[18/18] btrfs: fix extent buffer pages release
diff mbox

Message ID 4BAB5939.4060603@cn.fujitsu.com
State New, archived
Headers show

Commit Message

Miao Xie March 25, 2010, 12:38 p.m. UTC
None

Patch
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diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index dbbf9ca..a4391a6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3099,6 +3099,31 @@  static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
 	return eb;
 }
 
+/*
+ * Used for releasing extent buffer page.
+ *
+ * can't release the first page of extent buffer at the beginning, because 
+ * extent_buffer_page() gets address_space just by the first page->mapping,
+ * and then gets other pages.
+ */
+static void __release_extent_buffer_page(struct extent_buffer *eb)
+{
+	unsigned long index, num_pages;
+	struct page *page;
+
+	num_pages = num_extent_pages(eb->start, eb->len);
+	for (index = 1; index < num_pages; index++) {
+		page = extent_buffer_page(eb, index);
+		if (page)
+			page_cache_release(page);
+		else
+			break;
+	}
+	page = extent_buffer_page(eb, 0);
+	if (page)
+		page_cache_release(page);
+}
+
 static void __free_extent_buffer(struct extent_buffer *eb)
 {
 #if LEAK_DEBUG
@@ -3187,9 +3212,7 @@  struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 free_eb:
 	if (!atomic_dec_and_test(&eb->refs))
 		return exists;
-	for (index = 1; index < i; index++)
-		page_cache_release(extent_buffer_page(eb, index));
-	page_cache_release(extent_buffer_page(eb, 0));
+	__release_extent_buffer_page(eb);
 	__free_extent_buffer(eb);
 	return exists;
 }
@@ -3863,9 +3886,7 @@  int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
 		goto out;
 	}
 	/* at this point we can safely release the extent buffer */
-	num_pages = num_extent_pages(eb->start, eb->len);
-	for (i = 0; i < num_pages; i++)
-		page_cache_release(extent_buffer_page(eb, i));
+	__release_extent_buffer_page(eb);
 	rb_erase(&eb->rb_node, &tree->buffer);
 	__free_extent_buffer(eb);
 out: