2 * Copyright (C) 2011 Red Hat, Inc.
4 * This file is released under the GPL.
7 #include "dm-space-map.h"
8 #include "dm-space-map-common.h"
9 #include "dm-space-map-metadata.h"
11 #include <linux/list.h>
12 #include <linux/slab.h>
13 #include <linux/device-mapper.h>
15 #define DM_MSG_PREFIX "space map metadata"
17 /*----------------------------------------------------------------*/
20 * Space map interface.
22 * The low level disk format is written using the standard btree and
23 * transaction manager. This means that performing disk operations may
24 * cause us to recurse into the space map in order to allocate new blocks.
25 * For this reason we have a pool of pre-allocated blocks large enough to
26 * service any metadata_ll_disk operation.
30 * FIXME: we should calculate this based on the size of the device.
31 * Only the metadata space map needs this functionality.
33 #define MAX_RECURSIVE_ALLOCATIONS 1024
41 enum block_op_type type;
46 struct dm_space_map sm;
49 struct ll_disk old_ll;
53 unsigned recursion_count;
54 unsigned allocated_this_transaction;
55 unsigned nr_uncommitted;
56 struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS];
59 static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
63 if (smm->nr_uncommitted == MAX_RECURSIVE_ALLOCATIONS) {
64 DMERR("too many recursive allocations");
68 op = smm->uncommitted + smm->nr_uncommitted++;
75 static int commit_bop(struct sm_metadata *smm, struct block_op *op)
78 enum allocation_event ev;
82 r = sm_ll_inc(&smm->ll, op->block, &ev);
86 r = sm_ll_dec(&smm->ll, op->block, &ev);
93 static void in(struct sm_metadata *smm)
95 smm->recursion_count++;
98 static int out(struct sm_metadata *smm)
103 * If we're not recursing then very bad things are happening.
105 if (!smm->recursion_count) {
106 DMERR("lost track of recursion depth");
110 if (smm->recursion_count == 1 && smm->nr_uncommitted) {
111 while (smm->nr_uncommitted && !r) {
112 smm->nr_uncommitted--;
113 r = commit_bop(smm, smm->uncommitted +
114 smm->nr_uncommitted);
120 smm->recursion_count--;
126 * When using the out() function above, we often want to combine an error
127 * code for the operation run in the recursive context with that from
130 static int combine_errors(int r1, int r2)
135 static int recursing(struct sm_metadata *smm)
137 return smm->recursion_count;
140 static void sm_metadata_destroy(struct dm_space_map *sm)
142 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
147 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
149 DMERR("doesn't support extend");
153 static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
155 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
157 *count = smm->ll.nr_blocks;
162 static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
164 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
166 *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
167 smm->allocated_this_transaction;
172 static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
176 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
177 unsigned adjustment = 0;
180 * We may have some uncommitted adjustments to add. This list
181 * should always be really short.
183 for (i = 0; i < smm->nr_uncommitted; i++) {
184 struct block_op *op = smm->uncommitted + i;
200 r = sm_ll_lookup(&smm->ll, b, result);
204 *result += adjustment;
209 static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
210 dm_block_t b, int *result)
212 int r, i, adjustment = 0;
213 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
217 * We may have some uncommitted adjustments to add. This list
218 * should always be really short.
220 for (i = 0; i < smm->nr_uncommitted; i++) {
221 struct block_op *op = smm->uncommitted + i;
237 if (adjustment > 1) {
242 r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
248 * We err on the side of caution, and always return true.
