libnvdimm: namespace indices: read and validate
This on media label format [1] consists of two index blocks followed by
an array of labels. None of these structures are ever updated in place.
A sequence number tracks the current active index and the next one to
write, while labels are written to free slots.
+------------+
| |
| nsindex0 |
| |
+------------+
| |
| nsindex1 |
| |
+------------+
| label0 |
+------------+
| label1 |
+------------+
| |
....nslot...
| |
+------------+
| labelN |
+------------+
After reading valid labels, store the dpa ranges they claim into
per-dimm resource trees.
[1]: http://pmem.io/documents/NVDIMM_Namespace_Spec.pdf
Cc: Neil Brown <neilb@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
new file mode 100644
index 0000000..db5d749
--- /dev/null
+++ b/drivers/nvdimm/label.c
@@ -0,0 +1,290 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/device.h>
+#include <linux/ndctl.h>
+#include <linux/io.h>
+#include <linux/nd.h>
+#include "nd-core.h"
+#include "label.h"
+#include "nd.h"
+
+static u32 best_seq(u32 a, u32 b)
+{
+ a &= NSINDEX_SEQ_MASK;
+ b &= NSINDEX_SEQ_MASK;
+
+ if (a == 0 || a == b)
+ return b;
+ else if (b == 0)
+ return a;
+ else if (nd_inc_seq(a) == b)
+ return b;
+ else
+ return a;
+}
+
+size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd)
+{
+ u32 index_span;
+
+ if (ndd->nsindex_size)
+ return ndd->nsindex_size;
+
+ /*
+ * The minimum index space is 512 bytes, with that amount of
+ * index we can describe ~1400 labels which is less than a byte
+ * of overhead per label. Round up to a byte of overhead per
+ * label and determine the size of the index region. Yes, this
+ * starts to waste space at larger config_sizes, but it's
+ * unlikely we'll ever see anything but 128K.
+ */
+ index_span = ndd->nsarea.config_size / 129;
+ index_span /= NSINDEX_ALIGN * 2;
+ ndd->nsindex_size = index_span * NSINDEX_ALIGN;
+
+ return ndd->nsindex_size;
+}
+
+int nd_label_validate(struct nvdimm_drvdata *ndd)
+{
+ /*
+ * On media label format consists of two index blocks followed
+ * by an array of labels. None of these structures are ever
+ * updated in place. A sequence number tracks the current
+ * active index and the next one to write, while labels are
+ * written to free slots.
+ *
+ * +------------+
+ * | |
+ * | nsindex0 |
+ * | |
+ * +------------+
+ * | |
+ * | nsindex1 |
+ * | |
+ * +------------+
+ * | label0 |
+ * +------------+
+ * | label1 |
+ * +------------+
+ * | |
+ * ....nslot...
+ * | |
+ * +------------+
+ * | labelN |
+ * +------------+
+ */
+ struct nd_namespace_index *nsindex[] = {
+ to_namespace_index(ndd, 0),
+ to_namespace_index(ndd, 1),
+ };
+ const int num_index = ARRAY_SIZE(nsindex);
+ struct device *dev = ndd->dev;
+ bool valid[2] = { 0 };
+ int i, num_valid = 0;
+ u32 seq;
+
+ for (i = 0; i < num_index; i++) {
+ u32 nslot;
+ u8 sig[NSINDEX_SIG_LEN];
+ u64 sum_save, sum, size;
+
+ memcpy(sig, nsindex[i]->sig, NSINDEX_SIG_LEN);
+ if (memcmp(sig, NSINDEX_SIGNATURE, NSINDEX_SIG_LEN) != 0) {
+ dev_dbg(dev, "%s: nsindex%d signature invalid\n",
+ __func__, i);
+ continue;
+ }
+ sum_save = __le64_to_cpu(nsindex[i]->checksum);
+ nsindex[i]->checksum = __cpu_to_le64(0);
+ sum = nd_fletcher64(nsindex[i], sizeof_namespace_index(ndd), 1);
+ nsindex[i]->checksum = __cpu_to_le64(sum_save);
+ if (sum != sum_save) {
+ dev_dbg(dev, "%s: nsindex%d checksum invalid\n",
+ __func__, i);
+ continue;
+ }
+
+ seq = __le32_to_cpu(nsindex[i]->seq);
+ if ((seq & NSINDEX_SEQ_MASK) == 0) {
+ dev_dbg(dev, "%s: nsindex%d sequence: %#x invalid\n",
+ __func__, i, seq);
+ continue;
+ }
+
+ /* sanity check the index against expected values */
+ if (__le64_to_cpu(nsindex[i]->myoff)
+ != i * sizeof_namespace_index(ndd)) {
+ dev_dbg(dev, "%s: nsindex%d myoff: %#llx invalid\n",
+ __func__, i, (unsigned long long)
+ __le64_to_cpu(nsindex[i]->myoff));
+ continue;
+ }
+ if (__le64_to_cpu(nsindex[i]->otheroff)
+ != (!i) * sizeof_namespace_index(ndd)) {
+ dev_dbg(dev, "%s: nsindex%d otheroff: %#llx invalid\n",
