LU-8346 obdclass: guarantee all keys filled

In keys_fill, the key_set_version could be changed after
the keys are filled, then the keys in this context won't
be refilled by the following lu_context_refill for its
verion is equal to the current key_set_verion.

Change-Id: Ibaa49ec6e95ffee902cfa98f18ac9e66f2127bf1
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: https://review.whamcloud.com/26099
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Fan Yong <fan.yong@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 1be5a9d..cc89029 100644 (file)
--- a/lustre/obdclass/lu_object.c
+++ b/lustre/obdclass/lu_object.c
@@ -1615,15 +1615,18 @@ void lu_context_key_quiesce(struct lu_context_key *key)
                list_for_each_entry(ctx, &lu_context_remembered,
                                    lc_remember)
                        key_fini(ctx, key->lct_index);
-               write_unlock(&lu_keys_guard);
+
                ++key_set_version;
+               write_unlock(&lu_keys_guard);
        }
 }
 
 void lu_context_key_revive(struct lu_context_key *key)
 {
-        key->lct_tags &= ~LCT_QUIESCENT;
-        ++key_set_version;
+       write_lock(&lu_keys_guard);
+       key->lct_tags &= ~LCT_QUIESCENT;
+       ++key_set_version;
+       write_unlock(&lu_keys_guard);
 }
 
 static void keys_fini(struct lu_context *ctx)
@@ -1643,6 +1646,7 @@ static void keys_fini(struct lu_context *ctx)
 static int keys_fill(struct lu_context *ctx)
 {
        unsigned int i;
+       unsigned pre_version;
 
        /*
         * A serialisation with lu_context_key_quiesce() is needed, but some
@@ -1655,24 +1659,26 @@ static int keys_fill(struct lu_context *ctx)
         */
        read_lock(&lu_keys_guard);
        atomic_inc(&lu_key_initing_cnt);
+       pre_version = key_set_version;
        read_unlock(&lu_keys_guard);
 
-        LINVRNT(ctx->lc_value != NULL);
-        for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
-                struct lu_context_key *key;
+refill:
+       LINVRNT(ctx->lc_value != NULL);
+       for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
+               struct lu_context_key *key;
 
-                key = lu_keys[i];
-                if (ctx->lc_value[i] == NULL && key != NULL &&
-                    (key->lct_tags & ctx->lc_tags) &&
-                    /*
-                     * Don't create values for a LCT_QUIESCENT key, as this
-                     * will pin module owning a key.
-                     */
-                    !(key->lct_tags & LCT_QUIESCENT)) {
-                        void *value;
-
-                        LINVRNT(key->lct_init != NULL);
-                        LINVRNT(key->lct_index == i);
+               key = lu_keys[i];
+               if (ctx->lc_value[i] == NULL && key != NULL &&
+                   (key->lct_tags & ctx->lc_tags) &&
+                   /*
+                    * Don't create values for a LCT_QUIESCENT key, as this
+                    * will pin module owning a key.
+                    */
+                   !(key->lct_tags & LCT_QUIESCENT)) {
+                       void *value;
+
+                       LINVRNT(key->lct_init != NULL);
+                       LINVRNT(key->lct_index == i);
 
                        LASSERT(key->lct_owner != NULL);
                        if (!(ctx->lc_tags & LCT_NOREF) &&
@@ -1689,19 +1695,27 @@ static int keys_fill(struct lu_context *ctx)
 
                        lu_ref_add_atomic(&key->lct_reference, "ctx", ctx);
                        atomic_inc(&key->lct_used);
-                        /*
-                         * This is the only place in the code, where an
-                         * element of ctx->lc_value[] array is set to non-NULL
-                         * value.
-                         */
-                        ctx->lc_value[i] = value;
-                        if (key->lct_exit != NULL)
-                                ctx->lc_tags |= LCT_HAS_EXIT;
-                }
-                ctx->lc_version = key_set_version;
-        }
+                       /*
+                        * This is the only place in the code, where an
+                        * element of ctx->lc_value[] array is set to non-NULL
+                        * value.
+                        */
+                       ctx->lc_value[i] = value;
+                       if (key->lct_exit != NULL)
+                               ctx->lc_tags |= LCT_HAS_EXIT;
+               }
+       }
+
+       read_lock(&lu_keys_guard);
+       if (pre_version != key_set_version) {
+               pre_version = key_set_version;
+               read_unlock(&lu_keys_guard);
+               goto refill;
+       }
+
        atomic_dec(&lu_key_initing_cnt);
-        return 0;
+       read_unlock(&lu_keys_guard);
+       return 0;
 }
 
 static int keys_init(struct lu_context *ctx)