LU-8066 obd_type: discard obd_types linked list.

As all obd_types are kobjects in the lustre_kset kset,
they are linked together in that kset and don't
need any extra linkage.

There are non-obd_type objects in lustre_kset, added by
class_setup_tunables().  These have a different ->ktype, so we are
careful to only return objects with the correct ->ktype.

As kset_find_obj() returns a counted reference, we need
to put that reference when done.

On the server side it is possible to have an obd_type partially
initialized by one subsystem and latter fully initialized by
another subsystem. We use typ_sym_filter to notify us if the
obd_type is only partially setup. If it only paritially setup
then we let the original subsystem that created the obd_type
to clean it up. If the obd_type was latter completely setup
then we let the latter subsystem do the cleanup for us.

Linux-commit: 881bc9b58ef5e8c9be297b121187ea6c26572cf1

Change-Id: I4316644f7fb12e358b799af64deb57836e796066
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-on: https://review.whamcloud.com/34718
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Alexandr Boyko <c17825@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index 9cdf306..c43cafb 100644 (file)
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -99,7 +99,6 @@ struct obd_info {
 };
 
 struct obd_type {
-       struct list_head         typ_chain;
        struct obd_ops          *typ_dt_ops;
        struct md_ops           *typ_md_ops;
        struct proc_dir_entry   *typ_procroot;

diff --git a/lustre/include/obd_class.h b/lustre/include/obd_class.h
index 29728e6..11ddb0e 100644 (file)
--- a/lustre/include/obd_class.h
+++ b/lustre/include/obd_class.h
@@ -359,8 +359,10 @@ void class_import_put(struct obd_import *);
 struct obd_import *class_new_import(struct obd_device *obd);
 void class_destroy_import(struct obd_import *exp);
 
+#ifdef HAVE_SERVER_SUPPORT
 struct obd_type *class_search_type(const char *name);
 struct obd_type *class_get_type(const char *name);
+#endif
 void class_put_type(struct obd_type *type);
 int class_connect(struct lustre_handle *conn, struct obd_device *obd,
                   struct obd_uuid *cluuid);

diff --git a/lustre/lod/lod_dev.c b/lustre/lod/lod_dev.c
index a452e5d..99ccbb0 100644 (file)
--- a/lustre/lod/lod_dev.c
+++ b/lustre/lod/lod_dev.c
@@ -2166,10 +2166,9 @@ static struct obd_ops lod_obd_device_ops = {
        .o_pool_del     = lod_pool_del,
 };
 
-static struct obd_type *sym;
-
 static int __init lod_init(void)
 {
+       struct obd_type *sym;
        int rc;
 
        rc = lu_kmem_init(lod_caches);
@@ -2197,8 +2196,18 @@ static int __init lod_init(void)
 
 static void __exit lod_exit(void)
 {
-       if (!IS_ERR_OR_NULL(sym))
+       struct obd_type *sym = class_search_type(LUSTRE_LOV_NAME);
+
+       /* if this was never fully initialized by the lov layer
+        * then we are responsible for freeing this obd_type
+        */
+       if (sym) {
+               /* final put if we manage this obd type */
+               if (sym->typ_sym_filter)
+                       kobject_put(&sym->typ_kobj);
+               /* put reference taken by class_search_type */
                kobject_put(&sym->typ_kobj);
+       }
 
        class_unregister_type(LUSTRE_LOD_NAME);
        lu_kmem_fini(lod_caches);

diff --git a/lustre/mdd/mdd_lproc.c b/lustre/mdd/mdd_lproc.c
index f18a6ff..829afc7 100644 (file)
--- a/lustre/mdd/mdd_lproc.c
+++ b/lustre/mdd/mdd_lproc.c
@@ -702,6 +702,9 @@ int mdd_procfs_init(struct mdd_device *mdd, const char *name)
        LASSERT(type != NULL);
        LASSERT(obd  != NULL);
 
+       /* put reference taken by class_search_type */
+       kobject_put(&type->typ_kobj);
+
        mdd->mdd_ktype.default_attrs = mdd_attrs;
        mdd->mdd_ktype.release = mdd_sysfs_release;
        mdd->mdd_ktype.sysfs_ops = &lustre_sysfs_ops;

diff --git a/lustre/obdclass/genops.c b/lustre/obdclass/genops.c
index df1a31d..e622041 100644 (file)
--- a/lustre/obdclass/genops.c
+++ b/lustre/obdclass/genops.c
@@ -46,13 +46,11 @@
 #include <lustre_disk.h>
 #include <lustre_kernelcomm.h>
 
