Merge tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device...
[linux-2.6-microblaze.git] / fs / xfs / xfs_log.c
1 /*
2  * Copyright (c) 2000-2005 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 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_shared.h"
21 #include "xfs_format.h"
22 #include "xfs_log_format.h"
23 #include "xfs_trans_resv.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_mount.h"
27 #include "xfs_error.h"
28 #include "xfs_trans.h"
29 #include "xfs_trans_priv.h"
30 #include "xfs_log.h"
31 #include "xfs_log_priv.h"
32 #include "xfs_log_recover.h"
33 #include "xfs_inode.h"
34 #include "xfs_trace.h"
35 #include "xfs_fsops.h"
36 #include "xfs_cksum.h"
37 #include "xfs_sysfs.h"
38
39 kmem_zone_t     *xfs_log_ticket_zone;
40
41 /* Local miscellaneous function prototypes */
42 STATIC int
43 xlog_commit_record(
44         struct xlog             *log,
45         struct xlog_ticket      *ticket,
46         struct xlog_in_core     **iclog,
47         xfs_lsn_t               *commitlsnp);
48
49 STATIC struct xlog *
50 xlog_alloc_log(
51         struct xfs_mount        *mp,
52         struct xfs_buftarg      *log_target,
53         xfs_daddr_t             blk_offset,
54         int                     num_bblks);
55 STATIC int
56 xlog_space_left(
57         struct xlog             *log,
58         atomic64_t              *head);
59 STATIC int
60 xlog_sync(
61         struct xlog             *log,
62         struct xlog_in_core     *iclog);
63 STATIC void
64 xlog_dealloc_log(
65         struct xlog             *log);
66
67 /* local state machine functions */
68 STATIC void xlog_state_done_syncing(xlog_in_core_t *iclog, int);
69 STATIC void
70 xlog_state_do_callback(
71         struct xlog             *log,
72         int                     aborted,
73         struct xlog_in_core     *iclog);
74 STATIC int
75 xlog_state_get_iclog_space(
76         struct xlog             *log,
77         int                     len,
78         struct xlog_in_core     **iclog,
79         struct xlog_ticket      *ticket,
80         int                     *continued_write,
81         int                     *logoffsetp);
82 STATIC int
83 xlog_state_release_iclog(
84         struct xlog             *log,
85         struct xlog_in_core     *iclog);
86 STATIC void
87 xlog_state_switch_iclogs(
88         struct xlog             *log,
89         struct xlog_in_core     *iclog,
90         int                     eventual_size);
91 STATIC void
92 xlog_state_want_sync(
93         struct xlog             *log,
94         struct xlog_in_core     *iclog);
95
96 STATIC void
97 xlog_grant_push_ail(
98         struct xlog             *log,
99         int                     need_bytes);
100 STATIC void
101 xlog_regrant_reserve_log_space(
102         struct xlog             *log,
103         struct xlog_ticket      *ticket);
104 STATIC void
105 xlog_ungrant_log_space(
106         struct xlog             *log,
107         struct xlog_ticket      *ticket);
108
109 #if defined(DEBUG)
110 STATIC void
111 xlog_verify_dest_ptr(
112         struct xlog             *log,
113         char                    *ptr);
114 STATIC void
115 xlog_verify_grant_tail(
116         struct xlog *log);
117 STATIC void
118 xlog_verify_iclog(
119         struct xlog             *log,
120         struct xlog_in_core     *iclog,
121         int                     count,
122         bool                    syncing);
123 STATIC void
124 xlog_verify_tail_lsn(
125         struct xlog             *log,
126         struct xlog_in_core     *iclog,
127         xfs_lsn_t               tail_lsn);
128 #else
129 #define xlog_verify_dest_ptr(a,b)
130 #define xlog_verify_grant_tail(a)
131 #define xlog_verify_iclog(a,b,c,d)
132 #define xlog_verify_tail_lsn(a,b,c)
133 #endif
134
135 STATIC int
136 xlog_iclogs_empty(
137         struct xlog             *log);
138
139 static void
140 xlog_grant_sub_space(
141         struct xlog             *log,
142         atomic64_t              *head,
143         int                     bytes)
144 {
145         int64_t head_val = atomic64_read(head);
146         int64_t new, old;
147
148         do {
149                 int     cycle, space;
150
151                 xlog_crack_grant_head_val(head_val, &cycle, &space);
152
153                 space -= bytes;
154                 if (space < 0) {
155                         space += log->l_logsize;
156                         cycle--;
157                 }
158
159                 old = head_val;
160                 new = xlog_assign_grant_head_val(cycle, space);
161                 head_val = atomic64_cmpxchg(head, old, new);
162         } while (head_val != old);
163 }
164
165 static void
166 xlog_grant_add_space(
167         struct xlog             *log,
168         atomic64_t              *head,
169         int                     bytes)
170 {
171         int64_t head_val = atomic64_read(head);
172         int64_t new, old;
173
174         do {
175                 int             tmp;
176                 int             cycle, space;
177
178                 xlog_crack_grant_head_val(head_val, &cycle, &space);
179
180                 tmp = log->l_logsize - space;
181                 if (tmp > bytes)
182                         space += bytes;
183                 else {
184                         space = bytes - tmp;
185                         cycle++;
186                 }
187
188                 old = head_val;
189                 new = xlog_assign_grant_head_val(cycle, space);
190                 head_val = atomic64_cmpxchg(head, old, new);
191         } while (head_val != old);
192 }
193
194 STATIC void
195 xlog_grant_head_init(
196         struct xlog_grant_head  *head)
197 {
198         xlog_assign_grant_head(&head->grant, 1, 0);
199         INIT_LIST_HEAD(&head->waiters);
200         spin_lock_init(&head->lock);
201 }
202
203 STATIC void
204 xlog_grant_head_wake_all(
205         struct xlog_grant_head  *head)
206 {
207         struct xlog_ticket      *tic;
208
209         spin_lock(&head->lock);
210         list_for_each_entry(tic, &head->waiters, t_queue)
211                 wake_up_process(tic->t_task);
212         spin_unlock(&head->lock);
213 }
214
215 static inline int
216 xlog_ticket_reservation(
217         struct xlog             *log,
218         struct xlog_grant_head  *head,
219         struct xlog_ticket      *tic)
220 {
221         if (head == &log->l_write_head) {
222                 ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
223                 return tic->t_unit_res;
224         } else {
225                 if (tic->t_flags & XLOG_TIC_PERM_RESERV)
226                         return tic->t_unit_res * tic->t_cnt;
227                 else
228                         return tic->t_unit_res;
229         }
230 }
231
232 STATIC bool
233 xlog_grant_head_wake(
234         struct xlog             *log,
235         struct xlog_grant_head  *head,
236         int                     *free_bytes)
237 {
238         struct xlog_ticket      *tic;
239         int                     need_bytes;
240
241         list_for_each_entry(tic, &head->waiters, t_queue) {
242                 need_bytes = xlog_ticket_reservation(log, head, tic);
243                 if (*free_bytes < need_bytes)
244                         return false;
245
246                 *free_bytes -= need_bytes;
247                 trace_xfs_log_grant_wake_up(log, tic);
248                 wake_up_process(tic->t_task);
249         }
250
251         return true;
252 }
253
254 STATIC int
255 xlog_grant_head_wait(
256         struct xlog             *log,
257         struct xlog_grant_head  *head,
258         struct xlog_ticket      *tic,
259         int                     need_bytes) __releases(&head->lock)
260                                             __acquires(&head->lock)
261 {
262         list_add_tail(&tic->t_queue, &head->waiters);
263
264         do {
265                 if (XLOG_FORCED_SHUTDOWN(log))
266                         goto shutdown;
267                 xlog_grant_push_ail(log, need_bytes);
268
269                 __set_current_state(TASK_UNINTERRUPTIBLE);
270                 spin_unlock(&head->lock);
271
272                 XFS_STATS_INC(xs_sleep_logspace);
273
274                 trace_xfs_log_grant_sleep(log, tic);
275                 schedule();
276                 trace_xfs_log_grant_wake(log, tic);
277
278                 spin_lock(&head->lock);
279                 if (XLOG_FORCED_SHUTDOWN(log))
280                         goto shutdown;
281         } while (xlog_space_left(log, &head->grant) < need_bytes);
282
283         list_del_init(&tic->t_queue);
284         return 0;
285 shutdown:
286         list_del_init(&tic->t_queue);
287         return -EIO;
288 }
289
290 /*
291  * Atomically get the log space required for a log ticket.
292  *
293  * Once a ticket gets put onto head->waiters, it will only return after the
294  * needed reservation is satisfied.
295  *
296  * This function is structured so that it has a lock free fast path. This is
297  * necessary because every new transaction reservation will come through this
298  * path. Hence any lock will be globally hot if we take it unconditionally on
299  * every pass.
300  *
301  * As tickets are only ever moved on and off head->waiters under head->lock, we
302  * only need to take that lock if we are going to add the ticket to the queue
303  * and sleep. We can avoid taking the lock if the ticket was never added to
304  * head->waiters because the t_queue list head will be empty and we hold the
305  * only reference to it so it can safely be checked unlocked.
306  */
307 STATIC int
308 xlog_grant_head_check(
309         struct xlog             *log,
310         struct xlog_grant_head  *head,
311         struct xlog_ticket      *tic,
312         int                     *need_bytes)
313 {
314         int                     free_bytes;
315         int                     error = 0;
316
317         ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
318
319         /*
320          * If there are other waiters on the queue then give them a chance at
321          * logspace before us.  Wake up the first waiters, if we do not wake
322          * up all the waiters then go to sleep waiting for more free space,
323          * otherwise try to get some space for this transaction.
324          */
325         *need_bytes = xlog_ticket_reservation(log, head, tic);
326         free_bytes = xlog_space_left(log, &head->grant);
327         if (!list_empty_careful(&head->waiters)) {
328                 spin_lock(&head->lock);
329                 if (!xlog_grant_head_wake(log, head, &free_bytes) ||
330                     free_bytes < *need_bytes) {
331                         error = xlog_grant_head_wait(log, head, tic,
332                                                      *need_bytes);
333                 }
334                 spin_unlock(&head->lock);
335         } else if (free_bytes < *need_bytes) {
336                 spin_lock(&head->lock);
337                 error = xlog_grant_head_wait(log, head, tic, *need_bytes);
338                 spin_unlock(&head->lock);
339         }
340
341         return error;
342 }
343
344 static void
345 xlog_tic_reset_res(xlog_ticket_t *tic)
346 {
347         tic->t_res_num = 0;
348         tic->t_res_arr_sum = 0;
349         tic->t_res_num_ophdrs = 0;
350 }
351
352 static void
353 xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
354 {
355         if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
356                 /* add to overflow and start again */
357                 tic->t_res_o_flow += tic->t_res_arr_sum;
358                 tic->t_res_num = 0;
359                 tic->t_res_arr_sum = 0;
360         }
361
362         tic->t_res_arr[tic->t_res_num].r_len = len;
363         tic->t_res_arr[tic->t_res_num].r_type = type;
364         tic->t_res_arr_sum += len;
365         tic->t_res_num++;
366 }
367
368 /*
369  * Replenish the byte reservation required by moving the grant write head.
370  */
371 int
372 xfs_log_regrant(
373         struct xfs_mount        *mp,
374         struct xlog_ticket      *tic)
375 {
376         struct xlog             *log = mp->m_log;
377         int                     need_bytes;
378         int                     error = 0;
379
380         if (XLOG_FORCED_SHUTDOWN(log))
381                 return -EIO;
382
383         XFS_STATS_INC(xs_try_logspace);
384
385         /*
386          * This is a new transaction on the ticket, so we need to change the
387          * transaction ID so that the next transaction has a different TID in
388          * the log. Just add one to the existing tid so that we can see chains
389          * of rolling transactions in the log easily.
390          */
391         tic->t_tid++;
392
393         xlog_grant_push_ail(log, tic->t_unit_res);
394
395         tic->t_curr_res = tic->t_unit_res;
396         xlog_tic_reset_res(tic);
397
398         if (tic->t_cnt > 0)
399                 return 0;
400
401         trace_xfs_log_regrant(log, tic);
402
403         error = xlog_grant_head_check(log, &log->l_write_head, tic,
404                                       &need_bytes);
405         if (error)
406                 goto out_error;
407
408         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
409         trace_xfs_log_regrant_exit(log, tic);
410         xlog_verify_grant_tail(log);
411         return 0;
412
413 out_error:
414         /*
415          * If we are failing, make sure the ticket doesn't have any current
416          * reservations.  We don't want to add this back when the ticket/
417          * transaction gets cancelled.
418          */
419         tic->t_curr_res = 0;
420         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
421         return error;
422 }
423
424 /*
425  * Reserve log space and return a ticket corresponding the reservation.
426  *
427  * Each reservation is going to reserve extra space for a log record header.
428  * When writes happen to the on-disk log, we don't subtract the length of the
429  * log record header from any reservation.  By wasting space in each
430  * reservation, we prevent over allocation problems.
431  */
432 int
433 xfs_log_reserve(
434         struct xfs_mount        *mp,
435         int                     unit_bytes,
436         int                     cnt,
437         struct xlog_ticket      **ticp,
438         __uint8_t               client,
439         bool                    permanent,
440         uint                    t_type)
441 {
442         struct xlog             *log = mp->m_log;
443         struct xlog_ticket      *tic;
444         int                     need_bytes;
445         int                     error = 0;
446
447         ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
448
449         if (XLOG_FORCED_SHUTDOWN(log))
450                 return -EIO;
451
452         XFS_STATS_INC(xs_try_logspace);
453
454         ASSERT(*ticp == NULL);
455         tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent,
456                                 KM_SLEEP | KM_MAYFAIL);
457         if (!tic)
458                 return -ENOMEM;
459
460         tic->t_trans_type = t_type;
461         *ticp = tic;
462
463         xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
464                                             : tic->t_unit_res);
465
466         trace_xfs_log_reserve(log, tic);
467
468         error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
469                                       &need_bytes);
470         if (error)
471                 goto out_error;
472
473         xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
474         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
475         trace_xfs_log_reserve_exit(log, tic);
476         xlog_verify_grant_tail(log);
477         return 0;
478
479 out_error:
480         /*
481          * If we are failing, make sure the ticket doesn't have any current
482          * reservations.  We don't want to add this back when the ticket/
483          * transaction gets cancelled.
484          */
485         tic->t_curr_res = 0;
486         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
487         return error;
488 }
489
490
491 /*
492  * NOTES:
493  *
494  *      1. currblock field gets updated at startup and after in-core logs
495  *              marked as with WANT_SYNC.
496  */
497
498 /*
499  * This routine is called when a user of a log manager ticket is done with
500  * the reservation.  If the ticket was ever used, then a commit record for
501  * the associated transaction is written out as a log operation header with
502  * no data.  The flag XLOG_TIC_INITED is set when the first write occurs with
503  * a given ticket.  If the ticket was one with a permanent reservation, then
504  * a few operations are done differently.  Permanent reservation tickets by
505  * default don't release the reservation.  They just commit the current
506  * transaction with the belief that the reservation is still needed.  A flag
507  * must be passed in before permanent reservations are actually released.
508  * When these type of tickets are not released, they need to be set into
509  * the inited state again.  By doing this, a start record will be written
510  * out when the next write occurs.
511  */
512 xfs_lsn_t
513 xfs_log_done(
514         struct xfs_mount        *mp,
515         struct xlog_ticket      *ticket,
516         struct xlog_in_core     **iclog,
517         uint                    flags)
518 {
519         struct xlog             *log = mp->m_log;
520         xfs_lsn_t               lsn = 0;
521
522         if (XLOG_FORCED_SHUTDOWN(log) ||
523             /*
524              * If nothing was ever written, don't write out commit record.
525              * If we get an error, just continue and give back the log ticket.
526              */
527             (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
528              (xlog_commit_record(log, ticket, iclog, &lsn)))) {
529                 lsn = (xfs_lsn_t) -1;
530                 if (ticket->t_flags & XLOG_TIC_PERM_RESERV) {
531                         flags |= XFS_LOG_REL_PERM_RESERV;
532                 }
533         }
534
535
536         if ((ticket->t_flags & XLOG_TIC_PERM_RESERV) == 0 ||
537             (flags & XFS_LOG_REL_PERM_RESERV)) {
538                 trace_xfs_log_done_nonperm(log, ticket);
539
540                 /*
541                  * Release ticket if not permanent reservation or a specific
542                  * request has been made to release a permanent reservation.
543                  */
544                 xlog_ungrant_log_space(log, ticket);
545                 xfs_log_ticket_put(ticket);
546         } else {
547                 trace_xfs_log_done_perm(log, ticket);
548
549                 xlog_regrant_reserve_log_space(log, ticket);
550                 /* If this ticket was a permanent reservation and we aren't
551                  * trying to release it, reset the inited flags; so next time
552                  * we write, a start record will be written out.
553                  */
554                 ticket->t_flags |= XLOG_TIC_INITED;
555         }
556
557         return lsn;
558 }
559
560 /*
561  * Attaches a new iclog I/O completion callback routine during
562  * transaction commit.  If the log is in error state, a non-zero
563  * return code is handed back and the caller is responsible for
564  * executing the callback at an appropriate time.
565  */
566 int
567 xfs_log_notify(
568         struct xfs_mount        *mp,
569         struct xlog_in_core     *iclog,
570         xfs_log_callback_t      *cb)
571 {
572         int     abortflg;
573
574         spin_lock(&iclog->ic_callback_lock);
575         abortflg = (iclog->ic_state & XLOG_STATE_IOERROR);
576         if (!abortflg) {
577                 ASSERT_ALWAYS((iclog->ic_state == XLOG_STATE_ACTIVE) ||
578                               (iclog->ic_state == XLOG_STATE_WANT_SYNC));
579                 cb->cb_next = NULL;
580                 *(iclog->ic_callback_tail) = cb;
581                 iclog->ic_callback_tail = &(cb->cb_next);
582         }
583         spin_unlock(&iclog->ic_callback_lock);
584         return abortflg;
585 }
586
587 int
588 xfs_log_release_iclog(
589         struct xfs_mount        *mp,
590         struct xlog_in_core     *iclog)
591 {
592         if (xlog_state_release_iclog(mp->m_log, iclog)) {
593                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
594                 return -EIO;
595         }
596
597         return 0;
598 }
599
600 /*
601  * Mount a log filesystem
602  *
603  * mp           - ubiquitous xfs mount point structure
604  * log_target   - buftarg of on-disk log device
605  * blk_offset   - Start block # where block size is 512 bytes (BBSIZE)
606  * num_bblocks  - Number of BBSIZE blocks in on-disk log
607  *
608  * Return error or zero.
609  */
610 int
611 xfs_log_mount(
612         xfs_mount_t     *mp,
613         xfs_buftarg_t   *log_target,
614         xfs_daddr_t     blk_offset,
615         int             num_bblks)
616 {
617         int             error = 0;
618         int             min_logfsbs;
619
620         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
621                 xfs_notice(mp, "Mounting V%d Filesystem",
622                            XFS_SB_VERSION_NUM(&mp->m_sb));
623         } else {
624                 xfs_notice(mp,
625 "Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.",
626                            XFS_SB_VERSION_NUM(&mp->m_sb));
627                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
628         }
629
630         mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
631         if (IS_ERR(mp->m_log)) {
632                 error = PTR_ERR(mp->m_log);
633                 goto out;
634         }
635
636         /*
637          * Validate the given log space and drop a critical message via syslog
638          * if the log size is too small that would lead to some unexpected
639          * situations in transaction log space reservation stage.
640          *
641          * Note: we can't just reject the mount if the validation fails.  This
642          * would mean that people would have to downgrade their kernel just to
643          * remedy the situation as there is no way to grow the log (short of
644          * black magic surgery with xfs_db).
645          *
646          * We can, however, reject mounts for CRC format filesystems, as the
647          * mkfs binary being used to make the filesystem should never create a
648          * filesystem with a log that is too small.
649          */
650         min_logfsbs = xfs_log_calc_minimum_size(mp);
651
652         if (mp->m_sb.sb_logblocks < min_logfsbs) {
653                 xfs_warn(mp,
654                 "Log size %d blocks too small, minimum size is %d blocks",
655                          mp->m_sb.sb_logblocks, min_logfsbs);
656                 error = -EINVAL;
657         } else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) {
658                 xfs_warn(mp,
659                 "Log size %d blocks too large, maximum size is %lld blocks",
660                          mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS);
661                 error = -EINVAL;
662         } else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) {
663                 xfs_warn(mp,
664                 "log size %lld bytes too large, maximum size is %lld bytes",
665                          XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
666                          XFS_MAX_LOG_BYTES);
667                 error = -EINVAL;
668         }
669         if (error) {
670                 if (xfs_sb_version_hascrc(&mp->m_sb)) {
671                         xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
672                         ASSERT(0);
673                         goto out_free_log;
674                 }
675                 xfs_crit(mp,
676 "Log size out of supported range. Continuing onwards, but if log hangs are\n"
677 "experienced then please report this message in the bug report.");
678         }
679
680         /*
681          * Initialize the AIL now we have a log.
682          */
683         error = xfs_trans_ail_init(mp);
684         if (error) {
685                 xfs_warn(mp, "AIL initialisation failed: error %d", error);
686                 goto out_free_log;
687         }
688         mp->m_log->l_ailp = mp->m_ail;
689
690         /*
691          * skip log recovery on a norecovery mount.  pretend it all
692          * just worked.
693          */
694         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
695                 int     readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
696
697                 if (readonly)
698                         mp->m_flags &= ~XFS_MOUNT_RDONLY;
699
700                 error = xlog_recover(mp->m_log);
701
702                 if (readonly)
703                         mp->m_flags |= XFS_MOUNT_RDONLY;
704                 if (error) {
705                         xfs_warn(mp, "log mount/recovery failed: error %d",
706                                 error);
707                         goto out_destroy_ail;
708                 }
709         }
710
711         error = xfs_sysfs_init(&mp->m_log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
712                                "log");
713         if (error)
714                 goto out_destroy_ail;
715
716         /* Normal transactions can now occur */
717         mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
718
719         /*
720          * Now the log has been fully initialised and we know were our
721          * space grant counters are, we can initialise the permanent ticket
722          * needed for delayed logging to work.
723          */
724         xlog_cil_init_post_recovery(mp->m_log);
725
726         return 0;
727
728 out_destroy_ail:
729         xfs_trans_ail_destroy(mp);
730 out_free_log:
731         xlog_dealloc_log(mp->m_log);
732 out:
733         return error;
734 }
735
736 /*
737  * Finish the recovery of the file system.  This is separate from the
738  * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
739  * in the root and real-time bitmap inodes between calling xfs_log_mount() and
740  * here.
741  *
742  * If we finish recovery successfully, start the background log work. If we are
743  * not doing recovery, then we have a RO filesystem and we don't need to start
744  * it.
745  */
746 int
747 xfs_log_mount_finish(xfs_mount_t *mp)
748 {
749         int     error = 0;
750
751         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
752                 error = xlog_recover_finish(mp->m_log);
753                 if (!error)
754                         xfs_log_work_queue(mp);
755         } else {
756                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
757         }
758
759
760         return error;
761 }
762
763 /*
764  * Final log writes as part of unmount.
765  *
766  * Mark the filesystem clean as unmount happens.  Note that during relocation
767  * this routine needs to be executed as part of source-bag while the
768  * deallocation must not be done until source-end.
769  */
770
771 /*
772  * Unmount record used to have a string "Unmount filesystem--" in the
773  * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
774  * We just write the magic number now since that particular field isn't
775  * currently architecture converted and "Unmount" is a bit foo.
776  * As far as I know, there weren't any dependencies on the old behaviour.
777  */
778
779 int
780 xfs_log_unmount_write(xfs_mount_t *mp)
781 {
782         struct xlog      *log = mp->m_log;
783         xlog_in_core_t   *iclog;
784 #ifdef DEBUG
785         xlog_in_core_t   *first_iclog;
786 #endif
787         xlog_ticket_t   *tic = NULL;
788         xfs_lsn_t        lsn;
789         int              error;
790
791         /*
792          * Don't write out unmount record on read-only mounts.
793          * Or, if we are doing a forced umount (typically because of IO errors).
794          */
795         if (mp->m_flags & XFS_MOUNT_RDONLY)
796                 return 0;
797
798         error = _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
799         ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
800
801 #ifdef DEBUG
802         first_iclog = iclog = log->l_iclog;
803         do {
804                 if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
805                         ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
806                         ASSERT(iclog->ic_offset == 0);
807                 }
808                 iclog = iclog->ic_next;
809         } while (iclog != first_iclog);
810 #endif
811         if (! (XLOG_FORCED_SHUTDOWN(log))) {
812                 error = xfs_log_reserve(mp, 600, 1, &tic,
813                                         XFS_LOG, 0, XLOG_UNMOUNT_REC_TYPE);
814                 if (!error) {
815                         /* the data section must be 32 bit size aligned */
816                         struct {
817                             __uint16_t magic;
818                             __uint16_t pad1;
819                             __uint32_t pad2; /* may as well make it 64 bits */
820                         } magic = {
821                                 .magic = XLOG_UNMOUNT_TYPE,
822                         };
823                         struct xfs_log_iovec reg = {
824                                 .i_addr = &magic,
825                                 .i_len = sizeof(magic),
826                                 .i_type = XLOG_REG_TYPE_UNMOUNT,
827                         };
828                         struct xfs_log_vec vec = {
829                                 .lv_niovecs = 1,
830                                 .lv_iovecp = &reg,
831                         };
832
833                         /* remove inited flag, and account for space used */
834                         tic->t_flags = 0;
835                         tic->t_curr_res -= sizeof(magic);
836                         error = xlog_write(log, &vec, tic, &lsn,
837                                            NULL, XLOG_UNMOUNT_TRANS);
838                         /*
839                          * At this point, we're umounting anyway,
840                          * so there's no point in transitioning log state
841                          * to IOERROR. Just continue...
842                          */
843                 }
844
845                 if (error)
846                         xfs_alert(mp, "%s: unmount record failed", __func__);
847
848
849                 spin_lock(&log->l_icloglock);
850                 iclog = log->l_iclog;
851                 atomic_inc(&iclog->ic_refcnt);
852                 xlog_state_want_sync(log, iclog);
853                 spin_unlock(&log->l_icloglock);
854                 error = xlog_state_release_iclog(log, iclog);
855
856                 spin_lock(&log->l_icloglock);
857                 if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
858                       iclog->ic_state == XLOG_STATE_DIRTY)) {
859                         if (!XLOG_FORCED_SHUTDOWN(log)) {
860                                 xlog_wait(&iclog->ic_force_wait,
861                                                         &log->l_icloglock);
862                         } else {
863                                 spin_unlock(&log->l_icloglock);
864                         }
865                 } else {
866                         spin_unlock(&log->l_icloglock);
867                 }
868                 if (tic) {
869                         trace_xfs_log_umount_write(log, tic);
870                         xlog_ungrant_log_space(log, tic);
871                         xfs_log_ticket_put(tic);
872                 }
873         } else {
874                 /*
875                  * We're already in forced_shutdown mode, couldn't
876                  * even attempt to write out the unmount transaction.
877                  *
878                  * Go through the motions of sync'ing and releasing
879                  * the iclog, even though no I/O will actually happen,
880                  * we need to wait for other log I/Os that may already
881                  * be in progress.  Do this as a separate section of
882                  * code so we'll know if we ever get stuck here that
883                  * we're in this odd situation of trying to unmount
884                  * a file system that went into forced_shutdown as
885                  * the result of an unmount..
886                  */
887                 spin_lock(&log->l_icloglock);
888                 iclog = log->l_iclog;
889                 atomic_inc(&iclog->ic_refcnt);
890
891                 xlog_state_want_sync(log, iclog);
892                 spin_unlock(&log->l_icloglock);
893                 error =  xlog_state_release_iclog(log, iclog);
894
895                 spin_lock(&log->l_icloglock);
896
897                 if ( ! (   iclog->ic_state == XLOG_STATE_ACTIVE
898                         || iclog->ic_state == XLOG_STATE_DIRTY
899                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
900
901                                 xlog_wait(&iclog->ic_force_wait,
902                                                         &log->l_icloglock);
903                 } else {
904                         spin_unlock(&log->l_icloglock);
905                 }
906         }
907
908         return error;
909 }       /* xfs_log_unmount_write */
910
911 /*
912  * Empty the log for unmount/freeze.
913  *
914  * To do this, we first need to shut down the background log work so it is not
915  * trying to cover the log as we clean up. We then need to unpin all objects in
916  * the log so we can then flush them out. Once they have completed their IO and
917  * run the callbacks removing themselves from the AIL, we can write the unmount
918  * record.
919  */
920 void
921 xfs_log_quiesce(
922         struct xfs_mount        *mp)
923 {
924         cancel_delayed_work_sync(&mp->m_log->l_work);
925         xfs_log_force(mp, XFS_LOG_SYNC);
926
927         /*
928          * The superblock buffer is uncached and while xfs_ail_push_all_sync()
929          * will push it, xfs_wait_buftarg() will not wait for it. Further,
930          * xfs_buf_iowait() cannot be used because it was pushed with the
931          * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
932          * the IO to complete.
933          */
934         xfs_ail_push_all_sync(mp->m_ail);
935         xfs_wait_buftarg(mp->m_ddev_targp);
936         xfs_buf_lock(mp->m_sb_bp);
937         xfs_buf_unlock(mp->m_sb_bp);
938
939         xfs_log_unmount_write(mp);
940 }
941
942 /*
943  * Shut down and release the AIL and Log.
944  *
945  * During unmount, we need to ensure we flush all the dirty metadata objects
946  * from the AIL so that the log is empty before we write the unmount record to
947  * the log. Once this is done, we can tear down the AIL and the log.
948  */
949 void
950 xfs_log_unmount(
951         struct xfs_mount        *mp)
952 {
953         xfs_log_quiesce(mp);
954
955         xfs_trans_ail_destroy(mp);
956
957         xfs_sysfs_del(&mp->m_log->l_kobj);
958
959         xlog_dealloc_log(mp->m_log);
960 }
961
962 void
963 xfs_log_item_init(
964         struct xfs_mount        *mp,
965         struct xfs_log_item     *item,
966         int                     type,
967         const struct xfs_item_ops *ops)
968 {
969         item->li_mountp = mp;
970         item->li_ailp = mp->m_ail;
971         item->li_type = type;
972         item->li_ops = ops;
973         item->li_lv = NULL;
974
975         INIT_LIST_HEAD(&item->li_ail);
976         INIT_LIST_HEAD(&item->li_cil);
977 }
978
979 /*
980  * Wake up processes waiting for log space after we have moved the log tail.
981  */
982 void
983 xfs_log_space_wake(
984         struct xfs_mount        *mp)
985 {
986         struct xlog             *log = mp->m_log;
987         int                     free_bytes;
988
989         if (XLOG_FORCED_SHUTDOWN(log))
990                 return;
991
992         if (!list_empty_careful(&log->l_write_head.waiters)) {
993                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
994
995                 spin_lock(&log->l_write_head.lock);
996                 free_bytes = xlog_space_left(log, &log->l_write_head.grant);
997                 xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
998                 spin_unlock(&log->l_write_head.lock);
999         }
1000
1001         if (!list_empty_careful(&log->l_reserve_head.waiters)) {
1002                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1003
1004                 spin_lock(&log->l_reserve_head.lock);
1005                 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1006                 xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
1007                 spin_unlock(&log->l_reserve_head.lock);
1008         }
1009 }
1010
1011 /*
1012  * Determine if we have a transaction that has gone to disk that needs to be
1013  * covered. To begin the transition to the idle state firstly the log needs to
1014  * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
1015  * we start attempting to cover the log.
1016  *
1017  * Only if we are then in a state where covering is needed, the caller is
1018  * informed that dummy transactions are required to move the log into the idle
1019  * state.
1020  *
1021  * If there are any items in the AIl or CIL, then we do not want to attempt to
1022  * cover the log as we may be in a situation where there isn't log space
1023  * available to run a dummy transaction and this can lead to deadlocks when the
1024  * tail of the log is pinned by an item that is modified in the CIL.  Hence
1025  * there's no point in running a dummy transaction at this point because we
1026  * can't start trying to idle the log until both the CIL and AIL are empty.
1027  */
1028 int
1029 xfs_log_need_covered(xfs_mount_t *mp)
1030 {
1031         struct xlog     *log = mp->m_log;
1032         int             needed = 0;
1033
1034         if (!xfs_fs_writable(mp))
1035                 return 0;
1036
1037         if (!xlog_cil_empty(log))
1038                 return 0;
1039
1040         spin_lock(&log->l_icloglock);
1041         switch (log->l_covered_state) {
1042         case XLOG_STATE_COVER_DONE:
1043         case XLOG_STATE_COVER_DONE2:
1044         case XLOG_STATE_COVER_IDLE:
1045                 break;
1046         case XLOG_STATE_COVER_NEED:
1047         case XLOG_STATE_COVER_NEED2:
1048                 if (xfs_ail_min_lsn(log->l_ailp))
1049                         break;
1050                 if (!xlog_iclogs_empty(log))
1051                         break;
1052
1053                 needed = 1;
1054                 if (log->l_covered_state == XLOG_STATE_COVER_NEED)
1055                         log->l_covered_state = XLOG_STATE_COVER_DONE;
1056                 else
1057                         log->l_covered_state = XLOG_STATE_COVER_DONE2;
1058                 break;
1059         default:
1060                 needed = 1;
1061                 break;
1062         }
1063         spin_unlock(&log->l_icloglock);
1064         return needed;
1065 }
1066
1067 /*
1068  * We may be holding the log iclog lock upon entering this routine.
1069  */
1070 xfs_lsn_t
1071 xlog_assign_tail_lsn_locked(
1072         struct xfs_mount        *mp)
1073 {
1074         struct xlog             *log = mp->m_log;
1075         struct xfs_log_item     *lip;
1076         xfs_lsn_t               tail_lsn;
1077
1078         assert_spin_locked(&mp->m_ail->xa_lock);
1079
1080         /*
1081          * To make sure we always have a valid LSN for the log tail we keep
1082          * track of the last LSN which was committed in log->l_last_sync_lsn,
1083          * and use that when the AIL was empty.
