For example, if we have 5 mds in the mdsmap and the states are:
m_info[5] --> [-1, 1, -1, 1, 1]
If we get a random number 1, then we should get the mds index 3 as
expected, but actually we will get index 2, which the state is -1.
The issue is that the for loop increment will advance past any "up"
MDS that was found during the while loop search.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
{
int n = 0;
- int i;
+ int i, j;
/* special case for one mds */
if (1 == m->m_num_mds && m->m_info[0].state > 0)
/* pick */
n = prandom_u32() % n;
- for (i = 0; n > 0; i++, n--)
- while (m->m_info[i].state <= 0)
- i++;
+ for (j = 0, i = 0; i < m->m_num_mds; i++) {
+ if (m->m_info[i].state > 0)
+ j++;
+ if (j > n)
+ break;
+ }
return i;
}