7 files changed, 46 insertions, 10 deletions

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 7413d065906b..1b8490e2fbde 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -324,7 +324,7 @@ static int handle_remove(const char *nodename, struct device *dev)
                         mutex_lock(&dentry->d_inode->i_mutex);
                         notify_change(dentry, &newattrs);
                         mutex_unlock(&dentry->d_inode->i_mutex);
-                        err = vfs_unlink(parent.dentry->d_inode, dentry);
+                        err = vfs_unlink(parent.dentry->d_inode, dentry, NULL);
                         if (!err || err == -ENOENT)
                                 deleted = 1;
                 }
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index f4a08d7fa2f7..31d480c0e046 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -294,7 +294,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache,
                 if (ret < 0) {
                         cachefiles_io_error(cache, "Unlink security error");
                 } else {
-                        ret = vfs_unlink(dir->d_inode, rep);
+                        ret = vfs_unlink(dir->d_inode, rep, NULL);
 
                         if (preemptive)
                                 cachefiles_mark_object_buried(cache, rep);
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 0f9b66eaa767..dc60b8bd09ec 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -153,7 +153,7 @@ static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 
         dget(lower_dentry);
         lower_dir_dentry = lock_parent(lower_dentry);
-        rc = vfs_unlink(lower_dir_inode, lower_dentry);
+        rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
         if (rc) {
                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
                 goto out_unlock;
@@ -208,7 +208,7 @@ ecryptfs_do_create(struct inode *directory_inode,
         inode = __ecryptfs_get_inode(lower_dentry->d_inode,
                                      directory_inode->i_sb);
         if (IS_ERR(inode)) {
-                vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
+                vfs_unlink(lower_dir_dentry->d_inode, lower_dentry, NULL);
                 goto out_lock;
         }
         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
diff --git a/fs/namei.c b/fs/namei.c
index e633a58d4222..67ce331a3ed8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3615,7 +3615,25 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
         return do_rmdir(AT_FDCWD, pathname);
 }
 
-int vfs_unlink(struct inode *dir, struct dentry *dentry)
+/**
+ * vfs_unlink - unlink a filesystem object
+ * @dir:        parent directory
+ * @dentry:     victim
+ * @delegated_inode: returns victim inode, if the inode is delegated.
+ *
+ * The caller must hold dir->i_mutex.
+ *
+ * If vfs_unlink discovers a delegation, it will return -EWOULDBLOCK and
+ * return a reference to the inode in delegated_inode.  The caller
+ * should then break the delegation on that inode and retry.  Because
+ * breaking a delegation may take a long time, the caller should drop
+ * dir->i_mutex before doing so.
+ *
+ * Alternatively, a caller may pass NULL for delegated_inode.  This may
+ * be appropriate for callers that expect the underlying filesystem not
+ * to be NFS exported.
+ */
+int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
 {
         struct inode *target = dentry->d_inode;
         int error = may_delete(dir, dentry, 0);
@@ -3632,11 +3650,20 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
         else {
                 error = security_inode_unlink(dir, dentry);
                 if (!error) {
+                        error = break_deleg(target, O_WRONLY|O_NONBLOCK);
+                        if (error) {
+                                if (error == -EWOULDBLOCK && delegated_inode) {
+                                        *delegated_inode = target;
+                                        ihold(target);
+                                }
+                                goto out;
+                        }
                         error = dir->i_op->unlink(dir, dentry);
                         if (!error)
                                 dont_mount(dentry);
                 }
         }
+out:
         mutex_unlock(&target->i_mutex);
 
         /* We don't d_delete() NFS sillyrenamed files--they still exist. */
@@ -3661,6 +3688,7 @@ static long do_unlinkat(int dfd, const char __user *pathname)
         struct dentry *dentry;
         struct nameidata nd;
         struct inode *inode = NULL;
+        struct inode *delegated_inode = NULL;
         unsigned int lookup_flags = 0;
 retry:
         name = user_path_parent(dfd, pathname, &nd, lookup_flags);
@@ -3675,7 +3703,7 @@ retry:
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto exit1;
-
+retry_deleg:
         mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
         dentry = lookup_hash(&nd);
         error = PTR_ERR(dentry);
@@ -3690,13 +3718,21 @@ retry:
                 error = security_path_unlink(&nd.path, dentry);
                 if (error)
                         goto exit2;
-                error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+                error = vfs_unlink(nd.path.dentry->d_inode, dentry, &delegated_inode);
 exit2:
                 dput(dentry);
         }
         mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
         if (inode)
                 iput(inode);    /* truncate the inode here */
+        inode = NULL;
+        if (delegated_inode) {
+                error = break_deleg(delegated_inode, O_WRONLY);
+                iput(delegated_inode);
+                delegated_inode = NULL;
+                if (!error)
+                        goto retry_deleg;
+        }
         mnt_drop_write(nd.path.mnt);
 exit1:
         path_put(&nd.path);
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 13886f7f40d5..7a810235d599 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1910,7 +1910,7 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
         if (host_err)
                 goto out_put;
         if (type != S_IFDIR)
-                host_err = vfs_unlink(dirp, rdentry);
+                host_err = vfs_unlink(dirp, rdentry, NULL);
         else
                 host_err = vfs_rmdir(dirp, rdentry);
         if (!host_err)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8e4be1be1a62..a5799233142a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1455,7 +1455,7 @@ extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
 extern int vfs_rmdir(struct inode *, struct dentry *);
-extern int vfs_unlink(struct inode *, struct dentry *);
+extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 
 /*
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index ae1996d3c539..95827ce2f3c7 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -886,7 +886,7 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
                 err = -ENOENT;
         } else {
                 ihold(inode);
-                err = vfs_unlink(dentry->d_parent->d_inode, dentry);
+                err = vfs_unlink(dentry->d_parent->d_inode, dentry, NULL);
         }
         dput(dentry);