diff --git a/fs/inode.c b/fs/inode.c
index f7c8c0fe11d4..2995130e0cdc 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2100,10 +2100,8 @@ void inode_init_owner(struct inode *inode, const struct inode *dir,
 		/* Directories are special, and always inherit S_ISGID */
 		if (S_ISDIR(mode))
 			mode |= S_ISGID;
-		else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) &&
-			 !in_group_p(inode->i_gid) &&
-			 !capable_wrt_inode_uidgid(dir, CAP_FSETID))
-			mode &= ~S_ISGID;
+		else
+			mode = mode_strip_sgid(dir, mode);
 	} else
 		inode->i_gid = current_fsgid();
 	inode->i_mode = mode;
@@ -2359,3 +2357,31 @@ int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
 	return 0;
 }
 EXPORT_SYMBOL(vfs_ioc_fssetxattr_check);
+
+/**
+ * mode_strip_sgid - handle the sgid bit for non-directories
+ * @dir: parent directory inode
+ * @mode: mode of the file to be created in @dir
+ *
+ * If the @mode of the new file has both the S_ISGID and S_IXGRP bit
+ * raised and @dir has the S_ISGID bit raised ensure that the caller is
+ * either in the group of the parent directory or they have CAP_FSETID
+ * in their user namespace and are privileged over the parent directory.
+ * In all other cases, strip the S_ISGID bit from @mode.
+ *
+ * Return: the new mode to use for the file
+ */
+umode_t mode_strip_sgid(const struct inode *dir, umode_t mode)
+{
+	if ((mode & (S_ISGID | S_IXGRP)) != (S_ISGID | S_IXGRP))
+		return mode;
+	if (S_ISDIR(mode) || !dir || !(dir->i_mode & S_ISGID))
+		return mode;
+	if (in_group_p(dir->i_gid))
+		return mode;
+	if (capable_wrt_inode_uidgid(dir, CAP_FSETID))
+		return mode;
+
+	return mode & ~S_ISGID;
+}
+EXPORT_SYMBOL(mode_strip_sgid);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fbbd7ef7f653..d9b97ccd65e5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1743,6 +1743,7 @@ extern long compat_ptr_ioctl(struct file *file, unsigned int cmd,
 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
 			umode_t mode);
 extern bool may_open_dev(const struct path *path);
+umode_t mode_strip_sgid(const struct inode *dir, umode_t mode);
 /*
  * VFS FS_IOC_FIEMAP helper definitions.
  */