*/
#include <linux/config.h>
+#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/quotaops.h>
#include <linux/acct.h>
+#include <linux/capability.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/namespace.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/mount.h>
+#include <linux/vserver/namespace.h>
+#include <linux/vserver/xid.h>
#include <asm/uaccess.h>
+#include <asm/unistd.h>
+#include "pnode.h"
extern int __init init_rootfs(void);
#endif
/* spinlock for vfsmount related operations, inplace of dcache_lock */
-spinlock_t vfsmount_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
-static struct list_head *mount_hashtable;
-static int hash_mask, hash_bits;
-static kmem_cache_t *mnt_cache;
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+
+static int event;
+
+static struct list_head *mount_hashtable __read_mostly;
+static int hash_mask __read_mostly, hash_bits __read_mostly;
+static kmem_cache_t *mnt_cache __read_mostly;
+static struct rw_semaphore namespace_sem;
+
+/* /sys/fs */
+decl_subsys(fs, NULL, NULL);
+EXPORT_SYMBOL_GPL(fs_subsys);
static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
{
- unsigned long tmp = ((unsigned long) mnt / L1_CACHE_BYTES);
- tmp += ((unsigned long) dentry / L1_CACHE_BYTES);
+ unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
+ tmp += ((unsigned long)dentry / L1_CACHE_BYTES);
tmp = tmp + (tmp >> hash_bits);
return tmp & hash_mask;
}
struct vfsmount *alloc_vfsmnt(const char *name)
{
- struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
+ struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
if (mnt) {
memset(mnt, 0, sizeof(struct vfsmount));
- atomic_set(&mnt->mnt_count,1);
+ atomic_set(&mnt->mnt_count, 1);
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
INIT_LIST_HEAD(&mnt->mnt_mounts);
INIT_LIST_HEAD(&mnt->mnt_list);
+ INIT_LIST_HEAD(&mnt->mnt_expire);
+ INIT_LIST_HEAD(&mnt->mnt_share);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ INIT_LIST_HEAD(&mnt->mnt_slave);
if (name) {
- int size = strlen(name)+1;
+ int size = strlen(name) + 1;
char *newname = kmalloc(size, GFP_KERNEL);
if (newname) {
memcpy(newname, name, size);
}
/*
- * Now, lookup_mnt increments the ref count before returning
- * the vfsmount struct.
+ * find the first or last mount at @dentry on vfsmount @mnt depending on
+ * @dir. If @dir is set return the first mount else return the last mount.
*/
-struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
+ int dir)
{
- struct list_head * head = mount_hashtable + hash(mnt, dentry);
- struct list_head * tmp = head;
+ struct list_head *head = mount_hashtable + hash(mnt, dentry);
+ struct list_head *tmp = head;
struct vfsmount *p, *found = NULL;
- spin_lock(&vfsmount_lock);
for (;;) {
- tmp = tmp->next;
+ tmp = dir ? tmp->next : tmp->prev;
p = NULL;
if (tmp == head)
break;
p = list_entry(tmp, struct vfsmount, mnt_hash);
if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) {
- found = mntget(p);
+ found = p;
break;
}
}
- spin_unlock(&vfsmount_lock);
return found;
}
-EXPORT_SYMBOL(lookup_mnt);
-
-static int check_mnt(struct vfsmount *mnt)
+/*
+ * lookup_mnt increments the ref count before returning
+ * the vfsmount struct.
+ */
+struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
{
+ struct vfsmount *child_mnt;
spin_lock(&vfsmount_lock);
- while (mnt->mnt_parent != mnt)
- mnt = mnt->mnt_parent;
+ if ((child_mnt = __lookup_mnt(mnt, dentry, 1)))
+ mntget(child_mnt);
spin_unlock(&vfsmount_lock);
- return mnt == current->namespace->root;
+ return child_mnt;
+}
+
+static inline int check_mnt(struct vfsmount *mnt)
+{
+ return mnt->mnt_namespace == current->namespace;
+}
+
+static void touch_namespace(struct namespace *ns)
+{
+ if (ns) {
+ ns->event = ++event;
+ wake_up_interruptible(&ns->poll);
+ }
+}
+
+static void __touch_namespace(struct namespace *ns)
+{
+ if (ns && ns->event != event) {
+ ns->event = event;
+ wake_up_interruptible(&ns->poll);
+ }
}
static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
old_nd->dentry->d_mounted--;
}
+void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
+ struct vfsmount *child_mnt)
+{
+ child_mnt->mnt_parent = mntget(mnt);
+ child_mnt->mnt_mountpoint = dget(dentry);
+ dentry->d_mounted++;
+}
+
static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
{
- mnt->mnt_parent = mntget(nd->mnt);
- mnt->mnt_mountpoint = dget(nd->dentry);
- list_add(&mnt->mnt_hash, mount_hashtable+hash(nd->mnt, nd->dentry));
+ mnt_set_mountpoint(nd->mnt, nd->dentry, mnt);
+ list_add_tail(&mnt->mnt_hash, mount_hashtable +
+ hash(nd->mnt, nd->dentry));
list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts);
- nd->dentry->d_mounted++;
+}
+
+/*
+ * the caller must hold vfsmount_lock
+ */
+static void commit_tree(struct vfsmount *mnt)
+{
+ struct vfsmount *parent = mnt->mnt_parent;
+ struct vfsmount *m;
+ LIST_HEAD(head);
+ struct namespace *n = parent->mnt_namespace;
+
+ BUG_ON(parent == mnt);
+
+ list_add_tail(&head, &mnt->mnt_list);
+ list_for_each_entry(m, &head, mnt_list)
+ m->mnt_namespace = n;
+ list_splice(&head, n->list.prev);
+
+ list_add_tail(&mnt->mnt_hash, mount_hashtable +
+ hash(parent, mnt->mnt_mountpoint));
+ list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
+ touch_namespace(n);
}
static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root)
return list_entry(next, struct vfsmount, mnt_child);
}
-static struct vfsmount *
-clone_mnt(struct vfsmount *old, struct dentry *root)
+static struct vfsmount *skip_mnt_tree(struct vfsmount *p)
+{
+ struct list_head *prev = p->mnt_mounts.prev;
+ while (prev != &p->mnt_mounts) {
+ p = list_entry(prev, struct vfsmount, mnt_child);
+ prev = p->mnt_mounts.prev;
+ }
+ return p;
+}
+
+static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
+ int flag)
{
struct super_block *sb = old->mnt_sb;
struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
mnt->mnt_root = dget(root);
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
+ mnt->mnt_xid = old->mnt_xid;
+
+ if (flag & CL_SLAVE) {
+ list_add(&mnt->mnt_slave, &old->mnt_slave_list);
+ mnt->mnt_master = old;
+ CLEAR_MNT_SHARED(mnt);
+ } else {
+ if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
+ list_add(&mnt->mnt_share, &old->mnt_share);
+ if (IS_MNT_SLAVE(old))
+ list_add(&mnt->mnt_slave, &old->mnt_slave);
+ mnt->mnt_master = old->mnt_master;
+ }
+ if (flag & CL_MAKE_SHARED)
+ set_mnt_shared(mnt);
+
+ /* stick the duplicate mount on the same expiry list
+ * as the original if that was on one */
+ if (flag & CL_EXPIRE) {
+ spin_lock(&vfsmount_lock);
+ if (!list_empty(&old->mnt_expire))
+ list_add(&mnt->mnt_expire, &old->mnt_expire);
+ spin_unlock(&vfsmount_lock);
+ }
}
return mnt;
}
-void __mntput(struct vfsmount *mnt)
+static inline void __mntput(struct vfsmount *mnt)
{
struct super_block *sb = mnt->mnt_sb;
dput(mnt->mnt_root);
deactivate_super(sb);
}
-EXPORT_SYMBOL(__mntput);
+void mntput_no_expire(struct vfsmount *mnt)
+{
+repeat:
+ if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) {
+ if (likely(!mnt->mnt_pinned)) {
+ spin_unlock(&vfsmount_lock);
+ __mntput(mnt);
+ return;
+ }
+ atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count);
+ mnt->mnt_pinned = 0;
+ spin_unlock(&vfsmount_lock);
+ acct_auto_close_mnt(mnt);
+ security_sb_umount_close(mnt);
+ goto repeat;
+ }
+}
+
+EXPORT_SYMBOL(mntput_no_expire);
+
+void mnt_pin(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ mnt->mnt_pinned++;
+ spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL(mnt_pin);
+
+void mnt_unpin(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ if (mnt->mnt_pinned) {
+ atomic_inc(&mnt->mnt_count);
+ mnt->mnt_pinned--;
+ }
+ spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL(mnt_unpin);
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
struct list_head *p;
loff_t l = *pos;
- down_read(&n->sem);
+ down_read(&namespace_sem);
list_for_each(p, &n->list)
if (!l--)
return list_entry(p, struct vfsmount, mnt_list);
struct namespace *n = m->private;
struct list_head *p = ((struct vfsmount *)v)->mnt_list.next;
(*pos)++;
- return p==&n->list ? NULL : list_entry(p, struct vfsmount, mnt_list);
+ return p == &n->list ? NULL : list_entry(p, struct vfsmount, mnt_list);
}
static void m_stop(struct seq_file *m, void *v)
{
- struct namespace *n = m->private;
- up_read(&n->sem);
+ up_read(&namespace_sem);
}
static inline void mangle(struct seq_file *m, const char *s)
seq_escape(m, s, " \t\n\\");
}
+static int mnt_is_reachable(struct vfsmount *mnt)
+{
+ struct vfsmount *root_mnt;
+ struct dentry *root, *point;
+ int ret;
+
+ if (mnt == mnt->mnt_namespace->root)
+ return 1;
+
+ spin_lock(&dcache_lock);
+ root_mnt = current->fs->rootmnt;
+ root = current->fs->root;
+ point = root;
+
+ while ((mnt != mnt->mnt_parent) && (mnt != root_mnt)) {
+ point = mnt->mnt_mountpoint;
+ mnt = mnt->mnt_parent;
+ }
+
+ ret = (mnt == root_mnt) && is_subdir(point, root);
+
+ spin_unlock(&dcache_lock);
+
+ return ret;
+}
+
static int show_vfsmnt(struct seq_file *m, void *v)
{
struct vfsmount *mnt = v;
int err = 0;
static struct proc_fs_info {
- int flag;
- char *str;
+ int s_flag;
+ int mnt_flag;
+ char *set_str;
+ char *unset_str;
} fs_info[] = {
- { MS_SYNCHRONOUS, ",sync" },
- { MS_DIRSYNC, ",dirsync" },
- { MS_MANDLOCK, ",mand" },
- { MS_NOATIME, ",noatime" },
- { MS_NODIRATIME, ",nodiratime" },
- { 0, NULL }
- };
- static struct proc_fs_info mnt_info[] = {
- { MNT_NOSUID, ",nosuid" },
- { MNT_NODEV, ",nodev" },
- { MNT_NOEXEC, ",noexec" },
- { 0, NULL }
+ { MS_RDONLY, MNT_RDONLY, "ro", "rw" },
+ { MS_SYNCHRONOUS, 0, ",sync", NULL },
+ { MS_DIRSYNC, 0, ",dirsync", NULL },
+ { MS_MANDLOCK, 0, ",mand", NULL },
+ { MS_TAGXID, 0, ",tagxid", NULL },
+ { MS_NOATIME, MNT_NOATIME, ",noatime", NULL },
+ { MS_NODIRATIME, MNT_NODIRATIME, ",nodiratime", NULL },
+ { 0, MNT_NOSUID, ",nosuid", NULL },
+ { 0, MNT_NODEV, ",nodev", NULL },
+ { 0, MNT_NOEXEC, ",noexec", NULL },
+ { 0, 0, NULL, NULL }
};
- struct proc_fs_info *fs_infop;
+ struct proc_fs_info *p;
+ unsigned long s_flags = mnt->mnt_sb->s_flags;
+ int mnt_flags = mnt->mnt_flags;
if (vx_flags(VXF_HIDE_MOUNT, 0))
return 0;
+ if (!mnt_is_reachable(mnt))
+ return 0;
- mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
- seq_putc(m, ' ');
- seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
- seq_putc(m, ' ');
- mangle(m, mnt->mnt_sb->s_type->name);
- seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw");
- for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
- if (mnt->mnt_sb->s_flags & fs_infop->flag)
- seq_puts(m, fs_infop->str);
+ if (!vx_check(0, VX_ADMIN|VX_WATCH) &&
+ mnt == current->fs->rootmnt) {
+ seq_puts(m, "/dev/root / ");
+ } else {
+ mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+ seq_putc(m, ' ');
+ seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
+ seq_putc(m, ' ');
}
- for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
- if (mnt->mnt_flags & fs_infop->flag)
- seq_puts(m, fs_infop->str);
+ mangle(m, mnt->mnt_sb->s_type->name);
+ seq_putc(m, ' ');
+ for (p = fs_info; (p->s_flag | p->mnt_flag) ; p++) {
+ if ((s_flags & p->s_flag) || (mnt_flags & p->mnt_flag)) {
+ if (p->set_str)
+ seq_puts(m, p->set_str);
+ } else {
+ if (p->unset_str)
+ seq_puts(m, p->unset_str);
+ }
}
+ if (mnt->mnt_flags & MNT_XID)
+ seq_printf(m, ",xid=%d", mnt->mnt_xid);
if (mnt->mnt_sb->s_op->show_options)
err = mnt->mnt_sb->s_op->show_options(m, mnt);
seq_puts(m, " 0 0\n");
.show = show_vfsmnt
};
-/*
+static int show_vfsstat(struct seq_file *m, void *v)
+{
+ struct vfsmount *mnt = v;
+ int err = 0;
+
+ if (vx_flags(VXF_HIDE_MOUNT, 0))
+ return 0;
+ if (!mnt_is_reachable(mnt) && !vx_check(0, VX_WATCH))
+ return 0;
+
+ if (!vx_check(0, VX_ADMIN|VX_WATCH) &&
+ mnt == current->fs->rootmnt) {
+ seq_puts(m, "device /dev/root mounted on / ");
+ } else {
+ /* device */
+ if (mnt->mnt_devname) {
+ seq_puts(m, "device ");
+ mangle(m, mnt->mnt_devname);
+ } else
+ seq_puts(m, "no device");
+
+ /* mount point */
+ seq_puts(m, " mounted on ");
+ seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
+ seq_putc(m, ' ');
+ }
+
+ /* file system type */
+ seq_puts(m, "with fstype ");
+ mangle(m, mnt->mnt_sb->s_type->name);
+
+ /* optional statistics */
+ if (mnt->mnt_sb->s_op->show_stats) {
+ seq_putc(m, ' ');
+ err = mnt->mnt_sb->s_op->show_stats(m, mnt);
+ }
+
+ seq_putc(m, '\n');
+ return err;
+}
+
+struct seq_operations mountstats_op = {
+ .start = m_start,
+ .next = m_next,
+ .stop = m_stop,
+ .show = show_vfsstat,
+};
+
+/**
+ * may_umount_tree - check if a mount tree is busy
+ * @mnt: root of mount tree
+ *
+ * This is called to check if a tree of mounts has any
+ * open files, pwds, chroots or sub mounts that are
+ * busy.
