]> git.ipfire.org Git - thirdparty/git.git/blobdiff - commit-graph.c
Merge branch 'ds/commit-graph-merging-fix'
[thirdparty/git.git] / commit-graph.c
index 33b3a2086c9b1659782a096e4efccd8584b2c02a..6f62a0731383293eb7e617f0ecda932d421757fd 100644 (file)
@@ -1,7 +1,5 @@
-#include "cache.h"
-#include "config.h"
-#include "dir.h"
 #include "git-compat-util.h"
+#include "config.h"
 #include "lockfile.h"
 #include "pack.h"
 #include "packfile.h"
@@ -19,6 +17,8 @@
 #include "bloom.h"
 #include "commit-slab.h"
 #include "shallow.h"
+#include "json-writer.h"
+#include "trace2.h"
 
 void git_test_write_commit_graph_or_die(void)
 {
@@ -172,14 +172,21 @@ static char *get_split_graph_filename(struct object_directory *odb,
                       oid_hex);
 }
 
-static char *get_chain_filename(struct object_directory *odb)
+char *get_commit_graph_chain_filename(struct object_directory *odb)
 {
        return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
 }
 
 static uint8_t oid_version(void)
 {
-       return 1;
+       switch (hash_algo_by_ptr(the_hash_algo)) {
+       case GIT_HASH_SHA1:
+               return 1;
+       case GIT_HASH_SHA256:
+               return 2;
+       default:
+               die(_("invalid hash version"));
+       }
 }
 
 static struct commit_graph *alloc_commit_graph(void)
@@ -224,7 +231,8 @@ int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
        return 1;
 }
 
-struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st,
+struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
+                                                int fd, struct stat *st,
                                                 struct object_directory *odb)
 {
        void *graph_map;
@@ -240,7 +248,7 @@ struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st,
        }
        graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
-       ret = parse_commit_graph(graph_map, graph_size);
+       ret = parse_commit_graph(r, graph_map, graph_size);
 
        if (ret)
                ret->odb = odb;
@@ -280,13 +288,13 @@ static int verify_commit_graph_lite(struct commit_graph *g)
        return 0;
 }
 
-struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
+struct commit_graph *parse_commit_graph(struct repository *r,
+                                       void *graph_map, size_t graph_size)
 {
        const unsigned char *data, *chunk_lookup;
        uint32_t i;
        struct commit_graph *graph;
-       uint64_t last_chunk_offset;
-       uint32_t last_chunk_id;
+       uint64_t next_chunk_offset;
        uint32_t graph_signature;
        unsigned char graph_version, hash_version;
 
@@ -319,6 +327,8 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
                return NULL;
        }
 
+       prepare_repo_settings(r);
+
        graph = alloc_commit_graph();
 
        graph->hash_len = the_hash_algo->rawsz;
@@ -326,24 +336,26 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
        graph->data = graph_map;
        graph->data_len = graph_size;
 
-       last_chunk_id = 0;
-       last_chunk_offset = 8;
+       if (graph_size < GRAPH_HEADER_SIZE +
+                        (graph->num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH +
+                        GRAPH_FANOUT_SIZE + the_hash_algo->rawsz) {
+               error(_("commit-graph file is too small to hold %u chunks"),
+                     graph->num_chunks);
+               free(graph);
+               return NULL;
+       }
+
        chunk_lookup = data + 8;
+       next_chunk_offset = get_be64(chunk_lookup + 4);
        for (i = 0; i < graph->num_chunks; i++) {
                uint32_t chunk_id;
-               uint64_t chunk_offset;
+               uint64_t chunk_offset = next_chunk_offset;
                int chunk_repeated = 0;
 
-               if (data + graph_size - chunk_lookup <
-                   GRAPH_CHUNKLOOKUP_WIDTH) {
-                       error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
-                       goto free_and_return;
-               }
-
                chunk_id = get_be32(chunk_lookup + 0);
-               chunk_offset = get_be64(chunk_lookup + 4);
 
                chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
+               next_chunk_offset = get_be64(chunk_lookup + 4);
 
                if (chunk_offset > graph_size - the_hash_algo->rawsz) {
                        error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
@@ -362,8 +374,11 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
                case GRAPH_CHUNKID_OIDLOOKUP:
                        if (graph->chunk_oid_lookup)
                                chunk_repeated = 1;
-                       else
+                       else {
                                graph->chunk_oid_lookup = data + chunk_offset;
+                               graph->num_commits = (next_chunk_offset - chunk_offset)
+                                                    / graph->hash_len;
+                       }
                        break;
 
