1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc. 4 * All Rights Reserved. 5 */ 6 #ifndef __XFS_LOG_PRIV_H__ 7 #define __XFS_LOG_PRIV_H__ 8 9 struct xfs_buf; 10 struct xlog; 11 struct xlog_ticket; 12 struct xfs_mount; 13 14 /* 15 * get client id from packed copy. 16 * 17 * this hack is here because the xlog_pack code copies four bytes 18 * of xlog_op_header containing the fields oh_clientid, oh_flags 19 * and oh_res2 into the packed copy. 20 * 21 * later on this four byte chunk is treated as an int and the 22 * client id is pulled out. 23 * 24 * this has endian issues, of course. 25 */ 26 static inline uint xlog_get_client_id(__be32 i) 27 { 28 return be32_to_cpu(i) >> 24; 29 } 30 31 /* 32 * In core log state 33 */ 34 enum xlog_iclog_state { 35 XLOG_STATE_ACTIVE, /* Current IC log being written to */ 36 XLOG_STATE_WANT_SYNC, /* Want to sync this iclog; no more writes */ 37 XLOG_STATE_SYNCING, /* This IC log is syncing */ 38 XLOG_STATE_DONE_SYNC, /* Done syncing to disk */ 39 XLOG_STATE_CALLBACK, /* Callback functions now */ 40 XLOG_STATE_DIRTY, /* Dirty IC log, not ready for ACTIVE status */ 41 }; 42 43 #define XLOG_STATE_STRINGS \ 44 { XLOG_STATE_ACTIVE, "XLOG_STATE_ACTIVE" }, \ 45 { XLOG_STATE_WANT_SYNC, "XLOG_STATE_WANT_SYNC" }, \ 46 { XLOG_STATE_SYNCING, "XLOG_STATE_SYNCING" }, \ 47 { XLOG_STATE_DONE_SYNC, "XLOG_STATE_DONE_SYNC" }, \ 48 { XLOG_STATE_CALLBACK, "XLOG_STATE_CALLBACK" }, \ 49 { XLOG_STATE_DIRTY, "XLOG_STATE_DIRTY" } 50 51 /* 52 * In core log flags 53 */ 54 #define XLOG_ICL_NEED_FLUSH (1u << 0) /* iclog needs REQ_PREFLUSH */ 55 #define XLOG_ICL_NEED_FUA (1u << 1) /* iclog needs REQ_FUA */ 56 57 #define XLOG_ICL_STRINGS \ 58 { XLOG_ICL_NEED_FLUSH, "XLOG_ICL_NEED_FLUSH" }, \ 59 { XLOG_ICL_NEED_FUA, "XLOG_ICL_NEED_FUA" } 60 61 62 /* 63 * Log ticket flags 64 */ 65 #define XLOG_TIC_PERM_RESERV (1u << 0) /* permanent reservation */ 66 67 #define XLOG_TIC_FLAGS \ 68 { XLOG_TIC_PERM_RESERV, "XLOG_TIC_PERM_RESERV" } 69 70 /* 71 * Below are states for covering allocation transactions. 72 * By covering, we mean changing the h_tail_lsn in the last on-disk 73 * log write such that no allocation transactions will be re-done during 74 * recovery after a system crash. Recovery starts at the last on-disk 75 * log write. 76 * 77 * These states are used to insert dummy log entries to cover 78 * space allocation transactions which can undo non-transactional changes 79 * after a crash. Writes to a file with space 80 * already allocated do not result in any transactions. Allocations 81 * might include space beyond the EOF. So if we just push the EOF a 82 * little, the last transaction for the file could contain the wrong 83 * size. If there is no file system activity, after an allocation 84 * transaction, and the system crashes, the allocation transaction 85 * will get replayed and the file will be truncated. This could 86 * be hours/days/... after the allocation occurred. 87 * 88 * The fix for this is to do two dummy transactions when the 89 * system is idle. We need two dummy transaction because the h_tail_lsn 90 * in the log record header needs to point beyond the last possible 91 * non-dummy transaction. The first dummy changes the h_tail_lsn to 92 * the first transaction before the dummy. The second dummy causes 93 * h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn. 94 * 95 * These dummy transactions get committed when everything 96 * is idle (after there has been some activity). 97 * 98 * There are 5 states used to control this. 99 * 100 * IDLE -- no logging has been done on the file system or 101 * we are done covering previous transactions. 102 * NEED -- logging has occurred and we need a dummy transaction 103 * when the log becomes idle. 104 * DONE -- we were in the NEED state and have committed a dummy 105 * transaction. 106 * NEED2 -- we detected that a dummy transaction has gone to the 107 * on disk log with no other transactions. 108 * DONE2 -- we committed a dummy transaction when in the NEED2 state. 