[deliverable/linux.git] / fs / btrfs / ioctl.c

/*
 * 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/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/bit_spinlock.h>
#include <linux/version.h>
#include <linux/xattr.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"


static noinline int create_subvol(struct btrfs_root *root, char *name,
				  int namelen)
{
	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 = root;
	struct inode *dir;
	int ret;
	int err;
	u64 objectid;
	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
	unsigned long nr = 1;

	mutex_lock(&root->fs_info->fs_mutex);
	ret = btrfs_check_free_space(root, 1, 0);
	if (ret)
		goto fail_commit;

	trans = btrfs_start_transaction(root, 1);
	BUG_ON(!trans);

	ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
				       0, &objectid);
	if (ret)
		goto fail;

	leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
				      objectid, trans->transid, 0, 0,
				      0, 0);
	if (IS_ERR(leaf))
		return PTR_ERR(leaf);

	btrfs_set_header_nritems(leaf, 0);
	btrfs_set_header_level(leaf, 0);
	btrfs_set_header_bytenr(leaf, leaf->start);
	btrfs_set_header_generation(leaf, trans->transid);
	btrfs_set_header_owner(leaf, objectid);

	write_extent_buffer(leaf, root->fs_info->fsid,
			    (unsigned long)btrfs_header_fsid(leaf),
			    BTRFS_FSID_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->nblocks = cpu_to_le64(1);
	inode_item->mode = cpu_to_le32(S_IFDIR | 0755);

	btrfs_set_root_bytenr(&root_item, leaf->start);
	btrfs_set_root_level(&root_item, 0);
	btrfs_set_root_refs(&root_item, 1);
	btrfs_set_root_used(&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 = 1;
	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;

	/*
	 * insert the directory item
	 */
	key.offset = (u64)-1;
	dir = root->fs_info->sb->s_root->d_inode;
	ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
				    name, namelen, dir->i_ino, &key,
				    BTRFS_FT_DIR);
	if (ret)
		goto fail;

	ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
			     name, namelen, objectid,
			     root->fs_info->sb->s_root->d_inode->i_ino);
	if (ret)
		goto fail;

	ret = btrfs_commit_transaction(trans, root);
	if (ret)
		goto fail_commit;

	new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
	BUG_ON(!new_root);

	trans = btrfs_start_transaction(new_root, 1);
	BUG_ON(!trans);

	ret = btrfs_create_subvol_root(new_root, trans, new_dirid,
				       BTRFS_I(dir)->block_group);
	if (ret)
		goto fail;

	/* Invalidate existing dcache entry for new subvolume. */
	btrfs_invalidate_dcache_root(root, name, namelen);

fail:
	nr = trans->blocks_used;
	err = btrfs_commit_transaction(trans, new_root);
	if (err && !ret)
		ret = err;
fail_commit:
	mutex_unlock(&root->fs_info->fs_mutex);
	btrfs_btree_balance_dirty(root, nr);
	btrfs_throttle(root);
	return ret;
}

static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
{
	struct btrfs_pending_snapshot *pending_snapshot;
	struct btrfs_trans_handle *trans;
	int ret;
	int err;
	unsigned long nr = 0;

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

	mutex_lock(&root->fs_info->fs_mutex);
	ret = btrfs_check_free_space(root, 1, 0);
	if (ret)
		goto fail_unlock;

	pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
	if (!pending_snapshot) {
		ret = -ENOMEM;
		goto fail_unlock;
	}
	pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
	if (!pending_snapshot->name) {
		ret = -ENOMEM;
		kfree(pending_snapshot);
		goto fail_unlock;
	}
	memcpy(pending_snapshot->name, name, namelen);
	pending_snapshot->name[namelen] = '\0';
	trans = btrfs_start_transaction(root, 1);
	BUG_ON(!trans);
	pending_snapshot->root = root;
	list_add(&pending_snapshot->list,
		 &trans->transaction->pending_snapshots);
	ret = btrfs_update_inode(trans, root, root->inode);
	err = btrfs_commit_transaction(trans, root);

fail_unlock:
	mutex_unlock(&root->fs_info->fs_mutex);
	btrfs_btree_balance_dirty(root, nr);
	btrfs_throttle(root);
	return ret;
}

int btrfs_defrag_file(struct file *file)
{
	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 page *page;
	unsigned long last_index;
	unsigned long ra_pages = root->fs_info->bdi.ra_pages;
	unsigned long total_read = 0;
	u64 page_start;
	u64 page_end;
	unsigned long i;
	int ret;

	mutex_lock(&root->fs_info->fs_mutex);
	ret = btrfs_check_free_space(root, inode->i_size, 0);
	mutex_unlock(&root->fs_info->fs_mutex);
	if (ret)
		return -ENOSPC;

	mutex_lock(&inode->i_mutex);
	last_index = inode->i_size >> PAGE_CACHE_SHIFT;
	for (i = 0; i <= last_index; i++) {
		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++;
		page = grab_cache_page(inode->i_mapping, i);
		if (!page)
			goto out_unlock;
		if (!PageUptodate(page)) {
			btrfs_readpage(NULL, page);
			lock_page(page);
			if (!PageUptodate(page)) {
				unlock_page(page);
				page_cache_release(page);
				goto out_unlock;
			}
		}

