dm table: allow targets to support discards internally

Permit a target to support discards regardless of whether or not all its
underlying devices do.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mike Snitzer 2011-05-29 12:52:55 +01:00 committed by Alasdair G Kergon
parent 139f37f5e1
commit 4c25932701
2 changed files with 11 additions and 1 deletions

View File

@ -1346,7 +1346,8 @@ bool dm_table_supports_discards(struct dm_table *t)
return 0;
/*
* Ensure that at least one underlying device supports discards.
* Unless any target used by the table set discards_supported,
* require at least one underlying device to support discards.
* t->devices includes internal dm devices such as mirror logs
* so we need to use iterate_devices here, which targets
* supporting discard must provide.
@ -1354,6 +1355,9 @@ bool dm_table_supports_discards(struct dm_table *t)
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
if (ti->discards_supported)
return 1;
if (ti->type->iterate_devices &&
ti->type->iterate_devices(ti, device_discard_capable, NULL))
return 1;

View File

@ -191,6 +191,12 @@ struct dm_target {
/* Used to provide an error string from the ctr */
char *error;
/*
* Set if this target needs to receive discards regardless of
* whether or not its underlying devices have support.
*/
unsigned discards_supported:1;
};
/* Each target can link one of these into the table */