109 * 110 * There are two places where we switch states: 111 * 112 * 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2. 113 * We commit the dummy transaction and switch to DONE or DONE2, 114 * respectively. In all other states, we don't do anything. 115 * 116 * 2.) When we finish writing the on-disk log (xlog_state_clean_log). 117 * 118 * No matter what state we are in, if this isn't the dummy 119 * transaction going out, the next state is NEED. 120 * So, if we aren't in the DONE or DONE2 states, the next state 121 * is NEED. We can't be finishing a write of the dummy record 122 * unless it was committed and the state switched to DONE or DONE2. 123 * 124 * If we are in the DONE state and this was a write of the 125 * dummy transaction, we move to NEED2. 126 * 127 * If we are in the DONE2 state and this was a write of the 128 * dummy transaction, we move to IDLE. 129 * 130 * 131 * Writing only one dummy transaction can get appended to 132 * one file space allocation. When this happens, the log recovery 133 * code replays the space allocation and a file could be truncated. 134 * This is why we have the NEED2 and DONE2 states before going idle. 135 */ 136 137 #define XLOG_STATE_COVER_IDLE 0 138 #define XLOG_STATE_COVER_NEED 1 139 #define XLOG_STATE_COVER_DONE 2 140 #define XLOG_STATE_COVER_NEED2 3 141 #define XLOG_STATE_COVER_DONE2 4 142 143 #define XLOG_COVER_OPS 5 144 145 typedef struct xlog_ticket { 146 struct list_head t_queue; /* reserve/write queue */ 147 struct task_struct *t_task; /* task that owns this ticket */ 148 xlog_tid_t t_tid; /* transaction identifier */ 149 atomic_t t_ref; /* ticket reference count */ 150 int t_curr_res; /* current reservation */ 151 int t_unit_res; /* unit reservation */ 152 char t_ocnt; /* original unit count */ 153 char t_cnt; /* current unit count */ 154 uint8_t t_flags; /* properties of reservation */ 155 int t_iclog_hdrs; /* iclog hdrs in t_curr_res */ 156 } xlog_ticket_t; 157 158 /* 159 * - A log record header is 512 bytes. There is plenty of room to grow the 160 * xlog_rec_header_t into the reserved space. 161 * - ic_data follows, so a write to disk can start at the beginning of 162 * the iclog. 163 * - ic_forcewait is used to implement synchronous forcing of the iclog to disk. 164 * - ic_next is the pointer to the next iclog in the ring. 165 * - ic_log is a pointer back to the global log structure. 166 * - ic_size is the full size of the log buffer, minus the cycle headers. 167 * - ic_offset is the current number of bytes written to in this iclog. 168 * - ic_refcnt is bumped when someone is writing to the log. 169 * - ic_state is the state of the iclog. 170 * 171 * Because of cacheline contention on large machines, we need to separate 172 * various resources onto different cachelines. To start with, make the 173 * structure cacheline aligned. The following fields can be contended on 174 * by independent processes: 175 * 176 * - ic_callbacks 177 * - ic_refcnt 178 * - fields protected by the global l_icloglock 179 * 180 * so we need to ensure that these fields are located in separate cachelines. 181 * We'll put all the read-only and l_icloglock fields in the first cacheline, 182 * and move everything else out to subsequent cachelines. 183 */ 184 typedef struct xlog_in_core { 185 wait_queue_head_t ic_force_wait; 186 wait_queue_head_t ic_write_wait; 187 struct xlog_in_core *ic_next; 188 struct xlog_in_core *ic_prev; 189 struct xlog *ic_log; 190 u32 ic_size; 191 u32 ic_offset; 192 enum xlog_iclog_state ic_state; 193 unsigned int ic_flags; 194 void *ic_datap; /* pointer to iclog data */ 195 struct list_head ic_callbacks; 196 197 /* reference counts need their own cacheline */ 198 atomic_t ic_refcnt ____cacheline_aligned_in_smp; 199 xlog_in_core_2_t *ic_data; 200 #define ic_header ic_data->hic_header 201 #ifdef DEBUG 202 bool ic_fail_crc : 1; 203 #endif 204 struct semaphore ic_sema; 205 struct work_struct ic_end_io_work; 206 struct bio ic_bio; 207 struct bio_vec ic_bvec[]; 208 } xlog_in_core_t; 209 210 /* 211 * The CIL context is used to aggregate per-transaction details as well be 212 * passed to the iclog for checkpoint post-commit processing. After being 213 * passed to the iclog, another context needs to be allocated for tracking the 214 * next set of transactions to be aggregated into a checkpoint. 