[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [libvirt] [PATCH 3/4] Fix QEMU save/restore with block devices



On 04/21/2010 10:56 AM, Daniel P. Berrange wrote:
> The save process was relying on use of the shell >> append
> operator to ensure the save data was placed after the libvirt
> header + XML. This doesn't work for block devices though.
> Replace this code with use of 'dd' and its 'seek' parameter.
> 
> The qemuMonitorMigateToCommand() monitor API is used for both
> save/coredump, and migration via UNIX socket. We can't simply
> switch this to use 'dd' since this causes problems with the
> migration usage. Thus, create a dedicated qemuMonitorMigateToFile
> which can accept an filename + offset, and remove the filename
> from the current qemuMonitorMigateToCommand() API
> 

> +++ b/src/qemu/qemu_driver.c
> @@ -4789,6 +4789,7 @@ static int qemudDomainSaveFlag(virDomainPtr dom, const char *path,
>      qemuDomainObjPrivatePtr priv;
>      struct stat sb;
>      int is_bdev = 0;
> +    unsigned long long offset;

Should this be off_t instead of ull?

> @@ -1673,7 +1701,8 @@ int qemuMonitorJSONMigrateToCommand(qemuMonitorPtr mon,
>          goto cleanup;
>      }
>  
> -    if (virAsprintf(&dest, "exec:%s >>%s 2>/dev/null", argstr, safe_target) < 0) {
> +    if (virAsprintf(&dest, "exec:%s | dd of=%s seek=%llub",
> +                    argstr, safe_target, offset) < 0) {

Don't you still need to silence stderr, particularly since dd writes to
stderr even on success? (2 instances)

-- 
Eric Blake   eblake redhat com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

Attachment: signature.asc
Description: OpenPGP digital signature


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]