1/*
  2 * Block Translation Table library
  3 * Copyright (c) 2014-2015, Intel Corporation.
  4 *
  5 * This program is free software; you can redistribute it and/or modify it
  6 * under the terms and conditions of the GNU General Public License,
  7 * version 2, as published by the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope it will be useful, but WITHOUT
 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 12 * more details.
 13 */
 14
 15#ifndef _LINUX_BTT_H
 16#define _LINUX_BTT_H
 17
 18#include <linux/types.h>
 19
 20#define BTT_SIG_LEN 16
 21#define BTT_SIG "BTT_ARENA_INFO\0"
 22#define MAP_ENT_SIZE 4
 23#define MAP_TRIM_SHIFT 31
 24#define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
 25#define MAP_ERR_SHIFT 30
 26#define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
 27#define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
 28#define MAP_ENT_NORMAL 0xC0000000
 29#define LOG_ENT_SIZE sizeof(struct log_entry)
 30#define ARENA_MIN_SIZE (1UL << 24)	/* 16 MB */
 31#define ARENA_MAX_SIZE (1ULL << 39)	/* 512 GB */
 32#define RTT_VALID (1UL << 31)
 33#define RTT_INVALID 0
 34#define BTT_PG_SIZE 4096
 35#define BTT_DEFAULT_NFREE ND_MAX_LANES
 36#define LOG_SEQ_INIT 1
 37
 38#define IB_FLAG_ERROR 0x00000001
 39#define IB_FLAG_ERROR_MASK 0x00000001
 40
 41enum btt_init_state {
 42	INIT_UNCHECKED = 0,
 43	INIT_NOTFOUND,
 44	INIT_READY
 45};
 46
 47struct log_entry {
 48	__le32 lba;
 49	__le32 old_map;
 50	__le32 new_map;
 51	__le32 seq;
 52	__le64 padding[2];
 53};
 54
 55struct btt_sb {
 56	u8 signature[BTT_SIG_LEN];
 57	u8 uuid[16];
 58	u8 parent_uuid[16];
 59	__le32 flags;
 60	__le16 version_major;
 61	__le16 version_minor;
 62	__le32 external_lbasize;
 63	__le32 external_nlba;
 64	__le32 internal_lbasize;
 65	__le32 internal_nlba;
 66	__le32 nfree;
 67	__le32 infosize;
 68	__le64 nextoff;
 69	__le64 dataoff;
 70	__le64 mapoff;
 71	__le64 logoff;
 72	__le64 info2off;
 73	u8 padding[3968];
 74	__le64 checksum;
 75};
 76
 77struct free_entry {
 78	u32 block;
 79	u8 sub;
 80	u8 seq;
 81};
 82
 83struct aligned_lock {
 84	union {
 85		spinlock_t lock;
 86		u8 cacheline_padding[L1_CACHE_BYTES];
 87	};
 88};
 89
 90/**
 91 * struct arena_info - handle for an arena
 92 * @size:		Size in bytes this arena occupies on the raw device.
 93 *			This includes arena metadata.
 94 * @external_lba_start:	The first external LBA in this arena.
 95 * @internal_nlba:	Number of internal blocks available in the arena
 96 *			including nfree reserved blocks
 97 * @internal_lbasize:	Internal and external lba sizes may be different as
 98 *			we can round up 'odd' external lbasizes such as 520B
 99 *			to be aligned.
100 * @external_nlba:	Number of blocks contributed by the arena to the number
101 *			reported to upper layers. (internal_nlba - nfree)
102 * @external_lbasize:	LBA size as exposed to upper layers.
103 * @nfree:		A reserve number of 'free' blocks that is used to
104 *			handle incoming writes.
105 * @version_major:	Metadata layout version major.
106 * @version_minor:	Metadata layout version minor.
107 * @nextoff:		Offset in bytes to the start of the next arena.
108 * @infooff:		Offset in bytes to the info block of this arena.
109 * @dataoff:		Offset in bytes to the data area of this arena.
110 * @mapoff:		Offset in bytes to the map area of this arena.
111 * @logoff:		Offset in bytes to the log area of this arena.
112 * @info2off:		Offset in bytes to the backup info block of this arena.
113 * @freelist:		Pointer to in-memory list of free blocks
114 * @rtt:		Pointer to in-memory "Read Tracking Table"
115 * @map_locks:		Spinlocks protecting concurrent map writes
116 * @nd_btt:		Pointer to parent nd_btt structure.
117 * @list:		List head for list of arenas
118 * @debugfs_dir:	Debugfs dentry
119 * @flags:		Arena flags - may signify error states.
120 *
121 * arena_info is a per-arena handle. Once an arena is narrowed down for an
122 * IO, this struct is passed around for the duration of the IO.
123 */
124struct arena_info {
125	u64 size;			/* Total bytes for this arena */
126	u64 external_lba_start;
127	u32 internal_nlba;
128	u32 internal_lbasize;
129	u32 external_nlba;
130	u32 external_lbasize;
131	u32 nfree;
132	u16 version_major;
133	u16 version_minor;
134	/* Byte offsets to the different on-media structures */
135	u64 nextoff;
136	u64 infooff;
137	u64 dataoff;
138	u64 mapoff;
139	u64 logoff;
140	u64 info2off;
141	/* Pointers to other in-memory structures for this arena */
142	struct free_entry *freelist;
143	u32 *rtt;
144	struct aligned_lock *map_locks;
145	struct nd_btt *nd_btt;
146	struct list_head list;
147	struct dentry *debugfs_dir;
148	/* Arena flags */
149	u32 flags;
150};
151
152/**
153 * struct btt - handle for a BTT instance
154 * @btt_disk:		Pointer to the gendisk for BTT device
155 * @btt_queue:		Pointer to the request queue for the BTT device
156 * @arena_list:		Head of the list of arenas
157 * @debugfs_dir:	Debugfs dentry
158 * @nd_btt:		Parent nd_btt struct
159 * @nlba:		Number of logical blocks exposed to the	upper layers
160 *			after removing the amount of space needed by metadata
161 * @rawsize:		Total size in bytes of the available backing device
162 * @lbasize:		LBA size as requested and presented to upper layers.
163 *			This is sector_size + size of any metadata.
164 * @sector_size:	The Linux sector size - 512 or 4096
165 * @lanes:		Per-lane spinlocks
166 * @init_lock:		Mutex used for the BTT initialization
167 * @init_state:		Flag describing the initialization state for the BTT
168 * @num_arenas:		Number of arenas in the BTT instance
169 */
170struct btt {
171	struct gendisk *btt_disk;
172	struct request_queue *btt_queue;
173	struct list_head arena_list;
174	struct dentry *debugfs_dir;
175	struct nd_btt *nd_btt;
176	u64 nlba;
177	unsigned long long rawsize;
178	u32 lbasize;
179	u32 sector_size;
180	struct nd_region *nd_region;
181	struct mutex init_lock;
182	int init_state;
183	int num_arenas;
184};
185
186bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
187
188#endif