On 18 May 2018 at 15:56, Eric Sandeen <sandeen@xxxxxxxxxxx> wrote: > On 5/18/18 9:43 AM, Mike Fleetwood wrote: >> >> (Sorry for the late reply, work commitments) >> > ... > >> So after checking, GParted was modified to use the dumpe2fs command to >> read the superblock to get the file system size for mounted ext* file >> systems too. >> >> https://marc.info/?l=linux-ext4&m=134706477618732&w=2 >> >> I see that xfs_db doesn't allow reading the super block of mounted XFS >> file systems. So for the case of a mounted XFS on full fat block device >> I guess I'll wait and see how much overhead is subtracted from the >> statvfs f_blocks figure and make sure GParted accounts for that. > > > Actually you can, with -r: > > # mount /dev/sda1 /mnt/test > # xfs_db -r -c "sb 0" -c "p dblocks" /dev/sda1 > dblocks = 229771264 > > though I may be giving you rope to hang yourself here ;) > > It's generally a bit dicey to be reading a mounted block device for any > filesystem, as there's no coordination with changes the filesystem may > be making while it's mounted. > > The XFS_IOC_FSGEOMETRY would be a better choice for gathering geometry > information for a mounted xfs filesystem. Thanks, the xfs_db -r option is exactly what I need. (Should have checked the man page myself for that). Mike -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
