rpc_pipe.c

Linux Kernel 2.6.9 for OMAP1710

	if (path[0] == '\0')
		return -ENOENT;
	if (rpc_get_mount()) {
		printk(KERN_WARNING "%s: %s failed to mount "
			       "pseudofilesystem \n", __FILE__, __FUNCTION__);
		return -ENODEV;
	}
	nd->mnt = mntget(rpc_mount);
	nd->dentry = dget(rpc_mount->mnt_root);
	nd->last_type = LAST_ROOT;
	nd->flags = LOOKUP_PARENT;
	nd->depth = 0;

	if (path_walk(path, nd)) {
		printk(KERN_WARNING "%s: %s failed to find path %s\n",
				__FILE__, __FUNCTION__, path);
		rpc_put_mount();
		return -ENOENT;
	}
	return 0;
}

static void
rpc_release_path(struct nameidata *nd)
{
	path_release(nd);
	rpc_put_mount();
}

static struct inode *
rpc_get_inode(struct super_block *sb, int mode)
{
	struct inode *inode = new_inode(sb);
	if (!inode)
		return NULL;
	inode->i_mode = mode;
	inode->i_uid = inode->i_gid = 0;
	inode->i_blksize = PAGE_CACHE_SIZE;
	inode->i_blocks = 0;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	switch(mode & S_IFMT) {
		case S_IFDIR:
			inode->i_fop = &simple_dir_operations;
			inode->i_op = &simple_dir_inode_operations;
			inode->i_nlink++;
		default:
			break;
	}
	return inode;
}

/*
 * FIXME: This probably has races.
 */
static void
rpc_depopulate(struct dentry *parent)
{
	struct inode *dir = parent->d_inode;
	struct list_head *pos, *next;
	struct dentry *dentry, *dvec[10];
	int n = 0;

	down(&dir->i_sem);
repeat:
	spin_lock(&dcache_lock);
	list_for_each_safe(pos, next, &parent->d_subdirs) {
		dentry = list_entry(pos, struct dentry, d_child);
		spin_lock(&dentry->d_lock);
		if (!d_unhashed(dentry)) {
			dget_locked(dentry);
			__d_drop(dentry);
			spin_unlock(&dentry->d_lock);
			dvec[n++] = dentry;
			if (n == ARRAY_SIZE(dvec))
				break;
		} else
			spin_unlock(&dentry->d_lock);
	}
	spin_unlock(&dcache_lock);
	if (n) {
		do {
			dentry = dvec[--n];
			if (dentry->d_inode) {
				rpc_close_pipes(dentry->d_inode);
				rpc_inode_setowner(dentry->d_inode, NULL);
				simple_unlink(dir, dentry);
			}
			dput(dentry);
		} while (n);
		goto repeat;
	}
	up(&dir->i_sem);
}

static int
rpc_populate(struct dentry *parent,
		struct rpc_filelist *files,
		int start, int eof)
{
	struct inode *inode, *dir = parent->d_inode;
	void *private = RPC_I(dir)->private;
	struct qstr name;
	struct dentry *dentry;
	int mode, i;

	down(&dir->i_sem);
	for (i = start; i < eof; i++) {
		name.name = files[i].name;
		name.len = strlen(name.name);
		name.hash = full_name_hash(name.name, name.len);
		dentry = d_alloc(parent, &name);
		if (!dentry)
			goto out_bad;
		mode = files[i].mode;
		inode = rpc_get_inode(dir->i_sb, mode);
		if (!inode) {
			dput(dentry);
			goto out_bad;
		}
		inode->i_ino = i;
		if (files[i].i_fop)
			inode->i_fop = files[i].i_fop;
		if (private)
			rpc_inode_setowner(inode, private);
		if (S_ISDIR(mode))
			dir->i_nlink++;
		d_add(dentry, inode);
	}
	up(&dir->i_sem);
	return 0;
out_bad:
	up(&dir->i_sem);
	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
			__FILE__, __FUNCTION__, parent->d_name.name);
	return -ENOMEM;
}

static int
__rpc_mkdir(struct inode *dir, struct dentry *dentry)
{
	struct inode *inode;

	inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
	if (!inode)
		goto out_err;
	inode->i_ino = iunique(dir->i_sb, 100);
	d_instantiate(dentry, inode);
	dir->i_nlink++;
	inode_dir_notify(dir, DN_CREATE);
	rpc_get_mount();
	return 0;
out_err:
	printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
			__FILE__, __FUNCTION__, dentry->d_name.name);
	return -ENOMEM;
}

static int
__rpc_rmdir(struct inode *dir, struct dentry *dentry)
{
	int error;

	shrink_dcache_parent(dentry);
	if (dentry->d_inode) {
		rpc_close_pipes(dentry->d_inode);
		rpc_inode_setowner(dentry->d_inode, NULL);
	}
	if ((error = simple_rmdir(dir, dentry)) != 0)
		return error;
	if (!error) {
		inode_dir_notify(dir, DN_DELETE);
		d_drop(dentry);
		rpc_put_mount();
	}
	return 0;
}

struct dentry *
rpc_lookup_negative(char *path, struct nameidata *nd)
{
	struct dentry *dentry;
	struct inode *dir;
	int error;

	if ((error = rpc_lookup_parent(path, nd)) != 0)
		return ERR_PTR(error);
	dir = nd->dentry->d_inode;
	down(&dir->i_sem);
	dentry = lookup_hash(&nd->last, nd->dentry);
	if (IS_ERR(dentry))
		goto out_err;
	if (dentry->d_inode) {
		dput(dentry);
		dentry = ERR_PTR(-EEXIST);
		goto out_err;
	}
	return dentry;
out_err:
	up(&dir->i_sem);
	rpc_release_path(nd);
	return dentry;
}


struct dentry *
rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
{
	struct nameidata nd;
	struct dentry *dentry;
	struct inode *dir;
	int error;

	dentry = rpc_lookup_negative(path, &nd);
	if (IS_ERR(dentry))
		return dentry;
	dir = nd.dentry->d_inode;
	if ((error = __rpc_mkdir(dir, dentry)) != 0)
		goto err_dput;
	RPC_I(dentry->d_inode)->private = rpc_client;
	error = rpc_populate(dentry, authfiles,
			RPCAUTH_info, RPCAUTH_EOF);
	if (error)
		goto err_depopulate;
out:
	up(&dir->i_sem);
	rpc_release_path(&nd);
	return dentry;
err_depopulate:
	rpc_depopulate(dentry);
	__rpc_rmdir(dir, dentry);
err_dput:
	dput(dentry);
	printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
			__FILE__, __FUNCTION__, path, error);
	dentry = ERR_PTR(error);
	goto out;
}

int
rpc_rmdir(char *path)
{
	struct nameidata nd;
	struct dentry *dentry;
	struct inode *dir;
	int error;

	if ((error = rpc_lookup_parent(path, &nd)) != 0)
		return error;
	dir = nd.dentry->d_inode;
	down(&dir->i_sem);
	dentry = lookup_hash(&nd.last, nd.dentry);
	if (IS_ERR(dentry)) {
		error = PTR_ERR(dentry);
		goto out_release;
	}
	rpc_depopulate(dentry);
	error = __rpc_rmdir(dir, dentry);
	dput(dentry);
out_release:
	up(&dir->i_sem);
	rpc_release_path(&nd);
	return error;
}

struct dentry *
rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
{
	struct nameidata nd;
	struct dentry *dentry;
	struct inode *dir, *inode;
	struct rpc_inode *rpci;

