include/sys/dsl_synctask.h

   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 https://opensource.org/licenses/CDDL-1.0.
  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 (bounded
  45          * by spa_max_slop), the operation will fail.  Operations which are
  46          * logically creating things should use this (e.g. "zfs create", "zfs
  47          * snapshot").  User writes (via the ZPL / ZVOL) also fail at this
  48          * point.
  49          */
  50         ZFS_SPACE_CHECK_NORMAL,
  51
  52         /*
  53          * Space check allows use of half the slop space.  If there
  54          * is less than 1.6% free space, the operation will fail.  Most
  55          * operations should use this (e.g. "zfs set", "zfs rename"),
  56          * because we want them to succeed even after user writes are failing,
  57          * so that they can be used as part of the space recovery process.
  58          */
  59         ZFS_SPACE_CHECK_RESERVED,
  60
  61         /*
  62          * Space check allows use of three quarters of the slop space.
  63          * If there is less than 0.8% free space, the operation will
  64          * fail.
  65          */
  66         ZFS_SPACE_CHECK_EXTRA_RESERVED,
  67
  68         /*
  69          * In all cases "zfs destroy" is expected to result in an net
  70          * reduction of space, except one. When the pool has a
  71          * checkpoint, space freed by "zfs destroy" will not actually
  72          * free anything internally. Thus, it starts failing after
  73          * three quarters of the slop space is exceeded.
  74          */
  75         ZFS_SPACE_CHECK_DESTROY = ZFS_SPACE_CHECK_EXTRA_RESERVED,
  76
  77         /*
  78          * A channel program can run a "zfs destroy" as part of its
  79          * script and therefore has the same space_check policy when
  80          * being evaluated.
  81          */
  82         ZFS_SPACE_CHECK_ZCP_EVAL = ZFS_SPACE_CHECK_DESTROY,
  83
  84         /*
  85          * No space check is performed. This level of space check should
  86          * be used cautiously as operations that use it can even run when
  87          * 0.8% capacity is left for use. In this scenario, if there is a
  88          * checkpoint, async destroys are suspended and any kind of freeing
  89          * can potentially add space instead of freeing it.
  90          *
  91          * See also the comments above spa_slop_shift.
  92          */
  93         ZFS_SPACE_CHECK_NONE,
  94
  95         ZFS_SPACE_CHECK_DISCARD_CHECKPOINT = ZFS_SPACE_CHECK_NONE,
  96
  97 } zfs_space_check_t;
  98
  99 typedef struct dsl_sync_task {
 100         txg_node_t dst_node;
 101         struct dsl_pool *dst_pool;
 102         uint64_t dst_txg;
 103         int dst_space;
 104         zfs_space_check_t dst_space_check;
 105         dsl_checkfunc_t *dst_checkfunc;
 106         dsl_syncfunc_t *dst_syncfunc;
 107         void *dst_arg;
 108         int dst_error;
 109         boolean_t dst_nowaiter;
 110 } dsl_sync_task_t;
 111
 112 void dsl_sync_task_sync(dsl_sync_task_t *, dmu_tx_t *);
 113 int dsl_sync_task(const char *, dsl_checkfunc_t *,
 114     dsl_syncfunc_t *, void *, int, zfs_space_check_t);
 115 void dsl_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
 116     void *, dmu_tx_t *);
 117 int dsl_early_sync_task(const char *, dsl_checkfunc_t *,
 118     dsl_syncfunc_t *, void *, int, zfs_space_check_t);
 119 void dsl_early_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
 120     void *, dmu_tx_t *);
 121 int dsl_sync_task_sig(const char *, dsl_checkfunc_t *, dsl_syncfunc_t *,
 122     dsl_sigfunc_t *, void *, int, zfs_space_check_t);
 123
 124 #ifdef  __cplusplus
 125 }
 126 #endif
 127
 128 #endif /* _SYS_DSL_SYNCTASK_H */