There are severe delays with IO requests processing if QEMU is running in virtual machine or over software defined storage. Such delays potentially results in unpredictable guest behavior. For example, guests over IDE or SATA drive could remount filesystem read-only if write is performed longer than 10 seconds.
Such reports are very complex to process. Some good starting point for this seems quite reasonable. This patch provides one. It adds logging of such potentially dangerous long IO operations. Signed-off-by: Denis V. Lunev <d...@openvz.org> CC: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> CC: Kevin Wolf <kw...@redhat.com> CC: Max Reitz <mre...@redhat.com>
