fs/btrfs/ioctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bio.h>
   8 #include <linux/file.h>
   9 #include <linux/fs.h>
  10 #include <linux/fsnotify.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/highmem.h>
  13 #include <linux/time.h>
  14 #include <linux/string.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/mount.h>
  17 #include <linux/namei.h>
  18 #include <linux/writeback.h>
  19 #include <linux/compat.h>
  20 #include <linux/security.h>
  21 #include <linux/xattr.h>
  22 #include <linux/mm.h>
  23 #include <linux/slab.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/uuid.h>
  26 #include <linux/btrfs.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/iversion.h>
  29 #include <linux/fileattr.h>
  30 #include <linux/fsverity.h>
  31 #include <linux/sched/xacct.h>
  32 #include "ctree.h"
  33 #include "disk-io.h"
  34 #include "export.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "volumes.h"
  38 #include "locking.h"
  39 #include "backref.h"
  40 #include "send.h"
  41 #include "dev-replace.h"
  42 #include "props.h"
  43 #include "sysfs.h"
  44 #include "qgroup.h"
  45 #include "tree-log.h"
  46 #include "compression.h"
  47 #include "space-info.h"
  48 #include "block-group.h"
  49 #include "fs.h"
  50 #include "accessors.h"
  51 #include "extent-tree.h"
  52 #include "root-tree.h"
  53 #include "defrag.h"
  54 #include "dir-item.h"
  55 #include "uuid-tree.h"
  56 #include "ioctl.h"
  57 #include "file.h"
  58 #include "scrub.h"
  59 #include "super.h"
  60
  61 #ifdef CONFIG_64BIT
  62 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
  63  * structures are incorrect, as the timespec structure from userspace
  64  * is 4 bytes too small. We define these alternatives here to teach
  65  * the kernel about the 32-bit struct packing.
  66  */
  67 struct btrfs_ioctl_timespec_32 {
  68         __u64 sec;
  69         __u32 nsec;
  70 } __attribute__ ((__packed__));
  71
  72 struct btrfs_ioctl_received_subvol_args_32 {
  73         char    uuid[BTRFS_UUID_SIZE];  /* in */
  74         __u64   stransid;               /* in */
  75         __u64   rtransid;               /* out */
  76         struct btrfs_ioctl_timespec_32 stime; /* in */
  77         struct btrfs_ioctl_timespec_32 rtime; /* out */
  78         __u64   flags;                  /* in */
  79         __u64   reserved[16];           /* in */
  80 } __attribute__ ((__packed__));
  81
  82 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
  83                                 struct btrfs_ioctl_received_subvol_args_32)
  84 #endif
  85
  86 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
  87 struct btrfs_ioctl_send_args_32 {
  88         __s64 send_fd;                  /* in */
  89         __u64 clone_sources_count;      /* in */
  90         compat_uptr_t clone_sources;    /* in */
  91         __u64 parent_root;              /* in */
  92         __u64 flags;                    /* in */
  93         __u32 version;                  /* in */
  94         __u8  reserved[28];             /* in */
  95 } __attribute__ ((__packed__));
  96
  97 #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \
  98                                struct btrfs_ioctl_send_args_32)
  99
 100 struct btrfs_ioctl_encoded_io_args_32 {
 101         compat_uptr_t iov;
 102         compat_ulong_t iovcnt;
 103         __s64 offset;
 104         __u64 flags;
 105         __u64 len;
 106         __u64 unencoded_len;
 107         __u64 unencoded_offset;
 108         __u32 compression;
 109         __u32 encryption;
 110         __u8 reserved[64];
 111 };
 112
 113 #define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \
 114                                        struct btrfs_ioctl_encoded_io_args_32)
 115 #define BTRFS_IOC_ENCODED_WRITE_32 _IOW(BTRFS_IOCTL_MAGIC, 64, \
 116                                         struct btrfs_ioctl_encoded_io_args_32)
 117 #endif
 118
 119 /* Mask out flags that are inappropriate for the given type of inode. */
 120 static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
 121                 unsigned int flags)
 122 {
 123         if (S_ISDIR(inode->i_mode))
 124                 return flags;
 125         else if (S_ISREG(inode->i_mode))
 126                 return flags & ~FS_DIRSYNC_FL;
 127         else
 128                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
 129 }
 130
 131 /*
 132  * Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
 133  * ioctl.
 134  */
 135 static unsigned int btrfs_inode_flags_to_fsflags(struct btrfs_inode *binode)
 136 {
 137         unsigned int iflags = 0;
 138         u32 flags = binode->flags;
 139         u32 ro_flags = binode->ro_flags;
 140
 141         if (flags & BTRFS_INODE_SYNC)
 142                 iflags |= FS_SYNC_FL;
 143         if (flags & BTRFS_INODE_IMMUTABLE)
 144                 iflags |= FS_IMMUTABLE_FL;
 145         if (flags & BTRFS_INODE_APPEND)
 146                 iflags |= FS_APPEND_FL;
 147         if (flags & BTRFS_INODE_NODUMP)
 148                 iflags |= FS_NODUMP_FL;
 149         if (flags & BTRFS_INODE_NOATIME)
 150                 iflags |= FS_NOATIME_FL;
 151         if (flags & BTRFS_INODE_DIRSYNC)
 152                 iflags |= FS_DIRSYNC_FL;
 153         if (flags & BTRFS_INODE_NODATACOW)
 154                 iflags |= FS_NOCOW_FL;
 155         if (ro_flags & BTRFS_INODE_RO_VERITY)
 156                 iflags |= FS_VERITY_FL;
 157
 158         if (flags & BTRFS_INODE_NOCOMPRESS)
 159                 iflags |= FS_NOCOMP_FL;
 160         else if (flags & BTRFS_INODE_COMPRESS)
 161                 iflags |= FS_COMPR_FL;
 162
 163         return iflags;
 164 }
 165
 166 /*
 167  * Update inode->i_flags based on the btrfs internal flags.
 168  */
 169 void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
 170 {
 171         struct btrfs_inode *binode = BTRFS_I(inode);
 172         unsigned int new_fl = 0;
 173
 174         if (binode->flags & BTRFS_INODE_SYNC)
 175                 new_fl |= S_SYNC;
 176         if (binode->flags & BTRFS_INODE_IMMUTABLE)
 177                 new_fl |= S_IMMUTABLE;
 178         if (binode->flags & BTRFS_INODE_APPEND)
 179                 new_fl |= S_APPEND;
 180         if (binode->flags & BTRFS_INODE_NOATIME)
 181                 new_fl |= S_NOATIME;
 182         if (binode->flags & BTRFS_INODE_DIRSYNC)
 183                 new_fl |= S_DIRSYNC;
 184         if (binode->ro_flags & BTRFS_INODE_RO_VERITY)
 185                 new_fl |= S_VERITY;
 186
 187         set_mask_bits(&inode->i_flags,
 188                       S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC |
 189                       S_VERITY, new_fl);
 190 }
 191
 192 /*
 193  * Check if @flags are a supported and valid set of FS_*_FL flags and that
 194  * the old and new flags are not conflicting
 195  */
 196 static int check_fsflags(unsigned int old_flags, unsigned int flags)
 197 {
 198         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
 199                       FS_NOATIME_FL | FS_NODUMP_FL | \
 200                       FS_SYNC_FL | FS_DIRSYNC_FL | \
 201                       FS_NOCOMP_FL | FS_COMPR_FL |
 202                       FS_NOCOW_FL))
 203                 return -EOPNOTSUPP;
 204
 205         /* COMPR and NOCOMP on new/old are valid */
 206         if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
 207                 return -EINVAL;
 208
 209         if ((flags & FS_COMPR_FL) && (flags & FS_NOCOW_FL))
 210                 return -EINVAL;
 211
 212         /* NOCOW and compression options are mutually exclusive */
 213         if ((old_flags & FS_NOCOW_FL) && (flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
 214                 return -EINVAL;
 215         if ((flags & FS_NOCOW_FL) && (old_flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
 216                 return -EINVAL;
 217
 218         return 0;
 219 }
 220
 221 static int check_fsflags_compatible(struct btrfs_fs_info *fs_info,
 222                                     unsigned int flags)
 223 {
 224         if (btrfs_is_zoned(fs_info) && (flags & FS_NOCOW_FL))
 225                 return -EPERM;
 226
 227         return 0;
 228 }
 229
 230 int btrfs_check_ioctl_vol_args_path(const struct btrfs_ioctl_vol_args *vol_args)
 231 {
 232         if (memchr(vol_args->name, 0, sizeof(vol_args->name)) == NULL)
 233                 return -ENAMETOOLONG;
 234         return 0;
 235 }
 236
 237 static int btrfs_check_ioctl_vol_args2_subvol_name(const struct btrfs_ioctl_vol_args_v2 *vol_args2)
 238 {
 239         if (memchr(vol_args2->name, 0, sizeof(vol_args2->name)) == NULL)
 240                 return -ENAMETOOLONG;
 241         return 0;
 242 }
 243
 244 /*
 245  * Set flags/xflags from the internal inode flags. The remaining items of
 246  * fsxattr are zeroed.
 247  */
 248 int btrfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
 249 {
 250         struct btrfs_inode *binode = BTRFS_I(d_inode(dentry));
 251
 252         fileattr_fill_flags(fa, btrfs_inode_flags_to_fsflags(binode));
 253         return 0;
 254 }
 255
 256 int btrfs_fileattr_set(struct mnt_idmap *idmap,
 257                        struct dentry *dentry, struct fileattr *fa)
 258 {
 259         struct inode *inode = d_inode(dentry);
 260         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 261         struct btrfs_inode *binode = BTRFS_I(inode);
 262         struct btrfs_root *root = binode->root;
 263         struct btrfs_trans_handle *trans;
 264         unsigned int fsflags, old_fsflags;
 265         int ret;
 266         const char *comp = NULL;
 267         u32 binode_flags;
 268
 269         if (btrfs_root_readonly(root))
 270                 return -EROFS;
 271
 272         if (fileattr_has_fsx(fa))
 273                 return -EOPNOTSUPP;
 274
 275         fsflags = btrfs_mask_fsflags_for_type(inode, fa->flags);
 276         old_fsflags = btrfs_inode_flags_to_fsflags(binode);
 277         ret = check_fsflags(old_fsflags, fsflags);
 278         if (ret)
 279                 return ret;
 280
 281         ret = check_fsflags_compatible(fs_info, fsflags);
 282         if (ret)
 283                 return ret;
 284
 285         binode_flags = binode->flags;
 286         if (fsflags & FS_SYNC_FL)
 287                 binode_flags |= BTRFS_INODE_SYNC;
 288         else
 289                 binode_flags &= ~BTRFS_INODE_SYNC;
 290         if (fsflags & FS_IMMUTABLE_FL)
 291                 binode_flags |= BTRFS_INODE_IMMUTABLE;
 292         else
 293                 binode_flags &= ~BTRFS_INODE_IMMUTABLE;
 294         if (fsflags & FS_APPEND_FL)
 295                 binode_flags |= BTRFS_INODE_APPEND;
 296         else
 297                 binode_flags &= ~BTRFS_INODE_APPEND;
 298         if (fsflags & FS_NODUMP_FL)
 299                 binode_flags |= BTRFS_INODE_NODUMP;
 300         else
 301                 binode_flags &= ~BTRFS_INODE_NODUMP;
 302         if (fsflags & FS_NOATIME_FL)
 303                 binode_flags |= BTRFS_INODE_NOATIME;
 304         else
 305                 binode_flags &= ~BTRFS_INODE_NOATIME;
 306
 307         /* If coming from FS_IOC_FSSETXATTR then skip unconverted flags */
 308         if (!fa->flags_valid) {
 309                 /* 1 item for the inode */
 310                 trans = btrfs_start_transaction(root, 1);
 311                 if (IS_ERR(trans))
 312                         return PTR_ERR(trans);
 313                 goto update_flags;
 314         }
 315
 316         if (fsflags & FS_DIRSYNC_FL)
 317                 binode_flags |= BTRFS_INODE_DIRSYNC;
 318         else
 319                 binode_flags &= ~BTRFS_INODE_DIRSYNC;
 320         if (fsflags & FS_NOCOW_FL) {
 321                 if (S_ISREG(inode->i_mode)) {
 322                         /*
 323                          * It's safe to turn csums off here, no extents exist.
 324                          * Otherwise we want the flag to reflect the real COW
 325                          * status of the file and will not set it.
 326                          */
 327                         if (inode->i_size == 0)
 328                                 binode_flags |= BTRFS_INODE_NODATACOW |
 329                                                 BTRFS_INODE_NODATASUM;
 330                 } else {
 331                         binode_flags |= BTRFS_INODE_NODATACOW;
 332                 }
 333         } else {
 334                 /*
 335                  * Revert back under same assumptions as above
 336                  */
 337                 if (S_ISREG(inode->i_mode)) {
 338                         if (inode->i_size == 0)
 339                                 binode_flags &= ~(BTRFS_INODE_NODATACOW |
 340                                                   BTRFS_INODE_NODATASUM);
 341                 } else {
 342                         binode_flags &= ~BTRFS_INODE_NODATACOW;
 343                 }
 344         }
 345
 346         /*
 347          * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
 348          * flag may be changed automatically if compression code won't make
 349          * things smaller.
 350          */
 351         if (fsflags & FS_NOCOMP_FL) {
 352                 binode_flags &= ~BTRFS_INODE_COMPRESS;
 353                 binode_flags |= BTRFS_INODE_NOCOMPRESS;
 354         } else if (fsflags & FS_COMPR_FL) {
 355
 356                 if (IS_SWAPFILE(inode))
 357                         return -ETXTBSY;
 358
 359                 binode_flags |= BTRFS_INODE_COMPRESS;
 360                 binode_flags &= ~BTRFS_INODE_NOCOMPRESS;
 361
 362                 comp = btrfs_compress_type2str(fs_info->compress_type);
 363                 if (!comp || comp[0] == 0)
 364                         comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
 365         } else {
 366                 binode_flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 367         }
 368
 369         /*
 370          * 1 for inode item
 371          * 2 for properties
 372          */
 373         trans = btrfs_start_transaction(root, 3);
 374         if (IS_ERR(trans))
 375                 return PTR_ERR(trans);
 376
 377         if (comp) {
 378                 ret = btrfs_set_prop(trans, BTRFS_I(inode), "btrfs.compression",
 379                                      comp, strlen(comp), 0);
 380                 if (ret) {
 381                         btrfs_abort_transaction(trans, ret);
 382                         goto out_end_trans;
 383                 }
 384         } else {
 385                 ret = btrfs_set_prop(trans, BTRFS_I(inode), "btrfs.compression",
 386                                      NULL, 0, 0);
 387                 if (ret && ret != -ENODATA) {
 388                         btrfs_abort_transaction(trans, ret);
 389                         goto out_end_trans;
 390                 }
 391         }
 392
 393 update_flags:
 394         binode->flags = binode_flags;
 395         btrfs_sync_inode_flags_to_i_flags(inode);
 396         inode_inc_iversion(inode);
 397         inode_set_ctime_current(inode);
 398         ret = btrfs_update_inode(trans, BTRFS_I(inode));
 399
 400  out_end_trans:
 401         btrfs_end_transaction(trans);
 402         return ret;
 403 }
 404
 405 /*
 406  * Start exclusive operation @type, return true on success
 407  */
 408 bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
 409                         enum btrfs_exclusive_operation type)
 410 {
 411         bool ret = false;
 412
 413         spin_lock(&fs_info->super_lock);
 414         if (fs_info->exclusive_operation == BTRFS_EXCLOP_NONE) {
 415                 fs_info->exclusive_operation = type;
 416                 ret = true;
 417         }
 418         spin_unlock(&fs_info->super_lock);
 419
 420         return ret;
 421 }
 422
 423 /*
 424  * Conditionally allow to enter the exclusive operation in case it's compatible
 425  * with the running one.  This must be paired with btrfs_exclop_start_unlock and
 426  * btrfs_exclop_finish.
 427  *
 428  * Compatibility:
 429  * - the same type is already running
 430  * - when trying to add a device and balance has been paused
 431  * - not BTRFS_EXCLOP_NONE - this is intentionally incompatible and the caller
 432  *   must check the condition first that would allow none -> @type
 433  */
 434 bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
 435                                  enum btrfs_exclusive_operation type)
 436 {
 437         spin_lock(&fs_info->super_lock);
 438         if (fs_info->exclusive_operation == type ||
 439             (fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED &&
 440              type == BTRFS_EXCLOP_DEV_ADD))
 441                 return true;
 442
 443         spin_unlock(&fs_info->super_lock);
 444         return false;
 445 }
 446
 447 void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info)
 448 {
 449         spin_unlock(&fs_info->super_lock);
 450 }
 451
 452 void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
 453 {
 454         spin_lock(&fs_info->super_lock);
 455         WRITE_ONCE(fs_info->exclusive_operation, BTRFS_EXCLOP_NONE);
 456         spin_unlock(&fs_info->super_lock);
 457         sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");
 458 }
 459
 460 void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
 461                           enum btrfs_exclusive_operation op)
 462 {
 463         switch (op) {
 464         case BTRFS_EXCLOP_BALANCE_PAUSED:
 465                 spin_lock(&fs_info->super_lock);
 466                 ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
 467                        fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD ||
 468                        fs_info->exclusive_operation == BTRFS_EXCLOP_NONE ||
 469                        fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
 470                 fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;
 471                 spin_unlock(&fs_info->super_lock);
 472                 break;
 473         case BTRFS_EXCLOP_BALANCE:
 474                 spin_lock(&fs_info->super_lock);
 475                 ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
 476                 fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
 477                 spin_unlock(&fs_info->super_lock);
 478                 break;
 479         default:
 480                 btrfs_warn(fs_info,
 481                         "invalid exclop balance operation %d requested", op);
 482         }
 483 }
 484
 485 static int btrfs_ioctl_getversion(struct inode *inode, int __user *arg)
 486 {
 487         return put_user(inode->i_generation, arg);
 488 }
 489
 490 static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,
 491                                         void __user *arg)
 492 {
 493         struct btrfs_device *device;
 494         struct fstrim_range range;
 495         u64 minlen = ULLONG_MAX;
 496         u64 num_devices = 0;
 497         int ret;
 498
 499         if (!capable(CAP_SYS_ADMIN))
 500                 return -EPERM;
 501
 502         /*
 503          * btrfs_trim_block_group() depends on space cache, which is not
 504          * available in zoned filesystem. So, disallow fitrim on a zoned
 505          * filesystem for now.
 506          */
 507         if (btrfs_is_zoned(fs_info))
 508                 return -EOPNOTSUPP;
 509
 510         /*
 511          * If the fs is mounted with nologreplay, which requires it to be
 512          * mounted in RO mode as well, we can not allow discard on free space
 513          * inside block groups, because log trees refer to extents that are not
 514          * pinned in a block group's free space cache (pinning the extents is
 515          * precisely the first phase of replaying a log tree).
 516          */
 517         if (btrfs_test_opt(fs_info, NOLOGREPLAY))
 518                 return -EROFS;
 519
 520         rcu_read_lock();
 521         list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
 522                                 dev_list) {
 523                 if (!device->bdev || !bdev_max_discard_sectors(device->bdev))
 524                         continue;
 525                 num_devices++;
 526                 minlen = min_t(u64, bdev_discard_granularity(device->bdev),
 527                                     minlen);
 528         }
 529         rcu_read_unlock();
 530
 531         if (!num_devices)
 532                 return -EOPNOTSUPP;
 533         if (copy_from_user(&range, arg, sizeof(range)))
 534                 return -EFAULT;
 535
 536         /*
 537          * NOTE: Don't truncate the range using super->total_bytes.  Bytenr of
 538          * block group is in the logical address space, which can be any
 539          * sectorsize aligned bytenr in  the range [0, U64_MAX].
 540          */
 541         if (range.len < fs_info->sectorsize)
 542                 return -EINVAL;
 543
 544         range.minlen = max(range.minlen, minlen);
 545         ret = btrfs_trim_fs(fs_info, &range);
 546         if (ret < 0)
 547                 return ret;
 548
 549         if (copy_to_user(arg, &range, sizeof(range)))
 550                 return -EFAULT;
 551
 552         return 0;
 553 }
 554
 555 int __pure btrfs_is_empty_uuid(const u8 *uuid)
 556 {
 557         int i;
 558
 559         for (i = 0; i < BTRFS_UUID_SIZE; i++) {
 560                 if (uuid[i])
 561                         return 0;
 562         }
 563         return 1;
 564 }
 565
 566 /*
 567  * Calculate the number of transaction items to reserve for creating a subvolume
 568  * or snapshot, not including the inode, directory entries, or parent directory.
 569  */
 570 static unsigned int create_subvol_num_items(struct btrfs_qgroup_inherit *inherit)
 571 {
 572         /*
 573          * 1 to add root block
 574          * 1 to add root item
 575          * 1 to add root ref
 576          * 1 to add root backref
 577          * 1 to add UUID item
 578          * 1 to add qgroup info
 579          * 1 to add qgroup limit
 580          *
 581          * Ideally the last two would only be accounted if qgroups are enabled,
 582          * but that can change between now and the time we would insert them.
 583          */
 584         unsigned int num_items = 7;
 585
 586         if (inherit) {
 587                 /* 2 to add qgroup relations for each inherited qgroup */
 588                 num_items += 2 * inherit->num_qgroups;
 589         }
 590         return num_items;
 591 }
 592
 593 static noinline int create_subvol(struct mnt_idmap *idmap,
 594                                   struct inode *dir, struct dentry *dentry,
 595                                   struct btrfs_qgroup_inherit *inherit)
 596 {
 597         struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
 598         struct btrfs_trans_handle *trans;
 599         struct btrfs_key key;
 600         struct btrfs_root_item *root_item;
 601         struct btrfs_inode_item *inode_item;
 602         struct extent_buffer *leaf;
 603         struct btrfs_root *root = BTRFS_I(dir)->root;
 604         struct btrfs_root *new_root;
 605         struct btrfs_block_rsv block_rsv;
 606         struct timespec64 cur_time = current_time(dir);
 607         struct btrfs_new_inode_args new_inode_args = {
 608                 .dir = dir,
 609                 .dentry = dentry,
 610                 .subvol = true,
 611         };
 612         unsigned int trans_num_items;
 613         int ret;
 614         dev_t anon_dev;
 615         u64 objectid;
 616         u64 qgroup_reserved = 0;
 617
 618         root_item = kzalloc(sizeof(*root_item), GFP_KERNEL);
 619         if (!root_item)
 620                 return -ENOMEM;
 621
 622         ret = btrfs_get_free_objectid(fs_info->tree_root, &objectid);
 623         if (ret)
 624                 goto out_root_item;
 625
 626         /*
 627          * Don't create subvolume whose level is not zero. Or qgroup will be
 628          * screwed up since it assumes subvolume qgroup's level to be 0.
 629          */
 630         if (btrfs_qgroup_level(objectid)) {
 631                 ret = -ENOSPC;
 632                 goto out_root_item;
 633         }
 634
 635         ret = get_anon_bdev(&anon_dev);
 636         if (ret < 0)
 637                 goto out_root_item;
 638
 639         new_inode_args.inode = btrfs_new_subvol_inode(idmap, dir);
 640         if (!new_inode_args.inode) {
 641                 ret = -ENOMEM;
 642                 goto out_anon_dev;
 643         }
 644         ret = btrfs_new_inode_prepare(&new_inode_args, &trans_num_items);
 645         if (ret)
 646                 goto out_inode;
 647         trans_num_items += create_subvol_num_items(inherit);
 648
 649         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
 650         ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
 651                                                trans_num_items, false);
 652         if (ret)
 653                 goto out_new_inode_args;
 654         qgroup_reserved = block_rsv.qgroup_rsv_reserved;
 655
 656         trans = btrfs_start_transaction(root, 0);
 657         if (IS_ERR(trans)) {
 658                 ret = PTR_ERR(trans);
 659                 goto out_release_rsv;
 660         }
 661         btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
 662         qgroup_reserved = 0;
 663         trans->block_rsv = &block_rsv;
 664         trans->bytes_reserved = block_rsv.size;
 665
 666         ret = btrfs_qgroup_inherit(trans, 0, objectid, btrfs_root_id(root), inherit);
 667         if (ret)
 668                 goto out;
 669
 670         leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,
 671                                       0, BTRFS_NESTING_NORMAL);
 672         if (IS_ERR(leaf)) {
 673                 ret = PTR_ERR(leaf);
 674                 goto out;
 675         }
 676
 677         btrfs_mark_buffer_dirty(trans, leaf);
 678
 679         inode_item = &root_item->inode;
 680         btrfs_set_stack_inode_generation(inode_item, 1);
 681         btrfs_set_stack_inode_size(inode_item, 3);
 682         btrfs_set_stack_inode_nlink(inode_item, 1);
 683         btrfs_set_stack_inode_nbytes(inode_item,
 684                                      fs_info->nodesize);
 685         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
 686
 687         btrfs_set_root_flags(root_item, 0);
 688         btrfs_set_root_limit(root_item, 0);
 689         btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
 690
 691         btrfs_set_root_bytenr(root_item, leaf->start);
 692         btrfs_set_root_generation(root_item, trans->transid);
 693         btrfs_set_root_level(root_item, 0);
 694         btrfs_set_root_refs(root_item, 1);
 695         btrfs_set_root_used(root_item, leaf->len);
 696         btrfs_set_root_last_snapshot(root_item, 0);
 697
 698         btrfs_set_root_generation_v2(root_item,
 699                         btrfs_root_generation(root_item));
 700         generate_random_guid(root_item->uuid);
 701         btrfs_set_stack_timespec_sec(&root_item->otime, cur_time.tv_sec);
 702         btrfs_set_stack_timespec_nsec(&root_item->otime, cur_time.tv_nsec);
 703         root_item->ctime = root_item->otime;
 704         btrfs_set_root_ctransid(root_item, trans->transid);
 705         btrfs_set_root_otransid(root_item, trans->transid);
 706
 707         btrfs_tree_unlock(leaf);
 708
 709         btrfs_set_root_dirid(root_item, BTRFS_FIRST_FREE_OBJECTID);
 710
 711         key.objectid = objectid;
 712         key.offset = 0;
 713         key.type = BTRFS_ROOT_ITEM_KEY;
 714         ret = btrfs_insert_root(trans, fs_info->tree_root, &key,
 715                                 root_item);
 716         if (ret) {
 717                 int ret2;
 718
 719                 /*
 720                  * Since we don't abort the transaction in this case, free the
 721                  * tree block so that we don't leak space and leave the
 722                  * filesystem in an inconsistent state (an extent item in the
 723                  * extent tree with a backreference for a root that does not
 724                  * exists).
 725                  */
 726                 btrfs_tree_lock(leaf);
 727                 btrfs_clear_buffer_dirty(trans, leaf);
 728                 btrfs_tree_unlock(leaf);
 729                 ret2 = btrfs_free_tree_block(trans, objectid, leaf, 0, 1);
 730                 if (ret2 < 0)
 731                         btrfs_abort_transaction(trans, ret2);
 732                 free_extent_buffer(leaf);
 733                 goto out;
 734         }
 735
 736         free_extent_buffer(leaf);
 737         leaf = NULL;
 738
 739         new_root = btrfs_get_new_fs_root(fs_info, objectid, &anon_dev);
 740         if (IS_ERR(new_root)) {
 741                 ret = PTR_ERR(new_root);
 742                 btrfs_abort_transaction(trans, ret);
 743                 goto out;
 744         }
 745         /* anon_dev is owned by new_root now. */
 746         anon_dev = 0;
 747         BTRFS_I(new_inode_args.inode)->root = new_root;
 748         /* ... and new_root is owned by new_inode_args.inode now. */
 749
 750         ret = btrfs_record_root_in_trans(trans, new_root);
 751         if (ret) {
 752                 btrfs_abort_transaction(trans, ret);
 753                 goto out;
 754         }
 755
 756         ret = btrfs_uuid_tree_add(trans, root_item->uuid,
 757                                   BTRFS_UUID_KEY_SUBVOL, objectid);
 758         if (ret) {
 759                 btrfs_abort_transaction(trans, ret);
 760                 goto out;
 761         }
 762
 763         ret = btrfs_create_new_inode(trans, &new_inode_args);
 764         if (ret) {
 765                 btrfs_abort_transaction(trans, ret);
 766                 goto out;
 767         }
 768
 769         btrfs_record_new_subvolume(trans, BTRFS_I(dir));
 770
 771         d_instantiate_new(dentry, new_inode_args.inode);
 772         new_inode_args.inode = NULL;
 773
 774 out:
 775         trans->block_rsv = NULL;
 776         trans->bytes_reserved = 0;
 777         btrfs_end_transaction(trans);
 778 out_release_rsv:
 779         btrfs_block_rsv_release(fs_info, &block_rsv, (u64)-1, NULL);
 780         if (qgroup_reserved)
 781                 btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
 782 out_new_inode_args:
 783         btrfs_new_inode_args_destroy(&new_inode_args);
 784 out_inode:
 785         iput(new_inode_args.inode);
 786 out_anon_dev:
 787         if (anon_dev)
 788                 free_anon_bdev(anon_dev);
 789 out_root_item:
 790         kfree(root_item);
 791         return ret;
 792 }
 793
 794 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 795                            struct dentry *dentry, bool readonly,
 796                            struct btrfs_qgroup_inherit *inherit)
 797 {
 798         struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
 799         struct inode *inode;
 800         struct btrfs_pending_snapshot *pending_snapshot;
 801         unsigned int trans_num_items;
 802         struct btrfs_trans_handle *trans;
 803         struct btrfs_block_rsv *block_rsv;
 804         u64 qgroup_reserved = 0;
 805         int ret;
 806
 807         /* We do not support snapshotting right now. */
 808         if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
 809                 btrfs_warn(fs_info,
 810                            "extent tree v2 doesn't support snapshotting yet");
 811                 return -EOPNOTSUPP;
 812         }
 813
 814         if (btrfs_root_refs(&root->root_item) == 0)
 815                 return -ENOENT;
 816
 817         if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
 818                 return -EINVAL;
 819
 820         if (atomic_read(&root->nr_swapfiles)) {
 821                 btrfs_warn(fs_info,
 822                            "cannot snapshot subvolume with active swapfile");
 823                 return -ETXTBSY;
 824         }
 825
 826         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
 827         if (!pending_snapshot)
 828                 return -ENOMEM;
 829
 830         ret = get_anon_bdev(&pending_snapshot->anon_dev);
 831         if (ret < 0)
 832                 goto free_pending;
 833         pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item),
 834                         GFP_KERNEL);
 835         pending_snapshot->path = btrfs_alloc_path();
 836         if (!pending_snapshot->root_item || !pending_snapshot->path) {
 837                 ret = -ENOMEM;
 838                 goto free_pending;
 839         }
 840
 841         block_rsv = &pending_snapshot->block_rsv;
 842         btrfs_init_block_rsv(block_rsv, BTRFS_BLOCK_RSV_TEMP);
 843         /*
 844          * 1 to add dir item
 845          * 1 to add dir index
 846          * 1 to update parent inode item
 847          */
 848         trans_num_items = create_subvol_num_items(inherit) + 3;
 849         ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root, block_rsv,
 850                                                trans_num_items, false);
 851         if (ret)
 852                 goto free_pending;
 853         qgroup_reserved = block_rsv->qgroup_rsv_reserved;
 854
 855         pending_snapshot->dentry = dentry;
 856         pending_snapshot->root = root;
 857         pending_snapshot->readonly = readonly;
 858         pending_snapshot->dir = BTRFS_I(dir);
 859         pending_snapshot->inherit = inherit;
 860
 861         trans = btrfs_start_transaction(root, 0);
 862         if (IS_ERR(trans)) {
 863                 ret = PTR_ERR(trans);
 864                 goto fail;
 865         }
 866         ret = btrfs_record_root_in_trans(trans, BTRFS_I(dir)->root);
 867         if (ret) {
 868                 btrfs_end_transaction(trans);
 869                 goto fail;
 870         }
 871         btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
 872         qgroup_reserved = 0;
 873
 874         trans->pending_snapshot = pending_snapshot;
 875
 876         ret = btrfs_commit_transaction(trans);
 877         if (ret)
 878                 goto fail;
 879
 880         ret = pending_snapshot->error;
 881         if (ret)
 882                 goto fail;
 883
 884         ret = btrfs_orphan_cleanup(pending_snapshot->snap);
 885         if (ret)
 886                 goto fail;
 887
 888         inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
 889         if (IS_ERR(inode)) {
 890                 ret = PTR_ERR(inode);
 891                 goto fail;
 892         }
 893
 894         d_instantiate(dentry, inode);
 895         ret = 0;
 896         pending_snapshot->anon_dev = 0;
 897 fail:
 898         /* Prevent double freeing of anon_dev */
 899         if (ret && pending_snapshot->snap)
 900                 pending_snapshot->snap->anon_dev = 0;
 901         btrfs_put_root(pending_snapshot->snap);
 902         btrfs_block_rsv_release(fs_info, block_rsv, (u64)-1, NULL);
 903         if (qgroup_reserved)
 904                 btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
 905 free_pending:
 906         if (pending_snapshot->anon_dev)
 907                 free_anon_bdev(pending_snapshot->anon_dev);
 908         kfree(pending_snapshot->root_item);
 909         btrfs_free_path(pending_snapshot->path);
 910         kfree(pending_snapshot);
 911
 912         return ret;
 913 }
 914
 915 /*  copy of may_delete in fs/namei.c()
 916  *      Check whether we can remove a link victim from directory dir, check
 917  *  whether the type of victim is right.
 918  *  1. We can't do it if dir is read-only (done in permission())
 919  *  2. We should have write and exec permissions on dir
 920  *  3. We can't remove anything from append-only dir
 921  *  4. We can't do anything with immutable dir (done in permission())
 922  *  5. If the sticky bit on dir is set we should either
 923  *      a. be owner of dir, or
 924  *      b. be owner of victim, or
 925  *      c. have CAP_FOWNER capability
 926  *  6. If the victim is append-only or immutable we can't do anything with
 927  *     links pointing to it.
 928  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
 929  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
 930  *  9. We can't remove a root or mountpoint.
 931  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
 932  *     nfs_async_unlink().
 933  */
 934
 935 static int btrfs_may_delete(struct mnt_idmap *idmap,
 936                             struct inode *dir, struct dentry *victim, int isdir)
 937 {
 938         int error;
 939
 940         if (d_really_is_negative(victim))
 941                 return -ENOENT;
 942
 943         /* The @victim is not inside @dir. */
 944         if (d_inode(victim->d_parent) != dir)
 945                 return -EINVAL;
 946         audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 947
 948         error = inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
 949         if (error)
 950                 return error;
 951         if (IS_APPEND(dir))
 952                 return -EPERM;
 953         if (check_sticky(idmap, dir, d_inode(victim)) ||
 954             IS_APPEND(d_inode(victim)) || IS_IMMUTABLE(d_inode(victim)) ||
 955             IS_SWAPFILE(d_inode(victim)))
 956                 return -EPERM;
 957         if (isdir) {
 958                 if (!d_is_dir(victim))
 959                         return -ENOTDIR;
 960                 if (IS_ROOT(victim))
 961                         return -EBUSY;
 962         } else if (d_is_dir(victim))
 963                 return -EISDIR;
 964         if (IS_DEADDIR(dir))
 965                 return -ENOENT;
 966         if (victim->d_flags & DCACHE_NFSFS_RENAMED)
 967                 return -EBUSY;
 968         return 0;
 969 }
 970
 971 /* copy of may_create in fs/namei.c() */
 972 static inline int btrfs_may_create(struct mnt_idmap *idmap,
 973                                    struct inode *dir, struct dentry *child)
 974 {
 975         if (d_really_is_positive(child))
 976                 return -EEXIST;
 977         if (IS_DEADDIR(dir))
 978                 return -ENOENT;
 979         if (!fsuidgid_has_mapping(dir->i_sb, idmap))
 980                 return -EOVERFLOW;
 981         return inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
 982 }
 983
 984 /*
 985  * Create a new subvolume below @parent.  This is largely modeled after
 986  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 987  * inside this filesystem so it's quite a bit simpler.
 988  */
 989 static noinline int btrfs_mksubvol(const struct path *parent,
 990                                    struct mnt_idmap *idmap,
 991                                    const char *name, int namelen,
 992                                    struct btrfs_root *snap_src,
 993                                    bool readonly,
 994                                    struct btrfs_qgroup_inherit *inherit)
 995 {
 996         struct inode *dir = d_inode(parent->dentry);
 997         struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
 998         struct dentry *dentry;
 999         struct fscrypt_str name_str = FSTR_INIT((char *)name, namelen);
1000         int error;
1001
1002         error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
1003         if (error == -EINTR)
1004                 return error;
1005
1006         dentry = lookup_one(idmap, name, parent->dentry, namelen);
1007         error = PTR_ERR(dentry);
1008         if (IS_ERR(dentry))
1009                 goto out_unlock;
1010
1011         error = btrfs_may_create(idmap, dir, dentry);
1012         if (error)
1013                 goto out_dput;
1014
1015         /*
1016          * even if this name doesn't exist, we may get hash collisions.
1017          * check for them now when we can safely fail
1018          */
1019         error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
1020                                                dir->i_ino, &name_str);
1021         if (error)
1022                 goto out_dput;
1023
1024         down_read(&fs_info->subvol_sem);
1025
1026         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
1027                 goto out_up_read;
1028
1029         if (snap_src)
1030                 error = create_snapshot(snap_src, dir, dentry, readonly, inherit);
1031         else
1032                 error = create_subvol(idmap, dir, dentry, inherit);
1033
1034         if (!error)
1035                 fsnotify_mkdir(dir, dentry);
1036 out_up_read:
1037         up_read(&fs_info->subvol_sem);
1038 out_dput:
1039         dput(dentry);
1040 out_unlock:
1041         btrfs_inode_unlock(BTRFS_I(dir), 0);
1042         return error;
1043 }
1044
1045 static noinline int btrfs_mksnapshot(const struct path *parent,
1046                                    struct mnt_idmap *idmap,
1047                                    const char *name, int namelen,
1048                                    struct btrfs_root *root,
1049                                    bool readonly,
1050                                    struct btrfs_qgroup_inherit *inherit)
1051 {
1052         int ret;
1053         bool snapshot_force_cow = false;
1054
1055         /*
1056          * Force new buffered writes to reserve space even when NOCOW is
1057          * possible. This is to avoid later writeback (running dealloc) to
1058          * fallback to COW mode and unexpectedly fail with ENOSPC.
1059          */
1060         btrfs_drew_read_lock(&root->snapshot_lock);
1061
1062         ret = btrfs_start_delalloc_snapshot(root, false);
1063         if (ret)
1064                 goto out;
1065
1066         /*
1067          * All previous writes have started writeback in NOCOW mode, so now
1068          * we force future writes to fallback to COW mode during snapshot
1069          * creation.
1070          */
1071         atomic_inc(&root->snapshot_force_cow);
1072         snapshot_force_cow = true;
1073
1074         btrfs_wait_ordered_extents(root, U64_MAX, NULL);
1075
1076         ret = btrfs_mksubvol(parent, idmap, name, namelen,
1077                              root, readonly, inherit);
1078 out:
1079         if (snapshot_force_cow)
1080                 atomic_dec(&root->snapshot_force_cow);
1081         btrfs_drew_read_unlock(&root->snapshot_lock);
1082         return ret;
1083 }
1084
1085 /*
1086  * Try to start exclusive operation @type or cancel it if it's running.
1087  *
1088  * Return:
1089  *   0        - normal mode, newly claimed op started
1090  *  >0        - normal mode, something else is running,
1091  *              return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS to user space
1092  * ECANCELED  - cancel mode, successful cancel
1093  * ENOTCONN   - cancel mode, operation not running anymore
1094  */
1095 static int exclop_start_or_cancel_reloc(struct btrfs_fs_info *fs_info,
1096                         enum btrfs_exclusive_operation type, bool cancel)
1097 {
1098         if (!cancel) {
1099                 /* Start normal op */
1100                 if (!btrfs_exclop_start(fs_info, type))
1101                         return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1102                 /* Exclusive operation is now claimed */
1103                 return 0;
1104         }
1105
1106         /* Cancel running op */
1107         if (btrfs_exclop_start_try_lock(fs_info, type)) {
1108                 /*
1109                  * This blocks any exclop finish from setting it to NONE, so we
1110                  * request cancellation. Either it runs and we will wait for it,
1111                  * or it has finished and no waiting will happen.
