3e67124eaaed256f440eea2a08101e87678eee0e
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#include "builtin.h"
14#include "repository.h"
15#include "config.h"
16#include "tempfile.h"
17#include "lockfile.h"
18#include "parse-options.h"
19#include "run-command.h"
20#include "sigchain.h"
21#include "argv-array.h"
22#include "commit.h"
23#include "packfile.h"
24#include "object-store.h"
25#define FAILED_RUN "failed to run %s"
27static const char * const builtin_gc_usage[] = {
29 N_("git gc [<options>]"),
30 NULL
31};
32static int pack_refs = 1;
34static int prune_reflogs = 1;
35static int aggressive_depth = 50;
36static int aggressive_window = 250;
37static int gc_auto_threshold = 6700;
38static int gc_auto_pack_limit = 50;
39static int detach_auto = 1;
40static timestamp_t gc_log_expire_time;
41static const char *gc_log_expire = "1.day.ago";
42static const char *prune_expire = "2.weeks.ago";
43static const char *prune_worktrees_expire = "3.months.ago";
44static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
46static struct argv_array reflog = ARGV_ARRAY_INIT;
47static struct argv_array repack = ARGV_ARRAY_INIT;
48static struct argv_array prune = ARGV_ARRAY_INIT;
49static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
50static struct argv_array rerere = ARGV_ARRAY_INIT;
51static struct tempfile *pidfile;
53static struct lock_file log_lock;
54static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
56static void clean_pack_garbage(void)
58{
59 int i;
60 for (i = 0; i < pack_garbage.nr; i++)
61 unlink_or_warn(pack_garbage.items[i].string);
62 string_list_clear(&pack_garbage, 0);
63}
64static void report_pack_garbage(unsigned seen_bits, const char *path)
66{
67 if (seen_bits == PACKDIR_FILE_IDX)
68 string_list_append(&pack_garbage, path);
69}
70static void process_log_file(void)
72{
73 struct stat st;
74 if (fstat(get_lock_file_fd(&log_lock), &st)) {
75 /*
76 * Perhaps there was an i/o error or another
77 * unlikely situation. Try to make a note of
78 * this in gc.log along with any existing
79 * messages.
80 */
81 int saved_errno = errno;
82 fprintf(stderr, _("Failed to fstat %s: %s"),
83 get_tempfile_path(log_lock.tempfile),
84 strerror(saved_errno));
85 fflush(stderr);
86 commit_lock_file(&log_lock);
87 errno = saved_errno;
88 } else if (st.st_size) {
89 /* There was some error recorded in the lock file */
90 commit_lock_file(&log_lock);
91 } else {
92 /* No error, clean up any old gc.log */
93 unlink(git_path("gc.log"));
94 rollback_lock_file(&log_lock);
95 }
96}
97static void process_log_file_at_exit(void)
99{
100 fflush(stderr);
101 process_log_file();
102}
103static void process_log_file_on_signal(int signo)
105{
106 process_log_file();
107 sigchain_pop(signo);
108 raise(signo);
109}
110static void gc_config(void)
112{
113 const char *value;
114 if (!git_config_get_value("gc.packrefs", &value)) {
116 if (value && !strcmp(value, "notbare"))
117 pack_refs = -1;
118 else
119 pack_refs = git_config_bool("gc.packrefs", value);
120 }
121 git_config_get_int("gc.aggressivewindow", &aggressive_window);
123 git_config_get_int("gc.aggressivedepth", &aggressive_depth);
124 git_config_get_int("gc.auto", &gc_auto_threshold);
125 git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
126 git_config_get_bool("gc.autodetach", &detach_auto);
127 git_config_get_expiry("gc.pruneexpire", &prune_expire);
128 git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
129 git_config_get_expiry("gc.logexpiry", &gc_log_expire);
130 git_config(git_default_config, NULL);
132}
133static int too_many_loose_objects(void)
135{
136 /*
137 * Quickly check if a "gc" is needed, by estimating how
138 * many loose objects there are. Because SHA-1 is evenly
139 * distributed, we can check only one and get a reasonable
140 * estimate.
141 */
142 DIR *dir;
143 struct dirent *ent;
144 int auto_threshold;
145 int num_loose = 0;
146 int needed = 0;
147 if (gc_auto_threshold <= 0)
149 return 0;
150 dir = opendir(git_path("objects/17"));
152 if (!dir)
153 return 0;
154 auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
156 while ((ent = readdir(dir)) != NULL) {
157 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
158 ent->d_name[38] != '\0')
159 continue;
160 if (++num_loose > auto_threshold) {
161 needed = 1;
162 break;
163 }
164 }
165 closedir(dir);
166 return needed;
167}
168static int too_many_packs(void)
170{
171 struct packed_git *p;
172 int cnt;
173 if (gc_auto_pack_limit <= 0)
175 return 0;
176 for (cnt = 0, p = get_packed_git(the_repository); p; p = p->next) {
178 if (!p->pack_local)
179 continue;
180 if (p->pack_keep)
181 continue;
182 /*
183 * Perhaps check the size of the pack and count only
184 * very small ones here?
