xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/mmp.h (revision bde334a8dbd66dfa70ce4d7fc9dcad6e1ae45fe4)
1 /*
2  * CDDL HEADER START
3  *
4  * This file and its contents are supplied under the terms of the
5  * Common Development and Distribution License ("CDDL"), version 1.0.
6  * You may only use this file in accordance with the terms of version
7  * 1.0 of the CDDL.
8  *
9  * A full copy of the text of the CDDL should have accompanied this
10  * source.  A copy of the CDDL is also available via the Internet at
11  * http://www.illumos.org/license/CDDL.
12  *
13  * CDDL HEADER END
14  */
15 /*
16  * Copyright (C) 2017 by Lawrence Livermore National Security, LLC.
17  */
18 
19 #ifndef _SYS_MMP_H
20 #define	_SYS_MMP_H
21 
22 #include <sys/spa.h>
23 #include <sys/zfs_context.h>
24 #include <sys/uberblock_impl.h>
25 
26 #ifdef	__cplusplus
27 extern "C" {
28 #endif
29 
30 #define	MMP_MIN_INTERVAL		100	/* ms */
31 #define	MMP_DEFAULT_INTERVAL		1000	/* ms */
32 #define	MMP_DEFAULT_IMPORT_INTERVALS	10
33 #define	MMP_DEFAULT_FAIL_INTERVALS	5
34 
35 typedef struct mmp_thread {
36 	kmutex_t	mmp_thread_lock; /* protect thread mgmt fields */
37 	kcondvar_t	mmp_thread_cv;
38 	kthread_t	*mmp_thread;
39 	uint8_t		mmp_thread_exiting;
40 	kmutex_t	mmp_io_lock;	/* protect below */
41 	hrtime_t	mmp_last_write;	/* last successful MMP write */
42 	uint64_t	mmp_delay;	/* decaying avg ns between MMP writes */
43 	uberblock_t	mmp_ub;		/* last ub written by sync */
44 	zio_t		*mmp_zio_root;	/* root of mmp write zios */
45 	uint64_t	mmp_kstat_id;	/* unique id for next MMP write kstat */
46 	int		mmp_skip_error; /* reason for last skipped write */
47 	vdev_t		*mmp_last_leaf;	/* last mmp write sent here */
48 	uint64_t	mmp_leaf_last_gen;	/* last mmp write sent here */
49 } mmp_thread_t;
50 
51 
52 extern void mmp_init(struct spa *spa);
53 extern void mmp_fini(struct spa *spa);
54 extern void mmp_thread_start(struct spa *spa);
55 extern void mmp_thread_stop(struct spa *spa);
56 extern void mmp_update_uberblock(struct spa *spa, struct uberblock *ub);
57 extern void mmp_signal_all_threads(void);
58 
59 /* Global tuning */
60 extern ulong_t zfs_multihost_interval;
61 extern uint_t zfs_multihost_fail_intervals;
62 extern uint_t zfs_multihost_import_intervals;
63 
64 #ifdef	__cplusplus
65 }
66 #endif
67 
68 #endif	/* _SYS_MMP_H */
69