215 */ 216 struct xfs_cil; 217 218 struct xfs_cil_ctx { 219 struct xfs_cil *cil; 220 xfs_csn_t sequence; /* chkpt sequence # */ 221 xfs_lsn_t start_lsn; /* first LSN of chkpt commit */ 222 xfs_lsn_t commit_lsn; /* chkpt commit record lsn */ 223 struct xlog_in_core *commit_iclog; 224 struct xlog_ticket *ticket; /* chkpt ticket */ 225 atomic_t space_used; /* aggregate size of regions */ 226 struct list_head busy_extents; /* busy extents in chkpt */ 227 struct list_head log_items; /* log items in chkpt */ 228 struct list_head lv_chain; /* logvecs being pushed */ 229 struct list_head iclog_entry; 230 struct list_head committing; /* ctx committing list */ 231 struct work_struct discard_endio_work; 232 struct work_struct push_work; 233 atomic_t order_id; 234 235 /* 236 * CPUs that could have added items to the percpu CIL data. Access is 237 * coordinated with xc_ctx_lock. 238 */ 239 struct cpumask cil_pcpmask; 240 }; 241 242 /* 243 * Per-cpu CIL tracking items 244 */ 245 struct xlog_cil_pcp { 246 int32_t space_used; 247 uint32_t space_reserved; 248 struct list_head busy_extents; 249 struct list_head log_items; 250 }; 251 252 /* 253 * Committed Item List structure 254 * 255 * This structure is used to track log items that have been committed but not 256 * yet written into the log. It is used only when the delayed logging mount 257 * option is enabled. 258 * 259 * This structure tracks the list of committing checkpoint contexts so 260 * we can avoid the problem of having to hold out new transactions during a 261 * flush until we have a the commit record LSN of the checkpoint. We can 262 * traverse the list of committing contexts in xlog_cil_push_lsn() to find a 263 * sequence match and extract the commit LSN directly from there. If the 264 * checkpoint is still in the process of committing, we can block waiting for 265 * the commit LSN to be determined as well. This should make synchronous 266 * operations almost as efficient as the old logging methods. 267 */ 268 struct xfs_cil { 269 struct xlog *xc_log; 270 unsigned long xc_flags; 271 atomic_t xc_iclog_hdrs; 272 struct workqueue_struct *xc_push_wq; 273 274 struct rw_semaphore xc_ctx_lock ____cacheline_aligned_in_smp; 275 struct xfs_cil_ctx *xc_ctx; 276 277 spinlock_t xc_push_lock ____cacheline_aligned_in_smp; 278 xfs_csn_t xc_push_seq; 279 bool xc_push_commit_stable; 280 struct list_head xc_committing; 281 wait_queue_head_t xc_commit_wait; 282 wait_queue_head_t xc_start_wait; 283 xfs_csn_t xc_current_sequence; 284 wait_queue_head_t xc_push_wait; /* background push throttle */ 285 286 void __percpu *xc_pcp; /* percpu CIL structures */ 287 } ____cacheline_aligned_in_smp; 288 289 /* xc_flags bit values */ 290 #define XLOG_CIL_EMPTY 1 291 #define XLOG_CIL_PCP_SPACE 2 292 293 /* 294 * The amount of log space we allow the CIL to aggregate is difficult to size. 295 * Whatever we choose, we have to make sure we can get a reservation for the 296 * log space effectively, that it is large enough to capture sufficient 297 * relogging to reduce log buffer IO significantly, but it is not too large for 298 * the log or induces too much latency when writing out through the iclogs. We 299 * track both space consumed and the number of vectors in the checkpoint 300 * context, so we need to decide which to use for limiting. 301 * 302 * Every log buffer we write out during a push needs a header reserved, which 303 * is at least one sector and more for v2 logs. Hence we need a reservation of 304 * at least 512 bytes per 32k of log space just for the LR headers. That means 305 * 16KB of reservation per megabyte of delayed logging space we will consume, 306 * plus various headers. The number of headers will vary based on the num of 307 * io vectors, so limiting on a specific number of vectors is going to result 308 * in transactions of varying size. IOWs, it is more consistent to track and 309 * limit space consumed in the log rather than by the number of objects being 310 * logged in order to prevent checkpoint ticket overruns. 