1 files changed, 34 insertions, 0 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index f93392e2df12..4d7433534f5c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -83,6 +83,40 @@ void unlock_buffer(struct buffer_head *bh)
 EXPORT_SYMBOL(unlock_buffer);
 
 /*
+ * Returns if the page has dirty or writeback buffers. If all the buffers
+ * are unlocked and clean then the PageDirty information is stale. If
+ * any of the pages are locked, it is assumed they are locked for IO.
+ */
+void buffer_check_dirty_writeback(struct page *page,
+                                     bool *dirty, bool *writeback)
+{
+        struct buffer_head *head, *bh;
+        *dirty = false;
+        *writeback = false;
+
+        BUG_ON(!PageLocked(page));
+
+        if (!page_has_buffers(page))
+                return;
+
+        if (PageWriteback(page))
+                *writeback = true;
+
+        head = page_buffers(page);
+        bh = head;
+        do {
+                if (buffer_locked(bh))
+                        *writeback = true;
+
+                if (buffer_dirty(bh))
+                        *dirty = true;
+
+                bh = bh->b_this_page;
+        } while (bh != head);
+}
+EXPORT_SYMBOL(buffer_check_dirty_writeback);
+
+/*
  * Block until a buffer comes unlocked.  This doesn't stop it
  * from becoming locked again - you have to lock it yourself
  * if you want to preserve its state.