-Ravi
On 15/04/20 2:05 pm, Ravishankar N
wrote:
On 10/04/20 2:06 am, Erik Jacobson wrote:
Once again thanks for sticking with us. Here is a reply from ScottRight, so afr_lookup_done() is resetting the event gen to zero. This looks like a race between lookup and inode refresh code paths. We made some changes to the event generation logic in AFR. Can you apply the attached patch and see if it fixes the split-brain issue? It should apply cleanly on glusterfs-7.4.
Titus. If you have something for us to try, we'd love it. The code had
your patch applied when gdb was run:
Here is the addr2line output for those addresses. Very interesting command, of
which I was not aware.
[root@leader3 ~]# addr2line -f -e/usr/lib64/glusterfs/7.2/xlator/cluster/
afr.so 0x6f735
afr_lookup_metadata_heal_check
afr-common.c:2803
[root@leader3 ~]# addr2line -f -e/usr/lib64/glusterfs/7.2/xlator/cluster/
afr.so 0x6f0b9
afr_lookup_done
afr-common.c:2455
[root@leader3 ~]# addr2line -f -e/usr/lib64/glusterfs/7.2/xlator/cluster/
afr.so 0x5c701
afr_inode_event_gen_reset
afr-common.c:755
Thanks,
Ravi
________ Community Meeting Calendar: Schedule - Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC Bridge: https://bluejeans.com/441850968 Gluster-users mailing list Gluster-users@xxxxxxxxxxx https://lists.gluster.org/mailman/listinfo/gluster-users
>From 11601e709a97ce7c40078866bf5d24b486f39454 Mon Sep 17 00:00:00 2001
From: Ravishankar N <ravishankar@xxxxxxxxxx>
Date: Wed, 15 Apr 2020 13:53:26 +0530
Subject: [PATCH] afr: event gen changes
The general idea of the changes is to prevent resetting event generation
to zero in the inode ctx, since event gen is something that should
follow 'causal order'.
Change #1:
For a read txn, in inode refresh cbk, if event_generation is
found zero, we are failing the read fop. This is not needed
because change in event gen is only a marker for the next inode refresh to
happen and should not be taken into account by the current read txn.
Change #2:
The event gen being zero above can happen if there is a racing lookup,
which resets even get (in afr_lookup_done) if there are non zero afr
xattrs. The resetting is done only to trigger an inode refresh and a
possible client side heal on the next lookup. That can be acheived by
setting the need_refresh flag in the inode ctx. So replaced all
occurences of resetting even gen to zero with a call to
afr_inode_need_refresh_set().
Change #3:
In both lookup and discover path, we are doing an inode refresh which is
not required since all 3 essentially do the same thing- update the inode
ctx with the good/bad copies from the brick replies. Inode refresh also
triggers background heals, but I think it is okay to do it when we call
refresh during the read and write txns and not in the lookup path.
Change-Id: Id0600dd34b144b4ae7a3bf3c397551adf7e402f1
Signed-off-by: Ravishankar N <ravishankar@xxxxxxxxxx>
---
...ismatch-resolution-with-fav-child-policy.t | 8 +-
xlators/cluster/afr/src/afr-common.c | 92 ++++---------------
xlators/cluster/afr/src/afr-dir-write.c | 6 +-
xlators/cluster/afr/src/afr.h | 5 +-
4 files changed, 29 insertions(+), 82 deletions(-)
diff --git a/tests/basic/afr/gfid-mismatch-resolution-with-fav-child-policy.t b/tests/basic/afr/gfid-mismatch-resolution-with-fav-child-policy.t
index f4aa351e4..12af0c854 100644
--- a/tests/basic/afr/gfid-mismatch-resolution-with-fav-child-policy.t
+++ b/tests/basic/afr/gfid-mismatch-resolution-with-fav-child-policy.t
@@ -168,8 +168,8 @@ TEST [ "$gfid_1" != "$gfid_2" ]
#We know that second brick has the bigger size file
BIGGER_FILE_MD5=$(md5sum $B0/${V0}1/f3 | cut -d\ -f1)
-TEST ls $M0/f3
-TEST cat $M0/f3
+TEST ls $M0 #Trigger entry heal via readdir inode refresh
+TEST cat $M0/f3 #Trigger data heal via readv inode refresh
EXPECT_WITHIN $HEAL_TIMEOUT "^0$" get_pending_heal_count $V0
#gfid split-brain should be resolved
@@ -215,8 +215,8 @@ TEST $CLI volume start $V0 force
EXPECT_WITHIN $PROCESS_UP_TIMEOUT "1" brick_up_status $V0 $H0 $B0/${V0}2
EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status $V0 2
-TEST ls $M0/f4
-TEST cat $M0/f4
+TEST ls $M0 #Trigger entry heal via readdir inode refresh
+TEST cat $M0/f4 #Trigger data heal via readv inode refresh
EXPECT_WITHIN $HEAL_TIMEOUT "^0$" get_pending_heal_count $V0
#gfid split-brain should be resolved
diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 61f21795e..319665a14 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -282,7 +282,7 @@ __afr_set_in_flight_sb_status(xlator_t *this, afr_local_t *local,
metadatamap |= (1 << index);
}
if (metadatamap_old != metadatamap) {
- event = 0;
+ __afr_inode_need_refresh_set(inode, this);
}
break;
@@ -295,7 +295,7 @@ __afr_set_in_flight_sb_status(xlator_t *this, afr_local_t *local,
datamap |= (1 << index);
}
if (datamap_old != datamap)
- event = 0;
+ __afr_inode_need_refresh_set(inode, this);
break;
default:
@@ -458,34 +458,6 @@ out:
return ret;
}
-int
-__afr_inode_event_gen_reset_small(inode_t *inode, xlator_t *this)
-{
- int ret = -1;
- uint16_t datamap = 0;
- uint16_t metadatamap = 0;
- uint32_t event = 0;
- uint64_t val = 0;
- afr_inode_ctx_t *ctx = NULL;
-
- ret = __afr_inode_ctx_get(this, inode, &ctx);
- if (ret)
- return ret;
-
- val = ctx->read_subvol;
-
- metadatamap = (val & 0x000000000000ffff) >> 0;
- datamap = (val & 0x00000000ffff0000) >> 16;
- event = 0;
-
- val = ((uint64_t)metadatamap) | (((uint64_t)datamap) << 16) |
- (((uint64_t)event) << 32);
-
- ctx->read_subvol = val;
-
- return ret;
-}
-
int
__afr_inode_read_subvol_get(inode_t *inode, xlator_t *this, unsigned char *data,
unsigned char *metadata, int *event_p)
@@ -556,22 +528,6 @@ out:
return ret;
}
-int
-__afr_inode_event_gen_reset(inode_t *inode, xlator_t *this)
-{
- afr_private_t *priv = NULL;
- int ret = -1;
-
- priv = this->private;
-
- if (priv->child_count <= 16)
- ret = __afr_inode_event_gen_reset_small(inode, this);
- else
- ret = -1;
-
- return ret;
-}
-
int
afr_inode_read_subvol_get(inode_t *inode, xlator_t *this, unsigned char *data,
unsigned char *metadata, int *event_p)
@@ -721,30 +677,22 @@ out:
return need_refresh;
}
-static int
-afr_inode_need_refresh_set(inode_t *inode, xlator_t *this)
+int
+__afr_inode_need_refresh_set(inode_t *inode, xlator_t *this)
{
int ret = -1;
afr_inode_ctx_t *ctx = NULL;
- GF_VALIDATE_OR_GOTO(this->name, inode, out);
-
- LOCK(&inode->lock);
- {
- ret = __afr_inode_ctx_get(this, inode, &ctx);
- if (ret)
- goto unlock;
-
+ ret = __afr_inode_ctx_get(this, inode, &ctx);
+ if (ret == 0) {
ctx->need_refresh = _gf_true;
}
-unlock:
- UNLOCK(&inode->lock);
-out:
+
return ret;
}
int
-afr_inode_event_gen_reset(inode_t *inode, xlator_t *this)
+afr_inode_need_refresh_set(inode_t *inode, xlator_t *this)
{
int ret = -1;
@@ -754,7 +702,7 @@ afr_inode_event_gen_reset(inode_t *inode, xlator_t *this)
"Resetting event gen for %s", uuid_utoa(inode->gfid));
LOCK(&inode->lock);
{
- ret = __afr_inode_event_gen_reset(inode, this);
+ ret = __afr_inode_need_refresh_set(inode, this);
}
UNLOCK(&inode->lock);
out:
@@ -1187,7 +1135,7 @@ afr_txn_refresh_done(call_frame_t *frame, xlator_t *this, int err)
ret = afr_inode_get_readable(frame, inode, this, local->readable,
