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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [super.c] - Blame information for rev 62

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1 62 marcus.erl
/*
2
 *  linux/fs/super.c
3
 *
4
 *  Copyright (C) 1991, 1992  Linus Torvalds
5
 *
6
 *  super.c contains code to handle: - mount structures
7
 *                                   - super-block tables
8
 *                                   - filesystem drivers list
9
 *                                   - mount system call
10
 *                                   - umount system call
11
 *                                   - ustat system call
12
 *
13
 * GK 2/5/95  -  Changed to support mounting the root fs via NFS
14
 *
15
 *  Added kerneld support: Jacques Gelinas and Bjorn Ekwall
16
 *  Added change_root: Werner Almesberger & Hans Lermen, Feb '96
17
 *  Added options to /proc/mounts:
18
 *    Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
19
 *  Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998
20
 *  Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
21
 */
22
 
23
#include <linux/module.h>
24
#include <linux/slab.h>
25
#include <linux/init.h>
26
#include <linux/smp_lock.h>
27
#include <linux/acct.h>
28
#include <linux/blkdev.h>
29
#include <linux/quotaops.h>
30
#include <linux/namei.h>
31
#include <linux/buffer_head.h>          /* for fsync_super() */
32
#include <linux/mount.h>
33
#include <linux/security.h>
34
#include <linux/syscalls.h>
35
#include <linux/vfs.h>
36
#include <linux/writeback.h>            /* for the emergency remount stuff */
37
#include <linux/idr.h>
38
#include <linux/kobject.h>
39
#include <linux/mutex.h>
40
#include <asm/uaccess.h>
41
 
42
 
43
LIST_HEAD(super_blocks);
44
DEFINE_SPINLOCK(sb_lock);
45
 
46
/**
47
 *      alloc_super     -       create new superblock
48
 *      @type:  filesystem type superblock should belong to
49
 *
50
 *      Allocates and initializes a new &struct super_block.  alloc_super()
51
 *      returns a pointer new superblock or %NULL if allocation had failed.
52
 */
53
static struct super_block *alloc_super(struct file_system_type *type)
54
{
55
        struct super_block *s = kzalloc(sizeof(struct super_block),  GFP_USER);
56
        static struct super_operations default_op;
57
 
58
        if (s) {
59
                if (security_sb_alloc(s)) {
60
                        kfree(s);
61
                        s = NULL;
62
                        goto out;
63
                }
64
                INIT_LIST_HEAD(&s->s_dirty);
65
                INIT_LIST_HEAD(&s->s_io);
66
                INIT_LIST_HEAD(&s->s_more_io);
67
                INIT_LIST_HEAD(&s->s_files);
68
                INIT_LIST_HEAD(&s->s_instances);
69
                INIT_HLIST_HEAD(&s->s_anon);
70
                INIT_LIST_HEAD(&s->s_inodes);
71
                init_rwsem(&s->s_umount);
72
                mutex_init(&s->s_lock);
73
                lockdep_set_class(&s->s_umount, &type->s_umount_key);
74
                /*
75
                 * The locking rules for s_lock are up to the
76
                 * filesystem. For example ext3fs has different
77
                 * lock ordering than usbfs:
78
                 */
79
                lockdep_set_class(&s->s_lock, &type->s_lock_key);
80
                down_write(&s->s_umount);
81
                s->s_count = S_BIAS;
82
                atomic_set(&s->s_active, 1);
83
                mutex_init(&s->s_vfs_rename_mutex);
84
                mutex_init(&s->s_dquot.dqio_mutex);
85
                mutex_init(&s->s_dquot.dqonoff_mutex);
86
                init_rwsem(&s->s_dquot.dqptr_sem);
87
                init_waitqueue_head(&s->s_wait_unfrozen);
88
                s->s_maxbytes = MAX_NON_LFS;
89
                s->dq_op = sb_dquot_ops;
90
                s->s_qcop = sb_quotactl_ops;
91
                s->s_op = &default_op;
92
                s->s_time_gran = 1000000000;
93
        }
94
out:
95
        return s;
96
}
97
 