311 * 312 * Further, use of static reservations through the log grant mechanism is 313 * problematic. It introduces a lot of complexity (e.g. reserve grant vs write 314 * grant) and a significant deadlock potential because regranting write space 315 * can block on log pushes. Hence if we have to regrant log space during a log 316 * push, we can deadlock. 317 * 318 * However, we can avoid this by use of a dynamic "reservation stealing" 319 * technique during transaction commit whereby unused reservation space in the 320 * transaction ticket is transferred to the CIL ctx commit ticket to cover the 321 * space needed by the checkpoint transaction. This means that we never need to 322 * specifically reserve space for the CIL checkpoint transaction, nor do we 323 * need to regrant space once the checkpoint completes. This also means the 324 * checkpoint transaction ticket is specific to the checkpoint context, rather 325 * than the CIL itself. 326 * 327 * With dynamic reservations, we can effectively make up arbitrary limits for 328 * the checkpoint size so long as they don't violate any other size rules. 329 * Recovery imposes a rule that no transaction exceed half the log, so we are 330 * limited by that. Furthermore, the log transaction reservation subsystem 331 * tries to keep 25% of the log free, so we need to keep below that limit or we 332 * risk running out of free log space to start any new transactions. 333 * 334 * In order to keep background CIL push efficient, we only need to ensure the 335 * CIL is large enough to maintain sufficient in-memory relogging to avoid 336 * repeated physical writes of frequently modified metadata. If we allow the CIL 337 * to grow to a substantial fraction of the log, then we may be pinning hundreds 338 * of megabytes of metadata in memory until the CIL flushes. This can cause 339 * issues when we are running low on memory - pinned memory cannot be reclaimed, 340 * and the CIL consumes a lot of memory. Hence we need to set an upper physical 341 * size limit for the CIL that limits the maximum amount of memory pinned by the 342 * CIL but does not limit performance by reducing relogging efficiency 343 * significantly. 344 * 345 * As such, the CIL push threshold ends up being the smaller of two thresholds: 346 * - a threshold large enough that it allows CIL to be pushed and progress to be 347 * made without excessive blocking of incoming transaction commits. This is 348 * defined to be 12.5% of the log space - half the 25% push threshold of the 349 * AIL. 350 * - small enough that it doesn't pin excessive amounts of memory but maintains 351 * close to peak relogging efficiency. This is defined to be 16x the iclog 352 * buffer window (32MB) as measurements have shown this to be roughly the 353 * point of diminishing performance increases under highly concurrent 354 * modification workloads. 355 * 356 * To prevent the CIL from overflowing upper commit size bounds, we introduce a 357 * new threshold at which we block committing transactions until the background 358 * CIL commit commences and switches to a new context. While this is not a hard 359 * limit, it forces the process committing a transaction to the CIL to block and 360 * yeild the CPU, giving the CIL push work a chance to be scheduled and start 361 * work. This prevents a process running lots of transactions from overfilling 362 * the CIL because it is not yielding the CPU. We set the blocking limit at 363 * twice the background push space threshold so we keep in line with the AIL 364 * push thresholds. 