Ask for time_delta during fsinfo probe

Used by the client to determine if the server has a granular enough
time stamp.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 22 insertions, 1 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f5ab216e8870..e87fe612ca18 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -129,7 +129,7 @@ const u32 nfs4_fsinfo_bitmap[2] = { FATTR4_WORD0_MAXFILESIZE
                         | FATTR4_WORD0_MAXREAD
                         | FATTR4_WORD0_MAXWRITE
                         | FATTR4_WORD0_LEASE_TIME,
-                        0
+                        FATTR4_WORD1_TIME_DELTA
 };
 
 const u32 nfs4_fs_locations_bitmap[2] = {
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 1e5d68e36e07..7131c761d85c 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3582,6 +3582,24 @@ static int decode_attr_time_metadata(struct xdr_stream *xdr, uint32_t *bitmap, s
         return status;
 }
 
+static int decode_attr_time_delta(struct xdr_stream *xdr, uint32_t *bitmap,
+                                  struct timespec *time)
+{
+        int status = 0;
+
+        time->tv_sec = 0;
+        time->tv_nsec = 0;
+        if (unlikely(bitmap[1] & (FATTR4_WORD1_TIME_DELTA - 1U)))
+                return -EIO;
+        if (likely(bitmap[1] & FATTR4_WORD1_TIME_DELTA)) {
+                status = decode_attr_time(xdr, time);
+                bitmap[1] &= ~FATTR4_WORD1_TIME_DELTA;
+        }
+        dprintk("%s: time_delta=%ld %ld\n", __func__, (long)time->tv_sec,
+                (long)time->tv_nsec);
+        return status;
+}
+
 static int decode_attr_time_modify(struct xdr_stream *xdr, uint32_t *bitmap, struct timespec *time)
 {
         int status = 0;
@@ -3982,6 +4000,9 @@ static int decode_fsinfo(struct xdr_stream *xdr, struct nfs_fsinfo *fsinfo)
         if ((status = decode_attr_maxwrite(xdr, bitmap, &fsinfo->wtmax)) != 0)
                 goto xdr_error;
         fsinfo->wtpref = fsinfo->wtmax;
+        status = decode_attr_time_delta(xdr, bitmap, &fsinfo->time_delta);
+        if (status != 0)
+                goto xdr_error;
 
         status = verify_attr_len(xdr, savep, attrlen);
 xdr_error: