[PATCH v2 01/11] fscrypt: clean up include file mess

[Eric Biggers <ebiggers3@gmail.com>]

From: Dave Chinner <dchinner@redhat.com>

Filesystems have to include different header files based on whether they
are compiled with encryption support or not. That's nasty and messy.

Instead, rationalise the headers so we have a single include fscrypt.h
and let it decide what internal implementation to include based on the
__FS_HAS_ENCRYPTION define.  Filesystems set __FS_HAS_ENCRYPTION to 1
before including linux/fscrypt.h if they are built with encryption
support.  Otherwise, they must set __FS_HAS_ENCRYPTION to 0.

Add guards to prevent fscrypt_supp.h and fscrypt_notsupp.h from being
directly included by filesystems.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
[EB: use 1 and 0 rather than defined/undefined]
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/crypto/fscrypt_private.h                   |  3 +-
 fs/ext4/ext4.h                                |  8 ++----
 fs/f2fs/f2fs.h                                |  8 ++----
 fs/ubifs/ubifs.h                              |  9 +++---
 include/linux/{fscrypt_common.h => fscrypt.h} | 41 ++++++++++++++++++---------
 include/linux/fscrypt_notsupp.h               |  7 +++--
 include/linux/fscrypt_supp.h                  |  7 +++--
 7 files changed, 49 insertions(+), 34 deletions(-)
 rename include/linux/{fscrypt_common.h => fscrypt.h} (80%)

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index a1d5021c31ef..a180981ee6d7 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -11,7 +11,8 @@
 #ifndef _FSCRYPT_PRIVATE_H
 #define _FSCRYPT_PRIVATE_H
 
-#include <linux/fscrypt_supp.h>
+#define __FS_HAS_ENCRYPTION 1
+#include <linux/fscrypt.h>
 #include <crypto/hash.h>
 
 /* Encryption parameters */
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e2abe01c8c6b..ca6d6166b85c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -33,17 +33,15 @@
 #include <linux/percpu_counter.h>
 #include <linux/ratelimit.h>
 #include <crypto/hash.h>
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
 #include <linux/falloc.h>
 #include <linux/percpu-rwsem.h>
 #ifdef __KERNEL__
 #include <linux/compat.h>
 #endif
 
+#define __FS_HAS_ENCRYPTION IS_ENABLED(CONFIG_EXT4_FS_ENCRYPTION)
+#include <linux/fscrypt.h>
+
 /*
  * The fourth extended filesystem constants/structures
  */
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9a7c90386947..fc53aebaf3ae 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -23,13 +23,11 @@
 #include <linux/bio.h>
 #include <linux/blkdev.h>
 #include <linux/quotaops.h>
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
 #include <crypto/hash.h>
 
+#define __FS_HAS_ENCRYPTION IS_ENABLED(CONFIG_F2FS_FS_ENCRYPTION)
+#include <linux/fscrypt.h>
+
 #ifdef CONFIG_F2FS_CHECK_FS
 #define f2fs_bug_on(sbi, condition)	BUG_ON(condition)
 #else
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index cd43651f1731..6a346d4af98f 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -38,12 +38,11 @@
 #include <linux/backing-dev.h>
 #include <linux/security.h>
 #include <linux/xattr.h>
-#ifdef CONFIG_UBIFS_FS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
 #include <linux/random.h>
+
+#define __FS_HAS_ENCRYPTION IS_ENABLED(CONFIG_UBIFS_FS_ENCRYPTION)
+#include <linux/fscrypt.h>
+
 #include "ubifs-media.h"
 
 /* Version of this UBIFS implementation */
diff --git a/include/linux/fscrypt_common.h b/include/linux/fscrypt.h
similarity index 80%
rename from include/linux/fscrypt_common.h
rename to include/linux/fscrypt.h
index 97f738628b36..bfc962e62078 100644
--- a/include/linux/fscrypt_common.h
+++ b/include/linux/fscrypt.h
@@ -1,14 +1,17 @@
 /*
- * fscrypt_common.h: common declarations for per-file encryption
+ * fscrypt.h: declarations for per-file encryption
+ *
+ * Filesystems that implement per-file encryption include this header
+ * file with the __FS_HAS_ENCRYPTION set according to whether that filesystem
+ * is being built with encryption support or not.
  *
  * Copyright (C) 2015, Google, Inc.
  *
  * Written by Michael Halcrow, 2015.
  * Modified by Jaegeuk Kim, 2015.
  */
-
-#ifndef _LINUX_FSCRYPT_COMMON_H
-#define _LINUX_FSCRYPT_COMMON_H
+#ifndef _LINUX_FSCRYPT_H
+#define _LINUX_FSCRYPT_H
 
 #include <linux/key.h>
 #include <linux/fs.h>
@@ -119,23 +122,35 @@ static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
 	return false;
 }
 
+#if __FS_HAS_ENCRYPTION
+
 static inline struct page *fscrypt_control_page(struct page *page)
 {
-#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
 	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
-#else
+}
+
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+	return (inode->i_crypt_info != NULL);
+}
+
+#include <linux/fscrypt_supp.h>
+
+#else /* !__FS_HAS_ENCRYPTION */
+
+static inline struct page *fscrypt_control_page(struct page *page)
+{
 	WARN_ON_ONCE(1);
 	return ERR_PTR(-EINVAL);
-#endif
 }
 
-static inline int fscrypt_has_encryption_key(const struct inode *inode)
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
 {
-#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
-	return (inode->i_crypt_info != NULL);
-#else
 	return 0;
-#endif
 }
 
-#endif	/* _LINUX_FSCRYPT_COMMON_H */
+#include <linux/fscrypt_notsupp.h>
+#endif /* __FS_HAS_ENCRYPTION */
+
+
+#endif	/* _LINUX_FSCRYPT_H */
diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h
index ec406aed2f2f..2d0b6960831e 100644
--- a/include/linux/fscrypt_notsupp.h
+++ b/include/linux/fscrypt_notsupp.h
@@ -3,13 +3,16 @@
  *
  * This stubs out the fscrypt functions for filesystems configured without
  * encryption support.
+ *
+ * Do not include this file directly. Use fscrypt.h instead!
  */
+#ifndef _LINUX_FSCRYPT_H
+#error "Incorrect include of linux/fscrypt_notsupp.h!"
+#endif
 
 #ifndef _LINUX_FSCRYPT_NOTSUPP_H
 #define _LINUX_FSCRYPT_NOTSUPP_H
 
-#include <linux/fscrypt_common.h>
-
 /* crypto.c */
 static inline struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode,
 						  gfp_t gfp_flags)
diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h
index 32e2fcf13b01..5a90e5ef4687 100644
--- a/include/linux/fscrypt_supp.h
+++ b/include/linux/fscrypt_supp.h
@@ -1,14 +1,15 @@
 /*
  * fscrypt_supp.h
  *
- * This is included by filesystems configured with encryption support.
+ * Do not include this file directly. Use fscrypt.h instead!
  */
+#ifndef _LINUX_FSCRYPT_H
+#error "Incorrect include of linux/fscrypt_supp.h!"
+#endif
 
 #ifndef _LINUX_FSCRYPT_SUPP_H
 #define _LINUX_FSCRYPT_SUPP_H
 
-#include <linux/fscrypt_common.h>
-
 /* crypto.c */
 extern struct kmem_cache *fscrypt_info_cachep;
 extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
-- 
2.14.2.920.gcf0c67979c-goog