Currently, osd_weight and osd_state fields are updated in the encoding
order. This is wrong, because an incremental map may look like e.g.
new_up_client: { osd=6, addr=... } # set osd_state and addr
new_state: { osd=6, xorstate=EXISTS } # clear osd_state
Suppose osd6's current osd_state is EXISTS (i.e. osd6 is down). After
applying new_up_client, osd_state is changed to EXISTS | UP. Carrying
on with the new_state update, we flip EXISTS and leave osd6 in a weird
"!EXISTS but UP" state. A non-existent OSD is considered down by the
mapping code
2087 for (i = 0; i < pg->pg_temp.len; i++) {
2088 if (ceph_osd_is_down(osdmap, pg->pg_temp.osds[i])) {
2089 if (ceph_can_shift_osds(pi))
2090 continue;
2091
2092 temp->osds[temp->size++] = CRUSH_ITEM_NONE;
and so requests get directed to the second OSD in the set instead of
the first, resulting in OSD-side errors like:
[WRN] : client.4239 192.168.122.21:0/2444980242 misdirected client.4239.1:2827 pg 2.5df899f2 to osd.4 not [1,4,6] in e680/680
and hung rbds on the client:
[ 493.566367] rbd: rbd0: write 400000 at 11cc00000 (0)
[ 493.566805] rbd: rbd0: result -6 xferred 400000
[ 493.567011] blk_update_request: I/O error, dev rbd0, sector 9330688
The fix is to decouple application from the decoding and:
- apply new_weight first
- apply new_state before new_up_client
- twiddle osd_state flags if marking in
- clear out some of the state if osd is destroyed
Fixes: http://tracker.ceph.com/issues/14901
Cc: stable@vger.kernel.org # 3.15+: 6dd74e44dc1d: libceph: set 'exists' flag for newly up osd
Cc: stable@vger.kernel.org # 3.15+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
930c532869