[deliverable/linux.git] / fs / btrfs / super.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/blkdev.h>
#include <linux/module.h>
#include <linux/buffer_head.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/mount.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/parser.h>
#include <linux/ctype.h>
#include <linux/namei.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
#include "xattr.h"

#define BTRFS_SUPER_MAGIC 0x9123683E

static struct super_operations btrfs_super_ops;

static void btrfs_put_super (struct super_block * sb)
{
	struct btrfs_root *root = btrfs_sb(sb);
	struct btrfs_fs_info *fs = root->fs_info;
	int ret;

	ret = close_ctree(root);
	if (ret) {
		printk("close ctree returns %d\n", ret);
	}
	btrfs_sysfs_del_super(fs);
	sb->s_fs_info = NULL;
}

enum {
	Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent,
	Opt_alloc_start, Opt_err,
};

static match_table_t tokens = {
	{Opt_subvol, "subvol=%s"},
	{Opt_nodatasum, "nodatasum"},
	{Opt_nodatacow, "nodatacow"},
	{Opt_max_extent, "max_extent=%s"},
	{Opt_alloc_start, "alloc_start=%s"},
	{Opt_err, NULL}
};

u64 btrfs_parse_size(char *str)
{
	u64 res;
	int mult = 1;
	char *end;
	char last;

	res = simple_strtoul(str, &end, 10);

	last = end[0];
	if (isalpha(last)) {
		last = tolower(last);
		switch (last) {
		case 'g':
			mult *= 1024;
		case 'm':
			mult *= 1024;
		case 'k':
			mult *= 1024;
		}
		res = res * mult;
	}
	return res;
}

static int parse_options (char * options,
			  struct btrfs_root *root,
			  char **subvol_name)
{
	char * p;
	struct btrfs_fs_info *info = NULL;
	substring_t args[MAX_OPT_ARGS];

	if (!options)
		return 1;

	/*
	 * strsep changes the string, duplicate it because parse_options
	 * gets called twice
	 */
	options = kstrdup(options, GFP_NOFS);
	if (!options)
		return -ENOMEM;

	if (root)
		info = root->fs_info;

	while ((p = strsep (&options, ",")) != NULL) {
		int token;
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_subvol:
			if (subvol_name) {
				*subvol_name = match_strdup(&args[0]);
			}
			break;
		case Opt_nodatasum:
			if (info) {
				printk("btrfs: setting nodatacsum\n");
				btrfs_set_opt(info->mount_opt, NODATASUM);
			}
			break;
		case Opt_nodatacow:
			if (info) {
				printk("btrfs: setting nodatacow\n");
				btrfs_set_opt(info->mount_opt, NODATACOW);
				btrfs_set_opt(info->mount_opt, NODATASUM);
			}
			break;
		case Opt_max_extent:
			if (info) {
				char *num = match_strdup(&args[0]);
				if (num) {
					info->max_extent =
						btrfs_parse_size(num);
					kfree(num);

					info->max_extent = max_t(u64,
							 info->max_extent,
							 root->sectorsize);
					printk("btrfs: max_extent at %Lu\n",
					       info->max_extent);
				}
			}
			break;
		case Opt_alloc_start:
			if (info) {
				char *num = match_strdup(&args[0]);
				if (num) {
					info->alloc_start =
						btrfs_parse_size(num);
					kfree(num);
					printk("btrfs: allocations start at "
					       "%Lu\n", info->alloc_start);
				}
			}
			break;
		default:
			break;
		}
	}
	kfree(options);
	return 1;
}

static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
{
	struct inode * inode;
	struct dentry * root_dentry;
	struct btrfs_super_block *disk_super;
	struct btrfs_root *tree_root;
	struct btrfs_inode *bi;
	int err;

	sb->s_maxbytes = MAX_LFS_FILESIZE;
	sb->s_magic = BTRFS_SUPER_MAGIC;
	sb->s_op = &btrfs_super_ops;
	sb->s_xattr = btrfs_xattr_handlers;
	sb->s_time_gran = 1;

	tree_root = open_ctree(sb);