+ */
+int may_umount_tree(struct vfsmount *mnt)
+{
+ int actual_refs = 0;
+ int minimum_refs = 0;
+ struct vfsmount *p;
+
+ spin_lock(&vfsmount_lock);
+ for (p = mnt; p; p = next_mnt(p, mnt)) {
+ actual_refs += atomic_read(&p->mnt_count);
+ minimum_refs += 2;
+ }
+ spin_unlock(&vfsmount_lock);
+
+ if (actual_refs > minimum_refs)
+ return 0;
+
+ return 1;
+}
+
+EXPORT_SYMBOL(may_umount_tree);
+
+/**
+ * may_umount - check if a mount point is busy
+ * @mnt: root of mount
+ *
+ * This is called to check if a mount point has any
+ * open files, pwds, chroots or sub mounts. If the
+ * mount has sub mounts this will return busy
+ * regardless of whether the sub mounts are busy.
+ *
* Doesn't take quota and stuff into account. IOW, in some cases it will
* give false negatives. The main reason why it's here is that we need
* a non-destructive way to look for easily umountable filesystems.
*/
int may_umount(struct vfsmount *mnt)
{
- if (atomic_read(&mnt->mnt_count) > 2)
- return -EBUSY;
- return 0;
+ int ret = 1;
+ spin_lock(&vfsmount_lock);
+ if (propagate_mount_busy(mnt, 2))
+ ret = 0;
+ spin_unlock(&vfsmount_lock);
+ return ret;
}
EXPORT_SYMBOL(may_umount);
-static inline void __umount_tree(struct vfsmount *mnt, struct list_head *kill)
+void release_mounts(struct list_head *head)
{
- while (!list_empty(kill)) {
- mnt = list_entry(kill->next, struct vfsmount, mnt_list);
- list_del_init(&mnt->mnt_list);
- if (mnt->mnt_parent == mnt) {
- spin_unlock(&vfsmount_lock);
- } else {
- struct nameidata old_nd;
- detach_mnt(mnt, &old_nd);
+ struct vfsmount *mnt;
+ while (!list_empty(head)) {
+ mnt = list_entry(head->next, struct vfsmount, mnt_hash);
+ list_del_init(&mnt->mnt_hash);
+ if (mnt->mnt_parent != mnt) {
+ struct dentry *dentry;
+ struct vfsmount *m;
+ spin_lock(&vfsmount_lock);
+ dentry = mnt->mnt_mountpoint;
+ m = mnt->mnt_parent;
+ mnt->mnt_mountpoint = mnt->mnt_root;
+ mnt->mnt_parent = mnt;
spin_unlock(&vfsmount_lock);
- path_release(&old_nd);
+ dput(dentry);
+ mntput(m);
}
mntput(mnt);
- spin_lock(&vfsmount_lock);
}
}
-void umount_tree(struct vfsmount *mnt)
+void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
{
struct vfsmount *p;
- LIST_HEAD(kill);
for (p = mnt; p; p = next_mnt(p, mnt)) {
- list_del(&p->mnt_list);
- list_add(&p->mnt_list, &kill);
+ list_del(&p->mnt_hash);
+ list_add(&p->mnt_hash, kill);
}
- __umount_tree(mnt, &kill);
-}
-
-void umount_unused(struct vfsmount *mnt, struct fs_struct *fs)
-{
- struct vfsmount *p;
- LIST_HEAD(kill);
- for (p = mnt; p; p = next_mnt(p, mnt)) {
- if (p == fs->rootmnt || p == fs->pwdmnt)
- continue;
- list_del(&p->mnt_list);
- list_add(&p->mnt_list, &kill);
+ if (propagate)
+ propagate_umount(kill);
+
+ list_for_each_entry(p, kill, mnt_hash) {
+ list_del_init(&p->mnt_expire);
+ list_del_init(&p->mnt_list);
+ __touch_namespace(p->mnt_namespace);
+ p->mnt_namespace = NULL;
+ list_del_init(&p->mnt_child);
+ if (p->mnt_parent != p)
+ p->mnt_mountpoint->d_mounted--;
+ change_mnt_propagation(p, MS_PRIVATE);
}
- __umount_tree(mnt, &kill);
}
static int do_umount(struct vfsmount *mnt, int flags)
{
- struct super_block * sb = mnt->mnt_sb;
+ struct super_block *sb = mnt->mnt_sb;
int retval;
+ LIST_HEAD(umount_list);
retval = security_sb_umount(mnt, flags);
if (retval)
return retval;
+ /*
+ * Allow userspace to request a mountpoint be expired rather than
+ * unmounting unconditionally. Unmount only happens if:
+ * (1) the mark is already set (the mark is cleared by mntput())
+ * (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount]
+ */
+ if (flags & MNT_EXPIRE) {
+ if (mnt == current->fs->rootmnt ||
+ flags & (MNT_FORCE | MNT_DETACH))
+ return -EINVAL;
+
+ if (atomic_read(&mnt->mnt_count) != 2)
+ return -EBUSY;
+
+ if (!xchg(&mnt->mnt_expiry_mark, 1))
+ return -EAGAIN;
+ }
+
/*
* If we may have to abort operations to get out of this
* mount, and they will themselves hold resources we must
*/
lock_kernel();
- if( (flags&MNT_FORCE) && sb->s_op->umount_begin)
+ if ((flags & MNT_FORCE) && sb->s_op->umount_begin)
sb->s_op->umount_begin(sb);
unlock_kernel();
down_write(&sb->s_umount);
if (!(sb->s_flags & MS_RDONLY)) {
lock_kernel();
- retval = do_remount_sb(sb, MS_RDONLY, 0, 0);
+ DQUOT_OFF(sb);
+ retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
unlock_kernel();
}
up_write(&sb->s_umount);
return retval;
}
- down_write(¤t->namespace->sem);
+ down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
+ event++;
- if (atomic_read(&sb->s_active) == 1) {
- /* last instance - try to be smart */
- spin_unlock(&vfsmount_lock);
- lock_kernel();
- DQUOT_OFF(sb);
- acct_auto_close(sb);
- unlock_kernel();
- security_sb_umount_close(mnt);
- spin_lock(&vfsmount_lock);
- }
retval = -EBUSY;
- if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) {
+ if (flags & MNT_DETACH || !propagate_mount_busy(mnt, 2)) {
if (!list_empty(&mnt->mnt_list))
- umount_tree(mnt);
+ umount_tree(mnt, 1, &umount_list);
retval = 0;
}
spin_unlock(&vfsmount_lock);
if (retval)
security_sb_umount_busy(mnt);
- up_write(¤t->namespace->sem);
+ up_write(&namespace_sem);
+ release_mounts(&umount_list);
return retval;
}
goto dput_and_out;
retval = -EPERM;
- if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_MOUNT))
+ if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT))
goto dput_and_out;
retval = do_umount(nd.mnt, flags);
dput_and_out:
- path_release(&nd);
+ path_release_on_umount(&nd);
out:
return retval;
}
+#ifdef __ARCH_WANT_SYS_OLDUMOUNT
+
/*
- * The 2.0 compatible umount. No flags.
