NFS: Remove nfs_writepage_sync()

Maintaining two parallel ways of doing synchronous writes is rather
pointless. This patch gets rid of the legacy nfs_writepage_sync(), and
replaces it with the faster asynchronous writes.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/file.c

@@ -378,6 +378,12 @@ static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 
 	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 	result = generic_file_aio_write(iocb, iov, nr_segs, pos);
+	/* Return error values for O_SYNC and IS_SYNC() */
+	if (result >= 0 && (IS_SYNC(inode) || (iocb->ki_filp->f_flags & O_SYNC))) {
+		int err = nfs_fsync(iocb->ki_filp, dentry, 1);
+		if (err < 0)
+			result = err;
+	}
 out:
 	return result;
 

fs/nfs/nfs3proc.c

@@ -276,51 +276,6 @@ static int nfs3_proc_read(struct nfs_read_data *rdata)
 	return status;
 }
 
-static int nfs3_proc_write(struct nfs_write_data *wdata)
-{
-	int			rpcflags = wdata->flags;
-	struct inode *		inode = wdata->inode;
-	struct nfs_fattr *	fattr = wdata->res.fattr;
-	struct rpc_message	msg = {
-		.rpc_proc	= &nfs3_procedures[NFS3PROC_WRITE],
-		.rpc_argp	= &wdata->args,
-		.rpc_resp	= &wdata->res,
-		.rpc_cred	= wdata->cred,
-	};
-	int			status;
-
-	dprintk("NFS call  write %d @ %Ld\n", wdata->args.count,
-			(long long) wdata->args.offset);
-	nfs_fattr_init(fattr);
-	status = rpc_call_sync(NFS_CLIENT(inode), &msg, rpcflags);
-	if (status >= 0)
-		nfs_post_op_update_inode(inode, fattr);
-	dprintk("NFS reply write: %d\n", status);
-	return status < 0? status : wdata->res.count;
-}
-
-static int nfs3_proc_commit(struct nfs_write_data *cdata)
-{
-	struct inode *		inode = cdata->inode;
-	struct nfs_fattr *	fattr = cdata->res.fattr;
-	struct rpc_message	msg = {
-		.rpc_proc	= &nfs3_procedures[NFS3PROC_COMMIT],
-		.rpc_argp	= &cdata->args,
-		.rpc_resp	= &cdata->res,
-		.rpc_cred	= cdata->cred,
-	};
-	int			status;
-
-	dprintk("NFS call  commit %d @ %Ld\n", cdata->args.count,
-			(long long) cdata->args.offset);
-	nfs_fattr_init(fattr);
-	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
-	if (status >= 0)
-		nfs_post_op_update_inode(inode, fattr);
-	dprintk("NFS reply commit: %d\n", status);
-	return status;
-}
-
 /*
  * Create a regular file.
  * For now, we don't implement O_EXCL.
@@ -901,8 +856,6 @@ const struct nfs_rpc_ops nfs_v3_clientops = {
 	.access		= nfs3_proc_access,
 	.readlink	= nfs3_proc_readlink,
 	.read		= nfs3_proc_read,
-	.write		= nfs3_proc_write,
-	.commit		= nfs3_proc_commit,
 	.create		= nfs3_proc_create,
 	.remove		= nfs3_proc_remove,
 	.unlink_setup	= nfs3_proc_unlink_setup,

fs/nfs/nfs4proc.c

@@ -1775,89 +1775,6 @@ static int nfs4_proc_read(struct nfs_read_data *rdata)
 	return err;
 }
 
-static int _nfs4_proc_write(struct nfs_write_data *wdata)
-{
-	int rpcflags = wdata->flags;
-	struct inode *inode = wdata->inode;
-	struct nfs_fattr *fattr = wdata->res.fattr;
-	struct nfs_server *server = NFS_SERVER(inode);
-	struct rpc_message msg = {
-		.rpc_proc	= &nfs4_procedures[NFSPROC4_CLNT_WRITE],
-		.rpc_argp	= &wdata->args,
-		.rpc_resp	= &wdata->res,
-		.rpc_cred	= wdata->cred,
-	};
-	int status;
-
-	dprintk("NFS call  write %d @ %Ld\n", wdata->args.count,
-			(long long) wdata->args.offset);
-
-	wdata->args.bitmask = server->attr_bitmask;
-	wdata->res.server = server;
-	wdata->timestamp = jiffies;
-	nfs_fattr_init(fattr);
-	status = rpc_call_sync(server->client, &msg, rpcflags);
-	dprintk("NFS reply write: %d\n", status);
-	if (status < 0)
-		return status;
-	renew_lease(server, wdata->timestamp);
-	nfs_post_op_update_inode(inode, fattr);
-	return wdata->res.count;
-}
-
-static int nfs4_proc_write(struct nfs_write_data *wdata)
-{
-	struct nfs4_exception exception = { };
-	int err;
-	do {
-		err = nfs4_handle_exception(NFS_SERVER(wdata->inode),
-				_nfs4_proc_write(wdata),
-				&exception);
-	} while (exception.retry);
-	return err;
-}
-
-static int _nfs4_proc_commit(struct nfs_write_data *cdata)
-{
-	struct inode *inode = cdata->inode;
-	struct nfs_fattr *fattr = cdata->res.fattr;
-	struct nfs_server *server = NFS_SERVER(inode);
-	struct rpc_message msg = {
-		.rpc_proc	= &nfs4_procedures[NFSPROC4_CLNT_COMMIT],
-		.rpc_argp	= &cdata->args,
-		.rpc_resp	= &cdata->res,
-		.rpc_cred	= cdata->cred,
-	};
-	int status;
-
-	dprintk("NFS call  commit %d @ %Ld\n", cdata->args.count,
-			(long long) cdata->args.offset);
-
-	cdata->args.bitmask = server->attr_bitmask;
-	cdata->res.server = server;
-	cdata->timestamp = jiffies;
-	nfs_fattr_init(fattr);
-	status = rpc_call_sync(server->client, &msg, 0);
-	if (status >= 0)
-		renew_lease(server, cdata->timestamp);
-	dprintk("NFS reply commit: %d\n", status);
-	if (status >= 0)
-		nfs_post_op_update_inode(inode, fattr);
-	return status;
-}
-
-static int nfs4_proc_commit(struct nfs_write_data *cdata)
-{
-	struct nfs4_exception exception = { };
-	int err;
-	do {
-		err = nfs4_handle_exception(NFS_SERVER(cdata->inode),
-				_nfs4_proc_commit(cdata),
-				&exception);
-	} while (exception.retry);
-	return err;
-}
-
 /*
  * Got race?
  * We will need to arrange for the VFS layer to provide an atomic open.
@@ -3730,8 +3647,6 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
 	.access		= nfs4_proc_access,
 	.readlink	= nfs4_proc_readlink,
 	.read		= nfs4_proc_read,
-	.write		= nfs4_proc_write,
-	.commit		= nfs4_proc_commit,
 	.create		= nfs4_proc_create,
 	.remove		= nfs4_proc_remove,
 	.unlink_setup	= nfs4_proc_unlink_setup,

fs/nfs/proc.c

@@ -215,32 +215,6 @@ static int nfs_proc_read(struct nfs_read_data *rdata)
 	return status;
 }
 
-static int nfs_proc_write(struct nfs_write_data *wdata)
-{
-	int			flags = wdata->flags;
-	struct inode *		inode = wdata->inode;
-	struct nfs_fattr *	fattr = wdata->res.fattr;
-	struct rpc_message	msg = {
-		.rpc_proc	= &nfs_procedures[NFSPROC_WRITE],
-		.rpc_argp	= &wdata->args,
-		.rpc_resp	= &wdata->res,
-		.rpc_cred	= wdata->cred,
-	};
-	int			status;
-
-	dprintk("NFS call  write %d @ %Ld\n", wdata->args.count,
-			(long long) wdata->args.offset);
-	nfs_fattr_init(fattr);
-	status = rpc_call_sync(NFS_CLIENT(inode), &msg, flags);
-	if (status >= 0) {
-		nfs_post_op_update_inode(inode, fattr);
-		wdata->res.count = wdata->args.count;
-		wdata->verf.committed = NFS_FILE_SYNC;
-	}
-	dprintk("NFS reply write: %d\n", status);
-	return status < 0? status : wdata->res.count;
-}
-
 static int
 nfs_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
 		int flags, struct nameidata *nd)
@@ -693,8 +667,6 @@ const struct nfs_rpc_ops nfs_v2_clientops = {
 	.access		= NULL,		       /* access */
 	.readlink	= nfs_proc_readlink,
 	.read		= nfs_proc_read,
-	.write		= nfs_proc_write,
-	.commit		= NULL,		       /* commit */
 	.create		= nfs_proc_create,
 	.remove		= nfs_proc_remove,
 	.unlink_setup	= nfs_proc_unlink_setup,

fs/nfs/write.c

@@ -210,78 +210,6 @@ static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int
 	SetPageUptodate(page);
 }
 
