ocfs2: Fix deadlock when allocating page

We cannot call grab_cache_page() when holding filesystem locks or with
a transaction started as grab_cache_page() calls page allocation with
GFP_KERNEL flag and thus page reclaim can recurse back into the filesystem
causing deadlocks or various assertion failures. We have to use
find_or_create_page() instead and pass it GFP_NOFS as we do with other
allocations.

Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tao Ma <tao.ma@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 73a11ccfd4c..0afeda83120 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -2960,7 +2960,7 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
                 if (map_end & (PAGE_CACHE_SIZE - 1))
                         to = map_end & (PAGE_CACHE_SIZE - 1);
 
-                page = grab_cache_page(mapping, page_index);
+                page = find_or_create_page(mapping, page_index, GFP_NOFS);
 
                 /*
                  * In case PAGE_CACHE_SIZE <= CLUSTER_SIZE, This page
@@ -3179,7 +3179,8 @@ static int ocfs2_cow_sync_writeback(struct super_block *sb,
                 if (map_end > end)
                         map_end = end;
 
-                page = grab_cache_page(context->inode->i_mapping, page_index);
+                page = find_or_create_page(context->inode->i_mapping,
+                                           page_index, GFP_NOFS);
                 BUG_ON(!page);
 
                 wait_on_page_writeback(page);