[libvirt] [[PATCH v2] 0/4] try harder to get dest qemu errors on migation

Hi, all. In case migration fails due to destination qemu exits unexpectedly user recevies the qemu log in the error message. Unfortunately log is truncated and the most interesting part is missed (below is the example of such a log [1]). Actually for the most cases the first patch will be enough to fix the issue. Originally I thought the problem is qemu logging and reading the log are not in sync (which is true) so I tried to fix it as well in the next patches. * diff from v1: 1. split changes to libvirtd and virtlogd to different patches 2. split virtlogd patch further 3. simplify handling eofs and hangups in draining function [1] log example: CPU Reset (CPU 0) EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000000 ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000 EIP=00000000 EFL=00000000 [-------] CPL=0 II=0 A20=0 SMM=0 HLT=0 ES =0000 00000000 00000000 00000000 CS =0000 00000000 00000000 00000000 SS =0000 00000000 00000000 00000000 DS =0000 00000000 00000000 00000000 FS =0000 00000000 00000000 00000000 GS =0000 00000000 00000000 00000000 LDT=0000 00000000 00000000 00000000 TR =0000 00000000 00000000 00000000 GDT= 00000000 00000000 IDT= 00000000 00000000 CR0=00000000 CR2=00000000 CR3=00000000 CR4=00000000 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 DR6=0000000000000000 DR7=0000000000000000 CCS=00000000 CCD=00000000 CCO=DYNAMIC EFER=0000000000000000 FCW=0000 FSW=0000 [ST=0] FTW=ff MXCSR=00000000 FPR0=0000000000000000 0000 FPR1=0000000000000000 0000 FPR2=0000000000000000 0000 FPR3=0000000000000000 0000 FPR4=0000000000000000 0000 FPR5=0000000000000000 0000 FPR6=0000000000000000 0000 FPR7=0000000000000000 0000 XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000 XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000 XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000 XMM06=00000000000000000000000000000000 XMM07=00000000000000000000000000000000 CPU Reset (CPU 1) EAX=00000000 EBX=00000000 ECX=00000000 EDX=000206a1 ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000 EIP=0000fff0 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0 ES =0000 00000000 0000ffff 00009300 CS =f000 ffff0000 0000ffff 00009b00 SS =0000 00000000 0000ffff 00009300 DS =0000 00000000 0000ffff 00009300 FS =0000 00000000 0000ffff 00009300 GS =0000 00000000 0000ffff 00009300 LDT=0000 00000000 0000ffff 00008200 TR =0000 00000000 0000ffff 00008b00 GDT= 00000000 0000ffff IDT= 00000000 0000ffff CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 DR6=00000000ffff0ff0 DR7=0000000000000400 CCS=00000000 CCD=00000000 CCO=DYNAMIC EFER=0000000000000000 FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80 FPR0=0000000000000000 0000 FPR1=0000000000000000 0000 FPR2=0000000000000000 0000 FPR3=0000000000000000 0000 FPR4=0000000000000000 0000 FPR5=0000000000000000 0000 FPR6=0000000000000000 0000 FPR7=0000000000000000 0000 XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000 XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000 XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000 XMM06=00000000000000000000000000000000 XMM07=000 qemu: terminating on signal 15 from pid 168133 Nikolay Shirokovskiy (4): util: remove 1k limit for error messages virtlogd: stop reading on EOF instead of hangup virtlogd: add flag to wait for log end on read qemu: if virtlogd is used then read log tail correctly src/logging/log_handler.c | 46 ++++++++++++++++++++++++++++++++++++++++------ src/logging/log_protocol.x | 5 +++++ src/qemu/qemu_domain.c | 7 ++++++- src/qemu/qemu_domain.h | 1 + src/qemu/qemu_process.c | 2 ++ src/util/virerror.c | 9 ++++----- 6 files changed, 58 insertions(+), 12 deletions(-) -- 1.8.3.1