[PATCH 05/16] ext4: Create a rocompat flag for extended metadata checksumming

["Darrick J. Wong" <djwong@us.ibm.com>]

This patch introduces a rocompat feature flag to signal the presence of
checksums for metadata blocks.  It also pulls in CRC32c since we'll be
using that for the new checksums.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---
 fs/ext4/Kconfig |    1 +
 fs/ext4/ext4.h  |    4 +++-
 2 files changed, 4 insertions(+), 1 deletions(-)


diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index 9ed1bb1..97f4a7d 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -2,6 +2,7 @@ config EXT4_FS
 	tristate "The Extended 4 (ext4) filesystem"
 	select JBD2
 	select CRC16
+	select LIBCRC32C
 	help
 	  This is the next generation of the ext3 filesystem.
 
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ecb86c2..f79ddac 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1359,6 +1359,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
 #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
 #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
 #define EXT4_FEATURE_RO_COMPAT_QUOTA		0x0100
+#define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM	0x0400
 
 #define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
 #define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002
@@ -1401,7 +1402,8 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
 					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \
 					 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \
 					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR |\
-					 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)
+					 EXT4_FEATURE_RO_COMPAT_HUGE_FILE |\
+					 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)
 
 /*
  * Default values for user and/or group using reserved blocks