Merge branch 'jk/delete-modechange-conflict' into maint
[git] / 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 #include "streaming.h"
16
17 #define REACHABLE 0x0001
18 #define SEEN      0x0002
19 #define HAS_OBJ   0x0004
20
21 static int show_root;
22 static int show_tags;
23 static int show_unreachable;
24 static int include_reflogs = 1;
25 static int check_full = 1;
26 static int connectivity_only;
27 static int check_strict;
28 static int keep_cache_objects;
29 static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
30 static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
31 static struct object_id head_oid;
32 static const char *head_points_at;
33 static int errors_found;
34 static int write_lost_and_found;
35 static int verbose;
36 static int show_progress = -1;
37 static int show_dangling = 1;
38 #define ERROR_OBJECT 01
39 #define ERROR_REACHABLE 02
40 #define ERROR_PACK 04
41 #define ERROR_REFS 010
42
43 #ifdef NO_D_INO_IN_DIRENT
44 #define SORT_DIRENT 0
45 #define DIRENT_SORT_HINT(de) 0
46 #else
47 #define SORT_DIRENT 1
48 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
49 #endif
50
51 static int fsck_config(const char *var, const char *value, void *cb)
52 {
53         if (strcmp(var, "fsck.skiplist") == 0) {
54                 const char *path;
55                 struct strbuf sb = STRBUF_INIT;
56
57                 if (git_config_pathname(&path, var, value))
58                         return 1;
59                 strbuf_addf(&sb, "skiplist=%s", path);
60                 free((char *)path);
61                 fsck_set_msg_types(&fsck_obj_options, sb.buf);
62                 strbuf_release(&sb);
63                 return 0;
64         }
65
66         if (skip_prefix(var, "fsck.", &var)) {
67                 fsck_set_msg_type(&fsck_obj_options, var, value);
68                 return 0;
69         }
70
71         return git_default_config(var, value, cb);
72 }
73
74 static void objreport(struct object *obj, const char *msg_type,
75                         const char *err)
76 {
77         fprintf(stderr, "%s in %s %s: %s\n",
78                 msg_type, typename(obj->type), sha1_to_hex(obj->sha1), err);
79 }
80
81 static int objerror(struct object *obj, const char *err)
82 {
83         errors_found |= ERROR_OBJECT;
84         objreport(obj, "error", err);
85         return -1;
86 }
87
88 static int fsck_error_func(struct object *obj, int type, const char *message)
89 {
90         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", message);
91         return (type == FSCK_WARN) ? 0 : 1;
92 }
93
94 static struct object_array pending;
95
96 static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
97 {
98         struct object *parent = data;
99
100         /*
101          * The only case data is NULL or type is OBJ_ANY is when
102          * mark_object_reachable() calls us.  All the callers of
103          * that function has non-NULL obj hence ...
104          */
105         if (!obj) {
106                 /* ... these references to parent->fld are safe here */
107                 printf("broken link from %7s %s\n",
108                            typename(parent->type), sha1_to_hex(parent->sha1));
109                 printf("broken link from %7s %s\n",
110                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
111                 errors_found |= ERROR_REACHABLE;
112                 return 1;
113         }
114
115         if (type != OBJ_ANY && obj->type != type)
116                 /* ... and the reference to parent is safe here */
117                 objerror(parent, "wrong object type in link");
118
119         if (obj->flags & REACHABLE)
120                 return 0;
121         obj->flags |= REACHABLE;
122         if (!(obj->flags & HAS_OBJ)) {
123                 if (parent && !has_sha1_file(obj->sha1)) {
124                         printf("broken link from %7s %s\n",
125                                  typename(parent->type), sha1_to_hex(parent->sha1));
126                         printf("              to %7s %s\n",
127                                  typename(obj->type), sha1_to_hex(obj->sha1));
128                         errors_found |= ERROR_REACHABLE;
129                 }
130                 return 1;
131         }
132
133         add_object_array(obj, NULL, &pending);
134         return 0;
135 }
136
137 static void mark_object_reachable(struct object *obj)
138 {
139         mark_object(obj, OBJ_ANY, NULL, NULL);
140 }
141
142 static int traverse_one_object(struct object *obj)
143 {
144         int result;
145         struct tree *tree = NULL;
146
147         if (obj->type == OBJ_TREE) {
148                 tree = (struct tree *)obj;
149                 if (parse_tree(tree) < 0)
150                         return 1; /* error already displayed */
151         }
152         result = fsck_walk(obj, obj, &fsck_walk_options);
153         if (tree)
