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TOMOYO Linux Cross Reference
Linux/fs/btrfs/ioctl.c

Version: ~ [ linux-5.11 ] ~ [ linux-5.10.17 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.99 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.176 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.221 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.257 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.257 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * Copyright (C) 2007 Oracle.  All rights reserved.
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of the GNU General Public
  6  * License v2 as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 11  * General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public
 14  * License along with this program; if not, write to the
 15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 16  * Boston, MA 021110-1307, USA.
 17  */
 18 
 19 #include <linux/kernel.h>
 20 #include <linux/bio.h>
 21 #include <linux/buffer_head.h>
 22 #include <linux/file.h>
 23 #include <linux/fs.h>
 24 #include <linux/fsnotify.h>
 25 #include <linux/pagemap.h>
 26 #include <linux/highmem.h>
 27 #include <linux/time.h>
 28 #include <linux/init.h>
 29 #include <linux/string.h>
 30 #include <linux/backing-dev.h>
 31 #include <linux/mount.h>
 32 #include <linux/mpage.h>
 33 #include <linux/namei.h>
 34 #include <linux/swap.h>
 35 #include <linux/writeback.h>
 36 #include <linux/statfs.h>
 37 #include <linux/compat.h>
 38 #include <linux/bit_spinlock.h>
 39 #include <linux/security.h>
 40 #include <linux/xattr.h>
 41 #include <linux/vmalloc.h>
 42 #include <linux/slab.h>
 43 #include <linux/blkdev.h>
 44 #include <linux/uuid.h>
 45 #include <linux/btrfs.h>
 46 #include <linux/uaccess.h>
 47 #include "ctree.h"
 48 #include "disk-io.h"
 49 #include "transaction.h"
 50 #include "btrfs_inode.h"
 51 #include "print-tree.h"
 52 #include "volumes.h"
 53 #include "locking.h"
 54 #include "inode-map.h"
 55 #include "backref.h"
 56 #include "rcu-string.h"
 57 #include "send.h"
 58 #include "dev-replace.h"
 59 #include "props.h"
 60 #include "sysfs.h"
 61 
 62 #ifdef CONFIG_64BIT
 63 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
 64  * structures are incorrect, as the timespec structure from userspace
 65  * is 4 bytes too small. We define these alternatives here to teach
 66  * the kernel about the 32-bit struct packing.
 67  */
 68 struct btrfs_ioctl_timespec_32 {
 69         __u64 sec;
 70         __u32 nsec;
 71 } __attribute__ ((__packed__));
 72 
 73 struct btrfs_ioctl_received_subvol_args_32 {
 74         char    uuid[BTRFS_UUID_SIZE];  /* in */
 75         __u64   stransid;               /* in */
 76         __u64   rtransid;               /* out */
 77         struct btrfs_ioctl_timespec_32 stime; /* in */
 78         struct btrfs_ioctl_timespec_32 rtime; /* out */
 79         __u64   flags;                  /* in */
 80         __u64   reserved[16];           /* in */
 81 } __attribute__ ((__packed__));
 82 
 83 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
 84                                 struct btrfs_ioctl_received_subvol_args_32)
 85 #endif
 86 
 87 
 88 static int btrfs_clone(struct inode *src, struct inode *inode,
 89                        u64 off, u64 olen, u64 olen_aligned, u64 destoff);
 90 
 91 /* Mask out flags that are inappropriate for the given type of inode. */
 92 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
 93 {
 94         if (S_ISDIR(mode))
 95                 return flags;
 96         else if (S_ISREG(mode))
 97                 return flags & ~FS_DIRSYNC_FL;
 98         else
 99                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
100 }
101 
102 /*
103  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
104  */
105 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
106 {
107         unsigned int iflags = 0;
108 
109         if (flags & BTRFS_INODE_SYNC)
110                 iflags |= FS_SYNC_FL;
111         if (flags & BTRFS_INODE_IMMUTABLE)
112                 iflags |= FS_IMMUTABLE_FL;
113         if (flags & BTRFS_INODE_APPEND)
114                 iflags |= FS_APPEND_FL;
115         if (flags & BTRFS_INODE_NODUMP)
116                 iflags |= FS_NODUMP_FL;
117         if (flags & BTRFS_INODE_NOATIME)
118                 iflags |= FS_NOATIME_FL;
119         if (flags & BTRFS_INODE_DIRSYNC)
120                 iflags |= FS_DIRSYNC_FL;
121         if (flags & BTRFS_INODE_NODATACOW)
122                 iflags |= FS_NOCOW_FL;
123 
124         if ((flags & BTRFS_INODE_COMPRESS) && !(flags & BTRFS_INODE_NOCOMPRESS))
125                 iflags |= FS_COMPR_FL;
126         else if (flags & BTRFS_INODE_NOCOMPRESS)
127                 iflags |= FS_NOCOMP_FL;
128 
129         return iflags;
130 }
131 
132 /*
133  * Update inode->i_flags based on the btrfs internal flags.
134  */
135 void btrfs_update_iflags(struct inode *inode)
136 {
137         struct btrfs_inode *ip = BTRFS_I(inode);
138 
139         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
140 
141         if (ip->flags & BTRFS_INODE_SYNC)
142                 inode->i_flags |= S_SYNC;
143         if (ip->flags & BTRFS_INODE_IMMUTABLE)
144                 inode->i_flags |= S_IMMUTABLE;
145         if (ip->flags & BTRFS_INODE_APPEND)
146                 inode->i_flags |= S_APPEND;
147         if (ip->flags & BTRFS_INODE_NOATIME)
148                 inode->i_flags |= S_NOATIME;
149         if (ip->flags & BTRFS_INODE_DIRSYNC)
150                 inode->i_flags |= S_DIRSYNC;
151 }
152 
153 /*
154  * Inherit flags from the parent inode.
155  *
156  * Currently only the compression flags and the cow flags are inherited.
157  */
158 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
159 {
160         unsigned int flags;
161 
162         if (!dir)
163                 return;
164 
165         flags = BTRFS_I(dir)->flags;
166 
167         if (flags & BTRFS_INODE_NOCOMPRESS) {
168                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
169                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
170         } else if (flags & BTRFS_INODE_COMPRESS) {
171                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
172                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
173         }
174 
175         if (flags & BTRFS_INODE_NODATACOW) {
176                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
177                 if (S_ISREG(inode->i_mode))
178                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
179         }
180 
181         btrfs_update_iflags(inode);
182 }
183 
184 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
185 {
186         struct btrfs_inode *ip = BTRFS_I(file_inode(file));
187         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
188 
189         if (copy_to_user(arg, &flags, sizeof(flags)))
190                 return -EFAULT;
191         return 0;
192 }
193 
194 static int check_flags(unsigned int flags)
195 {
196         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
197                       FS_NOATIME_FL | FS_NODUMP_FL | \
198                       FS_SYNC_FL | FS_DIRSYNC_FL | \
199                       FS_NOCOMP_FL | FS_COMPR_FL |
200                       FS_NOCOW_FL))
201                 return -EOPNOTSUPP;
202 
203         if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
204                 return -EINVAL;
205 
206         return 0;
207 }
208 
209 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
210 {
211         struct inode *inode = file_inode(file);
212         struct btrfs_inode *ip = BTRFS_I(inode);
213         struct btrfs_root *root = ip->root;
214         struct btrfs_trans_handle *trans;
215         unsigned int flags, oldflags;
216         int ret;
217         u64 ip_oldflags;
218         unsigned int i_oldflags;
219         umode_t mode;
220 
221         if (!inode_owner_or_capable(inode))
222                 return -EPERM;
223 
224         if (btrfs_root_readonly(root))
225                 return -EROFS;
226 
227         if (copy_from_user(&flags, arg, sizeof(flags)))
228                 return -EFAULT;
229 
230         ret = check_flags(flags);
231         if (ret)
232                 return ret;
233 
234         ret = mnt_want_write_file(file);
235         if (ret)
236                 return ret;
237 
238         mutex_lock(&inode->i_mutex);
239 
240         ip_oldflags = ip->flags;
241         i_oldflags = inode->i_flags;
242         mode = inode->i_mode;
243 
244         flags = btrfs_mask_flags(inode->i_mode, flags);
245         oldflags = btrfs_flags_to_ioctl(ip->flags);
246         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
247                 if (!capable(CAP_LINUX_IMMUTABLE)) {
248                         ret = -EPERM;
249                         goto out_unlock;
250                 }
251         }
252 
253         if (flags & FS_SYNC_FL)
254                 ip->flags |= BTRFS_INODE_SYNC;
255         else
256                 ip->flags &= ~BTRFS_INODE_SYNC;
257         if (flags & FS_IMMUTABLE_FL)
258                 ip->flags |= BTRFS_INODE_IMMUTABLE;
259         else
260                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
261         if (flags & FS_APPEND_FL)
262                 ip->flags |= BTRFS_INODE_APPEND;
263         else
264                 ip->flags &= ~BTRFS_INODE_APPEND;
265         if (flags & FS_NODUMP_FL)
266                 ip->flags |= BTRFS_INODE_NODUMP;
267         else
268                 ip->flags &= ~BTRFS_INODE_NODUMP;
269         if (flags & FS_NOATIME_FL)
270                 ip->flags |= BTRFS_INODE_NOATIME;
271         else
272                 ip->flags &= ~BTRFS_INODE_NOATIME;
273         if (flags & FS_DIRSYNC_FL)
274                 ip->flags |= BTRFS_INODE_DIRSYNC;
275         else
276                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
277         if (flags & FS_NOCOW_FL) {
278                 if (S_ISREG(mode)) {
279                         /*
280                          * It's safe to turn csums off here, no extents exist.
281                          * Otherwise we want the flag to reflect the real COW
282                          * status of the file and will not set it.
283                          */
284                         if (inode->i_size == 0)
285                                 ip->flags |= BTRFS_INODE_NODATACOW
286                                            | BTRFS_INODE_NODATASUM;
287                 } else {
288                         ip->flags |= BTRFS_INODE_NODATACOW;
289                 }
290         } else {
291                 /*
292                  * Revert back under same assuptions as above
293                  */
294                 if (S_ISREG(mode)) {
295                         if (inode->i_size == 0)
296                                 ip->flags &= ~(BTRFS_INODE_NODATACOW
297                                              | BTRFS_INODE_NODATASUM);
298                 } else {
299                         ip->flags &= ~BTRFS_INODE_NODATACOW;
300                 }
301         }
302 
303         /*
304          * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
305          * flag may be changed automatically if compression code won't make
306          * things smaller.
307          */
308         if (flags & FS_NOCOMP_FL) {
309                 ip->flags &= ~BTRFS_INODE_COMPRESS;
310                 ip->flags |= BTRFS_INODE_NOCOMPRESS;
311 
312                 ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
313                 if (ret && ret != -ENODATA)
314                         goto out_drop;
315         } else if (flags & FS_COMPR_FL) {
316                 const char *comp;
317 
318                 ip->flags |= BTRFS_INODE_COMPRESS;
319                 ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
320 
321                 if (root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
322                         comp = "lzo";
323                 else
324                         comp = "zlib";
325                 ret = btrfs_set_prop(inode, "btrfs.compression",
326                                      comp, strlen(comp), 0);
327                 if (ret)
328                         goto out_drop;
329 
330         } else {
331                 ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
332         }
333 
334         trans = btrfs_start_transaction(root, 1);
335         if (IS_ERR(trans)) {
336                 ret = PTR_ERR(trans);
337                 goto out_drop;
338         }
339 
340         btrfs_update_iflags(inode);
341         inode_inc_iversion(inode);
342         inode->i_ctime = CURRENT_TIME;
343         ret = btrfs_update_inode(trans, root, inode);
344 
345         btrfs_end_transaction(trans, root);
346  out_drop:
347         if (ret) {
348                 ip->flags = ip_oldflags;
349                 inode->i_flags = i_oldflags;
350         }
351 
352  out_unlock:
353         mutex_unlock(&inode->i_mutex);
354         mnt_drop_write_file(file);
355         return ret;
356 }
357 
358 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
359 {
360         struct inode *inode = file_inode(file);
361 
362         return put_user(inode->i_generation, arg);
363 }
364 
365 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
366 {
367         struct btrfs_fs_info *fs_info = btrfs_sb(file_inode(file)->i_sb);
368         struct btrfs_device *device;
369         struct request_queue *q;
370         struct fstrim_range range;
371         u64 minlen = ULLONG_MAX;
372         u64 num_devices = 0;
373         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
374         int ret;
375 
376         if (!capable(CAP_SYS_ADMIN))
377                 return -EPERM;
378 
379         rcu_read_lock();
380         list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
381                                 dev_list) {
382                 if (!device->bdev)
383                         continue;
384                 q = bdev_get_queue(device->bdev);
385                 if (blk_queue_discard(q)) {
386                         num_devices++;
387                         minlen = min((u64)q->limits.discard_granularity,
388                                      minlen);
389                 }
390         }
391         rcu_read_unlock();
392 
393         if (!num_devices)
394                 return -EOPNOTSUPP;
395         if (copy_from_user(&range, arg, sizeof(range)))
396                 return -EFAULT;
397         if (range.start > total_bytes ||
398             range.len < fs_info->sb->s_blocksize)
399                 return -EINVAL;
400 
401         range.len = min(range.len, total_bytes - range.start);
402         range.minlen = max(range.minlen, minlen);
403         ret = btrfs_trim_fs(fs_info->tree_root, &range);
404         if (ret < 0)
405                 return ret;
406 
407         if (copy_to_user(arg, &range, sizeof(range)))
408                 return -EFAULT;
409 
410         return 0;
411 }
412 
413 int btrfs_is_empty_uuid(u8 *uuid)
414 {
415         int i;
416 
417         for (i = 0; i < BTRFS_UUID_SIZE; i++) {
418                 if (uuid[i])
419                         return 0;
420         }
421         return 1;
422 }
423 
424 static noinline int create_subvol(struct inode *dir,
425                                   struct dentry *dentry,
426                                   char *name, int namelen,
427                                   u64 *async_transid,
428                                   struct btrfs_qgroup_inherit *inherit)
429 {
430         struct btrfs_trans_handle *trans;
431         struct btrfs_key key;
432         struct btrfs_root_item root_item;
433         struct btrfs_inode_item *inode_item;
434         struct extent_buffer *leaf;
435         struct btrfs_root *root = BTRFS_I(dir)->root;
436         struct btrfs_root *new_root;
437         struct btrfs_block_rsv block_rsv;
438         struct timespec cur_time = CURRENT_TIME;
439         struct inode *inode;
440         int ret;
441         int err;
442         u64 objectid;
443         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
444         u64 index = 0;
445         u64 qgroup_reserved;
446         uuid_le new_uuid;
447 
448         ret = btrfs_find_free_objectid(root->fs_info->tree_root, &objectid);
449         if (ret)
450                 return ret;
451 
452         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
453         /*
454          * The same as the snapshot creation, please see the comment
455          * of create_snapshot().
456          */
457         ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
458                                                8, &qgroup_reserved, false);
459         if (ret)
460                 return ret;
461 
462         trans = btrfs_start_transaction(root, 0);
463         if (IS_ERR(trans)) {
464                 ret = PTR_ERR(trans);
465                 btrfs_subvolume_release_metadata(root, &block_rsv,
466                                                  qgroup_reserved);
467                 return ret;
468         }
469         trans->block_rsv = &block_rsv;
470         trans->bytes_reserved = block_rsv.size;
471 
472         ret = btrfs_qgroup_inherit(trans, root->fs_info, 0, objectid, inherit);
473         if (ret)
474                 goto fail;
475 
476         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
477                                       0, objectid, NULL, 0, 0, 0);
478         if (IS_ERR(leaf)) {
479                 ret = PTR_ERR(leaf);
480                 goto fail;
481         }
482 
483         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
484         btrfs_set_header_bytenr(leaf, leaf->start);
485         btrfs_set_header_generation(leaf, trans->transid);
486         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
487         btrfs_set_header_owner(leaf, objectid);
488 
489         write_extent_buffer(leaf, root->fs_info->fsid, btrfs_header_fsid(),
490                             BTRFS_FSID_SIZE);
491         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
492                             btrfs_header_chunk_tree_uuid(leaf),
493                             BTRFS_UUID_SIZE);
494         btrfs_mark_buffer_dirty(leaf);
495 
496         memset(&root_item, 0, sizeof(root_item));
497 
498         inode_item = &root_item.inode;
499         btrfs_set_stack_inode_generation(inode_item, 1);
500         btrfs_set_stack_inode_size(inode_item, 3);
501         btrfs_set_stack_inode_nlink(inode_item, 1);
502         btrfs_set_stack_inode_nbytes(inode_item, root->leafsize);
503         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
504 
505         btrfs_set_root_flags(&root_item, 0);
506         btrfs_set_root_limit(&root_item, 0);
507         btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
508 
509         btrfs_set_root_bytenr(&root_item, leaf->start);
510         btrfs_set_root_generation(&root_item, trans->transid);
511         btrfs_set_root_level(&root_item, 0);
512         btrfs_set_root_refs(&root_item, 1);
513         btrfs_set_root_used(&root_item, leaf->len);
514         btrfs_set_root_last_snapshot(&root_item, 0);
515 
516         btrfs_set_root_generation_v2(&root_item,
517                         btrfs_root_generation(&root_item));
518         uuid_le_gen(&new_uuid);
519         memcpy(root_item.uuid, new_uuid.b, BTRFS_UUID_SIZE);
520         btrfs_set_stack_timespec_sec(&root_item.otime, cur_time.tv_sec);
521         btrfs_set_stack_timespec_nsec(&root_item.otime, cur_time.tv_nsec);
522         root_item.ctime = root_item.otime;
523         btrfs_set_root_ctransid(&root_item, trans->transid);
524         btrfs_set_root_otransid(&root_item, trans->transid);
525 
526         btrfs_tree_unlock(leaf);
527         free_extent_buffer(leaf);
528         leaf = NULL;
529 
530         btrfs_set_root_dirid(&root_item, new_dirid);
531 
532         key.objectid = objectid;
533         key.offset = 0;
534         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
535         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
536                                 &root_item);
537         if (ret)
538                 goto fail;
539 
540         key.offset = (u64)-1;
541         new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
542         if (IS_ERR(new_root)) {
543                 btrfs_abort_transaction(trans, root, PTR_ERR(new_root));
544                 ret = PTR_ERR(new_root);
545                 goto fail;
546         }
547 
548         btrfs_record_root_in_trans(trans, new_root);
549 
550         ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
551         if (ret) {
552                 /* We potentially lose an unused inode item here */
553                 btrfs_abort_transaction(trans, root, ret);
554                 goto fail;
555         }
556 
557         /*
558          * insert the directory item
559          */
560         ret = btrfs_set_inode_index(dir, &index);
561         if (ret) {
562                 btrfs_abort_transaction(trans, root, ret);
563                 goto fail;
564         }
565 
566         ret = btrfs_insert_dir_item(trans, root,
567                                     name, namelen, dir, &key,
568                                     BTRFS_FT_DIR, index);
569         if (ret) {
570                 btrfs_abort_transaction(trans, root, ret);
571                 goto fail;
572         }
573 
574         btrfs_i_size_write(dir, dir->i_size + namelen * 2);
575         ret = btrfs_update_inode(trans, root, dir);
576         BUG_ON(ret);
577 
578         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
579                                  objectid, root->root_key.objectid,
580                                  btrfs_ino(dir), index, name, namelen);
581         BUG_ON(ret);
582 
583         ret = btrfs_uuid_tree_add(trans, root->fs_info->uuid_root,
584                                   root_item.uuid, BTRFS_UUID_KEY_SUBVOL,
585                                   objectid);
586         if (ret)
587                 btrfs_abort_transaction(trans, root, ret);
588 
589 fail:
590         trans->block_rsv = NULL;
591         trans->bytes_reserved = 0;
592         btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
593 
594         if (async_transid) {
595                 *async_transid = trans->transid;
596                 err = btrfs_commit_transaction_async(trans, root, 1);
597                 if (err)
598                         err = btrfs_commit_transaction(trans, root);
599         } else {
600                 err = btrfs_commit_transaction(trans, root);
601         }
602         if (err && !ret)
603                 ret = err;
604 
605         if (!ret) {
606                 inode = btrfs_lookup_dentry(dir, dentry);
607                 if (IS_ERR(inode))
608                         return PTR_ERR(inode);
609                 d_instantiate(dentry, inode);
610         }
611         return ret;
612 }
613 
614 static void btrfs_wait_nocow_write(struct btrfs_root *root)
615 {
616         s64 writers;
617         DEFINE_WAIT(wait);
618 
619         do {
620                 prepare_to_wait(&root->subv_writers->wait, &wait,
621                                 TASK_UNINTERRUPTIBLE);
622 
623                 writers = percpu_counter_sum(&root->subv_writers->counter);
624                 if (writers)
625                         schedule();
626 
627                 finish_wait(&root->subv_writers->wait, &wait);
628         } while (writers);
629 }
630 
631 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
632                            struct dentry *dentry, char *name, int namelen,
633                            u64 *async_transid, bool readonly,
634                            struct btrfs_qgroup_inherit *inherit)
635 {
636         struct inode *inode;
637         struct btrfs_pending_snapshot *pending_snapshot;
638         struct btrfs_trans_handle *trans;
639         int ret;
640 
641         if (!root->ref_cows)
642                 return -EINVAL;
643 
644         atomic_inc(&root->will_be_snapshoted);
645         smp_mb__after_atomic_inc();
646         btrfs_wait_nocow_write(root);
647 
648         ret = btrfs_start_delalloc_inodes(root, 0);
649         if (ret)
650                 goto out;
651 
652         btrfs_wait_ordered_extents(root, -1);
653 
654         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
655         if (!pending_snapshot) {
656                 ret = -ENOMEM;
657                 goto out;
658         }
659 
660         btrfs_init_block_rsv(&pending_snapshot->block_rsv,
661                              BTRFS_BLOCK_RSV_TEMP);
662         /*
663          * 1 - parent dir inode
664          * 2 - dir entries
665          * 1 - root item
666          * 2 - root ref/backref
667          * 1 - root of snapshot
668          * 1 - UUID item
669          */
670         ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
671                                         &pending_snapshot->block_rsv, 8,
672                                         &pending_snapshot->qgroup_reserved,
673                                         false);
674         if (ret)
675                 goto free;
676 
677         pending_snapshot->dentry = dentry;
678         pending_snapshot->root = root;
679         pending_snapshot->readonly = readonly;
680         pending_snapshot->dir = dir;
681         pending_snapshot->inherit = inherit;
682 
683         trans = btrfs_start_transaction(root, 0);
684         if (IS_ERR(trans)) {
685                 ret = PTR_ERR(trans);
686                 goto fail;
687         }
688 
689         spin_lock(&root->fs_info->trans_lock);
690         list_add(&pending_snapshot->list,
691                  &trans->transaction->pending_snapshots);
692         spin_unlock(&root->fs_info->trans_lock);
693         if (async_transid) {
694                 *async_transid = trans->transid;
695                 ret = btrfs_commit_transaction_async(trans,
696                                      root->fs_info->extent_root, 1);
697                 if (ret)
698                         ret = btrfs_commit_transaction(trans, root);
699         } else {
700                 ret = btrfs_commit_transaction(trans,
701                                                root->fs_info->extent_root);
702         }
703         if (ret)
704                 goto fail;
705 
706         ret = pending_snapshot->error;
707         if (ret)
708                 goto fail;
709 
710         ret = btrfs_orphan_cleanup(pending_snapshot->snap);
711         if (ret)
712                 goto fail;
713 
714         inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
715         if (IS_ERR(inode)) {
716                 ret = PTR_ERR(inode);
717                 goto fail;
718         }
719 
720         d_instantiate(dentry, inode);
721         ret = 0;
722 fail:
723         btrfs_subvolume_release_metadata(BTRFS_I(dir)->root,
724                                          &pending_snapshot->block_rsv,
725                                          pending_snapshot->qgroup_reserved);
726 free:
727         kfree(pending_snapshot);
728 out:
729         atomic_dec(&root->will_be_snapshoted);
730         return ret;
731 }
732 
733 /*  copy of check_sticky in fs/namei.c()
734 * It's inline, so penalty for filesystems that don't use sticky bit is
735 * minimal.
