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1/*
2 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#ifndef __XFS_LOG_PRIV_H__
19#define __XFS_LOG_PRIV_H__
20
21struct xfs_buf;
22struct xlog;
23struct xlog_ticket;
24struct xfs_mount;
25
26/*
27 * Macros, structures, prototypes for internal log manager use.
28 */
29
30#define XLOG_MIN_ICLOGS 2
31#define XLOG_MAX_ICLOGS 8
32#define XLOG_HEADER_MAGIC_NUM 0xFEEDbabe /* Invalid cycle number */
33#define XLOG_VERSION_1 1
34#define XLOG_VERSION_2 2 /* Large IClogs, Log sunit */
35#define XLOG_VERSION_OKBITS (XLOG_VERSION_1 | XLOG_VERSION_2)
36#define XLOG_MIN_RECORD_BSIZE (16*1024) /* eventually 32k */
37#define XLOG_BIG_RECORD_BSIZE (32*1024) /* 32k buffers */
38#define XLOG_MAX_RECORD_BSIZE (256*1024)
39#define XLOG_HEADER_CYCLE_SIZE (32*1024) /* cycle data in header */
40#define XLOG_MIN_RECORD_BSHIFT 14 /* 16384 == 1 << 14 */
41#define XLOG_BIG_RECORD_BSHIFT 15 /* 32k == 1 << 15 */
42#define XLOG_MAX_RECORD_BSHIFT 18 /* 256k == 1 << 18 */
43#define XLOG_BTOLSUNIT(log, b) (((b)+(log)->l_mp->m_sb.sb_logsunit-1) / \
44 (log)->l_mp->m_sb.sb_logsunit)
45#define XLOG_LSUNITTOB(log, su) ((su) * (log)->l_mp->m_sb.sb_logsunit)
46
47#define XLOG_HEADER_SIZE 512
48
49#define XLOG_REC_SHIFT(log) \
50 BTOBB(1 << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
51 XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
52#define XLOG_TOTAL_REC_SHIFT(log) \
53 BTOBB(XLOG_MAX_ICLOGS << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
54 XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
55
56static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
57{
58 return ((xfs_lsn_t)cycle << 32) | block;
59}
60
61static inline uint xlog_get_cycle(char *ptr)
62{
63 if (be32_to_cpu(*(__be32 *)ptr) == XLOG_HEADER_MAGIC_NUM)
64 return be32_to_cpu(*((__be32 *)ptr + 1));
65 else
66 return be32_to_cpu(*(__be32 *)ptr);
67}
68
69#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
70
71#ifdef __KERNEL__
72
73/*
74 * get client id from packed copy.
75 *
76 * this hack is here because the xlog_pack code copies four bytes
77 * of xlog_op_header containing the fields oh_clientid, oh_flags
78 * and oh_res2 into the packed copy.
79 *
80 * later on this four byte chunk is treated as an int and the
81 * client id is pulled out.
82 *
83 * this has endian issues, of course.
84 */
85static inline uint xlog_get_client_id(__be32 i)
86{
87 return be32_to_cpu(i) >> 24;
88}
89
90/*
91 * In core log state
92 */
93#define XLOG_STATE_ACTIVE 0x0001 /* Current IC log being written to */
94#define XLOG_STATE_WANT_SYNC 0x0002 /* Want to sync this iclog; no more writes */
95#define XLOG_STATE_SYNCING 0x0004 /* This IC log is syncing */
96#define XLOG_STATE_DONE_SYNC 0x0008 /* Done syncing to disk */
97#define XLOG_STATE_DO_CALLBACK \
98 0x0010 /* Process callback functions */
99#define XLOG_STATE_CALLBACK 0x0020 /* Callback functions now */
100#define XLOG_STATE_DIRTY 0x0040 /* Dirty IC log, not ready for ACTIVE status*/
101#define XLOG_STATE_IOERROR 0x0080 /* IO error happened in sync'ing log */
102#define XLOG_STATE_ALL 0x7FFF /* All possible valid flags */
103#define XLOG_STATE_NOTUSED 0x8000 /* This IC log not being used */
104#endif /* __KERNEL__ */
105
106/*
107 * Flags to log operation header
108 *
109 * The first write of a new transaction will be preceded with a start
110 * record, XLOG_START_TRANS. Once a transaction is committed, a commit
111 * record is written, XLOG_COMMIT_TRANS. If a single region can not fit into
112 * the remainder of the current active in-core log, it is split up into
113 * multiple regions. Each partial region will be marked with a
114 * XLOG_CONTINUE_TRANS until the last one, which gets marked with XLOG_END_TRANS.
