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 #include "xfs_extent_busy.h" /* for struct xfs_busy_extents */ 10 11 struct xfs_buf; 12 struct xlog; 13 struct xlog_ticket; 14 struct xfs_mount; 15 16 /* 17 * get client id from packed copy. 18 * 19 * this hack is here because the xlog_pack code copies four bytes 20 * of xlog_op_header containing the fields oh_clientid, oh_flags 21 * and oh_res2 into the packed copy. 22 * 23 * later on this four byte chunk is treated as an int and the 24 * client id is pulled out. 25 * 26 * this has endian issues, of course. 27 */ 28 static inline uint xlog_get_client_id(__be32 i) 29 { 30 return be32_to_cpu(i) >> 24; 31 } 32 33 /* 34 * In core log state 35 */ 36 enum xlog_iclog_state { 37 XLOG_STATE_ACTIVE, /* Current IC log being written to */ 38 XLOG_STATE_WANT_SYNC, /* Want to sync this iclog; no more writes */ 39 XLOG_STATE_SYNCING, /* This IC log is syncing */ 40 XLOG_STATE_DONE_SYNC, /* Done syncing to disk */ 41 XLOG_STATE_CALLBACK, /* Callback functions now */ 42 XLOG_STATE_DIRTY, /* Dirty IC log, not ready for ACTIVE status */ 43 }; 44 45 #define XLOG_STATE_STRINGS \ 46 { XLOG_STATE_ACTIVE, "XLOG_STATE_ACTIVE" }, \ 47 { XLOG_STATE_WANT_SYNC, "XLOG_STATE_WANT_SYNC" }, \ 48 { XLOG_STATE_SYNCING, "XLOG_STATE_SYNCING" }, \ 49 { XLOG_STATE_DONE_SYNC, "XLOG_STATE_DONE_SYNC" }, \ 50 { XLOG_STATE_CALLBACK, "XLOG_STATE_CALLBACK" }, \ 51 { XLOG_STATE_DIRTY, "XLOG_STATE_DIRTY" } 52 53 /* 54 * In core log flags 55 */ 56 #define XLOG_ICL_NEED_FLUSH (1u << 0) /* iclog needs REQ_PREFLUSH */ 57 #define XLOG_ICL_NEED_FUA (1u << 1) /* iclog needs REQ_FUA */ 58 59 #define XLOG_ICL_STRINGS \ 60 { XLOG_ICL_NEED_FLUSH, "XLOG_ICL_NEED_FLUSH" }, \ 61 { XLOG_ICL_NEED_FUA, "XLOG_ICL_NEED_FUA" } 62 63 64 /* 65 * Log ticket flags 66 */ 67 #define XLOG_TIC_PERM_RESERV (1u << 0) /* permanent reservation */ 68 69 #define XLOG_TIC_FLAGS \ 70 { XLOG_TIC_PERM_RESERV, "XLOG_TIC_PERM_RESERV" } 71 72 /* 73 * Below are states for covering allocation transactions. 74 * By covering, we mean changing the h_tail_lsn in the last on-disk 75 * log write such that no allocation transactions will be re-done during 76 * recovery after a system crash. Recovery starts at the last on-disk 77 * log write. 78 * 79 * These states are used to insert dummy log entries to cover 80 * space allocation transactions which can undo non-transactional changes 81 * after a crash. Writes to a file with space 82 * already allocated do not result in any transactions. Allocations 83 * might include space beyond the EOF. So if we just push the EOF a 84 * little, the last transaction for the file could contain the wrong 85 * size. If there is no file system activity, after an allocation 86 * transaction, and the system crashes, the allocation transaction 87 * will get replayed and the file will be truncated. This could 88 * be hours/days/... after the allocation occurred. 89 * 90 * The fix for this is to do two dummy transactions when the 91 * system is idle. We need two dummy transaction because the h_tail_lsn 92 * in the log record header needs to point beyond the last possible 93 * non-dummy transaction. The first dummy changes the h_tail_lsn to 94 * the first transaction before the dummy. The second dummy causes 95 * h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn. 96 * 97 * These dummy transactions get committed when everything 98 * is idle (after there has been some activity). 99 * 100 * There are 5 states used to control this. 101 * 102 * IDLE -- no logging has been done on the file system or 103 * we are done covering previous transactions. 104 * NEED -- logging has occurred and we need a dummy transaction 105 * when the log becomes idle. 106 * DONE -- we were in the NEED state and have committed a dummy 107 * transaction. 108 * NEED2 -- we detected that a dummy transaction has gone to the 109 * on disk log with no other transactions. 110 * DONE2 -- we committed a dummy transaction when in the NEED2 state. 