Re: [RFC][PATCH 00/12] Enhanced file stat system call

From: J. Bruce Fields
Date: Wed Nov 25 2015 - 12:52:08 EST


On Fri, Nov 20, 2015 at 04:28:35PM +0000, David Howells wrote:
> Martin Steigerwald <martin@xxxxxxxxxxxx> wrote:
>
> > Any plans to add limitations of filesystem to the call like maximum file
> > size? I know its mostly relevant for just for FAT32, but on any account
> > rather than trying to write 4 GiB and then file, it would be good to at some
> > time get a dialog at the beginning of the copy.
>
> Adding filesystem limits can be done. I got a shopping list of things people
> wanted a while back and I've worked off of that list. I can add other things
> - that's on of the reasons I left room for expansion.

I ran across systemd/src/basic/path-util.c:fd_is_mount_point() the other
day, and the contortions it goes through made me wonder if we should
also add mnt_id and/or an is_mountpoint boolean--it's annoying to have
to do name_to_handle_at() (not supported on all filesystems) just to get
mnt_id.

(Looking at it now I see it falls back on reading mount id from
/proc/self/fdinfo/<fd>. Maybe that's good enough. May depend on
whether there's a potential user that doesn't want to assume access to
/proc?)

--b.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/