[PATCH v3 0/5] xfs: random fixes for disk quota

[PATCH v3 0/5] xfs: random fixes for disk quota

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@tencent.com>

Hi all,

This patchset include random fixes and code cleanups for disk quota.
In order to make it easier to track, I bundle them up and put all
the scattered patches into a single patchset.

Changes for v3:
 -add a separate patch to delete duplicated tp->t_dqinfo null check
  and allocation.

Changes for v2: 
 -add the ASSERT for the arguments O_{u,g,p}dqpp.
 -fix the strange indent.
 -remove the XFS_TRANS_DQ_DIRTY flag.
 -add more commit log description for delta judgement.

Kaixu Xia (5):
  xfs: do the ASSERT for the arguments O_{u,g,p}dqpp
  xfs: fix the indent in xfs_trans_mod_dquot
  xfs: delete duplicated tp->t_dqinfo null check and allocation
  xfs: check tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag
  xfs: directly return if the delta equal to zero

 fs/xfs/libxfs/xfs_shared.h |  1 -
 fs/xfs/xfs_inode.c         |  8 +---
 fs/xfs/xfs_qm.c            |  3 ++
 fs/xfs/xfs_trans_dquot.c   | 75 ++++++++++++--------------------------
 4 files changed, 27 insertions(+), 60 deletions(-)

-- 
2.20.0

[PATCH v3 1/5] xfs: do the ASSERT for the arguments O_{u,g,p}dqpp

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@tencent.com>

If we pass in XFS_QMOPT_{U,G,P}QUOTA flags and different uid/gid/prid
than them currently associated with the inode, the arguments
O_{u,g,p}dqpp shouldn't be NULL, so add the ASSERT for them.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_qm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 44509decb4cd..b2a9abee8b2b 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1662,6 +1662,7 @@ xfs_qm_vop_dqalloc(
 	}
 
 	if ((flags & XFS_QMOPT_UQUOTA) && XFS_IS_UQUOTA_ON(mp)) {
+		ASSERT(O_udqpp);
 		if (!uid_eq(inode->i_uid, uid)) {
 			/*
 			 * What we need is the dquot that has this uid, and
@@ -1695,6 +1696,7 @@ xfs_qm_vop_dqalloc(
 		}
 	}
 	if ((flags & XFS_QMOPT_GQUOTA) && XFS_IS_GQUOTA_ON(mp)) {
+		ASSERT(O_gdqpp);
 		if (!gid_eq(inode->i_gid, gid)) {
 			xfs_iunlock(ip, lockflags);
 			error = xfs_qm_dqget(mp, from_kgid(user_ns, gid),
@@ -1712,6 +1714,7 @@ xfs_qm_vop_dqalloc(
 		}
 	}
 	if ((flags & XFS_QMOPT_PQUOTA) && XFS_IS_PQUOTA_ON(mp)) {
+		ASSERT(O_pdqpp);
 		if (ip->i_d.di_projid != prid) {
 			xfs_iunlock(ip, lockflags);
 			error = xfs_qm_dqget(mp, prid,
-- 
2.20.0

[PATCH v3 2/5] xfs: fix the indent in xfs_trans_mod_dquot

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@tencent.com>

The formatting is strange in xfs_trans_mod_dquot, so do a reindent.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_trans_dquot.c | 43 ++++++++++++++--------------------------
 1 file changed, 15 insertions(+), 28 deletions(-)

diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
index 133fc6fc3edd..fe45b0c3970c 100644
--- a/fs/xfs/xfs_trans_dquot.c
+++ b/fs/xfs/xfs_trans_dquot.c
@@ -221,36 +221,27 @@ xfs_trans_mod_dquot(
 	}
 
 	switch (field) {
-
-		/*
-		 * regular disk blk reservation
-		 */
-	      case XFS_TRANS_DQ_RES_BLKS:
+	/* regular disk blk reservation */
+	case XFS_TRANS_DQ_RES_BLKS:
 		qtrx->qt_blk_res += delta;
 		break;
 
