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>

lxc to apply mount options for bind mounts
e76b8764 · Ciprian Dorin, Craciun · Daniel Lezcano · a7dff834 · e76b8764
Commit e76b8764 authored Jun 24, 2010 by Ciprian Dorin, Craciun Committed by Daniel Lezcano Jun 24, 2010
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conf.c src/lxc/conf.c +17 -1

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--- 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);