aboutsummaryrefslogtreecommitdiffstats
path: root/fs/namespace.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c1465
1 files changed, 1465 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
new file mode 100644
index 000000000000..3b93e5d750eb
--- /dev/null
+++ b/fs/namespace.c
@@ -0,0 +1,1465 @@
1/*
2 * linux/fs/namespace.c
3 *
4 * (C) Copyright Al Viro 2000, 2001
5 * Released under GPL v2.
6 *
7 * Based on code from fs/super.c, copyright Linus Torvalds and others.
8 * Heavily rewritten.
9 */
10
11#include <linux/config.h>
12#include <linux/syscalls.h>
13#include <linux/slab.h>
14#include <linux/sched.h>
15#include <linux/smp_lock.h>
16#include <linux/init.h>
17#include <linux/quotaops.h>
18#include <linux/acct.h>
19#include <linux/module.h>
20#include <linux/seq_file.h>
21#include <linux/namespace.h>
22#include <linux/namei.h>
23#include <linux/security.h>
24#include <linux/mount.h>
25#include <asm/uaccess.h>
26#include <asm/unistd.h>
27
28extern int __init init_rootfs(void);
29
30#ifdef CONFIG_SYSFS
31extern int __init sysfs_init(void);
32#else
33static inline int sysfs_init(void)
34{
35 return 0;
36}
37#endif
38
39/* spinlock for vfsmount related operations, inplace of dcache_lock */
40 __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
41
42static struct list_head *mount_hashtable;
43static int hash_mask, hash_bits;
44static kmem_cache_t *mnt_cache;
45
46static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
47{
48 unsigned long tmp = ((unsigned long) mnt / L1_CACHE_BYTES);
49 tmp += ((unsigned long) dentry / L1_CACHE_BYTES);
50 tmp = tmp + (tmp >> hash_bits);
51 return tmp & hash_mask;
52}
53
54struct vfsmount *alloc_vfsmnt(const char *name)
55{
56 struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
57 if (mnt) {
58 memset(mnt, 0, sizeof(struct vfsmount));
59 atomic_set(&mnt->mnt_count,1);
60 INIT_LIST_HEAD(&mnt->mnt_hash);
61 INIT_LIST_HEAD(&mnt->mnt_child);
62 INIT_LIST_HEAD(&mnt->mnt_mounts);
63 INIT_LIST_HEAD(&mnt->mnt_list);
64 INIT_LIST_HEAD(&mnt->mnt_fslink);
65 if (name) {
66 int size = strlen(name)+1;
67 char *newname = kmalloc(size, GFP_KERNEL);
68 if (newname) {
69 memcpy(newname, name, size);
70 mnt->mnt_devname = newname;
71 }
72 }
73 }
74 return mnt;
75}
76
77void free_vfsmnt(struct vfsmount *mnt)
78{
79 kfree(mnt->mnt_devname);
80 kmem_cache_free(mnt_cache, mnt);
81}
82
83/*
84 * Now, lookup_mnt increments the ref count before returning
85 * the vfsmount struct.
86 */
87struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
88{
89 struct list_head * head = mount_hashtable + hash(mnt, dentry);
90 struct list_head * tmp = head;
91 struct vfsmount *p, *found = NULL;
92
93 spin_lock(&vfsmount_lock);
94 for (;;) {
95 tmp = tmp->next;
96 p = NULL;
97 if (tmp == head)
98 break;
99 p = list_entry(tmp, struct vfsmount, mnt_hash);
100 if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) {
101 found = mntget(p);
102 break;
103 }
104 }
105 spin_unlock(&vfsmount_lock);
106 return found;
107}
108
109static inline int check_mnt(struct vfsmount *mnt)
110{
111 return mnt->mnt_namespace == current->namespace;
112}
113
114static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
115{
116 old_nd->dentry = mnt->mnt_mountpoint;
117 old_nd->mnt = mnt->mnt_parent;
118 mnt->mnt_parent = mnt;
119 mnt->mnt_mountpoint = mnt->mnt_root;
120 list_del_init(&mnt->mnt_child);
121 list_del_init(&mnt->mnt_hash);
122 old_nd->dentry->d_mounted--;
123}
124
125static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
126{
127 mnt->mnt_parent = mntget(nd->mnt);
128 mnt->mnt_mountpoint = dget(nd->dentry);
129 list_add(&mnt->mnt_hash, mount_hashtable+hash(nd->mnt, nd->dentry));
130 list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts);
131 nd->dentry->d_mounted++;
132}
133
134static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root)
135{
136 struct list_head *next = p->mnt_mounts.next;
137 if (next == &p->mnt_mounts) {
138 while (1) {
139 if (p == root)
140 return NULL;
141 next = p->mnt_child.next;
142 if (next != &p->mnt_parent->mnt_mounts)
143 break;
144 p = p->mnt_parent;
145 }
146 }
147 return list_entry(next, struct vfsmount, mnt_child);
148}
149
150static struct vfsmount *
151clone_mnt(struct vfsmount *old, struct dentry *root)
152{
153 struct super_block *sb = old->mnt_sb;
154 struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
155
156 if (mnt) {
157 mnt->mnt_flags = old->mnt_flags;
158 atomic_inc(&sb->s_active);
159 mnt->mnt_sb = sb;
160 mnt->mnt_root = dget(root);
