Re: [PATCH] xfs_quota: print quota id number if the name can't be found

[Eric Sandeen <sandeen@redhat.com>]

On 4/6/16 12:39 PM, Zorro Lang wrote:
> When use GETNEXTQUOTA ioctl to report project quota, it always
> report an unexpected quota:
> 
>   (null) 0 0 0 00 [--------]
> 
> The ID 0 store the default quota, even if no one set default quota,
> it still have quota accounting, but not enforced. So GETNEXTQUOTA
> can find and report this undefined quota.
> 
> From this problem, I thought if others' quota name miss, (null) will
> be printed too. e.g.
> 
>   # xfs_quota -xc "limit -u bsoft=300m bhard=400m test" $mnt
>   # xfs_quota -xc "report -u" $mnt
>   User ID          Used       Soft       Hard    Warn/Grace
>   ---------- --------------------------------------------------
>   root                0          0          0     00 [--------]
>   test                0     307200     409600     00 [--------]
>   # userdel -r test
>   # xfs_quota -xc "report -u" $mnt
>   User ID          Used       Soft       Hard    Warn/Grace
>   ---------- --------------------------------------------------
>   root                0          0          0     00 [--------]
>   (null)              0     307200     409600     00 [--------]
> 
> So this problem same with above id 0's problem. For deal with this,
> this patch will print id number if the name can't be found.
> 
> But if use old GETQUOTA ioctl, it won't print project id 0 quota
> information(if it's not defined). That's different with GETNEXTQUOTA.
> For keep consistent, this patch also print project id 0 when use old
> GETQUOTA.
> 
> Signed-off-by: Zorro Lang <zlang@redhat.com>

Thanks, I think this makes sense; so this solves 2 problems.

1) always print the id # if there is no name mapping during quota report, and
2) always print default project quota information, even if no PRID 0 in in the projects map.

UID & GID always (?) have an ID 0 defined (if the system has no root user or group,
something is very odd, but it is normal to have no PRID 0 defined)

other comments below.

> ---
> 
> Hi,
> 
> This's a problem from GETNEXTQUOTA feature. The original disscussion
> is as below:
> 
> http://thread.gmane.org/gmane.comp.file-systems.fstests/1852/focus=1968
> 
> Then Eryu send a patch to xfstests, try to fix the test failure bring
> by this bug. The disscussion is as below:
> 
> http://oss.sgi.com/archives/xfs/2016-04/msg00002.html
> 
> Finally we decided to fix this problem in xfsprogs. After talked with
> Eric Sandeen, I wrote this patch. At first, Eric thought we shouldn't
> print project id 0 quota information, if no one set limit for it.
> 
> Then he change his mind to always print "root" as project id 0's name,
> if no one define a name for it. But there's another problem, if we
> print "root" for project id 0, but we can't run:
> 
>   xfs_quota -xc "limit -p xxx xxx root" $mnt
> 
> Because the "root" is a fake name. Then I suggest to print id number,
> if the name can't be found. This method not only used for project id
> 0, it used for all user/group/project IDs which no name defined.
> 
> So this patch should be the V3 patch. We can't sure which one is the
> best idea. If anyone have better idea, please tell me.
> 
> Thanks,
> Zorro
> 
>  quota/report.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/quota/report.c b/quota/report.c
> index 48a3f29..557d667 100644
> --- a/quota/report.c
> +++ b/quota/report.c
> @@ -389,7 +389,10 @@ report_mount(
>  					name = p->pr_name;
>  			}
>  		}
> -		fprintf(fp, "%-10s", name);

Could use a comment:

+		/* If no name is found, print the id # instead of (null) */

> +		if (name != NULL)
> +			fprintf(fp, "%-10s", name);
> +		else
> +			fprintf(fp, "#%-10u", d.d_id);
>  	}
>  
>  	if (form & XFS_BLOCK_QUOTA) {
> @@ -571,6 +574,12 @@ report_project_mount(
>  			id = oid + 1;
>  		}
>  	} else {

Comment:

+		/* Print default project quota even if PRID 0 isn't defined */

> +		if (!getprprid(0)) {
> +			report_mount(fp, 0, "#0", NULL, form, XFS_PROJ_QUOTA,

If you pass in NULL instead of "#0" does report_mount do the right thing?
If so, better to not hard-code "#0" here.

-Eric

> +			             mount, flags);
> +			flags |= NO_HEADER_FLAG;
> +		}
> +
>  		setprent();
>  		while ((p = getprent()) != NULL) {
>  			if (report_mount(fp, p->pr_prid, p->pr_name, NULL,
> 

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