Fix pata_icside build for recent libata API changes
[linux-2.6] / drivers / md / dm-log.c
1 /*
2  * Copyright (C) 2003 Sistina Software
3  *
4  * This file is released under the LGPL.
5  */
6
7 #include <linux/init.h>
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 #include <linux/vmalloc.h>
11
12 #include "dm-log.h"
13 #include "dm-io.h"
14
15 #define DM_MSG_PREFIX "mirror log"
16
17 static LIST_HEAD(_log_types);
18 static DEFINE_SPINLOCK(_lock);
19
20 int dm_register_dirty_log_type(struct dirty_log_type *type)
21 {
22         spin_lock(&_lock);
23         type->use_count = 0;
24         list_add(&type->list, &_log_types);
25         spin_unlock(&_lock);
26
27         return 0;
28 }
29
30 int dm_unregister_dirty_log_type(struct dirty_log_type *type)
31 {
32         spin_lock(&_lock);
33
34         if (type->use_count)
35                 DMWARN("Attempt to unregister a log type that is still in use");
36         else
37                 list_del(&type->list);
38
39         spin_unlock(&_lock);
40
41         return 0;
42 }
43
44 static struct dirty_log_type *get_type(const char *type_name)
45 {
46         struct dirty_log_type *type;
47
48         spin_lock(&_lock);
49         list_for_each_entry (type, &_log_types, list)
50                 if (!strcmp(type_name, type->name)) {
51                         if (!type->use_count && !try_module_get(type->module)){
52                                 spin_unlock(&_lock);
53                                 return NULL;
54                         }
55                         type->use_count++;
56                         spin_unlock(&_lock);
57                         return type;
58                 }
59
60         spin_unlock(&_lock);
61         return NULL;
62 }
63
64 static void put_type(struct dirty_log_type *type)
65 {
66         spin_lock(&_lock);
67         if (!--type->use_count)
68                 module_put(type->module);
69         spin_unlock(&_lock);
70 }
71
72 struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
73                                       unsigned int argc, char **argv)
74 {
75         struct dirty_log_type *type;
76         struct dirty_log *log;
77
78         log = kmalloc(sizeof(*log), GFP_KERNEL);
79         if (!log)
80                 return NULL;
81
82         type = get_type(type_name);
83         if (!type) {
84                 kfree(log);
85                 return NULL;
86         }
87
88         log->type = type;
89         if (type->ctr(log, ti, argc, argv)) {
90                 kfree(log);
91                 put_type(type);
92                 return NULL;
93         }
94
95         return log;
96 }
97
98 void dm_destroy_dirty_log(struct dirty_log *log)
99 {
100         log->type->dtr(log);
101         put_type(log->type);
102         kfree(log);
103 }
104
105 /*-----------------------------------------------------------------
106  * Persistent and core logs share a lot of their implementation.
107  * FIXME: need a reload method to be called from a resume
108  *---------------------------------------------------------------*/
109 /*
110  * Magic for persistent mirrors: "MiRr"
111  */
112 #define MIRROR_MAGIC 0x4D695272
113
114 /*
115  * The on-disk version of the metadata.
116  */
117 #define MIRROR_DISK_VERSION 2
118 #define LOG_OFFSET 2
119
120 struct log_header {
121         uint32_t magic;
122
123         /*
124          * Simple, incrementing version. no backward
125          * compatibility.
126          */
127         uint32_t version;
128         sector_t nr_regions;
129 };
130
131 struct log_c {
132         struct dm_target *ti;
133         int touched;
134         uint32_t region_size;
135         unsigned int region_count;
136         region_t sync_count;
137
138         unsigned bitset_uint32_count;
139         uint32_t *clean_bits;
140         uint32_t *sync_bits;
141         uint32_t *recovering_bits;      /* FIXME: this seems excessive */
142
143         int sync_search;
144
145         /* Resync flag */
146         enum sync {
147                 DEFAULTSYNC,    /* Synchronize if necessary */
148                 NOSYNC,         /* Devices known to be already in sync */
149                 FORCESYNC,      /* Force a sync to happen */
150         } sync;
151
152         struct dm_io_request io_req;
153
154         /*
155          * Disk log fields
156          */
157         int log_dev_failed;
158         struct dm_dev *log_dev;
159         struct log_header header;
160
161         struct io_region header_location;
162         struct log_header *disk_header;
163 };
164
165 /*
166  * The touched member needs to be updated every time we access
167  * one of the bitsets.
