Author: pjd
Date: Sat Aug 28 08:57:15 2010
New Revision: 211930
URL: http://svn.freebsd.org/changeset/base/211930
Log:
There is a bug in vfs_allocate_syncvnode() failure handling in mount code.
Actually it is hard to properly handle such a failure, especially in
MNT_UPDATE
case. The only reason for the vfs_allocate_syncvnode() function to fail is
getnewvnode() failure. Fortunately it is impossible for current implementation
of getnewvnode() to fail, so we can assert this and make
vfs_allocate_syncvnode() void. This in turn free us from handling its failures
in the mount code.
Reviewed by: kib
MFC after: 1 month
Modified:
head/sys/kern/vfs_mount.c
head/sys/kern/vfs_subr.c
head/sys/sys/mount.h
Modified: head/sys/kern/vfs_mount.c
==============================================================================
--- head/sys/kern/vfs_mount.c Sat Aug 28 08:39:37 2010 (r211929)
+++ head/sys/kern/vfs_mount.c Sat Aug 28 08:57:15 2010 (r211930)
@@ -1036,7 +1036,7 @@ vfs_domount(
MNT_IUNLOCK(mp);
if ((mp->mnt_flag & MNT_RDONLY) == 0) {
if (mp->mnt_syncer == NULL)
- error = vfs_allocate_syncvnode(mp);
+ vfs_allocate_syncvnode(mp);
} else {
if (mp->mnt_syncer != NULL)
vrele(mp->mnt_syncer);
@@ -1078,10 +1078,8 @@ vfs_domount(
mountcheckdirs(vp, newdp);
vrele(newdp);
if ((mp->mnt_flag & MNT_RDONLY) == 0)
- error = vfs_allocate_syncvnode(mp);
+ vfs_allocate_syncvnode(mp);
vfs_unbusy(mp);
- if (error)
- vrele(vp);
} else {
vfs_unbusy(mp);
vfs_mount_destroy(mp);
@@ -1311,7 +1309,7 @@ dounmount(mp, flags, td)
mp->mnt_kern_flag &= ~MNTK_NOINSMNTQ;
if ((mp->mnt_flag & MNT_RDONLY) == 0 && mp->mnt_syncer == NULL)
{
MNT_IUNLOCK(mp);
- (void) vfs_allocate_syncvnode(mp);
+ vfs_allocate_syncvnode(mp);
MNT_ILOCK(mp);
}
mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c Sat Aug 28 08:39:37 2010 (r211929)
+++ head/sys/kern/vfs_subr.c Sat Aug 28 08:57:15 2010 (r211930)
@@ -3365,7 +3365,7 @@ static struct vop_vector sync_vnodeops =
/*
* Create a new filesystem syncer vnode for the specified mount point.
*/
-int
+void
vfs_allocate_syncvnode(struct mount *mp)
{
struct vnode *vp;
@@ -3374,16 +3374,15 @@ vfs_allocate_syncvnode(struct mount *mp)
int error;
/* Allocate a new vnode */
- if ((error = getnewvnode("syncer", mp, &sync_vnodeops, &vp)) != 0) {
- mp->mnt_syncer = NULL;
- return (error);
- }
+ error = getnewvnode("syncer", mp, &sync_vnodeops, &vp);
+ if (error != 0)
+ panic("vfs_allocate_syncvnode: getnewvnode() failed");
vp->v_type = VNON;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vp->v_vflag |= VV_FORCEINSMQ;
error = insmntque(vp, mp);
if (error != 0)
- panic("vfs_allocate_syncvnode: insmntque failed");
+ panic("vfs_allocate_syncvnode: insmntque() failed");
vp->v_vflag &= ~VV_FORCEINSMQ;
VOP_UNLOCK(vp, 0);
/*
@@ -3411,7 +3410,6 @@ vfs_allocate_syncvnode(struct mount *mp)
mtx_unlock(&sync_mtx);
BO_UNLOCK(bo);
mp->mnt_syncer = vp;
- return (0);
}
/*
Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h Sat Aug 28 08:39:37 2010 (r211929)
+++ head/sys/sys/mount.h Sat Aug 28 08:57:15 2010 (r211930)
@@ -730,7 +730,7 @@ void vfs_msync(struct mount *, int);
int vfs_busy(struct mount *, int);
int vfs_export /* process mount export info */
(struct mount *, struct export_args *);
-int vfs_allocate_syncvnode(struct mount *);
+void vfs_allocate_syncvnode(struct mount *);
int vfs_donmount(struct thread *td, int fsflags, struct uio *fsoptions);
void vfs_getnewfsid(struct mount *);
struct cdev *vfs_getrootfsid(struct mount *);
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