2 * Copyright (C) 2011-2012 Red Hat, Inc.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "persistent-data/dm-btree.h"
9 #include "persistent-data/dm-space-map.h"
10 #include "persistent-data/dm-space-map-disk.h"
11 #include "persistent-data/dm-transaction-manager.h"
13 #include <linux/list.h>
14 #include <linux/device-mapper.h>
15 #include <linux/workqueue.h>
17 /*--------------------------------------------------------------------------
18 * As far as the metadata goes, there is:
20 * - A superblock in block zero, taking up fewer than 512 bytes for
23 * - A space map managing the metadata blocks.
25 * - A space map managing the data blocks.
27 * - A btree mapping our internal thin dev ids onto struct disk_device_details.
29 * - A hierarchical btree, with 2 levels which effectively maps (thin
30 * dev id, virtual block) -> block_time. Block time is a 64-bit
31 * field holding the time in the low 24 bits, and block in the top 48
34 * BTrees consist solely of btree_nodes, that fill a block. Some are
35 * internal nodes, as such their values are a __le64 pointing to other
36 * nodes. Leaf nodes can store data of any reasonable size (ie. much
37 * smaller than the block size). The nodes consist of the header,
38 * followed by an array of keys, followed by an array of values. We have
39 * to binary search on the keys so they're all held together to help the
42 * Space maps have 2 btrees:
44 * - One maps a uint64_t onto a struct index_entry. Which points to a
45 * bitmap block, and has some details about how many free entries there
48 * - The bitmap blocks have a header (for the checksum). Then the rest
49 * of the block is pairs of bits. With the meaning being:
54 * 3 - ref count is higher than 2
56 * - If the count is higher than 2 then the ref count is entered in a
57 * second btree that directly maps the block_address to a uint32_t ref
60 * The space map metadata variant doesn't have a bitmaps btree. Instead
61 * it has one single blocks worth of index_entries. This avoids
62 * recursive issues with the bitmap btree needing to allocate space in
63 * order to insert. With a small data block size such as 64k the
64 * metadata support data devices that are hundreds of terrabytes.
66 * The space maps allocate space linearly from front to back. Space that
67 * is freed in a transaction is never recycled within that transaction.
68 * To try and avoid fragmenting _free_ space the allocator always goes
69 * back and fills in gaps.
71 * All metadata io is in THIN_METADATA_BLOCK_SIZE sized/aligned chunks
72 * from the block manager.
73 *--------------------------------------------------------------------------*/
75 #define DM_MSG_PREFIX "thin metadata"
77 #define THIN_SUPERBLOCK_MAGIC 27022010
78 #define THIN_SUPERBLOCK_LOCATION 0
79 #define THIN_VERSION 2
80 #define THIN_METADATA_CACHE_SIZE 64
81 #define SECTOR_TO_BLOCK_SHIFT 3
84 * 3 for btree insert +
85 * 2 for btree lookup used within space map
87 #define THIN_MAX_CONCURRENT_LOCKS 5
89 /* This should be plenty */
90 #define SPACE_MAP_ROOT_SIZE 128
93 * Little endian on-disk superblock and device details.
95 struct thin_disk_superblock
{
96 __le32 csum
; /* Checksum of superblock except for this field. */
98 __le64 blocknr
; /* This block number, dm_block_t. */
108 * Root held by userspace transactions.
112 __u8 data_space_map_root
[SPACE_MAP_ROOT_SIZE
];
113 __u8 metadata_space_map_root
[SPACE_MAP_ROOT_SIZE
];
116 * 2-level btree mapping (dev_id, (dev block, time)) -> data block
118 __le64 data_mapping_root
;
121 * Device detail root mapping dev_id -> device_details
123 __le64 device_details_root
;
125 __le32 data_block_size
; /* In 512-byte sectors. */
127 __le32 metadata_block_size
; /* In 512-byte sectors. */
128 __le64 metadata_nr_blocks
;
131 __le32 compat_ro_flags
;
132 __le32 incompat_flags
;
135 struct disk_device_details
{
136 __le64 mapped_blocks
;
137 __le64 transaction_id
; /* When created. */
138 __le32 creation_time
;
139 __le32 snapshotted_time
;
142 struct dm_pool_metadata
{
143 struct hlist_node hash
;
145 struct block_device
*bdev
;
146 struct dm_block_manager
*bm
;
147 struct dm_space_map
*metadata_sm
;
148 struct dm_space_map
*data_sm
;
149 struct dm_transaction_manager
*tm
;
150 struct dm_transaction_manager
*nb_tm
;
154 * First level holds thin_dev_t.
155 * Second level holds mappings.
157 struct dm_btree_info info
;
160 * Non-blocking version of the above.
162 struct dm_btree_info nb_info
;
165 * Just the top level for deleting whole devices.
167 struct dm_btree_info tl_info
;
170 * Just the bottom level for creating new devices.
172 struct dm_btree_info bl_info
;
175 * Describes the device details btree.
177 struct dm_btree_info details_info
;
179 struct rw_semaphore root_lock
;
182 dm_block_t details_root
;
183 struct list_head thin_devices
;
186 sector_t data_block_size
;
190 * Set if a transaction has to be aborted but the attempt to roll back
191 * to the previous (good) transaction failed. The only pool metadata
192 * operation possible in this state is the closing of the device.
197 * Reading the space map roots can fail, so we read it into these
198 * buffers before the superblock is locked and updated.
