On Fri, 14 Apr 2006 19:51:14 +0200, "Julio M. Merino Vidal"
<jmmv84@gmail.com> wrote:

> Hello,
> 
> PR kern/31944 lists three issues that make tmpfs consume too much
> memory.  The attached patch addresses the first of them.  It does the
> following:
> 
> - Only keep the node identifier/generation number when deleting a node.
>   The size of tmpfs_nid is much smaller than that of tmpfs_node.
> - Avoid keeping nodes that were initialized but then discarded due to some
>   error.  See the keepit parameter to the tmpfs_free_node function.
> 
> I have read the replies to that PR but the proposed solutions seem to be
> "not right".  Also, one question that arises... can there be two live files in a
> file system with the same node number?  If not, all those solutions do not
> seem to address this...
> 
There's a lot of code that assumes that a <device,inode> pair uniquely
identify files.  For example, in src/bin/pax/tables.h, there's this
comment:

/*
 * file hard link structure (hashed by dev/ino and chained) used to find the
 * hard links in a file system or with some archive formats (cpio)
 */


		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb