f309e1404fd6314d27446c2d9756adbc80c67976
[firefly-linux-kernel-4.4.55.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_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_log.h"
23 #include "xfs_inum.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_mount.h"
28 #include "xfs_error.h"
29 #include "xfs_log_priv.h"
30 #include "xfs_buf_item.h"
31 #include "xfs_bmap_btree.h"
32 #include "xfs_alloc_btree.h"
33 #include "xfs_ialloc_btree.h"
34 #include "xfs_log_recover.h"
35 #include "xfs_trans_priv.h"
36 #include "xfs_dinode.h"
37 #include "xfs_inode.h"
38 #include "xfs_rw.h"
39 #include "xfs_trace.h"
40
41 kmem_zone_t     *xfs_log_ticket_zone;
42
43 /* Local miscellaneous function prototypes */
44 STATIC int       xlog_commit_record(struct log *log, struct xlog_ticket *ticket,
45                                     xlog_in_core_t **, xfs_lsn_t *);
46 STATIC xlog_t *  xlog_alloc_log(xfs_mount_t     *mp,
47                                 xfs_buftarg_t   *log_target,
48                                 xfs_daddr_t     blk_offset,
49                                 int             num_bblks);
50 STATIC int       xlog_space_left(xlog_t *log, int cycle, int bytes);
51 STATIC int       xlog_sync(xlog_t *log, xlog_in_core_t *iclog);
52 STATIC void      xlog_dealloc_log(xlog_t *log);
53
54 /* local state machine functions */
55 STATIC void xlog_state_done_syncing(xlog_in_core_t *iclog, int);
56 STATIC void xlog_state_do_callback(xlog_t *log,int aborted, xlog_in_core_t *iclog);
57 STATIC int  xlog_state_get_iclog_space(xlog_t           *log,
58                                        int              len,
59                                        xlog_in_core_t   **iclog,
60                                        xlog_ticket_t    *ticket,
61                                        int              *continued_write,
62                                        int              *logoffsetp);
63 STATIC int  xlog_state_release_iclog(xlog_t             *log,
64                                      xlog_in_core_t     *iclog);
65 STATIC void xlog_state_switch_iclogs(xlog_t             *log,
66                                      xlog_in_core_t *iclog,
67                                      int                eventual_size);
68 STATIC void xlog_state_want_sync(xlog_t *log, xlog_in_core_t *iclog);
69
70 /* local functions to manipulate grant head */
71 STATIC int  xlog_grant_log_space(xlog_t         *log,
72                                  xlog_ticket_t  *xtic);
73 STATIC void xlog_grant_push_ail(xfs_mount_t     *mp,
74                                 int             need_bytes);
75 STATIC void xlog_regrant_reserve_log_space(xlog_t        *log,
76                                            xlog_ticket_t *ticket);
77 STATIC int xlog_regrant_write_log_space(xlog_t          *log,
78                                          xlog_ticket_t  *ticket);
79 STATIC void xlog_ungrant_log_space(xlog_t        *log,
80                                    xlog_ticket_t *ticket);
81
82 #if defined(DEBUG)
83 STATIC void     xlog_verify_dest_ptr(xlog_t *log, char *ptr);
84 STATIC void     xlog_verify_grant_head(xlog_t *log, int equals);
85 STATIC void     xlog_verify_iclog(xlog_t *log, xlog_in_core_t *iclog,
86                                   int count, boolean_t syncing);
87 STATIC void     xlog_verify_tail_lsn(xlog_t *log, xlog_in_core_t *iclog,
88                                      xfs_lsn_t tail_lsn);
89 #else
90 #define xlog_verify_dest_ptr(a,b)
91 #define xlog_verify_grant_head(a,b)
92 #define xlog_verify_iclog(a,b,c,d)
93 #define xlog_verify_tail_lsn(a,b,c)
94 #endif
95
96 STATIC int      xlog_iclogs_empty(xlog_t *log);
97
98
99 static void
100 xlog_ins_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
101 {
102         if (*qp) {
103                 tic->t_next         = (*qp);
104                 tic->t_prev         = (*qp)->t_prev;
105                 (*qp)->t_prev->t_next = tic;
106                 (*qp)->t_prev       = tic;
107         } else {
108                 tic->t_prev = tic->t_next = tic;
109                 *qp = tic;
110         }
111
112         tic->t_flags |= XLOG_TIC_IN_Q;
113 }
114
115 static void
116 xlog_del_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
117 {
118         if (tic == tic->t_next) {
119                 *qp = NULL;
120         } else {
121                 *qp = tic->t_next;
122                 tic->t_next->t_prev = tic->t_prev;
123                 tic->t_prev->t_next = tic->t_next;
124         }
125
126         tic->t_next = tic->t_prev = NULL;
127         tic->t_flags &= ~XLOG_TIC_IN_Q;
128 }
129
130 static void
131 xlog_grant_sub_space(struct log *log, int bytes)
132 {
133         log->l_grant_write_bytes -= bytes;
134         if (log->l_grant_write_bytes < 0) {
135                 log->l_grant_write_bytes += log->l_logsize;
136                 log->l_grant_write_cycle--;
137         }
138
139         log->l_grant_reserve_bytes -= bytes;
140         if ((log)->l_grant_reserve_bytes < 0) {
141                 log->l_grant_reserve_bytes += log->l_logsize;
142                 log->l_grant_reserve_cycle--;
143         }
144
145 }
146
147 static void
148 xlog_grant_add_space_write(struct log *log, int bytes)
149 {
150         int tmp = log->l_logsize - log->l_grant_write_bytes;
151         if (tmp > bytes)
152                 log->l_grant_write_bytes += bytes;
153         else {
154                 log->l_grant_write_cycle++;
155                 log->l_grant_write_bytes = bytes - tmp;
156         }
157 }
158
159 static void
160 xlog_grant_add_space_reserve(struct log *log, int bytes)
161 {
162         int tmp = log->l_logsize - log->l_grant_reserve_bytes;
163         if (tmp > bytes)
164                 log->l_grant_reserve_bytes += bytes;
165         else {
166                 log->l_grant_reserve_cycle++;
167                 log->l_grant_reserve_bytes = bytes - tmp;
168         }
169 }
170
171 static inline void
172 xlog_grant_add_space(struct log *log, int bytes)
173 {
174         xlog_grant_add_space_write(log, bytes);
175         xlog_grant_add_space_reserve(log, bytes);
176 }
177
178 static void
179 xlog_tic_reset_res(xlog_ticket_t *tic)
180 {
181         tic->t_res_num = 0;
182         tic->t_res_arr_sum = 0;
183         tic->t_res_num_ophdrs = 0;
184 }
185
186 static void
187 xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
188 {
189         if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
190                 /* add to overflow and start again */
191                 tic->t_res_o_flow += tic->t_res_arr_sum;
192                 tic->t_res_num = 0;
193                 tic->t_res_arr_sum = 0;
194         }
195
196         tic->t_res_arr[tic->t_res_num].r_len = len;
197         tic->t_res_arr[tic->t_res_num].r_type = type;
198         tic->t_res_arr_sum += len;
199         tic->t_res_num++;
200 }
201
202 /*
203  * NOTES:
204  *
205  *      1. currblock field gets updated at startup and after in-core logs
206  *              marked as with WANT_SYNC.
207  */
208
209 /*
210  * This routine is called when a user of a log manager ticket is done with
211  * the reservation.  If the ticket was ever used, then a commit record for
212  * the associated transaction is written out as a log operation header with
213  * no data.  The flag XLOG_TIC_INITED is set when the first write occurs with
214  * a given ticket.  If the ticket was one with a permanent reservation, then
215  * a few operations are done differently.  Permanent reservation tickets by
216  * default don't release the reservation.  They just commit the current
217  * transaction with the belief that the reservation is still needed.  A flag
218  * must be passed in before permanent reservations are actually released.
219  * When these type of tickets are not released, they need to be set into
220  * the inited state again.  By doing this, a start record will be written
221  * out when the next write occurs.
222  */
223 xfs_lsn_t
224 xfs_log_done(
225         struct xfs_mount        *mp,
226         struct xlog_ticket      *ticket,
227         struct xlog_in_core     **iclog,
228         uint                    flags)
229 {
230         struct log              *log = mp->m_log;
231         xfs_lsn_t               lsn = 0;
232
233         if (XLOG_FORCED_SHUTDOWN(log) ||
234             /*
235              * If nothing was ever written, don't write out commit record.
236              * If we get an error, just continue and give back the log ticket.
237              */
238             (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
239              (xlog_commit_record(log, ticket, iclog, &lsn)))) {
240                 lsn = (xfs_lsn_t) -1;
241                 if (ticket->t_flags & XLOG_TIC_PERM_RESERV) {
242                         flags |= XFS_LOG_REL_PERM_RESERV;
243                 }
244         }
245
246
247         if ((ticket->t_flags & XLOG_TIC_PERM_RESERV) == 0 ||
248             (flags & XFS_LOG_REL_PERM_RESERV)) {
249                 trace_xfs_log_done_nonperm(log, ticket);
250
251                 /*
252                  * Release ticket if not permanent reservation or a specific
253                  * request has been made to release a permanent reservation.
254                  */
255                 xlog_ungrant_log_space(log, ticket);
256                 xfs_log_ticket_put(ticket);
257         } else {
258                 trace_xfs_log_done_perm(log, ticket);
259
260                 xlog_regrant_reserve_log_space(log, ticket);
261                 /* If this ticket was a permanent reservation and we aren't
262                  * trying to release it, reset the inited flags; so next time
263                  * we write, a start record will be written out.
264                  */
265                 ticket->t_flags |= XLOG_TIC_INITED;
266         }
267
268         return lsn;
269 }
270
271 /*
272  * Attaches a new iclog I/O completion callback routine during
273  * transaction commit.  If the log is in error state, a non-zero
274  * return code is handed back and the caller is responsible for
275  * executing the callback at an appropriate time.
276  */
277 int
278 xfs_log_notify(
279         struct xfs_mount        *mp,
280         struct xlog_in_core     *iclog,
281         xfs_log_callback_t      *cb)
282 {
283         int     abortflg;
284
285         spin_lock(&iclog->ic_callback_lock);
286         abortflg = (iclog->ic_state & XLOG_STATE_IOERROR);
287         if (!abortflg) {
288                 ASSERT_ALWAYS((iclog->ic_state == XLOG_STATE_ACTIVE) ||
289                               (iclog->ic_state == XLOG_STATE_WANT_SYNC));
290                 cb->cb_next = NULL;
291                 *(iclog->ic_callback_tail) = cb;
292                 iclog->ic_callback_tail = &(cb->cb_next);
293         }
294         spin_unlock(&iclog->ic_callback_lock);
295         return abortflg;
296 }
297
298 int
299 xfs_log_release_iclog(
300         struct xfs_mount        *mp,
301         struct xlog_in_core     *iclog)
302 {
303         if (xlog_state_release_iclog(mp->m_log, iclog)) {
304                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
305                 return EIO;
306         }
307
308         return 0;
309 }
310
311 /*
312  *  1. Reserve an amount of on-disk log space and return a ticket corresponding
313  *      to the reservation.
314  *  2. Potentially, push buffers at tail of log to disk.
315  *
316  * Each reservation is going to reserve extra space for a log record header.
317  * When writes happen to the on-disk log, we don't subtract the length of the
318  * log record header from any reservation.  By wasting space in each
319  * reservation, we prevent over allocation problems.
320  */
321 int
322 xfs_log_reserve(
323         struct xfs_mount        *mp,
324         int                     unit_bytes,
325         int                     cnt,
326         struct xlog_ticket      **ticket,
327         __uint8_t               client,
328         uint                    flags,
329         uint                    t_type)
330 {
331         struct log              *log = mp->m_log;
332         struct xlog_ticket      *internal_ticket;
333         int                     retval = 0;
334
335         ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
336
337         if (XLOG_FORCED_SHUTDOWN(log))
338                 return XFS_ERROR(EIO);
339
340         XFS_STATS_INC(xs_try_logspace);
341
342
343         if (*ticket != NULL) {
344                 ASSERT(flags & XFS_LOG_PERM_RESERV);
345                 internal_ticket = *ticket;
346
347                 /*
348                  * this is a new transaction on the ticket, so we need to
349                  * change the transaction ID so that the next transaction has a
350                  * different TID in the log. Just add one to the existing tid
351                  * so that we can see chains of rolling transactions in the log
352                  * easily.
353                  */
354                 internal_ticket->t_tid++;
355
356                 trace_xfs_log_reserve(log, internal_ticket);
357
358                 xlog_grant_push_ail(mp, internal_ticket->t_unit_res);
359                 retval = xlog_regrant_write_log_space(log, internal_ticket);
360         } else {
361                 /* may sleep if need to allocate more tickets */
362                 internal_ticket = xlog_ticket_alloc(log, unit_bytes, cnt,
363                                                   client, flags,
364                                                   KM_SLEEP|KM_MAYFAIL);
365                 if (!internal_ticket)
366                         return XFS_ERROR(ENOMEM);
367                 internal_ticket->t_trans_type = t_type;
368                 *ticket = internal_ticket;
369
370                 trace_xfs_log_reserve(log, internal_ticket);
371
372                 xlog_grant_push_ail(mp,
373                                     (internal_ticket->t_unit_res *
374                                      internal_ticket->t_cnt));
375                 retval = xlog_grant_log_space(log, internal_ticket);
376         }
377
378         return retval;
379 }       /* xfs_log_reserve */
380
381
382 /*
383  * Mount a log filesystem
384  *
385  * mp           - ubiquitous xfs mount point structure
386  * log_target   - buftarg of on-disk log device
387  * blk_offset   - Start block # where block size is 512 bytes (BBSIZE)
388  * num_bblocks  - Number of BBSIZE blocks in on-disk log
389  *
390  * Return error or zero.
391  */
392 int
393 xfs_log_mount(
394         xfs_mount_t     *mp,
395         xfs_buftarg_t   *log_target,
396         xfs_daddr_t     blk_offset,
397         int             num_bblks)
398 {
399         int             error;
400
401         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY))
402                 cmn_err(CE_NOTE, "XFS mounting filesystem %s", mp->m_fsname);
403         else {
404                 cmn_err(CE_NOTE,
405                         "!Mounting filesystem \"%s\" in no-recovery mode.  Filesystem will be inconsistent.",
406                         mp->m_fsname);
407                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
408         }
409
410         mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
411         if (IS_ERR(mp->m_log)) {
412                 error = -PTR_ERR(mp->m_log);
413                 goto out;
414         }
415
416         /*
417          * Initialize the AIL now we have a log.
418          */
419         error = xfs_trans_ail_init(mp);
420         if (error) {
421                 cmn_err(CE_WARN, "XFS: AIL initialisation failed: error %d", error);
422                 goto out_free_log;
423         }
424         mp->m_log->l_ailp = mp->m_ail;
425
426         /*
427          * skip log recovery on a norecovery mount.  pretend it all
428          * just worked.
429          */
430         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
431                 int     readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
432
433                 if (readonly)
434                         mp->m_flags &= ~XFS_MOUNT_RDONLY;
435
436                 error = xlog_recover(mp->m_log);
437
438                 if (readonly)
439                         mp->m_flags |= XFS_MOUNT_RDONLY;
440                 if (error) {
441                         cmn_err(CE_WARN, "XFS: log mount/recovery failed: error %d", error);
442                         goto out_destroy_ail;
443                 }
444         }
445
446         /* Normal transactions can now occur */
447         mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
448
449         /*
450          * Now the log has been fully initialised and we know were our
451          * space grant counters are, we can initialise the permanent ticket
452          * needed for delayed logging to work.
453          */
454         xlog_cil_init_post_recovery(mp->m_log);
455
456         return 0;
457
458 out_destroy_ail:
459         xfs_trans_ail_destroy(mp);
460 out_free_log:
461         xlog_dealloc_log(mp->m_log);
462 out:
463         return error;
464 }
465
466 /*
467  * Finish the recovery of the file system.  This is separate from
468  * the xfs_log_mount() call, because it depends on the code in
469  * xfs_mountfs() to read in the root and real-time bitmap inodes
470  * between calling xfs_log_mount() and here.
471  *
472  * mp           - ubiquitous xfs mount point structure
473  */
474 int
475 xfs_log_mount_finish(xfs_mount_t *mp)
476 {
477         int     error;
478
479         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY))
480                 error = xlog_recover_finish(mp->m_log);
481         else {
482                 error = 0;
483                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
484         }
485
486         return error;
487 }
488
489 /*
490  * Final log writes as part of unmount.
491  *
492  * Mark the filesystem clean as unmount happens.  Note that during relocation
493  * this routine needs to be executed as part of source-bag while the
494  * deallocation must not be done until source-end.
495  */
496
497 /*
498  * Unmount record used to have a string "Unmount filesystem--" in the
499  * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
500  * We just write the magic number now since that particular field isn't
501  * currently architecture converted and "nUmount" is a bit foo.
502  * As far as I know, there weren't any dependencies on the old behaviour.
503  */
504
505 int
506 xfs_log_unmount_write(xfs_mount_t *mp)
507 {
508         xlog_t           *log = mp->m_log;
509         xlog_in_core_t   *iclog;
510 #ifdef DEBUG
511         xlog_in_core_t   *first_iclog;
512 #endif
513         xlog_ticket_t   *tic = NULL;
514         xfs_lsn_t        lsn;
515         int              error;
516
517         /*
518          * Don't write out unmount record on read-only mounts.
519          * Or, if we are doing a forced umount (typically because of IO errors).
