block/gluster: add support for selecting debug logging level

This adds commandline support for the logging level of the
gluster protocol driver, output to stdout.  The option is 'debug',
e.g.:

-drive filename=gluster://192.168.15.180/gv2/test.qcow2,debug=9

Debug levels are 0-9, with 9 being the most verbose, and 0 representing
no debugging output.  The default is the same as it was before, which
is a level of 4.  The current logging levels defined in the gluster
source are:

    0 - None
    1 - Emergency
    2 - Alert
    3 - Critical
    4 - Error
    5 - Warning
    6 - Notice
    7 - Info
    8 - Debug
    9 - Trace

(From: glusterfs/logging.h)

Reviewed-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>

block/gluster.c

@@ -25,6 +25,7 @@ typedef struct BDRVGlusterState {
     struct glfs *glfs;
     struct glfs_fd *fd;
     bool supports_seek_data;
+    int debug_level;
 } BDRVGlusterState;
 
 typedef struct GlusterConf {
@@ -33,6 +34,7 @@ typedef struct GlusterConf {
     char *volname;
     char *image;
     char *transport;
+    int debug_level;
 } GlusterConf;
 
 static void qemu_gluster_gconf_free(GlusterConf *gconf)
@@ -195,11 +197,7 @@ static struct glfs *qemu_gluster_init(GlusterConf *gconf, const char *filename,
         goto out;
     }
 
-    /*
-     * TODO: Use GF_LOG_ERROR instead of hard code value of 4 here when
-     * GlusterFS makes GF_LOG_* macros available to libgfapi users.
-     */
-    ret = glfs_set_logging(glfs, "-", 4);
+    ret = glfs_set_logging(glfs, "-", gconf->debug_level);
     if (ret < 0) {
         goto out;
     }
@@ -257,16 +255,26 @@ static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret, void *arg)
     qemu_bh_schedule(acb->bh);
 }
 
+#define GLUSTER_OPT_FILENAME "filename"
+#define GLUSTER_OPT_DEBUG "debug"
+#define GLUSTER_DEBUG_DEFAULT 4
+#define GLUSTER_DEBUG_MAX 9
+
 /* TODO Convert to fine grained options */
 static QemuOptsList runtime_opts = {
     .name = "gluster",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
     .desc = {
         {
-            .name = "filename",
+            .name = GLUSTER_OPT_FILENAME,
             .type = QEMU_OPT_STRING,
             .help = "URL to the gluster image",
         },
+        {
+            .name = GLUSTER_OPT_DEBUG,
+            .type = QEMU_OPT_NUMBER,
+            .help = "Gluster log level, valid range is 0-9",
+        },
         { /* end of list */ }
     },
 };
@@ -329,8 +337,17 @@ static int qemu_gluster_open(BlockDriverState *bs,  QDict *options,
         goto out;
     }
 
-    filename = qemu_opt_get(opts, "filename");
+    filename = qemu_opt_get(opts, GLUSTER_OPT_FILENAME);
 
+    s->debug_level = qemu_opt_get_number(opts, GLUSTER_OPT_DEBUG,
+                                         GLUSTER_DEBUG_DEFAULT);
+    if (s->debug_level < 0) {
+        s->debug_level = 0;
+    } else if (s->debug_level > GLUSTER_DEBUG_MAX) {
+        s->debug_level = GLUSTER_DEBUG_MAX;
+    }
+
+    gconf->debug_level = s->debug_level;
     s->glfs = qemu_gluster_init(gconf, filename, errp);
     if (!s->glfs) {
         ret = -errno;
@@ -388,6 +405,7 @@ static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
                                        BlockReopenQueue *queue, Error **errp)
 {
     int ret = 0;
+    BDRVGlusterState *s;
     BDRVGlusterReopenState *reop_s;
     GlusterConf *gconf = NULL;
     int open_flags = 0;
@@ -395,6 +413,8 @@ static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
     assert(state != NULL);
     assert(state->bs != NULL);
 
+    s = state->bs->opaque;
+
     state->opaque = g_new0(BDRVGlusterReopenState, 1);
     reop_s = state->opaque;
 
@@ -402,6 +422,7 @@ static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
 
     gconf = g_new0(GlusterConf, 1);
 
+    gconf->debug_level = s->debug_level;
     reop_s->glfs = qemu_gluster_init(gconf, state->bs->filename, errp);
     if (reop_s->glfs == NULL) {
         ret = -errno;
@@ -535,6 +556,14 @@ static int qemu_gluster_create(const char *filename,
     char *tmp = NULL;
     GlusterConf *gconf = g_new0(GlusterConf, 1);
 
+    gconf->debug_level = qemu_opt_get_number_del(opts, GLUSTER_OPT_DEBUG,
+                                                 GLUSTER_DEBUG_DEFAULT);
+    if (gconf->debug_level < 0) {
+        gconf->debug_level = 0;
+    } else if (gconf->debug_level > GLUSTER_DEBUG_MAX) {
+        gconf->debug_level = GLUSTER_DEBUG_MAX;
+    }
+
     glfs = qemu_gluster_init(gconf, filename, errp);
     if (!glfs) {
         ret = -errno;
@@ -919,6 +948,11 @@ static QemuOptsList qemu_gluster_create_opts = {
             .type = QEMU_OPT_STRING,
             .help = "Preallocation mode (allowed values: off, full)"
         },
+        {
+            .name = GLUSTER_OPT_DEBUG,
+            .type = QEMU_OPT_NUMBER,
+            .help = "Gluster log level, valid range is 0-9",
+        },
         { /* end of list */ }
     }
 };