From d2430d50970deda19ac851669e685a1cc72a8200 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 6 Mar 2023 12:07:18 +0100
Subject: [PATCH] loop-util: add call for setting the autoclear flag at
 arbitrary times

---
 src/shared/loop-util.c | 19 +++++++++++++++++++
 src/shared/loop-util.h |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/src/shared/loop-util.c b/src/shared/loop-util.c
index 96a42b41257..27a58952bbd 100644
--- a/src/shared/loop-util.c
+++ b/src/shared/loop-util.c
@@ -1111,3 +1111,22 @@ int loop_device_sync(LoopDevice *d) {
 
         return RET_NERRNO(fsync(d->fd));
 }
+
+int loop_device_set_autoclear(LoopDevice *d, bool autoclear) {
+        struct loop_info64 info;
+
+        assert(d);
+
+        if (ioctl(d->fd, LOOP_GET_STATUS64, &info) < 0)
+                return -errno;
+
+        if (autoclear == FLAGS_SET(info.lo_flags, LO_FLAGS_AUTOCLEAR))
+                return 0;
+
+        SET_FLAG(info.lo_flags, LO_FLAGS_AUTOCLEAR, autoclear);
+
+        if (ioctl(d->fd, LOOP_SET_STATUS64, &info) < 0)
+                return -errno;
+
+        return 1;
+}
diff --git a/src/shared/loop-util.h b/src/shared/loop-util.h
index ea461434e9c..c98b69ceee7 100644
--- a/src/shared/loop-util.h
+++ b/src/shared/loop-util.h
@@ -49,3 +49,5 @@ int loop_device_refresh_size(LoopDevice *d, uint64_t offset, uint64_t size);
 
 int loop_device_flock(LoopDevice *d, int operation);
 int loop_device_sync(LoopDevice *d);
+
+int loop_device_set_autoclear(LoopDevice *d, bool autoclear);
-- 
2.47.3