nilfs2: replace barriers with explicit flush / FUA usage

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

tj: nilfs is now fixed to wait for discard completion.  Updated this
    patch accordingly and dropped warning about it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

2 files changed, 3 insertions, 14 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 922263393c76..faa5078ff751 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -178,17 +178,9 @@ static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 
  retry:
         set_buffer_dirty(nilfs->ns_sbh[0]);
-
         if (nilfs_test_opt(sbi, BARRIER)) {
                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
-                                          WRITE_SYNC | WRITE_BARRIER);
-                if (err == -EOPNOTSUPP) {
-                        nilfs_warning(sbi->s_super, __func__,
-                                      "barrier-based sync failed. "
-                                      "disabling barriers\n");
-                        nilfs_clear_opt(sbi, BARRIER);
-                        goto retry;
-                }
+                                          WRITE_SYNC | WRITE_FLUSH_FUA);
         } else {
                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
         }
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 4317f177ea7c..400b2caef4d8 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -774,9 +774,7 @@ int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
                         ret = blkdev_issue_discard(nilfs->ns_bdev,
                                                    start * sects_per_block,
                                                    nblocks * sects_per_block,
-                                                   GFP_NOFS,
-                                                   BLKDEV_IFL_WAIT |
-                                                   BLKDEV_IFL_BARRIER);
+                                                   GFP_NOFS, BLKDEV_IFL_WAIT);
                         if (ret < 0)
                                 return ret;
                         nblocks = 0;
@@ -786,8 +784,7 @@ int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
                 ret = blkdev_issue_discard(nilfs->ns_bdev,
                                            start * sects_per_block,
                                            nblocks * sects_per_block,
-                                           GFP_NOFS,
-                                          BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
+                                           GFP_NOFS, BLKDEV_IFL_WAIT);
         return ret;
 }