On Mon, May 24, 2021 at 11:35:52AM +0100, fdmanana@kernel.org wrote:

From: Filipe Manana <redacted>

This patchset fixes a fsync failure (-EIO) and transaction abort during
a workload for Microsoft's SQL Server running in a Docker container as
reported at:

https://lore.kernel.org/linux-btrfs/93c4600e-5263-5cba-adf0-6f47526e7561@in.tum.de/ (local)

It also adds an optimization for the workload, by removing lots of fsyncs
that trigger the slow code path and replacing them with ones that use the
fast path, reducing the workload's runtime by about -12% on my test box.

Filipe Manana (3):
  btrfs: fix fsync failure and transaction abort after writes to
    prealloc extents
  btrfs: fix misleading and incomplete comment of btrfs_truncate()
  btrfs: don't set the full sync flag when truncation does not touch
    extents

Added to misc-next, thanks. I've marked the first patch for 5.4+. It
applies cleanly up to 4.4 but I'm not sure if this is safe given the
amount of other fixes that are mentioned in the patch and other fsync
related fixes that have been applied.