diff options
| -rw-r--r-- | refs/files-backend.c | 214 | ||||
| -rw-r--r-- | refs/packed-backend.c | 462 | ||||
| -rw-r--r-- | refs/packed-backend.h | 17 | ||||
| -rw-r--r-- | refs/refs-internal.h | 1 | ||||
| -rwxr-xr-x | t/t1404-update-ref-errors.sh | 73 |
5 files changed, 551 insertions, 216 deletions
diff --git a/refs/files-backend.c b/refs/files-backend.c index a7cc65d0de..32663a999e 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -1041,11 +1041,17 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r) strbuf_release(&err); } -static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r) +/* + * Prune the loose versions of the references in the linked list + * `*refs_to_prune`, freeing the entries in the list as we go. + */ +static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune) { - while (r) { + while (*refs_to_prune) { + struct ref_to_prune *r = *refs_to_prune; + *refs_to_prune = r->next; prune_ref(refs, r); - r = r->next; + free(r); } } @@ -1084,6 +1090,11 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags) int ok; struct ref_to_prune *refs_to_prune = NULL; struct strbuf err = STRBUF_INIT; + struct ref_transaction *transaction; + + transaction = ref_store_transaction_begin(refs->packed_ref_store, &err); + if (!transaction) + return -1; packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err); @@ -1099,12 +1110,14 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags) continue; /* - * Create an entry in the packed-refs cache equivalent - * to the one from the loose ref cache, except that - * we don't copy the peeled status, because we want it - * to be re-peeled. + * Add a reference creation for this reference to the + * packed-refs transaction: */ - add_packed_ref(refs->packed_ref_store, iter->refname, iter->oid); + if (ref_transaction_update(transaction, iter->refname, + iter->oid->hash, NULL, + REF_NODEREF, NULL, &err)) + die("failure preparing to create packed reference %s: %s", + iter->refname, err.buf); /* Schedule the loose reference for pruning if requested. */ if ((flags & PACK_REFS_PRUNE)) { @@ -1118,11 +1131,14 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags) if (ok != ITER_DONE) die("error while iterating over references"); - if (commit_packed_refs(refs->packed_ref_store, &err)) - die("unable to overwrite old ref-pack file: %s", err.buf); + if (ref_transaction_commit(transaction, &err)) + die("unable to write new packed-refs: %s", err.buf); + + ref_transaction_free(transaction); + packed_refs_unlock(refs->packed_ref_store); - prune_refs(refs, refs_to_prune); + prune_refs(refs, &refs_to_prune); strbuf_release(&err); return 0; } @@ -1141,7 +1157,7 @@ static int files_delete_refs(struct ref_store *ref_store, const char *msg, if (packed_refs_lock(refs->packed_ref_store, 0, &err)) goto error; - if (repack_without_refs(refs->packed_ref_store, refnames, &err)) { + if (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) { packed_refs_unlock(refs->packed_ref_store); goto error; } @@ -2431,13 +2447,22 @@ out: return ret; } +struct files_transaction_backend_data { + struct ref_transaction *packed_transaction; + int packed_refs_locked; +}; + /* * Unlock any references in `transaction` that are still locked, and * mark the transaction closed. */ -static void files_transaction_cleanup(struct ref_transaction *transaction) +static void files_transaction_cleanup(struct files_ref_store *refs, + struct ref_transaction *transaction) { size_t i; + struct files_transaction_backend_data *backend_data = + transaction->backend_data; + struct strbuf err = STRBUF_INIT; for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; @@ -2449,6 +2474,17 @@ static void files_transaction_cleanup(struct ref_transaction *transaction) } } + if (backend_data->packed_transaction && + ref_transaction_abort(backend_data->packed_transaction, &err)) { + error("error aborting transaction: %s", err.buf); + strbuf_release(&err); + } + + if (backend_data->packed_refs_locked) + packed_refs_unlock(refs->packed_ref_store); + + free(backend_data); + transaction->state = REF_TRANSACTION_CLOSED; } @@ -2465,12 +2501,17 @@ static int files_transaction_prepare(struct ref_store *ref_store, char *head_ref = NULL; int head_type; struct object_id head_oid; + struct files_transaction_backend_data *backend_data; + struct ref_transaction *packed_transaction = NULL; assert(err); if (!transaction->nr) goto cleanup; + backend_data = xcalloc(1, sizeof(*backend_data)); + transaction->backend_data = backend_data; + /* * Fail if a refname appears more than once in the * transaction. (If we end up splitting up any updates using @@ -2537,6 +2578,41 @@ static int files_transaction_prepare(struct ref_store *ref_store, head_ref, &affected_refnames, err); if (ret) break; + + if (update->flags & REF_DELETING && + !(update->flags & REF_LOG_ONLY) && + !(update->flags & REF_ISPRUNING)) { + /* + * This reference has to be deleted from + * packed-refs if it exists there. + */ + if (!packed_transaction) { + packed_transaction = ref_store_transaction_begin( + refs->packed_ref_store, err); + if (!packed_transaction) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + + backend_data->packed_transaction = + packed_transaction; + } + + ref_transaction_add_update( + packed_transaction, update->refname, + update->flags & ~REF_HAVE_OLD, + update->new_oid.hash, update->old_oid.hash, + NULL); + } + } + + if (packed_transaction) { + if (packed_refs_lock(refs->packed_ref_store, 0, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + backend_data->packed_refs_locked = 1; + ret = ref_transaction_prepare(packed_transaction, err); } cleanup: @@ -2544,7 +2620,7 @@ cleanup: string_list_clear(&affected_refnames, 0); if (ret) - files_transaction_cleanup(transaction); + files_transaction_cleanup(refs, transaction); else transaction->state = REF_TRANSACTION_PREPARED; @@ -2559,9 +2635,10 @@ static int files_transaction_finish(struct ref_store *ref_store, files_downcast(ref_store, 0, "ref_transaction_finish"); size_t i; int ret = 0; - struct string_list refs_to_delete = STRING_LIST_INIT_NODUP; - struct string_list_item *ref_to_delete; struct strbuf sb = STRBUF_INIT; + struct files_transaction_backend_data *backend_data; + struct ref_transaction *packed_transaction; + assert(err); @@ -2570,6 +2647,9 @@ static int files_transaction_finish(struct ref_store *ref_store, return 0; } + backend_data = transaction->backend_data; + packed_transaction = backend_data->packed_transaction; + /* Perform updates first so live commits remain referenced */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; @@ -2605,7 +2685,44 @@ static int files_transaction_finish(struct ref_store *ref_store, } } } - /* Perform deletes now that updates are safely completed */ + + /* + * Now that updates are safely completed, we can perform + * deletes. First delete the reflogs of any references that + * will be deleted, since (in the unexpected event of an + * error) leaving a reference without a reflog is less bad + * than leaving a reflog without a reference (the latter is a + * mildly invalid repository state): + */ + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + if (update->flags & REF_DELETING && + !(update->flags & REF_LOG_ONLY) && + !(update->flags & REF_ISPRUNING)) { + strbuf_reset(&sb); + files_reflog_path(refs, &sb, update->refname); + if (!unlink_or_warn(sb.buf)) + try_remove_empty_parents(refs, update->refname, + REMOVE_EMPTY_PARENTS_REFLOG); + } + } + + /* + * Perform deletes now that updates are safely completed. + * + * First delete any packed versions of the references, while + * retaining the packed-refs lock: + */ + if (packed_transaction) { + ret = ref_transaction_commit(packed_transaction, err); + ref_transaction_free(packed_transaction); + packed_transaction = NULL; + backend_data->packed_transaction = NULL; + if (ret) + goto cleanup; + } + + /* Now delete the loose versions of the references: */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct ref_lock *lock = update->backend_data; @@ -2623,39 +2740,13 @@ static int files_transaction_finish(struct ref_store *ref_store, } update->flags |= REF_DELETED_LOOSE; } - - if (!