Thoughts on TMPFS no longer being considered "highly experimental"

Kostik Belousov kostikbel at
Thu Jun 23 20:21:59 UTC 2011

On Thu, Jun 23, 2011 at 09:31:09AM -0700, David O'Brien wrote:
> Does anyone object to this patch?
> David Wolfskill and I have run TMPFS on a number of machines for two
> years with no problems.
> I may have missed something, but I'm not aware of any serious PRs on
> TMPFS either.
> Index: tmpfs_vfsops.c
> ===================================================================
> --- tmpfs_vfsops.c	(revision 221113)
> +++ tmpfs_vfsops.c	(working copy)
> @@ -155,9 +155,6 @@ tmpfs_mount(struct mount *mp)
>  		return EOPNOTSUPP;
>  	}
> -	printf("WARNING: TMPFS is considered to be a highly experimental "
> -	    "feature in FreeBSD.\n");
> -
>  	vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
>  	error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
>  	VOP_UNLOCK(mp->mnt_vnodecovered, 0);

The things I am aware of:
- there is a races on the lookup. They were papered over in r212305,
but the bug was not really fixed, AFAIR.

- the tmpfs does double-buffering for the mapped vnodes. This is quite
insulting for the memory-backed fs, isn't it ? I have a patch, but it is
still under review.

- I believe Peter Holm has more test cases that fails with tmpfs. He
would have more details. I somewhat remember some panic on execve(2) the
binary located on tmpfs.

Removing the warning will not make the issues coming away.
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