Re: [PATCH] btrfs: free unlinked replace target on initialization failure

[Qu Wenruo <wqu@suse.com>]

在 2026/8/8 14:12, Guanghui Yang 写道:
> btrfs_init_dev_replace_tgtdev() allocates the replacement target before
> looking up its dev_t and initializing its zoned device information. If
> either lookup_bdev() or btrfs_get_dev_zone_info() fails, the device has
> not been linked into fs_devices->devices yet, but the error path only
> drops the block device file reference.
> 
> Free the allocated device on this error path to release its name,
> allocation state, zone info, and the device itself.
> 
> Signed-off-by: Guanghui Yang <3497809730@qq.com>

I have a very strong feeling that you're using LLM hunting down bugs.

In that case, be responsible and disclose the usage of LLM.

> ---
>   fs/btrfs/dev-replace.c | 4 ++++
>   fs/btrfs/volumes.c     | 2 +-
>   fs/btrfs/volumes.h     | 1 +
>   3 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 318ddb790..3c17481c9 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -240,6 +240,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>   	struct block_device *bdev;
>   	u64 devid = BTRFS_DEV_REPLACE_DEVID;
>   	int ret = 0;
> +	bool device_allocated = false;

You can just initialize @device to NULL, and use that pointer to 
determine if the device is properly allocated.
>   
>   	*device_out = NULL;
>   	if (srcdev->fs_devices->seeding) {
> @@ -287,6 +288,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>   		ret = PTR_ERR(device);
>   		goto error;
>   	}
> +	device_allocated = true;
>   
>   	ret = lookup_bdev(device_path, &device->devt);
>   	if (ret)
> @@ -327,6 +329,8 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>   	return 0;
>   
>   error:
> +	if (device_allocated)
> +		btrfs_free_device(device);
>   	bdev_fput(bdev_file);
>   	return ret;
>   }
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index a8e27db8e..c479f268a 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -402,7 +402,7 @@ static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
>   	return fs_devs;
>   }
>   
> -static void btrfs_free_device(struct btrfs_device *device)
> +void btrfs_free_device(struct btrfs_device *device)
>   {
>   	WARN_ON(!list_empty(&device->post_commit_list));
>   	/*
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index eaf23c0dc..ecab3ce3c 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -795,6 +795,7 @@ int btrfs_run_dev_stats(struct btrfs_trans_handle *trans);
>   void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_device *srcdev);
>   void btrfs_rm_dev_replace_free_srcdev(struct btrfs_device *srcdev);
>   void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev);
> +void btrfs_free_device(struct btrfs_device *device);
>   unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
>   				    u64 logical);
>   u64 btrfs_calc_stripe_length(const struct btrfs_chunk_map *map);