-		/*
-		 * inode reservation
-		 */
-	      case XFS_TRANS_DQ_RES_INOS:
+	/* inode reservation */
+	case XFS_TRANS_DQ_RES_INOS:
 		qtrx->qt_ino_res += delta;
 		break;
 
-		/*
-		 * disk blocks used.
-		 */
-	      case XFS_TRANS_DQ_BCOUNT:
+	/* disk blocks used. */
+	case XFS_TRANS_DQ_BCOUNT:
 		qtrx->qt_bcount_delta += delta;
 		break;
 
-	      case XFS_TRANS_DQ_DELBCOUNT:
+	case XFS_TRANS_DQ_DELBCOUNT:
 		qtrx->qt_delbcnt_delta += delta;
 		break;
 
-		/*
-		 * Inode Count
-		 */
-	      case XFS_TRANS_DQ_ICOUNT:
+	/* Inode Count */
+	case XFS_TRANS_DQ_ICOUNT:
 		if (qtrx->qt_ino_res && delta > 0) {
 			qtrx->qt_ino_res_used += delta;
 			ASSERT(qtrx->qt_ino_res >= qtrx->qt_ino_res_used);
@@ -258,17 +249,13 @@ xfs_trans_mod_dquot(
 		qtrx->qt_icount_delta += delta;
 		break;
 
-		/*
-		 * rtblk reservation
-		 */
-	      case XFS_TRANS_DQ_RES_RTBLKS:
+	/* rtblk reservation */
+	case XFS_TRANS_DQ_RES_RTBLKS:
 		qtrx->qt_rtblk_res += delta;
 		break;
 
-		/*
-		 * rtblk count
-		 */
-	      case XFS_TRANS_DQ_RTBCOUNT:
+	/* rtblk count */
+	case XFS_TRANS_DQ_RTBCOUNT:
 		if (qtrx->qt_rtblk_res && delta > 0) {
 			qtrx->qt_rtblk_res_used += delta;
 			ASSERT(qtrx->qt_rtblk_res >= qtrx->qt_rtblk_res_used);
@@ -276,11 +263,11 @@ xfs_trans_mod_dquot(
 		qtrx->qt_rtbcount_delta += delta;
 		break;
 
-	      case XFS_TRANS_DQ_DELRTBCOUNT:
+	case XFS_TRANS_DQ_DELRTBCOUNT:
 		qtrx->qt_delrtb_delta += delta;
 		break;
 
-	      default:
+	default:
 		ASSERT(0);
 	}
 
-- 
2.20.0

[PATCH v3 3/5] xfs: delete duplicated tp->t_dqinfo null check and allocation

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@tencent.com>

The function xfs_trans_mod_dquot_byino() wrap around xfs_trans_mod_dquot()
to account for quotas, both of them do the null check and allocation. Thus
we can delete the duplicated operation in xfs_trans_mod_dquot_byino().

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
---
 fs/xfs/xfs_trans_dquot.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
index fe45b0c3970c..1b56065c9ff1 100644
--- a/fs/xfs/xfs_trans_dquot.c
+++ b/fs/xfs/xfs_trans_dquot.c
@@ -143,9 +143,6 @@ xfs_trans_mod_dquot_byino(
 	    xfs_is_quota_inode(&mp->m_sb, ip->i_ino))
 		return;
 
-	if (tp->t_dqinfo == NULL)
-		xfs_trans_alloc_dqinfo(tp);
-
 	if (XFS_IS_UQUOTA_ON(mp) && ip->i_udquot)
 		(void) xfs_trans_mod_dquot(tp, ip->i_udquot, field, delta);
 	if (XFS_IS_GQUOTA_ON(mp) && ip->i_gdquot)
-- 
2.20.0

Re: [PATCH v3 3/5] xfs: delete duplicated tp->t_dqinfo null check and allocation

[Darrick J. Wong]

On Wed, Oct 07, 2020 at 10:51:10PM +0800, xiakaixu1987@gmail.com wrote:
> From: Kaixu Xia <kaixuxia@tencent.com>
> 
> The function xfs_trans_mod_dquot_byino() wrap around xfs_trans_mod_dquot()
> to account for quotas, both of them do the null check and allocation. Thus
> we can delete the duplicated operation in xfs_trans_mod_dquot_byino().
> 
> Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>

Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_trans_dquot.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
> index fe45b0c3970c..1b56065c9ff1 100644
> --- a/fs/xfs/xfs_trans_dquot.c
> +++ b/fs/xfs/xfs_trans_dquot.c
> @@ -143,9 +143,6 @@ xfs_trans_mod_dquot_byino(
>  	    xfs_is_quota_inode(&mp->m_sb, ip->i_ino))
>  		return;
>  
> -	if (tp->t_dqinfo == NULL)
> -		xfs_trans_alloc_dqinfo(tp);
> -
>  	if (XFS_IS_UQUOTA_ON(mp) && ip->i_udquot)
>  		(void) xfs_trans_mod_dquot(tp, ip->i_udquot, field, delta);
>  	if (XFS_IS_GQUOTA_ON(mp) && ip->i_gdquot)
> -- 
> 2.20.0
> 

[PATCH v3 4/5] xfs: check tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@tencent.com>

Nowadays the only things that the XFS_TRANS_DQ_DIRTY flag seems to do
are indicates the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}] values
changed and check in xfs_trans_apply_dquot_deltas() and the unreserve
variant xfs_trans_unreserve_and_mod_dquots(). Actually, we also can
use the tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag, that
is to say, we allocate the new tp->t_dqinfo only when the qtrx values
changed, so the tp->t_dqinfo value isn't NULL equals the XFS_TRANS_DQ_DIRTY
flag is set, we only need to check if tp->t_dqinfo == NULL in
xfs_trans_apply_dquot_deltas() and its unreserve variant to determine
whether lock all of the dquots and join them to the transaction.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
---
 fs/xfs/libxfs/xfs_shared.h |  1 -
 fs/xfs/xfs_inode.c         |  8 +-------
 fs/xfs/xfs_trans_dquot.c   | 17 ++---------------
 3 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index c795ae47b3c9..8c61a461bf7b 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -62,7 +62,6 @@ void	xfs_log_get_max_trans_res(struct xfs_mount *mp,
 #define	XFS_TRANS_SB_DIRTY	0x02	/* superblock is modified */
 #define	XFS_TRANS_PERM_LOG_RES	0x04	/* xact took a permanent log res */
 #define	XFS_TRANS_SYNC		0x08	/* make commit synchronous */
-#define XFS_TRANS_DQ_DIRTY	0x10	/* at least one dquot in trx dirty */
 #define XFS_TRANS_RESERVE	0x20    /* OK to use reserved data blocks */
 #define XFS_TRANS_NO_WRITECOUNT 0x40	/* do not elevate SB writecount */
 #define XFS_TRANS_RES_FDBLKS	0x80	/* reserve newly freed blocks */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 49624973eecc..9108eed0ea45 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -941,7 +941,6 @@ xfs_dir_ialloc(
 	xfs_buf_t	*ialloc_context = NULL;
 	int		code;
 	void		*dqinfo;
-	uint		tflags;
 
 	tp = *tpp;
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
@@ -1000,12 +999,9 @@ xfs_dir_ialloc(
 		 * and attach it to the next transaction.
 		 */
 		dqinfo = NULL;
-		tflags = 0;
 		if (tp->t_dqinfo) {
 			dqinfo = (void *)tp->t_dqinfo;
 			tp->t_dqinfo = NULL;
-			tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
-			tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
 		}
 
 		code = xfs_trans_roll(&tp);
@@ -1013,10 +1009,8 @@ xfs_dir_ialloc(
 		/*
 		 * Re-attach the quota info that we detached from prev trx.
 		 */
-		if (dqinfo) {
+		if (dqinfo)
 			tp->t_dqinfo = dqinfo;
-			tp->t_flags |= tflags;
-		}
 
 		if (code) {
 			xfs_buf_relse(ialloc_context);
diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
index 1b56065c9ff1..0ebfd7930382 100644
--- a/fs/xfs/xfs_trans_dquot.c
+++ b/fs/xfs/xfs_trans_dquot.c
@@ -84,13 +84,6 @@ xfs_trans_dup_dqinfo(
 
 	xfs_trans_alloc_dqinfo(ntp);
 
