drivers/nvdimm/btt.h - linux - Git at Google

 /*
  * Block Translation Table library
  * Copyright (c) 2014-2015, Intel Corporation.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope 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 _LINUX_BTT_H
 #define _LINUX_BTT_H

 #include <linux/badblocks.h>
 #include <linux/types.h>

 #define BTT_SIG_LEN 16
 #define BTT_SIG "BTT_ARENA_INFO\0"
 #define MAP_ENT_SIZE 4
 #define MAP_TRIM_SHIFT 31
 #define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
 #define MAP_ERR_SHIFT 30
 #define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
 #define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
 #define MAP_ENT_NORMAL 0xC0000000
 #define LOG_GRP_SIZE sizeof(struct log_group)
 #define LOG_ENT_SIZE sizeof(struct log_entry)
 #define ARENA_MIN_SIZE (1UL << 24)	/* 16 MB */
 #define ARENA_MAX_SIZE (1ULL << 39)	/* 512 GB */
 #define RTT_VALID (1UL << 31)
 #define RTT_INVALID 0
 #define BTT_PG_SIZE 4096
 #define BTT_DEFAULT_NFREE ND_MAX_LANES
 #define LOG_SEQ_INIT 1

 #define IB_FLAG_ERROR 0x00000001
 #define IB_FLAG_ERROR_MASK 0x00000001

 #define ent_lba(ent) (ent & MAP_LBA_MASK)
 #define ent_e_flag(ent) (!!(ent & MAP_ERR_MASK))
 #define ent_z_flag(ent) (!!(ent & MAP_TRIM_MASK))
 #define set_e_flag(ent) (ent |= MAP_ERR_MASK)
 /* 'normal' is both e and z flags set */
 #define ent_normal(ent) (ent_e_flag(ent) && ent_z_flag(ent))

 enum btt_init_state {
 	INIT_UNCHECKED = 0,
 	INIT_NOTFOUND,
 	INIT_READY
 };

 /*
  * A log group represents one log 'lane', and consists of four log entries.
  * Two of the four entries are valid entries, and the remaining two are
  * padding. Due to an old bug in the padding location, we need to perform a
  * test to determine the padding scheme being used, and use that scheme
  * thereafter.
  *
  * In kernels prior to 4.15, 'log group' would have actual log entries at
  * indices (0, 2) and padding at indices (1, 3), where as the correct/updated
  * format has log entries at indices (0, 1) and padding at indices (2, 3).
  *
  * Old (pre 4.15) format:
  * +-----------------+-----------------+
  * |      ent[0]     |      ent[1]     |
  * |       16B       |       16B       |
  * | lba/old/new/seq |       pad       |
  * +-----------------------------------+
  * |      ent[2]     |      ent[3]     |
  * |       16B       |       16B       |
  * | lba/old/new/seq |       pad       |
  * +-----------------+-----------------+
  *
  * New format:
  * +-----------------+-----------------+
  * |      ent[0]     |      ent[1]     |
  * |       16B       |       16B       |
  * | lba/old/new/seq | lba/old/new/seq |
  * +-----------------------------------+
  * |      ent[2]     |      ent[3]     |
  * |       16B       |       16B       |
  * |       pad       |       pad       |
  * +-----------------+-----------------+
  *
  * We detect during start-up which format is in use, and set
  * arena->log_index[(0, 1)] with the detected format.
  */

 struct log_entry {
 	__le32 lba;
 	__le32 old_map;
 	__le32 new_map;
 	__le32 seq;
 };

 struct log_group {
 	struct log_entry ent[4];
 };

 struct btt_sb {
 	u8 signature[BTT_SIG_LEN];
 	u8 uuid[16];
 	u8 parent_uuid[16];
 	__le32 flags;
 	__le16 version_major;
 	__le16 version_minor;
 	__le32 external_lbasize;
 	__le32 external_nlba;
 	__le32 internal_lbasize;
 	__le32 internal_nlba;
 	__le32 nfree;
 	__le32 infosize;
 	__le64 nextoff;
 	__le64 dataoff;
 	__le64 mapoff;
 	__le64 logoff;
 	__le64 info2off;
 	u8 padding[3968];
 	__le64 checksum;
 };

 struct free_entry {
 	u32 block;
 	u8 sub;
 	u8 seq;
 	u8 has_err;
 };

 struct aligned_lock {
 	union {
 		spinlock_t lock;
 		u8 cacheline_padding[L1_CACHE_BYTES];
 	};
 };

