xref: /openbmc/linux/fs/xfs/xfs_log_priv.h (revision 22fd411a)
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 
21 struct xfs_buf;
22 struct log;
23 struct xlog_ticket;
24 struct 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 
56 static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
57 {
58 	return ((xfs_lsn_t)cycle << 32) | block;
59 }
60 
61 static 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  */
85 static inline uint xlog_get_client_id(__be32 i)
86 {
87 	return be32_to_cpu(i) >> 24;
88 }
89 
90 #define xlog_panic(args...)	cmn_err(CE_PANIC, ## args)
91 #define xlog_exit(args...)	cmn_err(CE_PANIC, ## args)
92 #define xlog_warn(args...)	cmn_err(CE_WARN, ## args)
93 
94 /*
95  * In core log state
96  */
97 #define XLOG_STATE_ACTIVE    0x0001 /* Current IC log being written to */
98 #define XLOG_STATE_WANT_SYNC 0x0002 /* Want to sync this iclog; no more writes */
99 #define XLOG_STATE_SYNCING   0x0004 /* This IC log is syncing */
100 #define XLOG_STATE_DONE_SYNC 0x0008 /* Done syncing to disk */
101 #define XLOG_STATE_DO_CALLBACK \
102 			     0x0010 /* Process callback functions */
103 #define XLOG_STATE_CALLBACK  0x0020 /* Callback functions now */
104 #define XLOG_STATE_DIRTY     0x0040 /* Dirty IC log, not ready for ACTIVE status*/
105 #define XLOG_STATE_IOERROR   0x0080 /* IO error happened in sync'ing log */
106 #define XLOG_STATE_ALL	     0x7FFF /* All possible valid flags */
107 #define XLOG_STATE_NOTUSED   0x8000 /* This IC log not being used */
108 #endif	/* __KERNEL__ */
109 
110 /*
111  * Flags to log operation header
112  *
113  * The first write of a new transaction will be preceded with a start
114  * record, XLOG_START_TRANS.  Once a transaction is committed, a commit
115  * record is written, XLOG_COMMIT_TRANS.  If a single region can not fit into
116  * the remainder of the current active in-core log, it is split up into
117  * multiple regions.  Each partial region will be marked with a
118  * XLOG_CONTINUE_TRANS until the last one, which gets marked with XLOG_END_TRANS.
119  *
120  */
121 #define XLOG_START_TRANS	0x01	/* Start a new transaction */
122 #define XLOG_COMMIT_TRANS	0x02	/* Commit this transaction */
123 #define XLOG_CONTINUE_TRANS	0x04	/* Cont this trans into new region */
124 #define XLOG_WAS_CONT_TRANS	0x08	/* Cont this trans into new region */
125 #define XLOG_END_TRANS		0x10	/* End a continued transaction */
126 #define XLOG_UNMOUNT_TRANS	0x20	/* Unmount a filesystem transaction */
127 
128 #ifdef __KERNEL__
129 /*
130  * Flags to log ticket
131  */
132 #define XLOG_TIC_INITED		0x1	/* has been initialized */
133 #define XLOG_TIC_PERM_RESERV	0x2	/* permanent reservation */
134 
135 #define XLOG_TIC_FLAGS \
136 	{ XLOG_TIC_INITED,	"XLOG_TIC_INITED" }, \
137 	{ XLOG_TIC_PERM_RESERV,	"XLOG_TIC_PERM_RESERV" }
138 
139 #endif	/* __KERNEL__ */
140 
141 #define XLOG_UNMOUNT_TYPE	0x556e	/* Un for Unmount */
142 
143 /*
144  * Flags for log structure
145  */
146 #define XLOG_CHKSUM_MISMATCH	0x1	/* used only during recovery */
147 #define XLOG_ACTIVE_RECOVERY	0x2	/* in the middle of recovery */
148 #define	XLOG_RECOVERY_NEEDED	0x4	/* log was recovered */
149 #define XLOG_IO_ERROR		0x8	/* log hit an I/O error, and being
150 					   shutdown */
151 
152 #ifdef __KERNEL__
153 /*
154  * Below are states for covering allocation transactions.
