Re: [PATCH 01/17] xfs: make qi_dquots a 64-bit value

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Oct 13, 2025 at 11:48:02AM +0900, Christoph Hellwig wrote:
> qi_dquots counts all quotas in the file system, which can be up to
> 3 * UINT_MAX and overflow a 32-bit counter, but can't be negative.
> Make qi_dquots a uint64_t, and saturate the value to UINT_MAX for
> userspace reporting.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_qm.h       | 2 +-
>  fs/xfs/xfs_quotaops.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_qm.h b/fs/xfs/xfs_qm.h
> index 35b64bc3a7a8..e88ed6ad0e65 100644
> --- a/fs/xfs/xfs_qm.h
> +++ b/fs/xfs/xfs_qm.h
> @@ -57,7 +57,7 @@ struct xfs_quotainfo {
>  	struct xfs_inode	*qi_pquotaip;	/* project quota inode */
>  	struct xfs_inode	*qi_dirip;	/* quota metadir */
>  	struct list_lru		qi_lru;
> -	int			qi_dquots;
> +	uint64_t		qi_dquots;
>  	struct mutex		qi_quotaofflock;/* to serialize quotaoff */
>  	xfs_filblks_t		qi_dqchunklen;	/* # BBs in a chunk of dqs */
>  	uint			qi_dqperchunk;	/* # ondisk dq in above chunk */
> diff --git a/fs/xfs/xfs_quotaops.c b/fs/xfs/xfs_quotaops.c
> index 4c7f7ce4fd2f..1045c4c262ad 100644
> --- a/fs/xfs/xfs_quotaops.c
> +++ b/fs/xfs/xfs_quotaops.c
> @@ -65,7 +65,7 @@ xfs_fs_get_quota_state(
>  	memset(state, 0, sizeof(*state));
>  	if (!XFS_IS_QUOTA_ON(mp))
>  		return 0;
> -	state->s_incoredqs = q->qi_dquots;
> +	state->s_incoredqs = max_t(uint64_t, q->qi_dquots, UINT_MAX);

Isn't this min_t?  Surely we don't want to return 0xFFFFFFFF when
there's only 3 dquots loaded in the system?

--D

>  	if (XFS_IS_UQUOTA_ON(mp))
>  		state->s_state[USRQUOTA].flags |= QCI_ACCT_ENABLED;
>  	if (XFS_IS_UQUOTA_ENFORCED(mp))
> -- 
> 2.47.3
> 
>