unsigned int mnt_get_count(struct vfsmount *mnt)
{
#ifdef CONFIG_SMP
- unsigned int count = atomic_read(&mnt->mnt_longrefs);
+ unsigned int count = 0;
int cpu;
for_each_possible_cpu(cpu) {
if (!mnt->mnt_pcp)
goto out_free_devname;
- atomic_set(&mnt->mnt_longrefs, 1);
+ this_cpu_add(mnt->mnt_pcp->mnt_count, 1);
#else
mnt->mnt_count = 1;
mnt->mnt_writers = 0;
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
*/
BUG_ON(parent == mnt);
list_add_tail(&head, &mnt->mnt_list);
- list_for_each_entry(m, &head, mnt_list)
+ list_for_each_entry(m, &head, mnt_list) {
m->mnt_ns = n;
+ __mnt_make_longterm(m);
+ }
+
list_splice(&head, n->list.prev);
list_add_tail(&mnt->mnt_hash, mount_hashtable +
deactivate_super(sb);
}
-#ifdef CONFIG_SMP
-static inline void __mntput(struct vfsmount *mnt, int longrefs)
+static void mntput_no_expire(struct vfsmount *mnt)
{
- if (!longrefs) {
put_again:
- br_read_lock(vfsmount_lock);
- if (likely(atomic_read(&mnt->mnt_longrefs))) {
- mnt_dec_count(mnt);
- br_read_unlock(vfsmount_lock);
- return;
- }
+#ifdef CONFIG_SMP
+ br_read_lock(vfsmount_lock);
+ if (likely(atomic_read(&mnt->mnt_longterm))) {
+ mnt_dec_count(mnt);
br_read_unlock(vfsmount_lock);
- } else {
- BUG_ON(!atomic_read(&mnt->mnt_longrefs));
- if (atomic_add_unless(&mnt->mnt_longrefs, -1, 1))
- return;
+ return;
}
+ br_read_unlock(vfsmount_lock);
br_write_lock(vfsmount_lock);
- if (!longrefs)
- mnt_dec_count(mnt);
- else
- atomic_dec(&mnt->mnt_longrefs);
+ mnt_dec_count(mnt);
if (mnt_get_count(mnt)) {
br_write_unlock(vfsmount_lock);
return;
}
- if (unlikely(mnt->mnt_pinned)) {
- mnt_add_count(mnt, mnt->mnt_pinned + 1);
- mnt->mnt_pinned = 0;
- br_write_unlock(vfsmount_lock);
- acct_auto_close_mnt(mnt);
- goto put_again;
- }
- br_write_unlock(vfsmount_lock);
- mntfree(mnt);
-}
#else
-static inline void __mntput(struct vfsmount *mnt, int longrefs)
-{
-put_again:
mnt_dec_count(mnt);
if (likely(mnt_get_count(mnt)))
return;
br_write_lock(vfsmount_lock);
+#endif
if (unlikely(mnt->mnt_pinned)) {
mnt_add_count(mnt, mnt->mnt_pinned + 1);
mnt->mnt_pinned = 0;
br_write_unlock(vfsmount_lock);
mntfree(mnt);
}
-#endif
-
-static void mntput_no_expire(struct vfsmount *mnt)
-{
- __mntput(mnt, 0);
-}
void mntput(struct vfsmount *mnt)
{
/* avoid cacheline pingpong, hope gcc doesn't get "smart" */
if (unlikely(mnt->mnt_expiry_mark))
mnt->mnt_expiry_mark = 0;
- __mntput(mnt, 0);
+ mntput_no_expire(mnt);
}
}
EXPORT_SYMBOL(mntput);
}
EXPORT_SYMBOL(mntget);
-void mntput_long(struct vfsmount *mnt)
-{
-#ifdef CONFIG_SMP
- if (mnt) {
- /* avoid cacheline pingpong, hope gcc doesn't get "smart" */
- if (unlikely(mnt->mnt_expiry_mark))
- mnt->mnt_expiry_mark = 0;
- __mntput(mnt, 1);
- }
-#else
- mntput(mnt);
-#endif
-}
-EXPORT_SYMBOL(mntput_long);
-
-struct vfsmount *mntget_long(struct vfsmount *mnt)
-{
-#ifdef CONFIG_SMP
- if (mnt)
- atomic_inc(&mnt->mnt_longrefs);
- return mnt;
-#else
- return mntget(mnt);
-#endif
-}
-EXPORT_SYMBOL(mntget_long);
-
void mnt_pin(struct vfsmount *mnt)
{
br_write_lock(vfsmount_lock);
dput(dentry);
mntput(m);
}
- mntput_long(mnt);
+ mntput(mnt);
}
}
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
+ __mnt_make_shortterm(p);
list_del_init(&p->mnt_child);
if (p->mnt_parent != p) {
p->mnt_parent->mnt_ghosts++;
*/
br_write_lock(vfsmount_lock);
if (mnt_get_count(mnt) != 2) {
- br_write_lock(vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
return -EBUSY;
}
br_write_unlock(vfsmount_lock);
return err;
}
+static int do_add_mount(struct vfsmount *, struct path *, int);
+
/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
int mnt_flags, char *name, void *data)
{
struct vfsmount *mnt;
+ int err;
if (!type)
return -EINVAL;
if (IS_ERR(mnt))
return PTR_ERR(mnt);
- return do_add_mount(mnt, path, mnt_flags);
+ err = do_add_mount(mnt, path, mnt_flags);
+ if (err)
+ mntput(mnt);
+ return err;
+}
+
+int finish_automount(struct vfsmount *m, struct path *path)
+{
+ int err;
+ /* The new mount record should have at least 2 refs to prevent it being
+ * expired before we get a chance to add it
+ */
+ BUG_ON(mnt_get_count(m) < 2);
+
+ if (m->mnt_sb == path->mnt->mnt_sb &&
+ m->mnt_root == path->dentry) {
+ err = -ELOOP;
+ goto fail;
+ }
+
+ err = do_add_mount(m, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+ if (!err)
+ return 0;
+fail:
+ /* remove m from any expiration list it may be on */
+ if (!list_empty(&m->mnt_expire)) {
+ down_write(&namespace_sem);
+ br_write_lock(vfsmount_lock);
+ list_del_init(&m->mnt_expire);
+ br_write_unlock(vfsmount_lock);
+ up_write(&namespace_sem);
+ }
+ mntput(m);
+ mntput(m);
+ return err;
}
/*
* add a mount into a namespace's mount tree
- * - this unconditionally eats one of the caller's references to newmnt.
*/
-int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)
+static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)
{
int err;
goto unlock;
newmnt->mnt_flags = mnt_flags;
- if ((err = graft_tree(newmnt, path)))
- goto unlock;
-
- up_write(&namespace_sem);
- return 0;
+ err = graft_tree(newmnt, path);
unlock:
up_write(&namespace_sem);
- mntput_long(newmnt);
return err;
}
}
EXPORT_SYMBOL(mnt_set_expiry);
-/*
- * Remove a vfsmount from any expiration list it may be on
- */
-void mnt_clear_expiry(struct vfsmount *mnt)
-{
- if (!list_empty(&mnt->mnt_expire)) {
- down_write(&namespace_sem);
- br_write_lock(vfsmount_lock);
- list_del_init(&mnt->mnt_expire);
- br_write_unlock(vfsmount_lock);
- up_write(&namespace_sem);
- }
-}
-
/*
* process a list of expirable mountpoints with the intent of discarding any
* mountpoints that aren't in use and haven't been touched since last we came
return new_ns;
}
+void mnt_make_longterm(struct vfsmount *mnt)
+{
+ __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
+}
+
/*
* Allocate a new namespace structure and populate it with contents
* copied from the namespace of the passed in task structure.
q = new_ns->root;
while (p) {
q->mnt_ns = new_ns;
+ __mnt_make_longterm(q);
if (fs) {
if (p == fs->root.mnt) {
+ fs->root.mnt = mntget(q);
+ __mnt_make_longterm(q);
+ mnt_make_shortterm(p);
rootmnt = p;
- fs->root.mnt = mntget_long(q);
}
if (p == fs->pwd.mnt) {
+ fs->pwd.mnt = mntget(q);
+ __mnt_make_longterm(q);
+ mnt_make_shortterm(p);
pwdmnt = p;
- fs->pwd.mnt = mntget_long(q);
}
}
p = next_mnt(p, mnt_ns->root);
up_write(&namespace_sem);
if (rootmnt)
- mntput_long(rootmnt);
+ mntput(rootmnt);
if (pwdmnt)
- mntput_long(pwdmnt);
+ mntput(pwdmnt);
return new_ns;
}
new_ns = alloc_mnt_ns();
if (!IS_ERR(new_ns)) {
mnt->mnt_ns = new_ns;
+ __mnt_make_longterm(mnt);
new_ns->root = mnt;
list_add(&new_ns->list, &new_ns->root->mnt_list);
}
projects / mv-sheeva.git / blobdiff