drivers/nvdimm/btt.h

   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_GRP_SIZE sizeof(struct log_group)
  30 #define LOG_ENT_SIZE sizeof(struct log_entry)
  31 #define ARENA_MIN_SIZE (1UL << 24)      /* 16 MB */
  32 #define ARENA_MAX_SIZE (1ULL << 39)     /* 512 GB */
  33 #define RTT_VALID (1UL << 31)
  34 #define RTT_INVALID 0
  35 #define BTT_PG_SIZE 4096
  36 #define BTT_DEFAULT_NFREE ND_MAX_LANES
  37 #define LOG_SEQ_INIT 1
  38
  39 #define IB_FLAG_ERROR 0x00000001
  40 #define IB_FLAG_ERROR_MASK 0x00000001
  41
  42 enum 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
  85 struct log_entry {
  86         __le32 lba;
  87         __le32 old_map;
  88         __le32 new_map;
  89         __le32 seq;
  90 };
  91
  92 struct log_group {
  93         struct log_entry ent[4];
  94 };
  95
  96 struct 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
 118 struct free_entry {
 119         u32 block;
 120         u8 sub;
 121         u8 seq;
 122 };
 123
 124 struct aligned_lock {
 125         union {
 126                 spinlock_t lock;
 127                 u8 cacheline_padding[L1_CACHE_BYTES];
 128         };
 129 };
 130
 131 /**
 132  * struct arena_info - handle for an arena
 133  * @size:               Size in bytes this arena occupies on the raw device.
 134  *                      This includes arena metadata.
 135  * @external_lba_start: The first external LBA in this arena.
 136  * @internal_nlba:      Number of internal blocks available in the arena
 137  *                      including nfree reserved blocks
 138  * @internal_lbasize:   Internal and external lba sizes may be different as
 139  *                      we can round up 'odd' external lbasizes such as 520B
 140  *                      to be aligned.
 141  * @external_nlba:      Number of blocks contributed by the arena to the number
 142  *                      reported to upper layers. (internal_nlba - nfree)
 143  * @external_lbasize:   LBA size as exposed to upper layers.
 144  * @nfree:              A reserve number of 'free' blocks that is used to
 145  *                      handle incoming writes.
 146  * @version_major:      Metadata layout version major.
 147  * @version_minor:      Metadata layout version minor.
 148  * @nextoff:            Offset in bytes to the start of the next arena.
 149  * @infooff:            Offset in bytes to the info block of this arena.
 150  * @dataoff:            Offset in bytes to the data area of this arena.
 151  * @mapoff:             Offset in bytes to the map area of this arena.
 152  * @logoff:             Offset in bytes to the log area of this arena.
 153  * @info2off:           Offset in bytes to the backup info block of this arena.
 154  * @freelist:           Pointer to in-memory list of free blocks
 155  * @rtt:                Pointer to in-memory "Read Tracking Table"
 156  * @map_locks:          Spinlocks protecting concurrent map writes
 157  * @nd_btt:             Pointer to parent nd_btt structure.
 158  * @list:               List head for list of arenas
 159  * @debugfs_dir:        Debugfs dentry
 160  * @flags:              Arena flags - may signify error states.
 161  * @log_index:          Indices of the valid log entries in a log_group
 162  *
 163  * arena_info is a per-arena handle. Once an arena is narrowed down for an
 164  * IO, this struct is passed around for the duration of the IO.
 165  */
 166 struct arena_info {
 167         u64 size;                       /* Total bytes for this arena */
 168         u64 external_lba_start;
 169         u32 internal_nlba;
 170         u32 internal_lbasize;
 171         u32 external_nlba;
 172         u32 external_lbasize;
 173         u32 nfree;
 174         u16 version_major;
 175         u16 version_minor;
 176         /* Byte offsets to the different on-media structures */
 177         u64 nextoff;
 178         u64 infooff;
 179         u64 dataoff;
 180         u64 mapoff;
 181         u64 logoff;
 182         u64 info2off;
 183         /* Pointers to other in-memory structures for this arena */
 184         struct free_entry *freelist;
 185         u32 *rtt;
 186         struct aligned_lock *map_locks;
 187         struct nd_btt *nd_btt;
 188         struct list_head list;
 189         struct dentry *debugfs_dir;
 190         /* Arena flags */
 191         u32 flags;
 192         int log_index[2];
 193 };
 194
 195 /**
 196  * struct btt - handle for a BTT instance
 197  * @btt_disk:           Pointer to the gendisk for BTT device
 198  * @btt_queue:          Pointer to the request queue for the BTT device
 199  * @arena_list:         Head of the list of arenas
 200  * @debugfs_dir:        Debugfs dentry
 201  * @nd_btt:             Parent nd_btt struct
 202  * @nlba:               Number of logical blocks exposed to the upper layers
 203  *                      after removing the amount of space needed by metadata
 204  * @rawsize:            Total size in bytes of the available backing device
 205  * @lbasize:            LBA size as requested and presented to upper layers.
 206  *                      This is sector_size + size of any metadata.
 207  * @sector_size:        The Linux sector size - 512 or 4096
 208  * @lanes:              Per-lane spinlocks
 209  * @init_lock:          Mutex used for the BTT initialization
 210  * @init_state:         Flag describing the initialization state for the BTT
 211  * @num_arenas:         Number of arenas in the BTT instance
 212  */
 213 struct btt {
 214         struct gendisk *btt_disk;
 215         struct request_queue *btt_queue;
 216         struct list_head arena_list;
 217         struct dentry *debugfs_dir;
 218         struct nd_btt *nd_btt;
 219         u64 nlba;
 220         unsigned long long rawsize;
 221         u32 lbasize;
 222         u32 sector_size;
 223         struct nd_region *nd_region;
 224         struct mutex init_lock;
 225         int init_state;
 226         int num_arenas;
 227 };
 228
 229 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
 230
 231 #endif