From: Luca Boccassi <luca.boccassi@microsoft.com>
Date: Mon, 10 Aug 2020 10:22:30 +0000 (+0100)
Subject: dissect: yield for 2ms when a verity device cannot be opened before retrying
X-Git-Tag: v247-rc1~429^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ecab4c470cae07a65a10e9aa2aec3878a06f2904;p=thirdparty%2Fsystemd.git

dissect: yield for 2ms when a verity device cannot be opened before retrying

If we don't succeed on the first try it's because another process is
opening the same device. Do a microsleep for 2ms to increase the
chances it has completed the next time around the loop.
---

diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index 97f0e46e788..66b7ec52846 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -1475,6 +1475,9 @@ static int verity_partition(
                 }
                 if (r == 0)
                         break;
+
+                /* Device is being opened by another process, but it has not finished yet, yield for 2ms */
+                (void) usleep(2 * USEC_PER_MSEC);
         }
 
         /* An existing verity device was reported by libcryptsetup/libdevmapper, but we can't use it at this time.