From b9b479de2a7fd1c5eefa7aa1142e0a39e0c96ca9 Mon Sep 17 00:00:00 2001
From: Xavi Hernandez <xhernandez@redhat.com>
Date: Sun, 1 Mar 2020 19:49:04 +0100
Subject: [PATCH 419/449] cluster/afr: fix race when bricks come up
The was a problem when self-heal was sending lookups at the same time
that one of the bricks was coming up. In this case there was a chance
that the number of 'up' bricks changes in the middle of sending the
requests to subvolumes which caused a discrepancy in the expected
number of replies and the actual number of sent requests.
This discrepancy caused that AFR continued executing requests before
all requests were complete. Eventually, the frame of the pending
request was destroyed when the operation terminated, causing a use-
after-free issue when the answer was finally received.
In theory the same thing could happen in the reverse way, i.e. AFR
tries to wait for more replies than sent requests, causing a hang.
Backport of:
> Upstream-patch-link: https://review.gluster.org/24191
> Change-Id: I7ed6108554ca379d532efb1a29b2de8085410b70
> Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>
> Fixes: bz#1808875
BUG: 1794663
Change-Id: I7ed6108554ca379d532efb1a29b2de8085410b70
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>
Reviewed-on: https://code.engineering.redhat.com/gerrit/202489
Tested-by: RHGS Build Bot <nigelb@redhat.com>
Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <sheggodu@redhat.com>
---
xlators/cluster/afr/src/afr-self-heal-common.c | 6 +++---
xlators/cluster/afr/src/afr-self-heal-name.c | 4 +++-
xlators/cluster/afr/src/afr-self-heal.h | 7 +++++--
3 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index ce1ea50..d942ccf 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -1869,12 +1869,12 @@ int
afr_selfheal_unlocked_discover(call_frame_t *frame, inode_t *inode, uuid_t gfid,
struct afr_reply *replies)
{
- afr_private_t *priv = NULL;
+ afr_local_t *local = NULL;
- priv = frame->this->private;
+ local = frame->local;
return afr_selfheal_unlocked_discover_on(frame, inode, gfid, replies,
- priv->child_up);
+ local->child_up);
}
unsigned int
diff --git a/xlators/cluster/afr/src/afr-self-heal-name.c b/xlators/cluster/afr/src/afr-self-heal-name.c
index 7d4f208..dace071 100644
--- a/xlators/cluster/afr/src/afr-self-heal-name.c
+++ b/xlators/cluster/afr/src/afr-self-heal-name.c
@@ -560,13 +560,15 @@ afr_selfheal_name_unlocked_inspect(call_frame_t *frame, xlator_t *this,
struct afr_reply *replies = NULL;
inode_t *inode = NULL;
int first_idx = -1;
+ afr_local_t *local = NULL;
priv = this->private;
+ local = frame->local;
replies = alloca0(sizeof(*replies) * priv->child_count);
inode = afr_selfheal_unlocked_lookup_on(frame, parent, bname, replies,
- priv->child_up, NULL);
+ local->child_up, NULL);
if (!inode)
return -ENOMEM;
diff --git a/xlators/cluster/afr/src/afr-self-heal.h b/xlators/cluster/afr/src/afr-self-heal.h
index 8234cec..f7ecf5d 100644
--- a/xlators/cluster/afr/src/afr-self-heal.h
+++ b/xlators/cluster/afr/src/afr-self-heal.h
@@ -46,13 +46,16 @@
afr_local_t *__local = frame->local; \
afr_private_t *__priv = frame->this->private; \
int __i = 0; \
- int __count = AFR_COUNT(list, __priv->child_count); \
+ int __count = 0; \
+ unsigned char *__list = alloca(__priv->child_count); \
\
+ memcpy(__list, list, sizeof(*__list) * __priv->child_count); \
+ __count = AFR_COUNT(__list, __priv->child_count); \
__local->barrier.waitfor = __count; \
afr_local_replies_wipe(__local, __priv); \
\
for (__i = 0; __i < __priv->child_count; __i++) { \
- if (!list[__i]) \
+ if (!__list[__i]) \
continue; \
STACK_WIND_COOKIE(frame, rfn, (void *)(long)__i, \
__priv->children[__i], \
--
1.8.3.1