• Darrick J. Wong's avatar
    ext4: check s_chksum_driver when looking for bg csum presence · 813d32f9
    Darrick J. Wong authored
    Convert the ext4_has_group_desc_csum predicate to look for a checksum
    driver instead of the metadata_csum flag and change the bg checksum
    calculation function to look for GDT_CSUM before taking the crc16
    Without this patch, if we mount with ^uninit_bg,^metadata_csum and
    later metadata_csum gets turned on by accident, the block group
    checksum functions will incorrectly assume that checksumming is
    enabled (metadata_csum) but that crc16 should be used
    (!s_chksum_driver).  This is totally wrong, so fix the predicate
    and the checksum formula selection.
    (Granted, if the metadata_csum feature bit gets enabled on a live FS
    then something underhanded is going on, but we could at least avoid
    writing garbage into the on-disk fields.)
    Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    Reviewed-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
    Cc: stable@vger.kernel.org
ext4.h 101 KB