736 */
737 static inline int btrfs_check_sticky(struct inode *dir, struct inode *inode)
738 {
739         kuid_t fsuid = current_fsuid();
740 
741         if (!(dir->i_mode & S_ISVTX))
742                 return 0;
743         if (uid_eq(inode->i_uid, fsuid))
744                 return 0;
745         if (uid_eq(dir->i_uid, fsuid))
746                 return 0;
747         return !capable(CAP_FOWNER);
748 }
749 
750 /*  copy of may_delete in fs/namei.c()
751  *      Check whether we can remove a link victim from directory dir, check
752  *  whether the type of victim is right.
753  *  1. We can't do it if dir is read-only (done in permission())
754  *  2. We should have write and exec permissions on dir
755  *  3. We can't remove anything from append-only dir
756  *  4. We can't do anything with immutable dir (done in permission())
757  *  5. If the sticky bit on dir is set we should either
758  *      a. be owner of dir, or
759  *      b. be owner of victim, or
760  *      c. have CAP_FOWNER capability
761  *  6. If the victim is append-only or immutable we can't do antyhing with
762  *     links pointing to it.
763  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
764  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
765  *  9. We can't remove a root or mountpoint.
766  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
767  *     nfs_async_unlink().
768  */
769 
770 static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
771 {
772         int error;
773 
774         if (!victim->d_inode)
775                 return -ENOENT;
776 
777         BUG_ON(victim->d_parent->d_inode != dir);
778         audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
779 
780         error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
781         if (error)
782                 return error;
783         if (IS_APPEND(dir))
784                 return -EPERM;
785         if (btrfs_check_sticky(dir, victim->d_inode)||
786                 IS_APPEND(victim->d_inode)||
787             IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))
788                 return -EPERM;
789         if (isdir) {
790                 if (!S_ISDIR(victim->d_inode->i_mode))
791                         return -ENOTDIR;
792                 if (IS_ROOT(victim))
793                         return -EBUSY;
794         } else if (S_ISDIR(victim->d_inode->i_mode))
795                 return -EISDIR;
796         if (IS_DEADDIR(dir))
797                 return -ENOENT;
798         if (victim->d_flags & DCACHE_NFSFS_RENAMED)
799                 return -EBUSY;
800         return 0;
801 }
802 
803 /* copy of may_create in fs/namei.c() */
804 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
805 {
806         if (child->d_inode)
807                 return -EEXIST;
808         if (IS_DEADDIR(dir))
809                 return -ENOENT;
810         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
811 }
812 
813 /*
814  * Create a new subvolume below @parent.  This is largely modeled after
815  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
816  * inside this filesystem so it's quite a bit simpler.
817  */
818 static noinline int btrfs_mksubvol(struct path *parent,
819                                    char *name, int namelen,
820                                    struct btrfs_root *snap_src,
821                                    u64 *async_transid, bool readonly,
822                                    struct btrfs_qgroup_inherit *inherit)
823 {
824         struct inode *dir  = parent->dentry->d_inode;
825         struct dentry *dentry;
826         int error;
827 
828         error = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT);
829         if (error == -EINTR)
830                 return error;
831 
832         dentry = lookup_one_len(name, parent->dentry, namelen);
833         error = PTR_ERR(dentry);
834         if (IS_ERR(dentry))
835                 goto out_unlock;
836 
837         error = -EEXIST;
838         if (dentry->d_inode)
839                 goto out_dput;
840 
841         error = btrfs_may_create(dir, dentry);
842         if (error)
843                 goto out_dput;
844 
845         /*
846          * even if this name doesn't exist, we may get hash collisions.
847          * check for them now when we can safely fail
848          */
849         error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
850                                                dir->i_ino, name,
851                                                namelen);
852         if (error)
853                 goto out_dput;
854 
855         down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
856 
857         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
858                 goto out_up_read;
859 
860         if (snap_src) {
861                 error = create_snapshot(snap_src, dir, dentry, name, namelen,
862                                         async_transid, readonly, inherit);
863         } else {
864                 error = create_subvol(dir, dentry, name, namelen,
865                                       async_transid, inherit);
866         }
867         if (!error)
868                 fsnotify_mkdir(dir, dentry);
869 out_up_read:
870         up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
871 out_dput:
872         dput(dentry);
873 out_unlock:
874         mutex_unlock(&dir->i_mutex);
875         return error;
876 }
877 
878 /*
879  * When we're defragging a range, we don't want to kick it off again
880  * if it is really just waiting for delalloc to send it down.
881  * If we find a nice big extent or delalloc range for the bytes in the
882  * file you want to defrag, we return 0 to let you know to skip this
883  * part of the file
884  */
885 static int check_defrag_in_cache(struct inode *inode, u64 offset, int thresh)
886 {
887         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
888         struct extent_map *em = NULL;
889         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
890         u64 end;
891 
892         read_lock(&em_tree->lock);
893         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
894         read_unlock(&em_tree->lock);
895 
896         if (em) {
897                 end = extent_map_end(em);
898                 free_extent_map(em);
899                 if (end - offset > thresh)
900                         return 0;
901         }
902         /* if we already have a nice delalloc here, just stop */
903         thresh /= 2;
904         end = count_range_bits(io_tree, &offset, offset + thresh,
905                                thresh, EXTENT_DELALLOC, 1);
906         if (end >= thresh)
907                 return 0;
908         return 1;
909 }
910 
911 /*
912  * helper function to walk through a file and find extents
913  * newer than a specific transid, and smaller than thresh.
914  *
915  * This is used by the defragging code to find new and small
916  * extents
917  */
918 static int find_new_extents(struct btrfs_root *root,
919                             struct inode *inode, u64 newer_than,
920                             u64 *off, int thresh)
921 {
922         struct btrfs_path *path;
923         struct btrfs_key min_key;
924         struct extent_buffer *leaf;
925         struct btrfs_file_extent_item *extent;
926         int type;
927         int ret;
928         u64 ino = btrfs_ino(inode);
929 
930         path = btrfs_alloc_path();
931         if (!path)
932                 return -ENOMEM;
933 
934         min_key.objectid = ino;
935         min_key.type = BTRFS_EXTENT_DATA_KEY;
936         min_key.offset = *off;
937 
938         while (1) {
939                 path->keep_locks = 1;
940                 ret = btrfs_search_forward(root, &min_key, path, newer_than);
941                 if (ret != 0)
942                         goto none;
943                 path->keep_locks = 0;
944                 btrfs_unlock_up_safe(path, 1);
945 process_slot:
946                 if (min_key.objectid != ino)
947                         goto none;
948                 if (min_key.type != BTRFS_EXTENT_DATA_KEY)
949                         goto none;
950 
951                 leaf = path->nodes[0];
952                 extent = btrfs_item_ptr(leaf, path->slots[0],
953                                         struct btrfs_file_extent_item);
954 
955                 type = btrfs_file_extent_type(leaf, extent);
956                 if (type == BTRFS_FILE_EXTENT_REG &&
957                     btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
958                     check_defrag_in_cache(inode, min_key.offset, thresh)) {
959                         *off = min_key.offset;
960                         btrfs_free_path(path);
961                         return 0;
962                 }
963 
964                 path->slots[0]++;
965                 if (path->slots[0] < btrfs_header_nritems(leaf)) {
966                         btrfs_item_key_to_cpu(leaf, &min_key, path->slots[0]);
967                         goto process_slot;
968                 }
969 
970                 if (min_key.offset == (u64)-1)
971                         goto none;
972 
973                 min_key.offset++;
974                 btrfs_release_path(path);
975         }
976 none:
977         btrfs_free_path(path);
978         return -ENOENT;
979 }
980 
981 static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start)
982 {
983         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
984         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
985         struct extent_map *em;
986         u64 len = PAGE_CACHE_SIZE;
987 
988         /*
989          * hopefully we have this extent in the tree already, try without
990          * the full extent lock
991          */
992         read_lock(&em_tree->lock);
993         em = lookup_extent_mapping(em_tree, start, len);
994         read_unlock(&em_tree->lock);
995 
996         if (!em) {
997                 struct extent_state *cached = NULL;
998                 u64 end = start + len - 1;
999 
1000                 /* get the big lock and read metadata off disk */
1001                 lock_extent_bits(io_tree, start, end, 0, &cached);
1002                 em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
1003                 unlock_extent_cached(io_tree, start, end, &cached, GFP_NOFS);
1004 
1005                 if (IS_ERR(em))
1006                         return NULL;
1007         }
1008 
1009         return em;
1010 }
1011 
1012 static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
1013 {
1014         struct extent_map *next;
1015         bool ret = true;
1016 
1017         /* this is the last extent */
1018         if (em->start + em->len >= i_size_read(inode))
1019                 return false;
1020 
1021         next = defrag_lookup_extent(inode, em->start + em->len);
1022         if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE ||
1023             (em->block_start + em->block_len == next->block_start))
1024                 ret = false;
1025 
1026         free_extent_map(next);
1027         return ret;
1028 }
1029 
1030 static int should_defrag_range(struct inode *inode, u64 start, int thresh,
1031                                u64 *last_len, u64 *skip, u64 *defrag_end,
1032                                int compress)
1033 {
1034         struct extent_map *em;
1035         int ret = 1;
1036         bool next_mergeable = true;
1037 
1038         /*
1039          * make sure that once we start defragging an extent, we keep on
1040          * defragging it
1041          */
1042         if (start < *defrag_end)
1043                 return 1;
1044 
1045         *skip = 0;
1046 
1047         em = defrag_lookup_extent(inode, start);
1048         if (!em)
1049                 return 0;
1050 
1051         /* this will cover holes, and inline extents */
1052         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1053                 ret = 0;
1054                 goto out;
1055         }
1056 
1057         next_mergeable = defrag_check_next_extent(inode, em);
1058 
1059         /*
1060          * we hit a real extent, if it is big or the next extent is not a
1061          * real extent, don't bother defragging it
1062          */
1063         if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1064             (em->len >= thresh || !next_mergeable))
1065                 ret = 0;
1066 out:
1067         /*
1068          * last_len ends up being a counter of how many bytes we've defragged.
1069          * every time we choose not to defrag an extent, we reset *last_len
1070          * so that the next tiny extent will force a defrag.
1071          *
1072          * The end result of this is that tiny extents before a single big
1073          * extent will force at least part of that big extent to be defragged.
1074          */
1075         if (ret) {
1076                 *defrag_end = extent_map_end(em);
1077         } else {
1078                 *last_len = 0;
1079                 *skip = extent_map_end(em);
1080                 *defrag_end = 0;
1081         }
1082 
1083         free_extent_map(em);
1084         return ret;
1085 }
1086 
1087 /*
1088  * it doesn't do much good to defrag one or two pages
1089  * at a time.  This pulls in a nice chunk of pages
1090  * to COW and defrag.
1091  *
1092  * It also makes sure the delalloc code has enough
1093  * dirty data to avoid making new small extents as part
1094  * of the defrag
1095  *
1096  * It's a good idea to start RA on this range
1097  * before calling this.
1098  */
1099 static int cluster_pages_for_defrag(struct inode *inode,
1100                                     struct page **pages,
1101                                     unsigned long start_index,
1102                                     unsigned long num_pages)
1103 {
1104         unsigned long file_end;
1105         u64 isize = i_size_read(inode);
1106         u64 page_start;
1107         u64 page_end;
1108         u64 page_cnt;
1109         int ret;
1110         int i;
1111         int i_done;
1112         struct btrfs_ordered_extent *ordered;
1113         struct extent_state *cached_state = NULL;
1114         struct extent_io_tree *tree;
1115         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1116 
1117         file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
1118         if (!isize || start_index > file_end)
1119                 return 0;
1120 
1121         page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1122 
1123         ret = btrfs_delalloc_reserve_space(inode,
1124                                            page_cnt << PAGE_CACHE_SHIFT);
1125         if (ret)
1126                 return ret;
1127         i_done = 0;
1128         tree = &BTRFS_I(inode)->io_tree;
1129 
1130         /* step one, lock all the pages */
1131         for (i = 0; i < page_cnt; i++) {
1132                 struct page *page;
1133 again:
1134                 page = find_or_create_page(inode->i_mapping,
1135                                            start_index + i, mask);
1136                 if (!page)
1137                         break;
1138 
1139                 page_start = page_offset(page);
1140                 page_end = page_start + PAGE_CACHE_SIZE - 1;
1141                 while (1) {
1142                         lock_extent_bits(tree, page_start, page_end,
1143                                          0, &cached_state);
1144                         ordered = btrfs_lookup_ordered_extent(inode,
1145                                                               page_start);
1146                         unlock_extent_cached(tree, page_start, page_end,
1147                                              &cached_state, GFP_NOFS);
1148                         if (!ordered)
1149                                 break;
1150 
1151                         unlock_page(page);
1152                         btrfs_start_ordered_extent(inode, ordered, 1);
1153                         btrfs_put_ordered_extent(ordered);
1154                         lock_page(page);
1155                         /*
1156                          * we unlocked the page above, so we need check if
1157                          * it was released or not.
1158                          */
1159                         if (page->mapping != inode->i_mapping) {
1160                                 unlock_page(page);
1161                                 page_cache_release(page);
1162                                 goto again;
1163                         }
1164                 }
1165 
1166                 if (!PageUptodate(page)) {
1167                         btrfs_readpage(NULL, page);
1168                         lock_page(page);
1169                         if (!PageUptodate(page)) {
1170                                 unlock_page(page);
1171                                 page_cache_release(page);
1172                                 ret = -EIO;
1173                                 break;
1174                         }
1175                 }
1176 
1177                 if (page->mapping != inode->i_mapping) {
1178                         unlock_page(page);
1179                         page_cache_release(page);
1180                         goto again;
1181                 }
1182 
1183                 pages[i] = page;
1184                 i_done++;
1185         }
1186         if (!i_done || ret)
1187                 goto out;
1188 
1189         if (!(inode->i_sb->s_flags & MS_ACTIVE))
1190                 goto out;
1191 
1192         /*
1193          * so now we have a nice long stream of locked
1194          * and up to date pages, lets wait on them
1195          */
1196         for (i = 0; i < i_done; i++)
1197                 wait_on_page_writeback(pages[i]);
1198 
1199         page_start = page_offset(pages[0]);
1200         page_end = page_offset(pages[i_done - 1]) + PAGE_CACHE_SIZE;
1201 
1202         lock_extent_bits(&BTRFS_I(inode)->io_tree,
1203                          page_start, page_end - 1, 0, &cached_state);
1204         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1205                           page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1206                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1207                           &cached_state, GFP_NOFS);
1208 
1209         if (i_done != page_cnt) {
1210                 spin_lock(&BTRFS_I(inode)->lock);
1211                 BTRFS_I(inode)->outstanding_extents++;
1212                 spin_unlock(&BTRFS_I(inode)->lock);
1213                 btrfs_delalloc_release_space(inode,
1214                                      (page_cnt - i_done) << PAGE_CACHE_SHIFT);
1215         }
1216 
1217 
1218         set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1219                           &cached_state, GFP_NOFS);
1220 
1221         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1222                              page_start, page_end - 1, &cached_state,
1223                              GFP_NOFS);
1224 
1225         for (i = 0; i < i_done; i++) {
1226                 clear_page_dirty_for_io(pages[i]);
1227                 ClearPageChecked(pages[i]);
1228                 set_page_extent_mapped(pages[i]);
1229                 set_page_dirty(pages[i]);
1230                 unlock_page(pages[i]);
1231                 page_cache_release(pages[i]);
1232         }
1233         return i_done;
1234 out:
1235         for (i = 0; i < i_done; i++) {
1236                 unlock_page(pages[i]);
1237                 page_cache_release(pages[i]);
1238         }
1239         btrfs_delalloc_release_space(inode, page_cnt << PAGE_CACHE_SHIFT);
1240         return ret;
1241 
1242 }
1243 
1244 int btrfs_defrag_file(struct inode *inode, struct file *file,
1245                       struct btrfs_ioctl_defrag_range_args *range,
1246                       u64 newer_than, unsigned long max_to_defrag)
1247 {
1248         struct btrfs_root *root = BTRFS_I(inode)->root;
1249         struct file_ra_state *ra = NULL;
1250         unsigned long last_index;
1251         u64 isize = i_size_read(inode);
1252         u64 last_len = 0;
1253         u64 skip = 0;
1254         u64 defrag_end = 0;
1255         u64 newer_off = range->start;
1256         unsigned long i;
1257         unsigned long ra_index = 0;
1258         int ret;
1259         int defrag_count = 0;
1260         int compress_type = BTRFS_COMPRESS_ZLIB;
1261         int extent_thresh = range->extent_thresh;
1262         unsigned long max_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
1263         unsigned long cluster = max_cluster;
1264         u64 new_align = ~((u64)128 * 1024 - 1);
1265         struct page **pages = NULL;
1266 
1267         if (isize == 0)
1268                 return 0;
1269 
1270         if (range->start >= isize)
1271                 return -EINVAL;
1272 
1273         if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1274                 if (range->compress_type > BTRFS_COMPRESS_TYPES)
1275                         return -EINVAL;
1276                 if (range->compress_type)
1277                         compress_type = range->compress_type;
1278         }
1279 
1280         if (extent_thresh == 0)
1281                 extent_thresh = 256 * 1024;
1282 
1283         /*
1284          * if we were not given a file, allocate a readahead
1285          * context
1286          */
1287         if (!file) {
1288                 ra = kzalloc(sizeof(*ra), GFP_NOFS);
1289                 if (!ra)
1290                         return -ENOMEM;
1291                 file_ra_state_init(ra, inode->i_mapping);
1292         } else {
1293                 ra = &file->f_ra;
1294         }
1295 
1296         pages = kmalloc_array(max_cluster, sizeof(struct page *),
1297                         GFP_NOFS);
1298         if (!pages) {
1299                 ret = -ENOMEM;
1300                 goto out_ra;
1301         }
1302 
1303         /* find the last page to defrag */
1304         if (range->start + range->len > range->start) {
1305                 last_index = min_t(u64, isize - 1,
1306                          range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
1307         } else {
1308                 last_index = (isize - 1) >> PAGE_CACHE_SHIFT;
1309         }
1310 
1311         if (newer_than) {
1312                 ret = find_new_extents(root, inode, newer_than,
1313                                        &newer_off, 64 * 1024);
1314                 if (!ret) {
1315                         range->start = newer_off;
1316                         /*
1317                          * we always align our defrag to help keep
1318                          * the extents in the file evenly spaced
1319                          */
1320                         i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1321                 } else
1322                         goto out_ra;
1323         } else {
1324                 i = range->start >> PAGE_CACHE_SHIFT;
1325         }
1326         if (!max_to_defrag)
1327                 max_to_defrag = last_index + 1;
1328 
1329         /*
1330          * make writeback starts from i, so the defrag range can be
1331          * written sequentially.
