super.c 20.6 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
/*
 *  linux/fs/super.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  super.c contains code to handle: - mount structures
 *                                   - super-block tables
 *                                   - filesystem drivers list
 *                                   - mount system call
 *                                   - umount system call
 *                                   - ustat system call
 *
 * GK 2/5/95  -  Changed to support mounting the root fs via NFS
 *
 *  Added kerneld support: Jacques Gelinas and Bjorn Ekwall
 *  Added change_root: Werner Almesberger & Hans Lermen, Feb '96
 *  Added options to /proc/mounts:
 *    Torbjrn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
 *  Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998
 *  Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/acct.h>
#include <linux/blkdev.h>
#include <linux/quotaops.h>
#include <linux/namei.h>
#include <linux/buffer_head.h>		/* for fsync_super() */
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/vfs.h>
#include <linux/writeback.h>		/* for the emergency remount stuff */
#include <linux/idr.h>
#include <linux/kobject.h>
I
Ingo Molnar 已提交
39
#include <linux/mutex.h>
L
Linus Torvalds 已提交
40 41 42 43 44 45 46 47 48 49 50 51
#include <asm/uaccess.h>


void get_filesystem(struct file_system_type *fs);
void put_filesystem(struct file_system_type *fs);
struct file_system_type *get_fs_type(const char *name);

LIST_HEAD(super_blocks);
DEFINE_SPINLOCK(sb_lock);

/**
 *	alloc_super	-	create new superblock
52
 *	@type:	filesystem type superblock should belong to
L
Linus Torvalds 已提交
53 54 55 56
 *
 *	Allocates and initializes a new &struct super_block.  alloc_super()
 *	returns a pointer new superblock or %NULL if allocation had failed.
 */
I
Ingo Molnar 已提交
57
static struct super_block *alloc_super(struct file_system_type *type)
L
Linus Torvalds 已提交
58
{
59
	struct super_block *s = kzalloc(sizeof(struct super_block),  GFP_USER);
L
Linus Torvalds 已提交
60 61 62 63 64 65 66 67 68 69 70 71 72 73 74
	static struct super_operations default_op;

	if (s) {
		if (security_sb_alloc(s)) {
			kfree(s);
			s = NULL;
			goto out;
		}
		INIT_LIST_HEAD(&s->s_dirty);
		INIT_LIST_HEAD(&s->s_io);
		INIT_LIST_HEAD(&s->s_files);
		INIT_LIST_HEAD(&s->s_instances);
		INIT_HLIST_HEAD(&s->s_anon);
		INIT_LIST_HEAD(&s->s_inodes);
		init_rwsem(&s->s_umount);
75
		mutex_init(&s->s_lock);
76
		lockdep_set_class(&s->s_umount, &type->s_umount_key);
I
Ingo Molnar 已提交
77 78 79 80 81 82
		/*
		 * The locking rules for s_lock are up to the
		 * filesystem. For example ext3fs has different
		 * lock ordering than usbfs:
		 */
		lockdep_set_class(&s->s_lock, &type->s_lock_key);
L
Linus Torvalds 已提交
83 84 85
		down_write(&s->s_umount);
		s->s_count = S_BIAS;
		atomic_set(&s->s_active, 1);
86
		mutex_init(&s->s_vfs_rename_mutex);
I
Ingo Molnar 已提交
87 88
		mutex_init(&s->s_dquot.dqio_mutex);
		mutex_init(&s->s_dquot.dqonoff_mutex);
L
Linus Torvalds 已提交
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180
		init_rwsem(&s->s_dquot.dqptr_sem);
		init_waitqueue_head(&s->s_wait_unfrozen);
		s->s_maxbytes = MAX_NON_LFS;
		s->dq_op = sb_dquot_ops;
		s->s_qcop = sb_quotactl_ops;
		s->s_op = &default_op;
		s->s_time_gran = 1000000000;
	}
out:
	return s;
}

/**
 *	destroy_super	-	frees a superblock
 *	@s: superblock to free
 *
 *	Frees a superblock.
 */
static inline void destroy_super(struct super_block *s)
{
	security_sb_free(s);
	kfree(s);
}

