xref: /linux/fs/btrfs/ioctl.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 #include <linux/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
23 #include <linux/fs.h>
24 #include <linux/fsnotify.h>
25 #include <linux/pagemap.h>
26 #include <linux/highmem.h>
27 #include <linux/time.h>
28 #include <linux/init.h>
29 #include <linux/string.h>
30 #include <linux/backing-dev.h>
31 #include <linux/mount.h>
32 #include <linux/mpage.h>
33 #include <linux/namei.h>
34 #include <linux/swap.h>
35 #include <linux/writeback.h>
36 #include <linux/statfs.h>
37 #include <linux/compat.h>
38 #include <linux/bit_spinlock.h>
39 #include <linux/security.h>
40 #include <linux/xattr.h>
41 #include <linux/vmalloc.h>
42 #include <linux/slab.h>
43 #include <linux/blkdev.h>
44 #include <linux/uuid.h>
45 #include <linux/btrfs.h>
46 #include <linux/uaccess.h>
47 #include "ctree.h"
48 #include "disk-io.h"
49 #include "transaction.h"
50 #include "btrfs_inode.h"
51 #include "print-tree.h"
52 #include "volumes.h"
53 #include "locking.h"
54 #include "inode-map.h"
55 #include "backref.h"
56 #include "rcu-string.h"
57 #include "send.h"
58 #include "dev-replace.h"
59 #include "props.h"
60 #include "sysfs.h"
61 #include "qgroup.h"
62 
63 #ifdef CONFIG_64BIT
64 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
65  * structures are incorrect, as the timespec structure from userspace
66  * is 4 bytes too small. We define these alternatives here to teach
67  * the kernel about the 32-bit struct packing.
68  */
69 struct btrfs_ioctl_timespec_32 {
70 	__u64 sec;
71 	__u32 nsec;
72 } __attribute__ ((__packed__));
73 
74 struct btrfs_ioctl_received_subvol_args_32 {
75 	char	uuid[BTRFS_UUID_SIZE];	/* in */
76 	__u64	stransid;		/* in */
77 	__u64	rtransid;		/* out */
78 	struct btrfs_ioctl_timespec_32 stime; /* in */
79 	struct btrfs_ioctl_timespec_32 rtime; /* out */
80 	__u64	flags;			/* in */
81 	__u64	reserved[16];		/* in */
82 } __attribute__ ((__packed__));
83 
84 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
85 				struct btrfs_ioctl_received_subvol_args_32)
86 #endif
87 
88 
89 static int btrfs_clone(struct inode *src, struct inode *inode,
90 		       u64 off, u64 olen, u64 olen_aligned, u64 destoff,
91 		       int no_time_update);
92 
93 /* Mask out flags that are inappropriate for the given type of inode. */
94 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
95 {
96 	if (S_ISDIR(mode))
97 		return flags;
98 	else if (S_ISREG(mode))
99 		return flags & ~FS_DIRSYNC_FL;
100 	else
101 		return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
102 }
103 
104 /*
105  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
106  */
107 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
108 {
109 	unsigned int iflags = 0;
110 
111 	if (flags & BTRFS_INODE_SYNC)
112 		iflags |= FS_SYNC_FL;
113 	if (flags & BTRFS_INODE_IMMUTABLE)
114 		iflags |= FS_IMMUTABLE_FL;
115 	if (flags & BTRFS_INODE_APPEND)
116 		iflags |= FS_APPEND_FL;
117 	if (flags & BTRFS_INODE_NODUMP)
118 		iflags |= FS_NODUMP_FL;
119 	if (flags & BTRFS_INODE_NOATIME)
120 		iflags |= FS_NOATIME_FL;
121 	if (flags & BTRFS_INODE_DIRSYNC)
122 		iflags |= FS_DIRSYNC_FL;
123 	if (flags & BTRFS_INODE_NODATACOW)
124 		iflags |= FS_NOCOW_FL;
125 
126 	if ((flags & BTRFS_INODE_COMPRESS) && !(flags & BTRFS_INODE_NOCOMPRESS))
127 		iflags |= FS_COMPR_FL;
128 	else if (flags & BTRFS_INODE_NOCOMPRESS)
129 		iflags |= FS_NOCOMP_FL;
130 
131 	return iflags;
132 }
133 
134 /*
135  * Update inode->i_flags based on the btrfs internal flags.
136  */
137 void btrfs_update_iflags(struct inode *inode)
138 {
139 	struct btrfs_inode *ip = BTRFS_I(inode);
140 	unsigned int new_fl = 0;
141 
142 	if (ip->flags & BTRFS_INODE_SYNC)
143 		new_fl |= S_SYNC;
144 	if (ip->flags & BTRFS_INODE_IMMUTABLE)
145 		new_fl |= S_IMMUTABLE;
146 	if (ip->flags & BTRFS_INODE_APPEND)
147 		new_fl |= S_APPEND;
148 	if (ip->flags & BTRFS_INODE_NOATIME)
149 		new_fl |= S_NOATIME;
150 	if (ip->flags & BTRFS_INODE_DIRSYNC)
151 		new_fl |= S_DIRSYNC;
152 
153 	set_mask_bits(&inode->i_flags,
154 		      S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
155 		      new_fl);
156 }
157 
158 /*
159  * Inherit flags from the parent inode.
160  *
161  * Currently only the compression flags and the cow flags are inherited.
162  */
163 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
164 {
165 	unsigned int flags;
166 
167 	if (!dir)
168 		return;
169 
170 	flags = BTRFS_I(dir)->flags;
171 
172 	if (flags & BTRFS_INODE_NOCOMPRESS) {
173 		BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
174 		BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
175 	} else if (flags & BTRFS_INODE_COMPRESS) {
176 		BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
177 		BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
178 	}
179 
180 	if (flags & BTRFS_INODE_NODATACOW) {
181 		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
182 		if (S_ISREG(inode->i_mode))
183 			BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
184 	}
185 
186 	btrfs_update_iflags(inode);
187 }
188 
189 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
190 {
191 	struct btrfs_inode *ip = BTRFS_I(file_inode(file));
192 	unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
193 
194 	if (copy_to_user(arg, &flags, sizeof(flags)))
195 		return -EFAULT;
196 	return 0;
197 }
198 
199 static int check_flags(unsigned int flags)
200 {
201 	if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
202 		      FS_NOATIME_FL | FS_NODUMP_FL | \
203 		      FS_SYNC_FL | FS_DIRSYNC_FL | \
204 		      FS_NOCOMP_FL | FS_COMPR_FL |
205 		      FS_NOCOW_FL))
206 		return -EOPNOTSUPP;
207 
208 	if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
209 		return -EINVAL;
210 
211 	return 0;
212 }
213 
214 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
215 {
216 	struct inode *inode = file_inode(file);
217 	struct btrfs_inode *ip = BTRFS_I(inode);
218 	struct btrfs_root *root = ip->root;
219 	struct btrfs_trans_handle *trans;
220 	unsigned int flags, oldflags;
221 	int ret;
222 	u64 ip_oldflags;
223 	unsigned int i_oldflags;
224 	umode_t mode;
225 
226 	if (!inode_owner_or_capable(inode))
227 		return -EPERM;
228 
229 	if (btrfs_root_readonly(root))
230 		return -EROFS;
231 
232 	if (copy_from_user(&flags, arg, sizeof(flags)))
233 		return -EFAULT;
234 
235 	ret = check_flags(flags);
236 	if (ret)
237 		return ret;
238 
239 	ret = mnt_want_write_file(file);
240 	if (ret)
241 		return ret;
242 
243 	mutex_lock(&inode->i_mutex);
244 
245 	ip_oldflags = ip->flags;
246 	i_oldflags = inode->i_flags;
247 	mode = inode->i_mode;
248 
249 	flags = btrfs_mask_flags(inode->i_mode, flags);
250 	oldflags = btrfs_flags_to_ioctl(ip->flags);
251 	if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
252 		if (!capable(CAP_LINUX_IMMUTABLE)) {
253 			ret = -EPERM;
254 			goto out_unlock;
255 		}
256 	}
257 
258 	if (flags & FS_SYNC_FL)
259 		ip->flags |= BTRFS_INODE_SYNC;
260 	else
261 		ip->flags &= ~BTRFS_INODE_SYNC;
262 	if (flags & FS_IMMUTABLE_FL)
263 		ip->flags |= BTRFS_INODE_IMMUTABLE;
264 	else
265 		ip->flags &= ~BTRFS_INODE_IMMUTABLE;
266 	if (flags & FS_APPEND_FL)
267 		ip->flags |= BTRFS_INODE_APPEND;
268 	else
269 		ip->flags &= ~BTRFS_INODE_APPEND;
270 	if (flags & FS_NODUMP_FL)
271 		ip->flags |= BTRFS_INODE_NODUMP;
272 	else
273 		ip->flags &= ~BTRFS_INODE_NODUMP;
274 	if (flags & FS_NOATIME_FL)
275 		ip->flags |= BTRFS_INODE_NOATIME;
276 	else
277 		ip->flags &= ~BTRFS_INODE_NOATIME;
278 	if (flags & FS_DIRSYNC_FL)
279 		ip->flags |= BTRFS_INODE_DIRSYNC;
280 	else
281 		ip->flags &= ~BTRFS_INODE_DIRSYNC;
282 	if (flags & FS_NOCOW_FL) {
283 		if (S_ISREG(mode)) {
284 			/*
285 			 * It's safe to turn csums off here, no extents exist.
286 			 * Otherwise we want the flag to reflect the real COW
287 			 * status of the file and will not set it.
288 			 */
289 			if (inode->i_size == 0)
290 				ip->flags |= BTRFS_INODE_NODATACOW
291 					   | BTRFS_INODE_NODATASUM;
292 		} else {
293 			ip->flags |= BTRFS_INODE_NODATACOW;
294 		}
295 	} else {
296 		/*
297 		 * Revert back under same assuptions as above
298 		 */
299 		if (S_ISREG(mode)) {
300 			if (inode->i_size == 0)
301 				ip->flags &= ~(BTRFS_INODE_NODATACOW
302 				             | BTRFS_INODE_NODATASUM);
303 		} else {
304 			ip->flags &= ~BTRFS_INODE_NODATACOW;
305 		}
306 	}
307 
308 	/*
309 	 * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
310 	 * flag may be changed automatically if compression code won't make
311 	 * things smaller.
312 	 */
313 	if (flags & FS_NOCOMP_FL) {
314 		ip->flags &= ~BTRFS_INODE_COMPRESS;
315 		ip->flags |= BTRFS_INODE_NOCOMPRESS;
316 
317 		ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
318 		if (ret && ret != -ENODATA)
319 			goto out_drop;
320 	} else if (flags & FS_COMPR_FL) {
321 		const char *comp;
322 
323 		ip->flags |= BTRFS_INODE_COMPRESS;
324 		ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
325 
326 		if (root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
327 			comp = "lzo";
328 		else
329 			comp = "zlib";
330 		ret = btrfs_set_prop(inode, "btrfs.compression",
331 				     comp, strlen(comp), 0);
332 		if (ret)
333 			goto out_drop;
334 
335 	} else {
336 		ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
337 		if (ret && ret != -ENODATA)
338 			goto out_drop;
339 		ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
340 	}
341 
342 	trans = btrfs_start_transaction(root, 1);
343 	if (IS_ERR(trans)) {
344 		ret = PTR_ERR(trans);
345 		goto out_drop;
346 	}
347 
348 	btrfs_update_iflags(inode);
349 	inode_inc_iversion(inode);
350 	inode->i_ctime = CURRENT_TIME;
351 	ret = btrfs_update_inode(trans, root, inode);
352 
353 	btrfs_end_transaction(trans, root);
354  out_drop:
355 	if (ret) {
356 		ip->flags = ip_oldflags;
357 		inode->i_flags = i_oldflags;
358 	}
359 
360  out_unlock:
361 	mutex_unlock(&inode->i_mutex);
362 	mnt_drop_write_file(file);
363 	return ret;
364 }
365 
366 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
367 {
368 	struct inode *inode = file_inode(file);
369 
370 	return put_user(inode->i_generation, arg);
371 }
372 
373 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
374 {
375 	struct btrfs_fs_info *fs_info = btrfs_sb(file_inode(file)->i_sb);
376 	struct btrfs_device *device;
377 	struct request_queue *q;
378 	struct fstrim_range range;
379 	u64 minlen = ULLONG_MAX;
380 	u64 num_devices = 0;
381 	u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
382 	int ret;
383 
384 	if (!capable(CAP_SYS_ADMIN))
385 		return -EPERM;
386 
387 	rcu_read_lock();
388 	list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
389 				dev_list) {
390 		if (!device->bdev)
391 			continue;
392 		q = bdev_get_queue(device->bdev);
393 		if (blk_queue_discard(q)) {
394 			num_devices++;
395 			minlen = min((u64)q->limits.discard_granularity,
396 				     minlen);
397 		}
398 	}
399 	rcu_read_unlock();
400 
401 	if (!num_devices)
402 		return -EOPNOTSUPP;
403 	if (copy_from_user(&range, arg, sizeof(range)))
404 		return -EFAULT;
405 	if (range.start > total_bytes ||
406 	    range.len < fs_info->sb->s_blocksize)
407 		return -EINVAL;
408 
409 	range.len = min(range.len, total_bytes - range.start);
410 	range.minlen = max(range.minlen, minlen);
411 	ret = btrfs_trim_fs(fs_info->tree_root, &range);
412 	if (ret < 0)
413 		return ret;
414 
415 	if (copy_to_user(arg, &range, sizeof(range)))
416 		return -EFAULT;
417 
418 	return 0;
419 }
420 
421 int btrfs_is_empty_uuid(u8 *uuid)
422 {
423 	int i;
424 
425 	for (i = 0; i < BTRFS_UUID_SIZE; i++) {
426 		if (uuid[i])
427 			return 0;
428 	}
429 	return 1;
430 }
431 
432 static noinline int create_subvol(struct inode *dir,
433 				  struct dentry *dentry,
434 				  char *name, int namelen,
435 				  u64 *async_transid,
436 				  struct btrfs_qgroup_inherit *inherit)
437 {
438 	struct btrfs_trans_handle *trans;
439 	struct btrfs_key key;
440 	struct btrfs_root_item root_item;
441 	struct btrfs_inode_item *inode_item;
442 	struct extent_buffer *leaf;
443 	struct btrfs_root *root = BTRFS_I(dir)->root;
444 	struct btrfs_root *new_root;
445 	struct btrfs_block_rsv block_rsv;
446 	struct timespec cur_time = CURRENT_TIME;
447 	struct inode *inode;
448 	int ret;
449 	int err;
450 	u64 objectid;
451 	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
452 	u64 index = 0;
453 	u64 qgroup_reserved;
454 	uuid_le new_uuid;
455 
456 	ret = btrfs_find_free_objectid(root->fs_info->tree_root, &objectid);
457 	if (ret)
458 		return ret;
459 
460 	/*
461 	 * Don't create subvolume whose level is not zero. Or qgroup will be
462 	 * screwed up since it assume subvolme qgroup's level to be 0.
463 	 */
464 	if (btrfs_qgroup_level(objectid))
465 		return -ENOSPC;
466 
467 	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
468 	/*
469 	 * The same as the snapshot creation, please see the comment
470 	 * of create_snapshot().
471 	 */
472 	ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
473 					       8, &qgroup_reserved, false);
474 	if (ret)
475 		return ret;
476 
477 	trans = btrfs_start_transaction(root, 0);
478 	if (IS_ERR(trans)) {
479 		ret = PTR_ERR(trans);
480 		btrfs_subvolume_release_metadata(root, &block_rsv,
481 						 qgroup_reserved);
482 		return ret;
483 	}
484 	trans->block_rsv = &block_rsv;
485 	trans->bytes_reserved = block_rsv.size;
486 
487 	ret = btrfs_qgroup_inherit(trans, root->fs_info, 0, objectid, inherit);
488 	if (ret)
489 		goto fail;
490 
491 	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
492 	if (IS_ERR(leaf)) {
493 		ret = PTR_ERR(leaf);
494 		goto fail;
495 	}
496 
497 	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
498 	btrfs_set_header_bytenr(leaf, leaf->start);
499 	btrfs_set_header_generation(leaf, trans->transid);
500 	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
501 	btrfs_set_header_owner(leaf, objectid);
502 
503 	write_extent_buffer(leaf, root->fs_info->fsid, btrfs_header_fsid(),
504 			    BTRFS_FSID_SIZE);
505 	write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
506 			    btrfs_header_chunk_tree_uuid(leaf),
507 			    BTRFS_UUID_SIZE);
508 	btrfs_mark_buffer_dirty(leaf);
509 
510 	memset(&root_item, 0, sizeof(root_item));
511 
512 	inode_item = &root_item.inode;
513 	btrfs_set_stack_inode_generation(inode_item, 1);
514 	btrfs_set_stack_inode_size(inode_item, 3);
515 	btrfs_set_stack_inode_nlink(inode_item, 1);
516 	btrfs_set_stack_inode_nbytes(inode_item, root->nodesize);
517 	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
518 
519 	btrfs_set_root_flags(&root_item, 0);
520 	btrfs_set_root_limit(&root_item, 0);
521 	btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
522 
523 	btrfs_set_root_bytenr(&root_item, leaf->start);
524 	btrfs_set_root_generation(&root_item, trans->transid);
525 	btrfs_set_root_level(&root_item, 0);
526 	btrfs_set_root_refs(&root_item, 1);
527 	btrfs_set_root_used(&root_item, leaf->len);
528 	btrfs_set_root_last_snapshot(&root_item, 0);
529 
530 	btrfs_set_root_generation_v2(&root_item,
531 			btrfs_root_generation(&root_item));
532 	uuid_le_gen(&new_uuid);
533 	memcpy(root_item.uuid, new_uuid.b, BTRFS_UUID_SIZE);
534 	btrfs_set_stack_timespec_sec(&root_item.otime, cur_time.tv_sec);
535 	btrfs_set_stack_timespec_nsec(&root_item.otime, cur_time.tv_nsec);
536 	root_item.ctime = root_item.otime;
537 	btrfs_set_root_ctransid(&root_item, trans->transid);
538 	btrfs_set_root_otransid(&root_item, trans->transid);
539 
540 	btrfs_tree_unlock(leaf);
541 	free_extent_buffer(leaf);
542 	leaf = NULL;
543 
544 	btrfs_set_root_dirid(&root_item, new_dirid);
545 
546 	key.objectid = objectid;
547 	key.offset = 0;
548 	key.type = BTRFS_ROOT_ITEM_KEY;
549 	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
550 				&root_item);
551 	if (ret)
552 		goto fail;
553 
554 	key.offset = (u64)-1;
555 	new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
556 	if (IS_ERR(new_root)) {
557 		ret = PTR_ERR(new_root);
558 		btrfs_abort_transaction(trans, root, ret);
559 		goto fail;
560 	}
561 
562 	btrfs_record_root_in_trans(trans, new_root);
563 
564 	ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
565 	if (ret) {
566 		/* We potentially lose an unused inode item here */
567 		btrfs_abort_transaction(trans, root, ret);
568 		goto fail;
569 	}
570 
571 	/*
572 	 * insert the directory item
573 	 */
574 	ret = btrfs_set_inode_index(dir, &index);
575 	if (ret) {
576 		btrfs_abort_transaction(trans, root, ret);
577 		goto fail;
578 	}
579 
580 	ret = btrfs_insert_dir_item(trans, root,
581 				    name, namelen, dir, &key,
582 				    BTRFS_FT_DIR, index);
583 	if (ret) {
584 		btrfs_abort_transaction(trans, root, ret);
585 		goto fail;
586 	}
587 
588 	btrfs_i_size_write(dir, dir->i_size + namelen * 2);
589 	ret = btrfs_update_inode(trans, root, dir);
590 	BUG_ON(ret);
591 
592 	ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
593 				 objectid, root->root_key.objectid,
594 				 btrfs_ino(dir), index, name, namelen);
595 	BUG_ON(ret);
596 
597 	ret = btrfs_uuid_tree_add(trans, root->fs_info->uuid_root,
598 				  root_item.uuid, BTRFS_UUID_KEY_SUBVOL,
599 				  objectid);
600 	if (ret)
601 		btrfs_abort_transaction(trans, root, ret);
602 
603 fail:
604 	trans->block_rsv = NULL;
605 	trans->bytes_reserved = 0;
606 	btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
607 
608 	if (async_transid) {
609 		*async_transid = trans->transid;
610 		err = btrfs_commit_transaction_async(trans, root, 1);
611 		if (err)
612 			err = btrfs_commit_transaction(trans, root);
613 	} else {
614 		err = btrfs_commit_transaction(trans, root);
615 	}
616 	if (err && !ret)
617 		ret = err;
618 
619 	if (!ret) {
620 		inode = btrfs_lookup_dentry(dir, dentry);
621 		if (IS_ERR(inode))
622 			return PTR_ERR(inode);
623 		d_instantiate(dentry, inode);
624 	}
625 	return ret;
626 }
627 
628 static void btrfs_wait_for_no_snapshoting_writes(struct btrfs_root *root)
629 {
630 	s64 writers;
631 	DEFINE_WAIT(wait);
632 
633 	do {
634 		prepare_to_wait(&root->subv_writers->wait, &wait,
635 				TASK_UNINTERRUPTIBLE);
636 
637 		writers = percpu_counter_sum(&root->subv_writers->counter);
638 		if (writers)
639 			schedule();
640 
641 		finish_wait(&root->subv_writers->wait, &wait);
642 	} while (writers);
643 }
644 
645 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
646 			   struct dentry *dentry, char *name, int namelen,
647 			   u64 *async_transid, bool readonly,
648 			   struct btrfs_qgroup_inherit *inherit)
649 {
650 	struct inode *inode;
651 	struct btrfs_pending_snapshot *pending_snapshot;
652 	struct btrfs_trans_handle *trans;
653 	int ret;
654 
655 	if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
656 		return -EINVAL;
657 
658 	atomic_inc(&root->will_be_snapshoted);
659 	smp_mb__after_atomic();
660 	btrfs_wait_for_no_snapshoting_writes(root);
661 
662 	ret = btrfs_start_delalloc_inodes(root, 0);
663 	if (ret)
664 		goto out;
665 
666 	btrfs_wait_ordered_extents(root, -1);
667 
668 	pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
669 	if (!pending_snapshot) {
670 		ret = -ENOMEM;
671 		goto out;
672 	}
673 
674 	btrfs_init_block_rsv(&pending_snapshot->block_rsv,
675 			     BTRFS_BLOCK_RSV_TEMP);
676 	/*
677 	 * 1 - parent dir inode
678 	 * 2 - dir entries
679 	 * 1 - root item
680 	 * 2 - root ref/backref
681 	 * 1 - root of snapshot
682 	 * 1 - UUID item
683 	 */
684 	ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
685 					&pending_snapshot->block_rsv, 8,
686 					&pending_snapshot->qgroup_reserved,
687 					false);
688 	if (ret)
689 		goto free;
690 
691 	pending_snapshot->dentry = dentry;
692 	pending_snapshot->root = root;
693 	pending_snapshot->readonly = readonly;
694 	pending_snapshot->dir = dir;
695 	pending_snapshot->inherit = inherit;
696 
697 	trans = btrfs_start_transaction(root, 0);
698 	if (IS_ERR(trans)) {
699 		ret = PTR_ERR(trans);
700 		goto fail;
701 	}
702 
703 	spin_lock(&root->fs_info->trans_lock);
704 	list_add(&pending_snapshot->list,
705 		 &trans->transaction->pending_snapshots);
706 	spin_unlock(&root->fs_info->trans_lock);
707 	if (async_transid) {
708 		*async_transid = trans->transid;
709 		ret = btrfs_commit_transaction_async(trans,
710 				     root->fs_info->extent_root, 1);
711 		if (ret)
712 			ret = btrfs_commit_transaction(trans, root);
713 	} else {
714 		ret = btrfs_commit_transaction(trans,
715 					       root->fs_info->extent_root);
716 	}
717 	if (ret)
718 		goto fail;
719 
720 	ret = pending_snapshot->error;
721 	if (ret)
722 		goto fail;
723 
724 	ret = btrfs_orphan_cleanup(pending_snapshot->snap);
725 	if (ret)
726 		goto fail;
727 
728 	inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
729 	if (IS_ERR(inode)) {
730 		ret = PTR_ERR(inode);
731 		goto fail;
732 	}
733 
734 	d_instantiate(dentry, inode);
735 	ret = 0;
736 fail:
737 	btrfs_subvolume_release_metadata(BTRFS_I(dir)->root,
738 					 &pending_snapshot->block_rsv,
739 					 pending_snapshot->qgroup_reserved);
740 free:
741 	kfree(pending_snapshot);
742 out:
743 	if (atomic_dec_and_test(&root->will_be_snapshoted))
744 		wake_up_atomic_t(&root->will_be_snapshoted);
745 	return ret;
746 }
747 
748 /*  copy of may_delete in fs/namei.c()
749  *	Check whether we can remove a link victim from directory dir, check
750  *  whether the type of victim is right.