+ * The 2.0 compatible umount. No flags.
*/
-
asmlinkage long sys_oldumount(char __user * name)
{
- return sys_umount(name,0);
+ return sys_umount(name, 0);
}
+#endif
+
static int mount_is_safe(struct nameidata *nd)
{
- if (capable(CAP_SYS_ADMIN))
- return 0;
- if (vx_ccaps(VXC_SECURE_MOUNT))
+ if (vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT))
return 0;
return -EPERM;
#ifdef notyet
if (current->uid != nd->dentry->d_inode->i_uid)
return -EPERM;
}
- if (permission(nd->dentry->d_inode, MAY_WRITE, nd))
+ if (vfs_permission(nd, MAY_WRITE))
return -EPERM;
return 0;
#endif
}
-static int
-lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
+static int lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
{
while (1) {
if (d == dentry)
}
}
-static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
+ int flag)
{
struct vfsmount *res, *p, *q, *r, *s;
- struct list_head *h;
struct nameidata nd;
- res = q = clone_mnt(mnt, dentry);
+ if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
+ return NULL;
+
+ res = q = clone_mnt(mnt, dentry, flag);
if (!q)
goto Enomem;
q->mnt_mountpoint = mnt->mnt_mountpoint;
p = mnt;
- for (h = mnt->mnt_mounts.next; h != &mnt->mnt_mounts; h = h->next) {
- r = list_entry(h, struct vfsmount, mnt_child);
+ list_for_each_entry(r, &mnt->mnt_mounts, mnt_child) {
if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry))
continue;
for (s = r; s; s = next_mnt(s, r)) {
+ if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(s)) {
+ s = skip_mnt_tree(s);
+ continue;
+ }
while (p != s->mnt_parent) {
p = p->mnt_parent;
q = q->mnt_parent;
p = s;
nd.mnt = q;
nd.dentry = p->mnt_mountpoint;
- q = clone_mnt(p, p->mnt_root);
+ q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
spin_lock(&vfsmount_lock);
}
}
return res;
- Enomem:
+Enomem:
if (res) {
+ LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
- umount_tree(res);
+ umount_tree(res, 0, &umount_list);
spin_unlock(&vfsmount_lock);
+ release_mounts(&umount_list);
}
return NULL;
}
+/*
+ * @source_mnt : mount tree to be attached
+ * @nd : place the mount tree @source_mnt is attached
+ * @parent_nd : if non-null, detach the source_mnt from its parent and
+ * store the parent mount and mountpoint dentry.
+ * (done when source_mnt is moved)
+ *
+ * NOTE: in the table below explains the semantics when a source mount
+ * of a given type is attached to a destination mount of a given type.
+ * ---------------------------------------------------------------------------
+ * | BIND MOUNT OPERATION |
+ * |**************************************************************************
+ * | source-->| shared | private | slave | unbindable |
+ * | dest | | | | |
+ * | | | | | | |
+ * | v | | | | |
+ * |**************************************************************************
+ * | shared | shared (++) | shared (+) | shared(+++)| invalid |
+ * | | | | | |
+ * |non-shared| shared (+) | private | slave (*) | invalid |
+ * ***************************************************************************
+ * A bind operation clones the source mount and mounts the clone on the
+ * destination mount.
+ *
+ * (++) the cloned mount is propagated to all the mounts in the propagation
+ * tree of the destination mount and the cloned mount is added to
+ * the peer group of the source mount.
+ * (+) the cloned mount is created under the destination mount and is marked
+ * as shared. The cloned mount is added to the peer group of the source
+ * mount.
+ * (+++) the mount is propagated to all the mounts in the propagation tree
+ * of the destination mount and the cloned mount is made slave
+ * of the same master as that of the source mount. The cloned mount
+ * is marked as 'shared and slave'.
+ * (*) the cloned mount is made a slave of the same master as that of the
+ * source mount.
+ *
+ * ---------------------------------------------------------------------------
+ * | MOVE MOUNT OPERATION |
+ * |**************************************************************************
+ * | source-->| shared | private | slave | unbindable |
+ * | dest | | | | |
+ * | | | | | | |
+ * | v | | | | |
+ * |**************************************************************************
+ * | shared | shared (+) | shared (+) | shared(+++) | invalid |
+ * | | | | | |
+ * |non-shared| shared (+*) | private | slave (*) | unbindable |
+ * ***************************************************************************
+ *
+ * (+) the mount is moved to the destination. And is then propagated to
+ * all the mounts in the propagation tree of the destination mount.
+ * (+*) the mount is moved to the destination.
+ * (+++) the mount is moved to the destination and is then propagated to
+ * all the mounts belonging to the destination mount's propagation tree.
+ * the mount is marked as 'shared and slave'.
+ * (*) the mount continues to be a slave at the new location.
+ *
+ * if the source mount is a tree, the operations explained above is
+ * applied to each mount in the tree.
+ * Must be called without spinlocks held, since this function can sleep
+ * in allocations.
+ */
+static int attach_recursive_mnt(struct vfsmount *source_mnt,
+ struct nameidata *nd, struct nameidata *parent_nd)
+{
+ LIST_HEAD(tree_list);
+ struct vfsmount *dest_mnt = nd->mnt;
+ struct dentry *dest_dentry = nd->dentry;
+ struct vfsmount *child, *p;
+
+ if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
+ return -EINVAL;
+
+ if (IS_MNT_SHARED(dest_mnt)) {
+ for (p = source_mnt; p; p = next_mnt(p, source_mnt))
+ set_mnt_shared(p);
+ }
+
+ spin_lock(&vfsmount_lock);
+ if (parent_nd) {
+ detach_mnt(source_mnt, parent_nd);
+ attach_mnt(source_mnt, nd);
+ touch_namespace(current->namespace);
+ } else {
+ mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
+ commit_tree(source_mnt);
+ }
+
+ list_for_each_entry_safe(child, p, &tree_list, mnt_hash) {
+ list_del_init(&child->mnt_hash);
+ commit_tree(child);
+ }
+ spin_unlock(&vfsmount_lock);
+ return 0;
+}
+
static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
{
int err;
return -ENOTDIR;
err = -ENOENT;
- down(&nd->dentry->d_inode->i_sem);
+ mutex_lock(&nd->dentry->d_inode->i_mutex);
if (IS_DEADDIR(nd->dentry->d_inode))
goto out_unlock;
goto out_unlock;
err = -ENOENT;
- spin_lock(&vfsmount_lock);
- if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) {
- struct list_head head;
-
- attach_mnt(mnt, nd);
- list_add_tail(&head, &mnt->mnt_list);
- list_splice(&head, current->namespace->list.prev);
- mntget(mnt);
- err = 0;
- }
- spin_unlock(&vfsmount_lock);
+ if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry))
+ err = attach_recursive_mnt(mnt, nd, NULL);
out_unlock:
- up(&nd->dentry->d_inode->i_sem);
+ mutex_unlock(&nd->dentry->d_inode->i_mutex);
if (!err)
security_sb_post_addmount(mnt, nd);
return err;
}
+/*
+ * recursively change the type of the mountpoint.
+ */
+static int do_change_type(struct nameidata *nd, int flag)
+{
+ struct vfsmount *m, *mnt = nd->mnt;
+ int recurse = flag & MS_REC;
+ int type = flag & ~MS_REC;
+
+ if (nd->dentry != nd->mnt->mnt_root)
+ return -EINVAL;
+
+ down_write(&namespace_sem);
+ spin_lock(&vfsmount_lock);
+ for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
+ change_mnt_propagation(m, type);
+ spin_unlock(&vfsmount_lock);
+ up_write(&namespace_sem);
+ return 0;
+}
+
/*
* do loopback mount.
*/
-static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
+static int do_loopback(struct nameidata *nd, char *old_name, xid_t xid,
+ unsigned long flags, int mnt_flags)
{
struct nameidata old_nd;
struct vfsmount *mnt = NULL;
int err = mount_is_safe(nd);
+ int recurse = flags & MS_REC;
if (err)
return err;
if (!old_name || !*old_name)
if (err)
return err;
- down_write(¤t->namespace->sem);
+ down_write(&namespace_sem);
err = -EINVAL;
- if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) {
- err = -ENOMEM;
- if (recurse)
- mnt = copy_tree(old_nd.mnt, old_nd.dentry);
- else
- mnt = clone_mnt(old_nd.mnt, old_nd.dentry);
+ if (IS_MNT_UNBINDABLE(old_nd.mnt))
+ goto out;
+
+ if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+ goto out;
+
+ err = -ENOMEM;
+ if (recurse)
+ mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0);
+ else
+ mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0);
+
+ if (!mnt)
+ goto out;
+
+ mnt->mnt_flags = mnt_flags;
+ if (flags & MS_XID) {
+ mnt->mnt_xid = xid;
+ mnt->mnt_flags |= MNT_XID;
}
- if (mnt) {
- err = graft_tree(mnt, nd);
- if (err) {
- spin_lock(&vfsmount_lock);
- umount_tree(mnt);
- spin_unlock(&vfsmount_lock);
- } else
- mntput(mnt);
+ err = graft_tree(mnt, nd);
+ if (err) {
+ LIST_HEAD(umount_list);
+ spin_lock(&vfsmount_lock);
+ umount_tree(mnt, 0, &umount_list);
+ spin_unlock(&vfsmount_lock);
+ release_mounts(&umount_list);
}
+ mnt->mnt_flags = mnt_flags;
- up_write(¤t->namespace->sem);
+out:
+ up_write(&namespace_sem);
path_release(&old_nd);
return err;
}
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
*/
-
-static int do_remount(struct nameidata *nd,int flags,int mnt_flags,void *data)
+static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
+ void *data, xid_t xid)
{
int err;
- struct super_block * sb = nd->mnt->mnt_sb;
+ struct super_block *sb = nd->mnt->mnt_sb;
- if (!capable(CAP_SYS_ADMIN))
+ if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_REMOUNT))
return -EPERM;
if (!check_mnt(nd->mnt))
down_write(&sb->s_umount);
err = do_remount_sb(sb, flags, data, 0);
if (!err)
- nd->mnt->mnt_flags=mnt_flags;
+ nd->mnt->mnt_flags = mnt_flags;
up_write(&sb->s_umount);
if (!err)
security_sb_post_remount(nd->mnt, flags, data);
return err;
}
+static inline int tree_contains_unbindable(struct vfsmount *mnt)
+{
+ struct vfsmount *p;
+ for (p = mnt; p; p = next_mnt(p, mnt)) {
+ if (IS_MNT_UNBINDABLE(p))
+ return 1;
+ }
+ return 0;
+}
+
static int do_move_mount(struct nameidata *nd, char *old_name)
{
struct nameidata old_nd, parent_nd;
struct vfsmount *p;
int err = 0;
- if (!capable(CAP_SYS_ADMIN))
+ if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT))
return -EPERM;
if (!old_name || !*old_name)
return -EINVAL;
if (err)
return err;
- down_write(¤t->namespace->sem);
- while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+ down_write(&namespace_sem);
+ while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
err = -EINVAL;
if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
goto out;
err = -ENOENT;
- down(&nd->dentry->d_inode->i_sem);
+ mutex_lock(&nd->dentry->d_inode->i_mutex);
if (IS_DEADDIR(nd->dentry->d_inode))
goto out1;
- spin_lock(&vfsmount_lock);
if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry))
- goto out2;
+ goto out1;
err = -EINVAL;
if (old_nd.dentry != old_nd.mnt->mnt_root)
- goto out2;
+ goto out1;
if (old_nd.mnt == old_nd.mnt->mnt_parent)
- goto out2;
+ goto out1;
if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
S_ISDIR(old_nd.dentry->d_inode->i_mode))
- goto out2;
-
+ goto out1;
+ /*
+ * Don't move a mount residing in a shared parent.
+ */
+ if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent))
+ goto out1;
+ /*
+ * Don't move a mount tree containing unbindable mounts to a destination
+ * mount which is shared.