/* Superblock refcounting  */

/*
 * Drop a superblock's refcount.  Returns non-zero if the superblock was
 * destroyed.  The caller must hold sb_lock.
 */
int __put_super(struct super_block *sb)
{
	int ret = 0;

	if (!--sb->s_count) {
		destroy_super(sb);
		ret = 1;
	}
	return ret;
}

/*
 * Drop a superblock's refcount.
 * Returns non-zero if the superblock is about to be destroyed and
 * at least is already removed from super_blocks list, so if we are
 * making a loop through super blocks then we need to restart.
 * The caller must hold sb_lock.
 */
int __put_super_and_need_restart(struct super_block *sb)
{
	/* check for race with generic_shutdown_super() */
	if (list_empty(&sb->s_list)) {
		/* super block is removed, need to restart... */
		__put_super(sb);
		return 1;
	}
	/* can't be the last, since s_list is still in use */
	sb->s_count--;
	BUG_ON(sb->s_count == 0);
	return 0;
}

/**
 *	put_super	-	drop a temporary reference to superblock
 *	@sb: superblock in question
 *
 *	Drops a temporary reference, frees superblock if there's no
 *	references left.
 */
static void put_super(struct super_block *sb)
{
	spin_lock(&sb_lock);
	__put_super(sb);
	spin_unlock(&sb_lock);
}


/**
 *	deactivate_super	-	drop an active reference to superblock
 *	@s: superblock to deactivate
 *
 *	Drops an active reference to superblock, acquiring a temprory one if
 *	there is no active references left.  In that case we lock superblock,
 *	tell fs driver to shut it down and drop the temporary reference we
 *	had just acquired.
 */
void deactivate_super(struct super_block *s)
{
	struct file_system_type *fs = s->s_type;
	if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
		s->s_count -= S_BIAS-1;
		spin_unlock(&sb_lock);
181
		DQUOT_OFF(s);
L
Linus Torvalds 已提交
182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201
		down_write(&s->s_umount);
		fs->kill_sb(s);
		put_filesystem(fs);
		put_super(s);
	}
}

EXPORT_SYMBOL(deactivate_super);

/**
 *	grab_super - acquire an active reference
 *	@s: reference we are trying to make active
 *
 *	Tries to acquire an active reference.  grab_super() is used when we
 * 	had just found a superblock in super_blocks or fs_type->fs_supers
 *	and want to turn it into a full-blown active reference.  grab_super()
 *	is called with sb_lock held and drops it.  Returns 1 in case of
 *	success, 0 if we had failed (superblock contents was already dead or
 *	dying when grab_super() had been called).
 */
202
static int grab_super(struct super_block *s) __releases(sb_lock)
L
Linus Torvalds 已提交
203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240
{
	s->s_count++;
	spin_unlock(&sb_lock);
	down_write(&s->s_umount);
	if (s->s_root) {
		spin_lock(&sb_lock);
		if (s->s_count > S_BIAS) {
			atomic_inc(&s->s_active);
			s->s_count--;
			spin_unlock(&sb_lock);
			return 1;
		}
		spin_unlock(&sb_lock);
	}
	up_write(&s->s_umount);
	put_super(s);
	yield();
	return 0;
}

/**
 *	generic_shutdown_super	-	common helper for ->kill_sb()
 *	@sb: superblock to kill
 *
 *	generic_shutdown_super() does all fs-independent work on superblock
 *	shutdown.  Typical ->kill_sb() should pick all fs-specific objects
 *	that need destruction out of superblock, call generic_shutdown_super()
 *	and release aforementioned objects.  Note: dentries and inodes _are_
 *	taken care of and do not need specific handling.
 */
void generic_shutdown_super(struct super_block *sb)
{
	struct dentry *root = sb->s_root;
	struct super_operations *sop = sb->s_op;

	if (root) {
		sb->s_root = NULL;
		shrink_dcache_parent(root);
241
		shrink_dcache_sb(sb);
L
Linus Torvalds 已提交
242 243 244 245 246 247 248 249 250 251 252 253 254 255 256
		dput(root);
		fsync_super(sb);
		lock_super(sb);
		sb->s_flags &= ~MS_ACTIVE;
		/* bad name - it should be evict_inodes() */
		invalidate_inodes(sb);
		lock_kernel();

		if (sop->write_super && sb->s_dirt)
			sop->write_super(sb);
		if (sop->put_super)
			sop->put_super(sb);

		/* Forget any remaining inodes */
		if (invalidate_inodes(sb)) {
257 258 259
			printk("VFS: Busy inodes after unmount of %s. "
			   "Self-destruct in 5 seconds.  Have a nice day...\n",
			   sb->s_id);
L
Linus Torvalds 已提交
260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305
		}

		unlock_kernel();
		unlock_super(sb);
	}
	spin_lock(&sb_lock);
	/* should be initialized for __put_super_and_need_restart() */
	list_del_init(&sb->s_list);
	list_del(&sb->s_instances);
	spin_unlock(&sb_lock);
	up_write(&sb->s_umount);
}

EXPORT_SYMBOL(generic_shutdown_super);

/**
 *	sget	-	find or create a superblock
 *	@type:	filesystem type superblock should belong to
 *	@test:	comparison callback
 *	@set:	setup callback
 *	@data:	argument to each of them
 */
struct super_block *sget(struct file_system_type *type,
			int (*test)(struct super_block *,void *),
			int (*set)(struct super_block *,void *),
			void *data)
{
	struct super_block *s = NULL;
	struct list_head *p;
	int err;

retry:
	spin_lock(&sb_lock);
	if (test) list_for_each(p, &type->fs_supers) {
		struct super_block *old;
		old = list_entry(p, struct super_block, s_instances);
		if (!test(old, data))
			continue;
		if (!grab_super(old))
			goto retry;
		if (s)
			destroy_super(s);
		return old;
	}
	if (!s) {
		spin_unlock(&sb_lock);
I
Ingo Molnar 已提交
306
		s = alloc_super(type);
L
Linus Torvalds 已提交
307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352
		if (!s)
			return ERR_PTR(-ENOMEM);
		goto retry;
	}
		
	err = set(s, data);
	if (err) {
		spin_unlock(&sb_lock);
		destroy_super(s);
		return ERR_PTR(err);
	}
	s->s_type = type;
	strlcpy(s->s_id, type->name, sizeof(s->s_id));
	list_add_tail(&s->s_list, &super_blocks);
	list_add(&s->s_instances, &type->fs_supers);
	spin_unlock(&sb_lock);
	get_filesystem(type);
	return s;
}

EXPORT_SYMBOL(sget);

void drop_super(struct super_block *sb)
{
	up_read(&sb->s_umount);
	put_super(sb);
}

EXPORT_SYMBOL(drop_super);

static inline void write_super(struct super_block *sb)
{
	lock_super(sb);
	if (sb->s_root && sb->s_dirt)
		if (sb->s_op->write_super)
			sb->s_op->write_super(sb);
	unlock_super(sb);
}

/*
 * Note: check the dirty flag before waiting, so we don't
 * hold up the sync while mounting a device. (The newly
 * mounted device won't need syncing.)
 */
void sync_supers(void)
{
353 354
	struct super_block *sb;

L
Linus Torvalds 已提交
355
	spin_lock(&sb_lock);
356 357
restart:
	list_for_each_entry(sb, &super_blocks, s_list) {
L
Linus Torvalds 已提交
358 359 360 361 362
		if (sb->s_dirt) {
			sb->s_count++;
			spin_unlock(&sb_lock);
			down_read(&sb->s_umount);
			write_super(sb);
363 364 365 366 367 368
			up_read(&sb->s_umount);
			spin_lock(&sb_lock);
			if (__put_super_and_need_restart(sb))
				goto restart;
		}
	}
L
Linus Torvalds 已提交
369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390
	spin_unlock(&sb_lock);
}

/*
 * Call the ->sync_fs super_op against all filesytems which are r/w and
 * which implement it.
 *
 * This operation is careful to avoid the livelock which could easily happen
 * if two or more filesystems are being continuously dirtied.  s_need_sync_fs
 * is used only here.  We set it against all filesystems and then clear it as
 * we sync them.  So redirtied filesystems are skipped.
 *
 * But if process A is currently running sync_filesytems and then process B
 * calls sync_filesystems as well, process B will set all the s_need_sync_fs
 * flags again, which will cause process A to resync everything.  Fix that with
 * a local mutex.
 *
 * (Fabian) Avoid sync_fs with clean fs & wait mode 0
 */
void sync_filesystems(int wait)
{
	struct super_block *sb;
I
Ingo Molnar 已提交
391
	static DEFINE_MUTEX(mutex);
L
Linus Torvalds 已提交
392