161 mnt->mnt_mountpoint = mnt->mnt_root;
162 mnt->mnt_parent = mnt;
163 mnt->mnt_namespace = old->mnt_namespace;
164
165 /* stick the duplicate mount on the same expiry list
166 * as the original if that was on one */
167 spin_lock(&vfsmount_lock);
168 if (!list_empty(&old->mnt_fslink))
169 list_add(&mnt->mnt_fslink, &old->mnt_fslink);
170 spin_unlock(&vfsmount_lock);
171 }
172 return mnt;
173}
174
175void __mntput(struct vfsmount *mnt)
176{
177 struct super_block *sb = mnt->mnt_sb;
178 dput(mnt->mnt_root);
179 free_vfsmnt(mnt);
180 deactivate_super(sb);
181}
182
183EXPORT_SYMBOL(__mntput);
184
185/* iterator */
186static void *m_start(struct seq_file *m, loff_t *pos)
187{
188 struct namespace *n = m->private;
189 struct list_head *p;
190 loff_t l = *pos;
191
192 down_read(&n->sem);
193 list_for_each(p, &n->list)
194 if (!l--)
195 return list_entry(p, struct vfsmount, mnt_list);
196 return NULL;
197}
198
199static void *m_next(struct seq_file *m, void *v, loff_t *pos)
200{
201 struct namespace *n = m->private;
202 struct list_head *p = ((struct vfsmount *)v)->mnt_list.next;
203 (*pos)++;
204 return p==&n->list ? NULL : list_entry(p, struct vfsmount, mnt_list);
205}
206
207static void m_stop(struct seq_file *m, void *v)
208{
209 struct namespace *n = m->private;
210 up_read(&n->sem);
211}
212
213static inline void mangle(struct seq_file *m, const char *s)
214{
215 seq_escape(m, s, " \t\n\\");
216}
217
218static int show_vfsmnt(struct seq_file *m, void *v)
219{
220 struct vfsmount *mnt = v;
221 int err = 0;
222 static struct proc_fs_info {
223 int flag;
224 char *str;
225 } fs_info[] = {
226 { MS_SYNCHRONOUS, ",sync" },
227 { MS_DIRSYNC, ",dirsync" },
228 { MS_MANDLOCK, ",mand" },
229 { MS_NOATIME, ",noatime" },
230 { MS_NODIRATIME, ",nodiratime" },
231 { 0, NULL }
232 };
233 static struct proc_fs_info mnt_info[] = {
234 { MNT_NOSUID, ",nosuid" },
235 { MNT_NODEV, ",nodev" },
236 { MNT_NOEXEC, ",noexec" },
237 { 0, NULL }
238 };
239 struct proc_fs_info *fs_infop;
240
241 mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
242 seq_putc(m, ' ');
243 seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
244 seq_putc(m, ' ');
245 mangle(m, mnt->mnt_sb->s_type->name);
246 seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw");
247 for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
248 if (mnt->mnt_sb->s_flags & fs_infop->flag)
249 seq_puts(m, fs_infop->str);
250 }
251 for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
252 if (mnt->mnt_flags & fs_infop->flag)
253 seq_puts(m, fs_infop->str);
254 }
255 if (mnt->mnt_sb->s_op->show_options)
256 err = mnt->mnt_sb->s_op->show_options(m, mnt);
257 seq_puts(m, " 0 0\n");
258 return err;
259}
260
261struct seq_operations mounts_op = {
262 .start = m_start,
263 .next = m_next,
264 .stop = m_stop,
265 .show = show_vfsmnt
266};
267
268/**
269 * may_umount_tree - check if a mount tree is busy
270 * @mnt: root of mount tree
271 *
272 * This is called to check if a tree of mounts has any
273 * open files, pwds, chroots or sub mounts that are
274 * busy.
275 */
276int may_umount_tree(struct vfsmount *mnt)
277{
278 struct list_head *next;
279 struct vfsmount *this_parent = mnt;
280 int actual_refs;
281 int minimum_refs;
282
283 spin_lock(&vfsmount_lock);
284 actual_refs = atomic_read(&mnt->mnt_count);
285 minimum_refs = 2;
286repeat:
287 next = this_parent->mnt_mounts.next;
288resume:
289 while (next != &this_parent->mnt_mounts) {
290 struct vfsmount *p = list_entry(next, struct vfsmount, mnt_child);
291
292 next = next->next;
293
294 actual_refs += atomic_read(&p->mnt_count);
295 minimum_refs += 2;
296
297 if (!list_empty(&p->mnt_mounts)) {
298 this_parent = p;
299 goto repeat;
300 }
301 }
302
303 if (this_parent != mnt) {
304 next = this_parent->mnt_child.next;
305 this_parent = this_parent->mnt_parent;
306 goto resume;
307 }
308 spin_unlock(&vfsmount_lock);
309
310 if (actual_refs > minimum_refs)
311 return -EBUSY;
312
313 return 0;
314}
315
316EXPORT_SYMBOL(may_umount_tree);
317
318/**
319 * may_umount - check if a mount point is busy
320 * @mnt: root of mount
321 *
322 * This is called to check if a mount point has any
323 * open files, pwds, chroots or sub mounts. If the
324 * mount has sub mounts this will return busy
325 * regardless of whether the sub mounts are busy.
326 *
327 * Doesn't take quota and stuff into account. IOW, in some cases it will
328 * give false negatives. The main reason why it's here is that we need
329 * a non-destructive way to look for easily umountable filesystems.