154                 free_tree_buffer(tree);
155         return result;
156 }
157
158 static int traverse_reachable(void)
159 {
160         struct progress *progress = NULL;
161         unsigned int nr = 0;
162         int result = 0;
163         if (show_progress)
164                 progress = start_progress_delay(_("Checking connectivity"), 0, 0, 2);
165         while (pending.nr) {
166                 struct object_array_entry *entry;
167                 struct object *obj;
168
169                 entry = pending.objects + --pending.nr;
170                 obj = entry->item;
171                 result |= traverse_one_object(obj);
172                 display_progress(progress, ++nr);
173         }
174         stop_progress(&progress);
175         return !!result;
176 }
177
178 static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
179 {
180         if (!obj)
181                 return 1;
182         obj->used = 1;
183         return 0;
184 }
185
186 /*
187  * Check a single reachable object
188  */
189 static void check_reachable_object(struct object *obj)
190 {
191         /*
192          * We obviously want the object to be parsed,
193          * except if it was in a pack-file and we didn't
194          * do a full fsck
195          */
196         if (!(obj->flags & HAS_OBJ)) {
197                 if (has_sha1_pack(obj->sha1))
198                         return; /* it is in pack - forget about it */
199                 if (connectivity_only && has_sha1_file(obj->sha1))
200                         return;
201                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
202                 errors_found |= ERROR_REACHABLE;
203                 return;
204         }
205 }
206
207 /*
208  * Check a single unreachable object
209  */
210 static void check_unreachable_object(struct object *obj)
211 {
212         /*
213          * Missing unreachable object? Ignore it. It's not like
214          * we miss it (since it can't be reached), nor do we want
215          * to complain about it being unreachable (since it does
216          * not exist).
217          */
218         if (!obj->parsed)
219                 return;
220
221         /*
222          * Unreachable object that exists? Show it if asked to,
223          * since this is something that is prunable.
224          */
225         if (show_unreachable) {
226                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
227                 return;
228         }
229
230         /*
231          * "!used" means that nothing at all points to it, including
232          * other unreachable objects. In other words, it's the "tip"
233          * of some set of unreachable objects, usually a commit that
234          * got dropped.
235          *
236          * Such starting points are more interesting than some random
237          * set of unreachable objects, so we show them even if the user
238          * hasn't asked for _all_ unreachable objects. If you have
239          * deleted a branch by mistake, this is a prime candidate to
240          * start looking at, for example.
241          */
242         if (!obj->used) {
243                 if (show_dangling)
244                         printf("dangling %s %s\n", typename(obj->type),
245                                sha1_to_hex(obj->sha1));
246                 if (write_lost_and_found) {
247                         char *filename = git_pathdup("lost-found/%s/%s",
248                                 obj->type == OBJ_COMMIT ? "commit" : "other",
249                                 sha1_to_hex(obj->sha1));
250                         FILE *f;
251
252                         if (safe_create_leading_directories_const(filename)) {
253                                 error("Could not create lost-found");
254                                 free(filename);
255                                 return;
256                         }
257                         if (!(f = fopen(filename, "w")))
258                                 die_errno("Could not open '%s'", filename);
259                         if (obj->type == OBJ_BLOB) {
260                                 if (stream_blob_to_fd(fileno(f), obj->sha1, NULL, 1))
261                                         die_errno("Could not write '%s'", filename);
262                         } else
263                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
264                         if (fclose(f))
265                                 die_errno("Could not finish '%s'",
266                                           filename);
267                         free(filename);
268                 }
269                 return;
270         }
271
272         /*
273          * Otherwise? It's there, it's unreachable, and some other unreachable
274          * object points to it. Ignore it - it's not interesting, and we showed
275          * all the interesting cases above.