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
		ClearPageDirty(page);
#else
		cancel_dirty_page(page, PAGE_CACHE_SIZE);
#endif
		wait_on_page_writeback(page);
		set_page_extent_mapped(page);

		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);
		set_extent_delalloc(io_tree, page_start,
				    page_end, GFP_NOFS);

		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
		set_page_dirty(page);
		unlock_page(page);
		page_cache_release(page);
		balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
	}

out_unlock:
	mutex_unlock(&inode->i_mutex);
	return 0;
}

/*
 * Called inside transaction, so use GFP_NOFS
 */

static 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 namelen;
	int mod = 0;

	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);

	if (!vol_args)
		return -ENOMEM;

	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
		ret = -EFAULT;
		goto out;
	}
	namelen = strlen(vol_args->name);
	if (namelen > BTRFS_VOL_NAME_MAX) {
		ret = -EINVAL;
		goto out;
	}

	mutex_lock(&root->fs_info->fs_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", devid);
	}
	device = btrfs_find_device(root, devid, NULL);
	if (!device) {
		printk(KERN_INFO "resizer unable to find device %llu\n", 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 = btrfs_parse_size(sizestr);
		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, 1);
		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->fs_mutex);
out:
	kfree(vol_args);
	return ret;
}

static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
					    void __user *arg)
{
	struct btrfs_ioctl_vol_args *vol_args;
	struct btrfs_dir_item *di;
	struct btrfs_path *path;
	u64 root_dirid;
	int namelen;
	int ret;

	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);

	if (!vol_args)
		return -ENOMEM;

	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
		ret = -EFAULT;
		goto out;
	}

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

	path = btrfs_alloc_path();
	if (!path) {
		ret = -ENOMEM;
		goto out;
	}

	root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
	mutex_lock(&root->fs_info->fs_mutex);
	di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
			    path, root_dirid,
			    vol_args->name, namelen, 0);
	mutex_unlock(&root->fs_info->fs_mutex);
	btrfs_free_path(path);

	if (di && !IS_ERR(di)) {
		ret = -EEXIST;
		goto out;
	}

	if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}

	if (root == root->fs_info->tree_root)
		ret = create_subvol(root, vol_args->name, namelen);
	else
		ret = create_snapshot(root, vol_args->name, namelen);
out:
	kfree(vol_args);
	return ret;
}

static int btrfs_ioctl_defrag(struct file *file)
{
	struct inode *inode = fdentry(file)->d_inode;
	struct btrfs_root *root = BTRFS_I(inode)->root;

	switch (inode->i_mode & S_IFMT) {
	case S_IFDIR:
		mutex_lock(&root->fs_info->fs_mutex);
		btrfs_defrag_root(root, 0);
		btrfs_defrag_root(root->fs_info->extent_root, 0);
		mutex_unlock(&root->fs_info->fs_mutex);
		break;
	case S_IFREG:
		btrfs_defrag_file(file);
		break;
	}

	return 0;
}

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

	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);

	if (!vol_args)
		return -ENOMEM;

	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
		ret = -EFAULT;
		goto out;
	}
	ret = btrfs_init_new_device(root, vol_args->name);

out:
	kfree(vol_args);
	return ret;
}

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

	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);

	if (!vol_args)
		return -ENOMEM;

	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
		ret = -EFAULT;
		goto out;
	}
	ret = btrfs_rm_device(root, vol_args->name);

out:
	kfree(vol_args);
	return ret;
}

int dup_item_to_inode(struct btrfs_trans_handle *trans,
		       struct btrfs_root *root,
		       struct btrfs_path *path,
		       struct extent_buffer *leaf,
		       int slot,
		       struct btrfs_key *key,
		       u64 destino)
{
	char *dup;
	int len = btrfs_item_size_nr(leaf, slot);
	struct btrfs_key ckey = *key;
	int ret = 0;

	dup = kmalloc(len, GFP_NOFS);
	if (!dup)
		return -ENOMEM;

	read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
	btrfs_release_path(root, path);

	ckey.objectid = destino;
	ret = btrfs_insert_item(trans, root, &ckey, dup, len);
	kfree(dup);
	return ret;
}

long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
{
	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;
	int ret;
	u64 pos;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct extent_buffer *leaf;
	u32 nritems;
	int slot;

	src_file = fget(src_fd);
	if (!src_file)
		return -EBADF;
	src = src_file->f_dentry->d_inode;

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

	if (inode < src) {
		mutex_lock(&inode->i_mutex);
		mutex_lock(&src->i_mutex);
	} else {
		mutex_lock(&src->i_mutex);
		mutex_lock(&inode->i_mutex);
	}

	ret = -ENOTEMPTY;
	if (inode->i_size)
		goto out_unlock;

	/* do any pending delalloc/csum calc on src, one way or
	   another, and lock file content */
	while (1) {
		filemap_write_and_wait(src->i_mapping);
		lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
		if (BTRFS_I(src)->delalloc_bytes == 0)
			break;
		unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
	}

	mutex_lock(&root->fs_info->fs_mutex);
	trans = btrfs_start_transaction(root, 0);
	path = btrfs_alloc_path();
	if (!path) {
		ret = -ENOMEM;
		goto out;
	}
	key.offset = 0;
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.objectid = src->i_ino;
	pos = 0;
	path->reada = 2;

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

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

		if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
		    key.objectid != src->i_ino)
			break;

		if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
			struct btrfs_file_extent_item *extent;
			int found_type;
			pos = key.offset;
			extent = btrfs_item_ptr(leaf, slot,
						struct btrfs_file_extent_item);
			found_type = btrfs_file_extent_type(leaf, extent);
			if (found_type == BTRFS_FILE_EXTENT_REG) {
				u64 len = btrfs_file_extent_num_bytes(leaf,
								      extent);
				u64 ds = btrfs_file_extent_disk_bytenr(leaf,
								       extent);
				u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
								 extent);
				u64 off = btrfs_file_extent_offset(leaf,
								   extent);
				btrfs_insert_file_extent(trans, root,
							 inode->i_ino, pos,
							 ds, dl, len, off);
				/* ds == 0 means there's a hole */
				if (ds != 0) {
					btrfs_inc_extent_ref(trans, root,
						     ds, dl,
						     root->root_key.objectid,
						     trans->transid,
						     inode->i_ino, pos);
				}
				pos = key.offset + len;
			} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
				ret = dup_item_to_inode(trans, root, path,
							leaf, slot, &key,
							inode->i_ino);
				if (ret)
					goto out;
				pos = key.offset + btrfs_item_size_nr(leaf,
								      slot);
			}
		} else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
			ret = dup_item_to_inode(trans, root, path, leaf,
						slot, &key, inode->i_ino);

			if (ret)
				goto out;
		}
		key.offset++;
		btrfs_release_path(root, path);
	}

	ret = 0;
out:
	btrfs_free_path(path);

	inode->i_blocks = src->i_blocks;
	i_size_write(inode, src->i_size);
	btrfs_update_inode(trans, root, inode);

	unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);

	btrfs_end_transaction(trans, root);
	mutex_unlock(&root->fs_info->fs_mutex);

out_unlock:
	mutex_unlock(&src->i_mutex);
	mutex_unlock(&inode->i_mutex);
out_fput:
	fput(src_file);
	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_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 = 0;

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

	mutex_lock(&root->fs_info->fs_mutex);
	if (file->private_data) {
		ret = -EINPROGRESS;
		goto out;
	}
	trans = btrfs_start_transaction(root, 0);
	if (trans)
		file->private_data = trans;
	else
		ret = -ENOMEM;
	/*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
out:
	mutex_unlock(&root->fs_info->fs_mutex);
	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;
	int ret = 0;

	mutex_lock(&root->fs_info->fs_mutex);
	trans = file->private_data;
	if (!trans) {
		ret = -EINVAL;
		goto out;
	}
	btrfs_end_transaction(trans, root);
	file->private_data = 0;
out:
	mutex_unlock(&root->fs_info->fs_mutex);
	return ret;
}

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

	switch (cmd) {
	case BTRFS_IOC_SNAP_CREATE:
		return btrfs_ioctl_snap_create(root, (void __user *)arg);
	case BTRFS_IOC_DEFRAG:
		return btrfs_ioctl_defrag(file);
	case BTRFS_IOC_RESIZE:
		return btrfs_ioctl_resize(root, (void __user *)arg);
	case BTRFS_IOC_ADD_DEV:
		return btrfs_ioctl_add_dev(root, (void __user *)arg);
	case BTRFS_IOC_RM_DEV:
		return btrfs_ioctl_rm_dev(root, (void __user *)arg);
	case BTRFS_IOC_BALANCE:
		return btrfs_balance(root->fs_info->dev_root);
	case BTRFS_IOC_CLONE:
		return btrfs_ioctl_clone(file, arg);
	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_SYNC:
		btrfs_sync_fs(file->f_dentry->d_sb, 1);
		return 0;
	}

	return -ENOTTY;
}
Commit	Line	Data
f46b5a66 CH	1	/*
	2	* Copyright (C) 2007 Oracle. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
	19	#include <linux/kernel.h>
	20	#include <linux/bio.h>
	21	#include <linux/buffer_head.h>
	22	#include <linux/file.h>
	23	#include <linux/fs.h>
	24	#include <linux/pagemap.h>
	25	#include <linux/highmem.h>
	26	#include <linux/time.h>
	27	#include <linux/init.h>
	28	#include <linux/string.h>
	29	#include <linux/smp_lock.h>
	30	#include <linux/backing-dev.h>
	31	#include <linux/mpage.h>
	32	#include <linux/swap.h>
	33	#include <linux/writeback.h>
	34	#include <linux/statfs.h>
	35	#include <linux/compat.h>
	36	#include <linux/bit_spinlock.h>
	37	#include <linux/version.h>
	38	#include <linux/xattr.h>
	39	#include "ctree.h"
	40	#include "disk-io.h"
	41	#include "transaction.h"
	42	#include "btrfs_inode.h"
	43	#include "ioctl.h"
	44	#include "print-tree.h"
	45	#include "volumes.h"
925baedd	46	#include "locking.h"
f46b5a66 CH	47
	48
	49
	50	static noinline int create_subvol(struct btrfs_root root, char name,
	51	int namelen)
	52	{
	53	struct btrfs_trans_handle *trans;
	54	struct btrfs_key key;
	55	struct btrfs_root_item root_item;
	56	struct btrfs_inode_item *inode_item;
	57	struct extent_buffer *leaf;
	58	struct btrfs_root *new_root = root;
	59	struct inode *dir;
	60	int ret;
	61	int err;
	62	u64 objectid;
	63	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
	64	unsigned long nr = 1;
	65
	66	mutex_lock(&root->fs_info->fs_mutex);
	67	ret = btrfs_check_free_space(root, 1, 0);
	68	if (ret)
	69	goto fail_commit;
	70
	71	trans = btrfs_start_transaction(root, 1);
	72	BUG_ON(!trans);
	73
	74	ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
	75	0, &objectid);
	76	if (ret)
	77	goto fail;
	78
925baedd CM	79	leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
	80	objectid, trans->transid, 0, 0,
	81	0, 0);
f46b5a66 CH	82	if (IS_ERR(leaf))
	83	return PTR_ERR(leaf);
	84
	85	btrfs_set_header_nritems(leaf, 0);
	86	btrfs_set_header_level(leaf, 0);
	87	btrfs_set_header_bytenr(leaf, leaf->start);
	88	btrfs_set_header_generation(leaf, trans->transid);
	89	btrfs_set_header_owner(leaf, objectid);
	90
	91	write_extent_buffer(leaf, root->fs_info->fsid,
	92	(unsigned long)btrfs_header_fsid(leaf),
	93	BTRFS_FSID_SIZE);
	94	btrfs_mark_buffer_dirty(leaf);
	95
	96	inode_item = &root_item.inode;
	97	memset(inode_item, 0, sizeof(*inode_item));
	98	inode_item->generation = cpu_to_le64(1);
	99	inode_item->size = cpu_to_le64(3);
	100	inode_item->nlink = cpu_to_le32(1);
	101	inode_item->nblocks = cpu_to_le64(1);
	102	inode_item->mode = cpu_to_le32(S_IFDIR \| 0755);
	103
	104	btrfs_set_root_bytenr(&root_item, leaf->start);
	105	btrfs_set_root_level(&root_item, 0);
	106	btrfs_set_root_refs(&root_item, 1);
	107	btrfs_set_root_used(&root_item, 0);
	108
	109	memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
	110	root_item.drop_level = 0;
	111
925baedd	112	btrfs_tree_unlock(leaf);
f46b5a66 CH	113	free_extent_buffer(leaf);
	114	leaf = NULL;
	115
	116	btrfs_set_root_dirid(&root_item, new_dirid);
	117
	118	key.objectid = objectid;
	119	key.offset = 1;
	120	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	121	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
	122	&root_item);
	123	if (ret)
	124	goto fail;
	125
	126	/*
	127	* insert the directory item
	128	*/
	129	key.offset = (u64)-1;
	130	dir = root->fs_info->sb->s_root->d_inode;
	131	ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
	132	name, namelen, dir->i_ino, &key,
	133	BTRFS_FT_DIR);
	134	if (ret)
	135	goto fail;
	136
	137	ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
	138	name, namelen, objectid,
	139	root->fs_info->sb->s_root->d_inode->i_ino);
	140	if (ret)
	141	goto fail;
	142
	143	ret = btrfs_commit_transaction(trans, root);
	144	if (ret)
	145	goto fail_commit;
	146
	147	new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
	148	BUG_ON(!new_root);
	149
	150	trans = btrfs_start_transaction(new_root, 1);
	151	BUG_ON(!trans);
	152
	153	ret = btrfs_create_subvol_root(new_root, trans, new_dirid,
	154	BTRFS_I(dir)->block_group);