115 *
116 */
117#define XLOG_START_TRANS 0x01 /* Start a new transaction */
118#define XLOG_COMMIT_TRANS 0x02 /* Commit this transaction */
119#define XLOG_CONTINUE_TRANS 0x04 /* Cont this trans into new region */
120#define XLOG_WAS_CONT_TRANS 0x08 /* Cont this trans into new region */
121#define XLOG_END_TRANS 0x10 /* End a continued transaction */
122#define XLOG_UNMOUNT_TRANS 0x20 /* Unmount a filesystem transaction */
123
124#ifdef __KERNEL__
125/*
126 * Flags to log ticket
127 */
128#define XLOG_TIC_INITED 0x1 /* has been initialized */
129#define XLOG_TIC_PERM_RESERV 0x2 /* permanent reservation */
130
131#define XLOG_TIC_FLAGS \
132 { XLOG_TIC_INITED, "XLOG_TIC_INITED" }, \
133 { XLOG_TIC_PERM_RESERV, "XLOG_TIC_PERM_RESERV" }
134
135#endif /* __KERNEL__ */
136
137#define XLOG_UNMOUNT_TYPE 0x556e /* Un for Unmount */
138
139/*
140 * Flags for log structure
141 */
142#define XLOG_CHKSUM_MISMATCH 0x1 /* used only during recovery */
143#define XLOG_ACTIVE_RECOVERY 0x2 /* in the middle of recovery */
144#define XLOG_RECOVERY_NEEDED 0x4 /* log was recovered */
145#define XLOG_IO_ERROR 0x8 /* log hit an I/O error, and being
146 shutdown */
147#define XLOG_TAIL_WARN 0x10 /* log tail verify warning issued */
148
149typedef __uint32_t xlog_tid_t;
150
151#ifdef __KERNEL__
152/*
153 * Below are states for covering allocation transactions.
154 * By covering, we mean changing the h_tail_lsn in the last on-disk
155 * log write such that no allocation transactions will be re-done during
156 * recovery after a system crash. Recovery starts at the last on-disk
157 * log write.
158 *
159 * These states are used to insert dummy log entries to cover
160 * space allocation transactions which can undo non-transactional changes
161 * after a crash. Writes to a file with space
162 * already allocated do not result in any transactions. Allocations
163 * might include space beyond the EOF. So if we just push the EOF a
164 * little, the last transaction for the file could contain the wrong
165 * size. If there is no file system activity, after an allocation
166 * transaction, and the system crashes, the allocation transaction
167 * will get replayed and the file will be truncated. This could
168 * be hours/days/... after the allocation occurred.
169 *
170 * The fix for this is to do two dummy transactions when the
171 * system is idle. We need two dummy transaction because the h_tail_lsn
172 * in the log record header needs to point beyond the last possible
173 * non-dummy transaction. The first dummy changes the h_tail_lsn to
174 * the first transaction before the dummy. The second dummy causes
175 * h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn.
176 *
177 * These dummy transactions get committed when everything
178 * is idle (after there has been some activity).
179 *
180 * There are 5 states used to control this.
181 *
182 * IDLE -- no logging has been done on the file system or
183 * we are done covering previous transactions.
184 * NEED -- logging has occurred and we need a dummy transaction
185 * when the log becomes idle.
186 * DONE -- we were in the NEED state and have committed a dummy
187 * transaction.
188 * NEED2 -- we detected that a dummy transaction has gone to the
189 * on disk log with no other transactions.
190 * DONE2 -- we committed a dummy transaction when in the NEED2 state.
191 *
192 * There are two places where we switch states:
193 *
194 * 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2.
195 * We commit the dummy transaction and switch to DONE or DONE2,
196 * respectively. In all other states, we don't do anything.
