funmount(8)

NAME

funmount - forcibly unmount a file system

SYNOPSIS

funmount path

DESCRIPTION

funmount forcibly attempts to unmount the file system

mounted on path. It is roughly equivalent to running umount -f

path. However, on most operating systems the umount command does

a great deal more than simply execute the unmount system

call--for instance it may attempt to read the attributes of the

file system being unmounted and/or contact a remote NFS server to

notify it of the unmount operation. These extra actions make

umount hang when a remote NFS server is unavailable or a loopback

server has crashed, which in turn causes the client to become ev

er more wedged. funmount can avoid such situations when you are

trying to salvage a machine with bad NFS mounts without rebooting

it.

CAVEATS

SFS will get very confused if you ever unmount file sys

tems from beneath it. SFS's nfsmounter program tries to clean up

the mess if the client software ever crashes. Running funmount

will generally only make things worse by confusing nfsmounter.

SEE ALSO

dirsearch(1), newaid(1), rex(1), sfsagent(1), sfskey(1),

ssu(1), sfs_config(5), sfs_hosts(5), sfs_srp_params(5),

sfs_users(5), sfsauthd_config(5), sfscd_config(5),

sfsrosd_config(5), sfsrwsd_config(5), sfssd_config(5),

sfs_environ(7), nfsmounter(8), sfsauthd(8), sfscd(8), sfsrosd(8),

sfsrwcd(8), sfsrwsd(8), sfssd(8), vidb(8)

The full documentation for SFS is maintained as a Texinfo

manual. If the info and SFS programs are properly installed at

your site, the command info SFS should give you access to the

complete manual.

For updates, documentation, and software distribution,

please see the SFS website at http://www.fs.net/.

BUGS

If /a is a mount point, and /a/b is another mount point,

unmounting /a before /a/b will cause the latter file system to

become ``lost.'' Once a file system is lost, there is no way to

unmount it without rebooting. Worse yet, on some operating sys

tems, commands such as df may hang because of a lost file system.

Many operating systems will not let you unmount a file

system (even forcibly) if a process is using the file system's

root directory (for instance as a current working directory).

Under such circumstances, funmount may fail. To unmount the file

system you must find and kill whatever process is using the di

rectory. Utilities such as fstat and lsof may be helpful for

identifying processes with a particular file system open.

AUTHOR

sfsdev@redlab.lcs.mit.edu

SFS 0.8pre 2006-07-20

FUNMOUNT(8)