[lvm-devel] master - device: add infrastructure to support external device info
Peter Rajnoha
prajnoha at fedoraproject.org
Fri Jan 30 12:31:53 UTC 2015
Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=fbfde21e7cdc770f0a1189d40f983aa046d605bb
Commit: fbfde21e7cdc770f0a1189d40f983aa046d605bb
Parent: 578b236a19fab565a4416b17cbc26d53a72b66db
Author: Peter Rajnoha <prajnoha at redhat.com>
AuthorDate: Fri Dec 12 12:55:41 2014 +0100
Committer: Peter Rajnoha <prajnoha at redhat.com>
CommitterDate: Fri Jan 30 13:01:12 2015 +0100
device: add infrastructure to support external device info
---
lib/Makefile.in | 1 +
lib/device/dev-cache.c | 3 +
lib/device/dev-ext.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++
lib/device/device.h | 27 ++++++++
4 files changed, 195 insertions(+), 0 deletions(-)
diff --git a/lib/Makefile.in b/lib/Makefile.in
index bad5d8c..99cc0fe 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -56,6 +56,7 @@ SOURCES =\
datastruct/btree.c \
datastruct/str_list.c \
device/dev-cache.c \
+ device/dev-ext.c \
device/dev-io.c \
device/dev-md.c \
device/dev-swap.c \
diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index ba4ee54..7ad9fb8 100644
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -64,6 +64,9 @@ static void _dev_init(struct device *dev, int max_error_count)
dev->read_ahead = -1;
dev->max_error_count = max_error_count;
+ dev->ext.enabled = 0;
+ dev->ext.src = DEV_EXT_NONE;
+
dm_list_init(&dev->aliases);
dm_list_init(&dev->open_list);
}
diff --git a/lib/device/dev-ext.c b/lib/device/dev-ext.c
new file mode 100644
index 0000000..8f2024e
--- /dev/null
+++ b/lib/device/dev-ext.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2014 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "lib.h"
+#include "device.h"
+
+#ifdef UDEV_SYNC_SUPPORT
+#include <libudev.h>
+#endif
+
+struct ext_registry_item {
+ const char *name;
+ struct dev_ext *(* dev_ext_get) (struct device *dev);
+ int (*dev_ext_release) (struct device *dev);
+};
+
+#define EXT_REGISTER(id,name) [id] = { #name, &_dev_ext_get_ ## name, &_dev_ext_release_ ## name }
+
+/*
+ * DEV_EXT_NONE
+ */
+static struct dev_ext *_dev_ext_get_none(struct device *dev)
+{
+ dev->ext.handle = NULL;
+ return &dev->ext;
+}
+
+static int _dev_ext_release_none(struct device *dev)
+{
+ dev->ext.handle = NULL;
+ return 1;
+}
+
+/*
+ * DEV_EXT_UDEV
+ */
+static struct dev_ext *_dev_ext_get_udev(struct device *dev)
+{
+#ifdef UDEV_SYNC_SUPPORT
+ struct udev *udev;
+ struct udev_device *udev_device;
+
+ if (dev->ext.handle)
+ return &dev->ext;
+
+ if (!(udev = udev_get_library_context()))
+ return_NULL;
+
+ if (!(udev_device = udev_device_new_from_devnum(udev, 'b', dev->dev)))
+ return_NULL;
+
+ dev->ext.handle = (void *) udev_device;
+ return &dev->ext;
+#else
+ return NULL;
+#endif
+}
+
+static int _dev_ext_release_udev(struct device *dev)
+{
+#ifdef UDEV_SYNC_SUPPORT
+ if (!dev->ext.handle)
+ return 1;
+
+ /* udev_device_unref can't fail - it has no return value */
+ udev_device_unref((struct udev_device *) dev->ext.handle);
+ dev->ext.handle = NULL;
+ return 1;
+#else
+ return 0;
+#endif
+}
+
+static struct ext_registry_item _ext_registry[DEV_EXT_NUM] = {
