On Sun, Jun 23, 2013 at 01:36:28PM -0400, Theodore Ts'o wrote: > On Fri, Jun 21, 2013 at 09:29:31PM +0800, Younger Liu wrote: > > > > This bug was triggered by the following scenario: > > In ocfs2 file system, allocate a very large disk space for a small file > > with ocfs2_fallocate(), while the journal file size is 32M. > > > > Because there are much many journal blocks needed by jbd2_journal_restart(), > > so that nblocks is greater than journal->j_max_transaction_buffers > > in start_this_handle(), and then return -ENOSPC. > > Ah, I see. I have a patch that should prevent the kernel from > crashing in this situation, and which adds some additional checks to > make sure no one tries to use the handle after jbd2_journal_restart() > fails in this circumstance. > > However, you may want to further pursue a fix in ocfs2 so you don't > actually return ENOSPC to userspace, since it is a very misleading > error message --- it's not that the file system is out of space, but > that the journal is too small for the amount of space that you are > trying to allocate using fallocate(). > > I would think a better way of handling this situation would be to log > a warning message that the journal is probably too small, and then to > break up the fallocate into smaller chunks, so that it can > successfully complete despite the fact that the journal was > unfortunately missized. Yes, this solution is a good one. Joel > > I'll be sending the proposed fix in a moment; could you check and see > if the patch prevents ocfs2/jbd2 from tripping over the assertion > given your test case? > > Thanks, > > - Ted > -- > 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 -- -- 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
