udf: Skip mirror metadata FE loading when metadata FE is ok

It is not necessary to load mirror metadata FE when metadata FE is OK.  So try
to read it only the first time udf_get_pblock_meta25() fails to map the block
from metadata FE.

Signed-off-by: Ashish Sangwan <ashishsangwan2@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index f3d4498..79aae3f 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -135,6 +135,8 @@
 	UDF_SB(sb)->s_lvid_dirty = 1;
 }
 extern u64 lvid_get_unique_id(struct super_block *sb);
+struct inode *udf_find_metadata_inode_efe(struct super_block *sb,
+					u32 meta_file_loc, u32 partition_num);
 
 /* namei.c */
 extern int udf_write_fi(struct inode *inode, struct fileIdentDesc *,