247 lines
7.6 KiB
C
247 lines
7.6 KiB
C
/*
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* Block Translation Table library
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* Copyright (c) 2014-2015, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#ifndef _LINUX_BTT_H
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#define _LINUX_BTT_H
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#include <linux/badblocks.h>
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#include <linux/types.h>
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#define BTT_SIG_LEN 16
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#define BTT_SIG "BTT_ARENA_INFO\0"
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#define MAP_ENT_SIZE 4
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#define MAP_TRIM_SHIFT 31
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#define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
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#define MAP_ERR_SHIFT 30
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#define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
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#define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
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#define MAP_ENT_NORMAL 0xC0000000
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#define LOG_GRP_SIZE sizeof(struct log_group)
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#define LOG_ENT_SIZE sizeof(struct log_entry)
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#define ARENA_MIN_SIZE (1UL << 24) /* 16 MB */
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#define ARENA_MAX_SIZE (1ULL << 39) /* 512 GB */
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#define RTT_VALID (1UL << 31)
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#define RTT_INVALID 0
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#define BTT_PG_SIZE 4096
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#define BTT_DEFAULT_NFREE ND_MAX_LANES
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#define LOG_SEQ_INIT 1
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#define IB_FLAG_ERROR 0x00000001
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#define IB_FLAG_ERROR_MASK 0x00000001
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#define ent_lba(ent) (ent & MAP_LBA_MASK)
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#define ent_e_flag(ent) (!!(ent & MAP_ERR_MASK))
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#define ent_z_flag(ent) (!!(ent & MAP_TRIM_MASK))
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#define set_e_flag(ent) (ent |= MAP_ERR_MASK)
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enum btt_init_state {
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INIT_UNCHECKED = 0,
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INIT_NOTFOUND,
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INIT_READY
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};
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/*
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* A log group represents one log 'lane', and consists of four log entries.
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* Two of the four entries are valid entries, and the remaining two are
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* padding. Due to an old bug in the padding location, we need to perform a
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* test to determine the padding scheme being used, and use that scheme
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* thereafter.
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*
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* In kernels prior to 4.15, 'log group' would have actual log entries at
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* indices (0, 2) and padding at indices (1, 3), where as the correct/updated
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* format has log entries at indices (0, 1) and padding at indices (2, 3).
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*
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* Old (pre 4.15) format:
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* +-----------------+-----------------+
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* | ent[0] | ent[1] |
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* | 16B | 16B |
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* | lba/old/new/seq | pad |
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* +-----------------------------------+
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* | ent[2] | ent[3] |
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* | 16B | 16B |
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* | lba/old/new/seq | pad |
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* +-----------------+-----------------+
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*
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* New format:
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* +-----------------+-----------------+
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* | ent[0] | ent[1] |
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* | 16B | 16B |
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* | lba/old/new/seq | lba/old/new/seq |
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* +-----------------------------------+
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* | ent[2] | ent[3] |
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* | 16B | 16B |
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* | pad | pad |
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* +-----------------+-----------------+
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*
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* We detect during start-up which format is in use, and set
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* arena->log_index[(0, 1)] with the detected format.
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*/
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struct log_entry {
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__le32 lba;
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__le32 old_map;
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__le32 new_map;
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__le32 seq;
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};
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struct log_group {
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struct log_entry ent[4];
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};
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struct btt_sb {
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u8 signature[BTT_SIG_LEN];
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u8 uuid[16];
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u8 parent_uuid[16];
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__le32 flags;
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__le16 version_major;
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__le16 version_minor;
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__le32 external_lbasize;
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__le32 external_nlba;
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__le32 internal_lbasize;
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__le32 internal_nlba;
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__le32 nfree;
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__le32 infosize;
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__le64 nextoff;
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__le64 dataoff;
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__le64 mapoff;
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__le64 logoff;
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__le64 info2off;
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u8 padding[3968];
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__le64 checksum;
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};
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struct free_entry {
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u32 block;
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u8 sub;
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u8 seq;
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u8 has_err;
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};
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struct aligned_lock {
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union {
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spinlock_t lock;
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u8 cacheline_padding[L1_CACHE_BYTES];
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};
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};
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/**
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* struct arena_info - handle for an arena
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* @size: Size in bytes this arena occupies on the raw device.
