f2fs crypto: add f2fs encryption facilities

Most of parts were copied from ext4, except:

 - add f2fs_restore_and_release_control_page which returns control page and
   restore control page
 - remove ext4_encrypted_zeroout()
 - remove sbi->s_file_encryption_mode & sbi->s_dir_encryption_mode
 - add f2fs_end_io_crypto_work for mpage_end_io
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/Makefile

@@ -6,4 +6,4 @@ f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
 f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
 f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
 f2fs-$(CONFIG_F2FS_IO_TRACE) += trace.o
-f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o
+f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o crypto.o

fs/f2fs/f2fs.h

@@ -1962,4 +1962,29 @@ int f2fs_is_child_context_consistent_with_parent(struct inode *,
 int f2fs_inherit_context(struct inode *, struct inode *, struct page *);
 int f2fs_process_policy(const struct f2fs_encryption_policy *, struct inode *);
 int f2fs_get_policy(struct inode *, struct f2fs_encryption_policy *);
+
+/* crypt.c */
+extern struct workqueue_struct *f2fs_read_workqueue;
+bool f2fs_valid_contents_enc_mode(uint32_t);
+uint32_t f2fs_validate_encryption_key_size(uint32_t, uint32_t);
+struct f2fs_crypto_ctx *f2fs_get_crypto_ctx(struct inode *);
+void f2fs_release_crypto_ctx(struct f2fs_crypto_ctx *);
+struct page *f2fs_encrypt(struct inode *, struct page *);
+int f2fs_decrypt(struct f2fs_crypto_ctx *, struct page *);
+int f2fs_decrypt_one(struct inode *, struct page *);
+void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx *, struct bio *);
+
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+void f2fs_restore_and_release_control_page(struct page **);
+void f2fs_restore_control_page(struct page *);
+
+int f2fs_init_crypto(void);
+void f2fs_exit_crypto(void);
+#else
+static inline void f2fs_restore_and_release_control_page(struct page **p) { }
+static inline void f2fs_restore_control_page(struct page *p) { }
+
+static inline int f2fs_init_crypto(void) { return 0; }
+static inline void f2fs_exit_crypto(void) { }
+#endif
 #endif

fs/f2fs/super.c

@@ -416,6 +416,9 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
 	/* Will be used by directory only */
 	fi->i_dir_level = F2FS_SB(sb)->dir_level;
 
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+	fi->i_crypt_info = NULL;
+#endif
 	return &fi->vfs_inode;
 }