fscrypt: split supp and notsupp declarations into their own headers

Previously, each filesystem configured without encryption support would
define all the public fscrypt functions to their notsupp_* stubs.  This
list of #defines had to be updated in every filesystem whenever a change
was made to the public fscrypt functions.  To make things more
maintainable now that we have three filesystems using fscrypt, split the
old header fscrypto.h into several new headers.  fscrypt_supp.h contains
the real declarations and is included by filesystems when configured
with encryption support, whereas fscrypt_notsupp.h contains the inline
stubs and is included by filesystems when configured without encryption
support.  fscrypt_common.h contains common declarations needed by both.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 168 insertions, 0 deletions

diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h
new file mode 100644
index 000000000000..3511ca798804
--- /dev/null
+++ b/include/linux/fscrypt_notsupp.h
@@ -0,0 +1,168 @@
+/*
+ * fscrypt_notsupp.h
+ *
+ * This stubs out the fscrypt functions for filesystems configured without
+ * encryption support.
+ */
+
+#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)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
+{
+	return;
+}
+
+static inline struct page *fscrypt_encrypt_page(const struct inode *inode,
+						struct page *page,
+						unsigned int len,
+						unsigned int offs,
+						u64 lblk_num, gfp_t gfp_flags)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline int fscrypt_decrypt_page(const struct inode *inode,
+				       struct page *page,
+				       unsigned int len, unsigned int offs,
+				       u64 lblk_num)
+{
+	return -EOPNOTSUPP;
+}
+
+
+static inline void fscrypt_restore_control_page(struct page *page)
+{
+	return;
+}
+
+static inline void fscrypt_set_d_op(struct dentry *dentry)
+{
+	return;
+}
+
+static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry)
+{
+	return;
+}
+
+/* policy.c */
+static inline int fscrypt_ioctl_set_policy(struct file *filp,
+					   const void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_has_permitted_context(struct inode *parent,
+						struct inode *child)
+{
+	return 0;
+}
+
+static inline int fscrypt_inherit_context(struct inode *parent,
+					  struct inode *child,
+					  void *fs_data, bool preload)
+{
+	return -EOPNOTSUPP;
+}
+
+/* keyinfo.c */
+static inline int fscrypt_get_encryption_info(struct inode *inode)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void fscrypt_put_encryption_info(struct inode *inode,
+					       struct fscrypt_info *ci)
+{
+	return;
+}
+
+ /* fname.c */
+static inline int fscrypt_setup_filename(struct inode *dir,
+					 const struct qstr *iname,
+					 int lookup, struct fscrypt_name *fname)
+{
+	if (dir->i_sb->s_cop->is_encrypted(dir))
+		return -EOPNOTSUPP;
+
+	memset(fname, 0, sizeof(struct fscrypt_name));
+	fname->usr_fname = iname;
+	fname->disk_name.name = (unsigned char *)iname->name;
+	fname->disk_name.len = iname->len;
+	return 0;
+}
+
+static inline void fscrypt_free_filename(struct fscrypt_name *fname)
+{
+	return;
+}
+
+static inline u32 fscrypt_fname_encrypted_size(const struct inode *inode,
+					       u32 ilen)
+{
+	/* never happens */
+	WARN_ON(1);
+	return 0;
+}
+
+static inline int fscrypt_fname_alloc_buffer(const struct inode *inode,
+					     u32 ilen,
+					     struct fscrypt_str *crypto_str)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
+{
+	return;
+}
+
+static inline int fscrypt_fname_disk_to_usr(struct inode *inode,
+					    u32 hash, u32 minor_hash,
+					    const struct fscrypt_str *iname,
+					    struct fscrypt_str *oname)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_fname_usr_to_disk(struct inode *inode,
+					    const struct qstr *iname,
+					    struct fscrypt_str *oname)
+{
+	return -EOPNOTSUPP;
+}
+
+/* bio.c */
+static inline void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx,
+					     struct bio *bio)
+{
+	return;
+}
+
+static inline void fscrypt_pullback_bio_page(struct page **page, bool restore)
+{
+	return;
+}
+
+static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
+					sector_t pblk, unsigned int len)
+{
+	return -EOPNOTSUPP;
+}
+
+#endif	/* _LINUX_FSCRYPT_NOTSUPP_H */