On Tue, 2015-09-22 at 15:45 +0200, Tigran Mkrtchyan wrote:
> current NFSv4.1/pNFS client assumes that MDS supports
> only one layout type. While it's true for most existing servers,
> nevertheless, this can be change in the near future.
>
> This patch is an attempt to multi layouttype MDS support. To make
> it possible for such servers still function with existing clients,
> the layout
> type list will be processed in reverse order. This gives old clients
> still
> pick the first entry, but newer client will pick last entry. Proof:
>
> 4.3.0-rc1-dirty
> [ 180.868764] nfs4flexfilelayout_init: NFSv4 Flexfile Layout Driver
> Registering...
>
> 2.6.32-573.3.1.el6.x86_64
> nfs4filelayout_init: NFSv4 File Layout Driver Registering...
>
> Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@xxxxxxx>
> ---
> fs/nfs/client.c | 2 +-
> fs/nfs/nfs4xdr.c | 22 +++++++++---------
> fs/nfs/pnfs.c | 62 ++++++++++++++++++++++++++++++---------
> ----------
> fs/nfs/pnfs.h | 2 +-
> include/linux/nfs_xdr.h | 4 +++-
> 5 files changed, 54 insertions(+), 38 deletions(-)
>
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index 57c5a02..1145bc7 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -786,7 +786,7 @@ int nfs_probe_fsinfo(struct nfs_server *server,
> struct nfs_fh *mntfh, struct nfs
> }
>
> fsinfo.fattr = fattr;
> - fsinfo.layouttype = 0;
> + memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
> error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
> if (error < 0)
> goto out_error;
> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
> index 788adf3..7fbd411 100644
> --- a/fs/nfs/nfs4xdr.c
> +++ b/fs/nfs/nfs4xdr.c
> @@ -4688,14 +4688,14 @@ static int decode_getfattr(struct xdr_stream
> *xdr, struct nfs_fattr *fattr,
> }
>
> /*
> - * Decode potentially multiple layout types. Currently we only
> support
> - * one layout driver per file system.
> + * Decode potentially multiple layout types.
> */
> -static int decode_first_pnfs_layout_type(struct xdr_stream *xdr,
> +static int decode_pnfs_layout_types(struct xdr_stream *xdr,
> uint32_t *layouttype)
> {
> __be32 *p;
> int num;
> + int i;
Make these both unsigned int?
>
> p = xdr_inline_decode(xdr, 4);
> if (unlikely(!p))
> @@ -4704,18 +4704,18 @@ static int
> decode_first_pnfs_layout_type(struct xdr_stream *xdr,
>
> /* pNFS is not supported by the underlying file system */
> if (num == 0) {
> - *layouttype = 0;
> return 0;
> }
> - if (num > 1)
> - printk(KERN_INFO "NFS: %s: Warning: Multiple pNFS
> layout "
> - "drivers per filesystem not supported\n",
> __func__);
> + if (num > NFS_MAX_LAYOUT_TYPES)
> + printk(KERN_INFO "NFS: %s: Warning: Too many (%d)
> pNFS layout types\n", __func__, num);
>
> /* Decode and set first layout type, move xdr->p past unused
> types */
> p = xdr_inline_decode(xdr, num * 4);
> if (unlikely(!p))
> goto out_overflow;
> - *layouttype = be32_to_cpup(p);
> + for(i = 0; i < num && i < NFS_MAX_LAYOUT_TYPES; i++) {
> + layouttype[i] = be32_to_cpup(p++);
> + }
You don't need the { } block enclosure here.
> return 0;
> out_overflow:
> print_overflow_msg(__func__, xdr);
> @@ -4735,10 +4735,10 @@ static int decode_attr_pnfstype(struct
> xdr_stream *xdr, uint32_t *bitmap,
> if (unlikely(bitmap[1] & (FATTR4_WORD1_FS_LAYOUT_TYPES -
> 1U)))
> return -EIO;
> if (bitmap[1] & FATTR4_WORD1_FS_LAYOUT_TYPES) {
> - status = decode_first_pnfs_layout_type(xdr,
> layouttype);
> + status = decode_pnfs_layout_types(xdr, layouttype);
> bitmap[1] &= ~FATTR4_WORD1_FS_LAYOUT_TYPES;
> } else
> - *layouttype = 0;
> + memset(layouttype, 0, sizeof(*layouttype));
Isn't this already done by the caller in fs/nfs/client.c?
> return status;
> }
>
> @@ -4792,7 +4792,7 @@ static int decode_fsinfo(struct xdr_stream
> *xdr, struct nfs_fsinfo *fsinfo)
> status = decode_attr_time_delta(xdr, bitmap, &fsinfo
> ->time_delta);
> if (status != 0)
> goto xdr_error;
> - status = decode_attr_pnfstype(xdr, bitmap, &fsinfo
> ->layouttype);
> + status = decode_attr_pnfstype(xdr, bitmap, fsinfo
> ->layouttype);
> if (status != 0)
> goto xdr_error;
> status = decode_attr_layout_blksize(xdr, bitmap, &fsinfo
> ->blksize);
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index ba12464..883bfa2 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -104,45 +104,59 @@ unset_pnfs_layoutdriver(struct nfs_server
> *nfss)
> * Try to set the server's pnfs module to the pnfs layout type
> specified by id.
