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23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/acct.h>
26#include <linux/blkdev.h>
27#include <linux/mount.h>
28#include <linux/security.h>
29#include <linux/writeback.h>
30#include <linux/idr.h>
31#include <linux/mutex.h>
32#include <linux/backing-dev.h>
33#include <linux/rculist_bl.h>
34#include "internal.h"
35
36
37LIST_HEAD(super_blocks);
38DEFINE_SPINLOCK(sb_lock);
39
40
41
42
43
44
45
46
47static struct super_block *alloc_super(struct file_system_type *type)
48{
49 struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
50 static const struct super_operations default_op;
51
52 if (s) {
53 if (security_sb_alloc(s)) {
54 kfree(s);
55 s = NULL;
56 goto out;
57 }
58#ifdef CONFIG_SMP
59 s->s_files = alloc_percpu(struct list_head);
60 if (!s->s_files) {
61 security_sb_free(s);
62 kfree(s);
63 s = NULL;
64 goto out;
65 } else {
66 int i;
67
68 for_each_possible_cpu(i)
69 INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i));
70 }
71#else
72 INIT_LIST_HEAD(&s->s_files);
73#endif
74 INIT_LIST_HEAD(&s->s_instances);
75 INIT_HLIST_BL_HEAD(&s->s_anon);
76 INIT_LIST_HEAD(&s->s_inodes);
77 INIT_LIST_HEAD(&s->s_dentry_lru);
78 init_rwsem(&s->s_umount);
79 mutex_init(&s->s_lock);
80 lockdep_set_class(&s->s_umount, &type->s_umount_key);
81
82
83
84
85
86 lockdep_set_class(&s->s_lock, &type->s_lock_key);
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102 down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
103 s->s_count = 1;
104 atomic_set(&s->s_active, 1);
105 mutex_init(&s->s_vfs_rename_mutex);
106 lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
107 mutex_init(&s->s_dquot.dqio_mutex);
108 mutex_init(&s->s_dquot.dqonoff_mutex);
109 init_rwsem(&s->s_dquot.dqptr_sem);
110 init_waitqueue_head(&s->s_wait_unfrozen);
111 s->s_maxbytes = MAX_NON_LFS;
112 s->s_op = &default_op;
113 s->s_time_gran = 1000000000;
114 }
115out:
116 return s;
117}
118
119
120
121
122
123
124
125static inline void destroy_super(struct super_block *s)
126{
127#ifdef CONFIG_SMP
128 free_percpu(s->s_files);
129#endif
130 security_sb_free(s);
131 kfree(s->s_subtype);
132 kfree(s->s_options);
133 kfree(s);
134}
135
136
137
138
139
140
141void __put_super(struct super_block *sb)
142{
143 if (!--sb->s_count) {
144 list_del_init(&sb->s_list);
145 destroy_super(sb);
146 }
147}
148
149
150
151
152
153
154
155
156void put_super(struct super_block *sb)
157{
158 spin_lock(&sb_lock);
159 __put_super(sb);
160 spin_unlock(&sb_lock);
161}
162
163
164
165
166
167
168
169
170
171
172
173
174
175void deactivate_locked_super(struct super_block *s)
176{
177 struct file_system_type *fs = s->s_type;
178 if (atomic_dec_and_test(&s->s_active)) {
179 fs->kill_sb(s);
180
181
182
183
184 rcu_barrier();
185 put_filesystem(fs);
186 put_super(s);
187 } else {
188 up_write(&s->s_umount);
189 }
190}
191
192EXPORT_SYMBOL(deactivate_locked_super);
193
194
195
196
197
198
199
200
201
202void deactivate_super(struct super_block *s)
203{
204 if (!atomic_add_unless(&s->s_active, -1, 1)) {
205 down_write(&s->s_umount);
206 deactivate_locked_super(s);
207 }
208}
209
210EXPORT_SYMBOL(deactivate_super);
211
212
213
214
215
216
217
218
219
220
221
222