252 *result = rc + adjustment > 1;
257 static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
261 enum allocation_event ev;
262 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
264 if (smm->recursion_count) {
265 DMERR("cannot recurse set_count()");
270 r = sm_ll_insert(&smm->ll, b, count, &ev);
273 return combine_errors(r, r2);
276 static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
279 enum allocation_event ev;
280 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
283 r = add_bop(smm, BOP_INC, b);
286 r = sm_ll_inc(&smm->ll, b, &ev);
290 return combine_errors(r, r2);
293 static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
296 enum allocation_event ev;
297 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
300 r = add_bop(smm, BOP_DEC, b);
303 r = sm_ll_dec(&smm->ll, b, &ev);
307 return combine_errors(r, r2);
310 static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
313 enum allocation_event ev;
314 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
316 r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b);
323 r = add_bop(smm, BOP_INC, *b);
326 r = sm_ll_inc(&smm->ll, *b, &ev);
331 smm->allocated_this_transaction++;
333 return combine_errors(r, r2);
336 static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
338 int r = sm_metadata_new_block_(sm, b);
340 DMERR("unable to allocate new metadata block");
344 static int sm_metadata_commit(struct dm_space_map *sm)
347 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
349 r = sm_ll_commit(&smm->ll);
353 memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
355 smm->allocated_this_transaction = 0;
360 static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
362 *result = sizeof(struct disk_sm_root);
367 static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
369 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
370 struct disk_sm_root root_le;
372 root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
373 root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
374 root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
375 root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
377 if (max < sizeof(root_le))
380 memcpy(where_le, &root_le, sizeof(root_le));
385 static struct dm_space_map ops = {
386 .destroy = sm_metadata_destroy,
387 .extend = sm_metadata_extend,
388 .get_nr_blocks = sm_metadata_get_nr_blocks,
389 .get_nr_free = sm_metadata_get_nr_free,
390 .get_count = sm_metadata_get_count,
391 .count_is_more_than_one = sm_metadata_count_is_more_than_one,
392 .set_count = sm_metadata_set_count,
393 .inc_block = sm_metadata_inc_block,
394 .dec_block = sm_metadata_dec_block,
395 .new_block = sm_metadata_new_block,
396 .commit = sm_metadata_commit,
397 .root_size = sm_metadata_root_size,
398 .copy_root = sm_metadata_copy_root
401 /*----------------------------------------------------------------*/
404 * When a new space map is created that manages its own space. We use
405 * this tiny bootstrap allocator.
407 static void sm_bootstrap_destroy(struct dm_space_map *sm)
411 static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
413 DMERR("boostrap doesn't support extend");
418 static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
420 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
422 return smm->ll.nr_blocks;
425 static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
427 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
429 *count = smm->ll.nr_blocks - smm->begin;
434 static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
437 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
439 return b < smm->begin ? 1 : 0;
442 static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
443 dm_block_t b, int *result)
450 static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
453 DMERR("boostrap doesn't support set_count");
458 static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
460 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
463 * We know the entire device is unused.
465 if (smm->begin == smm->ll.nr_blocks)
473 static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
475 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
477 return add_bop(smm, BOP_INC, b);
480 static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
482 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
484 return add_bop(smm, BOP_DEC, b);
487 static int sm_bootstrap_commit(struct dm_space_map *sm)
492 static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
494 DMERR("boostrap doesn't support root_size");
499 static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
502 DMERR("boostrap doesn't support copy_root");
507 static struct dm_space_map bootstrap_ops = {
508 .destroy = sm_bootstrap_destroy,
509 .extend = sm_bootstrap_extend,
510 .get_nr_blocks = sm_bootstrap_get_nr_blocks,
511 .get_nr_free = sm_bootstrap_get_nr_free,
512 .get_count = sm_bootstrap_get_count,
513 .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
514 .set_count = sm_bootstrap_set_count,
515 .inc_block = sm_bootstrap_inc_block,
516 .dec_block = sm_bootstrap_dec_block,
517 .new_block = sm_bootstrap_new_block,
518 .commit = sm_bootstrap_commit,
519 .root_size = sm_bootstrap_root_size,
520 .copy_root = sm_bootstrap_copy_root
523 /*----------------------------------------------------------------*/
525 struct dm_space_map *dm_sm_metadata_init(void)
527 struct sm_metadata *smm;
529 smm = kmalloc(sizeof(*smm), GFP_KERNEL);
531 return ERR_PTR(-ENOMEM);
533 memcpy(&smm->sm, &ops, sizeof(smm->sm));
538 int dm_sm_metadata_create(struct dm_space_map *sm,
539 struct dm_transaction_manager *tm,
540 dm_block_t nr_blocks,
541 dm_block_t superblock)
545 enum allocation_event ev;
546 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
548 smm->begin = superblock + 1;
549 smm->recursion_count = 0;
550 smm->allocated_this_transaction = 0;
551 smm->nr_uncommitted = 0;
553 memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
555 r = sm_ll_new_metadata(&smm->ll, tm);
559 r = sm_ll_extend(&smm->ll, nr_blocks);
563 memcpy(&smm->sm, &ops, sizeof(smm->sm));
566 * Now we need to update the newly created data structures with the
567 * allocated blocks that they were built from.
569 for (i = superblock; !r && i < smm->begin; i++)
570 r = sm_ll_inc(&smm->ll, i, &ev);
575 return sm_metadata_commit(sm);
578 int dm_sm_metadata_open(struct dm_space_map *sm,
579 struct dm_transaction_manager *tm,
580 void *root_le, size_t len)
583 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
585 r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
590 smm->recursion_count = 0;
591 smm->allocated_this_transaction = 0;
592 smm->nr_uncommitted = 0;
594 memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));