Module Name: src
Committed By: hannken
Date: Mon Feb 10 11:23:14 UTC 2014
Modified Files:
src/sys/miscfs/genfs: layer_subr.c layer_vfsops.c
src/sys/miscfs/nullfs: null_vfsops.c
src/sys/miscfs/overlay: overlay_vfsops.c
src/sys/miscfs/umapfs: umap_vfsops.c
Log Message:
Change layerfs_vget(), layerfs_fhtovp() and the various layer xxx_mount()
functions to unlock/relock the node for the call to layer_node_create().
Finally remove dirty hacks (LK_NOWAIT, kpause) from layer_node_find().
To generate a diff of this commit:
cvs rdiff -u -r1.34 -r1.35 src/sys/miscfs/genfs/layer_subr.c
cvs rdiff -u -r1.41 -r1.42 src/sys/miscfs/genfs/layer_vfsops.c
cvs rdiff -u -r1.84 -r1.85 src/sys/miscfs/nullfs/null_vfsops.c
cvs rdiff -u -r1.57 -r1.58 src/sys/miscfs/overlay/overlay_vfsops.c
cvs rdiff -u -r1.88 -r1.89 src/sys/miscfs/umapfs/umap_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/miscfs/genfs/layer_subr.c
diff -u src/sys/miscfs/genfs/layer_subr.c:1.34 src/sys/miscfs/genfs/layer_subr.c:1.35
--- src/sys/miscfs/genfs/layer_subr.c:1.34 Sun Feb 9 17:15:51 2014
+++ src/sys/miscfs/genfs/layer_subr.c Mon Feb 10 11:23:14 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: layer_subr.c,v 1.34 2014/02/09 17:15:51 hannken Exp $ */
+/* $NetBSD: layer_subr.c,v 1.35 2014/02/10 11:23:14 hannken Exp $ */
/*
* Copyright (c) 1999 National Aeronautics & Space Administration
@@ -69,7 +69,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: layer_subr.c,v 1.34 2014/02/09 17:15:51 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: layer_subr.c,v 1.35 2014/02/10 11:23:14 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -112,7 +112,7 @@ layerfs_done(void)
/*
* layer_node_find: find and return alias for lower vnode or NULL.
*
- * => Return alias vnode locked and referenced. if already exists.
+ * => Return alias vnode referenced. if already exists.
* => The layermp's hashlock must be held on entry, we will unlock on success.
*/
struct vnode *
@@ -128,7 +128,7 @@ layer_node_find(struct mount *mp, struct
* Find hash bucket and search the (two-way) linked list looking
* for a layerfs node structure which is referencing the lower vnode.
* If found, the increment the layer_node reference count, but NOT
- * the lower vnode's reference counter. Return vnode locked.
+ * the lower vnode's reference counter.
*/
KASSERT(mutex_owned(&lmp->layerm_hashlock));
hd = LAYER_NHASH(lmp, lowervp);
@@ -142,29 +142,9 @@ loop:
continue;
}
mutex_enter(vp->v_interlock);
- /*
- * If we find a node being cleaned out, then ignore it and
- * continue. A thread trying to clean out the extant layer
- * vnode needs to acquire the shared lock (i.e. the lower
- * vnode's lock), which our caller already holds. To allow
- * the cleaning to succeed the current thread must make
- * progress. So, for a brief time more than one vnode in a
- * layered file system may refer to a single vnode in the
- * lower file system.
- */
- if ((vp->v_iflag & VI_XLOCK) != 0) {
- mutex_exit(vp->v_interlock);
- continue;
- }
mutex_exit(&lmp->layerm_hashlock);
- /*
- * We must not let vget() try to lock the layer vp, since
- * the lower vp is already locked and locking the layer vp
- * will involve locking the lower vp.
- */
- error = vget(vp, LK_NOWAIT);
+ error = vget(vp, 0);
if (error) {
- kpause("layerfs", false, 1, NULL);
mutex_enter(&lmp->layerm_hashlock);
goto loop;
}
Index: src/sys/miscfs/genfs/layer_vfsops.c
diff -u src/sys/miscfs/genfs/layer_vfsops.c:1.41 src/sys/miscfs/genfs/layer_vfsops.c:1.42
--- src/sys/miscfs/genfs/layer_vfsops.c:1.41 Thu May 31 16:08:14 2012
+++ src/sys/miscfs/genfs/layer_vfsops.c Mon Feb 10 11:23:14 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: layer_vfsops.c,v 1.41 2012/05/31 16:08:14 pgoyette Exp $ */
+/* $NetBSD: layer_vfsops.c,v 1.42 2014/02/10 11:23:14 hannken Exp $ */
/*
* Copyright (c) 1999 National Aeronautics & Space Administration
@@ -74,7 +74,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: layer_vfsops.c,v 1.41 2012/05/31 16:08:14 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: layer_vfsops.c,v 1.42 2014/02/10 11:23:14 hannken Exp $");
#include <sys/param.h>
#include <sys/sysctl.h>
@@ -214,9 +214,16 @@ layerfs_vget(struct mount *mp, ino_t ino
*vpp = NULL;
return error;
}
+ VOP_UNLOCK(vp);
error = layer_node_create(mp, vp, vpp);
if (error) {
- vput(vp);
+ vrele(vp);
+ *vpp = NULL;
+ return error;
+ }
+ error = vn_lock(*vpp, LK_EXCLUSIVE);
+ if (error) {
+ vrele(*vpp);
*vpp = NULL;
return error;
}
@@ -231,14 +238,22 @@ layerfs_fhtovp(struct mount *mp, struct
error = VFS_FHTOVP(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, fidp, &vp);
if (error) {
+ *vpp = NULL;
return error;
