Andrew's git / gitweb.git / builtin/gc.c
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builtin / gc.con commit name-rev: refactor logic to see if a new candidate is a better name (0041bf6)
   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 unsigned long gc_log_expire_time;
  37static const char *gc_log_expire = "1.day.ago";
  38static const char *prune_expire = "2.weeks.ago";
  39static const char *prune_worktrees_expire = "3.months.ago";
  40
  41static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  42static struct argv_array reflog = ARGV_ARRAY_INIT;
  43static struct argv_array repack = ARGV_ARRAY_INIT;
  44static struct argv_array prune = ARGV_ARRAY_INIT;
  45static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  46static struct argv_array rerere = ARGV_ARRAY_INIT;
  47
  48static struct tempfile pidfile;
  49static struct lock_file log_lock;
  50
  51static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
  52
  53static void clean_pack_garbage(void)
  54{
  55        int i;
  56        for (i = 0; i < pack_garbage.nr; i++)
  57                unlink_or_warn(pack_garbage.items[i].string);
  58        string_list_clear(&pack_garbage, 0);
  59}
  60
  61static void report_pack_garbage(unsigned seen_bits, const char *path)
  62{
  63        if (seen_bits == PACKDIR_FILE_IDX)
  64                string_list_append(&pack_garbage, path);
  65}
  66
  67static void process_log_file(void)
  68{
  69        struct stat st;
  70        if (fstat(get_lock_file_fd(&log_lock), &st)) {
  71                /*
  72                 * Perhaps there was an i/o error or another
  73                 * unlikely situation.  Try to make a note of
  74                 * this in gc.log along with any existing
  75                 * messages.
  76                 */
  77                int saved_errno = errno;
  78                fprintf(stderr, _("Failed to fstat %s: %s"),
  79                        get_tempfile_path(&log_lock.tempfile),
  80                        strerror(saved_errno));
  81                fflush(stderr);
  82                commit_lock_file(&log_lock);
  83                errno = saved_errno;
  84        } else if (st.st_size) {
  85                /* There was some error recorded in the lock file */
  86                commit_lock_file(&log_lock);
  87        } else {
  88                /* No error, clean up any old gc.log */
  89                unlink(git_path("gc.log"));
  90                rollback_lock_file(&log_lock);
  91        }
  92}
  93
  94static void process_log_file_at_exit(void)
  95{
  96        fflush(stderr);
  97        process_log_file();
  98}
  99
 100static void process_log_file_on_signal(int signo)
 101{
 102        process_log_file();
 103        sigchain_pop(signo);
 104        raise(signo);
 105}
 106
 107static void gc_config(void)
 108{
 109        const char *value;
 110
 111        if (!git_config_get_value("gc.packrefs", &value)) {
 112                if (value && !strcmp(value, "notbare"))
 113                        pack_refs = -1;
 114                else
 115                        pack_refs = git_config_bool("gc.packrefs", value);
 116        }
 117
 118        git_config_get_int("gc.aggressivewindow", &aggressive_window);
 119        git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 120        git_config_get_int("gc.auto", &gc_auto_threshold);
 121        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
 122        git_config_get_bool("gc.autodetach", &detach_auto);
 123        git_config_get_expiry("gc.pruneexpire", &prune_expire);
 124        git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
 125        git_config_get_expiry("gc.logexpiry", &gc_log_expire);
 126
 127        git_config(git_default_config, NULL);
 128}
 129
 130static int too_many_loose_objects(void)
 131{
 132        /*
 133         * Quickly check if a "gc" is needed, by estimating how
 134         * many loose objects there are.  Because SHA-1 is evenly
 135         * distributed, we can check only one and get a reasonable
 136         * estimate.
 137         */
 138        char path[PATH_MAX];
 139        const char *objdir = get_object_directory();
 140        DIR *dir;
 141        struct dirent *ent;
 142        int auto_threshold;
 143        int num_loose = 0;
 144        int needed = 0;
 145
 146        if (gc_auto_threshold <= 0)
 147                return 0;
 148
 149        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 150                warning(_("insanely long object directory %.*s"), 50, objdir);
 151                return 0;
 152        }
 153        dir = opendir(path);
 154        if (!dir)
 155                return 0;
 156
 157        auto_threshold = (gc_auto_threshold + 255) / 256;
 158        while ((ent = readdir(dir)) != NULL) {
 159                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 160                    ent->d_name[38] != '\0')
 161                        continue;
 162                if (++num_loose > auto_threshold) {
 163                        needed = 1;
 164                        break;
 165                }
 166        }
 167        closedir(dir);
 168        return needed;
 169}
 170
 171static int too_many_packs(void)
 172{
 173        struct packed_git *p;
 174        int cnt;
 175
 176        if (gc_auto_pack_limit <= 0)
 177                return 0;
 178
 179        prepare_packed_git();
 180        for (cnt = 0, p = packed_git; p; p = p->next) {
 181                if (!p->pack_local)
 182                        continue;
 183                if (p->pack_keep)
 184                        continue;
 185                /*
 186                 * Perhaps check the size of the pack and count only
 187                 * very small ones here?
