Re: [PATCH 4/4] locks: map correct ino/dev pairs when exporting to userspace

[Amir Goldstein <amir73il@gmail.com>]

On Wed, Aug 1, 2018 at 12:10 AM, Mark Fasheh <mfasheh@suse.de> wrote:
> /proc/locks does not always print the correct inode number/device pair.
> Update lock_get_status() to use vfs_map_unique_ino_dev() to get the real,
> unique values for userspace.
>
> Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> ---
>  fs/locks.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index db7b6917d9c5..3a012df87fd8 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2621,6 +2621,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>                             loff_t id, char *pfx)
>  {
>         struct inode *inode = NULL;
> +       struct dentry *dentry;
>         unsigned int fl_pid;
>         struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
>
> @@ -2633,8 +2634,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>         if (fl_pid == 0)
>                 return;
>
> -       if (fl->fl_file != NULL)
> +       if (fl->fl_file != NULL) {
>                 inode = locks_inode(fl->fl_file);
> +               dentry = file_dentry(fl->fl_file);
> +       }
>
>         seq_printf(f, "%lld:%s ", id, pfx);
>         if (IS_POSIX(fl)) {
> @@ -2681,10 +2684,13 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>                                : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
>         }
>         if (inode) {
> +               __u64 ino;
> +               dev_t dev;
> +
> +               vfs_map_unique_ino_dev(dentry, &ino, &dev);
>                 /* userspace relies on this representation of dev_t */
>                 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
> -                               MAJOR(inode->i_sb->s_dev),
> -                               MINOR(inode->i_sb->s_dev), inode->i_ino);
> +                               MAJOR(dev), MINOR(dev), inode->i_ino);

Don't you mean ,ino); ?

Thanks,
Amir.