[MTD] NAND extended commands, badb block table autorefresh
[linux-2.6] / drivers / md / raid0.c
1 /*
2    raid0.c : Multiple Devices driver for Linux
3              Copyright (C) 1994-96 Marc ZYNGIER
4              <zyngier@ufr-info-p7.ibp.fr> or
5              <maz@gloups.fdn.fr>
6              Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
7
8
9    RAID-0 management functions.
10
11    This program is free software; you can redistribute it and/or modify
12    it under the terms of the GNU General Public License as published by
13    the Free Software Foundation; either version 2, or (at your option)
14    any later version.
15    
16    You should have received a copy of the GNU General Public License
17    (for example /usr/src/linux/COPYING); if not, write to the Free
18    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
19 */
20
21 #include <linux/module.h>
22 #include <linux/raid/raid0.h>
23
24 #define MAJOR_NR MD_MAJOR
25 #define MD_DRIVER
26 #define MD_PERSONALITY
27
28 static void raid0_unplug(request_queue_t *q)
29 {
30         mddev_t *mddev = q->queuedata;
31         raid0_conf_t *conf = mddev_to_conf(mddev);
32         mdk_rdev_t **devlist = conf->strip_zone[0].dev;
33         int i;
34
35         for (i=0; i<mddev->raid_disks; i++) {
36                 request_queue_t *r_queue = bdev_get_queue(devlist[i]->bdev);
37
38                 if (r_queue->unplug_fn)
39                         r_queue->unplug_fn(r_queue);
40         }
41 }
42
43 static int raid0_issue_flush(request_queue_t *q, struct gendisk *disk,
44                              sector_t *error_sector)
45 {
46         mddev_t *mddev = q->queuedata;
47         raid0_conf_t *conf = mddev_to_conf(mddev);
48         mdk_rdev_t **devlist = conf->strip_zone[0].dev;
49         int i, ret = 0;
50
51         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
52                 struct block_device *bdev = devlist[i]->bdev;
53                 request_queue_t *r_queue = bdev_get_queue(bdev);
54
55                 if (!r_queue->issue_flush_fn)
56                         ret = -EOPNOTSUPP;
57                 else
58                         ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
59         }
60         return ret;
61 }
62
63
64 static int create_strip_zones (mddev_t *mddev)
65 {
66         int i, c, j;
67         sector_t current_offset, curr_zone_offset;
68         sector_t min_spacing;
69         raid0_conf_t *conf = mddev_to_conf(mddev);
70         mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
71         struct list_head *tmp1, *tmp2;
72         struct strip_zone *zone;
73         int cnt;
74         char b[BDEVNAME_SIZE];
75  
76         /*
77          * The number of 'same size groups'
78          */
79         conf->nr_strip_zones = 0;
80  
81         ITERATE_RDEV(mddev,rdev1,tmp1) {
82                 printk("raid0: looking at %s\n",
83                         bdevname(rdev1->bdev,b));
84                 c = 0;
85                 ITERATE_RDEV(mddev,rdev2,tmp2) {
86                         printk("raid0:   comparing %s(%llu)",
87                                bdevname(rdev1->bdev,b),
88                                (unsigned long long)rdev1->size);
89                         printk(" with %s(%llu)\n",
90                                bdevname(rdev2->bdev,b),
91                                (unsigned long long)rdev2->size);
92                         if (rdev2 == rdev1) {
93                                 printk("raid0:   END\n");
94                                 break;
95                         }
96                         if (rdev2->size == rdev1->size)
97                         {
98                                 /*
99                                  * Not unique, don't count it as a new
100                                  * group
101                                  */
102                                 printk("raid0:   EQUAL\n");
103                                 c = 1;
104                                 break;
105                         }
106                         printk("raid0:   NOT EQUAL\n");
107                 }
108                 if (!c) {
109                         printk("raid0:   ==> UNIQUE\n");
110                         conf->nr_strip_zones++;
111                         printk("raid0: %d zones\n", conf->nr_strip_zones);
112                 }
113         }
114         printk("raid0: FINAL %d zones\n", conf->nr_strip_zones);
115
116         conf->strip_zone = kmalloc(sizeof(struct strip_zone)*
117                                 conf->nr_strip_zones, GFP_KERNEL);
118         if (!conf->strip_zone)
119                 return 1;
120         conf->devlist = kmalloc(sizeof(mdk_rdev_t*)*
121                                 conf->nr_strip_zones*mddev->raid_disks,
122                                 GFP_KERNEL);
123         if (!conf->devlist)
124                 return 1;
125
126         memset(conf->strip_zone, 0,sizeof(struct strip_zone)*
127                                    conf->nr_strip_zones);
128         memset(conf->devlist, 0,
129                sizeof(mdk_rdev_t*) * conf->nr_strip_zones * mddev->raid_disks);
130
131         /* The first zone must contain all devices, so here we check that
132          * there is a proper alignment of slots to devices and find them all
133          */
134         zone = &conf->strip_zone[0];
135         cnt = 0;
136         smallest = NULL;
137         zone->dev = conf->devlist;
138         ITERATE_RDEV(mddev, rdev1, tmp1) {
139                 int j = rdev1->raid_disk;
140
141                 if (j < 0 || j >= mddev->raid_disks) {
142                         printk("raid0: bad disk number %d - aborting!\n", j);
143                         goto abort;
144                 }
145                 if (zone->dev[j]) {
146                         printk("raid0: multiple devices for %d - aborting!\n",
147                                 j);
148                         goto abort;
149                 }
150                 zone->dev[j] = rdev1;
151
152                 blk_queue_stack_limits(mddev->queue,
153                                        rdev1->bdev->bd_disk->queue);
154                 /* as we don't honour merge_bvec_fn, we must never risk
155                  * violating it, so limit ->max_sector to one PAGE, as
156                  * a one page request is never in violation.