330 */
331int may_umount(struct vfsmount *mnt)
332{
333 if (atomic_read(&mnt->mnt_count) > 2)
334 return -EBUSY;
335 return 0;
336}
337
338EXPORT_SYMBOL(may_umount);
339
340void umount_tree(struct vfsmount *mnt)
341{
342 struct vfsmount *p;
343 LIST_HEAD(kill);
344
345 for (p = mnt; p; p = next_mnt(p, mnt)) {
346 list_del(&p->mnt_list);
347 list_add(&p->mnt_list, &kill);
348 }
349
350 while (!list_empty(&kill)) {
351 mnt = list_entry(kill.next, struct vfsmount, mnt_list);
352 list_del_init(&mnt->mnt_list);
353 list_del_init(&mnt->mnt_fslink);
354 if (mnt->mnt_parent == mnt) {
355 spin_unlock(&vfsmount_lock);
356 } else {
357 struct nameidata old_nd;
358 detach_mnt(mnt, &old_nd);
359 spin_unlock(&vfsmount_lock);
360 path_release(&old_nd);
361 }
362 mntput(mnt);
363 spin_lock(&vfsmount_lock);
364 }
365}
366
367static int do_umount(struct vfsmount *mnt, int flags)
368{
369 struct super_block * sb = mnt->mnt_sb;
370 int retval;
371
372 retval = security_sb_umount(mnt, flags);
373 if (retval)
374 return retval;
375
376 /*
377 * Allow userspace to request a mountpoint be expired rather than
378 * unmounting unconditionally. Unmount only happens if:
379 * (1) the mark is already set (the mark is cleared by mntput())
380 * (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount]
381 */
382 if (flags & MNT_EXPIRE) {
383 if (mnt == current->fs->rootmnt ||
384 flags & (MNT_FORCE | MNT_DETACH))
385 return -EINVAL;
386
387 if (atomic_read(&mnt->mnt_count) != 2)
388 return -EBUSY;
389
390 if (!xchg(&mnt->mnt_expiry_mark, 1))
391 return -EAGAIN;
392 }
393
394 /*
395 * If we may have to abort operations to get out of this
396 * mount, and they will themselves hold resources we must
397 * allow the fs to do things. In the Unix tradition of
398 * 'Gee thats tricky lets do it in userspace' the umount_begin
399 * might fail to complete on the first run through as other tasks
400 * must return, and the like. Thats for the mount program to worry
401 * about for the moment.
402 */
403
404 lock_kernel();
405 if( (flags&MNT_FORCE) && sb->s_op->umount_begin)
406 sb->s_op->umount_begin(sb);
407 unlock_kernel();
408
409 /*
410 * No sense to grab the lock for this test, but test itself looks
411 * somewhat bogus. Suggestions for better replacement?
412 * Ho-hum... In principle, we might treat that as umount + switch
413 * to rootfs. GC would eventually take care of the old vfsmount.
414 * Actually it makes sense, especially if rootfs would contain a
415 * /reboot - static binary that would close all descriptors and
416 * call reboot(9). Then init(8) could umount root and exec /reboot.
417 */
418 if (mnt == current->fs->rootmnt && !(flags & MNT_DETACH)) {
419 /*
420 * Special case for "unmounting" root ...
421 * we just try to remount it readonly.
422 */
423 down_write(&sb->s_umount);
424 if (!(sb->s_flags & MS_RDONLY)) {
425 lock_kernel();
426 DQUOT_OFF(sb);
427 retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
428 unlock_kernel();
429 }
430 up_write(&sb->s_umount);
431 return retval;
432 }
433
434 down_write(&current->namespace->sem);
435 spin_lock(&vfsmount_lock);
436
437 if (atomic_read(&sb->s_active) == 1) {
438 /* last instance - try to be smart */
439 spin_unlock(&vfsmount_lock);
440 lock_kernel();
441 DQUOT_OFF(sb);
442 acct_auto_close(sb);
443 unlock_kernel();
444 security_sb_umount_close(mnt);
445 spin_lock(&vfsmount_lock);
446 }
447 retval = -EBUSY;
448 if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) {
449 if (!list_empty(&mnt->mnt_list))
450 umount_tree(mnt);
451 retval = 0;
452 }
453 spin_unlock(&vfsmount_lock);
454 if (retval)
455 security_sb_umount_busy(mnt);
456 up_write(&current->namespace->sem);
457 return retval;
458}
459
460/*
461 * Now umount can handle mount points as well as block devices.
462 * This is important for filesystems which use unnamed block devices.
463 *
464 * We now support a flag for forced unmount like the other 'big iron'
465 * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
466 */
467
468asmlinkage long sys_umount(char __user * name, int flags)
469{
470 struct nameidata nd;
471 int retval;
472
473 retval = __user_walk(name, LOOKUP_FOLLOW, &nd);
474 if (retval)
475 goto out;
476 retval = -EINVAL;
477 if (nd.dentry != nd.mnt->mnt_root)
478 goto dput_and_out;
479 if (!check_mnt(nd.mnt))
480 goto dput_and_out;
481
482 retval = -EPERM;
483 if (!capable(CAP_SYS_ADMIN))
484 goto dput_and_out;
485
486 retval = do_umount(nd.mnt, flags);
487dput_and_out:
488 path_release_on_umount(&nd);
489out:
490 return retval;
491}
492
493#ifdef __ARCH_WANT_SYS_OLDUMOUNT
494
495/*
496 * The 2.0 compatible umount. No flags.