520          */
521         if (mp->m_flags & XFS_MOUNT_RDONLY)
522                 return 0;
523
524         error = _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
525         ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
526
527 #ifdef DEBUG
528         first_iclog = iclog = log->l_iclog;
529         do {
530                 if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
531                         ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
532                         ASSERT(iclog->ic_offset == 0);
533                 }
534                 iclog = iclog->ic_next;
535         } while (iclog != first_iclog);
536 #endif
537         if (! (XLOG_FORCED_SHUTDOWN(log))) {
538                 error = xfs_log_reserve(mp, 600, 1, &tic,
539                                         XFS_LOG, 0, XLOG_UNMOUNT_REC_TYPE);
540                 if (!error) {
541                         /* the data section must be 32 bit size aligned */
542                         struct {
543                             __uint16_t magic;
544                             __uint16_t pad1;
545                             __uint32_t pad2; /* may as well make it 64 bits */
546                         } magic = {
547                                 .magic = XLOG_UNMOUNT_TYPE,
548                         };
549                         struct xfs_log_iovec reg = {
550                                 .i_addr = &magic,
551                                 .i_len = sizeof(magic),
552                                 .i_type = XLOG_REG_TYPE_UNMOUNT,
553                         };
554                         struct xfs_log_vec vec = {
555                                 .lv_niovecs = 1,
556                                 .lv_iovecp = &reg,
557                         };
558
559                         /* remove inited flag */
560                         tic->t_flags = 0;
561                         error = xlog_write(log, &vec, tic, &lsn,
562                                            NULL, XLOG_UNMOUNT_TRANS);
563                         /*
564                          * At this point, we're umounting anyway,
565                          * so there's no point in transitioning log state
566                          * to IOERROR. Just continue...
567                          */
568                 }
569
570                 if (error) {
571                         xfs_fs_cmn_err(CE_ALERT, mp,
572                                 "xfs_log_unmount: unmount record failed");
573                 }
574
575
576                 spin_lock(&log->l_icloglock);
577                 iclog = log->l_iclog;
578                 atomic_inc(&iclog->ic_refcnt);
579                 xlog_state_want_sync(log, iclog);
580                 spin_unlock(&log->l_icloglock);
581                 error = xlog_state_release_iclog(log, iclog);
582
583                 spin_lock(&log->l_icloglock);
584                 if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
585                       iclog->ic_state == XLOG_STATE_DIRTY)) {
586                         if (!XLOG_FORCED_SHUTDOWN(log)) {
587                                 sv_wait(&iclog->ic_force_wait, PMEM,
588                                         &log->l_icloglock, s);
589                         } else {
590                                 spin_unlock(&log->l_icloglock);
591                         }
592                 } else {
593                         spin_unlock(&log->l_icloglock);
594                 }
595                 if (tic) {
596                         trace_xfs_log_umount_write(log, tic);
597                         xlog_ungrant_log_space(log, tic);
598                         xfs_log_ticket_put(tic);
599                 }
600         } else {
601                 /*
602                  * We're already in forced_shutdown mode, couldn't
603                  * even attempt to write out the unmount transaction.
604                  *
605                  * Go through the motions of sync'ing and releasing
606                  * the iclog, even though no I/O will actually happen,
607                  * we need to wait for other log I/Os that may already
608                  * be in progress.  Do this as a separate section of
609                  * code so we'll know if we ever get stuck here that
610                  * we're in this odd situation of trying to unmount
611                  * a file system that went into forced_shutdown as
612                  * the result of an unmount..
613                  */
614                 spin_lock(&log->l_icloglock);
615                 iclog = log->l_iclog;
616                 atomic_inc(&iclog->ic_refcnt);
617
618                 xlog_state_want_sync(log, iclog);
619                 spin_unlock(&log->l_icloglock);
620                 error =  xlog_state_release_iclog(log, iclog);
621
622                 spin_lock(&log->l_icloglock);
623
624                 if ( ! (   iclog->ic_state == XLOG_STATE_ACTIVE
625                         || iclog->ic_state == XLOG_STATE_DIRTY
626                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
627
628                                 sv_wait(&iclog->ic_force_wait, PMEM,
629                                         &log->l_icloglock, s);
630                 } else {
631                         spin_unlock(&log->l_icloglock);
632                 }
633         }
634
635         return error;
636 }       /* xfs_log_unmount_write */
637
638 /*
639  * Deallocate log structures for unmount/relocation.
640  *
641  * We need to stop the aild from running before we destroy
642  * and deallocate the log as the aild references the log.
643  */
644 void
645 xfs_log_unmount(xfs_mount_t *mp)
646 {
647         xfs_trans_ail_destroy(mp);
648         xlog_dealloc_log(mp->m_log);
649 }
650
651 void
652 xfs_log_item_init(
653         struct xfs_mount        *mp,
654         struct xfs_log_item     *item,
655         int                     type,
656         struct xfs_item_ops     *ops)
657 {
658         item->li_mountp = mp;
659         item->li_ailp = mp->m_ail;
660         item->li_type = type;
661         item->li_ops = ops;
662         item->li_lv = NULL;
663
664         INIT_LIST_HEAD(&item->li_ail);
665         INIT_LIST_HEAD(&item->li_cil);
666 }
667
668 /*
669  * Write region vectors to log.  The write happens using the space reservation
670  * of the ticket (tic).  It is not a requirement that all writes for a given
671  * transaction occur with one call to xfs_log_write(). However, it is important
672  * to note that the transaction reservation code makes an assumption about the
673  * number of log headers a transaction requires that may be violated if you
674  * don't pass all the transaction vectors in one call....
675  */
676 int
677 xfs_log_write(
678         struct xfs_mount        *mp,
679         struct xfs_log_iovec    reg[],
680         int                     nentries,
681         struct xlog_ticket      *tic,
682         xfs_lsn_t               *start_lsn)
683 {
684         struct log              *log = mp->m_log;
685         int                     error;
686         struct xfs_log_vec      vec = {
687                 .lv_niovecs = nentries,
688                 .lv_iovecp = reg,
689         };
690
691         if (XLOG_FORCED_SHUTDOWN(log))
692                 return XFS_ERROR(EIO);
693
694         error = xlog_write(log, &vec, tic, start_lsn, NULL, 0);
695         if (error)
696                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
697         return error;
698 }
699
700 void
701 xfs_log_move_tail(xfs_mount_t   *mp,
702                   xfs_lsn_t     tail_lsn)
703 {
704         xlog_ticket_t   *tic;
705         xlog_t          *log = mp->m_log;
706         int             need_bytes, free_bytes, cycle, bytes;
707
708         if (XLOG_FORCED_SHUTDOWN(log))
709                 return;
710
711         if (tail_lsn == 0) {
712                 /* needed since sync_lsn is 64 bits */
713                 spin_lock(&log->l_icloglock);
714                 tail_lsn = log->l_last_sync_lsn;
715                 spin_unlock(&log->l_icloglock);
716         }
717
718         spin_lock(&log->l_grant_lock);
719
720         /* Also an invalid lsn.  1 implies that we aren't passing in a valid
721          * tail_lsn.
722          */
723         if (tail_lsn != 1) {
724                 log->l_tail_lsn = tail_lsn;
725         }
726
727         if ((tic = log->l_write_headq)) {
728 #ifdef DEBUG
729                 if (log->l_flags & XLOG_ACTIVE_RECOVERY)
730                         panic("Recovery problem");
731 #endif
732                 cycle = log->l_grant_write_cycle;
733                 bytes = log->l_grant_write_bytes;
734                 free_bytes = xlog_space_left(log, cycle, bytes);
735                 do {
736                         ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
737
738                         if (free_bytes < tic->t_unit_res && tail_lsn != 1)
739                                 break;
740                         tail_lsn = 0;
741                         free_bytes -= tic->t_unit_res;
742                         sv_signal(&tic->t_wait);
743                         tic = tic->t_next;
744                 } while (tic != log->l_write_headq);
745         }
746         if ((tic = log->l_reserve_headq)) {
747 #ifdef DEBUG
748                 if (log->l_flags & XLOG_ACTIVE_RECOVERY)
749                         panic("Recovery problem");
750 #endif
751                 cycle = log->l_grant_reserve_cycle;
752                 bytes = log->l_grant_reserve_bytes;
753                 free_bytes = xlog_space_left(log, cycle, bytes);
754                 do {
755                         if (tic->t_flags & XLOG_TIC_PERM_RESERV)
756                                 need_bytes = tic->t_unit_res*tic->t_cnt;
757                         else
758                                 need_bytes = tic->t_unit_res;
759                         if (free_bytes < need_bytes && tail_lsn != 1)
760                                 break;
761                         tail_lsn = 0;
762                         free_bytes -= need_bytes;
763                         sv_signal(&tic->t_wait);
764                         tic = tic->t_next;
765                 } while (tic != log->l_reserve_headq);
766         }
767         spin_unlock(&log->l_grant_lock);
768 }       /* xfs_log_move_tail */
769
770 /*
771  * Determine if we have a transaction that has gone to disk
772  * that needs to be covered. To begin the transition to the idle state
773  * firstly the log needs to be idle (no AIL and nothing in the iclogs).
774  * If we are then in a state where covering is needed, the caller is informed
775  * that dummy transactions are required to move the log into the idle state.
776  *
777  * Because this is called as part of the sync process, we should also indicate
778  * that dummy transactions should be issued in anything but the covered or
779  * idle states. This ensures that the log tail is accurately reflected in
780  * the log at the end of the sync, hence if a crash occurrs avoids replay
781  * of transactions where the metadata is already on disk.
782  */
783 int
784 xfs_log_need_covered(xfs_mount_t *mp)
785 {
786         int             needed = 0;
787         xlog_t          *log = mp->m_log;
788
789         if (!xfs_fs_writable(mp))
790                 return 0;
791
792         spin_lock(&log->l_icloglock);
793         switch (log->l_covered_state) {
794         case XLOG_STATE_COVER_DONE:
795         case XLOG_STATE_COVER_DONE2:
796         case XLOG_STATE_COVER_IDLE:
797                 break;
798         case XLOG_STATE_COVER_NEED:
799         case XLOG_STATE_COVER_NEED2:
800                 if (!xfs_trans_ail_tail(log->l_ailp) &&
801                     xlog_iclogs_empty(log)) {
802                         if (log->l_covered_state == XLOG_STATE_COVER_NEED)
803                                 log->l_covered_state = XLOG_STATE_COVER_DONE;
804                         else
805                                 log->l_covered_state = XLOG_STATE_COVER_DONE2;
806                 }
807                 /* FALLTHRU */
808         default:
809                 needed = 1;
810                 break;
811         }
812         spin_unlock(&log->l_icloglock);
813         return needed;
814 }
815
816 /******************************************************************************
817  *
818  *      local routines
819  *
820  ******************************************************************************
821  */
822
823 /* xfs_trans_tail_ail returns 0 when there is nothing in the list.
824  * The log manager must keep track of the last LR which was committed
825  * to disk.  The lsn of this LR will become the new tail_lsn whenever
826  * xfs_trans_tail_ail returns 0.  If we don't do this, we run into
827  * the situation where stuff could be written into the log but nothing
828  * was ever in the AIL when asked.  Eventually, we panic since the
829  * tail hits the head.
830  *
831  * We may be holding the log iclog lock upon entering this routine.
832  */
833 xfs_lsn_t
834 xlog_assign_tail_lsn(xfs_mount_t *mp)
835 {
836         xfs_lsn_t tail_lsn;
837         xlog_t    *log = mp->m_log;
838
839         tail_lsn = xfs_trans_ail_tail(mp->m_ail);
840         spin_lock(&log->l_grant_lock);
841         if (tail_lsn != 0) {
842                 log->l_tail_lsn = tail_lsn;
843         } else {
844                 tail_lsn = log->l_tail_lsn = log->l_last_sync_lsn;
845         }
846         spin_unlock(&log->l_grant_lock);
847
848         return tail_lsn;
849 }       /* xlog_assign_tail_lsn */
850
851
852 /*
853  * Return the space in the log between the tail and the head.  The head
854  * is passed in the cycle/bytes formal parms.  In the special case where
855  * the reserve head has wrapped passed the tail, this calculation is no
856  * longer valid.  In this case, just return 0 which means there is no space
857  * in the log.  This works for all places where this function is called
858  * with the reserve head.  Of course, if the write head were to ever
859  * wrap the tail, we should blow up.  Rather than catch this case here,
860  * we depend on other ASSERTions in other parts of the code.   XXXmiken
861  *
862  * This code also handles the case where the reservation head is behind
863  * the tail.  The details of this case are described below, but the end
864  * result is that we return the size of the log as the amount of space left.
865  */
866 STATIC int
867 xlog_space_left(xlog_t *log, int cycle, int bytes)
868 {
869         int free_bytes;
870         int tail_bytes;
871         int tail_cycle;
872
873         tail_bytes = BBTOB(BLOCK_LSN(log->l_tail_lsn));
874         tail_cycle = CYCLE_LSN(log->l_tail_lsn);
875         if ((tail_cycle == cycle) && (bytes >= tail_bytes)) {
876                 free_bytes = log->l_logsize - (bytes - tail_bytes);
877         } else if ((tail_cycle + 1) < cycle) {
878                 return 0;
879         } else if (tail_cycle < cycle) {
880                 ASSERT(tail_cycle == (cycle - 1));
881                 free_bytes = tail_bytes - bytes;
882         } else {
883                 /*
884                  * The reservation head is behind the tail.
885                  * In this case we just want to return the size of the
886                  * log as the amount of space left.
887                  */
888                 xfs_fs_cmn_err(CE_ALERT, log->l_mp,
889                         "xlog_space_left: head behind tail\n"
890                         "  tail_cycle = %d, tail_bytes = %d\n"
891                         "  GH   cycle = %d, GH   bytes = %d",
892                         tail_cycle, tail_bytes, cycle, bytes);
893                 ASSERT(0);
894                 free_bytes = log->l_logsize;
895         }
896         return free_bytes;
897 }       /* xlog_space_left */
898
899
900 /*
901  * Log function which is called when an io completes.
902  *
903  * The log manager needs its own routine, in order to control what
904  * happens with the buffer after the write completes.
905  */
906 void
907 xlog_iodone(xfs_buf_t *bp)
908 {
909         xlog_in_core_t  *iclog;
910         xlog_t          *l;
911         int             aborted;
912
913         iclog = XFS_BUF_FSPRIVATE(bp, xlog_in_core_t *);
914         ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) == (unsigned long) 2);
915         XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
916         aborted = 0;
917         l = iclog->ic_log;
918
919         /*
920          * If the _XFS_BARRIER_FAILED flag was set by a lower
921          * layer, it means the underlying device no longer supports
922          * barrier I/O. Warn loudly and turn off barriers.
923          */
924         if (bp->b_flags & _XFS_BARRIER_FAILED) {
925                 bp->b_flags &= ~_XFS_BARRIER_FAILED;
926                 l->l_mp->m_flags &= ~XFS_MOUNT_BARRIER;
927                 xfs_fs_cmn_err(CE_WARN, l->l_mp,
928                                 "xlog_iodone: Barriers are no longer supported"
929                                 " by device. Disabling barriers\n");
930         }
931
932         /*
933          * Race to shutdown the filesystem if we see an error.
934          */
935         if (XFS_TEST_ERROR((XFS_BUF_GETERROR(bp)), l->l_mp,
936                         XFS_ERRTAG_IODONE_IOERR, XFS_RANDOM_IODONE_IOERR)) {
937                 xfs_ioerror_alert("xlog_iodone", l->l_mp, bp, XFS_BUF_ADDR(bp));
938                 XFS_BUF_STALE(bp);
939                 xfs_force_shutdown(l->l_mp, SHUTDOWN_LOG_IO_ERROR);
940                 /*
941                  * This flag will be propagated to the trans-committed
942                  * callback routines to let them know that the log-commit
943                  * didn't succeed.
944                  */
945                 aborted = XFS_LI_ABORTED;
946         } else if (iclog->ic_state & XLOG_STATE_IOERROR) {
947                 aborted = XFS_LI_ABORTED;
948         }
949
950         /* log I/O is always issued ASYNC */
951         ASSERT(XFS_BUF_ISASYNC(bp));
952         xlog_state_done_syncing(iclog, aborted);
953         /*
954          * do not reference the buffer (bp) here as we could race
955          * with it being freed after writing the unmount record to the
956          * log.
957          */
958
959 }       /* xlog_iodone */
960
961 /*
962  * Return size of each in-core log record buffer.
963  *
964  * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
965  *
966  * If the filesystem blocksize is too large, we may need to choose a
967  * larger size since the directory code currently logs entire blocks.
968  */
969
970 STATIC void
971 xlog_get_iclog_buffer_size(xfs_mount_t  *mp,
972                            xlog_t       *log)
973 {
974         int size;
975         int xhdrs;
976
977         if (mp->m_logbufs <= 0)
978                 log->l_iclog_bufs = XLOG_MAX_ICLOGS;
979         else
980                 log->l_iclog_bufs = mp->m_logbufs;
981
982         /*
983          * Buffer size passed in from mount system call.
