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 
xlog_assign_lsn(uint cycle,uint block)56 static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
57 {
58 	return ((xfs_lsn_t)cycle << 32) | block;
59 }
60 
xlog_get_cycle(char * ptr)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  */
xlog_get_client_id(__be32 i)85 static 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 
149 typedef __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  */
236 typedef struct xlog_res {
237 	uint	r_len;	/* region length		:4 */
238 	uint	r_type;	/* region's transaction type	:4 */
239 } xlog_res_t;
240 
241 typedef 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 
265 typedef 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 
287 typedef 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 
304 typedef 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  */
314 typedef 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  */
349 typedef 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 log		*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  */
379 struct xfs_cil;
380 
381 struct 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  */
411 struct xfs_cil {
412 	struct log		*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 };
421 
422 /*
423  * The amount of log space we allow the CIL to aggregate is difficult to size.
424  * Whatever we choose, we have to make sure we can get a reservation for the
425  * log space effectively, that it is large enough to capture sufficient
426  * relogging to reduce log buffer IO significantly, but it is not too large for
427  * the log or induces too much latency when writing out through the iclogs. We
428  * track both space consumed and the number of vectors in the checkpoint
429  * context, so we need to decide which to use for limiting.
430  *
431  * Every log buffer we write out during a push needs a header reserved, which
432  * is at least one sector and more for v2 logs. Hence we need a reservation of
433  * at least 512 bytes per 32k of log space just for the LR headers. That means
434  * 16KB of reservation per megabyte of delayed logging space we will consume,
435  * plus various headers.  The number of headers will vary based on the num of
436  * io vectors, so limiting on a specific number of vectors is going to result
437  * in transactions of varying size. IOWs, it is more consistent to track and
438  * limit space consumed in the log rather than by the number of objects being
439  * logged in order to prevent checkpoint ticket overruns.
440  *
441  * Further, use of static reservations through the log grant mechanism is
442  * problematic. It introduces a lot of complexity (e.g. reserve grant vs write
443  * grant) and a significant deadlock potential because regranting write space
444  * can block on log pushes. Hence if we have to regrant log space during a log
445  * push, we can deadlock.
446  *
447  * However, we can avoid this by use of a dynamic "reservation stealing"
448  * technique during transaction commit whereby unused reservation space in the
449  * transaction ticket is transferred to the CIL ctx commit ticket to cover the
450  * space needed by the checkpoint transaction. This means that we never need to
451  * specifically reserve space for the CIL checkpoint transaction, nor do we
452  * need to regrant space once the checkpoint completes. This also means the
453  * checkpoint transaction ticket is specific to the checkpoint context, rather
454  * than the CIL itself.
455  *
456  * With dynamic reservations, we can effectively make up arbitrary limits for
457  * the checkpoint size so long as they don't violate any other size rules.
458  * Recovery imposes a rule that no transaction exceed half the log, so we are
459  * limited by that.  Furthermore, the log transaction reservation subsystem
460  * tries to keep 25% of the log free, so we need to keep below that limit or we
461  * risk running out of free log space to start any new transactions.
462  *
463  * In order to keep background CIL push efficient, we will set a lower
464  * threshold at which background pushing is attempted without blocking current
465  * transaction commits.  A separate, higher bound defines when CIL pushes are
466  * enforced to ensure we stay within our maximum checkpoint size bounds.
467  * threshold, yet give us plenty of space for aggregation on large logs.
468  */
469 #define XLOG_CIL_SPACE_LIMIT(log)	(log->l_logsize >> 3)
470 #define XLOG_CIL_HARD_SPACE_LIMIT(log)	(3 * (log->l_logsize >> 4))
471 
472 /*
473  * ticket grant locks, queues and accounting have their own cachlines
474  * as these are quite hot and can be operated on concurrently.
475  */
476 struct xlog_grant_head {
477 	spinlock_t		lock ____cacheline_aligned_in_smp;
478 	struct list_head	waiters;
479 	atomic64_t		grant;
480 };
481 
482 /*
483  * The reservation head lsn is not made up of a cycle number and block number.
484  * Instead, it uses a cycle number and byte number.  Logs don't expect to
485  * overflow 31 bits worth of byte offset, so using a byte number will mean
486  * that round off problems won't occur when releasing partial reservations.
487  */
488 typedef struct log {
489 	/* The following fields don't need locking */
490 	struct xfs_mount	*l_mp;	        /* mount point */
491 	struct xfs_ail		*l_ailp;	/* AIL log is working with */
492 	struct xfs_cil		*l_cilp;	/* CIL log is working with */
493 	struct xfs_buf		*l_xbuf;        /* extra buffer for log
494 						 * wrapping */
495 	struct xfs_buftarg	*l_targ;        /* buftarg of log */
496 	uint			l_flags;
497 	uint			l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
498 	struct list_head	*l_buf_cancel_table;
499 	int			l_iclog_hsize;  /* size of iclog header */
500 	int			l_iclog_heads;  /* # of iclog header sectors */
501 	uint			l_sectBBsize;   /* sector size in BBs (2^n) */
502 	int			l_iclog_size;	/* size of log in bytes */
503 	int			l_iclog_size_log; /* log power size of log */
504 	int			l_iclog_bufs;	/* number of iclog buffers */
505 	xfs_daddr_t		l_logBBstart;   /* start block of log */
506 	int			l_logsize;      /* size of log in bytes */
507 	int			l_logBBsize;    /* size of log in BB chunks */
508 
509 	/* The following block of fields are changed while holding icloglock */
510 	wait_queue_head_t	l_flush_wait ____cacheline_aligned_in_smp;
511 						/* waiting for iclog flush */
512 	int			l_covered_state;/* state of "covering disk
513 						 * log entries" */
514 	xlog_in_core_t		*l_iclog;       /* head log queue	*/
515 	spinlock_t		l_icloglock;    /* grab to change iclog state */
516 	int			l_curr_cycle;   /* Cycle number of log writes */
517 	int			l_prev_cycle;   /* Cycle number before last
518 						 * block increment */
519 	int			l_curr_block;   /* current logical log block */
520 	int			l_prev_block;   /* previous logical log block */
521 
522 	/*
523 	 * l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
524 	 * read without needing to hold specific locks. To avoid operations
525 	 * contending with other hot objects, place each of them on a separate
526 	 * cacheline.
