From: Patrick Farrell <pfarrell@whamcloud.com>
Date: Wed, 23 Aug 2023 22:46:53 +0000 (-0400)
Subject: LU-13814 clio: Improve cl_io_submit_sync comments
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=refs%2Fchanges%2F73%2F52073%2F12;p=fs%2Flustre-release.git

LU-13814 clio: Improve cl_io_submit_sync comments

Add notes on what cl_io_submit_sync is for.

Test-Parameters: forjanitoronly
Test-Parameters: fortestonly
Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I5e32f1a7e6893b63d82f14848a865f90d30fb079
---

diff --git a/lustre/obdclass/cl_io.c b/lustre/obdclass/cl_io.c
index 62f3f74..d1ddd56 100644
--- a/lustre/obdclass/cl_io.c
+++ b/lustre/obdclass/cl_io.c
@@ -670,6 +670,9 @@ EXPORT_SYMBOL(cl_io_submit_rw);
 /**
  * Submit a sync_io and wait for the IO to be finished, or error happens.
  * If \a timeout is zero, it means to wait for the IO unconditionally.
+ *
+ * This is used for synchronous submission of an async IO, so the waiting is
+ * done here in this function and the IO is done when this function returns.
  */
 int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io,
 		      enum cl_req_type iot, struct cl_2queue *queue,
@@ -682,6 +685,10 @@ int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io,
 
 	cl_page_list_for_each(pg, &queue->c2_qin) {
 		LASSERT(pg->cp_sync_io == NULL);
+		/* this is for sync submission of async IO, IO that was always
+		 * sync (like DIO) is handled differently
+		 */
+		LASSERT(pg->cp_type != CPT_TRANSIENT);
 		pg->cp_sync_io = anchor;
 	}