-	/*
-	 * Because the quota blk reservation is carried forward,
-	 * it is also necessary to carry forward the DQ_DIRTY flag.
-	 */
-	if (otp->t_flags & XFS_TRANS_DQ_DIRTY)
-		ntp->t_flags |= XFS_TRANS_DQ_DIRTY;
-
 	for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
 		oqa = otp->t_dqinfo->dqs[j];
 		nqa = ntp->t_dqinfo->dqs[j];
@@ -270,8 +263,6 @@ xfs_trans_mod_dquot(
 
 	if (delta)
 		trace_xfs_trans_mod_dquot_after(qtrx);
-
-	tp->t_flags |= XFS_TRANS_DQ_DIRTY;
 }
 
 
@@ -348,7 +339,7 @@ xfs_trans_apply_dquot_deltas(
 	int64_t			totalbdelta;
 	int64_t			totalrtbdelta;
 
-	if (!(tp->t_flags & XFS_TRANS_DQ_DIRTY))
+	if (!tp->t_dqinfo)
 		return;
 
 	ASSERT(tp->t_dqinfo);
@@ -490,7 +481,7 @@ xfs_trans_unreserve_and_mod_dquots(
 	struct xfs_dqtrx	*qtrx, *qa;
 	bool			locked;
 
-	if (!tp->t_dqinfo || !(tp->t_flags & XFS_TRANS_DQ_DIRTY))
+	if (!tp->t_dqinfo)
 		return;
 
 	for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
@@ -695,7 +686,6 @@ xfs_trans_dqresv(
 	 * because we don't have the luxury of a transaction envelope then.
 	 */
 	if (tp) {
-		ASSERT(tp->t_dqinfo);
 		ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
 		if (nblks != 0)
 			xfs_trans_mod_dquot(tp, dqp,
@@ -749,9 +739,6 @@ xfs_trans_reserve_quota_bydquots(
 	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
 		return 0;
 
-	if (tp && tp->t_dqinfo == NULL)
-		xfs_trans_alloc_dqinfo(tp);
-
 	ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
 
 	if (udqp) {
-- 
2.20.0

Re: [PATCH v3 4/5] xfs: check tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag

[Darrick J. Wong]

