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* [PATCH 1/2] xfs: don't take m_sb_lock in xfs_fs_statfs
@ 2025-01-13  4:32 Christoph Hellwig
  2025-01-13  4:32 ` [PATCH 2/2] xfs: refactor xfs_fs_statfs Christoph Hellwig
  2025-01-14 10:30 ` [PATCH 1/2] xfs: don't take m_sb_lock in xfs_fs_statfs Carlos Maiolino
  0 siblings, 2 replies; 4+ messages in thread
From: Christoph Hellwig @ 2025-01-13  4:32 UTC (permalink / raw)
  To: cem; +Cc: djwong, linux-xfs

The only non-constant value read under m_sb_lock in xfs_fs_statfs is
sb_dblocks, and it could become stale right after dropping the lock
anyway.  Remove the thus pointless lock section.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/xfs/xfs_super.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 7c3f996cd39e..20cc00b992a6 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -850,11 +850,13 @@ xfs_fs_statfs(
 	ifree = percpu_counter_sum(&mp->m_ifree);
 	fdblocks = percpu_counter_sum(&mp->m_fdblocks);
 
-	spin_lock(&mp->m_sb_lock);
 	statp->f_bsize = sbp->sb_blocksize;
 	lsize = sbp->sb_logstart ? sbp->sb_logblocks : 0;
+	/*
+	 * sb_dblocks can change during growfs, but nothing cares about reporting
+	 * the old or new value during growfs.
+	 */
 	statp->f_blocks = sbp->sb_dblocks - lsize;
-	spin_unlock(&mp->m_sb_lock);
 
 	/* make sure statp->f_bfree does not underflow */
 	statp->f_bfree = max_t(int64_t, 0,
-- 
2.45.2


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH 2/2] xfs: refactor xfs_fs_statfs
  2025-01-13  4:32 [PATCH 1/2] xfs: don't take m_sb_lock in xfs_fs_statfs Christoph Hellwig
@ 2025-01-13  4:32 ` Christoph Hellwig
  2025-01-13  5:04   ` Darrick J. Wong
  2025-01-14 10:30 ` [PATCH 1/2] xfs: don't take m_sb_lock in xfs_fs_statfs Carlos Maiolino
  1 sibling, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2025-01-13  4:32 UTC (permalink / raw)
  To: cem; +Cc: djwong, linux-xfs

Split out helpers for data, rt data and inode related information, and
assigning f_bavail once instead of in three places.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_qm_bhv.c |   1 -
 fs/xfs/xfs_super.c  | 132 ++++++++++++++++++++++++++------------------
 2 files changed, 78 insertions(+), 55 deletions(-)

diff --git a/fs/xfs/xfs_qm_bhv.c b/fs/xfs/xfs_qm_bhv.c
index db5b8afd9d1b..37f1230e7584 100644
--- a/fs/xfs/xfs_qm_bhv.c
+++ b/fs/xfs/xfs_qm_bhv.c
@@ -40,7 +40,6 @@ xfs_fill_statvfs_from_dquot(
 
 		statp->f_blocks = min(statp->f_blocks, limit);
 		statp->f_bfree = min(statp->f_bfree, remaining);
-		statp->f_bavail = min(statp->f_bavail, remaining);
 	}
 
 	limit = dqp->q_ino.softlimit ?
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 20cc00b992a6..809ac6d1813c 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -819,81 +819,105 @@ xfs_fs_sync_fs(
 	return 0;
 }
 
-STATIC int
-xfs_fs_statfs(
-	struct dentry		*dentry,
-	struct kstatfs		*statp)
+static xfs_extlen_t
+xfs_internal_log_size(
+	struct xfs_mount	*mp)
 {
-	struct xfs_mount	*mp = XFS_M(dentry->d_sb);
-	xfs_sb_t		*sbp = &mp->m_sb;
-	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
-	uint64_t		fakeinos, id;
-	uint64_t		icount;
-	uint64_t		ifree;
-	uint64_t		fdblocks;
-	xfs_extlen_t		lsize;
-	int64_t			ffree;
-
-	/*
-	 * Expedite background inodegc but don't wait. We do not want to block
-	 * here waiting hours for a billion extent file to be truncated.
-	 */
-	xfs_inodegc_push(mp);
-
-	statp->f_type = XFS_SUPER_MAGIC;
-	statp->f_namelen = MAXNAMELEN - 1;
-
-	id = huge_encode_dev(mp->m_ddev_targp->bt_dev);
-	statp->f_fsid = u64_to_fsid(id);
+	if (!mp->m_sb.sb_logstart)
+		return 0;
+	return mp->m_sb.sb_logblocks;
+}
 
