Re: [RFC PATCH v1 6/6] exfat: take s_lock in read mode for iomap mapping paths

[Namjae Jeon]

> @@ -68,7 +68,7 @@ static int __exfat_iomap_begin(struct inode *inode, loff_t offset, loff_t length
>         num_clusters = exfat_bytes_to_cluster_round_up(sbi,
>                         offset + length) - exfat_bytes_to_cluster(sbi, offset);
>
> -       down_write(&sbi->s_lock);
> +       down_read(&sbi->s_lock);
If may_alloc is true, Should we use down_write() ?

>         iomap->bdev = inode->i_sb->s_bdev;
>         iomap->offset = offset;
>
> @@ -135,7 +135,7 @@ static int __exfat_iomap_begin(struct inode *inode, loff_t offset, loff_t length
>
>         iomap->flags |= IOMAP_F_MERGED;
>  out:
> -       up_write(&sbi->s_lock);
> +       up_read(&sbi->s_lock);
>         return err;
>  }