[PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Steve Dickson]

During some recent testing, mounts were mysteriously failing to some 
servers but not to others. The mounts that were failure were in a very sparse 
environment. Meaning very little in any supporting utilities, like
/bin/cat, /bin/ls or system-wide configuration files.

The reason the mounts were failing was /etc/netconfig did not exist. 
Even in the cases when all the information that would have been pulled
from /etc/netconfig already existed or was easily attainable 

So the patch tries to recover from when system files are inaccessible 
and the need information already exists or is well known. 
 
steved.

Author: Steve Dickson <steved@redhat.com>
Date:   Wed Jan 27 11:19:00 2010 -0500
    
    In a very sparse environments certain system files (like
    /etc/netconfig) may not exist. In these environments don't
    fail mount if all the need information (like network protocols)
    exist and are well known.
    
    Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/support/nfs/getport.c b/support/nfs/getport.c
index c930539..e490dd4 100644
--- a/support/nfs/getport.c
+++ b/support/nfs/getport.c
@@ -277,7 +277,7 @@ nfs_get_proto(const char *netid, sa_family_t *family, unsigned long *protocol)
 #ifdef HAVE_LIBTIRPC
 char *nfs_get_netid(const sa_family_t family, const unsigned long protocol)
 {
-	char *nc_protofmly, *nc_proto, *nc_netid;
+	char *nc_protofmly, *nc_proto, *nc_netid = NULL;
 	struct netconfig *nconf;
 	struct protoent *proto;
 	void *handle;
@@ -319,6 +319,19 @@ char *nfs_get_netid(const sa_family_t family, const unsigned long protocol)
 	endnetconfig(handle);
 
 out:
+	/*
+	 * The system configuration files are inaccessible 
+	 * so see if these are well known protocols
+	 */
+	if (protocol == IPPROTO_TCP)
+		nc_netid = (family == AF_INET6 ? 
+			strdup("tcp6") : strdup("tcp"));
+	else if (protocol == IPPROTO_UDP)
+		nc_netid = (family == AF_INET6 ? 
+			strdup("udp6") : strdup("udp"));
+	if (nc_netid != NULL)
+		return nc_netid;
+
 	rpc_createerr.cf_stat = RPC_UNKNOWNPROTO;
 	return NULL;
 }
diff --git a/utils/mount/network.c b/utils/mount/network.c
index 06cab6a..fa99bc1 100644
--- a/utils/mount/network.c
+++ b/utils/mount/network.c
@@ -1270,7 +1270,26 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
 	*version = 0;
 	return 1;
 }
-
+/*
+ * Returns TRUE if the option string is a well known protocol
+ */
+int 
+nfs_set_proto(char *option,  unsigned long *protocol)
+{
+	if (strcmp(option, "tcp") == 0 || 
+			strcmp(option, "tcp6") == 0) {
+		*protocol = IPPROTO_TCP;
+		return 1;
+	}
+	if (strcmp(option, "udp") == 0 ||
+			strcmp(option, "udp6") == 0) {
+		*protocol = IPPROTO_UDP;
+		return 1;
+	}
+	if (verbose)
+		nfs_error(_("%s: unkown protocol: '%s'"), progname, option);
+	return 0;
+}
 /*
  * Returns TRUE if @protocol contains a valid value for this option,
  * or FALSE if the option was specified with an invalid value.
@@ -1290,8 +1309,13 @@ nfs_nfs_protocol(struct mount_options *options, unsigned long *protocol)
 		return 1;
 	case 2: /* proto */
 		option = po_get(options, "proto");
-		if (option != NULL)
-			return nfs_get_proto(option, &family, protocol);
+		if (option != NULL) {
+			if (nfs_get_proto(option, &family, protocol))
+				return 1;
+			if (nfs_set_proto(option, protocol))
+				return 1;
+			return 0;
+		}
 	}
 
 	/*
@@ -1438,8 +1462,13 @@ nfs_mount_protocol(struct mount_options *options, unsigned long *protocol)
 	char *option;
 
 	option = po_get(options, "mountproto");
-	if (option != NULL)
-		return nfs_get_proto(option, &family, protocol);
+	if (option != NULL) {
+		if (nfs_get_proto(option, &family, protocol))
+			return 1;
+		if (nfs_set_proto(option, protocol))
+			return 1;
+		return 0;
+	}
 
 	/*
 	 * MNT transport protocol wasn't specified.  If the NFS

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Chuck Lever]

