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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 03-18-2010, 12:58 PM
Milan Broz
 
Default 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

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