[PATCH 1/2] fs: make do_mkdirat() take struct filename

[Dmitry Kadashev <dkadashev@gmail.com>]

Pass in the struct filename pointers instead of the user string, and
update the three callers to do the same. This is heavily based on
commit dbea8d345177 ("fs: make do_renameat2() take struct filename").

This behaves like do_unlinkat() and do_renameat2().

Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
---
 fs/internal.h |  1 +
 fs/namei.c    | 20 ++++++++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 6fd14ea213c3..23b8b427dbd2 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -80,6 +80,7 @@ long do_unlinkat(int dfd, struct filename *name);
 int may_linkat(struct path *link);
 int do_renameat2(int olddfd, struct filename *oldname, int newdfd,
 		 struct filename *newname, unsigned int flags);
+long do_mkdirat(int dfd, struct filename *name, umode_t mode);
 
 /*
  * namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index 03d0e11e4f36..9d26a51f3f54 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3654,17 +3654,23 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 }
 EXPORT_SYMBOL(vfs_mkdir);
 
-static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
+long do_mkdirat(int dfd, struct filename *name, umode_t mode)
 {
 	struct dentry *dentry;
 	struct path path;
 	int error;
 	unsigned int lookup_flags = LOOKUP_DIRECTORY;
 
+	if (IS_ERR(name))
+		return PTR_ERR(name);
+
 retry:
-	dentry = user_path_create(dfd, pathname, &path, lookup_flags);
-	if (IS_ERR(dentry))
-		return PTR_ERR(dentry);
+	name->refcnt++; /* filename_create() drops our ref */
+	dentry = filename_create(dfd, name, &path, lookup_flags);
+	if (IS_ERR(dentry)) {
+		error = PTR_ERR(dentry);
+		goto out;
+	}
 
 	if (!IS_POSIXACL(path.dentry->d_inode))
 		mode &= ~current_umask();
@@ -3676,17 +3682,19 @@ static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
+out:
+	putname(name);
 	return error;
 }
 
 SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
 {
-	return do_mkdirat(dfd, pathname, mode);
+	return do_mkdirat(dfd, getname(pathname), mode);
 }
 
 SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
 {
-	return do_mkdirat(AT_FDCWD, pathname, mode);
+	return do_mkdirat(AT_FDCWD, getname(pathname), mode);
 }
 
 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
-- 
2.28.0