365 * 366 * Note: this is not a -hard- limit as blocking is applied after the transaction 367 * is inserted into the CIL and the push has been triggered. It is largely a 368 * throttling mechanism that allows the CIL push to be scheduled and run. A hard 369 * limit will be difficult to implement without introducing global serialisation 370 * in the CIL commit fast path, and it's not at all clear that we actually need 371 * such hard limits given the ~7 years we've run without a hard limit before 372 * finding the first situation where a checkpoint size overflow actually 373 * occurred. Hence the simple throttle, and an ASSERT check to tell us that 374 * we've overrun the max size. 375 */ 376 #define XLOG_CIL_SPACE_LIMIT(log) \ 377 min_t(int, (log)->l_logsize >> 3, BBTOB(XLOG_TOTAL_REC_SHIFT(log)) << 4) 378 379 #define XLOG_CIL_BLOCKING_SPACE_LIMIT(log) \ 380 (XLOG_CIL_SPACE_LIMIT(log) * 2) 381 382 /* 383 * ticket grant locks, queues and accounting have their own cachlines 384 * as these are quite hot and can be operated on concurrently. 385 */ 386 struct xlog_grant_head { 387 spinlock_t lock ____cacheline_aligned_in_smp; 388 struct list_head waiters; 389 atomic64_t grant; 390 }; 391 392 /* 393 * The reservation head lsn is not made up of a cycle number and block number. 394 * Instead, it uses a cycle number and byte number. Logs don't expect to 395 * overflow 31 bits worth of byte offset, so using a byte number will mean 396 * that round off problems won't occur when releasing partial reservations. 397 */ 398 struct xlog { 399 /* The following fields don't need locking */ 400 struct xfs_mount *l_mp; /* mount point */ 401 struct xfs_ail *l_ailp; /* AIL log is working with */ 402 struct xfs_cil *l_cilp; /* CIL log is working with */ 403 struct xfs_buftarg *l_targ; /* buftarg of log */ 404 struct workqueue_struct *l_ioend_workqueue; /* for I/O completions */ 405 struct delayed_work l_work; /* background flush work */ 406 long l_opstate; /* operational state */ 407 uint l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */ 408 struct list_head *l_buf_cancel_table; 409 int l_iclog_hsize; /* size of iclog header */ 410 int l_iclog_heads; /* # of iclog header sectors */ 411 uint l_sectBBsize; /* sector size in BBs (2^n) */ 412 int l_iclog_size; /* size of log in bytes */ 413 int l_iclog_bufs; /* number of iclog buffers */ 414 xfs_daddr_t l_logBBstart; /* start block of log */ 415 int l_logsize; /* size of log in bytes */ 416 int l_logBBsize; /* size of log in BB chunks */ 417 418 /* The following block of fields are changed while holding icloglock */ 419 wait_queue_head_t l_flush_wait ____cacheline_aligned_in_smp; 420 /* waiting for iclog flush */ 421 int l_covered_state;/* state of "covering disk 422 * log entries" */ 423 xlog_in_core_t *l_iclog; /* head log queue */ 424 spinlock_t l_icloglock; /* grab to change iclog state */ 425 int l_curr_cycle; /* Cycle number of log writes */ 426 int l_prev_cycle; /* Cycle number before last 427 * block increment */ 428 int l_curr_block; /* current logical log block */ 429 int l_prev_block; /* previous logical log block */ 430 431 /* 432 * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and 433 * read without needing to hold specific locks. To avoid operations 434 * contending with other hot objects, place each of them on a separate 435 * cacheline. 436 */ 437 /* lsn of last LR on disk */ 438 atomic64_t l_last_sync_lsn ____cacheline_aligned_in_smp; 439 /* lsn of 1st LR with unflushed * buffers */ 440 atomic64_t l_tail_lsn ____cacheline_aligned_in_smp; 441 442 struct xlog_grant_head l_reserve_head; 443 struct xlog_grant_head l_write_head; 444 445 struct xfs_kobj l_kobj; 446 447 /* log recovery lsn tracking (for buffer submission */ 448 xfs_lsn_t l_recovery_lsn; 449 450 uint32_t l_iclog_roundoff;/* padding roundoff */ 451 452 /* Users of log incompat features should take a read lock. */ 453 struct rw_semaphore l_incompat_users; 454 }; 455 456 /* 457 * Bits for operational state 458 */ 459 #define XLOG_ACTIVE_RECOVERY 0 /* in the middle of recovery */ 460 #define XLOG_RECOVERY_NEEDED 1 /* log was recovered */ 461 #define XLOG_IO_ERROR 2 /* log hit an