Driver: spi: fix compiling err for rk3288

[firefly-linux-kernel-4.4.55.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 7df3d406d3e00f8e96060193df1c48aed53ed848..a22959c973842fd6d964a5429ad4707f0fe263a5 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -27,6 +27,9 @@
 #include "pnode.h"
 #include "internal.h"
 
+/* Maximum number of mounts in a mount namespace */
+unsigned int sysctl_mount_max __read_mostly = 100000;
+
 static unsigned int m_hash_mask __read_mostly;
 static unsigned int m_hash_shift __read_mostly;
 static unsigned int mp_hash_mask __read_mostly;
@@ -577,6 +580,7 @@ int sb_prepare_remount_readonly(struct super_block *sb)
 
 static void free_vfsmnt(struct mount *mnt)
 {
+       kfree(mnt->mnt.data);
        kfree_const(mnt->mnt_devname);
 #ifdef CONFIG_SMP
        free_percpu(mnt->mnt_pcp);
@@ -925,6 +929,9 @@ static void commit_tree(struct mount *mnt)
 
        list_splice(&head, n->list.prev);
 
+       n->mounts += n->pending_mounts;
+       n->pending_mounts = 0;
+
        __attach_mnt(mnt, parent);
        touch_mnt_namespace(n);
 }
@@ -968,11 +975,21 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
        if (!mnt)
                return ERR_PTR(-ENOMEM);
 
+       mnt->mnt.data = NULL;
+       if (type->alloc_mnt_data) {
+               mnt->mnt.data = type->alloc_mnt_data();
+               if (!mnt->mnt.data) {
+                       mnt_free_id(mnt);
+                       free_vfsmnt(mnt);
+                       return ERR_PTR(-ENOMEM);
+               }
+       }
        if (flags & MS_KERNMOUNT)
                mnt->mnt.mnt_flags = MNT_INTERNAL;
 
-       root = mount_fs(type, flags, name, data);
+       root = mount_fs(type, flags, name, &mnt->mnt, data);
        if (IS_ERR(root)) {
+               kfree(mnt->mnt.data);
                mnt_free_id(mnt);
                free_vfsmnt(mnt);
                return ERR_CAST(root);
@@ -1000,6 +1017,14 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
        if (!mnt)
                return ERR_PTR(-ENOMEM);
 
+       if (sb->s_op->clone_mnt_data) {
+               mnt->mnt.data = sb->s_op->clone_mnt_data(old->mnt.data);
+               if (!mnt->mnt.data) {
+                       err = -ENOMEM;
+                       goto out_free;
+               }
+       }
+
        if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE))
                mnt->mnt_group_id = 0; /* not a peer of original */
        else
@@ -1068,6 +1093,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
        return mnt;
 
  out_free:
+       kfree(mnt->mnt.data);
        mnt_free_id(mnt);
        free_vfsmnt(mnt);
        return ERR_PTR(err);
@@ -1445,11 +1471,16 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
                propagate_umount(&tmp_list);
 
        while (!list_empty(&tmp_list)) {
+               struct mnt_namespace *ns;
                bool disconnect;
                p = list_first_entry(&tmp_list, struct mount, mnt_list);
                list_del_init(&p->mnt_expire);
                list_del_init(&p->mnt_list);
-               __touch_mnt_namespace(p->mnt_ns);
+               ns = p->mnt_ns;
+               if (ns) {
+                       ns->mounts--;
+                       __touch_mnt_namespace(ns);
+               }
                p->mnt_ns = NULL;
                if (how & UMOUNT_SYNC)
                        p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
@@ -1850,6 +1881,28 @@ static int invent_group_ids(struct mount *mnt, bool recurse)
        return 0;
 }
 
+int count_mounts(struct mnt_namespace *ns, struct mount *mnt)
+{
+       unsigned int max = READ_ONCE(sysctl_mount_max);
+       unsigned int mounts = 0, old, pending, sum;
+       struct mount *p;
+
+       for (p = mnt; p; p = next_mnt(p, mnt))
+               mounts++;
+
+       old = ns->mounts;
+       pending = ns->pending_mounts;
+       sum = old + pending;
+       if ((old > sum) ||
+           (pending > sum) ||
+           (max < sum) ||
+           (mounts > (max - sum)))
+               return -ENOSPC;
+
+       ns->pending_mounts = pending + mounts;
+       return 0;
+}
+
 /*
  *  @source_mnt : mount tree to be attached
  *  @nd         : place the mount tree @source_mnt is attached
@@ -1919,6 +1972,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
                        struct path *parent_path)
 {
        HLIST_HEAD(tree_list);
+       struct mnt_namespace *ns = dest_mnt->mnt_ns;
        struct mountpoint *smp;
        struct mount *child, *p;
        struct hlist_node *n;
@@ -1931,6 +1985,13 @@ static int attach_recursive_mnt(struct mount *source_mnt,
        if (IS_ERR(smp))
                return PTR_ERR(smp);
 
+       /* Is there space to add these mounts to the mount namespace? */
+       if (!parent_path) {
+               err = count_mounts(ns, source_mnt);
+               if (err)
+                       goto out;
+       }
+
        if (IS_MNT_SHARED(dest_mnt)) {
                err = invent_group_ids(source_mnt, true);
                if (err)
@@ -1970,11 +2031,14 @@ static int attach_recursive_mnt(struct mount *source_mnt,
  out_cleanup_ids:
        while (!hlist_empty(&tree_list)) {
                child = hlist_entry(tree_list.first, struct mount, mnt_hash);
+               child->mnt_parent->mnt_ns->pending_mounts = 0;
                umount_tree(child, UMOUNT_SYNC);
        }
        unlock_mount_hash();
        cleanup_group_ids(source_mnt, NULL);
  out:
+       ns->pending_mounts = 0;
+
        read_seqlock_excl(&mount_lock);
        put_mountpoint(smp);
        read_sequnlock_excl(&mount_lock);
@@ -2243,8 +2307,14 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
                err = change_mount_flags(path->mnt, flags);
        else if (!capable(CAP_SYS_ADMIN))
                err = -EPERM;
-       else
-               err = do_remount_sb(sb, flags, data, 0);
+       else {
+               err = do_remount_sb2(path->mnt, sb, flags, data, 0);
+               namespace_lock();
+               lock_mount_hash();
+               propagate_remount(mnt);
+               unlock_mount_hash();
+               namespace_unlock();
+       }
        if (!err) {
                lock_mount_hash();
                mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
@@ -2804,6 +2874,8 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns)
        init_waitqueue_head(&new_ns->poll);
        new_ns->event = 0;
        new_ns->user_ns = get_user_ns(user_ns);
+       new_ns->mounts = 0;
+       new_ns->pending_mounts = 0;
        return new_ns;
 }
 
@@ -2853,6 +2925,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
        q = new;
        while (p) {
                q->mnt_ns = new_ns;
+               new_ns->mounts++;
                if (new_fs) {
                        if (&p->mnt == new_fs->root.mnt) {
                                new_fs->root.mnt = mntget(&q->mnt);
@@ -2891,6 +2964,7 @@ static struct mnt_namespace *create_mnt_ns(struct vfsmount *m)
                struct mount *mnt = real_mount(m);
                mnt->mnt_ns = new_ns;
                new_ns->root = mnt;
+               new_ns->mounts++;
                list_add(&mnt->mnt_list, &new_ns->list);
        } else {
                mntput(m);