From d005ede12e1da99dc077bf9e1c563a0f9f4066e3 Mon Sep 17 00:00:00 2001
From: Pranith Kumar K <pkarampu@redhat.com>
Date: Mon, 19 Mar 2018 12:09:18 +0530
Subject: [PATCH 667/675] features/shard: Do list_del_init() while list memory
 is valid

> Upstream: https://review.gluster.org/19737
> BUG: 1557876
> Change-Id: If429d3634219e1a435bd0da0ed985c646c59c2ca

Problem:
shard_post_lookup_fsync_handler() goes over the list of inode-ctx that need to
be fsynced and in cbk it removes each of the inode-ctx from the list. When the
first member of list is removed it tries to modifies list head's memory with
the latest next/prev and when this happens, there is no guarantee that the
list-head which is from stack memory of shard_post_lookup_fsync_handler() is
valid.

Fix:
Do list_del_init() in the loop before winding fsync.

Change-Id: If429d3634219e1a435bd0da0ed985c646c59c2ca
BUG: 1585046
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: https://code.engineering.redhat.com/gerrit/140483
Tested-by: Krutika Dhananjay <kdhananj@redhat.com>
Tested-by: RHGS Build Bot <nigelb@redhat.com>
Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <sheggodu@redhat.com>
---
 xlators/features/shard/src/shard.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xlators/features/shard/src/shard.c b/xlators/features/shard/src/shard.c
index 68d1a3a..651d08a 100644
--- a/xlators/features/shard/src/shard.c
+++ b/xlators/features/shard/src/shard.c
@@ -4525,7 +4525,6 @@ out:
                         if (op_ret == 0)
                                 ctx->fsync_needed -= fsync_count;
                         GF_ASSERT (ctx->fsync_needed >= 0);
-                        list_del_init (&ctx->to_fsync_list);
                         if (ctx->fsync_needed != 0) {
                                 list_add_tail (&ctx->to_fsync_list,
                                                &base_ictx->to_fsync_list);
@@ -4600,6 +4599,7 @@ shard_post_lookup_fsync_handler (call_frame_t *frame, xlator_t *this)
         anon_fd = NULL;
 
         list_for_each_entry_safe (iter, tmp, &copy, to_fsync_list) {
+                list_del_init (&iter->to_fsync_list);
                 fsync_count = 0;
                 shard_inode_ctx_get_fsync_count (iter->inode, this,
                                                  &fsync_count);
-- 
1.8.3.1