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 "config.h"
  15#include "tempfile.h"
  16#include "lockfile.h"
  17#include "parse-options.h"
  18#include "run-command.h"
  19#include "sigchain.h"
  20#include "argv-array.h"
  21#include "commit.h"
  22
  23#define FAILED_RUN "failed to run %s"
  24
  25static const char * const builtin_gc_usage[] = {
  26        N_("git gc [<options>]"),
  27        NULL
  28};
  29
  30static int pack_refs = 1;
  31static int prune_reflogs = 1;
  32static int aggressive_depth = 50;
  33static int aggressive_window = 250;
  34static int gc_auto_threshold = 6700;
  35static int gc_auto_pack_limit = 50;
  36static int detach_auto = 1;
  37static timestamp_t gc_log_expire_time;
  38static const char *gc_log_expire = "1.day.ago";
  39static const char *prune_expire = "2.weeks.ago";
  40static const char *prune_worktrees_expire = "3.months.ago";
  41
  42static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  43static struct argv_array reflog = ARGV_ARRAY_INIT;
  44static struct argv_array repack = ARGV_ARRAY_INIT;
  45static struct argv_array prune = ARGV_ARRAY_INIT;
  46static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  47static struct argv_array rerere = ARGV_ARRAY_INIT;
  48
  49static struct tempfile pidfile;
  50static struct lock_file log_lock;
  51
  52static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
  53
  54static void clean_pack_garbage(void)
  55{
  56        int i;
  57        for (i = 0; i < pack_garbage.nr; i++)
  58                unlink_or_warn(pack_garbage.items[i].string);
  59        string_list_clear(&pack_garbage, 0);
  60}
  61
  62static void report_pack_garbage(unsigned seen_bits, const char *path)
  63{
  64        if (seen_bits == PACKDIR_FILE_IDX)
  65                string_list_append(&pack_garbage, path);
  66}
  67
  68static void process_log_file(void)
  69{
  70        struct stat st;
  71        if (fstat(get_lock_file_fd(&log_lock), &st)) {
  72                /*
  73                 * Perhaps there was an i/o error or another
  74                 * unlikely situation.  Try to make a note of
  75                 * this in gc.log along with any existing
  76                 * messages.
  77                 */
  78                int saved_errno = errno;
  79                fprintf(stderr, _("Failed to fstat %s: %s"),
  80                        get_tempfile_path(&log_lock.tempfile),
  81                        strerror(saved_errno));
  82                fflush(stderr);
  83                commit_lock_file(&log_lock);
  84                errno = saved_errno;
  85        } else if (st.st_size) {
  86                /* There was some error recorded in the lock file */
  87                commit_lock_file(&log_lock);
  88        } else {
  89                /* No error, clean up any old gc.log */
  90                unlink(git_path("gc.log"));
  91                rollback_lock_file(&log_lock);
  92        }
  93}
  94
  95static void process_log_file_at_exit(void)
  96{
  97        fflush(stderr);
  98        process_log_file();
  99}
 100
 101static void process_log_file_on_signal(int signo)
 102{
 103        process_log_file();
 104        sigchain_pop(signo);
 105        raise(signo);
 106}
 107
 108static void gc_config(void)
 109{
 110        const char *value;
 111
 112        if (!git_config_get_value("gc.packrefs", &value)) {
 113                if (value && !strcmp(value, "notbare"))
 114                        pack_refs = -1;
 115                else
 116                        pack_refs = git_config_bool("gc.packrefs", value);
 117        }
 118
 119        git_config_get_int("gc.aggressivewindow", &aggressive_window);
 120        git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 121        git_config_get_int("gc.auto", &gc_auto_threshold);
 122        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
 123        git_config_get_bool("gc.autodetach", &detach_auto);
 124        git_config_get_expiry("gc.pruneexpire", &prune_expire);
 125        git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
 126        git_config_get_expiry("gc.logexpiry", &gc_log_expire);
 127
 128        git_config(git_default_config, NULL);
 129}
 130
 131static int too_many_loose_objects(void)
 132{
 133        /*
 134         * Quickly check if a "gc" is needed, by estimating how
 135         * many loose objects there are.  Because SHA-1 is evenly
 136         * distributed, we can check only one and get a reasonable
 137         * estimate.
 138         */
 139        DIR *dir;
 140        struct dirent *ent;
 141        int auto_threshold;
 142        int num_loose = 0;
 143        int needed = 0;
 144
 145        if (gc_auto_threshold <= 0)
 146                return 0;
 147
 148        dir = opendir(git_path("objects/17"));
 149        if (!dir)
 150                return 0;
 151
 152        auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
 153        while ((ent = readdir(dir)) != NULL) {
 154                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 155                    ent->d_name[38] != '\0')
 156                        continue;
 157                if (++num_loose > auto_threshold) {
 158                        needed = 1;
 159                        break;
 160                }
 161        }
 162        closedir(dir);
 163        return needed;
 164}
 165
 166static int too_many_packs(void)
 167{
 168        struct packed_git *p;
 169        int cnt;
 170
 171        if (gc_auto_pack_limit <= 0)
 172                return 0;
 173
 174        prepare_packed_git();
 175        for (cnt = 0, p = packed_git; p; p = p->next) {
 176                if (!p->pack_local)
 177                        continue;
 178                if (p->pack_keep)
 179                        continue;
 180                /*
 181                 * Perhaps check the size of the pack and count only
 182                 * very small ones here?
 183                 */
 184                cnt++;
 185        }
 186        return gc_auto_pack_limit < cnt;
 187}
 188
 189static void add_repack_all_option(void)
 190{
 191        if (prune_expire && !strcmp(prune_expire, "now"))
 192                argv_array_push(&repack, "-a");
 193        else {
 194                argv_array_push(&repack, "-A");
 195                if (prune_expire)
 196                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 197        }
 198}
 199
 200static void add_repack_incremental_option(void)
 201{
 202       argv_array_push(&repack, "--no-write-bitmap-index");
 203}
 204
 205static int need_to_gc(void)
 206{
 207        /*
 208         * Setting gc.auto to 0 or negative can disable the
 209         * automatic gc.
 210         */
 211        if (gc_auto_threshold <= 0)
 212                return 0;
 213
 214        /*
 215         * If there are too many loose objects, but not too many
 216         * packs, we run "repack -d -l".  If there are too many packs,
 217         * we run "repack -A -d -l".  Otherwise we tell the caller
 218         * there is no need.
 219         */
 220        if (too_many_packs())
 221                add_repack_all_option();
 222        else if (too_many_loose_objects())
 223                add_repack_incremental_option();
 224        else
 225                return 0;
 226
 227        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 228                return 0;
 229        return 1;
 230}
 231
 232/* return NULL on success, else hostname running the gc */
 233static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 234{
 235        static struct lock_file lock;
 236        char my_host[HOST_NAME_MAX + 1];
 237        struct strbuf sb = STRBUF_INIT;
 238        struct stat st;
 239        uintmax_t pid;
 240        FILE *fp;
 241        int fd;
 242        char *pidfile_path;
 243
 244        if (is_tempfile_active(&pidfile))
 245                /* already locked */
 246                return NULL;
 247
 248        if (xgethostname(my_host, sizeof(my_host)))
 249                xsnprintf(my_host, sizeof(my_host), "unknown");
 250
 251        pidfile_path = git_pathdup("gc.pid");
 252        fd = hold_lock_file_for_update(&lock, pidfile_path,
 253                                       LOCK_DIE_ON_ERROR);
 254        if (!force) {
 255                static char locking_host[HOST_NAME_MAX + 1];
 256                static char *scan_fmt;
 257                int should_exit;
 258
 259                if (!scan_fmt)
 260                        scan_fmt = xstrfmt("%s %%%dc", "%"SCNuMAX, HOST_NAME_MAX);
 261                fp = fopen(pidfile_path, "r");
 262                memset(locking_host, 0, sizeof(locking_host));
 263                should_exit =
 264                        fp != NULL &&
 265                        !fstat(fileno(fp), &st) &&
 266                        /*
 267                         * 12 hour limit is very generous as gc should
 268                         * never take that long. On the other hand we
 269                         * don't really need a strict limit here,
 270                         * running gc --auto one day late is not a big
 271                         * problem. --force can be used in manual gc
 272                         * after the user verifies that no gc is
 273                         * running.
