[Ocfs2-tools-devel] [PATCH 17/22] tunefs rework: Add feature_unwritten_extents.c

[Joel Becker]

Enables and disables the unwritten extents feature.

This is the 'unwritten' key to the tunefs option '--fs-features'.

Signed-off-by: Joel Becker <joel.becker at oracle.com>
---
 tunefs.ocfs2/feature_unwritten_extents.c |  209 ++++++++++++++++++++++++++++++
 1 files changed, 209 insertions(+), 0 deletions(-)
 create mode 100644 tunefs.ocfs2/feature_unwritten_extents.c

diff --git a/tunefs.ocfs2/feature_unwritten_extents.c b/tunefs.ocfs2/feature_unwritten_extents.c
new file mode 100644
index 0000000..3b7e61f
--- /dev/null
+++ b/tunefs.ocfs2/feature_unwritten_extents.c
@@ -0,0 +1,209 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * feature_unwritten_extents.c
+ *
+ * ocfs2 tune utility for enabling and disabling the unwritten extents
+ * feature.
+ *
+ * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <inttypes.h>
+#include <assert.h>
+
+#include "ocfs2/ocfs2.h"
+
+#include "libocfs2ne.h"
+
+
+static int enable_unwritten_extents(ocfs2_filesys *fs, int flags)
+{
+	errcode_t ret = 0;
+	struct ocfs2_super_block *super = OCFS2_RAW_SB(fs->fs_super);
+
+	if (ocfs2_writes_unwritten_extents(super)) {
+		verbosef(VL_APP,
+			 "Unwritten extents feature is already enabled; "
+			 "nothing to enable\n");
+		goto out;
+	}
+
+	if (!ocfs2_sparse_alloc(super)) {
+		errorf("Sparse files are not enabled on device \"%s\"; "
+		       "unwritten extents cannot be enabled\n",
+		       fs->fs_devname);
+		ret = TUNEFS_ET_SPARSE_MISSING;
+		goto out;
+	}
+
+	if (!tunefs_interact("Enable the unwritten extents feature on "
+			     "device \"%s\"? ",
+			     fs->fs_devname))
+		goto out;
+
+	OCFS2_SET_RO_COMPAT_FEATURE(super,
+				    OCFS2_FEATURE_RO_COMPAT_UNWRITTEN);
+	tunefs_block_signals();
+	ret = ocfs2_write_super(fs);
+	tunefs_unblock_signals();
+	if (ret)
+		tcom_err(ret, "while writing out the superblock");
+
+out:
+	return ret;
+}
+
+static errcode_t empty_clusters(ocfs2_filesys *fs,
+				uint64_t start_blk,
+				uint32_t num_clusters)
+{
+	errcode_t ret;
+	char *buf = NULL;
+	uint16_t bpc = fs->fs_clustersize / fs->fs_blocksize;
+	uint64_t total_blocks = bpc * num_clusters;
+	uint64_t io_blocks = total_blocks;
+
+	ret = ocfs2_malloc_blocks(fs->fs_io, io_blocks, &buf);
+	if (ret == OCFS2_ET_NO_MEMORY) {
+		io_blocks = bpc;
+		ret = ocfs2_malloc_blocks(fs->fs_io, io_blocks, &buf);
+	}
+	if (ret)
+		goto bail;
+
+	memset(buf, 0, io_blocks * fs->fs_blocksize);
+
+	while (total_blocks) {
+		ret = io_write_block(fs->fs_io, start_blk, io_blocks, buf);
+		if (ret)
+			goto bail;
+
+		total_blocks -= io_blocks;
+		start_blk += io_blocks;
+	}
+
+bail:
+	if (buf)
+		ocfs2_free(&buf);
+
+	return ret;
+}
+
+static errcode_t unwritten_iterate(ocfs2_filesys *fs,
+				   struct ocfs2_dinode *di,
+				   void *unused)
+{
+	errcode_t ret;
+	uint32_t clusters, v_cluster = 0, p_cluster, num_clusters;
+	uint16_t extent_flags;
+	uint64_t p_blkno;
+	ocfs2_cached_inode *ci = NULL;
+
+	clusters = (di->i_size + fs->fs_clustersize -1 ) /
+			fs->fs_clustersize;
+
+	ret = ocfs2_read_cached_inode(fs, di->i_blkno, &ci);
+	if (ret)
+		goto bail;
+
+	while (v_cluster < clusters) {
+		ret = ocfs2_get_clusters(ci,
+					 v_cluster, &p_cluster,
+					 &num_clusters, &extent_flags);
+		if (ret)
+			break;
+
+		if (extent_flags & OCFS2_EXT_UNWRITTEN) {
+			p_blkno = ocfs2_clusters_to_blocks(fs, p_cluster);
+			ret = empty_clusters(fs, p_blkno, num_clusters);
+			if (ret)
+				break;
+
+			tunefs_block_signals();
+			ret = ocfs2_mark_extent_written(fs, di, v_cluster,
+							num_clusters,
+							p_blkno);
+			tunefs_unblock_signals();
+			if (ret)
+				break;
+		}
+
+		v_cluster += num_clusters;
+	}
+
+bail:
+	if (ci)
+		ocfs2_free_cached_inode(fs, ci);
+	return ret;
+}
+
+static errcode_t clear_unwritten_extents(ocfs2_filesys *fs)
+{
+	return tunefs_foreach_inode(fs, S_IFREG, unwritten_iterate, NULL);
+}
+
+static int disable_unwritten_extents(ocfs2_filesys *fs, int flags)
+{
+	errcode_t ret = 0;
+	struct ocfs2_super_block *super = OCFS2_RAW_SB(fs->fs_super);
+
+	if (!ocfs2_writes_unwritten_extents(super)) {
+		verbosef(VL_APP,
+			 "Unwritten extents feature is not enabled; "
+			 "nothing to disable\n");
+		goto out;
+	}
+
+	if (!tunefs_interact("Disable the unwritten extents feature on "
+			     "device \"%s\"? ",
+			     fs->fs_devname))
+		goto out;
+
+	ret = clear_unwritten_extents(fs);
+	if (ret) {
+		tcom_err(ret,
+			 "while trying to clear the unwritten extents on "
+			 "device \"%s\"",
+			 fs->fs_devname);
+		goto out;
+	}
+
+	OCFS2_CLEAR_RO_COMPAT_FEATURE(super,
+				      OCFS2_FEATURE_RO_COMPAT_UNWRITTEN);
+	tunefs_block_signals();
+	ret = ocfs2_write_super(fs);
+	tunefs_unblock_signals();
+	if (ret)
+		tcom_err(ret, "while writing out the superblock");
+
+out:
+	return ret;
+}
+
+DEFINE_TUNEFS_FEATURE_RO_COMPAT(unwritten_extents,
+				OCFS2_FEATURE_RO_COMPAT_UNWRITTEN,
+				TUNEFS_FLAG_RW | TUNEFS_FLAG_ALLOCATION,
+				enable_unwritten_extents,
+				disable_unwritten_extents);
+
+#ifdef DEBUG_EXE
+int main(int argc, char *argv[])
+{
+	return tunefs_feature_main(argc, argv, &unwritten_extents_feature);
+}
+#endif
-- 
1.5.6.3