dovecot - Jul 2009 - Unable to (un)subscribe mbox with AIX, NFS and netapp filer

Hi Timo,

dovecot 1.2.0 is great! Faster and more stable on mboxes that 1.1.x by
far... good job :-)

Today I stumbled over a strange problem when I tried to subscribe an
existing Mailbox (mbox), which doesn't work.

Thunderbird IMAP log
--------------------
9932[4124558]: 40f3498:imap.fh-trier.de:A:SendData:
                11 subscribe "Mail/Archiv/1998"
9932[4124558]: ReadNextLine [stream=403f280 nb=108 needmore=0]
9932[4124558]: 40f3498:imap.fh-trier.de:A:CreateNewLineFromSocket:
                11 NO [SERVERBUG] Internal error occurred.
                Refer to server log for more information.
                [2009-07-06 08:14:32]

Server log
----------
Jul  6 08:14:32 trevi mail:info dovecot: IMAP(beckerr):
  Namespace Mail/: Using permissions from
  /u/f0/rzuser/beckerr/Mail: mode=0700 gid=-1

Jul  6 08:14:32 trevi mail:err|error dovecot: IMAP(beckerr):
  fchown(/u/f0/rzuser/beckerr/Mail/.subscriptions.lock, -1, -1)
  failed: Invalid argument

Jul  6 08:14:32 trevi mail:err|error dovecot: IMAP(beckerr):
  file_dotlock_open() failed with subscription file
  /u/f0/rzuser/beckerr/Mail/.subscriptions: Invalid argument




The error just appears on NFS mounted shared and I'm not sure if
AIX or netapp is the cause. So to determine the real problem is
not easy, but to fix it is:

While uid and gid are both -1 the call could be suppressed, because
nothing is really changed:

--- ./lib/file-dotlock.c.org	2009-07-06 09:25:14.000000000 +0200
+++ ./lib/file-dotlock.c	2009-07-06 09:24:48.000000000 +0200
@@ -780,7 +780,7 @@
 	fd = file_dotlock_open(set, path, flags, &dotlock);
 	umask(old_mask);

-	if (fd != -1) {
+	if (fd != -1 && (uid != -1 || gid != -1)) {
 		if (fchown(fd, uid, gid) < 0) {
 			if (errno == EPERM && uid == (uid_t)-1) {
 				i_error("%s", eperm_error_get_chgrp("fchown",




Ralf
-- 
______________________________________________________________________

 Dipl.-Inform. (FH) Ralf Becker     Rechenzentrum (r/ft) der FH Trier
 (Network|Mail|Web|Firewall)           University of applied sciences
 Administrator                           Schneidershof, D-54293 Trier

   Mail: beckerr at fh-trier.de                    Fon: +49 651 8103 499
    Web: http://www.fh-trier.de/~beckerr        Fax: +49 651 8103 214
 PubKey: http://www.fh-trier.de/~beckerr     Crypto: GnuPG, S/MIME
______________________________________________________________________

 Wenn Gott gewollt haette, dass E-Mail in HTML geschrieben wuerden,
 endeten Gebete traditionell mit </amen>. (Tom Listen)
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Le 6 juil. 09 ? 09:47, Ralf Becker a ?crit :
> [...]
>
> Jul  6 08:14:32 trevi mail:err|error dovecot: IMAP(beckerr):
>  fchown(/u/f0/rzuser/beckerr/Mail/.subscriptions.lock, -1, -1)
>  failed: Invalid argument
>
> [...]
>
> The error just appears on NFS mounted shared and I'm not sure if
> AIX or netapp is the cause.
According to the posix specification, fchown may return EINVAL when  
the owner or group ID is not a value supported by the implementation,  
or when the fildes argument refers to a pipe or socket or an fattach()- 
ed STREAM and the implementation disallows execution of fchown() on a  
pipe.

Wouldn't it be worth to check what kind of entity gets created under  
your environment?
I ask because I wouldn't exclude without further investigations the  
possibility of encountering other side effects wrt files throughout  
the code.

> So to determine the real problem is
> not easy, but to fix it is:
>
> While uid and gid are both -1 the call could be suppressed, because
> nothing is really changed:
>
> --- ./lib/file-dotlock.c.org	2009-07-06 09:25:14.000000000 +0200
> +++ ./lib/file-dotlock.c	2009-07-06 09:24:48.000000000 +0200
> @@ -780,7 +780,7 @@
> 	fd = file_dotlock_open(set, path, flags, &dotlock);
> 	umask(old_mask);
>
> -	if (fd != -1) {
> +	if (fd != -1 && (uid != -1 || gid != -1)) {
> 		if (fchown(fd, uid, gid) < 0) {
> 			if (errno == EPERM && uid == (uid_t)-1) {
> 				i_error("%s", eperm_error_get_chgrp("fchown",
Alternatively, perhaps could you write a small c program so as to test  
a fchown(fd,-1,-1) operation on a "regular" file as see whether it  
fails or not.

HTH,
Axel