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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] RFC: libxl: Change hotplug script interface to use physical-device-path
* Change block-common.sh on Linux to write physical-device-path with
the path of the device node, rather than physical-device with its
major:minor numbers.
* Have the libxl Linux hotplug script scheduler convert this, by
reading physical-device-path and writing physical-device. This
happens just when we have decided that there is no more script to
run.
* When libxl itself writes the device to xenstore, have it write
physical-device-path. On Linux this will be converted to
physical-device by the new code discussed above.
* Add a note about libxl__device_physdisk_major_minor's poor error
handling.
* Add an xxx about the fact that the sharing check in
tools/hotplug/Linux/block needs adjusting. Note that WITHOUT THIS
OTHER FIX THE CHANGE TO BLOCK-COMMON.SH IS BROKEN. This is one
reason this patch is RFC.
* Untested. That is the other reason this patch is RFC.
(I have checked that it does compile.)
I wasn't able to find a document describing the hotplug script
interface (!) so this patch does not contain docs hunks.
CC: George Dunlap <george.dunlap@xxxxxxxxxx>
CC: Roger Pau Monne <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
---
tools/hotplug/Linux/block-common.sh | 19 +++-------
tools/libxl/libxl.c | 5 +--
tools/libxl/libxl_internal.h | 1 +
tools/libxl/libxl_linux.c | 70 ++++++++++++++++++++++++++++++++++-
4 files changed, 75 insertions(+), 20 deletions(-)
diff --git a/tools/hotplug/Linux/block-common.sh
b/tools/hotplug/Linux/block-common.sh
index ee95009..560f189 100644
--- a/tools/hotplug/Linux/block-common.sh
+++ b/tools/hotplug/Linux/block-common.sh
@@ -50,23 +50,14 @@ device_major_minor()
##
-# Write physical-device = MM,mm to the store, where MM and mm are the major
-# and minor numbers of device respectively.
+# Write physical-device-path = "$1"
#
-# @param device The device from which major and minor numbers are read, which
-# will be written into the store.
+# @param device The device which will be written into the store.
#
write_dev() {
- local mm
-
- mm=$(device_major_minor "$1")
-
- if [ -z $mm ]
- then
- fatal "Backend device does not exist"
- fi
-
- xenstore_write "$XENBUS_PATH/physical-device" "$mm"
+ xxx check_sharing in block needs fixing too
+
+ xenstore_write "$XENBUS_PATH/physical-device-path" "$1"
success
}
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 4cdc169..0bcfada 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2450,10 +2450,7 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
*/
if (!disk->script &&
disk->backend_domid == LIBXL_TOOLSTACK_DOMID) {
- int major, minor;
- if (!libxl__device_physdisk_major_minor(dev, &major,
&minor))
- flexarray_append_pair(back, "physical-device",
- GCSPRINTF("%x:%x", major,
minor));
+ flexarray_append_pair(back, "physical-device-path", dev);
}
assert(device->backend_kind == LIBXL__DEVICE_KIND_VBD);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 005fe53..ada5f40 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1154,6 +1154,7 @@ _hidden char
*libxl__device_disk_string_of_format(libxl_disk_format format);
_hidden int libxl__device_disk_set_backend(libxl__gc*, libxl_device_disk*);
_hidden int libxl__device_physdisk_major_minor(const char *physpath, int
*major, int *minor);
+ /* xxx libxl__device_physdisk_major_minor has irregular error handling */
_hidden int libxl__device_disk_dev_number(const char *virtpath,
int *pdisk, int *ppartition);
diff --git a/tools/libxl/libxl_linux.c b/tools/libxl/libxl_linux.c
index be4afc6..aa7b42d 100644
--- a/tools/libxl/libxl_linux.c
+++ b/tools/libxl/libxl_linux.c
@@ -233,6 +233,65 @@ error:
return rc;
}
+static int disk_copy_block_device(libxl__gc *gc, libxl__device *dev,
+ libxl__device_action action)
+{
+ int rc;
+ xs_transaction_t t = 0;
+ const char *be_path = libxl__device_frontend_path(gc, dev);
+ const char *majmin_path = GCSPRINTF("%s/physical-device", be_path);
+ const char *path_path = GCSPRINTF("%s/physical-device-path", be_path);
+ int major, minor;
+
+ if (action != LIBXL__DEVICE_ACTION_ADD)
+ return 0;
+
+ for (;;) {
+ rc = libxl__xs_transaction_start(gc, &t);
+ if (rc) goto out;
+
+ const char *majmin;
+ rc = libxl__xs_read_checked(gc,t, majmin_path, &majmin);
+ if (rc) goto out;
+ if (majmin) {
+ /* Old-style Linux-only hotplug script wrote physical-device */
+ rc = 0;
+ goto out;
+ }
+
+ const char *bdev;
+ rc = libxl__xs_read_checked(gc,t, path_path, &bdev);
+ if (rc) goto out;
+ if (!bdev) {
+ LOGE(ERROR, "nothing wrote physical device to %s", path_path);
+ rc = ERROR_FAIL;
+ goto out;
+ }
+
+ if (!libxl__device_physdisk_major_minor(bdev, &major, &minor)) {
+ LOG(ERROR, "libxl__device_physdisk_major_minor failed (on %s)",
+ bdev);
+ rc = ERROR_FAIL;
+ goto out;
+ }
+
+ majmin = GCSPRINTF("%x:%x", major, minor);
+ rc = libxl__xs_write_checked(gc,t, majmin_path, majmin);
+ if (rc) goto out;
+
+ rc = libxl__xs_transaction_commit(gc, &t);
+ if (!rc) break;
+ if (rc<0) goto out;
+ }
+
+ return rc;
+
+ out:
+ libxl__xs_transaction_abort(gc, &t);
+ return rc;
+}
+
+
int libxl__get_hotplug_script_info(libxl__gc *gc, libxl__device *dev,
char ***args, char ***env,
libxl__device_action action,
@@ -245,9 +304,16 @@ int libxl__get_hotplug_script_info(libxl__gc *gc,
libxl__device *dev,
if (num_exec != 0) {
LOG(DEBUG, "num_exec %d, not running hotplug scripts", num_exec);
rc = 0;
- goto out;
+ } else {
+ rc = libxl__hotplug_disk(gc, dev, args, env, action);
+ }
+ if (!rc) {
+ /* No more hotplug scripts to run. But, the hotplug
+ * scripts write physical-device-path but we blkback wants
+ * physical-device (major:minor). So now we adjust
+ * that. */
+ rc = disk_copy_block_device(gc, dev, action);
}
- rc = libxl__hotplug_disk(gc, dev, args, env, action);
break;
case LIBXL__DEVICE_KIND_VIF:
/*
--
1.7.10.4
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