197 *
198 * 2.) When we finish writing the on-disk log (xlog_state_clean_log).
199 *
200 * No matter what state we are in, if this isn't the dummy
201 * transaction going out, the next state is NEED.
202 * So, if we aren't in the DONE or DONE2 states, the next state
203 * is NEED. We can't be finishing a write of the dummy record
204 * unless it was committed and the state switched to DONE or DONE2.
205 *
206 * If we are in the DONE state and this was a write of the
207 * dummy transaction, we move to NEED2.
208 *
209 * If we are in the DONE2 state and this was a write of the
210 * dummy transaction, we move to IDLE.
211 *
212 *
213 * Writing only one dummy transaction can get appended to
214 * one file space allocation. When this happens, the log recovery
215 * code replays the space allocation and a file could be truncated.
216 * This is why we have the NEED2 and DONE2 states before going idle.
217 */
218
219#define XLOG_STATE_COVER_IDLE 0
220#define XLOG_STATE_COVER_NEED 1
221#define XLOG_STATE_COVER_DONE 2
222#define XLOG_STATE_COVER_NEED2 3
223#define XLOG_STATE_COVER_DONE2 4
224
225#define XLOG_COVER_OPS 5
226
227
228/* Ticket reservation region accounting */
229#define XLOG_TIC_LEN_MAX 15
230
231/*
232 * Reservation region
233 * As would be stored in xfs_log_iovec but without the i_addr which
234 * we don't care about.
235 */
236typedef struct xlog_res {
237 uint r_len; /* region length :4 */
238 uint r_type; /* region's transaction type :4 */
239} xlog_res_t;
240
241typedef struct xlog_ticket {
242 struct list_head t_queue; /* reserve/write queue */
243 struct task_struct *t_task; /* task that owns this ticket */
244 xlog_tid_t t_tid; /* transaction identifier : 4 */
245 atomic_t t_ref; /* ticket reference count : 4 */
246 int t_curr_res; /* current reservation in bytes : 4 */
247 int t_unit_res; /* unit reservation in bytes : 4 */
248 char t_ocnt; /* original count : 1 */
249 char t_cnt; /* current count : 1 */
250 char t_clientid; /* who does this belong to; : 1 */
251 char t_flags; /* properties of reservation : 1 */
252 uint t_trans_type; /* transaction type : 4 */
253
254 /* reservation array fields */
255 uint t_res_num; /* num in array : 4 */
256 uint t_res_num_ophdrs; /* num op hdrs : 4 */
257 uint t_res_arr_sum; /* array sum : 4 */
258 uint t_res_o_flow; /* sum overflow : 4 */
259 xlog_res_t t_res_arr[XLOG_TIC_LEN_MAX]; /* array of res : 8 * 15 */
260} xlog_ticket_t;
261
262#endif
263
264
265typedef struct xlog_op_header {
266 __be32 oh_tid; /* transaction id of operation : 4 b */
267 __be32 oh_len; /* bytes in data region : 4 b */
268 __u8 oh_clientid; /* who sent me this : 1 b */
269 __u8 oh_flags; /* : 1 b */
270 __u16 oh_res2; /* 32 bit align : 2 b */
271} xlog_op_header_t;
272
273
274/* valid values for h_fmt */
275#define XLOG_FMT_UNKNOWN 0
276#define XLOG_FMT_LINUX_LE 1
277#define XLOG_FMT_LINUX_BE 2
278#define XLOG_FMT_IRIX_BE 3
279
280/* our fmt */
281#ifdef XFS_NATIVE_HOST
282#define XLOG_FMT XLOG_FMT_LINUX_BE
283#else
284#define XLOG_FMT XLOG_FMT_LINUX_LE
285#endif
286
287typedef struct xlog_rec_header {
288 __be32 h_magicno; /* log record (LR) identifier : 4 */
289 __be32 h_cycle; /* write cycle of log : 4 */
290 __be32 h_version; /* LR version : 4 */
291 __be32 h_len; /* len in bytes; should be 64-bit aligned: 4 */
292 __be64 h_lsn; /* lsn of this LR : 8 */
293 __be64 h_tail_lsn; /* lsn of 1st LR w/ buffers not committed: 8 */
294 __be32 h_chksum; /* may not be used; non-zero if used : 4 */
295 __be32 h_prev_block; /* block number to previous LR : 4 */
296 __be32 h_num_logops; /* number of log operations in this LR : 4 */
297 __be32 h_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE];
298 /* new fields */
299 __be32 h_fmt; /* format of log record : 4 */
300 uuid_t h_fs_uuid; /* uuid of FS : 16 */
301 __be32 h_size; /* iclog size : 4 */
302} xlog_rec_header_t;
303
304typedef struct xlog_rec_ext_header {
305 __be32 xh_cycle; /* write cycle of log : 4 */
306 __be32 xh_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE]; /* : 256 */
307} xlog_rec_ext_header_t;
308
309#ifdef __KERNEL__
310
311/*
312 * Quite misnamed, because this union lays out the actual on-disk log buffer.
