[pnfs] [PATCH 1/3] pnfs-gfs2: initial LAYOUT* work for pNFS/GFS2 integration

[Benny Halevy]

On May. 30, 2008, 19:30 +0300, "david m. richter" <richterd at citi.umich.edu> wrote:
> 	thanks for the fixups, dean :)  i had been wondering if/how the 
> "numDests" that we saw in cxiSystem.c was going to affect making the 
> layout filehandles in the gfs2 world, but you took care of that nicely.

FYI: I didn't apply any of Dean's comments.
Please resend the fixed patch (based on the newest version in the tree
please) or a squashable patch with the fixups...

Benny

> 
> 	thanks!
> 
> On Thu, 29 May 2008, Dean Hildebrand wrote:
> 
>>
>> David M. Richter wrote:
>>> Frank Filz's work on the layout_type() and layout_get() export operations,
>>> with stubs for layout_commit() and layout_return().  Tested at Connectathon.
>>>
>>> Signed-off-by: Frank Filz <ffilzlnx at us.ibm.com>
>>> Signed-off-by: David M. Richter <richterd at citi.umich.edu>
>>> ---
>>>  fs/gfs2/ops_export.c |  109
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>  1 files changed, 109 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/fs/gfs2/ops_export.c b/fs/gfs2/ops_export.c
>>> index 334c7f8..b62cc66 100644
>>> --- a/fs/gfs2/ops_export.c
>>> +++ b/fs/gfs2/ops_export.c
>>> @@ -27,6 +27,16 @@
>>>  #include "rgrp.h"
>>>  #include "util.h"
>>>  +#if defined(CONFIG_PNFSD)
>>> +#include <linux/nfs_fs.h>
>>> +#include <linux/sunrpc/svc.h>
>>> +#include <linux/nfsd/state.h>
>>> +#include <linux/nfsd/nfsfh.h>
>>> +#include <linux/nfsd/pnfsd.h>
>>> +#include <linux/nfsd/nfs4layoutxdr.h>
>>> +#include <linux/nfs4_pnfs.h>
>>> +#endif /* CONFIG_PNFSD */
>>> +
>>>  #define GFS2_SMALL_FH_SIZE 4
>>>  #define GFS2_LARGE_FH_SIZE 8
>>>  #define GFS2_OLD_FH_SIZE 10
>>> @@ -294,11 +304,110 @@ static struct dentry *gfs2_fh_to_parent(struct
>>> super_block *sb, struct fid *fid,
>>>  	}
>>>  }
>>>  +#if defined(CONFIG_PNFSD)
>>> +static int gfs2_layout_type(void)
>>> +{
>>> +	return LAYOUT_NFSV4_FILES;
>>> +}
>>> +
>>> +/* like GPFS does, use a multiple of the underlying fs' blocksize */
>>>   
>> no so important now, but in the long run I'd remove any mention of gpfs.
>>> +static int get_stripe_unit(int blocksize)
>>> +{
>>> +	if (blocksize >= NFSSVC_MAXBLKSIZE)
>>> +		return blocksize;
>>> +
>>> +	return NFSSVC_MAXBLKSIZE - NFSSVC_MAXBLKSIZE % blocksize;
>>>   
>> I would add () just to make sure it is clear.
>>> +}
>>> +
>>> +/*
>>> + * Retrieve and encode a file layout onto the xdr stream.
>>> + * @inode: inode for which to retrieve layout
>>> + * @arg->xdr: xdr stream for encoding
>>> + * @arg->func: a call into file system to encode the layout on xdr stream.
>>> + */
>>> +static int gfs2_layout_get(struct inode *inode, struct pnfs_layoutget_arg
>>> *arg)
>>> +{
>>> +	int i, rc = 0;
>>> +	int num_dests = 1; /* XXX: revisit */
>>> +	struct pnfs_filelayout_layout *layout = NULL;
>>> +	struct knfsd_fh *fh_list = NULL;
>>> +
>>> +	printk(KERN_DEBUG "%s: LAYOUT_GET\n", __func__);
>>> +
>>> +	/* Set layout indept response args */
>>> +	arg->seg.layout_type = LAYOUT_NFSV4_FILES;
>>> +	arg->seg.offset = 0;
>>> +	arg->seg.length = inode->i_sb->s_maxbytes; /* The maximum file size */