On 01/27/2010 11:41 AM, Steve Dickson wrote:
> During some recent testing, mounts were mysteriously failing to some
> servers but not to others. The mounts that were failure were in a very sparse
> environment. Meaning very little in any supporting utilities, like
> /bin/cat, /bin/ls or system-wide configuration files.
>
> The reason the mounts were failing was /etc/netconfig did not exist.
> Even in the cases when all the information that would have been pulled
> from /etc/netconfig already existed or was easily attainable
>
> So the patch tries to recover from when system files are inaccessible
> and the need information already exists or is well known.
>
> steved.
>
> Author: Steve Dickson<steved@redhat.com>
> Date:   Wed Jan 27 11:19:00 2010 -0500
>
>      In a very sparse environments certain system files (like
>      /etc/netconfig) may not exist. In these environments don't
>      fail mount if all the need information (like network protocols)
>      exist and are well known.
>
>      Signed-off-by: Steve Dickson<steved@redhat.com>

I totally disagree with this.  If HAVE_LIBTIRPC is set, then the runtime 
TI-RPC package should be installed, in its entirety, on the run-time 
systems.  If autoconf and RPM can't trust the given dependency 
information, then all bets are off.

The right fix is to either:

a) install a non-TI-RPC version of mount.nfs, or

b) make sure /etc/netconfig is available when RPM, pkgconfig, and 
autoconf say it should be.

Mount.nfs is not the only program that needs to have this information.

I assume since you are not patching other parts of mount.nfs that look 
for /etc/rpc and /etc/protocols that these files _do_ exist?  Or does 
glibc also do this hack of filling in well-known values?

> diff --git a/support/nfs/getport.c b/support/nfs/getport.c
> index c930539..e490dd4 100644
> --- a/support/nfs/getport.c
> +++ b/support/nfs/getport.c
> @@ -277,7 +277,7 @@ nfs_get_proto(const char *netid, sa_family_t *family, unsigned long *protocol)
>   #ifdef HAVE_LIBTIRPC
>   char *nfs_get_netid(const sa_family_t family, const unsigned long protocol)
>   {
> -	char *nc_protofmly, *nc_proto, *nc_netid;
> +	char *nc_protofmly, *nc_proto, *nc_netid = NULL;
>   	struct netconfig *nconf;
>   	struct protoent *proto;
>   	void *handle;
> @@ -319,6 +319,19 @@ char *nfs_get_netid(const sa_family_t family, const unsigned long protocol)
>   	endnetconfig(handle);
>
>   out:
> +	/*
> +	 * The system configuration files are inaccessible
> +	 * so see if these are well known protocols
> +	 */
> +	if (protocol == IPPROTO_TCP)
> +		nc_netid = (family == AF_INET6 ?
> +			strdup("tcp6") : strdup("tcp"));
> +	else if (protocol == IPPROTO_UDP)
> +		nc_netid = (family == AF_INET6 ?
> +			strdup("udp6") : strdup("udp"));
> +	if (nc_netid != NULL)
> +		return nc_netid;
> +
>   	rpc_createerr.cf_stat = RPC_UNKNOWNPROTO;
>   	return NULL;
>   }
> diff --git a/utils/mount/network.c b/utils/mount/network.c
> index 06cab6a..fa99bc1 100644
> --- a/utils/mount/network.c
> +++ b/utils/mount/network.c
> @@ -1270,7 +1270,26 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
>   	*version = 0;
>   	return 1;
>   }
> -
> +/*
> + * Returns TRUE if the option string is a well known protocol
> + */
> +int
> +nfs_set_proto(char *option,  unsigned long *protocol)
> +{
> +	if (strcmp(option, "tcp") == 0 ||
> +			strcmp(option, "tcp6") == 0) {
> +		*protocol = IPPROTO_TCP;
> +		return 1;
> +	}
> +	if (strcmp(option, "udp") == 0 ||
> +			strcmp(option, "udp6") == 0) {
> +		*protocol = IPPROTO_UDP;
> +		return 1;
> +	}
> +	if (verbose)
> +		nfs_error(_("%s: unkown protocol: '%s'"), progname, option);
> +	return 0;
> +}
>   /*
>    * Returns TRUE if @protocol contains a valid value for this option,
>    * or FALSE if the option was specified with an invalid value.
> @@ -1290,8 +1309,13 @@ nfs_nfs_protocol(struct mount_options *options, unsigned long *protocol)
>   		return 1;
>   	case 2: /* proto */
>   		option = po_get(options, "proto");
> -		if (option != NULL)
> -			return nfs_get_proto(option,&family, protocol);
> +		if (option != NULL) {
> +			if (nfs_get_proto(option,&family, protocol))
> +				return 1;
> +			if (nfs_set_proto(option, protocol))
> +				return 1;
> +			return 0;
> +		}
>   	}
>
>   	/*
> @@ -1438,8 +1462,13 @@ nfs_mount_protocol(struct mount_options *options, unsigned long *protocol)
>   	char *option;
>
>   	option = po_get(options, "mountproto");
> -	if (option != NULL)
> -		return nfs_get_proto(option,&family, protocol);
> +	if (option != NULL) {
> +		if (nfs_get_proto(option,&family, protocol))
> +			return 1;
> +		if (nfs_set_proto(option, protocol))
> +			return 1;
> +		return 0;
> +	}
>
>   	/*
>   	 * MNT transport protocol wasn't specified.  If the NFS

