The commit is pushed to "branch-rh7-3.10.0-693.1.1.vz7.37.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.1.1.vz7.37.5
------>
commit 15b70fe6002927ab5929740a277b5b4280515669
Author: Konstantin Khorenko <khore...@virtuozzo.com>
Date: Mon Sep 18 12:12:11 2017 +0300
Revert "revert rh mnt: Honor MNT_LOCKED when detaching mounts"
This reverts commit 0573dc863a9ef9a7c5cba27c8a35c415c7174ae1.
This was a temporary fix for
https://jira.sw.ru/browse/PSBM-71414
The issue will be fixed by next patch.
Signed-off-by: Vasily Averin <v...@virtuozzo.com>
---
fs/namespace.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 52 insertions(+), 3 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 6dbf827..2c98249 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1125,6 +1125,13 @@ static void mntput_no_expire(struct mount *mnt)
rcu_read_unlock();
list_del(&mnt->mnt_instance);
+
+ if (unlikely(!list_empty(&mnt->mnt_mounts))) {
+ struct mount *p, *tmp;
+ list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts, mnt_child) {
+ umount_mnt(p);
+ }
+ }
unlock_mount_hash();
if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) {
@@ -1399,6 +1406,35 @@ enum umount_tree_flags {
UMOUNT_CONNECTED = 4,
};
+static bool disconnect_mount(struct mount *mnt, enum umount_tree_flags how)
+{
+ /* Leaving mounts connected is only valid for lazy umounts */
+ if (how & UMOUNT_SYNC)
+ return true;
+
+ /* A mount without a parent has nothing to be connected to */
+ if (!mnt_has_parent(mnt))
+ return true;
+
+ /* Because the reference counting rules change when mounts are
+ * unmounted and connected, umounted mounts may not be
+ * connected to mounted mounts.
+ */
+ if (!(mnt->mnt_parent->mnt.mnt_flags & MNT_UMOUNT))
+ return true;
+
+ /* Has it been requested that the mount remain connected? */
+ if (how & UMOUNT_CONNECTED)
+ return false;
+
+ /* Is the mount locked such that it needs to remain connected? */
+ if (IS_MNT_LOCKED(mnt))
+ return false;
+
+ /* By default disconnect the mount */
+ return true;
+}
+
/*
* mount_lock must be held
* namespace_sem must be held for write
@@ -1427,6 +1463,7 @@ static void umount_tree(struct mount *mnt, enum
umount_tree_flags how)
propagate_umount(&tmp_list);
while (!list_empty(&tmp_list)) {
+ bool disconnect;
p = list_first_entry(&tmp_list, struct mount, mnt_list);
list_del_init(&p->mnt_expire);
list_del_init(&p->mnt_list);
@@ -1435,10 +1472,18 @@ static void umount_tree(struct mount *mnt, enum
umount_tree_flags how)
if (how & UMOUNT_SYNC)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
- pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt,
&unmounted);
+ disconnect = disconnect_mount(p, how);
+
+ pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt,
+ disconnect ? &unmounted : NULL);
if (mnt_has_parent(p)) {
mnt_add_count(p->mnt_parent, -1);
- umount_mnt(p);
+ if (!disconnect) {
+ /* Don't forget about p */
+ list_add_tail(&p->mnt_child,
&p->mnt_parent->mnt_mounts);
+ } else {
+ umount_mnt(p);
+ }
}
change_mnt_propagation(p, MS_PRIVATE);
}
@@ -1566,7 +1611,11 @@ void __detach_mounts(struct dentry *dentry)
event++;
while (!hlist_empty(&mp->m_list)) {
mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
- umount_tree(mnt, UMOUNT_CONNECTED);
+ if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
+ hlist_add_head(&mnt->mnt_umount.s_list, &unmounted);
+ umount_mnt(mnt);
+ }
+ else umount_tree(mnt, UMOUNT_CONNECTED);
}
put_mountpoint(mp);
out_unlock:
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