Protect the Gluster FS mount directory

When the applications use the mount path to store the files, it may happen that the mount process may have crashed and the application continues to create the files in the root partition itself. Check the example below to understand the issue

# Create the mount directory
mkdir /mnt/vol1

# Mount the Glusterfs Volume
mount -t glusterfs server1.gluster:/vol1 /mnt/vol1

# Application creating the file
echo "Hello World!" > /mnt/vol1/file1

# Now simulate the mount crash by killing
# the `glusterfs` process or by
# unmounting the volume.
umount /mnt/vol1

# Application creating or updating the file
echo "Hello Again!" > /mnt/vol1/file2

In the above example, the file (file2) was not created on the Gluster FS volume. This is a serious problem. To protect the mount directory, make it immutable before mounting it.

# Create the mount directory
mkdir /mnt/vol1

# Make the directory immutable
chattr +i /mnt/vol1

# Mount the Glusterfs Volume
mount -t glusterfs server1.gluster:/vol1 /mnt/vol1

# Application creating the file
echo "Hello World!" > /mnt/vol1/file1

# Now simulate the mount crash by killing
# the `glusterfs` process or by
# unmounting the volume.
umount /mnt/vol1

# Application creating or updating the file
# This command will fail now.
echo "Hello Again!" > /mnt/vol1/file2