2 * Copyright (C) 2011 Red Hat, Inc.
4 * This file is released under the GPL.
6 #include "dm-transaction-manager.h"
7 #include "dm-space-map.h"
8 #include "dm-space-map-disk.h"
9 #include "dm-space-map-metadata.h"
10 #include "dm-persistent-data-internal.h"
12 #include <linux/export.h>
13 #include <linux/slab.h>
14 #include <linux/device-mapper.h>
16 #define DM_MSG_PREFIX "transaction manager"
18 /*----------------------------------------------------------------*/
21 struct hlist_node hlist;
26 * It would be nice if we scaled with the size of transaction.
29 #define HASH_MASK (HASH_SIZE - 1)
31 struct dm_transaction_manager {
33 struct dm_transaction_manager *real;
35 struct dm_block_manager *bm;
36 struct dm_space_map *sm;
39 struct hlist_head buckets[HASH_SIZE];
42 /*----------------------------------------------------------------*/
44 static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
47 unsigned bucket = dm_hash_block(b, HASH_MASK);
48 struct shadow_info *si;
52 hlist_for_each_entry(si, n, tm->buckets + bucket, hlist)
57 spin_unlock(&tm->lock);
63 * This can silently fail if there's no memory. We're ok with this since
64 * creating redundant shadows causes no harm.
66 static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b)
69 struct shadow_info *si;
71 si = kmalloc(sizeof(*si), GFP_NOIO);
74 bucket = dm_hash_block(b, HASH_MASK);
76 hlist_add_head(&si->hlist, tm->buckets + bucket);
77 spin_unlock(&tm->lock);
81 static void wipe_shadow_table(struct dm_transaction_manager *tm)
83 struct shadow_info *si;
84 struct hlist_node *n, *tmp;
85 struct hlist_head *bucket;
89 for (i = 0; i < HASH_SIZE; i++) {
90 bucket = tm->buckets + i;
91 hlist_for_each_entry_safe(si, n, tmp, bucket, hlist)
94 INIT_HLIST_HEAD(bucket);
97 spin_unlock(&tm->lock);
100 /*----------------------------------------------------------------*/
102 static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
103 struct dm_space_map *sm)
106 struct dm_transaction_manager *tm;
108 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
110 return ERR_PTR(-ENOMEM);
117 spin_lock_init(&tm->lock);
118 for (i = 0; i < HASH_SIZE; i++)
119 INIT_HLIST_HEAD(tm->buckets + i);
124 struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real)
126 struct dm_transaction_manager *tm;
128 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
136 EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone);
138 void dm_tm_destroy(struct dm_transaction_manager *tm)
141 wipe_shadow_table(tm);
145 EXPORT_SYMBOL_GPL(dm_tm_destroy);
147 int dm_tm_pre_commit(struct dm_transaction_manager *tm)
154 r = dm_sm_commit(tm->sm);
160 EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
162 int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root)
167 wipe_shadow_table(tm);
169 return dm_bm_flush_and_unlock(tm->bm, root);
171 EXPORT_SYMBOL_GPL(dm_tm_commit);
173 int dm_tm_new_block(struct dm_transaction_manager *tm,
174 struct dm_block_validator *v,
175 struct dm_block **result)
178 dm_block_t new_block;
183 r = dm_sm_new_block(tm->sm, &new_block);
187 r = dm_bm_write_lock_zero(tm->bm, new_block, v, result);
189 dm_sm_dec_block(tm->sm, new_block);
194 * New blocks count as shadows in that they don't need to be
197 insert_shadow(tm, new_block);
202 static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
203 struct dm_block_validator *v,
204 struct dm_block **result)
208 struct dm_block *orig_block;
210 r = dm_sm_new_block(tm->sm, &new);
214 r = dm_sm_dec_block(tm->sm, orig);
218 r = dm_bm_read_lock(tm->bm, orig, v, &orig_block);
222 r = dm_bm_unlock_move(orig_block, new);
224 dm_bm_unlock(orig_block);
228 return dm_bm_write_lock(tm->bm, new, v, result);
231 int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
232 struct dm_block_validator *v, struct dm_block **result,
240 r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children);
244 if (is_shadow(tm, orig) && !*inc_children)
245 return dm_bm_write_lock(tm->bm, orig, v, result);
247 r = __shadow_block(tm, orig, v, result);
250 insert_shadow(tm, dm_block_location(*result));
254 EXPORT_SYMBOL_GPL(dm_tm_shadow_block);
256 int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
257 struct dm_block_validator *v,
258 struct dm_block **blk)
261 return dm_bm_read_try_lock(tm->real->bm, b, v, blk);
263 return dm_bm_read_lock(tm->bm, b, v, blk);
265 EXPORT_SYMBOL_GPL(dm_tm_read_lock);
267 int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b)
269 return dm_bm_unlock(b);
271 EXPORT_SYMBOL_GPL(dm_tm_unlock);
273 void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b)
276 * The non-blocking clone doesn't support this.
278 BUG_ON(tm->is_clone);
280 dm_sm_inc_block(tm->sm, b);
282 EXPORT_SYMBOL_GPL(dm_tm_inc);
284 void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b)
287 * The non-blocking clone doesn't support this.
289 BUG_ON(tm->is_clone);
291 dm_sm_dec_block(tm->sm, b);
293 EXPORT_SYMBOL_GPL(dm_tm_dec);
295 int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b,
301 return dm_sm_get_count(tm->sm, b, result);
304 struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
309 /*----------------------------------------------------------------*/
311 static int dm_tm_create_internal(struct dm_block_manager *bm,
312 dm_block_t sb_location,
313 struct dm_block_validator *sb_validator,
314 size_t root_offset, size_t root_max_len,
315 struct dm_transaction_manager **tm,
316 struct dm_space_map **sm,
317 struct dm_block **sblock,
322 *sm = dm_sm_metadata_init();
326 *tm = dm_tm_create(bm, *sm);
333 r = dm_bm_write_lock_zero(dm_tm_get_bm(*tm), sb_location,
334 sb_validator, sblock);
336 DMERR("couldn't lock superblock");
340 r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
343 DMERR("couldn't create metadata space map");
348 r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location,
349 sb_validator, sblock);
351 DMERR("couldn't lock superblock");
355 r = dm_sm_metadata_open(*sm, *tm,
356 dm_block_data(*sblock) + root_offset,
359 DMERR("couldn't open metadata space map");
367 dm_tm_unlock(*tm, *sblock);
373 int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
374 struct dm_block_validator *sb_validator,
375 struct dm_transaction_manager **tm,
376 struct dm_space_map **sm, struct dm_block **sblock)
378 return dm_tm_create_internal(bm, sb_location, sb_validator,
379 0, 0, tm, sm, sblock, 1);
381 EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
383 int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
384 struct dm_block_validator *sb_validator,
385 size_t root_offset, size_t root_max_len,
386 struct dm_transaction_manager **tm,
387 struct dm_space_map **sm, struct dm_block **sblock)
389 return dm_tm_create_internal(bm, sb_location, sb_validator, root_offset,
390 root_max_len, tm, sm, sblock, 0);
392 EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
394 /*----------------------------------------------------------------*/