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 /* 23 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <sys/spa_impl.h> 30 #include <sys/zap.h> 31 #include <sys/dsl_synctask.h> 32 33 /* 34 * Routines to manage the on-disk history log. 35 * 36 * The history log is stored as a dmu object containing 37 * <packed record length, record nvlist> tuples. 38 * 39 * Where "record nvlist" is a nvlist containing uint64_ts and strings, and 40 * "packed record length" is the packed length of the "record nvlist" stored 41 * as a little endian uint64_t. 42 * 43 * The log is implemented as a ring buffer, though the original creation 44 * of the pool ('zpool create') is never overwritten. 45 * 46 * The history log is tracked as object 'spa_t::spa_history'. The bonus buffer 47 * of 'spa_history' stores the offsets for logging/retrieving history as 48 * 'spa_history_phys_t'. 'sh_pool_create_len' is the ending offset in bytes of 49 * where the 'zpool create' record is stored. This allows us to never 50 * overwrite the original creation of the pool. 'sh_phys_max_off' is the 51 * physical ending offset in bytes of the log. This tells you the length of 52 * the buffer. 'sh_eof' is the logical EOF (in bytes). Whenever a record 53 * is added, 'sh_eof' is incremented by the the size of the record. 54 * 'sh_eof' is never decremented. 'sh_bof' is the logical BOF (in bytes). 55 * This is where the consumer should start reading from after reading in 56 * the 'zpool create' portion of the log. 57 * 58 * 'sh_records_lost' keeps track of how many records have been overwritten 59 * and permanently lost. 60 */ 61 62 typedef enum history_log_type { 63 LOG_CMD_CREATE, 64 LOG_CMD_NO_CREATE 65 } history_log_type_t; 66 67 typedef struct history_arg { 68 const char *ha_history_str; 69 history_log_type_t ha_log_type; 70 } history_arg_t; 71 72 /* convert a logical offset to physical */ 73 static uint64_t 74 spa_history_log_to_phys(uint64_t log_off, spa_history_phys_t *shpp) 75 { 76 uint64_t phys_len; 77 78 phys_len = shpp->sh_phys_max_off - shpp->sh_pool_create_len; 79 return ((log_off - shpp->sh_pool_create_len) % phys_len 80 + shpp->sh_pool_create_len); 81 } 82 83 void 84 spa_history_create_obj(spa_t *spa, dmu_tx_t *tx) 85 { 86 dmu_buf_t *dbp; 87 spa_history_phys_t *shpp; 88 objset_t *mos = spa->spa_meta_objset; 89 90 ASSERT(spa->spa_history == 0); 91 spa->spa_history = dmu_object_alloc(mos, DMU_OT_SPA_HISTORY, 92 SPA_MAXBLOCKSIZE, DMU_OT_SPA_HISTORY_OFFSETS, 93 sizeof (spa_history_phys_t), tx); 94 95 VERIFY(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT, 96 DMU_POOL_HISTORY, sizeof (uint64_t), 1, 97 &spa->spa_history, tx) == 0); 98 99 VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp)); 100 ASSERT(dbp->db_size >= sizeof (spa_history_phys_t)); 101 102 shpp = dbp->db_data; 103 dmu_buf_will_dirty(dbp, tx); 104 105 /* 106 * Figure out maximum size of history log. We set it at 107 * 1% of pool size, with a max of 32MB and min of 128KB. 108 */ 109 shpp->sh_phys_max_off = spa_get_dspace(spa) / 100; 110 shpp->sh_phys_max_off = MIN(shpp->sh_phys_max_off, 32<<20); 111 shpp->sh_phys_max_off = MAX(shpp->sh_phys_max_off, 128<<10); 112 113 dmu_buf_rele(dbp, FTAG); 114 } 115 116 /* 117 * Change 'sh_bof' to the beginning of the next record. 