From: Peter Krempa <[email protected]> The 'sparse' uses a mode in qemu which requires direct access to the file descriptior of the file itself. If we reside on root-squashed NFS the FD from 'virQEMUFileOpenAs' may not actually be a file which would not work with qemu.
Reject such a config with a better error message and add documentation outlining the quirk. Signed-off-by: Peter Krempa <[email protected]> --- src/qemu/qemu_saveimage.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/src/qemu/qemu_saveimage.c b/src/qemu/qemu_saveimage.c index 23922acd51..a3519f8538 100644 --- a/src/qemu/qemu_saveimage.c +++ b/src/qemu/qemu_saveimage.c @@ -423,6 +423,20 @@ qemuSaveImageDecompressionStop(virCommand *cmd, } +/** + * qemuSaveImageCreateFd: + * @vm: domain object + * @path: path to the save image file + * @wrapperFd: filled with helper structure for the virFileWrapper + * @sparse: 'sparse' image format is used for the save image + * @needUnlink: if filled with 'true' a new file was created and needs to be + * removed on failure + * @bypassCache: Don't use cache for the writes of the save image + * + * Opens the save image @path and prepares it for saving of the VM state. + * Returns a file descriptor on succes. The returned FD is a pipe unless @ + * sparse is true in which case it's an fd to a file. + */ static int qemuSaveImageCreateFd(virDomainObj *vm, const char *path, @@ -455,6 +469,16 @@ qemuSaveImageCreateFd(virDomainObj *vm, if (fd < 0) return -1; + /* 'virQEMUFileOpenAs' can return a pipe/socket in case when it needs to bypass + * root-squashed NFS. Since 'sparse' backing format works only with real + * files we need to reject such cases */ + if (sparse && !virFileFDIsRegular(fd)) { + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, + _("path '%1$s' can't be opened directly (without the use of helper proces) which is incompatible with 'sparse' save image"), + path); + return -1; + } + if (qemuSecuritySetImageFDLabel(priv->driver->securityManager, vm->def, fd) < 0) return -1; -- 2.53.0