                case GRAPH_CHUNKID_DATA:
@@ -390,14 +405,14 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
                case GRAPH_CHUNKID_BLOOMINDEXES:
                        if (graph->chunk_bloom_indexes)
                                chunk_repeated = 1;
-                       else
+                       else if (r->settings.commit_graph_read_changed_paths)
                                graph->chunk_bloom_indexes = data + chunk_offset;
                        break;
 
                case GRAPH_CHUNKID_BLOOMDATA:
                        if (graph->chunk_bloom_data)
                                chunk_repeated = 1;
-                       else {
+                       else if (r->settings.commit_graph_read_changed_paths) {
                                uint32_t hash_version;
                                graph->chunk_bloom_data = data + chunk_offset;
                                hash_version = get_be32(data + chunk_offset);
@@ -409,6 +424,7 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
                                graph->bloom_filter_settings->hash_version = hash_version;
                                graph->bloom_filter_settings->num_hashes = get_be32(data + chunk_offset + 4);
                                graph->bloom_filter_settings->bits_per_entry = get_be32(data + chunk_offset + 8);
+                               graph->bloom_filter_settings->max_changed_paths = DEFAULT_BLOOM_MAX_CHANGES;
                        }
                        break;
                }
@@ -417,15 +433,6 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size)
                        error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
                        goto free_and_return;
                }
-
-               if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
-               {
-                       graph->num_commits = (chunk_offset - last_chunk_offset)
-                                            / graph->hash_len;
-               }
-
-               last_chunk_id = chunk_id;
-               last_chunk_offset = chunk_offset;
        }
 
        if (graph->chunk_bloom_indexes && graph->chunk_bloom_data) {
@@ -450,7 +457,8 @@ free_and_return:
        return NULL;
 }
 
-static struct commit_graph *load_commit_graph_one(const char *graph_file,
+static struct commit_graph *load_commit_graph_one(struct repository *r,
+                                                 const char *graph_file,
                                                  struct object_directory *odb)
 {
 
@@ -462,7 +470,7 @@ static struct commit_graph *load_commit_graph_one(const char *graph_file,
        if (!open_ok)
                return NULL;
 
-       g = load_commit_graph_one_fd_st(fd, &st, odb);
+       g = load_commit_graph_one_fd_st(r, fd, &st, odb);
 
        if (g)
                g->filename = xstrdup(graph_file);
@@ -474,7 +482,7 @@ static struct commit_graph *load_commit_graph_v1(struct repository *r,
                                                 struct object_directory *odb)
 {
        char *graph_name = get_commit_graph_filename(odb);
-       struct commit_graph *g = load_commit_graph_one(graph_name, odb);
+       struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
        free(graph_name);
 
        return g;
@@ -521,7 +529,7 @@ static struct commit_graph *load_commit_graph_chain(struct repository *r,
        struct stat st;
        struct object_id *oids;
        int i = 0, valid = 1, count;
-       char *chain_name = get_chain_filename(odb);
+       char *chain_name = get_commit_graph_chain_filename(odb);
        FILE *fp;
        int stat_res;
 
@@ -555,7 +563,7 @@ static struct commit_graph *load_commit_graph_chain(struct repository *r,
                valid = 0;
                for (odb = r->objects->odb; odb; odb = odb->next) {
                        char *graph_name = get_split_graph_filename(odb, line.buf);
-                       struct commit_graph *g = load_commit_graph_one(graph_name, odb);
+                       struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
 
                        free(graph_name);
 
@@ -624,10 +632,6 @@ static int prepare_commit_graph(struct repository *r)
                return !!r->objects->commit_graph;
        r->objects->commit_graph_attempted = 1;
 
-       if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
-               die("dying as requested by the '%s' variable on commit-graph load!",
-                   GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
-
        prepare_repo_settings(r);
 
        if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
@@ -669,6 +673,17 @@ int generation_numbers_enabled(struct repository *r)
        return !!first_generation;
 }
 
+struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r)
+{
+       struct commit_graph *g = r->objects->commit_graph;
+       while (g) {
+               if (g->bloom_filter_settings)
+                       return g->bloom_filter_settings;
+               g = g->base_graph;
+       }
+       return NULL;
+}
+
 static void close_commit_graph_one(struct commit_graph *g)
 {
        if (!g)
@@ -856,6 +871,14 @@ static int parse_commit_in_graph_one(struct repository *r,
 
 int parse_commit_in_graph(struct repository *r, struct commit *item)
 {
+       static int checked_env = 0;
+
+       if (!checked_env &&
+           git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE, 0))
+               die("dying as requested by the '%s' variable on commit-graph parse!",
+                   GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE);
+       checked_env = 1;
+
        if (!prepare_commit_graph(r))
                return 0;
        return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
@@ -946,12 +969,18 @@ struct write_commit_graph_context {
                 changed_paths:1,
                 order_by_pack:1;
 
-       const struct split_commit_graph_opts *split_opts;
+       const struct commit_graph_opts *opts;
        size_t total_bloom_filter_data_size;
+       const struct bloom_filter_settings *bloom_settings;
+
+       int count_bloom_filter_computed;
+       int count_bloom_filter_not_computed;
+       int count_bloom_filter_trunc_empty;
+       int count_bloom_filter_trunc_large;
 };
 
-static void write_graph_chunk_fanout(struct hashfile *f,
-                                    struct write_commit_graph_context *ctx)
+static int write_graph_chunk_fanout(struct hashfile *f,
+                                   struct write_commit_graph_context *ctx)
 {
        int i, count = 0;
        struct commit **list = ctx->commits.list;
@@ -972,17 +1001,21 @@ static void write_graph_chunk_fanout(struct hashfile *f,
 
                hashwrite_be32(f, count);
        }
+
+       return 0;
 }
 
-static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
-                                  struct write_commit_graph_context *ctx)
+static int write_graph_chunk_oids(struct hashfile *f,
+                                 struct write_commit_graph_context *ctx)
 {
        struct commit **list = ctx->commits.list;
        int count;
        for (count = 0; count < ctx->commits.nr; count++, list++) {
                display_progress(ctx->progress, ++ctx->progress_cnt);
-               hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
+               hashwrite(f, (*list)->object.oid.hash, the_hash_algo->rawsz);
        }
+
+       return 0;
 }
 
 static const unsigned char *commit_to_sha1(size_t index, void *table)
@@ -991,8 +1024,8 @@ static const unsigned char *commit_to_sha1(size_t index, void *table)
        return commits[index]->object.oid.hash;
 }
 
-static void write_graph_chunk_data(struct hashfile *f, int hash_len,
-                                  struct write_commit_graph_context *ctx)
+static int write_graph_chunk_data(struct hashfile *f,
+                                 struct write_commit_graph_context *ctx)
 {
        struct commit **list = ctx->commits.list;
        struct commit **last = ctx->commits.list + ctx->commits.nr;
@@ -1009,7 +1042,7 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len,
                        die(_("unable to parse commit %s"),
                                oid_to_hex(&(*list)->object.oid));
                tree = get_commit_tree_oid(*list);
-               hashwrite(f, tree->hash, hash_len);
+               hashwrite(f, tree->hash, the_hash_algo->rawsz);
 
                parent = (*list)->parents;
 
@@ -1089,10 +1122,12 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 
                list++;
        }
+
+       return 0;
 }
 
-static void write_graph_chunk_extra_edges(struct hashfile *f,
-                                         struct write_commit_graph_context *ctx)
+static int write_graph_chunk_extra_edges(struct hashfile *f,
+                                        struct write_commit_graph_context *ctx)
 {
        struct commit **list = ctx->commits.list;
        struct commit **last = ctx->commits.list + ctx->commits.nr;
@@ -1141,41 +1176,68 @@ static void write_graph_chunk_extra_edges(struct hashfile *f,
 
                list++;
        }
+
+       return 0;
 }
 
-static void write_graph_chunk_bloom_indexes(struct hashfile *f,
-                                           struct write_commit_graph_context *ctx)
+static int write_graph_chunk_bloom_indexes(struct hashfile *f,
+                                          struct write_commit_graph_context *ctx)
 {
        struct commit **list = ctx->commits.list;
        struct commit **last = ctx->commits.list + ctx->commits.nr;
        uint32_t cur_pos = 0;
 
