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

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ 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-3.16.77 ] ~ [ 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-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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/compat.h>
 37 #include <linux/bit_spinlock.h>
 38 #include <linux/security.h>
 39 #include <linux/xattr.h>
 40 #include <linux/mm.h>
 41 #include <linux/slab.h>
 42 #include <linux/blkdev.h>
 43 #include <linux/uuid.h>
 44 #include <linux/btrfs.h>
 45 #include <linux/uaccess.h>
 46 #include "ctree.h"
 47 #include "disk-io.h"
 48 #include "transaction.h"
 49 #include "btrfs_inode.h"
 50 #include "print-tree.h"
 51 #include "volumes.h"
 52 #include "locking.h"
 53 #include "inode-map.h"
 54 #include "backref.h"
 55 #include "rcu-string.h"
 56 #include "send.h"
 57 #include "dev-replace.h"
 58 #include "props.h"
 59 #include "sysfs.h"
 60 #include "qgroup.h"
 61 #include "tree-log.h"
 62 #include "compression.h"
 63 
 64 #ifdef CONFIG_64BIT
 65 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
 66  * structures are incorrect, as the timespec structure from userspace
 67  * is 4 bytes too small. We define these alternatives here to teach
 68  * the kernel about the 32-bit struct packing.
 69  */
 70 struct btrfs_ioctl_timespec_32 {
 71         __u64 sec;
 72         __u32 nsec;
 73 } __attribute__ ((__packed__));
 74 
 75 struct btrfs_ioctl_received_subvol_args_32 {
 76         char    uuid[BTRFS_UUID_SIZE];  /* in */
 77         __u64   stransid;               /* in */
 78         __u64   rtransid;               /* out */
 79         struct btrfs_ioctl_timespec_32 stime; /* in */
 80         struct btrfs_ioctl_timespec_32 rtime; /* out */
 81         __u64   flags;                  /* in */
 82         __u64   reserved[16];           /* in */
 83 } __attribute__ ((__packed__));
 84 
 85 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
 86                                 struct btrfs_ioctl_received_subvol_args_32)
 87 #endif
 88 
 89 
 90 static int btrfs_clone(struct inode *src, struct inode *inode,
 91                        u64 off, u64 olen, u64 olen_aligned, u64 destoff,
 92                        int no_time_update);
 93 
 94 /* Mask out flags that are inappropriate for the given type of inode. */
 95 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
 96 {
 97         if (S_ISDIR(mode))
 98                 return flags;
 99         else if (S_ISREG(mode))
100                 return flags & ~FS_DIRSYNC_FL;
101         else
102                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
103 }
104 
105 /*
106  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
107  */
108 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
109 {
110         unsigned int iflags = 0;
111 
112         if (flags & BTRFS_INODE_SYNC)
113                 iflags |= FS_SYNC_FL;
114         if (flags & BTRFS_INODE_IMMUTABLE)
115                 iflags |= FS_IMMUTABLE_FL;
116         if (flags & BTRFS_INODE_APPEND)
117                 iflags |= FS_APPEND_FL;
118         if (flags & BTRFS_INODE_NODUMP)
119                 iflags |= FS_NODUMP_FL;
120         if (flags & BTRFS_INODE_NOATIME)
121                 iflags |= FS_NOATIME_FL;
122         if (flags & BTRFS_INODE_DIRSYNC)
123                 iflags |= FS_DIRSYNC_FL;
124         if (flags & BTRFS_INODE_NODATACOW)
125                 iflags |= FS_NOCOW_FL;
126 
127         if (flags & BTRFS_INODE_NOCOMPRESS)
128                 iflags |= FS_NOCOMP_FL;
129         else if (flags & BTRFS_INODE_COMPRESS)
130                 iflags |= FS_COMPR_FL;
131 
132         return iflags;
133 }
134 
135 /*
136  * Update inode->i_flags based on the btrfs internal flags.
137  */
138 void btrfs_update_iflags(struct inode *inode)
139 {
140         struct btrfs_inode *ip = BTRFS_I(inode);
141         unsigned int new_fl = 0;
142 
143         if (ip->flags & BTRFS_INODE_SYNC)
144                 new_fl |= S_SYNC;
145         if (ip->flags & BTRFS_INODE_IMMUTABLE)
146                 new_fl |= S_IMMUTABLE;
147         if (ip->flags & BTRFS_INODE_APPEND)
148                 new_fl |= S_APPEND;
149         if (ip->flags & BTRFS_INODE_NOATIME)
150                 new_fl |= S_NOATIME;
151         if (ip->flags & BTRFS_INODE_DIRSYNC)
152                 new_fl |= S_DIRSYNC;
153 
154         set_mask_bits(&inode->i_flags,
155                       S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
156                       new_fl);
157 }
158 
159 /*
160  * Inherit flags from the parent inode.
161  *
162  * Currently only the compression flags and the cow flags are inherited.
163  */
164 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
165 {
166         unsigned int flags;
167 
168         if (!dir)
169                 return;
170 
171         flags = BTRFS_I(dir)->flags;
172 
173         if (flags & BTRFS_INODE_NOCOMPRESS) {
174                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
175                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
176         } else if (flags & BTRFS_INODE_COMPRESS) {
177                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
178                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
179         }
180 
181         if (flags & BTRFS_INODE_NODATACOW) {
182                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
183                 if (S_ISREG(inode->i_mode))
184                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
185         }
186 
187         btrfs_update_iflags(inode);
188 }
189 
190 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
191 {
192         struct btrfs_inode *ip = BTRFS_I(file_inode(file));
193         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
194 
195         if (copy_to_user(arg, &flags, sizeof(flags)))
196                 return -EFAULT;
197         return 0;
198 }
199 
200 static int check_flags(unsigned int flags)
201 {
202         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
203                       FS_NOATIME_FL | FS_NODUMP_FL | \
204                       FS_SYNC_FL | FS_DIRSYNC_FL | \
205                       FS_NOCOMP_FL | FS_COMPR_FL |
206                       FS_NOCOW_FL))
207                 return -EOPNOTSUPP;
208 
209         if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
210                 return -EINVAL;
211 
212         return 0;
213 }
214 
215 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
216 {
217         struct inode *inode = file_inode(file);
218         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
219         struct btrfs_inode *ip = BTRFS_I(inode);
220         struct btrfs_root *root = ip->root;
221         struct btrfs_trans_handle *trans;
222         unsigned int flags, oldflags;
223         int ret;
224         u64 ip_oldflags;
225         unsigned int i_oldflags;
226         umode_t mode;
227 
228         if (!inode_owner_or_capable(inode))
229                 return -EPERM;
230 
231         if (btrfs_root_readonly(root))
232                 return -EROFS;
233 
234         if (copy_from_user(&flags, arg, sizeof(flags)))
235                 return -EFAULT;
236 
237         ret = check_flags(flags);
238         if (ret)
239                 return ret;
240 
241         ret = mnt_want_write_file(file);
242         if (ret)
243                 return ret;
244 
245         inode_lock(inode);
246 
247         ip_oldflags = ip->flags;
248         i_oldflags = inode->i_flags;
249         mode = inode->i_mode;
250 
251         flags = btrfs_mask_flags(inode->i_mode, flags);
252         oldflags = btrfs_flags_to_ioctl(ip->flags);
253         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
254                 if (!capable(CAP_LINUX_IMMUTABLE)) {
255                         ret = -EPERM;
256                         goto out_unlock;
257                 }
258         }
259 
260         if (flags & FS_SYNC_FL)
261                 ip->flags |= BTRFS_INODE_SYNC;
262         else
263                 ip->flags &= ~BTRFS_INODE_SYNC;
264         if (flags & FS_IMMUTABLE_FL)
265                 ip->flags |= BTRFS_INODE_IMMUTABLE;
266         else
267                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
268         if (flags & FS_APPEND_FL)
269                 ip->flags |= BTRFS_INODE_APPEND;
270         else
271                 ip->flags &= ~BTRFS_INODE_APPEND;
272         if (flags & FS_NODUMP_FL)
273                 ip->flags |= BTRFS_INODE_NODUMP;
274         else
275                 ip->flags &= ~BTRFS_INODE_NODUMP;
276         if (flags & FS_NOATIME_FL)
277                 ip->flags |= BTRFS_INODE_NOATIME;
278         else
279                 ip->flags &= ~BTRFS_INODE_NOATIME;
280         if (flags & FS_DIRSYNC_FL)
281                 ip->flags |= BTRFS_INODE_DIRSYNC;
282         else
283                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
284         if (flags & FS_NOCOW_FL) {
285                 if (S_ISREG(mode)) {
286                         /*
287                          * It's safe to turn csums off here, no extents exist.
288                          * Otherwise we want the flag to reflect the real COW
289                          * status of the file and will not set it.
290                          */
291                         if (inode->i_size == 0)
292                                 ip->flags |= BTRFS_INODE_NODATACOW
293                                            | BTRFS_INODE_NODATASUM;
294                 } else {
295                         ip->flags |= BTRFS_INODE_NODATACOW;
296                 }
297         } else {
298                 /*
299                  * Revert back under same assumptions as above
300                  */
301                 if (S_ISREG(mode)) {
302                         if (inode->i_size == 0)
303                                 ip->flags &= ~(BTRFS_INODE_NODATACOW
304                                              | BTRFS_INODE_NODATASUM);
305                 } else {
306                         ip->flags &= ~BTRFS_INODE_NODATACOW;
307                 }
308         }
309 
310         /*
311          * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
312          * flag may be changed automatically if compression code won't make
313          * things smaller.
314          */
315         if (flags & FS_NOCOMP_FL) {
316                 ip->flags &= ~BTRFS_INODE_COMPRESS;
317                 ip->flags |= BTRFS_INODE_NOCOMPRESS;
318 
319                 ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
320                 if (ret && ret != -ENODATA)
321                         goto out_drop;
322         } else if (flags & FS_COMPR_FL) {
323                 const char *comp;
324 
325                 ip->flags |= BTRFS_INODE_COMPRESS;
326                 ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
327 
328                 if (fs_info->compress_type == BTRFS_COMPRESS_LZO)
329                         comp = "lzo";
330                 else
331                         comp = "zlib";
332                 ret = btrfs_set_prop(inode, "btrfs.compression",
333                                      comp, strlen(comp), 0);
334                 if (ret)
335                         goto out_drop;
336 
337         } else {
338                 ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
339                 if (ret && ret != -ENODATA)
340                         goto out_drop;
341                 ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
342         }
343 
344         trans = btrfs_start_transaction(root, 1);
345         if (IS_ERR(trans)) {
346                 ret = PTR_ERR(trans);
347                 goto out_drop;
348         }
349 
350         btrfs_update_iflags(inode);
351         inode_inc_iversion(inode);
352         inode->i_ctime = current_time(inode);
353         ret = btrfs_update_inode(trans, root, inode);
354 
355         btrfs_end_transaction(trans);
356  out_drop:
357         if (ret) {
358                 ip->flags = ip_oldflags;
359                 inode->i_flags = i_oldflags;
360         }
361 
362  out_unlock:
363         inode_unlock(inode);
364         mnt_drop_write_file(file);
365         return ret;
366 }
367 
368 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
369 {
370         struct inode *inode = file_inode(file);
371 
372         return put_user(inode->i_generation, arg);
373 }
374 
375 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
376 {
377         struct inode *inode = file_inode(file);
378         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
379         struct btrfs_device *device;
380         struct request_queue *q;
381         struct fstrim_range range;
382         u64 minlen = ULLONG_MAX;
383         u64 num_devices = 0;
384         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
385         int ret;
386 
387         if (!capable(CAP_SYS_ADMIN))
388                 return -EPERM;
389 
390         rcu_read_lock();
391         list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
392                                 dev_list) {
393                 if (!device->bdev)
394                         continue;
395                 q = bdev_get_queue(device->bdev);
396                 if (blk_queue_discard(q)) {
397                         num_devices++;
398                         minlen = min_t(u64, q->limits.discard_granularity,
399                                      minlen);
400                 }
401         }
402         rcu_read_unlock();
403 
404         if (!num_devices)
405                 return -EOPNOTSUPP;
406         if (copy_from_user(&range, arg, sizeof(range)))
407                 return -EFAULT;
408         if (range.start > total_bytes ||
409             range.len < fs_info->sb->s_blocksize)
410                 return -EINVAL;
411 
412         range.len = min(range.len, total_bytes - range.start);
413         range.minlen = max(range.minlen, minlen);
414         ret = btrfs_trim_fs(fs_info, &range);
415         if (ret < 0)
416                 return ret;
417 
418         if (copy_to_user(arg, &range, sizeof(range)))
419                 return -EFAULT;
420 
421         return 0;
422 }
423 
424 int btrfs_is_empty_uuid(u8 *uuid)
425 {
426         int i;
427 
428         for (i = 0; i < BTRFS_UUID_SIZE; i++) {
429                 if (uuid[i])
430                         return 0;
431         }
432         return 1;
433 }
434 
435 static noinline int create_subvol(struct inode *dir,
436                                   struct dentry *dentry,
437                                   const char *name, int namelen,
438                                   u64 *async_transid,
439                                   struct btrfs_qgroup_inherit *inherit)
440 {
441         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
442         struct btrfs_trans_handle *trans;
443         struct btrfs_key key;
444         struct btrfs_root_item *root_item;
445         struct btrfs_inode_item *inode_item;
446         struct extent_buffer *leaf;
447         struct btrfs_root *root = BTRFS_I(dir)->root;
448         struct btrfs_root *new_root;
449         struct btrfs_block_rsv block_rsv;
450         struct timespec cur_time = current_time(dir);
451         struct inode *inode;
452         int ret;
453         int err;
454         u64 objectid;
455         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
456         u64 index = 0;
457         u64 qgroup_reserved;
458         uuid_le new_uuid;
459 
460         root_item = kzalloc(sizeof(*root_item), GFP_KERNEL);
461         if (!root_item)
462                 return -ENOMEM;
463 
464         ret = btrfs_find_free_objectid(fs_info->tree_root, &objectid);
465         if (ret)
466                 goto fail_free;
467 
468         /*
469          * Don't create subvolume whose level is not zero. Or qgroup will be
470          * screwed up since it assumes subvolume qgroup's level to be 0.
471          */
472         if (btrfs_qgroup_level(objectid)) {
473                 ret = -ENOSPC;
474                 goto fail_free;
475         }
476 
477         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
478         /*
479          * The same as the snapshot creation, please see the comment
480          * of create_snapshot().
481          */
482         ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
483                                                8, &qgroup_reserved, false);
484         if (ret)
485                 goto fail_free;
486 
487         trans = btrfs_start_transaction(root, 0);
488         if (IS_ERR(trans)) {
489                 ret = PTR_ERR(trans);
490                 btrfs_subvolume_release_metadata(fs_info, &block_rsv);
491                 goto fail_free;
492         }
493         trans->block_rsv = &block_rsv;
494         trans->bytes_reserved = block_rsv.size;
495 
496         ret = btrfs_qgroup_inherit(trans, fs_info, 0, objectid, inherit);
497         if (ret)
498                 goto fail;
499 
500         leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
501         if (IS_ERR(leaf)) {
502                 ret = PTR_ERR(leaf);
503                 goto fail;
504         }
505 
506         memzero_extent_buffer(leaf, 0, sizeof(struct btrfs_header));
507         btrfs_set_header_bytenr(leaf, leaf->start);
508         btrfs_set_header_generation(leaf, trans->transid);
509         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
510         btrfs_set_header_owner(leaf, objectid);
511 
512         write_extent_buffer_fsid(leaf, fs_info->fsid);
513         write_extent_buffer_chunk_tree_uuid(leaf, fs_info->chunk_tree_uuid);
514         btrfs_mark_buffer_dirty(leaf);
515 
516         inode_item = &root_item->inode;
517         btrfs_set_stack_inode_generation(inode_item, 1);
518         btrfs_set_stack_inode_size(inode_item, 3);
519         btrfs_set_stack_inode_nlink(inode_item, 1);
520         btrfs_set_stack_inode_nbytes(inode_item,
521                                      fs_info->nodesize);
522         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
523 
524         btrfs_set_root_flags(root_item, 0);
525         btrfs_set_root_limit(root_item, 0);
526         btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
527 
528         btrfs_set_root_bytenr(root_item, leaf->start);
529         btrfs_set_root_generation(root_item, trans->transid);
530         btrfs_set_root_level(root_item, 0);
531         btrfs_set_root_refs(root_item, 1);
532         btrfs_set_root_used(root_item, leaf->len);
533         btrfs_set_root_last_snapshot(root_item, 0);
534 
535         btrfs_set_root_generation_v2(root_item,
536                         btrfs_root_generation(root_item));
537         uuid_le_gen(&new_uuid);
538         memcpy(root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
539         btrfs_set_stack_timespec_sec(&root_item->otime, cur_time.tv_sec);
540         btrfs_set_stack_timespec_nsec(&root_item->otime, cur_time.tv_nsec);
541         root_item->ctime = root_item->otime;
542         btrfs_set_root_ctransid(root_item, trans->transid);
543         btrfs_set_root_otransid(root_item, trans->transid);
544 
545         btrfs_tree_unlock(leaf);
546         free_extent_buffer(leaf);
547         leaf = NULL;
548 
549         btrfs_set_root_dirid(root_item, new_dirid);
550 
551         key.objectid = objectid;
552         key.offset = 0;
553         key.type = BTRFS_ROOT_ITEM_KEY;
554         ret = btrfs_insert_root(trans, fs_info->tree_root, &key,
555                                 root_item);
556         if (ret)
557                 goto fail;
558 
559         key.offset = (u64)-1;
560         new_root = btrfs_read_fs_root_no_name(fs_info, &key);
561         if (IS_ERR(new_root)) {
562                 ret = PTR_ERR(new_root);
563                 btrfs_abort_transaction(trans, ret);
564                 goto fail;
565         }
566 
567         btrfs_record_root_in_trans(trans, new_root);
568 
569         ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
570         if (ret) {
571                 /* We potentially lose an unused inode item here */
572                 btrfs_abort_transaction(trans, ret);
573                 goto fail;
574         }
575 
576         mutex_lock(&new_root->objectid_mutex);
577         new_root->highest_objectid = new_dirid;
578         mutex_unlock(&new_root->objectid_mutex);
579 
580         /*
581          * insert the directory item
582          */
583         ret = btrfs_set_inode_index(BTRFS_I(dir), &index);
584         if (ret) {
585                 btrfs_abort_transaction(trans, ret);
586                 goto fail;
587         }
588 
589         ret = btrfs_insert_dir_item(trans, root,
590                                     name, namelen, BTRFS_I(dir), &key,
591                                     BTRFS_FT_DIR, index);
592         if (ret) {
593                 btrfs_abort_transaction(trans, ret);
594                 goto fail;
595         }
596 
597         btrfs_i_size_write(BTRFS_I(dir), dir->i_size + namelen * 2);
598         ret = btrfs_update_inode(trans, root, dir);
599         BUG_ON(ret);
600 
601         ret = btrfs_add_root_ref(trans, fs_info,
602                                  objectid, root->root_key.objectid,
603                                  btrfs_ino(BTRFS_I(dir)), index, name, namelen);
604         BUG_ON(ret);
605 
606         ret = btrfs_uuid_tree_add(trans, fs_info, root_item->uuid,
607                                   BTRFS_UUID_KEY_SUBVOL, objectid);
608         if (ret)
609                 btrfs_abort_transaction(trans, ret);
610 
611 fail:
612         kfree(root_item);
613         trans->block_rsv = NULL;
614         trans->bytes_reserved = 0;
615         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
616 
617         if (async_transid) {
618                 *async_transid = trans->transid;
619                 err = btrfs_commit_transaction_async(trans, 1);
620                 if (err)
621                         err = btrfs_commit_transaction(trans);
622         } else {
623                 err = btrfs_commit_transaction(trans);
624         }
625         if (err && !ret)
626                 ret = err;
627 
628         if (!ret) {
629                 inode = btrfs_lookup_dentry(dir, dentry);
630                 if (IS_ERR(inode))
631                         return PTR_ERR(inode);
632                 d_instantiate(dentry, inode);
633         }
634         return ret;
635 
636 fail_free:
637         kfree(root_item);
638         return ret;
639 }
640 
641 static void btrfs_wait_for_no_snapshoting_writes(struct btrfs_root *root)
642 {
643         s64 writers;
644         DEFINE_WAIT(wait);
645 
646         do {
647                 prepare_to_wait(&root->subv_writers->wait, &wait,
648                                 TASK_UNINTERRUPTIBLE);
649 
650                 writers = percpu_counter_sum(&root->subv_writers->counter);
651                 if (writers)
652                         schedule();
653 
654                 finish_wait(&root->subv_writers->wait, &wait);
655         } while (writers);
656 }
657 
658 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
659                            struct dentry *dentry,
660                            u64 *async_transid, bool readonly,
661                            struct btrfs_qgroup_inherit *inherit)
662 {
663         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
664         struct inode *inode;
665         struct btrfs_pending_snapshot *pending_snapshot;
666         struct btrfs_trans_handle *trans;
667         int ret;
668 
669         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
670                 return -EINVAL;
671 
672         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
673         if (!pending_snapshot)
674                 return -ENOMEM;
675 
676         pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item),
677                         GFP_KERNEL);
678         pending_snapshot->path = btrfs_alloc_path();
679         if (!pending_snapshot->root_item || !pending_snapshot->path) {
680                 ret = -ENOMEM;
681                 goto free_pending;
682         }
683 
684         atomic_inc(&root->will_be_snapshoted);
685         smp_mb__after_atomic();
686         btrfs_wait_for_no_snapshoting_writes(root);
687 
688         ret = btrfs_start_delalloc_inodes(root, 0);
689         if (ret)
690                 goto dec_and_free;
691 
692         btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
693 
694         btrfs_init_block_rsv(&pending_snapshot->block_rsv,
695                              BTRFS_BLOCK_RSV_TEMP);
696         /*
697          * 1 - parent dir inode
698          * 2 - dir entries
699          * 1 - root item
700          * 2 - root ref/backref
701          * 1 - root of snapshot
702          * 1 - UUID item
703          */
704         ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
705                                         &pending_snapshot->block_rsv, 8,
706                                         &pending_snapshot->qgroup_reserved,
707                                         false);
708         if (ret)
709                 goto dec_and_free;
710 
711         pending_snapshot->dentry = dentry;
712         pending_snapshot->root = root;
713         pending_snapshot->readonly = readonly;
714         pending_snapshot->dir = dir;
715         pending_snapshot->inherit = inherit;
716 
717         trans = btrfs_start_transaction(root, 0);
718         if (IS_ERR(trans)) {
719                 ret = PTR_ERR(trans);
720                 goto fail;
721         }
722 
723         spin_lock(&fs_info->trans_lock);
724         list_add(&pending_snapshot->list,
725                  &trans->transaction->pending_snapshots);
726         spin_unlock(&fs_info->trans_lock);
727         if (async_transid) {
728                 *async_transid = trans->transid;
729                 ret = btrfs_commit_transaction_async(trans, 1);
730                 if (ret)
731                         ret = btrfs_commit_transaction(trans);
732         } else {
733                 ret = btrfs_commit_transaction(trans);
734         }
735         if (ret)
736                 goto fail;
737 
738         ret = pending_snapshot->error;
739         if (ret)
740                 goto fail;
741 
742         ret = btrfs_orphan_cleanup(pending_snapshot->snap);
743         if (ret)
744                 goto fail;
745 
746         inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
747         if (IS_ERR(inode)) {
748                 ret = PTR_ERR(inode);
749                 goto fail;
750         }
751 
752         d_instantiate(dentry, inode);
753         ret = 0;
754 fail:
755         btrfs_subvolume_release_metadata(fs_info, &pending_snapshot->block_rsv);
756 dec_and_free:
757         if (atomic_dec_and_test(&root->will_be_snapshoted))
758                 wake_up_atomic_t(&root->will_be_snapshoted);
759 free_pending:
760         kfree(pending_snapshot->root_item);
761         btrfs_free_path(pending_snapshot->path);
762         kfree(pending_snapshot);
763 
764         return ret;
765 }
766 
767 /*  copy of may_delete in fs/namei.c()
768  *      Check whether we can remove a link victim from directory dir, check
769  *  whether the type of victim is right.
