fs/btrfs/super.c

   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/module.h>
  20 #include <linux/buffer_head.h>
  21 #include <linux/fs.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/highmem.h>
  24 #include <linux/time.h>
  25 #include <linux/init.h>
  26 #include <linux/string.h>
  27 #include <linux/smp_lock.h>
  28 #include <linux/backing-dev.h>
  29 #include <linux/mpage.h>
  30 #include <linux/swap.h>
  31 #include <linux/writeback.h>
  32 #include <linux/statfs.h>
  33 #include <linux/compat.h>
  34 #include "ctree.h"
  35 #include "disk-io.h"
  36 #include "transaction.h"
  37 #include "btrfs_inode.h"
  38 #include "ioctl.h"
  39 #include "print-tree.h"
  40
  41 #define BTRFS_SUPER_MAGIC 0x9123682E
  42
  43 static struct super_operations btrfs_super_ops;
  44
  45 static void btrfs_put_super (struct super_block * sb)
  46 {
  47         struct btrfs_root *root = btrfs_sb(sb);
  48         int ret;
  49
  50         ret = close_ctree(root);
  51         if (ret) {
  52                 printk("close ctree returns %d\n", ret);
  53         }
  54         sb->s_fs_info = NULL;
  55 }
  56
  57 static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
  58 {
  59         struct inode * inode;
  60         struct dentry * root_dentry;
  61         struct btrfs_super_block *disk_super;
  62         struct btrfs_root *tree_root;
  63         struct btrfs_inode *bi;
  64         int err;
  65
  66         sb->s_maxbytes = MAX_LFS_FILESIZE;
  67         sb->s_magic = BTRFS_SUPER_MAGIC;
  68         sb->s_op = &btrfs_super_ops;
  69         sb->s_time_gran = 1;
  70
  71         tree_root = open_ctree(sb);
  72
  73         if (!tree_root || IS_ERR(tree_root)) {
  74                 printk("btrfs: open_ctree failed\n");
  75                 return -EIO;
  76         }
  77         sb->s_fs_info = tree_root;
  78         disk_super = tree_root->fs_info->disk_super;
  79         inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
  80                                   tree_root);
  81         bi = BTRFS_I(inode);
  82         bi->location.objectid = inode->i_ino;
  83         bi->location.offset = 0;
  84         bi->location.flags = 0;
  85         bi->root = tree_root;
  86         btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
  87
  88         if (!inode) {
  89                 err = -ENOMEM;
  90                 goto fail_close;
  91         }
  92         if (inode->i_state & I_NEW) {
  93                 btrfs_read_locked_inode(inode);
  94                 unlock_new_inode(inode);
  95         }
  96
  97         root_dentry = d_alloc_root(inode);
  98         if (!root_dentry) {
  99                 iput(inode);
 100                 err = -ENOMEM;
 101                 goto fail_close;
 102         }
 103         sb->s_root = root_dentry;
 104         btrfs_transaction_queue_work(tree_root, HZ * 30);
 105         return 0;
 106
 107 fail_close:
 108         close_ctree(tree_root);
 109         return err;
 110 }
 111
 112 static int btrfs_sync_fs(struct super_block *sb, int wait)
 113 {
 114         struct btrfs_trans_handle *trans;
 115         struct btrfs_root *root;
 116         int ret;
 117         root = btrfs_sb(sb);
 118
 119         sb->s_dirt = 0;
 120         if (!wait) {
 121                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 122                 return 0;
 123         }
 124         mutex_lock(&root->fs_info->fs_mutex);
 125         trans = btrfs_start_transaction(root, 1);
 126         ret = btrfs_commit_transaction(trans, root);
 127         sb->s_dirt = 0;
 128         mutex_unlock(&root->fs_info->fs_mutex);
 129         return ret;
 130 }
 131
 132 static void btrfs_write_super(struct super_block *sb)
 133 {
 134         sb->s_dirt = 0;
 135 }
 136
 137 static int btrfs_get_sb(struct file_system_type *fs_type,
 138         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 139 {
 140         return get_sb_bdev(fs_type, flags, dev_name, data,
 141                            btrfs_fill_super, mnt);
 142 }
 143
 144 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 145 {
 146         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 147         struct btrfs_super_block *disk_super = root->fs_info->disk_super;
 148
 149         buf->f_namelen = BTRFS_NAME_LEN;
 150         buf->f_blocks = btrfs_super_total_blocks(disk_super);
 151         buf->f_bfree = buf->f_blocks - btrfs_super_blocks_used(disk_super);
 152         buf->f_bavail = buf->f_bfree;
 153         buf->f_bsize = dentry->d_sb->s_blocksize;
 154         buf->f_type = BTRFS_SUPER_MAGIC;
 155         return 0;
 156 }
 157
 158 static struct file_system_type btrfs_fs_type = {
 159         .owner          = THIS_MODULE,
 160         .name           = "btrfs",
 161         .get_sb         = btrfs_get_sb,
 162         .kill_sb        = kill_block_super,
 163         .fs_flags       = FS_REQUIRES_DEV,
 164 };
 165
 166 static struct super_operations btrfs_super_ops = {
 167         .delete_inode   = btrfs_delete_inode,
 168         .put_super      = btrfs_put_super,
 169         .read_inode     = btrfs_read_locked_inode,
 170         .write_super    = btrfs_write_super,
 171         .sync_fs        = btrfs_sync_fs,
 172         .write_inode    = btrfs_write_inode,
 173         .dirty_inode    = btrfs_dirty_inode,
 174         .alloc_inode    = btrfs_alloc_inode,
 175         .destroy_inode  = btrfs_destroy_inode,
 176         .statfs         = btrfs_statfs,
 177 };
 178
 179 static int __init init_btrfs_fs(void)
 180 {
 181         int err;
 182         btrfs_init_transaction_sys();
 183         err = btrfs_init_cachep();
 184         if (err)
 185                 return err;
 186         return register_filesystem(&btrfs_fs_type);
 187 }
 188
 189 static void __exit exit_btrfs_fs(void)
 190 {
 191         btrfs_exit_transaction_sys();
 192         btrfs_destroy_cachep();
 193         unregister_filesystem(&btrfs_fs_type);
 194 }
 195
 196 module_init(init_btrfs_fs)
 197 module_exit(exit_btrfs_fs)
 198
 199 MODULE_LICENSE("GPL");