        while (list < last) {
-               struct bloom_filter *filter = get_bloom_filter(ctx->r, *list, 0);
-               cur_pos += filter->len;
+               struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
+               size_t len = filter ? filter->len : 0;
+               cur_pos += len;
                display_progress(ctx->progress, ++ctx->progress_cnt);
                hashwrite_be32(f, cur_pos);
                list++;
        }
+
+       return 0;
+}
+
+static void trace2_bloom_filter_settings(struct write_commit_graph_context *ctx)
+{
+       struct json_writer jw = JSON_WRITER_INIT;
+
+       jw_object_begin(&jw, 0);
+       jw_object_intmax(&jw, "hash_version", ctx->bloom_settings->hash_version);
+       jw_object_intmax(&jw, "num_hashes", ctx->bloom_settings->num_hashes);
+       jw_object_intmax(&jw, "bits_per_entry", ctx->bloom_settings->bits_per_entry);
+       jw_object_intmax(&jw, "max_changed_paths", ctx->bloom_settings->max_changed_paths);
+       jw_end(&jw);
+
+       trace2_data_json("bloom", ctx->r, "settings", &jw);
+
+       jw_release(&jw);
 }
 
-static void write_graph_chunk_bloom_data(struct hashfile *f,
-                                        struct write_commit_graph_context *ctx,
-                                        const struct bloom_filter_settings *settings)
+static int write_graph_chunk_bloom_data(struct hashfile *f,
+                                       struct write_commit_graph_context *ctx)
 {
        struct commit **list = ctx->commits.list;
        struct commit **last = ctx->commits.list + ctx->commits.nr;
 
-       hashwrite_be32(f, settings->hash_version);
-       hashwrite_be32(f, settings->num_hashes);
-       hashwrite_be32(f, settings->bits_per_entry);
+       trace2_bloom_filter_settings(ctx);
+
+       hashwrite_be32(f, ctx->bloom_settings->hash_version);
+       hashwrite_be32(f, ctx->bloom_settings->num_hashes);
+       hashwrite_be32(f, ctx->bloom_settings->bits_per_entry);
 
        while (list < last) {
-               struct bloom_filter *filter = get_bloom_filter(ctx->r, *list, 0);
+               struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
+               size_t len = filter ? filter->len : 0;
+
                display_progress(ctx->progress, ++ctx->progress_cnt);
-               hashwrite(f, filter->data, filter->len * sizeof(unsigned char));
+               if (len)
+                       hashwrite(f, filter->data, len * sizeof(unsigned char));
                list++;
        }
+
+       return 0;
 }
 
 static int oid_compare(const void *_a, const void *_b)
@@ -1231,8 +1293,8 @@ static void close_reachable(struct write_commit_graph_context *ctx)
 {
        int i;
        struct commit *commit;
-       enum commit_graph_split_flags flags = ctx->split_opts ?
-               ctx->split_opts->flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
+       enum commit_graph_split_flags flags = ctx->opts ?
+               ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
 
        if (ctx->report_progress)
                ctx->progress = start_delayed_progress(
@@ -1336,11 +1398,24 @@ static void compute_generation_numbers(struct write_commit_graph_context *ctx)
        stop_progress(&ctx->progress);
 }
 
+static void trace2_bloom_filter_write_statistics(struct write_commit_graph_context *ctx)
+{
+       trace2_data_intmax("commit-graph", ctx->r, "filter-computed",
+                          ctx->count_bloom_filter_computed);
+       trace2_data_intmax("commit-graph", ctx->r, "filter-not-computed",
+                          ctx->count_bloom_filter_not_computed);
+       trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-empty",
+                          ctx->count_bloom_filter_trunc_empty);
+       trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-large",
+                          ctx->count_bloom_filter_trunc_large);
+}
+
 static void compute_bloom_filters(struct write_commit_graph_context *ctx)
 {
        int i;
        struct progress *progress = NULL;
        struct commit **sorted_commits;
+       int max_new_filters;
 
        init_bloom_filters();
 
@@ -1357,13 +1432,34 @@ static void compute_bloom_filters(struct write_commit_graph_context *ctx)
        else
                QSORT(sorted_commits, ctx->commits.nr, commit_gen_cmp);
 