984          */
985         if (mp->m_logbsize > 0) {
986                 size = log->l_iclog_size = mp->m_logbsize;
987                 log->l_iclog_size_log = 0;
988                 while (size != 1) {
989                         log->l_iclog_size_log++;
990                         size >>= 1;
991                 }
992
993                 if (xfs_sb_version_haslogv2(&mp->m_sb)) {
994                         /* # headers = size / 32k
995                          * one header holds cycles from 32k of data
996                          */
997
998                         xhdrs = mp->m_logbsize / XLOG_HEADER_CYCLE_SIZE;
999                         if (mp->m_logbsize % XLOG_HEADER_CYCLE_SIZE)
1000                                 xhdrs++;
1001                         log->l_iclog_hsize = xhdrs << BBSHIFT;
1002                         log->l_iclog_heads = xhdrs;
1003                 } else {
1004                         ASSERT(mp->m_logbsize <= XLOG_BIG_RECORD_BSIZE);
1005                         log->l_iclog_hsize = BBSIZE;
1006                         log->l_iclog_heads = 1;
1007                 }
1008                 goto done;
1009         }
1010
1011         /* All machines use 32kB buffers by default. */
1012         log->l_iclog_size = XLOG_BIG_RECORD_BSIZE;
1013         log->l_iclog_size_log = XLOG_BIG_RECORD_BSHIFT;
1014
1015         /* the default log size is 16k or 32k which is one header sector */
1016         log->l_iclog_hsize = BBSIZE;
1017         log->l_iclog_heads = 1;
1018
1019 done:
1020         /* are we being asked to make the sizes selected above visible? */
1021         if (mp->m_logbufs == 0)
1022                 mp->m_logbufs = log->l_iclog_bufs;
1023         if (mp->m_logbsize == 0)
1024                 mp->m_logbsize = log->l_iclog_size;
1025 }       /* xlog_get_iclog_buffer_size */
1026
1027
1028 /*
1029  * This routine initializes some of the log structure for a given mount point.
1030  * Its primary purpose is to fill in enough, so recovery can occur.  However,
1031  * some other stuff may be filled in too.
1032  */
1033 STATIC xlog_t *
1034 xlog_alloc_log(xfs_mount_t      *mp,
1035                xfs_buftarg_t    *log_target,
1036                xfs_daddr_t      blk_offset,
1037                int              num_bblks)
1038 {
1039         xlog_t                  *log;
1040         xlog_rec_header_t       *head;
1041         xlog_in_core_t          **iclogp;
1042         xlog_in_core_t          *iclog, *prev_iclog=NULL;
1043         xfs_buf_t               *bp;
1044         int                     i;
1045         int                     iclogsize;
1046         int                     error = ENOMEM;
1047         uint                    log2_size = 0;
1048
1049         log = kmem_zalloc(sizeof(xlog_t), KM_MAYFAIL);
1050         if (!log) {
1051                 xlog_warn("XFS: Log allocation failed: No memory!");
1052                 goto out;
1053         }
1054
1055         log->l_mp          = mp;
1056         log->l_targ        = log_target;
1057         log->l_logsize     = BBTOB(num_bblks);
1058         log->l_logBBstart  = blk_offset;
1059         log->l_logBBsize   = num_bblks;
1060         log->l_covered_state = XLOG_STATE_COVER_IDLE;
1061         log->l_flags       |= XLOG_ACTIVE_RECOVERY;
1062
1063         log->l_prev_block  = -1;
1064         log->l_tail_lsn    = xlog_assign_lsn(1, 0);
1065         /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1066         log->l_last_sync_lsn = log->l_tail_lsn;
1067         log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
1068         log->l_grant_reserve_cycle = 1;
1069         log->l_grant_write_cycle = 1;
1070
1071         error = EFSCORRUPTED;
1072         if (xfs_sb_version_hassector(&mp->m_sb)) {
1073                 log2_size = mp->m_sb.sb_logsectlog;
1074                 if (log2_size < BBSHIFT) {
1075                         xlog_warn("XFS: Log sector size too small "
1076                                 "(0x%x < 0x%x)", log2_size, BBSHIFT);
1077                         goto out_free_log;
1078                 }
1079
1080                 log2_size -= BBSHIFT;
1081                 if (log2_size > mp->m_sectbb_log) {
1082                         xlog_warn("XFS: Log sector size too large "
1083                                 "(0x%x > 0x%x)", log2_size, mp->m_sectbb_log);
1084                         goto out_free_log;
1085                 }
1086
1087                 /* for larger sector sizes, must have v2 or external log */
1088                 if (log2_size && log->l_logBBstart > 0 &&
1089                             !xfs_sb_version_haslogv2(&mp->m_sb)) {
1090
1091                         xlog_warn("XFS: log sector size (0x%x) invalid "
1092                                   "for configuration.", log2_size);
1093                         goto out_free_log;
1094                 }
1095         }
1096         log->l_sectBBsize = 1 << log2_size;
1097
1098         xlog_get_iclog_buffer_size(mp, log);
1099
1100         error = ENOMEM;
1101         bp = xfs_buf_get_empty(log->l_iclog_size, mp->m_logdev_targp);
1102         if (!bp)
1103                 goto out_free_log;
1104         XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
1105         XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
1106         ASSERT(XFS_BUF_ISBUSY(bp));
1107         ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
1108         log->l_xbuf = bp;
1109
1110         spin_lock_init(&log->l_icloglock);
1111         spin_lock_init(&log->l_grant_lock);
1112         sv_init(&log->l_flush_wait, 0, "flush_wait");
1113
1114         /* log record size must be multiple of BBSIZE; see xlog_rec_header_t */
1115         ASSERT((XFS_BUF_SIZE(bp) & BBMASK) == 0);
1116
1117         iclogp = &log->l_iclog;
1118         /*
1119          * The amount of memory to allocate for the iclog structure is
1120          * rather funky due to the way the structure is defined.  It is
1121          * done this way so that we can use different sizes for machines
1122          * with different amounts of memory.  See the definition of
1123          * xlog_in_core_t in xfs_log_priv.h for details.
1124          */
1125         iclogsize = log->l_iclog_size;
1126         ASSERT(log->l_iclog_size >= 4096);
1127         for (i=0; i < log->l_iclog_bufs; i++) {
1128                 *iclogp = kmem_zalloc(sizeof(xlog_in_core_t), KM_MAYFAIL);
1129                 if (!*iclogp)
1130                         goto out_free_iclog;
1131
1132                 iclog = *iclogp;
1133                 iclog->ic_prev = prev_iclog;
1134                 prev_iclog = iclog;
1135
1136                 bp = xfs_buf_get_noaddr(log->l_iclog_size, mp->m_logdev_targp);
1137                 if (!bp)
1138                         goto out_free_iclog;
1139                 if (!XFS_BUF_CPSEMA(bp))
1140                         ASSERT(0);
1141                 XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
1142                 XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
1143                 iclog->ic_bp = bp;
1144                 iclog->ic_data = bp->b_addr;
1145 #ifdef DEBUG
1146                 log->l_iclog_bak[i] = (xfs_caddr_t)&(iclog->ic_header);
1147 #endif
1148                 head = &iclog->ic_header;
1149                 memset(head, 0, sizeof(xlog_rec_header_t));
1150                 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1151                 head->h_version = cpu_to_be32(
1152                         xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1153                 head->h_size = cpu_to_be32(log->l_iclog_size);
1154                 /* new fields */
1155                 head->h_fmt = cpu_to_be32(XLOG_FMT);
1156                 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1157
1158                 iclog->ic_size = XFS_BUF_SIZE(bp) - log->l_iclog_hsize;
1159                 iclog->ic_state = XLOG_STATE_ACTIVE;
1160                 iclog->ic_log = log;
1161                 atomic_set(&iclog->ic_refcnt, 0);
1162                 spin_lock_init(&iclog->ic_callback_lock);
1163                 iclog->ic_callback_tail = &(iclog->ic_callback);
1164                 iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1165
1166                 ASSERT(XFS_BUF_ISBUSY(iclog->ic_bp));
1167                 ASSERT(XFS_BUF_VALUSEMA(iclog->ic_bp) <= 0);
1168                 sv_init(&iclog->ic_force_wait, SV_DEFAULT, "iclog-force");
1169                 sv_init(&iclog->ic_write_wait, SV_DEFAULT, "iclog-write");
1170
1171                 iclogp = &iclog->ic_next;
1172         }
1173         *iclogp = log->l_iclog;                 /* complete ring */
1174         log->l_iclog->ic_prev = prev_iclog;     /* re-write 1st prev ptr */
1175
1176         error = xlog_cil_init(log);
1177         if (error)
1178                 goto out_free_iclog;
1179         return log;
1180
1181 out_free_iclog:
1182         for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1183                 prev_iclog = iclog->ic_next;
1184                 if (iclog->ic_bp) {
1185                         sv_destroy(&iclog->ic_force_wait);
1186                         sv_destroy(&iclog->ic_write_wait);
1187                         xfs_buf_free(iclog->ic_bp);
1188                 }
1189                 kmem_free(iclog);
1190         }
1191         spinlock_destroy(&log->l_icloglock);
1192         spinlock_destroy(&log->l_grant_lock);
1193         xfs_buf_free(log->l_xbuf);
1194 out_free_log:
1195         kmem_free(log);
1196 out:
1197         return ERR_PTR(-error);
1198 }       /* xlog_alloc_log */
1199
1200
1201 /*
1202  * Write out the commit record of a transaction associated with the given
1203  * ticket.  Return the lsn of the commit record.
1204  */
1205 STATIC int
1206 xlog_commit_record(
1207         struct log              *log,
1208         struct xlog_ticket      *ticket,
1209         struct xlog_in_core     **iclog,
1210         xfs_lsn_t               *commitlsnp)
1211 {
1212         struct xfs_mount *mp = log->l_mp;
1213         int     error;
1214         struct xfs_log_iovec reg = {
1215                 .i_addr = NULL,
1216                 .i_len = 0,
1217                 .i_type = XLOG_REG_TYPE_COMMIT,
1218         };
1219         struct xfs_log_vec vec = {
1220                 .lv_niovecs = 1,
1221                 .lv_iovecp = &reg,
1222         };
1223
1224         ASSERT_ALWAYS(iclog);
1225         error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
1226                                         XLOG_COMMIT_TRANS);
1227         if (error)
1228                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
1229         return error;
1230 }
1231
1232 /*
1233  * Push on the buffer cache code if we ever use more than 75% of the on-disk
1234  * log space.  This code pushes on the lsn which would supposedly free up
1235  * the 25% which we want to leave free.  We may need to adopt a policy which
1236  * pushes on an lsn which is further along in the log once we reach the high
1237  * water mark.  In this manner, we would be creating a low water mark.
1238  */
1239 STATIC void
1240 xlog_grant_push_ail(xfs_mount_t *mp,
1241                     int         need_bytes)
1242 {
1243     xlog_t      *log = mp->m_log;       /* pointer to the log */
1244     xfs_lsn_t   tail_lsn;               /* lsn of the log tail */
1245     xfs_lsn_t   threshold_lsn = 0;      /* lsn we'd like to be at */
1246     int         free_blocks;            /* free blocks left to write to */
1247     int         free_bytes;             /* free bytes left to write to */
1248     int         threshold_block;        /* block in lsn we'd like to be at */
1249     int         threshold_cycle;        /* lsn cycle we'd like to be at */
1250     int         free_threshold;
1251
1252     ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1253
1254     spin_lock(&log->l_grant_lock);
1255     free_bytes = xlog_space_left(log,
1256                                  log->l_grant_reserve_cycle,
1257                                  log->l_grant_reserve_bytes);
1258     tail_lsn = log->l_tail_lsn;
1259     free_blocks = BTOBBT(free_bytes);
1260
1261     /*
1262      * Set the threshold for the minimum number of free blocks in the
1263      * log to the maximum of what the caller needs, one quarter of the
1264      * log, and 256 blocks.
1265      */
1266     free_threshold = BTOBB(need_bytes);
1267     free_threshold = MAX(free_threshold, (log->l_logBBsize >> 2));
1268     free_threshold = MAX(free_threshold, 256);
1269     if (free_blocks < free_threshold) {
1270         threshold_block = BLOCK_LSN(tail_lsn) + free_threshold;
1271         threshold_cycle = CYCLE_LSN(tail_lsn);
1272         if (threshold_block >= log->l_logBBsize) {
1273             threshold_block -= log->l_logBBsize;
1274             threshold_cycle += 1;
1275         }
1276         threshold_lsn = xlog_assign_lsn(threshold_cycle, threshold_block);
1277
1278         /* Don't pass in an lsn greater than the lsn of the last
1279          * log record known to be on disk.
1280          */
1281         if (XFS_LSN_CMP(threshold_lsn, log->l_last_sync_lsn) > 0)
1282             threshold_lsn = log->l_last_sync_lsn;
1283     }
1284     spin_unlock(&log->l_grant_lock);
1285
1286     /*
1287      * Get the transaction layer to kick the dirty buffers out to
1288      * disk asynchronously. No point in trying to do this if
1289      * the filesystem is shutting down.
1290      */
1291     if (threshold_lsn &&
1292         !XLOG_FORCED_SHUTDOWN(log))
1293             xfs_trans_ail_push(log->l_ailp, threshold_lsn);
1294 }       /* xlog_grant_push_ail */
1295
1296 /*
1297  * The bdstrat callback function for log bufs. This gives us a central
1298  * place to trap bufs in case we get hit by a log I/O error and need to
1299  * shutdown. Actually, in practice, even when we didn't get a log error,
1300  * we transition the iclogs to IOERROR state *after* flushing all existing
1301  * iclogs to disk. This is because we don't want anymore new transactions to be
1302  * started or completed afterwards.
1303  */
1304 STATIC int
1305 xlog_bdstrat(
1306         struct xfs_buf          *bp)
1307 {
1308         struct xlog_in_core     *iclog;
1309
1310         iclog = XFS_BUF_FSPRIVATE(bp, xlog_in_core_t *);
1311         if (iclog->ic_state & XLOG_STATE_IOERROR) {
1312                 XFS_BUF_ERROR(bp, EIO);
1313                 XFS_BUF_STALE(bp);
1314                 xfs_biodone(bp);
1315                 /*
1316                  * It would seem logical to return EIO here, but we rely on
1317                  * the log state machine to propagate I/O errors instead of
1318                  * doing it here.
1319                  */
1320                 return 0;
1321         }
1322
1323         bp->b_flags |= _XBF_RUN_QUEUES;
1324         xfs_buf_iorequest(bp);
1325         return 0;
1326 }
1327
1328 /*
1329  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous 
1330  * fashion.  Previously, we should have moved the current iclog
1331  * ptr in the log to point to the next available iclog.  This allows further
1332  * write to continue while this code syncs out an iclog ready to go.
1333  * Before an in-core log can be written out, the data section must be scanned
1334  * to save away the 1st word of each BBSIZE block into the header.  We replace
1335  * it with the current cycle count.  Each BBSIZE block is tagged with the
1336  * cycle count because there in an implicit assumption that drives will
1337  * guarantee that entire 512 byte blocks get written at once.  In other words,
1338  * we can't have part of a 512 byte block written and part not written.  By
1339  * tagging each block, we will know which blocks are valid when recovering
1340  * after an unclean shutdown.
1341  *
1342  * This routine is single threaded on the iclog.  No other thread can be in
1343  * this routine with the same iclog.  Changing contents of iclog can there-
1344  * fore be done without grabbing the state machine lock.  Updating the global
1345  * log will require grabbing the lock though.
1346  *
1347  * The entire log manager uses a logical block numbering scheme.  Only
1348  * log_sync (and then only bwrite()) know about the fact that the log may
1349  * not start with block zero on a given device.  The log block start offset
1350  * is added immediately before calling bwrite().
1351  */
1352
1353 STATIC int
1354 xlog_sync(xlog_t                *log,
1355           xlog_in_core_t        *iclog)
1356 {
1357         xfs_caddr_t     dptr;           /* pointer to byte sized element */
1358         xfs_buf_t       *bp;
1359         int             i;
1360         uint            count;          /* byte count of bwrite */
1361         uint            count_init;     /* initial count before roundup */
1362         int             roundoff;       /* roundoff to BB or stripe */
1363         int             split = 0;      /* split write into two regions */
1364         int             error;
1365         int             v2 = xfs_sb_version_haslogv2(&log->l_mp->m_sb);
1366
1367         XFS_STATS_INC(xs_log_writes);
1368         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1369
1370         /* Add for LR header */
1371         count_init = log->l_iclog_hsize + iclog->ic_offset;
1372
1373         /* Round out the log write size */
1374         if (v2 && log->l_mp->m_sb.sb_logsunit > 1) {
1375                 /* we have a v2 stripe unit to use */
1376                 count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1377         } else {
1378                 count = BBTOB(BTOBB(count_init));
1379         }
1380         roundoff = count - count_init;
1381         ASSERT(roundoff >= 0);
1382         ASSERT((v2 && log->l_mp->m_sb.sb_logsunit > 1 && 
1383                 roundoff < log->l_mp->m_sb.sb_logsunit)
1384                 || 
1385                 (log->l_mp->m_sb.sb_logsunit <= 1 && 
1386                  roundoff < BBTOB(1)));
1387
1388         /* move grant heads by roundoff in sync */
1389         spin_lock(&log->l_grant_lock);
1390         xlog_grant_add_space(log, roundoff);
1391         spin_unlock(&log->l_grant_lock);
1392
1393         /* put cycle number in every block */
1394         xlog_pack_data(log, iclog, roundoff); 
1395
1396         /* real byte length */
1397         if (v2) {
1398                 iclog->ic_header.h_len =
1399                         cpu_to_be32(iclog->ic_offset + roundoff);
1400         } else {
1401                 iclog->ic_header.h_len =
1402                         cpu_to_be32(iclog->ic_offset);
1403         }
1404
1405         bp = iclog->ic_bp;
1406         ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) == (unsigned long)1);
1407         XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)2);
1408         XFS_BUF_SET_ADDR(bp, BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn)));
1409
1410         XFS_STATS_ADD(xs_log_blocks, BTOBB(count));
1411
1412         /* Do we need to split this write into 2 parts? */
1413         if (XFS_BUF_ADDR(bp) + BTOBB(count) > log->l_logBBsize) {
1414                 split = count - (BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp)));
1415                 count = BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp));
1416                 iclog->ic_bwritecnt = 2;        /* split into 2 writes */
1417         } else {
1418                 iclog->ic_bwritecnt = 1;
1419         }
1420         XFS_BUF_SET_COUNT(bp, count);
1421         XFS_BUF_SET_FSPRIVATE(bp, iclog);       /* save for later */
1422         XFS_BUF_ZEROFLAGS(bp);
1423         XFS_BUF_BUSY(bp);
1424         XFS_BUF_ASYNC(bp);
1425         bp->b_flags |= XBF_LOG_BUFFER;
1426
1427         if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
1428                 XFS_BUF_ORDERED(bp);
1429
1430         ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
1431         ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
1432
1433         xlog_verify_iclog(log, iclog, count, B_TRUE);
1434
1435         /* account for log which doesn't start at block #0 */
1436         XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
1437         /*
1438          * Don't call xfs_bwrite here. We do log-syncs even when the filesystem
1439          * is shutting down.