200 __u8 data_space_map_root
[SPACE_MAP_ROOT_SIZE
];
201 __u8 metadata_space_map_root
[SPACE_MAP_ROOT_SIZE
];
204 struct dm_thin_device
{
205 struct list_head list
;
206 struct dm_pool_metadata
*pmd
;
211 bool aborted_with_changes
:1;
212 uint64_t mapped_blocks
;
213 uint64_t transaction_id
;
214 uint32_t creation_time
;
215 uint32_t snapshotted_time
;
218 /*----------------------------------------------------------------
219 * superblock validator
220 *--------------------------------------------------------------*/
222 #define SUPERBLOCK_CSUM_XOR 160774
224 static void sb_prepare_for_write(struct dm_block_validator
*v
,
228 struct thin_disk_superblock
*disk_super
= dm_block_data(b
);
230 disk_super
->blocknr
= cpu_to_le64(dm_block_location(b
));
231 disk_super
->csum
= cpu_to_le32(dm_bm_checksum(&disk_super
->flags
,
232 block_size
- sizeof(__le32
),
233 SUPERBLOCK_CSUM_XOR
));
236 static int sb_check(struct dm_block_validator
*v
,
240 struct thin_disk_superblock
*disk_super
= dm_block_data(b
);
243 if (dm_block_location(b
) != le64_to_cpu(disk_super
->blocknr
)) {
244 DMERR("sb_check failed: blocknr %llu: "
245 "wanted %llu", le64_to_cpu(disk_super
->blocknr
),
246 (unsigned long long)dm_block_location(b
));
250 if (le64_to_cpu(disk_super
->magic
) != THIN_SUPERBLOCK_MAGIC
) {
251 DMERR("sb_check failed: magic %llu: "
252 "wanted %llu", le64_to_cpu(disk_super
->magic
),
253 (unsigned long long)THIN_SUPERBLOCK_MAGIC
);
257 csum_le
= cpu_to_le32(dm_bm_checksum(&disk_super
->flags
,
258 block_size
- sizeof(__le32
),
259 SUPERBLOCK_CSUM_XOR
));
260 if (csum_le
!= disk_super
->csum
) {
261 DMERR("sb_check failed: csum %u: wanted %u",
262 le32_to_cpu(csum_le
), le32_to_cpu(disk_super
->csum
));
269 static struct dm_block_validator sb_validator
= {
270 .name
= "superblock",
271 .prepare_for_write
= sb_prepare_for_write
,
275 /*----------------------------------------------------------------
276 * Methods for the btree value types
277 *--------------------------------------------------------------*/
279 static uint64_t pack_block_time(dm_block_t b
, uint32_t t
)
281 return (b
<< 24) | t
;
284 static void unpack_block_time(uint64_t v
, dm_block_t
*b
, uint32_t *t
)
287 *t
= v
& ((1 << 24) - 1);
290 static void data_block_inc(void *context
, const void *value_le
)
292 struct dm_space_map
*sm
= context
;
297 memcpy(&v_le
, value_le
, sizeof(v_le
));
298 unpack_block_time(le64_to_cpu(v_le
), &b
, &t
);
299 dm_sm_inc_block(sm
, b
);
302 static void data_block_dec(void *context
, const void *value_le
)
304 struct dm_space_map
*sm
= context
;
309 memcpy(&v_le
, value_le
, sizeof(v_le
));
310 unpack_block_time(le64_to_cpu(v_le
), &b
, &t
);
311 dm_sm_dec_block(sm
, b
);
314 static int data_block_equal(void *context
, const void *value1_le
, const void *value2_le
)
320 memcpy(&v1_le
, value1_le
, sizeof(v1_le
));
321 memcpy(&v2_le
, value2_le
, sizeof(v2_le
));
322 unpack_block_time(le64_to_cpu(v1_le
), &b1
, &t
);
323 unpack_block_time(le64_to_cpu(v2_le
), &b2
, &t
);
328 static void subtree_inc(void *context
, const void *value
)
330 struct dm_btree_info
*info
= context
;
334 memcpy(&root_le
, value
, sizeof(root_le
));
335 root
= le64_to_cpu(root_le
);
336 dm_tm_inc(info
->tm
, root
);
339 static void subtree_dec(void *context
, const void *value
)
341 struct dm_btree_info
*info
= context
;
345 memcpy(&root_le
, value
, sizeof(root_le
));
346 root
= le64_to_cpu(root_le
);
347 if (dm_btree_del(info
, root
))
348 DMERR("btree delete failed\n");
351 static int subtree_equal(void *context
, const void *value1_le
, const void *value2_le
)
354 memcpy(&v1_le
, value1_le
, sizeof(v1_le
));
355 memcpy(&v2_le
, value2_le
, sizeof(v2_le
));
357 return v1_le
== v2_le
;
360 /*----------------------------------------------------------------*/
362 static int superblock_lock_zero(struct dm_pool_metadata
*pmd
,
363 struct dm_block
**sblock
)
365 return dm_bm_write_lock_zero(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
366 &sb_validator
, sblock
);
369 static int superblock_lock(struct dm_pool_metadata
*pmd
,
370 struct dm_block
**sblock
)
372 return dm_bm_write_lock(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
373 &sb_validator
, sblock
);
376 static int __superblock_all_zeroes(struct dm_block_manager
*bm
, int *result
)
381 __le64
*data_le
, zero
= cpu_to_le64(0);
382 unsigned block_size
= dm_bm_block_size(bm
) / sizeof(__le64
);
385 * We can't use a validator here - it may be all zeroes.
387 r
= dm_bm_read_lock(bm
, THIN_SUPERBLOCK_LOCATION
, NULL
, &b
);
391 data_le
= dm_block_data(b
);
393 for (i
= 0; i
< block_size
; i
++) {
394 if (data_le
[i
] != zero
) {
400 return dm_bm_unlock(b
);
403 static void __setup_btree_details(struct dm_pool_metadata
*pmd
)
405 pmd
->info
.tm
= pmd
->tm
;
406 pmd
->info
.levels
= 2;
407 pmd
->info
.value_type
.context
= pmd
->data_sm
;
408 pmd
->info
.value_type
.size
= sizeof(__le64
);
409 pmd
->info
.value_type
.inc
= data_block_inc
;
410 pmd
->info
.value_type
.dec
= data_block_dec
;
411 pmd
->info
.value_type
.equal
= data_block_equal
;
413 memcpy(&pmd
->nb_info
, &pmd
->info
, sizeof(pmd
->nb_info
));
414 pmd
->nb_info
.tm
= pmd
->nb_tm
;
416 pmd
->tl_info
.tm
= pmd
->tm
;
417 pmd
->tl_info
.levels
= 1;
418 pmd
->tl_info
.value_type
.context
= &pmd
->bl_info
;
419 pmd
->tl_info
.value_type
.size
= sizeof(__le64
);
420 pmd
->tl_info
.value_type
.inc
= subtree_inc
;
421 pmd
->tl_info
.value_type
.dec
= subtree_dec
;
422 pmd
->tl_info
.value_type
.equal
= subtree_equal
;
424 pmd
->bl_info
.tm
= pmd
->tm
;
425 pmd
->bl_info
.levels
= 1;
426 pmd
->bl_info
.value_type
.context
= pmd
->data_sm
;
427 pmd
->bl_info
.value_type
.size
= sizeof(__le64
);
428 pmd
->bl_info
.value_type
.inc
= data_block_inc
;
429 pmd
->bl_info
.value_type
.dec
= data_block_dec
;
430 pmd
->bl_info
.value_type
.equal
= data_block_equal
;
432 pmd
->details_info
.tm
= pmd
->tm
;
433 pmd
->details_info
.levels
= 1;
434 pmd
->details_info
.value_type
.context
= NULL
;
435 pmd
->details_info
.value_type
.size
= sizeof(struct disk_device_details
);
436 pmd
->details_info
.value_type
.inc
= NULL
;
437 pmd
->details_info
.value_type
.dec
= NULL
;
438 pmd
->details_info
.value_type
.equal
= NULL
;
441 static int save_sm_roots(struct dm_pool_metadata
*pmd
)
446 r
= dm_sm_root_size(pmd
->metadata_sm
, &len
);
450 r
= dm_sm_copy_root(pmd
->metadata_sm
, &pmd
->metadata_space_map_root
, len
);
454 r
= dm_sm_root_size(pmd
->data_sm
, &len
);
458 return dm_sm_copy_root(pmd
->data_sm
, &pmd
->data_space_map_root
, len
);
461 static void copy_sm_roots(struct dm_pool_metadata
*pmd
,
462 struct thin_disk_superblock
*disk
)
464 memcpy(&disk
->metadata_space_map_root
,
465 &pmd
->metadata_space_map_root
,
466 sizeof(pmd
->metadata_space_map_root
));
468 memcpy(&disk
->data_space_map_root
,
469 &pmd
->data_space_map_root
,
470 sizeof(pmd
->data_space_map_root
));
473 static int __write_initial_superblock(struct dm_pool_metadata
*pmd
)
476 struct dm_block
*sblock
;
477 struct thin_disk_superblock
*disk_super
;
478 sector_t bdev_size
= i_size_read(pmd
->bdev
->bd_inode
) >> SECTOR_SHIFT
;
480 if (bdev_size
> THIN_METADATA_MAX_SECTORS
)
481 bdev_size
= THIN_METADATA_MAX_SECTORS
;
483 r
= dm_sm_commit(pmd
->data_sm
);
487 r
= save_sm_roots(pmd
);
491 r
= dm_tm_pre_commit(pmd
->tm
);
495 r
= superblock_lock_zero(pmd
, &sblock
);
499 disk_super
= dm_block_data(sblock
);
500 disk_super
->flags
= 0;
501 memset(disk_super
->uuid
, 0, sizeof(disk_super
->uuid
));
502 disk_super
->magic
= cpu_to_le64(THIN_SUPERBLOCK_MAGIC
);
503 disk_super
->version
= cpu_to_le32(THIN_VERSION
);
504 disk_super
->time
= 0;
505 disk_super
->trans_id
= 0;
506 disk_super
->held_root
= 0;
508 copy_sm_roots(pmd
, disk_super
);
510 disk_super
->data_mapping_root
= cpu_to_le64(pmd
->root
);
511 disk_super
->device_details_root
= cpu_to_le64(pmd
->details_root
);
512 disk_super
->metadata_block_size
= cpu_to_le32(THIN_METADATA_BLOCK_SIZE
);
513 disk_super
->metadata_nr_blocks
= cpu_to_le64(bdev_size
>> SECTOR_TO_BLOCK_SHIFT
);
514 disk_super
->data_block_size
= cpu_to_le32(pmd
->data_block_size
);
516 return dm_tm_commit(pmd
->tm
, sblock
);
519 static int __format_metadata(struct dm_pool_metadata
*pmd
)
523 r
= dm_tm_create_with_sm(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
524 &pmd
->tm
, &pmd
->metadata_sm
);
526 DMERR("tm_create_with_sm failed");
530 pmd
->data_sm
= dm_sm_disk_create(pmd
->tm
, 0);
531 if (IS_ERR(pmd
->data_sm
)) {
532 DMERR("sm_disk_create failed");
533 r
= PTR_ERR(pmd
->data_sm
);
537 pmd
->nb_tm
= dm_tm_create_non_blocking_clone(pmd
->tm
);
539 DMERR("could not create non-blocking clone tm");
541 goto bad_cleanup_data_sm
;
544 __setup_btree_details(pmd
);
546 r
= dm_btree_empty(&pmd
->info
, &pmd
->root
);
548 goto bad_cleanup_nb_tm
;
550 r
= dm_btree_empty(&pmd
->details_info
, &pmd
->details_root
);
552 DMERR("couldn't create devices root");
553 goto bad_cleanup_nb_tm
;
556 r
= __write_initial_superblock(pmd
);
558 goto bad_cleanup_nb_tm
;
563 dm_tm_destroy(pmd
->nb_tm
);
565 dm_sm_destroy(pmd
->data_sm
);
567 dm_tm_destroy(pmd
->tm
);
568 dm_sm_destroy(pmd
->metadata_sm
);
573 static int __check_incompat_features(struct thin_disk_superblock
*disk_super
,
574 struct dm_pool_metadata
*pmd
)
578 features
= le32_to_cpu(disk_super
->incompat_flags
) & ~THIN_FEATURE_INCOMPAT_SUPP
;
580 DMERR("could not access metadata due to unsupported optional features (%lx).",
581 (unsigned long)features
);
586 * Check for read-only metadata to skip the following RDWR checks.
