[PATCH v3 2/2] tmp-objdir: disable ref updates when replacing the primary odb
From: Neeraj Singh via GitGitGadget <hidden>
Date: 2021-12-06 22:05:13
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Neeraj Singh <redacted> When creating a subprocess with a temporary ODB, we set the GIT_QUARANTINE_ENVIRONMENT env var to tell child Git processes not to update refs, since the tmp-objdir may go away. Introduce a similar mechanism for in-process temporary ODBs when we call tmp_objdir_replace_primary_odb. Now both mechanisms set the disable_ref_updates flag on the odb, which is queried by the ref_transaction_prepare function. Peff's test case [1] was invoking ref updates via the cachetextconv setting. That particular code silently does nothing when a ref update is forbidden. See the call to notes_cache_put in fill_textconv where errors are ignored. [1] https://lore.kernel.org/git/YVOn3hDsb5pnxR53@coredump.intra.peff.net/ (local) Reported-by: Jeff King <redacted> Signed-off-by: Neeraj Singh <redacted> Signed-off-by: Junio C Hamano <redacted> --- environment.c | 4 ++++ object-file.c | 6 ++++++ object-store.h | 7 +++++++ refs.c | 2 +- repository.c | 2 ++ repository.h | 1 + 6 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/environment.c b/environment.c
index fe51dfe24d4..a8b64f5194f 100644
--- a/environment.c
+++ b/environment.c@@ -169,6 +169,10 @@ void setup_git_env(const char *git_dir) args.graft_file = getenv_safe(&to_free, GRAFT_ENVIRONMENT); args.index_file = getenv_safe(&to_free, INDEX_ENVIRONMENT); args.alternate_db = getenv_safe(&to_free, ALTERNATE_DB_ENVIRONMENT); + if (getenv(GIT_QUARANTINE_ENVIRONMENT)) { + args.disable_ref_updates = 1; + } + repo_set_gitdir(the_repository, git_dir, &args); strvec_clear(&to_free);
diff --git a/object-file.c b/object-file.c
index 0b6a61aeaff..659ef7623ff 100644
--- a/object-file.c
+++ b/object-file.c@@ -699,6 +699,12 @@ struct object_directory *set_temporary_primary_odb(const char *dir, int will_des */ new_odb = xcalloc(1, sizeof(*new_odb)); new_odb->path = xstrdup(dir); + + /* + * Disable ref updates while a temporary odb is active, since + * the objects in the database may roll back. + */ + new_odb->disable_ref_updates = 1; new_odb->will_destroy = will_destroy; new_odb->next = the_repository->objects->odb; the_repository->objects->odb = new_odb;
diff --git a/object-store.h b/object-store.h
index cb173e69392..6f89482df03 100644
--- a/object-store.h
+++ b/object-store.h@@ -27,6 +27,13 @@ struct object_directory { uint32_t loose_objects_subdir_seen[8]; /* 256 bits */ struct oidtree *loose_objects_cache; + /* + * This is a temporary object store created by the tmp_objdir + * facility. Disable ref updates since the objects in the store + * might be discarded on rollback. + */ + int disable_ref_updates; + /* * This object store is ephemeral, so there is no need to fsync. */
diff --git a/refs.c b/refs.c
index d7cc0a23a3b..ac744e85f5f 100644
--- a/refs.c
+++ b/refs.c@@ -2137,7 +2137,7 @@ int ref_transaction_prepare(struct ref_transaction *transaction, break; } - if (getenv(GIT_QUARANTINE_ENVIRONMENT)) { + if (refs->repo->objects->odb->disable_ref_updates) { strbuf_addstr(err, _("ref updates forbidden inside quarantine environment")); return -1;
diff --git a/repository.c b/repository.c
index c5b90ba93ea..dce8e35ac20 100644
--- a/repository.c
+++ b/repository.c@@ -80,6 +80,8 @@ void repo_set_gitdir(struct repository *repo, expand_base_dir(&repo->objects->odb->path, o->object_dir, repo->commondir, "objects"); + repo->objects->odb->disable_ref_updates = o->disable_ref_updates; + free(repo->objects->alternate_db); repo->objects->alternate_db = xstrdup_or_null(o->alternate_db); expand_base_dir(&repo->graft_file, o->graft_file,
diff --git a/repository.h b/repository.h
index a057653981c..7c04e99ac5c 100644
--- a/repository.h
+++ b/repository.h@@ -158,6 +158,7 @@ struct set_gitdir_args { const char *graft_file; const char *index_file; const char *alternate_db; + int disable_ref_updates; }; void repo_set_gitdir(struct repository *repo, const char *root,
--
gitgitgadget