/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright 2023 Red Hat
*/
#ifndef VDO_H
#define VDO_H
#include <linux/atomic.h>
#include <linux/blk_types.h>
#include <linux/completion.h>
#include <linux/dm-kcopyd.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include "admin-state.h"
#include "encodings.h"
#include "funnel-workqueue.h"
#include "packer.h"
#include "physical-zone.h"
#include "statistics.h"
#include "thread-registry.h"
#include "types.h"
enum notifier_state {
/* Notifications are allowed but not in progress */
MAY_NOTIFY,
/* A notification is in progress */
NOTIFYING,
/* Notifications are not allowed */
MAY_NOT_NOTIFY,
/* A notification has completed */
NOTIFIED,
};
/**
* typedef vdo_read_only_notification_fn - A function to notify a listener that the VDO has gone
* read-only.
* @listener: The object to notify.
* @parent: The completion to notify in order to acknowledge the notification.
*/
typedef void (*vdo_read_only_notification_fn)(void *listener, struct vdo_completion *parent);
/*
* An object to be notified when the VDO enters read-only mode
*/
struct read_only_listener {
/* The listener */
void *listener;
/* The method to call to notify the listener */
vdo_read_only_notification_fn notify;
/* A pointer to the next listener */
struct read_only_listener *next;
};
struct vdo_thread {
struct vdo *vdo;
thread_id_t thread_id;
struct vdo_work_queue *queue;
/*
* Each thread maintains its own notion of whether the VDO is read-only so that the
* read-only state can be checked from any base thread without worrying about
* synchronization or thread safety. This does mean that knowledge of the VDO going
* read-only does not occur simultaneously across the VDO's threads, but that does not seem
* to cause any problems.
*/
bool is_read_only;
/*
* A list of objects waiting to be notified on this thread that the VDO has entered
* read-only mode.
*/
struct read_only_listener *listeners;
struct registered_thread allocating_thread;
};
/* Keep struct bio statistics atomically */
struct atomic_bio_stats {
atomic64_t read; /* Number of not REQ_WRITE bios */
atomic64_t write; /* Number of REQ_WRITE bios */
atomic64_t discard; /* Number of REQ_DISCARD bios */
atomic64_t flush; /* Number of REQ_FLUSH bios */
atomic64_t empty_flush; /* Number of REQ_PREFLUSH bios without data */
atomic64_t fua; /* Number of REQ_FUA bios */
};
/* Counters are atomic since updates can arrive concurrently from arbitrary threads. */
struct atomic_statistics {
atomic64_t bios_submitted;
atomic64_t bios_completed;
atomic64_t flush_out;
atomic64_t invalid_advice_pbn_count;
atomic64_t no_space_error_count;
atomic64_t read_only_error_count;
struct atomic_bio_stats bios_in;
struct atomic_bio_stats bios_in_partial;
struct atomic_bio_stats bios_out;
struct atomic_bio_stats bios_out_completed;
struct atomic_bio_stats bios_acknowledged;
struct atomic_bio_stats bios_acknowledged_partial;
struct atomic_bio_stats bios_meta;
struct atomic_bio_stats bios_meta_completed;
struct atomic_bio_stats bios_journal;
struct atomic_bio_stats bios_journal_completed;
struct atomic_bio_stats bios_page_cache;
struct atomic_bio_stats bios_page_cache_completed;
};
struct read_only_notifier {
/* The completion for entering read-only mode */
struct vdo_completion completion;
/* A completion waiting for notifications to be drained or enabled */
struct vdo_completion *waiter;
/* Lock to protect the next two fields */
spinlock_t lock;
/* The code of the error which put the VDO into read-only mode */
int read_only_error;
/* The current state of the notifier (values described above) */
enum notifier_state state;
};
/*
* The thread ID returned when the current thread is not a vdo thread, or can not be determined
* (usually due to being at interrupt context).
*/
#define VDO_INVALID_THREAD_ID ((thread_id_t) -1)
struct thread_config {
zone_count_t logical_zone_count;
zone_count_t physical_zone_count;
zone_count_t hash_zone_count;
thread_count_t bio_thread_count;
thread_count_t thread_count;
thread_id_t admin_thread;
thread_id_t journal_thread;
thread_id_t packer_thread;
thread_id_t dedupe_thread;
thread_id_t bio_ack_thread;
thread_id_t cpu_thread;
thread_id_t *logical_threads;
thread_id_t *physical_threads;
thread_id_t *hash_zone_threads;
thread_id_t *bio_threads;
};
struct thread_count_config;
struct vdo_super_block {
/* The vio for reading and writing the super block to disk */
struct vio vio;
/* A buffer to hold the super block */
u8 *buffer;
/* Whether this super block may not be written */
bool unwritable;
};
struct data_vio_pool;
struct vdo_administrator {
struct vdo_completion completion;
struct admin_state state;
atomic_t busy;
u32 phase;
struct completion callback_sync;
};
struct vdo {
char thread_name_prefix[MAX_VDO_WORK_QUEUE_NAME_LEN];
struct vdo_thread *threads;
vdo_action_fn action;
struct vdo_completion *completion;
struct vio_tracer *vio_tracer;
/* The atomic version of the state of this vdo */
atomic_t state;
/* The full state of all components */
struct vdo_component_states states;
/*
* A counter value to attach to thread names and log messages to identify the individual
* device.
