Hi,
On 5/28/20 8:34 PM, Goffredo Baroncelli wrote:
> From: Goffredo Baroncelli <kreijack@xxxxxxxxx>
>
> Signed-off-by: Goffredo Baroncelli <kreijack@xxxxxxxxx>
>
> ---
> fs/btrfs/ioctl.c | 67 ++++++++++++++++++++++++++++++++++++++
> fs/btrfs/volumes.c | 2 +-
> fs/btrfs/volumes.h | 2 ++
> include/uapi/linux/btrfs.h | 40 +++++++++++++++++++++++
> 4 files changed, 110 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 40b729dce91c..cba3fa942e2f 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4724,6 +4724,71 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
> return ret;
> }
>
> +static long btrfs_ioctl_dev_properties(struct file *file,
> + void __user *argp)
> +{
> + struct inode *inode = file_inode(file);
> + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> + struct btrfs_ioctl_dev_properties dev_props;
> + struct btrfs_device *device;
> + struct btrfs_root *root = fs_info->chunk_root;
> + struct btrfs_trans_handle *trans;
FYI, the code contains a big mix of spaces and tabs to indent lines.
> + int ret;
> + u64 prev_type;
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + if (copy_from_user(&dev_props, argp, sizeof(dev_props)))
> + return -EFAULT;
> +
> + device = btrfs_find_device(fs_info->fs_devices, dev_props.devid,
> + NULL, NULL, false);
> + if (!device) {
> + btrfs_info(fs_info, "change_dev_properties: unable to find device %llu",
> + dev_props.devid);
> + return -ENODEV;
> + }
> +
> + if (dev_props.properties & BTRFS_DEV_PROPERTY_READ) {
> + u64 props = dev_props.properties;
> + memset(&dev_props, 0, sizeof(dev_props));
> + if (props & BTRFS_DEV_PROPERTY_TYPE) {
> + dev_props.properties = BTRFS_DEV_PROPERTY_TYPE;
> + dev_props.type = device->type;
> + }
> + if(copy_to_user(argp, &dev_props, sizeof(dev_props)))
> + return -EFAULT;
> + return 0;
> + }
> +
> + /* it is possible to set only BTRFS_DEV_PROPERTY_TYPE for now */
> + if (dev_props.properties & ~(BTRFS_DEV_PROPERTY_TYPE))
> + return -EPERM;
> +
> + trans = btrfs_start_transaction(root, 0);
> + if (IS_ERR(trans))
> + return PTR_ERR(trans);
> +
> + prev_type = device->type;
> + device->type = dev_props.type;
> + ret = btrfs_update_device(trans, device);
> +
> + if (ret < 0) {
> + btrfs_abort_transaction(trans, ret);
> + btrfs_end_transaction(trans);
> + device->type = prev_type;
> + return ret;
> + }
> +
> + ret = btrfs_commit_transaction(trans);
> + if (ret < 0)
> + device->type = prev_type;
> +
> + return ret;
> +
> +}
> +
> static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
> {
> struct btrfs_ioctl_send_args *arg;
> @@ -4907,6 +4972,8 @@ long btrfs_ioctl(struct file *file, unsigned int
> return btrfs_ioctl_get_subvol_rootref(file, argp);
> case BTRFS_IOC_INO_LOOKUP_USER:
> return btrfs_ioctl_ino_lookup_user(file, argp);
> + case BTRFS_IOC_DEV_PROPERTIES:
> + return btrfs_ioctl_dev_properties(file, argp);
> }
>
> return -ENOTTY;
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index be1e047a489e..5265f54c2931 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2710,7 +2710,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
> return ret;
> }
>
> -static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
> +int btrfs_update_device(struct btrfs_trans_handle *trans,
> struct btrfs_device *device)
> {
> int ret;
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index f067b5934c46..0ac5bf2b95e6 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -577,5 +577,7 @@ bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
> int btrfs_bg_type_to_factor(u64 flags);
> const char *btrfs_bg_type_to_raid_name(u64 flags);
> int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info);
> +int btrfs_update_device(struct btrfs_trans_handle *trans,
> + struct btrfs_device *device);
>
> #endif
> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> index e6b6cb0f8bc6..bb096075677d 100644
> --- a/include/uapi/linux/btrfs.h
> +++ b/include/uapi/linux/btrfs.h
> @@ -842,6 +842,44 @@ struct btrfs_ioctl_get_subvol_rootref_args {
> __u8 align[7];
> };
>
> +#define BTRFS_DEV_PROPERTY_TYPE (1ULL << 0)
> +#define BTRFS_DEV_PROPERTY_DEV_GROUP (1ULL << 1)
> +#define BTRFS_DEV_PROPERTY_SEEK_SPEED (1ULL << 2)
> +#define BTRFS_DEV_PROPERTY_BANDWIDTH (1ULL << 3)
> +#define BTRFS_DEV_PROPERTY_READ (1ULL << 60)
> +
> +/*
> + * The ioctl BTRFS_IOC_DEV_PROPERTIES can read and write the device properties.
> + *
> + * The properties that the user want to write have to be set
> + * in the 'properties' field using the BTRFS_DEV_PROPERTY_xxxx constants.
> + *
> + * If the ioctl is used to read the device properties, the bit
> + * BTRFS_DEV_PROPERTY_READ has to be set in the 'properties' field.
> + * In this case the properties that the user want have to be set in the
> + * 'properties' field. The kernel doesn't return a property that was not
> + * required, however it may return a subset of the requested properties.
> + * The returned properties have the corrispondent BTRFS_DEV_PROPERTY_xxxx
> + * flag set in the 'properties' field.
> + *
> + * Up to 2020/05/11 the only properties that can be read/write is the 'type'
> + * one.
> + */
> +struct btrfs_ioctl_dev_properties {
> + __u64 devid;
> + __u64 properties;
> + __u64 type;
> + __u32 dev_group;
> + __u8 seek_speed;
> + __u8 bandwidth;
> +
> + /*
> + * for future expansion
> + */
> + __u8 unused1[2];
> + __u64 unused2[4];
> +};
> +
> /* Error codes as returned by the kernel */
> enum btrfs_err_code {
> BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1,
> @@ -970,5 +1008,7 @@ enum btrfs_err_code {
> struct btrfs_ioctl_ino_lookup_user_args)
> #define BTRFS_IOC_SNAP_DESTROY_V2 _IOW(BTRFS_IOCTL_MAGIC, 63, \
> struct btrfs_ioctl_vol_args_v2)
> +#define BTRFS_IOC_DEV_PROPERTIES _IOW(BTRFS_IOCTL_MAGIC, 64, \
> + struct btrfs_ioctl_dev_properties)
>
> #endif /* _UAPI_LINUX_BTRFS_H */
>
