1 files changed, 29 insertions, 0 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index de50b16a8f67..43e4abd67be7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -121,6 +121,33 @@ void ext4_evict_inode(struct inode *inode)
 
         trace_ext4_evict_inode(inode);
         if (inode->i_nlink) {
+                /*
+                 * When journalling data dirty buffers are tracked only in the
+                 * journal. So although mm thinks everything is clean and
+                 * ready for reaping the inode might still have some pages to
+                 * write in the running transaction or waiting to be
+                 * checkpointed. Thus calling jbd2_journal_invalidatepage()
+                 * (via truncate_inode_pages()) to discard these buffers can
+                 * cause data loss. Also even if we did not discard these
+                 * buffers, we would have no way to find them after the inode
+                 * is reaped and thus user could see stale data if he tries to
+                 * read them before the transaction is checkpointed. So be
+                 * careful and force everything to disk here... We use
+                 * ei->i_datasync_tid to store the newest transaction
+                 * containing inode's data.
+                 *
+                 * Note that directories do not have this problem because they
+                 * don't use page cache.
+                 */
+                if (ext4_should_journal_data(inode) &&
+                    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
+                        journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+                        tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
+
+                        jbd2_log_start_commit(journal, commit_tid);
+                        jbd2_log_wait_commit(journal, commit_tid);
+                        filemap_write_and_wait(&inode->i_data);
+                }
                 truncate_inode_pages(&inode->i_data, 0);
                 goto no_delete;
         }
@@ -970,6 +997,7 @@ static int ext4_journalled_write_end(struct file *file,
         if (new_i_size > inode->i_size)
                 i_size_write(inode, pos+copied);
         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+        EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
         if (new_i_size > EXT4_I(inode)->i_disksize) {
                 ext4_update_i_disksize(inode, new_i_size);
                 ret2 = ext4_mark_inode_dirty(handle, inode);
@@ -1678,6 +1706,7 @@ static int __ext4_journalled_writepage(struct page *page,
                                 write_end_fn);
         if (ret == 0)
                 ret = err;
+        EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
         err = ext4_journal_stop(handle);
         if (!ret)
                 ret = err;