From: Miklos Szeredi <[EMAIL PROTECTED]>

Allow clone_mnt() to return errors other than ENOMEM.  This will be
used for returning a different error value when the number of user
mounts goes over the limit.

Fix copy_tree() to return EPERM for unbindable mounts.

Don't propagate further from dup_mnt_ns() as that copy_tree() can only
fail with -ENOMEM.

Signed-off-by: Miklos Szeredi <[EMAIL PROTECTED]>
---

Index: linux/fs/namespace.c
===================================================================
--- linux.orig/fs/namespace.c   2007-04-12 13:54:36.000000000 +0200
+++ linux/fs/namespace.c        2007-04-12 14:04:25.000000000 +0200
@@ -261,42 +261,42 @@ static struct vfsmount *clone_mnt(struct
 {
        struct super_block *sb = old->mnt_sb;
        struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
+       if (!mnt)
+               return ERR_PTR(-ENOMEM);
 
-       if (mnt) {
-               mnt->mnt_flags = old->mnt_flags;
-               atomic_inc(&sb->s_active);
-               mnt->mnt_sb = sb;
-               mnt->mnt_root = dget(root);
-               mnt->mnt_mountpoint = mnt->mnt_root;
-               mnt->mnt_parent = mnt;
-
-               /* don't copy the MNT_USER flag */
-               mnt->mnt_flags &= ~MNT_USER;
-               if (flag & CL_SETUSER)
-                       set_mnt_user(mnt);
-
-               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);
+       mnt->mnt_flags = old->mnt_flags;
+       atomic_inc(&sb->s_active);
+       mnt->mnt_sb = sb;
+       mnt->mnt_root = dget(root);
+       mnt->mnt_mountpoint = mnt->mnt_root;
+       mnt->mnt_parent = mnt;
+
+       /* don't copy the MNT_USER flag */
+       mnt->mnt_flags &= ~MNT_USER;
+       if (flag & CL_SETUSER)
+               set_mnt_user(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);
-               }
+       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;
 }
@@ -781,11 +781,11 @@ struct vfsmount *copy_tree(struct vfsmou
        struct nameidata nd;
 
        if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
-               return NULL;
+               return ERR_PTR(-EPERM);
 
        res = q = clone_mnt(mnt, dentry, flag);
-       if (!q)
-               goto Enomem;
+       if (IS_ERR(q))
+               goto error;
        q->mnt_mountpoint = mnt->mnt_mountpoint;
 
        p = mnt;
@@ -806,8 +806,8 @@ struct vfsmount *copy_tree(struct vfsmou
                        nd.mnt = q;
                        nd.dentry = p->mnt_mountpoint;
                        q = clone_mnt(p, p->mnt_root, flag);
-                       if (!q)
-                               goto Enomem;
+                       if (IS_ERR(q))
+                               goto error;
                        spin_lock(&vfsmount_lock);
                        list_add_tail(&q->mnt_list, &res->mnt_list);
                        attach_mnt(q, &nd);
@@ -815,7 +815,7 @@ struct vfsmount *copy_tree(struct vfsmou
                }
        }
        return res;
-Enomem:
+ error:
        if (res) {
                LIST_HEAD(umount_list);
                spin_lock(&vfsmount_lock);
@@ -823,7 +823,7 @@ Enomem:
                spin_unlock(&vfsmount_lock);
                release_mounts(&umount_list);
        }
-       return NULL;
+       return q;
 }
 
 /*
@@ -999,13 +999,13 @@ static int do_loopback(struct nameidata 
                goto out;
 
        clone_flags = (flags & MS_SETUSER) ? CL_SETUSER : 0;
-       err = -ENOMEM;
        if (flags & MS_REC)
                mnt = copy_tree(old_nd.mnt, old_nd.dentry, clone_flags);
        else
                mnt = clone_mnt(old_nd.mnt, old_nd.dentry, clone_flags);
 
-       if (!mnt)
+       err = PTR_ERR(mnt);
+       if (IS_ERR(mnt))
                goto out;
 
        err = graft_tree(mnt, nd);
@@ -1558,7 +1558,7 @@ static struct mnt_namespace *dup_mnt_ns(
        /* First pass: copy the tree topology */
        new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root,
                                        CL_COPY_ALL | CL_EXPIRE);
-       if (!new_ns->root) {
+       if (IS_ERR(new_ns->root)) {
                up_write(&namespace_sem);
                kfree(new_ns);
                return NULL;
Index: linux/fs/pnode.c
===================================================================
--- linux.orig/fs/pnode.c       2007-04-12 13:26:42.000000000 +0200
+++ linux/fs/pnode.c    2007-04-12 14:04:25.000000000 +0200
@@ -187,8 +187,9 @@ int propagate_mnt(struct vfsmount *dest_
 
                source =  get_source(m, prev_dest_mnt, prev_src_mnt, &type);
 
-               if (!(child = copy_tree(source, source->mnt_root, type))) {
-                       ret = -ENOMEM;
+               child = copy_tree(source, source->mnt_root, type);
+               if (IS_ERR(child)) {
+                       ret = PTR_ERR(child);
                        list_splice(tree_list, tmp_list.prev);
                        goto out;
                }

--
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