xref: /openbmc/linux/fs/btrfs/ioctl.c (revision c4a54f70)
1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * Copyright (C) 2007 Oracle.  All rights reserved.
4   */
5  
6  #include <linux/kernel.h>
7  #include <linux/bio.h>
8  #include <linux/file.h>
9  #include <linux/fs.h>
10  #include <linux/fsnotify.h>
11  #include <linux/pagemap.h>
12  #include <linux/highmem.h>
13  #include <linux/time.h>
14  #include <linux/string.h>
15  #include <linux/backing-dev.h>
16  #include <linux/mount.h>
17  #include <linux/namei.h>
18  #include <linux/writeback.h>
19  #include <linux/compat.h>
20  #include <linux/security.h>
21  #include <linux/xattr.h>
22  #include <linux/mm.h>
23  #include <linux/slab.h>
24  #include <linux/blkdev.h>
25  #include <linux/uuid.h>
26  #include <linux/btrfs.h>
27  #include <linux/uaccess.h>
28  #include <linux/iversion.h>
29  #include "ctree.h"
30  #include "disk-io.h"
31  #include "export.h"
32  #include "transaction.h"
33  #include "btrfs_inode.h"
34  #include "print-tree.h"
35  #include "volumes.h"
36  #include "locking.h"
37  #include "inode-map.h"
38  #include "backref.h"
39  #include "rcu-string.h"
40  #include "send.h"
41  #include "dev-replace.h"
42  #include "props.h"
43  #include "sysfs.h"
44  #include "qgroup.h"
45  #include "tree-log.h"
46  #include "compression.h"
47  #include "space-info.h"
48  #include "delalloc-space.h"
49  #include "block-group.h"
50  
51  #ifdef CONFIG_64BIT
52  /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
53   * structures are incorrect, as the timespec structure from userspace
54   * is 4 bytes too small. We define these alternatives here to teach
55   * the kernel about the 32-bit struct packing.
56   */
57  struct btrfs_ioctl_timespec_32 {
58  	__u64 sec;
59  	__u32 nsec;
60  } __attribute__ ((__packed__));
61  
62  struct btrfs_ioctl_received_subvol_args_32 {
63  	char	uuid[BTRFS_UUID_SIZE];	/* in */
64  	__u64	stransid;		/* in */
65  	__u64	rtransid;		/* out */
66  	struct btrfs_ioctl_timespec_32 stime; /* in */
67  	struct btrfs_ioctl_timespec_32 rtime; /* out */
68  	__u64	flags;			/* in */
69  	__u64	reserved[16];		/* in */
70  } __attribute__ ((__packed__));
71  
72  #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
73  				struct btrfs_ioctl_received_subvol_args_32)
74  #endif
75  
76  #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
77  struct btrfs_ioctl_send_args_32 {
78  	__s64 send_fd;			/* in */
79  	__u64 clone_sources_count;	/* in */
80  	compat_uptr_t clone_sources;	/* in */
81  	__u64 parent_root;		/* in */
82  	__u64 flags;			/* in */
83  	__u64 reserved[4];		/* in */
84  } __attribute__ ((__packed__));
85  
86  #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \
87  			       struct btrfs_ioctl_send_args_32)
88  #endif
89  
90  /* Mask out flags that are inappropriate for the given type of inode. */
91  static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
92  		unsigned int flags)
93  {
94  	if (S_ISDIR(inode->i_mode))
95  		return flags;
96  	else if (S_ISREG(inode->i_mode))
97  		return flags & ~FS_DIRSYNC_FL;
98  	else
99  		return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
100  }
101  
102  /*
103   * Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
104   * ioctl.
105   */
106  static unsigned int btrfs_inode_flags_to_fsflags(unsigned int flags)
107  {
108  	unsigned int iflags = 0;
109  
110  	if (flags & BTRFS_INODE_SYNC)
111  		iflags |= FS_SYNC_FL;
112  	if (flags & BTRFS_INODE_IMMUTABLE)
113  		iflags |= FS_IMMUTABLE_FL;
114  	if (flags & BTRFS_INODE_APPEND)
115  		iflags |= FS_APPEND_FL;
116  	if (flags & BTRFS_INODE_NODUMP)
117  		iflags |= FS_NODUMP_FL;
118  	if (flags & BTRFS_INODE_NOATIME)
119  		iflags |= FS_NOATIME_FL;
120  	if (flags & BTRFS_INODE_DIRSYNC)
121  		iflags |= FS_DIRSYNC_FL;
122  	if (flags & BTRFS_INODE_NODATACOW)
123  		iflags |= FS_NOCOW_FL;
124  
125  	if (flags & BTRFS_INODE_NOCOMPRESS)
126  		iflags |= FS_NOCOMP_FL;
127  	else if (flags & BTRFS_INODE_COMPRESS)
128  		iflags |= FS_COMPR_FL;
129  
130  	return iflags;
131  }
132  
133  /*
134   * Update inode->i_flags based on the btrfs internal flags.
135   */
136  void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
137  {
138  	struct btrfs_inode *binode = BTRFS_I(inode);
139  	unsigned int new_fl = 0;
140  
141  	if (binode->flags & BTRFS_INODE_SYNC)
142  		new_fl |= S_SYNC;
143  	if (binode->flags & BTRFS_INODE_IMMUTABLE)
144  		new_fl |= S_IMMUTABLE;
145  	if (binode->flags & BTRFS_INODE_APPEND)
146  		new_fl |= S_APPEND;
147  	if (binode->flags & BTRFS_INODE_NOATIME)
148  		new_fl |= S_NOATIME;
149  	if (binode->flags & BTRFS_INODE_DIRSYNC)
150  		new_fl |= S_DIRSYNC;
151  
152  	set_mask_bits(&inode->i_flags,
153  		      S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
154  		      new_fl);
155  }
156  
157  static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
158  {
159  	struct btrfs_inode *binode = BTRFS_I(file_inode(file));
160  	unsigned int flags = btrfs_inode_flags_to_fsflags(binode->flags);
161  
162  	if (copy_to_user(arg, &flags, sizeof(flags)))
163  		return -EFAULT;
164  	return 0;
165  }
166  
167  /* Check if @flags are a supported and valid set of FS_*_FL flags */
168  static int check_fsflags(unsigned int flags)
169  {
170  	if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
171  		      FS_NOATIME_FL | FS_NODUMP_FL | \
172  		      FS_SYNC_FL | FS_DIRSYNC_FL | \
173  		      FS_NOCOMP_FL | FS_COMPR_FL |
174  		      FS_NOCOW_FL))
175  		return -EOPNOTSUPP;
176  
177  	if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
178  		return -EINVAL;
179  
180  	return 0;
181  }
182  
183  static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
184  {
185  	struct inode *inode = file_inode(file);
186  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
187  	struct btrfs_inode *binode = BTRFS_I(inode);
188  	struct btrfs_root *root = binode->root;
189  	struct btrfs_trans_handle *trans;
190  	unsigned int fsflags, old_fsflags;
191  	int ret;
192  	const char *comp = NULL;
193  	u32 binode_flags = binode->flags;
194  
195  	if (!inode_owner_or_capable(inode))
196  		return -EPERM;
197  
198  	if (btrfs_root_readonly(root))
199  		return -EROFS;
200  
201  	if (copy_from_user(&fsflags, arg, sizeof(fsflags)))
202  		return -EFAULT;
203  
204  	ret = check_fsflags(fsflags);
205  	if (ret)
206  		return ret;
207  
208  	ret = mnt_want_write_file(file);
209  	if (ret)
210  		return ret;
211  
212  	inode_lock(inode);
213  
214  	fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
215  	old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
216  	ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
217  	if (ret)
218  		goto out_unlock;
219  
220  	if (fsflags & FS_SYNC_FL)
221  		binode_flags |= BTRFS_INODE_SYNC;
222  	else
223  		binode_flags &= ~BTRFS_INODE_SYNC;
224  	if (fsflags & FS_IMMUTABLE_FL)
225  		binode_flags |= BTRFS_INODE_IMMUTABLE;
226  	else
227  		binode_flags &= ~BTRFS_INODE_IMMUTABLE;
228  	if (fsflags & FS_APPEND_FL)
229  		binode_flags |= BTRFS_INODE_APPEND;
230  	else
231  		binode_flags &= ~BTRFS_INODE_APPEND;
232  	if (fsflags & FS_NODUMP_FL)
233  		binode_flags |= BTRFS_INODE_NODUMP;
234  	else
235  		binode_flags &= ~BTRFS_INODE_NODUMP;
236  	if (fsflags & FS_NOATIME_FL)
237  		binode_flags |= BTRFS_INODE_NOATIME;
238  	else
239  		binode_flags &= ~BTRFS_INODE_NOATIME;
240  	if (fsflags & FS_DIRSYNC_FL)
241  		binode_flags |= BTRFS_INODE_DIRSYNC;
242  	else
243  		binode_flags &= ~BTRFS_INODE_DIRSYNC;
244  	if (fsflags & FS_NOCOW_FL) {
245  		if (S_ISREG(inode->i_mode)) {
246  			/*
247  			 * It's safe to turn csums off here, no extents exist.
248  			 * Otherwise we want the flag to reflect the real COW
249  			 * status of the file and will not set it.
250  			 */
251  			if (inode->i_size == 0)
252  				binode_flags |= BTRFS_INODE_NODATACOW |
253  						BTRFS_INODE_NODATASUM;
254  		} else {
255  			binode_flags |= BTRFS_INODE_NODATACOW;
256  		}
257  	} else {
258  		/*
259  		 * Revert back under same assumptions as above
260  		 */
261  		if (S_ISREG(inode->i_mode)) {
262  			if (inode->i_size == 0)
263  				binode_flags &= ~(BTRFS_INODE_NODATACOW |
264  						  BTRFS_INODE_NODATASUM);
265  		} else {
266  			binode_flags &= ~BTRFS_INODE_NODATACOW;
267  		}
268  	}
269  
270  	/*
271  	 * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
272  	 * flag may be changed automatically if compression code won't make
273  	 * things smaller.
274  	 */
275  	if (fsflags & FS_NOCOMP_FL) {
276  		binode_flags &= ~BTRFS_INODE_COMPRESS;
277  		binode_flags |= BTRFS_INODE_NOCOMPRESS;
278  	} else if (fsflags & FS_COMPR_FL) {
279  
280  		if (IS_SWAPFILE(inode)) {
281  			ret = -ETXTBSY;
282  			goto out_unlock;
283  		}
284  
285  		binode_flags |= BTRFS_INODE_COMPRESS;
286  		binode_flags &= ~BTRFS_INODE_NOCOMPRESS;
287  
288  		comp = btrfs_compress_type2str(fs_info->compress_type);
289  		if (!comp || comp[0] == 0)
290  			comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
291  	} else {
292  		binode_flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
293  	}
294  
295  	/*
296  	 * 1 for inode item
297  	 * 2 for properties
298  	 */
299  	trans = btrfs_start_transaction(root, 3);
300  	if (IS_ERR(trans)) {
301  		ret = PTR_ERR(trans);
302  		goto out_unlock;
303  	}
304  
305  	if (comp) {
306  		ret = btrfs_set_prop(trans, inode, "btrfs.compression", comp,
307  				     strlen(comp), 0);
308  		if (ret) {
309  			btrfs_abort_transaction(trans, ret);
310  			goto out_end_trans;
311  		}
312  	} else {
313  		ret = btrfs_set_prop(trans, inode, "btrfs.compression", NULL,
314  				     0, 0);
315  		if (ret && ret != -ENODATA) {
316  			btrfs_abort_transaction(trans, ret);
317  			goto out_end_trans;
318  		}
319  	}
320  
321  	binode->flags = binode_flags;
322  	btrfs_sync_inode_flags_to_i_flags(inode);
323  	inode_inc_iversion(inode);
324  	inode->i_ctime = current_time(inode);
325  	ret = btrfs_update_inode(trans, root, inode);
326  
327   out_end_trans:
328  	btrfs_end_transaction(trans);
329   out_unlock:
330  	inode_unlock(inode);
331  	mnt_drop_write_file(file);
332  	return ret;
333  }
334  
335  /*
336   * Translate btrfs internal inode flags to xflags as expected by the
337   * FS_IOC_FSGETXATT ioctl. Filter only the supported ones, unknown flags are
338   * silently dropped.
339   */
340  static unsigned int btrfs_inode_flags_to_xflags(unsigned int flags)
341  {
342  	unsigned int xflags = 0;
343  
344  	if (flags & BTRFS_INODE_APPEND)
345  		xflags |= FS_XFLAG_APPEND;
346  	if (flags & BTRFS_INODE_IMMUTABLE)
347  		xflags |= FS_XFLAG_IMMUTABLE;
348  	if (flags & BTRFS_INODE_NOATIME)
349  		xflags |= FS_XFLAG_NOATIME;
350  	if (flags & BTRFS_INODE_NODUMP)
351  		xflags |= FS_XFLAG_NODUMP;
352  	if (flags & BTRFS_INODE_SYNC)
353  		xflags |= FS_XFLAG_SYNC;
354  
355  	return xflags;
356  }
357  
358  /* Check if @flags are a supported and valid set of FS_XFLAGS_* flags */
359  static int check_xflags(unsigned int flags)
360  {
361  	if (flags & ~(FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE | FS_XFLAG_NOATIME |
362  		      FS_XFLAG_NODUMP | FS_XFLAG_SYNC))
363  		return -EOPNOTSUPP;
364  	return 0;
365  }
366  
367  /*
368   * Set the xflags from the internal inode flags. The remaining items of fsxattr
369   * are zeroed.
370   */
371  static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
372  {
373  	struct btrfs_inode *binode = BTRFS_I(file_inode(file));
374  	struct fsxattr fa;
375  
376  	simple_fill_fsxattr(&fa, btrfs_inode_flags_to_xflags(binode->flags));
377  	if (copy_to_user(arg, &fa, sizeof(fa)))
378  		return -EFAULT;
379  
380  	return 0;
381  }
382  
383  static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
384  {
385  	struct inode *inode = file_inode(file);
386  	struct btrfs_inode *binode = BTRFS_I(inode);
387  	struct btrfs_root *root = binode->root;
388  	struct btrfs_trans_handle *trans;
389  	struct fsxattr fa, old_fa;
390  	unsigned old_flags;
391  	unsigned old_i_flags;
392  	int ret = 0;
393  
394  	if (!inode_owner_or_capable(inode))
395  		return -EPERM;
396  
397  	if (btrfs_root_readonly(root))
398  		return -EROFS;
399  
400  	if (copy_from_user(&fa, arg, sizeof(fa)))
401  		return -EFAULT;
402  
403  	ret = check_xflags(fa.fsx_xflags);
404  	if (ret)
405  		return ret;
406  
407  	if (fa.fsx_extsize != 0 || fa.fsx_projid != 0 || fa.fsx_cowextsize != 0)
408  		return -EOPNOTSUPP;
409  
410  	ret = mnt_want_write_file(file);
411  	if (ret)
412  		return ret;
413  
414  	inode_lock(inode);
415  
416  	old_flags = binode->flags;
417  	old_i_flags = inode->i_flags;
418  
419  	simple_fill_fsxattr(&old_fa,
420  			    btrfs_inode_flags_to_xflags(binode->flags));
421  	ret = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
422  	if (ret)
423  		goto out_unlock;
424  
425  	if (fa.fsx_xflags & FS_XFLAG_SYNC)
426  		binode->flags |= BTRFS_INODE_SYNC;
427  	else
428  		binode->flags &= ~BTRFS_INODE_SYNC;
429  	if (fa.fsx_xflags & FS_XFLAG_IMMUTABLE)
430  		binode->flags |= BTRFS_INODE_IMMUTABLE;
431  	else
432  		binode->flags &= ~BTRFS_INODE_IMMUTABLE;
433  	if (fa.fsx_xflags & FS_XFLAG_APPEND)
434  		binode->flags |= BTRFS_INODE_APPEND;
435  	else
436  		binode->flags &= ~BTRFS_INODE_APPEND;
437  	if (fa.fsx_xflags & FS_XFLAG_NODUMP)
438  		binode->flags |= BTRFS_INODE_NODUMP;
439  	else
440  		binode->flags &= ~BTRFS_INODE_NODUMP;
441  	if (fa.fsx_xflags & FS_XFLAG_NOATIME)
442  		binode->flags |= BTRFS_INODE_NOATIME;
443  	else
444  		binode->flags &= ~BTRFS_INODE_NOATIME;
445  
446  	/* 1 item for the inode */
447  	trans = btrfs_start_transaction(root, 1);
448  	if (IS_ERR(trans)) {
449  		ret = PTR_ERR(trans);
450  		goto out_unlock;
451  	}
452  
453  	btrfs_sync_inode_flags_to_i_flags(inode);
454  	inode_inc_iversion(inode);
455  	inode->i_ctime = current_time(inode);
456  	ret = btrfs_update_inode(trans, root, inode);
457  
458  	btrfs_end_transaction(trans);
459  
460  out_unlock:
461  	if (ret) {
462  		binode->flags = old_flags;
463  		inode->i_flags = old_i_flags;
464  	}
465  
466  	inode_unlock(inode);
467  	mnt_drop_write_file(file);
468  
469  	return ret;
470  }
471  
472  static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
473  {
474  	struct inode *inode = file_inode(file);
475  
476  	return put_user(inode->i_generation, arg);
477  }
478  
479  static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,
480  					void __user *arg)
481  {
482  	struct btrfs_device *device;
483  	struct request_queue *q;
484  	struct fstrim_range range;
485  	u64 minlen = ULLONG_MAX;
486  	u64 num_devices = 0;
487  	int ret;
488  
489  	if (!capable(CAP_SYS_ADMIN))
490  		return -EPERM;
491  
492  	/*
493  	 * If the fs is mounted with nologreplay, which requires it to be
494  	 * mounted in RO mode as well, we can not allow discard on free space
495  	 * inside block groups, because log trees refer to extents that are not
496  	 * pinned in a block group's free space cache (pinning the extents is
497  	 * precisely the first phase of replaying a log tree).
498  	 */
499  	if (btrfs_test_opt(fs_info, NOLOGREPLAY))
500  		return -EROFS;
501  
502  	rcu_read_lock();
503  	list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
504  				dev_list) {
505  		if (!device->bdev)
506  			continue;
507  		q = bdev_get_queue(device->bdev);
508  		if (blk_queue_discard(q)) {
509  			num_devices++;
510  			minlen = min_t(u64, q->limits.discard_granularity,
511  				     minlen);
512  		}
513  	}
514  	rcu_read_unlock();
515  
516  	if (!num_devices)
517  		return -EOPNOTSUPP;
518  	if (copy_from_user(&range, arg, sizeof(range)))
519  		return -EFAULT;
520  
521  	/*
522  	 * NOTE: Don't truncate the range using super->total_bytes.  Bytenr of
523  	 * block group is in the logical address space, which can be any
524  	 * sectorsize aligned bytenr in  the range [0, U64_MAX].
525  	 */
526  	if (range.len < fs_info->sb->s_blocksize)
527  		return -EINVAL;
528  
529  	range.minlen = max(range.minlen, minlen);
530  	ret = btrfs_trim_fs(fs_info, &range);
531  	if (ret < 0)
532  		return ret;
533  
534  	if (copy_to_user(arg, &range, sizeof(range)))
535  		return -EFAULT;
536  
537  	return 0;
538  }
539  
540  int __pure btrfs_is_empty_uuid(u8 *uuid)
541  {
542  	int i;
543  
544  	for (i = 0; i < BTRFS_UUID_SIZE; i++) {
545  		if (uuid[i])
546  			return 0;
547  	}
548  	return 1;
549  }
550  
551  static noinline int create_subvol(struct inode *dir,
552  				  struct dentry *dentry,
553  				  const char *name, int namelen,
554  				  struct btrfs_qgroup_inherit *inherit)
555  {
556  	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
557  	struct btrfs_trans_handle *trans;
558  	struct btrfs_key key;
559  	struct btrfs_root_item *root_item;
560  	struct btrfs_inode_item *inode_item;
561  	struct extent_buffer *leaf;
562  	struct btrfs_root *root = BTRFS_I(dir)->root;
563  	struct btrfs_root *new_root;
564  	struct btrfs_block_rsv block_rsv;
565  	struct timespec64 cur_time = current_time(dir);
566  	struct inode *inode;
567  	int ret;
568  	int err;
569  	u64 objectid;
570  	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
571  	u64 index = 0;
572  
573  	root_item = kzalloc(sizeof(*root_item), GFP_KERNEL);
574  	if (!root_item)
575  		return -ENOMEM;
576  
577  	ret = btrfs_find_free_objectid(fs_info->tree_root, &objectid);
578  	if (ret)
579  		goto fail_free;
580  
581  	/*
582  	 * Don't create subvolume whose level is not zero. Or qgroup will be
583  	 * screwed up since it assumes subvolume qgroup's level to be 0.
584  	 */
585  	if (btrfs_qgroup_level(objectid)) {
586  		ret = -ENOSPC;
587  		goto fail_free;
588  	}
589  
590  	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
591  	/*
592  	 * The same as the snapshot creation, please see the comment
593  	 * of create_snapshot().