	if (!tree_root || IS_ERR(tree_root)) {
		printk("btrfs: open_ctree failed\n");
		return -EIO;
	}
	sb->s_fs_info = tree_root;
	disk_super = &tree_root->fs_info->super_copy;
	inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
				  tree_root);
	bi = BTRFS_I(inode);
	bi->location.objectid = inode->i_ino;
	bi->location.offset = 0;
	bi->root = tree_root;

	btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);

	if (!inode) {
		err = -ENOMEM;
		goto fail_close;
	}
	if (inode->i_state & I_NEW) {
		btrfs_read_locked_inode(inode);
		unlock_new_inode(inode);
	}

	root_dentry = d_alloc_root(inode);
	if (!root_dentry) {
		iput(inode);
		err = -ENOMEM;
		goto fail_close;
	}

	parse_options((char *)data, tree_root, NULL);

	/* this does the super kobj at the same time */
	err = btrfs_sysfs_add_super(tree_root->fs_info);
	if (err)
		goto fail_close;

	sb->s_root = root_dentry;
	btrfs_transaction_queue_work(tree_root, HZ * 30);
	return 0;

fail_close:
	close_ctree(tree_root);
	return err;
}

static int btrfs_sync_fs(struct super_block *sb, int wait)
{
	struct btrfs_trans_handle *trans;
	struct btrfs_root *root;
	int ret;
	root = btrfs_sb(sb);

	sb->s_dirt = 0;
	if (!wait) {
		filemap_flush(root->fs_info->btree_inode->i_mapping);
		return 0;
	}
	btrfs_clean_old_snapshots(root);
	mutex_lock(&root->fs_info->fs_mutex);
	btrfs_defrag_dirty_roots(root->fs_info);
	trans = btrfs_start_transaction(root, 1);
	ret = btrfs_commit_transaction(trans, root);
	sb->s_dirt = 0;
	mutex_unlock(&root->fs_info->fs_mutex);
	return ret;
}

static void btrfs_write_super(struct super_block *sb)
{
	sb->s_dirt = 0;
}

/*
 * This is almost a copy of get_sb_bdev in fs/super.c.
 * We need the local copy to allow direct mounting of
 * subvolumes, but this could be easily integrated back
 * into the generic version.  --hch
 */

/* start copy & paste */
static int set_bdev_super(struct super_block *s, void *data)
{
	s->s_bdev = data;
	s->s_dev = s->s_bdev->bd_dev;
	return 0;
}

static int test_bdev_super(struct super_block *s, void *data)
{
	return (void *)s->s_bdev == data;
}

int btrfs_get_sb_bdev(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data,
	int (*fill_super)(struct super_block *, void *, int),
	struct vfsmount *mnt, const char *subvol)
{
	struct block_device *bdev = NULL;
	struct super_block *s;
	struct dentry *root;
	int error = 0;

	bdev = open_bdev_excl(dev_name, flags, fs_type);
	if (IS_ERR(bdev))
		return PTR_ERR(bdev);

	/*
	 * once the super is inserted into the list by sget, s_umount
	 * will protect the lockfs code from trying to start a snapshot
	 * while we are mounting
	 */
	down(&bdev->bd_mount_sem);
	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
	up(&bdev->bd_mount_sem);
	if (IS_ERR(s))
		goto error_s;

	if (s->s_root) {
		if ((flags ^ s->s_flags) & MS_RDONLY) {
			up_write(&s->s_umount);
			deactivate_super(s);
			error = -EBUSY;
			goto error_bdev;
		}

		close_bdev_excl(bdev);
	} else {
		char b[BDEVNAME_SIZE];

		s->s_flags = flags;
		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
		sb_set_blocksize(s, block_size(bdev));
		error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
		if (error) {
			up_write(&s->s_umount);
			deactivate_super(s);
			goto error;
		}

		s->s_flags |= MS_ACTIVE;
	}

	if (subvol) {
		root = lookup_one_len(subvol, s->s_root, strlen(subvol));
		if (IS_ERR(root)) {
			up_write(&s->s_umount);
			deactivate_super(s);
			error = PTR_ERR(root);
			goto error;
		}
		if (!root->d_inode) {
			dput(root);
			up_write(&s->s_umount);
			deactivate_super(s);
			error = -ENXIO;
			goto error;
		}
	} else {
		root = dget(s->s_root);
	}

