xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/dsl_synctask.h (revision d0cb1fb92629bc0283c88d4719df7285c1612700)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
24  */
25 
26 #ifndef	_SYS_DSL_SYNCTASK_H
27 #define	_SYS_DSL_SYNCTASK_H
28 
29 #include <sys/txg.h>
30 #include <sys/zfs_context.h>
31 
32 #ifdef	__cplusplus
33 extern "C" {
34 #endif
35 
36 struct dsl_pool;
37 
38 typedef int (dsl_checkfunc_t)(void *, dmu_tx_t *);
39 typedef void (dsl_syncfunc_t)(void *, dmu_tx_t *);
40 typedef void (dsl_sigfunc_t)(void *, dmu_tx_t *);
41 
42 typedef enum zfs_space_check {
43 	/*
44 	 * Normal space check: if there is less than 3.2% free space,
45 	 * the operation will fail.  Operations which are logically
46 	 * creating things should use this (e.g. "zfs create", "zfs snapshot").
47 	 * User writes (via the ZPL / ZVOL) also fail at this point.
48 	 */
49 	ZFS_SPACE_CHECK_NORMAL,
50 
51 	/*
52 	 * Space check allows use of half the slop space.  If there
53 	 * is less than 1.6% free space, the operation will fail.  Most
54 	 * operations should use this (e.g. "zfs set", "zfs rename"),
55 	 * because we want them to succeed even after user writes are failing,
56 	 * so that they can be used as part of the space recovery process.
57 	 */
58 	ZFS_SPACE_CHECK_RESERVED,
59 
60 	/*
61 	 * Space check allows use of three quarters of the slop space.
62 	 * If there is less than 0.8% free space, the operation will
63 	 * fail.
64 	 */
65 	ZFS_SPACE_CHECK_EXTRA_RESERVED,
66 
67 	/*
68 	 * In all cases "zfs destroy" is expected to result in an net
69 	 * reduction of space, except one. When the pool has a
70 	 * checkpoint, space freed by "zfs destroy" will not actually
71 	 * free anything internally. Thus, it starts failing after
72 	 * three quarters of the slop space is exceeded.
73 	 */
74 	ZFS_SPACE_CHECK_DESTROY = ZFS_SPACE_CHECK_EXTRA_RESERVED,
75 
76 	/*
77 	 * A channel program can run a "zfs destroy" as part of its
78 	 * script and therefore has the same space_check policy when
79 	 * being evaluated.
80 	 */
81 	ZFS_SPACE_CHECK_ZCP_EVAL = ZFS_SPACE_CHECK_DESTROY,
82 
83 	/*
84 	 * No space check is performed. This level of space check should
85 	 * be used cautiously as operations that use it can even run when
86 	 * 0.8% capacity is left for use. In this scenario, if there is a
87 	 * checkpoint, async destroys are suspended and any kind of freeing
88 	 * can potentially add space instead of freeing it.
89 	 *
90 	 * See also the comments above spa_slop_shift.
91 	 */
92 	ZFS_SPACE_CHECK_NONE,
93 
94 	ZFS_SPACE_CHECK_DISCARD_CHECKPOINT = ZFS_SPACE_CHECK_NONE,
95 
96 } zfs_space_check_t;
97 
98 typedef struct dsl_sync_task {
99 	txg_node_t dst_node;
100 	struct dsl_pool *dst_pool;
101 	uint64_t dst_txg;
102 	int dst_space;
103 	zfs_space_check_t dst_space_check;
104 	dsl_checkfunc_t *dst_checkfunc;
105 	dsl_syncfunc_t *dst_syncfunc;
106 	void *dst_arg;
107 	int dst_error;
108 	boolean_t dst_nowaiter;
109 } dsl_sync_task_t;
110 
111 void dsl_sync_task_sync(dsl_sync_task_t *, dmu_tx_t *);
112 int dsl_sync_task(const char *, dsl_checkfunc_t *,
113     dsl_syncfunc_t *, void *, int, zfs_space_check_t);
114 void dsl_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
115     void *, int, zfs_space_check_t, dmu_tx_t *);
116 int dsl_early_sync_task(const char *, dsl_checkfunc_t *,
117     dsl_syncfunc_t *, void *, int, zfs_space_check_t);
118 void dsl_early_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
119     void *, int, zfs_space_check_t, dmu_tx_t *);
120 int dsl_sync_task_sig(const char *, dsl_checkfunc_t *, dsl_syncfunc_t *,
121     dsl_sigfunc_t *, void *, int, zfs_space_check_t);
122 
123 #ifdef	__cplusplus
124 }
125 #endif
126 
127 #endif /* _SYS_DSL_SYNCTASK_H */
128