Index: linux/fs/buffer.c
===================================================================
--- linux.orig/fs/buffer.c
+++ linux/fs/buffer.c
@@ -509,13 +509,18 @@ __find_get_block_slow(struct block_devic
 	struct buffer_head *head;
 	struct page *page;
 	int all_mapped = 1;
+	int spinlock = 0;
 
 	index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits);
 	page = find_get_page(bd_mapping, index);
 	if (!page)
 		goto out;
 
+	if (unlikely(TestSetPageLocked(page))) {
 	spin_lock(&bd_mapping->private_lock);
+		spinlock = 1;
+	}
+
 	if (!page_has_buffers(page))
 		goto out_unlock;
 	head = page_buffers(page);
@@ -536,7 +541,7 @@ __find_get_block_slow(struct block_devic
 	 * file io on the block device and getblk.  It gets dealt with
 	 * elsewhere, don't buffer_error if we had some unmapped buffers
 	 */
-	if (all_mapped) {
+	if (unlikely(all_mapped)) {
 		printk("__find_get_block_slow() failed. "
 			"block=%llu, b_blocknr=%llu\n",
 			(unsigned long long)block, (unsigned long long)bh->b_blocknr);
@@ -544,7 +549,10 @@ __find_get_block_slow(struct block_devic
 		printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits);
 	}
 out_unlock:
+	if (unlikely(spinlock))
 	spin_unlock(&bd_mapping->private_lock);
+	else
+		unlock_page(page);
 	page_cache_release(page);
 out:
 	return ret;