Re: [PATCH v7 7/9] fscrypt: add inline encryption support

[Eric Biggers <ebiggers@kernel.org>]

On Fri, Feb 21, 2020 at 03:50:48AM -0800, Satya Tangirala wrote:
> +/**
> + * fscrypt_inode_uses_inline_crypto - test whether an inode uses inline
> + *				      encryption
> + * @inode: an inode
> + *
> + * Return: true if the inode requires file contents encryption and if the
> + *	   encryption should be done in the block layer via blk-crypto rather
> + *	   than in the filesystem layer.
> + */
> +bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
> +{
> +	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
> +		inode->i_crypt_info->ci_inlinecrypt;
> +}
> +EXPORT_SYMBOL_GPL(fscrypt_inode_uses_inline_crypto);
> +
> +/**
> + * fscrypt_inode_uses_fs_layer_crypto - test whether an inode uses fs-layer
> + *					encryption
> + * @inode: an inode
> + *
> + * Return: true if the inode requires file contents encryption and if the
> + *	   encryption should be done in the filesystem layer rather than in the
> + *	   block layer via blk-crypto.
> + */
> +bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
> +{
> +	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
> +		!inode->i_crypt_info->ci_inlinecrypt;
> +}
> +EXPORT_SYMBOL_GPL(fscrypt_inode_uses_fs_layer_crypto);

We should use the fscrypt_needs_contents_encryption() helper function which I
added in v5.6.  I.e.:

diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index 72692366795aa9..36510802a3665a 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -32,7 +32,7 @@ void fscrypt_select_encryption_impl(struct fscrypt_info *ci)
 	struct super_block *sb = inode->i_sb;
 
 	/* The file must need contents encryption, not filenames encryption */
-	if (!S_ISREG(inode->i_mode))
+	if (!fscrypt_needs_contents_encryption(inode))
 		return;
 
 	/* blk-crypto must implement the needed encryption algorithm */
@@ -148,7 +148,7 @@ void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key)
  */
 bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
 {
-	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
+	return fscrypt_needs_contents_encryption(inode) &&
 		inode->i_crypt_info->ci_inlinecrypt;
 }
 EXPORT_SYMBOL_GPL(fscrypt_inode_uses_inline_crypto);
@@ -164,7 +164,7 @@ EXPORT_SYMBOL_GPL(fscrypt_inode_uses_inline_crypto);
  */
 bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
 {
-	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
+	return fscrypt_needs_contents_encryption(inode) &&
 		!inode->i_crypt_info->ci_inlinecrypt;
 }
 EXPORT_SYMBOL_GPL(fscrypt_inode_uses_fs_layer_crypto);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 2a84131ab270fd..1d9810eb88b113 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -528,7 +528,7 @@ static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
 
 static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
 {
-	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
+	return fscrypt_needs_contents_encryption(inode);
 }
 
 static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio,