 	for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
4813 		rel_ptr = ipath->fspath->val[i] -
4814 			  (u64)(unsigned long)ipath->fspath->val;
4815 		ipath->fspath->val[i] = rel_ptr;
4816 	}
4817 
4818 	ret = copy_to_user((void __user *)(unsigned long)ipa->fspath,
4819 			   ipath->fspath, size);
4820 	if (ret) {
4821 		ret = -EFAULT;
4822 		goto out;
4823 	}
4824 
4825 out:
4826 	btrfs_free_path(path);
4827 	free_ipath(ipath);
4828 	kfree(ipa);
4829 
4830 	return ret;
4831 }
4832 
4833 static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
4834 {
4835 	struct btrfs_data_container *inodes = ctx;
4836 	const size_t c = 3 * sizeof(u64);
4837 
4838 	if (inodes->bytes_left >= c) {
4839 		inodes->bytes_left -= c;
4840 		inodes->val[inodes->elem_cnt] = inum;
4841 		inodes->val[inodes->elem_cnt + 1] = offset;
4842 		inodes->val[inodes->elem_cnt + 2] = root;
4843 		inodes->elem_cnt += 3;
4844 	} else {
4845 		inodes->bytes_missing += c - inodes->bytes_left;
4846 		inodes->bytes_left = 0;
4847 		inodes->elem_missed += 3;
4848 	}
4849 
4850 	return 0;
4851 }
4852 
4853 static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
4854 					void __user *arg, int version)
4855 {
4856 	int ret = 0;
4857 	int size;
4858 	struct btrfs_ioctl_logical_ino_args *loi;
4859 	struct btrfs_data_container *inodes = NULL;
4860 	struct btrfs_path *path = NULL;
4861 	bool ignore_offset;
4862 
4863 	if (!capable(CAP_SYS_ADMIN))
4864 		return -EPERM;
4865 
4866 	loi = memdup_user(arg, sizeof(*loi));
4867 	if (IS_ERR(loi))
4868 		return PTR_ERR(loi);
4869 
4870 	if (version == 1) {
4871 		ignore_offset = false;
4872 		size = min_t(u32, loi->size, SZ_64K);
4873 	} else {
4874 		/* All reserved bits must be 0 for now */
4875 		if (memchr_inv(loi->reserved, 0, sizeof(loi->reserved))) {
4876 			ret = -EINVAL;
4877 			goto out_loi;
4878 		}
4879 		/* Only accept flags we have defined so far */
4880 		if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) {
4881 			ret = -EINVAL;
4882 			goto out_loi;
4883 		}
4884 		ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET;
4885 		size = min_t(u32, loi->size, SZ_16M);
4886 	}
4887 
4888 	path = btrfs_alloc_path();
4889 	if (!path) {
4890 		ret = -ENOMEM;
4891 		goto out;
4892 	}
4893 
4894 	inodes = init_data_container(size);
4895 	if (IS_ERR(inodes)) {
4896 		ret = PTR_ERR(inodes);
4897 		inodes = NULL;
4898 		goto out;
4899 	}
4900 
4901 	ret = iterate_inodes_from_logical(loi->logical, fs_info, path,
4902 					  build_ino_list, inodes, ignore_offset);
4903 	if (ret == -EINVAL)
4904 		ret = -ENOENT;
4905 	if (ret < 0)
4906 		goto out;
4907 
4908 	ret = copy_to_user((void __user *)(unsigned long)loi->inodes, inodes,
4909 			   size);
4910 	if (ret)
4911 		ret = -EFAULT;
4912 
4913 out:
4914 	btrfs_free_path(path);
4915 	kvfree(inodes);
4916 out_loi:
4917 	kfree(loi);
4918 
4919 	return ret;
4920 }
4921 
4922 void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
4923 			       struct btrfs_ioctl_balance_args *bargs)
4924 {
4925 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4926 
4927 	bargs->flags = bctl->flags;
4928 
4929 	if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags))
4930 		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
4931 	if (atomic_read(&fs_info->balance_pause_req))
4932 		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
4933 	if (atomic_read(&fs_info->balance_cancel_req))
4934 		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
4935 
4936 	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
4937 	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
4938 	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
4939 
4940 	spin_lock(&fs_info->balance_lock);
4941 	memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4942 	spin_unlock(&fs_info->balance_lock);
4943 }
4944 
4945 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
4946 {
4947 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4948 	struct btrfs_fs_info *fs_info = root->fs_info;
4949 	struct btrfs_ioctl_balance_args *bargs;
4950 	struct btrfs_balance_control *bctl;
4951 	bool need_unlock; /* for mut. excl. ops lock */
4952 	int ret;
4953 
4954 	if (!capable(CAP_SYS_ADMIN))
4955 		return -EPERM;
4956 
4957 	ret = mnt_want_write_file(file);
4958 	if (ret)
4959 		return ret;
4960 
4961 again:
4962 	if (!test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
4963 		mutex_lock(&fs_info->balance_mutex);
4964 		need_unlock = true;
4965 		goto locked;
4966 	}
4967 
4968 	/*
4969 	 * mut. excl. ops lock is locked.  Three possibilities:
4970 	 *   (1) some other op is running
4971 	 *   (2) balance is running
4972 	 *   (3) balance is paused -- special case (think resume)
4973 	 */
4974 	mutex_lock(&fs_info->balance_mutex);
4975 	if (fs_info->balance_ctl) {
4976 		/* this is either (2) or (3) */
4977 		if (!test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
4978 			mutex_unlock(&fs_info->balance_mutex);
4979 			/*
4980 			 * Lock released to allow other waiters to continue,
4981 			 * we'll reexamine the status again.
4982 			 */
4983 			mutex_lock(&fs_info->balance_mutex);
4984 
4985 			if (fs_info->balance_ctl &&
4986 			    !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
4987 				/* this is (3) */
4988 				need_unlock = false;
4989 				goto locked;
4990 			}
4991 
4992 			mutex_unlock(&fs_info->balance_mutex);
4993 			goto again;
4994 		} else {
4995 			/* this is (2) */
4996 			mutex_unlock(&fs_info->balance_mutex);
4997 			ret = -EINPROGRESS;
4998 			goto out;
4999 		}
5000 	} else {
5001 		/* this is (1) */
5002 		mutex_unlock(&fs_info->balance_mutex);
5003 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
5004 		goto out;
5005 	}
5006 
5007 locked:
5008 	BUG_ON(!test_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
5009 
5010 	if (arg) {
5011 		bargs = memdup_user(arg, sizeof(*bargs));
5012 		if (IS_ERR(bargs)) {
5013 			ret = PTR_ERR(bargs);
5014 			goto out_unlock;
5015 		}
5016 
5017 		if (bargs->flags & BTRFS_BALANCE_RESUME) {
5018 			if (!fs_info->balance_ctl) {
5019 				ret = -ENOTCONN;
5020 				goto out_bargs;
5021 			}
5022 
5023 			bctl = fs_info->balance_ctl;
5024 			spin_lock(&fs_info->balance_lock);
5025 			bctl->flags |= BTRFS_BALANCE_RESUME;
5026 			spin_unlock(&fs_info->balance_lock);
5027 
5028 			goto do_balance;
5029 		}
5030 	} else {
5031 		bargs = NULL;
5032 	}
5033 
5034 	if (fs_info->balance_ctl) {
5035 		ret = -EINPROGRESS;
5036 		goto out_bargs;
5037 	}
5038 
5039 	bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
5040 	if (!bctl) {
5041 		ret = -ENOMEM;
5042 		goto out_bargs;
5043 	}
5044 
5045 	if (arg) {
5046 		memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
5047 		memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
5048 		memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
5049 
5050 		bctl->flags = bargs->flags;
5051 	} else {
5052 		/* balance everything - no filters */
5053 		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
5054 	}
5055 
5056 	if (bctl->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
5057 		ret = -EINVAL;
5058 		goto out_bctl;
5059 	}
5060 
5061 do_balance:
5062 	/*
5063 	 * Ownership of bctl and filesystem flag BTRFS_FS_EXCL_OP goes to
5064 	 * btrfs_balance.  bctl is freed in reset_balance_state, or, if
5065 	 * restriper was paused all the way until unmount, in free_fs_info.
5066 	 * The flag should be cleared after reset_balance_state.
5067 	 */
5068 	need_unlock = false;
5069 
5070 	ret = btrfs_balance(fs_info, bctl, bargs);
5071 	bctl = NULL;
5072 
5073 	if (arg) {
5074 		if (copy_to_user(arg, bargs, sizeof(*bargs)))
5075 			ret = -EFAULT;
5076 	}
5077 
5078 out_bctl:
5079 	kfree(bctl);
5080 out_bargs:
5081 	kfree(bargs);
5082 out_unlock:
5083 	mutex_unlock(&fs_info->balance_mutex);
5084 	if (need_unlock)
5085 		clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
5086 out:
5087 	mnt_drop_write_file(file);
5088 	return ret;
5089 }
5090 
5091 static long btrfs_ioctl_balance_ctl(struct btrfs_fs_info *fs_info, int cmd)
5092 {
5093 	if (!capable(CAP_SYS_ADMIN))
5094 		return -EPERM;
5095 
5096 	switch (cmd) {
5097 	case BTRFS_BALANCE_CTL_PAUSE:
5098 		return btrfs_pause_balance(fs_info);
5099 	case BTRFS_BALANCE_CTL_CANCEL:
5100 		return btrfs_cancel_balance(fs_info);
5101 	}
5102 
5103 	return -EINVAL;
5104 }
5105 
5106 static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
5107 					 void __user *arg)
5108 {
5109 	struct btrfs_ioctl_balance_args *bargs;
5110 	int ret = 0;
5111 
5112 	if (!capable(CAP_SYS_ADMIN))
5113 		return -EPERM;
5114 
5115 	mutex_lock(&fs_info->balance_mutex);
5116 	if (!fs_info->balance_ctl) {
5117 		ret = -ENOTCONN;
5118 		goto out;
5119 	}
5120 
5121 	bargs = kzalloc(sizeof(*bargs), GFP_KERNEL);
5122 	if (!bargs) {
5123 		ret = -ENOMEM;
5124 		goto out;
5125 	}
5126 
5127 	btrfs_update_ioctl_balance_args(fs_info, bargs);
5128 
5129 	if (copy_to_user(arg, bargs, sizeof(*bargs)))
5130 		ret = -EFAULT;
5131 
5132 	kfree(bargs);
5133 out:
5134 	mutex_unlock(&fs_info->balance_mutex);
5135 	return ret;
5136 }
5137 
5138 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
5139 {
5140 	struct inode *inode = file_inode(file);
5141 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5142 	struct btrfs_ioctl_quota_ctl_args *sa;
5143 	int ret;
5144 
5145 	if (!capable(CAP_SYS_ADMIN))
5146 		return -EPERM;
5147 
5148 	ret = mnt_want_write_file(file);
5149 	if (ret)
5150 		return ret;
5151 
5152 	sa = memdup_user(arg, sizeof(*sa));
5153 	if (IS_ERR(sa)) {
5154 		ret = PTR_ERR(sa);
5155 		goto drop_write;
5156 	}
5157 
