Re: [PATCH v2 6/7] btrfs: unify common code for the v1 and v2 versions of device remove

[Anand Jain <anand.jain@oracle.com>]

On 28/07/2021 05:01, Josef Bacik wrote:
> These things share a lot of common code, v2 simply allows you to specify
> devid.  Abstract out this common code and use the helper by both the v1
> and v2 interfaces to save us some lines of code.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>   fs/btrfs/ioctl.c | 99 +++++++++++++++++++-----------------------------
>   1 file changed, 38 insertions(+), 61 deletions(-)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index fabbfdfa56f5..e3a7e8544609 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3200,15 +3200,14 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
>   	return ret;
>   }
>   
> -static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
> +static long btrfs_do_device_removal(struct file *file, const char *path,
> +				    u64 devid, bool cancel)
>   {
>   	struct inode *inode = file_inode(file);
>   	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	struct btrfs_ioctl_vol_args_v2 *vol_args;
>   	struct block_device *bdev = NULL;
>   	fmode_t mode;
>   	int ret;
> -	bool cancel = false;
>   
>   	if (!capable(CAP_SYS_ADMIN))
>   		return -EPERM;
> @@ -3217,11 +3216,37 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
>   	if (ret)
>   		return ret;
>   
> -	vol_args = memdup_user(arg, sizeof(*vol_args));
> -	if (IS_ERR(vol_args)) {
> -		ret = PTR_ERR(vol_args);
> -		goto err_drop;
> +	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
> +					   cancel);
> +	if (ret)
> +		goto out;
> +
> +	/* Exclusive operation is now claimed */
> +	ret = btrfs_rm_device(fs_info, path, devid, &bdev, &mode);
> +	btrfs_exclop_finish(fs_info);
> +
> +	if (!ret) {
> +		if (path)
> +			btrfs_info(fs_info, "device deleted: %s", path);
> +		else
> +			btrfs_info(fs_info, "device deleted: id %llu", devid);
>   	}
> +out:
> +	mnt_drop_write_file(file);
> +	if (bdev)
> +		blkdev_put(bdev, mode);
> +	return ret;
> +}
> +
> +static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
> +{
> +	struct btrfs_ioctl_vol_args_v2 *vol_args;
> +	int ret = 0;
> +	bool cancel = false;
> +
> +	vol_args = memdup_user(arg, sizeof(*vol_args));
> +	if (IS_ERR(vol_args))
> +		return PTR_ERR(vol_args);
>   
>   	if (vol_args->flags & ~BTRFS_DEVICE_REMOVE_ARGS_MASK) {
>   		ret = -EOPNOTSUPP;
> @@ -3232,79 +3257,31 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
>   	    strcmp("cancel", vol_args->name) == 0)
>   		cancel = true;
>   
> -	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
> -					   cancel);
> -	if (ret)
> -		goto out;
> -	/* Exclusive operation is now claimed */
> -
>   	if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
> -		ret = btrfs_rm_device(fs_info, NULL, vol_args->devid, &bdev,
> -				      &mode);
> +		ret = btrfs_do_device_removal(file, NULL, vol_args->devid,
> +					      cancel);
>   	else
> -		ret = btrfs_rm_device(fs_info, vol_args->name, 0, &bdev,
> -				      &mode);
> -
> -	btrfs_exclop_finish(fs_info);
> -
> -	if (!ret) {
> -		if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
> -			btrfs_info(fs_info, "device deleted: id %llu",
> -					vol_args->devid);
> -		else
> -			btrfs_info(fs_info, "device deleted: %s",
> -					vol_args->name);
> -	}
> +		ret = btrfs_do_device_removal(file, vol_args->name, 0, cancel);
>   out:
>   	kfree(vol_args);
> -err_drop:
> -	mnt_drop_write_file(file);
> -	if (bdev)
> -		blkdev_put(bdev, mode);
>   	return ret;
>   }
>   
>   static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
>   {
> -	struct inode *inode = file_inode(file);
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
>   	struct btrfs_ioctl_vol_args *vol_args;
> -	struct block_device *bdev = NULL;
> -	fmode_t mode;
>   	int ret;
>   	bool cancel;
>   
> -	if (!capable(CAP_SYS_ADMIN))
> -		return -EPERM;
> -
> -	ret = mnt_want_write_file(file);
> -	if (ret)
> -		return ret;
> -
>   	vol_args = memdup_user(arg, sizeof(*vol_args));
> -	if (IS_ERR(vol_args)) {
> -		ret = PTR_ERR(vol_args);
> -		goto out_drop_write;
> -	}
> +	if (IS_ERR(vol_args))
> +		return PTR_ERR(vol_args);
>   	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
>   	cancel = (strcmp("cancel", vol_args->name) == 0);
>   
> -	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_DEV_REMOVE,
> -					   cancel);
> -	if (ret == 0) {
> -		ret = btrfs_rm_device(fs_info, vol_args->name, 0, &bdev,
> -				      &mode);
> -		if (!ret)
> -			btrfs_info(fs_info, "disk deleted %s", vol_args->name);
> -		btrfs_exclop_finish(fs_info);
> -	}
> +	ret = btrfs_do_device_removal(file, vol_args->name, 0, cancel);
>   
>   	kfree(vol_args);
> -out_drop_write:
> -	mnt_drop_write_file(file);
> -
> -	if (bdev)
> -		blkdev_put(bdev, mode);
>   	return ret;
>   }
>   
> 


Looks much better now.

Reviewed-by: Anand Jain <anand.jain@oracle.com>

Thanks.