 /**
  * struct arena_info - handle for an arena
  * @size:		Size in bytes this arena occupies on the raw device.
  *			This includes arena metadata.
  * @external_lba_start:	The first external LBA in this arena.
  * @internal_nlba:	Number of internal blocks available in the arena
  *			including nfree reserved blocks
  * @internal_lbasize:	Internal and external lba sizes may be different as
  *			we can round up 'odd' external lbasizes such as 520B
  *			to be aligned.
  * @external_nlba:	Number of blocks contributed by the arena to the number
  *			reported to upper layers. (internal_nlba - nfree)
  * @external_lbasize:	LBA size as exposed to upper layers.
  * @nfree:		A reserve number of 'free' blocks that is used to
  *			handle incoming writes.
  * @version_major:	Metadata layout version major.
  * @version_minor:	Metadata layout version minor.
  * @sector_size:	The Linux sector size - 512 or 4096
  * @nextoff:		Offset in bytes to the start of the next arena.
  * @infooff:		Offset in bytes to the info block of this arena.
  * @dataoff:		Offset in bytes to the data area of this arena.
  * @mapoff:		Offset in bytes to the map area of this arena.
  * @logoff:		Offset in bytes to the log area of this arena.
  * @info2off:		Offset in bytes to the backup info block of this arena.
  * @freelist:		Pointer to in-memory list of free blocks
  * @rtt:		Pointer to in-memory "Read Tracking Table"
  * @map_locks:		Spinlocks protecting concurrent map writes
  * @nd_btt:		Pointer to parent nd_btt structure.
  * @list:		List head for list of arenas
  * @debugfs_dir:	Debugfs dentry
  * @flags:		Arena flags - may signify error states.
  * @err_lock:		Mutex for synchronizing error clearing.
  * @log_index:		Indices of the valid log entries in a log_group
  *
  * arena_info is a per-arena handle. Once an arena is narrowed down for an
  * IO, this struct is passed around for the duration of the IO.
  */
 struct arena_info {
 	u64 size;			/* Total bytes for this arena */
 	u64 external_lba_start;
 	u32 internal_nlba;
 	u32 internal_lbasize;
 	u32 external_nlba;
 	u32 external_lbasize;
 	u32 nfree;
 	u16 version_major;
 	u16 version_minor;
 	u32 sector_size;
 	/* Byte offsets to the different on-media structures */
 	u64 nextoff;
 	u64 infooff;
 	u64 dataoff;
 	u64 mapoff;
 	u64 logoff;
 	u64 info2off;
 	/* Pointers to other in-memory structures for this arena */
 	struct free_entry *freelist;
 	u32 *rtt;
 	struct aligned_lock *map_locks;
 	struct nd_btt *nd_btt;
 	struct list_head list;
 	struct dentry *debugfs_dir;
 	/* Arena flags */
 	u32 flags;
 	struct mutex err_lock;
 	int log_index[2];
 };

 /**
  * struct btt - handle for a BTT instance
  * @btt_disk:		Pointer to the gendisk for BTT device
  * @btt_queue:		Pointer to the request queue for the BTT device
  * @arena_list:		Head of the list of arenas
  * @debugfs_dir:	Debugfs dentry
  * @nd_btt:		Parent nd_btt struct
  * @nlba:		Number of logical blocks exposed to the	upper layers
  *			after removing the amount of space needed by metadata
  * @rawsize:		Total size in bytes of the available backing device
  * @lbasize:		LBA size as requested and presented to upper layers.
  *			This is sector_size + size of any metadata.
  * @sector_size:	The Linux sector size - 512 or 4096
  * @lanes:		Per-lane spinlocks
  * @init_lock:		Mutex used for the BTT initialization
  * @init_state:		Flag describing the initialization state for the BTT
  * @num_arenas:		Number of arenas in the BTT instance
  * @phys_bb:		Pointer to the namespace's badblocks structure
  */
 struct btt {
 	struct gendisk *btt_disk;
 	struct request_queue *btt_queue;
 	struct list_head arena_list;
 	struct dentry *debugfs_dir;
 	struct nd_btt *nd_btt;
 	u64 nlba;
 	unsigned long long rawsize;
 	u32 lbasize;
 	u32 sector_size;
 	struct nd_region *nd_region;
 	struct mutex init_lock;
 	int init_state;
 	int num_arenas;
 	struct badblocks *phys_bb;
 };

