Re: [PATCH] xfs: Don't flush inodes when project quota exceeded

[Jan Kara <jack@suse.cz>]

On Tue 13-11-12 01:36:13, Jan Kara wrote:
> When project quota gets exceeded xfs_iomap_write_delay() ends up flushing
> inodes because ENOSPC gets returned from xfs_bmapi_delay() instead of EDQUOT.
> This makes handling of writes over project quota rather slow as a simple test
> program shows:
> 	fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0644);
> 	for (i = 0; i < 50000; i++)
> 		pwrite(fd, buf, 4096, i*4096);
> 
> Writing 200 MB like this into a directory with 100 MB project quota takes
> around 6 minutes while it takes about 2 seconds with this patch applied. This
> actually happens in a real world load when nfs pushes data into a directory
> which is over project quota.
> 
> Fix the problem by replacing XFS_QMOPT_ENOSPC flag with XFS_QMOPT_EPDQUOT.
> That makes xfs_trans_reserve_quota_bydquots() return new error EPDQUOT when
> project quota is exceeded. xfs_bmapi_delay() then uses this flag so that
> xfs_iomap_write_delay() can distinguish real ENOSPC (requiring flushing)
> from exceeded project quota (not requiring flushing).
> 
> As a side effect this patch fixes inconsistency where e.g. xfs_create()
> returned EDQUOT even when project quota was exceeded.
  Ping? Any opinions?

