From: Ciprian Dorin, Craciun <ciprian@volution.ro>
Date: Thu, 24 Jun 2010 07:47:14 +0000 (+0200)
Subject: lxc to apply mount options for bind mounts
X-Git-Tag: lxc-0.7.1~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e76b8764fa0aa1873724a9e4a8a3ca93c0e5cd70;p=thirdparty%2Flxc.git

lxc to apply mount options for bind mounts

Hello all!

    This bug stalked me for a while, but only now it bit me quite
badly... (Lost about an hour of work...)

    So the culprit: inside the fstab file for the `lxc.mount` option I
can use options like `ro` together with `bind`. Unfortunately the
kernel just laughs in my face and ignores any options I've put in
there... :) But not any more: I've updated `./src/lxc/conf.c`
(`mount_file_entries` function) so that when it encounters a `bind`
option it executes it twice (one without any extra options, and a
second time with the remount flag set.)

I've marginally (as in my particular case) tested it and it works.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
---

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 66c60a8d7..3aaf31cbc 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -799,12 +799,28 @@ static int mount_file_entries(FILE *file)
 		}
 
 		if (mount(mntent->mnt_fsname, mntent->mnt_dir,
-			  mntent->mnt_type, mntflags, mntdata)) {
+			  mntent->mnt_type, mntflags & ~MS_REMOUNT, mntdata)) {
 			SYSERROR("failed to mount '%s' on '%s'",
 					 mntent->mnt_fsname, mntent->mnt_dir);
 			goto out;
 		}
 
+		if ((mntflags & MS_REMOUNT) == MS_REMOUNT ||
+		    ((mntflags & MS_BIND) == MS_BIND)) {
+
+			DEBUG ("remounting %s on %s to respect bind " \
+			       "or remount options",
+			       mntent->mnt_fsname, mntent->mnt_dir);
+
+			if (mount(mntent->mnt_fsname, mntent->mnt_dir,
+				  mntent->mnt_type,
+				  mntflags | MS_REMOUNT, mntdata)) {
+				SYSERROR("failed to mount '%s' on '%s'",
+					 mntent->mnt_fsname, mntent->mnt_dir);
+				goto out;
+			}
+		}
+
 		DEBUG("mounted %s on %s, type %s", mntent->mnt_fsname,
 		      mntent->mnt_dir, mntent->mnt_type);