313 */
314typedef union xlog_in_core2 {
315 xlog_rec_header_t hic_header;
316 xlog_rec_ext_header_t hic_xheader;
317 char hic_sector[XLOG_HEADER_SIZE];
318} xlog_in_core_2_t;
319
320/*
321 * - A log record header is 512 bytes. There is plenty of room to grow the
322 * xlog_rec_header_t into the reserved space.
323 * - ic_data follows, so a write to disk can start at the beginning of
324 * the iclog.
325 * - ic_forcewait is used to implement synchronous forcing of the iclog to disk.
326 * - ic_next is the pointer to the next iclog in the ring.
327 * - ic_bp is a pointer to the buffer used to write this incore log to disk.
328 * - ic_log is a pointer back to the global log structure.
329 * - ic_callback is a linked list of callback function/argument pairs to be
330 * called after an iclog finishes writing.
331 * - ic_size is the full size of the header plus data.
332 * - ic_offset is the current number of bytes written to in this iclog.
333 * - ic_refcnt is bumped when someone is writing to the log.
334 * - ic_state is the state of the iclog.
335 *
336 * Because of cacheline contention on large machines, we need to separate
337 * various resources onto different cachelines. To start with, make the
338 * structure cacheline aligned. The following fields can be contended on
339 * by independent processes:
340 *
341 * - ic_callback_*
342 * - ic_refcnt
343 * - fields protected by the global l_icloglock
344 *
345 * so we need to ensure that these fields are located in separate cachelines.
346 * We'll put all the read-only and l_icloglock fields in the first cacheline,
347 * and move everything else out to subsequent cachelines.
348 */
349typedef struct xlog_in_core {
350 wait_queue_head_t ic_force_wait;
351 wait_queue_head_t ic_write_wait;
352 struct xlog_in_core *ic_next;
353 struct xlog_in_core *ic_prev;
354 struct xfs_buf *ic_bp;
355 struct xlog *ic_log;
356 int ic_size;
357 int ic_offset;
358 int ic_bwritecnt;
359 unsigned short ic_state;
360 char *ic_datap; /* pointer to iclog data */
361
362 /* Callback structures need their own cacheline */
363 spinlock_t ic_callback_lock ____cacheline_aligned_in_smp;
364 xfs_log_callback_t *ic_callback;
365 xfs_log_callback_t **ic_callback_tail;
366
367 /* reference counts need their own cacheline */
368 atomic_t ic_refcnt ____cacheline_aligned_in_smp;
369 xlog_in_core_2_t *ic_data;
370#define ic_header ic_data->hic_header
371} xlog_in_core_t;
372
373/*
374 * The CIL context is used to aggregate per-transaction details as well be
375 * passed to the iclog for checkpoint post-commit processing. After being
376 * passed to the iclog, another context needs to be allocated for tracking the
377 * next set of transactions to be aggregated into a checkpoint.
