Line data Source code
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 8080476 : static inline uint xlog_get_client_id(__be32 i)
27 : {
28 8080476 : 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 : /*
237 : * Per-cpu CIL tracking items
238 : */
239 : struct xlog_cil_pcp {
240 : int32_t space_used;
241 : uint32_t space_reserved;
242 : struct list_head busy_extents;
243 : struct list_head log_items;
244 : };
245 :
246 : /*
247 : * Committed Item List structure
248 : *
249 : * This structure is used to track log items that have been committed but not
250 : * yet written into the log. It is used only when the delayed logging mount
251 : * option is enabled.
252 : *
253 : * This structure tracks the list of committing checkpoint contexts so
254 : * we can avoid the problem of having to hold out new transactions during a
255 : * flush until we have a the commit record LSN of the checkpoint. We can
256 : * traverse the list of committing contexts in xlog_cil_push_lsn() to find a
257 : * sequence match and extract the commit LSN directly from there. If the
258 : * checkpoint is still in the process of committing, we can block waiting for
259 : * the commit LSN to be determined as well. This should make synchronous
260 : * operations almost as efficient as the old logging methods.
261 : */
262 : struct xfs_cil {
263 : struct xlog *xc_log;
264 : unsigned long xc_flags;
265 : atomic_t xc_iclog_hdrs;
266 : struct workqueue_struct *xc_push_wq;
267 :
268 : struct rw_semaphore xc_ctx_lock ____cacheline_aligned_in_smp;
269 : struct xfs_cil_ctx *xc_ctx;
270 :
271 : spinlock_t xc_push_lock ____cacheline_aligned_in_smp;
272 : xfs_csn_t xc_push_seq;
273 : bool xc_push_commit_stable;
274 : struct list_head xc_committing;
275 : wait_queue_head_t xc_commit_wait;
276 : wait_queue_head_t xc_start_wait;
277 : xfs_csn_t xc_current_sequence;
278 : wait_queue_head_t xc_push_wait; /* background push throttle */
279 :
280 : void __percpu *xc_pcp; /* percpu CIL structures */
281 : #ifdef CONFIG_HOTPLUG_CPU
282 : struct list_head xc_pcp_list;
283 : #endif
284 : } ____cacheline_aligned_in_smp;
285 :
286 : /* xc_flags bit values */
287 : #define XLOG_CIL_EMPTY 1
288 : #define XLOG_CIL_PCP_SPACE 2
289 :
290 : /*
291 : * The amount of log space we allow the CIL to aggregate is difficult to size.
292 : * Whatever we choose, we have to make sure we can get a reservation for the
293 : * log space effectively, that it is large enough to capture sufficient
294 : * relogging to reduce log buffer IO significantly, but it is not too large for
295 : * the log or induces too much latency when writing out through the iclogs. We
296 : * track both space consumed and the number of vectors in the checkpoint
297 : * context, so we need to decide which to use for limiting.
298 : *
299 : * Every log buffer we write out during a push needs a header reserved, which
300 : * is at least one sector and more for v2 logs. Hence we need a reservation of
301 : * at least 512 bytes per 32k of log space just for the LR headers. That means
302 : * 16KB of reservation per megabyte of delayed logging space we will consume,
303 : * plus various headers. The number of headers will vary based on the num of
304 : * io vectors, so limiting on a specific number of vectors is going to result
305 : * in transactions of varying size. IOWs, it is more consistent to track and
306 : * limit space consumed in the log rather than by the number of objects being
307 : * logged in order to prevent checkpoint ticket overruns.
308 : *
309 : * Further, use of static reservations through the log grant mechanism is
310 : * problematic. It introduces a lot of complexity (e.g. reserve grant vs write
311 : * grant) and a significant deadlock potential because regranting write space
312 : * can block on log pushes. Hence if we have to regrant log space during a log
313 : * push, we can deadlock.
314 : *
315 : * However, we can avoid this by use of a dynamic "reservation stealing"
316 : * technique during transaction commit whereby unused reservation space in the
317 : * transaction ticket is transferred to the CIL ctx commit ticket to cover the
318 : * space needed by the checkpoint transaction. This means that we never need to
319 : * specifically reserve space for the CIL checkpoint transaction, nor do we
320 : * need to regrant space once the checkpoint completes. This also means the
321 : * checkpoint transaction ticket is specific to the checkpoint context, rather
322 : * than the CIL itself.
