Technical Reference: Kernel and Subsystems, Volume 1

gfsadd Kernel Service

Purpose

Adds a file system type to the gfs table.

Syntax

#include <sys/types.h>
#include <sys/errno.h>
int gfsadd ( gfsno, gfsp)
int gfsno;
struct gfs *gfsp;

Parameters

gfsno	Specifies the file system number. This small integer value is either defined in the /usr/include/sys/vmount.h file or a user-defined number of the same order.
gfsp	Points to the file system description structure.

Description

The gfsadd kernel service is used during configuration of a file system. The configuration routine for a file system invokes the gfsadd kernel service with a gfs structure. This structure describes the file system type.

The gfs structure type is defined in the /usr/include/sys/gfs.h file. The gfs structure must have the following fields filled in:

Field	Description
`gfs_type`	Specifies the integer type value. The predefined types are listed in the /usr/include/sys/vmount.h file.
`gfs_name`	Specifies the character string name of the file system. The maximum length of this field is 16 bytes. Shorter names must be null-padded.
`gfs_flags`	Specifies the flags that define the capabilities of the file system. The following flag values are defined: GFS_SYS5DIR File system that uses the System V-type directory structure. GFS_REMOTE File system is remote (ie. NFS). GFS_FUMNT File system supports forced unmount. GFS_NOUMASK File system applies umask when creating new objects. GFS_VERSION4 File system supports AIX Version 4 V-node interface. GFS_VERSION42 File system supports AIX 4.2 V-node interface. (new vnode op: vn_seek) GFS_VERSION421 File system supports AIX 4.2.1 V-node interface.(new vnode ops: vn_sync_range, vn_create_attr, vn_finfo, vn_map_lloff, vn_readdir_eofp, vn_rdwr_attr)) GFS_VERSION43 File system supports AIX 4.3 V-node interface. (new file flag for vn_sync_range:FMSYNC)
`gfs_ops`	Specifies the array of pointers to vfs operation implementations.
`gn_ops`	Specifies the array of pointers to v-node operation implementations.

The file system description structure can also specify:

`gfs_init`	Points to an initialization routine to be called by the gfsadd kernel service. This field must be null if no initialization routine is to be called.
`gfs_data`	Points to file system private data.

Execution Environment

The gfsadd kernel service can be called from the process environment only.

Return Values

0	Indicates successful completion.
EBUSY	Indicates that the file system type has already been installed.
EINVAL	Indicates that the gfsno value is larger than the system-defined maximum. The system-defined maximum is indicated in the /usr/include/sys/vmount.h file.

Related Information

The gfsdel kernel service.