1 files changed, 32 insertions, 2 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 6e4ea6d87774..d3902139b533 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -344,6 +344,24 @@ void d_drop(struct dentry *dentry)
 EXPORT_SYMBOL(d_drop);
 
 /*
+ * d_clear_need_lookup - drop a dentry from cache and clear the need lookup flag
+ * @dentry: dentry to drop
+ *
+ * This is called when we do a lookup on a placeholder dentry that needed to be
+ * looked up.  The dentry should have been hashed in order for it to be found by
+ * the lookup code, but now needs to be unhashed while we do the actual lookup
+ * and clear the DCACHE_NEED_LOOKUP flag.
+ */
+void d_clear_need_lookup(struct dentry *dentry)
+{
+        spin_lock(&dentry->d_lock);
+        __d_drop(dentry);
+        dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
+        spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL(d_clear_need_lookup);
+
+/*
  * Finish off a dentry we've decided to kill.
  * dentry->d_lock must be held, returns with it unlocked.
  * If ref is non-zero, then decrement the refcount too.
@@ -432,8 +450,13 @@ repeat:
         if (d_unhashed(dentry))
                 goto kill_it;
 
-        /* Otherwise leave it cached and ensure it's on the LRU */
-        dentry->d_flags |= DCACHE_REFERENCED;
+        /*
+         * If this dentry needs lookup, don't set the referenced flag so that it
+         * is more likely to be cleaned up by the dcache shrinker in case of
+         * memory pressure.
+         */
+        if (!d_need_lookup(dentry))
+                dentry->d_flags |= DCACHE_REFERENCED;
         dentry_lru_add(dentry);
 
         dentry->d_count--;
@@ -1708,6 +1731,13 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
         }
 
         /*
+         * We are going to instantiate this dentry, unhash it and clear the
+         * lookup flag so we can do that.
+         */
+        if (unlikely(d_need_lookup(found)))
+                d_clear_need_lookup(found);
+
+        /*
          * Negative dentry: instantiate it unless the inode is a directory and
          * already has a dentry.
          */