323 : *
324 : * With dynamic reservations, we can effectively make up arbitrary limits for
325 : * the checkpoint size so long as they don't violate any other size rules.
326 : * Recovery imposes a rule that no transaction exceed half the log, so we are
327 : * limited by that. Furthermore, the log transaction reservation subsystem
328 : * tries to keep 25% of the log free, so we need to keep below that limit or we
329 : * risk running out of free log space to start any new transactions.
330 : *
331 : * In order to keep background CIL push efficient, we only need to ensure the
332 : * CIL is large enough to maintain sufficient in-memory relogging to avoid
333 : * repeated physical writes of frequently modified metadata. If we allow the CIL
334 : * to grow to a substantial fraction of the log, then we may be pinning hundreds
335 : * of megabytes of metadata in memory until the CIL flushes. This can cause
336 : * issues when we are running low on memory - pinned memory cannot be reclaimed,
337 : * and the CIL consumes a lot of memory. Hence we need to set an upper physical
338 : * size limit for the CIL that limits the maximum amount of memory pinned by the
339 : * CIL but does not limit performance by reducing relogging efficiency
340 : * significantly.
341 : *
342 : * As such, the CIL push threshold ends up being the smaller of two thresholds:
343 : * - a threshold large enough that it allows CIL to be pushed and progress to be
344 : * made without excessive blocking of incoming transaction commits. This is
345 : * defined to be 12.5% of the log space - half the 25% push threshold of the
346 : * AIL.
347 : * - small enough that it doesn't pin excessive amounts of memory but maintains
348 : * close to peak relogging efficiency. This is defined to be 16x the iclog
349 : * buffer window (32MB) as measurements have shown this to be roughly the
350 : * point of diminishing performance increases under highly concurrent
351 : * modification workloads.
352 : *
353 : * To prevent the CIL from overflowing upper commit size bounds, we introduce a
354 : * new threshold at which we block committing transactions until the background
355 : * CIL commit commences and switches to a new context. While this is not a hard
356 : * limit, it forces the process committing a transaction to the CIL to block and
357 : * yeild the CPU, giving the CIL push work a chance to be scheduled and start
358 : * work. This prevents a process running lots of transactions from overfilling
359 : * the CIL because it is not yielding the CPU. We set the blocking limit at
360 : * twice the background push space threshold so we keep in line with the AIL
361 : * push thresholds.
362 : *
363 : * Note: this is not a -hard- limit as blocking is applied after the transaction
364 : * is inserted into the CIL and the push has been triggered. It is largely a
365 : * throttling mechanism that allows the CIL push to be scheduled and run. A hard
366 : * limit will be difficult to implement without introducing global serialisation
367 : * in the CIL commit fast path, and it's not at all clear that we actually need
368 : * such hard limits given the ~7 years we've run without a hard limit before
369 : * finding the first situation where a checkpoint size overflow actually
370 : * occurred. Hence the simple throttle, and an ASSERT check to tell us that
371 : * we've overrun the max size.
372 : */
373 : #define XLOG_CIL_SPACE_LIMIT(log) \
374 : min_t(int, (log)->l_logsize >> 3, BBTOB(XLOG_TOTAL_REC_SHIFT(log)) << 4)
375 :
376 : #define XLOG_CIL_BLOCKING_SPACE_LIMIT(log) \
377 : (XLOG_CIL_SPACE_LIMIT(log) * 2)
378 :
379 : /*
380 : * ticket grant locks, queues and accounting have their own cachlines
381 : * as these are quite hot and can be operated on concurrently.
382 : */
383 : struct xlog_grant_head {
384 : spinlock_t lock ____cacheline_aligned_in_smp;
385 : struct list_head waiters;
386 : atomic64_t grant;
387 : };
388 :
389 : /*
390 : * The reservation head lsn is not made up of a cycle number and block number.
391 : * Instead, it uses a cycle number and byte number. Logs don't expect to
392 : * overflow 31 bits worth of byte offset, so using a byte number will mean
393 : * that round off problems won't occur when releasing partial reservations.
