xref: /openbmc/linux/fs/btrfs/ioctl.c (revision 6189f1b0)
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 
1034 	/*
1035 	 * make sure that once we start defragging an extent, we keep on
1036 	 * defragging it
1037 	 */
1038 	if (start < *defrag_end)
1039 		return 1;
1040 
1041 	*skip = 0;
1042 
1043 	em = defrag_lookup_extent(inode, start);
1044 	if (!em)
1045 		return 0;
1046 
1047 	/* this will cover holes, and inline extents */
1048 	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1049 		ret = 0;
1050 		goto out;
1051 	}
1052 
1053 	next_mergeable = defrag_check_next_extent(inode, em);
1054 	/*
1055 	 * we hit a real extent, if it is big or the next extent is not a
1056 	 * real extent, don't bother defragging it
1057 	 */
1058 	if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1059 	    (em->len >= thresh || !next_mergeable))
1060 		ret = 0;
1061 out:
1062 	/*
1063 	 * last_len ends up being a counter of how many bytes we've defragged.
1064 	 * every time we choose not to defrag an extent, we reset *last_len
1065 	 * so that the next tiny extent will force a defrag.
1066 	 *
1067 	 * The end result of this is that tiny extents before a single big
1068 	 * extent will force at least part of that big extent to be defragged.
1069 	 */
1070 	if (ret) {
1071 		*defrag_end = extent_map_end(em);
1072 	} else {
1073 		*last_len = 0;
1074 		*skip = extent_map_end(em);
1075 		*defrag_end = 0;
1076 	}
1077 
1078 	free_extent_map(em);
1079 	return ret;
1080 }
1081 
1082 /*
1083  * it doesn't do much good to defrag one or two pages
1084  * at a time.  This pulls in a nice chunk of pages
1085  * to COW and defrag.
1086  *
1087  * It also makes sure the delalloc code has enough
1088  * dirty data to avoid making new small extents as part
1089  * of the defrag
1090  *
1091  * It's a good idea to start RA on this range
1092  * before calling this.
1093  */
1094 static int cluster_pages_for_defrag(struct inode *inode,
1095 				    struct page **pages,
1096 				    unsigned long start_index,
1097 				    unsigned long num_pages)
1098 {
1099 	unsigned long file_end;
1100 	u64 isize = i_size_read(inode);
1101 	u64 page_start;
1102 	u64 page_end;
1103 	u64 page_cnt;
1104 	int ret;
1105 	int i;
1106 	int i_done;
1107 	struct btrfs_ordered_extent *ordered;
1108 	struct extent_state *cached_state = NULL;
1109 	struct extent_io_tree *tree;
1110 	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1111 
1112 	file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
1113 	if (!isize || start_index > file_end)
1114 		return 0;
1115 
1116 	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1117 
1118 	ret = btrfs_delalloc_reserve_space(inode,
1119 					   page_cnt << PAGE_CACHE_SHIFT);
1120 	if (ret)
1121 		return ret;
1122 	i_done = 0;
1123 	tree = &BTRFS_I(inode)->io_tree;
1124 
1125 	/* step one, lock all the pages */
1126 	for (i = 0; i < page_cnt; i++) {
1127 		struct page *page;
1128 again:
1129 		page = find_or_create_page(inode->i_mapping,
1130 					   start_index + i, mask);
1131 		if (!page)
1132 			break;
1133 
1134 		page_start = page_offset(page);
1135 		page_end = page_start + PAGE_CACHE_SIZE - 1;
1136 		while (1) {
1137 			lock_extent_bits(tree, page_start, page_end,
1138 					 0, &cached_state);
1139 			ordered = btrfs_lookup_ordered_extent(inode,
1140 							      page_start);
1141 			unlock_extent_cached(tree, page_start, page_end,
1142 					     &cached_state, GFP_NOFS);
1143 			if (!ordered)
1144 				break;
1145 
1146 			unlock_page(page);
1147 			btrfs_start_ordered_extent(inode, ordered, 1);
1148 			btrfs_put_ordered_extent(ordered);
1149 			lock_page(page);
1150 			/*
1151 			 * we unlocked the page above, so we need check if
1152 			 * it was released or not.
1153 			 */
1154 			if (page->mapping != inode->i_mapping) {
1155 				unlock_page(page);
1156 				page_cache_release(page);
1157 				goto again;
1158 			}
1159 		}
1160 
1161 		if (!PageUptodate(page)) {
1162 			btrfs_readpage(NULL, page);
1163 			lock_page(page);
1164 			if (!PageUptodate(page)) {
1165 				unlock_page(page);
1166 				page_cache_release(page);
1167 				ret = -EIO;
1168 				break;
1169 			}
1170 		}
1171 
1172 		if (page->mapping != inode->i_mapping) {
1173 			unlock_page(page);
1174 			page_cache_release(page);
1175 			goto again;
1176 		}
1177 
1178 		pages[i] = page;
1179 		i_done++;
1180 	}
1181 	if (!i_done || ret)
1182 		goto out;
1183 
1184 	if (!(inode->i_sb->s_flags & MS_ACTIVE))
1185 		goto out;
1186 
1187 	/*
1188 	 * so now we have a nice long stream of locked
1189 	 * and up to date pages, lets wait on them
1190 	 */
1191 	for (i = 0; i < i_done; i++)
1192 		wait_on_page_writeback(pages[i]);
1193 
1194 	page_start = page_offset(pages[0]);
1195 	page_end = page_offset(pages[i_done - 1]) + PAGE_CACHE_SIZE;
1196 
1197 	lock_extent_bits(&BTRFS_I(inode)->io_tree,
1198 			 page_start, page_end - 1, 0, &cached_state);
1199 	clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1200 			  page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1201 			  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1202 			  &cached_state, GFP_NOFS);
1203 
1204 	if (i_done != page_cnt) {
1205 		spin_lock(&BTRFS_I(inode)->lock);
1206 		BTRFS_I(inode)->outstanding_extents++;
1207 		spin_unlock(&BTRFS_I(inode)->lock);
1208 		btrfs_delalloc_release_space(inode,
1209 				     (page_cnt - i_done) << PAGE_CACHE_SHIFT);
1210 	}
1211 
1212 
1213 	set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1214 			  &cached_state, GFP_NOFS);
1215 
1216 	unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1217 			     page_start, page_end - 1, &cached_state,
1218 			     GFP_NOFS);
1219 
1220 	for (i = 0; i < i_done; i++) {
1221 		clear_page_dirty_for_io(pages[i]);
1222 		ClearPageChecked(pages[i]);
1223 		set_page_extent_mapped(pages[i]);
1224 		set_page_dirty(pages[i]);
1225 		unlock_page(pages[i]);
1226 		page_cache_release(pages[i]);
1227 	}
1228 	return i_done;
1229 out:
1230 	for (i = 0; i < i_done; i++) {
1231 		unlock_page(pages[i]);
1232 		page_cache_release(pages[i]);
1233 	}
1234 	btrfs_delalloc_release_space(inode, page_cnt << PAGE_CACHE_SHIFT);
1235 	return ret;
1236 
1237 }
1238 
1239 int btrfs_defrag_file(struct inode *inode, struct file *file,
1240 		      struct btrfs_ioctl_defrag_range_args *range,
1241 		      u64 newer_than, unsigned long max_to_defrag)
1242 {
1243 	struct btrfs_root *root = BTRFS_I(inode)->root;
1244 	struct file_ra_state *ra = NULL;
1245 	unsigned long last_index;
1246 	u64 isize = i_size_read(inode);
1247 	u64 last_len = 0;
1248 	u64 skip = 0;
1249 	u64 defrag_end = 0;
1250 	u64 newer_off = range->start;
1251 	unsigned long i;
1252 	unsigned long ra_index = 0;
1253 	int ret;
1254 	int defrag_count = 0;
1255 	int compress_type = BTRFS_COMPRESS_ZLIB;
1256 	u32 extent_thresh = range->extent_thresh;
1257 	unsigned long max_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
1258 	unsigned long cluster = max_cluster;
1259 	u64 new_align = ~((u64)128 * 1024 - 1);
1260 	struct page **pages = NULL;
1261 
1262 	if (isize == 0)
1263 		return 0;
1264 
1265 	if (range->start >= isize)
1266 		return -EINVAL;
1267 
1268 	if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1269 		if (range->compress_type > BTRFS_COMPRESS_TYPES)
1270 			return -EINVAL;
1271 		if (range->compress_type)
1272 			compress_type = range->compress_type;
1273 	}
1274 
1275 	if (extent_thresh == 0)
1276 		extent_thresh = 256 * 1024;
1277 
1278 	/*
1279 	 * if we were not given a file, allocate a readahead
1280 	 * context
1281 	 */
1282 	if (!file) {
1283 		ra = kzalloc(sizeof(*ra), GFP_NOFS);
1284 		if (!ra)
1285 			return -ENOMEM;
1286 		file_ra_state_init(ra, inode->i_mapping);
1287 	} else {
1288 		ra = &file->f_ra;
1289 	}
1290 
1291 	pages = kmalloc_array(max_cluster, sizeof(struct page *),
1292 			GFP_NOFS);
1293 	if (!pages) {
1294 		ret = -ENOMEM;
1295 		goto out_ra;
1296 	}
1297 
1298 	/* find the last page to defrag */
1299 	if (range->start + range->len > range->start) {
1300 		last_index = min_t(u64, isize - 1,
1301 			 range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
1302 	} else {
1303 		last_index = (isize - 1) >> PAGE_CACHE_SHIFT;
1304 	}
1305 
1306 	if (newer_than) {
1307 		ret = find_new_extents(root, inode, newer_than,
1308 				       &newer_off, 64 * 1024);
1309 		if (!ret) {
1310 			range->start = newer_off;
1311 			/*
1312 			 * we always align our defrag to help keep
1313 			 * the extents in the file evenly spaced
1314 			 */
1315 			i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1316 		} else
1317 			goto out_ra;
1318 	} else {
1319 		i = range->start >> PAGE_CACHE_SHIFT;
1320 	}
1321 	if (!max_to_defrag)
1322 		max_to_defrag = last_index - i + 1;
1323 
1324 	/*
1325 	 * make writeback starts from i, so the defrag range can be
1326 	 * written sequentially.
1327 	 */
1328 	if (i < inode->i_mapping->writeback_index)
1329 		inode->i_mapping->writeback_index = i;
1330 
1331 	while (i <= last_index && defrag_count < max_to_defrag &&
1332 	       (i < DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE))) {
1333 		/*
1334 		 * make sure we stop running if someone unmounts
1335 		 * the FS
1336 		 */
1337 		if (!(inode->i_sb->s_flags & MS_ACTIVE))
1338 			break;
1339 
1340 		if (btrfs_defrag_cancelled(root->fs_info)) {
1341 			printk(KERN_DEBUG "BTRFS: defrag_file cancelled\n");
1342 			ret = -EAGAIN;
1343 			break;
1344 		}
1345 
1346 		if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
1347 					 extent_thresh, &last_len, &skip,
1348 					 &defrag_end, range->flags &
1349 					 BTRFS_DEFRAG_RANGE_COMPRESS)) {
1350 			unsigned long next;
1351 			/*
1352 			 * the should_defrag function tells us how much to skip
1353 			 * bump our counter by the suggested amount
1354 			 */
1355 			next = DIV_ROUND_UP(skip, PAGE_CACHE_SIZE);
1356 			i = max(i + 1, next);
1357 			continue;
1358 		}
1359 
1360 		if (!newer_than) {
1361 			cluster = (PAGE_CACHE_ALIGN(defrag_end) >>
1362 				   PAGE_CACHE_SHIFT) - i;
1363 			cluster = min(cluster, max_cluster);
1364 		} else {
1365 			cluster = max_cluster;
1366 		}
1367 
1368 		if (i + cluster > ra_index) {
1369 			ra_index = max(i, ra_index);
1370 			btrfs_force_ra(inode->i_mapping, ra, file, ra_index,
1371 				       cluster);
1372 			ra_index += cluster;
1373 		}
1374 
1375 		mutex_lock(&inode->i_mutex);
1376 		if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
1377 			BTRFS_I(inode)->force_compress = compress_type;
1378 		ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1379 		if (ret < 0) {
1380 			mutex_unlock(&inode->i_mutex);
1381 			goto out_ra;
1382 		}
1383 
1384 		defrag_count += ret;
1385 		balance_dirty_pages_ratelimited(inode->i_mapping);
1386 		mutex_unlock(&inode->i_mutex);
1387 
1388 		if (newer_than) {
1389 			if (newer_off == (u64)-1)
1390 				break;
1391 
1392 			if (ret > 0)
1393 				i += ret;
1394 
1395 			newer_off = max(newer_off + 1,
1396 					(u64)i << PAGE_CACHE_SHIFT);
1397 
1398 			ret = find_new_extents(root, inode,
1399 					       newer_than, &newer_off,
1400 					       64 * 1024);
1401 			if (!ret) {
1402 				range->start = newer_off;
1403 				i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1404 			} else {
1405 				break;
1406 			}
1407 		} else {
1408 			if (ret > 0) {
1409 				i += ret;
1410 				last_len += ret << PAGE_CACHE_SHIFT;
1411 			} else {
1412 				i++;
1413 				last_len = 0;
1414 			}
1415 		}
1416 	}
1417 
1418 	if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1419 		filemap_flush(inode->i_mapping);
1420 		if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1421 			     &BTRFS_I(inode)->runtime_flags))
1422 			filemap_flush(inode->i_mapping);
1423 	}
1424 
1425 	if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1426 		/* the filemap_flush will queue IO into the worker threads, but
1427 		 * we have to make sure the IO is actually started and that
1428 		 * ordered extents get created before we return
1429 		 */
1430 		atomic_inc(&root->fs_info->async_submit_draining);
1431 		while (atomic_read(&root->fs_info->nr_async_submits) ||
1432 		      atomic_read(&root->fs_info->async_delalloc_pages)) {
1433 			wait_event(root->fs_info->async_submit_wait,
1434 			   (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
1435 			    atomic_read(&root->fs_info->async_delalloc_pages) == 0));
1436 		}
1437 		atomic_dec(&root->fs_info->async_submit_draining);
1438 	}
1439 
1440 	if (range->compress_type == BTRFS_COMPRESS_LZO) {
1441 		btrfs_set_fs_incompat(root->fs_info, COMPRESS_LZO);
1442 	}
1443 
1444 	ret = defrag_count;
1445 
1446 out_ra:
1447 	if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1448 		mutex_lock(&inode->i_mutex);
1449 		BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
1450 		mutex_unlock(&inode->i_mutex);
1451 	}
1452 	if (!file)
1453 		kfree(ra);
1454 	kfree(pages);
1455 	return ret;
1456 }
1457 
1458 static noinline int btrfs_ioctl_resize(struct file *file,
1459 					void __user *arg)
1460 {
1461 	u64 new_size;
1462 	u64 old_size;
1463 	u64 devid = 1;
1464 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
1465 	struct btrfs_ioctl_vol_args *vol_args;
1466 	struct btrfs_trans_handle *trans;
1467 	struct btrfs_device *device = NULL;
1468 	char *sizestr;
1469 	char *retptr;
1470 	char *devstr = NULL;
1471 	int ret = 0;
1472 	int mod = 0;
1473 
1474 	if (!capable(CAP_SYS_ADMIN))
1475 		return -EPERM;
1476 
1477 	ret = mnt_want_write_file(file);
1478 	if (ret)
1479 		return ret;
1480 
1481 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1482 			1)) {
1483 		mnt_drop_write_file(file);
1484 		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1485 	}
1486 
1487 	mutex_lock(&root->fs_info->volume_mutex);
1488 	vol_args = memdup_user(arg, sizeof(*vol_args));
1489 	if (IS_ERR(vol_args)) {
1490 		ret = PTR_ERR(vol_args);
1491 		goto out;
1492 	}
1493 
1494 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1495 
1496 	sizestr = vol_args->name;
1497 	devstr = strchr(sizestr, ':');
1498 	if (devstr) {
1499 		sizestr = devstr + 1;
1500 		*devstr = '\0';
1501 		devstr = vol_args->name;
1502 		ret = kstrtoull(devstr, 10, &devid);
1503 		if (ret)
1504 			goto out_free;
1505 		if (!devid) {
1506 			ret = -EINVAL;
1507 			goto out_free;
1508 		}
1509 		btrfs_info(root->fs_info, "resizing devid %llu", devid);
1510 	}
1511 
1512 	device = btrfs_find_device(root->fs_info, devid, NULL, NULL);
1513 	if (!device) {
1514 		btrfs_info(root->fs_info, "resizer unable to find device %llu",
1515 		       devid);
1516 		ret = -ENODEV;
1517 		goto out_free;
1518 	}
1519 
1520 	if (!device->writeable) {
1521 		btrfs_info(root->fs_info,
1522 			   "resizer unable to apply on readonly device %llu",
1523 		       devid);
1524 		ret = -EPERM;
1525 		goto out_free;
1526 	}
1527 
1528 	if (!strcmp(sizestr, "max"))
1529 		new_size = device->bdev->bd_inode->i_size;
1530 	else {
1531 		if (sizestr[0] == '-') {
1532 			mod = -1;
1533 			sizestr++;
1534 		} else if (sizestr[0] == '+') {
1535 			mod = 1;
1536 			sizestr++;
1537 		}
1538 		new_size = memparse(sizestr, &retptr);
1539 		if (*retptr != '\0' || new_size == 0) {
1540 			ret = -EINVAL;
1541 			goto out_free;
1542 		}
1543 	}
1544 
1545 	if (device->is_tgtdev_for_dev_replace) {
1546 		ret = -EPERM;
1547 		goto out_free;
1548 	}
1549 
1550 	old_size = btrfs_device_get_total_bytes(device);
1551 
1552 	if (mod < 0) {
1553 		if (new_size > old_size) {
1554 			ret = -EINVAL;
1555 			goto out_free;
1556 		}
1557 		new_size = old_size - new_size;
1558 	} else if (mod > 0) {
1559 		if (new_size > ULLONG_MAX - old_size) {
1560 			ret = -ERANGE;
1561 			goto out_free;
1562 		}
1563 		new_size = old_size + new_size;
1564 	}
1565 
1566 	if (new_size < 256 * 1024 * 1024) {
1567 		ret = -EINVAL;
1568 		goto out_free;
1569 	}
1570 	if (new_size > device->bdev->bd_inode->i_size) {
1571 		ret = -EFBIG;
1572 		goto out_free;
1573 	}
1574 
1575 	new_size = div_u64(new_size, root->sectorsize);
1576 	new_size *= root->sectorsize;
1577 
1578 	printk_in_rcu(KERN_INFO "BTRFS: new size for %s is %llu\n",
1579 		      rcu_str_deref(device->name), new_size);
1580 
1581 	if (new_size > old_size) {
1582 		trans = btrfs_start_transaction(root, 0);
1583 		if (IS_ERR(trans)) {
1584 			ret = PTR_ERR(trans);
1585 			goto out_free;
1586 		}
1587 		ret = btrfs_grow_device(trans, device, new_size);
1588 		btrfs_commit_transaction(trans, root);
1589 	} else if (new_size < old_size) {
1590 		ret = btrfs_shrink_device(device, new_size);
1591 	} /* equal, nothing need to do */
1592 
1593 out_free:
1594 	kfree(vol_args);
1595 out:
1596 	mutex_unlock(&root->fs_info->volume_mutex);
1597 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
1598 	mnt_drop_write_file(file);
1599 	return ret;
1600 }
1601 
1602 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1603 				char *name, unsigned long fd, int subvol,
1604 				u64 *transid, bool readonly,
1605 				struct btrfs_qgroup_inherit *inherit)
1606 {
1607 	int namelen;
1608 	int ret = 0;
1609 
1610 	ret = mnt_want_write_file(file);
1611 	if (ret)
1612 		goto out;
1613 
1614 	namelen = strlen(name);
1615 	if (strchr(name, '/')) {
1616 		ret = -EINVAL;
1617 		goto out_drop_write;
1618 	}
1619 
1620 	if (name[0] == '.' &&
1621 	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1622 		ret = -EEXIST;
1623 		goto out_drop_write;
1624 	}
1625 
1626 	if (subvol) {
1627 		ret = btrfs_mksubvol(&file->f_path, name, namelen,
1628 				     NULL, transid, readonly, inherit);
1629 	} else {
1630 		struct fd src = fdget(fd);
1631 		struct inode *src_inode;
1632 		if (!src.file) {
1633 			ret = -EINVAL;
1634 			goto out_drop_write;
1635 		}
1636 
1637 		src_inode = file_inode(src.file);
1638 		if (src_inode->i_sb != file_inode(file)->i_sb) {
1639 			btrfs_info(BTRFS_I(src_inode)->root->fs_info,
1640 				   "Snapshot src from another FS");
1641 			ret = -EXDEV;
1642 		} else if (!inode_owner_or_capable(src_inode)) {
1643 			/*
1644 			 * Subvolume creation is not restricted, but snapshots
1645 			 * are limited to own subvolumes only
1646 			 */
1647 			ret = -EPERM;
1648 		} else {
1649 			ret = btrfs_mksubvol(&file->f_path, name, namelen,
1650 					     BTRFS_I(src_inode)->root,
1651 					     transid, readonly, inherit);
1652 		}
1653 		fdput(src);
1654 	}
1655 out_drop_write:
1656 	mnt_drop_write_file(file);
1657 out:
1658 	return ret;
1659 }
1660 
1661 static noinline int btrfs_ioctl_snap_create(struct file *file,
1662 					    void __user *arg, int subvol)
1663 {
1664 	struct btrfs_ioctl_vol_args *vol_args;
1665 	int ret;
1666 
1667 	vol_args = memdup_user(arg, sizeof(*vol_args));
1668 	if (IS_ERR(vol_args))
1669 		return PTR_ERR(vol_args);
1670 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1671 
1672 	ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1673 					      vol_args->fd, subvol,
1674 					      NULL, false, NULL);
1675 
1676 	kfree(vol_args);
1677 	return ret;
1678 }
1679 
1680 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1681 					       void __user *arg, int subvol)
1682 {
1683 	struct btrfs_ioctl_vol_args_v2 *vol_args;
1684 	int ret;
1685 	u64 transid = 0;
1686 	u64 *ptr = NULL;
1687 	bool readonly = false;
1688 	struct btrfs_qgroup_inherit *inherit = NULL;
1689 
1690 	vol_args = memdup_user(arg, sizeof(*vol_args));
1691 	if (IS_ERR(vol_args))
1692 		return PTR_ERR(vol_args);
1693 	vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1694 
1695 	if (vol_args->flags &
1696 	    ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
1697 	      BTRFS_SUBVOL_QGROUP_INHERIT)) {
1698 		ret = -EOPNOTSUPP;
1699 		goto free_args;
1700 	}
1701 
1702 	if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
1703 		ptr = &transid;
1704 	if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1705 		readonly = true;
1706 	if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1707 		if (vol_args->size > PAGE_CACHE_SIZE) {
1708 			ret = -EINVAL;
1709 			goto free_args;
1710 		}
1711 		inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1712 		if (IS_ERR(inherit)) {
1713 			ret = PTR_ERR(inherit);
1714 			goto free_args;
1715 		}
1716 	}
1717 
1718 	ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1719 					      vol_args->fd, subvol, ptr,
1720 					      readonly, inherit);
1721 	if (ret)
1722 		goto free_inherit;
1723 
1724 	if (ptr && copy_to_user(arg +
1725 				offsetof(struct btrfs_ioctl_vol_args_v2,
1726 					transid),
1727 				ptr, sizeof(*ptr)))
1728 		ret = -EFAULT;
1729 
1730 free_inherit:
1731 	kfree(inherit);
1732 free_args:
1733 	kfree(vol_args);
1734 	return ret;
1735 }
1736 
1737 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1738 						void __user *arg)
1739 {
1740 	struct inode *inode = file_inode(file);
1741 	struct btrfs_root *root = BTRFS_I(inode)->root;
1742 	int ret = 0;
1743 	u64 flags = 0;
1744 
1745 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID)
1746 		return -EINVAL;
1747 
1748 	down_read(&root->fs_info->subvol_sem);
1749 	if (btrfs_root_readonly(root))
1750 		flags |= BTRFS_SUBVOL_RDONLY;
1751 	up_read(&root->fs_info->subvol_sem);
1752 
1753 	if (copy_to_user(arg, &flags, sizeof(flags)))
1754 		ret = -EFAULT;
1755 
1756 	return ret;
1757 }
1758 
1759 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1760 					      void __user *arg)
1761 {
1762 	struct inode *inode = file_inode(file);
1763 	struct btrfs_root *root = BTRFS_I(inode)->root;
1764 	struct btrfs_trans_handle *trans;
1765 	u64 root_flags;
1766 	u64 flags;
1767 	int ret = 0;
1768 
1769 	if (!inode_owner_or_capable(inode))
1770 		return -EPERM;
1771 
1772 	ret = mnt_want_write_file(file);
1773 	if (ret)
1774 		goto out;
1775 
1776 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
1777 		ret = -EINVAL;
1778 		goto out_drop_write;
1779 	}
1780 
1781 	if (copy_from_user(&flags, arg, sizeof(flags))) {
1782 		ret = -EFAULT;
1783 		goto out_drop_write;
1784 	}
1785 
1786 	if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1787 		ret = -EINVAL;
1788 		goto out_drop_write;
1789 	}
1790 
1791 	if (flags & ~BTRFS_SUBVOL_RDONLY) {
1792 		ret = -EOPNOTSUPP;
1793 		goto out_drop_write;
1794 	}
1795 
1796 	down_write(&root->fs_info->subvol_sem);
1797 
1798 	/* nothing to do */
1799 	if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1800 		goto out_drop_sem;
1801 
1802 	root_flags = btrfs_root_flags(&root->root_item);
1803 	if (flags & BTRFS_SUBVOL_RDONLY) {
1804 		btrfs_set_root_flags(&root->root_item,
1805 				     root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1806 	} else {
1807 		/*
1808 		 * Block RO -> RW transition if this subvolume is involved in
1809 		 * send
1810 		 */
1811 		spin_lock(&root->root_item_lock);
1812 		if (root->send_in_progress == 0) {
1813 			btrfs_set_root_flags(&root->root_item,
1814 				     root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1815 			spin_unlock(&root->root_item_lock);
1816 		} else {
1817 			spin_unlock(&root->root_item_lock);
1818 			btrfs_warn(root->fs_info,
1819 			"Attempt to set subvolume %llu read-write during send",
1820 					root->root_key.objectid);
1821 			ret = -EPERM;
1822 			goto out_drop_sem;
1823 		}
1824 	}
1825 
1826 	trans = btrfs_start_transaction(root, 1);
1827 	if (IS_ERR(trans)) {
1828 		ret = PTR_ERR(trans);
1829 		goto out_reset;
1830 	}
1831 
1832 	ret = btrfs_update_root(trans, root->fs_info->tree_root,
1833 				&root->root_key, &root->root_item);
1834 
1835 	btrfs_commit_transaction(trans, root);
1836 out_reset:
1837 	if (ret)
1838 		btrfs_set_root_flags(&root->root_item, root_flags);
1839 out_drop_sem:
1840 	up_write(&root->fs_info->subvol_sem);
1841 out_drop_write:
1842 	mnt_drop_write_file(file);
1843 out:
1844 	return ret;
1845 }
1846 
1847 /*
1848  * helper to check if the subvolume references other subvolumes
1849  */
1850 static noinline int may_destroy_subvol(struct btrfs_root *root)
1851 {
1852 	struct btrfs_path *path;
1853 	struct btrfs_dir_item *di;
1854 	struct btrfs_key key;
1855 	u64 dir_id;
1856 	int ret;
1857 
1858 	path = btrfs_alloc_path();
1859 	if (!path)
1860 		return -ENOMEM;
1861 
1862 	/* Make sure this root isn't set as the default subvol */
1863 	dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
1864 	di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root, path,
1865 				   dir_id, "default", 7, 0);
1866 	if (di && !IS_ERR(di)) {
1867 		btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
1868 		if (key.objectid == root->root_key.objectid) {
1869 			ret = -EPERM;
1870 			btrfs_err(root->fs_info, "deleting default subvolume "
1871 				  "%llu is not allowed", key.objectid);
1872 			goto out;
1873 		}
1874 		btrfs_release_path(path);
1875 	}
1876 
1877 	key.objectid = root->root_key.objectid;
1878 	key.type = BTRFS_ROOT_REF_KEY;
1879 	key.offset = (u64)-1;
1880 
1881 	ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
1882 				&key, path, 0, 0);
1883 	if (ret < 0)
1884 		goto out;
1885 	BUG_ON(ret == 0);
1886 
1887 	ret = 0;
1888 	if (path->slots[0] > 0) {
1889 		path->slots[0]--;
1890 		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1891 		if (key.objectid == root->root_key.objectid &&
1892 		    key.type == BTRFS_ROOT_REF_KEY)
1893 			ret = -ENOTEMPTY;
1894 	}
1895 out:
1896 	btrfs_free_path(path);
1897 	return ret;
1898 }
1899 
1900 static noinline int key_in_sk(struct btrfs_key *key,
1901 			      struct btrfs_ioctl_search_key *sk)
1902 {
1903 	struct btrfs_key test;
1904 	int ret;
1905 
1906 	test.objectid = sk->min_objectid;
1907 	test.type = sk->min_type;
1908 	test.offset = sk->min_offset;
1909 
1910 	ret = btrfs_comp_cpu_keys(key, &test);
1911 	if (ret < 0)
1912 		return 0;
1913 
1914 	test.objectid = sk->max_objectid;
1915 	test.type = sk->max_type;
1916 	test.offset = sk->max_offset;
1917 
1918 	ret = btrfs_comp_cpu_keys(key, &test);
1919 	if (ret > 0)
1920 		return 0;
1921 	return 1;
1922 }
1923 
1924 static noinline int copy_to_sk(struct btrfs_root *root,
1925 			       struct btrfs_path *path,
1926 			       struct btrfs_key *key,
1927 			       struct btrfs_ioctl_search_key *sk,
1928 			       size_t *buf_size,
1929 			       char __user *ubuf,
1930 			       unsigned long *sk_offset,
1931 			       int *num_found)
1932 {
1933 	u64 found_transid;
1934 	struct extent_buffer *leaf;
1935 	struct btrfs_ioctl_search_header sh;
1936 	unsigned long item_off;
