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author | Dan Williams <dan.j.williams@intel.com> | 2015-06-09 16:09:36 -0400 |
---|---|---|
committer | Dan Williams <dan.j.williams@intel.com> | 2015-06-24 21:24:10 -0400 |
commit | 4a826c83db4edc040da3a66dbefd53f0cfcf457d (patch) | |
tree | ff26d9df31e46d3f7d8ff12fa288982460beacc3 /drivers/nvdimm/label.c | |
parent | eaf961536e1622ad21247ac8d44acd48ba65566e (diff) | |
download | linux-4a826c83db4edc040da3a66dbefd53f0cfcf457d.tar.gz linux-4a826c83db4edc040da3a66dbefd53f0cfcf457d.tar.bz2 linux-4a826c83db4edc040da3a66dbefd53f0cfcf457d.zip |
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>
Diffstat (limited to 'drivers/nvdimm/label.c')
-rw-r--r-- | drivers/nvdimm/label.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c new file mode 100644 index 000000000000..db5d7492dc8d --- /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; +} |