ext4: Mark the buffer_heads as dirty and uptodate after prepare_write

We need to make sure we mark the buffer_heads as dirty and uptodate
so that block_write_full_page write them correctly.

This fixes mmap corruptions that can occur in low memory situations.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5a130b56f1cf..be21a5ae33cb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2329,6 +2329,8 @@ static int ext4_da_writepage(struct page *page,
                         unlock_page(page);
                         return 0;
                 }
+                /* now mark the buffer_heads as dirty and uptodate */
+                block_commit_write(page, 0, PAGE_CACHE_SIZE);
         }
 
         if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))