751  *  1. We can't do it if dir is read-only (done in permission())
752  *  2. We should have write and exec permissions on dir
753  *  3. We can't remove anything from append-only dir
754  *  4. We can't do anything with immutable dir (done in permission())
755  *  5. If the sticky bit on dir is set we should either
756  *	a. be owner of dir, or
757  *	b. be owner of victim, or
758  *	c. have CAP_FOWNER capability
759  *  6. If the victim is append-only or immutable we can't do antyhing with
760  *     links pointing to it.
761  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
762  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
763  *  9. We can't remove a root or mountpoint.
764  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
765  *     nfs_async_unlink().
766  */
767 
768 static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
769 {
770 	int error;
771 
772 	if (d_really_is_negative(victim))
773 		return -ENOENT;
774 
775 	BUG_ON(d_inode(victim->d_parent) != dir);
776 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
777 
778 	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
779 	if (error)
780 		return error;
781 	if (IS_APPEND(dir))
782 		return -EPERM;
783 	if (check_sticky(dir, d_inode(victim)) || IS_APPEND(d_inode(victim)) ||
784 	    IS_IMMUTABLE(d_inode(victim)) || IS_SWAPFILE(d_inode(victim)))
785 		return -EPERM;
786 	if (isdir) {
787 		if (!d_is_dir(victim))
788 			return -ENOTDIR;
789 		if (IS_ROOT(victim))
790 			return -EBUSY;
791 	} else if (d_is_dir(victim))
792 		return -EISDIR;
793 	if (IS_DEADDIR(dir))
794 		return -ENOENT;
795 	if (victim->d_flags & DCACHE_NFSFS_RENAMED)
796 		return -EBUSY;
797 	return 0;
798 }
799 
800 /* copy of may_create in fs/namei.c() */
801 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
802 {
803 	if (d_really_is_positive(child))
804 		return -EEXIST;
805 	if (IS_DEADDIR(dir))
806 		return -ENOENT;
807 	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
808 }
809 
810 /*
811  * Create a new subvolume below @parent.  This is largely modeled after
812  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
813  * inside this filesystem so it's quite a bit simpler.
814  */
815 static noinline int btrfs_mksubvol(struct path *parent,
816 				   char *name, int namelen,
817 				   struct btrfs_root *snap_src,
818 				   u64 *async_transid, bool readonly,
819 				   struct btrfs_qgroup_inherit *inherit)
820 {
821 	struct inode *dir  = d_inode(parent->dentry);
822 	struct dentry *dentry;
823 	int error;
824 
825 	error = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT);
826 	if (error == -EINTR)
827 		return error;
828 
829 	dentry = lookup_one_len(name, parent->dentry, namelen);
830 	error = PTR_ERR(dentry);
831 	if (IS_ERR(dentry))
832 		goto out_unlock;
833 
834 	error = -EEXIST;
835 	if (d_really_is_positive(dentry))
836 		goto out_dput;
837 
838 	error = btrfs_may_create(dir, dentry);
839 	if (error)
840 		goto out_dput;
841 
842 	/*
843 	 * even if this name doesn't exist, we may get hash collisions.
844 	 * check for them now when we can safely fail
845 	 */
846 	error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
847 					       dir->i_ino, name,
848 					       namelen);
849 	if (error)
850 		goto out_dput;
851 
852 	down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
853 
854 	if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
855 		goto out_up_read;
856 
857 	if (snap_src) {
858 		error = create_snapshot(snap_src, dir, dentry, name, namelen,
859 					async_transid, readonly, inherit);
860 	} else {
861 		error = create_subvol(dir, dentry, name, namelen,
862 				      async_transid, inherit);
863 	}
864 	if (!error)
865 		fsnotify_mkdir(dir, dentry);
866 out_up_read:
867 	up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
868 out_dput:
869 	dput(dentry);
870 out_unlock:
871 	mutex_unlock(&dir->i_mutex);
872 	return error;
873 }
874 
875 /*
876  * When we're defragging a range, we don't want to kick it off again
877  * if it is really just waiting for delalloc to send it down.
878  * If we find a nice big extent or delalloc range for the bytes in the
879  * file you want to defrag, we return 0 to let you know to skip this
880  * part of the file
881  */
882 static int check_defrag_in_cache(struct inode *inode, u64 offset, u32 thresh)
883 {
884 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
885 	struct extent_map *em = NULL;
886 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
887 	u64 end;
888 
889 	read_lock(&em_tree->lock);
890 	em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
891 	read_unlock(&em_tree->lock);
892 
893 	if (em) {
894 		end = extent_map_end(em);
895 		free_extent_map(em);
896 		if (end - offset > thresh)
897 			return 0;
898 	}
899 	/* if we already have a nice delalloc here, just stop */
900 	thresh /= 2;
901 	end = count_range_bits(io_tree, &offset, offset + thresh,
902 			       thresh, EXTENT_DELALLOC, 1);
903 	if (end >= thresh)
904 		return 0;
905 	return 1;
906 }
907 
908 /*
909  * helper function to walk through a file and find extents
910  * newer than a specific transid, and smaller than thresh.
911  *
912  * This is used by the defragging code to find new and small
913  * extents
914  */
915 static int find_new_extents(struct btrfs_root *root,
916 			    struct inode *inode, u64 newer_than,
917 			    u64 *off, u32 thresh)
918 {
919 	struct btrfs_path *path;
920 	struct btrfs_key min_key;
921 	struct extent_buffer *leaf;
922 	struct btrfs_file_extent_item *extent;
923 	int type;
924 	int ret;
925 	u64 ino = btrfs_ino(inode);
926 
927 	path = btrfs_alloc_path();
928 	if (!path)
929 		return -ENOMEM;
930 
931 	min_key.objectid = ino;
932 	min_key.type = BTRFS_EXTENT_DATA_KEY;
933 	min_key.offset = *off;
934 
935 	while (1) {
936 		ret = btrfs_search_forward(root, &min_key, path, newer_than);
937 		if (ret != 0)
938 			goto none;
939 process_slot:
940 		if (min_key.objectid != ino)
941 			goto none;
942 		if (min_key.type != BTRFS_EXTENT_DATA_KEY)
943 			goto none;
944 
945 		leaf = path->nodes[0];
946 		extent = btrfs_item_ptr(leaf, path->slots[0],
947 					struct btrfs_file_extent_item);
948 
949 		type = btrfs_file_extent_type(leaf, extent);
950 		if (type == BTRFS_FILE_EXTENT_REG &&
951 		    btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
952 		    check_defrag_in_cache(inode, min_key.offset, thresh)) {
953 			*off = min_key.offset;
954 			btrfs_free_path(path);
955 			return 0;
956 		}
957 
958 		path->slots[0]++;
959 		if (path->slots[0] < btrfs_header_nritems(leaf)) {
960 			btrfs_item_key_to_cpu(leaf, &min_key, path->slots[0]);
961 			goto process_slot;
962 		}
963 
964 		if (min_key.offset == (u64)-1)
965 			goto none;
966 
967 		min_key.offset++;
968 		btrfs_release_path(path);
969 	}
970 none:
971 	btrfs_free_path(path);
972 	return -ENOENT;
973 }
974 
975 static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start)
976 {
977 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
978 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
979 	struct extent_map *em;
980 	u64 len = PAGE_CACHE_SIZE;
981 
982 	/*
983 	 * hopefully we have this extent in the tree already, try without
984 	 * the full extent lock
985 	 */
986 	read_lock(&em_tree->lock);
987 	em = lookup_extent_mapping(em_tree, start, len);
988 	read_unlock(&em_tree->lock);
989 
990 	if (!em) {
991 		struct extent_state *cached = NULL;
992 		u64 end = start + len - 1;
993 
994 		/* get the big lock and read metadata off disk */
995 		lock_extent_bits(io_tree, start, end, 0, &cached);
996 		em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
997 		unlock_extent_cached(io_tree, start, end, &cached, GFP_NOFS);
998 
999 		if (IS_ERR(em))
1000 			return NULL;
1001 	}
1002 
1003 	return em;
1004 }
1005 
1006 static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
1007 {
1008 	struct extent_map *next;
1009 	bool ret = true;
1010 
1011 	/* this is the last extent */
1012 	if (em->start + em->len >= i_size_read(inode))
1013 		return false;
1014 
1015 	next = defrag_lookup_extent(inode, em->start + em->len);
1016 	if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
1017 		ret = false;
1018 	else if ((em->block_start + em->block_len == next->block_start) &&
1019 		 (em->block_len > 128 * 1024 && next->block_len > 128 * 1024))
1020 		ret = false;
1021 
1022 	free_extent_map(next);
1023 	return ret;
1024 }
1025 
1026 static int should_defrag_range(struct inode *inode, u64 start, u32 thresh,
1027 			       u64 *last_len, u64 *skip, u64 *defrag_end,
1028 			       int compress)
1029 {
1030 	struct extent_map *em;
1031 	int ret = 1;
1032 	bool next_mergeable = true;
1033 	bool prev_mergeable = true;
1034 
1035 	/*
1036 	 * make sure that once we start defragging an extent, we keep on
1037 	 * defragging it
1038 	 */
1039 	if (start < *defrag_end)
1040 		return 1;
1041 
1042 	*skip = 0;
1043 
1044 	em = defrag_lookup_extent(inode, start);
1045 	if (!em)
1046 		return 0;
1047 
1048 	/* this will cover holes, and inline extents */
1049 	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1050 		ret = 0;
1051 		goto out;
1052 	}
1053 
1054 	if (!*defrag_end)
1055 		prev_mergeable = false;
1056 
1057 	next_mergeable = defrag_check_next_extent(inode, em);
1058 	/*
1059 	 * we hit a real extent, if it is big or the next extent is not a
1060 	 * real extent, don't bother defragging it
1061 	 */
1062 	if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1063 	    (em->len >= thresh || (!next_mergeable && !prev_mergeable)))
1064 		ret = 0;
1065 out:
1066 	/*
1067 	 * last_len ends up being a counter of how many bytes we've defragged.
1068 	 * every time we choose not to defrag an extent, we reset *last_len
1069 	 * so that the next tiny extent will force a defrag.
1070 	 *
1071 	 * The end result of this is that tiny extents before a single big
1072 	 * extent will force at least part of that big extent to be defragged.
1073 	 */
1074 	if (ret) {
1075 		*defrag_end = extent_map_end(em);
1076 	} else {
1077 		*last_len = 0;
1078 		*skip = extent_map_end(em);
1079 		*defrag_end = 0;
1080 	}
1081 
1082 	free_extent_map(em);
1083 	return ret;
1084 }
1085 
1086 /*
1087  * it doesn't do much good to defrag one or two pages
1088  * at a time.  This pulls in a nice chunk of pages
1089  * to COW and defrag.
1090  *
1091  * It also makes sure the delalloc code has enough
1092  * dirty data to avoid making new small extents as part
1093  * of the defrag
1094  *
1095  * It's a good idea to start RA on this range
1096  * before calling this.
1097  */
1098 static int cluster_pages_for_defrag(struct inode *inode,
1099 				    struct page **pages,
1100 				    unsigned long start_index,
1101 				    unsigned long num_pages)
1102 {
1103 	unsigned long file_end;
1104 	u64 isize = i_size_read(inode);
1105 	u64 page_start;
1106 	u64 page_end;
1107 	u64 page_cnt;
1108 	int ret;
1109 	int i;
1110 	int i_done;
1111 	struct btrfs_ordered_extent *ordered;
1112 	struct extent_state *cached_state = NULL;
1113 	struct extent_io_tree *tree;
1114 	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1115 
1116 	file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
1117 	if (!isize || start_index > file_end)
1118 		return 0;
1119 
1120 	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1121 
1122 	ret = btrfs_delalloc_reserve_space(inode,
1123 					   page_cnt << PAGE_CACHE_SHIFT);
1124 	if (ret)
1125 		return ret;
1126 	i_done = 0;
1127 	tree = &BTRFS_I(inode)->io_tree;
1128 
1129 	/* step one, lock all the pages */
1130 	for (i = 0; i < page_cnt; i++) {
1131 		struct page *page;
1132 again:
1133 		page = find_or_create_page(inode->i_mapping,
1134 					   start_index + i, mask);
1135 		if (!page)
1136 			break;
1137 
1138 		page_start = page_offset(page);
1139 		page_end = page_start + PAGE_CACHE_SIZE - 1;
1140 		while (1) {
1141 			lock_extent_bits(tree, page_start, page_end,
1142 					 0, &cached_state);
1143 			ordered = btrfs_lookup_ordered_extent(inode,
1144 							      page_start);
1145 			unlock_extent_cached(tree, page_start, page_end,
1146 					     &cached_state, GFP_NOFS);
1147 			if (!ordered)
1148 				break;
1149 
1150 			unlock_page(page);
1151 			btrfs_start_ordered_extent(inode, ordered, 1);
1152 			btrfs_put_ordered_extent(ordered);
1153 			lock_page(page);
1154 			/*
1155 			 * we unlocked the page above, so we need check if
1156 			 * it was released or not.
1157 			 */
1158 			if (page->mapping != inode->i_mapping) {
1159 				unlock_page(page);
1160 				page_cache_release(page);
1161 				goto again;
1162 			}
1163 		}
1164 
1165 		if (!PageUptodate(page)) {
1166 			btrfs_readpage(NULL, page);
1167 			lock_page(page);
1168 			if (!PageUptodate(page)) {
1169 				unlock_page(page);
1170 				page_cache_release(page);
1171 				ret = -EIO;
1172 				break;
1173 			}
1174 		}
1175 
1176 		if (page->mapping != inode->i_mapping) {
1177 			unlock_page(page);
1178 			page_cache_release(page);
1179 			goto again;
1180 		}
1181 
1182 		pages[i] = page;
1183 		i_done++;
1184 	}
1185 	if (!i_done || ret)
1186 		goto out;
1187 
1188 	if (!(inode->i_sb->s_flags & MS_ACTIVE))
1189 		goto out;
1190 
1191 	/*
1192 	 * so now we have a nice long stream of locked
1193 	 * and up to date pages, lets wait on them
1194 	 */
1195 	for (i = 0; i < i_done; i++)
1196 		wait_on_page_writeback(pages[i]);
1197 
1198 	page_start = page_offset(pages[0]);
1199 	page_end = page_offset(pages[i_done - 1]) + PAGE_CACHE_SIZE;
1200 
1201 	lock_extent_bits(&BTRFS_I(inode)->io_tree,
1202 			 page_start, page_end - 1, 0, &cached_state);
1203 	clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1204 			  page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1205 			  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1206 			  &cached_state, GFP_NOFS);
1207 
1208 	if (i_done != page_cnt) {
1209 		spin_lock(&BTRFS_I(inode)->lock);
1210 		BTRFS_I(inode)->outstanding_extents++;
1211 		spin_unlock(&BTRFS_I(inode)->lock);
1212 		btrfs_delalloc_release_space(inode,
1213 				     (page_cnt - i_done) << PAGE_CACHE_SHIFT);
1214 	}
1215 
1216 
1217 	set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1218 			  &cached_state, GFP_NOFS);
1219 
1220 	unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1221 			     page_start, page_end - 1, &cached_state,
1222 			     GFP_NOFS);
1223 
1224 	for (i = 0; i < i_done; i++) {
1225 		clear_page_dirty_for_io(pages[i]);
1226 		ClearPageChecked(pages[i]);
1227 		set_page_extent_mapped(pages[i]);
1228 		set_page_dirty(pages[i]);
1229 		unlock_page(pages[i]);
1230 		page_cache_release(pages[i]);
1231 	}
1232 	return i_done;
1233 out:
1234 	for (i = 0; i < i_done; i++) {
1235 		unlock_page(pages[i]);
1236 		page_cache_release(pages[i]);
1237 	}
1238 	btrfs_delalloc_release_space(inode, page_cnt << PAGE_CACHE_SHIFT);
1239 	return ret;
1240 
1241 }
1242 
1243 int btrfs_defrag_file(struct inode *inode, struct file *file,
1244 		      struct btrfs_ioctl_defrag_range_args *range,
1245 		      u64 newer_than, unsigned long max_to_defrag)
1246 {
1247 	struct btrfs_root *root = BTRFS_I(inode)->root;
1248 	struct file_ra_state *ra = NULL;
1249 	unsigned long last_index;
1250 	u64 isize = i_size_read(inode);
1251 	u64 last_len = 0;
1252 	u64 skip = 0;
1253 	u64 defrag_end = 0;
1254 	u64 newer_off = range->start;
1255 	unsigned long i;
1256 	unsigned long ra_index = 0;
1257 	int ret;
1258 	int defrag_count = 0;
1259 	int compress_type = BTRFS_COMPRESS_ZLIB;
1260 	u32 extent_thresh = range->extent_thresh;
1261 	unsigned long max_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
1262 	unsigned long cluster = max_cluster;
1263 	u64 new_align = ~((u64)128 * 1024 - 1);
1264 	struct page **pages = NULL;
1265 
1266 	if (isize == 0)
1267 		return 0;
1268 
1269 	if (range->start >= isize)
1270 		return -EINVAL;
1271 
1272 	if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1273 		if (range->compress_type > BTRFS_COMPRESS_TYPES)
1274 			return -EINVAL;
1275 		if (range->compress_type)
1276 			compress_type = range->compress_type;
1277 	}
1278 
1279 	if (extent_thresh == 0)
1280 		extent_thresh = 256 * 1024;
1281 
1282 	/*
1283 	 * if we were not given a file, allocate a readahead
1284 	 * context
1285 	 */
1286 	if (!file) {
1287 		ra = kzalloc(sizeof(*ra), GFP_NOFS);
1288 		if (!ra)
1289 			return -ENOMEM;
1290 		file_ra_state_init(ra, inode->i_mapping);
1291 	} else {
1292 		ra = &file->f_ra;
1293 	}
1294 
1295 	pages = kmalloc_array(max_cluster, sizeof(struct page *),
1296 			GFP_NOFS);
1297 	if (!pages) {
1298 		ret = -ENOMEM;
1299 		goto out_ra;
1300 	}
1301 
1302 	/* find the last page to defrag */
1303 	if (range->start + range->len > range->start) {
1304 		last_index = min_t(u64, isize - 1,
1305 			 range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
1306 	} else {
1307 		last_index = (isize - 1) >> PAGE_CACHE_SHIFT;
1308 	}
1309 
1310 	if (newer_than) {
1311 		ret = find_new_extents(root, inode, newer_than,
1312 				       &newer_off, 64 * 1024);
1313 		if (!ret) {
1314 			range->start = newer_off;
1315 			/*
1316 			 * we always align our defrag to help keep
1317 			 * the extents in the file evenly spaced
1318 			 */
1319 			i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1320 		} else
1321 			goto out_ra;
1322 	} else {
1323 		i = range->start >> PAGE_CACHE_SHIFT;
1324 	}
1325 	if (!max_to_defrag)
1326 		max_to_defrag = last_index - i + 1;
1327 
1328 	/*
1329 	 * make writeback starts from i, so the defrag range can be
1330 	 * written sequentially.
