builtin/fsck.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "commit.h"
   4 #include "tree.h"
   5 #include "blob.h"
   6 #include "tag.h"
   7 #include "refs.h"
   8 #include "pack.h"
   9 #include "cache-tree.h"
  10 #include "tree-walk.h"
  11 #include "fsck.h"
  12 #include "parse-options.h"
  13 #include "dir.h"
  14 #include "progress.h"
  15
  16 #define REACHABLE 0x0001
  17 #define SEEN      0x0002
  18
  19 static int show_root;
  20 static int show_tags;
  21 static int show_unreachable;
  22 static int include_reflogs = 1;
  23 static int check_full = 1;
  24 static int check_strict;
  25 static int keep_cache_objects;
  26 static unsigned char head_sha1[20];
  27 static const char *head_points_at;
  28 static int errors_found;
  29 static int write_lost_and_found;
  30 static int verbose;
  31 static int show_progress = -1;
  32 static int show_dangling = 1;
  33 #define ERROR_OBJECT 01
  34 #define ERROR_REACHABLE 02
  35 #define ERROR_PACK 04
  36
  37 #ifdef NO_D_INO_IN_DIRENT
  38 #define SORT_DIRENT 0
  39 #define DIRENT_SORT_HINT(de) 0
  40 #else
  41 #define SORT_DIRENT 1
  42 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
  43 #endif
  44
  45 static void objreport(struct object *obj, const char *severity,
  46                       const char *err, va_list params)
  47 {
  48         fprintf(stderr, "%s in %s %s: ",
  49                 severity, typename(obj->type), sha1_to_hex(obj->sha1));
  50         vfprintf(stderr, err, params);
  51         fputs("\n", stderr);
  52 }
  53
  54 __attribute__((format (printf, 2, 3)))
  55 static int objerror(struct object *obj, const char *err, ...)
  56 {
  57         va_list params;
  58         va_start(params, err);
  59         errors_found |= ERROR_OBJECT;
  60         objreport(obj, "error", err, params);
  61         va_end(params);
  62         return -1;
  63 }
  64
  65 __attribute__((format (printf, 3, 4)))
  66 static int fsck_error_func(struct object *obj, int type, const char *err, ...)
  67 {
  68         va_list params;
  69         va_start(params, err);
  70         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", err, params);
  71         va_end(params);
  72         return (type == FSCK_WARN) ? 0 : 1;
  73 }
  74
  75 static struct object_array pending;
  76
  77 static int mark_object(struct object *obj, int type, void *data)
  78 {
  79         struct object *parent = data;
  80
  81         /*
  82          * The only case data is NULL or type is OBJ_ANY is when
  83          * mark_object_reachable() calls us.  All the callers of
  84          * that function has non-NULL obj hence ...
  85          */
  86         if (!obj) {
  87                 /* ... these references to parent->fld are safe here */
  88                 printf("broken link from %7s %s\n",
  89                            typename(parent->type), sha1_to_hex(parent->sha1));
  90                 printf("broken link from %7s %s\n",
  91                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
  92                 errors_found |= ERROR_REACHABLE;
  93                 return 1;
  94         }
  95
  96         if (type != OBJ_ANY && obj->type != type)
  97                 /* ... and the reference to parent is safe here */
  98                 objerror(parent, "wrong object type in link");
  99
 100         if (obj->flags & REACHABLE)
 101                 return 0;
 102         obj->flags |= REACHABLE;
 103         if (!obj->parsed) {
 104                 if (parent && !has_sha1_file(obj->sha1)) {
 105                         printf("broken link from %7s %s\n",
 106                                  typename(parent->type), sha1_to_hex(parent->sha1));
 107                         printf("              to %7s %s\n",
 108                                  typename(obj->type), sha1_to_hex(obj->sha1));
 109                         errors_found |= ERROR_REACHABLE;
 110                 }
 111                 return 1;
 112         }
 113
 114         add_object_array(obj, (void *) parent, &pending);
 115         return 0;
 116 }
 117
 118 static void mark_object_reachable(struct object *obj)
 119 {
 120         mark_object(obj, OBJ_ANY, NULL);
 121 }
 122
 123 static int traverse_one_object(struct object *obj)
 124 {
 125         int result;
 126         struct tree *tree = NULL;
 127
 128         if (obj->type == OBJ_TREE) {
 129                 obj->parsed = 0;
 130                 tree = (struct tree *)obj;
 131                 if (parse_tree(tree) < 0)
 132                         return 1; /* error already displayed */
 133         }
 134         result = fsck_walk(obj, mark_object, obj);
 135         if (tree) {
 136                 free(tree->buffer);
 137                 tree->buffer = NULL;
 138         }
 139         return result;
 140 }
 141
 142 static int traverse_reachable(void)
 143 {
 144         struct progress *progress = NULL;
 145         unsigned int nr = 0;
 146         int result = 0;
 147         if (show_progress)
 148                 progress = start_progress_delay("Checking connectivity", 0, 0, 2);
 149         while (pending.nr) {
 150                 struct object_array_entry *entry;
 151                 struct object *obj;
 152
 153                 entry = pending.objects + --pending.nr;
 154                 obj = entry->item;
 155                 result |= traverse_one_object(obj);
 156                 display_progress(progress, ++nr);
 157         }
 158         stop_progress(&progress);
 159         return !!result;
 160 }
 161
 162 static int mark_used(struct object *obj, int type, void *data)
 163 {
 164         if (!obj)
 165                 return 1;
 166         obj->used = 1;
 167         return 0;
 168 }
 169
 170 /*
 171  * Check a single reachable object
 172  */
 173 static void check_reachable_object(struct object *obj)
 174 {
 175         /*
 176          * We obviously want the object to be parsed,
 177          * except if it was in a pack-file and we didn't
 178          * do a full fsck
 179          */
 180         if (!obj->parsed) {
 181                 if (has_sha1_pack(obj->sha1))
 182                         return; /* it is in pack - forget about it */
 183                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 184                 errors_found |= ERROR_REACHABLE;
 185                 return;
 186         }
 187 }
 188
 189 /*
 190  * Check a single unreachable object
 191  */
 192 static void check_unreachable_object(struct object *obj)
 193 {
 194         /*
 195          * Missing unreachable object? Ignore it. It's not like
 196          * we miss it (since it can't be reached), nor do we want
 197          * to complain about it being unreachable (since it does
 198          * not exist).
 199          */
 200         if (!obj->parsed)
 201                 return;
 202
 203         /*
 204          * Unreachable object that exists? Show it if asked to,
 205          * since this is something that is prunable.
 206          */
 207         if (show_unreachable) {
 208                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 209                 return;
 210         }
 211
 212         /*
 213          * "!used" means that nothing at all points to it, including
 214          * other unreachable objects. In other words, it's the "tip"
 215          * of some set of unreachable objects, usually a commit that
 216          * got dropped.
 217          *
 218          * Such starting points are more interesting than some random
 219          * set of unreachable objects, so we show them even if the user
 220          * hasn't asked for _all_ unreachable objects. If you have
 221          * deleted a branch by mistake, this is a prime candidate to
 222          * start looking at, for example.
 223          */
 224         if (!obj->used) {
 225                 if (show_dangling)
 226                         printf("dangling %s %s\n", typename(obj->type),
 227                                sha1_to_hex(obj->sha1));
 228                 if (write_lost_and_found) {
 229                         char *filename = git_path("lost-found/%s/%s",
 230                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 231                                 sha1_to_hex(obj->sha1));
 232                         FILE *f;
 233
 234                         if (safe_create_leading_directories(filename)) {
 235                                 error("Could not create lost-found");
 236                                 return;
 237                         }
 238                         if (!(f = fopen(filename, "w")))
 239                                 die_errno("Could not open '%s'", filename);
 240                         if (obj->type == OBJ_BLOB) {
 241                                 enum object_type type;
 242                                 unsigned long size;
 243                                 char *buf = read_sha1_file(obj->sha1,
 244                                                 &type, &size);
 245                                 if (buf && fwrite(buf, 1, size, f) != size)
 246                                         die_errno("Could not write '%s'", filename);
 247                                 free(buf);
 248                         } else
 249                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 250                         if (fclose(f))
 251                                 die_errno("Could not finish '%s'",
 252                                           filename);
 253                 }
 254                 return;
 255         }
 256
 257         /*
 258          * Otherwise? It's there, it's unreachable, and some other unreachable
 259          * object points to it. Ignore it - it's not interesting, and we showed
 260          * all the interesting cases above.
 261          */
 262 }
 263
 264 static void check_object(struct object *obj)
 265 {
 266         if (verbose)
 267                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 268
 269         if (obj->flags & REACHABLE)
 270                 check_reachable_object(obj);
 271         else
 272                 check_unreachable_object(obj);
 273 }
 274
 275 static void check_connectivity(void)
 276 {
 277         int i, max;
 278
 279         /* Traverse the pending reachable objects */
 280         traverse_reachable();
 281
 282         /* Look up all the requirements, warn about missing objects.. */
 283         max = get_max_object_index();
 284         if (verbose)
 285                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 286
 287         for (i = 0; i < max; i++) {
 288                 struct object *obj = get_indexed_object(i);
 289
 290                 if (obj)
 291                         check_object(obj);
 292         }
 293 }
 294
 295 static int fsck_obj(struct object *obj)
 296 {
 297         if (obj->flags & SEEN)
 298                 return 0;
 299         obj->flags |= SEEN;
 300
 301         if (verbose)
 302                 fprintf(stderr, "Checking %s %s\n",
 303                         typename(obj->type), sha1_to_hex(obj->sha1));
 304
 305         if (fsck_walk(obj, mark_used, NULL))
 306                 objerror(obj, "broken links");
 307         if (fsck_object(obj, check_strict, fsck_error_func))
 308                 return -1;
 309
 310         if (obj->type == OBJ_TREE) {
 311                 struct tree *item = (struct tree *) obj;
 312
 313                 free(item->buffer);
 314                 item->buffer = NULL;
 315         }
 316
 317         if (obj->type == OBJ_COMMIT) {
 318                 struct commit *commit = (struct commit *) obj;
 319
 320                 free(commit->buffer);
 321                 commit->buffer = NULL;
 322
 323                 if (!commit->parents && show_root)
 324                         printf("root %s\n", sha1_to_hex(commit->object.sha1));
 325         }
 326
 327         if (obj->type == OBJ_TAG) {
 328                 struct tag *tag = (struct tag *) obj;
 329
 330                 if (show_tags && tag->tagged) {
 331                         printf("tagged %s %s", typename(tag->tagged->type), sha1_to_hex(tag->tagged->sha1));
 332                         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 333                 }
 334         }
 335
 336         return 0;
 337 }
 338
 339 static int fsck_sha1(const unsigned char *sha1)
 340 {
 341         struct object *obj = parse_object(sha1);
 342         if (!obj) {
 343                 errors_found |= ERROR_OBJECT;
 344                 return error("%s: object corrupt or missing",
 345                              sha1_to_hex(sha1));
 346         }
 347         return fsck_obj(obj);
 348 }
 349
 350 static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 351                            unsigned long size, void *buffer, int *eaten)
 352 {
 353         struct object *obj;
 354         obj = parse_object_buffer(sha1, type, size, buffer, eaten);
 355         if (!obj) {
 356                 errors_found |= ERROR_OBJECT;
 357                 return error("%s: object corrupt or missing", sha1_to_hex(sha1));
 358         }
 359         return fsck_obj(obj);
 360 }
 361
 362 /*
 363  * This is the sorting chunk size: make it reasonably
 364  * big so that we can sort well..