168  */
169 static  inline int log_test_bit(uint32_t *bs, unsigned bit)
170 {
171         return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;
172 }
173
174 static inline void log_set_bit(struct log_c *l,
175                                uint32_t *bs, unsigned bit)
176 {
177         ext2_set_bit(bit, (unsigned long *) bs);
178         l->touched = 1;
179 }
180
181 static inline void log_clear_bit(struct log_c *l,
182                                  uint32_t *bs, unsigned bit)
183 {
184         ext2_clear_bit(bit, (unsigned long *) bs);
185         l->touched = 1;
186 }
187
188 /*----------------------------------------------------------------
189  * Header IO
190  *--------------------------------------------------------------*/
191 static void header_to_disk(struct log_header *core, struct log_header *disk)
192 {
193         disk->magic = cpu_to_le32(core->magic);
194         disk->version = cpu_to_le32(core->version);
195         disk->nr_regions = cpu_to_le64(core->nr_regions);
196 }
197
198 static void header_from_disk(struct log_header *core, struct log_header *disk)
199 {
200         core->magic = le32_to_cpu(disk->magic);
201         core->version = le32_to_cpu(disk->version);
202         core->nr_regions = le64_to_cpu(disk->nr_regions);
203 }
204
205 static int rw_header(struct log_c *lc, int rw)
206 {
207         lc->io_req.bi_rw = rw;
208         lc->io_req.mem.ptr.vma = lc->disk_header;
209         lc->io_req.notify.fn = NULL;
210
211         return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
212 }
213
214 static int read_header(struct log_c *log)
215 {
216         int r;
217
218         r = rw_header(log, READ);
219         if (r)
220                 return r;
221
222         header_from_disk(&log->header, log->disk_header);
223
224         /* New log required? */
225         if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
226                 log->header.magic = MIRROR_MAGIC;
227                 log->header.version = MIRROR_DISK_VERSION;
228                 log->header.nr_regions = 0;
229         }
230
231 #ifdef __LITTLE_ENDIAN
232         if (log->header.version == 1)
233                 log->header.version = 2;
234 #endif
235
236         if (log->header.version != MIRROR_DISK_VERSION) {
237                 DMWARN("incompatible disk log version");
238                 return -EINVAL;
239         }
240
241         return 0;
242 }
243
244 static inline int write_header(struct log_c *log)
245 {
246         header_to_disk(&log->header, log->disk_header);
247         return rw_header(log, WRITE);
248 }
249
250 /*----------------------------------------------------------------
251  * core log constructor/destructor
252  *
253  * argv contains region_size followed optionally by [no]sync
254  *--------------------------------------------------------------*/
255 #define BYTE_SHIFT 3
256 static int create_log_context(struct dirty_log *log, struct dm_target *ti,
257                               unsigned int argc, char **argv,
258                               struct dm_dev *dev)
259 {
260         enum sync sync = DEFAULTSYNC;
261
262         struct log_c *lc;
263         uint32_t region_size;
264         unsigned int region_count;
265         size_t bitset_size, buf_size;
266         int r;
267
268         if (argc < 1 || argc > 2) {
269                 DMWARN("wrong number of arguments to mirror log");
270                 return -EINVAL;
271         }
272
273         if (argc > 1) {
274                 if (!strcmp(argv[1], "sync"))
275                         sync = FORCESYNC;
276                 else if (!strcmp(argv[1], "nosync"))
277                         sync = NOSYNC;
278                 else {
279                         DMWARN("unrecognised sync argument to mirror log: %s",
280                                argv[1]);
281                         return -EINVAL;
282                 }
283         }
284
285         if (sscanf(argv[0], "%u", &region_size) != 1) {
286                 DMWARN("invalid region size string");
287                 return -EINVAL;
288         }
289
290         region_count = dm_sector_div_up(ti->len, region_size);
291
292         lc = kmalloc(sizeof(*lc), GFP_KERNEL);
293         if (!lc) {
294                 DMWARN("couldn't allocate core log");
295                 return -ENOMEM;
296         }
297
298         lc->ti = ti;
299         lc->touched = 0;
300         lc->region_size = region_size;
301         lc->region_count = region_count;
302         lc->sync = sync;
303
304         /*
305          * Work out how many "unsigned long"s we need to hold the bitset.
306          */
307         bitset_size = dm_round_up(region_count,
308                                   sizeof(*lc->clean_bits) << BYTE_SHIFT);
309         bitset_size >>= BYTE_SHIFT;
310
311         lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
312
313         /*
314          * Disk log?
