[PATCH] erofs: derive fsid from on-disk UUID for .statfs() if possible

[Hongzhen Luo]

在 2024/4/9 17:36, Jingbo Xu 写道:
>
> On 4/9/24 4:11 PM, Hongzhen Luo wrote:
>> Use the superblock's UUID to generate the fsid when it's non-null.
>>
>> Signed-off-by: Hongzhen Luo <hongzhen at linux.alibaba.com>
>> ---
>>   fs/erofs/super.c | 12 +++++-------
>>   1 file changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
>> index c0eb139adb07..83bd8ee3b5ba 100644
>> --- a/fs/erofs/super.c
>> +++ b/fs/erofs/super.c
>> @@ -923,22 +923,20 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
>>   {
>>   	struct super_block *sb = dentry->d_sb;
>>   	struct erofs_sb_info *sbi = EROFS_SB(sb);
>> -	u64 id = 0;
>> -
>> -	if (!erofs_is_fscache_mode(sb))
>> -		id = huge_encode_dev(sb->s_bdev->bd_dev);
>>   
>>   	buf->f_type = sb->s_magic;
>>   	buf->f_bsize = sb->s_blocksize;
>>   	buf->f_blocks = sbi->total_blocks;
>>   	buf->f_bfree = buf->f_bavail = 0;
>> -
>>   	buf->f_files = ULLONG_MAX;
>>   	buf->f_ffree = ULLONG_MAX - sbi->inos;
>> -
>>   	buf->f_namelen = EROFS_NAME_LEN;
>>   
>> -	buf->f_fsid    = u64_to_fsid(id);
>> +	if (uuid_is_null(&sb->s_uuid))
>> +		buf->f_fsid = u64_to_fsid(erofs_is_fscache_mode(sb) ? 0 :
>> +				huge_encode_dev(sb->s_bdev->bd_dev));
>> +	else
>> +		buf->f_fsid = uuid_to_fsid((__u8 *)&sb->s_uuid);
> How about
>
> 	buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
>
> which looks cleaner.
>
> Otherwise LGTM.
>
> Reviewed-by: Jingbo Xu <jefflexu at linux.alibaba.com>
>
>
Thanks. I will send v2 later.

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Hongzhen