594  	 */
595  	ret = btrfs_subvolume_reserve_metadata(root, &block_rsv, 8, false);
596  	if (ret)
597  		goto fail_free;
598  
599  	trans = btrfs_start_transaction(root, 0);
600  	if (IS_ERR(trans)) {
601  		ret = PTR_ERR(trans);
602  		btrfs_subvolume_release_metadata(fs_info, &block_rsv);
603  		goto fail_free;
604  	}
605  	trans->block_rsv = &block_rsv;
606  	trans->bytes_reserved = block_rsv.size;
607  
608  	ret = btrfs_qgroup_inherit(trans, 0, objectid, inherit);
609  	if (ret)
610  		goto fail;
611  
612  	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
613  	if (IS_ERR(leaf)) {
614  		ret = PTR_ERR(leaf);
615  		goto fail;
616  	}
617  
618  	btrfs_mark_buffer_dirty(leaf);
619  
620  	inode_item = &root_item->inode;
621  	btrfs_set_stack_inode_generation(inode_item, 1);
622  	btrfs_set_stack_inode_size(inode_item, 3);
623  	btrfs_set_stack_inode_nlink(inode_item, 1);
624  	btrfs_set_stack_inode_nbytes(inode_item,
625  				     fs_info->nodesize);
626  	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
627  
628  	btrfs_set_root_flags(root_item, 0);
629  	btrfs_set_root_limit(root_item, 0);
630  	btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
631  
632  	btrfs_set_root_bytenr(root_item, leaf->start);
633  	btrfs_set_root_generation(root_item, trans->transid);
634  	btrfs_set_root_level(root_item, 0);
635  	btrfs_set_root_refs(root_item, 1);
636  	btrfs_set_root_used(root_item, leaf->len);
637  	btrfs_set_root_last_snapshot(root_item, 0);
638  
639  	btrfs_set_root_generation_v2(root_item,
640  			btrfs_root_generation(root_item));
641  	generate_random_guid(root_item->uuid);
642  	btrfs_set_stack_timespec_sec(&root_item->otime, cur_time.tv_sec);
643  	btrfs_set_stack_timespec_nsec(&root_item->otime, cur_time.tv_nsec);
644  	root_item->ctime = root_item->otime;
645  	btrfs_set_root_ctransid(root_item, trans->transid);
646  	btrfs_set_root_otransid(root_item, trans->transid);
647  
648  	btrfs_tree_unlock(leaf);
649  	free_extent_buffer(leaf);
650  	leaf = NULL;
651  
652  	btrfs_set_root_dirid(root_item, new_dirid);
653  
654  	key.objectid = objectid;
655  	key.offset = 0;
656  	key.type = BTRFS_ROOT_ITEM_KEY;
657  	ret = btrfs_insert_root(trans, fs_info->tree_root, &key,
658  				root_item);
659  	if (ret)
660  		goto fail;
661  
662  	key.offset = (u64)-1;
663  	new_root = btrfs_get_fs_root(fs_info, objectid, true);
664  	if (IS_ERR(new_root)) {
665  		ret = PTR_ERR(new_root);
666  		btrfs_abort_transaction(trans, ret);
667  		goto fail;
668  	}
669  
670  	btrfs_record_root_in_trans(trans, new_root);
671  
672  	ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
673  	btrfs_put_root(new_root);
674  	if (ret) {
675  		/* We potentially lose an unused inode item here */
676  		btrfs_abort_transaction(trans, ret);
677  		goto fail;
678  	}
679  
680  	mutex_lock(&new_root->objectid_mutex);
681  	new_root->highest_objectid = new_dirid;
682  	mutex_unlock(&new_root->objectid_mutex);
683  
684  	/*
685  	 * insert the directory item
686  	 */
687  	ret = btrfs_set_inode_index(BTRFS_I(dir), &index);
688  	if (ret) {
689  		btrfs_abort_transaction(trans, ret);
690  		goto fail;
691  	}
692  
693  	ret = btrfs_insert_dir_item(trans, name, namelen, BTRFS_I(dir), &key,
694  				    BTRFS_FT_DIR, index);
695  	if (ret) {
696  		btrfs_abort_transaction(trans, ret);
697  		goto fail;
698  	}
699  
700  	btrfs_i_size_write(BTRFS_I(dir), dir->i_size + namelen * 2);
701  	ret = btrfs_update_inode(trans, root, dir);
702  	if (ret) {
703  		btrfs_abort_transaction(trans, ret);
704  		goto fail;
705  	}
706  
707  	ret = btrfs_add_root_ref(trans, objectid, root->root_key.objectid,
708  				 btrfs_ino(BTRFS_I(dir)), index, name, namelen);
709  	if (ret) {
710  		btrfs_abort_transaction(trans, ret);
711  		goto fail;
712  	}
713  
714  	ret = btrfs_uuid_tree_add(trans, root_item->uuid,
715  				  BTRFS_UUID_KEY_SUBVOL, objectid);
716  	if (ret)
717  		btrfs_abort_transaction(trans, ret);
718  
719  fail:
720  	kfree(root_item);
721  	trans->block_rsv = NULL;
722  	trans->bytes_reserved = 0;
723  	btrfs_subvolume_release_metadata(fs_info, &block_rsv);
724  
725  	err = btrfs_commit_transaction(trans);
726  	if (err && !ret)
727  		ret = err;
728  
729  	if (!ret) {
730  		inode = btrfs_lookup_dentry(dir, dentry);
731  		if (IS_ERR(inode))
732  			return PTR_ERR(inode);
733  		d_instantiate(dentry, inode);
734  	}
735  	return ret;
736  
737  fail_free:
738  	kfree(root_item);
739  	return ret;
740  }
741  
742  static int create_snapshot(struct btrfs_root *root, struct inode *dir,
743  			   struct dentry *dentry, bool readonly,
744  			   struct btrfs_qgroup_inherit *inherit)
745  {
746  	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
747  	struct inode *inode;
748  	struct btrfs_pending_snapshot *pending_snapshot;
749  	struct btrfs_trans_handle *trans;
750  	int ret;
751  
752  	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
753  		return -EINVAL;
754  
755  	if (atomic_read(&root->nr_swapfiles)) {
756  		btrfs_warn(fs_info,
757  			   "cannot snapshot subvolume with active swapfile");
758  		return -ETXTBSY;
759  	}
760  
761  	pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
762  	if (!pending_snapshot)
763  		return -ENOMEM;
764  
765  	pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item),
766  			GFP_KERNEL);
767  	pending_snapshot->path = btrfs_alloc_path();
768  	if (!pending_snapshot->root_item || !pending_snapshot->path) {
769  		ret = -ENOMEM;
770  		goto free_pending;
771  	}
772  
773  	btrfs_init_block_rsv(&pending_snapshot->block_rsv,
774  			     BTRFS_BLOCK_RSV_TEMP);
775  	/*
776  	 * 1 - parent dir inode
777  	 * 2 - dir entries
778  	 * 1 - root item
779  	 * 2 - root ref/backref
780  	 * 1 - root of snapshot
781  	 * 1 - UUID item
782  	 */
783  	ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
784  					&pending_snapshot->block_rsv, 8,
785  					false);
786  	if (ret)
787  		goto free_pending;
788  
789  	pending_snapshot->dentry = dentry;
790  	pending_snapshot->root = root;
791  	pending_snapshot->readonly = readonly;
792  	pending_snapshot->dir = dir;
793  	pending_snapshot->inherit = inherit;
794  
795  	trans = btrfs_start_transaction(root, 0);
796  	if (IS_ERR(trans)) {
797  		ret = PTR_ERR(trans);
798  		goto fail;
799  	}
800  
801  	spin_lock(&fs_info->trans_lock);
802  	list_add(&pending_snapshot->list,
803  		 &trans->transaction->pending_snapshots);
804  	spin_unlock(&fs_info->trans_lock);
805  
806  	ret = btrfs_commit_transaction(trans);
807  	if (ret)
808  		goto fail;
809  
810  	ret = pending_snapshot->error;
811  	if (ret)
812  		goto fail;
813  
814  	ret = btrfs_orphan_cleanup(pending_snapshot->snap);
815  	if (ret)
816  		goto fail;
817  
818  	inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
819  	if (IS_ERR(inode)) {
820  		ret = PTR_ERR(inode);
821  		goto fail;
822  	}
823  
824  	d_instantiate(dentry, inode);
825  	ret = 0;
826  fail:
827  	btrfs_put_root(pending_snapshot->snap);
828  	btrfs_subvolume_release_metadata(fs_info, &pending_snapshot->block_rsv);
829  free_pending:
830  	kfree(pending_snapshot->root_item);
831  	btrfs_free_path(pending_snapshot->path);
832  	kfree(pending_snapshot);
833  
834  	return ret;
835  }
836  
837  /*  copy of may_delete in fs/namei.c()
838   *	Check whether we can remove a link victim from directory dir, check
839   *  whether the type of victim is right.
840   *  1. We can't do it if dir is read-only (done in permission())
841   *  2. We should have write and exec permissions on dir
842   *  3. We can't remove anything from append-only dir
843   *  4. We can't do anything with immutable dir (done in permission())
844   *  5. If the sticky bit on dir is set we should either
845   *	a. be owner of dir, or
846   *	b. be owner of victim, or
847   *	c. have CAP_FOWNER capability
848   *  6. If the victim is append-only or immutable we can't do anything with
849   *     links pointing to it.
850   *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
851   *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
852   *  9. We can't remove a root or mountpoint.
853   * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
854   *     nfs_async_unlink().
855   */
856  
857  static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
858  {
859  	int error;
860  
861  	if (d_really_is_negative(victim))
862  		return -ENOENT;
863  
864  	BUG_ON(d_inode(victim->d_parent) != dir);
865  	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
866  
867  	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
868  	if (error)
869  		return error;
870  	if (IS_APPEND(dir))
871  		return -EPERM;
872  	if (check_sticky(dir, d_inode(victim)) || IS_APPEND(d_inode(victim)) ||
873  	    IS_IMMUTABLE(d_inode(victim)) || IS_SWAPFILE(d_inode(victim)))
874  		return -EPERM;
875  	if (isdir) {
876  		if (!d_is_dir(victim))
877  			return -ENOTDIR;
878  		if (IS_ROOT(victim))
879  			return -EBUSY;
880  	} else if (d_is_dir(victim))
881  		return -EISDIR;
882  	if (IS_DEADDIR(dir))
883  		return -ENOENT;
884  	if (victim->d_flags & DCACHE_NFSFS_RENAMED)
885  		return -EBUSY;
886  	return 0;
887  }
888  
889  /* copy of may_create in fs/namei.c() */
890  static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
891  {
892  	if (d_really_is_positive(child))
893  		return -EEXIST;
894  	if (IS_DEADDIR(dir))
895  		return -ENOENT;
896  	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
897  }
898  
899  /*
900   * Create a new subvolume below @parent.  This is largely modeled after
901   * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
902   * inside this filesystem so it's quite a bit simpler.
903   */
904  static noinline int btrfs_mksubvol(const struct path *parent,
905  				   const char *name, int namelen,
906  				   struct btrfs_root *snap_src,
907  				   bool readonly,
908  				   struct btrfs_qgroup_inherit *inherit)
909  {
910  	struct inode *dir = d_inode(parent->dentry);
911  	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
912  	struct dentry *dentry;
913  	int error;
914  
915  	error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
916  	if (error == -EINTR)
917  		return error;
918  
919  	dentry = lookup_one_len(name, parent->dentry, namelen);
920  	error = PTR_ERR(dentry);
921  	if (IS_ERR(dentry))
922  		goto out_unlock;
923  
924  	error = btrfs_may_create(dir, dentry);
925  	if (error)
926  		goto out_dput;
927  
928  	/*
929  	 * even if this name doesn't exist, we may get hash collisions.
930  	 * check for them now when we can safely fail
931  	 */
932  	error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
933  					       dir->i_ino, name,
934  					       namelen);
935  	if (error)
936  		goto out_dput;
937  
938  	down_read(&fs_info->subvol_sem);
939  
940  	if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
941  		goto out_up_read;
942  
943  	if (snap_src)
944  		error = create_snapshot(snap_src, dir, dentry, readonly, inherit);
945  	else
946  		error = create_subvol(dir, dentry, name, namelen, inherit);
947  
948  	if (!error)
949  		fsnotify_mkdir(dir, dentry);
950  out_up_read:
951  	up_read(&fs_info->subvol_sem);
952  out_dput:
953  	dput(dentry);
954  out_unlock:
955  	inode_unlock(dir);
956  	return error;
957  }
958  
959  static noinline int btrfs_mksnapshot(const struct path *parent,
960  				   const char *name, int namelen,
961  				   struct btrfs_root *root,
962  				   bool readonly,
963  				   struct btrfs_qgroup_inherit *inherit)
964  {
965  	int ret;
966  	bool snapshot_force_cow = false;
967  
968  	/*
969  	 * Force new buffered writes to reserve space even when NOCOW is
970  	 * possible. This is to avoid later writeback (running dealloc) to
971  	 * fallback to COW mode and unexpectedly fail with ENOSPC.
972  	 */
973  	btrfs_drew_read_lock(&root->snapshot_lock);
974  
975  	ret = btrfs_start_delalloc_snapshot(root);
976  	if (ret)
977  		goto out;
978  
979  	/*
980  	 * All previous writes have started writeback in NOCOW mode, so now
981  	 * we force future writes to fallback to COW mode during snapshot
982  	 * creation.
983  	 */
984  	atomic_inc(&root->snapshot_force_cow);
985  	snapshot_force_cow = true;
986  
987  	btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
988  
989  	ret = btrfs_mksubvol(parent, name, namelen,
990  			     root, readonly, inherit);
991  out:
992  	if (snapshot_force_cow)
993  		atomic_dec(&root->snapshot_force_cow);
994  	btrfs_drew_read_unlock(&root->snapshot_lock);
995  	return ret;
996  }
997  
998  /*
999   * When we're defragging a range, we don't want to kick it off again
1000   * if it is really just waiting for delalloc to send it down.
1001   * If we find a nice big extent or delalloc range for the bytes in the
1002   * file you want to defrag, we return 0 to let you know to skip this
1003   * part of the file
1004   */
1005  static int check_defrag_in_cache(struct inode *inode, u64 offset, u32 thresh)
1006  {
1007  	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1008  	struct extent_map *em = NULL;
1009  	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1010  	u64 end;
1011  
1012  	read_lock(&em_tree->lock);
1013  	em = lookup_extent_mapping(em_tree, offset, PAGE_SIZE);
1014  	read_unlock(&em_tree->lock);
1015  
1016  	if (em) {
1017  		end = extent_map_end(em);
1018  		free_extent_map(em);
1019  		if (end - offset > thresh)
1020  			return 0;
1021  	}
1022  	/* if we already have a nice delalloc here, just stop */
1023  	thresh /= 2;
1024  	end = count_range_bits(io_tree, &offset, offset + thresh,
1025  			       thresh, EXTENT_DELALLOC, 1);
1026  	if (end >= thresh)
1027  		return 0;
1028  	return 1;
1029  }
1030  
1031  /*
1032   * helper function to walk through a file and find extents
1033   * newer than a specific transid, and smaller than thresh.
1034   *
1035   * This is used by the defragging code to find new and small
1036   * extents
1037   */
1038  static int find_new_extents(struct btrfs_root *root,
1039  			    struct inode *inode, u64 newer_than,
1040  			    u64 *off, u32 thresh)
1041  {
1042  	struct btrfs_path *path;
1043  	struct btrfs_key min_key;
1044  	struct extent_buffer *leaf;
1045  	struct btrfs_file_extent_item *extent;
1046  	int type;
1047  	int ret;
1048  	u64 ino = btrfs_ino(BTRFS_I(inode));
1049  
1050  	path = btrfs_alloc_path();
1051  	if (!path)
1052  		return -ENOMEM;
1053  
1054  	min_key.objectid = ino;
1055  	min_key.type = BTRFS_EXTENT_DATA_KEY;
1056  	min_key.offset = *off;
1057  
1058  	while (1) {
1059  		ret = btrfs_search_forward(root, &min_key, path, newer_than);
1060  		if (ret != 0)
1061  			goto none;
1062  process_slot:
1063  		if (min_key.objectid != ino)
1064  			goto none;
1065  		if (min_key.type != BTRFS_EXTENT_DATA_KEY)
1066  			goto none;
1067  
1068  		leaf = path->nodes[0];
1069  		extent = btrfs_item_ptr(leaf, path->slots[0],
1070  					struct btrfs_file_extent_item);
1071  
1072  		type = btrfs_file_extent_type(leaf, extent);
1073  		if (type == BTRFS_FILE_EXTENT_REG &&
1074  		    btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
1075  		    check_defrag_in_cache(inode, min_key.offset, thresh)) {
1076  			*off = min_key.offset;
1077  			btrfs_free_path(path);
1078  			return 0;
1079  		}
1080  
1081  		path->slots[0]++;
1082  		if (path->slots[0] < btrfs_header_nritems(leaf)) {
1083  			btrfs_item_key_to_cpu(leaf, &min_key, path->slots[0]);
1084  			goto process_slot;
1085  		}
1086  
1087  		if (min_key.offset == (u64)-1)
1088  			goto none;
1089  
1090  		min_key.offset++;
1091  		btrfs_release_path(path);
1092  	}
1093  none:
1094  	btrfs_free_path(path);
1095  	return -ENOENT;
1096  }
1097  
1098  static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start)
1099  {
1100  	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1101  	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1102  	struct extent_map *em;
1103  	u64 len = PAGE_SIZE;
1104  
1105  	/*
1106  	 * hopefully we have this extent in the tree already, try without
1107  	 * the full extent lock
1108  	 */
1109  	read_lock(&em_tree->lock);
1110  	em = lookup_extent_mapping(em_tree, start, len);
1111  	read_unlock(&em_tree->lock);
1112  
1113  	if (!em) {
1114  		struct extent_state *cached = NULL;
1115  		u64 end = start + len - 1;
1116  
1117  		/* get the big lock and read metadata off disk */
1118  		lock_extent_bits(io_tree, start, end, &cached);
1119  		em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len);
1120  		unlock_extent_cached(io_tree, start, end, &cached);
1121  
1122  		if (IS_ERR(em))
1123  			return NULL;
1124  	}
1125  
1126  	return em;
1127  }
1128  
1129  static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
1130  {
1131  	struct extent_map *next;
1132  	bool ret = true;
1133  
1134  	/* this is the last extent */
1135  	if (em->start + em->len >= i_size_read(inode))
1136  		return false;
1137  
1138  	next = defrag_lookup_extent(inode, em->start + em->len);
1139  	if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
1140  		ret = false;
1141  	else if ((em->block_start + em->block_len == next->block_start) &&
1142  		 (em->block_len > SZ_128K && next->block_len > SZ_128K))
1143  		ret = false;
1144  
1145  	free_extent_map(next);
1146  	return ret;
1147  }
1148  
1149  static int should_defrag_range(struct inode *inode, u64 start, u32 thresh,
1150  			       u64 *last_len, u64 *skip, u64 *defrag_end,
1151  			       int compress)
1152  {
1153  	struct extent_map *em;
1154  	int ret = 1;
1155  	bool next_mergeable = true;
1156  	bool prev_mergeable = true;
1157  
1158  	/*
1159  	 * make sure that once we start defragging an extent, we keep on
1160  	 * defragging it
1161  	 */
1162  	if (start < *defrag_end)
1163  		return 1;
1164  
1165  	*skip = 0;
1166  
1167  	em = defrag_lookup_extent(inode, start);
1168  	if (!em)
1169  		return 0;
1170  
1171  	/* this will cover holes, and inline extents */
1172  	if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1173  		ret = 0;
1174  		goto out;
1175  	}
1176  
1177  	if (!*defrag_end)
1178  		prev_mergeable = false;
1179  
1180  	next_mergeable = defrag_check_next_extent(inode, em);
1181  	/*
1182  	 * we hit a real extent, if it is big or the next extent is not a
1183  	 * real extent, don't bother defragging it
1184  	 */
1185  	if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1186  	    (em->len >= thresh || (!next_mergeable && !prev_mergeable)))
1187  		ret = 0;
1188  out:
1189  	/*
1190  	 * last_len ends up being a counter of how many bytes we've defragged.
1191  	 * every time we choose not to defrag an extent, we reset *last_len
1192  	 * so that the next tiny extent will force a defrag.
1193  	 *
1194  	 * The end result of this is that tiny extents before a single big
1195  	 * extent will force at least part of that big extent to be defragged.
1196  	 */
1197  	if (ret) {
1198  		*defrag_end = extent_map_end(em);
1199  	} else {
1200  		*last_len = 0;
1201  		*skip = extent_map_end(em);
1202  		*defrag_end = 0;
1203  	}
1204  
1205  	free_extent_map(em);
1206  	return ret;
1207  }
1208  
1209  /*
1210   * it doesn't do much good to defrag one or two pages
1211   * at a time.  This pulls in a nice chunk of pages
1212   * to COW and defrag.
1213   *
1214   * It also makes sure the delalloc code has enough
1215   * dirty data to avoid making new small extents as part
1216   * of the defrag
1217   *
1218   * It's a good idea to start RA on this range
1219   * before calling this.