276          */
277 }
278
279 static void check_object(struct object *obj)
280 {
281         if (verbose)
282                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
283
284         if (obj->flags & REACHABLE)
285                 check_reachable_object(obj);
286         else
287                 check_unreachable_object(obj);
288 }
289
290 static void check_connectivity(void)
291 {
292         int i, max;
293
294         /* Traverse the pending reachable objects */
295         traverse_reachable();
296
297         /* Look up all the requirements, warn about missing objects.. */
298         max = get_max_object_index();
299         if (verbose)
300                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
301
302         for (i = 0; i < max; i++) {
303                 struct object *obj = get_indexed_object(i);
304
305                 if (obj)
306                         check_object(obj);
307         }
308 }
309
310 static int fsck_obj(struct object *obj)
311 {
312         if (obj->flags & SEEN)
313                 return 0;
314         obj->flags |= SEEN;
315
316         if (verbose)
317                 fprintf(stderr, "Checking %s %s\n",
318                         typename(obj->type), sha1_to_hex(obj->sha1));
319
320         if (fsck_walk(obj, NULL, &fsck_obj_options))
321                 objerror(obj, "broken links");
322         if (fsck_object(obj, NULL, 0, &fsck_obj_options))
323                 return -1;
324
325         if (obj->type == OBJ_TREE) {
326                 struct tree *item = (struct tree *) obj;
327
328                 free_tree_buffer(item);
329         }
330
331         if (obj->type == OBJ_COMMIT) {
332                 struct commit *commit = (struct commit *) obj;
333
334                 free_commit_buffer(commit);
335
336                 if (!commit->parents && show_root)
337                         printf("root %s\n", sha1_to_hex(commit->object.sha1));
338         }
339
340         if (obj->type == OBJ_TAG) {
341                 struct tag *tag = (struct tag *) obj;
342
343                 if (show_tags && tag->tagged) {
344                         printf("tagged %s %s", typename(tag->tagged->type), sha1_to_hex(tag->tagged->sha1));
345                         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
346                 }
347         }
348
349         return 0;
350 }
351
352 static int fsck_sha1(const unsigned char *sha1)
353 {
354         struct object *obj = parse_object(sha1);
355         if (!obj) {
356                 errors_found |= ERROR_OBJECT;
357                 return error("%s: object corrupt or missing",
358                              sha1_to_hex(sha1));
359         }
360         obj->flags |= HAS_OBJ;
361         return fsck_obj(obj);
362 }
363
364 static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
365                            unsigned long size, void *buffer, int *eaten)
366 {
367         struct object *obj;
368         obj = parse_object_buffer(sha1, type, size, buffer, eaten);
369         if (!obj) {
370                 errors_found |= ERROR_OBJECT;
371                 return error("%s: object corrupt or missing", sha1_to_hex(sha1));
372         }
373         obj->flags = HAS_OBJ;
374         return fsck_obj(obj);
375 }
376
377 /*
378  * This is the sorting chunk size: make it reasonably
379  * big so that we can sort well..
380  */
381 #define MAX_SHA1_ENTRIES (1024)
382
383 struct sha1_entry {
384         unsigned long ino;
385         unsigned char sha1[20];
386 };
387
388 static struct {
389         unsigned long nr;
390         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
391 } sha1_list;
392
393 static int ino_compare(const void *_a, const void *_b)
394 {
395         const struct sha1_entry *a = _a, *b = _b;
396         unsigned long ino1 = a->ino, ino2 = b->ino;
397         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
398 }
399
400 static void fsck_sha1_list(void)
401 {
402         int i, nr = sha1_list.nr;
403
404         if (SORT_DIRENT)
405                 qsort(sha1_list.entry, nr,
406                       sizeof(struct sha1_entry *), ino_compare);
407         for (i = 0; i < nr; i++) {
408                 struct sha1_entry *entry = sha1_list.entry[i];
409                 unsigned char *sha1 = entry->sha1;
410
411                 sha1_list.entry[i] = NULL;
412                 if (fsck_sha1(sha1))
413                         errors_found |= ERROR_OBJECT;
414                 free(entry);
415         }
416         sha1_list.nr = 0;
417 }
418
419 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
420 {
421         struct sha1_entry *entry = xmalloc(sizeof(*entry));
422         int nr;
423
424         entry->ino = ino;
425         hashcpy(entry->sha1, sha1);
426         nr = sha1_list.nr;
427         if (nr == MAX_SHA1_ENTRIES) {
428                 fsck_sha1_list();
429                 nr = 0;
430         }
431         sha1_list.entry[nr] = entry;
432         sha1_list.nr = ++nr;
433 }
434
435 static inline int is_loose_object_file(struct dirent *de,
436                                        char *name, unsigned char *sha1)
437 {
438         if (strlen(de->d_name) != 38)
439                 return 0;
440         memcpy(name + 2, de->d_name, 39);
441         return !get_sha1_hex(name, sha1);
442 }
443
444 static void fsck_dir(int i, char *path)
445 {
446         DIR *dir = opendir(path);
447         struct dirent *de;
448         char name[100];
449
450         if (!dir)
451                 return;
452
453         if (verbose)
454                 fprintf(stderr, "Checking directory %s\n", path);
455
456         sprintf(name, "%02x", i);
457         while ((de = readdir(dir)) != NULL) {
458                 unsigned char sha1[20];
459
460                 if (is_dot_or_dotdot(de->d_name))
461                         continue;
462                 if (is_loose_object_file(de, name, sha1)) {
463                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