1331 	 */
1332 	if (i < inode->i_mapping->writeback_index)
1333 		inode->i_mapping->writeback_index = i;
1334 
1335 	while (i <= last_index && defrag_count < max_to_defrag &&
1336 	       (i < DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE))) {
1337 		/*
1338 		 * make sure we stop running if someone unmounts
1339 		 * the FS
1340 		 */
1341 		if (!(inode->i_sb->s_flags & MS_ACTIVE))
1342 			break;
1343 
1344 		if (btrfs_defrag_cancelled(root->fs_info)) {
1345 			printk(KERN_DEBUG "BTRFS: defrag_file cancelled\n");
1346 			ret = -EAGAIN;
1347 			break;
1348 		}
1349 
1350 		if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
1351 					 extent_thresh, &last_len, &skip,
1352 					 &defrag_end, range->flags &
1353 					 BTRFS_DEFRAG_RANGE_COMPRESS)) {
1354 			unsigned long next;
1355 			/*
1356 			 * the should_defrag function tells us how much to skip
1357 			 * bump our counter by the suggested amount
1358 			 */
1359 			next = DIV_ROUND_UP(skip, PAGE_CACHE_SIZE);
1360 			i = max(i + 1, next);
1361 			continue;
1362 		}
1363 
1364 		if (!newer_than) {
1365 			cluster = (PAGE_CACHE_ALIGN(defrag_end) >>
1366 				   PAGE_CACHE_SHIFT) - i;
1367 			cluster = min(cluster, max_cluster);
1368 		} else {
1369 			cluster = max_cluster;
1370 		}
1371 
1372 		if (i + cluster > ra_index) {
1373 			ra_index = max(i, ra_index);
1374 			btrfs_force_ra(inode->i_mapping, ra, file, ra_index,
1375 				       cluster);
1376 			ra_index += cluster;
1377 		}
1378 
1379 		mutex_lock(&inode->i_mutex);
1380 		if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
1381 			BTRFS_I(inode)->force_compress = compress_type;
1382 		ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1383 		if (ret < 0) {
1384 			mutex_unlock(&inode->i_mutex);
1385 			goto out_ra;
1386 		}
1387 
1388 		defrag_count += ret;
1389 		balance_dirty_pages_ratelimited(inode->i_mapping);
1390 		mutex_unlock(&inode->i_mutex);
1391 
1392 		if (newer_than) {
1393 			if (newer_off == (u64)-1)
1394 				break;
1395 
1396 			if (ret > 0)
1397 				i += ret;
1398 
1399 			newer_off = max(newer_off + 1,
1400 					(u64)i << PAGE_CACHE_SHIFT);
1401 
1402 			ret = find_new_extents(root, inode,
1403 					       newer_than, &newer_off,
1404 					       64 * 1024);
1405 			if (!ret) {
1406 				range->start = newer_off;
1407 				i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1408 			} else {
1409 				break;
1410 			}
1411 		} else {
1412 			if (ret > 0) {
1413 				i += ret;
1414 				last_len += ret << PAGE_CACHE_SHIFT;
1415 			} else {
1416 				i++;
1417 				last_len = 0;
1418 			}
1419 		}
1420 	}
1421 
1422 	if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1423 		filemap_flush(inode->i_mapping);
1424 		if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1425 			     &BTRFS_I(inode)->runtime_flags))
1426 			filemap_flush(inode->i_mapping);
1427 	}
1428 
1429 	if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1430 		/* the filemap_flush will queue IO into the worker threads, but
1431 		 * we have to make sure the IO is actually started and that
1432 		 * ordered extents get created before we return
1433 		 */
1434 		atomic_inc(&root->fs_info->async_submit_draining);
1435 		while (atomic_read(&root->fs_info->nr_async_submits) ||
1436 		      atomic_read(&root->fs_info->async_delalloc_pages)) {
1437 			wait_event(root->fs_info->async_submit_wait,
1438 			   (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
1439 			    atomic_read(&root->fs_info->async_delalloc_pages) == 0));
1440 		}
1441 		atomic_dec(&root->fs_info->async_submit_draining);
1442 	}
1443 
1444 	if (range->compress_type == BTRFS_COMPRESS_LZO) {
1445 		btrfs_set_fs_incompat(root->fs_info, COMPRESS_LZO);
1446 	}
1447 
1448 	ret = defrag_count;
1449 
1450 out_ra:
1451 	if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1452 		mutex_lock(&inode->i_mutex);
1453 		BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
1454 		mutex_unlock(&inode->i_mutex);
1455 	}
1456 	if (!file)
1457 		kfree(ra);
1458 	kfree(pages);
1459 	return ret;
1460 }
1461 
1462 static noinline int btrfs_ioctl_resize(struct file *file,
1463 					void __user *arg)
1464 {
1465 	u64 new_size;
1466 	u64 old_size;
1467 	u64 devid = 1;
1468 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
1469 	struct btrfs_ioctl_vol_args *vol_args;
1470 	struct btrfs_trans_handle *trans;
1471 	struct btrfs_device *device = NULL;
1472 	char *sizestr;
1473 	char *retptr;
1474 	char *devstr = NULL;
1475 	int ret = 0;
1476 	int mod = 0;
1477 
1478 	if (!capable(CAP_SYS_ADMIN))
1479 		return -EPERM;
1480 
1481 	ret = mnt_want_write_file(file);
1482 	if (ret)
1483 		return ret;
1484 
1485 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1486 			1)) {
1487 		mnt_drop_write_file(file);
1488 		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1489 	}
1490 
1491 	mutex_lock(&root->fs_info->volume_mutex);
1492 	vol_args = memdup_user(arg, sizeof(*vol_args));
1493 	if (IS_ERR(vol_args)) {
1494 		ret = PTR_ERR(vol_args);
1495 		goto out;
1496 	}
1497 
1498 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1499 
1500 	sizestr = vol_args->name;
1501 	devstr = strchr(sizestr, ':');
1502 	if (devstr) {
1503 		sizestr = devstr + 1;
1504 		*devstr = '\0';
1505 		devstr = vol_args->name;
1506 		ret = kstrtoull(devstr, 10, &devid);
1507 		if (ret)
1508 			goto out_free;
1509 		if (!devid) {
1510 			ret = -EINVAL;
1511 			goto out_free;
1512 		}
1513 		btrfs_info(root->fs_info, "resizing devid %llu", devid);
1514 	}
1515 
1516 	device = btrfs_find_device(root->fs_info, devid, NULL, NULL);
1517 	if (!device) {
1518 		btrfs_info(root->fs_info, "resizer unable to find device %llu",
1519 		       devid);
1520 		ret = -ENODEV;
1521 		goto out_free;
1522 	}
1523 
1524 	if (!device->writeable) {
1525 		btrfs_info(root->fs_info,
1526 			   "resizer unable to apply on readonly device %llu",
1527 		       devid);
1528 		ret = -EPERM;
1529 		goto out_free;
1530 	}
1531 
1532 	if (!strcmp(sizestr, "max"))
1533 		new_size = device->bdev->bd_inode->i_size;
1534 	else {
1535 		if (sizestr[0] == '-') {
1536 			mod = -1;
1537 			sizestr++;
1538 		} else if (sizestr[0] == '+') {
1539 			mod = 1;
1540 			sizestr++;
1541 		}
1542 		new_size = memparse(sizestr, &retptr);
1543 		if (*retptr != '\0' || new_size == 0) {
1544 			ret = -EINVAL;
1545 			goto out_free;
1546 		}
1547 	}
1548 
1549 	if (device->is_tgtdev_for_dev_replace) {
1550 		ret = -EPERM;
1551 		goto out_free;
1552 	}
1553 
1554 	old_size = btrfs_device_get_total_bytes(device);
1555 
1556 	if (mod < 0) {
1557 		if (new_size > old_size) {
1558 			ret = -EINVAL;
1559 			goto out_free;
1560 		}
1561 		new_size = old_size - new_size;
1562 	} else if (mod > 0) {
1563 		if (new_size > ULLONG_MAX - old_size) {
1564 			ret = -ERANGE;
1565 			goto out_free;
1566 		}
1567 		new_size = old_size + new_size;
1568 	}
1569 
1570 	if (new_size < 256 * 1024 * 1024) {
1571 		ret = -EINVAL;
1572 		goto out_free;
1573 	}
1574 	if (new_size > device->bdev->bd_inode->i_size) {
1575 		ret = -EFBIG;
1576 		goto out_free;
1577 	}
1578 
1579 	new_size = div_u64(new_size, root->sectorsize);
1580 	new_size *= root->sectorsize;
1581 
1582 	printk_in_rcu(KERN_INFO "BTRFS: new size for %s is %llu\n",
1583 		      rcu_str_deref(device->name), new_size);
1584 
1585 	if (new_size > old_size) {
1586 		trans = btrfs_start_transaction(root, 0);
1587 		if (IS_ERR(trans)) {
1588 			ret = PTR_ERR(trans);
1589 			goto out_free;
1590 		}
1591 		ret = btrfs_grow_device(trans, device, new_size);
1592 		btrfs_commit_transaction(trans, root);
1593 	} else if (new_size < old_size) {
1594 		ret = btrfs_shrink_device(device, new_size);
1595 	} /* equal, nothing need to do */
1596 
1597 out_free:
1598 	kfree(vol_args);
1599 out:
1600 	mutex_unlock(&root->fs_info->volume_mutex);
1601 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
1602 	mnt_drop_write_file(file);
1603 	return ret;
1604 }
1605 
1606 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1607 				char *name, unsigned long fd, int subvol,
1608 				u64 *transid, bool readonly,
1609 				struct btrfs_qgroup_inherit *inherit)
1610 {
1611 	int namelen;
1612 	int ret = 0;
1613 
1614 	ret = mnt_want_write_file(file);
1615 	if (ret)
1616 		goto out;
1617 
1618 	namelen = strlen(name);
1619 	if (strchr(name, '/')) {
1620 		ret = -EINVAL;
1621 		goto out_drop_write;
1622 	}
1623 
1624 	if (name[0] == '.' &&
1625 	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1626 		ret = -EEXIST;
1627 		goto out_drop_write;
1628 	}
1629 
1630 	if (subvol) {
1631 		ret = btrfs_mksubvol(&file->f_path, name, namelen,
1632 				     NULL, transid, readonly, inherit);
1633 	} else {
1634 		struct fd src = fdget(fd);
1635 		struct inode *src_inode;
1636 		if (!src.file) {
1637 			ret = -EINVAL;
1638 			goto out_drop_write;
1639 		}
1640 
1641 		src_inode = file_inode(src.file);
1642 		if (src_inode->i_sb != file_inode(file)->i_sb) {
1643 			btrfs_info(BTRFS_I(src_inode)->root->fs_info,
1644 				   "Snapshot src from another FS");
1645 			ret = -EXDEV;
1646 		} else if (!inode_owner_or_capable(src_inode)) {
1647 			/*
1648 			 * Subvolume creation is not restricted, but snapshots
1649 			 * are limited to own subvolumes only
1650 			 */
1651 			ret = -EPERM;
1652 		} else {
1653 			ret = btrfs_mksubvol(&file->f_path, name, namelen,
1654 					     BTRFS_I(src_inode)->root,
1655 					     transid, readonly, inherit);
1656 		}
1657 		fdput(src);
1658 	}
1659 out_drop_write:
1660 	mnt_drop_write_file(file);
1661 out:
1662 	return ret;
1663 }
1664 
1665 static noinline int btrfs_ioctl_snap_create(struct file *file,
1666 					    void __user *arg, int subvol)
1667 {
1668 	struct btrfs_ioctl_vol_args *vol_args;
1669 	int ret;
1670 
1671 	vol_args = memdup_user(arg, sizeof(*vol_args));
1672 	if (IS_ERR(vol_args))
1673 		return PTR_ERR(vol_args);
1674 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1675 
1676 	ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1677 					      vol_args->fd, subvol,
1678 					      NULL, false, NULL);
1679 
1680 	kfree(vol_args);
1681 	return ret;
1682 }
1683 
1684 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1685 					       void __user *arg, int subvol)
1686 {
1687 	struct btrfs_ioctl_vol_args_v2 *vol_args;
1688 	int ret;
1689 	u64 transid = 0;
1690 	u64 *ptr = NULL;
1691 	bool readonly = false;
1692 	struct btrfs_qgroup_inherit *inherit = NULL;
1693 
1694 	vol_args = memdup_user(arg, sizeof(*vol_args));
1695 	if (IS_ERR(vol_args))
1696 		return PTR_ERR(vol_args);
1697 	vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1698 
1699 	if (vol_args->flags &
1700 	    ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
1701 	      BTRFS_SUBVOL_QGROUP_INHERIT)) {
1702 		ret = -EOPNOTSUPP;
1703 		goto free_args;
1704 	}
1705 
1706 	if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
1707 		ptr = &transid;
1708 	if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1709 		readonly = true;
1710 	if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1711 		if (vol_args->size > PAGE_CACHE_SIZE) {
1712 			ret = -EINVAL;
1713 			goto free_args;
1714 		}
1715 		inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1716 		if (IS_ERR(inherit)) {
1717 			ret = PTR_ERR(inherit);
1718 			goto free_args;
1719 		}
1720 	}
1721 
1722 	ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1723 					      vol_args->fd, subvol, ptr,
1724 					      readonly, inherit);
1725 	if (ret)
1726 		goto free_inherit;
1727 
1728 	if (ptr && copy_to_user(arg +
1729 				offsetof(struct btrfs_ioctl_vol_args_v2,
1730 					transid),
1731 				ptr, sizeof(*ptr)))
1732 		ret = -EFAULT;
1733 
1734 free_inherit:
1735 	kfree(inherit);
1736 free_args:
1737 	kfree(vol_args);
1738 	return ret;
1739 }
1740 
1741 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1742 						void __user *arg)
1743 {
1744 	struct inode *inode = file_inode(file);
1745 	struct btrfs_root *root = BTRFS_I(inode)->root;
1746 	int ret = 0;
1747 	u64 flags = 0;
1748 
1749 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID)
1750 		return -EINVAL;
1751 
1752 	down_read(&root->fs_info->subvol_sem);
1753 	if (btrfs_root_readonly(root))
1754 		flags |= BTRFS_SUBVOL_RDONLY;
1755 	up_read(&root->fs_info->subvol_sem);
1756 
1757 	if (copy_to_user(arg, &flags, sizeof(flags)))
1758 		ret = -EFAULT;
1759 
1760 	return ret;
1761 }
1762 
1763 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1764 					      void __user *arg)
1765 {
1766 	struct inode *inode = file_inode(file);
1767 	struct btrfs_root *root = BTRFS_I(inode)->root;
1768 	struct btrfs_trans_handle *trans;
1769 	u64 root_flags;
1770 	u64 flags;
1771 	int ret = 0;
1772 
1773 	if (!inode_owner_or_capable(inode))
1774 		return -EPERM;
1775 
1776 	ret = mnt_want_write_file(file);
1777 	if (ret)
1778 		goto out;
1779 
1780 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
1781 		ret = -EINVAL;
1782 		goto out_drop_write;
1783 	}
1784 
1785 	if (copy_from_user(&flags, arg, sizeof(flags))) {
1786 		ret = -EFAULT;
1787 		goto out_drop_write;
1788 	}
1789 
1790 	if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1791 		ret = -EINVAL;
1792 		goto out_drop_write;
1793 	}
1794 
1795 	if (flags & ~BTRFS_SUBVOL_RDONLY) {
1796 		ret = -EOPNOTSUPP;
1797 		goto out_drop_write;
1798 	}
1799 
1800 	down_write(&root->fs_info->subvol_sem);
1801 
1802 	/* nothing to do */
1803 	if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1804 		goto out_drop_sem;
1805 
1806 	root_flags = btrfs_root_flags(&root->root_item);
1807 	if (flags & BTRFS_SUBVOL_RDONLY) {
1808 		btrfs_set_root_flags(&root->root_item,
1809 				     root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1810 	} else {
1811 		/*
1812 		 * Block RO -> RW transition if this subvolume is involved in
1813 		 * send
1814 		 */
1815 		spin_lock(&root->root_item_lock);
1816 		if (root->send_in_progress == 0) {
1817 			btrfs_set_root_flags(&root->root_item,
1818 				     root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1819 			spin_unlock(&root->root_item_lock);
1820 		} else {
1821 			spin_unlock(&root->root_item_lock);
1822 			btrfs_warn(root->fs_info,
1823 			"Attempt to set subvolume %llu read-write during send",
1824 					root->root_key.objectid);
1825 			ret = -EPERM;
1826 			goto out_drop_sem;
1827 		}
1828 	}
1829 
1830 	trans = btrfs_start_transaction(root, 1);
1831 	if (IS_ERR(trans)) {
1832 		ret = PTR_ERR(trans);
1833 		goto out_reset;
1834 	}
1835 
1836 	ret = btrfs_update_root(trans, root->fs_info->tree_root,
1837 				&root->root_key, &root->root_item);
1838 
1839 	btrfs_commit_transaction(trans, root);
1840 out_reset:
1841 	if (ret)
1842 		btrfs_set_root_flags(&root->root_item, root_flags);
1843 out_drop_sem:
1844 	up_write(&root->fs_info->subvol_sem);
1845 out_drop_write:
1846 	mnt_drop_write_file(file);
1847 out:
1848 	return ret;
1849 }
1850 
1851 /*
1852  * helper to check if the subvolume references other subvolumes
1853  */
1854 static noinline int may_destroy_subvol(struct btrfs_root *root)
1855 {
1856 	struct btrfs_path *path;
1857 	struct btrfs_dir_item *di;
1858 	struct btrfs_key key;
1859 	u64 dir_id;
1860 	int ret;
1861 
1862 	path = btrfs_alloc_path();
1863 	if (!path)
1864 		return -ENOMEM;
1865 
1866 	/* Make sure this root isn't set as the default subvol */
1867 	dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
1868 	di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root, path,
1869 				   dir_id, "default", 7, 0);
1870 	if (di && !IS_ERR(di)) {
1871 		btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
1872 		if (key.objectid == root->root_key.objectid) {
1873 			ret = -EPERM;
1874 			btrfs_err(root->fs_info, "deleting default subvolume "
1875 				  "%llu is not allowed", key.objectid);
1876 			goto out;
1877 		}
1878 		btrfs_release_path(path);
1879 	}
1880 
1881 	key.objectid = root->root_key.objectid;
1882 	key.type = BTRFS_ROOT_REF_KEY;
1883 	key.offset = (u64)-1;
1884 
1885 	ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
1886 				&key, path, 0, 0);
1887 	if (ret < 0)
1888 		goto out;
1889 	BUG_ON(ret == 0);
1890 
1891 	ret = 0;
1892 	if (path->slots[0] > 0) {
1893 		path->slots[0]--;
1894 		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1895 		if (key.objectid == root->root_key.objectid &&
1896 		    key.type == BTRFS_ROOT_REF_KEY)
1897 			ret = -ENOTEMPTY;
1898 	}
1899 out:
1900 	btrfs_free_path(path);
1901 	return ret;
1902 }
1903 
1904 static noinline int key_in_sk(struct btrfs_key *key,
1905 			      struct btrfs_ioctl_search_key *sk)
1906 {
1907 	struct btrfs_key test;
1908 	int ret;
1909 
1910 	test.objectid = sk->min_objectid;
1911 	test.type = sk->min_type;
1912 	test.offset = sk->min_offset;
1913 
1914 	ret = btrfs_comp_cpu_keys(key, &test);
1915 	if (ret < 0)
1916 		return 0;
1917 
1918 	test.objectid = sk->max_objectid;
1919 	test.type = sk->max_type;
1920 	test.offset = sk->max_offset;
1921 
1922 	ret = btrfs_comp_cpu_keys(key, &test);
1923 	if (ret > 0)
1924 		return 0;
1925 	return 1;
1926 }
1927 
1928 static noinline int copy_to_sk(struct btrfs_root *root,
1929 			       struct btrfs_path *path,
1930 			       struct btrfs_key *key,
1931 			       struct btrfs_ioctl_search_key *sk,
1932 			       size_t *buf_size,
1933 			       char __user *ubuf,
1934 			       unsigned long *sk_offset,
1935 			       int *num_found)
1936 {
1937 	u64 found_transid;
1938 	struct extent_buffer *leaf;
1939 	struct btrfs_ioctl_search_header sh;
1940 	struct btrfs_key test;
1941 	unsigned long item_off;
1942 	unsigned long item_len;
1943 	int nritems;
1944 	int i;
1945 	int slot;
1946 	int ret = 0;
1947 
1948 	leaf = path->nodes[0];
1949 	slot = path->slots[0];
1950 	nritems = btrfs_header_nritems(leaf);
1951 
1952 	if (btrfs_header_generation(leaf) > sk->max_transid) {
1953 		i = nritems;
1954 		goto advance_key;
1955 	}
1956 	found_transid = btrfs_header_generation(leaf);
1957 
1958 	for (i = slot; i < nritems; i++) {
1959 		item_off = btrfs_item_ptr_offset(leaf, i);
1960 		item_len = btrfs_item_size_nr(leaf, i);
1961 
1962 		btrfs_item_key_to_cpu(leaf, key, i);
1963 		if (!key_in_sk(key, sk))
1964 			continue;
1965 
1966 		if (sizeof(sh) + item_len > *buf_size) {
1967 			if (*num_found) {
1968 				ret = 1;
1969 				goto out;
1970 			}
1971 
1972 			/*
1973 			 * return one empty item back for v1, which does not
1974 			 * handle -EOVERFLOW
1975 			 */
1976 
1977 			*buf_size = sizeof(sh) + item_len;
1978 			item_len = 0;
1979 			ret = -EOVERFLOW;
1980 		}
1981 
1982 		if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
1983 			ret = 1;
1984 			goto out;
1985 		}
1986 
1987 		sh.objectid = key->objectid;
1988 		sh.offset = key->offset;
1989 		sh.type = key->type;
1990 		sh.len = item_len;
1991 		sh.transid = found_transid;
1992 
1993 		/* copy search result header */
1994 		if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
1995 			ret = -EFAULT;
1996 			goto out;
1997 		}
1998 
1999 		*sk_offset += sizeof(sh);
2000 
2001 		if (item_len) {
2002 			char __user *up = ubuf + *sk_offset;
2003 			/* copy the item */
2004 			if (read_extent_buffer_to_user(leaf, up,
2005 						       item_off, item_len)) {
2006 				ret = -EFAULT;
2007 				goto out;
2008 			}
2009 
2010 			*sk_offset += item_len;
2011 		}
2012 		(*num_found)++;
2013 
2014 		if (ret) /* -EOVERFLOW from above */
2015 			goto out;
2016 
2017 		if (*num_found >= sk->nr_items) {
2018 			ret = 1;
2019 			goto out;
2020 		}
2021 	}
2022 advance_key:
2023 	ret = 0;
2024 	test.objectid = sk->max_objectid;
2025 	test.type = sk->max_type;
2026 	test.offset = sk->max_offset;
2027 	if (btrfs_comp_cpu_keys(key, &test) >= 0)
2028 		ret = 1;
2029 	else if (key->offset < (u64)-1)
2030 		key->offset++;
2031 	else if (key->type < (u8)-1) {
2032 		key->offset = 0;
2033 		key->type++;
2034 	} else if (key->objectid < (u64)-1) {
2035 		key->offset = 0;
2036 		key->type = 0;
2037 		key->objectid++;
2038 	} else
2039 		ret = 1;
2040 out:
2041 	/*
2042 	 *  0: all items from this leaf copied, continue with next
2043 	 *  1: * more items can be copied, but unused buffer is too small
2044 	 *     * all items were found
2045 	 *     Either way, it will stops the loop which iterates to the next
2046 	 *     leaf
2047 	 *  -EOVERFLOW: item was to large for buffer
2048 	 *  -EFAULT: could not copy extent buffer back to userspace
2049 	 */
2050 	return ret;
2051 }
2052 
2053 static noinline int search_ioctl(struct inode *inode,
2054 				 struct btrfs_ioctl_search_key *sk,
2055 				 size_t *buf_size,
2056 				 char __user *ubuf)
2057 {
2058 	struct btrfs_root *root;
2059 	struct btrfs_key key;
2060 	struct btrfs_path *path;
2061 	struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
2062 	int ret;
2063 	int num_found = 0;
2064 	unsigned long sk_offset = 0;
2065 
2066 	if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
2067 		*buf_size = sizeof(struct btrfs_ioctl_search_header);
2068 		return -EOVERFLOW;
2069 	}
2070 
2071 	path = btrfs_alloc_path();
2072 	if (!path)
2073 		return -ENOMEM;
2074 
2075 	if (sk->tree_id == 0) {
2076 		/* search the root of the inode that was passed */
2077 		root = BTRFS_I(inode)->root;
2078 	} else {
2079 		key.objectid = sk->tree_id;
2080 		key.type = BTRFS_ROOT_ITEM_KEY;
2081 		key.offset = (u64)-1;
2082 		root = btrfs_read_fs_root_no_name(info, &key);
2083 		if (IS_ERR(root)) {
2084 			printk(KERN_ERR "BTRFS: could not find root %llu\n",
2085 			       sk->tree_id);
2086 			btrfs_free_path(path);
2087 			return -ENOENT;
2088 		}
2089 	}
2090 
2091 	key.objectid = sk->min_objectid;
2092 	key.type = sk->min_type;
2093 	key.offset = sk->min_offset;
2094 
2095 	while (1) {
2096 		ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2097 		if (ret != 0) {
2098 			if (ret > 0)
2099 				ret = 0;
2100 			goto err;
2101 		}
2102 		ret = copy_to_sk(root, path, &key, sk, buf_size, ubuf,
2103 				 &sk_offset, &num_found);
2104 		btrfs_release_path(path);
2105 		if (ret)
2106 			break;
2107 
2108 	}
2109 	if (ret > 0)
2110 		ret = 0;
2111 err:
2112 	sk->nr_items = num_found;
2113 	btrfs_free_path(path);
2114 	return ret;
2115 }
2116 
2117 static noinline int btrfs_ioctl_tree_search(struct file *file,
2118 					   void __user *argp)
2119 {
2120 	struct btrfs_ioctl_search_args __user *uargs;
2121 	struct btrfs_ioctl_search_key sk;
2122 	struct inode *inode;
2123 	int ret;
2124 	size_t buf_size;
2125 
2126 	if (!capable(CAP_SYS_ADMIN))
2127 		return -EPERM;
2128 
2129 	uargs = (struct btrfs_ioctl_search_args __user *)argp;
2130 
2131 	if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
2132 		return -EFAULT;
2133 
2134 	buf_size = sizeof(uargs->buf);
2135 
2136 	inode = file_inode(file);
2137 	ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
2138 
2139 	/*
2140 	 * In the origin implementation an overflow is handled by returning a
2141 	 * search header with a len of zero, so reset ret.