111 * 112 * There are two places where we switch states: 113 * 114 * 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2. 115 * We commit the dummy transaction and switch to DONE or DONE2, 116 * respectively. In all other states, we don't do anything. 117 * 118 * 2.) When we finish writing the on-disk log (xlog_state_clean_log). 119 * 120 * No matter what state we are in, if this isn't the dummy 121 * transaction going out, the next state is NEED. 122 * So, if we aren't in the DONE or DONE2 states, the next state 123 * is NEED. We can't be finishing a write of the dummy record 124 * unless it was committed and the state switched to DONE or DONE2. 125 * 126 * If we are in the DONE state and this was a write of the 127 * dummy transaction, we move to NEED2. 128 * 129 * If we are in the DONE2 state and this was a write of the 130 * dummy transaction, we move to IDLE. 131 * 132 * 133 * Writing only one dummy transaction can get appended to 134 * one file space allocation. When this happens, the log recovery 135 * code replays the space allocation and a file could be truncated. 136 * This is why we have the NEED2 and DONE2 states before going idle. 137 */ 138 139 #define XLOG_STATE_COVER_IDLE 0 140 #define XLOG_STATE_COVER_NEED 1 141 #define XLOG_STATE_COVER_DONE 2 142 #define XLOG_STATE_COVER_NEED2 3 143 #define XLOG_STATE_COVER_DONE2 4 144 145 #define XLOG_COVER_OPS 5 146 147 typedef struct xlog_ticket { 148 struct list_head t_queue; /* reserve/write queue */ 149 struct task_struct *t_task; /* task that owns this ticket */ 150 xlog_tid_t t_tid; /* transaction identifier */ 151 atomic_t t_ref; /* ticket reference count */ 152 int t_curr_res; /* current reservation */ 153 int t_unit_res; /* unit reservation */ 154 char t_ocnt; /* original unit count */ 155 char t_cnt; /* current unit count */ 156 uint8_t t_flags; /* properties of reservation */ 157 int t_iclog_hdrs; /* iclog hdrs in t_curr_res */ 158 } xlog_ticket_t; 159 160 /* 161 * - A log record header is 512 bytes. There is plenty of room to grow the 162 * xlog_rec_header_t into the reserved space. 163 * - ic_data follows, so a write to disk can start at the beginning of 164 * the iclog. 165 * - ic_forcewait is used to implement synchronous forcing of the iclog to disk. 166 * - ic_next is the pointer to the next iclog in the ring. 167 * - ic_log is a pointer back to the global log structure. 168 * - ic_size is the full size of the log buffer, minus the cycle headers. 169 * - ic_offset is the current number of bytes written to in this iclog. 170 * - ic_refcnt is bumped when someone is writing to the log. 171 * - ic_state is the state of the iclog. 172 * 173 * Because of cacheline contention on large machines, we need to separate 174 * various resources onto different cachelines. To start with, make the 175 * structure cacheline aligned. The following fields can be contended on 176 * by independent processes: 177 * 178 * - ic_callbacks 179 * - ic_refcnt 180 * - fields protected by the global l_icloglock 181 * 182 * so we need to ensure that these fields are located in separate cachelines. 183 * We'll put all the read-only and l_icloglock fields in the first cacheline, 184 * and move everything else out to subsequent cachelines. 185 */ 186 typedef struct xlog_in_core { 187 wait_queue_head_t ic_force_wait; 188 wait_queue_head_t ic_write_wait; 189 struct xlog_in_core *ic_next; 190 struct xlog_in_core *ic_prev; 191 struct xlog *ic_log; 192 u32 ic_size; 193 u32 ic_offset; 194 enum xlog_iclog_state ic_state; 195 unsigned int ic_flags; 196 void *ic_datap; /* pointer to iclog data */ 197 struct list_head ic_callbacks; 198 199 /* reference counts need their own cacheline */ 200 atomic_t ic_refcnt ____cacheline_aligned_in_smp; 201 xlog_in_core_2_t *ic_data; 202 #define ic_header ic_data->hic_header 203 #ifdef DEBUG 204 bool ic_fail_crc : 1; 205 #endif 206 struct semaphore ic_sema; 207 struct work_struct ic_end_io_work; 208 struct bio ic_bio; 209 struct bio_vec ic_bvec[]; 210 } xlog_in_core_t; 211 212 /* 213 * The CIL context is used to aggregate per-transaction details as well be 214 * passed to the iclog for checkpoint post-commit processing. After being 215 * passed to the iclog, another context needs to be allocated for tracking the 216 * next set of transactions to be aggregated into a checkpoint. 