155  * By covering, we mean changing the h_tail_lsn in the last on-disk
156  * log write such that no allocation transactions will be re-done during
157  * recovery after a system crash. Recovery starts at the last on-disk
158  * log write.
159  *
160  * These states are used to insert dummy log entries to cover
161  * space allocation transactions which can undo non-transactional changes
162  * after a crash. Writes to a file with space
163  * already allocated do not result in any transactions. Allocations
164  * might include space beyond the EOF. So if we just push the EOF a
165  * little, the last transaction for the file could contain the wrong
166  * size. If there is no file system activity, after an allocation
167  * transaction, and the system crashes, the allocation transaction
168  * will get replayed and the file will be truncated. This could
169  * be hours/days/... after the allocation occurred.
170  *
171  * The fix for this is to do two dummy transactions when the
172  * system is idle. We need two dummy transaction because the h_tail_lsn
173  * in the log record header needs to point beyond the last possible
174  * non-dummy transaction. The first dummy changes the h_tail_lsn to
175  * the first transaction before the dummy. The second dummy causes
176  * h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn.
177  *
178  * These dummy transactions get committed when everything
179  * is idle (after there has been some activity).
180  *
181  * There are 5 states used to control this.
182  *
183  *  IDLE -- no logging has been done on the file system or
184  *		we are done covering previous transactions.
185  *  NEED -- logging has occurred and we need a dummy transaction
186  *		when the log becomes idle.
187  *  DONE -- we were in the NEED state and have committed a dummy
188  *		transaction.
189  *  NEED2 -- we detected that a dummy transaction has gone to the
190  *		on disk log with no other transactions.
191  *  DONE2 -- we committed a dummy transaction when in the NEED2 state.
192  *
193  * There are two places where we switch states:
194  *
195  * 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2.
196  *	We commit the dummy transaction and switch to DONE or DONE2,
197  *	respectively. In all other states, we don't do anything.
198  *
199  * 2.) When we finish writing the on-disk log (xlog_state_clean_log).
200  *
201  *	No matter what state we are in, if this isn't the dummy
202  *	transaction going out, the next state is NEED.
203  *	So, if we aren't in the DONE or DONE2 states, the next state
204  *	is NEED. We can't be finishing a write of the dummy record
205  *	unless it was committed and the state switched to DONE or DONE2.
206  *
207  *	If we are in the DONE state and this was a write of the
208  *		dummy transaction, we move to NEED2.
209  *
210  *	If we are in the DONE2 state and this was a write of the
211  *		dummy transaction, we move to IDLE.
212  *
213  *
214  * Writing only one dummy transaction can get appended to
215  * one file space allocation. When this happens, the log recovery
216  * code replays the space allocation and a file could be truncated.
217  * This is why we have the NEED2 and DONE2 states before going idle.
218  */
219 
220 #define XLOG_STATE_COVER_IDLE	0
221 #define XLOG_STATE_COVER_NEED	1
222 #define XLOG_STATE_COVER_DONE	2
223 #define XLOG_STATE_COVER_NEED2	3
224 #define XLOG_STATE_COVER_DONE2	4
225 
226 #define XLOG_COVER_OPS		5
227 
228 
229 /* Ticket reservation region accounting */
230 #define XLOG_TIC_LEN_MAX	15
231 
232 /*
233  * Reservation region
234  * As would be stored in xfs_log_iovec but without the i_addr which
235  * we don't care about.
236  */
237 typedef struct xlog_res {
238 	uint	r_len;	/* region length		:4 */
239 	uint	r_type;	/* region's transaction type	:4 */
240 } xlog_res_t;
241 
242 typedef struct xlog_ticket {
243 	wait_queue_head_t  t_wait;	 /* ticket wait queue */
244 	struct list_head   t_queue;	 /* reserve/write queue */
245 	xlog_tid_t	   t_tid;	 /* transaction identifier	 : 4  */
246 	atomic_t	   t_ref;	 /* ticket reference count       : 4  */
247 	int		   t_curr_res;	 /* current reservation in bytes : 4  */
248 	int		   t_unit_res;	 /* unit reservation in bytes    : 4  */
249 	char		   t_ocnt;	 /* original count		 : 1  */
250 	char		   t_cnt;	 /* current count		 : 1  */
251 	char		   t_clientid;	 /* who does this belong to;	 : 1  */
252 	char		   t_flags;	 /* properties of reservation	 : 1  */
253 	uint		   t_trans_type; /* transaction type             : 4  */
254 
255         /* reservation array fields */
256 	uint		   t_res_num;                    /* num in array : 4 */
257 	uint		   t_res_num_ophdrs;		 /* num op hdrs  : 4 */
258 	uint		   t_res_arr_sum;		 /* array sum    : 4 */
259 	uint		   t_res_o_flow;		 /* sum overflow : 4 */
260 	xlog_res_t	   t_res_arr[XLOG_TIC_LEN_MAX];  /* array of res : 8 * 15 */
261 } xlog_ticket_t;
262 
263 #endif
264 
265 
266 typedef struct xlog_op_header {
267 	__be32	   oh_tid;	/* transaction id of operation	:  4 b */
268 	__be32	   oh_len;	/* bytes in data region		:  4 b */
269 	__u8	   oh_clientid;	/* who sent me this		:  1 b */
270 	__u8	   oh_flags;	/*				:  1 b */
271 	__u16	   oh_res2;	/* 32 bit align			:  2 b */
272 } xlog_op_header_t;
273 
274 
275 /* valid values for h_fmt */
276 #define XLOG_FMT_UNKNOWN  0
277 #define XLOG_FMT_LINUX_LE 1
278 #define XLOG_FMT_LINUX_BE 2
279 #define XLOG_FMT_IRIX_BE  3
280 
281 /* our fmt */
282 #ifdef XFS_NATIVE_HOST
283 #define XLOG_FMT XLOG_FMT_LINUX_BE
284 #else
285 #define XLOG_FMT XLOG_FMT_LINUX_LE
286 #endif
287 
288 typedef struct xlog_rec_header {
289 	__be32	  h_magicno;	/* log record (LR) identifier		:  4 */
290 	__be32	  h_cycle;	/* write cycle of log			:  4 */
291 	__be32	  h_version;	/* LR version				:  4 */
292 	__be32	  h_len;	/* len in bytes; should be 64-bit aligned: 4 */
293 	__be64	  h_lsn;	/* lsn of this LR			:  8 */
294 	__be64	  h_tail_lsn;	/* lsn of 1st LR w/ buffers not committed: 8 */
295 	__be32	  h_chksum;	/* may not be used; non-zero if used	:  4 */
296 	__be32	  h_prev_block; /* block number to previous LR		:  4 */
297 	__be32	  h_num_logops;	/* number of log operations in this LR	:  4 */
298 	__be32	  h_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE];
299 	/* new fields */
300 	__be32    h_fmt;        /* format of log record                 :  4 */
301 	uuid_t	  h_fs_uuid;    /* uuid of FS                           : 16 */
302 	__be32	  h_size;	/* iclog size				:  4 */
303 } xlog_rec_header_t;
304 
305 typedef struct xlog_rec_ext_header {
306 	__be32	  xh_cycle;	/* write cycle of log			: 4 */
307 	__be32	  xh_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE]; /*	: 256 */
308 } xlog_rec_ext_header_t;
309 
310 #ifdef __KERNEL__
311 
312 /*
313  * Quite misnamed, because this union lays out the actual on-disk log buffer.
314  */
315 typedef union xlog_in_core2 {
316 	xlog_rec_header_t	hic_header;
317 	xlog_rec_ext_header_t	hic_xheader;
318 	char			hic_sector[XLOG_HEADER_SIZE];
319 } xlog_in_core_2_t;
320 
321 /*
322  * - A log record header is 512 bytes.  There is plenty of room to grow the
323  *	xlog_rec_header_t into the reserved space.
324  * - ic_data follows, so a write to disk can start at the beginning of
325  *	the iclog.
326  * - ic_forcewait is used to implement synchronous forcing of the iclog to disk.
327  * - ic_next is the pointer to the next iclog in the ring.
328  * - ic_bp is a pointer to the buffer used to write this incore log to disk.
329  * - ic_log is a pointer back to the global log structure.
330  * - ic_callback is a linked list of callback function/argument pairs to be
331  *	called after an iclog finishes writing.
332  * - ic_size is the full size of the header plus data.
333  * - ic_offset is the current number of bytes written to in this iclog.
334  * - ic_refcnt is bumped when someone is writing to the log.
335  * - ic_state is the state of the iclog.
336  *
337  * Because of cacheline contention on large machines, we need to separate
338  * various resources onto different cachelines. To start with, make the
339  * structure cacheline aligned. The following fields can be contended on
340  * by independent processes:
341  *
342  *	- ic_callback_*
343  *	- ic_refcnt
344  *	- fields protected by the global l_icloglock
345  *
346  * so we need to ensure that these fields are located in separate cachelines.
347  * We'll put all the read-only and l_icloglock fields in the first cacheline,
348  * and move everything else out to subsequent cachelines.
349  */
350 typedef struct xlog_in_core {
351 	wait_queue_head_t	ic_force_wait;
352 	wait_queue_head_t	ic_write_wait;
353 	struct xlog_in_core	*ic_next;
354 	struct xlog_in_core	*ic_prev;
355 	struct xfs_buf		*ic_bp;
356 	struct log		*ic_log;
357 	int			ic_size;
358 	int			ic_offset;
359 	int			ic_bwritecnt;
360 	unsigned short		ic_state;
361 	char			*ic_datap;	/* pointer to iclog data */
362 
363 	/* Callback structures need their own cacheline */
364 	spinlock_t		ic_callback_lock ____cacheline_aligned_in_smp;
365 	xfs_log_callback_t	*ic_callback;
366 	xfs_log_callback_t	**ic_callback_tail;
367 
368 	/* reference counts need their own cacheline */
369 	atomic_t		ic_refcnt ____cacheline_aligned_in_smp;
370 	xlog_in_core_2_t	*ic_data;
371 #define ic_header	ic_data->hic_header
372 } xlog_in_core_t;
373 
374 /*
375  * The CIL context is used to aggregate per-transaction details as well be
376  * passed to the iclog for checkpoint post-commit processing.  After being
377  * passed to the iclog, another context needs to be allocated for tracking the
378  * next set of transactions to be aggregated into a checkpoint.
379  */
380 struct xfs_cil;
381 
382 struct xfs_cil_ctx {
383 	struct xfs_cil		*cil;
384 	xfs_lsn_t		sequence;	/* chkpt sequence # */
385 	xfs_lsn_t		start_lsn;	/* first LSN of chkpt commit */
386 	xfs_lsn_t		commit_lsn;	/* chkpt commit record lsn */
387 	struct xlog_ticket	*ticket;	/* chkpt ticket */
388 	int			nvecs;		/* number of regions */
389 	int			space_used;	/* aggregate size of regions */
390 	struct list_head	busy_extents;	/* busy extents in chkpt */
391 	struct xfs_log_vec	*lv_chain;	/* logvecs being pushed */
392 	xfs_log_callback_t	log_cb;		/* completion callback hook. */
393 	struct list_head	committing;	/* ctx committing list */
394 };
395 
396 /*
397  * Committed Item List structure
398  *
399  * This structure is used to track log items that have been committed but not
400  * yet written into the log. It is used only when the delayed logging mount
401  * option is enabled.