1220   */
1221  static int cluster_pages_for_defrag(struct inode *inode,
1222  				    struct page **pages,
1223  				    unsigned long start_index,
1224  				    unsigned long num_pages)
1225  {
1226  	unsigned long file_end;
1227  	u64 isize = i_size_read(inode);
1228  	u64 page_start;
1229  	u64 page_end;
1230  	u64 page_cnt;
1231  	int ret;
1232  	int i;
1233  	int i_done;
1234  	struct btrfs_ordered_extent *ordered;
1235  	struct extent_state *cached_state = NULL;
1236  	struct extent_io_tree *tree;
1237  	struct extent_changeset *data_reserved = NULL;
1238  	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1239  
1240  	file_end = (isize - 1) >> PAGE_SHIFT;
1241  	if (!isize || start_index > file_end)
1242  		return 0;
1243  
1244  	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1245  
1246  	ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
1247  			start_index << PAGE_SHIFT,
1248  			page_cnt << PAGE_SHIFT);
1249  	if (ret)
1250  		return ret;
1251  	i_done = 0;
1252  	tree = &BTRFS_I(inode)->io_tree;
1253  
1254  	/* step one, lock all the pages */
1255  	for (i = 0; i < page_cnt; i++) {
1256  		struct page *page;
1257  again:
1258  		page = find_or_create_page(inode->i_mapping,
1259  					   start_index + i, mask);
1260  		if (!page)
1261  			break;
1262  
1263  		page_start = page_offset(page);
1264  		page_end = page_start + PAGE_SIZE - 1;
1265  		while (1) {
1266  			lock_extent_bits(tree, page_start, page_end,
1267  					 &cached_state);
1268  			ordered = btrfs_lookup_ordered_extent(inode,
1269  							      page_start);
1270  			unlock_extent_cached(tree, page_start, page_end,
1271  					     &cached_state);
1272  			if (!ordered)
1273  				break;
1274  
1275  			unlock_page(page);
1276  			btrfs_start_ordered_extent(inode, ordered, 1);
1277  			btrfs_put_ordered_extent(ordered);
1278  			lock_page(page);
1279  			/*
1280  			 * we unlocked the page above, so we need check if
1281  			 * it was released or not.
1282  			 */
1283  			if (page->mapping != inode->i_mapping) {
1284  				unlock_page(page);
1285  				put_page(page);
1286  				goto again;
1287  			}
1288  		}
1289  
1290  		if (!PageUptodate(page)) {
1291  			btrfs_readpage(NULL, page);
1292  			lock_page(page);
1293  			if (!PageUptodate(page)) {
1294  				unlock_page(page);
1295  				put_page(page);
1296  				ret = -EIO;
1297  				break;
1298  			}
1299  		}
1300  
1301  		if (page->mapping != inode->i_mapping) {
1302  			unlock_page(page);
1303  			put_page(page);
1304  			goto again;
1305  		}
1306  
1307  		pages[i] = page;
1308  		i_done++;
1309  	}
1310  	if (!i_done || ret)
1311  		goto out;
1312  
1313  	if (!(inode->i_sb->s_flags & SB_ACTIVE))
1314  		goto out;
1315  
1316  	/*
1317  	 * so now we have a nice long stream of locked
1318  	 * and up to date pages, lets wait on them
1319  	 */
1320  	for (i = 0; i < i_done; i++)
1321  		wait_on_page_writeback(pages[i]);
1322  
1323  	page_start = page_offset(pages[0]);
1324  	page_end = page_offset(pages[i_done - 1]) + PAGE_SIZE;
1325  
1326  	lock_extent_bits(&BTRFS_I(inode)->io_tree,
1327  			 page_start, page_end - 1, &cached_state);
1328  	clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1329  			  page_end - 1, EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
1330  			  EXTENT_DEFRAG, 0, 0, &cached_state);
1331  
1332  	if (i_done != page_cnt) {
1333  		spin_lock(&BTRFS_I(inode)->lock);
1334  		btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
1335  		spin_unlock(&BTRFS_I(inode)->lock);
1336  		btrfs_delalloc_release_space(inode, data_reserved,
1337  				start_index << PAGE_SHIFT,
1338  				(page_cnt - i_done) << PAGE_SHIFT, true);
1339  	}
1340  
1341  
1342  	set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1343  			  &cached_state);
1344  
1345  	unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1346  			     page_start, page_end - 1, &cached_state);
1347  
1348  	for (i = 0; i < i_done; i++) {
1349  		clear_page_dirty_for_io(pages[i]);
1350  		ClearPageChecked(pages[i]);
1351  		set_page_extent_mapped(pages[i]);
1352  		set_page_dirty(pages[i]);
1353  		unlock_page(pages[i]);
1354  		put_page(pages[i]);
1355  	}
1356  	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT);
1357  	extent_changeset_free(data_reserved);
1358  	return i_done;
1359  out:
1360  	for (i = 0; i < i_done; i++) {
1361  		unlock_page(pages[i]);
1362  		put_page(pages[i]);
1363  	}
1364  	btrfs_delalloc_release_space(inode, data_reserved,
1365  			start_index << PAGE_SHIFT,
1366  			page_cnt << PAGE_SHIFT, true);
1367  	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT);
1368  	extent_changeset_free(data_reserved);
1369  	return ret;
1370  
1371  }
1372  
1373  int btrfs_defrag_file(struct inode *inode, struct file *file,
1374  		      struct btrfs_ioctl_defrag_range_args *range,
1375  		      u64 newer_than, unsigned long max_to_defrag)
1376  {
1377  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1378  	struct btrfs_root *root = BTRFS_I(inode)->root;
1379  	struct file_ra_state *ra = NULL;
1380  	unsigned long last_index;
1381  	u64 isize = i_size_read(inode);
1382  	u64 last_len = 0;
1383  	u64 skip = 0;
1384  	u64 defrag_end = 0;
1385  	u64 newer_off = range->start;
1386  	unsigned long i;
1387  	unsigned long ra_index = 0;
1388  	int ret;
1389  	int defrag_count = 0;
1390  	int compress_type = BTRFS_COMPRESS_ZLIB;
1391  	u32 extent_thresh = range->extent_thresh;
1392  	unsigned long max_cluster = SZ_256K >> PAGE_SHIFT;
1393  	unsigned long cluster = max_cluster;
1394  	u64 new_align = ~((u64)SZ_128K - 1);
1395  	struct page **pages = NULL;
1396  	bool do_compress = range->flags & BTRFS_DEFRAG_RANGE_COMPRESS;
1397  
1398  	if (isize == 0)
1399  		return 0;
1400  
1401  	if (range->start >= isize)
1402  		return -EINVAL;
1403  
1404  	if (do_compress) {
1405  		if (range->compress_type >= BTRFS_NR_COMPRESS_TYPES)
1406  			return -EINVAL;
1407  		if (range->compress_type)
1408  			compress_type = range->compress_type;
1409  	}
1410  
1411  	if (extent_thresh == 0)
1412  		extent_thresh = SZ_256K;
1413  
1414  	/*
1415  	 * If we were not given a file, allocate a readahead context. As
1416  	 * readahead is just an optimization, defrag will work without it so
1417  	 * we don't error out.
1418  	 */
1419  	if (!file) {
1420  		ra = kzalloc(sizeof(*ra), GFP_KERNEL);
1421  		if (ra)
1422  			file_ra_state_init(ra, inode->i_mapping);
1423  	} else {
1424  		ra = &file->f_ra;
1425  	}
1426  
1427  	pages = kmalloc_array(max_cluster, sizeof(struct page *), GFP_KERNEL);
1428  	if (!pages) {
1429  		ret = -ENOMEM;
1430  		goto out_ra;
1431  	}
1432  
1433  	/* find the last page to defrag */
1434  	if (range->start + range->len > range->start) {
1435  		last_index = min_t(u64, isize - 1,
1436  			 range->start + range->len - 1) >> PAGE_SHIFT;
1437  	} else {
1438  		last_index = (isize - 1) >> PAGE_SHIFT;
1439  	}
1440  
1441  	if (newer_than) {
1442  		ret = find_new_extents(root, inode, newer_than,
1443  				       &newer_off, SZ_64K);
1444  		if (!ret) {
1445  			range->start = newer_off;
1446  			/*
1447  			 * we always align our defrag to help keep
1448  			 * the extents in the file evenly spaced
1449  			 */
1450  			i = (newer_off & new_align) >> PAGE_SHIFT;
1451  		} else
1452  			goto out_ra;
1453  	} else {
1454  		i = range->start >> PAGE_SHIFT;
1455  	}
1456  	if (!max_to_defrag)
1457  		max_to_defrag = last_index - i + 1;
1458  
1459  	/*
1460  	 * make writeback starts from i, so the defrag range can be
1461  	 * written sequentially.
1462  	 */
1463  	if (i < inode->i_mapping->writeback_index)
1464  		inode->i_mapping->writeback_index = i;
1465  
1466  	while (i <= last_index && defrag_count < max_to_defrag &&
1467  	       (i < DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE))) {
1468  		/*
1469  		 * make sure we stop running if someone unmounts
1470  		 * the FS
1471  		 */
1472  		if (!(inode->i_sb->s_flags & SB_ACTIVE))
1473  			break;
1474  
1475  		if (btrfs_defrag_cancelled(fs_info)) {
1476  			btrfs_debug(fs_info, "defrag_file cancelled");
1477  			ret = -EAGAIN;
1478  			break;
1479  		}
1480  
1481  		if (!should_defrag_range(inode, (u64)i << PAGE_SHIFT,
1482  					 extent_thresh, &last_len, &skip,
1483  					 &defrag_end, do_compress)){
1484  			unsigned long next;
1485  			/*
1486  			 * the should_defrag function tells us how much to skip
1487  			 * bump our counter by the suggested amount
1488  			 */
1489  			next = DIV_ROUND_UP(skip, PAGE_SIZE);
1490  			i = max(i + 1, next);
1491  			continue;
1492  		}
1493  
1494  		if (!newer_than) {
1495  			cluster = (PAGE_ALIGN(defrag_end) >>
1496  				   PAGE_SHIFT) - i;
1497  			cluster = min(cluster, max_cluster);
1498  		} else {
1499  			cluster = max_cluster;
1500  		}
1501  
1502  		if (i + cluster > ra_index) {
1503  			ra_index = max(i, ra_index);
1504  			if (ra)
1505  				page_cache_sync_readahead(inode->i_mapping, ra,
1506  						file, ra_index, cluster);
1507  			ra_index += cluster;
1508  		}
1509  
1510  		inode_lock(inode);
1511  		if (IS_SWAPFILE(inode)) {
1512  			ret = -ETXTBSY;
1513  		} else {
1514  			if (do_compress)
1515  				BTRFS_I(inode)->defrag_compress = compress_type;
1516  			ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1517  		}
1518  		if (ret < 0) {
1519  			inode_unlock(inode);
1520  			goto out_ra;
1521  		}
1522  
1523  		defrag_count += ret;
1524  		balance_dirty_pages_ratelimited(inode->i_mapping);
1525  		inode_unlock(inode);
1526  
1527  		if (newer_than) {
1528  			if (newer_off == (u64)-1)
1529  				break;
1530  
1531  			if (ret > 0)
1532  				i += ret;
1533  
1534  			newer_off = max(newer_off + 1,
1535  					(u64)i << PAGE_SHIFT);
1536  
1537  			ret = find_new_extents(root, inode, newer_than,
1538  					       &newer_off, SZ_64K);
1539  			if (!ret) {
1540  				range->start = newer_off;
1541  				i = (newer_off & new_align) >> PAGE_SHIFT;
1542  			} else {
1543  				break;
1544  			}
1545  		} else {
1546  			if (ret > 0) {
1547  				i += ret;
1548  				last_len += ret << PAGE_SHIFT;
1549  			} else {
1550  				i++;
1551  				last_len = 0;
1552  			}
1553  		}
1554  	}
1555  
1556  	if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1557  		filemap_flush(inode->i_mapping);
1558  		if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1559  			     &BTRFS_I(inode)->runtime_flags))
1560  			filemap_flush(inode->i_mapping);
1561  	}
1562  
1563  	if (range->compress_type == BTRFS_COMPRESS_LZO) {
1564  		btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
1565  	} else if (range->compress_type == BTRFS_COMPRESS_ZSTD) {
1566  		btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
1567  	}
1568  
1569  	ret = defrag_count;
1570  
1571  out_ra:
1572  	if (do_compress) {
1573  		inode_lock(inode);
1574  		BTRFS_I(inode)->defrag_compress = BTRFS_COMPRESS_NONE;
1575  		inode_unlock(inode);
1576  	}
1577  	if (!file)
1578  		kfree(ra);
1579  	kfree(pages);
1580  	return ret;
1581  }
1582  
1583  static noinline int btrfs_ioctl_resize(struct file *file,
1584  					void __user *arg)
1585  {
1586  	struct inode *inode = file_inode(file);
1587  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1588  	u64 new_size;
1589  	u64 old_size;
1590  	u64 devid = 1;
1591  	struct btrfs_root *root = BTRFS_I(inode)->root;
1592  	struct btrfs_ioctl_vol_args *vol_args;
1593  	struct btrfs_trans_handle *trans;
1594  	struct btrfs_device *device = NULL;
1595  	char *sizestr;
1596  	char *retptr;
1597  	char *devstr = NULL;
1598  	int ret = 0;
1599  	int mod = 0;
1600  
1601  	if (!capable(CAP_SYS_ADMIN))
1602  		return -EPERM;
1603  
1604  	ret = mnt_want_write_file(file);
1605  	if (ret)
1606  		return ret;
1607  
1608  	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
1609  		mnt_drop_write_file(file);
1610  		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1611  	}
1612  
1613  	vol_args = memdup_user(arg, sizeof(*vol_args));
1614  	if (IS_ERR(vol_args)) {
1615  		ret = PTR_ERR(vol_args);
1616  		goto out;
1617  	}
1618  
1619  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1620  
1621  	sizestr = vol_args->name;
1622  	devstr = strchr(sizestr, ':');
1623  	if (devstr) {
1624  		sizestr = devstr + 1;
1625  		*devstr = '\0';
1626  		devstr = vol_args->name;
1627  		ret = kstrtoull(devstr, 10, &devid);
1628  		if (ret)
1629  			goto out_free;
1630  		if (!devid) {
1631  			ret = -EINVAL;
1632  			goto out_free;
1633  		}
1634  		btrfs_info(fs_info, "resizing devid %llu", devid);
1635  	}
1636  
1637  	device = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
1638  	if (!device) {
1639  		btrfs_info(fs_info, "resizer unable to find device %llu",
1640  			   devid);
1641  		ret = -ENODEV;
1642  		goto out_free;
1643  	}
1644  
1645  	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
1646  		btrfs_info(fs_info,
1647  			   "resizer unable to apply on readonly device %llu",
1648  		       devid);
1649  		ret = -EPERM;
1650  		goto out_free;
1651  	}
1652  
1653  	if (!strcmp(sizestr, "max"))
1654  		new_size = device->bdev->bd_inode->i_size;
1655  	else {
1656  		if (sizestr[0] == '-') {
1657  			mod = -1;
1658  			sizestr++;
1659  		} else if (sizestr[0] == '+') {
1660  			mod = 1;
1661  			sizestr++;
1662  		}
1663  		new_size = memparse(sizestr, &retptr);
1664  		if (*retptr != '\0' || new_size == 0) {
1665  			ret = -EINVAL;
1666  			goto out_free;
1667  		}
1668  	}
1669  
1670  	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
1671  		ret = -EPERM;
1672  		goto out_free;
1673  	}
1674  
1675  	old_size = btrfs_device_get_total_bytes(device);
1676  
1677  	if (mod < 0) {
1678  		if (new_size > old_size) {
1679  			ret = -EINVAL;
1680  			goto out_free;
1681  		}
1682  		new_size = old_size - new_size;
1683  	} else if (mod > 0) {
1684  		if (new_size > ULLONG_MAX - old_size) {
1685  			ret = -ERANGE;
1686  			goto out_free;
1687  		}
1688  		new_size = old_size + new_size;
1689  	}
1690  
1691  	if (new_size < SZ_256M) {
1692  		ret = -EINVAL;
1693  		goto out_free;
1694  	}
1695  	if (new_size > device->bdev->bd_inode->i_size) {
1696  		ret = -EFBIG;
1697  		goto out_free;
1698  	}
1699  
1700  	new_size = round_down(new_size, fs_info->sectorsize);
1701  
1702  	if (new_size > old_size) {
1703  		trans = btrfs_start_transaction(root, 0);
1704  		if (IS_ERR(trans)) {
1705  			ret = PTR_ERR(trans);
1706  			goto out_free;
1707  		}
1708  		ret = btrfs_grow_device(trans, device, new_size);
1709  		btrfs_commit_transaction(trans);
1710  	} else if (new_size < old_size) {
1711  		ret = btrfs_shrink_device(device, new_size);
1712  	} /* equal, nothing need to do */
1713  
1714  	if (ret == 0 && new_size != old_size)
1715  		btrfs_info_in_rcu(fs_info,
1716  			"resize device %s (devid %llu) from %llu to %llu",
1717  			rcu_str_deref(device->name), device->devid,
1718  			old_size, new_size);
1719  out_free:
1720  	kfree(vol_args);
1721  out:
1722  	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
1723  	mnt_drop_write_file(file);
1724  	return ret;
1725  }
1726  
1727  static noinline int __btrfs_ioctl_snap_create(struct file *file,
1728  				const char *name, unsigned long fd, int subvol,
1729  				bool readonly,
1730  				struct btrfs_qgroup_inherit *inherit)
1731  {
1732  	int namelen;
1733  	int ret = 0;
1734  
1735  	if (!S_ISDIR(file_inode(file)->i_mode))
1736  		return -ENOTDIR;
1737  
1738  	ret = mnt_want_write_file(file);
1739  	if (ret)
1740  		goto out;
1741  
1742  	namelen = strlen(name);
1743  	if (strchr(name, '/')) {
1744  		ret = -EINVAL;
1745  		goto out_drop_write;
1746  	}
1747  
1748  	if (name[0] == '.' &&
1749  	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1750  		ret = -EEXIST;
1751  		goto out_drop_write;
1752  	}
1753  
1754  	if (subvol) {
1755  		ret = btrfs_mksubvol(&file->f_path, name, namelen,
1756  				     NULL, readonly, inherit);
1757  	} else {
1758  		struct fd src = fdget(fd);
1759  		struct inode *src_inode;
1760  		if (!src.file) {
1761  			ret = -EINVAL;
1762  			goto out_drop_write;
1763  		}
1764  
1765  		src_inode = file_inode(src.file);
1766  		if (src_inode->i_sb != file_inode(file)->i_sb) {
1767  			btrfs_info(BTRFS_I(file_inode(file))->root->fs_info,
1768  				   "Snapshot src from another FS");
1769  			ret = -EXDEV;
1770  		} else if (!inode_owner_or_capable(src_inode)) {
1771  			/*
1772  			 * Subvolume creation is not restricted, but snapshots
1773  			 * are limited to own subvolumes only
1774  			 */
1775  			ret = -EPERM;
1776  		} else {
1777  			ret = btrfs_mksnapshot(&file->f_path, name, namelen,
1778  					     BTRFS_I(src_inode)->root,
1779  					     readonly, inherit);
1780  		}
1781  		fdput(src);
1782  	}
1783  out_drop_write:
1784  	mnt_drop_write_file(file);
1785  out:
1786  	return ret;
1787  }
1788  
1789  static noinline int btrfs_ioctl_snap_create(struct file *file,
1790  					    void __user *arg, int subvol)
1791  {
1792  	struct btrfs_ioctl_vol_args *vol_args;
1793  	int ret;
1794  
1795  	if (!S_ISDIR(file_inode(file)->i_mode))
1796  		return -ENOTDIR;
1797  
1798  	vol_args = memdup_user(arg, sizeof(*vol_args));
1799  	if (IS_ERR(vol_args))
1800  		return PTR_ERR(vol_args);
1801  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1802  
1803  	ret = __btrfs_ioctl_snap_create(file, vol_args->name, vol_args->fd,
1804  					subvol, false, NULL);
1805  
1806  	kfree(vol_args);
1807  	return ret;
1808  }
1809  
1810  static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1811  					       void __user *arg, int subvol)
1812  {
1813  	struct btrfs_ioctl_vol_args_v2 *vol_args;
1814  	int ret;
1815  	bool readonly = false;
1816  	struct btrfs_qgroup_inherit *inherit = NULL;
1817  
1818  	if (!S_ISDIR(file_inode(file)->i_mode))
1819  		return -ENOTDIR;
1820  
1821  	vol_args = memdup_user(arg, sizeof(*vol_args));
1822  	if (IS_ERR(vol_args))
1823  		return PTR_ERR(vol_args);
1824  	vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1825  
1826  	if (vol_args->flags & ~BTRFS_SUBVOL_CREATE_ARGS_MASK) {
1827  		ret = -EOPNOTSUPP;
1828  		goto free_args;
1829  	}
1830  
1831  	if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1832  		readonly = true;
1833  	if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1834  		if (vol_args->size > PAGE_SIZE) {
1835  			ret = -EINVAL;
1836  			goto free_args;
1837  		}
1838  		inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1839  		if (IS_ERR(inherit)) {
1840  			ret = PTR_ERR(inherit);
1841  			goto free_args;
1842  		}
1843  	}
1844  
1845  	ret = __btrfs_ioctl_snap_create(file, vol_args->name, vol_args->fd,
1846  					subvol, readonly, inherit);
1847  	if (ret)
1848  		goto free_inherit;
1849  free_inherit:
1850  	kfree(inherit);
1851  free_args:
1852  	kfree(vol_args);
1853  	return ret;
1854  }
1855  