497 */
498
499asmlinkage long sys_oldumount(char __user * name)
500{
501 return sys_umount(name,0);
502}
503
504#endif
505
506static int mount_is_safe(struct nameidata *nd)
507{
508 if (capable(CAP_SYS_ADMIN))
509 return 0;
510 return -EPERM;
511#ifdef notyet
512 if (S_ISLNK(nd->dentry->d_inode->i_mode))
513 return -EPERM;
514 if (nd->dentry->d_inode->i_mode & S_ISVTX) {
515 if (current->uid != nd->dentry->d_inode->i_uid)
516 return -EPERM;
517 }
518 if (permission(nd->dentry->d_inode, MAY_WRITE, nd))
519 return -EPERM;
520 return 0;
521#endif
522}
523
524static int
525lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
526{
527 while (1) {
528 if (d == dentry)
529 return 1;
530 if (d == NULL || d == d->d_parent)
531 return 0;
532 d = d->d_parent;
533 }
534}
535
536static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
537{
538 struct vfsmount *res, *p, *q, *r, *s;
539 struct list_head *h;
540 struct nameidata nd;
541
542 res = q = clone_mnt(mnt, dentry);
543 if (!q)
544 goto Enomem;
545 q->mnt_mountpoint = mnt->mnt_mountpoint;
546
547 p = mnt;
548 for (h = mnt->mnt_mounts.next; h != &mnt->mnt_mounts; h = h->next) {
549 r = list_entry(h, struct vfsmount, mnt_child);
550 if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry))
551 continue;
552
553 for (s = r; s; s = next_mnt(s, r)) {
554 while (p != s->mnt_parent) {
555 p = p->mnt_parent;
556 q = q->mnt_parent;
557 }
558 p = s;
559 nd.mnt = q;
560 nd.dentry = p->mnt_mountpoint;
561 q = clone_mnt(p, p->mnt_root);
562 if (!q)
563 goto Enomem;
564 spin_lock(&vfsmount_lock);
565 list_add_tail(&q->mnt_list, &res->mnt_list);
566 attach_mnt(q, &nd);
567 spin_unlock(&vfsmount_lock);
568 }
569 }
570 return res;
571 Enomem:
572 if (res) {
573 spin_lock(&vfsmount_lock);
574 umount_tree(res);
575 spin_unlock(&vfsmount_lock);
576 }
577 return NULL;
578}
579
580static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
581{
582 int err;
583 if (mnt->mnt_sb->s_flags & MS_NOUSER)
584 return -EINVAL;
585
586 if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
587 S_ISDIR(mnt->mnt_root->d_inode->i_mode))
588 return -ENOTDIR;
589
590 err = -ENOENT;
591 down(&nd->dentry->d_inode->i_sem);
592 if (IS_DEADDIR(nd->dentry->d_inode))
593 goto out_unlock;
594
595 err = security_sb_check_sb(mnt, nd);
596 if (err)
597 goto out_unlock;
598
599 err = -ENOENT;
600 spin_lock(&vfsmount_lock);
601 if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) {
602 struct list_head head;
603
604 attach_mnt(mnt, nd);
605 list_add_tail(&head, &mnt->mnt_list);
606 list_splice(&head, current->namespace->list.prev);
607 mntget(mnt);
608 err = 0;
609 }
610 spin_unlock(&vfsmount_lock);
611out_unlock:
612 up(&nd->dentry->d_inode->i_sem);
613 if (!err)
614 security_sb_post_addmount(mnt, nd);
615 return err;
616}
617
618/*
619 * do loopback mount.
620 */
621static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
622{
623 struct nameidata old_nd;
624 struct vfsmount *mnt = NULL;
625 int err = mount_is_safe(nd);
626 if (err)
627 return err;
628 if (!old_name || !*old_name)
629 return -EINVAL;
630 err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd);
631 if (err)
632 return err;
633
634 down_write(&current->namespace->sem);
635 err = -EINVAL;
636 if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) {
637 err = -ENOMEM;
638 if (recurse)
639 mnt = copy_tree(old_nd.mnt, old_nd.dentry);
640 else
641 mnt = clone_mnt(old_nd.mnt, old_nd.dentry);
642 }
643
644 if (mnt) {
645 /* stop bind mounts from expiring */
646 spin_lock(&vfsmount_lock);
647 list_del_init(&mnt->mnt_fslink);
648 spin_unlock(&vfsmount_lock);
649
650 err = graft_tree(mnt, nd);
651 if (err) {
652 spin_lock(&vfsmount_lock);
653 umount_tree(mnt);
654 spin_unlock(&vfsmount_lock);
655 } else
656 mntput(mnt);
657 }
658
659 up_write(&current->namespace->sem);
660 path_release(&old_nd);
661 return err;
662}
663
664/*
665 * change filesystem flags. dir should be a physical root of filesystem.
666 * If you've mounted a non-root directory somewhere and want to do remount
667 * on it - tough luck.
668 */
669
670static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
671 void *data)
672{
673 int err;
674 struct super_block * sb = nd->mnt->mnt_sb;
675
676 if (!capable(CAP_SYS_ADMIN))
677 return -EPERM;
678
679 if (!check_mnt(nd->mnt))
680 return -EINVAL;
681
682 if (nd->dentry != nd->mnt->mnt_root)
683 return -EINVAL;
684
685 down_write(&sb->s_umount);
686 err = do_remount_sb(sb, flags, data, 0);
687 if (!err)
688 nd->mnt->mnt_flags=mnt_flags;
689 up_write(&sb->s_umount);
690 if (!err)
691 security_sb_post_remount(nd->mnt, flags, data);
692 return err;
693}
694
695static int do_move_mount(struct nameidata *nd, char *old_name)
696{
697 struct nameidata old_nd, parent_nd;
698 struct vfsmount *p;
699 int err = 0;
700 if (!capable(CAP_SYS_ADMIN))
701 return -EPERM;
702 if (!old_name || !*old_name)
703 return -EINVAL;
704 err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd);
705 if (err)
706 return err;
707
708 down_write(&current->namespace->sem);
709 while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
710 ;
711 err = -EINVAL;
712 if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
713 goto out;
714
715 err = -ENOENT;
716 down(&nd->dentry->d_inode->i_sem);
717 if (IS_DEADDIR(nd->dentry->d_inode))
718 goto out1;
719
720 spin_lock(&vfsmount_lock);
721 if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry))
722 goto out2;
723
724 err = -EINVAL;
725 if (old_nd.dentry != old_nd.mnt->mnt_root)
726 goto out2;
727
728 if (old_nd.mnt == old_nd.mnt->mnt_parent)
729 goto out2;
730
731 if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
