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Commit eeb47d12 authored by Mark Fasheh's avatar Mark Fasheh
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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: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent 59be7dc9

fs/ocfs2/aops.c

+10 −10
Original line number Diff line number Diff line
@@ -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);