1332          */
1333         if (i < inode->i_mapping->writeback_index)
1334                 inode->i_mapping->writeback_index = i;
1335 
1336         while (i <= last_index && defrag_count < max_to_defrag &&
1337                (i < (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
1338                 PAGE_CACHE_SHIFT)) {
1339                 /*
1340                  * make sure we stop running if someone unmounts
1341                  * the FS
1342                  */
1343                 if (!(inode->i_sb->s_flags & MS_ACTIVE))
1344                         break;
1345 
1346                 if (btrfs_defrag_cancelled(root->fs_info)) {
1347                         printk(KERN_DEBUG "BTRFS: defrag_file cancelled\n");
1348                         ret = -EAGAIN;
1349                         break;
1350                 }
1351 
1352                 if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
1353                                          extent_thresh, &last_len, &skip,
1354                                          &defrag_end, range->flags &
1355                                          BTRFS_DEFRAG_RANGE_COMPRESS)) {
1356                         unsigned long next;
1357                         /*
1358                          * the should_defrag function tells us how much to skip
1359                          * bump our counter by the suggested amount
1360                          */
1361                         next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1362                         i = max(i + 1, next);
1363                         continue;
1364                 }
1365 
1366                 if (!newer_than) {
1367                         cluster = (PAGE_CACHE_ALIGN(defrag_end) >>
1368                                    PAGE_CACHE_SHIFT) - i;
1369                         cluster = min(cluster, max_cluster);
1370                 } else {
1371                         cluster = max_cluster;
1372                 }
1373 
1374                 if (i + cluster > ra_index) {
1375                         ra_index = max(i, ra_index);
1376                         btrfs_force_ra(inode->i_mapping, ra, file, ra_index,
1377                                        cluster);
1378                         ra_index += max_cluster;
1379                 }
1380 
1381                 mutex_lock(&inode->i_mutex);
1382                 if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
1383                         BTRFS_I(inode)->force_compress = compress_type;
1384                 ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1385                 if (ret < 0) {
1386                         mutex_unlock(&inode->i_mutex);
1387                         goto out_ra;
1388                 }
1389 
1390                 defrag_count += ret;
1391                 balance_dirty_pages_ratelimited(inode->i_mapping);
1392                 mutex_unlock(&inode->i_mutex);
1393 
1394                 if (newer_than) {
1395                         if (newer_off == (u64)-1)
1396                                 break;
1397 
1398                         if (ret > 0)
1399                                 i += ret;
1400 
1401                         newer_off = max(newer_off + 1,
1402                                         (u64)i << PAGE_CACHE_SHIFT);
1403 
1404                         ret = find_new_extents(root, inode,
1405                                                newer_than, &newer_off,
1406                                                64 * 1024);
1407                         if (!ret) {
1408                                 range->start = newer_off;
1409                                 i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1410                         } else {
1411                                 break;
1412                         }
1413                 } else {
1414                         if (ret > 0) {
1415                                 i += ret;
1416                                 last_len += ret << PAGE_CACHE_SHIFT;
1417                         } else {
1418                                 i++;
1419                                 last_len = 0;
1420                         }
1421                 }
1422         }
1423 
1424         if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1425                 filemap_flush(inode->i_mapping);
1426                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1427                              &BTRFS_I(inode)->runtime_flags))
1428                         filemap_flush(inode->i_mapping);
1429         }
1430 
1431         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1432                 /* the filemap_flush will queue IO into the worker threads, but
1433                  * we have to make sure the IO is actually started and that
1434                  * ordered extents get created before we return
1435                  */
1436                 atomic_inc(&root->fs_info->async_submit_draining);
1437                 while (atomic_read(&root->fs_info->nr_async_submits) ||
1438                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1439                         wait_event(root->fs_info->async_submit_wait,
1440                            (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
1441                             atomic_read(&root->fs_info->async_delalloc_pages) == 0));
1442                 }
1443                 atomic_dec(&root->fs_info->async_submit_draining);
1444         }
1445 
1446         if (range->compress_type == BTRFS_COMPRESS_LZO) {
1447                 btrfs_set_fs_incompat(root->fs_info, COMPRESS_LZO);
1448         }
1449 
1450         ret = defrag_count;
1451 
1452 out_ra:
1453         if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1454                 mutex_lock(&inode->i_mutex);
1455                 BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
1456                 mutex_unlock(&inode->i_mutex);
1457         }
1458         if (!file)
1459                 kfree(ra);
1460         kfree(pages);
1461         return ret;
1462 }
1463 
1464 static noinline int btrfs_ioctl_resize(struct file *file,
1465                                         void __user *arg)
1466 {
1467         u64 new_size;
1468         u64 old_size;
1469         u64 devid = 1;
1470         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
1471         struct btrfs_ioctl_vol_args *vol_args;
1472         struct btrfs_trans_handle *trans;
1473         struct btrfs_device *device = NULL;
1474         char *sizestr;
1475         char *retptr;
1476         char *devstr = NULL;
1477         int ret = 0;
1478         int mod = 0;
1479 
1480         if (!capable(CAP_SYS_ADMIN))
1481                 return -EPERM;
1482 
1483         ret = mnt_want_write_file(file);
1484         if (ret)
1485                 return ret;
1486 
1487         if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1488                         1)) {
1489                 mnt_drop_write_file(file);
1490                 return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1491         }
1492 
1493         mutex_lock(&root->fs_info->volume_mutex);
1494         vol_args = memdup_user(arg, sizeof(*vol_args));
1495         if (IS_ERR(vol_args)) {
1496                 ret = PTR_ERR(vol_args);
1497                 goto out;
1498         }
1499 
1500         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1501 
1502         sizestr = vol_args->name;
1503         devstr = strchr(sizestr, ':');
1504         if (devstr) {
1505                 char *end;
1506                 sizestr = devstr + 1;
1507                 *devstr = '\0';
1508                 devstr = vol_args->name;
1509                 devid = simple_strtoull(devstr, &end, 10);
1510                 if (!devid) {
1511                         ret = -EINVAL;
1512                         goto out_free;
1513                 }
1514                 btrfs_info(root->fs_info, "resizing devid %llu", devid);
1515         }
1516 
1517         device = btrfs_find_device(root->fs_info, devid, NULL, NULL);
1518         if (!device) {
1519                 btrfs_info(root->fs_info, "resizer unable to find device %llu",
1520                        devid);
1521                 ret = -ENODEV;
1522                 goto out_free;
1523         }
1524 
1525         if (!device->writeable) {
1526                 btrfs_info(root->fs_info,
1527                            "resizer unable to apply on readonly device %llu",
1528                        devid);
1529                 ret = -EPERM;
1530                 goto out_free;
1531         }
1532 
1533         if (!strcmp(sizestr, "max"))
1534                 new_size = device->bdev->bd_inode->i_size;
1535         else {
1536                 if (sizestr[0] == '-') {
1537                         mod = -1;
1538                         sizestr++;
1539                 } else if (sizestr[0] == '+') {
1540                         mod = 1;
1541                         sizestr++;
1542                 }
1543                 new_size = memparse(sizestr, &retptr);
1544                 if (*retptr != '\0' || new_size == 0) {
1545                         ret = -EINVAL;
1546                         goto out_free;
1547                 }
1548         }
1549 
1550         if (device->is_tgtdev_for_dev_replace) {
1551                 ret = -EPERM;
1552                 goto out_free;
1553         }
1554 
1555         old_size = device->total_bytes;
1556 
1557         if (mod < 0) {
1558                 if (new_size > old_size) {
1559                         ret = -EINVAL;
1560                         goto out_free;
1561                 }
1562                 new_size = old_size - new_size;
1563         } else if (mod > 0) {
1564                 if (new_size > ULLONG_MAX - old_size) {
1565                         ret = -EINVAL;
1566                         goto out_free;
1567                 }
1568                 new_size = old_size + new_size;
1569         }
1570 
1571         if (new_size < 256 * 1024 * 1024) {
1572                 ret = -EINVAL;
1573                 goto out_free;
1574         }
1575         if (new_size > device->bdev->bd_inode->i_size) {
1576                 ret = -EFBIG;
1577                 goto out_free;
1578         }
1579 
1580         do_div(new_size, root->sectorsize);
1581         new_size *= root->sectorsize;
1582 
1583         printk_in_rcu(KERN_INFO "BTRFS: new size for %s is %llu\n",
1584                       rcu_str_deref(device->name), new_size);
1585 
1586         if (new_size > old_size) {
1587                 trans = btrfs_start_transaction(root, 0);
1588                 if (IS_ERR(trans)) {
1589                         ret = PTR_ERR(trans);
1590                         goto out_free;
1591                 }
1592                 ret = btrfs_grow_device(trans, device, new_size);
1593                 btrfs_commit_transaction(trans, root);
1594         } else if (new_size < old_size) {
1595                 ret = btrfs_shrink_device(device, new_size);
1596         } /* equal, nothing need to do */
1597 
1598 out_free:
1599         kfree(vol_args);
1600 out:
1601         mutex_unlock(&root->fs_info->volume_mutex);
1602         atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
1603         mnt_drop_write_file(file);
1604         return ret;
1605 }
1606 
1607 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1608                                 char *name, unsigned long fd, int subvol,
1609                                 u64 *transid, bool readonly,
1610                                 struct btrfs_qgroup_inherit *inherit)
1611 {
1612         int namelen;
1613         int ret = 0;
1614 
1615         ret = mnt_want_write_file(file);
1616         if (ret)
1617                 goto out;
1618 
1619         namelen = strlen(name);
1620         if (strchr(name, '/')) {
1621                 ret = -EINVAL;
1622                 goto out_drop_write;
1623         }
1624 
1625         if (name[0] == '.' &&
1626            (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1627                 ret = -EEXIST;
1628                 goto out_drop_write;
1629         }
1630 
1631         if (subvol) {
1632                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
1633                                      NULL, transid, readonly, inherit);
1634         } else {
1635                 struct fd src = fdget(fd);
1636                 struct inode *src_inode;
1637                 if (!src.file) {
1638                         ret = -EINVAL;
1639                         goto out_drop_write;
1640                 }
1641 
1642                 src_inode = file_inode(src.file);
1643                 if (src_inode->i_sb != file_inode(file)->i_sb) {
1644                         btrfs_info(BTRFS_I(src_inode)->root->fs_info,
1645                                    "Snapshot src from another FS");
1646                         ret = -EXDEV;
1647                 } else if (!inode_owner_or_capable(src_inode)) {
1648                         /*
1649                          * Subvolume creation is not restricted, but snapshots
1650                          * are limited to own subvolumes only
1651                          */
1652                         ret = -EPERM;
1653                 } else {
1654                         ret = btrfs_mksubvol(&file->f_path, name, namelen,
1655                                              BTRFS_I(src_inode)->root,
1656                                              transid, readonly, inherit);
1657                 }
1658                 fdput(src);
1659         }
1660 out_drop_write:
1661         mnt_drop_write_file(file);
1662 out:
1663         return ret;
1664 }
1665 
1666 static noinline int btrfs_ioctl_snap_create(struct file *file,
1667                                             void __user *arg, int subvol)
1668 {
1669         struct btrfs_ioctl_vol_args *vol_args;
1670         int ret;
1671 
1672         vol_args = memdup_user(arg, sizeof(*vol_args));
1673         if (IS_ERR(vol_args))
1674                 return PTR_ERR(vol_args);
1675         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1676 
1677         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1678                                               vol_args->fd, subvol,
1679                                               NULL, false, NULL);
1680 
1681         kfree(vol_args);
1682         return ret;
1683 }
1684 
1685 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1686                                                void __user *arg, int subvol)
1687 {
1688         struct btrfs_ioctl_vol_args_v2 *vol_args;
1689         int ret;
1690         u64 transid = 0;
1691         u64 *ptr = NULL;
1692         bool readonly = false;
1693         struct btrfs_qgroup_inherit *inherit = NULL;
1694 
1695         vol_args = memdup_user(arg, sizeof(*vol_args));
1696         if (IS_ERR(vol_args))
1697                 return PTR_ERR(vol_args);
1698         vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1699 
1700         if (vol_args->flags &
1701             ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
1702               BTRFS_SUBVOL_QGROUP_INHERIT)) {
1703                 ret = -EOPNOTSUPP;
1704                 goto out;
1705         }
1706 
1707         if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
1708                 ptr = &transid;
1709         if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1710                 readonly = true;
1711         if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1712                 if (vol_args->size > PAGE_CACHE_SIZE) {
1713                         ret = -EINVAL;
1714                         goto out;
1715                 }
1716                 inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1717                 if (IS_ERR(inherit)) {
1718                         ret = PTR_ERR(inherit);
1719                         goto out;
1720                 }
1721         }
1722 
1723         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1724                                               vol_args->fd, subvol, ptr,
1725                                               readonly, inherit);
1726 
1727         if (ret == 0 && ptr &&
1728             copy_to_user(arg +
1729                          offsetof(struct btrfs_ioctl_vol_args_v2,
1730                                   transid), ptr, sizeof(*ptr)))
1731                 ret = -EFAULT;
1732 out:
1733         kfree(vol_args);
1734         kfree(inherit);
1735         return ret;
1736 }
1737 
1738 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1739                                                 void __user *arg)
1740 {
1741         struct inode *inode = file_inode(file);
1742         struct btrfs_root *root = BTRFS_I(inode)->root;
1743         int ret = 0;
1744         u64 flags = 0;
1745 
1746         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID)
1747                 return -EINVAL;
1748 
1749         down_read(&root->fs_info->subvol_sem);
1750         if (btrfs_root_readonly(root))
1751                 flags |= BTRFS_SUBVOL_RDONLY;
1752         up_read(&root->fs_info->subvol_sem);
1753 
1754         if (copy_to_user(arg, &flags, sizeof(flags)))
1755                 ret = -EFAULT;
1756 
1757         return ret;
1758 }
1759 
1760 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1761                                               void __user *arg)
1762 {
1763         struct inode *inode = file_inode(file);
1764         struct btrfs_root *root = BTRFS_I(inode)->root;
1765         struct btrfs_trans_handle *trans;
1766         u64 root_flags;
1767         u64 flags;
1768         int ret = 0;
1769 
1770         if (!inode_owner_or_capable(inode))
1771                 return -EPERM;
1772 
1773         ret = mnt_want_write_file(file);
1774         if (ret)
1775                 goto out;
1776 
1777         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
1778                 ret = -EINVAL;
1779                 goto out_drop_write;
1780         }
1781 
1782         if (copy_from_user(&flags, arg, sizeof(flags))) {
1783                 ret = -EFAULT;
1784                 goto out_drop_write;
1785         }
1786 
1787         if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1788                 ret = -EINVAL;
1789                 goto out_drop_write;
1790         }
1791 
1792         if (flags & ~BTRFS_SUBVOL_RDONLY) {
1793                 ret = -EOPNOTSUPP;
1794                 goto out_drop_write;
1795         }
1796 
1797         down_write(&root->fs_info->subvol_sem);
1798 
1799         /* nothing to do */
1800         if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1801                 goto out_drop_sem;
1802 
1803         root_flags = btrfs_root_flags(&root->root_item);
1804         if (flags & BTRFS_SUBVOL_RDONLY) {
1805                 btrfs_set_root_flags(&root->root_item,
1806                                      root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1807         } else {
1808                 /*
1809                  * Block RO -> RW transition if this subvolume is involved in
1810                  * send
1811                  */
1812                 spin_lock(&root->root_item_lock);
1813                 if (root->send_in_progress == 0) {
1814                         btrfs_set_root_flags(&root->root_item,
1815                                      root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1816                         spin_unlock(&root->root_item_lock);
1817                 } else {
1818                         spin_unlock(&root->root_item_lock);
1819                         btrfs_warn(root->fs_info,
1820                         "Attempt to set subvolume %llu read-write during send",
1821                                         root->root_key.objectid);
1822                         ret = -EPERM;
1823                         goto out_drop_sem;
1824                 }
1825         }
1826 
1827         trans = btrfs_start_transaction(root, 1);
1828         if (IS_ERR(trans)) {
1829                 ret = PTR_ERR(trans);
1830                 goto out_reset;
1831         }
1832 
1833         ret = btrfs_update_root(trans, root->fs_info->tree_root,
1834                                 &root->root_key, &root->root_item);
1835 
1836         btrfs_commit_transaction(trans, root);
1837 out_reset:
1838         if (ret)
1839                 btrfs_set_root_flags(&root->root_item, root_flags);
1840 out_drop_sem:
1841         up_write(&root->fs_info->subvol_sem);
1842 out_drop_write:
1843         mnt_drop_write_file(file);
1844 out:
1845         return ret;
1846 }
1847 
1848 /*
1849  * helper to check if the subvolume references other subvolumes
1850  */
1851 static noinline int may_destroy_subvol(struct btrfs_root *root)
1852 {
1853         struct btrfs_path *path;
1854         struct btrfs_dir_item *di;
1855         struct btrfs_key key;
1856         u64 dir_id;
1857         int ret;
1858 
1859         path = btrfs_alloc_path();
1860         if (!path)
1861                 return -ENOMEM;
1862 
1863         /* Make sure this root isn't set as the default subvol */
1864         dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
1865         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root, path,
1866                                    dir_id, "default", 7, 0);
1867         if (di && !IS_ERR(di)) {
1868                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
1869                 if (key.objectid == root->root_key.objectid) {
1870                         ret = -EPERM;
1871                         btrfs_err(root->fs_info, "deleting default subvolume "
1872                                   "%llu is not allowed", key.objectid);
1873                         goto out;
1874                 }
1875                 btrfs_release_path(path);
1876         }
1877 
1878         key.objectid = root->root_key.objectid;
1879         key.type = BTRFS_ROOT_REF_KEY;
1880         key.offset = (u64)-1;
1881 
1882         ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
1883                                 &key, path, 0, 0);
1884         if (ret < 0)
1885                 goto out;
1886         BUG_ON(ret == 0);
1887 
1888         ret = 0;
1889         if (path->slots[0] > 0) {
1890                 path->slots[0]--;
1891                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1892                 if (key.objectid == root->root_key.objectid &&
1893                     key.type == BTRFS_ROOT_REF_KEY)
1894                         ret = -ENOTEMPTY;
1895         }
1896 out:
1897         btrfs_free_path(path);
1898         return ret;
1899 }
1900 
1901 static noinline int key_in_sk(struct btrfs_key *key,
1902                               struct btrfs_ioctl_search_key *sk)
1903 {
1904         struct btrfs_key test;
1905         int ret;
1906 
1907         test.objectid = sk->min_objectid;
1908         test.type = sk->min_type;
1909         test.offset = sk->min_offset;
1910 
1911         ret = btrfs_comp_cpu_keys(key, &test);
1912         if (ret < 0)
1913                 return 0;
1914 
1915         test.objectid = sk->max_objectid;
1916         test.type = sk->max_type;
1917         test.offset = sk->max_offset;
1918 
1919         ret = btrfs_comp_cpu_keys(key, &test);
1920         if (ret > 0)
1921                 return 0;
1922         return 1;
1923 }
1924 
1925 static noinline int copy_to_sk(struct btrfs_root *root,
1926                                struct btrfs_path *path,
1927                                struct btrfs_key *key,
1928                                struct btrfs_ioctl_search_key *sk,
1929                                char *buf,
1930                                unsigned long *sk_offset,
1931                                int *num_found)
1932 {
1933         u64 found_transid;
1934         struct extent_buffer *leaf;
1935         struct btrfs_ioctl_search_header sh;
1936         unsigned long item_off;
1937         unsigned long item_len;
1938         int nritems;
1939         int i;
1940         int slot;
1941         int ret = 0;
1942 
1943         leaf = path->nodes[0];
1944         slot = path->slots[0];
1945         nritems = btrfs_header_nritems(leaf);
1946 
1947         if (btrfs_header_generation(leaf) > sk->max_transid) {
1948                 i = nritems;
1949                 goto advance_key;
1950         }
1951         found_transid = btrfs_header_generation(leaf);
1952 
1953         for (i = slot; i < nritems; i++) {
1954                 item_off = btrfs_item_ptr_offset(leaf, i);
1955                 item_len = btrfs_item_size_nr(leaf, i);
1956 
1957                 btrfs_item_key_to_cpu(leaf, key, i);
1958                 if (!key_in_sk(key, sk))
1959                         continue;
1960 
1961                 if (sizeof(sh) + item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
1962                         item_len = 0;
1963 
1964                 if (sizeof(sh) + item_len + *sk_offset >
1965                     BTRFS_SEARCH_ARGS_BUFSIZE) {
1966                         ret = 1;
1967                         goto overflow;
1968                 }
1969 
1970                 sh.objectid = key->objectid;
1971                 sh.offset = key->offset;
1972                 sh.type = key->type;
1973                 sh.len = item_len;
1974                 sh.transid = found_transid;
1975 
1976                 /* copy search result header */
1977                 memcpy(buf + *sk_offset, &sh, sizeof(sh));
1978                 *sk_offset += sizeof(sh);
1979 
1980                 if (item_len) {
1981                         char *p = buf + *sk_offset;
1982                         /* copy the item */
1983                         read_extent_buffer(leaf, p,
1984                                            item_off, item_len);
1985                         *sk_offset += item_len;
1986                 }
1987                 (*num_found)++;
1988 
1989                 if (*num_found >= sk->nr_items)
1990                         break;
1991         }
1992 advance_key:
1993         ret = 0;
1994         if (key->offset < (u64)-1 && key->offset < sk->max_offset)
1995                 key->offset++;
1996         else if (key->type < (u8)-1 && key->type < sk->max_type) {
1997                 key->offset = 0;
1998                 key->type++;
1999         } else if (key->objectid < (u64)-1 && key->objectid < sk->max_objectid) {
2000                 key->offset = 0;
2001                 key->type = 0;
2002                 key->objectid++;
2003         } else
2004                 ret = 1;
2005 overflow:
2006         return ret;
2007 }
2008 
2009 static noinline int search_ioctl(struct inode *inode,
2010                                  struct btrfs_ioctl_search_args *args)
2011 {
2012         struct btrfs_root *root;
2013         struct btrfs_key key;
2014         struct btrfs_path *path;
2015         struct btrfs_ioctl_search_key *sk = &args->key;
2016         struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
2017         int ret;
2018         int num_found = 0;
2019         unsigned long sk_offset = 0;
2020 
2021         path = btrfs_alloc_path();
2022         if (!path)
2023                 return -ENOMEM;
2024 
2025         if (sk->tree_id == 0) {
2026                 /* search the root of the inode that was passed */
2027                 root = BTRFS_I(inode)->root;
2028         } else {
2029                 key.objectid = sk->tree_id;
2030                 key.type = BTRFS_ROOT_ITEM_KEY;
2031                 key.offset = (u64)-1;
2032                 root = btrfs_read_fs_root_no_name(info, &key);
2033                 if (IS_ERR(root)) {
2034                         printk(KERN_ERR "BTRFS: could not find root %llu\n",
2035                                sk->tree_id);
2036                         btrfs_free_path(path);
2037                         return -ENOENT;
2038                 }
2039         }
2040 
2041         key.objectid = sk->min_objectid;
2042         key.type = sk->min_type;
2043         key.offset = sk->min_offset;
2044 
2045         path->keep_locks = 1;
2046 
2047         while (1) {
2048                 ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2049                 if (ret != 0) {
2050                         if (ret > 0)
2051                                 ret = 0;
2052                         goto err;
2053                 }
2054                 ret = copy_to_sk(root, path, &key, sk, args->buf,
2055                                  &sk_offset, &num_found);
2056                 btrfs_release_path(path);
2057                 if (ret || num_found >= sk->nr_items)
2058                         break;
2059 
2060         }
2061         ret = 0;
2062 err:
2063         sk->nr_items = num_found;
2064         btrfs_free_path(path);
2065         return ret;
2066 }
2067 
2068 static noinline int btrfs_ioctl_tree_search(struct file *file,
2069                                            void __user *argp)
2070 {
2071          struct btrfs_ioctl_search_args *args;
2072          struct inode *inode;
2073          int ret;
2074 
2075         if (!capable(CAP_SYS_ADMIN))
2076                 return -EPERM;
2077 
2078         args = memdup_user(argp, sizeof(*args));
2079         if (IS_ERR(args))
2080                 return PTR_ERR(args);
2081 
2082         inode = file_inode(file);
2083         ret = search_ioctl(inode, args);
2084         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2085                 ret = -EFAULT;
2086         kfree(args);
2087         return ret;
2088 }
2089 
2090 /*
2091  * Search INODE_REFs to identify path name of 'dirid' directory
2092  * in a 'tree_id' tree. and sets path name to 'name'.