-	icount = percpu_counter_sum(&mp->m_icount);
-	ifree = percpu_counter_sum(&mp->m_ifree);
-	fdblocks = percpu_counter_sum(&mp->m_fdblocks);
+static void
+xfs_statfs_data(
+	struct xfs_mount	*mp,
+	struct kstatfs		*st)
+{
+	int64_t			fdblocks =
+		percpu_counter_sum(&mp->m_fdblocks);
 
-	statp->f_bsize = sbp->sb_blocksize;
-	lsize = sbp->sb_logstart ? sbp->sb_logblocks : 0;
+	/* make sure st->f_bfree does not underflow */
+	st->f_bfree = max(0LL, fdblocks - xfs_fdblocks_unavailable(mp));
 	/*
 	 * sb_dblocks can change during growfs, but nothing cares about reporting
 	 * the old or new value during growfs.
 	 */
-	statp->f_blocks = sbp->sb_dblocks - lsize;
+	st->f_blocks = mp->m_sb.sb_dblocks - xfs_internal_log_size(mp);
+}
+
+/*
+ * When stat(v)fs is called on a file with the realtime bit set or a directory
+ * with the rtinherit bit, report freespace information for the RT device
+ * instead of the main data device.
+ */
+static void
+xfs_statfs_rt(
+	struct xfs_mount	*mp,
+	struct kstatfs		*st)
+{
+	st->f_bfree = xfs_rtbxlen_to_blen(mp,
+			percpu_counter_sum_positive(&mp->m_frextents));
+	st->f_blocks = mp->m_sb.sb_rblocks;
+}
 
-	/* make sure statp->f_bfree does not underflow */
-	statp->f_bfree = max_t(int64_t, 0,
-				fdblocks - xfs_fdblocks_unavailable(mp));
-	statp->f_bavail = statp->f_bfree;
+static void
+xfs_statfs_inodes(
+	struct xfs_mount	*mp,
+	struct kstatfs		*st)
+{
+	uint64_t		icount = percpu_counter_sum(&mp->m_icount);
+	uint64_t		ifree = percpu_counter_sum(&mp->m_ifree);
+	uint64_t		fakeinos = XFS_FSB_TO_INO(mp, st->f_bfree);
 
-	fakeinos = XFS_FSB_TO_INO(mp, statp->f_bfree);
-	statp->f_files = min(icount + fakeinos, (uint64_t)XFS_MAXINUMBER);
+	st->f_files = min(icount + fakeinos, (uint64_t)XFS_MAXINUMBER);
 	if (M_IGEO(mp)->maxicount)
-		statp->f_files = min_t(typeof(statp->f_files),
-					statp->f_files,
+		st->f_files = min_t(typeof(st->f_files), st->f_files,
 					M_IGEO(mp)->maxicount);
 
 	/* If sb_icount overshot maxicount, report actual allocation */
-	statp->f_files = max_t(typeof(statp->f_files),
-					statp->f_files,
-					sbp->sb_icount);
+	st->f_files = max_t(typeof(st->f_files), st->f_files,
+			mp->m_sb.sb_icount);
 
-	/* make sure statp->f_ffree does not underflow */
-	ffree = statp->f_files - (icount - ifree);
-	statp->f_ffree = max_t(int64_t, ffree, 0);
+	/* Make sure st->f_ffree does not underflow */
+	st->f_ffree = max_t(int64_t, 0, st->f_files - (icount - ifree));
+}
 
-	if (XFS_IS_REALTIME_MOUNT(mp) &&
-	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME))) {
-		s64	freertx;
+STATIC int
+xfs_fs_statfs(
+	struct dentry		*dentry,
+	struct kstatfs		*st)
+{
+	struct xfs_mount	*mp = XFS_M(dentry->d_sb);
+	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
 
-		statp->f_blocks = sbp->sb_rblocks;
-		freertx = percpu_counter_sum_positive(&mp->m_frextents);
-		statp->f_bavail = statp->f_bfree =
-			xfs_rtbxlen_to_blen(mp, freertx);
-	}
+	/*
+	 * Expedite background inodegc but don't wait. We do not want to block
+	 * here waiting hours for a billion extent file to be truncated.
+	 */
+	xfs_inodegc_push(mp);
+
+	st->f_type = XFS_SUPER_MAGIC;
+	st->f_namelen = MAXNAMELEN - 1;
+	st->f_bsize = mp->m_sb.sb_blocksize;
+	st->f_fsid = u64_to_fsid(huge_encode_dev(mp->m_ddev_targp->bt_dev));
+
+	xfs_statfs_data(mp, st);
+	xfs_statfs_inodes(mp, st);
+
+	if (XFS_IS_REALTIME_MOUNT(mp) &&
+	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME)))
+		xfs_statfs_rt(mp, st);
 
 	if ((ip->i_diflags & XFS_DIFLAG_PROJINHERIT) &&
 	    ((mp->m_qflags & (XFS_PQUOTA_ACCT|XFS_PQUOTA_ENFD))) ==
 			      (XFS_PQUOTA_ACCT|XFS_PQUOTA_ENFD))
-		xfs_qm_statvfs(ip, statp);
+		xfs_qm_statvfs(ip, st);
 
+	/*
+	 * XFS does not distinguish between blocks available to privileged and
+	 * unprivileged users.
+	 */
+	st->f_bavail = st->f_bfree;
 	return 0;
 }
 
-- 
2.45.2


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] xfs: refactor xfs_fs_statfs
  2025-01-13  4:32 ` [PATCH 2/2] xfs: refactor xfs_fs_statfs Christoph Hellwig
@ 2025-01-13  5:04   ` Darrick J. Wong
  0 siblings, 0 replies; 4+ messages in thread
From: Darrick J. Wong @ 2025-01-13  5:04 UTC (permalink / raw)
  To: Christoph Hellwig; +Cc: cem, linux-xfs

