From: Marc Dionne <marc.c.dionne@gmail.com>
Date: Thu, 6 Sep 2012 00:25:55 +0000 (-0400)
Subject: Linux: drop GLOCK before calling dput
X-Git-Tag: openafs-stable-1_8_0pre1~2040
X-Git-Url: http://git.openafs.org/?p=openafs.git;a=commitdiff_plain;h=0dac4de8eee84a43ef06c56dfc867c2a1b9a9f0c;hp=777e03103f5eb05012ea1f7f23624515e4ed6bb4

Linux: drop GLOCK before calling dput

Holding the GLOCK when calling dput can result in a deadlock when
the kernel calls back into afs_dentry_iput.  It should be safe
to drop the lock here.

Change-Id: I8966aea7336b39b4c3ec265a53d820fc6135eeaf
Reviewed-on: http://gerrit.openafs.org/8046
Reviewed-by: Simon Wilkinson <simonxwilkinson@gmail.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: Derrick Brashear <shadow@your-file-system.com>
---

diff --git a/src/afs/afs_pioctl.c b/src/afs/afs_pioctl.c
index aab52ff..0836b87 100644
--- a/src/afs/afs_pioctl.c
+++ b/src/afs/afs_pioctl.c
@@ -1239,7 +1239,13 @@ afs_syscall_pioctl(char *path, unsigned int com, caddr_t cmarg, int follow)
 #endif /* AFS_NEED_CLIENTCONTEXT */
     if (vp) {
 #ifdef AFS_LINUX22_ENV
+	/*
+	 * Holding the global lock when calling dput can cause a deadlock
+	 * when the kernel calls back into afs_dentry_iput
+	 */
+	AFS_GUNLOCK();
 	dput(dp);
+	AFS_GLOCK();
 #else
 #if defined(AFS_FBSD80_ENV)
     if (VOP_ISLOCKED(vp))