Andrew's git - gitweb.git/blob

   1/*
   2 * git gc builtin command
   3 *
   4 * Cleanup unreachable files and optimize the repository.
   5 *
   6 * Copyright (c) 2007 James Bowes
   7 *
   8 * Based on git-gc.sh, which is
   9 *
  10 * Copyright (c) 2006 Shawn O. Pearce
  11 */
  12
  13#include "builtin.h"
  14#include "tempfile.h"
  15#include "lockfile.h"
  16#include "parse-options.h"
  17#include "run-command.h"
  18#include "sigchain.h"
  19#include "argv-array.h"
  20#include "commit.h"
  21
  22#define FAILED_RUN "failed to run %s"
  23
  24static const char * const builtin_gc_usage[] = {
  25        N_("git gc [<options>]"),
  26        NULL
  27};
  28
  29static int pack_refs = 1;
  30static int prune_reflogs = 1;
  31static int aggressive_depth = 50;
  32static int aggressive_window = 250;
  33static int gc_auto_threshold = 6700;
  34static int gc_auto_pack_limit = 50;
  35static int detach_auto = 1;
  36static const char *prune_expire = "2.weeks.ago";
  37static const char *prune_worktrees_expire = "3.months.ago";
  38
  39static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  40static struct argv_array reflog = ARGV_ARRAY_INIT;
  41static struct argv_array repack = ARGV_ARRAY_INIT;
  42static struct argv_array prune = ARGV_ARRAY_INIT;
  43static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  44static struct argv_array rerere = ARGV_ARRAY_INIT;
  45
  46static struct tempfile pidfile;
  47static struct lock_file log_lock;
  48
  49static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
  50
  51static void clean_pack_garbage(void)
  52{
  53        int i;
  54        for (i = 0; i < pack_garbage.nr; i++)
  55                unlink_or_warn(pack_garbage.items[i].string);
  56        string_list_clear(&pack_garbage, 0);
  57}
  58
  59static void report_pack_garbage(unsigned seen_bits, const char *path)
  60{
  61        if (seen_bits == PACKDIR_FILE_IDX)
  62                string_list_append(&pack_garbage, path);
  63}
  64
  65static void git_config_date_string(const char *key, const char **output)
  66{
  67        if (git_config_get_string_const(key, output))
  68                return;
  69        if (strcmp(*output, "now")) {
  70                unsigned long now = approxidate("now");
  71                if (approxidate(*output) >= now)
  72                        git_die_config(key, _("Invalid %s: '%s'"), key, *output);
  73        }
  74}
  75
  76static void process_log_file(void)
  77{
  78        struct stat st;
  79        if (!fstat(get_lock_file_fd(&log_lock), &st) && st.st_size)
  80                commit_lock_file(&log_lock);
  81        else
  82                rollback_lock_file(&log_lock);
  83}
  84
  85static void process_log_file_at_exit(void)
  86{
  87        fflush(stderr);
  88        process_log_file();
  89}
  90
  91static void process_log_file_on_signal(int signo)
  92{
  93        process_log_file();
  94        sigchain_pop(signo);
  95        raise(signo);
  96}
  97
  98static void gc_config(void)
  99{
 100        const char *value;
 101
 102        if (!git_config_get_value("gc.packrefs", &value)) {
 103                if (value && !strcmp(value, "notbare"))
 104                        pack_refs = -1;
 105                else
 106                        pack_refs = git_config_bool("gc.packrefs", value);
 107        }
 108
 109        git_config_get_int("gc.aggressivewindow", &aggressive_window);
 110        git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 111        git_config_get_int("gc.auto", &gc_auto_threshold);
 112        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
 113        git_config_get_bool("gc.autodetach", &detach_auto);
 114        git_config_date_string("gc.pruneexpire", &prune_expire);
 115        git_config_date_string("gc.worktreepruneexpire", &prune_worktrees_expire);
 116        git_config(git_default_config, NULL);
 117}
 118
 119static int too_many_loose_objects(void)
 120{
 121        /*
 122         * Quickly check if a "gc" is needed, by estimating how
 123         * many loose objects there are.  Because SHA-1 is evenly
 124         * distributed, we can check only one and get a reasonable
 125         * estimate.