(update->flags & REF_ISPRUNING)) - string_list_append(&refs_to_delete, - lock->ref_name); } } - if (packed_refs_lock(refs->packed_ref_store, 0, err)) { - ret = TRANSACTION_GENERIC_ERROR; - goto cleanup; - } - - if (repack_without_refs(refs->packed_ref_store, &refs_to_delete, err)) { - ret = TRANSACTION_GENERIC_ERROR; - packed_refs_unlock(refs->packed_ref_store); - goto cleanup; - } - - packed_refs_unlock(refs->packed_ref_store); - - /* Delete the reflogs of any references that were deleted: */ - for_each_string_list_item(ref_to_delete, &refs_to_delete) { - strbuf_reset(&sb); - files_reflog_path(refs, &sb, ref_to_delete->string); - if (!unlink_or_warn(sb.buf)) - try_remove_empty_parents(refs, ref_to_delete->string, - REMOVE_EMPTY_PARENTS_REFLOG); - } - clear_loose_ref_cache(refs); cleanup: - files_transaction_cleanup(transaction); + files_transaction_cleanup(refs, transaction); for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; @@ -2673,7 +2764,6 @@ cleanup: } strbuf_release(&sb); - string_list_clear(&refs_to_delete, 0); return ret; } @@ -2681,7 +2771,10 @@ static int files_transaction_abort(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) { - files_transaction_cleanup(transaction); + struct files_ref_store *refs = + files_downcast(ref_store, 0, "ref_transaction_abort"); + + files_transaction_cleanup(refs, transaction); return 0; } @@ -2703,6 +2796,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, size_t i; int ret = 0; struct string_list affected_refnames = STRING_LIST_INIT_NODUP; + struct ref_transaction *packed_transaction = NULL; assert(err); @@ -2735,6 +2829,12 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, &affected_refnames)) die("BUG: initial ref transaction called with existing refs"); + packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err); + if (!packed_transaction) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; @@ -2747,6 +2847,15 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, ret = TRANSACTION_NAME_CONFLICT; goto cleanup; } + + /* + * Add a reference creation for this reference to the + * packed-refs transaction: + */ + ref_transaction_add_update(packed_transaction, update->refname, + update->flags & ~REF_HAVE_OLD, + update->new_oid.hash, update->old_oid.hash, + NULL); } if (packed_refs_lock(refs->packed_ref_store, 0, err)) { @@ -2754,21 +2863,14 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, goto cleanup; } - for (i = 0; i < transaction->nr; i++) { - struct ref_update *update = transaction->updates[i]; - - if ((update->flags & REF_HAVE_NEW) && - !is_null_oid(&update->new_oid)) - add_packed_ref(refs->packed_ref_store, update->refname, - &update->new_oid); - } - - if (commit_packed_refs(refs->packed_ref_store, err)) { + if (initial_ref_transaction_commit(packed_transaction, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } cleanup: + if (packed_transaction) + ref_transaction_free(packed_transaction); packed_refs_unlock(refs->packed_ref_store); transaction->state = REF_TRANSACTION_CLOSED; string_list_clear(&affected_refnames, 0); diff --git a/refs/packed-backend.c b/refs/packed-backend.c index 321608a114..3bc47ffd5e 100644 --- a/refs/packed-backend.c +++ b/refs/packed-backend.c @@ -92,19 +92,6 @@ struct ref_store *packed_ref_store_create(const char *path, } /* - * Die if refs is not the main ref store. caller is used in any - * necessary error messages. - */ -static void packed_assert_main_repository(struct packed_ref_store *refs, - const char *caller) -{ - if (refs->store_flags & REF_STORE_MAIN) - return; - - die("BUG: operation %s only allowed for main ref store", caller); -} - -/* * Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is * not a `packed_ref_store`. Also die if `packed_ref_store` doesn't * support at least the flags specified in `required_flags`. `caller` @@ -322,40 +309,6 @@ static struct ref_dir *get_packed_refs(struct packed_ref_store *refs) } /* - * Add or overwrite a reference in the in-memory packed reference - * cache. This may only be called while the packed-refs file is locked - * (see packed_refs_lock()). To actually write the packed-refs file, - * call commit_packed_refs(). - */ -void add_packed_ref(struct ref_store *ref_store, - const char *refname, const struct object_id *oid) -{ - struct packed_ref_store *refs = - packed_downcast(ref_store, REF_STORE_WRITE, - "add_packed_ref"); - struct ref_dir *packed_refs; - struct ref_entry *packed_entry; - - if (!is_lock_file_locked(&refs->lock)) - die("BUG: packed refs not locked"); - - if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) - die("Reference has invalid format: '%s'", refname); - - packed_refs = get_packed_refs(refs); - packed_entry = find_ref_entry(packed_refs, refname); - if (packed_entry) { - /* Overwrite the existing entry: */ - oidcpy(&packed_entry->u.value.oid, oid); - packed_entry->flag = REF_ISPACKED; - oidclr(&packed_entry->u.value.peeled); - } else { - packed_entry = create_ref_entry(refname, oid, REF_ISPACKED); - add_ref_entry(packed_refs, packed_entry); - } -} - -/* * Return the ref_entry for the given refname from the packed * references. If it does not exist, return NULL. */ @@ -525,7 +478,6 @@ int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err) "packed_refs_lock"); static int timeout_configured = 0; static int timeout_value = 1000; - struct packed_ref_cache *packed_ref_cache; if (!timeout_configured) { git_config_get_int("core.packedrefstimeout", &timeout_value); @@ -561,9 +513,11 @@ int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err) */ validate_packed_ref_cache(refs); - packed_ref_cache = get_packed_ref_cache(refs); - /* Increment the reference count to prevent it from being freed: */ - acquire_packed_ref_cache(packed_ref_cache); + /* + * Now make sure that the packed-refs file as it exists in the + * locked state is loaded into the cache: + */ + get_packed_ref_cache(refs); return 0; } @@ -577,7 +531,6 @@ void packed_refs_unlock(struct ref_store *ref_store) if (!is_lock_file_locked(&refs->lock)) die("BUG: packed_refs_unlock() called when not locked"); rollback_lock_file(&refs->lock); - release_packed_ref_cache(refs->cache); } int packed_refs_is_locked(struct ref_store *ref_store) @@ -597,29 +550,35 @@ int packed_refs_is_locked(struct ref_store *ref_store) static const char PACKED_REFS_HEADER[] = "# pack-refs with: peeled fully-peeled \n"; +static int packed_init_db(struct ref_store *ref_store, struct strbuf *err) +{ + /* Nothing to do. */ + return 0; +} + /* - * Write the current version of the packed refs cache from memory to - * disk. The packed-refs file must already be locked for writing (see - * packed_refs_lock()). Return zero on success. On errors, rollback - * the lockfile, write an error message to `err`, and return a nonzero - * value. + * Write the packed-refs from the cache to the packed-refs tempfile, + * incorporating any changes from `updates`. `updates` must be a + * sorted string list whose keys are the refnames and whose util + * values are `struct ref_update *`. On error, rollback the tempfile, + * write an error message to `err`, and return a nonzero value. + * + * The packfile must be locked before calling this function and will + * remain locked when it is done. */ -int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err) +static int write_with_updates(struct packed_ref_store *refs, + struct string_list *updates, + struct strbuf *err) { - struct packed_ref_store *refs = - packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN, - "commit_packed_refs"); - struct packed_ref_cache *packed_ref_cache = - get_packed_ref_cache(refs); + struct ref_iterator *iter = NULL; + size_t i; int ok; - int ret = -1; - struct strbuf sb = STRBUF_INIT; FILE *out; - struct ref_iterator *iter; + struct strbuf sb = STRBUF_INIT; char *packed_refs_path; if (!is_lock_file_locked(&refs->lock)) - die("BUG: commit_packed_refs() called when unlocked"); + die("BUG: write_with_updates() called while unlocked"); /* * If packed-refs is a symlink, we want to overwrite the @@ -628,12 +587,13 @@ int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err) */ packed_refs_path = get_locked_file_path(&refs->lock); strbuf_addf(&sb, "%s.new", packed_refs_path); + free(packed_refs_path); refs->tempfile = create_tempfile(sb.buf); if (!refs->tempfile) { strbuf_addf(err, "unable to create file %s: %s", sb.buf, strerror(errno)); strbuf_release(&sb); - goto out; + return -1; } strbuf_release(&sb); @@ -644,131 +604,286 @@ int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err) goto error; } - if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) { - strbuf_addf(err, "error writing to %s: %s", - get_tempfile_path(refs->tempfile), strerror(errno)); - goto error; - } + if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) + goto write_error; + + /* + * We iterate in parallel through the current list of refs and + * the list of updates, processing an entry from at least one + * of the lists each time through the loop. When the current + * list of refs is exhausted, set iter to NULL. When the list + * of updates is exhausted, leave i set to updates->nr. + */ + iter = packed_ref_iterator_begin(&refs->base, "", + DO_FOR_EACH_INCLUDE_BROKEN); + if ((ok = ref_iterator_advance(iter)) != ITER_OK) + iter = NULL; + + i = 0; - iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0); - while ((ok = ref_iterator_advance(iter)) == ITER_OK) { - struct object_id peeled; - int peel_error = ref_iterator_peel(iter, &peeled); - - if (write_packed_entry(out, iter->refname, iter->oid->hash, - peel_error ? NULL : peeled.hash)) { - strbuf_addf(err, "error writing to %s: %s", - get_tempfile_path(refs->tempfile), - strerror(errno)); - ref_iterator_abort(iter); - goto error; + while (iter || i < updates->nr) { + struct ref_update *update = NULL; + int cmp; + + if (i >= updates->nr) { + cmp = -1; + } else { + update = updates->items[i].util; + + if (!iter) + cmp = +1; + else + cmp = strcmp(iter->refname, update->refname); + } + + if (!cmp) { + /* + * There is both an old value and an update + * for this reference. Check the old value if + * necessary: + */ + if ((update->flags & REF_HAVE_OLD)) { + if (is_null_oid(&update->old_oid)) { + strbuf_addf(err, "cannot update ref '%s': " + "reference already exists", + update->refname); + goto error; + } else if (oidcmp(&update->old_oid, iter->oid)) { + strbuf_addf(err, "cannot update ref '%s': " + "is at %s but expected %s", + update->refname, + oid_to_hex(iter->oid), + oid_to_hex(&update->old_oid)); + goto error; + } + } + + /* Now figure out what to use for the new value: */ + if ((update->flags & REF_HAVE_NEW)) { + /* + * The update takes precedence. Skip + * the iterator over the unneeded + * value. + */ + if ((ok = ref_iterator_advance(iter)) != ITER_OK) + iter = NULL; + cmp = +1; + } else { + /* + * The update doesn't actually want to + * change anything. We're done with it. + */ + i++; + cmp = -1; + } + } else if (cmp > 0) { + /* + * There is no old value but there is an + * update for this reference. Make sure that + * the update didn't expect an existing value: + */ + if ((update->flags & REF_HAVE_OLD) && + !is_null_oid(&update->old_oid)) { + strbuf_addf(err, "cannot update ref '%s': " + "reference is missing but expected %s", + update->refname, + oid_to_hex(&update->old_oid)); + goto error; + } + } + + if (cmp < 0) { + /* Pass the old reference through. */ + + struct object_id peeled; + int peel_error = ref_iterator_peel(iter, &peeled); + + if (write_packed_entry(out, iter->refname, + iter->oid->hash, + peel_error ? NULL : peeled.hash)) + goto write_error; + + if ((ok = ref_iterator_advance(iter)) != ITER_OK) + iter = NULL; + } else if (is_null_oid(&update->new_oid)) { + /* + * The update wants to delete the reference, + * and the reference either didn't exist or we + * have already skipped it. So we're done with + * the update (and don't have to write + * anything). + */ + i++; + } else { + struct object_id peeled; + int peel_error = peel_object(update->new_oid.hash, + peeled.hash); + + if (write_packed_entry(out, update->refname, + update->new_oid.hash, + peel_error ? NULL : peeled.hash)) + goto write_error; + + i++; } } if (ok != ITER_DONE) { - strbuf_addf(err, "unable to rewrite packed-refs file: " + strbuf_addf(err, "unable to write packed-refs file: " "error iterating over old contents"); goto error; } - if (rename_tempfile(&refs->tempfile, packed_refs_path)) { - strbuf_addf(err, "error replacing %s: %s", - refs->path, strerror(errno)); - goto out; + if (close_tempfile_gently(refs->tempfile)) { + strbuf_addf(err, "error closing file %s: %s", + get_tempfile_path(refs->tempfile), + strerror(errno)); + strbuf_release(&sb); + delete_tempfile(&refs->tempfile); + return -1; } - ret = 0; - goto out; + return 0; + +write_error: + strbuf_addf(err, "error writing to %s: %s", + get_tempfile_path(refs->tempfile), strerror(errno)); error: - delete_tempfile(&refs->tempfile); + if (iter) + ref_iterator_abort(iter); -out: - free(packed_refs_path); - return ret; + delete_tempfile(&refs->tempfile); + return -1; } -/* - * Rewrite the packed-refs file, omitting any refs listed in - * 'refnames'. On error, leave packed-refs unchanged, write an error - * message to 'err', and return a nonzero value. The packed refs lock - * must be held when calling this function; it will still be held when - * the function returns. - * - * The refs in 'refnames' needn't be sorted. `err` must not be NULL. - */ -int repack_without_refs(struct ref_store *ref_store, - struct string_list *refnames, struct strbuf *err) +struct packed_transaction_backend_data { + /* True iff the transaction owns the packed-refs lock. */ + int own_lock; + + struct string_list updates; +}; + +static void packed_transaction_cleanup(struct packed_ref_store *refs, + struct ref_transaction *transaction) { - struct packed_ref_store *refs = - packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN, - "repack_without_refs"); - struct ref_dir *packed; - struct string_list_item *refname; - int needs_repacking = 0, removed = 0; + struct packed_transaction_backend_data *data = transaction->backend_data; - packed_assert_main_repository(refs, "repack_without_refs"); - assert(err); + if (data) { + string_list_clear(&data->updates, 0); - if (!is_lock_file_locked(&refs->lock)) - die("BUG: repack_without_refs called without holding lock"); + if (is_tempfile_active(refs->tempfile)) + delete_tempfile(&refs->tempfile); - /* Look for a packed ref */ - for_each_string_list_item(refname, refnames) { - if (get_packed_ref(refs, refname->string)) { - needs_repacking = 1; - break; + if (data->own_lock && is_lock_file_locked(&refs->lock)) { + packed_refs_unlock(&refs->base); + data->own_lock = 0; } - } - /* Avoid locking if we have nothing to do */ - if (!needs_repacking) - return 0; /* no refname exists in packed refs */ - - packed = get_packed_refs(refs); - - /* Remove refnames from the cache */ - for_each_string_list_item(refname, refnames) - if (remove_entry_from_dir(packed, refname->string) != -1) - removed = 1; - if (!removed) { - /* - * All packed entries disappeared while we were - * acquiring the lock. - */ - clear_packed_ref_cache(refs); - return 0; + free(data); + transaction->backend_data = NULL; } - /* Write what remains */ - return commit_packed_refs(&refs->base, err); -} - -static int packed_init_db(struct ref_store *ref_store, struct strbuf *err) -{ - /* Nothing to do. */ - return 0; + transaction->state = REF_TRANSACTION_CLOSED; } static int packed_transaction_prepare(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) { - die("BUG: not implemented yet"); + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, + "ref_transaction_prepare"); + struct packed_transaction_backend_data *data; + size_t i; + int ret = TRANSACTION_GENERIC_ERROR; + + /* + * Note