diff options
Diffstat (limited to 'drivers/md/persistent-data/dm-btree-spine.c')
| -rw-r--r-- | drivers/md/persistent-data/dm-btree-spine.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c new file mode 100644 index 00000000..d9a7912e --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-spine.c @@ -0,0 +1,244 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree-internal.h" +#include "dm-transaction-manager.h" + +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "btree spine" + +/*----------------------------------------------------------------*/ + +#define BTREE_CSUM_XOR 121107 + +static int node_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size); + +static void node_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct node *n = dm_block_data(b); + struct node_header *h = &n->header; + + h->blocknr = cpu_to_le64(dm_block_location(b)); + h->csum = cpu_to_le32(dm_bm_checksum(&h->flags, + block_size - sizeof(__le32), + BTREE_CSUM_XOR)); + + BUG_ON(node_check(v, b, 4096)); +} + +static int node_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct node *n = dm_block_data(b); + struct node_header *h = &n->header; + size_t value_size; + __le32 csum_disk; + uint32_t flags; + + if (dm_block_location(b) != le64_to_cpu(h->blocknr)) { + DMERR("node_check failed blocknr %llu wanted %llu", + le64_to_cpu(h->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags, + block_size - sizeof(__le32), + BTREE_CSUM_XOR)); + if (csum_disk != h->csum) { + DMERR("node_check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(h->csum)); + return -EILSEQ; + } + + value_size = le32_to_cpu(h->value_size); + + if (sizeof(struct node_header) + + (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) { + DMERR("node_check failed: max_entries too large"); + return -EILSEQ; + } + + if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) { + DMERR("node_check failed, too many entries"); + return -EILSEQ; + } + + /* + * The node must be either INTERNAL or LEAF. + */ + flags = le32_to_cpu(h->flags); + if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) { + DMERR("node_check failed, node is neither INTERNAL or LEAF"); + return -EILSEQ; + } + + return 0; +} + +struct dm_block_validator btree_node_validator = { + .name = "btree_node", + .prepare_for_write = node_prepare_for_write, + .check = node_check +}; + +/*----------------------------------------------------------------*/ + +static int bn_read_lock(struct dm_btree_info *info, dm_block_t b, + struct dm_block **result) +{ + return dm_tm_read_lock(info->tm, b, &btree_node_validator, result); +} + +static int bn_shadow(struct dm_btree_info *info, dm_block_t orig, + struct dm_btree_value_type *vt, + struct dm_block **result) +{ + int r, inc; + + r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator, + result, &inc); + if (!r && inc) + inc_children(info->tm, dm_block_data(*result), vt); + + return r; +} + +int new_block(struct dm_btree_info *info, struct dm_block **result) +{ + return dm_tm_new_block(info->tm, &btree_node_validator, result); +} + +int unlock_block(struct dm_btree_info *info, struct dm_block *b) +{ + return dm_tm_unlock(info->tm, b); +} + +/*----------------------------------------------------------------*/ + +void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info) +{ + s->info = info; + s->count = 0; + s->nodes[0] = NULL; + s->nodes[1] = NULL; +} + +int exit_ro_spine(struct ro_spine *s) +{ + int r = 0, i; + + for (i = 0; i < s->count; i++) { + int r2 = unlock_block(s->info, s->nodes[i]); + if (r2 < 0) + r = r2; + } + + return r; +} + +int ro_step(struct ro_spine *s, dm_block_t new_child) +{ + int r; + + if (s->count == 2) { + r = unlock_block(s->info, s->nodes[0]); + if (r < 0) + return r; + s->nodes[0] = s->nodes[1]; + s->count--; + } + + r = bn_read_lock(s->info, new_child, s->nodes + s->count); + if (!r) + s->count++; + + return r; +} + +struct node *ro_node(struct ro_spine *s) +{ + struct dm_block *block; + + BUG_ON(!s->count); + block = s->nodes[s->count - 1]; + + return dm_block_data(block); +} + +/*----------------------------------------------------------------*/ + +void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info) +{ + s->info = info; + s->count = 0; +} + +int exit_shadow_spine(struct shadow_spine *s) +{ + int r = 0, i; + + for (i = 0; i < s->count; i++) { + int r2 = unlock_block(s->info, s->nodes[i]); + if (r2 < 0) + r = r2; + } + + return r; +} + +int shadow_step(struct shadow_spine *s, dm_block_t b, + struct dm_btree_value_type *vt) +{ + int r; + + if (s->count == 2) { + r = unlock_block(s->info, s->nodes[0]); + if (r < 0) + return r; + s->nodes[0] = s->nodes[1]; + s->count--; + } + + r = bn_shadow(s->info, b, vt, s->nodes + s->count); + if (!r) { + if (!s->count) + s->root = dm_block_location(s->nodes[0]); + + s->count++; + } + + return r; +} + +struct dm_block *shadow_current(struct shadow_spine *s) +{ + BUG_ON(!s->count); + + return s->nodes[s->count - 1]; +} + +struct dm_block *shadow_parent(struct shadow_spine *s) +{ + BUG_ON(s->count != 2); + + return s->count == 2 ? s->nodes[0] : NULL; +} + +int shadow_has_parent(struct shadow_spine *s) +{ + return s->count >= 2; +} + +int shadow_root(struct shadow_spine *s) +{ + return s->root; +} |