[PATCH 0/3] block/nbd: fix crashers in reconnect while migrating

[Roman Kagan]

During the final phase of migration the NBD reconnection logic may
encounter situations it doesn't expect during regular operation.

This series addresses some of them that make qemu crash.  They are
reproducible when a vm with a secondary drive attached via nbd with
non-zero "reconnect-delay" runs a stress load (fio with big queue depth)
in the guest on that drive and is migrated (e.g. to a file), while the
nbd server is SIGKILL-ed and restarted every second.

See the individual patches for specific crash conditions and more
detailed explanations.

Roman Kagan (3):
  block/nbd: only detach existing iochannel from aio_context
  block/nbd: only enter connection coroutine if it's present
  nbd: make nbd_read* return -EIO on error

 include/block/nbd.h |  7 ++++---
 block/nbd.c         | 25 +++++++++++++++++--------
 2 files changed, 21 insertions(+), 11 deletions(-)

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2.29.2