1856  static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1857  						void __user *arg)
1858  {
1859  	struct inode *inode = file_inode(file);
1860  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1861  	struct btrfs_root *root = BTRFS_I(inode)->root;
1862  	int ret = 0;
1863  	u64 flags = 0;
1864  
1865  	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID)
1866  		return -EINVAL;
1867  
1868  	down_read(&fs_info->subvol_sem);
1869  	if (btrfs_root_readonly(root))
1870  		flags |= BTRFS_SUBVOL_RDONLY;
1871  	up_read(&fs_info->subvol_sem);
1872  
1873  	if (copy_to_user(arg, &flags, sizeof(flags)))
1874  		ret = -EFAULT;
1875  
1876  	return ret;
1877  }
1878  
1879  static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1880  					      void __user *arg)
1881  {
1882  	struct inode *inode = file_inode(file);
1883  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1884  	struct btrfs_root *root = BTRFS_I(inode)->root;
1885  	struct btrfs_trans_handle *trans;
1886  	u64 root_flags;
1887  	u64 flags;
1888  	int ret = 0;
1889  
1890  	if (!inode_owner_or_capable(inode))
1891  		return -EPERM;
1892  
1893  	ret = mnt_want_write_file(file);
1894  	if (ret)
1895  		goto out;
1896  
1897  	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1898  		ret = -EINVAL;
1899  		goto out_drop_write;
1900  	}
1901  
1902  	if (copy_from_user(&flags, arg, sizeof(flags))) {
1903  		ret = -EFAULT;
1904  		goto out_drop_write;
1905  	}
1906  
1907  	if (flags & ~BTRFS_SUBVOL_RDONLY) {
1908  		ret = -EOPNOTSUPP;
1909  		goto out_drop_write;
1910  	}
1911  
1912  	down_write(&fs_info->subvol_sem);
1913  
1914  	/* nothing to do */
1915  	if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1916  		goto out_drop_sem;
1917  
1918  	root_flags = btrfs_root_flags(&root->root_item);
1919  	if (flags & BTRFS_SUBVOL_RDONLY) {
1920  		btrfs_set_root_flags(&root->root_item,
1921  				     root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1922  	} else {
1923  		/*
1924  		 * Block RO -> RW transition if this subvolume is involved in
1925  		 * send
1926  		 */
1927  		spin_lock(&root->root_item_lock);
1928  		if (root->send_in_progress == 0) {
1929  			btrfs_set_root_flags(&root->root_item,
1930  				     root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1931  			spin_unlock(&root->root_item_lock);
1932  		} else {
1933  			spin_unlock(&root->root_item_lock);
1934  			btrfs_warn(fs_info,
1935  				   "Attempt to set subvolume %llu read-write during send",
1936  				   root->root_key.objectid);
1937  			ret = -EPERM;
1938  			goto out_drop_sem;
1939  		}
1940  	}
1941  
1942  	trans = btrfs_start_transaction(root, 1);
1943  	if (IS_ERR(trans)) {
1944  		ret = PTR_ERR(trans);
1945  		goto out_reset;
1946  	}
1947  
1948  	ret = btrfs_update_root(trans, fs_info->tree_root,
1949  				&root->root_key, &root->root_item);
1950  	if (ret < 0) {
1951  		btrfs_end_transaction(trans);
1952  		goto out_reset;
1953  	}
1954  
1955  	ret = btrfs_commit_transaction(trans);
1956  
1957  out_reset:
1958  	if (ret)
1959  		btrfs_set_root_flags(&root->root_item, root_flags);
1960  out_drop_sem:
1961  	up_write(&fs_info->subvol_sem);
1962  out_drop_write:
1963  	mnt_drop_write_file(file);
1964  out:
1965  	return ret;
1966  }
1967  
1968  static noinline int key_in_sk(struct btrfs_key *key,
1969  			      struct btrfs_ioctl_search_key *sk)
1970  {
1971  	struct btrfs_key test;
1972  	int ret;
1973  
1974  	test.objectid = sk->min_objectid;
1975  	test.type = sk->min_type;
1976  	test.offset = sk->min_offset;
1977  
1978  	ret = btrfs_comp_cpu_keys(key, &test);
1979  	if (ret < 0)
1980  		return 0;
1981  
1982  	test.objectid = sk->max_objectid;
1983  	test.type = sk->max_type;
1984  	test.offset = sk->max_offset;
1985  
1986  	ret = btrfs_comp_cpu_keys(key, &test);
1987  	if (ret > 0)
1988  		return 0;
1989  	return 1;
1990  }
1991  
1992  static noinline int copy_to_sk(struct btrfs_path *path,
1993  			       struct btrfs_key *key,
1994  			       struct btrfs_ioctl_search_key *sk,
1995  			       size_t *buf_size,
1996  			       char __user *ubuf,
1997  			       unsigned long *sk_offset,
1998  			       int *num_found)
1999  {
2000  	u64 found_transid;
2001  	struct extent_buffer *leaf;
2002  	struct btrfs_ioctl_search_header sh;
2003  	struct btrfs_key test;
2004  	unsigned long item_off;
2005  	unsigned long item_len;
2006  	int nritems;
2007  	int i;
2008  	int slot;
2009  	int ret = 0;
2010  
2011  	leaf = path->nodes[0];
2012  	slot = path->slots[0];
2013  	nritems = btrfs_header_nritems(leaf);
2014  
2015  	if (btrfs_header_generation(leaf) > sk->max_transid) {
2016  		i = nritems;
2017  		goto advance_key;
2018  	}
2019  	found_transid = btrfs_header_generation(leaf);
2020  
2021  	for (i = slot; i < nritems; i++) {
2022  		item_off = btrfs_item_ptr_offset(leaf, i);
2023  		item_len = btrfs_item_size_nr(leaf, i);
2024  
2025  		btrfs_item_key_to_cpu(leaf, key, i);
2026  		if (!key_in_sk(key, sk))
2027  			continue;
2028  
2029  		if (sizeof(sh) + item_len > *buf_size) {
2030  			if (*num_found) {
2031  				ret = 1;
2032  				goto out;
2033  			}
2034  
2035  			/*
2036  			 * return one empty item back for v1, which does not
2037  			 * handle -EOVERFLOW
2038  			 */
2039  
2040  			*buf_size = sizeof(sh) + item_len;
2041  			item_len = 0;
2042  			ret = -EOVERFLOW;
2043  		}
2044  
2045  		if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
2046  			ret = 1;
2047  			goto out;
2048  		}
2049  
2050  		sh.objectid = key->objectid;
2051  		sh.offset = key->offset;
2052  		sh.type = key->type;
2053  		sh.len = item_len;
2054  		sh.transid = found_transid;
2055  
2056  		/* copy search result header */
2057  		if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
2058  			ret = -EFAULT;
2059  			goto out;
2060  		}
2061  
2062  		*sk_offset += sizeof(sh);
2063  
2064  		if (item_len) {
2065  			char __user *up = ubuf + *sk_offset;
2066  			/* copy the item */
2067  			if (read_extent_buffer_to_user(leaf, up,
2068  						       item_off, item_len)) {
2069  				ret = -EFAULT;
2070  				goto out;
2071  			}
2072  
2073  			*sk_offset += item_len;
2074  		}
2075  		(*num_found)++;
2076  
2077  		if (ret) /* -EOVERFLOW from above */
2078  			goto out;
2079  
2080  		if (*num_found >= sk->nr_items) {
2081  			ret = 1;
2082  			goto out;
2083  		}
2084  	}
2085  advance_key:
2086  	ret = 0;
2087  	test.objectid = sk->max_objectid;
2088  	test.type = sk->max_type;
2089  	test.offset = sk->max_offset;
2090  	if (btrfs_comp_cpu_keys(key, &test) >= 0)
2091  		ret = 1;
2092  	else if (key->offset < (u64)-1)
2093  		key->offset++;
2094  	else if (key->type < (u8)-1) {
2095  		key->offset = 0;
2096  		key->type++;
2097  	} else if (key->objectid < (u64)-1) {
2098  		key->offset = 0;
2099  		key->type = 0;
2100  		key->objectid++;
2101  	} else
2102  		ret = 1;
2103  out:
2104  	/*
2105  	 *  0: all items from this leaf copied, continue with next
2106  	 *  1: * more items can be copied, but unused buffer is too small
2107  	 *     * all items were found
2108  	 *     Either way, it will stops the loop which iterates to the next
2109  	 *     leaf
2110  	 *  -EOVERFLOW: item was to large for buffer
2111  	 *  -EFAULT: could not copy extent buffer back to userspace
2112  	 */
2113  	return ret;
2114  }
2115  
2116  static noinline int search_ioctl(struct inode *inode,
2117  				 struct btrfs_ioctl_search_key *sk,
2118  				 size_t *buf_size,
2119  				 char __user *ubuf)
2120  {
2121  	struct btrfs_fs_info *info = btrfs_sb(inode->i_sb);
2122  	struct btrfs_root *root;
2123  	struct btrfs_key key;
2124  	struct btrfs_path *path;
2125  	int ret;
2126  	int num_found = 0;
2127  	unsigned long sk_offset = 0;
2128  
2129  	if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
2130  		*buf_size = sizeof(struct btrfs_ioctl_search_header);
2131  		return -EOVERFLOW;
2132  	}
2133  
2134  	path = btrfs_alloc_path();
2135  	if (!path)
2136  		return -ENOMEM;
2137  
2138  	if (sk->tree_id == 0) {
2139  		/* search the root of the inode that was passed */
2140  		root = btrfs_grab_root(BTRFS_I(inode)->root);
2141  	} else {
2142  		root = btrfs_get_fs_root(info, sk->tree_id, true);
2143  		if (IS_ERR(root)) {
2144  			btrfs_free_path(path);
2145  			return PTR_ERR(root);
2146  		}
2147  	}
2148  
2149  	key.objectid = sk->min_objectid;
2150  	key.type = sk->min_type;
2151  	key.offset = sk->min_offset;
2152  
2153  	while (1) {
2154  		ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2155  		if (ret != 0) {
2156  			if (ret > 0)
2157  				ret = 0;
2158  			goto err;
2159  		}
2160  		ret = copy_to_sk(path, &key, sk, buf_size, ubuf,
2161  				 &sk_offset, &num_found);
2162  		btrfs_release_path(path);
2163  		if (ret)
2164  			break;
2165  
2166  	}
2167  	if (ret > 0)
2168  		ret = 0;
2169  err:
2170  	sk->nr_items = num_found;
2171  	btrfs_put_root(root);
2172  	btrfs_free_path(path);
2173  	return ret;
2174  }
2175  
2176  static noinline int btrfs_ioctl_tree_search(struct file *file,
2177  					   void __user *argp)
2178  {
2179  	struct btrfs_ioctl_search_args __user *uargs;
2180  	struct btrfs_ioctl_search_key sk;
2181  	struct inode *inode;
2182  	int ret;
2183  	size_t buf_size;
2184  
2185  	if (!capable(CAP_SYS_ADMIN))
2186  		return -EPERM;
2187  
2188  	uargs = (struct btrfs_ioctl_search_args __user *)argp;
2189  
2190  	if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
2191  		return -EFAULT;
2192  
2193  	buf_size = sizeof(uargs->buf);
2194  
2195  	inode = file_inode(file);
2196  	ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
2197  
2198  	/*
2199  	 * In the origin implementation an overflow is handled by returning a
2200  	 * search header with a len of zero, so reset ret.
2201  	 */
2202  	if (ret == -EOVERFLOW)
2203  		ret = 0;
2204  
2205  	if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
2206  		ret = -EFAULT;
2207  	return ret;
2208  }
2209  
2210  static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
2211  					       void __user *argp)
2212  {
2213  	struct btrfs_ioctl_search_args_v2 __user *uarg;
2214  	struct btrfs_ioctl_search_args_v2 args;
2215  	struct inode *inode;
2216  	int ret;
2217  	size_t buf_size;
2218  	const size_t buf_limit = SZ_16M;
2219  
2220  	if (!capable(CAP_SYS_ADMIN))
2221  		return -EPERM;
2222  
2223  	/* copy search header and buffer size */
2224  	uarg = (struct btrfs_ioctl_search_args_v2 __user *)argp;
2225  	if (copy_from_user(&args, uarg, sizeof(args)))
2226  		return -EFAULT;
2227  
2228  	buf_size = args.buf_size;
2229  
2230  	/* limit result size to 16MB */
2231  	if (buf_size > buf_limit)
2232  		buf_size = buf_limit;
2233  
2234  	inode = file_inode(file);
2235  	ret = search_ioctl(inode, &args.key, &buf_size,
2236  			   (char __user *)(&uarg->buf[0]));
2237  	if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
2238  		ret = -EFAULT;
2239  	else if (ret == -EOVERFLOW &&
2240  		copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
2241  		ret = -EFAULT;
2242  
2243  	return ret;
2244  }
2245  
2246  /*
2247   * Search INODE_REFs to identify path name of 'dirid' directory
2248   * in a 'tree_id' tree. and sets path name to 'name'.
2249   */
2250  static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2251  				u64 tree_id, u64 dirid, char *name)
2252  {
2253  	struct btrfs_root *root;
2254  	struct btrfs_key key;
2255  	char *ptr;
2256  	int ret = -1;
2257  	int slot;
2258  	int len;
2259  	int total_len = 0;
2260  	struct btrfs_inode_ref *iref;
2261  	struct extent_buffer *l;
2262  	struct btrfs_path *path;
2263  
2264  	if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2265  		name[0]='\0';
2266  		return 0;
2267  	}
2268  
2269  	path = btrfs_alloc_path();
2270  	if (!path)
2271  		return -ENOMEM;
2272  
2273  	ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX - 1];
2274  
2275  	root = btrfs_get_fs_root(info, tree_id, true);
2276  	if (IS_ERR(root)) {
2277  		ret = PTR_ERR(root);
2278  		root = NULL;
2279  		goto out;
2280  	}
2281  
2282  	key.objectid = dirid;
2283  	key.type = BTRFS_INODE_REF_KEY;
2284  	key.offset = (u64)-1;
2285  
2286  	while (1) {
2287  		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2288  		if (ret < 0)
2289  			goto out;
2290  		else if (ret > 0) {
2291  			ret = btrfs_previous_item(root, path, dirid,
2292  						  BTRFS_INODE_REF_KEY);
2293  			if (ret < 0)
2294  				goto out;
2295  			else if (ret > 0) {
2296  				ret = -ENOENT;
2297  				goto out;
2298  			}
2299  		}
2300  
2301  		l = path->nodes[0];
2302  		slot = path->slots[0];
2303  		btrfs_item_key_to_cpu(l, &key, slot);
2304  
2305  		iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2306  		len = btrfs_inode_ref_name_len(l, iref);
2307  		ptr -= len + 1;
2308  		total_len += len + 1;
2309  		if (ptr < name) {
2310  			ret = -ENAMETOOLONG;
2311  			goto out;
2312  		}
2313  
2314  		*(ptr + len) = '/';
2315  		read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2316  
2317  		if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2318  			break;
2319  
2320  		btrfs_release_path(path);
2321  		key.objectid = key.offset;
2322  		key.offset = (u64)-1;
2323  		dirid = key.objectid;
2324  	}
2325  	memmove(name, ptr, total_len);
2326  	name[total_len] = '\0';
2327  	ret = 0;
2328  out:
2329  	btrfs_put_root(root);
2330  	btrfs_free_path(path);
2331  	return ret;
2332  }
2333  
2334  static int btrfs_search_path_in_tree_user(struct inode *inode,
2335  				struct btrfs_ioctl_ino_lookup_user_args *args)
2336  {
2337  	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2338  	struct super_block *sb = inode->i_sb;
2339  	struct btrfs_key upper_limit = BTRFS_I(inode)->location;
2340  	u64 treeid = BTRFS_I(inode)->root->root_key.objectid;
2341  	u64 dirid = args->dirid;
2342  	unsigned long item_off;
2343  	unsigned long item_len;
2344  	struct btrfs_inode_ref *iref;
2345  	struct btrfs_root_ref *rref;
2346  	struct btrfs_root *root = NULL;
2347  	struct btrfs_path *path;
2348  	struct btrfs_key key, key2;
2349  	struct extent_buffer *leaf;
2350  	struct inode *temp_inode;
2351  	char *ptr;
2352  	int slot;
2353  	int len;
2354  	int total_len = 0;
2355  	int ret;
2356  
2357  	path = btrfs_alloc_path();
2358  	if (!path)
2359  		return -ENOMEM;
2360  
2361  	/*
2362  	 * If the bottom subvolume does not exist directly under upper_limit,
2363  	 * construct the path in from the bottom up.
2364  	 */
2365  	if (dirid != upper_limit.objectid) {
2366  		ptr = &args->path[BTRFS_INO_LOOKUP_USER_PATH_MAX - 1];
2367  
2368  		root = btrfs_get_fs_root(fs_info, treeid, true);
2369  		if (IS_ERR(root)) {
2370  			ret = PTR_ERR(root);
2371  			goto out;
2372  		}
2373  
2374  		key.objectid = dirid;
2375  		key.type = BTRFS_INODE_REF_KEY;
2376  		key.offset = (u64)-1;
2377  		while (1) {
2378  			ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2379  			if (ret < 0) {
2380  				goto out_put;
2381  			} else if (ret > 0) {
2382  				ret = btrfs_previous_item(root, path, dirid,
2383  							  BTRFS_INODE_REF_KEY);
2384  				if (ret < 0) {
2385  					goto out_put;
2386  				} else if (ret > 0) {
2387  					ret = -ENOENT;
2388  					goto out_put;
2389  				}
2390  			}
2391  
2392  			leaf = path->nodes[0];
2393  			slot = path->slots[0];
2394  			btrfs_item_key_to_cpu(leaf, &key, slot);
2395  
2396  			iref = btrfs_item_ptr(leaf, slot, struct btrfs_inode_ref);
2397  			len = btrfs_inode_ref_name_len(leaf, iref);
2398  			ptr -= len + 1;
2399  			total_len += len + 1;
2400  			if (ptr < args->path) {
2401  				ret = -ENAMETOOLONG;
2402  				goto out_put;
2403  			}
2404  
2405  			*(ptr + len) = '/';
2406  			read_extent_buffer(leaf, ptr,
2407  					(unsigned long)(iref + 1), len);
2408  
2409  			/* Check the read+exec permission of this directory */
2410  			ret = btrfs_previous_item(root, path, dirid,
2411  						  BTRFS_INODE_ITEM_KEY);
2412  			if (ret < 0) {
2413  				goto out_put;
2414  			} else if (ret > 0) {
2415  				ret = -ENOENT;
2416  				goto out_put;
2417  			}
2418  
2419  			leaf = path->nodes[0];
2420  			slot = path->slots[0];
2421  			btrfs_item_key_to_cpu(leaf, &key2, slot);
2422  			if (key2.objectid != dirid) {
2423  				ret = -ENOENT;
2424  				goto out_put;
2425  			}
2426  
2427  			temp_inode = btrfs_iget(sb, key2.objectid, root);
2428  			if (IS_ERR(temp_inode)) {
2429  				ret = PTR_ERR(temp_inode);
2430  				goto out_put;
2431  			}
2432  			ret = inode_permission(temp_inode, MAY_READ | MAY_EXEC);
2433  			iput(temp_inode);
2434  			if (ret) {
2435  				ret = -EACCES;
2436  				goto out_put;
2437  			}
2438  
2439  			if (key.offset == upper_limit.objectid)
2440  				break;
2441  			if (key.objectid == BTRFS_FIRST_FREE_OBJECTID) {
2442  				ret = -EACCES;
2443  				goto out_put;
2444  			}
2445  
2446  			btrfs_release_path(path);
2447  			key.objectid = key.offset;
2448  			key.offset = (u64)-1;
2449  			dirid = key.objectid;
2450  		}
2451  
2452  		memmove(args->path, ptr, total_len);
2453  		args->path[total_len] = '\0';
2454  		btrfs_put_root(root);
2455  		root = NULL;
2456  		btrfs_release_path(path);
2457  	}
2458  
2459  	/* Get the bottom subvolume's name from ROOT_REF */
2460  	key.objectid = treeid;
2461  	key.type = BTRFS_ROOT_REF_KEY;
2462  	key.offset = args->treeid;
2463  	ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2464  	if (ret < 0) {
2465  		goto out;
2466  	} else if (ret > 0) {
2467  		ret = -ENOENT;
2468  		goto out;
2469  	}
2470  
2471  	leaf = path->nodes[0];
2472  	slot = path->slots[0];
2473  	btrfs_item_key_to_cpu(leaf, &key, slot);
2474  
2475  	item_off = btrfs_item_ptr_offset(leaf, slot);
2476  	item_len = btrfs_item_size_nr(leaf, slot);
2477  	/* Check if dirid in ROOT_REF corresponds to passed dirid */
2478  	rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2479  	if (args->dirid != btrfs_root_ref_dirid(leaf, rref)) {
2480  		ret = -EINVAL;
2481  		goto out;
2482  	}
2483  
2484  	/* Copy subvolume's name */
2485  	item_off += sizeof(struct btrfs_root_ref);
2486  	item_len -= sizeof(struct btrfs_root_ref);
2487  	read_extent_buffer(leaf, args->name, item_off, item_len);
2488  	args->name[item_len] = 0;
2489  
2490  out_put:
2491  	btrfs_put_root(root);
2492  out:
2493  	btrfs_free_path(path);
2494  	return ret;
2495  }
2496  
2497  static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2498  					   void __user *argp)
2499  {
2500  	struct btrfs_ioctl_ino_lookup_args *args;
2501  	struct inode *inode;
2502  	int ret = 0;
2503  
2504  	args = memdup_user(argp, sizeof(*args));
2505  	if (IS_ERR(args))
2506  		return PTR_ERR(args);
2507  
2508  	inode = file_inode(file);
2509  
2510  	/*
2511  	 * Unprivileged query to obtain the containing subvolume root id. The
2512  	 * path is reset so it's consistent with btrfs_search_path_in_tree.
