From 8fb85072acc97528fe7725c38290d84ac873415e Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Tue, 10 Jan 2012 18:22:25 +0100
Subject: [PATCH] --- yaml --- r: 283218 b: refs/heads/master c:
 eaf5f9073533cde21c7121c136f1c3f072d9cf59 h: refs/heads/master v: v3

---
 [refs]                       |  2 +-
 trunk/fs/dcache.c            | 15 +++++++++++----
 trunk/include/linux/dcache.h |  1 +
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index b117f14c9eda..f62e884ba2fe 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f4947fbce208990266920d51837e4e7ba9779db1
+refs/heads/master: eaf5f9073533cde21c7121c136f1c3f072d9cf59
diff --git a/trunk/fs/dcache.c b/trunk/fs/dcache.c
index 3c6d3113a255..616fedff011a 100644
--- a/trunk/fs/dcache.c
+++ b/trunk/fs/dcache.c
@@ -243,6 +243,7 @@ static void dentry_lru_add(struct dentry *dentry)
 static void __dentry_lru_del(struct dentry *dentry)
 {
 	list_del_init(&dentry->d_lru);
+	dentry->d_flags &= ~DCACHE_SHRINK_LIST;
 	dentry->d_sb->s_nr_dentry_unused--;
 	dentry_stat.nr_unused--;
 }
@@ -806,6 +807,7 @@ void prune_dcache_sb(struct super_block *sb, int count)
 			spin_unlock(&dentry->d_lock);
 		} else {
 			list_move_tail(&dentry->d_lru, &tmp);
+			dentry->d_flags |= DCACHE_SHRINK_LIST;
 			spin_unlock(&dentry->d_lock);
 			if (!--count)
 				break;
@@ -1097,14 +1099,19 @@ static int select_parent(struct dentry *parent, struct list_head *dispose)
 
 		/*
 		 * move only zero ref count dentries to the dispose list.
+		 *
+		 * Those which are presently on the shrink list, being processed
+		 * by shrink_dentry_list(), shouldn't be moved.  Otherwise the
+		 * loop in shrink_dcache_parent() might not make any progress
+		 * and loop forever.
 		 */
-		if (!dentry->d_count) {
+		if (dentry->d_count) {
+			dentry_lru_del(dentry);
+		} else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
 			dentry_lru_move_list(dentry, dispose);
+			dentry->d_flags |= DCACHE_SHRINK_LIST;
 			found++;
-		} else {
-			dentry_lru_del(dentry);
 		}
-
 		/*
 		 * We can return to the caller if we have found some (this
 		 * ensures forward progress). We'll be coming back to find
diff --git a/trunk/include/linux/dcache.h b/trunk/include/linux/dcache.h
index a47bda5f76db..31f73220e7d7 100644
--- a/trunk/include/linux/dcache.h
+++ b/trunk/include/linux/dcache.h
@@ -203,6 +203,7 @@ struct dentry_operations {
 
 #define DCACHE_CANT_MOUNT	0x0100
 #define DCACHE_GENOCIDE		0x0200
+#define DCACHE_SHRINK_LIST	0x0400
 
 #define DCACHE_NFSFS_RENAMED	0x1000
      /* this dentry has been "silly renamed" and has to be deleted on the last