	mnt->mnt_sb = s;
	mnt->mnt_root = root;
	return 0;

error_s:
	error = PTR_ERR(s);
error_bdev:
	close_bdev_excl(bdev);
error:
	return error;
}
/* end copy & paste */

static int btrfs_get_sb(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
	int ret;
	char *subvol_name = NULL;

	parse_options((char *)data, NULL, &subvol_name);
	ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data,
			btrfs_fill_super, mnt,
			subvol_name ? subvol_name : "default");
	if (subvol_name)
		kfree(subvol_name);
	return ret;
}

static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct btrfs_root *root = btrfs_sb(dentry->d_sb);
	struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
	int bits = dentry->d_sb->s_blocksize_bits;

	buf->f_namelen = BTRFS_NAME_LEN;
	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
	buf->f_bfree = buf->f_blocks -
		(btrfs_super_bytes_used(disk_super) >> bits);
	buf->f_bavail = buf->f_bfree;
	buf->f_bsize = dentry->d_sb->s_blocksize;
	buf->f_type = BTRFS_SUPER_MAGIC;
	return 0;
}

static struct file_system_type btrfs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "btrfs",
	.get_sb		= btrfs_get_sb,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};

static struct super_operations btrfs_super_ops = {
	.delete_inode	= btrfs_delete_inode,
	.put_super	= btrfs_put_super,
	.read_inode	= btrfs_read_locked_inode,
	.write_super	= btrfs_write_super,
	.sync_fs	= btrfs_sync_fs,
	.write_inode	= btrfs_write_inode,
	.dirty_inode	= btrfs_dirty_inode,
	.alloc_inode	= btrfs_alloc_inode,
	.destroy_inode	= btrfs_destroy_inode,
	.statfs		= btrfs_statfs,
};

static int __init init_btrfs_fs(void)
{
	int err;

	err = btrfs_init_sysfs();
	if (err)
		return err;

	btrfs_init_transaction_sys();
	err = btrfs_init_cachep();
	if (err)
		goto free_transaction_sys;
	err = extent_map_init();
	if (err)
		goto free_cachep;

	err = register_filesystem(&btrfs_fs_type);
	if (err)
		goto free_extent_map;
	return 0;

free_extent_map:
	extent_map_exit();
free_cachep:
	btrfs_destroy_cachep();
free_transaction_sys:
	btrfs_exit_transaction_sys();
	btrfs_exit_sysfs();
	return err;
}

static void __exit exit_btrfs_fs(void)
{
	btrfs_exit_transaction_sys();
	btrfs_destroy_cachep();
	extent_map_exit();
	unregister_filesystem(&btrfs_fs_type);
	btrfs_exit_sysfs();
}

module_init(init_btrfs_fs)
module_exit(exit_btrfs_fs)

