1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
6 #ifndef __XFS_LOG_PRIV_H__
7 #define __XFS_LOG_PRIV_H__
15 * get client id from packed copy.
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.
21 * later on this four byte chunk is treated as an int and the
22 * client id is pulled out.
24 * this has endian issues, of course.
26 static inline uint
xlog_get_client_id(__be32 i
)
28 return be32_to_cpu(i
) >> 24;
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 */
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" }
54 #define XLOG_ICL_NEED_FLUSH (1u << 0) /* iclog needs REQ_PREFLUSH */
55 #define XLOG_ICL_NEED_FUA (1u << 1) /* iclog needs REQ_FUA */
57 #define XLOG_ICL_STRINGS \
58 { XLOG_ICL_NEED_FLUSH, "XLOG_ICL_NEED_FLUSH" }, \
59 { XLOG_ICL_NEED_FUA, "XLOG_ICL_NEED_FUA" }
65 #define XLOG_TIC_PERM_RESERV (1u << 0) /* permanent reservation */
67 #define XLOG_TIC_FLAGS \
68 { XLOG_TIC_PERM_RESERV, "XLOG_TIC_PERM_RESERV" }
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
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.
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.
95 * These dummy transactions get committed when everything
96 * is idle (after there has been some activity).
98 * There are 5 states used to control this.
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
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.
110 * There are two places where we switch states:
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.
116 * 2.) When we finish writing the on-disk log (xlog_state_clean_log).
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.
124 * If we are in the DONE state and this was a write of the
125 * dummy transaction, we move to NEED2.
127 * If we are in the DONE2 state and this was a write of the
128 * dummy transaction, we move to IDLE.
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.
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
143 #define XLOG_COVER_OPS 5
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 */
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
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.
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:
178 * - fields protected by the global l_icloglock
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.
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
;
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
;
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
202 bool ic_fail_crc
: 1;
204 struct semaphore ic_sema
;
205 struct work_struct ic_end_io_work
;
207 struct bio_vec ic_bvec
[];
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.
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
;
237 * Per-cpu CIL tracking items
239 struct xlog_cil_pcp
{
241 uint32_t space_reserved
;
242 struct list_head busy_extents
;
243 struct list_head log_items
;
247 * Committed Item List structure
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
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.
264 unsigned long xc_flags
;
265 atomic_t xc_iclog_hdrs
;
266 struct workqueue_struct
*xc_push_wq
;
268 struct rw_semaphore xc_ctx_lock ____cacheline_aligned_in_smp
;
269 struct xfs_cil_ctx
*xc_ctx
;
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 */
280 void __percpu
*xc_pcp
; /* percpu CIL structures */
281 #ifdef CONFIG_HOTPLUG_CPU
282 struct list_head xc_pcp_list
;
284 } ____cacheline_aligned_in_smp
;
286 /* xc_flags bit values */
287 #define XLOG_CIL_EMPTY 1
288 #define XLOG_CIL_PCP_SPACE 2
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.
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.
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.
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.
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.
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
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
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.
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
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.
373 #define XLOG_CIL_SPACE_LIMIT(log) \
374 min_t(int, (log)->l_logsize >> 3, BBTOB(XLOG_TOTAL_REC_SHIFT(log)) << 4)
376 #define XLOG_CIL_BLOCKING_SPACE_LIMIT(log) \
377 (XLOG_CIL_SPACE_LIMIT(log) * 2)
380 * ticket grant locks, queues and accounting have their own cachlines
381 * as these are quite hot and can be operated on concurrently.
383 struct xlog_grant_head
{
384 spinlock_t lock ____cacheline_aligned_in_smp
;
385 struct list_head waiters
;
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.
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 */
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
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
425 int l_curr_block
; /* current logical log block */
426 int l_prev_block
; /* previous logical log block */
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
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
;
439 struct xlog_grant_head l_reserve_head
;
440 struct xlog_grant_head l_write_head
;
442 struct xfs_kobj l_kobj
;
444 /* log recovery lsn tracking (for buffer submission */
445 xfs_lsn_t l_recovery_lsn
;
447 uint32_t l_iclog_roundoff
;/* padding roundoff */
449 /* Users of log incompat features should take a read lock. */
450 struct rw_semaphore l_incompat_users
;
454 * Bits for operational state
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
460 #define XLOG_TAIL_WARN 3 /* log tail verify warning issued */
463 xlog_recovery_needed(struct xlog
*log
)
465 return test_bit(XLOG_RECOVERY_NEEDED
, &log
->l_opstate
);
469 xlog_in_recovery(struct xlog
*log
)
471 return test_bit(XLOG_ACTIVE_RECOVERY
, &log
->l_opstate
);
475 xlog_is_shutdown(struct xlog
*log
)
477 return test_bit(XLOG_IO_ERROR
, &log
->l_opstate
);
481 * Wait until the xlog_force_shutdown() has marked the log as shut down
482 * so xlog_is_shutdown() will always return true.