5158 	down_write(&fs_info->subvol_sem);
5159 
5160 	switch (sa->cmd) {
5161 	case BTRFS_QUOTA_CTL_ENABLE:
5162 		ret = btrfs_quota_enable(fs_info);
5163 		break;
5164 	case BTRFS_QUOTA_CTL_DISABLE:
5165 		ret = btrfs_quota_disable(fs_info);
5166 		break;
5167 	default:
5168 		ret = -EINVAL;
5169 		break;
5170 	}
5171 
5172 	kfree(sa);
5173 	up_write(&fs_info->subvol_sem);
5174 drop_write:
5175 	mnt_drop_write_file(file);
5176 	return ret;
5177 }
5178 
5179 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
5180 {
5181 	struct inode *inode = file_inode(file);
5182 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5183 	struct btrfs_root *root = BTRFS_I(inode)->root;
5184 	struct btrfs_ioctl_qgroup_assign_args *sa;
5185 	struct btrfs_trans_handle *trans;
5186 	int ret;
5187 	int err;
5188 
5189 	if (!capable(CAP_SYS_ADMIN))
5190 		return -EPERM;
5191 
5192 	ret = mnt_want_write_file(file);
5193 	if (ret)
5194 		return ret;
5195 
5196 	sa = memdup_user(arg, sizeof(*sa));
5197 	if (IS_ERR(sa)) {
5198 		ret = PTR_ERR(sa);
5199 		goto drop_write;
5200 	}
5201 
5202 	trans = btrfs_join_transaction(root);
5203 	if (IS_ERR(trans)) {
5204 		ret = PTR_ERR(trans);
5205 		goto out;
5206 	}
5207 
5208 	if (sa->assign) {
5209 		ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst);
5210 	} else {
5211 		ret = btrfs_del_qgroup_relation(trans, sa->src, sa->dst);
5212 	}
5213 
5214 	/* update qgroup status and info */
5215 	err = btrfs_run_qgroups(trans);
5216 	if (err < 0)
5217 		btrfs_handle_fs_error(fs_info, err,
5218 				      "failed to update qgroup status and info");
5219 	err = btrfs_end_transaction(trans);
5220 	if (err && !ret)
5221 		ret = err;
5222 
5223 out:
5224 	kfree(sa);
5225 drop_write:
5226 	mnt_drop_write_file(file);
5227 	return ret;
5228 }
5229 
5230 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
5231 {
5232 	struct inode *inode = file_inode(file);
5233 	struct btrfs_root *root = BTRFS_I(inode)->root;
5234 	struct btrfs_ioctl_qgroup_create_args *sa;
5235 	struct btrfs_trans_handle *trans;
5236 	int ret;
5237 	int err;
5238 
5239 	if (!capable(CAP_SYS_ADMIN))
5240 		return -EPERM;
5241 
5242 	ret = mnt_want_write_file(file);
5243 	if (ret)
5244 		return ret;
5245 
5246 	sa = memdup_user(arg, sizeof(*sa));
5247 	if (IS_ERR(sa)) {
5248 		ret = PTR_ERR(sa);
5249 		goto drop_write;
5250 	}
5251 
5252 	if (!sa->qgroupid) {
5253 		ret = -EINVAL;
5254 		goto out;
5255 	}
5256 
5257 	trans = btrfs_join_transaction(root);
5258 	if (IS_ERR(trans)) {
5259 		ret = PTR_ERR(trans);
5260 		goto out;
5261 	}
5262 
5263 	if (sa->create) {
5264 		ret = btrfs_create_qgroup(trans, sa->qgroupid);
5265 	} else {
5266 		ret = btrfs_remove_qgroup(trans, sa->qgroupid);
5267 	}
5268 
5269 	err = btrfs_end_transaction(trans);
5270 	if (err && !ret)
5271 		ret = err;
5272 
5273 out:
5274 	kfree(sa);
5275 drop_write:
5276 	mnt_drop_write_file(file);
5277 	return ret;
5278 }
5279 
5280 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
5281 {
5282 	struct inode *inode = file_inode(file);
5283 	struct btrfs_root *root = BTRFS_I(inode)->root;
5284 	struct btrfs_ioctl_qgroup_limit_args *sa;
5285 	struct btrfs_trans_handle *trans;
5286 	int ret;
5287 	int err;
5288 	u64 qgroupid;
5289 
5290 	if (!capable(CAP_SYS_ADMIN))
5291 		return -EPERM;
5292 
5293 	ret = mnt_want_write_file(file);
5294 	if (ret)
5295 		return ret;
5296 
5297 	sa = memdup_user(arg, sizeof(*sa));
5298 	if (IS_ERR(sa)) {
5299 		ret = PTR_ERR(sa);
5300 		goto drop_write;
5301 	}
5302 
5303 	trans = btrfs_join_transaction(root);
5304 	if (IS_ERR(trans)) {
5305 		ret = PTR_ERR(trans);
5306 		goto out;
5307 	}
5308 
5309 	qgroupid = sa->qgroupid;
5310 	if (!qgroupid) {
5311 		/* take the current subvol as qgroup */
5312 		qgroupid = root->root_key.objectid;
5313 	}
5314 
5315 	ret = btrfs_limit_qgroup(trans, qgroupid, &sa->lim);
5316 
5317 	err = btrfs_end_transaction(trans);
5318 	if (err && !ret)
5319 		ret = err;
5320 
5321 out:
5322 	kfree(sa);
5323 drop_write:
5324 	mnt_drop_write_file(file);
5325 	return ret;
5326 }
5327 
5328 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
5329 {
5330 	struct inode *inode = file_inode(file);
5331 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5332 	struct btrfs_ioctl_quota_rescan_args *qsa;
5333 	int ret;
5334 
5335 	if (!capable(CAP_SYS_ADMIN))
5336 		return -EPERM;
5337 
5338 	ret = mnt_want_write_file(file);
5339 	if (ret)
5340 		return ret;
5341 
5342 	qsa = memdup_user(arg, sizeof(*qsa));
5343 	if (IS_ERR(qsa)) {
5344 		ret = PTR_ERR(qsa);
5345 		goto drop_write;
