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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH RFC v2 2/3] libxl: Port libxl_blktap2.c to blktap2.5 API.
This is code is in preparation for building against an external blktap
tree.
tap_ctl_find() has gone away, so in some cases we use
tap_ctl_find_minor(), and in other cases we use a
locally-reimplemented version of tap_ctl_find().
tap_ctl_create() has an extra three parameters, including a flags
parameter which can be used to designate a disk image as read-only.
Pass the readwrite disk flag here so we can now open backends on
read-only storage.
tap_ctl_destroy() now has two extra arguments as well; add sensible
default values.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
---
CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
CC: Ian Jackson <ian.jackson@xxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Dave Scott <Dave.Scott@xxxxxxxxxxxxx>
CC: Jonathan Ludlam <Jonathan.Ludlam@xxxxxxxxxxxxx>
CC: Wen Congyang <wency@xxxxxxxxxxxxxx>
CC: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
---
tools/libxl/libxl.c | 6 +++--
tools/libxl/libxl_blktap2.c | 58 ++++++++++++++++++++++++++++++++++++--------
tools/libxl/libxl_dm.c | 3 ++-
tools/libxl/libxl_internal.h | 3 ++-
4 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index debb20c..54a9fb7 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2484,7 +2484,8 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
case LIBXL_DISK_BACKEND_TAP:
if (dev == NULL) {
dev = libxl__blktap_devpath(gc, disk->pdev_path,
- disk->format);
+ disk->format,
+ disk->readwrite);
if (!dev) {
LOG(ERROR, "failed to get blktap devpath for %p\n",
disk->pdev_path);
@@ -3078,7 +3079,8 @@ void libxl__device_disk_local_initiate_attach(libxl__egc
*egc,
break;
case LIBXL_DISK_FORMAT_VHD:
dev = libxl__blktap_devpath(gc, disk->pdev_path,
- disk->format);
+ disk->format,
+ disk->readwrite);
break;
case LIBXL_DISK_FORMAT_QCOW:
case LIBXL_DISK_FORMAT_QCOW2:
diff --git a/tools/libxl/libxl_blktap2.c b/tools/libxl/libxl_blktap2.c
index 2053403..24939d7 100644
--- a/tools/libxl/libxl_blktap2.c
+++ b/tools/libxl/libxl_blktap2.c
@@ -23,26 +23,62 @@ int libxl__blktap_enabled(libxl__gc *gc)
return !tap_ctl_check(&msg);
}
+static int tap_ctl_find(const char *type, const char *disk, tap_list_t *tap)
+{
+ int err;
+ struct list_head list = LIST_HEAD_INIT(list);
+ tap_list_t *entry;
+
+ err = tap_ctl_list(&list);
+ if (err)
+ return err;
+
+ err = ERROR_FAIL;
+
+ tap_list_for_each_entry(entry, &list) {
+ if (type && (!entry->type || strcmp(entry->type, type)))
+ continue;
+
+ if (disk && (!entry->path || strcmp(entry->path, disk)))
+ continue;
+
+ tap->minor = entry->minor;
+ tap->pid = entry->pid;
+ err = 0;
+ break;
+ }
+ tap_ctl_list_free(&list);
+
+ return err;
+}
+
char *libxl__blktap_devpath(libxl__gc *gc,
const char *disk,
- libxl_disk_format format)
+ libxl_disk_format format,
+ int readwrite)
{
const char *type;
char *params, *devname = NULL;
- tap_list_t tap;
int err;
+ int minor;
+ int flags;
type = libxl__device_disk_string_of_format(format);
- err = tap_ctl_find(type, disk, &tap);
- if (err == 0) {
- devname = libxl__sprintf(gc, "/dev/xen/blktap-2/tapdev%d", tap.minor);
+
+ minor = tap_ctl_find_minor(type, disk);
+ if (minor >= 0) {
+ devname = libxl__sprintf(gc, "/dev/xen/blktap-2/tapdev%d", minor);
if (devname)
return devname;
}
params = libxl__sprintf(gc, "%s:%s", type, disk);
- err = tap_ctl_create(params, &devname);
+ fprintf(stderr, "DEBUG %s %d %s\n", __func__, __LINE__, params);
+ flags = readwrite ? 0 : TAPDISK_MESSAGE_FLAG_RDONLY;
+
+ err = tap_ctl_create(params, &devname, flags, -1, 0, 0);
if (!err) {
+ fprintf(stderr, "DEBUG %s %d %s\n", __func__, __LINE__, devname);
libxl__ptr_add(gc, devname);
return devname;
}
@@ -55,7 +91,8 @@ int libxl__device_destroy_tapdisk(libxl__gc *gc, const char
*params)
{
char *type, *disk;
int err;
- tap_list_t tap;
+ struct list_head list = LIST_HEAD_INIT(list);
+ tap_list_t tap = { .minor=-1, .pid=-1 };
type = libxl__strdup(gc, params);
@@ -65,19 +102,20 @@ int libxl__device_destroy_tapdisk(libxl__gc *gc, const
char *params)
return ERROR_INVAL;
}
+ fprintf(stderr, "DEBUG %s %d type=%s
disk=%s\n",__func__,__LINE__,type,disk);
*disk++ = '\0';
err = tap_ctl_find(type, disk, &tap);
- if (err < 0) {
+ if (err) {
/* returns -errno */
LOGEV(ERROR, -err, "Unable to find type %s disk %s", type, disk);
return ERROR_FAIL;
}
- err = tap_ctl_destroy(tap.id, tap.minor);
+ err = tap_ctl_destroy(tap.pid, tap.minor, 1, NULL);
if (err < 0) {
LOGEV(ERROR, -err, "Failed to destroy tap device id %d minor %d",
- tap.id, tap.minor);
+ tap.pid, tap.minor);
return ERROR_FAIL;
}
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 30c1578..d13ef9e 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -835,7 +835,8 @@ static char ** libxl__build_device_model_args_new(libxl__gc
*gc,
if (disks[i].backend == LIBXL_DISK_BACKEND_TAP) {
format = qemu_disk_format_string(LIBXL_DISK_FORMAT_RAW);
pdev_path = libxl__blktap_devpath(gc, disks[i].pdev_path,
- disks[i].format);
+ disks[i].format,
+ disks[i].readwrite);
} else {
pdev_path = disks[i].pdev_path;
}
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 10d1252..46968f1 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1574,7 +1574,8 @@ _hidden int libxl__blktap_enabled(libxl__gc *gc);
*/
_hidden char *libxl__blktap_devpath(libxl__gc *gc,
const char *disk,
- libxl_disk_format format);
+ libxl_disk_format format,
+ int readwrite);
/* libxl__device_destroy_tapdisk:
* Destroys any tapdisk process associated with the backend represented
--
1.9.1
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