diff options
| author | Eric W. Biederman <ebiederman@twitter.com> | 2013-09-22 19:37:01 -0700 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-10-09 02:38:54 -0400 |
| commit | 0a5eb7c8189922e86a840972cd0b57e41de6f031 (patch) | |
| tree | ee3f026727cff4acf5d7adbd7674d4177677f12f | |
| parent | 7af1364ffa64db61e386628594836e13d2ef04b5 (diff) | |
vfs: Keep a list of mounts on a mount point
To spot any possible problems call BUG if a mountpoint
is put when it's list of mounts is not empty.
AV: use hlist instead of list_head
Reviewed-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Eric W. Biederman <ebiederman@twitter.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/mount.h | 2 | ||||
| -rw-r--r-- | fs/namespace.c | 6 |
2 files changed, 8 insertions, 0 deletions
diff --git a/fs/mount.h b/fs/mount.h index 8c6a2a65125..68bb03ed7f1 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -21,6 +21,7 @@ struct mnt_pcp { struct mountpoint { struct hlist_node m_hash; struct dentry *m_dentry; + struct hlist_head m_list; int m_count; }; @@ -51,6 +52,7 @@ struct mount { struct mount *mnt_master; /* slave is on master->mnt_slave_list */ struct mnt_namespace *mnt_ns; /* containing namespace */ struct mountpoint *mnt_mp; /* where is it mounted */ + struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ #ifdef CONFIG_FSNOTIFY struct hlist_head mnt_fsnotify_marks; __u32 mnt_fsnotify_mask; diff --git a/fs/namespace.c b/fs/namespace.c index 77ffdb82f63..99572dd0833 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -225,6 +225,7 @@ static struct mount *alloc_vfsmnt(const char *name) INIT_LIST_HEAD(&mnt->mnt_share); INIT_LIST_HEAD(&mnt->mnt_slave_list); INIT_LIST_HEAD(&mnt->mnt_slave); + INIT_HLIST_NODE(&mnt->mnt_mp_list); #ifdef CONFIG_FSNOTIFY INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks); #endif @@ -731,6 +732,7 @@ static struct mountpoint *new_mountpoint(struct dentry *dentry) mp->m_dentry = dentry; mp->m_count = 1; hlist_add_head(&mp->m_hash, chain); + INIT_HLIST_HEAD(&mp->m_list); return mp; } @@ -738,6 +740,7 @@ static void put_mountpoint(struct mountpoint *mp) { if (!--mp->m_count) { struct dentry *dentry = mp->m_dentry; + BUG_ON(!hlist_empty(&mp->m_list)); spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_MOUNTED; spin_unlock(&dentry->d_lock); @@ -784,6 +787,7 @@ static void detach_mnt(struct mount *mnt, struct path *old_path) mnt->mnt_mountpoint = mnt->mnt.mnt_root; list_del_init(&mnt->mnt_child); hlist_del_init_rcu(&mnt->mnt_hash); + hlist_del_init(&mnt->mnt_mp_list); put_mountpoint(mnt->mnt_mp); mnt->mnt_mp = NULL; } @@ -800,6 +804,7 @@ void mnt_set_mountpoint(struct mount *mnt, child_mnt->mnt_mountpoint = dget(mp->m_dentry); child_mnt->mnt_parent = mnt; child_mnt->mnt_mp = mp; + hlist_add_head(&child_mnt->mnt_mp_list, &mp->m_list); } /* @@ -1342,6 +1347,7 @@ void umount_tree(struct mount *mnt, int how) if (how < 2) p->mnt.mnt_flags |= MNT_SYNC_UMOUNT; if (mnt_has_parent(p)) { + hlist_del_init(&p->mnt_mp_list); put_mountpoint(p->mnt_mp); mnt_add_count(p->mnt_parent, -1); /* move the reference to mountpoint into ->mnt_ex_mountpoint */ |