-static DEFINE_SPINLOCK(obd_types_lock);
-static LIST_HEAD(obd_types);
 DEFINE_RWLOCK(obd_dev_lock);
 static struct obd_device *obd_devs[MAX_OBD_DEVICES];
 
 static struct kmem_cache *obd_device_cachep;
-
+static struct kobj_type class_ktype;
 static struct workqueue_struct *zombie_wq;
 
 static void obd_zombie_export_add(struct obd_export *exp);
@@ -98,30 +96,26 @@ static void obd_device_free(struct obd_device *obd)
 
 struct obd_type *class_search_type(const char *name)
 {
-       struct list_head *tmp;
-       struct obd_type *type;
+       struct kobject *kobj = kset_find_obj(lustre_kset, name);
 
-       spin_lock(&obd_types_lock);
-       list_for_each(tmp, &obd_types) {
-               type = list_entry(tmp, struct obd_type, typ_chain);
-               if (strcmp(type->typ_name, name) == 0) {
-                       spin_unlock(&obd_types_lock);
-                       return type;
-               }
-       }
-       spin_unlock(&obd_types_lock);
+       if (kobj && kobj->ktype == &class_ktype)
+               return container_of(kobj, struct obd_type, typ_kobj);
+
+       kobject_put(kobj);
        return NULL;
 }
 EXPORT_SYMBOL(class_search_type);
 
 struct obd_type *class_get_type(const char *name)
 {
-        struct obd_type *type = class_search_type(name);
+       struct obd_type *type;
 
+       type = class_search_type(name);
 #ifdef HAVE_MODULE_LOADING_SUPPORT
         if (!type) {
                 const char *modname = name;
 
+#ifdef HAVE_SERVER_SUPPORT
                if (strcmp(modname, "obdfilter") == 0)
                        modname = "ofd";
 
@@ -130,6 +124,7 @@ struct obd_type *class_get_type(const char *name)
 
                if (!strncmp(modname, LUSTRE_MDS_NAME, strlen(LUSTRE_MDS_NAME)))
                        modname = LUSTRE_MDT_NAME;
+#endif /* HAVE_SERVER_SUPPORT */
 
                if (!request_module("%s", modname)) {
                        CDEBUG(D_INFO, "Loaded module '%s'\n", modname);
@@ -145,6 +140,11 @@ struct obd_type *class_get_type(const char *name)
                type->typ_refcnt++;
                try_module_get(type->typ_dt_ops->o_owner);
                spin_unlock(&type->obd_type_lock);
+               /* class_search_type() returned a counted reference,
+                * but we don't need that count any more as
+                * we have one through typ_refcnt.
+                */
+               kobject_put(&type->typ_kobj);
        }
        return type;
 }
@@ -162,20 +162,12 @@ static void class_sysfs_release(struct kobject *kobj)
 {
        struct obd_type *type = container_of(kobj, struct obd_type, typ_kobj);
 
-#ifdef HAVE_SERVER_SUPPORT
-       if (type->typ_sym_filter)
-               type->typ_debugfs_entry = NULL;
-#endif
        debugfs_remove_recursive(type->typ_debugfs_entry);
        type->typ_debugfs_entry = NULL;
 
        if (type->typ_lu)
                lu_device_type_fini(type->typ_lu);
 
-       spin_lock(&obd_types_lock);
-       list_del(&type->typ_chain);
-       spin_unlock(&obd_types_lock);
-
 #ifdef CONFIG_PROC_FS
        if (type->typ_name && type->typ_procroot)
                remove_proc_subtree(type->typ_name, proc_lustre_root);
@@ -198,12 +190,11 @@ struct obd_type *class_add_symlinks(const char *name, bool enable_proc)
 {
        struct dentry *symlink;
        struct obd_type *type;
-       struct kobject *kobj;
        int rc;
 
-       kobj = kset_find_obj(lustre_kset, name);
-       if (kobj) {
-               kobject_put(kobj);
+       type = class_search_type(name);
+       if (type) {
+               kobject_put(&type->typ_kobj);
                return ERR_PTR(-EEXIST);
        }
 
@@ -211,8 +202,6 @@ struct obd_type *class_add_symlinks(const char *name, bool enable_proc)
        if (!type)
                return ERR_PTR(-ENOMEM);
 