2142 	 */
2143 	if (ret == -EOVERFLOW)
2144 		ret = 0;
2145 
2146 	if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
2147 		ret = -EFAULT;
2148 	return ret;
2149 }
2150 
2151 static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
2152 					       void __user *argp)
2153 {
2154 	struct btrfs_ioctl_search_args_v2 __user *uarg;
2155 	struct btrfs_ioctl_search_args_v2 args;
2156 	struct inode *inode;
2157 	int ret;
2158 	size_t buf_size;
2159 	const size_t buf_limit = 16 * 1024 * 1024;
2160 
2161 	if (!capable(CAP_SYS_ADMIN))
2162 		return -EPERM;
2163 
2164 	/* copy search header and buffer size */
2165 	uarg = (struct btrfs_ioctl_search_args_v2 __user *)argp;
2166 	if (copy_from_user(&args, uarg, sizeof(args)))
2167 		return -EFAULT;
2168 
2169 	buf_size = args.buf_size;
2170 
2171 	if (buf_size < sizeof(struct btrfs_ioctl_search_header))
2172 		return -EOVERFLOW;
2173 
2174 	/* limit result size to 16MB */
2175 	if (buf_size > buf_limit)
2176 		buf_size = buf_limit;
2177 
2178 	inode = file_inode(file);
2179 	ret = search_ioctl(inode, &args.key, &buf_size,
2180 			   (char *)(&uarg->buf[0]));
2181 	if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
2182 		ret = -EFAULT;
2183 	else if (ret == -EOVERFLOW &&
2184 		copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
2185 		ret = -EFAULT;
2186 
2187 	return ret;
2188 }
2189 
2190 /*
2191  * Search INODE_REFs to identify path name of 'dirid' directory
2192  * in a 'tree_id' tree. and sets path name to 'name'.
2193  */
2194 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2195 				u64 tree_id, u64 dirid, char *name)
2196 {
2197 	struct btrfs_root *root;
2198 	struct btrfs_key key;
2199 	char *ptr;
2200 	int ret = -1;
2201 	int slot;
2202 	int len;
2203 	int total_len = 0;
2204 	struct btrfs_inode_ref *iref;
2205 	struct extent_buffer *l;
2206 	struct btrfs_path *path;
2207 
2208 	if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2209 		name[0]='\0';
2210 		return 0;
2211 	}
2212 
2213 	path = btrfs_alloc_path();
2214 	if (!path)
2215 		return -ENOMEM;
2216 
2217 	ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
2218 
2219 	key.objectid = tree_id;
2220 	key.type = BTRFS_ROOT_ITEM_KEY;
2221 	key.offset = (u64)-1;
2222 	root = btrfs_read_fs_root_no_name(info, &key);
2223 	if (IS_ERR(root)) {
2224 		printk(KERN_ERR "BTRFS: could not find root %llu\n", tree_id);
2225 		ret = -ENOENT;
2226 		goto out;
2227 	}
2228 
2229 	key.objectid = dirid;
2230 	key.type = BTRFS_INODE_REF_KEY;
2231 	key.offset = (u64)-1;
2232 
2233 	while (1) {
2234 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2235 		if (ret < 0)
2236 			goto out;
2237 		else if (ret > 0) {
2238 			ret = btrfs_previous_item(root, path, dirid,
2239 						  BTRFS_INODE_REF_KEY);
2240 			if (ret < 0)
2241 				goto out;
2242 			else if (ret > 0) {
2243 				ret = -ENOENT;
2244 				goto out;
2245 			}
2246 		}
2247 
2248 		l = path->nodes[0];
2249 		slot = path->slots[0];
2250 		btrfs_item_key_to_cpu(l, &key, slot);
2251 
2252 		iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2253 		len = btrfs_inode_ref_name_len(l, iref);
2254 		ptr -= len + 1;
2255 		total_len += len + 1;
2256 		if (ptr < name) {
2257 			ret = -ENAMETOOLONG;
2258 			goto out;
2259 		}
2260 
2261 		*(ptr + len) = '/';
2262 		read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2263 
2264 		if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2265 			break;
2266 
2267 		btrfs_release_path(path);
2268 		key.objectid = key.offset;
2269 		key.offset = (u64)-1;
2270 		dirid = key.objectid;
2271 	}
2272 	memmove(name, ptr, total_len);
2273 	name[total_len] = '\0';
2274 	ret = 0;
2275 out:
2276 	btrfs_free_path(path);
2277 	return ret;
2278 }
2279 
2280 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2281 					   void __user *argp)
2282 {
2283 	 struct btrfs_ioctl_ino_lookup_args *args;
2284 	 struct inode *inode;
2285 	int ret = 0;
2286 
2287 	args = memdup_user(argp, sizeof(*args));
2288 	if (IS_ERR(args))
2289 		return PTR_ERR(args);
2290 
2291 	inode = file_inode(file);
2292 
2293 	/*
2294 	 * Unprivileged query to obtain the containing subvolume root id. The
2295 	 * path is reset so it's consistent with btrfs_search_path_in_tree.
2296 	 */
2297 	if (args->treeid == 0)
2298 		args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2299 
2300 	if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2301 		args->name[0] = 0;
2302 		goto out;
2303 	}
2304 
2305 	if (!capable(CAP_SYS_ADMIN)) {
2306 		ret = -EPERM;
2307 		goto out;
2308 	}
2309 
2310 	ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2311 					args->treeid, args->objectid,
2312 					args->name);
2313 
2314 out:
2315 	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2316 		ret = -EFAULT;
2317 
2318 	kfree(args);
2319 	return ret;
2320 }
2321 
2322 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2323 					     void __user *arg)
2324 {
2325 	struct dentry *parent = file->f_path.dentry;
2326 	struct dentry *dentry;
2327 	struct inode *dir = d_inode(parent);
2328 	struct inode *inode;
2329 	struct btrfs_root *root = BTRFS_I(dir)->root;
2330 	struct btrfs_root *dest = NULL;
2331 	struct btrfs_ioctl_vol_args *vol_args;
2332 	struct btrfs_trans_handle *trans;
2333 	struct btrfs_block_rsv block_rsv;
2334 	u64 root_flags;
2335 	u64 qgroup_reserved;
2336 	int namelen;
2337 	int ret;
2338 	int err = 0;
2339 
2340 	vol_args = memdup_user(arg, sizeof(*vol_args));
2341 	if (IS_ERR(vol_args))
2342 		return PTR_ERR(vol_args);
2343 
2344 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2345 	namelen = strlen(vol_args->name);
2346 	if (strchr(vol_args->name, '/') ||
2347 	    strncmp(vol_args->name, "..", namelen) == 0) {
2348 		err = -EINVAL;
2349 		goto out;
2350 	}
2351 
2352 	err = mnt_want_write_file(file);
2353 	if (err)
2354 		goto out;
2355 
2356 
2357 	err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT);
2358 	if (err == -EINTR)
2359 		goto out_drop_write;
2360 	dentry = lookup_one_len(vol_args->name, parent, namelen);
2361 	if (IS_ERR(dentry)) {
2362 		err = PTR_ERR(dentry);
2363 		goto out_unlock_dir;
2364 	}
2365 
2366 	if (d_really_is_negative(dentry)) {
2367 		err = -ENOENT;
2368 		goto out_dput;
2369 	}
2370 
2371 	inode = d_inode(dentry);
2372 	dest = BTRFS_I(inode)->root;
2373 	if (!capable(CAP_SYS_ADMIN)) {
2374 		/*
2375 		 * Regular user.  Only allow this with a special mount
2376 		 * option, when the user has write+exec access to the
2377 		 * subvol root, and when rmdir(2) would have been
2378 		 * allowed.
2379 		 *
2380 		 * Note that this is _not_ check that the subvol is
2381 		 * empty or doesn't contain data that we wouldn't
2382 		 * otherwise be able to delete.
2383 		 *
2384 		 * Users who want to delete empty subvols should try
2385 		 * rmdir(2).
2386 		 */
2387 		err = -EPERM;
2388 		if (!btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
2389 			goto out_dput;
2390 
2391 		/*
2392 		 * Do not allow deletion if the parent dir is the same
2393 		 * as the dir to be deleted.  That means the ioctl
2394 		 * must be called on the dentry referencing the root
2395 		 * of the subvol, not a random directory contained
2396 		 * within it.
2397 		 */
2398 		err = -EINVAL;
2399 		if (root == dest)
2400 			goto out_dput;
2401 
2402 		err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2403 		if (err)
2404 			goto out_dput;
2405 	}
2406 
2407 	/* check if subvolume may be deleted by a user */
2408 	err = btrfs_may_delete(dir, dentry, 1);
2409 	if (err)
2410 		goto out_dput;
2411 
2412 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
2413 		err = -EINVAL;
2414 		goto out_dput;
2415 	}
2416 
2417 	mutex_lock(&inode->i_mutex);
2418 
2419 	/*
2420 	 * Don't allow to delete a subvolume with send in progress. This is
2421 	 * inside the i_mutex so the error handling that has to drop the bit
2422 	 * again is not run concurrently.
2423 	 */
2424 	spin_lock(&dest->root_item_lock);
2425 	root_flags = btrfs_root_flags(&dest->root_item);
2426 	if (dest->send_in_progress == 0) {
2427 		btrfs_set_root_flags(&dest->root_item,
2428 				root_flags | BTRFS_ROOT_SUBVOL_DEAD);
2429 		spin_unlock(&dest->root_item_lock);
2430 	} else {
2431 		spin_unlock(&dest->root_item_lock);
2432 		btrfs_warn(root->fs_info,
2433 			"Attempt to delete subvolume %llu during send",
2434 			dest->root_key.objectid);
2435 		err = -EPERM;
2436 		goto out_unlock_inode;
2437 	}
2438 
2439 	down_write(&root->fs_info->subvol_sem);
2440 
2441 	err = may_destroy_subvol(dest);
2442 	if (err)
2443 		goto out_up_write;
2444 
2445 	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
2446 	/*
2447 	 * One for dir inode, two for dir entries, two for root
2448 	 * ref/backref.
2449 	 */
2450 	err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
2451 					       5, &qgroup_reserved, true);
2452 	if (err)
2453 		goto out_up_write;
2454 
2455 	trans = btrfs_start_transaction(root, 0);
2456 	if (IS_ERR(trans)) {
2457 		err = PTR_ERR(trans);
2458 		goto out_release;
2459 	}
2460 	trans->block_rsv = &block_rsv;
2461 	trans->bytes_reserved = block_rsv.size;
2462 
2463 	ret = btrfs_unlink_subvol(trans, root, dir,
2464 				dest->root_key.objectid,
2465 				dentry->d_name.name,
2466 				dentry->d_name.len);
2467 	if (ret) {
2468 		err = ret;
2469 		btrfs_abort_transaction(trans, root, ret);
2470 		goto out_end_trans;
2471 	}
2472 
2473 	btrfs_record_root_in_trans(trans, dest);
2474 
2475 	memset(&dest->root_item.drop_progress, 0,
2476 		sizeof(dest->root_item.drop_progress));
2477 	dest->root_item.drop_level = 0;
2478 	btrfs_set_root_refs(&dest->root_item, 0);
2479 
2480 	if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
2481 		ret = btrfs_insert_orphan_item(trans,
2482 					root->fs_info->tree_root,
2483 					dest->root_key.objectid);
2484 		if (ret) {
2485 			btrfs_abort_transaction(trans, root, ret);
2486 			err = ret;
2487 			goto out_end_trans;
2488 		}
2489 	}
2490 
2491 	ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
2492 				  dest->root_item.uuid, BTRFS_UUID_KEY_SUBVOL,
2493 				  dest->root_key.objectid);
2494 	if (ret && ret != -ENOENT) {
2495 		btrfs_abort_transaction(trans, root, ret);
2496 		err = ret;
2497 		goto out_end_trans;
2498 	}
2499 	if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
2500 		ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
2501 					  dest->root_item.received_uuid,
2502 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
2503 					  dest->root_key.objectid);
2504 		if (ret && ret != -ENOENT) {
2505 			btrfs_abort_transaction(trans, root, ret);
2506 			err = ret;
2507 			goto out_end_trans;
2508 		}
2509 	}
2510 
2511 out_end_trans:
2512 	trans->block_rsv = NULL;
2513 	trans->bytes_reserved = 0;
2514 	ret = btrfs_end_transaction(trans, root);
2515 	if (ret && !err)
2516 		err = ret;
2517 	inode->i_flags |= S_DEAD;
2518 out_release:
2519 	btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
2520 out_up_write:
2521 	up_write(&root->fs_info->subvol_sem);
2522 	if (err) {
2523 		spin_lock(&dest->root_item_lock);
2524 		root_flags = btrfs_root_flags(&dest->root_item);
2525 		btrfs_set_root_flags(&dest->root_item,
2526 				root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
2527 		spin_unlock(&dest->root_item_lock);
2528 	}
2529 out_unlock_inode:
2530 	mutex_unlock(&inode->i_mutex);
2531 	if (!err) {
2532 		d_invalidate(dentry);
2533 		btrfs_invalidate_inodes(dest);
2534 		d_delete(dentry);
2535 		ASSERT(dest->send_in_progress == 0);
2536 
2537 		/* the last ref */
2538 		if (dest->ino_cache_inode) {
2539 			iput(dest->ino_cache_inode);
2540 			dest->ino_cache_inode = NULL;
2541 		}
2542 	}
2543 out_dput:
2544 	dput(dentry);
2545 out_unlock_dir:
2546 	mutex_unlock(&dir->i_mutex);
2547 out_drop_write:
2548 	mnt_drop_write_file(file);
2549 out:
2550 	kfree(vol_args);
2551 	return err;
2552 }
2553 
2554 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2555 {
2556 	struct inode *inode = file_inode(file);
2557 	struct btrfs_root *root = BTRFS_I(inode)->root;
2558 	struct btrfs_ioctl_defrag_range_args *range;
2559 	int ret;
2560 
2561 	ret = mnt_want_write_file(file);
2562 	if (ret)
2563 		return ret;
2564 
2565 	if (btrfs_root_readonly(root)) {
2566 		ret = -EROFS;
2567 		goto out;
2568 	}
2569 
2570 	switch (inode->i_mode & S_IFMT) {
2571 	case S_IFDIR:
2572 		if (!capable(CAP_SYS_ADMIN)) {
2573 			ret = -EPERM;
2574 			goto out;
2575 		}
2576 		ret = btrfs_defrag_root(root);
2577 		if (ret)
2578 			goto out;
2579 		ret = btrfs_defrag_root(root->fs_info->extent_root);
2580 		break;
2581 	case S_IFREG:
2582 		if (!(file->f_mode & FMODE_WRITE)) {
2583 			ret = -EINVAL;
2584 			goto out;
2585 		}
2586 
2587 		range = kzalloc(sizeof(*range), GFP_KERNEL);
2588 		if (!range) {
2589 			ret = -ENOMEM;
2590 			goto out;
2591 		}
2592 
2593 		if (argp) {
2594 			if (copy_from_user(range, argp,
2595 					   sizeof(*range))) {
2596 				ret = -EFAULT;
2597 				kfree(range);
2598 				goto out;
2599 			}
2600 			/* compression requires us to start the IO */
2601 			if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2602 				range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
2603 				range->extent_thresh = (u32)-1;
2604 			}
2605 		} else {
2606 			/* the rest are all set to zero by kzalloc */
2607 			range->len = (u64)-1;
2608 		}
2609 		ret = btrfs_defrag_file(file_inode(file), file,
2610 					range, 0, 0);
2611 		if (ret > 0)
2612 			ret = 0;
2613 		kfree(range);
2614 		break;
2615 	default:
2616 		ret = -EINVAL;
2617 	}
2618 out:
2619 	mnt_drop_write_file(file);
2620 	return ret;
2621 }
2622 
2623 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
2624 {
2625 	struct btrfs_ioctl_vol_args *vol_args;
2626 	int ret;
2627 
2628 	if (!capable(CAP_SYS_ADMIN))
2629 		return -EPERM;
2630 
2631 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
2632 			1)) {
2633 		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2634 	}
2635 
2636 	mutex_lock(&root->fs_info->volume_mutex);
2637 	vol_args = memdup_user(arg, sizeof(*vol_args));
2638 	if (IS_ERR(vol_args)) {
2639 		ret = PTR_ERR(vol_args);
2640 		goto out;
2641 	}
2642 
2643 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2644 	ret = btrfs_init_new_device(root, vol_args->name);
2645 
2646 	if (!ret)
2647 		btrfs_info(root->fs_info, "disk added %s",vol_args->name);
2648 
2649 	kfree(vol_args);
2650 out:
2651 	mutex_unlock(&root->fs_info->volume_mutex);
2652 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
2653 	return ret;
2654 }
2655 
2656 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
2657 {
2658 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
2659 	struct btrfs_ioctl_vol_args *vol_args;
2660 	int ret;
2661 
2662 	if (!capable(CAP_SYS_ADMIN))
2663 		return -EPERM;
2664 
2665 	ret = mnt_want_write_file(file);
2666 	if (ret)
2667 		return ret;
2668 
2669 	vol_args = memdup_user(arg, sizeof(*vol_args));
2670 	if (IS_ERR(vol_args)) {
2671 		ret = PTR_ERR(vol_args);
2672 		goto err_drop;
2673 	}
2674 
2675 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2676 
2677 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
2678 			1)) {
2679 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2680 		goto out;
2681 	}
2682 
2683 	mutex_lock(&root->fs_info->volume_mutex);
2684 	ret = btrfs_rm_device(root, vol_args->name);
2685 	mutex_unlock(&root->fs_info->volume_mutex);
2686 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
2687 
2688 	if (!ret)
2689 		btrfs_info(root->fs_info, "disk deleted %s",vol_args->name);
2690 
2691 out:
2692 	kfree(vol_args);
2693 err_drop:
2694 	mnt_drop_write_file(file);
2695 	return ret;
2696 }
2697 
2698 static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
2699 {
2700 	struct btrfs_ioctl_fs_info_args *fi_args;
2701 	struct btrfs_device *device;
2702 	struct btrfs_device *next;
2703 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2704 	int ret = 0;
2705 
2706 	fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
2707 	if (!fi_args)
2708 		return -ENOMEM;
2709 
2710 	mutex_lock(&fs_devices->device_list_mutex);
2711 	fi_args->num_devices = fs_devices->num_devices;
2712 	memcpy(&fi_args->fsid, root->fs_info->fsid, sizeof(fi_args->fsid));
2713 
2714 	list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
2715 		if (device->devid > fi_args->max_id)
2716 			fi_args->max_id = device->devid;
2717 	}
2718 	mutex_unlock(&fs_devices->device_list_mutex);
2719 
2720 	fi_args->nodesize = root->fs_info->super_copy->nodesize;
2721 	fi_args->sectorsize = root->fs_info->super_copy->sectorsize;
2722 	fi_args->clone_alignment = root->fs_info->super_copy->sectorsize;
2723 
2724 	if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
2725 		ret = -EFAULT;
2726 
2727 	kfree(fi_args);
2728 	return ret;
2729 }
2730 
2731 static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg)
2732 {
2733 	struct btrfs_ioctl_dev_info_args *di_args;
2734 	struct btrfs_device *dev;
2735 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2736 	int ret = 0;
2737 	char *s_uuid = NULL;
2738 
2739 	di_args = memdup_user(arg, sizeof(*di_args));
2740 	if (IS_ERR(di_args))
2741 		return PTR_ERR(di_args);
2742 
2743 	if (!btrfs_is_empty_uuid(di_args->uuid))
2744 		s_uuid = di_args->uuid;
2745 
2746 	mutex_lock(&fs_devices->device_list_mutex);
2747 	dev = btrfs_find_device(root->fs_info, di_args->devid, s_uuid, NULL);
2748 
2749 	if (!dev) {
2750 		ret = -ENODEV;
2751 		goto out;
2752 	}
2753 
2754 	di_args->devid = dev->devid;
2755 	di_args->bytes_used = btrfs_device_get_bytes_used(dev);
2756 	di_args->total_bytes = btrfs_device_get_total_bytes(dev);
2757 	memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2758 	if (dev->name) {
2759 		struct rcu_string *name;
2760 
2761 		rcu_read_lock();
2762 		name = rcu_dereference(dev->name);
2763 		strncpy(di_args->path, name->str, sizeof(di_args->path));
2764 		rcu_read_unlock();
2765 		di_args->path[sizeof(di_args->path) - 1] = 0;
2766 	} else {
2767 		di_args->path[0] = '\0';
2768 	}
2769 
2770 out:
2771 	mutex_unlock(&fs_devices->device_list_mutex);
2772 	if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2773 		ret = -EFAULT;
2774 
2775 	kfree(di_args);
2776 	return ret;
2777 }
2778 
2779 static struct page *extent_same_get_page(struct inode *inode, pgoff_t index)
2780 {
2781 	struct page *page;
2782 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2783 
2784 	page = grab_cache_page(inode->i_mapping, index);
2785 	if (!page)
2786 		return NULL;
2787 
2788 	if (!PageUptodate(page)) {
2789 		if (extent_read_full_page_nolock(tree, page, btrfs_get_extent,
2790 						 0))
2791 			return NULL;
2792 		lock_page(page);
2793 		if (!PageUptodate(page)) {
2794 			unlock_page(page);
2795 			page_cache_release(page);
2796 			return NULL;
2797 		}
2798 	}
2799 	unlock_page(page);
2800 
2801 	return page;
2802 }
2803 
2804 static int gather_extent_pages(struct inode *inode, struct page **pages,
2805 			       int num_pages, u64 off)
2806 {
2807 	int i;
2808 	pgoff_t index = off >> PAGE_CACHE_SHIFT;
2809 
2810 	for (i = 0; i < num_pages; i++) {
2811 		pages[i] = extent_same_get_page(inode, index + i);
2812 		if (!pages[i])
2813 			return -ENOMEM;
2814 	}
2815 	return 0;
2816 }
2817 
2818 static inline void lock_extent_range(struct inode *inode, u64 off, u64 len)
2819 {
2820 	/* do any pending delalloc/csum calc on src, one way or
2821 	   another, and lock file content */
2822 	while (1) {
2823 		struct btrfs_ordered_extent *ordered;
2824 		lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2825 		ordered = btrfs_lookup_first_ordered_extent(inode,
2826 							    off + len - 1);
2827 		if ((!ordered ||
2828 		     ordered->file_offset + ordered->len <= off ||
2829 		     ordered->file_offset >= off + len) &&
2830 		    !test_range_bit(&BTRFS_I(inode)->io_tree, off,
2831 				    off + len - 1, EXTENT_DELALLOC, 0, NULL)) {
2832 			if (ordered)
2833 				btrfs_put_ordered_extent(ordered);
2834 			break;
2835 		}
2836 		unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2837 		if (ordered)
2838 			btrfs_put_ordered_extent(ordered);
2839 		btrfs_wait_ordered_range(inode, off, len);
2840 	}
2841 }
2842 
2843 static void btrfs_double_inode_unlock(struct inode *inode1, struct inode *inode2)
2844 {
2845 	mutex_unlock(&inode1->i_mutex);
2846 	mutex_unlock(&inode2->i_mutex);
2847 }
2848 
2849 static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
2850 {
2851 	if (inode1 < inode2)
2852 		swap(inode1, inode2);
2853 
2854 	mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
2855 	mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
2856 }
2857 
2858 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
2859 				      struct inode *inode2, u64 loff2, u64 len)
2860 {
2861 	unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
2862 	unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
2863 }
2864 
2865 static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
2866 				     struct inode *inode2, u64 loff2, u64 len)
2867 {
2868 	if (inode1 < inode2) {
2869 		swap(inode1, inode2);
2870 		swap(loff1, loff2);
2871 	}
2872 	lock_extent_range(inode1, loff1, len);
2873 	lock_extent_range(inode2, loff2, len);
2874 }
2875 
2876 struct cmp_pages {
2877 	int		num_pages;
2878 	struct page	**src_pages;
2879 	struct page	**dst_pages;
2880 };
2881 
2882 static void btrfs_cmp_data_free(struct cmp_pages *cmp)
2883 {
2884 	int i;
2885 	struct page *pg;
2886 
2887 	for (i = 0; i < cmp->num_pages; i++) {
2888 		pg = cmp->src_pages[i];
2889 		if (pg)
2890 			page_cache_release(pg);
2891 		pg = cmp->dst_pages[i];
2892 		if (pg)
2893 			page_cache_release(pg);
2894 	}
2895 	kfree(cmp->src_pages);
2896 	kfree(cmp->dst_pages);
2897 }
2898 
2899 static int btrfs_cmp_data_prepare(struct inode *src, u64 loff,
2900 				  struct inode *dst, u64 dst_loff,
2901 				  u64 len, struct cmp_pages *cmp)
2902 {
2903 	int ret;
2904 	int num_pages = PAGE_CACHE_ALIGN(len) >> PAGE_CACHE_SHIFT;
2905 	struct page **src_pgarr, **dst_pgarr;
2906 
2907 	/*
2908 	 * We must gather up all the pages before we initiate our
2909 	 * extent locking. We use an array for the page pointers. Size
2910 	 * of the array is bounded by len, which is in turn bounded by
2911 	 * BTRFS_MAX_DEDUPE_LEN.
