4 files changed, 56 insertions, 4 deletions

diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index b1cc7c381e88..e9d7c2038c0f 100644
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -38,6 +38,7 @@
 #include "dlmglue.h"
 #include "file.h"
 #include "inode.h"
+#include "super.h"
 
 
 static int ocfs2_dentry_revalidate(struct dentry *dentry,
@@ -294,6 +295,34 @@ out_attach:
         return ret;
 }
 
+static DEFINE_SPINLOCK(dentry_list_lock);
+
+/* We limit the number of dentry locks to drop in one go. We have
+ * this limit so that we don't starve other users of ocfs2_wq. */
+#define DL_INODE_DROP_COUNT 64
+
+/* Drop inode references from dentry locks */
+void ocfs2_drop_dl_inodes(struct work_struct *work)
+{
+        struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
+                                               dentry_lock_work);
+        struct ocfs2_dentry_lock *dl;
+        int drop_count = DL_INODE_DROP_COUNT;
+
+        spin_lock(&dentry_list_lock);
+        while (osb->dentry_lock_list && drop_count--) {
+                dl = osb->dentry_lock_list;
+                osb->dentry_lock_list = dl->dl_next;
+                spin_unlock(&dentry_list_lock);
+                iput(dl->dl_inode);
+                kfree(dl);
+                spin_lock(&dentry_list_lock);
+        }
+        if (osb->dentry_lock_list)
+                queue_work(ocfs2_wq, &osb->dentry_lock_work);
+        spin_unlock(&dentry_list_lock);
+}
+
 /*
  * ocfs2_dentry_iput() and friends.
  *
@@ -318,16 +347,23 @@ out_attach:
 static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
                                    struct ocfs2_dentry_lock *dl)
 {
-        iput(dl->dl_inode);
         ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
         ocfs2_lock_res_free(&dl->dl_lockres);
-        kfree(dl);
+
+        /* We leave dropping of inode reference to ocfs2_wq as that can
+         * possibly lead to inode deletion which gets tricky */
+        spin_lock(&dentry_list_lock);
+        if (!osb->dentry_lock_list)
+                queue_work(ocfs2_wq, &osb->dentry_lock_work);
+        dl->dl_next = osb->dentry_lock_list;
+        osb->dentry_lock_list = dl;
+        spin_unlock(&dentry_list_lock);
 }
 
 void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
                            struct ocfs2_dentry_lock *dl)
 {
-        int unlock = 0;
+        int unlock;
 
         BUG_ON(dl->dl_count == 0);
 
diff --git a/fs/ocfs2/dcache.h b/fs/ocfs2/dcache.h
index c091c34d9883..d06e16c06640 100644
--- a/fs/ocfs2/dcache.h
+++ b/fs/ocfs2/dcache.h
@@ -29,8 +29,13 @@
 extern struct dentry_operations ocfs2_dentry_ops;
 
 struct ocfs2_dentry_lock {
+        /* Use count of dentry lock */
         unsigned int            dl_count;
-        u64                     dl_parent_blkno;
+        union {
+                /* Linked list of dentry locks to release */
+                struct ocfs2_dentry_lock *dl_next;
+                u64                     dl_parent_blkno;
+        };
 
         /*
          * The ocfs2_dentry_lock keeps an inode reference until
@@ -47,6 +52,8 @@ int ocfs2_dentry_attach_lock(struct dentry *dentry, struct inode *inode,
 void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
                            struct ocfs2_dentry_lock *dl);
 
+void ocfs2_drop_dl_inodes(struct work_struct *work);
+
 struct dentry *ocfs2_find_local_alias(struct inode *inode, u64 parent_blkno,
                                       int skip_unhashed);
 
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index ad5c24a29edd..077384135f4e 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -210,6 +210,7 @@ struct ocfs2_journal;
 struct ocfs2_slot_info;
 struct ocfs2_recovery_map;
 struct ocfs2_quota_recovery;
+struct ocfs2_dentry_lock;
 struct ocfs2_super
 {
         struct task_struct *commit_task;
@@ -325,6 +326,11 @@ struct ocfs2_super
         struct list_head blocked_lock_list;
         unsigned long blocked_lock_count;
 
+        /* List of dentry locks to release. Anyone can add locks to
+         * the list, ocfs2_wq processes the list  */
+        struct ocfs2_dentry_lock *dentry_lock_list;
+        struct work_struct dentry_lock_work;
+
         wait_queue_head_t               osb_mount_event;
 
         /* Truncate log info */
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 43ed11345b59..b1cb38fbe807 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1887,6 +1887,9 @@ static int ocfs2_initialize_super(struct super_block *sb,
         INIT_WORK(&journal->j_recovery_work, ocfs2_complete_recovery);
         journal->j_state = OCFS2_JOURNAL_FREE;
 
+        INIT_WORK(&osb->dentry_lock_work, ocfs2_drop_dl_inodes);
+        osb->dentry_lock_list = NULL;
+
         /* get some pseudo constants for clustersize bits */
         osb->s_clustersize_bits =
                 le32_to_cpu(di->id2.i_super.s_clustersize_bits);