Merge branch 'mount.part1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[platform/kernel/linux-rpi.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index badfd28..a677b59 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -693,9 +693,6 @@ static struct mountpoint *lookup_mountpoint(struct dentry *dentry)
 
        hlist_for_each_entry(mp, chain, m_hash) {
                if (mp->m_dentry == dentry) {
-                       /* might be worth a WARN_ON() */
-                       if (d_unlinked(dentry))
-                               return ERR_PTR(-ENOENT);
                        mp->m_count++;
                        return mp;
                }
@@ -709,6 +706,9 @@ static struct mountpoint *get_mountpoint(struct dentry *dentry)
        int ret;
 
        if (d_mountpoint(dentry)) {
+               /* might be worth a WARN_ON() */
+               if (d_unlinked(dentry))
+                       return ERR_PTR(-ENOENT);
 mountpoint:
                read_seqlock_excl(&mount_lock);
                mp = lookup_mountpoint(dentry);
@@ -1358,7 +1358,7 @@ static void namespace_unlock(void)
        if (likely(hlist_empty(&head)))
                return;
 
-       synchronize_rcu();
+       synchronize_rcu_expedited();
 
        group_pin_kill(&head);
 }
@@ -1538,8 +1538,13 @@ static int do_umount(struct mount *mnt, int flags)
 
        namespace_lock();
        lock_mount_hash();
-       event++;
 
+       /* Recheck MNT_LOCKED with the locks held */
+       retval = -EINVAL;
+       if (mnt->mnt.mnt_flags & MNT_LOCKED)
+               goto out;
+
+       event++;
        if (flags & MNT_DETACH) {
                if (!list_empty(&mnt->mnt_list))
                        umount_tree(mnt, UMOUNT_PROPAGATE);
@@ -1553,6 +1558,7 @@ static int do_umount(struct mount *mnt, int flags)
                        retval = 0;
                }
        }
+out:
        unlock_mount_hash();
        namespace_unlock();
        return retval;
@@ -1643,7 +1649,7 @@ int ksys_umount(char __user *name, int flags)
                goto dput_and_out;
        if (!check_mnt(mnt))
                goto dput_and_out;
-       if (mnt->mnt.mnt_flags & MNT_LOCKED)
+       if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */
                goto dput_and_out;
        retval = -EPERM;
        if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))
@@ -1726,8 +1732,14 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
                for (s = r; s; s = next_mnt(s, r)) {
                        if (!(flag & CL_COPY_UNBINDABLE) &&
                            IS_MNT_UNBINDABLE(s)) {
-                               s = skip_mnt_tree(s);
-                               continue;
+                               if (s->mnt.mnt_flags & MNT_LOCKED) {
+                                       /* Both unbindable and locked. */
+                                       q = ERR_PTR(-EPERM);
+                                       goto out;
+                               } else {
+                                       s = skip_mnt_tree(s);
+                                       continue;
+                               }
                        }
                        if (!(flag & CL_COPY_MNT_NS_FILE) &&
                            is_mnt_ns_file(s->mnt.mnt_root)) {
@@ -1780,7 +1792,7 @@ void drop_collected_mounts(struct vfsmount *mnt)
 {
        namespace_lock();
        lock_mount_hash();
-       umount_tree(real_mount(mnt), UMOUNT_SYNC);
+       umount_tree(real_mount(mnt), 0);
        unlock_mount_hash();
        namespace_unlock();
 }
@@ -2683,7 +2695,7 @@ static long exact_copy_from_user(void *to, const void __user * from,
        const char __user *f = from;
        char c;
 
-       if (!access_ok(VERIFY_READ, from, n))
+       if (!access_ok(from, n))
                return n;
 
        current->kernel_uaccess_faults_ok++;