Re: [PATCH 3/9] udf_rename(): only access the child content on cross-directory rename

From: Jan Kara
Date: Thu Nov 23 2023 - 23:21:05 EST


On Wed 22-11-23 19:36:46, Al Viro wrote:
> We can't really afford locking the source on same-directory rename;
> currently vfs_rename() tries to do that, but it will have to be
> changed. The logics in udf_rename() is lazy and goes looking for
> ".." in source even in same-directory case. It's not hard to get
> rid of that, leaving that behaviour only for cross-directory case;
> that VFS can get locks safely (and will keep doing that after the
> coming changes).
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/udf/namei.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/udf/namei.c b/fs/udf/namei.c
> index 3508ac484da3..fac806a7a8d4 100644
> --- a/fs/udf/namei.c
> +++ b/fs/udf/namei.c
> @@ -766,7 +766,7 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
> struct inode *old_inode = d_inode(old_dentry);
> struct inode *new_inode = d_inode(new_dentry);
> struct udf_fileident_iter oiter, niter, diriter;
> - bool has_diriter = false;
> + bool has_diriter = false, is_dir = false;
> int retval;
> struct kernel_lb_addr tloc;
>
> @@ -789,6 +789,9 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
> if (!empty_dir(new_inode))
> goto out_oiter;
> }
> + is_dir = true;
> + }
> + if (is_dir && old_dir != new_dir) {
> retval = udf_fiiter_find_entry(old_inode, &dotdot_name,
> &diriter);
> if (retval == -ENOENT) {
> @@ -878,7 +881,9 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
> udf_dir_entry_len(&diriter.fi));
> udf_fiiter_write_fi(&diriter, NULL);
> udf_fiiter_release(&diriter);
> + }
>
> + if (is_dir) {
> inode_dec_link_count(old_dir);
> if (new_inode)
> inode_dec_link_count(new_inode);
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR