ovl: Switch to generic_getxattr

Now that overlayfs has xattr handlers for iop->{set,remove}xattr, use
those same handlers for iop->getxattr as well.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/dir.c

@@ -1004,7 +1004,7 @@ const struct inode_operations ovl_dir_inode_operations = {
 	.permission	= ovl_permission,
 	.getattr	= ovl_dir_getattr,
 	.setxattr	= generic_setxattr,
-	.getxattr	= ovl_getxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= ovl_listxattr,
 	.removexattr	= generic_removexattr,
 	.get_acl	= ovl_get_acl,

fs/overlayfs/inode.c

@@ -238,16 +238,13 @@ int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
 	return err;
 }
 
-ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
-		     const char *name, void *value, size_t size)
+int ovl_xattr_get(struct dentry *dentry, const char *name,
+		  void *value, size_t size)
 {
 	struct dentry *realdentry = ovl_dentry_real(dentry);
 	ssize_t res;
 	const struct cred *old_cred;
 
-	if (ovl_is_private_xattr(name))
-		return -ENODATA;
-
 	old_cred = ovl_override_creds(dentry->d_sb);
 	res = vfs_getxattr(realdentry, name, value, size);
 	revert_creds(old_cred);
@@ -368,7 +365,7 @@ static const struct inode_operations ovl_file_inode_operations = {
 	.permission	= ovl_permission,
 	.getattr	= ovl_getattr,
 	.setxattr	= generic_setxattr,
-	.getxattr	= ovl_getxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= ovl_listxattr,
 	.removexattr	= generic_removexattr,
 	.get_acl	= ovl_get_acl,
@@ -381,7 +378,7 @@ static const struct inode_operations ovl_symlink_inode_operations = {
 	.readlink	= ovl_readlink,
 	.getattr	= ovl_getattr,
 	.setxattr	= generic_setxattr,
-	.getxattr	= ovl_getxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= ovl_listxattr,
 	.removexattr	= generic_removexattr,
 	.update_time	= ovl_update_time,

fs/overlayfs/overlayfs.h

@@ -187,8 +187,8 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 int ovl_permission(struct inode *inode, int mask);
 int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
 		  size_t size, int flags);
-ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
-		     const char *name, void *value, size_t size);
+int ovl_xattr_get(struct dentry *dentry, const char *name,
+		  void *value, size_t size);
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);

fs/overlayfs/super.c

@@ -986,6 +986,14 @@ static unsigned int ovl_split_lowerdirs(char *str)
 	return ctr;
 }
 
+static int __maybe_unused
+ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
+			struct dentry *dentry, struct inode *inode,
+			const char *name, void *buffer, size_t size)
+{
+	return ovl_xattr_get(dentry, handler->name, buffer, size);
+}
+
 static int __maybe_unused
 ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 			struct dentry *dentry, struct inode *inode,
@@ -1029,6 +1037,13 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 	return err;
 }
 
+static int ovl_own_xattr_get(const struct xattr_handler *handler,
+			     struct dentry *dentry, struct inode *inode,
+			     const char *name, void *buffer, size_t size)
+{
+	return -EPERM;
+}
+
 static int ovl_own_xattr_set(const struct xattr_handler *handler,
 			     struct dentry *dentry, struct inode *inode,
 			     const char *name, const void *value,
@@ -1037,6 +1052,13 @@ static int ovl_own_xattr_set(const struct xattr_handler *handler,
 	return -EPERM;
 }
 
+static int ovl_other_xattr_get(const struct xattr_handler *handler,
+			       struct dentry *dentry, struct inode *inode,
+			       const char *name, void *buffer, size_t size)
+{
+	return ovl_xattr_get(dentry, name, buffer, size);
+}
+
 static int ovl_other_xattr_set(const struct xattr_handler *handler,
 			       struct dentry *dentry, struct inode *inode,
 			       const char *name, const void *value,
@@ -1049,6 +1071,7 @@ static const struct xattr_handler __maybe_unused
 ovl_posix_acl_access_xattr_handler = {
 	.name = XATTR_NAME_POSIX_ACL_ACCESS,
 	.flags = ACL_TYPE_ACCESS,
+	.get = ovl_posix_acl_xattr_get,
 	.set = ovl_posix_acl_xattr_set,
 };
 
@@ -1056,16 +1079,19 @@ static const struct xattr_handler __maybe_unused
 ovl_posix_acl_default_xattr_handler = {
 	.name = XATTR_NAME_POSIX_ACL_DEFAULT,
 	.flags = ACL_TYPE_DEFAULT,
+	.get = ovl_posix_acl_xattr_get,
 	.set = ovl_posix_acl_xattr_set,
 };
 
 static const struct xattr_handler ovl_own_xattr_handler = {
 	.prefix	= OVL_XATTR_PREFIX,
+	.get = ovl_own_xattr_get,
 	.set = ovl_own_xattr_set,
 };
 
 static const struct xattr_handler ovl_other_xattr_handler = {
 	.prefix	= "", /* catch all */
+	.get = ovl_other_xattr_get,
 	.set = ovl_other_xattr_set,
 };