1 files changed, 58 insertions, 0 deletions

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index bd2101d918c8..8b4dfa393f0f 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3978,6 +3978,61 @@ static int decode_getfattr(struct xdr_stream *xdr, struct nfs_fattr *fattr,
         return decode_getfattr_generic(xdr, fattr, NULL, server, may_sleep);
 }
 
+/*
+ * Decode potentially multiple layout types. Currently we only support
+ * one layout driver per file system.
+ */
+static int decode_first_pnfs_layout_type(struct xdr_stream *xdr,
+                                         uint32_t *layouttype)
+{
+        uint32_t *p;
+        int num;
+
+        p = xdr_inline_decode(xdr, 4);
+        if (unlikely(!p))
+                goto out_overflow;
+        num = be32_to_cpup(p);
+
+        /* pNFS is not supported by the underlying file system */
+        if (num == 0) {
+                *layouttype = 0;
+                return 0;
+        }
+        if (num > 1)
+                printk(KERN_INFO "%s: Warning: Multiple pNFS layout drivers "
+                        "per filesystem not supported\n", __func__);
+
+        /* 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);
+        return 0;
+out_overflow:
+        print_overflow_msg(__func__, xdr);
+        return -EIO;
+}
+
+/*
+ * The type of file system exported.
+ * Note we must ensure that layouttype is set in any non-error case.
+ */
+static int decode_attr_pnfstype(struct xdr_stream *xdr, uint32_t *bitmap,
+                                uint32_t *layouttype)
+{
+        int status = 0;
+
+        dprintk("%s: bitmap is %x\n", __func__, bitmap[1]);
+        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);
+                bitmap[1] &= ~FATTR4_WORD1_FS_LAYOUT_TYPES;
+        } else
+                *layouttype = 0;
+        return status;
+}
+
 static int decode_fsinfo(struct xdr_stream *xdr, struct nfs_fsinfo *fsinfo)
 {
         __be32 *savep;
@@ -4006,6 +4061,9 @@ 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);
+        if (status != 0)
+                goto xdr_error;
 
         status = verify_attr_len(xdr, savep, attrlen);
 xdr_error: