eulerfs: fix null-ptr-dereference when allocate page failed

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I78RYS
CVE: NA

--------------------------------

Currently, the caller of eufs_alloc_page() and eufs_zalloc_page() expect
that allocation won't fail, otherwise null_ptr_dereference will be
triggered.

Fix this problem by adding flag __GFP_NOFAIL.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

fs/eulerfs/kmem_cache.c

@@ -77,11 +77,11 @@ void destroy_dep_node_cache(void)
 
 void *eufs_zalloc_page(void)
 {
-	return kmem_cache_zalloc(eufs_page_cachep, GFP_NOFS);
+	return kmem_cache_zalloc(eufs_page_cachep, GFP_NOFS | __GFP_NOFAIL);
 }
 void *eufs_alloc_page(void)
 {
-	return kmem_cache_alloc(eufs_page_cachep, GFP_NOFS);
+	return kmem_cache_alloc(eufs_page_cachep, GFP_NOFS | __GFP_NOFAIL);
 }
 void eufs_free_page(void *page)
 {