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/*
* Copyright (c) 2025 Ian Marco Moffett and L5 engineers
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _OS_VNODE_H_
#define _OS_VNODE_H_ 1
#include <sys/types.h>
#include <sys/atomic.h>
/* Forward declarations */
struct vnode;
struct vop;
/*
* Valid vnode types
*
* @VTYPE_NONE: Vnode is yet to be assigned a type
* @VTYPE_FILE: Vnode references a file
* @VTYPE_DIR: Vnode references a directory
* @__N_VTYPE: Number of valid nodes on the system
*/
typedef enum {
VTYPE_NONE,
VTYPE_FILE,
VTYPE_DIR,
__N_VTYPE
} vtype_t;
/*
* Represents the arguments used in a vnode lookup
* operation
*
* @name: Path componenet to look up
* @dirvp: Current directory
* @vpp: Resulting vnode pointer is written here
*/
struct vop_lookup_args {
const char *name;
struct vnode *dirvp;
struct vnode **vpp;
};
/*
* Represents VOP data that can be used to read
* or write a file, etc
*
* @data: Buffer containing I/O data
* @len: Length of buffer
* @vp: Current vnode
*/
struct vop_rw_data {
void *data;
size_t len;
struct vnode *vp;
};
/*
* Represents operations that can be performed on
* a specific vnode. These are implemented as callbacks
*/
struct vop {
int(*lookup)(struct vop_lookup_args *args);
ssize_t(*write)(struct vop_rw_data *data);
};
/*
* Abstract representation of a referenced filesystem object
* such as a file, directory, network file object,
* etc.
*
* [F]: Set up by filesystem
* [V] Set up by VFS
* [F/V]: Both F and V
*
* @refcount: How many objects have a reference
* @type: Vnode type [F/V]
* @vops: Vnode operations hooks [F]
* @data: Filesystem specific data [F]
*/
struct vnode {
int refcount;
vtype_t type;
struct vop *vops;
void *data;
};
#define vnode_ref(VP) (atomic_inc_int(&(VP)->refcount))
/*
* Allocate a new vnode
*
* @resp: Result pointer is written here
* @type: Vnode type
* @flags: Optional flags
*
* Return zero on success, otherwise a less than zero
* on failure.
*/
int vfs_valloc(struct vnode **resp, vtype_t type, int flags);
/*
* Deallocate / release a vnode
*
* @vp: Vnode to release
* @flags: Optional flags
*
* Returns zero on success, otherwise less than zero
* on failure.
*/
int vfs_vrel(struct vnode *vp, int flags);
/*
* Wrapper for the vnode write callback
*
* @vp: Vnode to write to
* @data: Data to write
* @len: Length of bytes to write
*
* Returns the number of bytes written on success, otherwise
* a less than zero value on failure.
*/
ssize_t vop_write(struct vnode *vp, char *data, size_t len);
#endif /* !_OS_VNODE_H_ */
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