2093  */
2094 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2095                                 u64 tree_id, u64 dirid, char *name)
2096 {
2097         struct btrfs_root *root;
2098         struct btrfs_key key;
2099         char *ptr;
2100         int ret = -1;
2101         int slot;
2102         int len;
2103         int total_len = 0;
2104         struct btrfs_inode_ref *iref;
2105         struct extent_buffer *l;
2106         struct btrfs_path *path;
2107 
2108         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2109                 name[0]='\0';
2110                 return 0;
2111         }
2112 
2113         path = btrfs_alloc_path();
2114         if (!path)
2115                 return -ENOMEM;
2116 
2117         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
2118 
2119         key.objectid = tree_id;
2120         key.type = BTRFS_ROOT_ITEM_KEY;
2121         key.offset = (u64)-1;
2122         root = btrfs_read_fs_root_no_name(info, &key);
2123         if (IS_ERR(root)) {
2124                 printk(KERN_ERR "BTRFS: could not find root %llu\n", tree_id);
2125                 ret = -ENOENT;
2126                 goto out;
2127         }
2128 
2129         key.objectid = dirid;
2130         key.type = BTRFS_INODE_REF_KEY;
2131         key.offset = (u64)-1;
2132 
2133         while (1) {
2134                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2135                 if (ret < 0)
2136                         goto out;
2137                 else if (ret > 0) {
2138                         ret = btrfs_previous_item(root, path, dirid,
2139                                                   BTRFS_INODE_REF_KEY);
2140                         if (ret < 0)
2141                                 goto out;
2142                         else if (ret > 0) {
2143                                 ret = -ENOENT;
2144                                 goto out;
2145                         }
2146                 }
2147 
2148                 l = path->nodes[0];
2149                 slot = path->slots[0];
2150                 btrfs_item_key_to_cpu(l, &key, slot);
2151 
2152                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2153                 len = btrfs_inode_ref_name_len(l, iref);
2154                 ptr -= len + 1;
2155                 total_len += len + 1;
2156                 if (ptr < name) {
2157                         ret = -ENAMETOOLONG;
2158                         goto out;
2159                 }
2160 
2161                 *(ptr + len) = '/';
2162                 read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2163 
2164                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2165                         break;
2166 
2167                 btrfs_release_path(path);
2168                 key.objectid = key.offset;
2169                 key.offset = (u64)-1;
2170                 dirid = key.objectid;
2171         }
2172         memmove(name, ptr, total_len);
2173         name[total_len] = '\0';
2174         ret = 0;
2175 out:
2176         btrfs_free_path(path);
2177         return ret;
2178 }
2179 
2180 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2181                                            void __user *argp)
2182 {
2183          struct btrfs_ioctl_ino_lookup_args *args;
2184          struct inode *inode;
2185          int ret;
2186 
2187         if (!capable(CAP_SYS_ADMIN))
2188                 return -EPERM;
2189 
2190         args = memdup_user(argp, sizeof(*args));
2191         if (IS_ERR(args))
2192                 return PTR_ERR(args);
2193 
2194         inode = file_inode(file);
2195 
2196         if (args->treeid == 0)
2197                 args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2198 
2199         ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2200                                         args->treeid, args->objectid,
2201                                         args->name);
2202 
2203         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2204                 ret = -EFAULT;
2205 
2206         kfree(args);
2207         return ret;
2208 }
2209 
2210 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2211                                              void __user *arg)
2212 {
2213         struct dentry *parent = file->f_path.dentry;
2214         struct dentry *dentry;
2215         struct inode *dir = parent->d_inode;
2216         struct inode *inode;
2217         struct btrfs_root *root = BTRFS_I(dir)->root;
2218         struct btrfs_root *dest = NULL;
2219         struct btrfs_ioctl_vol_args *vol_args;
2220         struct btrfs_trans_handle *trans;
2221         struct btrfs_block_rsv block_rsv;
2222         u64 qgroup_reserved;
2223         int namelen;
2224         int ret;
2225         int err = 0;
2226 
2227         vol_args = memdup_user(arg, sizeof(*vol_args));
2228         if (IS_ERR(vol_args))
2229                 return PTR_ERR(vol_args);
2230 
2231         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2232         namelen = strlen(vol_args->name);
2233         if (strchr(vol_args->name, '/') ||
2234             strncmp(vol_args->name, "..", namelen) == 0) {
2235                 err = -EINVAL;
2236                 goto out;
2237         }
2238 
2239         err = mnt_want_write_file(file);
2240         if (err)
2241                 goto out;
2242 
2243         err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT);
2244         if (err == -EINTR)
2245                 goto out_drop_write;
2246         dentry = lookup_one_len(vol_args->name, parent, namelen);
2247         if (IS_ERR(dentry)) {
2248                 err = PTR_ERR(dentry);
2249                 goto out_unlock_dir;
2250         }
2251 
2252         if (!dentry->d_inode) {
2253                 err = -ENOENT;
2254                 goto out_dput;
2255         }
2256 
2257         inode = dentry->d_inode;
2258         dest = BTRFS_I(inode)->root;
2259         if (!capable(CAP_SYS_ADMIN)) {
2260                 /*
2261                  * Regular user.  Only allow this with a special mount
2262                  * option, when the user has write+exec access to the
2263                  * subvol root, and when rmdir(2) would have been
2264                  * allowed.
2265                  *
2266                  * Note that this is _not_ check that the subvol is
2267                  * empty or doesn't contain data that we wouldn't
2268                  * otherwise be able to delete.
2269                  *
2270                  * Users who want to delete empty subvols should try
2271                  * rmdir(2).
2272                  */
2273                 err = -EPERM;
2274                 if (!btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
2275                         goto out_dput;
2276 
2277                 /*
2278                  * Do not allow deletion if the parent dir is the same
2279                  * as the dir to be deleted.  That means the ioctl
2280                  * must be called on the dentry referencing the root
2281                  * of the subvol, not a random directory contained
2282                  * within it.
2283                  */
2284                 err = -EINVAL;
2285                 if (root == dest)
2286                         goto out_dput;
2287 
2288                 err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2289                 if (err)
2290                         goto out_dput;
2291         }
2292 
2293         /* check if subvolume may be deleted by a user */
2294         err = btrfs_may_delete(dir, dentry, 1);
2295         if (err)
2296                 goto out_dput;
2297 
2298         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
2299                 err = -EINVAL;
2300                 goto out_dput;
2301         }
2302 
2303         mutex_lock(&inode->i_mutex);
2304         err = d_invalidate(dentry);
2305         if (err)
2306                 goto out_unlock;
2307 
2308         down_write(&root->fs_info->subvol_sem);
2309 
2310         err = may_destroy_subvol(dest);
2311         if (err)
2312                 goto out_up_write;
2313 
2314         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
2315         /*
2316          * One for dir inode, two for dir entries, two for root
2317          * ref/backref.
2318          */
2319         err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
2320                                                5, &qgroup_reserved, true);
2321         if (err)
2322                 goto out_up_write;
2323 
2324         trans = btrfs_start_transaction(root, 0);
2325         if (IS_ERR(trans)) {
2326                 err = PTR_ERR(trans);
2327                 goto out_release;
2328         }
2329         trans->block_rsv = &block_rsv;
2330         trans->bytes_reserved = block_rsv.size;
2331 
2332         ret = btrfs_unlink_subvol(trans, root, dir,
2333                                 dest->root_key.objectid,
2334                                 dentry->d_name.name,
2335                                 dentry->d_name.len);
2336         if (ret) {
2337                 err = ret;
2338                 btrfs_abort_transaction(trans, root, ret);
2339                 goto out_end_trans;
2340         }
2341 
2342         btrfs_record_root_in_trans(trans, dest);
2343 
2344         memset(&dest->root_item.drop_progress, 0,
2345                 sizeof(dest->root_item.drop_progress));
2346         dest->root_item.drop_level = 0;
2347         btrfs_set_root_refs(&dest->root_item, 0);
2348 
2349         if (!xchg(&dest->orphan_item_inserted, 1)) {
2350                 ret = btrfs_insert_orphan_item(trans,
2351                                         root->fs_info->tree_root,
2352                                         dest->root_key.objectid);
2353                 if (ret) {
2354                         btrfs_abort_transaction(trans, root, ret);
2355                         err = ret;
2356                         goto out_end_trans;
2357                 }
2358         }
2359 
2360         ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
2361                                   dest->root_item.uuid, BTRFS_UUID_KEY_SUBVOL,
2362                                   dest->root_key.objectid);
2363         if (ret && ret != -ENOENT) {
2364                 btrfs_abort_transaction(trans, root, ret);
2365                 err = ret;
2366                 goto out_end_trans;
2367         }
2368         if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
2369                 ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
2370                                           dest->root_item.received_uuid,
2371                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
2372                                           dest->root_key.objectid);
2373                 if (ret && ret != -ENOENT) {
2374                         btrfs_abort_transaction(trans, root, ret);
2375                         err = ret;
2376                         goto out_end_trans;
2377                 }
2378         }
2379 
2380 out_end_trans:
2381         trans->block_rsv = NULL;
2382         trans->bytes_reserved = 0;
2383         ret = btrfs_end_transaction(trans, root);
2384         if (ret && !err)
2385                 err = ret;
2386         inode->i_flags |= S_DEAD;
2387 out_release:
2388         btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
2389 out_up_write:
2390         up_write(&root->fs_info->subvol_sem);
2391 out_unlock:
2392         mutex_unlock(&inode->i_mutex);
2393         if (!err) {
2394                 shrink_dcache_sb(root->fs_info->sb);
2395                 btrfs_invalidate_inodes(dest);
2396                 d_delete(dentry);
2397 
2398                 /* the last ref */
2399                 if (dest->cache_inode) {
2400                         iput(dest->cache_inode);
2401                         dest->cache_inode = NULL;
2402                 }
2403         }
2404 out_dput:
2405         dput(dentry);
2406 out_unlock_dir:
2407         mutex_unlock(&dir->i_mutex);
2408 out_drop_write:
2409         mnt_drop_write_file(file);
2410 out:
2411         kfree(vol_args);
2412         return err;
2413 }
2414 
2415 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2416 {
2417         struct inode *inode = file_inode(file);
2418         struct btrfs_root *root = BTRFS_I(inode)->root;
2419         struct btrfs_ioctl_defrag_range_args *range;
2420         int ret;
2421 
2422         ret = mnt_want_write_file(file);
2423         if (ret)
2424                 return ret;
2425 
2426         if (btrfs_root_readonly(root)) {
2427                 ret = -EROFS;
2428                 goto out;
2429         }
2430 
2431         switch (inode->i_mode & S_IFMT) {
2432         case S_IFDIR:
2433                 if (!capable(CAP_SYS_ADMIN)) {
2434                         ret = -EPERM;
2435                         goto out;
2436                 }
2437                 ret = btrfs_defrag_root(root);
2438                 if (ret)
2439                         goto out;
2440                 ret = btrfs_defrag_root(root->fs_info->extent_root);
2441                 break;
2442         case S_IFREG:
2443                 if (!(file->f_mode & FMODE_WRITE)) {
2444                         ret = -EINVAL;
2445                         goto out;
2446                 }
2447 
2448                 range = kzalloc(sizeof(*range), GFP_KERNEL);
2449                 if (!range) {
2450                         ret = -ENOMEM;
2451                         goto out;
2452                 }
2453 
2454                 if (argp) {
2455                         if (copy_from_user(range, argp,
2456                                            sizeof(*range))) {
2457                                 ret = -EFAULT;
2458                                 kfree(range);
2459                                 goto out;
2460                         }
2461                         /* compression requires us to start the IO */
2462                         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2463                                 range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
2464                                 range->extent_thresh = (u32)-1;
2465                         }
2466                 } else {
2467                         /* the rest are all set to zero by kzalloc */
2468                         range->len = (u64)-1;
2469                 }
2470                 ret = btrfs_defrag_file(file_inode(file), file,
2471                                         range, 0, 0);
2472                 if (ret > 0)
2473                         ret = 0;
2474                 kfree(range);
2475                 break;
2476         default:
2477                 ret = -EINVAL;
2478         }
2479 out:
2480         mnt_drop_write_file(file);
2481         return ret;
2482 }
2483 
2484 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
2485 {
2486         struct btrfs_ioctl_vol_args *vol_args;
2487         int ret;
2488 
2489         if (!capable(CAP_SYS_ADMIN))
2490                 return -EPERM;
2491 
2492         if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
2493                         1)) {
2494                 return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2495         }
2496 
2497         mutex_lock(&root->fs_info->volume_mutex);
2498         vol_args = memdup_user(arg, sizeof(*vol_args));
2499         if (IS_ERR(vol_args)) {
2500                 ret = PTR_ERR(vol_args);
2501                 goto out;
2502         }
2503 
2504         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2505         ret = btrfs_init_new_device(root, vol_args->name);
2506 
2507         kfree(vol_args);
2508 out:
2509         mutex_unlock(&root->fs_info->volume_mutex);
2510         atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
2511         return ret;
2512 }
2513 
2514 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
2515 {
2516         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
2517         struct btrfs_ioctl_vol_args *vol_args;
2518         int ret;
2519 
2520         if (!capable(CAP_SYS_ADMIN))
2521                 return -EPERM;
2522 
2523         ret = mnt_want_write_file(file);
2524         if (ret)
2525                 return ret;
2526 
2527         vol_args = memdup_user(arg, sizeof(*vol_args));
2528         if (IS_ERR(vol_args)) {
2529                 ret = PTR_ERR(vol_args);
2530                 goto out;
2531         }
2532 
2533         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2534 
2535         if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
2536                         1)) {
2537                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2538                 goto out;
2539         }
2540 
2541         mutex_lock(&root->fs_info->volume_mutex);
2542         ret = btrfs_rm_device(root, vol_args->name);
2543         mutex_unlock(&root->fs_info->volume_mutex);
2544         atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
2545 
2546 out:
2547         kfree(vol_args);
2548         mnt_drop_write_file(file);
2549         return ret;
2550 }
2551 
2552 static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
2553 {
2554         struct btrfs_ioctl_fs_info_args *fi_args;
2555         struct btrfs_device *device;
2556         struct btrfs_device *next;
2557         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2558         int ret = 0;
2559 
2560         if (!capable(CAP_SYS_ADMIN))
2561                 return -EPERM;
2562 
2563         fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
2564         if (!fi_args)
2565                 return -ENOMEM;
2566 
2567         mutex_lock(&fs_devices->device_list_mutex);
2568         fi_args->num_devices = fs_devices->num_devices;
2569         memcpy(&fi_args->fsid, root->fs_info->fsid, sizeof(fi_args->fsid));
2570 
2571         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
2572                 if (device->devid > fi_args->max_id)
2573                         fi_args->max_id = device->devid;
2574         }
2575         mutex_unlock(&fs_devices->device_list_mutex);
2576 
2577         if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
2578                 ret = -EFAULT;
2579 
2580         kfree(fi_args);
2581         return ret;
2582 }
2583 
2584 static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg)
2585 {
2586         struct btrfs_ioctl_dev_info_args *di_args;
2587         struct btrfs_device *dev;
2588         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2589         int ret = 0;
2590         char *s_uuid = NULL;
2591 
2592         if (!capable(CAP_SYS_ADMIN))
2593                 return -EPERM;
2594 
2595         di_args = memdup_user(arg, sizeof(*di_args));
2596         if (IS_ERR(di_args))
2597                 return PTR_ERR(di_args);
2598 
2599         if (!btrfs_is_empty_uuid(di_args->uuid))
2600                 s_uuid = di_args->uuid;
2601 
2602         mutex_lock(&fs_devices->device_list_mutex);
2603         dev = btrfs_find_device(root->fs_info, di_args->devid, s_uuid, NULL);
2604 
2605         if (!dev) {
2606                 ret = -ENODEV;
2607                 goto out;
2608         }
2609 
2610         di_args->devid = dev->devid;
2611         di_args->bytes_used = dev->bytes_used;
2612         di_args->total_bytes = dev->total_bytes;
2613         memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2614         if (dev->name) {
2615                 struct rcu_string *name;
2616 
2617                 rcu_read_lock();
2618                 name = rcu_dereference(dev->name);
2619                 strncpy(di_args->path, name->str, sizeof(di_args->path));
2620                 rcu_read_unlock();
2621                 di_args->path[sizeof(di_args->path) - 1] = 0;
2622         } else {
2623                 di_args->path[0] = '\0';
2624         }
2625 
2626 out:
2627         mutex_unlock(&fs_devices->device_list_mutex);
2628         if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2629                 ret = -EFAULT;
2630 
2631         kfree(di_args);
2632         return ret;
2633 }
2634 
2635 static struct page *extent_same_get_page(struct inode *inode, u64 off)
2636 {
2637         struct page *page;
2638         pgoff_t index;
2639         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2640 
2641         index = off >> PAGE_CACHE_SHIFT;
2642 
2643         page = grab_cache_page(inode->i_mapping, index);
2644         if (!page)
2645                 return NULL;
2646 
2647         if (!PageUptodate(page)) {
2648                 if (extent_read_full_page_nolock(tree, page, btrfs_get_extent,
2649                                                  0))
2650                         return NULL;
2651                 lock_page(page);
2652                 if (!PageUptodate(page)) {
2653                         unlock_page(page);
2654                         page_cache_release(page);
2655                         return NULL;
2656                 }
2657         }
2658         unlock_page(page);
2659 
2660         return page;
2661 }
2662 
2663 static inline void lock_extent_range(struct inode *inode, u64 off, u64 len)
2664 {
2665         /* do any pending delalloc/csum calc on src, one way or
2666            another, and lock file content */
2667         while (1) {
2668                 struct btrfs_ordered_extent *ordered;
2669                 lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2670                 ordered = btrfs_lookup_first_ordered_extent(inode,
2671                                                             off + len - 1);
2672                 if (!ordered &&
2673                     !test_range_bit(&BTRFS_I(inode)->io_tree, off,
2674                                     off + len - 1, EXTENT_DELALLOC, 0, NULL))
2675                         break;
2676                 unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2677                 if (ordered)
2678                         btrfs_put_ordered_extent(ordered);
2679                 btrfs_wait_ordered_range(inode, off, len);
2680         }
2681 }
2682 
2683 static void btrfs_double_unlock(struct inode *inode1, u64 loff1,
2684                                 struct inode *inode2, u64 loff2, u64 len)
2685 {
2686         unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
2687         unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
2688 
2689         mutex_unlock(&inode1->i_mutex);
2690         mutex_unlock(&inode2->i_mutex);
2691 }
2692 
2693 static void btrfs_double_lock(struct inode *inode1, u64 loff1,
2694                               struct inode *inode2, u64 loff2, u64 len)
2695 {
2696         if (inode1 < inode2) {
2697                 swap(inode1, inode2);
2698                 swap(loff1, loff2);
2699         }
2700 
2701         mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
2702         lock_extent_range(inode1, loff1, len);
2703         if (inode1 != inode2) {
2704                 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
2705                 lock_extent_range(inode2, loff2, len);
2706         }
2707 }
2708 
2709 static int btrfs_cmp_data(struct inode *src, u64 loff, struct inode *dst,
2710                           u64 dst_loff, u64 len)
2711 {
2712         int ret = 0;
2713         struct page *src_page, *dst_page;
2714         unsigned int cmp_len = PAGE_CACHE_SIZE;
2715         void *addr, *dst_addr;