402  *
403  * This structure tracks the list of committing checkpoint contexts so
404  * we can avoid the problem of having to hold out new transactions during a
405  * flush until we have a the commit record LSN of the checkpoint. We can
406  * traverse the list of committing contexts in xlog_cil_push_lsn() to find a
407  * sequence match and extract the commit LSN directly from there. If the
408  * checkpoint is still in the process of committing, we can block waiting for
409  * the commit LSN to be determined as well. This should make synchronous
410  * operations almost as efficient as the old logging methods.
411  */
412 struct xfs_cil {
413 	struct log		*xc_log;
414 	struct list_head	xc_cil;
415 	spinlock_t		xc_cil_lock;
416 	struct xfs_cil_ctx	*xc_ctx;
417 	struct rw_semaphore	xc_ctx_lock;
418 	struct list_head	xc_committing;
419 	wait_queue_head_t	xc_commit_wait;
420 	xfs_lsn_t		xc_current_sequence;
421 };
422 
423 /*
424  * The amount of log space we allow the CIL to aggregate is difficult to size.
425  * Whatever we choose, we have to make sure we can get a reservation for the
426  * log space effectively, that it is large enough to capture sufficient
427  * relogging to reduce log buffer IO significantly, but it is not too large for
428  * the log or induces too much latency when writing out through the iclogs. We
429  * track both space consumed and the number of vectors in the checkpoint
430  * context, so we need to decide which to use for limiting.
431  *
432  * Every log buffer we write out during a push needs a header reserved, which
433  * is at least one sector and more for v2 logs. Hence we need a reservation of
434  * at least 512 bytes per 32k of log space just for the LR headers. That means
435  * 16KB of reservation per megabyte of delayed logging space we will consume,
436  * plus various headers.  The number of headers will vary based on the num of
437  * io vectors, so limiting on a specific number of vectors is going to result
438  * in transactions of varying size. IOWs, it is more consistent to track and
439  * limit space consumed in the log rather than by the number of objects being
440  * logged in order to prevent checkpoint ticket overruns.
441  *
442  * Further, use of static reservations through the log grant mechanism is
443  * problematic. It introduces a lot of complexity (e.g. reserve grant vs write
444  * grant) and a significant deadlock potential because regranting write space
445  * can block on log pushes. Hence if we have to regrant log space during a log
446  * push, we can deadlock.
447  *
448  * However, we can avoid this by use of a dynamic "reservation stealing"
449  * technique during transaction commit whereby unused reservation space in the
450  * transaction ticket is transferred to the CIL ctx commit ticket to cover the
451  * space needed by the checkpoint transaction. This means that we never need to
452  * specifically reserve space for the CIL checkpoint transaction, nor do we
453  * need to regrant space once the checkpoint completes. This also means the
454  * checkpoint transaction ticket is specific to the checkpoint context, rather
455  * than the CIL itself.
456  *
457  * With dynamic reservations, we can effectively make up arbitrary limits for
458  * the checkpoint size so long as they don't violate any other size rules.
459  * Recovery imposes a rule that no transaction exceed half the log, so we are
460  * limited by that.  Furthermore, the log transaction reservation subsystem
461  * tries to keep 25% of the log free, so we need to keep below that limit or we
462  * risk running out of free log space to start any new transactions.
463  *
464  * In order to keep background CIL push efficient, we will set a lower
465  * threshold at which background pushing is attempted without blocking current
466  * transaction commits.  A separate, higher bound defines when CIL pushes are
467  * enforced to ensure we stay within our maximum checkpoint size bounds.
468  * threshold, yet give us plenty of space for aggregation on large logs.
469  */
470 #define XLOG_CIL_SPACE_LIMIT(log)	(log->l_logsize >> 3)
471 #define XLOG_CIL_HARD_SPACE_LIMIT(log)	(3 * (log->l_logsize >> 4))
472 
473 /*
474  * The reservation head lsn is not made up of a cycle number and block number.