394 : */
395 : struct xlog {
396 : /* The following fields don't need locking */
397 : struct xfs_mount *l_mp; /* mount point */
398 : struct xfs_ail *l_ailp; /* AIL log is working with */
399 : struct xfs_cil *l_cilp; /* CIL log is working with */
400 : struct xfs_buftarg *l_targ; /* buftarg of log */
401 : struct workqueue_struct *l_ioend_workqueue; /* for I/O completions */
402 : struct delayed_work l_work; /* background flush work */
403 : long l_opstate; /* operational state */
404 : uint l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
405 : struct list_head *l_buf_cancel_table;
406 : int l_iclog_hsize; /* size of iclog header */
407 : int l_iclog_heads; /* # of iclog header sectors */
408 : uint l_sectBBsize; /* sector size in BBs (2^n) */
409 : int l_iclog_size; /* size of log in bytes */
410 : int l_iclog_bufs; /* number of iclog buffers */
411 : xfs_daddr_t l_logBBstart; /* start block of log */
412 : int l_logsize; /* size of log in bytes */
413 : int l_logBBsize; /* size of log in BB chunks */
414 :
415 : /* The following block of fields are changed while holding icloglock */
416 : wait_queue_head_t l_flush_wait ____cacheline_aligned_in_smp;
417 : /* waiting for iclog flush */
418 : int l_covered_state;/* state of "covering disk
419 : * log entries" */
420 : xlog_in_core_t *l_iclog; /* head log queue */
421 : spinlock_t l_icloglock; /* grab to change iclog state */
422 : int l_curr_cycle; /* Cycle number of log writes */
423 : int l_prev_cycle; /* Cycle number before last
424 : * block increment */
425 : int l_curr_block; /* current logical log block */
426 : int l_prev_block; /* previous logical log block */
427 :
428 : /*
429 : * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
430 : * read without needing to hold specific locks. To avoid operations
431 : * contending with other hot objects, place each of them on a separate
432 : * cacheline.
433 : */
434 : /* lsn of last LR on disk */
435 : atomic64_t l_last_sync_lsn ____cacheline_aligned_in_smp;
436 : /* lsn of 1st LR with unflushed * buffers */
437 : atomic64_t l_tail_lsn ____cacheline_aligned_in_smp;
438 :
439 : struct xlog_grant_head l_reserve_head;
440 : struct xlog_grant_head l_write_head;
441 :
442 : struct xfs_kobj l_kobj;
443 :
444 : /* log recovery lsn tracking (for buffer submission */
445 : xfs_lsn_t l_recovery_lsn;
446 :
447 : uint32_t l_iclog_roundoff;/* padding roundoff */
448 :
449 : /* Users of log incompat features should take a read lock. */
450 : struct rw_semaphore l_incompat_users;
451 : };
452 :
453 : /*
454 : * Bits for operational state
455 : */
456 : #define XLOG_ACTIVE_RECOVERY 0 /* in the middle of recovery */
457 : #define XLOG_RECOVERY_NEEDED 1 /* log was recovered */
458 : #define XLOG_IO_ERROR 2 /* log hit an I/O error, and being
459 : shutdown */
460 : #define XLOG_TAIL_WARN 3 /* log tail verify warning issued */
461 :
462 : static inline bool
463 : xlog_recovery_needed(struct xlog *log)
464 : {
465 44978 : return test_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
466 : }
467 :
468 : static inline bool
469 : xlog_in_recovery(struct xlog *log)
470 : {
471 1005075410 : return test_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
472 : }
473 :
474 : static inline bool
475 : xlog_is_shutdown(struct xlog *log)
476 : {
477 13693647399 : return test_bit(XLOG_IO_ERROR, &log->l_opstate);
478 : }
479 :
480 : /*
481 : * Wait until the xlog_force_shutdown() has marked the log as shut down
482 : * so xlog_is_shutdown() will always return true.
