On 12.07.2018 09:23, Gu Jinxiang wrote:
> Instead of pointer to btrfs_fs_devices as an arg in
> btrfs_scan_one_device, better to make it as a return value.
>
> And since btrfs_fs_devices can be get by btrfs_device,
> better to return btrfs_device than fs_btrfs_devices.
>
> Signed-off-by: Gu Jinxiang <g...@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nbori...@suse.com>
> ---
>
> Changelog:
> v4: as suggested by Anand, change return value of
> btrfs_scan_one_device from btrfs_fs_devices to btrfs_device.
> v3: as comment by robot, use PTR_ERR_OR_ZERO, and rebase to misc-next.
> v2: as comment by Nikolay, use ERR_CAST instead of cast type manually.
>
> fs/btrfs/super.c | 37 ++++++++++++++++++++++++-------------
> fs/btrfs/volumes.c | 17 ++++++-----------
> fs/btrfs/volumes.h | 4 ++--
> 3 files changed, 32 insertions(+), 26 deletions(-)
>
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 44f58bdb5fa6..e73d547eacff 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -888,7 +888,7 @@ static int btrfs_parse_early_options(const char *options,
> fmode_t flags,
> {
> substring_t args[MAX_OPT_ARGS];
> char *device_name, *opts, *orig, *p;
> - struct btrfs_fs_devices *fs_devices = NULL;
> + struct btrfs_device *device = NULL;
> int error = 0;
>
> if (!options)
> @@ -916,11 +916,13 @@ static int btrfs_parse_early_options(const char
> *options, fmode_t flags,
> error = -ENOMEM;
> goto out;
> }
> - error = btrfs_scan_one_device(device_name,
> - flags, holder, &fs_devices);
> + device = btrfs_scan_one_device(device_name,
> + flags, holder);
> kfree(device_name);
> - if (error)
> + if (IS_ERR(device)) {
> + error = PTR_ERR(device);
> goto out;
> + }
> }
> }
>
> @@ -1516,6 +1518,7 @@ static struct dentry *btrfs_mount_root(struct
> file_system_type *fs_type,
> {
> struct block_device *bdev = NULL;
> struct super_block *s;
> + struct btrfs_device *device = NULL;
> struct btrfs_fs_devices *fs_devices = NULL;
> struct btrfs_fs_info *fs_info = NULL;
> struct security_mnt_opts new_sec_opts;
> @@ -1537,9 +1540,13 @@ static struct dentry *btrfs_mount_root(struct
> file_system_type *fs_type,
> return ERR_PTR(error);
> }
>
> - error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
> - if (error)
> + device = btrfs_scan_one_device(device_name, mode, fs_type);
> + if (IS_ERR(device)) {
> + error = PTR_ERR(device);
> goto error_sec_opts;
> + }
> +
> + fs_devices = device->fs_devices;
>
> /*
> * Setup a dummy root and fs_info for test/set super. This is because
> @@ -2220,7 +2227,7 @@ static long btrfs_control_ioctl(struct file *file,
> unsigned int cmd,
> unsigned long arg)
> {
> struct btrfs_ioctl_vol_args *vol;
> - struct btrfs_fs_devices *fs_devices;
> + struct btrfs_device *device = NULL;
> int ret = -ENOTTY;
>
> if (!capable(CAP_SYS_ADMIN))
> @@ -2232,15 +2239,19 @@ static long btrfs_control_ioctl(struct file *file,
> unsigned int cmd,
>
> switch (cmd) {
> case BTRFS_IOC_SCAN_DEV:
> - ret = btrfs_scan_one_device(vol->name, FMODE_READ,
> - &btrfs_root_fs_type, &fs_devices);
> + device = btrfs_scan_one_device(vol->name, FMODE_READ,
> + &btrfs_root_fs_type);
> + ret = PTR_ERR_OR_ZERO(device);
> break;
> case BTRFS_IOC_DEVICES_READY:
> - ret = btrfs_scan_one_device(vol->name, FMODE_READ,
> - &btrfs_root_fs_type, &fs_devices);
> - if (ret)
> + device = btrfs_scan_one_device(vol->name, FMODE_READ,
> + &btrfs_root_fs_type);
> + if (IS_ERR(device)) {
> + ret = PTR_ERR(device);
> break;
> - ret = !(fs_devices->num_devices == fs_devices->total_devices);
> + }
> + ret = !(device->fs_devices->num_devices ==
> + device->fs_devices->total_devices);
> break;
> case BTRFS_IOC_GET_SUPPORTED_FEATURES:
> ret = btrfs_ioctl_get_supported_features((void __user*)arg);
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 52abada5c789..3bc479e8cc22 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -1212,14 +1212,13 @@ static int btrfs_read_disk_super(struct block_device
> *bdev, u64 bytenr,
> * and we are not allowed to call set_blocksize during the scan. The
> superblock
> * is read via pagecache
> */
> -int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
> - struct btrfs_fs_devices **fs_devices_ret)
> +struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
> + void *holder)
> {
> struct btrfs_super_block *disk_super;
> - struct btrfs_device *device;
> + struct btrfs_device *ret = NULL;
> struct block_device *bdev;
> struct page *page;
> - int ret = 0;
> u64 bytenr;
>
> /*
> @@ -1233,19 +1232,15 @@ int btrfs_scan_one_device(const char *path, fmode_t
> flags, void *holder,
>
> bdev = blkdev_get_by_path(path, flags, holder);
> if (IS_ERR(bdev))
> - return PTR_ERR(bdev);
> + return ERR_CAST(bdev);
>
> if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super)) {
> - ret = -EINVAL;
> + ret = ERR_PTR(-EINVAL);
> goto error_bdev_put;
> }
>
> mutex_lock(&uuid_mutex);
> - device = device_list_add(path, disk_super);
> - if (IS_ERR(device))
> - ret = PTR_ERR(device);
> - else
> - *fs_devices_ret = device->fs_devices;
> + ret = device_list_add(path, disk_super);
> mutex_unlock(&uuid_mutex);
>
> btrfs_release_disk_super(page);
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 9665b84b1026..06d8bb7dd557 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -403,8 +403,8 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info,
> struct bio *bio,
> int mirror_num, int async_submit);
> int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
> fmode_t flags, void *holder);
> -int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
> - struct btrfs_fs_devices **fs_devices_ret);
> +struct btrfs_device *btrfs_scan_one_device(const char *path,
> + fmode_t flags, void *holder);
> int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
> void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step);
> void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
>
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