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

[Jan Kara <jack@suse.cz>]

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.

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

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