On Wed, Oct 07, 2020 at 10:51:11PM +0800, xiakaixu1987@gmail.com wrote:
> From: Kaixu Xia <kaixuxia@tencent.com>
> 
> Nowadays the only things that the XFS_TRANS_DQ_DIRTY flag seems to do
> are indicates the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}] values
> changed and check in xfs_trans_apply_dquot_deltas() and the unreserve
> variant xfs_trans_unreserve_and_mod_dquots(). Actually, we also can
> use the tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag, that
> is to say, we allocate the new tp->t_dqinfo only when the qtrx values
> changed, so the tp->t_dqinfo value isn't NULL equals the XFS_TRANS_DQ_DIRTY
> flag is set, we only need to check if tp->t_dqinfo == NULL in
> xfs_trans_apply_dquot_deltas() and its unreserve variant to determine
> whether lock all of the dquots and join them to the transaction.
> 
> Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
> ---
>  fs/xfs/libxfs/xfs_shared.h |  1 -
>  fs/xfs/xfs_inode.c         |  8 +-------
>  fs/xfs/xfs_trans_dquot.c   | 17 ++---------------
>  3 files changed, 3 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
> index c795ae47b3c9..8c61a461bf7b 100644
> --- a/fs/xfs/libxfs/xfs_shared.h
> +++ b/fs/xfs/libxfs/xfs_shared.h
> @@ -62,7 +62,6 @@ void	xfs_log_get_max_trans_res(struct xfs_mount *mp,
>  #define	XFS_TRANS_SB_DIRTY	0x02	/* superblock is modified */
>  #define	XFS_TRANS_PERM_LOG_RES	0x04	/* xact took a permanent log res */
>  #define	XFS_TRANS_SYNC		0x08	/* make commit synchronous */
> -#define XFS_TRANS_DQ_DIRTY	0x10	/* at least one dquot in trx dirty */
>  #define XFS_TRANS_RESERVE	0x20    /* OK to use reserved data blocks */
>  #define XFS_TRANS_NO_WRITECOUNT 0x40	/* do not elevate SB writecount */
>  #define XFS_TRANS_RES_FDBLKS	0x80	/* reserve newly freed blocks */
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 49624973eecc..9108eed0ea45 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -941,7 +941,6 @@ xfs_dir_ialloc(
>  	xfs_buf_t	*ialloc_context = NULL;
>  	int		code;
>  	void		*dqinfo;
> -	uint		tflags;
>  
>  	tp = *tpp;
>  	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
> @@ -1000,12 +999,9 @@ xfs_dir_ialloc(
>  		 * and attach it to the next transaction.
>  		 */
>  		dqinfo = NULL;
> -		tflags = 0;
>  		if (tp->t_dqinfo) {
>  			dqinfo = (void *)tp->t_dqinfo;
>  			tp->t_dqinfo = NULL;
> -			tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
> -			tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
>  		}
>  
>  		code = xfs_trans_roll(&tp);
> @@ -1013,10 +1009,8 @@ xfs_dir_ialloc(
>  		/*
>  		 * Re-attach the quota info that we detached from prev trx.
>  		 */
> -		if (dqinfo) {
> +		if (dqinfo)
>  			tp->t_dqinfo = dqinfo;
> -			tp->t_flags |= tflags;
> -		}
>  
>  		if (code) {
>  			xfs_buf_relse(ialloc_context);
> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
> index 1b56065c9ff1..0ebfd7930382 100644
> --- a/fs/xfs/xfs_trans_dquot.c
> +++ b/fs/xfs/xfs_trans_dquot.c
> @@ -84,13 +84,6 @@ xfs_trans_dup_dqinfo(
>  
>  	xfs_trans_alloc_dqinfo(ntp);
>  
> -	/*
> -	 * Because the quota blk reservation is carried forward,
> -	 * it is also necessary to carry forward the DQ_DIRTY flag.
> -	 */
> -	if (otp->t_flags & XFS_TRANS_DQ_DIRTY)
> -		ntp->t_flags |= XFS_TRANS_DQ_DIRTY;
> -
>  	for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
>  		oqa = otp->t_dqinfo->dqs[j];
>  		nqa = ntp->t_dqinfo->dqs[j];
> @@ -270,8 +263,6 @@ xfs_trans_mod_dquot(
>  
>  	if (delta)
>  		trace_xfs_trans_mod_dquot_after(qtrx);
> -
> -	tp->t_flags |= XFS_TRANS_DQ_DIRTY;
>  }
>  
>  
> @@ -348,7 +339,7 @@ xfs_trans_apply_dquot_deltas(
>  	int64_t			totalbdelta;
>  	int64_t			totalrtbdelta;
>  
> -	if (!(tp->t_flags & XFS_TRANS_DQ_DIRTY))
> +	if (!tp->t_dqinfo)
>  		return;
>  
>  	ASSERT(tp->t_dqinfo);
> @@ -490,7 +481,7 @@ xfs_trans_unreserve_and_mod_dquots(
>  	struct xfs_dqtrx	*qtrx, *qa;
>  	bool			locked;
>  
> -	if (!tp->t_dqinfo || !(tp->t_flags & XFS_TRANS_DQ_DIRTY))
> +	if (!tp->t_dqinfo)
>  		return;
>  
>  	for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
> @@ -695,7 +686,6 @@ xfs_trans_dqresv(
>  	 * because we don't have the luxury of a transaction envelope then.
>  	 */
>  	if (tp) {
> -		ASSERT(tp->t_dqinfo);
>  		ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
>  		if (nblks != 0)
>  			xfs_trans_mod_dquot(tp, dqp,
> @@ -749,9 +739,6 @@ xfs_trans_reserve_quota_bydquots(
>  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
>  		return 0;
>  
> -	if (tp && tp->t_dqinfo == NULL)
> -		xfs_trans_alloc_dqinfo(tp);
> -

