NFS/pnfs: Fix pnfs_generic_prepare_to_resend_writes()

commit 221203ce6406273cf00e5c6397257d986c003ee6 upstream.

Instead of making assumptions about the commit verifier contents, change
the commit code to ensure we always check that the verifier was set
by the XDR code.

Fixes: f54bcf2ecee9 ("pnfs: Prepare for flexfiles by pulling out common code")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 16 insertions, 9 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 29b70337dcd9..c61bd3fc723e 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -261,10 +261,10 @@ static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq,
 					 data->ds_commit_index);
 
 	/* verifier not set so always fail */
-	if (verfp->committed < 0)
+	if (verfp->committed < 0 || data->res.verf->committed <= NFS_UNSTABLE)
 		return 1;
 
-	return nfs_direct_cmp_verf(verfp, &data->verf);
+	return nfs_direct_cmp_verf(verfp, data->res.verf);
 }
 
 /**
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 64e4fa33d89f..9956453aa6ff 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -2380,6 +2380,7 @@ static int nfs3_xdr_dec_commit3res(struct rpc_rqst *req,
 				   void *data)
 {
 	struct nfs_commitres *result = data;
+	struct nfs_writeverf *verf = result->verf;
 	enum nfs_stat status;
 	int error;
 
@@ -2392,7 +2393,9 @@ static int nfs3_xdr_dec_commit3res(struct rpc_rqst *req,
 	result->op_status = status;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_writeverf3(xdr, &result->verf->verifier);
+	error = decode_writeverf3(xdr, &verf->verifier);
+	if (!error)
+		verf->committed = NFS_FILE_SYNC;
 out:
 	return error;
 out_status:
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 1c0227c78a7b..c4cf0192d7bb 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4439,11 +4439,14 @@ static int decode_write_verifier(struct xdr_stream *xdr, struct nfs_write_verifi
 
 static int decode_commit(struct xdr_stream *xdr, struct nfs_commitres *res)
 {
+	struct nfs_writeverf *verf = res->verf;
 	int status;
 
 	status = decode_op_hdr(xdr, OP_COMMIT);
 	if (!status)
-		status = decode_write_verifier(xdr, &res->verf->verifier);
+		status = decode_write_verifier(xdr, &verf->verifier);
+	if (!status)
+		verf->committed = NFS_FILE_SYNC;
 	return status;
 }
 
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index d5e4d3cd8c7f..acfb52bc0007 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -30,12 +30,11 @@ EXPORT_SYMBOL_GPL(pnfs_generic_rw_release);
 /* Fake up some data that will cause nfs_commit_release to retry the writes. */
 void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data)
 {
-	struct nfs_page *first = nfs_list_entry(data->pages.next);
+	struct nfs_writeverf *verf = data->res.verf;
 
 	data->task.tk_status = 0;
-	memcpy(&data->verf.verifier, &first->wb_verf,
-	       sizeof(data->verf.verifier));
-	data->verf.verifier.data[0]++; /* ensure verifier mismatch */
+	memset(&verf->verifier, 0, sizeof(verf->verifier));
+	verf->committed = NFS_UNSTABLE;
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_prepare_to_resend_writes);
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index e8152781814d..ce1da8cbac00 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1814,6 +1814,7 @@ static void nfs_commit_done(struct rpc_task *task, void *calldata)
 
 static void nfs_commit_release_pages(struct nfs_commit_data *data)
 {
+	const struct nfs_writeverf *verf = data->res.verf;
 	struct nfs_page	*req;
 	int status = data->task.tk_status;
 	struct nfs_commit_info cinfo;
@@ -1840,7 +1841,8 @@ static void nfs_commit_release_pages(struct nfs_commit_data *data)
 
 		/* Okay, COMMIT succeeded, apparently. Check the verifier
 		 * returned by the server against all stored verfs. */
-		if (!nfs_write_verifier_cmp(&req->wb_verf, &data->verf.verifier)) {
+		if (verf->committed > NFS_UNSTABLE &&
+		    !nfs_write_verifier_cmp(&req->wb_verf, &verf->verifier)) {
 			/* We have a match */
 			if (req->wb_page)
 				nfs_inode_remove_request(req);