/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/kernel.h>
#include <linux/bio.h>
#include <linux/buffer_head.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mount.h>
#include <linux/mpage.h>
#include <linux/namei.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/bit_spinlock.h>
#include <linux/security.h>
#include <linux/xattr.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include "compat.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
#include "volumes.h"
#include "locking.h"

/* Mask out flags that are inappropriate for the given type of inode. */
static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
{
        if (S_ISDIR(mode))
                return flags;
        else if (S_ISREG(mode))
                return flags & ~FS_DIRSYNC_FL;
        else
                return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
}

/*
 * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
 */
static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
{
        unsigned int iflags = 0;

        if (flags & BTRFS_INODE_SYNC)
                iflags |= FS_SYNC_FL;
        if (flags & BTRFS_INODE_IMMUTABLE)
                iflags |= FS_IMMUTABLE_FL;
        if (flags & BTRFS_INODE_APPEND)
                iflags |= FS_APPEND_FL;
        if (flags & BTRFS_INODE_NODUMP)
                iflags |= FS_NODUMP_FL;
        if (flags & BTRFS_INODE_NOATIME)
                iflags |= FS_NOATIME_FL;
        if (flags & BTRFS_INODE_DIRSYNC)
                iflags |= FS_DIRSYNC_FL;

        return iflags;
}

/*
 * Update inode->i_flags based on the btrfs internal flags.
 */
void btrfs_update_iflags(struct inode *inode)
{
        struct btrfs_inode *ip = BTRFS_I(inode);

        inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);

        if (ip->flags & BTRFS_INODE_SYNC)
                inode->i_flags |= S_SYNC;
        if (ip->flags & BTRFS_INODE_IMMUTABLE)
                inode->i_flags |= S_IMMUTABLE;
        if (ip->flags & BTRFS_INODE_APPEND)
                inode->i_flags |= S_APPEND;
        if (ip->flags & BTRFS_INODE_NOATIME)
                inode->i_flags |= S_NOATIME;
        if (ip->flags & BTRFS_INODE_DIRSYNC)
                inode->i_flags |= S_DIRSYNC;
}

/*
 * Inherit flags from the parent inode.
 *
 * Unlike extN we don't have any flags we don't want to inherit currently.
 */
void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
{
        unsigned int flags;

        if (!dir)
                return;

        flags = BTRFS_I(dir)->flags;

        if (S_ISREG(inode->i_mode))
                flags &= ~BTRFS_INODE_DIRSYNC;
        else if (!S_ISDIR(inode->i_mode))
                flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);

        BTRFS_I(inode)->flags = flags;
        btrfs_update_iflags(inode);
}

static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
{
        struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
        unsigned int flags = btrfs_flags_to_ioctl(ip->flags);

        if (copy_to_user(arg, &flags, sizeof(flags)))
                return -EFAULT;
        return 0;
}

static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
{
        struct inode *inode = file->f_path.dentry->d_inode;
        struct btrfs_inode *ip = BTRFS_I(inode);
        struct btrfs_root *root = ip->root;
        struct btrfs_trans_handle *trans;
        unsigned int flags, oldflags;
        int ret;

        if (btrfs_root_readonly(root))
                return -EROFS;

        if (copy_from_user(&flags, arg, sizeof(flags)))
                return -EFAULT;

        if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
                      FS_NOATIME_FL | FS_NODUMP_FL | \
                      FS_SYNC_FL | FS_DIRSYNC_FL))
                return -EOPNOTSUPP;

        if (!is_owner_or_cap(inode))
                return -EACCES;

        mutex_lock(&inode->i_mutex);

        flags = btrfs_mask_flags(inode->i_mode, flags);
        oldflags = btrfs_flags_to_ioctl(ip->flags);
        if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
                if (!capable(CAP_LINUX_IMMUTABLE)) {
                        ret = -EPERM;
                        goto out_unlock;
                }
        }

        ret = mnt_want_write(file->f_path.mnt);
        if (ret)
                goto out_unlock;

        if (flags & FS_SYNC_FL)
                ip->flags |= BTRFS_INODE_SYNC;
        else
                ip->flags &= ~BTRFS_INODE_SYNC;
        if (flags & FS_IMMUTABLE_FL)
                ip->flags |= BTRFS_INODE_IMMUTABLE;
        else
                ip->flags &= ~BTRFS_INODE_IMMUTABLE;
        if (flags & FS_APPEND_FL)
                ip->flags |= BTRFS_INODE_APPEND;
        else
                ip->flags &= ~BTRFS_INODE_APPEND;
        if (flags & FS_NODUMP_FL)
                ip->flags |= BTRFS_INODE_NODUMP;
        else
                ip->flags &= ~BTRFS_INODE_NODUMP;
        if (flags & FS_NOATIME_FL)
                ip->flags |= BTRFS_INODE_NOATIME;
        else
                ip->flags &= ~BTRFS_INODE_NOATIME;
        if (flags & FS_DIRSYNC_FL)
                ip->flags |= BTRFS_INODE_DIRSYNC;
        else
                ip->flags &= ~BTRFS_INODE_DIRSYNC;


        trans = btrfs_join_transaction(root, 1);
        BUG_ON(IS_ERR(trans));

        ret = btrfs_update_inode(trans, root, inode);
        BUG_ON(ret);

        btrfs_update_iflags(inode);
        inode->i_ctime = CURRENT_TIME;
        btrfs_end_transaction(trans, root);

        mnt_drop_write(file->f_path.mnt);
 out_unlock:
        mutex_unlock(&inode->i_mutex);
        return 0;
}

static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
{
        struct inode *inode = file->f_path.dentry->d_inode;

        return put_user(inode->i_generation, arg);
}

static noinline int create_subvol(struct btrfs_root *root,
                                  struct dentry *dentry,
                                  char *name, int namelen,
                                  u64 *async_transid)
{
        struct btrfs_trans_handle *trans;
        struct btrfs_key key;
        struct btrfs_root_item root_item;
        struct btrfs_inode_item *inode_item;
        struct extent_buffer *leaf;
        struct btrfs_root *new_root;
        struct dentry *parent = dget_parent(dentry);
        struct inode *dir;
        int ret;
        int err;
        u64 objectid;
        u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
        u64 index = 0;

        ret = btrfs_find_free_objectid(NULL, root->fs_info->tree_root,
                                       0, &objectid);
        if (ret) {
                dput(parent);
                return ret;
        }

        dir = parent->d_inode;

        /*
         * 1 - inode item
         * 2 - refs
         * 1 - root item
         * 2 - dir items
         */
        trans = btrfs_start_transaction(root, 6);
        if (IS_ERR(trans)) {
                dput(parent);
                return PTR_ERR(trans);
        }

        leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
                                      0, objectid, NULL, 0, 0, 0);
        if (IS_ERR(leaf)) {
                ret = PTR_ERR(leaf);
                goto fail;
        }

        memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
        btrfs_set_header_bytenr(leaf, leaf->start);
        btrfs_set_header_generation(leaf, trans->transid);
        btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
        btrfs_set_header_owner(leaf, objectid);

        write_extent_buffer(leaf, root->fs_info->fsid,
                            (unsigned long)btrfs_header_fsid(leaf),
                            BTRFS_FSID_SIZE);
        write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
                            (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
                            BTRFS_UUID_SIZE);
        btrfs_mark_buffer_dirty(leaf);

        inode_item = &root_item.inode;
        memset(inode_item, 0, sizeof(*inode_item));
        inode_item->generation = cpu_to_le64(1);
        inode_item->size = cpu_to_le64(3);
        inode_item->nlink = cpu_to_le32(1);
        inode_item->nbytes = cpu_to_le64(root->leafsize);
        inode_item->mode = cpu_to_le32(S_IFDIR | 0755);

        btrfs_set_root_bytenr(&root_item, leaf->start);
        btrfs_set_root_generation(&root_item, trans->transid);
        btrfs_set_root_level(&root_item, 0);
        btrfs_set_root_refs(&root_item, 1);
        btrfs_set_root_used(&root_item, leaf->len);
        btrfs_set_root_last_snapshot(&root_item, 0);

        memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
        root_item.drop_level = 0;

        btrfs_tree_unlock(leaf);
        free_extent_buffer(leaf);
        leaf = NULL;

        btrfs_set_root_dirid(&root_item, new_dirid);

        key.objectid = objectid;
        key.offset = 0;
        btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
        ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
                                &root_item);
        if (ret)
                goto fail;

        key.offset = (u64)-1;
        new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
        BUG_ON(IS_ERR(new_root));

        btrfs_record_root_in_trans(trans, new_root);

        ret = btrfs_create_subvol_root(trans, new_root, new_dirid,
                                       BTRFS_I(dir)->block_group);
        /*
         * insert the directory item
         */
        ret = btrfs_set_inode_index(dir, &index);
        BUG_ON(ret);

        ret = btrfs_insert_dir_item(trans, root,
                                    name, namelen, dir->i_ino, &key,
                                    BTRFS_FT_DIR, index);
        if (ret)
                goto fail;

        btrfs_i_size_write(dir, dir->i_size + namelen * 2);
        ret = btrfs_update_inode(trans, root, dir);
        BUG_ON(ret);

        ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
                                 objectid, root->root_key.objectid,
                                 dir->i_ino, index, name, namelen);

        BUG_ON(ret);

        d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
fail:
        dput(parent);
        if (async_transid) {
                *async_transid = trans->transid;
                err = btrfs_commit_transaction_async(trans, root, 1);
        } else {
                err = btrfs_commit_transaction(trans, root);
        }
        if (err && !ret)
                ret = err;
        return ret;
}

static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
                           char *name, int namelen, u64 *async_transid,
                           bool readonly)
{
        struct inode *inode;
        struct dentry *parent;
        struct btrfs_pending_snapshot *pending_snapshot;
        struct btrfs_trans_handle *trans;
        int ret;

        if (!root->ref_cows)
                return -EINVAL;

        pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
        if (!pending_snapshot)
                return -ENOMEM;

        btrfs_init_block_rsv(&pending_snapshot->block_rsv);
        pending_snapshot->dentry = dentry;
        pending_snapshot->root = root;
        pending_snapshot->readonly = readonly;

        trans = btrfs_start_transaction(root->fs_info->extent_root, 5);
        if (IS_ERR(trans)) {
                ret = PTR_ERR(trans);
                goto fail;
        }

        ret = btrfs_snap_reserve_metadata(trans, pending_snapshot);
        BUG_ON(ret);

        list_add(&pending_snapshot->list,
                 &trans->transaction->pending_snapshots);
        if (async_transid) {
                *async_transid = trans->transid;
                ret = btrfs_commit_transaction_async(trans,
                                     root->fs_info->extent_root, 1);
        } else {
                ret = btrfs_commit_transaction(trans,
                                               root->fs_info->extent_root);
        }
        BUG_ON(ret);

        ret = pending_snapshot->error;
        if (ret)
                goto fail;

        btrfs_orphan_cleanup(pending_snapshot->snap);

        parent = dget_parent(dentry);
        inode = btrfs_lookup_dentry(parent->d_inode, dentry);
        dput(parent);
        if (IS_ERR(inode)) {
                ret = PTR_ERR(inode);
                goto fail;
        }
        BUG_ON(!inode);
        d_instantiate(dentry, inode);
        ret = 0;
fail:
        kfree(pending_snapshot);
        return ret;
}

/*  copy of check_sticky in fs/namei.c()
* It's inline, so penalty for filesystems that don't use sticky bit is
* minimal.
*/
static inline int btrfs_check_sticky(struct inode *dir, struct inode *inode)
{
        uid_t fsuid = current_fsuid();

        if (!(dir->i_mode & S_ISVTX))
                return 0;
        if (inode->i_uid == fsuid)
                return 0;
        if (dir->i_uid == fsuid)
                return 0;
        return !capable(CAP_FOWNER);
}

/*  copy of may_delete in fs/namei.c()
 *      Check whether we can remove a link victim from directory dir, check
 *  whether the type of victim is right.
 *  1. We can't do it if dir is read-only (done in permission())
 *  2. We should have write and exec permissions on dir
 *  3. We can't remove anything from append-only dir
 *  4. We can't do anything with immutable dir (done in permission())
 *  5. If the sticky bit on dir is set we should either
 *      a. be owner of dir, or
 *      b. be owner of victim, or
 *      c. have CAP_FOWNER capability
 *  6. If the victim is append-only or immutable we can't do antyhing with
 *     links pointing to it.
 *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
 *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
 *  9. We can't remove a root or mountpoint.
 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
 *     nfs_async_unlink().
 */

static int btrfs_may_delete(struct inode *dir,struct dentry *victim,int isdir)
{
        int error;

        if (!victim->d_inode)
                return -ENOENT;

        BUG_ON(victim->d_parent->d_inode != dir);
        audit_inode_child(victim, dir);

        error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
        if (error)
                return error;
        if (IS_APPEND(dir))
                return -EPERM;
        if (btrfs_check_sticky(dir, victim->d_inode)||
                IS_APPEND(victim->d_inode)||
            IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))
                return -EPERM;
        if (isdir) {
                if (!S_ISDIR(victim->d_inode->i_mode))
                        return -ENOTDIR;
                if (IS_ROOT(victim))
                        return -EBUSY;
        } else if (S_ISDIR(victim->d_inode->i_mode))
                return -EISDIR;
        if (IS_DEADDIR(dir))
                return -ENOENT;
        if (victim->d_flags & DCACHE_NFSFS_RENAMED)
                return -EBUSY;
        return 0;
}

/* copy of may_create in fs/namei.c() */
static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
{
        if (child->d_inode)
                return -EEXIST;
        if (IS_DEADDIR(dir))
                return -ENOENT;
        return inode_permission(dir, MAY_WRITE | MAY_EXEC);
}

/*
 * Create a new subvolume below @parent.  This is largely modeled after
 * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 * inside this filesystem so it's quite a bit simpler.
 */
static noinline int btrfs_mksubvol(struct path *parent,
                                   char *name, int namelen,
                                   struct btrfs_root *snap_src,
                                   u64 *async_transid, bool readonly)
{
        struct inode *dir  = parent->dentry->d_inode;
        struct dentry *dentry;
        int error;

        mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);

        dentry = lookup_one_len(name, parent->dentry, namelen);
        error = PTR_ERR(dentry);
        if (IS_ERR(dentry))
                goto out_unlock;

        error = -EEXIST;
        if (dentry->d_inode)
                goto out_dput;

        error = mnt_want_write(parent->mnt);
        if (error)
                goto out_dput;

        error = btrfs_may_create(dir, dentry);
        if (error)
                goto out_drop_write;

        down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);

        if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
                goto out_up_read;

        if (snap_src) {
                error = create_snapshot(snap_src, dentry,
                                        name, namelen, async_transid, readonly);
        } else {
                error = create_subvol(BTRFS_I(dir)->root, dentry,
                                      name, namelen, async_transid);
        }
        if (!error)
                fsnotify_mkdir(dir, dentry);
out_up_read:
        up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
out_drop_write:
        mnt_drop_write(parent->mnt);
out_dput:
        dput(dentry);
out_unlock:
        mutex_unlock(&dir->i_mutex);
        return error;
}

static int should_defrag_range(struct inode *inode, u64 start, u64 len,
                               int thresh, u64 *last_len, u64 *skip,
                               u64 *defrag_end)
{
        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
        struct extent_map *em = NULL;
        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
        int ret = 1;


        if (thresh == 0)
                thresh = 256 * 1024;

        /*
         * make sure that once we start defragging and extent, we keep on
         * defragging it
         */
        if (start < *defrag_end)
                return 1;

        *skip = 0;

        /*
         * hopefully we have this extent in the tree already, try without
         * the full extent lock
         */
        read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, start, len);
        read_unlock(&em_tree->lock);

        if (!em) {
                /* get the big lock and read metadata off disk */
                lock_extent(io_tree, start, start + len - 1, GFP_NOFS);
                em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
                unlock_extent(io_tree, start, start + len - 1, GFP_NOFS);

                if (IS_ERR(em))
                        return 0;
        }

        /* this will cover holes, and inline extents */
        if (em->block_start >= EXTENT_MAP_LAST_BYTE)
                ret = 0;

        /*
         * we hit a real extent, if it is big don't bother defragging it again
         */
        if ((*last_len == 0 || *last_len >= thresh) && em->len >= thresh)
                ret = 0;