This also should be a separate patch (or I guess the previous one?)
in which the commit log points out that the allocation is already
covered by the chain xfs_trans_reserve_quota_bydquots ->
xfs_trans_dqresv -> xfs_trans_mod_dquot.

--D

>  	ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
>  
>  	if (udqp) {
> -- 
> 2.20.0
> 

Re: [PATCH v3 4/5] xfs: check tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag

[kaixuxia]

On 2020/10/8 6:04, Darrick J. Wong wrote:
> On Wed, Oct 07, 2020 at 10:51:11PM +0800, xiakaixu1987@gmail.com wrote:
>> From: Kaixu Xia <kaixuxia@tencent.com>
>>
>> Nowadays the only things that the XFS_TRANS_DQ_DIRTY flag seems to do
>> are indicates the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}] values
>> changed and check in xfs_trans_apply_dquot_deltas() and the unreserve
>> variant xfs_trans_unreserve_and_mod_dquots(). Actually, we also can
>> use the tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag, that
>> is to say, we allocate the new tp->t_dqinfo only when the qtrx values
>> changed, so the tp->t_dqinfo value isn't NULL equals the XFS_TRANS_DQ_DIRTY
>> flag is set, we only need to check if tp->t_dqinfo == NULL in
>> xfs_trans_apply_dquot_deltas() and its unreserve variant to determine
>> whether lock all of the dquots and join them to the transaction.
>>
>> Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
>> ---
>>  fs/xfs/libxfs/xfs_shared.h |  1 -
>>  fs/xfs/xfs_inode.c         |  8 +-------
>>  fs/xfs/xfs_trans_dquot.c   | 17 ++---------------
>>  3 files changed, 3 insertions(+), 23 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
>> index c795ae47b3c9..8c61a461bf7b 100644
>> --- a/fs/xfs/libxfs/xfs_shared.h
>> +++ b/fs/xfs/libxfs/xfs_shared.h
>> @@ -62,7 +62,6 @@ void	xfs_log_get_max_trans_res(struct xfs_mount *mp,
>>  #define	XFS_TRANS_SB_DIRTY	0x02	/* superblock is modified */
>>  #define	XFS_TRANS_PERM_LOG_RES	0x04	/* xact took a permanent log res */
>>  #define	XFS_TRANS_SYNC		0x08	/* make commit synchronous */
>> -#define XFS_TRANS_DQ_DIRTY	0x10	/* at least one dquot in trx dirty */
>>  #define XFS_TRANS_RESERVE	0x20    /* OK to use reserved data blocks */
>>  #define XFS_TRANS_NO_WRITECOUNT 0x40	/* do not elevate SB writecount */
>>  #define XFS_TRANS_RES_FDBLKS	0x80	/* reserve newly freed blocks */
>> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
>> index 49624973eecc..9108eed0ea45 100644
>> --- a/fs/xfs/xfs_inode.c
>> +++ b/fs/xfs/xfs_inode.c
>> @@ -941,7 +941,6 @@ xfs_dir_ialloc(
>>  	xfs_buf_t	*ialloc_context = NULL;
>>  	int		code;
>>  	void		*dqinfo;
>> -	uint		tflags;
>>  
>>  	tp = *tpp;
>>  	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
>> @@ -1000,12 +999,9 @@ xfs_dir_ialloc(