223static int grab_super(struct super_block *s) __releases(sb_lock)
224{
225 if (atomic_inc_not_zero(&s->s_active)) {
226 spin_unlock(&sb_lock);
227 return 1;
228 }
229
230 s->s_count++;
231 spin_unlock(&sb_lock);
232
233 down_write(&s->s_umount);
234 up_write(&s->s_umount);
235 put_super(s);
236 return 0;
237}
238
239
240
241
242void lock_super(struct super_block * sb)
243{
244 get_fs_excl();
245 mutex_lock(&sb->s_lock);
246}
247
248void unlock_super(struct super_block * sb)
249{
250 put_fs_excl();
251 mutex_unlock(&sb->s_lock);
252}
253
254EXPORT_SYMBOL(lock_super);
255EXPORT_SYMBOL(unlock_super);
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271void generic_shutdown_super(struct super_block *sb)
272{
273 const struct super_operations *sop = sb->s_op;
274
275
276 if (sb->s_root) {
277 shrink_dcache_for_umount(sb);
278 sync_filesystem(sb);
279 get_fs_excl();
280 sb->s_flags &= ~MS_ACTIVE;
281
282 fsnotify_unmount_inodes(&sb->s_inodes);
283
284 evict_inodes(sb);
285
286 if (sop->put_super)
287 sop->put_super(sb);
288
289 if (!list_empty(&sb->s_inodes)) {
290 printk("VFS: Busy inodes after unmount of %s. "
291 "Self-destruct in 5 seconds. Have a nice day...\n",
292 sb->s_id);
293 }
294 put_fs_excl();
295 }
296 spin_lock(&sb_lock);
297
298 list_del_init(&sb->s_instances);
299 spin_unlock(&sb_lock);
300 up_write(&sb->s_umount);
301}
302
303EXPORT_SYMBOL(generic_shutdown_super);
304
305
306
307
308
309
310
311
312struct super_block *sget(struct file_system_type *type,
313 int (*test)(struct super_block *,void *),
314 int (*set)(struct super_block *,void *),
315 void *data)
316{
317 struct super_block *s = NULL;
318 struct super_block *old;
319 int err;
320
321retry:
322 spin_lock(&sb_lock);
323 if (test) {
324 list_for_each_entry(old, &type->fs_supers, s_instances) {
325 if (!test(old, data))
326 continue;
327 if (!grab_super(old))
328 goto retry;
329 if (s) {
330 up_write(&s->s_umount);
331 destroy_super(s);
332 s = NULL;
333 }
334 down_write(&old->s_umount);
335 if (unlikely(!(old->s_flags & MS_BORN))) {
336 deactivate_locked_super(old);
337 goto retry;
338 }
339 return old;
340 }
341 }
342 if (!s) {
343 spin_unlock(&sb_lock);
344 s = alloc_super(type);
345 if (!s)
346 return ERR_PTR(-ENOMEM);
347 goto retry;
348 }
349
350 err = set(s, data);
351 if (err) {
352 spin_unlock(&sb_lock);
353 up_write(&s->s_umount);
354 destroy_super(s);
355 return ERR_PTR(err);
356 }
357 s->s_type = type;
358 strlcpy(s->s_id, type->name, sizeof(s->s_id));
359 list_add_tail(&s->s_list, &super_blocks);
360 list_add(&s->s_instances, &type->fs_supers);
361 spin_unlock(&sb_lock);
362 get_filesystem(type);
363 return s;
364}
365
366EXPORT_SYMBOL(sget);
367
368void drop_super(struct super_block *sb)
369{
370 up_read(&sb->s_umount);
371 put_super(sb);
372}
373
374EXPORT_SYMBOL(drop_super);
375
376
377
378
379
380
381
382
383
384
385
386
387
388void sync_supers(void)
389{
390 struct super_block *sb, *p = NULL;
391
392 spin_lock(&sb_lock);
393 list_for_each_entry(sb, &super_blocks, s_list) {
394 if (list_empty(&sb->s_instances))
395 continue;
396 if (sb->s_op->write_super && sb->s_dirt) {
397 sb->s_count++;
398 spin_unlock(&sb_lock);
399
400 down_read(&sb->s_umount);
401 if (sb->s_root && sb->s_dirt)
