[LTP] [PATCH 2/2] c-test-api: Documentation updated

[Alessandro Carminati]

Since the tst_find_backing_dev logic is changed, the doc is updated
accordingly.

Signed-off-by: Alessandro Carminati <alessandro.carminati@gmail.com>
---
 doc/c-test-api.txt | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/doc/c-test-api.txt b/doc/c-test-api.txt
index 64ee3397f..a7888c242 100644
--- a/doc/c-test-api.txt
+++ b/doc/c-test-api.txt
@@ -1071,8 +1071,11 @@ voud tst_find_backing_dev(const char *path, char *dev);
 -------------------------------------------------------------------------------
 
 This function finds the block dev that this path belongs to, it uses stat function
-to get the major/minor number of the path. Then scan them in '/proc/self/mountinfo'
-and list 2th column value after ' - ' string as its block dev if match succeeds.
+to get the major/minor number of the path. 
+This function finds the block dev that this path belongs to, it uses the unevent 
+file in sysfs to find the device name. It needs to discriminate between btrfs
+and not btrfs. For non btrfs filesystems it uses the minor, major numbers. For
+btrfs it uses the fs uuid.
 
 [source,c]
 -------------------------------------------------------------------------------
-- 
2.34.1