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         struct btrfs_fs_info *fs = root->fs_info;
  49         int ret;
  50
  51         ret = close_ctree(root);
  52         if (ret) {
  53                 printk("close ctree returns %d\n", ret);
  54         }
  55         btrfs_sysfs_del_super(fs);
  56         sb->s_fs_info = NULL;
  57 }
  58
  59 static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
  60 {
  61         struct inode * inode;
  62         struct dentry * root_dentry;
  63         struct btrfs_super_block *disk_super;
  64         struct btrfs_root *tree_root;
  65         struct btrfs_inode *bi;
  66         int err;
  67
  68         sb->s_maxbytes = MAX_LFS_FILESIZE;
  69         sb->s_magic = BTRFS_SUPER_MAGIC;
  70         sb->s_op = &btrfs_super_ops;
  71         sb->s_time_gran = 1;
  72
  73         tree_root = open_ctree(sb);
  74
  75         if (!tree_root || IS_ERR(tree_root)) {
  76                 printk("btrfs: open_ctree failed\n");
  77                 return -EIO;
  78         }
  79         sb->s_fs_info = tree_root;
  80         disk_super = tree_root->fs_info->disk_super;
  81         inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
  82                                   tree_root);
  83         bi = BTRFS_I(inode);
  84         bi->location.objectid = inode->i_ino;
  85         bi->location.offset = 0;
  86         bi->location.flags = 0;
  87         bi->root = tree_root;
  88
  89         btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
  90
  91         if (!inode) {
  92                 err = -ENOMEM;
  93                 goto fail_close;
  94         }
  95         if (inode->i_state & I_NEW) {
  96                 btrfs_read_locked_inode(inode);
  97                 unlock_new_inode(inode);
  98         }
  99
 100         root_dentry = d_alloc_root(inode);
 101         if (!root_dentry) {
 102                 iput(inode);
 103                 err = -ENOMEM;
 104                 goto fail_close;
 105         }
 106
 107         /* this does the super kobj at the same time */
 108         err = btrfs_sysfs_add_super(tree_root->fs_info);
 109         if (err)
 110                 goto fail_close;
 111
 112         sb->s_root = root_dentry;
 113         btrfs_transaction_queue_work(tree_root, HZ * 30);
 114         return 0;
 115
 116 fail_close:
 117         close_ctree(tree_root);
 118         return err;
 119 }
 120
 121 static int btrfs_sync_fs(struct super_block *sb, int wait)
 122 {
 123         struct btrfs_trans_handle *trans;
 124         struct btrfs_root *root;
 125         int ret;
 126         root = btrfs_sb(sb);
 127
 128         sb->s_dirt = 0;
 129         if (!wait) {
 130                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 131                 return 0;
 132         }
 133         btrfs_clean_old_snapshots(root);
 134         mutex_lock(&root->fs_info->fs_mutex);
 135         btrfs_defrag_dirty_roots(root->fs_info);
 136         trans = btrfs_start_transaction(root, 1);
 137         ret = btrfs_commit_transaction(trans, root);
 138         sb->s_dirt = 0;
 139         mutex_unlock(&root->fs_info->fs_mutex);
 140         return ret;
 141 }
 142
 143 static void btrfs_write_super(struct super_block *sb)
 144 {
 145         sb->s_dirt = 0;
 146 }
 147
 148 static int btrfs_get_sb(struct file_system_type *fs_type,
 149         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 150 {
 151         return get_sb_bdev(fs_type, flags, dev_name, data,
 152                            btrfs_fill_super, mnt);
 153 }
 154
 155 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 156 {
 157         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 158         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
 159
 160         buf->f_namelen = BTRFS_NAME_LEN;
 161         buf->f_blocks = btrfs_super_total_blocks(disk_super);
 162         buf->f_bfree = buf->f_blocks - btrfs_super_blocks_used(disk_super);
 163         buf->f_bavail = buf->f_bfree;
 164         buf->f_bsize = dentry->d_sb->s_blocksize;
 165         buf->f_type = BTRFS_SUPER_MAGIC;
 166         return 0;
 167 }
 168
 169 static struct file_system_type btrfs_fs_type = {
 170         .owner          = THIS_MODULE,
 171         .name           = "btrfs",
 172         .get_sb         = btrfs_get_sb,
 173         .kill_sb        = kill_block_super,
 174         .fs_flags       = FS_REQUIRES_DEV,
 175 };
 176
 177 static struct super_operations btrfs_super_ops = {
 178         .delete_inode   = btrfs_delete_inode,
 179         .put_super      = btrfs_put_super,
 180         .read_inode     = btrfs_read_locked_inode,
 181         .write_super    = btrfs_write_super,
 182         .sync_fs        = btrfs_sync_fs,
 183         .write_inode    = btrfs_write_inode,
 184         .dirty_inode    = btrfs_dirty_inode,
 185         .alloc_inode    = btrfs_alloc_inode,
 186         .destroy_inode  = btrfs_destroy_inode,
 187         .statfs         = btrfs_statfs,
 188 };
 189
 190 static int __init init_btrfs_fs(void)
 191 {
 192         int err;
 193
 194         err = btrfs_init_sysfs();
 195         if (err)
 196                 return err;
 197
 198         btrfs_init_transaction_sys();
 199         err = btrfs_init_cachep();
 200         if (err)
 201                 return err;
 202         extent_map_init();
 203         return register_filesystem(&btrfs_fs_type);
 204 }
 205
 206 static void __exit exit_btrfs_fs(void)
 207 {
 208         btrfs_exit_transaction_sys();
 209         btrfs_destroy_cachep();
 210         extent_map_exit();
 211         unregister_filesystem(&btrfs_fs_type);
 212         btrfs_exit_sysfs();
 213 }
 214
 215 module_init(init_btrfs_fs)
 216 module_exit(exit_btrfs_fs)
 217
 218 MODULE_LICENSE("GPL");