588 if (get_disk_ro(pmd
->bdev
->bd_disk
))
591 features
= le32_to_cpu(disk_super
->compat_ro_flags
) & ~THIN_FEATURE_COMPAT_RO_SUPP
;
593 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
594 (unsigned long)features
);
601 static int __open_metadata(struct dm_pool_metadata
*pmd
)
604 struct dm_block
*sblock
;
605 struct thin_disk_superblock
*disk_super
;
607 r
= dm_bm_read_lock(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
608 &sb_validator
, &sblock
);
610 DMERR("couldn't read superblock");
614 disk_super
= dm_block_data(sblock
);
616 r
= __check_incompat_features(disk_super
, pmd
);
618 goto bad_unlock_sblock
;
620 r
= dm_tm_open_with_sm(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
621 disk_super
->metadata_space_map_root
,
622 sizeof(disk_super
->metadata_space_map_root
),
623 &pmd
->tm
, &pmd
->metadata_sm
);
625 DMERR("tm_open_with_sm failed");
626 goto bad_unlock_sblock
;
629 pmd
->data_sm
= dm_sm_disk_open(pmd
->tm
, disk_super
->data_space_map_root
,
630 sizeof(disk_super
->data_space_map_root
));
631 if (IS_ERR(pmd
->data_sm
)) {
632 DMERR("sm_disk_open failed");
633 r
= PTR_ERR(pmd
->data_sm
);
637 pmd
->nb_tm
= dm_tm_create_non_blocking_clone(pmd
->tm
);
639 DMERR("could not create non-blocking clone tm");
641 goto bad_cleanup_data_sm
;
644 __setup_btree_details(pmd
);
645 return dm_bm_unlock(sblock
);
648 dm_sm_destroy(pmd
->data_sm
);
650 dm_tm_destroy(pmd
->tm
);
651 dm_sm_destroy(pmd
->metadata_sm
);
653 dm_bm_unlock(sblock
);
658 static int __open_or_format_metadata(struct dm_pool_metadata
*pmd
, bool format_device
)
662 r
= __superblock_all_zeroes(pmd
->bm
, &unformatted
);
667 return format_device
? __format_metadata(pmd
) : -EPERM
;
669 return __open_metadata(pmd
);
672 static int __create_persistent_data_objects(struct dm_pool_metadata
*pmd
, bool format_device
)
676 pmd
->bm
= dm_block_manager_create(pmd
->bdev
, THIN_METADATA_BLOCK_SIZE
<< SECTOR_SHIFT
,
677 THIN_METADATA_CACHE_SIZE
,
678 THIN_MAX_CONCURRENT_LOCKS
);
679 if (IS_ERR(pmd
->bm
)) {
680 DMERR("could not create block manager");
681 return PTR_ERR(pmd
->bm
);
684 r
= __open_or_format_metadata(pmd
, format_device
);
686 dm_block_manager_destroy(pmd
->bm
);
691 static void __destroy_persistent_data_objects(struct dm_pool_metadata
*pmd
)
693 dm_sm_destroy(pmd
->data_sm
);
694 dm_sm_destroy(pmd
->metadata_sm
);
695 dm_tm_destroy(pmd
->nb_tm
);
696 dm_tm_destroy(pmd
->tm
);
697 dm_block_manager_destroy(pmd
->bm
);
700 static int __begin_transaction(struct dm_pool_metadata
*pmd
)
703 struct thin_disk_superblock
*disk_super
;
704 struct dm_block
*sblock
;
707 * We re-read the superblock every time. Shouldn't need to do this
710 r
= dm_bm_read_lock(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
711 &sb_validator
, &sblock
);
715 disk_super
= dm_block_data(sblock
);
716 pmd
->time
= le32_to_cpu(disk_super
->time
);
717 pmd
->root
= le64_to_cpu(disk_super
->data_mapping_root
);
718 pmd
->details_root
= le64_to_cpu(disk_super
->device_details_root
);
719 pmd
->trans_id
= le64_to_cpu(disk_super
->trans_id
);
720 pmd
->flags
= le32_to_cpu(disk_super
->flags
);
721 pmd
->data_block_size
= le32_to_cpu(disk_super
->data_block_size
);
723 dm_bm_unlock(sblock
);
727 static int __write_changed_details(struct dm_pool_metadata
*pmd
)
730 struct dm_thin_device
*td
, *tmp
;
731 struct disk_device_details details
;
734 list_for_each_entry_safe(td
, tmp
, &pmd
->thin_devices
, list
) {
740 details
.mapped_blocks
= cpu_to_le64(td
->mapped_blocks
);
741 details
.transaction_id
= cpu_to_le64(td
->transaction_id
);
742 details
.creation_time
= cpu_to_le32(td
->creation_time
);
743 details
.snapshotted_time
= cpu_to_le32(td
->snapshotted_time
);
744 __dm_bless_for_disk(&details
);
746 r
= dm_btree_insert(&pmd
->details_info
, pmd
->details_root
,
747 &key
, &details
, &pmd
->details_root
);
762 static int __commit_transaction(struct dm_pool_metadata
*pmd
)
765 size_t metadata_len
, data_len
;
766 struct thin_disk_superblock
*disk_super
;
767 struct dm_block
*sblock
;
770 * We need to know if the thin_disk_superblock exceeds a 512-byte sector.