770  *  1. We can't do it if dir is read-only (done in permission())
771  *  2. We should have write and exec permissions on dir
772  *  3. We can't remove anything from append-only dir
773  *  4. We can't do anything with immutable dir (done in permission())
774  *  5. If the sticky bit on dir is set we should either
775  *      a. be owner of dir, or
776  *      b. be owner of victim, or
777  *      c. have CAP_FOWNER capability
778  *  6. If the victim is append-only or immutable we can't do anything with
779  *     links pointing to it.
780  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
781  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
782  *  9. We can't remove a root or mountpoint.
783  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
784  *     nfs_async_unlink().
785  */
786 
787 static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
788 {
789         int error;
790 
791         if (d_really_is_negative(victim))
792                 return -ENOENT;
793 
794         BUG_ON(d_inode(victim->d_parent) != dir);
795         audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
796 
797         error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
798         if (error)
799                 return error;
800         if (IS_APPEND(dir))
801                 return -EPERM;
802         if (check_sticky(dir, d_inode(victim)) || IS_APPEND(d_inode(victim)) ||
803             IS_IMMUTABLE(d_inode(victim)) || IS_SWAPFILE(d_inode(victim)))
804                 return -EPERM;
805         if (isdir) {
806                 if (!d_is_dir(victim))
807                         return -ENOTDIR;
808                 if (IS_ROOT(victim))
809                         return -EBUSY;
810         } else if (d_is_dir(victim))
811                 return -EISDIR;
812         if (IS_DEADDIR(dir))
813                 return -ENOENT;
814         if (victim->d_flags & DCACHE_NFSFS_RENAMED)
815                 return -EBUSY;
816         return 0;
817 }
818 
819 /* copy of may_create in fs/namei.c() */
820 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
821 {
822         if (d_really_is_positive(child))
823                 return -EEXIST;
824         if (IS_DEADDIR(dir))
825                 return -ENOENT;
826         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
827 }
828 
829 /*
830  * Create a new subvolume below @parent.  This is largely modeled after
831  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
832  * inside this filesystem so it's quite a bit simpler.
833  */
834 static noinline int btrfs_mksubvol(const struct path *parent,
835                                    const char *name, int namelen,
836                                    struct btrfs_root *snap_src,
837                                    u64 *async_transid, bool readonly,
838                                    struct btrfs_qgroup_inherit *inherit)
839 {
840         struct inode *dir = d_inode(parent->dentry);
841         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
842         struct dentry *dentry;
843         int error;
844 
845         error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
846         if (error == -EINTR)
847                 return error;
848 
849         dentry = lookup_one_len(name, parent->dentry, namelen);
850         error = PTR_ERR(dentry);
851         if (IS_ERR(dentry))
852                 goto out_unlock;
853 
854         error = btrfs_may_create(dir, dentry);
855         if (error)
856                 goto out_dput;
857 
858         /*
859          * even if this name doesn't exist, we may get hash collisions.
860          * check for them now when we can safely fail
861          */
862         error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
863                                                dir->i_ino, name,
864                                                namelen);
865         if (error)
866                 goto out_dput;
867 
868         down_read(&fs_info->subvol_sem);
869 
870         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
871                 goto out_up_read;
872 
873         if (snap_src) {
874                 error = create_snapshot(snap_src, dir, dentry,
875                                         async_transid, readonly, inherit);
876         } else {
877                 error = create_subvol(dir, dentry, name, namelen,
878                                       async_transid, inherit);
879         }
880         if (!error)
881                 fsnotify_mkdir(dir, dentry);
882 out_up_read:
883         up_read(&fs_info->subvol_sem);
884 out_dput:
885         dput(dentry);
886 out_unlock:
887         inode_unlock(dir);
888         return error;
889 }
890 
891 /*
892  * When we're defragging a range, we don't want to kick it off again
893  * if it is really just waiting for delalloc to send it down.
894  * If we find a nice big extent or delalloc range for the bytes in the
895  * file you want to defrag, we return 0 to let you know to skip this
896  * part of the file
897  */
898 static int check_defrag_in_cache(struct inode *inode, u64 offset, u32 thresh)
899 {
900         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
901         struct extent_map *em = NULL;
902         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
903         u64 end;
904 
905         read_lock(&em_tree->lock);
906         em = lookup_extent_mapping(em_tree, offset, PAGE_SIZE);
907         read_unlock(&em_tree->lock);
908 
909         if (em) {
910                 end = extent_map_end(em);
911                 free_extent_map(em);
912                 if (end - offset > thresh)
913                         return 0;
914         }
915         /* if we already have a nice delalloc here, just stop */
916         thresh /= 2;
917         end = count_range_bits(io_tree, &offset, offset + thresh,
918                                thresh, EXTENT_DELALLOC, 1);
919         if (end >= thresh)
920                 return 0;
921         return 1;
922 }
923 
924 /*
925  * helper function to walk through a file and find extents
926  * newer than a specific transid, and smaller than thresh.
927  *
928  * This is used by the defragging code to find new and small
929  * extents
930  */
931 static int find_new_extents(struct btrfs_root *root,
932                             struct inode *inode, u64 newer_than,
933                             u64 *off, u32 thresh)
934 {
935         struct btrfs_path *path;
936         struct btrfs_key min_key;
937         struct extent_buffer *leaf;
938         struct btrfs_file_extent_item *extent;
939         int type;
940         int ret;
941         u64 ino = btrfs_ino(BTRFS_I(inode));
942 
943         path = btrfs_alloc_path();
944         if (!path)
945                 return -ENOMEM;
946 
947         min_key.objectid = ino;
948         min_key.type = BTRFS_EXTENT_DATA_KEY;
949         min_key.offset = *off;
950 
951         while (1) {
952                 ret = btrfs_search_forward(root, &min_key, path, newer_than);
953                 if (ret != 0)
954                         goto none;
955 process_slot:
956                 if (min_key.objectid != ino)
957                         goto none;
958                 if (min_key.type != BTRFS_EXTENT_DATA_KEY)
959                         goto none;
960 
961                 leaf = path->nodes[0];
962                 extent = btrfs_item_ptr(leaf, path->slots[0],
963                                         struct btrfs_file_extent_item);
964 
965                 type = btrfs_file_extent_type(leaf, extent);
966                 if (type == BTRFS_FILE_EXTENT_REG &&
967                     btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
968                     check_defrag_in_cache(inode, min_key.offset, thresh)) {
969                         *off = min_key.offset;
970                         btrfs_free_path(path);
971                         return 0;
972                 }
973 
974                 path->slots[0]++;
975                 if (path->slots[0] < btrfs_header_nritems(leaf)) {
976                         btrfs_item_key_to_cpu(leaf, &min_key, path->slots[0]);
977                         goto process_slot;
978                 }
979 
980                 if (min_key.offset == (u64)-1)
981                         goto none;
982 
983                 min_key.offset++;
984                 btrfs_release_path(path);
985         }
986 none:
987         btrfs_free_path(path);
988         return -ENOENT;
989 }
990 
991 static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start)
992 {
993         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
994         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
995         struct extent_map *em;
996         u64 len = PAGE_SIZE;
997 
998         /*
999          * hopefully we have this extent in the tree already, try without
1000          * the full extent lock
1001          */
1002         read_lock(&em_tree->lock);
1003         em = lookup_extent_mapping(em_tree, start, len);
1004         read_unlock(&em_tree->lock);
1005 
1006         if (!em) {
1007                 struct extent_state *cached = NULL;
1008                 u64 end = start + len - 1;
1009 
1010                 /* get the big lock and read metadata off disk */
1011                 lock_extent_bits(io_tree, start, end, &cached);
1012                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
1013                 unlock_extent_cached(io_tree, start, end, &cached, GFP_NOFS);
1014 
1015                 if (IS_ERR(em))
1016                         return NULL;
1017         }
1018 
1019         return em;
1020 }
1021 
1022 static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
1023 {
1024         struct extent_map *next;
1025         bool ret = true;
1026 
1027         /* this is the last extent */
1028         if (em->start + em->len >= i_size_read(inode))
1029                 return false;
1030 
1031         next = defrag_lookup_extent(inode, em->start + em->len);
1032         if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
1033                 ret = false;
1034         else if ((em->block_start + em->block_len == next->block_start) &&
1035                  (em->block_len > SZ_128K && next->block_len > SZ_128K))
1036                 ret = false;
1037 
1038         free_extent_map(next);
1039         return ret;
1040 }
1041 
1042 static int should_defrag_range(struct inode *inode, u64 start, u32 thresh,
1043                                u64 *last_len, u64 *skip, u64 *defrag_end,
1044                                int compress)
1045 {
1046         struct extent_map *em;
1047         int ret = 1;
1048         bool next_mergeable = true;
1049         bool prev_mergeable = true;
1050 
1051         /*
1052          * make sure that once we start defragging an extent, we keep on
1053          * defragging it
1054          */
1055         if (start < *defrag_end)
1056                 return 1;
1057 
1058         *skip = 0;
1059 
1060         em = defrag_lookup_extent(inode, start);
1061         if (!em)
1062                 return 0;
1063 
1064         /* this will cover holes, and inline extents */
1065         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1066                 ret = 0;
1067                 goto out;
1068         }
1069 
1070         if (!*defrag_end)
1071                 prev_mergeable = false;
1072 
1073         next_mergeable = defrag_check_next_extent(inode, em);
1074         /*
1075          * we hit a real extent, if it is big or the next extent is not a
1076          * real extent, don't bother defragging it
1077          */
1078         if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1079             (em->len >= thresh || (!next_mergeable && !prev_mergeable)))
1080                 ret = 0;
1081 out:
1082         /*
1083          * last_len ends up being a counter of how many bytes we've defragged.
1084          * every time we choose not to defrag an extent, we reset *last_len
1085          * so that the next tiny extent will force a defrag.
1086          *
1087          * The end result of this is that tiny extents before a single big
1088          * extent will force at least part of that big extent to be defragged.
1089          */
1090         if (ret) {
1091                 *defrag_end = extent_map_end(em);
1092         } else {
1093                 *last_len = 0;
1094                 *skip = extent_map_end(em);
1095                 *defrag_end = 0;
1096         }
1097 
1098         free_extent_map(em);
1099         return ret;
1100 }
1101 
1102 /*
1103  * it doesn't do much good to defrag one or two pages
1104  * at a time.  This pulls in a nice chunk of pages
1105  * to COW and defrag.
1106  *
1107  * It also makes sure the delalloc code has enough
1108  * dirty data to avoid making new small extents as part
1109  * of the defrag
1110  *
1111  * It's a good idea to start RA on this range
1112  * before calling this.
1113  */
1114 static int cluster_pages_for_defrag(struct inode *inode,
1115                                     struct page **pages,
1116                                     unsigned long start_index,
1117                                     unsigned long num_pages)
1118 {
1119         unsigned long file_end;
1120         u64 isize = i_size_read(inode);
1121         u64 page_start;
1122         u64 page_end;
1123         u64 page_cnt;
1124         int ret;
1125         int i;
1126         int i_done;
1127         struct btrfs_ordered_extent *ordered;
1128         struct extent_state *cached_state = NULL;
1129         struct extent_io_tree *tree;
1130         struct extent_changeset *data_reserved = NULL;
1131         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1132 
1133         file_end = (isize - 1) >> PAGE_SHIFT;
1134         if (!isize || start_index > file_end)
1135                 return 0;
1136 
1137         page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1138 
1139         ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
1140                         start_index << PAGE_SHIFT,
1141                         page_cnt << PAGE_SHIFT);
1142         if (ret)
1143                 return ret;
1144         i_done = 0;
1145         tree = &BTRFS_I(inode)->io_tree;
1146 
1147         /* step one, lock all the pages */
1148         for (i = 0; i < page_cnt; i++) {
1149                 struct page *page;
1150 again:
1151                 page = find_or_create_page(inode->i_mapping,
1152                                            start_index + i, mask);
1153                 if (!page)
1154                         break;
1155 
1156                 page_start = page_offset(page);
1157                 page_end = page_start + PAGE_SIZE - 1;
1158                 while (1) {
1159                         lock_extent_bits(tree, page_start, page_end,
1160                                          &cached_state);
1161                         ordered = btrfs_lookup_ordered_extent(inode,
1162                                                               page_start);
1163                         unlock_extent_cached(tree, page_start, page_end,
1164                                              &cached_state, GFP_NOFS);
1165                         if (!ordered)
1166                                 break;
1167 
1168                         unlock_page(page);
1169                         btrfs_start_ordered_extent(inode, ordered, 1);
1170                         btrfs_put_ordered_extent(ordered);
1171                         lock_page(page);
1172                         /*
1173                          * we unlocked the page above, so we need check if
1174                          * it was released or not.
1175                          */
1176                         if (page->mapping != inode->i_mapping) {
1177                                 unlock_page(page);
1178                                 put_page(page);
1179                                 goto again;
1180                         }
1181                 }
1182 
1183                 if (!PageUptodate(page)) {
1184                         btrfs_readpage(NULL, page);
1185                         lock_page(page);
1186                         if (!PageUptodate(page)) {
1187                                 unlock_page(page);
1188                                 put_page(page);
1189                                 ret = -EIO;
1190                                 break;
1191                         }
1192                 }
1193 
1194                 if (page->mapping != inode->i_mapping) {
1195                         unlock_page(page);
1196                         put_page(page);
1197                         goto again;
1198                 }
1199 
1200                 pages[i] = page;
1201                 i_done++;
1202         }
1203         if (!i_done || ret)
1204                 goto out;
1205 
1206         if (!(inode->i_sb->s_flags & MS_ACTIVE))
1207                 goto out;
1208 
1209         /*
1210          * so now we have a nice long stream of locked
1211          * and up to date pages, lets wait on them
1212          */
1213         for (i = 0; i < i_done; i++)
1214                 wait_on_page_writeback(pages[i]);
1215 
1216         page_start = page_offset(pages[0]);
1217         page_end = page_offset(pages[i_done - 1]) + PAGE_SIZE;
1218 
1219         lock_extent_bits(&BTRFS_I(inode)->io_tree,
1220                          page_start, page_end - 1, &cached_state);
1221         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1222                           page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1223                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1224                           &cached_state, GFP_NOFS);
1225 
1226         if (i_done != page_cnt) {
1227                 spin_lock(&BTRFS_I(inode)->lock);
1228                 BTRFS_I(inode)->outstanding_extents++;
1229                 spin_unlock(&BTRFS_I(inode)->lock);
1230                 btrfs_delalloc_release_space(inode, data_reserved,
1231                                 start_index << PAGE_SHIFT,
1232                                 (page_cnt - i_done) << PAGE_SHIFT);
1233         }
1234 
1235 
1236         set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1237                           &cached_state);
1238 
1239         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1240                              page_start, page_end - 1, &cached_state,
1241                              GFP_NOFS);
1242 
1243         for (i = 0; i < i_done; i++) {
1244                 clear_page_dirty_for_io(pages[i]);
1245                 ClearPageChecked(pages[i]);
1246                 set_page_extent_mapped(pages[i]);
1247                 set_page_dirty(pages[i]);
1248                 unlock_page(pages[i]);
1249                 put_page(pages[i]);
1250         }
1251         extent_changeset_free(data_reserved);
1252         return i_done;
1253 out:
1254         for (i = 0; i < i_done; i++) {
1255                 unlock_page(pages[i]);
1256                 put_page(pages[i]);
1257         }
1258         btrfs_delalloc_release_space(inode, data_reserved,
1259                         start_index << PAGE_SHIFT,
1260                         page_cnt << PAGE_SHIFT);
1261         extent_changeset_free(data_reserved);
1262         return ret;
1263 
1264 }
1265 
1266 int btrfs_defrag_file(struct inode *inode, struct file *file,
1267                       struct btrfs_ioctl_defrag_range_args *range,
1268                       u64 newer_than, unsigned long max_to_defrag)
1269 {
1270         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1271         struct btrfs_root *root = BTRFS_I(inode)->root;
1272         struct file_ra_state *ra = NULL;
1273         unsigned long last_index;
1274         u64 isize = i_size_read(inode);
1275         u64 last_len = 0;
1276         u64 skip = 0;
1277         u64 defrag_end = 0;
1278         u64 newer_off = range->start;
1279         unsigned long i;
1280         unsigned long ra_index = 0;
1281         int ret;
1282         int defrag_count = 0;
1283         int compress_type = BTRFS_COMPRESS_ZLIB;
1284         u32 extent_thresh = range->extent_thresh;
1285         unsigned long max_cluster = SZ_256K >> PAGE_SHIFT;
1286         unsigned long cluster = max_cluster;
1287         u64 new_align = ~((u64)SZ_128K - 1);
1288         struct page **pages = NULL;
1289 
1290         if (isize == 0)
1291                 return 0;
1292 
1293         if (range->start >= isize)
1294                 return -EINVAL;
1295 
1296         if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1297                 if (range->compress_type > BTRFS_COMPRESS_TYPES)
1298                         return -EINVAL;
1299                 if (range->compress_type)
1300                         compress_type = range->compress_type;
1301         }
1302 
1303         if (extent_thresh == 0)
1304                 extent_thresh = SZ_256K;
1305 
1306         /*
1307          * if we were not given a file, allocate a readahead
1308          * context
1309          */
1310         if (!file) {
1311                 ra = kzalloc(sizeof(*ra), GFP_NOFS);
1312                 if (!ra)
1313                         return -ENOMEM;
1314                 file_ra_state_init(ra, inode->i_mapping);
1315         } else {
1316                 ra = &file->f_ra;
1317         }
1318 
1319         pages = kmalloc_array(max_cluster, sizeof(struct page *),
1320                         GFP_NOFS);
1321         if (!pages) {
1322                 ret = -ENOMEM;
1323                 goto out_ra;
1324         }
1325 
1326         /* find the last page to defrag */
1327         if (range->start + range->len > range->start) {
1328                 last_index = min_t(u64, isize - 1,
1329                          range->start + range->len - 1) >> PAGE_SHIFT;
1330         } else {
1331                 last_index = (isize - 1) >> PAGE_SHIFT;
1332         }
1333 
1334         if (newer_than) {
1335                 ret = find_new_extents(root, inode, newer_than,
1336                                        &newer_off, SZ_64K);
1337                 if (!ret) {
1338                         range->start = newer_off;
1339                         /*
1340                          * we always align our defrag to help keep
1341                          * the extents in the file evenly spaced
1342                          */
1343                         i = (newer_off & new_align) >> PAGE_SHIFT;
1344                 } else
1345                         goto out_ra;
1346         } else {
1347                 i = range->start >> PAGE_SHIFT;
1348         }
1349         if (!max_to_defrag)
1350                 max_to_defrag = last_index - i + 1;
1351 
1352         /*
1353          * make writeback starts from i, so the defrag range can be
1354          * written sequentially.
1355          */
1356         if (i < inode->i_mapping->writeback_index)
1357                 inode->i_mapping->writeback_index = i;
1358 
1359         while (i <= last_index && defrag_count < max_to_defrag &&
1360                (i < DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE))) {
1361                 /*
1362                  * make sure we stop running if someone unmounts
1363                  * the FS
1364                  */
1365                 if (!(inode->i_sb->s_flags & MS_ACTIVE))
1366                         break;
1367 
1368                 if (btrfs_defrag_cancelled(fs_info)) {
1369                         btrfs_debug(fs_info, "defrag_file cancelled");
1370                         ret = -EAGAIN;
1371                         break;
1372                 }
1373 
1374                 if (!should_defrag_range(inode, (u64)i << PAGE_SHIFT,
1375                                          extent_thresh, &last_len, &skip,
1376                                          &defrag_end, range->flags &
1377                                          BTRFS_DEFRAG_RANGE_COMPRESS)) {
1378                         unsigned long next;
1379                         /*
1380                          * the should_defrag function tells us how much to skip
1381                          * bump our counter by the suggested amount
1382                          */
1383                         next = DIV_ROUND_UP(skip, PAGE_SIZE);
1384                         i = max(i + 1, next);
1385                         continue;
1386                 }
1387 
1388                 if (!newer_than) {
1389                         cluster = (PAGE_ALIGN(defrag_end) >>
1390                                    PAGE_SHIFT) - i;
1391                         cluster = min(cluster, max_cluster);
1392                 } else {
1393                         cluster = max_cluster;
1394                 }
1395 
1396                 if (i + cluster > ra_index) {
1397                         ra_index = max(i, ra_index);
1398                         btrfs_force_ra(inode->i_mapping, ra, file, ra_index,
1399                                        cluster);
1400                         ra_index += cluster;
1401                 }
1402 
1403                 inode_lock(inode);
1404                 if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
1405                         BTRFS_I(inode)->force_compress = compress_type;
1406                 ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1407                 if (ret < 0) {
1408                         inode_unlock(inode);
1409                         goto out_ra;
1410                 }
1411 
1412                 defrag_count += ret;
1413                 balance_dirty_pages_ratelimited(inode->i_mapping);
1414                 inode_unlock(inode);
1415 
1416                 if (newer_than) {
1417                         if (newer_off == (u64)-1)
1418                                 break;
1419 
1420                         if (ret > 0)
1421                                 i += ret;
1422 
1423                         newer_off = max(newer_off + 1,
1424                                         (u64)i << PAGE_SHIFT);
1425 
1426                         ret = find_new_extents(root, inode, newer_than,
1427                                                &newer_off, SZ_64K);
1428                         if (!ret) {
1429                                 range->start = newer_off;
1430                                 i = (newer_off & new_align) >> PAGE_SHIFT;
1431                         } else {
1432                                 break;
1433                         }
1434                 } else {
1435                         if (ret > 0) {
1436                                 i += ret;
1437                                 last_len += ret << PAGE_SHIFT;
1438                         } else {
1439                                 i++;
1440                                 last_len = 0;
1441                         }
1442                 }
1443         }
1444 
1445         if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1446                 filemap_flush(inode->i_mapping);
1447                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1448                              &BTRFS_I(inode)->runtime_flags))
1449                         filemap_flush(inode->i_mapping);
1450         }
1451 
1452         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1453                 /* the filemap_flush will queue IO into the worker threads, but
1454                  * we have to make sure the IO is actually started and that
1455                  * ordered extents get created before we return
1456                  */
1457                 atomic_inc(&fs_info->async_submit_draining);
1458                 while (atomic_read(&fs_info->nr_async_submits) ||
1459                        atomic_read(&fs_info->async_delalloc_pages)) {
1460                         wait_event(fs_info->async_submit_wait,
1461                                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
1462                                     atomic_read(&fs_info->async_delalloc_pages) == 0));
1463                 }
1464                 atomic_dec(&fs_info->async_submit_draining);
1465         }
1466 
1467         if (range->compress_type == BTRFS_COMPRESS_LZO) {
1468                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
1469         }
1470 
1471         ret = defrag_count;
1472 
1473 out_ra:
1474         if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
1475                 inode_lock(inode);
1476                 BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
1477                 inode_unlock(inode);
1478         }
1479         if (!file)
1480                 kfree(ra);
1481         kfree(pages);
1482         return ret;
1483 }
1484 
1485 static noinline int btrfs_ioctl_resize(struct file *file,
1486                                         void __user *arg)
1487 {
1488         struct inode *inode = file_inode(file);
1489         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1490         u64 new_size;
1491         u64 old_size;
1492         u64 devid = 1;
1493         struct btrfs_root *root = BTRFS_I(inode)->root;
1494         struct btrfs_ioctl_vol_args *vol_args;
1495         struct btrfs_trans_handle *trans;
1496         struct btrfs_device *device = NULL;
1497         char *sizestr;
1498         char *retptr;
1499         char *devstr = NULL;
1500         int ret = 0;
1501         int mod = 0;
1502 
1503         if (!capable(CAP_SYS_ADMIN))
1504                 return -EPERM;
1505 
1506         ret = mnt_want_write_file(file);
1507         if (ret)
1508                 return ret;
1509 
1510         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
1511                 mnt_drop_write_file(file);
1512                 return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1513         }
1514 
1515         mutex_lock(&fs_info->volume_mutex);
1516         vol_args = memdup_user(arg, sizeof(*vol_args));
1517         if (IS_ERR(vol_args)) {
1518                 ret = PTR_ERR(vol_args);
1519                 goto out;
1520         }
1521 
1522         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1523 
1524         sizestr = vol_args->name;
1525         devstr = strchr(sizestr, ':');
1526         if (devstr) {
1527                 sizestr = devstr + 1;
1528                 *devstr = '\0';
1529                 devstr = vol_args->name;
1530                 ret = kstrtoull(devstr, 10, &devid);
1531                 if (ret)
1532                         goto out_free;
1533                 if (!devid) {
1534                         ret = -EINVAL;
1535                         goto out_free;
1536                 }
1537                 btrfs_info(fs_info, "resizing devid %llu", devid);
1538         }
1539 
1540         device = btrfs_find_device(fs_info, devid, NULL, NULL);
1541         if (!device) {
1542                 btrfs_info(fs_info, "resizer unable to find device %llu",
1543                            devid);
1544                 ret = -ENODEV;
1545                 goto out_free;
1546         }
1547 
1548         if (!device->writeable) {
1549                 btrfs_info(fs_info,
1550                            "resizer unable to apply on readonly device %llu",
1551                        devid);
1552                 ret = -EPERM;
1553                 goto out_free;
1554         }
1555 
1556         if (!strcmp(sizestr, "max"))
1557                 new_size = device->bdev->bd_inode->i_size;
1558         else {
1559                 if (sizestr[0] == '-') {
1560                         mod = -1;
1561                         sizestr++;
1562                 } else if (sizestr[0] == '+') {
1563                         mod = 1;
1564                         sizestr++;
1565                 }
1566                 new_size = memparse(sizestr, &retptr);
1567                 if (*retptr != '\0' || new_size == 0) {
1568                         ret = -EINVAL;
1569                         goto out_free;
1570                 }
1571         }
1572 
1573         if (device->is_tgtdev_for_dev_replace) {
1574                 ret = -EPERM;
1575                 goto out_free;
1576         }
1577 
1578         old_size = btrfs_device_get_total_bytes(device);
1579 
1580         if (mod < 0) {
1581                 if (new_size > old_size) {
1582                         ret = -EINVAL;
1583                         goto out_free;
1584                 }
1585                 new_size = old_size - new_size;
1586         } else if (mod > 0) {
1587                 if (new_size > ULLONG_MAX - old_size) {
1588                         ret = -ERANGE;
1589                         goto out_free;
1590                 }
1591                 new_size = old_size + new_size;
1592         }
1593 
1594         if (new_size < SZ_256M) {
1595                 ret = -EINVAL;
1596                 goto out_free;
1597         }
1598         if (new_size > device->bdev->bd_inode->i_size) {
1599                 ret = -EFBIG;
1600                 goto out_free;
1601         }
1602 
1603         new_size = div_u64(new_size, fs_info->sectorsize);
1604         new_size *= fs_info->sectorsize;
1605 
1606         btrfs_info_in_rcu(fs_info, "new size for %s is %llu",
1607                           rcu_str_deref(device->name), new_size);
1608 
1609         if (new_size > old_size) {
1610                 trans = btrfs_start_transaction(root, 0);
1611                 if (IS_ERR(trans)) {
1612                         ret = PTR_ERR(trans);
1613                         goto out_free;
1614                 }
1615                 ret = btrfs_grow_device(trans, device, new_size);
1616                 btrfs_commit_transaction(trans);
1617         } else if (new_size < old_size) {
1618                 ret = btrfs_shrink_device(device, new_size);
1619         } /* equal, nothing need to do */
1620 
1621 out_free:
1622         kfree(vol_args);
1623 out:
1624         mutex_unlock(&fs_info->volume_mutex);
1625         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
1626         mnt_drop_write_file(file);
1627         return ret;
1628 }
1629 
1630 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1631                                 const char *name, unsigned long fd, int subvol,
1632                                 u64 *transid, bool readonly,
1633                                 struct btrfs_qgroup_inherit *inherit)
1634 {
1635         int namelen;
1636         int ret = 0;
1637 
1638         if (!S_ISDIR(file_inode(file)->i_mode))
1639                 return -ENOTDIR;
1640 
1641         ret = mnt_want_write_file(file);
1642         if (ret)
1643                 goto out;
1644 
1645         namelen = strlen(name);
1646         if (strchr(name, '/')) {
1647                 ret = -EINVAL;
1648                 goto out_drop_write;
1649         }
1650 
1651         if (name[0] == '.' &&
1652            (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1653                 ret = -EEXIST;
1654                 goto out_drop_write;
1655         }
1656 
1657         if (subvol) {
1658                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
1659                                      NULL, transid, readonly, inherit);
1660         } else {
1661                 struct fd src = fdget(fd);
1662                 struct inode *src_inode;
1663                 if (!src.file) {
1664                         ret = -EINVAL;
1665                         goto out_drop_write;
1666                 }
1667 
1668                 src_inode = file_inode(src.file);
1669                 if (src_inode->i_sb != file_inode(file)->i_sb) {
1670                         btrfs_info(BTRFS_I(file_inode(file))->root->fs_info,
1671                                    "Snapshot src from another FS");
1672                         ret = -EXDEV;
1673                 } else if (!inode_owner_or_capable(src_inode)) {
1674                         /*
1675                          * Subvolume creation is not restricted, but snapshots
1676                          * are limited to own subvolumes only
1677                          */
1678                         ret = -EPERM;
1679                 } else {
1680                         ret = btrfs_mksubvol(&file->f_path, name, namelen,
1681                                              BTRFS_I(src_inode)->root,
1682                                              transid, readonly, inherit);
1683                 }
1684                 fdput(src);
1685         }
1686 out_drop_write:
1687         mnt_drop_write_file(file);
1688 out:
1689         return ret;
1690 }
1691 
1692 static noinline int btrfs_ioctl_snap_create(struct file *file,
1693                                             void __user *arg, int subvol)
1694 {
1695         struct btrfs_ioctl_vol_args *vol_args;
1696         int ret;
1697 
1698         if (!S_ISDIR(file_inode(file)->i_mode))
1699                 return -ENOTDIR;
1700 
1701         vol_args = memdup_user(arg, sizeof(*vol_args));
1702         if (IS_ERR(vol_args))
1703                 return PTR_ERR(vol_args);
1704         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1705 
1706         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1707                                               vol_args->fd, subvol,
1708                                               NULL, false, NULL);
1709 
1710         kfree(vol_args);
1711         return ret;
1712 }
1713 
1714 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1715                                                void __user *arg, int subvol)
1716 {
1717         struct btrfs_ioctl_vol_args_v2 *vol_args;
1718         int ret;
1719         u64 transid = 0;
1720         u64 *ptr = NULL;
1721         bool readonly = false;
1722         struct btrfs_qgroup_inherit *inherit = NULL;
1723 
1724         if (!S_ISDIR(file_inode(file)->i_mode))
1725                 return -ENOTDIR;
1726 
1727         vol_args = memdup_user(arg, sizeof(*vol_args));
1728         if (IS_ERR(vol_args))
1729                 return PTR_ERR(vol_args);
1730         vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1731 
1732         if (vol_args->flags &
1733             ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
1734               BTRFS_SUBVOL_QGROUP_INHERIT)) {
1735                 ret = -EOPNOTSUPP;
1736                 goto free_args;
1737         }
1738 
1739         if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
1740                 ptr = &transid;
1741         if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1742                 readonly = true;
1743         if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1744                 if (vol_args->size > PAGE_SIZE) {
1745                         ret = -EINVAL;
1746                         goto free_args;
1747                 }
1748                 inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1749                 if (IS_ERR(inherit)) {
1750                         ret = PTR_ERR(inherit);
1751                         goto free_args;
1752                 }
1753         }
1754 
1755         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1756                                               vol_args->fd, subvol, ptr,
1757                                               readonly, inherit);
1758         if (ret)
1759                 goto free_inherit;
1760 
1761         if (ptr && copy_to_user(arg +
1762                                 offsetof(struct btrfs_ioctl_vol_args_v2,
1763                                         transid),
1764                                 ptr, sizeof(*ptr)))
1765                 ret = -EFAULT;
1766 
1767 free_inherit:
1768         kfree(inherit);
1769 free_args:
1770         kfree(vol_args);
1771         return ret;
1772 }
1773 
1774 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1775                                                 void __user *arg)
1776 {
1777         struct inode *inode = file_inode(file);
1778         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1779         struct btrfs_root *root = BTRFS_I(inode)->root;
1780         int ret = 0;
1781         u64 flags = 0;
1782 
1783         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID)
1784                 return -EINVAL;
1785 
1786         down_read(&fs_info->subvol_sem);
1787         if (btrfs_root_readonly(root))
1788                 flags |= BTRFS_SUBVOL_RDONLY;
1789         up_read(&fs_info->subvol_sem);
1790 
1791         if (copy_to_user(arg, &flags, sizeof(flags)))
1792                 ret = -EFAULT;
1793 
1794         return ret;
1795 }
1796 
1797 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1798                                               void __user *arg)
1799 {
1800         struct inode *inode = file_inode(file);
1801         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1802         struct btrfs_root *root = BTRFS_I(inode)->root;
1803         struct btrfs_trans_handle *trans;
1804         u64 root_flags;
1805         u64 flags;
1806         int ret = 0;
1807 
1808         if (!inode_owner_or_capable(inode))
1809                 return -EPERM;
1810 
1811         ret = mnt_want_write_file(file);
1812         if (ret)
1813                 goto out;
1814 
1815         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1816                 ret = -EINVAL;
1817                 goto out_drop_write;
1818         }
1819 
1820         if (copy_from_user(&flags, arg, sizeof(flags))) {
1821                 ret = -EFAULT;
1822                 goto out_drop_write;
1823         }
1824 
1825         if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1826                 ret = -EINVAL;
1827                 goto out_drop_write;
1828         }
1829 
1830         if (flags & ~BTRFS_SUBVOL_RDONLY) {
1831                 ret = -EOPNOTSUPP;
1832                 goto out_drop_write;
1833         }
1834 
1835         down_write(&fs_info->subvol_sem);
1836 
1837         /* nothing to do */
1838         if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1839                 goto out_drop_sem;
1840 
1841         root_flags = btrfs_root_flags(&root->root_item);
1842         if (flags & BTRFS_SUBVOL_RDONLY) {
1843                 btrfs_set_root_flags(&root->root_item,
1844                                      root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1845         } else {
1846                 /*
1847                  * Block RO -> RW transition if this subvolume is involved in
1848                  * send
1849                  */
1850                 spin_lock(&root->root_item_lock);
1851                 if (root->send_in_progress == 0) {
1852                         btrfs_set_root_flags(&root->root_item,
1853                                      root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1854                         spin_unlock(&root->root_item_lock);
1855                 } else {
1856                         spin_unlock(&root->root_item_lock);
1857                         btrfs_warn(fs_info,
1858                                    "Attempt to set subvolume %llu read-write during send",
1859                                    root->root_key.objectid);
1860                         ret = -EPERM;
1861                         goto out_drop_sem;
1862                 }
1863         }
1864 
1865         trans = btrfs_start_transaction(root, 1);
1866         if (IS_ERR(trans)) {
1867                 ret = PTR_ERR(trans);
1868                 goto out_reset;
1869         }
1870 
1871         ret = btrfs_update_root(trans, fs_info->tree_root,
1872                                 &root->root_key, &root->root_item);
1873 
1874         btrfs_commit_transaction(trans);
1875 out_reset:
1876         if (ret)
1877                 btrfs_set_root_flags(&root->root_item, root_flags);
1878 out_drop_sem:
1879         up_write(&fs_info->subvol_sem);
1880 out_drop_write:
1881         mnt_drop_write_file(file);
1882 out:
1883         return ret;
1884 }
1885 
1886 /*
1887  * helper to check if the subvolume references other subvolumes
1888  */
1889 static noinline int may_destroy_subvol(struct btrfs_root *root)
1890 {
1891         struct btrfs_fs_info *fs_info = root->fs_info;
1892         struct btrfs_path *path;
1893         struct btrfs_dir_item *di;
1894         struct btrfs_key key;
1895         u64 dir_id;
1896         int ret;
1897 
1898         path = btrfs_alloc_path();
1899         if (!path)
1900                 return -ENOMEM;
1901 
1902         /* Make sure this root isn't set as the default subvol */
1903         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1904         di = btrfs_lookup_dir_item(NULL, fs_info->tree_root, path,
1905                                    dir_id, "default", 7, 0);
1906         if (di && !IS_ERR(di)) {
1907                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
1908                 if (key.objectid == root->root_key.objectid) {
1909                         ret = -EPERM;
1910                         btrfs_err(fs_info,
1911                                   "deleting default subvolume %llu is not allowed",
1912                                   key.objectid);
1913                         goto out;
1914                 }
1915                 btrfs_release_path(path);
1916         }
1917 
1918         key.objectid = root->root_key.objectid;
1919         key.type = BTRFS_ROOT_REF_KEY;
1920         key.offset = (u64)-1;
1921 
1922         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
1923         if (ret < 0)
1924                 goto out;
1925         BUG_ON(ret == 0);
1926 
1927         ret = 0;
1928         if (path->slots[0] > 0) {
1929                 path->slots[0]--;
1930                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1931                 if (key.objectid == root->root_key.objectid &&
1932                     key.type == BTRFS_ROOT_REF_KEY)
1933                         ret = -ENOTEMPTY;
1934         }
1935 out:
1936         btrfs_free_path(path);
1937         return ret;
1938 }
1939 
1940 static noinline int key_in_sk(struct btrfs_key *key,
1941                               struct btrfs_ioctl_search_key *sk)
1942 {
1943         struct btrfs_key test;
1944         int ret;
1945 
1946         test.objectid = sk->min_objectid;
1947         test.type = sk->min_type;
1948         test.offset = sk->min_offset;
1949 
1950         ret = btrfs_comp_cpu_keys(key, &test);
1951         if (ret < 0)
1952                 return 0;
1953 
1954         test.objectid = sk->max_objectid;
1955         test.type = sk->max_type;
1956         test.offset = sk->max_offset;
1957 
1958         ret = btrfs_comp_cpu_keys(key, &test);
1959         if (ret > 0)
1960                 return 0;
1961         return 1;
1962 }
1963 
1964 static noinline int copy_to_sk(struct btrfs_path *path,
1965                                struct btrfs_key *key,
1966                                struct btrfs_ioctl_search_key *sk,
1967                                size_t *buf_size,
1968                                char __user *ubuf,
1969                                unsigned long *sk_offset,
1970                                int *num_found)
1971 {
1972         u64 found_transid;
1973         struct extent_buffer *leaf;
1974         struct btrfs_ioctl_search_header sh;
1975         struct btrfs_key test;
1976         unsigned long item_off;
1977         unsigned long item_len;
1978         int nritems;
1979         int i;
1980         int slot;
1981         int ret = 0;
1982 
1983         leaf = path->nodes[0];
1984         slot = path->slots[0];
1985         nritems = btrfs_header_nritems(leaf);
1986 
1987         if (btrfs_header_generation(leaf) > sk->max_transid) {
1988                 i = nritems;
1989                 goto advance_key;
1990         }
1991         found_transid = btrfs_header_generation(leaf);
1992 
1993         for (i = slot; i < nritems; i++) {
1994                 item_off = btrfs_item_ptr_offset(leaf, i);
1995                 item_len = btrfs_item_size_nr(leaf, i);
1996 
1997                 btrfs_item_key_to_cpu(leaf, key, i);
1998                 if (!key_in_sk(key, sk))
1999                         continue;
2000 
2001                 if (sizeof(sh) + item_len > *buf_size) {
2002                         if (*num_found) {
2003                                 ret = 1;
2004                                 goto out;
2005                         }
2006 
2007                         /*
2008                          * return one empty item back for v1, which does not
2009                          * handle -EOVERFLOW
2010                          */
2011 
2012                         *buf_size = sizeof(sh) + item_len;
2013                         item_len = 0;
2014                         ret = -EOVERFLOW;
2015                 }
2016 
2017                 if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
2018                         ret = 1;
2019                         goto out;
2020                 }
2021 
2022                 sh.objectid = key->objectid;
2023                 sh.offset = key->offset;
2024                 sh.type = key->type;
2025                 sh.len = item_len;
2026                 sh.transid = found_transid;
2027 
2028                 /* copy search result header */
2029                 if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
2030                         ret = -EFAULT;
2031                         goto out;
2032                 }
2033 
2034                 *sk_offset += sizeof(sh);
2035 
2036                 if (item_len) {
2037                         char __user *up = ubuf + *sk_offset;
2038                         /* copy the item */
2039                         if (read_extent_buffer_to_user(leaf, up,
2040                                                        item_off, item_len)) {
2041                                 ret = -EFAULT;
2042                                 goto out;
2043                         }
2044 
2045                         *sk_offset += item_len;
2046                 }
2047                 (*num_found)++;
2048 
2049                 if (ret) /* -EOVERFLOW from above */
2050                         goto out;
2051 
2052                 if (*num_found >= sk->nr_items) {
2053                         ret = 1;
2054                         goto out;
2055                 }
2056         }
2057 advance_key:
2058         ret = 0;
2059         test.objectid = sk->max_objectid;
2060         test.type = sk->max_type;
2061         test.offset = sk->max_offset;
2062         if (btrfs_comp_cpu_keys(key, &test) >= 0)
2063                 ret = 1;
2064         else if (key->offset < (u64)-1)
2065                 key->offset++;
2066         else if (key->type < (u8)-1) {
2067                 key->offset = 0;
2068                 key->type++;
2069         } else if (key->objectid < (u64)-1) {
2070                 key->offset = 0;
2071                 key->type = 0;
2072                 key->objectid++;
2073         } else
2074                 ret = 1;
2075 out:
2076         /*
2077          *  0: all items from this leaf copied, continue with next
2078          *  1: * more items can be copied, but unused buffer is too small
2079          *     * all items were found
2080          *     Either way, it will stops the loop which iterates to the next
2081          *     leaf
2082          *  -EOVERFLOW: item was to large for buffer
2083          *  -EFAULT: could not copy extent buffer back to userspace
2084          */
2085         return ret;
2086 }
2087 
2088 static noinline int search_ioctl(struct inode *inode,
2089                                  struct btrfs_ioctl_search_key *sk,
2090                                  size_t *buf_size,
2091                                  char __user *ubuf)
2092 {
2093         struct btrfs_fs_info *info = btrfs_sb(inode->i_sb);
2094         struct btrfs_root *root;
2095         struct btrfs_key key;
2096         struct btrfs_path *path;
2097         int ret;
2098         int num_found = 0;
2099         unsigned long sk_offset = 0;
2100 
2101         if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
2102                 *buf_size = sizeof(struct btrfs_ioctl_search_header);
2103                 return -EOVERFLOW;
2104         }
2105 
2106         path = btrfs_alloc_path();
2107         if (!path)
2108                 return -ENOMEM;
2109 
2110         if (sk->tree_id == 0) {
2111                 /* search the root of the inode that was passed */
2112                 root = BTRFS_I(inode)->root;
2113         } else {
2114                 key.objectid = sk->tree_id;
2115                 key.type = BTRFS_ROOT_ITEM_KEY;
2116                 key.offset = (u64)-1;
2117                 root = btrfs_read_fs_root_no_name(info, &key);
2118                 if (IS_ERR(root)) {
2119                         btrfs_free_path(path);
2120                         return -ENOENT;
2121                 }
2122         }
2123 
2124         key.objectid = sk->min_objectid;
2125         key.type = sk->min_type;
2126         key.offset = sk->min_offset;
2127 
2128         while (1) {
2129                 ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2130                 if (ret != 0) {
2131                         if (ret > 0)
2132                                 ret = 0;
2133                         goto err;
2134                 }
2135                 ret = copy_to_sk(path, &key, sk, buf_size, ubuf,
2136                                  &sk_offset, &num_found);
2137                 btrfs_release_path(path);
2138                 if (ret)
2139                         break;
2140 
2141         }
2142         if (ret > 0)
2143                 ret = 0;
2144 err:
2145         sk->nr_items = num_found;
2146         btrfs_free_path(path);
2147         return ret;
2148 }
2149 
2150 static noinline int btrfs_ioctl_tree_search(struct file *file,
2151                                            void __user *argp)
2152 {
2153         struct btrfs_ioctl_search_args __user *uargs;
2154         struct btrfs_ioctl_search_key sk;
2155         struct inode *inode;
2156         int ret;
2157         size_t buf_size;
2158 
2159         if (!capable(CAP_SYS_ADMIN))
2160                 return -EPERM;
2161 
2162         uargs = (struct btrfs_ioctl_search_args __user *)argp;
2163 
2164         if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
2165                 return -EFAULT;
2166 
2167         buf_size = sizeof(uargs->buf);
2168 
2169         inode = file_inode(file);
2170         ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
2171 
2172         /*
2173          * In the origin implementation an overflow is handled by returning a
2174          * search header with a len of zero, so reset ret.
2175          */
2176         if (ret == -EOVERFLOW)
2177                 ret = 0;
2178 
2179         if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
2180                 ret = -EFAULT;
2181         return ret;
2182 }
2183 
2184 static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
2185                                                void __user *argp)
2186 {
2187         struct btrfs_ioctl_search_args_v2 __user *uarg;
2188         struct btrfs_ioctl_search_args_v2 args;
2189         struct inode *inode;
2190         int ret;
2191         size_t buf_size;
2192         const size_t buf_limit = SZ_16M;
2193 
2194         if (!capable(CAP_SYS_ADMIN))
2195                 return -EPERM;
2196 
2197         /* copy search header and buffer size */
2198         uarg = (struct btrfs_ioctl_search_args_v2 __user *)argp;
2199         if (copy_from_user(&args, uarg, sizeof(args)))
2200                 return -EFAULT;
2201 
2202         buf_size = args.buf_size;
2203 
2204         if (buf_size < sizeof(struct btrfs_ioctl_search_header))
2205                 return -EOVERFLOW;
2206 
2207         /* limit result size to 16MB */
2208         if (buf_size > buf_limit)
2209                 buf_size = buf_limit;
2210 
2211         inode = file_inode(file);
2212         ret = search_ioctl(inode, &args.key, &buf_size,
2213                            (char *)(&uarg->buf[0]));
2214         if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
2215                 ret = -EFAULT;
2216         else if (ret == -EOVERFLOW &&
2217                 copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
2218                 ret = -EFAULT;
2219 
2220         return ret;
2221 }
2222 
2223 /*
2224  * Search INODE_REFs to identify path name of 'dirid' directory
2225  * in a 'tree_id' tree. and sets path name to 'name'.