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* This includes arena metadata.
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* @external_lba_start: The first external LBA in this arena.
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* @internal_nlba: Number of internal blocks available in the arena
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* including nfree reserved blocks
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* @internal_lbasize: Internal and external lba sizes may be different as
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* we can round up 'odd' external lbasizes such as 520B
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* to be aligned.
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* @external_nlba: Number of blocks contributed by the arena to the number
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* reported to upper layers. (internal_nlba - nfree)
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* @external_lbasize: LBA size as exposed to upper layers.
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* @nfree: A reserve number of 'free' blocks that is used to
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* handle incoming writes.
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* @version_major: Metadata layout version major.
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* @version_minor: Metadata layout version minor.
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* @sector_size: The Linux sector size - 512 or 4096
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* @nextoff: Offset in bytes to the start of the next arena.
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* @infooff: Offset in bytes to the info block of this arena.
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* @dataoff: Offset in bytes to the data area of this arena.
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* @mapoff: Offset in bytes to the map area of this arena.
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* @logoff: Offset in bytes to the log area of this arena.
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* @info2off: Offset in bytes to the backup info block of this arena.
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* @freelist: Pointer to in-memory list of free blocks
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* @rtt: Pointer to in-memory "Read Tracking Table"
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* @map_locks: Spinlocks protecting concurrent map writes
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* @nd_btt: Pointer to parent nd_btt structure.
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* @list: List head for list of arenas
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* @debugfs_dir: Debugfs dentry
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* @flags: Arena flags - may signify error states.
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* @err_lock: Mutex for synchronizing error clearing.
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* @log_index: Indices of the valid log entries in a log_group
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*
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* arena_info is a per-arena handle. Once an arena is narrowed down for an
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* IO, this struct is passed around for the duration of the IO.
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*/
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struct arena_info {
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u64 size; /* Total bytes for this arena */
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u64 external_lba_start;
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u32 internal_nlba;
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u32 internal_lbasize;
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u32 external_nlba;
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u32 external_lbasize;
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u32 nfree;
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u16 version_major;
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u16 version_minor;
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u32 sector_size;
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/* Byte offsets to the different on-media structures */
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u64 nextoff;
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u64 infooff;
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u64 dataoff;
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u64 mapoff;
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u64 logoff;
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u64 info2off;
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/* Pointers to other in-memory structures for this arena */
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struct free_entry *freelist;
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u32 *rtt;
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struct aligned_lock *map_locks;
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struct nd_btt *nd_btt;
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struct list_head list;
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struct dentry *debugfs_dir;
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/* Arena flags */
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u32 flags;
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struct mutex err_lock;
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int log_index[2];
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};
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/**
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* struct btt - handle for a BTT instance
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* @btt_disk: Pointer to the gendisk for BTT device
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* @btt_queue: Pointer to the request queue for the BTT device
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* @arena_list: Head of the list of arenas
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* @debugfs_dir: Debugfs dentry
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* @nd_btt: Parent nd_btt struct
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* @nlba: Number of logical blocks exposed to the upper layers
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* after removing the amount of space needed by metadata
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* @rawsize: Total size in bytes of the available backing device
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* @lbasize: LBA size as requested and presented to upper layers.
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* This is sector_size + size of any metadata.
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* @sector_size: The Linux sector size - 512 or 4096
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* @lanes: Per-lane spinlocks
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* @init_lock: Mutex used for the BTT initialization
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* @init_state: Flag describing the initialization state for the BTT
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* @num_arenas: Number of arenas in the BTT instance
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* @phys_bb: Pointer to the namespace's badblocks structure
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*/
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struct btt {
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struct gendisk *btt_disk;
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struct request_queue *btt_queue;
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struct list_head arena_list;
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struct dentry *debugfs_dir;
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struct nd_btt *nd_btt;
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u64 nlba;
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unsigned long long rawsize;
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u32 lbasize;
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u32 sector_size;
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struct nd_region *nd_region;
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struct mutex init_lock;
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int init_state;
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int num_arenas;
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struct badblocks *phys_bb;
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};
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bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
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int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
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struct btt_sb *btt_sb);
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#endif
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