[PATCH] libxcmd: fix counting of xfs entries in fs_table_insert

[Eryu Guan]

On Sun, Sep 25, 2016 at 07:31:55AM -0700, Christoph Hellwig wrote:
> On Sun, Sep 25, 2016 at 06:09:22PM +0800, Eryu Guan wrote:
> > Commit bb80e3d6cd04 ("libxcmd: populate fs table with xfs entries
> > first, foreign entries last") adds a new counter "xfs_fs_count" and
> > increases the counter when inserting an XFS entry.
> > 
> > But it missed a counter when fs_count is zero (inserting the first
> > path) and the entry has no FS_FOREIGN bit set, i.e. the first XFS
> > entry doesn't increase xfs_fs_count.
> > 
> > This results in args_command() mess and infinite loop in xfs/244
> > when testing v4 XFS (xfs/244 notrun on v5 XFS, but this bug still
> > reproduces on v5 XFS). e.g.
> > 
> >   mkfs -t xfs -f /dev/sda5
> >   mount -o pquota /dev/sda5 /mnt/xfs
> >   mkdir /mnt/xfs/project
> >   touch /mnt/xfs/project/testfile
> >   xfs_quota -x -c "project -s -p /mnt/xfs/project/testfile 1" /dev/sda5
> > 
> > Fix it by increasing xfs_fs_count when flags has no FS_FOREIGN bit.
> 
> Looks ifne,
> 
> Reviewed-by: Christoph Hellwig <hch at lst.de>
> 
> Can I assume you'll add the above test to xfstests?

It's already part of xfs/244, I noticed this bug because xfs/244 kept
running. I just put the minimum steps in commit log. So I think we're
good :)

Thanks,
Eryu