[PATCH 02/11] 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, amir73il@gmail.com, sandeen@sandeen.net
Subject: [PATCH 02/11] xfs: refactor quota expiration timer modification
Date: Mon, 17 Aug 2020 15:57:00 -0700	[thread overview]
Message-ID: <159770502083.3956827.8660123941779980742.stgit@magnolia> (raw)
In-Reply-To: <159770500809.3956827.8869892960975362931.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         |   13 ++++++++++++-
 fs/xfs/xfs_dquot.h         |    2 ++
 fs/xfs/xfs_ondisk.h        |    2 ++
 fs/xfs/xfs_qm_syscalls.c   |    9 +++++++--
 5 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index b1b8a5c05cea..ef36978239ac 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1197,6 +1197,28 @@ static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
 
 #define XFS_DQTYPE_ANY		(XFS_DQTYPE_REC_MASK)
 
+/*
+ * 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.  We pad this with some more expansion room to construct the on
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index bcd73b9c2994..2425b1c30d11 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -98,6 +98,16 @@ xfs_qm_adjust_dqlimits(
 		xfs_dquot_set_prealloc_limits(dq);
 }
 
+/* Set the expiration time of a quota's grace period. */
+void
+xfs_dquot_set_timeout(
+	time64_t		*timer,
+	time64_t		value)
+{
+	*timer = clamp_t(time64_t, value, XFS_DQ_TIMEOUT_MIN,
+					  XFS_DQ_TIMEOUT_MAX);
+}
+
 /*
  * Determine if this quota counter is over either limit and set the quota
  * timers as appropriate.
@@ -112,7 +122,8 @@ xfs_qm_adjust_res_timer(
 	if ((res->softlimit && res->count > res->softlimit) ||
 	    (res->hardlimit && res->count > res->hardlimit)) {
 		if (res->timer == 0)
-			res->timer = ktime_get_real_seconds() + qlim->time;
+			xfs_dquot_set_timeout(&res->timer,
+					ktime_get_real_seconds() + qlim->time);
 	} else {
 		if (res->timer == 0)
 			res->warnings = 0;
diff --git a/fs/xfs/xfs_dquot.h b/fs/xfs/xfs_dquot.h
index 282a65da93c7..11bd0ee9b0fa 100644
--- a/fs/xfs/xfs_dquot.h
+++ b/fs/xfs/xfs_dquot.h
@@ -237,4 +237,6 @@ typedef int (*xfs_qm_dqiterate_fn)(struct xfs_dquot *dq,
 int xfs_qm_dqiterate(struct xfs_mount *mp, xfs_dqtype_t type,
 		xfs_qm_dqiterate_fn iter_fn, void *priv);
 
+void xfs_dquot_set_timeout(time64_t *timer, time64_t limit);
+
 #endif /* __XFS_DQUOT_H__ */
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 48a64fa49f91..38ccffcf3336 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -25,6 +25,8 @@ xfs_check_limits(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);
 }
 
 static inline void __init
diff --git a/fs/xfs/xfs_qm_syscalls.c b/fs/xfs/xfs_qm_syscalls.c
index 1c542b4a5220..b16d533a6feb 100644
--- a/fs/xfs/xfs_qm_syscalls.c
+++ b/fs/xfs/xfs_qm_syscalls.c
@@ -483,9 +483,14 @@ xfs_setqlim_timer(
 	struct xfs_quota_limits	*qlim,
 	s64			timer)
 {
-	res->timer = timer;
-	if (qlim)
+	if (qlim) {
+		/* Set the length of the default grace period. */
+		res->timer = timer;
 		qlim->time = timer;
+	} else {
+		/* Set the grace period expiration on a quota. */
+		xfs_dquot_set_timeout(&res->timer, timer);
+	}
 }
 
 /*