2226  */
2227 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2228                                 u64 tree_id, u64 dirid, char *name)
2229 {
2230         struct btrfs_root *root;
2231         struct btrfs_key key;
2232         char *ptr;
2233         int ret = -1;
2234         int slot;
2235         int len;
2236         int total_len = 0;
2237         struct btrfs_inode_ref *iref;
2238         struct extent_buffer *l;
2239         struct btrfs_path *path;
2240 
2241         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2242                 name[0]='\0';
2243                 return 0;
2244         }
2245 
2246         path = btrfs_alloc_path();
2247         if (!path)
2248                 return -ENOMEM;
2249 
2250         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
2251 
2252         key.objectid = tree_id;
2253         key.type = BTRFS_ROOT_ITEM_KEY;
2254         key.offset = (u64)-1;
2255         root = btrfs_read_fs_root_no_name(info, &key);
2256         if (IS_ERR(root)) {
2257                 btrfs_err(info, "could not find root %llu", tree_id);
2258                 ret = -ENOENT;
2259                 goto out;
2260         }
2261 
2262         key.objectid = dirid;
2263         key.type = BTRFS_INODE_REF_KEY;
2264         key.offset = (u64)-1;
2265 
2266         while (1) {
2267                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2268                 if (ret < 0)
2269                         goto out;
2270                 else if (ret > 0) {
2271                         ret = btrfs_previous_item(root, path, dirid,
2272                                                   BTRFS_INODE_REF_KEY);
2273                         if (ret < 0)
2274                                 goto out;
2275                         else if (ret > 0) {
2276                                 ret = -ENOENT;
2277                                 goto out;
2278                         }
2279                 }
2280 
2281                 l = path->nodes[0];
2282                 slot = path->slots[0];
2283                 btrfs_item_key_to_cpu(l, &key, slot);
2284 
2285                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2286                 len = btrfs_inode_ref_name_len(l, iref);
2287                 ptr -= len + 1;
2288                 total_len += len + 1;
2289                 if (ptr < name) {
2290                         ret = -ENAMETOOLONG;
2291                         goto out;
2292                 }
2293 
2294                 *(ptr + len) = '/';
2295                 read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2296 
2297                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2298                         break;
2299 
2300                 btrfs_release_path(path);
2301                 key.objectid = key.offset;
2302                 key.offset = (u64)-1;
2303                 dirid = key.objectid;
2304         }
2305         memmove(name, ptr, total_len);
2306         name[total_len] = '\0';
2307         ret = 0;
2308 out:
2309         btrfs_free_path(path);
2310         return ret;
2311 }
2312 
2313 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2314                                            void __user *argp)
2315 {
2316          struct btrfs_ioctl_ino_lookup_args *args;
2317          struct inode *inode;
2318         int ret = 0;
2319 
2320         args = memdup_user(argp, sizeof(*args));
2321         if (IS_ERR(args))
2322                 return PTR_ERR(args);
2323 
2324         inode = file_inode(file);
2325 
2326         /*
2327          * Unprivileged query to obtain the containing subvolume root id. The
2328          * path is reset so it's consistent with btrfs_search_path_in_tree.
2329          */
2330         if (args->treeid == 0)
2331                 args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2332 
2333         if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2334                 args->name[0] = 0;
2335                 goto out;
2336         }
2337 
2338         if (!capable(CAP_SYS_ADMIN)) {
2339                 ret = -EPERM;
2340                 goto out;
2341         }
2342 
2343         ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2344                                         args->treeid, args->objectid,
2345                                         args->name);
2346 
2347 out:
2348         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2349                 ret = -EFAULT;
2350 
2351         kfree(args);
2352         return ret;
2353 }
2354 
2355 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2356                                              void __user *arg)
2357 {
2358         struct dentry *parent = file->f_path.dentry;
2359         struct btrfs_fs_info *fs_info = btrfs_sb(parent->d_sb);
2360         struct dentry *dentry;
2361         struct inode *dir = d_inode(parent);
2362         struct inode *inode;
2363         struct btrfs_root *root = BTRFS_I(dir)->root;
2364         struct btrfs_root *dest = NULL;
2365         struct btrfs_ioctl_vol_args *vol_args;
2366         struct btrfs_trans_handle *trans;
2367         struct btrfs_block_rsv block_rsv;
2368         u64 root_flags;
2369         u64 qgroup_reserved;
2370         int namelen;
2371         int ret;
2372         int err = 0;
2373 
2374         if (!S_ISDIR(dir->i_mode))
2375                 return -ENOTDIR;
2376 
2377         vol_args = memdup_user(arg, sizeof(*vol_args));
2378         if (IS_ERR(vol_args))
2379                 return PTR_ERR(vol_args);
2380 
2381         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2382         namelen = strlen(vol_args->name);
2383         if (strchr(vol_args->name, '/') ||
2384             strncmp(vol_args->name, "..", namelen) == 0) {
2385                 err = -EINVAL;
2386                 goto out;
2387         }
2388 
2389         err = mnt_want_write_file(file);
2390         if (err)
2391                 goto out;
2392 
2393 
2394         err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
2395         if (err == -EINTR)
2396                 goto out_drop_write;
2397         dentry = lookup_one_len(vol_args->name, parent, namelen);
2398         if (IS_ERR(dentry)) {
2399                 err = PTR_ERR(dentry);
2400                 goto out_unlock_dir;
2401         }
2402 
2403         if (d_really_is_negative(dentry)) {
2404                 err = -ENOENT;
2405                 goto out_dput;
2406         }
2407 
2408         inode = d_inode(dentry);
2409         dest = BTRFS_I(inode)->root;
2410         if (!capable(CAP_SYS_ADMIN)) {
2411                 /*
2412                  * Regular user.  Only allow this with a special mount
2413                  * option, when the user has write+exec access to the
2414                  * subvol root, and when rmdir(2) would have been
2415                  * allowed.
2416                  *
2417                  * Note that this is _not_ check that the subvol is
2418                  * empty or doesn't contain data that we wouldn't
2419                  * otherwise be able to delete.
2420                  *
2421                  * Users who want to delete empty subvols should try
2422                  * rmdir(2).
2423                  */
2424                 err = -EPERM;
2425                 if (!btrfs_test_opt(fs_info, USER_SUBVOL_RM_ALLOWED))
2426                         goto out_dput;
2427 
2428                 /*
2429                  * Do not allow deletion if the parent dir is the same
2430                  * as the dir to be deleted.  That means the ioctl
2431                  * must be called on the dentry referencing the root
2432                  * of the subvol, not a random directory contained
2433                  * within it.
2434                  */
2435                 err = -EINVAL;
2436                 if (root == dest)
2437                         goto out_dput;
2438 
2439                 err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2440                 if (err)
2441                         goto out_dput;
2442         }
2443 
2444         /* check if subvolume may be deleted by a user */
2445         err = btrfs_may_delete(dir, dentry, 1);
2446         if (err)
2447                 goto out_dput;
2448 
2449         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2450                 err = -EINVAL;
2451                 goto out_dput;
2452         }
2453 
2454         inode_lock(inode);
2455 
2456         /*
2457          * Don't allow to delete a subvolume with send in progress. This is
2458          * inside the i_mutex so the error handling that has to drop the bit
2459          * again is not run concurrently.
2460          */
2461         spin_lock(&dest->root_item_lock);
2462         root_flags = btrfs_root_flags(&dest->root_item);
2463         if (dest->send_in_progress == 0) {
2464                 btrfs_set_root_flags(&dest->root_item,
2465                                 root_flags | BTRFS_ROOT_SUBVOL_DEAD);
2466                 spin_unlock(&dest->root_item_lock);
2467         } else {
2468                 spin_unlock(&dest->root_item_lock);
2469                 btrfs_warn(fs_info,
2470                            "Attempt to delete subvolume %llu during send",
2471                            dest->root_key.objectid);
2472                 err = -EPERM;
2473                 goto out_unlock_inode;
2474         }
2475 
2476         down_write(&fs_info->subvol_sem);
2477 
2478         err = may_destroy_subvol(dest);
2479         if (err)
2480                 goto out_up_write;
2481 
2482         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
2483         /*
2484          * One for dir inode, two for dir entries, two for root
2485          * ref/backref.
2486          */
2487         err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
2488                                                5, &qgroup_reserved, true);
2489         if (err)
2490                 goto out_up_write;
2491 
2492         trans = btrfs_start_transaction(root, 0);
2493         if (IS_ERR(trans)) {
2494                 err = PTR_ERR(trans);
2495                 goto out_release;
2496         }
2497         trans->block_rsv = &block_rsv;
2498         trans->bytes_reserved = block_rsv.size;
2499 
2500         btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
2501 
2502         ret = btrfs_unlink_subvol(trans, root, dir,
2503                                 dest->root_key.objectid,
2504                                 dentry->d_name.name,
2505                                 dentry->d_name.len);
2506         if (ret) {
2507                 err = ret;
2508                 btrfs_abort_transaction(trans, ret);
2509                 goto out_end_trans;
2510         }
2511 
2512         btrfs_record_root_in_trans(trans, dest);
2513 
2514         memset(&dest->root_item.drop_progress, 0,
2515                 sizeof(dest->root_item.drop_progress));
2516         dest->root_item.drop_level = 0;
2517         btrfs_set_root_refs(&dest->root_item, 0);
2518 
2519         if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
2520                 ret = btrfs_insert_orphan_item(trans,
2521                                         fs_info->tree_root,
2522                                         dest->root_key.objectid);
2523                 if (ret) {
2524                         btrfs_abort_transaction(trans, ret);
2525                         err = ret;
2526                         goto out_end_trans;
2527                 }
2528         }
2529 
2530         ret = btrfs_uuid_tree_rem(trans, fs_info, dest->root_item.uuid,
2531                                   BTRFS_UUID_KEY_SUBVOL,
2532                                   dest->root_key.objectid);
2533         if (ret && ret != -ENOENT) {
2534                 btrfs_abort_transaction(trans, ret);
2535                 err = ret;
2536                 goto out_end_trans;
2537         }
2538         if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
2539                 ret = btrfs_uuid_tree_rem(trans, fs_info,
2540                                           dest->root_item.received_uuid,
2541                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
2542                                           dest->root_key.objectid);
2543                 if (ret && ret != -ENOENT) {
2544                         btrfs_abort_transaction(trans, ret);
2545                         err = ret;
2546                         goto out_end_trans;
2547                 }
2548         }
2549 
2550 out_end_trans:
2551         trans->block_rsv = NULL;
2552         trans->bytes_reserved = 0;
2553         ret = btrfs_end_transaction(trans);
2554         if (ret && !err)
2555                 err = ret;
2556         inode->i_flags |= S_DEAD;
2557 out_release:
2558         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
2559 out_up_write:
2560         up_write(&fs_info->subvol_sem);
2561         if (err) {
2562                 spin_lock(&dest->root_item_lock);
2563                 root_flags = btrfs_root_flags(&dest->root_item);
2564                 btrfs_set_root_flags(&dest->root_item,
2565                                 root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
2566                 spin_unlock(&dest->root_item_lock);
2567         }
2568 out_unlock_inode:
2569         inode_unlock(inode);
2570         if (!err) {
2571                 d_invalidate(dentry);
2572                 btrfs_invalidate_inodes(dest);
2573                 d_delete(dentry);
2574                 ASSERT(dest->send_in_progress == 0);
2575 
2576                 /* the last ref */
2577                 if (dest->ino_cache_inode) {
2578                         iput(dest->ino_cache_inode);
2579                         dest->ino_cache_inode = NULL;
2580                 }
2581         }
2582 out_dput:
2583         dput(dentry);
2584 out_unlock_dir:
2585         inode_unlock(dir);
2586 out_drop_write:
2587         mnt_drop_write_file(file);
2588 out:
2589         kfree(vol_args);
2590         return err;
2591 }
2592 
2593 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2594 {
2595         struct inode *inode = file_inode(file);
2596         struct btrfs_root *root = BTRFS_I(inode)->root;
2597         struct btrfs_ioctl_defrag_range_args *range;
2598         int ret;
2599 
2600         ret = mnt_want_write_file(file);
2601         if (ret)
2602                 return ret;
2603 
2604         if (btrfs_root_readonly(root)) {
2605                 ret = -EROFS;
2606                 goto out;
2607         }
2608 
2609         switch (inode->i_mode & S_IFMT) {
2610         case S_IFDIR:
2611                 if (!capable(CAP_SYS_ADMIN)) {
2612                         ret = -EPERM;
2613                         goto out;
2614                 }
2615                 ret = btrfs_defrag_root(root);
2616                 break;
2617         case S_IFREG:
2618                 if (!(file->f_mode & FMODE_WRITE)) {
2619                         ret = -EINVAL;
2620                         goto out;
2621                 }
2622 
2623                 range = kzalloc(sizeof(*range), GFP_KERNEL);
2624                 if (!range) {
2625                         ret = -ENOMEM;
2626                         goto out;
2627                 }
2628 
2629                 if (argp) {
2630                         if (copy_from_user(range, argp,
2631                                            sizeof(*range))) {
2632                                 ret = -EFAULT;
2633                                 kfree(range);
2634                                 goto out;
2635                         }
2636                         /* compression requires us to start the IO */
2637                         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2638                                 range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
2639                                 range->extent_thresh = (u32)-1;
2640                         }
2641                 } else {
2642                         /* the rest are all set to zero by kzalloc */
2643                         range->len = (u64)-1;
2644                 }
2645                 ret = btrfs_defrag_file(file_inode(file), file,
2646                                         range, 0, 0);
2647                 if (ret > 0)
2648                         ret = 0;
2649                 kfree(range);
2650                 break;
2651         default:
2652                 ret = -EINVAL;
2653         }
2654 out:
2655         mnt_drop_write_file(file);
2656         return ret;
2657 }
2658 
2659 static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
2660 {
2661         struct btrfs_ioctl_vol_args *vol_args;
2662         int ret;
2663 
2664         if (!capable(CAP_SYS_ADMIN))
2665                 return -EPERM;
2666 
2667         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags))
2668                 return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2669 
2670         mutex_lock(&fs_info->volume_mutex);
2671         vol_args = memdup_user(arg, sizeof(*vol_args));
2672         if (IS_ERR(vol_args)) {
2673                 ret = PTR_ERR(vol_args);
2674                 goto out;
2675         }
2676 
2677         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2678         ret = btrfs_init_new_device(fs_info, vol_args->name);
2679 
2680         if (!ret)
2681                 btrfs_info(fs_info, "disk added %s", vol_args->name);
2682 
2683         kfree(vol_args);
2684 out:
2685         mutex_unlock(&fs_info->volume_mutex);
2686         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
2687         return ret;
2688 }
2689 
2690 static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
2691 {
2692         struct inode *inode = file_inode(file);
2693         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2694         struct btrfs_ioctl_vol_args_v2 *vol_args;
2695         int ret;
2696 
2697         if (!capable(CAP_SYS_ADMIN))
2698                 return -EPERM;
2699 
2700         ret = mnt_want_write_file(file);
2701         if (ret)
2702                 return ret;
2703 
2704         vol_args = memdup_user(arg, sizeof(*vol_args));
2705         if (IS_ERR(vol_args)) {
2706                 ret = PTR_ERR(vol_args);
2707                 goto err_drop;
2708         }
2709 
2710         /* Check for compatibility reject unknown flags */
2711         if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED)
2712                 return -EOPNOTSUPP;
2713 
2714         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
2715                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2716                 goto out;
2717         }
2718 
2719         mutex_lock(&fs_info->volume_mutex);
2720         if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
2721                 ret = btrfs_rm_device(fs_info, NULL, vol_args->devid);
2722         } else {
2723                 vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
2724                 ret = btrfs_rm_device(fs_info, vol_args->name, 0);
2725         }
2726         mutex_unlock(&fs_info->volume_mutex);
2727         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
2728 
2729         if (!ret) {
2730                 if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
2731                         btrfs_info(fs_info, "device deleted: id %llu",
2732                                         vol_args->devid);
2733                 else
2734                         btrfs_info(fs_info, "device deleted: %s",
2735                                         vol_args->name);
2736         }
2737 out:
2738         kfree(vol_args);
2739 err_drop:
2740         mnt_drop_write_file(file);
2741         return ret;
2742 }
2743 
2744 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
2745 {
2746         struct inode *inode = file_inode(file);
2747         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2748         struct btrfs_ioctl_vol_args *vol_args;
2749         int ret;
2750 
2751         if (!capable(CAP_SYS_ADMIN))
2752                 return -EPERM;
2753 
2754         ret = mnt_want_write_file(file);
2755         if (ret)
2756                 return ret;
2757 
2758         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
2759                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2760                 goto out_drop_write;
2761         }
2762 
2763         vol_args = memdup_user(arg, sizeof(*vol_args));
2764         if (IS_ERR(vol_args)) {
2765                 ret = PTR_ERR(vol_args);
2766                 goto out;
2767         }
2768 
2769         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2770         mutex_lock(&fs_info->volume_mutex);
2771         ret = btrfs_rm_device(fs_info, vol_args->name, 0);
2772         mutex_unlock(&fs_info->volume_mutex);
2773 
2774         if (!ret)
2775                 btrfs_info(fs_info, "disk deleted %s", vol_args->name);
2776         kfree(vol_args);
2777 out:
2778         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
2779 out_drop_write:
2780         mnt_drop_write_file(file);
2781 
2782         return ret;
2783 }
2784 
2785 static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info,
2786                                 void __user *arg)
2787 {
2788         struct btrfs_ioctl_fs_info_args *fi_args;
2789         struct btrfs_device *device;
2790         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2791         int ret = 0;
2792 
2793         fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
2794         if (!fi_args)
2795                 return -ENOMEM;
2796 
2797         mutex_lock(&fs_devices->device_list_mutex);
2798         fi_args->num_devices = fs_devices->num_devices;
2799         memcpy(&fi_args->fsid, fs_info->fsid, sizeof(fi_args->fsid));
2800 
2801         list_for_each_entry(device, &fs_devices->devices, dev_list) {
2802                 if (device->devid > fi_args->max_id)
2803                         fi_args->max_id = device->devid;
2804         }
2805         mutex_unlock(&fs_devices->device_list_mutex);
2806 
2807         fi_args->nodesize = fs_info->super_copy->nodesize;
2808         fi_args->sectorsize = fs_info->super_copy->sectorsize;
2809         fi_args->clone_alignment = fs_info->super_copy->sectorsize;
2810 
2811         if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
2812                 ret = -EFAULT;
2813 
2814         kfree(fi_args);
2815         return ret;
2816 }
2817 
2818 static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
2819                                  void __user *arg)
2820 {
2821         struct btrfs_ioctl_dev_info_args *di_args;
2822         struct btrfs_device *dev;
2823         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2824         int ret = 0;
2825         char *s_uuid = NULL;
2826 
2827         di_args = memdup_user(arg, sizeof(*di_args));
2828         if (IS_ERR(di_args))
2829                 return PTR_ERR(di_args);
2830 
2831         if (!btrfs_is_empty_uuid(di_args->uuid))
2832                 s_uuid = di_args->uuid;
2833 
2834         mutex_lock(&fs_devices->device_list_mutex);
2835         dev = btrfs_find_device(fs_info, di_args->devid, s_uuid, NULL);
2836 
2837         if (!dev) {
2838                 ret = -ENODEV;
2839                 goto out;
2840         }
2841 
2842         di_args->devid = dev->devid;
2843         di_args->bytes_used = btrfs_device_get_bytes_used(dev);
2844         di_args->total_bytes = btrfs_device_get_total_bytes(dev);
2845         memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2846         if (dev->name) {
2847                 struct rcu_string *name;
2848 
2849                 rcu_read_lock();
2850                 name = rcu_dereference(dev->name);
2851                 strncpy(di_args->path, name->str, sizeof(di_args->path));
2852                 rcu_read_unlock();
2853                 di_args->path[sizeof(di_args->path) - 1] = 0;
2854         } else {
2855                 di_args->path[0] = '\0';
2856         }
2857 
2858 out:
2859         mutex_unlock(&fs_devices->device_list_mutex);
2860         if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2861                 ret = -EFAULT;
2862 
2863         kfree(di_args);
2864         return ret;
2865 }
2866 
2867 static struct page *extent_same_get_page(struct inode *inode, pgoff_t index)
2868 {
2869         struct page *page;
2870 
2871         page = grab_cache_page(inode->i_mapping, index);
2872         if (!page)
2873                 return ERR_PTR(-ENOMEM);
2874 
2875         if (!PageUptodate(page)) {
2876                 int ret;
2877 
2878                 ret = btrfs_readpage(NULL, page);
2879                 if (ret)
2880                         return ERR_PTR(ret);
2881                 lock_page(page);
2882                 if (!PageUptodate(page)) {
2883                         unlock_page(page);
2884                         put_page(page);
2885                         return ERR_PTR(-EIO);
2886                 }
2887                 if (page->mapping != inode->i_mapping) {
2888                         unlock_page(page);
2889                         put_page(page);
2890                         return ERR_PTR(-EAGAIN);
2891                 }
2892         }
2893 
2894         return page;
2895 }
2896 
2897 static int gather_extent_pages(struct inode *inode, struct page **pages,
2898                                int num_pages, u64 off)
2899 {
2900         int i;
2901         pgoff_t index = off >> PAGE_SHIFT;
2902 
2903         for (i = 0; i < num_pages; i++) {
2904 again:
2905                 pages[i] = extent_same_get_page(inode, index + i);
2906                 if (IS_ERR(pages[i])) {
2907                         int err = PTR_ERR(pages[i]);
2908 
2909                         if (err == -EAGAIN)
2910                                 goto again;
2911                         pages[i] = NULL;
2912                         return err;
2913                 }
2914         }
2915         return 0;
2916 }
2917 
2918 static int lock_extent_range(struct inode *inode, u64 off, u64 len,
2919                              bool retry_range_locking)
2920 {
2921         /*
2922          * Do any pending delalloc/csum calculations on inode, one way or
2923          * another, and lock file content.