1112                  */
1113                 atomic_inc(&fs_info->reloc_cancel_req);
1114                 btrfs_exclop_start_unlock(fs_info);
1115
1116                 if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
1117                         wait_on_bit(&fs_info->flags, BTRFS_FS_RELOC_RUNNING,
1118                                     TASK_INTERRUPTIBLE);
1119
1120                 return -ECANCELED;
1121         }
1122
1123         /* Something else is running or none */
1124         return -ENOTCONN;
1125 }
1126
1127 static noinline int btrfs_ioctl_resize(struct file *file,
1128                                         void __user *arg)
1129 {
1130         BTRFS_DEV_LOOKUP_ARGS(args);
1131         struct inode *inode = file_inode(file);
1132         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1133         u64 new_size;
1134         u64 old_size;
1135         u64 devid = 1;
1136         struct btrfs_root *root = BTRFS_I(inode)->root;
1137         struct btrfs_ioctl_vol_args *vol_args;
1138         struct btrfs_trans_handle *trans;
1139         struct btrfs_device *device = NULL;
1140         char *sizestr;
1141         char *retptr;
1142         char *devstr = NULL;
1143         int ret = 0;
1144         int mod = 0;
1145         bool cancel;
1146
1147         if (!capable(CAP_SYS_ADMIN))
1148                 return -EPERM;
1149
1150         ret = mnt_want_write_file(file);
1151         if (ret)
1152                 return ret;
1153
1154         /*
1155          * Read the arguments before checking exclusivity to be able to
1156          * distinguish regular resize and cancel
1157          */
1158         vol_args = memdup_user(arg, sizeof(*vol_args));
1159         if (IS_ERR(vol_args)) {
1160                 ret = PTR_ERR(vol_args);
1161                 goto out_drop;
1162         }
1163         ret = btrfs_check_ioctl_vol_args_path(vol_args);
1164         if (ret < 0)
1165                 goto out_free;
1166
1167         sizestr = vol_args->name;
1168         cancel = (strcmp("cancel", sizestr) == 0);
1169         ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_RESIZE, cancel);
1170         if (ret)
1171                 goto out_free;
1172         /* Exclusive operation is now claimed */
1173
1174         devstr = strchr(sizestr, ':');
1175         if (devstr) {
1176                 sizestr = devstr + 1;
1177                 *devstr = '\0';
1178                 devstr = vol_args->name;
1179                 ret = kstrtoull(devstr, 10, &devid);
1180                 if (ret)
1181                         goto out_finish;
1182                 if (!devid) {
1183                         ret = -EINVAL;
1184                         goto out_finish;
1185                 }
1186                 btrfs_info(fs_info, "resizing devid %llu", devid);
1187         }
1188
1189         args.devid = devid;
1190         device = btrfs_find_device(fs_info->fs_devices, &args);
1191         if (!device) {
1192                 btrfs_info(fs_info, "resizer unable to find device %llu",
1193                            devid);
1194                 ret = -ENODEV;
1195                 goto out_finish;
1196         }
1197
1198         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
1199                 btrfs_info(fs_info,
1200                            "resizer unable to apply on readonly device %llu",
1201                        devid);
1202                 ret = -EPERM;
1203                 goto out_finish;
1204         }
1205
1206         if (!strcmp(sizestr, "max"))
1207                 new_size = bdev_nr_bytes(device->bdev);
1208         else {
1209                 if (sizestr[0] == '-') {
1210                         mod = -1;
1211                         sizestr++;
1212                 } else if (sizestr[0] == '+') {
1213                         mod = 1;
1214                         sizestr++;
1215                 }
1216                 new_size = memparse(sizestr, &retptr);
1217                 if (*retptr != '\0' || new_size == 0) {
1218                         ret = -EINVAL;
1219                         goto out_finish;
1220                 }
1221         }
1222
1223         if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
1224                 ret = -EPERM;
1225                 goto out_finish;
1226         }
1227
1228         old_size = btrfs_device_get_total_bytes(device);
1229
1230         if (mod < 0) {
1231                 if (new_size > old_size) {
1232                         ret = -EINVAL;
1233                         goto out_finish;
1234                 }
1235                 new_size = old_size - new_size;
1236         } else if (mod > 0) {
1237                 if (new_size > ULLONG_MAX - old_size) {
1238                         ret = -ERANGE;
1239                         goto out_finish;
1240                 }
1241                 new_size = old_size + new_size;
1242         }
1243
1244         if (new_size < SZ_256M) {
1245                 ret = -EINVAL;
1246                 goto out_finish;
1247         }
1248         if (new_size > bdev_nr_bytes(device->bdev)) {
1249                 ret = -EFBIG;
1250                 goto out_finish;
1251         }
1252
1253         new_size = round_down(new_size, fs_info->sectorsize);
1254
1255         if (new_size > old_size) {
1256                 trans = btrfs_start_transaction(root, 0);
1257                 if (IS_ERR(trans)) {
1258                         ret = PTR_ERR(trans);
1259                         goto out_finish;
1260                 }
1261                 ret = btrfs_grow_device(trans, device, new_size);
1262                 btrfs_commit_transaction(trans);
1263         } else if (new_size < old_size) {
1264                 ret = btrfs_shrink_device(device, new_size);
1265         } /* equal, nothing need to do */
1266
1267         if (ret == 0 && new_size != old_size)
1268                 btrfs_info_in_rcu(fs_info,
1269                         "resize device %s (devid %llu) from %llu to %llu",
1270                         btrfs_dev_name(device), device->devid,
1271                         old_size, new_size);
1272 out_finish:
1273         btrfs_exclop_finish(fs_info);
1274 out_free:
1275         kfree(vol_args);
1276 out_drop:
1277         mnt_drop_write_file(file);
1278         return ret;
1279 }
1280
1281 static noinline int __btrfs_ioctl_snap_create(struct file *file,
1282                                 struct mnt_idmap *idmap,
1283                                 const char *name, unsigned long fd, int subvol,
1284                                 bool readonly,
1285                                 struct btrfs_qgroup_inherit *inherit)
1286 {
1287         int namelen;
1288         int ret = 0;
1289
1290         if (!S_ISDIR(file_inode(file)->i_mode))
1291                 return -ENOTDIR;
1292
1293         ret = mnt_want_write_file(file);
1294         if (ret)
1295                 goto out;
1296
1297         namelen = strlen(name);
1298         if (strchr(name, '/')) {
1299                 ret = -EINVAL;
1300                 goto out_drop_write;
1301         }
1302
1303         if (name[0] == '.' &&
1304            (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1305                 ret = -EEXIST;
1306                 goto out_drop_write;
1307         }
1308
1309         if (subvol) {
1310                 ret = btrfs_mksubvol(&file->f_path, idmap, name,
1311                                      namelen, NULL, readonly, inherit);
1312         } else {
1313                 struct fd src = fdget(fd);
1314                 struct inode *src_inode;
1315                 if (!src.file) {
1316                         ret = -EINVAL;
1317                         goto out_drop_write;
1318                 }
1319
1320                 src_inode = file_inode(src.file);
1321                 if (src_inode->i_sb != file_inode(file)->i_sb) {
1322                         btrfs_info(BTRFS_I(file_inode(file))->root->fs_info,
1323                                    "Snapshot src from another FS");
1324                         ret = -EXDEV;
1325                 } else if (!inode_owner_or_capable(idmap, src_inode)) {
1326                         /*
1327                          * Subvolume creation is not restricted, but snapshots
1328                          * are limited to own subvolumes only
1329                          */
1330                         ret = -EPERM;
1331                 } else if (btrfs_ino(BTRFS_I(src_inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1332                         /*
1333                          * Snapshots must be made with the src_inode referring
1334                          * to the subvolume inode, otherwise the permission
1335                          * checking above is useless because we may have
1336                          * permission on a lower directory but not the subvol
1337                          * itself.
1338                          */
1339                         ret = -EINVAL;
1340                 } else {
1341                         ret = btrfs_mksnapshot(&file->f_path, idmap,
1342                                                name, namelen,
1343                                                BTRFS_I(src_inode)->root,
1344                                                readonly, inherit);
1345                 }
1346                 fdput(src);
1347         }
1348 out_drop_write:
1349         mnt_drop_write_file(file);
1350 out:
1351         return ret;
1352 }
1353
1354 static noinline int btrfs_ioctl_snap_create(struct file *file,
1355                                             void __user *arg, int subvol)
1356 {
1357         struct btrfs_ioctl_vol_args *vol_args;
1358         int ret;
1359
1360         if (!S_ISDIR(file_inode(file)->i_mode))
1361                 return -ENOTDIR;
1362
1363         vol_args = memdup_user(arg, sizeof(*vol_args));
1364         if (IS_ERR(vol_args))
1365                 return PTR_ERR(vol_args);
1366         ret = btrfs_check_ioctl_vol_args_path(vol_args);
1367         if (ret < 0)
1368                 goto out;
1369
1370         ret = __btrfs_ioctl_snap_create(file, file_mnt_idmap(file),
1371                                         vol_args->name, vol_args->fd, subvol,
1372                                         false, NULL);
1373
1374 out:
1375         kfree(vol_args);
1376         return ret;
1377 }
1378
1379 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1380                                                void __user *arg, int subvol)
1381 {
1382         struct btrfs_ioctl_vol_args_v2 *vol_args;
1383         int ret;
1384         bool readonly = false;
1385         struct btrfs_qgroup_inherit *inherit = NULL;
1386
1387         if (!S_ISDIR(file_inode(file)->i_mode))
1388                 return -ENOTDIR;
1389
1390         vol_args = memdup_user(arg, sizeof(*vol_args));
1391         if (IS_ERR(vol_args))
1392                 return PTR_ERR(vol_args);
1393         ret = btrfs_check_ioctl_vol_args2_subvol_name(vol_args);
1394         if (ret < 0)
1395                 goto free_args;
1396
1397         if (vol_args->flags & ~BTRFS_SUBVOL_CREATE_ARGS_MASK) {
1398                 ret = -EOPNOTSUPP;
1399                 goto free_args;
1400         }
1401
1402         if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1403                 readonly = true;
1404         if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1405                 struct btrfs_fs_info *fs_info = inode_to_fs_info(file_inode(file));
1406
1407                 if (vol_args->size < sizeof(*inherit) ||
1408                     vol_args->size > PAGE_SIZE) {
1409                         ret = -EINVAL;
1410                         goto free_args;
1411                 }
1412                 inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1413                 if (IS_ERR(inherit)) {
1414                         ret = PTR_ERR(inherit);
1415                         goto free_args;
1416                 }
1417
1418                 ret = btrfs_qgroup_check_inherit(fs_info, inherit, vol_args->size);
1419                 if (ret < 0)
1420                         goto free_inherit;
1421         }
1422
1423         ret = __btrfs_ioctl_snap_create(file, file_mnt_idmap(file),
1424                                         vol_args->name, vol_args->fd, subvol,
1425                                         readonly, inherit);
1426         if (ret)
1427                 goto free_inherit;
1428 free_inherit:
1429         kfree(inherit);
1430 free_args:
1431         kfree(vol_args);
1432         return ret;
1433 }
1434
1435 static noinline int btrfs_ioctl_subvol_getflags(struct inode *inode,
1436                                                 void __user *arg)
1437 {
1438         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1439         struct btrfs_root *root = BTRFS_I(inode)->root;
1440         int ret = 0;
1441         u64 flags = 0;
1442
1443         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID)
1444                 return -EINVAL;
1445
1446         down_read(&fs_info->subvol_sem);
1447         if (btrfs_root_readonly(root))
1448                 flags |= BTRFS_SUBVOL_RDONLY;
1449         up_read(&fs_info->subvol_sem);
1450
1451         if (copy_to_user(arg, &flags, sizeof(flags)))
1452                 ret = -EFAULT;
1453
1454         return ret;
1455 }
1456
1457 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1458                                               void __user *arg)
1459 {
1460         struct inode *inode = file_inode(file);
1461         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1462         struct btrfs_root *root = BTRFS_I(inode)->root;
1463         struct btrfs_trans_handle *trans;
1464         u64 root_flags;
1465         u64 flags;
1466         int ret = 0;
1467
1468         if (!inode_owner_or_capable(file_mnt_idmap(file), inode))
1469                 return -EPERM;
1470
1471         ret = mnt_want_write_file(file);
1472         if (ret)
1473                 goto out;
1474
1475         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1476                 ret = -EINVAL;
1477                 goto out_drop_write;
1478         }
1479
1480         if (copy_from_user(&flags, arg, sizeof(flags))) {
1481                 ret = -EFAULT;
1482                 goto out_drop_write;
1483         }
1484
1485         if (flags & ~BTRFS_SUBVOL_RDONLY) {
1486                 ret = -EOPNOTSUPP;
1487                 goto out_drop_write;
1488         }
1489
1490         down_write(&fs_info->subvol_sem);
1491
1492         /* nothing to do */
1493         if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1494                 goto out_drop_sem;
1495
1496         root_flags = btrfs_root_flags(&root->root_item);
1497         if (flags & BTRFS_SUBVOL_RDONLY) {
1498                 btrfs_set_root_flags(&root->root_item,
1499                                      root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1500         } else {
1501                 /*
1502                  * Block RO -> RW transition if this subvolume is involved in
1503                  * send
1504                  */
1505                 spin_lock(&root->root_item_lock);
1506                 if (root->send_in_progress == 0) {
1507                         btrfs_set_root_flags(&root->root_item,
1508                                      root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1509                         spin_unlock(&root->root_item_lock);
1510                 } else {
1511                         spin_unlock(&root->root_item_lock);
1512                         btrfs_warn(fs_info,
1513                                    "Attempt to set subvolume %llu read-write during send",
1514                                    btrfs_root_id(root));
1515                         ret = -EPERM;
1516                         goto out_drop_sem;
1517                 }
1518         }
1519
1520         trans = btrfs_start_transaction(root, 1);
1521         if (IS_ERR(trans)) {
1522                 ret = PTR_ERR(trans);
1523                 goto out_reset;
1524         }
1525
1526         ret = btrfs_update_root(trans, fs_info->tree_root,
1527                                 &root->root_key, &root->root_item);
1528         if (ret < 0) {
1529                 btrfs_end_transaction(trans);
1530                 goto out_reset;
1531         }
1532
1533         ret = btrfs_commit_transaction(trans);
1534
1535 out_reset:
1536         if (ret)
1537                 btrfs_set_root_flags(&root->root_item, root_flags);
1538 out_drop_sem:
1539         up_write(&fs_info->subvol_sem);
1540 out_drop_write:
1541         mnt_drop_write_file(file);
1542 out:
1543         return ret;
1544 }
1545
1546 static noinline int key_in_sk(struct btrfs_key *key,
1547                               struct btrfs_ioctl_search_key *sk)
1548 {
1549         struct btrfs_key test;
1550         int ret;
1551
1552         test.objectid = sk->min_objectid;
1553         test.type = sk->min_type;
1554         test.offset = sk->min_offset;
1555
1556         ret = btrfs_comp_cpu_keys(key, &test);
1557         if (ret < 0)
1558                 return 0;
1559
1560         test.objectid = sk->max_objectid;
1561         test.type = sk->max_type;
1562         test.offset = sk->max_offset;
1563
1564         ret = btrfs_comp_cpu_keys(key, &test);
1565         if (ret > 0)
1566                 return 0;
1567         return 1;
1568 }
1569
1570 static noinline int copy_to_sk(struct btrfs_path *path,
1571                                struct btrfs_key *key,
1572                                struct btrfs_ioctl_search_key *sk,
1573                                u64 *buf_size,
1574                                char __user *ubuf,
1575                                unsigned long *sk_offset,
1576                                int *num_found)
1577 {
1578         u64 found_transid;
1579         struct extent_buffer *leaf;
1580         struct btrfs_ioctl_search_header sh;
1581         struct btrfs_key test;
1582         unsigned long item_off;
1583         unsigned long item_len;
1584         int nritems;
1585         int i;
1586         int slot;
1587         int ret = 0;
1588
1589         leaf = path->nodes[0];
1590         slot = path->slots[0];
1591         nritems = btrfs_header_nritems(leaf);
1592
1593         if (btrfs_header_generation(leaf) > sk->max_transid) {
1594                 i = nritems;
1595                 goto advance_key;
1596         }
1597         found_transid = btrfs_header_generation(leaf);
1598
1599         for (i = slot; i < nritems; i++) {
1600                 item_off = btrfs_item_ptr_offset(leaf, i);
1601                 item_len = btrfs_item_size(leaf, i);
1602
1603                 btrfs_item_key_to_cpu(leaf, key, i);
1604                 if (!key_in_sk(key, sk))
1605                         continue;
1606
1607                 if (sizeof(sh) + item_len > *buf_size) {
1608                         if (*num_found) {
1609                                 ret = 1;
1610                                 goto out;
1611                         }
1612
1613                         /*
1614                          * return one empty item back for v1, which does not
1615                          * handle -EOVERFLOW
1616                          */
1617
1618                         *buf_size = sizeof(sh) + item_len;
1619                         item_len = 0;
1620                         ret = -EOVERFLOW;
1621                 }
1622
1623                 if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
1624                         ret = 1;
1625                         goto out;
1626                 }
1627
1628                 sh.objectid = key->objectid;
1629                 sh.offset = key->offset;
1630                 sh.type = key->type;
1631                 sh.len = item_len;
1632                 sh.transid = found_transid;
1633
1634                 /*
1635                  * Copy search result header. If we fault then loop again so we
1636                  * can fault in the pages and -EFAULT there if there's a
1637                  * problem. Otherwise we'll fault and then copy the buffer in
1638                  * properly this next time through
1639                  */
1640                 if (copy_to_user_nofault(ubuf + *sk_offset, &sh, sizeof(sh))) {
1641                         ret = 0;
1642                         goto out;
1643                 }
1644
1645                 *sk_offset += sizeof(sh);
1646
1647                 if (item_len) {
1648                         char __user *up = ubuf + *sk_offset;
1649                         /*
1650                          * Copy the item, same behavior as above, but reset the
1651                          * * sk_offset so we copy the full thing again.
1652                          */
1653                         if (read_extent_buffer_to_user_nofault(leaf, up,
1654                                                 item_off, item_len)) {
1655                                 ret = 0;
1656                                 *sk_offset -= sizeof(sh);
1657                                 goto out;
1658                         }
1659
1660                         *sk_offset += item_len;
1661                 }
1662                 (*num_found)++;
1663
1664                 if (ret) /* -EOVERFLOW from above */
1665                         goto out;
1666
1667                 if (*num_found >= sk->nr_items) {
1668                         ret = 1;
1669                         goto out;
1670                 }
1671         }
1672 advance_key:
1673         ret = 0;
1674         test.objectid = sk->max_objectid;
1675         test.type = sk->max_type;
1676         test.offset = sk->max_offset;
1677         if (btrfs_comp_cpu_keys(key, &test) >= 0)
1678                 ret = 1;
1679         else if (key->offset < (u64)-1)
1680                 key->offset++;
1681         else if (key->type < (u8)-1) {
1682                 key->offset = 0;
1683                 key->type++;
1684         } else if (key->objectid < (u64)-1) {
1685                 key->offset = 0;
1686                 key->type = 0;
1687                 key->objectid++;
1688         } else
1689                 ret = 1;
1690 out:
1691         /*
1692          *  0: all items from this leaf copied, continue with next
1693          *  1: * more items can be copied, but unused buffer is too small
1694          *     * all items were found
1695          *     Either way, it will stops the loop which iterates to the next
1696          *     leaf
1697          *  -EOVERFLOW: item was to large for buffer
1698          *  -EFAULT: could not copy extent buffer back to userspace
1699          */
1700         return ret;
1701 }
1702
1703 static noinline int search_ioctl(struct inode *inode,
1704                                  struct btrfs_ioctl_search_key *sk,
1705                                  u64 *buf_size,
1706                                  char __user *ubuf)
1707 {
1708         struct btrfs_fs_info *info = inode_to_fs_info(inode);
1709         struct btrfs_root *root;
1710         struct btrfs_key key;
1711         struct btrfs_path *path;
1712         int ret;
1713         int num_found = 0;
1714         unsigned long sk_offset = 0;
1715
1716         if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
1717                 *buf_size = sizeof(struct btrfs_ioctl_search_header);
1718                 return -EOVERFLOW;
1719         }
1720
1721         path = btrfs_alloc_path();
1722         if (!path)
1723                 return -ENOMEM;
1724
1725         if (sk->tree_id == 0) {
1726                 /* search the root of the inode that was passed */
1727                 root = btrfs_grab_root(BTRFS_I(inode)->root);
1728         } else {
1729                 root = btrfs_get_fs_root(info, sk->tree_id, true);
1730                 if (IS_ERR(root)) {
1731                         btrfs_free_path(path);
1732                         return PTR_ERR(root);
1733                 }
1734         }
1735
1736         key.objectid = sk->min_objectid;
1737         key.type = sk->min_type;
1738         key.offset = sk->min_offset;
1739
1740         while (1) {
1741                 ret = -EFAULT;
1742                 /*
1743                  * Ensure that the whole user buffer is faulted in at sub-page
1744                  * granularity, otherwise the loop may live-lock.
1745                  */
1746                 if (fault_in_subpage_writeable(ubuf + sk_offset,
1747                                                *buf_size - sk_offset))
1748                         break;
1749
1750                 ret = btrfs_search_forward(root, &key, path, sk->min_transid);
1751                 if (ret != 0) {
1752                         if (ret > 0)
1753                                 ret = 0;
1754                         goto err;
1755                 }
1756                 ret = copy_to_sk(path, &key, sk, buf_size, ubuf,
1757                                  &sk_offset, &num_found);
1758                 btrfs_release_path(path);
1759                 if (ret)
1760                         break;
1761
1762         }
1763         if (ret > 0)
1764                 ret = 0;
1765 err:
1766         sk->nr_items = num_found;
1767         btrfs_put_root(root);
1768         btrfs_free_path(path);
1769         return ret;
1770 }
1771
1772 static noinline int btrfs_ioctl_tree_search(struct inode *inode,
1773                                             void __user *argp)
1774 {
1775         struct btrfs_ioctl_search_args __user *uargs = argp;
1776         struct btrfs_ioctl_search_key sk;
1777         int ret;
1778         u64 buf_size;
1779
1780         if (!capable(CAP_SYS_ADMIN))
1781                 return -EPERM;
1782
1783         if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
1784                 return -EFAULT;
1785
1786         buf_size = sizeof(uargs->buf);
1787
1788         ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
1789
1790         /*
1791          * In the origin implementation an overflow is handled by returning a
1792          * search header with a len of zero, so reset ret.
