After
# mount --rbind /tmp /mnt
(on 2.5.68) I have a corrupted namespace. Umounting /mnt fails,
and /proc/mounts contains
...
/dev/root /mnt ext3 rw 0 0
proc /mnt/proc proc rw 0 0
usbfs /mnt/proc/bus/usb usbfs rw 0 0
/dev/hdb5 /mnt/usr reiserfs rw 0 0
...
where of course no directories /mnt/proc or /mnt/usr exist.
This is caused by the fact that copy_tree() thinks that the dentry
it is called with is the root of the filesystem. If it is not,
confusion arose.
This confusion is fixed by the patch (against 2.5.69-bk12) below.
Andries
diff -u --recursive --new-file -X /linux/dontdiff a/fs/namespace.c b/fs/namespace.c
--- a/fs/namespace.c Sun May 18 00:44:23 2003
+++ b/fs/namespace.c Sun May 18 17:17:21 2003
@@ -418,36 +418,54 @@
#endif
}
+static int
+lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
+{
+ while (1) {
+ if (d == dentry)
+ return 1;
+ if (d == NULL || d == d->d_parent)
+ return 0;
+ d = d->d_parent;
+ }
+}
+
static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
{
- struct vfsmount *p, *next, *q, *res;
+ struct vfsmount *res, *p, *q, *r, *s;
+ struct list_head *h;
struct nameidata nd;
- p = mnt;
- res = nd.mnt = q = clone_mnt(p, dentry);
+ res = q = clone_mnt(mnt, dentry);
if (!q)
goto Enomem;
- q->mnt_parent = q;
- q->mnt_mountpoint = p->mnt_mountpoint;
+ q->mnt_mountpoint = mnt->mnt_mountpoint;
+
+ p = mnt;
+ for (h = mnt->mnt_mounts.next; h != &mnt->mnt_mounts; h = h->next) {
+ r = list_entry(h, struct vfsmount, mnt_child);
+ if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry))
+ continue;
- while ( (next = next_mnt(p, mnt)) != NULL) {
- while (p != next->mnt_parent) {
- p = p->mnt_parent;
- q = q->mnt_parent;
+ for (s = r; s; s = next_mnt(s, r)) {
+ while (p != s->mnt_parent) {
+ p = p->mnt_parent;
+ q = q->mnt_parent;
+ }
+ p = s;
+ nd.mnt = q;
+ nd.dentry = p->mnt_mountpoint;
+ q = clone_mnt(p, p->mnt_root);
+ if (!q)
+ goto Enomem;
+ spin_lock(&dcache_lock);
+ list_add_tail(&q->mnt_list, &res->mnt_list);
+ attach_mnt(q, &nd);
+ spin_unlock(&dcache_lock);
}
- p = next;
- nd.mnt = q;
- nd.dentry = p->mnt_mountpoint;
- q = clone_mnt(p, p->mnt_root);
- if (!q)
- goto Enomem;
- spin_lock(&dcache_lock);
- list_add_tail(&q->mnt_list, &res->mnt_list);
- attach_mnt(q, &nd);
- spin_unlock(&dcache_lock);
}
return res;
-Enomem:
+ Enomem:
if (res) {
spin_lock(&dcache_lock);
umount_tree(res);
-
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This archive was generated by hypermail 2b29 : Fri May 23 2003 - 22:00:29 EST