464                         continue;
465                 }
466                 if (starts_with(de->d_name, "tmp_obj_"))
467                         continue;
468                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
469         }
470         closedir(dir);
471 }
472
473 static int default_refs;
474
475 static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1)
476 {
477         struct object *obj;
478
479         if (!is_null_sha1(sha1)) {
480                 obj = lookup_object(sha1);
481                 if (obj) {
482                         obj->used = 1;
483                         mark_object_reachable(obj);
484                 } else {
485                         error("%s: invalid reflog entry %s", refname, sha1_to_hex(sha1));
486                         errors_found |= ERROR_REACHABLE;
487                 }
488         }
489 }
490
491 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
492                 const char *email, unsigned long timestamp, int tz,
493                 const char *message, void *cb_data)
494 {
495         const char *refname = cb_data;
496
497         if (verbose)
498                 fprintf(stderr, "Checking reflog %s->%s\n",
499                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
500
501         fsck_handle_reflog_sha1(refname, osha1);
502         fsck_handle_reflog_sha1(refname, nsha1);
503         return 0;
504 }
505
506 static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
507                               int flag, void *cb_data)
508 {
509         for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
510         return 0;
511 }
512
513 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
514                            int flag, void *cb_data)
515 {
516         struct object *obj;
517
518         obj = parse_object(oid->hash);
519         if (!obj) {
520                 error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
521                 errors_found |= ERROR_REACHABLE;
522                 /* We'll continue with the rest despite the error.. */
523                 return 0;
524         }
525         if (obj->type != OBJ_COMMIT && is_branch(refname)) {
526                 error("%s: not a commit", refname);
527                 errors_found |= ERROR_REFS;
528         }
529         default_refs++;
530         obj->used = 1;
531         mark_object_reachable(obj);
532
533         return 0;
534 }
535
536 static void get_default_heads(void)
537 {
538         if (head_points_at && !is_null_oid(&head_oid))
539                 fsck_handle_ref("HEAD", &head_oid, 0, NULL);
540         for_each_rawref(fsck_handle_ref, NULL);
541         if (include_reflogs)
542                 for_each_reflog(fsck_handle_reflog, NULL);
543
544         /*
545          * Not having any default heads isn't really fatal, but
546          * it does mean that "--unreachable" no longer makes any
547          * sense (since in this case everything will obviously
548          * be unreachable by definition.
549          *
550          * Showing dangling objects is valid, though (as those
551          * dangling objects are likely lost heads).
552          *
553          * So we just print a warning about it, and clear the
554          * "show_unreachable" flag.
555          */
556         if (!default_refs) {
557                 fprintf(stderr, "notice: No default references\n");
558                 show_unreachable = 0;
559         }
560 }
561
562 static void fsck_object_dir(const char *path)
563 {
564         int i;
565         struct progress *progress = NULL;
566
567         if (verbose)
568                 fprintf(stderr, "Checking object directory\n");
569
570         if (show_progress)
571                 progress = start_progress(_("Checking object directories"), 256);
572         for (i = 0; i < 256; i++) {
573                 static char dir[4096];
574                 sprintf(dir, "%s/%02x", path, i);
575                 fsck_dir(i, dir);
576                 display_progress(progress, i+1);
577         }
578         stop_progress(&progress);
579         fsck_sha1_list();
580 }
581
582 static int fsck_head_link(void)
583 {
584         int flag;
585         int null_is_error = 0;
586
587         if (verbose)
588                 fprintf(stderr, "Checking HEAD link\n");
589
590         head_points_at = resolve_ref_unsafe("HEAD", 0, head_oid.hash, &flag);
591         if (!head_points_at) {
592                 errors_found |= ERROR_REFS;
593                 return error("Invalid HEAD");
594         }
595         if (!strcmp(head_points_at, "HEAD"))
596                 /* detached HEAD */
597                 null_is_error = 1;
598         else if (!starts_with(head_points_at, "refs/heads/")) {
599                 errors_found |= ERROR_REFS;
600                 return error("HEAD points to something strange (%s)",
601                              head_points_at);
602         }
603         if (is_null_oid(&head_oid)) {
604                 if (null_is_error) {
605                         errors_found |= ERROR_REFS;
606                         return error("HEAD: detached HEAD points at nothing");
607                 }
608                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
609                         head_points_at + 11);
610         }
611         return 0;
612 }
613
614 static int fsck_cache_tree(struct cache_tree *it)
615 {
616         int i;
617         int err = 0;
618
619         if (verbose)
620                 fprintf(stderr, "Checking cache tree\n");
621
622         if (0 <= it->entry_count) {
623                 struct object *obj = parse_object(it->sha1);
624                 if (!obj) {
625                         error("%s: invalid sha1 pointer in cache-tree",
626                               sha1_to_hex(it->sha1));
627                         errors_found |= ERROR_REFS;
628                         return 1;
629                 }
