Monitor a list of currently mounted filesystems

You know that /proc/mounts and /proc/self/mountinfo contain list of currently mounted filesystems. These files is possible to monitor by poll(2) or select(2) functions. The util findmnt(8) exports this functionality to command line.

Examples:

session A (monitor):                                          
   findmnt --poll
session B (event):
   mount /home/fs-images/ext2.img /mnt/test
                                                 
session A (findmnt output after event):       
   ACTION     TARGET    SOURCE     FSTYPE OPTIONS
   mount      /mnt/test /dev/loop0 ext2   rw,relatime,user_xattr,acl,barrier=1

The another examples; wait until /mnt/test is unmounted:

   findmnt --poll=umount --first-only /mnt/test

Inform me about all ext2, ext3, and ext4 remounts to read-only mode:

   findmnt --poll=remount --types ext2,ext3,ext4 --options ro

You can also define output columns, for example if you want to know more about "mount --move" operations:

   # findmnt --poll=move -o OLD-TARGET,TARGET,SOURCE
   OLD-TARGET TARGET   SOURCE                      
   /mnt/test  /mnt/foo /dev/loop0                  

the event in this example was generated by "mount --move /mnt/test /mnt/foo" command.

And for example if you want info about old and new options after remount:

   # findmnt --poll=remount -o TARGET,OLD-OPTIONS,OPTIONS
   TARGET   OLD-OPTIONS                          OPTIONS
   /mnt/foo ro,relatime,user_xattr,acl,barrier=1 rw,user_xattr,acl,barrier=1

this event was generated by "mount -o remount /mnt/foo -o rw,strictatime" command.

All this is available in util-linux 2.20 (e.g. Fedora 16).