5346 	}
5347 
5348 	if (qsa->flags) {
5349 		ret = -EINVAL;
5350 		goto out;
5351 	}
5352 
5353 	ret = btrfs_qgroup_rescan(fs_info);
5354 
5355 out:
5356 	kfree(qsa);
5357 drop_write:
5358 	mnt_drop_write_file(file);
5359 	return ret;
5360 }
5361 
5362 static long btrfs_ioctl_quota_rescan_status(struct file *file, void __user *arg)
5363 {
5364 	struct inode *inode = file_inode(file);
5365 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5366 	struct btrfs_ioctl_quota_rescan_args *qsa;
5367 	int ret = 0;
5368 
5369 	if (!capable(CAP_SYS_ADMIN))
5370 		return -EPERM;
5371 
5372 	qsa = kzalloc(sizeof(*qsa), GFP_KERNEL);
5373 	if (!qsa)
5374 		return -ENOMEM;
5375 
5376 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
5377 		qsa->flags = 1;
5378 		qsa->progress = fs_info->qgroup_rescan_progress.objectid;
5379 	}
5380 
5381 	if (copy_to_user(arg, qsa, sizeof(*qsa)))
5382 		ret = -EFAULT;
5383 
5384 	kfree(qsa);
5385 	return ret;
5386 }
5387 
5388 static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg)
5389 {
5390 	struct inode *inode = file_inode(file);
5391 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5392 
5393 	if (!capable(CAP_SYS_ADMIN))
5394 		return -EPERM;
5395 
5396 	return btrfs_qgroup_wait_for_completion(fs_info, true);
5397 }
5398 
5399 static long _btrfs_ioctl_set_received_subvol(struct file *file,
5400 					    struct btrfs_ioctl_received_subvol_args *sa)
5401 {
5402 	struct inode *inode = file_inode(file);
5403 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5404 	struct btrfs_root *root = BTRFS_I(inode)->root;
5405 	struct btrfs_root_item *root_item = &root->root_item;
5406 	struct btrfs_trans_handle *trans;
5407 	struct timespec64 ct = current_time(inode);
5408 	int ret = 0;
5409 	int received_uuid_changed;
5410 
5411 	if (!inode_owner_or_capable(inode))
5412 		return -EPERM;
5413 
5414 	ret = mnt_want_write_file(file);
5415 	if (ret < 0)
5416 		return ret;
5417 
5418 	down_write(&fs_info->subvol_sem);
5419 
5420 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
5421 		ret = -EINVAL;
5422 		goto out;
5423 	}
5424 
5425 	if (btrfs_root_readonly(root)) {
5426 		ret = -EROFS;
5427 		goto out;
5428 	}
5429 
5430 	/*
5431 	 * 1 - root item
5432 	 * 2 - uuid items (received uuid + subvol uuid)
5433 	 */
5434 	trans = btrfs_start_transaction(root, 3);
5435 	if (IS_ERR(trans)) {
5436 		ret = PTR_ERR(trans);
5437 		trans = NULL;
5438 		goto out;
5439 	}
5440 
5441 	sa->rtransid = trans->transid;
5442 	sa->rtime.sec = ct.tv_sec;
5443 	sa->rtime.nsec = ct.tv_nsec;
5444 
5445 	received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
5446 				       BTRFS_UUID_SIZE);
5447 	if (received_uuid_changed &&
5448 	    !btrfs_is_empty_uuid(root_item->received_uuid)) {
5449 		ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid,
5450 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5451 					  root->root_key.objectid);
5452 		if (ret && ret != -ENOENT) {
5453 		        btrfs_abort_transaction(trans, ret);
5454 		        btrfs_end_transaction(trans);
5455 		        goto out;
5456 		}
5457 	}
5458 	memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
5459 	btrfs_set_root_stransid(root_item, sa->stransid);
5460 	btrfs_set_root_rtransid(root_item, sa->rtransid);
5461 	btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
5462 	btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
5463 	btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
5464 	btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
5465 
5466 	ret = btrfs_update_root(trans, fs_info->tree_root,
5467 				&root->root_key, &root->root_item);
5468 	if (ret < 0) {
5469 		btrfs_end_transaction(trans);
5470 		goto out;
5471 	}
5472 	if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
5473 		ret = btrfs_uuid_tree_add(trans, sa->uuid,
5474 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5475 					  root->root_key.objectid);
5476 		if (ret < 0 && ret != -EEXIST) {
5477 			btrfs_abort_transaction(trans, ret);
5478 			btrfs_end_transaction(trans);
5479 			goto out;
5480 		}
5481 	}
5482 	ret = btrfs_commit_transaction(trans);
5483 out:
5484 	up_write(&fs_info->subvol_sem);
5485 	mnt_drop_write_file(file);
5486 	return ret;
5487 }
5488 
5489 #ifdef CONFIG_64BIT
5490 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
5491 						void __user *arg)
5492 {
5493 	struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
5494 	struct btrfs_ioctl_received_subvol_args *args64 = NULL;
5495 	int ret = 0;
5496 
5497 	args32 = memdup_user(arg, sizeof(*args32));