475  * Instead, it uses a cycle number and byte number.  Logs don't expect to
476  * overflow 31 bits worth of byte offset, so using a byte number will mean
477  * that round off problems won't occur when releasing partial reservations.
478  */
479 typedef struct log {
480 	/* The following fields don't need locking */
481 	struct xfs_mount	*l_mp;	        /* mount point */
482 	struct xfs_ail		*l_ailp;	/* AIL log is working with */
483 	struct xfs_cil		*l_cilp;	/* CIL log is working with */
484 	struct xfs_buf		*l_xbuf;        /* extra buffer for log
485 						 * wrapping */
486 	struct xfs_buftarg	*l_targ;        /* buftarg of log */
487 	uint			l_flags;
488 	uint			l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
489 	struct list_head	*l_buf_cancel_table;
490 	int			l_iclog_hsize;  /* size of iclog header */
491 	int			l_iclog_heads;  /* # of iclog header sectors */
492 	uint			l_sectBBsize;   /* sector size in BBs (2^n) */
493 	int			l_iclog_size;	/* size of log in bytes */
494 	int			l_iclog_size_log; /* log power size of log */
495 	int			l_iclog_bufs;	/* number of iclog buffers */
496 	xfs_daddr_t		l_logBBstart;   /* start block of log */
497 	int			l_logsize;      /* size of log in bytes */
498 	int			l_logBBsize;    /* size of log in BB chunks */
499 
500 	/* The following block of fields are changed while holding icloglock */
501 	wait_queue_head_t	l_flush_wait ____cacheline_aligned_in_smp;
502 						/* waiting for iclog flush */
503 	int			l_covered_state;/* state of "covering disk
504 						 * log entries" */
505 	xlog_in_core_t		*l_iclog;       /* head log queue	*/
506 	spinlock_t		l_icloglock;    /* grab to change iclog state */
507 	int			l_curr_cycle;   /* Cycle number of log writes */
508 	int			l_prev_cycle;   /* Cycle number before last
509 						 * block increment */
510 	int			l_curr_block;   /* current logical log block */
511 	int			l_prev_block;   /* previous logical log block */
512 
513 	/*
514 	 * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
515 	 * read without needing to hold specific locks. To avoid operations
516 	 * contending with other hot objects, place each of them on a separate
517 	 * cacheline.
518 	 */
519 	/* lsn of last LR on disk */
520 	atomic64_t		l_last_sync_lsn ____cacheline_aligned_in_smp;
521 	/* lsn of 1st LR with unflushed * buffers */
522 	atomic64_t		l_tail_lsn ____cacheline_aligned_in_smp;
523 
524 	/*
525 	 * ticket grant locks, queues and accounting have their own cachlines
526 	 * as these are quite hot and can be operated on concurrently.
527 	 */
528 	spinlock_t		l_grant_reserve_lock ____cacheline_aligned_in_smp;
529 	struct list_head	l_reserveq;
530 	atomic64_t		l_grant_reserve_head;
531 
532 	spinlock_t		l_grant_write_lock ____cacheline_aligned_in_smp;
533 	struct list_head	l_writeq;
534 	atomic64_t		l_grant_write_head;
535 
536 	/* The following field are used for debugging; need to hold icloglock */
537 #ifdef DEBUG
538 	char			*l_iclog_bak[XLOG_MAX_ICLOGS];
539 #endif
540 
541 } xlog_t;
542 
543 #define XLOG_BUF_CANCEL_BUCKET(log, blkno) \
544 	((log)->l_buf_cancel_table + ((__uint64_t)blkno % XLOG_BC_TABLE_SIZE))
545 
546 #define XLOG_FORCED_SHUTDOWN(log)	((log)->l_flags & XLOG_IO_ERROR)
547 
548 /* common routines */
549 extern xfs_lsn_t xlog_assign_tail_lsn(struct xfs_mount *mp);
550 extern int	 xlog_recover(xlog_t *log);
551 extern int	 xlog_recover_finish(xlog_t *log);
552 extern void	 xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int);
553 
554 extern kmem_zone_t *xfs_log_ticket_zone;
555 struct xlog_ticket *xlog_ticket_alloc(struct log *log, int unit_bytes,
556 				int count, char client, uint xflags,
557 				int alloc_flags);
558 
559 
560 static inline void
561 xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes)
562 {
563 	*ptr += bytes;
564 	*len -= bytes;
565 	*off += bytes;
566 }
567 
568 void	xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
569 int	xlog_write(struct log *log, struct xfs_log_vec *log_vector,
570 				struct xlog_ticket *tic, xfs_lsn_t *start_lsn,
571 				xlog_in_core_t **commit_iclog, uint flags);
572 
573 /*
574  * When we crack an atomic LSN, we sample it first so that the value will not
575  * change while we are cracking it into the component values. This means we
576  * will always get consistent component values to work from. This should always
577  * be used to smaple and crack LSNs taht are stored and updated in atomic
578  * variables.
