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qemu-img: Add --backing-chain option to info command 

The qemu-img info --backing-chain option enumerates the backing file
chain.  For example, for base.qcow2 <- snap1.qcow2 <- snap2.qcow2 the
output becomes:

  $ qemu-img info --backing-chain snap2.qcow2
  image: snap2.qcow2
  file format: qcow2
  virtual size: 100M (104857600 bytes)
  disk size: 196K
  cluster_size: 65536
  backing file: snap1.qcow2
  backing file format: qcow2

  image: snap1.qcow2
  file format: qcow2
  virtual size: 100M (104857600 bytes)
  disk size: 196K
  cluster_size: 65536
  backing file: base.qcow2
  backing file format: qcow2

  image: base.qcow2
  file format: qcow2
  virtual size: 100M (104857600 bytes)
  disk size: 136K
  cluster_size: 65536

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2012-10-17 14:02:31 +02:00 committed by Kevin Wolf
parent 6bf0d1f478
commit 9699bf0d06
1 changed files with 153 additions and 14 deletions
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167
qemu-img.c
View File

@ -1112,6 +1112,23 @@ static void dump_snapshots(BlockDriverState *bs)
g_free(sn_tab);
}
static void dump_json_image_info_list(ImageInfoList *list)
{
Error *errp = NULL;
QString *str;
QmpOutputVisitor *ov = qmp_output_visitor_new();
QObject *obj;
visit_type_ImageInfoList(qmp_output_get_visitor(ov),
&list, NULL, &errp);
obj = qmp_output_get_qobject(ov);
str = qobject_to_json_pretty(obj);
assert(str != NULL);
printf("%s\n", qstring_get_str(str));
qobject_decref(obj);
qmp_output_visitor_cleanup(ov);
QDECREF(str);
}
static void collect_snapshots(BlockDriverState *bs , ImageInfo *info)
{
int i, sn_count;
@ -1251,9 +1268,129 @@ static void dump_human_image_info(ImageInfo *info)
printf("backing file format: %s\n", info->backing_filename_format);
}
}
if (info->has_snapshots) {
SnapshotInfoList *elem;
char buf[256];
printf("Snapshot list:\n");
printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
/* Ideally bdrv_snapshot_dump() would operate on SnapshotInfoList but
* we convert to the block layer's native QEMUSnapshotInfo for now.
*/
for (elem = info->snapshots; elem; elem = elem->next) {
QEMUSnapshotInfo sn = {
.vm_state_size = elem->value->vm_state_size,
.date_sec = elem->value->date_sec,
.date_nsec = elem->value->date_nsec,
.vm_clock_nsec = elem->value->vm_clock_sec * 1000000000ULL +
elem->value->vm_clock_nsec,
};
pstrcpy(sn.id_str, sizeof(sn.id_str), elem->value->id);
pstrcpy(sn.name, sizeof(sn.name), elem->value->name);
printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), &sn));
}
}
}
enum {OPTION_OUTPUT = 256};
static void dump_human_image_info_list(ImageInfoList *list)
{
ImageInfoList *elem;
bool delim = false;
for (elem = list; elem; elem = elem->next) {
if (delim) {
printf("\n");
}
delim = true;
dump_human_image_info(elem->value);
}
}
static gboolean str_equal_func(gconstpointer a, gconstpointer b)
{
return strcmp(a, b) == 0;
}
/**
* Open an image file chain and return an ImageInfoList
*
* @filename: topmost image filename
* @fmt: topmost image format (may be NULL to autodetect)
* @chain: true - enumerate entire backing file chain
* false - only topmost image file
*
* Returns a list of ImageInfo objects or NULL if there was an error opening an
* image file. If there was an error a message will have been printed to
* stderr.
*/
static ImageInfoList *collect_image_info_list(const char *filename,
const char *fmt,
bool chain)
{
ImageInfoList *head = NULL;
ImageInfoList **last = &head;
GHashTable *filenames;
filenames = g_hash_table_new_full(g_str_hash, str_equal_func, NULL, NULL);
while (filename) {
BlockDriverState *bs;
ImageInfo *info;
ImageInfoList *elem;
if (g_hash_table_lookup_extended(filenames, filename, NULL, NULL)) {
error_report("Backing file '%s' creates an infinite loop.",
filename);
goto err;
}
g_hash_table_insert(filenames, (gpointer)filename, NULL);
bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING,
false);
if (!bs) {
goto err;
}
info = g_new0(ImageInfo, 1);
collect_image_info(bs, info, filename, fmt);
collect_snapshots(bs, info);
elem = g_new0(ImageInfoList, 1);
elem->value = info;
*last = elem;
last = &elem->next;
bdrv_delete(bs);
filename = fmt = NULL;
if (chain) {
if (info->has_full_backing_filename) {
filename = info->full_backing_filename;
} else if (info->has_backing_filename) {
filename = info->backing_filename;
}
if (info->has_backing_filename_format) {
fmt = info->backing_filename_format;
}
}
}
g_hash_table_destroy(filenames);
return head;
err:
qapi_free_ImageInfoList(head);
g_hash_table_destroy(filenames);
return NULL;
}
enum {
OPTION_OUTPUT = 256,
OPTION_BACKING_CHAIN = 257,
};
typedef enum OutputFormat {
OFORMAT_JSON,
@ -1264,9 +1401,9 @@ static int img_info(int argc, char **argv)
{
int c;
OutputFormat output_format = OFORMAT_HUMAN;
bool chain = false;
const char *filename, *fmt, *output;
BlockDriverState *bs;
ImageInfo *info;
ImageInfoList *list;
fmt = NULL;
output = NULL;
@ -1276,6 +1413,7 @@ static int img_info(int argc, char **argv)
{"help", no_argument, 0, 'h'},
{"format", required_argument, 0, 'f'},
{"output", required_argument, 0, OPTION_OUTPUT},
{"backing-chain", no_argument, 0, OPTION_BACKING_CHAIN},
{0, 0, 0, 0}
};
c = getopt_long(argc, argv, "f:h",
@ -1294,6 +1432,9 @@ static int img_info(int argc, char **argv)
case OPTION_OUTPUT:
output = optarg;
break;
case OPTION_BACKING_CHAIN:
chain = true;
break;
}
}
if (optind >= argc) {
@ -1310,27 +1451,25 @@ static int img_info(int argc, char **argv)
return 1;
}
bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING, false);
if (!bs) {
list = collect_image_info_list(filename, fmt, chain);
if (!list) {
return 1;
}
info = g_new0(ImageInfo, 1);
collect_image_info(bs, info, filename, fmt);
switch (output_format) {
case OFORMAT_HUMAN:
dump_human_image_info(info);
dump_snapshots(bs);
dump_human_image_info_list(list);
break;
case OFORMAT_JSON:
collect_snapshots(bs, info);
dump_json_image_info(info);
if (chain) {
dump_json_image_info_list(list);
} else {
dump_json_image_info(list->value);
}
break;
}
qapi_free_ImageInfo(info);
bdrv_delete(bs);
qapi_free_ImageInfoList(list);
return 0;
}