ext4 crypto: add encryption policy and password salt support

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ildar Muslukhov <muslukhovi@gmail.com>

fs/ext4/ext4.h

@@ -589,6 +589,8 @@ enum {
 #define EXT4_ENCRYPTION_MODE_AES_256_CBC	3
 #define EXT4_ENCRYPTION_MODE_AES_256_CTS	4
 
+#include "ext4_crypto.h"
+
 /*
  * ioctl commands
  */
@@ -610,6 +612,9 @@ enum {
 #define EXT4_IOC_RESIZE_FS		_IOW('f', 16, __u64)
 #define EXT4_IOC_SWAP_BOOT		_IO('f', 17)
 #define EXT4_IOC_PRECACHE_EXTENTS	_IO('f', 18)
+#define EXT4_IOC_SET_ENCRYPTION_POLICY	_IOR('f', 19, struct ext4_encryption_policy)
+#define EXT4_IOC_GET_ENCRYPTION_PWSALT	_IOW('f', 20, __u8[16])
+#define EXT4_IOC_GET_ENCRYPTION_POLICY	_IOW('f', 21, struct ext4_encryption_policy)
 
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 /*
@@ -2011,6 +2016,16 @@ extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
 					      struct ext4_group_desc *gdp);
 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
 
+/* crypto_policy.c */
+int ext4_is_child_context_consistent_with_parent(struct inode *parent,
+						 struct inode *child);
+int ext4_inherit_context(struct inode *parent, struct inode *child);
+void ext4_to_hex(char *dst, char *src, size_t src_size);
+int ext4_process_policy(const struct ext4_encryption_policy *policy,
+			struct inode *inode);
+int ext4_get_policy(struct inode *inode,
+		    struct ext4_encryption_policy *policy);
+
 /* dir.c */
 extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
 				  struct file *,