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authorEric W. Biederman <ebiederm@xmission.com>2014-12-22 19:12:07 -0600
committerEric W. Biederman <ebiederm@xmission.com>2015-04-02 20:34:19 -0500
commit411a938b5abc9cb126c41cccf5975ae464fe0f3e (patch)
tree730e8410fbeb2ec8190b9b2352abf80ffd56f0ce
parent590ce4bcbfb4e0462a720a4ad901e84416080bba (diff)
mnt: Delay removal from the mount hash.
- 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. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
-rw-r--r--fs/namespace.c13
-rw-r--r--fs/pnode.c1
2 files changed, 8 insertions, 6 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index d1708147eb45..083e3401a808 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -632,14 +632,17 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
*/
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;
@@ -1336,9 +1339,8 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
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);
}
@@ -1365,6 +1367,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
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);
}
diff --git a/fs/pnode.c b/fs/pnode.c
index ac3aa0d43b90..c27ae38ee250 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -383,7 +383,6 @@ static void __propagate_umount(struct mount *mnt)
*/
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);
}