2513  	 */
2514  	if (args->treeid == 0)
2515  		args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2516  
2517  	if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2518  		args->name[0] = 0;
2519  		goto out;
2520  	}
2521  
2522  	if (!capable(CAP_SYS_ADMIN)) {
2523  		ret = -EPERM;
2524  		goto out;
2525  	}
2526  
2527  	ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2528  					args->treeid, args->objectid,
2529  					args->name);
2530  
2531  out:
2532  	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2533  		ret = -EFAULT;
2534  
2535  	kfree(args);
2536  	return ret;
2537  }
2538  
2539  /*
2540   * Version of ino_lookup ioctl (unprivileged)
2541   *
2542   * The main differences from ino_lookup ioctl are:
2543   *
2544   *   1. Read + Exec permission will be checked using inode_permission() during
2545   *      path construction. -EACCES will be returned in case of failure.
2546   *   2. Path construction will be stopped at the inode number which corresponds
2547   *      to the fd with which this ioctl is called. If constructed path does not
2548   *      exist under fd's inode, -EACCES will be returned.
2549   *   3. The name of bottom subvolume is also searched and filled.
2550   */
2551  static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp)
2552  {
2553  	struct btrfs_ioctl_ino_lookup_user_args *args;
2554  	struct inode *inode;
2555  	int ret;
2556  
2557  	args = memdup_user(argp, sizeof(*args));
2558  	if (IS_ERR(args))
2559  		return PTR_ERR(args);
2560  
2561  	inode = file_inode(file);
2562  
2563  	if (args->dirid == BTRFS_FIRST_FREE_OBJECTID &&
2564  	    BTRFS_I(inode)->location.objectid != BTRFS_FIRST_FREE_OBJECTID) {
2565  		/*
2566  		 * The subvolume does not exist under fd with which this is
2567  		 * called
2568  		 */
2569  		kfree(args);
2570  		return -EACCES;
2571  	}
2572  
2573  	ret = btrfs_search_path_in_tree_user(inode, args);
2574  
2575  	if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2576  		ret = -EFAULT;
2577  
2578  	kfree(args);
2579  	return ret;
2580  }
2581  
2582  /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */
2583  static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
2584  {
2585  	struct btrfs_ioctl_get_subvol_info_args *subvol_info;
2586  	struct btrfs_fs_info *fs_info;
2587  	struct btrfs_root *root;
2588  	struct btrfs_path *path;
2589  	struct btrfs_key key;
2590  	struct btrfs_root_item *root_item;
2591  	struct btrfs_root_ref *rref;
2592  	struct extent_buffer *leaf;
2593  	unsigned long item_off;
2594  	unsigned long item_len;
2595  	struct inode *inode;
2596  	int slot;
2597  	int ret = 0;
2598  
2599  	path = btrfs_alloc_path();
2600  	if (!path)
2601  		return -ENOMEM;
2602  
2603  	subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL);
2604  	if (!subvol_info) {
2605  		btrfs_free_path(path);
2606  		return -ENOMEM;
2607  	}
2608  
2609  	inode = file_inode(file);
2610  	fs_info = BTRFS_I(inode)->root->fs_info;
2611  
2612  	/* Get root_item of inode's subvolume */
2613  	key.objectid = BTRFS_I(inode)->root->root_key.objectid;
2614  	root = btrfs_get_fs_root(fs_info, key.objectid, true);
2615  	if (IS_ERR(root)) {
2616  		ret = PTR_ERR(root);
2617  		goto out_free;
2618  	}
2619  	root_item = &root->root_item;
2620  
2621  	subvol_info->treeid = key.objectid;
2622  
2623  	subvol_info->generation = btrfs_root_generation(root_item);
2624  	subvol_info->flags = btrfs_root_flags(root_item);
2625  
2626  	memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE);
2627  	memcpy(subvol_info->parent_uuid, root_item->parent_uuid,
2628  						    BTRFS_UUID_SIZE);
2629  	memcpy(subvol_info->received_uuid, root_item->received_uuid,
2630  						    BTRFS_UUID_SIZE);
2631  
2632  	subvol_info->ctransid = btrfs_root_ctransid(root_item);
2633  	subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
2634  	subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
2635  
2636  	subvol_info->otransid = btrfs_root_otransid(root_item);
2637  	subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
2638  	subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
2639  
2640  	subvol_info->stransid = btrfs_root_stransid(root_item);
2641  	subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
2642  	subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
2643  
2644  	subvol_info->rtransid = btrfs_root_rtransid(root_item);
2645  	subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
2646  	subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
2647  
2648  	if (key.objectid != BTRFS_FS_TREE_OBJECTID) {
2649  		/* Search root tree for ROOT_BACKREF of this subvolume */
2650  		key.type = BTRFS_ROOT_BACKREF_KEY;
2651  		key.offset = 0;
2652  		ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2653  		if (ret < 0) {
2654  			goto out;
2655  		} else if (path->slots[0] >=
2656  			   btrfs_header_nritems(path->nodes[0])) {
2657  			ret = btrfs_next_leaf(fs_info->tree_root, path);
2658  			if (ret < 0) {
2659  				goto out;
2660  			} else if (ret > 0) {
2661  				ret = -EUCLEAN;
2662  				goto out;
2663  			}
2664  		}
2665  
2666  		leaf = path->nodes[0];
2667  		slot = path->slots[0];
2668  		btrfs_item_key_to_cpu(leaf, &key, slot);
2669  		if (key.objectid == subvol_info->treeid &&
2670  		    key.type == BTRFS_ROOT_BACKREF_KEY) {
2671  			subvol_info->parent_id = key.offset;
2672  
2673  			rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2674  			subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref);
2675  
2676  			item_off = btrfs_item_ptr_offset(leaf, slot)
2677  					+ sizeof(struct btrfs_root_ref);
2678  			item_len = btrfs_item_size_nr(leaf, slot)
2679  					- sizeof(struct btrfs_root_ref);
2680  			read_extent_buffer(leaf, subvol_info->name,
2681  					   item_off, item_len);
2682  		} else {
2683  			ret = -ENOENT;
2684  			goto out;
2685  		}
2686  	}
2687  
2688  	if (copy_to_user(argp, subvol_info, sizeof(*subvol_info)))
2689  		ret = -EFAULT;
2690  
2691  out:
2692  	btrfs_put_root(root);
2693  out_free:
2694  	btrfs_free_path(path);
2695  	kzfree(subvol_info);
2696  	return ret;
2697  }
2698  
2699  /*
2700   * Return ROOT_REF information of the subvolume containing this inode
2701   * except the subvolume name.
2702   */
2703  static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
2704  {
2705  	struct btrfs_ioctl_get_subvol_rootref_args *rootrefs;
2706  	struct btrfs_root_ref *rref;
2707  	struct btrfs_root *root;
2708  	struct btrfs_path *path;
2709  	struct btrfs_key key;
2710  	struct extent_buffer *leaf;
2711  	struct inode *inode;
2712  	u64 objectid;
2713  	int slot;
2714  	int ret;
2715  	u8 found;
2716  
2717  	path = btrfs_alloc_path();
2718  	if (!path)
2719  		return -ENOMEM;
2720  
2721  	rootrefs = memdup_user(argp, sizeof(*rootrefs));
2722  	if (IS_ERR(rootrefs)) {
2723  		btrfs_free_path(path);
2724  		return PTR_ERR(rootrefs);
2725  	}
2726  
2727  	inode = file_inode(file);
2728  	root = BTRFS_I(inode)->root->fs_info->tree_root;
2729  	objectid = BTRFS_I(inode)->root->root_key.objectid;
2730  
2731  	key.objectid = objectid;
2732  	key.type = BTRFS_ROOT_REF_KEY;
2733  	key.offset = rootrefs->min_treeid;
2734  	found = 0;
2735  
2736  	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2737  	if (ret < 0) {
2738  		goto out;
2739  	} else if (path->slots[0] >=
2740  		   btrfs_header_nritems(path->nodes[0])) {
2741  		ret = btrfs_next_leaf(root, path);
2742  		if (ret < 0) {
2743  			goto out;
2744  		} else if (ret > 0) {
2745  			ret = -EUCLEAN;
2746  			goto out;
2747  		}
2748  	}
2749  	while (1) {
2750  		leaf = path->nodes[0];
2751  		slot = path->slots[0];
2752  
2753  		btrfs_item_key_to_cpu(leaf, &key, slot);
2754  		if (key.objectid != objectid || key.type != BTRFS_ROOT_REF_KEY) {
2755  			ret = 0;
2756  			goto out;
2757  		}
2758  
2759  		if (found == BTRFS_MAX_ROOTREF_BUFFER_NUM) {
2760  			ret = -EOVERFLOW;
2761  			goto out;
2762  		}
2763  
2764  		rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2765  		rootrefs->rootref[found].treeid = key.offset;
2766  		rootrefs->rootref[found].dirid =
2767  				  btrfs_root_ref_dirid(leaf, rref);
2768  		found++;
2769  
2770  		ret = btrfs_next_item(root, path);
2771  		if (ret < 0) {
2772  			goto out;
2773  		} else if (ret > 0) {
2774  			ret = -EUCLEAN;
2775  			goto out;
2776  		}
2777  	}
2778  
2779  out:
2780  	if (!ret || ret == -EOVERFLOW) {
2781  		rootrefs->num_items = found;
2782  		/* update min_treeid for next search */
2783  		if (found)
2784  			rootrefs->min_treeid =
2785  				rootrefs->rootref[found - 1].treeid + 1;
2786  		if (copy_to_user(argp, rootrefs, sizeof(*rootrefs)))
2787  			ret = -EFAULT;
2788  	}
2789  
2790  	kfree(rootrefs);
2791  	btrfs_free_path(path);
2792  
2793  	return ret;
2794  }
2795  
2796  static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2797  					     void __user *arg,
2798  					     bool destroy_v2)
2799  {
2800  	struct dentry *parent = file->f_path.dentry;
2801  	struct btrfs_fs_info *fs_info = btrfs_sb(parent->d_sb);
2802  	struct dentry *dentry;
2803  	struct inode *dir = d_inode(parent);
2804  	struct inode *inode;
2805  	struct btrfs_root *root = BTRFS_I(dir)->root;
2806  	struct btrfs_root *dest = NULL;
2807  	struct btrfs_ioctl_vol_args *vol_args = NULL;
2808  	struct btrfs_ioctl_vol_args_v2 *vol_args2 = NULL;
2809  	char *subvol_name, *subvol_name_ptr = NULL;
2810  	int subvol_namelen;
2811  	int err = 0;
2812  	bool destroy_parent = false;
2813  
2814  	if (destroy_v2) {
2815  		vol_args2 = memdup_user(arg, sizeof(*vol_args2));
2816  		if (IS_ERR(vol_args2))
2817  			return PTR_ERR(vol_args2);
2818  
2819  		if (vol_args2->flags & ~BTRFS_SUBVOL_DELETE_ARGS_MASK) {
2820  			err = -EOPNOTSUPP;
2821  			goto out;
2822  		}
2823  
2824  		/*
2825  		 * If SPEC_BY_ID is not set, we are looking for the subvolume by
2826  		 * name, same as v1 currently does.
2827  		 */
2828  		if (!(vol_args2->flags & BTRFS_SUBVOL_SPEC_BY_ID)) {
2829  			vol_args2->name[BTRFS_SUBVOL_NAME_MAX] = 0;
2830  			subvol_name = vol_args2->name;
2831  
2832  			err = mnt_want_write_file(file);
2833  			if (err)
2834  				goto out;
2835  		} else {
2836  			if (vol_args2->subvolid < BTRFS_FIRST_FREE_OBJECTID) {
2837  				err = -EINVAL;
2838  				goto out;
2839  			}
2840  
2841  			err = mnt_want_write_file(file);
2842  			if (err)
2843  				goto out;
2844  
2845  			dentry = btrfs_get_dentry(fs_info->sb,
2846  					BTRFS_FIRST_FREE_OBJECTID,
2847  					vol_args2->subvolid, 0, 0);
2848  			if (IS_ERR(dentry)) {
2849  				err = PTR_ERR(dentry);
2850  				goto out_drop_write;
2851  			}
2852  
2853  			/*
2854  			 * Change the default parent since the subvolume being
2855  			 * deleted can be outside of the current mount point.
2856  			 */
2857  			parent = btrfs_get_parent(dentry);
2858  
2859  			/*
2860  			 * At this point dentry->d_name can point to '/' if the
2861  			 * subvolume we want to destroy is outsite of the
2862  			 * current mount point, so we need to release the
2863  			 * current dentry and execute the lookup to return a new
2864  			 * one with ->d_name pointing to the
2865  			 * <mount point>/subvol_name.
2866  			 */
2867  			dput(dentry);
2868  			if (IS_ERR(parent)) {
2869  				err = PTR_ERR(parent);
2870  				goto out_drop_write;
2871  			}
2872  			dir = d_inode(parent);
2873  
2874  			/*
2875  			 * If v2 was used with SPEC_BY_ID, a new parent was
2876  			 * allocated since the subvolume can be outside of the
2877  			 * current mount point. Later on we need to release this
2878  			 * new parent dentry.
2879  			 */
2880  			destroy_parent = true;
2881  
2882  			subvol_name_ptr = btrfs_get_subvol_name_from_objectid(
2883  						fs_info, vol_args2->subvolid);
2884  			if (IS_ERR(subvol_name_ptr)) {
2885  				err = PTR_ERR(subvol_name_ptr);
2886  				goto free_parent;
2887  			}
2888  			/* subvol_name_ptr is already NULL termined */
2889  			subvol_name = (char *)kbasename(subvol_name_ptr);
2890  		}
2891  	} else {
2892  		vol_args = memdup_user(arg, sizeof(*vol_args));
2893  		if (IS_ERR(vol_args))
2894  			return PTR_ERR(vol_args);
2895  
2896  		vol_args->name[BTRFS_PATH_NAME_MAX] = 0;
2897  		subvol_name = vol_args->name;
2898  
2899  		err = mnt_want_write_file(file);
2900  		if (err)
2901  			goto out;
2902  	}
2903  
2904  	subvol_namelen = strlen(subvol_name);
2905  
2906  	if (strchr(subvol_name, '/') ||
2907  	    strncmp(subvol_name, "..", subvol_namelen) == 0) {
2908  		err = -EINVAL;
2909  		goto free_subvol_name;
2910  	}
2911  
2912  	if (!S_ISDIR(dir->i_mode)) {
2913  		err = -ENOTDIR;
2914  		goto free_subvol_name;
2915  	}
2916  
2917  	err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
2918  	if (err == -EINTR)
2919  		goto free_subvol_name;
2920  	dentry = lookup_one_len(subvol_name, parent, subvol_namelen);
2921  	if (IS_ERR(dentry)) {
2922  		err = PTR_ERR(dentry);
2923  		goto out_unlock_dir;
2924  	}
2925  
2926  	if (d_really_is_negative(dentry)) {
2927  		err = -ENOENT;
2928  		goto out_dput;
2929  	}
2930  
2931  	inode = d_inode(dentry);
2932  	dest = BTRFS_I(inode)->root;
2933  	if (!capable(CAP_SYS_ADMIN)) {
2934  		/*
2935  		 * Regular user.  Only allow this with a special mount
2936  		 * option, when the user has write+exec access to the
2937  		 * subvol root, and when rmdir(2) would have been
2938  		 * allowed.
2939  		 *
2940  		 * Note that this is _not_ check that the subvol is
2941  		 * empty or doesn't contain data that we wouldn't
2942  		 * otherwise be able to delete.
2943  		 *
2944  		 * Users who want to delete empty subvols should try
2945  		 * rmdir(2).
2946  		 */
2947  		err = -EPERM;
2948  		if (!btrfs_test_opt(fs_info, USER_SUBVOL_RM_ALLOWED))
2949  			goto out_dput;
2950  
2951  		/*
2952  		 * Do not allow deletion if the parent dir is the same
2953  		 * as the dir to be deleted.  That means the ioctl
2954  		 * must be called on the dentry referencing the root
2955  		 * of the subvol, not a random directory contained
2956  		 * within it.
2957  		 */
2958  		err = -EINVAL;
2959  		if (root == dest)
2960  			goto out_dput;
2961  
2962  		err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2963  		if (err)
2964  			goto out_dput;
2965  	}
2966  
2967  	/* check if subvolume may be deleted by a user */
2968  	err = btrfs_may_delete(dir, dentry, 1);
2969  	if (err)
2970  		goto out_dput;
2971  
2972  	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2973  		err = -EINVAL;
2974  		goto out_dput;
2975  	}
2976  
2977  	inode_lock(inode);
2978  	err = btrfs_delete_subvolume(dir, dentry);
2979  	inode_unlock(inode);
2980  	if (!err) {
2981  		fsnotify_rmdir(dir, dentry);
2982  		d_delete(dentry);
2983  	}
2984  
2985  out_dput:
2986  	dput(dentry);
2987  out_unlock_dir:
2988  	inode_unlock(dir);
2989  free_subvol_name:
2990  	kfree(subvol_name_ptr);
2991  free_parent:
2992  	if (destroy_parent)
2993  		dput(parent);
2994  out_drop_write:
2995  	mnt_drop_write_file(file);
2996  out:
2997  	kfree(vol_args2);
2998  	kfree(vol_args);
2999  	return err;
3000  }
3001  
3002  static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
3003  {
3004  	struct inode *inode = file_inode(file);
3005  	struct btrfs_root *root = BTRFS_I(inode)->root;
3006  	struct btrfs_ioctl_defrag_range_args *range;
3007  	int ret;
3008  
3009  	ret = mnt_want_write_file(file);
3010  	if (ret)
3011  		return ret;
3012  
3013  	if (btrfs_root_readonly(root)) {
3014  		ret = -EROFS;
3015  		goto out;
3016  	}
3017  
3018  	switch (inode->i_mode & S_IFMT) {
3019  	case S_IFDIR:
3020  		if (!capable(CAP_SYS_ADMIN)) {
3021  			ret = -EPERM;
3022  			goto out;
3023  		}
3024  		ret = btrfs_defrag_root(root);
3025  		break;
3026  	case S_IFREG:
3027  		/*
3028  		 * Note that this does not check the file descriptor for write
3029  		 * access. This prevents defragmenting executables that are
3030  		 * running and allows defrag on files open in read-only mode.
