static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *root_inode;
struct dentry *root_dentry;
int rc = 0;
struct hypfs_sb_info *sbi;
sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
mutex_init(&sbi->lock);
sbi->uid = current->uid;
sbi->gid = current->gid;
sb->s_fs_info = sbi;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = HYPFS_MAGIC;
sb->s_op = &hypfs_s_ops;
if (hypfs_parse_options(data, sb)) {
rc = -EINVAL;
goto err_alloc;
}
root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
if (!root_inode) {
rc = -ENOMEM;
goto err_alloc;
}
root_inode->i_op = &simple_dir_inode_operations;
root_inode->i_fop = &simple_dir_operations;
root_dentry = d_alloc_root(root_inode);
if (!root_dentry) {
iput(root_inode);
rc = -ENOMEM;
goto err_alloc;
}
if (MACHINE_IS_VM)
rc = hypfs_vm_create_files(sb, root_dentry);
else
rc = hypfs_diag_create_files(sb, root_dentry);
if (rc)
goto err_tree;
sbi->update_file = hypfs_create_update_file(sb, root_dentry);
if (IS_ERR(sbi->update_file)) {
rc = PTR_ERR(sbi->update_file);
goto err_tree;
}
hypfs_update_update(sb);
sb->s_root = root_dentry;
printk(KERN_INFO "hypfs: Hypervisor filesystem mounted\n");
return 0;
err_tree:
hypfs_delete_tree(root_dentry);
d_genocide(root_dentry);
dput(root_dentry);
err_alloc:
kfree(sbi);
return rc;
}
static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t offset)
{
int rc;
struct super_block *sb;
struct hypfs_sb_info *fs_info;
size_t count = iov_length(iov, nr_segs);
sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
fs_info = sb->s_fs_info;
/*
* Currently we only allow one update per second for two reasons:
* 1. diag 204 is VERY expensive
* 2. If several processes do updates in parallel and then read the
* hypfs data, the likelihood of collisions is reduced, if we restrict
* the minimum update interval. A collision occurs, if during the
* data gathering of one process another process triggers an update
* If the first process wants to ensure consistent data, it has
* to restart data collection in this case.
*/
mutex_lock(&fs_info->lock);
if (fs_info->last_update == get_seconds()) {
rc = -EBUSY;
goto out;
}
hypfs_delete_tree(sb->s_root);
if (MACHINE_IS_VM)
rc = hypfs_vm_create_files(sb, sb->s_root);
else
rc = hypfs_diag_create_files(sb, sb->s_root);
if (rc) {
pr_err("Updating the hypfs tree failed\n");
hypfs_delete_tree(sb->s_root);
goto out;
}
hypfs_update_update(sb);
rc = count;
out:
mutex_unlock(&fs_info->lock);
return rc;
}
static void hypfs_kill_super(struct super_block *sb)
{
struct hypfs_sb_info *sb_info = sb->s_fs_info;
if (sb->s_root)
hypfs_delete_tree(sb->s_root);
if (sb_info->update_file)
hypfs_remove(sb_info->update_file);
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
kill_litter_super(sb);
}