1440          */
1441         XFS_BUF_WRITE(bp);
1442
1443         if ((error = xlog_bdstrat(bp))) {
1444                 xfs_ioerror_alert("xlog_sync", log->l_mp, bp,
1445                                   XFS_BUF_ADDR(bp));
1446                 return error;
1447         }
1448         if (split) {
1449                 bp = iclog->ic_log->l_xbuf;
1450                 ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) ==
1451                                                         (unsigned long)1);
1452                 XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)2);
1453                 XFS_BUF_SET_ADDR(bp, 0);             /* logical 0 */
1454                 XFS_BUF_SET_PTR(bp, (xfs_caddr_t)((__psint_t)&(iclog->ic_header)+
1455                                             (__psint_t)count), split);
1456                 XFS_BUF_SET_FSPRIVATE(bp, iclog);
1457                 XFS_BUF_ZEROFLAGS(bp);
1458                 XFS_BUF_BUSY(bp);
1459                 XFS_BUF_ASYNC(bp);
1460                 bp->b_flags |= XBF_LOG_BUFFER;
1461                 if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
1462                         XFS_BUF_ORDERED(bp);
1463                 dptr = XFS_BUF_PTR(bp);
1464                 /*
1465                  * Bump the cycle numbers at the start of each block
1466                  * since this part of the buffer is at the start of
1467                  * a new cycle.  Watch out for the header magic number
1468                  * case, though.
1469                  */
1470                 for (i = 0; i < split; i += BBSIZE) {
1471                         be32_add_cpu((__be32 *)dptr, 1);
1472                         if (be32_to_cpu(*(__be32 *)dptr) == XLOG_HEADER_MAGIC_NUM)
1473                                 be32_add_cpu((__be32 *)dptr, 1);
1474                         dptr += BBSIZE;
1475                 }
1476
1477                 ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
1478                 ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
1479
1480                 /* account for internal log which doesn't start at block #0 */
1481                 XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
1482                 XFS_BUF_WRITE(bp);
1483                 if ((error = xlog_bdstrat(bp))) {
1484                         xfs_ioerror_alert("xlog_sync (split)", log->l_mp,
1485                                           bp, XFS_BUF_ADDR(bp));
1486                         return error;
1487                 }
1488         }
1489         return 0;
1490 }       /* xlog_sync */
1491
1492
1493 /*
1494  * Deallocate a log structure
1495  */
1496 STATIC void
1497 xlog_dealloc_log(xlog_t *log)
1498 {
1499         xlog_in_core_t  *iclog, *next_iclog;
1500         int             i;
1501
1502         xlog_cil_destroy(log);
1503
1504         iclog = log->l_iclog;
1505         for (i=0; i<log->l_iclog_bufs; i++) {
1506                 sv_destroy(&iclog->ic_force_wait);
1507                 sv_destroy(&iclog->ic_write_wait);
1508                 xfs_buf_free(iclog->ic_bp);
1509                 next_iclog = iclog->ic_next;
1510                 kmem_free(iclog);
1511                 iclog = next_iclog;
1512         }
1513         spinlock_destroy(&log->l_icloglock);
1514         spinlock_destroy(&log->l_grant_lock);
1515
1516         xfs_buf_free(log->l_xbuf);
1517         log->l_mp->m_log = NULL;
1518         kmem_free(log);
1519 }       /* xlog_dealloc_log */
1520
1521 /*
1522  * Update counters atomically now that memcpy is done.
1523  */
1524 /* ARGSUSED */
1525 static inline void
1526 xlog_state_finish_copy(xlog_t           *log,
1527                        xlog_in_core_t   *iclog,
1528                        int              record_cnt,
1529                        int              copy_bytes)
1530 {
1531         spin_lock(&log->l_icloglock);
1532
1533         be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1534         iclog->ic_offset += copy_bytes;
1535
1536         spin_unlock(&log->l_icloglock);
1537 }       /* xlog_state_finish_copy */
1538
1539
1540
1541
1542 /*
1543  * print out info relating to regions written which consume
1544  * the reservation
1545  */
1546 void
1547 xlog_print_tic_res(
1548         struct xfs_mount        *mp,
1549         struct xlog_ticket      *ticket)
1550 {
1551         uint i;
1552         uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
1553
1554         /* match with XLOG_REG_TYPE_* in xfs_log.h */
1555         static char *res_type_str[XLOG_REG_TYPE_MAX] = {
1556             "bformat",
1557             "bchunk",
1558             "efi_format",
1559             "efd_format",
1560             "iformat",
1561             "icore",
1562             "iext",
1563             "ibroot",
1564             "ilocal",
1565             "iattr_ext",
1566             "iattr_broot",
1567             "iattr_local",
1568             "qformat",
1569             "dquot",
1570             "quotaoff",
1571             "LR header",
1572             "unmount",
1573             "commit",
1574             "trans header"
1575         };
1576         static char *trans_type_str[XFS_TRANS_TYPE_MAX] = {
1577             "SETATTR_NOT_SIZE",
1578             "SETATTR_SIZE",
1579             "INACTIVE",
1580             "CREATE",
1581             "CREATE_TRUNC",
1582             "TRUNCATE_FILE",
1583             "REMOVE",
1584             "LINK",
1585             "RENAME",
1586             "MKDIR",
1587             "RMDIR",
1588             "SYMLINK",
1589             "SET_DMATTRS",
1590             "GROWFS",
1591             "STRAT_WRITE",
1592             "DIOSTRAT",
1593             "WRITE_SYNC",
1594             "WRITEID",
1595             "ADDAFORK",
1596             "ATTRINVAL",
1597             "ATRUNCATE",
1598             "ATTR_SET",
1599             "ATTR_RM",
1600             "ATTR_FLAG",
1601             "CLEAR_AGI_BUCKET",
1602             "QM_SBCHANGE",
1603             "DUMMY1",
1604             "DUMMY2",
1605             "QM_QUOTAOFF",
1606             "QM_DQALLOC",
1607             "QM_SETQLIM",
1608             "QM_DQCLUSTER",
1609             "QM_QINOCREATE",
1610             "QM_QUOTAOFF_END",
1611             "SB_UNIT",
1612             "FSYNC_TS",
1613             "GROWFSRT_ALLOC",
1614             "GROWFSRT_ZERO",
1615             "GROWFSRT_FREE",
1616             "SWAPEXT"
1617         };
1618
1619         xfs_fs_cmn_err(CE_WARN, mp,
1620                         "xfs_log_write: reservation summary:\n"
1621                         "  trans type  = %s (%u)\n"
1622                         "  unit res    = %d bytes\n"
1623                         "  current res = %d bytes\n"
1624                         "  total reg   = %u bytes (o/flow = %u bytes)\n"
1625                         "  ophdrs      = %u (ophdr space = %u bytes)\n"
1626                         "  ophdr + reg = %u bytes\n"
1627                         "  num regions = %u\n",
1628                         ((ticket->t_trans_type <= 0 ||
1629                           ticket->t_trans_type > XFS_TRANS_TYPE_MAX) ?
1630                           "bad-trans-type" : trans_type_str[ticket->t_trans_type-1]),
1631                         ticket->t_trans_type,
1632                         ticket->t_unit_res,
1633                         ticket->t_curr_res,
1634                         ticket->t_res_arr_sum, ticket->t_res_o_flow,
1635                         ticket->t_res_num_ophdrs, ophdr_spc,
1636                         ticket->t_res_arr_sum + 
1637                         ticket->t_res_o_flow + ophdr_spc,
1638                         ticket->t_res_num);
1639
1640         for (i = 0; i < ticket->t_res_num; i++) {
1641                 uint r_type = ticket->t_res_arr[i].r_type; 
1642                 cmn_err(CE_WARN,
1643                             "region[%u]: %s - %u bytes\n",
1644                             i, 
1645                             ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
1646                             "bad-rtype" : res_type_str[r_type-1]),
1647                             ticket->t_res_arr[i].r_len);
1648         }
1649
1650         xfs_cmn_err(XFS_PTAG_LOGRES, CE_ALERT, mp,
1651                 "xfs_log_write: reservation ran out. Need to up reservation");
1652         xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1653 }
1654
1655 /*
1656  * Calculate the potential space needed by the log vector.  Each region gets
1657  * its own xlog_op_header_t and may need to be double word aligned.
1658  */
1659 static int
1660 xlog_write_calc_vec_length(
1661         struct xlog_ticket      *ticket,
1662         struct xfs_log_vec      *log_vector)
1663 {
1664         struct xfs_log_vec      *lv;
1665         int                     headers = 0;
1666         int                     len = 0;
1667         int                     i;
1668
1669         /* acct for start rec of xact */
1670         if (ticket->t_flags & XLOG_TIC_INITED)
1671                 headers++;
1672
1673         for (lv = log_vector; lv; lv = lv->lv_next) {
1674                 headers += lv->lv_niovecs;
1675
1676                 for (i = 0; i < lv->lv_niovecs; i++) {
1677                         struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
1678
1679                         len += vecp->i_len;
1680                         xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
1681                 }
1682         }
1683
1684         ticket->t_res_num_ophdrs += headers;
1685         len += headers * sizeof(struct xlog_op_header);
1686
1687         return len;
1688 }
1689
1690 /*
1691  * If first write for transaction, insert start record  We can't be trying to
1692  * commit if we are inited.  We can't have any "partial_copy" if we are inited.
1693  */
1694 static int
1695 xlog_write_start_rec(
1696         struct xlog_op_header   *ophdr,
1697         struct xlog_ticket      *ticket)
1698 {
1699         if (!(ticket->t_flags & XLOG_TIC_INITED))
1700                 return 0;
1701
1702         ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
1703         ophdr->oh_clientid = ticket->t_clientid;
1704         ophdr->oh_len = 0;
1705         ophdr->oh_flags = XLOG_START_TRANS;
1706         ophdr->oh_res2 = 0;
1707
1708         ticket->t_flags &= ~XLOG_TIC_INITED;
1709
1710         return sizeof(struct xlog_op_header);
1711 }
1712
1713 static xlog_op_header_t *
1714 xlog_write_setup_ophdr(
1715         struct log              *log,
1716         struct xlog_op_header   *ophdr,
1717         struct xlog_ticket      *ticket,
1718         uint                    flags)
1719 {
1720         ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
1721         ophdr->oh_clientid = ticket->t_clientid;
1722         ophdr->oh_res2 = 0;
1723
1724         /* are we copying a commit or unmount record? */
1725         ophdr->oh_flags = flags;
1726
1727         /*
1728          * We've seen logs corrupted with bad transaction client ids.  This
1729          * makes sure that XFS doesn't generate them on.  Turn this into an EIO
1730          * and shut down the filesystem.
1731          */
1732         switch (ophdr->oh_clientid)  {
1733         case XFS_TRANSACTION:
1734         case XFS_VOLUME:
1735         case XFS_LOG:
1736                 break;
1737         default:
1738                 xfs_fs_cmn_err(CE_WARN, log->l_mp,
1739                         "Bad XFS transaction clientid 0x%x in ticket 0x%p",
1740                         ophdr->oh_clientid, ticket);
1741                 return NULL;
1742         }
1743
1744         return ophdr;
1745 }
1746
1747 /*
1748  * Set up the parameters of the region copy into the log. This has
1749  * to handle region write split across multiple log buffers - this
1750  * state is kept external to this function so that this code can
1751  * can be written in an obvious, self documenting manner.
1752  */
1753 static int
1754 xlog_write_setup_copy(
1755         struct xlog_ticket      *ticket,
1756         struct xlog_op_header   *ophdr,
1757         int                     space_available,
1758         int                     space_required,
1759         int                     *copy_off,
1760         int                     *copy_len,
1761         int                     *last_was_partial_copy,
1762         int                     *bytes_consumed)
1763 {
1764         int                     still_to_copy;
1765
1766         still_to_copy = space_required - *bytes_consumed;
1767         *copy_off = *bytes_consumed;
1768
1769         if (still_to_copy <= space_available) {
1770                 /* write of region completes here */
1771                 *copy_len = still_to_copy;
1772                 ophdr->oh_len = cpu_to_be32(*copy_len);
1773                 if (*last_was_partial_copy)
1774                         ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
1775                 *last_was_partial_copy = 0;
1776                 *bytes_consumed = 0;
1777                 return 0;
1778         }
1779
1780         /* partial write of region, needs extra log op header reservation */
1781         *copy_len = space_available;
1782         ophdr->oh_len = cpu_to_be32(*copy_len);
1783         ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
1784         if (*last_was_partial_copy)
1785                 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
1786         *bytes_consumed += *copy_len;
1787         (*last_was_partial_copy)++;
1788
1789         /* account for new log op header */
1790         ticket->t_curr_res -= sizeof(struct xlog_op_header);
1791         ticket->t_res_num_ophdrs++;
1792
1793         return sizeof(struct xlog_op_header);
1794 }
1795
1796 static int
1797 xlog_write_copy_finish(
1798         struct log              *log,
1799         struct xlog_in_core     *iclog,
1800         uint                    flags,
1801         int                     *record_cnt,
1802         int                     *data_cnt,
1803         int                     *partial_copy,
1804         int                     *partial_copy_len,
1805         int                     log_offset,
1806         struct xlog_in_core     **commit_iclog)
1807 {
1808         if (*partial_copy) {
1809                 /*
1810                  * This iclog has already been marked WANT_SYNC by
1811                  * xlog_state_get_iclog_space.
1812                  */
1813                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
1814                 *record_cnt = 0;
1815                 *data_cnt = 0;
1816                 return xlog_state_release_iclog(log, iclog);
1817         }
1818
1819         *partial_copy = 0;
1820         *partial_copy_len = 0;
1821
1822         if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
1823                 /* no more space in this iclog - push it. */
1824                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
1825                 *record_cnt = 0;
1826                 *data_cnt = 0;
1827
1828                 spin_lock(&log->l_icloglock);
1829                 xlog_state_want_sync(log, iclog);
1830                 spin_unlock(&log->l_icloglock);
1831
1832                 if (!commit_iclog)
1833                         return xlog_state_release_iclog(log, iclog);
1834                 ASSERT(flags & XLOG_COMMIT_TRANS);
1835                 *commit_iclog = iclog;
1836         }
1837
1838         return 0;
1839 }
1840
1841 /*
1842  * Write some region out to in-core log
1843  *
1844  * This will be called when writing externally provided regions or when
1845  * writing out a commit record for a given transaction.
1846  *
1847  * General algorithm:
1848  *      1. Find total length of this write.  This may include adding to the
1849  *              lengths passed in.
1850  *      2. Check whether we violate the tickets reservation.
1851  *      3. While writing to this iclog
1852  *          A. Reserve as much space in this iclog as can get
1853  *          B. If this is first write, save away start lsn
1854  *          C. While writing this region:
1855  *              1. If first write of transaction, write start record
1856  *              2. Write log operation header (header per region)
1857  *              3. Find out if we can fit entire region into this iclog
1858  *              4. Potentially, verify destination memcpy ptr
1859  *              5. Memcpy (partial) region
1860  *              6. If partial copy, release iclog; otherwise, continue
1861  *                      copying more regions into current iclog
1862  *      4. Mark want sync bit (in simulation mode)
1863  *      5. Release iclog for potential flush to on-disk log.
1864  *
1865  * ERRORS:
1866  * 1.   Panic if reservation is overrun.  This should never happen since
1867  *      reservation amounts are generated internal to the filesystem.
1868  * NOTES:
1869  * 1. Tickets are single threaded data structures.
1870  * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
1871  *      syncing routine.  When a single log_write region needs to span
1872  *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
1873  *      on all log operation writes which don't contain the end of the
1874  *      region.  The XLOG_END_TRANS bit is used for the in-core log
1875  *      operation which contains the end of the continued log_write region.
1876  * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
1877  *      we don't really know exactly how much space will be used.  As a result,
1878  *      we don't update ic_offset until the end when we know exactly how many
1879  *      bytes have been written out.
1880  */
1881 int
1882 xlog_write(
1883         struct log              *log,
1884         struct xfs_log_vec      *log_vector,
1885         struct xlog_ticket      *ticket,
1886         xfs_lsn_t               *start_lsn,
1887         struct xlog_in_core     **commit_iclog,
1888         uint                    flags)
1889 {
1890         struct xlog_in_core     *iclog = NULL;
1891         struct xfs_log_iovec    *vecp;
1892         struct xfs_log_vec      *lv;
1893         int                     len;
1894         int                     index;
1895         int                     partial_copy = 0;
1896         int                     partial_copy_len = 0;
1897         int                     contwr = 0;
1898         int                     record_cnt = 0;
1899         int                     data_cnt = 0;
1900         int                     error;
1901
1902         *start_lsn = 0;
1903
1904         len = xlog_write_calc_vec_length(ticket, log_vector);
1905         if (log->l_cilp) {
1906                 /*
1907                  * Region headers and bytes are already accounted for.