1084          */
1085         lip = xfs_ail_min(mp->m_ail);
1086         if (lip)
1087                 tail_lsn = lip->li_lsn;
1088         else
1089                 tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1090         trace_xfs_log_assign_tail_lsn(log, tail_lsn);
1091         atomic64_set(&log->l_tail_lsn, tail_lsn);
1092         return tail_lsn;
1093 }
1094
1095 xfs_lsn_t
1096 xlog_assign_tail_lsn(
1097         struct xfs_mount        *mp)
1098 {
1099         xfs_lsn_t               tail_lsn;
1100
1101         spin_lock(&mp->m_ail->xa_lock);
1102         tail_lsn = xlog_assign_tail_lsn_locked(mp);
1103         spin_unlock(&mp->m_ail->xa_lock);
1104
1105         return tail_lsn;
1106 }
1107
1108 /*
1109  * Return the space in the log between the tail and the head.  The head
1110  * is passed in the cycle/bytes formal parms.  In the special case where
1111  * the reserve head has wrapped passed the tail, this calculation is no
1112  * longer valid.  In this case, just return 0 which means there is no space
1113  * in the log.  This works for all places where this function is called
1114  * with the reserve head.  Of course, if the write head were to ever
1115  * wrap the tail, we should blow up.  Rather than catch this case here,
1116  * we depend on other ASSERTions in other parts of the code.   XXXmiken
1117  *
1118  * This code also handles the case where the reservation head is behind
1119  * the tail.  The details of this case are described below, but the end
1120  * result is that we return the size of the log as the amount of space left.
1121  */
1122 STATIC int
1123 xlog_space_left(
1124         struct xlog     *log,
1125         atomic64_t      *head)
1126 {
1127         int             free_bytes;
1128         int             tail_bytes;
1129         int             tail_cycle;
1130         int             head_cycle;
1131         int             head_bytes;
1132
1133         xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1134         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1135         tail_bytes = BBTOB(tail_bytes);
1136         if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1137                 free_bytes = log->l_logsize - (head_bytes - tail_bytes);
1138         else if (tail_cycle + 1 < head_cycle)
1139                 return 0;
1140         else if (tail_cycle < head_cycle) {
1141                 ASSERT(tail_cycle == (head_cycle - 1));
1142                 free_bytes = tail_bytes - head_bytes;
1143         } else {
1144                 /*
1145                  * The reservation head is behind the tail.
1146                  * In this case we just want to return the size of the
1147                  * log as the amount of space left.
1148                  */
1149                 xfs_alert(log->l_mp,
1150                         "xlog_space_left: head behind tail\n"
1151                         "  tail_cycle = %d, tail_bytes = %d\n"
1152                         "  GH   cycle = %d, GH   bytes = %d",
1153                         tail_cycle, tail_bytes, head_cycle, head_bytes);
1154                 ASSERT(0);
1155                 free_bytes = log->l_logsize;
1156         }
1157         return free_bytes;
1158 }
1159
1160
1161 /*
1162  * Log function which is called when an io completes.
1163  *
1164  * The log manager needs its own routine, in order to control what
1165  * happens with the buffer after the write completes.
1166  */
1167 void
1168 xlog_iodone(xfs_buf_t *bp)
1169 {
1170         struct xlog_in_core     *iclog = bp->b_fspriv;
1171         struct xlog             *l = iclog->ic_log;
1172         int                     aborted = 0;
1173
1174         /*
1175          * Race to shutdown the filesystem if we see an error.
1176          */
1177         if (XFS_TEST_ERROR(bp->b_error, l->l_mp,
1178                         XFS_ERRTAG_IODONE_IOERR, XFS_RANDOM_IODONE_IOERR)) {
1179                 xfs_buf_ioerror_alert(bp, __func__);
1180                 xfs_buf_stale(bp);
1181                 xfs_force_shutdown(l->l_mp, SHUTDOWN_LOG_IO_ERROR);
1182                 /*
1183                  * This flag will be propagated to the trans-committed
1184                  * callback routines to let them know that the log-commit
1185                  * didn't succeed.
1186                  */
1187                 aborted = XFS_LI_ABORTED;
1188         } else if (iclog->ic_state & XLOG_STATE_IOERROR) {
1189                 aborted = XFS_LI_ABORTED;
1190         }
1191
1192         /* log I/O is always issued ASYNC */
1193         ASSERT(XFS_BUF_ISASYNC(bp));
1194         xlog_state_done_syncing(iclog, aborted);
1195
1196         /*
1197          * drop the buffer lock now that we are done. Nothing references
1198          * the buffer after this, so an unmount waiting on this lock can now
1199          * tear it down safely. As such, it is unsafe to reference the buffer
1200          * (bp) after the unlock as we could race with it being freed.
1201          */
1202         xfs_buf_unlock(bp);
1203 }
1204
1205 /*
1206  * Return size of each in-core log record buffer.
1207  *
1208  * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1209  *
1210  * If the filesystem blocksize is too large, we may need to choose a
1211  * larger size since the directory code currently logs entire blocks.
1212  */
1213
1214 STATIC void
1215 xlog_get_iclog_buffer_size(
1216         struct xfs_mount        *mp,
1217         struct xlog             *log)
1218 {
1219         int size;
1220         int xhdrs;
1221
1222         if (mp->m_logbufs <= 0)
1223                 log->l_iclog_bufs = XLOG_MAX_ICLOGS;
1224         else
1225                 log->l_iclog_bufs = mp->m_logbufs;
1226
1227         /*
1228          * Buffer size passed in from mount system call.
1229          */
1230         if (mp->m_logbsize > 0) {
1231                 size = log->l_iclog_size = mp->m_logbsize;
1232                 log->l_iclog_size_log = 0;
1233                 while (size != 1) {
1234                         log->l_iclog_size_log++;
1235                         size >>= 1;
1236                 }
1237
1238                 if (xfs_sb_version_haslogv2(&mp->m_sb)) {
1239                         /* # headers = size / 32k
1240                          * one header holds cycles from 32k of data
1241                          */
1242
1243                         xhdrs = mp->m_logbsize / XLOG_HEADER_CYCLE_SIZE;
1244                         if (mp->m_logbsize % XLOG_HEADER_CYCLE_SIZE)
1245                                 xhdrs++;
1246                         log->l_iclog_hsize = xhdrs << BBSHIFT;
1247                         log->l_iclog_heads = xhdrs;
1248                 } else {
1249                         ASSERT(mp->m_logbsize <= XLOG_BIG_RECORD_BSIZE);
1250                         log->l_iclog_hsize = BBSIZE;
1251                         log->l_iclog_heads = 1;
1252                 }
1253                 goto done;
1254         }
1255
1256         /* All machines use 32kB buffers by default. */
1257         log->l_iclog_size = XLOG_BIG_RECORD_BSIZE;
1258         log->l_iclog_size_log = XLOG_BIG_RECORD_BSHIFT;
1259
1260         /* the default log size is 16k or 32k which is one header sector */
1261         log->l_iclog_hsize = BBSIZE;
1262         log->l_iclog_heads = 1;
1263
1264 done:
1265         /* are we being asked to make the sizes selected above visible? */
1266         if (mp->m_logbufs == 0)
1267                 mp->m_logbufs = log->l_iclog_bufs;
1268         if (mp->m_logbsize == 0)
1269                 mp->m_logbsize = log->l_iclog_size;
1270 }       /* xlog_get_iclog_buffer_size */
1271
1272
1273 void
1274 xfs_log_work_queue(
1275         struct xfs_mount        *mp)
1276 {
1277         queue_delayed_work(mp->m_log_workqueue, &mp->m_log->l_work,
1278                                 msecs_to_jiffies(xfs_syncd_centisecs * 10));
1279 }
1280
1281 /*
1282  * Every sync period we need to unpin all items in the AIL and push them to
1283  * disk. If there is nothing dirty, then we might need to cover the log to
1284  * indicate that the filesystem is idle.
1285  */
1286 void
1287 xfs_log_worker(
1288         struct work_struct      *work)
1289 {
1290         struct xlog             *log = container_of(to_delayed_work(work),
1291                                                 struct xlog, l_work);
1292         struct xfs_mount        *mp = log->l_mp;
1293
1294         /* dgc: errors ignored - not fatal and nowhere to report them */
1295         if (xfs_log_need_covered(mp))
1296                 xfs_fs_log_dummy(mp);
1297         else
1298                 xfs_log_force(mp, 0);
1299
1300         /* start pushing all the metadata that is currently dirty */
1301         xfs_ail_push_all(mp->m_ail);
1302
1303         /* queue us up again */
1304         xfs_log_work_queue(mp);
1305 }
1306
1307 /*
1308  * This routine initializes some of the log structure for a given mount point.
1309  * Its primary purpose is to fill in enough, so recovery can occur.  However,
1310  * some other stuff may be filled in too.
1311  */
1312 STATIC struct xlog *
1313 xlog_alloc_log(
1314         struct xfs_mount        *mp,
1315         struct xfs_buftarg      *log_target,
1316         xfs_daddr_t             blk_offset,
1317         int                     num_bblks)
1318 {
1319         struct xlog             *log;
1320         xlog_rec_header_t       *head;
1321         xlog_in_core_t          **iclogp;
1322         xlog_in_core_t          *iclog, *prev_iclog=NULL;
1323         xfs_buf_t               *bp;
1324         int                     i;
1325         int                     error = -ENOMEM;
1326         uint                    log2_size = 0;
1327
1328         log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1329         if (!log) {
1330                 xfs_warn(mp, "Log allocation failed: No memory!");
1331                 goto out;
1332         }
1333
1334         log->l_mp          = mp;
1335         log->l_targ        = log_target;
1336         log->l_logsize     = BBTOB(num_bblks);
1337         log->l_logBBstart  = blk_offset;
1338         log->l_logBBsize   = num_bblks;
1339         log->l_covered_state = XLOG_STATE_COVER_IDLE;
1340         log->l_flags       |= XLOG_ACTIVE_RECOVERY;
1341         INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1342
1343         log->l_prev_block  = -1;
1344         /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1345         xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1346         xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1347         log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
1348
1349         xlog_grant_head_init(&log->l_reserve_head);
1350         xlog_grant_head_init(&log->l_write_head);
1351
1352         error = -EFSCORRUPTED;
1353         if (xfs_sb_version_hassector(&mp->m_sb)) {
1354                 log2_size = mp->m_sb.sb_logsectlog;
1355                 if (log2_size < BBSHIFT) {
1356                         xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1357                                 log2_size, BBSHIFT);
1358                         goto out_free_log;
1359                 }
1360
1361                 log2_size -= BBSHIFT;
1362                 if (log2_size > mp->m_sectbb_log) {
1363                         xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1364                                 log2_size, mp->m_sectbb_log);
1365                         goto out_free_log;
1366                 }
1367
1368                 /* for larger sector sizes, must have v2 or external log */
1369                 if (log2_size && log->l_logBBstart > 0 &&
1370                             !xfs_sb_version_haslogv2(&mp->m_sb)) {
1371                         xfs_warn(mp,
1372                 "log sector size (0x%x) invalid for configuration.",
1373                                 log2_size);
1374                         goto out_free_log;
1375                 }
1376         }
1377         log->l_sectBBsize = 1 << log2_size;
1378
1379         xlog_get_iclog_buffer_size(mp, log);
1380
1381         /*
1382          * Use a NULL block for the extra log buffer used during splits so that
1383          * it will trigger errors if we ever try to do IO on it without first
1384          * having set it up properly.
1385          */
1386         error = -ENOMEM;
1387         bp = xfs_buf_alloc(mp->m_logdev_targp, XFS_BUF_DADDR_NULL,
1388                            BTOBB(log->l_iclog_size), 0);
1389         if (!bp)
1390                 goto out_free_log;
1391
1392         /*
1393          * The iclogbuf buffer locks are held over IO but we are not going to do
1394          * IO yet.  Hence unlock the buffer so that the log IO path can grab it
1395          * when appropriately.
1396          */
1397         ASSERT(xfs_buf_islocked(bp));
1398         xfs_buf_unlock(bp);
1399
1400         bp->b_iodone = xlog_iodone;
1401         log->l_xbuf = bp;
1402
1403         spin_lock_init(&log->l_icloglock);
1404         init_waitqueue_head(&log->l_flush_wait);
1405
1406         iclogp = &log->l_iclog;
1407         /*
1408          * The amount of memory to allocate for the iclog structure is
1409          * rather funky due to the way the structure is defined.  It is
1410          * done this way so that we can use different sizes for machines
1411          * with different amounts of memory.  See the definition of
1412          * xlog_in_core_t in xfs_log_priv.h for details.
1413          */
1414         ASSERT(log->l_iclog_size >= 4096);
1415         for (i=0; i < log->l_iclog_bufs; i++) {
1416                 *iclogp = kmem_zalloc(sizeof(xlog_in_core_t), KM_MAYFAIL);
1417                 if (!*iclogp)
1418                         goto out_free_iclog;
1419
1420                 iclog = *iclogp;
1421                 iclog->ic_prev = prev_iclog;
1422                 prev_iclog = iclog;
1423
1424                 bp = xfs_buf_get_uncached(mp->m_logdev_targp,
1425                                                 BTOBB(log->l_iclog_size), 0);
1426                 if (!bp)
1427                         goto out_free_iclog;
1428
1429                 ASSERT(xfs_buf_islocked(bp));
1430                 xfs_buf_unlock(bp);
1431
1432                 bp->b_iodone = xlog_iodone;
1433                 iclog->ic_bp = bp;
1434                 iclog->ic_data = bp->b_addr;
1435 #ifdef DEBUG
1436                 log->l_iclog_bak[i] = (xfs_caddr_t)&(iclog->ic_header);
1437 #endif
1438                 head = &iclog->ic_header;
1439                 memset(head, 0, sizeof(xlog_rec_header_t));
1440                 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1441                 head->h_version = cpu_to_be32(
1442                         xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1443                 head->h_size = cpu_to_be32(log->l_iclog_size);
1444                 /* new fields */
1445                 head->h_fmt = cpu_to_be32(XLOG_FMT);
1446                 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1447
1448                 iclog->ic_size = BBTOB(bp->b_length) - log->l_iclog_hsize;
1449                 iclog->ic_state = XLOG_STATE_ACTIVE;
1450                 iclog->ic_log = log;
1451                 atomic_set(&iclog->ic_refcnt, 0);
1452                 spin_lock_init(&iclog->ic_callback_lock);
1453                 iclog->ic_callback_tail = &(iclog->ic_callback);
1454                 iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1455
1456                 init_waitqueue_head(&iclog->ic_force_wait);
1457                 init_waitqueue_head(&iclog->ic_write_wait);
1458
1459                 iclogp = &iclog->ic_next;
1460         }
1461         *iclogp = log->l_iclog;                 /* complete ring */
1462         log->l_iclog->ic_prev = prev_iclog;     /* re-write 1st prev ptr */
1463
1464         error = xlog_cil_init(log);
1465         if (error)
1466                 goto out_free_iclog;
1467         return log;
1468
1469 out_free_iclog:
1470         for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1471                 prev_iclog = iclog->ic_next;
1472                 if (iclog->ic_bp)
1473                         xfs_buf_free(iclog->ic_bp);
1474                 kmem_free(iclog);
1475         }
1476         spinlock_destroy(&log->l_icloglock);
1477         xfs_buf_free(log->l_xbuf);
1478 out_free_log:
1479         kmem_free(log);
1480 out:
1481         return ERR_PTR(error);
1482 }       /* xlog_alloc_log */
1483
1484
1485 /*
1486  * Write out the commit record of a transaction associated with the given
1487  * ticket.  Return the lsn of the commit record.
1488  */
1489 STATIC int
1490 xlog_commit_record(
1491         struct xlog             *log,
1492         struct xlog_ticket      *ticket,
1493         struct xlog_in_core     **iclog,
1494         xfs_lsn_t               *commitlsnp)
1495 {
1496         struct xfs_mount *mp = log->l_mp;
1497         int     error;
1498         struct xfs_log_iovec reg = {
1499                 .i_addr = NULL,
1500                 .i_len = 0,
1501                 .i_type = XLOG_REG_TYPE_COMMIT,
1502         };
1503         struct xfs_log_vec vec = {
1504                 .lv_niovecs = 1,
1505                 .lv_iovecp = &reg,
1506         };
1507
1508         ASSERT_ALWAYS(iclog);
1509         error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
1510                                         XLOG_COMMIT_TRANS);
1511         if (error)
1512                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
1513         return error;
1514 }
1515
1516 /*
1517  * Push on the buffer cache code if we ever use more than 75% of the on-disk
1518  * log space.  This code pushes on the lsn which would supposedly free up
1519  * the 25% which we want to leave free.  We may need to adopt a policy which
1520  * pushes on an lsn which is further along in the log once we reach the high
1521  * water mark.  In this manner, we would be creating a low water mark.
1522  */
1523 STATIC void
1524 xlog_grant_push_ail(
1525         struct xlog     *log,
1526         int             need_bytes)
1527 {
1528         xfs_lsn_t       threshold_lsn = 0;
1529         xfs_lsn_t       last_sync_lsn;
1530         int             free_blocks;
1531         int             free_bytes;
1532         int             threshold_block;
1533         int             threshold_cycle;
1534         int             free_threshold;
1535
1536         ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1537
1538         free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1539         free_blocks = BTOBBT(free_bytes);
1540
1541         /*
1542          * Set the threshold for the minimum number of free blocks in the
1543          * log to the maximum of what the caller needs, one quarter of the
1544          * log, and 256 blocks.