>>  		 * and attach it to the next transaction.
>>  		 */
>>  		dqinfo = NULL;
>> -		tflags = 0;
>>  		if (tp->t_dqinfo) {
>>  			dqinfo = (void *)tp->t_dqinfo;
>>  			tp->t_dqinfo = NULL;
>> -			tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
>> -			tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
>>  		}
>>  
>>  		code = xfs_trans_roll(&tp);
>> @@ -1013,10 +1009,8 @@ xfs_dir_ialloc(
>>  		/*
>>  		 * Re-attach the quota info that we detached from prev trx.
>>  		 */
>> -		if (dqinfo) {
>> +		if (dqinfo)
>>  			tp->t_dqinfo = dqinfo;
>> -			tp->t_flags |= tflags;
>> -		}
>>  
>>  		if (code) {
>>  			xfs_buf_relse(ialloc_context);
>> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
>> index 1b56065c9ff1..0ebfd7930382 100644
>> --- a/fs/xfs/xfs_trans_dquot.c
>> +++ b/fs/xfs/xfs_trans_dquot.c
>> @@ -84,13 +84,6 @@ xfs_trans_dup_dqinfo(
>>  
>>  	xfs_trans_alloc_dqinfo(ntp);
>>  
>> -	/*
>> -	 * Because the quota blk reservation is carried forward,
>> -	 * it is also necessary to carry forward the DQ_DIRTY flag.
>> -	 */
>> -	if (otp->t_flags & XFS_TRANS_DQ_DIRTY)
>> -		ntp->t_flags |= XFS_TRANS_DQ_DIRTY;
>> -
>>  	for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
>>  		oqa = otp->t_dqinfo->dqs[j];
>>  		nqa = ntp->t_dqinfo->dqs[j];
>> @@ -270,8 +263,6 @@ xfs_trans_mod_dquot(
>>  
>>  	if (delta)
>>  		trace_xfs_trans_mod_dquot_after(qtrx);
>> -
>> -	tp->t_flags |= XFS_TRANS_DQ_DIRTY;
>>  }
>>  
>>  
>> @@ -348,7 +339,7 @@ xfs_trans_apply_dquot_deltas(
>>  	int64_t			totalbdelta;
>>  	int64_t			totalrtbdelta;
>>  
>> -	if (!(tp->t_flags & XFS_TRANS_DQ_DIRTY))
>> +	if (!tp->t_dqinfo)
>>  		return;
>>  
>>  	ASSERT(tp->t_dqinfo);
>> @@ -490,7 +481,7 @@ xfs_trans_unreserve_and_mod_dquots(
>>  	struct xfs_dqtrx	*qtrx, *qa;
>>  	bool			locked;
>>  
>> -	if (!tp->t_dqinfo || !(tp->t_flags & XFS_TRANS_DQ_DIRTY))
>> +	if (!tp->t_dqinfo)
>>  		return;
>>  
>>  	for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
>> @@ -695,7 +686,6 @@ xfs_trans_dqresv(
>>  	 * because we don't have the luxury of a transaction envelope then.
>>  	 */
>>  	if (tp) {
>> -		ASSERT(tp->t_dqinfo);
>>  		ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
>>  		if (nblks != 0)
>>  			xfs_trans_mod_dquot(tp, dqp,
>> @@ -749,9 +739,6 @@ xfs_trans_reserve_quota_bydquots(
>>  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
>>  		return 0;
>>  
>> -	if (tp && tp->t_dqinfo == NULL)
>> -		xfs_trans_alloc_dqinfo(tp);
>> -
> 
> This also should be a separate patch (or I guess the previous one?)
> in which the commit log points out that the allocation is already
> covered by the chain xfs_trans_reserve_quota_bydquots ->
> xfs_trans_dqresv -> xfs_trans_mod_dquot.

Yeah, make more sense, I'll follow it in the next version.