 365  */
 366 #define MAX_SHA1_ENTRIES (1024)
 367
 368 struct sha1_entry {
 369         unsigned long ino;
 370         unsigned char sha1[20];
 371 };
 372
 373 static struct {
 374         unsigned long nr;
 375         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 376 } sha1_list;
 377
 378 static int ino_compare(const void *_a, const void *_b)
 379 {
 380         const struct sha1_entry *a = _a, *b = _b;
 381         unsigned long ino1 = a->ino, ino2 = b->ino;
 382         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 383 }
 384
 385 static void fsck_sha1_list(void)
 386 {
 387         int i, nr = sha1_list.nr;
 388
 389         if (SORT_DIRENT)
 390                 qsort(sha1_list.entry, nr,
 391                       sizeof(struct sha1_entry *), ino_compare);
 392         for (i = 0; i < nr; i++) {
 393                 struct sha1_entry *entry = sha1_list.entry[i];
 394                 unsigned char *sha1 = entry->sha1;
 395
 396                 sha1_list.entry[i] = NULL;
 397                 fsck_sha1(sha1);
 398                 free(entry);
 399         }
 400         sha1_list.nr = 0;
 401 }
 402
 403 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 404 {
 405         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 406         int nr;
 407
 408         entry->ino = ino;
 409         hashcpy(entry->sha1, sha1);
 410         nr = sha1_list.nr;
 411         if (nr == MAX_SHA1_ENTRIES) {
 412                 fsck_sha1_list();
 413                 nr = 0;
 414         }
 415         sha1_list.entry[nr] = entry;
 416         sha1_list.nr = ++nr;
 417 }
 418
 419 static inline int is_loose_object_file(struct dirent *de,
 420                                        char *name, unsigned char *sha1)
 421 {
 422         if (strlen(de->d_name) != 38)
 423                 return 0;
 424         memcpy(name + 2, de->d_name, 39);
 425         return !get_sha1_hex(name, sha1);
 426 }
 427
 428 static void fsck_dir(int i, char *path)
 429 {
 430         DIR *dir = opendir(path);
 431         struct dirent *de;
 432         char name[100];
 433
 434         if (!dir)
 435                 return;
 436
 437         if (verbose)
 438                 fprintf(stderr, "Checking directory %s\n", path);
 439
 440         sprintf(name, "%02x", i);
 441         while ((de = readdir(dir)) != NULL) {
 442                 unsigned char sha1[20];
 443
 444                 if (is_dot_or_dotdot(de->d_name))
 445                         continue;
 446                 if (is_loose_object_file(de, name, sha1)) {
 447                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 448                         continue;
 449                 }
 450                 if (!prefixcmp(de->d_name, "tmp_obj_"))
 451                         continue;
 452                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 453         }
 454         closedir(dir);
 455 }
 456
 457 static int default_refs;
 458
 459 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 460                 const char *email, unsigned long timestamp, int tz,
 461                 const char *message, void *cb_data)
 462 {
 463         struct object *obj;
 464
 465         if (verbose)
 466                 fprintf(stderr, "Checking reflog %s->%s\n",
 467                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 468
 469         if (!is_null_sha1(osha1)) {
 470                 obj = lookup_object(osha1);
 471                 if (obj) {
 472                         obj->used = 1;
 473                         mark_object_reachable(obj);
 474                 }
 475         }
 476         obj = lookup_object(nsha1);
 477         if (obj) {
 478                 obj->used = 1;
 479                 mark_object_reachable(obj);
 480         }
 481         return 0;
 482 }
 483
 484 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 485 {
 486         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 487         return 0;
 488 }
 489
 490 static int is_branch(const char *refname)
 491 {
 492         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 493 }
 494
 495 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 496 {
 497         struct object *obj;
 498
 499         obj = parse_object(sha1);
 500         if (!obj) {
 501                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 502                 /* We'll continue with the rest despite the error.. */
 503                 return 0;
 504         }
 505         if (obj->type != OBJ_COMMIT && is_branch(refname))
 506                 error("%s: not a commit", refname);
 507         default_refs++;
 508         obj->used = 1;
 509         mark_object_reachable(obj);
 510
 511         return 0;
 512 }
 513
 514 static void get_default_heads(void)
 515 {
 516         if (head_points_at && !is_null_sha1(head_sha1))
 517                 fsck_handle_ref("HEAD", head_sha1, 0, NULL);
 518         for_each_ref(fsck_handle_ref, NULL);
 519         if (include_reflogs)
 520                 for_each_reflog(fsck_handle_reflog, NULL);
 521
 522         /*
 523          * Not having any default heads isn't really fatal, but
 524          * it does mean that "--unreachable" no longer makes any
 525          * sense (since in this case everything will obviously
 526          * be unreachable by definition.
