Bash script to add psuedo-remount functionality to NFS mounts in Linux

nfs-remount.sh

#!/bin/bash
#
# Remount a filesystem with new options by unmounting it first (with umount)
# and mounting it again.
#
# Used for filesystems that do not support the -o remount option (eg. NFS).
#
# Compatible with Linux/bash only.
#
# 2012-07-17
# [email protected]
#

# Get -o mount options
while getopts ":o:" opt; do
    case $opt in
        o)
            mountoptions="$mountoptions $OPTARG"
            ;;
    esac
done

shift $(($OPTIND-1))
mountpoint="$@"

# Show usage
if [ $# -lt 1 -o -z "$mountpoint" ]; then
    echo "Unmounts and re-mounts a mount point with new options. Useful when the" >&2
    echo "filesystem doesn't support remounting (such as NFS)." >&2
    echo >&2
    echo "Usage: $0 [-o options] <mount point>" >&2
    echo >&2
    echo "NOTE: Existing mount options are not preserved." >&2
    exit 99
fi

# Iterate over current mount points to find the one that the user has specified
while read mount; do

    # Parse mount arguments
    set -- $mount
    src=$1
    target=$2

    if [ "$target" == "$mountpoint" ]; then

        # Unmount
        umount "$target" || exit

        # Mount again with the new options
        mount -o $mountoptions "$src" "$target" || {

            # A feeble attempt to re-mount successfully if the mount failed
            # (in case the user specified invalid options)
            mount "$src" "$target" &>/dev/null || echo "Unable to restore mount" >&2
            exit 1
        }

        # Success!
        exit 0
    fi

done </proc/mounts

echo "Could not find $mountpoint in /proc/mounts." >&2