1908                  * We only need to take into account start records and
1909                  * split regions in this function.
1910                  */
1911                 if (ticket->t_flags & XLOG_TIC_INITED)
1912                         ticket->t_curr_res -= sizeof(xlog_op_header_t);
1913
1914                 /*
1915                  * Commit record headers need to be accounted for. These
1916                  * come in as separate writes so are easy to detect.
1917                  */
1918                 if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
1919                         ticket->t_curr_res -= sizeof(xlog_op_header_t);
1920         } else
1921                 ticket->t_curr_res -= len;
1922
1923         if (ticket->t_curr_res < 0)
1924                 xlog_print_tic_res(log->l_mp, ticket);
1925
1926         index = 0;
1927         lv = log_vector;
1928         vecp = lv->lv_iovecp;
1929         while (lv && index < lv->lv_niovecs) {
1930                 void            *ptr;
1931                 int             log_offset;
1932
1933                 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
1934                                                    &contwr, &log_offset);
1935                 if (error)
1936                         return error;
1937
1938                 ASSERT(log_offset <= iclog->ic_size - 1);
1939                 ptr = iclog->ic_datap + log_offset;
1940
1941                 /* start_lsn is the first lsn written to. That's all we need. */
1942                 if (!*start_lsn)
1943                         *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
1944
1945                 /*
1946                  * This loop writes out as many regions as can fit in the amount
1947                  * of space which was allocated by xlog_state_get_iclog_space().
1948                  */
1949                 while (lv && index < lv->lv_niovecs) {
1950                         struct xfs_log_iovec    *reg = &vecp[index];
1951                         struct xlog_op_header   *ophdr;
1952                         int                     start_rec_copy;
1953                         int                     copy_len;
1954                         int                     copy_off;
1955
1956                         ASSERT(reg->i_len % sizeof(__int32_t) == 0);
1957                         ASSERT((unsigned long)ptr % sizeof(__int32_t) == 0);
1958
1959                         start_rec_copy = xlog_write_start_rec(ptr, ticket);
1960                         if (start_rec_copy) {
1961                                 record_cnt++;
1962                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
1963                                                    start_rec_copy);
1964                         }
1965
1966                         ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
1967                         if (!ophdr)
1968                                 return XFS_ERROR(EIO);
1969
1970                         xlog_write_adv_cnt(&ptr, &len, &log_offset,
1971                                            sizeof(struct xlog_op_header));
1972
1973                         len += xlog_write_setup_copy(ticket, ophdr,
1974                                                      iclog->ic_size-log_offset,
1975                                                      reg->i_len,
1976                                                      &copy_off, &copy_len,
1977                                                      &partial_copy,
1978                                                      &partial_copy_len);
1979                         xlog_verify_dest_ptr(log, ptr);
1980
1981                         /* copy region */
1982                         ASSERT(copy_len >= 0);
1983                         memcpy(ptr, reg->i_addr + copy_off, copy_len);
1984                         xlog_write_adv_cnt(&ptr, &len, &log_offset, copy_len);
1985
1986                         copy_len += start_rec_copy + sizeof(xlog_op_header_t);
1987                         record_cnt++;
1988                         data_cnt += contwr ? copy_len : 0;
1989
1990                         error = xlog_write_copy_finish(log, iclog, flags,
1991                                                        &record_cnt, &data_cnt,
1992                                                        &partial_copy,
1993                                                        &partial_copy_len,
1994                                                        log_offset,
1995                                                        commit_iclog);
1996                         if (error)
1997                                 return error;
1998
1999                         /*
2000                          * if we had a partial copy, we need to get more iclog
2001                          * space but we don't want to increment the region
2002                          * index because there is still more is this region to
2003                          * write.
2004                          *
2005                          * If we completed writing this region, and we flushed
2006                          * the iclog (indicated by resetting of the record
2007                          * count), then we also need to get more log space. If
2008                          * this was the last record, though, we are done and
2009                          * can just return.
2010                          */
2011                         if (partial_copy)
2012                                 break;
2013
2014                         if (++index == lv->lv_niovecs) {
2015                                 lv = lv->lv_next;
2016                                 index = 0;
2017                                 if (lv)
2018                                         vecp = lv->lv_iovecp;
2019                         }
2020                         if (record_cnt == 0) {
2021                                 if (!lv)
2022                                         return 0;
2023                                 break;
2024                         }
2025                 }
2026         }
2027
2028         ASSERT(len == 0);
2029
2030         xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2031         if (!commit_iclog)
2032                 return xlog_state_release_iclog(log, iclog);
2033
2034         ASSERT(flags & XLOG_COMMIT_TRANS);
2035         *commit_iclog = iclog;
2036         return 0;
2037 }
2038
2039
2040 /*****************************************************************************
2041  *
2042  *              State Machine functions
2043  *
2044  *****************************************************************************
2045  */
2046
2047 /* Clean iclogs starting from the head.  This ordering must be
2048  * maintained, so an iclog doesn't become ACTIVE beyond one that
2049  * is SYNCING.  This is also required to maintain the notion that we use
2050  * a ordered wait queue to hold off would be writers to the log when every
2051  * iclog is trying to sync to disk.
2052  *
2053  * State Change: DIRTY -> ACTIVE
2054  */
2055 STATIC void
2056 xlog_state_clean_log(xlog_t *log)
2057 {
2058         xlog_in_core_t  *iclog;
2059         int changed = 0;
2060
2061         iclog = log->l_iclog;
2062         do {
2063                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
2064                         iclog->ic_state = XLOG_STATE_ACTIVE;
2065                         iclog->ic_offset       = 0;
2066                         ASSERT(iclog->ic_callback == NULL);
2067                         /*
2068                          * If the number of ops in this iclog indicate it just
2069                          * contains the dummy transaction, we can
2070                          * change state into IDLE (the second time around).
2071                          * Otherwise we should change the state into
2072                          * NEED a dummy.
2073                          * We don't need to cover the dummy.
2074                          */
2075                         if (!changed &&
2076                            (be32_to_cpu(iclog->ic_header.h_num_logops) ==
2077                                         XLOG_COVER_OPS)) {
2078                                 changed = 1;
2079                         } else {
2080                                 /*
2081                                  * We have two dirty iclogs so start over
2082                                  * This could also be num of ops indicates
2083                                  * this is not the dummy going out.
2084                                  */
2085                                 changed = 2;
2086                         }
2087                         iclog->ic_header.h_num_logops = 0;
2088                         memset(iclog->ic_header.h_cycle_data, 0,
2089                               sizeof(iclog->ic_header.h_cycle_data));
2090                         iclog->ic_header.h_lsn = 0;
2091                 } else if (iclog->ic_state == XLOG_STATE_ACTIVE)
2092                         /* do nothing */;
2093                 else
2094                         break;  /* stop cleaning */
2095                 iclog = iclog->ic_next;
2096         } while (iclog != log->l_iclog);
2097
2098         /* log is locked when we are called */
2099         /*
2100          * Change state for the dummy log recording.
2101          * We usually go to NEED. But we go to NEED2 if the changed indicates
2102          * we are done writing the dummy record.
2103          * If we are done with the second dummy recored (DONE2), then
2104          * we go to IDLE.
2105          */
2106         if (changed) {
2107                 switch (log->l_covered_state) {
2108                 case XLOG_STATE_COVER_IDLE:
2109                 case XLOG_STATE_COVER_NEED:
2110                 case XLOG_STATE_COVER_NEED2:
2111                         log->l_covered_state = XLOG_STATE_COVER_NEED;
2112                         break;
2113
2114                 case XLOG_STATE_COVER_DONE:
2115                         if (changed == 1)
2116                                 log->l_covered_state = XLOG_STATE_COVER_NEED2;
2117                         else
2118                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2119                         break;
2120
2121                 case XLOG_STATE_COVER_DONE2:
2122                         if (changed == 1)
2123                                 log->l_covered_state = XLOG_STATE_COVER_IDLE;
2124                         else
2125                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2126                         break;
2127
2128                 default:
2129                         ASSERT(0);
2130                 }
2131         }
2132 }       /* xlog_state_clean_log */
2133
2134 STATIC xfs_lsn_t
2135 xlog_get_lowest_lsn(
2136         xlog_t          *log)
2137 {
2138         xlog_in_core_t  *lsn_log;
2139         xfs_lsn_t       lowest_lsn, lsn;
2140
2141         lsn_log = log->l_iclog;
2142         lowest_lsn = 0;
2143         do {
2144             if (!(lsn_log->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY))) {
2145                 lsn = be64_to_cpu(lsn_log->ic_header.h_lsn);
2146                 if ((lsn && !lowest_lsn) ||
2147                     (XFS_LSN_CMP(lsn, lowest_lsn) < 0)) {
2148                         lowest_lsn = lsn;
2149                 }
2150             }
2151             lsn_log = lsn_log->ic_next;
2152         } while (lsn_log != log->l_iclog);
2153         return lowest_lsn;
2154 }
2155
2156
2157 STATIC void
2158 xlog_state_do_callback(
2159         xlog_t          *log,
2160         int             aborted,
2161         xlog_in_core_t  *ciclog)
2162 {
2163         xlog_in_core_t     *iclog;
2164         xlog_in_core_t     *first_iclog;        /* used to know when we've
2165                                                  * processed all iclogs once */
2166         xfs_log_callback_t *cb, *cb_next;
2167         int                flushcnt = 0;
2168         xfs_lsn_t          lowest_lsn;
2169         int                ioerrors;    /* counter: iclogs with errors */
2170         int                loopdidcallbacks; /* flag: inner loop did callbacks*/
2171         int                funcdidcallbacks; /* flag: function did callbacks */
2172         int                repeats;     /* for issuing console warnings if
2173                                          * looping too many times */
2174         int                wake = 0;
2175
2176         spin_lock(&log->l_icloglock);
2177         first_iclog = iclog = log->l_iclog;
2178         ioerrors = 0;
2179         funcdidcallbacks = 0;
2180         repeats = 0;
2181
2182         do {
2183                 /*
2184                  * Scan all iclogs starting with the one pointed to by the
2185                  * log.  Reset this starting point each time the log is
2186                  * unlocked (during callbacks).
2187                  *
2188                  * Keep looping through iclogs until one full pass is made
2189                  * without running any callbacks.
2190                  */
2191                 first_iclog = log->l_iclog;
2192                 iclog = log->l_iclog;
2193                 loopdidcallbacks = 0;
2194                 repeats++;
2195
2196                 do {
2197
2198                         /* skip all iclogs in the ACTIVE & DIRTY states */
2199                         if (iclog->ic_state &
2200                             (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
2201                                 iclog = iclog->ic_next;
2202                                 continue;
2203                         }
2204
2205                         /*
2206                          * Between marking a filesystem SHUTDOWN and stopping
2207                          * the log, we do flush all iclogs to disk (if there
2208                          * wasn't a log I/O error). So, we do want things to
2209                          * go smoothly in case of just a SHUTDOWN  w/o a
2210                          * LOG_IO_ERROR.
2211                          */
2212                         if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
2213                                 /*
2214                                  * Can only perform callbacks in order.  Since
2215                                  * this iclog is not in the DONE_SYNC/
2216                                  * DO_CALLBACK state, we skip the rest and
2217                                  * just try to clean up.  If we set our iclog
2218                                  * to DO_CALLBACK, we will not process it when
2219                                  * we retry since a previous iclog is in the
2220                                  * CALLBACK and the state cannot change since
2221                                  * we are holding the l_icloglock.
2222                                  */
2223                                 if (!(iclog->ic_state &
2224                                         (XLOG_STATE_DONE_SYNC |
2225                                                  XLOG_STATE_DO_CALLBACK))) {
2226                                         if (ciclog && (ciclog->ic_state ==
2227                                                         XLOG_STATE_DONE_SYNC)) {
2228                                                 ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
2229                                         }
2230                                         break;
2231                                 }
2232                                 /*
2233                                  * We now have an iclog that is in either the
2234                                  * DO_CALLBACK or DONE_SYNC states. The other
2235                                  * states (WANT_SYNC, SYNCING, or CALLBACK were
2236                                  * caught by the above if and are going to
2237                                  * clean (i.e. we aren't doing their callbacks)
2238                                  * see the above if.
2239                                  */
2240
2241                                 /*
2242                                  * We will do one more check here to see if we
2243                                  * have chased our tail around.
2244                                  */
2245
2246                                 lowest_lsn = xlog_get_lowest_lsn(log);
2247                                 if (lowest_lsn &&
2248                                     XFS_LSN_CMP(lowest_lsn,
2249                                                 be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
2250                                         iclog = iclog->ic_next;
2251                                         continue; /* Leave this iclog for
2252                                                    * another thread */
2253                                 }
2254
2255                                 iclog->ic_state = XLOG_STATE_CALLBACK;
2256
2257                                 spin_unlock(&log->l_icloglock);
2258
2259                                 /* l_last_sync_lsn field protected by
2260                                  * l_grant_lock. Don't worry about iclog's lsn.
2261                                  * No one else can be here except us.
2262                                  */
2263                                 spin_lock(&log->l_grant_lock);
2264                                 ASSERT(XFS_LSN_CMP(log->l_last_sync_lsn,
2265                                        be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
2266                                 log->l_last_sync_lsn =
2267                                         be64_to_cpu(iclog->ic_header.h_lsn);
2268                                 spin_unlock(&log->l_grant_lock);
2269
2270                         } else {
2271                                 spin_unlock(&log->l_icloglock);
2272                                 ioerrors++;
2273                         }
2274
2275                         /*
2276                          * Keep processing entries in the callback list until
2277                          * we come around and it is empty.  We need to
2278                          * atomically see that the list is empty and change the
2279                          * state to DIRTY so that we don't miss any more
2280                          * callbacks being added.
2281                          */
2282                         spin_lock(&iclog->ic_callback_lock);
2283                         cb = iclog->ic_callback;
2284                         while (cb) {
2285                                 iclog->ic_callback_tail = &(iclog->ic_callback);
2286                                 iclog->ic_callback = NULL;
2287                                 spin_unlock(&iclog->ic_callback_lock);
2288
2289                                 /* perform callbacks in the order given */
2290                                 for (; cb; cb = cb_next) {
2291                                         cb_next = cb->cb_next;
2292                                         cb->cb_func(cb->cb_arg, aborted);
2293                                 }
2294                                 spin_lock(&iclog->ic_callback_lock);
2295                                 cb = iclog->ic_callback;
2296                         }
2297
2298                         loopdidcallbacks++;
2299                         funcdidcallbacks++;
2300
2301                         spin_lock(&log->l_icloglock);
2302                         ASSERT(iclog->ic_callback == NULL);
2303                         spin_unlock(&iclog->ic_callback_lock);
2304                         if (!(iclog->ic_state & XLOG_STATE_IOERROR))
2305                                 iclog->ic_state = XLOG_STATE_DIRTY;
2306
2307                         /*
2308                          * Transition from DIRTY to ACTIVE if applicable.
2309                          * NOP if STATE_IOERROR.
2310                          */
2311                         xlog_state_clean_log(log);
2312
2313                         /* wake up threads waiting in xfs_log_force() */
2314                         sv_broadcast(&iclog->ic_force_wait);
2315
2316                         iclog = iclog->ic_next;
2317                 } while (first_iclog != iclog);
2318
2319                 if (repeats > 5000) {
2320                         flushcnt += repeats;
2321                         repeats = 0;
2322                         xfs_fs_cmn_err(CE_WARN, log->l_mp,
2323                                 "%s: possible infinite loop (%d iterations)",
2324                                 __func__, flushcnt);
2325                 }
2326         } while (!ioerrors && loopdidcallbacks);
2327
2328         /*
2329          * make one last gasp attempt to see if iclogs are being left in
2330          * limbo..
2331          */
2332 #ifdef DEBUG
2333         if (funcdidcallbacks) {
2334                 first_iclog = iclog = log->l_iclog;
2335                 do {
2336                         ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
2337                         /*
2338                          * Terminate the loop if iclogs are found in states
2339                          * which will cause other threads to clean up iclogs.
2340                          *
2341                          * SYNCING - i/o completion will go through logs
2342                          * DONE_SYNC - interrupt thread should be waiting for
2343                          *              l_icloglock
2344                          * IOERROR - give up hope all ye who enter here
2345                          */
2346                         if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2347                             iclog->ic_state == XLOG_STATE_SYNCING ||
2348                             iclog->ic_state == XLOG_STATE_DONE_SYNC ||
2349                             iclog->ic_state == XLOG_STATE_IOERROR )
2350                                 break;
2351                         iclog = iclog->ic_next;
2352                 } while (first_iclog != iclog);
2353         }
2354 #endif
2355
2356         if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
2357                 wake = 1;
2358         spin_unlock(&log->l_icloglock);
2359
2360         if (wake)
2361                 sv_broadcast(&log->l_flush_wait);
2362 }
2363
2364
2365 /*
2366  * Finish transitioning this iclog to the dirty state.
2367  *
2368  * Make sure that we completely execute this routine only when this is
2369  * the last call to the iclog.  There is a good chance that iclog flushes,
2370  * when we reach the end of the physical log, get turned into 2 separate
2371  * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2372  * routine.  By using the reference count bwritecnt, we guarantee that only
2373  * the second completion goes through.
2374  *
2375  * Callbacks could take time, so they are done outside the scope of the
2376  * global state machine log lock.
2377  */
2378 STATIC void
2379 xlog_state_done_syncing(
2380         xlog_in_core_t  *iclog,
2381         int             aborted)
2382 {
2383         xlog_t             *log = iclog->ic_log;
2384
2385         spin_lock(&log->l_icloglock);
2386
2387         ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
2388                iclog->ic_state == XLOG_STATE_IOERROR);
2389         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2390         ASSERT(iclog->ic_bwritecnt == 1 || iclog->ic_bwritecnt == 2);
2391
2392
2393         /*
2394          * If we got an error, either on the first buffer, or in the case of
2395          * split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
2396          * and none should ever be attempted to be written to disk
2397          * again.
2398          */
2399         if (iclog->ic_state != XLOG_STATE_IOERROR) {
2400                 if (--iclog->ic_bwritecnt == 1) {
2401                         spin_unlock(&log->l_icloglock);
2402                         return;
2403                 }
2404                 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2405         }
2406
2407         /*
2408          * Someone could be sleeping prior to writing out the next
2409          * iclog buffer, we wake them all, one will get to do the
2410          * I/O, the others get to wait for the result.
2411          */
2412         sv_broadcast(&iclog->ic_write_wait);
2413         spin_unlock(&log->l_icloglock);
2414         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
2415 }       /* xlog_state_done_syncing */
2416
2417
2418 /*
2419  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2420  * sleep.  We wait on the flush queue on the head iclog as that should be
2421  * the first iclog to complete flushing. Hence if all iclogs are syncing,
2422  * we will wait here and all new writes will sleep until a sync completes.
2423  *
2424  * The in-core logs are used in a circular fashion. They are not used
2425  * out-of-order even when an iclog past the head is free.
2426  *
2427  * return:
2428  *      * log_offset where xlog_write() can start writing into the in-core
2429  *              log's data space.
2430  *      * in-core log pointer to which xlog_write() should write.
2431  *      * boolean indicating this is a continued write to an in-core log.
2432  *              If this is the last write, then the in-core log's offset field
2433  *              needs to be incremented, depending on the amount of data which
2434  *              is copied.
2435  */
2436 STATIC int
2437 xlog_state_get_iclog_space(xlog_t         *log,
2438                            int            len,
2439                            xlog_in_core_t **iclogp,
2440                            xlog_ticket_t  *ticket,
2441                            int            *continued_write,
2442                            int            *logoffsetp)
2443 {
2444         int               log_offset;
2445         xlog_rec_header_t *head;
2446         xlog_in_core_t    *iclog;
2447         int               error;
2448
2449 restart:
2450         spin_lock(&log->l_icloglock);
2451         if (XLOG_FORCED_SHUTDOWN(log)) {
2452                 spin_unlock(&log->l_icloglock);
2453                 return XFS_ERROR(EIO);
2454         }
2455
2456         iclog = log->l_iclog;
2457         if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2458                 XFS_STATS_INC(xs_log_noiclogs);
2459
2460                 /* Wait for log writes to have flushed */
2461                 sv_wait(&log->l_flush_wait, 0, &log->l_icloglock, 0);
2462                 goto restart;
2463         }
2464
2465         head = &iclog->ic_header;
2466
2467         atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2468         log_offset = iclog->ic_offset;
2469
2470         /* On the 1st write to an iclog, figure out lsn.  This works
2471          * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2472          * committing to.  If the offset is set, that's how many blocks
2473          * must be written.
2474          */
2475         if (log_offset == 0) {
2476                 ticket->t_curr_res -= log->l_iclog_hsize;
2477                 xlog_tic_add_region(ticket,
2478                                     log->l_iclog_hsize,
2479                                     XLOG_REG_TYPE_LRHEADER);
2480                 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2481                 head->h_lsn = cpu_to_be64(
2482                         xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2483                 ASSERT(log->l_curr_block >= 0);
2484         }
2485
2486         /* If there is enough room to write everything, then do it.  Otherwise,
2487          * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2488          * bit is on, so this will get flushed out.  Don't update ic_offset
2489          * until you know exactly how many bytes get copied.  Therefore, wait
2490          * until later to update ic_offset.
2491          *
2492          * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2493          * can fit into remaining data section.
2494          */
2495         if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2496                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2497
2498                 /*
2499                  * If I'm the only one writing to this iclog, sync it to disk.
2500                  * We need to do an atomic compare and decrement here to avoid
2501                  * racing with concurrent atomic_dec_and_lock() calls in
2502                  * xlog_state_release_iclog() when there is more than one
2503                  * reference to the iclog.
2504                  */
2505                 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
2506                         /* we are the only one */
2507                         spin_unlock(&log->l_icloglock);
2508                         error = xlog_state_release_iclog(log, iclog);
2509                         if (error)
2510                                 return error;
2511                 } else {
2512                         spin_unlock(&log->l_icloglock);
2513                 }
2514                 goto restart;
2515         }
2516
2517         /* Do we have enough room to write the full amount in the remainder
2518          * of this iclog?  Or must we continue a write on the next iclog and
2519          * mark this iclog as completely taken?  In the case where we switch
2520          * iclogs (to mark it taken), this particular iclog will release/sync
2521          * to disk in xlog_write().
2522          */
2523         if (len <= iclog->ic_size - iclog->ic_offset) {
2524                 *continued_write = 0;
2525                 iclog->ic_offset += len;
2526         } else {
2527                 *continued_write = 1;
2528                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2529         }
2530         *iclogp = iclog;
2531
2532         ASSERT(iclog->ic_offset <= iclog->ic_size);
2533         spin_unlock(&log->l_icloglock);
2534
2535         *logoffsetp = log_offset;
2536         return 0;
2537 }       /* xlog_state_get_iclog_space */
2538
2539 /*
2540  * Atomically get the log space required for a log ticket.
2541  *
2542  * Once a ticket gets put onto the reserveq, it will only return after
2543  * the needed reservation is satisfied.
2544  */
2545 STATIC int
2546 xlog_grant_log_space(xlog_t        *log,
2547                      xlog_ticket_t *tic)
2548 {
2549         int              free_bytes;
2550         int              need_bytes;
2551 #ifdef DEBUG
2552         xfs_lsn_t        tail_lsn;
2553 #endif
2554
2555
2556 #ifdef DEBUG
2557         if (log->l_flags & XLOG_ACTIVE_RECOVERY)
2558                 panic("grant Recovery problem");
2559 #endif
2560
2561         /* Is there space or do we need to sleep? */
2562         spin_lock(&log->l_grant_lock);
2563
2564         trace_xfs_log_grant_enter(log, tic);
2565
2566         /* something is already sleeping; insert new transaction at end */
2567         if (log->l_reserve_headq) {
2568                 xlog_ins_ticketq(&log->l_reserve_headq, tic);
2569
2570                 trace_xfs_log_grant_sleep1(log, tic);
2571
2572                 /*
2573                  * Gotta check this before going to sleep, while we're
2574                  * holding the grant lock.
2575                  */
2576                 if (XLOG_FORCED_SHUTDOWN(log))
2577                         goto error_return;
2578
2579                 XFS_STATS_INC(xs_sleep_logspace);
2580                 sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
2581                 /*
2582                  * If we got an error, and the filesystem is shutting down,
2583                  * we'll catch it down below. So just continue...
2584                  */
2585                 trace_xfs_log_grant_wake1(log, tic);
2586                 spin_lock(&log->l_grant_lock);
2587         }
2588         if (tic->t_flags & XFS_LOG_PERM_RESERV)
2589                 need_bytes = tic->t_unit_res*tic->t_ocnt;
2590         else
2591                 need_bytes = tic->t_unit_res;
2592
2593 redo:
2594         if (XLOG_FORCED_SHUTDOWN(log))
2595                 goto error_return;
2596
2597         free_bytes = xlog_space_left(log, log->l_grant_reserve_cycle,
2598                                      log->l_grant_reserve_bytes);
2599         if (free_bytes < need_bytes) {
2600                 if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
2601                         xlog_ins_ticketq(&log->l_reserve_headq, tic);
2602
2603                 trace_xfs_log_grant_sleep2(log, tic);
2604
2605                 spin_unlock(&log->l_grant_lock);
2606                 xlog_grant_push_ail(log->l_mp, need_bytes);
2607                 spin_lock(&log->l_grant_lock);
2608
2609                 XFS_STATS_INC(xs_sleep_logspace);
2610                 sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
2611
2612                 spin_lock(&log->l_grant_lock);
2613                 if (XLOG_FORCED_SHUTDOWN(log))
2614                         goto error_return;
2615
2616                 trace_xfs_log_grant_wake2(log, tic);
2617
2618                 goto redo;
2619         } else if (tic->t_flags & XLOG_TIC_IN_Q)
2620                 xlog_del_ticketq(&log->l_reserve_headq, tic);
2621
2622         /* we've got enough space */
2623         xlog_grant_add_space(log, need_bytes);
2624 #ifdef DEBUG
2625         tail_lsn = log->l_tail_lsn;
2626         /*
2627          * Check to make sure the grant write head didn't just over lap the
2628          * tail.  If the cycles are the same, we can't be overlapping.
2629          * Otherwise, make sure that the cycles differ by exactly one and
2630          * check the byte count.
2631          */
2632         if (CYCLE_LSN(tail_lsn) != log->l_grant_write_cycle) {
2633                 ASSERT(log->l_grant_write_cycle-1 == CYCLE_LSN(tail_lsn));
2634                 ASSERT(log->l_grant_write_bytes <= BBTOB(BLOCK_LSN(tail_lsn)));
2635         }
2636 #endif
2637         trace_xfs_log_grant_exit(log, tic);
2638         xlog_verify_grant_head(log, 1);
2639         spin_unlock(&log->l_grant_lock);
2640         return 0;
2641
2642  error_return:
2643         if (tic->t_flags & XLOG_TIC_IN_Q)
2644                 xlog_del_ticketq(&log->l_reserve_headq, tic);
2645
2646         trace_xfs_log_grant_error(log, tic);
2647
2648         /*
2649          * If we are failing, make sure the ticket doesn't have any
2650          * current reservations. We don't want to add this back when
2651          * the ticket/transaction gets cancelled.
2652          */
2653         tic->t_curr_res = 0;
2654         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
2655         spin_unlock(&log->l_grant_lock);
2656         return XFS_ERROR(EIO);
2657 }       /* xlog_grant_log_space */
2658
2659
2660 /*
2661  * Replenish the byte reservation required by moving the grant write head.
2662  *
2663  *
2664  */
2665 STATIC int
2666 xlog_regrant_write_log_space(xlog_t        *log,
2667                              xlog_ticket_t *tic)
2668 {
2669         int             free_bytes, need_bytes;
2670         xlog_ticket_t   *ntic;
2671 #ifdef DEBUG
2672         xfs_lsn_t       tail_lsn;
2673 #endif
2674
2675         tic->t_curr_res = tic->t_unit_res;
2676         xlog_tic_reset_res(tic);
2677
2678         if (tic->t_cnt > 0)
2679                 return 0;
2680
2681 #ifdef DEBUG
2682         if (log->l_flags & XLOG_ACTIVE_RECOVERY)
2683                 panic("regrant Recovery problem");
2684 #endif
2685
2686         spin_lock(&log->l_grant_lock);
2687
2688         trace_xfs_log_regrant_write_enter(log, tic);
2689
2690         if (XLOG_FORCED_SHUTDOWN(log))
2691                 goto error_return;
2692
2693         /* If there are other waiters on the queue then give them a
2694          * chance at logspace before us. Wake up the first waiters,
2695          * if we do not wake up all the waiters then go to sleep waiting
2696          * for more free space, otherwise try to get some space for
2697          * this transaction.
2698          */
2699         need_bytes = tic->t_unit_res;
2700         if ((ntic = log->l_write_headq)) {
2701                 free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
2702                                              log->l_grant_write_bytes);
2703                 do {
2704                         ASSERT(ntic->t_flags & XLOG_TIC_PERM_RESERV);
2705
2706                         if (free_bytes < ntic->t_unit_res)
2707                                 break;
2708                         free_bytes -= ntic->t_unit_res;
2709                         sv_signal(&ntic->t_wait);
2710                         ntic = ntic->t_next;
2711                 } while (ntic != log->l_write_headq);
2712
2713                 if (ntic != log->l_write_headq) {
2714                         if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
2715                                 xlog_ins_ticketq(&log->l_write_headq, tic);
2716
2717                         trace_xfs_log_regrant_write_sleep1(log, tic);
2718
2719                         spin_unlock(&log->l_grant_lock);
2720                         xlog_grant_push_ail(log->l_mp, need_bytes);
2721                         spin_lock(&log->l_grant_lock);
2722
2723                         XFS_STATS_INC(xs_sleep_logspace);
2724                         sv_wait(&tic->t_wait, PINOD|PLTWAIT,
2725                                 &log->l_grant_lock, s);
2726
2727                         /* If we're shutting down, this tic is already
2728                          * off the queue */
2729                         spin_lock(&log->l_grant_lock);
2730                         if (XLOG_FORCED_SHUTDOWN(log))
2731                                 goto error_return;
2732
2733                         trace_xfs_log_regrant_write_wake1(log, tic);
2734                 }
2735         }
2736
2737 redo:
2738         if (XLOG_FORCED_SHUTDOWN(log))
2739                 goto error_return;
2740
2741         free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
2742                                      log->l_grant_write_bytes);
2743         if (free_bytes < need_bytes) {
2744                 if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
2745                         xlog_ins_ticketq(&log->l_write_headq, tic);
2746                 spin_unlock(&log->l_grant_lock);
2747                 xlog_grant_push_ail(log->l_mp, need_bytes);
2748                 spin_lock(&log->l_grant_lock);
2749
2750                 XFS_STATS_INC(xs_sleep_logspace);
2751                 trace_xfs_log_regrant_write_sleep2(log, tic);
2752
2753                 sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
2754
2755                 /* If we're shutting down, this tic is already off the queue */
2756                 spin_lock(&log->l_grant_lock);
2757                 if (XLOG_FORCED_SHUTDOWN(log))
2758                         goto error_return;
2759
2760                 trace_xfs_log_regrant_write_wake2(log, tic);
2761                 goto redo;
2762         } else if (tic->t_flags & XLOG_TIC_IN_Q)
2763                 xlog_del_ticketq(&log->l_write_headq, tic);
2764
2765         /* we've got enough space */
2766         xlog_grant_add_space_write(log, need_bytes);
2767 #ifdef DEBUG
2768         tail_lsn = log->l_tail_lsn;
2769         if (CYCLE_LSN(tail_lsn) != log->l_grant_write_cycle) {
2770                 ASSERT(log->l_grant_write_cycle-1 == CYCLE_LSN(tail_lsn));
2771                 ASSERT(log->l_grant_write_bytes <= BBTOB(BLOCK_LSN(tail_lsn)));
2772         }
2773 #endif
2774
2775         trace_xfs_log_regrant_write_exit(log, tic);
2776
2777         xlog_verify_grant_head(log, 1);
2778         spin_unlock(&log->l_grant_lock);
2779         return 0;
2780
2781
2782  error_return:
2783         if (tic->t_flags & XLOG_TIC_IN_Q)
2784                 xlog_del_ticketq(&log->l_reserve_headq, tic);
2785
2786         trace_xfs_log_regrant_write_error(log, tic);
2787
2788         /*
2789          * If we are failing, make sure the ticket doesn't have any
2790          * current reservations. We don't want to add this back when
2791          * the ticket/transaction gets cancelled.
2792          */
2793         tic->t_curr_res = 0;
2794         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
2795         spin_unlock(&log->l_grant_lock);
2796         return XFS_ERROR(EIO);
2797 }       /* xlog_regrant_write_log_space */
2798
2799
2800 /* The first cnt-1 times through here we don't need to
2801  * move the grant write head because the permanent
2802  * reservation has reserved cnt times the unit amount.
2803  * Release part of current permanent unit reservation and
2804  * reset current reservation to be one units worth.  Also
2805  * move grant reservation head forward.
2806  */
2807 STATIC void
2808 xlog_regrant_reserve_log_space(xlog_t        *log,
2809                                xlog_ticket_t *ticket)
2810 {
2811         trace_xfs_log_regrant_reserve_enter(log, ticket);
2812
2813         if (ticket->t_cnt > 0)
2814                 ticket->t_cnt--;
2815
2816         spin_lock(&log->l_grant_lock);
2817         xlog_grant_sub_space(log, ticket->t_curr_res);
2818         ticket->t_curr_res = ticket->t_unit_res;
2819         xlog_tic_reset_res(ticket);
2820
2821         trace_xfs_log_regrant_reserve_sub(log, ticket);
2822
2823         xlog_verify_grant_head(log, 1);
2824
2825         /* just return if we still have some of the pre-reserved space */
2826         if (ticket->t_cnt > 0) {
2827                 spin_unlock(&log->l_grant_lock);
2828                 return;
2829         }
2830
2831         xlog_grant_add_space_reserve(log, ticket->t_unit_res);
2832
2833         trace_xfs_log_regrant_reserve_exit(log, ticket);
2834
2835         xlog_verify_grant_head(log, 0);
2836         spin_unlock(&log->l_grant_lock);
2837         ticket->t_curr_res = ticket->t_unit_res;
2838         xlog_tic_reset_res(ticket);
2839 }       /* xlog_regrant_reserve_log_space */
2840
2841
2842 /*
2843  * Give back the space left from a reservation.
2844  *
2845  * All the information we need to make a correct determination of space left
2846  * is present.  For non-permanent reservations, things are quite easy.  The
2847  * count should have been decremented to zero.  We only need to deal with the
2848  * space remaining in the current reservation part of the ticket.  If the
2849  * ticket contains a permanent reservation, there may be left over space which
2850  * needs to be released.  A count of N means that N-1 refills of the current
2851  * reservation can be done before we need to ask for more space.  The first
2852  * one goes to fill up the first current reservation.  Once we run out of
2853  * space, the count will stay at zero and the only space remaining will be
2854  * in the current reservation field.
