LU-4604 obdclass: handle ldt_device_nr/ldt_linkage properly

It is partly back-ported the patch from master:
"LU-4604 lfsck: LFSCK async updates RPC flow control"
But this only contains the part related with lu_device fixes,
not the lfsck async RPC changes.

There was no protection when inc/dec lu_device_type::ldt_device_nr,
which may caused the ldt_device_nr to be wrong and trigger assert.
This patch redefine lu_device_type::ldt_device_nr as atomic type.

There was no protection when add/del lu_device_type::ldt_linkage
into/from the global lu_device_types list, which may caused bad
address accessing. This patch uses the existing obd_types_lock
to protect related operations.

We do NOT need lu_types_stop() any longer. Such function scans
the global lu_device_types list, and for each type item on it
which has zerod lu_device_type::ldt_device_nr, call its stop()
method. In fact, the lu_device_type::ldt_device_nr only will be
zero when the last lu_device_fini() is called, and at that time,
inside the lu_device_fini(), its stop() method will be called.
So it is unnecessary to call the stop() again via lu_types_stop().

Lustre-commit: caef708d4040fd13499a11a42507ba56f9454298
Lustre-change: http://review.whamcloud.com/8694

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ibea9e8f51191de76dbd2e199e01b1d2adff35c75
Reviewed-on: http://review.whamcloud.com/12531
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>

diff --git a/lustre/include/lu_object.h b/lustre/include/lu_object.h
index 991d101..1f26790 100644 (file)
--- a/lustre/include/lu_object.h
+++ b/lustre/include/lu_object.h
@@ -333,7 +333,7 @@ struct lu_device_type {
         /**
          * Number of existing device type instances.
          */
-        unsigned                                ldt_device_nr;
+       atomic_t                                ldt_device_nr;
         /**
          * Linkage into a global list of all device types.
          *
@@ -681,7 +681,6 @@ void lu_dev_del_linkage(struct lu_site *s, struct lu_device *d);
 
 int  lu_device_type_init(struct lu_device_type *ldt);
 void lu_device_type_fini(struct lu_device_type *ldt);
-void lu_types_stop(void);
 
 /** @} ctors */
 

diff --git a/lustre/liblustre/llite_cl.c b/lustre/liblustre/llite_cl.c
index 630be49..2769a0a 100644 (file)
--- a/lustre/liblustre/llite_cl.c
+++ b/lustre/liblustre/llite_cl.c
@@ -786,11 +786,6 @@ int cl_sb_fini(struct llu_sb_info *sbi)
                 sbi->ll_site = NULL;
         }
         cl_env_put(env, &refcheck);
-        /*
-         * If mount failed (sbi->ll_cl == NULL), and this there are no other
-         * mounts, stop device types manually (this usually happens
-         * automatically when last device is destroyed).
-         */
-        lu_types_stop();
-        RETURN(0);
+
+       RETURN(0);
 }

diff --git a/lustre/llite/vvp_dev.c b/lustre/llite/vvp_dev.c
index d70a40b..9562f4e 100644 (file)
--- a/lustre/llite/vvp_dev.c
+++ b/lustre/llite/vvp_dev.c
@@ -244,13 +244,8 @@ int cl_sb_fini(struct super_block *sb)
                 CERROR("Cannot cleanup cl-stack due to memory shortage.\n");
                 result = PTR_ERR(env);
         }
-        /*
-         * If mount failed (sbi->ll_cl == NULL), and this there are no other
-         * mounts, stop device types manually (this usually happens
-         * automatically when last device is destroyed).
-         */
-        lu_types_stop();
-        RETURN(result);
+
+       RETURN(result);
 }
 
 /****************************************************************************

diff --git a/lustre/obdclass/lu_object.c b/lustre/obdclass/lu_object.c
index 0b8df84..ed44efa 100644 (file)
--- a/lustre/obdclass/lu_object.c
+++ b/lustre/obdclass/lu_object.c
@@ -92,6 +92,8 @@ CFS_MODULE_PARM(lu_cache_nr, "l", long, 0644,
 
 static void lu_object_free(const struct lu_env *env, struct lu_object *o);
 
