NFS: Clean up helper function nfs4_select_rw_stateid()

We want to be able to pass on the information that the page was not
dirtied under a lock. Instead of adding a flag parameter, do this
by passing a pointer to a 'struct nfs_lock_owner' that may be NULL.

Also reuse this structure in struct nfs_lock_context to carry the
fl_owner_t and pid_t.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -547,8 +547,8 @@ EXPORT_SYMBOL_GPL(nfs_getattr);
 static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
 {
 	atomic_set(&l_ctx->count, 1);
-	l_ctx->lockowner = current->files;
-	l_ctx->pid = current->tgid;
+	l_ctx->lockowner.l_owner = current->files;
+	l_ctx->lockowner.l_pid = current->tgid;
 	INIT_LIST_HEAD(&l_ctx->list);
 }
 
@@ -557,9 +557,9 @@ static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context
 	struct nfs_lock_context *pos;
 
 	list_for_each_entry(pos, &ctx->lock_context.list, list) {
-		if (pos->lockowner != current->files)
+		if (pos->lockowner.l_owner != current->files)
 			continue;
-		if (pos->pid != current->tgid)
+		if (pos->lockowner.l_pid != current->tgid)
 			continue;
 		atomic_inc(&pos->count);
 		return pos;

fs/nfs/nfs4_fs.h

@@ -351,7 +351,7 @@ extern void nfs41_handle_server_scope(struct nfs_client *,
 extern void nfs4_put_lock_state(struct nfs4_lock_state *lsp);
 extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);
 extern void nfs4_select_rw_stateid(nfs4_stateid *, struct nfs4_state *,
-		fmode_t, fl_owner_t, pid_t);
+		fmode_t, const struct nfs_lockowner *);
 
 extern struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter, gfp_t gfp_mask);
 extern int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task);

fs/nfs/nfs4proc.c

@@ -2013,8 +2013,12 @@ static int _nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
 	nfs_fattr_init(fattr);
 
 	if (state != NULL) {
+		struct nfs_lockowner lockowner = {
+			.l_owner = current->files,
+			.l_pid = current->tgid,
+		};
 		nfs4_select_rw_stateid(&arg.stateid, state, FMODE_WRITE,
-				current->files, current->tgid);
+				&lockowner);
 	} else if (nfs4_copy_delegation_stateid(&arg.stateid, inode,
 				FMODE_WRITE)) {
 		/* Use that stateid */

fs/nfs/nfs4state.c

@@ -911,14 +911,22 @@ int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl)
 }
 
 static bool nfs4_copy_lock_stateid(nfs4_stateid *dst, struct nfs4_state *state,
-		fl_owner_t fl_owner, pid_t fl_pid)
+		const struct nfs_lockowner *lockowner)
 {
 	struct nfs4_lock_state *lsp;
+	fl_owner_t fl_owner;
+	pid_t fl_pid;
 	bool ret = false;
 
+
+	if (lockowner == NULL)
+		goto out;
+
 	if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
 		goto out;
 
+	fl_owner = lockowner->l_owner;
+	fl_pid = lockowner->l_pid;
 	spin_lock(&state->state_lock);
 	lsp = __nfs4_find_lock_state(state, fl_owner, fl_pid, NFS4_ANY_LOCK_TYPE);
 	if (lsp != NULL && (lsp->ls_flags & NFS_LOCK_INITIALIZED) != 0) {
@@ -946,11 +954,11 @@ static void nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
  * requests.
  */
 void nfs4_select_rw_stateid(nfs4_stateid *dst, struct nfs4_state *state,
-		fmode_t fmode, fl_owner_t fl_owner, pid_t fl_pid)
+		fmode_t fmode, const struct nfs_lockowner *lockowner)
 {
 	if (nfs4_copy_delegation_stateid(dst, state->inode, fmode))
 		return;
-	if (nfs4_copy_lock_stateid(dst, state, fl_owner, fl_pid))
+	if (nfs4_copy_lock_stateid(dst, state, lockowner))
 		return;
 	nfs4_copy_open_stateid(dst, state);
 }

fs/nfs/nfs4xdr.c

@@ -1509,8 +1509,12 @@ static void encode_open_stateid(struct xdr_stream *xdr,
 	nfs4_stateid stateid;
 
 	if (ctx->state != NULL) {
+		const struct nfs_lockowner *lockowner = NULL;
+
+		if (l_ctx != NULL)
+			lockowner = &l_ctx->lockowner;
 		nfs4_select_rw_stateid(&stateid, ctx->state,
-				fmode, l_ctx->lockowner, l_ctx->pid);
+				fmode, lockowner);
 		if (zero_seqid)
 			stateid.seqid = 0;
 		encode_nfs4_stateid(xdr, &stateid);

fs/nfs/pagelist.c

@@ -292,7 +292,9 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
 {
 	if (req->wb_context->cred != prev->wb_context->cred)
 		return false;
-	if (req->wb_lock_context->lockowner != prev->wb_lock_context->lockowner)
+	if (req->wb_lock_context->lockowner.l_owner != prev->wb_lock_context->lockowner.l_owner)
+		return false;
+	if (req->wb_lock_context->lockowner.l_pid != prev->wb_lock_context->lockowner.l_pid)
 		return false;
 	if (req->wb_context->state != prev->wb_context->state)
 		return false;

fs/nfs/write.c

@@ -846,6 +846,7 @@ static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 int nfs_flush_incompatible(struct file *file, struct page *page)
 {
 	struct nfs_open_context *ctx = nfs_file_open_context(file);
+	struct nfs_lock_context *l_ctx;
 	struct nfs_page	*req;
 	int do_flush, status;
 	/*
@@ -860,9 +861,12 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
 		req = nfs_page_find_request(page);
 		if (req == NULL)
 			return 0;
-		do_flush = req->wb_page != page || req->wb_context != ctx ||
-			req->wb_lock_context->lockowner != current->files ||
-			req->wb_lock_context->pid != current->tgid;
+		l_ctx = req->wb_lock_context;
+		do_flush = req->wb_page != page || req->wb_context != ctx;
+		if (l_ctx) {
+			do_flush |= l_ctx->lockowner.l_owner != current->files
+				|| l_ctx->lockowner.l_pid != current->tgid;
+		}
 		nfs_release_request(req);
 		if (!do_flush)
 			return 0;

include/linux/nfs_fs.h

@@ -81,12 +81,16 @@ struct nfs_access_entry {
 	int			mask;
 };
 
+struct nfs_lockowner {
+	fl_owner_t l_owner;
+	pid_t l_pid;
+};
+
 struct nfs_lock_context {
 	atomic_t count;
 	struct list_head list;
 	struct nfs_open_context *open_context;
-	fl_owner_t lockowner;
-	pid_t pid;
+	struct nfs_lockowner lockowner;
 };
 
 struct nfs4_state;