Re: [PATCH v5] blk-cgroup:be able to remove the record of unplugged device

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Aug 17, 2011 at 08:57:45PM +0800, Wanlong Gao wrote:
> On Wed, 2011-07-27 at 10:11 -0400, Vivek Goyal wrote:
> > On Wed, Jul 27, 2011 at 08:11:48AM +0800, Wanlong Gao wrote:
> > > The bug is we're not able to remove the device from blkio cgroup's
> > > per-device control files if it gets unplugged.
> > > 
> > > To reproduce the bug:
> > > 
> > >   # mount -t cgroup -o blkio xxx /cgroup
> > >   # cd /cgroup
> > >   # echo "8:0 1000" > blkio.throttle.read_bps_device
> > >   # unplug the device
> > >   # cat blkio.throttle.read_bps_device
> > >   8:0	1000
> > >   # echo "8:0 0" > blkio.throttle.read_bps_device
> > >   -bash: echo: write error: No such device
> > > 
> > > After patching, the device removal will succeed.
> > > 
> > > Thanks for the comments of Paul, Zefan, and Vivek.
> > > 
> > > Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
> > 
> > Thanks. This looks good to me.
> > 
> > Acked-by: Vivek Goyal <vgoyal@redhat.com>
> > 
> > Vivek
> > 
> > > ---
> > >  block/blk-cgroup.c |   37 ++++++++++++++++---------------------
> > >  1 files changed, 16 insertions(+), 21 deletions(-)
> > > 
> > > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> > > index bcaf16e..b596e54 100644
> > > --- a/block/blk-cgroup.c
> > > +++ b/block/blk-cgroup.c
> > > @@ -785,10 +785,10 @@ static int blkio_policy_parse_and_set(char *buf,
> > >  {
> > >  	char *s[4], *p, *major_s = NULL, *minor_s = NULL;
> > >  	int ret;
> > > -	unsigned long major, minor, temp;
> > > +	unsigned long major, minor;
> > >  	int i = 0;
> > >  	dev_t dev;
> > > -	u64 bps, iops;
> > > +	u64 temp;
> > >  
> > >  	memset(s, 0, sizeof(s));
> > >  
> > > @@ -826,20 +826,23 @@ static int blkio_policy_parse_and_set(char *buf,
> > >  
> > >  	dev = MKDEV(major, minor);
> > >  
> > > -	ret = blkio_check_dev_num(dev);
> > > +	ret = strict_strtoull(s[1], 10, &temp);
> > >  	if (ret)
> > > -		return ret;
> > > +		return -EINVAL;
> > >  
> > > -	newpn->dev = dev;
> > > +	/* For rule removal, do not check for device presence. */
> > > +	if (temp) {
> > > +		ret = blkio_check_dev_num(dev);
> > > +		if (ret)
> > > +			return ret;
> > > +	}
> > >  
> > > -	if (s[1] == NULL)
> > > -		return -EINVAL;
> > > +	newpn->dev = dev;
> > >  
> > >  	switch (plid) {
> > >  	case BLKIO_POLICY_PROP:
> > > -		ret = strict_strtoul(s[1], 10, &temp);
> > > -		if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
> > > -			temp > BLKIO_WEIGHT_MAX)
> > > +		if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
> > > +		     temp > BLKIO_WEIGHT_MAX)
> > >  			return -EINVAL;
> > >  
> > >  		newpn->plid = plid;
> > > @@ -850,26 +853,18 @@ static int blkio_policy_parse_and_set(char *buf,
> > >  		switch(fileid) {
> > >  		case BLKIO_THROTL_read_bps_device:
> > >  		case BLKIO_THROTL_write_bps_device:
> > > -			ret = strict_strtoull(s[1], 10, &bps);
> > > -			if (ret)
> > > -				return -EINVAL;
> > > -
> > >  			newpn->plid = plid;
> > >  			newpn->fileid = fileid;
> > > -			newpn->val.bps = bps;
> > > +			newpn->val.bps = temp;
> > >  			break;
> > >  		case BLKIO_THROTL_read_iops_device:
> > >  		case BLKIO_THROTL_write_iops_device:
> > > -			ret = strict_strtoull(s[1], 10, &iops);
> > > -			if (ret)
> > > -				return -EINVAL;
> > > -
> > > -			if (iops > THROTL_IOPS_MAX)
> > > +			if (temp > THROTL_IOPS_MAX)
> > >  				return -EINVAL;
> > >  
> > >  			newpn->plid = plid;
> > >  			newpn->fileid = fileid;
> > > -			newpn->val.iops = (unsigned int)iops;
> > > +			newpn->val.iops = (unsigned int)temp;
> > >  			break;
> > >  		}
> > >  		break;
> > > -- 
> > > 1.7.6
> 
> How about this? For a long time.

I have already acked this patch. Jens, what do you think about it.

Thanks
Vivek