[PATCH RFC 0/3] xfs: rework quotaoff to avoid log deadlock

[Brian Foster <bfoster@redhat.com>]

Hi all,

Here's an RFC for the quotaoff rework (based on Dave's suggestion) to
incorporate a transaction subsystem quiesce to provide dquot log
ordering guarantees without creating a log deadlock vector. This is RFC
mainly due to patch 2, which was a quick hack to freeze the transaction
subsystem because I wanted to focus on the core approach/algorithm
first. If the general approach is acceptable, I'll go back and implement
something that doesn't abuse an external mechanism for transaction
freeze (perhaps just using a similar, internal percpu rwsem). Patch 1 is
a dependent bug fix to avoid logging dquots for inactive quota modes and
patch 3 reworks quotaoff as described. Thoughts, reviews, flames
appreciated.

Brian

Brian Foster (3):
  xfs: skip dquot reservations if quota is inactive
  xfs: temporary transaction subsystem freeze hack
  xfs: rework quotaoff logging to avoid log deadlock on active fs

 fs/xfs/xfs_qm_syscalls.c | 36 ++++++++++++++++--------------------
 fs/xfs/xfs_trans.c       | 16 ++++++++++++++++
 fs/xfs/xfs_trans.h       |  2 ++
 fs/xfs/xfs_trans_dquot.c | 22 +++++++++++-----------
 4 files changed, 45 insertions(+), 31 deletions(-)

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2.25.4