wait_on_bit_io
wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&mblk->state, DMZ_META_READING,
wait_on_bit_io(&mblk->state, DMZ_META_WRITING,
wait_on_bit_io(&zrc->flags, DMZ_RECLAIM_KCOPY,
wait_on_bit_io(&inode->root->fs_info->flags, BTRFS_FS_NEED_ZONE_FINISH,
wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_READING,
wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_READING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
wait_on_bit_io(&inode->root->fs_info->flags,
wait_on_bit_io(&bh->b_state, BH_Lock, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&ip->i_flags, GIF_GLOP_PENDING, TASK_UNINTERRUPTIBLE);
wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE);
return wait_on_bit_io(&req->wb_flags, PG_BUSY,