579  */
580 static inline void
581 xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
582 {
583 	xfs_lsn_t val = atomic64_read(lsn);
584 
585 	*cycle = CYCLE_LSN(val);
586 	*block = BLOCK_LSN(val);
587 }
588 
589 /*
590  * Calculate and assign a value to an atomic LSN variable from component pieces.
591  */
592 static inline void
593 xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
594 {
595 	atomic64_set(lsn, xlog_assign_lsn(cycle, block));
596 }
597 
598 /*
599  * When we crack the grant head, we sample it first so that the value will not
600  * change while we are cracking it into the component values. This means we
601  * will always get consistent component values to work from.
602  */
603 static inline void
604 xlog_crack_grant_head_val(int64_t val, int *cycle, int *space)
605 {
606 	*cycle = val >> 32;
607 	*space = val & 0xffffffff;
608 }
609 
610 static inline void
611 xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
612 {
613 	xlog_crack_grant_head_val(atomic64_read(head), cycle, space);
614 }
615 
616 static inline int64_t
617 xlog_assign_grant_head_val(int cycle, int space)
618 {
619 	return ((int64_t)cycle << 32) | space;
620 }
621 
622 static inline void
623 xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
624 {
625 	atomic64_set(head, xlog_assign_grant_head_val(cycle, space));
626 }
627 
628 /*
629  * Committed Item List interfaces
630  */
631 int	xlog_cil_init(struct log *log);
632 void	xlog_cil_init_post_recovery(struct log *log);
633 void	xlog_cil_destroy(struct log *log);
634 
635 /*
636  * CIL force routines
637  */
638 xfs_lsn_t xlog_cil_force_lsn(struct log *log, xfs_lsn_t sequence);
639 
640 static inline void
641 xlog_cil_force(struct log *log)
642 {
643 	xlog_cil_force_lsn(log, log->l_cilp->xc_current_sequence);
644 }
645 
646 /*
647  * Unmount record type is used as a pseudo transaction type for the ticket.
648  * It's value must be outside the range of XFS_TRANS_* values.
649  */
650 #define XLOG_UNMOUNT_REC_TYPE	(-1U)
651 
652 /*
653  * Wrapper function for waiting on a wait queue serialised against wakeups
654  * by a spinlock. This matches the semantics of all the wait queues used in the
655  * log code.
656  */
657 static inline void xlog_wait(wait_queue_head_t *wq, spinlock_t *lock)
658 {
659 	DECLARE_WAITQUEUE(wait, current);
660 
661 	add_wait_queue_exclusive(wq, &wait);
662 	__set_current_state(TASK_UNINTERRUPTIBLE);
663 	spin_unlock(lock);
664 	schedule();
665 	remove_wait_queue(wq, &wait);
666 }
667 #endif	/* __KERNEL__ */
668 
669 #endif	/* __XFS_LOG_PRIV_H__ */
670