3031  		 */
3032  		if (!capable(CAP_SYS_ADMIN) &&
3033  		    inode_permission(inode, MAY_WRITE)) {
3034  			ret = -EPERM;
3035  			goto out;
3036  		}
3037  
3038  		range = kzalloc(sizeof(*range), GFP_KERNEL);
3039  		if (!range) {
3040  			ret = -ENOMEM;
3041  			goto out;
3042  		}
3043  
3044  		if (argp) {
3045  			if (copy_from_user(range, argp,
3046  					   sizeof(*range))) {
3047  				ret = -EFAULT;
3048  				kfree(range);
3049  				goto out;
3050  			}
3051  			/* compression requires us to start the IO */
3052  			if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
3053  				range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
3054  				range->extent_thresh = (u32)-1;
3055  			}
3056  		} else {
3057  			/* the rest are all set to zero by kzalloc */
3058  			range->len = (u64)-1;
3059  		}
3060  		ret = btrfs_defrag_file(file_inode(file), file,
3061  					range, BTRFS_OLDEST_GENERATION, 0);
3062  		if (ret > 0)
3063  			ret = 0;
3064  		kfree(range);
3065  		break;
3066  	default:
3067  		ret = -EINVAL;
3068  	}
3069  out:
3070  	mnt_drop_write_file(file);
3071  	return ret;
3072  }
3073  
3074  static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
3075  {
3076  	struct btrfs_ioctl_vol_args *vol_args;
3077  	int ret;
3078  
3079  	if (!capable(CAP_SYS_ADMIN))
3080  		return -EPERM;
3081  
3082  	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags))
3083  		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3084  
3085  	vol_args = memdup_user(arg, sizeof(*vol_args));
3086  	if (IS_ERR(vol_args)) {
3087  		ret = PTR_ERR(vol_args);
3088  		goto out;
3089  	}
3090  
3091  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
3092  	ret = btrfs_init_new_device(fs_info, vol_args->name);
3093  
3094  	if (!ret)
3095  		btrfs_info(fs_info, "disk added %s", vol_args->name);
3096  
3097  	kfree(vol_args);
3098  out:
3099  	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3100  	return ret;
3101  }
3102  
3103  static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
3104  {
3105  	struct inode *inode = file_inode(file);
3106  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3107  	struct btrfs_ioctl_vol_args_v2 *vol_args;
3108  	int ret;
3109  
3110  	if (!capable(CAP_SYS_ADMIN))
3111  		return -EPERM;
3112  
3113  	ret = mnt_want_write_file(file);
3114  	if (ret)
3115  		return ret;
3116  
3117  	vol_args = memdup_user(arg, sizeof(*vol_args));
3118  	if (IS_ERR(vol_args)) {
3119  		ret = PTR_ERR(vol_args);
3120  		goto err_drop;
3121  	}
3122  
3123  	if (vol_args->flags & ~BTRFS_DEVICE_REMOVE_ARGS_MASK) {
3124  		ret = -EOPNOTSUPP;
3125  		goto out;
3126  	}
3127  
3128  	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3129  		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3130  		goto out;
3131  	}
3132  
3133  	if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
3134  		ret = btrfs_rm_device(fs_info, NULL, vol_args->devid);
3135  	} else {
3136  		vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
3137  		ret = btrfs_rm_device(fs_info, vol_args->name, 0);
3138  	}
3139  	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3140  
3141  	if (!ret) {
3142  		if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
3143  			btrfs_info(fs_info, "device deleted: id %llu",
3144  					vol_args->devid);
3145  		else
3146  			btrfs_info(fs_info, "device deleted: %s",
3147  					vol_args->name);
3148  	}
3149  out:
3150  	kfree(vol_args);
3151  err_drop:
3152  	mnt_drop_write_file(file);
3153  	return ret;
3154  }
3155  
3156  static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
3157  {
3158  	struct inode *inode = file_inode(file);
3159  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3160  	struct btrfs_ioctl_vol_args *vol_args;
3161  	int ret;
3162  
3163  	if (!capable(CAP_SYS_ADMIN))
3164  		return -EPERM;
3165  
3166  	ret = mnt_want_write_file(file);
3167  	if (ret)
3168  		return ret;
3169  
3170  	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3171  		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3172  		goto out_drop_write;
3173  	}
3174  
3175  	vol_args = memdup_user(arg, sizeof(*vol_args));
3176  	if (IS_ERR(vol_args)) {
3177  		ret = PTR_ERR(vol_args);
3178  		goto out;
3179  	}
3180  
3181  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
3182  	ret = btrfs_rm_device(fs_info, vol_args->name, 0);
3183  
3184  	if (!ret)
3185  		btrfs_info(fs_info, "disk deleted %s", vol_args->name);
3186  	kfree(vol_args);
3187  out:
3188  	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3189  out_drop_write:
3190  	mnt_drop_write_file(file);
3191  
3192  	return ret;
3193  }
3194  
3195  static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info,
3196  				void __user *arg)
3197  {
3198  	struct btrfs_ioctl_fs_info_args *fi_args;
3199  	struct btrfs_device *device;
3200  	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
3201  	int ret = 0;
3202  
3203  	fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
3204  	if (!fi_args)
3205  		return -ENOMEM;
3206  
3207  	rcu_read_lock();
3208  	fi_args->num_devices = fs_devices->num_devices;
3209  
3210  	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
3211  		if (device->devid > fi_args->max_id)
3212  			fi_args->max_id = device->devid;
3213  	}
3214  	rcu_read_unlock();
3215  
3216  	memcpy(&fi_args->fsid, fs_devices->fsid, sizeof(fi_args->fsid));
3217  	fi_args->nodesize = fs_info->nodesize;
3218  	fi_args->sectorsize = fs_info->sectorsize;
3219  	fi_args->clone_alignment = fs_info->sectorsize;
3220  
3221  	if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
3222  		ret = -EFAULT;
3223  
3224  	kfree(fi_args);
3225  	return ret;
3226  }
3227  
3228  static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
3229  				 void __user *arg)
3230  {
3231  	struct btrfs_ioctl_dev_info_args *di_args;
3232  	struct btrfs_device *dev;
3233  	int ret = 0;
3234  	char *s_uuid = NULL;
3235  
3236  	di_args = memdup_user(arg, sizeof(*di_args));
3237  	if (IS_ERR(di_args))
3238  		return PTR_ERR(di_args);
3239  
3240  	if (!btrfs_is_empty_uuid(di_args->uuid))
3241  		s_uuid = di_args->uuid;
3242  
3243  	rcu_read_lock();
3244  	dev = btrfs_find_device(fs_info->fs_devices, di_args->devid, s_uuid,
3245  				NULL, true);
3246  
3247  	if (!dev) {
3248  		ret = -ENODEV;
3249  		goto out;
3250  	}
3251  
3252  	di_args->devid = dev->devid;
3253  	di_args->bytes_used = btrfs_device_get_bytes_used(dev);
3254  	di_args->total_bytes = btrfs_device_get_total_bytes(dev);
3255  	memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
3256  	if (dev->name) {
3257  		strncpy(di_args->path, rcu_str_deref(dev->name),
3258  				sizeof(di_args->path) - 1);
3259  		di_args->path[sizeof(di_args->path) - 1] = 0;
3260  	} else {
3261  		di_args->path[0] = '\0';
3262  	}
3263  
3264  out:
3265  	rcu_read_unlock();
3266  	if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
3267  		ret = -EFAULT;
3268  
3269  	kfree(di_args);
3270  	return ret;
3271  }
3272  
3273  static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
3274  {
3275  	struct inode *inode = file_inode(file);
3276  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3277  	struct btrfs_root *root = BTRFS_I(inode)->root;
3278  	struct btrfs_root *new_root;
3279  	struct btrfs_dir_item *di;
3280  	struct btrfs_trans_handle *trans;
3281  	struct btrfs_path *path = NULL;
3282  	struct btrfs_disk_key disk_key;
3283  	u64 objectid = 0;
3284  	u64 dir_id;
3285  	int ret;
3286  
3287  	if (!capable(CAP_SYS_ADMIN))
3288  		return -EPERM;
3289  
3290  	ret = mnt_want_write_file(file);
3291  	if (ret)
3292  		return ret;
3293  
3294  	if (copy_from_user(&objectid, argp, sizeof(objectid))) {
3295  		ret = -EFAULT;
3296  		goto out;
3297  	}
3298  
3299  	if (!objectid)
3300  		objectid = BTRFS_FS_TREE_OBJECTID;
3301  
3302  	new_root = btrfs_get_fs_root(fs_info, objectid, true);
3303  	if (IS_ERR(new_root)) {
3304  		ret = PTR_ERR(new_root);
3305  		goto out;
3306  	}
3307  	if (!is_fstree(new_root->root_key.objectid)) {
3308  		ret = -ENOENT;
3309  		goto out_free;
3310  	}
3311  
3312  	path = btrfs_alloc_path();
3313  	if (!path) {
3314  		ret = -ENOMEM;
3315  		goto out_free;
3316  	}
3317  	path->leave_spinning = 1;
3318  
3319  	trans = btrfs_start_transaction(root, 1);
3320  	if (IS_ERR(trans)) {
3321  		ret = PTR_ERR(trans);
3322  		goto out_free;
3323  	}
3324  
3325  	dir_id = btrfs_super_root_dir(fs_info->super_copy);
3326  	di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
3327  				   dir_id, "default", 7, 1);
3328  	if (IS_ERR_OR_NULL(di)) {
3329  		btrfs_release_path(path);
3330  		btrfs_end_transaction(trans);
3331  		btrfs_err(fs_info,
3332  			  "Umm, you don't have the default diritem, this isn't going to work");
3333  		ret = -ENOENT;
3334  		goto out_free;
3335  	}
3336  
3337  	btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
3338  	btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
3339  	btrfs_mark_buffer_dirty(path->nodes[0]);
3340  	btrfs_release_path(path);
3341  
3342  	btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
3343  	btrfs_end_transaction(trans);
3344  out_free:
3345  	btrfs_put_root(new_root);
3346  	btrfs_free_path(path);
3347  out:
3348  	mnt_drop_write_file(file);
3349  	return ret;
3350  }
3351  
3352  static void get_block_group_info(struct list_head *groups_list,
3353  				 struct btrfs_ioctl_space_info *space)
3354  {
3355  	struct btrfs_block_group *block_group;
3356  
3357  	space->total_bytes = 0;
3358  	space->used_bytes = 0;
3359  	space->flags = 0;
3360  	list_for_each_entry(block_group, groups_list, list) {
3361  		space->flags = block_group->flags;
3362  		space->total_bytes += block_group->length;
3363  		space->used_bytes += block_group->used;
3364  	}
3365  }
3366  
3367  static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info,
3368  				   void __user *arg)
3369  {
3370  	struct btrfs_ioctl_space_args space_args;
3371  	struct btrfs_ioctl_space_info space;
3372  	struct btrfs_ioctl_space_info *dest;
3373  	struct btrfs_ioctl_space_info *dest_orig;
3374  	struct btrfs_ioctl_space_info __user *user_dest;
3375  	struct btrfs_space_info *info;
3376  	static const u64 types[] = {
3377  		BTRFS_BLOCK_GROUP_DATA,
3378  		BTRFS_BLOCK_GROUP_SYSTEM,
3379  		BTRFS_BLOCK_GROUP_METADATA,
3380  		BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA
3381  	};
3382  	int num_types = 4;
3383  	int alloc_size;
3384  	int ret = 0;
3385  	u64 slot_count = 0;
3386  	int i, c;
3387  
3388  	if (copy_from_user(&space_args,
3389  			   (struct btrfs_ioctl_space_args __user *)arg,
3390  			   sizeof(space_args)))
3391  		return -EFAULT;
3392  
3393  	for (i = 0; i < num_types; i++) {
3394  		struct btrfs_space_info *tmp;
3395  
3396  		info = NULL;
3397  		rcu_read_lock();
3398  		list_for_each_entry_rcu(tmp, &fs_info->space_info,
3399  					list) {
3400  			if (tmp->flags == types[i]) {
3401  				info = tmp;
3402  				break;
3403  			}
3404  		}
3405  		rcu_read_unlock();
3406  
3407  		if (!info)
3408  			continue;
3409  
3410  		down_read(&info->groups_sem);
3411  		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3412  			if (!list_empty(&info->block_groups[c]))
3413  				slot_count++;
3414  		}
3415  		up_read(&info->groups_sem);
3416  	}
3417  
3418  	/*
3419  	 * Global block reserve, exported as a space_info
3420  	 */
3421  	slot_count++;
3422  
3423  	/* space_slots == 0 means they are asking for a count */
3424  	if (space_args.space_slots == 0) {
3425  		space_args.total_spaces = slot_count;
3426  		goto out;
3427  	}
3428  
3429  	slot_count = min_t(u64, space_args.space_slots, slot_count);
3430  
3431  	alloc_size = sizeof(*dest) * slot_count;
3432  
3433  	/* we generally have at most 6 or so space infos, one for each raid
3434  	 * level.  So, a whole page should be more than enough for everyone
3435  	 */
3436  	if (alloc_size > PAGE_SIZE)
3437  		return -ENOMEM;
3438  
3439  	space_args.total_spaces = 0;
3440  	dest = kmalloc(alloc_size, GFP_KERNEL);
3441  	if (!dest)
3442  		return -ENOMEM;
3443  	dest_orig = dest;
3444  
3445  	/* now we have a buffer to copy into */
3446  	for (i = 0; i < num_types; i++) {
3447  		struct btrfs_space_info *tmp;
3448  
3449  		if (!slot_count)
3450  			break;
3451  
3452  		info = NULL;
3453  		rcu_read_lock();
3454  		list_for_each_entry_rcu(tmp, &fs_info->space_info,
3455  					list) {
3456  			if (tmp->flags == types[i]) {
3457  				info = tmp;
3458  				break;
3459  			}
3460  		}
3461  		rcu_read_unlock();
3462  
3463  		if (!info)
3464  			continue;
3465  		down_read(&info->groups_sem);
3466  		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3467  			if (!list_empty(&info->block_groups[c])) {
3468  				get_block_group_info(&info->block_groups[c],
3469  						     &space);
3470  				memcpy(dest, &space, sizeof(space));
3471  				dest++;
3472  				space_args.total_spaces++;
3473  				slot_count--;
3474  			}
3475  			if (!slot_count)
3476  				break;
3477  		}
3478  		up_read(&info->groups_sem);
3479  	}
3480  
3481  	/*
3482  	 * Add global block reserve
3483  	 */
3484  	if (slot_count) {
3485  		struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3486  
3487  		spin_lock(&block_rsv->lock);
3488  		space.total_bytes = block_rsv->size;
3489  		space.used_bytes = block_rsv->size - block_rsv->reserved;
3490  		spin_unlock(&block_rsv->lock);
3491  		space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
3492  		memcpy(dest, &space, sizeof(space));
3493  		space_args.total_spaces++;
3494  	}
3495  
3496  	user_dest = (struct btrfs_ioctl_space_info __user *)
3497  		(arg + sizeof(struct btrfs_ioctl_space_args));
3498  
3499  	if (copy_to_user(user_dest, dest_orig, alloc_size))
3500  		ret = -EFAULT;
3501  
3502  	kfree(dest_orig);
3503  out:
3504  	if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
3505  		ret = -EFAULT;
3506  
3507  	return ret;
3508  }
3509  
3510  static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
3511  					    void __user *argp)
3512  {
3513  	struct btrfs_trans_handle *trans;
3514  	u64 transid;
3515  	int ret;
3516  
3517  	trans = btrfs_attach_transaction_barrier(root);
3518  	if (IS_ERR(trans)) {
3519  		if (PTR_ERR(trans) != -ENOENT)
3520  			return PTR_ERR(trans);
3521  
3522  		/* No running transaction, don't bother */
3523  		transid = root->fs_info->last_trans_committed;
3524  		goto out;
3525  	}
3526  	transid = trans->transid;
3527  	ret = btrfs_commit_transaction_async(trans, 0);
3528  	if (ret) {
3529  		btrfs_end_transaction(trans);
3530  		return ret;
3531  	}
3532  out:
3533  	if (argp)
3534  		if (copy_to_user(argp, &transid, sizeof(transid)))
3535  			return -EFAULT;
3536  	return 0;
3537  }
3538  
3539  static noinline long btrfs_ioctl_wait_sync(struct btrfs_fs_info *fs_info,
3540  					   void __user *argp)
3541  {
3542  	u64 transid;
3543  
3544  	if (argp) {
3545  		if (copy_from_user(&transid, argp, sizeof(transid)))
3546  			return -EFAULT;
3547  	} else {
3548  		transid = 0;  /* current trans */
3549  	}
3550  	return btrfs_wait_for_commit(fs_info, transid);
3551  }
3552  
3553  static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
3554  {
3555  	struct btrfs_fs_info *fs_info = btrfs_sb(file_inode(file)->i_sb);
3556  	struct btrfs_ioctl_scrub_args *sa;
3557  	int ret;
3558  
3559  	if (!capable(CAP_SYS_ADMIN))
3560  		return -EPERM;
3561  
3562  	sa = memdup_user(arg, sizeof(*sa));
3563  	if (IS_ERR(sa))
3564  		return PTR_ERR(sa);
3565  
3566  	if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
3567  		ret = mnt_want_write_file(file);
3568  		if (ret)
3569  			goto out;
3570  	}
3571  
3572  	ret = btrfs_scrub_dev(fs_info, sa->devid, sa->start, sa->end,
3573  			      &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
3574  			      0);
3575  
3576  	/*
3577  	 * Copy scrub args to user space even if btrfs_scrub_dev() returned an
3578  	 * error. This is important as it allows user space to know how much
3579  	 * progress scrub has done. For example, if scrub is canceled we get
3580  	 * -ECANCELED from btrfs_scrub_dev() and return that error back to user
3581  	 * space. Later user space can inspect the progress from the structure
3582  	 * btrfs_ioctl_scrub_args and resume scrub from where it left off
3583  	 * previously (btrfs-progs does this).
3584  	 * If we fail to copy the btrfs_ioctl_scrub_args structure to user space
3585  	 * then return -EFAULT to signal the structure was not copied or it may
3586  	 * be corrupt and unreliable due to a partial copy.
3587  	 */
3588  	if (copy_to_user(arg, sa, sizeof(*sa)))
3589  		ret = -EFAULT;
3590  
3591  	if (!(sa->flags & BTRFS_SCRUB_READONLY))
3592  		mnt_drop_write_file(file);
3593  out:
3594  	kfree(sa);
3595  	return ret;
3596  }
3597  
3598  static long btrfs_ioctl_scrub_cancel(struct btrfs_fs_info *fs_info)
3599  {
3600  	if (!capable(CAP_SYS_ADMIN))
3601  		return -EPERM;
3602  
3603  	return btrfs_scrub_cancel(fs_info);
3604  }
3605  
3606  static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
3607  				       void __user *arg)
3608  {
3609  	struct btrfs_ioctl_scrub_args *sa;
3610  	int ret;
3611  
3612  	if (!capable(CAP_SYS_ADMIN))
3613  		return -EPERM;
3614  
3615  	sa = memdup_user(arg, sizeof(*sa));
3616  	if (IS_ERR(sa))
3617  		return PTR_ERR(sa);
3618  
3619  	ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
3620  
3621  	if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
3622  		ret = -EFAULT;
3623  
3624  	kfree(sa);
3625  	return ret;
3626  }
3627  
3628  static long btrfs_ioctl_get_dev_stats(struct btrfs_fs_info *fs_info,
3629  				      void __user *arg)
3630  {
3631  	struct btrfs_ioctl_get_dev_stats *sa;
3632  	int ret;
3633  
3634  	sa = memdup_user(arg, sizeof(*sa));
3635  	if (IS_ERR(sa))
3636  		return PTR_ERR(sa);
3637  
3638  	if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
3639  		kfree(sa);
3640  		return -EPERM;
3641  	}
3642  
3643  	ret = btrfs_get_dev_stats(fs_info, sa);
3644  
3645  	if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
3646  		ret = -EFAULT;
3647  
3648  	kfree(sa);
3649  	return ret;
3650  }
3651  
3652  static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
3653  				    void __user *arg)
3654  {
3655  	struct btrfs_ioctl_dev_replace_args *p;
3656  	int ret;
3657  
3658  	if (!capable(CAP_SYS_ADMIN))
3659  		return -EPERM;
3660  
3661  	p = memdup_user(arg, sizeof(*p));
3662  	if (IS_ERR(p))
3663  		return PTR_ERR(p);
3664  
3665  	switch (p->cmd) {
3666  	case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
3667  		if (sb_rdonly(fs_info->sb)) {
3668  			ret = -EROFS;
3669  			goto out;
3670  		}
3671  		if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3672  			ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3673  		} else {
3674  			ret = btrfs_dev_replace_by_ioctl(fs_info, p);
3675  			clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3676  		}
3677  		break;
3678  	case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
3679  		btrfs_dev_replace_status(fs_info, p);
3680  		ret = 0;
3681  		break;
3682  	case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
3683  		p->result = btrfs_dev_replace_cancel(fs_info);
3684  		ret = 0;
3685  		break;
3686  	default:
3687  		ret = -EINVAL;
3688  		break;
3689  	}
3690  
3691  	if ((ret == 0 || ret == -ECANCELED) && copy_to_user(arg, p, sizeof(*p)))
3692  		ret = -EFAULT;
3693  out:
3694  	kfree(p);
3695  	return ret;
3696  }
3697  
3698  static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
3699  {
3700  	int ret = 0;
3701  	int i;
3702  	u64 rel_ptr;
3703  	int size;
3704  	struct btrfs_ioctl_ino_path_args *ipa = NULL;
3705  	struct inode_fs_paths *ipath = NULL;
3706  	struct btrfs_path *path;
3707  
3708  	if (!capable(CAP_DAC_READ_SEARCH))
3709  		return -EPERM;
3710  
3711  	path = btrfs_alloc_path();
3712  	if (!path) {
3713  		ret = -ENOMEM;
3714  		goto out;
3715  	}
3716  
3717  	ipa = memdup_user(arg, sizeof(*ipa));
3718  	if (IS_ERR(ipa)) {
3719  		ret = PTR_ERR(ipa);
3720  		ipa = NULL;
3721  		goto out;
3722  	}
3723  
3724  	size = min_t(u32, ipa->size, 4096);
3725  	ipath = init_ipath(size, root, path);
3726  	if (IS_ERR(ipath)) {
3727  		ret = PTR_ERR(ipath);
3728  		ipath = NULL;
3729  		goto out;
3730  	}
3731  
3732  	ret = paths_from_inode(ipa->inum, ipath);
3733  	if (ret < 0)
3734  		goto out;
3735  
3736  	for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
3737  		rel_ptr = ipath->fspath->val[i] -
3738  			  (u64)(unsigned long)ipath->fspath->val;
3739  		ipath->fspath->val[i] = rel_ptr;
3740  	}
3741  
3742  	ret = copy_to_user((void __user *)(unsigned long)ipa->fspath,
3743  			   ipath->fspath, size);
3744  	if (ret) {
3745  		ret = -EFAULT;
3746  		goto out;
3747  	}
3748  
3749  out:
3750  	btrfs_free_path(path);
3751  	free_ipath(ipath);
3752  	kfree(ipa);
3753  
3754  	return ret;
3755  }
3756  
3757  static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
3758  {
3759  	struct btrfs_data_container *inodes = ctx;
3760  	const size_t c = 3 * sizeof(u64);
3761  
3762  	if (inodes->bytes_left >= c) {
3763  		inodes->bytes_left -= c;
3764  		inodes->val[inodes->elem_cnt] = inum;
3765  		inodes->val[inodes->elem_cnt + 1] = offset;
3766  		inodes->val[inodes->elem_cnt + 2] = root;
3767  		inodes->elem_cnt += 3;
3768  	} else {
3769  		inodes->bytes_missing += c - inodes->bytes_left;
3770  		inodes->bytes_left = 0;
3771  		inodes->elem_missed += 3;
3772  	}
3773  
3774  	return 0;
3775  }
3776  
3777  static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
3778  					void __user *arg, int version)
3779  {
3780  	int ret = 0;
3781  	int size;
3782  	struct btrfs_ioctl_logical_ino_args *loi;
3783  	struct btrfs_data_container *inodes = NULL;
3784  	struct btrfs_path *path = NULL;
3785  	bool ignore_offset;
3786  
3787  	if (!capable(CAP_SYS_ADMIN))
3788  		return -EPERM;
3789  
3790  	loi = memdup_user(arg, sizeof(*loi));
3791  	if (IS_ERR(loi))
3792  		return PTR_ERR(loi);
3793  
3794  	if (version == 1) {
3795  		ignore_offset = false;
3796  		size = min_t(u32, loi->size, SZ_64K);
3797  	} else {
3798  		/* All reserved bits must be 0 for now */
3799  		if (memchr_inv(loi->reserved, 0, sizeof(loi->reserved))) {
3800  			ret = -EINVAL;
3801  			goto out_loi;
3802  		}
3803  		/* Only accept flags we have defined so far */
3804  		if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) {
3805  			ret = -EINVAL;
3806  			goto out_loi;
3807  		}
3808  		ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET;
3809  		size = min_t(u32, loi->size, SZ_16M);
3810  	}
3811  
3812  	path = btrfs_alloc_path();
3813  	if (!path) {
3814  		ret = -ENOMEM;
3815  		goto out;
3816  	}
3817  
3818  	inodes = init_data_container(size);
3819  	if (IS_ERR(inodes)) {
3820  		ret = PTR_ERR(inodes);
3821  		inodes = NULL;
3822  		goto out;
3823  	}
3824  
3825  	ret = iterate_inodes_from_logical(loi->logical, fs_info, path,
3826  					  build_ino_list, inodes, ignore_offset);
3827  	if (ret == -EINVAL)
3828  		ret = -ENOENT;
3829  	if (ret < 0)
3830  		goto out;
3831  
3832  	ret = copy_to_user((void __user *)(unsigned long)loi->inodes, inodes,
3833  			   size);
3834  	if (ret)
3835  		ret = -EFAULT;
3836  
3837  out:
3838  	btrfs_free_path(path);
3839  	kvfree(inodes);
3840  out_loi:
3841  	kfree(loi);
3842  
3843  	return ret;
3844  }
3845  
3846  void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
3847  			       struct btrfs_ioctl_balance_args *bargs)
3848  {
3849  	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3850  
3851  	bargs->flags = bctl->flags;
3852  
3853  	if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags))
3854  		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
3855  	if (atomic_read(&fs_info->balance_pause_req))
3856  		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
3857  	if (atomic_read(&fs_info->balance_cancel_req))
3858  		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
3859  
3860  	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
3861  	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
3862  	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
3863  
3864  	spin_lock(&fs_info->balance_lock);
3865  	memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
3866  	spin_unlock(&fs_info->balance_lock);
3867  }
3868  
3869  static long btrfs_ioctl_balance(struct file *file, void __user *arg)
3870  {
3871  	struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
3872  	struct btrfs_fs_info *fs_info = root->fs_info;
3873  	struct btrfs_ioctl_balance_args *bargs;
3874  	struct btrfs_balance_control *bctl;
3875  	bool need_unlock; /* for mut. excl. ops lock */
3876  	int ret;
3877  
3878  	if (!capable(CAP_SYS_ADMIN))
3879  		return -EPERM;
3880  
3881  	ret = mnt_want_write_file(file);
3882  	if (ret)
3883  		return ret;
3884  
3885  again:
3886  	if (!test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3887  		mutex_lock(&fs_info->balance_mutex);
3888  		need_unlock = true;
3889  		goto locked;
3890  	}
3891  
3892  	/*
3893  	 * mut. excl. ops lock is locked.  Three possibilities:
3894  	 *   (1) some other op is running
3895  	 *   (2) balance is running
3896  	 *   (3) balance is paused -- special case (think resume)
3897  	 */
3898  	mutex_lock(&fs_info->balance_mutex);
3899  	if (fs_info->balance_ctl) {
3900  		/* this is either (2) or (3) */
3901  		if (!test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
3902  			mutex_unlock(&fs_info->balance_mutex);
3903  			/*
3904  			 * Lock released to allow other waiters to continue,
3905  			 * we'll reexamine the status again.
3906  			 */
3907  			mutex_lock(&fs_info->balance_mutex);
3908  
3909  			if (fs_info->balance_ctl &&
3910  			    !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
3911  				/* this is (3) */
3912  				need_unlock = false;
3913  				goto locked;
3914  			}
3915  
3916  			mutex_unlock(&fs_info->balance_mutex);
3917  			goto again;
3918  		} else {
3919  			/* this is (2) */
3920  			mutex_unlock(&fs_info->balance_mutex);
3921  			ret = -EINPROGRESS;
3922  			goto out;
3923  		}
3924  	} else {
3925  		/* this is (1) */
3926  		mutex_unlock(&fs_info->balance_mutex);
3927  		ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3928  		goto out;
3929  	}
3930  
3931  locked:
3932  	BUG_ON(!test_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
3933  
3934  	if (arg) {
3935  		bargs = memdup_user(arg, sizeof(*bargs));
3936  		if (IS_ERR(bargs)) {
3937  			ret = PTR_ERR(bargs);
3938  			goto out_unlock;
3939  		}
3940  
3941  		if (bargs->flags & BTRFS_BALANCE_RESUME) {
3942  			if (!fs_info->balance_ctl) {
3943  				ret = -ENOTCONN;
3944  				goto out_bargs;
3945  			}
3946  
3947  			bctl = fs_info->balance_ctl;
3948  			spin_lock(&fs_info->balance_lock);
3949  			bctl->flags |= BTRFS_BALANCE_RESUME;
3950  			spin_unlock(&fs_info->balance_lock);
3951  
3952  			goto do_balance;
3953  		}
3954  	} else {
3955  		bargs = NULL;
3956  	}
3957  
3958  	if (fs_info->balance_ctl) {
3959  		ret = -EINPROGRESS;
3960  		goto out_bargs;
3961  	}
3962  
3963  	bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
3964  	if (!bctl) {
3965  		ret = -ENOMEM;
3966  		goto out_bargs;
3967  	}
3968  
3969  	if (arg) {
3970  		memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
3971  		memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
3972  		memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
3973  
3974  		bctl->flags = bargs->flags;
3975  	} else {
3976  		/* balance everything - no filters */
3977  		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
3978  	}
3979  
3980  	if (bctl->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
3981  		ret = -EINVAL;
3982  		goto out_bctl;
3983  	}
3984  
3985  do_balance:
3986  	/*
3987  	 * Ownership of bctl and filesystem flag BTRFS_FS_EXCL_OP goes to
3988  	 * btrfs_balance.  bctl is freed in reset_balance_state, or, if
3989  	 * restriper was paused all the way until unmount, in free_fs_info.
3990  	 * The flag should be cleared after reset_balance_state.
3991  	 */
3992  	need_unlock = false;
3993  
3994  	ret = btrfs_balance(fs_info, bctl, bargs);
3995  	bctl = NULL;
3996  
3997  	if ((ret == 0 || ret == -ECANCELED) && arg) {
3998  		if (copy_to_user(arg, bargs, sizeof(*bargs)))
3999  			ret = -EFAULT;
4000  	}
4001  
4002  out_bctl:
4003  	kfree(bctl);
4004  out_bargs:
4005  	kfree(bargs);
4006  out_unlock:
4007  	mutex_unlock(&fs_info->balance_mutex);
4008  	if (need_unlock)
4009  		clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
4010  out:
4011  	mnt_drop_write_file(file);
4012  	return ret;
4013  }
4014  
4015  static long btrfs_ioctl_balance_ctl(struct btrfs_fs_info *fs_info, int cmd)
4016  {
4017  	if (!capable(CAP_SYS_ADMIN))
4018  		return -EPERM;
4019  
4020  	switch (cmd) {
4021  	case BTRFS_BALANCE_CTL_PAUSE:
4022  		return btrfs_pause_balance(fs_info);
4023  	case BTRFS_BALANCE_CTL_CANCEL:
4024  		return btrfs_cancel_balance(fs_info);
4025  	}
4026  
4027  	return -EINVAL;
4028  }
4029  
4030  static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
4031  					 void __user *arg)
4032  {
4033  	struct btrfs_ioctl_balance_args *bargs;
4034  	int ret = 0;
4035  
4036  	if (!capable(CAP_SYS_ADMIN))
4037  		return -EPERM;
4038  
4039  	mutex_lock(&fs_info->balance_mutex);
4040  	if (!fs_info->balance_ctl) {
4041  		ret = -ENOTCONN;
4042  		goto out;
4043  	}
4044  
4045  	bargs = kzalloc(sizeof(*bargs), GFP_KERNEL);
4046  	if (!bargs) {
4047  		ret = -ENOMEM;
4048  		goto out;
4049  	}
4050  
4051  	btrfs_update_ioctl_balance_args(fs_info, bargs);
4052  
4053  	if (copy_to_user(arg, bargs, sizeof(*bargs)))
4054  		ret = -EFAULT;
4055  
4056  	kfree(bargs);
4057  out:
4058  	mutex_unlock(&fs_info->balance_mutex);
4059  	return ret;
4060  }
4061  
4062  static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
4063  {
4064  	struct inode *inode = file_inode(file);
4065  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4066  	struct btrfs_ioctl_quota_ctl_args *sa;
4067  	int ret;
4068  
4069  	if (!capable(CAP_SYS_ADMIN))
4070  		return -EPERM;
4071  
4072  	ret = mnt_want_write_file(file);
4073  	if (ret)
4074  		return ret;
4075  
4076  	sa = memdup_user(arg, sizeof(*sa));
4077  	if (IS_ERR(sa)) {
4078  		ret = PTR_ERR(sa);
4079  		goto drop_write;
4080  	}
4081  
4082  	down_write(&fs_info->subvol_sem);
4083  
4084  	switch (sa->cmd) {
4085  	case BTRFS_QUOTA_CTL_ENABLE:
4086  		ret = btrfs_quota_enable(fs_info);
4087  		break;
4088  	case BTRFS_QUOTA_CTL_DISABLE:
4089  		ret = btrfs_quota_disable(fs_info);
4090  		break;
4091  	default:
4092  		ret = -EINVAL;
4093  		break;
4094  	}
4095  
4096  	kfree(sa);
4097  	up_write(&fs_info->subvol_sem);
4098  drop_write:
4099  	mnt_drop_write_file(file);
4100  	return ret;
4101  }
4102  
4103  static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
4104  {
4105  	struct inode *inode = file_inode(file);
4106  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4107  	struct btrfs_root *root = BTRFS_I(inode)->root;
4108  	struct btrfs_ioctl_qgroup_assign_args *sa;
4109  	struct btrfs_trans_handle *trans;
4110  	int ret;
4111  	int err;
4112  
4113  	if (!capable(CAP_SYS_ADMIN))
4114  		return -EPERM;
4115  
4116  	ret = mnt_want_write_file(file);
4117  	if (ret)
4118  		return ret;
4119  
4120  	sa = memdup_user(arg, sizeof(*sa));
4121  	if (IS_ERR(sa)) {
4122  		ret = PTR_ERR(sa);
4123  		goto drop_write;
4124  	}
4125  
4126  	trans = btrfs_join_transaction(root);
4127  	if (IS_ERR(trans)) {
4128  		ret = PTR_ERR(trans);
4129  		goto out;
4130  	}
4131  
4132  	if (sa->assign) {
4133  		ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst);
4134  	} else {
4135  		ret = btrfs_del_qgroup_relation(trans, sa->src, sa->dst);
4136  	}
4137  
4138  	/* update qgroup status and info */
4139  	err = btrfs_run_qgroups(trans);
4140  	if (err < 0)
4141  		btrfs_handle_fs_error(fs_info, err,
4142  				      "failed to update qgroup status and info");
4143  	err = btrfs_end_transaction(trans);
4144  	if (err && !ret)
4145  		ret = err;
4146  
4147  out:
4148  	kfree(sa);
4149  drop_write:
4150  	mnt_drop_write_file(file);
4151  	return ret;
4152  }
4153  
4154  static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
4155  {
4156  	struct inode *inode = file_inode(file);
4157  	struct btrfs_root *root = BTRFS_I(inode)->root;
4158  	struct btrfs_ioctl_qgroup_create_args *sa;
4159  	struct btrfs_trans_handle *trans;
4160  	int ret;
4161  	int err;
4162  
4163  	if (!capable(CAP_SYS_ADMIN))
4164  		return -EPERM;
4165  
4166  	ret = mnt_want_write_file(file);
4167  	if (ret)
4168  		return ret;
4169  
4170  	sa = memdup_user(arg, sizeof(*sa));
4171  	if (IS_ERR(sa)) {
4172  		ret = PTR_ERR(sa);
4173  		goto drop_write;
4174  	}
4175  
4176  	if (!sa->qgroupid) {
4177  		ret = -EINVAL;
4178  		goto out;
4179  	}
4180  
4181  	trans = btrfs_join_transaction(root);
4182  	if (IS_ERR(trans)) {
4183  		ret = PTR_ERR(trans);
4184  		goto out;
4185  	}
4186  
4187  	if (sa->create) {
4188  		ret = btrfs_create_qgroup(trans, sa->qgroupid);
4189  	} else {
4190  		ret = btrfs_remove_qgroup(trans, sa->qgroupid);
4191  	}
4192  
4193  	err = btrfs_end_transaction(trans);
4194  	if (err && !ret)
4195  		ret = err;
4196  
4197  out:
4198  	kfree(sa);
4199  drop_write:
4200  	mnt_drop_write_file(file);
4201  	return ret;
4202  }
4203  
4204  static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
4205  {
4206  	struct inode *inode = file_inode(file);
4207  	struct btrfs_root *root = BTRFS_I(inode)->root;
4208  	struct btrfs_ioctl_qgroup_limit_args *sa;
4209  	struct btrfs_trans_handle *trans;
4210  	int ret;
4211  	int err;
4212  	u64 qgroupid;
4213  
4214  	if (!capable(CAP_SYS_ADMIN))
4215  		return -EPERM;
4216  
4217  	ret = mnt_want_write_file(file);
4218  	if (ret)
4219  		return ret;
4220  
4221  	sa = memdup_user(arg, sizeof(*sa));
4222  	if (IS_ERR(sa)) {
4223  		ret = PTR_ERR(sa);
4224  		goto drop_write;
4225  	}
4226  
4227  	trans = btrfs_join_transaction(root);
4228  	if (IS_ERR(trans)) {
4229  		ret = PTR_ERR(trans);
4230  		goto out;
4231  	}
4232  
4233  	qgroupid = sa->qgroupid;
4234  	if (!qgroupid) {
4235  		/* take the current subvol as qgroup */
4236  		qgroupid = root->root_key.objectid;
4237  	}
4238  
4239  	ret = btrfs_limit_qgroup(trans, qgroupid, &sa->lim);
4240  
4241  	err = btrfs_end_transaction(trans);
4242  	if (err && !ret)
4243  		ret = err;
4244  
4245  out:
4246  	kfree(sa);
4247  drop_write:
4248  	mnt_drop_write_file(file);
4249  	return ret;
4250  }
4251  
4252  static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
4253  {
4254  	struct inode *inode = file_inode(file);
4255  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4256  	struct btrfs_ioctl_quota_rescan_args *qsa;
4257  	int ret;
4258  
4259  	if (!capable(CAP_SYS_ADMIN))
4260  		return -EPERM;
4261  
4262  	ret = mnt_want_write_file(file);
4263  	if (ret)
4264  		return ret;
4265  
4266  	qsa = memdup_user(arg, sizeof(*qsa));
4267  	if (IS_ERR(qsa)) {
4268  		ret = PTR_ERR(qsa);
4269  		goto drop_write;
4270  	}
4271  
4272  	if (qsa->flags) {
4273  		ret = -EINVAL;
4274  		goto out;
4275  	}
4276  
4277  	ret = btrfs_qgroup_rescan(fs_info);
4278  
4279  out:
4280  	kfree(qsa);
4281  drop_write:
4282  	mnt_drop_write_file(file);
4283  	return ret;
4284  }
4285  
4286  static long btrfs_ioctl_quota_rescan_status(struct btrfs_fs_info *fs_info,
4287  						void __user *arg)
4288  {
4289  	struct btrfs_ioctl_quota_rescan_args *qsa;
4290  	int ret = 0;
4291  
4292  	if (!capable(CAP_SYS_ADMIN))
4293  		return -EPERM;
4294  
4295  	qsa = kzalloc(sizeof(*qsa), GFP_KERNEL);
4296  	if (!qsa)
4297  		return -ENOMEM;
4298  
4299  	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
4300  		qsa->flags = 1;
4301  		qsa->progress = fs_info->qgroup_rescan_progress.objectid;
4302  	}
4303  
4304  	if (copy_to_user(arg, qsa, sizeof(*qsa)))
4305  		ret = -EFAULT;
4306  
4307  	kfree(qsa);
4308  	return ret;
4309  }
4310  
4311  static long btrfs_ioctl_quota_rescan_wait(struct btrfs_fs_info *fs_info,
4312  						void __user *arg)
4313  {
4314  	if (!capable(CAP_SYS_ADMIN))
4315  		return -EPERM;
4316  
4317  	return btrfs_qgroup_wait_for_completion(fs_info, true);
4318  }
4319  
4320  static long _btrfs_ioctl_set_received_subvol(struct file *file,
4321  					    struct btrfs_ioctl_received_subvol_args *sa)
4322  {
4323  	struct inode *inode = file_inode(file);
4324  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4325  	struct btrfs_root *root = BTRFS_I(inode)->root;
4326  	struct btrfs_root_item *root_item = &root->root_item;
4327  	struct btrfs_trans_handle *trans;
4328  	struct timespec64 ct = current_time(inode);
4329  	int ret = 0;
4330  	int received_uuid_changed;
4331  
4332  	if (!inode_owner_or_capable(inode))
4333  		return -EPERM;
4334  
4335  	ret = mnt_want_write_file(file);
4336  	if (ret < 0)
4337  		return ret;
4338  
4339  	down_write(&fs_info->subvol_sem);
4340  
4341  	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
4342  		ret = -EINVAL;
4343  		goto out;
4344  	}
4345  
4346  	if (btrfs_root_readonly(root)) {
4347  		ret = -EROFS;
4348  		goto out;
4349  	}
4350  
4351  	/*
4352  	 * 1 - root item
4353  	 * 2 - uuid items (received uuid + subvol uuid)
4354  	 */
4355  	trans = btrfs_start_transaction(root, 3);
4356  	if (IS_ERR(trans)) {
4357  		ret = PTR_ERR(trans);
4358  		trans = NULL;
4359  		goto out;
4360  	}
4361  
4362  	sa->rtransid = trans->transid;
4363  	sa->rtime.sec = ct.tv_sec;
4364  	sa->rtime.nsec = ct.tv_nsec;
4365  
4366  	received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
4367  				       BTRFS_UUID_SIZE);
4368  	if (received_uuid_changed &&
4369  	    !btrfs_is_empty_uuid(root_item->received_uuid)) {
4370  		ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid,
4371  					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4372  					  root->root_key.objectid);
4373  		if (ret && ret != -ENOENT) {
4374  		        btrfs_abort_transaction(trans, ret);
4375  		        btrfs_end_transaction(trans);
4376  		        goto out;
4377  		}
4378  	}
4379  	memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
4380  	btrfs_set_root_stransid(root_item, sa->stransid);
4381  	btrfs_set_root_rtransid(root_item, sa->rtransid);
4382  	btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
4383  	btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
4384  	btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
4385  	btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
4386  
4387  	ret = btrfs_update_root(trans, fs_info->tree_root,
4388  				&root->root_key, &root->root_item);
4389  	if (ret < 0) {
4390  		btrfs_end_transaction(trans);
4391  		goto out;
4392  	}
4393  	if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
4394  		ret = btrfs_uuid_tree_add(trans, sa->uuid,
4395  					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4396  					  root->root_key.objectid);
4397  		if (ret < 0 && ret != -EEXIST) {
4398  			btrfs_abort_transaction(trans, ret);
4399  			btrfs_end_transaction(trans);
4400  			goto out;
4401  		}
4402  	}
4403  	ret = btrfs_commit_transaction(trans);
4404  out:
4405  	up_write(&fs_info->subvol_sem);
4406  	mnt_drop_write_file(file);
4407  	return ret;
4408  }
4409  
4410  #ifdef CONFIG_64BIT
4411  static long btrfs_ioctl_set_received_subvol_32(struct file *file,
4412  						void __user *arg)
4413  {
4414  	struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
4415  	struct btrfs_ioctl_received_subvol_args *args64 = NULL;
4416  	int ret = 0;
4417  
4418  	args32 = memdup_user(arg, sizeof(*args32));
4419  	if (IS_ERR(args32))
4420  		return PTR_ERR(args32);
4421  
4422  	args64 = kmalloc(sizeof(*args64), GFP_KERNEL);
4423  	if (!args64) {
4424  		ret = -ENOMEM;
4425  		goto out;
4426  	}
4427  
4428  	memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
4429  	args64->stransid = args32->stransid;
4430  	args64->rtransid = args32->rtransid;
4431  	args64->stime.sec = args32->stime.sec;
4432  	args64->stime.nsec = args32->stime.nsec;
4433  	args64->rtime.sec = args32->rtime.sec;
4434  	args64->rtime.nsec = args32->rtime.nsec;
4435  	args64->flags = args32->flags;
4436  
4437  	ret = _btrfs_ioctl_set_received_subvol(file, args64);
4438  	if (ret)
4439  		goto out;
4440  
4441  	memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
4442  	args32->stransid = args64->stransid;
4443  	args32->rtransid = args64->rtransid;
4444  	args32->stime.sec = args64->stime.sec;
4445  	args32->stime.nsec = args64->stime.nsec;
4446  	args32->rtime.sec = args64->rtime.sec;
4447  	args32->rtime.nsec = args64->rtime.nsec;
4448  	args32->flags = args64->flags;
4449  
4450  	ret = copy_to_user(arg, args32, sizeof(*args32));
4451  	if (ret)
4452  		ret = -EFAULT;
4453  
4454  out:
4455  	kfree(args32);
4456  	kfree(args64);
4457  	return ret;
4458  }
4459  #endif
4460  
4461  static long btrfs_ioctl_set_received_subvol(struct file *file,
4462  					    void __user *arg)
4463  {
4464  	struct btrfs_ioctl_received_subvol_args *sa = NULL;
4465  	int ret = 0;
4466  
4467  	sa = memdup_user(arg, sizeof(*sa));
4468  	if (IS_ERR(sa))
4469  		return PTR_ERR(sa);
4470  
4471  	ret = _btrfs_ioctl_set_received_subvol(file, sa);
4472  
4473  	if (ret)
4474  		goto out;
4475  
4476  	ret = copy_to_user(arg, sa, sizeof(*sa));
4477  	if (ret)
4478  		ret = -EFAULT;
4479  
4480  out:
4481  	kfree(sa);
