Re: [PATCH 5/9] replace do_setxattr() with saner helpers.

[Al Viro <viro@zeniv.linux.org.uk>]

On Mon, Oct 07, 2024 at 12:20:20PM -0600, Jens Axboe wrote:
> On 10/7/24 12:09 PM, Jens Axboe wrote:
> >>>> Questions on the io_uring side:
> >>>> 	* you usually reject REQ_F_FIXED_FILE for ...at() at ->prep() time.
> >>>> Fine, but... what's the point of doing that in IORING_OP_FGETXATTR case?
> >>>> Or IORING_OP_GETXATTR, for that matter, since you pass AT_FDCWD anyway...
> >>>> Am I missing something subtle here?
> >>>
> >>> Right, it could be allowed for fgetxattr on the io_uring side. Anything
> >>> that passes in a struct file would be fair game to enable it on.
> >>> Anything that passes in a path (eg a non-fd value), it obviously
> >>> wouldn't make sense anyway.
> >>
> >> OK, done and force-pushed into #work.xattr.
> > 
> > I just checked, and while I think this is fine to do for the 'fd' taking
> > {s,g}etxattr, I don't think the path taking ones should allow
> > IOSQE_FIXED_FILE being set. It's nonsensical, as they don't take a file
> > descriptor. So I'd prefer if we kept it to just the f* variants. I can
> > just make this tweak in my io_uring 6.12 branch and get it upstream this
> > week, that'll take it out of your hands.
> > 
> > What do you think?
> 
> Like the below. You can update yours if you want, or I can shove this
> into 6.12, whatever is the easiest for you.

Can I put your s-o-b on that, with e.g.

io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE

Rejection of IOSQE_FIXED_FILE combined with IORING_OP_[GS]ETXATTR
is fine - these do not take a file descriptor, so such combination
makes no sense.  The checks are misplaced, though - as it is, they
triggers on IORING_OP_F[GS]ETXATTR as well, and those do take 
a file reference, no matter the origin. 

as commit message?