staging/lustre/scrub: purge inconsistenct objects after OI scrub

When OI scrub repaired the found inconsistency, it needs to purge the
old object out of cache; otherwise, others may still use those cached
stale information.

Original patch adds functions in obdclass that is only used by server.
Drop that part. Only merge in error handling change.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3335
Lustre-change: http://review.whamcloud.com/6697
Signed-off-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/lu_object.c

@@ -538,7 +538,7 @@ static struct lu_object *htable_lookup(struct lu_site *s,
 	__u64  ver = cfs_hash_bd_version_get(bd);
 
 	if (*version == ver)
-		return NULL;
+		return ERR_PTR(-ENOENT);
 
 	*version = ver;
 	bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, bd);
@@ -547,7 +547,7 @@ static struct lu_object *htable_lookup(struct lu_site *s,
 	hnode = cfs_hash_bd_peek_locked(s->ls_obj_hash, bd, (void *)f);
 	if (hnode == NULL) {
 		lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_MISS);
-		return NULL;
+		return ERR_PTR(-ENOENT);
 	}
 
 	h = container_of0(hnode, struct lu_object_header, loh_hash);
@@ -651,7 +651,7 @@ static struct lu_object *lu_object_find_try(const struct lu_env *env,
 	cfs_hash_bd_get_and_lock(hs, (void *)f, &bd, 1);
 	o = htable_lookup(s, &bd, f, waiter, &version);
 	cfs_hash_bd_unlock(hs, &bd, 1);
-	if (o != NULL)
+	if (!IS_ERR(o) || PTR_ERR(o) != -ENOENT)
 		return o;
 
 	/*
@@ -667,7 +667,7 @@ static struct lu_object *lu_object_find_try(const struct lu_env *env,
 	cfs_hash_bd_lock(hs, &bd, 1);
 
 	shadow = htable_lookup(s, &bd, f, waiter, &version);
-	if (likely(shadow == NULL)) {
+	if (likely(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT)) {
 		struct lu_site_bkt_data *bkt;
 
 		bkt = cfs_hash_bd_extra_get(hs, &bd);
@@ -2076,7 +2076,7 @@ void lu_object_assign_fid(const struct lu_env *env, struct lu_object *o,
 	cfs_hash_bd_get_and_lock(hs, (void *)fid, &bd, 1);
 	shadow = htable_lookup(s, &bd, fid, &waiter, &version);
 	/* supposed to be unique */
-	LASSERT(shadow == NULL);
+	LASSERT(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT);
 	*old = *fid;
 	bkt = cfs_hash_bd_extra_get(hs, &bd);
 	cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);