[Cluster-devel] [PATCH 1/2] gfs2: Clean up freeing struct gfs2_sbd

[Cluster-devel] [PATCH 1/2] gfs2: Clean up freeing struct gfs2_sbd

[Andreas Gruenbacher]

Add a free_sbd function for freeing a struct gfs2_sbd.  Use that for
freeing a super-block descriptor, either directly or via kobject_put.
Free sd_lkstats inside the kobject release function: that way,
gfs2_put_super will no longer leak sd_lkstats.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/gfs2/ops_fstype.c | 23 ++++++++++++++---------
 fs/gfs2/super.h      |  2 ++
 fs/gfs2/sys.c        |  3 +--
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 46f6615eaf12..f5312f3b58ee 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -64,6 +64,13 @@ static void gfs2_tune_init(struct gfs2_tune *gt)
 	gt->gt_complain_secs = 10;
 }
 
+void free_sbd(struct gfs2_sbd *sdp)
+{
+	if (sdp->sd_lkstats)
+		free_percpu(sdp->sd_lkstats);
+	kfree(sdp);
+}
+
 static struct gfs2_sbd *init_sbd(struct super_block *sb)
 {
 	struct gfs2_sbd *sdp;
@@ -75,10 +82,8 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
 
 	sdp->sd_vfs = sb;
 	sdp->sd_lkstats = alloc_percpu(struct gfs2_pcpu_lkstats);
-	if (!sdp->sd_lkstats) {
-		kfree(sdp);
-		return NULL;
-	}
+	if (!sdp->sd_lkstats)
+		goto fail;
 	sb->s_fs_info = sdp;
 
 	set_bit(SDF_NOJOURNALID, &sdp->sd_flags);
@@ -137,8 +142,11 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
 	mutex_init(&sdp->sd_freeze_mutex);
 
 	return sdp;
-}
 
+fail:
+	free_sbd(sdp);
+	return NULL;
+}
 
 /**
  * gfs2_check_sb - Check superblock
@@ -1089,8 +1097,7 @@ static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent
 	if (error) {
 		/* In this case, we haven't initialized sysfs, so we have to
 		   manually free the sdp. */
-		free_percpu(sdp->sd_lkstats);
-		kfree(sdp);
+		free_sbd(sdp);
 		sb->s_fs_info = NULL;
 		return error;
 	}
@@ -1193,7 +1200,6 @@ static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent
 	gfs2_lm_unmount(sdp);
 fail_debug:
 	gfs2_delete_debugfs_file(sdp);
-	free_percpu(sdp->sd_lkstats);
 	/* gfs2_sys_fs_del must be the last thing we do, since it causes
 	 * sysfs to call function gfs2_sbd_release, which frees sdp. */
 	gfs2_sys_fs_del(sdp);
@@ -1373,7 +1379,6 @@ static void gfs2_kill_sb(struct super_block *sb)
 	sdp->sd_root_dir = NULL;
 	sdp->sd_master_dir = NULL;
 	shrink_dcache_sb(sb);
-	free_percpu(sdp->sd_lkstats);
 	kill_block_super(sb);
 }
 
diff --git a/fs/gfs2/super.h b/fs/gfs2/super.h
index 73c97dccae21..720d257371b5 100644
--- a/fs/gfs2/super.h
+++ b/fs/gfs2/super.h
@@ -47,6 +47,8 @@ extern void update_statfs(struct gfs2_sbd *sdp, struct buffer_head *m_bh,
 extern int gfs2_statfs_sync(struct super_block *sb, int type);
 extern void gfs2_freeze_func(struct work_struct *work);
 
+extern void free_sbd(struct gfs2_sbd *sdp);
+
 extern struct file_system_type gfs2_fs_type;
 extern struct file_system_type gfs2meta_fs_type;
 extern const struct export_operations gfs2_export_ops;
diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index 08e4996adc23..348903010911 100644
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -304,7 +304,7 @@ static void gfs2_sbd_release(struct kobject *kobj)
 {
 	struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
 
-	kfree(sdp);
+	free_sbd(sdp);
 }
 
 static struct kobj_type gfs2_ktype = {
@@ -682,7 +682,6 @@ int gfs2_sys_fs_add(struct gfs2_sbd *sdp)
 fail_tune:
 	sysfs_remove_group(&sdp->sd_kobj, &tune_group);
 fail_reg:
-	free_percpu(sdp->sd_lkstats);
 	fs_err(sdp, "error %d adding sysfs files\n", error);
 	kobject_put(&sdp->sd_kobj);
 	sb->s_fs_info = NULL;
-- 
2.20.1

[Cluster-devel] [PATCH 2/2] gfs2: Fix sign extension error in gfs2_update_stats

[Andreas Gruenbacher]

Commit 4d207133e9c3 changed the types of the statistic values in struct
gfs2_lkstats from s64 to u64.  Because of that, what should be a signed
value in gfs2_update_stats turned into an unsigned value.  When shifted
right, we end up with a large positive value instead of a small negative
value, which results in an incorrect variance estimate.

Fixes: 4d207133e9c3 ("gfs2: Make statistics unsigned, suitable for use with do_div()")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/gfs2/lock_dlm.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
index 31df26ed7854..69bd1597bacf 100644
--- a/fs/gfs2/lock_dlm.c
+++ b/fs/gfs2/lock_dlm.c
@@ -31,9 +31,10 @@
  * @delta is the difference between the current rtt sample and the
  * running average srtt. We add 1/8 of that to the srtt in order to
  * update the current srtt estimate. The variance estimate is a bit
- * more complicated. We subtract the abs value of the @delta from
- * the current variance estimate and add 1/4 of that to the running
- * total.
+ * more complicated. We subtract the current variance estimate from
+ * the abs value of the @delta and add 1/4 of that to the running
+ * total.  That's equivalent to 3/4 of the current variance
+ * estimate plus 1/4 of the abs of @delta.
  *
  * Note that the index points at the array entry containing the smoothed
  * mean value, and the variance is always in the following entry
@@ -49,7 +50,7 @@ static inline void gfs2_update_stats(struct gfs2_lkstats *s, unsigned index,
 	s64 delta = sample - s->stats[index];
 	s->stats[index] += (delta >> 3);
 	index++;
-	s->stats[index] += ((abs(delta) - s->stats[index]) >> 2);
+	s->stats[index] += (s64)(abs(delta) - s->stats[index]) >> 2;
 }
 
 /**
-- 
2.20.1