[Qemu-devel] [RFC V3 3/9] quorum: Add quorum_open() and quorum_close().

["Benoît Canet" <benoit.canet@gmail.com>]

Signed-off-by: Benoit Canet <benoit@irqsave.net>
---
 block/quorum.c |  113 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)

diff --git a/block/quorum.c b/block/quorum.c
index bab6175..f228428 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -52,11 +52,124 @@ struct QuorumAIOCB {
     int vote_ret;
 };
 
+/* Valid quorum filenames look like
+ * quorum:n/m:path/to/image_1, ... ,path/to/image_m
+ */
+static int quorum_open(BlockDriverState *bs, const char *filename, int flags)
+{
+    BDRVQuorumState *s = bs->opaque;
+    int escape, i, j, len, ret = 0;
+    char *a, *b, *names;
+
+    /* Parse the quorum: prefix */
+    if (strncmp(filename, "quorum:", strlen("quorum:"))) {
+        return -EINVAL;
+    }
+
+    filename += strlen("quorum:");
+
+    /* Get n */
+    errno = 0;
+    s->n = strtoul(filename, &a, 10);
+    if (*a != '/' || errno) {
+        return -EINVAL;
+    }
+    a += 1;
+
+    /* Get m */
+    errno = 0;
+    s->m = strtoul(a, &b, 10);
+    if (*b != ':' || errno) {
+        return -EINVAL;
+    }
+    b += 1;
+
+    if (s->n < 1 || s->m < 2) {
+        return -EINVAL;
+    }
+
+    if (s->n > s->m) {
+        return -EINVAL;
+    }
+
+    s->bs = g_malloc0(sizeof(BlockDriverState *) * s->m);
+    /* Two allocations for all filenames: simpler to free */
+    s->filenames = g_malloc0(sizeof(char *) * s->m);
+    names = g_strdup(b);
+
+    /* Get the filenames pointers */
+    escape = 0;
+    s->filenames[0] = names;
+    len = strlen(names);
+    for (i = 0, j = 1; i < len && j < s->m; i++) {
+        if (!escape && names[i] == ':') {
+            names[i] = '\0';
+            s->filenames[j] = names + i + 1;
+            j += 1;
+        }
+
+        if (!escape && names[i] == '\\') {
+            escape = 1;
+        } else {
+            escape = 0;
+        }
+    }
+
+    if (j != s->m) {
+        ret = -EINVAL;
+        goto free_exit;
+    }
+
+    /* Open files */
+    for (i = 0; i < s->m; 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->m; 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)
-- 
1.7.9.5