	155	if (ret)
	156	goto fail;
	157
	158	/* Invalidate existing dcache entry for new subvolume. */
	159	btrfs_invalidate_dcache_root(root, name, namelen);
	160
	161	fail:
	162	nr = trans->blocks_used;
	163	err = btrfs_commit_transaction(trans, new_root);
	164	if (err && !ret)
	165	ret = err;
	166	fail_commit:
	167	mutex_unlock(&root->fs_info->fs_mutex);
	168	btrfs_btree_balance_dirty(root, nr);
	169	btrfs_throttle(root);
	170	return ret;
	171	}
	172
	173	static int create_snapshot(struct btrfs_root root, char name, int namelen)
	174	{
	175	struct btrfs_pending_snapshot *pending_snapshot;
	176	struct btrfs_trans_handle *trans;
177	int ret;
178	int err;
179	unsigned long nr = 0;
180
181	if (!root->ref_cows)
182	return -EINVAL;
183
184	mutex_lock(&root->fs_info->fs_mutex);
185	ret = btrfs_check_free_space(root, 1, 0);
186	if (ret)
187	goto fail_unlock;
188
189	pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
190	if (!pending_snapshot) {
191	ret = -ENOMEM;
192	goto fail_unlock;
193	}
194	pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
195	if (!pending_snapshot->name) {
196	ret = -ENOMEM;
197	kfree(pending_snapshot);
198	goto fail_unlock;
199	}
200	memcpy(pending_snapshot->name, name, namelen);
201	pending_snapshot->name[namelen] = '\0';
202	trans = btrfs_start_transaction(root, 1);
203	BUG_ON(!trans);
204	pending_snapshot->root = root;
205	list_add(&pending_snapshot->list,
206	&trans->transaction->pending_snapshots);
207	ret = btrfs_update_inode(trans, root, root->inode);
208	err = btrfs_commit_transaction(trans, root);
209
210	fail_unlock:
211	mutex_unlock(&root->fs_info->fs_mutex);
212	btrfs_btree_balance_dirty(root, nr);
213	btrfs_throttle(root);
214	return ret;
215	}
216
217	int btrfs_defrag_file(struct file *file)
218	{
219	struct inode *inode = fdentry(file)->d_inode;
220	struct btrfs_root *root = BTRFS_I(inode)->root;
221	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
222	struct page *page;
223	unsigned long last_index;
224	unsigned long ra_pages = root->fs_info->bdi.ra_pages;
225	unsigned long total_read = 0;
226	u64 page_start;
227	u64 page_end;
228	unsigned long i;
229	int ret;
230
231	mutex_lock(&root->fs_info->fs_mutex);
232	ret = btrfs_check_free_space(root, inode->i_size, 0);
233	mutex_unlock(&root->fs_info->fs_mutex);
234	if (ret)
235	return -ENOSPC;
236
237	mutex_lock(&inode->i_mutex);
238	last_index = inode->i_size >> PAGE_CACHE_SHIFT;
239	for (i = 0; i <= last_index; i++) {
240	if (total_read % ra_pages == 0) {
241	btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
242	min(last_index, i + ra_pages - 1));
243	}
244	total_read++;
245	page = grab_cache_page(inode->i_mapping, i);
246	if (!page)
247	goto out_unlock;
248	if (!PageUptodate(page)) {
249	btrfs_readpage(NULL, page);
250	lock_page(page);
251	if (!PageUptodate(page)) {
252	unlock_page(page);
253	page_cache_release(page);
254	goto out_unlock;
255	}
256	}
257
258	#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
259	ClearPageDirty(page);
260	#else
261	cancel_dirty_page(page, PAGE_CACHE_SIZE);
262	#endif
263	wait_on_page_writeback(page);
264	set_page_extent_mapped(page);
265
266	page_start = (u64)page->index << PAGE_CACHE_SHIFT;
267	page_end = page_start + PAGE_CACHE_SIZE - 1;
268
269	lock_extent(io_tree, page_start, page_end, GFP_NOFS);
270	set_extent_delalloc(io_tree, page_start,
271	page_end, GFP_NOFS);
272
273	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
274	set_page_dirty(page);
275	unlock_page(page);
276	page_cache_release(page);
277	balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
278	}
279
280	out_unlock:
281	mutex_unlock(&inode->i_mutex);
282	return 0;
283	}
284
285	/*
286	* Called inside transaction, so use GFP_NOFS
287	*/
288
289	static int btrfs_ioctl_resize(struct btrfs_root root, void __user arg)
290	{
291	u64 new_size;
292	u64 old_size;
293	u64 devid = 1;
294	struct btrfs_ioctl_vol_args *vol_args;
295	struct btrfs_trans_handle *trans;
296	struct btrfs_device *device = NULL;
297	char *sizestr;
298	char *devstr = NULL;
299	int ret = 0;
300	int namelen;
301	int mod = 0;
302