        /*
         * last_len ends up being a counter of how many bytes we've defragged.
         * every time we choose not to defrag an extent, we reset *last_len
         * so that the next tiny extent will force a defrag.
         *
         * The end result of this is that tiny extents before a single big
         * extent will force at least part of that big extent to be defragged.
         */
        if (ret) {
                *last_len += len;
                *defrag_end = extent_map_end(em);
        } else {
                *last_len = 0;
                *skip = extent_map_end(em);
                *defrag_end = 0;
        }

        free_extent_map(em);
        return ret;
}

static int btrfs_defrag_file(struct file *file,
                             struct btrfs_ioctl_defrag_range_args *range)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
        struct btrfs_ordered_extent *ordered;
        struct page *page;
        struct btrfs_super_block *disk_super;
        unsigned long last_index;
        unsigned long ra_pages = root->fs_info->bdi.ra_pages;
        unsigned long total_read = 0;
        u64 features;
        u64 page_start;
        u64 page_end;
        u64 last_len = 0;
        u64 skip = 0;
        u64 defrag_end = 0;
        unsigned long i;
        int ret;
        int compress_type = BTRFS_COMPRESS_ZLIB;

        if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
                if (range->compress_type > BTRFS_COMPRESS_TYPES)
                        return -EINVAL;
                if (range->compress_type)
                        compress_type = range->compress_type;
        }

        if (inode->i_size == 0)
                return 0;

        if (range->start + range->len > range->start) {
                last_index = min_t(u64, inode->i_size - 1,
                         range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
        } else {
                last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
        }

        i = range->start >> PAGE_CACHE_SHIFT;
        while (i <= last_index) {
                if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
                                        PAGE_CACHE_SIZE,
                                        range->extent_thresh,
                                        &last_len, &skip,
                                        &defrag_end)) {
                        unsigned long next;
                        /*
                         * the should_defrag function tells us how much to skip
                         * bump our counter by the suggested amount
                         */
                        next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
                        i = max(i + 1, next);
                        continue;
                }

                if (total_read % ra_pages == 0) {
                        btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
                                       min(last_index, i + ra_pages - 1));
                }
                total_read++;
                mutex_lock(&inode->i_mutex);
                if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
                        BTRFS_I(inode)->force_compress = compress_type;

                ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
                if (ret)
                        goto err_unlock;
again:
                if (inode->i_size == 0 ||
                    i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) {
                        ret = 0;
                        goto err_reservations;
                }

                page = grab_cache_page(inode->i_mapping, i);
                if (!page) {
                        ret = -ENOMEM;
                        goto err_reservations;
                }

                if (!PageUptodate(page)) {
                        btrfs_readpage(NULL, page);
                        lock_page(page);
                        if (!PageUptodate(page)) {
                                unlock_page(page);
                                page_cache_release(page);
                                ret = -EIO;
                                goto err_reservations;
                        }
                }

                if (page->mapping != inode->i_mapping) {
                        unlock_page(page);
                        page_cache_release(page);
                        goto again;
                }

                wait_on_page_writeback(page);

                if (PageDirty(page)) {
                        btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
                        goto loop_unlock;
                }

                page_start = (u64)page->index << PAGE_CACHE_SHIFT;
                page_end = page_start + PAGE_CACHE_SIZE - 1;
                lock_extent(io_tree, page_start, page_end, GFP_NOFS);

                ordered = btrfs_lookup_ordered_extent(inode, page_start);
                if (ordered) {
                        unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
                        unlock_page(page);
                        page_cache_release(page);
                        btrfs_start_ordered_extent(inode, ordered, 1);
                        btrfs_put_ordered_extent(ordered);
                        goto again;
                }
                set_page_extent_mapped(page);

                /*
                 * this makes sure page_mkwrite is called on the
                 * page if it is dirtied again later
                 */
                clear_page_dirty_for_io(page);
                clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start,
                                  page_end, EXTENT_DIRTY | EXTENT_DELALLOC |
                                  EXTENT_DO_ACCOUNTING, GFP_NOFS);

                btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
                ClearPageChecked(page);
                set_page_dirty(page);
                unlock_extent(io_tree, page_start, page_end, GFP_NOFS);

loop_unlock:
                unlock_page(page);
                page_cache_release(page);
                mutex_unlock(&inode->i_mutex);

                balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
                i++;
        }

        if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO))
                filemap_flush(inode->i_mapping);

        if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
                /* the filemap_flush will queue IO into the worker threads, but
                 * we have to make sure the IO is actually started and that
                 * ordered extents get created before we return
                 */
                atomic_inc(&root->fs_info->async_submit_draining);
                while (atomic_read(&root->fs_info->nr_async_submits) ||
                      atomic_read(&root->fs_info->async_delalloc_pages)) {
                        wait_event(root->fs_info->async_submit_wait,
                           (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
                            atomic_read(&root->fs_info->async_delalloc_pages) == 0));
                }
                atomic_dec(&root->fs_info->async_submit_draining);

                mutex_lock(&inode->i_mutex);
                BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
                mutex_unlock(&inode->i_mutex);
        }

        disk_super = &root->fs_info->super_copy;
        features = btrfs_super_incompat_flags(disk_super);
        if (range->compress_type == BTRFS_COMPRESS_LZO) {
                features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
                btrfs_set_super_incompat_flags(disk_super, features);
        }

        return 0;

err_reservations:
        btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
err_unlock:
        mutex_unlock(&inode->i_mutex);
        return ret;
}

static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
                                        void __user *arg)
{
        u64 new_size;
        u64 old_size;
        u64 devid = 1;
        struct btrfs_ioctl_vol_args *vol_args;
        struct btrfs_trans_handle *trans;
        struct btrfs_device *device = NULL;
        char *sizestr;
        char *devstr = NULL;
        int ret = 0;
        int mod = 0;

        if (root->fs_info->sb->s_flags & MS_RDONLY)
                return -EROFS;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        vol_args = memdup_user(arg, sizeof(*vol_args));
        if (IS_ERR(vol_args))
                return PTR_ERR(vol_args);

        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';

        mutex_lock(&root->fs_info->volume_mutex);
        sizestr = vol_args->name;
        devstr = strchr(sizestr, ':');
        if (devstr) {
                char *end;
                sizestr = devstr + 1;
                *devstr = '\0';
                devstr = vol_args->name;
                devid = simple_strtoull(devstr, &end, 10);
                printk(KERN_INFO "resizing devid %llu\n",
                       (unsigned long long)devid);
        }
        device = btrfs_find_device(root, devid, NULL, NULL);
        if (!device) {
                printk(KERN_INFO "resizer unable to find device %llu\n",
                       (unsigned long long)devid);
                ret = -EINVAL;
                goto out_unlock;
        }
        if (!strcmp(sizestr, "max"))
                new_size = device->bdev->bd_inode->i_size;
        else {
                if (sizestr[0] == '-') {
                        mod = -1;
                        sizestr++;
                } else if (sizestr[0] == '+') {
                        mod = 1;
                        sizestr++;
                }
                new_size = memparse(sizestr, NULL);
                if (new_size == 0) {
                        ret = -EINVAL;
                        goto out_unlock;
                }
        }

        old_size = device->total_bytes;

        if (mod < 0) {
                if (new_size > old_size) {
                        ret = -EINVAL;
                        goto out_unlock;
                }
                new_size = old_size - new_size;
        } else if (mod > 0) {
                new_size = old_size + new_size;
        }

        if (new_size < 256 * 1024 * 1024) {
                ret = -EINVAL;
                goto out_unlock;
        }
        if (new_size > device->bdev->bd_inode->i_size) {
                ret = -EFBIG;
                goto out_unlock;
        }

        do_div(new_size, root->sectorsize);
        new_size *= root->sectorsize;

        printk(KERN_INFO "new size for %s is %llu\n",
                device->name, (unsigned long long)new_size);

        if (new_size > old_size) {
                trans = btrfs_start_transaction(root, 0);
                if (IS_ERR(trans)) {
                        ret = PTR_ERR(trans);
                        goto out_unlock;
                }
                ret = btrfs_grow_device(trans, device, new_size);
                btrfs_commit_transaction(trans, root);
        } else {
                ret = btrfs_shrink_device(device, new_size);
        }

out_unlock:
        mutex_unlock(&root->fs_info->volume_mutex);
        kfree(vol_args);
        return ret;
}

static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
                                                    char *name,
                                                    unsigned long fd,
                                                    int subvol,
                                                    u64 *transid,
                                                    bool readonly)
{
        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
        struct file *src_file;
        int namelen;
        int ret = 0;

        if (root->fs_info->sb->s_flags & MS_RDONLY)
                return -EROFS;

        namelen = strlen(name);
        if (strchr(name, '/')) {
                ret = -EINVAL;
                goto out;
        }

        if (subvol) {
                ret = btrfs_mksubvol(&file->f_path, name, namelen,
                                     NULL, transid, readonly);
        } else {
                struct inode *src_inode;
                src_file = fget(fd);
                if (!src_file) {
                        ret = -EINVAL;
                        goto out;
                }

                src_inode = src_file->f_path.dentry->d_inode;
                if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
                        printk(KERN_INFO "btrfs: Snapshot src from "
                               "another FS\n");
                        ret = -EINVAL;
                        fput(src_file);
                        goto out;
                }
                ret = btrfs_mksubvol(&file->f_path, name, namelen,
                                     BTRFS_I(src_inode)->root,
                                     transid, readonly);
                fput(src_file);
        }
out:
        return ret;
}

static noinline int btrfs_ioctl_snap_create(struct file *file,
                                            void __user *arg, int subvol)
{
        struct btrfs_ioctl_vol_args *vol_args;
        int ret;

        vol_args = memdup_user(arg, sizeof(*vol_args));
        if (IS_ERR(vol_args))
                return PTR_ERR(vol_args);
        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';

        ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
                                              vol_args->fd, subvol,
                                              NULL, false);

        kfree(vol_args);
        return ret;
}

static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
                                               void __user *arg, int subvol)
{
        struct btrfs_ioctl_vol_args_v2 *vol_args;
        int ret;
        u64 transid = 0;
        u64 *ptr = NULL;

        bool readonly = false;

        vol_args = memdup_user(arg, sizeof(*vol_args));
        if (IS_ERR(vol_args))
                return PTR_ERR(vol_args);
        vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';

        if (vol_args->flags &
            ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY)) {
                ret = -EOPNOTSUPP;
                goto out;
        }

        if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
                ptr = &transid;
        if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
                readonly = true;

        ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
                                              vol_args->fd, subvol,
                                              ptr, readonly);

        if (ret == 0 && ptr &&
            copy_to_user(arg +
                         offsetof(struct btrfs_ioctl_vol_args_v2,
                                  transid), ptr, sizeof(*ptr)))
                ret = -EFAULT;
out:
        kfree(vol_args);
        return ret;
}

static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
                                                void __user *arg)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        int ret = 0;
        u64 flags = 0;

        if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID)
                return -EINVAL;

        down_read(&root->fs_info->subvol_sem);
        if (btrfs_root_readonly(root))
                flags |= BTRFS_SUBVOL_RDONLY;
        up_read(&root->fs_info->subvol_sem);

        if (copy_to_user(arg, &flags, sizeof(flags)))
                ret = -EFAULT;

        return ret;
}

static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
                                              void __user *arg)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct btrfs_trans_handle *trans;
        u64 root_flags;
        u64 flags;
        int ret = 0;

        if (root->fs_info->sb->s_flags & MS_RDONLY)
                return -EROFS;

        if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID)
                return -EINVAL;

        if (copy_from_user(&flags, arg, sizeof(flags)))
                return -EFAULT;

        if (flags & BTRFS_SUBVOL_CREATE_ASYNC)
                return -EINVAL;

        if (flags & ~BTRFS_SUBVOL_RDONLY)
                return -EOPNOTSUPP;

        if (!is_owner_or_cap(inode))
                return -EACCES;

        down_write(&root->fs_info->subvol_sem);

        /* nothing to do */
        if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
                goto out;

        root_flags = btrfs_root_flags(&root->root_item);
        if (flags & BTRFS_SUBVOL_RDONLY)
                btrfs_set_root_flags(&root->root_item,
                                     root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
        else
                btrfs_set_root_flags(&root->root_item,
                                     root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);

        trans = btrfs_start_transaction(root, 1);
        if (IS_ERR(trans)) {
                ret = PTR_ERR(trans);
                goto out_reset;
        }

        ret = btrfs_update_root(trans, root->fs_info->tree_root,
                                &root->root_key, &root->root_item);

        btrfs_commit_transaction(trans, root);
out_reset:
        if (ret)
                btrfs_set_root_flags(&root->root_item, root_flags);
out:
        up_write(&root->fs_info->subvol_sem);
        return ret;
}

/*
 * helper to check if the subvolume references other subvolumes
 */
static noinline int may_destroy_subvol(struct btrfs_root *root)
{
        struct btrfs_path *path;
        struct btrfs_key key;
        int ret;

        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;

        key.objectid = root->root_key.objectid;
        key.type = BTRFS_ROOT_REF_KEY;
        key.offset = (u64)-1;

        ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
                                &key, path, 0, 0);
        if (ret < 0)
                goto out;
        BUG_ON(ret == 0);

        ret = 0;
        if (path->slots[0] > 0) {
                path->slots[0]--;
                btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
                if (key.objectid == root->root_key.objectid &&
                    key.type == BTRFS_ROOT_REF_KEY)
                        ret = -ENOTEMPTY;
        }
out:
        btrfs_free_path(path);
        return ret;
}

static noinline int key_in_sk(struct btrfs_key *key,
                              struct btrfs_ioctl_search_key *sk)
{
        struct btrfs_key test;
        int ret;

        test.objectid = sk->min_objectid;
        test.type = sk->min_type;
        test.offset = sk->min_offset;

        ret = btrfs_comp_cpu_keys(key, &test);
        if (ret < 0)
                return 0;

        test.objectid = sk->max_objectid;
        test.type = sk->max_type;
        test.offset = sk->max_offset;

        ret = btrfs_comp_cpu_keys(key, &test);
        if (ret > 0)
                return 0;
        return 1;
}

static noinline int copy_to_sk(struct btrfs_root *root,
                               struct btrfs_path *path,
                               struct btrfs_key *key,
                               struct btrfs_ioctl_search_key *sk,
                               char *buf,
                               unsigned long *sk_offset,
                               int *num_found)
{
        u64 found_transid;
        struct extent_buffer *leaf;
        struct btrfs_ioctl_search_header sh;
        unsigned long item_off;
        unsigned long item_len;
        int nritems;
        int i;
        int slot;
        int found = 0;
        int ret = 0;

        leaf = path->nodes[0];
        slot = path->slots[0];
        nritems = btrfs_header_nritems(leaf);

        if (btrfs_header_generation(leaf) > sk->max_transid) {
                i = nritems;
                goto advance_key;
        }
        found_transid = btrfs_header_generation(leaf);

        for (i = slot; i < nritems; i++) {
                item_off = btrfs_item_ptr_offset(leaf, i);
                item_len = btrfs_item_size_nr(leaf, i);

                if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
                        item_len = 0;

                if (sizeof(sh) + item_len + *sk_offset >
                    BTRFS_SEARCH_ARGS_BUFSIZE) {
                        ret = 1;
                        goto overflow;
                }

                btrfs_item_key_to_cpu(leaf, key, i);
                if (!key_in_sk(key, sk))
                        continue;

                sh.objectid = key->objectid;
                sh.offset = key->offset;
                sh.type = key->type;
                sh.len = item_len;
                sh.transid = found_transid;

                /* copy search result header */
                memcpy(buf + *sk_offset, &sh, sizeof(sh));
                *sk_offset += sizeof(sh);

                if (item_len) {
                        char *p = buf + *sk_offset;
                        /* copy the item */
                        read_extent_buffer(leaf, p,
                                           item_off, item_len);
                        *sk_offset += item_len;
                }
                found++;

                if (*num_found >= sk->nr_items)
                        break;
        }
advance_key:
        ret = 0;
        if (key->offset < (u64)-1 && key->offset < sk->max_offset)
                key->offset++;
        else if (key->type < (u8)-1 && key->type < sk->max_type) {
                key->offset = 0;
                key->type++;
        } else if (key->objectid < (u64)-1 && key->objectid < sk->max_objectid) {
                key->offset = 0;
                key->type = 0;
                key->objectid++;
        } else
                ret = 1;
overflow:
        *num_found += found;
        return ret;
}

static noinline int search_ioctl(struct inode *inode,
                                 struct btrfs_ioctl_search_args *args)
{
        struct btrfs_root *root;
        struct btrfs_key key;
        struct btrfs_key max_key;
        struct btrfs_path *path;
        struct btrfs_ioctl_search_key *sk = &args->key;
        struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
        int ret;
        int num_found = 0;
        unsigned long sk_offset = 0;

