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dm: set DM_TARGET_WILDCARD feature on "error" target

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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@redhat.com>
This commit is contained in:
Mike Snitzer 2016-02-06 18:38:46 -05:00
parent e522c03905
commit f083b09b78
5 changed files with 26 additions and 2 deletions
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3
drivers/md/dm-ioctl.c
View file

@ -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;

14
drivers/md/dm-table.c
View file

@ -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));

3
drivers/md/dm-target.c
View file

@ -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,

1
drivers/md/dm.h
View file

@ -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);

7
include/linux/device-mapper.h
View file

@ -189,6 +189,13 @@ struct target_type {
#define DM_TARGET_IMMUTABLE 0x00000004
#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