>>> +
>>> +	layout = kzalloc(sizeof(*layout), GFP_KERNEL);
>>> +	if (layout == NULL) {
>>> +		rc = -ENOMEM;
>>> +		goto error;
>>> +	}
>>> +
>>> +	/* Set file layout response args */
>>> +	layout->lg_layout_type = LAYOUT_NFSV4_FILES;
>>> +	layout->lg_stripe_type = STRIPE_SPARSE;
>>> +	layout->lg_commit_through_mds = true;
>>> +	layout->lg_stripe_unit = get_stripe_unit(inode->i_sb->s_blocksize);
>>> +	layout->lg_fh_length = num_dests;
>>> +	layout->device_id.pnfs_fsid = arg->fsid;
>>> +	layout->device_id.pnfs_devid = 1;			/*FSFTEMP*/
>>> +	layout->lg_first_stripe_index = 0;			/*FSFTEMP*/
>>> +	layout->lg_pattern_offset = 0;
>>> +
>>> +	fh_list = kmalloc(sizeof(*fh_list) * num_dests, GFP_KERNEL);
>>> +	if (fh_list == NULL) {
>>> +		rc = -ENOMEM;
>>> +		goto error;
>>> +	}
>>> +
>>> +	memcpy(&fh_list[0], arg->fh, sizeof(*fh_list));
>>> +	pnfs_fh_mark_ds(&fh_list[0]);
>>> +
>>> +	if (num_dests > 1)
>>> +		for (i = 1; i < num_dests; i++)
>>> +			memcpy(&fh_list[i], &fh_list[0], sizeof(*fh_list));
>>>   
>> We just noticed this in gpfs, but we only need to set 1 file handle.
>>
>> from draft23:
>> nfl_fh_list: An array of data server filehandles for each list of data servers
>> in each element of the nflda_multipath_ds_list array. The number of elements
>> in nfl_fh_list depends on whether sparse or dense packing is being used.
>>
>>    * If sparse packing is being used, the number of elements in
>>      nfl_fh_list MUST be one of three values:
>>          o Zero. This means that filehandles used for each data server
>>            are the same as the filehandle returned by the OPEN
>>            operation from the metadata server.
>>          o One. This means that every data server uses the same
>>            filehandle: what is specified in nfl_fh_list[0].
>>          o The same number of elements in nflda_multipath_ds_list.
>>            Thus, in this case, when issuing an I/O to any data server
>>            in nflda_multipath_ds_list[X], the filehandle in
>>            nfl_fh_list[X] MUST be used.
>>
>>
>>> +	layout->lg_fh_list = fh_list;
>>> +
>>> +	/* Call nfsd to encode layout */
>>> +	rc = arg->func(&arg->xdr, layout);
>>> +exit:
>>> +	kfree(layout);
>>> +	kfree(fh_list);
>>> +	return rc;
>>> +
>>> +error:
>>> +	arg->seg.length = 0;
>>> +	goto exit;
>>> +}
>>> +
>>> +static int gfs2_layout_commit(struct inode *inode, void *p)
>>> +{
>>> +	printk(KERN_DEBUG "%s: LAYOUT_COMMIT (unimplemented)\n", __func__);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int gfs2_layout_return(struct inode *inode, void *p)
>>> +{
>>> +	printk(KERN_DEBUG "%s: LAYOUT_RETURN (unimplemented)\n", __func__);
>>> +
>>> +	return 0;
>>> +}
>>> +#endif /* CONFIG_PNFSD */
>>> +
>>>  const struct export_operations gfs2_export_ops = {
>>>  	.encode_fh = gfs2_encode_fh,
>>>  	.fh_to_dentry = gfs2_fh_to_dentry,
>>>  	.fh_to_parent = gfs2_fh_to_parent,
>>>  	.get_name = gfs2_get_name,
>>>  	.get_parent = gfs2_get_parent,
>>> +#if defined(CONFIG_PNFSD)
>>> +	.layout_type = gfs2_layout_type,
>>> +	.layout_get = gfs2_layout_get,
>>> +	.layout_commit = gfs2_layout_commit,
>>> +	.layout_return = gfs2_layout_return,
>>> +#endif /* CONFIG_PNFSD */
>>>  };
>>>