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_window = 250;
  31static int gc_auto_threshold = 6700;
  32static int gc_auto_pack_limit = 50;
  33static int detach_auto = 1;
  34static const char *prune_expire = "2.weeks.ago";
  35
  36static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  37static struct argv_array reflog = ARGV_ARRAY_INIT;
  38static struct argv_array repack = ARGV_ARRAY_INIT;
  39static struct argv_array prune = ARGV_ARRAY_INIT;
  40static struct argv_array rerere = ARGV_ARRAY_INIT;
  41
  42static char *pidfile;
  43
  44static void remove_pidfile(void)
  45{
  46        if (pidfile)
  47                unlink(pidfile);
  48}
  49
  50static void remove_pidfile_on_signal(int signo)
  51{
  52        remove_pidfile();
  53        sigchain_pop(signo);
  54        raise(signo);
  55}
  56
  57static int gc_config(const char *var, const char *value, void *cb)
  58{
  59        if (!strcmp(var, "gc.packrefs")) {
  60                if (value && !strcmp(value, "notbare"))
  61                        pack_refs = -1;
  62                else
  63                        pack_refs = git_config_bool(var, value);
  64                return 0;
  65        }
  66        if (!strcmp(var, "gc.aggressivewindow")) {
  67                aggressive_window = git_config_int(var, value);
  68                return 0;
  69        }
  70        if (!strcmp(var, "gc.auto")) {
  71                gc_auto_threshold = git_config_int(var, value);
  72                return 0;
  73        }
  74        if (!strcmp(var, "gc.autopacklimit")) {
  75                gc_auto_pack_limit = git_config_int(var, value);
  76                return 0;
  77        }
  78        if (!strcmp(var, "gc.autodetach")) {
  79                detach_auto = git_config_bool(var, value);
  80                return 0;
  81        }
  82        if (!strcmp(var, "gc.pruneexpire")) {
  83                if (value && strcmp(value, "now")) {
  84                        unsigned long now = approxidate("now");
  85                        if (approxidate(value) >= now)
  86                                return error(_("Invalid %s: '%s'"), var, value);
  87                }
  88                return git_config_string(&prune_expire, var, value);
  89        }
  90        return git_default_config(var, value, cb);
  91}
  92
  93static int too_many_loose_objects(void)
  94{
  95        /*
  96         * Quickly check if a "gc" is needed, by estimating how
  97         * many loose objects there are.  Because SHA-1 is evenly
  98         * distributed, we can check only one and get a reasonable
  99         * estimate.
 100         */
 101        char path[PATH_MAX];
 102        const char *objdir = get_object_directory();
 103        DIR *dir;
 104        struct dirent *ent;
 105        int auto_threshold;
 106        int num_loose = 0;
 107        int needed = 0;
 108
 109        if (gc_auto_threshold <= 0)
 110                return 0;
 111
 112        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 113                warning(_("insanely long object directory %.*s"), 50, objdir);
 114                return 0;
 115        }
 116        dir = opendir(path);
 117        if (!dir)
 118                return 0;
 119
 120        auto_threshold = (gc_auto_threshold + 255) / 256;
 121        while ((ent = readdir(dir)) != NULL) {
 122                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 123                    ent->d_name[38] != '\0')
 124                        continue;
 125                if (++num_loose > auto_threshold) {
 126                        needed = 1;
 127                        break;
 128                }
 129        }
 130        closedir(dir);
 131        return needed;
 132}
 133
 134static int too_many_packs(void)
 135{
 136        struct packed_git *p;
 137        int cnt;
 138
 139        if (gc_auto_pack_limit <= 0)
 140                return 0;
 141
 142        prepare_packed_git();
 143        for (cnt = 0, p = packed_git; p; p = p->next) {
 144                if (!p->pack_local)
 145                        continue;
 146                if (p->pack_keep)
 147                        continue;
 148                /*
 149                 * Perhaps check the size of the pack and count only
 150                 * very small ones here?
 151                 */
 152                cnt++;
 153        }
 154        return gc_auto_pack_limit <= cnt;
 155}
 156
 157static void add_repack_all_option(void)
 158{
 159        if (prune_expire && !strcmp(prune_expire, "now"))
 160                argv_array_push(&repack, "-a");
 161        else {
 162                argv_array_push(&repack, "-A");
 163                if (prune_expire)
 164                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 165        }
 166}
 167
 168static int need_to_gc(void)
 169{
 170        /*
 171         * Setting gc.auto to 0 or negative can disable the
 172         * automatic gc.
 173         */
 174        if (gc_auto_threshold <= 0)
 175                return 0;
 176
 177        /*
 178         * If there are too many loose objects, but not too many
 179         * packs, we run "repack -d -l".  If there are too many packs,
 180         * we run "repack -A -d -l".  Otherwise we tell the caller
 181         * there is no need.
 182         */
 183        if (too_many_packs())
 184                add_repack_all_option();
 185        else if (!too_many_loose_objects())
 186                return 0;
 187
 188        if (run_hook(NULL, "pre-auto-gc", NULL))
 189                return 0;
 190        return 1;
 191}
 192
 193/* return NULL on success, else hostname running the gc */
 194static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 195{
 196        static struct lock_file lock;
 197        static char locking_host[128];
 198        char my_host[128];
 199        struct strbuf sb = STRBUF_INIT;
 200        struct stat st;
 201        uintmax_t pid;
 202        FILE *fp;
 203        int fd, should_exit;
 204
 205        if (pidfile)
 206                /* already locked */
 207                return NULL;
 208
 209        if (gethostname(my_host, sizeof(my_host)))
 210                strcpy(my_host, "unknown");
 211
 212        fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
 213                                       LOCK_DIE_ON_ERROR);
 214        if (!force) {
 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(&rerere, "rerere", "gc", NULL);
 297
 298        git_config(gc_config, NULL);
 299
 300        if (pack_refs < 0)
 301                pack_refs = !is_bare_repository();
 302
 303        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 304                             builtin_gc_usage, 0);
 305        if (argc > 0)
 306                usage_with_options(builtin_gc_usage, builtin_gc_options);
 307
 308        if (aggressive) {
 309                argv_array_push(&repack, "-f");
 310                argv_array_push(&repack, "--depth=250");
 311                if (aggressive_window > 0)
 312                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 313        }
 314        if (quiet)
 315                argv_array_push(&repack, "-q");
 316
 317        if (auto_gc) {
 318                /*
 319                 * Auto-gc should be least intrusive as possible.
 320                 */
 321                if (!need_to_gc())
 322                        return 0;
 323                if (!quiet) {
 324                        if (detach_auto)
 325                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 326                        else
 327                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 328                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 329                }
 330                if (detach_auto) {
 331                        if (gc_before_repack())
 332                                return -1;
 333                        /*
 334                         * failure to daemonize is ok, we'll continue
 335                         * in foreground
 336                         */
 337                        daemonize();
 338                }
 339        } else
 340                add_repack_all_option();
 341
 342        name = lock_repo_for_gc(force, &pid);
 343        if (name) {
 344                if (auto_gc)
 345                        return 0; /* be quiet on --auto */
 346                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 347                    name, (uintmax_t)pid);
 348        }
 349
 350        if (gc_before_repack())
 351                return -1;
 352
 353        if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 354                return error(FAILED_RUN, repack.argv[0]);
 355
 356        if (prune_expire) {
 357                argv_array_push(&prune, prune_expire);
 358                if (quiet)
 359                        argv_array_push(&prune, "--no-progress");
 360                if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 361                        return error(FAILED_RUN, prune.argv[0]);
 362        }
 363
 364        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 365                return error(FAILED_RUN, rerere.argv[0]);
 366
 367        if (auto_gc && too_many_loose_objects())
 368                warning(_("There are too many unreachable loose objects; "
 369                        "run 'git prune' to remove them."));
 370
 371        return 0;
 372}