From 64a99eb4760de2ce2f0c04e146c0a55c34f50f20 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Nguy=E1=BB=85n=20Th=C3=A1i=20Ng=E1=BB=8Dc=20Duy?= Date: Thu, 8 Aug 2013 18:05:38 +0700 Subject: [PATCH] gc: reject if another gc is running, unless --force is given MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This may happen when `git gc --auto` is run automatically, then the user, to avoid wait time, switches to a new terminal, keeps working and `git gc --auto` is started again because the first gc instance has not clean up the repository. This patch tries to avoid multiple gc running, especially in --auto mode. In the worst case, gc may be delayed 12 hours if a daemon reuses the pid stored in gc.pid. kill(pid, 0) support is added to MinGW port so it should work on Windows too. Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano --- Documentation/git-gc.txt | 6 +++- builtin/gc.c | 67 ++++++++++++++++++++++++++++++++++++++++ compat/mingw.c | 6 ++++ 3 files changed, 78 insertions(+), 1 deletion(-) diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt index b370b025b8..5d04ab0330 100644 --- a/Documentation/git-gc.txt +++ b/Documentation/git-gc.txt @@ -9,7 +9,7 @@ git-gc - Cleanup unnecessary files and optimize the local repository SYNOPSIS -------- [verse] -'git gc' [--aggressive] [--auto] [--quiet] [--prune= | --no-prune] +'git gc' [--aggressive] [--auto] [--quiet] [--prune= | --no-prune] [--force] DESCRIPTION ----------- @@ -71,6 +71,10 @@ automatic consolidation of packs. --quiet:: Suppress all progress reports. +--force:: + Force `git gc` to run even if there may be another `git gc` + instance running on this repository. + Configuration ------------- diff --git a/builtin/gc.c b/builtin/gc.c index 6be6c8d65b..6e0d81ab32 100644 --- a/builtin/gc.c +++ b/builtin/gc.c @@ -167,11 +167,69 @@ static int need_to_gc(void) return 1; } +/* return NULL on success, else hostname running the gc */ +static const char *lock_repo_for_gc(int force, pid_t* ret_pid) +{ + static struct lock_file lock; + static char locking_host[128]; + char my_host[128]; + struct strbuf sb = STRBUF_INIT; + struct stat st; + uintmax_t pid; + FILE *fp; + int fd, should_exit; + + if (gethostname(my_host, sizeof(my_host))) + strcpy(my_host, "unknown"); + + fd = hold_lock_file_for_update(&lock, git_path("gc.pid"), + LOCK_DIE_ON_ERROR); + if (!force) { + fp = fopen(git_path("gc.pid"), "r"); + memset(locking_host, 0, sizeof(locking_host)); + should_exit = + fp != NULL && + !fstat(fileno(fp), &st) && + /* + * 12 hour limit is very generous as gc should + * never take that long. On the other hand we + * don't really need a strict limit here, + * running gc --auto one day late is not a big + * problem. --force can be used in manual gc + * after the user verifies that no gc is + * running. + */ + time(NULL) - st.st_mtime <= 12 * 3600 && + fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 && + /* be gentle to concurrent "gc" on remote hosts */ + (strcmp(locking_host, my_host) || !kill(pid, 0)); + if (fp != NULL) + fclose(fp); + if (should_exit) { + if (fd >= 0) + rollback_lock_file(&lock); + *ret_pid = pid; + return locking_host; + } + } + + strbuf_addf(&sb, "%"PRIuMAX" %s", + (uintmax_t) getpid(), my_host); + write_in_full(fd, sb.buf, sb.len); + strbuf_release(&sb); + commit_lock_file(&lock); + + return NULL; +} + int cmd_gc(int argc, const char **argv, const char *prefix) { int aggressive = 0; int auto_gc = 0; int quiet = 0; + int force = 0; + const char *name; + pid_t pid; struct option builtin_gc_options[] = { OPT__QUIET(&quiet, N_("suppress progress reporting")), @@ -180,6 +238,7 @@ int cmd_gc(int argc, const char **argv, const char *prefix) PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire }, OPT_BOOLEAN(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")), OPT_BOOLEAN(0, "auto", &auto_gc, N_("enable auto-gc mode")), + OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")), OPT_END() }; @@ -225,6 +284,14 @@ int cmd_gc(int argc, const char **argv, const char *prefix) } else add_repack_all_option(); + name = lock_repo_for_gc(force, &pid); + if (name) { + if (auto_gc) + return 0; /* be quiet on --auto */ + die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"), + name, (uintmax_t)pid); + } + if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD)) return error(FAILED_RUN, pack_refs_cmd.argv[0]); diff --git a/compat/mingw.c b/compat/mingw.c index b673625580..2951389c69 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -1086,6 +1086,12 @@ int mingw_kill(pid_t pid, int sig) errno = err_win_to_posix(GetLastError()); CloseHandle(h); return -1; + } else if (pid > 0 && sig == 0) { + HANDLE h = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid); + if (h) { + CloseHandle(h); + return 0; + } } errno = EINVAL; -- 2.47.1