772 BUILD_BUG_ON(sizeof(struct thin_disk_superblock
) > 512);
774 r
= __write_changed_details(pmd
);
778 r
= dm_sm_commit(pmd
->data_sm
);
782 r
= dm_tm_pre_commit(pmd
->tm
);
786 r
= dm_sm_root_size(pmd
->metadata_sm
, &metadata_len
);
790 r
= dm_sm_root_size(pmd
->data_sm
, &data_len
);
794 r
= save_sm_roots(pmd
);
798 r
= superblock_lock(pmd
, &sblock
);
802 disk_super
= dm_block_data(sblock
);
803 disk_super
->time
= cpu_to_le32(pmd
->time
);
804 disk_super
->data_mapping_root
= cpu_to_le64(pmd
->root
);
805 disk_super
->device_details_root
= cpu_to_le64(pmd
->details_root
);
806 disk_super
->trans_id
= cpu_to_le64(pmd
->trans_id
);
807 disk_super
->flags
= cpu_to_le32(pmd
->flags
);
809 copy_sm_roots(pmd
, disk_super
);
811 return dm_tm_commit(pmd
->tm
, sblock
);
814 struct dm_pool_metadata
*dm_pool_metadata_open(struct block_device
*bdev
,
815 sector_t data_block_size
,
819 struct dm_pool_metadata
*pmd
;
821 pmd
= kmalloc(sizeof(*pmd
), GFP_KERNEL
);
823 DMERR("could not allocate metadata struct");
824 return ERR_PTR(-ENOMEM
);
827 init_rwsem(&pmd
->root_lock
);
829 INIT_LIST_HEAD(&pmd
->thin_devices
);
830 pmd
->read_only
= false;
831 pmd
->fail_io
= false;
833 pmd
->data_block_size
= data_block_size
;
835 r
= __create_persistent_data_objects(pmd
, format_device
);
841 r
= __begin_transaction(pmd
);
843 if (dm_pool_metadata_close(pmd
) < 0)
844 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
851 int dm_pool_metadata_close(struct dm_pool_metadata
*pmd
)
854 unsigned open_devices
= 0;
855 struct dm_thin_device
*td
, *tmp
;
857 down_read(&pmd
->root_lock
);
858 list_for_each_entry_safe(td
, tmp
, &pmd
->thin_devices
, list
) {
866 up_read(&pmd
->root_lock
);
869 DMERR("attempt to close pmd when %u device(s) are still open",
874 if (!pmd
->read_only
&& !pmd
->fail_io
) {
875 r
= __commit_transaction(pmd
);
877 DMWARN("%s: __commit_transaction() failed, error = %d",
882 __destroy_persistent_data_objects(pmd
);
889 * __open_device: Returns @td corresponding to device with id @dev,
890 * creating it if @create is set and incrementing @td->open_count.
891 * On failure, @td is undefined.
893 static int __open_device(struct dm_pool_metadata
*pmd
,
894 dm_thin_id dev
, int create
,
895 struct dm_thin_device
**td
)
898 struct dm_thin_device
*td2
;
900 struct disk_device_details details_le
;
903 * If the device is already open, return it.
905 list_for_each_entry(td2
, &pmd
->thin_devices
, list
)
906 if (td2
->id
== dev
) {
908 * May not create an already-open device.
919 * Check the device exists.
921 r
= dm_btree_lookup(&pmd
->details_info
, pmd
->details_root
,
924 if (r
!= -ENODATA
|| !create
)
931 details_le
.mapped_blocks
= 0;
932 details_le
.transaction_id
= cpu_to_le64(pmd
->trans_id
);
933 details_le
.creation_time
= cpu_to_le32(pmd
->time
);
934 details_le
.snapshotted_time
= cpu_to_le32(pmd
->time
);
937 *td
= kmalloc(sizeof(**td
), GFP_NOIO
);
943 (*td
)->open_count
= 1;
944 (*td
)->changed
= changed
;
945 (*td
)->aborted_with_changes
= false;
946 (*td
)->mapped_blocks
= le64_to_cpu(details_le
.mapped_blocks
);
947 (*td
)->transaction_id
= le64_to_cpu(details_le
.transaction_id
);
948 (*td
)->creation_time
= le32_to_cpu(details_le
.creation_time
);
949 (*td
)->snapshotted_time
= le32_to_cpu(details_le
.snapshotted_time
);
951 list_add(&(*td
)->list
, &pmd
->thin_devices
);
956 static void __close_device(struct dm_thin_device
*td
)
961 static int __create_thin(struct dm_pool_metadata
*pmd
,
967 struct disk_device_details details_le
;
968 struct dm_thin_device
*td
;
971 r
= dm_btree_lookup(&pmd
->details_info
, pmd
->details_root
,
977 * Create an empty btree for the mappings.
979 r
= dm_btree_empty(&pmd
->bl_info
, &dev_root
);
984 * Insert it into the main mapping tree.
986 value
= cpu_to_le64(dev_root
);
987 __dm_bless_for_disk(&value
);
988 r
= dm_btree_insert(&pmd
->tl_info
, pmd
->root
, &key
, &value
, &pmd
->root
);
990 dm_btree_del(&pmd
->bl_info
, dev_root
);
994 r
= __open_device(pmd
, dev
, 1, &td
);
996 dm_btree_remove(&pmd
->tl_info
, pmd
->root
, &key
, &pmd
->root
);
997 dm_btree_del(&pmd
->bl_info
, dev_root
);
1005 int dm_pool_create_thin(struct dm_pool_metadata
*pmd
, dm_thin_id dev
)
1009 down_write(&pmd
->root_lock
);
1011 r
= __create_thin(pmd
, dev
);
1012 up_write(&pmd
->root_lock
);
1017 static int __set_snapshot_details(struct dm_pool_metadata
*pmd
,
1018 struct dm_thin_device
*snap
,
1019 dm_thin_id origin
, uint32_t time
)
1022 struct dm_thin_device
*td
;
1024 r
= __open_device(pmd
, origin
, 0, &td
);
1029 td
->snapshotted_time
= time
;
1031 snap
->mapped_blocks
= td
->mapped_blocks
;
1032 snap
->snapshotted_time
= time
;
1038 static int __create_snap(struct dm_pool_metadata
*pmd
,
1039 dm_thin_id dev
, dm_thin_id origin
)
1042 dm_block_t origin_root
;
1043 uint64_t key
= origin
, dev_key
= dev
;
1044 struct dm_thin_device
*td
;
1045 struct disk_device_details details_le
;
1048 /* check this device is unused */
1049 r
= dm_btree_lookup(&pmd
->details_info
, pmd
->details_root
,
1050 &dev_key
, &details_le
);
1054 /* find the mapping tree for the origin */
1055 r
= dm_btree_lookup(&pmd
->tl_info
, pmd
->root
, &key
, &value
);
1058 origin_root
= le64_to_cpu(value
);
1060 /* clone the origin, an inc will do */
1061 dm_tm_inc(pmd
->tm
, origin_root
);
1063 /* insert into the main mapping tree */
1064 value
= cpu_to_le64(origin_root
);
1065 __dm_bless_for_disk(&value