&event_generation, local->transaction.type);
- if (ret == -EIO || (local->is_read_txn && !event_generation)) {
+ if (ret == -EIO) {
/* No readable subvolume even after refresh ==> splitbrain.*/
if (!priv->fav_child_policy) {
err = EIO;
@@ -2451,7 +2399,7 @@ afr_lookup_done(call_frame_t *frame, xlator_t *this)
if (read_subvol == -1)
goto cant_interpret;
if (ret) {
- afr_inode_event_gen_reset(local->inode, this);
+ afr_inode_need_refresh_set(local->inode, this);
dict_del_sizen(local->replies[read_subvol].xdata, GF_CONTENT_KEY);
}
} else {
@@ -3007,6 +2955,7 @@ afr_discover_unwind(call_frame_t *frame, xlator_t *this)
afr_private_t *priv = NULL;
afr_local_t *local = NULL;
int read_subvol = -1;
+ int ret = 0;
unsigned char *data_readable = NULL;
unsigned char *success_replies = NULL;
@@ -3028,7 +2977,10 @@ afr_discover_unwind(call_frame_t *frame, xlator_t *this)
if (!afr_has_quorum(success_replies, this, frame))
goto unwind;
- afr_replies_interpret(frame, this, local->inode, NULL);
+ ret = afr_replies_interpret(frame, this, local->inode, NULL);
+ if (ret) {
+ afr_inode_need_refresh_set(local->inode, this);
+ }
read_subvol = afr_read_subvol_decide(local->inode, this, NULL,
data_readable);
@@ -3284,11 +3236,7 @@ afr_discover(call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xattr_req)
afr_read_subvol_get(loc->inode, this, NULL, NULL, &event,
AFR_DATA_TRANSACTION, NULL);
- if (afr_is_inode_refresh_reqd(loc->inode, this, event,
- local->event_generation))
- afr_inode_refresh(frame, this, loc->inode, NULL, afr_discover_do);
- else
- afr_discover_do(frame, this, 0);
+ afr_discover_do(frame, this, 0);
return 0;
out:
@@ -3429,11 +3377,7 @@ afr_lookup(call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xattr_req)
afr_read_subvol_get(loc->parent, this, NULL, NULL, &event,
AFR_DATA_TRANSACTION, NULL);
- if (afr_is_inode_refresh_reqd(loc->inode, this, event,
- local->event_generation))
- afr_inode_refresh(frame, this, loc->parent, NULL, afr_lookup_do);
- else
- afr_lookup_do(frame, this, 0);
+ afr_lookup_do(frame, this, 0);
return 0;
out:
diff --git a/xlators/cluster/afr/src/afr-dir-write.c b/xlators/cluster/afr/src/afr-dir-write.c
index 82a72fddd..333085b14 100644
--- a/xlators/cluster/afr/src/afr-dir-write.c
+++ b/xlators/cluster/afr/src/afr-dir-write.c
@@ -119,11 +119,11 @@ __afr_dir_write_finalize(call_frame_t *frame, xlator_t *this)
continue;
if (local->replies[i].op_ret < 0) {
if (local->inode)
- afr_inode_event_gen_reset(local->inode, this);
+ afr_inode_need_refresh_set(local->inode, this);
if (local->parent)
- afr_inode_event_gen_reset(local->parent, this);
+ afr_inode_need_refresh_set(local->parent, this);
if (local->parent2)
- afr_inode_event_gen_reset(local->parent2, this);
+ afr_inode_need_refresh_set(local->parent2, this);
continue;
}
diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index a3f2942b3..ed6d777c1 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -958,7 +958,10 @@ afr_inode_read_subvol_set(inode_t *inode, xlator_t *this,
int event_generation);
int
-afr_inode_event_gen_reset(inode_t *inode, xlator_t *this);
+__afr_inode_need_refresh_set(inode_t *inode, xlator_t *this);
+
+int
+afr_inode_need_refresh_set(inode_t *inode, xlator_t *this);
int
afr_read_subvol_select_by_policy(inode_t *inode, xlator_t *this,
--
2.25.2
________ Community Meeting Calendar: Schedule - Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC Bridge: https://bluejeans.com/441850968 Gluster-users mailing list Gluster-users@xxxxxxxxxxx https://lists.gluster.org/mailman/listinfo/gluster-users