        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;

        if (sk->tree_id == 0) {
                /* search the root of the inode that was passed */
                root = BTRFS_I(inode)->root;
        } else {
                key.objectid = sk->tree_id;
                key.type = BTRFS_ROOT_ITEM_KEY;
                key.offset = (u64)-1;
                root = btrfs_read_fs_root_no_name(info, &key);
                if (IS_ERR(root)) {
                        printk(KERN_ERR "could not find root %llu\n",
                               sk->tree_id);
                        btrfs_free_path(path);
                        return -ENOENT;
                }
        }

        key.objectid = sk->min_objectid;
        key.type = sk->min_type;
        key.offset = sk->min_offset;

        max_key.objectid = sk->max_objectid;
        max_key.type = sk->max_type;
        max_key.offset = sk->max_offset;

        path->keep_locks = 1;

        while(1) {
                ret = btrfs_search_forward(root, &key, &max_key, path, 0,
                                           sk->min_transid);
                if (ret != 0) {
                        if (ret > 0)
                                ret = 0;
                        goto err;
                }
                ret = copy_to_sk(root, path, &key, sk, args->buf,
                                 &sk_offset, &num_found);
                btrfs_release_path(root, path);
                if (ret || num_found >= sk->nr_items)
                        break;

        }
        ret = 0;
err:
        sk->nr_items = num_found;
        btrfs_free_path(path);
        return ret;
}

static noinline int btrfs_ioctl_tree_search(struct file *file,
                                           void __user *argp)
{
         struct btrfs_ioctl_search_args *args;
         struct inode *inode;
         int ret;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        args = memdup_user(argp, sizeof(*args));
        if (IS_ERR(args))
                return PTR_ERR(args);

        inode = fdentry(file)->d_inode;
        ret = search_ioctl(inode, args);
        if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
                ret = -EFAULT;
        kfree(args);
        return ret;
}

/*
 * Search INODE_REFs to identify path name of 'dirid' directory
 * in a 'tree_id' tree. and sets path name to 'name'.
 */
static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
                                u64 tree_id, u64 dirid, char *name)
{
        struct btrfs_root *root;
        struct btrfs_key key;
        char *ptr;
        int ret = -1;
        int slot;
        int len;
        int total_len = 0;
        struct btrfs_inode_ref *iref;
        struct extent_buffer *l;
        struct btrfs_path *path;

        if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
                name[0]='\0';
                return 0;
        }

        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;

        ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];

        key.objectid = tree_id;
        key.type = BTRFS_ROOT_ITEM_KEY;
        key.offset = (u64)-1;
        root = btrfs_read_fs_root_no_name(info, &key);
        if (IS_ERR(root)) {
                printk(KERN_ERR "could not find root %llu\n", tree_id);
                ret = -ENOENT;
                goto out;
        }

        key.objectid = dirid;
        key.type = BTRFS_INODE_REF_KEY;
        key.offset = (u64)-1;

        while(1) {
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                if (ret < 0)
                        goto out;

                l = path->nodes[0];
                slot = path->slots[0];
                if (ret > 0 && slot > 0)
                        slot--;
                btrfs_item_key_to_cpu(l, &key, slot);

                if (ret > 0 && (key.objectid != dirid ||
                                key.type != BTRFS_INODE_REF_KEY)) {
                        ret = -ENOENT;
                        goto out;
                }

                iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
                len = btrfs_inode_ref_name_len(l, iref);
                ptr -= len + 1;
                total_len += len + 1;
                if (ptr < name)
                        goto out;

                *(ptr + len) = '/';
                read_extent_buffer(l, ptr,(unsigned long)(iref + 1), len);

                if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
                        break;

                btrfs_release_path(root, path);
                key.objectid = key.offset;
                key.offset = (u64)-1;
                dirid = key.objectid;

        }
        if (ptr < name)
                goto out;
        memcpy(name, ptr, total_len);
        name[total_len]='\0';
        ret = 0;
out:
        btrfs_free_path(path);
        return ret;
}

static noinline int btrfs_ioctl_ino_lookup(struct file *file,
                                           void __user *argp)
{
         struct btrfs_ioctl_ino_lookup_args *args;
         struct inode *inode;
         int ret;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        args = memdup_user(argp, sizeof(*args));
        if (IS_ERR(args))
                return PTR_ERR(args);

        inode = fdentry(file)->d_inode;

        if (args->treeid == 0)
                args->treeid = BTRFS_I(inode)->root->root_key.objectid;

        ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
                                        args->treeid, args->objectid,
                                        args->name);

        if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
                ret = -EFAULT;

        kfree(args);
        return ret;
}

static noinline int btrfs_ioctl_snap_destroy(struct file *file,
                                             void __user *arg)
{
        struct dentry *parent = fdentry(file);
        struct dentry *dentry;
        struct inode *dir = parent->d_inode;
        struct inode *inode;
        struct btrfs_root *root = BTRFS_I(dir)->root;
        struct btrfs_root *dest = NULL;
        struct btrfs_ioctl_vol_args *vol_args;
        struct btrfs_trans_handle *trans;
        int namelen;
        int ret;
        int err = 0;

        vol_args = memdup_user(arg, sizeof(*vol_args));
        if (IS_ERR(vol_args))
                return PTR_ERR(vol_args);

        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        namelen = strlen(vol_args->name);
        if (strchr(vol_args->name, '/') ||
            strncmp(vol_args->name, "..", namelen) == 0) {
                err = -EINVAL;
                goto out;
        }

        err = mnt_want_write(file->f_path.mnt);
        if (err)
                goto out;

        mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
        dentry = lookup_one_len(vol_args->name, parent, namelen);
        if (IS_ERR(dentry)) {
                err = PTR_ERR(dentry);
                goto out_unlock_dir;
        }

        if (!dentry->d_inode) {
                err = -ENOENT;
                goto out_dput;
        }

        inode = dentry->d_inode;
        dest = BTRFS_I(inode)->root;
        if (!capable(CAP_SYS_ADMIN)){
                /*
                 * Regular user.  Only allow this with a special mount
                 * option, when the user has write+exec access to the
                 * subvol root, and when rmdir(2) would have been
                 * allowed.
                 *
                 * Note that this is _not_ check that the subvol is
                 * empty or doesn't contain data that we wouldn't
                 * otherwise be able to delete.
                 *
                 * Users who want to delete empty subvols should try
                 * rmdir(2).
                 */
                err = -EPERM;
                if (!btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
                        goto out_dput;

                /*
                 * Do not allow deletion if the parent dir is the same
                 * as the dir to be deleted.  That means the ioctl
                 * must be called on the dentry referencing the root
                 * of the subvol, not a random directory contained
                 * within it.
                 */
                err = -EINVAL;
                if (root == dest)
                        goto out_dput;

                err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
                if (err)
                        goto out_dput;

