xref: /freebsd/sys/contrib/openzfs/include/sys/dsl_synctask.h (revision 61145dc2b94f12f6a47344fb9aac702321880e43)
1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3  * CDDL HEADER START
4  *
5  * The contents of this file are subject to the terms of the
6  * Common Development and Distribution License (the "License").
7  * You may not use this file except in compliance with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or https://opensource.org/licenses/CDDL-1.0.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
25  */
26 
27 #ifndef	_SYS_DSL_SYNCTASK_H
28 #define	_SYS_DSL_SYNCTASK_H
29 
30 #include <sys/txg.h>
31 #include <sys/zfs_context.h>
32 
33 #ifdef	__cplusplus
34 extern "C" {
35 #endif
36 
37 struct dsl_pool;
38 
39 typedef int (dsl_checkfunc_t)(void *, dmu_tx_t *);
40 typedef void (dsl_syncfunc_t)(void *, dmu_tx_t *);
41 typedef void (dsl_sigfunc_t)(void *, dmu_tx_t *);
42 
43 typedef enum zfs_space_check {
44 	/*
45 	 * Normal space check: if there is less than 3.2% free space (bounded
46 	 * by spa_max_slop), the operation will fail.  Operations which are
47 	 * logically creating things should use this (e.g. "zfs create", "zfs
48 	 * snapshot").  User writes (via the ZPL / ZVOL) also fail at this
49 	 * point.
50 	 */
51 	ZFS_SPACE_CHECK_NORMAL,
52 
53 	/*
54 	 * Space check allows use of half the slop space.  If there
55 	 * is less than 1.6% free space, the operation will fail.  Most
56 	 * operations should use this (e.g. "zfs set", "zfs rename"),
57 	 * because we want them to succeed even after user writes are failing,
58 	 * so that they can be used as part of the space recovery process.
59 	 */
60 	ZFS_SPACE_CHECK_RESERVED,
61 
62 	/*
63 	 * Space check allows use of three quarters of the slop space.
64 	 * If there is less than 0.8% free space, the operation will
65 	 * fail.
66 	 */
67 	ZFS_SPACE_CHECK_EXTRA_RESERVED,
68 
69 	/*
70 	 * In all cases "zfs destroy" is expected to result in an net
71 	 * reduction of space, except one. When the pool has a
72 	 * checkpoint, space freed by "zfs destroy" will not actually
73 	 * free anything internally. Thus, it starts failing after
74 	 * three quarters of the slop space is exceeded.
75 	 */
76 	ZFS_SPACE_CHECK_DESTROY = ZFS_SPACE_CHECK_EXTRA_RESERVED,
77 
78 	/*
79 	 * A channel program can run a "zfs destroy" as part of its
80 	 * script and therefore has the same space_check policy when
81 	 * being evaluated.
82 	 */
83 	ZFS_SPACE_CHECK_ZCP_EVAL = ZFS_SPACE_CHECK_DESTROY,
84 
85 	/*
86 	 * No space check is performed. This level of space check should
87 	 * be used cautiously as operations that use it can even run when
88 	 * 0.8% capacity is left for use. In this scenario, if there is a
89 	 * checkpoint, async destroys are suspended and any kind of freeing
90 	 * can potentially add space instead of freeing it.
91 	 *
92 	 * See also the comments above spa_slop_shift.
93 	 */
94 	ZFS_SPACE_CHECK_NONE,
95 
96 	ZFS_SPACE_CHECK_DISCARD_CHECKPOINT = ZFS_SPACE_CHECK_NONE,
97 
98 } zfs_space_check_t;
99 
100 typedef struct dsl_sync_task {
101 	txg_node_t dst_node;
102 	struct dsl_pool *dst_pool;
103 	uint64_t dst_txg;
104 	int dst_space;
105 	zfs_space_check_t dst_space_check;
106 	dsl_checkfunc_t *dst_checkfunc;
107 	dsl_syncfunc_t *dst_syncfunc;
108 	void *dst_arg;
109 	int dst_error;
110 	boolean_t dst_nowaiter;
111 } dsl_sync_task_t;
112 
113 void dsl_sync_task_sync(dsl_sync_task_t *, dmu_tx_t *);
114 int dsl_sync_task(const char *, dsl_checkfunc_t *,
115     dsl_syncfunc_t *, void *, int, zfs_space_check_t);
116 void dsl_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
117     void *, dmu_tx_t *);
118 int dsl_early_sync_task(const char *, dsl_checkfunc_t *,
119     dsl_syncfunc_t *, void *, int, zfs_space_check_t);
120 void dsl_early_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
121     void *, dmu_tx_t *);
122 int dsl_sync_task_sig(const char *, dsl_checkfunc_t *, dsl_syncfunc_t *,
123     dsl_sigfunc_t *, void *, int, zfs_space_check_t);
124 
125 #ifdef	__cplusplus
126 }
127 #endif
128 
129 #endif /* _SYS_DSL_SYNCTASK_H */
130