118 */ 119 static int 120 spa_history_advance_bof(spa_t *spa, spa_history_phys_t *shpp) 121 { 122 objset_t *mos = spa->spa_meta_objset; 123 uint64_t firstread, reclen, phys_bof; 124 char buf[sizeof (reclen)]; 125 int err; 126 127 phys_bof = spa_history_log_to_phys(shpp->sh_bof, shpp); 128 firstread = MIN(sizeof (reclen), shpp->sh_phys_max_off - phys_bof); 129 130 if ((err = dmu_read(mos, spa->spa_history, phys_bof, firstread, 131 buf)) != 0) 132 return (err); 133 if (firstread != sizeof (reclen)) { 134 if ((err = dmu_read(mos, spa->spa_history, 135 shpp->sh_pool_create_len, sizeof (reclen) - firstread, 136 buf + firstread)) != 0) 137 return (err); 138 } 139 140 reclen = LE_64(*((uint64_t *)buf)); 141 shpp->sh_bof += reclen + sizeof (reclen); 142 shpp->sh_records_lost++; 143 return (0); 144 } 145 146 static int 147 spa_history_write(spa_t *spa, void *buf, uint64_t len, spa_history_phys_t *shpp, 148 dmu_tx_t *tx) 149 { 150 uint64_t firstwrite, phys_eof; 151 objset_t *mos = spa->spa_meta_objset; 152 int err; 153 154 ASSERT(MUTEX_HELD(&spa->spa_history_lock)); 155 156 /* see if we need to reset logical BOF */ 157 while (shpp->sh_phys_max_off - shpp->sh_pool_create_len - 158 (shpp->sh_eof - shpp->sh_bof) <= len) { 159 if ((err = spa_history_advance_bof(spa, shpp)) != 0) 160 return (err); 161 } 162 163 phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp); 164 firstwrite = MIN(len, shpp->sh_phys_max_off - phys_eof); 165 shpp->sh_eof += len; 166 dmu_write(mos, spa->spa_history, phys_eof, firstwrite, buf, tx); 167 168 len -= firstwrite; 169 if (len > 0) { 170 /* write out the rest at the beginning of physical file */ 171 dmu_write(mos, spa->spa_history, shpp->sh_pool_create_len, 172 len, (char *)buf + firstwrite, tx); 173 } 174 175 return (0); 176 } 177 178 /* 179 * Write out a history event. 180 */ 181 void 182 spa_history_log_sync(void *arg1, void *arg2, dmu_tx_t *tx) 183 { 184 spa_t *spa = arg1; 185 history_arg_t *hap = arg2; 186 const char *history_str = hap->ha_history_str; 187 objset_t *mos = spa->spa_meta_objset; 188 dmu_buf_t *dbp; 189 spa_history_phys_t *shpp; 190 size_t reclen; 191 uint64_t le_len; 192 nvlist_t *nvrecord; 193 char *record_packed = NULL; 194 int ret; 195 196 if (history_str == NULL) 197 return; 198 199 /* 200 * If we have an older pool that doesn't have a command 201 * history object, create it now. 202 */ 203 mutex_enter(&spa->spa_history_lock); 204 if (!spa->spa_history) 205 spa_history_create_obj(spa, tx); 206 mutex_exit(&spa->spa_history_lock); 207 208 /* 209 * Get the offset of where we need to write via the bonus buffer. 210 * Update the offset when the write completes. 211 */ 212 VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp)); 213 shpp = dbp->db_data; 214 215 dmu_buf_will_dirty(dbp, tx); 216 217 #ifdef ZFS_DEBUG 218 { 219 dmu_object_info_t doi; 220 dmu_object_info_from_db(dbp, &doi); 221 ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS); 222 } 223 #endif 224 225 /* construct a nvlist of the current time and cmd string */ 226 VERIFY(nvlist_alloc(&nvrecord, NV_UNIQUE_NAME, KM_SLEEP) == 0); 227 VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_TIME, 228 gethrestime_sec()) == 0); 229 VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_CMD, history_str) == 0); 230 VERIFY(nvlist_pack(nvrecord, &record_packed, &reclen, 231 NV_ENCODE_XDR, KM_SLEEP) == 0); 232 233 mutex_enter(&spa->spa_history_lock); 234 if (hap->ha_log_type == LOG_CMD_CREATE) 235 VERIFY(shpp->sh_eof == shpp->sh_pool_create_len); 236 237 /* write out the packed length as little endian */ 238 le_len = LE_64((uint64_t)reclen); 239 ret = spa_history_write(spa, &le_len, sizeof (le_len), shpp, tx); 240 if (!ret) 241 ret = spa_history_write(spa, record_packed, reclen, shpp, tx); 242 243 if (!ret && hap->ha_log_type == LOG_CMD_CREATE) { 244 shpp->sh_pool_create_len += sizeof (le_len) + reclen; 245 shpp->sh_bof = shpp->sh_pool_create_len; 246 } 247 248 mutex_exit(&spa->spa_history_lock); 249 nvlist_free(nvrecord); 250 kmem_free(record_packed, reclen); 251 dmu_buf_rele(dbp, FTAG); 252 } 253 254 /* 255 * Write out a history event. 256 */ 257 int 258 spa_history_log(spa_t *spa, const char *history_str, uint64_t pool_create) 259 { 260 history_arg_t ha; 261 262 ha.ha_history_str = history_str; 263 ha.ha_log_type = pool_create ? LOG_CMD_CREATE : LOG_CMD_NO_CREATE; 264 return (dsl_sync_task_do(spa_get_dsl(spa), NULL, spa_history_log_sync, 265 spa, &ha, 0)); 266 } 267 268 /* 269 * Read out the command history. 270 */ 271 int 272 spa_history_get(spa_t *spa, uint64_t *offp, uint64_t *len, char *buf) 273 { 274 objset_t *mos = spa->spa_meta_objset; 275 dmu_buf_t *dbp; 276 uint64_t read_len, phys_read_off, phys_eof; 277 uint64_t leftover = 0; 278 spa_history_phys_t *shpp; 279 int err; 280 281 /* 282 * If the command history doesn't exist (older pool), 283 * that's ok, just return ENOENT. 284 */ 285 if (!spa->spa_history) 286 return (ENOENT); 287 288 if ((err = dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp)) != 0) 289 return (err); 290 shpp = dbp->db_data; 291 292 #ifdef ZFS_DEBUG 293 { 294 dmu_object_info_t doi; 295 dmu_object_info_from_db(dbp, &doi); 296 ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS); 297 } 298 #endif 299 300 mutex_enter(&spa->spa_history_lock); 301 phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp); 302 303 if (*offp < shpp->sh_pool_create_len) { 304 /* read in just the zpool create history */ 305 phys_read_off = *offp; 306 read_len = MIN(*len, shpp->sh_pool_create_len - 307 phys_read_off); 308 } else { 309 /* 310 * Need to reset passed in offset to BOF if the passed in 311 * offset has since been overwritten. 312 */ 313 *offp = MAX(*offp, shpp->sh_bof); 314 phys_read_off = spa_history_log_to_phys(*offp, shpp); 315 316 /* 317 * Read up to the minimum of what the user passed down or 318 * the EOF (physical or logical). If we hit physical EOF, 319 * use 'leftover' to read from the physical BOF. 320 */ 321 if (phys_read_off <= phys_eof) { 322 read_len = MIN(*len, phys_eof - phys_read_off); 323 } else { 324 read_len = MIN(*len, 325 shpp->sh_phys_max_off - phys_read_off); 326 if (phys_read_off + *len > shpp->sh_phys_max_off) { 327 leftover = MIN(*len - read_len, 328 phys_eof - shpp->sh_pool_create_len); 329 } 330 } 331 } 332 333 /* offset for consumer to use next */ 334 *offp += read_len + leftover; 335 336 /* tell the consumer how much you actually read */ 337 *len = read_len + leftover; 338 339 if (read_len == 0) { 340 mutex_exit(&spa->spa_history_lock); 341 dmu_buf_rele(dbp, FTAG); 342 return (0); 343 } 344 345 err = dmu_read(mos, spa->spa_history, phys_read_off, read_len, buf); 346 if (leftover && err == 0) { 347 err = dmu_read(mos, spa->spa_history, shpp->sh_pool_create_len, 348 leftover, buf + read_len); 349 } 350 mutex_exit(&spa->spa_history_lock); 351 352 dmu_buf_rele(dbp, FTAG); 353 return (err); 354 } 355