The DM_TARGET_WILDCARD feature indicates that the "error" target may
replace any target; even immutable targets. This feature will be useful
to preserve the ability to replace the "multipath" target even once it
is formally converted over to having the DM_TARGET_IMMUTABLE feature.
Also, implicit in the DM_TARGET_WILDCARD feature flag being set is that
.map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined
in the target_type.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-ioctl.c | 3 ++-
drivers/md/dm-table.c | 14 ++++++++++++++
drivers/md/dm-target.c | 3 ++-
drivers/md/dm.h | 1 +
include/linux/device-mapper.h | 7 +++++++
5 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 80a4395..4763c4a 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1291,7 +1291,8 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
immutable_target_type = dm_get_immutable_target_type(md);
if (immutable_target_type &&
- (immutable_target_type != dm_table_get_immutable_target_type(t))) {
+ (immutable_target_type != dm_table_get_immutable_target_type(t)) &&
+ !dm_table_get_wildcard_target(t)) {
DMWARN("can't replace immutable target type %s",
immutable_target_type->name);
r = -EINVAL;
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 061152a..a49e62b 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -920,6 +920,20 @@ struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
return t->immutable_target_type;
}
+struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
+{
+ struct dm_target *uninitialized_var(ti);
+ unsigned i = 0;
+
+ while (i < dm_table_get_num_targets(t)) {
+ ti = dm_table_get_target(t, i++);
+ if (dm_target_is_wildcard(ti->type))
+ return ti;
+ }
+
+ return NULL;
+}
+
bool dm_table_request_based(struct dm_table *t)
{
return __table_type_request_based(dm_table_get_type(t));
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index 925ec1b..a317dd8 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -150,7 +150,8 @@ static void io_err_release_clone_rq(struct request *clone)
static struct target_type error_target = {
.name = "error",
- .version = {1, 3, 0},
+ .version = {1, 4, 0},
+ .features = DM_TARGET_WILDCARD,
.ctr = io_err_ctr,
.dtr = io_err_dtr,
.map = io_err_map,
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 7edcf97..53df258 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -73,6 +73,7 @@ int dm_table_resume_targets(struct dm_table *t);
int dm_table_any_congested(struct dm_table *t, int bdi_bits);
unsigned dm_table_get_type(struct dm_table *t);
struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
+struct dm_target *dm_table_get_wildcard_target(struct dm_table *t);
bool dm_table_request_based(struct dm_table *t);
bool dm_table_mq_request_based(struct dm_table *t);
void dm_table_free_md_mempools(struct dm_table *t);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index ec1c61c..87d50ec 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -190,6 +190,13 @@ struct target_type {
#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
/*
+ * Indicates that a target may replace any target; even immutable targets.
+ * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
+ */
+#define DM_TARGET_WILDCARD 0x00000008
+#define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
+
+/*
* Some targets need to be sent the same WRITE bio severals times so
* that they can send copies of it to different devices. This function
* examines any supplied bio and returns the number of copies of it the
--
2.5.4 (Apple Git-61)
--
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