Re: [RFC PATCH] nfsd: allow nfsd to advertise multiple layout types

["Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>]

----- Original Message -----
> From: "Jeff Layton" <jlayton@poochiereds.net>
> To: linux-nfs@vger.kernel.org
> Cc: "Tom Haynes" <thomas.haynes@primarydata.com>, "Christoph Hellwig" <hch@lst.de>
> Sent: Sunday, May 29, 2016 11:06:14 PM
> Subject: Re: [RFC PATCH] nfsd: allow nfsd to advertise multiple layout types

> On Sun, 2016-05-29 at 16:59 -0400, Jeff Layton wrote:
>> If the underlying filesystem supports multiple layout types, then there
>> is little reason not to advertise that fact to clients and let them
>> choose what type to use.
>> 
>> Turn the ex_layout_type field into a bitfield. For each supported
>> layout type, we set a bit in that field. When the client requests a
>> layout, ensure that the bit for that layout type is set. When the
>> client requests attributes, send back a list of supported types.
>> 
>> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
>> ---
>>  fs/nfsd/export.c      |  4 ++--
>>  fs/nfsd/export.h      |  2 +-
>>  fs/nfsd/nfs4layouts.c |  6 +++---
>>  fs/nfsd/nfs4proc.c    |  4 ++--
>>  fs/nfsd/nfs4xdr.c     | 30 ++++++++++++++----------------
>>  5 files changed, 22 insertions(+), 24 deletions(-)
>> 
>> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
>> index b4d84b579f20..f97ba49d5e66 100644
>> --- a/fs/nfsd/export.c
>> +++ b/fs/nfsd/export.c
>> @@ -706,7 +706,7 @@ static void svc_export_init(struct cache_head *cnew, struct
>> cache_head *citem)
>>  	new->ex_fslocs.locations = NULL;
>>  	new->ex_fslocs.locations_count = 0;
>>  	new->ex_fslocs.migrated = 0;
>> -	new->ex_layout_type = 0;
>> +	new->ex_layout_types = 0;
>>  	new->ex_uuid = NULL;
>>  	new->cd = item->cd;
>>  }
>> @@ -731,7 +731,7 @@ static void export_update(struct cache_head *cnew, struct
>> cache_head *citem)
>>  	item->ex_fslocs.locations_count = 0;
>>  	new->ex_fslocs.migrated = item->ex_fslocs.migrated;
>>  	item->ex_fslocs.migrated = 0;
>> -	new->ex_layout_type = item->ex_layout_type;
>> +	new->ex_layout_types = item->ex_layout_types;
>>  	new->ex_nflavors = item->ex_nflavors;
>>  	for (i = 0; i < MAX_SECINFO_LIST; i++) {
>>  		new->ex_flavors[i] = item->ex_flavors[i];
>> diff --git a/fs/nfsd/export.h b/fs/nfsd/export.h
>> index 2e315072bf3f..730f15eeb7ed 100644
>> --- a/fs/nfsd/export.h
>> +++ b/fs/nfsd/export.h
>> @@ -57,7 +57,7 @@ struct svc_export {
>>  	struct nfsd4_fs_locations ex_fslocs;
>>  	uint32_t		ex_nflavors;
>>  	struct exp_flavor_info	ex_flavors[MAX_SECINFO_LIST];
>> -	enum pnfs_layouttype	ex_layout_type;
>> +	u32			ex_layout_types;
>>  	struct nfsd4_deviceid_map *ex_devid_map;
>>  	struct cache_detail	*cd;
>>  };
>> diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
>> index 6d98d16b3354..2be9602b0221 100644
>> --- a/fs/nfsd/nfs4layouts.c
>> +++ b/fs/nfsd/nfs4layouts.c
>> @@ -139,21 +139,21 @@ void nfsd4_setup_layout_type(struct svc_export *exp)
>>  	 * otherwise advertise the block layout.
>>  	 */
>>  #ifdef CONFIG_NFSD_FLEXFILELAYOUT
>> -	exp->ex_layout_type = LAYOUT_FLEX_FILES;
>> +	exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
>>  #endif
>>  #ifdef CONFIG_NFSD_BLOCKLAYOUT
>>  	/* overwrite flex file layout selection if needed */
>>  	if (sb->s_export_op->get_uuid &&
>>  	    sb->s_export_op->map_blocks &&
>>  	    sb->s_export_op->commit_blocks)
>> -		exp->ex_layout_type = LAYOUT_BLOCK_VOLUME;
>> +		exp->ex_layout_types |= 1 << LAYOUT_BLOCK_VOLUME;
>>  #endif