-       INIT_LIST_HEAD(&type->typ_chain);
-
        type->typ_kobj.kset = lustre_kset;
        rc = kobject_init_and_add(&type->typ_kobj, &class_ktype,
                                  &lustre_kset->kobj, "%s", name);
@@ -256,20 +245,13 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
        /* sanity check */
        LASSERT(strnlen(name, CLASS_MAX_NAME) < CLASS_MAX_NAME);
 
-        if (class_search_type(name)) {
+       type = class_search_type(name);
+       if (type) {
 #ifdef HAVE_SERVER_SUPPORT
-               if (strcmp(name, LUSTRE_LOV_NAME) == 0 ||
-                   strcmp(name, LUSTRE_OSC_NAME) == 0) {
-                       struct kobject *kobj;
-
-                       kobj = kset_find_obj(lustre_kset, name);
-                       if (kobj) {
-                               type = container_of(kobj, struct obd_type,
-                                                   typ_kobj);
-                               goto dir_exist;
-                       }
-               }
+               if (type->typ_sym_filter)
+                       goto dir_exist;
 #endif /* HAVE_SERVER_SUPPORT */
+               kobject_put(&type->typ_kobj);
                 CDEBUG(D_IOCTL, "Type %s already registered\n", name);
                 RETURN(-EEXIST);
         }
@@ -278,7 +260,6 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
         if (type == NULL)
                RETURN(-ENOMEM);
 
-       INIT_LIST_HEAD(&type->typ_chain);
        type->typ_kobj.kset = lustre_kset;
        kobject_init(&type->typ_kobj, &class_ktype);
 #ifdef HAVE_SERVER_SUPPORT
@@ -298,8 +279,11 @@ dir_exist:
        spin_lock_init(&type->obd_type_lock);
 
 #ifdef HAVE_SERVER_SUPPORT
-       if (type->typ_sym_filter)
+       if (type->typ_sym_filter) {
+               type->typ_sym_filter = false;
+               kobject_put(&type->typ_kobj);
                goto setup_ldt;
+       }
 #endif
 #ifdef CONFIG_PROC_FS
        if (enable_proc && !type->typ_procroot) {
@@ -335,10 +319,6 @@ setup_ldt:
                        GOTO(failed, rc);
        }
 
-       spin_lock(&obd_types_lock);
-       list_add(&type->typ_chain, &obd_types);
-       spin_unlock(&obd_types_lock);
-
        RETURN(0);
 
 failed:
@@ -351,6 +331,7 @@ EXPORT_SYMBOL(class_register_type);
 int class_unregister_type(const char *name)
 {
         struct obd_type *type = class_search_type(name);
+       int rc = 0;
         ENTRY;
 
         if (!type) {
@@ -364,12 +345,16 @@ int class_unregister_type(const char *name)
                 /* Remove ops, but leave the name for debugging */
                 OBD_FREE_PTR(type->typ_dt_ops);
                 OBD_FREE_PTR(type->typ_md_ops);
-                RETURN(-EBUSY);
+               GOTO(out_put, rc = -EBUSY);
         }
 
+       /* Put the final ref */
+       kobject_put(&type->typ_kobj);
+out_put:
+       /* Put the ref returned by class_search_type() */
        kobject_put(&type->typ_kobj);
 
-       RETURN(0);
+       RETURN(rc);
 } /* class_unregister_type */
 EXPORT_SYMBOL(class_unregister_type);
 

diff --git a/lustre/obdclass/obd_mount_server.c b/lustre/obdclass/obd_mount_server.c
index 8ca8180..5b5cb20 100644 (file)
--- a/lustre/obdclass/obd_mount_server.c
+++ b/lustre/obdclass/obd_mount_server.c
@@ -1110,6 +1110,9 @@ static int server_stop_servers(int lsiflags)
                rc = class_manual_cleanup(obd);
        }
 
+       /* put reference taken by class_search_type */
+       kobject_put(&type->typ_kobj);
+
        mutex_unlock(&server_start_lock);
 
        RETURN(rc);

diff --git a/lustre/osd-ldiskfs/osd_internal.h b/lustre/osd-ldiskfs/osd_internal.h
index c29e53d..fe9c8f0 100644 (file)
--- a/lustre/osd-ldiskfs/osd_internal.h
+++ b/lustre/osd-ldiskfs/osd_internal.h
@@ -55,7 +55,7 @@
 
