Linux Archive

Linux Archive (http://www.linux-archive.org/)
-   Device-mapper Development (http://www.linux-archive.org/device-mapper-development/)
-   -   Add genhd flag requesting notification of partition changes only. (http://www.linux-archive.org/device-mapper-development/343565-add-genhd-flag-requesting-notification-partition-changes-only.html)

Milan Broz 03-18-2010 12:58 PM

Add genhd flag requesting notification of partition changes only.
 
This patch provides notification mechanism which allows handle partition
code in userspace.

If the BLKRRPART ioctl arrives and GENHD_FL_PARTITION_CHANGE_NOTIFY
is set, just send uevent and ignore in-kernel partitioning code.

This is useful e.g. for device-mapper devices, which can use kpartx
or similar tool in udev rules.

Signed-off-by: Milan Broz <mbroz@redhat.com>
---
block/ioctl.c | 3 ++-
drivers/md/dm.c | 1 +
fs/partitions/check.c | 6 ++++++
include/linux/genhd.h | 8 ++++++++
4 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index be48ea5..77faed3 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -101,7 +101,8 @@ static int blkdev_reread_part(struct block_device *bdev)
struct gendisk *disk = bdev->bd_disk;
int res;

- if (!disk_partitionable(disk) || bdev != bdev->bd_contains)
+ if (!disk_userspace_partitions(disk) &&
+ (!disk_partitionable(disk) || bdev != bdev->bd_contains))
return -EINVAL;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7b364d7..57da1f7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1934,6 +1934,7 @@ static struct mapped_device *alloc_dev(int minor)
md->disk->private_data = md;
sprintf(md->disk->disk_name, "dm-%d", minor);
md->disk->flags |= GENHD_FL_SUPPRESS_ADD_EVENT;
+ md->disk->flags |= GENHD_FL_PARTITION_CHANGE_NOTIFY;
add_disk(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 916173b..b66253f 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -548,6 +548,12 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
struct parsed_partitions *state;
int p, highest, res;

+ /* partitions handled in userspace, just send change event */
+ if (disk_userspace_partitions(disk)) {
+ kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+ return 0;
+ }
+
if (bdev->bd_part_count)
return -EBUSY;
res = invalidate_partition(disk, 0);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index ade71ff..64b25f0 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -118,6 +118,9 @@ struct hd_struct {
#define GENHD_FL_NATIVE_CAPACITY 128
#define GENHD_FL_SUPPRESS_ADD_EVENT 256

+/* notify udev instead of use in-kernel partitioning */
+#define GENHD_FL_PARTITION_CHANGE_NOTIFY 512
+
#define BLK_SCSI_MAX_CMDS (256)
#define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))

@@ -182,6 +185,11 @@ static inline struct gendisk *part_to_disk(struct hd_struct *part)
return NULL;
}

+static inline bool disk_userspace_partitions(struct gendisk *disk)
+{
+ return (disk->flags & GENHD_FL_PARTITION_CHANGE_NOTIFY) ? 1 : 0;
+}
+
static inline int disk_max_parts(struct gendisk *disk)
{
if (disk->flags & GENHD_FL_EXT_DEVT)
--
1.7.0

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


All times are GMT. The time now is 09:34 PM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.