630                 obj->used = 1;
631                 mark_object_reachable(obj);
632                 if (obj->type != OBJ_TREE)
633                         err |= objerror(obj, "non-tree in cache-tree");
634         }
635         for (i = 0; i < it->subtree_nr; i++)
636                 err |= fsck_cache_tree(it->down[i]->cache_tree);
637         return err;
638 }
639
640 static char const * const fsck_usage[] = {
641         N_("git fsck [<options>] [<object>...]"),
642         NULL
643 };
644
645 static struct option fsck_opts[] = {
646         OPT__VERBOSE(&verbose, N_("be verbose")),
647         OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
648         OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
649         OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
650         OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
651         OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
652         OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
653         OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
654         OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
655         OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
656         OPT_BOOL(0, "lost-found", &write_lost_and_found,
657                                 N_("write dangling objects in .git/lost-found")),
658         OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
659         OPT_END(),
660 };
661
662 int cmd_fsck(int argc, const char **argv, const char *prefix)
663 {
664         int i, heads;
665         struct alternate_object_database *alt;
666
667         errors_found = 0;
668         check_replace_refs = 0;
669
670         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
671
672         fsck_walk_options.walk = mark_object;
673         fsck_obj_options.walk = mark_used;
674         fsck_obj_options.error_func = fsck_error_func;
675         if (check_strict)
676                 fsck_obj_options.strict = 1;
677
678         if (show_progress == -1)
679                 show_progress = isatty(2);
680         if (verbose)
681                 show_progress = 0;
682
683         if (write_lost_and_found) {
684                 check_full = 1;
685                 include_reflogs = 0;
686         }
687
688         git_config(fsck_config, NULL);
689
690         fsck_head_link();
691         if (!connectivity_only)
692                 fsck_object_dir(get_object_directory());
693
694         prepare_alt_odb();
695         for (alt = alt_odb_list; alt; alt = alt->next) {
696                 char namebuf[PATH_MAX];
697                 int namelen = alt->name - alt->base;
698                 memcpy(namebuf, alt->base, namelen);
699                 namebuf[namelen - 1] = 0;
700                 fsck_object_dir(namebuf);
701         }
702
703         if (check_full) {
704                 struct packed_git *p;
705                 uint32_t total = 0, count = 0;
706                 struct progress *progress = NULL;
707
708                 prepare_packed_git();
709
710                 if (show_progress) {
711                         for (p = packed_git; p; p = p->next) {
712                                 if (open_pack_index(p))
713                                         continue;
714                                 total += p->num_objects;
715                         }
716
717                         progress = start_progress(_("Checking objects"), total);
718                 }
719                 for (p = packed_git; p; p = p->next) {
720                         /* verify gives error messages itself */
721                         if (verify_pack(p, fsck_obj_buffer,
722                                         progress, count))
723                                 errors_found |= ERROR_PACK;
724                         count += p->num_objects;
725                 }
726                 stop_progress(&progress);
727         }
728
729         heads = 0;
730         for (i = 0; i < argc; i++) {
731                 const char *arg = argv[i];
732                 unsigned char sha1[20];
733                 if (!get_sha1(arg, sha1)) {
734                         struct object *obj = lookup_object(sha1);
735
736                         /* Error is printed by lookup_object(). */
737                         if (!obj)
738                                 continue;
739
740                         obj->used = 1;
741                         mark_object_reachable(obj);
742                         heads++;
743                         continue;
744                 }
745                 error("invalid parameter: expected sha1, got '%s'", arg);
746         }
747
748         /*
749          * If we've not been given any explicit head information, do the
750          * default ones from .git/refs. We also consider the index file
751          * in this case (ie this implies --cache).
752          */
753         if (!heads) {
754                 get_default_heads();
755                 keep_cache_objects = 1;
756         }
757
758         if (keep_cache_objects) {
759                 read_cache();
760                 for (i = 0; i < active_nr; i++) {
761                         unsigned int mode;
762                         struct blob *blob;
763                         struct object *obj;
764
765                         mode = active_cache[i]->ce_mode;
766                         if (S_ISGITLINK(mode))
767                                 continue;
768                         blob = lookup_blob(active_cache[i]->sha1);
769                         if (!blob)
770                                 continue;
771                         obj = &blob->object;
772                         obj->used = 1;
773                         mark_object_reachable(obj);
774                 }
775                 if (active_cache_tree)
776                         fsck_cache_tree(active_cache_tree);
777         }
778
779         check_connectivity();
780         return errors_found;
781 }