1 files changed, 38 insertions, 57 deletions

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 093551fe66a7..c4f6d65596cf 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -599,8 +599,7 @@ static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
 	dir->i_size += DIRENT_SIZE;
 	simple_inode_init_ts(dir);
 
-	d_instantiate(dentry, inode);
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 	return 0;
 out_unlock:
 	spin_unlock(&mq_lock);
@@ -617,13 +616,8 @@ static int mqueue_create(struct mnt_idmap *idmap, struct inode *dir,
 
 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 {
-	struct inode *inode = d_inode(dentry);
-
-	simple_inode_init_ts(dir);
 	dir->i_size -= DIRENT_SIZE;
-	drop_nlink(inode);
-	dput(dentry);
-	return 0;
+	return simple_unlink(dir, dentry);
 }
 
 /*
@@ -892,15 +886,35 @@ static int prepare_open(struct dentry *dentry, int oflag, int ro,
 	return inode_permission(&nop_mnt_idmap, d_inode(dentry), acc);
 }
 
+static struct file *mqueue_file_open(struct filename *name,
+				     struct vfsmount *mnt, int oflag, int ro,
+				     umode_t mode, struct mq_attr *attr)
+{
+	struct dentry *dentry;
+	struct file *file;
+	int ret;
+
+	dentry = start_creating_noperm(mnt->mnt_root, &QSTR(name->name));
+	if (IS_ERR(dentry))
+		return ERR_CAST(dentry);
+
+	ret = prepare_open(dentry, oflag, ro, mode, name, attr);
+	file = ERR_PTR(ret);
+	if (!ret) {
+		const struct path path = { .mnt = mnt, .dentry = dentry };
+		file = dentry_open(&path, oflag, current_cred());
+	}
+
+	end_creating(dentry);
+	return file;
+}
+
 static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
 		      struct mq_attr *attr)
 {
+	struct filename *name __free(putname) = NULL;;
 	struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
-	struct dentry *root = mnt->mnt_root;
-	struct filename *name;
-	struct path path;
-	int fd, error;
-	int ro;
+	int fd, ro;
 
 	audit_mq_open(oflag, mode, attr);
 
@@ -908,37 +922,10 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
-	fd = get_unused_fd_flags(O_CLOEXEC);
-	if (fd < 0)
-		goto out_putname;
-
 	ro = mnt_want_write(mnt);	/* we'll drop it in any case */
-	inode_lock(d_inode(root));
-	path.dentry = lookup_noperm(&QSTR(name->name), root);
-	if (IS_ERR(path.dentry)) {
-		error = PTR_ERR(path.dentry);
-		goto out_putfd;
-	}
-	path.mnt = mntget(mnt);
-	error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
-	if (!error) {
-		struct file *file = dentry_open(&path, oflag, current_cred());
-		if (!IS_ERR(file))
-			fd_install(fd, file);
-		else
-			error = PTR_ERR(file);
-	}
-	path_put(&path);
-out_putfd:
-	if (error) {
-		put_unused_fd(fd);
-		fd = error;
-	}
-	inode_unlock(d_inode(root));
+	fd = FD_ADD(O_CLOEXEC, mqueue_file_open(name, mnt, oflag, ro, mode, attr));
 	if (!ro)
 		mnt_drop_write(mnt);
-out_putname:
-	putname(name);
 	return fd;
 }
 
@@ -957,7 +944,7 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 	int err;
 	struct filename *name;
 	struct dentry *dentry;
-	struct inode *inode = NULL;
+	struct inode *inode;
 	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 	struct vfsmount *mnt = ipc_ns->mq_mnt;
 
@@ -969,26 +956,20 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 	err = mnt_want_write(mnt);
 	if (err)
 		goto out_name;
-	inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
-	dentry = lookup_noperm(&QSTR(name->name), mnt->mnt_root);
+	dentry = start_removing_noperm(mnt->mnt_root, &QSTR(name->name));
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
-		goto out_unlock;
+		goto out_drop_write;
 	}
 
 	inode = d_inode(dentry);
-	if (!inode) {
-		err = -ENOENT;
-	} else {
-		ihold(inode);
-		err = vfs_unlink(&nop_mnt_idmap, d_inode(dentry->d_parent),
-				 dentry, NULL);
-	}
-	dput(dentry);
-
-out_unlock:
-	inode_unlock(d_inode(mnt->mnt_root));
+	ihold(inode);
+	err = vfs_unlink(&nop_mnt_idmap, d_inode(mnt->mnt_root),
+			 dentry, NULL);
+	end_removing(dentry);
 	iput(inode);
+
+out_drop_write:
 	mnt_drop_write(mnt);
 out_name:
 	putname(name);
@@ -1638,7 +1619,7 @@ static const struct fs_context_operations mqueue_fs_context_ops = {
 static struct file_system_type mqueue_fs_type = {
 	.name			= "mqueue",
 	.init_fs_context	= mqueue_init_fs_context,
-	.kill_sb		= kill_litter_super,
+	.kill_sb		= kill_anon_super,
 	.fs_flags		= FS_USERNS_MOUNT,
 };