	dentry = rpc_lookup_negative(path, &nd);
	if (IS_ERR(dentry))
		return dentry;
	dir = nd.dentry->d_inode;
	inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
	if (!inode)
		goto err_dput;
	inode->i_ino = iunique(dir->i_sb, 100);
	inode->i_fop = &rpc_pipe_fops;
	d_instantiate(dentry, inode);
	rpci = RPC_I(inode);
	rpci->private = private;
	rpci->flags = flags;
	rpci->ops = ops;
	inode_dir_notify(dir, DN_CREATE);
out:
	up(&dir->i_sem);
	rpc_release_path(&nd);
	return dentry;
err_dput:
	dput(dentry);
	dentry = ERR_PTR(-ENOMEM);
	printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
			__FILE__, __FUNCTION__, path, -ENOMEM);
	goto out;
}

int
rpc_unlink(char *path)
{
	struct nameidata nd;
	struct dentry *dentry;
	struct inode *dir;
	int error;

	if ((error = rpc_lookup_parent(path, &nd)) != 0)
		return error;
	dir = nd.dentry->d_inode;
	down(&dir->i_sem);
	dentry = lookup_hash(&nd.last, nd.dentry);
	if (IS_ERR(dentry)) {
		error = PTR_ERR(dentry);
		goto out_release;
	}
	d_drop(dentry);
	if (dentry->d_inode) {
		rpc_close_pipes(dentry->d_inode);
		rpc_inode_setowner(dentry->d_inode, NULL);
		error = simple_unlink(dir, dentry);
	}
	dput(dentry);
	inode_dir_notify(dir, DN_DELETE);
out_release:
	up(&dir->i_sem);
	rpc_release_path(&nd);
	return error;
}

/*
 * populate the filesystem
 */
static struct super_operations s_ops = {
	.alloc_inode	= rpc_alloc_inode,
	.destroy_inode	= rpc_destroy_inode,
	.statfs		= simple_statfs,
};

#define RPCAUTH_GSSMAGIC 0x67596969

static int
rpc_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *inode;
	struct dentry *root;

	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = RPCAUTH_GSSMAGIC;
	sb->s_op = &s_ops;

	inode = rpc_get_inode(sb, S_IFDIR | 0755);
	if (!inode)
		return -ENOMEM;
	root = d_alloc_root(inode);
	if (!root) {
		iput(inode);
		return -ENOMEM;
	}
	if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
		goto out;
	sb->s_root = root;
	return 0;
out:
	d_genocide(root);
	dput(root);
	return -ENOMEM;
}

static struct super_block *
rpc_get_sb(struct file_system_type *fs_type,
		int flags, const char *dev_name, void *data)
{
	return get_sb_single(fs_type, flags, data, rpc_fill_super);
}

static struct file_system_type rpc_pipe_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "rpc_pipefs",
	.get_sb		= rpc_get_sb,
	.kill_sb	= kill_litter_super,
};

static void
init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
	struct rpc_inode *rpci = (struct rpc_inode *) foo;

	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
	    SLAB_CTOR_CONSTRUCTOR) {
		inode_init_once(&rpci->vfs_inode);
		rpci->private = NULL;
		rpci->nreaders = 0;
		rpci->nwriters = 0;
		INIT_LIST_HEAD(&rpci->in_upcall);
		INIT_LIST_HEAD(&rpci->pipe);
		rpci->pipelen = 0;
		init_waitqueue_head(&rpci->waitq);
		INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
		rpci->ops = NULL;
	}
}

int register_rpc_pipefs(void)
{
	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
                                             sizeof(struct rpc_inode),
                                             0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
                                             init_once, NULL);
	if (!rpc_inode_cachep)
		return -ENOMEM;
	register_filesystem(&rpc_pipe_fs_type);
	return 0;
}

void unregister_rpc_pipefs(void)
{
	if (kmem_cache_destroy(rpc_inode_cachep))
		printk(KERN_WARNING "RPC: unable to free inode cache\n");
	unregister_filesystem(&rpc_pipe_fs_type);
}