----- Original Message ----- > From: "Jeff Layton" <jlayton@xxxxxxxxxxxxxxx> > To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> > Cc: linux-nfs@xxxxxxxxxxxxxxx, "Tom Haynes" <thomas.haynes@xxxxxxxxxxxxxxx>, "Christoph Hellwig" <hch@xxxxxx> > Sent: Monday, May 30, 2016 6:51:38 PM > Subject: Re: [RFC PATCH] nfsd: allow nfsd to advertise multiple layout types > On Mon, 2016-05-30 at 17:47 +0200, Mkrtchyan, Tigran wrote: >> >> ----- Original Message ----- >> > From: "Jeff Layton" <jlayton@xxxxxxxxxxxxxxx> >> > To: linux-nfs@xxxxxxxxxxxxxxx >> > Cc: "Tom Haynes" <thomas.haynes@xxxxxxxxxxxxxxx>, "Christoph Hellwig" >> > <hch@xxxxxx> >> > 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@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; >> > > } >> > >> > >> > 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. >> > > Thanks. I had already rolled one up that does a different approach of a > hardcoded selection order in the client code and sent it as an RFC. > > So...yours assumes that the server will send the "default" one first in > the list, but AFAICT, the spec doesn't say anything about the > fs_layout_type list being ordered in any way. I don't think we can make > that assumption. Am I wrong there? Imagine a muti-layout server in a deployment, where some client are old (RHEL6) and some clients are new. RHEL6 will always take only the first one and fail, if it wasn't nfs4_file_layout. But, if we always return 'well-known' as a first one, then, then RHEL6 clients will be able to coexists with newer clients. Our server can provide flexfile layouts, but 99% of our clients are RHEL6-clones. This stops us from enable flexfile support, unless we add per-client based control of layout type. Tigran. > > What we probably ought to do is to plumb the selection in at a > different layer -- i.e., when you go to actually do the I/O. That way, > you could get a SCSI or block layout, figure out that you don't > actually have access to the device and fall back to using flexfiles or > files. > -- > Jeff Layton <jlayton@xxxxxxxxxxxxxxx> > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html