2716 
2717         while (len) {
2718                 if (len < PAGE_CACHE_SIZE)
2719                         cmp_len = len;
2720 
2721                 src_page = extent_same_get_page(src, loff);
2722                 if (!src_page)
2723                         return -EINVAL;
2724                 dst_page = extent_same_get_page(dst, dst_loff);
2725                 if (!dst_page) {
2726                         page_cache_release(src_page);
2727                         return -EINVAL;
2728                 }
2729                 addr = kmap_atomic(src_page);
2730                 dst_addr = kmap_atomic(dst_page);
2731 
2732                 flush_dcache_page(src_page);
2733                 flush_dcache_page(dst_page);
2734 
2735                 if (memcmp(addr, dst_addr, cmp_len))
2736                         ret = BTRFS_SAME_DATA_DIFFERS;
2737 
2738                 kunmap_atomic(addr);
2739                 kunmap_atomic(dst_addr);
2740                 page_cache_release(src_page);
2741                 page_cache_release(dst_page);
2742 
2743                 if (ret)
2744                         break;
2745 
2746                 loff += cmp_len;
2747                 dst_loff += cmp_len;
2748                 len -= cmp_len;
2749         }
2750 
2751         return ret;
2752 }
2753 
2754 static int extent_same_check_offsets(struct inode *inode, u64 off, u64 len)
2755 {
2756         u64 bs = BTRFS_I(inode)->root->fs_info->sb->s_blocksize;
2757 
2758         if (off + len > inode->i_size || off + len < off)
2759                 return -EINVAL;
2760         /* Check that we are block aligned - btrfs_clone() requires this */
2761         if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs))
2762                 return -EINVAL;
2763 
2764         return 0;
2765 }
2766 
2767 static int btrfs_extent_same(struct inode *src, u64 loff, u64 len,
2768                              struct inode *dst, u64 dst_loff)
2769 {
2770         int ret;
2771 
2772         /*
2773          * btrfs_clone() can't handle extents in the same file
2774          * yet. Once that works, we can drop this check and replace it
2775          * with a check for the same inode, but overlapping extents.
2776          */
2777         if (src == dst)
2778                 return -EINVAL;
2779 
2780         btrfs_double_lock(src, loff, dst, dst_loff, len);
2781 
2782         ret = extent_same_check_offsets(src, loff, len);
2783         if (ret)
2784                 goto out_unlock;
2785 
2786         ret = extent_same_check_offsets(dst, dst_loff, len);
2787         if (ret)
2788                 goto out_unlock;
2789 
2790         /* don't make the dst file partly checksummed */
2791         if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
2792             (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
2793                 ret = -EINVAL;
2794                 goto out_unlock;
2795         }
2796 
2797         ret = btrfs_cmp_data(src, loff, dst, dst_loff, len);
2798         if (ret == 0)
2799                 ret = btrfs_clone(src, dst, loff, len, len, dst_loff);
2800 
2801 out_unlock:
2802         btrfs_double_unlock(src, loff, dst, dst_loff, len);
2803 
2804         return ret;
2805 }
2806 
2807 #define BTRFS_MAX_DEDUPE_LEN    (16 * 1024 * 1024)
2808 
2809 static long btrfs_ioctl_file_extent_same(struct file *file,
2810                         struct btrfs_ioctl_same_args __user *argp)
2811 {
2812         struct btrfs_ioctl_same_args *same;
2813         struct btrfs_ioctl_same_extent_info *info;
2814         struct inode *src = file_inode(file);
2815         u64 off;
2816         u64 len;
2817         int i;
2818         int ret;
2819         unsigned long size;
2820         u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
2821         bool is_admin = capable(CAP_SYS_ADMIN);
2822         u16 count;
2823 
2824         if (!(file->f_mode & FMODE_READ))
2825                 return -EINVAL;
2826 
2827         ret = mnt_want_write_file(file);
2828         if (ret)
2829                 return ret;
2830 
2831         if (get_user(count, &argp->dest_count)) {
2832                 ret = -EFAULT;
2833                 goto out;
2834         }
2835 
2836         size = offsetof(struct btrfs_ioctl_same_args __user, info[count]);
2837 
2838         same = memdup_user(argp, size);
2839 
2840         if (IS_ERR(same)) {
2841                 ret = PTR_ERR(same);
2842                 goto out;
2843         }
2844 
2845         off = same->logical_offset;
2846         len = same->length;
2847 
2848         /*
2849          * Limit the total length we will dedupe for each operation.
2850          * This is intended to bound the total time spent in this
2851          * ioctl to something sane.
2852          */
2853         if (len > BTRFS_MAX_DEDUPE_LEN)
2854                 len = BTRFS_MAX_DEDUPE_LEN;
2855 
2856         if (WARN_ON_ONCE(bs < PAGE_CACHE_SIZE)) {
2857                 /*
2858                  * Btrfs does not support blocksize < page_size. As a
2859                  * result, btrfs_cmp_data() won't correctly handle
2860                  * this situation without an update.
2861                  */
2862                 ret = -EINVAL;
2863                 goto out;
2864         }
2865 
2866         ret = -EISDIR;
2867         if (S_ISDIR(src->i_mode))
2868                 goto out;
2869 
2870         ret = -EACCES;
2871         if (!S_ISREG(src->i_mode))
2872                 goto out;
2873 
2874         /* pre-format output fields to sane values */
2875         for (i = 0; i < count; i++) {
2876                 same->info[i].bytes_deduped = 0ULL;
2877                 same->info[i].status = 0;
2878         }
2879 
2880         for (i = 0, info = same->info; i < count; i++, info++) {
2881                 struct inode *dst;
2882                 struct fd dst_file = fdget(info->fd);
2883                 if (!dst_file.file) {
2884                         info->status = -EBADF;
2885                         continue;
2886                 }
2887                 dst = file_inode(dst_file.file);
2888 
2889                 if (!(is_admin || (dst_file.file->f_mode & FMODE_WRITE))) {
2890                         info->status = -EINVAL;
2891                 } else if (file->f_path.mnt != dst_file.file->f_path.mnt) {
2892                         info->status = -EXDEV;
2893                 } else if (S_ISDIR(dst->i_mode)) {
2894                         info->status = -EISDIR;
2895                 } else if (!S_ISREG(dst->i_mode)) {
2896                         info->status = -EACCES;
2897                 } else {
2898                         info->status = btrfs_extent_same(src, off, len, dst,
2899                                                         info->logical_offset);
2900                         if (info->status == 0)
2901                                 info->bytes_deduped += len;
2902                 }
2903                 fdput(dst_file);
2904         }
2905 
2906         ret = copy_to_user(argp, same, size);
2907         if (ret)
2908                 ret = -EFAULT;
2909 
2910 out:
2911         mnt_drop_write_file(file);
2912         return ret;
2913 }
2914 
2915 /**
2916  * btrfs_clone() - clone a range from inode file to another
2917  *
2918  * @src: Inode to clone from
2919  * @inode: Inode to clone to
2920  * @off: Offset within source to start clone from
2921  * @olen: Original length, passed by user, of range to clone
2922  * @olen_aligned: Block-aligned value of olen, extent_same uses
2923  *               identical values here
2924  * @destoff: Offset within @inode to start clone
2925  */
2926 static int btrfs_clone(struct inode *src, struct inode *inode,
2927                        u64 off, u64 olen, u64 olen_aligned, u64 destoff)
2928 {
2929         struct btrfs_root *root = BTRFS_I(inode)->root;
2930         struct btrfs_path *path = NULL;
2931         struct extent_buffer *leaf;
2932         struct btrfs_trans_handle *trans;
2933         char *buf = NULL;
2934         struct btrfs_key key;
2935         u32 nritems;
2936         int slot;
2937         int ret;
2938         u64 len = olen_aligned;
2939 
2940         ret = -ENOMEM;
2941         buf = vmalloc(btrfs_level_size(root, 0));
2942         if (!buf)
2943                 return ret;
2944 
2945         path = btrfs_alloc_path();
2946         if (!path) {
2947                 vfree(buf);
2948                 return ret;
2949         }
2950 
2951         path->reada = 2;
2952         /* clone data */
2953         key.objectid = btrfs_ino(src);
2954         key.type = BTRFS_EXTENT_DATA_KEY;
2955         key.offset = 0;
2956 
2957         while (1) {
2958                 /*
2959                  * note the key will change type as we walk through the
2960                  * tree.
2961                  */
2962                 path->leave_spinning = 1;
2963                 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
2964                                 0, 0);
2965                 if (ret < 0)
2966                         goto out;
2967 
2968                 nritems = btrfs_header_nritems(path->nodes[0]);
2969 process_slot:
2970                 if (path->slots[0] >= nritems) {
2971                         ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
2972                         if (ret < 0)
2973                                 goto out;
2974                         if (ret > 0)
2975                                 break;
2976                         nritems = btrfs_header_nritems(path->nodes[0]);
2977                 }
2978                 leaf = path->nodes[0];
2979                 slot = path->slots[0];
2980 
2981                 btrfs_item_key_to_cpu(leaf, &key, slot);
2982                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
2983                     key.objectid != btrfs_ino(src))
2984                         break;
2985 
2986                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
2987                         struct btrfs_file_extent_item *extent;
2988                         int type;
2989                         u32 size;
2990                         struct btrfs_key new_key;
2991                         u64 disko = 0, diskl = 0;
2992                         u64 datao = 0, datal = 0;
2993                         u8 comp;
2994                         u64 endoff;
2995 
2996                         extent = btrfs_item_ptr(leaf, slot,
2997                                                 struct btrfs_file_extent_item);
2998                         comp = btrfs_file_extent_compression(leaf, extent);
2999                         type = btrfs_file_extent_type(leaf, extent);
3000                         if (type == BTRFS_FILE_EXTENT_REG ||
3001                             type == BTRFS_FILE_EXTENT_PREALLOC) {
3002                                 disko = btrfs_file_extent_disk_bytenr(leaf,
3003                                                                       extent);
3004                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
3005                                                                  extent);
3006                                 datao = btrfs_file_extent_offset(leaf, extent);
3007                                 datal = btrfs_file_extent_num_bytes(leaf,
3008                                                                     extent);
3009                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
3010                                 /* take upper bound, may be compressed */
3011                                 datal = btrfs_file_extent_ram_bytes(leaf,
3012                                                                     extent);
3013                         }
3014 
3015                         if (key.offset + datal <= off ||
3016                             key.offset >= off + len - 1) {
3017                                 path->slots[0]++;
3018                                 goto process_slot;
3019                         }
3020 
3021                         size = btrfs_item_size_nr(leaf, slot);
3022                         read_extent_buffer(leaf, buf,
3023                                            btrfs_item_ptr_offset(leaf, slot),
3024                                            size);
3025 
3026                         btrfs_release_path(path);
3027                         path->leave_spinning = 0;
3028 
3029                         memcpy(&new_key, &key, sizeof(new_key));
3030                         new_key.objectid = btrfs_ino(inode);
3031                         if (off <= key.offset)
3032                                 new_key.offset = key.offset + destoff - off;
3033                         else
3034                                 new_key.offset = destoff;
3035 
3036                         /*
3037                          * 1 - adjusting old extent (we may have to split it)
3038                          * 1 - add new extent
3039                          * 1 - inode update
3040                          */
3041                         trans = btrfs_start_transaction(root, 3);
3042                         if (IS_ERR(trans)) {
3043                                 ret = PTR_ERR(trans);
3044                                 goto out;
3045                         }
3046 
3047                         if (type == BTRFS_FILE_EXTENT_REG ||
3048                             type == BTRFS_FILE_EXTENT_PREALLOC) {
3049                                 /*
3050                                  *    a  | --- range to clone ---|  b
3051                                  * | ------------- extent ------------- |
3052                                  */
3053 
3054                                 /* substract range b */
3055                                 if (key.offset + datal > off + len)
3056                                         datal = off + len - key.offset;
3057 
3058                                 /* substract range a */
3059                                 if (off > key.offset) {
3060                                         datao += off - key.offset;
3061                                         datal -= off - key.offset;
3062                                 }
3063 
3064                                 ret = btrfs_drop_extents(trans, root, inode,
3065                                                          new_key.offset,
3066                                                          new_key.offset + datal,
3067                                                          1);
3068                                 if (ret) {
3069                                         if (ret != -EOPNOTSUPP)
3070                                                 btrfs_abort_transaction(trans,
3071                                                                 root, ret);
3072                                         btrfs_end_transaction(trans, root);
3073                                         goto out;
3074                                 }
3075 
3076                                 ret = btrfs_insert_empty_item(trans, root, path,
3077                                                               &new_key, size);
3078                                 if (ret) {
3079                                         btrfs_abort_transaction(trans, root,
3080                                                                 ret);
3081                                         btrfs_end_transaction(trans, root);
3082                                         goto out;
3083                                 }
3084 
3085                                 leaf = path->nodes[0];
3086                                 slot = path->slots[0];
3087                                 write_extent_buffer(leaf, buf,
3088                                             btrfs_item_ptr_offset(leaf, slot),
3089                                             size);
3090 
3091                                 extent = btrfs_item_ptr(leaf, slot,
3092                                                 struct btrfs_file_extent_item);
3093 
3094                                 /* disko == 0 means it's a hole */
3095                                 if (!disko)
3096                                         datao = 0;
3097 
3098                                 btrfs_set_file_extent_offset(leaf, extent,
3099                                                              datao);
3100                                 btrfs_set_file_extent_num_bytes(leaf, extent,
3101                                                                 datal);
3102                                 if (disko) {
3103                                         inode_add_bytes(inode, datal);
3104                                         ret = btrfs_inc_extent_ref(trans, root,
3105                                                         disko, diskl, 0,
3106                                                         root->root_key.objectid,
3107                                                         btrfs_ino(inode),
3108                                                         new_key.offset - datao,
3109                                                         0);
3110                                         if (ret) {
3111                                                 btrfs_abort_transaction(trans,
3112                                                                         root,
3113                                                                         ret);
3114                                                 btrfs_end_transaction(trans,
3115                                                                       root);
3116                                                 goto out;
3117 
3118                                         }
3119                                 }
3120                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
3121                                 u64 skip = 0;
3122                                 u64 trim = 0;
3123                                 u64 aligned_end = 0;
3124 
3125                                 if (off > key.offset) {
3126                                         skip = off - key.offset;
3127                                         new_key.offset += skip;
3128                                 }
3129 
3130                                 if (key.offset + datal > off + len)
3131                                         trim = key.offset + datal - (off + len);
3132 
3133                                 if (comp && (skip || trim)) {
3134                                         ret = -EINVAL;
3135                                         btrfs_end_transaction(trans, root);
3136                                         goto out;
3137                                 }
3138                                 size -= skip + trim;
3139                                 datal -= skip + trim;
3140 
3141                                 aligned_end = ALIGN(new_key.offset + datal,
3142                                                     root->sectorsize);
3143                                 ret = btrfs_drop_extents(trans, root, inode,
3144                                                          new_key.offset,
3145                                                          aligned_end,
3146                                                          1);
3147                                 if (ret) {
3148                                         if (ret != -EOPNOTSUPP)
3149                                                 btrfs_abort_transaction(trans,
3150                                                         root, ret);
3151                                         btrfs_end_transaction(trans, root);
3152                                         goto out;
3153                                 }
3154 
3155                                 ret = btrfs_insert_empty_item(trans, root, path,
3156                                                               &new_key, size);
3157                                 if (ret) {
3158                                         btrfs_abort_transaction(trans, root,
3159                                                                 ret);
3160                                         btrfs_end_transaction(trans, root);
3161                                         goto out;
3162                                 }
3163 
3164                                 if (skip) {
3165                                         u32 start =
3166                                           btrfs_file_extent_calc_inline_size(0);
3167                                         memmove(buf+start, buf+start+skip,
3168                                                 datal);
3169                                 }
3170 
3171                                 leaf = path->nodes[0];
3172                                 slot = path->slots[0];
3173                                 write_extent_buffer(leaf, buf,
3174                                             btrfs_item_ptr_offset(leaf, slot),
3175                                             size);
3176                                 inode_add_bytes(inode, datal);
3177                         }
3178 
3179                         btrfs_mark_buffer_dirty(leaf);
3180                         btrfs_release_path(path);
3181 
3182                         inode_inc_iversion(inode);
3183                         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
3184 
3185                         /*
3186                          * we round up to the block size at eof when
3187                          * determining which extents to clone above,
3188                          * but shouldn't round up the file size
3189                          */
3190                         endoff = new_key.offset + datal;
3191                         if (endoff > destoff+olen)
3192                                 endoff = destoff+olen;
3193                         if (endoff > inode->i_size)
3194                                 btrfs_i_size_write(inode, endoff);
3195 
3196                         ret = btrfs_update_inode(trans, root, inode);
3197                         if (ret) {
3198                                 btrfs_abort_transaction(trans, root, ret);
3199                                 btrfs_end_transaction(trans, root);
3200                                 goto out;
3201                         }
3202                         ret = btrfs_end_transaction(trans, root);
3203                 }
3204                 btrfs_release_path(path);
3205                 key.offset++;
3206         }
3207         ret = 0;
3208 
3209 out:
3210         btrfs_release_path(path);
3211         btrfs_free_path(path);
3212         vfree(buf);
3213         return ret;
3214 }
3215 
3216 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
3217                                        u64 off, u64 olen, u64 destoff)
3218 {
3219         struct inode *inode = file_inode(file);
3220         struct btrfs_root *root = BTRFS_I(inode)->root;
3221         struct fd src_file;
3222         struct inode *src;
3223         int ret;
3224         u64 len = olen;
3225         u64 bs = root->fs_info->sb->s_blocksize;
3226         int same_inode = 0;
3227 
3228         /*
3229          * TODO:
3230          * - split compressed inline extents.  annoying: we need to
3231          *   decompress into destination's address_space (the file offset
3232          *   may change, so source mapping won't do), then recompress (or
3233          *   otherwise reinsert) a subrange.