527 	 */
528 	/* lsn of last LR on disk */
529 	atomic64_t		l_last_sync_lsn ____cacheline_aligned_in_smp;
530 	/* lsn of 1st LR with unflushed * buffers */
531 	atomic64_t		l_tail_lsn ____cacheline_aligned_in_smp;
532 
533 	struct xlog_grant_head	l_reserve_head;
534 	struct xlog_grant_head	l_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 int	 xlog_recover(xlog_t *log);
550 extern int	 xlog_recover_finish(xlog_t *log);
551 extern void	 xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int);
552 
553 extern kmem_zone_t *xfs_log_ticket_zone;
554 struct xlog_ticket *xlog_ticket_alloc(struct log *log, int unit_bytes,
555 				int count, char client, bool permanent,
556 				int alloc_flags);
557 
558 
559 static inline void
xlog_write_adv_cnt(void ** ptr,int * len,int * off,size_t bytes)560 xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes)
561 {
562 	*ptr += bytes;
563 	*len -= bytes;
564 	*off += bytes;
565 }
566 
567 void	xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
568 int	xlog_write(struct log *log, struct xfs_log_vec *log_vector,
569 				struct xlog_ticket *tic, xfs_lsn_t *start_lsn,
570 				xlog_in_core_t **commit_iclog, uint flags);
571 
572 /*
573  * When we crack an atomic LSN, we sample it first so that the value will not
574  * change while we are cracking it into the component values. This means we
575  * will always get consistent component values to work from. This should always
576  * be used to sample and crack LSNs that are stored and updated in atomic
577  * variables.
578  */
579 static inline void
xlog_crack_atomic_lsn(atomic64_t * lsn,uint * cycle,uint * block)580 xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
581 {
582 	xfs_lsn_t val = atomic64_read(lsn);
583 
584 	*cycle = CYCLE_LSN(val);
585 	*block = BLOCK_LSN(val);
586 }
587 
588 /*
589  * Calculate and assign a value to an atomic LSN variable from component pieces.
590  */
591 static inline void
xlog_assign_atomic_lsn(atomic64_t * lsn,uint cycle,uint block)592 xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
593 {
594 	atomic64_set(lsn, xlog_assign_lsn(cycle, block));
595 }
596 
597 /*
598  * When we crack the grant head, we sample it first so that the value will not
599  * change while we are cracking it into the component values. This means we
600  * will always get consistent component values to work from.
601  */
602 static inline void
xlog_crack_grant_head_val(int64_t val,int * cycle,int * space)603 xlog_crack_grant_head_val(int64_t val, int *cycle, int *space)
604 {
605 	*cycle = val >> 32;
606 	*space = val & 0xffffffff;
607 }
608 
609 static inline void
xlog_crack_grant_head(atomic64_t * head,int * cycle,int * space)610 xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
611 {
612 	xlog_crack_grant_head_val(atomic64_read(head), cycle, space);
613 }
614 
615 static inline int64_t
xlog_assign_grant_head_val(int cycle,int space)616 xlog_assign_grant_head_val(int cycle, int space)
617 {
618 	return ((int64_t)cycle << 32) | space;
619 }
620 
621 static inline void
xlog_assign_grant_head(atomic64_t * head,int cycle,int space)622 xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
623 {
624 	atomic64_set(head, xlog_assign_grant_head_val(cycle, space));
625 }
626 
627 /*
628  * Committed Item List interfaces
629  */
630 int	xlog_cil_init(struct log *log);
631 void	xlog_cil_init_post_recovery(struct log *log);
632 void	xlog_cil_destroy(struct log *log);
633 
634 /*
635  * CIL force routines
636  */
637 xfs_lsn_t xlog_cil_force_lsn(struct log *log, xfs_lsn_t sequence);
638 
639 static inline void
xlog_cil_force(struct log * log)640 xlog_cil_force(struct log *log)
641 {
642 	xlog_cil_force_lsn(log, log->l_cilp->xc_current_sequence);
643 }
644 
645 /*
646  * Unmount record type is used as a pseudo transaction type for the ticket.
647  * It's value must be outside the range of XFS_TRANS_* values.
648  */
649 #define XLOG_UNMOUNT_REC_TYPE	(-1U)
650 
651 /*
652  * Wrapper function for waiting on a wait queue serialised against wakeups
653  * by a spinlock. This matches the semantics of all the wait queues used in the
654  * log code.
655  */
xlog_wait(wait_queue_head_t * wq,spinlock_t * lock)656 static inline void xlog_wait(wait_queue_head_t *wq, spinlock_t *lock)
657 {
658 	DECLARE_WAITQUEUE(wait, current);
659 
660 	add_wait_queue_exclusive(wq, &wait);
661 	__set_current_state(TASK_UNINTERRUPTIBLE);
662 	spin_unlock(lock);
663 	schedule();
664 	remove_wait_queue(wq, &wait);
665 }
666 #endif	/* __KERNEL__ */
667 
668 #endif	/* __XFS_LOG_PRIV_H__ */
669