On Thu, Jul 16, 2015 at 02:18:16PM +0800, Joseph Qi wrote: > I got the problem. > I am not sure why old code uses "result <= 0" even if > it won't return negative value. Could we use "result == 0" instead of > "result <= 0"? I thought about this too, but I'm not sure if it has other side effects. Someone else familiar with this code could comment on this? Thanks, Eryu > > On 2015/7/15 22:30, Eryu Guan wrote: > > Hi all, > > > > I found an infinite loop when unmounting a known bad ext3 image (using > > ext4 driver) with 4.2-rc1 kernel. > > > > The fs image can be found here > > https://bugzilla.kernel.org/show_bug.cgi?id=10882#c1 > > > > Reproduce steps: > > mount -o loop ext3.img /mnt/ext3 > > rm -rf /mnt/ext3/{dev,proc,sys} > > umount /mnt/ext3 # never return > > > > And this issue was introduced by > > 6f6a6fd jbd2: fix ocfs2 corrupt when updating journal superblock fails > > > > It's looping in > > fs/jbd2/journal.c:jbd2_journal_destroy() > > ... > > 1693 while (journal->j_checkpoint_transactions != NULL) { > > 1694 spin_unlock(&journal->j_list_lock); > > 1695 mutex_lock(&journal->j_checkpoint_mutex); > > 1696 jbd2_log_do_checkpoint(journal); > > 1697 mutex_unlock(&journal->j_checkpoint_mutex); > > 1698 spin_lock(&journal->j_list_lock); > > 1699 } > > ... > > > > Because jbd2_cleanup_journal_tail() is returning -EIO on aborted journal > > now instead of 1, and jbd2_log_do_checkpoint() won't cleanup > > journal->j_checkpoint_transactions in this while loop. > > > > A quick hack would be > > > > diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c > > index 4227dc4..1b2ea47 100644 > > --- a/fs/jbd2/checkpoint.c > > +++ b/fs/jbd2/checkpoint.c > > @@ -220,11 +220,13 @@ int jbd2_log_do_checkpoint(journal_t *journal) > > * don't need checkpointing, just eliminate them from the > > * journal straight away. > > */ > > - result = jbd2_cleanup_journal_tail(journal); > > - trace_jbd2_checkpoint(journal, result); > > - jbd_debug(1, "cleanup_journal_tail returned %d\n", result); > > - if (result <= 0) > > - return result; > > + if (!is_journal_aborted(journal)) { > > + result = jbd2_cleanup_journal_tail(journal); > > + trace_jbd2_checkpoint(journal, result); > > + jbd_debug(1, "cleanup_journal_tail returned %d\n", result); > > + if (result <= 0) > > + return result; > > + } > > > > /* > > * OK, we need to start writing disk blocks. Take one transaction > > > > to restore the old behavior (continue on aborted journal). Maybe someone > > has a better fix. > > > > Thanks, > > Eryu > > > > . > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