-- 
chuck[dot]lever[at]oracle[dot]com

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Steve Dickson]

On 01/27/2010 01:09 PM, Chuck Lever wrote:
>> Author: Steve Dickson<steved@redhat.com>
>> Date:   Wed Jan 27 11:19:00 2010 -0500
>>
>>      In a very sparse environments certain system files (like
>>      /etc/netconfig) may not exist. In these environments don't
>>      fail mount if all the need information (like network protocols)
>>      exist and are well known.
>>
>>      Signed-off-by: Steve Dickson<steved@redhat.com>
> 
> I totally disagree with this.  If HAVE_LIBTIRPC is set, then the runtime
> TI-RPC package should be installed, in its entirety, on the run-time
> systems.  If autoconf and RPM can't trust the given dependency
> information, then all bets are off.
Well in some environments "all bets are off" is just not good enough...
Mount has always worked in these type of  environments before and 
I think we should continue to... 

> 
> The right fix is to either:
> 
> a) install a non-TI-RPC version of mount.nfs, or
> 
> b) make sure /etc/netconfig is available when RPM, pkgconfig, and
> autoconf say it should be.
> 
Sparse environments generally have a finite amount of space, that
is simple unchangeable... so the above "luxuries" are simply not 
available...

> 
> I assume since you are not patching other parts of mount.nfs that look
> for /etc/rpc and /etc/protocols that these files _do_ exist?  Or does
> glibc also do this hack of filling in well-known values?
> 
Lets keep this in perspective... the "well-known" values in this patch
things like TCP and UDP... when protocol == IPPROTO_TCP the well known value
is "tcp" (or "tcp6" depending on the family)... Values that have not 
changed for years and will not change for years... 

On the umount side, the file should not be consulted in the first place
since all the information needed in /etc/mtab... Of course things
can change between mount and umounts but I truly do no think the
meaning of "udp" will change from being IPPROTO_UDP....

Making mount more bullet proof and allowing it (continue to) work in all 
different types of environments is a good thing... imho...

steved.

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Chuck Lever]

On Jan 27, 2010, at 1:42 PM, Steve Dickson wrote:
> On 01/27/2010 01:09 PM, Chuck Lever wrote:
>>> Author: Steve Dickson<steved@redhat.com>
>>> Date:   Wed Jan 27 11:19:00 2010 -0500
>>>
>>>     In a very sparse environments certain system files (like
>>>     /etc/netconfig) may not exist. In these environments don't
>>>     fail mount if all the need information (like network protocols)
>>>     exist and are well known.
>>>
>>>     Signed-off-by: Steve Dickson<steved@redhat.com>
>>
>> I totally disagree with this.  If HAVE_LIBTIRPC is set, then the  
>> runtime
>> TI-RPC package should be installed, in its entirety, on the run-time
>> systems.  If autoconf and RPM can't trust the given dependency
>> information, then all bets are off.
> Well in some environments "all bets are off" is just not good  
> enough...

Limited disk space does not mean that RPM is suddenly allowed to  
ignore dependencies.  Clearly someone decided that it was OK to  
install only part of the TI-RPC run-time on this system, despite the  
dependency nfs-utils has on libtirpc.

> Mount has always worked in these type of  environments before and
> I think we should continue to...

No one is arguing that point.

>> The right fix is to either:
>>
>> a) install a non-TI-RPC version of mount.nfs, or
>>
>> b) make sure /etc/netconfig is available when RPM, pkgconfig, and
>> autoconf say it should be.
>>
> Sparse environments generally have a finite amount of space, that
> is simple unchangeable... so the above "luxuries" are simply not
> available...

I'm sorry you feel that /etc/netconfig is a luxury, but the fact is  
it's currently a mandatory part of the TI-RPC run-time.  Why be  
surprised if TI-RPC based applications stop working when the run-time  
they depend on is incorrectly installed?

If /etc/rpc and /etc/protocols are installed on this system, then  
there's no reason to exclude /etc/netconfig.  The file is all of 768  
bytes (and can be made smaller immediately by leaving out the block  
comment at the top).  If there really is no room for an additional  
file, then you need a different solution (see below).