217 */ 218 struct xfs_cil; 219 220 struct xfs_cil_ctx { 221 struct xfs_cil *cil; 222 xfs_csn_t sequence; /* chkpt sequence # */ 223 xfs_lsn_t start_lsn; /* first LSN of chkpt commit */ 224 xfs_lsn_t commit_lsn; /* chkpt commit record lsn */ 225 struct xlog_in_core *commit_iclog; 226 struct xlog_ticket *ticket; /* chkpt ticket */ 227 atomic_t space_used; /* aggregate size of regions */ 228 struct xfs_busy_extents busy_extents; 229 struct list_head log_items; /* log items in chkpt */ 230 struct list_head lv_chain; /* logvecs being pushed */ 231 struct list_head iclog_entry; 232 struct list_head committing; /* ctx committing list */ 233 struct work_struct push_work; 234 atomic_t order_id; 235 236 /* 237 * CPUs that could have added items to the percpu CIL data. Access is 238 * coordinated with xc_ctx_lock. 239 */ 240 struct cpumask cil_pcpmask; 241 }; 242 243 /* 244 * Per-cpu CIL tracking items 245 */ 246 struct xlog_cil_pcp { 247 int32_t space_used; 248 uint32_t space_reserved; 249 struct list_head busy_extents; 250 struct list_head log_items; 251 }; 252 253 /* 254 * Committed Item List structure 255 * 256 * This structure is used to track log items that have been committed but not 257 * yet written into the log. It is used only when the delayed logging mount 258 * option is enabled. 259 * 260 * This structure tracks the list of committing checkpoint contexts so 261 * we can avoid the problem of having to hold out new transactions during a 262 * flush until we have a the commit record LSN of the checkpoint. We can 263 * traverse the list of committing contexts in xlog_cil_push_lsn() to find a 264 * sequence match and extract the commit LSN directly from there. If the 265 * checkpoint is still in the process of committing, we can block waiting for 266 * the commit LSN to be determined as well. This should make synchronous 267 * operations almost as efficient as the old logging methods. 268 */ 269 struct xfs_cil { 270 struct xlog *xc_log; 271 unsigned long xc_flags; 272 atomic_t xc_iclog_hdrs; 273 struct workqueue_struct *xc_push_wq; 274 275 struct rw_semaphore xc_ctx_lock ____cacheline_aligned_in_smp; 276 struct xfs_cil_ctx *xc_ctx; 277 278 spinlock_t xc_push_lock ____cacheline_aligned_in_smp; 279 xfs_csn_t xc_push_seq; 280 bool xc_push_commit_stable; 281 struct list_head xc_committing; 282 wait_queue_head_t xc_commit_wait; 283 wait_queue_head_t xc_start_wait; 284 xfs_csn_t xc_current_sequence; 285 wait_queue_head_t xc_push_wait; /* background push throttle */ 286 287 void __percpu *xc_pcp; /* percpu CIL structures */ 288 } ____cacheline_aligned_in_smp; 289 290 /* xc_flags bit values */ 291 #define XLOG_CIL_EMPTY 1 292 #define XLOG_CIL_PCP_SPACE 2 293 294 /* 295 * The amount of log space we allow the CIL to aggregate is difficult to size. 296 * Whatever we choose, we have to make sure we can get a reservation for the 297 * log space effectively, that it is large enough to capture sufficient 298 * relogging to reduce log buffer IO significantly, but it is not too large for 299 * the log or induces too much latency when writing out through the iclogs. We 300 * track both space consumed and the number of vectors in the checkpoint 301 * context, so we need to decide which to use for limiting. 302 * 303 * Every log buffer we write out during a push needs a header reserved, which 304 * is at least one sector and more for v2 logs. Hence we need a reservation of 305 * at least 512 bytes per 32k of log space just for the LR headers. That means 306 * 16KB of reservation per megabyte of delayed logging space we will consume, 307 * plus various headers. The number of headers will vary based on the num of 308 * io vectors, so limiting on a specific number of vectors is going to result 309 * in transactions of varying size. IOWs, it is more consistent to track and 310 * limit space consumed in the log rather than by the number of objects being 311 * logged in order to prevent checkpoint ticket overruns. 