[PATCH] Re: ENOATTR and other error enums

From: Nathan Scott (nathans@sgi.com)
Date: Tue Oct 09 2001 - 00:01:14 EST


hi fellas,

Here is an errno.h patch which provides these new errno values.
XFS needs both values. ENOATTR is also required by the ext2
extended attributes project (and any other filesystem intending
to implement extended attributes in the future). Both values
need to be visible in both kernel and user space, so this patch
would be an initial step toward libc support also, hopefully.

In the absence of any cleaner way to do this (?), could we have
this patch applied please? Any/all feedback much appreciated
-- thanks.

cheers.

On Mon, Oct 08, 2001 at 12:22:02PM +1100, Nathan Scott wrote:
> hi there,
>
> On Sat, Oct 06, 2001 at 04:24:40PM +1000, monkeyiq wrote:
> > Hi,
> > Anyone know where these are defined in Linux? I dont seem
> > to be able to find them, even with find/grep in /usr/include.
>
> ENOATTR is not a blessed errno in Linux. In XFS we have simply
> defined it to be the same as ENODATA for the time being. The
> ext2 extended attributes project define it to be EDOM, also as
> a stop-gap solution I imagine.
>
> A similar problem exists with ENOTSUP (defined by POSIX 1003.1b?)
> - this is only supported via linux/asm-parisc/errno.h as a real
> errno, among all the architectures. Both the XFS and ext2 extended
> attributes implementations define this errno to be EOPNOTSUPP as an
> interim solution. Ah, wait - from a quick test, glibc does seem to
> do exactly this also, so this one is not a problem (except perhaps
> on the parisc port? -- hmm, that could actually be a bug on parisc).
>
> On a related topic, but not specific to extended attributes - for
> XFS in general, we needed one other errno - EFSCORRUPTED. This is
> used when XFS goes into forced shutdown mode for a filesystem that
> has been detected as on-disk corrupt, to stop making the situation
> any worse (user must umount/xfs_repair). We couldn't find any pre-
> existing Linux errno vaguely similar to this one, so it was defined
> to "990" until a real solution could be found.
>
> Obviously, these are not the correct long-term solutions ... they
> need to become real Linux errno's, I think, and ENOTSUP could be
> defined to EOPNOTSUPP? - EWOULDBLOCK, EDEADLOCK seem to do this.
> I'm not sure how to reach that point though (CC'ing linux-kernel
> for any advice) - for reference, in IRIX these errnos are defined
> as follows:
>
> ENOATTR = Attribute not found
> EFSCORRUPTED = Filesystem is corrupted
>
> > Also, is there a function to get a string rep of the error
> > that occured in the attr code?
>
> Someday it should become a part of asm-XXXXX/errno.h (errno's are
> architecture specific) and the libc strerror(3) routine should be
> able to provide a meaningful string. But currently that does not
> happen.
>
> cheers.
>
> --
> Nathan

-- 
Nathan


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