1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Block Translation Table library
  4 * Copyright (c) 2014-2015, Intel Corporation.
  5 */
  6
  7#ifndef _LINUX_BTT_H
  8#define _LINUX_BTT_H
  9
 10#include <linux/badblocks.h>
 11#include <linux/types.h>
 12
 13#define BTT_SIG_LEN 16
 14#define BTT_SIG "BTT_ARENA_INFO\0"
 15#define MAP_ENT_SIZE 4
 16#define MAP_TRIM_SHIFT 31
 17#define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
 18#define MAP_ERR_SHIFT 30
 19#define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
 20#define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
 21#define MAP_ENT_NORMAL 0xC0000000
 22#define LOG_GRP_SIZE sizeof(struct log_group)
 23#define LOG_ENT_SIZE sizeof(struct log_entry)
 24#define ARENA_MIN_SIZE (1UL << 24)	/* 16 MB */
 25#define ARENA_MAX_SIZE (1ULL << 39)	/* 512 GB */
 26#define RTT_VALID (1UL << 31)
 27#define RTT_INVALID 0
 28#define BTT_PG_SIZE 4096
 29#define BTT_DEFAULT_NFREE ND_MAX_LANES
 30#define LOG_SEQ_INIT 1
 31
 32#define IB_FLAG_ERROR 0x00000001
 33#define IB_FLAG_ERROR_MASK 0x00000001
 34
 35#define ent_lba(ent) (ent & MAP_LBA_MASK)
 36#define ent_e_flag(ent) (!!(ent & MAP_ERR_MASK))
 37#define ent_z_flag(ent) (!!(ent & MAP_TRIM_MASK))
 38#define set_e_flag(ent) (ent |= MAP_ERR_MASK)
 39/* 'normal' is both e and z flags set */
 40#define ent_normal(ent) (ent_e_flag(ent) && ent_z_flag(ent))
 41
 42enum btt_init_state {
 43	INIT_UNCHECKED = 0,
 44	INIT_NOTFOUND,
 45	INIT_READY
 46};
 47
 48/*
 49 * A log group represents one log 'lane', and consists of four log entries.
 50 * Two of the four entries are valid entries, and the remaining two are
 51 * padding. Due to an old bug in the padding location, we need to perform a
 52 * test to determine the padding scheme being used, and use that scheme
 53 * thereafter.
 54 *
 55 * In kernels prior to 4.15, 'log group' would have actual log entries at
 56 * indices (0, 2) and padding at indices (1, 3), where as the correct/updated
 57 * format has log entries at indices (0, 1) and padding at indices (2, 3).
 58 *
 59 * Old (pre 4.15) format:
 60 * +-----------------+-----------------+
 61 * |      ent[0]     |      ent[1]     |
 62 * |       16B       |       16B       |
 63 * | lba/old/new/seq |       pad       |
 64 * +-----------------------------------+
 65 * |      ent[2]     |      ent[3]     |
 66 * |       16B       |       16B       |
 67 * | lba/old/new/seq |       pad       |
 68 * +-----------------+-----------------+
 69 *
 70 * New format:
 71 * +-----------------+-----------------+
 72 * |      ent[0]     |      ent[1]     |
 73 * |       16B       |       16B       |
 74 * | lba/old/new/seq | lba/old/new/seq |
 75 * +-----------------------------------+
 76 * |      ent[2]     |      ent[3]     |
 77 * |       16B       |       16B       |
 78 * |       pad       |       pad       |
 79 * +-----------------+-----------------+
 80 *
 81 * We detect during start-up which format is in use, and set
 82 * arena->log_index[(0, 1)] with the detected format.
 83 */
 84
 85struct log_entry {
 86	__le32 lba;
 87	__le32 old_map;
 88	__le32 new_map;
 89	__le32 seq;
 90};
 91
 92struct log_group {
 93	struct log_entry ent[4];
 94};
 95
 96struct btt_sb {
 97	u8 signature[BTT_SIG_LEN];
 98	u8 uuid[16];
 99	u8 parent_uuid[16];
100	__le32 flags;
101	__le16 version_major;
102	__le16 version_minor;
103	__le32 external_lbasize;
104	__le32 external_nlba;
105	__le32 internal_lbasize;
106	__le32 internal_nlba;
107	__le32 nfree;
108	__le32 infosize;
109	__le64 nextoff;
110	__le64 dataoff;
111	__le64 mapoff;
112	__le64 logoff;
113	__le64 info2off;
114	u8 padding[3968];
115	__le64 checksum;
116};
117
118struct free_entry {
119	u32 block;
120	u8 sub;
121	u8 seq;
122	u8 has_err;
123};
124
125struct aligned_lock {
126	union {
127		spinlock_t lock;
128		u8 cacheline_padding[L1_CACHE_BYTES];
129	};
130};
131
132/**
133 * struct arena_info - handle for an arena
134 * @size:		Size in bytes this arena occupies on the raw device.
