[PATCH] knfsd: nfsd4: actually use all the pieces to implement referrals

Use all the pieces set up so far to implement referral support, allowing
return of NFS4ERR_MOVED and fs_locations attribute.

Signed-off-by: Manoj Naik <manoj@almaden.ibm.com>
Signed-off-by: Fred Isaman <iisaman@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 45 insertions, 6 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 0589852007e..41fc241b729 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -60,6 +60,14 @@
 
 #define NFSDDBG_FACILITY                NFSDDBG_XDR
 
+/*
+ * As per referral draft, the fsid for a referral MUST be different from the fsid of the containing
+ * directory in order to indicate to the client that a filesystem boundary is present
+ * We use a fixed fsid for a referral
+ */
+#define NFS4_REFERRAL_FSID_MAJOR        0x8000000ULL
+#define NFS4_REFERRAL_FSID_MINOR        0x8000000ULL
+
 static int
 check_filename(char *str, int len, int err)
 {
@@ -1385,6 +1393,25 @@ nfsd4_encode_aclname(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
         return nfsd4_encode_name(rqstp, whotype, id, group, p, buflen);
 }
 
+#define WORD0_ABSENT_FS_ATTRS (FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_FSID | \
+                              FATTR4_WORD0_RDATTR_ERROR)
+#define WORD1_ABSENT_FS_ATTRS FATTR4_WORD1_MOUNTED_ON_FILEID
+
+static int fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *rdattr_err)
+{
+        /* As per referral draft:  */
+        if (*bmval0 & ~WORD0_ABSENT_FS_ATTRS ||
+            *bmval1 & ~WORD1_ABSENT_FS_ATTRS) {
+                if (*bmval0 & FATTR4_WORD0_RDATTR_ERROR ||
+                    *bmval0 & FATTR4_WORD0_FS_LOCATIONS)
+                        *rdattr_err = NFSERR_MOVED;
+                else
+                        return nfserr_moved;
+        }
+        *bmval0 &= WORD0_ABSENT_FS_ATTRS;
+        *bmval1 &= WORD1_ABSENT_FS_ATTRS;
+        return 0;
+}
 
 /*
  * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
@@ -1407,6 +1434,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         u32 *attrlenp;
         u32 dummy;
         u64 dummy64;
+        u32 rdattr_err = 0;
         u32 *p = buffer;
         int status;
         int aclsupport = 0;
@@ -1416,6 +1444,12 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         BUG_ON(bmval0 & ~NFSD_SUPPORTED_ATTRS_WORD0);
         BUG_ON(bmval1 & ~NFSD_SUPPORTED_ATTRS_WORD1);
 
+        if (exp->ex_fslocs.migrated) {
+                status = fattr_handle_absent_fs(&bmval0, &bmval1, &rdattr_err);
+                if (status)
+                        goto out;
+        }
+
         status = vfs_getattr(exp->ex_mnt, dentry, &stat);
         if (status)
                 goto out_nfserr;
@@ -1461,12 +1495,15 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         attrlenp = p++;                /* to be backfilled later */
 
         if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
+                u32 word0 = NFSD_SUPPORTED_ATTRS_WORD0;
                 if ((buflen -= 12) < 0)
                         goto out_resource;
+                if (!aclsupport)
+                        word0 &= ~FATTR4_WORD0_ACL;
+                if (!exp->ex_fslocs.locations)
+                        word0 &= ~FATTR4_WORD0_FS_LOCATIONS;
                 WRITE32(2);
-                WRITE32(aclsupport ?
-                        NFSD_SUPPORTED_ATTRS_WORD0 :
-                        NFSD_SUPPORTED_ATTRS_WORD0 & ~FATTR4_WORD0_ACL);
+                WRITE32(word0);
                 WRITE32(NFSD_SUPPORTED_ATTRS_WORD1);
         }
         if (bmval0 & FATTR4_WORD0_TYPE) {
@@ -1520,7 +1557,10 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         if (bmval0 & FATTR4_WORD0_FSID) {
                 if ((buflen -= 16) < 0)
                         goto out_resource;
-                if (is_fsid(fhp, rqstp->rq_reffh)) {
+                if (exp->ex_fslocs.migrated) {
+                        WRITE64(NFS4_REFERRAL_FSID_MAJOR);
+                        WRITE64(NFS4_REFERRAL_FSID_MINOR);
+                } else if (is_fsid(fhp, rqstp->rq_reffh)) {
                         WRITE64((u64)exp->ex_fsid);
                         WRITE64((u64)0);
                 } else {
@@ -1543,7 +1583,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         if (bmval0 & FATTR4_WORD0_RDATTR_ERROR) {
                 if ((buflen -= 4) < 0)
                         goto out_resource;
-                WRITE32(0);
+                WRITE32(rdattr_err);
         }
         if (bmval0 & FATTR4_WORD0_ACL) {
                 struct nfs4_ace *ace;
@@ -1970,7 +2010,6 @@ nfsd4_encode_getattr(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_ge
         nfserr = nfsd4_encode_fattr(fhp, fhp->fh_export, fhp->fh_dentry,
                                     resp->p, &buflen, getattr->ga_bmval,
                                     resp->rqstp);
-
         if (!nfserr)
                 resp->p += buflen;
         return nfserr;