+       max_new_filters = ctx->opts && ctx->opts->max_new_filters >= 0 ?
+               ctx->opts->max_new_filters : ctx->commits.nr;
+
        for (i = 0; i < ctx->commits.nr; i++) {
+               enum bloom_filter_computed computed = 0;
                struct commit *c = sorted_commits[i];
-               struct bloom_filter *filter = get_bloom_filter(ctx->r, c, 1);
-               ctx->total_bloom_filter_data_size += sizeof(unsigned char) * filter->len;
+               struct bloom_filter *filter = get_or_compute_bloom_filter(
+                       ctx->r,
+                       c,
+                       ctx->count_bloom_filter_computed < max_new_filters,
+                       ctx->bloom_settings,
+                       &computed);
+               if (computed & BLOOM_COMPUTED) {
+                       ctx->count_bloom_filter_computed++;
+                       if (computed & BLOOM_TRUNC_EMPTY)
+                               ctx->count_bloom_filter_trunc_empty++;
+                       if (computed & BLOOM_TRUNC_LARGE)
+                               ctx->count_bloom_filter_trunc_large++;
+               } else if (computed & BLOOM_NOT_COMPUTED)
+                       ctx->count_bloom_filter_not_computed++;
+               ctx->total_bloom_filter_data_size += filter
+                       ? sizeof(unsigned char) * filter->len : 0;
                display_progress(progress, i + 1);
        }
 
+       if (trace2_is_enabled())
+               trace2_bloom_filter_write_statistics(ctx);
+
        free(sorted_commits);
        stop_progress(&progress);
 }
@@ -1392,7 +1488,7 @@ static int add_ref_to_set(const char *refname,
 
 int write_commit_graph_reachable(struct object_directory *odb,
                                 enum commit_graph_write_flags flags,
-                                const struct split_commit_graph_opts *split_opts)
+                                const struct commit_graph_opts *opts)
 {
        struct oidset commits = OIDSET_INIT;
        struct refs_cb_data data;
@@ -1409,7 +1505,7 @@ int write_commit_graph_reachable(struct object_directory *odb,
        stop_progress(&data.progress);
 
        result = write_commit_graph(odb, NULL, &commits,
-                                   flags, split_opts);
+                                   flags, opts);
 
        oidset_clear(&commits);
        return result;
@@ -1524,8 +1620,8 @@ static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
 {
        uint32_t i;
-       enum commit_graph_split_flags flags = ctx->split_opts ?
-               ctx->split_opts->flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
+       enum commit_graph_split_flags flags = ctx->opts ?
+               ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
 
        ctx->num_extra_edges = 0;
        if (ctx->report_progress)
@@ -1586,19 +1682,27 @@ static int write_graph_chunk_base(struct hashfile *f,
        return 0;
 }
 
+typedef int (*chunk_write_fn)(struct hashfile *f,
+                             struct write_commit_graph_context *ctx);
+
+struct chunk_info {
+       uint32_t id;
+       uint64_t size;
+       chunk_write_fn write_fn;
+};
+
 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 {
        uint32_t i;
        int fd;
        struct hashfile *f;
        struct lock_file lk = LOCK_INIT;
-       uint32_t chunk_ids[MAX_NUM_CHUNKS + 1];
-       uint64_t chunk_offsets[MAX_NUM_CHUNKS + 1];
+       struct chunk_info chunks[MAX_NUM_CHUNKS + 1];
        const unsigned hashsz = the_hash_algo->rawsz;
        struct strbuf progress_title = STRBUF_INIT;
        int num_chunks = 3;
+       uint64_t chunk_offset;
        struct object_id file_hash;
-       const struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
 
        if (ctx->split) {
                struct strbuf tmp_file = STRBUF_INIT;
@@ -1619,7 +1723,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
        }
 
        if (ctx->split) {
-               char *lock_name = get_chain_filename(ctx->odb);
+               char *lock_name = get_commit_graph_chain_filename(ctx->odb);
 
                hold_lock_file_for_update_mode(&lk, lock_name,
                                               LOCK_DIE_ON_ERROR, 0444);
@@ -1644,51 +1748,41 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
                f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
        }
 
-       chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
-       chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
-       chunk_ids[2] = GRAPH_CHUNKID_DATA;
+       chunks[0].id = GRAPH_CHUNKID_OIDFANOUT;
+       chunks[0].size = GRAPH_FANOUT_SIZE;
+       chunks[0].write_fn = write_graph_chunk_fanout;
+       chunks[1].id = GRAPH_CHUNKID_OIDLOOKUP;
+       chunks[1].size = hashsz * ctx->commits.nr;
+       chunks[1].write_fn = write_graph_chunk_oids;
+       chunks[2].id = GRAPH_CHUNKID_DATA;
+       chunks[2].size = (hashsz + 16) * ctx->commits.nr;
+       chunks[2].write_fn = write_graph_chunk_data;
        if (ctx->num_extra_edges) {
-               chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
+               chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
+               chunks[num_chunks].size = 4 * ctx->num_extra_edges;
+               chunks[num_chunks].write_fn = write_graph_chunk_extra_edges;
                num_chunks++;
        }
        if (ctx->changed_paths) {
-               chunk_ids[num_chunks] = GRAPH_CHUNKID_BLOOMINDEXES;
+               chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMINDEXES;
+               chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
+               chunks[num_chunks].write_fn = write_graph_chunk_bloom_indexes;
                num_chunks++;
-               chunk_ids[num_chunks] = GRAPH_CHUNKID_BLOOMDATA;
+               chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMDATA;
+               chunks[num_chunks].size = sizeof(uint32_t) * 3
+                                         + ctx->total_bloom_filter_data_size;
+               chunks[num_chunks].write_fn = write_graph_chunk_bloom_data;
                num_chunks++;
        }
        if (ctx->num_commit_graphs_after > 1) {
-               chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
+               chunks[num_chunks].id = GRAPH_CHUNKID_BASE;
+               chunks[num_chunks].size = hashsz * (ctx->num_commit_graphs_after - 1);
+               chunks[num_chunks].write_fn = write_graph_chunk_base;
                num_chunks++;
        }
 
-       chunk_ids[num_chunks] = 0;
-
-       chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
-       chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
-       chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
-       chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
-
-       num_chunks = 3;
-       if (ctx->num_extra_edges) {
-               chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
-                                               4 * ctx->num_extra_edges;
-               num_chunks++;
-       }
-       if (ctx->changed_paths) {
-               chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
-                                               sizeof(uint32_t) * ctx->commits.nr;
-               num_chunks++;
-
-               chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
-                                               sizeof(uint32_t) * 3 + ctx->total_bloom_filter_data_size;
-               num_chunks++;
-       }
-       if (ctx->num_commit_graphs_after > 1) {
-               chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
-                                               hashsz * (ctx->num_commit_graphs_after - 1);
-               num_chunks++;
-       }
+       chunks[num_chunks].id = 0;
+       chunks[num_chunks].size = 0;
 
        hashwrite_be32(f, GRAPH_SIGNATURE);
 
@@ -1697,13 +1791,16 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
        hashwrite_u8(f, num_chunks);
        hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
 
+       chunk_offset = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
        for (i = 0; i <= num_chunks; i++) {
                uint32_t chunk_write[3];
 
-               chunk_write[0] = htonl(chunk_ids[i]);
-               chunk_write[1] = htonl(chunk_offsets[i] >> 32);
-               chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
+               chunk_write[0] = htonl(chunks[i].id);
+               chunk_write[1] = htonl(chunk_offset >> 32);
+               chunk_write[2] = htonl(chunk_offset & 0xffffffff);
                hashwrite(f, chunk_write, 12);
+
+               chunk_offset += chunks[i].size;
        }
 
        if (ctx->report_progress) {
@@ -1716,19 +1813,19 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
                        progress_title.buf,
                        num_chunks * ctx->commits.nr);
        }
-       write_graph_chunk_fanout(f, ctx);
-       write_graph_chunk_oids(f, hashsz, ctx);
-       write_graph_chunk_data(f, hashsz, ctx);
-       if (ctx->num_extra_edges)
-               write_graph_chunk_extra_edges(f, ctx);
-       if (ctx->changed_paths) {
-               write_graph_chunk_bloom_indexes(f, ctx);
-               write_graph_chunk_bloom_data(f, ctx, &bloom_settings);
-       }
-       if (ctx->num_commit_graphs_after > 1 &&
-           write_graph_chunk_base(f, ctx)) {
-               return -1;
+
+       for (i = 0; i < num_chunks; i++) {
+               uint64_t start_offset = f->total + f->offset;
+
+               if (chunks[i].write_fn(f, ctx))
+                       return -1;
+
+               if (f->total + f->offset != start_offset + chunks[i].size)
+                       BUG("expected to write %"PRId64" bytes to chunk %"PRIx32", but wrote %"PRId64" instead",
+                           chunks[i].size, chunks[i].id,
+                           f->total + f->offset - start_offset);
        }
+
        stop_progress(&ctx->progress);
        strbuf_release(&progress_title);
 
