Commit d11bb446 authored by Wanlong Gao's avatar Wanlong Gao Committed by Jens Axboe
Browse files

blk-cgroup: be able to remove the record of unplugged device 



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: default avatarWanlong Gao <gaowanlong@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <paul@paulmenage.org>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8ad6a56f

block/blk-cgroup.c

+16 −21
Original line number Diff line number Diff line
@@ -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));
@@ -826,19 +826,22 @@ static int blkio_policy_parse_and_set(char *buf, 


	dev = MKDEV(major, minor);



	ret = strict_strtoull(s[1], 10, &temp);

	if (ret)

		return -EINVAL;



	/* For rule removal, do not check for device presence. */

	if (temp) {

		ret = blkio_check_dev_num(dev);

		if (ret)

			return ret;

	}



	newpn->dev = dev;



	if (s[1] == NULL)

		return -EINVAL;



	switch (plid) {

	case BLKIO_POLICY_PROP:

		ret = strict_strtoul(s[1], 10, &temp);

		if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||

		if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||

		     temp > BLKIO_WEIGHT_MAX)

			return -EINVAL;
@@ -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;

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