Frankly, if disk space is so tight on this system, you should embrace  
using the non-TI-RPC mount.nfs, because it's disk footprint is  
significantly smaller than the current TI-RPC based mount.nfs, and you  
get exactly the functionality that you get with your patch applied.

>> I assume since you are not patching other parts of mount.nfs that  
>> look
>> for /etc/rpc and /etc/protocols that these files _do_ exist?  Or does
>> glibc also do this hack of filling in well-known values?
>>
> Lets keep this in perspective... the "well-known" values in this patch
> things like TCP and UDP... when protocol == IPPROTO_TCP the well  
> known value
> is "tcp" (or "tcp6" depending on the family)... Values that have not
> changed for years and will not change for years...
>
> On the umount side, the file should not be consulted in the first  
> place
> since all the information needed in /etc/mtab... Of course things
> can change between mount and umounts but I truly do no think the
> meaning of "udp" will change from being IPPROTO_UDP....
>
> Making mount more bullet proof and allowing it (continue to) work in  
> all
> different types of environments is a good thing... imho...

You've fundamentally misunderstood my objection to your patch.

In nfs-utils, we've replaced the glibc RPC implementation with TI- 
RPC.  Today, if you want the TI-RPC versions of these utilities to  
"just work" then the whole TI-RPC run-time must be installed on the  
target systems.  Note well that the TI-RPC enabled statd will also  
fail to start if /etc/netconfig does not exist, and this will cause  
NFS mounts to fail as well.  Likewise, a TI-RPC enabled mountd will  
fail to start in this situation.

Now, if you want to ensure that TI-RPC applications will continue to  
work in the absence of parts of the TI-RPC run-time, then you should  
address that in libtirpc, not in every application that uses it.  /etc/ 
netconfig is not a part of mount.nfs, it's a part of TI-RPC.

It also appears that your new logic might assume the values of "tcp"  
and "udp" when an admin purposely excludes them from /etc/netconfig.   
What if an admin wants to start only IPv6 listeners for statd, nfsd,  
and mountd?  Somehow, mounting "tcp" and "udp" still work, even though  
we claim in the man page that these are netids, not protocol names.   
That would be a bug.

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Peter Staubach]

Chuck Lever wrote:
> On Jan 27, 2010, at 1:42 PM, Steve Dickson wrote:
>> On 01/27/2010 01:09 PM, Chuck Lever wrote:
>>>> Author: Steve Dickson<steved@redhat.com>
>>>> Date:   Wed Jan 27 11:19:00 2010 -0500
>>>>
>>>>     In a very sparse environments certain system files (like
>>>>     /etc/netconfig) may not exist. In these environments don't
>>>>     fail mount if all the need information (like network protocols)
>>>>     exist and are well known.
>>>>
>>>>     Signed-off-by: Steve Dickson<steved@redhat.com>
>>>
>>> I totally disagree with this.  If HAVE_LIBTIRPC is set, then the runtime
>>> TI-RPC package should be installed, in its entirety, on the run-time
>>> systems.  If autoconf and RPM can't trust the given dependency
>>> information, then all bets are off.
>> Well in some environments "all bets are off" is just not good enough...
> 
> Limited disk space does not mean that RPM is suddenly allowed to ignore
> dependencies.  Clearly someone decided that it was OK to install only
> part of the TI-RPC run-time on this system, despite the dependency
> nfs-utils has on libtirpc.
> 
>> Mount has always worked in these type of  environments before and
>> I think we should continue to...
> 
> No one is arguing that point.
> 
>>> The right fix is to either:
>>>
>>> a) install a non-TI-RPC version of mount.nfs, or
>>>
>>> b) make sure /etc/netconfig is available when RPM, pkgconfig, and
>>> autoconf say it should be.
>>>
>> Sparse environments generally have a finite amount of space, that
>> is simple unchangeable... so the above "luxuries" are simply not
>> available...
> 
> I'm sorry you feel that /etc/netconfig is a luxury, but the fact is it's
> currently a mandatory part of the TI-RPC run-time.  Why be surprised if
> TI-RPC based applications stop working when the run-time they depend on
> is incorrectly installed?
> 
> If /etc/rpc and /etc/protocols are installed on this system, then
> there's no reason to exclude /etc/netconfig.  The file is all of 768
> bytes (and can be made smaller immediately by leaving out the block
> comment at the top).  If there really is no room for an additional file,
> then you need a different solution (see below).
> 
> Frankly, if disk space is so tight on this system, you should embrace
> using the non-TI-RPC mount.nfs, because it's disk footprint is
> significantly smaller than the current TI-RPC based mount.nfs, and you
> get exactly the functionality that you get with your patch applied.
> 
>>> I assume since you are not patching other parts of mount.nfs that look
>>> for /etc/rpc and /etc/protocols that these files _do_ exist?  Or does
>>> glibc also do this hack of filling in well-known values?
>>>
>> Lets keep this in perspective... the "well-known" values in this patch
>> things like TCP and UDP... when protocol == IPPROTO_TCP the well known
>> value
>> is "tcp" (or "tcp6" depending on the family)... Values that have not
>> changed for years and will not change for years...
>>
>> On the umount side, the file should not be consulted in the first place
>> since all the information needed in /etc/mtab... Of course things
>> can change between mount and umounts but I truly do no think the
>> meaning of "udp" will change from being IPPROTO_UDP....
>>
>> Making mount more bullet proof and allowing it (continue to) work in all
>> different types of environments is a good thing... imho...
> 
> You've fundamentally misunderstood my objection to your patch.
> 
> In nfs-utils, we've replaced the glibc RPC implementation with TI-RPC. 
> Today, if you want the TI-RPC versions of these utilities to "just work"
> then the whole TI-RPC run-time must be installed on the target systems. 
> Note well that the TI-RPC enabled statd will also fail to start if
> /etc/netconfig does not exist, and this will cause NFS mounts to fail as
> well.  Likewise, a TI-RPC enabled mountd will fail to start in this
> situation.
> 
> Now, if you want to ensure that TI-RPC applications will continue to
> work in the absence of parts of the TI-RPC run-time, then you should
> address that in libtirpc, not in every application that uses it. 
> /etc/netconfig is not a part of mount.nfs, it's a part of TI-RPC.
> 
> It also appears that your new logic might assume the values of "tcp" and
> "udp" when an admin purposely excludes them from /etc/netconfig.  What
> if an admin wants to start only IPv6 listeners for statd, nfsd, and
> mountd?  Somehow, mounting "tcp" and "udp" still work, even though we
> claim in the man page that these are netids, not protocol names.  That
> would be a bug.
> 