1937 	unsigned long item_len;
1938 	int nritems;
1939 	int i;
1940 	int slot;
1941 	int ret = 0;
1942 
1943 	leaf = path->nodes[0];
1944 	slot = path->slots[0];
1945 	nritems = btrfs_header_nritems(leaf);
1946 
1947 	if (btrfs_header_generation(leaf) > sk->max_transid) {
1948 		i = nritems;
1949 		goto advance_key;
1950 	}
1951 	found_transid = btrfs_header_generation(leaf);
1952 
1953 	for (i = slot; i < nritems; i++) {
1954 		item_off = btrfs_item_ptr_offset(leaf, i);
1955 		item_len = btrfs_item_size_nr(leaf, i);
1956 
1957 		btrfs_item_key_to_cpu(leaf, key, i);
1958 		if (!key_in_sk(key, sk))
1959 			continue;
1960 
1961 		if (sizeof(sh) + item_len > *buf_size) {
1962 			if (*num_found) {
1963 				ret = 1;
1964 				goto out;
1965 			}
1966 
1967 			/*
1968 			 * return one empty item back for v1, which does not
1969 			 * handle -EOVERFLOW
1970 			 */
1971 
1972 			*buf_size = sizeof(sh) + item_len;
1973 			item_len = 0;
1974 			ret = -EOVERFLOW;
1975 		}
1976 
1977 		if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
1978 			ret = 1;
1979 			goto out;
1980 		}
1981 
1982 		sh.objectid = key->objectid;
1983 		sh.offset = key->offset;
1984 		sh.type = key->type;
1985 		sh.len = item_len;
1986 		sh.transid = found_transid;
1987 
1988 		/* copy search result header */
1989 		if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
1990 			ret = -EFAULT;
1991 			goto out;
1992 		}
1993 
1994 		*sk_offset += sizeof(sh);
1995 
1996 		if (item_len) {
1997 			char __user *up = ubuf + *sk_offset;
1998 			/* copy the item */
1999 			if (read_extent_buffer_to_user(leaf, up,
2000 						       item_off, item_len)) {
2001 				ret = -EFAULT;
2002 				goto out;
2003 			}
2004 
2005 			*sk_offset += item_len;
2006 		}
2007 		(*num_found)++;
2008 
2009 		if (ret) /* -EOVERFLOW from above */
2010 			goto out;
2011 
2012 		if (*num_found >= sk->nr_items) {
2013 			ret = 1;
2014 			goto out;
2015 		}
2016 	}
2017 advance_key:
2018 	ret = 0;
2019 	if (key->offset < (u64)-1 && key->offset < sk->max_offset)
2020 		key->offset++;
2021 	else if (key->type < (u8)-1 && key->type < sk->max_type) {
2022 		key->offset = 0;
2023 		key->type++;
2024 	} else if (key->objectid < (u64)-1 && key->objectid < sk->max_objectid) {
2025 		key->offset = 0;
2026 		key->type = 0;
2027 		key->objectid++;
2028 	} else
2029 		ret = 1;
2030 out:
2031 	/*
2032 	 *  0: all items from this leaf copied, continue with next
2033 	 *  1: * more items can be copied, but unused buffer is too small
2034 	 *     * all items were found
2035 	 *     Either way, it will stops the loop which iterates to the next
2036 	 *     leaf
2037 	 *  -EOVERFLOW: item was to large for buffer
2038 	 *  -EFAULT: could not copy extent buffer back to userspace
2039 	 */
2040 	return ret;
2041 }
2042 
2043 static noinline int search_ioctl(struct inode *inode,
2044 				 struct btrfs_ioctl_search_key *sk,
2045 				 size_t *buf_size,
2046 				 char __user *ubuf)
2047 {
2048 	struct btrfs_root *root;
2049 	struct btrfs_key key;
2050 	struct btrfs_path *path;
2051 	struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
2052 	int ret;
2053 	int num_found = 0;
2054 	unsigned long sk_offset = 0;
2055 
2056 	if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
2057 		*buf_size = sizeof(struct btrfs_ioctl_search_header);
2058 		return -EOVERFLOW;
2059 	}
2060 
2061 	path = btrfs_alloc_path();
2062 	if (!path)
2063 		return -ENOMEM;
2064 
2065 	if (sk->tree_id == 0) {
2066 		/* search the root of the inode that was passed */
2067 		root = BTRFS_I(inode)->root;
2068 	} else {
2069 		key.objectid = sk->tree_id;
2070 		key.type = BTRFS_ROOT_ITEM_KEY;
2071 		key.offset = (u64)-1;
2072 		root = btrfs_read_fs_root_no_name(info, &key);
2073 		if (IS_ERR(root)) {
2074 			printk(KERN_ERR "BTRFS: could not find root %llu\n",
2075 			       sk->tree_id);
2076 			btrfs_free_path(path);
2077 			return -ENOENT;
2078 		}
2079 	}
2080 
2081 	key.objectid = sk->min_objectid;
2082 	key.type = sk->min_type;
2083 	key.offset = sk->min_offset;
2084 
2085 	while (1) {
2086 		ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2087 		if (ret != 0) {
2088 			if (ret > 0)
2089 				ret = 0;
2090 			goto err;
2091 		}
2092 		ret = copy_to_sk(root, path, &key, sk, buf_size, ubuf,
2093 				 &sk_offset, &num_found);
2094 		btrfs_release_path(path);
2095 		if (ret)
2096 			break;
2097 
2098 	}
2099 	if (ret > 0)
2100 		ret = 0;
2101 err:
2102 	sk->nr_items = num_found;
2103 	btrfs_free_path(path);
2104 	return ret;
2105 }
2106 
2107 static noinline int btrfs_ioctl_tree_search(struct file *file,
2108 					   void __user *argp)
2109 {
2110 	struct btrfs_ioctl_search_args __user *uargs;
2111 	struct btrfs_ioctl_search_key sk;
2112 	struct inode *inode;
2113 	int ret;
2114 	size_t buf_size;
2115 
2116 	if (!capable(CAP_SYS_ADMIN))
2117 		return -EPERM;
2118 
2119 	uargs = (struct btrfs_ioctl_search_args __user *)argp;
2120 
2121 	if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
2122 		return -EFAULT;
2123 
2124 	buf_size = sizeof(uargs->buf);
2125 
2126 	inode = file_inode(file);
2127 	ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
2128 
2129 	/*
2130 	 * In the origin implementation an overflow is handled by returning a
2131 	 * search header with a len of zero, so reset ret.
2132 	 */
2133 	if (ret == -EOVERFLOW)
2134 		ret = 0;
2135 
2136 	if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
2137 		ret = -EFAULT;
2138 	return ret;
2139 }
2140 
2141 static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
2142 					       void __user *argp)
2143 {
2144 	struct btrfs_ioctl_search_args_v2 __user *uarg;
2145 	struct btrfs_ioctl_search_args_v2 args;
2146 	struct inode *inode;
2147 	int ret;
2148 	size_t buf_size;
2149 	const size_t buf_limit = 16 * 1024 * 1024;
2150 
2151 	if (!capable(CAP_SYS_ADMIN))
2152 		return -EPERM;
2153 
2154 	/* copy search header and buffer size */
2155 	uarg = (struct btrfs_ioctl_search_args_v2 __user *)argp;
2156 	if (copy_from_user(&args, uarg, sizeof(args)))
2157 		return -EFAULT;
2158 
2159 	buf_size = args.buf_size;
2160 
2161 	if (buf_size < sizeof(struct btrfs_ioctl_search_header))
2162 		return -EOVERFLOW;
2163 
2164 	/* limit result size to 16MB */
2165 	if (buf_size > buf_limit)
2166 		buf_size = buf_limit;
2167 
2168 	inode = file_inode(file);
2169 	ret = search_ioctl(inode, &args.key, &buf_size,
2170 			   (char *)(&uarg->buf[0]));
2171 	if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
2172 		ret = -EFAULT;
2173 	else if (ret == -EOVERFLOW &&
2174 		copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
2175 		ret = -EFAULT;
2176 
2177 	return ret;
2178 }
2179 
2180 /*
2181  * Search INODE_REFs to identify path name of 'dirid' directory
2182  * in a 'tree_id' tree. and sets path name to 'name'.
2183  */
2184 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2185 				u64 tree_id, u64 dirid, char *name)
2186 {
2187 	struct btrfs_root *root;
2188 	struct btrfs_key key;
2189 	char *ptr;
2190 	int ret = -1;
2191 	int slot;
2192 	int len;
2193 	int total_len = 0;
2194 	struct btrfs_inode_ref *iref;
2195 	struct extent_buffer *l;
2196 	struct btrfs_path *path;
2197 
2198 	if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2199 		name[0]='\0';
2200 		return 0;
2201 	}
2202 
2203 	path = btrfs_alloc_path();
2204 	if (!path)
2205 		return -ENOMEM;
2206 
2207 	ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
2208 
2209 	key.objectid = tree_id;
2210 	key.type = BTRFS_ROOT_ITEM_KEY;
2211 	key.offset = (u64)-1;
2212 	root = btrfs_read_fs_root_no_name(info, &key);
2213 	if (IS_ERR(root)) {
2214 		printk(KERN_ERR "BTRFS: could not find root %llu\n", tree_id);
2215 		ret = -ENOENT;
2216 		goto out;
2217 	}
2218 
2219 	key.objectid = dirid;
2220 	key.type = BTRFS_INODE_REF_KEY;
2221 	key.offset = (u64)-1;
2222 
2223 	while (1) {
2224 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2225 		if (ret < 0)
2226 			goto out;
2227 		else if (ret > 0) {
2228 			ret = btrfs_previous_item(root, path, dirid,
2229 						  BTRFS_INODE_REF_KEY);
2230 			if (ret < 0)
2231 				goto out;
2232 			else if (ret > 0) {
2233 				ret = -ENOENT;
2234 				goto out;
2235 			}
2236 		}
2237 
2238 		l = path->nodes[0];
2239 		slot = path->slots[0];
2240 		btrfs_item_key_to_cpu(l, &key, slot);
2241 
2242 		iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2243 		len = btrfs_inode_ref_name_len(l, iref);
2244 		ptr -= len + 1;
2245 		total_len += len + 1;
2246 		if (ptr < name) {
2247 			ret = -ENAMETOOLONG;
2248 			goto out;
2249 		}
2250 
2251 		*(ptr + len) = '/';
2252 		read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2253 
2254 		if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2255 			break;
2256 
2257 		btrfs_release_path(path);
2258 		key.objectid = key.offset;
2259 		key.offset = (u64)-1;
2260 		dirid = key.objectid;
2261 	}
2262 	memmove(name, ptr, total_len);
2263 	name[total_len] = '\0';
2264 	ret = 0;
2265 out:
2266 	btrfs_free_path(path);
2267 	return ret;
2268 }
2269 
2270 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2271 					   void __user *argp)
2272 {
2273 	 struct btrfs_ioctl_ino_lookup_args *args;
2274 	 struct inode *inode;
2275 	int ret = 0;
2276 
2277 	args = memdup_user(argp, sizeof(*args));
2278 	if (IS_ERR(args))
2279 		return PTR_ERR(args);
2280 
2281 	inode = file_inode(file);
2282 
2283 	/*
2284 	 * Unprivileged query to obtain the containing subvolume root id. The
2285 	 * path is reset so it's consistent with btrfs_search_path_in_tree.
2286 	 */
2287 	if (args->treeid == 0)
2288 		args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2289 
2290 	if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2291 		args->name[0] = 0;
2292 		goto out;
2293 	}
2294 
2295 	if (!capable(CAP_SYS_ADMIN)) {
2296 		ret = -EPERM;
2297 		goto out;
2298 	}
2299 
2300 	ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2301 					args->treeid, args->objectid,
2302 					args->name);
2303 
2304 out:
2305 	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2306 		ret = -EFAULT;
2307 
2308 	kfree(args);
2309 	return ret;
2310 }
2311 
2312 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2313 					     void __user *arg)
2314 {
2315 	struct dentry *parent = file->f_path.dentry;
2316 	struct dentry *dentry;
2317 	struct inode *dir = d_inode(parent);
2318 	struct inode *inode;
2319 	struct btrfs_root *root = BTRFS_I(dir)->root;
2320 	struct btrfs_root *dest = NULL;
2321 	struct btrfs_ioctl_vol_args *vol_args;
2322 	struct btrfs_trans_handle *trans;
2323 	struct btrfs_block_rsv block_rsv;
2324 	u64 root_flags;
2325 	u64 qgroup_reserved;
2326 	int namelen;
2327 	int ret;
2328 	int err = 0;
2329 
2330 	vol_args = memdup_user(arg, sizeof(*vol_args));
2331 	if (IS_ERR(vol_args))
2332 		return PTR_ERR(vol_args);
2333 
2334 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2335 	namelen = strlen(vol_args->name);
2336 	if (strchr(vol_args->name, '/') ||
2337 	    strncmp(vol_args->name, "..", namelen) == 0) {
2338 		err = -EINVAL;
2339 		goto out;
2340 	}
2341 
2342 	err = mnt_want_write_file(file);
2343 	if (err)
2344 		goto out;
2345 
2346 
2347 	err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT);
2348 	if (err == -EINTR)
2349 		goto out_drop_write;
2350 	dentry = lookup_one_len(vol_args->name, parent, namelen);
2351 	if (IS_ERR(dentry)) {
2352 		err = PTR_ERR(dentry);
2353 		goto out_unlock_dir;
2354 	}
2355 
2356 	if (d_really_is_negative(dentry)) {
2357 		err = -ENOENT;
2358 		goto out_dput;
2359 	}
2360 
2361 	inode = d_inode(dentry);
2362 	dest = BTRFS_I(inode)->root;
2363 	if (!capable(CAP_SYS_ADMIN)) {
2364 		/*
2365 		 * Regular user.  Only allow this with a special mount
2366 		 * option, when the user has write+exec access to the
2367 		 * subvol root, and when rmdir(2) would have been
2368 		 * allowed.
2369 		 *
2370 		 * Note that this is _not_ check that the subvol is
2371 		 * empty or doesn't contain data that we wouldn't
2372 		 * otherwise be able to delete.
2373 		 *
2374 		 * Users who want to delete empty subvols should try
2375 		 * rmdir(2).
2376 		 */
2377 		err = -EPERM;
2378 		if (!btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
2379 			goto out_dput;
2380 
2381 		/*
2382 		 * Do not allow deletion if the parent dir is the same
2383 		 * as the dir to be deleted.  That means the ioctl
2384 		 * must be called on the dentry referencing the root
2385 		 * of the subvol, not a random directory contained
2386 		 * within it.
2387 		 */
2388 		err = -EINVAL;
2389 		if (root == dest)
2390 			goto out_dput;
2391 
2392 		err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2393 		if (err)
2394 			goto out_dput;
2395 	}
2396 
2397 	/* check if subvolume may be deleted by a user */
2398 	err = btrfs_may_delete(dir, dentry, 1);
2399 	if (err)
2400 		goto out_dput;
2401 
2402 	if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
2403 		err = -EINVAL;
2404 		goto out_dput;
2405 	}
2406 
2407 	mutex_lock(&inode->i_mutex);
2408 
2409 	/*
2410 	 * Don't allow to delete a subvolume with send in progress. This is
2411 	 * inside the i_mutex so the error handling that has to drop the bit
2412 	 * again is not run concurrently.
2413 	 */
2414 	spin_lock(&dest->root_item_lock);
2415 	root_flags = btrfs_root_flags(&dest->root_item);
2416 	if (dest->send_in_progress == 0) {
2417 		btrfs_set_root_flags(&dest->root_item,
2418 				root_flags | BTRFS_ROOT_SUBVOL_DEAD);
2419 		spin_unlock(&dest->root_item_lock);
2420 	} else {
2421 		spin_unlock(&dest->root_item_lock);
2422 		btrfs_warn(root->fs_info,
2423 			"Attempt to delete subvolume %llu during send",
2424 			dest->root_key.objectid);
2425 		err = -EPERM;
2426 		goto out_unlock_inode;
2427 	}
2428 
2429 	down_write(&root->fs_info->subvol_sem);
2430 
2431 	err = may_destroy_subvol(dest);
2432 	if (err)
2433 		goto out_up_write;
2434 
2435 	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
2436 	/*
2437 	 * One for dir inode, two for dir entries, two for root
2438 	 * ref/backref.
2439 	 */
2440 	err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
2441 					       5, &qgroup_reserved, true);
2442 	if (err)
2443 		goto out_up_write;
2444 
2445 	trans = btrfs_start_transaction(root, 0);
2446 	if (IS_ERR(trans)) {
2447 		err = PTR_ERR(trans);
2448 		goto out_release;
2449 	}
2450 	trans->block_rsv = &block_rsv;
2451 	trans->bytes_reserved = block_rsv.size;
2452 
2453 	ret = btrfs_unlink_subvol(trans, root, dir,
2454 				dest->root_key.objectid,
2455 				dentry->d_name.name,
2456 				dentry->d_name.len);
2457 	if (ret) {
2458 		err = ret;
2459 		btrfs_abort_transaction(trans, root, ret);
2460 		goto out_end_trans;
2461 	}
2462 
2463 	btrfs_record_root_in_trans(trans, dest);
2464 
2465 	memset(&dest->root_item.drop_progress, 0,
2466 		sizeof(dest->root_item.drop_progress));
2467 	dest->root_item.drop_level = 0;
2468 	btrfs_set_root_refs(&dest->root_item, 0);
2469 
2470 	if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
2471 		ret = btrfs_insert_orphan_item(trans,
2472 					root->fs_info->tree_root,
2473 					dest->root_key.objectid);
2474 		if (ret) {
2475 			btrfs_abort_transaction(trans, root, ret);
2476 			err = ret;
2477 			goto out_end_trans;
2478 		}
2479 	}
2480 
2481 	ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
2482 				  dest->root_item.uuid, BTRFS_UUID_KEY_SUBVOL,
2483 				  dest->root_key.objectid);
2484 	if (ret && ret != -ENOENT) {
2485 		btrfs_abort_transaction(trans, root, ret);
2486 		err = ret;
2487 		goto out_end_trans;
2488 	}
2489 	if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
2490 		ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
2491 					  dest->root_item.received_uuid,
2492 					  BTRFS_UUID_KEY_RECEIVED_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 	}
2500 
2501 out_end_trans:
2502 	trans->block_rsv = NULL;
2503 	trans->bytes_reserved = 0;
2504 	ret = btrfs_end_transaction(trans, root);
2505 	if (ret && !err)
2506 		err = ret;
2507 	inode->i_flags |= S_DEAD;
2508 out_release:
2509 	btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
2510 out_up_write:
2511 	up_write(&root->fs_info->subvol_sem);
2512 	if (err) {
2513 		spin_lock(&dest->root_item_lock);
2514 		root_flags = btrfs_root_flags(&dest->root_item);
2515 		btrfs_set_root_flags(&dest->root_item,
2516 				root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
2517 		spin_unlock(&dest->root_item_lock);
2518 	}
2519 out_unlock_inode:
2520 	mutex_unlock(&inode->i_mutex);
2521 	if (!err) {
2522 		d_invalidate(dentry);
2523 		btrfs_invalidate_inodes(dest);
2524 		d_delete(dentry);
2525 		ASSERT(dest->send_in_progress == 0);
2526 
2527 		/* the last ref */
2528 		if (dest->ino_cache_inode) {
2529 			iput(dest->ino_cache_inode);
2530 			dest->ino_cache_inode = NULL;
2531 		}
2532 	}
2533 out_dput:
2534 	dput(dentry);
2535 out_unlock_dir:
2536 	mutex_unlock(&dir->i_mutex);
2537 out_drop_write:
2538 	mnt_drop_write_file(file);
2539 out:
2540 	kfree(vol_args);
2541 	return err;
2542 }
2543 
2544 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2545 {
2546 	struct inode *inode = file_inode(file);
2547 	struct btrfs_root *root = BTRFS_I(inode)->root;
2548 	struct btrfs_ioctl_defrag_range_args *range;
2549 	int ret;
2550 
2551 	ret = mnt_want_write_file(file);
2552 	if (ret)
2553 		return ret;
2554 
2555 	if (btrfs_root_readonly(root)) {
2556 		ret = -EROFS;
2557 		goto out;
2558 	}
2559 
2560 	switch (inode->i_mode & S_IFMT) {
2561 	case S_IFDIR:
2562 		if (!capable(CAP_SYS_ADMIN)) {
2563 			ret = -EPERM;
2564 			goto out;
2565 		}
2566 		ret = btrfs_defrag_root(root);
2567 		if (ret)
2568 			goto out;
2569 		ret = btrfs_defrag_root(root->fs_info->extent_root);
2570 		break;
2571 	case S_IFREG:
2572 		if (!(file->f_mode & FMODE_WRITE)) {
2573 			ret = -EINVAL;
2574 			goto out;
2575 		}
2576 
2577 		range = kzalloc(sizeof(*range), GFP_KERNEL);
2578 		if (!range) {
2579 			ret = -ENOMEM;
2580 			goto out;
2581 		}
2582 
2583 		if (argp) {
2584 			if (copy_from_user(range, argp,
2585 					   sizeof(*range))) {
2586 				ret = -EFAULT;
2587 				kfree(range);
2588 				goto out;
2589 			}
2590 			/* compression requires us to start the IO */
2591 			if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2592 				range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
2593 				range->extent_thresh = (u32)-1;
2594 			}
2595 		} else {
2596 			/* the rest are all set to zero by kzalloc */
2597 			range->len = (u64)-1;
2598 		}
2599 		ret = btrfs_defrag_file(file_inode(file), file,
2600 					range, 0, 0);
2601 		if (ret > 0)
2602 			ret = 0;
2603 		kfree(range);
2604 		break;
2605 	default:
2606 		ret = -EINVAL;
2607 	}
2608 out:
2609 	mnt_drop_write_file(file);
2610 	return ret;
2611 }
2612 
2613 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
2614 {
2615 	struct btrfs_ioctl_vol_args *vol_args;
2616 	int ret;
2617 
2618 	if (!capable(CAP_SYS_ADMIN))
2619 		return -EPERM;
2620 
2621 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
2622 			1)) {
2623 		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2624 	}
2625 
2626 	mutex_lock(&root->fs_info->volume_mutex);
2627 	vol_args = memdup_user(arg, sizeof(*vol_args));
2628 	if (IS_ERR(vol_args)) {
2629 		ret = PTR_ERR(vol_args);
2630 		goto out;
2631 	}
2632 
2633 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2634 	ret = btrfs_init_new_device(root, vol_args->name);
2635 
2636 	if (!ret)
2637 		btrfs_info(root->fs_info, "disk added %s",vol_args->name);
2638 
2639 	kfree(vol_args);
2640 out:
2641 	mutex_unlock(&root->fs_info->volume_mutex);
2642 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
2643 	return ret;
2644 }
2645 
2646 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
2647 {
2648 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
2649 	struct btrfs_ioctl_vol_args *vol_args;
2650 	int ret;
2651 
2652 	if (!capable(CAP_SYS_ADMIN))
2653 		return -EPERM;
2654 
2655 	ret = mnt_want_write_file(file);
2656 	if (ret)
2657 		return ret;
2658 
2659 	vol_args = memdup_user(arg, sizeof(*vol_args));
2660 	if (IS_ERR(vol_args)) {
2661 		ret = PTR_ERR(vol_args);
2662 		goto err_drop;
2663 	}
2664 
2665 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2666 
2667 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
2668 			1)) {
2669 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2670 		goto out;
2671 	}
2672 
2673 	mutex_lock(&root->fs_info->volume_mutex);
2674 	ret = btrfs_rm_device(root, vol_args->name);
2675 	mutex_unlock(&root->fs_info->volume_mutex);
2676 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
2677 
2678 	if (!ret)
2679 		btrfs_info(root->fs_info, "disk deleted %s",vol_args->name);
2680 
2681 out:
2682 	kfree(vol_args);
2683 err_drop:
2684 	mnt_drop_write_file(file);
2685 	return ret;
2686 }
2687 
2688 static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
2689 {
2690 	struct btrfs_ioctl_fs_info_args *fi_args;
2691 	struct btrfs_device *device;
2692 	struct btrfs_device *next;
2693 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2694 	int ret = 0;
2695 
2696 	fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
2697 	if (!fi_args)
2698 		return -ENOMEM;
2699 
2700 	mutex_lock(&fs_devices->device_list_mutex);
2701 	fi_args->num_devices = fs_devices->num_devices;
2702 	memcpy(&fi_args->fsid, root->fs_info->fsid, sizeof(fi_args->fsid));
2703 
2704 	list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
2705 		if (device->devid > fi_args->max_id)
2706 			fi_args->max_id = device->devid;
2707 	}
2708 	mutex_unlock(&fs_devices->device_list_mutex);
2709 
2710 	fi_args->nodesize = root->fs_info->super_copy->nodesize;
2711 	fi_args->sectorsize = root->fs_info->super_copy->sectorsize;
2712 	fi_args->clone_alignment = root->fs_info->super_copy->sectorsize;
2713 
2714 	if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
2715 		ret = -EFAULT;
2716 
2717 	kfree(fi_args);
2718 	return ret;
2719 }
2720 
2721 static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg)
2722 {
2723 	struct btrfs_ioctl_dev_info_args *di_args;
2724 	struct btrfs_device *dev;
2725 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2726 	int ret = 0;
2727 	char *s_uuid = NULL;
2728 
2729 	di_args = memdup_user(arg, sizeof(*di_args));
2730 	if (IS_ERR(di_args))
2731 		return PTR_ERR(di_args);
2732 
2733 	if (!btrfs_is_empty_uuid(di_args->uuid))
2734 		s_uuid = di_args->uuid;
2735 
2736 	mutex_lock(&fs_devices->device_list_mutex);
2737 	dev = btrfs_find_device(root->fs_info, di_args->devid, s_uuid, NULL);
2738 
2739 	if (!dev) {
2740 		ret = -ENODEV;
2741 		goto out;
2742 	}
2743 
2744 	di_args->devid = dev->devid;
2745 	di_args->bytes_used = btrfs_device_get_bytes_used(dev);
2746 	di_args->total_bytes = btrfs_device_get_total_bytes(dev);
2747 	memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2748 	if (dev->name) {
2749 		struct rcu_string *name;
2750 
2751 		rcu_read_lock();
2752 		name = rcu_dereference(dev->name);
2753 		strncpy(di_args->path, name->str, sizeof(di_args->path));
2754 		rcu_read_unlock();
2755 		di_args->path[sizeof(di_args->path) - 1] = 0;
2756 	} else {
2757 		di_args->path[0] = '\0';
2758 	}
2759 
2760 out:
2761 	mutex_unlock(&fs_devices->device_list_mutex);
2762 	if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2763 		ret = -EFAULT;
2764 
2765 	kfree(di_args);
2766 	return ret;
2767 }
2768 
2769 static struct page *extent_same_get_page(struct inode *inode, pgoff_t index)
2770 {
2771 	struct page *page;
2772 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2773 
2774 	page = grab_cache_page(inode->i_mapping, index);
2775 	if (!page)
2776 		return NULL;
2777 
2778 	if (!PageUptodate(page)) {
2779 		if (extent_read_full_page_nolock(tree, page, btrfs_get_extent,
2780 						 0))
2781 			return NULL;
2782 		lock_page(page);
2783 		if (!PageUptodate(page)) {
2784 			unlock_page(page);
2785 			page_cache_release(page);
2786 			return NULL;
2787 		}
2788 	}
2789 	unlock_page(page);
2790 
2791 	return page;
2792 }
2793 
2794 static int gather_extent_pages(struct inode *inode, struct page **pages,
2795 			       int num_pages, u64 off)
2796 {
2797 	int i;
2798 	pgoff_t index = off >> PAGE_CACHE_SHIFT;
2799 
2800 	for (i = 0; i < num_pages; i++) {
2801 		pages[i] = extent_same_get_page(inode, index + i);
2802 		if (!pages[i])
2803 			return -ENOMEM;
2804 	}
2805 	return 0;
2806 }
2807 
2808 static inline void lock_extent_range(struct inode *inode, u64 off, u64 len)
2809 {
2810 	/* do any pending delalloc/csum calc on src, one way or
2811 	   another, and lock file content */
2812 	while (1) {
2813 		struct btrfs_ordered_extent *ordered;
2814 		lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2815 		ordered = btrfs_lookup_first_ordered_extent(inode,
2816 							    off + len - 1);
2817 		if ((!ordered ||
2818 		     ordered->file_offset + ordered->len <= off ||
2819 		     ordered->file_offset >= off + len) &&
2820 		    !test_range_bit(&BTRFS_I(inode)->io_tree, off,
2821 				    off + len - 1, EXTENT_DELALLOC, 0, NULL)) {
2822 			if (ordered)
2823 				btrfs_put_ordered_extent(ordered);
2824 			break;
2825 		}
2826 		unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2827 		if (ordered)
2828 			btrfs_put_ordered_extent(ordered);
2829 		btrfs_wait_ordered_range(inode, off, len);
2830 	}
2831 }
2832 
2833 static void btrfs_double_inode_unlock(struct inode *inode1, struct inode *inode2)
2834 {
2835 	mutex_unlock(&inode1->i_mutex);
2836 	mutex_unlock(&inode2->i_mutex);
2837 }
2838 
2839 static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
2840 {
2841 	if (inode1 < inode2)
2842 		swap(inode1, inode2);
2843 
2844 	mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
2845 	if (inode1 != inode2)
2846 		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
2847 }
2848 
2849 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
2850 				      struct inode *inode2, u64 loff2, u64 len)
2851 {
2852 	unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
2853 	unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
2854 }
2855 
2856 static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
2857 				     struct inode *inode2, u64 loff2, u64 len)
2858 {
2859 	if (inode1 < inode2) {
2860 		swap(inode1, inode2);
2861 		swap(loff1, loff2);
2862 	}
2863 	lock_extent_range(inode1, loff1, len);
2864 	if (inode1 != inode2)
2865 		lock_extent_range(inode2, loff2, len);
2866 }
2867 
2868 struct cmp_pages {
2869 	int		num_pages;
2870 	struct page	**src_pages;
2871 	struct page	**dst_pages;
2872 };
2873 
2874 static void btrfs_cmp_data_free(struct cmp_pages *cmp)
2875 {
2876 	int i;
2877 	struct page *pg;
2878 
2879 	for (i = 0; i < cmp->num_pages; i++) {
2880 		pg = cmp->src_pages[i];
2881 		if (pg)
2882 			page_cache_release(pg);
2883 		pg = cmp->dst_pages[i];
2884 		if (pg)
2885 			page_cache_release(pg);
2886 	}
2887 	kfree(cmp->src_pages);
2888 	kfree(cmp->dst_pages);
2889 }
2890 
2891 static int btrfs_cmp_data_prepare(struct inode *src, u64 loff,
2892 				  struct inode *dst, u64 dst_loff,
2893 				  u64 len, struct cmp_pages *cmp)
2894 {
2895 	int ret;
2896 	int num_pages = PAGE_CACHE_ALIGN(len) >> PAGE_CACHE_SHIFT;
2897 	struct page **src_pgarr, **dst_pgarr;
2898 
2899 	/*
2900 	 * We must gather up all the pages before we initiate our
2901 	 * extent locking. We use an array for the page pointers. Size
2902 	 * of the array is bounded by len, which is in turn bounded by
2903 	 * BTRFS_MAX_DEDUPE_LEN.