1545          */
1546         free_threshold = BTOBB(need_bytes);
1547         free_threshold = MAX(free_threshold, (log->l_logBBsize >> 2));
1548         free_threshold = MAX(free_threshold, 256);
1549         if (free_blocks >= free_threshold)
1550                 return;
1551
1552         xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1553                                                 &threshold_block);
1554         threshold_block += free_threshold;
1555         if (threshold_block >= log->l_logBBsize) {
1556                 threshold_block -= log->l_logBBsize;
1557                 threshold_cycle += 1;
1558         }
1559         threshold_lsn = xlog_assign_lsn(threshold_cycle,
1560                                         threshold_block);
1561         /*
1562          * Don't pass in an lsn greater than the lsn of the last
1563          * log record known to be on disk. Use a snapshot of the last sync lsn
1564          * so that it doesn't change between the compare and the set.
1565          */
1566         last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1567         if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1568                 threshold_lsn = last_sync_lsn;
1569
1570         /*
1571          * Get the transaction layer to kick the dirty buffers out to
1572          * disk asynchronously. No point in trying to do this if
1573          * the filesystem is shutting down.
1574          */
1575         if (!XLOG_FORCED_SHUTDOWN(log))
1576                 xfs_ail_push(log->l_ailp, threshold_lsn);
1577 }
1578
1579 /*
1580  * Stamp cycle number in every block
1581  */
1582 STATIC void
1583 xlog_pack_data(
1584         struct xlog             *log,
1585         struct xlog_in_core     *iclog,
1586         int                     roundoff)
1587 {
1588         int                     i, j, k;
1589         int                     size = iclog->ic_offset + roundoff;
1590         __be32                  cycle_lsn;
1591         xfs_caddr_t             dp;
1592
1593         cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1594
1595         dp = iclog->ic_datap;
1596         for (i = 0; i < BTOBB(size); i++) {
1597                 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1598                         break;
1599                 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1600                 *(__be32 *)dp = cycle_lsn;
1601                 dp += BBSIZE;
1602         }
1603
1604         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1605                 xlog_in_core_2_t *xhdr = iclog->ic_data;
1606
1607                 for ( ; i < BTOBB(size); i++) {
1608                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1609                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1610                         xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1611                         *(__be32 *)dp = cycle_lsn;
1612                         dp += BBSIZE;
1613                 }
1614
1615                 for (i = 1; i < log->l_iclog_heads; i++)
1616                         xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1617         }
1618 }
1619
1620 /*
1621  * Calculate the checksum for a log buffer.
1622  *
1623  * This is a little more complicated than it should be because the various
1624  * headers and the actual data are non-contiguous.
1625  */
1626 __le32
1627 xlog_cksum(
1628         struct xlog             *log,
1629         struct xlog_rec_header  *rhead,
1630         char                    *dp,
1631         int                     size)
1632 {
1633         __uint32_t              crc;
1634
1635         /* first generate the crc for the record header ... */
1636         crc = xfs_start_cksum((char *)rhead,
1637                               sizeof(struct xlog_rec_header),
1638                               offsetof(struct xlog_rec_header, h_crc));
1639
1640         /* ... then for additional cycle data for v2 logs ... */
1641         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1642                 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1643                 int             i;
1644
1645                 for (i = 1; i < log->l_iclog_heads; i++) {
1646                         crc = crc32c(crc, &xhdr[i].hic_xheader,
1647                                      sizeof(struct xlog_rec_ext_header));
1648                 }
1649         }
1650
1651         /* ... and finally for the payload */
1652         crc = crc32c(crc, dp, size);
1653
1654         return xfs_end_cksum(crc);
1655 }
1656
1657 /*
1658  * The bdstrat callback function for log bufs. This gives us a central
1659  * place to trap bufs in case we get hit by a log I/O error and need to
1660  * shutdown. Actually, in practice, even when we didn't get a log error,
1661  * we transition the iclogs to IOERROR state *after* flushing all existing
1662  * iclogs to disk. This is because we don't want anymore new transactions to be
1663  * started or completed afterwards.
1664  *
1665  * We lock the iclogbufs here so that we can serialise against IO completion
1666  * during unmount. We might be processing a shutdown triggered during unmount,
1667  * and that can occur asynchronously to the unmount thread, and hence we need to
1668  * ensure that completes before tearing down the iclogbufs. Hence we need to
1669  * hold the buffer lock across the log IO to acheive that.
1670  */
1671 STATIC int
1672 xlog_bdstrat(
1673         struct xfs_buf          *bp)
1674 {
1675         struct xlog_in_core     *iclog = bp->b_fspriv;
1676
1677         xfs_buf_lock(bp);
1678         if (iclog->ic_state & XLOG_STATE_IOERROR) {
1679                 xfs_buf_ioerror(bp, -EIO);
1680                 xfs_buf_stale(bp);
1681                 xfs_buf_ioend(bp);
1682                 /*
1683                  * It would seem logical to return EIO here, but we rely on
1684                  * the log state machine to propagate I/O errors instead of
1685                  * doing it here. Similarly, IO completion will unlock the
1686                  * buffer, so we don't do it here.
1687                  */
1688                 return 0;
1689         }
1690
1691         xfs_buf_submit(bp);
1692         return 0;
1693 }
1694
1695 /*
1696  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous 
1697  * fashion.  Previously, we should have moved the current iclog
1698  * ptr in the log to point to the next available iclog.  This allows further
1699  * write to continue while this code syncs out an iclog ready to go.
1700  * Before an in-core log can be written out, the data section must be scanned
1701  * to save away the 1st word of each BBSIZE block into the header.  We replace
1702  * it with the current cycle count.  Each BBSIZE block is tagged with the
1703  * cycle count because there in an implicit assumption that drives will
1704  * guarantee that entire 512 byte blocks get written at once.  In other words,
1705  * we can't have part of a 512 byte block written and part not written.  By
1706  * tagging each block, we will know which blocks are valid when recovering
1707  * after an unclean shutdown.
1708  *
1709  * This routine is single threaded on the iclog.  No other thread can be in
1710  * this routine with the same iclog.  Changing contents of iclog can there-
1711  * fore be done without grabbing the state machine lock.  Updating the global
1712  * log will require grabbing the lock though.
1713  *
1714  * The entire log manager uses a logical block numbering scheme.  Only
1715  * log_sync (and then only bwrite()) know about the fact that the log may
1716  * not start with block zero on a given device.  The log block start offset
1717  * is added immediately before calling bwrite().
1718  */
1719
1720 STATIC int
1721 xlog_sync(
1722         struct xlog             *log,
1723         struct xlog_in_core     *iclog)
1724 {
1725         xfs_buf_t       *bp;
1726         int             i;
1727         uint            count;          /* byte count of bwrite */
1728         uint            count_init;     /* initial count before roundup */
1729         int             roundoff;       /* roundoff to BB or stripe */
1730         int             split = 0;      /* split write into two regions */
1731         int             error;
1732         int             v2 = xfs_sb_version_haslogv2(&log->l_mp->m_sb);
1733         int             size;
1734
1735         XFS_STATS_INC(xs_log_writes);
1736         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1737
1738         /* Add for LR header */
1739         count_init = log->l_iclog_hsize + iclog->ic_offset;
1740
1741         /* Round out the log write size */
1742         if (v2 && log->l_mp->m_sb.sb_logsunit > 1) {
1743                 /* we have a v2 stripe unit to use */
1744                 count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1745         } else {
1746                 count = BBTOB(BTOBB(count_init));
1747         }
1748         roundoff = count - count_init;
1749         ASSERT(roundoff >= 0);
1750         ASSERT((v2 && log->l_mp->m_sb.sb_logsunit > 1 && 
1751                 roundoff < log->l_mp->m_sb.sb_logsunit)
1752                 || 
1753                 (log->l_mp->m_sb.sb_logsunit <= 1 && 
1754                  roundoff < BBTOB(1)));
1755
1756         /* move grant heads by roundoff in sync */
1757         xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1758         xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1759
1760         /* put cycle number in every block */
1761         xlog_pack_data(log, iclog, roundoff); 
1762
1763         /* real byte length */
1764         size = iclog->ic_offset;
1765         if (v2)
1766                 size += roundoff;
1767         iclog->ic_header.h_len = cpu_to_be32(size);
1768
1769         bp = iclog->ic_bp;
1770         XFS_BUF_SET_ADDR(bp, BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn)));
1771
1772         XFS_STATS_ADD(xs_log_blocks, BTOBB(count));
1773
1774         /* Do we need to split this write into 2 parts? */
1775         if (XFS_BUF_ADDR(bp) + BTOBB(count) > log->l_logBBsize) {
1776                 char            *dptr;
1777
1778                 split = count - (BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp)));
1779                 count = BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp));
1780                 iclog->ic_bwritecnt = 2;
1781
1782                 /*
1783                  * Bump the cycle numbers at the start of each block in the
1784                  * part of the iclog that ends up in the buffer that gets
1785                  * written to the start of the log.
1786                  *
1787                  * Watch out for the header magic number case, though.
1788                  */
1789                 dptr = (char *)&iclog->ic_header + count;
1790                 for (i = 0; i < split; i += BBSIZE) {
1791                         __uint32_t cycle = be32_to_cpu(*(__be32 *)dptr);
1792                         if (++cycle == XLOG_HEADER_MAGIC_NUM)
1793                                 cycle++;
1794                         *(__be32 *)dptr = cpu_to_be32(cycle);
1795
1796                         dptr += BBSIZE;
1797                 }
1798         } else {
1799                 iclog->ic_bwritecnt = 1;
1800         }
1801
1802         /* calculcate the checksum */
1803         iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1804                                             iclog->ic_datap, size);
1805
1806         bp->b_io_length = BTOBB(count);
1807         bp->b_fspriv = iclog;
1808         XFS_BUF_ZEROFLAGS(bp);
1809         XFS_BUF_ASYNC(bp);
1810         bp->b_flags |= XBF_SYNCIO;
1811
1812         if (log->l_mp->m_flags & XFS_MOUNT_BARRIER) {
1813                 bp->b_flags |= XBF_FUA;
1814
1815                 /*
1816                  * Flush the data device before flushing the log to make
1817                  * sure all meta data written back from the AIL actually made
1818                  * it to disk before stamping the new log tail LSN into the
1819                  * log buffer.  For an external log we need to issue the
1820                  * flush explicitly, and unfortunately synchronously here;
1821                  * for an internal log we can simply use the block layer
1822                  * state machine for preflushes.
1823                  */
1824                 if (log->l_mp->m_logdev_targp != log->l_mp->m_ddev_targp)
1825                         xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
1826                 else
1827                         bp->b_flags |= XBF_FLUSH;
1828         }
1829
1830         ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
1831         ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
1832
1833         xlog_verify_iclog(log, iclog, count, true);
1834
1835         /* account for log which doesn't start at block #0 */
1836         XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
1837         /*
1838          * Don't call xfs_bwrite here. We do log-syncs even when the filesystem
1839          * is shutting down.
1840          */
1841         XFS_BUF_WRITE(bp);
1842
1843         error = xlog_bdstrat(bp);
1844         if (error) {
1845                 xfs_buf_ioerror_alert(bp, "xlog_sync");
1846                 return error;
1847         }
1848         if (split) {
1849                 bp = iclog->ic_log->l_xbuf;
1850                 XFS_BUF_SET_ADDR(bp, 0);             /* logical 0 */
1851                 xfs_buf_associate_memory(bp,
1852                                 (char *)&iclog->ic_header + count, split);
1853                 bp->b_fspriv = iclog;
1854                 XFS_BUF_ZEROFLAGS(bp);
1855                 XFS_BUF_ASYNC(bp);
1856                 bp->b_flags |= XBF_SYNCIO;
1857                 if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
1858                         bp->b_flags |= XBF_FUA;
1859
1860                 ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
1861                 ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
1862
1863                 /* account for internal log which doesn't start at block #0 */
1864                 XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
1865                 XFS_BUF_WRITE(bp);
1866                 error = xlog_bdstrat(bp);
1867                 if (error) {
1868                         xfs_buf_ioerror_alert(bp, "xlog_sync (split)");
1869                         return error;
1870                 }
1871         }
1872         return 0;
1873 }       /* xlog_sync */
1874
1875 /*
1876  * Deallocate a log structure
1877  */
1878 STATIC void
1879 xlog_dealloc_log(
1880         struct xlog     *log)
1881 {
1882         xlog_in_core_t  *iclog, *next_iclog;
1883         int             i;
1884
1885         xlog_cil_destroy(log);
1886
1887         /*
1888          * Cycle all the iclogbuf locks to make sure all log IO completion
1889          * is done before we tear down these buffers.
1890          */
1891         iclog = log->l_iclog;
1892         for (i = 0; i < log->l_iclog_bufs; i++) {
1893                 xfs_buf_lock(iclog->ic_bp);
1894                 xfs_buf_unlock(iclog->ic_bp);
1895                 iclog = iclog->ic_next;
1896         }
1897
1898         /*
1899          * Always need to ensure that the extra buffer does not point to memory
1900          * owned by another log buffer before we free it. Also, cycle the lock
1901          * first to ensure we've completed IO on it.
1902          */
1903         xfs_buf_lock(log->l_xbuf);
1904         xfs_buf_unlock(log->l_xbuf);
1905         xfs_buf_set_empty(log->l_xbuf, BTOBB(log->l_iclog_size));
1906         xfs_buf_free(log->l_xbuf);
1907
1908         iclog = log->l_iclog;
1909         for (i = 0; i < log->l_iclog_bufs; i++) {
1910                 xfs_buf_free(iclog->ic_bp);
1911                 next_iclog = iclog->ic_next;
1912                 kmem_free(iclog);
1913                 iclog = next_iclog;
1914         }
1915         spinlock_destroy(&log->l_icloglock);
1916
1917         log->l_mp->m_log = NULL;
1918         kmem_free(log);
1919 }       /* xlog_dealloc_log */
1920
1921 /*
1922  * Update counters atomically now that memcpy is done.
1923  */
1924 /* ARGSUSED */
1925 static inline void
1926 xlog_state_finish_copy(
1927         struct xlog             *log,
1928         struct xlog_in_core     *iclog,
1929         int                     record_cnt,
1930         int                     copy_bytes)
1931 {
1932         spin_lock(&log->l_icloglock);
1933
1934         be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1935         iclog->ic_offset += copy_bytes;
1936
1937         spin_unlock(&log->l_icloglock);
1938 }       /* xlog_state_finish_copy */
1939
1940
1941
1942
1943 /*
1944  * print out info relating to regions written which consume
1945  * the reservation
1946  */
1947 void
1948 xlog_print_tic_res(
1949         struct xfs_mount        *mp,
1950         struct xlog_ticket      *ticket)
1951 {
1952         uint i;
1953         uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
1954
1955         /* match with XLOG_REG_TYPE_* in xfs_log.h */
1956         static char *res_type_str[XLOG_REG_TYPE_MAX] = {
1957             "bformat",
1958             "bchunk",
1959             "efi_format",
1960             "efd_format",
1961             "iformat",
1962             "icore",
1963             "iext",
1964             "ibroot",
1965             "ilocal",
1966             "iattr_ext",
1967             "iattr_broot",
1968             "iattr_local",
1969             "qformat",
1970             "dquot",
1971             "quotaoff",
1972             "LR header",
1973             "unmount",
1974             "commit",
1975             "trans header"
1976         };
1977         static char *trans_type_str[XFS_TRANS_TYPE_MAX] = {
1978             "SETATTR_NOT_SIZE",
1979             "SETATTR_SIZE",
1980             "INACTIVE",
1981             "CREATE",
1982             "CREATE_TRUNC",
1983             "TRUNCATE_FILE",
1984             "REMOVE",
1985             "LINK",
1986             "RENAME",
1987             "MKDIR",
1988             "RMDIR",
1989             "SYMLINK",
1990             "SET_DMATTRS",
1991             "GROWFS",
1992             "STRAT_WRITE",
1993             "DIOSTRAT",
1994             "WRITE_SYNC",
1995             "WRITEID",
1996             "ADDAFORK",
1997             "ATTRINVAL",
1998             "ATRUNCATE",
1999             "ATTR_SET",
2000             "ATTR_RM",
2001             "ATTR_FLAG",
2002             "CLEAR_AGI_BUCKET",
2003             "QM_SBCHANGE",
2004             "DUMMY1",
2005             "DUMMY2",
2006             "QM_QUOTAOFF",
2007             "QM_DQALLOC",
2008             "QM_SETQLIM",
2009             "QM_DQCLUSTER",
2010             "QM_QINOCREATE",
2011             "QM_QUOTAOFF_END",
2012             "SB_UNIT",
2013             "FSYNC_TS",
2014             "GROWFSRT_ALLOC",
2015             "GROWFSRT_ZERO",
2016             "GROWFSRT_FREE",
2017             "SWAPEXT"
2018         };
2019
2020         xfs_warn(mp,
2021                 "xlog_write: reservation summary:\n"
2022                 "  trans type  = %s (%u)\n"
2023                 "  unit res    = %d bytes\n"
2024                 "  current res = %d bytes\n"
2025                 "  total reg   = %u bytes (o/flow = %u bytes)\n"
2026                 "  ophdrs      = %u (ophdr space = %u bytes)\n"
2027                 "  ophdr + reg = %u bytes\n"
2028                 "  num regions = %u\n",
2029                 ((ticket->t_trans_type <= 0 ||
2030                   ticket->t_trans_type > XFS_TRANS_TYPE_MAX) ?
2031                   "bad-trans-type" : trans_type_str[ticket->t_trans_type-1]),
2032                 ticket->t_trans_type,
2033                 ticket->t_unit_res,
2034                 ticket->t_curr_res,
2035                 ticket->t_res_arr_sum, ticket->t_res_o_flow,
2036                 ticket->t_res_num_ophdrs, ophdr_spc,
2037                 ticket->t_res_arr_sum +
2038                 ticket->t_res_o_flow + ophdr_spc,
2039                 ticket->t_res_num);
2040
2041         for (i = 0; i < ticket->t_res_num; i++) {
2042                 uint r_type = ticket->t_res_arr[i].r_type;
2043                 xfs_warn(mp, "region[%u]: %s - %u bytes", i,
2044                             ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
2045                             "bad-rtype" : res_type_str[r_type-1]),
2046                             ticket->t_res_arr[i].r_len);
2047         }
2048
2049         xfs_alert_tag(mp, XFS_PTAG_LOGRES,
2050                 "xlog_write: reservation ran out. Need to up reservation");
2051         xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
2052 }
2053
2054 /*
2055  * Calculate the potential space needed by the log vector.  Each region gets
2056  * its own xlog_op_header_t and may need to be double word aligned.
2057  */
2058 static int
2059 xlog_write_calc_vec_length(
2060         struct xlog_ticket      *ticket,
2061         struct xfs_log_vec      *log_vector)
2062 {
2063         struct xfs_log_vec      *lv;
2064         int                     headers = 0;
2065         int                     len = 0;
2066         int                     i;
2067
2068         /* acct for start rec of xact */
2069         if (ticket->t_flags & XLOG_TIC_INITED)
2070                 headers++;
2071
2072         for (lv = log_vector; lv; lv = lv->lv_next) {
2073                 /* we don't write ordered log vectors */
2074                 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
2075                         continue;
2076
2077                 headers += lv->lv_niovecs;
2078
2079                 for (i = 0; i < lv->lv_niovecs; i++) {
2080                         struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
2081
2082                         len += vecp->i_len;
2083                         xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
2084                 }
2085         }
2086
2087         ticket->t_res_num_ophdrs += headers;
2088         len += headers * sizeof(struct xlog_op_header);
2089
2090         return len;
2091 }
2092
2093 /*
2094  * If first write for transaction, insert start record  We can't be trying to
2095  * commit if we are inited.  We can't have any "partial_copy" if we are inited.
2096  */
2097 static int
2098 xlog_write_start_rec(
2099         struct xlog_op_header   *ophdr,
2100         struct xlog_ticket      *ticket)
2101 {
2102         if (!(ticket->t_flags & XLOG_TIC_INITED))
2103                 return 0;
2104
2105         ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
2106         ophdr->oh_clientid = ticket->t_clientid;
2107         ophdr->oh_len = 0;
2108         ophdr->oh_flags = XLOG_START_TRANS;
2109         ophdr->oh_res2 = 0;
2110
2111         ticket->t_flags &= ~XLOG_TIC_INITED;
2112
2113         return sizeof(struct xlog_op_header);
2114 }
2115
2116 static xlog_op_header_t *
2117 xlog_write_setup_ophdr(
2118         struct xlog             *log,
2119         struct xlog_op_header   *ophdr,
2120         struct xlog_ticket      *ticket,
2121         uint                    flags)
2122 {
2123         ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2124         ophdr->oh_clientid = ticket->t_clientid;
2125         ophdr->oh_res2 = 0;
2126
2127         /* are we copying a commit or unmount record? */
2128         ophdr->oh_flags = flags;
2129
2130         /*
2131          * We've seen logs corrupted with bad transaction client ids.  This
2132          * makes sure that XFS doesn't generate them on.  Turn this into an EIO
2133          * and shut down the filesystem.
2134          */
2135         switch (ophdr->oh_clientid)  {
2136         case XFS_TRANSACTION:
2137         case XFS_VOLUME:
2138         case XFS_LOG:
2139                 break;
2140         default:
2141                 xfs_warn(log->l_mp,
2142                         "Bad XFS transaction clientid 0x%x in ticket 0x%p",
2143                         ophdr->oh_clientid, ticket);
2144                 return NULL;
2145         }
2146
2147         return ophdr;
2148 }
2149
2150 /*
2151  * Set up the parameters of the region copy into the log. This has
2152  * to handle region write split across multiple log buffers - this
2153  * state is kept external to this function so that this code can
2154  * be written in an obvious, self documenting manner.
2155  */
2156 static int
2157 xlog_write_setup_copy(
2158         struct xlog_ticket      *ticket,
2159         struct xlog_op_header   *ophdr,
2160         int                     space_available,
2161         int                     space_required,
2162         int                     *copy_off,
2163         int                     *copy_len,
2164         int                     *last_was_partial_copy,
2165         int                     *bytes_consumed)
2166 {
2167         int                     still_to_copy;
2168
2169         still_to_copy = space_required - *bytes_consumed;
2170         *copy_off = *bytes_consumed;
2171
2172         if (still_to_copy <= space_available) {
2173                 /* write of region completes here */
2174                 *copy_len = still_to_copy;
2175                 ophdr->oh_len = cpu_to_be32(*copy_len);
2176                 if (*last_was_partial_copy)
2177                         ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2178                 *last_was_partial_copy = 0;
2179                 *bytes_consumed = 0;
2180                 return 0;
2181         }
2182
2183         /* partial write of region, needs extra log op header reservation */
2184         *copy_len = space_available;
2185         ophdr->oh_len = cpu_to_be32(*copy_len);
2186         ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2187         if (*last_was_partial_copy)
2188                 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2189         *bytes_consumed += *copy_len;
2190         (*last_was_partial_copy)++;
2191
2192         /* account for new log op header */
2193         ticket->t_curr_res -= sizeof(struct xlog_op_header);
2194         ticket->t_res_num_ophdrs++;
2195
2196         return sizeof(struct xlog_op_header);
2197 }
2198
2199 static int
2200 xlog_write_copy_finish(
2201         struct xlog             *log,
2202         struct xlog_in_core     *iclog,
2203         uint                    flags,
2204         int                     *record_cnt,
2205         int                     *data_cnt,
2206         int                     *partial_copy,
2207         int                     *partial_copy_len,
2208         int                     log_offset,
2209         struct xlog_in_core     **commit_iclog)
2210 {
2211         if (*partial_copy) {
2212                 /*
2213                  * This iclog has already been marked WANT_SYNC by
2214                  * xlog_state_get_iclog_space.
2215                  */
2216                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2217                 *record_cnt = 0;
2218                 *data_cnt = 0;
2219                 return xlog_state_release_iclog(log, iclog);
2220         }
2221
2222         *partial_copy = 0;
2223         *partial_copy_len = 0;
2224
2225         if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2226                 /* no more space in this iclog - push it. */
2227                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2228                 *record_cnt = 0;
2229                 *data_cnt = 0;
2230
2231                 spin_lock(&log->l_icloglock);
2232                 xlog_state_want_sync(log, iclog);
2233                 spin_unlock(&log->l_icloglock);
2234
2235                 if (!commit_iclog)
2236                         return xlog_state_release_iclog(log, iclog);
2237                 ASSERT(flags & XLOG_COMMIT_TRANS);
2238                 *commit_iclog = iclog;
2239         }
2240
2241         return 0;
2242 }
2243
2244 /*
2245  * Write some region out to in-core log
2246  *
2247  * This will be called when writing externally provided regions or when
2248  * writing out a commit record for a given transaction.
2249  *
2250  * General algorithm:
2251  *      1. Find total length of this write.  This may include adding to the
2252  *              lengths passed in.
2253  *      2. Check whether we violate the tickets reservation.
2254  *      3. While writing to this iclog
2255  *          A. Reserve as much space in this iclog as can get
2256  *          B. If this is first write, save away start lsn
2257  *          C. While writing this region:
2258  *              1. If first write of transaction, write start record
2259  *              2. Write log operation header (header per region)
2260  *              3. Find out if we can fit entire region into this iclog
2261  *              4. Potentially, verify destination memcpy ptr
2262  *              5. Memcpy (partial) region
2263  *              6. If partial copy, release iclog; otherwise, continue
2264  *                      copying more regions into current iclog
2265  *      4. Mark want sync bit (in simulation mode)
2266  *      5. Release iclog for potential flush to on-disk log.
2267  *
2268  * ERRORS:
2269  * 1.   Panic if reservation is overrun.  This should never happen since
2270  *      reservation amounts are generated internal to the filesystem.
2271  * NOTES:
2272  * 1. Tickets are single threaded data structures.
2273  * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2274  *      syncing routine.  When a single log_write region needs to span
2275  *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2276  *      on all log operation writes which don't contain the end of the
2277  *      region.  The XLOG_END_TRANS bit is used for the in-core log
2278  *      operation which contains the end of the continued log_write region.
2279  * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2280  *      we don't really know exactly how much space will be used.  As a result,
2281  *      we don't update ic_offset until the end when we know exactly how many
2282  *      bytes have been written out.
2283  */
2284 int
2285 xlog_write(
2286         struct xlog             *log,
2287         struct xfs_log_vec      *log_vector,
2288         struct xlog_ticket      *ticket,
2289         xfs_lsn_t               *start_lsn,
2290         struct xlog_in_core     **commit_iclog,
2291         uint                    flags)
2292 {
2293         struct xlog_in_core     *iclog = NULL;
2294         struct xfs_log_iovec    *vecp;
2295         struct xfs_log_vec      *lv;
2296         int                     len;
2297         int                     index;
2298         int                     partial_copy = 0;
2299         int                     partial_copy_len = 0;
2300         int                     contwr = 0;
2301         int                     record_cnt = 0;
2302         int                     data_cnt = 0;
2303         int                     error;
2304
2305         *start_lsn = 0;
2306
2307         len = xlog_write_calc_vec_length(ticket, log_vector);
2308
2309         /*
2310          * Region headers and bytes are already accounted for.
2311          * We only need to take into account start records and
2312          * split regions in this function.
2313          */
2314         if (ticket->t_flags & XLOG_TIC_INITED)
2315                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2316
2317         /*
2318          * Commit record headers need to be accounted for. These
2319          * come in as separate writes so are easy to detect.
2320          */
2321         if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
2322                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2323
2324         if (ticket->t_curr_res < 0)
2325                 xlog_print_tic_res(log->l_mp, ticket);
2326
2327         index = 0;
2328         lv = log_vector;
2329         vecp = lv->lv_iovecp;
2330         while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2331                 void            *ptr;
2332                 int             log_offset;
2333
2334                 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2335                                                    &contwr, &log_offset);
2336                 if (error)
2337                         return error;
2338
2339                 ASSERT(log_offset <= iclog->ic_size - 1);
2340                 ptr = iclog->ic_datap + log_offset;
2341
2342                 /* start_lsn is the first lsn written to. That's all we need. */
2343                 if (!*start_lsn)
2344                         *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2345
2346                 /*
2347                  * This loop writes out as many regions as can fit in the amount
2348                  * of space which was allocated by xlog_state_get_iclog_space().
2349                  */
2350                 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2351                         struct xfs_log_iovec    *reg;
2352                         struct xlog_op_header   *ophdr;
2353                         int                     start_rec_copy;
2354                         int                     copy_len;
2355                         int                     copy_off;
2356                         bool                    ordered = false;
2357
2358                         /* ordered log vectors have no regions to write */
2359                         if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
2360                                 ASSERT(lv->lv_niovecs == 0);
2361                                 ordered = true;
2362                                 goto next_lv;
2363                         }
2364
2365                         reg = &vecp[index];
2366                         ASSERT(reg->i_len % sizeof(__int32_t) == 0);
2367                         ASSERT((unsigned long)ptr % sizeof(__int32_t) == 0);
2368
2369                         start_rec_copy = xlog_write_start_rec(ptr, ticket);
2370                         if (start_rec_copy) {
2371                                 record_cnt++;
2372                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2373                                                    start_rec_copy);
2374                         }
2375
2376                         ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
2377                         if (!ophdr)
2378                                 return -EIO;
2379
2380                         xlog_write_adv_cnt(&ptr, &len, &log_offset,
2381                                            sizeof(struct xlog_op_header));
2382
2383                         len += xlog_write_setup_copy(ticket, ophdr,
2384                                                      iclog->ic_size-log_offset,
2385                                                      reg->i_len,
2386                                                      &copy_off, &copy_len,
2387                                                      &partial_copy,
2388                                                      &partial_copy_len);
2389                         xlog_verify_dest_ptr(log, ptr);
2390
2391                         /* copy region */
2392                         ASSERT(copy_len >= 0);
2393                         memcpy(ptr, reg->i_addr + copy_off, copy_len);
2394                         xlog_write_adv_cnt(&ptr, &len, &log_offset, copy_len);
2395
2396                         copy_len += start_rec_copy + sizeof(xlog_op_header_t);
2397                         record_cnt++;
2398                         data_cnt += contwr ? copy_len : 0;
2399
2400                         error = xlog_write_copy_finish(log, iclog, flags,
2401                                                        &record_cnt, &data_cnt,
2402                                                        &partial_copy,
2403                                                        &partial_copy_len,
2404                                                        log_offset,
2405                                                        commit_iclog);
2406                         if (error)
2407                                 return error;
2408
2409                         /*
2410                          * if we had a partial copy, we need to get more iclog
2411                          * space but we don't want to increment the region
2412                          * index because there is still more is this region to
2413                          * write.
2414                          *
2415                          * If we completed writing this region, and we flushed
2416                          * the iclog (indicated by resetting of the record
2417                          * count), then we also need to get more log space. If
2418                          * this was the last record, though, we are done and
2419                          * can just return.
2420                          */
2421                         if (partial_copy)
2422                                 break;
2423
2424                         if (++index == lv->lv_niovecs) {
2425 next_lv:
2426                                 lv = lv->lv_next;
2427                                 index = 0;
2428                                 if (lv)
2429                                         vecp = lv->lv_iovecp;
2430                         }
2431                         if (record_cnt == 0 && ordered == false) {
2432                                 if (!lv)
2433                                         return 0;
2434                                 break;
2435                         }
2436                 }
2437         }
2438
2439         ASSERT(len == 0);
2440
2441         xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2442         if (!commit_iclog)
2443                 return xlog_state_release_iclog(log, iclog);
2444
2445         ASSERT(flags & XLOG_COMMIT_TRANS);
2446         *commit_iclog = iclog;
2447         return 0;
2448 }
2449
2450
2451 /*****************************************************************************
2452  *
2453  *              State Machine functions
2454  *
2455  *****************************************************************************
2456  */
2457
2458 /* Clean iclogs starting from the head.  This ordering must be
2459  * maintained, so an iclog doesn't become ACTIVE beyond one that
2460  * is SYNCING.  This is also required to maintain the notion that we use
2461  * a ordered wait queue to hold off would be writers to the log when every
2462  * iclog is trying to sync to disk.
2463  *
2464  * State Change: DIRTY -> ACTIVE
2465  */
2466 STATIC void
2467 xlog_state_clean_log(
2468         struct xlog *log)
2469 {
2470         xlog_in_core_t  *iclog;
2471         int changed = 0;
2472
2473         iclog = log->l_iclog;
2474         do {
2475                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
2476                         iclog->ic_state = XLOG_STATE_ACTIVE;
2477                         iclog->ic_offset       = 0;
2478                         ASSERT(iclog->ic_callback == NULL);
2479                         /*
2480                          * If the number of ops in this iclog indicate it just
2481                          * contains the dummy transaction, we can
2482                          * change state into IDLE (the second time around).
2483                          * Otherwise we should change the state into
2484                          * NEED a dummy.
2485                          * We don't need to cover the dummy.
2486                          */
2487                         if (!changed &&
2488                            (be32_to_cpu(iclog->ic_header.h_num_logops) ==
2489                                         XLOG_COVER_OPS)) {
2490                                 changed = 1;
2491                         } else {
2492                                 /*
2493                                  * We have two dirty iclogs so start over
2494                                  * This could also be num of ops indicates
2495                                  * this is not the dummy going out.
2496                                  */
2497                                 changed = 2;
2498                         }
2499                         iclog->ic_header.h_num_logops = 0;
2500                         memset(iclog->ic_header.h_cycle_data, 0,
2501                               sizeof(iclog->ic_header.h_cycle_data));
2502                         iclog->ic_header.h_lsn = 0;
2503                 } else if (iclog->ic_state == XLOG_STATE_ACTIVE)
2504                         /* do nothing */;
2505                 else
2506                         break;  /* stop cleaning */
2507                 iclog = iclog->ic_next;
2508         } while (iclog != log->l_iclog);
2509
2510         /* log is locked when we are called */
2511         /*
2512          * Change state for the dummy log recording.
