Commit 9ba1f6e4 authored by Liu Bo's avatar Liu Bo Committed by Josef Bacik
Browse files

Btrfs: do not do balance in readonly mode 



In normal cases, we would not be allowed to do balance in RO mode.
However, when we're using a seeding device and adding another device to sprout,
things will change:

$ mkfs.btrfs /dev/sdb7
$ btrfstune -S 1 /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs -o ro
$ btrfs fi bal /mnt/btrfs   -----------------------> fail.
$ btrfs dev add /dev/sdb8 /mnt/btrfs
$ btrfs fi bal /mnt/btrfs   -----------------------> works!

It should not be designed as an exception, and we'd better add another check for
mnt flags.

Signed-off-by: default avatarLiu Bo <liubo2009@cn.fujitsu.com>
Reviewed-by: default avatarJosef Bacik <josef@redhat.com>
parent d1ac6e41

fs/btrfs/ioctl.c

+9 −3
Original line number Diff line number Diff line
@@ -3216,8 +3216,9 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock, 
	}

}



static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg)

static long btrfs_ioctl_balance(struct file *file, void __user *arg)

{

	struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct btrfs_ioctl_balance_args *bargs;

	struct btrfs_balance_control *bctl;
@@ -3229,6 +3230,10 @@ static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg) 
	if (fs_info->sb->s_flags & MS_RDONLY)

		return -EROFS;



	ret = mnt_want_write(file->f_path.mnt);

	if (ret)

		return ret;



	mutex_lock(&fs_info->volume_mutex);

	mutex_lock(&fs_info->balance_mutex);
@@ -3295,6 +3300,7 @@ out_bargs: 
out:

	mutex_unlock(&fs_info->balance_mutex);

	mutex_unlock(&fs_info->volume_mutex);

	mnt_drop_write(file->f_path.mnt);

	return ret;

}
@@ -3390,7 +3396,7 @@ long btrfs_ioctl(struct file *file, unsigned int 
	case BTRFS_IOC_DEV_INFO:

		return btrfs_ioctl_dev_info(root, argp);

	case BTRFS_IOC_BALANCE:

		return btrfs_ioctl_balance(root, NULL);

		return btrfs_ioctl_balance(file, NULL);

	case BTRFS_IOC_CLONE:

		return btrfs_ioctl_clone(file, arg, 0, 0, 0);

	case BTRFS_IOC_CLONE_RANGE:
@@ -3423,7 +3429,7 @@ long btrfs_ioctl(struct file *file, unsigned int 
	case BTRFS_IOC_SCRUB_PROGRESS:

		return btrfs_ioctl_scrub_progress(root, argp);

	case BTRFS_IOC_BALANCE_V2:

		return btrfs_ioctl_balance(root, argp);

		return btrfs_ioctl_balance(file, argp);

	case BTRFS_IOC_BALANCE_CTL:

		return btrfs_ioctl_balance_ctl(root, arg);

	case BTRFS_IOC_BALANCE_PROGRESS:

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