 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
 int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
 		struct btt_sb *btt_sb);

 #endif
	/*
	* Block Translation Table library
	* Copyright (c) 2014-2015, Intel Corporation.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope 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 _LINUX_BTT_H
	#define _LINUX_BTT_H

	#include <linux/badblocks.h>
	#include <linux/types.h>

	#define BTT_SIG_LEN 16
	#define BTT_SIG "BTT_ARENA_INFO\0"
	#define MAP_ENT_SIZE 4
	#define MAP_TRIM_SHIFT 31
	#define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
	#define MAP_ERR_SHIFT 30
	#define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
	#define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) \| (1 << MAP_ERR_SHIFT)))
	#define MAP_ENT_NORMAL 0xC0000000
	#define LOG_GRP_SIZE sizeof(struct log_group)
	#define LOG_ENT_SIZE sizeof(struct log_entry)
	#define ARENA_MIN_SIZE (1UL << 24) /* 16 MB */
	#define ARENA_MAX_SIZE (1ULL << 39) /* 512 GB */
	#define RTT_VALID (1UL << 31)
	#define RTT_INVALID 0
	#define BTT_PG_SIZE 4096
	#define BTT_DEFAULT_NFREE ND_MAX_LANES
	#define LOG_SEQ_INIT 1

	#define IB_FLAG_ERROR 0x00000001
	#define IB_FLAG_ERROR_MASK 0x00000001

	#define ent_lba(ent) (ent & MAP_LBA_MASK)
	#define ent_e_flag(ent) (!!(ent & MAP_ERR_MASK))
	#define ent_z_flag(ent) (!!(ent & MAP_TRIM_MASK))
	#define set_e_flag(ent) (ent \|= MAP_ERR_MASK)
	/* 'normal' is both e and z flags set */
	#define ent_normal(ent) (ent_e_flag(ent) && ent_z_flag(ent))

	enum btt_init_state {
	INIT_UNCHECKED = 0,
	INIT_NOTFOUND,
	INIT_READY
	};

	/*
	* A log group represents one log 'lane', and consists of four log entries.
	* Two of the four entries are valid entries, and the remaining two are
	* padding. Due to an old bug in the padding location, we need to perform a
	* test to determine the padding scheme being used, and use that scheme
	* thereafter.
	*
	* In kernels prior to 4.15, 'log group' would have actual log entries at
	* indices (0, 2) and padding at indices (1, 3), where as the correct/updated
	* format has log entries at indices (0, 1) and padding at indices (2, 3).
	*
	* Old (pre 4.15) format:
	* +-----------------+-----------------+
	* \| ent[0] \| ent[1] \|
	* \| 16B \| 16B \|
	* \| lba/old/new/seq \| pad \|
	* +-----------------------------------+
	* \| ent[2] \| ent[3] \|
	* \| 16B \| 16B \|
	* \| lba/old/new/seq \| pad \|
	* +-----------------+-----------------+
	*
	* New format:
	* +-----------------+-----------------+
	* \| ent[0] \| ent[1] \|
	* \| 16B \| 16B \|
	* \| lba/old/new/seq \| lba/old/new/seq \|
	* +-----------------------------------+
	* \| ent[2] \| ent[3] \|
	* \| 16B \| 16B \|
	* \| pad \| pad \|
	* +-----------------+-----------------+
	*
	* We detect during start-up which format is in use, and set
	* arena->log_index[(0, 1)] with the detected format.
	*/

	struct log_entry {
	__le32 lba;
	__le32 old_map;
	__le32 new_map;
	__le32 seq;
	};

	struct log_group {
	struct log_entry ent[4];
	};

	struct btt_sb {
	u8 signature[BTT_SIG_LEN];
	u8 uuid[16];
	u8 parent_uuid[16];
	__le32 flags;
	__le16 version_major;
	__le16 version_minor;
	__le32 external_lbasize;
	__le32 external_nlba;
	__le32 internal_lbasize;
	__le32 internal_nlba;
	__le32 nfree;
	__le32 infosize;
	__le64 nextoff;
	__le64 dataoff;
	__le64 mapoff;
	__le64 logoff;
	__le64 info2off;
	u8 padding[3968];
	__le64 checksum;
	};

	struct free_entry {
	u32 block;
	u8 sub;
	u8 seq;
	u8 has_err;
	};

	struct aligned_lock {
	union {
	spinlock_t lock;
	u8 cacheline_padding[L1_CACHE_BYTES];
	};
	};

