[PATCH] ocfs2: Fix oops when racing files truncates with writes into an mmap region

This patch fixes an oops that is reproduced when one races writes to a mmap-ed
region with another process truncating the file.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 17 insertions, 12 deletions

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 1db080135c6..506c24fb507 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1073,12 +1073,15 @@ static void ocfs2_write_failure(struct inode *inode,
         for(i = 0; i < wc->w_num_pages; i++) {
                 tmppage = wc->w_pages[i];
 
-                if (ocfs2_should_order_data(inode))
-                        walk_page_buffers(wc->w_handle, page_buffers(tmppage),
-                                          from, to, NULL,
-                                          ocfs2_journal_dirty_data);
-
-                block_commit_write(tmppage, from, to);
+                if (page_has_buffers(tmppage)) {
+                        if (ocfs2_should_order_data(inode))
+                                walk_page_buffers(wc->w_handle,
+                                                  page_buffers(tmppage),
+                                                  from, to, NULL,
+                                                  ocfs2_journal_dirty_data);
+
+                        block_commit_write(tmppage, from, to);
+                }
         }
 }
 
@@ -1901,12 +1904,14 @@ int ocfs2_write_end_nolock(struct address_space *mapping,
                         to = PAGE_CACHE_SIZE;
                 }
 
-                if (ocfs2_should_order_data(inode))
-                        walk_page_buffers(wc->w_handle, page_buffers(tmppage),
-                                          from, to, NULL,
-                                          ocfs2_journal_dirty_data);
-
-                block_commit_write(tmppage, from, to);
+                if (page_has_buffers(tmppage)) {
+                        if (ocfs2_should_order_data(inode))
+                                walk_page_buffers(wc->w_handle,
+                                                  page_buffers(tmppage),
+                                                  from, to, NULL,
+                                                  ocfs2_journal_dirty_data);
+                        block_commit_write(tmppage, from, to);
+                }
         }
 
 out_write_size: