libnvdimm: write pmem label set

After 'uuid', 'size', and optionally 'alt_name' have been set to valid
values the labels on the dimms can be updated.

Write procedure is:
1/ Allocate and write new labels in the "next" index
2/ Free the old labels in the working copy
3/ Write the bitmap and the label space on the dimm
4/ Write the index to make the update valid

Label ranges directly mirror the dpa resource values for the given
label_id of the namespace.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/dimm_devs.c

@@ -132,6 +132,55 @@ int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
 	return rc;
 }
 
+int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
+		void *buf, size_t len)
+{
+	int rc = validate_dimm(ndd);
+	size_t max_cmd_size, buf_offset;
+	struct nd_cmd_set_config_hdr *cmd;
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
+
+	if (rc)
+		return rc;
+
+	if (!ndd->data)
+		return -ENXIO;
+
+	if (offset + len > ndd->nsarea.config_size)
+		return -ENXIO;
+
+	max_cmd_size = min_t(u32, PAGE_SIZE, len);
+	max_cmd_size = min_t(u32, max_cmd_size, ndd->nsarea.max_xfer);
+	cmd = kzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	for (buf_offset = 0; len; len -= cmd->in_length,
+			buf_offset += cmd->in_length) {
+		size_t cmd_size;
+		u32 *status;
+
+		cmd->in_offset = offset + buf_offset;
+		cmd->in_length = min(max_cmd_size, len);
+		memcpy(cmd->in_buf, buf + buf_offset, cmd->in_length);
+
+		/* status is output in the last 4-bytes of the command buffer */
+		cmd_size = sizeof(*cmd) + cmd->in_length + sizeof(u32);
+		status = ((void *) cmd) + cmd_size - sizeof(u32);
+
+		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
+				ND_CMD_SET_CONFIG_DATA, cmd, cmd_size);
+		if (rc || *status) {
+			rc = rc ? rc : -ENXIO;
+			break;
+		}
+	}
+	kfree(cmd);
+
+	return rc;
+}
+
 static void nvdimm_release(struct device *dev)
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);

drivers/nvdimm/label.h

@@ -34,6 +34,7 @@ enum {
 	BTTINFO_MAJOR_VERSION = 1,
 	ND_LABEL_MIN_SIZE = 512 * 129, /* see sizeof_namespace_index() */
 	ND_LABEL_ID_SIZE = 50,
+	ND_NSINDEX_INIT = 0x1,
 };
 
 static const char NSINDEX_SIGNATURE[] = "NAMESPACE_INDEX\0";
@@ -127,4 +128,9 @@ void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
 size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);
 int nd_label_active_count(struct nvdimm_drvdata *ndd);
 struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
+u32 nd_label_nfree(struct nvdimm_drvdata *ndd);
+struct nd_region;
+struct nd_namespace_pmem;
+int nd_pmem_namespace_label_update(struct nd_region *nd_region,
+		struct nd_namespace_pmem *nspm, resource_size_t size);
 #endif /* __LABEL_H__ */

drivers/nvdimm/namespace_devs.c

@@ -149,20 +149,53 @@ static resource_size_t nd_namespace_blk_size(struct nd_namespace_blk *nsblk)
 	return size;
 }
 
+static int nd_namespace_label_update(struct nd_region *nd_region,
+		struct device *dev)
+{
+	dev_WARN_ONCE(dev, dev->driver,
+			"namespace must be idle during label update\n");
+	if (dev->driver)
+		return 0;
+
+	/*
+	 * Only allow label writes that will result in a valid namespace
+	 * or deletion of an existing namespace.
+	 */
+	if (is_namespace_pmem(dev)) {
+		struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
+		struct resource *res = &nspm->nsio.res;
+		resource_size_t size = resource_size(res);
+
+		if (size == 0 && nspm->uuid)
+			/* delete allocation */;
+		else if (!nspm->uuid)
+			return 0;
+
+		return nd_pmem_namespace_label_update(nd_region, nspm, size);
+	} else if (is_namespace_blk(dev)) {
+		/* TODO: implement blk labels */
+		return 0;
+	} else
+		return -ENXIO;
+}
+
 static ssize_t alt_name_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
+	struct nd_region *nd_region = to_nd_region(dev->parent);
 	ssize_t rc;
 
 	device_lock(dev);
 	nvdimm_bus_lock(dev);
 	wait_nvdimm_bus_probe_idle(dev);
 	rc = __alt_name_store(dev, buf, len);
+	if (rc >= 0)
+		rc = nd_namespace_label_update(nd_region, dev);
 	dev_dbg(dev, "%s: %s(%zd)\n", __func__, rc < 0 ? "fail " : "", rc);
 	nvdimm_bus_unlock(dev);
 	device_unlock(dev);
 
