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| author | Mike Snitzer <snitzer@redhat.com> | 2010-08-12 04:14:01 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2010-08-12 04:14:01 +0100 |
| commit | a5664dad7e1a278d2915c2bf79cf42250e12d7db (patch) | |
| tree | 3bdbe17f12376c63ea05100c2597757e01dc95e2 /drivers/md/dm.h | |
| parent | 708e929513502fb050c0a3c3ee267cab5b056ded (diff) | |
| download | lwn-a5664dad7e1a278d2915c2bf79cf42250e12d7db.tar.gz lwn-a5664dad7e1a278d2915c2bf79cf42250e12d7db.zip | |
dm ioctl: make bio or request based device type immutable
Determine whether a mapped device is bio-based or request-based when
loading its first (inactive) table and don't allow that to be changed
later.
This patch performs different device initialisation in each of the two
cases. (We don't think it's necessary to add code to support changing
between the two types.)
Allowed md->type transitions:
DM_TYPE_NONE to DM_TYPE_BIO_BASED
DM_TYPE_NONE to DM_TYPE_REQUEST_BASED
We now prevent table_load from replacing the inactive table with a
conflicting type of table even after an explicit table_clear.
Introduce 'type_lock' into the struct mapped_device to protect md->type
and to prepare for the next patch that will change the queue
initialization and allocate memory while md->type_lock is held.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
drivers/md/dm-ioctl.c | 15 +++++++++++++++
drivers/md/dm.c | 37 ++++++++++++++++++++++++++++++-------
drivers/md/dm.h | 5 +++++
include/linux/dm-ioctl.h | 4 ++--
4 files changed, 52 insertions(+), 9 deletions(-)
Diffstat (limited to 'drivers/md/dm.h')
| -rw-r--r-- | drivers/md/dm.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 8223671e4901..1db782530ce6 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -66,6 +66,11 @@ int dm_table_alloc_md_mempools(struct dm_table *t); void dm_table_free_md_mempools(struct dm_table *t); struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t); +void dm_lock_md_type(struct mapped_device *md); +void dm_unlock_md_type(struct mapped_device *md); +void dm_set_md_type(struct mapped_device *md, unsigned type); +unsigned dm_get_md_type(struct mapped_device *md); + /* * To check the return value from dm_table_find_target(). */ |