                /* check if subvolume may be deleted by a non-root user */
                err = btrfs_may_delete(dir, dentry, 1);
                if (err)
                        goto out_dput;
        }

        if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
                err = -EINVAL;
                goto out_dput;
        }

        mutex_lock(&inode->i_mutex);
        err = d_invalidate(dentry);
        if (err)
                goto out_unlock;

        down_write(&root->fs_info->subvol_sem);

        err = may_destroy_subvol(dest);
        if (err)
                goto out_up_write;

        trans = btrfs_start_transaction(root, 0);
        if (IS_ERR(trans)) {
                err = PTR_ERR(trans);
                goto out_up_write;
        }
        trans->block_rsv = &root->fs_info->global_block_rsv;

        ret = btrfs_unlink_subvol(trans, root, dir,
                                dest->root_key.objectid,
                                dentry->d_name.name,
                                dentry->d_name.len);
        BUG_ON(ret);

        btrfs_record_root_in_trans(trans, dest);

        memset(&dest->root_item.drop_progress, 0,
                sizeof(dest->root_item.drop_progress));
        dest->root_item.drop_level = 0;
        btrfs_set_root_refs(&dest->root_item, 0);

        if (!xchg(&dest->orphan_item_inserted, 1)) {
                ret = btrfs_insert_orphan_item(trans,
                                        root->fs_info->tree_root,
                                        dest->root_key.objectid);
                BUG_ON(ret);
        }

        ret = btrfs_end_transaction(trans, root);
        BUG_ON(ret);
        inode->i_flags |= S_DEAD;
out_up_write:
        up_write(&root->fs_info->subvol_sem);
out_unlock:
        mutex_unlock(&inode->i_mutex);
        if (!err) {
                shrink_dcache_sb(root->fs_info->sb);
                btrfs_invalidate_inodes(dest);
                d_delete(dentry);
        }
out_dput:
        dput(dentry);
out_unlock_dir:
        mutex_unlock(&dir->i_mutex);
        mnt_drop_write(file->f_path.mnt);
out:
        kfree(vol_args);
        return err;
}

static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct btrfs_ioctl_defrag_range_args *range;
        int ret;

        if (btrfs_root_readonly(root))
                return -EROFS;

        ret = mnt_want_write(file->f_path.mnt);
        if (ret)
                return ret;

        switch (inode->i_mode & S_IFMT) {
        case S_IFDIR:
                if (!capable(CAP_SYS_ADMIN)) {
                        ret = -EPERM;
                        goto out;
                }
                ret = btrfs_defrag_root(root, 0);
                if (ret)
                        goto out;
                ret = btrfs_defrag_root(root->fs_info->extent_root, 0);
                break;
        case S_IFREG:
                if (!(file->f_mode & FMODE_WRITE)) {
                        ret = -EINVAL;
                        goto out;
                }

                range = kzalloc(sizeof(*range), GFP_KERNEL);
                if (!range) {
                        ret = -ENOMEM;
                        goto out;
                }

                if (argp) {
                        if (copy_from_user(range, argp,
                                           sizeof(*range))) {
                                ret = -EFAULT;
                                kfree(range);
                                goto out;
                        }
                        /* compression requires us to start the IO */
                        if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
                                range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
                                range->extent_thresh = (u32)-1;
                        }
                } else {
                        /* the rest are all set to zero by kzalloc */
                        range->len = (u64)-1;
                }
                ret = btrfs_defrag_file(file, range);
                kfree(range);
                break;
        default:
                ret = -EINVAL;
        }
out:
        mnt_drop_write(file->f_path.mnt);
        return ret;
}

static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
{
        struct btrfs_ioctl_vol_args *vol_args;
        int ret;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        vol_args = memdup_user(arg, sizeof(*vol_args));
        if (IS_ERR(vol_args))
                return PTR_ERR(vol_args);

        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        ret = btrfs_init_new_device(root, vol_args->name);

        kfree(vol_args);
        return ret;
}

static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
{
        struct btrfs_ioctl_vol_args *vol_args;
        int ret;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (root->fs_info->sb->s_flags & MS_RDONLY)
                return -EROFS;

        vol_args = memdup_user(arg, sizeof(*vol_args));
        if (IS_ERR(vol_args))
                return PTR_ERR(vol_args);

        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        ret = btrfs_rm_device(root, vol_args->name);

        kfree(vol_args);
        return ret;
}

static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                                       u64 off, u64 olen, u64 destoff)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct file *src_file;
        struct inode *src;
        struct btrfs_trans_handle *trans;
        struct btrfs_path *path;
        struct extent_buffer *leaf;
        char *buf;
        struct btrfs_key key;
        u32 nritems;
        int slot;
        int ret;
        u64 len = olen;
        u64 bs = root->fs_info->sb->s_blocksize;
        u64 hint_byte;

        /*
         * TODO:
         * - split compressed inline extents.  annoying: we need to
         *   decompress into destination's address_space (the file offset
         *   may change, so source mapping won't do), then recompress (or
         *   otherwise reinsert) a subrange.
         * - allow ranges within the same file to be cloned (provided
         *   they don't overlap)?
         */

        /* the destination must be opened for writing */
        if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
                return -EINVAL;

        if (btrfs_root_readonly(root))
                return -EROFS;

        ret = mnt_want_write(file->f_path.mnt);
        if (ret)
                return ret;

        src_file = fget(srcfd);
        if (!src_file) {
                ret = -EBADF;
                goto out_drop_write;
        }

        src = src_file->f_dentry->d_inode;

        ret = -EINVAL;
        if (src == inode)
                goto out_fput;

        /* the src must be open for reading */
        if (!(src_file->f_mode & FMODE_READ))
                goto out_fput;

        ret = -EISDIR;
        if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
                goto out_fput;

        ret = -EXDEV;
        if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
                goto out_fput;

        ret = -ENOMEM;
        buf = vmalloc(btrfs_level_size(root, 0));
        if (!buf)
                goto out_fput;

        path = btrfs_alloc_path();
        if (!path) {
                vfree(buf);
                goto out_fput;
        }
        path->reada = 2;

        if (inode < src) {
                mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
                mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
        } else {
                mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
                mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
        }

        /* determine range to clone */
        ret = -EINVAL;
        if (off + len > src->i_size || off + len < off)
                goto out_unlock;
        if (len == 0)
                olen = len = src->i_size - off;
        /* if we extend to eof, continue to block boundary */
        if (off + len == src->i_size)
                len = ALIGN(src->i_size, bs) - off;

        /* verify the end result is block aligned */
        if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
            !IS_ALIGNED(destoff, bs))
                goto out_unlock;

        /* do any pending delalloc/csum calc on src, one way or
           another, and lock file content */
        while (1) {
                struct btrfs_ordered_extent *ordered;
                lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
                ordered = btrfs_lookup_first_ordered_extent(src, off+len);
                if (!ordered &&
                    !test_range_bit(&BTRFS_I(src)->io_tree, off, off+len,
                                   EXTENT_DELALLOC, 0, NULL))
                        break;
                unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
                if (ordered)
                        btrfs_put_ordered_extent(ordered);
                btrfs_wait_ordered_range(src, off, len);
        }

        /* clone data */
        key.objectid = src->i_ino;
        key.type = BTRFS_EXTENT_DATA_KEY;
        key.offset = 0;

        while (1) {
                /*
                 * note the key will change type as we walk through the
                 * tree.
                 */
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                if (ret < 0)
                        goto out;

                nritems = btrfs_header_nritems(path->nodes[0]);
                if (path->slots[0] >= nritems) {
                        ret = btrfs_next_leaf(root, path);
                        if (ret < 0)
                                goto out;
                        if (ret > 0)
                                break;
                        nritems = btrfs_header_nritems(path->nodes[0]);
                }
                leaf = path->nodes[0];
                slot = path->slots[0];

                btrfs_item_key_to_cpu(leaf, &key, slot);
                if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
                    key.objectid != src->i_ino)
                        break;

                if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
                        struct btrfs_file_extent_item *extent;
                        int type;
                        u32 size;
                        struct btrfs_key new_key;
                        u64 disko = 0, diskl = 0;
                        u64 datao = 0, datal = 0;
                        u8 comp;
                        u64 endoff;

                        size = btrfs_item_size_nr(leaf, slot);
                        read_extent_buffer(leaf, buf,
                                           btrfs_item_ptr_offset(leaf, slot),
                                           size);

                        extent = btrfs_item_ptr(leaf, slot,
                                                struct btrfs_file_extent_item);
                        comp = btrfs_file_extent_compression(leaf, extent);
                        type = btrfs_file_extent_type(leaf, extent);
                        if (type == BTRFS_FILE_EXTENT_REG ||
                            type == BTRFS_FILE_EXTENT_PREALLOC) {
                                disko = btrfs_file_extent_disk_bytenr(leaf,
                                                                      extent);
                                diskl = btrfs_file_extent_disk_num_bytes(leaf,
                                                                 extent);
                                datao = btrfs_file_extent_offset(leaf, extent);
                                datal = btrfs_file_extent_num_bytes(leaf,
                                                                    extent);
                        } else if (type == BTRFS_FILE_EXTENT_INLINE) {
                                /* take upper bound, may be compressed */
                                datal = btrfs_file_extent_ram_bytes(leaf,
                                                                    extent);
                        }
                        btrfs_release_path(root, path);