98
/**
99
 *      destroy_super   -       frees a superblock
100
 *      @s: superblock to free
101
 *
102
 *      Frees a superblock.
103
 */
104
static inline void destroy_super(struct super_block *s)
105
{
106
        security_sb_free(s);
107
        kfree(s->s_subtype);
108
        kfree(s);
109
}
110
 
111
/* Superblock refcounting  */
112
 
113
/*
114
 * Drop a superblock's refcount.  Returns non-zero if the superblock was
115
 * destroyed.  The caller must hold sb_lock.
116
 */
117
int __put_super(struct super_block *sb)
118
{
119
        int ret = 0;
120
 
121
        if (!--sb->s_count) {
122
                destroy_super(sb);
123
                ret = 1;
124
        }
125
        return ret;
126
}
127
 
128
/*
129
 * Drop a superblock's refcount.
130
 * Returns non-zero if the superblock is about to be destroyed and
131
 * at least is already removed from super_blocks list, so if we are
132
 * making a loop through super blocks then we need to restart.
133
 * The caller must hold sb_lock.
134
 */
135
int __put_super_and_need_restart(struct super_block *sb)
136
{
137
        /* check for race with generic_shutdown_super() */
138
        if (list_empty(&sb->s_list)) {
139
                /* super block is removed, need to restart... */
140
                __put_super(sb);
141
                return 1;
142
        }
143
        /* can't be the last, since s_list is still in use */
144
        sb->s_count--;
145
        BUG_ON(sb->s_count == 0);
146
        return 0;
147
}
148
 
149
/**
150
 *      put_super       -       drop a temporary reference to superblock
151
 *      @sb: superblock in question
152
 *
153
 *      Drops a temporary reference, frees superblock if there's no
154
 *      references left.
155
 */
156
static void 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
 *      deactivate_super        -       drop an active reference to superblock
166
 *      @s: superblock to deactivate
167
 *
168
 *      Drops an active reference to superblock, acquiring a temprory one if
169
 *      there is no active references left.  In that case we lock superblock,
170
 *      tell fs driver to shut it down and drop the temporary reference we
171
 *      had just acquired.
172
 */
173
void deactivate_super(struct super_block *s)
174
{
175
        struct file_system_type *fs = s->s_type;
176
        if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
177
                s->s_count -= S_BIAS-1;
178
                spin_unlock(&sb_lock);
179
                DQUOT_OFF(s);
180
                down_write(&s->s_umount);
181
                fs->kill_sb(s);
182
                put_filesystem(fs);
183
                put_super(s);
184
        }
185
}
186
 
187
EXPORT_SYMBOL(deactivate_super);
188
 
189
/**
190
 *      grab_super - acquire an active reference
191
 *      @s: reference we are trying to make active
192
 *
193
 *      Tries to acquire an active reference.  grab_super() is used when we
194
 *      had just found a superblock in super_blocks or fs_type->fs_supers
195
 *      and want to turn it into a full-blown active reference.  grab_super()
196
 *      is called with sb_lock held and drops it.  Returns 1 in case of
197
 *      success, 0 if we had failed (superblock contents was already dead or
198
 *      dying when grab_super() had been called).
199
 */
200
static int grab_super(struct super_block *s) __releases(sb_lock)
201
{
202
        s->s_count++;
203
        spin_unlock(&sb_lock);
204
        down_write(&s->s_umount);
205
        if (s->s_root) {
206
                spin_lock(&sb_lock);
207
                if (s->s_count > S_BIAS) {
208
                        atomic_inc(&s->s_active);
209
                        s->s_count--;
210
                        spin_unlock(&sb_lock);
211
                        return 1;
212
                }
213
                spin_unlock(&sb_lock);
214
        }
215
        up_write(&s->s_umount);
216
        put_super(s);
217
        yield();
218
        return 0;
219
}
220
 