315          */
316         if (!dev) {
317                 lc->clean_bits = vmalloc(bitset_size);
318                 if (!lc->clean_bits) {
319                         DMWARN("couldn't allocate clean bitset");
320                         kfree(lc);
321                         return -ENOMEM;
322                 }
323                 lc->disk_header = NULL;
324         } else {
325                 lc->log_dev = dev;
326                 lc->log_dev_failed = 0;
327                 lc->header_location.bdev = lc->log_dev->bdev;
328                 lc->header_location.sector = 0;
329
330                 /*
331                  * Buffer holds both header and bitset.
332                  */
333                 buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
334                                        bitset_size, ti->limits.hardsect_size);
335                 lc->header_location.count = buf_size >> SECTOR_SHIFT;
336                 lc->io_req.mem.type = DM_IO_VMA;
337                 lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
338                                                                    PAGE_SIZE));
339                 if (IS_ERR(lc->io_req.client)) {
340                         r = PTR_ERR(lc->io_req.client);
341                         DMWARN("couldn't allocate disk io client");
342                         kfree(lc);
343                         return -ENOMEM;
344                 }
345
346                 lc->disk_header = vmalloc(buf_size);
347                 if (!lc->disk_header) {
348                         DMWARN("couldn't allocate disk log buffer");
349                         kfree(lc);
350                         return -ENOMEM;
351                 }
352
353                 lc->clean_bits = (void *)lc->disk_header +
354                                  (LOG_OFFSET << SECTOR_SHIFT);
355         }
356
357         memset(lc->clean_bits, -1, bitset_size);
358
359         lc->sync_bits = vmalloc(bitset_size);
360         if (!lc->sync_bits) {
361                 DMWARN("couldn't allocate sync bitset");
362                 if (!dev)
363                         vfree(lc->clean_bits);
364                 vfree(lc->disk_header);
365                 kfree(lc);
366                 return -ENOMEM;
367         }
368         memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
369         lc->sync_count = (sync == NOSYNC) ? region_count : 0;
370
371         lc->recovering_bits = vmalloc(bitset_size);
372         if (!lc->recovering_bits) {
373                 DMWARN("couldn't allocate sync bitset");
374                 vfree(lc->sync_bits);
375                 if (!dev)
376                         vfree(lc->clean_bits);
377                 vfree(lc->disk_header);
378                 kfree(lc);
379                 return -ENOMEM;
380         }
381         memset(lc->recovering_bits, 0, bitset_size);
382         lc->sync_search = 0;
383         log->context = lc;
384
385         return 0;
386 }
387
388 static int core_ctr(struct dirty_log *log, struct dm_target *ti,
389                     unsigned int argc, char **argv)
390 {
391         return create_log_context(log, ti, argc, argv, NULL);
392 }
393
394 static void destroy_log_context(struct log_c *lc)
395 {
396         vfree(lc->sync_bits);
397         vfree(lc->recovering_bits);
398         kfree(lc);
399 }
400
401 static void core_dtr(struct dirty_log *log)
402 {
403         struct log_c *lc = (struct log_c *) log->context;
404
405         vfree(lc->clean_bits);
406         destroy_log_context(lc);
407 }
408
409 /*----------------------------------------------------------------
410  * disk log constructor/destructor
411  *
412  * argv contains log_device region_size followed optionally by [no]sync
413  *--------------------------------------------------------------*/
414 static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
415                     unsigned int argc, char **argv)
416 {
417         int r;
418         struct dm_dev *dev;
419
420         if (argc < 2 || argc > 3) {
421                 DMWARN("wrong number of arguments to disk mirror log");
422                 return -EINVAL;
423         }
424
425         r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
426                           FMODE_READ | FMODE_WRITE, &dev);
427         if (r)
428                 return r;
429
430         r = create_log_context(log, ti, argc - 1, argv + 1, dev);
431         if (r) {
432                 dm_put_device(ti, dev);
433                 return r;
434         }
435
436         return 0;
437 }
438
439 static void disk_dtr(struct dirty_log *log)
440 {
441         struct log_c *lc = (struct log_c *) log->context;
442
443         dm_put_device(lc->ti, lc->log_dev);
444         vfree(lc->disk_header);
445         dm_io_client_destroy(lc->io_req.client);
446         destroy_log_context(lc);
447 }
448
449 static int count_bits32(uint32_t *addr, unsigned size)
450 {
451         int count = 0, i;
452
453         for (i = 0; i < size; i++) {
454                 count += hweight32(*(addr+i));
455         }
456         return count;
457 }
458
459 static void fail_log_device(struct log_c *lc)
460 {
461         if (lc->log_dev_failed)
462                 return;
463
464         lc->log_dev_failed = 1;
465         dm_table_event(lc->ti->table);
466 }
467
468 static int disk_resume(struct dirty_log *log)
469 {
470         int r;
471         unsigned i;
472         struct log_c *lc = (struct log_c *) log->context;
473         size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
474
475         /* read the disk header */
476         r = read_header(lc);
477         if (r) {
478                 DMWARN("%s: Failed to read header on mirror log device",
479                        lc->log_dev->name);
480                 fail_log_device(lc);
481                 /*
482                  * If the log device cannot be read, we must assume
483                  * all regions are out-of-sync.  If we simply return
484                  * here, the state will be uninitialized and could
485                  * lead us to return 'in-sync' status for regions
486                  * that are actually 'out-of-sync'.
