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This results in contention on those locks which I think can be reduced. The basic strategy is: 1. try to do obvious easy src writeback outside the lock. 2. downgrade the src lock to shared where it is safe. Boris Burkov (3): btrfs: pre-flush reflink source before taking inode locks btrfs: skip unlocked reflink source flush if the inode has writers btrfs: downgrade the reflink source inode lock for tree walking fs/btrfs/btrfs_inode.h | 6 ++++ fs/btrfs/direct-io.c | 7 ++++ fs/btrfs/reflink.c | 72 ++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 83 insertions(+), 2 deletions(-) -- 2.55.0