I
Ingo Molnar 已提交
393
	mutex_lock(&mutex);		/* Could be down_interruptible */
L
Linus Torvalds 已提交
394
	spin_lock(&sb_lock);
395
	list_for_each_entry(sb, &super_blocks, s_list) {
L
Linus Torvalds 已提交
396 397 398 399 400 401 402 403
		if (!sb->s_op->sync_fs)
			continue;
		if (sb->s_flags & MS_RDONLY)
			continue;
		sb->s_need_sync_fs = 1;
	}

restart:
404
	list_for_each_entry(sb, &super_blocks, s_list) {
L
Linus Torvalds 已提交
405 406 407 408 409 410 411 412 413 414
		if (!sb->s_need_sync_fs)
			continue;
		sb->s_need_sync_fs = 0;
		if (sb->s_flags & MS_RDONLY)
			continue;	/* hm.  Was remounted r/o meanwhile */
		sb->s_count++;
		spin_unlock(&sb_lock);
		down_read(&sb->s_umount);
		if (sb->s_root && (wait || sb->s_dirt))
			sb->s_op->sync_fs(sb, wait);
415 416 417 418 419
		up_read(&sb->s_umount);
		/* restart only when sb is no longer on the list */
		spin_lock(&sb_lock);
		if (__put_super_and_need_restart(sb))
			goto restart;
L
Linus Torvalds 已提交
420 421
	}
	spin_unlock(&sb_lock);
I
Ingo Molnar 已提交
422
	mutex_unlock(&mutex);
L
Linus Torvalds 已提交
423 424 425 426 427 428 429 430 431 432 433 434
}

/**
 *	get_super - get the superblock of a device
 *	@bdev: device to get the superblock for
 *	
 *	Scans the superblock list and finds the superblock of the file system
 *	mounted on the device given. %NULL is returned if no match is found.
 */

struct super_block * get_super(struct block_device *bdev)
{
435 436
	struct super_block *sb;

L
Linus Torvalds 已提交
437 438
	if (!bdev)
		return NULL;
439

L
Linus Torvalds 已提交
440
	spin_lock(&sb_lock);
441 442 443 444
rescan:
	list_for_each_entry(sb, &super_blocks, s_list) {
		if (sb->s_bdev == bdev) {
			sb->s_count++;
L
Linus Torvalds 已提交
445
			spin_unlock(&sb_lock);
446 447 448 449 450 451 452 453
			down_read(&sb->s_umount);
			if (sb->s_root)
				return sb;
			up_read(&sb->s_umount);
			/* restart only when sb is no longer on the list */
			spin_lock(&sb_lock);
			if (__put_super_and_need_restart(sb))
				goto rescan;
L
Linus Torvalds 已提交
454 455 456 457 458 459 460 461 462 463
		}
	}
	spin_unlock(&sb_lock);
	return NULL;
}

EXPORT_SYMBOL(get_super);
 
struct super_block * user_get_super(dev_t dev)
{
464
	struct super_block *sb;
L
Linus Torvalds 已提交
465 466

	spin_lock(&sb_lock);
467 468 469 470
rescan:
	list_for_each_entry(sb, &super_blocks, s_list) {
		if (sb->s_dev ==  dev) {
			sb->s_count++;
L
Linus Torvalds 已提交
471
			spin_unlock(&sb_lock);
472 473 474 475 476 477 478 479
			down_read(&sb->s_umount);
			if (sb->s_root)
				return sb;
			up_read(&sb->s_umount);
			/* restart only when sb is no longer on the list */
			spin_lock(&sb_lock);
			if (__put_super_and_need_restart(sb))
				goto rescan;
L
Linus Torvalds 已提交
480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495
		}
	}
	spin_unlock(&sb_lock);
	return NULL;
}

asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf)
{
        struct super_block *s;
        struct ustat tmp;
        struct kstatfs sbuf;
	int err = -EINVAL;