488 wait_var_event(&log
->l_opstate
, xlog_is_shutdown(log
));
491 /* common routines */
499 xlog_recover_cancel(struct xlog
*);
501 extern __le32
xlog_cksum(struct xlog
*log
, struct xlog_rec_header
*rhead
,
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
);
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
,
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
);
516 void xlog_state_switch_iclogs(struct xlog
*log
, struct xlog_in_core
*iclog
,
518 int xlog_state_release_iclog(struct xlog
*log
, struct xlog_in_core
*iclog
,
519 struct xlog_ticket
*ticket
);
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
529 xlog_crack_atomic_lsn(atomic64_t
*lsn
, uint
*cycle
, uint
*block
)
531 xfs_lsn_t val
= atomic64_read(lsn
);
533 *cycle
= CYCLE_LSN(val
);
534 *block
= BLOCK_LSN(val
);
538 * Calculate and assign a value to an atomic LSN variable from component pieces.
541 xlog_assign_atomic_lsn(atomic64_t
*lsn
, uint cycle
, uint block
)
543 atomic64_set(lsn
, xlog_assign_lsn(cycle
, block
));
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.
552 xlog_crack_grant_head_val(int64_t val
, int *cycle
, int *space
)
555 *space
= val
& 0xffffffff;
559 xlog_crack_grant_head(atomic64_t
*head
, int *cycle
, int *space
)
561 xlog_crack_grant_head_val(atomic64_read(head
), cycle
, space
);
564 static inline int64_t
565 xlog_assign_grant_head_val(int cycle
, int space
)
567 return ((int64_t)cycle
<< 32) | space
;
571 xlog_assign_grant_head(atomic64_t
*head
, int cycle
, int space
)
573 atomic64_set(head
, xlog_assign_grant_head_val(cycle
, space
));
577 * Committed Item List interfaces
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
);
592 void xlog_cil_flush(struct xlog
*log
);
593 xfs_lsn_t
xlog_cil_force_seq(struct xlog
*log
, xfs_csn_t sequence
);
596 xlog_cil_force(struct xlog
*log
)
598 xlog_cil_force_seq(log
, log
->l_cilp
->xc_current_sequence
);
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
608 struct wait_queue_head
*wq
,
609 struct spinlock
*lock
)
612 DECLARE_WAITQUEUE(wait
, current
);
614 add_wait_queue_exclusive(wq
, &wait
);
615 __set_current_state(TASK_UNINTERRUPTIBLE
);
618 remove_wait_queue(wq
, &wait
);
621 int xlog_wait_on_iclog(struct xlog_in_core
*iclog
);
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
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
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.
650 cur_cycle
= READ_ONCE(log
->l_curr_cycle
);
652 cur_block
= READ_ONCE(log
->l_curr_block
);
654 if ((CYCLE_LSN(lsn
) > cur_cycle
) ||
655 (CYCLE_LSN(lsn
) == cur_cycle
&& BLOCK_LSN(lsn
) > cur_block
)) {
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
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
);
666 if ((CYCLE_LSN(lsn
) > cur_cycle
) ||
667 (CYCLE_LSN(lsn
) == cur_cycle
&& BLOCK_LSN(lsn
) > cur_block
))
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.
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
694 gfp_t flags
= GFP_KERNEL
;
697 flags
&= ~__GFP_DIRECT_RECLAIM
;
698 flags
|= __GFP_NOWARN
| __GFP_NORETRY
;
700 p
= kmalloc(buf_size
, flags
);
702 p
= vmalloc(buf_size
);
709 * CIL CPU dead notifier
711 void xlog_cil_pcp_dead(struct xlog
*log
, unsigned int cpu
);
713 #endif /* __XFS_LOG_PRIV_H__ */