vops.c File Reference

minix: the vnode operations: reading and writing files, directories, making nodes, and truncating. More...

#include <minix.h>
#include <fs/iobuf.h>

Go to the source code of this file.

Functions
ssize_t	minix_read (struct vnode *vnode, off_t offset, struct iobuf *io)
	Reads from a file.
ssize_t	minix_write (struct vnode *vnode, off_t offset, struct iobuf *io)
	Writes to a file, which grows if the write goes past its end.
ssize_t	minix_readdir (struct vnode *dir, off_t off, struct dirent *dirent)
	Reads a directory's entry at an offset; unused entries don't count.
int	minix_vmknod (struct vnode *dir, const char *fn, mode_t mode, dev_t dev, struct uio *uio, struct vnode **ref)
	Makes a node in a directory: a new inode, and an entry for it.
int	minix_finddir (struct vnode *dir, const char *fn, struct dirent *dirent)
	Finds the entry of a directory that has a name.
int	minix_vget (struct vnode *super, ino_t ino, struct vnode **ref)
	Gets the vnode of an inode, by its number.
int	minix_trunc (struct vnode *vnode, off_t len)
	Changes a file's length.

Detailed Description

minix: the vnode operations: reading and writing files, directories, making nodes, and truncating.

A file's data moves one block at a time through a kernel buffer: the block's piece of the iobuf is copied into or out of it.

Definition in file vops.c.

Function Documentation

minix_finddir()

int minix_finddir	(	struct vnode *	dir,
		const char *	fn,
		struct dirent *	dirent )

Finds the entry of a directory that has a name.

Only the entry's inode number is filled in.

Parameters

dir	the directory
fn	the name
dirent	if not NULL, the entry

Returns

0, -ENOTDIR if dir isn't a directory, -ENOENT, or an I/O error

Definition at line 324 of file vops.c.

References vnode::ino, minix_dentry_find(), minix_finddir(), minix_inode_read(), minix_inode::mode, and vnode::p.

Referenced by minix_finddir().

minix_read()

ssize_t minix_read	(	struct vnode *	vnode,
		off_t	offset,
		struct iobuf *	io )

Reads from a file.

Parameters

vnode	the file
offset	where to read from
io	where the data goes, and how much is wanted

Returns

the number of bytes read (0 at or past the end), or a negative errno if nothing was read

Definition at line 21 of file vops.c.

References minix::bs, vnode::ino, iobuf_out(), kfree(), kmalloc(), MIN, minix_inode_block_read(), minix_inode_read(), minix_read(), vnode::p, iobuf::resid, and minix_inode::size.

Referenced by minix_read().

minix_readdir()

ssize_t minix_readdir	(	struct vnode *	dir,
		off_t	off,
		struct dirent *	dirent )

Reads a directory's entry at an offset; unused entries don't count.

Parameters

dir	the directory
off	which entry
dirent	the entry, filled in

Returns

1 if an entry was read, 0 past the last one, -ENOTDIR, or an I/O error

Definition at line 151 of file vops.c.

References minix::bs, minix::dentry_size, minix_dentry::ino, vnode::ino, memcpy(), minix_inode_block_read(), minix_inode_read(), minix_readdir(), minix_inode::mode, vnode::mode, minix_dentry::name, minix::name_len, vnode::p, and minix_inode::size.

Referenced by minix_readdir().

minix_trunc()

int minix_trunc	(	struct vnode *	vnode,
		off_t	len )

Changes a file's length.

A file that grows reads zeros past its old end; a file that shrinks frees its zones past the new end.

Parameters

vnode	the file
len	the new length, in bytes

Returns

0, -ENOMEM, or an I/O error

Definition at line 380 of file vops.c.

References minix::bs, vnode::ino, kfree(), kmalloc(), memset(), minix_inode_block_read(), minix_inode_block_write(), minix_inode_read(), minix_inode_sync(), minix_inode_write(), minix_trunc(), minix_zones_free(), vnode::p, minix_inode::size, and vnode::size.

Referenced by minix_trunc(), and minix_write().

minix_vget()

int minix_vget	(	struct vnode *	super,
		ino_t	ino,
		struct vnode **	ref )

Gets the vnode of an inode, by its number.

Parameters

super	any vnode of the filesystem
ino	the inode number
ref	if not NULL, set to the vnode

Returns

0, or a negative errno

Definition at line 363 of file vops.c.

References minix_inode_build(), minix_vget(), and vnode::p.

Referenced by minix_vget().

minix_vmknod()

int minix_vmknod	(	struct vnode *	dir,
		const char *	fn,
		mode_t	mode,
		dev_t	dev,
		struct uio *	uio,
		struct vnode **	ref )

Makes a node in a directory: a new inode, and an entry for it.

A new directory gets its . and .. entries.

Parameters

dir	the directory
fn	the new node's name
mode	its type (S_IF*) and permissions
dev	its device number, for a device node
uio	who is asking (the owner)
ref	if not NULL, set to the new vnode

Returns

0, -EINVAL for an empty name, -ENOTDIR, -EEXIST, -ENOSPC, or an I/O error

Definition at line 216 of file vops.c.

References minix::bs, minix::dentry_size, DEV, DEV_MAJOR, DEV_MINOR, minix_inode::gid, uio::gid, minix_dentry::ino, vnode::ino, memcpy(), memset(), minix_dentry_create(), minix_dentry_find(), minix_inode_alloc(), minix_inode_block_write(), minix_inode_build(), minix_inode_free(), minix_inode_read(), minix_inode_write(), minix_vmknod(), minix_zones_free(), minix_inode::mode, minix_dentry::name, vnode::nlink, minix_inode::nlinks, vnode::p, minix_inode::size, minix_inode::uid, uio::uid, and minix_inode::zones.

Referenced by minix_vmknod().

minix_write()

ssize_t minix_write	(	struct vnode *	vnode,
		off_t	offset,
		struct iobuf *	io )

Writes to a file, which grows if the write goes past its end.

Parameters

vnode	the file
offset	where to write
io	the data, and how much of it

Returns

the number of bytes written, or a negative errno if nothing was written

Definition at line 75 of file vops.c.

References minix::bs, vnode::ino, iobuf_in(), kfree(), kmalloc(), MAX, MIN, minix_inode_block_read(), minix_inode_block_write(), minix_inode_read(), minix_inode_write(), minix_trunc(), minix_write(), vnode::p, iobuf::resid, minix_inode::size, and vnode::size.

Referenced by minix_write().