732 S_ISDIR(old_nd.dentry->d_inode->i_mode))
733 goto out2;
734
735 err = -ELOOP;
736 for (p = nd->mnt; p->mnt_parent!=p; p = p->mnt_parent)
737 if (p == old_nd.mnt)
738 goto out2;
739 err = 0;
740
741 detach_mnt(old_nd.mnt, &parent_nd);
742 attach_mnt(old_nd.mnt, nd);
743
744 /* if the mount is moved, it should no longer be expire
745 * automatically */
746 list_del_init(&old_nd.mnt->mnt_fslink);
747out2:
748 spin_unlock(&vfsmount_lock);
749out1:
750 up(&nd->dentry->d_inode->i_sem);
751out:
752 up_write(&current->namespace->sem);
753 if (!err)
754 path_release(&parent_nd);
755 path_release(&old_nd);
756 return err;
757}
758
759/*
760 * create a new mount for userspace and request it to be added into the
761 * namespace's tree
762 */
763static int do_new_mount(struct nameidata *nd, char *type, int flags,
764 int mnt_flags, char *name, void *data)
765{
766 struct vfsmount *mnt;
767
768 if (!type || !memchr(type, 0, PAGE_SIZE))
769 return -EINVAL;
770
771 /* we need capabilities... */
772 if (!capable(CAP_SYS_ADMIN))
773 return -EPERM;
774
775 mnt = do_kern_mount(type, flags, name, data);
776 if (IS_ERR(mnt))
777 return PTR_ERR(mnt);
778
779 return do_add_mount(mnt, nd, mnt_flags, NULL);
780}
781
782/*
783 * add a mount into a namespace's mount tree
784 * - provide the option of adding the new mount to an expiration list
785 */
786int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
787 int mnt_flags, struct list_head *fslist)
788{
789 int err;
790
791 down_write(&current->namespace->sem);
792 /* Something was mounted here while we slept */
793 while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
794 ;
795 err = -EINVAL;
796 if (!check_mnt(nd->mnt))
797 goto unlock;
798
799 /* Refuse the same filesystem on the same mount point */
800 err = -EBUSY;
801 if (nd->mnt->mnt_sb == newmnt->mnt_sb &&
802 nd->mnt->mnt_root == nd->dentry)
803 goto unlock;
804
805 err = -EINVAL;
806 if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))
807 goto unlock;
808
809 newmnt->mnt_flags = mnt_flags;
810 err = graft_tree(newmnt, nd);
811
812 if (err == 0 && fslist) {
813 /* add to the specified expiration list */
814 spin_lock(&vfsmount_lock);
815 list_add_tail(&newmnt->mnt_fslink, fslist);
816 spin_unlock(&vfsmount_lock);
817 }
818
819unlock:
820 up_write(&current->namespace->sem);
821 mntput(newmnt);
822 return err;
823}
824
825EXPORT_SYMBOL_GPL(do_add_mount);
826
827/*
828 * process a list of expirable mountpoints with the intent of discarding any
829 * mountpoints that aren't in use and haven't been touched since last we came
830 * here
831 */
832void mark_mounts_for_expiry(struct list_head *mounts)
833{
834 struct namespace *namespace;
835 struct vfsmount *mnt, *next;
836 LIST_HEAD(graveyard);
837
838 if (list_empty(mounts))
839 return;
840
841 spin_lock(&vfsmount_lock);
842
843 /* extract from the expiration list every vfsmount that matches the
844 * following criteria:
845 * - only referenced by its parent vfsmount
846 * - still marked for expiry (marked on the last call here; marks are
847 * cleared by mntput())
848 */
849 list_for_each_entry_safe(mnt, next, mounts, mnt_fslink) {
850 if (!xchg(&mnt->mnt_expiry_mark, 1) ||
851 atomic_read(&mnt->mnt_count) != 1)
852 continue;
853
854 mntget(mnt);
855 list_move(&mnt->mnt_fslink, &graveyard);
856 }
857
858 /*
859 * go through the vfsmounts we've just consigned to the graveyard to
860 * - check that they're still dead
861 * - delete the vfsmount from the appropriate namespace under lock
862 * - dispose of the corpse
863 */
864 while (!list_empty(&graveyard)) {
865 mnt = list_entry(graveyard.next, struct vfsmount, mnt_fslink);
866 list_del_init(&mnt->mnt_fslink);
867
868 /* don't do anything if the namespace is dead - all the
869 * vfsmounts from it are going away anyway */
870 namespace = mnt->mnt_namespace;
871 if (!namespace || atomic_read(&namespace->count) <= 0)
872 continue;
873 get_namespace(namespace);
874
875 spin_unlock(&vfsmount_lock);
876 down_write(&namespace->sem);
877 spin_lock(&vfsmount_lock);
878
879 /* check that it is still dead: the count should now be 2 - as
880 * contributed by the vfsmount parent and the mntget above */
881 if (atomic_read(&mnt->mnt_count) == 2) {
882 struct vfsmount *xdmnt;
883 struct dentry *xdentry;
884
885 /* delete from the namespace */
886 list_del_init(&mnt->mnt_list);
887 list_del_init(&mnt->mnt_child);
888 list_del_init(&mnt->mnt_hash);
889 mnt->mnt_mountpoint->d_mounted--;
890
891 xdentry = mnt->mnt_mountpoint;
892 mnt->mnt_mountpoint = mnt->mnt_root;
893 xdmnt = mnt->mnt_parent;
894 mnt->mnt_parent = mnt;
895
896 spin_unlock(&vfsmount_lock);
897
898 mntput(xdmnt);
899 dput(xdentry);
900
901 /* now lay it to rest if this was the last ref on the
902 * superblock */
903 if (atomic_read(&mnt->mnt_sb->s_active) == 1) {
904 /* last instance - try to be smart */
905 lock_kernel();
906 DQUOT_OFF(mnt->mnt_sb);
907 acct_auto_close(mnt->mnt_sb);
908 unlock_kernel();
909 }
910
911 mntput(mnt);
912 } else {
913 /* someone brought it back to life whilst we didn't
914 * have any locks held so return it to the expiration
915 * list */
916 list_add_tail(&mnt->mnt_fslink, mounts);
917 spin_unlock(&vfsmount_lock);
918 }
919
920 up_write(&namespace->sem);
921
922 mntput(mnt);
923 put_namespace(namespace);
924
925 spin_lock(&vfsmount_lock);
926 }
927
928 spin_unlock(&vfsmount_lock);
929}
930
931EXPORT_SYMBOL_GPL(mark_mounts_for_expiry);
932
933/*
934 * Some copy_from_user() implementations do not return the exact number of
935 * bytes remaining to copy on a fault. But copy_mount_options() requires that.
