NFS: Fix nfs_migrate_page()

The call to migrate_page() will cause the page->private field to be
cleared.
Also fix up the locking around the page->private transfer, so that we ensure
that calls to nfs_page_find_request() don't end up racing.

Finally, fix up a double free bug: nfs_unlock_request() already calls
nfs_release_request() for us...

Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Tested-by: Andi Kleen <andi@firstfloor.org>
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2009-12-10 09:05:55 -05:00
parent 053e324f67
commit 190f38e5ce

View File

@ -1611,15 +1611,16 @@ int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
if (ret)
goto out_unlock;
page_cache_get(newpage);
spin_lock(&mapping->host->i_lock);
req->wb_page = newpage;
SetPagePrivate(newpage);
set_page_private(newpage, page_private(page));
set_page_private(newpage, (unsigned long)req);
ClearPagePrivate(page);
set_page_private(page, 0);
spin_unlock(&mapping->host->i_lock);
page_cache_release(page);
out_unlock:
nfs_clear_page_tag_locked(req);
nfs_release_request(req);
out:
return ret;
}