Re: [PATCH 2/2] xfs: remove XFS_QMOPT_ENOSPC flag

[Brian Foster <bfoster@redhat.com>]

On Thu, May 07, 2020 at 11:00:34PM -0500, Eric Sandeen wrote:
> The only place we return -EDQUOT, and therefore need to make a decision
> about returning -ENOSPC for project quota instead, is in xfs_trans_dqresv().
> 
> So there's no reason to be setting and clearing XFS_QMOPT_ENOSPC at higher
> levels; if xfs_trans_dqresv has failed, test if the dqp we were were handed
> is a project quota and if so, return -ENOSPC instead of EDQUOT.  The
> complexity is just a leftover from when project & group quota were mutually
> exclusive and shared some codepaths.
> 
> The prior patch was the trivial bugfix, this is the slightly more involved
> cleanup.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---

Hmm so what about callers that don't pass QMOPT_ENOSPC? For example, it
looks like various xfs_trans_reserve_quota() calls pass a pdqp but don't
set the flag. Is the intent to change behavior such that -ENOSPC is
unconditional for project quota reservation failures?

Brian

> 
> Patch 1 was the trivial bugfix, this is the slightly more involved cleanup.
> 
> diff --git a/fs/xfs/libxfs/xfs_quota_defs.h b/fs/xfs/libxfs/xfs_quota_defs.h
> index b2113b17e53c..56d9dd787e7b 100644
> --- a/fs/xfs/libxfs/xfs_quota_defs.h
> +++ b/fs/xfs/libxfs/xfs_quota_defs.h
> @@ -100,7 +100,6 @@ typedef uint16_t	xfs_qwarncnt_t;
>  #define XFS_QMOPT_FORCE_RES	0x0000010 /* ignore quota limits */
>  #define XFS_QMOPT_SBVERSION	0x0000040 /* change superblock version num */
>  #define XFS_QMOPT_GQUOTA	0x0002000 /* group dquot requested */
> -#define XFS_QMOPT_ENOSPC	0x0004000 /* enospc instead of edquot (prj) */
>  
>  /*
>   * flags to xfs_trans_mod_dquot to indicate which field needs to be
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index c225691fad15..591779aa2fd0 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -1808,7 +1808,7 @@ xfs_qm_vop_chown_reserve(
>  {
>  	struct xfs_mount	*mp = ip->i_mount;
>  	uint64_t		delblks;
> -	unsigned int		blkflags, prjflags = 0;
> +	unsigned int		blkflags;
>  	struct xfs_dquot	*udq_unres = NULL;
>  	struct xfs_dquot	*gdq_unres = NULL;
>  	struct xfs_dquot	*pdq_unres = NULL;
> @@ -1849,7 +1849,6 @@ xfs_qm_vop_chown_reserve(
>  
>  	if (XFS_IS_PQUOTA_ON(ip->i_mount) && pdqp &&
>  	    ip->i_d.di_projid != be32_to_cpu(pdqp->q_core.d_id)) {
> -		prjflags = XFS_QMOPT_ENOSPC;
>  		pdq_delblks = pdqp;
>  		if (delblks) {
>  			ASSERT(ip->i_pdquot);
> @@ -1859,8 +1858,7 @@ xfs_qm_vop_chown_reserve(
>  
>  	error = xfs_trans_reserve_quota_bydquots(tp, ip->i_mount,
>  				udq_delblks, gdq_delblks, pdq_delblks,
> -				ip->i_d.di_nblocks, 1,
> -				flags | blkflags | prjflags);
> +				ip->i_d.di_nblocks, 1, flags | blkflags);
>  	if (error)
>  		return error;
>  
> @@ -1878,8 +1876,7 @@ xfs_qm_vop_chown_reserve(
>  		ASSERT(udq_unres || gdq_unres || pdq_unres);
>  		error = xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount,
>  			    udq_delblks, gdq_delblks, pdq_delblks,
> -			    (xfs_qcnt_t)delblks, 0,
> -			    flags | blkflags | prjflags);
> +			    (xfs_qcnt_t)delblks, 0, flags | blkflags);
>  		if (error)
>  			return error;
>  		xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount,
> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
> index 2c3557a80e69..2c07897a3c37 100644
> --- a/fs/xfs/xfs_trans_dquot.c
> +++ b/fs/xfs/xfs_trans_dquot.c
> @@ -711,7 +711,7 @@ xfs_trans_dqresv(
>  
>  error_return:
>  	xfs_dqunlock(dqp);
> -	if (flags & XFS_QMOPT_ENOSPC)
> +	if (XFS_QM_ISPDQ(dqp))
>  		return -ENOSPC;
>  	return -EDQUOT;
>  }
> @@ -751,15 +751,13 @@ xfs_trans_reserve_quota_bydquots(
>  	ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
>  
>  	if (udqp) {
> -		error = xfs_trans_dqresv(tp, mp, udqp, nblks, ninos,
> -					(flags & ~XFS_QMOPT_ENOSPC));
> +		error = xfs_trans_dqresv(tp, mp, udqp, nblks, ninos, flags);
>  		if (error)
>  			return error;
>  	}
>  
>  	if (gdqp) {
> -		error = xfs_trans_dqresv(tp, mp, gdqp, nblks, ninos,
> -					(flags & ~XFS_QMOPT_ENOSPC));
> +		error = xfs_trans_dqresv(tp, mp, gdqp, nblks, ninos, flags);
>  		if (error)
>  			goto unwind_usr;
>  	}
> @@ -804,16 +802,12 @@ xfs_trans_reserve_quota_nblks(
>  
>  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
>  		return 0;
> -	if (XFS_IS_PQUOTA_ON(mp))
> -		flags |= XFS_QMOPT_ENOSPC;
>  
>  	ASSERT(!xfs_is_quota_inode(&mp->m_sb, ip->i_ino));
>  
>  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
> -	ASSERT((flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_ENOSPC)) ==
> -				XFS_TRANS_DQ_RES_RTBLKS ||
> -	       (flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_ENOSPC)) ==
> -				XFS_TRANS_DQ_RES_BLKS);
> +	ASSERT((flags & ~(XFS_QMOPT_FORCE_RES)) == XFS_TRANS_DQ_RES_RTBLKS ||
> +	       (flags & ~(XFS_QMOPT_FORCE_RES)) == XFS_TRANS_DQ_RES_BLKS);
>  
>  	/*
>  	 * Reserve nblks against these dquots, with trans as the mediator.
> 
>