5498 	if (IS_ERR(args32))
5499 		return PTR_ERR(args32);
5500 
5501 	args64 = kmalloc(sizeof(*args64), GFP_KERNEL);
5502 	if (!args64) {
5503 		ret = -ENOMEM;
5504 		goto out;
5505 	}
5506 
5507 	memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
5508 	args64->stransid = args32->stransid;
5509 	args64->rtransid = args32->rtransid;
5510 	args64->stime.sec = args32->stime.sec;
5511 	args64->stime.nsec = args32->stime.nsec;
5512 	args64->rtime.sec = args32->rtime.sec;
5513 	args64->rtime.nsec = args32->rtime.nsec;
5514 	args64->flags = args32->flags;
5515 
5516 	ret = _btrfs_ioctl_set_received_subvol(file, args64);
5517 	if (ret)
5518 		goto out;
5519 
5520 	memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
5521 	args32->stransid = args64->stransid;
5522 	args32->rtransid = args64->rtransid;
5523 	args32->stime.sec = args64->stime.sec;
5524 	args32->stime.nsec = args64->stime.nsec;
5525 	args32->rtime.sec = args64->rtime.sec;
5526 	args32->rtime.nsec = args64->rtime.nsec;
5527 	args32->flags = args64->flags;
5528 
5529 	ret = copy_to_user(arg, args32, sizeof(*args32));
5530 	if (ret)
5531 		ret = -EFAULT;
5532 
5533 out:
5534 	kfree(args32);
5535 	kfree(args64);
5536 	return ret;
5537 }
5538 #endif
5539 
5540 static long btrfs_ioctl_set_received_subvol(struct file *file,
5541 					    void __user *arg)
5542 {
5543 	struct btrfs_ioctl_received_subvol_args *sa = NULL;
5544 	int ret = 0;
5545 
5546 	sa = memdup_user(arg, sizeof(*sa));
5547 	if (IS_ERR(sa))
5548 		return PTR_ERR(sa);
5549 
5550 	ret = _btrfs_ioctl_set_received_subvol(file, sa);
5551 
5552 	if (ret)
5553 		goto out;
5554 
5555 	ret = copy_to_user(arg, sa, sizeof(*sa));
5556 	if (ret)
5557 		ret = -EFAULT;
5558 
5559 out:
5560 	kfree(sa);
5561 	return ret;
5562 }
5563 
5564 static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
5565 {
5566 	struct inode *inode = file_inode(file);
5567 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5568 	size_t len;
5569 	int ret;
5570 	char label[BTRFS_LABEL_SIZE];
5571 
5572 	spin_lock(&fs_info->super_lock);
5573 	memcpy(label, fs_info->super_copy->label, BTRFS_LABEL_SIZE);
5574 	spin_unlock(&fs_info->super_lock);
5575 
5576 	len = strnlen(label, BTRFS_LABEL_SIZE);
5577 
5578 	if (len == BTRFS_LABEL_SIZE) {
5579 		btrfs_warn(fs_info,
5580 			   "label is too long, return the first %zu bytes",
5581 			   --len);
5582 	}
5583 
5584 	ret = copy_to_user(arg, label, len);
5585 
5586 	return ret ? -EFAULT : 0;
5587 }
5588 
5589 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
5590 {
5591 	struct inode *inode = file_inode(file);
5592 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5593 	struct btrfs_root *root = BTRFS_I(inode)->root;
5594 	struct btrfs_super_block *super_block = fs_info->super_copy;
5595 	struct btrfs_trans_handle *trans;
5596 	char label[BTRFS_LABEL_SIZE];
5597 	int ret;
5598 
5599 	if (!capable(CAP_SYS_ADMIN))
5600 		return -EPERM;
5601 
5602 	if (copy_from_user(label, arg, sizeof(label)))
5603 		return -EFAULT;
5604 
5605 	if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
5606 		btrfs_err(fs_info,
5607 			  "unable to set label with more than %d bytes",
5608 			  BTRFS_LABEL_SIZE - 1);
5609 		return -EINVAL;
5610 	}
5611 
5612 	ret = mnt_want_write_file(file);
5613 	if (ret)
5614 		return ret;
5615 
5616 	trans = btrfs_start_transaction(root, 0);
5617 	if (IS_ERR(trans)) {
5618 		ret = PTR_ERR(trans);
5619 		goto out_unlock;
5620 	}
5621 
5622 	spin_lock(&fs_info->super_lock);
5623 	strcpy(super_block->label, label);
5624 	spin_unlock(&fs_info->super_lock);
5625 	ret = btrfs_commit_transaction(trans);
5626 
5627 out_unlock:
5628 	mnt_drop_write_file(file);
5629 	return ret;
5630 }
5631 
5632 #define INIT_FEATURE_FLAGS(suffix) \
5633 	{ .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
5634 	  .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
5635 	  .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
5636 
5637 int btrfs_ioctl_get_supported_features(void __user *arg)
5638 {
5639 	static const struct btrfs_ioctl_feature_flags features[3] = {
5640 		INIT_FEATURE_FLAGS(SUPP),
5641 		INIT_FEATURE_FLAGS(SAFE_SET),
5642 		INIT_FEATURE_FLAGS(SAFE_CLEAR)
5643 	};
5644 
5645 	if (copy_to_user(arg, &features, sizeof(features)))
5646 		return -EFAULT;
5647 
5648 	return 0;
5649 }
5650 
5651 static int btrfs_ioctl_get_features(struct file *file, void __user *arg)
5652 {
5653 	struct inode *inode = file_inode(file);
5654 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5655 	struct btrfs_super_block *super_block = fs_info->super_copy;