Thanks,
Kaixu
> 
> --D
> 
>>  	ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
>>  
>>  	if (udqp) {
>> -- 
>> 2.20.0
>>

-- 
kaixuxia

[PATCH v3 5/5] xfs: directly return if the delta equal to zero

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@tencent.com>

The xfs_trans_mod_dquot() function will allocate new tp->t_dqinfo if it is
NULL and make the changes in the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}].
Nowadays seems none of the callers want to join the dquots to the
transaction and push them to device when the delta is zero. Actually,
most of time the caller would check the delta and go on only when the
delta value is not zero, so we should bail out when it is zero.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
---
 fs/xfs/xfs_trans_dquot.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
index 0ebfd7930382..3e37501791bf 100644
--- a/fs/xfs/xfs_trans_dquot.c
+++ b/fs/xfs/xfs_trans_dquot.c
@@ -194,6 +194,9 @@ xfs_trans_mod_dquot(
 	ASSERT(XFS_IS_QUOTA_RUNNING(tp->t_mountp));
 	qtrx = NULL;
 
+	if (!delta)
+		return;
+
 	if (tp->t_dqinfo == NULL)
 		xfs_trans_alloc_dqinfo(tp);
 	/*
@@ -205,10 +208,8 @@ xfs_trans_mod_dquot(
 	if (qtrx->qt_dquot == NULL)
 		qtrx->qt_dquot = dqp;
 
-	if (delta) {
-		trace_xfs_trans_mod_dquot_before(qtrx);
-		trace_xfs_trans_mod_dquot(tp, dqp, field, delta);
-	}
+	trace_xfs_trans_mod_dquot_before(qtrx);
+	trace_xfs_trans_mod_dquot(tp, dqp, field, delta);
 
 	switch (field) {
 	/* regular disk blk reservation */
@@ -261,8 +262,7 @@ xfs_trans_mod_dquot(
 		ASSERT(0);
 	}
 
-	if (delta)
-		trace_xfs_trans_mod_dquot_after(qtrx);
+	trace_xfs_trans_mod_dquot_after(qtrx);
 }
 
 
-- 
2.20.0

Re: [PATCH v3 5/5] xfs: directly return if the delta equal to zero

[Darrick J. Wong]

On Wed, Oct 07, 2020 at 10:51:12PM +0800, xiakaixu1987@gmail.com wrote:
> From: Kaixu Xia <kaixuxia@tencent.com>
> 
> The xfs_trans_mod_dquot() function will allocate new tp->t_dqinfo if it is
> NULL and make the changes in the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}].
> Nowadays seems none of the callers want to join the dquots to the
> transaction and push them to device when the delta is zero. Actually,
> most of time the caller would check the delta and go on only when the
> delta value is not zero, so we should bail out when it is zero.
> 
> Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>

Looks decent now; as far as I can tell, nothing will trip over null
t_dqinfo if we're not actually changing the dquots...

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_trans_dquot.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
> index 0ebfd7930382..3e37501791bf 100644
> --- a/fs/xfs/xfs_trans_dquot.c
> +++ b/fs/xfs/xfs_trans_dquot.c
> @@ -194,6 +194,9 @@ xfs_trans_mod_dquot(
>  	ASSERT(XFS_IS_QUOTA_RUNNING(tp->t_mountp));
>  	qtrx = NULL;
>  
> +	if (!delta)
> +		return;
> +
>  	if (tp->t_dqinfo == NULL)
>  		xfs_trans_alloc_dqinfo(tp);
>  	/*
> @@ -205,10 +208,8 @@ xfs_trans_mod_dquot(
>  	if (qtrx->qt_dquot == NULL)
>  		qtrx->qt_dquot = dqp;
>  
> -	if (delta) {
> -		trace_xfs_trans_mod_dquot_before(qtrx);
> -		trace_xfs_trans_mod_dquot(tp, dqp, field, delta);
> -	}
> +	trace_xfs_trans_mod_dquot_before(qtrx);
> +	trace_xfs_trans_mod_dquot(tp, dqp, field, delta);
>  
>  	switch (field) {
>  	/* regular disk blk reservation */
> @@ -261,8 +262,7 @@ xfs_trans_mod_dquot(
>  		ASSERT(0);
>  	}
>  
> -	if (delta)
> -		trace_xfs_trans_mod_dquot_after(qtrx);
> +	trace_xfs_trans_mod_dquot_after(qtrx);
>  }
>  
>  
> -- 
> 2.20.0
>