Valid quorum resources look like
quorum:threshold/total:path/to/image_1: ... :path/to/image_total
':' is used as a separator
'\' is the escaping character for filename containing ':'
'\' escape itself
',' must be escaped with ','
On the command line for quorum files "img:test.raw", "img2,raw"
and "img3.raw" invocation look like:
-drive file=quorum:2/3:img\\:test.raw:img2,,raw:img3.raw
(note the double \\ and the double ,,)
Signed-off-by: Benoit Canet <ben...@irqsave.net>
---
block/quorum.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 122 insertions(+)
diff --git a/block/quorum.c b/block/quorum.c
index 1f12438..c7ecffd 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -52,11 +52,133 @@ struct QuorumAIOCB {
int vote_ret;
};
+/* Valid quorum resources look like
+ * quorum:threshold/total:path/to/image_1: ... :path/to/image_total
+ *
+ * ':' is used as a separator
+ * '\' is the escaping character for filename containing ':'
+ */
+static int quorum_open(BlockDriverState *bs, const char *filename, int flags)
+{
+ BDRVQuorumState *s = bs->opaque;
+ int i, j, k, len, ret = 0;
+ char *a, *b, *names;
+ const char *start;
+ bool escape;
+
+ /* Parse the quorum: prefix */
+ if (!strstart(filename, "quorum:", &start)) {
+ return -EINVAL;
+ }
+
+ /* Get threshold */
+ errno = 0;
+ s->threshold = strtoul(start, &a, 10);
+ if (*a != '/' || errno) {
+ return -EINVAL;
+ }
+ a++;
+
+ /* Get total */
+ errno = 0;
+ s->total = strtoul(a, &b, 10);
+ if (*b != ':' || errno) {
+ return -EINVAL;
+ }
+ b++;
+
+ if (s->threshold < 1 || s->total < 2) {
+ return -EINVAL;
+ }
+
+ if (s->threshold > s->total) {
+ return -EINVAL;
+ }
+
+ s->bs = g_malloc0(sizeof(BlockDriverState *) * s->total);
+ /* Two allocations for all filenames: simpler to free */
+ s->filenames = g_malloc0(sizeof(char *) * s->total);
+ names = g_strdup(b);
+
+ /* Get the filenames pointers */
+ escape = false;
+ s->filenames[0] = names;
+ len = strlen(names);
+ for (i = j = k = 0; i < len && j < s->total; i++) {
+ /* separation between two files */
+ if (!escape && names[i] == ':') {
+ char *prev = s->filenames[j];
+ prev[k] = '\0';
+ s->filenames[++j] = prev + k + 1;
+ k = 0;
+ continue;
+ }
+
+ escape = !escape && names[i] == '\\';
+
+ /* if we are not escaping copy */
+ if (!escape) {
+ s->filenames[j][k++] = names[i];
+ }
+ }
+ /* terminate last string */
+ s->filenames[j][k] = '\0';
+
+ if ((j + 1) != s->total) {
+ ret = -EINVAL;
+ goto free_exit;
+ }
+
+ /* Open files */
+ for (i = 0; i < s->total; i++) {
+ s->bs[i] = bdrv_new("");
+ ret = bdrv_open(s->bs[i], s->filenames[i], flags, NULL);
+ if (ret < 0) {
+ goto error_exit;
+ }
+ }
+
+ goto exit;
+
+error_exit:
+ for (; i >= 0; i--) {
+ bdrv_delete(s->bs[i]);
+ s->bs[i] = NULL;
+ }
+free_exit:
+ g_free(s->filenames[0]);
+ g_free(s->filenames);
+ s->filenames = NULL;
+ g_free(s->bs);
+exit:
+ return ret;
+}
+
+static void quorum_close(BlockDriverState *bs)
+{
+ BDRVQuorumState *s = bs->opaque;
+ int i;
+
+ for (i = 0; i < s->total; i++) {
+ /* Ensure writes reach stable storage */
+ bdrv_flush(s->bs[i]);
+ bdrv_delete(s->bs[i]);
+ }
+
+ g_free(s->filenames[0]);
+ g_free(s->filenames);
+ s->filenames = NULL;
+ g_free(s->bs);
+}
+
static BlockDriver bdrv_quorum = {
.format_name = "quorum",
.protocol_name = "quorum",
.instance_size = sizeof(BDRVQuorumState),
+
+ .bdrv_file_open = quorum_open,
+ .bdrv_close = quorum_close,
};
static void bdrv_quorum_init(void)
--
1.7.10.4