378 */
379struct xfs_cil;
380
381struct xfs_cil_ctx {
382 struct xfs_cil *cil;
383 xfs_lsn_t sequence; /* chkpt sequence # */
384 xfs_lsn_t start_lsn; /* first LSN of chkpt commit */
385 xfs_lsn_t commit_lsn; /* chkpt commit record lsn */
386 struct xlog_ticket *ticket; /* chkpt ticket */
387 int nvecs; /* number of regions */
388 int space_used; /* aggregate size of regions */
389 struct list_head busy_extents; /* busy extents in chkpt */
390 struct xfs_log_vec *lv_chain; /* logvecs being pushed */
391 xfs_log_callback_t log_cb; /* completion callback hook. */
392 struct list_head committing; /* ctx committing list */
393};
394
395/*
396 * Committed Item List structure
397 *
398 * This structure is used to track log items that have been committed but not
399 * yet written into the log. It is used only when the delayed logging mount
400 * option is enabled.
401 *
402 * This structure tracks the list of committing checkpoint contexts so
403 * we can avoid the problem of having to hold out new transactions during a
404 * flush until we have a the commit record LSN of the checkpoint. We can
405 * traverse the list of committing contexts in xlog_cil_push_lsn() to find a
406 * sequence match and extract the commit LSN directly from there. If the
407 * checkpoint is still in the process of committing, we can block waiting for
408 * the commit LSN to be determined as well. This should make synchronous
409 * operations almost as efficient as the old logging methods.
410 */
411struct xfs_cil {
412 struct xlog *xc_log;
413 struct list_head xc_cil;
414 spinlock_t xc_cil_lock;
415 struct xfs_cil_ctx *xc_ctx;
416 struct rw_semaphore xc_ctx_lock;
417 struct list_head xc_committing;
418 wait_queue_head_t xc_commit_wait;
419 xfs_lsn_t xc_current_sequence;
420 struct work_struct xc_push_work;
421 xfs_lsn_t xc_push_seq;
422};
423
424/*
425 * The amount of log space we allow the CIL to aggregate is difficult to size.
426 * Whatever we choose, we have to make sure we can get a reservation for the
427 * log space effectively, that it is large enough to capture sufficient
428 * relogging to reduce log buffer IO significantly, but it is not too large for
429 * the log or induces too much latency when writing out through the iclogs. We
430 * track both space consumed and the number of vectors in the checkpoint
431 * context, so we need to decide which to use for limiting.
432 *
433 * Every log buffer we write out during a push needs a header reserved, which
434 * is at least one sector and more for v2 logs. Hence we need a reservation of
435 * at least 512 bytes per 32k of log space just for the LR headers. That means
436 * 16KB of reservation per megabyte of delayed logging space we will consume,
437 * plus various headers. The number of headers will vary based on the num of
438 * io vectors, so limiting on a specific number of vectors is going to result
439 * in transactions of varying size. IOWs, it is more consistent to track and
440 * limit space consumed in the log rather than by the number of objects being
441 * logged in order to prevent checkpoint ticket overruns.
442 *
443 * Further, use of static reservations through the log grant mechanism is
444 * problematic. It introduces a lot of complexity (e.g. reserve grant vs write
445 * grant) and a significant deadlock potential because regranting write space
446 * can block on log pushes. Hence if we have to regrant log space during a log
447 * push, we can deadlock.
448 *
449 * However, we can avoid this by use of a dynamic "reservation stealing"
450 * technique during transaction commit whereby unused reservation space in the
451 * transaction ticket is transferred to the CIL ctx commit ticket to cover the
452 * space needed by the checkpoint transaction. This means that we never need to
453 * specifically reserve space for the CIL checkpoint transaction, nor do we
454 * need to regrant space once the checkpoint completes. This also means the
455 * checkpoint transaction ticket is specific to the checkpoint context, rather
456 * than the CIL itself.
457 *
458 * With dynamic reservations, we can effectively make up arbitrary limits for
459 * the checkpoint size so long as they don't violate any other size rules.
460 * Recovery imposes a rule that no transaction exceed half the log, so we are
461 * limited by that. Furthermore, the log transaction reservation subsystem
462 * tries to keep 25% of the log free, so we need to keep below that limit or we
463 * risk running out of free log space to start any new transactions.
464 *
465 * In order to keep background CIL push efficient, we will set a lower
466 * threshold at which background pushing is attempted without blocking current
467 * transaction commits. A separate, higher bound defines when CIL pushes are
468 * enforced to ensure we stay within our maximum checkpoint size bounds.
469 * threshold, yet give us plenty of space for aggregation on large logs.