}
+ VOP_UNLOCK(vp);
error = layer_node_create(mp, vp, vpp);
if (error) {
vput(vp);
*vpp = NULL;
return (error);
}
+ error = vn_lock(*vpp, LK_EXCLUSIVE);
+ if (error) {
+ vrele(*vpp);
+ *vpp = NULL;
+ return error;
+ }
return 0;
}
Index: src/sys/miscfs/nullfs/null_vfsops.c
diff -u src/sys/miscfs/nullfs/null_vfsops.c:1.84 src/sys/miscfs/nullfs/null_vfsops.c:1.85
--- src/sys/miscfs/nullfs/null_vfsops.c:1.84 Mon Apr 30 22:51:27 2012
+++ src/sys/miscfs/nullfs/null_vfsops.c Mon Feb 10 11:23:14 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: null_vfsops.c,v 1.84 2012/04/30 22:51:27 rmind Exp $ */
+/* $NetBSD: null_vfsops.c,v 1.85 2014/02/10 11:23:14 hannken Exp $ */
/*
* Copyright (c) 1999 National Aeronautics & Space Administration
@@ -76,7 +76,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.84 2012/04/30 22:51:27 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.85 2014/02/10 11:23:14 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -159,9 +159,10 @@ nullfs_mount(struct mount *mp, const cha
&nmp->nullm_node_hash);
/* Setup a null node for root vnode. */
+ VOP_UNLOCK(lowerrootvp);
error = layer_node_create(mp, lowerrootvp, &vp);
if (error) {
- vput(lowerrootvp);
+ vrele(lowerrootvp);
hashdone(nmp->nullm_node_hashtbl, HASH_LIST,
nmp->nullm_node_hash);
kmem_free(nmp, sizeof(struct null_mount));
@@ -171,6 +172,7 @@ nullfs_mount(struct mount *mp, const cha
* Keep a held reference to the root vnode. It will be released on
* umount. Note: nullfs is MP-safe.
*/
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vp->v_vflag |= VV_ROOT;
nmp->nullm_rootvp = vp;
mp->mnt_iflag |= IMNT_MPSAFE;
Index: src/sys/miscfs/overlay/overlay_vfsops.c
diff -u src/sys/miscfs/overlay/overlay_vfsops.c:1.57 src/sys/miscfs/overlay/overlay_vfsops.c:1.58
--- src/sys/miscfs/overlay/overlay_vfsops.c:1.57 Mon Apr 30 22:51:27 2012
+++ src/sys/miscfs/overlay/overlay_vfsops.c Mon Feb 10 11:23:14 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: overlay_vfsops.c,v 1.57 2012/04/30 22:51:27 rmind Exp $ */
+/* $NetBSD: overlay_vfsops.c,v 1.58 2014/02/10 11:23:14 hannken Exp $ */
/*
* Copyright (c) 1999, 2000 National Aeronautics & Space Administration
@@ -74,7 +74,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.57 2012/04/30 22:51:27 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.58 2014/02/10 11:23:14 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -170,27 +170,26 @@ ov_mount(struct mount *mp, const char *p
/*
* Fix up overlay node for root vnode
*/
+ VOP_UNLOCK(lowerrootvp);
error = layer_node_create(mp, lowerrootvp, &vp);
/*
* Make sure the fixup worked
*/
if (error) {
- vput(lowerrootvp);
+ vrele(lowerrootvp);
hashdone(nmp->ovm_node_hashtbl, HASH_LIST, nmp->ovm_node_hash);
kmem_free(nmp, sizeof(struct overlay_mount));
return error;
}
- /*
- * Unlock the node
- */
- VOP_UNLOCK(vp);
/*
* Keep a held reference to the root vnode.
* It is vrele'd in ov_unmount.
*/
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vp->v_vflag |= VV_ROOT;
nmp->ovm_rootvp = vp;
+ VOP_UNLOCK(vp);
error = set_statvfs_info(path, UIO_USERSPACE, args->la.target,
UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
Index: src/sys/miscfs/umapfs/umap_vfsops.c
diff -u src/sys/miscfs/umapfs/umap_vfsops.c:1.88 src/sys/miscfs/umapfs/umap_vfsops.c:1.89
--- src/sys/miscfs/umapfs/umap_vfsops.c:1.88 Mon Apr 30 22:51:28 2012
+++ src/sys/miscfs/umapfs/umap_vfsops.c Mon Feb 10 11:23:14 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: umap_vfsops.c,v 1.88 2012/04/30 22:51:28 rmind Exp $ */
+/* $NetBSD: umap_vfsops.c,v 1.89 2014/02/10 11:23:14 hannken Exp $ */
/*
* Copyright (c) 1992, 1993
@@ -41,7 +41,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: umap_vfsops.c,v 1.88 2012/04/30 22:51:28 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: umap_vfsops.c,v 1.89 2014/02/10 11:23:14 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -205,28 +205,27 @@ umapfs_mount(struct mount *mp, const cha
/*
* fix up umap node for root vnode.
*/
+ VOP_UNLOCK(lowerrootvp);
error = layer_node_create(mp, lowerrootvp, &vp);
/*
* Make sure the node alias worked
*/
if (error) {
- vput(lowerrootvp);
+ vrele(lowerrootvp);
hashdone(amp->umapm_node_hashtbl, HASH_LIST,
amp->umapm_node_hash);
kmem_free(amp, sizeof(struct umap_mount));
return error;
}
- /*
- * Unlock the node (either the lower or the alias)
- */
- vp->v_vflag |= VV_ROOT;
- VOP_UNLOCK(vp);
/*
* Keep a held reference to the root vnode.
* It is vrele'd in umapfs_unmount.
*/
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+ vp->v_vflag |= VV_ROOT;
amp->umapm_rootvp = vp;
+ VOP_UNLOCK(vp);
error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
