ext4: Initialize fsync transaction ids in ext4_new_inode()

When allocating a new inode, we need to make sure i_sync_tid and
i_datasync_tid are initialized.  Otherwise, one or both of these two
values could be left initialized to zero, which could potentially
result in BUG_ON in jbd2_journal_commit_transaction.

(This could happen by having journal->commit_request getting set to
zero, which could wake up the kjournald process even though there is
no running transaction, which then causes a BUG_ON via the 
J_ASSERT(j_ruinning_transaction != NULL) statement.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 2fd3b0e41787..a679a482c986 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1054,6 +1054,11 @@ got:
                 }
         }
 
+        if (ext4_handle_valid(handle)) {
+                ei->i_sync_tid = handle->h_transaction->t_tid;
+                ei->i_datasync_tid = handle->h_transaction->t_tid;
+        }
+
         err = ext4_mark_inode_dirty(handle, inode);
         if (err) {
                 ext4_std_error(sb, err);