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 000000000000..e89ae5e7a519
--- /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;
+}