221
/*
222
 * Superblock locking.  We really ought to get rid of these two.
223
 */
224
void lock_super(struct super_block * sb)
225
{
226
        get_fs_excl();
227
        mutex_lock(&sb->s_lock);
228
}
229
 
230
void unlock_super(struct super_block * sb)
231
{
232
        put_fs_excl();
233
        mutex_unlock(&sb->s_lock);
234
}
235
 
236
EXPORT_SYMBOL(lock_super);
237
EXPORT_SYMBOL(unlock_super);
238
 
239
/*
240
 * Write out and wait upon all dirty data associated with this
241
 * superblock.  Filesystem data as well as the underlying block
242
 * device.  Takes the superblock lock.  Requires a second blkdev
243
 * flush by the caller to complete the operation.
244
 */
245
void __fsync_super(struct super_block *sb)
246
{
247
        sync_inodes_sb(sb, 0);
248
        DQUOT_SYNC(sb);
249
        lock_super(sb);
250
        if (sb->s_dirt && sb->s_op->write_super)
251
                sb->s_op->write_super(sb);
252
        unlock_super(sb);
253
        if (sb->s_op->sync_fs)
254
                sb->s_op->sync_fs(sb, 1);
255
        sync_blockdev(sb->s_bdev);
256
        sync_inodes_sb(sb, 1);
257
}
258
 
259
/*
260
 * Write out and wait upon all dirty data associated with this
261
 * superblock.  Filesystem data as well as the underlying block
262
 * device.  Takes the superblock lock.
263
 */
264
int fsync_super(struct super_block *sb)
265
{
266
        __fsync_super(sb);
267
        return sync_blockdev(sb->s_bdev);
268
}
269
 
270
/**
271
 *      generic_shutdown_super  -       common helper for ->kill_sb()
272
 *      @sb: superblock to kill
273
 *
274
 *      generic_shutdown_super() does all fs-independent work on superblock
275
 *      shutdown.  Typical ->kill_sb() should pick all fs-specific objects
276
 *      that need destruction out of superblock, call generic_shutdown_super()
277
 *      and release aforementioned objects.  Note: dentries and inodes _are_
278
 *      taken care of and do not need specific handling.
279
 *
280
 *      Upon calling this function, the filesystem may no longer alter or
281
 *      rearrange the set of dentries belonging to this super_block, nor may it
282
 *      change the attachments of dentries to inodes.
283
 */
284
void generic_shutdown_super(struct super_block *sb)
285
{
286
        const struct super_operations *sop = sb->s_op;
287
 
288
        if (sb->s_root) {
289
                shrink_dcache_for_umount(sb);
290
                fsync_super(sb);
291
                lock_super(sb);
292
                sb->s_flags &= ~MS_ACTIVE;
293
                /* bad name - it should be evict_inodes() */
294
                invalidate_inodes(sb);
295
                lock_kernel();
296
 
297
                if (sop->write_super && sb->s_dirt)
298
                        sop->write_super(sb);
299
                if (sop->put_super)
300
                        sop->put_super(sb);
301
 
302
                /* Forget any remaining inodes */
303
                if (invalidate_inodes(sb)) {
304
                        printk("VFS: Busy inodes after unmount of %s. "
305
                           "Self-destruct in 5 seconds.  Have a nice day...\n",
306
                           sb->s_id);
307
                }
308
 
309
                unlock_kernel();
310
                unlock_super(sb);
311
        }
312
        spin_lock(&sb_lock);
313
        /* should be initialized for __put_super_and_need_restart() */
314
        list_del_init(&sb->s_list);
315
        list_del(&sb->s_instances);
316
        spin_unlock(&sb_lock);
317
        up_write(&sb->s_umount);
318
}
319
 
