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Diffstat (limited to 'fs')
-rw-r--r--fs/namespace.c93
-rw-r--r--fs/pnode.c5
2 files changed, 94 insertions, 4 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 8ca6317cb40..cefa1d9939b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -41,6 +41,7 @@ __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
static int event;
static DEFINE_IDA(mnt_id_ida);
+static DEFINE_IDA(mnt_group_ida);
static struct list_head *mount_hashtable __read_mostly;
static struct kmem_cache *mnt_cache __read_mostly;
@@ -83,6 +84,28 @@ static void mnt_free_id(struct vfsmount *mnt)
spin_unlock(&vfsmount_lock);
}
+/*
+ * Allocate a new peer group ID
+ *
+ * mnt_group_ida is protected by namespace_sem
+ */
+static int mnt_alloc_group_id(struct vfsmount *mnt)
+{
+ if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL))
+ return -ENOMEM;
+
+ return ida_get_new_above(&mnt_group_ida, 1, &mnt->mnt_group_id);
+}
+
+/*
+ * Release a peer group ID
+ */
+void mnt_release_group_id(struct vfsmount *mnt)
+{
+ ida_remove(&mnt_group_ida, mnt->mnt_group_id);
+ mnt->mnt_group_id = 0;
+}
+
struct vfsmount *alloc_vfsmnt(const char *name)
{
struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
@@ -533,6 +556,17 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
if (mnt) {
+ if (flag & (CL_SLAVE | CL_PRIVATE))
+ mnt->mnt_group_id = 0; /* not a peer of original */
+ else
+ mnt->mnt_group_id = old->mnt_group_id;
+
+ if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
+ int err = mnt_alloc_group_id(mnt);
+ if (err)
+ goto out_free;
+ }
+
mnt->mnt_flags = old->mnt_flags;
atomic_inc(&sb->s_active);
mnt->mnt_sb = sb;
@@ -562,6 +596,10 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
}
}
return mnt;
+
+ out_free:
+ free_vfsmnt(mnt);
+ return NULL;
}
static inline void __mntput(struct vfsmount *mnt)
@@ -1142,6 +1180,33 @@ void drop_collected_mounts(struct vfsmount *mnt)
release_mounts(&umount_list);
}
+static void cleanup_group_ids(struct vfsmount *mnt, struct vfsmount *end)
+{
+ struct vfsmount *p;
+
+ for (p = mnt; p != end; p = next_mnt(p, mnt)) {
+ if (p->mnt_group_id && !IS_MNT_SHARED(p))
+ mnt_release_group_id(p);
+ }
+}
+
+static int invent_group_ids(struct vfsmount *mnt, bool recurse)
+{
+ struct vfsmount *p;
+
+ for (p = mnt; p; p = recurse ? next_mnt(p, mnt) : NULL) {
+ if (!p->mnt_group_id && !IS_MNT_SHARED(p)) {
+ int err = mnt_alloc_group_id(p);
+ if (err) {
+ cleanup_group_ids(mnt, p);
+ return err;
+ }
+ }
+ }
+
+ return 0;
+}
+
/*
* @source_mnt : mount tree to be attached
* @nd : place the mount tree @source_mnt is attached
@@ -1212,9 +1277,16 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
struct vfsmount *dest_mnt = path->mnt;
struct dentry *dest_dentry = path->dentry;
struct vfsmount *child, *p;
+ int err;
- if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
- return -EINVAL;
+ if (IS_MNT_SHARED(dest_mnt)) {
+ err = invent_group_ids(source_mnt, true);
+ if (err)
+ goto out;
+ }
+ err = propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list);
+ if (err)
+ goto out_cleanup_ids;
if (IS_MNT_SHARED(dest_mnt)) {
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
@@ -1237,6 +1309,12 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
}
spin_unlock(&vfsmount_lock);
return 0;
+
+ out_cleanup_ids:
+ if (IS_MNT_SHARED(dest_mnt))
+ cleanup_group_ids(source_mnt, NULL);
+ out:
+ return err;
}
static int graft_tree(struct vfsmount *mnt, struct path *path)
@@ -1277,6 +1355,7 @@ static noinline int do_change_type(struct nameidata *nd, int flag)
struct vfsmount *m, *mnt = nd->path.mnt;
int recurse = flag & MS_REC;
int type = flag & ~MS_REC;
+ int err = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -1285,12 +1364,20 @@ static noinline int do_change_type(struct nameidata *nd, int flag)
return -EINVAL;
down_write(&namespace_sem);
+ if (type == MS_SHARED) {
+ err = invent_group_ids(mnt, recurse);
+ if (err)
+ goto out_unlock;
+ }
+
spin_lock(&vfsmount_lock);
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
spin_unlock(&vfsmount_lock);
+
+ out_unlock:
up_write(&namespace_sem);
- return 0;
+ return err;
}
/*
diff --git a/fs/pnode.c b/fs/pnode.c
index f968e35d978..d18d66491a0 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -46,7 +46,11 @@ static int do_make_slave(struct vfsmount *mnt)
if (peer_mnt == mnt)
peer_mnt = NULL;
}
+ if (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;
@@ -68,7 +72,6 @@ static int do_make_slave(struct vfsmount *mnt)
}
mnt->mnt_master = master;
CLEAR_MNT_SHARED(mnt);
- INIT_LIST_HEAD(&mnt->mnt_slave_list);
return 0;
}