I don't expect accurate data on a btrfs file system when using df, but after upgrading to kernel 4.4.0 I get the following:
$ df -i ... /dev/sdc3 0 0 0 - /home /dev/sdc4 0 0 0 - /vm0 ... Where /dev/sdc3 and /dev/sdc4 are btrfs filesystems. So is this a bug or not? I ask because root (/dev/sdc3) began to display the error message "no space left on device", which was eventually cured by deleting old snapshots then btrfs fi sync and btrfs balance. fi show and fi df show space, even when df -i shows 0 inodes: sudo btrfs fi show / ... Label: none uuid: 9acdb642-d743-4c2a-a59f-811022c2a2b0 Total devices 1 FS bytes used 23.86GiB devid 1 size 60.00GiB used 42.03GiB path /dev/sdc3 sudo btrfs fi df / Data, single: total=37.00GiB, used=21.11GiB System, single: total=32.00MiB, used=16.00KiB Metadata, single: total=5.00GiB, used=2.75GiB unknown, single: total=512.00MiB, used=0.00 Please excuse my inexperience here; I don't know how to use btrfs commands to show inodes. btrfs inspect-internal will reference an inode as near as I can tell, but won't list the used and free inodes ("free" may not be the correct word here, given btrfs architecture). Many Thanks, Gordon Machine Specs: % uname -a Linux Bon-E 4.4.0-36-generic #55~14.04.1-Ubuntu SMP Fri Aug 12 11:49:30 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux % btrfs --version Btrfs v3.12 % sudo btrfs fi show Label: none uuid: 9acdb642-d743-4c2a-a59f-811022c2a2b0 Total devices 1 FS bytes used 23.86GiB devid 1 size 60.00GiB used 42.03GiB path /dev/sdc3 %Label: vm0 uuid: 72539416-d30e-4a34-8b2d-b2369d1fb075 Total devices 1 FS bytes used 349.96GiB devid 1 size 374.66GiB used 374.66GiB path /dev/sdc4 dmesg does not appear to show anything useful for btrfs or device, but mount shows: % mount | grep btrfs /dev/sdc3 on / type btrfs (rw,ssd,subvol=@) /dev/sdc3 on /home type btrfs (rw,ssd,subvol=@home) /dev/sdc4 on /vm0 type btrfs (rw,ssd,space_cache,compress=lzo,subvol=@vm0) /dev/sdc3 on /mnt/btrfs-root type btrfs (rw) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html