1 files changed, 64 insertions, 5 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index d2a4d1bb2d57..6024877335ca 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.
@@ -971,9 +1005,19 @@ grow_dev_page(struct block_device *bdev, sector_t block,
 	struct buffer_head *bh;
 	sector_t end_block;
 	int ret = 0;		/* Will call free_more_memory() */
+	gfp_t gfp_mask;
+
+	gfp_mask = mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS;
+	gfp_mask |= __GFP_MOVABLE;
+	/*
+	 * XXX: __getblk_slow() can not really deal with failure and
+	 * will endlessly loop on improvised global reclaim.  Prefer
+	 * looping in the allocator rather than here, at least that
+	 * code knows what it's doing.
+	 */
+	gfp_mask |= __GFP_NOFAIL;
 
-	page = find_or_create_page(inode->i_mapping, index,
-		(mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE);
+	page = find_or_create_page(inode->i_mapping, index, gfp_mask);
 	if (!page)
 		return ret;
 
@@ -1454,7 +1498,8 @@ static void discard_buffer(struct buffer_head * bh)
  * block_invalidatepage - invalidate part or all of a buffer-backed page
  *
  * @page: the page which is affected
- * @offset: the index of the truncation point
+ * @offset: start of the range to invalidate
+ * @length: length of the range to invalidate
  *
  * block_invalidatepage() is called when all or part of the page has become
  * invalidated by a truncate operation.
@@ -1465,15 +1510,22 @@ static void discard_buffer(struct buffer_head * bh)
  * point.  Because the caller is about to free (and possibly reuse) those
  * blocks on-disk.
  */
-void block_invalidatepage(struct page *page, unsigned long offset)
+void block_invalidatepage(struct page *page, unsigned int offset,
+			  unsigned int length)
 {
 	struct buffer_head *head, *bh, *next;
 	unsigned int curr_off = 0;
+	unsigned int stop = length + offset;
 
 	BUG_ON(!PageLocked(page));
 	if (!page_has_buffers(page))
 		goto out;
 
+	/*
+	 * Check for overflow
+	 */
+	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
 	head = page_buffers(page);
 	bh = head;
 	do {
@@ -1481,6 +1533,12 @@ void block_invalidatepage(struct page *page, unsigned long offset)
 		next = bh->b_this_page;
 
 		/*
+		 * Are we still fully in range ?
+		 */
+		if (next_off > stop)
+			goto out;
+
+		/*
 		 * is this block fully invalidated?
 		 */
 		if (offset <= curr_off)
@@ -1501,6 +1559,7 @@ out:
 }
 EXPORT_SYMBOL(block_invalidatepage);
 
+
 /*
  * We attach and possibly dirty the buffers atomically wrt
  * __set_page_dirty_buffers() via private_lock.  try_to_free_buffers
@@ -2841,7 +2900,7 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
 		 * they may have been added in ext3_writepage().  Make them
 		 * freeable here, so the page does not leak.
 		 */
-		do_invalidatepage(page, 0);
+		do_invalidatepage(page, 0, PAGE_CACHE_SIZE);
 		unlock_page(page);
 		return 0; /* don't care */
 	}