*/
unsigned int instance;
/* The read-only notifier */
struct read_only_notifier read_only_notifier;
/* The load-time configuration of this vdo */
struct device_config *device_config;
/* The thread mapping */
struct thread_config thread_config;
/* The super block */
struct vdo_super_block super_block;
/* The partitioning of the underlying storage */
struct layout layout;
struct layout next_layout;
struct dm_kcopyd_client *partition_copier;
/* The block map */
struct block_map *block_map;
/* The journal for block map recovery */
struct recovery_journal *recovery_journal;
/* The slab depot */
struct slab_depot *depot;
/* The compressed-block packer */
struct packer *packer;
/* Whether incoming data should be compressed */
bool compressing;
/* The handler for flush requests */
struct flusher *flusher;
/* The state the vdo was in when loaded (primarily for unit tests) */
enum vdo_state load_state;
/* The logical zones of this vdo */
struct logical_zones *logical_zones;
/* The physical zones of this vdo */
struct physical_zones *physical_zones;
/* The hash lock zones of this vdo */
struct hash_zones *hash_zones;
/* Bio submission manager used for sending bios to the storage device. */
struct io_submitter *io_submitter;
/* The pool of data_vios for servicing incoming bios */
struct data_vio_pool *data_vio_pool;
/* The manager for administrative operations */
struct vdo_administrator admin;
/* Flags controlling administrative operations */
const struct admin_state_code *suspend_type;
bool allocations_allowed;
bool dump_on_shutdown;
atomic_t processing_message;
/*
* Statistics
* Atomic stats counters
*/
struct atomic_statistics stats;
/* Used to gather statistics without allocating memory */
struct vdo_statistics stats_buffer;
/* Protects the stats_buffer */
struct mutex stats_mutex;
/* A list of all device_configs referencing this vdo */
struct list_head device_config_list;
/* This VDO's list entry for the device registry */
struct list_head registration;
/* Underlying block device info. */
u64 starting_sector_offset;
struct volume_geometry geometry;
/* N blobs of context data for LZ4 code, one per CPU thread. */
char **compression_context;
};
/**
* vdo_uses_bio_ack_queue() - Indicate whether the vdo is configured to use a separate work queue
* for acknowledging received and processed bios.
* @vdo: The vdo.
*
* Note that this directly controls the handling of write operations, but the compile-time flag
* VDO_USE_BIO_ACK_QUEUE_FOR_READ is also checked for read operations.
*
* Return: Whether a bio-acknowledgement work queue is in use.
*/
static inline bool vdo_uses_bio_ack_queue(struct vdo *vdo)
{
return vdo->device_config->thread_counts.bio_ack_threads > 0;
}
/**
* typedef vdo_filter_fn - Method type for vdo matching methods.
*
* A filter function returns false if the vdo doesn't match.
*/
typedef bool (*vdo_filter_fn)(struct vdo *vdo, const void *context);
void vdo_initialize_device_registry_once(void);
struct vdo * __must_check vdo_find_matching(vdo_filter_fn filter, const void *context);
int __must_check vdo_make_thread(struct vdo *vdo, thread_id_t thread_id,
const struct vdo_work_queue_type *type,
unsigned int queue_count, void *contexts[]);
static inline int __must_check vdo_make_default_thread(struct vdo *vdo,
thread_id_t thread_id)
{
return vdo_make_thread(vdo, thread_id, NULL, 1, NULL);
}
int __must_check vdo_make(unsigned int instance, struct device_config *config,
char **reason, struct vdo **vdo_ptr);
void vdo_destroy(struct vdo *vdo);
void vdo_load_super_block(struct vdo *vdo, struct vdo_completion *parent);
struct block_device * __must_check vdo_get_backing_device(const struct vdo *vdo);
const char * __must_check vdo_get_device_name(const struct dm_target *target);
int __must_check vdo_synchronous_flush(struct vdo *vdo);
const struct admin_state_code * __must_check vdo_get_admin_state(const struct vdo *vdo);
bool vdo_set_compressing(struct vdo *vdo, bool enable);
bool vdo_get_compressing(struct vdo *vdo);
void vdo_fetch_statistics(struct vdo *vdo, struct vdo_statistics *stats);
thread_id_t vdo_get_callback_thread_id(void);
enum vdo_state __must_check vdo_get_state(const struct vdo *vdo);
void vdo_set_state(struct vdo *vdo, enum vdo_state state);
void vdo_save_components(struct vdo *vdo, struct vdo_completion *parent);
int vdo_register_read_only_listener(struct vdo *vdo, void *listener,
vdo_read_only_notification_fn notification,
thread_id_t thread_id);
int vdo_enable_read_only_entry(struct vdo *vdo);
void vdo_wait_until_not_entering_read_only_mode(struct vdo_completion *parent);
void vdo_allow_read_only_mode_entry(struct vdo_completion *parent);
void vdo_enter_read_only_mode(struct vdo *vdo, int error_code);
bool __must_check vdo_is_read_only(struct vdo *vdo);
bool __must_check vdo_in_read_only_mode(const struct vdo *vdo);
bool __must_check vdo_in_recovery_mode(const struct vdo *vdo);
void vdo_enter_recovery_mode(struct vdo *vdo);
void vdo_assert_on_admin_thread(const struct vdo *vdo, const char *name);
void vdo_assert_on_logical_zone_thread(const struct vdo *vdo, zone_count_t logical_zone,
const char *name);
void vdo_assert_on_physical_zone_thread(const struct vdo *vdo, zone_count_t physical_zone,
const char *name);
int __must_check vdo_get_physical_zone(const struct vdo *vdo, physical_block_number_t pbn,
struct physical_zone **zone_ptr);
void vdo_dump_status(const struct vdo *vdo);
#endif /* VDO_H */
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