2904 	 */
2905 	src_pgarr = kzalloc(num_pages * sizeof(struct page *), GFP_NOFS);
2906 	dst_pgarr = kzalloc(num_pages * sizeof(struct page *), GFP_NOFS);
2907 	if (!src_pgarr || !dst_pgarr) {
2908 		kfree(src_pgarr);
2909 		kfree(dst_pgarr);
2910 		return -ENOMEM;
2911 	}
2912 	cmp->num_pages = num_pages;
2913 	cmp->src_pages = src_pgarr;
2914 	cmp->dst_pages = dst_pgarr;
2915 
2916 	ret = gather_extent_pages(src, cmp->src_pages, cmp->num_pages, loff);
2917 	if (ret)
2918 		goto out;
2919 
2920 	ret = gather_extent_pages(dst, cmp->dst_pages, cmp->num_pages, dst_loff);
2921 
2922 out:
2923 	if (ret)
2924 		btrfs_cmp_data_free(cmp);
2925 	return 0;
2926 }
2927 
2928 static int btrfs_cmp_data(struct inode *src, u64 loff, struct inode *dst,
2929 			  u64 dst_loff, u64 len, struct cmp_pages *cmp)
2930 {
2931 	int ret = 0;
2932 	int i;
2933 	struct page *src_page, *dst_page;
2934 	unsigned int cmp_len = PAGE_CACHE_SIZE;
2935 	void *addr, *dst_addr;
2936 
2937 	i = 0;
2938 	while (len) {
2939 		if (len < PAGE_CACHE_SIZE)
2940 			cmp_len = len;
2941 
2942 		BUG_ON(i >= cmp->num_pages);
2943 
2944 		src_page = cmp->src_pages[i];
2945 		dst_page = cmp->dst_pages[i];
2946 
2947 		addr = kmap_atomic(src_page);
2948 		dst_addr = kmap_atomic(dst_page);
2949 
2950 		flush_dcache_page(src_page);
2951 		flush_dcache_page(dst_page);
2952 
2953 		if (memcmp(addr, dst_addr, cmp_len))
2954 			ret = BTRFS_SAME_DATA_DIFFERS;
2955 
2956 		kunmap_atomic(addr);
2957 		kunmap_atomic(dst_addr);
2958 
2959 		if (ret)
2960 			break;
2961 
2962 		len -= cmp_len;
2963 		i++;
2964 	}
2965 
2966 	return ret;
2967 }
2968 
2969 static int extent_same_check_offsets(struct inode *inode, u64 off, u64 *plen,
2970 				     u64 olen)
2971 {
2972 	u64 len = *plen;
2973 	u64 bs = BTRFS_I(inode)->root->fs_info->sb->s_blocksize;
2974 
2975 	if (off + olen > inode->i_size || off + olen < off)
2976 		return -EINVAL;
2977 
2978 	/* if we extend to eof, continue to block boundary */
2979 	if (off + len == inode->i_size)
2980 		*plen = len = ALIGN(inode->i_size, bs) - off;
2981 
2982 	/* Check that we are block aligned - btrfs_clone() requires this */
2983 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs))
2984 		return -EINVAL;
2985 
2986 	return 0;
2987 }
2988 
2989 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
2990 			     struct inode *dst, u64 dst_loff)
2991 {
2992 	int ret;
2993 	u64 len = olen;
2994 	struct cmp_pages cmp;
2995 	int same_inode = 0;
2996 	u64 same_lock_start = 0;
2997 	u64 same_lock_len = 0;
2998 
2999 	if (src == dst)
3000 		same_inode = 1;
3001 
3002 	if (len == 0)
3003 		return 0;
3004 
3005 	if (same_inode) {
3006 		mutex_lock(&src->i_mutex);
3007 
3008 		ret = extent_same_check_offsets(src, loff, &len, olen);
3009 		if (ret)
3010 			goto out_unlock;
3011 
3012 		/*
3013 		 * Single inode case wants the same checks, except we
3014 		 * don't want our length pushed out past i_size as
3015 		 * comparing that data range makes no sense.
3016 		 *
3017 		 * extent_same_check_offsets() will do this for an
3018 		 * unaligned length at i_size, so catch it here and
3019 		 * reject the request.
3020 		 *
3021 		 * This effectively means we require aligned extents
3022 		 * for the single-inode case, whereas the other cases
3023 		 * allow an unaligned length so long as it ends at
3024 		 * i_size.
3025 		 */
3026 		if (len != olen) {
3027 			ret = -EINVAL;
3028 			goto out_unlock;
3029 		}
3030 
3031 		/* Check for overlapping ranges */
3032 		if (dst_loff + len > loff && dst_loff < loff + len) {
3033 			ret = -EINVAL;
3034 			goto out_unlock;
3035 		}
3036 
3037 		same_lock_start = min_t(u64, loff, dst_loff);
3038 		same_lock_len = max_t(u64, loff, dst_loff) + len - same_lock_start;
3039 	} else {
3040 		btrfs_double_inode_lock(src, dst);
3041 
3042 		ret = extent_same_check_offsets(src, loff, &len, olen);
3043 		if (ret)
3044 			goto out_unlock;
3045 
3046 		ret = extent_same_check_offsets(dst, dst_loff, &len, olen);
3047 		if (ret)
3048 			goto out_unlock;
3049 	}
3050 
3051 	/* don't make the dst file partly checksummed */
3052 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3053 	    (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
3054 		ret = -EINVAL;
3055 		goto out_unlock;
3056 	}
3057 
3058 	ret = btrfs_cmp_data_prepare(src, loff, dst, dst_loff, olen, &cmp);
3059 	if (ret)
3060 		goto out_unlock;
3061 
3062 	if (same_inode)
3063 		lock_extent_range(src, same_lock_start, same_lock_len);
3064 	else
3065 		btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
3066 
3067 	/* pass original length for comparison so we stay within i_size */
3068 	ret = btrfs_cmp_data(src, loff, dst, dst_loff, olen, &cmp);
3069 	if (ret == 0)
3070 		ret = btrfs_clone(src, dst, loff, olen, len, dst_loff, 1);
3071 
3072 	if (same_inode)
3073 		unlock_extent(&BTRFS_I(src)->io_tree, same_lock_start,
3074 			      same_lock_start + same_lock_len - 1);
3075 	else
3076 		btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
3077 
3078 	btrfs_cmp_data_free(&cmp);
3079 out_unlock:
3080 	if (same_inode)
3081 		mutex_unlock(&src->i_mutex);
3082 	else
3083 		btrfs_double_inode_unlock(src, dst);
3084 
3085 	return ret;
3086 }
3087 
3088 #define BTRFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
3089 
3090 static long btrfs_ioctl_file_extent_same(struct file *file,
3091 			struct btrfs_ioctl_same_args __user *argp)
3092 {
3093 	struct btrfs_ioctl_same_args *same = NULL;
3094 	struct btrfs_ioctl_same_extent_info *info;
3095 	struct inode *src = file_inode(file);
3096 	u64 off;
3097 	u64 len;
3098 	int i;
3099 	int ret;
3100 	unsigned long size;
3101 	u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
3102 	bool is_admin = capable(CAP_SYS_ADMIN);
3103 	u16 count;
3104 
3105 	if (!(file->f_mode & FMODE_READ))
3106 		return -EINVAL;
3107 
3108 	ret = mnt_want_write_file(file);
3109 	if (ret)
3110 		return ret;
3111 
3112 	if (get_user(count, &argp->dest_count)) {
3113 		ret = -EFAULT;
3114 		goto out;
3115 	}
3116 
3117 	size = offsetof(struct btrfs_ioctl_same_args __user, info[count]);
3118 
3119 	same = memdup_user(argp, size);
3120 
3121 	if (IS_ERR(same)) {
3122 		ret = PTR_ERR(same);
3123 		same = NULL;
3124 		goto out;
3125 	}
3126 
3127 	off = same->logical_offset;
3128 	len = same->length;
3129 
3130 	/*
3131 	 * Limit the total length we will dedupe for each operation.
3132 	 * This is intended to bound the total time spent in this
3133 	 * ioctl to something sane.
3134 	 */
3135 	if (len > BTRFS_MAX_DEDUPE_LEN)
3136 		len = BTRFS_MAX_DEDUPE_LEN;
3137 
3138 	if (WARN_ON_ONCE(bs < PAGE_CACHE_SIZE)) {
3139 		/*
3140 		 * Btrfs does not support blocksize < page_size. As a
3141 		 * result, btrfs_cmp_data() won't correctly handle
3142 		 * this situation without an update.
3143 		 */
3144 		ret = -EINVAL;
3145 		goto out;
3146 	}
3147 
3148 	ret = -EISDIR;
3149 	if (S_ISDIR(src->i_mode))
3150 		goto out;
3151 
3152 	ret = -EACCES;
3153 	if (!S_ISREG(src->i_mode))
3154 		goto out;
3155 
3156 	/* pre-format output fields to sane values */
3157 	for (i = 0; i < count; i++) {
3158 		same->info[i].bytes_deduped = 0ULL;
3159 		same->info[i].status = 0;
3160 	}
3161 
3162 	for (i = 0, info = same->info; i < count; i++, info++) {
3163 		struct inode *dst;
3164 		struct fd dst_file = fdget(info->fd);
3165 		if (!dst_file.file) {
3166 			info->status = -EBADF;
3167 			continue;
3168 		}
3169 		dst = file_inode(dst_file.file);
3170 
3171 		if (!(is_admin || (dst_file.file->f_mode & FMODE_WRITE))) {
3172 			info->status = -EINVAL;
3173 		} else if (file->f_path.mnt != dst_file.file->f_path.mnt) {
3174 			info->status = -EXDEV;
3175 		} else if (S_ISDIR(dst->i_mode)) {
3176 			info->status = -EISDIR;
3177 		} else if (!S_ISREG(dst->i_mode)) {
3178 			info->status = -EACCES;
3179 		} else {
3180 			info->status = btrfs_extent_same(src, off, len, dst,
3181 							info->logical_offset);
3182 			if (info->status == 0)
3183 				info->bytes_deduped += len;
3184 		}
3185 		fdput(dst_file);
3186 	}
3187 
3188 	ret = copy_to_user(argp, same, size);
3189 	if (ret)
3190 		ret = -EFAULT;
3191 
3192 out:
3193 	mnt_drop_write_file(file);
3194 	kfree(same);
3195 	return ret;
3196 }
3197 
3198 /* Helper to check and see if this root currently has a ref on the given disk
3199  * bytenr.  If it does then we need to update the quota for this root.  This
3200  * doesn't do anything if quotas aren't enabled.
3201  */
3202 static int check_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3203 		     u64 disko)
3204 {
3205 	struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
3206 	struct ulist *roots;
3207 	struct ulist_iterator uiter;
3208 	struct ulist_node *root_node = NULL;
3209 	int ret;
3210 
3211 	if (!root->fs_info->quota_enabled)
3212 		return 1;
3213 
3214 	btrfs_get_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
3215 	ret = btrfs_find_all_roots(trans, root->fs_info, disko,
3216 				   tree_mod_seq_elem.seq, &roots);
3217 	if (ret < 0)
3218 		goto out;
3219 	ret = 0;
3220 	ULIST_ITER_INIT(&uiter);
3221 	while ((root_node = ulist_next(roots, &uiter))) {
3222 		if (root_node->val == root->objectid) {
3223 			ret = 1;
3224 			break;
3225 		}
3226 	}
3227 	ulist_free(roots);
3228 out:
3229 	btrfs_put_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
3230 	return ret;
3231 }
3232 
3233 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
3234 				     struct inode *inode,
3235 				     u64 endoff,
3236 				     const u64 destoff,
3237 				     const u64 olen,
3238 				     int no_time_update)
3239 {
3240 	struct btrfs_root *root = BTRFS_I(inode)->root;
3241 	int ret;
3242 
3243 	inode_inc_iversion(inode);
3244 	if (!no_time_update)
3245 		inode->i_mtime = inode->i_ctime = CURRENT_TIME;
3246 	/*
3247 	 * We round up to the block size at eof when determining which
3248 	 * extents to clone above, but shouldn't round up the file size.
