Re: [PATCH] btrfs-progs: mkfs: use path_canonicalize for input device

[Qu Wenruo <wqu@suse.com>]

在 2025/5/15 23:46, Anand Jain 写道:
> Canonicalize the input device's path before using it.
> So that we show the device path that matches with the /proc/fs/
> 
> Before:
>    $ mkfs.btrfs -fq /dev/vg_fstests/lv1 /dev/sdb > /dev/null
> 
>    $ blkid --uuid c3bf2107-292d-4c7f-a288-0fa922ebd71a
>    /dev/mapper/vg_fstests-lv1
> 
>    $ mount --verbose /dev/vg_fstests/lv1 /mnt/scratch
>    mount: /dev/mapper/vg_fstests-lv1 mounted on /mnt/scratch.
> 
>    $ cat /proc/self/mounts | grep scratch
>    /dev/vg_fstests/lv1 /mnt/scratch btrfs rw,relatime,space_cache=v2,subvolid=5,subvol=/ 0 0
> 
> After:
>    $ mkfs.btrfs -fq /dev/vg_fstests/lv1 /dev/sdb > /dev/null
> 
>    $ blkid --uuid c774b4a6-3ad2-4b15-834a-894dfc898aa9
>    /dev/mapper/vg_fstests-lv1
> 
>    $ mount --verbose /dev/vg_fstests/lv1 /mnt/scratch
>    mount: /dev/mapper/vg_fstests-lv1 mounted on /mnt/scratch.
> 
>    $ cat /proc/self/mounts | grep scratch
>    /dev/mapper/vg_fstests-lv1 /mnt/scratch btrfs rw,relatime,space_cache=v2,subvolid=5,subvol=/ 0 0

I do not think this is the correct way to go.

It looks more like a bug in libblkid.

Please explain why the problem happens, not workaround it without any 
reasons.

Thanks,
Qu

> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> Link: https://lore.kernel.org/linux-btrfs/5f401c48-29f5-403e-8c39-50188028ad00@oracle.com/
> ---
>   mkfs/main.c | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/mkfs/main.c b/mkfs/main.c
> index 4c2ce98c784c..e6466d88313a 100644
> --- a/mkfs/main.c
> +++ b/mkfs/main.c
> @@ -1537,7 +1537,7 @@ int BOX_MAIN(mkfs)(int argc, char **argv)
>   	}
>   
>   	for (i = 0; i < device_count; i++) {
> -		file = argv[optind++];
> +		file = path_canonicalize(argv[optind++]);
>   
>   		if (source_dir && path_exists(file) == 0)
>   			ret = 0;
> @@ -1553,7 +1553,7 @@ int BOX_MAIN(mkfs)(int argc, char **argv)
>   	optind = saved_optind;
>   	device_count = argc - optind;
>   
> -	file = argv[optind++];
> +	file = path_canonicalize(argv[optind++]);
>   	ssd = device_get_rotational(file);
>   	if (opt_zoned) {
>   		if (!zone_size(file)) {
> @@ -1752,7 +1752,7 @@ int BOX_MAIN(mkfs)(int argc, char **argv)
>   	for (i = saved_optind; i < saved_optind + device_count; i++) {
>   		char *path;
>   
> -		path = argv[i];
> +		path = path_canonicalize(argv[i]);
>   		ret = test_minimum_size(path, min_dev_size);
>   		if (ret < 0) {
>   			error("failed to check size for %s: %m", path);
> @@ -1816,7 +1816,8 @@ int BOX_MAIN(mkfs)(int argc, char **argv)
>   	opt_oflags = O_RDWR;
>   	for (i = 0; i < device_count; i++) {
>   		if (opt_zoned &&
> -		    zoned_model(argv[optind + i - 1]) == ZONED_HOST_MANAGED) {
> +		    zoned_model(path_canonicalize(argv[optind + i - 1])) ==
> +							ZONED_HOST_MANAGED) {
>   			opt_oflags |= O_DIRECT;
>   			break;
>   		}
> @@ -1824,7 +1825,7 @@ int BOX_MAIN(mkfs)(int argc, char **argv)
>   
>   	/* Start threads */
>   	for (i = 0; i < device_count; i++) {
> -		prepare_ctx[i].file = argv[optind + i - 1];
> +		prepare_ctx[i].file = path_canonicalize(argv[optind + i - 1]);
>   		prepare_ctx[i].byte_count = byte_count;
>   		prepare_ctx[i].dev_byte_count = byte_count;
>   		ret = pthread_create(&t_prepare[i], NULL, prepare_one_device,
> @@ -2198,7 +2199,7 @@ out:
>   		optind = saved_optind;
>   		device_count = argc - optind;
>   		while (device_count-- > 0) {
> -			file = argv[optind++];
> +			file = path_canonicalize(argv[optind++]);
>   			if (path_is_block_device(file) == 1)
>   				btrfs_register_one_device(file);
>   		}