936 * Note that this function differs from copy_from_user() in that it will oops
937 * on bad values of `to', rather than returning a short copy.
938 */
939static long
940exact_copy_from_user(void *to, const void __user *from, unsigned long n)
941{
942 char *t = to;
943 const char __user *f = from;
944 char c;
945
946 if (!access_ok(VERIFY_READ, from, n))
947 return n;
948
949 while (n) {
950 if (__get_user(c, f)) {
951 memset(t, 0, n);
952 break;
953 }
954 *t++ = c;
955 f++;
956 n--;
957 }
958 return n;
959}
960
961int copy_mount_options(const void __user *data, unsigned long *where)
962{
963 int i;
964 unsigned long page;
965 unsigned long size;
966
967 *where = 0;
968 if (!data)
969 return 0;
970
971 if (!(page = __get_free_page(GFP_KERNEL)))
972 return -ENOMEM;
973
974 /* We only care that *some* data at the address the user
975 * gave us is valid. Just in case, we'll zero
976 * the remainder of the page.
977 */
978 /* copy_from_user cannot cross TASK_SIZE ! */
979 size = TASK_SIZE - (unsigned long)data;
980 if (size > PAGE_SIZE)
981 size = PAGE_SIZE;
982
983 i = size - exact_copy_from_user((void *)page, data, size);
984 if (!i) {
985 free_page(page);
986 return -EFAULT;
987 }
988 if (i != PAGE_SIZE)
989 memset((char *)page + i, 0, PAGE_SIZE - i);
990 *where = page;
991 return 0;
992}
993
994/*
995 * Flags is a 32-bit value that allows up to 31 non-fs dependent flags to
996 * be given to the mount() call (ie: read-only, no-dev, no-suid etc).
997 *
998 * data is a (void *) that can point to any structure up to
999 * PAGE_SIZE-1 bytes, which can contain arbitrary fs-dependent
1000 * information (or be NULL).
1001 *
1002 * Pre-0.97 versions of mount() didn't have a flags word.
1003 * When the flags word was introduced its top half was required
1004 * to have the magic value 0xC0ED, and this remained so until 2.4.0-test9.
1005 * Therefore, if this magic number is present, it carries no information
1006 * and must be discarded.
1007 */
1008long do_mount(char * dev_name, char * dir_name, char *type_page,
1009 unsigned long flags, void *data_page)
1010{
1011 struct nameidata nd;
1012 int retval = 0;
1013 int mnt_flags = 0;
1014
1015 /* Discard magic */
1016 if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
1017 flags &= ~MS_MGC_MSK;
1018
1019 /* Basic sanity checks */
1020
1021 if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE))
1022 return -EINVAL;
1023 if (dev_name && !memchr(dev_name, 0, PAGE_SIZE))
1024 return -EINVAL;
1025
1026 if (data_page)
1027 ((char *)data_page)[PAGE_SIZE - 1] = 0;
1028
1029 /* Separate the per-mountpoint flags */
1030 if (flags & MS_NOSUID)
1031 mnt_flags |= MNT_NOSUID;
1032 if (flags & MS_NODEV)
1033 mnt_flags |= MNT_NODEV;
1034 if (flags & MS_NOEXEC)
1035 mnt_flags |= MNT_NOEXEC;
1036 flags &= ~(MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_ACTIVE);
1037
1038 /* ... and get the mountpoint */
1039 retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
1040 if (retval)
1041 return retval;
1042
1043 retval = security_sb_mount(dev_name, &nd, type_page, flags, data_page);
1044 if (retval)
1045 goto dput_out;
1046
1047 if (flags & MS_REMOUNT)
1048 retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags,
1049 data_page);
1050 else if (flags & MS_BIND)
1051 retval = do_loopback(&nd, dev_name, flags & MS_REC);
1052 else if (flags & MS_MOVE)
1053 retval = do_move_mount(&nd, dev_name);
1054 else
1055 retval = do_new_mount(&nd, type_page, flags, mnt_flags,
1056 dev_name, data_page);
1057dput_out:
1058 path_release(&nd);
1059 return retval;
1060}
1061
1062int copy_namespace(int flags, struct task_struct *tsk)
1063{
1064 struct namespace *namespace = tsk->namespace;
1065 struct namespace *new_ns;
1066 struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
1067 struct fs_struct *fs = tsk->fs;
1068 struct vfsmount *p, *q;
1069
1070 if (!namespace)
1071 return 0;
1072
1073 get_namespace(namespace);
1074
1075 if (!(flags & CLONE_NEWNS))
1076 return 0;
1077
1078 if (!capable(CAP_SYS_ADMIN)) {
1079 put_namespace(namespace);
1080 return -EPERM;
1081 }
1082
1083 new_ns = kmalloc(sizeof(struct namespace), GFP_KERNEL);
1084 if (!new_ns)
1085 goto out;
1086
1087 atomic_set(&new_ns->count, 1);
1088 init_rwsem(&new_ns->sem);
1089 INIT_LIST_HEAD(&new_ns->list);
1090
1091 down_write(&tsk->namespace->sem);
1092 /* First pass: copy the tree topology */
1093 new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root);
1094 if (!new_ns->root) {
1095 up_write(&tsk->namespace->sem);
1096 kfree(new_ns);
1097 goto out;
1098 }
1099 spin_lock(&vfsmount_lock);
1100 list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
1101 spin_unlock(&vfsmount_lock);
1102
1103 /*
1104 * Second pass: switch the tsk->fs->* elements and mark new vfsmounts
1105 * as belonging to new namespace. We have already acquired a private
1106 * fs_struct, so tsk->fs->lock is not needed.
1107 */
1108 p = namespace->root;
1109 q = new_ns->root;
1110 while (p) {
1111 q->mnt_namespace = new_ns;
1112 if (fs) {
1113 if (p == fs->rootmnt) {
1114 rootmnt = p;
1115 fs->rootmnt = mntget(q);
1116 }
1117 if (p == fs->pwdmnt) {
1118 pwdmnt = p;
1119 fs->pwdmnt = mntget(q);
1120 }
1121 if (p == fs->altrootmnt) {
1122 altrootmnt = p;
1123 fs->altrootmnt = mntget(q);
1124 }
1125 }
1126 p = next_mnt(p, namespace->root);
1127 q = next_mnt(q, new_ns->root);
1128 }
1129 up_write(&tsk->namespace->sem);
1130
1131 tsk->namespace = new_ns;
1132
1133 if (rootmnt)
1134 mntput(rootmnt);
1135 if (pwdmnt)
1136 mntput(pwdmnt);
1137 if (altrootmnt)
1138 mntput(altrootmnt);
1139
1140 put_namespace(namespace);
1141 return 0;
1142
1143out:
1144 put_namespace(namespace);
1145 return -ENOMEM;
1146}
1147
1148asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
1149 char __user * type, unsigned long flags,
1150 void __user * data)
1151{
1152 int retval;
1153 unsigned long data_page;
1154 unsigned long type_page;
1155 unsigned long dev_page;
1156 char *dir_page;
1157
1158 retval = copy_mount_options (type, &type_page);
1159 if (retval < 0)
1160 return retval;
1161
1162 dir_page = getname(dir_name);
1163 retval = PTR_ERR(dir_page);
1164 if (IS_ERR(dir_page))
1165 goto out1;
1166
1167 retval = copy_mount_options (dev_name, &dev_page);
1168 if (retval < 0)
1169 goto out2;
1170
1171 retval = copy_mount_options (data, &data_page);
1172 if (retval < 0)
1173 goto out3;
1174
1175 lock_kernel();
1176 retval = do_mount((char*)dev_page, dir_page, (char*)type_page,
1177 flags, (void*)data_page);
1178 unlock_kernel();
1179 free_page(data_page);
1180
1181out3:
1182 free_page(dev_page);
1183out2:
1184 putname(dir_page);
1185out1:
1186 free_page(type_page);
1187 return retval;
1188}
1189
1190/*
1191 * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
1192 * It can block. Requires the big lock held.
1193 */
1194void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
1195 struct dentry *dentry)
1196{
1197 struct dentry *old_root;
1198 struct vfsmount *old_rootmnt;
1199 write_lock(&fs->lock);
1200 old_root = fs->root;
1201 old_rootmnt = fs->rootmnt;
1202 fs->rootmnt = mntget(mnt);
1203 fs->root = dget(dentry);
1204 write_unlock(&fs->lock);
1205 if (old_root) {
1206 dput(old_root);
1207 mntput(old_rootmnt);
1208 }
1209}
1210
1211/*
1212 * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
1213 * It can block. Requires the big lock held.
1214 */
1215void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
1216 struct dentry *dentry)
1217{
1218 struct dentry *old_pwd;
1219 struct vfsmount *old_pwdmnt;
1220
1221 write_lock(&fs->lock);
1222 old_pwd = fs->pwd;
1223 old_pwdmnt = fs->pwdmnt;
1224 fs->pwdmnt = mntget(mnt);
1225 fs->pwd = dget(dentry);
1226 write_unlock(&fs->lock);
1227
1228 if (old_pwd) {
1229 dput(old_pwd);
1230 mntput(old_pwdmnt);
1231 }
1232}
1233
1234static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
1235{
1236 struct task_struct *g, *p;
1237 struct fs_struct *fs;
1238
1239 read_lock(&tasklist_lock);
1240 do_each_thread(g, p) {
1241 task_lock(p);
1242 fs = p->fs;
1243 if (fs) {
1244 atomic_inc(&fs->count);
1245 task_unlock(p);
1246 if (fs->root==old_nd->dentry&&fs->rootmnt==old_nd->mnt)
1247 set_fs_root(fs, new_nd->mnt, new_nd->dentry);
1248 if (fs->pwd==old_nd->dentry&&fs->pwdmnt==old_nd->mnt)
1249 set_fs_pwd(fs, new_nd->mnt, new_nd->dentry);
1250 put_fs_struct(fs);
1251 } else
1252 task_unlock(p);
1253 } while_each_thread(g, p);
1254 read_unlock(&tasklist_lock);
1255}
1256
1257/*
1258 * pivot_root Semantics:
1259 * Moves the root file system of the current process to the directory put_old,
1260 * makes new_root as the new root file system of the current process, and sets
1261 * root/cwd of all processes which had them on the current root to new_root.
1262 *
1263 * Restrictions:
1264 * The new_root and put_old must be directories, and must not be on the
1265 * same file system as the current process root. The put_old must be
1266 * underneath new_root, i.e. adding a non-zero number of /.. to the string
1267 * pointed to by put_old must yield the same directory as new_root. No other
1268 * file system may be mounted on put_old. After all, new_root is a mountpoint.
1269 *
1270 * Notes:
1271 * - we don't move root/cwd if they are not at the root (reason: if something
1272 * cared enough to change them, it's probably wrong to force them elsewhere)
1273 * - it's okay to pick a root that isn't the root of a file system, e.g.
1274 * /nfs/my_root where /nfs is the mount point. It must be a mountpoint,
1275 * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
1276 * first.