 /* LUSTRE_OSD_NAME */
 #include <obd.h>
-/* class_register_type(), class_unregister_type(), class_get_type() */
+/* class_register_type(), class_unregister_type() */
 #include <obd_class.h>
 #include <lustre_disk.h>
 #include <dt_object.h>

diff --git a/lustre/osd-ldiskfs/osd_lproc.c b/lustre/osd-ldiskfs/osd_lproc.c
index cba3a82..80dc25f 100644 (file)
--- a/lustre/osd-ldiskfs/osd_lproc.c
+++ b/lustre/osd-ldiskfs/osd_lproc.c
@@ -729,6 +729,9 @@ int osd_procfs_init(struct osd_device *osd, const char *name)
 
        LCONSOLE_INFO("osd-ldiskfs create tunables for %s\n", name);
 
+       /* put reference taken by class_search_type */
+       kobject_put(&type->typ_kobj);
+
        osd->od_dt_dev.dd_ktype.default_attrs = ldiskfs_attrs;
        rc = dt_tunables_init(&osd->od_dt_dev, type, name,
                              lprocfs_osd_obd_vars);

diff --git a/lustre/osd-zfs/osd_lproc.c b/lustre/osd-zfs/osd_lproc.c
index a1becc1..1516e58 100644 (file)
--- a/lustre/osd-zfs/osd_lproc.c
+++ b/lustre/osd-zfs/osd_lproc.c
@@ -437,6 +437,9 @@ int osd_procfs_init(struct osd_device *osd, const char *name)
        LASSERT(type);
        LASSERT(name);
 
+       /* put reference taken by class_search_type */
+       kobject_put(&type->typ_kobj);
+
        osd->od_dt_dev.dd_ktype.default_attrs = zfs_attrs;
        rc = dt_tunables_init(&osd->od_dt_dev, type, name,
                              lprocfs_osd_obd_vars);

diff --git a/lustre/osp/osp_dev.c b/lustre/osp/osp_dev.c
index dc3249b..eb768d4 100644 (file)
--- a/lustre/osp/osp_dev.c
+++ b/lustre/osp/osp_dev.c
@@ -1887,8 +1887,6 @@ static struct obd_ops osp_obd_device_ops = {
        .o_fid_alloc    = osp_fid_alloc,
 };
 
-static struct obd_type *sym;
-
 /**
  * Initialize OSP module.
  *
@@ -1903,6 +1901,7 @@ static struct obd_type *sym;
  */
 static int __init osp_init(void)
 {
+       struct obd_type *sym;
        int rc;
 
        rc = lu_kmem_init(osp_caches);
@@ -1925,7 +1924,7 @@ static int __init osp_init(void)
        }
 
        /* create "osc" entry for compatibility purposes */
-       sym = class_add_symlinks(LUSTRE_OSC_NAME, false);
+       sym = class_add_symlinks(LUSTRE_OSC_NAME, true);
        if (IS_ERR(sym)) {
                rc = PTR_ERR(sym);
                /* does real "osc" already exist ? */
@@ -1944,8 +1943,18 @@ static int __init osp_init(void)
  */
 static void __exit osp_exit(void)
 {
-       if (!IS_ERR_OR_NULL(sym))
+       struct obd_type *sym = class_search_type(LUSTRE_OSC_NAME);
+
+       /* if this was never fully initialized by the osc layer
+        * then we are responsible for freeing this obd_type
+        */
+       if (sym) {
+               /* final put if we manage this obd type */
+               if (sym->typ_sym_filter)
+                       kobject_put(&sym->typ_kobj);
+               /* put reference taken by class_search_type */
                kobject_put(&sym->typ_kobj);
+       }
 
        class_unregister_type(LUSTRE_LWP_NAME);
        class_unregister_type(LUSTRE_OSP_NAME);

diff --git a/lustre/quota/qmt_dev.c b/lustre/quota/qmt_dev.c
index fe65065..19605fa 100644 (file)
--- a/lustre/quota/qmt_dev.c
+++ b/lustre/quota/qmt_dev.c
@@ -259,6 +259,9 @@ static int qmt_device_init0(const struct lu_env *env, struct qmt_device *qmt,
        type = class_search_type(LUSTRE_QMT_NAME);
        LASSERT(type != NULL);
 
+       /* put reference taken by class_search_type */
+       kobject_put(&type->typ_kobj);
+
        /* register proc directory associated with this qmt */
        qmt->qmt_proc = lprocfs_register(qmt->qmt_svname, type->typ_procroot,
                                         NULL, NULL);