Module Name: src
Committed By: hannken
Date: Sat Jan 4 12:36:49 UTC 2014
Modified Files:
src/sys/fs/tmpfs: tmpfs_vfsops.c
Log Message:
Fix a race where thread1 runs VOP_REMOVE() and gets preempted in
tmpfs_reclaim() before the call to tmpfs_free_node(). Thread2
runs VFS_FHTOVP() and gets a new vnode attached to the node thread1
is about to destroy.
Change tmpfs_fhtovp() to check the generation number after
tmpfs_vnode_get() succeeded.
To generate a diff of this commit:
cvs rdiff -u -r1.55 -r1.56 src/sys/fs/tmpfs/tmpfs_vfsops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/fs/tmpfs/tmpfs_vfsops.c
diff -u src/sys/fs/tmpfs/tmpfs_vfsops.c:1.55 src/sys/fs/tmpfs/tmpfs_vfsops.c:1.56
--- src/sys/fs/tmpfs/tmpfs_vfsops.c:1.55 Sat Nov 23 16:35:32 2013
+++ src/sys/fs/tmpfs/tmpfs_vfsops.c Sat Jan 4 12:36:49 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: tmpfs_vfsops.c,v 1.55 2013/11/23 16:35:32 rmind Exp $ */
+/* $NetBSD: tmpfs_vfsops.c,v 1.56 2014/01/04 12:36:49 hannken Exp $ */
/*
* Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -42,7 +42,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.55 2013/11/23 16:35:32 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.56 2014/01/04 12:36:49 hannken Exp $");
#include <sys/param.h>
#include <sys/types.h>
@@ -282,6 +282,7 @@ tmpfs_fhtovp(struct mount *mp, struct fi
tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp);
tmpfs_node_t *node;
tmpfs_fid_t tfh;
+ int error;
if (fhp->fid_len != sizeof(tmpfs_fid_t)) {
return EINVAL;
@@ -290,19 +291,25 @@ tmpfs_fhtovp(struct mount *mp, struct fi
mutex_enter(&tmp->tm_lock);
LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
- if (node->tn_id != tfh.tf_id) {
- continue;
- }
- if (TMPFS_NODE_GEN(node) != tfh.tf_gen) {
- continue;
+ if (node->tn_id == tfh.tf_id) {
+ mutex_enter(&node->tn_vlock);
+ break;
}
- mutex_enter(&node->tn_vlock);
- break;
}
mutex_exit(&tmp->tm_lock);
+ if (node == NULL)
+ return ESTALE;
/* Will release the tn_vlock. */
- return node ? tmpfs_vnode_get(mp, node, vpp) : ESTALE;
+ if ((error = tmpfs_vnode_get(mp, node, vpp)) != 0)
+ return error;
+ if (TMPFS_NODE_GEN(node) != tfh.tf_gen) {
+ vput(*vpp);
+ *vpp = NULL;
+ return ESTALE;
+ }
+
+ return 0;
}
static int
