Manual Pages for UNIX Operating System command usage for man umount2

System Calls                                            umount(2)



NAME
     umount, umount2 - unmount a file system

SYNOPSIS
     #include 

     int umount(const char *file);


     int umount2(const char *file, int mflag);


DESCRIPTION
     The umount()  function requests that  a  previously  mounted
     file system contained on a block special device or directory
     be unmounted.  The file argument is a pointer to  the  abso-
     lute  pathname  of  the  file  system to be unmounted. After
     unmounting the file system, the  directory  upon  which  the
     file  system was mounted reverts to its ordinary interpreta-
     tion.


     The umount2()  function is identical to umount(),  with  the
     additional  capability  of  unmounting  file systems even if
     there are open files active. The mflag argument must contain
     one of the following values:

     0           Perform a normal unmount that is  equivalent  to
                 umount().  The umount2() function  returns EBUSY
                 if there are open files active within  the  file
                 system to be unmounted.


     MS_FORCE    Unmount the file system, even if there are  open
                 files  active.  A  forced  unmount can result in
                 loss of data, so it should be used only  when  a
                 regular  unmount  is unsuccessful. The umount2()
                 function  returns ENOTSUP if the specified  file
                 systems  does  not  support  MS_FORCE. Only file
                 systems of type nfs, ufs, pcfs, and zfs  support
                 MS_FORCE.


RETURN VALUES
     Upon successful completion, 0 is returned. Otherwise, -1  is
     returned and errno is set to indicate the error.

ERRORS
     The umount() and umount2() functions will fail if:

     EACCES          The permission bits of the  mount  point  do
                     not   permit  read/write  access  or  search



SunOS 5.11           Last change: 4 Aug 2008                    1






System Calls                                            umount(2)



                     permission is denied on a component  of  the
                     path prefix.

                     The calling process is not the owner of  the
                     mountpoint.

                     The mountpoint is not a regular  file  or  a
                     directory  and  the caller does not have all
                     privileges available in a its zone.

                     The special device device  does  not  permit
                     read  access in the case of read-only mounts
                     or  read-write  access  in   the   case   of
                     read/write mounts.


     EBUSY           A file on file is busy.


     EFAULT          The file pointed to by  file  points  to  an
                     illegal address.


     EINVAL          The file pointed to by file is not mounted.


     ELOOP           Too many symbolic links were encountered  in
                     translating the path pointed to by file.


     ENAMETOOLONG    The length  of  the  file  argument  exceeds
                     PATH_MAX, or the length of a  file component
                     exceeds NAME_MAX while _POSIX_NO_TRUNC is in
                     effect.


     ENOENT          The file pointed to by file does  not  exist
                     or is not an absolute path.


     ENOLINK         The file pointed to by file is on  a  remote
                     machine  and  the link to that machine is no
                     longer active.


     ENOTBLK         The file pointed to by file is not  a  block
                     special device.


     EPERM           The  {PRIV_SYS_MOUNT}   privilege   is   not
                     asserted in the effective set of the calling
                     process.



SunOS 5.11           Last change: 4 Aug 2008                    2






System Calls                                            umount(2)



     EREMOTE         The file pointed to by file is remote.



     The umount2() function will fail if:

     ENOTSUP    The file pointed to by file does not support this
                operation.


USAGE
     The umount() and umount2() functions can be invoked only  by
     a  process  that has the {PRIV_SYS_MOUNT} privilege asserted
     in its effective set.


     Because it provides  greater  functionality,  the  umount2()
     function is preferred.

SEE ALSO
     mount(2), privileges(5)


































SunOS 5.11           Last change: 4 Aug 2008                    3