320
EXPORT_SYMBOL(generic_shutdown_super);
321
 
322
/**
323
 *      sget    -       find or create a superblock
324
 *      @type:  filesystem type superblock should belong to
325
 *      @test:  comparison callback
326
 *      @set:   setup callback
327
 *      @data:  argument to each of them
328
 */
329
struct super_block *sget(struct file_system_type *type,
330
                        int (*test)(struct super_block *,void *),
331
                        int (*set)(struct super_block *,void *),
332
                        void *data)
333
{
334
        struct super_block *s = NULL;
335
        struct super_block *old;
336
        int err;
337
 
338
retry:
339
        spin_lock(&sb_lock);
340
        if (test) {
341
                list_for_each_entry(old, &type->fs_supers, s_instances) {
342
                        if (!test(old, data))
343
                                continue;
344
                        if (!grab_super(old))
345
                                goto retry;
346
                        if (s)
347
                                destroy_super(s);
348
                        return old;
349
                }
350
        }
351
        if (!s) {
352
                spin_unlock(&sb_lock);
353
                s = alloc_super(type);
354
                if (!s)
355
                        return ERR_PTR(-ENOMEM);
356
                goto retry;
357
        }
358
 
359
        err = set(s, data);
360
        if (err) {
361
                spin_unlock(&sb_lock);
362
                destroy_super(s);
363
                return ERR_PTR(err);
364
        }
365
        s->s_type = type;
366
        strlcpy(s->s_id, type->name, sizeof(s->s_id));
367
        list_add_tail(&s->s_list, &super_blocks);
368
        list_add(&s->s_instances, &type->fs_supers);
369
        spin_unlock(&sb_lock);
370
        get_filesystem(type);
371
        return s;
372
}
373
 
374
EXPORT_SYMBOL(sget);
375
 
376
void drop_super(struct super_block *sb)
377
{
378
        up_read(&sb->s_umount);
379
        put_super(sb);
380
}
381
 
382
EXPORT_SYMBOL(drop_super);
383
 
384
static inline void write_super(struct super_block *sb)
385
{
386
        lock_super(sb);
387
        if (sb->s_root && sb->s_dirt)
388
                if (sb->s_op->write_super)
389
                        sb->s_op->write_super(sb);
390
        unlock_super(sb);
391
}
392
 
393
/*
394
 * Note: check the dirty flag before waiting, so we don't
395
 * hold up the sync while mounting a device. (The newly
396
 * mounted device won't need syncing.)
397
 */
398
void sync_supers(void)
399
{
400
        struct super_block *sb;
401
 
402
        spin_lock(&sb_lock);
403
restart:
404
        list_for_each_entry(sb, &super_blocks, s_list) {
405
                if (sb->s_dirt) {
406
                        sb->s_count++;
407
                        spin_unlock(&sb_lock);
408
                        down_read(&sb->s_umount);
409
                        write_super(sb);
410
                        up_read(&sb->s_umount);
411
                        spin_lock(&sb_lock);
412
                        if (__put_super_and_need_restart(sb))
413
                                goto restart;
414
                }
415
        }
416
        spin_unlock(&sb_lock);
417
}
418
 
419
/*
420
 * Call the ->sync_fs super_op against all filesystems which are r/w and
421
 * which implement it.
422
 *
423
 * This operation is careful to avoid the livelock which could easily happen
424
 * if two or more filesystems are being continuously dirtied.  s_need_sync_fs
425
 * is used only here.  We set it against all filesystems and then clear it as
426
 * we sync them.  So redirtied filesystems are skipped.
427
 *
428
 * But if process A is currently running sync_filesystems and then process B
429
 * calls sync_filesystems as well, process B will set all the s_need_sync_fs
430
 * flags again, which will cause process A to resync everything.  Fix that with
431
 * a local mutex.
432
 *
433
 * (Fabian) Avoid sync_fs with clean fs & wait mode 0
434
 */
435
void sync_filesystems(int wait)
436
{
437
        struct super_block *sb;
438
        static DEFINE_MUTEX(mutex);
439
 
440
        mutex_lock(&mutex);             /* Could be down_interruptible */
441
        spin_lock(&sb_lock);
442
        list_for_each_entry(sb, &super_blocks, s_list) {
443
                if (!sb->s_op->sync_fs)
444
                        continue;
445
                if (sb->s_flags & MS_RDONLY)
446
                        continue;
447
                sb->s_need_sync_fs = 1;
448
        }
449
 
450
restart:
451
        list_for_each_entry(sb, &super_blocks, s_list) {
452
                if (!sb->s_need_sync_fs)
453
                        continue;
454
                sb->s_need_sync_fs = 0;
455
                if (sb->s_flags & MS_RDONLY)
456
                        continue;       /* hm.  Was remounted r/o meanwhile */
457
                sb->s_count++;
458
                spin_unlock(&sb_lock);
459
                down_read(&sb->s_umount);
460
                if (sb->s_root && (wait || sb->s_dirt))
461
                        sb->s_op->sync_fs(sb, wait);
462
                up_read(&sb->s_umount);
463
                /* restart only when sb is no longer on the list */
464
                spin_lock(&sb_lock);
465
                if (__put_super_and_need_restart(sb))
466
                        goto restart;
467
        }
468
        spin_unlock(&sb_lock);
469
        mutex_unlock(&mutex);
470
}
471
 
472
/**
473
 *      get_super - get the superblock of a device
474
 *      @bdev: device to get the superblock for
475
 *
476
 *      Scans the superblock list and finds the superblock of the file system
477
 *      mounted on the device given. %NULL is returned if no match is found.
478
 */
479
 
480
struct super_block * get_super(struct block_device *bdev)
481
{
482
        struct super_block *sb;
483
 
484
        if (!bdev)
485
                return NULL;
486
 
487
        spin_lock(&sb_lock);
488
rescan:
489
        list_for_each_entry(sb, &super_blocks, s_list) {
490
                if (sb->s_bdev == bdev) {
491
                        sb->s_count++;
492
                        spin_unlock(&sb_lock);
493
                        down_read(&sb->s_umount);
494
                        if (sb->s_root)
495
                                return sb;
496
                        up_read(&sb->s_umount);
497
                        /* restart only when sb is no longer on the list */
498
                        spin_lock(&sb_lock);
499
                        if (__put_super_and_need_restart(sb))
500
                                goto rescan;
501
                }
502
        }
503
        spin_unlock(&sb_lock);
504
        return NULL;
505
}
506
 
507
EXPORT_SYMBOL(get_super);
508
 
509
struct super_block * user_get_super(dev_t dev)
510
{
511
        struct super_block *sb;
512
 
513
        spin_lock(&sb_lock);
514
rescan:
515
        list_for_each_entry(sb, &super_blocks, s_list) {
516
                if (sb->s_dev ==  dev) {
517
                        sb->s_count++;
518
                        spin_unlock(&sb_lock);
519
                        down_read(&sb->s_umount);
520
                        if (sb->s_root)
521
                                return sb;
522
                        up_read(&sb->s_umount);
523
                        /* restart only when sb is no longer on the list */
524
                        spin_lock(&sb_lock);
525
                        if (__put_super_and_need_restart(sb))
526
                                goto rescan;
527
                }
528
        }
529
        spin_unlock(&sb_lock);
530
        return NULL;
531
}
532
 
533
asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf)
534
{
535
        struct super_block *s;
536
        struct ustat tmp;
537
        struct kstatfs sbuf;
538
        int err = -EINVAL;
539
 
540
        s = user_get_super(new_decode_dev(dev));
541
        if (s == NULL)
542
                goto out;
543
        err = vfs_statfs(s->s_root, &sbuf);
544
        drop_super(s);
545
        if (err)
546
                goto out;
547
 
548
        memset(&tmp,0,sizeof(struct ustat));
549
        tmp.f_tfree = sbuf.f_bfree;
550
        tmp.f_tinode = sbuf.f_ffree;
551
 
552
        err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
553
out:
554
        return err;
555
}
556
 