MODULE_LICENSE("GPL");
Commit	Line	Data
6cbd5570 CM	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
4b82d6e4	19	#include <linux/blkdev.h>
2e635a27	20	#include <linux/module.h>
e20d96d6	21	#include <linux/buffer_head.h>
2e635a27 CM	22	#include <linux/fs.h>
	23	#include <linux/pagemap.h>
	24	#include <linux/highmem.h>
	25	#include <linux/time.h>
	26	#include <linux/init.h>
	27	#include <linux/string.h>
	28	#include <linux/smp_lock.h>
	29	#include <linux/backing-dev.h>
4b82d6e4	30	#include <linux/mount.h>
dee26a9f	31	#include <linux/mpage.h>
75dfe396 CM	32	#include <linux/swap.h>
75dfe396 CM	33	#include <linux/writeback.h>
8fd17795	34	#include <linux/statfs.h>
08607c1b	35	#include <linux/compat.h>
95e05289	36	#include <linux/parser.h>
c59f8951	37	#include <linux/ctype.h>
6da6abae	38	#include <linux/namei.h>
2e635a27	39	#include "ctree.h"
e20d96d6	40	#include "disk-io.h"
d5719762	41	#include "transaction.h"
2c90e5d6	42	#include "btrfs_inode.h"
c5739bba	43	#include "ioctl.h"
3a686375	44	#include "print-tree.h"
5103e947	45	#include "xattr.h"
2e635a27	46
5f39d397	47	#define BTRFS_SUPER_MAGIC 0x9123683E
f254e52c	48
39279cc3	49	static struct super_operations btrfs_super_ops;
75dfe396	50
39279cc3	51	static void btrfs_put_super (struct super_block * sb)
b18c6685	52	{
39279cc3	53	struct btrfs_root *root = btrfs_sb(sb);
58176a96	54	struct btrfs_fs_info *fs = root->fs_info;
b18c6685	55	int ret;
b18c6685	56
39279cc3 CM	57	ret = close_ctree(root);
	58	if (ret) {
	59	printk("close ctree returns %d\n", ret);
75dfe396	60	}
58176a96	61	btrfs_sysfs_del_super(fs);
39279cc3	62	sb->s_fs_info = NULL;
75dfe396 CM	63	}
75dfe396 CM	64
95e05289	65	enum {
8f662a76 CM	66	Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent,
8f662a76 CM	67	Opt_alloc_start, Opt_err,
95e05289 CM	68	};
	69
	70	static match_table_t tokens = {
	71	{Opt_subvol, "subvol=%s"},
b6cda9bc	72	{Opt_nodatasum, "nodatasum"},
be20aa9d	73	{Opt_nodatacow, "nodatacow"},
c59f8951	74	{Opt_max_extent, "max_extent=%s"},
8f662a76	75	{Opt_alloc_start, "alloc_start=%s"},
95e05289 CM	76	{Opt_err, NULL}
	77	};
	78
edbd8d4e	79	u64 btrfs_parse_size(char *str)
c59f8951	80	{
edbd8d4e	81	u64 res;
c59f8951 CM	82	int mult = 1;
	83	char *end;
	84	char last;
	85
	86	res = simple_strtoul(str, &end, 10);
	87
	88	last = end[0];
	89	if (isalpha(last)) {
	90	last = tolower(last);
	91	switch (last) {
	92	case 'g':
	93	mult *= 1024;
	94	case 'm':
	95	mult *= 1024;
	96	case 'k':
	97	mult *= 1024;
	98	}
	99	res = res * mult;
	100	}
	101	return res;
	102	}
	103
95e05289 CM	104	static int parse_options (char * options,
	105	struct btrfs_root *root,
	106	char **subvol_name)
	107	{
	108	char * p;
b6cda9bc	109	struct btrfs_fs_info *info = NULL;
95e05289	110	substring_t args[MAX_OPT_ARGS];
b6cda9bc	111
95e05289 CM	112	if (!options)
	113	return 1;
	114
be20aa9d CM	115	/*
	116	* strsep changes the string, duplicate it because parse_options
	117	* gets called twice
	118	*/
	119	options = kstrdup(options, GFP_NOFS);
	120	if (!options)
	121	return -ENOMEM;
	122
	123	if (root)
	124	info = root->fs_info;
	125
95e05289 CM	126	while ((p = strsep (&options, ",")) != NULL) {
	127	int token;
	128	if (!*p)
	129	continue;
	130
	131	token = match_token(p, tokens, args);
	132	switch (token) {
	133	case Opt_subvol:
be20aa9d	134	if (subvol_name) {