5656 	struct btrfs_ioctl_feature_flags features;
5657 
5658 	features.compat_flags = btrfs_super_compat_flags(super_block);
5659 	features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
5660 	features.incompat_flags = btrfs_super_incompat_flags(super_block);
5661 
5662 	if (copy_to_user(arg, &features, sizeof(features)))
5663 		return -EFAULT;
5664 
5665 	return 0;
5666 }
5667 
5668 static int check_feature_bits(struct btrfs_fs_info *fs_info,
5669 			      enum btrfs_feature_set set,
5670 			      u64 change_mask, u64 flags, u64 supported_flags,
5671 			      u64 safe_set, u64 safe_clear)
5672 {
5673 	const char *type = btrfs_feature_set_names[set];
5674 	char *names;
5675 	u64 disallowed, unsupported;
5676 	u64 set_mask = flags & change_mask;
5677 	u64 clear_mask = ~flags & change_mask;
5678 
5679 	unsupported = set_mask & ~supported_flags;
5680 	if (unsupported) {
5681 		names = btrfs_printable_features(set, unsupported);
5682 		if (names) {
5683 			btrfs_warn(fs_info,
5684 				   "this kernel does not support the %s feature bit%s",
5685 				   names, strchr(names, ',') ? "s" : "");
5686 			kfree(names);
5687 		} else
5688 			btrfs_warn(fs_info,
5689 				   "this kernel does not support %s bits 0x%llx",
5690 				   type, unsupported);
5691 		return -EOPNOTSUPP;
5692 	}
5693 
5694 	disallowed = set_mask & ~safe_set;
5695 	if (disallowed) {
5696 		names = btrfs_printable_features(set, disallowed);
5697 		if (names) {
5698 			btrfs_warn(fs_info,
5699 				   "can't set the %s feature bit%s while mounted",
5700 				   names, strchr(names, ',') ? "s" : "");
5701 			kfree(names);
5702 		} else
5703 			btrfs_warn(fs_info,
5704 				   "can't set %s bits 0x%llx while mounted",
5705 				   type, disallowed);
5706 		return -EPERM;
5707 	}
5708 
5709 	disallowed = clear_mask & ~safe_clear;
5710 	if (disallowed) {
5711 		names = btrfs_printable_features(set, disallowed);
5712 		if (names) {
5713 			btrfs_warn(fs_info,
5714 				   "can't clear the %s feature bit%s while mounted",
5715 				   names, strchr(names, ',') ? "s" : "");
5716 			kfree(names);
5717 		} else
5718 			btrfs_warn(fs_info,
5719 				   "can't clear %s bits 0x%llx while mounted",
5720 				   type, disallowed);
5721 		return -EPERM;
5722 	}
5723 
5724 	return 0;
5725 }
5726 
5727 #define check_feature(fs_info, change_mask, flags, mask_base)	\
5728 check_feature_bits(fs_info, FEAT_##mask_base, change_mask, flags,	\
5729 		   BTRFS_FEATURE_ ## mask_base ## _SUPP,	\
5730 		   BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,	\
5731 		   BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
5732 
5733 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
5734 {
5735 	struct inode *inode = file_inode(file);
5736 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5737 	struct btrfs_root *root = BTRFS_I(inode)->root;
5738 	struct btrfs_super_block *super_block = fs_info->super_copy;
5739 	struct btrfs_ioctl_feature_flags flags[2];
5740 	struct btrfs_trans_handle *trans;
5741 	u64 newflags;
5742 	int ret;
5743 
5744 	if (!capable(CAP_SYS_ADMIN))
5745 		return -EPERM;
5746 
5747 	if (copy_from_user(flags, arg, sizeof(flags)))
5748 		return -EFAULT;
5749 
5750 	/* Nothing to do */
5751 	if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
5752 	    !flags[0].incompat_flags)
5753 		return 0;
5754 
5755 	ret = check_feature(fs_info, flags[0].compat_flags,
5756 			    flags[1].compat_flags, COMPAT);
5757 	if (ret)
5758 		return ret;
5759 
5760 	ret = check_feature(fs_info, flags[0].compat_ro_flags,
5761 			    flags[1].compat_ro_flags, COMPAT_RO);
5762 	if (ret)
5763 		return ret;
5764 
5765 	ret = check_feature(fs_info, flags[0].incompat_flags,
5766 			    flags[1].incompat_flags, INCOMPAT);
5767 	if (ret)
5768 		return ret;
5769 
5770 	ret = mnt_want_write_file(file);
5771 	if (ret)
5772 		return ret;
5773 
5774 	trans = btrfs_start_transaction(root, 0);
5775 	if (IS_ERR(trans)) {
5776 		ret = PTR_ERR(trans);
5777 		goto out_drop_write;
5778 	}
5779 
5780 	spin_lock(&fs_info->super_lock);
5781 	newflags = btrfs_super_compat_flags(super_block);
5782 	newflags |= flags[0].compat_flags & flags[1].compat_flags;
5783 	newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
5784 	btrfs_set_super_compat_flags(super_block, newflags);
5785 
5786 	newflags = btrfs_super_compat_ro_flags(super_block);
5787 	newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
5788 	newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
5789 	btrfs_set_super_compat_ro_flags(super_block, newflags);
