[XFS] Fixes the leak in reservation space because we weren't ungranting

space for the unmount record - which becomes a problem in the freeze/thaw
scenario.

SGI-PV: 942533
SGI-Modid: xfs-linux-melb:xfs-kern:26815a

Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/xfs_log.c

@@ -617,7 +617,8 @@ xfs_log_unmount_write(xfs_mount_t *mp)
 		reg[0].i_len  = sizeof(magic);
 		XLOG_VEC_SET_TYPE(&reg[0], XLOG_REG_TYPE_UNMOUNT);
 
-		error = xfs_log_reserve(mp, 600, 1, &tic, XFS_LOG, 0, 0);
+		error = xfs_log_reserve(mp, 600, 1, &tic,
+					XFS_LOG, 0, XLOG_UNMOUNT_REC_TYPE);
 		if (!error) {
 			/* remove inited flag */
 			((xlog_ticket_t *)tic)->t_flags = 0;
@@ -655,8 +656,11 @@ xfs_log_unmount_write(xfs_mount_t *mp)
 		} else {
 			LOG_UNLOCK(log, s);
 		}
-		if (tic)
+		if (tic) {
+			xlog_trace_loggrant(log, tic, "unmount rec");
+			xlog_ungrant_log_space(log, tic);
 			xlog_state_put_ticket(log, tic);
+		}
 	} else {
 		/*
 		 * We're already in forced_shutdown mode, couldn't

fs/xfs/xfs_log_priv.h

@@ -502,6 +502,12 @@ extern int	 xlog_bread(xlog_t *, xfs_daddr_t, int, struct xfs_buf *);
 #define XLOG_TRACE_SLEEP_FLUSH 3
 #define XLOG_TRACE_WAKE_FLUSH  4
 
+/*
+ * Unmount record type is used as a pseudo transaction type for the ticket.
+ * It's value must be outside the range of XFS_TRANS_* values.
+ */
+#define XLOG_UNMOUNT_REC_TYPE	(-1U)
+
 #endif	/* __KERNEL__ */
 
 #endif	/* __XFS_LOG_PRIV_H__ */