312 * 313 * Further, use of static reservations through the log grant mechanism is 314 * problematic. It introduces a lot of complexity (e.g. reserve grant vs write 315 * grant) and a significant deadlock potential because regranting write space 316 * can block on log pushes. Hence if we have to regrant log space during a log 317 * push, we can deadlock. 318 * 319 * However, we can avoid this by use of a dynamic "reservation stealing" 320 * technique during transaction commit whereby unused reservation space in the 321 * transaction ticket is transferred to the CIL ctx commit ticket to cover the 322 * space needed by the checkpoint transaction. This means that we never need to 323 * specifically reserve space for the CIL checkpoint transaction, nor do we 324 * need to regrant space once the checkpoint completes. This also means the 325 * checkpoint transaction ticket is specific to the checkpoint context, rather 326 * than the CIL itself. 327 * 328 * With dynamic reservations, we can effectively make up arbitrary limits for 329 * the checkpoint size so long as they don't violate any other size rules. 330 * Recovery imposes a rule that no transaction exceed half the log, so we are 331 * limited by that. Furthermore, the log transaction reservation subsystem 332 * tries to keep 25% of the log free, so we need to keep below that limit or we 333 * risk running out of free log space to start any new transactions. 334 * 335 * In order to keep background CIL push efficient, we only need to ensure the 336 * CIL is large enough to maintain sufficient in-memory relogging to avoid 337 * repeated physical writes of frequently modified metadata. If we allow the CIL 338 * to grow to a substantial fraction of the log, then we may be pinning hundreds 339 * of megabytes of metadata in memory until the CIL flushes. This can cause 340 * issues when we are running low on memory - pinned memory cannot be reclaimed, 341 * and the CIL consumes a lot of memory. Hence we need to set an upper physical 342 * size limit for the CIL that limits the maximum amount of memory pinned by the 343 * CIL but does not limit performance by reducing relogging efficiency 344 * significantly. 345 * 346 * As such, the CIL push threshold ends up being the smaller of two thresholds: 347 * - a threshold large enough that it allows CIL to be pushed and progress to be 348 * made without excessive blocking of incoming transaction commits. This is 349 * defined to be 12.5% of the log space - half the 25% push threshold of the 350 * AIL. 351 * - small enough that it doesn't pin excessive amounts of memory but maintains 352 * close to peak relogging efficiency. This is defined to be 16x the iclog 353 * buffer window (32MB) as measurements have shown this to be roughly the 354 * point of diminishing performance increases under highly concurrent 355 * modification workloads. 356 * 357 * To prevent the CIL from overflowing upper commit size bounds, we introduce a 358 * new threshold at which we block committing transactions until the background 359 * CIL commit commences and switches to a new context. While this is not a hard 360 * limit, it forces the process committing a transaction to the CIL to block and 361 * yeild the CPU, giving the CIL push work a chance to be scheduled and start 362 * work. This prevents a process running lots of transactions from overfilling 363 * the CIL because it is not yielding the CPU. We set the blocking limit at 364 * twice the background push space threshold so we keep in line with the AIL 365 * push thresholds. 