SUNRPC: Clean up the sillyrename code

Fix a couple of bugs:
 - Don't rely on the parent dentry still being valid when the call completes.
   Fixes a race with shrink_dcache_for_umount_subtree()

 - Don't remove the file if the filehandle has been labelled as stale.

Fix a couple of inefficiencies
 - Remove the global list of sillyrenamed files. Instead we can cache the
   sillyrename information in the dentry->d_fsdata
 - Move common code from unlink_setup/unlink_done into fs/nfs/unlink.c

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 86 insertions, 109 deletions

diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 0e28189c2151..045ab805c17f 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -3,7 +3,6 @@
  *
  * nfs sillydelete handling
  *
- * NOTE: we rely on holding the BKL for list manipulation protection.
  */
 
 #include <linux/slab.h>
@@ -15,46 +14,23 @@
 
 
 struct nfs_unlinkdata {
-	struct nfs_unlinkdata	*next;
-	struct dentry	*dir, *dentry;
-	struct qstr	name;
-	struct rpc_task	task;
+	struct nfs_removeargs args;
+	struct nfs_removeres res;
+	struct inode *dir;
 	struct rpc_cred	*cred;
-	unsigned int	count;
 };
 
-static struct nfs_unlinkdata	*nfs_deletes;
-static RPC_WAITQ(nfs_delete_queue, "nfs_delete_queue");
-
-/**
- * nfs_detach_unlinkdata - Remove asynchronous unlink from global list
- * @data: pointer to descriptor
- */
-static inline void
-nfs_detach_unlinkdata(struct nfs_unlinkdata *data)
-{
-	struct nfs_unlinkdata	**q;
-
-	for (q = &nfs_deletes; *q != NULL; q = &((*q)->next)) {
-		if (*q == data) {
-			*q = data->next;
-			break;
-		}
-	}
-}
-
 /**
- * nfs_put_unlinkdata - release data from a sillydelete operation.
+ * nfs_free_unlinkdata - release data from a sillydelete operation.
  * @data: pointer to unlink structure.
  */
 static void
-nfs_put_unlinkdata(struct nfs_unlinkdata *data)
+nfs_free_unlinkdata(struct nfs_unlinkdata *data)
 {
-	if (--data->count == 0) {
-		nfs_detach_unlinkdata(data);
-		kfree(data->name.name);
-		kfree(data);
-	}
+	iput(data->dir);
+	put_rpccred(data->cred);
+	kfree(data->args.name.name);
+	kfree(data);
 }
 
 #define NAME_ALLOC_LEN(len)	((len+16) & ~15)
@@ -63,50 +39,36 @@ nfs_put_unlinkdata(struct nfs_unlinkdata *data)
  * @dentry: pointer to dentry
  * @data: nfs_unlinkdata
  */
-static inline void
-nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
+static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
 {
 	char		*str;
 	int		len = dentry->d_name.len;
 
-	str = kmalloc(NAME_ALLOC_LEN(len), GFP_KERNEL);
+	str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
 	if (!str)
-		return;
-	memcpy(str, dentry->d_name.name, len);
-	if (!data->name.len) {
-		data->name.len = len;
-		data->name.name = str;
-	} else
-		kfree(str);
+		return -ENOMEM;
+	data->args.name.len = len;
+	data->args.name.name = str;
+	return 0;
 }
 
 /**
  * nfs_async_unlink_init - Initialize the RPC info
- * @task: rpc_task of the sillydelete
- *
- * We delay initializing RPC info until after the call to dentry_iput()
- * in order to minimize races against rename().
+ * task: rpc_task of the sillydelete
  */
 static void nfs_async_unlink_init(struct rpc_task *task, void *calldata)
 {
-	struct nfs_unlinkdata	*data = calldata;
-	struct dentry		*dir = data->dir;
-	struct rpc_message	msg = {
-		.rpc_cred	= data->cred,
+	struct nfs_unlinkdata *data = calldata;
+	struct inode *dir = data->dir;
+	struct rpc_message msg = {
+		.rpc_argp = &data->args,
+		.rpc_resp = &data->res,
+		.rpc_cred = data->cred,
 	};
-	int			status = -ENOENT;
-
-	if (!data->name.len)
-		goto out_err;
 
-	status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);
-	if (status < 0)
-		goto out_err;
-	nfs_begin_data_update(dir->d_inode);
+	nfs_begin_data_update(dir);
+	NFS_PROTO(dir)->unlink_setup(&msg, dir);
 	rpc_call_setup(task, &msg, 0);
-	return;
- out_err:
-	rpc_exit(task, status);
 }
 
