Hallo, https://btrfs.wiki.kernel.org/index.php/Tree-checker suggested that I ask here for help. When I run a Linux-Kernel 5.7.0-rc2, compiled with pretty much default configuration, and try to run ls /vservers I get the error message: ls: cannot access '/vservers': Input/output error >From dmesg I get: [912737.466820] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [912737.466825] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [912737.467190] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [912737.467194] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected With kernel 5.6.9 I get: [ 520.285953] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.285958] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.286234] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.286238] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.771733] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.771746] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.772075] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.772079] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.778309] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.778314] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.778656] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.778661] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.783287] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.783292] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.783655] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.783659] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.788400] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.788404] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.788745] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.788749] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected [ 520.791619] BTRFS critical (device dm-2): corrupt leaf: root=5 block=350945280 slot=85 ino=55495, unknown flags detected: 0x2000000 [ 520.791624] BTRFS error (device dm-2): block=350945280 read time tree block corruption detected With the default kernel of Debian “Stable” = “10” = “Buster”, which is presently 4.19.0-9 this works flawlessly. When I booted my computer with grml 2018.12 ( https://grml.org/ ) with a 4.19.8 kernel, I didn_t have any problems either, “btrfs check” and “btrfs scrub” didn't find any errors. Has there been a change to tree-checker, that has a problem with something vServer ( http://linux-vserver.org ) does? I don't use vServer any more, since Debian stopped supporting it, I only keep those files for reference. I don't think that matters, but I have three SSDs in a RAID0 Array, on top of which there is a LUKS container which contains a LVM2 which in turn has the BTRFS file system in one of it's LVs. Is there any other information You need? Greeting, Joerg