-	return rc;
+	return rc < 0 ? rc : len;
 }
 
 static ssize_t alt_name_show(struct device *dev,
@@ -709,6 +742,7 @@ static ssize_t __size_store(struct device *dev, unsigned long long val)
 static ssize_t size_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
+	struct nd_region *nd_region = to_nd_region(dev->parent);
 	unsigned long long val;
 	u8 **uuid = NULL;
 	int rc;
@@ -721,6 +755,8 @@ static ssize_t size_store(struct device *dev,
 	nvdimm_bus_lock(dev);
 	wait_nvdimm_bus_probe_idle(dev);
 	rc = __size_store(dev, val);
+	if (rc >= 0)
+		rc = nd_namespace_label_update(nd_region, dev);
 
 	if (is_namespace_pmem(dev)) {
 		struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
@@ -744,7 +780,7 @@ static ssize_t size_store(struct device *dev,
 	nvdimm_bus_unlock(dev);
 	device_unlock(dev);
 
-	return rc ? rc : len;
+	return rc < 0 ? rc : len;
 }
 
 static ssize_t size_show(struct device *dev,
@@ -804,17 +840,34 @@ static int namespace_update_uuid(struct nd_region *nd_region,
 	u32 flags = is_namespace_blk(dev) ? NSLABEL_FLAG_LOCAL : 0;
 	struct nd_label_id old_label_id;
 	struct nd_label_id new_label_id;
-	int i, rc;
+	int i;
 
-	rc = nd_is_uuid_unique(dev, new_uuid) ? 0 : -EINVAL;
-	if (rc) {
-		kfree(new_uuid);
-		return rc;
-	}
+	if (!nd_is_uuid_unique(dev, new_uuid))
+		return -EINVAL;
 
 	if (*old_uuid == NULL)
 		goto out;
 
+	/*
+	 * If we've already written a label with this uuid, then it's
+	 * too late to rename because we can't reliably update the uuid
+	 * without losing the old namespace.  Userspace must delete this
+	 * namespace to abandon the old uuid.
+	 */
+	for (i = 0; i < nd_region->ndr_mappings; i++) {
+		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+
+		/*
+		 * This check by itself is sufficient because old_uuid
+		 * would be NULL above if this uuid did not exist in the
+		 * currently written set.
+		 *
+		 * FIXME: can we delete uuid with zero dpa allocated?
+		 */
+		if (nd_mapping->labels)
+			return -EBUSY;
+	}
+
 	nd_label_gen_id(&old_label_id, *old_uuid, flags);
 	nd_label_gen_id(&new_label_id, new_uuid, flags);
 	for (i = 0; i < nd_region->ndr_mappings; i++) {
@@ -858,12 +911,16 @@ static ssize_t uuid_store(struct device *dev,
 	rc = nd_uuid_store(dev, &uuid, buf, len);
 	if (rc >= 0)
 		rc = namespace_update_uuid(nd_region, dev, uuid, ns_uuid);
+	if (rc >= 0)
+		rc = nd_namespace_label_update(nd_region, dev);
+	else
+		kfree(uuid);
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 	nvdimm_bus_unlock(dev);
 	device_unlock(dev);
 
-	return rc ? rc : len;
+	return rc < 0 ? rc : len;
 }
 static DEVICE_ATTR_RW(uuid);
 
@@ -907,6 +964,7 @@ static ssize_t sector_size_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
+	struct nd_region *nd_region = to_nd_region(dev->parent);
 	ssize_t rc;
 
 	if (!is_namespace_blk(dev))
@@ -916,8 +974,11 @@ static ssize_t sector_size_store(struct device *dev,
 	nvdimm_bus_lock(dev);
 	rc = nd_sector_size_store(dev, buf, &nsblk->lbasize,
 			ns_lbasize_supported);
-	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
-			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
+	if (rc >= 0)
+		rc = nd_namespace_label_update(nd_region, dev);
+	dev_dbg(dev, "%s: result: %zd %s: %s%s", __func__,
+			rc, rc < 0 ? "tried" : "wrote", buf,
+			buf[len - 1] == '\n' ? "" : "\n");
 	nvdimm_bus_unlock(dev);
 	device_unlock(dev);
 

drivers/nvdimm/nd.h

@@ -93,6 +93,7 @@ static inline unsigned nd_inc_seq(unsigned seq)
 
 	return next[seq & 3];
 }
+
 enum nd_async_mode {
 	ND_SYNC,
 	ND_ASYNC,
@@ -115,6 +116,8 @@ struct nvdimm;
 struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping);
 int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
 int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
+int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
+		void *buf, size_t len);
 struct nd_region *to_nd_region(struct device *dev);
 int nd_region_to_nstype(struct nd_region *nd_region);
 int nd_region_register_namespaces(struct nd_region *nd_region, int *err);