 /**
@@ -117,19 +79,13 @@ static void nfs_async_unlink_init(struct rpc_task *task, void *calldata)
  */
 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
 {
-	struct nfs_unlinkdata	*data = calldata;
-	struct dentry		*dir = data->dir;
-	struct inode		*dir_i;
-
-	if (!dir)
-		return;
-	dir_i = dir->d_inode;
-	nfs_end_data_update(dir_i);
-	if (NFS_PROTO(dir_i)->unlink_done(dir, task))
-		return;
-	put_rpccred(data->cred);
-	data->cred = NULL;
-	dput(dir);
+	struct nfs_unlinkdata *data = calldata;
+	struct inode *dir = data->dir;
+
+	if (!NFS_PROTO(dir)->unlink_done(task, dir))
+		rpc_restart_call(task);
+	else
+		nfs_end_data_update(dir);
 }
 
 /**
@@ -142,7 +98,7 @@ static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
 static void nfs_async_unlink_release(void *calldata)
 {
 	struct nfs_unlinkdata	*data = calldata;
-	nfs_put_unlinkdata(data);
+	nfs_free_unlinkdata(data);
 }
 
 static const struct rpc_call_ops nfs_unlink_ops = {
@@ -151,73 +107,94 @@ static const struct rpc_call_ops nfs_unlink_ops = {
 	.rpc_release = nfs_async_unlink_release,
 };
 
+static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
+{
+	struct rpc_task *task;
+	struct dentry *parent;
+	struct inode *dir;
+
+	if (nfs_copy_dname(dentry, data) < 0)
+		goto out_free;
+
+	parent = dget_parent(dentry);
+	if (parent == NULL)
+		goto out_free;
+	dir = igrab(parent->d_inode);
+	dput(parent);
+	if (dir == NULL)
+		goto out_free;
+
+	data->dir = dir;
+	data->args.fh = NFS_FH(dir);
+	nfs_fattr_init(&data->res.dir_attr);
+
+	task = rpc_run_task(NFS_CLIENT(dir), RPC_TASK_ASYNC, &nfs_unlink_ops, data);
+	if (!IS_ERR(task))
+		rpc_put_task(task);
+	return 1;
+out_free:
+	return 0;
+}
+
 /**
  * nfs_async_unlink - asynchronous unlinking of a file
+ * @dir: parent directory of dentry
  * @dentry: dentry to unlink
  */
 int
-nfs_async_unlink(struct dentry *dentry)
+nfs_async_unlink(struct inode *dir, struct dentry *dentry)
 {
-	struct dentry	*dir = dentry->d_parent;
-	struct nfs_unlinkdata	*data;
-	struct rpc_clnt	*clnt = NFS_CLIENT(dir->d_inode);
-	int		status = -ENOMEM;
+	struct nfs_unlinkdata *data;
+	int status = -ENOMEM;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (!data)
+	if (data == NULL)
 		goto out;
 
-	data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);
+	data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
 	if (IS_ERR(data->cred)) {
 		status = PTR_ERR(data->cred);
 		goto out_free;
 	}
-	data->dir = dget(dir);
-	data->dentry = dentry;
-
-	data->next = nfs_deletes;
-	nfs_deletes = data;
-	data->count = 1;
-
-	rpc_init_task(&data->task, clnt, RPC_TASK_ASYNC, &nfs_unlink_ops, data);
 
+	status = -EBUSY;
 	spin_lock(&dentry->d_lock);
+	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+		goto out_unlock;
 	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+	dentry->d_fsdata = data;
 	spin_unlock(&dentry->d_lock);
-
-	rpc_sleep_on(&nfs_delete_queue, &data->task, NULL, NULL);
-	status = 0;
- out:
-	return status;
+	return 0;
+out_unlock:
+	spin_unlock(&dentry->d_lock);
+	put_rpccred(data->cred);
 out_free:
 	kfree(data);
+out:
 	return status;
 }
 
 /**
  * nfs_complete_unlink - Initialize completion of the sillydelete
  * @dentry: dentry to delete
+ * @inode: inode
  *
  * Since we're most likely to be called by dentry_iput(), we
  * only use the dentry to find the sillydelete. We then copy the name
  * into the qstr.
  */
 void
-nfs_complete_unlink(struct dentry *dentry)
+nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
 {
-	struct nfs_unlinkdata	*data;
+	struct nfs_unlinkdata	*data = NULL;
 
-	for(data = nfs_deletes; data != NULL; data = data->next) {
-		if (dentry == data->dentry)
-			break;
-	}
-	if (!data)
-		return;
-	data->count++;
-	nfs_copy_dname(dentry, data);
 	spin_lock(&dentry->d_lock);
-	dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+		dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
+		data = dentry->d_fsdata;
+	}
 	spin_unlock(&dentry->d_lock);
-	rpc_wake_up_task(&data->task);
-	nfs_put_unlinkdata(data);
+
+	if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
+		nfs_free_unlinkdata(data);
 }