[RFC][PATCH 00/12] Enhanced file stat system call
dhowells at redhat.com
Thu Nov 26 15:19:43 UTC 2015
Christoph Hellwig <hch at infradead.org> wrote:
> from a quick look the statx bits looks fine in general. I think Ted
> last time had a problem with the IOC flag allocation, so you might
> want to ping him.
Yeah - he commented on that.
> But fsinfo with the multiplexer and the void pointer is just horrible.
> What were you thinking there?
I think the fsinfo data struct probably wants splitting up. Now this could be
done in a number of ways, including:
(1) By adding multiple syscalls (statfsx, fsinfo, netfsinfo, ...) but each
one needs a bit in the kernel to handle the basics (path/fd lookup,
security check, buffer allocation and freeing, ...) which could all be in
common - hence the mux method.
(2) Adding an argument to the fsinfo syscall since it has at least one
syscall argument spare.
(3) Offloading some of the bits to standardised xattr calls. The large
string fields (domain name, volume name, ...) would seem to be obvious
candidates for this.
Given that the core VFS gets to manage the contents of the buffer, it
shouldn't be as controversial as pioctl().
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