block: submit_bh() inadvertently discards barrier flag on a sync write

Reported by Milan Broz <mbroz@redhat.com>, commit 18ce3751 inadvertently
made submit_bh() discard the barrier bit for a WRITE_SYNC request. Fix
that up.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 38653e36e225..ac78d4c19b3b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2926,14 +2926,17 @@ int submit_bh(int rw, struct buffer_head * bh)
         BUG_ON(!buffer_mapped(bh));
         BUG_ON(!bh->b_end_io);
 
-        if (buffer_ordered(bh) && (rw == WRITE))
-                rw = WRITE_BARRIER;
+        /*
+         * Mask in barrier bit for a write (could be either a WRITE or a
+         * WRITE_SYNC
+         */
+        if (buffer_ordered(bh) && (rw & WRITE))
+                rw |= WRITE_BARRIER;
 
         /*
-         * Only clear out a write error when rewriting, should this
-         * include WRITE_SYNC as well?
+         * Only clear out a write error when rewriting
          */
-        if (test_set_buffer_req(bh) && (rw == WRITE || rw == WRITE_BARRIER))
+        if (test_set_buffer_req(bh) && (rw & WRITE))
                 clear_buffer_write_io_error(bh);
 
         /*