[Xen-devel] [PATCH 14 of 21] blktap3/drivers: Introduce core tapdisk server

[Thanos Makatos <thanos.makatos@xxxxxxxxxx>]

This patch copies from blktap2 the core of the tapdisk process, with most
changes coming from blktap2.5. Also, it replaces the minor number with
type:/path/to/file in function tapdisk_server_get_vbd as there is no minor
number in blktap3.

Signed-off-by: Thanos Makatos <thanos.makatos@xxxxxxxxxx>

diff --git a/tools/blktap2/drivers/tapdisk-server.c 
b/tools/blktap3/drivers/tapdisk-server.c
copy from tools/blktap2/drivers/tapdisk-server.c
copy to tools/blktap3/drivers/tapdisk-server.c
--- a/tools/blktap2/drivers/tapdisk-server.c
+++ b/tools/blktap3/drivers/tapdisk-server.c
@@ -25,6 +25,7 @@
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
+
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
@@ -32,18 +33,32 @@
 #include <sys/ioctl.h>
 #include <sys/signal.h>
 
-#include "tapdisk-utils.h"
+#include "tapdisk-syslog.h"
 #include "tapdisk-server.h"
 #include "tapdisk-driver.h"
 #include "tapdisk-interface.h"
+#include "tapdisk-log.h"
 
 #define DBG(_level, _f, _a...)       tlog_write(_level, _f, ##_a)
 #define ERR(_err, _f, _a...)         tlog_error(_err, _f, ##_a)
 
- tapdisk_server_t server;
+#define TAPDISK_TIOCBS              (TAPDISK_DATA_REQUESTS + 50)
+
+typedef struct tapdisk_server {
+    int run;
+
+    struct tqh_td_vbd_handle vbds;
+    scheduler_t scheduler;
+    struct tqueue aio_queue;
+    char *name;
+    char *ident;
+    int facility;
+} tapdisk_server_t;
+
+static tapdisk_server_t server;
 
 #define tapdisk_server_for_each_vbd(vbd, tmp)                          \
-       list_for_each_entry_safe(vbd, tmp, &server.vbds, next)
+       TAILQ_FOREACH_SAFE(vbd, &server.vbds, entry, tmp)
 
 td_image_t *
 tapdisk_server_get_shared_image(td_image_t *image)
@@ -56,26 +71,26 @@ tapdisk_server_get_shared_image(td_image
 
        tapdisk_server_for_each_vbd(vbd, tmpv)
                tapdisk_vbd_for_each_image(vbd, img, tmpi)
-                       if (img->type == image->type &&
-                           !strcmp(img->name, image->name))
+        if (img->type == image->type && !strcmp(img->name, image->name))
                                return img;
 
        return NULL;
 }
 
-struct list_head *
-tapdisk_server_get_all_vbds(void)
+struct tqh_td_vbd_handle *tapdisk_server_get_all_vbds(void)
 {
        return &server.vbds;
 }
 
 td_vbd_t *
-tapdisk_server_get_vbd(uint16_t uuid)
+tapdisk_server_get_vbd(const char *params)
 {
        td_vbd_t *vbd, *tmp;
 
+    assert(params);
+
        tapdisk_server_for_each_vbd(vbd, tmp)
-               if (vbd->uuid == uuid)
+               if (!strcmp(vbd->name, params))
                        return vbd;
 
        return NULL;
@@ -84,14 +99,13 @@ tapdisk_server_get_vbd(uint16_t uuid)
 void
 tapdisk_server_add_vbd(td_vbd_t *vbd)
 {
-       list_add_tail(&vbd->next, &server.vbds);
+    TAILQ_INSERT_TAIL(&server.vbds, vbd, entry);
 }
 
 void
 tapdisk_server_remove_vbd(td_vbd_t *vbd)
 {
-       list_del(&vbd->next);
-       INIT_LIST_HEAD(&vbd->next);
+    TAILQ_REMOVE(&server.vbds, vbd, entry);
        tapdisk_server_check_state();
 }
 
@@ -111,13 +125,14 @@ tapdisk_server_debug(void)
        tapdisk_server_for_each_vbd(vbd, tmp)
                tapdisk_vbd_debug(vbd);
 
-       tlog_flush();
+    DBG(TLOG_INFO, "debug log completed\n");
+    tlog_precious();
 }
 
 void
 tapdisk_server_check_state(void)
 {
-       if (list_empty(&server.vbds))
+    if (TAILQ_EMPTY(&server.vbds))
                server.run = 0;
 }
 
@@ -136,7 +151,12 @@ tapdisk_server_unregister_event(event_id
 }
 
 void
-tapdisk_server_set_max_timeout(int seconds)
+tapdisk_server_mask_event(event_id_t event, int masked)
+{
+    return scheduler_mask_event(&server.scheduler, event, masked);
+}
+
+void tapdisk_server_set_max_timeout(int seconds)
 {
        scheduler_set_max_timeout(&server.scheduler, seconds);
 }
@@ -180,7 +200,6 @@ tapdisk_server_submit_tiocbs(void)
 static void
 tapdisk_server_kick_responses(void)
 {
-       int n;
        td_vbd_t *vbd, *tmp;
 
        tapdisk_server_for_each_vbd(vbd, tmp)
@@ -196,8 +215,19 @@ tapdisk_server_check_vbds(void)
                tapdisk_vbd_check_state(vbd);
 }
 
-static void
-tapdisk_server_stop_vbds(void)
+static int
+tapdisk_server_recheck_vbds(void)
+{
+    td_vbd_t *vbd, *tmp;
+    int rv = 0;
+
+    tapdisk_server_for_each_vbd(vbd, tmp)
+        rv += tapdisk_vbd_recheck_state(vbd);
+
+    return rv;
+}
+
+static void tapdisk_server_stop_vbds(void)
 {
        td_vbd_t *vbd, *tmp;
 
@@ -218,9 +248,49 @@ tapdisk_server_close_aio(void)
        tapdisk_free_queue(&server.aio_queue);
 }
 
-static void
-tapdisk_server_close(void)
+int tapdisk_server_openlog(const char *name, int options, int facility)
 {
+    server.facility = facility;
+    server.name = strdup(name);
+    server.ident = tapdisk_syslog_ident(name);
+
+    if (!server.name || !server.ident)
+        return -errno;
+
+    openlog(server.ident, options, facility);
+
+    return 0;
+}
+
+void tapdisk_server_closelog(void)
+{
+    closelog();
+
+    free(server.name);
+    server.name = NULL;
+
+    free(server.ident);
+    server.ident = NULL;
+}
+
+static int tapdisk_server_open_tlog(void)
+{
+    int err = 0;
+
+    if (server.name)
+        err = tlog_open(server.name, server.facility, TLOG_WARN);
+
+    return err;
+}
+
+static void tapdisk_server_close_tlog(void)
+{
+    tlog_close();
+}
+
+static void tapdisk_server_close(void)
+{
+    tapdisk_server_close_tlog();
        tapdisk_server_close_aio();
 }
 
@@ -238,8 +308,12 @@ tapdisk_server_iterate(void)
                DBG(TLOG_WARN, "server wait returned %d\n", ret);
 
        tapdisk_server_check_vbds();
-       tapdisk_server_submit_tiocbs();
-       tapdisk_server_kick_responses();
+    do {
+        tapdisk_server_submit_tiocbs();
+        tapdisk_server_kick_responses();
+
+        ret = tapdisk_server_recheck_vbds();
+    } while (ret);
 }
 
 static void
@@ -272,6 +346,7 @@ tapdisk_server_signal_handler(int signal
                break;
 
        case SIGUSR1:
+        DBG(TLOG_INFO, "debugging on signal %d\n", signal);
                tapdisk_server_debug();
                break;
        }
@@ -281,7 +356,7 @@ int
 tapdisk_server_init(void)
 {
        memset(&server, 0, sizeof(server));
-       INIT_LIST_HEAD(&server.vbds);
+    TAILQ_INIT(&server.vbds);
 
        scheduler_initialize(&server.scheduler);
 
@@ -297,17 +372,23 @@ tapdisk_server_complete(void)
        if (err)
                goto fail;
 
+    err = tapdisk_server_open_tlog();
+    if (err)
+        goto fail;
+
        server.run = 1;
 
        return 0;
 
 fail:
+    tapdisk_server_close_tlog();
        tapdisk_server_close_aio();
        return err;
 }
 
 int
-tapdisk_server_initialize(void)
+tapdisk_server_initialize(const char *read __attribute__((unused)),
+        const char *write __attribute__((unused)))
 {
        int err;
 

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