557
/**
558
 *      mark_files_ro
559
 *      @sb: superblock in question
560
 *
561
 *      All files are marked read/only.  We don't care about pending
562
 *      delete files so this should be used in 'force' mode only
563
 */
564
 
565
static void mark_files_ro(struct super_block *sb)
566
{
567
        struct file *f;
568
 
569
        file_list_lock();
570
        list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
571
                if (S_ISREG(f->f_path.dentry->d_inode->i_mode) && file_count(f))
572
                        f->f_mode &= ~FMODE_WRITE;
573
        }
574
        file_list_unlock();
575
}
576
 
577
/**
578
 *      do_remount_sb - asks filesystem to change mount options.
579
 *      @sb:    superblock in question
580
 *      @flags: numeric part of options
581
 *      @data:  the rest of options
582
 *      @force: whether or not to force the change
583
 *
584
 *      Alters the mount options of a mounted file system.
585
 */
586
int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
587
{
588
        int retval;
589
 
590
#ifdef CONFIG_BLOCK
591
        if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
592
                return -EACCES;
593
#endif
594
        if (flags & MS_RDONLY)
595
                acct_auto_close(sb);
596
        shrink_dcache_sb(sb);
597
        fsync_super(sb);
598
 
599
        /* If we are remounting RDONLY and current sb is read/write,
600
           make sure there are no rw files opened */
601
        if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
602
                if (force)
603
                        mark_files_ro(sb);
604
                else if (!fs_may_remount_ro(sb))
605
                        return -EBUSY;
606
        }
607
 
608
        if (sb->s_op->remount_fs) {
609
                lock_super(sb);
610
                retval = sb->s_op->remount_fs(sb, &flags, data);
611
                unlock_super(sb);
612
                if (retval)
613
                        return retval;
614
        }
615
        sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
616
        return 0;
617
}
618
 
619
static void do_emergency_remount(unsigned long foo)
620
{
621
        struct super_block *sb;
622
 
623
        spin_lock(&sb_lock);
624
        list_for_each_entry(sb, &super_blocks, s_list) {
625
                sb->s_count++;
626
                spin_unlock(&sb_lock);
627
                down_read(&sb->s_umount);
628
                if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
629
                        /*
630
                         * ->remount_fs needs lock_kernel().
631
                         *
632
                         * What lock protects sb->s_flags??
633
                         */
634
                        lock_kernel();
635
                        do_remount_sb(sb, MS_RDONLY, NULL, 1);
636
                        unlock_kernel();
637
                }
638
                drop_super(sb);
639
                spin_lock(&sb_lock);
640
        }
641
        spin_unlock(&sb_lock);
642
        printk("Emergency Remount complete\n");
643
}
644
 
645
void emergency_remount(void)
646
{
647
        pdflush_operation(do_emergency_remount, 0);
648
}
649
 
650
/*
651
 * Unnamed block devices are dummy devices used by virtual
652
 * filesystems which don't use real block-devices.  -- jrs
653
 */
654
 
655
static struct idr unnamed_dev_idr;
656
static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
657
 
658
int set_anon_super(struct super_block *s, void *data)
659
{
660
        int dev;
661
        int error;
662
 
663
 retry:
664
        if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0)
665
                return -ENOMEM;
666
        spin_lock(&unnamed_dev_lock);
667
        error = idr_get_new(&unnamed_dev_idr, NULL, &dev);
668
        spin_unlock(&unnamed_dev_lock);
669
        if (error == -EAGAIN)
670
                /* We raced and lost with another CPU. */
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
                idr_remove(&unnamed_dev_idr, dev);
678
                spin_unlock(&unnamed_dev_lock);
679
                return -EMFILE;
680
        }
681
        s->s_dev = MKDEV(0, dev & MINORMASK);
682
        return 0;
683
}
684
 
685
EXPORT_SYMBOL(set_anon_super);
686
 
687
void kill_anon_super(struct super_block *sb)
688
{
689
        int slot = MINOR(sb->s_dev);
690
 