+extern spinlock_t obd_types_lock;
+
 /**
  * Decrease reference counter on object. If last reference is freed, return
  * object to the cache, unless lu_object_is_dying(o) holds. In the latter
@@ -862,34 +864,30 @@ int lu_device_type_init(struct lu_device_type *ldt)
 {
        int result = 0;
 
+       atomic_set(&ldt->ldt_device_nr, 0);
        CFS_INIT_LIST_HEAD(&ldt->ldt_linkage);
        if (ldt->ldt_ops->ldto_init)
                result = ldt->ldt_ops->ldto_init(ldt);
-       if (result == 0)
+
+       if (result == 0) {
+               spin_lock(&obd_types_lock);
                cfs_list_add(&ldt->ldt_linkage, &lu_device_types);
+               spin_unlock(&obd_types_lock);
+       }
        return result;
 }
 EXPORT_SYMBOL(lu_device_type_init);
 
 void lu_device_type_fini(struct lu_device_type *ldt)
 {
+       spin_lock(&obd_types_lock);
        cfs_list_del_init(&ldt->ldt_linkage);
+       spin_unlock(&obd_types_lock);
        if (ldt->ldt_ops->ldto_fini)
                ldt->ldt_ops->ldto_fini(ldt);
 }
 EXPORT_SYMBOL(lu_device_type_fini);
 
-void lu_types_stop(void)
-{
-        struct lu_device_type *ldt;
-
-       cfs_list_for_each_entry(ldt, &lu_device_types, ldt_linkage) {
-               if (ldt->ldt_device_nr == 0 && ldt->ldt_ops->ldto_stop)
-                       ldt->ldt_ops->ldto_stop(ldt);
-       }
-}
-EXPORT_SYMBOL(lu_types_stop);
-
 /**
  * Global list of all sites on this node
  */
@@ -1224,14 +1222,15 @@ EXPORT_SYMBOL(lu_device_put);
  */
 int lu_device_init(struct lu_device *d, struct lu_device_type *t)
 {
-        if (t->ldt_device_nr++ == 0 && t->ldt_ops->ldto_start != NULL)
-                t->ldt_ops->ldto_start(t);
-        memset(d, 0, sizeof *d);
-        cfs_atomic_set(&d->ld_ref, 0);
-        d->ld_type = t;
-        lu_ref_init(&d->ld_reference);
-        CFS_INIT_LIST_HEAD(&d->ld_linkage);
-        return 0;
+       if (atomic_inc_return(&t->ldt_device_nr) == 1 &&
+           t->ldt_ops->ldto_start != NULL)
+               t->ldt_ops->ldto_start(t);
+
+       memset(d, 0, sizeof *d);
+       d->ld_type = t;
+       lu_ref_init(&d->ld_reference);
+       CFS_INIT_LIST_HEAD(&d->ld_linkage);
+       return 0;
 }
 EXPORT_SYMBOL(lu_device_init);
 
@@ -1251,9 +1250,11 @@ void lu_device_fini(struct lu_device *d)
         lu_ref_fini(&d->ld_reference);
         LASSERTF(cfs_atomic_read(&d->ld_ref) == 0,
                  "Refcount is %u\n", cfs_atomic_read(&d->ld_ref));
-        LASSERT(t->ldt_device_nr > 0);
-        if (--t->ldt_device_nr == 0 && t->ldt_ops->ldto_stop != NULL)
-                t->ldt_ops->ldto_stop(t);
+       LASSERT(atomic_read(&t->ldt_device_nr) > 0);
+
+       if (atomic_dec_and_test(&t->ldt_device_nr) &&
+           t->ldt_ops->ldto_stop != NULL)
+               t->ldt_ops->ldto_stop(t);
 }
 EXPORT_SYMBOL(lu_device_fini);
 

diff --git a/lustre/obdclass/obd_mount.c b/lustre/obdclass/obd_mount.c
index 4dba8c2..28614fa 100644 (file)
--- a/lustre/obdclass/obd_mount.c
+++ b/lustre/obdclass/obd_mount.c
@@ -819,8 +819,7 @@ int lustre_common_put_super(struct super_block *sb)
         }
         /* Drop a ref to the mounted disk */
         lustre_put_lsi(sb);
-        lu_types_stop();
-        RETURN(rc);
+       RETURN(rc);
 }
 EXPORT_SYMBOL(lustre_common_put_super);