File blktap-error-handling.patch of Package xen
Index: xen-3.3.1-testing/tools/blktap/drivers/blktapctrl.c
===================================================================
--- xen-3.3.1-testing.orig/tools/blktap/drivers/blktapctrl.c
+++ xen-3.3.1-testing/tools/blktap/drivers/blktapctrl.c
@@ -662,9 +662,6 @@ static int blktapctrl_new_blkif(blkif_t
DPRINTF("Received a poll for a new vbd\n");
if ( ((blk=blkif->info) != NULL) && (blk->params != NULL) ) {
- if (blktap_interface_create(ctlfd, &major, &minor, blkif) < 0)
- return -1;
-
if (test_path(blk->params, &ptr, &type, &exist, &use_ioemu) != 0) {
DPRINTF("Error in blktap device string(%s).\n",
blk->params);
@@ -693,10 +690,6 @@ static int blktapctrl_new_blkif(blkif_t
blkif->fds[WRITE] = exist->fds[WRITE];
}
- add_disktype(blkif, type);
- blkif->major = major;
- blkif->minor = minor;
-
image = (image_t *)malloc(sizeof(image_t));
blkif->prv = (void *)image;
blkif->ops = &tapdisk_ops;
@@ -720,11 +713,18 @@ static int blktapctrl_new_blkif(blkif_t
goto fail;
}
+ if (blktap_interface_create(ctlfd, &major, &minor, blkif) < 0)
+ return -1;
+
+ blkif->major = major;
+ blkif->minor = minor;
+
+ add_disktype(blkif, type);
+
} else return -1;
return 0;
fail:
- ioctl(ctlfd, BLKTAP_IOCTL_FREEINTF, minor);
return -EINVAL;
}
Index: xen-3.3.1-testing/tools/blktap/lib/xenbus.c
===================================================================
--- xen-3.3.1-testing.orig/tools/blktap/lib/xenbus.c
+++ xen-3.3.1-testing/tools/blktap/lib/xenbus.c
@@ -48,6 +48,7 @@
#include <poll.h>
#include <time.h>
#include <sys/time.h>
+#include <unistd.h>
#include "blktaplib.h"
#include "list.h"
#include "xs_api.h"
@@ -149,6 +150,130 @@ static int backend_remove(struct xs_hand
return 0;
}
+static int check_sharing(struct xs_handle *h, struct backend_info *be)
+{
+ char *dom_uuid;
+ char *cur_dom_uuid;
+ char *path;
+ char *mode;
+ char *params;
+ char **domains;
+ char **devices;
+ int i, j;
+ unsigned int num_dom, num_dev;
+ blkif_info_t *info;
+ int ret = 0;
+
+ /* If the mode contains '!' or doesn't contain 'w' don't check anything */
+ xs_gather(h, be->backpath, "mode", NULL, &mode, NULL);
+ if (strchr(mode, '!'))
+ goto out;
+ if (strchr(mode, 'w') == NULL)
+ goto out;
+
+ /* Get the UUID of the domain we want to attach to */
+ if (asprintf(&path, "/local/domain/%ld", be->frontend_id) == -1)
+ goto fail;
+ xs_gather(h, path, "vm", NULL, &dom_uuid, NULL);
+ free(path);
+
+ /* Iterate through the devices of all VMs */
+ domains = xs_directory(h, XBT_NULL, "backend/tap", &num_dom);
+ if (domains == NULL)
+ num_dom = 0;
+
+ for (i = 0; !ret && (i < num_dom); i++) {
+
+ /* If it's the same VM, no action needed */
+ if (asprintf(&path, "/local/domain/%s", domains[i]) == -1) {
+ ret = -1;
+ break;
+ }
+ xs_gather(h, path, "vm", NULL, &cur_dom_uuid, NULL);
+ free(path);
+
+ if (!strcmp(cur_dom_uuid, dom_uuid)) {
+ free(cur_dom_uuid);
+ continue;
+ }
+
+ /* Check the devices */
+ if (asprintf(&path, "backend/tap/%s", domains[i]) == -1) {
+ ret = -1;
+ free(cur_dom_uuid);
+ break;
+ }
+ devices = xs_directory(h, XBT_NULL, path, &num_dev);
+ if (devices == NULL)
+ num_dev = 0;
+ free(path);
+
+ for (j = 0; !ret && (j < num_dev); j++) {
+ if (asprintf(&path, "backend/tap/%s/%s", domains[i], devices[j]) == -1) {
+ ret = -1;
+ break;
+ }
+ xs_gather(h, path, "params", NULL, ¶ms, NULL);
+ free(path);
+
+ info = be->blkif->info;
+ if (strcmp(params, info->params)) {
+ ret = -1;
+ }
+
+ free(params);
+ }
+
+ free(cur_dom_uuid);
+ free(devices);
+ }
+ free(domains);
+ free(dom_uuid);
+ goto out;
+
+fail:
+ ret = -1;
+out:
+ free(mode);
+ return ret;
+}
+
+static int check_image(struct xs_handle *h, struct backend_info *be,
+ const char** errmsg)
+{
+ const char *path;
+ int mode;
+ blkif_t *blkif = be->blkif;
+ blkif_info_t *info = blkif->info;
+
+ /* Strip off the image type */
+ path = strchr(info->params, ':');
+ if (path == NULL)
+ path = info->params;
+ else
+ path++;
+
+ /* Check if the image exists and access is permitted */
+ mode = R_OK;
+ if (!be->readonly)
+ mode |= W_OK;
+ if (access(path, mode)) {
+ if (errno == ENOENT)
+ *errmsg = "File not found.";
+ else
+ *errmsg = "Insufficient file permissions.";
+ return -1;
+ }
+
+ /* Check that the image is not attached to a different VM */
+ if (check_sharing(h, be)) {
+ *errmsg = "File already in use by other domain";
+ return -1;
+ }
+
+ return 0;
+}
+
static void ueblktap_setup(struct xs_handle *h, char *bepath)
{
struct backend_info *be;
@@ -156,6 +281,7 @@ static void ueblktap_setup(struct xs_han
int len, er, deverr;
long int pdev = 0, handle;
blkif_info_t *blk;
+ const char* errmsg = NULL;
be = be_lookup_be(bepath);
if (be == NULL)
@@ -211,6 +337,9 @@ static void ueblktap_setup(struct xs_han
be->pdev = pdev;
}
+ if (check_image(h, be, &errmsg))
+ goto fail;
+
er = blkif_init(be->blkif, handle, be->pdev, be->readonly);
if (er != 0) {
DPRINTF("Unable to open device %s\n",blk->params);
@@ -246,12 +375,21 @@ static void ueblktap_setup(struct xs_han
}
be->blkif->state = CONNECTED;
+ xs_printf(h, be->backpath, "hotplug-status", "connected");
+
DPRINTF("[SETUP] Complete\n\n");
goto close;
fail:
- if ( (be != NULL) && (be->blkif != NULL) )
+ if (be) {
+ if (errmsg == NULL)
+ errmsg = "Setting up the backend failed. See the log "
+ "files in /var/log/xen/ for details.";
+ xs_printf(h, be->backpath, "hotplug-error", errmsg);
+ xs_printf(h, be->backpath, "hotplug-status", "error");
+
backend_remove(h, be);
+ }
close:
if (path)
free(path);
@@ -286,7 +424,8 @@ static void ueblktap_probe(struct xs_han
len = strsep_len(bepath, '/', 7);
if (len < 0)
goto free_be;
- bepath[len] = '\0';
+ if (bepath[len] != '\0')
+ goto free_be;
be = malloc(sizeof(*be));
if (!be) {
Index: xen-3.3.1-testing/tools/examples/xen-backend.rules
===================================================================
--- xen-3.3.1-testing.orig/tools/examples/xen-backend.rules
+++ xen-3.3.1-testing/tools/examples/xen-backend.rules
@@ -1,4 +1,3 @@
-SUBSYSTEM=="xen-backend", KERNEL=="tap*", RUN+="/etc/xen/scripts/blktap $env{ACTION}"
SUBSYSTEM=="xen-backend", KERNEL=="vbd*", RUN+="/etc/xen/scripts/block $env{ACTION}"
SUBSYSTEM=="xen-backend", KERNEL=="vtpm*", RUN+="/etc/xen/scripts/vtpm $env{ACTION}"
SUBSYSTEM=="xen-backend", KERNEL=="vif*", ACTION=="online", RUN+="$env{script} online"
