Merge tag 'for-linus-merge-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

Pull v9fs update from Eric Van Hensbergen.

* tag 'for-linus-merge-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9P: Fix race between p9_write_work() and p9_fd_request()
  9P: Fix race in p9_write_work()
  9P: fix test at the end of p9_write_work()
  9P: Fix race in p9_read_work()
  9p: don't use __getname/__putname for uname/aname
  net/9p: Check errno validity
  fs/9p: avoid debug OOPS when reading a long symlink

2 files changed, 36 insertions, 20 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 8260f13..34d4176 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -76,6 +76,20 @@ inline int p9_is_proto_dotu(struct p9_client *clnt)
 }
 EXPORT_SYMBOL(p9_is_proto_dotu);
 
+/*
+ * Some error codes are taken directly from the server replies,
+ * make sure they are valid.
+ */
+static int safe_errno(int err)
+{
+	if ((err > 0) || (err < -MAX_ERRNO)) {
+		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
+		return -EPROTO;
+	}
+	return err;
+}
+
+
 /* Interpret mount option for protocol version */
 static int get_protocol_version(char *s)
 {
@@ -782,7 +796,7 @@ again:
 		return req;
 reterr:
 	p9_free_req(c, req);
-	return ERR_PTR(err);
+	return ERR_PTR(safe_errno(err));
 }
 
 /**
@@ -865,7 +879,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
 		return req;
 reterr:
 	p9_free_req(c, req);
-	return ERR_PTR(err);
+	return ERR_PTR(safe_errno(err));
 }
 
 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 15656b8..02efb25 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -316,8 +316,7 @@ static void p9_read_work(struct work_struct *work)
 						m->rsize - m->rpos);
 	p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err);
 	if (err == -EAGAIN) {
-		clear_bit(Rworksched, &m->wsched);
-		return;
+		goto end_clear;
 	}
 
 	if (err <= 0)
@@ -379,19 +378,20 @@ static void p9_read_work(struct work_struct *work)
 		m->req = NULL;
 	}
 
+end_clear:
+	clear_bit(Rworksched, &m->wsched);
+
 	if (!list_empty(&m->req_list)) {
 		if (test_and_clear_bit(Rpending, &m->wsched))
 			n = POLLIN;
 		else
 			n = p9_fd_poll(m->client, NULL);
 
-		if (n & POLLIN) {
+		if ((n & POLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) {
 			p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
 			schedule_work(&m->rq);
-		} else
-			clear_bit(Rworksched, &m->wsched);
-	} else
-		clear_bit(Rworksched, &m->wsched);
+		}
+	}
 
 	return;
 error:
@@ -453,12 +453,13 @@ static void p9_write_work(struct work_struct *work)
 	}
 
 	if (!m->wsize) {
+		spin_lock(&m->client->lock);
 		if (list_empty(&m->unsent_req_list)) {
 			clear_bit(Wworksched, &m->wsched);
+			spin_unlock(&m->client->lock);
 			return;
 		}
 
-		spin_lock(&m->client->lock);
 		req = list_entry(m->unsent_req_list.next, struct p9_req_t,
 			       req_list);
 		req->status = REQ_STATUS_SENT;
@@ -476,10 +477,9 @@ static void p9_write_work(struct work_struct *work)
 	clear_bit(Wpending, &m->wsched);
 	err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
 	p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err);
-	if (err == -EAGAIN) {
-		clear_bit(Wworksched, &m->wsched);
-		return;
-	}
+	if (err == -EAGAIN)
+		goto end_clear;
+
 
 	if (err < 0)
 		goto error;
@@ -492,19 +492,21 @@ static void p9_write_work(struct work_struct *work)
 	if (m->wpos == m->wsize)
 		m->wpos = m->wsize = 0;
 
-	if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
+end_clear:
+	clear_bit(Wworksched, &m->wsched);
+
+	if (m->wsize || !list_empty(&m->unsent_req_list)) {
 		if (test_and_clear_bit(Wpending, &m->wsched))
 			n = POLLOUT;
 		else
 			n = p9_fd_poll(m->client, NULL);
 
-		if (n & POLLOUT) {
+		if ((n & POLLOUT) &&
+		   !test_and_set_bit(Wworksched, &m->wsched)) {
 			p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
 			schedule_work(&m->wq);
-		} else
-			clear_bit(Wworksched, &m->wsched);
-	} else
-		clear_bit(Wworksched, &m->wsched);
+		}
+	}
 
 	return;