                        if (key.offset + datal <= off ||
                            key.offset >= off+len)
                                goto next;

                        memcpy(&new_key, &key, sizeof(new_key));
                        new_key.objectid = inode->i_ino;
                        if (off <= key.offset)
                                new_key.offset = key.offset + destoff - off;
                        else
                                new_key.offset = destoff;

                        trans = btrfs_start_transaction(root, 1);
                        if (IS_ERR(trans)) {
                                ret = PTR_ERR(trans);
                                goto out;
                        }

                        if (type == BTRFS_FILE_EXTENT_REG ||
                            type == BTRFS_FILE_EXTENT_PREALLOC) {
                                if (off > key.offset) {
                                        datao += off - key.offset;
                                        datal -= off - key.offset;
                                }

                                if (key.offset + datal > off + len)
                                        datal = off + len - key.offset;

                                ret = btrfs_drop_extents(trans, inode,
                                                         new_key.offset,
                                                         new_key.offset + datal,
                                                         &hint_byte, 1);
                                BUG_ON(ret);

                                ret = btrfs_insert_empty_item(trans, root, path,
                                                              &new_key, size);
                                BUG_ON(ret);

                                leaf = path->nodes[0];
                                slot = path->slots[0];
                                write_extent_buffer(leaf, buf,
                                            btrfs_item_ptr_offset(leaf, slot),
                                            size);

                                extent = btrfs_item_ptr(leaf, slot,
                                                struct btrfs_file_extent_item);

                                /* disko == 0 means it's a hole */
                                if (!disko)
                                        datao = 0;

                                btrfs_set_file_extent_offset(leaf, extent,
                                                             datao);
                                btrfs_set_file_extent_num_bytes(leaf, extent,
                                                                datal);
                                if (disko) {
                                        inode_add_bytes(inode, datal);
                                        ret = btrfs_inc_extent_ref(trans, root,
                                                        disko, diskl, 0,
                                                        root->root_key.objectid,
                                                        inode->i_ino,
                                                        new_key.offset - datao);
                                        BUG_ON(ret);
                                }
                        } else if (type == BTRFS_FILE_EXTENT_INLINE) {
                                u64 skip = 0;
                                u64 trim = 0;
                                if (off > key.offset) {
                                        skip = off - key.offset;
                                        new_key.offset += skip;
                                }

                                if (key.offset + datal > off+len)
                                        trim = key.offset + datal - (off+len);

                                if (comp && (skip || trim)) {
                                        ret = -EINVAL;
                                        btrfs_end_transaction(trans, root);
                                        goto out;
                                }
                                size -= skip + trim;
                                datal -= skip + trim;

                                ret = btrfs_drop_extents(trans, inode,
                                                         new_key.offset,
                                                         new_key.offset + datal,
                                                         &hint_byte, 1);
                                BUG_ON(ret);

                                ret = btrfs_insert_empty_item(trans, root, path,
                                                              &new_key, size);
                                BUG_ON(ret);

                                if (skip) {
                                        u32 start =
                                          btrfs_file_extent_calc_inline_size(0);
                                        memmove(buf+start, buf+start+skip,
                                                datal);
                                }

                                leaf = path->nodes[0];
                                slot = path->slots[0];
                                write_extent_buffer(leaf, buf,
                                            btrfs_item_ptr_offset(leaf, slot),
                                            size);
                                inode_add_bytes(inode, datal);
                        }

                        btrfs_mark_buffer_dirty(leaf);
                        btrfs_release_path(root, path);

                        inode->i_mtime = inode->i_ctime = CURRENT_TIME;

                        /*
                         * we round up to the block size at eof when
                         * determining which extents to clone above,
                         * but shouldn't round up the file size
                         */
                        endoff = new_key.offset + datal;
                        if (endoff > destoff+olen)
                                endoff = destoff+olen;
                        if (endoff > inode->i_size)
                                btrfs_i_size_write(inode, endoff);

                        BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
                        ret = btrfs_update_inode(trans, root, inode);
                        BUG_ON(ret);
                        btrfs_end_transaction(trans, root);
                }
next:
                btrfs_release_path(root, path);
                key.offset++;
        }
        ret = 0;
out:
        btrfs_release_path(root, path);
        unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
out_unlock:
        mutex_unlock(&src->i_mutex);
        mutex_unlock(&inode->i_mutex);
        vfree(buf);
        btrfs_free_path(path);
out_fput:
        fput(src_file);
out_drop_write:
        mnt_drop_write(file->f_path.mnt);
        return ret;
}

static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
{
        struct btrfs_ioctl_clone_range_args args;

        if (copy_from_user(&args, argp, sizeof(args)))
                return -EFAULT;
        return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
                                 args.src_length, args.dest_offset);
}

/*
 * there are many ways the trans_start and trans_end ioctls can lead
 * to deadlocks.  They should only be used by applications that
 * basically own the machine, and have a very in depth understanding
 * of all the possible deadlocks and enospc problems.
 */
static long btrfs_ioctl_trans_start(struct file *file)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct btrfs_trans_handle *trans;
        int ret;

        ret = -EPERM;
        if (!capable(CAP_SYS_ADMIN))
                goto out;

        ret = -EINPROGRESS;
        if (file->private_data)
                goto out;

        ret = -EROFS;
        if (btrfs_root_readonly(root))
                goto out;

        ret = mnt_want_write(file->f_path.mnt);
        if (ret)
                goto out;

        mutex_lock(&root->fs_info->trans_mutex);
        root->fs_info->open_ioctl_trans++;
        mutex_unlock(&root->fs_info->trans_mutex);

        ret = -ENOMEM;
        trans = btrfs_start_ioctl_transaction(root, 0);
        if (IS_ERR(trans))
                goto out_drop;

        file->private_data = trans;
        return 0;

out_drop:
        mutex_lock(&root->fs_info->trans_mutex);
        root->fs_info->open_ioctl_trans--;
        mutex_unlock(&root->fs_info->trans_mutex);
        mnt_drop_write(file->f_path.mnt);
out:
        return ret;
}

static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct btrfs_root *new_root;
        struct btrfs_dir_item *di;
        struct btrfs_trans_handle *trans;
        struct btrfs_path *path;
        struct btrfs_key location;
        struct btrfs_disk_key disk_key;
        struct btrfs_super_block *disk_super;
        u64 features;
        u64 objectid = 0;
        u64 dir_id;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (copy_from_user(&objectid, argp, sizeof(objectid)))
                return -EFAULT;

        if (!objectid)
                objectid = root->root_key.objectid;

        location.objectid = objectid;
        location.type = BTRFS_ROOT_ITEM_KEY;
        location.offset = (u64)-1;

        new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
        if (IS_ERR(new_root))
                return PTR_ERR(new_root);

        if (btrfs_root_refs(&new_root->root_item) == 0)
                return -ENOENT;

