[PATCH] xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage()

Jan Kara
2013-03-14T13:31:06Z

When a dirty page is truncated from a file but reclaim gets to it before
truncate_inode_pages(), we hit WARN_ON(delalloc) in
xfs_vm_releasepage(). This is because reclaim tries to write the page,
xfs_vm_writepage() just bails out (leaving page clean) and thus reclaim
thinks it can continue and calls xfs_vm_releasepage() on page with dirty
buffers.

Fix the issue by redirtying the page in xfs_vm_writepage(). This makes
reclaim stop reclaiming the page and also logically it keeps page in a
more consistent state where page with dirty buffers has PageDirty set.

Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/xfs/xfs_aops.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 5f707e5..3244c98 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -953,13 +953,13 @@ xfs_vm_writepage(
unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1);

/*
- * Just skip the page if it is fully outside i_size, e.g. due
- * to a truncate operation that is in progress.
+ * Skip the page if it is fully outside i_size, e.g. due to a
+ * truncate operation that is in progress. We must redirty the
+ * page so that reclaim stops reclaiming it. Otherwise
+ * xfs_vm_releasepage() is called on it and gets confused.
*/
- if (page->index >= end_index + 1 || offset_into_page == 0) {
- unlock_page(page);
- return 0;
- }
+ if (page->index >= end_index + 1 || offset_into_page == 0)
+ goto redirty;

/*
* The page straddles i_size. It must be zeroed out on each
--
1.7.1