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authorAl Viro <viro@zeniv.linux.org.uk>2016-11-20 19:33:09 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2016-12-16 16:30:49 -0500
commit5235d448c48e1f5a4a34bf90d412775cb75ffb32 (patch)
treef4bbb063b81ba920fffe16fd12bfc0d01db05673 /fs/pnode.c
parent066715d3fde4834cbbec88d12ca277c4185b9303 (diff)
reorganize do_make_slave()
Make sure that clone_mnt() never returns a mount with MNT_SHARED in flags, but without a valid ->mnt_group_id. That allows to demystify do_make_slave() quite a bit, among other things. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/pnode.c')
-rw-r--r--fs/pnode.c74
1 files changed, 36 insertions, 38 deletions
diff --git a/fs/pnode.c b/fs/pnode.c
index 234a9ac49958..06a793f4ae38 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -67,49 +67,47 @@ int get_dominating_id(struct mount *mnt, const struct path *root)
static int do_make_slave(struct mount *mnt)
{
- struct mount *peer_mnt = mnt, *master = mnt->mnt_master;
- struct mount *slave_mnt;
+ struct mount *master, *slave_mnt;
- /*
- * slave 'mnt' to a peer mount that has the
- * same root dentry. If none is available then
- * slave it to anything that is available.
- */
- while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
- peer_mnt->mnt.mnt_root != mnt->mnt.mnt_root) ;
-
- if (peer_mnt == mnt) {
- peer_mnt = next_peer(mnt);
- if (peer_mnt == mnt)
- peer_mnt = NULL;
- }
- if (mnt->mnt_group_id && IS_MNT_SHARED(mnt) &&
- list_empty(&mnt->mnt_share))
- mnt_release_group_id(mnt);
-
- list_del_init(&mnt->mnt_share);
- mnt->mnt_group_id = 0;
-
- if (peer_mnt)
- master = peer_mnt;
-
- if (master) {
- list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
- slave_mnt->mnt_master = master;
- list_move(&mnt->mnt_slave, &master->mnt_slave_list);
- list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
- INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ if (list_empty(&mnt->mnt_share)) {
+ if (IS_MNT_SHARED(mnt)) {
+ mnt_release_group_id(mnt);
+ CLEAR_MNT_SHARED(mnt);
+ }
+ master = mnt->mnt_master;
+ if (!master) {
+ struct list_head *p = &mnt->mnt_slave_list;
+ while (!list_empty(p)) {
+ slave_mnt = list_first_entry(p,
+ struct mount, mnt_slave);
+ list_del_init(&slave_mnt->mnt_slave);
+ slave_mnt->mnt_master = NULL;
+ }
+ return 0;
+ }
} else {
- struct list_head *p = &mnt->mnt_slave_list;
- while (!list_empty(p)) {
- slave_mnt = list_first_entry(p,
- struct mount, mnt_slave);
- list_del_init(&slave_mnt->mnt_slave);
- slave_mnt->mnt_master = NULL;
+ struct mount *m;
+ /*
+ * slave 'mnt' to a peer mount that has the
+ * same root dentry. If none is available then
+ * slave it to anything that is available.
+ */
+ for (m = master = next_peer(mnt); m != mnt; m = next_peer(m)) {
+ if (m->mnt.mnt_root == mnt->mnt.mnt_root) {
+ master = m;
+ break;
+ }
}
+ list_del_init(&mnt->mnt_share);
+ mnt->mnt_group_id = 0;
+ CLEAR_MNT_SHARED(mnt);
}
+ list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
+ slave_mnt->mnt_master = master;
+ list_move(&mnt->mnt_slave, &master->mnt_slave_list);
+ list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
mnt->mnt_master = master;
- CLEAR_MNT_SHARED(mnt);
return 0;
}