On Thu, Dec 25, 2008 at 10:00:05PM -0200, Alberto Bertogli wrote: > > I think I'm not explaining myself correctly. My code has _nothing_ to do > with ext2/3/4 (or any other filesystem) whatsoever. I'm not using the > journal as an external one for a filesystem. I want to use it to be able > to do atomic writes in my own, filesystem independant, device-mapper > code. How many block writes are you batching into a single transaction? If you're not careful you may find that performance overhead will be quite expensive. > After what you told me (both this and the deprecation of > jbd2_journal_create()), I took a look at e2fsprogs' source. From what I > could see, "mke2fs -O journal_dev" creates the external journal inside > some ext2/3/4 structures, which caused my journal-loading code to fail > (because it doesn't know about ext stuff). Yes, this is necessary because in a production system you need to be able to identify the external journal by UUID, and the ext2/3/4 superblock makes it easy to add a label, UUID, et. al. It also significantly lowers the chance that an external journal will get misidentified as some other filesystem based on the data stored in the journal. - 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