157                  */
158
159                 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
160                     mddev->queue->max_sectors > (PAGE_SIZE>>9))
161                         blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
162
163                 if (!smallest || (rdev1->size <smallest->size))
164                         smallest = rdev1;
165                 cnt++;
166         }
167         if (cnt != mddev->raid_disks) {
168                 printk("raid0: too few disks (%d of %d) - aborting!\n",
169                         cnt, mddev->raid_disks);
170                 goto abort;
171         }
172         zone->nb_dev = cnt;
173         zone->size = smallest->size * cnt;
174         zone->zone_offset = 0;
175
176         current_offset = smallest->size;
177         curr_zone_offset = zone->size;
178
179         /* now do the other zones */
180         for (i = 1; i < conf->nr_strip_zones; i++)
181         {
182                 zone = conf->strip_zone + i;
183                 zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks;
184
185                 printk("raid0: zone %d\n", i);
186                 zone->dev_offset = current_offset;
187                 smallest = NULL;
188                 c = 0;
189
190                 for (j=0; j<cnt; j++) {
191                         char b[BDEVNAME_SIZE];
192                         rdev = conf->strip_zone[0].dev[j];
193                         printk("raid0: checking %s ...", bdevname(rdev->bdev,b));
194                         if (rdev->size > current_offset)
195                         {
196                                 printk(" contained as device %d\n", c);
197                                 zone->dev[c] = rdev;
198                                 c++;
199                                 if (!smallest || (rdev->size <smallest->size)) {
200                                         smallest = rdev;
201                                         printk("  (%llu) is smallest!.\n", 
202                                                 (unsigned long long)rdev->size);
203                                 }
204                         } else
205                                 printk(" nope.\n");
206                 }
207
208                 zone->nb_dev = c;
209                 zone->size = (smallest->size - current_offset) * c;
210                 printk("raid0: zone->nb_dev: %d, size: %llu\n",
211                         zone->nb_dev, (unsigned long long)zone->size);
212
213                 zone->zone_offset = curr_zone_offset;
214                 curr_zone_offset += zone->size;
215
216                 current_offset = smallest->size;
217                 printk("raid0: current zone offset: %llu\n",
218                         (unsigned long long)current_offset);
219         }
220
221         /* Now find appropriate hash spacing.
222          * We want a number which causes most hash entries to cover
223          * at most two strips, but the hash table must be at most
224          * 1 PAGE.  We choose the smallest strip, or contiguous collection
225          * of strips, that has big enough size.  We never consider the last
226          * strip though as it's size has no bearing on the efficacy of the hash
227          * table.
228          */
229         conf->hash_spacing = curr_zone_offset;
230         min_spacing = curr_zone_offset;
231         sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
232         for (i=0; i < conf->nr_strip_zones-1; i++) {
233                 sector_t sz = 0;
234                 for (j=i; j<conf->nr_strip_zones-1 &&
235                              sz < min_spacing ; j++)
236                         sz += conf->strip_zone[j].size;
237                 if (sz >= min_spacing && sz < conf->hash_spacing)
238                         conf->hash_spacing = sz;
239         }
240
241         mddev->queue->unplug_fn = raid0_unplug;
242
243         mddev->queue->issue_flush_fn = raid0_issue_flush;
244
245         printk("raid0: done.\n");
246         return 0;
247  abort:
248         return 1;
249 }
250
251 /**
252  *      raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
253  *      @q: request queue
254  *      @bio: the buffer head that's been built up so far
255  *      @biovec: the request that could be merged to it.