								Honza
> 
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  fs/xfs/xfs_bmap.c        |    3 ++-
>  fs/xfs/xfs_iomap.c       |    8 ++++++--
>  fs/xfs/xfs_linux.h       |    1 +
>  fs/xfs/xfs_qm.c          |   13 +++++--------
>  fs/xfs/xfs_quota.h       |    2 +-
>  fs/xfs/xfs_trans_dquot.c |   18 +++++++++---------
>  6 files changed, 24 insertions(+), 21 deletions(-)
> 
> diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
> index 848ffa7..027398f 100644
> --- a/fs/xfs/xfs_bmap.c
> +++ b/fs/xfs/xfs_bmap.c
> @@ -4471,7 +4471,8 @@ xfs_bmapi_reserve_delalloc(
>  	 * allocated blocks already inside this loop.
>  	 */
>  	error = xfs_trans_reserve_quota_nblks(NULL, ip, (long)alen, 0,
> -			rt ? XFS_QMOPT_RES_RTBLKS : XFS_QMOPT_RES_REGBLKS);
> +			XFS_QMOPT_EPDQUOT |
> +			(rt ? XFS_QMOPT_RES_RTBLKS : XFS_QMOPT_RES_REGBLKS));
>  	if (error)
>  		return error;
>  
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 973dff6..86e8016 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -428,6 +428,7 @@ retry:
>  	case 0:
>  	case ENOSPC:
>  	case EDQUOT:
> +	case EPDQUOT:
>  		break;
>  	default:
>  		return XFS_ERROR(error);
> @@ -441,8 +442,11 @@ retry:
>  	 */
>  	if (nimaps == 0) {
>  		trace_xfs_delalloc_enospc(ip, offset, count);
> -		if (flushed)
> -			return XFS_ERROR(error ? error : ENOSPC);
> +		if (flushed) {
> +			if (error == 0 || error == EPDQUOT)
> +				error = ENOSPC;
> +			return XFS_ERROR(error);
> +		}
>  
>  		if (error == ENOSPC) {
>  			xfs_iunlock(ip, XFS_ILOCK_EXCL);
> diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
> index 828662f..31368df 100644
> --- a/fs/xfs/xfs_linux.h
> +++ b/fs/xfs/xfs_linux.h
> @@ -145,6 +145,7 @@
>  #define ENOATTR		ENODATA		/* Attribute not found */
>  #define EWRONGFS	EINVAL		/* Mount with wrong filesystem type */
>  #define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
> +#define EPDQUOT		EXFULL		/* Project quota exceeded */
>  
>  #define SYNCHRONIZE()	barrier()
>  #define __return_address __builtin_return_address(0)
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index 2e86fa0..99ace03 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -1790,7 +1790,7 @@ xfs_qm_vop_chown_reserve(
>  	uint		flags)
>  {
>  	xfs_mount_t	*mp = ip->i_mount;
> -	uint		delblks, blkflags, prjflags = 0;
> +	uint		delblks, blkflags;
>  	xfs_dquot_t	*unresudq, *unresgdq, *delblksudq, *delblksgdq;
>  	int		error;
>  
> @@ -1817,11 +1817,8 @@ xfs_qm_vop_chown_reserve(
>  		}
>  	}
>  	if (XFS_IS_OQUOTA_ON(ip->i_mount) && gdqp) {
> -		if (XFS_IS_PQUOTA_ON(ip->i_mount) &&
> -		     xfs_get_projid(ip) != be32_to_cpu(gdqp->q_core.d_id))
> -			prjflags = XFS_QMOPT_ENOSPC;
> -
> -		if (prjflags ||
> +		if ((XFS_IS_PQUOTA_ON(ip->i_mount) &&
> +		     xfs_get_projid(ip) != be32_to_cpu(gdqp->q_core.d_id)) ||
>  		    (XFS_IS_GQUOTA_ON(ip->i_mount) &&
>  		     ip->i_d.di_gid != be32_to_cpu(gdqp->q_core.d_id))) {
>  			delblksgdq = gdqp;
> @@ -1834,7 +1831,7 @@ xfs_qm_vop_chown_reserve(
>  
>  	if ((error = xfs_trans_reserve_quota_bydquots(tp, ip->i_mount,
>  				delblksudq, delblksgdq, ip->i_d.di_nblocks, 1,
> -				flags | blkflags | prjflags)))
> +				flags | blkflags)))
>  		return (error);
>  
>  	/*
> @@ -1851,7 +1848,7 @@ xfs_qm_vop_chown_reserve(
>  		ASSERT(unresudq || unresgdq);
>  		if ((error = xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount,
>  				delblksudq, delblksgdq, (xfs_qcnt_t)delblks, 0,
> -				flags | blkflags | prjflags)))
> +				flags | blkflags)))
>  			return (error);
>  		xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount,
>  				unresudq, unresgdq, -((xfs_qcnt_t)delblks), 0,
> diff --git a/fs/xfs/xfs_quota.h b/fs/xfs/xfs_quota.h
> index b50ec5b..264b455 100644
> --- a/fs/xfs/xfs_quota.h
> +++ b/fs/xfs/xfs_quota.h
> @@ -203,7 +203,7 @@ typedef struct xfs_qoff_logformat {
>  #define XFS_QMOPT_DOWARN        0x0000400 /* increase warning cnt if needed */
>  #define XFS_QMOPT_DQREPAIR	0x0001000 /* repair dquot if damaged */
>  #define XFS_QMOPT_GQUOTA	0x0002000 /* group dquot requested */
> -#define XFS_QMOPT_ENOSPC	0x0004000 /* enospc instead of edquot (prj) */
> +#define XFS_QMOPT_EPDQUOT	0x0004000 /* return EPDQUOT when project quota exceeded */
>  
>  /*
>   * flags to xfs_trans_mod_dquot to indicate which field needs to be
> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
> index 0c7fa54..27acce3 100644
> --- a/fs/xfs/xfs_trans_dquot.c
> +++ b/fs/xfs/xfs_trans_dquot.c
> @@ -728,8 +728,6 @@ xfs_trans_dqresv(
>  
>  error_return:
>  	xfs_dqunlock(dqp);
> -	if (flags & XFS_QMOPT_ENOSPC)
> -		return ENOSPC;
>  	return EDQUOT;
>  }
>  
> @@ -741,7 +739,6 @@ error_return:
>   * approach.
>   *
>   * flags = XFS_QMOPT_FORCE_RES evades limit enforcement. Used by chown.
> - *	   XFS_QMOPT_ENOSPC returns ENOSPC not EDQUOT.  Used by pquota.
>   *	   XFS_TRANS_DQ_RES_BLKS reserves regular disk blocks
>   *	   XFS_TRANS_DQ_RES_RTBLKS reserves realtime disk blocks
>   * dquots are unlocked on return, if they were not locked by caller.
> @@ -767,8 +764,7 @@ 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;
>  		resvd = 1;
> @@ -785,6 +781,12 @@ xfs_trans_reserve_quota_bydquots(
>  				xfs_trans_dqresv(tp, mp, udqp,
>  						 -nblks, -ninos, flags);
>  			}
> +			if (error == EDQUOT && XFS_IS_PQUOTA_ON(mp)) {
> +				if (flags & XFS_QMOPT_EPDQUOT)
> +					error = EPDQUOT;
> +				else
> +					error = ENOSPC;
> +			}
>  			return error;
>  		}
>  	}
> @@ -813,16 +815,14 @@ 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(ip->i_ino != mp->m_sb.sb_uquotino);
>  	ASSERT(ip->i_ino != mp->m_sb.sb_gquotino);
>  
>  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
> -	ASSERT((flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_ENOSPC)) ==
> +	ASSERT((flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_EPDQUOT)) ==
>  				XFS_TRANS_DQ_RES_RTBLKS ||
> -	       (flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_ENOSPC)) ==
> +	       (flags & ~(XFS_QMOPT_FORCE_RES | XFS_QMOPT_EPDQUOT)) ==
>  				XFS_TRANS_DQ_RES_BLKS);
>  
>  	/*
> -- 
> 1.7.1
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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