470 */
471#define XLOG_CIL_SPACE_LIMIT(log) (log->l_logsize >> 3)
472#define XLOG_CIL_HARD_SPACE_LIMIT(log) (3 * (log->l_logsize >> 4))
473
474/*
475 * ticket grant locks, queues and accounting have their own cachlines
476 * as these are quite hot and can be operated on concurrently.
477 */
478struct xlog_grant_head {
479 spinlock_t lock ____cacheline_aligned_in_smp;
480 struct list_head waiters;
481 atomic64_t grant;
482};
483
484/*
485 * The reservation head lsn is not made up of a cycle number and block number.
486 * Instead, it uses a cycle number and byte number. Logs don't expect to
487 * overflow 31 bits worth of byte offset, so using a byte number will mean
488 * that round off problems won't occur when releasing partial reservations.
489 */
490typedef struct xlog {
491 /* The following fields don't need locking */
492 struct xfs_mount *l_mp; /* mount point */
493 struct xfs_ail *l_ailp; /* AIL log is working with */
494 struct xfs_cil *l_cilp; /* CIL log is working with */
495 struct xfs_buf *l_xbuf; /* extra buffer for log
496 * wrapping */
497 struct xfs_buftarg *l_targ; /* buftarg of log */
498 uint l_flags;
499 uint l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
500 struct list_head *l_buf_cancel_table;
501 int l_iclog_hsize; /* size of iclog header */
502 int l_iclog_heads; /* # of iclog header sectors */
503 uint l_sectBBsize; /* sector size in BBs (2^n) */
504 int l_iclog_size; /* size of log in bytes */
505 int l_iclog_size_log; /* log power size of log */
506 int l_iclog_bufs; /* number of iclog buffers */
507 xfs_daddr_t l_logBBstart; /* start block of log */
508 int l_logsize; /* size of log in bytes */
509 int l_logBBsize; /* size of log in BB chunks */
510
511 /* The following block of fields are changed while holding icloglock */
512 wait_queue_head_t l_flush_wait ____cacheline_aligned_in_smp;
513 /* waiting for iclog flush */
514 int l_covered_state;/* state of "covering disk
515 * log entries" */
516 xlog_in_core_t *l_iclog; /* head log queue */
517 spinlock_t l_icloglock; /* grab to change iclog state */
518 int l_curr_cycle; /* Cycle number of log writes */
519 int l_prev_cycle; /* Cycle number before last
520 * block increment */
521 int l_curr_block; /* current logical log block */
522 int l_prev_block; /* previous logical log block */
523
524 /*
525 * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
526 * read without needing to hold specific locks. To avoid operations
527 * contending with other hot objects, place each of them on a separate
528 * cacheline.
529 */
530 /* lsn of last LR on disk */
531 atomic64_t l_last_sync_lsn ____cacheline_aligned_in_smp;
532 /* lsn of 1st LR with unflushed * buffers */
533 atomic64_t l_tail_lsn ____cacheline_aligned_in_smp;
534
535 struct xlog_grant_head l_reserve_head;
536 struct xlog_grant_head l_write_head;
537
538 /* The following field are used for debugging; need to hold icloglock */
539#ifdef DEBUG
540 char *l_iclog_bak[XLOG_MAX_ICLOGS];
541#endif
542
543} xlog_t;
544
545#define XLOG_BUF_CANCEL_BUCKET(log, blkno) \
546 ((log)->l_buf_cancel_table + ((__uint64_t)blkno % XLOG_BC_TABLE_SIZE))
547
548#define XLOG_FORCED_SHUTDOWN(log) ((log)->l_flags & XLOG_IO_ERROR)
549
550/* common routines */
551extern int xlog_recover(xlog_t *log);
552extern int xlog_recover_finish(xlog_t *log);
553extern void xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int);
554
555extern kmem_zone_t *xfs_log_ticket_zone;
556struct xlog_ticket *
557xlog_ticket_alloc(
558 struct xlog *log,
559 int unit_bytes,
560 int count,
561 char client,
562 bool permanent,
563 xfs_km_flags_t alloc_flags);
564
565
566static inline void
567xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes)
568{
569 *ptr += bytes;
570 *len -= bytes;
571 *off += bytes;
572}
573
574void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
575int
576xlog_write(
577 struct xlog *log,
578 struct xfs_log_vec *log_vector,
579 struct xlog_ticket *tic,
580 xfs_lsn_t *start_lsn,
581 struct xlog_in_core **commit_iclog,
582 uint flags);
583
584/*
585 * When we crack an atomic LSN, we sample it first so that the value will not
586 * change while we are cracking it into the component values. This means we
587 * will always get consistent component values to work from. This should always
588 * be used to sample and crack LSNs that are stored and updated in atomic
589 * variables.
