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_window = 250;
  30static int gc_auto_threshold = 6700;
  31static int gc_auto_pack_limit = 50;
  32static const char *prune_expire = "2.weeks.ago";
  33
  34static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  35static struct argv_array reflog = ARGV_ARRAY_INIT;
  36static struct argv_array repack = ARGV_ARRAY_INIT;
  37static struct argv_array prune = ARGV_ARRAY_INIT;
  38static struct argv_array rerere = ARGV_ARRAY_INIT;
  39
  40static char *pidfile;
  41
  42static void remove_pidfile(void)
  43{
  44        if (pidfile)
  45                unlink(pidfile);
  46}
  47
  48static void remove_pidfile_on_signal(int signo)
  49{
  50        remove_pidfile();
  51        sigchain_pop(signo);
  52        raise(signo);
  53}
  54
  55static int gc_config(const char *var, const char *value, void *cb)
  56{
  57        if (!strcmp(var, "gc.packrefs")) {
  58                if (value && !strcmp(value, "notbare"))
  59                        pack_refs = -1;
  60                else
  61                        pack_refs = git_config_bool(var, value);
  62                return 0;
  63        }
  64        if (!strcmp(var, "gc.aggressivewindow")) {
  65                aggressive_window = git_config_int(var, value);
  66                return 0;
  67        }
  68        if (!strcmp(var, "gc.auto")) {
  69                gc_auto_threshold = git_config_int(var, value);
  70                return 0;
  71        }
  72        if (!strcmp(var, "gc.autopacklimit")) {
  73                gc_auto_pack_limit = git_config_int(var, value);
  74                return 0;
  75        }
  76        if (!strcmp(var, "gc.pruneexpire")) {
  77                if (value && strcmp(value, "now")) {
  78                        unsigned long now = approxidate("now");
  79                        if (approxidate(value) >= now)
  80                                return error(_("Invalid %s: '%s'"), var, value);
  81                }
  82                return git_config_string(&prune_expire, var, value);
  83        }
  84        return git_default_config(var, value, cb);
  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(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        static char locking_host[128];
 192        char my_host[128];
 193        struct strbuf sb = STRBUF_INIT;
 194        struct stat st;
 195        uintmax_t pid;
 196        FILE *fp;
 197        int fd, should_exit;
 198
 199        if (pidfile)
 200                /* already locked */
 201                return NULL;
 202
 203        if (gethostname(my_host, sizeof(my_host)))
 204                strcpy(my_host, "unknown");
 205
 206        fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
 207                                       LOCK_DIE_ON_ERROR);
 208        if (!force) {
 209                fp = fopen(git_path("gc.pid"), "r");
 210                memset(locking_host, 0, sizeof(locking_host));
 211                should_exit =
 212                        fp != NULL &&
 213                        !fstat(fileno(fp), &st) &&
 214                        /*
 215                         * 12 hour limit is very generous as gc should
 216                         * never take that long. On the other hand we
 217                         * don't really need a strict limit here,
 218                         * running gc --auto one day late is not a big
 219                         * problem. --force can be used in manual gc
 220                         * after the user verifies that no gc is
 221                         * running.
 222                         */
 223                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 224                        fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
 225                        /* be gentle to concurrent "gc" on remote hosts */
 226                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 227                if (fp != NULL)
 228                        fclose(fp);
 229                if (should_exit) {
 230                        if (fd >= 0)
 231                                rollback_lock_file(&lock);
 232                        *ret_pid = pid;
 233                        return locking_host;
 234                }
 235        }
 236
 237        strbuf_addf(&sb, "%"PRIuMAX" %s",
 238                    (uintmax_t) getpid(), my_host);
 239        write_in_full(fd, sb.buf, sb.len);
 240        strbuf_release(&sb);
 241        commit_lock_file(&lock);
 242
 243        pidfile = git_pathdup("gc.pid");
 244        sigchain_push_common(remove_pidfile_on_signal);
 245        atexit(remove_pidfile);
 246
 247        return NULL;
 248}
 249
 250int cmd_gc(int argc, const char **argv, const char *prefix)
 251{
 252        int aggressive = 0;
 253        int auto_gc = 0;
 254        int quiet = 0;
 255        int force = 0;
 256        const char *name;
 257        pid_t pid;
 258
 259        struct option builtin_gc_options[] = {
 260                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 261                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 262                        N_("prune unreferenced objects"),
 263                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 264                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 265                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 266                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 267                OPT_END()
 268        };
 269
 270        if (argc == 2 && !strcmp(argv[1], "-h"))
 271                usage_with_options(builtin_gc_usage, builtin_gc_options);
 272
 273        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 274        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 275        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 276        argv_array_pushl(&prune, "prune", "--expire", NULL );
 277        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 278
 279        git_config(gc_config, NULL);
 280
 281        if (pack_refs < 0)
 282                pack_refs = !is_bare_repository();
 283
 284        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 285                             builtin_gc_usage, 0);
 286        if (argc > 0)
 287                usage_with_options(builtin_gc_usage, builtin_gc_options);
 288
 289        if (aggressive) {
 290                argv_array_push(&repack, "-f");
 291                argv_array_push(&repack, "--depth=250");
 292                if (aggressive_window > 0)
 293                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 294        }
 295        if (quiet)
 296                argv_array_push(&repack, "-q");
 297
 298        if (auto_gc) {
 299                /*
 300                 * Auto-gc should be least intrusive as possible.
 301                 */
 302                if (!need_to_gc())
 303                        return 0;
 304                if (!quiet)
 305                        fprintf(stderr,
 306                                        _("Auto packing the repository for optimum performance. You may also\n"
 307                                        "run \"git gc\" manually. See "
 308                                        "\"git help gc\" for more information.\n"));
 309        } else
 310                add_repack_all_option();
 311
 312        name = lock_repo_for_gc(force, &pid);
 313        if (name) {
 314                if (auto_gc)
 315                        return 0; /* be quiet on --auto */
 316                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 317                    name, (uintmax_t)pid);
 318        }
 319
 320        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 321                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 322
 323        if (run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 324                return error(FAILED_RUN, reflog.argv[0]);
 325
 326        if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 327                return error(FAILED_RUN, repack.argv[0]);
 328
 329        if (prune_expire) {
 330                argv_array_push(&prune, prune_expire);
 331                if (quiet)
 332                        argv_array_push(&prune, "--no-progress");
 333                if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 334                        return error(FAILED_RUN, prune.argv[0]);
 335        }
 336
 337        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 338                return error(FAILED_RUN, rerere.argv[0]);
 339
 340        if (auto_gc && too_many_loose_objects())
 341                warning(_("There are too many unreachable loose objects; "
 342                        "run 'git prune' to remove them."));
 343
 344        return 0;
 345}