Chuck, it feels as if you are under the impression that this
is a general purpose deployment that Steve is attempting to
make to work.  It is not.  It is a very restricted use, ie.
to install a system.  Thus, the resources available are very
restricted.  The restriction is not diskspace, per se, but
the memory footprint which would be required to hold it.

The suggestion to use the non-TI-RPC version is interesting,
but has some very negative ramifications.  It would mean that
we would have to test the TI-RPC flavor and the non-TI-RPC
flavor.  It would also limit future development to that which
could be supported via the non-TI-RPC version.  This seems
unnecessarily limiting.

While I don't agree with what the anaconda folks have done,
picking and choosing as they have, they have done so.  I
think that we should work with them to figure out why they
have chosen to do so and whether it is valid or not.

All that said, what is the technical problem with including
this support?  There is no possibility that "tcp" or "udp"
will ever change meaning, at least not in our lifetimes.

The bottom line is that I could agree, that this isn't the
most aesthetically pleasing architecture and implementation.
However, sometimes, the code must run in a non-perfect
world and hence, compromises must be made.

	Thanx...

		ps

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[J. Bruce Fields]

On Wed, Jan 27, 2010 at 05:30:54PM -0500, Peter Staubach wrote:
> Chuck, it feels as if you are under the impression that this
> is a general purpose deployment that Steve is attempting to
> make to work.  It is not.  It is a very restricted use, ie.
> to install a system.  Thus, the resources available are very
> restricted.  The restriction is not diskspace, per se, but
> the memory footprint which would be required to hold it.

The memory footprint for /etc/netconfig?  What are the numbers here?  Is
this a real problem?  And couldn't you get most of the savings as Chuck
suggests just by removing the comments from /etc/netconfig?

> The suggestion to use the non-TI-RPC version is interesting,
> but has some very negative ramifications.  It would mean that
> we would have to test the TI-RPC flavor and the non-TI-RPC
> flavor.  It would also limit future development to that which
> could be supported via the non-TI-RPC version.  This seems
> unnecessarily limiting.
> 
> While I don't agree with what the anaconda folks have done,
> picking and choosing as they have, they have done so.  I
> think that we should work with them to figure out why they
> have chosen to do so and whether it is valid or not.

OK.

> All that said, what is the technical problem with including
> this support?  There is no possibility that "tcp" or "udp"
> will ever change meaning, at least not in our lifetimes.
> 
> The bottom line is that I could agree, that this isn't the
> most aesthetically pleasing architecture and implementation.
> However, sometimes, the code must run in a non-perfect
> world and hence, compromises must be made.

