diff options
Diffstat (limited to 'packfile.c')
| -rw-r--r-- | packfile.c | 44 |
1 files changed, 39 insertions, 5 deletions
@@ -1004,12 +1004,14 @@ void reprepare_packed_git(struct repository *r) { struct object_directory *odb; + obj_read_lock(); for (odb = r->objects->odb; odb; odb = odb->next) odb_clear_loose_cache(odb); r->objects->approximate_object_count_valid = 0; r->objects->packed_git_initialized = 0; prepare_packed_git(r); + obj_read_unlock(); } struct packed_git *get_packed_git(struct repository *r) @@ -1086,7 +1088,23 @@ unsigned long get_size_from_delta(struct packed_git *p, do { in = use_pack(p, w_curs, curpos, &stream.avail_in); stream.next_in = in; + /* + * Note: the window section returned by use_pack() must be + * available throughout git_inflate()'s unlocked execution. To + * ensure no other thread will modify the window in the + * meantime, we rely on the packed_window.inuse_cnt. This + * counter is incremented before window reading and checked + * before window disposal. + * + * Other worrying sections could be the call to close_pack_fd(), + * which can close packs even with in-use windows, and to + * reprepare_packed_git(). Regarding the former, mmap doc says: + * "closing the file descriptor does not unmap the region". And + * for the latter, it won't re-open already available packs. + */ + obj_read_unlock(); st = git_inflate(&stream, Z_FINISH); + obj_read_lock(); curpos += stream.next_in - in; } while ((st == Z_OK || st == Z_BUF_ERROR) && stream.total_out < sizeof(delta_head)); @@ -1162,11 +1180,11 @@ const struct packed_git *has_packed_and_bad(struct repository *r, return NULL; } -static off_t get_delta_base(struct packed_git *p, - struct pack_window **w_curs, - off_t *curpos, - enum object_type type, - off_t delta_obj_offset) +off_t get_delta_base(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + enum object_type type, + off_t delta_obj_offset) { unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL); off_t base_offset; @@ -1445,6 +1463,14 @@ static void add_delta_base_cache(struct packed_git *p, off_t base_offset, struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent)); struct list_head *lru, *tmp; + /* + * Check required to avoid redundant entries when more than one thread + * is unpacking the same object, in unpack_entry() (since its phases I + * and III might run concurrently across multiple threads). + */ + if (in_delta_base_cache(p, base_offset)) + return; + delta_base_cached += base_size; list_for_each_safe(lru, tmp, &delta_base_cache_lru) { @@ -1574,7 +1600,15 @@ static void *unpack_compressed_entry(struct packed_git *p, do { in = use_pack(p, w_curs, curpos, &stream.avail_in); stream.next_in = in; + /* + * Note: we must ensure the window section returned by + * use_pack() will be available throughout git_inflate()'s + * unlocked execution. Please refer to the comment at + * get_size_from_delta() to see how this is done. + */ + obj_read_unlock(); st = git_inflate(&stream, Z_FINISH); + obj_read_lock(); if (!stream.avail_out) break; /* the payload is larger than it should be */ curpos += stream.next_in - in; |