        s = user_get_super(new_decode_dev(dev));
        if (s == NULL)
                goto out;
496
	err = vfs_statfs(s->s_root, &sbuf);
L
Linus Torvalds 已提交
497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522
	drop_super(s);
	if (err)
		goto out;

        memset(&tmp,0,sizeof(struct ustat));
        tmp.f_tfree = sbuf.f_bfree;
        tmp.f_tinode = sbuf.f_ffree;

        err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
out:
	return err;
}

/**
 *	mark_files_ro
 *	@sb: superblock in question
 *
 *	All files are marked read/only.  We don't care about pending
 *	delete files so this should be used in 'force' mode only
 */

static void mark_files_ro(struct super_block *sb)
{
	struct file *f;

	file_list_lock();
E
Eric Dumazet 已提交
523
	list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
L
Linus Torvalds 已提交
524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675
		if (S_ISREG(f->f_dentry->d_inode->i_mode) && file_count(f))
			f->f_mode &= ~FMODE_WRITE;
	}
	file_list_unlock();
}

/**
 *	do_remount_sb - asks filesystem to change mount options.
 *	@sb:	superblock in question
 *	@flags:	numeric part of options
 *	@data:	the rest of options
 *      @force: whether or not to force the change
 *
 *	Alters the mount options of a mounted file system.
 */
int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
{
	int retval;
	
	if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
		return -EACCES;
	if (flags & MS_RDONLY)
		acct_auto_close(sb);
	shrink_dcache_sb(sb);
	fsync_super(sb);

	/* If we are remounting RDONLY and current sb is read/write,
	   make sure there are no rw files opened */
	if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
		if (force)
			mark_files_ro(sb);
		else if (!fs_may_remount_ro(sb))
			return -EBUSY;
	}

	if (sb->s_op->remount_fs) {
		lock_super(sb);
		retval = sb->s_op->remount_fs(sb, &flags, data);
		unlock_super(sb);
		if (retval)
			return retval;
	}
	sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
	return 0;
}

static void do_emergency_remount(unsigned long foo)
{
	struct super_block *sb;

	spin_lock(&sb_lock);
	list_for_each_entry(sb, &super_blocks, s_list) {
		sb->s_count++;
		spin_unlock(&sb_lock);
		down_read(&sb->s_umount);
		if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
			/*
			 * ->remount_fs needs lock_kernel().
			 *
			 * What lock protects sb->s_flags??
			 */
			lock_kernel();
			do_remount_sb(sb, MS_RDONLY, NULL, 1);
			unlock_kernel();
		}
		drop_super(sb);
		spin_lock(&sb_lock);
	}
	spin_unlock(&sb_lock);
	printk("Emergency Remount complete\n");
}

void emergency_remount(void)
{
	pdflush_operation(do_emergency_remount, 0);
}

/*
 * Unnamed block devices are dummy devices used by virtual
 * filesystems which don't use real block-devices.  -- jrs
 */

static struct idr unnamed_dev_idr;
static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */

int set_anon_super(struct super_block *s, void *data)
{
	int dev;
	int error;

 retry:
	if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0)
		return -ENOMEM;
	spin_lock(&unnamed_dev_lock);
	error = idr_get_new(&unnamed_dev_idr, NULL, &dev);
	spin_unlock(&unnamed_dev_lock);
	if (error == -EAGAIN)
		/* We raced and lost with another CPU. */
		goto retry;
	else if (error)
		return -EAGAIN;

	if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
		spin_lock(&unnamed_dev_lock);
		idr_remove(&unnamed_dev_idr, dev);
		spin_unlock(&unnamed_dev_lock);
		return -EMFILE;
	}
	s->s_dev = MKDEV(0, dev & MINORMASK);
	return 0;
}

EXPORT_SYMBOL(set_anon_super);

void kill_anon_super(struct super_block *sb)
{
	int slot = MINOR(sb->s_dev);

	generic_shutdown_super(sb);
	spin_lock(&unnamed_dev_lock);
	idr_remove(&unnamed_dev_idr, slot);
	spin_unlock(&unnamed_dev_lock);
}

EXPORT_SYMBOL(kill_anon_super);

void __init unnamed_dev_init(void)
{
	idr_init(&unnamed_dev_idr);
}

void kill_litter_super(struct super_block *sb)
{
	if (sb->s_root)
		d_genocide(sb->s_root);
	kill_anon_super(sb);
}

