On Tue, 2018-07-31 at 14:10 -0700, Mark Fasheh 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@xxxxxxx>
> ---
> 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);
This code is under a spinlock (blocked_locks_lock or ctx->flc_lock). I
don't think it'll be ok to call ->getattr while holding a spinlock.
> /* 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);
> } else {
> seq_printf(f, "%d <none>:0 ", fl_pid);
> }
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