 527          *
 528          * Showing dangling objects is valid, though (as those
 529          * dangling objects are likely lost heads).
 530          *
 531          * So we just print a warning about it, and clear the
 532          * "show_unreachable" flag.
 533          */
 534         if (!default_refs) {
 535                 fprintf(stderr, "notice: No default references\n");
 536                 show_unreachable = 0;
 537         }
 538 }
 539
 540 static void fsck_object_dir(const char *path)
 541 {
 542         int i;
 543         struct progress *progress = NULL;
 544
 545         if (verbose)
 546                 fprintf(stderr, "Checking object directory\n");
 547
 548         if (show_progress)
 549                 progress = start_progress("Checking object directories", 256);
 550         for (i = 0; i < 256; i++) {
 551                 static char dir[4096];
 552                 sprintf(dir, "%s/%02x", path, i);
 553                 fsck_dir(i, dir);
 554                 display_progress(progress, i+1);
 555         }
 556         stop_progress(&progress);
 557         fsck_sha1_list();
 558 }
 559
 560 static int fsck_head_link(void)
 561 {
 562         int flag;
 563         int null_is_error = 0;
 564
 565         if (verbose)
 566                 fprintf(stderr, "Checking HEAD link\n");
 567
 568         head_points_at = resolve_ref_unsafe("HEAD", head_sha1, 0, &flag);
 569         if (!head_points_at)
 570                 return error("Invalid HEAD");
 571         if (!strcmp(head_points_at, "HEAD"))
 572                 /* detached HEAD */
 573                 null_is_error = 1;
 574         else if (prefixcmp(head_points_at, "refs/heads/"))
 575                 return error("HEAD points to something strange (%s)",
 576                              head_points_at);
 577         if (is_null_sha1(head_sha1)) {
 578                 if (null_is_error)
 579                         return error("HEAD: detached HEAD points at nothing");
 580                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 581                         head_points_at + 11);
 582         }
 583         return 0;
 584 }
 585
 586 static int fsck_cache_tree(struct cache_tree *it)
 587 {
 588         int i;
 589         int err = 0;
 590
 591         if (verbose)
 592                 fprintf(stderr, "Checking cache tree\n");
 593
 594         if (0 <= it->entry_count) {
 595                 struct object *obj = parse_object(it->sha1);
 596                 if (!obj) {
 597                         error("%s: invalid sha1 pointer in cache-tree",
 598                               sha1_to_hex(it->sha1));
 599                         return 1;
 600                 }
 601                 obj->used = 1;
 602                 mark_object_reachable(obj);
 603                 if (obj->type != OBJ_TREE)
 604                         err |= objerror(obj, "non-tree in cache-tree");
 605         }
 606         for (i = 0; i < it->subtree_nr; i++)
 607                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 608         return err;
 609 }
 610
 611 static char const * const fsck_usage[] = {
 612         "git fsck [options] [<object>...]",
 613         NULL
 614 };
 615
 616 static struct option fsck_opts[] = {
 617         OPT__VERBOSE(&verbose, "be verbose"),
 618         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 619         OPT_BOOL(0, "dangling", &show_dangling, "show dangling objects"),
 620         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 621         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 622         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 623         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 624         OPT_BOOLEAN(0, "full", &check_full, "also consider packs and alternate objects"),
 625         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 626         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 627                                 "write dangling objects in .git/lost-found"),
 628         OPT_BOOL(0, "progress", &show_progress, "show progress"),
 629         OPT_END(),
 630 };
 631
 632 int cmd_fsck(int argc, const char **argv, const char *prefix)
 633 {
