static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
struct dentry **root_dentry)
{
struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
struct nilfs_root *root;
int ret;
down_read(&nilfs->ns_segctor_sem);
ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
up_read(&nilfs->ns_segctor_sem);
if (ret < 0) {
ret = (ret == -ENOENT) ? -EINVAL : ret;
goto out;
} else if (!ret) {
printk(KERN_ERR "NILFS: The specified checkpoint is "
"not a snapshot (checkpoint number=%llu).\n",
(unsigned long long)cno);
ret = -EINVAL;
goto out;
}
ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
if (ret) {
printk(KERN_ERR "NILFS: error loading snapshot "
"(checkpoint number=%llu).\n",
(unsigned long long)cno);
goto out;
}
ret = nilfs_get_root_dentry(s, root, root_dentry);
nilfs_put_root(root);
out:
return ret;
}
static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
struct dentry **root_dentry)
{
struct the_nilfs *nilfs = s->s_fs_info;
struct nilfs_root *root;
int ret;
mutex_lock(&nilfs->ns_snapshot_mount_mutex);
down_read(&nilfs->ns_segctor_sem);
ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
up_read(&nilfs->ns_segctor_sem);
if (ret < 0) {
ret = (ret == -ENOENT) ? -EINVAL : ret;
goto out;
} else if (!ret) {
nilfs_msg(s, KERN_ERR,
"The specified checkpoint is not a snapshot (checkpoint number=%llu)",
(unsigned long long)cno);
ret = -EINVAL;
goto out;
}
ret = nilfs_attach_checkpoint(s, cno, false, &root);
if (ret) {
nilfs_msg(s, KERN_ERR,
"error %d while loading snapshot (checkpoint number=%llu)",
ret, (unsigned long long)cno);
goto out;
}
ret = nilfs_get_root_dentry(s, root, root_dentry);
nilfs_put_root(root);
out:
mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
return ret;
}
/**
* nilfs_fill_super() - initialize a super block instance
* @sb: super_block
* @data: mount options
* @silent: silent mode flag
* @nilfs: the_nilfs struct
*
* This function is called exclusively by nilfs->ns_mount_mutex.
* So, the recovery process is protected from other simultaneous mounts.
*/
static int
nilfs_fill_super(struct super_block *sb, void *data, int silent,
struct the_nilfs *nilfs)
{
struct nilfs_sb_info *sbi;
struct inode *root;
__u64 cno;
int err;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
get_nilfs(nilfs);
sbi->s_nilfs = nilfs;
sbi->s_super = sb;
atomic_set(&sbi->s_count, 1);
err = init_nilfs(nilfs, sbi, (char *)data);
if (err)
goto failed_sbi;
spin_lock_init(&sbi->s_inode_lock);
INIT_LIST_HEAD(&sbi->s_dirty_files);
INIT_LIST_HEAD(&sbi->s_list);
/*
* Following initialization is overlapped because
* nilfs_sb_info structure has been cleared at the beginning.
* But we reserve them to keep our interest and make ready
* for the future change.
*/
get_random_bytes(&sbi->s_next_generation,
sizeof(sbi->s_next_generation));
spin_lock_init(&sbi->s_next_gen_lock);
sb->s_op = &nilfs_sops;
sb->s_export_op = &nilfs_export_ops;
sb->s_root = NULL;
sb->s_time_gran = 1;
sb->s_bdi = nilfs->ns_bdi;
err = load_nilfs(nilfs, sbi);
if (err)
goto failed_sbi;
cno = nilfs_last_cno(nilfs);
if (sb->s_flags & MS_RDONLY) {
if (nilfs_test_opt(sbi, SNAPSHOT)) {
down_read(&nilfs->ns_segctor_sem);
err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
sbi->s_snapshot_cno);
up_read(&nilfs->ns_segctor_sem);
if (err < 0) {
if (err == -ENOENT)
err = -EINVAL;
goto failed_sbi;
}
if (!err) {
printk(KERN_ERR
"NILFS: The specified checkpoint is "
"not a snapshot "
"(checkpoint number=%llu).\n",
(unsigned long long)sbi->s_snapshot_cno);
err = -EINVAL;
goto failed_sbi;
}
cno = sbi->s_snapshot_cno;
}
}
err = nilfs_attach_checkpoint(sbi, cno);
if (err) {
printk(KERN_ERR "NILFS: error loading a checkpoint"
" (checkpoint number=%llu).\n", (unsigned long long)cno);
goto failed_sbi;
}
if (!(sb->s_flags & MS_RDONLY)) {
err = nilfs_attach_segment_constructor(sbi);
if (err)
goto failed_checkpoint;
}
root = nilfs_iget(sb, NILFS_ROOT_INO);
if (IS_ERR(root)) {
printk(KERN_ERR "NILFS: get root inode failed\n");
err = PTR_ERR(root);
goto failed_segctor;
}
if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
iput(root);
printk(KERN_ERR "NILFS: corrupt root inode.\n");
err = -EINVAL;
goto failed_segctor;
}
sb->s_root = d_alloc_root(root);
if (!sb->s_root) {
iput(root);
printk(KERN_ERR "NILFS: get root dentry failed\n");
err = -ENOMEM;
goto failed_segctor;
}
if (!(sb->s_flags & MS_RDONLY)) {
down_write(&nilfs->ns_sem);
nilfs_setup_super(sbi);
up_write(&nilfs->ns_sem);
}
down_write(&nilfs->ns_super_sem);
if (!nilfs_test_opt(sbi, SNAPSHOT))
nilfs->ns_current = sbi;
up_write(&nilfs->ns_super_sem);
return 0;
failed_segctor:
nilfs_detach_segment_constructor(sbi);
failed_checkpoint:
nilfs_detach_checkpoint(sbi);
failed_sbi:
put_nilfs(nilfs);
sb->s_fs_info = NULL;
nilfs_put_sbinfo(sbi);
return err;
}