EXPORT_SYMBOL(kill_litter_super);

static int set_bdev_super(struct super_block *s, void *data)
{
	s->s_bdev = data;
	s->s_dev = s->s_bdev->bd_dev;
	return 0;
}

static int test_bdev_super(struct super_block *s, void *data)
{
	return (void *)s->s_bdev == data;
}

676 677 678 679 680 681 682 683 684 685
static void bdev_uevent(struct block_device *bdev, enum kobject_action action)
{
	if (bdev->bd_disk) {
		if (bdev->bd_part)
			kobject_uevent(&bdev->bd_part->kobj, action);
		else
			kobject_uevent(&bdev->bd_disk->kobj, action);
	}
}

686
int get_sb_bdev(struct file_system_type *fs_type,
L
Linus Torvalds 已提交
687
	int flags, const char *dev_name, void *data,
688 689
	int (*fill_super)(struct super_block *, void *, int),
	struct vfsmount *mnt)
L
Linus Torvalds 已提交
690 691 692 693 694 695 696
{
	struct block_device *bdev;
	struct super_block *s;
	int error = 0;

	bdev = open_bdev_excl(dev_name, flags, fs_type);
	if (IS_ERR(bdev))
697
		return PTR_ERR(bdev);
L
Linus Torvalds 已提交
698 699 700 701 702 703

	/*
	 * once the super is inserted into the list by sget, s_umount
	 * will protect the lockfs code from trying to start a snapshot
	 * while we are mounting
	 */
704
	mutex_lock(&bdev->bd_mount_mutex);
L
Linus Torvalds 已提交
705
	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
706
	mutex_unlock(&bdev->bd_mount_mutex);
L
Linus Torvalds 已提交
707
	if (IS_ERR(s))
708
		goto error_s;
L
Linus Torvalds 已提交
709 710 711 712 713

	if (s->s_root) {
		if ((flags ^ s->s_flags) & MS_RDONLY) {
			up_write(&s->s_umount);
			deactivate_super(s);
714 715
			error = -EBUSY;
			goto error_bdev;
L
Linus Torvalds 已提交
716
		}
717 718

		close_bdev_excl(bdev);
L
Linus Torvalds 已提交
719 720 721 722 723
	} else {
		char b[BDEVNAME_SIZE];

		s->s_flags = flags;
		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
724
		sb_set_blocksize(s, block_size(bdev));
725
		error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
L
Linus Torvalds 已提交
726 727 728
		if (error) {
			up_write(&s->s_umount);
			deactivate_super(s);
729
			goto error;
730
		}
731 732 733

		s->s_flags |= MS_ACTIVE;
		bdev_uevent(bdev, KOBJ_MOUNT);
L
Linus Torvalds 已提交
734 735
	}

736
	return simple_set_mnt(mnt, s);
L
Linus Torvalds 已提交
737

738 739 740
error_s:
	error = PTR_ERR(s);
error_bdev:
L
Linus Torvalds 已提交
741
	close_bdev_excl(bdev);
742 743
error:
	return error;
L
Linus Torvalds 已提交
744 745 746 747 748 749 750 751
}

EXPORT_SYMBOL(get_sb_bdev);

void kill_block_super(struct super_block *sb)
{
	struct block_device *bdev = sb->s_bdev;

752
	bdev_uevent(bdev, KOBJ_UMOUNT);
L
Linus Torvalds 已提交
753 754 755 756 757 758 759
	generic_shutdown_super(sb);
	sync_blockdev(bdev);
	close_bdev_excl(bdev);
}

EXPORT_SYMBOL(kill_block_super);

760
int get_sb_nodev(struct file_system_type *fs_type,
L
Linus Torvalds 已提交
761
	int flags, void *data,
762 763
	int (*fill_super)(struct super_block *, void *, int),
	struct vfsmount *mnt)
L
Linus Torvalds 已提交
764 765 766 767 768
{
	int error;
	struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);

	if (IS_ERR(s))
769
		return PTR_ERR(s);
L
Linus Torvalds 已提交
770 771 772

	s->s_flags = flags;

