index-pack: protect deepest_delta in multithread code

deepest_delta is a global variable but is updated without protection
in resolve_delta(), a multithreaded function. Add a new mutex for it,
but only protect and update when it's actually used (i.e. show_stat is
non-zero).

Another variable that will not be updated is delta_depth in "struct
object_entry" as it's only useful when show_stat is 1. Putting it in
"if (show_stat)" makes it clearer.

The local variable "stat" is renamed to "show_stat" after moving to
global scope because the name "stat" conflicts with stat(2) syscall.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 953dd3004e285ce7aa0432f4fe0eacb0d0c2c887..8fe9df5eba1322a0fc45883d2cf66bd8ca1614bb 100644 (file)
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -78,6 +78,7 @@ static int nr_threads;
 static int from_stdin;
 static int strict;
 static int verbose;
 static int from_stdin;
 static int strict;
 static int verbose;

+static int show_stat;

 
 static struct progress *progress;
 
 
 static struct progress *progress;
 


@@ -108,6 +109,10 @@ static pthread_mutex_t work_mutex;
 #define work_lock()            lock_mutex(&work_mutex)
 #define work_unlock()          unlock_mutex(&work_mutex)
 
 #define work_lock()            lock_mutex(&work_mutex)
 #define work_unlock()          unlock_mutex(&work_mutex)
 

+static pthread_mutex_t deepest_delta_mutex;
+#define deepest_delta_lock()   lock_mutex(&deepest_delta_mutex)
+#define deepest_delta_unlock() unlock_mutex(&deepest_delta_mutex)
+

 static pthread_key_t key;
 
 static inline void lock_mutex(pthread_mutex_t *mutex)
 static pthread_key_t key;
 
 static inline void lock_mutex(pthread_mutex_t *mutex)


@@ -130,6 +135,8 @@ static void init_thread(void)
        init_recursive_mutex(&read_mutex);
        pthread_mutex_init(&counter_mutex, NULL);
        pthread_mutex_init(&work_mutex, NULL);
        init_recursive_mutex(&read_mutex);
        pthread_mutex_init(&counter_mutex, NULL);
        pthread_mutex_init(&work_mutex, NULL);

+       if (show_stat)
+               pthread_mutex_init(&deepest_delta_mutex, NULL);

        pthread_key_create(&key, NULL);
        thread_data = xcalloc(nr_threads, sizeof(*thread_data));
        threads_active = 1;
        pthread_key_create(&key, NULL);
        thread_data = xcalloc(nr_threads, sizeof(*thread_data));
        threads_active = 1;


@@ -143,6 +150,8 @@ static void cleanup_thread(void)
        pthread_mutex_destroy(&read_mutex);
        pthread_mutex_destroy(&counter_mutex);
        pthread_mutex_destroy(&work_mutex);
        pthread_mutex_destroy(&read_mutex);
        pthread_mutex_destroy(&counter_mutex);
        pthread_mutex_destroy(&work_mutex);

+       if (show_stat)
+               pthread_mutex_destroy(&deepest_delta_mutex);

        pthread_key_delete(key);
        free(thread_data);
 }
        pthread_key_delete(key);
        free(thread_data);
 }


@@ -158,6 +167,9 @@ static void cleanup_thread(void)
 #define work_lock()
 #define work_unlock()
 
 #define work_lock()
 #define work_unlock()
 

+#define deepest_delta_lock()
+#define deepest_delta_unlock()
+

 #endif
 
 
 #endif
 
 


@@ -833,9 +845,13 @@ static void resolve_delta(struct object_entry *delta_obj,
        void *base_data, *delta_data;
 
        delta_obj->real_type = base->obj->real_type;
        void *base_data, *delta_data;
 
        delta_obj->real_type = base->obj->real_type;

-       delta_obj->delta_depth = base->obj->delta_depth + 1;
-       if (deepest_delta < delta_obj->delta_depth)
-               deepest_delta = delta_obj->delta_depth;
+       if (show_stat) {
+               delta_obj->delta_depth = base->obj->delta_depth + 1;
+               deepest_delta_lock();
+               if (deepest_delta < delta_obj->delta_depth)
+                       deepest_delta = delta_obj->delta_depth;
+               deepest_delta_unlock();
+       }

        delta_obj->base_object_no = base->obj - objects;
        delta_data = get_data_from_pack(delta_obj);
        base_data = get_base_data(base);
        delta_obj->base_object_no = base->obj - objects;
        delta_data = get_data_from_pack(delta_obj);
        base_data = get_base_data(base);


@@ -1461,7 +1477,7 @@ static void show_pack_info(int stat_only)
 
 int cmd_index_pack(int argc, const char **argv, const char *prefix)
 {
 
 int cmd_index_pack(int argc, const char **argv, const char *prefix)
 {

-       int i, fix_thin_pack = 0, verify = 0, stat_only = 0, stat = 0;
+       int i, fix_thin_pack = 0, verify = 0, stat_only = 0;

        const char *curr_pack, *curr_index;
        const char *index_name = NULL, *pack_name = NULL;
        const char *keep_name = NULL, *keep_msg = NULL;
        const char *curr_pack, *curr_index;
        const char *index_name = NULL, *pack_name = NULL;
        const char *keep_name = NULL, *keep_msg = NULL;


@@ -1494,10 +1510,10 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
                                verify = 1;
                        } else if (!strcmp(arg, "--verify-stat")) {
                                verify = 1;
                                verify = 1;
                        } else if (!strcmp(arg, "--verify-stat")) {
                                verify = 1;

-                               stat = 1;
+                               show_stat = 1;

                        } else if (!strcmp(arg, "--verify-stat-only")) {
                                verify = 1;
                        } else if (!strcmp(arg, "--verify-stat-only")) {
                                verify = 1;

-                               stat = 1;
+                               show_stat = 1;

                                stat_only = 1;
                        } else if (!strcmp(arg, "--keep")) {
                                keep_msg = "";
                                stat_only = 1;
                        } else if (!strcmp(arg, "--keep")) {
                                keep_msg = "";


@@ -1605,7 +1621,7 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
        if (strict)
                check_objects();
 
        if (strict)
                check_objects();
 

-       if (stat)
+       if (show_stat)

                show_pack_info(stat_only);
 
        idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
                show_pack_info(stat_only);
 
        idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));