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/badblocks.h>
  19 #include <linux/types.h>
  20
  21 #define BTT_SIG_LEN 16
  22 #define BTT_SIG "BTT_ARENA_INFO\0"
  23 #define MAP_ENT_SIZE 4
  24 #define MAP_TRIM_SHIFT 31
  25 #define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
  26 #define MAP_ERR_SHIFT 30
  27 #define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
  28 #define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
  29 #define MAP_ENT_NORMAL 0xC0000000
  30 #define LOG_GRP_SIZE sizeof(struct log_group)
  31 #define LOG_ENT_SIZE sizeof(struct log_entry)
  32 #define ARENA_MIN_SIZE (1UL << 24)      /* 16 MB */
  33 #define ARENA_MAX_SIZE (1ULL << 39)     /* 512 GB */
  34 #define RTT_VALID (1UL << 31)
  35 #define RTT_INVALID 0
  36 #define BTT_PG_SIZE 4096
  37 #define BTT_DEFAULT_NFREE ND_MAX_LANES
  38 #define LOG_SEQ_INIT 1
  39
  40 #define IB_FLAG_ERROR 0x00000001
  41 #define IB_FLAG_ERROR_MASK 0x00000001
  42
  43 #define ent_lba(ent) (ent & MAP_LBA_MASK)
  44 #define ent_e_flag(ent) (!!(ent & MAP_ERR_MASK))
  45 #define ent_z_flag(ent) (!!(ent & MAP_TRIM_MASK))
  46 #define set_e_flag(ent) (ent |= MAP_ERR_MASK)
  47
  48 enum btt_init_state {
  49         INIT_UNCHECKED = 0,
  50         INIT_NOTFOUND,
  51         INIT_READY
  52 };
  53
  54 /*
  55  * A log group represents one log 'lane', and consists of four log entries.
  56  * Two of the four entries are valid entries, and the remaining two are
  57  * padding. Due to an old bug in the padding location, we need to perform a
  58  * test to determine the padding scheme being used, and use that scheme
  59  * thereafter.
  60  *
  61  * In kernels prior to 4.15, 'log group' would have actual log entries at
  62  * indices (0, 2) and padding at indices (1, 3), where as the correct/updated
  63  * format has log entries at indices (0, 1) and padding at indices (2, 3).
  64  *
  65  * Old (pre 4.15) format:
  66  * +-----------------+-----------------+
  67  * |      ent[0]     |      ent[1]     |
  68  * |       16B       |       16B       |
  69  * | lba/old/new/seq |       pad       |
  70  * +-----------------------------------+
  71  * |      ent[2]     |      ent[3]     |
  72  * |       16B       |       16B       |
  73  * | lba/old/new/seq |       pad       |
  74  * +-----------------+-----------------+
  75  *
  76  * New format:
  77  * +-----------------+-----------------+
  78  * |      ent[0]     |      ent[1]     |
  79  * |       16B       |       16B       |
  80  * | lba/old/new/seq | lba/old/new/seq |
  81  * +-----------------------------------+
  82  * |      ent[2]     |      ent[3]     |
  83  * |       16B       |       16B       |
  84  * |       pad       |       pad       |
  85  * +-----------------+-----------------+
  86  *
  87  * We detect during start-up which format is in use, and set
  88  * arena->log_index[(0, 1)] with the detected format.
  89  */
  90
  91 struct log_entry {
  92         __le32 lba;
  93         __le32 old_map;
  94         __le32 new_map;
  95         __le32 seq;
  96 };
  97
  98 struct log_group {
  99         struct log_entry ent[4];
 100 };
 101
 102 struct btt_sb {
 103         u8 signature[BTT_SIG_LEN];
 104         u8 uuid[16];
 105         u8 parent_uuid[16];
 106         __le32 flags;
 107         __le16 version_major;
 108         __le16 version_minor;
 109         __le32 external_lbasize;
 110         __le32 external_nlba;
 111         __le32 internal_lbasize;
 112         __le32 internal_nlba;
 113         __le32 nfree;
 114         __le32 infosize;
 115         __le64 nextoff;
 116         __le64 dataoff;
 117         __le64 mapoff;
 118         __le64 logoff;
 119         __le64 info2off;
 120         u8 padding[3968];
 121         __le64 checksum;
 122 };
 123
 124 struct free_entry {
 125         u32 block;
 126         u8 sub;
 127         u8 seq;
 128         u8 has_err;
 129 };
 130
 131 struct aligned_lock {
 132         union {
 133                 spinlock_t lock;
 134                 u8 cacheline_padding[L1_CACHE_BYTES];
 135         };
 136 };
 137
 138 /**
 139  * struct arena_info - handle for an arena
 140  * @size:               Size in bytes this arena occupies on the raw device.
