xfs: refactor unmount record writing

Separate out the unmount record writing from the rest of the
ticket and log state futzing necessary to make it work. This is
a no-op, just makes the code cleaner and places the unmount record
formatting and writing alongside the commit record formatting and
writing code.

We can also get rid of the ticket flag clearing before the
xlog_write() call because it no longer cares about the state of
XLOG_TIC_INITED.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_log.c

@@ -795,32 +795,44 @@ xlog_wait_on_iclog(
 }
 
 /*
- * Final log writes as part of unmount.
- *
- * Mark the filesystem clean as unmount happens.  Note that during relocation
- * this routine needs to be executed as part of source-bag while the
- * deallocation must not be done until source-end.
+ * Write out an unmount record using the ticket provided. We have to account for
+ * the data space used in the unmount ticket as this write is not done from a
+ * transaction context that has already done the accounting for us.
  */
-
-/* Actually write the unmount record to disk. */
-static void
-xfs_log_write_unmount_record(
-	struct xfs_mount	*mp)
+static int
+xlog_write_unmount_record(
+	struct xlog		*log,
+	struct xlog_ticket	*ticket,
+	xfs_lsn_t		*lsn,
+	uint			flags)
 {
-	/* the data section must be 32 bit size aligned */
-	struct xfs_unmount_log_format magic = {
+	struct xfs_unmount_log_format ulf = {
 		.magic = XLOG_UNMOUNT_TYPE,
 	};
 	struct xfs_log_iovec reg = {
-		.i_addr = &magic,
-		.i_len = sizeof(magic),
+		.i_addr = &ulf,
+		.i_len = sizeof(ulf),
 		.i_type = XLOG_REG_TYPE_UNMOUNT,
 	};
 	struct xfs_log_vec vec = {
 		.lv_niovecs = 1,
 		.lv_iovecp = &reg,
 	};
-	struct xlog		*log = mp->m_log;
+
+	/* account for space used by record data */
+	ticket->t_curr_res -= sizeof(ulf);
+	return xlog_write(log, &vec, ticket, lsn, NULL, flags, false);
+}
+
+/*
+ * Mark the filesystem clean by writing an unmount record to the head of the
+ * log.
+ */
+static void
+xlog_unmount_write(
+	struct xlog		*log)
+{
+	struct xfs_mount	*mp = log->l_mp;
 	struct xlog_in_core	*iclog;
 	struct xlog_ticket	*tic = NULL;
 	xfs_lsn_t		lsn;
@@ -844,10 +856,7 @@ xfs_log_write_unmount_record(
 		flags &= ~XLOG_UNMOUNT_TRANS;
 	}
 
-	/* remove inited flag, and account for space used */
-	tic->t_flags = 0;
-	tic->t_curr_res -= sizeof(magic);
-	error = xlog_write(log, &vec, tic, &lsn, NULL, flags, false);
+	error = xlog_write_unmount_record(log, tic, &lsn, flags);
 	/*
 	 * At this point, we're umounting anyway, so there's no point in
 	 * transitioning log state to IOERROR. Just continue...
@@ -913,7 +922,7 @@ xfs_log_unmount_write(
 	if (XLOG_FORCED_SHUTDOWN(log))
 		return;
 	xfs_log_unmount_verify_iclog(log);
-	xfs_log_write_unmount_record(mp);
+	xlog_unmount_write(log);
 }
 
 /*