commit fd0c59fdae3e12b7e09b5b3911987611ed997f6b
author Akilesh Kailash <akailash@google.com> Wed Dec 23 18:43:49 2020 +0000
committer Randall Huang <huangrandall@google.com> Thu Feb 18 08:40:25 2021 +0000
tree 47e901e315e04f6a58947f12f5ccfebf30ed9363
parent e5be87b8fe8a76872459eca83b09faf45bb4d121

fsync after block device writes

When markBoolSuccessful is invoked, we update
the partition table. These writes should be
synced before merge operation is resumed post OTA.
If not, any crash before these writes are landed to
backing storage will lead to incorrect switching of
slots.

BUG: 175711601
BUG: 177652253
Test: Verify slot switching correctly after crash when merge in progress
Signed-off-by: Akilesh Kailash <akailash@google.com>
Change-Id: I2da9286490d5d063df0c9d4dc491e0fbf28f51bb

gpt-utils/gpt-utils.cpp

diff --git a/gpt-utils/gpt-utils.cpp b/gpt-utils/gpt-utils.cpp
index f1f2858..c83ecc8 100644
--- a/gpt-utils/gpt-utils.cpp
+++ b/gpt-utils/gpt-utils.cpp
@@ -157,11 +157,18 @@
     else
         r = read(fd, buf, len);
 
-    if (r < 0)
+    if (r < 0) {
         fprintf(stderr, "block dev %s failed: %s\n", rw ? "write" : "read",
                 strerror(errno));
-    else
-        r = 0;
+    } else {
+        if (rw) {
+            r = fsync(fd);
+            if (r < 0)
+                fprintf(stderr, "fsync failed: %s\n", strerror(errno));
+        } else {
+            r = 0;
+        }
+    }
 
     return r;
 }