Re: [PATCH 5/5] hugetlbfs: fix confusing hugetlbfs stat

Mike Kravetz
2022-07-22T00:28:25Z

On 07/21/22 21:16, Miaohe Lin wrote:
> When size option is not specified, f_blocks, f_bavail and f_bfree will be
> set to -1 instead of 0. Likewise, when nr_inodes is not specified, f_files
> and f_ffree will be set to -1 too. Check max_hpages and max_inodes against
> -1 first to make sure 0 is reported for max/free/used when no limit is set
> as the comment states.

Just curious, where are you seeing values reported as -1? The check
for sbinfo->spool was supposed to handle these cases. Seems like it
should handle the max_hpages == -1 case. But, it doesn't look like it
considers the max_inodes == -1 case.

If I create/mount a hugetlb filesystem without specifying size or nr_inodes,
df seems to report zero instead of -1.

Just want to understand the reasoning behind the change.
--
Mike Kravetz

>
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> ---
> fs/hugetlbfs/inode.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 19fc62a9c2fe..44da9828e171 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -1083,16 +1083,20 @@ static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> /* If no limits set, just report 0 for max/free/used
> * blocks, like simple_statfs() */
> if (sbinfo->spool) {
> - long free_pages;
> -
> spin_lock_irq(&sbinfo->spool->lock);
> - buf->f_blocks = sbinfo->spool->max_hpages;
> - free_pages = sbinfo->spool->max_hpages
> - - sbinfo->spool->used_hpages;
> - buf->f_bavail = buf->f_bfree = free_pages;
> + if (sbinfo->spool->max_hpages != -1) {
> + long free_pages;
> +
> + buf->f_blocks = sbinfo->spool->max_hpages;
> + free_pages = sbinfo->spool->max_hpages
> + - sbinfo->spool->used_hpages;
> + buf->f_bavail = buf->f_bfree = free_pages;
> + }
> spin_unlock_irq(&sbinfo->spool->lock);
> - buf->f_files = sbinfo->max_inodes;
> - buf->f_ffree = sbinfo->free_inodes;
> + if (sbinfo->max_inodes != -1) {
> + buf->f_files = sbinfo->max_inodes;
> + buf->f_ffree = sbinfo->free_inodes;
> + }
> }
> spin_unlock(&sbinfo->stat_lock);
> }
> --
> 2.23.0
>