NFS4: on a O_EXCL OPEN make sure SETATTR sets the fields holding the verifier

The Linux NFS4 client simply skips over the bitmask in an O_EXCL open
call and so it doesn't bother to reset any fields that may be holding
the verifier. This patch has us save the first two words of the bitmask
(which is all the current client has #defines for). The client then
later checks this bitmask and turns on the appropriate flags in the
sattr->ia_verify field for the following SETATTR call.

This patch only currently checks to see if the server used the atime
and mtime slots for the verifier (which is what the Linux server uses
for this). I'm not sure of what other fields the server could
reasonably use, but adding checks for others should be trivial.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

4 files changed, 29 insertions, 2 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3cc75445a68d..fee2d14b158b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -943,6 +943,22 @@ static struct nfs4_state *nfs4_open_delegated(struct inode *inode, int flags, st
 }
 
 /*
+ * on an EXCLUSIVE create, the server should send back a bitmask with FATTR4-*
+ * fields corresponding to attributes that were used to store the verifier.
+ * Make sure we clobber those fields in the later setattr call
+ */
+static inline void nfs4_exclusive_attrset(struct nfs4_opendata *opendata, struct iattr *sattr)
+{
+        if ((opendata->o_res.attrset[1] & FATTR4_WORD1_TIME_ACCESS) &&
+            !(sattr->ia_valid & ATTR_ATIME_SET))
+                sattr->ia_valid |= ATTR_ATIME;
+
+        if ((opendata->o_res.attrset[1] & FATTR4_WORD1_TIME_MODIFY) &&
+            !(sattr->ia_valid & ATTR_MTIME_SET))
+                sattr->ia_valid |= ATTR_MTIME;
+}
+
+/*
  * Returns a referenced nfs4_state
  */
 static int _nfs4_do_open(struct inode *dir, struct path *path, int flags, struct iattr *sattr, struct rpc_cred *cred, struct nfs4_state **res)
@@ -973,6 +989,9 @@ static int _nfs4_do_open(struct inode *dir, struct path *path, int flags, struct
         if (status != 0)
                 goto err_opendata_free;
 
+        if (opendata->o_arg.open_flags & O_EXCL)
+                nfs4_exclusive_attrset(opendata, sattr);
+
         status = -ENOMEM;
         state = nfs4_opendata_to_nfs4_state(opendata);
         if (state == NULL)
@@ -1784,6 +1803,7 @@ nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                 status = nfs4_do_setattr(state->inode, &fattr, sattr, state);
                 if (status == 0)
                         nfs_setattr_update_inode(state->inode, sattr);
+                nfs_post_op_update_inode(state->inode, &fattr);
         }
         if (status == 0 && (nd->flags & LOOKUP_OPEN) != 0)
                 status = nfs4_intent_set_file(nd, &path, state);
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 8003c91ccb9a..1fcca516e6ee 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3269,7 +3269,7 @@ static int decode_delegation(struct xdr_stream *xdr, struct nfs_openres *res)
 static int decode_open(struct xdr_stream *xdr, struct nfs_openres *res)
 {
         __be32 *p;
-        uint32_t bmlen;
+        uint32_t savewords, bmlen, i;
         int status;
 
         status = decode_op_hdr(xdr, OP_OPEN);
@@ -3287,7 +3287,12 @@ static int decode_open(struct xdr_stream *xdr, struct nfs_openres *res)
                 goto xdr_error;
 
         READ_BUF(bmlen << 2);
-        p += bmlen;
+        savewords = min_t(uint32_t, bmlen, NFS4_BITMAP_SIZE);
+        for (i = 0; i < savewords; ++i)
+                READ32(res->attrset[i]);
+        for (; i < NFS4_BITMAP_SIZE; i++)
+                res->attrset[i] = 0;
+
         return decode_delegation(xdr, res);
 xdr_error:
         dprintk("%s: Bitmap too large! Length = %u\n", __FUNCTION__, bmlen);
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 7e7f33a38fc0..8726491de154 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -15,6 +15,7 @@
 
 #include <linux/types.h>
 
+#define NFS4_BITMAP_SIZE        2
 #define NFS4_VERIFIER_SIZE      8
 #define NFS4_STATEID_SIZE       16
 #define NFS4_FHSIZE             128
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 10c26ed0db71..f7100df3a690 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -144,6 +144,7 @@ struct nfs_openres {
         nfs4_stateid            delegation;
         __u32                   do_recall;
         __u64                   maxsize;
+        __u32                   attrset[NFS4_BITMAP_SIZE];
 };
 
 /*