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, 2018 by Delphix. All rights reserved. 24 */ 25 26/* Portions Copyright 2010 Robert Milkowski */ 27 28#ifndef _SYS_ZIL_IMPL_H 29#define _SYS_ZIL_IMPL_H 30 31#include <sys/zil.h> 32#include <sys/dmu_objset.h> 33 34#ifdef __cplusplus 35extern "C" { 36#endif 37 38/* 39 * Possible states for a given lwb structure. 40 * 41 * An lwb will start out in the "new" state, and transition to the "opened" 42 * state via a call to zil_lwb_write_open() on first itx assignment. When 43 * transitioning from "new" to "opened" the zilog's "zl_issuer_lock" must be 44 * held. 45 * 46 * After the lwb is "opened", it can be assigned number of itxs and transition 47 * into the "closed" state via zil_lwb_write_close() when full or on timeout. 48 * When transitioning from "opened" to "closed" the zilog's "zl_issuer_lock" 49 * must be held. New lwb allocation also takes "zl_lock" to protect the list. 50 * 51 * After the lwb is "closed", it can transition into the "ready" state via 52 * zil_lwb_write_issue(). "zl_lock" must be held when making this transition. 53 * Since it is done by the same thread, "zl_issuer_lock" is not needed. 54 * 55 * When lwb in "ready" state receives its block pointer, it can transition to 56 * "issued". "zl_lock" must be held when making this transition. 57 * 58 * After the lwb's write zio completes, it transitions into the "write 59 * done" state via zil_lwb_write_done(); and then into the "flush done" 60 * state via zil_lwb_flush_vdevs_done(). When transitioning from 61 * "issued" to "write done", and then from "write done" to "flush done", 62 * the zilog's "zl_lock" must be held, *not* the "zl_issuer_lock". 63 * 64 * The zilog's "zl_issuer_lock" can become heavily contended in certain 65 * workloads, so we specifically avoid acquiring that lock when 66 * transitioning an lwb from "issued" to "done". This allows us to avoid 67 * having to acquire the "zl_issuer_lock" for each lwb ZIO completion, 68 * which would have added more lock contention on an already heavily 69 * contended lock. 70 * 71 * Additionally, correctness when reading an lwb's state is often 72 * achieved by exploiting the fact that these state transitions occur in 73 * this specific order; i.e. "new" to "opened" to "closed" to "ready" to 74 * "issued" to "write_done" and finally "flush_done". 75 * 76 * Thus, if an lwb is in the "new" or "opened" state, holding the 77 * "zl_issuer_lock" will prevent a concurrent thread from transitioning 78 * that lwb to the "closed" state. Likewise, if an lwb is already in the 79 * "ready" state, holding the "zl_lock" will prevent a concurrent thread 80 * from transitioning that lwb to the "issued" state. 81 */ 82typedef enum { 83 LWB_STATE_NEW, 84 LWB_STATE_OPENED, 85 LWB_STATE_CLOSED, 86 LWB_STATE_READY, 87 LWB_STATE_ISSUED, 88 LWB_STATE_WRITE_DONE, 89 LWB_STATE_FLUSH_DONE, 90 LWB_NUM_STATES 91} lwb_state_t; 92 93/* 94 * Log write block (lwb) 95 * 96 * Prior to an lwb being issued to disk via zil_lwb_write_issue(), it 97 * will be protected by the zilog's "zl_issuer_lock". Basically, prior 98 * to it being issued, it will only be accessed by the thread that's 99 * holding the "zl_issuer_lock". After the lwb is issued, the zilog's 100 * "zl_lock" is used to protect the lwb against concurrent access. 