diff options
Diffstat (limited to 'drivers/md/persistent-data/dm-space-map-metadata.c')
| -rw-r--r-- | drivers/md/persistent-data/dm-space-map-metadata.c | 596 |
1 files changed, 596 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c new file mode 100644 index 0000000..e89ae5e --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-metadata.c @@ -0,0 +1,596 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map.h" +#include "dm-space-map-common.h" +#include "dm-space-map-metadata.h" + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map metadata" + +/*----------------------------------------------------------------*/ + +/* + * Space map interface. + * + * The low level disk format is written using the standard btree and + * transaction manager. This means that performing disk operations may + * cause us to recurse into the space map in order to allocate new blocks. + * For this reason we have a pool of pre-allocated blocks large enough to + * service any metadata_ll_disk operation. + */ + +/* + * FIXME: we should calculate this based on the size of the device. + * Only the metadata space map needs this functionality. + */ +#define MAX_RECURSIVE_ALLOCATIONS 1024 + +enum block_op_type { + BOP_INC, + BOP_DEC +}; + +struct block_op { + enum block_op_type type; + dm_block_t block; +}; + +struct sm_metadata { + struct dm_space_map sm; + + struct ll_disk ll; + struct ll_disk old_ll; + + dm_block_t begin; + + unsigned recursion_count; + unsigned allocated_this_transaction; + unsigned nr_uncommitted; + struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS]; +}; + +static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b) +{ + struct block_op *op; + + if (smm->nr_uncommitted == MAX_RECURSIVE_ALLOCATIONS) { + DMERR("too many recursive allocations"); + return -ENOMEM; + } + + op = smm->uncommitted + smm->nr_uncommitted++; + op->type = type; + op->block = b; + + return 0; +} + +static int commit_bop(struct sm_metadata *smm, struct block_op *op) +{ + int r = 0; + enum allocation_event ev; + + switch (op->type) { + case BOP_INC: + r = sm_ll_inc(&smm->ll, op->block, &ev); + break; + + case BOP_DEC: + r = sm_ll_dec(&smm->ll, op->block, &ev); + break; + } + + return r; +} + +static void in(struct sm_metadata *smm) +{ + smm->recursion_count++; +} + +static int out(struct sm_metadata *smm) +{ + int r = 0; + + /* + * If we're not recursing then very bad things are happening. + */ + if (!smm->recursion_count) { + DMERR("lost track of recursion depth"); + return -ENOMEM; + } + + if (smm->recursion_count == 1 && smm->nr_uncommitted) { + while (smm->nr_uncommitted && !r) { + smm->nr_uncommitted--; + r = commit_bop(smm, smm->uncommitted + + smm->nr_uncommitted); + if (r) + break; + } + } + + smm->recursion_count--; + + return r; +} + +/* + * When using the out() function above, we often want to combine an error + * code for the operation run in the recursive context with that from + * out(). + */ +static int combine_errors(int r1, int r2) +{ + return r1 ? r1 : r2; +} + +static int recursing(struct sm_metadata *smm) +{ + return smm->recursion_count; +} + +static void sm_metadata_destroy(struct dm_space_map *sm) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + kfree(smm); +} + +static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + DMERR("doesn't support extend"); + return -EINVAL; +} + +static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->ll.nr_blocks; + + return 0; +} + +static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated - + smm->allocated_this_transaction; + + return 0; +} + +static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + int r, i; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + unsigned adjustment = 0; + + /* + * We may have some uncommitted adjustments to add. This list + * should always be really short. + */ + for (i = 0; i < smm->nr_uncommitted; i++) { + struct block_op *op = smm->uncommitted + i; + + if (op->block != b) + continue; + + switch (op->type) { + case BOP_INC: + adjustment++; + break; + + case BOP_DEC: + adjustment--; + break; + } + } + + r = sm_ll_lookup(&smm->ll, b, result); + if (r) + return r; + + *result += adjustment; + + return 0; +} + +static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + int r, i, adjustment = 0; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + uint32_t rc; + + /* + * We may have some uncommitted adjustments to add. This list + * should always be really short. + */ + for (i = 0; i < smm->nr_uncommitted; i++) { + struct block_op *op = smm->uncommitted + i; + + if (op->block != b) + continue; + + switch (op->type) { + case BOP_INC: + adjustment++; + break; + + case BOP_DEC: + adjustment--; + break; + } + } + + if (adjustment > 1) { + *result = 1; + return 0; + } + + r = sm_ll_lookup_bitmap(&smm->ll, b, &rc); + if (r) + return r; + + if (rc == 3) + /* + * We err on the side of caution, and always return true. + */ + *result = 1; + else + *result = rc + adjustment > 1; + + return 0; +} + +static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + int r, r2; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (smm->recursion_count) { + DMERR("cannot recurse set_count()"); + return -EINVAL; + } + + in(smm); + r = sm_ll_insert(&smm->ll, b, count, &ev); + r2 = out(smm); + + return combine_errors(r, r2); +} + +static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (recursing(smm)) + r = add_bop(smm, BOP_INC, b); + else { + in(smm); + r = sm_ll_inc(&smm->ll, b, &ev); + r2 = out(smm); + } + + return combine_errors(r, r2); +} + +static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (recursing(smm)) + r = add_bop(smm, BOP_DEC, b); + else { + in(smm); + r = sm_ll_dec(&smm->ll, b, &ev); + r2 = out(smm); + } + + return