 188                 */
 189                cnt++;
 190        }
 191        return gc_auto_pack_limit < cnt;
 192}
 193
 194static void add_repack_all_option(void)
 195{
 196        if (prune_expire && !strcmp(prune_expire, "now"))
 197                argv_array_push(&repack, "-a");
 198        else {
 199                argv_array_push(&repack, "-A");
 200                if (prune_expire)
 201                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 202        }
 203}
 204
 205static void add_repack_incremental_option(void)
 206{
 207       argv_array_push(&repack, "--no-write-bitmap-index");
 208}
 209
 210static int need_to_gc(void)
 211{
 212        /*
 213         * Setting gc.auto to 0 or negative can disable the
 214         * automatic gc.
 215         */
 216        if (gc_auto_threshold <= 0)
 217                return 0;
 218
 219        /*
 220         * If there are too many loose objects, but not too many
 221         * packs, we run "repack -d -l".  If there are too many packs,
 222         * we run "repack -A -d -l".  Otherwise we tell the caller
 223         * there is no need.
 224         */
 225        if (too_many_packs())
 226                add_repack_all_option();
 227        else if (too_many_loose_objects())
 228                add_repack_incremental_option();
 229        else
 230                return 0;
 231
 232        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 233                return 0;
 234        return 1;
 235}
 236
 237/* return NULL on success, else hostname running the gc */
 238static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 239{
 240        static struct lock_file lock;
 241        char my_host[128];
 242        struct strbuf sb = STRBUF_INIT;
 243        struct stat st;
 244        uintmax_t pid;
 245        FILE *fp;
 246        int fd;
 247        char *pidfile_path;
 248
 249        if (is_tempfile_active(&pidfile))
 250                /* already locked */
 251                return NULL;
 252
 253        if (gethostname(my_host, sizeof(my_host)))
 254                xsnprintf(my_host, sizeof(my_host), "unknown");
 255
 256        pidfile_path = git_pathdup("gc.pid");
 257        fd = hold_lock_file_for_update(&lock, pidfile_path,
 258                                       LOCK_DIE_ON_ERROR);
 259        if (!force) {
 260                static char locking_host[128];
 261                int should_exit;
 262                fp = fopen(pidfile_path, "r");
 263                memset(locking_host, 0, sizeof(locking_host));
 264                should_exit =
 265                        fp != NULL &&
 266                        !fstat(fileno(fp), &st) &&
 267                        /*
 268                         * 12 hour limit is very generous as gc should
 269                         * never take that long. On the other hand we
 270                         * don't really need a strict limit here,
 271                         * running gc --auto one day late is not a big
 272                         * problem. --force can be used in manual gc
 273                         * after the user verifies that no gc is
 274                         * running.
 275                         */
 276                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 277                        fscanf(fp, "%"SCNuMAX" %127c", &pid, locking_host) == 2 &&
 278                        /* be gentle to concurrent "gc" on remote hosts */
 279                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 280                if (fp != NULL)
 281                        fclose(fp);
 282                if (should_exit) {
 283                        if (fd >= 0)
 284                                rollback_lock_file(&lock);
 285                        *ret_pid = pid;
 286                        free(pidfile_path);
 287                        return locking_host;
 288                }
 289        }
 290
 291        strbuf_addf(&sb, "%"PRIuMAX" %s",
 292                    (uintmax_t) getpid(), my_host);
 293        write_in_full(fd, sb.buf, sb.len);
 294        strbuf_release(&sb);
 295        commit_lock_file(&lock);
 296        register_tempfile(&pidfile, pidfile_path);
 297        free(pidfile_path);
 298        return NULL;
 299}
 300
 301static int report_last_gc_error(void)
 302{
 303        struct strbuf sb = STRBUF_INIT;
 304        int ret = 0;
 305        struct stat st;
 306        char *gc_log_path = git_pathdup("gc.log");
 307
 308        if (stat(gc_log_path, &st)) {
 309                if (errno == ENOENT)
 310                        goto done;
 311
 312                ret = error_errno(_("Can't stat %s"), gc_log_path);
 313                goto done;
 314        }
 315
 316        if (st.st_mtime < gc_log_expire_time)
 317                goto done;
 318
 319        ret = strbuf_read_file(&sb, gc_log_path, 0);
 320        if (ret > 0)
 321                ret = error(_("The last gc run reported the following. "
 322                               "Please correct the root cause\n"
 323                               "and remove %s.\n"
 324                               "Automatic cleanup will not be performed "
 325                               "until the file is removed.\n\n"
 326                               "%s"),
 327                            gc_log_path, sb.buf);
 328        strbuf_release(&sb);
 329done:
 330        free(gc_log_path);
 331        return ret;
 332}
 333
 334static int gc_before_repack(void)
 335{
 336        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 337                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 338
 339        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 340                return error(FAILED_RUN, reflog.argv[0]);
 341
 342        pack_refs = 0;
 343        prune_reflogs = 0;
 344        return 0;
 345}
 346
