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