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 * Copyright (c) 2014 Integros [integros.com] 25 */ 26 27 /* Portions Copyright 2010 Robert Milkowski */ 28 29 #ifndef _SYS_ZIL_IMPL_H 30 #define _SYS_ZIL_IMPL_H 31 32 #include <sys/zil.h> 33 #include <sys/dmu_objset.h> 34 35 #ifdef __cplusplus 36 extern "C" { 37 #endif 38 39 /* 40 * Possbile states for a given lwb structure. 41 * 42 * An lwb will start out in the "closed" state, and then transition to 43 * the "opened" state via a call to zil_lwb_write_open(). When 44 * transitioning from "closed" to "opened" the zilog's "zl_issuer_lock" 45 * must be held. 46 * 47 * After the lwb is "opened", it can transition into the "issued" state 48 * via zil_lwb_write_issue(). Again, the zilog's "zl_issuer_lock" must 49 * be held when making this transition. 50 * 51 * After the lwb's write zio completes, it transitions into the "write 52 * done" state via zil_lwb_write_done(); and then into the "flush done" 53 * state via zil_lwb_flush_vdevs_done(). When transitioning from 54 * "issued" to "write done", and then from "write done" to "flush done", 55 * the zilog's "zl_lock" must be held, *not* the "zl_issuer_lock". 56 * 57 * The zilog's "zl_issuer_lock" can become heavily contended in certain 58 * workloads, so we specifically avoid acquiring that lock when 59 * transitioning an lwb from "issued" to "done". This allows us to avoid 60 * having to acquire the "zl_issuer_lock" for each lwb ZIO completion, 61 * which would have added more lock contention on an already heavily 62 * contended lock. 63 * 64 * Additionally, correctness when reading an lwb's state is often 65 * acheived by exploiting the fact that these state transitions occur in 66 * this specific order; i.e. "closed" to "opened" to "issued" to "done". 67 * 68 * Thus, if an lwb is in the "closed" or "opened" state, holding the 69 * "zl_issuer_lock" will prevent a concurrent thread from transitioning 70 * that lwb to the "issued" state. Likewise, if an lwb is already in the 71 * "issued" state, holding the "zl_lock" will prevent a concurrent 72 * thread from transitioning that lwb to the "write done" state. 73 */ 74 typedef enum { 75 LWB_STATE_CLOSED, 76 LWB_STATE_OPENED, 77 LWB_STATE_ISSUED, 78 LWB_STATE_WRITE_DONE, 79 LWB_STATE_FLUSH_DONE, 80 LWB_NUM_STATES 81 } lwb_state_t; 82 83 /* 84 * Log write block (lwb) 85 * 86 * Prior to an lwb being issued to disk via zil_lwb_write_issue(), it 87 * will be protected by the zilog's "zl_issuer_lock". Basically, prior 88 * to it being issued, it will only be accessed by the thread that's 89 * holding the "zl_issuer_lock". After the lwb is issued, the zilog's 90 * "zl_lock" is used to protect the lwb against concurrent access. 91 */ 92 typedef struct lwb { 93 zilog_t *lwb_zilog; /* back pointer to log struct */ 94 blkptr_t lwb_blk; /* on disk address of this log blk */ 95 boolean_t lwb_slog; /* lwb_blk is on SLOG device */ 96 int lwb_nused; /* # used bytes in buffer */ 97 int lwb_sz; /* size of block and buffer */ 98 lwb_state_t lwb_state; /* the state of this lwb */ 99 char *lwb_buf; /* log write buffer */ 100 zio_t *lwb_write_zio; /* zio for the lwb buffer */ 101 zio_t *lwb_root_zio; /* root zio for lwb write and flushes */ 102 dmu_tx_t *lwb_tx; /* tx for log block allocation */ 103 uint64_t lwb_max_txg; /* highest txg in this lwb */ 104 list_node_t lwb_node; /* zilog->zl_lwb_list linkage */ 105 list_t lwb_waiters; /* list of zil_commit_waiter's */ 106 avl_tree_t lwb_vdev_tree; /* vdevs to flush after lwb write */ 107 kmutex_t lwb_vdev_lock; /* protects lwb_vdev_tree */ 108 hrtime_t lwb_issued_timestamp; /* when was the lwb issued? */ 109 } lwb_t; 110 111 /* 112 * ZIL commit waiter. 113 * 114 * This structure is allocated each time zil_commit() is called, and is 115 * used by zil_commit() to communicate with other parts of the ZIL, such 116 * that zil_commit() can know when it safe for it return. For more 117 * details, see the comment above zil_commit(). 118 * 119 * The "zcw_lock" field is used to protect the commit waiter against 120 * concurrent access. This lock is often acquired while already holding 121 * the zilog's "zl_issuer_lock" or "zl_lock"; see the functions 122 * zil_process_commit_list() and zil_lwb_flush_vdevs_done() as examples 123 * of this. Thus, one must be careful not to acquire the 124 * "zl_issuer_lock" or "zl_lock" when already holding the "zcw_lock"; 125 * e.g. see the zil_commit_waiter_timeout() function. 