From: Sebastien Marie <semarie@kapouay.eu.org>
Subject: Re: Unlock fstat(2)
To: Martin Pieuchot <mpi@grenadille.net>, tech@openbsd.org
Date: Sun, 05 Jan 2025 11:52:48 +0100

Martin Pieuchot <mpi@grenadille.net> writes:

> sys_fstat() is implemented as a wrapper around `fo_stat'.  All
> implementations are ready to be called without KERNEL_LOCK() except
> for vn_statfile() below.
>
> This was part of my previous VFS unlock diff.
>
> ok?

ok semarie@

> Index: kern/syscalls.master
> ===================================================================
> RCS file: /cvs/src/sys/kern/syscalls.master,v
> diff -u -p -r1.265 syscalls.master
> --- kern/syscalls.master	2 Aug 2024 14:34:45 -0000	1.265
> +++ kern/syscalls.master	5 Jan 2025 10:02:35 -0000
> @@ -133,7 +133,7 @@
>  51	UNIMPL		acct
>  #endif
>  52	STD		{ int sys_sigpending(void); }
> -53	STD		{ int sys_fstat(int fd, struct stat *sb); }
> +53	STD NOLOCK	{ int sys_fstat(int fd, struct stat *sb); }
>  54	STD NOLOCK	{ int sys_ioctl(int fd, \
>  			    u_long com, ... void *data); }
>  55	STD		{ int sys_reboot(int opt); }
> Index: kern/vfs_vnops.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/vfs_vnops.c,v
> diff -u -p -r1.124 vfs_vnops.c
> --- kern/vfs_vnops.c	30 Dec 2024 02:46:00 -0000	1.124
> +++ kern/vfs_vnops.c	5 Jan 2025 10:03:02 -0000
> @@ -427,7 +427,13 @@ int
>  vn_statfile(struct file *fp, struct stat *sb, struct proc *p)
>  {
>  	struct vnode *vp = fp->f_data;
> -	return vn_stat(vp, sb, p);
> +	int error;
> +
> +	KERNEL_LOCK();
> +	error = vn_stat(vp, sb, p);
> +	KERNEL_UNLOCK();
> +
> +	return (error);
>  }
>  
>  /*
>
>

-- 
Sebastien Marie