On Wed, 2016-06-15 at 16:44 -0400, J. Bruce Fields wrote:
> On Wed, Jun 15, 2016 at 02:33:09PM -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.
> Not sure it matters, but just to make sure I understand:
>
> This will return the layout types in numerical order (blocks,
> flex_files, scsi)
>
Yes. We could try to game that somehow, but I'm not sure that's really
a reasonable strategy long-term.
> That means current & older clients will choose blocks over flex_files,
> flex_files over scsi--not really what we want, but we can control that
> at build time by compiling out types we don't want. And clients after
> your patches will instead choose in client preference order.
>
> I think I'm OK with that.
>
Yeah, that's the idea. I think it's really the best we can do given the
way that the client has worked up until these patches. Over time, newer
clients should proliferate and this should become a non-issue (in
theory!). If we find that it is a problem, we could also add export
options to control the order (or force a single layout type for an
export).
I don't think committing the server-side patches now will likely cause
problems, but it might be good to see what the client maintainers think
before we make any moves. I'd hate to make a server side change until
we have a better idea of what they think.
Trond, Anna? Care to comment on this set?
> >
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
> > Reviewed-by: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>
> > ---
> > 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;
> > }
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
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