691
        generic_shutdown_super(sb);
692
        spin_lock(&unnamed_dev_lock);
693
        idr_remove(&unnamed_dev_idr, slot);
694
        spin_unlock(&unnamed_dev_lock);
695
}
696
 
697
EXPORT_SYMBOL(kill_anon_super);
698
 
699
void __init unnamed_dev_init(void)
700
{
701
        idr_init(&unnamed_dev_idr);
702
}
703
 
704
void 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
 
711
EXPORT_SYMBOL(kill_litter_super);
712
 
713
#ifdef CONFIG_BLOCK
714
static int set_bdev_super(struct super_block *s, void *data)
715
{
716
        s->s_bdev = data;
717
        s->s_dev = s->s_bdev->bd_dev;
718
        return 0;
719
}
720
 
721
static int test_bdev_super(struct super_block *s, void *data)
722
{
723
        return (void *)s->s_bdev == data;
724
}
725
 
726
int get_sb_bdev(struct file_system_type *fs_type,
727
        int flags, const char *dev_name, void *data,
728
        int (*fill_super)(struct super_block *, void *, int),
729
        struct vfsmount *mnt)
730
{
731
        struct block_device *bdev;
732
        struct super_block *s;
733
        int error = 0;
734
 
735
        bdev = open_bdev_excl(dev_name, flags, fs_type);
736
        if (IS_ERR(bdev))
737
                return PTR_ERR(bdev);
738
 
739
        /*
740
         * once the super is inserted into the list by sget, s_umount
741
         * will protect the lockfs code from trying to start a snapshot
742
         * while we are mounting
743
         */
744
        down(&bdev->bd_mount_sem);
745
        s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
746
        up(&bdev->bd_mount_sem);
747
        if (IS_ERR(s))
748
                goto error_s;
749
 
750
        if (s->s_root) {
751
                if ((flags ^ s->s_flags) & MS_RDONLY) {
752
                        up_write(&s->s_umount);
753
                        deactivate_super(s);
754
                        error = -EBUSY;
755
                        goto error_bdev;
756
                }
757
 
758
                close_bdev_excl(bdev);
759
        } else {
760
                char b[BDEVNAME_SIZE];
761
 
762
                s->s_flags = flags;
763
                strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
764
                sb_set_blocksize(s, block_size(bdev));
765
                error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
766
                if (error) {
767
                        up_write(&s->s_umount);
768
                        deactivate_super(s);
769
                        goto error;
770
                }
771
 
772
                s->s_flags |= MS_ACTIVE;
773
        }
774
 
775
        return simple_set_mnt(mnt, s);
776
 
777
error_s:
778
        error = PTR_ERR(s);
779
error_bdev:
780
        close_bdev_excl(bdev);
781
error:
782
        return error;
783
}
784
 
785
EXPORT_SYMBOL(get_sb_bdev);
786
 
787
void kill_block_super(struct super_block *sb)
788
{
789
        struct block_device *bdev = sb->s_bdev;
790
 
791
        generic_shutdown_super(sb);
792
        sync_blockdev(bdev);
793
        close_bdev_excl(bdev);
794
}
795
 
796
EXPORT_SYMBOL(kill_block_super);
797
#endif
798
 
799
int get_sb_nodev(struct file_system_type *fs_type,
800
        int flags, void *data,
801
        int (*fill_super)(struct super_block *, void *, int),
802
        struct vfsmount *mnt)
803
{
804
        int error;
805
        struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
806
 
807
        if (IS_ERR(s))
808
                return PTR_ERR(s);
809
 
810
        s->s_flags = flags;
811
 
812
        error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
813
        if (error) {
814
                up_write(&s->s_umount);
815
                deactivate_super(s);
816
                return error;
817
        }
818
        s->s_flags |= MS_ACTIVE;
819
        return simple_set_mnt(mnt, s);
820
}
821
 