b6cda9bc	135	*subvol_name = match_strdup(&args[0]);
be20aa9d	136	}
b6cda9bc CM	137	break;
b6cda9bc CM	138	case Opt_nodatasum:
be20aa9d CM	139	if (info) {
be20aa9d CM	140	printk("btrfs: setting nodatacsum\n");
b6cda9bc	141	btrfs_set_opt(info->mount_opt, NODATASUM);
be20aa9d CM	142	}
	143	break;
	144	case Opt_nodatacow:
	145	if (info) {
	146	printk("btrfs: setting nodatacow\n");
	147	btrfs_set_opt(info->mount_opt, NODATACOW);
	148	btrfs_set_opt(info->mount_opt, NODATASUM);
	149	}
95e05289	150	break;
c59f8951 CM	151	case Opt_max_extent:
	152	if (info) {
	153	char *num = match_strdup(&args[0]);
	154	if (num) {
edbd8d4e CM	155	info->max_extent =
edbd8d4e CM	156	btrfs_parse_size(num);
c59f8951 CM	157	kfree(num);
	158
	159	info->max_extent = max_t(u64,
	160	info->max_extent,
	161	root->sectorsize);
	162	printk("btrfs: max_extent at %Lu\n",
	163	info->max_extent);
	164	}
	165	}
	166	break;
8f662a76 CM	167	case Opt_alloc_start:
	168	if (info) {
	169	char *num = match_strdup(&args[0]);
	170	if (num) {
	171	info->alloc_start =
	172	btrfs_parse_size(num);
	173	kfree(num);
	174	printk("btrfs: allocations start at "
	175	"%Lu\n", info->alloc_start);
	176	}
	177	}
	178	break;
95e05289	179	default:
be20aa9d	180	break;
95e05289 CM	181	}
95e05289 CM	182	}
be20aa9d	183	kfree(options);
95e05289 CM	184	return 1;
	185	}
	186
39279cc3	187	static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
75dfe396	188	{
39279cc3 CM	189	struct inode * inode;
	190	struct dentry * root_dentry;
	191	struct btrfs_super_block *disk_super;
	192	struct btrfs_root *tree_root;
	193	struct btrfs_inode *bi;
	194	int err;
a429e513	195
39279cc3 CM	196	sb->s_maxbytes = MAX_LFS_FILESIZE;
	197	sb->s_magic = BTRFS_SUPER_MAGIC;
	198	sb->s_op = &btrfs_super_ops;
5103e947	199	sb->s_xattr = btrfs_xattr_handlers;
39279cc3	200	sb->s_time_gran = 1;
a429e513	201
39279cc3	202	tree_root = open_ctree(sb);
6567e837	203
39279cc3 CM	204	if (!tree_root \|\| IS_ERR(tree_root)) {
	205	printk("btrfs: open_ctree failed\n");
	206	return -EIO;
a429e513	207	}
39279cc3	208	sb->s_fs_info = tree_root;
5f39d397	209	disk_super = &tree_root->fs_info->super_copy;
39279cc3 CM	210	inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
	211	tree_root);
	212	bi = BTRFS_I(inode);
	213	bi->location.objectid = inode->i_ino;
	214	bi->location.offset = 0;
39279cc3	215	bi->root = tree_root;
b888db2b	216
39279cc3	217	btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
a429e513	218
39279cc3	219	if (!inode) {
6567e837	220	err = -ENOMEM;
39279cc3	221	goto fail_close;
f254e52c	222	}
39279cc3 CM	223	if (inode->i_state & I_NEW) {
	224	btrfs_read_locked_inode(inode);
	225	unlock_new_inode(inode);
f254e52c	226	}
f254e52c	227
39279cc3 CM	228	root_dentry = d_alloc_root(inode);
	229	if (!root_dentry) {
	230	iput(inode);
	231	err = -ENOMEM;
	232	goto fail_close;
f254e52c	233	}
58176a96	234
b6cda9bc CM	235	parse_options((char *)data, tree_root, NULL);
b6cda9bc CM	236
58176a96 JB	237	/* this does the super kobj at the same time */
	238	err = btrfs_sysfs_add_super(tree_root->fs_info);
	239	if (err)
	240	goto fail_close;
	241
39279cc3 CM	242	sb->s_root = root_dentry;
39279cc3 CM	243	btrfs_transaction_queue_work(tree_root, HZ * 30);
2619ba1f	244	return 0;
39279cc3 CM	245
	246	fail_close:
	247	close_ctree(tree_root);
	248	return err;
2619ba1f CM	249	}