On Mon, Jan 13, 2025 at 05:32:59AM +0100, Christoph Hellwig wrote:
> Split out helpers for data, rt data and inode related information, and
> assigning f_bavail once instead of in three places.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good now,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_qm_bhv.c |   1 -
>  fs/xfs/xfs_super.c  | 132 ++++++++++++++++++++++++++------------------
>  2 files changed, 78 insertions(+), 55 deletions(-)
> 
> diff --git a/fs/xfs/xfs_qm_bhv.c b/fs/xfs/xfs_qm_bhv.c
> index db5b8afd9d1b..37f1230e7584 100644
> --- a/fs/xfs/xfs_qm_bhv.c
> +++ b/fs/xfs/xfs_qm_bhv.c
> @@ -40,7 +40,6 @@ xfs_fill_statvfs_from_dquot(
>  
>  		statp->f_blocks = min(statp->f_blocks, limit);
>  		statp->f_bfree = min(statp->f_bfree, remaining);
> -		statp->f_bavail = min(statp->f_bavail, remaining);
>  	}
>  
>  	limit = dqp->q_ino.softlimit ?
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 20cc00b992a6..809ac6d1813c 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -819,81 +819,105 @@ xfs_fs_sync_fs(
>  	return 0;
>  }
>  
> -STATIC int
> -xfs_fs_statfs(
> -	struct dentry		*dentry,
> -	struct kstatfs		*statp)
> +static xfs_extlen_t
> +xfs_internal_log_size(
> +	struct xfs_mount	*mp)
>  {
> -	struct xfs_mount	*mp = XFS_M(dentry->d_sb);
> -	xfs_sb_t		*sbp = &mp->m_sb;
> -	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
> -	uint64_t		fakeinos, id;
> -	uint64_t		icount;
> -	uint64_t		ifree;
> -	uint64_t		fdblocks;
> -	xfs_extlen_t		lsize;
> -	int64_t			ffree;
> -
> -	/*
> -	 * Expedite background inodegc but don't wait. We do not want to block
> -	 * here waiting hours for a billion extent file to be truncated.
> -	 */
> -	xfs_inodegc_push(mp);
> -
> -	statp->f_type = XFS_SUPER_MAGIC;
> -	statp->f_namelen = MAXNAMELEN - 1;
> -
> -	id = huge_encode_dev(mp->m_ddev_targp->bt_dev);
> -	statp->f_fsid = u64_to_fsid(id);
> +	if (!mp->m_sb.sb_logstart)
> +		return 0;
> +	return mp->m_sb.sb_logblocks;
> +}
>  
> -	icount = percpu_counter_sum(&mp->m_icount);
> -	ifree = percpu_counter_sum(&mp->m_ifree);
> -	fdblocks = percpu_counter_sum(&mp->m_fdblocks);
> +static void
> +xfs_statfs_data(
> +	struct xfs_mount	*mp,
> +	struct kstatfs		*st)
> +{
> +	int64_t			fdblocks =
> +		percpu_counter_sum(&mp->m_fdblocks);
>  
> -	statp->f_bsize = sbp->sb_blocksize;
> -	lsize = sbp->sb_logstart ? sbp->sb_logblocks : 0;
> +	/* make sure st->f_bfree does not underflow */
> +	st->f_bfree = max(0LL, fdblocks - xfs_fdblocks_unavailable(mp));
>  	/*
>  	 * sb_dblocks can change during growfs, but nothing cares about reporting
>  	 * the old or new value during growfs.
>  	 */
> -	statp->f_blocks = sbp->sb_dblocks - lsize;
> +	st->f_blocks = mp->m_sb.sb_dblocks - xfs_internal_log_size(mp);
> +}
> +
> +/*
> + * When stat(v)fs is called on a file with the realtime bit set or a directory
> + * with the rtinherit bit, report freespace information for the RT device
> + * instead of the main data device.
> + */
> +static void
> +xfs_statfs_rt(
> +	struct xfs_mount	*mp,
> +	struct kstatfs		*st)
> +{
> +	st->f_bfree = xfs_rtbxlen_to_blen(mp,
> +			percpu_counter_sum_positive(&mp->m_frextents));
> +	st->f_blocks = mp->m_sb.sb_rblocks;
> +}
>  
> -	/* make sure statp->f_bfree does not underflow */
> -	statp->f_bfree = max_t(int64_t, 0,
> -				fdblocks - xfs_fdblocks_unavailable(mp));
> -	statp->f_bavail = statp->f_bfree;
> +static void
> +xfs_statfs_inodes(
> +	struct xfs_mount	*mp,
> +	struct kstatfs		*st)
> +{
> +	uint64_t		icount = percpu_counter_sum(&mp->m_icount);
> +	uint64_t		ifree = percpu_counter_sum(&mp->m_ifree);
