From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
As we merge commit-graph files in a commit-graph chain, we should clean
up the files that are no longer used.
This change introduces an 'expiry_window' value to the context, which is
always zero (for now). We then check the modified time of each
graph-{hash}.graph file in the $OBJDIR/info/commit-graphs folder and
unlink the files that are older than the expiry_window.
Since this is always zero, this immediately clears all unused graph
files. We will update the value to match a config setting in a future
change.
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
Documentation/technical/commit-graph.txt | 15 ++++++
commit-graph.c | 69 ++++++++++++++++++++++++
t/t5324-split-commit-graph.sh | 2 +-
3 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt
index 473032e476..aed4350a59 100644
--- a/Documentation/technical/commit-graph.txt
+++ b/Documentation/technical/commit-graph.txt
@@ -266,6 +266,21 @@ The merge strategy values (2 for the size multiple, 64,000 for the maximum
number of commits) could be extracted into config settings for full
flexibility.
+## Deleting graph-{hash} files
+
+After a new tip file is written, some `graph-{hash}` files may no longer
+be part of a chain. It is important to remove these files from disk, eventually.
+The main reason to delay removal is that another process could read the
+`commit-graph-chain` file before it is rewritten, but then look for the
+`graph-{hash}` files after they are deleted.
+
+To allow holding old split commit-graphs for a while after they are unreferenced,
+we update the modified times of the files when they become unreferenced. Then,
+we scan the `$OBJDIR/info/commit-graphs/` directory for `graph-{hash}`
+files whose modified times are older than a given expiry window. This window
+defaults to zero, but can be changed using command-line arguments or a config
+setting.
+
## Chains across multiple object directories
In a repo with alternates, we look for the `commit-graph-chain` file starting
diff --git a/commit-graph.c b/commit-graph.c
index fba705bc51..0cc2ceb349 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -1652,6 +1652,70 @@ static void merge_commit_graphs(struct write_commit_graph_context *ctx)
sort_and_scan_merged_commits(ctx);
}
+static void mark_commit_graphs(struct write_commit_graph_context *ctx)
+{
+ uint32_t i;
+ time_t now = time(NULL);
+
+ for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
+ struct stat st;
+ struct utimbuf updated_time;
+
+ stat(ctx->commit_graph_filenames_before[i], &st);
+
+ updated_time.actime = st.st_atime;
+ updated_time.modtime = now;
+ utime(ctx->commit_graph_filenames_before[i], &updated_time);
+ }
+}
+
+static void expire_commit_graphs(struct write_commit_graph_context *ctx)
+{
+ struct strbuf path = STRBUF_INIT;
+ DIR *dir;
+ struct dirent *de;
+ size_t dirnamelen;
+ time_t expire_time = time(NULL);
+
+ strbuf_addstr(&path, ctx->obj_dir);
+ strbuf_addstr(&path, "/info/commit-graphs");
+ dir = opendir(path.buf);
+
+ if (!dir) {
+ strbuf_release(&path);
+ return;
+ }
+
+ strbuf_addch(&path, '/');
+ dirnamelen = path.len;
+ while ((de = readdir(dir)) != NULL) {
+ struct stat st;
+ uint32_t i, found = 0;
+
+ strbuf_setlen(&path, dirnamelen);
+ strbuf_addstr(&path, de->d_name);
+
+ stat(path.buf, &st);
+
+ if (st.st_mtime > expire_time)
+ continue;
+ if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
+ continue;
+
+ for (i = 0; i < ctx->num_commit_graphs_after; i++) {
+ if (!strcmp(ctx->commit_graph_filenames_after[i],
+ path.buf)) {
+ found = 1;
+ break;
+ }
+ }
+
+ if (!found)
+ unlink(path.buf);
+
+ }
+}
+
int write_commit_graph(const char *obj_dir,
struct string_list *pack_indexes,
struct string_list *commit_hex,
@@ -1764,6 +1828,11 @@ int write_commit_graph(const char *obj_dir,
res = write_commit_graph_file(ctx);
+ if (ctx->split) {
+ mark_commit_graphs(ctx);
+ expire_commit_graphs(ctx);
+ }
+
cleanup:
free(ctx->graph_name);
free(ctx->commits.list);
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 46f0832f68..76068ee407 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -141,7 +141,7 @@ test_expect_success 'add one commit, write a merged graph' '
test_path_is_file $graphdir/commit-graph-chain &&
test_line_count = 2 $graphdir/commit-graph-chain &&
ls $graphdir/graph-*.graph >graph-files &&
- test_line_count = 4 graph-files &&
+ test_line_count = 2 graph-files &&
verify_chain_files_exist $graphdir
'
--
gitgitgadget
