Package: btrfs-progs Version: 4.7.3-1 Severity: normal First I don't know if this is a btrfs-progs error or a kernel error. But when in doubt it seems most reasonable to file against btrfs-progs to get the attention of someone who can help work this out. Even if the kernel is doing the wrong thing the utility should be able to be more helpful in it's error messages.
# btrfs replace start -B 3 /dev/sdd2 / ERROR: ioctl(DEV_REPLACE_START) on '/' returns error: <illegal result value> # btrfs replace start -B /dev/sdb2 /dev/sdd2 / ERROR: ioctl(DEV_REPLACE_START) on '/' returns error: <illegal result value> # btrfs replace start -B /dev/sdc2 /dev/sdd2 / ERROR: ioctl(DEV_REPLACE_START) on '/' returns error: <illegal result value> # btrfs replace start -B 1 /dev/sdd2 / ERROR: ioctl(DEV_REPLACE_START) on '/' returns error: <illegal result value> The above is the result of some routine device replacement commands. # btrfs device usage / /dev/sda2, ID: 2 Device size: 446.67GiB Device slack: 0.00B Data,RAID1: 329.40GiB Metadata,RAID1: 5.00GiB System,RAID1: 32.00MiB Unallocated: 112.24GiB /dev/sdb2, ID: 3 Device size: 111.32GiB Device slack: 0.00B Data,RAID1: 111.32GiB Unallocated: 1.02MiB /dev/sdc2, ID: 1 Device size: 223.10GiB Device slack: 0.00B Data,RAID1: 218.07GiB Metadata,RAID1: 5.00GiB System,RAID1: 32.00MiB Unallocated: 1.02MiB >From the above you can see that IDs 3 and 1 and devices /dev/sdb2 and /dev/sdc2 are part of the filesystem and suitable for replacement. https://btrfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices#Replacing_failed_devices btrfs-replace(8) and the above Wiki page both indicate that what I am attempting is correct. -- System Information: Debian Release: 9.0 APT prefers stable APT policy: (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 4.9.0-3-amd64 (SMP w/8 CPU cores) Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_AU:en (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages btrfs-progs depends on: ii e2fslibs 1.43.4-2 ii libblkid1 2.29.2-1 ii libc6 2.24-11+deb9u1 ii libcomerr2 1.43.4-2 ii liblzo2-2 2.08-1.2+b2 ii libuuid1 2.29.2-1 ii zlib1g 1:1.2.8.dfsg-5 btrfs-progs recommends no packages. btrfs-progs suggests no packages. -- no debconf information