590 */
591static inline void
592xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
593{
594 xfs_lsn_t val = atomic64_read(lsn);
595
596 *cycle = CYCLE_LSN(val);
597 *block = BLOCK_LSN(val);
598}
599
600/*
601 * Calculate and assign a value to an atomic LSN variable from component pieces.
602 */
603static inline void
604xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
605{
606 atomic64_set(lsn, xlog_assign_lsn(cycle, block));
607}
608
609/*
610 * When we crack the grant head, we sample it first so that the value will not
611 * change while we are cracking it into the component values. This means we
612 * will always get consistent component values to work from.
613 */
614static inline void
615xlog_crack_grant_head_val(int64_t val, int *cycle, int *space)
616{
617 *cycle = val >> 32;
618 *space = val & 0xffffffff;
619}
620
621static inline void
622xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
623{
624 xlog_crack_grant_head_val(atomic64_read(head), cycle, space);
625}
626
627static inline int64_t
628xlog_assign_grant_head_val(int cycle, int space)
629{
630 return ((int64_t)cycle << 32) | space;
631}
632
633static inline void
634xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
635{
636 atomic64_set(head, xlog_assign_grant_head_val(cycle, space));
637}
638
639/*
640 * Committed Item List interfaces
641 */
642int
643xlog_cil_init(struct xlog *log);
644void
645xlog_cil_init_post_recovery(struct xlog *log);
646void
647xlog_cil_destroy(struct xlog *log);
648
649/*
650 * CIL force routines
651 */
652xfs_lsn_t
653xlog_cil_force_lsn(
654 struct xlog *log,
655 xfs_lsn_t sequence);
656
657static inline void
658xlog_cil_force(struct xlog *log)
659{
660 xlog_cil_force_lsn(log, log->l_cilp->xc_current_sequence);
661}
662
663/*
664 * Unmount record type is used as a pseudo transaction type for the ticket.
665 * It's value must be outside the range of XFS_TRANS_* values.
666 */
667#define XLOG_UNMOUNT_REC_TYPE (-1U)
668
669/*
670 * Wrapper function for waiting on a wait queue serialised against wakeups
671 * by a spinlock. This matches the semantics of all the wait queues used in the
672 * log code.
673 */
674static inline void xlog_wait(wait_queue_head_t *wq, spinlock_t *lock)
675{
676 DECLARE_WAITQUEUE(wait, current);
677
678 add_wait_queue_exclusive(wq, &wait);
679 __set_current_state(TASK_UNINTERRUPTIBLE);
680 spin_unlock(lock);
681 schedule();
682 remove_wait_queue(wq, &wait);
683}
684#endif /* __KERNEL__ */
685
686#endif /* __XFS_LOG_PRIV_H__ */
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
9struct xfs_buf;
10struct xlog;
11struct xlog_ticket;
12struct 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 */
26static 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 */
34enum 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
145typedef 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 */
184typedef 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 */
216struct xfs_cil;
217
218struct 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 */
239struct 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 */
262struct 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 */
383struct 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 */
395struct 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
462static inline bool
463xlog_recovery_needed(struct xlog *log)
464{
465 return test_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
466}
467
468static inline bool
469xlog_in_recovery(struct xlog *log)
470{
471 return test_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
472}
473
474static inline bool
475xlog_is_shutdown(struct xlog *log)
476{
477 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 */
484static inline void
485xlog_shutdown_wait(
486 struct xlog *log)
487{
488 wait_var_event(&log->l_opstate, xlog_is_shutdown(log));
489}
490
491/* common routines */
492extern int
493xlog_recover(
494 struct xlog *log);
495extern int
496xlog_recover_finish(
497 struct xlog *log);
498extern void
499xlog_recover_cancel(struct xlog *);
500
501extern __le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead,
502 char *dp, int size);
503
504extern struct kmem_cache *xfs_log_ticket_cache;
505struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes,
506 int count, bool permanent);
507
508void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
509void xlog_print_trans(struct xfs_trans *);
510int xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx,
511 struct list_head *lv_chain, struct xlog_ticket *tic,
512 uint32_t len);
513void xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket);
514void xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket);
515
516void xlog_state_switch_iclogs(struct xlog *log, struct xlog_in_core *iclog,
517 int eventual_size);
518int 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 */
528static inline void
529xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
530{
531 xfs_lsn_t val = atomic64_read(lsn);
532
533 *cycle = CYCLE_LSN(val);
534 *block = BLOCK_LSN(val);
535}
536
537/*
538 * Calculate and assign a value to an atomic LSN variable from component pieces.