        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
        path->leave_spinning = 1;

        trans = btrfs_start_transaction(root, 1);
        if (IS_ERR(trans)) {
                btrfs_free_path(path);
                return PTR_ERR(trans);
        }

        dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
        di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
                                   dir_id, "default", 7, 1);
        if (IS_ERR_OR_NULL(di)) {
                btrfs_free_path(path);
                btrfs_end_transaction(trans, root);
                printk(KERN_ERR "Umm, you don't have the default dir item, "
                       "this isn't going to work\n");
                return -ENOENT;
        }

        btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
        btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
        btrfs_mark_buffer_dirty(path->nodes[0]);
        btrfs_free_path(path);

        disk_super = &root->fs_info->super_copy;
        features = btrfs_super_incompat_flags(disk_super);
        if (!(features & BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)) {
                features |= BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL;
                btrfs_set_super_incompat_flags(disk_super, features);
        }
        btrfs_end_transaction(trans, root);

        return 0;
}

static void get_block_group_info(struct list_head *groups_list,
                                 struct btrfs_ioctl_space_info *space)
{
        struct btrfs_block_group_cache *block_group;

        space->total_bytes = 0;
        space->used_bytes = 0;
        space->flags = 0;
        list_for_each_entry(block_group, groups_list, list) {
                space->flags = block_group->flags;
                space->total_bytes += block_group->key.offset;
                space->used_bytes +=
                        btrfs_block_group_used(&block_group->item);
        }
}

long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
{
        struct btrfs_ioctl_space_args space_args;
        struct btrfs_ioctl_space_info space;
        struct btrfs_ioctl_space_info *dest;
        struct btrfs_ioctl_space_info *dest_orig;
        struct btrfs_ioctl_space_info *user_dest;
        struct btrfs_space_info *info;
        u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
                       BTRFS_BLOCK_GROUP_SYSTEM,
                       BTRFS_BLOCK_GROUP_METADATA,
                       BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
        int num_types = 4;
        int alloc_size;
        int ret = 0;
        u64 slot_count = 0;
        int i, c;

        if (copy_from_user(&space_args,
                           (struct btrfs_ioctl_space_args __user *)arg,
                           sizeof(space_args)))
                return -EFAULT;

        for (i = 0; i < num_types; i++) {
                struct btrfs_space_info *tmp;

                info = NULL;
                rcu_read_lock();
                list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
                                        list) {
                        if (tmp->flags == types[i]) {
                                info = tmp;
                                break;
                        }
                }
                rcu_read_unlock();

                if (!info)
                        continue;

                down_read(&info->groups_sem);
                for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
                        if (!list_empty(&info->block_groups[c]))
                                slot_count++;
                }
                up_read(&info->groups_sem);
        }

        /* space_slots == 0 means they are asking for a count */
        if (space_args.space_slots == 0) {
                space_args.total_spaces = slot_count;
                goto out;
        }

        slot_count = min_t(u64, space_args.space_slots, slot_count);

        alloc_size = sizeof(*dest) * slot_count;

        /* we generally have at most 6 or so space infos, one for each raid
         * level.  So, a whole page should be more than enough for everyone
         */
        if (alloc_size > PAGE_CACHE_SIZE)
                return -ENOMEM;

        space_args.total_spaces = 0;
        dest = kmalloc(alloc_size, GFP_NOFS);
        if (!dest)
                return -ENOMEM;
        dest_orig = dest;

        /* now we have a buffer to copy into */
        for (i = 0; i < num_types; i++) {
                struct btrfs_space_info *tmp;

                if (!slot_count)
                        break;

                info = NULL;
                rcu_read_lock();
                list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
                                        list) {
                        if (tmp->flags == types[i]) {
                                info = tmp;
                                break;
                        }
                }
                rcu_read_unlock();

                if (!info)
                        continue;
                down_read(&info->groups_sem);
                for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
                        if (!list_empty(&info->block_groups[c])) {
                                get_block_group_info(&info->block_groups[c],
                                                     &space);
                                memcpy(dest, &space, sizeof(space));
                                dest++;
                                space_args.total_spaces++;
                                slot_count--;
                        }
                        if (!slot_count)
                                break;
                }
                up_read(&info->groups_sem);
        }

        user_dest = (struct btrfs_ioctl_space_info *)
                (arg + sizeof(struct btrfs_ioctl_space_args));

        if (copy_to_user(user_dest, dest_orig, alloc_size))
                ret = -EFAULT;

        kfree(dest_orig);
out:
        if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
                ret = -EFAULT;

        return ret;
}

/*
 * there are many ways the trans_start and trans_end ioctls can lead
 * to deadlocks.  They should only be used by applications that
 * basically own the machine, and have a very in depth understanding
 * of all the possible deadlocks and enospc problems.
 */
long btrfs_ioctl_trans_end(struct file *file)
{
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct btrfs_trans_handle *trans;

        trans = file->private_data;
        if (!trans)
                return -EINVAL;
        file->private_data = NULL;

        btrfs_end_transaction(trans, root);

        mutex_lock(&root->fs_info->trans_mutex);
        root->fs_info->open_ioctl_trans--;
        mutex_unlock(&root->fs_info->trans_mutex);

        mnt_drop_write(file->f_path.mnt);
        return 0;
}

static noinline long btrfs_ioctl_start_sync(struct file *file, void __user *argp)
{
        struct btrfs_root *root = BTRFS_I(file->f_dentry->d_inode)->root;
        struct btrfs_trans_handle *trans;
        u64 transid;

        trans = btrfs_start_transaction(root, 0);
        if (IS_ERR(trans))
                return PTR_ERR(trans);
        transid = trans->transid;
        btrfs_commit_transaction_async(trans, root, 0);

        if (argp)
                if (copy_to_user(argp, &transid, sizeof(transid)))
                        return -EFAULT;
        return 0;
}

static noinline long btrfs_ioctl_wait_sync(struct file *file, void __user *argp)
{
        struct btrfs_root *root = BTRFS_I(file->f_dentry->d_inode)->root;
        u64 transid;

        if (argp) {
                if (copy_from_user(&transid, argp, sizeof(transid)))
                        return -EFAULT;
        } else {
                transid = 0;  /* current trans */
        }
        return btrfs_wait_for_commit(root, transid);
}

long btrfs_ioctl(struct file *file, unsigned int
                cmd, unsigned long arg)
{
        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
        void __user *argp = (void __user *)arg;

        switch (cmd) {
        case FS_IOC_GETFLAGS:
                return btrfs_ioctl_getflags(file, argp);
        case FS_IOC_SETFLAGS:
                return btrfs_ioctl_setflags(file, argp);
        case FS_IOC_GETVERSION:
                return btrfs_ioctl_getversion(file, argp);
        case BTRFS_IOC_SNAP_CREATE:
                return btrfs_ioctl_snap_create(file, argp, 0);
        case BTRFS_IOC_SNAP_CREATE_V2:
                return btrfs_ioctl_snap_create_v2(file, argp, 0);
        case BTRFS_IOC_SUBVOL_CREATE:
                return btrfs_ioctl_snap_create(file, argp, 1);
        case BTRFS_IOC_SNAP_DESTROY:
                return btrfs_ioctl_snap_destroy(file, argp);
        case BTRFS_IOC_SUBVOL_GETFLAGS:
                return btrfs_ioctl_subvol_getflags(file, argp);
        case BTRFS_IOC_SUBVOL_SETFLAGS:
                return btrfs_ioctl_subvol_setflags(file, argp);
        case BTRFS_IOC_DEFAULT_SUBVOL:
                return btrfs_ioctl_default_subvol(file, argp);
        case BTRFS_IOC_DEFRAG:
                return btrfs_ioctl_defrag(file, NULL);
        case BTRFS_IOC_DEFRAG_RANGE:
                return btrfs_ioctl_defrag(file, argp);
        case BTRFS_IOC_RESIZE:
                return btrfs_ioctl_resize(root, argp);
        case BTRFS_IOC_ADD_DEV:
                return btrfs_ioctl_add_dev(root, argp);
        case BTRFS_IOC_RM_DEV:
                return btrfs_ioctl_rm_dev(root, argp);
        case BTRFS_IOC_BALANCE:
                return btrfs_balance(root->fs_info->dev_root);
        case BTRFS_IOC_CLONE:
                return btrfs_ioctl_clone(file, arg, 0, 0, 0);
        case BTRFS_IOC_CLONE_RANGE:
                return btrfs_ioctl_clone_range(file, argp);
        case BTRFS_IOC_TRANS_START:
                return btrfs_ioctl_trans_start(file);
        case BTRFS_IOC_TRANS_END:
                return btrfs_ioctl_trans_end(file);
        case BTRFS_IOC_TREE_SEARCH:
                return btrfs_ioctl_tree_search(file, argp);
        case BTRFS_IOC_INO_LOOKUP:
                return btrfs_ioctl_ino_lookup(file, argp);
        case BTRFS_IOC_SPACE_INFO:
                return btrfs_ioctl_space_info(root, argp);
        case BTRFS_IOC_SYNC:
                btrfs_sync_fs(file->f_dentry->d_sb, 1);
                return 0;
        case BTRFS_IOC_START_SYNC:
                return btrfs_ioctl_start_sync(file, argp);
        case BTRFS_IOC_WAIT_SYNC:
                return btrfs_ioctl_wait_sync(file, argp);
        }

        return -ENOTTY;
}