On Tue, Jul 31, 2012 at 04:58:42PM +1000, NeilBrown wrote:
>
> 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;
> }
The same code you can found in original non-libmount version
in nfsumount.c *but* with correct nfs_umount_is_vers4() return codes.
>
> 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.
You're right, should be (copy & past from nfsumount.c):
* Returns 1 if "mc" is an NFSv4 mount, zero if not, and
* -1 if some error occurred.
...probably my bug. Sorry.
> 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??
The is_vers4() should be fixed to be compatible with the original code.
> 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.
Yes.
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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