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authorMike Snitzer <snitzer@redhat.com>2011-05-29 15:52:55 +0400
committerAlasdair G Kergon <agk@redhat.com>2011-05-29 15:52:55 +0400
commit4c2593270133708698d4b8cea2dab469479ad13b (patch)
treef408edef9145b2f9553cbb2142347fc79023c4ff
parent139f37f5e14cd883eee2a8a36289f544b5390a44 (diff)
downloadlinux-4c2593270133708698d4b8cea2dab469479ad13b.tar.xz
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>
-rw-r--r--drivers/md/dm-table.c6
-rw-r--r--include/linux/device-mapper.h6
2 files changed, 11 insertions, 1 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index cb8380c9767f..215e112d153e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -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;
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 32a4423710f5..4427e0454051 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -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 */