 274                         */
 275                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 276                        fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
 277                        /* be gentle to concurrent "gc" on remote hosts */
 278                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 279                if (fp != NULL)
 280                        fclose(fp);
 281                if (should_exit) {
 282                        if (fd >= 0)
 283                                rollback_lock_file(&lock);
 284                        *ret_pid = pid;
 285                        free(pidfile_path);
 286                        return locking_host;
 287                }
 288        }
 289
 290        strbuf_addf(&sb, "%"PRIuMAX" %s",
 291                    (uintmax_t) getpid(), my_host);
 292        write_in_full(fd, sb.buf, sb.len);
 293        strbuf_release(&sb);
 294        commit_lock_file(&lock);
 295        register_tempfile(&pidfile, pidfile_path);
 296        free(pidfile_path);
 297        return NULL;
 298}
 299
 300static int report_last_gc_error(void)
 301{
 302        struct strbuf sb = STRBUF_INIT;
 303        int ret = 0;
 304        struct stat st;
 305        char *gc_log_path = git_pathdup("gc.log");
 306
 307        if (stat(gc_log_path, &st)) {
 308                if (errno == ENOENT)
 309                        goto done;
 310
 311                ret = error_errno(_("Can't stat %s"), gc_log_path);
 312                goto done;
 313        }
 314
 315        if (st.st_mtime < gc_log_expire_time)
 316                goto done;
 317
 318        ret = strbuf_read_file(&sb, gc_log_path, 0);
 319        if (ret > 0)
 320                ret = error(_("The last gc run reported the following. "
 321                               "Please correct the root cause\n"
 322                               "and remove %s.\n"
 323                               "Automatic cleanup will not be performed "
 324                               "until the file is removed.\n\n"
 325                               "%s"),
 326                            gc_log_path, sb.buf);
 327        strbuf_release(&sb);
 328done:
 329        free(gc_log_path);
 330        return ret;
 331}
 332
 333static int gc_before_repack(void)
 334{
 335        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 336                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 337
 338        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 339                return error(FAILED_RUN, reflog.argv[0]);
 340
 341        pack_refs = 0;
 342        prune_reflogs = 0;
 343        return 0;
 344}
 345
 346int cmd_gc(int argc, const char **argv, const char *prefix)
 347{
 348        int aggressive = 0;
 349        int auto_gc = 0;
 350        int quiet = 0;
 351        int force = 0;
 352        const char *name;
 353        pid_t pid;
 354        int daemonized = 0;
 355
 356        struct option builtin_gc_options[] = {
 357                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 358                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 359                        N_("prune unreferenced objects"),
 360                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 361                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 362                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 363                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 364                OPT_END()
 365        };
 366
 367        if (argc == 2 && !strcmp(argv[1], "-h"))
 368                usage_with_options(builtin_gc_usage, builtin_gc_options);
 369
 370        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 371        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 372        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 373        argv_array_pushl(&prune, "prune", "--expire", NULL);
 374        argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 375        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 376
 377        /* default expiry time, overwritten in gc_config */
 378        gc_config();
 379        if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
 380                die(_("Failed to parse gc.logexpiry value %s"), gc_log_expire);
 381
 382        if (pack_refs < 0)
 383                pack_refs = !is_bare_repository();
 384
 385        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 386                             builtin_gc_usage, 0);
 387        if (argc > 0)
 388                usage_with_options(builtin_gc_usage, builtin_gc_options);
 389
 390        if (aggressive) {
 391                argv_array_push(&repack, "-f");
 392                if (aggressive_depth > 0)
 393                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 394                if (aggressive_window > 0)
 395                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 396        }
 397        if (quiet)
 398                argv_array_push(&repack, "-q");
 399
 400        if (auto_gc) {
 401                /*
 402                 * Auto-gc should be least intrusive as possible.
 403                 */
 404                if (!need_to_gc())
 405                        return 0;
 406                if (!quiet) {
 407                        if (detach_auto)
 408                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 409                        else
 410                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 411                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 412                }
 413                if (detach_auto) {
 414                        if (report_last_gc_error())
 415                                return -1;
 416
 417                        if (lock_repo_for_gc(force, &pid))
 418                                return 0;
 419                        if (gc_before_repack())
 420                                return -1;
 421                        delete_tempfile(&pidfile);
 422
 423                        /*
 424                         * failure to daemonize is ok, we'll continue
 425                         * in foreground
 426                         */
 427                        daemonized = !daemonize();
 428                }
 429        } else
 430                add_repack_all_option();
 431
 432        name = lock_repo_for_gc(force, &pid);
 433        if (name) {
 434                if (auto_gc)
 435                        return 0; /* be quiet on --auto */
 436                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 437                    name, (uintmax_t)pid);
 438        }
 439
 440        if (daemonized) {
 441                hold_lock_file_for_update(&log_lock,
 442                                          git_path("gc.log"),
 443                                          LOCK_DIE_ON_ERROR);
 444                dup2(get_lock_file_fd(&log_lock), 2);
 445                sigchain_push_common(process_log_file_on_signal);
 446                atexit(process_log_file_at_exit);
 447        }
 448
 449        if (gc_before_repack())
 450                return -1;
 451
 452        if (!repository_format_precious_objects) {
 453                if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 454                        return error(FAILED_RUN, repack.argv[0]);
 455
 456                if (prune_expire) {
 457                        argv_array_push(&prune, prune_expire);
 458                        if (quiet)
 459                                argv_array_push(&prune, "--no-progress");
 460                        if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 461                                return error(FAILED_RUN, prune.argv[0]);
 462                }
 463        }
 464
 465        if (prune_worktrees_expire) {
 466                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 467                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 468                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 469        }
 470
 471        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 472                return error(FAILED_RUN, rerere.argv[0]);
 473
 474        report_garbage = report_pack_garbage;
 475        reprepare_packed_git();
 476        if (pack_garbage.nr > 0)
 477                clean_pack_garbage();
 478
 479        if (auto_gc && too_many_loose_objects())
 480                warning(_("There are too many unreachable loose objects; "
 481                        "run 'git prune' to remove them."));
 482
 483        if (!daemonized)
 484                unlink(git_path("gc.log"));
 485
 486        return 0;
 487}