366 * 367 * Note: this is not a -hard- limit as blocking is applied after the transaction 368 * is inserted into the CIL and the push has been triggered. It is largely a 369 * throttling mechanism that allows the CIL push to be scheduled and run. A hard 370 * limit will be difficult to implement without introducing global serialisation 371 * in the CIL commit fast path, and it's not at all clear that we actually need 372 * such hard limits given the ~7 years we've run without a hard limit before 373 * finding the first situation where a checkpoint size overflow actually 374 * occurred. Hence the simple throttle, and an ASSERT check to tell us that 375 * we've overrun the max size. 376 */ 377 #define XLOG_CIL_SPACE_LIMIT(log) \ 378 min_t(int, (log)->l_logsize >> 3, BBTOB(XLOG_TOTAL_REC_SHIFT(log)) << 4) 379 380 #define XLOG_CIL_BLOCKING_SPACE_LIMIT(log) \ 381 (XLOG_CIL_SPACE_LIMIT(log) * 2) 382 383 /* 384 * ticket grant locks, queues and accounting have their own cachlines 385 * as these are quite hot and can be operated on concurrently. 386 */ 387 struct xlog_grant_head { 388 spinlock_t lock ____cacheline_aligned_in_smp; 389 struct list_head waiters; 390 atomic64_t grant; 391 }; 392 393 /* 394 * The reservation head lsn is not made up of a cycle number and block number. 395 * Instead, it uses a cycle number and byte number. Logs don't expect to 396 * overflow 31 bits worth of byte offset, so using a byte number will mean 397 * that round off problems won't occur when releasing partial reservations. 398 */ 399 struct xlog { 400 /* The following fields don't need locking */ 401 struct xfs_mount *l_mp; /* mount point */ 402 struct xfs_ail *l_ailp; /* AIL log is working with */ 403 struct xfs_cil *l_cilp; /* CIL log is working with */ 404 struct xfs_buftarg *l_targ; /* buftarg of log */ 405 struct workqueue_struct *l_ioend_workqueue; /* for I/O completions */ 406 struct delayed_work l_work; /* background flush work */ 407 long l_opstate; /* operational state */ 408 uint l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */ 409 struct list_head *l_buf_cancel_table; 410 struct list_head r_dfops; /* recovered log intent items */ 411 int l_iclog_hsize; /* size of iclog header */ 412 int l_iclog_heads; /* # of iclog header sectors */ 413 uint l_sectBBsize; /* sector size in BBs (2^n) */ 414 int l_iclog_size; /* size of log in bytes */ 415 int l_iclog_bufs; /* number of iclog buffers */ 416 xfs_daddr_t l_logBBstart; /* start block of log */ 417 int l_logsize; /* size of log in bytes */ 418 int l_logBBsize; /* size of log in BB chunks */ 419 420 /* The following block of fields are changed while holding icloglock */ 421 wait_queue_head_t l_flush_wait ____cacheline_aligned_in_smp; 422 /* waiting for iclog flush */ 423 int l_covered_state;/* state of "covering disk 424 * log entries" */ 425 xlog_in_core_t *l_iclog; /* head log queue */ 426 spinlock_t l_icloglock; /* grab to change iclog state */ 427 int l_curr_cycle; /* Cycle number of log writes */ 428 int l_prev_cycle; /* Cycle number before last 429 * block increment */ 430 int l_curr_block; /* current logical log block */ 431 int l_prev_block; /* previous logical log block */ 432 433 /* 434 * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and 435 * read without needing to hold specific locks. To avoid operations 436 * contending with other hot objects, place each of them on a separate 437 * cacheline. 438 */ 439 /* lsn of last LR on disk */ 440 atomic64_t l_last_sync_lsn ____cacheline_aligned_in_smp; 441 /* lsn of 1st LR with unflushed * buffers */ 442 atomic64_t l_tail_lsn ____cacheline_aligned_in_smp; 443 444 struct xlog_grant_head l_reserve_head; 445 struct xlog_grant_head l_write_head; 446 447 struct xfs_kobj l_kobj; 448 449 /* log recovery lsn tracking (for buffer submission */ 450 xfs_lsn_t l_recovery_lsn; 451 452 uint32_t l_iclog_roundoff;/* padding roundoff */ 453 454 /* Users of log incompat features should take a read lock. */ 455 struct rw_semaphore l_incompat_users; 456 }; 457 458 /* 459 * Bits for operational state 460 */ 461 #define XLOG_ACTIVE_RECOVERY 0 /* in the middle of recovery */ 462 #define XLOG_RECOVERY_NEEDED 1 /* log was recovered */ 463 #define XLOG_IO_ERROR 2 /* log hit an I/O