2924          * The locking order is:
2925          *
2926          *   1) pages
2927          *   2) range in the inode's io tree
2928          */
2929         while (1) {
2930                 struct btrfs_ordered_extent *ordered;
2931                 lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2932                 ordered = btrfs_lookup_first_ordered_extent(inode,
2933                                                             off + len - 1);
2934                 if ((!ordered ||
2935                      ordered->file_offset + ordered->len <= off ||
2936                      ordered->file_offset >= off + len) &&
2937                     !test_range_bit(&BTRFS_I(inode)->io_tree, off,
2938                                     off + len - 1, EXTENT_DELALLOC, 0, NULL)) {
2939                         if (ordered)
2940                                 btrfs_put_ordered_extent(ordered);
2941                         break;
2942                 }
2943                 unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
2944                 if (ordered)
2945                         btrfs_put_ordered_extent(ordered);
2946                 if (!retry_range_locking)
2947                         return -EAGAIN;
2948                 btrfs_wait_ordered_range(inode, off, len);
2949         }
2950         return 0;
2951 }
2952 
2953 static void btrfs_double_inode_unlock(struct inode *inode1, struct inode *inode2)
2954 {
2955         inode_unlock(inode1);
2956         inode_unlock(inode2);
2957 }
2958 
2959 static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
2960 {
2961         if (inode1 < inode2)
2962                 swap(inode1, inode2);
2963 
2964         inode_lock_nested(inode1, I_MUTEX_PARENT);
2965         inode_lock_nested(inode2, I_MUTEX_CHILD);
2966 }
2967 
2968 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
2969                                       struct inode *inode2, u64 loff2, u64 len)
2970 {
2971         unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
2972         unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
2973 }
2974 
2975 static int btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
2976                                     struct inode *inode2, u64 loff2, u64 len,
2977                                     bool retry_range_locking)
2978 {
2979         int ret;
2980 
2981         if (inode1 < inode2) {
2982                 swap(inode1, inode2);
2983                 swap(loff1, loff2);
2984         }
2985         ret = lock_extent_range(inode1, loff1, len, retry_range_locking);
2986         if (ret)
2987                 return ret;
2988         ret = lock_extent_range(inode2, loff2, len, retry_range_locking);
2989         if (ret)
2990                 unlock_extent(&BTRFS_I(inode1)->io_tree, loff1,
2991                               loff1 + len - 1);
2992         return ret;
2993 }
2994 
2995 struct cmp_pages {
2996         int             num_pages;
2997         struct page     **src_pages;
2998         struct page     **dst_pages;
2999 };
3000 
3001 static void btrfs_cmp_data_free(struct cmp_pages *cmp)
3002 {
3003         int i;
3004         struct page *pg;
3005 
3006         for (i = 0; i < cmp->num_pages; i++) {
3007                 pg = cmp->src_pages[i];
3008                 if (pg) {
3009                         unlock_page(pg);
3010                         put_page(pg);
3011                 }
3012                 pg = cmp->dst_pages[i];
3013                 if (pg) {
3014                         unlock_page(pg);
3015                         put_page(pg);
3016                 }
3017         }
3018         kfree(cmp->src_pages);
3019         kfree(cmp->dst_pages);
3020 }
3021 
3022 static int btrfs_cmp_data_prepare(struct inode *src, u64 loff,
3023                                   struct inode *dst, u64 dst_loff,
3024                                   u64 len, struct cmp_pages *cmp)
3025 {
3026         int ret;
3027         int num_pages = PAGE_ALIGN(len) >> PAGE_SHIFT;
3028         struct page **src_pgarr, **dst_pgarr;
3029 
3030         /*
3031          * We must gather up all the pages before we initiate our
3032          * extent locking. We use an array for the page pointers. Size
3033          * of the array is bounded by len, which is in turn bounded by
3034          * BTRFS_MAX_DEDUPE_LEN.
3035          */
3036         src_pgarr = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL);
3037         dst_pgarr = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL);
3038         if (!src_pgarr || !dst_pgarr) {
3039                 kfree(src_pgarr);
3040                 kfree(dst_pgarr);
3041                 return -ENOMEM;
3042         }
3043         cmp->num_pages = num_pages;
3044         cmp->src_pages = src_pgarr;
3045         cmp->dst_pages = dst_pgarr;
3046 
3047         /*
3048          * If deduping ranges in the same inode, locking rules make it mandatory
3049          * to always lock pages in ascending order to avoid deadlocks with
3050          * concurrent tasks (such as starting writeback/delalloc).
3051          */
3052         if (src == dst && dst_loff < loff) {
3053                 swap(src_pgarr, dst_pgarr);
3054                 swap(loff, dst_loff);
3055         }
3056 
3057         ret = gather_extent_pages(src, src_pgarr, cmp->num_pages, loff);
3058         if (ret)
3059                 goto out;
3060 
3061         ret = gather_extent_pages(dst, dst_pgarr, cmp->num_pages, dst_loff);
3062 
3063 out:
3064         if (ret)
3065                 btrfs_cmp_data_free(cmp);
3066         return ret;
3067 }
3068 
3069 static int btrfs_cmp_data(u64 len, struct cmp_pages *cmp)
3070 {
3071         int ret = 0;
3072         int i;
3073         struct page *src_page, *dst_page;
3074         unsigned int cmp_len = PAGE_SIZE;
3075         void *addr, *dst_addr;
3076 
3077         i = 0;
3078         while (len) {
3079                 if (len < PAGE_SIZE)
3080                         cmp_len = len;
3081 
3082                 BUG_ON(i >= cmp->num_pages);
3083 
3084                 src_page = cmp->src_pages[i];
3085                 dst_page = cmp->dst_pages[i];
3086                 ASSERT(PageLocked(src_page));
3087                 ASSERT(PageLocked(dst_page));
3088 
3089                 addr = kmap_atomic(src_page);
3090                 dst_addr = kmap_atomic(dst_page);
3091 
3092                 flush_dcache_page(src_page);
3093                 flush_dcache_page(dst_page);
3094 
3095                 if (memcmp(addr, dst_addr, cmp_len))
3096                         ret = -EBADE;
3097 
3098                 kunmap_atomic(addr);
3099                 kunmap_atomic(dst_addr);
3100 
3101                 if (ret)
3102                         break;
3103 
3104                 len -= cmp_len;
3105                 i++;
3106         }
3107 
3108         return ret;
3109 }
3110 
3111 static int extent_same_check_offsets(struct inode *inode, u64 off, u64 *plen,
3112                                      u64 olen)
3113 {
3114         u64 len = *plen;
3115         u64 bs = BTRFS_I(inode)->root->fs_info->sb->s_blocksize;
3116 
3117         if (off + olen > inode->i_size || off + olen < off)
3118                 return -EINVAL;
3119 
3120         /* if we extend to eof, continue to block boundary */
3121         if (off + len == inode->i_size)
3122                 *plen = len = ALIGN(inode->i_size, bs) - off;
3123 
3124         /* Check that we are block aligned - btrfs_clone() requires this */
3125         if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs))
3126                 return -EINVAL;
3127 
3128         return 0;
3129 }
3130 
3131 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
3132                              struct inode *dst, u64 dst_loff)
3133 {
3134         int ret;
3135         u64 len = olen;
3136         struct cmp_pages cmp;
3137         bool same_inode = (src == dst);
3138         u64 same_lock_start = 0;
3139         u64 same_lock_len = 0;
3140 
3141         if (len == 0)
3142                 return 0;
3143 
3144         if (same_inode)
3145                 inode_lock(src);
3146         else
3147                 btrfs_double_inode_lock(src, dst);
3148 
3149         ret = extent_same_check_offsets(src, loff, &len, olen);
3150         if (ret)
3151                 goto out_unlock;
3152 
3153         ret = extent_same_check_offsets(dst, dst_loff, &len, olen);
3154         if (ret)
3155                 goto out_unlock;
3156 
3157         if (same_inode) {
3158                 /*
3159                  * Single inode case wants the same checks, except we
3160                  * don't want our length pushed out past i_size as
3161                  * comparing that data range makes no sense.
3162                  *
3163                  * extent_same_check_offsets() will do this for an
3164                  * unaligned length at i_size, so catch it here and
3165                  * reject the request.
3166                  *
3167                  * This effectively means we require aligned extents
3168                  * for the single-inode case, whereas the other cases
3169                  * allow an unaligned length so long as it ends at
3170                  * i_size.
3171                  */
3172                 if (len != olen) {
3173                         ret = -EINVAL;
3174                         goto out_unlock;
3175                 }
3176 
3177                 /* Check for overlapping ranges */
3178                 if (dst_loff + len > loff && dst_loff < loff + len) {
3179                         ret = -EINVAL;
3180                         goto out_unlock;
3181                 }
3182 
3183                 same_lock_start = min_t(u64, loff, dst_loff);
3184                 same_lock_len = max_t(u64, loff, dst_loff) + len - same_lock_start;
3185         }
3186 
3187         /* don't make the dst file partly checksummed */
3188         if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3189             (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
3190                 ret = -EINVAL;
3191                 goto out_unlock;
3192         }
3193 
3194 again:
3195         ret = btrfs_cmp_data_prepare(src, loff, dst, dst_loff, olen, &cmp);
3196         if (ret)
3197                 goto out_unlock;
3198 
3199         if (same_inode)
3200                 ret = lock_extent_range(src, same_lock_start, same_lock_len,
3201                                         false);
3202         else
3203                 ret = btrfs_double_extent_lock(src, loff, dst, dst_loff, len,
3204                                                false);
3205         /*
3206          * If one of the inodes has dirty pages in the respective range or
3207          * ordered extents, we need to flush dellaloc and wait for all ordered
3208          * extents in the range. We must unlock the pages and the ranges in the
3209          * io trees to avoid deadlocks when flushing delalloc (requires locking
3210          * pages) and when waiting for ordered extents to complete (they require
3211          * range locking).
3212          */
3213         if (ret == -EAGAIN) {
3214                 /*
3215                  * Ranges in the io trees already unlocked. Now unlock all
3216                  * pages before waiting for all IO to complete.
3217                  */
3218                 btrfs_cmp_data_free(&cmp);
3219                 if (same_inode) {
3220                         btrfs_wait_ordered_range(src, same_lock_start,
3221                                                  same_lock_len);
3222                 } else {
3223                         btrfs_wait_ordered_range(src, loff, len);
3224                         btrfs_wait_ordered_range(dst, dst_loff, len);
3225                 }
3226                 goto again;
3227         }
3228         ASSERT(ret == 0);
3229         if (WARN_ON(ret)) {
3230                 /* ranges in the io trees already unlocked */
3231                 btrfs_cmp_data_free(&cmp);
3232                 return ret;
3233         }
3234 
3235         /* pass original length for comparison so we stay within i_size */
3236         ret = btrfs_cmp_data(olen, &cmp);
3237         if (ret == 0)
3238                 ret = btrfs_clone(src, dst, loff, olen, len, dst_loff, 1);
3239 
3240         if (same_inode)
3241                 unlock_extent(&BTRFS_I(src)->io_tree, same_lock_start,
3242                               same_lock_start + same_lock_len - 1);
3243         else
3244                 btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
3245 
3246         btrfs_cmp_data_free(&cmp);
3247 out_unlock:
3248         if (same_inode)
3249                 inode_unlock(src);
3250         else
3251                 btrfs_double_inode_unlock(src, dst);
3252 
3253         return ret;
3254 }
3255 
3256 #define BTRFS_MAX_DEDUPE_LEN    SZ_16M
3257 
3258 ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen,
3259                                 struct file *dst_file, u64 dst_loff)
3260 {
3261         struct inode *src = file_inode(src_file);
3262         struct inode *dst = file_inode(dst_file);
3263         u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
3264         ssize_t res;
3265 
3266         if (olen > BTRFS_MAX_DEDUPE_LEN)
3267                 olen = BTRFS_MAX_DEDUPE_LEN;
3268 
3269         if (WARN_ON_ONCE(bs < PAGE_SIZE)) {
3270                 /*
3271                  * Btrfs does not support blocksize < page_size. As a
3272                  * result, btrfs_cmp_data() won't correctly handle
3273                  * this situation without an update.
3274                  */
3275                 return -EINVAL;
3276         }
3277 
3278         res = btrfs_extent_same(src, loff, olen, dst, dst_loff);
3279         if (res)
3280                 return res;
3281         return olen;
3282 }
3283 
3284 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
3285                                      struct inode *inode,
3286                                      u64 endoff,
3287                                      const u64 destoff,
3288                                      const u64 olen,
3289                                      int no_time_update)
3290 {
3291         struct btrfs_root *root = BTRFS_I(inode)->root;
3292         int ret;
3293 
3294         inode_inc_iversion(inode);
3295         if (!no_time_update)
3296                 inode->i_mtime = inode->i_ctime = current_time(inode);
3297         /*
3298          * We round up to the block size at eof when determining which
3299          * extents to clone above, but shouldn't round up the file size.
3300          */
3301         if (endoff > destoff + olen)
3302                 endoff = destoff + olen;
3303         if (endoff > inode->i_size)
3304                 btrfs_i_size_write(BTRFS_I(inode), endoff);
3305 
3306         ret = btrfs_update_inode(trans, root, inode);
3307         if (ret) {
3308                 btrfs_abort_transaction(trans, ret);
3309                 btrfs_end_transaction(trans);
3310                 goto out;
3311         }
3312         ret = btrfs_end_transaction(trans);
3313 out:
3314         return ret;
3315 }
3316 
3317 static void clone_update_extent_map(struct btrfs_inode *inode,
3318                                     const struct btrfs_trans_handle *trans,
3319                                     const struct btrfs_path *path,
3320                                     const u64 hole_offset,
3321                                     const u64 hole_len)
3322 {
3323         struct extent_map_tree *em_tree = &inode->extent_tree;
3324         struct extent_map *em;
3325         int ret;
3326 
3327         em = alloc_extent_map();
3328         if (!em) {
3329                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
3330                 return;
3331         }
3332 
3333         if (path) {
3334                 struct btrfs_file_extent_item *fi;
3335 
3336                 fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
3337                                     struct btrfs_file_extent_item);
3338                 btrfs_extent_item_to_extent_map(inode, path, fi, false, em);
3339                 em->generation = -1;
3340                 if (btrfs_file_extent_type(path->nodes[0], fi) ==
3341                     BTRFS_FILE_EXTENT_INLINE)
3342                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3343                                         &inode->runtime_flags);
3344         } else {
3345                 em->start = hole_offset;
3346                 em->len = hole_len;
3347                 em->ram_bytes = em->len;
3348                 em->orig_start = hole_offset;
3349                 em->block_start = EXTENT_MAP_HOLE;
3350                 em->block_len = 0;
3351                 em->orig_block_len = 0;
3352                 em->compress_type = BTRFS_COMPRESS_NONE;
3353                 em->generation = trans->transid;
3354         }
3355 
3356         while (1) {
3357                 write_lock(&em_tree->lock);
3358                 ret = add_extent_mapping(em_tree, em, 1);
3359                 write_unlock(&em_tree->lock);
3360                 if (ret != -EEXIST) {
3361                         free_extent_map(em);
3362                         break;
3363                 }
3364                 btrfs_drop_extent_cache(inode, em->start,
3365                                         em->start + em->len - 1, 0);
3366         }
3367 
3368         if (ret)
3369                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
3370 }
3371 
3372 /*
3373  * Make sure we do not end up inserting an inline extent into a file that has
3374  * already other (non-inline) extents. If a file has an inline extent it can
3375  * not have any other extents and the (single) inline extent must start at the
3376  * file offset 0. Failing to respect these rules will lead to file corruption,
3377  * resulting in EIO errors on read/write operations, hitting BUG_ON's in mm, etc
3378  *
3379  * We can have extents that have been already written to disk or we can have
3380  * dirty ranges still in delalloc, in which case the extent maps and items are
3381  * created only when we run delalloc, and the delalloc ranges might fall outside
3382  * the range we are currently locking in the inode's io tree. So we check the
3383  * inode's i_size because of that (i_size updates are done while holding the
3384  * i_mutex, which we are holding here).
3385  * We also check to see if the inode has a size not greater than "datal" but has
3386  * extents beyond it, due to an fallocate with FALLOC_FL_KEEP_SIZE (and we are
3387  * protected against such concurrent fallocate calls by the i_mutex).
3388  *
3389  * If the file has no extents but a size greater than datal, do not allow the
3390  * copy because we would need turn the inline extent into a non-inline one (even
3391  * with NO_HOLES enabled). If we find our destination inode only has one inline
3392  * extent, just overwrite it with the source inline extent if its size is less
3393  * than the source extent's size, or we could copy the source inline extent's
3394  * data into the destination inode's inline extent if the later is greater then
3395  * the former.
3396  */
3397 static int clone_copy_inline_extent(struct inode *dst,
3398                                     struct btrfs_trans_handle *trans,
3399                                     struct btrfs_path *path,
3400                                     struct btrfs_key *new_key,
3401                                     const u64 drop_start,
3402                                     const u64 datal,
3403                                     const u64 skip,
3404                                     const u64 size,
3405                                     char *inline_data)
3406 {
3407         struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
3408         struct btrfs_root *root = BTRFS_I(dst)->root;
3409         const u64 aligned_end = ALIGN(new_key->offset + datal,
3410                                       fs_info->sectorsize);
3411         int ret;
3412         struct btrfs_key key;
3413 
3414         if (new_key->offset > 0)
3415                 return -EOPNOTSUPP;
3416 
3417         key.objectid = btrfs_ino(BTRFS_I(dst));
3418         key.type = BTRFS_EXTENT_DATA_KEY;
3419         key.offset = 0;
3420         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3421         if (ret < 0) {
3422                 return ret;
3423         } else if (ret > 0) {
3424                 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
3425                         ret = btrfs_next_leaf(root, path);
3426                         if (ret < 0)
3427                                 return ret;
3428                         else if (ret > 0)
3429                                 goto copy_inline_extent;
3430                 }
3431                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3432                 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
3433                     key.type == BTRFS_EXTENT_DATA_KEY) {
3434                         ASSERT(key.offset > 0);
3435                         return -EOPNOTSUPP;
3436                 }
3437         } else if (i_size_read(dst) <= datal) {
3438                 struct btrfs_file_extent_item *ei;
3439                 u64 ext_len;
3440 
3441                 /*
3442                  * If the file size is <= datal, make sure there are no other
3443                  * extents following (can happen do to an fallocate call with
3444                  * the flag FALLOC_FL_KEEP_SIZE).
3445                  */
3446                 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3447                                     struct btrfs_file_extent_item);
3448                 /*
3449                  * If it's an inline extent, it can not have other extents
3450                  * following it.
3451                  */
3452                 if (btrfs_file_extent_type(path->nodes[0], ei) ==
3453                     BTRFS_FILE_EXTENT_INLINE)
3454                         goto copy_inline_extent;
3455 
3456                 ext_len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
3457                 if (ext_len > aligned_end)
3458                         return -EOPNOTSUPP;
3459 
3460                 ret = btrfs_next_item(root, path);
3461                 if (ret < 0) {
3462                         return ret;
3463                 } else if (ret == 0) {
3464                         btrfs_item_key_to_cpu(path->nodes[0], &key,
3465                                               path->slots[0]);
3466                         if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
3467                             key.type == BTRFS_EXTENT_DATA_KEY)
3468                                 return -EOPNOTSUPP;
3469                 }
3470         }
3471 
3472 copy_inline_extent:
3473         /*
3474          * We have no extent items, or we have an extent at offset 0 which may
3475          * or may not be inlined. All these cases are dealt the same way.
3476          */
3477         if (i_size_read(dst) > datal) {
3478                 /*
3479                  * If the destination inode has an inline extent...
3480                  * This would require copying the data from the source inline
3481                  * extent into the beginning of the destination's inline extent.
3482                  * But this is really complex, both extents can be compressed
3483                  * or just one of them, which would require decompressing and
3484                  * re-compressing data (which could increase the new compressed
3485                  * size, not allowing the compressed data to fit anymore in an
3486                  * inline extent).
3487                  * So just don't support this case for now (it should be rare,
3488                  * we are not really saving space when cloning inline extents).
3489                  */
3490                 return -EOPNOTSUPP;
3491         }
3492 
3493         btrfs_release_path(path);
3494         ret = btrfs_drop_extents(trans, root, dst, drop_start, aligned_end, 1);
3495         if (ret)
3496                 return ret;
3497         ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
3498         if (ret)
3499                 return ret;
3500 
3501         if (skip) {
3502                 const u32 start = btrfs_file_extent_calc_inline_size(0);
3503 
3504                 memmove(inline_data + start, inline_data + start + skip, datal);
3505         }
3506 
3507         write_extent_buffer(path->nodes[0], inline_data,
3508                             btrfs_item_ptr_offset(path->nodes[0],
3509                                                   path->slots[0]),
3510                             size);
3511         inode_add_bytes(dst, datal);
3512 
3513         return 0;
3514 }
3515 
3516 /**
3517  * btrfs_clone() - clone a range from inode file to another
3518  *
3519  * @src: Inode to clone from
3520  * @inode: Inode to clone to
3521  * @off: Offset within source to start clone from
3522  * @olen: Original length, passed by user, of range to clone
3523  * @olen_aligned: Block-aligned value of olen
3524  * @destoff: Offset within @inode to start clone
3525  * @no_time_update: Whether to update mtime/ctime on the target inode
3526  */
3527 static int btrfs_clone(struct inode *src, struct inode *inode,
3528                        const u64 off, const u64 olen, const u64 olen_aligned,
3529                        const u64 destoff, int no_time_update)
3530 {
3531         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3532         struct btrfs_root *root = BTRFS_I(inode)->root;
3533         struct btrfs_path *path = NULL;
3534         struct extent_buffer *leaf;
3535         struct btrfs_trans_handle *trans;
3536         char *buf = NULL;
3537         struct btrfs_key key;
3538         u32 nritems;
3539         int slot;
3540         int ret;
3541         const u64 len = olen_aligned;
3542         u64 last_dest_end = destoff;
3543 
3544         ret = -ENOMEM;
3545         buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
3546         if (!buf)
3547                 return ret;
3548 
3549         path = btrfs_alloc_path();
3550         if (!path) {
3551                 kvfree(buf);
3552                 return ret;
3553         }
3554 
3555         path->reada = READA_FORWARD;
3556         /* clone data */
3557         key.objectid = btrfs_ino(BTRFS_I(src));
3558         key.type = BTRFS_EXTENT_DATA_KEY;
3559         key.offset = off;
3560 
3561         while (1) {
3562                 u64 next_key_min_offset = key.offset + 1;
3563 
3564                 /*
3565                  * note the key will change type as we walk through the
3566                  * tree.
3567                  */
3568                 path->leave_spinning = 1;
3569                 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
3570                                 0, 0);
3571                 if (ret < 0)
3572                         goto out;
3573                 /*
3574                  * First search, if no extent item that starts at offset off was
3575                  * found but the previous item is an extent item, it's possible
3576                  * it might overlap our target range, therefore process it.
3577                  */
3578                 if (key.offset == off && ret > 0 && path->slots[0] > 0) {
3579                         btrfs_item_key_to_cpu(path->nodes[0], &key,
3580                                               path->slots[0] - 1);
3581                         if (key.type == BTRFS_EXTENT_DATA_KEY)
3582                                 path->slots[0]--;
3583                 }
3584 
3585                 nritems = btrfs_header_nritems(path->nodes[0]);
3586 process_slot:
3587                 if (path->slots[0] >= nritems) {
3588                         ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
3589                         if (ret < 0)
3590                                 goto out;
3591                         if (ret > 0)
3592                                 break;
3593                         nritems = btrfs_header_nritems(path->nodes[0]);
3594                 }
3595                 leaf = path->nodes[0];
3596                 slot = path->slots[0];
3597 
3598                 btrfs_item_key_to_cpu(leaf, &key, slot);
3599                 if (key.type > BTRFS_EXTENT_DATA_KEY ||
3600                     key.objectid != btrfs_ino(BTRFS_I(src)))
3601                         break;
3602 
3603                 if (key.type == BTRFS_EXTENT_DATA_KEY) {
3604                         struct btrfs_file_extent_item *extent;
3605                         int type;
3606                         u32 size;
3607                         struct btrfs_key new_key;
3608                         u64 disko = 0, diskl = 0;
3609                         u64 datao = 0, datal = 0;
3610                         u8 comp;
3611                         u64 drop_start;
3612 
3613                         extent = btrfs_item_ptr(leaf, slot,
3614                                                 struct btrfs_file_extent_item);
3615                         comp = btrfs_file_extent_compression(leaf, extent);
3616                         type = btrfs_file_extent_type(leaf, extent);
3617                         if (type == BTRFS_FILE_EXTENT_REG ||
3618                             type == BTRFS_FILE_EXTENT_PREALLOC) {
3619                                 disko = btrfs_file_extent_disk_bytenr(leaf,
3620                                                                       extent);
3621                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
3622                                                                  extent);
3623                                 datao = btrfs_file_extent_offset(leaf, extent);
3624                                 datal = btrfs_file_extent_num_bytes(leaf,
3625                                                                     extent);
3626                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
3627                                 /* take upper bound, may be compressed */
3628                                 datal = btrfs_file_extent_ram_bytes(leaf,
3629                                                                     extent);
3630                         }
3631 
3632                         /*
3633                          * The first search might have left us at an extent
3634                          * item that ends before our target range's start, can
3635                          * happen if we have holes and NO_HOLES feature enabled.
