ext4: reserve codepoints used by the ext4 encryption feature

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/ext4.h

@@ -364,7 +364,8 @@ struct flex_groups {
 #define EXT4_DIRTY_FL			0x00000100
 #define EXT4_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
 #define EXT4_NOCOMPR_FL			0x00000400 /* Don't compress */
-#define EXT4_ECOMPR_FL			0x00000800 /* Compression error */
+	/* nb: was previously EXT2_ECOMPR_FL */
+#define EXT4_ENCRYPT_FL			0x00000800 /* encrypted file */
 /* End compression flags --- maybe not all used */
 #define EXT4_INDEX_FL			0x00001000 /* hash-indexed directory */
 #define EXT4_IMAGIC_FL			0x00002000 /* AFS directory */
@@ -421,7 +422,7 @@ enum {
 	EXT4_INODE_DIRTY	= 8,
 	EXT4_INODE_COMPRBLK	= 9,	/* One or more compressed clusters */
 	EXT4_INODE_NOCOMPR	= 10,	/* Don't compress */
-	EXT4_INODE_ECOMPR	= 11,	/* Compression error */
+	EXT4_INODE_ENCRYPT	= 11,	/* Compression error */
 /* End compression flags --- maybe not all used */
 	EXT4_INODE_INDEX	= 12,	/* hash-indexed directory */
 	EXT4_INODE_IMAGIC	= 13,	/* AFS directory */
@@ -466,7 +467,7 @@ static inline void ext4_check_flag_values(void)
 	CHECK_FLAG_VALUE(DIRTY);
 	CHECK_FLAG_VALUE(COMPRBLK);
 	CHECK_FLAG_VALUE(NOCOMPR);
-	CHECK_FLAG_VALUE(ECOMPR);
+	CHECK_FLAG_VALUE(ENCRYPT);
 	CHECK_FLAG_VALUE(INDEX);
 	CHECK_FLAG_VALUE(IMAGIC);
 	CHECK_FLAG_VALUE(JOURNAL_DATA);
@@ -1043,6 +1044,12 @@ extern void ext4_set_bits(void *bm, int cur, int len);
 /* Metadata checksum algorithm codes */
 #define EXT4_CRC32C_CHKSUM		1
 
+/* Encryption algorithms */
+#define EXT4_ENCRYPTION_MODE_INVALID		0
+#define EXT4_ENCRYPTION_MODE_AES_256_XTS	1
+#define EXT4_ENCRYPTION_MODE_AES_256_GCM	2
+#define EXT4_ENCRYPTION_MODE_AES_256_CBC	3
+
 /*
  * Structure of the super block
  */
@@ -1156,7 +1163,8 @@ struct ext4_super_block {
 	__le32	s_grp_quota_inum;	/* inode for tracking group quota */
 	__le32	s_overhead_clusters;	/* overhead blocks/clusters in fs */
 	__le32	s_backup_bgs[2];	/* groups with sparse_super2 SBs */
-	__le32	s_reserved[106];	/* Padding to the end of the block */
+	__u8	s_encrypt_algos[4];	/* Encryption algorithms in use  */
+	__le32	s_reserved[105];	/* Padding to the end of the block */
 	__le32	s_checksum;		/* crc32c(superblock) */
 };
 
@@ -1537,6 +1545,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
 #define EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM	0x2000 /* use crc32c for bg */
 #define EXT4_FEATURE_INCOMPAT_LARGEDIR		0x4000 /* >2GB or 3-lvl htree */
 #define EXT4_FEATURE_INCOMPAT_INLINE_DATA	0x8000 /* data in inode */
+#define EXT4_FEATURE_INCOMPAT_ENCRYPT		0x10000
 
 #define EXT2_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \