drbd: Do not full sync if a P_SYNC_UUID packet gets lost
See also commit from 2009-08-15
"drbd_uuid_compare(): Do not full sync in case a P_SYNC_UUID packet gets lost."
We saw cases where the History UUIDs where not as expected. So the
detection of the special case did not trigger. With the sync UUID
no longer being a random number, but deducible from the previous
bitmap UUID, the detection of this special case becomes more
reliable.
The SyncUUID now is the previous bitmap UUID + 0x1000000000000.
Rule 5a:
Cs = H1p & H1p + Offset = Bp
Connection was lost before SyncUUID Packet came through.
Corrent (peer) UUIDs:
Bp = H1p
H1p = H2p
H2p = 0
Become Sync target.
Rule 7a:
Cp = H1s & H1s + Offset = Bs
Connection was lost before SyncUUID Packet came through.
Correct (own) UUIDs:
Bs = H1s
H1s = H2s
H2s = 0
Become Sync source.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 84b4575..3c8eecd 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -97,6 +97,7 @@
#define ID_SYNCER (-1ULL)
#define ID_VACANT 0
#define is_syncer_block_id(id) ((id) == ID_SYNCER)
+#define UUID_NEW_BM_OFFSET ((u64)0x0001000000000000ULL)
struct drbd_conf;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index da98bff..b3b6d31 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2022,7 +2022,7 @@
D_ASSERT(mdev->state.disk == D_UP_TO_DATE);
- get_random_bytes(&uuid, sizeof(u64));
+ uuid = mdev->ldev->md.uuid[UI_BITMAP] + UUID_NEW_BM_OFFSET;
drbd_uuid_set(mdev, UI_BITMAP, uuid);
drbd_md_sync(mdev);
p.uuid = cpu_to_be64(uuid);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index fd0957f..7991183 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2293,6 +2293,8 @@
-2 C_SYNC_TARGET set BitMap
-100 after split brain, disconnect
-1000 unrelated data
+-1091 requires proto 91
+-1096 requires proto 96
*/
static int drbd_uuid_compare(struct drbd_conf *mdev, int *rule_nr) __must_hold(local)
{
@@ -2322,7 +2324,7 @@
if (mdev->p_uuid[UI_BITMAP] == (u64)0 && mdev->ldev->md.uuid[UI_BITMAP] != (u64)0) {
if (mdev->agreed_pro_version < 91)
- return -1001;
+ return -1091;
if ((mdev->ldev->md.uuid[UI_BITMAP] & ~((u64)1)) == (mdev->p_uuid[UI_HISTORY_START] & ~((u64)1)) &&
(mdev->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) == (mdev->p_uuid[UI_HISTORY_START + 1] & ~((u64)1))) {
@@ -2343,7 +2345,7 @@
if (mdev->ldev->md.uuid[UI_BITMAP] == (u64)0 && mdev->p_uuid[UI_BITMAP] != (u64)0) {
if (mdev->agreed_pro_version < 91)
- return -1001;
+ return -1091;
if ((mdev->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) == (mdev->p_uuid[UI_BITMAP] & ~((u64)1)) &&
(mdev->ldev->md.uuid[UI_HISTORY_START + 1] & ~((u64)1)) == (mdev->p_uuid[UI_HISTORY_START] & ~((u64)1))) {
@@ -2388,17 +2390,22 @@
*rule_nr = 51;
peer = mdev->p_uuid[UI_HISTORY_START] & ~((u64)1);
if (self == peer) {
- self = mdev->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1);
- peer = mdev->p_uuid[UI_HISTORY_START + 1] & ~((u64)1);
- if (self == peer) {
+ if (mdev->agreed_pro_version < 96 ?
+ (mdev->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) ==
+ (mdev->p_uuid[UI_HISTORY_START + 1] & ~((u64)1)) :
+ peer + UUID_NEW_BM_OFFSET == (mdev->p_uuid[UI_BITMAP] & ~((u64)1))) {
/* The last P_SYNC_UUID did not get though. Undo the last start of
resync as sync source modifications of the peer's UUIDs. */
if (mdev->agreed_pro_version < 91)
- return -1001;
+ return -1091;
mdev->p_uuid[UI_BITMAP] = mdev->p_uuid[UI_HISTORY_START];
mdev->p_uuid[UI_HISTORY_START] = mdev->p_uuid[UI_HISTORY_START + 1];
+
+ dev_info(DEV, "Did not got last syncUUID packet, corrected:\n");
+ drbd_uuid_dump(mdev, "peer", mdev->p_uuid, mdev->p_uuid[UI_SIZE], mdev->p_uuid[UI_FLAGS]);
+
return -1;
}
}
@@ -2420,20 +2427,20 @@
*rule_nr = 71;
self = mdev->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1);
if (self == peer) {
- self = mdev->ldev->md.uuid[UI_HISTORY_START + 1] & ~((u64)1);
- peer = mdev->p_uuid[UI_HISTORY_START] & ~((u64)1);
- if (self == peer) {
+ if (mdev->agreed_pro_version < 96 ?
+ (mdev->ldev->md.uuid[UI_HISTORY_START + 1] & ~((u64)1)) ==
+ (mdev->p_uuid[UI_HISTORY_START] & ~((u64)1)) :
+ self + UUID_NEW_BM_OFFSET == (mdev->ldev->md.uuid[UI_BITMAP] & ~((u64)1))) {
/* The last P_SYNC_UUID did not get though. Undo the last start of
resync as sync source modifications of our UUIDs. */
if (mdev->agreed_pro_version < 91)
- return -1001;
+ return -1091;
_drbd_uuid_set(mdev, UI_BITMAP, mdev->ldev->md.uuid[UI_HISTORY_START]);
_drbd_uuid_set(mdev, UI_HISTORY_START, mdev->ldev->md.uuid[UI_HISTORY_START + 1]);
- dev_info(DEV, "Undid last start of resync:\n");
-
+ dev_info(DEV, "Last syncUUID did not get through, corrected:\n");
drbd_uuid_dump(mdev, "self", mdev->ldev->md.uuid,
mdev->state.disk >= D_NEGOTIATING ? drbd_bm_total_weight(mdev) : 0, 0);
@@ -2496,8 +2503,8 @@
dev_alert(DEV, "Unrelated data, aborting!\n");
return C_MASK;
}
- if (hg == -1001) {
- dev_alert(DEV, "To resolve this both sides have to support at least protocol 91\n");
+ if (hg < -1000) {
+ dev_alert(DEV, "To resolve this both sides have to support at least protocol %d\n", -hg - 1000);
return C_MASK;
}
