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Commit 4a826c83 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent eaf96153

drivers/nvdimm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ libnvdimm-y += dimm.o 
libnvdimm-y += region_devs.o

libnvdimm-y += region.o

libnvdimm-y += namespace_devs.o

libnvdimm-y += label.o

drivers/nvdimm/dimm.c

+23 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/slab.h>

#include <linux/mm.h>

#include <linux/nd.h>

#include "label.h"

#include "nd.h"



static void free_data(struct nvdimm_drvdata *ndd)
@@ -42,6 +43,11 @@ static int nvdimm_probe(struct device *dev) 
		return -ENOMEM;



	dev_set_drvdata(dev, ndd);

	ndd->dpa.name = dev_name(dev);

	ndd->ns_current = -1;

	ndd->ns_next = -1;

	ndd->dpa.start = 0;

	ndd->dpa.end = -1;

	ndd->dev = dev;



	rc = nvdimm_init_nsarea(ndd);
@@ -54,6 +60,17 @@ static int nvdimm_probe(struct device *dev) 


	dev_dbg(dev, "config data size: %d\n", ndd->nsarea.config_size);



	nvdimm_bus_lock(dev);

	ndd->ns_current = nd_label_validate(ndd);

	ndd->ns_next = nd_label_next_nsindex(ndd->ns_current);

	nd_label_copy(ndd, to_next_namespace_index(ndd),

			to_current_namespace_index(ndd));

	rc = nd_label_reserve_dpa(ndd);

	nvdimm_bus_unlock(dev);



	if (rc)

		goto err;



	return 0;



 err:
@@ -64,7 +81,13 @@ static int nvdimm_probe(struct device *dev) 
static int nvdimm_remove(struct device *dev)

{

	struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);

	struct resource *res, *_r;



	nvdimm_bus_lock(dev);

	dev_set_drvdata(dev, NULL);

	for_each_dpa_resource_safe(ndd, res, _r)

		nvdimm_free_dpa(ndd, res);

	nvdimm_bus_unlock(dev);

	free_data(ndd);



	return 0;

drivers/nvdimm/dimm_devs.c

+29 −1
Original line number Diff line number Diff line
@@ -92,8 +92,12 @@ int nvdimm_init_config_data(struct nvdimm_drvdata *ndd) 
	if (ndd->data)

		return 0;



	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0)

	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0

			|| ndd->nsarea.config_size < ND_LABEL_MIN_SIZE) {

		dev_dbg(ndd->dev, "failed to init config data area: (%d:%d)\n",

				ndd->nsarea.max_xfer, ndd->nsarea.config_size);

		return -ENXIO;

	}



	ndd->data = kmalloc(ndd->nsarea.config_size, GFP_KERNEL);

	if (!ndd->data)
@@ -243,6 +247,30 @@ struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data, 
}

EXPORT_SYMBOL_GPL(nvdimm_create);



void nvdimm_free_dpa(struct nvdimm_drvdata *ndd, struct resource *res)

{

	WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));

	kfree(res->name);

	__release_region(&ndd->dpa, res->start, resource_size(res));

}



struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd,

		struct nd_label_id *label_id, resource_size_t start,

		resource_size_t n)

{

	char *name = kmemdup(label_id, sizeof(*label_id), GFP_KERNEL);

	struct resource *res;



	if (!name)

		return NULL;



	WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));

	res = __request_region(&ndd->dpa, start, n, name, 0);

	if (!res)

		kfree(name);

	return res;

}



static int count_dimms(struct device *dev, void *c)

{

	int *count = c;

drivers/nvdimm/label.c

0 → 100644
+290 −0
Original line number Diff line number Diff line 
/*

 * 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;

}

drivers/nvdimm/label.h

0 → 100644
+128 −0
Original line number Diff line number Diff line 
/*

 * 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.