1793          */
1794         if (ret == -EOVERFLOW)
1795                 ret = 0;
1796
1797         if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
1798                 ret = -EFAULT;
1799         return ret;
1800 }
1801
1802 static noinline int btrfs_ioctl_tree_search_v2(struct inode *inode,
1803                                                void __user *argp)
1804 {
1805         struct btrfs_ioctl_search_args_v2 __user *uarg = argp;
1806         struct btrfs_ioctl_search_args_v2 args;
1807         int ret;
1808         u64 buf_size;
1809         const u64 buf_limit = SZ_16M;
1810
1811         if (!capable(CAP_SYS_ADMIN))
1812                 return -EPERM;
1813
1814         /* copy search header and buffer size */
1815         if (copy_from_user(&args, uarg, sizeof(args)))
1816                 return -EFAULT;
1817
1818         buf_size = args.buf_size;
1819
1820         /* limit result size to 16MB */
1821         if (buf_size > buf_limit)
1822                 buf_size = buf_limit;
1823
1824         ret = search_ioctl(inode, &args.key, &buf_size,
1825                            (char __user *)(&uarg->buf[0]));
1826         if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
1827                 ret = -EFAULT;
1828         else if (ret == -EOVERFLOW &&
1829                 copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
1830                 ret = -EFAULT;
1831
1832         return ret;
1833 }
1834
1835 /*
1836  * Search INODE_REFs to identify path name of 'dirid' directory
1837  * in a 'tree_id' tree. and sets path name to 'name'.
1838  */
1839 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
1840                                 u64 tree_id, u64 dirid, char *name)
1841 {
1842         struct btrfs_root *root;
1843         struct btrfs_key key;
1844         char *ptr;
1845         int ret = -1;
1846         int slot;
1847         int len;
1848         int total_len = 0;
1849         struct btrfs_inode_ref *iref;
1850         struct extent_buffer *l;
1851         struct btrfs_path *path;
1852
1853         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
1854                 name[0]='\0';
1855                 return 0;
1856         }
1857
1858         path = btrfs_alloc_path();
1859         if (!path)
1860                 return -ENOMEM;
1861
1862         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX - 1];
1863
1864         root = btrfs_get_fs_root(info, tree_id, true);
1865         if (IS_ERR(root)) {
1866                 ret = PTR_ERR(root);
1867                 root = NULL;
1868                 goto out;
1869         }
1870
1871         key.objectid = dirid;
1872         key.type = BTRFS_INODE_REF_KEY;
1873         key.offset = (u64)-1;
1874
1875         while (1) {
1876                 ret = btrfs_search_backwards(root, &key, path);
1877                 if (ret < 0)
1878                         goto out;
1879                 else if (ret > 0) {
1880                         ret = -ENOENT;
1881                         goto out;
1882                 }
1883
1884                 l = path->nodes[0];
1885                 slot = path->slots[0];
1886
1887                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
1888                 len = btrfs_inode_ref_name_len(l, iref);
1889                 ptr -= len + 1;
1890                 total_len += len + 1;
1891                 if (ptr < name) {
1892                         ret = -ENAMETOOLONG;
1893                         goto out;
1894                 }
1895
1896                 *(ptr + len) = '/';
1897                 read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
1898
1899                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
1900                         break;
1901
1902                 btrfs_release_path(path);
1903                 key.objectid = key.offset;
1904                 key.offset = (u64)-1;
1905                 dirid = key.objectid;
1906         }
1907         memmove(name, ptr, total_len);
1908         name[total_len] = '\0';
1909         ret = 0;
1910 out:
1911         btrfs_put_root(root);
1912         btrfs_free_path(path);
1913         return ret;
1914 }
1915
1916 static int btrfs_search_path_in_tree_user(struct mnt_idmap *idmap,
1917                                 struct inode *inode,
1918                                 struct btrfs_ioctl_ino_lookup_user_args *args)
1919 {
1920         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1921         u64 upper_limit = btrfs_ino(BTRFS_I(inode));
1922         u64 treeid = btrfs_root_id(BTRFS_I(inode)->root);
1923         u64 dirid = args->dirid;
1924         unsigned long item_off;
1925         unsigned long item_len;
1926         struct btrfs_inode_ref *iref;
1927         struct btrfs_root_ref *rref;
1928         struct btrfs_root *root = NULL;
1929         struct btrfs_path *path;
1930         struct btrfs_key key, key2;
1931         struct extent_buffer *leaf;
1932         struct inode *temp_inode;
1933         char *ptr;
1934         int slot;
1935         int len;
1936         int total_len = 0;
1937         int ret;
1938
1939         path = btrfs_alloc_path();
1940         if (!path)
1941                 return -ENOMEM;
1942
1943         /*
1944          * If the bottom subvolume does not exist directly under upper_limit,
1945          * construct the path in from the bottom up.
1946          */
1947         if (dirid != upper_limit) {
1948                 ptr = &args->path[BTRFS_INO_LOOKUP_USER_PATH_MAX - 1];
1949
1950                 root = btrfs_get_fs_root(fs_info, treeid, true);
1951                 if (IS_ERR(root)) {
1952                         ret = PTR_ERR(root);
1953                         goto out;
1954                 }
1955
1956                 key.objectid = dirid;
1957                 key.type = BTRFS_INODE_REF_KEY;
1958                 key.offset = (u64)-1;
1959                 while (1) {
1960                         ret = btrfs_search_backwards(root, &key, path);
1961                         if (ret < 0)
1962                                 goto out_put;
1963                         else if (ret > 0) {
1964                                 ret = -ENOENT;
1965                                 goto out_put;
1966                         }
1967
1968                         leaf = path->nodes[0];
1969                         slot = path->slots[0];
1970
1971                         iref = btrfs_item_ptr(leaf, slot, struct btrfs_inode_ref);
1972                         len = btrfs_inode_ref_name_len(leaf, iref);
1973                         ptr -= len + 1;
1974                         total_len += len + 1;
1975                         if (ptr < args->path) {
1976                                 ret = -ENAMETOOLONG;
1977                                 goto out_put;
1978                         }
1979
1980                         *(ptr + len) = '/';
1981                         read_extent_buffer(leaf, ptr,
1982                                         (unsigned long)(iref + 1), len);
1983
1984                         /* Check the read+exec permission of this directory */
1985                         ret = btrfs_previous_item(root, path, dirid,
1986                                                   BTRFS_INODE_ITEM_KEY);
1987                         if (ret < 0) {
1988                                 goto out_put;
1989                         } else if (ret > 0) {
1990                                 ret = -ENOENT;
1991                                 goto out_put;
1992                         }
1993
1994                         leaf = path->nodes[0];
1995                         slot = path->slots[0];
1996                         btrfs_item_key_to_cpu(leaf, &key2, slot);
1997                         if (key2.objectid != dirid) {
1998                                 ret = -ENOENT;
1999                                 goto out_put;
2000                         }
2001
2002                         /*
2003                          * We don't need the path anymore, so release it and
2004                          * avoid deadlocks and lockdep warnings in case
2005                          * btrfs_iget() needs to lookup the inode from its root
2006                          * btree and lock the same leaf.
2007                          */
2008                         btrfs_release_path(path);
2009                         temp_inode = btrfs_iget(key2.objectid, root);
2010                         if (IS_ERR(temp_inode)) {
2011                                 ret = PTR_ERR(temp_inode);
2012                                 goto out_put;
2013                         }
2014                         ret = inode_permission(idmap, temp_inode,
2015                                                MAY_READ | MAY_EXEC);
2016                         iput(temp_inode);
2017                         if (ret) {
2018                                 ret = -EACCES;
2019                                 goto out_put;
2020                         }
2021
2022                         if (key.offset == upper_limit)
2023                                 break;
2024                         if (key.objectid == BTRFS_FIRST_FREE_OBJECTID) {
2025                                 ret = -EACCES;
2026                                 goto out_put;
2027                         }
2028
2029                         key.objectid = key.offset;
2030                         key.offset = (u64)-1;
2031                         dirid = key.objectid;
2032                 }
2033
2034                 memmove(args->path, ptr, total_len);
2035                 args->path[total_len] = '\0';
2036                 btrfs_put_root(root);
2037                 root = NULL;
2038                 btrfs_release_path(path);
2039         }
2040
2041         /* Get the bottom subvolume's name from ROOT_REF */
2042         key.objectid = treeid;
2043         key.type = BTRFS_ROOT_REF_KEY;
2044         key.offset = args->treeid;
2045         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2046         if (ret < 0) {
2047                 goto out;
2048         } else if (ret > 0) {
2049                 ret = -ENOENT;
2050                 goto out;
2051         }
2052
2053         leaf = path->nodes[0];
2054         slot = path->slots[0];
2055         btrfs_item_key_to_cpu(leaf, &key, slot);
2056
2057         item_off = btrfs_item_ptr_offset(leaf, slot);
2058         item_len = btrfs_item_size(leaf, slot);
2059         /* Check if dirid in ROOT_REF corresponds to passed dirid */
2060         rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2061         if (args->dirid != btrfs_root_ref_dirid(leaf, rref)) {
2062                 ret = -EINVAL;
2063                 goto out;
2064         }
2065
2066         /* Copy subvolume's name */
2067         item_off += sizeof(struct btrfs_root_ref);
2068         item_len -= sizeof(struct btrfs_root_ref);
2069         read_extent_buffer(leaf, args->name, item_off, item_len);
2070         args->name[item_len] = 0;
2071
2072 out_put:
2073         btrfs_put_root(root);
2074 out:
2075         btrfs_free_path(path);
2076         return ret;
2077 }
2078
2079 static noinline int btrfs_ioctl_ino_lookup(struct btrfs_root *root,
2080                                            void __user *argp)
2081 {
2082         struct btrfs_ioctl_ino_lookup_args *args;
2083         int ret = 0;
2084
2085         args = memdup_user(argp, sizeof(*args));
2086         if (IS_ERR(args))
2087                 return PTR_ERR(args);
2088
2089         /*
2090          * Unprivileged query to obtain the containing subvolume root id. The
2091          * path is reset so it's consistent with btrfs_search_path_in_tree.
2092          */
2093         if (args->treeid == 0)
2094                 args->treeid = btrfs_root_id(root);
2095
2096         if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2097                 args->name[0] = 0;
2098                 goto out;
2099         }
2100
2101         if (!capable(CAP_SYS_ADMIN)) {
2102                 ret = -EPERM;
2103                 goto out;
2104         }
2105
2106         ret = btrfs_search_path_in_tree(root->fs_info,
2107                                         args->treeid, args->objectid,
2108                                         args->name);
2109
2110 out:
2111         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2112                 ret = -EFAULT;
2113
2114         kfree(args);
2115         return ret;
2116 }
2117
2118 /*
2119  * Version of ino_lookup ioctl (unprivileged)
2120  *
2121  * The main differences from ino_lookup ioctl are:
2122  *
2123  *   1. Read + Exec permission will be checked using inode_permission() during
2124  *      path construction. -EACCES will be returned in case of failure.
2125  *   2. Path construction will be stopped at the inode number which corresponds
2126  *      to the fd with which this ioctl is called. If constructed path does not
2127  *      exist under fd's inode, -EACCES will be returned.
2128  *   3. The name of bottom subvolume is also searched and filled.
2129  */
2130 static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp)
2131 {
2132         struct btrfs_ioctl_ino_lookup_user_args *args;
2133         struct inode *inode;
2134         int ret;
2135
2136         args = memdup_user(argp, sizeof(*args));
2137         if (IS_ERR(args))
2138                 return PTR_ERR(args);
2139
2140         inode = file_inode(file);
2141
2142         if (args->dirid == BTRFS_FIRST_FREE_OBJECTID &&
2143             btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2144                 /*
2145                  * The subvolume does not exist under fd with which this is
2146                  * called
2147                  */
2148                 kfree(args);
2149                 return -EACCES;
2150         }
2151
2152         ret = btrfs_search_path_in_tree_user(file_mnt_idmap(file), inode, args);
2153
2154         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2155                 ret = -EFAULT;
2156
2157         kfree(args);
2158         return ret;
2159 }
2160
2161 /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */
2162 static int btrfs_ioctl_get_subvol_info(struct inode *inode, void __user *argp)
2163 {
2164         struct btrfs_ioctl_get_subvol_info_args *subvol_info;
2165         struct btrfs_fs_info *fs_info;
2166         struct btrfs_root *root;
2167         struct btrfs_path *path;
2168         struct btrfs_key key;
2169         struct btrfs_root_item *root_item;
2170         struct btrfs_root_ref *rref;
2171         struct extent_buffer *leaf;
2172         unsigned long item_off;
2173         unsigned long item_len;
2174         int slot;
2175         int ret = 0;
2176
2177         path = btrfs_alloc_path();
2178         if (!path)
2179                 return -ENOMEM;
2180
2181         subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL);
2182         if (!subvol_info) {
2183                 btrfs_free_path(path);
2184                 return -ENOMEM;
2185         }
2186
2187         fs_info = BTRFS_I(inode)->root->fs_info;
2188
2189         /* Get root_item of inode's subvolume */
2190         key.objectid = btrfs_root_id(BTRFS_I(inode)->root);
2191         root = btrfs_get_fs_root(fs_info, key.objectid, true);
2192         if (IS_ERR(root)) {
2193                 ret = PTR_ERR(root);
2194                 goto out_free;
2195         }
2196         root_item = &root->root_item;
2197
2198         subvol_info->treeid = key.objectid;
2199
2200         subvol_info->generation = btrfs_root_generation(root_item);
2201         subvol_info->flags = btrfs_root_flags(root_item);
2202
2203         memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE);
2204         memcpy(subvol_info->parent_uuid, root_item->parent_uuid,
2205                                                     BTRFS_UUID_SIZE);
2206         memcpy(subvol_info->received_uuid, root_item->received_uuid,
2207                                                     BTRFS_UUID_SIZE);
2208
2209         subvol_info->ctransid = btrfs_root_ctransid(root_item);
2210         subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
2211         subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
2212
2213         subvol_info->otransid = btrfs_root_otransid(root_item);
2214         subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
2215         subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
2216
2217         subvol_info->stransid = btrfs_root_stransid(root_item);
2218         subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
2219         subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
2220
2221         subvol_info->rtransid = btrfs_root_rtransid(root_item);
2222         subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
2223         subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
2224
2225         if (key.objectid != BTRFS_FS_TREE_OBJECTID) {
2226                 /* Search root tree for ROOT_BACKREF of this subvolume */
2227                 key.type = BTRFS_ROOT_BACKREF_KEY;
2228                 key.offset = 0;
2229                 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2230                 if (ret < 0) {
2231                         goto out;
2232                 } else if (path->slots[0] >=
2233                            btrfs_header_nritems(path->nodes[0])) {
2234                         ret = btrfs_next_leaf(fs_info->tree_root, path);
2235                         if (ret < 0) {
2236                                 goto out;
2237                         } else if (ret > 0) {
2238                                 ret = -EUCLEAN;
2239                                 goto out;
2240                         }
2241                 }
2242
2243                 leaf = path->nodes[0];
2244                 slot = path->slots[0];
2245                 btrfs_item_key_to_cpu(leaf, &key, slot);
2246                 if (key.objectid == subvol_info->treeid &&
2247                     key.type == BTRFS_ROOT_BACKREF_KEY) {
2248                         subvol_info->parent_id = key.offset;
2249
2250                         rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2251                         subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref);
2252
2253                         item_off = btrfs_item_ptr_offset(leaf, slot)
2254                                         + sizeof(struct btrfs_root_ref);
2255                         item_len = btrfs_item_size(leaf, slot)
2256                                         - sizeof(struct btrfs_root_ref);
2257                         read_extent_buffer(leaf, subvol_info->name,
2258                                            item_off, item_len);
2259                 } else {
2260                         ret = -ENOENT;
2261                         goto out;
2262                 }
2263         }
2264
2265         btrfs_free_path(path);
2266         path = NULL;
2267         if (copy_to_user(argp, subvol_info, sizeof(*subvol_info)))
2268                 ret = -EFAULT;
2269
2270 out:
2271         btrfs_put_root(root);
2272 out_free:
2273         btrfs_free_path(path);
2274         kfree(subvol_info);
2275         return ret;
2276 }
2277
2278 /*
2279  * Return ROOT_REF information of the subvolume containing this inode
2280  * except the subvolume name.
2281  */
2282 static int btrfs_ioctl_get_subvol_rootref(struct btrfs_root *root,
2283                                           void __user *argp)
2284 {
2285         struct btrfs_ioctl_get_subvol_rootref_args *rootrefs;
2286         struct btrfs_root_ref *rref;
2287         struct btrfs_path *path;
2288         struct btrfs_key key;
2289         struct extent_buffer *leaf;
2290         u64 objectid;
2291         int slot;
2292         int ret;
2293         u8 found;
2294
2295         path = btrfs_alloc_path();
2296         if (!path)
2297                 return -ENOMEM;
2298
2299         rootrefs = memdup_user(argp, sizeof(*rootrefs));
2300         if (IS_ERR(rootrefs)) {
2301                 btrfs_free_path(path);
2302                 return PTR_ERR(rootrefs);
2303         }
2304
2305         objectid = btrfs_root_id(root);
2306         key.objectid = objectid;
2307         key.type = BTRFS_ROOT_REF_KEY;
2308         key.offset = rootrefs->min_treeid;
2309         found = 0;
2310
2311         root = root->fs_info->tree_root;
2312         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2313         if (ret < 0) {
2314                 goto out;
2315         } else if (path->slots[0] >=
2316                    btrfs_header_nritems(path->nodes[0])) {
2317                 ret = btrfs_next_leaf(root, path);
2318                 if (ret < 0) {
2319                         goto out;
2320                 } else if (ret > 0) {
2321                         ret = -EUCLEAN;
2322                         goto out;
2323                 }
2324         }
2325         while (1) {
2326                 leaf = path->nodes[0];
2327                 slot = path->slots[0];
2328
2329                 btrfs_item_key_to_cpu(leaf, &key, slot);
2330                 if (key.objectid != objectid || key.type != BTRFS_ROOT_REF_KEY) {
2331                         ret = 0;
2332                         goto out;
2333                 }
2334
2335                 if (found == BTRFS_MAX_ROOTREF_BUFFER_NUM) {
2336                         ret = -EOVERFLOW;
2337                         goto out;
2338                 }
2339
2340                 rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2341                 rootrefs->rootref[found].treeid = key.offset;
2342                 rootrefs->rootref[found].dirid =
2343                                   btrfs_root_ref_dirid(leaf, rref);
2344                 found++;
2345
2346                 ret = btrfs_next_item(root, path);
2347                 if (ret < 0) {
2348                         goto out;
2349                 } else if (ret > 0) {
2350                         ret = -EUCLEAN;
2351                         goto out;
2352                 }
2353         }
2354
2355 out:
2356         btrfs_free_path(path);
2357
2358         if (!ret || ret == -EOVERFLOW) {
2359                 rootrefs->num_items = found;
2360                 /* update min_treeid for next search */
2361                 if (found)
2362                         rootrefs->min_treeid =
2363                                 rootrefs->rootref[found - 1].treeid + 1;
2364                 if (copy_to_user(argp, rootrefs, sizeof(*rootrefs)))
2365                         ret = -EFAULT;
2366         }
2367
2368         kfree(rootrefs);
2369
2370         return ret;
2371 }
2372
2373 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2374                                              void __user *arg,
2375                                              bool destroy_v2)
2376 {
2377         struct dentry *parent = file->f_path.dentry;
2378         struct dentry *dentry;
2379         struct inode *dir = d_inode(parent);
2380         struct btrfs_fs_info *fs_info = inode_to_fs_info(dir);
2381         struct inode *inode;
2382         struct btrfs_root *root = BTRFS_I(dir)->root;
2383         struct btrfs_root *dest = NULL;
2384         struct btrfs_ioctl_vol_args *vol_args = NULL;
2385         struct btrfs_ioctl_vol_args_v2 *vol_args2 = NULL;
2386         struct mnt_idmap *idmap = file_mnt_idmap(file);
2387         char *subvol_name, *subvol_name_ptr = NULL;
2388         int subvol_namelen;
2389         int ret = 0;
2390         bool destroy_parent = false;
2391
2392         /* We don't support snapshots with extent tree v2 yet. */
2393         if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2394                 btrfs_err(fs_info,
2395                           "extent tree v2 doesn't support snapshot deletion yet");
2396                 return -EOPNOTSUPP;
2397         }
2398
2399         if (destroy_v2) {
2400                 vol_args2 = memdup_user(arg, sizeof(*vol_args2));
2401                 if (IS_ERR(vol_args2))
2402                         return PTR_ERR(vol_args2);
2403
2404                 if (vol_args2->flags & ~BTRFS_SUBVOL_DELETE_ARGS_MASK) {
2405                         ret = -EOPNOTSUPP;
2406                         goto out;
2407                 }
2408
2409                 /*
2410                  * If SPEC_BY_ID is not set, we are looking for the subvolume by
2411                  * name, same as v1 currently does.
2412                  */
2413                 if (!(vol_args2->flags & BTRFS_SUBVOL_SPEC_BY_ID)) {
2414                         ret = btrfs_check_ioctl_vol_args2_subvol_name(vol_args2);
2415                         if (ret < 0)
2416                                 goto out;
2417                         subvol_name = vol_args2->name;
2418
2419                         ret = mnt_want_write_file(file);
2420                         if (ret)
2421                                 goto out;
2422                 } else {
2423                         struct inode *old_dir;
2424
2425                         if (vol_args2->subvolid < BTRFS_FIRST_FREE_OBJECTID) {
2426                                 ret = -EINVAL;
2427                                 goto out;
2428                         }
2429
2430                         ret = mnt_want_write_file(file);
2431                         if (ret)
2432                                 goto out;
2433
2434                         dentry = btrfs_get_dentry(fs_info->sb,
2435                                         BTRFS_FIRST_FREE_OBJECTID,
2436                                         vol_args2->subvolid, 0);
2437                         if (IS_ERR(dentry)) {
2438                                 ret = PTR_ERR(dentry);
2439                                 goto out_drop_write;
2440                         }
2441
2442                         /*
2443                          * Change the default parent since the subvolume being
2444                          * deleted can be outside of the current mount point.
2445                          */
2446                         parent = btrfs_get_parent(dentry);
2447
2448                         /*
2449                          * At this point dentry->d_name can point to '/' if the
2450                          * subvolume we want to destroy is outsite of the
2451                          * current mount point, so we need to release the
2452                          * current dentry and execute the lookup to return a new
2453                          * one with ->d_name pointing to the
2454                          * <mount point>/subvol_name.
2455                          */
2456                         dput(dentry);
2457                         if (IS_ERR(parent)) {
2458                                 ret = PTR_ERR(parent);
2459                                 goto out_drop_write;
2460                         }
2461                         old_dir = dir;
2462                         dir = d_inode(parent);
2463
2464                         /*
2465                          * If v2 was used with SPEC_BY_ID, a new parent was
2466                          * allocated since the subvolume can be outside of the
2467                          * current mount point. Later on we need to release this
2468                          * new parent dentry.
2469                          */
2470                         destroy_parent = true;
2471
2472                         /*
2473                          * On idmapped mounts, deletion via subvolid is
2474                          * restricted to subvolumes that are immediate
2475                          * ancestors of the inode referenced by the file
2476                          * descriptor in the ioctl. Otherwise the idmapping
2477                          * could potentially be abused to delete subvolumes
2478                          * anywhere in the filesystem the user wouldn't be able
2479                          * to delete without an idmapped mount.
2480                          */
2481                         if (old_dir != dir && idmap != &nop_mnt_idmap) {
2482                                 ret = -EOPNOTSUPP;
2483                                 goto free_parent;
2484                         }
2485
2486                         subvol_name_ptr = btrfs_get_subvol_name_from_objectid(
2487                                                 fs_info, vol_args2->subvolid);
2488                         if (IS_ERR(subvol_name_ptr)) {
2489                                 ret = PTR_ERR(subvol_name_ptr);
2490                                 goto free_parent;
2491                         }
2492                         /* subvol_name_ptr is already nul terminated */
2493                         subvol_name = (char *)kbasename(subvol_name_ptr);
2494                 }
2495         } else {
2496                 vol_args = memdup_user(arg, sizeof(*vol_args));
2497                 if (IS_ERR(vol_args))
2498                         return PTR_ERR(vol_args);
2499
2500                 ret = btrfs_check_ioctl_vol_args_path(vol_args);
2501                 if (ret < 0)
2502                         goto out;
2503
2504                 subvol_name = vol_args->name;
2505
2506                 ret = mnt_want_write_file(file);
2507                 if (ret)
2508                         goto out;
2509         }
2510
2511         subvol_namelen = strlen(subvol_name);
2512
2513         if (strchr(subvol_name, '/') ||
2514             strncmp(subvol_name, "..", subvol_namelen) == 0) {
2515                 ret = -EINVAL;
2516                 goto free_subvol_name;
2517         }
2518
2519         if (!S_ISDIR(dir->i_mode)) {
2520                 ret = -ENOTDIR;
2521                 goto free_subvol_name;
2522         }
2523
2524         ret = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
2525         if (ret == -EINTR)
2526                 goto free_subvol_name;
2527         dentry = lookup_one(idmap, subvol_name, parent, subvol_namelen);
2528         if (IS_ERR(dentry)) {
2529                 ret = PTR_ERR(dentry);
2530                 goto out_unlock_dir;
2531         }
2532
2533         if (d_really_is_negative(dentry)) {
2534                 ret = -ENOENT;
2535                 goto out_dput;
2536         }
2537
2538         inode = d_inode(dentry);
2539         dest = BTRFS_I(inode)->root;
2540         if (!capable(CAP_SYS_ADMIN)) {
2541                 /*
2542                  * Regular user.  Only allow this with a special mount
2543                  * option, when the user has write+exec access to the
2544                  * subvol root, and when rmdir(2) would have been
2545                  * allowed.
2546                  *
2547                  * Note that this is _not_ check that the subvol is
2548                  * empty or doesn't contain data that we wouldn't
2549                  * otherwise be able to delete.
2550                  *
2551                  * Users who want to delete empty subvols should try
2552                  * rmdir(2).
2553                  */
2554                 ret = -EPERM;
2555                 if (!btrfs_test_opt(fs_info, USER_SUBVOL_RM_ALLOWED))
2556                         goto out_dput;
2557
2558                 /*
2559                  * Do not allow deletion if the parent dir is the same
2560                  * as the dir to be deleted.  That means the ioctl
2561                  * must be called on the dentry referencing the root
2562                  * of the subvol, not a random directory contained
2563                  * within it.
2564                  */
2565                 ret = -EINVAL;
2566                 if (root == dest)
2567                         goto out_dput;
2568
2569                 ret = inode_permission(idmap, inode, MAY_WRITE | MAY_EXEC);
2570                 if (ret)
2571                         goto out_dput;
2572         }
2573
2574         /* check if subvolume may be deleted by a user */
2575         ret = btrfs_may_delete(idmap, dir, dentry, 1);
2576         if (ret)
2577                 goto out_dput;
2578
2579         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2580                 ret = -EINVAL;
2581                 goto out_dput;
2582         }
2583
2584         btrfs_inode_lock(BTRFS_I(inode), 0);
2585         ret = btrfs_delete_subvolume(BTRFS_I(dir), dentry);
2586         btrfs_inode_unlock(BTRFS_I(inode), 0);
2587         if (!ret)
2588                 d_delete_notify(dir, dentry);
2589
2590 out_dput:
2591         dput(dentry);
2592 out_unlock_dir:
2593         btrfs_inode_unlock(BTRFS_I(dir), 0);
2594 free_subvol_name:
2595         kfree(subvol_name_ptr);
2596 free_parent:
2597         if (destroy_parent)
2598                 dput(parent);
2599 out_drop_write:
2600         mnt_drop_write_file(file);
2601 out:
2602         kfree(vol_args2);
2603         kfree(vol_args);
2604         return ret;
2605 }
2606
2607 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2608 {
2609         struct inode *inode = file_inode(file);
2610         struct btrfs_root *root = BTRFS_I(inode)->root;
2611         struct btrfs_ioctl_defrag_range_args range = {0};
2612         int ret;
2613
2614         ret = mnt_want_write_file(file);
2615         if (ret)
2616                 return ret;
2617
2618         if (btrfs_root_readonly(root)) {
2619                 ret = -EROFS;
2620                 goto out;
2621         }
2622
2623         switch (inode->i_mode & S_IFMT) {
2624         case S_IFDIR:
2625                 if (!capable(CAP_SYS_ADMIN)) {
2626                         ret = -EPERM;
2627                         goto out;
2628                 }
2629                 ret = btrfs_defrag_root(root);
2630                 break;
2631         case S_IFREG:
2632                 /*
2633                  * Note that this does not check the file descriptor for write
2634                  * access. This prevents defragmenting executables that are
2635                  * running and allows defrag on files open in read-only mode.
2636                  */
2637                 if (!capable(CAP_SYS_ADMIN) &&
2638                     inode_permission(&nop_mnt_idmap, inode, MAY_WRITE)) {
2639                         ret = -EPERM;
2640                         goto out;
2641                 }
2642
2643                 if (argp) {
2644                         if (copy_from_user(&range, argp, sizeof(range))) {
2645                                 ret = -EFAULT;
2646                                 goto out;
2647                         }
2648                         if (range.flags & ~BTRFS_DEFRAG_RANGE_FLAGS_SUPP) {
2649                                 ret = -EOPNOTSUPP;
2650                                 goto out;
2651                         }
2652                         /* compression requires us to start the IO */
2653                         if ((range.flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2654                                 range.flags |= BTRFS_DEFRAG_RANGE_START_IO;
2655                                 range.extent_thresh = (u32)-1;
2656                         }
2657                 } else {
2658                         /* the rest are all set to zero by kzalloc */
2659                         range.len = (u64)-1;
2660                 }
2661                 ret = btrfs_defrag_file(file_inode(file), &file->f_ra,
2662                                         &range, BTRFS_OLDEST_GENERATION, 0);
2663                 if (ret > 0)
2664                         ret = 0;
2665                 break;
2666         default:
2667                 ret = -EINVAL;
2668         }
2669 out:
2670         mnt_drop_write_file(file);
2671         return ret;
2672 }
2673
2674 static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
2675 {
2676         struct btrfs_ioctl_vol_args *vol_args;
2677         bool restore_op = false;
2678         int ret;
2679
2680         if (!capable(CAP_SYS_ADMIN))
2681                 return -EPERM;
2682
2683         if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2684                 btrfs_err(fs_info, "device add not supported on extent tree v2 yet");
2685                 return -EINVAL;
2686         }
2687
2688         if (fs_info->fs_devices->temp_fsid) {
2689                 btrfs_err(fs_info,
2690                           "device add not supported on cloned temp-fsid mount");
2691                 return -EINVAL;
2692         }
2693
2694         if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_ADD)) {
2695                 if (!btrfs_exclop_start_try_lock(fs_info, BTRFS_EXCLOP_DEV_ADD))
2696                         return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
2697
2698                 /*
2699                  * We can do the device add because we have a paused balanced,
2700                  * change the exclusive op type and remember we should bring
2701                  * back the paused balance
2702                  */
2703                 fs_info->exclusive_operation = BTRFS_EXCLOP_DEV_ADD;
2704                 btrfs_exclop_start_unlock(fs_info);
2705                 restore_op = true;
2706         }
2707
2708         vol_args = memdup_user(arg, sizeof(*vol_args));
2709         if (IS_ERR(vol_args)) {
2710                 ret = PTR_ERR(vol_args);
2711                 goto out;
2712         }
2713
2714         ret = btrfs_check_ioctl_vol_args_path(vol_args);
2715         if (ret < 0)
2716                 goto out_free;
2717
2718         ret = btrfs_init_new_device(fs_info, vol_args->name);
2719
2720         if (!ret)
2721                 btrfs_info(fs_info, "disk added %s", vol_args->name);
2722
2723 out_free:
2724         kfree(vol_args);
2725 out:
2726         if (restore_op)
2727                 btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);
2728         else
2729                 btrfs_exclop_finish(fs_info);
2730         return ret;
2731 }
2732
2733 static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
2734 {
2735         BTRFS_DEV_LOOKUP_ARGS(args);
2736         struct inode *inode = file_inode(file);
2737         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2738         struct btrfs_ioctl_vol_args_v2 *vol_args;
2739         struct file *bdev_file = NULL;
2740         int ret;
2741         bool cancel = false;
2742
2743         if (!capable(CAP_SYS_ADMIN))
2744                 return -EPERM;
2745
2746         vol_args = memdup_user(arg, sizeof(*vol_args));
2747         if (IS_ERR(vol_args))
2748                 return PTR_ERR(vol_args);
2749
2750         if (vol_args->flags & ~BTRFS_DEVICE_REMOVE_ARGS_MASK) {
2751                 ret = -EOPNOTSUPP;
2752                 goto out;
2753         }
2754
2755         ret = btrfs_check_ioctl_vol_args2_subvol_name(vol_args);
2756         if (ret < 0)
2757                 goto out;
2758
2759         if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
2760                 args.devid = vol_args->devid;
2761         } else if (!strcmp("cancel", vol_args->name)) {
2762                 cancel = true;
2763         } else {
2764                 ret = btrfs_get_dev_args_from_path(fs_info, &args, vol_args->name);
2765                 if (ret)
2766                         goto out;
2767         }
2768
2769         ret = mnt_want_write_file(file);
2770         if (ret)
2771                 goto out;
2772
2773         ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
2774                                            cancel);
2775         if (ret)
2776                 goto err_drop;
2777
2778         /* Exclusive operation is now claimed */
2779         ret = btrfs_rm_device(fs_info, &args, &bdev_file);
2780
2781         btrfs_exclop_finish(fs_info);
2782
2783         if (!ret) {
2784                 if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
2785                         btrfs_info(fs_info, "device deleted: id %llu",
2786                                         vol_args->devid);
2787                 else
2788                         btrfs_info(fs_info, "device deleted: %s",
2789                                         vol_args->name);
2790         }
2791 err_drop:
2792         mnt_drop_write_file(file);
2793         if (bdev_file)
2794                 fput(bdev_file);
2795 out:
2796         btrfs_put_dev_args_from_path(&args);
2797         kfree(vol_args);
2798         return ret;
2799 }
2800
2801 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
2802 {
2803         BTRFS_DEV_LOOKUP_ARGS(args);
2804         struct inode *inode = file_inode(file);
2805         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2806         struct btrfs_ioctl_vol_args *vol_args;
2807         struct file *bdev_file = NULL;
2808         int ret;
2809         bool cancel = false;
2810
2811         if (!capable(CAP_SYS_ADMIN))
2812                 return -EPERM;
2813
2814         vol_args = memdup_user(arg, sizeof(*vol_args));
2815         if (IS_ERR(vol_args))
2816                 return PTR_ERR(vol_args);
2817
2818         ret = btrfs_check_ioctl_vol_args_path(vol_args);
2819         if (ret < 0)
2820                 goto out_free;
2821
2822         if (!strcmp("cancel", vol_args->name)) {
2823                 cancel = true;
2824         } else {
2825                 ret = btrfs_get_dev_args_from_path(fs_info, &args, vol_args->name);
2826                 if (ret)
2827                         goto out;
2828         }
2829
2830         ret = mnt_want_write_file(file);
2831         if (ret)
2832                 goto out;
2833
2834         ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
2835                                            cancel);
2836         if (ret == 0) {
2837                 ret = btrfs_rm_device(fs_info, &args, &bdev_file);
2838                 if (!ret)
2839                         btrfs_info(fs_info, "disk deleted %s", vol_args->name);
2840                 btrfs_exclop_finish(fs_info);
2841         }
2842
2843         mnt_drop_write_file(file);
2844         if (bdev_file)
2845                 fput(bdev_file);
2846 out:
2847         btrfs_put_dev_args_from_path(&args);
2848 out_free:
2849         kfree(vol_args);
2850         return ret;
2851 }
2852
2853 static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info,
2854                                 void __user *arg)
2855 {
2856         struct btrfs_ioctl_fs_info_args *fi_args;
2857         struct btrfs_device *device;
2858         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2859         u64 flags_in;
2860         int ret = 0;
2861
2862         fi_args = memdup_user(arg, sizeof(*fi_args));
2863         if (IS_ERR(fi_args))
2864                 return PTR_ERR(fi_args);
2865
2866         flags_in = fi_args->flags;
2867         memset(fi_args, 0, sizeof(*fi_args));
2868
2869         rcu_read_lock();
2870         fi_args->num_devices = fs_devices->num_devices;
2871
2872         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
2873                 if (device->devid > fi_args->max_id)
2874                         fi_args->max_id = device->devid;
2875         }
2876         rcu_read_unlock();
2877
2878         memcpy(&fi_args->fsid, fs_devices->fsid, sizeof(fi_args->fsid));
2879         fi_args->nodesize = fs_info->nodesize;
2880         fi_args->sectorsize = fs_info->sectorsize;
2881         fi_args->clone_alignment = fs_info->sectorsize;
2882
2883         if (flags_in & BTRFS_FS_INFO_FLAG_CSUM_INFO) {
2884                 fi_args->csum_type = btrfs_super_csum_type(fs_info->super_copy);
2885                 fi_args->csum_size = btrfs_super_csum_size(fs_info->super_copy);
2886                 fi_args->flags |= BTRFS_FS_INFO_FLAG_CSUM_INFO;
2887         }
2888
2889         if (flags_in & BTRFS_FS_INFO_FLAG_GENERATION) {
2890                 fi_args->generation = btrfs_get_fs_generation(fs_info);
2891                 fi_args->flags |= BTRFS_FS_INFO_FLAG_GENERATION;
2892         }
2893
2894         if (flags_in & BTRFS_FS_INFO_FLAG_METADATA_UUID) {
2895                 memcpy(&fi_args->metadata_uuid, fs_devices->metadata_uuid,
2896                        sizeof(fi_args->metadata_uuid));
2897                 fi_args->flags |= BTRFS_FS_INFO_FLAG_METADATA_UUID;
2898         }
2899
2900         if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
2901                 ret = -EFAULT;
2902
2903         kfree(fi_args);
2904         return ret;
2905 }
2906
2907 static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
2908                                  void __user *arg)
2909 {
2910         BTRFS_DEV_LOOKUP_ARGS(args);
2911         struct btrfs_ioctl_dev_info_args *di_args;
2912         struct btrfs_device *dev;
2913         int ret = 0;
2914
2915         di_args = memdup_user(arg, sizeof(*di_args));
2916         if (IS_ERR(di_args))
2917                 return PTR_ERR(di_args);
2918
2919         args.devid = di_args->devid;
2920         if (!btrfs_is_empty_uuid(di_args->uuid))
2921                 args.uuid = di_args->uuid;
2922
2923         rcu_read_lock();
2924         dev = btrfs_find_device(fs_info->fs_devices, &args);
2925         if (!dev) {
2926                 ret = -ENODEV;
2927                 goto out;
2928         }
2929
2930         di_args->devid = dev->devid;
2931         di_args->bytes_used = btrfs_device_get_bytes_used(dev);
2932         di_args->total_bytes = btrfs_device_get_total_bytes(dev);
2933         memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2934         memcpy(di_args->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2935         if (dev->name)
2936                 strscpy(di_args->path, btrfs_dev_name(dev), sizeof(di_args->path));
2937         else
2938                 di_args->path[0] = '\0';
2939
2940 out:
2941         rcu_read_unlock();
2942         if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2943                 ret = -EFAULT;
2944
2945         kfree(di_args);
2946         return ret;
2947 }
2948
2949 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
2950 {
2951         struct inode *inode = file_inode(file);
2952         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2953         struct btrfs_root *root = BTRFS_I(inode)->root;
2954         struct btrfs_root *new_root;
2955         struct btrfs_dir_item *di;
2956         struct btrfs_trans_handle *trans;
2957         struct btrfs_path *path = NULL;
2958         struct btrfs_disk_key disk_key;
2959         struct fscrypt_str name = FSTR_INIT("default", 7);
2960         u64 objectid = 0;
2961         u64 dir_id;
2962         int ret;
2963
2964         if (!capable(CAP_SYS_ADMIN))
2965                 return -EPERM;
2966
2967         ret = mnt_want_write_file(file);
2968         if (ret)
2969                 return ret;
2970
2971         if (copy_from_user(&objectid, argp, sizeof(objectid))) {
2972                 ret = -EFAULT;
2973                 goto out;
2974         }
2975
2976         if (!objectid)
2977                 objectid = BTRFS_FS_TREE_OBJECTID;
2978
2979         new_root = btrfs_get_fs_root(fs_info, objectid, true);
2980         if (IS_ERR(new_root)) {
2981                 ret = PTR_ERR(new_root);
2982                 goto out;
2983         }
2984         if (!is_fstree(btrfs_root_id(new_root))) {
2985                 ret = -ENOENT;
2986                 goto out_free;
2987         }
2988
2989         path = btrfs_alloc_path();
2990         if (!path) {
2991                 ret = -ENOMEM;
2992                 goto out_free;
2993         }
2994
2995         trans = btrfs_start_transaction(root, 1);
2996         if (IS_ERR(trans)) {
2997                 ret = PTR_ERR(trans);
2998                 goto out_free;
2999         }
3000
3001         dir_id = btrfs_super_root_dir(fs_info->super_copy);
3002         di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
3003                                    dir_id, &name, 1);
3004         if (IS_ERR_OR_NULL(di)) {
3005                 btrfs_release_path(path);
3006                 btrfs_end_transaction(trans);
3007                 btrfs_err(fs_info,
3008                           "Umm, you don't have the default diritem, this isn't going to work");
3009                 ret = -ENOENT;
3010                 goto out_free;
3011         }
3012
3013         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
3014         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
3015         btrfs_mark_buffer_dirty(trans, path->nodes[0]);
3016         btrfs_release_path(path);
3017
3018         btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
3019         btrfs_end_transaction(trans);
3020 out_free:
3021         btrfs_put_root(new_root);
3022         btrfs_free_path(path);
3023 out:
3024         mnt_drop_write_file(file);
3025         return ret;
3026 }
3027
3028 static void get_block_group_info(struct list_head *groups_list,
3029                                  struct btrfs_ioctl_space_info *space)
3030 {
3031         struct btrfs_block_group *block_group;
3032
3033         space->total_bytes = 0;
3034         space->used_bytes = 0;
3035         space->flags = 0;
3036         list_for_each_entry(block_group, groups_list, list) {
3037                 space->flags = block_group->flags;
3038                 space->total_bytes += block_group->length;
3039                 space->used_bytes += block_group->used;
3040         }
3041 }
3042
3043 static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info,
3044                                    void __user *arg)
3045 {
3046         struct btrfs_ioctl_space_args space_args = { 0 };
3047         struct btrfs_ioctl_space_info space;
3048         struct btrfs_ioctl_space_info *dest;
3049         struct btrfs_ioctl_space_info *dest_orig;
3050         struct btrfs_ioctl_space_info __user *user_dest;
3051         struct btrfs_space_info *info;
3052         static const u64 types[] = {
3053                 BTRFS_BLOCK_GROUP_DATA,
3054                 BTRFS_BLOCK_GROUP_SYSTEM,
3055                 BTRFS_BLOCK_GROUP_METADATA,
3056                 BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA
3057         };
3058         int num_types = 4;
3059         int alloc_size;
3060         int ret = 0;
3061         u64 slot_count = 0;
3062         int i, c;
3063
3064         if (copy_from_user(&space_args,
3065                            (struct btrfs_ioctl_space_args __user *)arg,
3066                            sizeof(space_args)))
3067                 return -EFAULT;
3068
3069         for (i = 0; i < num_types; i++) {
3070                 struct btrfs_space_info *tmp;
3071
3072                 info = NULL;
3073                 list_for_each_entry(tmp, &fs_info->space_info, list) {
3074                         if (tmp->flags == types[i]) {
3075                                 info = tmp;
3076                                 break;
3077                         }
3078                 }
3079
3080                 if (!info)
3081                         continue;
3082
3083                 down_read(&info->groups_sem);
3084                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3085                         if (!list_empty(&info->block_groups[c]))
3086                                 slot_count++;
3087                 }
3088                 up_read(&info->groups_sem);
3089         }
3090
3091         /*
3092          * Global block reserve, exported as a space_info
3093          */
3094         slot_count++;
3095
3096         /* space_slots == 0 means they are asking for a count */
3097         if (space_args.space_slots == 0) {
3098                 space_args.total_spaces = slot_count;
3099                 goto out;
3100         }
3101
3102         slot_count = min_t(u64, space_args.space_slots, slot_count);
3103
3104         alloc_size = sizeof(*dest) * slot_count;
3105
3106         /* we generally have at most 6 or so space infos, one for each raid
3107          * level.  So, a whole page should be more than enough for everyone
3108          */
3109         if (alloc_size > PAGE_SIZE)
3110                 return -ENOMEM;
3111
3112         space_args.total_spaces = 0;
3113         dest = kmalloc(alloc_size, GFP_KERNEL);
3114         if (!dest)
3115                 return -ENOMEM;
3116         dest_orig = dest;
3117
3118         /* now we have a buffer to copy into */
3119         for (i = 0; i < num_types; i++) {
3120                 struct btrfs_space_info *tmp;
3121
3122                 if (!slot_count)
3123                         break;
3124
3125                 info = NULL;
3126                 list_for_each_entry(tmp, &fs_info->space_info, list) {
3127                         if (tmp->flags == types[i]) {
3128                                 info = tmp;
3129                                 break;
3130                         }
3131                 }
3132
3133                 if (!info)
3134                         continue;
3135                 down_read(&info->groups_sem);
3136                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3137                         if (!list_empty(&info->block_groups[c])) {
3138                                 get_block_group_info(&info->block_groups[c],
3139                                                      &space);
3140                                 memcpy(dest, &space, sizeof(space));
3141                                 dest++;
3142                                 space_args.total_spaces++;
3143                                 slot_count--;
3144                         }
3145                         if (!slot_count)
3146                                 break;
3147                 }
3148                 up_read(&info->groups_sem);
3149         }
3150
3151         /*
3152          * Add global block reserve
3153          */
3154         if (slot_count) {
3155                 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3156
3157                 spin_lock(&block_rsv->lock);
3158                 space.total_bytes = block_rsv->size;
3159                 space.used_bytes = block_rsv->size - block_rsv->reserved;
3160                 spin_unlock(&block_rsv->lock);
3161                 space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
3162                 memcpy(dest, &space, sizeof(space));
3163                 space_args.total_spaces++;
3164         }
3165
3166         user_dest = (struct btrfs_ioctl_space_info __user *)
3167                 (arg + sizeof(struct btrfs_ioctl_space_args));
3168
3169         if (copy_to_user(user_dest, dest_orig, alloc_size))
3170                 ret = -EFAULT;
3171
3172         kfree(dest_orig);
3173 out:
3174         if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
3175                 ret = -EFAULT;
3176
3177         return ret;
3178 }
3179
3180 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
3181                                             void __user *argp)
3182 {
3183         struct btrfs_trans_handle *trans;
3184         u64 transid;
3185
3186         /*
3187          * Start orphan cleanup here for the given root in case it hasn't been
3188          * started already by other means. Errors are handled in the other
3189          * functions during transaction commit.
3190          */
3191         btrfs_orphan_cleanup(root);
3192
3193         trans = btrfs_attach_transaction_barrier(root);
3194         if (IS_ERR(trans)) {
3195                 if (PTR_ERR(trans) != -ENOENT)
3196                         return PTR_ERR(trans);
3197
3198                 /* No running transaction, don't bother */
3199                 transid = btrfs_get_last_trans_committed(root->fs_info);
3200                 goto out;
3201         }
3202         transid = trans->transid;
3203         btrfs_commit_transaction_async(trans);
3204 out:
3205         if (argp)
3206                 if (copy_to_user(argp, &transid, sizeof(transid)))
3207                         return -EFAULT;
3208         return 0;
3209 }
3210
3211 static noinline long btrfs_ioctl_wait_sync(struct btrfs_fs_info *fs_info,
3212                                            void __user *argp)
3213 {
3214         /* By default wait for the current transaction. */
3215         u64 transid = 0;
3216
3217         if (argp)
3218                 if (copy_from_user(&transid, argp, sizeof(transid)))
3219                         return -EFAULT;
3220
3221         return btrfs_wait_for_commit(fs_info, transid);
3222 }
3223
3224 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
3225 {
3226         struct btrfs_fs_info *fs_info = inode_to_fs_info(file_inode(file));
3227         struct btrfs_ioctl_scrub_args *sa;
3228         int ret;
3229
3230         if (!capable(CAP_SYS_ADMIN))
3231                 return -EPERM;
3232
3233         if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
3234                 btrfs_err(fs_info, "scrub is not supported on extent tree v2 yet");
3235                 return -EINVAL;
3236         }
3237
3238         sa = memdup_user(arg, sizeof(*sa));
3239         if (IS_ERR(sa))
3240                 return PTR_ERR(sa);
3241
3242         if (sa->flags & ~BTRFS_SCRUB_SUPPORTED_FLAGS) {
3243                 ret = -EOPNOTSUPP;
3244                 goto out;
3245         }
3246
3247         if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
3248                 ret = mnt_want_write_file(file);
3249                 if (ret)
3250                         goto out;
3251         }
3252
3253         ret = btrfs_scrub_dev(fs_info, sa->devid, sa->start, sa->end,
3254                               &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
3255                               0);
3256
3257         /*
3258          * Copy scrub args to user space even if btrfs_scrub_dev() returned an
3259          * error. This is important as it allows user space to know how much
3260          * progress scrub has done. For example, if scrub is canceled we get
3261          * -ECANCELED from btrfs_scrub_dev() and return that error back to user
3262          * space. Later user space can inspect the progress from the structure
3263          * btrfs_ioctl_scrub_args and resume scrub from where it left off
3264          * previously (btrfs-progs does this).
3265          * If we fail to copy the btrfs_ioctl_scrub_args structure to user space
3266          * then return -EFAULT to signal the structure was not copied or it may
3267          * be corrupt and unreliable due to a partial copy.
3268          */
3269         if (copy_to_user(arg, sa, sizeof(*sa)))
3270                 ret = -EFAULT;
3271
3272         if (!(sa->flags & BTRFS_SCRUB_READONLY))
3273                 mnt_drop_write_file(file);
3274 out:
3275         kfree(sa);
3276         return ret;
3277 }
3278
3279 static long btrfs_ioctl_scrub_cancel(struct btrfs_fs_info *fs_info)
3280 {
3281         if (!capable(CAP_SYS_ADMIN))
3282                 return -EPERM;
3283
3284         return btrfs_scrub_cancel(fs_info);
3285 }
3286
3287 static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
3288                                        void __user *arg)
3289 {
3290         struct btrfs_ioctl_scrub_args *sa;
3291         int ret;
3292
3293         if (!capable(CAP_SYS_ADMIN))
3294                 return -EPERM;
3295
3296         sa = memdup_user(arg, sizeof(*sa));
3297         if (IS_ERR(sa))
3298                 return PTR_ERR(sa);
3299
3300         ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
3301
3302         if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
3303                 ret = -EFAULT;
3304
3305         kfree(sa);
3306         return ret;
3307 }
3308
3309 static long btrfs_ioctl_get_dev_stats(struct btrfs_fs_info *fs_info,
3310                                       void __user *arg)
3311 {
3312         struct btrfs_ioctl_get_dev_stats *sa;
3313         int ret;
3314
3315         sa = memdup_user(arg, sizeof(*sa));
3316         if (IS_ERR(sa))
3317                 return PTR_ERR(sa);
3318
3319         if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
3320                 kfree(sa);
3321                 return -EPERM;
3322         }
3323
3324         ret = btrfs_get_dev_stats(fs_info, sa);
3325
3326         if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
3327                 ret = -EFAULT;
3328
3329         kfree(sa);
3330         return ret;
3331 }
3332
3333 static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
3334                                     void __user *arg)
3335 {
3336         struct btrfs_ioctl_dev_replace_args *p;
3337         int ret;
3338
3339         if (!capable(CAP_SYS_ADMIN))
3340                 return -EPERM;
3341
3342         if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
3343                 btrfs_err(fs_info, "device replace not supported on extent tree v2 yet");
3344                 return -EINVAL;
3345         }
3346
3347         p = memdup_user(arg, sizeof(*p));
3348         if (IS_ERR(p))
3349                 return PTR_ERR(p);
3350
3351         switch (p->cmd) {
3352         case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
3353                 if (sb_rdonly(fs_info->sb)) {
3354                         ret = -EROFS;
3355                         goto out;
3356                 }
3357                 if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_REPLACE)) {
3358                         ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3359                 } else {
3360                         ret = btrfs_dev_replace_by_ioctl(fs_info, p);
3361                         btrfs_exclop_finish(fs_info);
3362                 }
3363                 break;
3364         case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
3365                 btrfs_dev_replace_status(fs_info, p);
3366                 ret = 0;
3367                 break;
3368         case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
3369                 p->result = btrfs_dev_replace_cancel(fs_info);
3370                 ret = 0;
3371                 break;
3372         default:
3373                 ret = -EINVAL;
3374                 break;
3375         }
3376
3377         if ((ret == 0 || ret == -ECANCELED) && copy_to_user(arg, p, sizeof(*p)))
3378                 ret = -EFAULT;
3379 out:
3380         kfree(p);
3381         return ret;
3382 }
3383
3384 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
3385 {
3386         int ret = 0;
3387         int i;
3388         u64 rel_ptr;
3389         int size;
3390         struct btrfs_ioctl_ino_path_args *ipa = NULL;
3391         struct inode_fs_paths *ipath = NULL;
3392         struct btrfs_path *path;
3393
3394         if (!capable(CAP_DAC_READ_SEARCH))
3395                 return -EPERM;
3396
3397         path = btrfs_alloc_path();
3398         if (!path) {
3399                 ret = -ENOMEM;
3400                 goto out;
3401         }
3402
3403         ipa = memdup_user(arg, sizeof(*ipa));
3404         if (IS_ERR(ipa)) {
3405                 ret = PTR_ERR(ipa);
3406                 ipa = NULL;
3407                 goto out;
3408         }
3409
3410         size = min_t(u32, ipa->size, 4096);
3411         ipath = init_ipath(size, root, path);
3412         if (IS_ERR(ipath)) {
3413                 ret = PTR_ERR(ipath);
3414                 ipath = NULL;
3415                 goto out;
3416         }
3417
3418         ret = paths_from_inode(ipa->inum, ipath);
3419         if (ret < 0)
3420                 goto out;
3421
3422         for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
3423                 rel_ptr = ipath->fspath->val[i] -
3424                           (u64)(unsigned long)ipath->fspath->val;
3425                 ipath->fspath->val[i] = rel_ptr;
3426         }
3427
3428         btrfs_free_path(path);
3429         path = NULL;
3430         ret = copy_to_user((void __user *)(unsigned long)ipa->fspath,
3431                            ipath->fspath, size);
3432         if (ret) {
3433                 ret = -EFAULT;
3434                 goto out;
3435         }
3436
3437 out:
3438         btrfs_free_path(path);
3439         free_ipath(ipath);
3440         kfree(ipa);
3441
3442         return ret;
3443 }
3444
3445 static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
3446                                         void __user *arg, int version)
3447 {
3448         int ret = 0;
3449         int size;
3450         struct btrfs_ioctl_logical_ino_args *loi;
3451         struct btrfs_data_container *inodes = NULL;
3452         struct btrfs_path *path = NULL;
3453         bool ignore_offset;
3454
3455         if (!capable(CAP_SYS_ADMIN))
3456                 return -EPERM;
3457
3458         loi = memdup_user(arg, sizeof(*loi));
3459         if (IS_ERR(loi))
3460                 return PTR_ERR(loi);
3461
3462         if (version == 1) {
3463                 ignore_offset = false;
3464                 size = min_t(u32, loi->size, SZ_64K);
3465         } else {
3466                 /* All reserved bits must be 0 for now */
3467                 if (memchr_inv(loi->reserved, 0, sizeof(loi->reserved))) {
3468                         ret = -EINVAL;
3469                         goto out_loi;
3470                 }
3471                 /* Only accept flags we have defined so far */
3472                 if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) {
3473                         ret = -EINVAL;
3474                         goto out_loi;
3475                 }
3476                 ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET;
3477                 size = min_t(u32, loi->size, SZ_16M);
3478         }
3479
3480         inodes = init_data_container(size);
3481         if (IS_ERR(inodes)) {
3482                 ret = PTR_ERR(inodes);
3483                 goto out_loi;
3484         }
3485
3486         path = btrfs_alloc_path();
3487         if (!path) {
3488                 ret = -ENOMEM;
3489                 goto out;
3490         }
3491         ret = iterate_inodes_from_logical(loi->logical, fs_info, path,
3492                                           inodes, ignore_offset);
3493         btrfs_free_path(path);
3494         if (ret == -EINVAL)
3495                 ret = -ENOENT;
3496         if (ret < 0)
3497                 goto out;
3498
3499         ret = copy_to_user((void __user *)(unsigned long)loi->inodes, inodes,
3500                            size);
3501         if (ret)
3502                 ret = -EFAULT;
3503
3504 out:
3505         kvfree(inodes);
3506 out_loi:
3507         kfree(loi);
3508
3509         return ret;
3510 }
3511
3512 void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
3513                                struct btrfs_ioctl_balance_args *bargs)
3514 {
3515         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3516
3517         bargs->flags = bctl->flags;
3518
3519         if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags))
3520                 bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
3521         if (atomic_read(&fs_info->balance_pause_req))
3522                 bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
3523         if (atomic_read(&fs_info->balance_cancel_req))
3524                 bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
3525
3526         memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
3527         memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
3528         memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
3529
3530         spin_lock(&fs_info->balance_lock);
3531         memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
3532         spin_unlock(&fs_info->balance_lock);
3533 }
3534
3535 /*
3536  * Try to acquire fs_info::balance_mutex as well as set BTRFS_EXLCOP_BALANCE as
3537  * required.
3538  *
3539  * @fs_info:       the filesystem
3540  * @excl_acquired: ptr to boolean value which is set to false in case balance
3541  *                 is being resumed
3542  *
3543  * Return 0 on success in which case both fs_info::balance is acquired as well
3544  * as exclusive ops are blocked. In case of failure return an error code.
3545  */
3546 static int btrfs_try_lock_balance(struct btrfs_fs_info *fs_info, bool *excl_acquired)
3547 {
3548         int ret;
3549
3550         /*
3551          * Exclusive operation is locked. Three possibilities:
3552          *   (1) some other op is running
3553          *   (2) balance is running
3554          *   (3) balance is paused -- special case (think resume)
3555          */
3556         while (1) {
3557                 if (btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {
3558                         *excl_acquired = true;
3559                         mutex_lock(&fs_info->balance_mutex);
3560                         return 0;
3561                 }
3562
3563                 mutex_lock(&fs_info->balance_mutex);
3564                 if (fs_info->balance_ctl) {
3565                         /* This is either (2) or (3) */
3566                         if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
3567                                 /* This is (2) */
3568                                 ret = -EINPROGRESS;
3569                                 goto out_failure;
3570
3571                         } else {
3572                                 mutex_unlock(&fs_info->balance_mutex);
3573                                 /*
3574                                  * Lock released to allow other waiters to
3575                                  * continue, we'll reexamine the status again.
3576                                  */
3577                                 mutex_lock(&fs_info->balance_mutex);
3578
3579                                 if (fs_info->balance_ctl &&
3580                                     !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
3581                                         /* This is (3) */
3582                                         *excl_acquired = false;
3583                                         return 0;
3584                                 }
3585                         }
3586                 } else {
3587                         /* This is (1) */
3588                         ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3589                         goto out_failure;
3590                 }
3591
3592                 mutex_unlock(&fs_info->balance_mutex);
3593         }
3594
3595 out_failure:
3596         mutex_unlock(&fs_info->balance_mutex);
3597         *excl_acquired = false;
3598         return ret;
3599 }
3600
3601 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
3602 {
3603         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
3604         struct btrfs_fs_info *fs_info = root->fs_info;
3605         struct btrfs_ioctl_balance_args *bargs;
3606         struct btrfs_balance_control *bctl;
3607         bool need_unlock = true;
3608         int ret;
3609
3610         if (!capable(CAP_SYS_ADMIN))
3611                 return -EPERM;
3612
3613         ret = mnt_want_write_file(file);
3614         if (ret)
3615                 return ret;
3616
3617         bargs = memdup_user(arg, sizeof(*bargs));
3618         if (IS_ERR(bargs)) {
3619                 ret = PTR_ERR(bargs);
3620                 bargs = NULL;
3621                 goto out;
3622         }
3623
3624         ret = btrfs_try_lock_balance(fs_info, &need_unlock);
3625         if (ret)
3626                 goto out;
3627
3628         lockdep_assert_held(&fs_info->balance_mutex);
3629
3630         if (bargs->flags & BTRFS_BALANCE_RESUME) {
3631                 if (!fs_info->balance_ctl) {
3632                         ret = -ENOTCONN;
3633                         goto out_unlock;
3634                 }
3635
3636                 bctl = fs_info->balance_ctl;
3637                 spin_lock(&fs_info->balance_lock);
3638                 bctl->flags |= BTRFS_BALANCE_RESUME;
3639                 spin_unlock(&fs_info->balance_lock);
3640                 btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE);
3641
3642                 goto do_balance;
3643         }
3644
3645         if (bargs->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
3646                 ret = -EINVAL;
3647                 goto out_unlock;
3648         }
3649
3650         if (fs_info->balance_ctl) {
3651                 ret = -EINPROGRESS;
3652                 goto out_unlock;
3653         }
3654
3655         bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
3656         if (!bctl) {
3657                 ret = -ENOMEM;
3658                 goto out_unlock;
3659         }
3660
3661         memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
3662         memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
3663         memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
3664
3665         bctl->flags = bargs->flags;
3666 do_balance:
3667         /*
3668          * Ownership of bctl and exclusive operation goes to btrfs_balance.
3669          * bctl is freed in reset_balance_state, or, if restriper was paused
3670          * all the way until unmount, in free_fs_info.  The flag should be
3671          * cleared after reset_balance_state.