402 sb->s_op->write_super(sb);
403 up_read(&sb->s_umount);
404
405 spin_lock(&sb_lock);
406 if (p)
407 __put_super(p);
408 p = sb;
409 }
410 }
411 if (p)
412 __put_super(p);
413 spin_unlock(&sb_lock);
414}
415
416
417
418
419
420
421
422
423
424void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
425{
426 struct super_block *sb, *p = NULL;
427
428 spin_lock(&sb_lock);
429 list_for_each_entry(sb, &super_blocks, s_list) {
430 if (list_empty(&sb->s_instances))
431 continue;
432 sb->s_count++;
433 spin_unlock(&sb_lock);
434
435 down_read(&sb->s_umount);
436 if (sb->s_root)
437 f(sb, arg);
438 up_read(&sb->s_umount);
439
440 spin_lock(&sb_lock);
441 if (p)
442 __put_super(p);
443 p = sb;
444 }
445 if (p)
446 __put_super(p);
447 spin_unlock(&sb_lock);
448}
449
450
451
452
453
454
455
456
457
458struct super_block *get_super(struct block_device *bdev)
459{
460 struct super_block *sb;
461
462 if (!bdev)
463 return NULL;
464
465 spin_lock(&sb_lock);
466rescan:
467 list_for_each_entry(sb, &super_blocks, s_list) {
468 if (list_empty(&sb->s_instances))
469 continue;
470 if (sb->s_bdev == bdev) {
471 sb->s_count++;
472 spin_unlock(&sb_lock);
473 down_read(&sb->s_umount);
474
475 if (sb->s_root)
476 return sb;
477 up_read(&sb->s_umount);
478
479 spin_lock(&sb_lock);
480 __put_super(sb);
481 goto rescan;
482 }
483 }
484 spin_unlock(&sb_lock);
485 return NULL;
486}
487
488EXPORT_SYMBOL(get_super);
489
490
491
492
493
494
495
496
497
498struct super_block *get_active_super(struct block_device *bdev)
499{
500 struct super_block *sb;
501
502 if (!bdev)
503 return NULL;
504
505restart:
506 spin_lock(&sb_lock);
507 list_for_each_entry(sb, &super_blocks, s_list) {
508 if (list_empty(&sb->s_instances))
509 continue;
510 if (sb->s_bdev == bdev) {
511 if (grab_super(sb))
512 return sb;
513 else
514 goto restart;
515 }
516 }
517 spin_unlock(&sb_lock);
518 return NULL;
519}
520
521struct super_block *user_get_super(dev_t dev)
522{
523 struct super_block *sb;
524
525 spin_lock(&sb_lock);
526rescan:
527 list_for_each_entry(sb, &super_blocks, s_list) {
528 if (list_empty(&sb->s_instances))
529 continue;
530 if (sb->s_dev == dev) {
531 sb->s_count++;
532 spin_unlock(&sb_lock);
533 down_read(&sb->s_umount);
534
535 if (sb->s_root)
536 return sb;
537 up_read(&sb->s_umount);
538
539 spin_lock(&sb_lock);
540 __put_super(sb);
541 goto rescan;
542 }
543 }
544 spin_unlock(&sb_lock);
545 return NULL;
546}
547
548
549
550
551
552
553
554
555
556
557int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
558{
559 int retval;
560 int remount_ro;
561
562 if (sb->s_frozen != SB_UNFROZEN)
563 return -EBUSY;
564
565#ifdef CONFIG_BLOCK
566 if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
567 return -EACCES;
568#endif
569
570 if (flags & MS_RDONLY)
571 acct_auto_close(sb);
572 shrink_dcache_sb(sb);
573 sync_filesystem(sb);
574
575 remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
576
577
578
579 if (remount_ro) {
580 if (force)
581 mark_files_ro(sb);
582 else if (!fs_may_remount_ro(sb))
583 return -EBUSY;
584 }
585
586 if (sb->s_op->remount_fs) {
587 retval = sb->s_op->remount_fs(sb, &flags, data);
588 if (retval)
589 return retval;
590 }
591 sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