185 */
186 cnt++;
187 }
188 return gc_auto_pack_limit < cnt;
189}
190static void add_repack_all_option(void)
192{
193 if (prune_expire && !strcmp(prune_expire, "now"))
194 argv_array_push(&repack, "-a");
195 else {
196 argv_array_push(&repack, "-A");
197 if (prune_expire)
198 argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
199 }
200}
201static void add_repack_incremental_option(void)
203{
204 argv_array_push(&repack, "--no-write-bitmap-index");
205}
206static int need_to_gc(void)
208{
209 /*
210 * Setting gc.auto to 0 or negative can disable the
211 * automatic gc.
212 */
213 if (gc_auto_threshold <= 0)
214 return 0;
215 /*
217 * If there are too many loose objects, but not too many
218 * packs, we run "repack -d -l". If there are too many packs,
219 * we run "repack -A -d -l". Otherwise we tell the caller
220 * there is no need.
221 */
222 if (too_many_packs())
223 add_repack_all_option();
224 else if (too_many_loose_objects())
225 add_repack_incremental_option();
226 else
227 return 0;
228 if (run_hook_le(NULL, "pre-auto-gc", NULL))
230 return 0;
231 return 1;
232}
233/* return NULL on success, else hostname running the gc */
235static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
236{
237 static struct lock_file lock;
238 char my_host[HOST_NAME_MAX + 1];
239 struct strbuf sb = STRBUF_INIT;
240 struct stat st;
241 uintmax_t pid;
242 FILE *fp;
243 int fd;
244 char *pidfile_path;
245 if (is_tempfile_active(pidfile))
247 /* already locked */
248 return NULL;
249 if (xgethostname(my_host, sizeof(my_host)))
251 xsnprintf(my_host, sizeof(my_host), "unknown");
252 pidfile_path = git_pathdup("gc.pid");
254 fd = hold_lock_file_for_update(&lock, pidfile_path,
255 LOCK_DIE_ON_ERROR);
256 if (!force) {
257 static char locking_host[HOST_NAME_MAX + 1];
258 static char *scan_fmt;
259 int should_exit;
260 if (!scan_fmt)
262 scan_fmt = xstrfmt("%s %%%ds", "%"SCNuMAX, HOST_NAME_MAX);
263 fp = fopen(pidfile_path, "r");
264 memset(locking_host, 0, sizeof(locking_host));
265 should_exit =
266 fp != NULL &&
267 !fstat(fileno(fp), &st) &&
268 /*
269 * 12 hour limit is very generous as gc should
270 * never take that long. On the other hand we
271 * don't really need a strict limit here,
272 * running gc --auto one day late is not a big
273 * problem. --force can be used in manual gc
274 * after the user verifies that no gc is
275 * running.
276 */
277 time(NULL) - st.st_mtime <= 12 * 3600 &&
278 fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
279 /* be gentle to concurrent "gc" on remote hosts */
280 (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
281 if (fp != NULL)
282 fclose(fp);
283 if (should_exit) {
284 if (fd >= 0)
285 rollback_lock_file(&lock);
286 *ret_pid = pid;
287 free(pidfile_path);
288 return locking_host;
289 }
290 }
291 strbuf_addf(&sb, "%"PRIuMAX" %s",
293 (uintmax_t) getpid(), my_host);
294 write_in_full(fd, sb.buf, sb.len);
295 strbuf_release(&sb);
296 commit_lock_file(&lock);
297 pidfile = register_tempfile(pidfile_path);
298 free(pidfile_path);
299 return NULL;
300}
301static int report_last_gc_error(void)
303{
304 struct strbuf sb = STRBUF_INIT;
305 int ret = 0;
306 struct stat st;
307 char *gc_log_path = git_pathdup("gc.log");
308 if (stat(gc_log_path, &st)) {
310 if (errno == ENOENT)
311 goto done;
312 ret = error_errno(_("Can't stat %s"), gc_log_path);
314 goto done;
315 }
316 if (st.st_mtime < gc_log_expire_time)
318 goto done;
319 ret = strbuf_read_file(&sb, gc_log_path, 0);
321 if (ret > 0)
322 ret = error(_("The last gc run reported the following. "
323 "Please correct the root cause\n"
324 "and remove %s.\n"
325 "Automatic cleanup will not be performed "
326 "until the file is removed.\n\n"
327 "%s"),
328 gc_log_path, sb.buf);
329 strbuf_release(&sb);
330done:
331 free(gc_log_path);
332 return ret;
333}
334static int gc_before_repack(void)
336{
337 if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
338 return error(FAILED_RUN, pack_refs_cmd.argv[0]);
339 if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
341 return error(FAILED_RUN, reflog.argv[0]);
342 pack_refs = 0;
344 prune_reflogs = 0;
345 return 0;
346}
347int cmd_gc(int argc, const char **argv, const char *prefix)
349{
350 int aggressive = 0;
351 int auto_gc = 0;
