From: Chris Mason <chris.mason@oracle.com>
Date: Fri, 11 Apr 2008 14:51:07 +0000 (-0400)
Subject: Btrfs: Add extra checks to avoid removing extent_state from pages we can't free
X-Git-Tag: v2.6.29-rc1~27^2~9^2~55^2~56^2~30^2~238
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3dd39914bc0737d055c780d29c20a1d117819cdb;p=karo-tx-linux.git

Btrfs: Add extra checks to avoid removing extent_state from pages we can't free

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index cf1de75f088a..e22960e23501 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -436,6 +436,12 @@ static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 	struct extent_map_tree *map;
 	int ret;
 
+	if (page_count(page) > 3) {
+		/* once for page->private, once for the caller, once
+		 * once for the page cache
+		 */
+		return 0;
+	}
 	tree = &BTRFS_I(page->mapping->host)->io_tree;
 	map = &BTRFS_I(page->mapping->host)->extent_tree;
 	ret = try_release_extent_mapping(map, tree, page, gfp_flags);