3672          */
3673         need_unlock = false;
3674
3675         ret = btrfs_balance(fs_info, bctl, bargs);
3676         bctl = NULL;
3677
3678         if (ret == 0 || ret == -ECANCELED) {
3679                 if (copy_to_user(arg, bargs, sizeof(*bargs)))
3680                         ret = -EFAULT;
3681         }
3682
3683         kfree(bctl);
3684 out_unlock:
3685         mutex_unlock(&fs_info->balance_mutex);
3686         if (need_unlock)
3687                 btrfs_exclop_finish(fs_info);
3688 out:
3689         mnt_drop_write_file(file);
3690         kfree(bargs);
3691         return ret;
3692 }
3693
3694 static long btrfs_ioctl_balance_ctl(struct btrfs_fs_info *fs_info, int cmd)
3695 {
3696         if (!capable(CAP_SYS_ADMIN))
3697                 return -EPERM;
3698
3699         switch (cmd) {
3700         case BTRFS_BALANCE_CTL_PAUSE:
3701                 return btrfs_pause_balance(fs_info);
3702         case BTRFS_BALANCE_CTL_CANCEL:
3703                 return btrfs_cancel_balance(fs_info);
3704         }
3705
3706         return -EINVAL;
3707 }
3708
3709 static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
3710                                          void __user *arg)
3711 {
3712         struct btrfs_ioctl_balance_args *bargs;
3713         int ret = 0;
3714
3715         if (!capable(CAP_SYS_ADMIN))
3716                 return -EPERM;
3717
3718         mutex_lock(&fs_info->balance_mutex);
3719         if (!fs_info->balance_ctl) {
3720                 ret = -ENOTCONN;
3721                 goto out;
3722         }
3723
3724         bargs = kzalloc(sizeof(*bargs), GFP_KERNEL);
3725         if (!bargs) {
3726                 ret = -ENOMEM;
3727                 goto out;
3728         }
3729
3730         btrfs_update_ioctl_balance_args(fs_info, bargs);
3731
3732         if (copy_to_user(arg, bargs, sizeof(*bargs)))
3733                 ret = -EFAULT;
3734
3735         kfree(bargs);
3736 out:
3737         mutex_unlock(&fs_info->balance_mutex);
3738         return ret;
3739 }
3740
3741 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
3742 {
3743         struct inode *inode = file_inode(file);
3744         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
3745         struct btrfs_ioctl_quota_ctl_args *sa;
3746         int ret;
3747
3748         if (!capable(CAP_SYS_ADMIN))
3749                 return -EPERM;
3750
3751         ret = mnt_want_write_file(file);
3752         if (ret)
3753                 return ret;
3754
3755         sa = memdup_user(arg, sizeof(*sa));
3756         if (IS_ERR(sa)) {
3757                 ret = PTR_ERR(sa);
3758                 goto drop_write;
3759         }
3760
3761         switch (sa->cmd) {
3762         case BTRFS_QUOTA_CTL_ENABLE:
3763         case BTRFS_QUOTA_CTL_ENABLE_SIMPLE_QUOTA:
3764                 down_write(&fs_info->subvol_sem);
3765                 ret = btrfs_quota_enable(fs_info, sa);
3766                 up_write(&fs_info->subvol_sem);
3767                 break;
3768         case BTRFS_QUOTA_CTL_DISABLE:
3769                 /*
3770                  * Lock the cleaner mutex to prevent races with concurrent
3771                  * relocation, because relocation may be building backrefs for
3772                  * blocks of the quota root while we are deleting the root. This
3773                  * is like dropping fs roots of deleted snapshots/subvolumes, we
3774                  * need the same protection.
3775                  *
3776                  * This also prevents races between concurrent tasks trying to
3777                  * disable quotas, because we will unlock and relock
3778                  * qgroup_ioctl_lock across BTRFS_FS_QUOTA_ENABLED changes.
3779                  *
3780                  * We take this here because we have the dependency of
3781                  *
3782                  * inode_lock -> subvol_sem
3783                  *
3784                  * because of rename.  With relocation we can prealloc extents,
3785                  * so that makes the dependency chain
3786                  *
3787                  * cleaner_mutex -> inode_lock -> subvol_sem
3788                  *
3789                  * so we must take the cleaner_mutex here before we take the
3790                  * subvol_sem.  The deadlock can't actually happen, but this
3791                  * quiets lockdep.
3792                  */
3793                 mutex_lock(&fs_info->cleaner_mutex);
3794                 down_write(&fs_info->subvol_sem);
3795                 ret = btrfs_quota_disable(fs_info);
3796                 up_write(&fs_info->subvol_sem);
3797                 mutex_unlock(&fs_info->cleaner_mutex);
3798                 break;
3799         default:
3800                 ret = -EINVAL;
3801                 break;
3802         }
3803
3804         kfree(sa);
3805 drop_write:
3806         mnt_drop_write_file(file);
3807         return ret;
3808 }
3809
3810 /*
3811  * Quick check for ioctl handlers if quotas are enabled. Proper locking must be
3812  * done before any operations.
3813  */
3814 static bool qgroup_enabled(struct btrfs_fs_info *fs_info)
3815 {
3816         bool ret = true;
3817
3818         mutex_lock(&fs_info->qgroup_ioctl_lock);
3819         if (!fs_info->quota_root)
3820                 ret = false;
3821         mutex_unlock(&fs_info->qgroup_ioctl_lock);
3822
3823         return ret;
3824 }
3825
3826 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
3827 {
3828         struct inode *inode = file_inode(file);
3829         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
3830         struct btrfs_root *root = BTRFS_I(inode)->root;
3831         struct btrfs_ioctl_qgroup_assign_args *sa;
3832         struct btrfs_qgroup_list *prealloc = NULL;
3833         struct btrfs_trans_handle *trans;
3834         int ret;
3835         int err;
3836
3837         if (!capable(CAP_SYS_ADMIN))
3838                 return -EPERM;
3839
3840         if (!qgroup_enabled(root->fs_info))
3841                 return -ENOTCONN;
3842
3843         ret = mnt_want_write_file(file);
3844         if (ret)
3845                 return ret;
3846
3847         sa = memdup_user(arg, sizeof(*sa));
3848         if (IS_ERR(sa)) {
3849                 ret = PTR_ERR(sa);
3850                 goto drop_write;
3851         }
3852
3853         if (sa->assign) {
3854                 prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
3855                 if (!prealloc) {
3856                         ret = -ENOMEM;
3857                         goto drop_write;
3858                 }
3859         }
3860
3861         trans = btrfs_join_transaction(root);
3862         if (IS_ERR(trans)) {
3863                 ret = PTR_ERR(trans);
3864                 goto out;
3865         }
3866
3867         /*
3868          * Prealloc ownership is moved to the relation handler, there it's used
3869          * or freed on error.
3870          */
3871         if (sa->assign) {
3872                 ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc);
3873                 prealloc = NULL;
3874         } else {
3875                 ret = btrfs_del_qgroup_relation(trans, sa->src, sa->dst);
3876         }
3877
3878         /* update qgroup status and info */
3879         mutex_lock(&fs_info->qgroup_ioctl_lock);
3880         err = btrfs_run_qgroups(trans);
3881         mutex_unlock(&fs_info->qgroup_ioctl_lock);
3882         if (err < 0)
3883                 btrfs_warn(fs_info,
3884                            "qgroup status update failed after %s relation, marked as inconsistent",
3885                            sa->assign ? "adding" : "deleting");
3886         err = btrfs_end_transaction(trans);
3887         if (err && !ret)
3888                 ret = err;
3889
3890 out:
3891         kfree(prealloc);
3892         kfree(sa);
3893 drop_write:
3894         mnt_drop_write_file(file);
3895         return ret;
3896 }
3897
3898 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
3899 {
3900         struct inode *inode = file_inode(file);
3901         struct btrfs_root *root = BTRFS_I(inode)->root;
3902         struct btrfs_ioctl_qgroup_create_args *sa;
3903         struct btrfs_trans_handle *trans;
3904         int ret;
3905         int err;
3906
3907         if (!capable(CAP_SYS_ADMIN))
3908                 return -EPERM;
3909
3910         if (!qgroup_enabled(root->fs_info))
3911                 return -ENOTCONN;
3912
3913         ret = mnt_want_write_file(file);
3914         if (ret)
3915                 return ret;
3916
3917         sa = memdup_user(arg, sizeof(*sa));
3918         if (IS_ERR(sa)) {
3919                 ret = PTR_ERR(sa);
3920                 goto drop_write;
3921         }
3922
3923         if (!sa->qgroupid) {
3924                 ret = -EINVAL;
3925                 goto out;
3926         }
3927
3928         if (sa->create && is_fstree(sa->qgroupid)) {
3929                 ret = -EINVAL;
3930                 goto out;
3931         }
3932
3933         trans = btrfs_join_transaction(root);
3934         if (IS_ERR(trans)) {
3935                 ret = PTR_ERR(trans);
3936                 goto out;
3937         }
3938
3939         if (sa->create) {
3940                 ret = btrfs_create_qgroup(trans, sa->qgroupid);
3941         } else {
3942                 ret = btrfs_remove_qgroup(trans, sa->qgroupid);
3943         }
3944
3945         err = btrfs_end_transaction(trans);
3946         if (err && !ret)
3947                 ret = err;
3948
3949 out:
3950         kfree(sa);
3951 drop_write:
3952         mnt_drop_write_file(file);
3953         return ret;
3954 }
3955
3956 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
3957 {
3958         struct inode *inode = file_inode(file);
3959         struct btrfs_root *root = BTRFS_I(inode)->root;
3960         struct btrfs_ioctl_qgroup_limit_args *sa;
3961         struct btrfs_trans_handle *trans;
3962         int ret;
3963         int err;
3964         u64 qgroupid;
3965
3966         if (!capable(CAP_SYS_ADMIN))
3967                 return -EPERM;
3968
3969         if (!qgroup_enabled(root->fs_info))
3970                 return -ENOTCONN;
3971
3972         ret = mnt_want_write_file(file);
3973         if (ret)
3974                 return ret;
3975
3976         sa = memdup_user(arg, sizeof(*sa));
3977         if (IS_ERR(sa)) {
3978                 ret = PTR_ERR(sa);
3979                 goto drop_write;
3980         }
3981
3982         trans = btrfs_join_transaction(root);
3983         if (IS_ERR(trans)) {
3984                 ret = PTR_ERR(trans);
3985                 goto out;
3986         }
3987
3988         qgroupid = sa->qgroupid;
3989         if (!qgroupid) {
3990                 /* take the current subvol as qgroup */
3991                 qgroupid = btrfs_root_id(root);
3992         }
3993
3994         ret = btrfs_limit_qgroup(trans, qgroupid, &sa->lim);
3995
3996         err = btrfs_end_transaction(trans);
3997         if (err && !ret)
3998                 ret = err;
3999
4000 out:
4001         kfree(sa);
4002 drop_write:
4003         mnt_drop_write_file(file);
4004         return ret;
4005 }
4006
4007 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
4008 {
4009         struct inode *inode = file_inode(file);
4010         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4011         struct btrfs_ioctl_quota_rescan_args *qsa;
4012         int ret;
4013
4014         if (!capable(CAP_SYS_ADMIN))
4015                 return -EPERM;
4016
4017         if (!qgroup_enabled(fs_info))
4018                 return -ENOTCONN;
4019
4020         ret = mnt_want_write_file(file);
4021         if (ret)
4022                 return ret;
4023
4024         qsa = memdup_user(arg, sizeof(*qsa));
4025         if (IS_ERR(qsa)) {
4026                 ret = PTR_ERR(qsa);
4027                 goto drop_write;
4028         }
4029
4030         if (qsa->flags) {
4031                 ret = -EINVAL;
4032                 goto out;
4033         }
4034
4035         ret = btrfs_qgroup_rescan(fs_info);
4036
4037 out:
4038         kfree(qsa);
4039 drop_write:
4040         mnt_drop_write_file(file);
4041         return ret;
4042 }
4043
4044 static long btrfs_ioctl_quota_rescan_status(struct btrfs_fs_info *fs_info,
4045                                                 void __user *arg)
4046 {
4047         struct btrfs_ioctl_quota_rescan_args qsa = {0};
4048
4049         if (!capable(CAP_SYS_ADMIN))
4050                 return -EPERM;
4051
4052         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
4053                 qsa.flags = 1;
4054                 qsa.progress = fs_info->qgroup_rescan_progress.objectid;
4055         }
4056
4057         if (copy_to_user(arg, &qsa, sizeof(qsa)))
4058                 return -EFAULT;
4059
4060         return 0;
4061 }
4062
4063 static long btrfs_ioctl_quota_rescan_wait(struct btrfs_fs_info *fs_info,
4064                                                 void __user *arg)
4065 {
4066         if (!capable(CAP_SYS_ADMIN))
4067                 return -EPERM;
4068
4069         return btrfs_qgroup_wait_for_completion(fs_info, true);
4070 }
4071
4072 static long _btrfs_ioctl_set_received_subvol(struct file *file,
4073                                             struct mnt_idmap *idmap,
4074                                             struct btrfs_ioctl_received_subvol_args *sa)
4075 {
4076         struct inode *inode = file_inode(file);
4077         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4078         struct btrfs_root *root = BTRFS_I(inode)->root;
4079         struct btrfs_root_item *root_item = &root->root_item;
4080         struct btrfs_trans_handle *trans;
4081         struct timespec64 ct = current_time(inode);
4082         int ret = 0;
4083         int received_uuid_changed;
4084
4085         if (!inode_owner_or_capable(idmap, inode))
4086                 return -EPERM;
4087
4088         ret = mnt_want_write_file(file);
4089         if (ret < 0)
4090                 return ret;
4091
4092         down_write(&fs_info->subvol_sem);
4093
4094         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
4095                 ret = -EINVAL;
4096                 goto out;
4097         }
4098
4099         if (btrfs_root_readonly(root)) {
4100                 ret = -EROFS;
4101                 goto out;
4102         }
4103
4104         /*
4105          * 1 - root item
4106          * 2 - uuid items (received uuid + subvol uuid)
4107          */
4108         trans = btrfs_start_transaction(root, 3);
4109         if (IS_ERR(trans)) {
4110                 ret = PTR_ERR(trans);
4111                 trans = NULL;
4112                 goto out;
4113         }
4114
4115         sa->rtransid = trans->transid;
4116         sa->rtime.sec = ct.tv_sec;
4117         sa->rtime.nsec = ct.tv_nsec;
4118
4119         received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
4120                                        BTRFS_UUID_SIZE);
4121         if (received_uuid_changed &&
4122             !btrfs_is_empty_uuid(root_item->received_uuid)) {
4123                 ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid,
4124                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4125                                           btrfs_root_id(root));
4126                 if (ret && ret != -ENOENT) {
4127                         btrfs_abort_transaction(trans, ret);
4128                         btrfs_end_transaction(trans);
4129                         goto out;
4130                 }
4131         }
4132         memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
4133         btrfs_set_root_stransid(root_item, sa->stransid);
4134         btrfs_set_root_rtransid(root_item, sa->rtransid);
4135         btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
4136         btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
4137         btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
4138         btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
4139
4140         ret = btrfs_update_root(trans, fs_info->tree_root,
4141                                 &root->root_key, &root->root_item);
4142         if (ret < 0) {
4143                 btrfs_end_transaction(trans);
4144                 goto out;
4145         }
4146         if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
4147                 ret = btrfs_uuid_tree_add(trans, sa->uuid,
4148                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4149                                           btrfs_root_id(root));
4150                 if (ret < 0 && ret != -EEXIST) {
4151                         btrfs_abort_transaction(trans, ret);
4152                         btrfs_end_transaction(trans);
4153                         goto out;
4154                 }
4155         }
4156         ret = btrfs_commit_transaction(trans);
4157 out:
4158         up_write(&fs_info->subvol_sem);
4159         mnt_drop_write_file(file);
4160         return ret;
4161 }
4162
4163 #ifdef CONFIG_64BIT
4164 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
4165                                                 void __user *arg)
4166 {
4167         struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
4168         struct btrfs_ioctl_received_subvol_args *args64 = NULL;
4169         int ret = 0;
4170
4171         args32 = memdup_user(arg, sizeof(*args32));
4172         if (IS_ERR(args32))
4173                 return PTR_ERR(args32);
4174
4175         args64 = kmalloc(sizeof(*args64), GFP_KERNEL);
4176         if (!args64) {
4177                 ret = -ENOMEM;
4178                 goto out;
4179         }
4180
4181         memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
4182         args64->stransid = args32->stransid;
4183         args64->rtransid = args32->rtransid;
4184         args64->stime.sec = args32->stime.sec;
4185         args64->stime.nsec = args32->stime.nsec;
4186         args64->rtime.sec = args32->rtime.sec;
4187         args64->rtime.nsec = args32->rtime.nsec;
4188         args64->flags = args32->flags;
4189
4190         ret = _btrfs_ioctl_set_received_subvol(file, file_mnt_idmap(file), args64);
4191         if (ret)
4192                 goto out;
4193
4194         memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
4195         args32->stransid = args64->stransid;
4196         args32->rtransid = args64->rtransid;
4197         args32->stime.sec = args64->stime.sec;
4198         args32->stime.nsec = args64->stime.nsec;
4199         args32->rtime.sec = args64->rtime.sec;
4200         args32->rtime.nsec = args64->rtime.nsec;
4201         args32->flags = args64->flags;
4202
4203         ret = copy_to_user(arg, args32, sizeof(*args32));
4204         if (ret)
4205                 ret = -EFAULT;
4206
4207 out:
4208         kfree(args32);
4209         kfree(args64);
4210         return ret;
4211 }
4212 #endif
4213
4214 static long btrfs_ioctl_set_received_subvol(struct file *file,
4215                                             void __user *arg)
4216 {
4217         struct btrfs_ioctl_received_subvol_args *sa = NULL;
4218         int ret = 0;
4219
4220         sa = memdup_user(arg, sizeof(*sa));
4221         if (IS_ERR(sa))
4222                 return PTR_ERR(sa);
4223
4224         ret = _btrfs_ioctl_set_received_subvol(file, file_mnt_idmap(file), sa);
4225
4226         if (ret)
4227                 goto out;
4228
4229         ret = copy_to_user(arg, sa, sizeof(*sa));
4230         if (ret)
4231                 ret = -EFAULT;
4232
4233 out:
4234         kfree(sa);
4235         return ret;
4236 }
4237
4238 static int btrfs_ioctl_get_fslabel(struct btrfs_fs_info *fs_info,
4239                                         void __user *arg)
4240 {
4241         size_t len;
4242         int ret;
4243         char label[BTRFS_LABEL_SIZE];
4244
4245         spin_lock(&fs_info->super_lock);
4246         memcpy(label, fs_info->super_copy->label, BTRFS_LABEL_SIZE);
4247         spin_unlock(&fs_info->super_lock);
4248
4249         len = strnlen(label, BTRFS_LABEL_SIZE);
4250
4251         if (len == BTRFS_LABEL_SIZE) {
4252                 btrfs_warn(fs_info,
4253                            "label is too long, return the first %zu bytes",
4254                            --len);
4255         }
4256
4257         ret = copy_to_user(arg, label, len);
4258
4259         return ret ? -EFAULT : 0;
4260 }
4261
4262 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
4263 {
4264         struct inode *inode = file_inode(file);
4265         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4266         struct btrfs_root *root = BTRFS_I(inode)->root;
4267         struct btrfs_super_block *super_block = fs_info->super_copy;
4268         struct btrfs_trans_handle *trans;
4269         char label[BTRFS_LABEL_SIZE];
4270         int ret;
4271
4272         if (!capable(CAP_SYS_ADMIN))
4273                 return -EPERM;
4274
4275         if (copy_from_user(label, arg, sizeof(label)))
4276                 return -EFAULT;
4277
4278         if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
4279                 btrfs_err(fs_info,
4280                           "unable to set label with more than %d bytes",
4281                           BTRFS_LABEL_SIZE - 1);
4282                 return -EINVAL;
4283         }
4284
4285         ret = mnt_want_write_file(file);
4286         if (ret)
4287                 return ret;
4288
4289         trans = btrfs_start_transaction(root, 0);
4290         if (IS_ERR(trans)) {
4291                 ret = PTR_ERR(trans);
4292                 goto out_unlock;
4293         }
4294
4295         spin_lock(&fs_info->super_lock);
4296         strcpy(super_block->label, label);
4297         spin_unlock(&fs_info->super_lock);
4298         ret = btrfs_commit_transaction(trans);
4299
4300 out_unlock:
4301         mnt_drop_write_file(file);
4302         return ret;
4303 }
4304
4305 #define INIT_FEATURE_FLAGS(suffix) \
4306         { .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
4307           .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
4308           .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
4309
4310 int btrfs_ioctl_get_supported_features(void __user *arg)
4311 {
4312         static const struct btrfs_ioctl_feature_flags features[3] = {
4313                 INIT_FEATURE_FLAGS(SUPP),
4314                 INIT_FEATURE_FLAGS(SAFE_SET),
4315                 INIT_FEATURE_FLAGS(SAFE_CLEAR)
4316         };
4317
4318         if (copy_to_user(arg, &features, sizeof(features)))
4319                 return -EFAULT;
4320
4321         return 0;
4322 }
4323
4324 static int btrfs_ioctl_get_features(struct btrfs_fs_info *fs_info,
4325                                         void __user *arg)
4326 {
4327         struct btrfs_super_block *super_block = fs_info->super_copy;
4328         struct btrfs_ioctl_feature_flags features;
4329
4330         features.compat_flags = btrfs_super_compat_flags(super_block);