2855  */
2856 STATIC void
2857 xlog_ungrant_log_space(xlog_t        *log,
2858                        xlog_ticket_t *ticket)
2859 {
2860         if (ticket->t_cnt > 0)
2861                 ticket->t_cnt--;
2862
2863         spin_lock(&log->l_grant_lock);
2864         trace_xfs_log_ungrant_enter(log, ticket);
2865
2866         xlog_grant_sub_space(log, ticket->t_curr_res);
2867
2868         trace_xfs_log_ungrant_sub(log, ticket);
2869
2870         /* If this is a permanent reservation ticket, we may be able to free
2871          * up more space based on the remaining count.
2872          */
2873         if (ticket->t_cnt > 0) {
2874                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
2875                 xlog_grant_sub_space(log, ticket->t_unit_res*ticket->t_cnt);
2876         }
2877
2878         trace_xfs_log_ungrant_exit(log, ticket);
2879
2880         xlog_verify_grant_head(log, 1);
2881         spin_unlock(&log->l_grant_lock);
2882         xfs_log_move_tail(log->l_mp, 1);
2883 }       /* xlog_ungrant_log_space */
2884
2885
2886 /*
2887  * Flush iclog to disk if this is the last reference to the given iclog and
2888  * the WANT_SYNC bit is set.
2889  *
2890  * When this function is entered, the iclog is not necessarily in the
2891  * WANT_SYNC state.  It may be sitting around waiting to get filled.
2892  *
2893  *
2894  */
2895 STATIC int
2896 xlog_state_release_iclog(
2897         xlog_t          *log,
2898         xlog_in_core_t  *iclog)
2899 {
2900         int             sync = 0;       /* do we sync? */
2901
2902         if (iclog->ic_state & XLOG_STATE_IOERROR)
2903                 return XFS_ERROR(EIO);
2904
2905         ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
2906         if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
2907                 return 0;
2908
2909         if (iclog->ic_state & XLOG_STATE_IOERROR) {
2910                 spin_unlock(&log->l_icloglock);
2911                 return XFS_ERROR(EIO);
2912         }
2913         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
2914                iclog->ic_state == XLOG_STATE_WANT_SYNC);
2915
2916         if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
2917                 /* update tail before writing to iclog */
2918                 xlog_assign_tail_lsn(log->l_mp);
2919                 sync++;
2920                 iclog->ic_state = XLOG_STATE_SYNCING;
2921                 iclog->ic_header.h_tail_lsn = cpu_to_be64(log->l_tail_lsn);
2922                 xlog_verify_tail_lsn(log, iclog, log->l_tail_lsn);
2923                 /* cycle incremented when incrementing curr_block */
2924         }
2925         spin_unlock(&log->l_icloglock);
2926
2927         /*
2928          * We let the log lock go, so it's possible that we hit a log I/O
2929          * error or some other SHUTDOWN condition that marks the iclog
2930          * as XLOG_STATE_IOERROR before the bwrite. However, we know that
2931          * this iclog has consistent data, so we ignore IOERROR
2932          * flags after this point.
2933          */
2934         if (sync)
2935                 return xlog_sync(log, iclog);
2936         return 0;
2937 }       /* xlog_state_release_iclog */
2938
2939
2940 /*
2941  * This routine will mark the current iclog in the ring as WANT_SYNC
2942  * and move the current iclog pointer to the next iclog in the ring.
2943  * When this routine is called from xlog_state_get_iclog_space(), the
2944  * exact size of the iclog has not yet been determined.  All we know is
2945  * that every data block.  We have run out of space in this log record.
2946  */
2947 STATIC void
2948 xlog_state_switch_iclogs(xlog_t         *log,
2949                          xlog_in_core_t *iclog,
2950                          int            eventual_size)
2951 {
2952         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
2953         if (!eventual_size)
2954                 eventual_size = iclog->ic_offset;
2955         iclog->ic_state = XLOG_STATE_WANT_SYNC;
2956         iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
2957         log->l_prev_block = log->l_curr_block;
2958         log->l_prev_cycle = log->l_curr_cycle;
2959
2960         /* roll log?: ic_offset changed later */
2961         log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
2962
2963         /* Round up to next log-sunit */
2964         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
2965             log->l_mp->m_sb.sb_logsunit > 1) {
2966                 __uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
2967                 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
2968         }
2969
2970         if (log->l_curr_block >= log->l_logBBsize) {
2971                 log->l_curr_cycle++;
2972                 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
2973                         log->l_curr_cycle++;
2974                 log->l_curr_block -= log->l_logBBsize;
2975                 ASSERT(log->l_curr_block >= 0);
2976         }
2977         ASSERT(iclog == log->l_iclog);
2978         log->l_iclog = iclog->ic_next;
2979 }       /* xlog_state_switch_iclogs */
2980
2981 /*
2982  * Write out all data in the in-core log as of this exact moment in time.
2983  *
2984  * Data may be written to the in-core log during this call.  However,
2985  * we don't guarantee this data will be written out.  A change from past
2986  * implementation means this routine will *not* write out zero length LRs.
2987  *
2988  * Basically, we try and perform an intelligent scan of the in-core logs.
2989  * If we determine there is no flushable data, we just return.  There is no
2990  * flushable data if:
2991  *
2992  *      1. the current iclog is active and has no data; the previous iclog
2993  *              is in the active or dirty state.
2994  *      2. the current iclog is drity, and the previous iclog is in the
2995  *              active or dirty state.
2996  *
2997  * We may sleep if:
2998  *
2999  *      1. the current iclog is not in the active nor dirty state.
3000  *      2. the current iclog dirty, and the previous iclog is not in the
3001  *              active nor dirty state.
3002  *      3. the current iclog is active, and there is another thread writing
3003  *              to this particular iclog.
3004  *      4. a) the current iclog is active and has no other writers
3005  *         b) when we return from flushing out this iclog, it is still
3006  *              not in the active nor dirty state.
3007  */
3008 int
3009 _xfs_log_force(
3010         struct xfs_mount        *mp,
3011         uint                    flags,
3012         int                     *log_flushed)
3013 {
3014         struct log              *log = mp->m_log;
3015         struct xlog_in_core     *iclog;
3016         xfs_lsn_t               lsn;
3017
3018         XFS_STATS_INC(xs_log_force);
3019
3020         xlog_cil_push(log, 1);
3021
3022         spin_lock(&log->l_icloglock);
3023
3024         iclog = log->l_iclog;
3025         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3026                 spin_unlock(&log->l_icloglock);
3027                 return XFS_ERROR(EIO);
3028         }
3029
3030         /* If the head iclog is not active nor dirty, we just attach
3031          * ourselves to the head and go to sleep.
3032          */
3033         if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3034             iclog->ic_state == XLOG_STATE_DIRTY) {
3035                 /*
3036                  * If the head is dirty or (active and empty), then
3037                  * we need to look at the previous iclog.  If the previous
3038                  * iclog is active or dirty we are done.  There is nothing
3039                  * to sync out.  Otherwise, we attach ourselves to the
3040                  * previous iclog and go to sleep.
3041                  */
3042                 if (iclog->ic_state == XLOG_STATE_DIRTY ||
3043                     (atomic_read(&iclog->ic_refcnt) == 0
3044                      && iclog->ic_offset == 0)) {
3045                         iclog = iclog->ic_prev;
3046                         if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3047                             iclog->ic_state == XLOG_STATE_DIRTY)
3048                                 goto no_sleep;
3049                         else
3050                                 goto maybe_sleep;
3051                 } else {
3052                         if (atomic_read(&iclog->ic_refcnt) == 0) {
3053                                 /* We are the only one with access to this
3054                                  * iclog.  Flush it out now.  There should
3055                                  * be a roundoff of zero to show that someone
3056                                  * has already taken care of the roundoff from
3057                                  * the previous sync.
3058                                  */
3059                                 atomic_inc(&iclog->ic_refcnt);
3060                                 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3061                                 xlog_state_switch_iclogs(log, iclog, 0);
3062                                 spin_unlock(&log->l_icloglock);
3063
3064                                 if (xlog_state_release_iclog(log, iclog))
3065                                         return XFS_ERROR(EIO);
3066
3067                                 if (log_flushed)
3068                                         *log_flushed = 1;
3069                                 spin_lock(&log->l_icloglock);
3070                                 if (be64_to_cpu(iclog->ic_header.h_lsn) == lsn &&
3071                                     iclog->ic_state != XLOG_STATE_DIRTY)
3072                                         goto maybe_sleep;
3073                                 else
3074                                         goto no_sleep;
3075                         } else {
3076                                 /* Someone else is writing to this iclog.
3077                                  * Use its call to flush out the data.  However,
3078                                  * the other thread may not force out this LR,
3079                                  * so we mark it WANT_SYNC.
3080                                  */
3081                                 xlog_state_switch_iclogs(log, iclog, 0);
3082                                 goto maybe_sleep;
3083                         }
3084                 }
3085         }
3086
3087         /* By the time we come around again, the iclog could've been filled
3088          * which would give it another lsn.  If we have a new lsn, just
3089          * return because the relevant data has been flushed.
3090          */
3091 maybe_sleep:
3092         if (flags & XFS_LOG_SYNC) {
3093                 /*
3094                  * We must check if we're shutting down here, before
3095                  * we wait, while we're holding the l_icloglock.
3096                  * Then we check again after waking up, in case our
3097                  * sleep was disturbed by a bad news.
3098                  */
3099                 if (iclog->ic_state & XLOG_STATE_IOERROR) {
3100                         spin_unlock(&log->l_icloglock);
3101                         return XFS_ERROR(EIO);
3102                 }
3103                 XFS_STATS_INC(xs_log_force_sleep);
3104                 sv_wait(&iclog->ic_force_wait, PINOD, &log->l_icloglock, s);
3105                 /*
3106                  * No need to grab the log lock here since we're
3107                  * only deciding whether or not to return EIO
3108                  * and the memory read should be atomic.
3109                  */
3110                 if (iclog->ic_state & XLOG_STATE_IOERROR)
3111                         return XFS_ERROR(EIO);
3112                 if (log_flushed)
3113                         *log_flushed = 1;
3114         } else {
3115
3116 no_sleep:
3117                 spin_unlock(&log->l_icloglock);
3118         }
3119         return 0;
3120 }
3121
3122 /*
3123  * Wrapper for _xfs_log_force(), to be used when caller doesn't care
3124  * about errors or whether the log was flushed or not. This is the normal
3125  * interface to use when trying to unpin items or move the log forward.
3126  */
3127 void
3128 xfs_log_force(
3129         xfs_mount_t     *mp,
3130         uint            flags)
3131 {
3132         int     error;
3133
3134         error = _xfs_log_force(mp, flags, NULL);
3135         if (error) {
3136                 xfs_fs_cmn_err(CE_WARN, mp, "xfs_log_force: "
3137                         "error %d returned.", error);
3138         }
3139 }
3140
3141 /*
3142  * Force the in-core log to disk for a specific LSN.
3143  *
3144  * Find in-core log with lsn.
3145  *      If it is in the DIRTY state, just return.
3146  *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3147  *              state and go to sleep or return.
3148  *      If it is in any other state, go to sleep or return.
3149  *
3150  * Synchronous forces are implemented with a signal variable. All callers
3151  * to force a given lsn to disk will wait on a the sv attached to the
3152  * specific in-core log.  When given in-core log finally completes its
3153  * write to disk, that thread will wake up all threads waiting on the
3154  * sv.
3155  */
3156 int
3157 _xfs_log_force_lsn(
3158         struct xfs_mount        *mp,
3159         xfs_lsn_t               lsn,
3160         uint                    flags,
3161         int                     *log_flushed)
3162 {
3163         struct log              *log = mp->m_log;
3164         struct xlog_in_core     *iclog;
3165         int                     already_slept = 0;
3166
3167         ASSERT(lsn != 0);
3168
3169         XFS_STATS_INC(xs_log_force);
3170
3171         if (log->l_cilp) {
3172                 lsn = xlog_cil_push_lsn(log, lsn);
3173                 if (lsn == NULLCOMMITLSN)
3174                         return 0;
3175         }
3176
3177 try_again:
3178         spin_lock(&log->l_icloglock);
3179         iclog = log->l_iclog;
3180         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3181                 spin_unlock(&log->l_icloglock);
3182                 return XFS_ERROR(EIO);
3183         }
3184
3185         do {
3186                 if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3187                         iclog = iclog->ic_next;
3188                         continue;
3189                 }
3190
3191                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
3192                         spin_unlock(&log->l_icloglock);
3193                         return 0;
3194                 }
3195
3196                 if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3197                         /*
3198                          * We sleep here if we haven't already slept (e.g.
3199                          * this is the first time we've looked at the correct
3200                          * iclog buf) and the buffer before us is going to
3201                          * be sync'ed. The reason for this is that if we
3202                          * are doing sync transactions here, by waiting for
3203                          * the previous I/O to complete, we can allow a few
3204                          * more transactions into this iclog before we close
3205                          * it down.
3206                          *
3207                          * Otherwise, we mark the buffer WANT_SYNC, and bump
3208                          * up the refcnt so we can release the log (which
3209                          * drops the ref count).  The state switch keeps new
3210                          * transaction commits from using this buffer.  When
3211                          * the current commits finish writing into the buffer,
3212                          * the refcount will drop to zero and the buffer will
3213                          * go out then.
3214                          */
3215                         if (!already_slept &&
3216                             (iclog->ic_prev->ic_state &
3217                              (XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
3218                                 ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
3219
3220                                 XFS_STATS_INC(xs_log_force_sleep);
3221
3222                                 sv_wait(&iclog->ic_prev->ic_write_wait,
3223                                         PSWP, &log->l_icloglock, s);
3224                                 if (log_flushed)
3225                                         *log_flushed = 1;
3226                                 already_slept = 1;
3227                                 goto try_again;
3228                         }
3229                         atomic_inc(&iclog->ic_refcnt);
3230                         xlog_state_switch_iclogs(log, iclog, 0);
3231                         spin_unlock(&log->l_icloglock);
3232                         if (xlog_state_release_iclog(log, iclog))
3233                                 return XFS_ERROR(EIO);
3234                         if (log_flushed)
3235                                 *log_flushed = 1;
3236                         spin_lock(&log->l_icloglock);
3237                 }
3238
3239                 if ((flags & XFS_LOG_SYNC) && /* sleep */
3240                     !(iclog->ic_state &
3241                       (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))) {
3242                         /*
3243                          * Don't wait on completion if we know that we've
3244                          * gotten a log write error.
3245                          */
3246                         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3247                                 spin_unlock(&log->l_icloglock);
3248                                 return XFS_ERROR(EIO);
3249                         }
3250                         XFS_STATS_INC(xs_log_force_sleep);
3251                         sv_wait(&iclog->ic_force_wait, PSWP, &log->l_icloglock, s);
3252                         /*
3253                          * No need to grab the log lock here since we're
3254                          * only deciding whether or not to return EIO
3255                          * and the memory read should be atomic.
3256                          */
3257                         if (iclog->ic_state & XLOG_STATE_IOERROR)
3258                                 return XFS_ERROR(EIO);
3259
3260                         if (log_flushed)
3261                                 *log_flushed = 1;
3262                 } else {                /* just return */
3263                         spin_unlock(&log->l_icloglock);
3264                 }
3265
3266                 return 0;
3267         } while (iclog != log->l_iclog);
3268
3269         spin_unlock(&log->l_icloglock);
3270         return 0;
3271 }
3272
3273 /*
3274  * Wrapper for _xfs_log_force_lsn(), to be used when caller doesn't care
3275  * about errors or whether the log was flushed or not. This is the normal
3276  * interface to use when trying to unpin items or move the log forward.
3277  */
3278 void
3279 xfs_log_force_lsn(
3280         xfs_mount_t     *mp,
3281         xfs_lsn_t       lsn,
3282         uint            flags)
3283 {
3284         int     error;
3285
3286         error = _xfs_log_force_lsn(mp, lsn, flags, NULL);
3287         if (error) {
3288                 xfs_fs_cmn_err(CE_WARN, mp, "xfs_log_force: "
3289                         "error %d returned.", error);
3290         }
3291 }
3292
3293 /*
3294  * Called when we want to mark the current iclog as being ready to sync to
3295  * disk.
3296  */
3297 STATIC void
3298 xlog_state_want_sync(xlog_t *log, xlog_in_core_t *iclog)
3299 {
3300         assert_spin_locked(&log->l_icloglock);
3301
3302         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3303                 xlog_state_switch_iclogs(log, iclog, 0);
3304         } else {
3305                 ASSERT(iclog->ic_state &
3306                         (XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
3307         }
3308 }
3309
3310
3311 /*****************************************************************************
3312  *
3313  *              TICKET functions
3314  *
3315  *****************************************************************************
3316  */
3317
3318 /*
3319  * Free a used ticket when its refcount falls to zero.
3320  */
3321 void
3322 xfs_log_ticket_put(
3323         xlog_ticket_t   *ticket)
3324 {
3325         ASSERT(atomic_read(&ticket->t_ref) > 0);
3326         if (atomic_dec_and_test(&ticket->t_ref)) {
3327                 sv_destroy(&ticket->t_wait);
3328                 kmem_zone_free(xfs_log_ticket_zone, ticket);
3329         }
3330 }
3331
3332 xlog_ticket_t *
3333 xfs_log_ticket_get(
3334         xlog_ticket_t   *ticket)
3335 {
3336         ASSERT(atomic_read(&ticket->t_ref) > 0);
3337         atomic_inc(&ticket->t_ref);
3338         return ticket;
3339 }
3340
3341 xlog_tid_t
3342 xfs_log_get_trans_ident(
3343         struct xfs_trans        *tp)
3344 {
3345         return tp->t_ticket->t_tid;
3346 }
3347
3348 /*
3349  * Allocate and initialise a new log ticket.