I/O error, and being 462 shutdown */ 463 #define XLOG_TAIL_WARN 3 /* log tail verify warning issued */ 464 465 static inline bool 466 xlog_recovery_needed(struct xlog *log) 467 { 468 return test_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate); 469 } 470 471 static inline bool 472 xlog_in_recovery(struct xlog *log) 473 { 474 return test_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate); 475 } 476 477 static inline bool 478 xlog_is_shutdown(struct xlog *log) 479 { 480 return test_bit(XLOG_IO_ERROR, &log->l_opstate); 481 } 482 483 /* 484 * Wait until the xlog_force_shutdown() has marked the log as shut down 485 * so xlog_is_shutdown() will always return true. 486 */ 487 static inline void 488 xlog_shutdown_wait( 489 struct xlog *log) 490 { 491 wait_var_event(&log->l_opstate, xlog_is_shutdown(log)); 492 } 493 494 /* common routines */ 495 extern int 496 xlog_recover( 497 struct xlog *log); 498 extern int 499 xlog_recover_finish( 500 struct xlog *log); 501 extern void 502 xlog_recover_cancel(struct xlog *); 503 504 extern __le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead, 505 char *dp, int size); 506 507 extern struct kmem_cache *xfs_log_ticket_cache; 508 struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes, 509 int count, bool permanent); 510 511 void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket); 512 void xlog_print_trans(struct xfs_trans *); 513 int xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx, 514 struct list_head *lv_chain, struct xlog_ticket *tic, 515 uint32_t len); 516 void xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket); 517 void xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket); 518 519 void xlog_state_switch_iclogs(struct xlog *log, struct xlog_in_core *iclog, 520 int eventual_size); 521 int xlog_state_release_iclog(struct xlog *log, struct xlog_in_core *iclog, 522 struct xlog_ticket *ticket); 523 524 /* 525 * When we crack an atomic LSN, we sample it first so that the value will not 526 * change while we are cracking it into the component values. This means we 527 * will always get consistent component values to work from. This should always 528 * be used to sample and crack LSNs that are stored and updated in atomic 529 * variables. 530 */ 531 static inline void 532 xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block) 533 { 534 xfs_lsn_t val = atomic64_read(lsn); 535 536 *cycle = CYCLE_LSN(val); 537 *block = BLOCK_LSN(val); 538 } 539 540 /* 541 * Calculate and assign a value to an atomic LSN variable from component pieces. 542 */ 543 static inline void 544 xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block) 545 { 546 atomic64_set(lsn, xlog_assign_lsn(cycle, block)); 547 } 548 549 /* 550 * When we crack the grant head, we sample it first so that the value will not 551 * change while we are cracking it into the component values. This means we 552 * will always get consistent component values to work from. 553 */ 554 static inline void 555 xlog_crack_grant_head_val(int64_t val, int *cycle, int *space) 556 { 557 *cycle = val >> 32; 558 *space = val & 0xffffffff; 559 } 560 561 static inline void 562 xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space) 563 { 564 xlog_crack_grant_head_val(atomic64_read(head), cycle, space); 565 } 566 567 static inline int64_t 568 xlog_assign_grant_head_val(int cycle, int space) 569 { 570 return ((int64_t)cycle << 32) | space; 571 } 572 573 static inline void 574 xlog_assign_grant_head(atomic64_t *head, int cycle, int space) 575 { 576 atomic64_set(head, xlog_assign_grant_head_val(cycle, space)); 577 } 578 579 /* 580 * Committed Item List interfaces 581 */ 582 int xlog_cil_init(struct xlog *log); 583 void xlog_cil_init_post_recovery(struct xlog *log); 584 void xlog_cil_destroy(struct xlog *log); 585 bool xlog_cil_empty(struct xlog *log); 586 void xlog_cil_commit(struct xlog *log, struct xfs_trans *tp, 587 xfs_csn_t *commit_seq, bool regrant); 588 void xlog_cil_set_ctx_write_state(struct xfs_cil_ctx *ctx, 