[Cluster-devel] GFS2: introduce AIL lock

[Steven Whitehouse]

Hi,

On Mon, 2011-03-14 at 09:44 +1100, Dave Chinner wrote:
> On Fri, Mar 11, 2011 at 12:23:42PM +0000, Steven Whitehouse wrote:
> > Hi,
> > 
> > I'm not sure how this patch got missed out, but for some reason I didn't
> > pick it up originally. This is a port of the original patch to the
> > latest upstream kernel, plus a couple of tweeks that I suggested in the
> > original review.
> 
> Ah, I thought you took it in with the other patches at the time, so
> I didn't follow up. Oh well, at lesat it didn't quite fall through
> the crack.
> 
Me too :( I discovered it when I was reviewing your comments while
investigating performance issues.

> > Dave, if you've no objections, then I'd like to push this into my -nmw
> > git tree for the next merge.
> 
> No objections. I just did a quick check of the patch again and I
> can't see anything obviously wrong with it, so queue it up ;)
> 
> Cheers,
> 
> Dave.
Ok, done. Also I'm intending to add the below to cover a few loose ends
which I found on Friday. I think it should be good to go after then,


Steve.


>From c618e87a5fd02aaad006c12d5a80a231dfa39250 Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho at redhat.com>
Date: Mon, 14 Mar 2011 12:40:29 +0000
Subject: [PATCH] GFS2: Update to AIL list locking

The previous patch missed a couple of places where the AIL list
needed locking, so this fixes up those places, plus a comment
is corrected too.

Signed-off-by: Steven Whitehouse <swhiteho at redhat.com>
Cc: Dave Chinner <dchinner at redhat.com>

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 4e3c044..e7ed31f 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -67,7 +67,7 @@ unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
  * @mapping: The associated mapping (maybe NULL)
  * @bd: The gfs2_bufdata to remove
  *
- * The log lock _must_ be held when calling this function
+ * The ail lock _must_ be held when calling this function
  *
  */
 
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 4295a6a..e919abf 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -51,8 +51,10 @@ static void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
 	/* If this buffer is in the AIL and it has already been written
 	 * to in-place disk block, remove it from the AIL.
 	 */
+	spin_lock(&sdp->sd_ail_lock);
 	if (bd->bd_ail)
 		list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
+	spin_unlock(&sdp->sd_ail_lock);
 	get_bh(bh);
 	atomic_inc(&sdp->sd_log_pinned);
 	trace_gfs2_pin(bd, 1);
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 939739c..01d97f4 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -326,6 +326,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
 		brelse(bh);
 	}
 	if (bd) {
+		spin_lock(&sdp->sd_ail_lock);
 		if (bd->bd_ail) {
 			gfs2_remove_from_ail(bd);
 			bh->b_private = NULL;
@@ -333,6 +334,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
 			bd->bd_blkno = bh->b_blocknr;
 			gfs2_trans_add_revoke(sdp, bd);
 		}
+		spin_unlock(&sdp->sd_ail_lock);
 	}
 	clear_buffer_dirty(bh);
 	clear_buffer_uptodate(bh);
-- 
1.7.4