On Mon, Dec 05, 2011 at 10:41:33AM -0500, Ted Ts'o wrote: > (Reviews sent to ext4 list only) > > On Mon, Nov 28, 2011 at 03:26:29PM -0800, Darrick J. Wong wrote: > > This patch introduces a rocompat feature flag to signal the presence > > of checksums for metadata blocks. It also provides storage for a > > precomputed UUID checksum. > > > > + > > + /* Precomputed FS UUID checksum */ > > + __u32 s_uuid_csum; > > This is really a checksum seed, right? Calling it a UUID is going to > be confusing because UUID's are expected to be 128 bits, and something > which is 32 bits can't possibly be a universally unique. It's the checksum of the FS UUID, so I guess 'seed' describes it. I wasn't trying to call it a UUID. I also need to clarify the changelog, apparently. s_uuid_csum is *in-core* storage for a precomputed UUID checksum. This piece (and i_uuid_inum_csum) are computed at load time, just in case the user changed the UUID when the fs was offline. > I'd suggest calling this "s_csum_seed", and we explain it as a > random seed which is selected when the file system is formatted. Not necessarily random, since you can mkfs.ext4 -U. > The commit description could also explain that this is used so we can > detect old metadata blocks left over from a previous use of the > storage device. Ok. --D -- 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