2912 	 */
2913 	src_pgarr = kzalloc(num_pages * sizeof(struct page *), GFP_NOFS);
2914 	dst_pgarr = kzalloc(num_pages * sizeof(struct page *), GFP_NOFS);
2915 	if (!src_pgarr || !dst_pgarr) {
2916 		kfree(src_pgarr);
2917 		kfree(dst_pgarr);
2918 		return -ENOMEM;
2919 	}
2920 	cmp->num_pages = num_pages;
2921 	cmp->src_pages = src_pgarr;
2922 	cmp->dst_pages = dst_pgarr;
2923 
2924 	ret = gather_extent_pages(src, cmp->src_pages, cmp->num_pages, loff);
2925 	if (ret)
2926 		goto out;
2927 
2928 	ret = gather_extent_pages(dst, cmp->dst_pages, cmp->num_pages, dst_loff);
2929 
2930 out:
2931 	if (ret)
2932 		btrfs_cmp_data_free(cmp);
2933 	return 0;
2934 }
2935 
2936 static int btrfs_cmp_data(struct inode *src, u64 loff, struct inode *dst,
2937 			  u64 dst_loff, u64 len, struct cmp_pages *cmp)
2938 {
2939 	int ret = 0;
2940 	int i;
2941 	struct page *src_page, *dst_page;
2942 	unsigned int cmp_len = PAGE_CACHE_SIZE;
2943 	void *addr, *dst_addr;
2944 
2945 	i = 0;
2946 	while (len) {
2947 		if (len < PAGE_CACHE_SIZE)
2948 			cmp_len = len;
2949 
2950 		BUG_ON(i >= cmp->num_pages);
2951 
2952 		src_page = cmp->src_pages[i];
2953 		dst_page = cmp->dst_pages[i];
2954 
2955 		addr = kmap_atomic(src_page);
2956 		dst_addr = kmap_atomic(dst_page);
2957 
2958 		flush_dcache_page(src_page);
2959 		flush_dcache_page(dst_page);
2960 
2961 		if (memcmp(addr, dst_addr, cmp_len))
2962 			ret = BTRFS_SAME_DATA_DIFFERS;
2963 
2964 		kunmap_atomic(addr);
2965 		kunmap_atomic(dst_addr);
2966 
2967 		if (ret)
2968 			break;
2969 
2970 		len -= cmp_len;
2971 		i++;
2972 	}
2973 
2974 	return ret;
2975 }
2976 
2977 static int extent_same_check_offsets(struct inode *inode, u64 off, u64 *plen,
2978 				     u64 olen)
2979 {
2980 	u64 len = *plen;
2981 	u64 bs = BTRFS_I(inode)->root->fs_info->sb->s_blocksize;
2982 
2983 	if (off + olen > inode->i_size || off + olen < off)
2984 		return -EINVAL;
2985 
2986 	/* if we extend to eof, continue to block boundary */
2987 	if (off + len == inode->i_size)
2988 		*plen = len = ALIGN(inode->i_size, bs) - off;
2989 
2990 	/* Check that we are block aligned - btrfs_clone() requires this */
2991 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs))
2992 		return -EINVAL;
2993 
2994 	return 0;
2995 }
2996 
2997 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
2998 			     struct inode *dst, u64 dst_loff)
2999 {
3000 	int ret;
3001 	u64 len = olen;
3002 	struct cmp_pages cmp;
3003 	int same_inode = 0;
3004 	u64 same_lock_start = 0;
3005 	u64 same_lock_len = 0;
3006 
3007 	if (src == dst)
3008 		same_inode = 1;
3009 
3010 	if (len == 0)
3011 		return 0;
3012 
3013 	if (same_inode) {
3014 		mutex_lock(&src->i_mutex);
3015 
3016 		ret = extent_same_check_offsets(src, loff, &len, olen);
3017 		if (ret)
3018 			goto out_unlock;
3019 
3020 		/*
3021 		 * Single inode case wants the same checks, except we
3022 		 * don't want our length pushed out past i_size as
3023 		 * comparing that data range makes no sense.
3024 		 *
3025 		 * extent_same_check_offsets() will do this for an
3026 		 * unaligned length at i_size, so catch it here and
3027 		 * reject the request.
3028 		 *
3029 		 * This effectively means we require aligned extents
3030 		 * for the single-inode case, whereas the other cases
3031 		 * allow an unaligned length so long as it ends at
3032 		 * i_size.
3033 		 */
3034 		if (len != olen) {
3035 			ret = -EINVAL;
3036 			goto out_unlock;
3037 		}
3038 
3039 		/* Check for overlapping ranges */
3040 		if (dst_loff + len > loff && dst_loff < loff + len) {
3041 			ret = -EINVAL;
3042 			goto out_unlock;
3043 		}
3044 
3045 		same_lock_start = min_t(u64, loff, dst_loff);
3046 		same_lock_len = max_t(u64, loff, dst_loff) + len - same_lock_start;
3047 	} else {
3048 		btrfs_double_inode_lock(src, dst);
3049 
3050 		ret = extent_same_check_offsets(src, loff, &len, olen);
3051 		if (ret)
3052 			goto out_unlock;
3053 
3054 		ret = extent_same_check_offsets(dst, dst_loff, &len, olen);
3055 		if (ret)
3056 			goto out_unlock;
3057 	}
3058 
3059 	/* don't make the dst file partly checksummed */
3060 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3061 	    (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
3062 		ret = -EINVAL;
3063 		goto out_unlock;
3064 	}
3065 
3066 	ret = btrfs_cmp_data_prepare(src, loff, dst, dst_loff, olen, &cmp);
3067 	if (ret)
3068 		goto out_unlock;
3069 
3070 	if (same_inode)
3071 		lock_extent_range(src, same_lock_start, same_lock_len);
3072 	else
3073 		btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
3074 
3075 	/* pass original length for comparison so we stay within i_size */
3076 	ret = btrfs_cmp_data(src, loff, dst, dst_loff, olen, &cmp);
3077 	if (ret == 0)
3078 		ret = btrfs_clone(src, dst, loff, olen, len, dst_loff, 1);
3079 
3080 	if (same_inode)
3081 		unlock_extent(&BTRFS_I(src)->io_tree, same_lock_start,
3082 			      same_lock_start + same_lock_len - 1);
3083 	else
3084 		btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
3085 
3086 	btrfs_cmp_data_free(&cmp);
3087 out_unlock:
3088 	if (same_inode)
3089 		mutex_unlock(&src->i_mutex);
3090 	else
3091 		btrfs_double_inode_unlock(src, dst);
3092 
3093 	return ret;
3094 }
3095 
3096 #define BTRFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
3097 
3098 static long btrfs_ioctl_file_extent_same(struct file *file,
3099 			struct btrfs_ioctl_same_args __user *argp)
3100 {
3101 	struct btrfs_ioctl_same_args *same = NULL;
3102 	struct btrfs_ioctl_same_extent_info *info;
3103 	struct inode *src = file_inode(file);
3104 	u64 off;
3105 	u64 len;
3106 	int i;
3107 	int ret;
3108 	unsigned long size;
3109 	u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
3110 	bool is_admin = capable(CAP_SYS_ADMIN);
3111 	u16 count;
3112 
3113 	if (!(file->f_mode & FMODE_READ))
3114 		return -EINVAL;
3115 
3116 	ret = mnt_want_write_file(file);
3117 	if (ret)
3118 		return ret;
3119 
3120 	if (get_user(count, &argp->dest_count)) {
3121 		ret = -EFAULT;
3122 		goto out;
3123 	}
3124 
3125 	size = offsetof(struct btrfs_ioctl_same_args __user, info[count]);
3126 
3127 	same = memdup_user(argp, size);
3128 
3129 	if (IS_ERR(same)) {
3130 		ret = PTR_ERR(same);
3131 		same = NULL;
3132 		goto out;
3133 	}
3134 
3135 	off = same->logical_offset;
3136 	len = same->length;
3137 
3138 	/*
3139 	 * Limit the total length we will dedupe for each operation.
3140 	 * This is intended to bound the total time spent in this
3141 	 * ioctl to something sane.
3142 	 */
3143 	if (len > BTRFS_MAX_DEDUPE_LEN)
3144 		len = BTRFS_MAX_DEDUPE_LEN;
3145 
3146 	if (WARN_ON_ONCE(bs < PAGE_CACHE_SIZE)) {
3147 		/*
3148 		 * Btrfs does not support blocksize < page_size. As a
3149 		 * result, btrfs_cmp_data() won't correctly handle
3150 		 * this situation without an update.
3151 		 */
3152 		ret = -EINVAL;
3153 		goto out;
3154 	}
3155 
3156 	ret = -EISDIR;
3157 	if (S_ISDIR(src->i_mode))
3158 		goto out;
3159 
3160 	ret = -EACCES;
3161 	if (!S_ISREG(src->i_mode))
3162 		goto out;
3163 
3164 	/* pre-format output fields to sane values */
3165 	for (i = 0; i < count; i++) {
3166 		same->info[i].bytes_deduped = 0ULL;
3167 		same->info[i].status = 0;
3168 	}
3169 
3170 	for (i = 0, info = same->info; i < count; i++, info++) {
3171 		struct inode *dst;
3172 		struct fd dst_file = fdget(info->fd);
3173 		if (!dst_file.file) {
3174 			info->status = -EBADF;
3175 			continue;
3176 		}
3177 		dst = file_inode(dst_file.file);
3178 
3179 		if (!(is_admin || (dst_file.file->f_mode & FMODE_WRITE))) {
3180 			info->status = -EINVAL;
3181 		} else if (file->f_path.mnt != dst_file.file->f_path.mnt) {
3182 			info->status = -EXDEV;
3183 		} else if (S_ISDIR(dst->i_mode)) {
3184 			info->status = -EISDIR;
3185 		} else if (!S_ISREG(dst->i_mode)) {
3186 			info->status = -EACCES;
3187 		} else {
3188 			info->status = btrfs_extent_same(src, off, len, dst,
3189 							info->logical_offset);
3190 			if (info->status == 0)
3191 				info->bytes_deduped += len;
3192 		}
3193 		fdput(dst_file);
3194 	}
3195 
3196 	ret = copy_to_user(argp, same, size);
3197 	if (ret)
3198 		ret = -EFAULT;
3199 
3200 out:
3201 	mnt_drop_write_file(file);
3202 	kfree(same);
3203 	return ret;
3204 }
3205 
3206 /* Helper to check and see if this root currently has a ref on the given disk
3207  * bytenr.  If it does then we need to update the quota for this root.  This
3208  * doesn't do anything if quotas aren't enabled.
3209  */
3210 static int check_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3211 		     u64 disko)
3212 {
3213 	struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
3214 	struct ulist *roots;
3215 	struct ulist_iterator uiter;
3216 	struct ulist_node *root_node = NULL;
3217 	int ret;
3218 
3219 	if (!root->fs_info->quota_enabled)
3220 		return 1;
3221 
3222 	btrfs_get_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
3223 	ret = btrfs_find_all_roots(trans, root->fs_info, disko,
3224 				   tree_mod_seq_elem.seq, &roots);
3225 	if (ret < 0)
3226 		goto out;
3227 	ret = 0;
3228 	ULIST_ITER_INIT(&uiter);
3229 	while ((root_node = ulist_next(roots, &uiter))) {
3230 		if (root_node->val == root->objectid) {
3231 			ret = 1;
3232 			break;
3233 		}
3234 	}
3235 	ulist_free(roots);
3236 out:
3237 	btrfs_put_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
3238 	return ret;
3239 }
3240 
3241 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
3242 				     struct inode *inode,
3243 				     u64 endoff,
3244 				     const u64 destoff,
3245 				     const u64 olen,
3246 				     int no_time_update)
3247 {
3248 	struct btrfs_root *root = BTRFS_I(inode)->root;
3249 	int ret;
3250 
3251 	inode_inc_iversion(inode);
3252 	if (!no_time_update)
3253 		inode->i_mtime = inode->i_ctime = CURRENT_TIME;
3254 	/*
3255 	 * We round up to the block size at eof when determining which
3256 	 * extents to clone above, but shouldn't round up the file size.
3257 	 */
3258 	if (endoff > destoff + olen)
3259 		endoff = destoff + olen;
3260 	if (endoff > inode->i_size)
3261 		btrfs_i_size_write(inode, endoff);
3262 
3263 	ret = btrfs_update_inode(trans, root, inode);
3264 	if (ret) {
3265 		btrfs_abort_transaction(trans, root, ret);
3266 		btrfs_end_transaction(trans, root);
3267 		goto out;
3268 	}
3269 	ret = btrfs_end_transaction(trans, root);
3270 out:
3271 	return ret;
3272 }
3273 
3274 static void clone_update_extent_map(struct inode *inode,
3275 				    const struct btrfs_trans_handle *trans,
3276 				    const struct btrfs_path *path,
3277 				    const u64 hole_offset,
3278 				    const u64 hole_len)
3279 {
3280 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3281 	struct extent_map *em;
3282 	int ret;
3283 
3284 	em = alloc_extent_map();
3285 	if (!em) {
3286 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3287 			&BTRFS_I(inode)->runtime_flags);
3288 		return;
3289 	}
3290 
3291 	if (path) {
3292 		struct btrfs_file_extent_item *fi;
3293 
3294 		fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
3295 				    struct btrfs_file_extent_item);
3296 		btrfs_extent_item_to_extent_map(inode, path, fi, false, em);
3297 		em->generation = -1;
3298 		if (btrfs_file_extent_type(path->nodes[0], fi) ==
3299 		    BTRFS_FILE_EXTENT_INLINE)
3300 			set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3301 				&BTRFS_I(inode)->runtime_flags);
3302 	} else {
3303 		em->start = hole_offset;
3304 		em->len = hole_len;
3305 		em->ram_bytes = em->len;
3306 		em->orig_start = hole_offset;
3307 		em->block_start = EXTENT_MAP_HOLE;
3308 		em->block_len = 0;
3309 		em->orig_block_len = 0;
3310 		em->compress_type = BTRFS_COMPRESS_NONE;
3311 		em->generation = trans->transid;
3312 	}
3313 
3314 	while (1) {
3315 		write_lock(&em_tree->lock);
3316 		ret = add_extent_mapping(em_tree, em, 1);
3317 		write_unlock(&em_tree->lock);
3318 		if (ret != -EEXIST) {
3319 			free_extent_map(em);
3320 			break;
3321 		}
3322 		btrfs_drop_extent_cache(inode, em->start,
3323 					em->start + em->len - 1, 0);
3324 	}
3325 
3326 	if (ret)
3327 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3328 			&BTRFS_I(inode)->runtime_flags);
3329 }
3330 
3331 /**
3332  * btrfs_clone() - clone a range from inode file to another
3333  *
3334  * @src: Inode to clone from
3335  * @inode: Inode to clone to
3336  * @off: Offset within source to start clone from
3337  * @olen: Original length, passed by user, of range to clone
3338  * @olen_aligned: Block-aligned value of olen
3339  * @destoff: Offset within @inode to start clone
3340  * @no_time_update: Whether to update mtime/ctime on the target inode
3341  */
3342 static int btrfs_clone(struct inode *src, struct inode *inode,
3343 		       const u64 off, const u64 olen, const u64 olen_aligned,
3344 		       const u64 destoff, int no_time_update)
3345 {
3346 	struct btrfs_root *root = BTRFS_I(inode)->root;
3347 	struct btrfs_path *path = NULL;
3348 	struct extent_buffer *leaf;
3349 	struct btrfs_trans_handle *trans;
3350 	char *buf = NULL;
3351 	struct btrfs_key key;
3352 	u32 nritems;
3353 	int slot;
3354 	int ret;
3355 	int no_quota;
3356 	const u64 len = olen_aligned;
3357 	u64 last_disko = 0;
3358 	u64 last_dest_end = destoff;
3359 
3360 	ret = -ENOMEM;
3361 	buf = vmalloc(root->nodesize);
3362 	if (!buf)
3363 		return ret;
3364 
3365 	path = btrfs_alloc_path();
3366 	if (!path) {
3367 		vfree(buf);
3368 		return ret;
3369 	}
3370 
3371 	path->reada = 2;
3372 	/* clone data */
3373 	key.objectid = btrfs_ino(src);
3374 	key.type = BTRFS_EXTENT_DATA_KEY;
3375 	key.offset = off;
3376 
3377 	while (1) {
3378 		u64 next_key_min_offset = key.offset + 1;
3379 
3380 		/*
3381 		 * note the key will change type as we walk through the
3382 		 * tree.
3383 		 */
3384 		path->leave_spinning = 1;
3385 		ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
3386 				0, 0);
3387 		if (ret < 0)
3388 			goto out;
3389 		/*
3390 		 * First search, if no extent item that starts at offset off was
3391 		 * found but the previous item is an extent item, it's possible
3392 		 * it might overlap our target range, therefore process it.
3393 		 */
3394 		if (key.offset == off && ret > 0 && path->slots[0] > 0) {
3395 			btrfs_item_key_to_cpu(path->nodes[0], &key,
3396 					      path->slots[0] - 1);
3397 			if (key.type == BTRFS_EXTENT_DATA_KEY)
3398 				path->slots[0]--;
3399 		}
3400 
3401 		nritems = btrfs_header_nritems(path->nodes[0]);
3402 process_slot:
3403 		no_quota = 1;
3404 		if (path->slots[0] >= nritems) {
3405 			ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
3406 			if (ret < 0)
3407 				goto out;
3408 			if (ret > 0)
3409 				break;
3410 			nritems = btrfs_header_nritems(path->nodes[0]);
3411 		}
3412 		leaf = path->nodes[0];
3413 		slot = path->slots[0];
3414 
3415 		btrfs_item_key_to_cpu(leaf, &key, slot);
3416 		if (key.type > BTRFS_EXTENT_DATA_KEY ||
3417 		    key.objectid != btrfs_ino(src))
3418 			break;
3419 
3420 		if (key.type == BTRFS_EXTENT_DATA_KEY) {
3421 			struct btrfs_file_extent_item *extent;
3422 			int type;
3423 			u32 size;
3424 			struct btrfs_key new_key;
3425 			u64 disko = 0, diskl = 0;
3426 			u64 datao = 0, datal = 0;
3427 			u8 comp;
3428 			u64 drop_start;
3429 
3430 			extent = btrfs_item_ptr(leaf, slot,
3431 						struct btrfs_file_extent_item);
3432 			comp = btrfs_file_extent_compression(leaf, extent);
3433 			type = btrfs_file_extent_type(leaf, extent);
3434 			if (type == BTRFS_FILE_EXTENT_REG ||
3435 			    type == BTRFS_FILE_EXTENT_PREALLOC) {
3436 				disko = btrfs_file_extent_disk_bytenr(leaf,
3437 								      extent);
3438 				diskl = btrfs_file_extent_disk_num_bytes(leaf,
3439 								 extent);
3440 				datao = btrfs_file_extent_offset(leaf, extent);
3441 				datal = btrfs_file_extent_num_bytes(leaf,
3442 								    extent);
3443 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
3444 				/* take upper bound, may be compressed */
3445 				datal = btrfs_file_extent_ram_bytes(leaf,
3446 								    extent);
3447 			}
3448 
3449 			/*
3450 			 * The first search might have left us at an extent
3451 			 * item that ends before our target range's start, can
3452 			 * happen if we have holes and NO_HOLES feature enabled.
3453 			 */
3454 			if (key.offset + datal <= off) {
3455 				path->slots[0]++;
3456 				goto process_slot;
3457 			} else if (key.offset >= off + len) {
3458 				break;
3459 			}
3460 			next_key_min_offset = key.offset + datal;
3461 			size = btrfs_item_size_nr(leaf, slot);
3462 			read_extent_buffer(leaf, buf,
3463 					   btrfs_item_ptr_offset(leaf, slot),
3464 					   size);
3465 
3466 			btrfs_release_path(path);
3467 			path->leave_spinning = 0;
3468 
3469 			memcpy(&new_key, &key, sizeof(new_key));
3470 			new_key.objectid = btrfs_ino(inode);
3471 			if (off <= key.offset)
3472 				new_key.offset = key.offset + destoff - off;
3473 			else
3474 				new_key.offset = destoff;
3475 
3476 			/*
3477 			 * Deal with a hole that doesn't have an extent item
3478 			 * that represents it (NO_HOLES feature enabled).
3479 			 * This hole is either in the middle of the cloning
3480 			 * range or at the beginning (fully overlaps it or
3481 			 * partially overlaps it).
3482 			 */
3483 			if (new_key.offset != last_dest_end)
3484 				drop_start = last_dest_end;
3485 			else
3486 				drop_start = new_key.offset;
3487 
3488 			/*
3489 			 * 1 - adjusting old extent (we may have to split it)
3490 			 * 1 - add new extent
3491 			 * 1 - inode update
3492 			 */
3493 			trans = btrfs_start_transaction(root, 3);
3494 			if (IS_ERR(trans)) {
3495 				ret = PTR_ERR(trans);
3496 				goto out;
3497 			}
3498 
3499 			if (type == BTRFS_FILE_EXTENT_REG ||
3500 			    type == BTRFS_FILE_EXTENT_PREALLOC) {
3501 				/*
3502 				 *    a  | --- range to clone ---|  b
3503 				 * | ------------- extent ------------- |
3504 				 */
3505 
3506 				/* subtract range b */
3507 				if (key.offset + datal > off + len)
3508 					datal = off + len - key.offset;
3509 
3510 				/* subtract range a */
3511 				if (off > key.offset) {
3512 					datao += off - key.offset;
3513 					datal -= off - key.offset;
3514 				}
3515 
3516 				ret = btrfs_drop_extents(trans, root, inode,
3517 							 drop_start,
3518 							 new_key.offset + datal,
3519 							 1);
3520 				if (ret) {
3521 					if (ret != -EOPNOTSUPP)
3522 						btrfs_abort_transaction(trans,
3523 								root, ret);
3524 					btrfs_end_transaction(trans, root);
3525 					goto out;
3526 				}
3527 
3528 				ret = btrfs_insert_empty_item(trans, root, path,
3529 							      &new_key, size);
3530 				if (ret) {
3531 					btrfs_abort_transaction(trans, root,
3532 								ret);
3533 					btrfs_end_transaction(trans, root);
3534 					goto out;
3535 				}
3536 
3537 				leaf = path->nodes[0];
3538 				slot = path->slots[0];
3539 				write_extent_buffer(leaf, buf,
3540 					    btrfs_item_ptr_offset(leaf, slot),
3541 					    size);
3542 
3543 				extent = btrfs_item_ptr(leaf, slot,
3544 						struct btrfs_file_extent_item);
3545 
3546 				/* disko == 0 means it's a hole */
3547 				if (!disko)
3548 					datao = 0;
3549 
3550 				btrfs_set_file_extent_offset(leaf, extent,
3551 							     datao);
3552 				btrfs_set_file_extent_num_bytes(leaf, extent,
3553 								datal);
3554 
3555 				/*
3556 				 * We need to look up the roots that point at
3557 				 * this bytenr and see if the new root does.  If
3558 				 * it does not we need to make sure we update
3559 				 * quotas appropriately.
3560 				 */
3561 				if (disko && root != BTRFS_I(src)->root &&
3562 				    disko != last_disko) {
3563 					no_quota = check_ref(trans, root,
3564 							     disko);
3565 					if (no_quota < 0) {
3566 						btrfs_abort_transaction(trans,
3567 									root,
3568 									ret);
3569 						btrfs_end_transaction(trans,
3570 								      root);
3571 						ret = no_quota;
3572 						goto out;
3573 					}
3574 				}
3575 
3576 				if (disko) {
3577 					inode_add_bytes(inode, datal);
3578 					ret = btrfs_inc_extent_ref(trans, root,
3579 							disko, diskl, 0,
3580 							root->root_key.objectid,
3581 							btrfs_ino(inode),
3582 							new_key.offset - datao,
3583 							no_quota);
3584 					if (ret) {
3585 						btrfs_abort_transaction(trans,
3586 									root,
3587 									ret);
3588 						btrfs_end_transaction(trans,
3589 								      root);
3590 						goto out;
3591 
3592 					}
3593 				}
3594 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
3595 				u64 skip = 0;
3596 				u64 trim = 0;
3597 				u64 aligned_end = 0;
3598 
3599 				/*
3600 				 * Don't copy an inline extent into an offset
3601 				 * greater than zero. Having an inline extent
3602 				 * at such an offset results in chaos as btrfs
3603 				 * isn't prepared for such cases. Just skip
3604 				 * this case for the same reasons as commented
3605 				 * at btrfs_ioctl_clone().
3606 				 */
3607 				if (last_dest_end > 0) {
3608 					ret = -EOPNOTSUPP;
3609 					btrfs_end_transaction(trans, root);
3610 					goto out;
3611 				}
3612 
3613 				if (off > key.offset) {
3614 					skip = off - key.offset;
3615 					new_key.offset += skip;
3616 				}
3617 
3618 				if (key.offset + datal > off + len)
3619 					trim = key.offset + datal - (off + len);
3620 
3621 				if (comp && (skip || trim)) {
3622 					ret = -EINVAL;
3623 					btrfs_end_transaction(trans, root);
3624 					goto out;
3625 				}
3626 				size -= skip + trim;
3627 				datal -= skip + trim;
3628 
3629 				aligned_end = ALIGN(new_key.offset + datal,
3630 						    root->sectorsize);
3631 				ret = btrfs_drop_extents(trans, root, inode,
3632 							 drop_start,
3633 							 aligned_end,
3634 							 1);
3635 				if (ret) {
3636 					if (ret != -EOPNOTSUPP)
3637 						btrfs_abort_transaction(trans,
3638 							root, ret);
3639 					btrfs_end_transaction(trans, root);
3640 					goto out;
3641 				}
3642 
3643 				ret = btrfs_insert_empty_item(trans, root, path,
3644 							      &new_key, size);
3645 				if (ret) {
3646 					btrfs_abort_transaction(trans, root,
3647 								ret);
3648 					btrfs_end_transaction(trans, root);
3649 					goto out;
3650 				}
3651 
3652 				if (skip) {
3653 					u32 start =
3654 					  btrfs_file_extent_calc_inline_size(0);
3655 					memmove(buf+start, buf+start+skip,
3656 						datal);
3657 				}
3658 
3659 				leaf = path->nodes[0];
3660 				slot = path->slots[0];
3661 				write_extent_buffer(leaf, buf,
3662 					    btrfs_item_ptr_offset(leaf, slot),
3663 					    size);
3664 				inode_add_bytes(inode, datal);
3665 			}
3666 
3667 			/* If we have an implicit hole (NO_HOLES feature). */
3668 			if (drop_start < new_key.offset)
3669 				clone_update_extent_map(inode, trans,
3670 						NULL, drop_start,
3671 						new_key.offset - drop_start);
3672 
3673 			clone_update_extent_map(inode, trans, path, 0, 0);
3674 
3675 			btrfs_mark_buffer_dirty(leaf);
3676 			btrfs_release_path(path);
3677 
3678 			last_dest_end = ALIGN(new_key.offset + datal,
3679 					      root->sectorsize);
3680 			ret = clone_finish_inode_update(trans, inode,
3681 							last_dest_end,
3682 							destoff, olen,
3683 							no_time_update);
3684 			if (ret)
3685 				goto out;
3686 			if (new_key.offset + datal >= destoff + len)
3687 				break;
3688 		}
3689 		btrfs_release_path(path);
3690 		key.offset = next_key_min_offset;
3691 	}
3692 	ret = 0;
3693 
3694 	if (last_dest_end < destoff + len) {
3695 		/*
3696 		 * We have an implicit hole (NO_HOLES feature is enabled) that
3697 		 * fully or partially overlaps our cloning range at its end.
3698 		 */
3699 		btrfs_release_path(path);
3700 
3701 		/*
3702 		 * 1 - remove extent(s)
3703 		 * 1 - inode update
3704 		 */
3705 		trans = btrfs_start_transaction(root, 2);
3706 		if (IS_ERR(trans)) {
3707 			ret = PTR_ERR(trans);
3708 			goto out;
3709 		}
3710 		ret = btrfs_drop_extents(trans, root, inode,
3711 					 last_dest_end, destoff + len, 1);
3712 		if (ret) {
3713 			if (ret != -EOPNOTSUPP)
3714 				btrfs_abort_transaction(trans, root, ret);
3715 			btrfs_end_transaction(trans, root);
3716 			goto out;
3717 		}
3718 		clone_update_extent_map(inode, trans, NULL, last_dest_end,
3719 					destoff + len - last_dest_end);
3720 		ret = clone_finish_inode_update(trans, inode, destoff + len,
3721 						destoff, olen, no_time_update);
3722 	}
3723 
3724 out:
3725 	btrfs_free_path(path);
3726 	vfree(buf);
3727 	return ret;
3728 }
3729 
3730 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
3731 				       u64 off, u64 olen, u64 destoff)
3732 {
3733 	struct inode *inode = file_inode(file);
3734 	struct btrfs_root *root = BTRFS_I(inode)->root;
3735 	struct fd src_file;
3736 	struct inode *src;
3737 	int ret;
3738 	u64 len = olen;
3739 	u64 bs = root->fs_info->sb->s_blocksize;
3740 	int same_inode = 0;
3741 
3742 	/*
3743 	 * TODO:
3744 	 * - split compressed inline extents.  annoying: we need to
3745 	 *   decompress into destination's address_space (the file offset
3746 	 *   may change, so source mapping won't do), then recompress (or
3747 	 *   otherwise reinsert) a subrange.
3748 	 *
3749 	 * - split destination inode's inline extents.  The inline extents can
3750 	 *   be either compressed or non-compressed.
3751 	 */
3752 
3753 	/* the destination must be opened for writing */
3754 	if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
3755 		return -EINVAL;
3756 
3757 	if (btrfs_root_readonly(root))
3758 		return -EROFS;
3759 
3760 	ret = mnt_want_write_file(file);
3761 	if (ret)
3762 		return ret;
3763 
3764 	src_file = fdget(srcfd);
3765 	if (!src_file.file) {
3766 		ret = -EBADF;
3767 		goto out_drop_write;
3768 	}
3769 
3770 	ret = -EXDEV;
3771 	if (src_file.file->f_path.mnt != file->f_path.mnt)
3772 		goto out_fput;
3773 
3774 	src = file_inode(src_file.file);
3775 
3776 	ret = -EINVAL;
3777 	if (src == inode)
3778 		same_inode = 1;
3779 
3780 	/* the src must be open for reading */
3781 	if (!(src_file.file->f_mode & FMODE_READ))
3782 		goto out_fput;
3783 
3784 	/* don't make the dst file partly checksummed */
3785 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3786 	    (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
3787 		goto out_fput;
3788 
3789 	ret = -EISDIR;
3790 	if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
3791 		goto out_fput;
3792 
3793 	ret = -EXDEV;
3794 	if (src->i_sb != inode->i_sb)
3795 		goto out_fput;
3796 
3797 	if (!same_inode) {
3798 		btrfs_double_inode_lock(src, inode);
3799 	} else {
3800 		mutex_lock(&src->i_mutex);
3801 	}
3802 
3803 	/* determine range to clone */
3804 	ret = -EINVAL;
3805 	if (off + len > src->i_size || off + len < off)
3806 		goto out_unlock;
3807 	if (len == 0)
3808 		olen = len = src->i_size - off;
3809 	/* if we extend to eof, continue to block boundary */
3810 	if (off + len == src->i_size)
3811 		len = ALIGN(src->i_size, bs) - off;
3812 
3813 	if (len == 0) {
3814 		ret = 0;
3815 		goto out_unlock;
3816 	}
3817 
3818 	/* verify the end result is block aligned */
3819 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
3820 	    !IS_ALIGNED(destoff, bs))
3821 		goto out_unlock;
3822 
3823 	/* verify if ranges are overlapped within the same file */
3824 	if (same_inode) {
3825 		if (destoff + len > off && destoff < off + len)
3826 			goto out_unlock;
3827 	}
3828 
3829 	if (destoff > inode->i_size) {
3830 		ret = btrfs_cont_expand(inode, inode->i_size, destoff);
3831 		if (ret)
3832 			goto out_unlock;
3833 	}
3834 
3835 	/*
3836 	 * Lock the target range too. Right after we replace the file extent
3837 	 * items in the fs tree (which now point to the cloned data), we might
3838 	 * have a worker replace them with extent items relative to a write
3839 	 * operation that was issued before this clone operation (i.e. confront
3840 	 * with inode.c:btrfs_finish_ordered_io).
3841 	 */
3842 	if (same_inode) {
3843 		u64 lock_start = min_t(u64, off, destoff);
3844 		u64 lock_len = max_t(u64, off, destoff) + len - lock_start;
3845 
3846 		lock_extent_range(src, lock_start, lock_len);
3847 	} else {
3848 		btrfs_double_extent_lock(src, off, inode, destoff, len);
3849 	}
3850 
3851 	ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
3852 
3853 	if (same_inode) {
3854 		u64 lock_start = min_t(u64, off, destoff);
3855 		u64 lock_end = max_t(u64, off, destoff) + len - 1;
3856 
3857 		unlock_extent(&BTRFS_I(src)->io_tree, lock_start, lock_end);
3858 	} else {
3859 		btrfs_double_extent_unlock(src, off, inode, destoff, len);
3860 	}
3861 	/*
3862 	 * Truncate page cache pages so that future reads will see the cloned
3863 	 * data immediately and not the previous data.
3864 	 */
3865 	truncate_inode_pages_range(&inode->i_data, destoff,
3866 				   PAGE_CACHE_ALIGN(destoff + len) - 1);
3867 out_unlock:
3868 	if (!same_inode)
3869 		btrfs_double_inode_unlock(src, inode);
3870 	else
3871 		mutex_unlock(&src->i_mutex);
3872 out_fput:
3873 	fdput(src_file);
3874 out_drop_write:
3875 	mnt_drop_write_file(file);
3876 	return ret;
3877 }
3878 
3879 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
3880 {
3881 	struct btrfs_ioctl_clone_range_args args;
3882 
3883 	if (copy_from_user(&args, argp, sizeof(args)))
3884 		return -EFAULT;
3885 	return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
3886 				 args.src_length, args.dest_offset);
3887 }
3888 
3889 /*
3890  * there are many ways the trans_start and trans_end ioctls can lead
3891  * to deadlocks.  They should only be used by applications that
3892  * basically own the machine, and have a very in depth understanding
3893  * of all the possible deadlocks and enospc problems.
3894  */
3895 static long btrfs_ioctl_trans_start(struct file *file)
3896 {
3897 	struct inode *inode = file_inode(file);
3898 	struct btrfs_root *root = BTRFS_I(inode)->root;
3899 	struct btrfs_trans_handle *trans;
3900 	int ret;
3901 
3902 	ret = -EPERM;
3903 	if (!capable(CAP_SYS_ADMIN))
3904 		goto out;
3905 
3906 	ret = -EINPROGRESS;
3907 	if (file->private_data)
3908 		goto out;
3909 
3910 	ret = -EROFS;
3911 	if (btrfs_root_readonly(root))
3912 		goto out;
3913 
3914 	ret = mnt_want_write_file(file);
3915 	if (ret)
3916 		goto out;
3917 
3918 	atomic_inc(&root->fs_info->open_ioctl_trans);
3919 
3920 	ret = -ENOMEM;
3921 	trans = btrfs_start_ioctl_transaction(root);
3922 	if (IS_ERR(trans))
3923 		goto out_drop;
3924 
3925 	file->private_data = trans;
3926 	return 0;
3927 
3928 out_drop:
3929 	atomic_dec(&root->fs_info->open_ioctl_trans);
3930 	mnt_drop_write_file(file);
3931 out:
3932 	return ret;
3933 }
3934 
3935 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
3936 {
3937 	struct inode *inode = file_inode(file);
3938 	struct btrfs_root *root = BTRFS_I(inode)->root;
3939 	struct btrfs_root *new_root;
3940 	struct btrfs_dir_item *di;
3941 	struct btrfs_trans_handle *trans;
3942 	struct btrfs_path *path;
3943 	struct btrfs_key location;
3944 	struct btrfs_disk_key disk_key;
3945 	u64 objectid = 0;
3946 	u64 dir_id;
3947 	int ret;
3948 
3949 	if (!capable(CAP_SYS_ADMIN))
3950 		return -EPERM;
3951 
3952 	ret = mnt_want_write_file(file);
3953 	if (ret)
3954 		return ret;
3955 
3956 	if (copy_from_user(&objectid, argp, sizeof(objectid))) {
3957 		ret = -EFAULT;
3958 		goto out;
3959 	}
3960 
3961 	if (!objectid)
3962 		objectid = BTRFS_FS_TREE_OBJECTID;
3963 
3964 	location.objectid = objectid;
3965 	location.type = BTRFS_ROOT_ITEM_KEY;
3966 	location.offset = (u64)-1;
3967 
3968 	new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
3969 	if (IS_ERR(new_root)) {
3970 		ret = PTR_ERR(new_root);
3971 		goto out;
3972 	}
3973 
3974 	path = btrfs_alloc_path();
3975 	if (!path) {
3976 		ret = -ENOMEM;
3977 		goto out;
3978 	}
3979 	path->leave_spinning = 1;
3980 
3981 	trans = btrfs_start_transaction(root, 1);
3982 	if (IS_ERR(trans)) {
3983 		btrfs_free_path(path);
3984 		ret = PTR_ERR(trans);
3985 		goto out;
3986 	}
3987 
3988 	dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
3989 	di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
3990 				   dir_id, "default", 7, 1);
3991 	if (IS_ERR_OR_NULL(di)) {
3992 		btrfs_free_path(path);
3993 		btrfs_end_transaction(trans, root);
3994 		btrfs_err(new_root->fs_info, "Umm, you don't have the default dir"
3995 			   "item, this isn't going to work");
3996 		ret = -ENOENT;
3997 		goto out;
3998 	}
3999 
4000 	btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
4001 	btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
4002 	btrfs_mark_buffer_dirty(path->nodes[0]);
4003 	btrfs_free_path(path);
4004 
4005 	btrfs_set_fs_incompat(root->fs_info, DEFAULT_SUBVOL);
4006 	btrfs_end_transaction(trans, root);
4007 out:
4008 	mnt_drop_write_file(file);
4009 	return ret;
4010 }
4011 
4012 void btrfs_get_block_group_info(struct list_head *groups_list,
4013 				struct btrfs_ioctl_space_info *space)
4014 {
4015 	struct btrfs_block_group_cache *block_group;
4016 
4017 	space->total_bytes = 0;
4018 	space->used_bytes = 0;
4019 	space->flags = 0;
4020 	list_for_each_entry(block_group, groups_list, list) {
4021 		space->flags = block_group->flags;
4022 		space->total_bytes += block_group->key.offset;
4023 		space->used_bytes +=
4024 			btrfs_block_group_used(&block_group->item);
4025 	}
4026 }
4027 
4028 static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
4029 {
4030 	struct btrfs_ioctl_space_args space_args;
4031 	struct btrfs_ioctl_space_info space;
4032 	struct btrfs_ioctl_space_info *dest;
4033 	struct btrfs_ioctl_space_info *dest_orig;
4034 	struct btrfs_ioctl_space_info __user *user_dest;
4035 	struct btrfs_space_info *info;
4036 	u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
4037 		       BTRFS_BLOCK_GROUP_SYSTEM,
4038 		       BTRFS_BLOCK_GROUP_METADATA,
4039 		       BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
4040 	int num_types = 4;
4041 	int alloc_size;
4042 	int ret = 0;
4043 	u64 slot_count = 0;
4044 	int i, c;
4045 
4046 	if (copy_from_user(&space_args,
4047 			   (struct btrfs_ioctl_space_args __user *)arg,
4048 			   sizeof(space_args)))
4049 		return -EFAULT;
4050 
4051 	for (i = 0; i < num_types; i++) {
4052 		struct btrfs_space_info *tmp;
4053 
4054 		info = NULL;
4055 		rcu_read_lock();
4056 		list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
4057 					list) {
4058 			if (tmp->flags == types[i]) {
4059 				info = tmp;
4060 				break;
4061 			}
4062 		}
4063 		rcu_read_unlock();
4064 
4065 		if (!info)
4066 			continue;
4067 
4068 		down_read(&info->groups_sem);
4069 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4070 			if (!list_empty(&info->block_groups[c]))
4071 				slot_count++;
4072 		}
4073 		up_read(&info->groups_sem);
4074 	}
4075 
4076 	/*
4077 	 * Global block reserve, exported as a space_info
4078 	 */
4079 	slot_count++;
4080 
4081 	/* space_slots == 0 means they are asking for a count */
4082 	if (space_args.space_slots == 0) {
4083 		space_args.total_spaces = slot_count;
4084 		goto out;
4085 	}
4086 
4087 	slot_count = min_t(u64, space_args.space_slots, slot_count);
4088 
4089 	alloc_size = sizeof(*dest) * slot_count;
4090 
4091 	/* we generally have at most 6 or so space infos, one for each raid
4092 	 * level.  So, a whole page should be more than enough for everyone
4093 	 */
4094 	if (alloc_size > PAGE_CACHE_SIZE)
4095 		return -ENOMEM;
4096 
4097 	space_args.total_spaces = 0;
4098 	dest = kmalloc(alloc_size, GFP_NOFS);
4099 	if (!dest)
4100 		return -ENOMEM;
4101 	dest_orig = dest;
4102 
4103 	/* now we have a buffer to copy into */
4104 	for (i = 0; i < num_types; i++) {
4105 		struct btrfs_space_info *tmp;
4106 
4107 		if (!slot_count)
4108 			break;
4109 
4110 		info = NULL;
4111 		rcu_read_lock();
4112 		list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
4113 					list) {
4114 			if (tmp->flags == types[i]) {
4115 				info = tmp;
4116 				break;
4117 			}
4118 		}
4119 		rcu_read_unlock();
4120 
4121 		if (!info)
4122 			continue;
4123 		down_read(&info->groups_sem);
4124 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4125 			if (!list_empty(&info->block_groups[c])) {
4126 				btrfs_get_block_group_info(
4127 					&info->block_groups[c], &space);
4128 				memcpy(dest, &space, sizeof(space));
4129 				dest++;
4130 				space_args.total_spaces++;
4131 				slot_count--;
4132 			}
4133 			if (!slot_count)
4134 				break;
4135 		}
4136 		up_read(&info->groups_sem);
4137 	}
4138 
4139 	/*
4140 	 * Add global block reserve
4141 	 */
4142 	if (slot_count) {
4143 		struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv;
4144 
4145 		spin_lock(&block_rsv->lock);
4146 		space.total_bytes = block_rsv->size;
4147 		space.used_bytes = block_rsv->size - block_rsv->reserved;
4148 		spin_unlock(&block_rsv->lock);
4149 		space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
4150 		memcpy(dest, &space, sizeof(space));
4151 		space_args.total_spaces++;
4152 	}
4153 
4154 	user_dest = (struct btrfs_ioctl_space_info __user *)
4155 		(arg + sizeof(struct btrfs_ioctl_space_args));
4156 
4157 	if (copy_to_user(user_dest, dest_orig, alloc_size))
4158 		ret = -EFAULT;
4159 
4160 	kfree(dest_orig);
4161 out:
4162 	if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
4163 		ret = -EFAULT;
4164 
4165 	return ret;
4166 }
4167 
4168 /*
4169  * there are many ways the trans_start and trans_end ioctls can lead
4170  * to deadlocks.  They should only be used by applications that
4171  * basically own the machine, and have a very in depth understanding
4172  * of all the possible deadlocks and enospc problems.
4173  */
4174 long btrfs_ioctl_trans_end(struct file *file)
4175 {
4176 	struct inode *inode = file_inode(file);
4177 	struct btrfs_root *root = BTRFS_I(inode)->root;
4178 	struct btrfs_trans_handle *trans;
4179 
4180 	trans = file->private_data;
4181 	if (!trans)
4182 		return -EINVAL;
4183 	file->private_data = NULL;
4184 
4185 	btrfs_end_transaction(trans, root);
4186 
4187 	atomic_dec(&root->fs_info->open_ioctl_trans);
4188 
4189 	mnt_drop_write_file(file);
4190 	return 0;
4191 }
4192 
4193 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
4194 					    void __user *argp)
4195 {
4196 	struct btrfs_trans_handle *trans;
4197 	u64 transid;
4198 	int ret;
4199 
4200 	trans = btrfs_attach_transaction_barrier(root);
4201 	if (IS_ERR(trans)) {
4202 		if (PTR_ERR(trans) != -ENOENT)
4203 			return PTR_ERR(trans);
4204 
4205 		/* No running transaction, don't bother */
4206 		transid = root->fs_info->last_trans_committed;
4207 		goto out;
4208 	}
4209 	transid = trans->transid;
4210 	ret = btrfs_commit_transaction_async(trans, root, 0);
4211 	if (ret) {
4212 		btrfs_end_transaction(trans, root);
4213 		return ret;
4214 	}
4215 out:
4216 	if (argp)
4217 		if (copy_to_user(argp, &transid, sizeof(transid)))
4218 			return -EFAULT;
4219 	return 0;
4220 }
4221 
4222 static noinline long btrfs_ioctl_wait_sync(struct btrfs_root *root,
4223 					   void __user *argp)
4224 {
4225 	u64 transid;
4226 
4227 	if (argp) {
4228 		if (copy_from_user(&transid, argp, sizeof(transid)))
4229 			return -EFAULT;
4230 	} else {
4231 		transid = 0;  /* current trans */
4232 	}
4233 	return btrfs_wait_for_commit(root, transid);
4234 }
4235 
4236 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
4237 {
4238 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4239 	struct btrfs_ioctl_scrub_args *sa;
4240 	int ret;
4241 
4242 	if (!capable(CAP_SYS_ADMIN))
4243 		return -EPERM;
4244 
4245 	sa = memdup_user(arg, sizeof(*sa));
4246 	if (IS_ERR(sa))
4247 		return PTR_ERR(sa);
4248 
4249 	if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
4250 		ret = mnt_want_write_file(file);
4251 		if (ret)
4252 			goto out;
4253 	}
4254 
4255 	ret = btrfs_scrub_dev(root->fs_info, sa->devid, sa->start, sa->end,
4256 			      &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
4257 			      0);
4258 
4259 	if (copy_to_user(arg, sa, sizeof(*sa)))
4260 		ret = -EFAULT;
4261 
4262 	if (!(sa->flags & BTRFS_SCRUB_READONLY))
4263 		mnt_drop_write_file(file);
4264 out:
4265 	kfree(sa);
4266 	return ret;
4267 }
4268 
4269 static long btrfs_ioctl_scrub_cancel(struct btrfs_root *root, void __user *arg)
4270 {
4271 	if (!capable(CAP_SYS_ADMIN))
4272 		return -EPERM;
4273 
4274 	return btrfs_scrub_cancel(root->fs_info);
4275 }
4276 
4277 static long btrfs_ioctl_scrub_progress(struct btrfs_root *root,
4278 				       void __user *arg)
4279 {
4280 	struct btrfs_ioctl_scrub_args *sa;
4281 	int ret;
4282 
4283 	if (!capable(CAP_SYS_ADMIN))
4284 		return -EPERM;
4285 
4286 	sa = memdup_user(arg, sizeof(*sa));
4287 	if (IS_ERR(sa))
4288 		return PTR_ERR(sa);
4289 
4290 	ret = btrfs_scrub_progress(root, sa->devid, &sa->progress);
4291 
4292 	if (copy_to_user(arg, sa, sizeof(*sa)))
4293 		ret = -EFAULT;
4294 
4295 	kfree(sa);
4296 	return ret;
4297 }
4298 
4299 static long btrfs_ioctl_get_dev_stats(struct btrfs_root *root,
4300 				      void __user *arg)
4301 {
4302 	struct btrfs_ioctl_get_dev_stats *sa;
4303 	int ret;
4304 
4305 	sa = memdup_user(arg, sizeof(*sa));
4306 	if (IS_ERR(sa))
4307 		return PTR_ERR(sa);
4308 
4309 	if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
4310 		kfree(sa);
4311 		return -EPERM;
4312 	}
4313 
4314 	ret = btrfs_get_dev_stats(root, sa);
4315 
4316 	if (copy_to_user(arg, sa, sizeof(*sa)))
4317 		ret = -EFAULT;
4318 
4319 	kfree(sa);
4320 	return ret;
4321 }
4322 
4323 static long btrfs_ioctl_dev_replace(struct btrfs_root *root, void __user *arg)
4324 {
4325 	struct btrfs_ioctl_dev_replace_args *p;
4326 	int ret;
4327 
4328 	if (!capable(CAP_SYS_ADMIN))
4329 		return -EPERM;
4330 
4331 	p = memdup_user(arg, sizeof(*p));
4332 	if (IS_ERR(p))
4333 		return PTR_ERR(p);
4334 
4335 	switch (p->cmd) {
4336 	case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
4337 		if (root->fs_info->sb->s_flags & MS_RDONLY) {
4338 			ret = -EROFS;
4339 			goto out;
4340 		}
4341 		if (atomic_xchg(
4342 			&root->fs_info->mutually_exclusive_operation_running,
4343 			1)) {
4344 			ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4345 		} else {
4346 			ret = btrfs_dev_replace_start(root, p);
4347 			atomic_set(
4348 			 &root->fs_info->mutually_exclusive_operation_running,
4349 			 0);
4350 		}
4351 		break;
4352 	case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
4353 		btrfs_dev_replace_status(root->fs_info, p);
4354 		ret = 0;
4355 		break;
4356 	case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
4357 		ret = btrfs_dev_replace_cancel(root->fs_info, p);
4358 		break;
4359 	default:
4360 		ret = -EINVAL;
4361 		break;
4362 	}
4363 
4364 	if (copy_to_user(arg, p, sizeof(*p)))
4365 		ret = -EFAULT;
4366 out:
4367 	kfree(p);
4368 	return ret;
4369 }
4370 
4371 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
4372 {
4373 	int ret = 0;
4374 	int i;
4375 	u64 rel_ptr;
4376 	int size;
4377 	struct btrfs_ioctl_ino_path_args *ipa = NULL;
4378 	struct inode_fs_paths *ipath = NULL;
4379 	struct btrfs_path *path;
4380 
4381 	if (!capable(CAP_DAC_READ_SEARCH))
4382 		return -EPERM;
4383 
4384 	path = btrfs_alloc_path();
4385 	if (!path) {
4386 		ret = -ENOMEM;
4387 		goto out;
4388 	}
4389 
4390 	ipa = memdup_user(arg, sizeof(*ipa));
4391 	if (IS_ERR(ipa)) {
4392 		ret = PTR_ERR(ipa);
4393 		ipa = NULL;
4394 		goto out;
4395 	}
4396 
4397 	size = min_t(u32, ipa->size, 4096);
4398 	ipath = init_ipath(size, root, path);
4399 	if (IS_ERR(ipath)) {
4400 		ret = PTR_ERR(ipath);
4401 		ipath = NULL;
4402 		goto out;
4403 	}
4404 
4405 	ret = paths_from_inode(ipa->inum, ipath);
4406 	if (ret < 0)
4407 		goto out;
4408 
4409 	for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
4410 		rel_ptr = ipath->fspath->val[i] -
4411 			  (u64)(unsigned long)ipath->fspath->val;
4412 		ipath->fspath->val[i] = rel_ptr;
4413 	}
4414 
4415 	ret = copy_to_user((void *)(unsigned long)ipa->fspath,
4416 			   (void *)(unsigned long)ipath->fspath, size);
4417 	if (ret) {
4418 		ret = -EFAULT;
4419 		goto out;
4420 	}
4421 
4422 out:
4423 	btrfs_free_path(path);
4424 	free_ipath(ipath);
4425 	kfree(ipa);
4426 
4427 	return ret;
4428 }
4429 
4430 static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
4431 {
4432 	struct btrfs_data_container *inodes = ctx;
4433 	const size_t c = 3 * sizeof(u64);
4434 
4435 	if (inodes->bytes_left >= c) {
4436 		inodes->bytes_left -= c;
4437 		inodes->val[inodes->elem_cnt] = inum;
4438 		inodes->val[inodes->elem_cnt + 1] = offset;
4439 		inodes->val[inodes->elem_cnt + 2] = root;
4440 		inodes->elem_cnt += 3;
4441 	} else {
4442 		inodes->bytes_missing += c - inodes->bytes_left;
4443 		inodes->bytes_left = 0;
4444 		inodes->elem_missed += 3;
4445 	}
4446 
4447 	return 0;
4448 }
4449 
4450 static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
4451 					void __user *arg)
4452 {
4453 	int ret = 0;
4454 	int size;
4455 	struct btrfs_ioctl_logical_ino_args *loi;
4456 	struct btrfs_data_container *inodes = NULL;
4457 	struct btrfs_path *path = NULL;
4458 
4459 	if (!capable(CAP_SYS_ADMIN))
4460 		return -EPERM;
4461 
4462 	loi = memdup_user(arg, sizeof(*loi));
4463 	if (IS_ERR(loi)) {
4464 		ret = PTR_ERR(loi);
4465 		loi = NULL;
4466 		goto out;
4467 	}
4468 
4469 	path = btrfs_alloc_path();
4470 	if (!path) {
4471 		ret = -ENOMEM;
4472 		goto out;
4473 	}
4474 
4475 	size = min_t(u32, loi->size, 64 * 1024);
4476 	inodes = init_data_container(size);
4477 	if (IS_ERR(inodes)) {
4478 		ret = PTR_ERR(inodes);
4479 		inodes = NULL;
4480 		goto out;
4481 	}
4482 
4483 	ret = iterate_inodes_from_logical(loi->logical, root->fs_info, path,
4484 					  build_ino_list, inodes);
4485 	if (ret == -EINVAL)
4486 		ret = -ENOENT;
4487 	if (ret < 0)
4488 		goto out;
4489 
4490 	ret = copy_to_user((void *)(unsigned long)loi->inodes,
4491 			   (void *)(unsigned long)inodes, size);
4492 	if (ret)
4493 		ret = -EFAULT;
4494 
4495 out:
4496 	btrfs_free_path(path);
4497 	vfree(inodes);
4498 	kfree(loi);
4499 
4500 	return ret;
4501 }
4502 
4503 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
4504 			       struct btrfs_ioctl_balance_args *bargs)
4505 {
4506 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4507 
4508 	bargs->flags = bctl->flags;
4509 
4510 	if (atomic_read(&fs_info->balance_running))
4511 		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
4512 	if (atomic_read(&fs_info->balance_pause_req))
4513 		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
4514 	if (atomic_read(&fs_info->balance_cancel_req))
4515 		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
4516 
4517 	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
4518 	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
4519 	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
4520 
4521 	if (lock) {
4522 		spin_lock(&fs_info->balance_lock);
4523 		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4524 		spin_unlock(&fs_info->balance_lock);
4525 	} else {
4526 		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4527 	}
4528 }
4529 
4530 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
4531 {
4532 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4533 	struct btrfs_fs_info *fs_info = root->fs_info;
4534 	struct btrfs_ioctl_balance_args *bargs;
4535 	struct btrfs_balance_control *bctl;
4536 	bool need_unlock; /* for mut. excl. ops lock */
4537 	int ret;
4538 
4539 	if (!capable(CAP_SYS_ADMIN))
4540 		return -EPERM;
4541 
4542 	ret = mnt_want_write_file(file);
4543 	if (ret)
4544 		return ret;
4545 
4546 again:
4547 	if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
4548 		mutex_lock(&fs_info->volume_mutex);
4549 		mutex_lock(&fs_info->balance_mutex);
4550 		need_unlock = true;
4551 		goto locked;
4552 	}
4553 
4554 	/*
4555 	 * mut. excl. ops lock is locked.  Three possibilites:
4556 	 *   (1) some other op is running
4557 	 *   (2) balance is running
4558 	 *   (3) balance is paused -- special case (think resume)
4559 	 */
4560 	mutex_lock(&fs_info->balance_mutex);
4561 	if (fs_info->balance_ctl) {
4562 		/* this is either (2) or (3) */
4563 		if (!atomic_read(&fs_info->balance_running)) {
4564 			mutex_unlock(&fs_info->balance_mutex);
4565 			if (!mutex_trylock(&fs_info->volume_mutex))
4566 				goto again;
4567 			mutex_lock(&fs_info->balance_mutex);
4568 
4569 			if (fs_info->balance_ctl &&
4570 			    !atomic_read(&fs_info->balance_running)) {
4571 				/* this is (3) */
4572 				need_unlock = false;
4573 				goto locked;
4574 			}
4575 
4576 			mutex_unlock(&fs_info->balance_mutex);
4577 			mutex_unlock(&fs_info->volume_mutex);
4578 			goto again;
4579 		} else {
4580 			/* this is (2) */
4581 			mutex_unlock(&fs_info->balance_mutex);
4582 			ret = -EINPROGRESS;
4583 			goto out;
4584 		}
4585 	} else {
4586 		/* this is (1) */
4587 		mutex_unlock(&fs_info->balance_mutex);
4588 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4589 		goto out;
4590 	}
4591 
4592 locked:
4593 	BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));
4594 
4595 	if (arg) {
4596 		bargs = memdup_user(arg, sizeof(*bargs));
4597 		if (IS_ERR(bargs)) {
4598 			ret = PTR_ERR(bargs);
4599 			goto out_unlock;
4600 		}
4601 
4602 		if (bargs->flags & BTRFS_BALANCE_RESUME) {
4603 			if (!fs_info->balance_ctl) {
4604 				ret = -ENOTCONN;
4605 				goto out_bargs;
4606 			}
4607 
4608 			bctl = fs_info->balance_ctl;
4609 			spin_lock(&fs_info->balance_lock);
4610 			bctl->flags |= BTRFS_BALANCE_RESUME;
4611 			spin_unlock(&fs_info->balance_lock);
4612 
4613 			goto do_balance;
4614 		}
4615 	} else {
4616 		bargs = NULL;
4617 	}
4618 
4619 	if (fs_info->balance_ctl) {
4620 		ret = -EINPROGRESS;
4621 		goto out_bargs;
4622 	}
4623 
4624 	bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
4625 	if (!bctl) {
4626 		ret = -ENOMEM;
4627 		goto out_bargs;
4628 	}
4629 
4630 	bctl->fs_info = fs_info;
4631 	if (arg) {
4632 		memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
4633 		memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
4634 		memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
4635 
4636 		bctl->flags = bargs->flags;
4637 	} else {
4638 		/* balance everything - no filters */
4639 		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
4640 	}
4641 
4642 	if (bctl->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
4643 		ret = -EINVAL;
4644 		goto out_bctl;
4645 	}
4646 
4647 do_balance:
4648 	/*
4649 	 * Ownership of bctl and mutually_exclusive_operation_running
4650 	 * goes to to btrfs_balance.  bctl is freed in __cancel_balance,
4651 	 * or, if restriper was paused all the way until unmount, in
4652 	 * free_fs_info.  mutually_exclusive_operation_running is
4653 	 * cleared in __cancel_balance.
4654 	 */
4655 	need_unlock = false;
4656 
4657 	ret = btrfs_balance(bctl, bargs);
4658 	bctl = NULL;
4659 
4660 	if (arg) {
4661 		if (copy_to_user(arg, bargs, sizeof(*bargs)))
4662 			ret = -EFAULT;
4663 	}
4664 
4665 out_bctl:
4666 	kfree(bctl);
4667 out_bargs:
4668 	kfree(bargs);
4669 out_unlock:
4670 	mutex_unlock(&fs_info->balance_mutex);
4671 	mutex_unlock(&fs_info->volume_mutex);
4672 	if (need_unlock)
4673 		atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
4674 out:
4675 	mnt_drop_write_file(file);
4676 	return ret;
4677 }
4678 
4679 static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd)
4680 {
4681 	if (!capable(CAP_SYS_ADMIN))
4682 		return -EPERM;
4683 
4684 	switch (cmd) {
4685 	case BTRFS_BALANCE_CTL_PAUSE:
4686 		return btrfs_pause_balance(root->fs_info);
4687 	case BTRFS_BALANCE_CTL_CANCEL:
4688 		return btrfs_cancel_balance(root->fs_info);
4689 	}
4690 
4691 	return -EINVAL;
4692 }
4693 
4694 static long btrfs_ioctl_balance_progress(struct btrfs_root *root,
4695 					 void __user *arg)
4696 {
4697 	struct btrfs_fs_info *fs_info = root->fs_info;
4698 	struct btrfs_ioctl_balance_args *bargs;
4699 	int ret = 0;
4700 
4701 	if (!capable(CAP_SYS_ADMIN))
4702 		return -EPERM;
4703 
4704 	mutex_lock(&fs_info->balance_mutex);
4705 	if (!fs_info->balance_ctl) {
4706 		ret = -ENOTCONN;
4707 		goto out;
4708 	}
4709 
4710 	bargs = kzalloc(sizeof(*bargs), GFP_NOFS);
4711 	if (!bargs) {
4712 		ret = -ENOMEM;
4713 		goto out;
4714 	}
4715 
4716 	update_ioctl_balance_args(fs_info, 1, bargs);
4717 
4718 	if (copy_to_user(arg, bargs, sizeof(*bargs)))
4719 		ret = -EFAULT;
4720 
4721 	kfree(bargs);
4722 out:
4723 	mutex_unlock(&fs_info->balance_mutex);
4724 	return ret;
4725 }
4726 
4727 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
4728 {
4729 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4730 	struct btrfs_ioctl_quota_ctl_args *sa;
4731 	struct btrfs_trans_handle *trans = NULL;
4732 	int ret;
4733 	int err;
4734 
4735 	if (!capable(CAP_SYS_ADMIN))
4736 		return -EPERM;
4737 
4738 	ret = mnt_want_write_file(file);
4739 	if (ret)
4740 		return ret;
4741 
4742 	sa = memdup_user(arg, sizeof(*sa));
4743 	if (IS_ERR(sa)) {
4744 		ret = PTR_ERR(sa);
4745 		goto drop_write;
4746 	}
4747 
4748 	down_write(&root->fs_info->subvol_sem);
4749 	trans = btrfs_start_transaction(root->fs_info->tree_root, 2);
4750 	if (IS_ERR(trans)) {
4751 		ret = PTR_ERR(trans);
4752 		goto out;
4753 	}
4754 
4755 	switch (sa->cmd) {
4756 	case BTRFS_QUOTA_CTL_ENABLE:
4757 		ret = btrfs_quota_enable(trans, root->fs_info);
4758 		break;
4759 	case BTRFS_QUOTA_CTL_DISABLE:
4760 		ret = btrfs_quota_disable(trans, root->fs_info);
4761 		break;
4762 	default:
4763 		ret = -EINVAL;
4764 		break;
4765 	}
4766 
4767 	err = btrfs_commit_transaction(trans, root->fs_info->tree_root);
4768 	if (err && !ret)
4769 		ret = err;
4770 out:
4771 	kfree(sa);
4772 	up_write(&root->fs_info->subvol_sem);
4773 drop_write:
4774 	mnt_drop_write_file(file);
4775 	return ret;
4776 }
4777 
4778 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
4779 {
4780 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4781 	struct btrfs_ioctl_qgroup_assign_args *sa;
4782 	struct btrfs_trans_handle *trans;
4783 	int ret;
4784 	int err;
4785 
4786 	if (!capable(CAP_SYS_ADMIN))
4787 		return -EPERM;
4788 
4789 	ret = mnt_want_write_file(file);
4790 	if (ret)
4791 		return ret;
4792 
4793 	sa = memdup_user(arg, sizeof(*sa));
4794 	if (IS_ERR(sa)) {
4795 		ret = PTR_ERR(sa);
4796 		goto drop_write;
4797 	}
4798 
4799 	trans = btrfs_join_transaction(root);
4800 	if (IS_ERR(trans)) {
4801 		ret = PTR_ERR(trans);
4802 		goto out;
4803 	}
4804 
4805 	/* FIXME: check if the IDs really exist */
4806 	if (sa->assign) {
4807 		ret = btrfs_add_qgroup_relation(trans, root->fs_info,
4808 						sa->src, sa->dst);
4809 	} else {
4810 		ret = btrfs_del_qgroup_relation(trans, root->fs_info,
4811 						sa->src, sa->dst);
4812 	}
4813 
4814 	/* update qgroup status and info */
4815 	err = btrfs_run_qgroups(trans, root->fs_info);
4816 	if (err < 0)
4817 		btrfs_error(root->fs_info, ret,
4818 			    "failed to update qgroup status and info\n");
4819 	err = btrfs_end_transaction(trans, root);
4820 	if (err && !ret)
4821 		ret = err;
4822 
4823 out:
4824 	kfree(sa);
4825 drop_write:
4826 	mnt_drop_write_file(file);
4827 	return ret;
4828 }
4829 
4830 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
4831 {
4832 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4833 	struct btrfs_ioctl_qgroup_create_args *sa;
4834 	struct btrfs_trans_handle *trans;
4835 	int ret;
4836 	int err;
4837 
4838 	if (!capable(CAP_SYS_ADMIN))
4839 		return -EPERM;
4840 
4841 	ret = mnt_want_write_file(file);
4842 	if (ret)
4843 		return ret;
4844 
4845 	sa = memdup_user(arg, sizeof(*sa));
4846 	if (IS_ERR(sa)) {
4847 		ret = PTR_ERR(sa);
4848 		goto drop_write;
4849 	}
4850 
4851 	if (!sa->qgroupid) {
4852 		ret = -EINVAL;
4853 		goto out;
4854 	}
4855 
4856 	trans = btrfs_join_transaction(root);
4857 	if (IS_ERR(trans)) {
4858 		ret = PTR_ERR(trans);
4859 		goto out;
4860 	}
4861 
4862 	/* FIXME: check if the IDs really exist */
4863 	if (sa->create) {
4864 		ret = btrfs_create_qgroup(trans, root->fs_info, sa->qgroupid);
4865 	} else {
4866 		ret = btrfs_remove_qgroup(trans, root->fs_info, sa->qgroupid);
4867 	}
4868 
4869 	err = btrfs_end_transaction(trans, root);
4870 	if (err && !ret)
4871 		ret = err;
4872 
4873 out:
4874 	kfree(sa);
4875 drop_write:
4876 	mnt_drop_write_file(file);
4877 	return ret;
4878 }
4879 
4880 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
4881 {
4882 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4883 	struct btrfs_ioctl_qgroup_limit_args *sa;
4884 	struct btrfs_trans_handle *trans;
4885 	int ret;
4886 	int err;
4887 	u64 qgroupid;
4888 
4889 	if (!capable(CAP_SYS_ADMIN))
4890 		return -EPERM;
4891 
4892 	ret = mnt_want_write_file(file);
4893 	if (ret)
4894 		return ret;
4895 
4896 	sa = memdup_user(arg, sizeof(*sa));
4897 	if (IS_ERR(sa)) {
4898 		ret = PTR_ERR(sa);
4899 		goto drop_write;
4900 	}
4901 
4902 	trans = btrfs_join_transaction(root);
4903 	if (IS_ERR(trans)) {
4904 		ret = PTR_ERR(trans);
4905 		goto out;
4906 	}
4907 
4908 	qgroupid = sa->qgroupid;
4909 	if (!qgroupid) {
4910 		/* take the current subvol as qgroup */
4911 		qgroupid = root->root_key.objectid;
4912 	}
4913 
4914 	/* FIXME: check if the IDs really exist */
4915 	ret = btrfs_limit_qgroup(trans, root->fs_info, qgroupid, &sa->lim);
4916 
4917 	err = btrfs_end_transaction(trans, root);
4918 	if (err && !ret)
4919 		ret = err;
4920 
4921 out:
4922 	kfree(sa);
4923 drop_write:
4924 	mnt_drop_write_file(file);
4925 	return ret;