 126         */
 127        char path[PATH_MAX];
 128        const char *objdir = get_object_directory();
 129        DIR *dir;
 130        struct dirent *ent;
 131        int auto_threshold;
 132        int num_loose = 0;
 133        int needed = 0;
 134
 135        if (gc_auto_threshold <= 0)
 136                return 0;
 137
 138        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 139                warning(_("insanely long object directory %.*s"), 50, objdir);
 140                return 0;
 141        }
 142        dir = opendir(path);
 143        if (!dir)
 144                return 0;
 145
 146        auto_threshold = (gc_auto_threshold + 255) / 256;
 147        while ((ent = readdir(dir)) != NULL) {
 148                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 149                    ent->d_name[38] != '\0')
 150                        continue;
 151                if (++num_loose > auto_threshold) {
 152                        needed = 1;
 153                        break;
 154                }
 155        }
 156        closedir(dir);
 157        return needed;
 158}
 159
 160static int too_many_packs(void)
 161{
 162        struct packed_git *p;
 163        int cnt;
 164
 165        if (gc_auto_pack_limit <= 0)
 166                return 0;
 167
 168        prepare_packed_git();
 169        for (cnt = 0, p = packed_git; p; p = p->next) {
 170                if (!p->pack_local)
 171                        continue;
 172                if (p->pack_keep)
 173                        continue;
 174                /*
 175                 * Perhaps check the size of the pack and count only
 176                 * very small ones here?
 177                 */
 178                cnt++;
 179        }
 180        return gc_auto_pack_limit < cnt;
 181}
 182
 183static void add_repack_all_option(void)
 184{
 185        if (prune_expire && !strcmp(prune_expire, "now"))
 186                argv_array_push(&repack, "-a");
 187        else {
 188                argv_array_push(&repack, "-A");
 189                if (prune_expire)
 190                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 191        }
 192}
 193
 194static int need_to_gc(void)
 195{
 196        /*
 197         * Setting gc.auto to 0 or negative can disable the
 198         * automatic gc.
 199         */
 200        if (gc_auto_threshold <= 0)
 201                return 0;
 202
 203        /*
 204         * If there are too many loose objects, but not too many
 205         * packs, we run "repack -d -l".  If there are too many packs,
 206         * we run "repack -A -d -l".  Otherwise we tell the caller
 207         * there is no need.
 208         */
 209        if (too_many_packs())
 210                add_repack_all_option();
 211        else if (!too_many_loose_objects())
 212                return 0;
 213
 214        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 215                return 0;
 216        return 1;
 217}
 218
 219/* return NULL on success, else hostname running the gc */
 220static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 221{
 222        static struct lock_file lock;
 223        char my_host[128];
 224        struct strbuf sb = STRBUF_INIT;
 225        struct stat st;
 226        uintmax_t pid;
 227        FILE *fp;
 228        int fd;
 229        char *pidfile_path;
 230
 231        if (is_tempfile_active(&pidfile))
 232                /* already locked */
 233                return NULL;
 234
 235        if (gethostname(my_host, sizeof(my_host)))
 236                xsnprintf(my_host, sizeof(my_host), "unknown");
 237
 238        pidfile_path = git_pathdup("gc.pid");
 239        fd = hold_lock_file_for_update(&lock, pidfile_path,
 240                                       LOCK_DIE_ON_ERROR);
 241        if (!force) {
 242                static char locking_host[128];
 243                int should_exit;
 244                fp = fopen(pidfile_path, "r");
 245                memset(locking_host, 0, sizeof(locking_host));
 246                should_exit =
 247                        fp != NULL &&
 248                        !fstat(fileno(fp), &st) &&
 249                        /*
 250                         * 12 hour limit is very generous as gc should
 251                         * never take that long. On the other hand we
 252                         * don't really need a strict limit here,
 253                         * running gc --auto one day late is not a big
 254                         * problem. --force can be used in manual gc
 255                         * after the user verifies that no gc is
 256                         * running.
 257                         */
 258                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 259                        fscanf(fp, "%"SCNuMAX" %127c", &pid, locking_host) == 2 &&
 260                        /* be gentle to concurrent "gc" on remote hosts */
 261                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 262                if (fp != NULL)
 263                        fclose(fp);
 264                if (should_exit) {
 265                        if (fd >= 0)
 266                                rollback_lock_file(&lock);
 267                        *ret_pid = pid;
 268                        free(pidfile_path);
 269                        return locking_host;
 270                }
 271        }
 272
 273        strbuf_addf(&sb, "%"PRIuMAX" %s",
 274                    (uintmax_t) getpid(), my_host);
 275        write_in_full(fd, sb.buf, sb.len);
 276        strbuf_release(&sb);
 277        commit_lock_file(&lock);
 278        register_tempfile(&pidfile, pidfile_path);
 279        free(pidfile_path);
 280        return NULL;
 281}
 282
 283static int report_last_gc_error(void)
 284{
 285        struct strbuf sb = STRBUF_INIT;
 286        int ret;
 287
 288        ret = strbuf_read_file(&sb, git_path("gc.log"), 0);
 289        if (ret > 0)
 290                return error(_("The last gc run reported the following. "
 291                               "Please correct the root cause\n"
 292                               "and remove %s.\n"
 293                               "Automatic cleanup will not be performed "
 294                               "until the file is removed.\n\n"
 295                               "%s"),
 296                             git_path("gc.log"), sb.buf);
 297        strbuf_release(&sb);
 298        return 0;
 299}
 300
 301static int gc_before_repack(void)
 302{
 303        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 304                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 305
 306        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 307                return error(FAILED_RUN, reflog.argv[0]);
 308
 309        pack_refs = 0;
 310        prune_reflogs = 0;
 311        return 0;
 312}
 313
 314int cmd_gc(int argc, const char **argv, const char *prefix)
 315{
 316        int aggressive = 0;
 317        int auto_gc = 0;
 318        int quiet = 0;
 319        int force = 0;
 320        const char *name;
 321        pid_t pid;
 322        int daemonized = 0;
 323
 324        struct option builtin_gc_options[] = {
 325                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 326                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 327                        N_("prune unreferenced objects"),
 328                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 329                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 330                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 331                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 332                OPT_END()
 333        };
 334
 335        if (argc == 2 && !strcmp(argv[1], "-h"))
 336                usage_with_options(builtin_gc_usage, builtin_gc_options);
 337
 338        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 339        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 340        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 341        argv_array_pushl(&prune, "prune", "--expire", NULL);
 342        argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 343        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 344
 345        gc_config();
 346
 347        if (pack_refs < 0)
 348                pack_refs = !is_bare_repository();
 349
 350        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 351                             builtin_gc_usage, 0);
 352        if (argc > 0)
 353                usage_with_options(builtin_gc_usage, builtin_gc_options);
 354
 355        if (aggressive) {
 356                argv_array_push(&repack, "-f");
 357                if (aggressive_depth > 0)
 358                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 359                if (aggressive_window > 0)
 360                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 361        }
 362        if (quiet)
 363                argv_array_push(&repack, "-q");
 364
 365        if (auto_gc) {
 366                /*
 367                 * Auto-gc should be least intrusive as possible.
 368                 */
 369                if (!need_to_gc())
 370                        return 0;
 371                if (!quiet) {
 372                        if (detach_auto)
 373                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 374                        else
 375                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 376                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 377                }
 378                if (detach_auto) {
 379                        if (report_last_gc_error())
 380                                return -1;
 381
 382                        if (gc_before_repack())
 383                                return -1;
 384                        /*
 385                         * failure to daemonize is ok, we'll continue
 386                         * in foreground
 387                         */
 388                        daemonized = !daemonize();
 389                }
 390        } else
 391                add_repack_all_option();
 392
 393        name = lock_repo_for_gc(force, &pid);
 394        if (name) {
 395                if (auto_gc)
 396                        return 0; /* be quiet on --auto */
 397                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 398                    name, (uintmax_t)pid);
 399        }
 400
 401        if (daemonized) {
 402                hold_lock_file_for_update(&log_lock,
 403                                          git_path("gc.log"),
 404                                          LOCK_DIE_ON_ERROR);
 405                dup2(get_lock_file_fd(&log_lock), 2);
 406                sigchain_push_common(process_log_file_on_signal);
 407                atexit(process_log_file_at_exit);
 408        }
 409
 410        if (gc_before_repack())
 411                return -1;
 412
 413        if (!repository_format_precious_objects) {
 414                if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 415                        return error(FAILED_RUN, repack.argv[0]);
 416
 417                if (prune_expire) {
 418                        argv_array_push(&prune, prune_expire);
 419                        if (quiet)
 420                                argv_array_push(&prune, "--no-progress");
 421                        if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 422                                return error(FAILED_RUN, prune.argv[0]);
 423                }
 424        }
 425
 426        if (prune_worktrees_expire) {
 427                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 428                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 429                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 430        }
 431
 432        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 433                return error(FAILED_RUN, rerere.argv[0]);
 434
 435        report_garbage = report_pack_garbage;
 436        reprepare_packed_git();
 437        if (pack_garbage.nr > 0)
 438                clean_pack_garbage();
 439
 440        if (auto_gc && too_many_loose_objects())
 441                warning(_("There are too many unreachable loose objects; "
 442                        "run 'git prune' to remove them."));
 443
 444        return 0;
 445}