303	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
304
305	if (!vol_args)
306	return -ENOMEM;
307
308	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
309	ret = -EFAULT;
310	goto out;
311	}
312	namelen = strlen(vol_args->name);
313	if (namelen > BTRFS_VOL_NAME_MAX) {
314	ret = -EINVAL;
315	goto out;
316	}
317
318	mutex_lock(&root->fs_info->fs_mutex);
319	sizestr = vol_args->name;
320	devstr = strchr(sizestr, ':');
321	if (devstr) {
322	char *end;
323	sizestr = devstr + 1;
324	*devstr = '\0';
325	devstr = vol_args->name;
326	devid = simple_strtoull(devstr, &end, 10);
327	printk(KERN_INFO "resizing devid %llu\n", devid);
328	}
329	device = btrfs_find_device(root, devid, NULL);
330	if (!device) {
331	printk(KERN_INFO "resizer unable to find device %llu\n", devid);
332	ret = -EINVAL;
333	goto out_unlock;
334	}
335	if (!strcmp(sizestr, "max"))
336	new_size = device->bdev->bd_inode->i_size;
337	else {
338	if (sizestr[0] == '-') {
339	mod = -1;
340	sizestr++;
341	} else if (sizestr[0] == '+') {
342	mod = 1;
343	sizestr++;
344	}
345	new_size = btrfs_parse_size(sizestr);
346	if (new_size == 0) {
347	ret = -EINVAL;
348	goto out_unlock;
349	}
350	}
351
352	old_size = device->total_bytes;
353
354	if (mod < 0) {
355	if (new_size > old_size) {
356	ret = -EINVAL;
357	goto out_unlock;
358	}
359	new_size = old_size - new_size;
360	} else if (mod > 0) {
361	new_size = old_size + new_size;
362	}
363
364	if (new_size < 256 * 1024 * 1024) {
365	ret = -EINVAL;
366	goto out_unlock;
367	}
368	if (new_size > device->bdev->bd_inode->i_size) {
369	ret = -EFBIG;
370	goto out_unlock;
371	}
372
373	do_div(new_size, root->sectorsize);
374	new_size *= root->sectorsize;
375
376	printk(KERN_INFO "new size for %s is %llu\n",
377	device->name, (unsigned long long)new_size);
378
379	if (new_size > old_size) {
380	trans = btrfs_start_transaction(root, 1);
381	ret = btrfs_grow_device(trans, device, new_size);
382	btrfs_commit_transaction(trans, root);
383	} else {
384	ret = btrfs_shrink_device(device, new_size);
385	}
386
387	out_unlock:
388	mutex_unlock(&root->fs_info->fs_mutex);
389	out:
390	kfree(vol_args);
391	return ret;
392	}
393
394	static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
395	void __user *arg)
396	{
397	struct btrfs_ioctl_vol_args *vol_args;
398	struct btrfs_dir_item *di;
399	struct btrfs_path *path;
400	u64 root_dirid;
401	int namelen;
402	int ret;
403
404	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
405
406	if (!vol_args)
407	return -ENOMEM;
408
409	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
410	ret = -EFAULT;
411	goto out;
412	}
413
414	namelen = strlen(vol_args->name);
415	if (namelen > BTRFS_VOL_NAME_MAX) {
416	ret = -EINVAL;
417	goto out;
418	}
419	if (strchr(vol_args->name, '/')) {
420	ret = -EINVAL;
421	goto out;
422	}
423
424	path = btrfs_alloc_path();
425	if (!path) {
426	ret = -ENOMEM;
427	goto out;
428	}
429
430	root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
431	mutex_lock(&root->fs_info->fs_mutex);
432	di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
433	path, root_dirid,
434	vol_args->name, namelen, 0);
435	mutex_unlock(&root->fs_info->fs_mutex);
436	btrfs_free_path(path);
437
438	if (di && !IS_ERR(di)) {
439	ret = -EEXIST;
440	goto out;
441	}
442
443	if (IS_ERR(di)) {
444	ret = PTR_ERR(di);
445	goto out;
446	}
447
448	if (root == root->fs_info->tree_root)
449	ret = create_subvol(root, vol_args->name, namelen);
450	else
451	ret = create_snapshot(root, vol_args->name, namelen);
452	out:
453	kfree(vol_args);
454	return ret;
455	}
456
457	static int btrfs_ioctl_defrag(struct file *file)
458	{
459	struct inode *inode = fdentry(file)->d_inode;
460	struct btrfs_root *root = BTRFS_I(inode)->root;
461
462	switch (inode->i_mode & S_IFMT) {
463	case S_IFDIR:
464	mutex_lock(&root->fs_info->fs_mutex);
465	btrfs_defrag_root(root, 0);
466	btrfs_defrag_root(root->fs_info->extent_root, 0);
467	mutex_unlock(&root->fs_info->fs_mutex);
468	break;
469	case S_IFREG:
470	btrfs_defrag_file(file);
471	break;
472	}
473
474	return 0;
475	}
476
477	long btrfs_ioctl_add_dev(struct btrfs_root root, void __user arg)
