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