Man pages matching name gfs_pio_flush in section 3:

gfs_pio_flush.3.en	debian 11 / libgfarm-dev
gfs_pio_flush.3.ja	debian 11 / libgfarm-dev
gfs_pio_flush.3.en	debian 12 / libgfarm-dev
gfs_pio_flush.3.ja	debian 12 / libgfarm-dev