[PATCH 05/14] xfs: refactor quota expiration timer modification

From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org
Subject: [PATCH 05/14] xfs: refactor quota expiration timer modification
Date: Tue, 31 Dec 2019 17:11:33 -0800	[thread overview]
Message-ID: <157784109369.1364230.637677553755124721.stgit@magnolia> (raw)
In-Reply-To: <157784106066.1364230.569420432829402226.stgit@magnolia>

From: Darrick J. Wong <darrick.wong@oracle.com>

Define explicit limits on the range of quota grace period expiration
timeouts and refactor the code that modifies the timeouts into helpers
that clamp the values appropriately.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_format.h |   22 ++++++++++++++++++++++
 fs/xfs/xfs_dquot.c         |   42 ++++++++++++++++++++++++++++++++++++------
 fs/xfs/xfs_ondisk.h        |    2 ++
 3 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 82b15832ba32..95761b38fe86 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1180,6 +1180,28 @@ static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
 #define XFS_DQUOT_MAGIC		0x4451		/* 'DQ' */
 #define XFS_DQUOT_VERSION	(uint8_t)0x01	/* latest version number */
 
+/*
+ * XFS Quota Timers
+ * ================
+ *
+ * Quota grace period expiration timers are an unsigned 32-bit seconds counter;
+ * time zero is the Unix epoch, Jan  1 00:00:01 UTC 1970.  An expiration value
+ * of zero means that the quota limit has not been reached, and therefore no
+ * expiration has been set.
+ */
+
+/*
+ * Smallest possible quota expiration with traditional timestamps, which is
+ * Jan  1 00:00:01 UTC 1970.
+ */
+#define XFS_DQ_TIMEOUT_MIN	((int64_t)1)
+
+/*
+ * Largest possible quota expiration with traditional timestamps, which is
+ * Feb  7 06:28:15 UTC 2106.
+ */
+#define XFS_DQ_TIMEOUT_MAX	((int64_t)U32_MAX)
+
 /*
  * This is the main portion of the on-disk representation of quota
  * information for a user. This is the q_core of the struct xfs_dquot that
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index ae7bb6361a99..44bae5f16b55 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -113,6 +113,36 @@ xfs_quota_exceeded(
 	return *hardlimit && count > be64_to_cpup(hardlimit);
 }
 
+/*
+ * Clamp a quota grace period expiration timer to the range that we support.
+ */
+static inline time64_t
+xfs_dquot_clamp_timer(
+	time64_t			timer)
+{
+	return clamp_t(time64_t, timer, XFS_DQ_TIMEOUT_MIN, XFS_DQ_TIMEOUT_MAX);
+}
+
+/* Set a quota grace period expiration timer. */
+static inline void
+xfs_quota_set_timer(
+	__be32			*dtimer,
+	time_t			limit)
+{
+	time64_t		new_timeout;
+
+	new_timeout = xfs_dquot_clamp_timer(get_seconds() + limit);
+	*dtimer = cpu_to_be32(new_timeout);
+}
+
+/* Clear a quota grace period expiration timer. */
+static inline void
+xfs_quota_clear_timer(
+	__be32			*dtimer)
+{
+	*dtimer = cpu_to_be32(0);
+}
+
 /*
  * Check the limits and timers of a dquot and start or reset timers
  * if necessary.
@@ -152,14 +182,14 @@ xfs_qm_adjust_dqtimers(
 			&d->d_blk_softlimit, &d->d_blk_hardlimit);
 	if (!d->d_btimer) {
 		if (over) {
-			d->d_btimer = cpu_to_be32(get_seconds() +
+			xfs_quota_set_timer(&d->d_btimer,
 					mp->m_quotainfo->qi_btimelimit);
 		} else {
 			d->d_bwarns = 0;
 		}
 	} else {
 		if (!over) {
-			d->d_btimer = 0;
+			xfs_quota_clear_timer(&d->d_btimer);
 		}
 	}
 
@@ -167,14 +197,14 @@ xfs_qm_adjust_dqtimers(
 			&d->d_ino_softlimit, &d->d_ino_hardlimit);
 	if (!d->d_itimer) {
 		if (over) {
-			d->d_itimer = cpu_to_be32(get_seconds() +
+			xfs_quota_set_timer(&d->d_itimer,
 					mp->m_quotainfo->qi_itimelimit);
 		} else {
 			d->d_iwarns = 0;
 		}
 	} else {
 		if (!over) {
-			d->d_itimer = 0;
+			xfs_quota_clear_timer(&d->d_itimer);
 		}
 	}
 
@@ -182,14 +212,14 @@ xfs_qm_adjust_dqtimers(
 			&d->d_rtb_softlimit, &d->d_rtb_hardlimit);
 	if (!d->d_rtbtimer) {
 		if (over) {
-			d->d_rtbtimer = cpu_to_be32(get_seconds() +
+			xfs_quota_set_timer(&d->d_rtbtimer,
 					mp->m_quotainfo->qi_rtbtimelimit);
 		} else {
 			d->d_rtbwarns = 0;
 		}
 	} else {
 		if (!over) {
-			d->d_rtbtimer = 0;
+			xfs_quota_clear_timer(&d->d_rtbtimer);
 		}
 	}
 }
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index f67f3645efcd..52dc5326b7bf 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -25,6 +25,8 @@ xfs_check_ondisk_structs(void)
 	/* make sure timestamp limits are correct */
 	XFS_CHECK_VALUE(XFS_INO_TIME_MIN, 			-2147483648LL);
 	XFS_CHECK_VALUE(XFS_INO_TIME_MAX,			2147483647LL);
+	XFS_CHECK_VALUE(XFS_DQ_TIMEOUT_MIN,			1LL);
+	XFS_CHECK_VALUE(XFS_DQ_TIMEOUT_MAX,			4294967295LL);
 
 	/* ag/file structures */
 	XFS_CHECK_STRUCT_SIZE(struct xfs_acl,			4);

