md: linear supports TRIM

This makes md linear support TRIM.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 92c64d162a92..21014836bdbf 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -138,6 +138,7 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
         struct linear_conf *conf;
         struct md_rdev *rdev;
         int i, cnt;
+        bool discard_supported = false;
 
         conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info),
                         GFP_KERNEL);
@@ -171,6 +172,8 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
                 conf->array_sectors += rdev->sectors;
                 cnt++;
 
+                if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
+                        discard_supported = true;
         }
         if (cnt != raid_disks) {
                 printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n",
@@ -178,6 +181,11 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
                 goto out;
         }
 
+        if (!discard_supported)
+                queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+        else
+                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+
         /*
          * Here we calculate the device offsets.
          */
@@ -331,6 +339,14 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
         bio->bi_sector = bio->bi_sector - start_sector
                 + tmp_dev->rdev->data_offset;
         rcu_read_unlock();
+
+        if (unlikely((bio->bi_rw & REQ_DISCARD) &&
+                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) {
+                /* Just ignore it */
+                bio_endio(bio, 0);
+                return;
+        }
+
         generic_make_request(bio);
 }