GFS2: Clean up & move gfs2_quotad

This patch is a clean up of gfs2_quotad prior to giving it an
extra job to do in addition to the current portfolio of updating
the quota and statfs information from time to time.

As a result it has been moved into quota.c allowing one of the
functions it calls to be made static. Also the clean up allows
the two existing functions to have separate timeouts and also
to coexist with its future role of dealing with the "truncate in
progress" inode flag.

The (pointless) setting of gfs2_quotad_secs is removed since we
arrange to only wake up quotad when one of the two timers expires.

In addition the struct gfs2_quota_data is moved into a slab cache,
mainly for easier debugging. It should also be possible to use
a shrinker in the future, rather than the current scheme of scanning
the quota data entries from time to time.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 70 insertions, 6 deletions

diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 228a46596188..0cfe44f0b6ab 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -46,6 +46,8 @@
 #include <linux/bio.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/lm_interface.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -94,7 +96,7 @@ static int qd_alloc(struct gfs2_sbd *sdp, int user, u32 id,
 	struct gfs2_quota_data *qd;
 	int error;
 
-	qd = kzalloc(sizeof(struct gfs2_quota_data), GFP_NOFS);
+	qd = kmem_cache_zalloc(gfs2_quotad_cachep, GFP_NOFS);
 	if (!qd)
 		return -ENOMEM;
 
@@ -119,7 +121,7 @@ static int qd_alloc(struct gfs2_sbd *sdp, int user, u32 id,
 	return 0;
 
 fail:
-	kfree(qd);
+	kmem_cache_free(gfs2_quotad_cachep, qd);
 	return error;
 }
 
@@ -158,7 +160,7 @@ static int qd_get(struct gfs2_sbd *sdp, int user, u32 id, int create,
 		if (qd || !create) {
 			if (new_qd) {
 				gfs2_lvb_unhold(new_qd->qd_gl);
-				kfree(new_qd);
+				kmem_cache_free(gfs2_quotad_cachep, new_qd);
 			}
 			*qdp = qd;
 			return 0;
@@ -1195,7 +1197,7 @@ fail:
 	return error;
 }
 
-void gfs2_quota_scan(struct gfs2_sbd *sdp)
+static void gfs2_quota_scan(struct gfs2_sbd *sdp)
 {
 	struct gfs2_quota_data *qd, *safe;
 	LIST_HEAD(dead);
@@ -1222,7 +1224,7 @@ void gfs2_quota_scan(struct gfs2_sbd *sdp)
 		gfs2_assert_warn(sdp, !qd->qd_bh_count);
 
 		gfs2_lvb_unhold(qd->qd_gl);
-		kfree(qd);
+		kmem_cache_free(gfs2_quotad_cachep, qd);
 	}
 }
 
@@ -1257,7 +1259,7 @@ void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
 		gfs2_assert_warn(sdp, !qd->qd_bh_count);
 
 		gfs2_lvb_unhold(qd->qd_gl);
-		kfree(qd);
+		kmem_cache_free(gfs2_quotad_cachep, qd);
 
 		spin_lock(&sdp->sd_quota_spin);
 	}
@@ -1272,3 +1274,65 @@ void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
 	}
 }
 
+static void quotad_error(struct gfs2_sbd *sdp, const char *msg, int error)
+{
+	if (error == 0 || error == -EROFS)
+		return;
+	if (!test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
+		fs_err(sdp, "gfs2_quotad: %s error %d\n", msg, error);
+}
+
+static void quotad_check_timeo(struct gfs2_sbd *sdp, const char *msg,
+			       int (*fxn)(struct gfs2_sbd *sdp),
+			       unsigned long t, unsigned long *timeo,
+			       unsigned int *new_timeo)
+{
+	if (t >= *timeo) {
+		int error = fxn(sdp);
+		quotad_error(sdp, msg, error);
+		*timeo = gfs2_tune_get_i(&sdp->sd_tune, new_timeo) * HZ;
+	} else {
+		*timeo -= t;
+	}
+}
+
+/**
+ * gfs2_quotad - Write cached quota changes into the quota file
+ * @sdp: Pointer to GFS2 superblock
+ *
+ */
+
+int gfs2_quotad(void *data)
+{
+	struct gfs2_sbd *sdp = data;
+	struct gfs2_tune *tune = &sdp->sd_tune;
+	unsigned long statfs_timeo = 0;
+	unsigned long quotad_timeo = 0;
+	unsigned long t = 0;
+	DEFINE_WAIT(wait);
+
+	while (!kthread_should_stop()) {
+
+		/* Update the master statfs file */
+		quotad_check_timeo(sdp, "statfs", gfs2_statfs_sync, t,
+				   &statfs_timeo, &tune->gt_statfs_quantum);
+
+		/* Update quota file */
+		quotad_check_timeo(sdp, "sync", gfs2_quota_sync, t,
+				   &quotad_timeo, &tune->gt_quota_quantum);
+
+		/* FIXME: This should be turned into a shrinker */
+		gfs2_quota_scan(sdp);
+
+		if (freezing(current))
+			refrigerator();
+		t = min(quotad_timeo, statfs_timeo);
+
+		prepare_to_wait(&sdp->sd_quota_wait, &wait, TASK_UNINTERRUPTIBLE);
+		t -= schedule_timeout(t);
+		finish_wait(&sdp->sd_quota_wait, &wait);
+	}
+
+	return 0;
+}
+