vops.c File Reference

ext2: the vnode operations: reading and writing files, directories, making nodes, truncating, and attributes. More...

#include <ext2.h>
#include <core/time.h>
#include <fs/iobuf.h>

Go to the source code of this file.

Functions
ssize_t	ext2_read (struct vnode *node, off_t offset, struct iobuf *io)
	Reads from a file.
ssize_t	ext2_write (struct vnode *node, off_t offset, struct iobuf *io)
	Writes to a file, which grows if the write goes past its end.
ssize_t	ext2_readdir (struct vnode *dir, off_t offset, struct dirent *dirent)
	Reads a directory's entry at an offset; unused entries don't count.
int	ext2_trunc (struct vnode *inode, off_t len)
	Changes a file's length.
int	ext2_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	ext2_finddir (struct vnode *dir, const char *fn, struct dirent *dirent)
	Finds the entry of a directory that has a name.
int	ext2_vget (struct vnode *super, ino_t ino, struct vnode **ref)
	Gets the vnode of an inode, by its number.
int	ext2_setattr (struct vnode *vnode)
	Stores a vnode's attributes (mode, owner, times) in its inode.

Detailed Description

ext2: the vnode operations: reading and writing files, directories, making nodes, truncating, and attributes.

Removing, linking and renaming are in remove.c.

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

ext2_finddir()

int ext2_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, -ENOENT, or a negative errno

Definition at line 414 of file vops.c.

References ext2_dentry_find(), ext2_finddir(), ext2_inode_read(), vnode::ino, and vnode::p.

Referenced by ext2_finddir().

ext2_read()

ssize_t ext2_read	(	struct vnode *	node,
		off_t	offset,
		struct iobuf *	io )

Reads from a file.

Parameters

node	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 23 of file vops.c.

References ext2_inode::blocks, ext2::bs, ext2_inode::direct_pointer, ext2_inode_block_read(), ext2_inode_read(), ext2_read(), vnode::ino, iobuf_out(), kfree(), kmalloc(), MIN, ext2_inode::mode, vnode::p, iobuf::resid, and ext2_inode::size.

Referenced by ext2_read().

ext2_readdir()

ssize_t ext2_readdir	(	struct vnode *	dir,
		off_t	offset,
		struct dirent *	dirent )

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

Parameters

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

Returns

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

Definition at line 174 of file vops.c.

References ext2::bs, ext2_inode_block_read(), ext2_inode_read(), ext2_readdir(), ext2_dentry::ino, vnode::ino, kfree(), kmalloc(), ext2_dentry::length, memcpy(), ext2_inode::mode, vnode::mode, ext2_dentry::name, vnode::p, ext2_dentry::size, and ext2_inode::size.

Referenced by ext2_readdir().

ext2_setattr()

int ext2_setattr

(

struct vnode *

vnode

)

Stores a vnode's attributes (mode, owner, times) in its inode.

Parameters

vnode

the vnode

Returns

0, or an I/O error

Definition at line 456 of file vops.c.

References ext2_inode::atime, vnode::atime, ext2_inode::ctime, vnode::ctime, ext2_inode_read(), ext2_inode_write(), ext2_setattr(), ext2_inode::gid, vnode::gid, vnode::ino, ext2_inode::mode, vnode::mode, ext2_inode::mtime, vnode::mtime, vnode::p, timespec::tv_sec, ext2_inode::uid, and vnode::uid.

Referenced by ext2_setattr().

ext2_trunc()

int ext2_trunc	(	struct vnode *	inode,
		off_t	len )

Changes a file's length.

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

Parameters

inode	the file
len	the new length, in bytes

Returns

0, -ENOMEM, or an I/O error

Definition at line 252 of file vops.c.

References ext2::bs, ext2_blocks_free(), ext2_inode_block_read(), ext2_inode_block_write(), ext2_inode_read(), ext2_inode_sync(), ext2_inode_write(), ext2_trunc(), vnode::ino, kfree(), kmalloc(), memset(), vnode::p, ext2_inode::size, and vnode::size.

Referenced by ext2_trunc(), and ext2_write().

ext2_vget()

int ext2_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 443 of file vops.c.

References ext2_inode_build(), ext2_vget(), and vnode::p.

Referenced by ext2_vget().

ext2_vmknod()

int ext2_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 a block with 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, -EEXIST, -ENOSPC, -ENOMEM, or an I/O error

Definition at line 312 of file vops.c.

References ext2_inode::atime, ext2::bs, ext2_inode::ctime, DEV, DEV_MAJOR, DEV_MINOR, ext2_inode::direct_pointer, ext2_group::directories_count, ext2_bgd_table_rewrite(), ext2_dentry_create(), ext2_dentry_find(), EXT2_DENTRY_TYPE_DIR, ext2_inode_alloc(), ext2_inode_block_write(), ext2_inode_build(), ext2_inode_discard(), ext2_inode_read(), ext2_inode_sync(), ext2_inode_write(), ext2_vmknod(), ext2::filetype, gettime(), ext2_inode::gid, uio::gid, ext2_superblock::ginodes, ext2::groups, ext2_dentry::ino, vnode::ino, kfree(), kmalloc(), ext2_dentry::length, M_ZERO, memcpy(), memset(), ext2_inode::mode, ext2_inode::mtime, ext2_dentry::name, ext2_inode::nlink, vnode::nlink, vnode::p, ext2_dentry::size, ext2_inode::size, ext2::superblock, timespec::tv_sec, ext2_dentry::type, ext2_inode::uid, and uio::uid.

Referenced by ext2_vmknod().

ext2_write()

ssize_t ext2_write	(	struct vnode *	node,
		off_t	offset,
		struct iobuf *	io )

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

A short symbolic link keeps its target in the inode itself.

Parameters

node	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 83 of file vops.c.

References ext2_inode::blocks, ext2::bs, ext2_inode::direct_pointer, ext2_inode_block_read(), ext2_inode_block_write(), ext2_inode_read(), ext2_inode_write(), ext2_trunc(), ext2_write(), vnode::ino, iobuf_in(), kfree(), kmalloc(), LOG_DEBUG, MAX, MIN, vnode::mode, vnode::p, iobuf::resid, ext2_inode::size, and vnode::size.

Referenced by ext2_write().