256  *
257  *      Return amount of bytes we can accept at this offset
258  */
259 static int raid0_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec)
260 {
261         mddev_t *mddev = q->queuedata;
262         sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
263         int max;
264         unsigned int chunk_sectors = mddev->chunk_size >> 9;
265         unsigned int bio_sectors = bio->bi_size >> 9;
266
267         max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
268         if (max < 0) max = 0; /* bio_add cannot handle a negative return */
269         if (max <= biovec->bv_len && bio_sectors == 0)
270                 return biovec->bv_len;
271         else 
272                 return max;
273 }
274
275 static int raid0_run (mddev_t *mddev)
276 {
277         unsigned  cur=0, i=0, nb_zone;
278         s64 size;
279         raid0_conf_t *conf;
280         mdk_rdev_t *rdev;
281         struct list_head *tmp;
282
283         printk("%s: setting max_sectors to %d, segment boundary to %d\n",
284                mdname(mddev),
285                mddev->chunk_size >> 9,
286                (mddev->chunk_size>>1)-1);
287         blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
288         blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
289
290         conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
291         if (!conf)
292                 goto out;
293         mddev->private = (void *)conf;
294  
295         conf->strip_zone = NULL;
296         conf->devlist = NULL;
297         if (create_strip_zones (mddev)) 
298                 goto out_free_conf;
299
300         /* calculate array device size */
301         mddev->array_size = 0;
302         ITERATE_RDEV(mddev,rdev,tmp)
303                 mddev->array_size += rdev->size;
304
305         printk("raid0 : md_size is %llu blocks.\n", 
306                 (unsigned long long)mddev->array_size);
307         printk("raid0 : conf->hash_spacing is %llu blocks.\n",
308                 (unsigned long long)conf->hash_spacing);
309         {
310 #if __GNUC__ < 3
311                 volatile
312 #endif
313                 sector_t s = mddev->array_size;
314                 sector_t space = conf->hash_spacing;
315                 int round;
316                 conf->preshift = 0;
317                 if (sizeof(sector_t) > sizeof(unsigned long)) {
318                         /*shift down space and s so that sector_div will work */
319                         while (space > (sector_t) (~(unsigned long)0)) {
320                                 s >>= 1;
321                                 space >>= 1;
322                                 s += 1; /* force round-up */
323                                 conf->preshift++;
324                         }
325                 }
326                 round = sector_div(s, (unsigned long)space) ? 1 : 0;
327                 nb_zone = s + round;
328         }
329         printk("raid0 : nb_zone is %d.\n", nb_zone);
330
331         printk("raid0 : Allocating %Zd bytes for hash.\n",
332                                 nb_zone*sizeof(struct strip_zone*));
333         conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
334         if (!conf->hash_table)
335                 goto out_free_conf;
336         size = conf->strip_zone[cur].size;
337
338         for (i=0; i< nb_zone; i++) {
339                 conf->hash_table[i] = conf->strip_zone + cur;
340                 while (size <= conf->hash_spacing) {
341                         cur++;
342                         size += conf->strip_zone[cur].size;
343                 }
344                 size -= conf->hash_spacing;
345         }
346         if (conf->preshift) {
347                 conf->hash_spacing >>= conf->preshift;
348                 /* round hash_spacing up so when we divide by it, we
349                  * err on the side of too-low, which is safest
350                  */
351                 conf->hash_spacing++;
352         }
353
354         /* calculate the max read-ahead size.
355          * For read-ahead of large files to be effective, we need to
356          * readahead at least twice a whole stripe. i.e. number of devices
357          * multiplied by chunk size times 2.
358          * If an individual device has an ra_pages greater than the
359          * chunk size, then we will not drive that device as hard as it
360          * wants.  We consider this a configuration error: a larger
361          * chunksize should be used in that case.
