Re: [PATCH RFC v0 07/49] pnfsd: add pnfs export option

[Benny Halevy <bhalevy@primarydata.com>]

On 2013-09-27 17:36, J. Bruce Fields wrote:
> Is this really necessary?  What would we lose if we just used pnfs
> automatically when the filesystem supports it and all other necessary
> configuration is in place?

We can do that and let the client decide whether to use pnfs or not.
Though I think that to deal with client interoperability issues, one
would want to control that.  If we don't provide a way to enable/disable
pnfs at the export level every file system that supports pnfs would probably
need a mount option to control pnfs exportability...

Benny

> 
> On Thu, Sep 26, 2013 at 02:40:19PM -0400, Benny Halevy wrote:
>> From: Andy Adamson <andros@netapp.com>
>>
>> This is a boolean for now. When more layouttypes are supported, this can
>> change to "pnfs=", similar to "sec=".
>>
>> The ctl interface is not enhanced.
>>
>> Note: Export option strings are not guaranteed to be present in every call to
>> svc_export_parse. For example, nfs-utils-1.1.2 exportfs validates the export
>> with a test call that does not include the 'pnfs' export option even though
>> it is set in /etc/exports.
>>
>> nfsd4_layout_verify() checks if ex_pnfs is set so the ex_pnfs check in
>> check_export is not needed.
>>
>> Furthermore,the pnfs_export_operations super block pointer should not be
>> changed because a) it is a const and b) the exports options can be changed
>> while the file system is mounted.
>>
>> Remove the ex_pnfs check from check_export to prevent the pnfs_export_operations
>> superblock pointer from being set to NULL.
> 
> This patch doesn't touch check_export.  Is this describing a change from
> a previous version of the patch?  If so, either drop this comment or
> write it in a way that will make sense to someone who hasn't seen the
> previous version.
> 
> --b.
> 
> 
>>
>> Signed-off-by: Andy Adamson <andros@netapp.com>
>> [pnfsd: fix cosmetic checkpatch warnings]
>> [pnfsd: test pnfs export option in check_export]
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> [pnfsd: fix ex_pnfs check_export bug]
>> Signed-off-by: Andy Adamson <andros@netapp.com>
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> Signed-off-by: Benny Halevy <bhalevy@primarydata.com>
>> ---
>>  fs/nfsd/export.c            | 6 ++++++
>>  include/linux/nfsd/export.h | 1 +
>>  2 files changed, 7 insertions(+)
>>
>> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
>> index f26b0b9..7730dfd 100644
>> --- a/fs/nfsd/export.c
>> +++ b/fs/nfsd/export.c
>> @@ -567,6 +567,8 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
>>  					if (exp.ex_uuid == NULL)
>>  						err = -ENOMEM;
>>  				}
>> +			} else if (strcmp(buf, "pnfs") == 0) {
>> +				exp.ex_pnfs = 1;
>>  			} else if (strcmp(buf, "secinfo") == 0)
>>  				err = secinfo_parse(&mesg, buf, &exp);
>>  			else
>> @@ -639,6 +641,8 @@ static int svc_export_show(struct seq_file *m,
>>  				seq_printf(m, "%02x", exp->ex_uuid[i]);
>>  			}
>>  		}
>> +		if (exp->ex_pnfs)
>> +			seq_puts(m, ",pnfs");
>>  		show_secinfo(m, exp);
>>  	}
>>  	seq_puts(m, ")\n");
>> @@ -666,6 +670,7 @@ static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)
>>  	new->ex_fslocs.locations_count = 0;
>>  	new->ex_fslocs.migrated = 0;
>>  	new->ex_uuid = NULL;
>> +	new->ex_pnfs = 0;
>>  	new->cd = item->cd;
>>  }
>>  
>> @@ -679,6 +684,7 @@ static void export_update(struct cache_head *cnew, struct cache_head *citem)
>>  	new->ex_anon_uid = item->ex_anon_uid;
>>  	new->ex_anon_gid = item->ex_anon_gid;
>>  	new->ex_fsid = item->ex_fsid;
>> +	new->ex_pnfs = item->ex_pnfs;
>>  	new->ex_uuid = item->ex_uuid;
>>  	item->ex_uuid = NULL;
>>  	new->ex_fslocs.locations = item->ex_fslocs.locations;
>> diff --git a/include/linux/nfsd/export.h b/include/linux/nfsd/export.h
>> index 7898c99..b03ceee 100644
>> --- a/include/linux/nfsd/export.h
>> +++ b/include/linux/nfsd/export.h
>> @@ -52,6 +52,7 @@ struct svc_export {
>>  	kuid_t			ex_anon_uid;
>>  	kgid_t			ex_anon_gid;
>>  	int			ex_fsid;
>> +	int			ex_pnfs;
>>  	unsigned char *		ex_uuid; /* 16 byte fsid */
>>  	struct nfsd4_fs_locations ex_fslocs;
>>  	int			ex_nflavors;
>> -- 
>> 1.8.3.1
>>