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