Provided by: ext2resize_1.1.19-3_i386 bug


       ext2online - online (mounted) ext2 filesystem resizer


       ext2online   [-C   fd]   [-d]   [-q]   [-v]   [-V]  {device|mountpoint}


       The ext2online tool resizes ext2 file systems while  they  are  mounted
       and in use by the system.  It is OK to resize the filesystem even while
       programs have open files and are writing into the  filesystem.   It  is
       only  possible  to enlarge a mounted filesystem.  It is possible to use
       ext2resize(8) to shrink and enlarge an  unmounted  filesystem.   To  be
       able to use ext2online, you need to have the Online ext2 resize support
       (CONFIG_EXT2_RESIZE) feature enabled in the kernel (after applying  the
       appropriate patch for the 2.x series of kernels).

       The  filesystem  specified  by  device (partition, loop device, logical
       volume, ...) or mountpoint must currently be mounted, and  it  will  be
       enlarged  to  fill  the  device,  by  default.   If  the  optional size
       parameter is specified, then this size will be used  instead.   If  the
       size  parameter does not have an optional modifier, it will be taken to
       be in ext2 filesystem blocks (which  can  be  1k,  2k,  or  4k  -   use
       dumpe2fs(8) to find out more information about the current filesystem).
       The modifiers b, K, M, G, or T mean the  size  parameter  is  given  in
       512-byte blocks, kilo-, mega-, giga-, or terabytes respectively.

       The  ext2online program does not change the size of the actual device -
       only the filesystem.  If you wish to enlarge  a  filesystem,  you  must
       make  sure  you  expand  the underlying device first.  This can be done
       online for Logical Volumes by using lvextend(8) from the  LVM  package,
       or  for  ease-of-use  you  can  use  e2fsadm(8)  which  combines the LV
       extension and ext2 filesystem resizing into one step.  Alternately, you
       may be able to use facilities in md or RAID facilities in the hardware,
       if you are not using a partition table.  It is not possible to do  this
       by using the fdisk(8) family of tools to extend a partition while it is
       mounted (at least the author has  not  been  able  to  successfully  do

       Because  of  the  original  design  of the ext2 filesystem did not have
       online resizing in mind, there are certain limitations to the amount of
       resizing  that  can  be  done  while  the filesystem is mounted, if you
       haven’t done any preparation for the resize.  The  default  block  size
       for  ext2  was  1k  blocks  until  v1.15  of e2fsprogs (1999), where it
       changed to 4k blocks for filesystems larger than 512MB.

       With no filesystem preparation, it is always possible to resize to  the
       next  256MB  boundary for 1k filesystems, the next 2GB boundary for for
       2k filesystems, and the next 16GB  boundary  for  4k  filesystems.   By
       using  the  ext2prepare(8)  program  on  an unmounted filesystem, it is
       possible for  ext2online  to  increase  the  size  of  a  mounted  ext2
       filesystem to almost any size.


       -C fd, --completion=fd
              Output completion information to file descriptor fd.

       -d, --debug
              Turn on debugging messages.

       -q, --quiet
              Do not print anything but error messages.

       -v, --verbose
              Turn on normal verbose status messages.

       -V, --version
              Print the version number and exit.


       0    Resizing successful

       1    Error in command line (options or specified device)

       2    Error in specified size

       3    Error in pre-resizing (user space) operation

       4    Error during the in-kernel resizing operation

       5    Error in post-resizing operation (update of metadata backups)


       The  following  example  shows  how  to  test  ext2online  with a spare
       partition.  First a filesystem  of  32MB  is  created  on  the  device,
       mounted,  and the size is verified.  The filesystem is then extended to
       fill the device (the default action when no size is given), and the new
       size is verified.

            dd if=/dev/zero of=/tmp/file bs=1k count=64k
            mke2fs -F -f 32768 /tmp/file
            mkdir /tmp/test
            mount -o loop,debug,check=strict /tmp/file /tmp/test
            df /mnt/test
            ext2online -d -v /tmp/file
            df /tmp/test

       By using the debug and check=strict options to mount, as well as the -d
       and -v flags to ext2online, we will see the user-space status messages,
       and the kernel messages will be logged by syslog.


       Note that resizing a mounted filesystem is inherently dangerous and may
       corrupt filesystems, although no errors resulting  in  data  loss  have
       ever  been  reported  to  the author.  In theory online resizing should
       work fine with arbitrarily large filesystems, but it has not  yet  been
       tested  by  the  author  on  a  filesystem  larger than 11GB.  Use with
       caution.  Backups are always a good idea, because your disk may fail at
       any time, you delete files by accident, or your computer is struck by a


       The   ext2online   program    was    written    by    Andreas    Dilger
       <>  using  the  ext2  resizing  tools developed by
       Lennert Buytenhek <>.  The ext2online kernel patches are
       available    as    part    of    the    GNU   ext2resize   package   at


       There is a limit imposed on a single filesystem resize due to the  fact
       that  ext2online  does  not  use  triple-indirect blocks for the resize
       inode.  This should not affect most users of ext2online, as  the  limit
       is  about  60GB  larger  than  the current filesystem size for 1k block
       filesystems.   The  ext2resize  programs  do  not  work  on  big-endian
       machines (Alpha, SPARC, PPC, etc).


       ext2online  is (C) Copyright 1999, 2000, 2001 by Andreas Dilger and may
       be distributed under the terms of the GNU General Public License.


       dumpe2fs(8)   ext2prepare(8)   ext2resize(8)    e2fsadm(8)    e2fsck(8)