2619ba1f CM	250
39279cc3	251	static int btrfs_sync_fs(struct super_block *sb, int wait)
c5739bba CM	252	{
c5739bba CM	253	struct btrfs_trans_handle *trans;
39279cc3	254	struct btrfs_root *root;
c5739bba	255	int ret;
39279cc3	256	root = btrfs_sb(sb);
2619ba1f	257
39279cc3 CM	258	sb->s_dirt = 0;
	259	if (!wait) {
	260	filemap_flush(root->fs_info->btree_inode->i_mapping);
	261	return 0;
	262	}
e9d0b13b	263	btrfs_clean_old_snapshots(root);
c5739bba	264	mutex_lock(&root->fs_info->fs_mutex);
e9d0b13b	265	btrfs_defrag_dirty_roots(root->fs_info);
c5739bba	266	trans = btrfs_start_transaction(root, 1);
c5739bba	267	ret = btrfs_commit_transaction(trans, root);
39279cc3	268	sb->s_dirt = 0;
c5739bba	269	mutex_unlock(&root->fs_info->fs_mutex);
54aa1f4d	270	return ret;
2c90e5d6 CM	271	}
2c90e5d6 CM	272
39279cc3	273	static void btrfs_write_super(struct super_block *sb)
2c90e5d6	274	{
39279cc3	275	sb->s_dirt = 0;
2c90e5d6 CM	276	}
2c90e5d6 CM	277
4b82d6e4 Y	278	/*
	279	* This is almost a copy of get_sb_bdev in fs/super.c.
	280	* We need the local copy to allow direct mounting of
	281	* subvolumes, but this could be easily integrated back
	282	* into the generic version. --hch
	283	*/
	284
	285	/* start copy & paste */
	286	static int set_bdev_super(struct super_block s, void data)
	287	{
	288	s->s_bdev = data;
	289	s->s_dev = s->s_bdev->bd_dev;
	290	return 0;
	291	}
	292
	293	static int test_bdev_super(struct super_block s, void data)
	294	{
	295	return (void *)s->s_bdev == data;
	296	}
	297
	298	int btrfs_get_sb_bdev(struct file_system_type *fs_type,
	299	int flags, const char dev_name, void data,
	300	int (fill_super)(struct super_block , void *, int),
	301	struct vfsmount mnt, const char subvol)
	302	{
	303	struct block_device *bdev = NULL;
	304	struct super_block *s;
	305	struct dentry *root;
	306	int error = 0;
	307
	308	bdev = open_bdev_excl(dev_name, flags, fs_type);
	309	if (IS_ERR(bdev))
	310	return PTR_ERR(bdev);
	311
	312	/*
	313	* once the super is inserted into the list by sget, s_umount
	314	* will protect the lockfs code from trying to start a snapshot
	315	* while we are mounting
	316	*/
	317	down(&bdev->bd_mount_sem);
	318	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
	319	up(&bdev->bd_mount_sem);
	320	if (IS_ERR(s))
	321	goto error_s;
	322
	323	if (s->s_root) {
	324	if ((flags ^ s->s_flags) & MS_RDONLY) {
	325	up_write(&s->s_umount);
	326	deactivate_super(s);
	327	error = -EBUSY;
	328	goto error_bdev;
	329	}
	330
	331	close_bdev_excl(bdev);
	332	} else {
	333	char b[BDEVNAME_SIZE];
	334
	335	s->s_flags = flags;
	336	strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
	337	sb_set_blocksize(s, block_size(bdev));
	338	error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
	339	if (error) {
	340	up_write(&s->s_umount);
	341	deactivate_super(s);
342	goto error;
343	}
344
345	s->s_flags \|= MS_ACTIVE;
346	}
347
348	if (subvol) {
349	root = lookup_one_len(subvol, s->s_root, strlen(subvol));
350	if (IS_ERR(root)) {
351	up_write(&s->s_umount);
352	deactivate_super(s);
353	error = PTR_ERR(root);
354	goto error;
355	}
356	if (!root->d_inode) {
357	dput(root);
358	up_write(&s->s_umount);
359	deactivate_super(s);
360	error = -ENXIO;
361	goto error;
362	}
363	} else {
364	root = dget(s->s_root);
365	}
366
367	mnt->mnt_sb = s;
