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Commit ad6b1340 authored by Stanislav Kinsbursky's avatar Stanislav Kinsbursky Committed by Trond Myklebust
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SUNRPC: fix pipe->ops cleanup on pipe dentry unlink 



This patch looks late due to GSS AUTH patches sent already. But it fixes a flaw
in RPC PipeFS pipes handling.
I've added this patch in the series, because this series related to pipes. But
it should be a part of previous series named "SUNPRC: cleanup PipeFS for
network-namespace-aware users".

Pipe dentry can be created and destroyed many times during pipe life cycle.
This actually means, that we can't set pipe->ops to NULL in rpc_close_pipes()
and use this variable as a flag, indicating, that pipe's dentry is unlinking.
To follow this restriction, this patch replaces "pipe->ops = NULL" assignment
and checks for NULL with "pipe->dentry = NULL" assignment and checks for
NULL respectively.
This patch also removes check for non-NULL pipe->ops (or pipe->dentry) in
rpc_close_pipes() because it always non-NULL now.

Signed-off-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 39cb67b9

net/sunrpc/rpc_pipe.c

+20 −31
Original line number Diff line number Diff line
@@ -86,10 +86,6 @@ rpc_timeout_upcall_queue(struct work_struct *work) 
	void (*destroy_msg)(struct rpc_pipe_msg *);



	spin_lock(&pipe->lock);

	if (pipe->ops == NULL) {

		spin_unlock(&pipe->lock);

		return;

	}

	destroy_msg = pipe->ops->destroy_msg;

	if (pipe->nreaders == 0) {

		list_splice_init(&pipe->pipe, &free_list);
@@ -135,8 +131,6 @@ rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg) 
	int res = -EPIPE;



	spin_lock(&pipe->lock);

	if (pipe->ops == NULL)

		goto out;

	if (pipe->nreaders) {

		list_add_tail(&msg->list, &pipe->pipe);

		pipe->pipelen += msg->len;
@@ -150,7 +144,6 @@ rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg) 
		pipe->pipelen += msg->len;

		res = 0;

	}

out:

	spin_unlock(&pipe->lock);

	wake_up(&pipe->waitq);

	return res;
@@ -167,27 +160,23 @@ static void 
rpc_close_pipes(struct inode *inode)

{

	struct rpc_pipe *pipe = RPC_I(inode)->pipe;

	const struct rpc_pipe_ops *ops;

	int need_release;

	LIST_HEAD(free_list);



	mutex_lock(&inode->i_mutex);

	ops = pipe->ops;

	if (ops != NULL) {

		LIST_HEAD(free_list);

	spin_lock(&pipe->lock);

	need_release = pipe->nreaders != 0 || pipe->nwriters != 0;

	pipe->nreaders = 0;

	list_splice_init(&pipe->in_upcall, &free_list);

	list_splice_init(&pipe->pipe, &free_list);

	pipe->pipelen = 0;

		pipe->ops = NULL;

	pipe->dentry = NULL;

	spin_unlock(&pipe->lock);

		rpc_purge_list(pipe, &free_list, ops->destroy_msg, -EPIPE);

	rpc_purge_list(pipe, &free_list, pipe->ops->destroy_msg, -EPIPE);

	pipe->nwriters = 0;

		if (need_release && ops->release_pipe)

			ops->release_pipe(inode);

	if (need_release && pipe->ops->release_pipe)

		pipe->ops->release_pipe(inode);

	cancel_delayed_work_sync(&pipe->queue_timeout);

	}

	rpc_inode_setowner(inode, NULL);

	mutex_unlock(&inode->i_mutex);

}
@@ -223,7 +212,7 @@ rpc_pipe_open(struct inode *inode, struct file *filp) 
	int res = -ENXIO;



	mutex_lock(&inode->i_mutex);

	if (pipe->ops == NULL)

	if (pipe->dentry == NULL)

		goto out;

	first_open = pipe->nreaders == 0 && pipe->nwriters == 0;

	if (first_open && pipe->ops->open_pipe) {
@@ -249,7 +238,7 @@ rpc_pipe_release(struct inode *inode, struct file *filp) 
	int last_close;



	mutex_lock(&inode->i_mutex);

	if (pipe->ops == NULL)

	if (pipe->dentry == NULL)

		goto out;

	msg = filp->private_data;

	if (msg != NULL) {
@@ -290,7 +279,7 @@ rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset) 
	int res = 0;



	mutex_lock(&inode->i_mutex);

	if (pipe->ops == NULL) {

	if (pipe->dentry == NULL) {

		res = -EPIPE;

		goto out_unlock;

	}
@@ -333,7 +322,7 @@ rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *of 


	mutex_lock(&inode->i_mutex);

	res = -EPIPE;

	if (pipe->ops != NULL)

	if (pipe->dentry != NULL)

		res = pipe->ops->downcall(filp, buf, len);

	mutex_unlock(&inode->i_mutex);

	return res;
@@ -348,7 +337,7 @@ rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait) 
	poll_wait(filp, &pipe->waitq, wait);



	mask = POLLOUT | POLLWRNORM;

	if (pipe->ops == NULL)

	if (pipe->dentry == NULL)

		mask |= POLLERR | POLLHUP;

	if (filp->private_data || !list_empty(&pipe->pipe))

		mask |= POLLIN | POLLRDNORM;
@@ -365,7 +354,7 @@ rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
	switch (cmd) {

	case FIONREAD:

		spin_lock(&pipe->lock);

		if (pipe->ops == NULL) {

		if (pipe->dentry == NULL) {

			spin_unlock(&pipe->lock);

			return -EPIPE;

		}