On 6/7/16 5:51 AM, Emmanuel Florac wrote: > Hi all, > > as you know kernel prior to 3.16 won't support properly v5 superblocks. > xfsprogs v 3.2.4 and higher defaults to v5 superblocks. This bit quite > a lot of people a year ago or so, when some distributions shipped 3.2.4 > xfsprogs with older kernels. > > Anyway, I was surprised to find no easy way to find out the superblock > version of an xfs FS. The best I've come across is > > xfs_db /dev/this > sb > p > > <snip> > versionnum = 0xb4a5 > </snip> There is certainly some confusion about naming. Version 5, compat/incompat features, feature bits, feature names, etc. > So I suppose that the 5 in the end means that the superblock is v5? Can > anyone confirm please? The man page still pretends that the last number > should be 1 to 4, which is confusing. Yes, the last bits contain the version number (masked by 0xf, see below) #define XFS_SB_VERSION_1 1 /* 5.3, 6.0.1, 6.1 */ #define XFS_SB_VERSION_2 2 /* 6.2 - attributes */ #define XFS_SB_VERSION_3 3 /* 6.2 - new inode version */ #define XFS_SB_VERSION_4 4 /* 6.2+ - bitmask version */ #define XFS_SB_VERSION_5 5 /* CRC enabled filesystem */ #define XFS_SB_VERSION_NUMBITS 0x000f feel free to send a man page patch :) > Oh by the way I think the trick to create a v4 filesystem with mkfs.xfs > higher than 3.2.4 ( mkfs.xfs -m crc=0,finobt=0 /dev/this ) should be in > the FAQ, with a line like this: > > Mounting the filesystem fails, and output from dmesg says "Version 5 > superblock detected." What should I do? > > v5 superblocks require a kernel v3.16 of higher. If you need your > xfs filesystem to be usable with older kernel, use the following > options to mkfs.xfs : > > mkfs.xfs -m crc=0,finobt=0 /dev/this finobt=0 should not be needed, it should be off if crc=0 AFAIK. However, -n ftype=1 may still be enabled, and older kernels may have an issue with that as well. Feel free to add this to the wiki (can new accounts still be created?) -Eric _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
