Re: [libvirt] [PATCHv4 13/18] blockjob: allow for existing files

This copies some of the checks from snapshots regarding testing when a file already exists. In the process, I noticed a missing sanity check in snapshots: REUSE_EXT should require the destination to already be present. * src/qemu/qemu_driver.c (qemuDomainBlockRebase): Allow REUSE_EXT flag. (qemuDomainBlockCopy): Wire up flag, and add some sanity checks. (qemuDomainSnapshotDiskPrepare): Require destination on REUSE_EXT. --- src/qemu/qemu_driver.c | 48 +++++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 43 insertions(+), 5 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 6d5a5da..661ccb4 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -9812,6 +9812,11 @@ qemuDomainSnapshotDiskPrepare(virDomainObjPtr vm, virDomainSnapshotDefPtr def, _("unable to stat for disk %s: %s"), disk->name, disk->file); goto cleanup; + } else if (allow_reuse) { + virReportSystemError(errno, + _("missing existing file for disk %s: %s"), + disk->name, disk->file); + goto cleanup; } } else if (!(S_ISBLK(st.st_mode) || !st.st_size || allow_reuse)) { qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, @@ -11889,9 +11894,11 @@ qemuDomainBlockCopy(virDomainPtr dom, const char *path, virDomainDiskDefPtr disk; int ret = -1; int idx; + 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); @@ -11936,12 +11943,42 @@ qemuDomainBlockCopy(virDomainPtr dom, const char *path, 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_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; + } + /* 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 (flags & VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT) { + virReportSystemError(errno, + _("missing destination file 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))) { @@ -11980,6 +12017,7 @@ 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);