combine_errors(r, r2); +} + +static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b); + if (r) + return r; + + smm->begin = *b + 1; + + if (recursing(smm)) + r = add_bop(smm, BOP_INC, *b); + else { + in(smm); + r = sm_ll_inc(&smm->ll, *b, &ev); + r2 = out(smm); + } + + if (!r) + smm->allocated_this_transaction++; + + return combine_errors(r, r2); +} + +static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + int r = sm_metadata_new_block_(sm, b); + if (r) + DMERR("out of metadata space"); + return r; +} + +static int sm_metadata_commit(struct dm_space_map *sm) +{ + int r; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_commit(&smm->ll); + if (r) + return r; + + memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); + smm->begin = 0; + smm->allocated_this_transaction = 0; + + return 0; +} + +static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result) +{ + *result = sizeof(struct disk_sm_root); + + return 0; +} + +static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + struct disk_sm_root root_le; + + root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks); + root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated); + root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root); + root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root); + + if (max < sizeof(root_le)) + return -ENOSPC; + + memcpy(where_le, &root_le, sizeof(root_le)); + + return 0; +} + +static struct dm_space_map ops = { + .destroy = sm_metadata_destroy, + .extend = sm_metadata_extend, + .get_nr_blocks = sm_metadata_get_nr_blocks, + .get_nr_free = sm_metadata_get_nr_free, + .get_count = sm_metadata_get_count, + .count_is_more_than_one = sm_metadata_count_is_more_than_one, + .set_count = sm_metadata_set_count, + .inc_block = sm_metadata_inc_block, + .dec_block = sm_metadata_dec_block, + .new_block = sm_metadata_new_block, + .commit = sm_metadata_commit, + .root_size = sm_metadata_root_size, + .copy_root = sm_metadata_copy_root +}; + +/*----------------------------------------------------------------*/ + +/* + * When a new space map is created that manages its own space. We use + * this tiny bootstrap allocator. + */ +static void sm_bootstrap_destroy(struct dm_space_map *sm) +{ +} + +static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + DMERR("boostrap doesn't support extend"); + + return -EINVAL; +} + +static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return smm->ll.nr_blocks; +} + +static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->ll.nr_blocks - smm->begin; + + return 0; +} + +static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return b < smm->begin ? 1 : 0; +} + +static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + *result = 0; + + return 0; +} + +static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + DMERR("boostrap doesn't support set_count"); + + return -EINVAL; +} + +static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + /* + * We know the entire device is unused. + */ + if (smm->begin == smm->ll.nr_blocks) + return -ENOSPC; + + *b = smm->begin++; + + return 0; +} + +static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return add_bop(smm, BOP_INC, b); +} + +static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return add_bop(smm, BOP_DEC, b); +} + +static int sm_bootstrap_commit(struct dm_space_map *sm) +{ + return 0; +} + +static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result) +{ + DMERR("boostrap doesn't support root_size"); + + return -EINVAL; +} + +static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where, + size_t max) +{ + DMERR("boostrap doesn't support copy_root"); + + return -EINVAL; +} + +static struct dm_space_map bootstrap_ops = { + .destroy = sm_bootstrap_destroy, + .extend = sm_bootstrap_extend, + .get_nr_blocks = sm_bootstrap_get_nr_blocks, + .get_nr_free = sm_bootstrap_get_nr_free, + .get_count = sm_bootstrap_get_count, + .count_is_more_than_one = sm_bootstrap_count_is_more_than_one, + .set_count = sm_bootstrap_set_count, + .inc_block = sm_bootstrap_inc_block, + .dec_block = sm_bootstrap_dec_block, + .new_block = sm_bootstrap_new_block, + .commit = sm_bootstrap_commit, + .root_size = sm_bootstrap_root_size, + .copy_root = sm_bootstrap_copy_root +}; + +/*----------------------------------------------------------------*/ + +struct dm_space_map *dm_sm_metadata_init(void) +{ + struct sm_metadata *smm; + + smm = kmalloc(sizeof(*smm), GFP_KERNEL); + if (!smm) + return ERR_PTR(-ENOMEM); + + memcpy(&smm->sm, &ops, sizeof(smm->sm)); + + return &smm->sm; +} + +int dm_sm_metadata_create(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + dm_block_t nr_blocks, + dm_block_t superblock) +{ + int r; + dm_block_t i; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + smm->begin = superblock + 1; + smm->recursion_count = 0; + smm->allocated_this_transaction = 0; + smm->nr_uncommitted = 0; + + memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm)); + + r = sm_ll_new_metadata(&smm->ll, tm); + if (r) + return r; + + r = sm_ll_extend(&smm->ll, nr_blocks); + if (r) + return r; + + memcpy(&smm->sm, &ops, sizeof(smm->sm)); + + /* + * Now we need to update the newly created data structures with the + * allocated blocks that they were built from. + */ + for (i = superblock; !r && i < smm->begin; i++) + r = sm_ll_inc(&smm->ll, i, &ev); + + if (r) + return r; + + return sm_metadata_commit(sm); +} + +int dm_sm_metadata_open(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_open_metadata(&smm->ll, tm, root_le, len); + if (r) + return r; + + smm->begin = 0; + smm->recursion_count = 0; + smm->allocated_this_transaction = 0; + smm->nr_uncommitted = 0; + + memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); + return 0; +} |
