Re: [PATCH 07/15] nilfs2: replace barriers with explicit flush / FUA usage

[Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>]

On Wed, 18 Aug 2010 05:29:15 -0400, Christoph Hellwig wrote:
> Switch to the WRITE_FLUSH_FUA flag for log writes, remove the EOPNOTSUPP
> detection for barriers and stop setting the barrier flag for discards.
> 
> XXX: nilfs2 does not actually wait for discards to finish, so the code
> after this patch is almost guaranteed to be incorrect when dicards are
> used.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Ahh, actually discards in nilfs missed adoption of wait semantics, and
should be corrected.

May I send up the following fix on ahead ?

As for the rest, the patch looks ok to me.

Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Thanks,
Ryusuke Konishi

---
From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: wait for discard to finish

nilfs_discard_segment() doesn't wait for completion of discard
requests.  This specifies BLKDEV_IFL_WAIT flag when calling
blkdev_issue_discard() in order to fix the sync failure.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@lst.de>
---
 fs/nilfs2/the_nilfs.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 6af1c00..4317f17 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -775,6 +775,7 @@ int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
 						   start * sects_per_block,
 						   nblocks * sects_per_block,
 						   GFP_NOFS,
+						   BLKDEV_IFL_WAIT |
 						   BLKDEV_IFL_BARRIER);
 			if (ret < 0)
 				return ret;
@@ -785,7 +786,8 @@ 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_BARRIER);
+					   GFP_NOFS,
+					  BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
 	return ret;
 }
 
-- 
1.6.6.2