5790 
5791 	newflags = btrfs_super_incompat_flags(super_block);
5792 	newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
5793 	newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
5794 	btrfs_set_super_incompat_flags(super_block, newflags);
5795 	spin_unlock(&fs_info->super_lock);
5796 
5797 	ret = btrfs_commit_transaction(trans);
5798 out_drop_write:
5799 	mnt_drop_write_file(file);
5800 
5801 	return ret;
5802 }
5803 
5804 static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
5805 {
5806 	struct btrfs_ioctl_send_args *arg;
5807 	int ret;
5808 
5809 	if (compat) {
5810 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
5811 		struct btrfs_ioctl_send_args_32 args32;
5812 
5813 		ret = copy_from_user(&args32, argp, sizeof(args32));
5814 		if (ret)
5815 			return -EFAULT;
5816 		arg = kzalloc(sizeof(*arg), GFP_KERNEL);
5817 		if (!arg)
5818 			return -ENOMEM;
5819 		arg->send_fd = args32.send_fd;
5820 		arg->clone_sources_count = args32.clone_sources_count;
5821 		arg->clone_sources = compat_ptr(args32.clone_sources);
5822 		arg->parent_root = args32.parent_root;
5823 		arg->flags = args32.flags;
5824 		memcpy(arg->reserved, args32.reserved,
5825 		       sizeof(args32.reserved));
5826 #else
5827 		return -ENOTTY;
5828 #endif
5829 	} else {
5830 		arg = memdup_user(argp, sizeof(*arg));
5831 		if (IS_ERR(arg))
5832 			return PTR_ERR(arg);
5833 	}
5834 	ret = btrfs_ioctl_send(file, arg);
5835 	kfree(arg);
5836 	return ret;
5837 }
5838 
5839 long btrfs_ioctl(struct file *file, unsigned int
5840 		cmd, unsigned long arg)
5841 {
5842 	struct inode *inode = file_inode(file);
5843 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5844 	struct btrfs_root *root = BTRFS_I(inode)->root;
5845 	void __user *argp = (void __user *)arg;
5846 
5847 	switch (cmd) {
5848 	case FS_IOC_GETFLAGS:
5849 		return btrfs_ioctl_getflags(file, argp);
5850 	case FS_IOC_SETFLAGS:
5851 		return btrfs_ioctl_setflags(file, argp);
5852 	case FS_IOC_GETVERSION:
5853 		return btrfs_ioctl_getversion(file, argp);
5854 	case FITRIM:
5855 		return btrfs_ioctl_fitrim(file, argp);
5856 	case BTRFS_IOC_SNAP_CREATE:
5857 		return btrfs_ioctl_snap_create(file, argp, 0);
5858 	case BTRFS_IOC_SNAP_CREATE_V2:
5859 		return btrfs_ioctl_snap_create_v2(file, argp, 0);
5860 	case BTRFS_IOC_SUBVOL_CREATE:
5861 		return btrfs_ioctl_snap_create(file, argp, 1);
5862 	case BTRFS_IOC_SUBVOL_CREATE_V2:
5863 		return btrfs_ioctl_snap_create_v2(file, argp, 1);
5864 	case BTRFS_IOC_SNAP_DESTROY:
5865 		return btrfs_ioctl_snap_destroy(file, argp);
5866 	case BTRFS_IOC_SUBVOL_GETFLAGS:
5867 		return btrfs_ioctl_subvol_getflags(file, argp);
5868 	case BTRFS_IOC_SUBVOL_SETFLAGS:
5869 		return btrfs_ioctl_subvol_setflags(file, argp);
5870 	case BTRFS_IOC_DEFAULT_SUBVOL:
5871 		return btrfs_ioctl_default_subvol(file, argp);
5872 	case BTRFS_IOC_DEFRAG:
5873 		return btrfs_ioctl_defrag(file, NULL);
5874 	case BTRFS_IOC_DEFRAG_RANGE:
5875 		return btrfs_ioctl_defrag(file, argp);
5876 	case BTRFS_IOC_RESIZE:
5877 		return btrfs_ioctl_resize(file, argp);
5878 	case BTRFS_IOC_ADD_DEV:
5879 		return btrfs_ioctl_add_dev(fs_info, argp);
5880 	case BTRFS_IOC_RM_DEV:
5881 		return btrfs_ioctl_rm_dev(file, argp);
5882 	case BTRFS_IOC_RM_DEV_V2:
5883 		return btrfs_ioctl_rm_dev_v2(file, argp);
5884 	case BTRFS_IOC_FS_INFO:
5885 		return btrfs_ioctl_fs_info(fs_info, argp);
5886 	case BTRFS_IOC_DEV_INFO:
5887 		return btrfs_ioctl_dev_info(fs_info, argp);
5888 	case BTRFS_IOC_BALANCE:
5889 		return btrfs_ioctl_balance(file, NULL);
5890 	case BTRFS_IOC_TREE_SEARCH:
5891 		return btrfs_ioctl_tree_search(file, argp);
5892 	case BTRFS_IOC_TREE_SEARCH_V2:
5893 		return btrfs_ioctl_tree_search_v2(file, argp);
5894 	case BTRFS_IOC_INO_LOOKUP:
5895 		return btrfs_ioctl_ino_lookup(file, argp);
5896 	case BTRFS_IOC_INO_PATHS:
5897 		return btrfs_ioctl_ino_to_path(root, argp);
5898 	case BTRFS_IOC_LOGICAL_INO:
5899 		return btrfs_ioctl_logical_to_ino(fs_info, argp, 1);
5900 	case BTRFS_IOC_LOGICAL_INO_V2:
5901 		return btrfs_ioctl_logical_to_ino(fs_info, argp, 2);
5902 	case BTRFS_IOC_SPACE_INFO:
5903 		return btrfs_ioctl_space_info(fs_info, argp);
5904 	case BTRFS_IOC_SYNC: {
5905 		int ret;
5906 
5907 		ret = btrfs_start_delalloc_roots(fs_info, -1);
5908 		if (ret)
5909 			return ret;
5910 		ret = btrfs_sync_fs(inode->i_sb, 1);
5911 		/*
5912 		 * The transaction thread may want to do more work,
5913 		 * namely it pokes the cleaner kthread that will start
5914 		 * processing uncleaned subvols.