+ */
+ if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt))
+ goto out1;
err = -ELOOP;
- for (p = nd->mnt; p->mnt_parent!=p; p = p->mnt_parent)
+ for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent)
if (p == old_nd.mnt)
- goto out2;
- err = 0;
+ goto out1;
- detach_mnt(old_nd.mnt, &parent_nd);
- attach_mnt(old_nd.mnt, nd);
-out2:
+ if ((err = attach_recursive_mnt(old_nd.mnt, nd, &parent_nd)))
+ goto out1;
+
+ spin_lock(&vfsmount_lock);
+ /* if the mount is moved, it should no longer be expire
+ * automatically */
+ list_del_init(&old_nd.mnt->mnt_expire);
spin_unlock(&vfsmount_lock);
out1:
- up(&nd->dentry->d_inode->i_sem);
+ mutex_unlock(&nd->dentry->d_inode->i_mutex);
out:
- up_write(¤t->namespace->sem);
+ up_write(&namespace_sem);
if (!err)
path_release(&parent_nd);
path_release(&old_nd);
return err;
}
-static int do_add_mount(struct nameidata *nd, char *type, int flags,
+/*
+ * create a new mount for userspace and request it to be added into the
+ * namespace's tree
+ */
+static int do_new_mount(struct nameidata *nd, char *type, int flags,
int mnt_flags, char *name, void *data)
{
struct vfsmount *mnt;
- int err;
if (!type || !memchr(type, 0, PAGE_SIZE))
return -EINVAL;
/* we need capabilities... */
- if (!capable(CAP_SYS_ADMIN))
+ if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT))
return -EPERM;
mnt = do_kern_mount(type, flags, name, data);
- err = PTR_ERR(mnt);
if (IS_ERR(mnt))
- goto out;
+ return PTR_ERR(mnt);
+
+ return do_add_mount(mnt, nd, mnt_flags, NULL);
+}
- down_write(¤t->namespace->sem);
+/*
+ * add a mount into a namespace's mount tree
+ * - provide the option of adding the new mount to an expiration list
+ */
+int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
+ int mnt_flags, struct list_head *fslist)
+{
+ int err;
+
+ down_write(&namespace_sem);
/* Something was mounted here while we slept */
- while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+ while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
err = -EINVAL;
if (!check_mnt(nd->mnt))
/* Refuse the same filesystem on the same mount point */
err = -EBUSY;
- if (nd->mnt->mnt_sb == mnt->mnt_sb && nd->mnt->mnt_root == nd->dentry)
+ if (nd->mnt->mnt_sb == newmnt->mnt_sb &&
+ nd->mnt->mnt_root == nd->dentry)
goto unlock;
err = -EINVAL;
- if (S_ISLNK(mnt->mnt_root->d_inode->i_mode))
+ if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))
goto unlock;
- mnt->mnt_flags = mnt_flags;
- err = graft_tree(mnt, nd);
+ newmnt->mnt_flags = mnt_flags;
+ if ((err = graft_tree(newmnt, nd)))
+ goto unlock;
+
+ if (fslist) {
+ /* add to the specified expiration list */
+ spin_lock(&vfsmount_lock);
+ list_add_tail(&newmnt->mnt_expire, fslist);
+ spin_unlock(&vfsmount_lock);
+ }
+ up_write(&namespace_sem);
+ return 0;
+
unlock:
- up_write(¤t->namespace->sem);
- mntput(mnt);
-out:
+ up_write(&namespace_sem);
+ mntput(newmnt);
return err;
}
-int copy_mount_options (const void __user *data, unsigned long *where)
+EXPORT_SYMBOL_GPL(do_add_mount);
+
+static void expire_mount(struct vfsmount *mnt, struct list_head *mounts,
+ struct list_head *umounts)
+{
+ spin_lock(&vfsmount_lock);
+
+ /*
+ * Check if mount is still attached, if not, let whoever holds it deal
+ * with the sucker
+ */
+ if (mnt->mnt_parent == mnt) {
+ spin_unlock(&vfsmount_lock);
+ return;
+ }
+
+ /*
+ * Check that it is still dead: the count should now be 2 - as
+ * contributed by the vfsmount parent and the mntget above
+ */
+ if (!propagate_mount_busy(mnt, 2)) {
+ /* delete from the namespace */
+ touch_namespace(mnt->mnt_namespace);
+ list_del_init(&mnt->mnt_list);
+ mnt->mnt_namespace = NULL;
+ umount_tree(mnt, 1, umounts);
+ spin_unlock(&vfsmount_lock);
+ } else {
+ /*
+ * Someone brought it back to life whilst we didn't have any
+ * locks held so return it to the expiration list
+ */
+ list_add_tail(&mnt->mnt_expire, mounts);
+ spin_unlock(&vfsmount_lock);
+ }
+}
+
+/*
+ * process a list of expirable mountpoints with the intent of discarding any
+ * mountpoints that aren't in use and haven't been touched since last we came
+ * here
+ */
+void mark_mounts_for_expiry(struct list_head *mounts)
+{
+ struct namespace *namespace;
+ struct vfsmount *mnt, *next;
+ LIST_HEAD(graveyard);
+
+ if (list_empty(mounts))
+ return;
+
+ spin_lock(&vfsmount_lock);
+
+ /* extract from the expiration list every vfsmount that matches the
+ * following criteria:
+ * - only referenced by its parent vfsmount
+ * - still marked for expiry (marked on the last call here; marks are
+ * cleared by mntput())
+ */
+ list_for_each_entry_safe(mnt, next, mounts, mnt_expire) {
+ if (!xchg(&mnt->mnt_expiry_mark, 1) ||
+ atomic_read(&mnt->mnt_count) != 1)
+ continue;
+
+ mntget(mnt);
+ list_move(&mnt->mnt_expire, &graveyard);
+ }
+
+ /*
+ * go through the vfsmounts we've just consigned to the graveyard to
+ * - check that they're still dead
+ * - delete the vfsmount from the appropriate namespace under lock
+ * - dispose of the corpse
+ */
+ while (!list_empty(&graveyard)) {
+ LIST_HEAD(umounts);
+ mnt = list_entry(graveyard.next, struct vfsmount, mnt_expire);
+ list_del_init(&mnt->mnt_expire);
+
+ /* don't do anything if the namespace is dead - all the
+ * vfsmounts from it are going away anyway */
+ namespace = mnt->mnt_namespace;
+ if (!namespace || !namespace->root)
+ continue;
+ get_namespace(namespace);
+
+ spin_unlock(&vfsmount_lock);
+ down_write(&namespace_sem);
+ expire_mount(mnt, mounts, &umounts);
+ up_write(&namespace_sem);
+ release_mounts(&umounts);
+ mntput(mnt);
+ put_namespace(namespace);
+ spin_lock(&vfsmount_lock);
+ }
+
+ spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL_GPL(mark_mounts_for_expiry);
+
+/*
+ * Some copy_from_user() implementations do not return the exact number of
+ * bytes remaining to copy on a fault. But copy_mount_options() requires that.
+ * Note that this function differs from copy_from_user() in that it will oops
+ * on bad values of `to', rather than returning a short copy.
+ */
+static long exact_copy_from_user(void *to, const void __user * from,
+ unsigned long n)
+{
+ char *t = to;
+ const char __user *f = from;
+ char c;
+
+ if (!access_ok(VERIFY_READ, from, n))
+ return n;
+
+ while (n) {
+ if (__get_user(c, f)) {
+ memset(t, 0, n);
+ break;
+ }
+ *t++ = c;
+ f++;
+ n--;
+ }
+ return n;
+}
+
+int copy_mount_options(const void __user * data, unsigned long *where)
{
int i;
unsigned long page;
unsigned long size;
-
+
*where = 0;
if (!data)
return 0;
if (size > PAGE_SIZE)
size = PAGE_SIZE;
- i = size - copy_from_user((void *)page, data, size);
+ i = size - exact_copy_from_user((void *)page, data, size);
if (!i) {
- free_page(page);
+ free_page(page);
return -EFAULT;
}
if (i != PAGE_SIZE)
* Therefore, if this magic number is present, it carries no information
* and must be discarded.
