summaryrefslogtreecommitdiffstats
path: root/fs
diff options
context:
space:
mode:
authorTao Ma <tao.ma@oracle.com>2010-02-01 10:05:33 +0100
committerJoel Becker <joel.becker@oracle.com>2010-02-03 03:15:35 +0100
commit0a1ea437d87af830786605813972e8e277992917 (patch)
treee3b176e8d592e30aa9bd981ba58e1d625fc16f27 /fs
parentocfs2: Fix memory overflow in cow_by_page. (diff)
downloadlinux-0a1ea437d87af830786605813972e8e277992917.tar.xz
linux-0a1ea437d87af830786605813972e8e277992917.zip
ocfs2: Only bug out when page size is larger than cluster size.
In CoW, we have to make sure that the page is already written out to the disk. So we have a BUG_ON(PageDirty(page)). In ppc platform we have pagesize=64K, so if the cs=4K, if the file have fragmented clusters, we will map the page many times. See this file as an example. Tree Depth: 0 Count: 19 Next Free Rec: 14 ## Offset Clusters Block# Flags 0 0 4 2164864 0x2 Refcounted 1 4 2 9302792 0x2 Refcounted ... We have to replace the extent recs one by one, so the page with index 0 will be mapped and dirtied twice. I'd like to leave the BUG_ON there while adding a check so that in case we meet with an error in other platforms, we can find it easily. Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/ocfs2/refcounttree.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 5b64468de0b0..8ae65c9c020c 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -2957,8 +2957,12 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
page = grab_cache_page(mapping, page_index);
- /* This page can't be dirtied before we CoW it out. */
- BUG_ON(PageDirty(page));
+ /*
+ * In case PAGE_CACHE_SIZE <= CLUSTER_SIZE, This page
+ * can't be dirtied before we CoW it out.
+ */
+ if (PAGE_CACHE_SIZE <= OCFS2_SB(sb)->s_clustersize)
+ BUG_ON(PageDirty(page));
if (!PageUptodate(page)) {
ret = block_read_full_page(page, ocfs2_get_block);