5915 		 */
5916 		wake_up_process(fs_info->transaction_kthread);
5917 		return ret;
5918 	}
5919 	case BTRFS_IOC_START_SYNC:
5920 		return btrfs_ioctl_start_sync(root, argp);
5921 	case BTRFS_IOC_WAIT_SYNC:
5922 		return btrfs_ioctl_wait_sync(fs_info, argp);
5923 	case BTRFS_IOC_SCRUB:
5924 		return btrfs_ioctl_scrub(file, argp);
5925 	case BTRFS_IOC_SCRUB_CANCEL:
5926 		return btrfs_ioctl_scrub_cancel(fs_info);
5927 	case BTRFS_IOC_SCRUB_PROGRESS:
5928 		return btrfs_ioctl_scrub_progress(fs_info, argp);
5929 	case BTRFS_IOC_BALANCE_V2:
5930 		return btrfs_ioctl_balance(file, argp);
5931 	case BTRFS_IOC_BALANCE_CTL:
5932 		return btrfs_ioctl_balance_ctl(fs_info, arg);
5933 	case BTRFS_IOC_BALANCE_PROGRESS:
5934 		return btrfs_ioctl_balance_progress(fs_info, argp);
5935 	case BTRFS_IOC_SET_RECEIVED_SUBVOL:
5936 		return btrfs_ioctl_set_received_subvol(file, argp);
5937 #ifdef CONFIG_64BIT
5938 	case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
5939 		return btrfs_ioctl_set_received_subvol_32(file, argp);
5940 #endif
5941 	case BTRFS_IOC_SEND:
5942 		return _btrfs_ioctl_send(file, argp, false);
5943 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
5944 	case BTRFS_IOC_SEND_32:
5945 		return _btrfs_ioctl_send(file, argp, true);
5946 #endif
5947 	case BTRFS_IOC_GET_DEV_STATS:
5948 		return btrfs_ioctl_get_dev_stats(fs_info, argp);
5949 	case BTRFS_IOC_QUOTA_CTL:
5950 		return btrfs_ioctl_quota_ctl(file, argp);
5951 	case BTRFS_IOC_QGROUP_ASSIGN:
5952 		return btrfs_ioctl_qgroup_assign(file, argp);
5953 	case BTRFS_IOC_QGROUP_CREATE:
5954 		return btrfs_ioctl_qgroup_create(file, argp);
5955 	case BTRFS_IOC_QGROUP_LIMIT:
5956 		return btrfs_ioctl_qgroup_limit(file, argp);
5957 	case BTRFS_IOC_QUOTA_RESCAN:
5958 		return btrfs_ioctl_quota_rescan(file, argp);
5959 	case BTRFS_IOC_QUOTA_RESCAN_STATUS:
5960 		return btrfs_ioctl_quota_rescan_status(file, argp);
5961 	case BTRFS_IOC_QUOTA_RESCAN_WAIT:
5962 		return btrfs_ioctl_quota_rescan_wait(file, argp);
5963 	case BTRFS_IOC_DEV_REPLACE:
5964 		return btrfs_ioctl_dev_replace(fs_info, argp);
5965 	case BTRFS_IOC_GET_FSLABEL:
5966 		return btrfs_ioctl_get_fslabel(file, argp);
5967 	case BTRFS_IOC_SET_FSLABEL:
5968 		return btrfs_ioctl_set_fslabel(file, argp);
5969 	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
5970 		return btrfs_ioctl_get_supported_features(argp);
5971 	case BTRFS_IOC_GET_FEATURES:
5972 		return btrfs_ioctl_get_features(file, argp);
5973 	case BTRFS_IOC_SET_FEATURES:
5974 		return btrfs_ioctl_set_features(file, argp);
5975 	case FS_IOC_FSGETXATTR:
5976 		return btrfs_ioctl_fsgetxattr(file, argp);
5977 	case FS_IOC_FSSETXATTR:
5978 		return btrfs_ioctl_fssetxattr(file, argp);
5979 	case BTRFS_IOC_GET_SUBVOL_INFO:
5980 		return btrfs_ioctl_get_subvol_info(file, argp);
5981 	case BTRFS_IOC_GET_SUBVOL_ROOTREF:
5982 		return btrfs_ioctl_get_subvol_rootref(file, argp);
5983 	case BTRFS_IOC_INO_LOOKUP_USER:
5984 		return btrfs_ioctl_ino_lookup_user(file, argp);
5985 	}
5986 
5987 	return -ENOTTY;
5988 }
5989 
5990 #ifdef CONFIG_COMPAT
5991 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5992 {
5993 	/*
5994 	 * These all access 32-bit values anyway so no further
5995 	 * handling is necessary.
5996 	 */
5997 	switch (cmd) {
5998 	case FS_IOC32_GETFLAGS:
5999 		cmd = FS_IOC_GETFLAGS;
6000 		break;
6001 	case FS_IOC32_SETFLAGS:
6002 		cmd = FS_IOC_SETFLAGS;
6003 		break;
6004 	case FS_IOC32_GETVERSION:
6005 		cmd = FS_IOC_GETVERSION;
6006 		break;
6007 	}
6008 
6009 	return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
6010 }
6011 #endif
6012