VServer 1.9.2 (patch-2.6.8.1-vs1.9.2.diff)

[linux-2.6.git] / fs / super.c

diff --git a/fs/super.c b/fs/super.c
index 8d9bff1..37b76d7 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -35,6 +35,8 @@
 #include <linux/vfs.h>
 #include <linux/writeback.h>           /* for the emergency remount stuff */
 #include <linux/idr.h>
+#include <linux/devpts_fs.h>
+#include <linux/proc_fs.h>
 #include <asm/uaccess.h>
 
 
@@ -569,14 +571,19 @@ static spinlock_t unnamed_dev_lock = SPIN_LOCK_UNLOCKED;/* protects the above */
 int set_anon_super(struct super_block *s, void *data)
 {
        int dev;
+       int error;
 
-       spin_lock(&unnamed_dev_lock);
-       if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0) {
-               spin_unlock(&unnamed_dev_lock);
+ retry:
+       if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0)
                return -ENOMEM;
-       }
-       dev = idr_get_new(&unnamed_dev_idr, NULL);
+       spin_lock(&unnamed_dev_lock);
+       error = idr_get_new(&unnamed_dev_idr, NULL, &dev);
        spin_unlock(&unnamed_dev_lock);
+       if (error == -EAGAIN)
+               /* We raced and lost with another CPU. */
+               goto retry;
+       else if (error)
+               return -EAGAIN;
 
        if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
                spin_lock(&unnamed_dev_lock);
@@ -781,6 +788,13 @@ do_kern_mount(const char *fstype, int flags, const char *name, void *data)
        sb = type->get_sb(type, flags, name, data);
        if (IS_ERR(sb))
                goto out_free_secdata;
+
+       error = -EPERM;
+       if (!capable(CAP_SYS_ADMIN) && !sb->s_bdev &&
+               (sb->s_magic != PROC_SUPER_MAGIC) &&
+               (sb->s_magic != DEVPTS_SUPER_MAGIC))
+               goto out_sb;
+
        error = security_sb_kern_mount(sb, secdata);
        if (error)
                goto out_sb;
@@ -788,6 +802,7 @@ do_kern_mount(const char *fstype, int flags, const char *name, void *data)
        mnt->mnt_root = dget(sb->s_root);
        mnt->mnt_mountpoint = sb->s_root;
        mnt->mnt_parent = mnt;
+       mnt->mnt_namespace = current->namespace;
        up_write(&sb->s_umount);
        put_filesystem(type);
        return mnt;
@@ -804,6 +819,8 @@ out:
        return (struct vfsmount *)sb;
 }
 
+EXPORT_SYMBOL_GPL(do_kern_mount);
+
 struct vfsmount *kern_mount(struct file_system_type *type)
 {
        return do_kern_mount(type->name, 0, type->name, NULL);