);
1067 r
= dm_btree_insert(&pmd
->tl_info
, pmd
->root
, &key
, &value
, &pmd
->root
);
1069 dm_tm_dec(pmd
->tm
, origin_root
);
1075 r
= __open_device(pmd
, dev
, 1, &td
);
1079 r
= __set_snapshot_details(pmd
, td
, origin
, pmd
->time
);
1088 dm_btree_remove(&pmd
->tl_info
, pmd
->root
, &key
, &pmd
->root
);
1089 dm_btree_remove(&pmd
->details_info
, pmd
->details_root
,
1090 &key
, &pmd
->details_root
);
1094 int dm_pool_create_snap(struct dm_pool_metadata
*pmd
,
1100 down_write(&pmd
->root_lock
);
1102 r
= __create_snap(pmd
, dev
, origin
);
1103 up_write(&pmd
->root_lock
);
1108 static int __delete_device(struct dm_pool_metadata
*pmd
, dm_thin_id dev
)
1112 struct dm_thin_device
*td
;
1114 /* TODO: failure should mark the transaction invalid */
1115 r
= __open_device(pmd
, dev
, 0, &td
);
1119 if (td
->open_count
> 1) {
1124 list_del(&td
->list
);
1126 r
= dm_btree_remove(&pmd
->details_info
, pmd
->details_root
,
1127 &key
, &pmd
->details_root
);
1131 r
= dm_btree_remove(&pmd
->tl_info
, pmd
->root
, &key
, &pmd
->root
);
1138 int dm_pool_delete_thin_device(struct dm_pool_metadata
*pmd
,
1143 down_write(&pmd
->root_lock
);
1145 r
= __delete_device(pmd
, dev
);
1146 up_write(&pmd
->root_lock
);
1151 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata
*pmd
,
1152 uint64_t current_id
,
1157 down_write(&pmd
->root_lock
);
1162 if (pmd
->trans_id
!= current_id
) {
1163 DMERR("mismatched transaction id");
1167 pmd
->trans_id
= new_id
;
1171 up_write(&pmd
->root_lock
);
1176 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata
*pmd
,
1181 down_read(&pmd
->root_lock
);
1182 if (!pmd
->fail_io
) {
1183 *result
= pmd
->trans_id
;
1186 up_read(&pmd
->root_lock
);
1191 static int __reserve_metadata_snap(struct dm_pool_metadata
*pmd
)
1194 struct thin_disk_superblock
*disk_super
;
1195 struct dm_block
*copy
, *sblock
;
1196 dm_block_t held_root
;
1199 * Copy the superblock.
1201 dm_sm_inc_block(pmd
->metadata_sm
, THIN_SUPERBLOCK_LOCATION
);
1202 r
= dm_tm_shadow_block(pmd
->tm
, THIN_SUPERBLOCK_LOCATION
,
1203 &sb_validator
, ©
, &inc
);
1209 held_root
= dm_block_location(copy
);
1210 disk_super
= dm_block_data(copy
);
1212 if (le64_to_cpu(disk_super
->held_root
)) {
1213 DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1215 dm_tm_dec(pmd
->tm
, held_root
);
1216 dm_tm_unlock(pmd
->tm
, copy
);
1221 * Wipe the spacemap since we're not publishing this.
1223 memset(&disk_super
->data_space_map_root
, 0,
1224 sizeof(disk_super
->data_space_map_root
));
1225 memset(&disk_super
->metadata_space_map_root
, 0,
1226 sizeof(disk_super
->metadata_space_map_root
));
1229 * Increment the data structures that need to be preserved.
1231 dm_tm_inc(pmd
->tm
, le64_to_cpu(disk_super
->data_mapping_root
));
1232 dm_tm_inc(pmd
->tm
, le64_to_cpu(disk_super
->device_details_root
));
1233 dm_tm_unlock(pmd
->tm
, copy
);
1236 * Write the held root into the superblock.
1238 r
= superblock_lock(pmd
, &sblock
);
1240 dm_tm_dec(pmd
->tm
, held_root
);
1244 disk_super
= dm_block_data(sblock
);
1245 disk_super
->held_root
= cpu_to_le64(held_root
);
1246 dm_bm_unlock(sblock
);
1250 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata
*pmd
)
1254 down_write(&pmd
->root_lock
);
1256 r
= __reserve_metadata_snap(pmd
);
1257 up_write(&pmd
->root_lock
);
1262 static int __release_metadata_snap(struct dm_pool_metadata
*pmd
)
1265 struct thin_disk_superblock
*disk_super
;
1266 struct dm_block
*sblock
, *copy
;
1267 dm_block_t held_root
;
1269 r
= superblock_lock(pmd
, &sblock
);
1273 disk_super
= dm_block_data(sblock
);
1274 held_root
= le64_to_cpu(disk_super
->held_root
);
1275 disk_super
->held_root
= cpu_to_le64(0);
1277 dm_bm_unlock(sblock
);
1280 DMWARN("No pool metadata snapshot found: nothing to release.");
1284 r
= dm_tm_read_lock(pmd
->tm
, held_root
, &sb_validator
, ©
);
1288 disk_super
= dm_block_data(copy
);
1289 dm_sm_dec_block(pmd
->metadata_sm
, le64_to_cpu(disk_super
->data_mapping_root
));
1290 dm_sm_dec_block(pmd
->metadata_sm
, le64_to_cpu(disk_super
->device_details_root
));
1291 dm_sm_dec_block(pmd
->metadata_sm
, held_root
);
1293 return dm_tm_unlock(pmd
->tm
, copy
);
1296 int dm_pool_release_metadata_snap(struct dm_pool_metadata
*pmd
)
1300 down_write(&pmd
->root_lock
);
1302 r
= __release_metadata_snap(pmd
);
1303 up_write(&pmd
->root_lock
);
1308 static int __get_metadata_snap(struct dm_pool_metadata
*pmd
,
1312 struct thin_disk_superblock
*disk_super
;
1313 struct dm_block
*sblock
;
1315 r
= dm_bm_read_lock(pmd
->bm
, THIN_SUPERBLOCK_LOCATION
,
1316 &sb_validator
, &sblock
);
1320 disk_super
= dm_block_data(sblock
);
1321 *result
= le64_to_cpu(disk_super
->held_root
);
1323 return dm_bm_unlock(sblock
);
1326 int dm_pool_get_metadata_snap(struct dm_pool_metadata
*pmd
,
1331 down_read(&pmd
->root_lock
);
1333 r
= __get_metadata_snap(pmd
, result
);
1334 up_read(&pmd
->root_lock
);
1339 int dm_pool_open_thin_device(struct dm_pool_metadata
*pmd
, dm_thin_id dev
,
1340 struct dm_thin_device
**td
)
1344 down_write(&pmd
->root_lock
);
1346 r
= __open_device(pmd
, dev
, 0, td
);
1347 up_write(&pmd
->root_lock
);
1352 int dm_pool_close_thin_device(struct dm_thin_device
*td
)
1354 down_write(&td
->pmd
->root_lock
);
1356 up_write(&td
->pmd
->root_lock
);
1361 dm_thin_id
dm_thin_dev_id(struct dm_thin_device
*td
)
1367 * Check whether @time (of block creation) is older than @td's last snapshot.