487                  */
488                 lc->header.nr_regions = 0;
489         }
490
491         /* set or clear any new bits -- device has grown */
492         if (lc->sync == NOSYNC)
493                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
494                         /* FIXME: amazingly inefficient */
495                         log_set_bit(lc, lc->clean_bits, i);
496         else
497                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
498                         /* FIXME: amazingly inefficient */
499                         log_clear_bit(lc, lc->clean_bits, i);
500
501         /* clear any old bits -- device has shrunk */
502         for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
503                 log_clear_bit(lc, lc->clean_bits, i);
504
505         /* copy clean across to sync */
506         memcpy(lc->sync_bits, lc->clean_bits, size);
507         lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
508         lc->sync_search = 0;
509
510         /* set the correct number of regions in the header */
511         lc->header.nr_regions = lc->region_count;
512
513         /* write the new header */
514         r = write_header(lc);
515         if (r) {
516                 DMWARN("%s: Failed to write header on mirror log device",
517                        lc->log_dev->name);
518                 fail_log_device(lc);
519         }
520
521         return r;
522 }
523
524 static uint32_t core_get_region_size(struct dirty_log *log)
525 {
526         struct log_c *lc = (struct log_c *) log->context;
527         return lc->region_size;
528 }
529
530 static int core_resume(struct dirty_log *log)
531 {
532         struct log_c *lc = (struct log_c *) log->context;
533         lc->sync_search = 0;
534         return 0;
535 }
536
537 static int core_is_clean(struct dirty_log *log, region_t region)
538 {
539         struct log_c *lc = (struct log_c *) log->context;
540         return log_test_bit(lc->clean_bits, region);
541 }
542
543 static int core_in_sync(struct dirty_log *log, region_t region, int block)
544 {
545         struct log_c *lc = (struct log_c *) log->context;
546         return log_test_bit(lc->sync_bits, region);
547 }
548
549 static int core_flush(struct dirty_log *log)
550 {
551         /* no op */
552         return 0;
553 }
554
555 static int disk_flush(struct dirty_log *log)
556 {
557         int r;
558         struct log_c *lc = (struct log_c *) log->context;
559
560         /* only write if the log has changed */
561         if (!lc->touched)
562                 return 0;
563
564         r = write_header(lc);
565         if (r)
566                 fail_log_device(lc);
567         else
568                 lc->touched = 0;
569
570         return r;
571 }
572
573 static void core_mark_region(struct dirty_log *log, region_t region)
574 {
575         struct log_c *lc = (struct log_c *) log->context;
576         log_clear_bit(lc, lc->clean_bits, region);
577 }
578
579 static void core_clear_region(struct dirty_log *log, region_t region)
580 {
581         struct log_c *lc = (struct log_c *) log->context;
582         log_set_bit(lc, lc->clean_bits, region);
583 }
584
585 static int core_get_resync_work(struct dirty_log *log, region_t *region)
586 {
587         struct log_c *lc = (struct log_c *) log->context;
588
589         if (lc->sync_search >= lc->region_count)
590                 return 0;
591
592         do {
593                 *region = ext2_find_next_zero_bit(
594                                              (unsigned long *) lc->sync_bits,
595                                              lc->region_count,
596                                              lc->sync_search);
597                 lc->sync_search = *region + 1;
598
599                 if (*region >= lc->region_count)
600                         return 0;
601
602         } while (log_test_bit(lc->recovering_bits, *region));
603
604         log_set_bit(lc, lc->recovering_bits, *region);
605         return 1;
606 }
607
608 static void core_set_region_sync(struct dirty_log *log, region_t region,
609                                  int in_sync)
610 {
611         struct log_c *lc = (struct log_c *) log->context;
612
