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/*
* 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)
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
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