[Qemu-devel] [PATCH v2 0/7] blkdebug

[Kevin Wolf <kwolf@redhat.com>]

This patch series introduces a new block driver which acts as a protocol and
whose purpose it is to fail requests. To be more precise, I want it to fail in
configurable places, so that qemu-iotests can be extended with tests for the
error paths (for example for the case when something with metadata writes goes
wrong deep in qcow2).

It works like this (I think this is self-explanatory):

$ cat /tmp/blkdebug.cfg
[inject-error]
event = "l1_update"
errno = "5"
immediately = "on"
$ qemu-io blkdebug:/tmp/blkdebug.cfg:/tmp/empty.qcow2
qemu-io> read 0 4k
read 4096/4096 bytes at offset 0
4 KiB, 1 ops; 0.0000 sec (195.312 MiB/sec and 50000.0000 ops/sec)
qemu-io> write 0 4k
write failed: Input/output error

Changes in comparison to the RFC:
- Had to rebase qemu-config changes
- Code cleanup (including resolving TODOs and FIXMEs)
- More events all over qcow2
- No debug messages on stderr any more

v2:
- Another rebase
- Fixed memleak in blkdebug_open

Kevin Wolf (7):
  qemu-config: qemu_read_config_file() reads the normal config file
  qemu-config: Make qemu_config_parse more generic
  blkdebug: Basic request passthrough
  blkdebug: Inject errors
  Make qemu-config available for tools
  blkdebug: Add events and rules
  qcow2: Trigger blkdebug events

 Makefile.objs          |    6 +-
 block.c                |   12 ++
 block.h                |   53 ++++++
 block/blkdebug.c       |  475 ++++++++++++++++++++++++++++++++++++++++++++++++
 block/qcow2-cluster.c  |   15 ++
 block/qcow2-refcount.c |   18 ++
 block/qcow2.c          |    6 +
 block_int.h            |    2 +
 hw/qdev-properties.c   |   19 ++-
 hw/qdev.h              |    1 -
 qemu-config.c          |   48 +++---
 qemu-config.h          |    4 +-
 vl.c                   |   38 ++---
 13 files changed, 644 insertions(+), 53 deletions(-)
 create mode 100644 block/blkdebug.c