478	{
479	struct btrfs_ioctl_vol_args *vol_args;
480	int ret;
481
482	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
483
484	if (!vol_args)
485	return -ENOMEM;
486
487	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
488	ret = -EFAULT;
489	goto out;
490	}
491	ret = btrfs_init_new_device(root, vol_args->name);
492
493	out:
494	kfree(vol_args);
495	return ret;
496	}
497
498	long btrfs_ioctl_rm_dev(struct btrfs_root root, void __user arg)
499	{
500	struct btrfs_ioctl_vol_args *vol_args;
501	int ret;
502
503	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
504
505	if (!vol_args)
506	return -ENOMEM;
507
508	if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
509	ret = -EFAULT;
510	goto out;
511	}
512	ret = btrfs_rm_device(root, vol_args->name);
513
514	out:
515	kfree(vol_args);
516	return ret;
517	}
518
519	int dup_item_to_inode(struct btrfs_trans_handle *trans,
520	struct btrfs_root *root,
521	struct btrfs_path *path,
522	struct extent_buffer *leaf,
523	int slot,
524	struct btrfs_key *key,
525	u64 destino)
526	{
527	char *dup;
528	int len = btrfs_item_size_nr(leaf, slot);
529	struct btrfs_key ckey = *key;
530	int ret = 0;
531
532	dup = kmalloc(len, GFP_NOFS);
533	if (!dup)
534	return -ENOMEM;
535
536	read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
537	btrfs_release_path(root, path);
538
539	ckey.objectid = destino;
540	ret = btrfs_insert_item(trans, root, &ckey, dup, len);
541	kfree(dup);
542	return ret;
543	}
544
545	long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
546	{
547	struct inode *inode = fdentry(file)->d_inode;
548	struct btrfs_root *root = BTRFS_I(inode)->root;
549	struct file *src_file;
550	struct inode *src;
551	struct btrfs_trans_handle *trans;
552	int ret;
553	u64 pos;
554	struct btrfs_path *path;
555	struct btrfs_key key;
556	struct extent_buffer *leaf;
557	u32 nritems;
558	int slot;
559
560	src_file = fget(src_fd);
561	if (!src_file)
562	return -EBADF;
563	src = src_file->f_dentry->d_inode;
564
565	ret = -EXDEV;
566	if (src->i_sb != inode->i_sb)
567	goto out_fput;
568
569	if (inode < src) {
570	mutex_lock(&inode->i_mutex);
571	mutex_lock(&src->i_mutex);
572	} else {
573	mutex_lock(&src->i_mutex);
574	mutex_lock(&inode->i_mutex);
575	}
576
577	ret = -ENOTEMPTY;
578	if (inode->i_size)
579	goto out_unlock;
580
581	/* do any pending delalloc/csum calc on src, one way or
582	another, and lock file content */
583	while (1) {
584	filemap_write_and_wait(src->i_mapping);
585	lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
586	if (BTRFS_I(src)->delalloc_bytes == 0)
587	break;
588	unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
589	}
590
591	mutex_lock(&root->fs_info->fs_mutex);
592	trans = btrfs_start_transaction(root, 0);
593	path = btrfs_alloc_path();
594	if (!path) {
595	ret = -ENOMEM;
596	goto out;
597	}
598	key.offset = 0;
599	key.type = BTRFS_EXTENT_DATA_KEY;
600	key.objectid = src->i_ino;
601	pos = 0;
602	path->reada = 2;
603
604	while (1) {
605	/*
606	* note the key will change type as we walk through the
607	* tree.
608	*/
609	ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
610	if (ret < 0)
611	goto out;
612
613	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
614	ret = btrfs_next_leaf(root, path);
615	if (ret < 0)
616	goto out;
617	if (ret > 0)
618	break;
619	}
620	leaf = path->nodes[0];
621	slot = path->slots[0];
622	btrfs_item_key_to_cpu(leaf, &key, slot);
623	nritems = btrfs_header_nritems(leaf);
624
625	if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY \|\|
626	key.objectid != src->i_ino)
627	break;
628
629	if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
630	struct btrfs_file_extent_item *extent;
631	int found_type;
632	pos = key.offset;
633	extent = btrfs_item_ptr(leaf, slot,
634	struct btrfs_file_extent_item);
635	found_type = btrfs_file_extent_type(leaf, extent);
636	if (found_type == BTRFS_FILE_EXTENT_REG) {
637	u64 len = btrfs_file_extent_num_bytes(leaf,
638	extent);
639	u64 ds = btrfs_file_extent_disk_bytenr(leaf,
640	extent);
641	u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
642	extent);
