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ocfs2: Only bug out when page size is larger than cluster size.

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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>
This commit is contained in:
Tao Ma 2010-02-01 17:05:33 +08:00 committed by Joel Becker
parent d622b89a2f
commit 0a1ea437d8
1 changed files with 6 additions and 2 deletions
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8
fs/ocfs2/refcounttree.c
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@ -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);