*/
-long do_mount(char * dev_name, char * dir_name, char *type_page,
+long do_mount(char *dev_name, char *dir_name, char *type_page,
unsigned long flags, void *data_page)
{
struct nameidata nd;
int retval = 0;
int mnt_flags = 0;
+ xid_t xid = 0;
/* Discard magic */
if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
if (data_page)
((char *)data_page)[PAGE_SIZE - 1] = 0;
+ retval = vx_parse_xid(data_page, &xid, 1);
+ if (retval) {
+ mnt_flags |= MNT_XID;
+ /* bind and re-mounts get xid flag */
+ if (flags & (MS_BIND|MS_REMOUNT))
+ flags |= MS_XID;
+ }
+
/* Separate the per-mountpoint flags */
+ if (flags & MS_RDONLY)
+ mnt_flags |= MNT_RDONLY;
if (flags & MS_NOSUID)
mnt_flags |= MNT_NOSUID;
if (flags & MS_NODEV)
mnt_flags |= MNT_NODEV;
if (flags & MS_NOEXEC)
mnt_flags |= MNT_NOEXEC;
- flags &= ~(MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_ACTIVE);
+ if (flags & MS_NOATIME)
+ mnt_flags |= MNT_NOATIME;
+ if (flags & MS_NODIRATIME)
+ mnt_flags |= MNT_NODIRATIME;
- if (vx_ccaps(VXC_SECURE_MOUNT))
+ if (!capable(CAP_SYS_ADMIN))
mnt_flags |= MNT_NODEV;
+ flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
+ MS_NOATIME | MS_NODIRATIME);
/* ... and get the mountpoint */
retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
if (flags & MS_REMOUNT)
retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags,
- data_page);
+ data_page, xid);
else if (flags & MS_BIND)
- retval = do_loopback(&nd, dev_name, flags & MS_REC);
+ retval = do_loopback(&nd, dev_name, xid, flags, mnt_flags);
+ else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+ retval = do_change_type(&nd, flags);
else if (flags & MS_MOVE)
retval = do_move_mount(&nd, dev_name);
else
- retval = do_add_mount(&nd, type_page, flags, mnt_flags,
+ retval = do_new_mount(&nd, type_page, flags, mnt_flags,
dev_name, data_page);
dput_out:
path_release(&nd);
return retval;
}
-int copy_namespace(int flags, struct task_struct *tsk)
+/*
+ * Allocate a new namespace structure and populate it with contents
+ * copied from the namespace of the passed in task structure.
+ */
+struct namespace *dup_namespace(struct task_struct *tsk, struct fs_struct *fs)
{
struct namespace *namespace = tsk->namespace;
struct namespace *new_ns;
struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
- struct fs_struct *fs = tsk->fs;
-
- if (!namespace)
- return 0;
-
- get_namespace(namespace);
-
- if (!(flags & CLONE_NEWNS))
- return 0;
-
- if (!capable(CAP_SYS_ADMIN)) {
- put_namespace(namespace);
- return -EPERM;
- }
+ struct vfsmount *p, *q;
new_ns = kmalloc(sizeof(struct namespace), GFP_KERNEL);
if (!new_ns)
- goto out;
+ return NULL;
atomic_set(&new_ns->count, 1);
- init_rwsem(&new_ns->sem);
INIT_LIST_HEAD(&new_ns->list);
+ init_waitqueue_head(&new_ns->poll);
+ new_ns->event = 0;
- down_write(&tsk->namespace->sem);
+ down_write(&namespace_sem);
/* First pass: copy the tree topology */
- new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root);
+ new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root,
+ CL_COPY_ALL | CL_EXPIRE);
if (!new_ns->root) {
- up_write(&tsk->namespace->sem);
+ up_write(&namespace_sem);
kfree(new_ns);
- goto out;
+ return NULL;
}
spin_lock(&vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
spin_unlock(&vfsmount_lock);
- /* Second pass: switch the tsk->fs->* elements */
- if (fs) {
- struct vfsmount *p, *q;
- write_lock(&fs->lock);
-
- p = namespace->root;
- q = new_ns->root;
- while (p) {
+ /*
+ * Second pass: switch the tsk->fs->* elements and mark new vfsmounts
+ * as belonging to new namespace. We have already acquired a private
+ * fs_struct, so tsk->fs->lock is not needed.
+ */
+ p = namespace->root;
+ q = new_ns->root;
+ while (p) {
+ q->mnt_namespace = new_ns;
+ if (fs) {
if (p == fs->rootmnt) {
rootmnt = p;
fs->rootmnt = mntget(q);
altrootmnt = p;
fs->altrootmnt = mntget(q);
}
- p = next_mnt(p, namespace->root);
- q = next_mnt(q, new_ns->root);
}
- write_unlock(&fs->lock);
+ p = next_mnt(p, namespace->root);
+ q = next_mnt(q, new_ns->root);
}
- up_write(&tsk->namespace->sem);
-
- tsk->namespace = new_ns;
+ up_write(&namespace_sem);
if (rootmnt)
mntput(rootmnt);
if (altrootmnt)
mntput(altrootmnt);
- put_namespace(namespace);
- return 0;
+ return new_ns;
+}
+
+int copy_namespace(int flags, struct task_struct *tsk)
+{
+ struct namespace *namespace = tsk->namespace;
+ struct namespace *new_ns;
+ int err = 0;
+
+ if (!namespace)
+ return 0;
+
+ get_namespace(namespace);
+
+ if (!(flags & CLONE_NEWNS))
+ return 0;
+
+ if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT)) {
+ err = -EPERM;
+ goto out;
+ }
+
+ new_ns = dup_namespace(tsk, tsk->fs);
+ if (!new_ns) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ tsk->namespace = new_ns;
out:
put_namespace(namespace);
- return -ENOMEM;
+ return err;
}
asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
unsigned long dev_page;
char *dir_page;
- retval = copy_mount_options (type, &type_page);
+ retval = copy_mount_options(type, &type_page);
if (retval < 0)
return retval;
if (IS_ERR(dir_page))
goto out1;
- retval = copy_mount_options (dev_name, &dev_page);
+ retval = copy_mount_options(dev_name, &dev_page);
if (retval < 0)
goto out2;
- retval = copy_mount_options (data, &data_page);
+ retval = copy_mount_options(data, &data_page);
if (retval < 0)
goto out3;
lock_kernel();
- retval = do_mount((char*)dev_page, dir_page, (char*)type_page,
- flags, (void*)data_page);
+ retval = do_mount((char *)dev_page, dir_page, (char *)type_page,
+ flags, (void *)data_page);
unlock_kernel();
free_page(data_page);
}
}
-EXPORT_SYMBOL(set_fs_root);
+EXPORT_SYMBOL_GPL(set_fs_root);
/*
* Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
}
}
-EXPORT_SYMBOL(set_fs_pwd);
-
static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
{
struct task_struct *g, *p;
if (fs) {
atomic_inc(&fs->count);
task_unlock(p);
- if (fs->root==old_nd->dentry&&fs->rootmnt==old_nd->mnt)
+ if (fs->root == old_nd->dentry
+ && fs->rootmnt == old_nd->mnt)
set_fs_root(fs, new_nd->mnt, new_nd->dentry);
- if (fs->pwd==old_nd->dentry&&fs->pwdmnt==old_nd->mnt)
+ if (fs->pwd == old_nd->dentry
+ && fs->pwdmnt == old_nd->mnt)
set_fs_pwd(fs, new_nd->mnt, new_nd->dentry);
put_fs_struct(fs);
} else
}
/*
- * Moves the current root to put_root, and sets root/cwd of all processes
- * which had them on the old root to new_root.
