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authorMike Snitzer <snitzer@redhat.com>2011-08-02 12:32:01 +0100
committerAlasdair G Kergon <agk@redhat.com>2011-08-02 12:32:01 +0100
commit936688d7eb0f39be96c5791be1a04994cc8d6aa0 (patch)
tree4001f52284d39f5353174096e76b357f52ee2fb7 /drivers/md/dm.c
parent283a8328ca5b987e547848de8ff0e28edcfb9e08 (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>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c3
1 files changed, 2 insertions, 1 deletions
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)