Implements control operations for a file system.
int vfs_cntl (vfsp, cmd, arg, argsize, crp) struct vfs *vfsp; int cmd; caddr_t arg; unsigned long argsize; struct ucred *crp;
The vfs_cntl entry point is invoked by the logical file system to request various control operations on the underlying file system. A file system implementation can define file system-specific cmd parameter values and corresponding control functions. The cmd parameter for these functions should have a minimum value of 32768. These control operations can be issued with the fscntl subroutine.
Note: The only system-supported control operation is FS_EXTENDFS. This operation increases the file system size and accepts an arg parameter that specifies the new size. The FS_EXTENDFS operation ignores the argsize parameter.
The vfs_cntl entry point can be called from the process environment only.
0 | Indicates success. |
Non-zero return values are returned from the /usr/include/sys/errno.h file to indicate failure. Typical values include:
The fscntl subroutine.
Virtual File System Overview, Virtual File System Kernel Extensions Overview, Logical File System Overview, Understanding Virtual Nodes (V-nodes) in AIX Kernel Extensions and Device Support Programming Concepts.