+ __func__, i, (unsigned long long)
+ __le64_to_cpu(nsindex[i]->otheroff));
+ continue;
+ }
+
+ size = __le64_to_cpu(nsindex[i]->mysize);
+ if (size > sizeof_namespace_index(ndd)
+ || size < sizeof(struct nd_namespace_index)) {
+ dev_dbg(dev, "%s: nsindex%d mysize: %#llx invalid\n",
+ __func__, i, size);
+ continue;
+ }
+
+ nslot = __le32_to_cpu(nsindex[i]->nslot);
+ if (nslot * sizeof(struct nd_namespace_label)
+ + 2 * sizeof_namespace_index(ndd)
+ > ndd->nsarea.config_size) {
+ dev_dbg(dev, "%s: nsindex%d nslot: %u invalid, config_size: %#x\n",
+ __func__, i, nslot,
+ ndd->nsarea.config_size);
+ continue;
+ }
+ valid[i] = true;
+ num_valid++;
+ }
+
+ switch (num_valid) {
+ case 0:
+ break;
+ case 1:
+ for (i = 0; i < num_index; i++)
+ if (valid[i])
+ return i;
+ /* can't have num_valid > 0 but valid[] = { false, false } */
+ WARN_ON(1);
+ break;
+ default:
+ /* pick the best index... */
+ seq = best_seq(__le32_to_cpu(nsindex[0]->seq),
+ __le32_to_cpu(nsindex[1]->seq));
+ if (seq == (__le32_to_cpu(nsindex[1]->seq) & NSINDEX_SEQ_MASK))
+ return 1;
+ else
+ return 0;
+ break;
+ }
+
+ return -1;
+}
+
+void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
+ struct nd_namespace_index *src)
+{
+ if (dst && src)
+ /* pass */;
+ else
+ return;
+
+ memcpy(dst, src, sizeof_namespace_index(ndd));
+}
+
+static struct nd_namespace_label *nd_label_base(struct nvdimm_drvdata *ndd)
+{
+ void *base = to_namespace_index(ndd, 0);
+
+ return base + 2 * sizeof_namespace_index(ndd);
+}
+
+#define for_each_clear_bit_le(bit, addr, size) \
+ for ((bit) = find_next_zero_bit_le((addr), (size), 0); \
+ (bit) < (size); \
+ (bit) = find_next_zero_bit_le((addr), (size), (bit) + 1))
+
+/**
+ * preamble_current - common variable initialization for nd_label_* routines
+ * @ndd: dimm container for the relevant label set
+ * @nsindex_out: on return set to the currently active namespace index
+ * @free: on return set to the free label bitmap in the index
+ * @nslot: on return set to the number of slots in the label space
+ */
+static bool preamble_current(struct nvdimm_drvdata *ndd,
+ struct nd_namespace_index **nsindex_out,
+ unsigned long **free, u32 *nslot)
+{
+ struct nd_namespace_index *nsindex;
+
+ nsindex = to_current_namespace_index(ndd);
+ if (nsindex == NULL)
+ return false;
+
+ *free = (unsigned long *) nsindex->free;
+ *nslot = __le32_to_cpu(nsindex->nslot);
+ *nsindex_out = nsindex;
+
+ return true;
+}
+
+static char *nd_label_gen_id(struct nd_label_id *label_id, u8 *uuid, u32 flags)
+{
+ if (!label_id || !uuid)
+ return NULL;
+ snprintf(label_id->id, ND_LABEL_ID_SIZE, "%s-%pUb",
+ flags & NSLABEL_FLAG_LOCAL ? "blk" : "pmem", uuid);
+ return label_id->id;
+}
+
+static bool slot_valid(struct nd_namespace_label *nd_label, u32 slot)
+{
+ /* check that we are written where we expect to be written */
+ if (slot != __le32_to_cpu(nd_label->slot))
+ return false;
+
+ /* check that DPA allocations are page aligned */
+ if ((__le64_to_cpu(nd_label->dpa)
+ | __le64_to_cpu(nd_label->rawsize)) % SZ_4K)
+ return false;
+
+ return true;
+}
+
+int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
+{
+ struct nd_namespace_index *nsindex;
+ unsigned long *free;
+ u32 nslot, slot;
+
+ if (!preamble_current(ndd, &nsindex, &free, &nslot))
+ return 0; /* no label, nothing to reserve */
+
+ for_each_clear_bit_le(slot, free, nslot) {
+ struct nd_namespace_label *nd_label;
+ struct nd_region *nd_region = NULL;
+ u8 label_uuid[NSLABEL_UUID_LEN];
+ struct nd_label_id label_id;
+ struct resource *res;
+ u32 flags;
+
+ nd_label = nd_label_base(ndd) + slot;
+
+ if (!slot_valid(nd_label, slot))
+ continue;
+
+ memcpy(label_uuid, nd_label->uuid, NSLABEL_UUID_LEN);
+ flags = __le32_to_cpu(nd_label->flags);
+ nd_label_gen_id(&label_id, label_uuid, flags);
+ res = nvdimm_allocate_dpa(ndd, &label_id,
+ __le64_to_cpu(nd_label->dpa),
+ __le64_to_cpu(nd_label->rawsize));
+ nd_dbg_dpa(nd_region, ndd, res, "reserve\n");
+ if (!res)
+ return -EBUSY;
+ }
+
+ return 0;
+}
