On 2021/03/23 2:39, Amir Goldstein wrote:
> 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.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/ext2/super.c | 5 +----
> fs/ext4/super.c | 5 +----
> fs/zonefs/super.c | 5 +----
> include/linux/statfs.h | 7 +++++++
> 4 files changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index 6c4753277916..0d679451657c 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;
> }
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index ad34a37278cd..3581c1cdc19e 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -6148,7 +6148,6 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
> struct ext4_sb_info *sbi = EXT4_SB(sb);
> struct ext4_super_block *es = sbi->s_es;
> ext4_fsblk_t overhead = 0, resv_blocks;
> - u64 fsid;
> s64 bfree;
> resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
>
> @@ -6169,9 +6168,7 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
> buf->f_files = le32_to_cpu(es->s_inodes_count);
> buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
> buf->f_namelen = EXT4_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);
>
> #ifdef CONFIG_QUOTA
> if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
> index 0fe76f376dee..e09810311162 100644
> --- a/fs/zonefs/super.c
> +++ b/fs/zonefs/super.c
> @@ -1104,7 +1104,6 @@ static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf)
> struct super_block *sb = dentry->d_sb;
> struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
> enum zonefs_ztype t;
> - u64 fsid;
>
> buf->f_type = ZONEFS_MAGIC;
> buf->f_bsize = sb->s_blocksize;
> @@ -1127,9 +1126,7 @@ static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf)
>
> spin_unlock(&sbi->s_lock);
>
> - fsid = le64_to_cpup((void *)sbi->s_uuid.b) ^
> - le64_to_cpup((void *)sbi->s_uuid.b + sizeof(u64));
> - buf->f_fsid = u64_to_fsid(fsid);
> + buf->f_fsid = uuid_to_fsid(sbi->s_uuid.b);
>
> return 0;
> }
> diff --git a/include/linux/statfs.h b/include/linux/statfs.h
> index 20f695b90aab..ed86ac090a1b 100644
> --- a/include/linux/statfs.h
> +++ b/include/linux/statfs.h
> @@ -50,4 +50,11 @@ static inline __kernel_fsid_t u64_to_fsid(u64 v)
> return (__kernel_fsid_t){.val = {(u32)v, (u32)(v>>32)}};
> }
>
> +/* Fold 16 bytes uuid to 64 bit fsid */
> +static inline __kernel_fsid_t uuid_to_fsid(__u8 *uuid)
> +{
> + return u64_to_fsid(le64_to_cpup((void *)uuid) ^
> + le64_to_cpup((void *)(uuid + sizeof(u64))));
> +}
> +
> #endif
>
For the zonefs bits, looks good to me.
Acked-by: Damien Le Moal <damien.lemoal@xxxxxxx>
--
Damien Le Moal
Western Digital Research
