[RFC PATCH v11 24/51] ceph: add ceph_encode_encrypted_dname() helper

[Jeff Layton <jlayton@xxxxxxxxxx>]

From: Xiubo Li <xiubli@xxxxxxxxxx>

Add a new helper that basically calls ceph_encode_encrypted_fname, but
with a qstr pointer instead of a dentry pointer. This will make it
simpler to decrypt names in a readdir reply, before we have a dentry.

Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/ceph/crypto.c | 11 ++++++++---
 fs/ceph/crypto.h |  8 ++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index e56017d66354..420a2cc1a8e5 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -128,7 +128,7 @@ void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req, struct ceph_acl_se
 	swap(req->r_fscrypt_auth, as->fscrypt_auth);
 }
 
-int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf)
+int ceph_encode_encrypted_dname(const struct inode *parent, struct qstr *d_name, char *buf)
 {
 	u32 len;
 	int elen;
@@ -143,7 +143,7 @@ int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentr
 	 *
 	 * See: fscrypt_setup_filename
 	 */
-	if (!fscrypt_fname_encrypted_size(parent, dentry->d_name.len, NAME_MAX, &len))
+	if (!fscrypt_fname_encrypted_size(parent, d_name->len, NAME_MAX, &len))
 		return -ENAMETOOLONG;
 
 	/* Allocate a buffer appropriate to hold the result */
@@ -151,7 +151,7 @@ int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentr
 	if (!cryptbuf)
 		return -ENOMEM;
 
-	ret = fscrypt_fname_encrypt(parent, &dentry->d_name, cryptbuf, len);
+	ret = fscrypt_fname_encrypt(parent, d_name, cryptbuf, len);
 	if (ret) {
 		kfree(cryptbuf);
 		return ret;
@@ -175,6 +175,11 @@ int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentr
 	return elen;
 }
 
+int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf)
+{
+	return ceph_encode_encrypted_dname(parent, &dentry->d_name, buf);
+}
+
 /**
  * ceph_fname_to_usr - convert a filename for userland presentation
  * @fname: ceph_fname to be converted
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index 7e56aded5124..e54150260eba 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -67,6 +67,7 @@ void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc);
 int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
 				 struct ceph_acl_sec_ctx *as);
 void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req, struct ceph_acl_sec_ctx *as);
+int ceph_encode_encrypted_dname(const struct inode *parent, struct qstr *d_name, char *buf);
 int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf);
 
 static inline int ceph_fname_alloc_buffer(struct inode *parent, struct fscrypt_str *fname)
@@ -108,6 +109,13 @@ static inline void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
 {
 }
 
+static inline int ceph_encode_encrypted_dname(const struct inode *parent,
+					      struct qstr *d_name, char *buf)
+{
+	memcpy(buf, d_name->name, d_name->len);
+	return d_name->len;
+}
+
 static inline int ceph_encode_encrypted_fname(const struct inode *parent,
 						struct dentry *dentry, char *buf)
 {
-- 
2.35.1