nfsd: implement pNFS operations

Add support for the GETDEVICEINFO, LAYOUTGET, LAYOUTCOMMIT and
LAYOUTRETURN NFSv4.1 operations, as well as backing code to manage
outstanding layouts and devices.

Layout management is very straight forward, with a nfs4_layout_stateid
structure that extends nfs4_stid to manage layout stateids as the
top-level structure.  It is linked into the nfs4_file and nfs4_client
structures like the other stateids, and contains a linked list of
layouts that hang of the stateid.  The actual layout operations are
implemented in layout drivers that are not part of this commit, but
will be added later.

The worst part of this commit is the management of the pNFS device IDs,
which suffers from a specification that is not sanely implementable due
to the fact that the device-IDs are global and not bound to an export,
and have a small enough size so that we can't store the fsid portion of
a file handle, and must never be reused.  As we still do need perform all
export authentication and validation checks on a device ID passed to
GETDEVICEINFO we are caught between a rock and a hard place.  To work
around this issue we add a new hash that maps from a 64-bit integer to a
fsid so that we can look up the export to authenticate against it,
a 32-bit integer as a generation that we can bump when changing the device,
and a currently unused 32-bit integer that could be used in the future
to handle more than a single device per export.  Entries in this hash
table are never deleted as we can't reuse the ids anyway, and would have
a severe lifetime problem anyway as Linux export structures are temporary
structures that can go away under load.

Parts of the XDR data, structures and marshaling/unmarshaling code, as
well as many concepts are derived from the old pNFS server implementation
from Andy Adamson, Benny Halevy, Dean Hildebrand, Marc Eshel, Fred Isaman,
Mike Sager, Ricardo Labiaga and many others.

Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 59 insertions, 0 deletions

diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 90a5925bd6ab..0bda93e58e1b 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -428,6 +428,61 @@ struct nfsd4_reclaim_complete {
         u32 rca_one_fs;
 };
 
+struct nfsd4_deviceid {
+        u64                     fsid_idx;
+        u32                     generation;
+        u32                     pad;
+};
+
+struct nfsd4_layout_seg {
+        u32                     iomode;
+        u64                     offset;
+        u64                     length;
+};
+
+struct nfsd4_getdeviceinfo {
+        struct nfsd4_deviceid   gd_devid;       /* request */
+        u32                     gd_layout_type; /* request */
+        u32                     gd_maxcount;    /* request */
+        u32                     gd_notify_types;/* request - response */
+        void                    *gd_device;     /* response */
+};
+
+struct nfsd4_layoutget {
+        u64                     lg_minlength;   /* request */
+        u32                     lg_signal;      /* request */
+        u32                     lg_layout_type; /* request */
+        u32                     lg_maxcount;    /* request */
+        stateid_t               lg_sid;         /* request/response */
+        struct nfsd4_layout_seg lg_seg;         /* request/response */
+        void                    *lg_content;    /* response */
+};
+
+struct nfsd4_layoutcommit {
+        stateid_t               lc_sid;         /* request */
+        struct nfsd4_layout_seg lc_seg;         /* request */
+        u32                     lc_reclaim;     /* request */
+        u32                     lc_newoffset;   /* request */
+        u64                     lc_last_wr;     /* request */
+        struct timespec         lc_mtime;       /* request */
+        u32                     lc_layout_type; /* request */
+        u32                     lc_up_len;      /* layout length */
+        void                    *lc_up_layout;  /* decoded by callback */
+        u32                     lc_size_chg;    /* boolean for response */
+        u64                     lc_newsize;     /* response */
+};
+
+struct nfsd4_layoutreturn {
+        u32                     lr_return_type; /* request */
+        u32                     lr_layout_type; /* request */
+        struct nfsd4_layout_seg lr_seg;         /* request */
+        u32                     lr_reclaim;     /* request */
+        u32                     lrf_body_len;   /* request */
+        void                    *lrf_body;      /* request */
+        stateid_t               lr_sid;         /* request/response */
+        u32                     lrs_present;    /* response */
+};
+
 struct nfsd4_fallocate {
         /* request */
         stateid_t       falloc_stateid;
@@ -491,6 +546,10 @@ struct nfsd4_op {
                 struct nfsd4_reclaim_complete   reclaim_complete;
                 struct nfsd4_test_stateid       test_stateid;
                 struct nfsd4_free_stateid       free_stateid;
+                struct nfsd4_getdeviceinfo      getdeviceinfo;
+                struct nfsd4_layoutget          layoutget;
+                struct nfsd4_layoutcommit       layoutcommit;
+                struct nfsd4_layoutreturn       layoutreturn;
 
                 /* NFSv4.2 */
                 struct nfsd4_fallocate          allocate;