I have ArchLiinux Linux comp001 3.18.7-1-ARCH #1 PREEMPT Wed Feb 11 11:38:34 MST 2015 armv6l GNU/Linux for Arm installed on rPi and here is my /etc/fstab file:## /etc/fstab: static file system information## <file system> <dir>   <type>  <options>   <dump>  <pass>/dev/mmcblk0p1  /boot       vfat    defaults            0       0/dev/mmcblk0p3  /mnt/data   vfat    noexec,rw,noatime,user,umask=022        0       2Partition /dev/mmcblkop3 (microsd card fat32 partition) is mounted on mnt/data with rw options, but if I list /mnt directory, I get:total 20 4 drwxr-xr-x  3 root root  4096 Sep 18 13:27 . 4 drwxr-xr-x 18 root root  4096 Jan  9 11:08 ..12 drwxr-xr-x  3 root root 12288 Jan  1  1970 dataWhy there is not write permission bit set on data?
/etc/fstab/ rw option is being ignored for mircosd card partition in ArchLinux
arch linux;filesystems;fstab;fat
You are confusing the rw option with the umask.The rw option merely dictates that the partition is not mounted read-only.The umask option dictates what permission that not set on files and directories.  Your current umask of 022 sets the permission bits to 755 which translates to rwxr-xr-x.  Change the umask to 000, which should give you 777 or rwxrwxrwx permissions.More info on umask is available on Wikipedia