+ EXT_REGISTER(DEV_EXT_NONE, none),
+ EXT_REGISTER(DEV_EXT_UDEV, udev)
+};
+
+const char *dev_ext_name(struct device *dev)
+{
+ return _ext_registry[dev->ext.src].name;
+}
+
+static const char *_ext_attached_msg = "External handle attached to device";
+
+struct dev_ext *dev_ext_get(struct device *dev)
+{
+ struct dev_ext *ext;
+ void *handle_ptr;
+
+ handle_ptr = dev->ext.handle;
+
+ if (!(ext = _ext_registry[dev->ext.src].dev_ext_get(dev)))
+ log_error("Failed to get external handle for device %s [%s].",
+ dev_name(dev), dev_ext_name(dev));
+ else if (handle_ptr != dev->ext.handle)
+ log_debug_devs("%s %s [%s:%p]", _ext_attached_msg, dev_name(dev),
+ dev_ext_name(dev), dev->ext.handle);
+
+ return ext;
+}
+
+int dev_ext_release(struct device *dev)
+{
+ int r;
+ void *handle_ptr;
+
+ if (!dev->ext.enabled ||
+ !dev->ext.handle)
+ return 1;
+
+ handle_ptr = dev->ext.handle;
+
+ if (!(r = _ext_registry[dev->ext.src].dev_ext_release(dev)))
+ log_error("Failed to release external handle for device %s [%s:%p].",
+ dev_name(dev), dev_ext_name(dev), dev->ext.handle);
+ else
+ log_debug_devs("External handle detached from device %s [%s:%p]",
+ dev_name(dev), dev_ext_name(dev), handle_ptr);
+
+ return r;
+}
+
+int dev_ext_enable(struct device *dev, dev_ext_t src)
+{
+ if (dev->ext.enabled && (dev->ext.src != src) && !dev_ext_release(dev)) {
+ log_error("Failed to enable external handle for device %s [%s].",
+ dev_name(dev), _ext_registry[src].name);
+ return 0;
+ }
+
+ dev->ext.src = src;
+ dev->ext.enabled = 1;
+
+ return 1;
+}
+
+int dev_ext_disable(struct device *dev)
+{
+ if (!dev->ext.enabled)
+ return 1;
+
+ if (!dev_ext_release(dev)) {
+ log_error("Failed to disable external handle for device %s [%s].",
+ dev_name(dev), dev_ext_name(dev));
+ return 0;
+ }
+
+ dev->ext.enabled = 0;
+ dev->ext.src = DEV_EXT_NONE;
+
+ return 1;
+}
diff --git a/lib/device/device.h b/lib/device/device.h
index c916a4b..0d38f96 100644
--- a/lib/device/device.h
+++ b/lib/device/device.h
@@ -29,6 +29,23 @@
#define DEV_O_DIRECT_TESTED 0x00000040 /* DEV_O_DIRECT is reliable */
/*
+ * Support for external device info.
+ * Any new external device info source needs to be
+ * registered using EXT_REGISTER macro in dev-ext.c.
+ */
+typedef enum {
+ DEV_EXT_NONE,
+ DEV_EXT_UDEV,
+ DEV_EXT_NUM
+} dev_ext_t;
+
+struct dev_ext {
+ int enabled;
+ dev_ext_t src;
+ void *handle;
+};
+
+/*
* All devices in LVM will be represented by one of these.
* pointer comparisons are valid.
*/
@@ -47,6 +64,7 @@ struct device {
uint32_t flags;
uint64_t end;
struct dm_list open_list;
+ struct dev_ext ext;
char pvid[ID_LEN + 1];
char _padding[7];
@@ -64,6 +82,15 @@ struct device_area {
};
/*
+ * Support for external device info.
+ */
+const char *dev_ext_name(struct device *dev);
+int dev_ext_enable(struct device *dev, dev_ext_t src);
+int dev_ext_disable(struct device *dev);
+struct dev_ext *dev_ext_get(struct device *dev);
+int dev_ext_release(struct device *dev);
+
+/*
* All io should use these routines.
*/
int dev_get_block_size(struct device *dev, unsigned int *phys_block_size, unsigned int *block_size);
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