1 files changed, 40 insertions, 5 deletions

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index c65b748688ff..6b5ddd5492bc 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -90,6 +90,23 @@ find_disconnected_root(struct dentry *dentry)
         return dentry;
 }
 
+static bool dentry_connected(struct dentry *dentry)
+{
+        dget(dentry);
+        while (dentry->d_flags & DCACHE_DISCONNECTED) {
+                struct dentry *parent = dget_parent(dentry);
+
+                dput(dentry);
+                if (IS_ROOT(dentry)) {
+                        dput(parent);
+                        return false;
+                }
+                dentry = parent;
+        }
+        dput(dentry);
+        return true;
+}
+
 static void clear_disconnected(struct dentry *dentry)
 {
         dget(dentry);
@@ -189,9 +206,9 @@ reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
                                 dput(pd);
                                 if (err == -ENOENT)
                                         /* some race between get_parent and
-                                         * get_name?  just try again
+                                         * get_name?
                                          */
-                                        continue;
+                                        goto out_reconnected;
                                 break;
                         }
                         dprintk("%s: found name: %s\n", __func__, nbuf);
@@ -211,12 +228,12 @@ reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
                          * hopefully, npd == pd, though it isn't really
                          * a problem if it isn't
                          */
+                        dput(npd);
+                        dput(ppd);
                         if (npd == pd)
                                 noprogress = 0;
                         else
-                                printk("%s: npd != pd\n", __func__);
-                        dput(npd);
-                        dput(ppd);
+                                goto out_reconnected;
                         if (IS_ROOT(pd)) {
                                 /* something went wrong, we have to give up */
                                 dput(pd);
@@ -234,6 +251,24 @@ reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
         }
 
         return 0;
+out_reconnected:
+        /*
+         * Someone must have renamed our entry into another parent, in
+         * which case it has been reconnected by the rename.
+         *
+         * Or someone removed it entirely, in which case filehandle
+         * lookup will succeed but the directory is now IS_DEAD and
+         * subsequent operations on it will fail.
+         *
+         * Alternatively, maybe there was no race at all, and the
+         * filesystem is just corrupt and gave us a parent that doesn't
+         * actually contain any entry pointing to this inode.  So,
+         * double check that this worked and return -ESTALE if not:
+         */
+        if (!dentry_connected(target_dir))
+                return -ESTALE;
+        clear_disconnected(target_dir);
+        return 0;
 }
 
 struct getdents_callback {