[LTP] [PATCH] lib/tst_device.c: Make sure all loop deivces fot test are detached

[Xiao Yang]

Running statx05 by runltp without -b option every time attached a loop
device but didn't detach it, as below:
------------------------------------------------------------------
...
tst_device.c:230: INFO: Using test device LTP_DEV='/dev/loop0'
tst_device.c:268: INFO: Skipping $LTP_DEV size 256MB, requested size 512MB
tst_device.c:83: INFO: Found free device '/dev/loop1'
tst_mkfs.c:83: INFO: Formatting /dev/loop1 with ext4 opts='' extra opts='-O encrypt'
...
NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE                                         DIO
/dev/loop1         0      0         0  0 /tmp/ltp-gsrcFAkGpZ/Wka3bp/test_dev.img (deleted)   0
------------------------------------------------------------------

runltp created a block device with default 256M size by attaching a free loop
device and set LTP_DEV variable, but statx05 needed a 512M block device, so
tst_acquire_device__() in setup skipped the $LTP_DEV device and created another
block device with 512M size by attaching another free loop device.  Unfortunately,
tst_release_device() in cleanup cannot detach the 512M block device due to the
defined LTP_DEV.

We should just skip the detach in tst_release_device() when LTP_DEV variable is
set and device_acquired flag is not set.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
---
 lib/tst_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/tst_device.c b/lib/tst_device.c
index 463743443..23c99dba2 100644
--- a/lib/tst_device.c
+++ b/lib/tst_device.c
@@ -313,7 +313,7 @@ int tst_release_device(const char *dev)
 {
 	int ret;
 
-	if (getenv("LTP_DEV"))
+	if (getenv("LTP_DEV") && !device_acquired)
 		return 0;
 
 	/*
-- 
2.17.0