539 */
540static inline void
541xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
542{
543 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 */
551static inline void
552xlog_crack_grant_head_val(int64_t val, int *cycle, int *space)
553{
554 *cycle = val >> 32;
555 *space = val & 0xffffffff;
556}
557
558static inline void
559xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
560{
561 xlog_crack_grant_head_val(atomic64_read(head), cycle, space);
562}
563
564static inline int64_t
565xlog_assign_grant_head_val(int cycle, int space)
566{
567 return ((int64_t)cycle << 32) | space;
568}
569
570static inline void
571xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
572{
573 atomic64_set(head, xlog_assign_grant_head_val(cycle, space));
574}
575
576/*
577 * Committed Item List interfaces
578 */
579int xlog_cil_init(struct xlog *log);
580void xlog_cil_init_post_recovery(struct xlog *log);
581void xlog_cil_destroy(struct xlog *log);
582bool xlog_cil_empty(struct xlog *log);
583void xlog_cil_commit(struct xlog *log, struct xfs_trans *tp,
584 xfs_csn_t *commit_seq, bool regrant);
585void 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 */
592void xlog_cil_flush(struct xlog *log);
593xfs_lsn_t xlog_cil_force_seq(struct xlog *log, xfs_csn_t sequence);
594
595static inline void
596xlog_cil_force(struct xlog *log)
597{
598 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 */
606static inline void
607xlog_wait(
608 struct wait_queue_head *wq,
609 struct spinlock *lock)
610 __releases(lock)
611{
612 DECLARE_WAITQUEUE(wait, current);
613
614 add_wait_queue_exclusive(wq, &wait);
615 __set_current_state(TASK_UNINTERRUPTIBLE);
616 spin_unlock(lock);
617 schedule();
618 remove_wait_queue(wq, &wait);
619}
620
621int 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 */
629static inline bool
630xlog_valid_lsn(
631 struct xlog *log,
632 xfs_lsn_t lsn)
633{
634 int cur_cycle;
635 int cur_block;
636 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 cur_cycle = READ_ONCE(log->l_curr_cycle);
651 smp_rmb();
652 cur_block = READ_ONCE(log->l_curr_block);
653
654 if ((CYCLE_LSN(lsn) > cur_cycle) ||
655 (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 spin_lock(&log->l_icloglock);
662 cur_cycle = log->l_curr_cycle;
663 cur_block = log->l_curr_block;
664 spin_unlock(&log->l_icloglock);
665
666 if ((CYCLE_LSN(lsn) > cur_cycle) ||
667 (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block))
668 valid = false;
669 }
670
671 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 */
690static inline void *
691xlog_kvmalloc(
692 size_t buf_size)
693{
694 gfp_t flags = GFP_KERNEL;
695 void *p;
696
697 flags &= ~__GFP_DIRECT_RECLAIM;
698 flags |= __GFP_NOWARN | __GFP_NORETRY;
699 do {
700 p = kmalloc(buf_size, flags);
701 if (!p)
702 p = vmalloc(buf_size);
703 } while (!p);
704
705 return p;
706}
707
708/*
709 * CIL CPU dead notifier
710 */
711void xlog_cil_pcp_dead(struct xlog *log, unsigned int cpu);
712
713#endif /* __XFS_LOG_PRIV_H__ */