2513          * We usually go to NEED. But we go to NEED2 if the changed indicates
2514          * we are done writing the dummy record.
2515          * If we are done with the second dummy recored (DONE2), then
2516          * we go to IDLE.
2517          */
2518         if (changed) {
2519                 switch (log->l_covered_state) {
2520                 case XLOG_STATE_COVER_IDLE:
2521                 case XLOG_STATE_COVER_NEED:
2522                 case XLOG_STATE_COVER_NEED2:
2523                         log->l_covered_state = XLOG_STATE_COVER_NEED;
2524                         break;
2525
2526                 case XLOG_STATE_COVER_DONE:
2527                         if (changed == 1)
2528                                 log->l_covered_state = XLOG_STATE_COVER_NEED2;
2529                         else
2530                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2531                         break;
2532
2533                 case XLOG_STATE_COVER_DONE2:
2534                         if (changed == 1)
2535                                 log->l_covered_state = XLOG_STATE_COVER_IDLE;
2536                         else
2537                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2538                         break;
2539
2540                 default:
2541                         ASSERT(0);
2542                 }
2543         }
2544 }       /* xlog_state_clean_log */
2545
2546 STATIC xfs_lsn_t
2547 xlog_get_lowest_lsn(
2548         struct xlog     *log)
2549 {
2550         xlog_in_core_t  *lsn_log;
2551         xfs_lsn_t       lowest_lsn, lsn;
2552
2553         lsn_log = log->l_iclog;
2554         lowest_lsn = 0;
2555         do {
2556             if (!(lsn_log->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY))) {
2557                 lsn = be64_to_cpu(lsn_log->ic_header.h_lsn);
2558                 if ((lsn && !lowest_lsn) ||
2559                     (XFS_LSN_CMP(lsn, lowest_lsn) < 0)) {
2560                         lowest_lsn = lsn;
2561                 }
2562             }
2563             lsn_log = lsn_log->ic_next;
2564         } while (lsn_log != log->l_iclog);
2565         return lowest_lsn;
2566 }
2567
2568
2569 STATIC void
2570 xlog_state_do_callback(
2571         struct xlog             *log,
2572         int                     aborted,
2573         struct xlog_in_core     *ciclog)
2574 {
2575         xlog_in_core_t     *iclog;
2576         xlog_in_core_t     *first_iclog;        /* used to know when we've
2577                                                  * processed all iclogs once */
2578         xfs_log_callback_t *cb, *cb_next;
2579         int                flushcnt = 0;
2580         xfs_lsn_t          lowest_lsn;
2581         int                ioerrors;    /* counter: iclogs with errors */
2582         int                loopdidcallbacks; /* flag: inner loop did callbacks*/
2583         int                funcdidcallbacks; /* flag: function did callbacks */
2584         int                repeats;     /* for issuing console warnings if
2585                                          * looping too many times */
2586         int                wake = 0;
2587
2588         spin_lock(&log->l_icloglock);
2589         first_iclog = iclog = log->l_iclog;
2590         ioerrors = 0;
2591         funcdidcallbacks = 0;
2592         repeats = 0;
2593
2594         do {
2595                 /*
2596                  * Scan all iclogs starting with the one pointed to by the
2597                  * log.  Reset this starting point each time the log is
2598                  * unlocked (during callbacks).
2599                  *
2600                  * Keep looping through iclogs until one full pass is made
2601                  * without running any callbacks.
2602                  */
2603                 first_iclog = log->l_iclog;
2604                 iclog = log->l_iclog;
2605                 loopdidcallbacks = 0;
2606                 repeats++;
2607
2608                 do {
2609
2610                         /* skip all iclogs in the ACTIVE & DIRTY states */
2611                         if (iclog->ic_state &
2612                             (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
2613                                 iclog = iclog->ic_next;
2614                                 continue;
2615                         }
2616
2617                         /*
2618                          * Between marking a filesystem SHUTDOWN and stopping
2619                          * the log, we do flush all iclogs to disk (if there
2620                          * wasn't a log I/O error). So, we do want things to
2621                          * go smoothly in case of just a SHUTDOWN  w/o a
2622                          * LOG_IO_ERROR.
2623                          */
2624                         if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
2625                                 /*
2626                                  * Can only perform callbacks in order.  Since
2627                                  * this iclog is not in the DONE_SYNC/
2628                                  * DO_CALLBACK state, we skip the rest and
2629                                  * just try to clean up.  If we set our iclog
2630                                  * to DO_CALLBACK, we will not process it when
2631                                  * we retry since a previous iclog is in the
2632                                  * CALLBACK and the state cannot change since
2633                                  * we are holding the l_icloglock.
2634                                  */
2635                                 if (!(iclog->ic_state &
2636                                         (XLOG_STATE_DONE_SYNC |
2637                                                  XLOG_STATE_DO_CALLBACK))) {
2638                                         if (ciclog && (ciclog->ic_state ==
2639                                                         XLOG_STATE_DONE_SYNC)) {
2640                                                 ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
2641                                         }
2642                                         break;
2643                                 }
2644                                 /*
2645                                  * We now have an iclog that is in either the
2646                                  * DO_CALLBACK or DONE_SYNC states. The other
2647                                  * states (WANT_SYNC, SYNCING, or CALLBACK were
2648                                  * caught by the above if and are going to
2649                                  * clean (i.e. we aren't doing their callbacks)
2650                                  * see the above if.
2651                                  */
2652
2653                                 /*
2654                                  * We will do one more check here to see if we
2655                                  * have chased our tail around.
2656                                  */
2657
2658                                 lowest_lsn = xlog_get_lowest_lsn(log);
2659                                 if (lowest_lsn &&
2660                                     XFS_LSN_CMP(lowest_lsn,
2661                                                 be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
2662                                         iclog = iclog->ic_next;
2663                                         continue; /* Leave this iclog for
2664                                                    * another thread */
2665                                 }
2666
2667                                 iclog->ic_state = XLOG_STATE_CALLBACK;
2668
2669
2670                                 /*
2671                                  * Completion of a iclog IO does not imply that
2672                                  * a transaction has completed, as transactions
2673                                  * can be large enough to span many iclogs. We
2674                                  * cannot change the tail of the log half way
2675                                  * through a transaction as this may be the only
2676                                  * transaction in the log and moving th etail to
2677                                  * point to the middle of it will prevent
2678                                  * recovery from finding the start of the
2679                                  * transaction. Hence we should only update the
2680                                  * last_sync_lsn if this iclog contains
2681                                  * transaction completion callbacks on it.
2682                                  *
2683                                  * We have to do this before we drop the
2684                                  * icloglock to ensure we are the only one that
2685                                  * can update it.
2686                                  */
2687                                 ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2688                                         be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
2689                                 if (iclog->ic_callback)
2690                                         atomic64_set(&log->l_last_sync_lsn,
2691                                                 be64_to_cpu(iclog->ic_header.h_lsn));
2692
2693                         } else
2694                                 ioerrors++;
2695
2696                         spin_unlock(&log->l_icloglock);
2697
2698                         /*
2699                          * Keep processing entries in the callback list until
2700                          * we come around and it is empty.  We need to
2701                          * atomically see that the list is empty and change the
2702                          * state to DIRTY so that we don't miss any more
2703                          * callbacks being added.
2704                          */
2705                         spin_lock(&iclog->ic_callback_lock);
2706                         cb = iclog->ic_callback;
2707                         while (cb) {
2708                                 iclog->ic_callback_tail = &(iclog->ic_callback);
2709                                 iclog->ic_callback = NULL;
2710                                 spin_unlock(&iclog->ic_callback_lock);
2711
2712                                 /* perform callbacks in the order given */
2713                                 for (; cb; cb = cb_next) {
2714                                         cb_next = cb->cb_next;
2715                                         cb->cb_func(cb->cb_arg, aborted);
2716                                 }
2717                                 spin_lock(&iclog->ic_callback_lock);
2718                                 cb = iclog->ic_callback;
2719                         }
2720
2721                         loopdidcallbacks++;
2722                         funcdidcallbacks++;
2723
2724                         spin_lock(&log->l_icloglock);
2725                         ASSERT(iclog->ic_callback == NULL);
2726                         spin_unlock(&iclog->ic_callback_lock);
2727                         if (!(iclog->ic_state & XLOG_STATE_IOERROR))
2728                                 iclog->ic_state = XLOG_STATE_DIRTY;
2729
2730                         /*
2731                          * Transition from DIRTY to ACTIVE if applicable.
2732                          * NOP if STATE_IOERROR.
2733                          */
2734                         xlog_state_clean_log(log);
2735
2736                         /* wake up threads waiting in xfs_log_force() */
2737                         wake_up_all(&iclog->ic_force_wait);
2738
2739                         iclog = iclog->ic_next;
2740                 } while (first_iclog != iclog);
2741
2742                 if (repeats > 5000) {
2743                         flushcnt += repeats;
2744                         repeats = 0;
2745                         xfs_warn(log->l_mp,
2746                                 "%s: possible infinite loop (%d iterations)",
2747                                 __func__, flushcnt);
2748                 }
2749         } while (!ioerrors && loopdidcallbacks);
2750
2751         /*
2752          * make one last gasp attempt to see if iclogs are being left in
2753          * limbo..
2754          */
2755 #ifdef DEBUG
2756         if (funcdidcallbacks) {
2757                 first_iclog = iclog = log->l_iclog;
2758                 do {
2759                         ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
2760                         /*
2761                          * Terminate the loop if iclogs are found in states
2762                          * which will cause other threads to clean up iclogs.
2763                          *
2764                          * SYNCING - i/o completion will go through logs
2765                          * DONE_SYNC - interrupt thread should be waiting for
2766                          *              l_icloglock
2767                          * IOERROR - give up hope all ye who enter here
2768                          */
2769                         if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2770                             iclog->ic_state == XLOG_STATE_SYNCING ||
2771                             iclog->ic_state == XLOG_STATE_DONE_SYNC ||
2772                             iclog->ic_state == XLOG_STATE_IOERROR )
2773                                 break;
2774                         iclog = iclog->ic_next;
2775                 } while (first_iclog != iclog);
2776         }
2777 #endif
2778
2779         if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
2780                 wake = 1;
2781         spin_unlock(&log->l_icloglock);
2782
2783         if (wake)
2784                 wake_up_all(&log->l_flush_wait);
2785 }
2786
2787
2788 /*
2789  * Finish transitioning this iclog to the dirty state.
2790  *
2791  * Make sure that we completely execute this routine only when this is
2792  * the last call to the iclog.  There is a good chance that iclog flushes,
2793  * when we reach the end of the physical log, get turned into 2 separate
2794  * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2795  * routine.  By using the reference count bwritecnt, we guarantee that only
2796  * the second completion goes through.
2797  *
2798  * Callbacks could take time, so they are done outside the scope of the
2799  * global state machine log lock.
2800  */
2801 STATIC void
2802 xlog_state_done_syncing(
2803         xlog_in_core_t  *iclog,
2804         int             aborted)
2805 {
2806         struct xlog        *log = iclog->ic_log;
2807
2808         spin_lock(&log->l_icloglock);
2809
2810         ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
2811                iclog->ic_state == XLOG_STATE_IOERROR);
2812         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2813         ASSERT(iclog->ic_bwritecnt == 1 || iclog->ic_bwritecnt == 2);
2814
2815
2816         /*
2817          * If we got an error, either on the first buffer, or in the case of
2818          * split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
2819          * and none should ever be attempted to be written to disk
2820          * again.
2821          */
2822         if (iclog->ic_state != XLOG_STATE_IOERROR) {
2823                 if (--iclog->ic_bwritecnt == 1) {
2824                         spin_unlock(&log->l_icloglock);
2825                         return;
2826                 }
2827                 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2828         }
2829
2830         /*
2831          * Someone could be sleeping prior to writing out the next
2832          * iclog buffer, we wake them all, one will get to do the
2833          * I/O, the others get to wait for the result.
2834          */
2835         wake_up_all(&iclog->ic_write_wait);
2836         spin_unlock(&log->l_icloglock);
2837         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
2838 }       /* xlog_state_done_syncing */
2839
2840
2841 /*
2842  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2843  * sleep.  We wait on the flush queue on the head iclog as that should be
2844  * the first iclog to complete flushing. Hence if all iclogs are syncing,
2845  * we will wait here and all new writes will sleep until a sync completes.
2846  *
2847  * The in-core logs are used in a circular fashion. They are not used
2848  * out-of-order even when an iclog past the head is free.
2849  *
2850  * return:
2851  *      * log_offset where xlog_write() can start writing into the in-core
2852  *              log's data space.
2853  *      * in-core log pointer to which xlog_write() should write.
2854  *      * boolean indicating this is a continued write to an in-core log.
2855  *              If this is the last write, then the in-core log's offset field
2856  *              needs to be incremented, depending on the amount of data which
2857  *              is copied.
2858  */
2859 STATIC int
2860 xlog_state_get_iclog_space(
2861         struct xlog             *log,
2862         int                     len,
2863         struct xlog_in_core     **iclogp,
2864         struct xlog_ticket      *ticket,
2865         int                     *continued_write,
2866         int                     *logoffsetp)
2867 {
2868         int               log_offset;
2869         xlog_rec_header_t *head;
2870         xlog_in_core_t    *iclog;
2871         int               error;
2872
2873 restart:
2874         spin_lock(&log->l_icloglock);
2875         if (XLOG_FORCED_SHUTDOWN(log)) {
2876                 spin_unlock(&log->l_icloglock);
2877                 return -EIO;
2878         }
2879
2880         iclog = log->l_iclog;
2881         if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2882                 XFS_STATS_INC(xs_log_noiclogs);
2883
2884                 /* Wait for log writes to have flushed */
2885                 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2886                 goto restart;
2887         }
2888
2889         head = &iclog->ic_header;
2890
2891         atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2892         log_offset = iclog->ic_offset;
2893
2894         /* On the 1st write to an iclog, figure out lsn.  This works
2895          * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2896          * committing to.  If the offset is set, that's how many blocks
2897          * must be written.
2898          */
2899         if (log_offset == 0) {
2900                 ticket->t_curr_res -= log->l_iclog_hsize;
2901                 xlog_tic_add_region(ticket,
2902                                     log->l_iclog_hsize,
2903                                     XLOG_REG_TYPE_LRHEADER);
2904                 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2905                 head->h_lsn = cpu_to_be64(
2906                         xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2907                 ASSERT(log->l_curr_block >= 0);
2908         }
2909
2910         /* If there is enough room to write everything, then do it.  Otherwise,
2911          * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2912          * bit is on, so this will get flushed out.  Don't update ic_offset
2913          * until you know exactly how many bytes get copied.  Therefore, wait
2914          * until later to update ic_offset.
2915          *
2916          * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2917          * can fit into remaining data section.
2918          */
2919         if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2920                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2921
2922                 /*
2923                  * If I'm the only one writing to this iclog, sync it to disk.
2924                  * We need to do an atomic compare and decrement here to avoid
2925                  * racing with concurrent atomic_dec_and_lock() calls in
2926                  * xlog_state_release_iclog() when there is more than one
2927                  * reference to the iclog.
2928                  */
2929                 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
2930                         /* we are the only one */
2931                         spin_unlock(&log->l_icloglock);
2932                         error = xlog_state_release_iclog(log, iclog);
2933                         if (error)
2934                                 return error;
2935                 } else {
2936                         spin_unlock(&log->l_icloglock);
2937                 }
2938                 goto restart;
2939         }
2940
2941         /* Do we have enough room to write the full amount in the remainder
2942          * of this iclog?  Or must we continue a write on the next iclog and
2943          * mark this iclog as completely taken?  In the case where we switch
2944          * iclogs (to mark it taken), this particular iclog will release/sync
2945          * to disk in xlog_write().
2946          */
2947         if (len <= iclog->ic_size - iclog->ic_offset) {
2948                 *continued_write = 0;
2949                 iclog->ic_offset += len;
2950         } else {
2951                 *continued_write = 1;
2952                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2953         }
2954         *iclogp = iclog;
2955
2956         ASSERT(iclog->ic_offset <= iclog->ic_size);
2957         spin_unlock(&log->l_icloglock);
2958
2959         *logoffsetp = log_offset;
2960         return 0;
2961 }       /* xlog_state_get_iclog_space */
2962
2963 /* The first cnt-1 times through here we don't need to
2964  * move the grant write head because the permanent
2965  * reservation has reserved cnt times the unit amount.
2966  * Release part of current permanent unit reservation and
2967  * reset current reservation to be one units worth.  Also
2968  * move grant reservation head forward.
2969  */
2970 STATIC void
2971 xlog_regrant_reserve_log_space(
2972         struct xlog             *log,
2973         struct xlog_ticket      *ticket)
2974 {
2975         trace_xfs_log_regrant_reserve_enter(log, ticket);
2976
2977         if (ticket->t_cnt > 0)
2978                 ticket->t_cnt--;
2979
2980         xlog_grant_sub_space(log, &log->l_reserve_head.grant,
2981                                         ticket->t_curr_res);
2982         xlog_grant_sub_space(log, &log->l_write_head.grant,
2983                                         ticket->t_curr_res);
2984         ticket->t_curr_res = ticket->t_unit_res;
2985         xlog_tic_reset_res(ticket);
2986
2987         trace_xfs_log_regrant_reserve_sub(log, ticket);
2988
2989         /* just return if we still have some of the pre-reserved space */
2990         if (ticket->t_cnt > 0)
2991                 return;
2992
2993         xlog_grant_add_space(log, &log->l_reserve_head.grant,
2994                                         ticket->t_unit_res);
2995
2996         trace_xfs_log_regrant_reserve_exit(log, ticket);
2997
2998         ticket->t_curr_res = ticket->t_unit_res;
2999         xlog_tic_reset_res(ticket);
3000 }       /* xlog_regrant_reserve_log_space */
3001
3002
3003 /*
3004  * Give back the space left from a reservation.
