getblkx
error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp);
error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp);
error = getblkx(vp, lblkno, lblkno, size, 0, 0, gbflags, &bp);
int getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size,
error = getblkx(devvp, dbn, dbn, fs->fs_cgsize, 0, 0, 0, &bp);
error = getblkx(devvp, dbn, dbn, fs->fs_cgsize, 0, 0, 0, &bp);
error = getblkx(vp, lblkno, dblkno, size, 0, 0, flags, bpp);