UBIFS: use bit-fields to store compression type
Save a 4 bytes of RAM per 'struct inode' by stroring inode
compression type in bit-filed, instead of using 'int'.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index d80b2ae..21b4103 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2021,6 +2021,14 @@
BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
/*
+ * We use 2 bit wide bit-fields to store compression type, which should
+ * be amended if more compressors are added. The bit-fields are:
+ * @compr_type in 'struct ubifs_inode' and @default_compr in
+ * 'struct ubifs_info'.
+ */
+ BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);
+
+ /*
* We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
* UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
*/