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From: Will Deacon <will.deacon@arm.com>
To: "G. Campana" <gcampana+kvm@quarkslab.com>
Cc: kvm@vger.kernel.org, andre.przywara@arm.com
Subject: Re: [PATCH 7/7] kvmtool: 9p: refactor rel_to_abs()
Date: Thu, 17 Nov 2016 12:20:08 +0000	[thread overview]
Message-ID: <20161117122008.GF22855@arm.com> (raw)
In-Reply-To: <9c821c8f-46a7-052c-0c0c-7c84cc19a8f6@quarkslab.com>

On Thu, Nov 10, 2016 at 04:18:54PM +0100, G. Campana wrote:
> On 08/11/2016 03:38, Will Deacon wrote:
> > On Tue, Oct 18, 2016 at 06:03:05PM +0200, G. Campana wrote:
> >> @@ -614,7 +618,6 @@ static void virtio_p9_readdir(struct p9_dev *p9dev,
> >>  	struct stat st;
> >>  	struct p9_fid *fid;
> >>  	struct dirent *dent;
> >> -	char full_path[PATH_MAX];
> >>  	u64 offset, old_offset;
> >>  
> >>  	rcount = 0;
> >> @@ -645,11 +648,8 @@ static void virtio_p9_readdir(struct p9_dev *p9dev,
> >>  			break;
> >>  		}
> >>  		old_offset = dent->d_off;
> >> -		if (rel_to_abs(p9dev, dent->d_name, full_path, sizeof(full_path)) != 0) {
> >> -			errno = ENAMETOOLONG;
> >> -			goto err_out;
> >> -		}
> >> -		lstat(full_path, &st);
> >> +		if (stat_rel(p9dev, dent->d_name, &st) != 0)
> >> +			memset(&st, -1, sizeof(st));
> > 
> > Why the memset, and not goto err_out?
> > 
> Because the user may not be allowed to stat some entries in a directory
> and it shouldn't make readdir() fail.

Ok, but is memsetting to -1 really the right thing to do? This gets
"converted" into a p9_qid_t, which will then look pretty strange (path
and version will be set to 0xff, type will be set to P9_QTDIR).

Does 9p not have a better way to communicate that the stat failed?

Will

  reply	other threads:[~2016-11-17 17:07 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-18 16:03 [PATCH 7/7] kvmtool: 9p: refactor rel_to_abs() G. Campana
2016-11-08  2:38 ` Will Deacon
2016-11-10 15:18   ` G. Campana
2016-11-17 12:20     ` Will Deacon [this message]
2016-11-18 15:33       ` G. Campana
2016-11-18 15:37         ` Will Deacon

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