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authorGoldwyn Rodrigues <rgoldwyn@gmail.com>2011-02-17 09:44:40 -0600
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 13:02:30 -0700
commitb8b602b32fb7533406880478b3872d1e1c6911dc (patch)
tree3bc713b484de21cce113a760986ebb498cb94ecb /fs
parentb2d10ef61c4f466e6f117045358cb48675d49734 (diff)
downloadlinux-linaro-android-b8b602b32fb7533406880478b3872d1e1c6911dc.tar.gz
Treat writes as new when holes span across page boundaries
commit 272b62c1f0f6f742046e45b50b6fec98860208a0 upstream. When a hole spans across page boundaries, the next write forces a read of the block. This could end up reading existing garbage data from the disk in ocfs2_map_page_blocks. This leads to non-zero holes. In order to avoid this, mark the writes as new when the holes span across page boundaries. Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.de> Signed-off-by: jlbec <jlbec@evilplan.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
-rw-r--r--fs/ocfs2/aops.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 1fbb0e20131..bbba782cce2 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1026,6 +1026,12 @@ static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
&cluster_start, &cluster_end);
+ /* treat the write as new if the a hole/lseek spanned across
+ * the page boundary.
+ */
+ new = new | ((i_size_read(inode) <= page_offset(page)) &&
+ (page_offset(page) <= user_pos));
+
if (page == wc->w_target_page) {
map_from = user_pos & (PAGE_CACHE_SIZE - 1);
map_to = map_from + user_len;