1368 * If so then the associated block is shared with the last snapshot device.
1369 * Any block on a device created *after* the device last got snapshotted is
1370 * necessarily not shared.
1372 static bool __snapshotted_since(struct dm_thin_device
*td
, uint32_t time
)
1374 return td
->snapshotted_time
> time
;
1377 int dm_thin_find_block(struct dm_thin_device
*td
, dm_block_t block
,
1378 int can_block
, struct dm_thin_lookup_result
*result
)
1381 uint64_t block_time
= 0;
1383 struct dm_pool_metadata
*pmd
= td
->pmd
;
1384 dm_block_t keys
[2] = { td
->id
, block
};
1385 struct dm_btree_info
*info
;
1388 down_read(&pmd
->root_lock
);
1390 } else if (down_read_trylock(&pmd
->root_lock
))
1391 info
= &pmd
->nb_info
;
1393 return -EWOULDBLOCK
;
1398 r
= dm_btree_lookup(info
, pmd
->root
, keys
, &value
);
1400 block_time
= le64_to_cpu(value
);
1403 up_read(&pmd
->root_lock
);
1406 dm_block_t exception_block
;
1407 uint32_t exception_time
;
1408 unpack_block_time(block_time
, &exception_block
,
1410 result
->block
= exception_block
;
1411 result
->shared
= __snapshotted_since(td
, exception_time
);
1417 static int __insert(struct dm_thin_device
*td
, dm_block_t block
,
1418 dm_block_t data_block
)
1422 struct dm_pool_metadata
*pmd
= td
->pmd
;
1423 dm_block_t keys
[2] = { td
->id
, block
};
1425 value
= cpu_to_le64(pack_block_time(data_block
, pmd
->time
));
1426 __dm_bless_for_disk(&value
);
1428 r
= dm_btree_insert_notify(&pmd
->info
, pmd
->root
, keys
, &value
,
1429 &pmd
->root
, &inserted
);
1435 td
->mapped_blocks
++;
1440 int dm_thin_insert_block(struct dm_thin_device
*td
, dm_block_t block
,
1441 dm_block_t data_block
)
1445 down_write(&td
->pmd
->root_lock
);
1446 if (!td
->pmd
->fail_io
)
1447 r
= __insert(td
, block
, data_block
);
1448 up_write(&td
->pmd
->root_lock
);
1453 static int __remove(struct dm_thin_device
*td
, dm_block_t block
)
1456 struct dm_pool_metadata
*pmd
= td
->pmd
;
1457 dm_block_t keys
[2] = { td
->id
, block
};
1459 r
= dm_btree_remove(&pmd
->info
, pmd
->root
, keys
, &pmd
->root
);
1463 td
->mapped_blocks
--;
1469 int dm_thin_remove_block(struct dm_thin_device
*td
, dm_block_t block
)
1473 down_write(&td
->pmd
->root_lock
);
1474 if (!td
->pmd
->fail_io
)
1475 r
= __remove(td
, block
);
1476 up_write(&td
->pmd
->root_lock
);
1481 int dm_pool_block_is_used(struct dm_pool_metadata
*pmd
, dm_block_t b
, bool *result
)
1486 down_read(&pmd
->root_lock
);
1487 r
= dm_sm_get_count(pmd
->data_sm
, b
, &ref_count
);
1489 *result
= (ref_count
!= 0);
1490 up_read(&pmd
->root_lock
);
1495 bool dm_thin_changed_this_transaction(struct dm_thin_device
*td
)
1499 down_read(&td
->pmd
->root_lock
);
1501 up_read(&td
->pmd
->root_lock
);
1506 bool dm_pool_changed_this_transaction(struct dm_pool_metadata
*pmd
)
1509 struct dm_thin_device
*td
, *tmp
;
1511 down_read(&pmd
->root_lock
);
1512 list_for_each_entry_safe(td
, tmp
, &pmd
->thin_devices
, list
) {
1518 up_read(&pmd
->root_lock
);
1523 bool dm_thin_aborted_changes(struct dm_thin_device
*td
)
1527 down_read(&td
->pmd
->root_lock
);
1528 r
= td
->aborted_with_changes
;
1529 up_read(&td
->pmd
->root_lock
);
1534 int dm_pool_alloc_data_block(struct dm_pool_metadata
*pmd
, dm_block_t
*result
)
1538 down_write(&pmd
->root_lock
);
1540 r
= dm_sm_new_block(pmd
->data_sm
, result
);
1541 up_write(&pmd
->root_lock
);
1546 int dm_pool_commit_metadata(struct dm_pool_metadata
*pmd
)
1550 down_write(&pmd
->root_lock
);
1554 r
= __commit_transaction(pmd
);
1559 * Open the next transaction.
1561 r
= __begin_transaction(pmd
);
1563 up_write(&pmd
->root_lock
);
1567 static void __set_abort_with_changes_flags(struct dm_pool_metadata
*pmd
)
1569 struct dm_thin_device
*td
;
1571 list_for_each_entry(td
, &pmd
->thin_devices
, list
)
1572 td
->aborted_with_changes
= td
->changed
;
1575 int dm_pool_abort_metadata(struct dm_pool_metadata
*pmd
)
1579 down_write(&pmd
->root_lock
);
1583 __set_abort_with_changes_flags(pmd
);
1584 __destroy_persistent_data_objects(pmd
);
1585 r
= __create_persistent_data_objects(pmd
, false);
1587 pmd
->fail_io
= true;
1590 up_write(&pmd
->root_lock
);
1595 int dm_pool_get_free_block_count(struct dm_pool_metadata
*pmd
, dm_block_t
*result
)
1599 down_read(&pmd
->root_lock
);
1601 r
= dm_sm_get_nr_free(pmd
->data_sm
, result
);
1602 up_read(&pmd
->root_lock
);
1607 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata
*pmd
,
1612 down_read(&pmd
->root_lock
);
1614 r
= dm_sm_get_nr_free(pmd
->metadata_sm
, result
);
1615 up_read(&pmd
->root_lock
);
1620 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata
*pmd
,
1625 down_read(&pmd
->root_lock
);
1627 r
= dm_sm_get_nr_blocks(pmd
->metadata_sm
, result
);
1628 up_read(&pmd
->root_lock
);
1633 int dm_pool_get_data_block_size(struct dm_pool_metadata
*pmd
, sector_t
*result
)
1635 down_read(&pmd
->root_lock
);
1636 *result
= pmd
->data_block_size
;
1637 up_read(&pmd
->root_lock
);
1642 int dm_pool_get_data_dev_size(struct dm_pool_metadata
*pmd
, dm_block_t
*result
)
1646 down_read(&pmd
->root_lock
);
1648 r
= dm_sm_get_nr_blocks(pmd
->data_sm
, result
);
1649 up_read(&pmd
->root_lock
);
1654 int dm_thin_get_mapped_count(struct dm_thin_device
*td
, dm_block_t
*result
)
1657 struct dm_pool_metadata
*pmd
= td
->pmd
;
1659 down_read(&pmd
->root_lock
);
1660 if (!pmd
->fail_io
) {
1661 *result
= td
->mapped_blocks
;
1664 up_read(&pmd
->root_lock
);
1669 static int __highest_block(struct dm_thin_device
*td
, dm_block_t
*result
)
1673 dm_block_t thin_root
;
1674 struct dm_pool_metadata
*pmd
= td
->pmd
;
1676 r
= dm_btree_lookup(&pmd
->tl_info
, pmd
->root
, &td
->id
, &value_le
);
1680 thin_root
= le64_to_cpu(value_le
);
1682 return dm_btree_find_highest_key(&pmd
->bl_info
, thin_root
, result
);
1685 int dm_thin_get_highest_mapped_block(struct dm_thin_device
*td
,
1689 struct dm_pool_metadata
*pmd
= td
->pmd
;
1691 down_read(&pmd
->root_lock
);
1693 r
= __highest_block(td
, result
);
1694 up_read(&pmd
->root_lock
);
1699 static int __resize_space_map(struct dm_space_map
*sm
, dm_block_t new_count
)
1702 dm_block_t old_count
;
1704 r
= dm_sm_get_nr_blocks(sm
, &old_count
);
1708 if (new_count
== old_count
)
1711 if (new_count
< old_count
) {
1712 DMERR("cannot reduce size of space map");
1716 return dm_sm_extend(sm
, new_count
- old_count
);
1719 int dm_pool_resize_data_dev(struct dm_pool_metadata
*pmd
, dm_block_t new_count
)
1723 down_write(&pmd
->root_lock
);
1725 r
= __resize_space_map(pmd
->data_sm
, new_count
);
1726 up_write(&pmd
->root_lock
);
1731 int dm_pool_resize_metadata_dev(struct dm_pool_metadata
*pmd
, dm_block_t new_count
)
1735 down_write(&pmd
->root_lock
);
1737 r
= __resize_space_map(pmd
->metadata_sm
, new_count
);
1738 up_write(&pmd
->root_lock
);
1743 void dm_pool_metadata_read_only(struct dm_pool_metadata
*pmd
)
1745 down_write(&pmd
->root_lock
);
1746 pmd
->read_only
= true;
1747 dm_bm_set_read_only(pmd
->bm
);
1748 up_write(&pmd
->root_lock
);
1751 void dm_pool_metadata_read_write(struct dm_pool_metadata
*pmd
)
1753 down_write(&pmd
->root_lock
);
1754 pmd
->read_only
= false;
1755 dm_bm_set_read_write(pmd
->bm
);
1756 up_write(&pmd
->root_lock
);
1759 int dm_pool_register_metadata_threshold(struct dm_pool_metadata
*pmd
,
1760 dm_block_t threshold
,
1761 dm_sm_threshold_fn fn
,
1766 down_write(&pmd
->root_lock
);
1767 r
= dm_sm_register_threshold_callback(pmd
->metadata_sm
, threshold
, fn
, context
);
1768 up_write(&pmd
->root_lock
);
1773 int dm_pool_metadata_set_needs_check(struct dm_pool_metadata
*pmd
)
1776 struct dm_block
*sblock
;
1777 struct thin_disk_superblock
*disk_super
;
1779 down_write(&pmd
->root_lock
);
1780 pmd
->flags
|= THIN_METADATA_NEEDS_CHECK_FLAG
;
1782 r
= superblock_lock(pmd
, &sblock
);
1784 DMERR("couldn't read superblock");
1788 disk_super
= dm_block_data(sblock
);
1789 disk_super
->flags
= cpu_to_le32(pmd
->flags
);
1791 dm_bm_unlock(sblock
);
1793 up_write(&pmd
->root_lock
);
1797 bool dm_pool_metadata_needs_check(struct dm_pool_metadata
*pmd
)
1801 down_read(&pmd
->root_lock
);
1802 needs_check
= pmd
->flags
& THIN_METADATA_NEEDS_CHECK_FLAG
;
1803 up_read(&pmd
->root_lock
);