libfs: support RENAME_NOREPLACE in simple_rename()

This is trivial to do:

 - add flags argument to simple_rename()
 - check if flags doesn't have any other than RENAME_NOREPLACE
 - assign simple_rename() to .rename2 instead of .rename

Filesystems converted:

hugetlbfs, ramfs, bpf.

Debugfs uses simple_rename() to implement debugfs_rename(), which is for
debugfs instances to rename files internally, not for userspace filesystem
access.  For this case pass zero flags to simple_rename().

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 74dc8b9..4758353 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -349,11 +349,15 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry)
 EXPORT_SYMBOL(simple_rmdir);
 
 int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
-		struct inode *new_dir, struct dentry *new_dentry)
+		  struct inode *new_dir, struct dentry *new_dentry,
+		  unsigned int flags)
 {
 	struct inode *inode = d_inode(old_dentry);
 	int they_are_dirs = d_is_dir(old_dentry);
 
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
 	if (!simple_empty(new_dentry))
 		return -ENOTEMPTY;