#include <linux/mount.h>
#include <linux/ramfs.h>
#include <linux/log2.h>
+#include <linux/idr.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
__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;
#define MNT_WRITER_UNDERFLOW_LIMIT -(1<<16)
+/* allocation is serialized by namespace_sem */
+static int mnt_alloc_id(struct vfsmount *mnt)
+{
+ int res;
+
+retry:
+ ida_pre_get(&mnt_id_ida, GFP_KERNEL);
+ spin_lock(&vfsmount_lock);
+ res = ida_get_new(&mnt_id_ida, &mnt->mnt_id);
+ spin_unlock(&vfsmount_lock);
+ if (res == -EAGAIN)
+ goto retry;
+
+ return res;
+}
+
+static void mnt_free_id(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ ida_remove(&mnt_id_ida, mnt->mnt_id);
+ 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);
if (mnt) {
+ int err;
+
+ err = mnt_alloc_id(mnt);
+ if (err) {
+ kmem_cache_free(mnt_cache, mnt);
+ return NULL;
+ }
+
atomic_set(&mnt->mnt_count, 1);
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
void free_vfsmnt(struct vfsmount *mnt)
{
kfree(mnt->mnt_devname);
+ mnt_free_id(mnt);
kmem_cache_free(mnt_cache, mnt);
}
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;
}
}
return mnt;
+
+ out_free:
+ free_vfsmnt(mnt);
+ return NULL;
}
static inline void __mntput(struct vfsmount *mnt)
}
EXPORT_SYMBOL(save_mount_options);
+#ifdef CONFIG_PROC_FS
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
{
- struct mnt_namespace *n = m->private;
+ struct proc_mounts *p = m->private;
down_read(&namespace_sem);
- return seq_list_start(&n->list, *pos);
+ return seq_list_start(&p->ns->list, *pos);
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
- struct mnt_namespace *n = m->private;
+ struct proc_mounts *p = m->private;
- return seq_list_next(v, &n->list, pos);
+ return seq_list_next(v, &p->ns->list, pos);
}
static void m_stop(struct seq_file *m, void *v)
return err;
}
-struct seq_operations mounts_op = {
+const struct seq_operations mounts_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
return err;
}
-struct seq_operations mountstats_op = {
+const struct seq_operations mountstats_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_vfsstat,
};
+#endif /* CONFIG_PROC_FS */
/**
* may_umount_tree - check if a mount tree is busy
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
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))
}
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 nameidata *nd)
+static int graft_tree(struct vfsmount *mnt, struct path *path)
{
int err;
if (mnt->mnt_sb->s_flags & MS_NOUSER)
return -EINVAL;
- if (S_ISDIR(nd->path.dentry->d_inode->i_mode) !=
+ if (S_ISDIR(path->dentry->d_inode->i_mode) !=
S_ISDIR(mnt->mnt_root->d_inode->i_mode))
return -ENOTDIR;
err = -ENOENT;
- mutex_lock(&nd->path.dentry->d_inode->i_mutex);
- if (IS_DEADDIR(nd->path.dentry->d_inode))
+ mutex_lock(&path->dentry->d_inode->i_mutex);
+ if (IS_DEADDIR(path->dentry->d_inode))
goto out_unlock;
- err = security_sb_check_sb(mnt, &nd->path);
+ err = security_sb_check_sb(mnt, path);
if (err)
goto out_unlock;
err = -ENOENT;
- if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))
- err = attach_recursive_mnt(mnt, &nd->path, NULL);
+ if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry))
+ err = attach_recursive_mnt(mnt, path, NULL);
out_unlock:
- mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
if (!err)
- security_sb_post_addmount(mnt, &nd->path);
+ security_sb_post_addmount(mnt, path);
return err;
}
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;
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;
}
/*
if (!mnt)
goto out;
- err = graft_tree(mnt, nd);
+ err = graft_tree(mnt, &nd->path);
if (err) {
LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
goto unlock;
newmnt->mnt_flags = mnt_flags;
- if ((err = graft_tree(newmnt, nd)))
+ if ((err = graft_tree(newmnt, &nd->path)))
goto unlock;
if (fslist) /* add to the specified expiration list */
const char __user * put_old)
{
struct vfsmount *tmp;
- struct nameidata new_nd, old_nd, user_nd;
- struct path parent_path, root_parent;
+ struct nameidata new_nd, old_nd;
+ struct path parent_path, root_parent, root;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- lock_kernel();
-
error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
&new_nd);
if (error)
}
read_lock(¤t->fs->lock);
- user_nd.path = current->fs->root;
+ root = current->fs->root;
path_get(¤t->fs->root);
read_unlock(¤t->fs->lock);
down_write(&namespace_sem);
error = -EINVAL;
if (IS_MNT_SHARED(old_nd.path.mnt) ||
IS_MNT_SHARED(new_nd.path.mnt->mnt_parent) ||
- IS_MNT_SHARED(user_nd.path.mnt->mnt_parent))
+ IS_MNT_SHARED(root.mnt->mnt_parent))
goto out2;
- if (!check_mnt(user_nd.path.mnt))
+ if (!check_mnt(root.mnt))
goto out2;
error = -ENOENT;
if (IS_DEADDIR(new_nd.path.dentry->d_inode))
if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry))
goto out2;
error = -EBUSY;
- if (new_nd.path.mnt == user_nd.path.mnt ||
- old_nd.path.mnt == user_nd.path.mnt)
+ if (new_nd.path.mnt == root.mnt ||
+ old_nd.path.mnt == root.mnt)
goto out2; /* loop, on the same file system */
error = -EINVAL;
- if (user_nd.path.mnt->mnt_root != user_nd.path.dentry)
+ if (root.mnt->mnt_root != root.dentry)
goto out2; /* not a mountpoint */
- if (user_nd.path.mnt->mnt_parent == user_nd.path.mnt)
+ if (root.mnt->mnt_parent == root.mnt)
goto out2; /* not attached */
if (new_nd.path.mnt->mnt_root != new_nd.path.dentry)
goto out2; /* not a mountpoint */
} else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
goto out3;
detach_mnt(new_nd.path.mnt, &parent_path);
- detach_mnt(user_nd.path.mnt, &root_parent);
+ detach_mnt(root.mnt, &root_parent);
/* mount old root on put_old */
- attach_mnt(user_nd.path.mnt, &old_nd.path);
+ attach_mnt(root.mnt, &old_nd.path);
/* mount new_root on / */
attach_mnt(new_nd.path.mnt, &root_parent);
touch_mnt_namespace(current->nsproxy->mnt_ns);
spin_unlock(&vfsmount_lock);
- chroot_fs_refs(&user_nd.path, &new_nd.path);
- security_sb_post_pivotroot(&user_nd.path, &new_nd.path);
+ chroot_fs_refs(&root, &new_nd.path);
+ security_sb_post_pivotroot(&root, &new_nd.path);
error = 0;
path_put(&root_parent);
path_put(&parent_path);
out2:
mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
up_write(&namespace_sem);
- path_put(&user_nd.path);
+ path_put(&root);
path_put(&old_nd.path);
out1:
path_put(&new_nd.path);
out0:
- unlock_kernel();
return error;
out3:
spin_unlock(&vfsmount_lock);
projects / linux-2.6-omap-h63xx.git / blobdiff