[Ocfs2-tools-devel] [RESEND][PATCH] Improvement to tunefs.ocfs2 online resize to handle symbolic link

[Jiaju Zhang]

Hi Joel,

This is a simple patch which fixes the issue that tunefs.ocfs2 online
resize can't handle symbolic link file. My environemnt is ocfs2 with
user-space cluster stack and LVM being used. The user may often run
the command like 'tunefs.ocfs2 -S /dev/vg1/lv1' when online and then
fails.

After some debugging, I found for now the code doesn't know
'/dev/vg1/lv1' is a symbolic link to '/dev/mapper/vg1-lv1' but
actually they are the same device. So I use stat and get the st_rdev
to identify if those two are the same. I haven't used the method like
judging if one file is a symbolic link to another is because we also
need to handle the scenario that if one is not a symbolic link and
just two device names but they indicate the identical device, like
'/dev/mapper/vg1-lv1' and '/dev/dm-0'.

Thanks a lot for your time, review and comments;-)

Thanks,
Jiaju
---
 ocfs2_controld/mount.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/ocfs2_controld/mount.c b/ocfs2_controld/mount.c
index 36459d1..076f727 100644
--- a/ocfs2_controld/mount.c
+++ b/ocfs2_controld/mount.c
@@ -260,11 +260,13 @@ static void add_service(struct mountgroup *mg, const char *device,
 			   const char *service, int ci, int fd)
 {
 	struct service *ms;
+	struct stat st1, st2;
 
 	log_debug("Adding service %s to device %s uuid %s",
 		  service, device, mg->mg_uuid);
 
-	if (strcmp(mg->mg_device, device)) {
+	if (!stat(mg->mg_device, &st1) && !stat(device, &st2)
+	    && st1.st_rdev != st2.st_rdev) {
 		fill_error(mg, EINVAL,
 			   "Trying to mount fs %s on device %s, but it is already mounted from device %s",
 			   mg->mg_uuid, device, mg->mg_device);