global in_process
global writers
global last
global seeks

probe kernel.function("__log_wait_for_space@fs/jbd/checkpoint.c") {
    printf("%d ext3 waiting for space\n", pid())
    p = pid()
    writers[p] = 0
    in_process[p] = 1
    last[p] = 0
    seeks[p] = 0
}

probe kernel.function("__log_wait_for_space@fs/jbd/checkpoint.c").return {
    p = pid()
    in_process[p] = 0
    printf("%d ext3 done waiting for space total wrote %d blocks seeks %d\n", p,
	  writers[p], seeks[p])
}

probe kernel.function("submit_bh") {
    p = pid()
    in_proc = in_process[p]
    if (in_proc != 0) {
	writers[p] += 1
	block = $bh->b_blocknr
	last_block = last[p]
	diff = 0
	if (last_block != 0) {
	    if (last_block < block && block - last_block > 16) {
		diff = block - last_block
	    }
	    if (last_block > block && last_block - block > 16) {
		diff = last_block - block
	    }
	}
	    
	last[p] = block
	if (diff != 0) {
	    printf("seek log write pid %d last %d this %d diff %d\n",
		       p, last_block, block, diff);
	    seeks[p] += 1
	}
    }
}