On Thu, 2020-07-02 at 04:18 +0200, Marc Lehmann wrote: > > When the server is in this condition, then all btrfs filesystems on > slow > stores (regardless of whether they use dmcache or not) fail their > first > mount attempt(s) like this: > > [ 173.243117] BTRFS info (device dm-7): has skinny extents > [ 864.982108] BTRFS error (device dm-7): open_ctree failed > > all the filesystems in question are mounted twice during normal > boots, > with diferent subvolumes, and systemd parallelises these mounts. This > might > play a role in these failures. > > Simply trying to mount the filesystems again then (usually) succeeds > with > seemingly no issues, so these are spurious mount failures. These > repeated > mount attewmpts are also much faster, presumably because a lot of the > data > is already in memory. You shared kernel logs, but it would be helpful to see the systemd journal. One thing to note is that by default systemd has a timeout on mounts! It's entirely possible that as soon as the mount kernel thread becomes unblocked, it notices that systemd has sent a SIGTERM/SIGKILL and aborts the mount. See the documentation (man systemd.mount) and consider increasing or disabling the timeout on the affected mount units. -- Calvin Walton <calvin.walton@xxxxxxxxxx>