643	u64 off = btrfs_file_extent_offset(leaf,
644	extent);
645	btrfs_insert_file_extent(trans, root,
646	inode->i_ino, pos,
647	ds, dl, len, off);
648	/* ds == 0 means there's a hole */
649	if (ds != 0) {
650	btrfs_inc_extent_ref(trans, root,
651	ds, dl,
652	root->root_key.objectid,
653	trans->transid,
654	inode->i_ino, pos);
655	}
656	pos = key.offset + len;
657	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
658	ret = dup_item_to_inode(trans, root, path,
659	leaf, slot, &key,
660	inode->i_ino);
661	if (ret)
662	goto out;
663	pos = key.offset + btrfs_item_size_nr(leaf,
664	slot);
665	}
666	} else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
667	ret = dup_item_to_inode(trans, root, path, leaf,
668	slot, &key, inode->i_ino);
669
670	if (ret)
671	goto out;
672	}
673	key.offset++;
674	btrfs_release_path(root, path);
675	}
676
677	ret = 0;
678	out:
679	btrfs_free_path(path);
680
681	inode->i_blocks = src->i_blocks;
682	i_size_write(inode, src->i_size);
683	btrfs_update_inode(trans, root, inode);
684
685	unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
686
687	btrfs_end_transaction(trans, root);
688	mutex_unlock(&root->fs_info->fs_mutex);
689
690	out_unlock:
691	mutex_unlock(&src->i_mutex);
692	mutex_unlock(&inode->i_mutex);
693	out_fput:
694	fput(src_file);
695	return ret;
696	}
697
698	/*
699	* there are many ways the trans_start and trans_end ioctls can lead
700	* to deadlocks. They should only be used by applications that
701	* basically own the machine, and have a very in depth understanding
702	* of all the possible deadlocks and enospc problems.
703	*/
704	long btrfs_ioctl_trans_start(struct file *file)
705	{
706	struct inode *inode = fdentry(file)->d_inode;
707	struct btrfs_root *root = BTRFS_I(inode)->root;
708	struct btrfs_trans_handle *trans;
709	int ret = 0;
710
df5b5520 CH	711	if (!capable(CAP_SYS_ADMIN))
	712	return -EPERM;
	713
f46b5a66 CH	714	mutex_lock(&root->fs_info->fs_mutex);
	715	if (file->private_data) {
	716	ret = -EINPROGRESS;
	717	goto out;
	718	}
	719	trans = btrfs_start_transaction(root, 0);
	720	if (trans)
	721	file->private_data = trans;
	722	else
	723	ret = -ENOMEM;
	724	/printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);/
	725	out:
	726	mutex_unlock(&root->fs_info->fs_mutex);
	727	return ret;
	728	}
	729
	730	/*
	731	* there are many ways the trans_start and trans_end ioctls can lead
	732	* to deadlocks. They should only be used by applications that
	733	* basically own the machine, and have a very in depth understanding
	734	* of all the possible deadlocks and enospc problems.
	735	*/
	736	long btrfs_ioctl_trans_end(struct file *file)
	737	{
	738	struct inode *inode = fdentry(file)->d_inode;
	739	struct btrfs_root *root = BTRFS_I(inode)->root;
	740	struct btrfs_trans_handle *trans;
	741	int ret = 0;
	742
	743	mutex_lock(&root->fs_info->fs_mutex);
	744	trans = file->private_data;
	745	if (!trans) {
	746	ret = -EINVAL;
	747	goto out;
	748	}
	749	btrfs_end_transaction(trans, root);
	750	file->private_data = 0;
	751	out:
	752	mutex_unlock(&root->fs_info->fs_mutex);
	753	return ret;
	754	}
	755
	756	long btrfs_ioctl(struct file *file, unsigned int
	757	cmd, unsigned long arg)
	758	{
	759	struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
	760
	761	switch (cmd) {
	762	case BTRFS_IOC_SNAP_CREATE:
	763	return btrfs_ioctl_snap_create(root, (void __user *)arg);
	764	case BTRFS_IOC_DEFRAG:
	765	return btrfs_ioctl_defrag(file);
	766	case BTRFS_IOC_RESIZE:
	767	return btrfs_ioctl_resize(root, (void __user *)arg);
	768	case BTRFS_IOC_ADD_DEV:
	769	return btrfs_ioctl_add_dev(root, (void __user *)arg);
	770	case BTRFS_IOC_RM_DEV:
	771	return btrfs_ioctl_rm_dev(root, (void __user *)arg);
	772	case BTRFS_IOC_BALANCE:
	773	return btrfs_balance(root->fs_info->dev_root);
	774	case BTRFS_IOC_CLONE:
	775	return btrfs_ioctl_clone(file, arg);
	776	case BTRFS_IOC_TRANS_START:
	777	return btrfs_ioctl_trans_start(file);
778	case BTRFS_IOC_TRANS_END:
779	return btrfs_ioctl_trans_end(file);
780	case BTRFS_IOC_SYNC:
781	btrfs_sync_fs(file->f_dentry->d_sb, 1);
782	return 0;
783	}
784
785	return -ENOTTY;
786	}