On Wed, May 29, 2013 at 04:43:01PM -0500, Ben Myers wrote: > Hi Eric, > > On Wed, May 29, 2013 at 10:10:13AM -0500, Eric Sandeen wrote: > > On 5/27/13 1:38 AM, Dave Chinner wrote: > > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > > > Currently userspace has no way of determining that a filesystem is > > > CRC enabled. Add a flag to the XFS_IOC_FSGEOMETRY ioctl output to > > > indicate that the filesystem has v5 superblock support enabled. > > > This will allow xfs_info to correctly report the state of the > > > filesystem. > > > > > > Looks fine, > > > > Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx> > > > > Ben, having this in place for for the next point release will let > > userspace work & testing proceed w/o the need for a patched > > kernel... if you could consider pulling it in that'd be great. > > Sounds reasonable. I'll check it out. > > > Dave, just out of curiosity, most other features sort of match between > > the "_has_*" and the flag names, is there a reason for the > > crc <-> sbv5 difference? Just semantics, but just curious. > > > > (i.e. xfs_sb_version_hasprojid32bit checks XFS_SB_VERSION2_PROJID32BIT, > > but xfs_sb_version_hascrc checks XFS_SB_VERSION_5) > > > > Answering my own question maybe, I guess SB_VERSION_5 was conceived > > with crc already in place, so there's no need for a feature flag on > > top of the sb version, right...? > > Seems like we're also out of space in xfs_fsop_geom.flags. Nowhere near it, actually ;). flags is a __u32, this is only the 16th flag. > There may even be > people who prefer to use v5 super blocks without crcs turned on, so maybe > conflating the two ideas here is undesireable. The flag is indicating that there is a different format on disk, not that crcs are enabled or not. Userspace needs to know about that different format, and right now *userspace* assumes v5 superblocks mean CRCs are enabled because that's part of the definition of the features that a v5 superblock has. If in future that changes (hint: it won't) then we can add a separate flag to indicate whether CRCs are enabled or not when the feature flag to disable them is added to the superblock. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
