4.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
commit 411a938b5abc9cb126c41cccf5975ae464fe0f3e upstream.
- Modify __lookup_mnt_hash_last to ignore mounts that have MNT_UMOUNTED set.
- Don't remove mounts from the mount hash table in propogate_umount
- Don't remove mounts from the mount hash table in umount_tree before
the entire list of mounts to be umounted is selected.
- Remove mounts from the mount hash table as the last thing that
happens in the case where a mount has a parent in umount_tree.
Mounts without parents are not hashed (by definition).
This paves the way for delaying removal from the mount hash table even
farther and fixing the MNT_LOCKED vs MNT_DETACH issue.
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 13 ++++++++-----
fs/pnode.c | 1 -
2 files changed, 8 insertions(+), 6 deletions(-)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -632,14 +632,17 @@ struct mount *__lookup_mnt(struct vfsmou
*/
struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry)
{
- struct mount *p, *res;
- res = p = __lookup_mnt(mnt, dentry);
+ struct mount *p, *res = NULL;
+ p = __lookup_mnt(mnt, dentry);
if (!p)
goto out;
+ if (!(p->mnt.mnt_flags & MNT_UMOUNT))
+ res = p;
hlist_for_each_entry_continue(p, mnt_hash) {
if (&p->mnt_parent->mnt != mnt || p->mnt_mountpoint != dentry)
break;
- res = p;
+ if (!(p->mnt.mnt_flags & MNT_UMOUNT))
+ res = p;
}
out:
return res;
@@ -1338,9 +1341,8 @@ static void umount_tree(struct mount *mn
list_move(&p->mnt_list, &tmp_list);
}
- /* Hide the mounts from lookup_mnt and mnt_mounts */
+ /* Hide the mounts from mnt_mounts */
list_for_each_entry(p, &tmp_list, mnt_list) {
- hlist_del_init_rcu(&p->mnt_hash);
list_del_init(&p->mnt_child);
}
@@ -1367,6 +1369,7 @@ static void umount_tree(struct mount *mn
p->mnt_mountpoint = p->mnt.mnt_root;
p->mnt_parent = p;
p->mnt_mp = NULL;
+ hlist_del_init_rcu(&p->mnt_hash);
}
change_mnt_propagation(p, MS_PRIVATE);
}
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -383,7 +383,6 @@ static void __propagate_umount(struct mo
*/
if (child && list_empty(&child->mnt_mounts)) {
list_del_init(&child->mnt_child);
- hlist_del_init_rcu(&child->mnt_hash);
child->mnt.mnt_flags |= MNT_UMOUNT;
list_move_tail(&child->mnt_list, &mnt->mnt_list);
}
--
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