1 files changed, 18 insertions, 1 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 3b116078b4c3..1ad674fd348c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2834,7 +2834,7 @@ int try_to_free_buffers(struct page *page)
         int ret = 0;
 
         BUG_ON(!PageLocked(page));
-        if (PageDirty(page) || PageWriteback(page))
+        if (PageWriteback(page))
                 return 0;
 
         if (mapping == NULL) {          /* can this still happen? */
@@ -2844,6 +2844,23 @@ int try_to_free_buffers(struct page *page)
 
         spin_lock(&mapping->private_lock);
         ret = drop_buffers(page, &buffers_to_free);
+
+        /*
+         * If the filesystem writes its buffers by hand (eg ext3)
+         * then we can have clean buffers against a dirty page.  We
+         * clean the page here; otherwise the VM will never notice
+         * that the filesystem did any IO at all.
+         *
+         * Also, during truncate, discard_buffer will have marked all
+         * the page's buffers clean.  We discover that here and clean
+         * the page also.
+         *
+         * private_lock must be held over this entire operation in order
+         * to synchronise against __set_page_dirty_buffers and prevent the
+         * dirty bit from being lost.
+         */
+        if (ret)
+                cancel_dirty_page(page, PAGE_CACHE_SIZE);
         spin_unlock(&mapping->private_lock);
 out:
         if (buffers_to_free) {