101 */ 102typedef struct lwb { 103 zilog_t *lwb_zilog; /* back pointer to log struct */ 104 blkptr_t lwb_blk; /* on disk address of this log blk */ 105 boolean_t lwb_slim; /* log block has slim format */ 106 boolean_t lwb_slog; /* lwb_blk is on SLOG device */ 107 int lwb_error; /* log block allocation error */ 108 int lwb_nmax; /* max bytes in the buffer */ 109 int lwb_nused; /* # used bytes in buffer */ 110 int lwb_nfilled; /* # filled bytes in buffer */ 111 int lwb_sz; /* size of block and buffer */ 112 lwb_state_t lwb_state; /* the state of this lwb */ 113 char *lwb_buf; /* log write buffer */ 114 zio_t *lwb_child_zio; /* parent zio for children */ 115 zio_t *lwb_write_zio; /* zio for the lwb buffer */ 116 zio_t *lwb_root_zio; /* root zio for lwb write and flushes */ 117 hrtime_t lwb_issued_timestamp; /* when was the lwb issued? */ 118 uint64_t lwb_issued_txg; /* the txg when the write is issued */ 119 uint64_t lwb_alloc_txg; /* the txg when lwb_blk is allocated */ 120 uint64_t lwb_max_txg; /* highest txg in this lwb */ 121 list_node_t lwb_node; /* zilog->zl_lwb_list linkage */ 122 list_node_t lwb_issue_node; /* linkage of lwbs ready for issue */ 123 list_t lwb_itxs; /* list of itx's */ 124 list_t lwb_waiters; /* list of zil_commit_waiter's */ 125 avl_tree_t lwb_vdev_tree; /* vdevs to flush after lwb write */ 126 kmutex_t lwb_vdev_lock; /* protects lwb_vdev_tree */ 127} lwb_t; 128 129/* 130 * ZIL commit waiter. 131 * 132 * This structure is allocated each time zil_commit() is called, and is 133 * used by zil_commit() to communicate with other parts of the ZIL, such 134 * that zil_commit() can know when it safe for it return. For more 135 * details, see the comment above zil_commit(). 136 * 137 * The "zcw_lock" field is used to protect the commit waiter against 138 * concurrent access. This lock is often acquired while already holding 139 * the zilog's "zl_issuer_lock" or "zl_lock"; see the functions 140 * zil_process_commit_list() and zil_lwb_flush_vdevs_done() as examples 141 * of this. Thus, one must be careful not to acquire the 142 * "zl_issuer_lock" or "zl_lock" when already holding the "zcw_lock"; 143 * e.g. see the zil_commit_waiter_timeout() function. 144 */ 145typedef struct zil_commit_waiter { 146 kcondvar_t zcw_cv; /* signalled when "done" */ 147 kmutex_t zcw_lock; /* protects fields of this struct */ 148 list_node_t zcw_node; /* linkage in lwb_t:lwb_waiter list */ 149 lwb_t *zcw_lwb; /* back pointer to lwb when linked */ 150 boolean_t zcw_done; /* B_TRUE when "done", else B_FALSE */ 151 int zcw_zio_error; /* contains the zio io_error value */ 152} zil_commit_waiter_t; 153 154/* 155 * Intent log transaction lists 156 */ 157typedef struct itxs { 158 list_t i_sync_list; /* list of synchronous itxs */ 159 avl_tree_t i_async_tree; /* tree of foids for async itxs */ 160} itxs_t; 161 162typedef struct itxg { 163 kmutex_t itxg_lock; /* lock for this structure */ 164 uint64_t itxg_txg; /* txg for this chain */ 165 itxs_t *itxg_itxs; /* sync and async itxs */ 166} itxg_t; 167 168/* for async nodes we build up an AVL tree of lists of async itxs per file */ 169typedef struct itx_async_node { 170 uint64_t ia_foid; /* file object id */ 171 list_t ia_list; /* list of async itxs for this foid */ 172 avl_node_t ia_node; /* AVL tree linkage */ 173} itx_async_node_t; 174 175/* 176 * Vdev flushing: during a zil_commit(), we build up an AVL tree of the vdevs 177 * we've touched so we know which ones need a write cache flush at the end. 178 */ 179typedef struct zil_vdev_node { 180 uint64_t zv_vdev; /* vdev to be flushed */ 181 avl_node_t zv_node; /* AVL tree linkage */ 182} zil_vdev_node_t; 183 184#define ZIL_BURSTS 8 185 186/* 187 * Stable storage intent log management structure. One per dataset. 