On Tue, Jun 09, 2009 at 10:46:55AM +0900, Hisashi Hifumi wrote: > Hi. > > I got following BUG trace. > This is violation of BUG_ON(!buffer_locked(bh)) check on submit_bh() function. > In write_dev_supers(), if wait parameter is set and buffer_uptodate() check > is negative, submit_bh() is executed and hit above BUG_ON. > So I fixed this issue. Thanks for finding this bug and sending the patch. This function is very confusing. If wait parameter is set, it isn't supposed to do any IO at all. The caller first does write_dev_supers with wait == 0, and that sends all the supers down on all the devices. Then it calls again with wait == 1, which is supposed to make sure all the supers actually got to disk. We should change the wait == 0 behavior to leave a reference held on all the buffers, and wait == 1 to drop that reference. That way the buffer won't disappear while we are waiting, and we can return an error if the buffer wasn't up to date when wait == 1. Are you interested in fixing this? -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
