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