1277 */
1278
1279asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *put_old)
1280{
1281 struct vfsmount *tmp;
1282 struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd;
1283 int error;
1284
1285 if (!capable(CAP_SYS_ADMIN))
1286 return -EPERM;
1287
1288 lock_kernel();
1289
1290 error = __user_walk(new_root, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &new_nd);
1291 if (error)
1292 goto out0;
1293 error = -EINVAL;
1294 if (!check_mnt(new_nd.mnt))
1295 goto out1;
1296
1297 error = __user_walk(put_old, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &old_nd);
1298 if (error)
1299 goto out1;
1300
1301 error = security_sb_pivotroot(&old_nd, &new_nd);
1302 if (error) {
1303 path_release(&old_nd);
1304 goto out1;
1305 }
1306
1307 read_lock(&current->fs->lock);
1308 user_nd.mnt = mntget(current->fs->rootmnt);
1309 user_nd.dentry = dget(current->fs->root);
1310 read_unlock(&current->fs->lock);
1311 down_write(&current->namespace->sem);
1312 down(&old_nd.dentry->d_inode->i_sem);
1313 error = -EINVAL;
1314 if (!check_mnt(user_nd.mnt))
1315 goto out2;
1316 error = -ENOENT;
1317 if (IS_DEADDIR(new_nd.dentry->d_inode))
1318 goto out2;
1319 if (d_unhashed(new_nd.dentry) && !IS_ROOT(new_nd.dentry))
1320 goto out2;
1321 if (d_unhashed(old_nd.dentry) && !IS_ROOT(old_nd.dentry))
1322 goto out2;
1323 error = -EBUSY;
1324 if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt)
1325 goto out2; /* loop, on the same file system */
1326 error = -EINVAL;
1327 if (user_nd.mnt->mnt_root != user_nd.dentry)
1328 goto out2; /* not a mountpoint */
1329 if (new_nd.mnt->mnt_root != new_nd.dentry)
1330 goto out2; /* not a mountpoint */
1331 tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
1332 spin_lock(&vfsmount_lock);
1333 if (tmp != new_nd.mnt) {
1334 for (;;) {
1335 if (tmp->mnt_parent == tmp)
1336 goto out3; /* already mounted on put_old */
1337 if (tmp->mnt_parent == new_nd.mnt)
1338 break;
1339 tmp = tmp->mnt_parent;
1340 }
1341 if (!is_subdir(tmp->mnt_mountpoint, new_nd.dentry))
1342 goto out3;
1343 } else if (!is_subdir(old_nd.dentry, new_nd.dentry))
1344 goto out3;
1345 detach_mnt(new_nd.mnt, &parent_nd);
1346 detach_mnt(user_nd.mnt, &root_parent);
1347 attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */
1348 attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
1349 spin_unlock(&vfsmount_lock);
1350 chroot_fs_refs(&user_nd, &new_nd);
1351 security_sb_post_pivotroot(&user_nd, &new_nd);
1352 error = 0;
1353 path_release(&root_parent);
1354 path_release(&parent_nd);
1355out2:
1356 up(&old_nd.dentry->d_inode->i_sem);
1357 up_write(&current->namespace->sem);
1358 path_release(&user_nd);
1359 path_release(&old_nd);
1360out1:
1361 path_release(&new_nd);
1362out0:
1363 unlock_kernel();
1364 return error;
1365out3:
1366 spin_unlock(&vfsmount_lock);
1367 goto out2;
1368}
1369
1370static void __init init_mount_tree(void)
1371{
1372 struct vfsmount *mnt;
1373 struct namespace *namespace;
1374 struct task_struct *g, *p;
1375
1376 mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
1377 if (IS_ERR(mnt))
1378 panic("Can't create rootfs");
1379 namespace = kmalloc(sizeof(*namespace), GFP_KERNEL);
1380 if (!namespace)
1381 panic("Can't allocate initial namespace");
1382 atomic_set(&namespace->count, 1);
1383 INIT_LIST_HEAD(&namespace->list);
1384 init_rwsem(&namespace->sem);
1385 list_add(&mnt->mnt_list, &namespace->list);
1386 namespace->root = mnt;
1387 mnt->mnt_namespace = namespace;
1388
1389 init_task.namespace = namespace;
1390 read_lock(&tasklist_lock);
1391 do_each_thread(g, p) {
1392 get_namespace(namespace);
1393 p->namespace = namespace;
1394 } while_each_thread(g, p);
1395 read_unlock(&tasklist_lock);
1396
1397 set_fs_pwd(current->fs, namespace->root, namespace->root->mnt_root);
1398 set_fs_root(current->fs, namespace->root, namespace->root->mnt_root);
1399}
1400
1401void __init mnt_init(unsigned long mempages)
1402{
1403 struct list_head *d;
1404 unsigned int nr_hash;
1405 int i;
1406
1407 mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount),
1408 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1409
1410 mount_hashtable = (struct list_head *)
1411 __get_free_page(GFP_ATOMIC);
1412
1413 if (!mount_hashtable)
1414 panic("Failed to allocate mount hash table\n");
1415
1416 /*
1417 * Find the power-of-two list-heads that can fit into the allocation..
1418 * We don't guarantee that "sizeof(struct list_head)" is necessarily
1419 * a power-of-two.
1420 */
1421 nr_hash = PAGE_SIZE / sizeof(struct list_head);
1422 hash_bits = 0;
1423 do {
1424 hash_bits++;
1425 } while ((nr_hash >> hash_bits) != 0);
1426 hash_bits--;
1427
1428 /*
1429 * Re-calculate the actual number of entries and the mask
1430 * from the number of bits we can fit.
1431 */
1432 nr_hash = 1UL << hash_bits;
1433 hash_mask = nr_hash-1;
1434
1435 printk("Mount-cache hash table entries: %d\n", nr_hash);
1436
1437 /* And initialize the newly allocated array */
1438 d = mount_hashtable;
1439 i = nr_hash;
1440 do {
1441 INIT_LIST_HEAD(d);
1442 d++;
1443 i--;
1444 } while (i);
1445 sysfs_init();
1446 init_rootfs();
1447 init_mount_tree();
1448}
1449
1450void __put_namespace(struct namespace *namespace)
1451{
1452 struct vfsmount *mnt;
1453
1454 down_write(&namespace->sem);
1455 spin_lock(&vfsmount_lock);
1456
1457 list_for_each_entry(mnt, &namespace->list, mnt_list) {
1458 mnt->mnt_namespace = NULL;
1459 }
1460
1461 umount_tree(namespace->root);
1462 spin_unlock(&vfsmount_lock);
1463 up_write(&namespace->sem);
1464 kfree(namespace);
1465}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-25 13:37:09 -0500