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@xxxxxxx>
---
include/loopdev.h | 1 +
lib/loopdev.c | 36 +++++++++++++++++++++++++++++++++++-
2 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/include/loopdev.h b/include/loopdev.h
index 706388e..c331b59 100644
--- a/include/loopdev.h
+++ b/include/loopdev.h
@@ -164,6 +164,7 @@ extern int loopcxt_deinit_iterator(struct loopdev_cxt *lc);
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);
extern int loopcxt_set_dio(struct loopdev_cxt *lc, unsigned long use_dio);
diff --git a/lib/loopdev.c b/lib/loopdev.c
index 4606003..b20a9c2 100644
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -1206,7 +1206,7 @@ static int loopcxt_check_size(struct loopdev_cxt *lc, int file_fd)
}
/*
- * @cl: context
+ * @lc: context
*
* Associate the current device (see loopcxt_{set,get}_device()) with
* a file (see loopcxt_set_backing_file()).
@@ -1330,6 +1330,40 @@ 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(SETUP, ul_debugobj(lc, "device open: OK"));
+
+ if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) {
+ rc = -errno;
+ DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64 failed: %m"));
+ return rc;
+ }
+
+ DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64: OK"));
+ return 0;
+}
+
int loopcxt_set_capacity(struct loopdev_cxt *lc)
{
int fd = loopcxt_get_fd(lc);
--
2.9.2
--
Best Regards / S pozdravem,
Stanislav Brabec
software developer
---------------------------------------------------------------------
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