368	mnt->mnt_root = root;
369	return 0;
370
371	error_s:
372	error = PTR_ERR(s);
373	error_bdev:
374	close_bdev_excl(bdev);
375	error:
376	return error;
377	}
378	/* end copy & paste */
379
2e635a27	380	static int btrfs_get_sb(struct file_system_type *fs_type,
95e05289	381	int flags, const char dev_name, void data, struct vfsmount *mnt)
2e635a27	382	{
4b82d6e4	383	int ret;
95e05289	384	char *subvol_name = NULL;
4b82d6e4	385
95e05289	386	parse_options((char *)data, NULL, &subvol_name);
4b82d6e4 Y	387	ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data,
	388	btrfs_fill_super, mnt,
	389	subvol_name ? subvol_name : "default");
c59f8951 CM	390	if (subvol_name)
c59f8951 CM	391	kfree(subvol_name);
4b82d6e4	392	return ret;
2e635a27 CM	393	}
2e635a27 CM	394
8fd17795 CM	395	static int btrfs_statfs(struct dentry dentry, struct kstatfs buf)
	396	{
	397	struct btrfs_root *root = btrfs_sb(dentry->d_sb);
4b52dff6	398	struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
db94535d	399	int bits = dentry->d_sb->s_blocksize_bits;
8fd17795 CM	400
8fd17795 CM	401	buf->f_namelen = BTRFS_NAME_LEN;
db94535d CM	402	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
	403	buf->f_bfree = buf->f_blocks -
	404	(btrfs_super_bytes_used(disk_super) >> bits);
8fd17795 CM	405	buf->f_bavail = buf->f_bfree;
	406	buf->f_bsize = dentry->d_sb->s_blocksize;
	407	buf->f_type = BTRFS_SUPER_MAGIC;
	408	return 0;
	409	}
b5133862	410
2e635a27 CM	411	static struct file_system_type btrfs_fs_type = {
	412	.owner = THIS_MODULE,
	413	.name = "btrfs",
	414	.get_sb = btrfs_get_sb,
	415	.kill_sb = kill_block_super,
	416	.fs_flags = FS_REQUIRES_DEV,
	417	};
	418
e20d96d6	419	static struct super_operations btrfs_super_ops = {
134e9731	420	.delete_inode = btrfs_delete_inode,
e20d96d6 CM	421	.put_super = btrfs_put_super,
e20d96d6 CM	422	.read_inode = btrfs_read_locked_inode,
d5719762 CM	423	.write_super = btrfs_write_super,
d5719762 CM	424	.sync_fs = btrfs_sync_fs,
4730a4bc	425	.write_inode = btrfs_write_inode,
b5133862	426	.dirty_inode = btrfs_dirty_inode,
2c90e5d6 CM	427	.alloc_inode = btrfs_alloc_inode,
2c90e5d6 CM	428	.destroy_inode = btrfs_destroy_inode,
8fd17795	429	.statfs = btrfs_statfs,
e20d96d6 CM	430	};
e20d96d6 CM	431
2e635a27 CM	432	static int __init init_btrfs_fs(void)
2e635a27 CM	433	{
2c90e5d6	434	int err;
58176a96 JB	435
	436	err = btrfs_init_sysfs();
	437	if (err)
	438	return err;
	439
08607c1b	440	btrfs_init_transaction_sys();
39279cc3	441	err = btrfs_init_cachep();
2c90e5d6	442	if (err)
2f4cbe64 WB	443	goto free_transaction_sys;
	444	err = extent_map_init();
	445	if (err)
	446	goto free_cachep;
	447
	448	err = register_filesystem(&btrfs_fs_type);
	449	if (err)
	450	goto free_extent_map;
	451	return 0;
	452
	453	free_extent_map:
	454	extent_map_exit();
	455	free_cachep:
	456	btrfs_destroy_cachep();
	457	free_transaction_sys:
	458	btrfs_exit_transaction_sys();
	459	btrfs_exit_sysfs();
	460	return err;
2e635a27 CM	461	}
	462
	463	static void __exit exit_btrfs_fs(void)
	464	{
08607c1b	465	btrfs_exit_transaction_sys();
39279cc3	466	btrfs_destroy_cachep();
a52d9a80	467	extent_map_exit();
2e635a27	468	unregister_filesystem(&btrfs_fs_type);
58176a96	469	btrfs_exit_sysfs();
2e635a27 CM	470	}
	471
	472	module_init(init_btrfs_fs)
	473	module_exit(exit_btrfs_fs)
	474
	475	MODULE_LICENSE("GPL");