3636                          */
3637                         if (key.offset + datal <= off) {
3638                                 path->slots[0]++;
3639                                 goto process_slot;
3640                         } else if (key.offset >= off + len) {
3641                                 break;
3642                         }
3643                         next_key_min_offset = key.offset + datal;
3644                         size = btrfs_item_size_nr(leaf, slot);
3645                         read_extent_buffer(leaf, buf,
3646                                            btrfs_item_ptr_offset(leaf, slot),
3647                                            size);
3648 
3649                         btrfs_release_path(path);
3650                         path->leave_spinning = 0;
3651 
3652                         memcpy(&new_key, &key, sizeof(new_key));
3653                         new_key.objectid = btrfs_ino(BTRFS_I(inode));
3654                         if (off <= key.offset)
3655                                 new_key.offset = key.offset + destoff - off;
3656                         else
3657                                 new_key.offset = destoff;
3658 
3659                         /*
3660                          * Deal with a hole that doesn't have an extent item
3661                          * that represents it (NO_HOLES feature enabled).
3662                          * This hole is either in the middle of the cloning
3663                          * range or at the beginning (fully overlaps it or
3664                          * partially overlaps it).
3665                          */
3666                         if (new_key.offset != last_dest_end)
3667                                 drop_start = last_dest_end;
3668                         else
3669                                 drop_start = new_key.offset;
3670 
3671                         /*
3672                          * 1 - adjusting old extent (we may have to split it)
3673                          * 1 - add new extent
3674                          * 1 - inode update
3675                          */
3676                         trans = btrfs_start_transaction(root, 3);
3677                         if (IS_ERR(trans)) {
3678                                 ret = PTR_ERR(trans);
3679                                 goto out;
3680                         }
3681 
3682                         if (type == BTRFS_FILE_EXTENT_REG ||
3683                             type == BTRFS_FILE_EXTENT_PREALLOC) {
3684                                 /*
3685                                  *    a  | --- range to clone ---|  b
3686                                  * | ------------- extent ------------- |
3687                                  */
3688 
3689                                 /* subtract range b */
3690                                 if (key.offset + datal > off + len)
3691                                         datal = off + len - key.offset;
3692 
3693                                 /* subtract range a */
3694                                 if (off > key.offset) {
3695                                         datao += off - key.offset;
3696                                         datal -= off - key.offset;
3697                                 }
3698 
3699                                 ret = btrfs_drop_extents(trans, root, inode,
3700                                                          drop_start,
3701                                                          new_key.offset + datal,
3702                                                          1);
3703                                 if (ret) {
3704                                         if (ret != -EOPNOTSUPP)
3705                                                 btrfs_abort_transaction(trans,
3706                                                                         ret);
3707                                         btrfs_end_transaction(trans);
3708                                         goto out;
3709                                 }
3710 
3711                                 ret = btrfs_insert_empty_item(trans, root, path,
3712                                                               &new_key, size);
3713                                 if (ret) {
3714                                         btrfs_abort_transaction(trans, ret);
3715                                         btrfs_end_transaction(trans);
3716                                         goto out;
3717                                 }
3718 
3719                                 leaf = path->nodes[0];
3720                                 slot = path->slots[0];
3721                                 write_extent_buffer(leaf, buf,
3722                                             btrfs_item_ptr_offset(leaf, slot),
3723                                             size);
3724 
3725                                 extent = btrfs_item_ptr(leaf, slot,
3726                                                 struct btrfs_file_extent_item);
3727 
3728                                 /* disko == 0 means it's a hole */
3729                                 if (!disko)
3730                                         datao = 0;
3731 
3732                                 btrfs_set_file_extent_offset(leaf, extent,
3733                                                              datao);
3734                                 btrfs_set_file_extent_num_bytes(leaf, extent,
3735                                                                 datal);
3736 
3737                                 if (disko) {
3738                                         inode_add_bytes(inode, datal);
3739                                         ret = btrfs_inc_extent_ref(trans,
3740                                                         fs_info,
3741                                                         disko, diskl, 0,
3742                                                         root->root_key.objectid,
3743                                                         btrfs_ino(BTRFS_I(inode)),
3744                                                         new_key.offset - datao);
3745                                         if (ret) {
3746                                                 btrfs_abort_transaction(trans,
3747                                                                         ret);
3748                                                 btrfs_end_transaction(trans);
3749                                                 goto out;
3750 
3751                                         }
3752                                 }
3753                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
3754                                 u64 skip = 0;
3755                                 u64 trim = 0;
3756 
3757                                 if (off > key.offset) {
3758                                         skip = off - key.offset;
3759                                         new_key.offset += skip;
3760                                 }
3761 
3762                                 if (key.offset + datal > off + len)
3763                                         trim = key.offset + datal - (off + len);
3764 
3765                                 if (comp && (skip || trim)) {
3766                                         ret = -EINVAL;
3767                                         btrfs_end_transaction(trans);
3768                                         goto out;
3769                                 }
3770                                 size -= skip + trim;
3771                                 datal -= skip + trim;
3772 
3773                                 ret = clone_copy_inline_extent(inode,
3774                                                                trans, path,
3775                                                                &new_key,
3776                                                                drop_start,
3777                                                                datal,
3778                                                                skip, size, buf);
3779                                 if (ret) {
3780                                         if (ret != -EOPNOTSUPP)
3781                                                 btrfs_abort_transaction(trans,
3782                                                                         ret);
3783                                         btrfs_end_transaction(trans);
3784                                         goto out;
3785                                 }
3786                                 leaf = path->nodes[0];
3787                                 slot = path->slots[0];
3788                         }
3789 
3790                         /* If we have an implicit hole (NO_HOLES feature). */
3791                         if (drop_start < new_key.offset)
3792                                 clone_update_extent_map(BTRFS_I(inode), trans,
3793                                                 NULL, drop_start,
3794                                                 new_key.offset - drop_start);
3795 
3796                         clone_update_extent_map(BTRFS_I(inode), trans,
3797                                         path, 0, 0);
3798 
3799                         btrfs_mark_buffer_dirty(leaf);
3800                         btrfs_release_path(path);
3801 
3802                         last_dest_end = ALIGN(new_key.offset + datal,
3803                                               fs_info->sectorsize);
3804                         ret = clone_finish_inode_update(trans, inode,
3805                                                         last_dest_end,
3806                                                         destoff, olen,
3807                                                         no_time_update);
3808                         if (ret)
3809                                 goto out;
3810                         if (new_key.offset + datal >= destoff + len)
3811                                 break;
3812                 }
3813                 btrfs_release_path(path);
3814                 key.offset = next_key_min_offset;
3815 
3816                 if (fatal_signal_pending(current)) {
3817                         ret = -EINTR;
3818                         goto out;
3819                 }
3820         }
3821         ret = 0;
3822 
3823         if (last_dest_end < destoff + len) {
3824                 /*
3825                  * We have an implicit hole (NO_HOLES feature is enabled) that
3826                  * fully or partially overlaps our cloning range at its end.
3827                  */
3828                 btrfs_release_path(path);
3829 
3830                 /*
3831                  * 1 - remove extent(s)
3832                  * 1 - inode update
3833                  */
3834                 trans = btrfs_start_transaction(root, 2);
3835                 if (IS_ERR(trans)) {
3836                         ret = PTR_ERR(trans);
3837                         goto out;
3838                 }
3839                 ret = btrfs_drop_extents(trans, root, inode,
3840                                          last_dest_end, destoff + len, 1);
3841                 if (ret) {
3842                         if (ret != -EOPNOTSUPP)
3843                                 btrfs_abort_transaction(trans, ret);
3844                         btrfs_end_transaction(trans);
3845                         goto out;
3846                 }
3847                 clone_update_extent_map(BTRFS_I(inode), trans, NULL,
3848                                 last_dest_end,
3849                                 destoff + len - last_dest_end);
3850                 ret = clone_finish_inode_update(trans, inode, destoff + len,
3851                                                 destoff, olen, no_time_update);
3852         }
3853 
3854 out:
3855         btrfs_free_path(path);
3856         kvfree(buf);
3857         return ret;
3858 }
3859 
3860 static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
3861                                         u64 off, u64 olen, u64 destoff)
3862 {
3863         struct inode *inode = file_inode(file);
3864         struct inode *src = file_inode(file_src);
3865         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3866         struct btrfs_root *root = BTRFS_I(inode)->root;
3867         int ret;
3868         u64 len = olen;
3869         u64 bs = fs_info->sb->s_blocksize;
3870         int same_inode = src == inode;
3871 
3872         /*
3873          * TODO:
3874          * - split compressed inline extents.  annoying: we need to
3875          *   decompress into destination's address_space (the file offset
3876          *   may change, so source mapping won't do), then recompress (or
3877          *   otherwise reinsert) a subrange.
3878          *
3879          * - split destination inode's inline extents.  The inline extents can
3880          *   be either compressed or non-compressed.
3881          */
3882 
3883         if (btrfs_root_readonly(root))
3884                 return -EROFS;
3885 
3886         if (file_src->f_path.mnt != file->f_path.mnt ||
3887             src->i_sb != inode->i_sb)
3888                 return -EXDEV;
3889 
3890         /* don't make the dst file partly checksummed */
3891         if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
3892             (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
3893                 return -EINVAL;
3894 
3895         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
3896                 return -EISDIR;
3897 
3898         if (!same_inode) {
3899                 btrfs_double_inode_lock(src, inode);
3900         } else {
3901                 inode_lock(src);
3902         }
3903 
3904         /* determine range to clone */
3905         ret = -EINVAL;
3906         if (off + len > src->i_size || off + len < off)
3907                 goto out_unlock;
3908         if (len == 0)
3909                 olen = len = src->i_size - off;
3910         /* if we extend to eof, continue to block boundary */
3911         if (off + len == src->i_size)
3912                 len = ALIGN(src->i_size, bs) - off;
3913 
3914         if (len == 0) {
3915                 ret = 0;
3916                 goto out_unlock;
3917         }
3918 
3919         /* verify the end result is block aligned */
3920         if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
3921             !IS_ALIGNED(destoff, bs))
3922                 goto out_unlock;
3923 
3924         /* verify if ranges are overlapped within the same file */
3925         if (same_inode) {
3926                 if (destoff + len > off && destoff < off + len)
3927                         goto out_unlock;
3928         }
3929 
3930         if (destoff > inode->i_size) {
3931                 ret = btrfs_cont_expand(inode, inode->i_size, destoff);
3932                 if (ret)
3933                         goto out_unlock;
3934         }
3935 
3936         /*
3937          * Lock the target range too. Right after we replace the file extent
3938          * items in the fs tree (which now point to the cloned data), we might
3939          * have a worker replace them with extent items relative to a write
3940          * operation that was issued before this clone operation (i.e. confront
3941          * with inode.c:btrfs_finish_ordered_io).
3942          */
3943         if (same_inode) {
3944                 u64 lock_start = min_t(u64, off, destoff);
3945                 u64 lock_len = max_t(u64, off, destoff) + len - lock_start;
3946 
3947                 ret = lock_extent_range(src, lock_start, lock_len, true);
3948         } else {
3949                 ret = btrfs_double_extent_lock(src, off, inode, destoff, len,
3950                                                true);
3951         }
3952         ASSERT(ret == 0);
3953         if (WARN_ON(ret)) {
3954                 /* ranges in the io trees already unlocked */
3955                 goto out_unlock;
3956         }
3957 
3958         ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
3959 
3960         if (same_inode) {
3961                 u64 lock_start = min_t(u64, off, destoff);
3962                 u64 lock_end = max_t(u64, off, destoff) + len - 1;
3963 
3964                 unlock_extent(&BTRFS_I(src)->io_tree, lock_start, lock_end);
3965         } else {
3966                 btrfs_double_extent_unlock(src, off, inode, destoff, len);
3967         }
3968         /*
3969          * Truncate page cache pages so that future reads will see the cloned
3970          * data immediately and not the previous data.
3971          */
3972         truncate_inode_pages_range(&inode->i_data,
3973                                 round_down(destoff, PAGE_SIZE),
3974                                 round_up(destoff + len, PAGE_SIZE) - 1);
3975 out_unlock:
3976         if (!same_inode)
3977                 btrfs_double_inode_unlock(src, inode);
3978         else
3979                 inode_unlock(src);
3980         return ret;
3981 }
3982 
3983 int btrfs_clone_file_range(struct file *src_file, loff_t off,
3984                 struct file *dst_file, loff_t destoff, u64 len)
3985 {
3986         return btrfs_clone_files(dst_file, src_file, off, len, destoff);
3987 }
3988 
3989 /*
3990  * there are many ways the trans_start and trans_end ioctls can lead
3991  * to deadlocks.  They should only be used by applications that
3992  * basically own the machine, and have a very in depth understanding
3993  * of all the possible deadlocks and enospc problems.
3994  */
3995 static long btrfs_ioctl_trans_start(struct file *file)
3996 {
3997         struct inode *inode = file_inode(file);
3998         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3999         struct btrfs_root *root = BTRFS_I(inode)->root;
4000         struct btrfs_trans_handle *trans;
4001         int ret;
4002 
4003         ret = -EPERM;
4004         if (!capable(CAP_SYS_ADMIN))
4005                 goto out;
4006 
4007         ret = -EINPROGRESS;
4008         if (file->private_data)
4009                 goto out;
4010 
4011         ret = -EROFS;
4012         if (btrfs_root_readonly(root))
4013                 goto out;
4014 
4015         ret = mnt_want_write_file(file);
4016         if (ret)
4017                 goto out;
4018 
4019         atomic_inc(&fs_info->open_ioctl_trans);
4020 
4021         ret = -ENOMEM;
4022         trans = btrfs_start_ioctl_transaction(root);
4023         if (IS_ERR(trans))
4024                 goto out_drop;
4025 
4026         file->private_data = trans;
4027         return 0;
4028 
4029 out_drop:
4030         atomic_dec(&fs_info->open_ioctl_trans);
4031         mnt_drop_write_file(file);
4032 out:
4033         return ret;
4034 }
4035 
4036 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
4037 {
4038         struct inode *inode = file_inode(file);
4039         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4040         struct btrfs_root *root = BTRFS_I(inode)->root;
4041         struct btrfs_root *new_root;
4042         struct btrfs_dir_item *di;
4043         struct btrfs_trans_handle *trans;
4044         struct btrfs_path *path;
4045         struct btrfs_key location;
4046         struct btrfs_disk_key disk_key;
4047         u64 objectid = 0;
4048         u64 dir_id;
4049         int ret;
4050 
4051         if (!capable(CAP_SYS_ADMIN))
4052                 return -EPERM;
4053 
4054         ret = mnt_want_write_file(file);
4055         if (ret)
4056                 return ret;
4057 
4058         if (copy_from_user(&objectid, argp, sizeof(objectid))) {
4059                 ret = -EFAULT;
4060                 goto out;
4061         }
4062 
4063         if (!objectid)
4064                 objectid = BTRFS_FS_TREE_OBJECTID;
4065 
4066         location.objectid = objectid;
4067         location.type = BTRFS_ROOT_ITEM_KEY;
4068         location.offset = (u64)-1;
4069 
4070         new_root = btrfs_read_fs_root_no_name(fs_info, &location);
4071         if (IS_ERR(new_root)) {
4072                 ret = PTR_ERR(new_root);
4073                 goto out;
4074         }
4075         if (!is_fstree(new_root->objectid)) {
4076                 ret = -ENOENT;
4077                 goto out;
4078         }
4079 
4080         path = btrfs_alloc_path();
4081         if (!path) {
4082                 ret = -ENOMEM;
4083                 goto out;
4084         }
4085         path->leave_spinning = 1;
4086 
4087         trans = btrfs_start_transaction(root, 1);
4088         if (IS_ERR(trans)) {
4089                 btrfs_free_path(path);
4090                 ret = PTR_ERR(trans);
4091                 goto out;
4092         }
4093 
4094         dir_id = btrfs_super_root_dir(fs_info->super_copy);
4095         di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
4096                                    dir_id, "default", 7, 1);
4097         if (IS_ERR_OR_NULL(di)) {
4098                 btrfs_free_path(path);
4099                 btrfs_end_transaction(trans);
4100                 btrfs_err(fs_info,
4101                           "Umm, you don't have the default diritem, this isn't going to work");
4102                 ret = -ENOENT;
4103                 goto out;
4104         }
4105 
4106         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
4107         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
4108         btrfs_mark_buffer_dirty(path->nodes[0]);
4109         btrfs_free_path(path);
4110 
4111         btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
4112         btrfs_end_transaction(trans);
4113 out:
4114         mnt_drop_write_file(file);
4115         return ret;
4116 }
4117 
4118 void btrfs_get_block_group_info(struct list_head *groups_list,
4119                                 struct btrfs_ioctl_space_info *space)
4120 {
4121         struct btrfs_block_group_cache *block_group;
4122 
4123         space->total_bytes = 0;
4124         space->used_bytes = 0;
4125         space->flags = 0;
4126         list_for_each_entry(block_group, groups_list, list) {
4127                 space->flags = block_group->flags;
4128                 space->total_bytes += block_group->key.offset;
4129                 space->used_bytes +=
4130                         btrfs_block_group_used(&block_group->item);
4131         }
4132 }
4133 
4134 static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info,
4135                                    void __user *arg)
4136 {
4137         struct btrfs_ioctl_space_args space_args;
4138         struct btrfs_ioctl_space_info space;
4139         struct btrfs_ioctl_space_info *dest;
4140         struct btrfs_ioctl_space_info *dest_orig;
4141         struct btrfs_ioctl_space_info __user *user_dest;
4142         struct btrfs_space_info *info;
4143         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
4144                        BTRFS_BLOCK_GROUP_SYSTEM,
4145                        BTRFS_BLOCK_GROUP_METADATA,
4146                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
4147         int num_types = 4;
4148         int alloc_size;
4149         int ret = 0;
4150         u64 slot_count = 0;
4151         int i, c;
4152 
4153         if (copy_from_user(&space_args,
4154                            (struct btrfs_ioctl_space_args __user *)arg,
4155                            sizeof(space_args)))
4156                 return -EFAULT;
4157 
4158         for (i = 0; i < num_types; i++) {
4159                 struct btrfs_space_info *tmp;
4160 
4161                 info = NULL;
4162                 rcu_read_lock();
4163                 list_for_each_entry_rcu(tmp, &fs_info->space_info,
4164                                         list) {
4165                         if (tmp->flags == types[i]) {
4166                                 info = tmp;
4167                                 break;
4168                         }
4169                 }
4170                 rcu_read_unlock();
4171 
4172                 if (!info)
4173                         continue;
4174 
4175                 down_read(&info->groups_sem);
4176                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4177                         if (!list_empty(&info->block_groups[c]))
4178                                 slot_count++;
4179                 }
4180                 up_read(&info->groups_sem);
4181         }
4182 
4183         /*
4184          * Global block reserve, exported as a space_info
4185          */
4186         slot_count++;
4187 
4188         /* space_slots == 0 means they are asking for a count */
4189         if (space_args.space_slots == 0) {
4190                 space_args.total_spaces = slot_count;
4191                 goto out;
4192         }
4193 
4194         slot_count = min_t(u64, space_args.space_slots, slot_count);
4195 
4196         alloc_size = sizeof(*dest) * slot_count;
4197 
4198         /* we generally have at most 6 or so space infos, one for each raid
4199          * level.  So, a whole page should be more than enough for everyone
4200          */
4201         if (alloc_size > PAGE_SIZE)
4202                 return -ENOMEM;
4203 
4204         space_args.total_spaces = 0;
4205         dest = kmalloc(alloc_size, GFP_KERNEL);
4206         if (!dest)
4207                 return -ENOMEM;
4208         dest_orig = dest;
4209 
4210         /* now we have a buffer to copy into */
4211         for (i = 0; i < num_types; i++) {
4212                 struct btrfs_space_info *tmp;
4213 
4214                 if (!slot_count)
4215                         break;
4216 
4217                 info = NULL;
4218                 rcu_read_lock();
4219                 list_for_each_entry_rcu(tmp, &fs_info->space_info,
4220                                         list) {
4221                         if (tmp->flags == types[i]) {
4222                                 info = tmp;
4223                                 break;
4224                         }
4225                 }
4226                 rcu_read_unlock();
4227 
4228                 if (!info)
4229                         continue;
4230                 down_read(&info->groups_sem);
4231                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4232                         if (!list_empty(&info->block_groups[c])) {
4233                                 btrfs_get_block_group_info(
4234                                         &info->block_groups[c], &space);
4235                                 memcpy(dest, &space, sizeof(space));
4236                                 dest++;
4237                                 space_args.total_spaces++;
4238                                 slot_count--;
4239                         }
4240                         if (!slot_count)
4241                                 break;
4242                 }
4243                 up_read(&info->groups_sem);
4244         }
4245 
4246         /*
4247          * Add global block reserve
4248          */
4249         if (slot_count) {
4250                 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4251 
4252                 spin_lock(&block_rsv->lock);
4253                 space.total_bytes = block_rsv->size;
4254                 space.used_bytes = block_rsv->size - block_rsv->reserved;
4255                 spin_unlock(&block_rsv->lock);
4256                 space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
4257                 memcpy(dest, &space, sizeof(space));
4258                 space_args.total_spaces++;
4259         }
4260 
4261         user_dest = (struct btrfs_ioctl_space_info __user *)
4262                 (arg + sizeof(struct btrfs_ioctl_space_args));
4263 
4264         if (copy_to_user(user_dest, dest_orig, alloc_size))
4265                 ret = -EFAULT;
4266 
4267         kfree(dest_orig);
4268 out:
4269         if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
4270                 ret = -EFAULT;
4271 
4272         return ret;
4273 }
4274 
4275 /*
4276  * there are many ways the trans_start and trans_end ioctls can lead
4277  * to deadlocks.  They should only be used by applications that
4278  * basically own the machine, and have a very in depth understanding
4279  * of all the possible deadlocks and enospc problems.
