vfssubr(9) - NetBSD Manual Pages

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VFSSUBR(9)             NetBSD 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, vfs_vnode_iterator_init,
     vfs_vnode_iterator_destroy, vfs_vnode_iterator_next -- high-level inter-
     face 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);

     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);

     void
     vfs_vnode_iterator_init(struct mount *mp, struct vnode_iterator **vip);

     void
     vfs_vnode_iterator_destroy(struct vnode_iterator *vi);

     struct vnode *
     vfs_vnode_iterator_next(struct vnode_iterator *vi,
         bool (*selector)(void *context, struct vnode *vpp), void *context);


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 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)
              Mark the mount point specified by mp as busy and get a reference
              to it.  This function is used to synchronize access and to delay
              unmounting.  The caller must hold a pre-existing reference to
              the mount.

     vfs_unbusy(mp)
              Undo a vfs_busy() on the mount point specified by mp.

     vfs_mountalloc(vfsops, vp)
              Allocate and initialise a mount structure, setting
              mnt_vnodecovered to vp and mnt_op to vfsops.  On success return
              the address of the mount structure.  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 marked as busy and 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.

     vfs_vnode_iterator_init(mp, vip)
              Allocate and initialize an iterator vip over all vnodes attached
              to mount point mp.

     vfs_vnode_iterator_destroy(vi)
              Free all resources associated with an iterator vi.

     vfs_vnode_iterator_next(vi, selector, context)
              Return the next vnode from iterator vi.  If the operation is
              successful the vnode has a reference added to it and it is
              returned.  If the iterator is exhausted the function returns
              NULL.  If an optional selector function is provided, then this
              function is called with the context provided and the candidate
              vnode to be returned.  If the selector returns false, then the
              vnode is skipped; if it returns true, the vnode is referenced
              and then returned.


CODE REFERENCES

     The vfs interface functions are implemented within the files
     sys/kern/vfs_mount.c, 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)

NetBSD 9.3                      April 17, 2017                      NetBSD 9.3