188 */ 189struct zilog { 190 kmutex_t zl_lock; /* protects most zilog_t fields */ 191 struct dsl_pool *zl_dmu_pool; /* DSL pool */ 192 spa_t *zl_spa; /* handle for read/write log */ 193 const zil_header_t *zl_header; /* log header buffer */ 194 objset_t *zl_os; /* object set we're logging */ 195 zil_get_data_t *zl_get_data; /* callback to get object content */ 196 lwb_t *zl_last_lwb_opened; /* most recent lwb opened */ 197 hrtime_t zl_last_lwb_latency; /* zio latency of last lwb done */ 198 uint64_t zl_lr_seq; /* on-disk log record sequence number */ 199 uint64_t zl_commit_lr_seq; /* last committed on-disk lr seq */ 200 uint64_t zl_destroy_txg; /* txg of last zil_destroy() */ 201 uint64_t zl_replayed_seq[TXG_SIZE]; /* last replayed rec seq */ 202 uint64_t zl_replaying_seq; /* current replay seq number */ 203 uint32_t zl_suspend; /* log suspend count */ 204 kcondvar_t zl_cv_suspend; /* log suspend completion */ 205 uint8_t zl_suspending; /* log is currently suspending */ 206 uint8_t zl_keep_first; /* keep first log block in destroy */ 207 uint8_t zl_replay; /* replaying records while set */ 208 uint8_t zl_stop_sync; /* for debugging */ 209 kmutex_t zl_issuer_lock; /* single writer, per ZIL, at a time */ 210 uint8_t zl_logbias; /* latency or throughput */ 211 uint8_t zl_sync; /* synchronous or asynchronous */ 212 int zl_parse_error; /* last zil_parse() error */ 213 uint64_t zl_parse_blk_seq; /* highest blk seq on last parse */ 214 uint64_t zl_parse_lr_seq; /* highest lr seq on last parse */ 215 uint64_t zl_parse_blk_count; /* number of blocks parsed */ 216 uint64_t zl_parse_lr_count; /* number of log records parsed */ 217 itxg_t zl_itxg[TXG_SIZE]; /* intent log txg chains */ 218 list_t zl_itx_commit_list; /* itx list to be committed */ 219 uint64_t zl_cur_size; /* current burst full size */ 220 uint64_t zl_cur_left; /* current burst remaining size */ 221 uint64_t zl_cur_max; /* biggest record in current burst */ 222 list_t zl_lwb_list; /* in-flight log write list */ 223 avl_tree_t zl_bp_tree; /* track bps during log parse */ 224 clock_t zl_replay_time; /* lbolt of when replay started */ 225 uint64_t zl_replay_blks; /* number of log blocks replayed */ 226 zil_header_t zl_old_header; /* debugging aid */ 227 uint_t zl_parallel; /* workload is multi-threaded */ 228 uint_t zl_prev_rotor; /* rotor for zl_prev[] */ 229 uint_t zl_prev_opt[ZIL_BURSTS]; /* optimal block size */ 230 uint_t zl_prev_min[ZIL_BURSTS]; /* minimal first block size */ 231 txg_node_t zl_dirty_link; /* protected by dp_dirty_zilogs list */ 232 uint64_t zl_dirty_max_txg; /* highest txg used to dirty zilog */ 233 234 kmutex_t zl_lwb_io_lock; /* protect following members */ 235 uint64_t zl_lwb_inflight[TXG_SIZE]; /* io issued, but not done */ 236 kcondvar_t zl_lwb_io_cv; /* signal when the flush is done */ 237 uint64_t zl_lwb_max_issued_txg; /* max txg when lwb io issued */ 238 239 /* 240 * Max block size for this ZIL. Note that this can not be changed 241 * while the ZIL is in use because consumers (ZPL/zvol) need to take 242 * this into account when deciding between WR_COPIED and WR_NEED_COPY 243 * (see zil_max_copied_data()). 244 */ 245 uint64_t zl_max_block_size; 246 247 /* Pointer for per dataset zil sums */ 248 zil_sums_t *zl_sums; 249}; 250 251typedef struct zil_bp_node { 252 dva_t zn_dva; 253 avl_node_t zn_node; 254} zil_bp_node_t; 255 256#ifdef __cplusplus 257} 258#endif 259 260#endif /* _SYS_ZIL_IMPL_H */ 261