+ * pivot_root Semantics:
+ * Moves the root file system of the current process to the directory put_old,
+ * makes new_root as the new root file system of the current process, and sets
+ * root/cwd of all processes which had them on the current root to new_root.
+ *
+ * Restrictions:
+ * The new_root and put_old must be directories, and must not be on the
+ * same file system as the current process root. The put_old must be
+ * underneath new_root, i.e. adding a non-zero number of /.. to the string
+ * pointed to by put_old must yield the same directory as new_root. No other
+ * file system may be mounted on put_old. After all, new_root is a mountpoint.
+ *
+ * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
+ * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives
+ * in this situation.
*
- * Note:
+ * Notes:
* - we don't move root/cwd if they are not at the root (reason: if something
* cared enough to change them, it's probably wrong to force them elsewhere)
* - it's okay to pick a root that isn't the root of a file system, e.g.
* though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
* first.
*/
-
-asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *put_old)
+asmlinkage long sys_pivot_root(const char __user * new_root,
+ const char __user * put_old)
{
struct vfsmount *tmp;
struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd;
lock_kernel();
- error = __user_walk(new_root, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &new_nd);
+ error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
+ &new_nd);
if (error)
goto out0;
error = -EINVAL;
if (!check_mnt(new_nd.mnt))
goto out1;
- error = __user_walk(put_old, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &old_nd);
+ error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd);
if (error)
goto out1;
user_nd.mnt = mntget(current->fs->rootmnt);
user_nd.dentry = dget(current->fs->root);
read_unlock(¤t->fs->lock);
- down_write(¤t->namespace->sem);
- down(&old_nd.dentry->d_inode->i_sem);
+ down_write(&namespace_sem);
+ mutex_lock(&old_nd.dentry->d_inode->i_mutex);
error = -EINVAL;
+ if (IS_MNT_SHARED(old_nd.mnt) ||
+ IS_MNT_SHARED(new_nd.mnt->mnt_parent) ||
+ IS_MNT_SHARED(user_nd.mnt->mnt_parent))
+ goto out2;
if (!check_mnt(user_nd.mnt))
goto out2;
error = -ENOENT;
goto out2;
error = -EBUSY;
if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt)
- goto out2; /* loop */
+ goto out2; /* loop, on the same file system */
error = -EINVAL;
if (user_nd.mnt->mnt_root != user_nd.dentry)
- goto out2;
+ goto out2; /* not a mountpoint */
+ if (user_nd.mnt->mnt_parent == user_nd.mnt)
+ goto out2; /* not attached */
if (new_nd.mnt->mnt_root != new_nd.dentry)
goto out2; /* not a mountpoint */
+ if (new_nd.mnt->mnt_parent == new_nd.mnt)
+ goto out2; /* not attached */
tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
spin_lock(&vfsmount_lock);
if (tmp != new_nd.mnt) {
for (;;) {
if (tmp->mnt_parent == tmp)
- goto out3;
+ goto out3; /* already mounted on put_old */
if (tmp->mnt_parent == new_nd.mnt)
break;
tmp = tmp->mnt_parent;
goto out3;
detach_mnt(new_nd.mnt, &parent_nd);
detach_mnt(user_nd.mnt, &root_parent);
- attach_mnt(user_nd.mnt, &old_nd);
- attach_mnt(new_nd.mnt, &root_parent);
+ attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */
+ attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
+ touch_namespace(current->namespace);
spin_unlock(&vfsmount_lock);
chroot_fs_refs(&user_nd, &new_nd);
security_sb_post_pivotroot(&user_nd, &new_nd);
path_release(&root_parent);
path_release(&parent_nd);
out2:
- up(&old_nd.dentry->d_inode->i_sem);
- up_write(¤t->namespace->sem);
+ mutex_unlock(&old_nd.dentry->d_inode->i_mutex);
+ up_write(&namespace_sem);
path_release(&user_nd);
path_release(&old_nd);
out1:
panic("Can't allocate initial namespace");
atomic_set(&namespace->count, 1);
INIT_LIST_HEAD(&namespace->list);
- init_rwsem(&namespace->sem);
+ init_waitqueue_head(&namespace->poll);
+ namespace->event = 0;
list_add(&mnt->mnt_list, &namespace->list);
namespace->root = mnt;
+ mnt->mnt_namespace = namespace;
init_task.namespace = namespace;
read_lock(&tasklist_lock);
void __init mnt_init(unsigned long mempages)
{
struct list_head *d;
- unsigned long order;
unsigned int nr_hash;
int i;
+ init_rwsem(&namespace_sem);
+
mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount),
- 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
- if (!mnt_cache)
- panic("Cannot create vfsmount cache");
+ 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL);
- order = 0;
- mount_hashtable = (struct list_head *)
- __get_free_pages(GFP_ATOMIC, order);
+ mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC);
if (!mount_hashtable)
panic("Failed to allocate mount hash table\n");
* We don't guarantee that "sizeof(struct list_head)" is necessarily
* a power-of-two.
*/
- nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct list_head);
+ nr_hash = PAGE_SIZE / sizeof(struct list_head);
hash_bits = 0;
do {
hash_bits++;
* from the number of bits we can fit.
*/
nr_hash = 1UL << hash_bits;
- hash_mask = nr_hash-1;
+ hash_mask = nr_hash - 1;
- printk("Mount-cache hash table entries: %d (order: %ld, %ld bytes)\n",
- nr_hash, order, (PAGE_SIZE << order));
+ printk("Mount-cache hash table entries: %d\n", nr_hash);
/* And initialize the newly allocated array */
d = mount_hashtable;
i--;
} while (i);
sysfs_init();
+ subsystem_register(&fs_subsys);
init_rootfs();
init_mount_tree();
}
void __put_namespace(struct namespace *namespace)
{
- down_write(&namespace->sem);
+ struct vfsmount *root = namespace->root;
+ LIST_HEAD(umount_list);
+ namespace->root = NULL;
+ spin_unlock(&vfsmount_lock);
+ down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
- umount_tree(namespace->root);
+ umount_tree(root, 0, &umount_list);
spin_unlock(&vfsmount_lock);
- up_write(&namespace->sem);
+ up_write(&namespace_sem);
+ release_mounts(&umount_list);
kfree(namespace);
}
git://git.onelab.eu / linux-2.6.git / blobdiff