On Sun, Jan 16, 2011 at 10:15:31PM +0100, Joachim Eastwood wrote:
> Hi,
>
> On 1/16/11, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> > Al Viro (3):
> > sanitize vfsmount refcounting changes
>
> f03c65993b98eeb909a4012ce7833c5857d74755 - sanitize vfsmount refcounting changes
>
> Breaks my ARM !CONFIG_SMP compile
>
> CC fs/namespace.o
> fs/namespace.c: In function 'commit_tree':
> fs/namespace.c:629: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c: In function 'umount_tree':
> fs/namespace.c:1192: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c: In function 'mnt_make_longterm':
> fs/namespace.c:2246: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c: In function 'mnt_make_shortterm':
> fs/namespace.c:2251: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c:2254: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c: In function 'dup_mnt_ns':
> fs/namespace.c:2295: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c:2299: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c:2305: error: 'struct vfsmount' has no member named 'mnt_longterm'
> fs/namespace.c: In function 'create_mnt_ns':
> fs/namespace.c:2351: error: 'struct vfsmount' has no member named 'mnt_longterm'
Aaaaargh... Brown paperbag time - all testing was on SMP boxen ;-/ The fix
follows. Linus, I've dropped that into for-linus in usual place
(git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6.git/), so if you
prefer to pull it, it's there.
commit 91ed228ab50daa7aca54faa8bf5208b97e3448b8
Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Sun Jan 16 16:32:11 2011 -0500
mnt_longterm is there only on SMP
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
diff --git a/fs/namespace.c b/fs/namespace.c
index 48809e2..9f544f3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -611,6 +611,21 @@ static void attach_mnt(struct vfsmount *mnt, struct path *path)
list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
}
+static inline void __mnt_make_longterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ atomic_inc(&mnt->mnt_longterm);
+#endif
+}
+
+/* needs vfsmount lock for write */
+static inline void __mnt_make_shortterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ atomic_dec(&mnt->mnt_longterm);
+#endif
+}
+
/*
* vfsmount lock must be held for write
*/
@@ -626,7 +641,7 @@ static void commit_tree(struct vfsmount *mnt)
list_add_tail(&head, &mnt->mnt_list);
list_for_each_entry(m, &head, mnt_list) {
m->mnt_ns = n;
- atomic_inc(&m->mnt_longterm);
+ __mnt_make_longterm(m);
}
list_splice(&head, n->list.prev);
@@ -1189,7 +1204,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
- atomic_dec(&p->mnt_longterm);
+ __mnt_make_shortterm(p);
list_del_init(&p->mnt_child);
if (p->mnt_parent != p) {
p->mnt_parent->mnt_ghosts++;
@@ -2243,16 +2258,18 @@ static struct mnt_namespace *alloc_mnt_ns(void)
void mnt_make_longterm(struct vfsmount *mnt)
{
- atomic_inc(&mnt->mnt_longterm);
+ __mnt_make_longterm(mnt);
}
void mnt_make_shortterm(struct vfsmount *mnt)
{
+#ifdef CONFIG_SMP
if (atomic_add_unless(&mnt->mnt_longterm, -1, 1))
return;
br_write_lock(vfsmount_lock);
atomic_dec(&mnt->mnt_longterm);
br_write_unlock(vfsmount_lock);
+#endif
}
/*
@@ -2292,17 +2309,17 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
q = new_ns->root;
while (p) {
q->mnt_ns = new_ns;
- atomic_inc(&q->mnt_longterm);
+ __mnt_make_longterm(q);
if (fs) {
if (p == fs->root.mnt) {
fs->root.mnt = mntget(q);
- atomic_inc(&q->mnt_longterm);
+ __mnt_make_longterm(q);
mnt_make_shortterm(p);
rootmnt = p;
}
if (p == fs->pwd.mnt) {
fs->pwd.mnt = mntget(q);
- atomic_inc(&q->mnt_longterm);
+ __mnt_make_longterm(q);
mnt_make_shortterm(p);
pwdmnt = p;
}
@@ -2348,7 +2365,7 @@ struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt)
new_ns = alloc_mnt_ns();
if (!IS_ERR(new_ns)) {
mnt->mnt_ns = new_ns;
- atomic_inc(&mnt->mnt_longterm);
+ __mnt_make_longterm(mnt);
new_ns->root = mnt;
list_add(&new_ns->list, &new_ns->root->mnt_list);
}
--
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