File util-linux-loop-reuse-09.patch of Package util-linux.4136

From bfd4e1f75898510f93779766688cc5086404c23b Mon Sep 17 00:00:00 2001
From: Stanislav Brabec <sbrabec@suse.cz>
Date: Tue, 2 Aug 2016 19:57:56 +0200
Subject: [PATCH 9/20] loopdev: Implememt loopcxt_set_status()

Implement stand-alone loopcxt_set_status(). It allows manipulation with some
loop device parameters even if it is initialized.

Its function is limited by the kernel implementation, and only a small subset of
changes is allowed.

For more see linux/drivers/block/loop.c:loop_set_status()

Signed-off-by: Stanislav Brabec <sbrabec@suse.cz>
---
 include/loopdev.h |  1 +
 lib/loopdev.c     | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

Index: util-linux-2.25/include/loopdev.h
===================================================================
--- util-linux-2.25.orig/include/loopdev.h
+++ util-linux-2.25/include/loopdev.h
@@ -164,6 +164,7 @@ extern int loopcxt_deinit_iterator(struc
 extern int loopcxt_next(struct loopdev_cxt *lc);
 
 extern int loopcxt_setup_device(struct loopdev_cxt *lc);
+extern int loopcxt_set_status(struct loopdev_cxt *lc);
 extern int loopcxt_delete_device(struct loopdev_cxt *lc);
 extern int loopcxt_set_capacity(struct loopdev_cxt *lc);
 
Index: util-linux-2.25/lib/loopdev.c
===================================================================
--- util-linux-2.25.orig/lib/loopdev.c
+++ util-linux-2.25/lib/loopdev.c
@@ -1196,7 +1196,7 @@ static int loopcxt_check_size(struct loo
 }
 
 /*
- * @cl: context
+ * @lc: context
  *
  * Associate the current device (see loopcxt_{set,get}_device()) with
  * a file (see loopcxt_set_backing_file()).
@@ -1314,6 +1314,40 @@ err:
 	return rc;
 }
 
+/*
+ * @lc: context
+ *
+ * Update status of the current device (see loopcxt_{set,get}_device()).
+ *
+ * Note that once initialized, kernel accepts only selected changes:
+ * LO_FLAGS_AUTOCLEAR and LO_FLAGS_PARTSCAN
+ * For more see linux/drivers/block/loop.c:loop_set_status()
+ *
+ * Returns: <0 on error, 0 on success.
+ */
+int loopcxt_set_status(struct loopdev_cxt *lc)
+{
+	int dev_fd, rc = -1;
+
+	errno = 0;
+	dev_fd = loopcxt_get_fd(lc);
+
+	if (dev_fd < 0) {
+		rc = -errno;
+		return rc;
+	}
+	DBG(lc, loopdev_debug("device open: OK"));
+
+	if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) {
+		rc = -errno;
+		DBG(lc, loopdev_debug("LOOP_SET_STATUS64 failed: %m"));
+		return rc;
+	}
+
+	DBG(lc, loopdev_debug("LOOP_SET_STATUS64: OK"));
+	return 0;
+}
+
 int loopcxt_set_capacity(struct loopdev_cxt *lc)
 {
 	int fd = loopcxt_get_fd(lc);