in nfs-utils, in utils/mount/mount_libmount.c there is a function
is_vers4()
which
/* returns: error = -1, success = 0 , unknown = 1 */
which seems odd to me... I would have chosen '1' for success (it is vers 4),
0 for failure (not vers 4), and maybe -1 for error (something went wrong).
This is used as follows:
switch (is_vers4(cxt)) {
case 0:
/* We ignore the error from nfs_umount23.
* If the actual umount succeeds (in del_mtab),
* we don't want to signal an error, as that
* could cause /sbin/mount to retry!
*/
nfs_umount23(mnt_context_get_source(cxt), opts);
break;
case 1: /* unknown */
break;
default: /* error */
goto err;
}
so in the '0' (success, it is vers4) case we do nfs_umount23. Odd.
In the '1' (unknown, so presumably vers2 or 3) we don't. Ever. Very odd.
So we don't currently send MOUNT_UMNT requests for v2 or v3.
We don't for v4 either because nfs_umount_do_umnt contains:
/* Skip UMNT call for vers=4 mounts */
if (nfs_pmap.pm_vers == 4)
return EX_SUCCESS;
so maybe is_vers4 isn't needed?
Looks like something needs to be fixed here but I'm not entirely sure what.
Karel??
BTW Steve, Karel's "[PATCH] umount.nfs: ignore non-nfs filesystems"
which appears in email:
From: Karel Zak <kzak@xxxxxxxxxx>
To: NeilBrown <neilb@xxxxxxx>
Cc: Steve Dickson <SteveD@xxxxxxxxxx>, NFS <linux-nfs@xxxxxxxxxxxxxxx>
Subject: Re: [PATCH] umount.nfs: restore correct error status when umount fails.
Date: Thu, 12 Jul 2012 18:44:20 +0200
hasn't been applied, but probably should be.
Thanks,
NeilBrown
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