3350  */
3351 xlog_ticket_t *
3352 xlog_ticket_alloc(
3353         struct log      *log,
3354         int             unit_bytes,
3355         int             cnt,
3356         char            client,
3357         uint            xflags,
3358         int             alloc_flags)
3359 {
3360         struct xlog_ticket *tic;
3361         uint            num_headers;
3362         int             iclog_space;
3363
3364         tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3365         if (!tic)
3366                 return NULL;
3367
3368         /*
3369          * Permanent reservations have up to 'cnt'-1 active log operations
3370          * in the log.  A unit in this case is the amount of space for one
3371          * of these log operations.  Normal reservations have a cnt of 1
3372          * and their unit amount is the total amount of space required.
3373          *
3374          * The following lines of code account for non-transaction data
3375          * which occupy space in the on-disk log.
3376          *
3377          * Normal form of a transaction is:
3378          * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3379          * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3380          *
3381          * We need to account for all the leadup data and trailer data
3382          * around the transaction data.
3383          * And then we need to account for the worst case in terms of using
3384          * more space.
3385          * The worst case will happen if:
3386          * - the placement of the transaction happens to be such that the
3387          *   roundoff is at its maximum
3388          * - the transaction data is synced before the commit record is synced
3389          *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3390          *   Therefore the commit record is in its own Log Record.
3391          *   This can happen as the commit record is called with its
3392          *   own region to xlog_write().
3393          *   This then means that in the worst case, roundoff can happen for
3394          *   the commit-rec as well.
3395          *   The commit-rec is smaller than padding in this scenario and so it is
3396          *   not added separately.
3397          */
3398
3399         /* for trans header */
3400         unit_bytes += sizeof(xlog_op_header_t);
3401         unit_bytes += sizeof(xfs_trans_header_t);
3402
3403         /* for start-rec */
3404         unit_bytes += sizeof(xlog_op_header_t);
3405
3406         /*
3407          * for LR headers - the space for data in an iclog is the size minus
3408          * the space used for the headers. If we use the iclog size, then we
3409          * undercalculate the number of headers required.
3410          *
3411          * Furthermore - the addition of op headers for split-recs might
3412          * increase the space required enough to require more log and op
3413          * headers, so take that into account too.
3414          *
3415          * IMPORTANT: This reservation makes the assumption that if this
3416          * transaction is the first in an iclog and hence has the LR headers
3417          * accounted to it, then the remaining space in the iclog is
3418          * exclusively for this transaction.  i.e. if the transaction is larger
3419          * than the iclog, it will be the only thing in that iclog.
3420          * Fundamentally, this means we must pass the entire log vector to
3421          * xlog_write to guarantee this.
3422          */
3423         iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3424         num_headers = howmany(unit_bytes, iclog_space);
3425
3426         /* for split-recs - ophdrs added when data split over LRs */
3427         unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3428
3429         /* add extra header reservations if we overrun */
3430         while (!num_headers ||
3431                howmany(unit_bytes, iclog_space) > num_headers) {
3432                 unit_bytes += sizeof(xlog_op_header_t);
3433                 num_headers++;
3434         }
3435         unit_bytes += log->l_iclog_hsize * num_headers;
3436
3437         /* for commit-rec LR header - note: padding will subsume the ophdr */
3438         unit_bytes += log->l_iclog_hsize;
3439
3440         /* for roundoff padding for transaction data and one for commit record */
3441         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3442             log->l_mp->m_sb.sb_logsunit > 1) {
3443                 /* log su roundoff */
3444                 unit_bytes += 2*log->l_mp->m_sb.sb_logsunit;
3445         } else {
3446                 /* BB roundoff */
3447                 unit_bytes += 2*BBSIZE;
3448         }
3449
3450         atomic_set(&tic->t_ref, 1);
3451         tic->t_unit_res         = unit_bytes;
3452         tic->t_curr_res         = unit_bytes;
3453         tic->t_cnt              = cnt;
3454         tic->t_ocnt             = cnt;
3455         tic->t_tid              = random32();
3456         tic->t_clientid         = client;
3457         tic->t_flags            = XLOG_TIC_INITED;
3458         tic->t_trans_type       = 0;
3459         if (xflags & XFS_LOG_PERM_RESERV)
3460                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3461         sv_init(&tic->t_wait, SV_DEFAULT, "logtick");
3462
3463         xlog_tic_reset_res(tic);
3464
3465         return tic;
3466 }
3467
3468
3469 /******************************************************************************
3470  *
3471  *              Log debug routines
3472  *
3473  ******************************************************************************
3474  */
3475 #if defined(DEBUG)
3476 /*
3477  * Make sure that the destination ptr is within the valid data region of
3478  * one of the iclogs.  This uses backup pointers stored in a different
3479  * part of the log in case we trash the log structure.
3480  */
3481 void
3482 xlog_verify_dest_ptr(
3483         struct log      *log,
3484         char            *ptr)
3485 {
3486         int i;
3487         int good_ptr = 0;
3488
3489         for (i = 0; i < log->l_iclog_bufs; i++) {
3490                 if (ptr >= log->l_iclog_bak[i] &&
3491                     ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3492                         good_ptr++;
3493         }
3494
3495         if (!good_ptr)
3496                 xlog_panic("xlog_verify_dest_ptr: invalid ptr");
3497 }
3498
3499 STATIC void
3500 xlog_verify_grant_head(xlog_t *log, int equals)
3501 {
3502     if (log->l_grant_reserve_cycle == log->l_grant_write_cycle) {
3503         if (equals)
3504             ASSERT(log->l_grant_reserve_bytes >= log->l_grant_write_bytes);
3505         else
3506             ASSERT(log->l_grant_reserve_bytes > log->l_grant_write_bytes);
3507     } else {
3508         ASSERT(log->l_grant_reserve_cycle-1 == log->l_grant_write_cycle);
3509         ASSERT(log->l_grant_write_bytes >= log->l_grant_reserve_bytes);
3510     }
3511 }       /* xlog_verify_grant_head */
3512
3513 /* check if it will fit */
3514 STATIC void
3515 xlog_verify_tail_lsn(xlog_t         *log,
3516                      xlog_in_core_t *iclog,
3517                      xfs_lsn_t      tail_lsn)
3518 {
3519     int blocks;
3520
3521     if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3522         blocks =
3523             log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3524         if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3525             xlog_panic("xlog_verify_tail_lsn: ran out of log space");
3526     } else {
3527         ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3528
3529         if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3530             xlog_panic("xlog_verify_tail_lsn: tail wrapped");
3531
3532         blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3533         if (blocks < BTOBB(iclog->ic_offset) + 1)
3534             xlog_panic("xlog_verify_tail_lsn: ran out of log space");
3535     }
3536 }       /* xlog_verify_tail_lsn */
3537
3538 /*
3539  * Perform a number of checks on the iclog before writing to disk.
3540  *
3541  * 1. Make sure the iclogs are still circular
3542  * 2. Make sure we have a good magic number
3543  * 3. Make sure we don't have magic numbers in the data
3544  * 4. Check fields of each log operation header for:
3545  *      A. Valid client identifier
3546  *      B. tid ptr value falls in valid ptr space (user space code)
3547  *      C. Length in log record header is correct according to the
3548  *              individual operation headers within record.
3549  * 5. When a bwrite will occur within 5 blocks of the front of the physical
3550  *      log, check the preceding blocks of the physical log to make sure all
3551  *      the cycle numbers agree with the current cycle number.
3552  */
3553 STATIC void
3554 xlog_verify_iclog(xlog_t         *log,
3555                   xlog_in_core_t *iclog,
3556                   int            count,
3557                   boolean_t      syncing)
3558 {
3559         xlog_op_header_t        *ophead;
3560         xlog_in_core_t          *icptr;
3561         xlog_in_core_2_t        *xhdr;
3562         xfs_caddr_t             ptr;
3563         xfs_caddr_t             base_ptr;
3564         __psint_t               field_offset;
3565         __uint8_t               clientid;
3566         int                     len, i, j, k, op_len;
3567         int                     idx;
3568
3569         /* check validity of iclog pointers */
3570         spin_lock(&log->l_icloglock);
3571         icptr = log->l_iclog;
3572         for (i=0; i < log->l_iclog_bufs; i++) {
3573                 if (icptr == NULL)
3574                         xlog_panic("xlog_verify_iclog: invalid ptr");
3575                 icptr = icptr->ic_next;
3576         }
3577         if (icptr != log->l_iclog)
3578                 xlog_panic("xlog_verify_iclog: corrupt iclog ring");
3579         spin_unlock(&log->l_icloglock);
3580
3581         /* check log magic numbers */
3582         if (be32_to_cpu(iclog->ic_header.h_magicno) != XLOG_HEADER_MAGIC_NUM)
3583                 xlog_panic("xlog_verify_iclog: invalid magic num");
3584
3585         ptr = (xfs_caddr_t) &iclog->ic_header;
3586         for (ptr += BBSIZE; ptr < ((xfs_caddr_t)&iclog->ic_header) + count;
3587              ptr += BBSIZE) {
3588                 if (be32_to_cpu(*(__be32 *)ptr) == XLOG_HEADER_MAGIC_NUM)
3589                         xlog_panic("xlog_verify_iclog: unexpected magic num");
3590         }
3591
3592         /* check fields */
3593         len = be32_to_cpu(iclog->ic_header.h_num_logops);
3594         ptr = iclog->ic_datap;
3595         base_ptr = ptr;
3596         ophead = (xlog_op_header_t *)ptr;
3597         xhdr = iclog->ic_data;
3598         for (i = 0; i < len; i++) {
3599                 ophead = (xlog_op_header_t *)ptr;
3600
3601                 /* clientid is only 1 byte */
3602                 field_offset = (__psint_t)
3603                                ((xfs_caddr_t)&(ophead->oh_clientid) - base_ptr);
3604                 if (syncing == B_FALSE || (field_offset & 0x1ff)) {
3605                         clientid = ophead->oh_clientid;
3606                 } else {
3607                         idx = BTOBBT((xfs_caddr_t)&(ophead->oh_clientid) - iclog->ic_datap);
3608                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3609                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3610                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3611                                 clientid = xlog_get_client_id(
3612                                         xhdr[j].hic_xheader.xh_cycle_data[k]);
3613                         } else {
3614                                 clientid = xlog_get_client_id(
3615                                         iclog->ic_header.h_cycle_data[idx]);
3616                         }
3617                 }
3618                 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3619                         cmn_err(CE_WARN, "xlog_verify_iclog: "
3620                                 "invalid clientid %d op 0x%p offset 0x%lx",
3621                                 clientid, ophead, (unsigned long)field_offset);
3622
3623                 /* check length */
3624                 field_offset = (__psint_t)
3625                                ((xfs_caddr_t)&(ophead->oh_len) - base_ptr);
3626                 if (syncing == B_FALSE || (field_offset & 0x1ff)) {
3627                         op_len = be32_to_cpu(ophead->oh_len);
3628                 } else {
3629                         idx = BTOBBT((__psint_t)&ophead->oh_len -
3630                                     (__psint_t)iclog->ic_datap);
3631                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3632                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3633                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3634                                 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3635                         } else {
3636                                 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3637                         }
3638                 }
3639                 ptr += sizeof(xlog_op_header_t) + op_len;
3640         }
3641 }       /* xlog_verify_iclog */
3642 #endif
3643
3644 /*
3645  * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3646  */
3647 STATIC int
3648 xlog_state_ioerror(
3649         xlog_t  *log)
3650 {
3651         xlog_in_core_t  *iclog, *ic;
3652
3653         iclog = log->l_iclog;
3654         if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
3655                 /*
3656                  * Mark all the incore logs IOERROR.
3657                  * From now on, no log flushes will result.
3658                  */
3659                 ic = iclog;
3660                 do {
3661                         ic->ic_state = XLOG_STATE_IOERROR;
3662                         ic = ic->ic_next;
3663                 } while (ic != iclog);
3664                 return 0;
3665         }
3666         /*
3667          * Return non-zero, if state transition has already happened.
3668          */
3669         return 1;
3670 }
3671
3672 /*
3673  * This is called from xfs_force_shutdown, when we're forcibly
3674  * shutting down the filesystem, typically because of an IO error.
3675  * Our main objectives here are to make sure that:
3676  *      a. the filesystem gets marked 'SHUTDOWN' for all interested
3677  *         parties to find out, 'atomically'.
3678  *      b. those who're sleeping on log reservations, pinned objects and
3679  *          other resources get woken up, and be told the bad news.
3680  *      c. nothing new gets queued up after (a) and (b) are done.
3681  *      d. if !logerror, flush the iclogs to disk, then seal them off
3682  *         for business.
3683  *
3684  * Note: for delayed logging the !logerror case needs to flush the regions
3685  * held in memory out to the iclogs before flushing them to disk. This needs
3686  * to be done before the log is marked as shutdown, otherwise the flush to the
3687  * iclogs will fail.
3688  */
3689 int
3690 xfs_log_force_umount(
3691         struct xfs_mount        *mp,
3692         int                     logerror)
3693 {
3694         xlog_ticket_t   *tic;
3695         xlog_t          *log;
3696         int             retval;
3697
3698         log = mp->m_log;
3699
3700         /*
3701          * If this happens during log recovery, don't worry about
3702          * locking; the log isn't open for business yet.
3703          */
3704         if (!log ||
3705             log->l_flags & XLOG_ACTIVE_RECOVERY) {
3706                 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3707                 if (mp->m_sb_bp)
3708                         XFS_BUF_DONE(mp->m_sb_bp);
3709                 return 0;
3710         }
3711
3712         /*
3713          * Somebody could've already done the hard work for us.
3714          * No need to get locks for this.
3715          */
3716         if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
3717                 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3718                 return 1;
3719         }
3720         retval = 0;
3721
3722         /*
3723          * Flush the in memory commit item list before marking the log as
3724          * being shut down. We need to do it in this order to ensure all the
3725          * completed transactions are flushed to disk with the xfs_log_force()
3726          * call below.
3727          */
3728         if (!logerror && (mp->m_flags & XFS_MOUNT_DELAYLOG))
3729                 xlog_cil_push(log, 1);
3730
3731         /*
3732          * We must hold both the GRANT lock and the LOG lock,
3733          * before we mark the filesystem SHUTDOWN and wake
3734          * everybody up to tell the bad news.
3735          */
3736         spin_lock(&log->l_icloglock);
3737         spin_lock(&log->l_grant_lock);
3738         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3739         if (mp->m_sb_bp)
3740                 XFS_BUF_DONE(mp->m_sb_bp);
3741
3742         /*
3743          * This flag is sort of redundant because of the mount flag, but
3744          * it's good to maintain the separation between the log and the rest
3745          * of XFS.
3746          */
3747         log->l_flags |= XLOG_IO_ERROR;
3748
3749         /*
3750          * If we hit a log error, we want to mark all the iclogs IOERROR
3751          * while we're still holding the loglock.
3752          */
3753         if (logerror)
3754                 retval = xlog_state_ioerror(log);
3755         spin_unlock(&log->l_icloglock);
3756
3757         /*
3758          * We don't want anybody waiting for log reservations
3759          * after this. That means we have to wake up everybody
3760          * queued up on reserve_headq as well as write_headq.
3761          * In addition, we make sure in xlog_{re}grant_log_space
3762          * that we don't enqueue anything once the SHUTDOWN flag
3763          * is set, and this action is protected by the GRANTLOCK.
3764          */
3765         if ((tic = log->l_reserve_headq)) {
3766                 do {
3767                         sv_signal(&tic->t_wait);
3768                         tic = tic->t_next;
3769                 } while (tic != log->l_reserve_headq);
3770         }
3771
3772         if ((tic = log->l_write_headq)) {
3773                 do {
3774                         sv_signal(&tic->t_wait);
3775                         tic = tic->t_next;
3776                 } while (tic != log->l_write_headq);
3777         }
3778         spin_unlock(&log->l_grant_lock);
3779
3780         if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
3781                 ASSERT(!logerror);
3782                 /*
3783                  * Force the incore logs to disk before shutting the
3784                  * log down completely.
3785                  */
3786                 _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
3787
3788                 spin_lock(&log->l_icloglock);
3789                 retval = xlog_state_ioerror(log);
3790                 spin_unlock(&log->l_icloglock);
3791         }
3792         /*
3793          * Wake up everybody waiting on xfs_log_force.
3794          * Callback all log item committed functions as if the
3795          * log writes were completed.
3796          */
3797         xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
3798
3799 #ifdef XFSERRORDEBUG
3800         {
3801                 xlog_in_core_t  *iclog;
3802
3803                 spin_lock(&log->l_icloglock);
3804                 iclog = log->l_iclog;
3805                 do {
3806                         ASSERT(iclog->ic_callback == 0);
3807                         iclog = iclog->ic_next;
3808                 } while (iclog != log->l_iclog);
3809                 spin_unlock(&log->l_icloglock);
3810         }
3811 #endif
3812         /* return non-zero if log IOERROR transition had already happened */
3813         return retval;
3814 }
3815
3816 STATIC int
3817 xlog_iclogs_empty(xlog_t *log)
3818 {
3819         xlog_in_core_t  *iclog;
3820
3821         iclog = log->l_iclog;
3822         do {
3823                 /* endianness does not matter here, zero is zero in
3824                  * any language.
3825                  */
3826                 if (iclog->ic_header.h_num_logops)
3827                         return 0;
3828                 iclog = iclog->ic_next;
3829         } while (iclog != log->l_iclog);
3830         return 1;
3831 }