126 */ 127 typedef struct zil_commit_waiter { 128 kcondvar_t zcw_cv; /* signalled when "done" */ 129 kmutex_t zcw_lock; /* protects fields of this struct */ 130 list_node_t zcw_node; /* linkage in lwb_t:lwb_waiter list */ 131 lwb_t *zcw_lwb; /* back pointer to lwb when linked */ 132 boolean_t zcw_done; /* B_TRUE when "done", else B_FALSE */ 133 int zcw_zio_error; /* contains the zio io_error value */ 134 } zil_commit_waiter_t; 135 136 /* 137 * Intent log transaction lists 138 */ 139 typedef struct itxs { 140 list_t i_sync_list; /* list of synchronous itxs */ 141 avl_tree_t i_async_tree; /* tree of foids for async itxs */ 142 } itxs_t; 143 144 typedef struct itxg { 145 kmutex_t itxg_lock; /* lock for this structure */ 146 uint64_t itxg_txg; /* txg for this chain */ 147 itxs_t *itxg_itxs; /* sync and async itxs */ 148 } itxg_t; 149 150 /* for async nodes we build up an AVL tree of lists of async itxs per file */ 151 typedef struct itx_async_node { 152 uint64_t ia_foid; /* file object id */ 153 list_t ia_list; /* list of async itxs for this foid */ 154 avl_node_t ia_node; /* AVL tree linkage */ 155 } itx_async_node_t; 156 157 /* 158 * Vdev flushing: during a zil_commit(), we build up an AVL tree of the vdevs 159 * we've touched so we know which ones need a write cache flush at the end. 160 */ 161 typedef struct zil_vdev_node { 162 uint64_t zv_vdev; /* vdev to be flushed */ 163 avl_node_t zv_node; /* AVL tree linkage */ 164 } zil_vdev_node_t; 165 166 #define ZIL_PREV_BLKS 16 167 168 /* 169 * Stable storage intent log management structure. One per dataset. 170 */ 171 struct zilog { 172 kmutex_t zl_lock; /* protects most zilog_t fields */ 173 struct dsl_pool *zl_dmu_pool; /* DSL pool */ 174 spa_t *zl_spa; /* handle for read/write log */ 175 const zil_header_t *zl_header; /* log header buffer */ 176 objset_t *zl_os; /* object set we're logging */ 177 zil_get_data_t *zl_get_data; /* callback to get object content */ 178 lwb_t *zl_last_lwb_opened; /* most recent lwb opened */ 179 hrtime_t zl_last_lwb_latency; /* zio latency of last lwb done */ 180 uint64_t zl_lr_seq; /* on-disk log record sequence number */ 181 uint64_t zl_commit_lr_seq; /* last committed on-disk lr seq */ 182 uint64_t zl_destroy_txg; /* txg of last zil_destroy() */ 183 uint64_t zl_replayed_seq[TXG_SIZE]; /* last replayed rec seq */ 184 uint64_t zl_replaying_seq; /* current replay seq number */ 185 uint32_t zl_suspend; /* log suspend count */ 186 kcondvar_t zl_cv_suspend; /* log suspend completion */ 187 uint8_t zl_suspending; /* log is currently suspending */ 188 uint8_t zl_keep_first; /* keep first log block in destroy */ 189 uint8_t zl_replay; /* replaying records while set */ 190 uint8_t zl_stop_sync; /* for debugging */ 191 kmutex_t zl_issuer_lock; /* single writer, per ZIL, at a time */ 192 uint8_t zl_logbias; /* latency or throughput */ 193 uint8_t zl_sync; /* synchronous or asynchronous */ 194 int zl_parse_error; /* last zil_parse() error */ 195 uint64_t zl_parse_blk_seq; /* highest blk seq on last parse */ 196 uint64_t zl_parse_lr_seq; /* highest lr seq on last parse */ 197 uint64_t zl_parse_blk_count; /* number of blocks parsed */ 198 uint64_t zl_parse_lr_count; /* number of log records parsed */ 199 itxg_t zl_itxg[TXG_SIZE]; /* intent log txg chains */ 200 list_t zl_itx_commit_list; /* itx list to be committed */ 201 uint64_t zl_cur_used; /* current commit log size used */ 202 list_t zl_lwb_list; /* in-flight log write list */ 203 avl_tree_t zl_bp_tree; /* track bps during log parse */ 204 clock_t zl_replay_time; /* lbolt of when replay started */ 205 uint64_t zl_replay_blks; /* number of log blocks replayed */ 206 zil_header_t zl_old_header; /* debugging aid */ 207 uint_t zl_prev_blks[ZIL_PREV_BLKS]; /* size - sector rounded */ 208 uint_t zl_prev_rotor; /* rotor for zl_prev[] */ 209 txg_node_t zl_dirty_link; /* protected by dp_dirty_zilogs list */ 210 uint64_t zl_dirty_max_txg; /* highest txg used to dirty zilog */ 211 }; 212 213 typedef struct zil_bp_node { 214 dva_t zn_dva; 215 avl_node_t zn_node; 216 } zil_bp_node_t; 217 218 /* 219 * Maximum amount of write data that can be put into single log block. 220 */ 221 #define ZIL_MAX_LOG_DATA (SPA_OLD_MAXBLOCKSIZE - sizeof (zil_chain_t) - \ 222 sizeof (lr_write_t)) 223 224 /* 225 * Maximum amount of log space we agree to waste to reduce number of 226 * WR_NEED_COPY chunks to reduce zl_get_data() overhead (~12%). 227 */ 228 #define ZIL_MAX_WASTE_SPACE (ZIL_MAX_LOG_DATA / 8) 229 230 /* 231 * Maximum amount of write data for WR_COPIED. Fall back to WR_NEED_COPY 232 * as more space efficient if we can't fit at least two log records into 233 * maximum sized log block. 234 */ 235 #define ZIL_MAX_COPIED_DATA ((SPA_OLD_MAXBLOCKSIZE - \ 236 sizeof (zil_chain_t)) / 2 - sizeof (lr_write_t)) 237 238 #ifdef __cplusplus 239 } 240 #endif 241 242 #endif /* _SYS_ZIL_IMPL_H */ 243