 634         int i, heads;
 635         struct alternate_object_database *alt;
 636
 637         errors_found = 0;
 638         read_replace_refs = 0;
 639
 640         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 641
 642         if (show_progress == -1)
 643                 show_progress = isatty(2);
 644         if (verbose)
 645                 show_progress = 0;
 646
 647         if (write_lost_and_found) {
 648                 check_full = 1;
 649                 include_reflogs = 0;
 650         }
 651
 652         fsck_head_link();
 653         fsck_object_dir(get_object_directory());
 654
 655         prepare_alt_odb();
 656         for (alt = alt_odb_list; alt; alt = alt->next) {
 657                 char namebuf[PATH_MAX];
 658                 int namelen = alt->name - alt->base;
 659                 memcpy(namebuf, alt->base, namelen);
 660                 namebuf[namelen - 1] = 0;
 661                 fsck_object_dir(namebuf);
 662         }
 663
 664         if (check_full) {
 665                 struct packed_git *p;
 666                 uint32_t total = 0, count = 0;
 667                 struct progress *progress = NULL;
 668
 669                 prepare_packed_git();
 670
 671                 if (show_progress) {
 672                         for (p = packed_git; p; p = p->next) {
 673                                 if (open_pack_index(p))
 674                                         continue;
 675                                 total += p->num_objects;
 676                         }
 677
 678                         progress = start_progress("Checking objects", total);
 679                 }
 680                 for (p = packed_git; p; p = p->next) {
 681                         /* verify gives error messages itself */
 682                         if (verify_pack(p, fsck_obj_buffer,
 683                                         progress, count))
 684                                 errors_found |= ERROR_PACK;
 685                         count += p->num_objects;
 686                 }
 687                 stop_progress(&progress);
 688         }
 689
 690         heads = 0;
 691         for (i = 0; i < argc; i++) {
 692                 const char *arg = argv[i];
 693                 unsigned char sha1[20];
 694                 if (!get_sha1(arg, sha1)) {
 695                         struct object *obj = lookup_object(sha1);
 696
 697                         /* Error is printed by lookup_object(). */
 698                         if (!obj)
 699                                 continue;
 700
 701                         obj->used = 1;
 702                         mark_object_reachable(obj);
 703                         heads++;
 704                         continue;
 705                 }
 706                 error("invalid parameter: expected sha1, got '%s'", arg);
 707         }
 708
 709         /*
 710          * If we've not been given any explicit head information, do the
 711          * default ones from .git/refs. We also consider the index file
 712          * in this case (ie this implies --cache).
 713          */
 714         if (!heads) {
 715                 get_default_heads();
 716                 keep_cache_objects = 1;
 717         }
 718
 719         if (keep_cache_objects) {
 720                 read_cache();
 721                 for (i = 0; i < active_nr; i++) {
 722                         unsigned int mode;
 723                         struct blob *blob;
 724                         struct object *obj;
 725
 726                         mode = active_cache[i]->ce_mode;
 727                         if (S_ISGITLINK(mode))
 728                                 continue;
 729                         blob = lookup_blob(active_cache[i]->sha1);
 730                         if (!blob)
 731                                 continue;
 732                         obj = &blob->object;
 733                         obj->used = 1;
 734                         mark_object_reachable(obj);
 735                 }
 736                 if (active_cache_tree)
 737                         fsck_cache_tree(active_cache_tree);
 738         }
 739
 740         check_connectivity();
 741         return errors_found;
 742 }