Re: read-only fs, kernel 4.9.0, fs/btrfs/delayed-inode.c:1170 __btrfs_run_delayed_items,

[Omar Sandoval <osandov@osandov.com>]

On Tue, Jan 24, 2017 at 01:48:12PM -0700, Chris Murphy wrote:
> journal_debug.log booted with patched kernel and params
> systemd.log_level=debug rd.debug, and then output to file with
> journalctl -b -o short-monotonic
> https://drive.google.com/open?id=0B_2Asp8DGjJ9MjRDWi0tZ0x4V2s
> 
> I'm uncertain of the immediacy of some event resulting in another but...
> 
> 
> [    8.159581] f25h systemd-tmpfiles[720]: Running create action for
> entry d /var/run/pptp
> [    8.159703] f25h systemd-tmpfiles[720]: Created directory "/var/run/pptp".
> [    8.159825] f25h systemd-tmpfiles[720]: "/var/run/pptp" has right mode 40750
> [    8.159944] f25h systemd-tmpfiles[720]: Running remove action for
> entry d /var/run/pptp
> [    8.160070] f25h systemd-tmpfiles[720]: Running create action for
> entry d /var/run/radvd
> [    8.160186] f25h systemd-tmpfiles[720]: Created directory "/var/run/radvd".
> [    8.160312] f25h systemd-tmpfiles[720]: "/var/run/radvd" has right mode 40755
> [    8.171770] f25h kernel: ------------[ cut here ]------------
> [    8.174028] f25h kernel: WARNING: CPU: 2 PID: 720 at
> fs/btrfs/delayed-inode.c:55
> btrfs_get_or_create_delayed_node+0x16a/0x1e0 [btrfs]
> [    8.176316] f25h kernel: ino 2 is out of range
> 
> 
> Is it the creation of these directories triggering the error? Anyway,
> there's a bunch of systemd-tmpfiles activity prior to this, and right
> before the btrfs_get_or_create_delayed_node call trace.
> 
> 
> The final call trace is cut off, I guess when systemd switches from
> /run to /var and flushes, if the fs goes read only and can't write all
> of what's flushed, it results in journal data loss. If the rest of the
> output is useful I can switch systemd to only use volatile storage to
> avoid this problem.

Got this to repro after installing systemd-container. It's happening on
lsetxattr() to set the SELinux context on /var/lib/machines, which is a
subvolume. Looking into it now. Thanks for all of the help, Chris.