LU-8346 obdclass: protect key_set_version

In lu_context_refill, the key_set_version should be protected
before comparing it to version stored in the lu_context.

This patch is a supplement of the previous patch
https://review.whamcloud.com/#/c/28405/, which adds protection
for key_set_version from modification in lu_context_refill
and lu_context_key_degister.

Change-Id: I201f56214382a717cfc31ba573e06fec9fbedae4
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: https://review.whamcloud.com/27448
Reviewed-by: Patrick Farrell <paf@cray.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lustre/obdclass/lu_object.c b/lustre/obdclass/lu_object.c
index 543efcc..694bab2 100644 (file)
--- a/lustre/obdclass/lu_object.c
+++ b/lustre/obdclass/lu_object.c
@@ -1408,8 +1408,8 @@ void lu_context_key_degister(struct lu_context_key *key)
 
        lu_context_key_quiesce(key);
 
-       ++key_set_version;
        write_lock(&lu_keys_guard);
+       ++key_set_version;
        key_fini(&lu_shrink_env.le_ctx, key->lct_index);
 
        /**
@@ -1779,7 +1779,14 @@ EXPORT_SYMBOL(lu_context_exit);
  */
 int lu_context_refill(struct lu_context *ctx)
 {
-        return likely(ctx->lc_version == key_set_version) ? 0 : keys_fill(ctx);
+       read_lock(&lu_keys_guard);
+       if (likely(ctx->lc_version == key_set_version)) {
+               read_unlock(&lu_keys_guard);
+               return 0;
+       }
+
+       read_unlock(&lu_keys_guard);
+       return keys_fill(ctx);
 }
 
 /**