773
	error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
L
Linus Torvalds 已提交
774 775 776
	if (error) {
		up_write(&s->s_umount);
		deactivate_super(s);
777
		return error;
L
Linus Torvalds 已提交
778 779
	}
	s->s_flags |= MS_ACTIVE;
780
	return simple_set_mnt(mnt, s);
L
Linus Torvalds 已提交
781 782 783 784 785 786 787 788 789
}

EXPORT_SYMBOL(get_sb_nodev);

static int compare_single(struct super_block *s, void *p)
{
	return 1;
}

790
int get_sb_single(struct file_system_type *fs_type,
L
Linus Torvalds 已提交
791
	int flags, void *data,
792 793
	int (*fill_super)(struct super_block *, void *, int),
	struct vfsmount *mnt)
L
Linus Torvalds 已提交
794 795 796 797 798 799
{
	struct super_block *s;
	int error;

	s = sget(fs_type, compare_single, set_anon_super, NULL);
	if (IS_ERR(s))
800
		return PTR_ERR(s);
L
Linus Torvalds 已提交
801 802
	if (!s->s_root) {
		s->s_flags = flags;
803
		error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
L
Linus Torvalds 已提交
804 805 806
		if (error) {
			up_write(&s->s_umount);
			deactivate_super(s);
807
			return error;
L
Linus Torvalds 已提交
808 809 810 811
		}
		s->s_flags |= MS_ACTIVE;
	}
	do_remount_sb(s, flags, data, 0);
812
	return simple_set_mnt(mnt, s);
L
Linus Torvalds 已提交
813 814 815 816 817
}

EXPORT_SYMBOL(get_sb_single);

struct vfsmount *
818
vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
L
Linus Torvalds 已提交
819 820 821
{
	struct vfsmount *mnt;
	char *secdata = NULL;
822
	int error;
L
Linus Torvalds 已提交
823 824 825 826

	if (!type)
		return ERR_PTR(-ENODEV);

827
	error = -ENOMEM;
L
Linus Torvalds 已提交
828 829 830 831 832 833
	mnt = alloc_vfsmnt(name);
	if (!mnt)
		goto out;

	if (data) {
		secdata = alloc_secdata();
834
		if (!secdata)
L
Linus Torvalds 已提交
835 836 837
			goto out_mnt;

		error = security_sb_copy_data(type, data, secdata);
838
		if (error)
L
Linus Torvalds 已提交
839 840 841
			goto out_free_secdata;
	}

842 843
	error = type->get_sb(type, flags, name, data, mnt);
	if (error < 0)
L
Linus Torvalds 已提交
844
		goto out_free_secdata;
845 846

 	error = security_sb_kern_mount(mnt->mnt_sb, secdata);
L
Linus Torvalds 已提交
847 848
 	if (error)
 		goto out_sb;
849 850

	mnt->mnt_mountpoint = mnt->mnt_root;
L
Linus Torvalds 已提交
851
	mnt->mnt_parent = mnt;
852
	up_write(&mnt->mnt_sb->s_umount);
853
	free_secdata(secdata);
L
Linus Torvalds 已提交
854 855
	return mnt;
out_sb:
856 857 858
	dput(mnt->mnt_root);
	up_write(&mnt->mnt_sb->s_umount);
	deactivate_super(mnt->mnt_sb);
L
Linus Torvalds 已提交
859 860 861 862 863
out_free_secdata:
	free_secdata(secdata);
out_mnt:
	free_vfsmnt(mnt);
out:
864
	return ERR_PTR(error);
L
Linus Torvalds 已提交
865 866
}

867 868 869 870 871 872 873 874 875 876 877 878 879 880
EXPORT_SYMBOL_GPL(vfs_kern_mount);

struct vfsmount *
do_kern_mount(const char *fstype, int flags, const char *name, void *data)
{
	struct file_system_type *type = get_fs_type(fstype);
	struct vfsmount *mnt;
	if (!type)
		return ERR_PTR(-ENODEV);
	mnt = vfs_kern_mount(type, flags, name, data);
	put_filesystem(type);
	return mnt;
}

L
Linus Torvalds 已提交
881 882
struct vfsmount *kern_mount(struct file_system_type *type)
{
883
	return vfs_kern_mount(type, 0, type->name, NULL);
L
Linus Torvalds 已提交
884 885 886
}

EXPORT_SYMBOL(kern_mount);