4926 }
4927 
4928 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
4929 {
4930 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4931 	struct btrfs_ioctl_quota_rescan_args *qsa;
4932 	int ret;
4933 
4934 	if (!capable(CAP_SYS_ADMIN))
4935 		return -EPERM;
4936 
4937 	ret = mnt_want_write_file(file);
4938 	if (ret)
4939 		return ret;
4940 
4941 	qsa = memdup_user(arg, sizeof(*qsa));
4942 	if (IS_ERR(qsa)) {
4943 		ret = PTR_ERR(qsa);
4944 		goto drop_write;
4945 	}
4946 
4947 	if (qsa->flags) {
4948 		ret = -EINVAL;
4949 		goto out;
4950 	}
4951 
4952 	ret = btrfs_qgroup_rescan(root->fs_info);
4953 
4954 out:
4955 	kfree(qsa);
4956 drop_write:
4957 	mnt_drop_write_file(file);
4958 	return ret;
4959 }
4960 
4961 static long btrfs_ioctl_quota_rescan_status(struct file *file, void __user *arg)
4962 {
4963 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4964 	struct btrfs_ioctl_quota_rescan_args *qsa;
4965 	int ret = 0;
4966 
4967 	if (!capable(CAP_SYS_ADMIN))
4968 		return -EPERM;
4969 
4970 	qsa = kzalloc(sizeof(*qsa), GFP_NOFS);
4971 	if (!qsa)
4972 		return -ENOMEM;
4973 
4974 	if (root->fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
4975 		qsa->flags = 1;
4976 		qsa->progress = root->fs_info->qgroup_rescan_progress.objectid;
4977 	}
4978 
4979 	if (copy_to_user(arg, qsa, sizeof(*qsa)))
4980 		ret = -EFAULT;
4981 
4982 	kfree(qsa);
4983 	return ret;
4984 }
4985 
4986 static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg)
4987 {
4988 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4989 
4990 	if (!capable(CAP_SYS_ADMIN))
4991 		return -EPERM;
4992 
4993 	return btrfs_qgroup_wait_for_completion(root->fs_info);
4994 }
4995 
4996 static long _btrfs_ioctl_set_received_subvol(struct file *file,
4997 					    struct btrfs_ioctl_received_subvol_args *sa)
4998 {
4999 	struct inode *inode = file_inode(file);
5000 	struct btrfs_root *root = BTRFS_I(inode)->root;
5001 	struct btrfs_root_item *root_item = &root->root_item;
5002 	struct btrfs_trans_handle *trans;
5003 	struct timespec ct = CURRENT_TIME;
5004 	int ret = 0;
5005 	int received_uuid_changed;
5006 
5007 	if (!inode_owner_or_capable(inode))
5008 		return -EPERM;
5009 
5010 	ret = mnt_want_write_file(file);
5011 	if (ret < 0)
5012 		return ret;
5013 
5014 	down_write(&root->fs_info->subvol_sem);
5015 
5016 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
5017 		ret = -EINVAL;
5018 		goto out;
5019 	}
5020 
5021 	if (btrfs_root_readonly(root)) {
5022 		ret = -EROFS;
5023 		goto out;
5024 	}
5025 
5026 	/*
5027 	 * 1 - root item
5028 	 * 2 - uuid items (received uuid + subvol uuid)
5029 	 */
5030 	trans = btrfs_start_transaction(root, 3);
5031 	if (IS_ERR(trans)) {
5032 		ret = PTR_ERR(trans);
5033 		trans = NULL;
5034 		goto out;
5035 	}
5036 
5037 	sa->rtransid = trans->transid;
5038 	sa->rtime.sec = ct.tv_sec;
5039 	sa->rtime.nsec = ct.tv_nsec;
5040 
5041 	received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
5042 				       BTRFS_UUID_SIZE);
5043 	if (received_uuid_changed &&
5044 	    !btrfs_is_empty_uuid(root_item->received_uuid))
5045 		btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
5046 				    root_item->received_uuid,
5047 				    BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5048 				    root->root_key.objectid);
5049 	memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
5050 	btrfs_set_root_stransid(root_item, sa->stransid);
5051 	btrfs_set_root_rtransid(root_item, sa->rtransid);
5052 	btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
5053 	btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
5054 	btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
5055 	btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
5056 
5057 	ret = btrfs_update_root(trans, root->fs_info->tree_root,
5058 				&root->root_key, &root->root_item);
5059 	if (ret < 0) {
5060 		btrfs_end_transaction(trans, root);
5061 		goto out;
5062 	}
5063 	if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
5064 		ret = btrfs_uuid_tree_add(trans, root->fs_info->uuid_root,
5065 					  sa->uuid,
5066 					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5067 					  root->root_key.objectid);
5068 		if (ret < 0 && ret != -EEXIST) {
5069 			btrfs_abort_transaction(trans, root, ret);
5070 			goto out;
5071 		}
5072 	}
5073 	ret = btrfs_commit_transaction(trans, root);
5074 	if (ret < 0) {
5075 		btrfs_abort_transaction(trans, root, ret);
5076 		goto out;
5077 	}
5078 
5079 out:
5080 	up_write(&root->fs_info->subvol_sem);
5081 	mnt_drop_write_file(file);
5082 	return ret;
5083 }
5084 
5085 #ifdef CONFIG_64BIT
5086 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
5087 						void __user *arg)
5088 {
5089 	struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
5090 	struct btrfs_ioctl_received_subvol_args *args64 = NULL;
5091 	int ret = 0;
5092 
5093 	args32 = memdup_user(arg, sizeof(*args32));
5094 	if (IS_ERR(args32)) {
5095 		ret = PTR_ERR(args32);
5096 		args32 = NULL;
5097 		goto out;
5098 	}
5099 
5100 	args64 = kmalloc(sizeof(*args64), GFP_NOFS);
5101 	if (!args64) {
5102 		ret = -ENOMEM;
5103 		goto out;
5104 	}
5105 
5106 	memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
5107 	args64->stransid = args32->stransid;
5108 	args64->rtransid = args32->rtransid;
5109 	args64->stime.sec = args32->stime.sec;
5110 	args64->stime.nsec = args32->stime.nsec;
5111 	args64->rtime.sec = args32->rtime.sec;
5112 	args64->rtime.nsec = args32->rtime.nsec;
5113 	args64->flags = args32->flags;
5114 
5115 	ret = _btrfs_ioctl_set_received_subvol(file, args64);
5116 	if (ret)
5117 		goto out;
5118 
5119 	memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
5120 	args32->stransid = args64->stransid;
5121 	args32->rtransid = args64->rtransid;
5122 	args32->stime.sec = args64->stime.sec;
5123 	args32->stime.nsec = args64->stime.nsec;
5124 	args32->rtime.sec = args64->rtime.sec;
5125 	args32->rtime.nsec = args64->rtime.nsec;
5126 	args32->flags = args64->flags;
5127 
5128 	ret = copy_to_user(arg, args32, sizeof(*args32));
5129 	if (ret)
5130 		ret = -EFAULT;
5131 
5132 out:
5133 	kfree(args32);
5134 	kfree(args64);
5135 	return ret;
5136 }
5137 #endif
5138 
5139 static long btrfs_ioctl_set_received_subvol(struct file *file,
5140 					    void __user *arg)
5141 {
5142 	struct btrfs_ioctl_received_subvol_args *sa = NULL;
5143 	int ret = 0;
5144 
5145 	sa = memdup_user(arg, sizeof(*sa));
5146 	if (IS_ERR(sa)) {
5147 		ret = PTR_ERR(sa);
5148 		sa = NULL;
5149 		goto out;
5150 	}
5151 
5152 	ret = _btrfs_ioctl_set_received_subvol(file, sa);
5153 
5154 	if (ret)
5155 		goto out;
5156 
5157 	ret = copy_to_user(arg, sa, sizeof(*sa));
5158 	if (ret)
5159 		ret = -EFAULT;
5160 
5161 out:
5162 	kfree(sa);
5163 	return ret;
5164 }
5165 
5166 static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
5167 {
5168 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
5169 	size_t len;
5170 	int ret;
5171 	char label[BTRFS_LABEL_SIZE];
5172 
5173 	spin_lock(&root->fs_info->super_lock);
5174 	memcpy(label, root->fs_info->super_copy->label, BTRFS_LABEL_SIZE);
5175 	spin_unlock(&root->fs_info->super_lock);
5176 
5177 	len = strnlen(label, BTRFS_LABEL_SIZE);
5178 
5179 	if (len == BTRFS_LABEL_SIZE) {
5180 		btrfs_warn(root->fs_info,
5181 			"label is too long, return the first %zu bytes", --len);
5182 	}
5183 
5184 	ret = copy_to_user(arg, label, len);
5185 
5186 	return ret ? -EFAULT : 0;
5187 }
5188 
5189 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
5190 {
5191 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
5192 	struct btrfs_super_block *super_block = root->fs_info->super_copy;
5193 	struct btrfs_trans_handle *trans;
5194 	char label[BTRFS_LABEL_SIZE];
5195 	int ret;
5196 
5197 	if (!capable(CAP_SYS_ADMIN))
5198 		return -EPERM;
5199 
5200 	if (copy_from_user(label, arg, sizeof(label)))
5201 		return -EFAULT;
5202 
5203 	if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
5204 		btrfs_err(root->fs_info, "unable to set label with more than %d bytes",
5205 		       BTRFS_LABEL_SIZE - 1);
5206 		return -EINVAL;
5207 	}
5208 
5209 	ret = mnt_want_write_file(file);
5210 	if (ret)
5211 		return ret;
5212 
5213 	trans = btrfs_start_transaction(root, 0);
5214 	if (IS_ERR(trans)) {
5215 		ret = PTR_ERR(trans);
5216 		goto out_unlock;
5217 	}
5218 
5219 	spin_lock(&root->fs_info->super_lock);
5220 	strcpy(super_block->label, label);
5221 	spin_unlock(&root->fs_info->super_lock);
5222 	ret = btrfs_commit_transaction(trans, root);
5223 
5224 out_unlock:
5225 	mnt_drop_write_file(file);
5226 	return ret;
5227 }
5228 
5229 #define INIT_FEATURE_FLAGS(suffix) \
5230 	{ .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
5231 	  .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
5232 	  .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
5233 
5234 static int btrfs_ioctl_get_supported_features(struct file *file,
5235 					      void __user *arg)
5236 {
5237 	static struct btrfs_ioctl_feature_flags features[3] = {
5238 		INIT_FEATURE_FLAGS(SUPP),
5239 		INIT_FEATURE_FLAGS(SAFE_SET),
5240 		INIT_FEATURE_FLAGS(SAFE_CLEAR)
5241 	};
5242 
5243 	if (copy_to_user(arg, &features, sizeof(features)))
5244 		return -EFAULT;
5245 
5246 	return 0;
5247 }
5248 
5249 static int btrfs_ioctl_get_features(struct file *file, void __user *arg)
5250 {
5251 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
5252 	struct btrfs_super_block *super_block = root->fs_info->super_copy;
5253 	struct btrfs_ioctl_feature_flags features;
5254 
5255 	features.compat_flags = btrfs_super_compat_flags(super_block);
5256 	features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
5257 	features.incompat_flags = btrfs_super_incompat_flags(super_block);
5258 
5259 	if (copy_to_user(arg, &features, sizeof(features)))
5260 		return -EFAULT;
5261 
5262 	return 0;
5263 }
5264 
5265 static int check_feature_bits(struct btrfs_root *root,
5266 			      enum btrfs_feature_set set,
5267 			      u64 change_mask, u64 flags, u64 supported_flags,
5268 			      u64 safe_set, u64 safe_clear)
5269 {
5270 	const char *type = btrfs_feature_set_names[set];
5271 	char *names;
5272 	u64 disallowed, unsupported;
5273 	u64 set_mask = flags & change_mask;
5274 	u64 clear_mask = ~flags & change_mask;
5275 
5276 	unsupported = set_mask & ~supported_flags;
5277 	if (unsupported) {
5278 		names = btrfs_printable_features(set, unsupported);
5279 		if (names) {
5280 			btrfs_warn(root->fs_info,
5281 			   "this kernel does not support the %s feature bit%s",
5282 			   names, strchr(names, ',') ? "s" : "");
5283 			kfree(names);
5284 		} else
5285 			btrfs_warn(root->fs_info,
5286 			   "this kernel does not support %s bits 0x%llx",
5287 			   type, unsupported);
5288 		return -EOPNOTSUPP;
5289 	}
5290 
5291 	disallowed = set_mask & ~safe_set;
5292 	if (disallowed) {
5293 		names = btrfs_printable_features(set, disallowed);
5294 		if (names) {
5295 			btrfs_warn(root->fs_info,
5296 			   "can't set the %s feature bit%s while mounted",
5297 			   names, strchr(names, ',') ? "s" : "");
5298 			kfree(names);
5299 		} else
5300 			btrfs_warn(root->fs_info,
5301 			   "can't set %s bits 0x%llx while mounted",
5302 			   type, disallowed);
5303 		return -EPERM;
5304 	}
5305 
5306 	disallowed = clear_mask & ~safe_clear;
5307 	if (disallowed) {
5308 		names = btrfs_printable_features(set, disallowed);
5309 		if (names) {
5310 			btrfs_warn(root->fs_info,
5311 			   "can't clear the %s feature bit%s while mounted",
5312 			   names, strchr(names, ',') ? "s" : "");
5313 			kfree(names);
5314 		} else
5315 			btrfs_warn(root->fs_info,
5316 			   "can't clear %s bits 0x%llx while mounted",
5317 			   type, disallowed);
5318 		return -EPERM;
5319 	}
5320 
5321 	return 0;
5322 }
5323 
5324 #define check_feature(root, change_mask, flags, mask_base)	\
5325 check_feature_bits(root, FEAT_##mask_base, change_mask, flags,	\
5326 		   BTRFS_FEATURE_ ## mask_base ## _SUPP,	\
5327 		   BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,	\
5328 		   BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
5329 
5330 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
5331 {
5332 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
5333 	struct btrfs_super_block *super_block = root->fs_info->super_copy;
5334 	struct btrfs_ioctl_feature_flags flags[2];
5335 	struct btrfs_trans_handle *trans;
5336 	u64 newflags;
5337 	int ret;
5338 
5339 	if (!capable(CAP_SYS_ADMIN))
5340 		return -EPERM;
5341 
5342 	if (copy_from_user(flags, arg, sizeof(flags)))
5343 		return -EFAULT;
5344 
5345 	/* Nothing to do */
5346 	if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
5347 	    !flags[0].incompat_flags)
5348 		return 0;
5349 
5350 	ret = check_feature(root, flags[0].compat_flags,
5351 			    flags[1].compat_flags, COMPAT);
5352 	if (ret)
5353 		return ret;
5354 
5355 	ret = check_feature(root, flags[0].compat_ro_flags,
5356 			    flags[1].compat_ro_flags, COMPAT_RO);
5357 	if (ret)
5358 		return ret;
5359 
5360 	ret = check_feature(root, flags[0].incompat_flags,
5361 			    flags[1].incompat_flags, INCOMPAT);
5362 	if (ret)
5363 		return ret;
5364 
5365 	trans = btrfs_start_transaction(root, 0);
5366 	if (IS_ERR(trans))
5367 		return PTR_ERR(trans);
5368 
5369 	spin_lock(&root->fs_info->super_lock);
5370 	newflags = btrfs_super_compat_flags(super_block);
5371 	newflags |= flags[0].compat_flags & flags[1].compat_flags;
5372 	newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
5373 	btrfs_set_super_compat_flags(super_block, newflags);
5374 
5375 	newflags = btrfs_super_compat_ro_flags(super_block);
5376 	newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
5377 	newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
5378 	btrfs_set_super_compat_ro_flags(super_block, newflags);
5379 
5380 	newflags = btrfs_super_incompat_flags(super_block);
5381 	newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
5382 	newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
5383 	btrfs_set_super_incompat_flags(super_block, newflags);
5384 	spin_unlock(&root->fs_info->super_lock);
5385 
5386 	return btrfs_commit_transaction(trans, root);
5387 }
5388 
5389 long btrfs_ioctl(struct file *file, unsigned int
5390 		cmd, unsigned long arg)
5391 {
5392 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
5393 	void __user *argp = (void __user *)arg;
5394 
5395 	switch (cmd) {
5396 	case FS_IOC_GETFLAGS:
5397 		return btrfs_ioctl_getflags(file, argp);
5398 	case FS_IOC_SETFLAGS:
5399 		return btrfs_ioctl_setflags(file, argp);
5400 	case FS_IOC_GETVERSION:
5401 		return btrfs_ioctl_getversion(file, argp);
5402 	case FITRIM:
5403 		return btrfs_ioctl_fitrim(file, argp);
5404 	case BTRFS_IOC_SNAP_CREATE:
5405 		return btrfs_ioctl_snap_create(file, argp, 0);
5406 	case BTRFS_IOC_SNAP_CREATE_V2:
5407 		return btrfs_ioctl_snap_create_v2(file, argp, 0);
5408 	case BTRFS_IOC_SUBVOL_CREATE:
5409 		return btrfs_ioctl_snap_create(file, argp, 1);
5410 	case BTRFS_IOC_SUBVOL_CREATE_V2:
5411 		return btrfs_ioctl_snap_create_v2(file, argp, 1);
5412 	case BTRFS_IOC_SNAP_DESTROY:
5413 		return btrfs_ioctl_snap_destroy(file, argp);
5414 	case BTRFS_IOC_SUBVOL_GETFLAGS:
5415 		return btrfs_ioctl_subvol_getflags(file, argp);
5416 	case BTRFS_IOC_SUBVOL_SETFLAGS:
5417 		return btrfs_ioctl_subvol_setflags(file, argp);
5418 	case BTRFS_IOC_DEFAULT_SUBVOL:
5419 		return btrfs_ioctl_default_subvol(file, argp);
5420 	case BTRFS_IOC_DEFRAG:
5421 		return btrfs_ioctl_defrag(file, NULL);
5422 	case BTRFS_IOC_DEFRAG_RANGE:
5423 		return btrfs_ioctl_defrag(file, argp);
5424 	case BTRFS_IOC_RESIZE:
5425 		return btrfs_ioctl_resize(file, argp);
5426 	case BTRFS_IOC_ADD_DEV:
5427 		return btrfs_ioctl_add_dev(root, argp);
5428 	case BTRFS_IOC_RM_DEV:
5429 		return btrfs_ioctl_rm_dev(file, argp);
5430 	case BTRFS_IOC_FS_INFO:
5431 		return btrfs_ioctl_fs_info(root, argp);
5432 	case BTRFS_IOC_DEV_INFO:
5433 		return btrfs_ioctl_dev_info(root, argp);
5434 	case BTRFS_IOC_BALANCE:
5435 		return btrfs_ioctl_balance(file, NULL);
5436 	case BTRFS_IOC_CLONE:
5437 		return btrfs_ioctl_clone(file, arg, 0, 0, 0);
5438 	case BTRFS_IOC_CLONE_RANGE:
5439 		return btrfs_ioctl_clone_range(file, argp);
5440 	case BTRFS_IOC_TRANS_START:
5441 		return btrfs_ioctl_trans_start(file);
5442 	case BTRFS_IOC_TRANS_END:
5443 		return btrfs_ioctl_trans_end(file);
5444 	case BTRFS_IOC_TREE_SEARCH:
5445 		return btrfs_ioctl_tree_search(file, argp);
5446 	case BTRFS_IOC_TREE_SEARCH_V2:
5447 		return btrfs_ioctl_tree_search_v2(file, argp);
5448 	case BTRFS_IOC_INO_LOOKUP:
5449 		return btrfs_ioctl_ino_lookup(file, argp);
5450 	case BTRFS_IOC_INO_PATHS:
5451 		return btrfs_ioctl_ino_to_path(root, argp);
5452 	case BTRFS_IOC_LOGICAL_INO:
5453 		return btrfs_ioctl_logical_to_ino(root, argp);
5454 	case BTRFS_IOC_SPACE_INFO:
5455 		return btrfs_ioctl_space_info(root, argp);
5456 	case BTRFS_IOC_SYNC: {
5457 		int ret;
5458 
5459 		ret = btrfs_start_delalloc_roots(root->fs_info, 0, -1);
5460 		if (ret)
5461 			return ret;
5462 		ret = btrfs_sync_fs(file_inode(file)->i_sb, 1);
5463 		/*
5464 		 * The transaction thread may want to do more work,
5465 		 * namely it pokes the cleaner ktread that will start
5466 		 * processing uncleaned subvols.
5467 		 */
5468 		wake_up_process(root->fs_info->transaction_kthread);
5469 		return ret;
5470 	}
5471 	case BTRFS_IOC_START_SYNC:
5472 		return btrfs_ioctl_start_sync(root, argp);
5473 	case BTRFS_IOC_WAIT_SYNC:
5474 		return btrfs_ioctl_wait_sync(root, argp);
5475 	case BTRFS_IOC_SCRUB:
5476 		return btrfs_ioctl_scrub(file, argp);
5477 	case BTRFS_IOC_SCRUB_CANCEL:
5478 		return btrfs_ioctl_scrub_cancel(root, argp);
5479 	case BTRFS_IOC_SCRUB_PROGRESS:
5480 		return btrfs_ioctl_scrub_progress(root, argp);
5481 	case BTRFS_IOC_BALANCE_V2:
5482 		return btrfs_ioctl_balance(file, argp);
5483 	case BTRFS_IOC_BALANCE_CTL:
5484 		return btrfs_ioctl_balance_ctl(root, arg);
5485 	case BTRFS_IOC_BALANCE_PROGRESS:
5486 		return btrfs_ioctl_balance_progress(root, argp);
5487 	case BTRFS_IOC_SET_RECEIVED_SUBVOL:
5488 		return btrfs_ioctl_set_received_subvol(file, argp);
5489 #ifdef CONFIG_64BIT
5490 	case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
5491 		return btrfs_ioctl_set_received_subvol_32(file, argp);
5492 #endif
5493 	case BTRFS_IOC_SEND:
5494 		return btrfs_ioctl_send(file, argp);
5495 	case BTRFS_IOC_GET_DEV_STATS:
5496 		return btrfs_ioctl_get_dev_stats(root, argp);
5497 	case BTRFS_IOC_QUOTA_CTL:
5498 		return btrfs_ioctl_quota_ctl(file, argp);
5499 	case BTRFS_IOC_QGROUP_ASSIGN:
5500 		return btrfs_ioctl_qgroup_assign(file, argp);
5501 	case BTRFS_IOC_QGROUP_CREATE:
5502 		return btrfs_ioctl_qgroup_create(file, argp);
5503 	case BTRFS_IOC_QGROUP_LIMIT:
5504 		return btrfs_ioctl_qgroup_limit(file, argp);
5505 	case BTRFS_IOC_QUOTA_RESCAN:
5506 		return btrfs_ioctl_quota_rescan(file, argp);
5507 	case BTRFS_IOC_QUOTA_RESCAN_STATUS:
5508 		return btrfs_ioctl_quota_rescan_status(file, argp);
5509 	case BTRFS_IOC_QUOTA_RESCAN_WAIT:
5510 		return btrfs_ioctl_quota_rescan_wait(file, argp);
5511 	case BTRFS_IOC_DEV_REPLACE:
5512 		return btrfs_ioctl_dev_replace(root, argp);
5513 	case BTRFS_IOC_GET_FSLABEL:
5514 		return btrfs_ioctl_get_fslabel(file, argp);
5515 	case BTRFS_IOC_SET_FSLABEL:
5516 		return btrfs_ioctl_set_fslabel(file, argp);
5517 	case BTRFS_IOC_FILE_EXTENT_SAME:
5518 		return btrfs_ioctl_file_extent_same(file, argp);
5519 	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
5520 		return btrfs_ioctl_get_supported_features(file, argp);
5521 	case BTRFS_IOC_GET_FEATURES:
5522 		return btrfs_ioctl_get_features(file, argp);
5523 	case BTRFS_IOC_SET_FEATURES:
5524 		return btrfs_ioctl_set_features(file, argp);
5525 	}
5526 
5527 	return -ENOTTY;
5528 }
5529