362          */
363         {
364                 int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE;
365                 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
366                         mddev->queue->backing_dev_info.ra_pages = 2* stripe;
367         }
368
369
370         blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
371         return 0;
372
373 out_free_conf:
374         if (conf->strip_zone)
375                 kfree(conf->strip_zone);
376         if (conf->devlist)
377                 kfree (conf->devlist);
378         kfree(conf);
379         mddev->private = NULL;
380 out:
381         return 1;
382 }
383
384 static int raid0_stop (mddev_t *mddev)
385 {
386         raid0_conf_t *conf = mddev_to_conf(mddev);
387
388         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
389         kfree (conf->hash_table);
390         conf->hash_table = NULL;
391         kfree (conf->strip_zone);
392         conf->strip_zone = NULL;
393         kfree (conf);
394         mddev->private = NULL;
395
396         return 0;
397 }
398
399 static int raid0_make_request (request_queue_t *q, struct bio *bio)
400 {
401         mddev_t *mddev = q->queuedata;
402         unsigned int sect_in_chunk, chunksize_bits,  chunk_size, chunk_sects;
403         raid0_conf_t *conf = mddev_to_conf(mddev);
404         struct strip_zone *zone;
405         mdk_rdev_t *tmp_dev;
406         unsigned long chunk;
407         sector_t block, rsect;
408
409         if (bio_data_dir(bio)==WRITE) {
410                 disk_stat_inc(mddev->gendisk, writes);
411                 disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
412         } else {
413                 disk_stat_inc(mddev->gendisk, reads);
414                 disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
415         }
416
417         chunk_size = mddev->chunk_size >> 10;
418         chunk_sects = mddev->chunk_size >> 9;
419         chunksize_bits = ffz(~chunk_size);
420         block = bio->bi_sector >> 1;
421         
422
423         if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
424                 struct bio_pair *bp;
425                 /* Sanity check -- queue functions should prevent this happening */
426                 if (bio->bi_vcnt != 1 ||
427                     bio->bi_idx != 0)
428                         goto bad_map;
429                 /* This is a one page bio that upper layers
430                  * refuse to split for us, so we need to split it.
431                  */
432                 bp = bio_split(bio, bio_split_pool, chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
433                 if (raid0_make_request(q, &bp->bio1))
434                         generic_make_request(&bp->bio1);
435                 if (raid0_make_request(q, &bp->bio2))
436                         generic_make_request(&bp->bio2);
437
438                 bio_pair_release(bp);
439                 return 0;
440         }
441  
442
443         {
444 #if __GNUC__ < 3
445                 volatile
446 #endif
447                 sector_t x = block >> conf->preshift;
448                 sector_div(x, (unsigned long)conf->hash_spacing);
449                 zone = conf->hash_table[x];
450         }
451  
452         while (block >= (zone->zone_offset + zone->size)) 
453                 zone++;
454     
455         sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1);
456
457
458         {
459                 sector_t x =  (block - zone->zone_offset) >> chunksize_bits;
460
461                 sector_div(x, zone->nb_dev);
462                 chunk = x;
463                 BUG_ON(x != (sector_t)chunk);
464
465                 x = block >> chunksize_bits;
466                 tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
467         }
468         rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1)
469                 + sect_in_chunk;
470  
471         bio->bi_bdev = tmp_dev->bdev;
472         bio->bi_sector = rsect + tmp_dev->data_offset;
473
474         /*
475          * Let the main block layer submit the IO and resolve recursion:
476          */
477         return 1;
478
479 bad_map:
480         printk("raid0_make_request bug: can't convert block across chunks"
481                 " or bigger than %dk %llu %d\n", chunk_size, 
482                 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
483
484         bio_io_error(bio, bio->bi_size);
485         return 0;
486 }
487                            
488 static void raid0_status (struct seq_file *seq, mddev_t *mddev)
489 {
490 #undef MD_DEBUG
491 #ifdef MD_DEBUG
492         int j, k, h;
493         char b[BDEVNAME_SIZE];
494         raid0_conf_t *conf = mddev_to_conf(mddev);
495   
496         h = 0;
497         for (j = 0; j < conf->nr_strip_zones; j++) {
498                 seq_printf(seq, "      z%d", j);
499                 if (conf->hash_table[h] == conf->strip_zone+j)
500                         seq_printf("(h%d)", h++);
501                 seq_printf(seq, "=[");
502                 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
503                         seq_printf (seq, "%s/", bdevname(
504                                 conf->strip_zone[j].dev[k]->bdev,b));
505
506                 seq_printf (seq, "] zo=%d do=%d s=%d\n",
507                                 conf->strip_zone[j].zone_offset,
508                                 conf->strip_zone[j].dev_offset,
509                                 conf->strip_zone[j].size);
510         }
511 #endif
512         seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
513         return;
514 }
515
516 static mdk_personality_t raid0_personality=
517 {
518         .name           = "raid0",
519         .owner          = THIS_MODULE,
520         .make_request   = raid0_make_request,
521         .run            = raid0_run,
522         .stop           = raid0_stop,
523         .status         = raid0_status,
524 };
525
526 static int __init raid0_init (void)
527 {
528         return register_md_personality (RAID0, &raid0_personality);
529 }
530
531 static void raid0_exit (void)
532 {
533         unregister_md_personality (RAID0);
534 }
535
536 module_init(raid0_init);
537 module_exit(raid0_exit);
538 MODULE_LICENSE("GPL");
539 MODULE_ALIAS("md-personality-2"); /* RAID0 */