3234          *
3235          * - split destination inode's inline extents.  The inline extents can
3236          *   be either compressed or non-compressed.
3237          */
3238 
3239         /* the destination must be opened for writing */
3240         if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
3241                 return -EINVAL;
3242 
3243         if (btrfs_root_readonly(root))
3244                 return -EROFS;
3245 
3246         ret = mnt_want_write_file(file);
3247         if (ret)
3248                 return ret;
3249 
3250         src_file = fdget(srcfd);
3251         if (!src_file.file) {
3252                 ret = -EBADF;
3253                 goto out_drop_write;
3254         }
3255 
3256         ret = -EXDEV;
3257         if (src_file.file->f_path.mnt != file->f_path.mnt)
3258                 goto out_fput;
3259 
3260         src = file_inode(src_file.file);
3261 
3262         ret = -EINVAL;
3263         if (src == inode)
3264                 same_inode = 1;
3265 
3266         /* the src must be open for reading */
3267         if (!(src_file.file->f_mode & FMODE_READ))
3268                 goto out_fput;
3269 
3270         /* don't make the dst file partly checksummed */
3271         if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3272             (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
3273                 goto out_fput;
3274 
3275         ret = -EISDIR;
3276         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
3277                 goto out_fput;
3278 
3279         ret = -EXDEV;
3280         if (src->i_sb != inode->i_sb)
3281                 goto out_fput;
3282 
3283         if (!same_inode) {
3284                 if (inode < src) {
3285                         mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
3286                         mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
3287                 } else {
3288                         mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
3289                         mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
3290                 }
3291         } else {
3292                 mutex_lock(&src->i_mutex);
3293         }
3294 
3295         /* determine range to clone */
3296         ret = -EINVAL;
3297         if (off + len > src->i_size || off + len < off)
3298                 goto out_unlock;
3299         if (len == 0)
3300                 olen = len = src->i_size - off;
3301         /* if we extend to eof, continue to block boundary */
3302         if (off + len == src->i_size)
3303                 len = ALIGN(src->i_size, bs) - off;
3304 
3305         /* verify the end result is block aligned */
3306         if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
3307             !IS_ALIGNED(destoff, bs))
3308                 goto out_unlock;
3309 
3310         /* verify if ranges are overlapped within the same file */
3311         if (same_inode) {
3312                 if (destoff + len > off && destoff < off + len)
3313                         goto out_unlock;
3314         }
3315 
3316         if (destoff > inode->i_size) {
3317                 ret = btrfs_cont_expand(inode, inode->i_size, destoff);
3318                 if (ret)
3319                         goto out_unlock;
3320         }
3321 
3322         /* truncate page cache pages from target inode range */
3323         truncate_inode_pages_range(&inode->i_data, destoff,
3324                                    PAGE_CACHE_ALIGN(destoff + len) - 1);
3325 
3326         lock_extent_range(src, off, len);
3327 
3328         ret = btrfs_clone(src, inode, off, olen, len, destoff);
3329 
3330         unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1);
3331 out_unlock:
3332         if (!same_inode) {
3333                 if (inode < src) {
3334                         mutex_unlock(&src->i_mutex);
3335                         mutex_unlock(&inode->i_mutex);
3336                 } else {
3337                         mutex_unlock(&inode->i_mutex);
3338                         mutex_unlock(&src->i_mutex);
3339                 }
3340         } else {
3341                 mutex_unlock(&src->i_mutex);
3342         }
3343 out_fput:
3344         fdput(src_file);
3345 out_drop_write:
3346         mnt_drop_write_file(file);
3347         return ret;
3348 }
3349 
3350 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
3351 {
3352         struct btrfs_ioctl_clone_range_args args;
3353 
3354         if (copy_from_user(&args, argp, sizeof(args)))
3355                 return -EFAULT;
3356         return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
3357                                  args.src_length, args.dest_offset);
3358 }
3359 
3360 /*
3361  * there are many ways the trans_start and trans_end ioctls can lead
3362  * to deadlocks.  They should only be used by applications that
3363  * basically own the machine, and have a very in depth understanding
3364  * of all the possible deadlocks and enospc problems.
3365  */
3366 static long btrfs_ioctl_trans_start(struct file *file)
3367 {
3368         struct inode *inode = file_inode(file);
3369         struct btrfs_root *root = BTRFS_I(inode)->root;
3370         struct btrfs_trans_handle *trans;
3371         int ret;
3372 
3373         ret = -EPERM;
3374         if (!capable(CAP_SYS_ADMIN))
3375                 goto out;
3376 
3377         ret = -EINPROGRESS;
3378         if (file->private_data)
3379                 goto out;
3380 
3381         ret = -EROFS;
3382         if (btrfs_root_readonly(root))
3383                 goto out;
3384 
3385         ret = mnt_want_write_file(file);
3386         if (ret)
3387                 goto out;
3388 
3389         atomic_inc(&root->fs_info->open_ioctl_trans);
3390 
3391         ret = -ENOMEM;
3392         trans = btrfs_start_ioctl_transaction(root);
3393         if (IS_ERR(trans))
3394                 goto out_drop;
3395 
3396         file->private_data = trans;
3397         return 0;
3398 
3399 out_drop:
3400         atomic_dec(&root->fs_info->open_ioctl_trans);
3401         mnt_drop_write_file(file);
3402 out:
3403         return ret;
3404 }
3405 
3406 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
3407 {
3408         struct inode *inode = file_inode(file);
3409         struct btrfs_root *root = BTRFS_I(inode)->root;
3410         struct btrfs_root *new_root;
3411         struct btrfs_dir_item *di;
3412         struct btrfs_trans_handle *trans;
3413         struct btrfs_path *path;
3414         struct btrfs_key location;
3415         struct btrfs_disk_key disk_key;
3416         u64 objectid = 0;
3417         u64 dir_id;
3418         int ret;
3419 
3420         if (!capable(CAP_SYS_ADMIN))
3421                 return -EPERM;
3422 
3423         ret = mnt_want_write_file(file);
3424         if (ret)
3425                 return ret;
3426 
3427         if (copy_from_user(&objectid, argp, sizeof(objectid))) {
3428                 ret = -EFAULT;
3429                 goto out;
3430         }
3431 
3432         if (!objectid)
3433                 objectid = BTRFS_FS_TREE_OBJECTID;
3434 
3435         location.objectid = objectid;
3436         location.type = BTRFS_ROOT_ITEM_KEY;
3437         location.offset = (u64)-1;
3438 
3439         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
3440         if (IS_ERR(new_root)) {
3441                 ret = PTR_ERR(new_root);
3442                 goto out;
3443         }
3444 
3445         path = btrfs_alloc_path();
3446         if (!path) {
3447                 ret = -ENOMEM;
3448                 goto out;
3449         }
3450         path->leave_spinning = 1;
3451 
3452         trans = btrfs_start_transaction(root, 1);
3453         if (IS_ERR(trans)) {
3454                 btrfs_free_path(path);
3455                 ret = PTR_ERR(trans);
3456                 goto out;
3457         }
3458 
3459         dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
3460         di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
3461                                    dir_id, "default", 7, 1);
3462         if (IS_ERR_OR_NULL(di)) {
3463                 btrfs_free_path(path);
3464                 btrfs_end_transaction(trans, root);
3465                 btrfs_err(new_root->fs_info, "Umm, you don't have the default dir"
3466                            "item, this isn't going to work");
3467                 ret = -ENOENT;
3468                 goto out;
3469         }
3470 
3471         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
3472         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
3473         btrfs_mark_buffer_dirty(path->nodes[0]);
3474         btrfs_free_path(path);
3475 
3476         btrfs_set_fs_incompat(root->fs_info, DEFAULT_SUBVOL);
3477         btrfs_end_transaction(trans, root);
3478 out:
3479         mnt_drop_write_file(file);
3480         return ret;
3481 }
3482 
3483 void btrfs_get_block_group_info(struct list_head *groups_list,
3484                                 struct btrfs_ioctl_space_info *space)
3485 {
3486         struct btrfs_block_group_cache *block_group;
3487 
3488         space->total_bytes = 0;
3489         space->used_bytes = 0;
3490         space->flags = 0;
3491         list_for_each_entry(block_group, groups_list, list) {
3492                 space->flags = block_group->flags;
3493                 space->total_bytes += block_group->key.offset;
3494                 space->used_bytes +=
3495                         btrfs_block_group_used(&block_group->item);
3496         }
3497 }
3498 
3499 static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
3500 {
3501         struct btrfs_ioctl_space_args space_args;
3502         struct btrfs_ioctl_space_info space;
3503         struct btrfs_ioctl_space_info *dest;
3504         struct btrfs_ioctl_space_info *dest_orig;
3505         struct btrfs_ioctl_space_info __user *user_dest;
3506         struct btrfs_space_info *info;
3507         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
3508                        BTRFS_BLOCK_GROUP_SYSTEM,
3509                        BTRFS_BLOCK_GROUP_METADATA,
3510                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
3511         int num_types = 4;
3512         int alloc_size;
3513         int ret = 0;
3514         u64 slot_count = 0;
3515         int i, c;
3516 
3517         if (copy_from_user(&space_args,
3518                            (struct btrfs_ioctl_space_args __user *)arg,
3519                            sizeof(space_args)))
3520                 return -EFAULT;
3521 
3522         for (i = 0; i < num_types; i++) {
3523                 struct btrfs_space_info *tmp;
3524 
3525                 info = NULL;
3526                 rcu_read_lock();
3527                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
3528                                         list) {
3529                         if (tmp->flags == types[i]) {
3530                                 info = tmp;
3531                                 break;
3532                         }
3533                 }
3534                 rcu_read_unlock();
3535 
3536                 if (!info)
3537                         continue;
3538 
3539                 down_read(&info->groups_sem);
3540                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3541                         if (!list_empty(&info->block_groups[c]))
3542                                 slot_count++;
3543                 }
3544                 up_read(&info->groups_sem);
3545         }
3546 
3547         /*
3548          * Global block reserve, exported as a space_info
3549          */
3550         slot_count++;
3551 
3552         /* space_slots == 0 means they are asking for a count */
3553         if (space_args.space_slots == 0) {
3554                 space_args.total_spaces = slot_count;
3555                 goto out;
3556         }
3557 
3558         slot_count = min_t(u64, space_args.space_slots, slot_count);
3559 
3560         alloc_size = sizeof(*dest) * slot_count;
3561 
3562         /* we generally have at most 6 or so space infos, one for each raid
3563          * level.  So, a whole page should be more than enough for everyone
3564          */
3565         if (alloc_size > PAGE_CACHE_SIZE)
3566                 return -ENOMEM;
3567 
3568         space_args.total_spaces = 0;
3569         dest = kmalloc(alloc_size, GFP_NOFS);
3570         if (!dest)
3571                 return -ENOMEM;
3572         dest_orig = dest;
3573 
3574         /* now we have a buffer to copy into */
3575         for (i = 0; i < num_types; i++) {
3576                 struct btrfs_space_info *tmp;
3577 
3578                 if (!slot_count)
3579                         break;
3580 
3581                 info = NULL;
3582                 rcu_read_lock();
3583                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
3584                                         list) {
3585                         if (tmp->flags == types[i]) {
3586                                 info = tmp;
3587                                 break;
3588                         }
3589                 }
3590                 rcu_read_unlock();
3591 
3592                 if (!info)
3593                         continue;
3594                 down_read(&info->groups_sem);
3595                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3596                         if (!list_empty(&info->block_groups[c])) {
3597                                 btrfs_get_block_group_info(
3598                                         &info->block_groups[c], &space);
3599                                 memcpy(dest, &space, sizeof(space));
3600                                 dest++;
3601                                 space_args.total_spaces++;
3602                                 slot_count--;
3603                         }
3604                         if (!slot_count)
3605                                 break;
3606                 }
3607                 up_read(&info->groups_sem);
3608         }
3609 
3610         /*
3611          * Add global block reserve
3612          */
3613         if (slot_count) {
3614                 struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv;
3615 
3616                 spin_lock(&block_rsv->lock);
3617                 space.total_bytes = block_rsv->size;
3618                 space.used_bytes = block_rsv->size - block_rsv->reserved;
3619                 spin_unlock(&block_rsv->lock);
3620                 space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
3621                 memcpy(dest, &space, sizeof(space));
3622                 space_args.total_spaces++;
3623         }
3624 
3625         user_dest = (struct btrfs_ioctl_space_info __user *)
3626                 (arg + sizeof(struct btrfs_ioctl_space_args));
3627 
3628         if (copy_to_user(user_dest, dest_orig, alloc_size))
3629                 ret = -EFAULT;
3630 
3631         kfree(dest_orig);
3632 out:
3633         if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
3634                 ret = -EFAULT;
3635 
3636         return ret;
3637 }
3638 
3639 /*
3640  * there are many ways the trans_start and trans_end ioctls can lead
3641  * to deadlocks.  They should only be used by applications that
3642  * basically own the machine, and have a very in depth understanding
3643  * of all the possible deadlocks and enospc problems.