822
EXPORT_SYMBOL(get_sb_nodev);
823
 
824
static int compare_single(struct super_block *s, void *p)
825
{
826
        return 1;
827
}
828
 
829
int get_sb_single(struct file_system_type *fs_type,
830
        int flags, void *data,
831
        int (*fill_super)(struct super_block *, void *, int),
832
        struct vfsmount *mnt)
833
{
834
        struct super_block *s;
835
        int error;
836
 
837
        s = sget(fs_type, compare_single, set_anon_super, NULL);
838
        if (IS_ERR(s))
839
                return PTR_ERR(s);
840
        if (!s->s_root) {
841
                s->s_flags = flags;
842
                error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
843
                if (error) {
844
                        up_write(&s->s_umount);
845
                        deactivate_super(s);
846
                        return error;
847
                }
848
                s->s_flags |= MS_ACTIVE;
849
        }
850
        do_remount_sb(s, flags, data, 0);
851
        return simple_set_mnt(mnt, s);
852
}
853
 
854
EXPORT_SYMBOL(get_sb_single);
855
 
856
struct vfsmount *
857
vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
858
{
859
        struct vfsmount *mnt;
860
        char *secdata = NULL;
861
        int error;
862
 
863
        if (!type)
864
                return ERR_PTR(-ENODEV);
865
 
866
        error = -ENOMEM;
867
        mnt = alloc_vfsmnt(name);
868
        if (!mnt)
869
                goto out;
870
 
871
        if (data) {
872
                secdata = alloc_secdata();
873
                if (!secdata)
874
                        goto out_mnt;
875
 
876
                error = security_sb_copy_data(type, data, secdata);
877
                if (error)
878
                        goto out_free_secdata;
879
        }
880
 
881
        error = type->get_sb(type, flags, name, data, mnt);
882
        if (error < 0)
883
                goto out_free_secdata;
884
        BUG_ON(!mnt->mnt_sb);
885
 
886
        error = security_sb_kern_mount(mnt->mnt_sb, secdata);
887
        if (error)
888
                goto out_sb;
889
 
890
        mnt->mnt_mountpoint = mnt->mnt_root;
891
        mnt->mnt_parent = mnt;
892
        up_write(&mnt->mnt_sb->s_umount);
893
        free_secdata(secdata);
894
        return mnt;
895
out_sb:
896
        dput(mnt->mnt_root);
897
        up_write(&mnt->mnt_sb->s_umount);
898
        deactivate_super(mnt->mnt_sb);
899
out_free_secdata:
900
        free_secdata(secdata);
901
out_mnt:
902
        free_vfsmnt(mnt);
903
out:
904
        return ERR_PTR(error);
905
}
906
 
907
EXPORT_SYMBOL_GPL(vfs_kern_mount);
908
 
909
static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
910
{
911
        int err;
912
        const char *subtype = strchr(fstype, '.');
913
        if (subtype) {
914
                subtype++;
915
                err = -EINVAL;
916
                if (!subtype[0])
917
                        goto err;
918
        } else
919
                subtype = "";
920
 
921
        mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
922
        err = -ENOMEM;
923
        if (!mnt->mnt_sb->s_subtype)
924
                goto err;
925
        return mnt;
926
 
927
 err:
928
        mntput(mnt);
929
        return ERR_PTR(err);
930
}
931
 
932
struct vfsmount *
933
do_kern_mount(const char *fstype, int flags, const char *name, void *data)
934
{
935
        struct file_system_type *type = get_fs_type(fstype);
936
        struct vfsmount *mnt;
937
        if (!type)
938
                return ERR_PTR(-ENODEV);
939
        mnt = vfs_kern_mount(type, flags, name, data);
940
        if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
941
            !mnt->mnt_sb->s_subtype)
942
                mnt = fs_set_subtype(mnt, fstype);
943
        put_filesystem(type);
944
        return mnt;
945
}
946
 
947
struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
948
{
949
        return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
950
}
951
 
952
EXPORT_SYMBOL_GPL(kern_mount_data);

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