From: NeilBrown <neilb@suse.de>
Date: Fri, 9 Jul 2010 12:02:50 +0000 (+1000)
Subject: Make sure we retry orphan handling if mutex unavailable.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=f3774db5d6d9edfbf464c76be69d2b1711d11c2a;p=LaFS.git

Make sure we retry orphan handling if mutex unavailable.

We cannot arrange for a wakeup when i_mutex is dropped,
so we need to set a short timeout when i_mutex cannot be
claimed.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/orphan.c b/orphan.c
index 69464d0..1abe643 100644
--- a/orphan.c
+++ b/orphan.c
@@ -460,6 +460,8 @@ long lafs_run_orphans(struct fs *fs)
 {
 	struct datablock *db;
 	struct list_head done;
+	long timeout = MAX_SCHEDULE_TIMEOUT;
+
 	if (list_empty_careful(&fs->pending_orphans))
 		return MAX_SCHEDULE_TIMEOUT;
 
@@ -480,8 +482,14 @@ long lafs_run_orphans(struct fs *fs)
 		mx = orphan_mutex(db);
 		if (!mx && !test_bit(B_Claimed, &db->b.flags))
 			/* OK not to have a mutex */;
-		else if (!mx || !mutex_trylock(mx))
+		else if (!mx || !mutex_trylock(mx)) {
+			/* we cannot get a wakeup when mutex
+			 * is unlocked, so we need timeout
+			 * FIXME this is unfortunate
+			 */
+			timeout = msecs_to_jiffies(500);
 			continue;
+		}
 		getdref(db, MKREF(run_orphans));
 		spin_unlock(&fs->lock);
 
@@ -517,7 +525,7 @@ long lafs_run_orphans(struct fs *fs)
 	if (list_empty_careful(&fs->pending_orphans))
 		/* unmount might be waiting... */
 		wake_up(&fs->async_complete);
-	return MAX_SCHEDULE_TIMEOUT;
+	return timeout;
 }
 
 int lafs_drop_orphan(struct fs *fs, struct datablock *db)