 141  *                      This includes arena metadata.
 142  * @external_lba_start: The first external LBA in this arena.
 143  * @internal_nlba:      Number of internal blocks available in the arena
 144  *                      including nfree reserved blocks
 145  * @internal_lbasize:   Internal and external lba sizes may be different as
 146  *                      we can round up 'odd' external lbasizes such as 520B
 147  *                      to be aligned.
 148  * @external_nlba:      Number of blocks contributed by the arena to the number
 149  *                      reported to upper layers. (internal_nlba - nfree)
 150  * @external_lbasize:   LBA size as exposed to upper layers.
 151  * @nfree:              A reserve number of 'free' blocks that is used to
 152  *                      handle incoming writes.
 153  * @version_major:      Metadata layout version major.
 154  * @version_minor:      Metadata layout version minor.
 155  * @sector_size:        The Linux sector size - 512 or 4096
 156  * @nextoff:            Offset in bytes to the start of the next arena.
 157  * @infooff:            Offset in bytes to the info block of this arena.
 158  * @dataoff:            Offset in bytes to the data area of this arena.
 159  * @mapoff:             Offset in bytes to the map area of this arena.
 160  * @logoff:             Offset in bytes to the log area of this arena.
 161  * @info2off:           Offset in bytes to the backup info block of this arena.
 162  * @freelist:           Pointer to in-memory list of free blocks
 163  * @rtt:                Pointer to in-memory "Read Tracking Table"
 164  * @map_locks:          Spinlocks protecting concurrent map writes
 165  * @nd_btt:             Pointer to parent nd_btt structure.
 166  * @list:               List head for list of arenas
 167  * @debugfs_dir:        Debugfs dentry
 168  * @flags:              Arena flags - may signify error states.
 169  * @err_lock:           Mutex for synchronizing error clearing.
 170  * @log_index:          Indices of the valid log entries in a log_group
 171  *
 172  * arena_info is a per-arena handle. Once an arena is narrowed down for an
 173  * IO, this struct is passed around for the duration of the IO.
 174  */
 175 struct arena_info {
 176         u64 size;                       /* Total bytes for this arena */
 177         u64 external_lba_start;
 178         u32 internal_nlba;
 179         u32 internal_lbasize;
 180         u32 external_nlba;
 181         u32 external_lbasize;
 182         u32 nfree;
 183         u16 version_major;
 184         u16 version_minor;
 185         u32 sector_size;
 186         /* Byte offsets to the different on-media structures */
 187         u64 nextoff;
 188         u64 infooff;
 189         u64 dataoff;
 190         u64 mapoff;
 191         u64 logoff;
 192         u64 info2off;
 193         /* Pointers to other in-memory structures for this arena */
 194         struct free_entry *freelist;
 195         u32 *rtt;
 196         struct aligned_lock *map_locks;
 197         struct nd_btt *nd_btt;
 198         struct list_head list;
 199         struct dentry *debugfs_dir;
 200         /* Arena flags */
 201         u32 flags;
 202         struct mutex err_lock;
 203         int log_index[2];
 204 };
 205
 206 /**
 207  * struct btt - handle for a BTT instance
 208  * @btt_disk:           Pointer to the gendisk for BTT device
 209  * @btt_queue:          Pointer to the request queue for the BTT device
 210  * @arena_list:         Head of the list of arenas
 211  * @debugfs_dir:        Debugfs dentry
 212  * @nd_btt:             Parent nd_btt struct
 213  * @nlba:               Number of logical blocks exposed to the upper layers
 214  *                      after removing the amount of space needed by metadata
 215  * @rawsize:            Total size in bytes of the available backing device
 216  * @lbasize:            LBA size as requested and presented to upper layers.
 217  *                      This is sector_size + size of any metadata.
 218  * @sector_size:        The Linux sector size - 512 or 4096
 219  * @lanes:              Per-lane spinlocks
 220  * @init_lock:          Mutex used for the BTT initialization
 221  * @init_state:         Flag describing the initialization state for the BTT
 222  * @num_arenas:         Number of arenas in the BTT instance
 223  * @phys_bb:            Pointer to the namespace's badblocks structure
 224  */
 225 struct btt {
 226         struct gendisk *btt_disk;
 227         struct request_queue *btt_queue;
 228         struct list_head arena_list;
 229         struct dentry *debugfs_dir;
 230         struct nd_btt *nd_btt;
 231         u64 nlba;
 232         unsigned long long rawsize;
 233         u32 lbasize;
 234         u32 sector_size;
 235         struct nd_region *nd_region;
 236         struct mutex init_lock;
 237         int init_state;
 238         int num_arenas;
 239         struct badblocks *phys_bb;
 240 };
 241
 242 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
 243 int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
 244                 struct btt_sb *btt_sb);
 245
 246 #endif