4280  */
4281 long btrfs_ioctl_trans_end(struct file *file)
4282 {
4283         struct inode *inode = file_inode(file);
4284         struct btrfs_root *root = BTRFS_I(inode)->root;
4285         struct btrfs_trans_handle *trans;
4286 
4287         trans = file->private_data;
4288         if (!trans)
4289                 return -EINVAL;
4290         file->private_data = NULL;
4291 
4292         btrfs_end_transaction(trans);
4293 
4294         atomic_dec(&root->fs_info->open_ioctl_trans);
4295 
4296         mnt_drop_write_file(file);
4297         return 0;
4298 }
4299 
4300 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
4301                                             void __user *argp)
4302 {
4303         struct btrfs_trans_handle *trans;
4304         u64 transid;
4305         int ret;
4306 
4307         trans = btrfs_attach_transaction_barrier(root);
4308         if (IS_ERR(trans)) {
4309                 if (PTR_ERR(trans) != -ENOENT)
4310                         return PTR_ERR(trans);
4311 
4312                 /* No running transaction, don't bother */
4313                 transid = root->fs_info->last_trans_committed;
4314                 goto out;
4315         }
4316         transid = trans->transid;
4317         ret = btrfs_commit_transaction_async(trans, 0);
4318         if (ret) {
4319                 btrfs_end_transaction(trans);
4320                 return ret;
4321         }
4322 out:
4323         if (argp)
4324                 if (copy_to_user(argp, &transid, sizeof(transid)))
4325                         return -EFAULT;
4326         return 0;
4327 }
4328 
4329 static noinline long btrfs_ioctl_wait_sync(struct btrfs_fs_info *fs_info,
4330                                            void __user *argp)
4331 {
4332         u64 transid;
4333 
4334         if (argp) {
4335                 if (copy_from_user(&transid, argp, sizeof(transid)))
4336                         return -EFAULT;
4337         } else {
4338                 transid = 0;  /* current trans */
4339         }
4340         return btrfs_wait_for_commit(fs_info, transid);
4341 }
4342 
4343 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
4344 {
4345         struct btrfs_fs_info *fs_info = btrfs_sb(file_inode(file)->i_sb);
4346         struct btrfs_ioctl_scrub_args *sa;
4347         int ret;
4348 
4349         if (!capable(CAP_SYS_ADMIN))
4350                 return -EPERM;
4351 
4352         sa = memdup_user(arg, sizeof(*sa));
4353         if (IS_ERR(sa))
4354                 return PTR_ERR(sa);
4355 
4356         if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
4357                 ret = mnt_want_write_file(file);
4358                 if (ret)
4359                         goto out;
4360         }
4361 
4362         ret = btrfs_scrub_dev(fs_info, sa->devid, sa->start, sa->end,
4363                               &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
4364                               0);
4365 
4366         if (copy_to_user(arg, sa, sizeof(*sa)))
4367                 ret = -EFAULT;
4368 
4369         if (!(sa->flags & BTRFS_SCRUB_READONLY))
4370                 mnt_drop_write_file(file);
4371 out:
4372         kfree(sa);
4373         return ret;
4374 }
4375 
4376 static long btrfs_ioctl_scrub_cancel(struct btrfs_fs_info *fs_info)
4377 {
4378         if (!capable(CAP_SYS_ADMIN))
4379                 return -EPERM;
4380 
4381         return btrfs_scrub_cancel(fs_info);
4382 }
4383 
4384 static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
4385                                        void __user *arg)
4386 {
4387         struct btrfs_ioctl_scrub_args *sa;
4388         int ret;
4389 
4390         if (!capable(CAP_SYS_ADMIN))
4391                 return -EPERM;
4392 
4393         sa = memdup_user(arg, sizeof(*sa));
4394         if (IS_ERR(sa))
4395                 return PTR_ERR(sa);
4396 
4397         ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
4398 
4399         if (copy_to_user(arg, sa, sizeof(*sa)))
4400                 ret = -EFAULT;
4401 
4402         kfree(sa);
4403         return ret;
4404 }
4405 
4406 static long btrfs_ioctl_get_dev_stats(struct btrfs_fs_info *fs_info,
4407                                       void __user *arg)
4408 {
4409         struct btrfs_ioctl_get_dev_stats *sa;
4410         int ret;
4411 
4412         sa = memdup_user(arg, sizeof(*sa));
4413         if (IS_ERR(sa))
4414                 return PTR_ERR(sa);
4415 
4416         if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
4417                 kfree(sa);
4418                 return -EPERM;
4419         }
4420 
4421         ret = btrfs_get_dev_stats(fs_info, sa);
4422 
4423         if (copy_to_user(arg, sa, sizeof(*sa)))
4424                 ret = -EFAULT;
4425 
4426         kfree(sa);
4427         return ret;
4428 }
4429 
4430 static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
4431                                     void __user *arg)
4432 {
4433         struct btrfs_ioctl_dev_replace_args *p;
4434         int ret;
4435 
4436         if (!capable(CAP_SYS_ADMIN))
4437                 return -EPERM;
4438 
4439         p = memdup_user(arg, sizeof(*p));
4440         if (IS_ERR(p))
4441                 return PTR_ERR(p);
4442 
4443         switch (p->cmd) {
4444         case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
4445                 if (fs_info->sb->s_flags & MS_RDONLY) {
4446                         ret = -EROFS;
4447                         goto out;
4448                 }
4449                 if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
4450                         ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4451                 } else {
4452                         ret = btrfs_dev_replace_by_ioctl(fs_info, p);
4453                         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
4454                 }
4455                 break;
4456         case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
4457                 btrfs_dev_replace_status(fs_info, p);
4458                 ret = 0;
4459                 break;
4460         case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
4461                 ret = btrfs_dev_replace_cancel(fs_info, p);
4462                 break;
4463         default:
4464                 ret = -EINVAL;
4465                 break;
4466         }
4467 
4468         if (copy_to_user(arg, p, sizeof(*p)))
4469                 ret = -EFAULT;
4470 out:
4471         kfree(p);
4472         return ret;
4473 }
4474 
4475 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
4476 {
4477         int ret = 0;
4478         int i;
4479         u64 rel_ptr;
4480         int size;
4481         struct btrfs_ioctl_ino_path_args *ipa = NULL;
4482         struct inode_fs_paths *ipath = NULL;
4483         struct btrfs_path *path;
4484 
4485         if (!capable(CAP_DAC_READ_SEARCH))
4486                 return -EPERM;
4487 
4488         path = btrfs_alloc_path();
4489         if (!path) {
4490                 ret = -ENOMEM;
4491                 goto out;
4492         }
4493 
4494         ipa = memdup_user(arg, sizeof(*ipa));
4495         if (IS_ERR(ipa)) {
4496                 ret = PTR_ERR(ipa);
4497                 ipa = NULL;
4498                 goto out;
4499         }
4500 
4501         size = min_t(u32, ipa->size, 4096);
4502         ipath = init_ipath(size, root, path);
4503         if (IS_ERR(ipath)) {
4504                 ret = PTR_ERR(ipath);
4505                 ipath = NULL;
4506                 goto out;
4507         }
4508 
4509         ret = paths_from_inode(ipa->inum, ipath);
4510         if (ret < 0)
4511                 goto out;
4512 
4513         for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
4514                 rel_ptr = ipath->fspath->val[i] -
4515                           (u64)(unsigned long)ipath->fspath->val;
4516                 ipath->fspath->val[i] = rel_ptr;
4517         }
4518 
4519         ret = copy_to_user((void *)(unsigned long)ipa->fspath,
4520                            (void *)(unsigned long)ipath->fspath, size);
4521         if (ret) {
4522                 ret = -EFAULT;
4523                 goto out;
4524         }
4525 
4526 out:
4527         btrfs_free_path(path);
4528         free_ipath(ipath);
4529         kfree(ipa);
4530 
4531         return ret;
4532 }
4533 
4534 static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
4535 {
4536         struct btrfs_data_container *inodes = ctx;
4537         const size_t c = 3 * sizeof(u64);
4538 
4539         if (inodes->bytes_left >= c) {
4540                 inodes->bytes_left -= c;
4541                 inodes->val[inodes->elem_cnt] = inum;
4542                 inodes->val[inodes->elem_cnt + 1] = offset;
4543                 inodes->val[inodes->elem_cnt + 2] = root;
4544                 inodes->elem_cnt += 3;
4545         } else {
4546                 inodes->bytes_missing += c - inodes->bytes_left;
4547                 inodes->bytes_left = 0;
4548                 inodes->elem_missed += 3;
4549         }
4550 
4551         return 0;
4552 }
4553 
4554 static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
4555                                         void __user *arg)
4556 {
4557         int ret = 0;
4558         int size;
4559         struct btrfs_ioctl_logical_ino_args *loi;
4560         struct btrfs_data_container *inodes = NULL;
4561         struct btrfs_path *path = NULL;
4562 
4563         if (!capable(CAP_SYS_ADMIN))
4564                 return -EPERM;
4565 
4566         loi = memdup_user(arg, sizeof(*loi));
4567         if (IS_ERR(loi))
4568                 return PTR_ERR(loi);
4569 
4570         path = btrfs_alloc_path();
4571         if (!path) {
4572                 ret = -ENOMEM;
4573                 goto out;
4574         }
4575 
4576         size = min_t(u32, loi->size, SZ_64K);
4577         inodes = init_data_container(size);
4578         if (IS_ERR(inodes)) {
4579                 ret = PTR_ERR(inodes);
4580                 inodes = NULL;
4581                 goto out;
4582         }
4583 
4584         ret = iterate_inodes_from_logical(loi->logical, fs_info, path,
4585                                           build_ino_list, inodes);
4586         if (ret == -EINVAL)
4587                 ret = -ENOENT;
4588         if (ret < 0)
4589                 goto out;
4590 
4591         ret = copy_to_user((void *)(unsigned long)loi->inodes,
4592                            (void *)(unsigned long)inodes, size);
4593         if (ret)
4594                 ret = -EFAULT;
4595 
4596 out:
4597         btrfs_free_path(path);
4598         kvfree(inodes);
4599         kfree(loi);
4600 
4601         return ret;
4602 }
4603 
4604 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
4605                                struct btrfs_ioctl_balance_args *bargs)
4606 {
4607         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4608 
4609         bargs->flags = bctl->flags;
4610 
4611         if (atomic_read(&fs_info->balance_running))
4612                 bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
4613         if (atomic_read(&fs_info->balance_pause_req))
4614                 bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
4615         if (atomic_read(&fs_info->balance_cancel_req))
4616                 bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
4617 
4618         memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
4619         memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
4620         memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
4621 
4622         if (lock) {
4623                 spin_lock(&fs_info->balance_lock);
4624                 memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4625                 spin_unlock(&fs_info->balance_lock);
4626         } else {
4627                 memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4628         }
4629 }
4630 
4631 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
4632 {
4633         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4634         struct btrfs_fs_info *fs_info = root->fs_info;
4635         struct btrfs_ioctl_balance_args *bargs;
4636         struct btrfs_balance_control *bctl;
4637         bool need_unlock; /* for mut. excl. ops lock */
4638         int ret;
4639 
4640         if (!capable(CAP_SYS_ADMIN))
4641                 return -EPERM;
4642 
4643         ret = mnt_want_write_file(file);
4644         if (ret)
4645                 return ret;
4646 
4647 again:
4648         if (!test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
4649                 mutex_lock(&fs_info->volume_mutex);
4650                 mutex_lock(&fs_info->balance_mutex);
4651                 need_unlock = true;
4652                 goto locked;
4653         }
4654 
4655         /*
4656          * mut. excl. ops lock is locked.  Three possibilities:
4657          *   (1) some other op is running
4658          *   (2) balance is running
4659          *   (3) balance is paused -- special case (think resume)
4660          */
4661         mutex_lock(&fs_info->balance_mutex);
4662         if (fs_info->balance_ctl) {
4663                 /* this is either (2) or (3) */
4664                 if (!atomic_read(&fs_info->balance_running)) {
4665                         mutex_unlock(&fs_info->balance_mutex);
4666                         if (!mutex_trylock(&fs_info->volume_mutex))
4667                                 goto again;
4668                         mutex_lock(&fs_info->balance_mutex);
4669 
4670                         if (fs_info->balance_ctl &&
4671                             !atomic_read(&fs_info->balance_running)) {
4672                                 /* this is (3) */
4673                                 need_unlock = false;
4674                                 goto locked;
4675                         }
4676 
4677                         mutex_unlock(&fs_info->balance_mutex);
4678                         mutex_unlock(&fs_info->volume_mutex);
4679                         goto again;
4680                 } else {
4681                         /* this is (2) */
4682                         mutex_unlock(&fs_info->balance_mutex);
4683                         ret = -EINPROGRESS;
4684                         goto out;
4685                 }
4686         } else {
4687                 /* this is (1) */
4688                 mutex_unlock(&fs_info->balance_mutex);
4689                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4690                 goto out;
4691         }
4692 
4693 locked:
4694         BUG_ON(!test_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
4695 
4696         if (arg) {
4697                 bargs = memdup_user(arg, sizeof(*bargs));
4698                 if (IS_ERR(bargs)) {
4699                         ret = PTR_ERR(bargs);
4700                         goto out_unlock;
4701                 }
4702 
4703                 if (bargs->flags & BTRFS_BALANCE_RESUME) {
4704                         if (!fs_info->balance_ctl) {
4705                                 ret = -ENOTCONN;
4706                                 goto out_bargs;
4707                         }
4708 
4709                         bctl = fs_info->balance_ctl;
4710                         spin_lock(&fs_info->balance_lock);
4711                         bctl->flags |= BTRFS_BALANCE_RESUME;
4712                         spin_unlock(&fs_info->balance_lock);
4713 
4714                         goto do_balance;
4715                 }
4716         } else {
4717                 bargs = NULL;
4718         }
4719 
4720         if (fs_info->balance_ctl) {
4721                 ret = -EINPROGRESS;
4722                 goto out_bargs;
4723         }
4724 
4725         bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
4726         if (!bctl) {
4727                 ret = -ENOMEM;
4728                 goto out_bargs;
4729         }
4730 
4731         bctl->fs_info = fs_info;
4732         if (arg) {
4733                 memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
4734                 memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
4735                 memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
4736 
4737                 bctl->flags = bargs->flags;
4738         } else {
4739                 /* balance everything - no filters */
4740                 bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
4741         }
4742 
4743         if (bctl->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
4744                 ret = -EINVAL;
4745                 goto out_bctl;
4746         }
4747 
4748 do_balance:
4749         /*
4750          * Ownership of bctl and filesystem flag BTRFS_FS_EXCL_OP
4751          * goes to to btrfs_balance.  bctl is freed in __cancel_balance,
4752          * or, if restriper was paused all the way until unmount, in
4753          * free_fs_info.  The flag is cleared in __cancel_balance.
4754          */
4755         need_unlock = false;
4756 
4757         ret = btrfs_balance(bctl, bargs);
4758         bctl = NULL;
4759 
4760         if (arg) {
4761                 if (copy_to_user(arg, bargs, sizeof(*bargs)))
4762                         ret = -EFAULT;
4763         }
4764 
4765 out_bctl:
4766         kfree(bctl);
4767 out_bargs:
4768         kfree(bargs);
4769 out_unlock:
4770         mutex_unlock(&fs_info->balance_mutex);
4771         mutex_unlock(&fs_info->volume_mutex);
4772         if (need_unlock)
4773                 clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
4774 out:
4775         mnt_drop_write_file(file);
4776         return ret;
4777 }
4778 
4779 static long btrfs_ioctl_balance_ctl(struct btrfs_fs_info *fs_info, int cmd)
4780 {
4781         if (!capable(CAP_SYS_ADMIN))
4782                 return -EPERM;
4783 
4784         switch (cmd) {
4785         case BTRFS_BALANCE_CTL_PAUSE:
4786                 return btrfs_pause_balance(fs_info);
4787         case BTRFS_BALANCE_CTL_CANCEL:
4788                 return btrfs_cancel_balance(fs_info);
4789         }
4790 
4791         return -EINVAL;
4792 }
4793 
4794 static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
4795                                          void __user *arg)
4796 {
4797         struct btrfs_ioctl_balance_args *bargs;
4798         int ret = 0;
4799 
4800         if (!capable(CAP_SYS_ADMIN))
4801                 return -EPERM;
4802 
4803         mutex_lock(&fs_info->balance_mutex);
4804         if (!fs_info->balance_ctl) {
4805                 ret = -ENOTCONN;
4806                 goto out;
4807         }
4808 
4809         bargs = kzalloc(sizeof(*bargs), GFP_KERNEL);
4810         if (!bargs) {
4811                 ret = -ENOMEM;
4812                 goto out;
4813         }
4814 
4815         update_ioctl_balance_args(fs_info, 1, bargs);
4816 
4817         if (copy_to_user(arg, bargs, sizeof(*bargs)))
4818                 ret = -EFAULT;
4819 
4820         kfree(bargs);
4821 out:
4822         mutex_unlock(&fs_info->balance_mutex);
4823         return ret;
4824 }
4825 
4826 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
4827 {
4828         struct inode *inode = file_inode(file);
4829         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4830         struct btrfs_ioctl_quota_ctl_args *sa;
4831         struct btrfs_trans_handle *trans = NULL;
4832         int ret;
4833         int err;
4834 
4835         if (!capable(CAP_SYS_ADMIN))
4836                 return -EPERM;
4837 
4838         ret = mnt_want_write_file(file);
4839         if (ret)
4840                 return ret;
4841 
4842         sa = memdup_user(arg, sizeof(*sa));
4843         if (IS_ERR(sa)) {
4844                 ret = PTR_ERR(sa);
4845                 goto drop_write;
4846         }
4847 
4848         down_write(&fs_info->subvol_sem);
4849         trans = btrfs_start_transaction(fs_info->tree_root, 2);
4850         if (IS_ERR(trans)) {
4851                 ret = PTR_ERR(trans);
4852                 goto out;
4853         }
4854 
4855         switch (sa->cmd) {
4856         case BTRFS_QUOTA_CTL_ENABLE:
4857                 ret = btrfs_quota_enable(trans, fs_info);
4858                 break;
4859         case BTRFS_QUOTA_CTL_DISABLE:
4860                 ret = btrfs_quota_disable(trans, fs_info);
4861                 break;
4862         default:
4863                 ret = -EINVAL;
4864                 break;
4865         }
4866 
4867         err = btrfs_commit_transaction(trans);
4868         if (err && !ret)
4869                 ret = err;
4870 out:
4871         kfree(sa);
4872         up_write(&fs_info->subvol_sem);
4873 drop_write:
4874         mnt_drop_write_file(file);
4875         return ret;
4876 }
4877 
4878 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
4879 {
4880         struct inode *inode = file_inode(file);
4881         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4882         struct btrfs_root *root = BTRFS_I(inode)->root;
4883         struct btrfs_ioctl_qgroup_assign_args *sa;
4884         struct btrfs_trans_handle *trans;
4885         int ret;
4886         int err;
4887 
4888         if (!capable(CAP_SYS_ADMIN))
4889                 return -EPERM;
4890 
4891         ret = mnt_want_write_file(file);
4892         if (ret)
4893                 return ret;
4894 
4895         sa = memdup_user(arg, sizeof(*sa));
4896         if (IS_ERR(sa)) {
4897                 ret = PTR_ERR(sa);
4898                 goto drop_write;
4899         }
4900 
4901         trans = btrfs_join_transaction(root);
4902         if (IS_ERR(trans)) {
4903                 ret = PTR_ERR(trans);
4904                 goto out;
4905         }
4906 
4907         if (sa->assign) {
4908                 ret = btrfs_add_qgroup_relation(trans, fs_info,
4909                                                 sa->src, sa->dst);
4910         } else {
4911                 ret = btrfs_del_qgroup_relation(trans, fs_info,
4912                                                 sa->src, sa->dst);
4913         }
4914 
4915         /* update qgroup status and info */
4916         err = btrfs_run_qgroups(trans, fs_info);
4917         if (err < 0)
4918                 btrfs_handle_fs_error(fs_info, err,
4919                                       "failed to update qgroup status and info");
4920         err = btrfs_end_transaction(trans);
4921         if (err && !ret)
4922                 ret = err;
4923 
4924 out:
4925         kfree(sa);
4926 drop_write:
4927         mnt_drop_write_file(file);
4928         return ret;
4929 }
4930 
4931 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
4932 {
4933         struct inode *inode = file_inode(file);
4934         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4935         struct btrfs_root *root = BTRFS_I(inode)->root;
4936         struct btrfs_ioctl_qgroup_create_args *sa;
4937         struct btrfs_trans_handle *trans;
4938         int ret;
4939         int err;
4940 
4941         if (!capable(CAP_SYS_ADMIN))
4942                 return -EPERM;
4943 
4944         ret = mnt_want_write_file(file);
4945         if (ret)
4946                 return ret;
4947 
4948         sa = memdup_user(arg, sizeof(*sa));
4949         if (IS_ERR(sa)) {
4950                 ret = PTR_ERR(sa);
4951                 goto drop_write;
4952         }
4953 
4954         if (!sa->qgroupid) {
4955                 ret = -EINVAL;
4956                 goto out;
4957         }
4958 
4959         trans = btrfs_join_transaction(root);
4960         if (IS_ERR(trans)) {
4961                 ret = PTR_ERR(trans);
4962                 goto out;
4963         }
4964 
4965         if (sa->create) {
4966                 ret = btrfs_create_qgroup(trans, fs_info, sa->qgroupid);
4967         } else {
4968                 ret = btrfs_remove_qgroup(trans, fs_info, sa->qgroupid);
4969         }
4970 
4971         err = btrfs_end_transaction(trans);
4972         if (err && !ret)
4973                 ret = err;
4974 
4975 out:
4976         kfree(sa);
4977 drop_write:
4978         mnt_drop_write_file(file);
4979         return ret;
4980 }
4981 
4982 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
4983 {
4984         struct inode *inode = file_inode(file);
4985         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4986         struct btrfs_root *root = BTRFS_I(inode)->root;
4987         struct btrfs_ioctl_qgroup_limit_args *sa;
4988         struct btrfs_trans_handle *trans;
4989         int ret;
4990         int err;
4991         u64 qgroupid;
4992 
4993         if (!capable(CAP_SYS_ADMIN))
4994                 return -EPERM;
4995 
4996         ret = mnt_want_write_file(file);
4997         if (ret)
4998                 return ret;
4999 
5000         sa = memdup_user(arg, sizeof(*sa));
5001         if (IS_ERR(sa)) {
5002                 ret = PTR_ERR(sa);
5003                 goto drop_write;
5004         }
5005 
5006         trans = btrfs_join_transaction(root);
5007         if (IS_ERR(trans)) {
5008                 ret = PTR_ERR(trans);
5009                 goto out;
5010         }
5011 
5012         qgroupid = sa->qgroupid;
5013         if (!qgroupid) {
5014                 /* take the current subvol as qgroup */
5015                 qgroupid = root->root_key.objectid;
5016         }
5017 
5018         ret = btrfs_limit_qgroup(trans, fs_info, qgroupid, &sa->lim);
5019 
5020         err = btrfs_end_transaction(trans);
5021         if (err && !ret)
5022                 ret = err;
5023 
5024 out:
5025         kfree(sa);
5026 drop_write:
5027         mnt_drop_write_file(file);
5028         return ret;
5029 }
5030 
5031 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
5032 {
5033         struct inode *inode = file_inode(file);
