mark
This module matches the netfilter mark field associated with a packet (which can be set using the MARK target below).
[!] --mark value[/mask]
Matches packets with the given unsigned mark value (if a mask is specified, this is logically ANDed with the mask
before the comparison).
uid=value and gid=value
Set the owner and group of all files. (Default: the UID and GID of the current process.)
umask=value
Set the umask (the bitmask of the permissions that are not present). The default is the umask of the current process. The value is given in octal.
dmask=value
Set the umask applied to directories only. The default is the umask of the current process. The value is given in octal.
fmask=value
Set the umask applied to regular files only. The default is the umask of the current process. The value is given in octal.
dd if=/dev/zero bs=1M count=50 of=bigfile
mkfs.vfat bigfile
sudo mount -o loop bigfile /mnt/tmp
sudo mkdir /mnt/tmp/dir
sudo umount /mnt/tmp
sudo mount -o loop,dmask=000 bigfile /mnt/tmp
ls -l /mnt/tmp