If we have to have this hack, I also wonder (with Chuck) why the same
hack couldn't be done in libtirpc itself.

--b.

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Chuck Lever]

Hi Peter-

On Jan 27, 2010, at 5:30 PM, Peter Staubach wrote:
> Chuck Lever wrote:
>> On Jan 27, 2010, at 1:42 PM, Steve Dickson wrote:
>>> On 01/27/2010 01:09 PM, Chuck Lever wrote:
>>>>> Author: Steve Dickson<steved@redhat.com>
>>>>> Date:   Wed Jan 27 11:19:00 2010 -0500
>>>>>
>>>>>    In a very sparse environments certain system files (like
>>>>>    /etc/netconfig) may not exist. In these environments don't
>>>>>    fail mount if all the need information (like network protocols)
>>>>>    exist and are well known.
>>>>>
>>>>>    Signed-off-by: Steve Dickson<steved@redhat.com>
>>>>
>>>> I totally disagree with this.  If HAVE_LIBTIRPC is set, then the  
>>>> runtime
>>>> TI-RPC package should be installed, in its entirety, on the run- 
>>>> time
>>>> systems.  If autoconf and RPM can't trust the given dependency
>>>> information, then all bets are off.
>>> Well in some environments "all bets are off" is just not good  
>>> enough...
>>
>> Limited disk space does not mean that RPM is suddenly allowed to  
>> ignore
>> dependencies.  Clearly someone decided that it was OK to install only
>> part of the TI-RPC run-time on this system, despite the dependency
>> nfs-utils has on libtirpc.
>>
>>> Mount has always worked in these type of  environments before and
>>> I think we should continue to...
>>
>> No one is arguing that point.
>>
>>>> The right fix is to either:
>>>>
>>>> a) install a non-TI-RPC version of mount.nfs, or
>>>>
>>>> b) make sure /etc/netconfig is available when RPM, pkgconfig, and
>>>> autoconf say it should be.
>>>>
>>> Sparse environments generally have a finite amount of space, that
>>> is simple unchangeable... so the above "luxuries" are simply not
>>> available...
>>
>> I'm sorry you feel that /etc/netconfig is a luxury, but the fact is  
>> it's
>> currently a mandatory part of the TI-RPC run-time.  Why be  
>> surprised if
>> TI-RPC based applications stop working when the run-time they  
>> depend on
>> is incorrectly installed?
>>
>> If /etc/rpc and /etc/protocols are installed on this system, then
>> there's no reason to exclude /etc/netconfig.  The file is all of 768
>> bytes (and can be made smaller immediately by leaving out the block
>> comment at the top).  If there really is no room for an additional  
>> file,
>> then you need a different solution (see below).
>>
>> Frankly, if disk space is so tight on this system, you should embrace
>> using the non-TI-RPC mount.nfs, because it's disk footprint is
>> significantly smaller than the current TI-RPC based mount.nfs, and  
>> you
>> get exactly the functionality that you get with your patch applied.
>>
>>>> I assume since you are not patching other parts of mount.nfs that  
>>>> look
>>>> for /etc/rpc and /etc/protocols that these files _do_ exist?  Or  
>>>> does
>>>> glibc also do this hack of filling in well-known values?
>>>>
>>> Lets keep this in perspective... the "well-known" values in this  
>>> patch
>>> things like TCP and UDP... when protocol == IPPROTO_TCP the well  
>>> known
>>> value
>>> is "tcp" (or "tcp6" depending on the family)... Values that have not
>>> changed for years and will not change for years...
>>>
>>> On the umount side, the file should not be consulted in the first  
>>> place
>>> since all the information needed in /etc/mtab... Of course things
>>> can change between mount and umounts but I truly do no think the
>>> meaning of "udp" will change from being IPPROTO_UDP....
>>>
>>> Making mount more bullet proof and allowing it (continue to) work  
>>> in all
>>> different types of environments is a good thing... imho...
>>
>> You've fundamentally misunderstood my objection to your patch.
>>
>> In nfs-utils, we've replaced the glibc RPC implementation with TI- 
>> RPC.
>> Today, if you want the TI-RPC versions of these utilities to "just  
>> work"
>> then the whole TI-RPC run-time must be installed on the target  
>> systems.
>> Note well that the TI-RPC enabled statd will also fail to start if
>> /etc/netconfig does not exist, and this will cause NFS mounts to  
>> fail as
>> well.  Likewise, a TI-RPC enabled mountd will fail to start in this
>> situation.
>>
>> Now, if you want to ensure that TI-RPC applications will continue to
>> work in the absence of parts of the TI-RPC run-time, then you should
>> address that in libtirpc, not in every application that uses it.
>> /etc/netconfig is not a part of mount.nfs, it's a part of TI-RPC.
>>
>> It also appears that your new logic might assume the values of  
>> "tcp" and
>> "udp" when an admin purposely excludes them from /etc/netconfig.   
>> What
>> if an admin wants to start only IPv6 listeners for statd, nfsd, and
>> mountd?  Somehow, mounting "tcp" and "udp" still work, even though we
>> claim in the man page that these are netids, not protocol names.   
>> That
>> would be a bug.
>
> Chuck, it feels as if you are under the impression that this
> is a general purpose deployment that Steve is attempting to
> make to work.  It is not.  It is a very restricted use, ie.
> to install a system.

