fs: introduce a wrapper uuid_to_fsid()
Some filesystem's use a digest of their uuid for f_fsid.
Create a simple wrapper for this open coded folding.
Filesystems that have a non null uuid but use the block device
number for f_fsid may also consider using this helper.
[JK: Added missing asm/byteorder.h include]
Link: https://lore.kernel.org/r/20210322173944.449469-2-amir73il@gmail.com
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 6c47532..0d67945 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1399,7 +1399,6 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
struct super_block *sb = dentry->d_sb;
struct ext2_sb_info *sbi = EXT2_SB(sb);
struct ext2_super_block *es = sbi->s_es;
- u64 fsid;
spin_lock(&sbi->s_lock);
@@ -1453,9 +1452,7 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
buf->f_ffree = ext2_count_free_inodes(sb);
es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
buf->f_namelen = EXT2_NAME_LEN;
- fsid = le64_to_cpup((void *)es->s_uuid) ^
- le64_to_cpup((void *)es->s_uuid + sizeof(u64));
- buf->f_fsid = u64_to_fsid(fsid);
+ buf->f_fsid = uuid_to_fsid(es->s_uuid);
spin_unlock(&sbi->s_lock);
return 0;
}
