Locking question around "...PagePrivate()"

[Menyhart Zoltan <Zoltan.Menyhart@bull.net>]

Hi,

nfs_inode_add_request() runs under the protection of the Page Lock
while setting up SetPagePrivate(), set_page_private().

The consumers of PagePrivate() run also under the protection of the Page Lock.

On the other hand, nfs_inode_remove_request() invoked by
nfs_writeback_release_full() and nfs_commit_release() apparently does
not take the Page Lock.

nfs_inode_remove_request() includes the sequence of

         set_page_private(req->wb_page, 0);
         ClearPagePrivate(req->wb_page);

When the base kernel calls e.g.

	mapping->a_ops->releasepage(page, gfp_mask)

then nfs_release_page() may see an incoherent "private" state.

Should not all the "private" operations be protected by the Page Lock?

Thanks,

Zoltan Menyhart