-/*
- * Write a page synchronously.
- * Offset is the data offset within the page.
- */
-static int nfs_writepage_sync(struct nfs_open_context *ctx, struct page *page,
-		unsigned int offset, unsigned int count, int how)
-{
-	struct inode *inode = page->mapping->host;
-	unsigned int	wsize = NFS_SERVER(inode)->wsize;
-	int		result, written = 0;
-	struct nfs_write_data *wdata;
-
-	wdata = nfs_writedata_alloc(wsize);
-	if (!wdata)
-		return -ENOMEM;
-
-	wdata->flags = how;
-	wdata->cred = ctx->cred;
-	wdata->inode = inode;
-	wdata->args.fh = NFS_FH(inode);
-	wdata->args.context = ctx;
-	wdata->args.pages = &page;
-	wdata->args.stable = NFS_FILE_SYNC;
-	wdata->args.pgbase = offset;
-	wdata->args.count = wsize;
-	wdata->res.fattr = &wdata->fattr;
-	wdata->res.verf = &wdata->verf;
-
-	dprintk("NFS:      nfs_writepage_sync(%s/%Ld %d@%Ld)\n",
-		inode->i_sb->s_id,
-		(long long)NFS_FILEID(inode),
-		count, (long long)(page_offset(page) + offset));
-
-	set_page_writeback(page);
-	nfs_begin_data_update(inode);
-	do {
-		if (count < wsize)
-			wdata->args.count = count;
-		wdata->args.offset = page_offset(page) + wdata->args.pgbase;
-
-		result = NFS_PROTO(inode)->write(wdata);
-
-		if (result < 0) {
-			/* Must mark the page invalid after I/O error */
-			ClearPageUptodate(page);
-			goto io_error;
-		}
-		if (result < wdata->args.count)
-			printk(KERN_WARNING "NFS: short write, count=%u, result=%d\n",
-					wdata->args.count, result);
-
-		wdata->args.offset += result;
-	        wdata->args.pgbase += result;
-		written += result;
-		count -= result;
-		nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, result);
-	} while (count);
-	/* Update file length */
-	nfs_grow_file(page, offset, written);
-	/* Set the PG_uptodate flag? */
-	nfs_mark_uptodate(page, offset, written);
-
-	if (PageError(page))
-		ClearPageError(page);
-
-io_error:
-	nfs_end_data_update(inode);
-	end_page_writeback(page);
-	nfs_writedata_release(wdata);
-	return written ? written : result;
-}
-
 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 		unsigned int offset, unsigned int count)
 {
@@ -342,22 +270,12 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc)
 		err = -EBADF;
 		goto out;
 	}
-	lock_kernel();
-	if (!IS_SYNC(inode)) {
-		err = nfs_writepage_setup(ctx, page, 0, offset);
-		if (!wbc->for_writepages)
-			nfs_flush_mapping(page->mapping, wbc, wb_priority(wbc));
-	} else {
-		err = nfs_writepage_sync(ctx, page, 0, offset, wb_priority(wbc));
-		if (err >= 0) {
-			if (err != offset)
-				redirty_page_for_writepage(wbc, page);
-			err = 0;
-		}
-	}
-	unlock_kernel();
+	err = nfs_writepage_setup(ctx, page, 0, offset);
 	put_nfs_open_context(ctx);
+
 out:
+	if (!wbc->for_writepages)
+		nfs_flush_mapping(page->mapping, wbc, wb_priority(wbc));
 	unlock_page(page);
 	return err; 
 }
@@ -777,16 +695,6 @@ int nfs_updatepage(struct file *file, struct page *page,
 		file->f_dentry->d_name.name, count,
 		(long long)(page_offset(page) +offset));
 
-	if (IS_SYNC(inode)) {
-		status = nfs_writepage_sync(ctx, page, offset, count, 0);
-		if (status > 0) {
-			if (offset == 0 && status == PAGE_CACHE_SIZE)
-				SetPageUptodate(page);
-			return 0;
-		}
-		return status;
-	}
-
 	/* If we're not using byte range locks, and we know the page
 	 * is entirely in cache, it may be more efficient to avoid
 	 * fragmenting write requests.

include/linux/nfs_xdr.h

@@ -785,8 +785,6 @@ struct nfs_rpc_ops {
 	int	(*readlink)(struct inode *, struct page *, unsigned int,
 			    unsigned int);
 	int	(*read)    (struct nfs_read_data *);
-	int	(*write)   (struct nfs_write_data *);
-	int	(*commit)  (struct nfs_write_data *);
 	int	(*create)  (struct inode *, struct dentry *,
 			    struct iattr *, int, struct nameidata *);
 	int	(*remove)  (struct inode *, struct qstr *);