135 *			This includes arena metadata.
136 * @external_lba_start:	The first external LBA in this arena.
137 * @internal_nlba:	Number of internal blocks available in the arena
138 *			including nfree reserved blocks
139 * @internal_lbasize:	Internal and external lba sizes may be different as
140 *			we can round up 'odd' external lbasizes such as 520B
141 *			to be aligned.
142 * @external_nlba:	Number of blocks contributed by the arena to the number
143 *			reported to upper layers. (internal_nlba - nfree)
144 * @external_lbasize:	LBA size as exposed to upper layers.
145 * @nfree:		A reserve number of 'free' blocks that is used to
146 *			handle incoming writes.
147 * @version_major:	Metadata layout version major.
148 * @version_minor:	Metadata layout version minor.
149 * @sector_size:	The Linux sector size - 512 or 4096
150 * @nextoff:		Offset in bytes to the start of the next arena.
151 * @infooff:		Offset in bytes to the info block of this arena.
152 * @dataoff:		Offset in bytes to the data area of this arena.
153 * @mapoff:		Offset in bytes to the map area of this arena.
154 * @logoff:		Offset in bytes to the log area of this arena.
155 * @info2off:		Offset in bytes to the backup info block of this arena.
156 * @freelist:		Pointer to in-memory list of free blocks
157 * @rtt:		Pointer to in-memory "Read Tracking Table"
158 * @map_locks:		Spinlocks protecting concurrent map writes
159 * @nd_btt:		Pointer to parent nd_btt structure.
160 * @list:		List head for list of arenas
161 * @debugfs_dir:	Debugfs dentry
162 * @flags:		Arena flags - may signify error states.
163 * @err_lock:		Mutex for synchronizing error clearing.
164 * @log_index:		Indices of the valid log entries in a log_group
165 *
166 * arena_info is a per-arena handle. Once an arena is narrowed down for an
167 * IO, this struct is passed around for the duration of the IO.
168 */
169struct arena_info {
170	u64 size;			/* Total bytes for this arena */
171	u64 external_lba_start;
172	u32 internal_nlba;
173	u32 internal_lbasize;
174	u32 external_nlba;
175	u32 external_lbasize;
176	u32 nfree;
177	u16 version_major;
178	u16 version_minor;
179	u32 sector_size;
180	/* Byte offsets to the different on-media structures */
181	u64 nextoff;
182	u64 infooff;
183	u64 dataoff;
184	u64 mapoff;
185	u64 logoff;
186	u64 info2off;
187	/* Pointers to other in-memory structures for this arena */
188	struct free_entry *freelist;
189	u32 *rtt;
190	struct aligned_lock *map_locks;
191	struct nd_btt *nd_btt;
192	struct list_head list;
193	struct dentry *debugfs_dir;
194	/* Arena flags */
195	u32 flags;
196	struct mutex err_lock;
197	int log_index[2];
198};
199
200/**
201 * struct btt - handle for a BTT instance
202 * @btt_disk:		Pointer to the gendisk for BTT device
203 * @btt_queue:		Pointer to the request queue for the BTT device
204 * @arena_list:		Head of the list of arenas
205 * @debugfs_dir:	Debugfs dentry
206 * @nd_btt:		Parent nd_btt struct
207 * @nlba:		Number of logical blocks exposed to the	upper layers
208 *			after removing the amount of space needed by metadata
209 * @rawsize:		Total size in bytes of the available backing device
210 * @lbasize:		LBA size as requested and presented to upper layers.
211 *			This is sector_size + size of any metadata.
212 * @sector_size:	The Linux sector size - 512 or 4096
213 * @lanes:		Per-lane spinlocks
214 * @init_lock:		Mutex used for the BTT initialization
215 * @init_state:		Flag describing the initialization state for the BTT
216 * @num_arenas:		Number of arenas in the BTT instance
217 * @phys_bb:		Pointer to the namespace's badblocks structure
218 */
219struct btt {
220	struct gendisk *btt_disk;
221	struct request_queue *btt_queue;
222	struct list_head arena_list;
223	struct dentry *debugfs_dir;
224	struct nd_btt *nd_btt;
225	u64 nlba;
226	unsigned long long rawsize;
227	u32 lbasize;
228	u32 sector_size;
229	struct nd_region *nd_region;
230	struct mutex init_lock;
231	int init_state;
232	int num_arenas;
233	struct badblocks *phys_bb;
234};
235
236bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
237int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
238		struct btt_sb *btt_sb);
239
240#endif