ocfs2: Fix invalid assertion during write on 64k pages

The write path code intends to bug if a math error (or unhandled case)
results in a write outside of the current cluster boundaries. The actual
BUG_ON() statements however are incorrect, leading to a crash on kernels
with 64k page size. Fix those by checking against the right variables.

Also, move the assertions higher up within the functions so that they trip
*before* the code starts to mark buffers.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 0023b31..a480b09 100644 (file)
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -798,6 +798,11 @@ int ocfs2_map_and_write_splice_data(struct inode *inode,
        }
        to = from + bytes;
 
+       BUG_ON(from > PAGE_CACHE_SIZE);
+       BUG_ON(to > PAGE_CACHE_SIZE);
+       BUG_ON(from < cluster_start);
+       BUG_ON(to > cluster_end);
+
        if (wc->w_this_page_new)
                ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
                                            cluster_start, cluster_end, 1);
@@ -809,11 +814,6 @@ int ocfs2_map_and_write_splice_data(struct inode *inode,
                goto out;
        }
 
-       BUG_ON(from > PAGE_CACHE_SIZE);
-       BUG_ON(to > PAGE_CACHE_SIZE);
-       BUG_ON(from > osb->s_clustersize);
-       BUG_ON(to > osb->s_clustersize);
-
        src = buf->ops->map(sp->s_pipe, buf, 1);
        dst = kmap_atomic(wc->w_this_page, KM_USER1);
        memcpy(dst + from, src + src_from, bytes);
@@ -890,6 +890,11 @@ int ocfs2_map_and_write_user_data(struct inode *inode,
 
        to = from + bytes;
 
+       BUG_ON(from > PAGE_CACHE_SIZE);
+       BUG_ON(to > PAGE_CACHE_SIZE);
+       BUG_ON(from < cluster_start);
+       BUG_ON(to > cluster_end);
+
        if (wc->w_this_page_new)
                ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
                                            cluster_start, cluster_end, 1);
@@ -901,11 +906,6 @@ int ocfs2_map_and_write_user_data(struct inode *inode,
                goto out;
        }
 
-       BUG_ON(from > PAGE_CACHE_SIZE);
-       BUG_ON(to > PAGE_CACHE_SIZE);
-       BUG_ON(from > osb->s_clustersize);
-       BUG_ON(to > osb->s_clustersize);
-
        dst = kmap(wc->w_this_page);
        memcpy(dst + from, bp->b_src_buf + src_from, bytes);
        kunmap(wc->w_this_page);