4482  	return ret;
4483  }
4484  
4485  static int btrfs_ioctl_get_fslabel(struct btrfs_fs_info *fs_info,
4486  					void __user *arg)
4487  {
4488  	size_t len;
4489  	int ret;
4490  	char label[BTRFS_LABEL_SIZE];
4491  
4492  	spin_lock(&fs_info->super_lock);
4493  	memcpy(label, fs_info->super_copy->label, BTRFS_LABEL_SIZE);
4494  	spin_unlock(&fs_info->super_lock);
4495  
4496  	len = strnlen(label, BTRFS_LABEL_SIZE);
4497  
4498  	if (len == BTRFS_LABEL_SIZE) {
4499  		btrfs_warn(fs_info,
4500  			   "label is too long, return the first %zu bytes",
4501  			   --len);
4502  	}
4503  
4504  	ret = copy_to_user(arg, label, len);
4505  
4506  	return ret ? -EFAULT : 0;
4507  }
4508  
4509  static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
4510  {
4511  	struct inode *inode = file_inode(file);
4512  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4513  	struct btrfs_root *root = BTRFS_I(inode)->root;
4514  	struct btrfs_super_block *super_block = fs_info->super_copy;
4515  	struct btrfs_trans_handle *trans;
4516  	char label[BTRFS_LABEL_SIZE];
4517  	int ret;
4518  
4519  	if (!capable(CAP_SYS_ADMIN))
4520  		return -EPERM;
4521  
4522  	if (copy_from_user(label, arg, sizeof(label)))
4523  		return -EFAULT;
4524  
4525  	if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
4526  		btrfs_err(fs_info,
4527  			  "unable to set label with more than %d bytes",
4528  			  BTRFS_LABEL_SIZE - 1);
4529  		return -EINVAL;
4530  	}
4531  
4532  	ret = mnt_want_write_file(file);
4533  	if (ret)
4534  		return ret;
4535  
4536  	trans = btrfs_start_transaction(root, 0);
4537  	if (IS_ERR(trans)) {
4538  		ret = PTR_ERR(trans);
4539  		goto out_unlock;
4540  	}
4541  
4542  	spin_lock(&fs_info->super_lock);
4543  	strcpy(super_block->label, label);
4544  	spin_unlock(&fs_info->super_lock);
4545  	ret = btrfs_commit_transaction(trans);
4546  
4547  out_unlock:
4548  	mnt_drop_write_file(file);
4549  	return ret;
4550  }
4551  
4552  #define INIT_FEATURE_FLAGS(suffix) \
4553  	{ .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
4554  	  .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
4555  	  .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
4556  
4557  int btrfs_ioctl_get_supported_features(void __user *arg)
4558  {
4559  	static const struct btrfs_ioctl_feature_flags features[3] = {
4560  		INIT_FEATURE_FLAGS(SUPP),
4561  		INIT_FEATURE_FLAGS(SAFE_SET),
4562  		INIT_FEATURE_FLAGS(SAFE_CLEAR)
4563  	};
4564  
4565  	if (copy_to_user(arg, &features, sizeof(features)))
4566  		return -EFAULT;
4567  
4568  	return 0;
4569  }
4570  
4571  static int btrfs_ioctl_get_features(struct btrfs_fs_info *fs_info,
4572  					void __user *arg)
4573  {
4574  	struct btrfs_super_block *super_block = fs_info->super_copy;
4575  	struct btrfs_ioctl_feature_flags features;
4576  
4577  	features.compat_flags = btrfs_super_compat_flags(super_block);
4578  	features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
4579  	features.incompat_flags = btrfs_super_incompat_flags(super_block);
4580  
4581  	if (copy_to_user(arg, &features, sizeof(features)))
4582  		return -EFAULT;
4583  
4584  	return 0;
4585  }
4586  
4587  static int check_feature_bits(struct btrfs_fs_info *fs_info,
4588  			      enum btrfs_feature_set set,
4589  			      u64 change_mask, u64 flags, u64 supported_flags,
4590  			      u64 safe_set, u64 safe_clear)
4591  {
4592  	const char *type = btrfs_feature_set_name(set);
4593  	char *names;
4594  	u64 disallowed, unsupported;
4595  	u64 set_mask = flags & change_mask;
4596  	u64 clear_mask = ~flags & change_mask;
4597  
4598  	unsupported = set_mask & ~supported_flags;
4599  	if (unsupported) {
4600  		names = btrfs_printable_features(set, unsupported);
4601  		if (names) {
4602  			btrfs_warn(fs_info,
4603  				   "this kernel does not support the %s feature bit%s",
4604  				   names, strchr(names, ',') ? "s" : "");
4605  			kfree(names);
4606  		} else
4607  			btrfs_warn(fs_info,
4608  				   "this kernel does not support %s bits 0x%llx",
4609  				   type, unsupported);
4610  		return -EOPNOTSUPP;
4611  	}
4612  
4613  	disallowed = set_mask & ~safe_set;
4614  	if (disallowed) {
4615  		names = btrfs_printable_features(set, disallowed);
4616  		if (names) {
4617  			btrfs_warn(fs_info,
4618  				   "can't set the %s feature bit%s while mounted",
4619  				   names, strchr(names, ',') ? "s" : "");
4620  			kfree(names);
4621  		} else
4622  			btrfs_warn(fs_info,
4623  				   "can't set %s bits 0x%llx while mounted",
4624  				   type, disallowed);
4625  		return -EPERM;
4626  	}
4627  
4628  	disallowed = clear_mask & ~safe_clear;
4629  	if (disallowed) {
4630  		names = btrfs_printable_features(set, disallowed);
4631  		if (names) {
4632  			btrfs_warn(fs_info,
4633  				   "can't clear the %s feature bit%s while mounted",
4634  				   names, strchr(names, ',') ? "s" : "");
4635  			kfree(names);
4636  		} else
4637  			btrfs_warn(fs_info,
4638  				   "can't clear %s bits 0x%llx while mounted",
4639  				   type, disallowed);
4640  		return -EPERM;
4641  	}
4642  
4643  	return 0;
4644  }
4645  
4646  #define check_feature(fs_info, change_mask, flags, mask_base)	\
4647  check_feature_bits(fs_info, FEAT_##mask_base, change_mask, flags,	\
4648  		   BTRFS_FEATURE_ ## mask_base ## _SUPP,	\
4649  		   BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,	\
4650  		   BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
4651  
4652  static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
4653  {
4654  	struct inode *inode = file_inode(file);
4655  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4656  	struct btrfs_root *root = BTRFS_I(inode)->root;
4657  	struct btrfs_super_block *super_block = fs_info->super_copy;
4658  	struct btrfs_ioctl_feature_flags flags[2];
4659  	struct btrfs_trans_handle *trans;
4660  	u64 newflags;
4661  	int ret;
4662  
4663  	if (!capable(CAP_SYS_ADMIN))
4664  		return -EPERM;
4665  
4666  	if (copy_from_user(flags, arg, sizeof(flags)))
4667  		return -EFAULT;
4668  
4669  	/* Nothing to do */
4670  	if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
4671  	    !flags[0].incompat_flags)
4672  		return 0;
4673  
4674  	ret = check_feature(fs_info, flags[0].compat_flags,
4675  			    flags[1].compat_flags, COMPAT);
4676  	if (ret)
4677  		return ret;
4678  
4679  	ret = check_feature(fs_info, flags[0].compat_ro_flags,
4680  			    flags[1].compat_ro_flags, COMPAT_RO);
4681  	if (ret)
4682  		return ret;
4683  
4684  	ret = check_feature(fs_info, flags[0].incompat_flags,
4685  			    flags[1].incompat_flags, INCOMPAT);
4686  	if (ret)
4687  		return ret;
4688  
4689  	ret = mnt_want_write_file(file);
4690  	if (ret)
4691  		return ret;
4692  
4693  	trans = btrfs_start_transaction(root, 0);
4694  	if (IS_ERR(trans)) {
4695  		ret = PTR_ERR(trans);
4696  		goto out_drop_write;
4697  	}
4698  
4699  	spin_lock(&fs_info->super_lock);
4700  	newflags = btrfs_super_compat_flags(super_block);
4701  	newflags |= flags[0].compat_flags & flags[1].compat_flags;
4702  	newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
4703  	btrfs_set_super_compat_flags(super_block, newflags);
4704  
4705  	newflags = btrfs_super_compat_ro_flags(super_block);
4706  	newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
4707  	newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
4708  	btrfs_set_super_compat_ro_flags(super_block, newflags);
4709  
4710  	newflags = btrfs_super_incompat_flags(super_block);
4711  	newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
4712  	newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
4713  	btrfs_set_super_incompat_flags(super_block, newflags);
4714  	spin_unlock(&fs_info->super_lock);
4715  
4716  	ret = btrfs_commit_transaction(trans);
4717  out_drop_write:
4718  	mnt_drop_write_file(file);
4719  
4720  	return ret;
4721  }
4722  
4723  static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
4724  {
4725  	struct btrfs_ioctl_send_args *arg;
4726  	int ret;
4727  
4728  	if (compat) {
4729  #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4730  		struct btrfs_ioctl_send_args_32 args32;
4731  
4732  		ret = copy_from_user(&args32, argp, sizeof(args32));
4733  		if (ret)
4734  			return -EFAULT;
4735  		arg = kzalloc(sizeof(*arg), GFP_KERNEL);
4736  		if (!arg)
4737  			return -ENOMEM;
4738  		arg->send_fd = args32.send_fd;
4739  		arg->clone_sources_count = args32.clone_sources_count;
4740  		arg->clone_sources = compat_ptr(args32.clone_sources);
4741  		arg->parent_root = args32.parent_root;
4742  		arg->flags = args32.flags;
4743  		memcpy(arg->reserved, args32.reserved,
4744  		       sizeof(args32.reserved));
4745  #else
4746  		return -ENOTTY;
4747  #endif
4748  	} else {
4749  		arg = memdup_user(argp, sizeof(*arg));
4750  		if (IS_ERR(arg))
4751  			return PTR_ERR(arg);
4752  	}
4753  	ret = btrfs_ioctl_send(file, arg);
4754  	kfree(arg);
4755  	return ret;
4756  }
4757  
4758  long btrfs_ioctl(struct file *file, unsigned int
4759  		cmd, unsigned long arg)
4760  {
4761  	struct inode *inode = file_inode(file);
4762  	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4763  	struct btrfs_root *root = BTRFS_I(inode)->root;
4764  	void __user *argp = (void __user *)arg;
4765  
4766  	switch (cmd) {
4767  	case FS_IOC_GETFLAGS:
4768  		return btrfs_ioctl_getflags(file, argp);
4769  	case FS_IOC_SETFLAGS:
4770  		return btrfs_ioctl_setflags(file, argp);
4771  	case FS_IOC_GETVERSION:
4772  		return btrfs_ioctl_getversion(file, argp);
4773  	case FS_IOC_GETFSLABEL:
4774  		return btrfs_ioctl_get_fslabel(fs_info, argp);
4775  	case FS_IOC_SETFSLABEL:
4776  		return btrfs_ioctl_set_fslabel(file, argp);
4777  	case FITRIM:
4778  		return btrfs_ioctl_fitrim(fs_info, argp);
4779  	case BTRFS_IOC_SNAP_CREATE:
4780  		return btrfs_ioctl_snap_create(file, argp, 0);
4781  	case BTRFS_IOC_SNAP_CREATE_V2:
4782  		return btrfs_ioctl_snap_create_v2(file, argp, 0);
4783  	case BTRFS_IOC_SUBVOL_CREATE:
4784  		return btrfs_ioctl_snap_create(file, argp, 1);
4785  	case BTRFS_IOC_SUBVOL_CREATE_V2:
4786  		return btrfs_ioctl_snap_create_v2(file, argp, 1);
4787  	case BTRFS_IOC_SNAP_DESTROY:
4788  		return btrfs_ioctl_snap_destroy(file, argp, false);
4789  	case BTRFS_IOC_SNAP_DESTROY_V2:
4790  		return btrfs_ioctl_snap_destroy(file, argp, true);
4791  	case BTRFS_IOC_SUBVOL_GETFLAGS:
4792  		return btrfs_ioctl_subvol_getflags(file, argp);
4793  	case BTRFS_IOC_SUBVOL_SETFLAGS:
4794  		return btrfs_ioctl_subvol_setflags(file, argp);
4795  	case BTRFS_IOC_DEFAULT_SUBVOL:
4796  		return btrfs_ioctl_default_subvol(file, argp);
4797  	case BTRFS_IOC_DEFRAG:
4798  		return btrfs_ioctl_defrag(file, NULL);
4799  	case BTRFS_IOC_DEFRAG_RANGE:
4800  		return btrfs_ioctl_defrag(file, argp);
4801  	case BTRFS_IOC_RESIZE:
4802  		return btrfs_ioctl_resize(file, argp);
4803  	case BTRFS_IOC_ADD_DEV:
4804  		return btrfs_ioctl_add_dev(fs_info, argp);
4805  	case BTRFS_IOC_RM_DEV:
4806  		return btrfs_ioctl_rm_dev(file, argp);
4807  	case BTRFS_IOC_RM_DEV_V2:
4808  		return btrfs_ioctl_rm_dev_v2(file, argp);
4809  	case BTRFS_IOC_FS_INFO:
4810  		return btrfs_ioctl_fs_info(fs_info, argp);
4811  	case BTRFS_IOC_DEV_INFO:
4812  		return btrfs_ioctl_dev_info(fs_info, argp);
4813  	case BTRFS_IOC_BALANCE:
4814  		return btrfs_ioctl_balance(file, NULL);
4815  	case BTRFS_IOC_TREE_SEARCH:
4816  		return btrfs_ioctl_tree_search(file, argp);
4817  	case BTRFS_IOC_TREE_SEARCH_V2:
4818  		return btrfs_ioctl_tree_search_v2(file, argp);
4819  	case BTRFS_IOC_INO_LOOKUP:
4820  		return btrfs_ioctl_ino_lookup(file, argp);
4821  	case BTRFS_IOC_INO_PATHS:
4822  		return btrfs_ioctl_ino_to_path(root, argp);
4823  	case BTRFS_IOC_LOGICAL_INO:
4824  		return btrfs_ioctl_logical_to_ino(fs_info, argp, 1);
4825  	case BTRFS_IOC_LOGICAL_INO_V2:
4826  		return btrfs_ioctl_logical_to_ino(fs_info, argp, 2);
4827  	case BTRFS_IOC_SPACE_INFO:
4828  		return btrfs_ioctl_space_info(fs_info, argp);
4829  	case BTRFS_IOC_SYNC: {
4830  		int ret;
4831  
4832  		ret = btrfs_start_delalloc_roots(fs_info, -1);
4833  		if (ret)
4834  			return ret;
4835  		ret = btrfs_sync_fs(inode->i_sb, 1);
4836  		/*
4837  		 * The transaction thread may want to do more work,
4838  		 * namely it pokes the cleaner kthread that will start
4839  		 * processing uncleaned subvols.
4840  		 */
4841  		wake_up_process(fs_info->transaction_kthread);
4842  		return ret;
4843  	}
4844  	case BTRFS_IOC_START_SYNC:
4845  		return btrfs_ioctl_start_sync(root, argp);
4846  	case BTRFS_IOC_WAIT_SYNC:
4847  		return btrfs_ioctl_wait_sync(fs_info, argp);
4848  	case BTRFS_IOC_SCRUB:
4849  		return btrfs_ioctl_scrub(file, argp);
4850  	case BTRFS_IOC_SCRUB_CANCEL:
4851  		return btrfs_ioctl_scrub_cancel(fs_info);
4852  	case BTRFS_IOC_SCRUB_PROGRESS:
4853  		return btrfs_ioctl_scrub_progress(fs_info, argp);
4854  	case BTRFS_IOC_BALANCE_V2:
4855  		return btrfs_ioctl_balance(file, argp);
4856  	case BTRFS_IOC_BALANCE_CTL:
4857  		return btrfs_ioctl_balance_ctl(fs_info, arg);
4858  	case BTRFS_IOC_BALANCE_PROGRESS:
4859  		return btrfs_ioctl_balance_progress(fs_info, argp);
4860  	case BTRFS_IOC_SET_RECEIVED_SUBVOL:
4861  		return btrfs_ioctl_set_received_subvol(file, argp);
4862  #ifdef CONFIG_64BIT
4863  	case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
4864  		return btrfs_ioctl_set_received_subvol_32(file, argp);
4865  #endif
4866  	case BTRFS_IOC_SEND:
4867  		return _btrfs_ioctl_send(file, argp, false);
4868  #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4869  	case BTRFS_IOC_SEND_32:
4870  		return _btrfs_ioctl_send(file, argp, true);
4871  #endif
4872  	case BTRFS_IOC_GET_DEV_STATS:
4873  		return btrfs_ioctl_get_dev_stats(fs_info, argp);
4874  	case BTRFS_IOC_QUOTA_CTL:
4875  		return btrfs_ioctl_quota_ctl(file, argp);
4876  	case BTRFS_IOC_QGROUP_ASSIGN:
4877  		return btrfs_ioctl_qgroup_assign(file, argp);
4878  	case BTRFS_IOC_QGROUP_CREATE:
4879  		return btrfs_ioctl_qgroup_create(file, argp);
4880  	case BTRFS_IOC_QGROUP_LIMIT:
4881  		return btrfs_ioctl_qgroup_limit(file, argp);
4882  	case BTRFS_IOC_QUOTA_RESCAN:
4883  		return btrfs_ioctl_quota_rescan(file, argp);
4884  	case BTRFS_IOC_QUOTA_RESCAN_STATUS:
4885  		return btrfs_ioctl_quota_rescan_status(fs_info, argp);
4886  	case BTRFS_IOC_QUOTA_RESCAN_WAIT:
4887  		return btrfs_ioctl_quota_rescan_wait(fs_info, argp);
4888  	case BTRFS_IOC_DEV_REPLACE:
4889  		return btrfs_ioctl_dev_replace(fs_info, argp);
4890  	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
4891  		return btrfs_ioctl_get_supported_features(argp);
4892  	case BTRFS_IOC_GET_FEATURES:
4893  		return btrfs_ioctl_get_features(fs_info, argp);
4894  	case BTRFS_IOC_SET_FEATURES:
4895  		return btrfs_ioctl_set_features(file, argp);
4896  	case FS_IOC_FSGETXATTR:
4897  		return btrfs_ioctl_fsgetxattr(file, argp);
4898  	case FS_IOC_FSSETXATTR:
4899  		return btrfs_ioctl_fssetxattr(file, argp);
4900  	case BTRFS_IOC_GET_SUBVOL_INFO:
4901  		return btrfs_ioctl_get_subvol_info(file, argp);
4902  	case BTRFS_IOC_GET_SUBVOL_ROOTREF:
4903  		return btrfs_ioctl_get_subvol_rootref(file, argp);
4904  	case BTRFS_IOC_INO_LOOKUP_USER:
4905  		return btrfs_ioctl_ino_lookup_user(file, argp);
4906  	}
4907  
4908  	return -ENOTTY;
4909  }
4910  
4911  #ifdef CONFIG_COMPAT
4912  long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4913  {
4914  	/*
4915  	 * These all access 32-bit values anyway so no further
4916  	 * handling is necessary.
4917  	 */
4918  	switch (cmd) {
4919  	case FS_IOC32_GETFLAGS:
4920  		cmd = FS_IOC_GETFLAGS;
4921  		break;
4922  	case FS_IOC32_SETFLAGS:
4923  		cmd = FS_IOC_SETFLAGS;
4924  		break;
4925  	case FS_IOC32_GETVERSION:
4926  		cmd = FS_IOC_GETVERSION;
4927  		break;
4928  	}
4929  
4930  	return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
4931  }
4932  #endif
4933