ACL issue (Was Re: HEADS UP: ZFSv28 is in!)

[Steve Wills]

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On 03/06/11 10:37, Jeremy Chadwick wrote:
> 
> At first glance it looks like acl_set_fd_np(3) isn't working on an
> md-backed filesystem; specifically, it's returning EOPNOTSUPP.  You
> should be able to reproduce the problem by doing a setfacl on something
> in /tmp/foobar.
> 
> Looking through src/bin/cp/utils.c, this is the code:
> 
> 420         if (acl_set_fd_np(dest_fd, acl, acl_type) < 0) {
> 421                 warn("failed to set acl entries for %s", to.p_path);
> 422                 acl_free(acl);
> 423                 return (1);
> 424         }
> 
> EOPNOTSUPP for acl_set_fd_np(3) is defined as:
> 
>      [EOPNOTSUPP]       The file system does not support ACL retrieval.
> 
> This would be referring to the destination filesystem.
> 
> Looking through the md(4) source for references to EOPNOTSUPP, we do
> find some references:
> 
> $ egrep -n -r "EOPNOTSUPP|ENOTSUP" /usr/src/sys/dev/md
> /usr/src/sys/dev/md/md.c:423:           return (EOPNOTSUPP);
> /usr/src/sys/dev/md/md.c:475:                   error = EOPNOTSUPP;
> /usr/src/sys/dev/md/md.c:523:           return (EOPNOTSUPP);
> /usr/src/sys/dev/md/md.c:601:           return (EOPNOTSUPP);
> /usr/src/sys/dev/md/md.c:731:                           error = EOPNOTSUPP;
> 
> Line 423 is within mdstart_malloc(), and it returns EOPNOTSUPP on any
> BIO operation other than READ/WRITE/DELETE.  Line 475 is a continuation
> of that.
> 
> Line 508 is within mdstart_vnode(), behaving effectively the same as
> line 423.  Line 601 is within mdstart_swap(), behaving effectively the
> same as line 423.
> 
> Line 731 is within md_kthread(), and indicates only BIO operation
> BIO_GETATTR is supported.  This would not be an "ACL attribute" thing,
> but rather getting attributes of the backing device itself.  The code
> hints at that:
> 
>  722                 if (bp->bio_cmd == BIO_GETATTR) {
>  723                         if ((sc->fwsectors && sc->fwheads &&
>  724                             (g_handleattr_int(bp, "GEOM::fwsectors",
>  725                             sc->fwsectors) ||
>  726                             g_handleattr_int(bp, "GEOM::fwheads",
>  727                             sc->fwheads))) ||
>  728                             g_handleattr_int(bp, "GEOM::candelete", 1))
>  729                                 error = -1;
>  730                         else
>  731                                 error = EOPNOTSUPP;
>  732                 } else {

Thanks for the investigation! So this seems to be a bug in md? That's
too bad, I was enjoying using it to make my tinderbox builds faster.

> This leaves me with some ideas; just tossing them out here...
> 
> 1. Maybe/somehow this is caused by swap being used as the backing
>    type/store for md(4)?  Try using "mdconfig -t malloc -o reserve"
>    instead, temporarily anyway.

Seems to be the same.

> 2. Are you absolutely 100% sure the kernel you're using was built
>    with "options UFS_ACL" defined in it?  Doing a "strings -a
>    /boot/kernel/kernel | grep UFS_ACL" should suffice.
> 

Yep, it does:

% strings -a /boot/kernel/kernel | grep UFS_ACL
options UFS_ACL

(My kernel config is just "include GENERIC" then a bunch of "nooptions"
for KDB, DDB, GDB, INVARIANTS, WITNESS, etc.)

Steve
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