LU-2332 osc: solve a race in client obd list lock

[fs/lustre-release.git] / lustre / osc / osc_cache.c

diff --git a/lustre/osc/osc_cache.c b/lustre/osc/osc_cache.c
index df7fb1e..469de7f 100644 (file)
--- a/lustre/osc/osc_cache.c
+++ b/lustre/osc/osc_cache.c
@@ -27,7 +27,7 @@
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011 Whamcloud, Inc.
+ * Copyright (c) 2012, Intel Corporation.
  *
  */
 /*
@@ -1393,8 +1393,6 @@ static void __osc_unreserve_grant(struct client_obd *cli,
        } else {
                cli->cl_avail_grant += unused;
        }
-       if (unused > 0)
-               osc_wake_cache_waiters(cli);
 }
 
 void osc_unreserve_grant(struct client_obd *cli,
@@ -1402,6 +1400,8 @@ void osc_unreserve_grant(struct client_obd *cli,
 {
        client_obd_list_lock(&cli->cl_loi_list_lock);
        __osc_unreserve_grant(cli, reserved, unused);
+       if (unused > 0)
+               osc_wake_cache_waiters(cli);
        client_obd_list_unlock(&cli->cl_loi_list_lock);
 }
 
@@ -1440,12 +1440,15 @@ static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
               cli->cl_avail_grant, cli->cl_dirty);
 }
 
-/* The companion to osc_enter_cache(), called when @oap is no longer part of
- * the dirty accounting.  Writeback completes or truncate happens before
- * writing starts.  Must be called with the loi lock held. */
+/**
+ * The companion to osc_enter_cache(), called when @oap is no longer part of
+ * the dirty accounting due to error.
+ */
 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
 {
+       client_obd_list_lock(&cli->cl_loi_list_lock);
        osc_release_write_grant(cli, &oap->oap_brw_page);
+       client_obd_list_unlock(&cli->cl_loi_list_lock);
 }
 
 /**
@@ -1480,8 +1483,13 @@ static int osc_enter_cache_try(struct client_obd *cli,
        return rc;
 }
 
-/* Caller must hold loi_list_lock - we drop/regain it if we need to wait for
- * grant or cache space. */
+/**
+ * The main entry to reserve dirty page accounting. Usually the grant reserved
+ * in this function will be freed in bulk in osc_free_grant() unless it fails
+ * to add osc cache, in that case, it will be freed in osc_exit_cache().
+ *
+ * The process will be put into sleep if it's already run out of grant.
+ */
 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
                           struct osc_async_page *oap, int bytes)
 {