613         log_clear_bit(lc, lc->recovering_bits, region);
614         if (in_sync) {
615                 log_set_bit(lc, lc->sync_bits, region);
616                 lc->sync_count++;
617         } else if (log_test_bit(lc->sync_bits, region)) {
618                 lc->sync_count--;
619                 log_clear_bit(lc, lc->sync_bits, region);
620         }
621 }
622
623 static region_t core_get_sync_count(struct dirty_log *log)
624 {
625         struct log_c *lc = (struct log_c *) log->context;
626
627         return lc->sync_count;
628 }
629
630 #define DMEMIT_SYNC \
631         if (lc->sync != DEFAULTSYNC) \
632                 DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
633
634 static int core_status(struct dirty_log *log, status_type_t status,
635                        char *result, unsigned int maxlen)
636 {
637         int sz = 0;
638         struct log_c *lc = log->context;
639
640         switch(status) {
641         case STATUSTYPE_INFO:
642                 DMEMIT("1 %s", log->type->name);
643                 break;
644
645         case STATUSTYPE_TABLE:
646                 DMEMIT("%s %u %u ", log->type->name,
647                        lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
648                 DMEMIT_SYNC;
649         }
650
651         return sz;
652 }
653
654 static int disk_status(struct dirty_log *log, status_type_t status,
655                        char *result, unsigned int maxlen)
656 {
657         int sz = 0;
658         struct log_c *lc = log->context;
659
660         switch(status) {
661         case STATUSTYPE_INFO:
662                 DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
663                        lc->log_dev_failed ? 'D' : 'A');
664                 break;
665
666         case STATUSTYPE_TABLE:
667                 DMEMIT("%s %u %s %u ", log->type->name,
668                        lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
669                        lc->region_size);
670                 DMEMIT_SYNC;
671         }
672
673         return sz;
674 }
675
676 static struct dirty_log_type _core_type = {
677         .name = "core",
678         .module = THIS_MODULE,
679         .ctr = core_ctr,
680         .dtr = core_dtr,
681         .resume = core_resume,
682         .get_region_size = core_get_region_size,
683         .is_clean = core_is_clean,
684         .in_sync = core_in_sync,
685         .flush = core_flush,
686         .mark_region = core_mark_region,
687         .clear_region = core_clear_region,
688         .get_resync_work = core_get_resync_work,
689         .set_region_sync = core_set_region_sync,
690         .get_sync_count = core_get_sync_count,
691         .status = core_status,
692 };
693
694 static struct dirty_log_type _disk_type = {
695         .name = "disk",
696         .module = THIS_MODULE,
697         .ctr = disk_ctr,
698         .dtr = disk_dtr,
699         .postsuspend = disk_flush,
700         .resume = disk_resume,
701         .get_region_size = core_get_region_size,
702         .is_clean = core_is_clean,
703         .in_sync = core_in_sync,
704         .flush = disk_flush,
705         .mark_region = core_mark_region,
706         .clear_region = core_clear_region,
707         .get_resync_work = core_get_resync_work,
708         .set_region_sync = core_set_region_sync,
709         .get_sync_count = core_get_sync_count,
710         .status = disk_status,
711 };
712
713 int __init dm_dirty_log_init(void)
714 {
715         int r;
716
717         r = dm_register_dirty_log_type(&_core_type);
718         if (r)
719                 DMWARN("couldn't register core log");
720
721         r = dm_register_dirty_log_type(&_disk_type);
722         if (r) {
723                 DMWARN("couldn't register disk type");
724                 dm_unregister_dirty_log_type(&_core_type);
725         }
726
727         return r;
728 }
729
730 void dm_dirty_log_exit(void)
731 {
732         dm_unregister_dirty_log_type(&_disk_type);
733         dm_unregister_dirty_log_type(&_core_type);
734 }
735
736 EXPORT_SYMBOL(dm_register_dirty_log_type);
737 EXPORT_SYMBOL(dm_unregister_dirty_log_type);
738 EXPORT_SYMBOL(dm_create_dirty_log);
739 EXPORT_SYMBOL(dm_destroy_dirty_log);