[PATCH] ocfs2: fix orphan recovery deadlock

Orphan dir recovery can deadlock with another process in
ocfs2_delete_inode() in some corner cases. Fix this by tracking recovery
state more closely and allowing it to handle inode wipes which might
deadlock.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 45 insertions, 1 deletions

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 8122489c576..315472a5c19 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -41,6 +41,7 @@
 #include "dlmglue.h"
 #include "extent_map.h"
 #include "file.h"
+#include "heartbeat.h"
 #include "inode.h"
 #include "journal.h"
 #include "namei.h"
@@ -544,6 +545,42 @@ bail:
         return status;
 }
 
+/* 
+ * Serialize with orphan dir recovery. If the process doing
+ * recovery on this orphan dir does an iget() with the dir
+ * i_mutex held, we'll deadlock here. Instead we detect this
+ * and exit early - recovery will wipe this inode for us.
+ */
+static int ocfs2_check_orphan_recovery_state(struct ocfs2_super *osb,
+                                             int slot)
+{
+        int ret = 0;
+
+        spin_lock(&osb->osb_lock);
+        if (ocfs2_node_map_test_bit(osb, &osb->osb_recovering_orphan_dirs, slot)) {
+                mlog(0, "Recovery is happening on orphan dir %d, will skip "
+                     "this inode\n", slot);
+                ret = -EDEADLK;
+                goto out;
+        }
+        /* This signals to the orphan recovery process that it should
+         * wait for us to handle the wipe. */
+        osb->osb_orphan_wipes[slot]++;
+out:
+        spin_unlock(&osb->osb_lock);
+        return ret;
+}
+
+static void ocfs2_signal_wipe_completion(struct ocfs2_super *osb,
+                                         int slot)
+{
+        spin_lock(&osb->osb_lock);
+        osb->osb_orphan_wipes[slot]--;
+        spin_unlock(&osb->osb_lock);
+
+        wake_up(&osb->osb_wipe_event);
+}
+
 static int ocfs2_wipe_inode(struct inode *inode,
                             struct buffer_head *di_bh)
 {
@@ -555,6 +592,11 @@ static int ocfs2_wipe_inode(struct inode *inode,
         /* We've already voted on this so it should be readonly - no
          * spinlock needed. */
         orphaned_slot = OCFS2_I(inode)->ip_orphaned_slot;
+
+        status = ocfs2_check_orphan_recovery_state(osb, orphaned_slot);
+        if (status)
+                return status;
+
         orphan_dir_inode = ocfs2_get_system_file_inode(osb,
                                                        ORPHAN_DIR_SYSTEM_INODE,
                                                        orphaned_slot);
@@ -597,6 +639,7 @@ bail_unlock_dir:
         brelse(orphan_dir_bh);
 bail:
         iput(orphan_dir_inode);
+        ocfs2_signal_wipe_completion(osb, orphaned_slot);
 
         return status;
 }
@@ -822,7 +865,8 @@ void ocfs2_delete_inode(struct inode *inode)
 
         status = ocfs2_wipe_inode(inode, di_bh);
         if (status < 0) {
-                mlog_errno(status);
+                if (status != -EDEADLK)
+                        mlog_errno(status);
                 goto bail_unlock_inode;
         }