 347int cmd_gc(int argc, const char **argv, const char *prefix)
 348{
 349        int aggressive = 0;
 350        int auto_gc = 0;
 351        int quiet = 0;
 352        int force = 0;
 353        const char *name;
 354        pid_t pid;
 355        int daemonized = 0;
 356
 357        struct option builtin_gc_options[] = {
 358                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 359                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 360                        N_("prune unreferenced objects"),
 361                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 362                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 363                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 364                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 365                OPT_END()
 366        };
 367
 368        if (argc == 2 && !strcmp(argv[1], "-h"))
 369                usage_with_options(builtin_gc_usage, builtin_gc_options);
 370
 371        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 372        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 373        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 374        argv_array_pushl(&prune, "prune", "--expire", NULL);
 375        argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 376        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 377
 378        /* default expiry time, overwritten in gc_config */
 379        gc_config();
 380        if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
 381                die(_("Failed to parse gc.logexpiry value %s"), gc_log_expire);
 382
 383        if (pack_refs < 0)
 384                pack_refs = !is_bare_repository();
 385
 386        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 387                             builtin_gc_usage, 0);
 388        if (argc > 0)
 389                usage_with_options(builtin_gc_usage, builtin_gc_options);
 390
 391        if (aggressive) {
 392                argv_array_push(&repack, "-f");
 393                if (aggressive_depth > 0)
 394                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 395                if (aggressive_window > 0)
 396                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 397        }
 398        if (quiet)
 399                argv_array_push(&repack, "-q");
 400
 401        if (auto_gc) {
 402                /*
 403                 * Auto-gc should be least intrusive as possible.
 404                 */
 405                if (!need_to_gc())
 406                        return 0;
 407                if (!quiet) {
 408                        if (detach_auto)
 409                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 410                        else
 411                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 412                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 413                }
 414                if (detach_auto) {
 415                        if (report_last_gc_error())
 416                                return -1;
 417
 418                        if (gc_before_repack())
 419                                return -1;
 420                        /*
 421                         * failure to daemonize is ok, we'll continue
 422                         * in foreground
 423                         */
 424                        daemonized = !daemonize();
 425                }
 426        } else
 427                add_repack_all_option();
 428
 429        name = lock_repo_for_gc(force, &pid);
 430        if (name) {
 431                if (auto_gc)
 432                        return 0; /* be quiet on --auto */
 433                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 434                    name, (uintmax_t)pid);
 435        }
 436
 437        if (daemonized) {
 438                hold_lock_file_for_update(&log_lock,
 439                                          git_path("gc.log"),
 440                                          LOCK_DIE_ON_ERROR);
 441                dup2(get_lock_file_fd(&log_lock), 2);
 442                sigchain_push_common(process_log_file_on_signal);
 443                atexit(process_log_file_at_exit);
 444        }
 445
 446        if (gc_before_repack())
 447                return -1;
 448
 449        if (!repository_format_precious_objects) {
 450                if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 451                        return error(FAILED_RUN, repack.argv[0]);
 452
 453                if (prune_expire) {
 454                        argv_array_push(&prune, prune_expire);
 455                        if (quiet)
 456                                argv_array_push(&prune, "--no-progress");
 457                        if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 458                                return error(FAILED_RUN, prune.argv[0]);
 459                }
 460        }
 461
 462        if (prune_worktrees_expire) {
 463                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 464                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 465                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 466        }
 467
 468        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 469                return error(FAILED_RUN, rerere.argv[0]);
 470
 471        report_garbage = report_pack_garbage;
 472        reprepare_packed_git();
 473        if (pack_garbage.nr > 0)
 474                clean_pack_garbage();
 475
 476        if (auto_gc && too_many_loose_objects())
 477                warning(_("There are too many unreachable loose objects; "
 478                        "run 'git prune' to remove them."));
 479
 480        if (!daemonized)
 481                unlink(git_path("gc.log"));
 482
 483        return 0;
 484}