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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v2 1/2] libxl: provide a mechanism to define a device 'safe remove' function...
From: Paul Durrant <pdurrant@xxxxxxxxxx>
... and use it to define libxl_device_disk_safe_remove().
This patch builds on the existent macro magic by using a new value of the
'force' field in in libxl__ao_device.
It is currently defined as an int but is used in a boolean manner where
1 means the operation is forced and 0 means it is not (but is actually forced
after a 10s time-out). In adding a third value, this patch re-defines 'force'
as a struct type (libxl__force) with a single 'flag' field taking an
enumerated value:
LIBXL__FORCE_AUTO - corresponding to the old 0 value
LIBXL__FORCE_ON - corresponding to the old 1 value
LIBXL__FORCE_OFF - the new value
The LIBXL_DEFINE_DEVICE_REMOVE() macro is then modified to define the
libxl_device_<type>_remove() and libxl_device_<type>_destroy() functions,
setting LIBXL__FORCE_AUTO and LIBXL__FORCE_ON (respectively) in the
libxl__ao_device passed to libxl__initiate_device_generic_remove() and a
new macro, LIBXL_DEFINE_DEVICE_SAFE_REMOVE(), is defined that sets
LIBXL__FORCE_OFF instead. This macro is used to define the new
libxl_device_disk_safe_remove() function.
Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
---
Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
v2:
- New in v2
---
tools/libxl/libxl.h | 33 +++++++++++++++++++++++++--------
tools/libxl/libxl_device.c | 9 +++++----
tools/libxl/libxl_disk.c | 4 +++-
tools/libxl/libxl_domain.c | 2 +-
tools/libxl/libxl_internal.h | 30 +++++++++++++++++++++++-------
5 files changed, 57 insertions(+), 21 deletions(-)
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 1cd6c38e83..1ea5b4f446 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -438,6 +438,12 @@
*/
#define LIBXL_HAVE_CREATEINFO_PASSTHROUGH 1
+/*
+ * LIBXL_HAVE_DISK_SAFE_REMOVE indicates that the
+ * libxl_device_disk_safe_remove() function is defined.
+ */
+#define LIBXL_HAVE_DISK_SAFE_REMOVE 1
+
/*
* libxl ABI compatibility
*
@@ -1936,6 +1942,15 @@ void libxl_vcpuinfo_list_free(libxl_vcpuinfo *, int
nr_vcpus);
* structure is passed in are filled in with appropriate values for
* the device created.
*
+ * libxl_device_<type>_destroy(ctx, domid, device):
+ *
+ * Removes the given device from the specified domain without guest
+ * co-operation. It is guest specific what affect this will have on
+ * a running guest.
+ *
+ * This function does not interact with the guest and therefore
+ * cannot block on the guest.
+ *
* libxl_device_<type>_remove(ctx, domid, device):
*
* Removes the given device from the specified domain by performing
@@ -1943,16 +1958,14 @@ void libxl_vcpuinfo_list_free(libxl_vcpuinfo *, int
nr_vcpus);
* guest is running.
*
* This method is currently synchronous and therefore can block
- * while interacting with the guest.
- *
- * libxl_device_<type>_destroy(ctx, domid, device):
+ * while interacting with the guest. There is a time-out of 10s on
+ * this interaction after which libxl_device_<type>_destroy()
+ * semantics apply.
*
- * Removes the given device from the specified domain without guest
- * co-operation. It is guest specific what affect this will have on
- * a running guest.
+ * libxl_device_<type>_safe_remove(ctx, domid, device):
*
- * This function does not interact with the guest and therefore
- * cannot block on the guest.
+ * This has the same semantics as libxl_device_<type>_remove() but,
+ * in the event of hitting the 10s time-out, this function will fail.
*
* Controllers
* -----------
@@ -2033,6 +2046,10 @@ int libxl_device_disk_destroy(libxl_ctx *ctx, uint32_t
domid,
libxl_device_disk *disk,
const libxl_asyncop_how *ao_how)
LIBXL_EXTERNAL_CALLERS_ONLY;
+int libxl_device_disk_safe_remove(libxl_ctx *ctx, uint32_t domid,
+ libxl_device_disk *disk,
+ const libxl_asyncop_how *ao_how)
+ LIBXL_EXTERNAL_CALLERS_ONLY;
libxl_device_disk *libxl_device_disk_list(libxl_ctx *ctx,
uint32_t domid, int *num)
diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 0381c5d509..e081faf9a9 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -973,7 +973,7 @@ void libxl__initiate_device_generic_remove(libxl__egc *egc,
goto out;
}
- if (aodev->force)
+ if (aodev->force.flag == LIBXL__FORCE_ON)
libxl__xs_path_cleanup(gc, t,
libxl__device_frontend_path(gc,
aodev->dev));
@@ -1092,9 +1092,9 @@ static void device_backend_callback(libxl__egc *egc,
libxl__ev_devstate *ds,
if (rc == ERROR_TIMEDOUT &&
aodev->action == LIBXL__DEVICE_ACTION_REMOVE &&
- !aodev->force) {
