4.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
commit e0c9c0afd2fc958ffa34b697972721d81df8a56f upstream.
Now that it is possible to lazily unmount an entire mount tree and
leave the individual mounts connected to each other add a new flag
UMOUNT_CONNECTED to umount_tree to force this behavior and use
this flag in detach_mounts.
This closes a bug where the deletion of a file or directory could
trigger an unmount and reveal data under a mount point.
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1350,6 +1350,7 @@ static inline void namespace_lock(void)
enum umount_tree_flags {
UMOUNT_SYNC = 1,
UMOUNT_PROPAGATE = 2,
+ UMOUNT_CONNECTED = 4,
};
/*
* mount_lock must be held
@@ -1388,7 +1389,10 @@ static void umount_tree(struct mount *mn
if (how & UMOUNT_SYNC)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
- disconnect = !IS_MNT_LOCKED_AND_LAZY(p);
+ disconnect = !(((how & UMOUNT_CONNECTED) &&
+ mnt_has_parent(p) &&
+ (p->mnt_parent->mnt.mnt_flags & MNT_UMOUNT)) ||
+ IS_MNT_LOCKED_AND_LAZY(p));
pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt,
disconnect ? &unmounted : NULL);
@@ -1531,7 +1535,7 @@ void __detach_mounts(struct dentry *dent
umount_mnt(p);
}
}
- else umount_tree(mnt, 0);
+ else umount_tree(mnt, UMOUNT_CONNECTED);
}
unlock_mount_hash();
put_mountpoint(mp);
--
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