1 files changed, 65 insertions, 56 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 7313c62e3e9..c5e412a00b1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -502,17 +502,14 @@ static const struct inode_operations proc_def_inode_operations = {
 	.setattr	= proc_setattr,
 };
 
-extern const struct seq_operations mounts_op;
-struct proc_mounts {
-	struct seq_file m;
-	int event;
-};
-
-static int mounts_open(struct inode *inode, struct file *file)
+static int mounts_open_common(struct inode *inode, struct file *file,
+			      const struct seq_operations *op)
 {
 	struct task_struct *task = get_proc_task(inode);
 	struct nsproxy *nsp;
 	struct mnt_namespace *ns = NULL;
+	struct fs_struct *fs = NULL;
+	struct path root;
 	struct proc_mounts *p;
 	int ret = -EINVAL;
 
@@ -525,40 +522,61 @@ static int mounts_open(struct inode *inode, struct file *file)
 				get_mnt_ns(ns);
 		}
 		rcu_read_unlock();
-
+		if (ns)
+			fs = get_fs_struct(task);
 		put_task_struct(task);
 	}
 
-	if (ns) {
-		ret = -ENOMEM;
-		p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
-		if (p) {
-			file->private_data = &p->m;
-			ret = seq_open(file, &mounts_op);
-			if (!ret) {
-				p->m.private = ns;
-				p->event = ns->event;
-				return 0;
-			}
-			kfree(p);
-		}
-		put_mnt_ns(ns);
-	}
+	if (!ns)
+		goto err;
+	if (!fs)
+		goto err_put_ns;
+
+	read_lock(&fs->lock);
+	root = fs->root;
+	path_get(&root);
+	read_unlock(&fs->lock);
+	put_fs_struct(fs);
+
+	ret = -ENOMEM;
+	p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
+	if (!p)
+		goto err_put_path;
+
+	file->private_data = &p->m;
+	ret = seq_open(file, op);
+	if (ret)
+		goto err_free;
+
+	p->m.private = p;
+	p->ns = ns;
+	p->root = root;
+	p->event = ns->event;
+
+	return 0;
+
+ err_free:
+	kfree(p);
+ err_put_path:
+	path_put(&root);
+ err_put_ns:
+	put_mnt_ns(ns);
+ err:
 	return ret;
 }
 
 static int mounts_release(struct inode *inode, struct file *file)
 {
-	struct seq_file *m = file->private_data;
-	struct mnt_namespace *ns = m->private;
-	put_mnt_ns(ns);
+	struct proc_mounts *p = file->private_data;
+	path_put(&p->root);
+	put_mnt_ns(p->ns);
 	return seq_release(inode, file);
 }
 
 static unsigned mounts_poll(struct file *file, poll_table *wait)
 {
 	struct proc_mounts *p = file->private_data;
-	struct mnt_namespace *ns = p->m.private;
+	struct mnt_namespace *ns = p->ns;
 	unsigned res = 0;
 
 	poll_wait(file, &ns->poll, wait);
@@ -573,6 +591,11 @@ static unsigned mounts_poll(struct file *file, poll_table *wait)
 	return res;
 }
 
+static int mounts_open(struct inode *inode, struct file *file)
+{
+	return mounts_open_common(inode, file, &mounts_op);
+}
+
 static const struct file_operations proc_mounts_operations = {
 	.open		= mounts_open,
 	.read		= seq_read,
@@ -581,38 +604,22 @@ static const struct file_operations proc_mounts_operations = {
 	.poll		= mounts_poll,
 };
 
-extern const struct seq_operations mountstats_op;
-static int mountstats_open(struct inode *inode, struct file *file)
+static int mountinfo_open(struct inode *inode, struct file *file)
 {
-	int ret = seq_open(file, &mountstats_op);
-
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-		struct nsproxy *nsp;
-		struct mnt_namespace *mnt_ns = NULL;
-		struct task_struct *task = get_proc_task(inode);
-
-		if (task) {
-			rcu_read_lock();
-			nsp = task_nsproxy(task);
-			if (nsp) {
-				mnt_ns = nsp->mnt_ns;
-				if (mnt_ns)
-					get_mnt_ns(mnt_ns);
-			}
-			rcu_read_unlock();
+	return mounts_open_common(inode, file, &mountinfo_op);
+}
 
-			put_task_struct(task);
-		}
+static const struct file_operations proc_mountinfo_operations = {
+	.open		= mountinfo_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= mounts_release,
+	.poll		= mounts_poll,
+};
 
-		if (mnt_ns)
-			m->private = mnt_ns;
-		else {
-			seq_release(inode, file);
-			ret = -EINVAL;
-		}
-	}
-	return ret;
+static int mountstats_open(struct inode *inode, struct file *file)
+{
+	return mounts_open_common(inode, file, &mountstats_op);
 }
 
 static const struct file_operations proc_mountstats_operations = {
@@ -2309,6 +2316,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 	LNK("root",       root),
 	LNK("exe",        exe),
 	REG("mounts",     S_IRUGO, mounts),
+	REG("mountinfo",  S_IRUGO, mountinfo),
 	REG("mountstats", S_IRUSR, mountstats),
 #ifdef CONFIG_PROC_PAGE_MONITOR
 	REG("clear_refs", S_IWUSR, clear_refs),
@@ -2641,6 +2649,7 @@ static const struct pid_entry tid_base_stuff[] = {
 	LNK("root",      root),
 	LNK("exe",       exe),
 	REG("mounts",    S_IRUGO, mounts),
+	REG("mountinfo",  S_IRUGO, mountinfo),
 #ifdef CONFIG_PROC_PAGE_MONITOR
 	REG("clear_refs", S_IWUSR, clear_refs),
 	REG("smaps",     S_IRUGO, smaps),