[PATCH 0/4] btrfs: squota lifetime fixes

[Boris Burkov <boris@bur.io>]

A recent report of read-only filesystems since enabling squotas:

https://lore.kernel.org/linux-btrfs/adnBhWfJQ1n3hZC8@merlins.org/

led me to investigate a handful of issues in squotas and find some trivial and
not so trivial bugs in their lifetime management. The aim of the series is to
strengthen enforcement of the invariant: "a squota qgroup must outlast extents
that are accounted to it".

This series consists of two fixes to squota lifetime bugs and two patches that
reduce the consequences of errors in lifetime management from full fs goes
read-only abort to "warning and inaccurate squotas which can be deleted
eventually"

Additional improvements to btrfs check and fstests to follow.

Boris Burkov (4):
  btrfs: check for subvolume before deleting squota qgroup
  btrfs: fix squota accounting during enable generation
  btrfs: clamp to avoid squota underflow
  btrfs: swallow btrfs_record_squota_delta() enoent

 fs/btrfs/fs.h     |  1 +
 fs/btrfs/qgroup.c | 99 ++++++++++++++++++++++++++++++++---------------
 2 files changed, 68 insertions(+), 32 deletions(-)

-- 
2.54.0