3644  */
3645 long btrfs_ioctl_trans_end(struct file *file)
3646 {
3647         struct inode *inode = file_inode(file);
3648         struct btrfs_root *root = BTRFS_I(inode)->root;
3649         struct btrfs_trans_handle *trans;
3650 
3651         trans = file->private_data;
3652         if (!trans)
3653                 return -EINVAL;
3654         file->private_data = NULL;
3655 
3656         btrfs_end_transaction(trans, root);
3657 
3658         atomic_dec(&root->fs_info->open_ioctl_trans);
3659 
3660         mnt_drop_write_file(file);
3661         return 0;
3662 }
3663 
3664 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
3665                                             void __user *argp)
3666 {
3667         struct btrfs_trans_handle *trans;
3668         u64 transid;
3669         int ret;
3670 
3671         trans = btrfs_attach_transaction_barrier(root);
3672         if (IS_ERR(trans)) {
3673                 if (PTR_ERR(trans) != -ENOENT)
3674                         return PTR_ERR(trans);
3675 
3676                 /* No running transaction, don't bother */
3677                 transid = root->fs_info->last_trans_committed;
3678                 goto out;
3679         }
3680         transid = trans->transid;
3681         ret = btrfs_commit_transaction_async(trans, root, 0);
3682         if (ret) {
3683                 btrfs_end_transaction(trans, root);
3684                 return ret;
3685         }
3686 out:
3687         if (argp)
3688                 if (copy_to_user(argp, &transid, sizeof(transid)))
3689                         return -EFAULT;
3690         return 0;
3691 }
3692 
3693 static noinline long btrfs_ioctl_wait_sync(struct btrfs_root *root,
3694                                            void __user *argp)
3695 {
3696         u64 transid;
3697 
3698         if (argp) {
3699                 if (copy_from_user(&transid, argp, sizeof(transid)))
3700                         return -EFAULT;
3701         } else {
3702                 transid = 0;  /* current trans */
3703         }
3704         return btrfs_wait_for_commit(root, transid);
3705 }
3706 
3707 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
3708 {
3709         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
3710         struct btrfs_ioctl_scrub_args *sa;
3711         int ret;
3712 
3713         if (!capable(CAP_SYS_ADMIN))
3714                 return -EPERM;
3715 
3716         sa = memdup_user(arg, sizeof(*sa));
3717         if (IS_ERR(sa))
3718                 return PTR_ERR(sa);
3719 
3720         if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
3721                 ret = mnt_want_write_file(file);
3722                 if (ret)
3723                         goto out;
3724         }
3725 
3726         ret = btrfs_scrub_dev(root->fs_info, sa->devid, sa->start, sa->end,
3727                               &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
3728                               0);
3729 
3730         if (copy_to_user(arg, sa, sizeof(*sa)))
3731                 ret = -EFAULT;
3732 
3733         if (!(sa->flags & BTRFS_SCRUB_READONLY))
3734                 mnt_drop_write_file(file);
3735 out:
3736         kfree(sa);
3737         return ret;
3738 }
3739 
3740 static long btrfs_ioctl_scrub_cancel(struct btrfs_root *root, void __user *arg)
3741 {
3742         if (!capable(CAP_SYS_ADMIN))
3743                 return -EPERM;
3744 
3745         return btrfs_scrub_cancel(root->fs_info);
3746 }
3747 
3748 static long btrfs_ioctl_scrub_progress(struct btrfs_root *root,
3749                                        void __user *arg)
3750 {
3751         struct btrfs_ioctl_scrub_args *sa;
3752         int ret;
3753 
3754         if (!capable(CAP_SYS_ADMIN))
3755                 return -EPERM;
3756 
3757         sa = memdup_user(arg, sizeof(*sa));
3758         if (IS_ERR(sa))
3759                 return PTR_ERR(sa);
3760 
3761         ret = btrfs_scrub_progress(root, sa->devid, &sa->progress);
3762 
3763         if (copy_to_user(arg, sa, sizeof(*sa)))
3764                 ret = -EFAULT;
3765 
3766         kfree(sa);
3767         return ret;
3768 }
3769 
3770 static long btrfs_ioctl_get_dev_stats(struct btrfs_root *root,
3771                                       void __user *arg)
3772 {
3773         struct btrfs_ioctl_get_dev_stats *sa;
3774         int ret;
3775 
3776         sa = memdup_user(arg, sizeof(*sa));
3777         if (IS_ERR(sa))
3778                 return PTR_ERR(sa);
3779 
3780         if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
3781                 kfree(sa);
3782                 return -EPERM;
3783         }
3784 
3785         ret = btrfs_get_dev_stats(root, sa);
3786 
3787         if (copy_to_user(arg, sa, sizeof(*sa)))
3788                 ret = -EFAULT;
3789 
3790         kfree(sa);
3791         return ret;
3792 }
3793 
3794 static long btrfs_ioctl_dev_replace(struct btrfs_root *root, void __user *arg)
3795 {
3796         struct btrfs_ioctl_dev_replace_args *p;
3797         int ret;
3798 
3799         if (!capable(CAP_SYS_ADMIN))
3800                 return -EPERM;
3801 
3802         p = memdup_user(arg, sizeof(*p));
3803         if (IS_ERR(p))
3804                 return PTR_ERR(p);
3805 
3806         switch (p->cmd) {
3807         case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
3808                 if (root->fs_info->sb->s_flags & MS_RDONLY) {
3809                         ret = -EROFS;
3810                         goto out;
3811                 }
3812                 if (atomic_xchg(
3813                         &root->fs_info->mutually_exclusive_operation_running,
3814                         1)) {
3815                         ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3816                 } else {
3817                         ret = btrfs_dev_replace_start(root, p);
3818                         atomic_set(
3819                          &root->fs_info->mutually_exclusive_operation_running,
3820                          0);
3821                 }
3822                 break;
3823         case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
3824                 btrfs_dev_replace_status(root->fs_info, p);
3825                 ret = 0;
3826                 break;
3827         case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
3828                 ret = btrfs_dev_replace_cancel(root->fs_info, p);
3829                 break;
3830         default:
3831                 ret = -EINVAL;
3832                 break;
3833         }
3834 
3835         if (copy_to_user(arg, p, sizeof(*p)))
3836                 ret = -EFAULT;
3837 out:
3838         kfree(p);
3839         return ret;
3840 }
3841 
3842 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
3843 {
3844         int ret = 0;
3845         int i;
3846         u64 rel_ptr;
3847         int size;
3848         struct btrfs_ioctl_ino_path_args *ipa = NULL;
3849         struct inode_fs_paths *ipath = NULL;
3850         struct btrfs_path *path;
3851 
3852         if (!capable(CAP_DAC_READ_SEARCH))
3853                 return -EPERM;
3854 
3855         path = btrfs_alloc_path();
3856         if (!path) {
3857                 ret = -ENOMEM;
3858                 goto out;
3859         }
3860 
3861         ipa = memdup_user(arg, sizeof(*ipa));
3862         if (IS_ERR(ipa)) {
3863                 ret = PTR_ERR(ipa);
3864                 ipa = NULL;
3865                 goto out;
3866         }
3867 
3868         size = min_t(u32, ipa->size, 4096);
3869         ipath = init_ipath(size, root, path);
3870         if (IS_ERR(ipath)) {
3871                 ret = PTR_ERR(ipath);
3872                 ipath = NULL;
3873                 goto out;
3874         }
3875 
3876         ret = paths_from_inode(ipa->inum, ipath);
3877         if (ret < 0)
3878                 goto out;
3879 
3880         for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
3881                 rel_ptr = ipath->fspath->val[i] -
3882                           (u64)(unsigned long)ipath->fspath->val;
3883                 ipath->fspath->val[i] = rel_ptr;
3884         }
3885 
3886         ret = copy_to_user((void *)(unsigned long)ipa->fspath,
3887                            (void *)(unsigned long)ipath->fspath, size);
3888         if (ret) {
3889                 ret = -EFAULT;
3890                 goto out;
3891         }
3892 
3893 out:
3894         btrfs_free_path(path);
3895         free_ipath(ipath);
3896         kfree(ipa);
3897 
3898         return ret;
3899 }
3900 
3901 static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
3902 {
3903         struct btrfs_data_container *inodes = ctx;
3904         const size_t c = 3 * sizeof(u64);
3905 
3906         if (inodes->bytes_left >= c) {
3907                 inodes->bytes_left -= c;
3908                 inodes->val[inodes->elem_cnt] = inum;
3909                 inodes->val[inodes->elem_cnt + 1] = offset;
3910                 inodes->val[inodes->elem_cnt + 2] = root;
3911                 inodes->elem_cnt += 3;
3912         } else {
3913                 inodes->bytes_missing += c - inodes->bytes_left;
3914                 inodes->bytes_left = 0;
3915                 inodes->elem_missed += 3;
3916         }
3917 
3918         return 0;
3919 }
3920 
3921 static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
3922                                         void __user *arg)
3923 {
3924         int ret = 0;
3925         int size;
3926         struct btrfs_ioctl_logical_ino_args *loi;
3927         struct btrfs_data_container *inodes = NULL;
3928         struct btrfs_path *path = NULL;
3929 
3930         if (!capable(CAP_SYS_ADMIN))
3931                 return -EPERM;
3932 
3933         loi = memdup_user(arg, sizeof(*loi));
3934         if (IS_ERR(loi)) {
3935                 ret = PTR_ERR(loi);
3936                 loi = NULL;
3937                 goto out;
3938         }
3939 
3940         path = btrfs_alloc_path();
3941         if (!path) {
3942                 ret = -ENOMEM;
3943                 goto out;
3944         }
3945 
3946         size = min_t(u32, loi->size, 64 * 1024);
3947         inodes = init_data_container(size);
3948         if (IS_ERR(inodes)) {
3949                 ret = PTR_ERR(inodes);
3950                 inodes = NULL;
3951                 goto out;
3952         }
3953 
3954         ret = iterate_inodes_from_logical(loi->logical, root->fs_info, path,
3955                                           build_ino_list, inodes);
3956         if (ret == -EINVAL)
3957                 ret = -ENOENT;
3958         if (ret < 0)
3959                 goto out;
3960 
3961         ret = copy_to_user((void *)(unsigned long)loi->inodes,
3962                            (void *)(unsigned long)inodes, size);
3963         if (ret)
3964                 ret = -EFAULT;
3965 
3966 out:
3967         btrfs_free_path(path);
3968         vfree(inodes);
3969         kfree(loi);
3970 
3971         return ret;
3972 }
3973 
3974 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
3975                                struct btrfs_ioctl_balance_args *bargs)
3976 {
3977         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3978 
3979         bargs->flags = bctl->flags;
3980 
3981         if (atomic_read(&fs_info->balance_running))
3982                 bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
3983         if (atomic_read(&fs_info->balance_pause_req))
3984                 bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
3985         if (atomic_read(&fs_info->balance_cancel_req))
3986                 bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
3987 
3988         memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
3989         memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
3990         memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
3991 
3992         if (lock) {
3993                 spin_lock(&fs_info->balance_lock);
3994                 memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
3995                 spin_unlock(&fs_info->balance_lock);
3996         } else {
3997                 memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
3998         }
3999 }
4000 
4001 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
4002 {
4003         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4004         struct btrfs_fs_info *fs_info = root->fs_info;
4005         struct btrfs_ioctl_balance_args *bargs;
4006         struct btrfs_balance_control *bctl;
4007         bool need_unlock; /* for mut. excl. ops lock */
4008         int ret;
4009 
4010         if (!capable(CAP_SYS_ADMIN))
4011                 return -EPERM;
4012 
4013         ret = mnt_want_write_file(file);
4014         if (ret)
4015                 return ret;
4016 
4017 again:
4018         if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
4019                 mutex_lock(&fs_info->volume_mutex);
4020                 mutex_lock(&fs_info->balance_mutex);
4021                 need_unlock = true;
4022                 goto locked;
4023         }
4024 
4025         /*
4026          * mut. excl. ops lock is locked.  Three possibilites:
4027          *   (1) some other op is running
4028          *   (2) balance is running
4029          *   (3) balance is paused -- special case (think resume)
4030          */
4031         mutex_lock(&fs_info->balance_mutex);
4032         if (fs_info->balance_ctl) {
4033                 /* this is either (2) or (3) */
4034                 if (!atomic_read(&fs_info->balance_running)) {
4035                         mutex_unlock(&fs_info->balance_mutex);
4036                         if (!mutex_trylock(&fs_info->volume_mutex))
4037                                 goto again;
4038                         mutex_lock(&fs_info->balance_mutex);
4039 
4040                         if (fs_info->balance_ctl &&
4041                             !atomic_read(&fs_info->balance_running)) {
4042                                 /* this is (3) */
4043                                 need_unlock = false;
4044                                 goto locked;
4045                         }
4046 
4047                         mutex_unlock(&fs_info->balance_mutex);
4048                         mutex_unlock(&fs_info->volume_mutex);
4049                         goto again;
4050                 } else {
4051                         /* this is (2) */
4052                         mutex_unlock(&fs_info->balance_mutex);
4053                         ret = -EINPROGRESS;
4054                         goto out;
4055                 }
4056         } else {
4057                 /* this is (1) */
4058                 mutex_unlock(&fs_info->balance_mutex);
4059                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4060                 goto out;
4061         }
4062 
4063 locked:
4064         BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));
4065 
4066         if (arg) {
4067                 bargs = memdup_user(arg, sizeof(*bargs));
4068                 if (IS_ERR(bargs)) {
4069                         ret = PTR_ERR(bargs);
4070                         goto out_unlock;
4071                 }
4072 
4073                 if (bargs->flags & BTRFS_BALANCE_RESUME) {
4074                         if (!fs_info->balance_ctl) {
4075                                 ret = -ENOTCONN;
4076                                 goto out_bargs;
4077                         }
4078 
4079                         bctl = fs_info->balance_ctl;
4080                         spin_lock(&fs_info->balance_lock);
4081                         bctl->flags |= BTRFS_BALANCE_RESUME;
4082                         spin_unlock(&fs_info->balance_lock);
4083 
4084                         goto do_balance;
4085                 }
4086         } else {
4087                 bargs = NULL;
4088         }
4089 
4090         if (fs_info->balance_ctl) {
4091                 ret = -EINPROGRESS;
4092                 goto out_bargs;
4093         }
4094 
4095         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
4096         if (!bctl) {
4097                 ret = -ENOMEM;
4098                 goto out_bargs;
4099         }
4100 
4101         bctl->fs_info = fs_info;
4102         if (arg) {
4103                 memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
4104                 memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
4105                 memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
4106 
4107                 bctl->flags = bargs->flags;
4108         } else {
4109                 /* balance everything - no filters */
4110                 bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
4111         }
4112 
4113 do_balance:
4114         /*
4115          * Ownership of bctl and mutually_exclusive_operation_running
4116          * goes to to btrfs_balance.  bctl is freed in __cancel_balance,
4117          * or, if restriper was paused all the way until unmount, in
4118          * free_fs_info.  mutually_exclusive_operation_running is
4119          * cleared in __cancel_balance.
4120          */
4121         need_unlock = false;
4122 
4123         ret = btrfs_balance(bctl, bargs);
4124 
4125         if (arg) {
4126                 if (copy_to_user(arg, bargs, sizeof(*bargs)))
4127                         ret = -EFAULT;
4128         }
4129 
4130 out_bargs:
4131         kfree(bargs);
4132 out_unlock:
4133         mutex_unlock(&fs_info->balance_mutex);
4134         mutex_unlock(&fs_info->volume_mutex);
4135         if (need_unlock)
4136                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
4137 out:
4138         mnt_drop_write_file(file);
4139         return ret;
4140 }
4141 
4142 static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd)
4143 {
4144         if (!capable(CAP_SYS_ADMIN))
4145                 return -EPERM;
4146 
4147         switch (cmd) {
4148         case BTRFS_BALANCE_CTL_PAUSE:
4149                 return btrfs_pause_balance(root->fs_info);
4150         case BTRFS_BALANCE_CTL_CANCEL:
4151                 return btrfs_cancel_balance(root->fs_info);
4152         }
4153 
4154         return -EINVAL;
4155 }
4156 
4157 static long btrfs_ioctl_balance_progress(struct btrfs_root *root,
4158                                          void __user *arg)
4159 {
4160         struct btrfs_fs_info *fs_info = root->fs_info;
4161         struct btrfs_ioctl_balance_args *bargs;
4162         int ret = 0;
4163 
4164         if (!capable(CAP_SYS_ADMIN))
4165                 return -EPERM;
4166 
4167         mutex_lock(&fs_info->balance_mutex);
4168         if (!fs_info->balance_ctl) {
4169                 ret = -ENOTCONN;
4170                 goto out;
4171         }
4172 
4173         bargs = kzalloc(sizeof(*bargs), GFP_NOFS);
4174         if (!bargs) {
4175                 ret = -ENOMEM;
4176                 goto out;
4177         }
4178 
4179         update_ioctl_balance_args(fs_info, 1, bargs);
4180 
4181         if (copy_to_user(arg, bargs, sizeof(*bargs)))
4182                 ret = -EFAULT;
4183 
4184         kfree(bargs);
4185 out:
4186         mutex_unlock(&fs_info->balance_mutex);
4187         return ret;
4188 }
4189 
4190 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
4191 {
4192         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4193         struct btrfs_ioctl_quota_ctl_args *sa;
4194         struct btrfs_trans_handle *trans = NULL;
4195         int ret;
4196         int err;
4197 
4198         if (!capable(CAP_SYS_ADMIN))
4199                 return -EPERM;
4200 
4201         ret = mnt_want_write_file(file);
4202         if (ret)
4203                 return ret;
4204 
4205         sa = memdup_user(arg, sizeof(*sa));
4206         if (IS_ERR(sa)) {
4207                 ret = PTR_ERR(sa);
4208                 goto drop_write;
4209         }
4210 
4211         down_write(&root->fs_info->subvol_sem);
4212         trans = btrfs_start_transaction(root->fs_info->tree_root, 2);
4213         if (IS_ERR(trans)) {
4214                 ret = PTR_ERR(trans);
4215                 goto out;
4216         }
4217 
4218         switch (sa->cmd) {
4219         case BTRFS_QUOTA_CTL_ENABLE:
4220                 ret = btrfs_quota_enable(trans, root->fs_info);
4221                 break;
4222         case BTRFS_QUOTA_CTL_DISABLE:
4223                 ret = btrfs_quota_disable(trans, root->fs_info);
4224                 break;
4225         default:
4226                 ret = -EINVAL;
4227                 break;
4228         }
4229 
4230         err = btrfs_commit_transaction(trans, root->fs_info->tree_root);
4231         if (err && !ret)
4232                 ret = err;
4233 out:
4234         kfree(sa);
4235         up_write(&root->fs_info->subvol_sem);
4236 drop_write:
4237         mnt_drop_write_file(file);
4238         return ret;
4239 }
4240 
4241 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
4242 {
4243         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4244         struct btrfs_ioctl_qgroup_assign_args *sa;
4245         struct btrfs_trans_handle *trans;
4246         int ret;
4247         int err;
4248 
4249         if (!capable(CAP_SYS_ADMIN))
4250                 return -EPERM;
4251 
4252         ret = mnt_want_write_file(file);
4253         if (ret)
4254                 return ret;
4255 
4256         sa = memdup_user(arg, sizeof(*sa));
4257         if (IS_ERR(sa)) {
4258                 ret = PTR_ERR(sa);
4259                 goto drop_write;
4260         }
4261 
4262         trans = btrfs_join_transaction(root);
4263         if (IS_ERR(trans)) {
4264                 ret = PTR_ERR(trans);
4265                 goto out;
4266         }
4267 
4268         /* FIXME: check if the IDs really exist */
4269         if (sa->assign) {
4270                 ret = btrfs_add_qgroup_relation(trans, root->fs_info,
4271                                                 sa->src, sa->dst);
4272         } else {
4273                 ret = btrfs_del_qgroup_relation(trans, root->fs_info,
4274                                                 sa->src, sa->dst);
4275         }
4276 
4277         err = btrfs_end_transaction(trans, root);
4278         if (err && !ret)
4279                 ret = err;
4280 
4281 out:
4282         kfree(sa);
4283 drop_write:
4284         mnt_drop_write_file(file);
4285         return ret;
4286 }
4287 
4288 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
4289 {
4290         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4291         struct btrfs_ioctl_qgroup_create_args *sa;
4292         struct btrfs_trans_handle *trans;
4293         int ret;
4294         int err;
4295 
4296         if (!capable(CAP_SYS_ADMIN))
4297                 return -EPERM;
4298 
4299         ret = mnt_want_write_file(file);
4300         if (ret)
4301                 return ret;
4302 
4303         sa = memdup_user(arg, sizeof(*sa));
4304         if (IS_ERR(sa)) {
4305                 ret = PTR_ERR(sa);
4306                 goto drop_write;
4307         }
4308 
4309         if (!sa->qgroupid) {
4310                 ret = -EINVAL;
4311                 goto out;
4312         }
4313 
4314         trans = btrfs_join_transaction(root);
4315         if (IS_ERR(trans)) {
4316                 ret = PTR_ERR(trans);
4317                 goto out;
4318         }
4319 
4320         /* FIXME: check if the IDs really exist */
4321         if (sa->create) {
4322                 ret = btrfs_create_qgroup(trans, root->fs_info, sa->qgroupid,
4323                                           NULL);
4324         } else {
4325                 ret = btrfs_remove_qgroup(trans, root->fs_info, sa->qgroupid);
4326         }
4327 
4328         err = btrfs_end_transaction(trans, root);
4329         if (err && !ret)
4330                 ret = err;
4331 
4332 out:
4333         kfree(sa);
4334 drop_write:
4335         mnt_drop_write_file(file);
4336         return ret;
4337 }
4338 
4339 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
4340 {
4341         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4342         struct btrfs_ioctl_qgroup_limit_args *sa;
4343         struct btrfs_trans_handle *trans;
4344         int ret;
4345         int err;
4346         u64 qgroupid;
4347 
4348         if (!capable(CAP_SYS_ADMIN))
4349                 return -EPERM;
4350 
4351         ret = mnt_want_write_file(file);
4352         if (ret)
4353                 return ret;
4354 
4355         sa = memdup_user(arg, sizeof(*sa));
4356         if (IS_ERR(sa)) {
4357                 ret = PTR_ERR(sa);
4358                 goto drop_write;
4359         }
4360 
4361         trans = btrfs_join_transaction(root);
4362         if (IS_ERR(trans)) {
4363                 ret = PTR_ERR(trans);
4364                 goto out;
4365         }
4366 
4367         qgroupid = sa->qgroupid;
4368         if (!qgroupid) {
4369                 /* take the current subvol as qgroup */
