diff options
author | Alasdair G Kergon <agk@redhat.com> | 2011-10-31 21:19:00 +0100 |
---|---|---|
committer | Alasdair G Kergon <agk@redhat.com> | 2011-10-31 21:19:00 +0100 |
commit | 3791e2fc0e4b40d4188e79b0a99bfa6bce714a10 (patch) | |
tree | 2dc67f0593e1cb1f3dc07ff9883a03fe9edb4b2a /drivers/md/dm-table.c | |
parent | dm kcopyd: add dm_kcopyd_zero to zero an area (diff) | |
download | linux-3791e2fc0e4b40d4188e79b0a99bfa6bce714a10.tar.xz linux-3791e2fc0e4b40d4188e79b0a99bfa6bce714a10.zip |
dm table: add singleton feature
Introduce the concept of a singleton table which contains exactly one target.
If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper
will ensure that any table that includes that target contains no others.
The thin provisioning pool target uses this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-table.c')
-rw-r--r-- | drivers/md/dm-table.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 81cbbf375bd7..2ec3482e942a 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -55,6 +55,7 @@ struct dm_table { struct dm_target *targets; unsigned integrity_supported:1; + unsigned singleton:1; /* * Indicates the rw permissions for the new logical @@ -740,6 +741,12 @@ int dm_table_add_target(struct dm_table *t, const char *type, char **argv; struct dm_target *tgt; + if (t->singleton) { + DMERR("%s: target type %s must appear alone in table", + dm_device_name(t->md), t->targets->type->name); + return -EINVAL; + } + if ((r = check_space(t))) return r; @@ -758,6 +765,15 @@ int dm_table_add_target(struct dm_table *t, const char *type, return -EINVAL; } + if (dm_target_needs_singleton(tgt->type)) { + if (t->num_targets) { + DMERR("%s: target type %s must appear alone in table", + dm_device_name(t->md), type); + return -EINVAL; + } + t->singleton = 1; + } + tgt->table = t; tgt->begin = start; tgt->len = len; |