 */

#ifndef __LABEL_H__

#define __LABEL_H__



#include <linux/ndctl.h>

#include <linux/sizes.h>

#include <linux/io.h>



enum {

	NSINDEX_SIG_LEN = 16,

	NSINDEX_ALIGN = 256,

	NSINDEX_SEQ_MASK = 0x3,

	NSLABEL_UUID_LEN = 16,

	NSLABEL_NAME_LEN = 64,

	NSLABEL_FLAG_ROLABEL = 0x1,  /* read-only label */

	NSLABEL_FLAG_LOCAL = 0x2,    /* DIMM-local namespace */

	NSLABEL_FLAG_BTT = 0x4,      /* namespace contains a BTT */

	NSLABEL_FLAG_UPDATING = 0x8, /* label being updated */

	BTT_ALIGN = 4096,            /* all btt structures */

	BTTINFO_SIG_LEN = 16,

	BTTINFO_UUID_LEN = 16,

	BTTINFO_FLAG_ERROR = 0x1,    /* error state (read-only) */

	BTTINFO_MAJOR_VERSION = 1,

	ND_LABEL_MIN_SIZE = 512 * 129, /* see sizeof_namespace_index() */

	ND_LABEL_ID_SIZE = 50,

};



static const char NSINDEX_SIGNATURE[] = "NAMESPACE_INDEX\0";



/**

 * struct nd_namespace_index - label set superblock

 * @sig: NAMESPACE_INDEX\0

 * @flags: placeholder

 * @seq: sequence number for this index

 * @myoff: offset of this index in label area

 * @mysize: size of this index struct

 * @otheroff: offset of other index

 * @labeloff: offset of first label slot

 * @nslot: total number of label slots

 * @major: label area major version

 * @minor: label area minor version

 * @checksum: fletcher64 of all fields

 * @free[0]: bitmap, nlabel bits

 *

 * The size of free[] is rounded up so the total struct size is a

 * multiple of NSINDEX_ALIGN bytes.  Any bits this allocates beyond

 * nlabel bits must be zero.

 */

struct nd_namespace_index {

	u8 sig[NSINDEX_SIG_LEN];

	__le32 flags;

	__le32 seq;

	__le64 myoff;

	__le64 mysize;

	__le64 otheroff;

	__le64 labeloff;

	__le32 nslot;

	__le16 major;

	__le16 minor;

	__le64 checksum;

	u8 free[0];

};



/**

 * struct nd_namespace_label - namespace superblock

 * @uuid: UUID per RFC 4122

 * @name: optional name (NULL-terminated)

 * @flags: see NSLABEL_FLAG_*

 * @nlabel: num labels to describe this ns

 * @position: labels position in set

 * @isetcookie: interleave set cookie

 * @lbasize: LBA size in bytes or 0 for pmem

 * @dpa: DPA of NVM range on this DIMM

 * @rawsize: size of namespace

 * @slot: slot of this label in label area

 * @unused: must be zero

 */

struct nd_namespace_label {

	u8 uuid[NSLABEL_UUID_LEN];

	u8 name[NSLABEL_NAME_LEN];

	__le32 flags;

	__le16 nlabel;

	__le16 position;

	__le64 isetcookie;

	__le64 lbasize;

	__le64 dpa;

	__le64 rawsize;

	__le32 slot;

	__le32 unused;

};



/**

 * struct nd_label_id - identifier string for dpa allocation

 * @id: "{blk|pmem}-<namespace uuid>"

 */

struct nd_label_id {

	char id[ND_LABEL_ID_SIZE];

};



/*

 * If the 'best' index is invalid, so is the 'next' index.  Otherwise,

 * the next index is MOD(index+1, 2)

 */

static inline int nd_label_next_nsindex(int index)

{

	if (index < 0)

		return -1;



	return (index + 1) % 2;

}



struct nvdimm_drvdata;

int nd_label_validate(struct nvdimm_drvdata *ndd);

void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,

		struct nd_namespace_index *src);

size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);

#endif /* __LABEL_H__ */