483 : */
484 : static inline void
485 1524537 : xlog_shutdown_wait(
486 : struct xlog *log)
487 : {
488 3050094 : wait_var_event(&log->l_opstate, xlog_is_shutdown(log));
489 1524537 : }
490 :
491 : /* common routines */
492 : extern int
493 : xlog_recover(
494 : struct xlog *log);
495 : extern int
496 : xlog_recover_finish(
497 : struct xlog *log);
498 : extern void
499 : xlog_recover_cancel(struct xlog *);
500 :
501 : extern __le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead,
502 : char *dp, int size);
503 :
504 : extern struct kmem_cache *xfs_log_ticket_cache;
505 : struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes,
506 : int count, bool permanent);
507 :
508 : void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
509 : void xlog_print_trans(struct xfs_trans *);
510 : int xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx,
511 : struct list_head *lv_chain, struct xlog_ticket *tic,
512 : uint32_t len);
513 : void xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket);
514 : void xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket);
515 :
516 : void xlog_state_switch_iclogs(struct xlog *log, struct xlog_in_core *iclog,
517 : int eventual_size);
518 : int xlog_state_release_iclog(struct xlog *log, struct xlog_in_core *iclog,
519 : struct xlog_ticket *ticket);
520 :
521 : /*
522 : * When we crack an atomic LSN, we sample it first so that the value will not
523 : * change while we are cracking it into the component values. This means we
524 : * will always get consistent component values to work from. This should always
525 : * be used to sample and crack LSNs that are stored and updated in atomic
526 : * variables.
527 : */
528 : static inline void
529 : xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
530 : {
531 8112045 : xfs_lsn_t val = atomic64_read(lsn);
532 :
533 3320941744 : *cycle = CYCLE_LSN(val);
534 3320941744 : *block = BLOCK_LSN(val);
535 : }
536 :
537 : /*
538 : * Calculate and assign a value to an atomic LSN variable from component pieces.
539 : */
540 : static inline void
541 : xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
542 : {
543 34672 : atomic64_set(lsn, xlog_assign_lsn(cycle, block));
544 : }
545 :
546 : /*
547 : * When we crack the grant head, we sample it first so that the value will not
548 : * change while we are cracking it into the component values. This means we
549 : * will always get consistent component values to work from.
550 : */
551 : static inline void
552 : xlog_crack_grant_head_val(int64_t val, int *cycle, int *space)
553 : {
554 7927075144 : *cycle = val >> 32;
555 7927075144 : *space = val & 0xffffffff;
556 : }
557 :
558 : static inline void
559 : xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
560 : {
561 3312829747 : xlog_crack_grant_head_val(atomic64_read(head), cycle, space);
562 : }
563 :
564 : static inline int64_t
565 : xlog_assign_grant_head_val(int cycle, int space)
566 : {
567 4614267885 : return ((int64_t)cycle << 32) | space;
568 : }
569 :
570 : static inline void
571 : xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
572 : {
573 67470 : atomic64_set(head, xlog_assign_grant_head_val(cycle, space));
574 : }
575 :
576 : /*
577 : * Committed Item List interfaces
578 : */
579 : int xlog_cil_init(struct xlog *log);
580 : void xlog_cil_init_post_recovery(struct xlog *log);
581 : void xlog_cil_destroy(struct xlog *log);
582 : bool xlog_cil_empty(struct xlog *log);
583 : void xlog_cil_commit(struct xlog *log, struct xfs_trans *tp,
584 : xfs_csn_t *commit_seq, bool regrant);
585 : void xlog_cil_set_ctx_write_state(struct xfs_cil_ctx *ctx,
586 : struct xlog_in_core *iclog);
587 :
588 :
589 : /*
590 : * CIL force routines
591 : */
592 : void xlog_cil_flush(struct xlog *log);
593 : xfs_lsn_t xlog_cil_force_seq(struct xlog *log, xfs_csn_t sequence);
594 :
595 : static inline void
596 : xlog_cil_force(struct xlog *log)
597 : {
598 2223277 : xlog_cil_force_seq(log, log->l_cilp->xc_current_sequence);
599 : }
600 :
601 : /*
602 : * Wrapper function for waiting on a wait queue serialised against wakeups
603 : * by a spinlock. This matches the semantics of all the wait queues used in the
604 : * log code.
605 : */
606 : static inline void
607 6260601 : xlog_wait(
608 : struct wait_queue_head *wq,
609 : struct spinlock *lock)
610 : __releases(lock)
611 : {
612 6260601 : DECLARE_WAITQUEUE(wait, current);
613 :
614 6260601 : add_wait_queue_exclusive(wq, &wait);
615 6260601 : __set_current_state(TASK_UNINTERRUPTIBLE);
616 6260603 : spin_unlock(lock);
617 6260582 : schedule();
618 6260061 : remove_wait_queue(wq, &wait);
619 6260117 : }
620 :
621 : int xlog_wait_on_iclog(struct xlog_in_core *iclog);
622 :
623 : /*
624 : * The LSN is valid so long as it is behind the current LSN. If it isn't, this
625 : * means that the next log record that includes this metadata could have a
626 : * smaller LSN. In turn, this means that the modification in the log would not
627 : * replay.
628 : */
629 : static inline bool
630 147492855 : xlog_valid_lsn(
631 : struct xlog *log,
632 : xfs_lsn_t lsn)
633 : {
634 147492855 : int cur_cycle;
635 147492855 : int cur_block;
636 147492855 : bool valid = true;
637 :
638 : /*
639 : * First, sample the current lsn without locking to avoid added
640 : * contention from metadata I/O. The current cycle and block are updated
641 : * (in xlog_state_switch_iclogs()) and read here in a particular order
642 : * to avoid false negatives (e.g., thinking the metadata LSN is valid
643 : * when it is not).
644 : *
645 : * The current block is always rewound before the cycle is bumped in
646 : * xlog_state_switch_iclogs() to ensure the current LSN is never seen in
647 : * a transiently forward state. Instead, we can see the LSN in a
648 : * transiently behind state if we happen to race with a cycle wrap.
649 : */
650 147492855 : cur_cycle = READ_ONCE(log->l_curr_cycle);
651 147492855 : smp_rmb();
652 147493387 : cur_block = READ_ONCE(log->l_curr_block);
653 :
654 147493387 : if ((CYCLE_LSN(lsn) > cur_cycle) ||
655 96239456 : (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) {
656 : /*
657 : * If the metadata LSN appears invalid, it's possible the check
658 : * above raced with a wrap to the next log cycle. Grab the lock
659 : * to check for sure.
660 : */
661 3 : spin_lock(&log->l_icloglock);
662 3 : cur_cycle = log->l_curr_cycle;
663 3 : cur_block = log->l_curr_block;
664 3 : spin_unlock(&log->l_icloglock);
665 :
666 3 : if ((CYCLE_LSN(lsn) > cur_cycle) ||
667 2 : (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block))
668 2 : valid = false;
669 : }
670 :
671 147493387 : return valid;
672 : }
673 :
674 : /*
675 : * Log vector and shadow buffers can be large, so we need to use kvmalloc() here
676 : * to ensure success. Unfortunately, kvmalloc() only allows GFP_KERNEL contexts
677 : * to fall back to vmalloc, so we can't actually do anything useful with gfp
678 : * flags to control the kmalloc() behaviour within kvmalloc(). Hence kmalloc()
679 : * will do direct reclaim and compaction in the slow path, both of which are
680 : * horrendously expensive. We just want kmalloc to fail fast and fall back to
681 : * vmalloc if it can't get somethign straight away from the free lists or
682 : * buddy allocator. Hence we have to open code kvmalloc outselves here.
683 : *
684 : * This assumes that the caller uses memalloc_nofs_save task context here, so
685 : * despite the use of GFP_KERNEL here, we are going to be doing GFP_NOFS
686 : * allocations. This is actually the only way to make vmalloc() do GFP_NOFS
687 : * allocations, so lets just all pretend this is a GFP_KERNEL context
688 : * operation....
689 : */
690 : static inline void *
691 1278115994 : xlog_kvmalloc(
692 : size_t buf_size)
693 : {
694 1278115994 : gfp_t flags = GFP_KERNEL;
695 1278115994 : void *p;
696 :
697 1278115994 : flags &= ~__GFP_DIRECT_RECLAIM;
698 1278115994 : flags |= __GFP_NOWARN | __GFP_NORETRY;
699 1278115994 : do {
700 1278115994 : p = kmalloc(buf_size, flags);
701 1278092826 : if (!p)
702 0 : p = vmalloc(buf_size);
703 1278092826 : } while (!p);
704 :
705 1278092826 : return p;
706 : }
707 :
708 : /*
709 : * CIL CPU dead notifier
710 : */
711 : void xlog_cil_pcp_dead(struct xlog *log, unsigned int cpu);
712 :
713 : #endif /* __XFS_LOG_PRIV_H__ */
|