>>  #ifdef CONFIG_NFSD_SCSILAYOUT
>>  	/* overwrite block layout selection if needed */
>>  	if (sb->s_export_op->map_blocks &&
>>  	    sb->s_export_op->commit_blocks &&
>>  	    sb->s_bdev && sb->s_bdev->bd_disk->fops->pr_ops)
>> -		exp->ex_layout_type = LAYOUT_SCSI;
>> +		exp->ex_layout_types |= 1 << LAYOUT_SCSI;
>>  #endif
>>  }
>>  
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index 2ee2dc170327..719c620753e2 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -1219,12 +1219,12 @@ nfsd4_verify(struct svc_rqst *rqstp, struct
>> nfsd4_compound_state *cstate,
>>  static const struct nfsd4_layout_ops *
>>  nfsd4_layout_verify(struct svc_export *exp, unsigned int layout_type)
>>  {
>> -	if (!exp->ex_layout_type) {
>> +	if (!exp->ex_layout_types) {
>>  		dprintk("%s: export does not support pNFS\n", __func__);
>>  		return NULL;
>>  	}
>>  
>> -	if (exp->ex_layout_type != layout_type) {
>> +	if (!(exp->ex_layout_types & (1 << layout_type))) {
>>  		dprintk("%s: layout type %d not supported\n",
>>  			__func__, layout_type);
>>  		return NULL;
>> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
>> index 9df898ba648f..4d3ae75ad4c8 100644
>> --- a/fs/nfsd/nfs4xdr.c
>> +++ b/fs/nfsd/nfs4xdr.c
>> @@ -2164,22 +2164,20 @@ nfsd4_encode_aclname(struct xdr_stream *xdr, struct
>> svc_rqst *rqstp,
>>  }
>>  
>>  static inline __be32
>> -nfsd4_encode_layout_type(struct xdr_stream *xdr, enum pnfs_layouttype
>> layout_type)
>> +nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
>>  {
>> -	__be32 *p;
>> +	__be32		*p;
>> +	unsigned long	i = hweight_long(layout_types);
>>  
>> -	if (layout_type) {
>> -		p = xdr_reserve_space(xdr, 8);
>> -		if (!p)
>> -			return nfserr_resource;
>> -		*p++ = cpu_to_be32(1);
>> -		*p++ = cpu_to_be32(layout_type);
>> -	} else {
>> -		p = xdr_reserve_space(xdr, 4);
>> -		if (!p)
>> -			return nfserr_resource;
>> -		*p++ = cpu_to_be32(0);
>> -	}
>> +	p = xdr_reserve_space(xdr, 4 + 4 * i);
>> +	if (!p)
>> +		return nfserr_resource;
>> +
>> +	*p++ = cpu_to_be32(i);
>> +
>> +	for (i = LAYOUT_NFSV4_1_FILES; i < LAYOUT_TYPE_MAX; ++i)
>> +		if (layout_types & (1 << i))
>> +			*p++ = cpu_to_be32(i);
>>  
>>  	return 0;
>>  }
>> @@ -2754,13 +2752,13 @@ out_acl:
>>  	}
>>  #ifdef CONFIG_NFSD_PNFS
>>  	if (bmval1 & FATTR4_WORD1_FS_LAYOUT_TYPES) {
>> -		status = nfsd4_encode_layout_type(xdr, exp->ex_layout_type);
>> +		status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
>>  		if (status)
>>  			goto out;
>>  	}
>>  
>>  	if (bmval2 & FATTR4_WORD2_LAYOUT_TYPES) {
>> -		status = nfsd4_encode_layout_type(xdr, exp->ex_layout_type);
>> +		status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
>>  		if (status)
>>  			goto out;
>>  	}
> 
> 
> Just a (lightly-tested) RFC patch for now.
> 
> This seems to do the right thing WRT to GETATTR response that requests
> a layout types list. The current client code spews this into the ring
> buffer though:
> 
>    NFS: decode_first_pnfs_layout_type: Warning: Multiple pNFS layout drivers per
>    filesystem not supported
> 
> ...so that would need a little work. Wireshark also seems to not parse
> the layout types list correctly.

Hi Jeff,

I had an attempt to add multi-layout support into the client:

https://github.com/0day-ci/linux/commit/e2d792dc32b82ffc511b009c0a8db5313126888e

I can't find it in the list archive. This explains why Trond never
respond to it.

Tigran.


> 
> Thoughts?
> --
> Jeff Layton <jlayton@poochiereds.net>
> --
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