error, and being 464 shutdown */ 465 #define XLOG_TAIL_WARN 3 /* log tail verify warning issued */ 466 467 static inline bool 468 xlog_recovery_needed(struct xlog *log) 469 { 470 return test_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate); 471 } 472 473 static inline bool 474 xlog_in_recovery(struct xlog *log) 475 { 476 return test_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate); 477 } 478 479 static inline bool 480 xlog_is_shutdown(struct xlog *log) 481 { 482 return test_bit(XLOG_IO_ERROR, &log->l_opstate); 483 } 484 485 /* 486 * Wait until the xlog_force_shutdown() has marked the log as shut down 487 * so xlog_is_shutdown() will always return true. 488 */ 489 static inline void 490 xlog_shutdown_wait( 491 struct xlog *log) 492 { 493 wait_var_event(&log->l_opstate, xlog_is_shutdown(log)); 494 } 495 496 /* common routines */ 497 extern int 498 xlog_recover( 499 struct xlog *log); 500 extern int 501 xlog_recover_finish( 502 struct xlog *log); 503 extern void 504 xlog_recover_cancel(struct xlog *); 505 506 extern __le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead, 507 char *dp, int size); 508 509 extern struct kmem_cache *xfs_log_ticket_cache; 510 struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes, 511 int count, bool permanent); 512 513 void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket); 514 void xlog_print_trans(struct xfs_trans *); 515 int xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx, 516 struct list_head *lv_chain, struct xlog_ticket *tic, 517 uint32_t len); 518 void xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket); 519 void xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket); 520 521 void xlog_state_switch_iclogs(struct xlog *log, struct xlog_in_core *iclog, 522 int eventual_size); 523 int xlog_state_release_iclog(struct xlog *log, struct xlog_in_core *iclog, 524 struct xlog_ticket *ticket); 525 526 /* 527 * When we crack an atomic LSN, we sample it first so that the value will not 528 * change while we are cracking it into the component values. This means we 529 * will always get consistent component values to work from. This should always 530 * be used to sample and crack LSNs that are stored and updated in atomic 531 * variables. 532 */ 533 static inline void 534 xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block) 535 { 536 xfs_lsn_t val = atomic64_read(lsn); 537 538 *cycle = CYCLE_LSN(val); 539 *block = BLOCK_LSN(val); 540 } 541 542 /* 543 * Calculate and assign a value to an atomic LSN variable from component pieces. 544 */ 545 static inline void 546 xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block) 547 { 548 atomic64_set(lsn, xlog_assign_lsn(cycle, block)); 549 } 550 551 /* 552 * When we crack the grant head, we sample it first so that the value will not 553 * change while we are cracking it into the component values. This means we 554 * will always get consistent component values to work from. 555 */ 556 static inline void 557 xlog_crack_grant_head_val(int64_t val, int *cycle, int *space) 558 { 559 *cycle = val >> 32; 560 *space = val & 0xffffffff; 561 } 562 563 static inline void 564 xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space) 565 { 566 xlog_crack_grant_head_val(atomic64_read(head), cycle, space); 567 } 568 569 static inline int64_t 570 xlog_assign_grant_head_val(int cycle, int space) 571 { 572 return ((int64_t)cycle << 32) | space; 573 } 574 575 static inline void 576 xlog_assign_grant_head(atomic64_t *head, int cycle, int space) 577 { 578 atomic64_set(head, xlog_assign_grant_head_val(cycle, space)); 579 } 580 581 /* 582 * Committed Item List interfaces 583 */ 584 int xlog_cil_init(struct xlog *log); 585 void xlog_cil_init_post_recovery(struct xlog *log); 586 void xlog_cil_destroy(struct xlog *log); 587 bool xlog_cil_empty(struct xlog *log); 588 void xlog_cil_commit(struct xlog *log, struct xfs_trans *tp, 589 xfs_csn_t *commit_seq, bool regrant); 590 void xlog_cil_set_ctx_write_state(struct xfs_cil_ctx *ctx, 591 