[10/10] rbd: distribute scsi pr info through rbd class calls

Commit Message

Mike Christie April 28, 2015, 10:05 p.m. UTC

From: Mike Christie <[e-mail]>

This stores the LIO PR info in the rbd header. Other
clients (LIO nodes) are notified when the data changes,
so they can update their info.

I added a sysfs file to test it here temporarily. I will
remove it in the final version. The final patches will
have a LIO callout call the rados locking and these
functions instead.

Signed-off-by: Mike Christie <[e-mail]>
---
 drivers/block/rbd.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

Comments

Christoph Hellwig April 30, 2015, 7:56 a.m. UTC | #1

On Tue, Apr 28, 2015 at 05:05:47PM -0500, [e-mail] wrote:
> From: Mike Christie <[e-mail]>
> 
> This stores the LIO PR info in the rbd header. Other
> clients (LIO nodes) are notified when the data changes,
> so they can update their info.
> 
> I added a sysfs file to test it here temporarily. I will
> remove it in the final version. The final patches will
> have a LIO callout call the rados locking and these
> functions instead.

So this is just an RFC and you'll have a real interface later?

I'd be curious what you're planning there as I'll need something similar
for the pNFS scsi-layouts client which will call into the block device
to ask for persistent reservations.
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Patch

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index f4e7b0f..1fa4fd0 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4465,6 +4465,72 @@  static int rbd_dev_break_locks(struct rbd_device *rbd_dev, char *name)
 	return rbd_dev_lock_for_each_locker(rbd_dev, name, rbd_dev_break_lock);
 }
 
+static size_t rbd_dev_set_scsi_pr_info(struct rbd_device *rbd_dev,
+				       const char *info)
+{
+	int info_len = strlen(info);
+	int info_buf_len = info_len + sizeof(__le32);
+	int ret;
+	void *info_buf, *p, *end;
+
+	dout("%s: set scsi pr info %s\n", __func__, info);
+
+	p = info_buf = kzalloc(info_buf_len, GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	end = p + info_buf_len;
+	ceph_encode_string(&p, end, info, info_len);
+
+	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_name,
+				  "rbd", "set_scsi_pr_info", info_buf,
+				  info_buf_len, NULL, 0);
+	if (!ret)
+		rbd_obj_notify_scsi_event_sync(rbd_dev,
+					       RBD_NOTIFY_OP_SCSI_PR_UPDATE, 5);
+	dout("%s: status %d\n", __func__, ret);
+	kfree(info_buf);
+	return ret;
+}
+
+static size_t rbd_dev_get_scsi_pr_info(struct rbd_device *rbd_dev,
+				       char *buf, int buf_len)
+{
+	__le64 snapid;
+	int ret;
+	void *info_buf, *p;
+
+	info_buf = p = kzalloc(buf_len, GFP_KERNEL);
+	if (!info_buf)
+		return -ENOMEM;
+
+	snapid = cpu_to_le64(rbd_dev->spec->snap_id);
+	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_name, "rbd",
+				  "get_scsi_pr_info", &snapid, sizeof(snapid),
+				  info_buf, buf_len);
+	if (ret > sizeof(__le32)) {
+		char *ret_buf;
+		size_t ret_buf_len;
+
+		ret_buf = ceph_extract_encoded_string(&p, p + buf_len,
+						      &ret_buf_len, GFP_KERNEL);
+		if (IS_ERR(ret_buf)) {
+			ret = PTR_ERR(ret_buf);
+			goto free_info_buf;
+		}
+		ret = strlcpy(buf, ret_buf, buf_len);
+		kfree(ret_buf);
+	} else if (ret > 0) {
+		ret = -EINVAL;
+		buf[0] = '\0';
+	}
+
+free_info_buf:
+	kfree(info_buf);
+	dout("%s: returned %d\n", __func__, ret);
+	return ret;
+}
+
 /*
  * TODO: remove me or move to debugfs for final merge. I don't think we
  * need this for upstream since there is already the userspace API
@@ -4555,6 +4621,24 @@  static ssize_t rbd_lock_dump_info_set(struct device *dev,
 		return size;
 }
 
+static ssize_t rbd_scsi_pr_info_set(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t size)
+{
+	int ret = rbd_dev_set_scsi_pr_info(dev_to_rbd_dev(dev), buf);
+
+	if (ret)
+		return ret;
+	else
+		return size;
+}
+
+static ssize_t rbd_scsi_pr_info_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	return rbd_dev_get_scsi_pr_info(dev_to_rbd_dev(dev), buf, PAGE_SIZE);
+}
+
 static DEVICE_ATTR(size, S_IRUGO, rbd_size_show, NULL);
 static DEVICE_ATTR(features, S_IRUGO, rbd_features_show, NULL);
 static DEVICE_ATTR(major, S_IRUGO, rbd_major_show, NULL);
@@ -4571,6 +4655,8 @@  static DEVICE_ATTR(lock, S_IWUSR, NULL, rbd_lock_set);
 static DEVICE_ATTR(unlock, S_IWUSR, NULL, rbd_unlock_set);
 static DEVICE_ATTR(break_locks, S_IWUSR, NULL, rbd_break_locks_set);
 static DEVICE_ATTR(dump_lock_info, S_IWUSR, NULL, rbd_lock_dump_info_set);
+static DEVICE_ATTR(scsi_pr_info, S_IWUSR | S_IRUGO, rbd_scsi_pr_info_show,
+		   rbd_scsi_pr_info_set);
 
 static struct attribute *rbd_attrs[] = {
 	&dev_attr_size.attr,
@@ -4589,6 +4675,7 @@  static struct attribute *rbd_attrs[] = {
 	&dev_attr_unlock.attr,
 	&dev_attr_break_locks.attr,
 	&dev_attr_dump_lock_info.attr,
+	&dev_attr_scsi_pr_info.attr,
 	NULL
 };