This request was made to the upstream maintainer and he has passed it  
to the community, thus someone thought it might have generic interest  
(or, perhaps they just wanted someone else to maintain this hack).

If we are to maintain this new behavior, we (not being the original  
authors) should attempt to understand what is required, and try to fit  
this into our plans and the provided code and APIs.  Unfortunately  
there were very few details offered in the patch description, so we  
are left to assume.

> Thus, the resources available are very
> restricted.  The restriction is not diskspace, per se, but
> the memory footprint which would be required to hold it.
>
> The suggestion to use the non-TI-RPC version is interesting,
> but has some very negative ramifications.  It would mean that
> we would have to test the TI-RPC flavor and the non-TI-RPC
> flavor.  It would also limit future development to that which
> could be supported via the non-TI-RPC version.  This seems
> unnecessarily limiting.
>
> While I don't agree with what the anaconda folks have done,
> picking and choosing as they have, they have done so.  I
> think that we should work with them to figure out why they
> have chosen to do so and whether it is valid or not.
>
> All that said, what is the technical problem with including
> this support?  There is no possibility that "tcp" or "udp"
> will ever change meaning, at least not in our lifetimes.

If this is for Anaconda, I assume that eventually they will want to  
support NFS/IPv6, so we are going to have to make user space TI-RPC  
work in a restricted environment.

The technical issues are:

1.  /etc/netconfig is a mandatory part of TI-RPC (as it is currently  
implemented), so not having it means that the library _will_ be broken  
in all kinds of ways.  That must be addressed if we want our TI-RPC- 
based tools to operate without /etc/netconfig.

2.  All TI-RPC applications that run in a restricted environment will  
have the same problem.  Thus the problem should be addressed in TI- 
RPC, not in any particular application that uses it.  That would  
affect rpcbind, statd, ypbind, showmount, and maybe others.

3.  The absence of a particular netid has specific semantics.  You  
can't just assume "tcp" if there's no "tcp" netid in the /etc/ 
netconfig file.  It doesn't matter how traditional the string "tcp" is  
-- that's simply not the way this API works.

4.  We've changed mount.nfs to make "proto=" take a netid, not a  
protocol name without deference to an address family.  We are now  
being asked to go back to the original behavior, which was that "tcp"  
means either tcp over IPv4 or over IPv6.

> The bottom line is that I could agree, that this isn't the
> most aesthetically pleasing architecture and implementation.
> However, sometimes, the code must run in a non-perfect
> world and hence, compromises must be made.

I should have said "I totally disagree with this _approach_."  I don't  
have a problem with supporting a restricted environment.  But we do  
need to understand what is required first.  In general, there's no  
possible way we can take a significant feature change and support it  
if we don't understand how it's supposed to work.

My current proposal to address this problem is to emulate the contents  
of /etc/netconfig inside libtirpc (specifically in the set/ 
endnetconfigent code) if the /etc/netconfig file does not exist.  The  
emulated contents of the file would essentially match the semantics of  
what we have soldered into the kernel.

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Chuck Lever]

On Jan 27, 2010, at 5:30 PM, Peter Staubach wrote:
> While I don't agree with what the anaconda folks have done,
> picking and choosing as they have, they have done so.  I
> think that we should work with them to figure out why they
> have chosen to do so and whether it is valid or not.

If it wasn't clear from my previous e-mail, I think this is a very  
good idea.