4370                 qgroupid = root->root_key.objectid;
4371         }
4372 
4373         /* FIXME: check if the IDs really exist */
4374         ret = btrfs_limit_qgroup(trans, root->fs_info, qgroupid, &sa->lim);
4375 
4376         err = btrfs_end_transaction(trans, root);
4377         if (err && !ret)
4378                 ret = err;
4379 
4380 out:
4381         kfree(sa);
4382 drop_write:
4383         mnt_drop_write_file(file);
4384         return ret;
4385 }
4386 
4387 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
4388 {
4389         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4390         struct btrfs_ioctl_quota_rescan_args *qsa;
4391         int ret;
4392 
4393         if (!capable(CAP_SYS_ADMIN))
4394                 return -EPERM;
4395 
4396         ret = mnt_want_write_file(file);
4397         if (ret)
4398                 return ret;
4399 
4400         qsa = memdup_user(arg, sizeof(*qsa));
4401         if (IS_ERR(qsa)) {
4402                 ret = PTR_ERR(qsa);
4403                 goto drop_write;
4404         }
4405 
4406         if (qsa->flags) {
4407                 ret = -EINVAL;
4408                 goto out;
4409         }
4410 
4411         ret = btrfs_qgroup_rescan(root->fs_info);
4412 
4413 out:
4414         kfree(qsa);
4415 drop_write:
4416         mnt_drop_write_file(file);
4417         return ret;
4418 }
4419 
4420 static long btrfs_ioctl_quota_rescan_status(struct file *file, void __user *arg)
4421 {
4422         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4423         struct btrfs_ioctl_quota_rescan_args *qsa;
4424         int ret = 0;
4425 
4426         if (!capable(CAP_SYS_ADMIN))
4427                 return -EPERM;
4428 
4429         qsa = kzalloc(sizeof(*qsa), GFP_NOFS);
4430         if (!qsa)
4431                 return -ENOMEM;
4432 
4433         if (root->fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
4434                 qsa->flags = 1;
4435                 qsa->progress = root->fs_info->qgroup_rescan_progress.objectid;
4436         }
4437 
4438         if (copy_to_user(arg, qsa, sizeof(*qsa)))
4439                 ret = -EFAULT;
4440 
4441         kfree(qsa);
4442         return ret;
4443 }
4444 
4445 static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg)
4446 {
4447         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4448 
4449         if (!capable(CAP_SYS_ADMIN))
4450                 return -EPERM;
4451 
4452         return btrfs_qgroup_wait_for_completion(root->fs_info);
4453 }
4454 
4455 static long _btrfs_ioctl_set_received_subvol(struct file *file,
4456                                             struct btrfs_ioctl_received_subvol_args *sa)
4457 {
4458         struct inode *inode = file_inode(file);
4459         struct btrfs_root *root = BTRFS_I(inode)->root;
4460         struct btrfs_root_item *root_item = &root->root_item;
4461         struct btrfs_trans_handle *trans;
4462         struct timespec ct = CURRENT_TIME;
4463         int ret = 0;
4464         int received_uuid_changed;
4465 
4466         if (!inode_owner_or_capable(inode))
4467                 return -EPERM;
4468 
4469         ret = mnt_want_write_file(file);
4470         if (ret < 0)
4471                 return ret;
4472 
4473         down_write(&root->fs_info->subvol_sem);
4474 
4475         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
4476                 ret = -EINVAL;
4477                 goto out;
4478         }
4479 
4480         if (btrfs_root_readonly(root)) {
4481                 ret = -EROFS;
4482                 goto out;
4483         }
4484 
4485         /*
4486          * 1 - root item
4487          * 2 - uuid items (received uuid + subvol uuid)
4488          */
4489         trans = btrfs_start_transaction(root, 3);
4490         if (IS_ERR(trans)) {
4491                 ret = PTR_ERR(trans);
4492                 trans = NULL;
4493                 goto out;
4494         }
4495 
4496         sa->rtransid = trans->transid;
4497         sa->rtime.sec = ct.tv_sec;
4498         sa->rtime.nsec = ct.tv_nsec;
4499 
4500         received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
4501                                        BTRFS_UUID_SIZE);
4502         if (received_uuid_changed &&
4503             !btrfs_is_empty_uuid(root_item->received_uuid))
4504                 btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
4505                                     root_item->received_uuid,
4506                                     BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4507                                     root->root_key.objectid);
4508         memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
4509         btrfs_set_root_stransid(root_item, sa->stransid);
4510         btrfs_set_root_rtransid(root_item, sa->rtransid);
4511         btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
4512         btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
4513         btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
4514         btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
4515 
4516         ret = btrfs_update_root(trans, root->fs_info->tree_root,
4517                                 &root->root_key, &root->root_item);
4518         if (ret < 0) {
4519                 btrfs_end_transaction(trans, root);
4520                 goto out;
4521         }
4522         if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
4523                 ret = btrfs_uuid_tree_add(trans, root->fs_info->uuid_root,
4524                                           sa->uuid,
4525                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4526                                           root->root_key.objectid);
4527                 if (ret < 0 && ret != -EEXIST) {
4528                         btrfs_abort_transaction(trans, root, ret);
4529                         goto out;
4530                 }
4531         }
4532         ret = btrfs_commit_transaction(trans, root);
4533         if (ret < 0) {
4534                 btrfs_abort_transaction(trans, root, ret);
4535                 goto out;
4536         }
4537 
4538 out:
4539         up_write(&root->fs_info->subvol_sem);
4540         mnt_drop_write_file(file);
4541         return ret;
4542 }
4543 
4544 #ifdef CONFIG_64BIT
4545 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
4546                                                 void __user *arg)
4547 {
4548         struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
4549         struct btrfs_ioctl_received_subvol_args *args64 = NULL;
4550         int ret = 0;
4551 
4552         args32 = memdup_user(arg, sizeof(*args32));
4553         if (IS_ERR(args32)) {
4554                 ret = PTR_ERR(args32);
4555                 args32 = NULL;
4556                 goto out;
4557         }
4558 
4559         args64 = kmalloc(sizeof(*args64), GFP_NOFS);
4560         if (!args64) {
4561                 ret = -ENOMEM;
4562                 goto out;
4563         }
4564 
4565         memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
4566         args64->stransid = args32->stransid;
4567         args64->rtransid = args32->rtransid;
4568         args64->stime.sec = args32->stime.sec;
4569         args64->stime.nsec = args32->stime.nsec;
4570         args64->rtime.sec = args32->rtime.sec;
4571         args64->rtime.nsec = args32->rtime.nsec;
4572         args64->flags = args32->flags;
4573 
4574         ret = _btrfs_ioctl_set_received_subvol(file, args64);
4575         if (ret)
4576                 goto out;
4577 
4578         memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
4579         args32->stransid = args64->stransid;
4580         args32->rtransid = args64->rtransid;
4581         args32->stime.sec = args64->stime.sec;
4582         args32->stime.nsec = args64->stime.nsec;
4583         args32->rtime.sec = args64->rtime.sec;
4584         args32->rtime.nsec = args64->rtime.nsec;
4585         args32->flags = args64->flags;
4586 
4587         ret = copy_to_user(arg, args32, sizeof(*args32));
4588         if (ret)
4589                 ret = -EFAULT;
4590 
4591 out:
4592         kfree(args32);
4593         kfree(args64);
4594         return ret;
4595 }
4596 #endif
4597 
4598 static long btrfs_ioctl_set_received_subvol(struct file *file,
4599                                             void __user *arg)
4600 {
4601         struct btrfs_ioctl_received_subvol_args *sa = NULL;
4602         int ret = 0;
4603 
4604         sa = memdup_user(arg, sizeof(*sa));
4605         if (IS_ERR(sa)) {
4606                 ret = PTR_ERR(sa);
4607                 sa = NULL;
4608                 goto out;
4609         }
4610 
4611         ret = _btrfs_ioctl_set_received_subvol(file, sa);
4612 
4613         if (ret)
4614                 goto out;
4615 
4616         ret = copy_to_user(arg, sa, sizeof(*sa));
4617         if (ret)
4618                 ret = -EFAULT;
4619 
4620 out:
4621         kfree(sa);
4622         return ret;
4623 }
4624 
4625 static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
4626 {
4627         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4628         size_t len;
4629         int ret;
4630         char label[BTRFS_LABEL_SIZE];
4631 
4632         spin_lock(&root->fs_info->super_lock);
4633         memcpy(label, root->fs_info->super_copy->label, BTRFS_LABEL_SIZE);
4634         spin_unlock(&root->fs_info->super_lock);
4635 
4636         len = strnlen(label, BTRFS_LABEL_SIZE);
4637 
4638         if (len == BTRFS_LABEL_SIZE) {
4639                 btrfs_warn(root->fs_info,
4640                         "label is too long, return the first %zu bytes", --len);
4641         }
4642 
4643         ret = copy_to_user(arg, label, len);
4644 
4645         return ret ? -EFAULT : 0;
4646 }
4647 
4648 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
4649 {
4650         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4651         struct btrfs_super_block *super_block = root->fs_info->super_copy;
4652         struct btrfs_trans_handle *trans;
4653         char label[BTRFS_LABEL_SIZE];
4654         int ret;
4655 
4656         if (!capable(CAP_SYS_ADMIN))
4657                 return -EPERM;
4658 
4659         if (copy_from_user(label, arg, sizeof(label)))
4660                 return -EFAULT;
4661 
4662         if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
4663                 btrfs_err(root->fs_info, "unable to set label with more than %d bytes",
4664                        BTRFS_LABEL_SIZE - 1);
4665                 return -EINVAL;
4666         }
4667 
4668         ret = mnt_want_write_file(file);
4669         if (ret)
4670                 return ret;
4671 
4672         trans = btrfs_start_transaction(root, 0);
4673         if (IS_ERR(trans)) {
4674                 ret = PTR_ERR(trans);
4675                 goto out_unlock;
4676         }
4677 
4678         spin_lock(&root->fs_info->super_lock);
4679         strcpy(super_block->label, label);
4680         spin_unlock(&root->fs_info->super_lock);
4681         ret = btrfs_commit_transaction(trans, root);
4682 
4683 out_unlock:
4684         mnt_drop_write_file(file);
4685         return ret;
4686 }
4687 
4688 #define INIT_FEATURE_FLAGS(suffix) \
4689         { .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
4690           .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
4691           .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
4692 
4693 static int btrfs_ioctl_get_supported_features(struct file *file,
4694                                               void __user *arg)
4695 {
4696         static struct btrfs_ioctl_feature_flags features[3] = {
4697                 INIT_FEATURE_FLAGS(SUPP),
4698                 INIT_FEATURE_FLAGS(SAFE_SET),
4699                 INIT_FEATURE_FLAGS(SAFE_CLEAR)
4700         };
4701 
4702         if (copy_to_user(arg, &features, sizeof(features)))
4703                 return -EFAULT;
4704 
4705         return 0;
4706 }
4707 
4708 static int btrfs_ioctl_get_features(struct file *file, void __user *arg)
4709 {
4710         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4711         struct btrfs_super_block *super_block = root->fs_info->super_copy;
4712         struct btrfs_ioctl_feature_flags features;
4713 
4714         features.compat_flags = btrfs_super_compat_flags(super_block);
4715         features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
4716         features.incompat_flags = btrfs_super_incompat_flags(super_block);
4717 
4718         if (copy_to_user(arg, &features, sizeof(features)))
4719                 return -EFAULT;
4720 
4721         return 0;
4722 }
4723 
4724 static int check_feature_bits(struct btrfs_root *root,
4725                               enum btrfs_feature_set set,
4726                               u64 change_mask, u64 flags, u64 supported_flags,
4727                               u64 safe_set, u64 safe_clear)
4728 {
4729         const char *type = btrfs_feature_set_names[set];
4730         char *names;
4731         u64 disallowed, unsupported;
4732         u64 set_mask = flags & change_mask;
4733         u64 clear_mask = ~flags & change_mask;
4734 
4735         unsupported = set_mask & ~supported_flags;
4736         if (unsupported) {
4737                 names = btrfs_printable_features(set, unsupported);
4738                 if (names) {
4739                         btrfs_warn(root->fs_info,
4740                            "this kernel does not support the %s feature bit%s",
4741                            names, strchr(names, ',') ? "s" : "");
4742                         kfree(names);
4743                 } else
4744                         btrfs_warn(root->fs_info,
4745                            "this kernel does not support %s bits 0x%llx",
4746                            type, unsupported);
4747                 return -EOPNOTSUPP;
4748         }
4749 
4750         disallowed = set_mask & ~safe_set;
4751         if (disallowed) {
4752                 names = btrfs_printable_features(set, disallowed);
4753                 if (names) {
4754                         btrfs_warn(root->fs_info,
4755                            "can't set the %s feature bit%s while mounted",
4756                            names, strchr(names, ',') ? "s" : "");
4757                         kfree(names);
4758                 } else
4759                         btrfs_warn(root->fs_info,
4760                            "can't set %s bits 0x%llx while mounted",
4761                            type, disallowed);
4762                 return -EPERM;
4763         }
4764 
4765         disallowed = clear_mask & ~safe_clear;
4766         if (disallowed) {
4767                 names = btrfs_printable_features(set, disallowed);
4768                 if (names) {
4769                         btrfs_warn(root->fs_info,
4770                            "can't clear the %s feature bit%s while mounted",
4771                            names, strchr(names, ',') ? "s" : "");
4772                         kfree(names);
4773                 } else
4774                         btrfs_warn(root->fs_info,
4775                            "can't clear %s bits 0x%llx while mounted",
4776                            type, disallowed);
4777                 return -EPERM;
4778         }
4779 
4780         return 0;
4781 }
4782 
4783 #define check_feature(root, change_mask, flags, mask_base)      \
4784 check_feature_bits(root, FEAT_##mask_base, change_mask, flags,  \
4785                    BTRFS_FEATURE_ ## mask_base ## _SUPP,        \
4786                    BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,    \
4787                    BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
4788 
4789 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
4790 {
4791         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4792         struct btrfs_super_block *super_block = root->fs_info->super_copy;
4793         struct btrfs_ioctl_feature_flags flags[2];
4794         struct btrfs_trans_handle *trans;
4795         u64 newflags;
4796         int ret;
4797 
4798         if (!capable(CAP_SYS_ADMIN))
4799                 return -EPERM;
4800 
4801         if (copy_from_user(flags, arg, sizeof(flags)))
4802                 return -EFAULT;
4803 
4804         /* Nothing to do */
4805         if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
4806             !flags[0].incompat_flags)
4807                 return 0;
4808 
4809         ret = check_feature(root, flags[0].compat_flags,
4810                             flags[1].compat_flags, COMPAT);
4811         if (ret)
4812                 return ret;
4813 
4814         ret = check_feature(root, flags[0].compat_ro_flags,
4815                             flags[1].compat_ro_flags, COMPAT_RO);
4816         if (ret)
4817                 return ret;
4818 
4819         ret = check_feature(root, flags[0].incompat_flags,
4820                             flags[1].incompat_flags, INCOMPAT);
4821         if (ret)
4822                 return ret;
4823 
4824         trans = btrfs_start_transaction(root, 0);
4825         if (IS_ERR(trans))
4826                 return PTR_ERR(trans);
4827 
4828         spin_lock(&root->fs_info->super_lock);
4829         newflags = btrfs_super_compat_flags(super_block);
4830         newflags |= flags[0].compat_flags & flags[1].compat_flags;
4831         newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
4832         btrfs_set_super_compat_flags(super_block, newflags);
4833 
4834         newflags = btrfs_super_compat_ro_flags(super_block);
4835         newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
4836         newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
4837         btrfs_set_super_compat_ro_flags(super_block, newflags);
4838 
4839         newflags = btrfs_super_incompat_flags(super_block);
4840         newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
4841         newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
4842         btrfs_set_super_incompat_flags(super_block, newflags);
4843         spin_unlock(&root->fs_info->super_lock);
4844 
4845         return btrfs_commit_transaction(trans, root);
4846 }
4847 
4848 long btrfs_ioctl(struct file *file, unsigned int
4849                 cmd, unsigned long arg)
4850 {
4851         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4852         void __user *argp = (void __user *)arg;
4853 
4854         switch (cmd) {
4855         case FS_IOC_GETFLAGS:
4856                 return btrfs_ioctl_getflags(file, argp);
4857         case FS_IOC_SETFLAGS:
4858                 return btrfs_ioctl_setflags(file, argp);
4859         case FS_IOC_GETVERSION:
4860                 return btrfs_ioctl_getversion(file, argp);
4861         case FITRIM:
4862                 return btrfs_ioctl_fitrim(file, argp);
4863         case BTRFS_IOC_SNAP_CREATE:
4864                 return btrfs_ioctl_snap_create(file, argp, 0);
4865         case BTRFS_IOC_SNAP_CREATE_V2:
4866                 return btrfs_ioctl_snap_create_v2(file, argp, 0);
4867         case BTRFS_IOC_SUBVOL_CREATE:
4868                 return btrfs_ioctl_snap_create(file, argp, 1);
4869         case BTRFS_IOC_SUBVOL_CREATE_V2:
4870                 return btrfs_ioctl_snap_create_v2(file, argp, 1);
4871         case BTRFS_IOC_SNAP_DESTROY:
4872                 return btrfs_ioctl_snap_destroy(file, argp);
4873         case BTRFS_IOC_SUBVOL_GETFLAGS:
4874                 return btrfs_ioctl_subvol_getflags(file, argp);
4875         case BTRFS_IOC_SUBVOL_SETFLAGS:
4876                 return btrfs_ioctl_subvol_setflags(file, argp);
4877         case BTRFS_IOC_DEFAULT_SUBVOL:
4878                 return btrfs_ioctl_default_subvol(file, argp);
4879         case BTRFS_IOC_DEFRAG:
4880                 return btrfs_ioctl_defrag(file, NULL);
4881         case BTRFS_IOC_DEFRAG_RANGE:
4882                 return btrfs_ioctl_defrag(file, argp);
4883         case BTRFS_IOC_RESIZE:
4884                 return btrfs_ioctl_resize(file, argp);
4885         case BTRFS_IOC_ADD_DEV:
4886                 return btrfs_ioctl_add_dev(root, argp);
4887         case BTRFS_IOC_RM_DEV:
4888                 return btrfs_ioctl_rm_dev(file, argp);
4889         case BTRFS_IOC_FS_INFO:
4890                 return btrfs_ioctl_fs_info(root, argp);
4891         case BTRFS_IOC_DEV_INFO:
4892                 return btrfs_ioctl_dev_info(root, argp);
4893         case BTRFS_IOC_BALANCE:
4894                 return btrfs_ioctl_balance(file, NULL);
4895         case BTRFS_IOC_CLONE:
4896                 return btrfs_ioctl_clone(file, arg, 0, 0, 0);
4897         case BTRFS_IOC_CLONE_RANGE:
4898                 return btrfs_ioctl_clone_range(file, argp);
4899         case BTRFS_IOC_TRANS_START:
4900                 return btrfs_ioctl_trans_start(file);
4901         case BTRFS_IOC_TRANS_END:
4902                 return btrfs_ioctl_trans_end(file);
4903         case BTRFS_IOC_TREE_SEARCH:
4904                 return btrfs_ioctl_tree_search(file, argp);
4905         case BTRFS_IOC_INO_LOOKUP:
4906                 return btrfs_ioctl_ino_lookup(file, argp);
4907         case BTRFS_IOC_INO_PATHS:
4908                 return btrfs_ioctl_ino_to_path(root, argp);
4909         case BTRFS_IOC_LOGICAL_INO:
4910                 return btrfs_ioctl_logical_to_ino(root, argp);
4911         case BTRFS_IOC_SPACE_INFO:
4912                 return btrfs_ioctl_space_info(root, argp);
4913         case BTRFS_IOC_SYNC: {
4914                 int ret;
4915 
4916                 ret = btrfs_start_delalloc_roots(root->fs_info, 0, -1);
4917                 if (ret)
4918                         return ret;
4919                 ret = btrfs_sync_fs(file->f_dentry->d_sb, 1);
4920                 return ret;
4921         }
4922         case BTRFS_IOC_START_SYNC:
4923                 return btrfs_ioctl_start_sync(root, argp);
4924         case BTRFS_IOC_WAIT_SYNC:
4925                 return btrfs_ioctl_wait_sync(root, argp);
4926         case BTRFS_IOC_SCRUB:
4927                 return btrfs_ioctl_scrub(file, argp);
4928         case BTRFS_IOC_SCRUB_CANCEL:
4929                 return btrfs_ioctl_scrub_cancel(root, argp);
4930         case BTRFS_IOC_SCRUB_PROGRESS:
4931                 return btrfs_ioctl_scrub_progress(root, argp);
4932         case BTRFS_IOC_BALANCE_V2:
4933                 return btrfs_ioctl_balance(file, argp);
4934         case BTRFS_IOC_BALANCE_CTL:
4935                 return btrfs_ioctl_balance_ctl(root, arg);
4936         case BTRFS_IOC_BALANCE_PROGRESS:
4937                 return btrfs_ioctl_balance_progress(root, argp);
4938         case BTRFS_IOC_SET_RECEIVED_SUBVOL:
4939                 return btrfs_ioctl_set_received_subvol(file, argp);
4940 #ifdef CONFIG_64BIT
4941         case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
4942                 return btrfs_ioctl_set_received_subvol_32(file, argp);
4943 #endif
4944         case BTRFS_IOC_SEND:
4945                 return btrfs_ioctl_send(file, argp);
4946         case BTRFS_IOC_GET_DEV_STATS:
4947                 return btrfs_ioctl_get_dev_stats(root, argp);
4948         case BTRFS_IOC_QUOTA_CTL:
4949                 return btrfs_ioctl_quota_ctl(file, argp);
4950         case BTRFS_IOC_QGROUP_ASSIGN:
4951                 return btrfs_ioctl_qgroup_assign(file, argp);
4952         case BTRFS_IOC_QGROUP_CREATE:
4953                 return btrfs_ioctl_qgroup_create(file, argp);
4954         case BTRFS_IOC_QGROUP_LIMIT:
4955                 return btrfs_ioctl_qgroup_limit(file, argp);
4956         case BTRFS_IOC_QUOTA_RESCAN:
4957                 return btrfs_ioctl_quota_rescan(file, argp);
4958         case BTRFS_IOC_QUOTA_RESCAN_STATUS:
4959                 return btrfs_ioctl_quota_rescan_status(file, argp);
4960         case BTRFS_IOC_QUOTA_RESCAN_WAIT:
4961                 return btrfs_ioctl_quota_rescan_wait(file, argp);
4962         case BTRFS_IOC_DEV_REPLACE:
4963                 return btrfs_ioctl_dev_replace(root, argp);
4964         case BTRFS_IOC_GET_FSLABEL:
4965                 return btrfs_ioctl_get_fslabel(file, argp);
4966         case BTRFS_IOC_SET_FSLABEL:
4967                 return btrfs_ioctl_set_fslabel(file, argp);
4968         case BTRFS_IOC_FILE_EXTENT_SAME:
4969                 return btrfs_ioctl_file_extent_same(file, argp);
4970         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
4971                 return btrfs_ioctl_get_supported_features(file, argp);
4972         case BTRFS_IOC_GET_FEATURES:
4973                 return btrfs_ioctl_get_features(file, argp);
4974         case BTRFS_IOC_SET_FEATURES:
4975                 return btrfs_ioctl_set_features(file, argp);
4976         }
4977 
4978         return -ENOTTY;
4979 }
4980 

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