xfs
[Top] [All Lists]

Re: [PATCH 0/3] xfsdump: more projid32bit fixes

To: Eric Sandeen <sandeen@xxxxxxxxxx>
Subject: Re: [PATCH 0/3] xfsdump: more projid32bit fixes
From: Eric Sandeen <sandeen@xxxxxxxxxxx>
Date: Mon, 22 Oct 2012 15:11:31 -0500
Cc: xfs-oss <xfs@xxxxxxxxxxx>
In-reply-to: <50788C50.40600@xxxxxxxxxx>
References: <50788C50.40600@xxxxxxxxxx>
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:16.0) Gecko/20121010 Thunderbird/16.0.1
On 10/12/12 4:32 PM, Eric Sandeen wrote:
> I recently sent a patch for 32-bit project IDs for xfsdump, to properly
> restore the top 16 bits, which otherwise get lost.  This forced a new
> dump format version 4 (we were currently at 3).
> 
> One thing missing is that we should not restore a dump with 32-bit
> project IDs onto a filesystem w/o that format; the restore will fail
> to restore the top 16 bits (but otherwise it returns success; attribute
> setting failures are not fatal (!?))
> 
> Also, 32-bit project ID is a bit uncommon; bumping the format (and making
> older restore incompatible) is a bit draconian.
> 
> 3 patches here:
> 
> 1/3: extend fs info call to get fs flags as well
> 2/3: default back to V3 and go to V4 only if the projid32 flag is set
> 3/3: fail restore if the target XFS fs doesn't have projid32 set

I think I should self-NAK this patchset, after a bit more thought.

Because the PROJID32BIT feature flag isn't available via the GEOM
ioctl for almost every kernel in existence (it'll be in what, 3.8?),

2/3) we'll fall back to V3 even if projid32bit is actually in use, and/or
3/3) we'll refuse to restore perfectly valid V4 dumps with 32-bit
     projids to older kernels just because they don't report the feature.

I think this'd cause more confusion/trouble than it's worth, since we've
been lacking the GEOM flag for so long.

-Eric

> I have to say, I'm not super happy with this.  I have nagging fear
> of feature-flag-itis, and I'm not sure how extensible this is as newer
> versions may appear.  But anyway, here's a place to start.
> 
> (p.s. anybody have wkendall's new email?)  ;)
> 
> _______________________________________________
> xfs mailing list
> xfs@xxxxxxxxxxx
> http://oss.sgi.com/mailman/listinfo/xfs
> 

<Prev in Thread] Current Thread [Next in Thread>