Make ZFS filesystem id persistent across different machines

[zfs.git] / module / zfs / dmu_objset.c

diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index 1dcfb02..a34584e 100644 (file)
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -262,7 +262,7 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 
        ASSERT(ds == NULL || MUTEX_HELD(&ds->ds_opening_lock));
 
-       os = kmem_zalloc(sizeof (objset_t), KM_SLEEP);
+       os = kmem_zalloc(sizeof (objset_t), KM_PUSHPAGE);
        os->os_dsl_dataset = ds;
        os->os_spa = spa;
        os->os_rootbp = bp;
@@ -1584,6 +1584,41 @@ dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
        return (0);
 }
 
+/*
+ * Determine the objset id for a given snapshot name.
+ */
+int
+dmu_snapshot_id(objset_t *os, const char *snapname, uint64_t *idp)
+{
+       dsl_dataset_t *ds = os->os_dsl_dataset;
+       zap_cursor_t cursor;
+       zap_attribute_t attr;
+       int error;
+
+       if (ds->ds_phys->ds_snapnames_zapobj == 0)
+               return (ENOENT);
+
+       zap_cursor_init(&cursor, ds->ds_dir->dd_pool->dp_meta_objset,
+           ds->ds_phys->ds_snapnames_zapobj);
+
+       error = zap_cursor_move_to_key(&cursor, snapname, MT_EXACT);
+       if (error) {
+               zap_cursor_fini(&cursor);
+               return (error);
+       }
+
+       error = zap_cursor_retrieve(&cursor, &attr);
+       if (error) {
+               zap_cursor_fini(&cursor);
+               return (error);
+       }
+
+       *idp = attr.za_first_integer;
+       zap_cursor_fini(&cursor);
+
+       return (0);
+}
+
 int
 dmu_dir_list_next(objset_t *os, int namelen, char *name,
     uint64_t *idp, uint64_t *offp)
@@ -1796,3 +1831,43 @@ dmu_objset_get_user(objset_t *os)
        ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
        return (os->os_user_ptr);
 }
+
+#if defined(_KERNEL) && defined(HAVE_SPL)
+EXPORT_SYMBOL(dmu_objset_zil);
+EXPORT_SYMBOL(dmu_objset_pool);
+EXPORT_SYMBOL(dmu_objset_ds);
+EXPORT_SYMBOL(dmu_objset_type);
+EXPORT_SYMBOL(dmu_objset_name);
+EXPORT_SYMBOL(dmu_objset_hold);
+EXPORT_SYMBOL(dmu_objset_own);
+EXPORT_SYMBOL(dmu_objset_rele);
+EXPORT_SYMBOL(dmu_objset_disown);
+EXPORT_SYMBOL(dmu_objset_from_ds);
+EXPORT_SYMBOL(dmu_objset_create);
+EXPORT_SYMBOL(dmu_objset_clone);
+EXPORT_SYMBOL(dmu_objset_destroy);
+EXPORT_SYMBOL(dmu_objset_snapshot);
+EXPORT_SYMBOL(dmu_objset_stats);
+EXPORT_SYMBOL(dmu_objset_fast_stat);
+EXPORT_SYMBOL(dmu_objset_spa);
+EXPORT_SYMBOL(dmu_objset_space);
+EXPORT_SYMBOL(dmu_objset_fsid_guid);
+EXPORT_SYMBOL(dmu_objset_find);
+EXPORT_SYMBOL(dmu_objset_find_spa);
+EXPORT_SYMBOL(dmu_objset_prefetch);
+EXPORT_SYMBOL(dmu_objset_byteswap);
+EXPORT_SYMBOL(dmu_objset_evict_dbufs);
+EXPORT_SYMBOL(dmu_objset_snap_cmtime);
+
+EXPORT_SYMBOL(dmu_objset_sync);
+EXPORT_SYMBOL(dmu_objset_is_dirty);
+EXPORT_SYMBOL(dmu_objset_create_impl);
+EXPORT_SYMBOL(dmu_objset_open_impl);
+EXPORT_SYMBOL(dmu_objset_evict);
+EXPORT_SYMBOL(dmu_objset_register_type);
+EXPORT_SYMBOL(dmu_objset_do_userquota_updates);
+EXPORT_SYMBOL(dmu_objset_userquota_get_ids);
+EXPORT_SYMBOL(dmu_objset_userused_enabled);
+EXPORT_SYMBOL(dmu_objset_userspace_upgrade);
+EXPORT_SYMBOL(dmu_objset_userspace_present);
+#endif