diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2011-08-02 12:32:01 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2011-08-02 12:32:01 +0100 |
| commit | 936688d7eb0f39be96c5791be1a04994cc8d6aa0 (patch) | |
| tree | 4001f52284d39f5353174096e76b357f52ee2fb7 | |
| parent | 283a8328ca5b987e547848de8ff0e28edcfb9e08 (diff) | |
dm table: fix discard support
Remove 'discards_supported' from the dm_table structure. The same
information can be easily discovered from the table's target(s) in
dm_table_supports_discards().
Before this fix dm_table_supports_discards() would skip checking the
individual targets' 'discards_supported' flag if any one target in the
table didn't set num_discard_requests > 0. Now the per-target
'discards_supported' flag is effective at insuring the final DM device
advertises discard support. But, to be clear, targets that don't
support discards (!num_discard_requests) will not receive discard
requests.
Also DMWARN if a target sets 'discards_supported' override but forgets
to set 'num_discard_requests'.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
| -rw-r--r-- | drivers/md/dm-table.c | 15 | ||||
| -rw-r--r-- | drivers/md/dm.c | 3 |
2 files changed, 9 insertions, 9 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index bfe9c2333ce..3909fa259f5 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -54,7 +54,6 @@ struct dm_table { sector_t *highs; struct dm_target *targets; - unsigned discards_supported:1; unsigned integrity_supported:1; /* @@ -209,7 +208,6 @@ int dm_table_create(struct dm_table **result, fmode_t mode, INIT_LIST_HEAD(&t->devices); INIT_LIST_HEAD(&t->target_callbacks); atomic_set(&t->holders, 0); - t->discards_supported = 1; if (!num_targets) num_targets = KEYS_PER_NODE; @@ -791,8 +789,9 @@ int dm_table_add_target(struct dm_table *t, const char *type, t->highs[t->num_targets++] = tgt->begin + tgt->len - 1; - if (!tgt->num_discard_requests) - t->discards_supported = 0; + if (!tgt->num_discard_requests && tgt->discards_supported) + DMWARN("%s: %s: ignoring discards_supported because num_discard_requests is zero.", + dm_device_name(t->md), type); return 0; @@ -1359,19 +1358,19 @@ bool dm_table_supports_discards(struct dm_table *t) struct dm_target *ti; unsigned i = 0; - if (!t->discards_supported) - return 0; - /* * 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. + * supporting discard selectively must provide. */ while (i < dm_table_get_num_targets(t)) { ti = dm_table_get_target(t, i++); + if (!ti->num_discard_requests) + continue; + if (ti->discards_supported) return 1; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 41abc6dd481..aeb0fa1ccfe 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1179,7 +1179,8 @@ static int __clone_and_map_discard(struct clone_info *ci) /* * Even though the device advertised discard support, - * reconfiguration might have changed that since the + * that does not mean every target supports it, and + * reconfiguration might also have changed that since the * check was performed. */ if (!ti->num_discard_requests) |