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com

Re: [PATCH] mount.nfs: Don't fail mounts when /etc/netconfig is nonexistent

[Steve Dickson]

On 01/27/2010 03:57 PM, Chuck Lever wrote:
> On Jan 27, 2010, at 1:42 PM, Steve Dickson wrote:
>> On 01/27/2010 01:09 PM, Chuck Lever wrote:
>>>> Author: Steve Dickson<steved@redhat.com>
>>>> Date:   Wed Jan 27 11:19:00 2010 -0500
>>>>
>>>>     In a very sparse environments certain system files (like
>>>>     /etc/netconfig) may not exist. In these environments don't
>>>>     fail mount if all the need information (like network protocols)
>>>>     exist and are well known.
>>>>
>>>>     Signed-off-by: Steve Dickson<steved@redhat.com>
>>>
>>> I totally disagree with this.  If HAVE_LIBTIRPC is set, then the runtime
>>> TI-RPC package should be installed, in its entirety, on the run-time
>>> systems.  If autoconf and RPM can't trust the given dependency
>>> information, then all bets are off.
>> Well in some environments "all bets are off" is just not good enough...
> 
> Limited disk space does not mean that RPM is suddenly allowed to ignore
> dependencies.  Clearly someone decided that it was OK to install only
> part of the TI-RPC run-time on this system, despite the dependency
> nfs-utils has on libtirpc.
This has been a practice (cherry picking pieces from RPMS) for a 
very long time (so I'm told)....
 
> 
>> Mount has always worked in these type of  environments before and
>> I think we should continue to...
> 
> No one is arguing that point.
> 
>>> The right fix is to either:
>>>
>>> a) install a non-TI-RPC version of mount.nfs, or
>>>
>>> b) make sure /etc/netconfig is available when RPM, pkgconfig, and
>>> autoconf say it should be.
>>>
>> Sparse environments generally have a finite amount of space, that
>> is simple unchangeable... so the above "luxuries" are simply not
>> available...
> 
> I'm sorry you feel that /etc/netconfig is a luxury, but the fact is it's
> currently a mandatory part of the TI-RPC run-time.  Why be surprised if
> TI-RPC based applications stop working when the run-time they depend on
> is incorrectly installed?
> 
> If /etc/rpc and /etc/protocols are installed on this system, then
> there's no reason to exclude /etc/netconfig.  The file is all of 768
> bytes (and can be made smaller immediately by leaving out the block
> comment at the top).  If there really is no room for an additional file,
> then you need a different solution (see below).
/etc/protocols is but /etc/rpc is not.

> 
> Frankly, if disk space is so tight on this system, you should embrace
> using the non-TI-RPC mount.nfs, because it's disk footprint is
> significantly smaller than the current TI-RPC based mount.nfs, and you
> get exactly the functionality that you get with your patch applied.
I don't think supporting two different packages is the answer...

> 
>>> I assume since you are not patching other parts of mount.nfs that look
>>> for /etc/rpc and /etc/protocols that these files _do_ exist?  Or does
>>> glibc also do this hack of filling in well-known values?
>>>
>> Lets keep this in perspective... the "well-known" values in this patch
>> things like TCP and UDP... when protocol == IPPROTO_TCP the well known
>> value
>> is "tcp" (or "tcp6" depending on the family)... Values that have not
>> changed for years and will not change for years...
>>
>> On the umount side, the file should not be consulted in the first place
>> since all the information needed in /etc/mtab... Of course things
>> can change between mount and umounts but I truly do no think the
>> meaning of "udp" will change from being IPPROTO_UDP....
>>
>> Making mount more bullet proof and allowing it (continue to) work in all
>> different types of environments is a good thing... imho...
> 
> You've fundamentally misunderstood my objection to your patch.
> 
> In nfs-utils, we've replaced the glibc RPC implementation with TI-RPC. 
> Today, if you want the TI-RPC versions of these utilities to "just work"
> then the whole TI-RPC run-time must be installed on the target systems. 
> Note well that the TI-RPC enabled statd will also fail to start if
> /etc/netconfig does not exist, and this will cause NFS mounts to fail as
> well.  Likewise, a TI-RPC enabled mountd will fail to start in this
> situation.
The -o nolock option used so statd or rpcbind, for that matter, is not needed...

> 
> Now, if you want to ensure that TI-RPC applications will continue to
> work in the absence of parts of the TI-RPC run-time, then you should
> address that in libtirpc, not in every application that uses it. 
> /etc/netconfig is not a part of mount.nfs, it's a part of TI-RPC.
Technically I see no difference whether its done in the mount command
or library... theoretically I think it makes more sense to leave it
up to the applications to decide if they want to fail if /etc/netconfig
does not exist... Why should a library make that type of assumption
on behalf of an application?
  
> 
> It also appears that your new logic might assume the values of "tcp" and
> "udp" when an admin purposely excludes them from /etc/netconfig.  What
> if an admin wants to start only IPv6 listeners for statd, nfsd, and
> mountd?  Somehow, mounting "tcp" and "udp" still work, even though we
> claim in the man page that these are netids, not protocol names.  That
> would be a bug.
If values are read out /etc/netconfig, this code will not be deployed...
that's now people can setup IPv6 only listeners... 


steved.