[PATCH] NFSv4: add support for rdattr_error in NFSv4 readdir requests.

 Request RDATTR_ERROR as an attribute in readdir to distinguish between a
 directory being within an absent filesystem or one (or more) of its entries.

 Signed-off-by: Manoj Naik <manoj@almaden.ibm.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 325cd6d..4d655d2 100644 (file)
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1014,6 +1014,10 @@ static int encode_read(struct xdr_stream *xdr, const struct nfs_readargs *args)
 static int encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg *readdir, struct rpc_rqst *req)
 {
        struct rpc_auth *auth = req->rq_task->tk_auth;
+       uint32_t attrs[2] = {
+               FATTR4_WORD0_RDATTR_ERROR|FATTR4_WORD0_FILEID,
+               FATTR4_WORD1_MOUNTED_ON_FILEID,
+       };
        int replen;
        uint32_t *p;
 
@@ -1024,13 +1028,13 @@ static int encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
        WRITE32(readdir->count >> 1);  /* We're not doing readdirplus */
        WRITE32(readdir->count);
        WRITE32(2);
-       if (readdir->bitmask[1] & FATTR4_WORD1_MOUNTED_ON_FILEID) {
-               WRITE32(0);
-               WRITE32(FATTR4_WORD1_MOUNTED_ON_FILEID);
-       } else {
-               WRITE32(FATTR4_WORD0_FILEID);
-               WRITE32(0);
-       }
+       /* Switch to mounted_on_fileid if the server supports it */
+       if (readdir->bitmask[1] & FATTR4_WORD1_MOUNTED_ON_FILEID)
+               attrs[0] &= ~FATTR4_WORD0_FILEID;
+       else
+               attrs[1] &= ~FATTR4_WORD1_MOUNTED_ON_FILEID;
+       WRITE32(attrs[0] & readdir->bitmask[0]);
+       WRITE32(attrs[1] & readdir->bitmask[1]);
 
        /* set up reply kvec
         *    toplevel_status + taglen + rescount + OP_PUTFH + status
@@ -4060,6 +4064,12 @@ uint32_t *nfs4_decode_dirent(uint32_t *p, struct nfs_entry *entry, int plus)
        }
        len = XDR_QUADLEN(ntohl(*p++)); /* attribute buffer length */
        if (len > 0) {
+               if (bitmap[0] & FATTR4_WORD0_RDATTR_ERROR) {
+                       bitmap[0] &= ~FATTR4_WORD0_RDATTR_ERROR;
+                       /* Ignore the return value of rdattr_error for now */
+                       p++;
+                       len--;
+               }
                if (bitmap[0] == 0 && bitmap[1] == FATTR4_WORD1_MOUNTED_ON_FILEID)
                        xdr_decode_hyper(p, &entry->ino);
                else if (bitmap[0] == FATTR4_WORD0_FILEID)