btrfs: Remove userspace transaction ioctls

Commit 3558d4f88ec8 ("btrfs: Deprecate userspace transaction ioctls")
marked the beginning of the end of userspace transaction. This commit
finishes the job! There are no known users and ceph does not use the
ioctl anymore.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Acked-by: Sage Weil <sage@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -3207,7 +3207,6 @@ void btrfs_destroy_inode(struct inode *inode);
 int btrfs_drop_inode(struct inode *inode);
 int __init btrfs_init_cachep(void);
 void __cold btrfs_destroy_cachep(void);
-long btrfs_ioctl_trans_end(struct file *file);
 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
 			 struct btrfs_root *root, int *was_new);
 struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,

fs/btrfs/file.c

@@ -1997,8 +1997,6 @@ int btrfs_release_file(struct inode *inode, struct file *filp)
 {
 	struct btrfs_file_private *private = filp->private_data;
 
-	if (private && private->trans)
-		btrfs_ioctl_trans_end(filp);
 	if (private && private->filldir_buf)
 		kfree(private->filldir_buf);
 	kfree(private);
@@ -2189,12 +2187,6 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		goto out;
 	}
 
-	/*
-	 * ok we haven't committed the transaction yet, lets do a commit
-	 */
-	if (file->private_data)
-		btrfs_ioctl_trans_end(file);
-
 	/*
 	 * We use start here because we will need to wait on the IO to complete
 	 * in btrfs_sync_log, which could require joining a transaction (for

fs/btrfs/ioctl.c

@@ -3936,73 +3936,6 @@ int btrfs_clone_file_range(struct file *src_file, loff_t off,
 	return btrfs_clone_files(dst_file, src_file, off, len, destoff);
 }
 
-/*
- * there are many ways the trans_start and trans_end ioctls can lead
- * to deadlocks.  They should only be used by applications that
- * basically own the machine, and have a very in depth understanding
- * of all the possible deadlocks and enospc problems.
- */
-static long btrfs_ioctl_trans_start(struct file *file)
-{
-	struct inode *inode = file_inode(file);
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
-	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct btrfs_trans_handle *trans;
-	struct btrfs_file_private *private;
-	int ret;
-	static bool warned = false;
-
-	ret = -EPERM;
-	if (!capable(CAP_SYS_ADMIN))
-		goto out;
-
-	if (!warned) {
-		btrfs_warn(fs_info,
-			"Userspace transaction mechanism is considered "
-			"deprecated and slated to be removed in 4.17. "
-			"If you have a valid use case please "
-			"speak up on the mailing list");
-		WARN_ON(1);
-		warned = true;
-	}
-
-	ret = -EINPROGRESS;
-	private = file->private_data;
-	if (private && private->trans)
-		goto out;
-	if (!private) {
-		private = kzalloc(sizeof(struct btrfs_file_private),
-				  GFP_KERNEL);
-		if (!private)
-			return -ENOMEM;
-		file->private_data = private;
-	}
-
-	ret = -EROFS;
-	if (btrfs_root_readonly(root))
-		goto out;
-
-	ret = mnt_want_write_file(file);
-	if (ret)
-		goto out;
-
-	atomic_inc(&fs_info->open_ioctl_trans);
-
-	ret = -ENOMEM;
-	trans = btrfs_start_ioctl_transaction(root);
-	if (IS_ERR(trans))
-		goto out_drop;
-
-	private->trans = trans;
-	return 0;
-
-out_drop:
-	atomic_dec(&fs_info->open_ioctl_trans);
-	mnt_drop_write_file(file);
-out:
-	return ret;
-}
-
 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
 {
 	struct inode *inode = file_inode(file);
@@ -4244,30 +4177,6 @@ out:
 	return ret;
 }
 
-/*
- * there are many ways the trans_start and trans_end ioctls can lead
- * to deadlocks.  They should only be used by applications that
- * basically own the machine, and have a very in depth understanding
- * of all the possible deadlocks and enospc problems.
- */
-long btrfs_ioctl_trans_end(struct file *file)
-{
-	struct inode *inode = file_inode(file);
-	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct btrfs_file_private *private = file->private_data;
-
-	if (!private || !private->trans)
-		return -EINVAL;
-
-	btrfs_end_transaction(private->trans);
-	private->trans = NULL;
-
-	atomic_dec(&root->fs_info->open_ioctl_trans);
-
-	mnt_drop_write_file(file);
-	return 0;
-}
-
 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
 					    void __user *argp)
 {
@@ -5575,10 +5484,6 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return btrfs_ioctl_dev_info(fs_info, argp);
 	case BTRFS_IOC_BALANCE:
 		return btrfs_ioctl_balance(file, NULL);
-	case BTRFS_IOC_TRANS_START:
-		return btrfs_ioctl_trans_start(file);
-	case BTRFS_IOC_TRANS_END:
-		return btrfs_ioctl_trans_end(file);
 	case BTRFS_IOC_TREE_SEARCH:
 		return btrfs_ioctl_tree_search(file, argp);
 	case BTRFS_IOC_TREE_SEARCH_V2: