From: Dave Chinner <dchinner@xxxxxxxxxx>
Introduce an optimised version of xlog_write() that is used when the
entire write will fit in a single iclog. This greatly simplifies the
implementation of writing a log vector chain into an iclog, and sets
the ground work for a much more understandable xlog_write()
implementation.
This incorporates some factoring and simplifications proposed by
Christoph Hellwig.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/xfs/xfs_log.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 68 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index f26c85dbc765..44134f8e699c 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -2224,6 +2224,60 @@ xlog_print_trans(
}
}
+static inline void
+xlog_write_iovec(
+ struct xlog_in_core *iclog,
+ uint32_t *log_offset,
+ void *data,
+ uint32_t write_len,
+ int *bytes_left,
+ uint32_t *record_cnt,
+ uint32_t *data_cnt)
+{
+ ASSERT(*log_offset % sizeof(int32_t) == 0);
+ ASSERT(write_len % sizeof(int32_t) == 0);
+
+ memcpy(iclog->ic_datap + *log_offset, data, write_len);
+ *log_offset += write_len;
+ *bytes_left -= write_len;
+ (*record_cnt)++;
+ *data_cnt += write_len;
+}
+
+/*
+ * Write log vectors into a single iclog which is guaranteed by the caller
+ * to have enough space to write the entire log vector into.
+ */
+static void
+xlog_write_full(
+ struct xfs_log_vec *lv,
+ struct xlog_ticket *ticket,
+ struct xlog_in_core *iclog,
+ uint32_t *log_offset,
+ uint32_t *len,
+ uint32_t *record_cnt,
+ uint32_t *data_cnt)
+{
+ int index;
+
+ ASSERT(*log_offset + *len <= iclog->ic_size);
+
+ /*
+ * Ordered log vectors have no regions to write so this
+ * loop will naturally skip them.
+ */
+ for (index = 0; index < lv->lv_niovecs; index++) {
+ struct xfs_log_iovec *reg = &lv->lv_iovecp[index];
+ struct xlog_op_header *ophdr = reg->i_addr;
+
+ ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
+ ophdr->oh_len = cpu_to_be32(reg->i_len -
+ sizeof(struct xlog_op_header));
+ xlog_write_iovec(iclog, log_offset, reg->i_addr,
+ reg->i_len, len, record_cnt, data_cnt);
+ }
+}
+
static xlog_op_header_t *
xlog_write_setup_ophdr(
struct xlog_op_header *ophdr,
@@ -2388,8 +2442,8 @@ xlog_write(
int partial_copy = 0;
int partial_copy_len = 0;
int contwr = 0;
- int record_cnt = 0;
- int data_cnt = 0;
+ uint32_t record_cnt = 0;
+ uint32_t data_cnt = 0;
int error = 0;
if (ticket->t_curr_res < 0) {
@@ -2409,7 +2463,6 @@ xlog_write(
return error;
ASSERT(log_offset <= iclog->ic_size - 1);
- ptr = iclog->ic_datap + log_offset;
/*
* If we have a context pointer, pass it the first iclog we are
@@ -2421,10 +2474,22 @@ xlog_write(
ctx = NULL;
}
+ /* If this is a single iclog write, go fast... */
+ if (!contwr && lv == log_vector) {
+ while (lv) {
+ xlog_write_full(lv, ticket, iclog, &log_offset,
+ &len, &record_cnt, &data_cnt);
+ lv = lv->lv_next;
+ }
+ data_cnt = 0;
+ break;
+ }
+
/*
* This loop writes out as many regions as can fit in the amount
* of space which was allocated by xlog_state_get_iclog_space().
*/
+ ptr = iclog->ic_datap + log_offset;
while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
struct xfs_log_iovec *reg;
struct xlog_op_header *ophdr;
--
2.33.0