592
593
594
595
596
597
598
599
600
601 if (remount_ro && sb->s_bdev)
602 invalidate_bdev(sb->s_bdev);
603 return 0;
604}
605
606static void do_emergency_remount(struct work_struct *work)
607{
608 struct super_block *sb, *p = NULL;
609
610 spin_lock(&sb_lock);
611 list_for_each_entry(sb, &super_blocks, s_list) {
612 if (list_empty(&sb->s_instances))
613 continue;
614 sb->s_count++;
615 spin_unlock(&sb_lock);
616 down_write(&sb->s_umount);
617 if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
618
619
620
621 do_remount_sb(sb, MS_RDONLY, NULL, 1);
622 }
623 up_write(&sb->s_umount);
624 spin_lock(&sb_lock);
625 if (p)
626 __put_super(p);
627 p = sb;
628 }
629 if (p)
630 __put_super(p);
631 spin_unlock(&sb_lock);
632 kfree(work);
633 printk("Emergency Remount complete\n");
634}
635
636void emergency_remount(void)
637{
638 struct work_struct *work;
639
640 work = kmalloc(sizeof(*work), GFP_ATOMIC);
641 if (work) {
642 INIT_WORK(work, do_emergency_remount);
643 schedule_work(work);
644 }
645}
646
647
648
649
650
651
652static DEFINE_IDA(unnamed_dev_ida);
653static DEFINE_SPINLOCK(unnamed_dev_lock);
654static int unnamed_dev_start = 0;
655
656int set_anon_super(struct super_block *s, void *data)
657{
658 int dev;
659 int error;
660
661 retry:
662 if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
663 return -ENOMEM;
664 spin_lock(&unnamed_dev_lock);
665 error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
666 if (!error)
667 unnamed_dev_start = dev + 1;
668 spin_unlock(&unnamed_dev_lock);
669 if (error == -EAGAIN)
670
671 goto retry;
672 else if (error)
673 return -EAGAIN;
674
675 if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
676 spin_lock(&unnamed_dev_lock);
677 ida_remove(&unnamed_dev_ida, dev);
678 if (unnamed_dev_start > dev)
679 unnamed_dev_start = dev;
680 spin_unlock(&unnamed_dev_lock);
681 return -EMFILE;
682 }
683 s->s_dev = MKDEV(0, dev & MINORMASK);
684 s->s_bdi = &noop_backing_dev_info;
685 return 0;
686}
687
688EXPORT_SYMBOL(set_anon_super);
689
690void kill_anon_super(struct super_block *sb)
691{
692 int slot = MINOR(sb->s_dev);
693
694 generic_shutdown_super(sb);
695 spin_lock(&unnamed_dev_lock);
696 ida_remove(&unnamed_dev_ida, slot);
697 if (slot < unnamed_dev_start)
698 unnamed_dev_start = slot;
699 spin_unlock(&unnamed_dev_lock);
700}
701
702EXPORT_SYMBOL(kill_anon_super);
703
704void kill_litter_super(struct super_block *sb)
705{
706 if (sb->s_root)
707 d_genocide(sb->s_root);
708 kill_anon_super(sb);
709}
710
711EXPORT_SYMBOL(kill_litter_super);
712
713static int ns_test_super(struct super_block *sb, void *data)
714{
715 return sb->s_fs_info == data;
716}
717
718static int ns_set_super(struct super_block *sb, void *data)
719{
720 sb->s_fs_info = data;
721 return set_anon_super(sb, NULL);
722}
723
724struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
725 void *data, int (*fill_super)(struct super_block *, void *, int))
726{
727 struct super_block *sb;
728
729 sb = sget(fs_type, ns_test_super, ns_set_super, data);
730 if (IS_ERR(sb))
731 return ERR_CAST(sb);
732
733 if (!sb->s_root) {
734 int err;
735 sb->s_flags = flags;
736 err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
737 if (err) {
