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qemu_saveimage: introduce helpers to decompress memory state file

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These new helpers separates the code from the logic used to start new
QEMU process with memory state and will make it easier to move
qemuSaveImageStartProcess() into qemu_process.c file.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
This commit is contained in:
Pavel Hrdina 2023-09-18 15:13:48 +02:00
parent 71163e78b7
commit df41a1a00f
2 changed files with 128 additions and 42 deletions
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155
src/qemu/qemu_saveimage.c
View File

@ -247,6 +247,116 @@ qemuSaveImageGetCompressionCommand(virQEMUSaveFormat compression)
}
/**
* qemuSaveImageDecompressionStart:
* @data: data from memory state file
* @fd: pointer to FD of memory state file
* @intermediatefd: pointer to FD to store original @fd
* @errbuf: error buffer for @retcmd
* @retcmd: new virCommand pointer
*
* Start process to decompress VM memory state from @fd. If decompression
* is needed the original FD is stored to @intermediatefd and new FD after
* decompression is stored to @fd so caller can use the same variable
* in both cases.
*
* Function qemuSaveImageDecompressionStop() needs to be used to correctly
* stop the process and swap FD to the original state.
*
* Caller is responsible for freeing @retcmd.
*
* Returns -1 on error, 0 on success.
*/
int
qemuSaveImageDecompressionStart(virQEMUSaveData *data,
int *fd,
int *intermediatefd,
char **errbuf,
virCommand **retcmd)
{
virQEMUSaveHeader *header = &data->header;
g_autoptr(virCommand) cmd = NULL;
if (header->version != 2)
return 0;
if (header->compressed == QEMU_SAVE_FORMAT_RAW)
return 0;
if (!(cmd = qemuSaveImageGetCompressionCommand(header->compressed)))
return -1;
*intermediatefd = *fd;
*fd = -1;
virCommandSetInputFD(cmd, *intermediatefd);
virCommandSetOutputFD(cmd, fd);
virCommandSetErrorBuffer(cmd, errbuf);
virCommandDoAsyncIO(cmd);
if (virCommandRunAsync(cmd, NULL) < 0) {
*fd = *intermediatefd;
*intermediatefd = -1;
return -1;
}
*retcmd = g_steal_pointer(&cmd);
return 0;
}
/**
* qemuSaveImageDecompressionStop:
* @cmd: virCommand pointer
* @fd: pointer to FD of memory state file
* @intermediatefd: pointer to FD to store original @fd
* @errbuf: error buffer for @cmd
* @started: boolean to indicate if QEMU process was started
* @path: path to the memory state file
*
* Stop decompression process and close both @fd and @intermediatefd if
* necessary.
*
* Returns -1 on errro, 0 on success.
*/
int
qemuSaveImageDecompressionStop(virCommand *cmd,
int *fd,
int *intermediatefd,
char *errbuf,
bool started,
const char *path)
{
int rc = 0;
virErrorPtr orig_err = NULL;
if (*intermediatefd == -1)
return rc;
if (!started) {
/* if there was an error setting up qemu, the intermediate
* process will wait forever to write to stdout, so we
* must manually kill it and ignore any error related to
* the process
*/
virErrorPreserveLast(&orig_err);
VIR_FORCE_CLOSE(*intermediatefd);
VIR_FORCE_CLOSE(*fd);
}
rc = virCommandWait(cmd, NULL);
VIR_DEBUG("Decompression binary stderr: %s", NULLSTR(errbuf));
virErrorRestore(&orig_err);
if (VIR_CLOSE(*fd) < 0) {
virReportSystemError(errno, _("cannot close file: %1$s"), path);
rc = -1;
}
return rc;
}
/* Helper function to execute a migration to file with a correct save header
* the caller needs to make sure that the processors are stopped and do all other
* actions besides saving memory */
@ -595,7 +705,6 @@ qemuSaveImageStartProcess(virConnectPtr conn,
{
qemuDomainObjPrivate *priv = vm->privateData;
g_autoptr(qemuDomainSaveCookie) cookie = NULL;
virQEMUSaveHeader *header = &data->header;
VIR_AUTOCLOSE intermediatefd = -1;
g_autoptr(virCommand) cmd = NULL;
g_autofree char *errbuf = NULL;
@ -605,25 +714,8 @@ qemuSaveImageStartProcess(virConnectPtr conn,
virDomainXMLOptionGetSaveCookie(driver->xmlopt)) < 0)
return -1;
if ((header->version == 2) &&
(header->compressed != QEMU_SAVE_FORMAT_RAW)) {
if (!(cmd = qemuSaveImageGetCompressionCommand(header->compressed)))
return -1;
intermediatefd = *fd;
*fd = -1;
virCommandSetInputFD(cmd, intermediatefd);
virCommandSetOutputFD(cmd, fd);
virCommandSetErrorBuffer(cmd, &errbuf);
virCommandDoAsyncIO(cmd);
if (virCommandRunAsync(cmd, NULL) < 0) {
*fd = intermediatefd;
intermediatefd = -1;
return -1;
}
}
if (qemuSaveImageDecompressionStart(data, fd, &intermediatefd, &errbuf, &cmd) < 0)
return -1;
/* No cookie means libvirt which saved the domain was too old to mess up
* the CPU definitions.
@ -641,28 +733,7 @@ qemuSaveImageStartProcess(virConnectPtr conn,
start_flags) == 0)
*started = true;
if (intermediatefd != -1) {
virErrorPtr orig_err = NULL;
if (!*started) {
/* if there was an error setting up qemu, the intermediate
* process will wait forever to write to stdout, so we
* must manually kill it and ignore any error related to
* the process
*/
virErrorPreserveLast(&orig_err);
VIR_FORCE_CLOSE(intermediatefd);
VIR_FORCE_CLOSE(*fd);
}
rc = virCommandWait(cmd, NULL);
VIR_DEBUG("Decompression binary stderr: %s", NULLSTR(errbuf));
virErrorRestore(&orig_err);
}
if (VIR_CLOSE(*fd) < 0) {
virReportSystemError(errno, _("cannot close file: %1$s"), path);
rc = -1;
}
rc = qemuSaveImageDecompressionStop(cmd, fd, &intermediatefd, errbuf, *started, path);
virDomainAuditStart(vm, "restored", *started);
if (!*started || rc < 0)

15
src/qemu/qemu_saveimage.h
View File

@ -99,6 +99,21 @@ qemuSaveImageGetCompressionProgram(const char *imageFormat,
bool use_raw_on_fail)
ATTRIBUTE_NONNULL(2);
int
qemuSaveImageDecompressionStart(virQEMUSaveData *data,
int *fd,
int *intermediatefd,
char **errbuf,
virCommand **retcmd);
int
qemuSaveImageDecompressionStop(virCommand *cmd,
int *fd,
int *intermediatefd,
char *errbuf,
bool started,
const char *path);
int
qemuSaveImageCreate(virQEMUDriver *driver,
virDomainObj *vm,