performance/write-behind: better invalidation in readdirp

Current invalidation of stats in wb_readdirp_cbk is prone to races. As
the deleted comment explains,

<snip>
We cannot guarantee integrity of entry->d_stat as there are cached
writes. The stat is most likely stale as it doesn't account the cached
writes. However, checking for non-empty liability list here is not a
fool-proof solution as there can be races like,
  1. readdirp is successful on posix
  2. sync of cached write is successful on posix
  3. write-behind received sync response and removed the request from
     liability queue
  4. readdirp response is processed at write-behind.

In the above scenario, stat for the file is sent back in readdirp
response but it is stale.
</snip>

Change-Id: I6ce170985cc6ce3df2382ec038dd5415beefded5
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Updates: bz#1512691

1 files changed, 2 insertions, 0 deletions

diff --git a/libglusterfs/src/inode.h b/libglusterfs/src/inode.h
index 658477700c0..96f67c05629 100644
--- a/libglusterfs/src/inode.h
+++ b/libglusterfs/src/inode.h
@@ -60,6 +60,7 @@ struct _inode_table {
 struct _dentry {
         struct list_head   inode_list;   /* list of dentries of inode */
         struct list_head   hash;         /* hash table pointers */
+        struct list_head   parent_list;  /* list of parent's children */
         inode_t           *inode;        /* inode of this directory entry */
         char              *name;         /* name of the directory entry */
         inode_t           *parent;       /* directory of the entry */
@@ -99,6 +100,7 @@ struct _inode {
         struct list_head     dentry_list;   /* list of directory entries for this inode */
         struct list_head     hash;          /* hash table pointers */
         struct list_head     list;          /* active/lru/purge */
+        struct list_head     children;      /* list of children */
 
         struct _inode_ctx   *_ctx;    /* replacement for dict_t *(inode->ctx) */
 };