[PATCH v3] gc: reject if another gc is running, unless --force is given
- From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
- Date
- Aug 5, 2013, 14:19 UTC
- Message-ID
- <1375712354-13171-1-git-send-email-pclouds@gmail.com>
- In-Reply-To
- <1375510890-4728-1-git-send-email-pclouds@gmail.com>
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-%s.pid.
uname() and kill(..,0) are added to MinGW compatibility layer so that it'll work on Windows. Actually uname() is stub so it won't prevent multiple gc running on a shared repo. But that's for Windows contributors to step in.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> --- - new code is taken out in a separate function for clarity - file locking - implementing kill(pid, 0) on windows (but not tested)
Documentation/git-gc.txt | 6 ++++- builtin/gc.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++ compat/mingw.c | 6 +++++ compat/mingw.h | 6 +++++ git-compat-util.h | 1 + 5 files changed, 80 insertions(+), 1 deletion(-)
diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt index 2402ed6..e158a3b 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=<date> | --no-prune] +'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] DESCRIPTION ----------- @@ -72,6 +72,10 @@ 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 6be6c8d..1f33908 100644 --- a/builtin/gc.c +++ b/builtin/gc.c @@ -167,11 +167,66 @@ static int need_to_gc(void) return 1; } +static int gc_running(int force) +{ + static struct lock_file lock; + struct utsname utsname; + struct stat st; + uintmax_t pid; + FILE *fp; + int fd, should_exit; + + if (uname(&utsname)) + strcpy(utsname.nodename, "unknown"); + + fd = hold_lock_file_for_update(&lock, + git_path("gc-%s.pid", utsname.nodename), 0); + if (!force) { + if (fd < 0) + return 1; + + fp = fopen(git_path("gc-%s.pid", utsname.nodename), "r"); + 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, &pid) == 1 && + !kill(pid, 0); + if (fp != NULL) + fclose(fp); + if (should_exit) { + if (fd >= 0) + rollback_lock_file(&lock); + return 1; + } + } + + if (fd >= 0) { + struct strbuf sb = STRBUF_INIT; + strbuf_addf(&sb, "%"PRIuMAX"\n", (uintmax_t) getpid()); + write_in_full(fd, sb.buf, sb.len); + strbuf_release(&sb); + commit_lock_file(&lock); + } + + return 0; +} + int cmd_gc(int argc, const char **argv, const char *prefix) { int aggressive = 0; int auto_gc = 0; int quiet = 0; + int force = 0; struct option builtin_gc_options[] = { OPT__QUIET(&quiet, N_("suppress progress reporting")), @@ -180,6 +235,7 @@ 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 +281,12 @@ int cmd_gc(int argc, const char **argv, const char *prefix) } else add_repack_all_option(); + if (gc_running(force)) { + if (auto_gc) + return 0; /* be quiet on --auto */ + die(_("gc is already running (use --force if not)")); + } + 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 bb92c43..22ee9ef 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; diff --git a/compat/mingw.h b/compat/mingw.h index bd0a88b..2c25d2d 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -68,6 +68,10 @@ struct itimerval { }; #define ITIMER_REAL 0 +struct utsname { + char nodename[128]; +}; + /* * sanitize preprocessor namespace polluted by Windows headers defining * macros which collide with git local versions @@ -86,6 +90,8 @@ static inline int fchmod(int fildes, mode_t mode) { errno = ENOSYS; return -1; } static inline pid_t fork(void) { errno = ENOSYS; return -1; } +static inline int uname(struct utsname *buf) +{ errno = ENOSYS; return -1; } static inline unsigned int alarm(unsigned int seconds) { return 0; } static inline int fsync(int fd) diff --git a/git-compat-util.h b/git-compat-util.h index 115cb1d..c6a53cb 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -139,6 +139,7 @@ #include <sys/resource.h> #include <sys/socket.h> #include <sys/ioctl.h> +#include <sys/utsname.h> #include <termios.h> #ifndef NO_SYS_SELECT_H #include <sys/select.h>
-- 1.8.2.83.gc99314b