738 deactivate_locked_super(sb);
739 return ERR_PTR(err);
740 }
741
742 sb->s_flags |= MS_ACTIVE;
743 }
744
745 return dget(sb->s_root);
746}
747
748EXPORT_SYMBOL(mount_ns);
749
750#ifdef CONFIG_BLOCK
751static int set_bdev_super(struct super_block *s, void *data)
752{
753 s->s_bdev = data;
754 s->s_dev = s->s_bdev->bd_dev;
755
756
757
758
759
760 s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
761 return 0;
762}
763
764static int test_bdev_super(struct super_block *s, void *data)
765{
766 return (void *)s->s_bdev == data;
767}
768
769struct dentry *mount_bdev(struct file_system_type *fs_type,
770 int flags, const char *dev_name, void *data,
771 int (*fill_super)(struct super_block *, void *, int))
772{
773 struct block_device *bdev;
774 struct super_block *s;
775 fmode_t mode = FMODE_READ | FMODE_EXCL;
776 int error = 0;
777
778 if (!(flags & MS_RDONLY))
779 mode |= FMODE_WRITE;
780
781 bdev = blkdev_get_by_path(dev_name, mode, fs_type);
782 if (IS_ERR(bdev))
783 return ERR_CAST(bdev);
784
785
786
787
788
789
790 mutex_lock(&bdev->bd_fsfreeze_mutex);
791 if (bdev->bd_fsfreeze_count > 0) {
792 mutex_unlock(&bdev->bd_fsfreeze_mutex);
793 error = -EBUSY;
794 goto error_bdev;
795 }
796 s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
797 mutex_unlock(&bdev->bd_fsfreeze_mutex);
798 if (IS_ERR(s))
799 goto error_s;
800
801 if (s->s_root) {
802 if ((flags ^ s->s_flags) & MS_RDONLY) {
803 deactivate_locked_super(s);
804 error = -EBUSY;
805 goto error_bdev;
806 }
807
808
809
810
811
812
813
814
815 up_write(&s->s_umount);
816 blkdev_put(bdev, mode);
817 down_write(&s->s_umount);
818 } else {
819 char b[BDEVNAME_SIZE];
820
821 s->s_flags = flags;
822 s->s_mode = mode;
823 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
824 sb_set_blocksize(s, block_size(bdev));
825 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
826 if (error) {
827 deactivate_locked_super(s);
828 goto error;
829 }
830
831 s->s_flags |= MS_ACTIVE;
832 bdev->bd_super = s;
833 }
834
835 return dget(s->s_root);
836
837error_s:
838 error = PTR_ERR(s);
839error_bdev:
840 blkdev_put(bdev, mode);
841error:
842 return ERR_PTR(error);
843}
844EXPORT_SYMBOL(mount_bdev);
845
846int get_sb_bdev(struct file_system_type *fs_type,
847 int flags, const char *dev_name, void *data,
848 int (*fill_super)(struct super_block *, void *, int),
849 struct vfsmount *mnt)
850{
851 struct dentry *root;
852
853 root = mount_bdev(fs_type, flags, dev_name, data, fill_super);
854 if (IS_ERR(root))
855 return PTR_ERR(root);
856 mnt->mnt_root = root;
857 mnt->mnt_sb = root->d_sb;
858 return 0;
859}
860
861EXPORT_SYMBOL(get_sb_bdev);
862
863void kill_block_super(struct super_block *sb)
864{
865 struct block_device *bdev = sb->s_bdev;
866 fmode_t mode = sb->s_mode;
867
868 bdev->bd_super = NULL;
869 generic_shutdown_super(sb);
870 sync_blockdev(bdev);
871 WARN_ON_ONCE(!(mode & FMODE_EXCL));
872 blkdev_put(bdev, mode | FMODE_EXCL);
873}
874
875EXPORT_SYMBOL(kill_block_super);
876#endif
877
878struct dentry *mount_nodev(struct file_system_type *fs_type,
879 int flags, void *data,
880 int (*fill_super)(struct super_block *, void *, int))
881{
882 int error;
883 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
884
885 if (IS_ERR(s))
