zfs/include/sys/zvol_impl.h

// SPDX-License-Identifier: CDDL-1.0
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or https://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2024, 2025, Klara, Inc.
 */

#ifndef	_SYS_ZVOL_IMPL_H
#define	_SYS_ZVOL_IMPL_H

#include <sys/zfs_context.h>

#define	ZVOL_RDONLY	(1<<0)	/* zvol is readonly (writes rejected) */
#define	ZVOL_WRITTEN_TO	(1<<1)	/* zvol has been written to (needs flush) */
#define	ZVOL_EXCL	(1<<2)	/* zvol has O_EXCL client right now */
#define	ZVOL_REMOVING	(1<<3)	/* zvol waiting to remove minor */

/*
 * The in-core state of each volume.
 */
typedef struct zvol_state {
	char			zv_name[MAXNAMELEN];	/* name */
	uint64_t		zv_volsize;		/* advertised space */
	uint64_t		zv_volblocksize;	/* volume block size */
	objset_t		*zv_objset;	/* objset handle */
	uint32_t		zv_flags;	/* ZVOL_* flags */
	uint32_t		zv_open_count;	/* open counts */
	uint32_t		zv_changed;	/* disk changed */
	uint32_t		zv_volmode;	/* volmode */
	zilog_t			*zv_zilog;	/* ZIL handle */
	zfs_rangelock_t		zv_rangelock;	/* for range locking */
	dnode_t			*zv_dn;		/* dnode hold */
	dataset_kstats_t	zv_kstat;	/* zvol kstats */
	list_node_t		zv_next;	/* next zvol_state_t linkage */
	uint64_t		zv_hash;	/* name hash */
	struct hlist_node	zv_hlink;	/* hash link */
	kmutex_t		zv_state_lock;	/* protects zvol_state_t */
	atomic_t		zv_suspend_ref;	/* refcount for suspend */
	krwlock_t		zv_suspend_lock;	/* suspend lock */
	kcondvar_t		zv_removing_cv;	/* ready to remove minor */
	list_node_t		zv_remove_node;	/* node on removal list */
	struct zvol_state_os	*zv_zso;	/* private platform state */
	boolean_t		zv_threading;	/* volthreading property */
} zvol_state_t;

/*
 * zvol taskqs
 */
typedef struct zv_taskq {
	uint_t tqs_cnt;
	taskq_t **tqs_taskq;
} zv_taskq_t;

typedef struct zv_request_stack {
	zvol_state_t	*zv;
	struct bio	*bio;
#ifdef __linux__
	struct request	*rq;
#endif
} zv_request_t;

typedef struct zv_request_task {
	zv_request_t	zvr;
	taskq_ent_t	ent;
} zv_request_task_t;

/*
 * Switch taskq at multiple of 512 MB offset. This can be set to a lower value
 * to utilize more threads for small files but may affect prefetch hits.
 */
#define	ZVOL_TASKQ_OFFSET_SHIFT 29

extern krwlock_t zvol_state_lock;
#define	ZVOL_HT_SIZE	1024
extern struct hlist_head *zvol_htable;
#define	ZVOL_HT_HEAD(hash)	(&zvol_htable[(hash) & (ZVOL_HT_SIZE-1)])
extern zil_replay_func_t *const zvol_replay_vector[TX_MAX_TYPE];

extern unsigned int zvol_inhibit_dev;
extern unsigned int zvol_prefetch_bytes;
extern unsigned int zvol_volmode;
extern unsigned int zvol_threads;
extern unsigned int zvol_num_taskqs;
extern unsigned int zvol_request_sync;
extern zv_taskq_t zvol_taskqs;

/*
 * platform independent functions exported to platform code
 */
zvol_state_t *zvol_find_by_name_hash(const char *name,
    uint64_t hash, int mode);
int zvol_first_open(zvol_state_t *zv, boolean_t readonly);
uint64_t zvol_name_hash(const char *name);
void zvol_last_close(zvol_state_t *zv);
void zvol_insert(zvol_state_t *zv);
void zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off,
    uint64_t len);
void zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, uint64_t offset,
    uint64_t size, boolean_t commit);
int zvol_get_data(void *arg, uint64_t arg2, lr_write_t *lr, char *buf,
    struct lwb *lwb, zio_t *zio);
int zvol_init_impl(void);
void zvol_fini_impl(void);
void zvol_wait_close(zvol_state_t *zv);
int zvol_clone_range(zvol_state_handle_t *, uint64_t,
    zvol_state_handle_t *, uint64_t, uint64_t);
void zvol_log_clone_range(zilog_t *zilog, dmu_tx_t *tx, int txtype,
    uint64_t off, uint64_t len, uint64_t blksz, const blkptr_t *bps,
    size_t nbps);
zv_request_task_t *zv_request_task_create(zv_request_t zvr);
void zv_request_task_free(zv_request_task_t *task);

/*
 * platform dependent functions exported to platform independent code
 */
void zvol_os_free(zvol_state_t *zv);
int zvol_os_rename_minor(zvol_state_t *zv, const char *newname);
int zvol_os_create_minor(const char *name);
int zvol_os_update_volsize(zvol_state_t *zv, uint64_t volsize);
boolean_t zvol_os_is_zvol(const char *path);
void zvol_os_remove_minor(zvol_state_t *zv);
void zvol_os_set_disk_ro(zvol_state_t *zv, int flags);
void zvol_os_set_capacity(zvol_state_t *zv, uint64_t capacity);

#endif