5034         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5035         struct btrfs_ioctl_quota_rescan_args *qsa;
5036         int ret;
5037 
5038         if (!capable(CAP_SYS_ADMIN))
5039                 return -EPERM;
5040 
5041         ret = mnt_want_write_file(file);
5042         if (ret)
5043                 return ret;
5044 
5045         qsa = memdup_user(arg, sizeof(*qsa));
5046         if (IS_ERR(qsa)) {
5047                 ret = PTR_ERR(qsa);
5048                 goto drop_write;
5049         }
5050 
5051         if (qsa->flags) {
5052                 ret = -EINVAL;
5053                 goto out;
5054         }
5055 
5056         ret = btrfs_qgroup_rescan(fs_info);
5057 
5058 out:
5059         kfree(qsa);
5060 drop_write:
5061         mnt_drop_write_file(file);
5062         return ret;
5063 }
5064 
5065 static long btrfs_ioctl_quota_rescan_status(struct file *file, void __user *arg)
5066 {
5067         struct inode *inode = file_inode(file);
5068         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5069         struct btrfs_ioctl_quota_rescan_args *qsa;
5070         int ret = 0;
5071 
5072         if (!capable(CAP_SYS_ADMIN))
5073                 return -EPERM;
5074 
5075         qsa = kzalloc(sizeof(*qsa), GFP_KERNEL);
5076         if (!qsa)
5077                 return -ENOMEM;
5078 
5079         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
5080                 qsa->flags = 1;
5081                 qsa->progress = fs_info->qgroup_rescan_progress.objectid;
5082         }
5083 
5084         if (copy_to_user(arg, qsa, sizeof(*qsa)))
5085                 ret = -EFAULT;
5086 
5087         kfree(qsa);
5088         return ret;
5089 }
5090 
5091 static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg)
5092 {
5093         struct inode *inode = file_inode(file);
5094         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5095 
5096         if (!capable(CAP_SYS_ADMIN))
5097                 return -EPERM;
5098 
5099         return btrfs_qgroup_wait_for_completion(fs_info, true);
5100 }
5101 
5102 static long _btrfs_ioctl_set_received_subvol(struct file *file,
5103                                             struct btrfs_ioctl_received_subvol_args *sa)
5104 {
5105         struct inode *inode = file_inode(file);
5106         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5107         struct btrfs_root *root = BTRFS_I(inode)->root;
5108         struct btrfs_root_item *root_item = &root->root_item;
5109         struct btrfs_trans_handle *trans;
5110         struct timespec ct = current_time(inode);
5111         int ret = 0;
5112         int received_uuid_changed;
5113 
5114         if (!inode_owner_or_capable(inode))
5115                 return -EPERM;
5116 
5117         ret = mnt_want_write_file(file);
5118         if (ret < 0)
5119                 return ret;
5120 
5121         down_write(&fs_info->subvol_sem);
5122 
5123         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
5124                 ret = -EINVAL;
5125                 goto out;
5126         }
5127 
5128         if (btrfs_root_readonly(root)) {
5129                 ret = -EROFS;
5130                 goto out;
5131         }
5132 
5133         /*
5134          * 1 - root item
5135          * 2 - uuid items (received uuid + subvol uuid)
5136          */
5137         trans = btrfs_start_transaction(root, 3);
5138         if (IS_ERR(trans)) {
5139                 ret = PTR_ERR(trans);
5140                 trans = NULL;
5141                 goto out;
5142         }
5143 
5144         sa->rtransid = trans->transid;
5145         sa->rtime.sec = ct.tv_sec;
5146         sa->rtime.nsec = ct.tv_nsec;
5147 
5148         received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
5149                                        BTRFS_UUID_SIZE);
5150         if (received_uuid_changed &&
5151             !btrfs_is_empty_uuid(root_item->received_uuid))
5152                 btrfs_uuid_tree_rem(trans, fs_info, root_item->received_uuid,
5153                                     BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5154                                     root->root_key.objectid);
5155         memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
5156         btrfs_set_root_stransid(root_item, sa->stransid);
5157         btrfs_set_root_rtransid(root_item, sa->rtransid);
5158         btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
5159         btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
5160         btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
5161         btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
5162 
5163         ret = btrfs_update_root(trans, fs_info->tree_root,
5164                                 &root->root_key, &root->root_item);
5165         if (ret < 0) {
5166                 btrfs_end_transaction(trans);
5167                 goto out;
5168         }
5169         if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
5170                 ret = btrfs_uuid_tree_add(trans, fs_info, sa->uuid,
5171                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5172                                           root->root_key.objectid);
5173                 if (ret < 0 && ret != -EEXIST) {
5174                         btrfs_abort_transaction(trans, ret);
5175                         goto out;
5176                 }
5177         }
5178         ret = btrfs_commit_transaction(trans);
5179         if (ret < 0) {
5180                 btrfs_abort_transaction(trans, ret);
5181                 goto out;
5182         }
5183 
5184 out:
5185         up_write(&fs_info->subvol_sem);
5186         mnt_drop_write_file(file);
5187         return ret;
5188 }
5189 
5190 #ifdef CONFIG_64BIT
5191 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
5192                                                 void __user *arg)
5193 {
5194         struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
5195         struct btrfs_ioctl_received_subvol_args *args64 = NULL;
5196         int ret = 0;
5197 
5198         args32 = memdup_user(arg, sizeof(*args32));
5199         if (IS_ERR(args32))
5200                 return PTR_ERR(args32);
5201 
5202         args64 = kmalloc(sizeof(*args64), GFP_KERNEL);
5203         if (!args64) {
5204                 ret = -ENOMEM;
5205                 goto out;
5206         }
5207 
5208         memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
5209         args64->stransid = args32->stransid;
5210         args64->rtransid = args32->rtransid;
5211         args64->stime.sec = args32->stime.sec;
5212         args64->stime.nsec = args32->stime.nsec;
5213         args64->rtime.sec = args32->rtime.sec;
5214         args64->rtime.nsec = args32->rtime.nsec;
5215         args64->flags = args32->flags;
5216 
5217         ret = _btrfs_ioctl_set_received_subvol(file, args64);
5218         if (ret)
5219                 goto out;
5220 
5221         memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
5222         args32->stransid = args64->stransid;
5223         args32->rtransid = args64->rtransid;
5224         args32->stime.sec = args64->stime.sec;
5225         args32->stime.nsec = args64->stime.nsec;
5226         args32->rtime.sec = args64->rtime.sec;
5227         args32->rtime.nsec = args64->rtime.nsec;
5228         args32->flags = args64->flags;
5229 
5230         ret = copy_to_user(arg, args32, sizeof(*args32));
5231         if (ret)
5232                 ret = -EFAULT;
5233 
5234 out:
5235         kfree(args32);
5236         kfree(args64);
5237         return ret;
5238 }
5239 #endif
5240 
5241 static long btrfs_ioctl_set_received_subvol(struct file *file,
5242                                             void __user *arg)
5243 {
5244         struct btrfs_ioctl_received_subvol_args *sa = NULL;
5245         int ret = 0;
5246 
5247         sa = memdup_user(arg, sizeof(*sa));
5248         if (IS_ERR(sa))
5249                 return PTR_ERR(sa);
5250 
5251         ret = _btrfs_ioctl_set_received_subvol(file, sa);
5252 
5253         if (ret)
5254                 goto out;
5255 
5256         ret = copy_to_user(arg, sa, sizeof(*sa));
5257         if (ret)
5258                 ret = -EFAULT;
5259 
5260 out:
5261         kfree(sa);
5262         return ret;
5263 }
5264 
5265 static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
5266 {
5267         struct inode *inode = file_inode(file);
5268         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5269         size_t len;
5270         int ret;
5271         char label[BTRFS_LABEL_SIZE];
5272 
5273         spin_lock(&fs_info->super_lock);
5274         memcpy(label, fs_info->super_copy->label, BTRFS_LABEL_SIZE);
5275         spin_unlock(&fs_info->super_lock);
5276 
5277         len = strnlen(label, BTRFS_LABEL_SIZE);
5278 
5279         if (len == BTRFS_LABEL_SIZE) {
5280                 btrfs_warn(fs_info,
5281                            "label is too long, return the first %zu bytes",
5282                            --len);
5283         }
5284 
5285         ret = copy_to_user(arg, label, len);
5286 
5287         return ret ? -EFAULT : 0;
5288 }
5289 
5290 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
5291 {
5292         struct inode *inode = file_inode(file);
5293         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5294         struct btrfs_root *root = BTRFS_I(inode)->root;
5295         struct btrfs_super_block *super_block = fs_info->super_copy;
5296         struct btrfs_trans_handle *trans;
5297         char label[BTRFS_LABEL_SIZE];
5298         int ret;
5299 
5300         if (!capable(CAP_SYS_ADMIN))
5301                 return -EPERM;
5302 
5303         if (copy_from_user(label, arg, sizeof(label)))
5304                 return -EFAULT;
5305 
5306         if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
5307                 btrfs_err(fs_info,
5308                           "unable to set label with more than %d bytes",
5309                           BTRFS_LABEL_SIZE - 1);
5310                 return -EINVAL;
5311         }
5312 
5313         ret = mnt_want_write_file(file);
5314         if (ret)
5315                 return ret;
5316 
5317         trans = btrfs_start_transaction(root, 0);
5318         if (IS_ERR(trans)) {
5319                 ret = PTR_ERR(trans);
5320                 goto out_unlock;
5321         }
5322 
5323         spin_lock(&fs_info->super_lock);
5324         strcpy(super_block->label, label);
5325         spin_unlock(&fs_info->super_lock);
5326         ret = btrfs_commit_transaction(trans);
5327 
5328 out_unlock:
5329         mnt_drop_write_file(file);
5330         return ret;
5331 }
5332 
5333 #define INIT_FEATURE_FLAGS(suffix) \
5334         { .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
5335           .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
5336           .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
5337 
5338 int btrfs_ioctl_get_supported_features(void __user *arg)
5339 {
5340         static const struct btrfs_ioctl_feature_flags features[3] = {
5341                 INIT_FEATURE_FLAGS(SUPP),
5342                 INIT_FEATURE_FLAGS(SAFE_SET),
5343                 INIT_FEATURE_FLAGS(SAFE_CLEAR)
5344         };
5345 
5346         if (copy_to_user(arg, &features, sizeof(features)))
5347                 return -EFAULT;
5348 
5349         return 0;
5350 }
5351 
5352 static int btrfs_ioctl_get_features(struct file *file, void __user *arg)
5353 {
5354         struct inode *inode = file_inode(file);
5355         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5356         struct btrfs_super_block *super_block = fs_info->super_copy;
5357         struct btrfs_ioctl_feature_flags features;
5358 
5359         features.compat_flags = btrfs_super_compat_flags(super_block);
5360         features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
5361         features.incompat_flags = btrfs_super_incompat_flags(super_block);
5362 
5363         if (copy_to_user(arg, &features, sizeof(features)))
5364                 return -EFAULT;
5365 
5366         return 0;
5367 }
5368 
5369 static int check_feature_bits(struct btrfs_fs_info *fs_info,
5370                               enum btrfs_feature_set set,
5371                               u64 change_mask, u64 flags, u64 supported_flags,
5372                               u64 safe_set, u64 safe_clear)
5373 {
5374         const char *type = btrfs_feature_set_names[set];
5375         char *names;
5376         u64 disallowed, unsupported;
5377         u64 set_mask = flags & change_mask;
5378         u64 clear_mask = ~flags & change_mask;
5379 
5380         unsupported = set_mask & ~supported_flags;
5381         if (unsupported) {
5382                 names = btrfs_printable_features(set, unsupported);
5383                 if (names) {
5384                         btrfs_warn(fs_info,
5385                                    "this kernel does not support the %s feature bit%s",
5386                                    names, strchr(names, ',') ? "s" : "");
5387                         kfree(names);
5388                 } else
5389                         btrfs_warn(fs_info,
5390                                    "this kernel does not support %s bits 0x%llx",
5391                                    type, unsupported);
5392                 return -EOPNOTSUPP;
5393         }
5394 
5395         disallowed = set_mask & ~safe_set;
5396         if (disallowed) {
5397                 names = btrfs_printable_features(set, disallowed);
5398                 if (names) {
5399                         btrfs_warn(fs_info,
5400                                    "can't set the %s feature bit%s while mounted",
5401                                    names, strchr(names, ',') ? "s" : "");
5402                         kfree(names);
5403                 } else
5404                         btrfs_warn(fs_info,
5405                                    "can't set %s bits 0x%llx while mounted",
5406                                    type, disallowed);
5407                 return -EPERM;
5408         }
5409 
5410         disallowed = clear_mask & ~safe_clear;
5411         if (disallowed) {
5412                 names = btrfs_printable_features(set, disallowed);
5413                 if (names) {
5414                         btrfs_warn(fs_info,
5415                                    "can't clear the %s feature bit%s while mounted",
5416                                    names, strchr(names, ',') ? "s" : "");
5417                         kfree(names);
5418                 } else
5419                         btrfs_warn(fs_info,
5420                                    "can't clear %s bits 0x%llx while mounted",
5421                                    type, disallowed);
5422                 return -EPERM;
5423         }
5424 
5425         return 0;
5426 }
5427 
5428 #define check_feature(fs_info, change_mask, flags, mask_base)   \
5429 check_feature_bits(fs_info, FEAT_##mask_base, change_mask, flags,       \
5430                    BTRFS_FEATURE_ ## mask_base ## _SUPP,        \
5431                    BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,    \
5432                    BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
5433 
5434 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
5435 {
5436         struct inode *inode = file_inode(file);
5437         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5438         struct btrfs_root *root = BTRFS_I(inode)->root;
5439         struct btrfs_super_block *super_block = fs_info->super_copy;
5440         struct btrfs_ioctl_feature_flags flags[2];
5441         struct btrfs_trans_handle *trans;
5442         u64 newflags;
5443         int ret;
5444 
5445         if (!capable(CAP_SYS_ADMIN))
5446                 return -EPERM;
5447 
5448         if (copy_from_user(flags, arg, sizeof(flags)))
5449                 return -EFAULT;
5450 
5451         /* Nothing to do */
5452         if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
5453             !flags[0].incompat_flags)
5454                 return 0;
5455 
5456         ret = check_feature(fs_info, flags[0].compat_flags,
5457                             flags[1].compat_flags, COMPAT);
5458         if (ret)
5459                 return ret;
5460 
5461         ret = check_feature(fs_info, flags[0].compat_ro_flags,
5462                             flags[1].compat_ro_flags, COMPAT_RO);
5463         if (ret)
5464                 return ret;
5465 
5466         ret = check_feature(fs_info, flags[0].incompat_flags,
5467                             flags[1].incompat_flags, INCOMPAT);
5468         if (ret)
5469                 return ret;
5470 
5471         ret = mnt_want_write_file(file);
5472         if (ret)
5473                 return ret;
5474 
5475         trans = btrfs_start_transaction(root, 0);
5476         if (IS_ERR(trans)) {
5477                 ret = PTR_ERR(trans);
5478                 goto out_drop_write;
5479         }
5480 
5481         spin_lock(&fs_info->super_lock);
5482         newflags = btrfs_super_compat_flags(super_block);
5483         newflags |= flags[0].compat_flags & flags[1].compat_flags;
5484         newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
5485         btrfs_set_super_compat_flags(super_block, newflags);
5486 
5487         newflags = btrfs_super_compat_ro_flags(super_block);
5488         newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
5489         newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
5490         btrfs_set_super_compat_ro_flags(super_block, newflags);
5491 
5492         newflags = btrfs_super_incompat_flags(super_block);
5493         newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
5494         newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
5495         btrfs_set_super_incompat_flags(super_block, newflags);
5496         spin_unlock(&fs_info->super_lock);
5497 
5498         ret = btrfs_commit_transaction(trans);
5499 out_drop_write:
5500         mnt_drop_write_file(file);
5501 
5502         return ret;
5503 }
5504 
5505 long btrfs_ioctl(struct file *file, unsigned int
5506                 cmd, unsigned long arg)
5507 {
5508         struct inode *inode = file_inode(file);
5509         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5510         struct btrfs_root *root = BTRFS_I(inode)->root;
5511         void __user *argp = (void __user *)arg;
5512 
5513         switch (cmd) {
5514         case FS_IOC_GETFLAGS:
5515                 return btrfs_ioctl_getflags(file, argp);
5516         case FS_IOC_SETFLAGS:
5517                 return btrfs_ioctl_setflags(file, argp);
5518         case FS_IOC_GETVERSION:
5519                 return btrfs_ioctl_getversion(file, argp);
5520         case FITRIM:
5521                 return btrfs_ioctl_fitrim(file, argp);
5522         case BTRFS_IOC_SNAP_CREATE:
5523                 return btrfs_ioctl_snap_create(file, argp, 0);
5524         case BTRFS_IOC_SNAP_CREATE_V2:
5525                 return btrfs_ioctl_snap_create_v2(file, argp, 0);
5526         case BTRFS_IOC_SUBVOL_CREATE:
5527                 return btrfs_ioctl_snap_create(file, argp, 1);
5528         case BTRFS_IOC_SUBVOL_CREATE_V2:
5529                 return btrfs_ioctl_snap_create_v2(file, argp, 1);
5530         case BTRFS_IOC_SNAP_DESTROY:
5531                 return btrfs_ioctl_snap_destroy(file, argp);
5532         case BTRFS_IOC_SUBVOL_GETFLAGS:
5533                 return btrfs_ioctl_subvol_getflags(file, argp);
5534         case BTRFS_IOC_SUBVOL_SETFLAGS:
5535                 return btrfs_ioctl_subvol_setflags(file, argp);
5536         case BTRFS_IOC_DEFAULT_SUBVOL:
5537                 return btrfs_ioctl_default_subvol(file, argp);
5538         case BTRFS_IOC_DEFRAG:
5539                 return btrfs_ioctl_defrag(file, NULL);
5540         case BTRFS_IOC_DEFRAG_RANGE:
5541                 return btrfs_ioctl_defrag(file, argp);
5542         case BTRFS_IOC_RESIZE:
5543                 return btrfs_ioctl_resize(file, argp);
5544         case BTRFS_IOC_ADD_DEV:
5545                 return btrfs_ioctl_add_dev(fs_info, argp);
5546         case BTRFS_IOC_RM_DEV:
5547                 return btrfs_ioctl_rm_dev(file, argp);
5548         case BTRFS_IOC_RM_DEV_V2:
5549                 return btrfs_ioctl_rm_dev_v2(file, argp);
5550         case BTRFS_IOC_FS_INFO:
5551                 return btrfs_ioctl_fs_info(fs_info, argp);
5552         case BTRFS_IOC_DEV_INFO:
5553                 return btrfs_ioctl_dev_info(fs_info, argp);
5554         case BTRFS_IOC_BALANCE:
5555                 return btrfs_ioctl_balance(file, NULL);
5556         case BTRFS_IOC_TRANS_START:
5557                 return btrfs_ioctl_trans_start(file);
5558         case BTRFS_IOC_TRANS_END:
5559                 return btrfs_ioctl_trans_end(file);
5560         case BTRFS_IOC_TREE_SEARCH:
5561                 return btrfs_ioctl_tree_search(file, argp);
5562         case BTRFS_IOC_TREE_SEARCH_V2:
5563                 return btrfs_ioctl_tree_search_v2(file, argp);
5564         case BTRFS_IOC_INO_LOOKUP:
5565                 return btrfs_ioctl_ino_lookup(file, argp);
5566         case BTRFS_IOC_INO_PATHS:
5567                 return btrfs_ioctl_ino_to_path(root, argp);
5568         case BTRFS_IOC_LOGICAL_INO:
5569                 return btrfs_ioctl_logical_to_ino(fs_info, argp);
5570         case BTRFS_IOC_SPACE_INFO:
5571                 return btrfs_ioctl_space_info(fs_info, argp);
5572         case BTRFS_IOC_SYNC: {
5573                 int ret;
5574 
5575                 ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
5576                 if (ret)
5577                         return ret;
5578                 ret = btrfs_sync_fs(inode->i_sb, 1);
5579                 /*
5580                  * The transaction thread may want to do more work,
5581                  * namely it pokes the cleaner kthread that will start
5582                  * processing uncleaned subvols.
5583                  */
5584                 wake_up_process(fs_info->transaction_kthread);
5585                 return ret;
5586         }
5587         case BTRFS_IOC_START_SYNC:
5588                 return btrfs_ioctl_start_sync(root, argp);
5589         case BTRFS_IOC_WAIT_SYNC:
5590                 return btrfs_ioctl_wait_sync(fs_info, argp);
5591         case BTRFS_IOC_SCRUB:
5592                 return btrfs_ioctl_scrub(file, argp);
5593         case BTRFS_IOC_SCRUB_CANCEL:
5594                 return btrfs_ioctl_scrub_cancel(fs_info);
5595         case BTRFS_IOC_SCRUB_PROGRESS:
5596                 return btrfs_ioctl_scrub_progress(fs_info, argp);
5597         case BTRFS_IOC_BALANCE_V2:
5598                 return btrfs_ioctl_balance(file, argp);
5599         case BTRFS_IOC_BALANCE_CTL:
5600                 return btrfs_ioctl_balance_ctl(fs_info, arg);
5601         case BTRFS_IOC_BALANCE_PROGRESS:
5602                 return btrfs_ioctl_balance_progress(fs_info, argp);
5603         case BTRFS_IOC_SET_RECEIVED_SUBVOL:
5604                 return btrfs_ioctl_set_received_subvol(file, argp);
5605 #ifdef CONFIG_64BIT
5606         case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
5607                 return btrfs_ioctl_set_received_subvol_32(file, argp);
5608 #endif
5609         case BTRFS_IOC_SEND:
5610                 return btrfs_ioctl_send(file, argp);
5611         case BTRFS_IOC_GET_DEV_STATS:
5612                 return btrfs_ioctl_get_dev_stats(fs_info, argp);
5613         case BTRFS_IOC_QUOTA_CTL:
5614                 return btrfs_ioctl_quota_ctl(file, argp);
5615         case BTRFS_IOC_QGROUP_ASSIGN:
5616                 return btrfs_ioctl_qgroup_assign(file, argp);
5617         case BTRFS_IOC_QGROUP_CREATE:
5618                 return btrfs_ioctl_qgroup_create(file, argp);
5619         case BTRFS_IOC_QGROUP_LIMIT:
5620                 return btrfs_ioctl_qgroup_limit(file, argp);
5621         case BTRFS_IOC_QUOTA_RESCAN:
5622                 return btrfs_ioctl_quota_rescan(file, argp);
5623         case BTRFS_IOC_QUOTA_RESCAN_STATUS:
5624                 return btrfs_ioctl_quota_rescan_status(file, argp);
5625         case BTRFS_IOC_QUOTA_RESCAN_WAIT:
5626                 return btrfs_ioctl_quota_rescan_wait(file, argp);
5627         case BTRFS_IOC_DEV_REPLACE:
5628                 return btrfs_ioctl_dev_replace(fs_info, argp);
5629         case BTRFS_IOC_GET_FSLABEL:
5630                 return btrfs_ioctl_get_fslabel(file, argp);
5631         case BTRFS_IOC_SET_FSLABEL:
5632                 return btrfs_ioctl_set_fslabel(file, argp);
5633         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
5634                 return btrfs_ioctl_get_supported_features(argp);
5635         case BTRFS_IOC_GET_FEATURES:
5636                 return btrfs_ioctl_get_features(file, argp);
5637         case BTRFS_IOC_SET_FEATURES:
5638                 return btrfs_ioctl_set_features(file, argp);
5639         }
5640 
5641         return -ENOTTY;
5642 }
5643 
5644 #ifdef CONFIG_COMPAT
5645 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5646 {
5647         /*
5648          * These all access 32-bit values anyway so no further
5649          * handling is necessary.
5650          */
5651         switch (cmd) {
5652         case FS_IOC32_GETFLAGS:
5653                 cmd = FS_IOC_GETFLAGS;
5654                 break;
5655         case FS_IOC32_SETFLAGS:
5656                 cmd = FS_IOC_SETFLAGS;
5657                 break;
5658         case FS_IOC32_GETVERSION:
5659                 cmd = FS_IOC_GETVERSION;
5660                 break;
5661         }
5662 
5663         return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
5664 }
5665 #endif
5666 

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