VFSSUBR(9) BSD Kernel Developer's Manual VFSSUBR(9)NAME
vfssubr, vfs_getnewfsid, vfs_getvfs, vfs_export, vfs_showexport,
vfs_export_lookup, vfs_setpublicfs, vfs_mountedon, vfs_mountroot,
vfs_unmountall, vfs_busy, vfs_unbusy, vfs_mountalloc, vfs_rootmountalloc,
vfs_shutdown, vfs_attach, vfs_detach, vfs_reinit, vfs_getopsbyname,
vfs_suspend, vfs_resume — high-level interface to kernel file system
interface
SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/vnode.h>
void
vfs_getnewfsid(struct mount *mp);
struct mount *
vfs_getvfs(fsid_t *fsid);
int
vfs_export_lookup(struct mount *mp, struct netexport *nep,
struct export_args *argp);
int
vfs_setpublicfs(struct mount *mp, struct netexport *nep,
struct export_args *argp);
int
vfs_mountedon(struct vnode *vp);
int
vfs_mountroot(void);
void
vfs_unmountall(struct lwp *l);
int
vfs_busy(struct mount *mp, int flags, struct simplelock *interlkp);
void
vfs_unbusy(struct mount *mp);
struct mount *
vfs_mountalloc(struct vfsops *vfs, struct vnode *vp);
int
vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp);
void
vfs_shutdown(void);
int
vfs_attach(struct vfsops *vfs);
int
vfs_detach(struct vfsops *vfs);
void
vfs_reinit(void);
struct vfsops *
vfs_getopsbyname(const char *name);
int
vfs_suspend(struct mount *mp, int nowait);
void
vfs_resume(struct mount *mp);
DESCRIPTION
The high-level functions described in this page are the interface to the
kernel file system interface (VFS).
FUNCTIONSvfs_getnewfsid(mp)
Get a new unique file system id type for the file system speci‐
fied by the mount structure mp. The file system id type is
stored in mp->mnt_stat.f_fsidx.
vfs_getvfs(fsid)
Lookup a mount point with the file system identifier fsid.
vfs_export_lookup(mp, nep, argp)
Check client permission on the exportable file system specified
by the mount structure mp. The argument nam is the address of
the networked client. This function is used by file system type
specific functions to verify that the client can access the file
system.
vfs_setpublicfs(mp, nep, argp)
Set the publicly exported file system specified by the mount
structure mp.
vfs_mountedon(vp)
Check to see if a file system is mounted on a block device spec‐
ified by the vnode vp.
vfs_mountroot(void)
Mount the root file system.
vfs_unmountall(l)
Unmount all file systems.
vfs_busy(mp, flags, interlkp)
Mark the mount point specified by mp as busy. This function is
used to synchronize access and to delay unmounting. The inter‐
lock specified by argument interlkp is not released on failure.
vfs_unbusy(mp)
Free the busy file system specified by the mount structure mp.
vfs_mountalloc(vfsops, vp)
Allocate and initialise a mount structure, setting
mnt_vnodecovered to vp and mnt_op to vfsops. On success, mark
the mount structure as busy and return its address. Otherwise,
return NULL.
vfs_rootmountalloc(fstypename, devname, mpp)
Lookup a file system type specified by the name fstypename and
if found allocate and initialise a mount structure for it. The
allocated mount structure is returned in the address specified
by mpp. The device the root file system was mounted from is
specified by the argument devname and is recorded in the new
mount structure.
vfs_shutdown()
Sync and unmount all file systems before shutting down. Invoked
by cpu_reboot(9).
vfs_attach(vfs)
Establish file system vfs and initialise it.
vfs_detach(vfs)
Remove file system vfs from the kernel.
vfs_reinit(void)
Reinitialises all file systems within the kernel through file
system-specific vfs operation (see vfsops(9)).
vfs_getopsbyname(name)
Given a file system name specified by name, look up the vfs
operations for that file system (see vfsops(9)), or return NULL
if file system isn't present in the kernel.
vfs_suspend(mp, nowait)
Request a mounted file system to suspend all operations. All
new operations to the file system are stopped. After all opera‐
tions in progress have completed, the file system is synced to
disk and the function returns. If a file system suspension is
currently in progress and nowait is set EWOULDBLOCK is returned.
If the operation is successful, zero is returned, otherwise an
appropriate error code is returned.
vfs_resume(mp)
Request a mounted file system to resume operations.
CODE REFERENCES
The vfs interface functions are implemented within the files
sys/kern/vfs_subr.c and sys/kern/vfs_init.c.
SEE ALSOintro(9), namei(9), vfs(9), vfsops(9), vnode(9), vnodeops(9)BSD May 9, 2009 BSD