4331         features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
4332         features.incompat_flags = btrfs_super_incompat_flags(super_block);
4333
4334         if (copy_to_user(arg, &features, sizeof(features)))
4335                 return -EFAULT;
4336
4337         return 0;
4338 }
4339
4340 static int check_feature_bits(struct btrfs_fs_info *fs_info,
4341                               enum btrfs_feature_set set,
4342                               u64 change_mask, u64 flags, u64 supported_flags,
4343                               u64 safe_set, u64 safe_clear)
4344 {
4345         const char *type = btrfs_feature_set_name(set);
4346         char *names;
4347         u64 disallowed, unsupported;
4348         u64 set_mask = flags & change_mask;
4349         u64 clear_mask = ~flags & change_mask;
4350
4351         unsupported = set_mask & ~supported_flags;
4352         if (unsupported) {
4353                 names = btrfs_printable_features(set, unsupported);
4354                 if (names) {
4355                         btrfs_warn(fs_info,
4356                                    "this kernel does not support the %s feature bit%s",
4357                                    names, strchr(names, ',') ? "s" : "");
4358                         kfree(names);
4359                 } else
4360                         btrfs_warn(fs_info,
4361                                    "this kernel does not support %s bits 0x%llx",
4362                                    type, unsupported);
4363                 return -EOPNOTSUPP;
4364         }
4365
4366         disallowed = set_mask & ~safe_set;
4367         if (disallowed) {
4368                 names = btrfs_printable_features(set, disallowed);
4369                 if (names) {
4370                         btrfs_warn(fs_info,
4371                                    "can't set the %s feature bit%s while mounted",
4372                                    names, strchr(names, ',') ? "s" : "");
4373                         kfree(names);
4374                 } else
4375                         btrfs_warn(fs_info,
4376                                    "can't set %s bits 0x%llx while mounted",
4377                                    type, disallowed);
4378                 return -EPERM;
4379         }
4380
4381         disallowed = clear_mask & ~safe_clear;
4382         if (disallowed) {
4383                 names = btrfs_printable_features(set, disallowed);
4384                 if (names) {
4385                         btrfs_warn(fs_info,
4386                                    "can't clear the %s feature bit%s while mounted",
4387                                    names, strchr(names, ',') ? "s" : "");
4388                         kfree(names);
4389                 } else
4390                         btrfs_warn(fs_info,
4391                                    "can't clear %s bits 0x%llx while mounted",
4392                                    type, disallowed);
4393                 return -EPERM;
4394         }
4395
4396         return 0;
4397 }
4398
4399 #define check_feature(fs_info, change_mask, flags, mask_base)   \
4400 check_feature_bits(fs_info, FEAT_##mask_base, change_mask, flags,       \
4401                    BTRFS_FEATURE_ ## mask_base ## _SUPP,        \
4402                    BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,    \
4403                    BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
4404
4405 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
4406 {
4407         struct inode *inode = file_inode(file);
4408         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4409         struct btrfs_root *root = BTRFS_I(inode)->root;
4410         struct btrfs_super_block *super_block = fs_info->super_copy;
4411         struct btrfs_ioctl_feature_flags flags[2];
4412         struct btrfs_trans_handle *trans;
4413         u64 newflags;
4414         int ret;
4415
4416         if (!capable(CAP_SYS_ADMIN))
4417                 return -EPERM;
4418
4419         if (copy_from_user(flags, arg, sizeof(flags)))
4420                 return -EFAULT;
4421
4422         /* Nothing to do */
4423         if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
4424             !flags[0].incompat_flags)
4425                 return 0;
4426
4427         ret = check_feature(fs_info, flags[0].compat_flags,
4428                             flags[1].compat_flags, COMPAT);
4429         if (ret)
4430                 return ret;
4431
4432         ret = check_feature(fs_info, flags[0].compat_ro_flags,
4433                             flags[1].compat_ro_flags, COMPAT_RO);
4434         if (ret)
4435                 return ret;
4436
4437         ret = check_feature(fs_info, flags[0].incompat_flags,
4438                             flags[1].incompat_flags, INCOMPAT);
4439         if (ret)
4440                 return ret;
4441
4442         ret = mnt_want_write_file(file);
4443         if (ret)
4444                 return ret;
4445
4446         trans = btrfs_start_transaction(root, 0);
4447         if (IS_ERR(trans)) {
4448                 ret = PTR_ERR(trans);
4449                 goto out_drop_write;
4450         }
4451
4452         spin_lock(&fs_info->super_lock);
4453         newflags = btrfs_super_compat_flags(super_block);
4454         newflags |= flags[0].compat_flags & flags[1].compat_flags;
4455         newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
4456         btrfs_set_super_compat_flags(super_block, newflags);
4457
4458         newflags = btrfs_super_compat_ro_flags(super_block);
4459         newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
4460         newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
4461         btrfs_set_super_compat_ro_flags(super_block, newflags);
4462
4463         newflags = btrfs_super_incompat_flags(super_block);
4464         newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
4465         newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
4466         btrfs_set_super_incompat_flags(super_block, newflags);
4467         spin_unlock(&fs_info->super_lock);
4468
4469         ret = btrfs_commit_transaction(trans);
4470 out_drop_write:
4471         mnt_drop_write_file(file);
4472
4473         return ret;
4474 }
4475
4476 static int _btrfs_ioctl_send(struct btrfs_inode *inode, void __user *argp, bool compat)
4477 {
4478         struct btrfs_ioctl_send_args *arg;
4479         int ret;
4480
4481         if (compat) {
4482 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4483                 struct btrfs_ioctl_send_args_32 args32 = { 0 };
4484
4485                 ret = copy_from_user(&args32, argp, sizeof(args32));
4486                 if (ret)
4487                         return -EFAULT;
4488                 arg = kzalloc(sizeof(*arg), GFP_KERNEL);
4489                 if (!arg)
4490                         return -ENOMEM;
4491                 arg->send_fd = args32.send_fd;
4492                 arg->clone_sources_count = args32.clone_sources_count;
4493                 arg->clone_sources = compat_ptr(args32.clone_sources);
4494                 arg->parent_root = args32.parent_root;
4495                 arg->flags = args32.flags;
4496                 arg->version = args32.version;
4497                 memcpy(arg->reserved, args32.reserved,
4498                        sizeof(args32.reserved));
4499 #else
4500                 return -ENOTTY;
4501 #endif
4502         } else {
4503                 arg = memdup_user(argp, sizeof(*arg));
4504                 if (IS_ERR(arg))
4505                         return PTR_ERR(arg);
4506         }
4507         ret = btrfs_ioctl_send(inode, arg);
4508         kfree(arg);
4509         return ret;
4510 }
4511
4512 static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
4513                                     bool compat)
4514 {
4515         struct btrfs_ioctl_encoded_io_args args = { 0 };
4516         size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args,
4517                                              flags);
4518         size_t copy_end;
4519         struct iovec iovstack[UIO_FASTIOV];
4520         struct iovec *iov = iovstack;
4521         struct iov_iter iter;
4522         loff_t pos;
4523         struct kiocb kiocb;
4524         ssize_t ret;
4525
4526         if (!capable(CAP_SYS_ADMIN)) {
4527                 ret = -EPERM;
4528                 goto out_acct;
4529         }
4530
4531         if (compat) {
4532 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4533                 struct btrfs_ioctl_encoded_io_args_32 args32;
4534
4535                 copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32,
4536                                        flags);
4537                 if (copy_from_user(&args32, argp, copy_end)) {
4538                         ret = -EFAULT;
4539                         goto out_acct;
4540                 }
4541                 args.iov = compat_ptr(args32.iov);
4542                 args.iovcnt = args32.iovcnt;
4543                 args.offset = args32.offset;
4544                 args.flags = args32.flags;
4545 #else
4546                 return -ENOTTY;
4547 #endif
4548         } else {
4549                 copy_end = copy_end_kernel;
4550                 if (copy_from_user(&args, argp, copy_end)) {
4551                         ret = -EFAULT;
4552                         goto out_acct;
4553                 }
4554         }
4555         if (args.flags != 0) {
4556                 ret = -EINVAL;
4557                 goto out_acct;
4558         }
4559
4560         ret = import_iovec(ITER_DEST, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
4561                            &iov, &iter);
4562         if (ret < 0)
4563                 goto out_acct;
4564
4565         if (iov_iter_count(&iter) == 0) {
4566                 ret = 0;
4567                 goto out_iov;
4568         }
4569         pos = args.offset;
4570         ret = rw_verify_area(READ, file, &pos, args.len);
4571         if (ret < 0)
4572                 goto out_iov;
4573
4574         init_sync_kiocb(&kiocb, file);
4575         kiocb.ki_pos = pos;
4576
4577         ret = btrfs_encoded_read(&kiocb, &iter, &args);
4578         if (ret >= 0) {
4579                 fsnotify_access(file);
4580                 if (copy_to_user(argp + copy_end,
4581                                  (char *)&args + copy_end_kernel,
4582                                  sizeof(args) - copy_end_kernel))
4583                         ret = -EFAULT;
4584         }
4585
4586 out_iov:
4587         kfree(iov);
4588 out_acct:
4589         if (ret > 0)
4590                 add_rchar(current, ret);
4591         inc_syscr(current);
4592         return ret;
4593 }
4594
4595 static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp, bool compat)
4596 {
4597         struct btrfs_ioctl_encoded_io_args args;
4598         struct iovec iovstack[UIO_FASTIOV];
4599         struct iovec *iov = iovstack;
4600         struct iov_iter iter;
4601         loff_t pos;
4602         struct kiocb kiocb;
4603         ssize_t ret;
4604
4605         if (!capable(CAP_SYS_ADMIN)) {
4606                 ret = -EPERM;
4607                 goto out_acct;
4608         }
4609
4610         if (!(file->f_mode & FMODE_WRITE)) {
4611                 ret = -EBADF;
4612                 goto out_acct;
4613         }
4614
4615         if (compat) {
4616 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4617                 struct btrfs_ioctl_encoded_io_args_32 args32;
4618
4619                 if (copy_from_user(&args32, argp, sizeof(args32))) {
4620                         ret = -EFAULT;
4621                         goto out_acct;
4622                 }
4623                 args.iov = compat_ptr(args32.iov);
4624                 args.iovcnt = args32.iovcnt;
4625                 args.offset = args32.offset;
4626                 args.flags = args32.flags;
4627                 args.len = args32.len;
4628                 args.unencoded_len = args32.unencoded_len;
4629                 args.unencoded_offset = args32.unencoded_offset;
4630                 args.compression = args32.compression;
4631                 args.encryption = args32.encryption;
4632                 memcpy(args.reserved, args32.reserved, sizeof(args.reserved));
4633 #else
4634                 return -ENOTTY;
4635 #endif
4636         } else {
4637                 if (copy_from_user(&args, argp, sizeof(args))) {
4638                         ret = -EFAULT;
4639                         goto out_acct;
4640                 }
4641         }
4642
4643         ret = -EINVAL;
4644         if (args.flags != 0)
4645                 goto out_acct;
4646         if (memchr_inv(args.reserved, 0, sizeof(args.reserved)))
4647                 goto out_acct;
4648         if (args.compression == BTRFS_ENCODED_IO_COMPRESSION_NONE &&
4649             args.encryption == BTRFS_ENCODED_IO_ENCRYPTION_NONE)
4650                 goto out_acct;
4651         if (args.compression >= BTRFS_ENCODED_IO_COMPRESSION_TYPES ||
4652             args.encryption >= BTRFS_ENCODED_IO_ENCRYPTION_TYPES)
4653                 goto out_acct;
4654         if (args.unencoded_offset > args.unencoded_len)
4655                 goto out_acct;
4656         if (args.len > args.unencoded_len - args.unencoded_offset)
4657                 goto out_acct;
4658
4659         ret = import_iovec(ITER_SOURCE, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
4660                            &iov, &iter);
4661         if (ret < 0)
4662                 goto out_acct;
4663
4664         if (iov_iter_count(&iter) == 0) {
4665                 ret = 0;
4666                 goto out_iov;
4667         }
4668         pos = args.offset;
4669         ret = rw_verify_area(WRITE, file, &pos, args.len);
4670         if (ret < 0)
4671                 goto out_iov;
4672
4673         init_sync_kiocb(&kiocb, file);
4674         ret = kiocb_set_rw_flags(&kiocb, 0, WRITE);
4675         if (ret)
4676                 goto out_iov;
4677         kiocb.ki_pos = pos;
4678
4679         file_start_write(file);
4680
4681         ret = btrfs_do_write_iter(&kiocb, &iter, &args);
4682         if (ret > 0)
4683                 fsnotify_modify(file);
4684
4685         file_end_write(file);
4686 out_iov:
4687         kfree(iov);
4688 out_acct:
4689         if (ret > 0)
4690                 add_wchar(current, ret);
4691         inc_syscw(current);
4692         return ret;
4693 }
4694
4695 long btrfs_ioctl(struct file *file, unsigned int
4696                 cmd, unsigned long arg)
4697 {
4698         struct inode *inode = file_inode(file);
4699         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
4700         struct btrfs_root *root = BTRFS_I(inode)->root;
4701         void __user *argp = (void __user *)arg;
4702
4703         switch (cmd) {
4704         case FS_IOC_GETVERSION:
4705                 return btrfs_ioctl_getversion(inode, argp);
4706         case FS_IOC_GETFSLABEL:
4707                 return btrfs_ioctl_get_fslabel(fs_info, argp);
4708         case FS_IOC_SETFSLABEL:
4709                 return btrfs_ioctl_set_fslabel(file, argp);
4710         case FITRIM:
4711                 return btrfs_ioctl_fitrim(fs_info, argp);
4712         case BTRFS_IOC_SNAP_CREATE:
4713                 return btrfs_ioctl_snap_create(file, argp, 0);
4714         case BTRFS_IOC_SNAP_CREATE_V2:
4715                 return btrfs_ioctl_snap_create_v2(file, argp, 0);
4716         case BTRFS_IOC_SUBVOL_CREATE:
4717                 return btrfs_ioctl_snap_create(file, argp, 1);
4718         case BTRFS_IOC_SUBVOL_CREATE_V2:
4719                 return btrfs_ioctl_snap_create_v2(file, argp, 1);
4720         case BTRFS_IOC_SNAP_DESTROY:
4721                 return btrfs_ioctl_snap_destroy(file, argp, false);
4722         case BTRFS_IOC_SNAP_DESTROY_V2:
4723                 return btrfs_ioctl_snap_destroy(file, argp, true);
4724         case BTRFS_IOC_SUBVOL_GETFLAGS:
4725                 return btrfs_ioctl_subvol_getflags(inode, argp);
4726         case BTRFS_IOC_SUBVOL_SETFLAGS:
4727                 return btrfs_ioctl_subvol_setflags(file, argp);
4728         case BTRFS_IOC_DEFAULT_SUBVOL:
4729                 return btrfs_ioctl_default_subvol(file, argp);
4730         case BTRFS_IOC_DEFRAG:
4731                 return btrfs_ioctl_defrag(file, NULL);
4732         case BTRFS_IOC_DEFRAG_RANGE:
4733                 return btrfs_ioctl_defrag(file, argp);
4734         case BTRFS_IOC_RESIZE:
4735                 return btrfs_ioctl_resize(file, argp);
4736         case BTRFS_IOC_ADD_DEV:
4737                 return btrfs_ioctl_add_dev(fs_info, argp);
4738         case BTRFS_IOC_RM_DEV:
4739                 return btrfs_ioctl_rm_dev(file, argp);
4740         case BTRFS_IOC_RM_DEV_V2:
4741                 return btrfs_ioctl_rm_dev_v2(file, argp);
4742         case BTRFS_IOC_FS_INFO:
4743                 return btrfs_ioctl_fs_info(fs_info, argp);
4744         case BTRFS_IOC_DEV_INFO:
4745                 return btrfs_ioctl_dev_info(fs_info, argp);
4746         case BTRFS_IOC_TREE_SEARCH:
4747                 return btrfs_ioctl_tree_search(inode, argp);
4748         case BTRFS_IOC_TREE_SEARCH_V2:
4749                 return btrfs_ioctl_tree_search_v2(inode, argp);
4750         case BTRFS_IOC_INO_LOOKUP:
4751                 return btrfs_ioctl_ino_lookup(root, argp);
4752         case BTRFS_IOC_INO_PATHS:
4753                 return btrfs_ioctl_ino_to_path(root, argp);
4754         case BTRFS_IOC_LOGICAL_INO:
4755                 return btrfs_ioctl_logical_to_ino(fs_info, argp, 1);
4756         case BTRFS_IOC_LOGICAL_INO_V2:
4757                 return btrfs_ioctl_logical_to_ino(fs_info, argp, 2);
4758         case BTRFS_IOC_SPACE_INFO:
4759                 return btrfs_ioctl_space_info(fs_info, argp);
4760         case BTRFS_IOC_SYNC: {
4761                 int ret;
4762
4763                 ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
4764                 if (ret)
4765                         return ret;
4766                 ret = btrfs_sync_fs(inode->i_sb, 1);
4767                 /*
4768                  * The transaction thread may want to do more work,
4769                  * namely it pokes the cleaner kthread that will start
4770                  * processing uncleaned subvols.
4771                  */
4772                 wake_up_process(fs_info->transaction_kthread);
4773                 return ret;
4774         }
4775         case BTRFS_IOC_START_SYNC:
4776                 return btrfs_ioctl_start_sync(root, argp);
4777         case BTRFS_IOC_WAIT_SYNC:
4778                 return btrfs_ioctl_wait_sync(fs_info, argp);
4779         case BTRFS_IOC_SCRUB:
4780                 return btrfs_ioctl_scrub(file, argp);
4781         case BTRFS_IOC_SCRUB_CANCEL:
4782                 return btrfs_ioctl_scrub_cancel(fs_info);
4783         case BTRFS_IOC_SCRUB_PROGRESS:
4784                 return btrfs_ioctl_scrub_progress(fs_info, argp);
4785         case BTRFS_IOC_BALANCE_V2:
4786                 return btrfs_ioctl_balance(file, argp);
4787         case BTRFS_IOC_BALANCE_CTL:
4788                 return btrfs_ioctl_balance_ctl(fs_info, arg);
4789         case BTRFS_IOC_BALANCE_PROGRESS:
4790                 return btrfs_ioctl_balance_progress(fs_info, argp);
4791         case BTRFS_IOC_SET_RECEIVED_SUBVOL:
4792                 return btrfs_ioctl_set_received_subvol(file, argp);
4793 #ifdef CONFIG_64BIT
4794         case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
4795                 return btrfs_ioctl_set_received_subvol_32(file, argp);
4796 #endif
4797         case BTRFS_IOC_SEND:
4798                 return _btrfs_ioctl_send(BTRFS_I(inode), argp, false);
4799 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4800         case BTRFS_IOC_SEND_32:
4801                 return _btrfs_ioctl_send(BTRFS_I(inode), argp, true);
4802 #endif
4803         case BTRFS_IOC_GET_DEV_STATS:
4804                 return btrfs_ioctl_get_dev_stats(fs_info, argp);
4805         case BTRFS_IOC_QUOTA_CTL:
4806                 return btrfs_ioctl_quota_ctl(file, argp);
4807         case BTRFS_IOC_QGROUP_ASSIGN:
4808                 return btrfs_ioctl_qgroup_assign(file, argp);
4809         case BTRFS_IOC_QGROUP_CREATE:
4810                 return btrfs_ioctl_qgroup_create(file, argp);
4811         case BTRFS_IOC_QGROUP_LIMIT:
4812                 return btrfs_ioctl_qgroup_limit(file, argp);
4813         case BTRFS_IOC_QUOTA_RESCAN:
4814                 return btrfs_ioctl_quota_rescan(file, argp);
4815         case BTRFS_IOC_QUOTA_RESCAN_STATUS:
4816                 return btrfs_ioctl_quota_rescan_status(fs_info, argp);
4817         case BTRFS_IOC_QUOTA_RESCAN_WAIT:
4818                 return btrfs_ioctl_quota_rescan_wait(fs_info, argp);
4819         case BTRFS_IOC_DEV_REPLACE:
4820                 return btrfs_ioctl_dev_replace(fs_info, argp);
4821         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
4822                 return btrfs_ioctl_get_supported_features(argp);
4823         case BTRFS_IOC_GET_FEATURES:
4824                 return btrfs_ioctl_get_features(fs_info, argp);
4825         case BTRFS_IOC_SET_FEATURES:
4826                 return btrfs_ioctl_set_features(file, argp);
4827         case BTRFS_IOC_GET_SUBVOL_INFO:
4828                 return btrfs_ioctl_get_subvol_info(inode, argp);
4829         case BTRFS_IOC_GET_SUBVOL_ROOTREF:
4830                 return btrfs_ioctl_get_subvol_rootref(root, argp);
4831         case BTRFS_IOC_INO_LOOKUP_USER:
4832                 return btrfs_ioctl_ino_lookup_user(file, argp);
4833         case FS_IOC_ENABLE_VERITY:
4834                 return fsverity_ioctl_enable(file, (const void __user *)argp);
4835         case FS_IOC_MEASURE_VERITY:
4836                 return fsverity_ioctl_measure(file, argp);
4837         case BTRFS_IOC_ENCODED_READ:
4838                 return btrfs_ioctl_encoded_read(file, argp, false);
4839         case BTRFS_IOC_ENCODED_WRITE:
4840                 return btrfs_ioctl_encoded_write(file, argp, false);
4841 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
4842         case BTRFS_IOC_ENCODED_READ_32:
4843                 return btrfs_ioctl_encoded_read(file, argp, true);
4844         case BTRFS_IOC_ENCODED_WRITE_32:
4845                 return btrfs_ioctl_encoded_write(file, argp, true);
4846 #endif
4847         }
4848
4849         return -ENOTTY;
4850 }
4851
4852 #ifdef CONFIG_COMPAT
4853 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4854 {
4855         /*
4856          * These all access 32-bit values anyway so no further
4857          * handling is necessary.
4858          */
4859         switch (cmd) {
4860         case FS_IOC32_GETVERSION:
4861                 cmd = FS_IOC_GETVERSION;
4862                 break;
4863         }
4864
4865         return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
4866 }
4867 #endif