	/**
	* struct arena_info - handle for an arena
	* @size: Size in bytes this arena occupies on the raw device.
	* This includes arena metadata.
	* @external_lba_start: The first external LBA in this arena.
	* @internal_nlba: Number of internal blocks available in the arena
	* including nfree reserved blocks
	* @internal_lbasize: Internal and external lba sizes may be different as
	* we can round up 'odd' external lbasizes such as 520B
	* to be aligned.
	* @external_nlba: Number of blocks contributed by the arena to the number
	* reported to upper layers. (internal_nlba - nfree)
	* @external_lbasize: LBA size as exposed to upper layers.
	* @nfree: A reserve number of 'free' blocks that is used to
	* handle incoming writes.
	* @version_major: Metadata layout version major.
	* @version_minor: Metadata layout version minor.
	* @sector_size: The Linux sector size - 512 or 4096
	* @nextoff: Offset in bytes to the start of the next arena.
	* @infooff: Offset in bytes to the info block of this arena.
	* @dataoff: Offset in bytes to the data area of this arena.
	* @mapoff: Offset in bytes to the map area of this arena.
	* @logoff: Offset in bytes to the log area of this arena.
	* @info2off: Offset in bytes to the backup info block of this arena.
	* @freelist: Pointer to in-memory list of free blocks
	* @rtt: Pointer to in-memory "Read Tracking Table"
	* @map_locks: Spinlocks protecting concurrent map writes
	* @nd_btt: Pointer to parent nd_btt structure.
	* @list: List head for list of arenas
	* @debugfs_dir: Debugfs dentry
	* @flags: Arena flags - may signify error states.
	* @err_lock: Mutex for synchronizing error clearing.
	* @log_index: Indices of the valid log entries in a log_group
	*
	* arena_info is a per-arena handle. Once an arena is narrowed down for an
	* IO, this struct is passed around for the duration of the IO.
	*/
	struct arena_info {
	u64 size; /* Total bytes for this arena */
	u64 external_lba_start;
	u32 internal_nlba;
	u32 internal_lbasize;
	u32 external_nlba;
	u32 external_lbasize;
	u32 nfree;
	u16 version_major;
	u16 version_minor;
	u32 sector_size;
	/* Byte offsets to the different on-media structures */
	u64 nextoff;
	u64 infooff;
	u64 dataoff;
	u64 mapoff;
	u64 logoff;
	u64 info2off;
	/* Pointers to other in-memory structures for this arena */
	struct free_entry *freelist;
	u32 *rtt;
	struct aligned_lock *map_locks;
	struct nd_btt *nd_btt;
	struct list_head list;
	struct dentry *debugfs_dir;
	/* Arena flags */
	u32 flags;
	struct mutex err_lock;
	int log_index[2];
	};

	/**
	* struct btt - handle for a BTT instance
	* @btt_disk: Pointer to the gendisk for BTT device
	* @btt_queue: Pointer to the request queue for the BTT device
	* @arena_list: Head of the list of arenas
	* @debugfs_dir: Debugfs dentry
	* @nd_btt: Parent nd_btt struct
	* @nlba: Number of logical blocks exposed to the upper layers
	* after removing the amount of space needed by metadata
	* @rawsize: Total size in bytes of the available backing device
	* @lbasize: LBA size as requested and presented to upper layers.
	* This is sector_size + size of any metadata.
	* @sector_size: The Linux sector size - 512 or 4096
	* @lanes: Per-lane spinlocks
	* @init_lock: Mutex used for the BTT initialization
	* @init_state: Flag describing the initialization state for the BTT
	* @num_arenas: Number of arenas in the BTT instance
	* @phys_bb: Pointer to the namespace's badblocks structure
	*/
	struct btt {
	struct gendisk *btt_disk;
	struct request_queue *btt_queue;
	struct list_head arena_list;
	struct dentry *debugfs_dir;
	struct nd_btt *nd_btt;
	u64 nlba;
	unsigned long long rawsize;
	u32 lbasize;
	u32 sector_size;
	struct nd_region *nd_region;
	struct mutex init_lock;
	int init_state;
	int num_arenas;
	struct badblocks *phys_bb;
	};

	bool nd_btt_arena_is_valid(struct nd_btt nd_btt, struct btt_sb super);
	int nd_btt_version(struct nd_btt nd_btt, struct nd_namespace_common ndns,
	struct btt_sb *btt_sb);

	#endif