tree 09233f55cd3aa55cf779f684cd1968cc36a08437
parent 50db71abc529c48b21f4c3034d3cff27cfb25795
author Theodore Ts'o <tytso@mit.edu> 1419656301 -0500
committer Theodore Ts'o <tytso@mit.edu> 1419656301 -0500

ext4: prevent online resize with backup superblock

Prevent BUG or corrupted file systems after the following:

mkfs.ext4 /dev/vdc 100M
mount -t ext4 -o sb=40961 /dev/vdc /vdc
resize2fs /dev/vdc

We previously prevented online resizing using the old resize ioctl.
Move the code to ext4_resize_begin(), so the check applies for all of
the resize ioctl's.

Reported-by: Maxim Malkov <malkov@ispras.ru>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>