From 034b91a3b66cf9d2983ac45f73162395c0936c36 Mon Sep 17 00:00:00 2001
From: Latchesar Ionkov <lucho@ionkov.net>
Date: Fri, 3 Feb 2006 03:04:20 -0800
Subject: [PATCH] [PATCH] v9fs: fix corner cases when flushing request
When v9fs_mux_rpc sends a 9P message, it may be put in the queue of unsent
request. If the user process receives a signal, v9fs_mux_rpc sets the
request error to ERREQFLUSH and assigns NULL to request's send message. If
the message was still in the unsent queue, v9fs_write_work would produce an
oops while processing it.
The patch makes sure that requests that are being flushed are moved to the
pending requests queue safely.
If a request is being flushed, don't remove it from the list of pending
requests even if it receives a reply before the flush is acknoledged. The
request will be removed during from the Rflush handler (v9fs_mux_flush_cb).
Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Cc: Eric Van Hensbergen <ericvh@ericvh.myip.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
fs/9p/mux.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/fs/9p/mux.c b/fs/9p/mux.c
index 945cb368d451..ea1134eb47c8 100644
--- a/fs/9p/mux.c
+++ b/fs/9p/mux.c
@@ -471,10 +471,13 @@ static void v9fs_write_work(void *a)
}
spin_lock(&m->lock);
- req =
- list_entry(m->unsent_req_list.next, struct v9fs_req,
+again:
+ req = list_entry(m->unsent_req_list.next, struct v9fs_req,
req_list);
list_move_tail(&req->req_list, &m->req_list);
+ if (req->err == ERREQFLUSH)
+ goto again;
+
m->wbuf = req->tcall->sdata;
m->wsize = req->tcall->size;
m->wpos = 0;
@@ -525,7 +528,7 @@ static void process_request(struct v9fs_mux_data *m, struct v9fs_req *req)
struct v9fs_str *ename;
tag = req->tag;
- if (req->rcall->id == RERROR && !req->err) {
+ if (!req->err && req->rcall->id == RERROR) {
ecode = req->rcall->params.rerror.errno;
ename = &req->rcall->params.rerror.error;
@@ -551,7 +554,10 @@ static void process_request(struct v9fs_mux_data *m, struct v9fs_req *req)
req->err = -EIO;
}
- if (req->cb && req->err != ERREQFLUSH) {
+ if (req->err == ERREQFLUSH)
+ return;
+
+ if (req->cb) {
dprintk(DEBUG_MUX, "calling callback tcall %p rcall %p\n",
req->tcall, req->rcall);
@@ -812,6 +818,7 @@ v9fs_mux_rpc_cb(void *a, struct v9fs_fcall *tc, struct v9fs_fcall *rc, int err)
struct v9fs_mux_rpc *r;
if (err == ERREQFLUSH) {
+ kfree(rc);
dprintk(DEBUG_MUX, "err req flush\n");
return;
}