[PATCH v3 1/3] xfsprogs: sync xfs_calc_buf_res() to user space

Jeff Liu
2013-02-19T05:31:34Z

Sync the new helper xfs_calc_buf_res() to user space.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>

---
libxfs/xfs_trans.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/libxfs/xfs_trans.c b/libxfs/xfs_trans.c
index 635de8f..d7ff1a9 100644
--- a/libxfs/xfs_trans.c
+++ b/libxfs/xfs_trans.c
@@ -23,6 +23,35 @@ kmem_zone_t *xfs_trans_zone;
kmem_zone_t *xfs_log_item_desc_zone;

/*
+ * A buffer has a format structure overhead in the log in addition
+ * to the data, so we need to take this into account when reserving
+ * space in a transaction for a buffer. Round the space required up
+ * to a multiple of 128 bytes so that we don't change the historical
+ * reservation that has been used for this overhead.
+ */
+STATIC uint
+xfs_buf_log_overhead(void)
+{
+ return round_up(sizeof(struct xlog_op_header) +
+ sizeof(struct xfs_buf_log_format), 128);
+}
+
+/*
+ * Calculate out transaction log reservation per item in bytes.
+ *
+ * The nbufs argument is used to indicate the number of items that
+ * will be changed in a transaction. size is used to tell how many
+ * bytes should be reserved per item.
+ */
+STATIC uint
+xfs_calc_buf_res(
+ uint nbufs,
+ uint size)
+{
+ return nbufs * (size + xfs_buf_log_overhead());
+}
+
+/*
* Various log reservation values.
*
* These are based on the size of the file system block because that is what
--
1.7.9.5