3005  *
3006  * All the information we need to make a correct determination of space left
3007  * is present.  For non-permanent reservations, things are quite easy.  The
3008  * count should have been decremented to zero.  We only need to deal with the
3009  * space remaining in the current reservation part of the ticket.  If the
3010  * ticket contains a permanent reservation, there may be left over space which
3011  * needs to be released.  A count of N means that N-1 refills of the current
3012  * reservation can be done before we need to ask for more space.  The first
3013  * one goes to fill up the first current reservation.  Once we run out of
3014  * space, the count will stay at zero and the only space remaining will be
3015  * in the current reservation field.
3016  */
3017 STATIC void
3018 xlog_ungrant_log_space(
3019         struct xlog             *log,
3020         struct xlog_ticket      *ticket)
3021 {
3022         int     bytes;
3023
3024         if (ticket->t_cnt > 0)
3025                 ticket->t_cnt--;
3026
3027         trace_xfs_log_ungrant_enter(log, ticket);
3028         trace_xfs_log_ungrant_sub(log, ticket);
3029
3030         /*
3031          * If this is a permanent reservation ticket, we may be able to free
3032          * up more space based on the remaining count.
3033          */
3034         bytes = ticket->t_curr_res;
3035         if (ticket->t_cnt > 0) {
3036                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3037                 bytes += ticket->t_unit_res*ticket->t_cnt;
3038         }
3039
3040         xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3041         xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3042
3043         trace_xfs_log_ungrant_exit(log, ticket);
3044
3045         xfs_log_space_wake(log->l_mp);
3046 }
3047
3048 /*
3049  * Flush iclog to disk if this is the last reference to the given iclog and
3050  * the WANT_SYNC bit is set.
3051  *
3052  * When this function is entered, the iclog is not necessarily in the
3053  * WANT_SYNC state.  It may be sitting around waiting to get filled.
3054  *
3055  *
3056  */
3057 STATIC int
3058 xlog_state_release_iclog(
3059         struct xlog             *log,
3060         struct xlog_in_core     *iclog)
3061 {
3062         int             sync = 0;       /* do we sync? */
3063
3064         if (iclog->ic_state & XLOG_STATE_IOERROR)
3065                 return -EIO;
3066
3067         ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
3068         if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
3069                 return 0;
3070
3071         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3072                 spin_unlock(&log->l_icloglock);
3073                 return -EIO;
3074         }
3075         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
3076                iclog->ic_state == XLOG_STATE_WANT_SYNC);
3077
3078         if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
3079                 /* update tail before writing to iclog */
3080                 xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp);
3081                 sync++;
3082                 iclog->ic_state = XLOG_STATE_SYNCING;
3083                 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
3084                 xlog_verify_tail_lsn(log, iclog, tail_lsn);
3085                 /* cycle incremented when incrementing curr_block */
3086         }
3087         spin_unlock(&log->l_icloglock);
3088
3089         /*
3090          * We let the log lock go, so it's possible that we hit a log I/O
3091          * error or some other SHUTDOWN condition that marks the iclog
3092          * as XLOG_STATE_IOERROR before the bwrite. However, we know that
3093          * this iclog has consistent data, so we ignore IOERROR
3094          * flags after this point.
3095          */
3096         if (sync)
3097                 return xlog_sync(log, iclog);
3098         return 0;
3099 }       /* xlog_state_release_iclog */
3100
3101
3102 /*
3103  * This routine will mark the current iclog in the ring as WANT_SYNC
3104  * and move the current iclog pointer to the next iclog in the ring.
3105  * When this routine is called from xlog_state_get_iclog_space(), the
3106  * exact size of the iclog has not yet been determined.  All we know is
3107  * that every data block.  We have run out of space in this log record.
3108  */
3109 STATIC void
3110 xlog_state_switch_iclogs(
3111         struct xlog             *log,
3112         struct xlog_in_core     *iclog,
3113         int                     eventual_size)
3114 {
3115         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3116         if (!eventual_size)
3117                 eventual_size = iclog->ic_offset;
3118         iclog->ic_state = XLOG_STATE_WANT_SYNC;
3119         iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3120         log->l_prev_block = log->l_curr_block;
3121         log->l_prev_cycle = log->l_curr_cycle;
3122
3123         /* roll log?: ic_offset changed later */
3124         log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3125
3126         /* Round up to next log-sunit */
3127         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3128             log->l_mp->m_sb.sb_logsunit > 1) {
3129                 __uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
3130                 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3131         }
3132
3133         if (log->l_curr_block >= log->l_logBBsize) {
3134                 log->l_curr_cycle++;
3135                 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3136                         log->l_curr_cycle++;
3137                 log->l_curr_block -= log->l_logBBsize;
3138                 ASSERT(log->l_curr_block >= 0);
3139         }
3140         ASSERT(iclog == log->l_iclog);
3141         log->l_iclog = iclog->ic_next;
3142 }       /* xlog_state_switch_iclogs */
3143
3144 /*
3145  * Write out all data in the in-core log as of this exact moment in time.
3146  *
3147  * Data may be written to the in-core log during this call.  However,
3148  * we don't guarantee this data will be written out.  A change from past
3149  * implementation means this routine will *not* write out zero length LRs.
3150  *
3151  * Basically, we try and perform an intelligent scan of the in-core logs.
3152  * If we determine there is no flushable data, we just return.  There is no
3153  * flushable data if:
3154  *
3155  *      1. the current iclog is active and has no data; the previous iclog
3156  *              is in the active or dirty state.
3157  *      2. the current iclog is drity, and the previous iclog is in the
3158  *              active or dirty state.
3159  *
3160  * We may sleep if:
3161  *
3162  *      1. the current iclog is not in the active nor dirty state.
3163  *      2. the current iclog dirty, and the previous iclog is not in the
3164  *              active nor dirty state.
3165  *      3. the current iclog is active, and there is another thread writing
3166  *              to this particular iclog.
3167  *      4. a) the current iclog is active and has no other writers
3168  *         b) when we return from flushing out this iclog, it is still
3169  *              not in the active nor dirty state.
3170  */
3171 int
3172 _xfs_log_force(
3173         struct xfs_mount        *mp,
3174         uint                    flags,
3175         int                     *log_flushed)
3176 {
3177         struct xlog             *log = mp->m_log;
3178         struct xlog_in_core     *iclog;
3179         xfs_lsn_t               lsn;
3180
3181         XFS_STATS_INC(xs_log_force);
3182
3183         xlog_cil_force(log);
3184
3185         spin_lock(&log->l_icloglock);
3186
3187         iclog = log->l_iclog;
3188         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3189                 spin_unlock(&log->l_icloglock);
3190                 return -EIO;
3191         }
3192
3193         /* If the head iclog is not active nor dirty, we just attach
3194          * ourselves to the head and go to sleep.
3195          */
3196         if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3197             iclog->ic_state == XLOG_STATE_DIRTY) {
3198                 /*
3199                  * If the head is dirty or (active and empty), then
3200                  * we need to look at the previous iclog.  If the previous
3201                  * iclog is active or dirty we are done.  There is nothing
3202                  * to sync out.  Otherwise, we attach ourselves to the
3203                  * previous iclog and go to sleep.
3204                  */
3205                 if (iclog->ic_state == XLOG_STATE_DIRTY ||
3206                     (atomic_read(&iclog->ic_refcnt) == 0
3207                      && iclog->ic_offset == 0)) {
3208                         iclog = iclog->ic_prev;
3209                         if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3210                             iclog->ic_state == XLOG_STATE_DIRTY)
3211                                 goto no_sleep;
3212                         else
3213                                 goto maybe_sleep;
3214                 } else {
3215                         if (atomic_read(&iclog->ic_refcnt) == 0) {
3216                                 /* We are the only one with access to this
3217                                  * iclog.  Flush it out now.  There should
3218                                  * be a roundoff of zero to show that someone
3219                                  * has already taken care of the roundoff from
3220                                  * the previous sync.
3221                                  */
3222                                 atomic_inc(&iclog->ic_refcnt);
3223                                 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3224                                 xlog_state_switch_iclogs(log, iclog, 0);
3225                                 spin_unlock(&log->l_icloglock);
3226
3227                                 if (xlog_state_release_iclog(log, iclog))
3228                                         return -EIO;
3229
3230                                 if (log_flushed)
3231                                         *log_flushed = 1;
3232                                 spin_lock(&log->l_icloglock);
3233                                 if (be64_to_cpu(iclog->ic_header.h_lsn) == lsn &&
3234                                     iclog->ic_state != XLOG_STATE_DIRTY)
3235                                         goto maybe_sleep;
3236                                 else
3237                                         goto no_sleep;
3238                         } else {
3239                                 /* Someone else is writing to this iclog.
3240                                  * Use its call to flush out the data.  However,
3241                                  * the other thread may not force out this LR,
3242                                  * so we mark it WANT_SYNC.
3243                                  */
3244                                 xlog_state_switch_iclogs(log, iclog, 0);
3245                                 goto maybe_sleep;
3246                         }
3247                 }
3248         }
3249
3250         /* By the time we come around again, the iclog could've been filled
3251          * which would give it another lsn.  If we have a new lsn, just
3252          * return because the relevant data has been flushed.
3253          */
3254 maybe_sleep:
3255         if (flags & XFS_LOG_SYNC) {
3256                 /*
3257                  * We must check if we're shutting down here, before
3258                  * we wait, while we're holding the l_icloglock.
3259                  * Then we check again after waking up, in case our
3260                  * sleep was disturbed by a bad news.
3261                  */
3262                 if (iclog->ic_state & XLOG_STATE_IOERROR) {
3263                         spin_unlock(&log->l_icloglock);
3264                         return -EIO;
3265                 }
3266                 XFS_STATS_INC(xs_log_force_sleep);
3267                 xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3268                 /*
3269                  * No need to grab the log lock here since we're
3270                  * only deciding whether or not to return EIO
3271                  * and the memory read should be atomic.
3272                  */
3273                 if (iclog->ic_state & XLOG_STATE_IOERROR)
3274                         return -EIO;
3275                 if (log_flushed)
3276                         *log_flushed = 1;
3277         } else {
3278
3279 no_sleep:
3280                 spin_unlock(&log->l_icloglock);
3281         }
3282         return 0;
3283 }
3284
3285 /*
3286  * Wrapper for _xfs_log_force(), to be used when caller doesn't care
3287  * about errors or whether the log was flushed or not. This is the normal
3288  * interface to use when trying to unpin items or move the log forward.
3289  */
3290 void
3291 xfs_log_force(
3292         xfs_mount_t     *mp,
3293         uint            flags)
3294 {
3295         int     error;
3296
3297         trace_xfs_log_force(mp, 0);
3298         error = _xfs_log_force(mp, flags, NULL);
3299         if (error)
3300                 xfs_warn(mp, "%s: error %d returned.", __func__, error);
3301 }
3302
3303 /*
3304  * Force the in-core log to disk for a specific LSN.
3305  *
3306  * Find in-core log with lsn.
3307  *      If it is in the DIRTY state, just return.
3308  *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3309  *              state and go to sleep or return.
3310  *      If it is in any other state, go to sleep or return.
3311  *
3312  * Synchronous forces are implemented with a signal variable. All callers
3313  * to force a given lsn to disk will wait on a the sv attached to the
3314  * specific in-core log.  When given in-core log finally completes its
3315  * write to disk, that thread will wake up all threads waiting on the
3316  * sv.
3317  */
3318 int
3319 _xfs_log_force_lsn(
3320         struct xfs_mount        *mp,
3321         xfs_lsn_t               lsn,
3322         uint                    flags,
3323         int                     *log_flushed)
3324 {
3325         struct xlog             *log = mp->m_log;
3326         struct xlog_in_core     *iclog;
3327         int                     already_slept = 0;
3328
3329         ASSERT(lsn != 0);
3330
3331         XFS_STATS_INC(xs_log_force);
3332
3333         lsn = xlog_cil_force_lsn(log, lsn);
3334         if (lsn == NULLCOMMITLSN)
3335                 return 0;
3336
3337 try_again:
3338         spin_lock(&log->l_icloglock);
3339         iclog = log->l_iclog;
3340         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3341                 spin_unlock(&log->l_icloglock);
3342                 return -EIO;
3343         }
3344
3345         do {
3346                 if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3347                         iclog = iclog->ic_next;
3348                         continue;
3349                 }
3350
3351                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
3352                         spin_unlock(&log->l_icloglock);
3353                         return 0;
3354                 }
3355
3356                 if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3357                         /*
3358                          * We sleep here if we haven't already slept (e.g.
3359                          * this is the first time we've looked at the correct
3360                          * iclog buf) and the buffer before us is going to
3361                          * be sync'ed. The reason for this is that if we
3362                          * are doing sync transactions here, by waiting for
3363                          * the previous I/O to complete, we can allow a few
3364                          * more transactions into this iclog before we close
3365                          * it down.
3366                          *
3367                          * Otherwise, we mark the buffer WANT_SYNC, and bump
3368                          * up the refcnt so we can release the log (which
3369                          * drops the ref count).  The state switch keeps new
3370                          * transaction commits from using this buffer.  When
3371                          * the current commits finish writing into the buffer,
3372                          * the refcount will drop to zero and the buffer will
3373                          * go out then.
3374                          */
3375                         if (!already_slept &&
3376                             (iclog->ic_prev->ic_state &
3377                              (XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
3378                                 ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
3379
3380                                 XFS_STATS_INC(xs_log_force_sleep);
3381
3382                                 xlog_wait(&iclog->ic_prev->ic_write_wait,
3383                                                         &log->l_icloglock);
3384                                 if (log_flushed)
3385                                         *log_flushed = 1;
3386                                 already_slept = 1;
3387                                 goto try_again;
3388                         }
3389                         atomic_inc(&iclog->ic_refcnt);
3390                         xlog_state_switch_iclogs(log, iclog, 0);
3391                         spin_unlock(&log->l_icloglock);
3392                         if (xlog_state_release_iclog(log, iclog))
3393                                 return -EIO;
3394                         if (log_flushed)
3395                                 *log_flushed = 1;
3396                         spin_lock(&log->l_icloglock);
3397                 }
3398
3399                 if ((flags & XFS_LOG_SYNC) && /* sleep */
3400                     !(iclog->ic_state &
3401                       (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))) {
3402                         /*
3403                          * Don't wait on completion if we know that we've
3404                          * gotten a log write error.
3405                          */
3406                         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3407                                 spin_unlock(&log->l_icloglock);
3408                                 return -EIO;
3409                         }
3410                         XFS_STATS_INC(xs_log_force_sleep);
3411                         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3412                         /*
3413                          * No need to grab the log lock here since we're
3414                          * only deciding whether or not to return EIO
3415                          * and the memory read should be atomic.
3416                          */
3417                         if (iclog->ic_state & XLOG_STATE_IOERROR)
3418                                 return -EIO;
3419
3420                         if (log_flushed)
3421                                 *log_flushed = 1;
3422                 } else {                /* just return */
3423                         spin_unlock(&log->l_icloglock);
3424                 }
3425
3426                 return 0;
3427         } while (iclog != log->l_iclog);
3428
3429         spin_unlock(&log->l_icloglock);
3430         return 0;
3431 }
3432
3433 /*
3434  * Wrapper for _xfs_log_force_lsn(), to be used when caller doesn't care
3435  * about errors or whether the log was flushed or not. This is the normal
3436  * interface to use when trying to unpin items or move the log forward.
3437  */
3438 void
3439 xfs_log_force_lsn(
3440         xfs_mount_t     *mp,
3441         xfs_lsn_t       lsn,
3442         uint            flags)
3443 {
3444         int     error;
3445
3446         trace_xfs_log_force(mp, lsn);
3447         error = _xfs_log_force_lsn(mp, lsn, flags, NULL);
3448         if (error)
3449                 xfs_warn(mp, "%s: error %d returned.", __func__, error);
3450 }
3451
3452 /*
3453  * Called when we want to mark the current iclog as being ready to sync to
3454  * disk.
3455  */
3456 STATIC void
3457 xlog_state_want_sync(
3458         struct xlog             *log,
3459         struct xlog_in_core     *iclog)
3460 {
3461         assert_spin_locked(&log->l_icloglock);
3462
3463         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3464                 xlog_state_switch_iclogs(log, iclog, 0);
3465         } else {
3466                 ASSERT(iclog->ic_state &
3467                         (XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
3468         }
3469 }
3470
3471
3472 /*****************************************************************************
3473  *
3474  *              TICKET functions
3475  *
3476  *****************************************************************************
3477  */
3478
3479 /*
3480  * Free a used ticket when its refcount falls to zero.
