Andrew's git / gitweb.git / builtin/gc.c
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builtin / gc.con commit Merge branch 'mm/rebase-i-post-rewrite-exec' (a6be52e)
   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 "lockfile.h"
  15#include "parse-options.h"
  16#include "run-command.h"
  17#include "sigchain.h"
  18#include "argv-array.h"
  19#include "commit.h"
  20
  21#define FAILED_RUN "failed to run %s"
  22
  23static const char * const builtin_gc_usage[] = {
  24        N_("git gc [<options>]"),
  25        NULL
  26};
  27
  28static int pack_refs = 1;
  29static int prune_reflogs = 1;
  30static int aggressive_depth = 250;
  31static int aggressive_window = 250;
  32static int gc_auto_threshold = 6700;
  33static int gc_auto_pack_limit = 50;
  34static int detach_auto = 1;
  35static const char *prune_expire = "2.weeks.ago";
  36static const char *prune_worktrees_expire = "3.months.ago";
  37
  38static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  39static struct argv_array reflog = ARGV_ARRAY_INIT;
  40static struct argv_array repack = ARGV_ARRAY_INIT;
  41static struct argv_array prune = ARGV_ARRAY_INIT;
  42static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  43static struct argv_array rerere = ARGV_ARRAY_INIT;
  44
  45static char *pidfile;
  46
  47static void remove_pidfile(void)
  48{
  49        if (pidfile)
  50                unlink(pidfile);
  51}
  52
  53static void remove_pidfile_on_signal(int signo)
  54{
  55        remove_pidfile();
  56        sigchain_pop(signo);
  57        raise(signo);
  58}
  59
  60static void git_config_date_string(const char *key, const char **output)
  61{
  62        if (git_config_get_string_const(key, output))
  63                return;
  64        if (strcmp(*output, "now")) {
  65                unsigned long now = approxidate("now");
  66                if (approxidate(*output) >= now)
  67                        git_die_config(key, _("Invalid %s: '%s'"), key, *output);
  68        }
  69}
  70
  71static void gc_config(void)
  72{
  73        const char *value;
  74
  75        if (!git_config_get_value("gc.packrefs", &value)) {
  76                if (value && !strcmp(value, "notbare"))
  77                        pack_refs = -1;
  78                else
  79                        pack_refs = git_config_bool("gc.packrefs", value);
  80        }
  81
  82        git_config_get_int("gc.aggressivewindow", &aggressive_window);
  83        git_config_get_int("gc.aggressivedepth", &aggressive_depth);
  84        git_config_get_int("gc.auto", &gc_auto_threshold);
  85        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
  86        git_config_get_bool("gc.autodetach", &detach_auto);
  87        git_config_date_string("gc.pruneexpire", &prune_expire);
  88        git_config_date_string("gc.pruneworktreesexpire", &prune_worktrees_expire);
  89        git_config(git_default_config, NULL);
  90}
  91
  92static int too_many_loose_objects(void)
  93{
  94        /*
  95         * Quickly check if a "gc" is needed, by estimating how
  96         * many loose objects there are.  Because SHA-1 is evenly
  97         * distributed, we can check only one and get a reasonable
  98         * estimate.
  99         */
 100        char path[PATH_MAX];
 101        const char *objdir = get_object_directory();
 102        DIR *dir;
 103        struct dirent *ent;
 104        int auto_threshold;
 105        int num_loose = 0;
 106        int needed = 0;
 107
 108        if (gc_auto_threshold <= 0)
 109                return 0;
 110
 111        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 112                warning(_("insanely long object directory %.*s"), 50, objdir);
 113                return 0;
 114        }
 115        dir = opendir(path);
 116        if (!dir)
 117                return 0;
 118
 119        auto_threshold = (gc_auto_threshold + 255) / 256;
 120        while ((ent = readdir(dir)) != NULL) {
 121                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 122                    ent->d_name[38] != '\0')
 123                        continue;
 124                if (++num_loose > auto_threshold) {
 125                        needed = 1;
 126                        break;
 127                }
 128        }
 129        closedir(dir);
 130        return needed;
 131}
 132
 133static int too_many_packs(void)
 134{
 135        struct packed_git *p;
 136        int cnt;
 137
 138        if (gc_auto_pack_limit <= 0)
 139                return 0;
 140
 141        prepare_packed_git();
 142        for (cnt = 0, p = packed_git; p; p = p->next) {
 143                if (!p->pack_local)
 144                        continue;
 145                if (p->pack_keep)
 146                        continue;
 147                /*
 148                 * Perhaps check the size of the pack and count only
 149                 * very small ones here?
 150                 */
 151                cnt++;
 152        }
 153        return gc_auto_pack_limit <= cnt;
 154}
 155
 156static void add_repack_all_option(void)
 157{
 158        if (prune_expire && !strcmp(prune_expire, "now"))
 159                argv_array_push(&repack, "-a");
 160        else {
 161                argv_array_push(&repack, "-A");
 162                if (prune_expire)
 163                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 164        }
 165}
 166
 167static int need_to_gc(void)
 168{
 169        /*
 170         * Setting gc.auto to 0 or negative can disable the
 171         * automatic gc.
 172         */
 173        if (gc_auto_threshold <= 0)
 174                return 0;
 175
 176        /*
 177         * If there are too many loose objects, but not too many
 178         * packs, we run "repack -d -l".  If there are too many packs,
 179         * we run "repack -A -d -l".  Otherwise we tell the caller
 180         * there is no need.
 181         */
 182        if (too_many_packs())
 183                add_repack_all_option();
 184        else if (!too_many_loose_objects())
 185                return 0;
 186
 187        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 188                return 0;
 189        return 1;
 190}
 191
 192/* return NULL on success, else hostname running the gc */
 193static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 194{
 195        static struct lock_file lock;
 196        char my_host[128];
 197        struct strbuf sb = STRBUF_INIT;
 198        struct stat st;
 199        uintmax_t pid;
 200        FILE *fp;
 201        int fd;
 202
 203        if (pidfile)
 204                /* already locked */
 205                return NULL;
 206
 207        if (gethostname(my_host, sizeof(my_host)))
 208                strcpy(my_host, "unknown");
 209
 210        fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
 211                                       LOCK_DIE_ON_ERROR);
 212        if (!force) {
 213                static char locking_host[128];
 214                int should_exit;
 215                fp = fopen(git_path("gc.pid"), "r");
 216                memset(locking_host, 0, sizeof(locking_host));
 217                should_exit =
 218                        fp != NULL &&
 219                        !fstat(fileno(fp), &st) &&
 220                        /*
 221                         * 12 hour limit is very generous as gc should
 222                         * never take that long. On the other hand we
 223                         * don't really need a strict limit here,
 224                         * running gc --auto one day late is not a big
 225                         * problem. --force can be used in manual gc
 226                         * after the user verifies that no gc is
 227                         * running.
 228                         */
 229                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 230                        fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
 231                        /* be gentle to concurrent "gc" on remote hosts */
 232                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 233                if (fp != NULL)
 234                        fclose(fp);
 235                if (should_exit) {
 236                        if (fd >= 0)
 237                                rollback_lock_file(&lock);
 238                        *ret_pid = pid;
 239                        return locking_host;
 240                }
 241        }
 242
 243        strbuf_addf(&sb, "%"PRIuMAX" %s",
 244                    (uintmax_t) getpid(), my_host);
 245        write_in_full(fd, sb.buf, sb.len);
 246        strbuf_release(&sb);
 247        commit_lock_file(&lock);
 248
 249        pidfile = git_pathdup("gc.pid");
 250        sigchain_push_common(remove_pidfile_on_signal);
 251        atexit(remove_pidfile);
 252
 253        return NULL;
 254}
 255
 256static int gc_before_repack(void)
 257{
 258        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 259                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 260
 261        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 262                return error(FAILED_RUN, reflog.argv[0]);
 263
 264        pack_refs = 0;
 265        prune_reflogs = 0;
 266        return 0;
 267}
 268
 269int cmd_gc(int argc, const char **argv, const char *prefix)
 270{
 271        int aggressive = 0;
 272        int auto_gc = 0;
 273        int quiet = 0;
 274        int force = 0;
 275        const char *name;
 276        pid_t pid;
 277
 278        struct option builtin_gc_options[] = {
 279                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 280                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 281                        N_("prune unreferenced objects"),
 282                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 283                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 284                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 285                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 286                OPT_END()
 287        };
 288
 289        if (argc == 2 && !strcmp(argv[1], "-h"))
 290                usage_with_options(builtin_gc_usage, builtin_gc_options);
 291
 292        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 293        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 294        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 295        argv_array_pushl(&prune, "prune", "--expire", NULL);
 296        argv_array_pushl(&prune_worktrees, "prune", "--worktrees", "--expire", NULL);
 297        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 298
 299        gc_config();
 300
 301        if (pack_refs < 0)
 302                pack_refs = !is_bare_repository();
 303
 304        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 305                             builtin_gc_usage, 0);
 306        if (argc > 0)
 307                usage_with_options(builtin_gc_usage, builtin_gc_options);
 308
 309        if (aggressive) {
 310                argv_array_push(&repack, "-f");
 311                if (aggressive_depth > 0)
 312                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 313                if (aggressive_window > 0)
 314                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 315        }
 316        if (quiet)
 317                argv_array_push(&repack, "-q");
 318
 319        if (auto_gc) {
 320                /*
 321                 * Auto-gc should be least intrusive as possible.
 322                 */
 323                if (!need_to_gc())
 324                        return 0;
 325                if (!quiet) {
 326                        if (detach_auto)
 327                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 328                        else
 329                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 330                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 331                }
 332                if (detach_auto) {
 333                        if (gc_before_repack())
 334                                return -1;
 335                        /*
 336                         * failure to daemonize is ok, we'll continue
 337                         * in foreground
 338                         */
 339                        daemonize();
 340                }
 341        } else
 342                add_repack_all_option();
 343
 344        name = lock_repo_for_gc(force, &pid);
 345        if (name) {
 346                if (auto_gc)
 347                        return 0; /* be quiet on --auto */
 348                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 349                    name, (uintmax_t)pid);
 350        }
 351
 352        if (gc_before_repack())
 353                return -1;
 354
 355        if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 356                return error(FAILED_RUN, repack.argv[0]);
 357
 358        if (prune_expire) {
 359                argv_array_push(&prune, prune_expire);
 360                if (quiet)
 361                        argv_array_push(&prune, "--no-progress");
 362                if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 363                        return error(FAILED_RUN, prune.argv[0]);
 364        }
 365
 366        if (prune_worktrees_expire) {
 367                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 368                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 369                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 370        }
 371
 372        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 373                return error(FAILED_RUN, rerere.argv[0]);
 374
 375        if (auto_gc && too_many_loose_objects())
 376                warning(_("There are too many unreachable loose objects; "
 377                        "run 'git prune' to remove them."));
 378
 379        return 0;
 380}