+ aodev->force.flag == LIBXL__FORCE_AUTO) {
LOGD(DEBUG, aodev->dev->domid, "Timeout reached, initiating forced
remove");
- aodev->force = 1;
+ aodev->force.flag = LIBXL__FORCE_ON;
libxl__initiate_device_generic_remove(egc, aodev);
return;
}
@@ -1319,7 +1319,8 @@ static void device_hotplug_done(libxl__egc *egc,
libxl__ao_device *aodev)
device_hotplug_clean(gc, aodev);
/* Clean xenstore if it's a disconnection */
- if (aodev->action == LIBXL__DEVICE_ACTION_REMOVE) {
+ if (aodev->action == LIBXL__DEVICE_ACTION_REMOVE &&
+ (aodev->force.flag == LIBXL__FORCE_ON || !aodev->rc)) {
rc = libxl__device_destroy(gc, aodev->dev);
if (!aodev->rc)
aodev->rc = rc;
diff --git a/tools/libxl/libxl_disk.c b/tools/libxl/libxl_disk.c
index ddc1eec176..de183e0fb0 100644
--- a/tools/libxl/libxl_disk.c
+++ b/tools/libxl/libxl_disk.c
@@ -1277,7 +1277,7 @@ void libxl__device_disk_local_initiate_detach(libxl__egc
*egc,
aodev->action = LIBXL__DEVICE_ACTION_REMOVE;
aodev->dev = device;
aodev->callback = local_device_detach_cb;
- aodev->force = 0;
+ aodev->force.flag = LIBXL__FORCE_AUTO;
libxl__initiate_device_generic_remove(egc, aodev);
return;
}
@@ -1318,10 +1318,12 @@ out:
* libxl__add_disks
* libxl_device_disk_remove
* libxl_device_disk_destroy
+ * libxl_device_disk_safe_remove
*/
LIBXL_DEFINE_DEVICE_ADD(disk)
LIBXL_DEFINE_DEVICES_ADD(disk)
LIBXL_DEFINE_DEVICE_REMOVE(disk)
+LIBXL_DEFINE_DEVICE_SAFE_REMOVE(disk)
static int libxl_device_disk_compare(const libxl_device_disk *d1,
const libxl_device_disk *d2)
diff --git a/tools/libxl/libxl_domain.c b/tools/libxl/libxl_domain.c
index 39f08a6519..5d4ec90711 100644
--- a/tools/libxl/libxl_domain.c
+++ b/tools/libxl/libxl_domain.c
@@ -1279,7 +1279,7 @@ static void dm_destroy_cb(libxl__egc *egc,
dis->drs.ao = ao;
dis->drs.domid = domid;
dis->drs.callback = devices_destroy_cb;
- dis->drs.force = 1;
+ dis->drs.force.flag = LIBXL__FORCE_ON;
libxl__devices_destroy(egc, &dis->drs);
}
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index e16ae9630b..1fcf85c3e2 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2730,12 +2730,20 @@ _hidden void libxl__prepare_ao_device(libxl__ao *ao,
libxl__ao_device *aodev);
/* generic callback for devices that only need to set ao_complete */
_hidden void device_addrm_aocomplete(libxl__egc *egc, libxl__ao_device *aodev);
+typedef struct {
+ enum {
+ LIBXL__FORCE_AUTO, /* Re-execute with FORCE_ON if op times out */
+ LIBXL__FORCE_ON,
+ LIBXL__FORCE_OFF,
+ } flag;
+} libxl__force;
+
struct libxl__ao_device {
/* filled in by user */
libxl__ao *ao;
libxl__device_action action;
libxl__device *dev;
- int force;
+ libxl__force force;
libxl__device_callback *callback;
/* return value, zeroed by user on entry, is valid on callback */
int rc;
@@ -3787,7 +3795,7 @@ _hidden void libxl__bootloader_run(libxl__egc*,
libxl__bootloader_state *st);
aodev->action = LIBXL__DEVICE_ACTION_REMOVE; \
aodev->dev = device; \
aodev->callback = device_addrm_aocomplete; \
- aodev->force = f; \
+ aodev->force.flag = f; \
libxl__initiate_device_##remtype##_remove(egc, aodev); \
\
out: \
@@ -3862,12 +3870,20 @@ _hidden void libxl__bootloader_run(libxl__egc*,
libxl__bootloader_state *st);
#define LIBXL_DEFINE_DEVICE_REMOVE(type) \
- LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, generic, remove, 0) \
- LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, generic, destroy, 1)
+ LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, generic, remove, \
+ LIBXL__FORCE_AUTO) \
+ LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, generic, destroy, \
+ LIBXL__FORCE_ON)
#define LIBXL_DEFINE_DEVICE_REMOVE_CUSTOM(type) \
- LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, type, remove, 0) \
- LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, type, destroy, 1)
+ LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, type, remove, \
+ LIBXL__FORCE_AUTO) \
+ LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, type, destroy, \
+ LIBXL__FORCE_ON)
+
+#define LIBXL_DEFINE_DEVICE_SAFE_REMOVE(type) \
+ LIBXL_DEFINE_DEVICE_REMOVE_EXT(type, generic, safe_remove, \
+ LIBXL__FORCE_OFF)
#define LIBXL_DEFINE_DEVICE_LIST(type) \
libxl_device_##type *libxl_device_##type##_list(libxl_ctx *ctx, \
@@ -4028,7 +4044,7 @@ struct libxl__devices_remove_state {
libxl__ao *ao;
uint32_t domid;
libxl__devices_remove_callback *callback;
- int force; /* libxl_device_TYPE_destroy rather than _remove */
+ libxl__force force; /* libxl_device_TYPE_destroy rather than _remove */
/* private */
libxl__multidev multidev;
int num_devices;
--
2.20.1
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