that we *don't* skip transactions with zero updates, + * because such a transaction might be executed for the side + * effect of ensuring that all of the references are peeled. + * If the caller wants to optimize away empty transactions, it + * should do so itself. + */ + + data = xcalloc(1, sizeof(*data)); + string_list_init(&data->updates, 0); + + transaction->backend_data = data; + + /* + * Stick the updates in a string list by refname so that we + * can sort them: + */ + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + struct string_list_item *item = + string_list_append(&data->updates, update->refname); + + /* Store a pointer to update in item->util: */ + item->util = update; + } + string_list_sort(&data->updates); + + if (ref_update_reject_duplicates(&data->updates, err)) + goto failure; + + if (!is_lock_file_locked(&refs->lock)) { + if (packed_refs_lock(ref_store, 0, err)) + goto failure; + data->own_lock = 1; + } + + if (write_with_updates(refs, &data->updates, err)) + goto failure; + + transaction->state = REF_TRANSACTION_PREPARED; + return 0; + +failure: + packed_transaction_cleanup(refs, transaction); + return ret; } static int packed_transaction_abort(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) { - die("BUG: not implemented yet"); + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, + "ref_transaction_abort"); + + packed_transaction_cleanup(refs, transaction); + return 0; } static int packed_transaction_finish(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) { - die("BUG: not implemented yet"); + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, + "ref_transaction_finish"); + int ret = TRANSACTION_GENERIC_ERROR; + char *packed_refs_path; + + packed_refs_path = get_locked_file_path(&refs->lock); + if (rename_tempfile(&refs->tempfile, packed_refs_path)) { + strbuf_addf(err, "error replacing %s: %s", + refs->path, strerror(errno)); + goto cleanup; + } + + clear_packed_ref_cache(refs); + ret = 0; + +cleanup: + free(packed_refs_path); + packed_transaction_cleanup(refs, transaction); + return ret; } static int packed_initial_transaction_commit(struct ref_store *ref_store, @@ -781,7 +896,50 @@ static int packed_initial_transaction_commit(struct ref_store *ref_store, static int packed_delete_refs(struct ref_store *ref_store, const char *msg, struct string_list *refnames, unsigned int flags) { - die("BUG: not implemented yet"); + struct packed_ref_store *refs = + packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs"); + struct strbuf err = STRBUF_INIT; + struct ref_transaction *transaction; + struct string_list_item *item; + int ret; + + (void)refs; /* We need the check above, but don't use the variable */ + + if (!refnames->nr) + return 0; + + /* + * Since we don't check the references' old_oids, the + * individual updates can't fail, so we can pack all of the + * updates into a single transaction. + */ + + transaction = ref_store_transaction_begin(ref_store, &err); + if (!transaction) + return -1; + + for_each_string_list_item(item, refnames) { + if (ref_transaction_delete(transaction, item->string, NULL, + flags, msg, &err)) { + warning(_("could not delete reference %s: %s"), + item->string, err.buf); + strbuf_reset(&err); + } + } + + ret = ref_transaction_commit(transaction, &err); + + if (ret) { + if (refnames->nr == 1) + error(_("could not delete reference %s: %s"), + refnames->items[0].string, err.buf); + else + error(_("could not delete references: %s"), err.buf); + } + + ref_transaction_free(transaction); + strbuf_release(&err); + return ret; } static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags) diff --git a/refs/packed-backend.h b/refs/packed-backend.h index 03b7c1de95..61687e408a 100644 --- a/refs/packed-backend.h +++ b/refs/packed-backend.h @@ -1,6 +1,15 @@ #ifndef REFS_PACKED_BACKEND_H #define REFS_PACKED_BACKEND_H +/* + * Support for storing references in a `packed-refs` file. + * + * Note that this backend doesn't check for D/F conflicts, because it + * doesn't care about them. But usually it should be wrapped in a + * `files_ref_store` that prevents D/F conflicts from being created, + * even among packed refs. + */ + struct ref_store *packed_ref_store_create(const char *path, unsigned int store_flags); @@ -14,12 +23,4 @@ int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err) void packed_refs_unlock(struct ref_store *ref_store); int packed_refs_is_locked(struct ref_store *ref_store); -void add_packed_ref(struct ref_store *ref_store, - const char *refname, const struct object_id *oid); - -int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err); - -int repack_without_refs(struct ref_store *ref_store, - struct string_list *refnames, struct strbuf *err); - #endif /* REFS_PACKED_BACKEND_H */ diff --git a/refs/refs-internal.h b/refs/refs-internal.h index b02dc5a7e3..d7d344de73 100644 --- a/refs/refs-internal.h +++ b/refs/refs-internal.h @@ -242,6 +242,7 @@ struct ref_transaction { size_t alloc; size_t nr; enum ref_transaction_state state; + void *backend_data; }; /* diff --git a/t/t1404-update-ref-errors.sh b/t/t1404-update-ref-errors.sh index c34ece48f5..100d50e362 100755 --- a/t/t1404-update-ref-errors.sh +++ b/t/t1404-update-ref-errors.sh @@ -404,4 +404,77 @@ test_expect_success 'broken reference blocks indirect create' ' test_cmp expected output.err ' +test_expect_success 'no bogus intermediate values during delete' ' + prefix=refs/slow-transaction && + # Set up a reference with differing loose and packed versions: + git update-ref $prefix/foo $C && + git pack-refs --all && + git update-ref $prefix/foo $D && + git for-each-ref $prefix >unchanged && + # Now try to update the reference, but hold the `packed-refs` lock + # for a while to see what happens while the process is blocked: + : >.git/packed-refs.lock && + test_when_finished "rm -f .git/packed-refs.lock" && + { + # Note: the following command is intentionally run in the + # background. We increase the timeout so that `update-ref` + # attempts to acquire the `packed-refs` lock for longer than + # it takes for us to do the check then delete it: + git -c core.packedrefstimeout=3000 update-ref -d $prefix/foo & + } && + pid2=$! && + # Give update-ref plenty of time to get to the point where it tries + # to lock packed-refs: + sleep 1 && + # Make sure that update-ref did not complete despite the lock: + kill -0 $pid2 && + # Verify that the reference still has its old value: + sha1=$(git rev-parse --verify --quiet $prefix/foo || echo undefined) && + case "$sha1" in + $D) + # This is what we hope for; it means that nothing + # user-visible has changed yet. + : ;; + undefined) + # This is not correct; it means the deletion has happened + # already even though update-ref should not have been + # able to acquire the lock yet. + echo "$prefix/foo deleted prematurely" && + break + ;; + $C) + # This value should never be seen. Probably the loose + # reference has been deleted but the packed reference + # is still there: + echo "$prefix/foo incorrectly observed to be C" && + break + ;; + *) + # WTF? + echo "unexpected value observed for $prefix/foo: $sha1" && + break + ;; + esac >out && + rm -f .git/packed-refs.lock && + wait $pid2 && + test_must_be_empty out && + test_must_fail git rev-parse --verify --quiet $prefix/foo +' + +test_expect_success 'delete fails cleanly if packed-refs file is locked' ' + prefix=refs/locked-packed-refs && + # Set up a reference with differing loose and packed versions: + git update-ref $prefix/foo $C && + git pack-refs --all && + git update-ref $prefix/foo $D && + git for-each-ref $prefix >unchanged && + # Now try to delete it while the `packed-refs` lock is held: + : >.git/packed-refs.lock && + test_when_finished "rm -f .git/packed-refs.lock" && + test_must_fail git update-ref -d $prefix/foo >out 2>err && + git for-each-ref $prefix >actual && + test_i18ngrep "Unable to create $Q.*packed-refs.lock$Q: File exists" err && + test_cmp unchanged actual +' + test_done |