886 return ERR_CAST(s);
887
888 s->s_flags = flags;
889
890 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
891 if (error) {
892 deactivate_locked_super(s);
893 return ERR_PTR(error);
894 }
895 s->s_flags |= MS_ACTIVE;
896 return dget(s->s_root);
897}
898EXPORT_SYMBOL(mount_nodev);
899
900int get_sb_nodev(struct file_system_type *fs_type,
901 int flags, void *data,
902 int (*fill_super)(struct super_block *, void *, int),
903 struct vfsmount *mnt)
904{
905 struct dentry *root;
906
907 root = mount_nodev(fs_type, flags, data, fill_super);
908 if (IS_ERR(root))
909 return PTR_ERR(root);
910 mnt->mnt_root = root;
911 mnt->mnt_sb = root->d_sb;
912 return 0;
913}
914EXPORT_SYMBOL(get_sb_nodev);
915
916static int compare_single(struct super_block *s, void *p)
917{
918 return 1;
919}
920
921struct dentry *mount_single(struct file_system_type *fs_type,
922 int flags, void *data,
923 int (*fill_super)(struct super_block *, void *, int))
924{
925 struct super_block *s;
926 int error;
927
928 s = sget(fs_type, compare_single, set_anon_super, NULL);
929 if (IS_ERR(s))
930 return ERR_CAST(s);
931 if (!s->s_root) {
932 s->s_flags = flags;
933 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
934 if (error) {
935 deactivate_locked_super(s);
936 return ERR_PTR(error);
937 }
938 s->s_flags |= MS_ACTIVE;
939 } else {
940 do_remount_sb(s, flags, data, 0);
941 }
942 return dget(s->s_root);
943}
944EXPORT_SYMBOL(mount_single);
945
946int get_sb_single(struct file_system_type *fs_type,
947 int flags, void *data,
948 int (*fill_super)(struct super_block *, void *, int),
949 struct vfsmount *mnt)
950{
951 struct dentry *root;
952 root = mount_single(fs_type, flags, data, fill_super);
953 if (IS_ERR(root))
954 return PTR_ERR(root);
955 mnt->mnt_root = root;
956 mnt->mnt_sb = root->d_sb;
957 return 0;
958}
959
960EXPORT_SYMBOL(get_sb_single);
961
962struct vfsmount *
963vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
964{
965 struct vfsmount *mnt;
966 struct dentry *root;
967 char *secdata = NULL;
968 int error;
969
970 if (!type)
971 return ERR_PTR(-ENODEV);
972
973 error = -ENOMEM;
974 mnt = alloc_vfsmnt(name);
975 if (!mnt)
976 goto out;
977
978 if (flags & MS_KERNMOUNT)
979 mnt->mnt_flags = MNT_INTERNAL;
980
981 if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
982 secdata = alloc_secdata();
983 if (!secdata)
984 goto out_mnt;
985
986 error = security_sb_copy_data(data, secdata);
987 if (error)
988 goto out_free_secdata;
989 }
990
991 if (type->mount) {
992 root = type->mount(type, flags, name, data);
993 if (IS_ERR(root)) {
994 error = PTR_ERR(root);
995 goto out_free_secdata;
996 }
997 mnt->mnt_root = root;
998 mnt->mnt_sb = root->d_sb;
999 } else {
1000 error = type->get_sb(type, flags, name, data, mnt);
1001 if (error < 0)
1002 goto out_free_secdata;
1003 }
1004 BUG_ON(!mnt->mnt_sb);
1005 WARN_ON(!mnt->mnt_sb->s_bdi);
1006 mnt->mnt_sb->s_flags |= MS_BORN;
1007
1008 error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
1009 if (error)
1010 goto out_sb;
1011
1012
1013
1014
1015
1016
1017
1018
1019 WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
1020 "negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);
1021
1022 mnt->mnt_mountpoint = mnt->mnt_root;