> * Currently only one pNFS layout driver per filesystem is
> supported.
> *
> - * @id layout type. Zero (illegal layout type) indicates pNFS not in
> use.
> + * @ids array of layout types supported by MDS.
> */
> void
> set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh
> *mntfh,
> - u32 id)
> + u32 *ids)
> {
> struct pnfs_layoutdriver_type *ld_type = NULL;
> + u32 id;
> + int i;
>
> - if (id == 0)
> - goto out_no_driver;
> if (!(server->nfs_client->cl_exchange_flags &
> (EXCHGID4_FLAG_USE_NON_PNFS |
> EXCHGID4_FLAG_USE_PNFS_MDS))) {
> - printk(KERN_ERR "NFS: %s: id %u cl_exchange_flags
> 0x%x\n",
> - __func__, id, server->nfs_client
> ->cl_exchange_flags);
> + printk(KERN_ERR "NFS: %s: cl_exchange_flags 0x%x\n",
> + __func__, server->nfs_client
> ->cl_exchange_flags);
> goto out_no_driver;
> }
> - ld_type = find_pnfs_driver(id);
> - if (!ld_type) {
> - request_module("%s-%u",
> LAYOUT_NFSV4_1_MODULE_PREFIX, id);
> +
> + /*
> + * walk in reverse ordet to use last in the list first.
> + * By assyming, that server will send most common type
> first,
> + * most preferred one last, old client will be happy with
> + * a first entry, where new clients (4.4+) will pick the
> + * most advance one.
This implies that old clients will always pick the least preferred
layout type from the server's perspective. Ditto if newer clients get
the value of NFS_MAX_LAYOUT_TYPES wrong.
Why not instead assume the following? 1st entry == default. Others are
sorted in order of decreasing server preference.
> + */
> + for(i = NFS_MAX_LAYOUT_TYPES; i >=0; i--) {
> + id = ids[i];
> + if(!id)
> + continue;
> +
> ld_type = find_pnfs_driver(id);
> if (!ld_type) {
> - dprintk("%s: No pNFS module found for
> %u.\n",
> - __func__, id);
> + request_module("%s-%u",
> LAYOUT_NFSV4_1_MODULE_PREFIX, id);
> + ld_type = find_pnfs_driver(id);
> + if (!ld_type) {
> + dprintk("%s: No pNFS module found
> for %u.\n",
> + __func__, id);
> + continue;
> + }
> + }
> + server->pnfs_curr_ld = ld_type;
> + if (ld_type->set_layoutdriver
> + && ld_type->set_layoutdriver(server, mntfh)) {
> + printk(KERN_ERR "NFS: %s: Error initializing
> pNFS layout "
> + "driver %u.\n", __func__, id);
> + module_put(ld_type->owner);
> goto out_no_driver;
> }
> - }
> - server->pnfs_curr_ld = ld_type;
> - if (ld_type->set_layoutdriver
> - && ld_type->set_layoutdriver(server, mntfh)) {
> - printk(KERN_ERR "NFS: %s: Error initializing pNFS
> layout "
> - "driver %u.\n", __func__, id);
> - module_put(ld_type->owner);
> - goto out_no_driver;
> - }
> - /* Bump the MDS count */
> - atomic_inc(&server->nfs_client->cl_mds_count);
> + /* Bump the MDS count */
> + atomic_inc(&server->nfs_client->cl_mds_count);
>
> - dprintk("%s: pNFS module for %u set\n", __func__, id);
> - return;
> + dprintk("%s: pNFS module for %u set\n", __func__,
> id);
> + return;
> + }
>
> out_no_driver:
> dprintk("%s: Using NFSv4 I/O\n", __func__);
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 78c9351..e7609c3 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -235,7 +235,7 @@ void pnfs_get_layout_hdr(struct pnfs_layout_hdr
> *lo);
> void pnfs_put_lseg(struct pnfs_layout_segment *lseg);
> void pnfs_put_lseg_locked(struct pnfs_layout_segment *lseg);
>
> -void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh
> *, u32);
> +void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh
> *, u32 *);
> void unset_pnfs_layoutdriver(struct nfs_server *);
> void pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *,
> struct nfs_page *);
> int pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc);
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 52faf7e..6c88745 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -124,6 +124,8 @@ struct nfs_fattr {
> | NFS_ATTR_FATTR_SPACE_USED \
> | NFS_ATTR_FATTR_V4_SECURITY_LABEL)
>
> +#define NFS_MAX_LAYOUT_TYPES 32
There are only RFCs for 4 layout types today. Where does the number
'32' come from?
> +
> /*
> * Info on the file system
> */
> @@ -139,7 +141,7 @@ struct nfs_fsinfo {
> __u64 maxfilesize;
> struct timespec time_delta; /* server time
> granularity */
> __u32 lease_time; /* in seconds */
> - __u32 layouttype; /* supported pnfs
> layout driver */
> + __u32 layouttype[NFS_MAX_LAYOUT_TYPES
> ]; /* supported pnfs layout drivers */
> __u32 blksize; /* preferred pnfs io
> block size */
> };
>
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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