> +	uint64_t		fakeinos = XFS_FSB_TO_INO(mp, st->f_bfree);
>  
> -	fakeinos = XFS_FSB_TO_INO(mp, statp->f_bfree);
> -	statp->f_files = min(icount + fakeinos, (uint64_t)XFS_MAXINUMBER);
> +	st->f_files = min(icount + fakeinos, (uint64_t)XFS_MAXINUMBER);
>  	if (M_IGEO(mp)->maxicount)
> -		statp->f_files = min_t(typeof(statp->f_files),
> -					statp->f_files,
> +		st->f_files = min_t(typeof(st->f_files), st->f_files,
>  					M_IGEO(mp)->maxicount);
>  
>  	/* If sb_icount overshot maxicount, report actual allocation */
> -	statp->f_files = max_t(typeof(statp->f_files),
> -					statp->f_files,
> -					sbp->sb_icount);
> +	st->f_files = max_t(typeof(st->f_files), st->f_files,
> +			mp->m_sb.sb_icount);
>  
> -	/* make sure statp->f_ffree does not underflow */
> -	ffree = statp->f_files - (icount - ifree);
> -	statp->f_ffree = max_t(int64_t, ffree, 0);
> +	/* Make sure st->f_ffree does not underflow */
> +	st->f_ffree = max_t(int64_t, 0, st->f_files - (icount - ifree));
> +}
>  
> -	if (XFS_IS_REALTIME_MOUNT(mp) &&
> -	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME))) {
> -		s64	freertx;
> +STATIC int
> +xfs_fs_statfs(
> +	struct dentry		*dentry,
> +	struct kstatfs		*st)
> +{
> +	struct xfs_mount	*mp = XFS_M(dentry->d_sb);
> +	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
>  
> -		statp->f_blocks = sbp->sb_rblocks;
> -		freertx = percpu_counter_sum_positive(&mp->m_frextents);
> -		statp->f_bavail = statp->f_bfree =
> -			xfs_rtbxlen_to_blen(mp, freertx);
> -	}
> +	/*
> +	 * Expedite background inodegc but don't wait. We do not want to block
> +	 * here waiting hours for a billion extent file to be truncated.
> +	 */
> +	xfs_inodegc_push(mp);
> +
> +	st->f_type = XFS_SUPER_MAGIC;
> +	st->f_namelen = MAXNAMELEN - 1;
> +	st->f_bsize = mp->m_sb.sb_blocksize;
> +	st->f_fsid = u64_to_fsid(huge_encode_dev(mp->m_ddev_targp->bt_dev));
> +
> +	xfs_statfs_data(mp, st);
> +	xfs_statfs_inodes(mp, st);
> +
> +	if (XFS_IS_REALTIME_MOUNT(mp) &&
> +	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME)))
> +		xfs_statfs_rt(mp, st);
>  
>  	if ((ip->i_diflags & XFS_DIFLAG_PROJINHERIT) &&
>  	    ((mp->m_qflags & (XFS_PQUOTA_ACCT|XFS_PQUOTA_ENFD))) ==
>  			      (XFS_PQUOTA_ACCT|XFS_PQUOTA_ENFD))
> -		xfs_qm_statvfs(ip, statp);
> +		xfs_qm_statvfs(ip, st);
>  
> +	/*
> +	 * XFS does not distinguish between blocks available to privileged and
> +	 * unprivileged users.
> +	 */
> +	st->f_bavail = st->f_bfree;
>  	return 0;
>  }
>  
> -- 
> 2.45.2
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 1/2] xfs: don't take m_sb_lock in xfs_fs_statfs
  2025-01-13  4:32 [PATCH 1/2] xfs: don't take m_sb_lock in xfs_fs_statfs Christoph Hellwig
  2025-01-13  4:32 ` [PATCH 2/2] xfs: refactor xfs_fs_statfs Christoph Hellwig
@ 2025-01-14 10:30 ` Carlos Maiolino
  1 sibling, 0 replies; 4+ messages in thread
From: Carlos Maiolino @ 2025-01-14 10:30 UTC (permalink / raw)
  To: Christoph Hellwig; +Cc: djwong, linux-xfs

On Mon, 13 Jan 2025 05:32:58 +0100, Christoph Hellwig wrote:
> The only non-constant value read under m_sb_lock in xfs_fs_statfs is
> sb_dblocks, and it could become stale right after dropping the lock
> anyway.  Remove the thus pointless lock section.
> 
> 

Applied to for-next, thanks!

[1/2] xfs: don't take m_sb_lock in xfs_fs_statfs
      commit: 72843ca62417a0587ca98791b172e4c3b3f8d3a8
[2/2] xfs: refactor xfs_fs_statfs
      commit: dd324cb79e54d3a61621f09c346ee050315a4d2e

Best regards,
-- 
Carlos Maiolino <cem@kernel.org>


^ permalink raw reply	[flat|nested] 4+ messages in thread

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