1023 mnt->mnt_parent = mnt;
1024 up_write(&mnt->mnt_sb->s_umount);
1025 free_secdata(secdata);
1026 return mnt;
1027out_sb:
1028 dput(mnt->mnt_root);
1029 deactivate_locked_super(mnt->mnt_sb);
1030out_free_secdata:
1031 free_secdata(secdata);
1032out_mnt:
1033 free_vfsmnt(mnt);
1034out:
1035 return ERR_PTR(error);
1036}
1037
1038EXPORT_SYMBOL_GPL(vfs_kern_mount);
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048int freeze_super(struct super_block *sb)
1049{
1050 int ret;
1051
1052 atomic_inc(&sb->s_active);
1053 down_write(&sb->s_umount);
1054 if (sb->s_frozen) {
1055 deactivate_locked_super(sb);
1056 return -EBUSY;
1057 }
1058
1059 if (sb->s_flags & MS_RDONLY) {
1060 sb->s_frozen = SB_FREEZE_TRANS;
1061 smp_wmb();
1062 up_write(&sb->s_umount);
1063 return 0;
1064 }
1065
1066 sb->s_frozen = SB_FREEZE_WRITE;
1067 smp_wmb();
1068
1069 sync_filesystem(sb);
1070
1071 sb->s_frozen = SB_FREEZE_TRANS;
1072 smp_wmb();
1073
1074 sync_blockdev(sb->s_bdev);
1075 if (sb->s_op->freeze_fs) {
1076 ret = sb->s_op->freeze_fs(sb);
1077 if (ret) {
1078 printk(KERN_ERR
1079 "VFS:Filesystem freeze failed\n");
1080 sb->s_frozen = SB_UNFROZEN;
1081 deactivate_locked_super(sb);
1082 return ret;
1083 }
1084 }
1085 up_write(&sb->s_umount);
1086 return 0;
1087}
1088EXPORT_SYMBOL(freeze_super);
1089
1090
1091
1092
1093
1094
1095
1096int thaw_super(struct super_block *sb)
1097{
1098 int error;
1099
1100 down_write(&sb->s_umount);
1101 if (sb->s_frozen == SB_UNFROZEN) {
1102 up_write(&sb->s_umount);
1103 return -EINVAL;
1104 }
1105
1106 if (sb->s_flags & MS_RDONLY)
1107 goto out;
1108
1109 if (sb->s_op->unfreeze_fs) {
1110 error = sb->s_op->unfreeze_fs(sb);
1111 if (error) {
1112 printk(KERN_ERR
1113 "VFS:Filesystem thaw failed\n");
1114 sb->s_frozen = SB_FREEZE_TRANS;
1115 up_write(&sb->s_umount);
1116 return error;
1117 }
1118 }
1119
1120out:
1121 sb->s_frozen = SB_UNFROZEN;
1122 smp_wmb();
1123 wake_up(&sb->s_wait_unfrozen);
1124 deactivate_locked_super(sb);
1125
1126 return 0;
1127}
1128EXPORT_SYMBOL(thaw_super);
1129
1130static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
1131{
1132 int err;
1133 const char *subtype = strchr(fstype, '.');
1134 if (subtype) {
1135 subtype++;
1136 err = -EINVAL;
1137 if (!subtype[0])
1138 goto err;
1139 } else
1140 subtype = "";
1141
1142 mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
1143 err = -ENOMEM;
1144 if (!mnt->mnt_sb->s_subtype)
1145 goto err;
1146 return mnt;
1147
1148 err:
1149 mntput(mnt);
1150 return ERR_PTR(err);
1151}
1152
1153struct vfsmount *
1154do_kern_mount(const char *fstype, int flags, const char *name, void *data)
1155{
1156 struct file_system_type *type = get_fs_type(fstype);
1157 struct vfsmount *mnt;
1158 if (!type)
1159 return ERR_PTR(-ENODEV);
1160 mnt = vfs_kern_mount(type, flags, name, data);
1161 if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
1162 !mnt->mnt_sb->s_subtype)
1163 mnt = fs_set_subtype(mnt, fstype);
1164 put_filesystem(type);
1165 return mnt;
1166}
1167EXPORT_SYMBOL_GPL(do_kern_mount);
1168
1169struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
1170{
1171 return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
1172}
1173
1174EXPORT_SYMBOL_GPL(kern_mount_data);
1175