Re: [libvirt] [PATCHv2 11/15] blockjob: implement block copy for qemu

On 04/06/2012 09:36 AM, Eric Blake wrote: I'm still testing this, but this is probably what I will add as 11.5/15 in my v3 series for allowing the REUSE_EXT flag. From 804c1b654af7f4dddbd3dd768cce7c041436b761 Mon Sep 17 00:00:00 2001 From: Eric Blake <eblake(a)redhat.com&gt; Date: Fri, 6 Apr 2012 10:32:07 -0600 Subject: [PATCH] blockjob: allow for existing files This copies some of the checks from snapshots regarding testing when a file already exists. * src/qemu/qemu_driver.c (qemuDomainBlockRebase): Allow REUSE_EXT flag. (qemuDomainBlockCopy): Wire up flag, and add some sanity checks. --- src/qemu/qemu_driver.c | 51 ++++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 45 insertions(+), 6 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 1b1c921..f7b2a01 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -11881,9 +11881,11 @@ qemuDomainBlockCopy(virDomainPtr dom, const char *path, int ret = -1; int idx; int mode; + struct stat st; /* Preliminaries: find the disk we are editing, sanity checks */ - virCheckFlags(VIR_DOMAIN_BLOCK_REBASE_SHALLOW, -1); + virCheckFlags(VIR_DOMAIN_BLOCK_REBASE_SHALLOW | + VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT, -1); qemuDriverLock(driver); virUUIDFormat(dom->uuid, uuidstr); @@ -11928,19 +11930,55 @@ qemuDomainBlockCopy(virDomainPtr dom, const char *path, goto endjob; } + if ((flags & VIR_DOMAIN_BLOCK_REBASE_SHALLOW) && + STREQ_NULLABLE(format, "raw") && + STRNEQ_NULLABLE(disk->driverType, "raw")) { + qemuReportError(VIR_ERR_INVALID_ARG, + _("raw shallow copy of non-raw disk '%s' not possible"), + disk->dst); + goto endjob; + } + /* XXX this is pessimistic; we could use 'query-block' or even + * keep track of the backing chain ourselves, rather than assuming + * that all non-raw source files have a current backing image */ + if ((flags & VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT) && + !(flags & VIR_DOMAIN_BLOCK_REBASE_SHALLOW) && + STRNEQ_NULLABLE(disk->driverType, "raw")) { + qemuReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, + _("non-shallow copy of non-raw disk '%s' to existing " + "destination not supported"), + disk->dst); + goto endjob; + } + /* Prepare the destination file. */ + if (stat(dest, &st) < 0) { + if (errno != ENOENT) { + virReportSystemError(errno, _("unable to stat for disk %s: %s"), + disk->dst, dest); + goto endjob; + } + } else if (!(S_ISBLK(st.st_mode) || !st.st_size || + (flags & VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT))) { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("external destination file for disk %s already " + "exists and is not a block device: %s"), + disk->dst, dest); + goto endjob; + } + /* XXX We also need to add security labeling, lock manager lease, - * and auditing of those events, as well as to support reuse of - * existing images, including probing the existing format of an - * existing image. */ - if (!format) + * and auditing of those events. */ + if (!format && !(flags & VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT)) format = disk->driverType; if ((format && !(disk->mirrorFormat = strdup(format))) || !(disk->mirror = strdup(dest))) { virReportOOMError(); goto endjob; } - if (flags & VIR_DOMAIN_BLOCK_REBASE_SHALLOW) + if (flags & VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT) + mode = QEMU_MONITOR_DRIVE_MIRROR_EXISTING; + else if (flags & VIR_DOMAIN_BLOCK_REBASE_SHALLOW) mode = QEMU_MONITOR_DRIVE_MIRROR_ABSOLUTE; else mode = QEMU_MONITOR_DRIVE_MIRROR_NO_BACKING; @@ -11976,6 +12014,7 @@ qemuDomainBlockRebase(virDomainPtr dom, const char *path, const char *base, unsigned long bandwidth, unsigned int flags) { virCheckFlags(VIR_DOMAIN_BLOCK_REBASE_SHALLOW | + VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT | VIR_DOMAIN_BLOCK_REBASE_COPY | VIR_DOMAIN_BLOCK_REBASE_COPY_RAW, -1); -- 1.7.7.6 -- Eric Blake eblake(a)redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org