[patch 22/71] block: submit_bh() inadvertently discards barrierflag on a sync write

[Greg KH]

2.6.26-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Jens Axboe <jens.axboe@xxxxxxxxxx>

commit 48fd4f93a00eac844678629f2f00518e146ed30d upstream

Reported by Milan Broz <mbroz@xxxxxxxxxx>, 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@xxxxxxxxxx>
Cc: Chuck Ebbert <cebbert@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/buffer.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2868,14 +2868,17 @@ int submit_bh(int rw, struct buffer_head
 	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);
 
 	/*

-- 
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