commit 1c8924eb upstream.

ext4 needs to convert allocated (metadata) blocks back into blocks
reserved for delayed allocation. Add functions into quota code for
supporting such operation.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Josh Hunt <johunt@akamai.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>