gfs2_iomap_alloc
ret = gfs2_iomap_alloc(inode, pos, length, &iomap);
ret = gfs2_iomap_alloc(inode, lblock << blkbits, *extlen << blkbits,
int gfs2_iomap_alloc(struct inode *inode, loff_t pos, loff_t length,
error = gfs2_iomap_alloc(inode, offset, end - offset, &iomap);
if (gfs2_iomap_alloc(folio->mapping->host, pos, length, &iomap))