[PATCH] v9fs: fix fd_close

[ericvh@gmail.com (Eric Van Hensbergen)]

[PATCH] v9fs: fix fd_close

If a 9pfs server crashes, v9fs_fd_close() is called.
Subsequently, in cleaning up by performing a umount() on the FS
that was provided by this server v9fs_fd_close() is called again, and
uses the old, freed valus of trans->priv.  This patch ensures that
trans->priv can be freed only once, otherwise this function bails early.

Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

---
commit db73617a4959fa8af9f72063e3bd666c70363d99
tree 3e05d73b024cdcf7462aae64e62a63849d8aa175
parent 3603bc8dc5ab33941e6378fe52ea03b7f5561109
author Eric Van Hensbergen <ericvh@ericvh.localdomain> Thu, 29 Dec 2005 10:54:06 -0600
committer Eric Van Hensbergen <ericvh@ericvh.localdomain> Thu, 29 Dec 2005 10:54:06 -0600

 fs/9p/trans_fd.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/9p/trans_fd.c b/fs/9p/trans_fd.c
index 63b58ce..b7ffb98 100644
--- a/fs/9p/trans_fd.c
+++ b/fs/9p/trans_fd.c
@@ -148,12 +148,12 @@ static void v9fs_fd_close(struct v9fs_tr
 	if (!trans)
 		return;
 
-	trans->status = Disconnected;
-	ts = trans->priv;
+	ts = xchg(&trans->priv, NULL);
 
 	if (!ts)
 		return;
 
+	trans->status = Disconnected;
 	if (ts->in_file)
 		fput(ts->in_file);