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