struct xlog_in_core *iclog); 592 593 594 /* 595 * CIL force routines 596 */ 597 void xlog_cil_flush(struct xlog *log); 598 xfs_lsn_t xlog_cil_force_seq(struct xlog *log, xfs_csn_t sequence); 599 600 static inline void 601 xlog_cil_force(struct xlog *log) 602 { 603 xlog_cil_force_seq(log, log->l_cilp->xc_current_sequence); 604 } 605 606 /* 607 * Wrapper function for waiting on a wait queue serialised against wakeups 608 * by a spinlock. This matches the semantics of all the wait queues used in the 609 * log code. 610 */ 611 static inline void 612 xlog_wait( 613 struct wait_queue_head *wq, 614 struct spinlock *lock) 615 __releases(lock) 616 { 617 DECLARE_WAITQUEUE(wait, current); 618 619 add_wait_queue_exclusive(wq, &wait); 620 __set_current_state(TASK_UNINTERRUPTIBLE); 621 spin_unlock(lock); 622 schedule(); 623 remove_wait_queue(wq, &wait); 624 } 625 626 int xlog_wait_on_iclog(struct xlog_in_core *iclog); 627 628 /* 629 * The LSN is valid so long as it is behind the current LSN. If it isn't, this 630 * means that the next log record that includes this metadata could have a 631 * smaller LSN. In turn, this means that the modification in the log would not 632 * replay. 633 */ 634 static inline bool 635 xlog_valid_lsn( 636 struct xlog *log, 637 xfs_lsn_t lsn) 638 { 639 int cur_cycle; 640 int cur_block; 641 bool valid = true; 642 643 /* 644 * First, sample the current lsn without locking to avoid added 645 * contention from metadata I/O. The current cycle and block are updated 646 * (in xlog_state_switch_iclogs()) and read here in a particular order 647 * to avoid false negatives (e.g., thinking the metadata LSN is valid 648 * when it is not). 649 * 650 * The current block is always rewound before the cycle is bumped in 651 * xlog_state_switch_iclogs() to ensure the current LSN is never seen in 652 * a transiently forward state. Instead, we can see the LSN in a 653 * transiently behind state if we happen to race with a cycle wrap. 654 */ 655 cur_cycle = READ_ONCE(log->l_curr_cycle); 656 smp_rmb(); 657 cur_block = READ_ONCE(log->l_curr_block); 658 659 if ((CYCLE_LSN(lsn) > cur_cycle) || 660 (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) { 661 /* 662 * If the metadata LSN appears invalid, it's possible the check 663 * above raced with a wrap to the next log cycle. Grab the lock 664 * to check for sure. 665 */ 666 spin_lock(&log->l_icloglock); 667 cur_cycle = log->l_curr_cycle; 668 cur_block = log->l_curr_block; 669 spin_unlock(&log->l_icloglock); 670 671 if ((CYCLE_LSN(lsn) > cur_cycle) || 672 (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) 673 valid = false; 674 } 675 676 return valid; 677 } 678 679 /* 680 * Log vector and shadow buffers can be large, so we need to use kvmalloc() here 681 * to ensure success. Unfortunately, kvmalloc() only allows GFP_KERNEL contexts 682 * to fall back to vmalloc, so we can't actually do anything useful with gfp 683 * flags to control the kmalloc() behaviour within kvmalloc(). Hence kmalloc() 684 * will do direct reclaim and compaction in the slow path, both of which are 685 * horrendously expensive. We just want kmalloc to fail fast and fall back to 686 * vmalloc if it can't get somethign straight away from the free lists or 687 * buddy allocator. Hence we have to open code kvmalloc outselves here. 688 * 689 * This assumes that the caller uses memalloc_nofs_save task context here, so 690 * despite the use of GFP_KERNEL here, we are going to be doing GFP_NOFS 691 * allocations. This is actually the only way to make vmalloc() do GFP_NOFS 692 * allocations, so lets just all pretend this is a GFP_KERNEL context 693 * operation.... 694 */ 695 static inline void * 696 xlog_kvmalloc( 697 size_t buf_size) 698 { 699 gfp_t flags = GFP_KERNEL; 700 void *p; 701 702 flags &= ~__GFP_DIRECT_RECLAIM; 703 flags |= __GFP_NOWARN | __GFP_NORETRY; 704 do { 705 p = kmalloc(buf_size, flags); 706 if (!p) 707 p = vmalloc(buf_size); 708 } while (!p); 709 710 return p; 711 } 712 713 #endif /* __XFS_LOG_PRIV_H__ */ 714