xfs: refactor quota expiration timer modification

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.  Note that we'll refactor the
default grace period timer separately.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index e57360a8fd16..cb316053d3db 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1200,6 +1200,30 @@ 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
+ * ================
+ *
+ * Traditional 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.
+ * Note that an expiration value of zero means that the quota limit has not
+ * been reached, and therefore no expiration has been set.  Therefore, the
+ * ondisk min and max defined here can be used directly to constrain the incore
+ * quota expiration timestamps on a Unix system.
+ */
+
+/*
+ * Smallest possible ondisk quota expiration value with traditional timestamps.
+ * This corresponds exactly with the incore expiration Jan  1 00:00:01 UTC 1970.
+ */
+#define XFS_DQ_LEGACY_EXPIRY_MIN	((int64_t)1)
+
+/*
+ * Largest possible ondisk quota expiration value with traditional timestamps.
+ * This corresponds exactly with the incore expiration Feb  7 06:28:15 UTC 2106.
+ */
+#define XFS_DQ_LEGACY_EXPIRY_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
  * disk structure.