@@ -1809,13 +1906,13 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
        int max_commits = 0;
        int size_mult = 2;
 
-       if (ctx->split_opts) {
-               max_commits = ctx->split_opts->max_commits;
+       if (ctx->opts) {
+               max_commits = ctx->opts->max_commits;
 
-               if (ctx->split_opts->size_multiple)
-                       size_mult = ctx->split_opts->size_multiple;
+               if (ctx->opts->size_multiple)
+                       size_mult = ctx->opts->size_multiple;
 
-               flags = ctx->split_opts->flags;
+               flags = ctx->opts->split_flags;
        }
 
        g = ctx->r->objects->commit_graph;
@@ -2003,10 +2100,10 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx)
        size_t dirnamelen;
        timestamp_t expire_time = time(NULL);
 
-       if (ctx->split_opts && ctx->split_opts->expire_time)
-               expire_time = ctx->split_opts->expire_time;
+       if (ctx->opts && ctx->opts->expire_time)
+               expire_time = ctx->opts->expire_time;
        if (!ctx->split) {
-               char *chain_file_name = get_chain_filename(ctx->odb);
+               char *chain_file_name = get_commit_graph_chain_filename(ctx->odb);
                unlink(chain_file_name);
                free(chain_file_name);
                ctx->num_commit_graphs_after = 0;
@@ -2055,12 +2152,13 @@ int write_commit_graph(struct object_directory *odb,
                       struct string_list *pack_indexes,
                       struct oidset *commits,
                       enum commit_graph_write_flags flags,
-                      const struct split_commit_graph_opts *split_opts)
+                      const struct commit_graph_opts *opts)
 {
        struct write_commit_graph_context *ctx;
        uint32_t i, count_distinct = 0;
        int res = 0;
        int replace = 0;
+       struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
 
        prepare_repo_settings(the_repository);
        if (!the_repository->settings.core_commit_graph) {
@@ -2076,10 +2174,32 @@ int write_commit_graph(struct object_directory *odb,
        ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
        ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
        ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
-       ctx->split_opts = split_opts;
-       ctx->changed_paths = flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS ? 1 : 0;
+       ctx->opts = opts;
        ctx->total_bloom_filter_data_size = 0;
 
+       bloom_settings.bits_per_entry = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_BITS_PER_ENTRY",
+                                                     bloom_settings.bits_per_entry);
+       bloom_settings.num_hashes = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_NUM_HASHES",
+                                                 bloom_settings.num_hashes);
+       bloom_settings.max_changed_paths = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS",
+                                                        bloom_settings.max_changed_paths);
+       ctx->bloom_settings = &bloom_settings;
+
+       if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS)
+               ctx->changed_paths = 1;
+       if (!(flags & COMMIT_GRAPH_NO_WRITE_BLOOM_FILTERS)) {
+               struct commit_graph *g;
+               prepare_commit_graph_one(ctx->r, ctx->odb);
+
+               g = ctx->r->objects->commit_graph;
+
+               /* We have changed-paths already. Keep them in the next graph */
+               if (g && g->chunk_bloom_data) {
+                       ctx->changed_paths = 1;
+                       ctx->bloom_settings = g->bloom_filter_settings;
+               }
+       }
+
        if (ctx->split) {
                struct commit_graph *g;
                prepare_commit_graph(ctx->r);
@@ -2102,15 +2222,15 @@ int write_commit_graph(struct object_directory *odb,
                        }
                }
 
-               if (ctx->split_opts)
-                       replace = ctx->split_opts->flags & COMMIT_GRAPH_SPLIT_REPLACE;
+               if (ctx->opts)
+                       replace = ctx->opts->split_flags & COMMIT_GRAPH_SPLIT_REPLACE;
        }
 
        ctx->approx_nr_objects = approximate_object_count();
        ctx->oids.alloc = ctx->approx_nr_objects / 32;
 
-       if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
-               ctx->oids.alloc = split_opts->max_commits;
+       if (ctx->split && opts && ctx->oids.alloc > opts->max_commits)
+               ctx->oids.alloc = opts->max_commits;
 
        if (ctx->append) {
                prepare_commit_graph_one(ctx->r, ctx->odb);