3249 	 */
3250 	if (endoff > destoff + olen)
3251 		endoff = destoff + olen;
3252 	if (endoff > inode->i_size)
3253 		btrfs_i_size_write(inode, endoff);
3254 
3255 	ret = btrfs_update_inode(trans, root, inode);
3256 	if (ret) {
3257 		btrfs_abort_transaction(trans, root, ret);
3258 		btrfs_end_transaction(trans, root);
3259 		goto out;
3260 	}
3261 	ret = btrfs_end_transaction(trans, root);
3262 out:
3263 	return ret;
3264 }
3265 
3266 static void clone_update_extent_map(struct inode *inode,
3267 				    const struct btrfs_trans_handle *trans,
3268 				    const struct btrfs_path *path,
3269 				    const u64 hole_offset,
3270 				    const u64 hole_len)
3271 {
3272 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3273 	struct extent_map *em;
3274 	int ret;
3275 
3276 	em = alloc_extent_map();
3277 	if (!em) {
3278 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3279 			&BTRFS_I(inode)->runtime_flags);
3280 		return;
3281 	}
3282 
3283 	if (path) {
3284 		struct btrfs_file_extent_item *fi;
3285 
3286 		fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
3287 				    struct btrfs_file_extent_item);
3288 		btrfs_extent_item_to_extent_map(inode, path, fi, false, em);
3289 		em->generation = -1;
3290 		if (btrfs_file_extent_type(path->nodes[0], fi) ==
3291 		    BTRFS_FILE_EXTENT_INLINE)
3292 			set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3293 				&BTRFS_I(inode)->runtime_flags);
3294 	} else {
3295 		em->start = hole_offset;
3296 		em->len = hole_len;
3297 		em->ram_bytes = em->len;
3298 		em->orig_start = hole_offset;
3299 		em->block_start = EXTENT_MAP_HOLE;
3300 		em->block_len = 0;
3301 		em->orig_block_len = 0;
3302 		em->compress_type = BTRFS_COMPRESS_NONE;
3303 		em->generation = trans->transid;
3304 	}
3305 
3306 	while (1) {
3307 		write_lock(&em_tree->lock);
3308 		ret = add_extent_mapping(em_tree, em, 1);
3309 		write_unlock(&em_tree->lock);
3310 		if (ret != -EEXIST) {
3311 			free_extent_map(em);
3312 			break;
3313 		}
3314 		btrfs_drop_extent_cache(inode, em->start,
3315 					em->start + em->len - 1, 0);
3316 	}
3317 
3318 	if (ret)
3319 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3320 			&BTRFS_I(inode)->runtime_flags);
3321 }
3322 
3323 /**
3324  * btrfs_clone() - clone a range from inode file to another
3325  *
3326  * @src: Inode to clone from
3327  * @inode: Inode to clone to
3328  * @off: Offset within source to start clone from
3329  * @olen: Original length, passed by user, of range to clone
3330  * @olen_aligned: Block-aligned value of olen
3331  * @destoff: Offset within @inode to start clone
3332  * @no_time_update: Whether to update mtime/ctime on the target inode
3333  */
3334 static int btrfs_clone(struct inode *src, struct inode *inode,
3335 		       const u64 off, const u64 olen, const u64 olen_aligned,
3336 		       const u64 destoff, int no_time_update)
3337 {
3338 	struct btrfs_root *root = BTRFS_I(inode)->root;
3339 	struct btrfs_path *path = NULL;
3340 	struct extent_buffer *leaf;
3341 	struct btrfs_trans_handle *trans;
3342 	char *buf = NULL;
3343 	struct btrfs_key key;
3344 	u32 nritems;
3345 	int slot;
3346 	int ret;
3347 	int no_quota;
3348 	const u64 len = olen_aligned;
3349 	u64 last_disko = 0;
3350 	u64 last_dest_end = destoff;
3351 
3352 	ret = -ENOMEM;
3353 	buf = vmalloc(root->nodesize);
3354 	if (!buf)
3355 		return ret;
3356 
3357 	path = btrfs_alloc_path();
3358 	if (!path) {
3359 		vfree(buf);
3360 		return ret;
3361 	}
3362 
3363 	path->reada = 2;
3364 	/* clone data */
3365 	key.objectid = btrfs_ino(src);
3366 	key.type = BTRFS_EXTENT_DATA_KEY;
3367 	key.offset = off;
3368 
3369 	while (1) {
3370 		u64 next_key_min_offset = key.offset + 1;
3371 
3372 		/*
3373 		 * note the key will change type as we walk through the
3374 		 * tree.
3375 		 */
3376 		path->leave_spinning = 1;
3377 		ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
3378 				0, 0);
3379 		if (ret < 0)
3380 			goto out;
3381 		/*
3382 		 * First search, if no extent item that starts at offset off was
3383 		 * found but the previous item is an extent item, it's possible
3384 		 * it might overlap our target range, therefore process it.
3385 		 */
3386 		if (key.offset == off && ret > 0 && path->slots[0] > 0) {
3387 			btrfs_item_key_to_cpu(path->nodes[0], &key,
3388 					      path->slots[0] - 1);
3389 			if (key.type == BTRFS_EXTENT_DATA_KEY)
3390 				path->slots[0]--;
3391 		}
3392 
3393 		nritems = btrfs_header_nritems(path->nodes[0]);
3394 process_slot:
3395 		no_quota = 1;
3396 		if (path->slots[0] >= nritems) {
3397 			ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
3398 			if (ret < 0)
3399 				goto out;
3400 			if (ret > 0)
3401 				break;
3402 			nritems = btrfs_header_nritems(path->nodes[0]);
3403 		}
3404 		leaf = path->nodes[0];
3405 		slot = path->slots[0];
3406 
3407 		btrfs_item_key_to_cpu(leaf, &key, slot);
3408 		if (key.type > BTRFS_EXTENT_DATA_KEY ||
3409 		    key.objectid != btrfs_ino(src))
3410 			break;
3411 
3412 		if (key.type == BTRFS_EXTENT_DATA_KEY) {
3413 			struct btrfs_file_extent_item *extent;
3414 			int type;
3415 			u32 size;
3416 			struct btrfs_key new_key;
3417 			u64 disko = 0, diskl = 0;
3418 			u64 datao = 0, datal = 0;
3419 			u8 comp;
3420 			u64 drop_start;
3421 
3422 			extent = btrfs_item_ptr(leaf, slot,
3423 						struct btrfs_file_extent_item);
3424 			comp = btrfs_file_extent_compression(leaf, extent);
3425 			type = btrfs_file_extent_type(leaf, extent);
3426 			if (type == BTRFS_FILE_EXTENT_REG ||
3427 			    type == BTRFS_FILE_EXTENT_PREALLOC) {
3428 				disko = btrfs_file_extent_disk_bytenr(leaf,
3429 								      extent);
3430 				diskl = btrfs_file_extent_disk_num_bytes(leaf,
3431 								 extent);
3432 				datao = btrfs_file_extent_offset(leaf, extent);
3433 				datal = btrfs_file_extent_num_bytes(leaf,
3434 								    extent);
3435 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
3436 				/* take upper bound, may be compressed */
3437 				datal = btrfs_file_extent_ram_bytes(leaf,
3438 								    extent);
3439 			}
3440 
3441 			/*
3442 			 * The first search might have left us at an extent
3443 			 * item that ends before our target range's start, can
3444 			 * happen if we have holes and NO_HOLES feature enabled.
3445 			 */
3446 			if (key.offset + datal <= off) {
3447 				path->slots[0]++;
3448 				goto process_slot;
3449 			} else if (key.offset >= off + len) {
3450 				break;
3451 			}
3452 			next_key_min_offset = key.offset + datal;
3453 			size = btrfs_item_size_nr(leaf, slot);
3454 			read_extent_buffer(leaf, buf,
3455 					   btrfs_item_ptr_offset(leaf, slot),
3456 					   size);
3457 
3458 			btrfs_release_path(path);
3459 			path->leave_spinning = 0;
3460 
3461 			memcpy(&new_key, &key, sizeof(new_key));
3462 			new_key.objectid = btrfs_ino(inode);
3463 			if (off <= key.offset)
3464 				new_key.offset = key.offset + destoff - off;
3465 			else
3466 				new_key.offset = destoff;
3467 
3468 			/*
3469 			 * Deal with a hole that doesn't have an extent item
3470 			 * that represents it (NO_HOLES feature enabled).
3471 			 * This hole is either in the middle of the cloning
3472 			 * range or at the beginning (fully overlaps it or
3473 			 * partially overlaps it).
3474 			 */
3475 			if (new_key.offset != last_dest_end)
3476 				drop_start = last_dest_end;
3477 			else
3478 				drop_start = new_key.offset;
3479 
3480 			/*
3481 			 * 1 - adjusting old extent (we may have to split it)
3482 			 * 1 - add new extent
3483 			 * 1 - inode update
3484 			 */
3485 			trans = btrfs_start_transaction(root, 3);
3486 			if (IS_ERR(trans)) {
3487 				ret = PTR_ERR(trans);
3488 				goto out;
3489 			}
3490 
3491 			if (type == BTRFS_FILE_EXTENT_REG ||
3492 			    type == BTRFS_FILE_EXTENT_PREALLOC) {
3493 				/*
3494 				 *    a  | --- range to clone ---|  b
3495 				 * | ------------- extent ------------- |
3496 				 */
3497 
3498 				/* subtract range b */
3499 				if (key.offset + datal > off + len)
3500 					datal = off + len - key.offset;
3501 
3502 				/* subtract range a */
3503 				if (off > key.offset) {
3504 					datao += off - key.offset;
3505 					datal -= off - key.offset;
3506 				}
3507 
3508 				ret = btrfs_drop_extents(trans, root, inode,
3509 							 drop_start,
3510 							 new_key.offset + datal,
3511 							 1);
3512 				if (ret) {
3513 					if (ret != -EOPNOTSUPP)
3514 						btrfs_abort_transaction(trans,
3515 								root, ret);
3516 					btrfs_end_transaction(trans, root);
3517 					goto out;
3518 				}
3519 
3520 				ret = btrfs_insert_empty_item(trans, root, path,
3521 							      &new_key, size);
3522 				if (ret) {
3523 					btrfs_abort_transaction(trans, root,
3524 								ret);
3525 					btrfs_end_transaction(trans, root);
3526 					goto out;
3527 				}
3528 
3529 				leaf = path->nodes[0];
3530 				slot = path->slots[0];
3531 				write_extent_buffer(leaf, buf,
3532 					    btrfs_item_ptr_offset(leaf, slot),
3533 					    size);
3534 
3535 				extent = btrfs_item_ptr(leaf, slot,
3536 						struct btrfs_file_extent_item);
3537 
3538 				/* disko == 0 means it's a hole */
3539 				if (!disko)
3540 					datao = 0;
3541 
3542 				btrfs_set_file_extent_offset(leaf, extent,
3543 							     datao);
3544 				btrfs_set_file_extent_num_bytes(leaf, extent,
3545 								datal);
3546 
3547 				/*
3548 				 * We need to look up the roots that point at
3549 				 * this bytenr and see if the new root does.  If
3550 				 * it does not we need to make sure we update
3551 				 * quotas appropriately.
3552 				 */
3553 				if (disko && root != BTRFS_I(src)->root &&
3554 				    disko != last_disko) {
3555 					no_quota = check_ref(trans, root,
3556 							     disko);
3557 					if (no_quota < 0) {
3558 						btrfs_abort_transaction(trans,
3559 									root,
3560 									ret);
3561 						btrfs_end_transaction(trans,
3562 								      root);
3563 						ret = no_quota;
3564 						goto out;
3565 					}
3566 				}
3567 
3568 				if (disko) {
3569 					inode_add_bytes(inode, datal);
3570 					ret = btrfs_inc_extent_ref(trans, root,
3571 							disko, diskl, 0,
3572 							root->root_key.objectid,
3573 							btrfs_ino(inode),
3574 							new_key.offset - datao,
3575 							no_quota);
3576 					if (ret) {
3577 						btrfs_abort_transaction(trans,
3578 									root,
3579 									ret);
3580 						btrfs_end_transaction(trans,
3581 								      root);
3582 						goto out;
3583 
3584 					}
3585 				}
3586 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
3587 				u64 skip = 0;
3588 				u64 trim = 0;
3589 				u64 aligned_end = 0;
3590 
3591 				/*
3592 				 * Don't copy an inline extent into an offset
3593 				 * greater than zero. Having an inline extent
3594 				 * at such an offset results in chaos as btrfs
3595 				 * isn't prepared for such cases. Just skip
3596 				 * this case for the same reasons as commented
3597 				 * at btrfs_ioctl_clone().
3598 				 */
3599 				if (last_dest_end > 0) {
3600 					ret = -EOPNOTSUPP;
3601 					btrfs_end_transaction(trans, root);
3602 					goto out;
3603 				}
3604 
3605 				if (off > key.offset) {
3606 					skip = off - key.offset;
3607 					new_key.offset += skip;
3608 				}
3609 
3610 				if (key.offset + datal > off + len)
3611 					trim = key.offset + datal - (off + len);
3612 
3613 				if (comp && (skip || trim)) {
3614 					ret = -EINVAL;
3615 					btrfs_end_transaction(trans, root);
3616 					goto out;
3617 				}
3618 				size -= skip + trim;
3619 				datal -= skip + trim;
3620 
3621 				aligned_end = ALIGN(new_key.offset + datal,
3622 						    root->sectorsize);
3623 				ret = btrfs_drop_extents(trans, root, inode,
3624 							 drop_start,
3625 							 aligned_end,
3626 							 1);
3627 				if (ret) {
3628 					if (ret != -EOPNOTSUPP)
3629 						btrfs_abort_transaction(trans,
3630 							root, ret);
3631 					btrfs_end_transaction(trans, root);
3632 					goto out;
3633 				}
3634 
3635 				ret = btrfs_insert_empty_item(trans, root, path,
3636 							      &new_key, size);
3637 				if (ret) {
3638 					btrfs_abort_transaction(trans, root,
3639 								ret);
3640 					btrfs_end_transaction(trans, root);
3641 					goto out;
3642 				}
3643 
3644 				if (skip) {
3645 					u32 start =
3646 					  btrfs_file_extent_calc_inline_size(0);
3647 					memmove(buf+start, buf+start+skip,
3648 						datal);
3649 				}
3650 
3651 				leaf = path->nodes[0];
3652 				slot = path->slots[0];
3653 				write_extent_buffer(leaf, buf,
3654 					    btrfs_item_ptr_offset(leaf, slot),
3655 					    size);
3656 				inode_add_bytes(inode, datal);
3657 			}
3658 
3659 			/* If we have an implicit hole (NO_HOLES feature). */
3660 			if (drop_start < new_key.offset)
3661 				clone_update_extent_map(inode, trans,
3662 						NULL, drop_start,
3663 						new_key.offset - drop_start);
3664 
3665 			clone_update_extent_map(inode, trans, path, 0, 0);
3666 
3667 			btrfs_mark_buffer_dirty(leaf);
3668 			btrfs_release_path(path);
3669 
3670 			last_dest_end = ALIGN(new_key.offset + datal,
3671 					      root->sectorsize);
3672 			ret = clone_finish_inode_update(trans, inode,
3673 							last_dest_end,
3674 							destoff, olen,
3675 							no_time_update);
3676 			if (ret)
3677 				goto out;
3678 			if (new_key.offset + datal >= destoff + len)
3679 				break;
3680 		}
3681 		btrfs_release_path(path);
3682 		key.offset = next_key_min_offset;
3683 	}
3684 	ret = 0;
3685 
3686 	if (last_dest_end < destoff + len) {
3687 		/*
3688 		 * We have an implicit hole (NO_HOLES feature is enabled) that
3689 		 * fully or partially overlaps our cloning range at its end.
3690 		 */
3691 		btrfs_release_path(path);
3692 
3693 		/*
3694 		 * 1 - remove extent(s)
3695 		 * 1 - inode update
3696 		 */
3697 		trans = btrfs_start_transaction(root, 2);
3698 		if (IS_ERR(trans)) {
3699 			ret = PTR_ERR(trans);
3700 			goto out;
3701 		}
3702 		ret = btrfs_drop_extents(trans, root, inode,
3703 					 last_dest_end, destoff + len, 1);
3704 		if (ret) {
3705 			if (ret != -EOPNOTSUPP)
3706 				btrfs_abort_transaction(trans, root, ret);
3707 			btrfs_end_transaction(trans, root);
3708 			goto out;
3709 		}
3710 		clone_update_extent_map(inode, trans, NULL, last_dest_end,
3711 					destoff + len - last_dest_end);
3712 		ret = clone_finish_inode_update(trans, inode, destoff + len,
3713 						destoff, olen, no_time_update);
3714 	}
3715 
3716 out:
3717 	btrfs_free_path(path);
3718 	vfree(buf);
3719 	return ret;
3720 }
3721 
3722 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
3723 				       u64 off, u64 olen, u64 destoff)
3724 {
3725 	struct inode *inode = file_inode(file);
3726 	struct btrfs_root *root = BTRFS_I(inode)->root;
3727 	struct fd src_file;
3728 	struct inode *src;
3729 	int ret;
3730 	u64 len = olen;
3731 	u64 bs = root->fs_info->sb->s_blocksize;
3732 	int same_inode = 0;
3733 
3734 	/*
3735 	 * TODO:
3736 	 * - split compressed inline extents.  annoying: we need to
3737 	 *   decompress into destination's address_space (the file offset
3738 	 *   may change, so source mapping won't do), then recompress (or
3739 	 *   otherwise reinsert) a subrange.
3740 	 *
3741 	 * - split destination inode's inline extents.  The inline extents can
3742 	 *   be either compressed or non-compressed.
3743 	 */
3744 
3745 	/* the destination must be opened for writing */
3746 	if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
3747 		return -EINVAL;
3748 
3749 	if (btrfs_root_readonly(root))
3750 		return -EROFS;
3751 
3752 	ret = mnt_want_write_file(file);
3753 	if (ret)
3754 		return ret;
3755 
3756 	src_file = fdget(srcfd);
3757 	if (!src_file.file) {
3758 		ret = -EBADF;
3759 		goto out_drop_write;
3760 	}
3761 
3762 	ret = -EXDEV;
3763 	if (src_file.file->f_path.mnt != file->f_path.mnt)
3764 		goto out_fput;
3765 
3766 	src = file_inode(src_file.file);
3767 
3768 	ret = -EINVAL;
3769 	if (src == inode)
3770 		same_inode = 1;
3771 
3772 	/* the src must be open for reading */
3773 	if (!(src_file.file->f_mode & FMODE_READ))
3774 		goto out_fput;
3775 
3776 	/* don't make the dst file partly checksummed */
3777 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3778 	    (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
3779 		goto out_fput;
3780 
3781 	ret = -EISDIR;
3782 	if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
3783 		goto out_fput;
3784 
3785 	ret = -EXDEV;
3786 	if (src->i_sb != inode->i_sb)
3787 		goto out_fput;
3788 
3789 	if (!same_inode) {
3790 		if (inode < src) {
3791 			mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
3792 			mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
3793 		} else {
3794 			mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
3795 			mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
3796 		}
3797 	} else {
3798 		mutex_lock(&src->i_mutex);
3799 	}
3800 
3801 	/* determine range to clone */
3802 	ret = -EINVAL;
3803 	if (off + len > src->i_size || off + len < off)
3804 		goto out_unlock;
3805 	if (len == 0)
3806 		olen = len = src->i_size - off;
3807 	/* if we extend to eof, continue to block boundary */
3808 	if (off + len == src->i_size)
3809 		len = ALIGN(src->i_size, bs) - off;
3810 
3811 	if (len == 0) {
3812 		ret = 0;
3813 		goto out_unlock;
3814 	}
3815 
3816 	/* verify the end result is block aligned */
3817 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
3818 	    !IS_ALIGNED(destoff, bs))
3819 		goto out_unlock;
3820 
3821 	/* verify if ranges are overlapped within the same file */
3822 	if (same_inode) {
3823 		if (destoff + len > off && destoff < off + len)
3824 			goto out_unlock;
3825 	}
3826 
3827 	if (destoff > inode->i_size) {
3828 		ret = btrfs_cont_expand(inode, inode->i_size, destoff);
3829 		if (ret)
3830 			goto out_unlock;
3831 	}
3832 
3833 	/*
3834 	 * Lock the target range too. Right after we replace the file extent
3835 	 * items in the fs tree (which now point to the cloned data), we might
3836 	 * have a worker replace them with extent items relative to a write
3837 	 * operation that was issued before this clone operation (i.e. confront
3838 	 * with inode.c:btrfs_finish_ordered_io).
3839 	 */
3840 	if (same_inode) {
3841 		u64 lock_start = min_t(u64, off, destoff);
3842 		u64 lock_len = max_t(u64, off, destoff) + len - lock_start;
3843 
3844 		lock_extent_range(src, lock_start, lock_len);
3845 	} else {
3846 		lock_extent_range(src, off, len);
3847 		lock_extent_range(inode, destoff, len);
3848 	}
3849 
3850 	ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
3851 
3852 	if (same_inode) {
3853 		u64 lock_start = min_t(u64, off, destoff);
3854 		u64 lock_end = max_t(u64, off, destoff) + len - 1;
3855 
3856 		unlock_extent(&BTRFS_I(src)->io_tree, lock_start, lock_end);
3857 	} else {
3858 		unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1);
3859 		unlock_extent(&BTRFS_I(inode)->io_tree, destoff,
3860 			      destoff + len - 1);
3861 	}
3862 	/*
3863 	 * Truncate page cache pages so that future reads will see the cloned
3864 	 * data immediately and not the previous data.
3865 	 */
3866 	truncate_inode_pages_range(&inode->i_data, destoff,
3867 				   PAGE_CACHE_ALIGN(destoff + len) - 1);
3868 out_unlock:
3869 	if (!same_inode) {
3870 		if (inode < src) {
3871 			mutex_unlock(&src->i_mutex);
3872 			mutex_unlock(&inode->i_mutex);
3873 		} else {
3874 			mutex_unlock(&inode->i_mutex);
3875 			mutex_unlock(&src->i_mutex);
3876 		}
3877 	} else {
3878 		mutex_unlock(&src->i_mutex);
3879 	}
3880 out_fput:
3881 	fdput(src_file);
3882 out_drop_write:
3883 	mnt_drop_write_file(file);
3884 	return ret;
3885 }
3886 
3887 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
3888 {
3889 	struct btrfs_ioctl_clone_range_args args;
3890 
3891 	if (copy_from_user(&args, argp, sizeof(args)))
3892 		return -EFAULT;
3893 	return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
3894 				 args.src_length, args.dest_offset);
3895 }
3896 
3897 /*
3898  * there are many ways the trans_start and trans_end ioctls can lead
3899  * to deadlocks.  They should only be used by applications that
3900  * basically own the machine, and have a very in depth understanding
3901  * of all the possible deadlocks and enospc problems.
3902  */
3903 static long btrfs_ioctl_trans_start(struct file *file)
3904 {
3905 	struct inode *inode = file_inode(file);
3906 	struct btrfs_root *root = BTRFS_I(inode)->root;
3907 	struct btrfs_trans_handle *trans;
3908 	int ret;
3909 
3910 	ret = -EPERM;
3911 	if (!capable(CAP_SYS_ADMIN))
3912 		goto out;
3913 
3914 	ret = -EINPROGRESS;
3915 	if (file->private_data)
3916 		goto out;
3917 
3918 	ret = -EROFS;
3919 	if (btrfs_root_readonly(root))
3920 		goto out;
3921 
3922 	ret = mnt_want_write_file(file);
3923 	if (ret)
3924 		goto out;
3925 
3926 	atomic_inc(&root->fs_info->open_ioctl_trans);
3927 
3928 	ret = -ENOMEM;
3929 	trans = btrfs_start_ioctl_transaction(root);
3930 	if (IS_ERR(trans))
3931 		goto out_drop;
3932 
3933 	file->private_data = trans;
3934 	return 0;
3935 
3936 out_drop:
3937 	atomic_dec(&root->fs_info->open_ioctl_trans);
3938 	mnt_drop_write_file(file);
3939 out:
3940 	return ret;
3941 }
3942 
3943 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
3944 {
3945 	struct inode *inode = file_inode(file);
3946 	struct btrfs_root *root = BTRFS_I(inode)->root;
3947 	struct btrfs_root *new_root;
3948 	struct btrfs_dir_item *di;
3949 	struct btrfs_trans_handle *trans;
3950 	struct btrfs_path *path;
3951 	struct btrfs_key location;
3952 	struct btrfs_disk_key disk_key;
3953 	u64 objectid = 0;
3954 	u64 dir_id;
3955 	int ret;
3956 
3957 	if (!capable(CAP_SYS_ADMIN))
3958 		return -EPERM;
3959 
3960 	ret = mnt_want_write_file(file);
3961 	if (ret)
3962 		return ret;
3963 
3964 	if (copy_from_user(&objectid, argp, sizeof(objectid))) {
3965 		ret = -EFAULT;
3966 		goto out;
3967 	}
3968 
3969 	if (!objectid)
3970 		objectid = BTRFS_FS_TREE_OBJECTID;
3971 
3972 	location.objectid = objectid;
3973 	location.type = BTRFS_ROOT_ITEM_KEY;
3974 	location.offset = (u64)-1;
3975 
3976 	new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
3977 	if (IS_ERR(new_root)) {
3978 		ret = PTR_ERR(new_root);
3979 		goto out;
3980 	}
3981 
3982 	path = btrfs_alloc_path();
3983 	if (!path) {
3984 		ret = -ENOMEM;
3985 		goto out;
3986 	}
3987 	path->leave_spinning = 1;
3988 
3989 	trans = btrfs_start_transaction(root, 1);
3990 	if (IS_ERR(trans)) {
3991 		btrfs_free_path(path);
3992 		ret = PTR_ERR(trans);
3993 		goto out;
3994 	}
3995 
3996 	dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
3997 	di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
3998 				   dir_id, "default", 7, 1);
3999 	if (IS_ERR_OR_NULL(di)) {
4000 		btrfs_free_path(path);
4001 		btrfs_end_transaction(trans, root);
4002 		btrfs_err(new_root->fs_info, "Umm, you don't have the default dir"
4003 			   "item, this isn't going to work");
4004 		ret = -ENOENT;
4005 		goto out;
4006 	}
4007 
4008 	btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
4009 	btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
4010 	btrfs_mark_buffer_dirty(path->nodes[0]);
4011 	btrfs_free_path(path);
4012 
4013 	btrfs_set_fs_incompat(root->fs_info, DEFAULT_SUBVOL);
4014 	btrfs_end_transaction(trans, root);
4015 out:
4016 	mnt_drop_write_file(file);
4017 	return ret;
4018 }
4019 
4020 void btrfs_get_block_group_info(struct list_head *groups_list,
4021 				struct btrfs_ioctl_space_info *space)
4022 {
4023 	struct btrfs_block_group_cache *block_group;
4024 
4025 	space->total_bytes = 0;
4026 	space->used_bytes = 0;
4027 	space->flags = 0;
4028 	list_for_each_entry(block_group, groups_list, list) {
4029 		space->flags = block_group->flags;
4030 		space->total_bytes += block_group->key.offset;
4031 		space->used_bytes +=
4032 			btrfs_block_group_used(&block_group->item);
4033 	}
4034 }
4035 
4036 static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
4037 {
4038 	struct btrfs_ioctl_space_args space_args;
4039 	struct btrfs_ioctl_space_info space;
4040 	struct btrfs_ioctl_space_info *dest;
4041 	struct btrfs_ioctl_space_info *dest_orig;
4042 	struct btrfs_ioctl_space_info __user *user_dest;
4043 	struct btrfs_space_info *info;
4044 	u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
4045 		       BTRFS_BLOCK_GROUP_SYSTEM,
4046 		       BTRFS_BLOCK_GROUP_METADATA,
4047 		       BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
4048 	int num_types = 4;
4049 	int alloc_size;
4050 	int ret = 0;
4051 	u64 slot_count = 0;
4052 	int i, c;
4053 
4054 	if (copy_from_user(&space_args,
4055 			   (struct btrfs_ioctl_space_args __user *)arg,
4056 			   sizeof(space_args)))
4057 		return -EFAULT;
4058 
4059 	for (i = 0; i < num_types; i++) {
4060 		struct btrfs_space_info *tmp;
4061 
4062 		info = NULL;
4063 		rcu_read_lock();
4064 		list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
4065 					list) {
4066 			if (tmp->flags == types[i]) {
4067 				info = tmp;
4068 				break;
4069 			}
4070 		}
4071 		rcu_read_unlock();
4072 
4073 		if (!info)
4074 			continue;
4075 
4076 		down_read(&info->groups_sem);
4077 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4078 			if (!list_empty(&info->block_groups[c]))
4079 				slot_count++;
4080 		}
4081 		up_read(&info->groups_sem);
4082 	}
4083 
4084 	/*
4085 	 * Global block reserve, exported as a space_info
4086 	 */
4087 	slot_count++;
4088 
4089 	/* space_slots == 0 means they are asking for a count */
4090 	if (space_args.space_slots == 0) {
4091 		space_args.total_spaces = slot_count;
4092 		goto out;
4093 	}
4094 
4095 	slot_count = min_t(u64, space_args.space_slots, slot_count);
4096 
4097 	alloc_size = sizeof(*dest) * slot_count;
4098 
4099 	/* we generally have at most 6 or so space infos, one for each raid
4100 	 * level.  So, a whole page should be more than enough for everyone
4101 	 */
4102 	if (alloc_size > PAGE_CACHE_SIZE)
4103 		return -ENOMEM;
4104 
4105 	space_args.total_spaces = 0;
4106 	dest = kmalloc(alloc_size, GFP_NOFS);
4107 	if (!dest)
4108 		return -ENOMEM;
4109 	dest_orig = dest;
4110 
4111 	/* now we have a buffer to copy into */
4112 	for (i = 0; i < num_types; i++) {
4113 		struct btrfs_space_info *tmp;
4114 
4115 		if (!slot_count)
4116 			break;
4117 
4118 		info = NULL;
4119 		rcu_read_lock();
4120 		list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
4121 					list) {
4122 			if (tmp->flags == types[i]) {
4123 				info = tmp;
4124 				break;
4125 			}
4126 		}
4127 		rcu_read_unlock();
4128 
4129 		if (!info)
4130 			continue;
4131 		down_read(&info->groups_sem);
4132 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4133 			if (!list_empty(&info->block_groups[c])) {
4134 				btrfs_get_block_group_info(
4135 					&info->block_groups[c], &space);
4136 				memcpy(dest, &space, sizeof(space));
4137 				dest++;
4138 				space_args.total_spaces++;
4139 				slot_count--;
4140 			}
4141 			if (!slot_count)
4142 				break;
4143 		}
4144 		up_read(&info->groups_sem);
4145 	}
4146 
4147 	/*
4148 	 * Add global block reserve
4149 	 */
4150 	if (slot_count) {
4151 		struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv;
4152 
4153 		spin_lock(&block_rsv->lock);
4154 		space.total_bytes = block_rsv->size;
4155 		space.used_bytes = block_rsv->size - block_rsv->reserved;
4156 		spin_unlock(&block_rsv->lock);
4157 		space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
4158 		memcpy(dest, &space, sizeof(space));
4159 		space_args.total_spaces++;
4160 	}
4161 
4162 	user_dest = (struct btrfs_ioctl_space_info __user *)
4163 		(arg + sizeof(struct btrfs_ioctl_space_args));
4164 
4165 	if (copy_to_user(user_dest, dest_orig, alloc_size))
4166 		ret = -EFAULT;
4167 
4168 	kfree(dest_orig);
4169 out:
4170 	if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
4171 		ret = -EFAULT;
4172 
4173 	return ret;
4174 }
4175 
4176 /*
4177  * there are many ways the trans_start and trans_end ioctls can lead
4178  * to deadlocks.  They should only be used by applications that
4179  * basically own the machine, and have a very in depth understanding
4180  * of all the possible deadlocks and enospc problems.
4181  */
4182 long btrfs_ioctl_trans_end(struct file *file)
4183 {
4184 	struct inode *inode = file_inode(file);
4185 	struct btrfs_root *root = BTRFS_I(inode)->root;
4186 	struct btrfs_trans_handle *trans;
4187 
4188 	trans = file->private_data;
4189 	if (!trans)
4190 		return -EINVAL;
4191 	file->private_data = NULL;
4192 
4193 	btrfs_end_transaction(trans, root);
4194 
4195 	atomic_dec(&root->fs_info->open_ioctl_trans);
4196 
4197 	mnt_drop_write_file(file);
4198 	return 0;
4199 }
4200 
4201 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
4202 					    void __user *argp)
4203 {
4204 	struct btrfs_trans_handle *trans;
4205 	u64 transid;
4206 	int ret;
4207 
4208 	trans = btrfs_attach_transaction_barrier(root);
4209 	if (IS_ERR(trans)) {
4210 		if (PTR_ERR(trans) != -ENOENT)
4211 			return PTR_ERR(trans);
4212 
4213 		/* No running transaction, don't bother */
4214 		transid = root->fs_info->last_trans_committed;
4215 		goto out;
4216 	}
4217 	transid = trans->transid;
4218 	ret = btrfs_commit_transaction_async(trans, root, 0);
4219 	if (ret) {
4220 		btrfs_end_transaction(trans, root);
4221 		return ret;
4222 	}
4223 out:
4224 	if (argp)
4225 		if (copy_to_user(argp, &transid, sizeof(transid)))
4226 			return -EFAULT;
4227 	return 0;
4228 }
4229 
4230 static noinline long btrfs_ioctl_wait_sync(struct btrfs_root *root,
4231 					   void __user *argp)
4232 {
4233 	u64 transid;
4234 
4235 	if (argp) {
4236 		if (copy_from_user(&transid, argp, sizeof(transid)))
4237 			return -EFAULT;
4238 	} else {
4239 		transid = 0;  /* current trans */
4240 	}
4241 	return btrfs_wait_for_commit(root, transid);
4242 }
4243 
4244 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
4245 {
4246 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4247 	struct btrfs_ioctl_scrub_args *sa;
4248 	int ret;
4249 
4250 	if (!capable(CAP_SYS_ADMIN))
4251 		return -EPERM;
4252 
4253 	sa = memdup_user(arg, sizeof(*sa));
4254 	if (IS_ERR(sa))
4255 		return PTR_ERR(sa);
4256 
4257 	if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
4258 		ret = mnt_want_write_file(file);
4259 		if (ret)
4260 			goto out;
4261 	}
4262 
4263 	ret = btrfs_scrub_dev(root->fs_info, sa->devid, sa->start, sa->end,
4264 			      &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
4265 			      0);
4266 
4267 	if (copy_to_user(arg, sa, sizeof(*sa)))
4268 		ret = -EFAULT;
4269 
4270 	if (!(sa->flags & BTRFS_SCRUB_READONLY))
4271 		mnt_drop_write_file(file);
4272 out:
4273 	kfree(sa);
4274 	return ret;
4275 }
4276 
4277 static long btrfs_ioctl_scrub_cancel(struct btrfs_root *root, void __user *arg)
4278 {
4279 	if (!capable(CAP_SYS_ADMIN))
4280 		return -EPERM;
4281 
4282 	return btrfs_scrub_cancel(root->fs_info);
4283 }
4284 
4285 static long btrfs_ioctl_scrub_progress(struct btrfs_root *root,
4286 				       void __user *arg)
4287 {
4288 	struct btrfs_ioctl_scrub_args *sa;
4289 	int ret;
4290 
4291 	if (!capable(CAP_SYS_ADMIN))
4292 		return -EPERM;
4293 
4294 	sa = memdup_user(arg, sizeof(*sa));
4295 	if (IS_ERR(sa))
4296 		return PTR_ERR(sa);
4297 
4298 	ret = btrfs_scrub_progress(root, sa->devid, &sa->progress);
4299 
4300 	if (copy_to_user(arg, sa, sizeof(*sa)))
4301 		ret = -EFAULT;
4302 
4303 	kfree(sa);
4304 	return ret;
4305 }
4306 
4307 static long btrfs_ioctl_get_dev_stats(struct btrfs_root *root,
4308 				      void __user *arg)
4309 {
4310 	struct btrfs_ioctl_get_dev_stats *sa;
4311 	int ret;
4312 
4313 	sa = memdup_user(arg, sizeof(*sa));
4314 	if (IS_ERR(sa))
4315 		return PTR_ERR(sa);
4316 
4317 	if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
4318 		kfree(sa);
4319 		return -EPERM;
4320 	}
4321 
4322 	ret = btrfs_get_dev_stats(root, sa);
4323 
4324 	if (copy_to_user(arg, sa, sizeof(*sa)))
4325 		ret = -EFAULT;
4326 
4327 	kfree(sa);
4328 	return ret;
4329 }
4330 
4331 static long btrfs_ioctl_dev_replace(struct btrfs_root *root, void __user *arg)
4332 {
4333 	struct btrfs_ioctl_dev_replace_args *p;
4334 	int ret;
4335 
4336 	if (!capable(CAP_SYS_ADMIN))
4337 		return -EPERM;
4338 
4339 	p = memdup_user(arg, sizeof(*p));
4340 	if (IS_ERR(p))
4341 		return PTR_ERR(p);
4342 
4343 	switch (p->cmd) {
4344 	case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
4345 		if (root->fs_info->sb->s_flags & MS_RDONLY) {
4346 			ret = -EROFS;
4347 			goto out;
4348 		}
4349 		if (atomic_xchg(
4350 			&root->fs_info->mutually_exclusive_operation_running,
4351 			1)) {
4352 			ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4353 		} else {
4354 			ret = btrfs_dev_replace_start(root, p);
4355 			atomic_set(
4356 			 &root->fs_info->mutually_exclusive_operation_running,
4357 			 0);
4358 		}
4359 		break;
4360 	case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
4361 		btrfs_dev_replace_status(root->fs_info, p);
4362 		ret = 0;
4363 		break;
4364 	case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
4365 		ret = btrfs_dev_replace_cancel(root->fs_info, p);
4366 		break;
4367 	default:
4368 		ret = -EINVAL;
4369 		break;
4370 	}
4371 
4372 	if (copy_to_user(arg, p, sizeof(*p)))
4373 		ret = -EFAULT;
4374 out:
4375 	kfree(p);
4376 	return ret;
4377 }
4378 
4379 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
4380 {
4381 	int ret = 0;
4382 	int i;
4383 	u64 rel_ptr;
4384 	int size;
4385 	struct btrfs_ioctl_ino_path_args *ipa = NULL;
4386 	struct inode_fs_paths *ipath = NULL;
4387 	struct btrfs_path *path;
4388 
4389 	if (!capable(CAP_DAC_READ_SEARCH))
4390 		return -EPERM;
4391 
4392 	path = btrfs_alloc_path();
4393 	if (!path) {
4394 		ret = -ENOMEM;
4395 		goto out;
4396 	}
4397 
4398 	ipa = memdup_user(arg, sizeof(*ipa));
4399 	if (IS_ERR(ipa)) {
4400 		ret = PTR_ERR(ipa);
4401 		ipa = NULL;
4402 		goto out;
4403 	}
4404 
4405 	size = min_t(u32, ipa->size, 4096);
4406 	ipath = init_ipath(size, root, path);
4407 	if (IS_ERR(ipath)) {
4408 		ret = PTR_ERR(ipath);
4409 		ipath = NULL;
4410 		goto out;
4411 	}
4412 
4413 	ret = paths_from_inode(ipa->inum, ipath);
4414 	if (ret < 0)
4415 		goto out;
4416 
4417 	for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
4418 		rel_ptr = ipath->fspath->val[i] -
4419 			  (u64)(unsigned long)ipath->fspath->val;
4420 		ipath->fspath->val[i] = rel_ptr;
4421 	}
4422 
4423 	ret = copy_to_user((void *)(unsigned long)ipa->fspath,
4424 			   (void *)(unsigned long)ipath->fspath, size);
4425 	if (ret) {
4426 		ret = -EFAULT;
4427 		goto out;
4428 	}
4429 
4430 out:
4431 	btrfs_free_path(path);
4432 	free_ipath(ipath);
4433 	kfree(ipa);
4434 
4435 	return ret;
4436 }
4437 
4438 static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
4439 {
4440 	struct btrfs_data_container *inodes = ctx;
4441 	const size_t c = 3 * sizeof(u64);
4442 
4443 	if (inodes->bytes_left >= c) {
4444 		inodes->bytes_left -= c;
4445 		inodes->val[inodes->elem_cnt] = inum;
4446 		inodes->val[inodes->elem_cnt + 1] = offset;
4447 		inodes->val[inodes->elem_cnt + 2] = root;
4448 		inodes->elem_cnt += 3;
4449 	} else {
4450 		inodes->bytes_missing += c - inodes->bytes_left;
4451 		inodes->bytes_left = 0;
4452 		inodes->elem_missed += 3;
4453 	}
4454 
4455 	return 0;
4456 }
4457 
4458 static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
4459 					void __user *arg)
4460 {
4461 	int ret = 0;
4462 	int size;
4463 	struct btrfs_ioctl_logical_ino_args *loi;
4464 	struct btrfs_data_container *inodes = NULL;
4465 	struct btrfs_path *path = NULL;
4466 
4467 	if (!capable(CAP_SYS_ADMIN))
4468 		return -EPERM;
4469 
4470 	loi = memdup_user(arg, sizeof(*loi));
4471 	if (IS_ERR(loi)) {
4472 		ret = PTR_ERR(loi);
4473 		loi = NULL;
4474 		goto out;
4475 	}
4476 
4477 	path = btrfs_alloc_path();
4478 	if (!path) {
4479 		ret = -ENOMEM;
4480 		goto out;
4481 	}
4482 
4483 	size = min_t(u32, loi->size, 64 * 1024);
4484 	inodes = init_data_container(size);
4485 	if (IS_ERR(inodes)) {
4486 		ret = PTR_ERR(inodes);
4487 		inodes = NULL;
4488 		goto out;
4489 	}
4490 
4491 	ret = iterate_inodes_from_logical(loi->logical, root->fs_info, path,
4492 					  build_ino_list, inodes);
4493 	if (ret == -EINVAL)
4494 		ret = -ENOENT;
4495 	if (ret < 0)
4496 		goto out;
4497 
4498 	ret = copy_to_user((void *)(unsigned long)loi->inodes,
4499 			   (void *)(unsigned long)inodes, size);
4500 	if (ret)
4501 		ret = -EFAULT;
4502 
4503 out:
4504 	btrfs_free_path(path);
4505 	vfree(inodes);
4506 	kfree(loi);
4507 
4508 	return ret;
4509 }
4510 
4511 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
4512 			       struct btrfs_ioctl_balance_args *bargs)
4513 {
4514 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4515 
4516 	bargs->flags = bctl->flags;
4517 
4518 	if (atomic_read(&fs_info->balance_running))
4519 		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
4520 	if (atomic_read(&fs_info->balance_pause_req))
4521 		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
4522 	if (atomic_read(&fs_info->balance_cancel_req))
4523 		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
4524 
4525 	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
4526 	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
4527 	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
4528 
4529 	if (lock) {
4530 		spin_lock(&fs_info->balance_lock);
4531 		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4532 		spin_unlock(&fs_info->balance_lock);
4533 	} else {
4534 		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4535 	}
4536 }
4537 
4538 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
4539 {
4540 	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4541 	struct btrfs_fs_info *fs_info = root->fs_info;
4542 	struct btrfs_ioctl_balance_args *bargs;
4543 	struct btrfs_balance_control *bctl;
4544 	bool need_unlock; /* for mut. excl. ops lock */
4545 	int ret;
4546 
4547 	if (!capable(CAP_SYS_ADMIN))
4548 		return -EPERM;
4549 
4550 	ret = mnt_want_write_file(file);
4551 	if (ret)
4552 		return ret;
4553 
4554 again:
4555 	if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
4556 		mutex_lock(&fs_info->volume_mutex);
4557 		mutex_lock(&fs_info->balance_mutex);
4558 		need_unlock = true;
4559 		goto locked;
4560 	}
4561 
4562 	/*
4563 	 * mut. excl. ops lock is locked.  Three possibilites:
4564 	 *   (1) some other op is running
4565 	 *   (2) balance is running
4566 	 *   (3) balance is paused -- special case (think resume)
4567 	 */
4568 	mutex_lock(&fs_info->balance_mutex);
4569 	if (fs_info->balance_ctl) {
4570 		/* this is either (2) or (3) */
4571 		if (!atomic_read(&fs_info->balance_running)) {
4572 			mutex_unlock(&fs_info->balance_mutex);
4573 			if (!mutex_trylock(&fs_info->volume_mutex))
4574 				goto again;
4575 			mutex_lock(&fs_info->balance_mutex);
4576 
4577 			if (fs_info->balance_ctl &&
4578 			    !atomic_read(&fs_info->balance_running)) {
4579 				/* this is (3) */
4580 				need_unlock = false;
4581 				goto locked;
4582 			}
4583 
4584 			mutex_unlock(&fs_info->balance_mutex);
4585 			mutex_unlock(&fs_info->volume_mutex);
4586 			goto again;
4587 		} else {
4588 			/* this is (2) */
4589 			mutex_unlock(&fs_info->balance_mutex);
4590 			ret = -EINPROGRESS;
4591 			goto out;
4592 		}
4593 	} else {
4594 		/* this is (1) */
4595 		mutex_unlock(&fs_info->balance_mutex);
4596 		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4597 		goto out;
4598 	}
4599 
4600 locked:
4601 	BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));
4602 
4603 	if (arg) {
4604 		bargs = memdup_user(arg, sizeof(*bargs));
4605 		if (IS_ERR(bargs)) {
4606 			ret = PTR_ERR(bargs);
4607 			goto out_unlock;
4608 		}
4609 
4610 		if (bargs->flags & BTRFS_BALANCE_RESUME) {
4611 			if (!fs_info->balance_ctl) {
4612 				ret = -ENOTCONN;
4613 				goto out_bargs;
4614 			}
4615 
4616 			bctl = fs_info->balance_ctl;
4617 			spin_lock(&fs_info->balance_lock);
4618 			bctl->flags |= BTRFS_BALANCE_RESUME;
4619 			spin_unlock(&fs_info->balance_lock);
4620 
4621 			goto do_balance;
4622 		}
4623 	} else {
4624 		bargs = NULL;
4625 	}
4626 
4627 	if (fs_info->balance_ctl) {
4628 		ret = -EINPROGRESS;
4629 		goto out_bargs;
4630 	}
4631 
4632 	bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
4633 	if (!bctl) {
4634 		ret = -ENOMEM;
4635 		goto out_bargs;
4636 	}
4637 
4638 	bctl->fs_info = fs_info;
4639 	if (arg) {
4640 		memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
4641 		memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
4642 		memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
4643 
4644 		bctl->flags = bargs->flags;
4645 	} else {
4646 		/* balance everything - no filters */
4647 		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
4648 	}
4649 
4650 do_balance:
4651 	/*
4652 	 * Ownership of bctl and mutually_exclusive_operation_running
4653 	 * goes to to btrfs_balance.  bctl is freed in __cancel_balance,
4654 	 * or, if restriper was paused all the way until unmount, in
4655 	 * free_fs_info.  mutually_exclusive_operation_running is
4656 	 * cleared in __cancel_balance.
4657 	 */
4658 	need_unlock = false;
4659 
4660 	ret = btrfs_balance(bctl, bargs);
4661 
4662 	if (arg) {
4663 		if (copy_to_user(arg, bargs, sizeof(*bargs)))
4664 			ret = -EFAULT;
4665 	}
4666 
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