f2fs: add f2fs_balance_fs for direct IO
f2fs: add f2fs_balance_fs for direct IO

Otherwise, if a large amount of direct IO writes were done, the
segment allocation may be failed because no enough segments are gced.

Changes:

v2: add f2fs_balance_fs into __get_data_block instead of f2fs_direct_IO.

Signed-off-by: Huang, Ying <b1ed892af366400004b51f70e40351e33707b6c4@intel.com>
Signed-off-by: Jaegeuk Kim <71255387a32c360dfbe6dfb7aaeb123bf1dc8cb6@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs