drbd: REQ_HARDBARRIER -> REQ_FUA transition for meta data accesses

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

3 files changed, 7 insertions, 20 deletions

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index bd925180a2b0..ba95cba192be 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -78,11 +78,10 @@ static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
         init_completion(&md_io.event);
         md_io.error = 0;
 
-        if ((rw & WRITE) && !test_bit(MD_NO_BARRIER, &mdev->flags))
-                rw |= REQ_HARDBARRIER;
+        if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
+                rw |= REQ_FUA;
         rw |= REQ_UNPLUG | REQ_SYNC;
 
- retry:
         bio = bio_alloc(GFP_NOIO, 1);
         bio->bi_bdev = bdev->md_bdev;
         bio->bi_sector = sector;
@@ -100,17 +99,6 @@ static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
         wait_for_completion(&md_io.event);
         ok = bio_flagged(bio, BIO_UPTODATE) && md_io.error == 0;
 
-        /* check for unsupported barrier op.
-         * would rather check on EOPNOTSUPP, but that is not reliable.
-         * don't try again for ANY return value != 0 */
-        if (unlikely((bio->bi_rw & REQ_HARDBARRIER) && !ok)) {
-                /* Try again with no barrier */
-                dev_warn(DEV, "Barriers not supported on meta data device - disabling\n");
-                set_bit(MD_NO_BARRIER, &mdev->flags);
-                rw &= ~REQ_HARDBARRIER;
-                bio_put(bio);
-                goto retry;
-        }
  out:
         bio_put(bio);
         return ok;
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 1b915fd9278f..575bfba1b0da 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -835,8 +835,7 @@ enum {
         NO_BARRIER_SUPP,        /* underlying block device doesn't implement barriers */
         CONSIDER_RESYNC,
 
-        MD_NO_BARRIER,          /* meta data device does not support barriers,
-                                   so don't even try */
+        MD_NO_FUA,              /* Users wants us to not use FUA/FLUSH on meta data dev */
         SUSPEND_IO,             /* suspend application io */
         BITMAP_IO,              /* suspend application io;
                                    once no more io in flight, start bitmap io */
@@ -2404,13 +2403,13 @@ static inline void drbd_md_flush(struct drbd_conf *mdev)
 {
         int r;
 
-        if (test_bit(MD_NO_BARRIER, &mdev->flags))
+        if (test_bit(MD_NO_FUA, &mdev->flags))
                 return;
 
         r = blkdev_issue_flush(mdev->ldev->md_bdev, GFP_KERNEL, NULL,
                         BLKDEV_IFL_WAIT);
         if (r) {
-                set_bit(MD_NO_BARRIER, &mdev->flags);
+                set_bit(MD_NO_FUA, &mdev->flags);
                 dev_err(DEV, "meta data flush failed with status %d, disabling md-flushes\n", r);
         }
 }
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 899878fcf97d..29e5c70e4e26 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1103,9 +1103,9 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         /* Reset the "barriers don't work" bits here, then force meta data to
          * be written, to ensure we determine if barriers are supported. */
         if (nbc->dc.no_md_flush)
-                set_bit(MD_NO_BARRIER, &mdev->flags);
+                set_bit(MD_NO_FUA, &mdev->flags);
         else
-                clear_bit(MD_NO_BARRIER, &mdev->flags);
+                clear_bit(MD_NO_FUA, &mdev->flags);
 
         /* Point of no return reached.
          * Devices and memory are no longer released by error cleanup below.