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vfs(9) [netbsd man page]

VFS(9)							   BSD Kernel Developer's Manual						    VFS(9)

vfs -- kernel interface to file systems DESCRIPTION
The virtual file system, vfs, is the kernel interface to file systems. The interface specifies the calls for the kernel to access file sys- tems. It also specifies the core functionality that a file system must provide to the kernel. The focus of vfs activity is the vnode and is discussed in vnode(9). File system operations such as mounting and syncing are discussed in vfsops(9). SEE ALSO
intro(9), vfsops(9), vnode(9), vnodeops(9) BSD
September 22, 2001 BSD

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VFSSUBR(9)						   BSD Kernel Developer's Manual						VFSSUBR(9)

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). FUNCTIONS
vfs_getnewfsid(mp) Get a new unique file system id type for the file system specified 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 sys- tem. 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 specified 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 interlock 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 struc- ture 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 allo- cated 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 operations 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 ALSO
intro(9), namei(9), vfs(9), vfsops(9), vnode(9), vnodeops(9) BSD
May 9, 2009 BSD
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