[PATCH 05/15] gfs2: replace barriers with explicit flush / FUA usage

[Christoph Hellwig <hch@infradead.org>]

[-- Attachment #1: gfs2-use-flush-fua --]
[-- Type: text/plain, Size: 2006 bytes --]

Switch to the WRITE_FLUSH_FUA flag for log writes, remove the EOPNOTSUPP
detection for barriers and stop setting the barrier flag for discards.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/gfs2/log.c
===================================================================
--- linux-2.6.orig/fs/gfs2/log.c	2010-08-17 16:19:53.597003932 +0200
+++ linux-2.6/fs/gfs2/log.c	2010-08-17 16:22:04.889005329 +0200
@@ -592,22 +592,13 @@ static void log_write_header(struct gfs2
 	lh->lh_hash = cpu_to_be32(hash);
 
 	bh->b_end_io = end_buffer_write_sync;
-	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
-		goto skip_barrier;
 	get_bh(bh);
-	submit_bh(WRITE_BARRIER | REQ_META, bh);
-	wait_on_buffer(bh);
-	if (buffer_eopnotsupp(bh)) {
-		clear_buffer_eopnotsupp(bh);
-		set_buffer_uptodate(bh);
-		fs_info(sdp, "barrier sync failed - disabling barriers\n");
-		set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
-		lock_buffer(bh);
-skip_barrier:
-		get_bh(bh);
+	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
 		submit_bh(WRITE_SYNC | REQ_META, bh);
-		wait_on_buffer(bh);
-	}
+	else
+		submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
+	wait_on_buffer(bh);
+
 	if (!buffer_uptodate(bh))
 		gfs2_io_error_bh(sdp, bh);
 	brelse(bh);
Index: linux-2.6/fs/gfs2/rgrp.c
===================================================================
--- linux-2.6.orig/fs/gfs2/rgrp.c	2010-08-17 16:21:23.626253967 +0200
+++ linux-2.6/fs/gfs2/rgrp.c	2010-08-17 16:21:39.702005748 +0200
@@ -854,8 +854,7 @@ static void gfs2_rgrp_send_discards(stru
 				if ((start + nr_sects) != blk) {
 					rv = blkdev_issue_discard(bdev, start,
 							    nr_sects, GFP_NOFS,
-							    BLKDEV_IFL_WAIT |
-							    BLKDEV_IFL_BARRIER);
+							    BLKDEV_IFL_WAIT);
 					if (rv)
 						goto fail;
 					nr_sects = 0;
@@ -870,7 +869,7 @@ start_new_extent:
 	}
 	if (nr_sects) {
 		rv = blkdev_issue_discard(bdev, start, nr_sects, GFP_NOFS,
-					 BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
+					 BLKDEV_IFL_WAIT);
 		if (rv)
 			goto fail;
 	}