3481  */
3482 void
3483 xfs_log_ticket_put(
3484         xlog_ticket_t   *ticket)
3485 {
3486         ASSERT(atomic_read(&ticket->t_ref) > 0);
3487         if (atomic_dec_and_test(&ticket->t_ref))
3488                 kmem_zone_free(xfs_log_ticket_zone, ticket);
3489 }
3490
3491 xlog_ticket_t *
3492 xfs_log_ticket_get(
3493         xlog_ticket_t   *ticket)
3494 {
3495         ASSERT(atomic_read(&ticket->t_ref) > 0);
3496         atomic_inc(&ticket->t_ref);
3497         return ticket;
3498 }
3499
3500 /*
3501  * Figure out the total log space unit (in bytes) that would be
3502  * required for a log ticket.
3503  */
3504 int
3505 xfs_log_calc_unit_res(
3506         struct xfs_mount        *mp,
3507         int                     unit_bytes)
3508 {
3509         struct xlog             *log = mp->m_log;
3510         int                     iclog_space;
3511         uint                    num_headers;
3512
3513         /*
3514          * Permanent reservations have up to 'cnt'-1 active log operations
3515          * in the log.  A unit in this case is the amount of space for one
3516          * of these log operations.  Normal reservations have a cnt of 1
3517          * and their unit amount is the total amount of space required.
3518          *
3519          * The following lines of code account for non-transaction data
3520          * which occupy space in the on-disk log.
3521          *
3522          * Normal form of a transaction is:
3523          * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3524          * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3525          *
3526          * We need to account for all the leadup data and trailer data
3527          * around the transaction data.
3528          * And then we need to account for the worst case in terms of using
3529          * more space.
3530          * The worst case will happen if:
3531          * - the placement of the transaction happens to be such that the
3532          *   roundoff is at its maximum
3533          * - the transaction data is synced before the commit record is synced
3534          *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3535          *   Therefore the commit record is in its own Log Record.
3536          *   This can happen as the commit record is called with its
3537          *   own region to xlog_write().
3538          *   This then means that in the worst case, roundoff can happen for
3539          *   the commit-rec as well.
3540          *   The commit-rec is smaller than padding in this scenario and so it is
3541          *   not added separately.
3542          */
3543
3544         /* for trans header */
3545         unit_bytes += sizeof(xlog_op_header_t);
3546         unit_bytes += sizeof(xfs_trans_header_t);
3547
3548         /* for start-rec */
3549         unit_bytes += sizeof(xlog_op_header_t);
3550
3551         /*
3552          * for LR headers - the space for data in an iclog is the size minus
3553          * the space used for the headers. If we use the iclog size, then we
3554          * undercalculate the number of headers required.
3555          *
3556          * Furthermore - the addition of op headers for split-recs might
3557          * increase the space required enough to require more log and op
3558          * headers, so take that into account too.
3559          *
3560          * IMPORTANT: This reservation makes the assumption that if this
3561          * transaction is the first in an iclog and hence has the LR headers
3562          * accounted to it, then the remaining space in the iclog is
3563          * exclusively for this transaction.  i.e. if the transaction is larger
3564          * than the iclog, it will be the only thing in that iclog.
3565          * Fundamentally, this means we must pass the entire log vector to
3566          * xlog_write to guarantee this.
3567          */
3568         iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3569         num_headers = howmany(unit_bytes, iclog_space);
3570
3571         /* for split-recs - ophdrs added when data split over LRs */
3572         unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3573
3574         /* add extra header reservations if we overrun */
3575         while (!num_headers ||
3576                howmany(unit_bytes, iclog_space) > num_headers) {
3577                 unit_bytes += sizeof(xlog_op_header_t);
3578                 num_headers++;
3579         }
3580         unit_bytes += log->l_iclog_hsize * num_headers;
3581
3582         /* for commit-rec LR header - note: padding will subsume the ophdr */
3583         unit_bytes += log->l_iclog_hsize;
3584
3585         /* for roundoff padding for transaction data and one for commit record */
3586         if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
3587                 /* log su roundoff */
3588                 unit_bytes += 2 * mp->m_sb.sb_logsunit;
3589         } else {
3590                 /* BB roundoff */
3591                 unit_bytes += 2 * BBSIZE;
3592         }
3593
3594         return unit_bytes;
3595 }
3596
3597 /*
3598  * Allocate and initialise a new log ticket.
3599  */
3600 struct xlog_ticket *
3601 xlog_ticket_alloc(
3602         struct xlog             *log,
3603         int                     unit_bytes,
3604         int                     cnt,
3605         char                    client,
3606         bool                    permanent,
3607         xfs_km_flags_t          alloc_flags)
3608 {
3609         struct xlog_ticket      *tic;
3610         int                     unit_res;
3611
3612         tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3613         if (!tic)
3614                 return NULL;
3615
3616         unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
3617
3618         atomic_set(&tic->t_ref, 1);
3619         tic->t_task             = current;
3620         INIT_LIST_HEAD(&tic->t_queue);
3621         tic->t_unit_res         = unit_res;
3622         tic->t_curr_res         = unit_res;
3623         tic->t_cnt              = cnt;
3624         tic->t_ocnt             = cnt;
3625         tic->t_tid              = prandom_u32();
3626         tic->t_clientid         = client;
3627         tic->t_flags            = XLOG_TIC_INITED;
3628         tic->t_trans_type       = 0;
3629         if (permanent)
3630                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3631
3632         xlog_tic_reset_res(tic);
3633
3634         return tic;
3635 }
3636
3637
3638 /******************************************************************************
3639  *
3640  *              Log debug routines
3641  *
3642  ******************************************************************************
3643  */
3644 #if defined(DEBUG)
3645 /*
3646  * Make sure that the destination ptr is within the valid data region of
3647  * one of the iclogs.  This uses backup pointers stored in a different
3648  * part of the log in case we trash the log structure.
3649  */
3650 void
3651 xlog_verify_dest_ptr(
3652         struct xlog     *log,
3653         char            *ptr)
3654 {
3655         int i;
3656         int good_ptr = 0;
3657
3658         for (i = 0; i < log->l_iclog_bufs; i++) {
3659                 if (ptr >= log->l_iclog_bak[i] &&
3660                     ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3661                         good_ptr++;
3662         }
3663
3664         if (!good_ptr)
3665                 xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3666 }
3667
3668 /*
3669  * Check to make sure the grant write head didn't just over lap the tail.  If
3670  * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
3671  * the cycles differ by exactly one and check the byte count.
3672  *
3673  * This check is run unlocked, so can give false positives. Rather than assert
3674  * on failures, use a warn-once flag and a panic tag to allow the admin to
3675  * determine if they want to panic the machine when such an error occurs. For
3676  * debug kernels this will have the same effect as using an assert but, unlinke
3677  * an assert, it can be turned off at runtime.
3678  */
3679 STATIC void
3680 xlog_verify_grant_tail(
3681         struct xlog     *log)
3682 {
3683         int             tail_cycle, tail_blocks;
3684         int             cycle, space;
3685
3686         xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3687         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3688         if (tail_cycle != cycle) {
3689                 if (cycle - 1 != tail_cycle &&
3690                     !(log->l_flags & XLOG_TAIL_WARN)) {
3691                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3692                                 "%s: cycle - 1 != tail_cycle", __func__);
3693                         log->l_flags |= XLOG_TAIL_WARN;
3694                 }
3695
3696                 if (space > BBTOB(tail_blocks) &&
3697                     !(log->l_flags & XLOG_TAIL_WARN)) {
3698                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3699                                 "%s: space > BBTOB(tail_blocks)", __func__);
3700                         log->l_flags |= XLOG_TAIL_WARN;
3701                 }
3702         }
3703 }
3704
3705 /* check if it will fit */
3706 STATIC void
3707 xlog_verify_tail_lsn(
3708         struct xlog             *log,
3709         struct xlog_in_core     *iclog,
3710         xfs_lsn_t               tail_lsn)
3711 {
3712     int blocks;
3713
3714     if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3715         blocks =
3716             log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3717         if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3718                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3719     } else {
3720         ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3721
3722         if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3723                 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3724
3725         blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3726         if (blocks < BTOBB(iclog->ic_offset) + 1)
3727                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3728     }
3729 }       /* xlog_verify_tail_lsn */
3730
3731 /*
3732  * Perform a number of checks on the iclog before writing to disk.
3733  *
3734  * 1. Make sure the iclogs are still circular
3735  * 2. Make sure we have a good magic number
3736  * 3. Make sure we don't have magic numbers in the data
3737  * 4. Check fields of each log operation header for:
3738  *      A. Valid client identifier
3739  *      B. tid ptr value falls in valid ptr space (user space code)
3740  *      C. Length in log record header is correct according to the
3741  *              individual operation headers within record.
3742  * 5. When a bwrite will occur within 5 blocks of the front of the physical
3743  *      log, check the preceding blocks of the physical log to make sure all
3744  *      the cycle numbers agree with the current cycle number.
3745  */
3746 STATIC void
3747 xlog_verify_iclog(
3748         struct xlog             *log,
3749         struct xlog_in_core     *iclog,
3750         int                     count,
3751         bool                    syncing)
3752 {
3753         xlog_op_header_t        *ophead;
3754         xlog_in_core_t          *icptr;
3755         xlog_in_core_2_t        *xhdr;
3756         xfs_caddr_t             ptr;
3757         xfs_caddr_t             base_ptr;
3758         __psint_t               field_offset;
3759         __uint8_t               clientid;
3760         int                     len, i, j, k, op_len;
3761         int                     idx;
3762
3763         /* check validity of iclog pointers */
3764         spin_lock(&log->l_icloglock);
3765         icptr = log->l_iclog;
3766         for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3767                 ASSERT(icptr);
3768
3769         if (icptr != log->l_iclog)
3770                 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3771         spin_unlock(&log->l_icloglock);
3772
3773         /* check log magic numbers */
3774         if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3775                 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3776
3777         ptr = (xfs_caddr_t) &iclog->ic_header;
3778         for (ptr += BBSIZE; ptr < ((xfs_caddr_t)&iclog->ic_header) + count;
3779              ptr += BBSIZE) {
3780                 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3781                         xfs_emerg(log->l_mp, "%s: unexpected magic num",
3782                                 __func__);
3783         }
3784
3785         /* check fields */
3786         len = be32_to_cpu(iclog->ic_header.h_num_logops);
3787         ptr = iclog->ic_datap;
3788         base_ptr = ptr;
3789         ophead = (xlog_op_header_t *)ptr;
3790         xhdr = iclog->ic_data;
3791         for (i = 0; i < len; i++) {
3792                 ophead = (xlog_op_header_t *)ptr;
3793
3794                 /* clientid is only 1 byte */
3795                 field_offset = (__psint_t)
3796                                ((xfs_caddr_t)&(ophead->oh_clientid) - base_ptr);
3797                 if (!syncing || (field_offset & 0x1ff)) {
3798                         clientid = ophead->oh_clientid;
3799                 } else {
3800                         idx = BTOBBT((xfs_caddr_t)&(ophead->oh_clientid) - iclog->ic_datap);
3801                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3802                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3803                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3804                                 clientid = xlog_get_client_id(
3805                                         xhdr[j].hic_xheader.xh_cycle_data[k]);
3806                         } else {
3807                                 clientid = xlog_get_client_id(
3808                                         iclog->ic_header.h_cycle_data[idx]);
3809                         }
3810                 }
3811                 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3812                         xfs_warn(log->l_mp,
3813                                 "%s: invalid clientid %d op 0x%p offset 0x%lx",
3814                                 __func__, clientid, ophead,
3815                                 (unsigned long)field_offset);
3816
3817                 /* check length */
3818                 field_offset = (__psint_t)
3819                                ((xfs_caddr_t)&(ophead->oh_len) - base_ptr);
3820                 if (!syncing || (field_offset & 0x1ff)) {
3821                         op_len = be32_to_cpu(ophead->oh_len);
3822                 } else {
3823                         idx = BTOBBT((__psint_t)&ophead->oh_len -
3824                                     (__psint_t)iclog->ic_datap);
3825                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3826                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3827                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3828                                 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3829                         } else {
3830                                 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3831                         }
3832                 }
3833                 ptr += sizeof(xlog_op_header_t) + op_len;
3834         }
3835 }       /* xlog_verify_iclog */
3836 #endif
3837
3838 /*
3839  * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3840  */
3841 STATIC int
3842 xlog_state_ioerror(
3843         struct xlog     *log)
3844 {
3845         xlog_in_core_t  *iclog, *ic;
3846
3847         iclog = log->l_iclog;
3848         if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
3849                 /*
3850                  * Mark all the incore logs IOERROR.
3851                  * From now on, no log flushes will result.
3852                  */
3853                 ic = iclog;
3854                 do {
3855                         ic->ic_state = XLOG_STATE_IOERROR;
3856                         ic = ic->ic_next;
3857                 } while (ic != iclog);
3858                 return 0;
3859         }
3860         /*
3861          * Return non-zero, if state transition has already happened.
3862          */
3863         return 1;
3864 }
3865
3866 /*
3867  * This is called from xfs_force_shutdown, when we're forcibly
3868  * shutting down the filesystem, typically because of an IO error.
3869  * Our main objectives here are to make sure that:
3870  *      a. if !logerror, flush the logs to disk. Anything modified
3871  *         after this is ignored.
3872  *      b. the filesystem gets marked 'SHUTDOWN' for all interested
3873  *         parties to find out, 'atomically'.
3874  *      c. those who're sleeping on log reservations, pinned objects and
3875  *          other resources get woken up, and be told the bad news.
3876  *      d. nothing new gets queued up after (b) and (c) are done.
3877  *
3878  * Note: for the !logerror case we need to flush the regions held in memory out
3879  * to disk first. This needs to be done before the log is marked as shutdown,
3880  * otherwise the iclog writes will fail.
3881  */
3882 int
3883 xfs_log_force_umount(
3884         struct xfs_mount        *mp,
3885         int                     logerror)
3886 {
3887         struct xlog     *log;
3888         int             retval;
3889
3890         log = mp->m_log;
3891
3892         /*
3893          * If this happens during log recovery, don't worry about
3894          * locking; the log isn't open for business yet.
3895          */
3896         if (!log ||
3897             log->l_flags & XLOG_ACTIVE_RECOVERY) {
3898                 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3899                 if (mp->m_sb_bp)
3900                         XFS_BUF_DONE(mp->m_sb_bp);
3901                 return 0;
3902         }
3903
3904         /*
3905          * Somebody could've already done the hard work for us.
3906          * No need to get locks for this.
3907          */
3908         if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
3909                 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3910                 return 1;
3911         }
3912
3913         /*
3914          * Flush all the completed transactions to disk before marking the log
3915          * being shut down. We need to do it in this order to ensure that
3916          * completed operations are safely on disk before we shut down, and that
3917          * we don't have to issue any buffer IO after the shutdown flags are set
3918          * to guarantee this.
3919          */
3920         if (!logerror)
3921                 _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
3922
3923         /*
3924          * mark the filesystem and the as in a shutdown state and wake
3925          * everybody up to tell them the bad news.
3926          */
3927         spin_lock(&log->l_icloglock);
3928         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3929         if (mp->m_sb_bp)
3930                 XFS_BUF_DONE(mp->m_sb_bp);
3931
3932         /*
3933          * Mark the log and the iclogs with IO error flags to prevent any
3934          * further log IO from being issued or completed.
3935          */
3936         log->l_flags |= XLOG_IO_ERROR;
3937         retval = xlog_state_ioerror(log);
3938         spin_unlock(&log->l_icloglock);
3939
3940         /*
3941          * We don't want anybody waiting for log reservations after this. That
3942          * means we have to wake up everybody queued up on reserveq as well as
3943          * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
3944          * we don't enqueue anything once the SHUTDOWN flag is set, and this
3945          * action is protected by the grant locks.
3946          */
3947         xlog_grant_head_wake_all(&log->l_reserve_head);
3948         xlog_grant_head_wake_all(&log->l_write_head);
3949
3950         /*
3951          * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3952          * as if the log writes were completed. The abort handling in the log
3953          * item committed callback functions will do this again under lock to
3954          * avoid races.
3955          */
3956         wake_up_all(&log->l_cilp->xc_commit_wait);
3957         xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
3958
3959 #ifdef XFSERRORDEBUG
3960         {
3961                 xlog_in_core_t  *iclog;
3962
3963                 spin_lock(&log->l_icloglock);
3964                 iclog = log->l_iclog;
3965                 do {
3966                         ASSERT(iclog->ic_callback == 0);
3967                         iclog = iclog->ic_next;
3968                 } while (iclog != log->l_iclog);
3969                 spin_unlock(&log->l_icloglock);
3970         }
3971 #endif
3972         /* return non-zero if log IOERROR transition had already happened */
3973         return retval;
3974 }
3975
3976 STATIC int
3977 xlog_iclogs_empty(
3978         struct xlog     *log)
3979 {
3980         xlog_in_core_t  *iclog;
3981
3982         iclog = log->l_iclog;
3983         do {
3984                 /* endianness does not matter here, zero is zero in
3985                  * any language.
3986                  */
3987                 if (iclog->ic_header.h_num_logops)
3988                         return 0;
3989                 iclog = iclog->ic_next;
3990         } while (iclog != log->l_iclog);
3991         return 1;
3992 }
3993