352 int quiet = 0;
353 int force = 0;
354 const char *name;
355 pid_t pid;
356 int daemonized = 0;
357 struct option builtin_gc_options[] = {
359 OPT__QUIET(&quiet, N_("suppress progress reporting")),
360 { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
361 N_("prune unreferenced objects"),
362 PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
363 OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
364 OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"),
365 PARSE_OPT_NOCOMPLETE),
366 OPT_BOOL_F(0, "force", &force,
367 N_("force running gc even if there may be another gc running"),
368 PARSE_OPT_NOCOMPLETE),
369 OPT_END()
370 };
371 if (argc == 2 && !strcmp(argv[1], "-h"))
373 usage_with_options(builtin_gc_usage, builtin_gc_options);
374 argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
376 argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
377 argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
378 argv_array_pushl(&prune, "prune", "--expire", NULL);
379 argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
380 argv_array_pushl(&rerere, "rerere", "gc", NULL);
381 /* default expiry time, overwritten in gc_config */
383 gc_config();
384 if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
385 die(_("Failed to parse gc.logexpiry value %s"), gc_log_expire);
386 if (pack_refs < 0)
388 pack_refs = !is_bare_repository();
389 argc = parse_options(argc, argv, prefix, builtin_gc_options,
391 builtin_gc_usage, 0);
392 if (argc > 0)
393 usage_with_options(builtin_gc_usage, builtin_gc_options);
394 if (aggressive) {
396 argv_array_push(&repack, "-f");
397 if (aggressive_depth > 0)
398 argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
399 if (aggressive_window > 0)
400 argv_array_pushf(&repack, "--window=%d", aggressive_window);
401 }
402 if (quiet)
403 argv_array_push(&repack, "-q");
404 if (auto_gc) {
406 /*
407 * Auto-gc should be least intrusive as possible.
408 */
409 if (!need_to_gc())
410 return 0;
411 if (!quiet) {
412 if (detach_auto)
413 fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
414 else
415 fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
416 fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
417 }
418 if (detach_auto) {
419 if (report_last_gc_error())
420 return -1;
421 if (lock_repo_for_gc(force, &pid))
423 return 0;
424 if (gc_before_repack())
425 return -1;
426 delete_tempfile(&pidfile);
427 /*
429 * failure to daemonize is ok, we'll continue
430 * in foreground
431 */
432 daemonized = !daemonize();
433 }
434 } else
435 add_repack_all_option();
436 name = lock_repo_for_gc(force, &pid);
438 if (name) {
439 if (auto_gc)
440 return 0; /* be quiet on --auto */
441 die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
442 name, (uintmax_t)pid);
443 }
444 if (daemonized) {
446 hold_lock_file_for_update(&log_lock,
447 git_path("gc.log"),
448 LOCK_DIE_ON_ERROR);
449 dup2(get_lock_file_fd(&log_lock), 2);
450 sigchain_push_common(process_log_file_on_signal);
451 atexit(process_log_file_at_exit);
452 }
453 if (gc_before_repack())
455 return -1;
456 if (!repository_format_precious_objects) {
458 if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
459 return error(FAILED_RUN, repack.argv[0]);
460 if (prune_expire) {
462 argv_array_push(&prune, prune_expire);
463 if (quiet)
464 argv_array_push(&prune, "--no-progress");
465 if (repository_format_partial_clone)
466 argv_array_push(&prune,
467 "--exclude-promisor-objects");
468 if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
469 return error(FAILED_RUN, prune.argv[0]);
470 }
471 }
472 if (prune_worktrees_expire) {
474 argv_array_push(&prune_worktrees, prune_worktrees_expire);
475 if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
476 return error(FAILED_RUN, prune_worktrees.argv[0]);
477 }
478 if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
480 return error(FAILED_RUN, rerere.argv[0]);
481 report_garbage = report_pack_garbage;
483 reprepare_packed_git(the_repository);
484 if (pack_garbage.nr > 0)
485 clean_pack_garbage();
486 if (auto_gc && too_many_loose_objects())
488 warning(_("There are too many unreachable loose objects; "
489 "run 'git prune' to remove them."));
490 if (!daemonized)
492 unlink(git_path("gc.log"));
493 return 0;
495}