589 struct xlog_in_core *iclog); 590 591 592 /* 593 * CIL force routines 594 */ 595 void xlog_cil_flush(struct xlog *log); 596 xfs_lsn_t xlog_cil_force_seq(struct xlog *log, xfs_csn_t sequence); 597 598 static inline void 599 xlog_cil_force(struct xlog *log) 600 { 601 xlog_cil_force_seq(log, log->l_cilp->xc_current_sequence); 602 } 603 604 /* 605 * Wrapper function for waiting on a wait queue serialised against wakeups 606 * by a spinlock. This matches the semantics of all the wait queues used in the 607 * log code. 608 */ 609 static inline void 610 xlog_wait( 611 struct wait_queue_head *wq, 612 struct spinlock *lock) 613 __releases(lock) 614 { 615 DECLARE_WAITQUEUE(wait, current); 616 617 add_wait_queue_exclusive(wq, &wait); 618 __set_current_state(TASK_UNINTERRUPTIBLE); 619 spin_unlock(lock); 620 schedule(); 621 remove_wait_queue(wq, &wait); 622 } 623 624 int xlog_wait_on_iclog(struct xlog_in_core *iclog); 625 626 /* 627 * The LSN is valid so long as it is behind the current LSN. If it isn't, this 628 * means that the next log record that includes this metadata could have a 629 * smaller LSN. In turn, this means that the modification in the log would not 630 * replay. 631 */ 632 static inline bool 633 xlog_valid_lsn( 634 struct xlog *log, 635 xfs_lsn_t lsn) 636 { 637 int cur_cycle; 638 int cur_block; 639 bool valid = true; 640 641 /* 642 * First, sample the current lsn without locking to avoid added 643 * contention from metadata I/O. The current cycle and block are updated 644 * (in xlog_state_switch_iclogs()) and read here in a particular order 645 * to avoid false negatives (e.g., thinking the metadata LSN is valid 646 * when it is not). 647 * 648 * The current block is always rewound before the cycle is bumped in 649 * xlog_state_switch_iclogs() to ensure the current LSN is never seen in 650 * a transiently forward state. Instead, we can see the LSN in a 651 * transiently behind state if we happen to race with a cycle wrap. 652 */ 653 cur_cycle = READ_ONCE(log->l_curr_cycle); 654 smp_rmb(); 655 cur_block = READ_ONCE(log->l_curr_block); 656 657 if ((CYCLE_LSN(lsn) > cur_cycle) || 658 (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) { 659 /* 660 * If the metadata LSN appears invalid, it's possible the check 661 * above raced with a wrap to the next log cycle. Grab the lock 662 * to check for sure. 663 */ 664 spin_lock(&log->l_icloglock); 665 cur_cycle = log->l_curr_cycle; 666 cur_block = log->l_curr_block; 667 spin_unlock(&log->l_icloglock); 668 669 if ((CYCLE_LSN(lsn) > cur_cycle) || 670 (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) 671 valid = false; 672 } 673 674 return valid; 675 } 676 677 /* 678 * Log vector and shadow buffers can be large, so we need to use kvmalloc() here 679 * to ensure success. Unfortunately, kvmalloc() only allows GFP_KERNEL contexts 680 * to fall back to vmalloc, so we can't actually do anything useful with gfp 681 * flags to control the kmalloc() behaviour within kvmalloc(). Hence kmalloc() 682 * will do direct reclaim and compaction in the slow path, both of which are 683 * horrendously expensive. We just want kmalloc to fail fast and fall back to 684 * vmalloc if it can't get somethign straight away from the free lists or 685 * buddy allocator. Hence we have to open code kvmalloc outselves here. 686 * 687 * This assumes that the caller uses memalloc_nofs_save task context here, so 688 * despite the use of GFP_KERNEL here, we are going to be doing GFP_NOFS 689 * allocations. This is actually the only way to make vmalloc() do GFP_NOFS 690 * allocations, so lets just all pretend this is a GFP_KERNEL context 691 * operation.... 692 */ 693 static inline void * 694 xlog_kvmalloc( 695 size_t buf_size) 696 { 697 gfp_t flags = GFP_KERNEL; 698 void *p; 699 700 flags &= ~__GFP_DIRECT_RECLAIM; 701 flags |= __GFP_NOWARN | __GFP_NORETRY; 702 do { 703 p = kmalloc(buf_size, flags); 704 if (!p) 705 p = vmalloc(buf_size); 706 } while (!p); 707 708 return p; 709 } 710 711 #endif /* __XFS_LOG_PRIV_H__ */ 712